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|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0801.3359
|
Ezio Maina
|
A. Ballestrero, A. Belhouari, G. Bevilacqua, V. Kashkan, E. Maina
|
PHANTOM: a Monte Carlo event generator for six parton final states at
high energy colliders
|
Version updated to agree with published one in Comp.Phys.Comm
| null |
10.1016/j.cpc.2008.10.005
|
DFTT 13/2007
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
PHANTOM is a tree level Monte Carlo for six parton final states at
proton--proton, proton--antiproton and electron--positron collider at
O(alpha_ew^6) and O(alpha_ew^4*alpha_s^2) including possible interferences
between the two sets of diagrams. This comprehends all purely electroweak
contribution as well as all contributions with one virtual or two external
gluons. It can generate unweighted events for any set of processes and it is
interfaced to parton shower and hadronization packages via the last Les Houches
Accord protocol. It can be used to analyze the physics of boson boson
scattering, Higgs boson production in boson boson fusion, t-tbar and three
boson production.
|
[
{
"created": "Tue, 22 Jan 2008 13:17:06 GMT",
"version": "v1"
},
{
"created": "Mon, 5 Jan 2009 15:36:30 GMT",
"version": "v2"
}
] |
2009-01-05
|
[
[
"Ballestrero",
"A.",
""
],
[
"Belhouari",
"A.",
""
],
[
"Bevilacqua",
"G.",
""
],
[
"Kashkan",
"V.",
""
],
[
"Maina",
"E.",
""
]
] |
PHANTOM is a tree level Monte Carlo for six parton final states at proton--proton, proton--antiproton and electron--positron collider at O(alpha_ew^6) and O(alpha_ew^4*alpha_s^2) including possible interferences between the two sets of diagrams. This comprehends all purely electroweak contribution as well as all contributions with one virtual or two external gluons. It can generate unweighted events for any set of processes and it is interfaced to parton shower and hadronization packages via the last Les Houches Accord protocol. It can be used to analyze the physics of boson boson scattering, Higgs boson production in boson boson fusion, t-tbar and three boson production.
|
2306.12406
|
Guang-Juan Wang
|
Guang-Juan Wang, Zhi Yang, Jia-Jun Wu, Makoto Oka, and Shi-Lin Zhu
|
New insight into the exotic states strongly coupled with the
$D\bar{D}^*$ from the $T^+_{cc}$
|
10 pages, 5 figures, version accepted for publication in Science
Bulletin
| null |
10.1016/j.scib.2024.07.012
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We have investigated the internal structure of the open- and hidden-charmed
($DD^*$/$\bar DD^*$) molecules in the unified framework. We first fit the
experimental lineshape of the $T^+_{cc}$ state and extract the $DD^*$
interaction, from which the $T^+_{cc}$ is assumed to arise solely. Then we
obtain the $D\bar{D}^*$ interaction by charge conjugation. Our results show
that the $D\bar{D}^*$ interaction is attractive but insufficient to form
$X(3872)$ as a bound state. Instead, its formation requires the crucial
involvement of the coupled channel effect between the $D\bar D^*$ and $c\bar c$
components, although the $c\bar c$ accounts for approximately $1\%$ only.
Besides $X(3872)$, we have obtained a higher-energy state around $3957.9$ MeV
with a width of $16.7$ MeV, which may be a potential candidate for the
$X(3940)$. In $J^{PC}=1^{+-}$ sector, we have found two states related to the
iso-scalar $\tilde X(3872)$ and $h_c(2P)$, respectively. Our combined study
provides valuable insights into the nature of these $DD^*$/$D\bar D^*$ exotic
states.
|
[
{
"created": "Wed, 21 Jun 2023 17:44:18 GMT",
"version": "v1"
},
{
"created": "Tue, 2 Jul 2024 14:10:28 GMT",
"version": "v2"
}
] |
2024-08-16
|
[
[
"Wang",
"Guang-Juan",
""
],
[
"Yang",
"Zhi",
""
],
[
"Wu",
"Jia-Jun",
""
],
[
"Oka",
"Makoto",
""
],
[
"Zhu",
"Shi-Lin",
""
]
] |
We have investigated the internal structure of the open- and hidden-charmed ($DD^*$/$\bar DD^*$) molecules in the unified framework. We first fit the experimental lineshape of the $T^+_{cc}$ state and extract the $DD^*$ interaction, from which the $T^+_{cc}$ is assumed to arise solely. Then we obtain the $D\bar{D}^*$ interaction by charge conjugation. Our results show that the $D\bar{D}^*$ interaction is attractive but insufficient to form $X(3872)$ as a bound state. Instead, its formation requires the crucial involvement of the coupled channel effect between the $D\bar D^*$ and $c\bar c$ components, although the $c\bar c$ accounts for approximately $1\%$ only. Besides $X(3872)$, we have obtained a higher-energy state around $3957.9$ MeV with a width of $16.7$ MeV, which may be a potential candidate for the $X(3940)$. In $J^{PC}=1^{+-}$ sector, we have found two states related to the iso-scalar $\tilde X(3872)$ and $h_c(2P)$, respectively. Our combined study provides valuable insights into the nature of these $DD^*$/$D\bar D^*$ exotic states.
|
1311.6719
|
Javier M. Hernandez-Lopez
|
J. M. Hern\'andez-L\'opez, T. A. Valencia-P\'erez
|
Leptonic number violation signature arising from a $Z'$ model with
non-diagonal leptonic couplings
|
11 pages, 21 figures, uses JHEP style
| null | null | null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Within the framework of a $Z'$ model with non-universal leptonic couplings,
we analyze possible signatures of leptonic number violation effects at LHC.
Results are described for leptonic energy distributions, both from its specific
signature and events number, that could allow us to observe this class of
models, under reasonable conditions at LHC.
|
[
{
"created": "Tue, 26 Nov 2013 16:04:54 GMT",
"version": "v1"
}
] |
2013-11-27
|
[
[
"Hernández-López",
"J. M.",
""
],
[
"Valencia-Pérez",
"T. A.",
""
]
] |
Within the framework of a $Z'$ model with non-universal leptonic couplings, we analyze possible signatures of leptonic number violation effects at LHC. Results are described for leptonic energy distributions, both from its specific signature and events number, that could allow us to observe this class of models, under reasonable conditions at LHC.
|
1005.3173
|
Alexander Bakulev P.
|
Alexander P. Bakulev, S. V. Mikhailov, and N. G. Stefanis
|
Pion Distribution Amplitude and Photon-to-Pion Transition Form Factor in
QCD
|
6 pages, 3 figures, talk delivered by the first author at the
International Meeting "Excited QCD'', January 31--February 5, 2010, Tatranska
Lomnica (Slovakia)
|
Acta Phys.Polon.Supp.3:943-948,2010
| null |
RUB-TPII-05/2010
|
hep-ph hep-ex
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We discuss the status of the pion distribution amplitude (DA) in connection
with QCD sum rules and experimental data on the $\gamma^*\gamma^\to \pi^0$
transition form factor. Contents: (a) Pion DA in generalized QCD Sum Rules
(SRs); (b) Light Cone Sum Rules (LCSR) analysis of the CLEO data for the
$\gamma^*\gamma\to\pi^{0}$ transition form factor; (c) Recent lattice QCD data
for the pion DA; (d) BaBar data---a challenge for QCD?
|
[
{
"created": "Tue, 18 May 2010 12:40:02 GMT",
"version": "v1"
}
] |
2010-12-17
|
[
[
"Bakulev",
"Alexander P.",
""
],
[
"Mikhailov",
"S. V.",
""
],
[
"Stefanis",
"N. G.",
""
]
] |
We discuss the status of the pion distribution amplitude (DA) in connection with QCD sum rules and experimental data on the $\gamma^*\gamma^\to \pi^0$ transition form factor. Contents: (a) Pion DA in generalized QCD Sum Rules (SRs); (b) Light Cone Sum Rules (LCSR) analysis of the CLEO data for the $\gamma^*\gamma\to\pi^{0}$ transition form factor; (c) Recent lattice QCD data for the pion DA; (d) BaBar data---a challenge for QCD?
|
hep-ph/9606290
|
Wim Beenakker
|
W.Beenakker (Leiden) and R.H\"opker (DESY)
|
SUSY-QCD corrections in the squark-gluino sector
|
6 two-column pages, tar'ed gzip'ed uuencoded files, LaTeX, 7
Encapsulated Postscript figures, uses epsfig and espcrc2. To appear in the
proceedings of the 1996 Zeuthen Workshop on Elementary Particle Theory: "QCD
and QED in Higher Orders", J.Bl\"umlein, F.Jegerlehner, and T.Riemann eds.
Complete postscript file available at
http://rulgm4.LeidenUniv.nl/preprints.html
|
Nucl.Phys.Proc.Suppl. 51C (1996) 261-266
|
10.1016/S0920-5632(96)90034-1
| null |
hep-ph
| null |
A status report is given of the calculations of next-to-leading-order ($N=1$)
supersymmetric QCD corrections to the production of squarks and gluinos in
$p\bar{p}/pp$ collisions. The implementation of these SUSY-QCD corrections
leads to more stable theoretical predictions and to a substantial increase of
the production cross-sections. In addition we give a discussion of the use of
the $\overline{MS}$ scheme for renormalizing the coupling constants in the QCD
sector of ($N=1$) supersymmetric theories.
|
[
{
"created": "Mon, 10 Jun 1996 14:35:24 GMT",
"version": "v1"
}
] |
2015-06-25
|
[
[
"Beenakker",
"W.",
"",
"Leiden"
],
[
"Höpker",
"R.",
"",
"DESY"
]
] |
A status report is given of the calculations of next-to-leading-order ($N=1$) supersymmetric QCD corrections to the production of squarks and gluinos in $p\bar{p}/pp$ collisions. The implementation of these SUSY-QCD corrections leads to more stable theoretical predictions and to a substantial increase of the production cross-sections. In addition we give a discussion of the use of the $\overline{MS}$ scheme for renormalizing the coupling constants in the QCD sector of ($N=1$) supersymmetric theories.
|
1609.07788
|
Juri Fiaschi
|
Elena Accomando, Juri Fiaschi, Francesco Hautmann, Stefano Moretti,
Claire Shepherd-Themistocleous
|
Impact of the Photon-Initiated process on Z'-boson searches in di-lepton
final states at the LHC
|
8 pages. Contribution to the proceedings of the 38th International
Conference of High Energy Physics (ICHEP), Chicago, Aug. 3-10, 2016
| null | null | null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We discuss the effect of the Photon Initiated (PI) process on the dilepton
channel at the LHC. Adopting various QED PDF sets, we evaluate the contribution
produced by two resolved photons which is not included in the Equivalent Photon
Approximation (EPA). We compare the PI central value as predicted by the CTEQ,
MRST and NNPDF collaborations. With the NNPDF2.3QED set of replicas we also
estimate the PDF uncertainties on the PI central value. We show the effect of
the inclusion of the PI contribution and its PDF uncertainties on neutral heavy
Z'-boson searches. We explore the two scenarios of narrow and broad resonances,
including in the analysis the reconstructed Forward-Backward Asymmetry
observable, the latter being less affected by systematics effects.
|
[
{
"created": "Sun, 25 Sep 2016 19:42:46 GMT",
"version": "v1"
}
] |
2016-09-27
|
[
[
"Accomando",
"Elena",
""
],
[
"Fiaschi",
"Juri",
""
],
[
"Hautmann",
"Francesco",
""
],
[
"Moretti",
"Stefano",
""
],
[
"Shepherd-Themistocleous",
"Claire",
""
]
] |
We discuss the effect of the Photon Initiated (PI) process on the dilepton channel at the LHC. Adopting various QED PDF sets, we evaluate the contribution produced by two resolved photons which is not included in the Equivalent Photon Approximation (EPA). We compare the PI central value as predicted by the CTEQ, MRST and NNPDF collaborations. With the NNPDF2.3QED set of replicas we also estimate the PDF uncertainties on the PI central value. We show the effect of the inclusion of the PI contribution and its PDF uncertainties on neutral heavy Z'-boson searches. We explore the two scenarios of narrow and broad resonances, including in the analysis the reconstructed Forward-Backward Asymmetry observable, the latter being less affected by systematics effects.
|
2103.14043
|
Nathaniel Craig
|
Hind Al Ali, Nima Arkani-Hamed, Ian Banta, Sean Benevedes, Dario
Buttazzo, Tianji Cai, Junyi Cheng, Timothy Cohen, Nathaniel Craig, Majid
Ekhterachian, JiJi Fan, Matthew Forslund, Isabel Garcia Garcia, Samuel
Homiller, Seth Koren, Giacomo Koszegi, Zhen Liu, Qianshu Lu, Kun-Feng Lyu,
Alberto Mariotti, Amara McCune, Patrick Meade, Isobel Ojalvo, Umut Oktem,
Diego Redigolo, Matthew Reece, Filippo Sala, Raman Sundrum, Dave Sutherland,
Andrea Tesi, Timothy Trott, Chris Tully, Lian-Tao Wang, Menghang Wang
|
The Muon Smasher's Guide
|
105 pages, 41 figures, 5 tables
| null |
10.1088/1361-6633/ac6678
| null |
hep-ph hep-ex
|
http://creativecommons.org/licenses/by/4.0/
|
We lay out a comprehensive physics case for a future high-energy muon
collider, exploring a range of collision energies (from 1 to 100 TeV) and
luminosities. We highlight the advantages of such a collider over proposed
alternatives. We show how one can leverage both the point-like nature of the
muons themselves as well as the cloud of electroweak radiation that surrounds
the beam to blur the dichotomy between energy and precision in the search for
new physics. The physics case is buttressed by a range of studies with
applications to electroweak symmetry breaking, dark matter, and the naturalness
of the weak scale. Furthermore, we make sharp connections with complementary
experiments that are probing new physics effects using electric dipole moments,
flavor violation, and gravitational waves. An extensive appendix provides cross
section predictions as a function of the center-of-mass energy for many
canonical simplified models.
|
[
{
"created": "Thu, 25 Mar 2021 18:00:01 GMT",
"version": "v1"
}
] |
2022-07-27
|
[
[
"Ali",
"Hind Al",
""
],
[
"Arkani-Hamed",
"Nima",
""
],
[
"Banta",
"Ian",
""
],
[
"Benevedes",
"Sean",
""
],
[
"Buttazzo",
"Dario",
""
],
[
"Cai",
"Tianji",
""
],
[
"Cheng",
"Junyi",
""
],
[
"Cohen",
"Timothy",
""
],
[
"Craig",
"Nathaniel",
""
],
[
"Ekhterachian",
"Majid",
""
],
[
"Fan",
"JiJi",
""
],
[
"Forslund",
"Matthew",
""
],
[
"Garcia",
"Isabel Garcia",
""
],
[
"Homiller",
"Samuel",
""
],
[
"Koren",
"Seth",
""
],
[
"Koszegi",
"Giacomo",
""
],
[
"Liu",
"Zhen",
""
],
[
"Lu",
"Qianshu",
""
],
[
"Lyu",
"Kun-Feng",
""
],
[
"Mariotti",
"Alberto",
""
],
[
"McCune",
"Amara",
""
],
[
"Meade",
"Patrick",
""
],
[
"Ojalvo",
"Isobel",
""
],
[
"Oktem",
"Umut",
""
],
[
"Redigolo",
"Diego",
""
],
[
"Reece",
"Matthew",
""
],
[
"Sala",
"Filippo",
""
],
[
"Sundrum",
"Raman",
""
],
[
"Sutherland",
"Dave",
""
],
[
"Tesi",
"Andrea",
""
],
[
"Trott",
"Timothy",
""
],
[
"Tully",
"Chris",
""
],
[
"Wang",
"Lian-Tao",
""
],
[
"Wang",
"Menghang",
""
]
] |
We lay out a comprehensive physics case for a future high-energy muon collider, exploring a range of collision energies (from 1 to 100 TeV) and luminosities. We highlight the advantages of such a collider over proposed alternatives. We show how one can leverage both the point-like nature of the muons themselves as well as the cloud of electroweak radiation that surrounds the beam to blur the dichotomy between energy and precision in the search for new physics. The physics case is buttressed by a range of studies with applications to electroweak symmetry breaking, dark matter, and the naturalness of the weak scale. Furthermore, we make sharp connections with complementary experiments that are probing new physics effects using electric dipole moments, flavor violation, and gravitational waves. An extensive appendix provides cross section predictions as a function of the center-of-mass energy for many canonical simplified models.
|
0907.0482
|
Joseph Schechter
|
Amir H. Fariborz, N.W. Park, Joseph Schechter, and M. Naeem Shahid
|
Gauged linear sigma model and pion-pion scattering
|
19 pages, 9 figures
| null |
10.1103/PhysRevD.80.113001
|
SU-4252-889
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
A simple gauged linear sigma model with several parameters to take the
symmetry breaking and the mass differences between the vector meson and the
axial vector meson into account is considered here as a possibly useful
template for the role of a light scalar in QCD as well as for (at a different
scale) an effective Higgs sector for some recently proposed walking technicolor
models. An analytic procedure is first developed for relating the Lagrangian
parameters to four well established (in the QCD application) experimental
inputs. One simple equation distinguishes three different cases:1. QCD with
axial vector particle heavier than vector particle, 2. possible technicolor
model with vector particle heavier than the axial vector one, 3. the unphysical
QCD case where both the KSRF and Weinberg relations hold. The model is applied
to the s-wave pion-pion scattering in QCD. Both the near threshold region and
(with an assumed unitarization) theglobal region up to about 800 MeV are
considered. It is noted that there is a little tension between the choice of
bare sigma mass parameter for describing these two regions. If a reasonable
globa fit is made, there is some loss of precision in the near threshold
region.
|
[
{
"created": "Thu, 2 Jul 2009 20:14:24 GMT",
"version": "v1"
}
] |
2015-05-13
|
[
[
"Fariborz",
"Amir H.",
""
],
[
"Park",
"N. W.",
""
],
[
"Schechter",
"Joseph",
""
],
[
"Shahid",
"M. Naeem",
""
]
] |
A simple gauged linear sigma model with several parameters to take the symmetry breaking and the mass differences between the vector meson and the axial vector meson into account is considered here as a possibly useful template for the role of a light scalar in QCD as well as for (at a different scale) an effective Higgs sector for some recently proposed walking technicolor models. An analytic procedure is first developed for relating the Lagrangian parameters to four well established (in the QCD application) experimental inputs. One simple equation distinguishes three different cases:1. QCD with axial vector particle heavier than vector particle, 2. possible technicolor model with vector particle heavier than the axial vector one, 3. the unphysical QCD case where both the KSRF and Weinberg relations hold. The model is applied to the s-wave pion-pion scattering in QCD. Both the near threshold region and (with an assumed unitarization) theglobal region up to about 800 MeV are considered. It is noted that there is a little tension between the choice of bare sigma mass parameter for describing these two regions. If a reasonable globa fit is made, there is some loss of precision in the near threshold region.
|
hep-ph/9211240
| null |
Rohini M. Godbole and Probir Roy
|
Debajyoti Choudhury
| null |
Phys.Lett. B308 (1993) 394-402; Erratum-ibid. B314 (1993) 482
|
10.1016/0370-2693(93)91304-6
| null |
hep-ph
| null |
Gluon fusion into a very heavy neutrino pair by Higgs exchange is shown to
lead to substantial production cross sections at $pp$ supercolliders even
without any extra generation of quarks. Rates are calculated for scalar as well
as pseudoscalar Higgs. The angular correlation between dileptons emerging from
the decays of the neutrinos shows distinctive features for Dirac and Majorana
neutrinos as well as for scalar and pseudoscalar Higgs.
|
[
{
"created": "Thu, 12 Nov 1992 14:52:00 GMT",
"version": "v1"
}
] |
2009-10-22
|
[
[
"Godbole",
"Rohini M.",
""
],
[
"Roy",
"Probir",
""
]
] |
Gluon fusion into a very heavy neutrino pair by Higgs exchange is shown to lead to substantial production cross sections at $pp$ supercolliders even without any extra generation of quarks. Rates are calculated for scalar as well as pseudoscalar Higgs. The angular correlation between dileptons emerging from the decays of the neutrinos shows distinctive features for Dirac and Majorana neutrinos as well as for scalar and pseudoscalar Higgs.
|
1508.03463
|
Hiroaki Kohyama
|
Hiroaki Kohyama
|
Numerical solution for the Schwinger-Dyson equation at finite
temperature in Abelian gauge theory
|
13 pages, 6 figures
| null | null | null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We present the exact numerical solutions for the Schwinger-Dyson equations at
finite temperature with general gauge in Abelian gauge theory. We then study
the chiral phase transition on temperature from the obtained solutions. We find
that, within the quenched Schwinger-Dyson equations, there exists substantial
gauge dependence on the solutions and the critical temperature.
|
[
{
"created": "Fri, 14 Aug 2015 10:31:33 GMT",
"version": "v1"
}
] |
2015-08-17
|
[
[
"Kohyama",
"Hiroaki",
""
]
] |
We present the exact numerical solutions for the Schwinger-Dyson equations at finite temperature with general gauge in Abelian gauge theory. We then study the chiral phase transition on temperature from the obtained solutions. We find that, within the quenched Schwinger-Dyson equations, there exists substantial gauge dependence on the solutions and the critical temperature.
|
1506.05487
|
Feng-Kun Guo
|
Feng-Kun Guo, Ulf-G. Mei{\ss}ner
|
Cumulants of the QCD topological charge distribution
|
match the version published in PLB
|
Phys. Lett. B 749: 278-282 (2015)
|
10.1016/j.physletb.2015.07.076
| null |
hep-ph hep-lat hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The distribution of the QCD topological charge can be described by cumulants,
with the lowest one being the topological susceptibility. The vacuum energy
density in a theta-vacuum is the generating function for these cumulants. In
this paper, we derive the vacuum energy density in SU(2) chiral perturbation
theory up to next-to-leading order keeping different up and down quark masses,
which can be used to calculate any cumulant of the topological charge
distribution. We also give the expression for the case of SU(N) with degenerate
quark masses. In this case, all cumulants depend on the same linear combination
of low-energy constants and chiral logarithm, and thus there are sum rules
between the N-flavor quark condensate and the cumulants free of next-to-leading
order corrections.
|
[
{
"created": "Wed, 17 Jun 2015 20:31:56 GMT",
"version": "v1"
},
{
"created": "Fri, 31 Jul 2015 10:29:26 GMT",
"version": "v2"
},
{
"created": "Mon, 17 Aug 2015 07:41:21 GMT",
"version": "v3"
}
] |
2015-08-20
|
[
[
"Guo",
"Feng-Kun",
""
],
[
"Meißner",
"Ulf-G.",
""
]
] |
The distribution of the QCD topological charge can be described by cumulants, with the lowest one being the topological susceptibility. The vacuum energy density in a theta-vacuum is the generating function for these cumulants. In this paper, we derive the vacuum energy density in SU(2) chiral perturbation theory up to next-to-leading order keeping different up and down quark masses, which can be used to calculate any cumulant of the topological charge distribution. We also give the expression for the case of SU(N) with degenerate quark masses. In this case, all cumulants depend on the same linear combination of low-energy constants and chiral logarithm, and thus there are sum rules between the N-flavor quark condensate and the cumulants free of next-to-leading order corrections.
|
hep-ph/9404253
|
Christopher Kolda
|
Chris Kolda, Leszek Roszkowski, James D. Wells, and G.L. Kane
|
Predictions for Constrained Minimal Supersymmetry with Bottom-Tau Mass
Unification
|
Michigan preprint UM-TH-94-03, LaTeX, 18 pages with inline figures
(figures included in uuencoded file). Complete PS file also available by
anonymous FTP to williams.physics.lsa.umich.edu in
/pub/preprints/UM-TH-94-03.ps.Z or by e-mailing request
|
Phys.Rev.D50:3498-3507,1994
|
10.1103/PhysRevD.50.3498
| null |
hep-ph
| null |
We examine the Constrained Minimal Supersymmetric Standard Model (CMSSM) with
an additional requirement of strict b - tau unification in the region of small
tan(beta). We find that the parameter space becomes completely limited below
about 1 TeV by physical constraints alone, without a fine-tuning constraint. We
study the resulting phenomenological consequences, and point out several ways
of falsifying the adopted b - tau unification assumption. We also comment on
the effect of a constraint from the non-observation of proton decay.
|
[
{
"created": "Mon, 11 Apr 1994 20:37:40 GMT",
"version": "v1"
}
] |
2011-01-27
|
[
[
"Kolda",
"Chris",
""
],
[
"Roszkowski",
"Leszek",
""
],
[
"Wells",
"James D.",
""
],
[
"Kane",
"G. L.",
""
]
] |
We examine the Constrained Minimal Supersymmetric Standard Model (CMSSM) with an additional requirement of strict b - tau unification in the region of small tan(beta). We find that the parameter space becomes completely limited below about 1 TeV by physical constraints alone, without a fine-tuning constraint. We study the resulting phenomenological consequences, and point out several ways of falsifying the adopted b - tau unification assumption. We also comment on the effect of a constraint from the non-observation of proton decay.
|
0808.1595
|
Pran Nath
|
Daniel Feldman, Zuowei Liu, and Pran Nath
|
Decoding the Mechanism for the Origin of Dark Matter in the Early
Universe Using LHC Data
|
7 pages, 5 figs, 2 columns, Accepted for publication in Physical
Review D
|
Phys.Rev.D78:083523,2008
|
10.1103/PhysRevD.78.083523
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
It is shown that LHC data can allow one to decode the mechanism by which dark
matter is generated in the early universe in supersymmetric theories. We focus
on two of the major mechanisms for such generation of dark matter which are
known to be the Stau Coannihilation (Stau-Co) where the neutralino is typically
Bino like and annihilation on the Hyperbolic Branch (HB) where the neutralino
has a significant Higgsino component. An investigation of how one may
discriminate between the Stau-Co region and the HB region using LHC data is
given for the mSUGRA model. The analysis utilizes several signatures including
multi leptons, hadronic jets, b-tagging, and missing transverse momentum. A
study of the SUSY signatures reveals several correlated smoking gun signals
allowing a clear discrimination between the Stau-Co and the HB regions where
dark matter in the early universe can originate.
|
[
{
"created": "Tue, 12 Aug 2008 19:50:27 GMT",
"version": "v1"
},
{
"created": "Thu, 18 Sep 2008 19:58:05 GMT",
"version": "v2"
}
] |
2008-11-26
|
[
[
"Feldman",
"Daniel",
""
],
[
"Liu",
"Zuowei",
""
],
[
"Nath",
"Pran",
""
]
] |
It is shown that LHC data can allow one to decode the mechanism by which dark matter is generated in the early universe in supersymmetric theories. We focus on two of the major mechanisms for such generation of dark matter which are known to be the Stau Coannihilation (Stau-Co) where the neutralino is typically Bino like and annihilation on the Hyperbolic Branch (HB) where the neutralino has a significant Higgsino component. An investigation of how one may discriminate between the Stau-Co region and the HB region using LHC data is given for the mSUGRA model. The analysis utilizes several signatures including multi leptons, hadronic jets, b-tagging, and missing transverse momentum. A study of the SUSY signatures reveals several correlated smoking gun signals allowing a clear discrimination between the Stau-Co and the HB regions where dark matter in the early universe can originate.
|
0911.2607
|
Christian Sander
|
Christian Autermann, Benedikt Mura, Christian Sander, Hannes
Schettler, Peter Schleper
|
Determination of supersymmetric masses using kinematic fits at the LHC
|
15 pages, 15 figures
| null | null | null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
In case of the discovery of supersymmetry at the LHC, the goal will be to
identify the underlying theory, its fundamental parameters, and the masses of
SUSY particles. We followed here the approach to reconstruct the decay chains
in SUSY events under the assumption of common intermediate masses. These masses
cannot be extracted from each event because of the unmeasured LSP momenta in
case of R-parity conservation. But an ensemble of events can be
over-constrained, if the decay chains are long enough, such that enough mass
constraints are available. Here, we present a new method combining a) a SUSY
mass scan, b) a kinematic fitting based on a genetic algorithm for decay chain
reconstruction, and c) the usage of angular decay information to suppress the
background from other SUSY processes. Taking into account the full
combinatorial background and experimental resolutions in the most difficult
case of the fully hadronic decay mode, we demonstrate, within one SUSY
scenario, that this method can be used to derive a probability map of the SUSY
parameter space.
|
[
{
"created": "Fri, 13 Nov 2009 14:00:05 GMT",
"version": "v1"
}
] |
2009-11-16
|
[
[
"Autermann",
"Christian",
""
],
[
"Mura",
"Benedikt",
""
],
[
"Sander",
"Christian",
""
],
[
"Schettler",
"Hannes",
""
],
[
"Schleper",
"Peter",
""
]
] |
In case of the discovery of supersymmetry at the LHC, the goal will be to identify the underlying theory, its fundamental parameters, and the masses of SUSY particles. We followed here the approach to reconstruct the decay chains in SUSY events under the assumption of common intermediate masses. These masses cannot be extracted from each event because of the unmeasured LSP momenta in case of R-parity conservation. But an ensemble of events can be over-constrained, if the decay chains are long enough, such that enough mass constraints are available. Here, we present a new method combining a) a SUSY mass scan, b) a kinematic fitting based on a genetic algorithm for decay chain reconstruction, and c) the usage of angular decay information to suppress the background from other SUSY processes. Taking into account the full combinatorial background and experimental resolutions in the most difficult case of the fully hadronic decay mode, we demonstrate, within one SUSY scenario, that this method can be used to derive a probability map of the SUSY parameter space.
|
hep-ph/9911455
|
Andrzej Czarnecki
|
Andrzej Czarnecki
|
Positronium properties
|
Talk given at the 39th Cracow School of Theoretical Physics,
Zakopane, Poland, May 1999; 11 pages, latex
|
Acta Phys.Polon.B30:3837-3847,1999
| null |
BNL-HET-99/38
|
hep-ph
| null |
This talk gives an elementary introduction to the basic properties of
positronium. Recent progress in theoretical studies of the hyperfine splitting
and lifetime of the ground state is reviewed. Sensitivity of these precisely
measured quantities to some New Physics effects is discussed.
|
[
{
"created": "Tue, 23 Nov 1999 20:17:45 GMT",
"version": "v1"
}
] |
2011-04-15
|
[
[
"Czarnecki",
"Andrzej",
""
]
] |
This talk gives an elementary introduction to the basic properties of positronium. Recent progress in theoretical studies of the hyperfine splitting and lifetime of the ground state is reviewed. Sensitivity of these precisely measured quantities to some New Physics effects is discussed.
|
1606.06679
|
Ernest Ma
|
Ernest Ma (UC Riverside)
|
Progressive Gauge U(1) Family Symmetry for Quarks and Leptons
|
9 pages, no figure
|
Phys. Rev. D 94, 031701 (2016)
|
10.1103/PhysRevD.94.031701
|
UCRHEP-T568 (June 2016)
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The pattern of quark and lepton mass matrices is unexplained in the standard
model of particle interactions. I propose the novel idea of a progressive gauge
U(1) symmetry where it is a reflection of the regressive electroweak symmetry
breaking pattern, caused by an extended Higgs scalar sector. Phenomenological
implications of this new hypothesis are discussed.
|
[
{
"created": "Tue, 21 Jun 2016 17:41:42 GMT",
"version": "v1"
}
] |
2016-08-10
|
[
[
"Ma",
"Ernest",
"",
"UC Riverside"
]
] |
The pattern of quark and lepton mass matrices is unexplained in the standard model of particle interactions. I propose the novel idea of a progressive gauge U(1) symmetry where it is a reflection of the regressive electroweak symmetry breaking pattern, caused by an extended Higgs scalar sector. Phenomenological implications of this new hypothesis are discussed.
|
2005.04127
|
Eugenio Megias
|
Eugenio Megias, Germano Nardini, Mariano Quiros
|
Gravitational Imprints from Heavy Kaluza-Klein Resonances
|
11 pages, 6 figures; v2 extended version: added references and Figs.
1 (right), 2, 3, 4 (lower panels) and 5, Sec. IV, and extended discussion in
Secs. V, VI and VII; v3 added references, extended discussion in Sec. VI. It
matches the version published in Physical Review D
|
Phys. Rev. D 102, 055004 (2020)
|
10.1103/PhysRevD.102.055004
| null |
hep-ph gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We systematically study the holographic phase transition of the radion field
in a five-dimensional warped model which includes a scalar potential with a
power-like behavior. We consider Kaluza-Klein (KK) resonances with masses
$m_{\rm KK}$ at the TeV scale or beyond. The backreaction of the radion field
on the gravitational metric is taken into account by using the superpotential
formalism. The confinement/deconfinement first order phase transition leads to
a gravitational wave stochastic background which mainly depends on the scale
$m_{\rm KK}$ and the number of colors, $N$, in the dual theory. Its power
spectrum peaks at a frequency that depends on the amount of tuning required in
the electroweak sector. It turns out that the present and forthcoming
gravitational wave observatories can probe scenarios where the KK resonances
are very heavy. Current aLIGO data already rule out vector boson KK resonances
with masses in the interval $m_{\rm KK}\sim(1 - 10) \times 10^5$ TeV. Future
gravitational experiments will be sensitive to resonances with masses $m_{\rm
KK}\lesssim 10^5$ TeV (LISA), $10^8$ TeV (aLIGO Design) and $10^9$ TeV (ET).
Finally, we also find that the Big Bang Nucleosynthesis bound in the frequency
spectrum turns into a lower bound for the nucleation temperature as $T_n
\gtrsim 10^{-4}\sqrt{N} \,m_{\rm KK}$.
|
[
{
"created": "Fri, 8 May 2020 16:08:21 GMT",
"version": "v1"
},
{
"created": "Sat, 30 May 2020 21:10:15 GMT",
"version": "v2"
},
{
"created": "Thu, 10 Sep 2020 19:50:33 GMT",
"version": "v3"
}
] |
2020-09-16
|
[
[
"Megias",
"Eugenio",
""
],
[
"Nardini",
"Germano",
""
],
[
"Quiros",
"Mariano",
""
]
] |
We systematically study the holographic phase transition of the radion field in a five-dimensional warped model which includes a scalar potential with a power-like behavior. We consider Kaluza-Klein (KK) resonances with masses $m_{\rm KK}$ at the TeV scale or beyond. The backreaction of the radion field on the gravitational metric is taken into account by using the superpotential formalism. The confinement/deconfinement first order phase transition leads to a gravitational wave stochastic background which mainly depends on the scale $m_{\rm KK}$ and the number of colors, $N$, in the dual theory. Its power spectrum peaks at a frequency that depends on the amount of tuning required in the electroweak sector. It turns out that the present and forthcoming gravitational wave observatories can probe scenarios where the KK resonances are very heavy. Current aLIGO data already rule out vector boson KK resonances with masses in the interval $m_{\rm KK}\sim(1 - 10) \times 10^5$ TeV. Future gravitational experiments will be sensitive to resonances with masses $m_{\rm KK}\lesssim 10^5$ TeV (LISA), $10^8$ TeV (aLIGO Design) and $10^9$ TeV (ET). Finally, we also find that the Big Bang Nucleosynthesis bound in the frequency spectrum turns into a lower bound for the nucleation temperature as $T_n \gtrsim 10^{-4}\sqrt{N} \,m_{\rm KK}$.
|
hep-ph/9503297
| null |
Dieter Zeppenfeld
|
GLUON RADIATION PATTERNS IN HARD SCATTERING EVENTS
|
5 pages, Latex file, 1 uuencoded postscript figure included.
Compressed postscript version including figure available at
ftp://phenom.physics.wisc.edu/pub/preprints/1995/madph-95-876.ps.Z or at
http://phenom.physics.wisc.edu/pub/preprints/1995/madph-95-876.ps.Z
| null | null |
MADPH-95-876
|
hep-ph
| null |
The radiation pattern of relatively soft gluons in hard scattering events is
sensitive to the underlying color structure. As an example I consider heavy
Higgs production via weak boson fusion at the LHC. A minijet veto, which makes
use of the different patterns for signal and backgrounds, provides an effective
Higgs search tool. Talk presented at the Conference on Physics {\it Beyond the
Standard Model IV}, Lake Tahoe, California, December 14--18, 1994.
|
[
{
"created": "Fri, 10 Mar 1995 22:25:21 GMT",
"version": "v1"
},
{
"created": "Tue, 14 Mar 1995 15:52:12 GMT",
"version": "v2"
}
] |
2016-09-01
|
[
[
"Zeppenfeld",
"Dieter",
""
]
] |
The radiation pattern of relatively soft gluons in hard scattering events is sensitive to the underlying color structure. As an example I consider heavy Higgs production via weak boson fusion at the LHC. A minijet veto, which makes use of the different patterns for signal and backgrounds, provides an effective Higgs search tool. Talk presented at the Conference on Physics {\it Beyond the Standard Model IV}, Lake Tahoe, California, December 14--18, 1994.
|
1202.1922
|
Eugene Levin
|
E Levin (Tel Aviv U., UTFSM) and I. Potashnikova (UTFSM)
|
N=4 SYM model for soft interactions at high energy
|
14 pp, 10 figures in,eps files
| null |
10.1007/JHEP07(2012)035
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
In this paper we compare the prediction for high energy soft interactions in
the model of N=4 SYM, with the experimental data. It is shown that this model
is able to describe the total, elastic and inelastic cross sections and the
elastic slope with only three free parameters. However, the model failed to
obtain the cross sections for diffractive production, which was close to the
experimental data, giving small values for them. We believe that the theory of
N=4 SYM, of the order of $1/\lambda$ is needed to find the origin of large mass
diffraction.
|
[
{
"created": "Thu, 9 Feb 2012 09:21:53 GMT",
"version": "v1"
},
{
"created": "Thu, 19 Apr 2012 20:49:37 GMT",
"version": "v2"
}
] |
2015-06-04
|
[
[
"Levin",
"E",
"",
"Tel Aviv U., UTFSM"
],
[
"Potashnikova",
"I.",
"",
"UTFSM"
]
] |
In this paper we compare the prediction for high energy soft interactions in the model of N=4 SYM, with the experimental data. It is shown that this model is able to describe the total, elastic and inelastic cross sections and the elastic slope with only three free parameters. However, the model failed to obtain the cross sections for diffractive production, which was close to the experimental data, giving small values for them. We believe that the theory of N=4 SYM, of the order of $1/\lambda$ is needed to find the origin of large mass diffraction.
|
1208.0536
|
Florian Preis
|
Florian Preis, Anton Rebhan and Andreas Schmitt
|
Inverse magnetic catalysis in field theory and gauge-gravity duality
|
37 pages, 11 figures, to appear in Lect. Notes Phys. "Strongly
interacting matter in magnetic fields" (Springer), edited by D. Kharzeev, K.
Landsteiner, A. Schmitt, H.-U. Yee
| null |
10.1007/978-3-642-37305-3_3
| null |
hep-ph hep-th nucl-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We investigate the surface of the chiral phase transition in the
three-dimensional parameter space of temperature, baryon chemical potential and
magnetic field in two different approaches, the field-theoretical
Nambu-Jona-Lasinio (NJL) model and the holographic Sakai-Sugimoto model. The
latter is a top-down approach to a gravity dual of QCD with an asymptotically
large number of colors and becomes, in a certain limit, dual to an NJL-like
model. Our main observation is that, at nonzero chemical potential, a magnetic
field can restore chiral symmetry, in apparent contrast to the phenomenon of
magnetic catalysis. This "inverse magnetic catalysis" occurs in the
Sakai-Sugimoto model and, for sufficiently large coupling, in the NJL model and
is related to the physics of the lowest Landau level. While in most parts our
discussion is a pedagogical review of previously published results, we include
new analytical results for the NJL approach and a thorough comparison of
inverse magnetic catalysis in the two approaches.
|
[
{
"created": "Thu, 2 Aug 2012 16:41:08 GMT",
"version": "v1"
}
] |
2015-06-11
|
[
[
"Preis",
"Florian",
""
],
[
"Rebhan",
"Anton",
""
],
[
"Schmitt",
"Andreas",
""
]
] |
We investigate the surface of the chiral phase transition in the three-dimensional parameter space of temperature, baryon chemical potential and magnetic field in two different approaches, the field-theoretical Nambu-Jona-Lasinio (NJL) model and the holographic Sakai-Sugimoto model. The latter is a top-down approach to a gravity dual of QCD with an asymptotically large number of colors and becomes, in a certain limit, dual to an NJL-like model. Our main observation is that, at nonzero chemical potential, a magnetic field can restore chiral symmetry, in apparent contrast to the phenomenon of magnetic catalysis. This "inverse magnetic catalysis" occurs in the Sakai-Sugimoto model and, for sufficiently large coupling, in the NJL model and is related to the physics of the lowest Landau level. While in most parts our discussion is a pedagogical review of previously published results, we include new analytical results for the NJL approach and a thorough comparison of inverse magnetic catalysis in the two approaches.
|
hep-ph/9802326
| null |
Fayyazuddin, Riazuddin
|
Two body non-leptonic $\Lambda_b$ decays in quark model with
factorization ansatz
|
18 pages, latex, 1 figure available on request, please send any
questions or comments to riazs@dpc.kfupm.edu.sa
|
Phys.Rev. D58 (1998) 014016
|
10.1103/PhysRevD.58.014016
|
QAU-98
|
hep-ph
| null |
The two body non-leptonic $\Lambda_b$ decays are analyzed in factorization
approximation, using quark model, $\xi = 1 / N_c$ as a free parameter. It is
shown that the experimental branching ratio for $\Lambda_b \longrightarrow
\Lambda {J/\psi}$ restricts $\xi$ and this ratio can be understood for a value
of $\xi$ which lies in the range $ 0 \leq \xi \leq 0.5 $ suggested by two body
B meson decays. The branching ratios for $\Lambda_b \longrightarrow \Lambda_{c}
D^*_s(D_s) $ are predicted to be larger than the previous estimates. Finally it
is pointed that CKM-Wolfenstein parameter $\rho^2 + \eta^2$, where $\eta$ is CP
phase, can be determined from the ratio of widths of $\Lambda_b \longrightarrow
\Lambda \bar{D}$ and $\Lambda_b \longrightarrow \Lambda {J/\psi}$ or that of
$\Lambda_b \longrightarrow p D_s$ and $\Lambda_b \longrightarrow \Lambda_c D_s$
independent of the parameter $\xi$.
|
[
{
"created": "Sun, 15 Feb 1998 19:48:39 GMT",
"version": "v1"
}
] |
2019-08-17
|
[
[
"Fayyazuddin",
"",
""
],
[
"Riazuddin",
"",
""
]
] |
The two body non-leptonic $\Lambda_b$ decays are analyzed in factorization approximation, using quark model, $\xi = 1 / N_c$ as a free parameter. It is shown that the experimental branching ratio for $\Lambda_b \longrightarrow \Lambda {J/\psi}$ restricts $\xi$ and this ratio can be understood for a value of $\xi$ which lies in the range $ 0 \leq \xi \leq 0.5 $ suggested by two body B meson decays. The branching ratios for $\Lambda_b \longrightarrow \Lambda_{c} D^*_s(D_s) $ are predicted to be larger than the previous estimates. Finally it is pointed that CKM-Wolfenstein parameter $\rho^2 + \eta^2$, where $\eta$ is CP phase, can be determined from the ratio of widths of $\Lambda_b \longrightarrow \Lambda \bar{D}$ and $\Lambda_b \longrightarrow \Lambda {J/\psi}$ or that of $\Lambda_b \longrightarrow p D_s$ and $\Lambda_b \longrightarrow \Lambda_c D_s$ independent of the parameter $\xi$.
|
2004.04505
|
Neda Darvishi
|
Neda Darvishi and Apostolos Pilaftsis
|
Natural Alignment in Multi-Higgs Doublet Models
|
CORFU2019 Proceeding, 21 pages, 6 figures and 2 tables
| null | null | null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We present the complete set of continuous maximal symmetries that the
potential of an $n$-Higgs Doublet Model ($n$HDM) should satisfy for natural
Standard Model (SM) alignment. As a result, no large mass scales or fine-tuning
is required for such alignment, which still persists even if these symmetries
were broken softly by bilinear mass terms. In particular, the Maximal Symmetric
$n$HDM (MS-$n$HDM) can provide both natural SM alignment and quartic coupling
unification up to the Planck scale. Most remarkably, we show that the MS-2HDM
is a very predictive extension of the SM governed by two only additional
parameters: (i) the charged Higgs mass $M_{h^{\pm}}$ (or $m^2_{12}$) and (ii)
$\tan\beta$, whilst the quartic coupling unification scale $\mu_X$ is predicted
to assume two discrete values. With these two input parameters, the entire
Higgs-mass spectrum of the model can be determined. Moreover, we obtain
definite predictions of misalignment for the SM-like Higgs-boson couplings to
the gauge bosons and to the quarks, which might be testable at future precision
high-energy colliders.
|
[
{
"created": "Thu, 9 Apr 2020 12:05:13 GMT",
"version": "v1"
}
] |
2020-04-10
|
[
[
"Darvishi",
"Neda",
""
],
[
"Pilaftsis",
"Apostolos",
""
]
] |
We present the complete set of continuous maximal symmetries that the potential of an $n$-Higgs Doublet Model ($n$HDM) should satisfy for natural Standard Model (SM) alignment. As a result, no large mass scales or fine-tuning is required for such alignment, which still persists even if these symmetries were broken softly by bilinear mass terms. In particular, the Maximal Symmetric $n$HDM (MS-$n$HDM) can provide both natural SM alignment and quartic coupling unification up to the Planck scale. Most remarkably, we show that the MS-2HDM is a very predictive extension of the SM governed by two only additional parameters: (i) the charged Higgs mass $M_{h^{\pm}}$ (or $m^2_{12}$) and (ii) $\tan\beta$, whilst the quartic coupling unification scale $\mu_X$ is predicted to assume two discrete values. With these two input parameters, the entire Higgs-mass spectrum of the model can be determined. Moreover, we obtain definite predictions of misalignment for the SM-like Higgs-boson couplings to the gauge bosons and to the quarks, which might be testable at future precision high-energy colliders.
|
1803.07045
|
Thomas Becher
|
Marcel Balsiger, Thomas Becher, Ding Yu Shao
|
Non-global logarithms in jet and isolation cone cross sections
|
39 pages, 13 figures. v2: journal version with new result (4.18) for
narrow isolation cones
| null |
10.1007/JHEP08(2018)104
|
CERN-TH-2018-187
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Starting from a factorization theorem in effective field theory, we derive a
parton-shower equation for the resummation of non-global logarithms. We have
implemented this shower and interfaced it with a tree-level event generator to
obtain an automated framework to resum the leading logarithm of non-global
observables in the large-$N_c$ limit. Using this setup, we compute gap
fractions for dijet processes and isolation cone cross sections relevant for
photon production. We compare our results with fixed-order computations and LHC
measurements. We find that naive exponentiation is often not adequate,
especially when the vetoed region is small, since non-global contributions are
enhanced due to their dependence on the veto-region size. Since our parton
shower is derived from first principles and based on renormalization-group
evolution, it is clear what ingredients will have to be included to perform
resummations at subleading logarithmic accuracy in the future.
|
[
{
"created": "Mon, 19 Mar 2018 17:18:24 GMT",
"version": "v1"
},
{
"created": "Wed, 15 Aug 2018 12:02:17 GMT",
"version": "v2"
}
] |
2018-09-26
|
[
[
"Balsiger",
"Marcel",
""
],
[
"Becher",
"Thomas",
""
],
[
"Shao",
"Ding Yu",
""
]
] |
Starting from a factorization theorem in effective field theory, we derive a parton-shower equation for the resummation of non-global logarithms. We have implemented this shower and interfaced it with a tree-level event generator to obtain an automated framework to resum the leading logarithm of non-global observables in the large-$N_c$ limit. Using this setup, we compute gap fractions for dijet processes and isolation cone cross sections relevant for photon production. We compare our results with fixed-order computations and LHC measurements. We find that naive exponentiation is often not adequate, especially when the vetoed region is small, since non-global contributions are enhanced due to their dependence on the veto-region size. Since our parton shower is derived from first principles and based on renormalization-group evolution, it is clear what ingredients will have to be included to perform resummations at subleading logarithmic accuracy in the future.
|
hep-ph/9701241
|
Robert Thorne
|
R.S. Thorne
|
A Complete Leading-Order, Renormalization-Scheme-Consistent Calculation
of Small--x Structure functions, Including Leading-ln(1/x) Terms
|
106 pages, 4 figures as ps files, includes a variation of harmac.
Corrections to some typos in references, and form of some references changed,
in particular hep-ph(ex) numbers included for papers not yet published. No
changes to body of text
| null | null |
RAL-96-065
|
hep-ph
| null |
We present calculations of the structure functions F_2(x,Q^2) and F_L(x,Q^2),
concentrating on small x. After discussing the standard expansion of the
structure functions in powers of \alpha_s(Q^2) we consider a leading-order
expansion in ln(1/x) and finally an expansion which is leading order in both
ln(1/x) and \alpha_s(Q^2), and which we argue is the only really correct
expansion scheme. Ordering the calculation in a renormalization-scheme-
consistent manner, there is no factorization scheme dependence, as there should
not be in calculations of physical quantities. The calculational method
naturally leads to the ``physical anomalous dimensions'' of Catani, but imposes
stronger constraints than just the use of these effective anomalous dimensions.
In particular, a relationship between the small-x forms of the inputs
F_2(x,Q_0^2) and F_L(x,Q_0^2) is predicted. Analysis of a wide range of data
for F_2(x,Q^2) is performed, and a very good global fit obtained, particularly
for data at small x. The fit allows a prediction for F_L(x,Q^2) to be produced,
which is smaller than those produced by the usual NLO-in-\alpha_s(Q^2) fits to
F_2(x,Q^2) and different in shape.
|
[
{
"created": "Tue, 7 Jan 1997 17:28:57 GMT",
"version": "v1"
},
{
"created": "Wed, 8 Jan 1997 17:32:52 GMT",
"version": "v2"
}
] |
2008-02-03
|
[
[
"Thorne",
"R. S.",
""
]
] |
We present calculations of the structure functions F_2(x,Q^2) and F_L(x,Q^2), concentrating on small x. After discussing the standard expansion of the structure functions in powers of \alpha_s(Q^2) we consider a leading-order expansion in ln(1/x) and finally an expansion which is leading order in both ln(1/x) and \alpha_s(Q^2), and which we argue is the only really correct expansion scheme. Ordering the calculation in a renormalization-scheme- consistent manner, there is no factorization scheme dependence, as there should not be in calculations of physical quantities. The calculational method naturally leads to the ``physical anomalous dimensions'' of Catani, but imposes stronger constraints than just the use of these effective anomalous dimensions. In particular, a relationship between the small-x forms of the inputs F_2(x,Q_0^2) and F_L(x,Q_0^2) is predicted. Analysis of a wide range of data for F_2(x,Q^2) is performed, and a very good global fit obtained, particularly for data at small x. The fit allows a prediction for F_L(x,Q^2) to be produced, which is smaller than those produced by the usual NLO-in-\alpha_s(Q^2) fits to F_2(x,Q^2) and different in shape.
|
1709.03797
|
Oliver Fischer Dr.
|
Stefan Antusch, Eros Cazzato, Oliver Fischer
|
Resolvable heavy neutrino-antineutrino oscillations at colliders
|
6 pages + references, 3 figures, matches published version
| null | null | null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Heavy neutrino-antineutrino oscillations can naturally appear in mechanisms
of low scale neutrino mass generation, where pairs of heavy neutrinos have
almost degenerate masses. We discuss the case where the heavy neutrinos are
sufficiently long-lived to decay displaced from the primary vertex, such that
the oscillations of the heavy neutrinos into antineutrinos can potentially be
observed at the (high-luminosity) LHC and at currently planned future collider
experiments. The observation of these oscillations would have far-reaching
consequences: it would, for instance, prove the existence of lepton number
violation and the Majorana nature of neutrino masses, and it would allow a deep
insight into the nature of the neutrino mass generation mechanism.
|
[
{
"created": "Tue, 12 Sep 2017 12:17:37 GMT",
"version": "v1"
},
{
"created": "Tue, 12 Mar 2019 09:29:07 GMT",
"version": "v2"
}
] |
2019-03-13
|
[
[
"Antusch",
"Stefan",
""
],
[
"Cazzato",
"Eros",
""
],
[
"Fischer",
"Oliver",
""
]
] |
Heavy neutrino-antineutrino oscillations can naturally appear in mechanisms of low scale neutrino mass generation, where pairs of heavy neutrinos have almost degenerate masses. We discuss the case where the heavy neutrinos are sufficiently long-lived to decay displaced from the primary vertex, such that the oscillations of the heavy neutrinos into antineutrinos can potentially be observed at the (high-luminosity) LHC and at currently planned future collider experiments. The observation of these oscillations would have far-reaching consequences: it would, for instance, prove the existence of lepton number violation and the Majorana nature of neutrino masses, and it would allow a deep insight into the nature of the neutrino mass generation mechanism.
|
hep-ph/0204003
|
Lianshou Liu
|
Liu Lianshou
|
On the Phase Space Partition in High Energy Collisions
|
4 pages, 6 figures
| null | null | null |
hep-ph
| null |
In high energy hadron-hadron and e+e- collisions, to isolate a part of the
phase space in multi-hadron final states is necessary for exploring the
underlying dynamics. It is shown that the partition of phase space according to
the value of rapidity, popularly used in hadron-hadron collisions, is
inappropriate for the study of e+e- collisions. The proper way in the latter
case is to identify the visible jets and take them as objects for detailed
study, forming an extended phase space. The value y_cut^(0) of the
distance-measure for the identification of visible jets is determined. A new
variable $r$ is introduced to further partition the phase space inside jets,
which possesses a very good anomalous scaling property, showing that the
$r$-distribution inside jets is a self-similar fractal.
|
[
{
"created": "Sat, 30 Mar 2002 02:19:23 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Lianshou",
"Liu",
""
]
] |
In high energy hadron-hadron and e+e- collisions, to isolate a part of the phase space in multi-hadron final states is necessary for exploring the underlying dynamics. It is shown that the partition of phase space according to the value of rapidity, popularly used in hadron-hadron collisions, is inappropriate for the study of e+e- collisions. The proper way in the latter case is to identify the visible jets and take them as objects for detailed study, forming an extended phase space. The value y_cut^(0) of the distance-measure for the identification of visible jets is determined. A new variable $r$ is introduced to further partition the phase space inside jets, which possesses a very good anomalous scaling property, showing that the $r$-distribution inside jets is a self-similar fractal.
|
hep-ph/0404187
|
Sin Kyu Kang
|
Sanghyeon Chang, Sin Kyu Kang, Kim Siyeon
|
Minimal seesaw model with tri/bi-maximal mixing and leptogenesis
|
10 pages, 4 figures, revtex4, version to appear in Phys. Lett. B
|
Phys.Lett.B597:78-88,2004
|
10.1016/j.physletb.2004.06.104
| null |
hep-ph
| null |
We examine minimal seesaw mechanism in which the masses of light neutrinos
are described with tri/bi-maximal mixing in the basis where the charged-lepton
Yukawa matrix and heavy Majorana neutrino mass matrix are diagonal. We search
for all possible Dirac mass textures which contain at least one zero entry in
$3 \times 2$ matrix and evaluate the corresponding lepton asymmetries. We
present the baryon asymmetry in terms of a single low energy unknown, a
Majorana CP phase to be clued from neutrinoless double beta decay.
|
[
{
"created": "Wed, 21 Apr 2004 22:51:43 GMT",
"version": "v1"
},
{
"created": "Mon, 26 Jul 2004 03:18:52 GMT",
"version": "v2"
}
] |
2014-11-17
|
[
[
"Chang",
"Sanghyeon",
""
],
[
"Kang",
"Sin Kyu",
""
],
[
"Siyeon",
"Kim",
""
]
] |
We examine minimal seesaw mechanism in which the masses of light neutrinos are described with tri/bi-maximal mixing in the basis where the charged-lepton Yukawa matrix and heavy Majorana neutrino mass matrix are diagonal. We search for all possible Dirac mass textures which contain at least one zero entry in $3 \times 2$ matrix and evaluate the corresponding lepton asymmetries. We present the baryon asymmetry in terms of a single low energy unknown, a Majorana CP phase to be clued from neutrinoless double beta decay.
|
hep-ph/9505305
|
Mariana Kirchbach
|
R. Dahm (University Mainz, Germany) and M. Kirchbach (TH Darmstadt,
Germany)
|
Linear Wave Equations and Effective Lagrangians for Wigner
Supermultiplets
|
16 pages, LaTex
|
Int.J.Mod.Phys.A10:4225-4240,1995
|
10.1142/S0217751X95001960
|
MKPH-T-94-14
|
hep-ph
| null |
The relevance of the contracted SU(4) group as a symmetry group of the pion
nucleon scattering amplitudes in the large $N_c$ limit of QCD raises the
problem on the construction of effective Lagrangians for SU(4) supermultiplets.
In the present study we suggest effective Lagrangians for selfconjugate
representations of SU(4) in exploiting isomorphism between so(6) and ist
universal covering su(4). The model can be viewed as an extension of the linear
$\sigma$ model with SO(6) symmetry in place of SO(4) and generalizes the
concept of the linear wave equations for particles with arbitrary spin. We show
that the vector representation of SU(4) reduces on the SO(4) level to a
complexified quaternion. Its real part gives rise to the standard linear
$\sigma$ model with a hedgehog configuration for the pion field, whereas the
imaginary part describes vector meson degrees of freedom via purely transversal
$\rho$ mesons for which a helical field configuration is predicted. As a
minimal model, baryonic states are suggested to appear as solitons of that
quaternion.
|
[
{
"created": "Mon, 15 May 1995 13:35:27 GMT",
"version": "v1"
}
] |
2011-08-17
|
[
[
"Dahm",
"R.",
"",
"University Mainz, Germany"
],
[
"Kirchbach",
"M.",
"",
"TH Darmstadt,\n Germany"
]
] |
The relevance of the contracted SU(4) group as a symmetry group of the pion nucleon scattering amplitudes in the large $N_c$ limit of QCD raises the problem on the construction of effective Lagrangians for SU(4) supermultiplets. In the present study we suggest effective Lagrangians for selfconjugate representations of SU(4) in exploiting isomorphism between so(6) and ist universal covering su(4). The model can be viewed as an extension of the linear $\sigma$ model with SO(6) symmetry in place of SO(4) and generalizes the concept of the linear wave equations for particles with arbitrary spin. We show that the vector representation of SU(4) reduces on the SO(4) level to a complexified quaternion. Its real part gives rise to the standard linear $\sigma$ model with a hedgehog configuration for the pion field, whereas the imaginary part describes vector meson degrees of freedom via purely transversal $\rho$ mesons for which a helical field configuration is predicted. As a minimal model, baryonic states are suggested to appear as solitons of that quaternion.
|
hep-ph/0207020
|
Thomas Gehrmann
|
T.Gehrmann, E. Remiddi
|
Analytic Continuation of Massless Two-Loop Four-Point Functions
|
26 pages, LaTeX
|
Nucl.Phys. B640 (2002) 379-411
|
10.1016/S0550-3213(02)00569-2
|
CERN-TH/2002-145
|
hep-ph
| null |
We describe the analytic continuation of two-loop four-point functions with
one off-shell external leg and internal massless propagators from the Euclidean
region of space-like $1\to 3$ decay to Minkowskian regions relevant to all
$1\to 3$ and $2\to 2$ reactions with one space-like or time-like off-shell
external leg. Our results can be used to derive two-loop master integrals and
unrenormalized matrix elements for hadronic vector-boson-plus-jet production
and deep inelastic two-plus-one-jet production, from results previously
obtained for three-jet production in electron--positron annihilation.
|
[
{
"created": "Mon, 1 Jul 2002 13:39:15 GMT",
"version": "v1"
}
] |
2010-04-05
|
[
[
"Gehrmann",
"T.",
""
],
[
"Remiddi",
"E.",
""
]
] |
We describe the analytic continuation of two-loop four-point functions with one off-shell external leg and internal massless propagators from the Euclidean region of space-like $1\to 3$ decay to Minkowskian regions relevant to all $1\to 3$ and $2\to 2$ reactions with one space-like or time-like off-shell external leg. Our results can be used to derive two-loop master integrals and unrenormalized matrix elements for hadronic vector-boson-plus-jet production and deep inelastic two-plus-one-jet production, from results previously obtained for three-jet production in electron--positron annihilation.
|
1308.3655
|
Oscar Zapata
|
Diego Restrepo, Oscar Zapata, Carlos Yaguna
|
Models with radiative neutrino masses and viable dark matter candidates
|
37 pages, 5 figures; v2: discussions extended, references added,
matches the published version
| null |
10.1007/JHEP11(2013)011
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We provide a list of particle physics models at the TeV-scale that are
compatible with neutrino masses and dark matter. In these models, the Standard
Model particle content is extended with a small number (\leq 4) of scalar and
fermion fields transforming as singlets, doublets or triplets under SU(2), and
neutrino masses are generated radiatively via 1-loop diagrams. The dark matter
candidates are stabilized by a Z_2 symmetry and are in general mixtures of the
neutral components of such new multiplets. We describe the particle content of
each of these models and determine the conditions under which they are
consistent with current data. We find a total of 35 viable models, most of
which have not been previously studied in the literature. There is a great
potential to test these models at the LHC not only due to the TeV-scale masses
of the new fields but also because about half of the viable models contain
particles with exotic electric charges, which give rise to background-free
signals. Our results should serve as a first step for detailed analysis of
models that can simultaneously account for dark matter and neutrino masses.
|
[
{
"created": "Fri, 16 Aug 2013 15:37:12 GMT",
"version": "v1"
},
{
"created": "Fri, 11 Oct 2013 15:29:05 GMT",
"version": "v2"
}
] |
2015-06-16
|
[
[
"Restrepo",
"Diego",
""
],
[
"Zapata",
"Oscar",
""
],
[
"Yaguna",
"Carlos",
""
]
] |
We provide a list of particle physics models at the TeV-scale that are compatible with neutrino masses and dark matter. In these models, the Standard Model particle content is extended with a small number (\leq 4) of scalar and fermion fields transforming as singlets, doublets or triplets under SU(2), and neutrino masses are generated radiatively via 1-loop diagrams. The dark matter candidates are stabilized by a Z_2 symmetry and are in general mixtures of the neutral components of such new multiplets. We describe the particle content of each of these models and determine the conditions under which they are consistent with current data. We find a total of 35 viable models, most of which have not been previously studied in the literature. There is a great potential to test these models at the LHC not only due to the TeV-scale masses of the new fields but also because about half of the viable models contain particles with exotic electric charges, which give rise to background-free signals. Our results should serve as a first step for detailed analysis of models that can simultaneously account for dark matter and neutrino masses.
|
2111.10894
|
Ian Newsome
|
Ian M. Newsome
|
Validity of the Semiclassical Approximation in 1+1 Electrodynamics:
Numerical Solutions to the Linear Response Equation
|
13 pages, 3 figures, 16th Marcel Grossman Meeting Conference
Proceedings
| null | null | null |
hep-ph gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
From previous work arXiv:2010.09811, the semiclassical backreaction equation
in 1+1 dimensions was solved and a criterion was implemented to assess the
validity of the semiclassical approximation in this case. The criterion
involves the behavior of solutions to the linear response equation which
describes perturbations about solutions to the semiclassical backreaction
equation. The linear response equation involves a time integral over a
two-point correlation function for the current induced by the quantum field and
it is expected that significant growth in this two-point function (and
therefore in quantum fluctuations) will result in significant growth in
solutions to the linear response equation. It was conjectured for early times
that the difference of two nearby solutions to the semiclassical backreaction
equation, with similar initial conditions, can act as an approximate solution
to the linear response equation. A comparative analysis between the approximate
and numerical solutions to the linear response equation, for the critical scale
for particle production, will be presented for the case of a massive, quantized
spin 1/2 field in order to determine how robust the approximation method is for
representing its solutions.
|
[
{
"created": "Sun, 21 Nov 2021 20:32:48 GMT",
"version": "v1"
}
] |
2021-11-23
|
[
[
"Newsome",
"Ian M.",
""
]
] |
From previous work arXiv:2010.09811, the semiclassical backreaction equation in 1+1 dimensions was solved and a criterion was implemented to assess the validity of the semiclassical approximation in this case. The criterion involves the behavior of solutions to the linear response equation which describes perturbations about solutions to the semiclassical backreaction equation. The linear response equation involves a time integral over a two-point correlation function for the current induced by the quantum field and it is expected that significant growth in this two-point function (and therefore in quantum fluctuations) will result in significant growth in solutions to the linear response equation. It was conjectured for early times that the difference of two nearby solutions to the semiclassical backreaction equation, with similar initial conditions, can act as an approximate solution to the linear response equation. A comparative analysis between the approximate and numerical solutions to the linear response equation, for the critical scale for particle production, will be presented for the case of a massive, quantized spin 1/2 field in order to determine how robust the approximation method is for representing its solutions.
|
hep-ph/9807357
|
Kresimir Kumericki
|
D. Klabucar, K. Kumericki, B. Melic and I. Picek
|
On the instanton-induced portion of the nucleon strangeness
|
11 pages, 3 ps figures included, plain LaTeX2e, revised version to
appear in Eur. Phys. J. C, several points clarified and references added,
results compared to recent experiments at TJNAF (HAPPEX)
|
Eur.Phys.J.C9:589-599,1999
|
10.1007/s100529900056
|
ZTF-98/01
|
hep-ph nucl-th
| null |
We calculate the instanton contribution to the proton strangeness in the MIT
bag enriched by the presence of a dilute instanton liquid. The evaluation is
based on expressing the nucleon matrix elements of bilinear strange quark
operators in terms of a model valence nucleon state and interactions producing
quark-antiquark fluctuations on top of that valence state. Our method combines
the usage of the evolution operator containing a strangeness source, and the
Feynman-Hellmann theorem. It enables one to evaluate the strangeness in
different Lorentz channels in, essentially, the same way. Only the scalar
channel is found to be affected by the interaction induced by the random
instanton liquid.
|
[
{
"created": "Mon, 13 Jul 1998 13:54:34 GMT",
"version": "v1"
},
{
"created": "Mon, 10 May 1999 15:31:56 GMT",
"version": "v2"
}
] |
2011-09-13
|
[
[
"Klabucar",
"D.",
""
],
[
"Kumericki",
"K.",
""
],
[
"Melic",
"B.",
""
],
[
"Picek",
"I.",
""
]
] |
We calculate the instanton contribution to the proton strangeness in the MIT bag enriched by the presence of a dilute instanton liquid. The evaluation is based on expressing the nucleon matrix elements of bilinear strange quark operators in terms of a model valence nucleon state and interactions producing quark-antiquark fluctuations on top of that valence state. Our method combines the usage of the evolution operator containing a strangeness source, and the Feynman-Hellmann theorem. It enables one to evaluate the strangeness in different Lorentz channels in, essentially, the same way. Only the scalar channel is found to be affected by the interaction induced by the random instanton liquid.
|
hep-ph/0611389
|
Alessandro Strumia
|
Sacha Davidson, Gino Isidori, Alessandro Strumia
|
The smallest neutrino mass
|
6 pages. v2: final version to appear on PLB; important reference
added
|
Phys.Lett.B646:100-104,2007
|
10.1016/j.physletb.2007.01.015
|
IFUP-TH/06-23
|
hep-ph
| null |
We consider models where one Majorana neutrino is massless at tree level
(like the see saw with two right-handed neutrinos), and compute the
contribution to its mass m generated by two-loop quantum corrections. The
result is m \sim 10^{-13}eV in the SM and m \sim 10^{-10} eV (tanBeta/10)^4 in
the MSSM, compatible with the restricted range suggested by Affleck-Dine
baryogenesis.
|
[
{
"created": "Thu, 30 Nov 2006 17:29:32 GMT",
"version": "v1"
},
{
"created": "Wed, 17 Jan 2007 07:53:06 GMT",
"version": "v2"
}
] |
2008-11-26
|
[
[
"Davidson",
"Sacha",
""
],
[
"Isidori",
"Gino",
""
],
[
"Strumia",
"Alessandro",
""
]
] |
We consider models where one Majorana neutrino is massless at tree level (like the see saw with two right-handed neutrinos), and compute the contribution to its mass m generated by two-loop quantum corrections. The result is m \sim 10^{-13}eV in the SM and m \sim 10^{-10} eV (tanBeta/10)^4 in the MSSM, compatible with the restricted range suggested by Affleck-Dine baryogenesis.
|
1907.02861
|
Hidekazu Tanaka
|
Hidekazu Tanaka and Shuji Sasagawa
|
Quarks mass function at finite density in real-time formalism
|
11 pages, 5 figures. Some statements and Eq.(2.15) in the previous
version are modified
|
Prog Theor Exp Phys (2020)
|
10.1093/ptep/ptaa053
|
RUP-19-16
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Chiral symmetry restoration of quarks is investigated at finite density in
quantum chromodynamics. The effective quark mass is calculated with the
Schwinger-Dyson equation in the real-time formalism without the instantaneous
exchange approximation. We present some properties of the quark mass functions
and the quark propagator at zero temperature.
|
[
{
"created": "Tue, 25 Jun 2019 04:36:27 GMT",
"version": "v1"
},
{
"created": "Tue, 9 Jul 2019 06:32:28 GMT",
"version": "v2"
},
{
"created": "Mon, 7 Oct 2019 07:19:59 GMT",
"version": "v3"
},
{
"created": "Thu, 5 Dec 2019 05:28:32 GMT",
"version": "v4"
}
] |
2020-06-03
|
[
[
"Tanaka",
"Hidekazu",
""
],
[
"Sasagawa",
"Shuji",
""
]
] |
Chiral symmetry restoration of quarks is investigated at finite density in quantum chromodynamics. The effective quark mass is calculated with the Schwinger-Dyson equation in the real-time formalism without the instantaneous exchange approximation. We present some properties of the quark mass functions and the quark propagator at zero temperature.
|
1807.02068
|
Andreas Crivellin
|
Andreas Crivellin, Christoph Greub, Dario M\"uller and Francesco
Saturnino
|
Importance of Loop Effects in Explaining the Accumulated Evidence for
New Physics in B Decays with a Vector Leptoquark
|
8 pages, 4 figures, matches version accepted for publication in PRL
|
Phys. Rev. Lett. 122, 011805 (2019)
|
10.1103/PhysRevLett.122.011805
|
PSI-PR-18-07, ZU-TH 23/18
|
hep-ph hep-ex
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
In recent years experiments revealed intriguing hints for new physics (NP) in
$B$ decays involving \bctaunu and $b\to s\ell^+\ell^-$ transitions at the
$4\,\sigma$ and $5\,\sigma$ level, respectively. In addition, there are slight
disagreements in $b\to u \tau\nu$ and $b\to d\mu^+\mu^-$ observables. While not
significant on their own, they point in the same direction. Furthermore,
$V_{us}$ extracted from $\tau$ decays shows a slight tension
($\approx2.5\,\sigma$) with its value determined from CKM unitarity.
Additionally, BELLE found hints for an excess in $B_d\to\tau^+\tau^-$.
Concerning NP explanations, the vector leptoquark $SU(2)$ singlet is of special
interest since it is the only single particle extension of the SM which can (in
principle) address all the anomalies described above. For this purpose, large
couplings to $\tau$ leptons are necessary and loop effects, which we calculate
in this article, become important. Including them in our phenomenological
analysis, we find that neither the tension in $V_{us}$ nor the excess in
$B_d\to\tau^+\tau^-$ can be fully explained without violating bounds from
$K\to\pi\nu\bar\nu$. However, one can account for $b\to c\tau\nu$ and $b\to
u\tau\nu$ data finding intriguing correlations with $B_{q}\to\tau^+\tau^-$ and
$K\to \pi\nu\bar\nu$. Furthermore, the explanation of $b\to c\tau\nu$ predicts
a positive shift in $C_7$ and a negative one in $C_9$, being nicely in
agreement with the global fit to $b\to s\ell^+\ell^-$ data. Finally, we point
out that one can fully account for \bctaunu and $b\to s\ell^+\ell^-$ without
violating bounds from $\tau\to \phi\mu$, $\Upsilon\to\tau\mu$ or $b\to
s\tau\mu$ processes.
|
[
{
"created": "Thu, 5 Jul 2018 15:59:57 GMT",
"version": "v1"
},
{
"created": "Fri, 8 Feb 2019 10:37:55 GMT",
"version": "v2"
}
] |
2019-02-11
|
[
[
"Crivellin",
"Andreas",
""
],
[
"Greub",
"Christoph",
""
],
[
"Müller",
"Dario",
""
],
[
"Saturnino",
"Francesco",
""
]
] |
In recent years experiments revealed intriguing hints for new physics (NP) in $B$ decays involving \bctaunu and $b\to s\ell^+\ell^-$ transitions at the $4\,\sigma$ and $5\,\sigma$ level, respectively. In addition, there are slight disagreements in $b\to u \tau\nu$ and $b\to d\mu^+\mu^-$ observables. While not significant on their own, they point in the same direction. Furthermore, $V_{us}$ extracted from $\tau$ decays shows a slight tension ($\approx2.5\,\sigma$) with its value determined from CKM unitarity. Additionally, BELLE found hints for an excess in $B_d\to\tau^+\tau^-$. Concerning NP explanations, the vector leptoquark $SU(2)$ singlet is of special interest since it is the only single particle extension of the SM which can (in principle) address all the anomalies described above. For this purpose, large couplings to $\tau$ leptons are necessary and loop effects, which we calculate in this article, become important. Including them in our phenomenological analysis, we find that neither the tension in $V_{us}$ nor the excess in $B_d\to\tau^+\tau^-$ can be fully explained without violating bounds from $K\to\pi\nu\bar\nu$. However, one can account for $b\to c\tau\nu$ and $b\to u\tau\nu$ data finding intriguing correlations with $B_{q}\to\tau^+\tau^-$ and $K\to \pi\nu\bar\nu$. Furthermore, the explanation of $b\to c\tau\nu$ predicts a positive shift in $C_7$ and a negative one in $C_9$, being nicely in agreement with the global fit to $b\to s\ell^+\ell^-$ data. Finally, we point out that one can fully account for \bctaunu and $b\to s\ell^+\ell^-$ without violating bounds from $\tau\to \phi\mu$, $\Upsilon\to\tau\mu$ or $b\to s\tau\mu$ processes.
|
hep-ph/9204230
|
Rahul Basu
|
Rahul Basu, Debajyoti Choudhury
|
Confinement in a Chromoelectric Vacuum
|
11 pages, Latex file
| null | null | null |
hep-ph
| null |
A chromoelectric vacuum that confines both gluon and quark degrees of freedom
(in the sense that they do not exist as asymptotic states) is constructed.
However some degrees of freedom still exist as asymptotic states thereby
allowing colour singlets to propagate.
|
[
{
"created": "Wed, 22 Apr 1992 14:30:39 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Basu",
"Rahul",
""
],
[
"Choudhury",
"Debajyoti",
""
]
] |
A chromoelectric vacuum that confines both gluon and quark degrees of freedom (in the sense that they do not exist as asymptotic states) is constructed. However some degrees of freedom still exist as asymptotic states thereby allowing colour singlets to propagate.
|
1212.0929
|
Joshua Sayre
|
Chung Kao and Joshua Sayre
|
Confirming the LHC Higgs Discovery with WW
| null | null |
10.1016/j.physletb.2013.04.028
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We investigate the prospects of observing a neutral Higgs boson decaying into
a pair of $W$ bosons (one real and the other virtual), followed by the $W$
decays into $qq' \ell\nu$ or $jj\ell\nu$ at the CERN Large Hadron Collider
(LHC). Assuming that the missing transverse energy comes solely from the
neutrino in $W$ decay, we can reconstruct the $W$ masses and then the Higgs
mass. At the LHC with a center of mass energy ($\sqrt{s}$) of 8 TeV and an
integrated luminosity ($L$) of 25 fb$^{-1}$, we can potentially establish a
$6\sigma$ signal. A $5\sigma$ discovery of $H \to WW^* \to jj\ell\nu$ for
$\sqrt{s} = 14$ TeV can be achieved with $L = $ 6 fb$^{-1}$. The discovery of
$H \to WW$ implies that the recently discovered new boson is a CP-even scalar
if its spin is zero. In addition, this channel will provide a good opportunity
to study the $HWW$ coupling.
|
[
{
"created": "Wed, 5 Dec 2012 04:04:45 GMT",
"version": "v1"
}
] |
2015-06-12
|
[
[
"Kao",
"Chung",
""
],
[
"Sayre",
"Joshua",
""
]
] |
We investigate the prospects of observing a neutral Higgs boson decaying into a pair of $W$ bosons (one real and the other virtual), followed by the $W$ decays into $qq' \ell\nu$ or $jj\ell\nu$ at the CERN Large Hadron Collider (LHC). Assuming that the missing transverse energy comes solely from the neutrino in $W$ decay, we can reconstruct the $W$ masses and then the Higgs mass. At the LHC with a center of mass energy ($\sqrt{s}$) of 8 TeV and an integrated luminosity ($L$) of 25 fb$^{-1}$, we can potentially establish a $6\sigma$ signal. A $5\sigma$ discovery of $H \to WW^* \to jj\ell\nu$ for $\sqrt{s} = 14$ TeV can be achieved with $L = $ 6 fb$^{-1}$. The discovery of $H \to WW$ implies that the recently discovered new boson is a CP-even scalar if its spin is zero. In addition, this channel will provide a good opportunity to study the $HWW$ coupling.
|
hep-ph/0412418
|
Chaehyun Yu
|
C.S. Kim, Sechul Oh, Chaehyun Yu
|
Strong phase shifts and color-suppressed tree amplitudes in B -> D K^(*)
and B -> D pi, D rho decays
|
17 pages, 4 figures, revised version, to appear in Phys. Lett. B
|
Phys.Lett. B621 (2005) 259-268
|
10.1016/j.physletb.2005.06.068
| null |
hep-ph
| null |
We analyze the decay processes B \to DK, DK^*, D\pi, and D\rho in a
model-independent way. Using the quark diagram approach, we determine the
magnitudes of the relevant amplitudes and the relative strong phase shifts. In
order to find the most likely values of the magnitudes and the relative strong
phases of the amplitudes in a statistically reliable way, we use the \chi^2
minimization technique. We find that the strong phase difference between the
color-allowed and the color-suppressed tree amplitude can be large and is
non-zero at 1 \sigma level with the present data. The color-suppressed tree
contributions are found to be sizably enhanced. We also examine the validity of
factorization and estimate the breaking effects of flavor SU(3) symmetry in B
\to DK, D\pi and in B \to DK^*, D\rho.
|
[
{
"created": "Thu, 30 Dec 2004 12:11:59 GMT",
"version": "v1"
},
{
"created": "Wed, 27 Jul 2005 07:17:59 GMT",
"version": "v2"
}
] |
2009-11-10
|
[
[
"Kim",
"C. S.",
""
],
[
"Oh",
"Sechul",
""
],
[
"Yu",
"Chaehyun",
""
]
] |
We analyze the decay processes B \to DK, DK^*, D\pi, and D\rho in a model-independent way. Using the quark diagram approach, we determine the magnitudes of the relevant amplitudes and the relative strong phase shifts. In order to find the most likely values of the magnitudes and the relative strong phases of the amplitudes in a statistically reliable way, we use the \chi^2 minimization technique. We find that the strong phase difference between the color-allowed and the color-suppressed tree amplitude can be large and is non-zero at 1 \sigma level with the present data. The color-suppressed tree contributions are found to be sizably enhanced. We also examine the validity of factorization and estimate the breaking effects of flavor SU(3) symmetry in B \to DK, D\pi and in B \to DK^*, D\rho.
|
1207.5911
|
Shinya Matsuzaki
|
Shinya Matsuzaki and Koichi Yamawaki
|
Is 125 GeV techni-dilaton found at LHC?
|
2 eps figures, 5 pages, latex; typos fixed, version published in PLB
| null |
10.1016/j.physletb.2013.01.031
|
MISC-2012-14
|
hep-ph hep-ex
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
A new particle at around 125 GeV has been observed at the LHC, which we show
could be identified with the techni-dilaton (TD) predicted in the walking
technicolor and thus should be an evidence of walking technicolor. The TD is a
pseudo Nambu-Goldstone boson for the approximate scale symmetry spontaneously
broken by techni-fermion condensation, with its lightness being ensured by the
approximate scale invariance of the walking technicolor. We test the
goodness-of-fit of the TD signatures using the presently available LHC data
set, and show that the 125 GeV TD is actually favored by the current data to
explain the reported signal strengths in the global fit as well as in each
channel including the coupling properties, most notably the somewhat large
diphoton event rate.
|
[
{
"created": "Wed, 25 Jul 2012 07:57:13 GMT",
"version": "v1"
},
{
"created": "Fri, 25 Jan 2013 01:03:05 GMT",
"version": "v2"
}
] |
2015-06-05
|
[
[
"Matsuzaki",
"Shinya",
""
],
[
"Yamawaki",
"Koichi",
""
]
] |
A new particle at around 125 GeV has been observed at the LHC, which we show could be identified with the techni-dilaton (TD) predicted in the walking technicolor and thus should be an evidence of walking technicolor. The TD is a pseudo Nambu-Goldstone boson for the approximate scale symmetry spontaneously broken by techni-fermion condensation, with its lightness being ensured by the approximate scale invariance of the walking technicolor. We test the goodness-of-fit of the TD signatures using the presently available LHC data set, and show that the 125 GeV TD is actually favored by the current data to explain the reported signal strengths in the global fit as well as in each channel including the coupling properties, most notably the somewhat large diphoton event rate.
|
hep-ph/0605101
|
Enrique Fernandez-Martinez
|
E. Fernandez-Martinez
|
Solving Degeneracies at a $\beta$-Beam by Combining Ions
|
Talk given at the XLIrst Rencontres de Moriond session devoted to
Electroweak Interactions And Unified Theories in March 2006. 4 pages, 4
figures
| null | null | null |
hep-ph
| null |
We study how the eightfold-degeneracy in the ($\theta_{13},\delta$) plane
observed in $\gamma \sim 100$ $\beta$-beams can be reduced by periodically
changing the ions in the storage ring. This ``ions cocktail'' allows to change
the neutrino energy, at fixed $\gamma$, by choosing ions with different decay
energies. We propose to combine the standard $^6$He and $^{18}$Ne beams with
$^8$Li and $^8$B ones. These latter two ions have peaked $\nu_e \to \nu_\mu$
oscillation probabilities for $\gamma = 100$ at a baseline $L \sim 700$ Km. At
this distance and this $\gamma$ the oscillation probability of $^6$He and
$^{18}$Ne neutrinos is at its second maximum. This setup is particularly suited
for large enough values of $\theta_{13}$ (within reach at T2K-I) and it allows
solving most of the eightfold-degeneracy, measuring $\theta_{13}, \delta$ and
the sign of the atmospheric mass difference for values of $\theta_{13} \geq
5^\circ$.
|
[
{
"created": "Tue, 9 May 2006 15:16:50 GMT",
"version": "v1"
},
{
"created": "Thu, 17 Apr 2008 07:56:36 GMT",
"version": "v2"
}
] |
2008-04-17
|
[
[
"Fernandez-Martinez",
"E.",
""
]
] |
We study how the eightfold-degeneracy in the ($\theta_{13},\delta$) plane observed in $\gamma \sim 100$ $\beta$-beams can be reduced by periodically changing the ions in the storage ring. This ``ions cocktail'' allows to change the neutrino energy, at fixed $\gamma$, by choosing ions with different decay energies. We propose to combine the standard $^6$He and $^{18}$Ne beams with $^8$Li and $^8$B ones. These latter two ions have peaked $\nu_e \to \nu_\mu$ oscillation probabilities for $\gamma = 100$ at a baseline $L \sim 700$ Km. At this distance and this $\gamma$ the oscillation probability of $^6$He and $^{18}$Ne neutrinos is at its second maximum. This setup is particularly suited for large enough values of $\theta_{13}$ (within reach at T2K-I) and it allows solving most of the eightfold-degeneracy, measuring $\theta_{13}, \delta$ and the sign of the atmospheric mass difference for values of $\theta_{13} \geq 5^\circ$.
|
1805.04423
|
Lorenzo Calibbi
|
Lorenzo Calibbi, Laura Lopez-Honorez, Steven Lowette, Alberto Mariotti
|
Singlet-Doublet Dark Matter Freeze-in: LHC displaced signatures versus
cosmology
|
42 pages, 14 figures; v2: minor discussions, clarifications, and
references added
|
JHEP 1809 (2018) 037
|
10.1007/JHEP09(2018)037
|
ULB-TH/18-07
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We study the Singlet-Doublet dark matter model in the regime of feeble
couplings, where the dark matter abundance is obtained via the freeze-in
mechanism. As a consequence of the small couplings, the heavier particles in
the model are long-lived with decay length at typical scales of collider
experiments. We analyse the collider signatures of the model, characterised by
displaced $h$ and $Z$ bosons plus missing momentum, employing current LHC
searches for displaced vertices and missing energy to significantly constrain
the parameter space of the model. We also take into account the cosmological
bounds relevant for our light dark matter candidate arising from Lyman-$\alpha$
forest constraints. Our analysis emphasises the interplay between displaced
signatures at the LHC and cosmology for dark matter candidates whose relic
abundance is obtained through the freeze-in mechanism.
|
[
{
"created": "Fri, 11 May 2018 14:33:47 GMT",
"version": "v1"
},
{
"created": "Wed, 12 Sep 2018 08:39:53 GMT",
"version": "v2"
}
] |
2018-09-13
|
[
[
"Calibbi",
"Lorenzo",
""
],
[
"Lopez-Honorez",
"Laura",
""
],
[
"Lowette",
"Steven",
""
],
[
"Mariotti",
"Alberto",
""
]
] |
We study the Singlet-Doublet dark matter model in the regime of feeble couplings, where the dark matter abundance is obtained via the freeze-in mechanism. As a consequence of the small couplings, the heavier particles in the model are long-lived with decay length at typical scales of collider experiments. We analyse the collider signatures of the model, characterised by displaced $h$ and $Z$ bosons plus missing momentum, employing current LHC searches for displaced vertices and missing energy to significantly constrain the parameter space of the model. We also take into account the cosmological bounds relevant for our light dark matter candidate arising from Lyman-$\alpha$ forest constraints. Our analysis emphasises the interplay between displaced signatures at the LHC and cosmology for dark matter candidates whose relic abundance is obtained through the freeze-in mechanism.
|
2310.18797
|
Xing Fan
|
Xing Fan and Mario Reig
|
New bounds and future prospects for axion force searches at Penning trap
experiments
|
4 pages, 1 figure
| null | null | null |
hep-ph hep-ex physics.atom-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
In this note we consider Penning trap experiments as probes of axion-mediated
forces. We show that the current measurement of electron's $g$-factor already
sets a new exclusion limit for monopole-dipole axion forces acting on the
electron spin. We also show that the Penning trap's capability of switching an
electron and a positron can isolate the effect of an axion force and suppress
systematic effects.
|
[
{
"created": "Sat, 28 Oct 2023 19:54:36 GMT",
"version": "v1"
},
{
"created": "Fri, 15 Dec 2023 02:31:14 GMT",
"version": "v2"
}
] |
2023-12-18
|
[
[
"Fan",
"Xing",
""
],
[
"Reig",
"Mario",
""
]
] |
In this note we consider Penning trap experiments as probes of axion-mediated forces. We show that the current measurement of electron's $g$-factor already sets a new exclusion limit for monopole-dipole axion forces acting on the electron spin. We also show that the Penning trap's capability of switching an electron and a positron can isolate the effect of an axion force and suppress systematic effects.
|
hep-ph/0205273
|
Gabriel Lopez Castro
|
G. Lopez Castro, H. B. Mayorga and J. H. Munoz
|
Non-leptonic decays of the B_c into tensor mesons
|
14 pages, accepted for publication in JPG
|
J.Phys.G28:2241-2248,2002
|
10.1088/0954-3899/28/8/309
| null |
hep-ph
| null |
We have computed the branching ratios of the exclusive pseudoscalar (vector)
+ tensor modes that are allowed in the decays of the B_c meson. The dominant
spectator and annihilation contributions in those decays are evaluated using
the factorization hypothesis. We find that some of these decay channels, such
as B_c --> (\rho^-, D_s^{*-}, D_s^{-})\chi_{c2} and B_c^ -->\pi^-
\bar{B_{s2}^{*0}}, have branching ratios of the order of 10^{-4}, which seems
to be at the reach of forthcoming experiments at the LHC. The inclusive
branching fraction of the two-body B_c decays involving tensor particles is
approximately 1.28 x10^{-3}. At the dynamical level, it is interesting to
observe that the exclusive decays B_c --> K^-(\pi^-)\bar{D_2^{*0}}, \pi^0
D_2^{*-}, \eta^{'} D_{s2}^{*-} are dominated by the annihilation contributions.
|
[
{
"created": "Fri, 24 May 2002 01:42:45 GMT",
"version": "v1"
}
] |
2008-11-26
|
[
[
"Castro",
"G. Lopez",
""
],
[
"Mayorga",
"H. B.",
""
],
[
"Munoz",
"J. H.",
""
]
] |
We have computed the branching ratios of the exclusive pseudoscalar (vector) + tensor modes that are allowed in the decays of the B_c meson. The dominant spectator and annihilation contributions in those decays are evaluated using the factorization hypothesis. We find that some of these decay channels, such as B_c --> (\rho^-, D_s^{*-}, D_s^{-})\chi_{c2} and B_c^ -->\pi^- \bar{B_{s2}^{*0}}, have branching ratios of the order of 10^{-4}, which seems to be at the reach of forthcoming experiments at the LHC. The inclusive branching fraction of the two-body B_c decays involving tensor particles is approximately 1.28 x10^{-3}. At the dynamical level, it is interesting to observe that the exclusive decays B_c --> K^-(\pi^-)\bar{D_2^{*0}}, \pi^0 D_2^{*-}, \eta^{'} D_{s2}^{*-} are dominated by the annihilation contributions.
|
1407.0232
|
Heidi Rzehak
|
Thomas Hahn, Sven Heinemeyer, Wolfgang Hollik, Heidi Rzehak, Georg
Weiglein
|
Higher-Order Contributions in Higgs Sectors of Supersymmetric Models
|
8 pages, latex, pdf figures, contribution to the proceedings of the
conference "Loops and Legs in Quantum Field Theory - LL 2014, 27 April - 2
May 2014, Weimar, Germany
| null | null |
FR-PHENO-2014-007, MPP-2014-262
|
hep-ph
|
http://creativecommons.org/licenses/by-nc-sa/3.0/
|
In 2012, the discovery of a particle compatible with a Higgs boson of a mass
of roughly 125 GeV was announced. This great success is now being followed by
the identification of the nature of this particle and the particle's properties
are being measured. One of these properties is the Higgs boson mass which is
already known very precisely with an experimental uncertainty of below 1 GeV.
In some extensions of the Standard Model, like in supersymmetric extensions,
the Higgs boson mass can be predicted and hence, the measured mass constrains
the parameters of the model. For a full exploitation of this constraint, a
precise theoretical prediction is needed. The presented combination of the
results obtained by the Feynman diagrammatic approach and the renormalization
group equation approach improves the known Higgs mass prediction for larger
mass scales of the superpartner particles.
|
[
{
"created": "Tue, 1 Jul 2014 13:30:02 GMT",
"version": "v1"
}
] |
2014-07-02
|
[
[
"Hahn",
"Thomas",
""
],
[
"Heinemeyer",
"Sven",
""
],
[
"Hollik",
"Wolfgang",
""
],
[
"Rzehak",
"Heidi",
""
],
[
"Weiglein",
"Georg",
""
]
] |
In 2012, the discovery of a particle compatible with a Higgs boson of a mass of roughly 125 GeV was announced. This great success is now being followed by the identification of the nature of this particle and the particle's properties are being measured. One of these properties is the Higgs boson mass which is already known very precisely with an experimental uncertainty of below 1 GeV. In some extensions of the Standard Model, like in supersymmetric extensions, the Higgs boson mass can be predicted and hence, the measured mass constrains the parameters of the model. For a full exploitation of this constraint, a precise theoretical prediction is needed. The presented combination of the results obtained by the Feynman diagrammatic approach and the renormalization group equation approach improves the known Higgs mass prediction for larger mass scales of the superpartner particles.
|
1604.07085
|
Kenneth Lane
|
Kenneth Lane and Lukas Pritchett
|
The Light Composite Higgs in Strong Extended Technicolor
|
23 pages, 3 figures. Updated discussion of diboson resonance status
in view of current Run 2 data. Version to be published in JHEP
| null |
10.1007/JHEP06(2017)140
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
This paper extends an earlier one describing the Higgs boson $H$ as a light
composite scalar in a strong extended technicolor model of electroweak symmetry
breaking. The Higgs mass $M_H$ is made much smaller than $\Lambda_{ETC}$ by
tuning the ETC coupling very close to the critical value for electroweak
symmetry breaking. The technicolor interaction, neglected in the earlier paper,
is considered here. Its weakness relative to extended technicolor is essential
to understanding the lightness of $H$ compared to the low-lying spin-one
technihadrons. Technicolor cannot be completely ignored, but implementing
technigluon exchange together with strong extended technicolor appears
difficult. We propose a solution that turns out to leave the results of the
earlier paper essentially unchanged. An argument is then presented that masses
of the spin-one technifermion bound states, $\rho_H$ and $a_H$, are much larger
than $M_H$ and, plausibly, controlled by technicolor. Assuming $M_{\rho_H}$ and
$M_{a_H}$ are in the TeV-energy region, we identify $\rho_H$ and $a_H$ with the
diboson excesses observed near $2\,{\rm TeV}$ by ATLAS and CMS in LHC Run 1
data, and we discuss their phenomenology for Runs 2 and 3.
|
[
{
"created": "Sun, 24 Apr 2016 21:33:07 GMT",
"version": "v1"
},
{
"created": "Sat, 1 Jul 2017 14:52:46 GMT",
"version": "v2"
}
] |
2017-07-04
|
[
[
"Lane",
"Kenneth",
""
],
[
"Pritchett",
"Lukas",
""
]
] |
This paper extends an earlier one describing the Higgs boson $H$ as a light composite scalar in a strong extended technicolor model of electroweak symmetry breaking. The Higgs mass $M_H$ is made much smaller than $\Lambda_{ETC}$ by tuning the ETC coupling very close to the critical value for electroweak symmetry breaking. The technicolor interaction, neglected in the earlier paper, is considered here. Its weakness relative to extended technicolor is essential to understanding the lightness of $H$ compared to the low-lying spin-one technihadrons. Technicolor cannot be completely ignored, but implementing technigluon exchange together with strong extended technicolor appears difficult. We propose a solution that turns out to leave the results of the earlier paper essentially unchanged. An argument is then presented that masses of the spin-one technifermion bound states, $\rho_H$ and $a_H$, are much larger than $M_H$ and, plausibly, controlled by technicolor. Assuming $M_{\rho_H}$ and $M_{a_H}$ are in the TeV-energy region, we identify $\rho_H$ and $a_H$ with the diboson excesses observed near $2\,{\rm TeV}$ by ATLAS and CMS in LHC Run 1 data, and we discuss their phenomenology for Runs 2 and 3.
|
1108.5847
|
Vadim Babkin
|
M.Yu. Barabanov, A.S. Vodopyanov, V.Kh. Dodokhov and V.A. Babkin
|
Application of High Quality Antiproton Beam with Momentum Ranging from 1
GeV/c to 15 GeV/c to Study Charmonium and Charmed Hybrids
| null | null | null | null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The elaborate analysis of spectrum of charmonium states and charmed hybrids
in the mass region over DD-threshold is given. The combined approach based on
the potential model and relativistic spherical symmetric top model for decay
products has been proposed. The experimental data from different collaborations
were analyzed. Especial attention was given to the new states with the hidden
charm discovered recently. Eight of these states may be interpreted as higher
laying radial excited charmoniumstates. Butmuchmore data on different decay
modes are needed for deeper analysis. These data can be derived directly from
the experiments using high quality antiproton beam with the momentum ranging
from 1 GeV/c to 15 GeV/c (PANDA experiment at FAIR).
|
[
{
"created": "Tue, 30 Aug 2011 07:00:43 GMT",
"version": "v1"
}
] |
2011-08-31
|
[
[
"Barabanov",
"M. Yu.",
""
],
[
"Vodopyanov",
"A. S.",
""
],
[
"Dodokhov",
"V. Kh.",
""
],
[
"Babkin",
"V. A.",
""
]
] |
The elaborate analysis of spectrum of charmonium states and charmed hybrids in the mass region over DD-threshold is given. The combined approach based on the potential model and relativistic spherical symmetric top model for decay products has been proposed. The experimental data from different collaborations were analyzed. Especial attention was given to the new states with the hidden charm discovered recently. Eight of these states may be interpreted as higher laying radial excited charmoniumstates. Butmuchmore data on different decay modes are needed for deeper analysis. These data can be derived directly from the experiments using high quality antiproton beam with the momentum ranging from 1 GeV/c to 15 GeV/c (PANDA experiment at FAIR).
|
hep-ph/9908223
|
Hitoshi Murayama
|
Takeo Moroi (IAS) and Hitoshi Murayama (UC Berkeley,LBNL)
|
The Minimal Supersymmetric Leptogenesis
|
14 pages, references added, typos corrected
|
JHEP 0007:009,2000
|
10.1088/1126-6708/2000/07/009
|
IASSNS-HEP-99/69, LBNL-44042, UCB-PTH-99/29
|
hep-ph astro-ph
| null |
We reanalyze the supersymmetric leptogenesis model by one of the authors (HM)
and Yanagida based on \tilde{L} = H_u flat direction in detail. We point out
that the appropriate amount of baryon asymmetry can be generated in this model
with the neutrino mass matrix consistent with the atmospheric neutrino
oscillation and solutions to the solar neutrino problem, preferably the small
angle MSW solution. The reheating temperature can be low enough to avoid the
cosmological gravitino problem. This model is the minimal one because it does
not rely on any new physics beyond supersymmetry and Majorana neutrino masses.
|
[
{
"created": "Mon, 2 Aug 1999 21:47:37 GMT",
"version": "v1"
},
{
"created": "Mon, 16 Aug 1999 21:53:25 GMT",
"version": "v2"
}
] |
2009-10-31
|
[
[
"Moroi",
"Takeo",
"",
"IAS"
],
[
"Murayama",
"Hitoshi",
"",
"UC Berkeley,LBNL"
]
] |
We reanalyze the supersymmetric leptogenesis model by one of the authors (HM) and Yanagida based on \tilde{L} = H_u flat direction in detail. We point out that the appropriate amount of baryon asymmetry can be generated in this model with the neutrino mass matrix consistent with the atmospheric neutrino oscillation and solutions to the solar neutrino problem, preferably the small angle MSW solution. The reheating temperature can be low enough to avoid the cosmological gravitino problem. This model is the minimal one because it does not rely on any new physics beyond supersymmetry and Majorana neutrino masses.
|
hep-ph/9904412
|
David Dooling
|
David Dooling, Kyungsik Kang and Sin Kyu Kang
|
Higgs Boson Bounds in Three and Four Generation Scenarios
|
7 pages, 4 figures. To be published in Physical Review D
|
Phys.Rev. D60 (1999) 017701
|
10.1103/PhysRevD.60.017701
|
BROWN-HET-1182, KIAS-P99026
|
hep-ph
| null |
In light of recent experimental results, we present updated bounds on the
lightest Higgs boson mass in the Standard Model (SM) and in the Minimal
Supersymmetric extension of the Standard Model (MSSM). The vacuum stability
lower bound on the pure SM Higgs boson mass when the SM is taken to be valid up
to the Planck scale lies above the MSSM lightest Higgs boson mass upper bound
for a large amount of SUSY parameter space. If the lightest Higgs boson is
detected with a mass M_{H} < 134 GeV (150 GeV) for a top quark mass M_{top} =
172 GeV (179 GeV), it may indicate the existence of a fourth generation of
fermions. The region of inconsistency is removed and the MSSM is salvagable for
such values of M_{H} if one postulates the existence of a fourth generation of
leptons and quarks with isodoublet degenerate masses M_{L} and M_{Q} such that
60 GeV < M_{L} < 110 GeV and M_{Q} > 170 GeV.
|
[
{
"created": "Tue, 20 Apr 1999 18:57:43 GMT",
"version": "v1"
}
] |
2009-10-31
|
[
[
"Dooling",
"David",
""
],
[
"Kang",
"Kyungsik",
""
],
[
"Kang",
"Sin Kyu",
""
]
] |
In light of recent experimental results, we present updated bounds on the lightest Higgs boson mass in the Standard Model (SM) and in the Minimal Supersymmetric extension of the Standard Model (MSSM). The vacuum stability lower bound on the pure SM Higgs boson mass when the SM is taken to be valid up to the Planck scale lies above the MSSM lightest Higgs boson mass upper bound for a large amount of SUSY parameter space. If the lightest Higgs boson is detected with a mass M_{H} < 134 GeV (150 GeV) for a top quark mass M_{top} = 172 GeV (179 GeV), it may indicate the existence of a fourth generation of fermions. The region of inconsistency is removed and the MSSM is salvagable for such values of M_{H} if one postulates the existence of a fourth generation of leptons and quarks with isodoublet degenerate masses M_{L} and M_{Q} such that 60 GeV < M_{L} < 110 GeV and M_{Q} > 170 GeV.
|
1512.02265
|
Sungwoo Hong
|
Kaustubh Agashe, Roberto Franceschini, Sungwoo Hong, and Doojin Kim
|
Energy spectra of massive two-body decay products and mass measurement
|
37 pages, 8 figures
| null |
10.1007/JHEP04(2016)151
|
UMD-PP-015-015, CERN-PH-TH-2015-288
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We have recently established a new method for measuring the mass of unstable
particles produced at hadron colliders based on the analysis of the energy
distribution of a massless product from their two-body decays. The central
ingredient of our proposal is the remarkable result that, for an unpolarized
decaying particle, the location of the peak in the energy distribution of the
observed decay product is identical to the (fixed) value of the energy that
this particle would have in the rest-frame of the decaying particle, which, in
turn, is a simple function of the involved masses. In addition, we utilized the
property that this energy distribution is symmetric around the location of peak
when energy is plotted on a logarithmic scale. The general strategy was
demonstrated in several specific cases, including both beyond the SM particles,
as well as for the top quark. In the present work, we generalize this method to
the case of a massive decay product from a two-body decay; this procedure is
far from trivial because (in general) both the above- mentioned properties are
no longer valid. Nonetheless, we propose a suitably modified parametrization of
the energy distribution that was used successfully for the massless case, which
can deal with the massive case as well. We establish the accuracy of this
parametrization using concrete examples of energy spectra of Z bosons from the
decay of a heavier stop into a Z boson and a lighter stop. We then study a
realistic application for the same process, but now including dominant
backgrounds and using foreseeable statistics at LHC14, in order to determine
the performance of this method for an actual mass measurement. The upshot of
our present and previous work is that, in spite of energy being a
Lorentz-variant quantity, its distribution emerges as a powerful tool for mass
measurement at hadron colliders.
|
[
{
"created": "Mon, 7 Dec 2015 22:20:12 GMT",
"version": "v1"
}
] |
2016-05-25
|
[
[
"Agashe",
"Kaustubh",
""
],
[
"Franceschini",
"Roberto",
""
],
[
"Hong",
"Sungwoo",
""
],
[
"Kim",
"Doojin",
""
]
] |
We have recently established a new method for measuring the mass of unstable particles produced at hadron colliders based on the analysis of the energy distribution of a massless product from their two-body decays. The central ingredient of our proposal is the remarkable result that, for an unpolarized decaying particle, the location of the peak in the energy distribution of the observed decay product is identical to the (fixed) value of the energy that this particle would have in the rest-frame of the decaying particle, which, in turn, is a simple function of the involved masses. In addition, we utilized the property that this energy distribution is symmetric around the location of peak when energy is plotted on a logarithmic scale. The general strategy was demonstrated in several specific cases, including both beyond the SM particles, as well as for the top quark. In the present work, we generalize this method to the case of a massive decay product from a two-body decay; this procedure is far from trivial because (in general) both the above- mentioned properties are no longer valid. Nonetheless, we propose a suitably modified parametrization of the energy distribution that was used successfully for the massless case, which can deal with the massive case as well. We establish the accuracy of this parametrization using concrete examples of energy spectra of Z bosons from the decay of a heavier stop into a Z boson and a lighter stop. We then study a realistic application for the same process, but now including dominant backgrounds and using foreseeable statistics at LHC14, in order to determine the performance of this method for an actual mass measurement. The upshot of our present and previous work is that, in spite of energy being a Lorentz-variant quantity, its distribution emerges as a powerful tool for mass measurement at hadron colliders.
|
1410.5488
|
Chien-Yi Chen
|
Chien-Yi Chen, S. Dawson, and I. M. Lewis
|
Exploring Resonant di-Higgs production in the Higgs Singlet Model
|
25 pages, 14 figures. Version approved for publication. Discussion of
Z2 symmetric limit improved and references added
|
Phys. Rev. D 91, 035015 (2015)
|
10.1103/PhysRevD.91.035015
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We study the enhancement of the di-Higgs production cross section resulting
from the resonant decay of a heavy Higgs boson at hadron colliders in a model
with a Higgs singlet. This enhancement of the double Higgs production rate is
crucial in understanding the structure of the scalar potential and we determine
the maximum allowed enhancement such that the electroweak minimum is a global
minimum. The di-Higgs production enhancement can be as large as a factor of ~
18 (13) for the mass of the heavy Higgs around 270 (420) GeV relative to the
Standard Model rate at 14 TeV for parameters corresponding to a global
electroweak minimum.
|
[
{
"created": "Mon, 20 Oct 2014 22:25:13 GMT",
"version": "v1"
},
{
"created": "Fri, 12 Dec 2014 16:26:36 GMT",
"version": "v2"
}
] |
2015-03-05
|
[
[
"Chen",
"Chien-Yi",
""
],
[
"Dawson",
"S.",
""
],
[
"Lewis",
"I. M.",
""
]
] |
We study the enhancement of the di-Higgs production cross section resulting from the resonant decay of a heavy Higgs boson at hadron colliders in a model with a Higgs singlet. This enhancement of the double Higgs production rate is crucial in understanding the structure of the scalar potential and we determine the maximum allowed enhancement such that the electroweak minimum is a global minimum. The di-Higgs production enhancement can be as large as a factor of ~ 18 (13) for the mass of the heavy Higgs around 270 (420) GeV relative to the Standard Model rate at 14 TeV for parameters corresponding to a global electroweak minimum.
|
hep-ph/9702237
|
Jorge L. Lopez
|
T. Li, J. Lopez, and D. Nanopoulos
|
M-theory Inspired No-scale Supergravity
|
8 pages, LaTeX, 3 figures (included)
|
Mod.Phys.Lett. A12 (1997) 2647-2654
|
10.1142/S0217732397002788
|
CTP-TAMU-07/97, DOE/ER/40717-39
|
hep-ph hep-th
| null |
We propose a supergravity model that contains elements recently shown to
arise in the strongly-coupled limit of the $E_8\times E_8$ heterotic string
(M-theory), including a no-scale--like K\"ahler potential, the identification
of the string scale with the gauge coupling unification scale, and the onset of
supersymmetry breaking at an intermediate scale determined by the size of the
eleventh dimension of M-theory. We also study the phenomenological consequences
of such scenario, which include a rather constrained sparticle spectrum within
the reach of present-generation particle accelerators.
|
[
{
"created": "Mon, 3 Feb 1997 21:22:40 GMT",
"version": "v1"
}
] |
2009-10-30
|
[
[
"Li",
"T.",
""
],
[
"Lopez",
"J.",
""
],
[
"Nanopoulos",
"D.",
""
]
] |
We propose a supergravity model that contains elements recently shown to arise in the strongly-coupled limit of the $E_8\times E_8$ heterotic string (M-theory), including a no-scale--like K\"ahler potential, the identification of the string scale with the gauge coupling unification scale, and the onset of supersymmetry breaking at an intermediate scale determined by the size of the eleventh dimension of M-theory. We also study the phenomenological consequences of such scenario, which include a rather constrained sparticle spectrum within the reach of present-generation particle accelerators.
|
hep-ph/9702202
| null |
Junji Hisano (Univ of Minnesota), Shingo Kiyoura (Tokyo Inst of Tech,
KEK), Hitoshi Murayama (UC Berkeley, LBNL)
|
Upper Bound on R_b in Two Higgs Doublet Model from Lepton Universality
|
14 pages, LaTeX with epsfig.sty, including 5 figures
|
Phys.Lett.B399:156-162,1997
|
10.1016/S0370-2693(97)00259-1
|
MN-HEP-1527, TPI-01/97, KEK-TH-509, TIT/HEP-359, LBNL-39902,
UCB-pth-97/05
|
hep-ph
| null |
It has been known that $R_b$ can be enhanced in the two Higgs doublet model
if $\tan \beta$ is large. We point out that a similar enhancement in $\Gamma(Z
\to \tau^+ \tau^-)$ is large enough to place a constraint on such a
possibility. We obtain a 95% CL upper bound $\Delta R_b/R_{b} < 0.73%$ in this
model for the $\overline{MS}$ mass $m_{b} (m_{Z}) = 3.0$ GeV. The 1996 world
average is $\Delta R_{b}/R_{b}$ = $0.97% \pm 0.51%$. We used the $m_{b}(m_{Z})$
to determine the bottom Yukawa coupling instead of $m_b(m_{b})$ unlike in
previous analyses, and also an improved experimental test of the lepton
universality in $Z$ decay, which made our results qualitatively different.
|
[
{
"created": "Sun, 2 Feb 1997 19:31:16 GMT",
"version": "v1"
}
] |
2016-09-06
|
[
[
"Hisano",
"Junji",
"",
"Univ of Minnesota"
],
[
"Kiyoura",
"Shingo",
"",
"Tokyo Inst of Tech,\n KEK"
],
[
"Murayama",
"Hitoshi",
"",
"UC Berkeley, LBNL"
]
] |
It has been known that $R_b$ can be enhanced in the two Higgs doublet model if $\tan \beta$ is large. We point out that a similar enhancement in $\Gamma(Z \to \tau^+ \tau^-)$ is large enough to place a constraint on such a possibility. We obtain a 95% CL upper bound $\Delta R_b/R_{b} < 0.73%$ in this model for the $\overline{MS}$ mass $m_{b} (m_{Z}) = 3.0$ GeV. The 1996 world average is $\Delta R_{b}/R_{b}$ = $0.97% \pm 0.51%$. We used the $m_{b}(m_{Z})$ to determine the bottom Yukawa coupling instead of $m_b(m_{b})$ unlike in previous analyses, and also an improved experimental test of the lepton universality in $Z$ decay, which made our results qualitatively different.
|
1502.07784
|
Nejc Ko\v{s}nik
|
Ilja Dorsner, Svjetlana Fajfer, Admir Greljo, Jernej F. Kamenik, Nejc
Kosnik and Ivan Nisandzic
|
New Physics Models Facing Lepton Flavor Violating Higgs Decays at the
Percent Level
|
34 pages, 9 figures, expanded Section V.D with the fine-tuning
solution; conclusions unchanged
| null |
10.1007/JHEP06(2015)108
|
ZU-TH-2/15, DO-TH 15/04
|
hep-ph hep-ex
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We speculate about the possible interpretations of the recently observed
excess in the $h \to \tau \mu$ decay. We derive a robust lower bound on the
Higgs boson coupling strength to a tau and a muon, even in presence of the most
general new physics affecting other Higgs properties. Then we reevaluate
complementary indirect constraints coming from low energy observables as well
as from theoretical considerations. In particular, the tentative signal should
lead to $\tau \to \mu \gamma$ at rates which could be observed at Belle II. In
turn we show that, barring fine-tuned cancellations, the effect can only be
accommodated within models with an extended scalar sector. These general
conclusions are demonstrated using a number of explicit new physics models.
Finally we show how, given the $h \to \tau \mu$ signal, the current and future
searches for $\mu \to e \gamma$ and $\mu \to e$ nuclear conversions
unambiguously constrain the allowed rates for $h \to \tau e$.
|
[
{
"created": "Thu, 26 Feb 2015 23:09:45 GMT",
"version": "v1"
},
{
"created": "Fri, 6 Mar 2015 21:15:05 GMT",
"version": "v2"
},
{
"created": "Fri, 9 Oct 2015 10:12:16 GMT",
"version": "v3"
}
] |
2015-10-12
|
[
[
"Dorsner",
"Ilja",
""
],
[
"Fajfer",
"Svjetlana",
""
],
[
"Greljo",
"Admir",
""
],
[
"Kamenik",
"Jernej F.",
""
],
[
"Kosnik",
"Nejc",
""
],
[
"Nisandzic",
"Ivan",
""
]
] |
We speculate about the possible interpretations of the recently observed excess in the $h \to \tau \mu$ decay. We derive a robust lower bound on the Higgs boson coupling strength to a tau and a muon, even in presence of the most general new physics affecting other Higgs properties. Then we reevaluate complementary indirect constraints coming from low energy observables as well as from theoretical considerations. In particular, the tentative signal should lead to $\tau \to \mu \gamma$ at rates which could be observed at Belle II. In turn we show that, barring fine-tuned cancellations, the effect can only be accommodated within models with an extended scalar sector. These general conclusions are demonstrated using a number of explicit new physics models. Finally we show how, given the $h \to \tau \mu$ signal, the current and future searches for $\mu \to e \gamma$ and $\mu \to e$ nuclear conversions unambiguously constrain the allowed rates for $h \to \tau e$.
|
2306.07671
|
Newton Nath
|
Eligio Lisi, Antonio Marrone, Newton Nath
|
Interplay between non-interfering neutrino exchange mechanisms and
nuclear matrix elements in $0\nu\beta\beta$ decay
|
20 pages, 9 figures, discussion and references added, conclusion
unchanged
|
Phys. Rev. D 108, 055023 (2023)
|
10.1103/PhysRevD.108.055023
| null |
hep-ph hep-ex nucl-ex nucl-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We revisit the phenomenology of neutrinoless double beta ($0\nu\beta\beta$)
decay mediated by non-interfering exchange of light and heavy Majorana
neutrinos, in the context of current and prospective ton-scale experimental
searches, as well as of recent calculations of nuclear matrix elements (NME) in
different nuclear models. We derive joint upper bounds on the light and heavy
contributions to $0\nu\beta\beta$ decay, for different sets of NME, through
separate and combined data coming from the following experiments (and
isotopes): KamLAND-Zen and EXO (Xe), GERDA, and MAJORANA (Ge) and CUORE (Te).
We further consider three proposed projects that could provide, within current
bounds, possible $0\nu\beta\beta$ decay signals at $>\!3\sigma$ level with an
exposure of 10 ton years: nEXO (Xe), LEGEND (Ge) and CUPID (Mo). Separate and
combined (Xe, Ge, Mo) signals are studied for different representative cases
and NME sets, and the conditions leading to (non)degenerate light and heavy
neutrino mechanisms are discussed. In particular, the role of heavy-to-light
NME ratios in different isotopes is highlighted through appropriate graphical
representations. By using different sets of "true" and "test" NME as a proxy
for nuclear uncertainties, it is shown that the relative contributions of light
and heavy neutrino exchange to $0\nu\beta\beta$ signals may be significantly
biased in some cases. Implications for theoretical models connecting light and
heavy Majorana neutrino masses are also briefly illustrated. These results
provide further motivations to improve NME calculations, so as to better
exploit the physics potential of future multi-isotope $0\nu\beta\beta$ searches
at the ton scale.
|
[
{
"created": "Tue, 13 Jun 2023 10:28:12 GMT",
"version": "v1"
},
{
"created": "Wed, 20 Sep 2023 14:48:19 GMT",
"version": "v2"
}
] |
2023-09-21
|
[
[
"Lisi",
"Eligio",
""
],
[
"Marrone",
"Antonio",
""
],
[
"Nath",
"Newton",
""
]
] |
We revisit the phenomenology of neutrinoless double beta ($0\nu\beta\beta$) decay mediated by non-interfering exchange of light and heavy Majorana neutrinos, in the context of current and prospective ton-scale experimental searches, as well as of recent calculations of nuclear matrix elements (NME) in different nuclear models. We derive joint upper bounds on the light and heavy contributions to $0\nu\beta\beta$ decay, for different sets of NME, through separate and combined data coming from the following experiments (and isotopes): KamLAND-Zen and EXO (Xe), GERDA, and MAJORANA (Ge) and CUORE (Te). We further consider three proposed projects that could provide, within current bounds, possible $0\nu\beta\beta$ decay signals at $>\!3\sigma$ level with an exposure of 10 ton years: nEXO (Xe), LEGEND (Ge) and CUPID (Mo). Separate and combined (Xe, Ge, Mo) signals are studied for different representative cases and NME sets, and the conditions leading to (non)degenerate light and heavy neutrino mechanisms are discussed. In particular, the role of heavy-to-light NME ratios in different isotopes is highlighted through appropriate graphical representations. By using different sets of "true" and "test" NME as a proxy for nuclear uncertainties, it is shown that the relative contributions of light and heavy neutrino exchange to $0\nu\beta\beta$ signals may be significantly biased in some cases. Implications for theoretical models connecting light and heavy Majorana neutrino masses are also briefly illustrated. These results provide further motivations to improve NME calculations, so as to better exploit the physics potential of future multi-isotope $0\nu\beta\beta$ searches at the ton scale.
|
0903.1886
|
Masashi Wakamatsu
|
M. Wakamatsu
|
Transverse momentum distributions of quarks in the nucleon from the
Chiral Quark Soliton Model
|
The version to appear in Physical Review D
|
Phys.Rev.D79:094028,2009
|
10.1103/PhysRevD.79.094028
|
OU-HET-625
|
hep-ph hep-ex nucl-ex
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We report the first calculation of the simplest but most fundamental
transverse momentum dependent (TMD) distribution of quarks in the nucleon, i.e.
the time-reversal-even unpolarized TMD quark and antiquark distribution with
isoscalar combination, within the framework of the chiral quark soliton model.
The nonperturbative account of the deformed Dirac-sea quarks within the
theoretical scheme enables us to make a reliable predictions not only for the
quark distribution but also for the antiquark distribution. We found that the
predicted average transverse momentum square $<k_\perp^2>$ of quarks and
antiquarks depends strongly on their longitudinal momentum fraction $x$, which
means that the frequently used assumption of factorization in $x$ and $k_\perp$
is significantly violated. It is also found, somewhat unexpectedly, that the
average transverse momentum square of antiquarks is considerably larger than
that of quarks.
|
[
{
"created": "Wed, 11 Mar 2009 01:06:43 GMT",
"version": "v1"
},
{
"created": "Wed, 20 May 2009 00:52:52 GMT",
"version": "v2"
}
] |
2009-07-30
|
[
[
"Wakamatsu",
"M.",
""
]
] |
We report the first calculation of the simplest but most fundamental transverse momentum dependent (TMD) distribution of quarks in the nucleon, i.e. the time-reversal-even unpolarized TMD quark and antiquark distribution with isoscalar combination, within the framework of the chiral quark soliton model. The nonperturbative account of the deformed Dirac-sea quarks within the theoretical scheme enables us to make a reliable predictions not only for the quark distribution but also for the antiquark distribution. We found that the predicted average transverse momentum square $<k_\perp^2>$ of quarks and antiquarks depends strongly on their longitudinal momentum fraction $x$, which means that the frequently used assumption of factorization in $x$ and $k_\perp$ is significantly violated. It is also found, somewhat unexpectedly, that the average transverse momentum square of antiquarks is considerably larger than that of quarks.
|
1207.6529
|
Francesco Murgia
|
M. Anselmino (1,2), M. Boglione (1,2), U. D'Alesio (3,4), E. Leader
(5), S. Melis (6), F. Murgia (4), A. Prokudin (7) ((1) University of Torino,
Italy, (2) INFN, Torino, Italy, (3) University of Cagliari, Italy, (4) INFN,
Cagliari, Italy, (5) Imperial College, London, UK, (6) ECT, Trento, Italy,
(7) JLab, Newport News, USA)
|
On the role of Collins effect in the single spin asymmetry A_N in
p(transv. polarized) p --> h X processes
|
RevTeX4, 11 pages, 6 eps figures
| null |
10.1103/PhysRevD.86.074032
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The much debated issue of the transverse single spin asymmetry A_N observed
in the inclusive large P_T production of a single hadron in pp interactions,
p(transv. polarized) p --> pion X, is considered in a TMD factorization scheme.
A previous result [1,2] stating that the maximum contribution of the Collins
effect is strongly suppressed, is revisited, correcting a numerical error. New
estimates are given, adopting the Collins functions recently extracted from
SIDIS and e+e- data, and phenomenological consequences are discussed.
|
[
{
"created": "Fri, 27 Jul 2012 12:43:18 GMT",
"version": "v1"
}
] |
2013-05-30
|
[
[
"Anselmino",
"M.",
""
],
[
"Boglione",
"M.",
""
],
[
"D'Alesio",
"U.",
""
],
[
"Leader",
"E.",
""
],
[
"Melis",
"S.",
""
],
[
"Murgia",
"F.",
""
],
[
"Prokudin",
"A.",
""
]
] |
The much debated issue of the transverse single spin asymmetry A_N observed in the inclusive large P_T production of a single hadron in pp interactions, p(transv. polarized) p --> pion X, is considered in a TMD factorization scheme. A previous result [1,2] stating that the maximum contribution of the Collins effect is strongly suppressed, is revisited, correcting a numerical error. New estimates are given, adopting the Collins functions recently extracted from SIDIS and e+e- data, and phenomenological consequences are discussed.
|
1405.4831
|
Jacobo Ruiz de Elvira
|
Thomas Cohen, Felipe J. Llanes-Estrada, J. R. Pelaez and J. Ruiz de
Elvira
|
Non-ordinary light meson couplings and the $1/N_c$ expansion
|
37 pages and 12 figures
|
Phys. Rev. D 90, 036003 (2014)
|
10.1103/PhysRevD.90.036003
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We study the large $N_c$ behavior of couplings among light meson states with
different compositions in terms of quarks and gluons. We shortly review the
most common compositions of mesons, which are of interest for the understanding
of low-lying meson resonances, namely, the ordinary quark-antiquark states as
well as the non-ordinary, glueball, tetraquark, etc. We dedicate special
attention to Jaffe's generalization of the tetraquark with $N_c-1$ $q\bar{q}$
pairs, that is the only type of state we have identified, whose width does not
necessarily vanish with $N_c$, while it does decouple exponentially with $N_c$
from the $\pi\pi$ channel, so that is weakly coupled to the meson-meson system.
|
[
{
"created": "Mon, 19 May 2014 18:40:19 GMT",
"version": "v1"
}
] |
2014-08-20
|
[
[
"Cohen",
"Thomas",
""
],
[
"Llanes-Estrada",
"Felipe J.",
""
],
[
"Pelaez",
"J. R.",
""
],
[
"de Elvira",
"J. Ruiz",
""
]
] |
We study the large $N_c$ behavior of couplings among light meson states with different compositions in terms of quarks and gluons. We shortly review the most common compositions of mesons, which are of interest for the understanding of low-lying meson resonances, namely, the ordinary quark-antiquark states as well as the non-ordinary, glueball, tetraquark, etc. We dedicate special attention to Jaffe's generalization of the tetraquark with $N_c-1$ $q\bar{q}$ pairs, that is the only type of state we have identified, whose width does not necessarily vanish with $N_c$, while it does decouple exponentially with $N_c$ from the $\pi\pi$ channel, so that is weakly coupled to the meson-meson system.
|
1712.01310
|
Roberto Franceschini
|
Roberto Franceschini, Giuliano Panico, Alex Pomarol, Francesco Riva
and Andrea Wulzer
|
Electroweak Precision Tests in High-Energy Diboson Processes
|
35 pages, 8 Figures, Fig.7 corrected
| null |
10.1007/JHEP02(2018)111
|
CERN-TH-2017-252, RM3-TH/17-1
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
A promising avenue to perform precision tests of the SM at the LHC is to
measure differential cross-sections at high invariant mass, exploiting in this
way the growth with the energy of the corrections induced by heavy new physics.
We classify the leading growing-with-energy effects in longitudinal diboson and
in associated Higgs production processes, showing that they can be encapsulated
in four real "high-energy primary" parameters. We assess the reach on these
parameters at the LHC and at future hadronic colliders, focusing in particular
on the fully leptonic $WZ$ channel that appears particularly promising. The
reach is found to be superior to existing constraints by one order of
magnitude, providing a test of the SM electroweak sector at the per-mille
level, in competition with LEP bounds. Unlike LHC Run-1 bounds, which only
apply to new physics effects that are much larger than the SM in the
high-energy tail of the distributions, the probe we study applies to a wider
class of new physics scenarios where such large departures are not expected.
|
[
{
"created": "Mon, 4 Dec 2017 19:19:00 GMT",
"version": "v1"
},
{
"created": "Fri, 8 Jun 2018 08:31:30 GMT",
"version": "v2"
}
] |
2018-06-11
|
[
[
"Franceschini",
"Roberto",
""
],
[
"Panico",
"Giuliano",
""
],
[
"Pomarol",
"Alex",
""
],
[
"Riva",
"Francesco",
""
],
[
"Wulzer",
"Andrea",
""
]
] |
A promising avenue to perform precision tests of the SM at the LHC is to measure differential cross-sections at high invariant mass, exploiting in this way the growth with the energy of the corrections induced by heavy new physics. We classify the leading growing-with-energy effects in longitudinal diboson and in associated Higgs production processes, showing that they can be encapsulated in four real "high-energy primary" parameters. We assess the reach on these parameters at the LHC and at future hadronic colliders, focusing in particular on the fully leptonic $WZ$ channel that appears particularly promising. The reach is found to be superior to existing constraints by one order of magnitude, providing a test of the SM electroweak sector at the per-mille level, in competition with LEP bounds. Unlike LHC Run-1 bounds, which only apply to new physics effects that are much larger than the SM in the high-energy tail of the distributions, the probe we study applies to a wider class of new physics scenarios where such large departures are not expected.
|
hep-ph/0005261
|
Lisi Eligio
|
G.L. Fogli (Bari U. & INFN, Bari), E. Lisi (Bari U. & INFN, Bari), D.
Montanino (Lecce U.), A. Palazzo (Bari U. & INFN, Bari)
|
Quasivacuum solar neutrino oscillations
|
17 pages (RevTeX) + 8 figures (PostScript). Final version, to appear
in Phys. Rev. D
|
Phys.Rev.D62:113004,2000
|
10.1103/PhysRevD.62.113004
| null |
hep-ph astro-ph hep-ex
| null |
We discuss in detail solar neutrino oscillations with \delta m^2/E in the
range [10^-10,10^-7] eV^2/MeV. In this range, which interpolates smoothly
between the so-called ``just-so'' and ``Mikheyev-Smirnov-Wolfenstein''
oscillation regimes, neutrino flavor transitions are increasingly affected by
matter effects as \delta m^2/E increases. As a consequence, the usual vacuum
approximation has to be improved through the matter-induced corrections,
leading to a ``quasi-vacuum'' oscillation regime. We perform accurate numerical
calculations of such corrections, using both the true solar density profile and
its exponential approximation. Matter effects are shown to be somewhat
overestimated in the latter case. We also discuss the role of Earth crossing
and of energy smearing. Prescriptions are given to implement the leading
corrections in the quasi-vacuum oscillation range. Finally, the results are
applied to a global analysis of solar nu data in a three-flavor framework.
|
[
{
"created": "Thu, 25 May 2000 17:37:45 GMT",
"version": "v1"
},
{
"created": "Tue, 19 Sep 2000 11:50:13 GMT",
"version": "v2"
}
] |
2009-10-07
|
[
[
"Fogli",
"G. L.",
"",
"Bari U. & INFN, Bari"
],
[
"Lisi",
"E.",
"",
"Bari U. & INFN, Bari"
],
[
"Montanino",
"D.",
"",
"Lecce U."
],
[
"Palazzo",
"A.",
"",
"Bari U. & INFN, Bari"
]
] |
We discuss in detail solar neutrino oscillations with \delta m^2/E in the range [10^-10,10^-7] eV^2/MeV. In this range, which interpolates smoothly between the so-called ``just-so'' and ``Mikheyev-Smirnov-Wolfenstein'' oscillation regimes, neutrino flavor transitions are increasingly affected by matter effects as \delta m^2/E increases. As a consequence, the usual vacuum approximation has to be improved through the matter-induced corrections, leading to a ``quasi-vacuum'' oscillation regime. We perform accurate numerical calculations of such corrections, using both the true solar density profile and its exponential approximation. Matter effects are shown to be somewhat overestimated in the latter case. We also discuss the role of Earth crossing and of energy smearing. Prescriptions are given to implement the leading corrections in the quasi-vacuum oscillation range. Finally, the results are applied to a global analysis of solar nu data in a three-flavor framework.
|
hep-ph/0204217
|
Joaquim Inacio da Silva Marcos
|
Joaquim I. Silva-Marcos
|
Symmetries, Large Leptonic Mixing and a Fourth Generation
|
6 pages, ReVTeX, no figures
|
JHEP 0212:036,2002
|
10.1088/1126-6708/2002/12/036
| null |
hep-ph
| null |
We show that large leptonic mixing occurs most naturally in the framework of
the Sandard Model just by adding a fourth generation. One can then construct a
small $Z_4$ discrete symmetry, instead of the large $S_{4L}\times S_{4R}$,
which requires that the neutrino as well as the charged lepton mass matrices be
proportional to a $4\times 4$ democratic mass matrix, where all entries are
equal to unity. Without considering the see-saw mechanism, or other more
elaborate extensions of the SM, and contrary to the case with only 3
generations, large leptonic mixing is obtained when the symmetry is broken.
|
[
{
"created": "Thu, 18 Apr 2002 11:50:13 GMT",
"version": "v1"
},
{
"created": "Wed, 19 Jun 2002 09:49:37 GMT",
"version": "v2"
}
] |
2010-02-03
|
[
[
"Silva-Marcos",
"Joaquim I.",
""
]
] |
We show that large leptonic mixing occurs most naturally in the framework of the Sandard Model just by adding a fourth generation. One can then construct a small $Z_4$ discrete symmetry, instead of the large $S_{4L}\times S_{4R}$, which requires that the neutrino as well as the charged lepton mass matrices be proportional to a $4\times 4$ democratic mass matrix, where all entries are equal to unity. Without considering the see-saw mechanism, or other more elaborate extensions of the SM, and contrary to the case with only 3 generations, large leptonic mixing is obtained when the symmetry is broken.
|
2108.04027
|
Felipe J. Llanes-Estrada
|
Eva Lope-Oter and Felipe J. Llanes-Estrada (Univ. Complutense de
Madrid)
|
Unbiased interpolated neutron-star EoS at finite T for modified gravity
studies
|
7 pages, 10 plots
| null |
10.1140/epja/s10050-021-00656-9
| null |
hep-ph gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Neutron stars and their mergers provide the highest-density regime in which
Einstein's equations in full (with a matter source) can be tested against
modified theories of gravity. But doing so requires a priori knowledge of the
Equation of State from nuclear and hadron physics, where no contamination from
computations of astrophysics observables within General Relativity has been
built in. We extend the nEoS uncertainty bands, useful for this very purpose,
to finite (but small) temperatures up to 30 MeV, given that the necessary
computations in ChPT and in pQCD at already available in the literature. The
temperature-dependent band boundaries will be provided through the COMPOSE
repository and our own website.
|
[
{
"created": "Sat, 31 Jul 2021 21:15:21 GMT",
"version": "v1"
}
] |
2022-02-09
|
[
[
"Lope-Oter",
"Eva",
"",
"Univ. Complutense de\n Madrid"
],
[
"Llanes-Estrada",
"Felipe J.",
"",
"Univ. Complutense de\n Madrid"
]
] |
Neutron stars and their mergers provide the highest-density regime in which Einstein's equations in full (with a matter source) can be tested against modified theories of gravity. But doing so requires a priori knowledge of the Equation of State from nuclear and hadron physics, where no contamination from computations of astrophysics observables within General Relativity has been built in. We extend the nEoS uncertainty bands, useful for this very purpose, to finite (but small) temperatures up to 30 MeV, given that the necessary computations in ChPT and in pQCD at already available in the literature. The temperature-dependent band boundaries will be provided through the COMPOSE repository and our own website.
|
1507.03943
|
Ernest Ma
|
Ernest Ma, Nicholas Pollard, Rahul Srivastava, and Mohammadreza Zakeri
|
Gauge $B-L$ Model with Residual $Z_3$ Symmetry
|
11 pages, 2 figures, references added, fig.1 corrected
| null |
10.1016/j.physletb.2015.09.010
|
UCRHEP-T554 (July 2015)
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We study a gauge $B-L$ extension of the standard model of quarks and leptons
with unconventional charges for the singlet right-handed neutrinos, and extra
singlet scalars, such that a residual $Z_3$ symmetry remains after the
spontaneous breaking of $B-L$. We discuss the phenomenological consequences of
this scenario, including the possibility of long-lived self-interacting dark
matter and $Z'$ collider signatures.
|
[
{
"created": "Tue, 14 Jul 2015 17:35:15 GMT",
"version": "v1"
},
{
"created": "Thu, 16 Jul 2015 17:33:48 GMT",
"version": "v2"
}
] |
2015-09-16
|
[
[
"Ma",
"Ernest",
""
],
[
"Pollard",
"Nicholas",
""
],
[
"Srivastava",
"Rahul",
""
],
[
"Zakeri",
"Mohammadreza",
""
]
] |
We study a gauge $B-L$ extension of the standard model of quarks and leptons with unconventional charges for the singlet right-handed neutrinos, and extra singlet scalars, such that a residual $Z_3$ symmetry remains after the spontaneous breaking of $B-L$. We discuss the phenomenological consequences of this scenario, including the possibility of long-lived self-interacting dark matter and $Z'$ collider signatures.
|
2205.00321
|
Werner Porod
|
Werner Porod
|
LHC phenomenology of unusual top partners in composite Higgs models
|
Contribution to the Corfu Summer Institute 2021 "School and Workshops
on Elementary Particle Physics and Gravity"
| null | null | null |
hep-ph
|
http://creativecommons.org/licenses/by/4.0/
|
Composite Higgs models with a fermionic UV completion can contain additional
colored states beside the usual top-partners. We focus here on a model which
contains in addition SU(3) color octet top partners as well as color singlet
ones. The latter can in principle serve as a dark matter candidate. We consider
a particular composite Higgs model which contains SU(3) color octet top
partners besides the usually considered triplet representations. Moreover,
color singlet top partners are present as well which can in principle serve as
dark matter candidates. We investigate the LHC phenomenology of these unusual
top partners. Some of these states could at first glance be confused with
gluinos predicted in supersymmetric models.
|
[
{
"created": "Sat, 30 Apr 2022 18:36:46 GMT",
"version": "v1"
}
] |
2022-05-03
|
[
[
"Porod",
"Werner",
""
]
] |
Composite Higgs models with a fermionic UV completion can contain additional colored states beside the usual top-partners. We focus here on a model which contains in addition SU(3) color octet top partners as well as color singlet ones. The latter can in principle serve as a dark matter candidate. We consider a particular composite Higgs model which contains SU(3) color octet top partners besides the usually considered triplet representations. Moreover, color singlet top partners are present as well which can in principle serve as dark matter candidates. We investigate the LHC phenomenology of these unusual top partners. Some of these states could at first glance be confused with gluinos predicted in supersymmetric models.
|
1208.5502
|
Skokov Vladimir
|
Adam Bzdak and Vladimir Skokov
|
Anisotropy of photon production: Initial eccentricity or magnetic field
|
4 pages, 3 figures; version accepted for publication: discussions
extended, MC calculations added
|
Phys. Rev. Lett. 110, 192301 (2013)
|
10.1103/PhysRevLett.110.192301
| null |
hep-ph nucl-ex nucl-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Recent measurements of the azimuthal anisotropy of direct photons in
heavy-ion collisions at the energies of RHIC show that it is of the same order
as the hadronic one. This finding appears to contradict the expected dominance
of photon production from a quark-gluon plasma at an early stage of a heavy-ion
collision. A possible explanation of the strong azimuthal anisotropy of the
photons, given recently, is based on the presence of a large magnetic field in
the early phase of a collision. In this letter, we propose a method to
experimentally measure the degree to which a magnetic field in heavy-ion
collisions is responsible for the observed anisotropy of photon production. The
experimental test proposed in this letter may potentially change our
understanding of the non-equilibrium stage and possible thermalization in
heavy-ion collisions.
|
[
{
"created": "Mon, 27 Aug 2012 20:50:44 GMT",
"version": "v1"
},
{
"created": "Fri, 31 Aug 2012 15:00:19 GMT",
"version": "v2"
},
{
"created": "Sat, 11 May 2013 14:31:37 GMT",
"version": "v3"
}
] |
2015-06-11
|
[
[
"Bzdak",
"Adam",
""
],
[
"Skokov",
"Vladimir",
""
]
] |
Recent measurements of the azimuthal anisotropy of direct photons in heavy-ion collisions at the energies of RHIC show that it is of the same order as the hadronic one. This finding appears to contradict the expected dominance of photon production from a quark-gluon plasma at an early stage of a heavy-ion collision. A possible explanation of the strong azimuthal anisotropy of the photons, given recently, is based on the presence of a large magnetic field in the early phase of a collision. In this letter, we propose a method to experimentally measure the degree to which a magnetic field in heavy-ion collisions is responsible for the observed anisotropy of photon production. The experimental test proposed in this letter may potentially change our understanding of the non-equilibrium stage and possible thermalization in heavy-ion collisions.
|
hep-ph/0506291
|
Charanjit S. Aulakh
|
Charanjit S. Aulakh
|
MSGUTs from Germ to Bloom : towards Falsifiability and Beyond
|
Typos corrected,5 references added, discussion of origin of fermion
mass matrix phase freedom in FM fits improved, proposal for route to string
based SO(10) GUTs with R parity and Seesaw added in discussion section
| null | null | null |
hep-ph
| null |
We review the development of minimal renormalizable SO(10) Susy GUTs. Using
our $SO(10) \to G_{Pati-Salam} $ label decomposition we calculated the complete
GUT scale spectra and couplings and the threshold effects therefrom. The
corrections to $\alpha_G, Sin^2{\theta}_W $ and $ M_X $ are sensitive functions
of the single parameter $\xi$ that controls symmetry breaking and slow funtions
of the others. Scans of the parameter space to identify regions compatible with
gauge unification are shown. The tight connection between the phenomenology of
neutrino oscillations and exotic ($\Delta B\neq 0 $) processes predicted by
Susy SO(10) GUTs is discussed in the context of the recent successful fits of
all available fermion mass/mixing data using the ${\bf{10 \oplus {\bar
{126}}}}$ Higgs representations and Type I/II seesaw mechanisms for neutrino
mass. We emphasize that {\it{the true output of these calculations should be
regarded as the unitary matrices that specify the orientation of the embedding
of the MSSM within the MSGUT}}. Fermion Mass fitting constraints combined with
GUT spectra can falsify/constrain the MSGUT and its near relatives. An initial
survey indicates that Type I Seesaw neutrino masses dominate Type II and both
are too small in the perturbative MSGUT even when the mixing and mass squared
splitting ratios are as per data. This motivates a detailed study of the MSGUT
constraints using the outputs of the fitting of fermion data, as well as
consideration of modifications/extensions of the MSGUT scenario.
|
[
{
"created": "Tue, 28 Jun 2005 12:16:16 GMT",
"version": "v1"
},
{
"created": "Mon, 18 Jul 2005 19:55:08 GMT",
"version": "v2"
}
] |
2007-05-23
|
[
[
"Aulakh",
"Charanjit S.",
""
]
] |
We review the development of minimal renormalizable SO(10) Susy GUTs. Using our $SO(10) \to G_{Pati-Salam} $ label decomposition we calculated the complete GUT scale spectra and couplings and the threshold effects therefrom. The corrections to $\alpha_G, Sin^2{\theta}_W $ and $ M_X $ are sensitive functions of the single parameter $\xi$ that controls symmetry breaking and slow funtions of the others. Scans of the parameter space to identify regions compatible with gauge unification are shown. The tight connection between the phenomenology of neutrino oscillations and exotic ($\Delta B\neq 0 $) processes predicted by Susy SO(10) GUTs is discussed in the context of the recent successful fits of all available fermion mass/mixing data using the ${\bf{10 \oplus {\bar {126}}}}$ Higgs representations and Type I/II seesaw mechanisms for neutrino mass. We emphasize that {\it{the true output of these calculations should be regarded as the unitary matrices that specify the orientation of the embedding of the MSSM within the MSGUT}}. Fermion Mass fitting constraints combined with GUT spectra can falsify/constrain the MSGUT and its near relatives. An initial survey indicates that Type I Seesaw neutrino masses dominate Type II and both are too small in the perturbative MSGUT even when the mixing and mass squared splitting ratios are as per data. This motivates a detailed study of the MSGUT constraints using the outputs of the fitting of fermion data, as well as consideration of modifications/extensions of the MSGUT scenario.
|
hep-ph/0507243
|
Artem Lipatov
|
A.V. Lipatov, N.P. Zotov
|
Prompt photon hadroproduction at high energies in the k_T-factorization
approach
|
27 pages, 13 figures
|
J.Phys.G34:219,2007
|
10.1088/0954-3899/34/2/005
| null |
hep-ph
| null |
We consider the prompt photon production at high energy hadron colliders in
the framework of k_T-factorization approach. The unintegrated quark and gluon
distributions in a proton are determined using the Kimber-Martin-Ryskin
prescription. The conservative error analisys is performed. We investigate both
inclusive prompt photon and prompt photon and associated muon production rates.
In Standard Model such events come mainly due to Compton scattering process
where the final heavy (charm or bottom) quark produces a muon. The theoretical
results are compared with recent experimental data taken by the D0 and CDF
collaborations at Fermilab Tevatron. Our analysis also covers the azimuthal
correlations between produced prompt photon and muon which can provide an
important information about non-collinear parton evolution in a proton.
Finally, we extrapolate the theoretical predictions to CERN LHC energies.
|
[
{
"created": "Wed, 20 Jul 2005 12:15:03 GMT",
"version": "v1"
}
] |
2011-03-23
|
[
[
"Lipatov",
"A. V.",
""
],
[
"Zotov",
"N. P.",
""
]
] |
We consider the prompt photon production at high energy hadron colliders in the framework of k_T-factorization approach. The unintegrated quark and gluon distributions in a proton are determined using the Kimber-Martin-Ryskin prescription. The conservative error analisys is performed. We investigate both inclusive prompt photon and prompt photon and associated muon production rates. In Standard Model such events come mainly due to Compton scattering process where the final heavy (charm or bottom) quark produces a muon. The theoretical results are compared with recent experimental data taken by the D0 and CDF collaborations at Fermilab Tevatron. Our analysis also covers the azimuthal correlations between produced prompt photon and muon which can provide an important information about non-collinear parton evolution in a proton. Finally, we extrapolate the theoretical predictions to CERN LHC energies.
|
2112.09814
|
Nikita Blinov
|
Nikita Blinov, Elizabeth Kowalczyk, Margaret Wynne
|
Axion-like Particle Searches at DarkQuest
|
39 pages + appendices, 18 figures. References added; matches
published version
|
JHEP02(2022)036
|
10.1007/JHEP02(2022)036
|
FERMILAB-PUB-21-749-V
|
hep-ph hep-ex
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Axion-like particles (ALPs) interacting with the Standard Model can be
abundantly produced in proton beam fixed-target experiments. Looking for their
displaced decays is therefore an effective search strategy for ALPs with a mass
in the MeV to GeV range. Focusing on the benchmark models where the ALP
interacts dominantly with photons or gluons, we show that the proposed
DarkQuest experiment at Fermilab will be able to test parameter space which has
been previously inaccessible. We pay particular attention to the
self-consistency of gluon-coupled ALP production and decay calculations, which
has been recently shown to be a problem in many existing predictions. We also
apply these results to explore existing constraints in the ALP parameter space.
|
[
{
"created": "Sat, 18 Dec 2021 01:03:57 GMT",
"version": "v1"
},
{
"created": "Sun, 26 Dec 2021 06:03:39 GMT",
"version": "v2"
},
{
"created": "Sun, 6 Feb 2022 06:16:04 GMT",
"version": "v3"
}
] |
2022-02-08
|
[
[
"Blinov",
"Nikita",
""
],
[
"Kowalczyk",
"Elizabeth",
""
],
[
"Wynne",
"Margaret",
""
]
] |
Axion-like particles (ALPs) interacting with the Standard Model can be abundantly produced in proton beam fixed-target experiments. Looking for their displaced decays is therefore an effective search strategy for ALPs with a mass in the MeV to GeV range. Focusing on the benchmark models where the ALP interacts dominantly with photons or gluons, we show that the proposed DarkQuest experiment at Fermilab will be able to test parameter space which has been previously inaccessible. We pay particular attention to the self-consistency of gluon-coupled ALP production and decay calculations, which has been recently shown to be a problem in many existing predictions. We also apply these results to explore existing constraints in the ALP parameter space.
|
hep-ph/9711249
|
Steen Hannestad
|
S. Hannestad
|
Tau Neutrino Decays and Big Bang Nucleosynthesis
|
7 pages RevTeX, 6 figures. To be published in Phys. Rev. D
|
Phys.Rev. D57 (1998) 2213-2218
|
10.1103/PhysRevD.57.2213
| null |
hep-ph astro-ph
| null |
We investigate the non-radiative decay during nucleosynthesis of a massive
tau neutrino with mass 0.1 - 1 MeV into an electron neutrino and a scalar or
pseudoscalar particle, $\phi$. The full Boltzmann equation is used and shown to
give markedly different results than the usual non-relativistic formalism for
relativistic or semi-relativistic neutrino decays. Indeed, the region we
investigate is where the formalism that has previously been applied to solving
this problem is expected to break down. We also compare the nucleosynthesis
predictions from this scenario with results from the standard model and with
some of the available observational determinations of the primordial
abundances. It is found that for relativistic or semi-relativistic decays the
helium abundance can be significantly lowered without changing other light
element abundances. Since a problem with the standard model of Big Bang
nucleosynthesis is that helium appears to be overproduced, a decay of the type
we discuss can be a possible solution.
|
[
{
"created": "Thu, 6 Nov 1997 09:33:03 GMT",
"version": "v1"
}
] |
2009-10-30
|
[
[
"Hannestad",
"S.",
""
]
] |
We investigate the non-radiative decay during nucleosynthesis of a massive tau neutrino with mass 0.1 - 1 MeV into an electron neutrino and a scalar or pseudoscalar particle, $\phi$. The full Boltzmann equation is used and shown to give markedly different results than the usual non-relativistic formalism for relativistic or semi-relativistic neutrino decays. Indeed, the region we investigate is where the formalism that has previously been applied to solving this problem is expected to break down. We also compare the nucleosynthesis predictions from this scenario with results from the standard model and with some of the available observational determinations of the primordial abundances. It is found that for relativistic or semi-relativistic decays the helium abundance can be significantly lowered without changing other light element abundances. Since a problem with the standard model of Big Bang nucleosynthesis is that helium appears to be overproduced, a decay of the type we discuss can be a possible solution.
|
1701.01080
|
Hiroshi Okada
|
Kingman Cheung, Takaaki Nomura, Hiroshi Okada
|
A Three-loop Neutrino Model with Leptoquark Triplet Scalars
|
16 pages, 3 figures, 2 tables, accepted version for publication in
Physics Letters B
| null |
10.1016/j.physletb.2017.03.021
|
KIAS-P17002
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We propose a three-loop neutrino mass model with a few leptoquark scalars in
$SU(2)_L$-triplet form, through which we can explain the anomaly of $B \to
K^{(*)} \mu^+ \mu^-$, a sizable muon $g-2$ and a bosonic dark matter candidate,
and at the same time satisfying all the constraints from lepton flavor
violations. We perform global numerical analyses and show the allowed regions,
in which we find somewhat restricted parameter space, such as the mass of dark
matter candidate and various components of the Yukawa couplings in the model.
|
[
{
"created": "Wed, 4 Jan 2017 17:16:30 GMT",
"version": "v1"
},
{
"created": "Mon, 13 Mar 2017 07:33:09 GMT",
"version": "v2"
}
] |
2017-03-22
|
[
[
"Cheung",
"Kingman",
""
],
[
"Nomura",
"Takaaki",
""
],
[
"Okada",
"Hiroshi",
""
]
] |
We propose a three-loop neutrino mass model with a few leptoquark scalars in $SU(2)_L$-triplet form, through which we can explain the anomaly of $B \to K^{(*)} \mu^+ \mu^-$, a sizable muon $g-2$ and a bosonic dark matter candidate, and at the same time satisfying all the constraints from lepton flavor violations. We perform global numerical analyses and show the allowed regions, in which we find somewhat restricted parameter space, such as the mass of dark matter candidate and various components of the Yukawa couplings in the model.
|
hep-ph/0111471
|
Gabriella Pasztor
|
Gabriella Pasztor (CERN), Maxim Perelstein (LBL, Berkeley)
|
Exploring New Physics Through Contact Interactions in Lepton Pair
Production at a Linear Collider
|
Contributed to APS / DPF / DPB Summer Study on the Future of Particle
Physics (Snowmass 2001), Snowmass, Colorado, 30 Jun - 21 Jul 2001
|
eConf C010630 (2001) P315
| null |
LBNL-49222
|
hep-ph
| null |
If a contact interaction type correction to a Standard Model process is
observed, studying its detailed properties can provide information on the
fundamental physics responsible for it. Assuming that such a correction has
been observed in lepton pair production at a 500 GeV - 1 TeV linear collider,
we consider a few possible models that could explain it, such as theories with
large and TeV-scale extra dimensions and models with lepton compositeness. We
show that using the measured cross-sections and angular distributions, these
models can be distinguished with a high degree of confidence.
|
[
{
"created": "Fri, 30 Nov 2001 16:03:56 GMT",
"version": "v1"
},
{
"created": "Tue, 4 Dec 2001 18:41:11 GMT",
"version": "v2"
}
] |
2007-05-23
|
[
[
"Pasztor",
"Gabriella",
"",
"CERN"
],
[
"Perelstein",
"Maxim",
"",
"LBL, Berkeley"
]
] |
If a contact interaction type correction to a Standard Model process is observed, studying its detailed properties can provide information on the fundamental physics responsible for it. Assuming that such a correction has been observed in lepton pair production at a 500 GeV - 1 TeV linear collider, we consider a few possible models that could explain it, such as theories with large and TeV-scale extra dimensions and models with lepton compositeness. We show that using the measured cross-sections and angular distributions, these models can be distinguished with a high degree of confidence.
|
1511.02886
|
Giulia Zanderighi
|
Andrea Banfi, Fabrizio Caola, Fr\'ed\'eric A. Dreyer, Pier F. Monni,
Gavin P. Salam, Giulia Zanderighi, Falko Dulat
|
Jet-vetoed Higgs cross section in gluon fusion at N3LO+NNLL with small-R
resummation
|
30 pages, 16 figures
| null |
10.1007/JHEP04(2016)049
|
CERN-PH-TH-2015-261, OUTP-15-29P
|
hep-ph hep-ex
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We present new results for the jet-veto efficiency and zero-jet cross section
in Higgs production through gluon fusion. We incorporate the N$^3$LO
corrections to the total cross section, the NNLO corrections to the 1-jet rate,
NNLL resummation for the jet $p_t$ and LL resummation for the jet radius
dependence. Our results include known finite-mass corrections and are obtained
using the jet-veto efficiency method, updated relative to earlier work to take
into account what has been learnt from the new precision calculations that we
include. For 13 TeV collisions and using our default choice for the
renormalisation and factorisation scales, $\mu_0=m_H/2$, the matched prediction
for the jet-veto efficiency increases the pure NNNLO prediction by about 2% and
the two have comparable uncertainties. Relative to NNLO+NNLL results, the new
prediction is 2% smaller and the uncertainty reduces from more than 10% to less
than 5%. Results are also presented for the central scale $\mu_0=m_H$.
|
[
{
"created": "Mon, 9 Nov 2015 21:08:01 GMT",
"version": "v1"
}
] |
2016-05-04
|
[
[
"Banfi",
"Andrea",
""
],
[
"Caola",
"Fabrizio",
""
],
[
"Dreyer",
"Frédéric A.",
""
],
[
"Monni",
"Pier F.",
""
],
[
"Salam",
"Gavin P.",
""
],
[
"Zanderighi",
"Giulia",
""
],
[
"Dulat",
"Falko",
""
]
] |
We present new results for the jet-veto efficiency and zero-jet cross section in Higgs production through gluon fusion. We incorporate the N$^3$LO corrections to the total cross section, the NNLO corrections to the 1-jet rate, NNLL resummation for the jet $p_t$ and LL resummation for the jet radius dependence. Our results include known finite-mass corrections and are obtained using the jet-veto efficiency method, updated relative to earlier work to take into account what has been learnt from the new precision calculations that we include. For 13 TeV collisions and using our default choice for the renormalisation and factorisation scales, $\mu_0=m_H/2$, the matched prediction for the jet-veto efficiency increases the pure NNNLO prediction by about 2% and the two have comparable uncertainties. Relative to NNLO+NNLL results, the new prediction is 2% smaller and the uncertainty reduces from more than 10% to less than 5%. Results are also presented for the central scale $\mu_0=m_H$.
|
0805.3037
|
Martyn Gigg
|
M. A. Gigg and P. Richardson
|
Simulation of Finite Width Effects in Physics Beyond the Standard Model
|
16 pages, 12 figures
| null | null |
DCPT/08/68, IPPP/08/34, CERN/PH/TH-110, MCnet/08/01
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We present a method for the inclusion of finite width effects in the
simulation of Beyond Standard Model (BSM) physics. In order to test the
validity of the method we compare our results with matrix elements for a range
of production and decay processes in the Standard Model, Minimal Supersymmetric
Standard Model (MSSM) and Minimal Universal Extra Dimensions model (MUED). This
procedure has been implemented in the Herwig++ event generator and will be
available in a forthcoming release.
|
[
{
"created": "Tue, 20 May 2008 10:16:50 GMT",
"version": "v1"
}
] |
2008-05-21
|
[
[
"Gigg",
"M. A.",
""
],
[
"Richardson",
"P.",
""
]
] |
We present a method for the inclusion of finite width effects in the simulation of Beyond Standard Model (BSM) physics. In order to test the validity of the method we compare our results with matrix elements for a range of production and decay processes in the Standard Model, Minimal Supersymmetric Standard Model (MSSM) and Minimal Universal Extra Dimensions model (MUED). This procedure has been implemented in the Herwig++ event generator and will be available in a forthcoming release.
|
2203.05753
|
Neda Razzaghi
|
N. Razzaghi, S. M. M. Rasouli, P. Parada, P. V. Moniz
|
Two-zero textures based on $A_4$ symmetry and unimodular mixing matrix
| null |
Symmetry 2022, 14(11), 2410
|
10.3390/sym14112410
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Applying the $A_4$ symmetry in the scenario of unimodular second scheme of
trimaximal $TM_2$ mixing matrix, where the charged lepton mass matrix is
diagonal and the nature of neutrinos are Majorana, we investigate and analyze
feasible two zeros neutrino mass matrices. Among the seven possible two-zero
textures with $A_4$ symmetry, we have found that only two textures, namely the
texture with $(e, e)$ and $(e,\mu)$ vanishing element of mass matrix and its
permutation, are consistent with the experimental data in the non-perturbation
method. We also obtain new significant relations between phases of our model,
namely $\rho+\sigma=\phi\pm\pi$ and $\sin^2{\theta_{13}}=\frac{2}{3}R_\nu$
where $R_\nu=\frac{\delta m^2}{\Delta m^2}$. Subsequently, by admitting the
experimental ranges of $R_\nu$, we retrieve the allowed range of the unknown
phase $\phi$. Such a procedure assist us to determine the ranges of all the
neutrino observable parameters, the masses of neutrinos, the CP-violating
phases and $J$ parameter as well as to predict the normal hierarchy for the
neutrino mass. Finally, we show that our predictions with respect to our
herewith reported specific textures are consistent with the corresponding data
reported from neutrino oscillation, cosmic microwave background and
neutrinoless double beta decay experiments.
|
[
{
"created": "Fri, 11 Mar 2022 04:50:27 GMT",
"version": "v1"
},
{
"created": "Thu, 28 Apr 2022 08:29:23 GMT",
"version": "v2"
}
] |
2022-11-22
|
[
[
"Razzaghi",
"N.",
""
],
[
"Rasouli",
"S. M. M.",
""
],
[
"Parada",
"P.",
""
],
[
"Moniz",
"P. V.",
""
]
] |
Applying the $A_4$ symmetry in the scenario of unimodular second scheme of trimaximal $TM_2$ mixing matrix, where the charged lepton mass matrix is diagonal and the nature of neutrinos are Majorana, we investigate and analyze feasible two zeros neutrino mass matrices. Among the seven possible two-zero textures with $A_4$ symmetry, we have found that only two textures, namely the texture with $(e, e)$ and $(e,\mu)$ vanishing element of mass matrix and its permutation, are consistent with the experimental data in the non-perturbation method. We also obtain new significant relations between phases of our model, namely $\rho+\sigma=\phi\pm\pi$ and $\sin^2{\theta_{13}}=\frac{2}{3}R_\nu$ where $R_\nu=\frac{\delta m^2}{\Delta m^2}$. Subsequently, by admitting the experimental ranges of $R_\nu$, we retrieve the allowed range of the unknown phase $\phi$. Such a procedure assist us to determine the ranges of all the neutrino observable parameters, the masses of neutrinos, the CP-violating phases and $J$ parameter as well as to predict the normal hierarchy for the neutrino mass. Finally, we show that our predictions with respect to our herewith reported specific textures are consistent with the corresponding data reported from neutrino oscillation, cosmic microwave background and neutrinoless double beta decay experiments.
|
2112.09140
|
Gregory Soyez
|
Frederic Dreyer, Gregory Soyez and Adam Takacs
|
Quarks and gluons in the Lund plane
|
40 pages, 11 figures
|
JHEP 08 (2022) 177
|
10.1007/JHEP08(2022)177
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Discriminating quark and gluon jets is a long-standing topic in collider
phenomenology. In this paper, we address this question using the Lund jet plane
substructure technique introduced in recent years. We present two complementary
approaches: one where the quark/gluon likelihood ratio is computed
analytically, to single-logarithmic accuracy, in perturbative QCD, and one
where the Lund declusterings are used to train a neural network. For both
approaches, we either consider only the primary Lund plane or the full
clustering tree. The analytic and machine-learning discriminants are shown to
be equivalent on a toy event sample resumming exactly leading collinear single
logarithms, where the analytic calculation corresponds to the exact likelihood
ratio. On a full Monte Carlo event sample, both approaches show a good
discriminating power, with the machine-learning models usually being superior.
We carry on a study in the asymptotic limit of large logarithm, allowing us to
gain confidence that this superior performance comes from effects that are
subleading in our analytic approach. We then compare our approach to other
quark-gluon discriminants in the literature. Finally, we study the resilience
of our quark-gluon discriminants against the details of the event sample and
observe that the analytic and machine-learning approaches show similar
behaviour.
|
[
{
"created": "Thu, 16 Dec 2021 19:00:01 GMT",
"version": "v1"
}
] |
2022-08-23
|
[
[
"Dreyer",
"Frederic",
""
],
[
"Soyez",
"Gregory",
""
],
[
"Takacs",
"Adam",
""
]
] |
Discriminating quark and gluon jets is a long-standing topic in collider phenomenology. In this paper, we address this question using the Lund jet plane substructure technique introduced in recent years. We present two complementary approaches: one where the quark/gluon likelihood ratio is computed analytically, to single-logarithmic accuracy, in perturbative QCD, and one where the Lund declusterings are used to train a neural network. For both approaches, we either consider only the primary Lund plane or the full clustering tree. The analytic and machine-learning discriminants are shown to be equivalent on a toy event sample resumming exactly leading collinear single logarithms, where the analytic calculation corresponds to the exact likelihood ratio. On a full Monte Carlo event sample, both approaches show a good discriminating power, with the machine-learning models usually being superior. We carry on a study in the asymptotic limit of large logarithm, allowing us to gain confidence that this superior performance comes from effects that are subleading in our analytic approach. We then compare our approach to other quark-gluon discriminants in the literature. Finally, we study the resilience of our quark-gluon discriminants against the details of the event sample and observe that the analytic and machine-learning approaches show similar behaviour.
|
1506.07521
|
Alexander Millar
|
Iason Baldes, Nicole F. Bell, Alexander J. Millar, Raymond R. Volkas
|
Asymmetric Dark Matter and CP Violating Scatterings in a UV Complete
Model
|
28 pages, 10 figures
|
JCAP10(2015)048
|
10.1088/1475-7516/2015/10/048
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We explore possible asymmetric dark matter models using CP violating
scatterings to generate an asymmetry. In particular, we introduce a new model,
based on DM fields coupling to the SM Higgs and lepton doublets, a neutrino
portal, and explore its UV completions. We study the CP violation and asymmetry
formation of this model, to demonstrate that it is capable of producing the
correct abundance of dark matter and the observed matter-antimatter asymmetry.
Crucial to achieving this is the introduction of interactions which violate CP
with a $T^{2}$ dependence.
|
[
{
"created": "Wed, 24 Jun 2015 20:00:31 GMT",
"version": "v1"
},
{
"created": "Tue, 1 Sep 2015 13:58:54 GMT",
"version": "v2"
}
] |
2015-10-23
|
[
[
"Baldes",
"Iason",
""
],
[
"Bell",
"Nicole F.",
""
],
[
"Millar",
"Alexander J.",
""
],
[
"Volkas",
"Raymond R.",
""
]
] |
We explore possible asymmetric dark matter models using CP violating scatterings to generate an asymmetry. In particular, we introduce a new model, based on DM fields coupling to the SM Higgs and lepton doublets, a neutrino portal, and explore its UV completions. We study the CP violation and asymmetry formation of this model, to demonstrate that it is capable of producing the correct abundance of dark matter and the observed matter-antimatter asymmetry. Crucial to achieving this is the introduction of interactions which violate CP with a $T^{2}$ dependence.
|
1003.2841
|
Shinya Matsuzaki
|
Kazumoto Haba, Shinya Matsuzaki, and Koichi Yamawaki
|
Holographic Techni-dilaton, or Conformal Higgs
|
To appear in proceedings of SCGT09, Nagoya, Japan, 4 pages
| null | null | null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We study a holographic model dual to walking/conformal technicolor (W/C TC)
deforming a hard-wall type of bottom-up setup by including effects from
techni-gluon condensation. We calculate masses of (techni-) $\rho$ meson, $a_1$
meson, and flavor/chiral-singlet scalar meson identified with techni-dilaton
(TD)/conformal Higgs boson, as well as the $S$ parameter. It is shown that
gluon contributions and large anomalous dimension tend to decrease specifically
mass of the TD. In the typical model with $S \simeq 0.1$, we find $m_{\rm TD}
\simeq 600$ GeV, while $m_\rho,m_{a_1} \simeq 4 {\rm TeV}$.
|
[
{
"created": "Mon, 15 Mar 2010 02:46:30 GMT",
"version": "v1"
}
] |
2010-03-16
|
[
[
"Haba",
"Kazumoto",
""
],
[
"Matsuzaki",
"Shinya",
""
],
[
"Yamawaki",
"Koichi",
""
]
] |
We study a holographic model dual to walking/conformal technicolor (W/C TC) deforming a hard-wall type of bottom-up setup by including effects from techni-gluon condensation. We calculate masses of (techni-) $\rho$ meson, $a_1$ meson, and flavor/chiral-singlet scalar meson identified with techni-dilaton (TD)/conformal Higgs boson, as well as the $S$ parameter. It is shown that gluon contributions and large anomalous dimension tend to decrease specifically mass of the TD. In the typical model with $S \simeq 0.1$, we find $m_{\rm TD} \simeq 600$ GeV, while $m_\rho,m_{a_1} \simeq 4 {\rm TeV}$.
|
1604.08082
|
Alexandre Deur
|
A. Deur, S. J. Brodsky and G. F. de Teramond
|
The QCD Running Coupling
|
Invited review article for Progress in Particle and Nuclear Physics.
195 pages, 18 figures. V3: Minor corrections and addenda compared to V1 and
V2. V4: typo fixed in Eq. (3.21). V5: corrected a sign typo in Eqs. (3.27,
3.32, 3.33 and 3.40)
|
Prog. Part. Nuc. Phys. 90 1 (2016)
|
10.1016/j.ppnp.2016.04.003
|
JLAB-PHY-16-2199, SLAC-PUB-16448, DOE/OR/23177-3645
|
hep-ph
|
http://creativecommons.org/licenses/by/4.0/
|
We review the present knowledge for $\alpha_s$, the fundamental coupling
underlying the interactions of quarks and gluons in QCD. The dependence of
$\alpha_s(Q^2)$ on momentum transfer $Q$ encodes the underlying dynamics of
hadron physics -from color confinement in the infrared domain to asymptotic
freedom at short distances. We review constraints on $\alpha_s(Q^2)$ at high
$Q^2$, as predicted by perturbative QCD, and its analytic behavior at small
$Q^2$, based on models of nonperturbative dynamics. In the introductory part of
this review, we explain the phenomenological meaning of $\alpha_s$, the reason
for its running, and the challenges facing a complete understanding of its
analytic behavior in the infrared domain. In the second, more technical, part
of the review, we discuss the behavior of $\alpha_s(Q^2)$ in the high $Q^2$
domain of QCD. We review how $\alpha_s$ is defined, including its
renormalization scheme dependence, the definition of its renormalization scale,
the utility of effective charges, as well as Commensurate Scale Relations which
connect the various definitions of $\alpha_s$ without renormalization-scale
ambiguity. We also report recent measurements and theoretical analyses which
have led to precise QCD predictions at high energy. In the last part of the
review, we discuss the challenge of understanding the analytic behavior
$\alpha_s(Q^2)$ in the infrared domain. We also review important methods for
computing $\alpha_s$, including lattice QCD, the Schwinger-Dyson equations, the
Gribov-Zwanziger analysis and light-front holographic QCD. After describing
these approaches and enumerating their conflicting predictions, we discuss the
origin of these discrepancies and how to remedy them. Our aim is not only to
review the advances in this difficult area, but also to suggest what could be
an optimal definition of $\alpha_s$ in order to bring better unity to the
subject.
|
[
{
"created": "Wed, 27 Apr 2016 14:20:07 GMT",
"version": "v1"
},
{
"created": "Fri, 3 Jun 2016 22:19:38 GMT",
"version": "v2"
},
{
"created": "Mon, 15 Aug 2016 12:29:59 GMT",
"version": "v3"
},
{
"created": "Thu, 10 Sep 2020 10:59:52 GMT",
"version": "v4"
},
{
"created": "Thu, 4 May 2023 15:27:57 GMT",
"version": "v5"
}
] |
2023-05-05
|
[
[
"Deur",
"A.",
""
],
[
"Brodsky",
"S. J.",
""
],
[
"de Teramond",
"G. F.",
""
]
] |
We review the present knowledge for $\alpha_s$, the fundamental coupling underlying the interactions of quarks and gluons in QCD. The dependence of $\alpha_s(Q^2)$ on momentum transfer $Q$ encodes the underlying dynamics of hadron physics -from color confinement in the infrared domain to asymptotic freedom at short distances. We review constraints on $\alpha_s(Q^2)$ at high $Q^2$, as predicted by perturbative QCD, and its analytic behavior at small $Q^2$, based on models of nonperturbative dynamics. In the introductory part of this review, we explain the phenomenological meaning of $\alpha_s$, the reason for its running, and the challenges facing a complete understanding of its analytic behavior in the infrared domain. In the second, more technical, part of the review, we discuss the behavior of $\alpha_s(Q^2)$ in the high $Q^2$ domain of QCD. We review how $\alpha_s$ is defined, including its renormalization scheme dependence, the definition of its renormalization scale, the utility of effective charges, as well as Commensurate Scale Relations which connect the various definitions of $\alpha_s$ without renormalization-scale ambiguity. We also report recent measurements and theoretical analyses which have led to precise QCD predictions at high energy. In the last part of the review, we discuss the challenge of understanding the analytic behavior $\alpha_s(Q^2)$ in the infrared domain. We also review important methods for computing $\alpha_s$, including lattice QCD, the Schwinger-Dyson equations, the Gribov-Zwanziger analysis and light-front holographic QCD. After describing these approaches and enumerating their conflicting predictions, we discuss the origin of these discrepancies and how to remedy them. Our aim is not only to review the advances in this difficult area, but also to suggest what could be an optimal definition of $\alpha_s$ in order to bring better unity to the subject.
|
hep-ph/9502202
|
Lyubovitskij Valery
|
M.A.Ivanov and V.E.Lyubovitskij
|
Isgur-Wise Function and Observables of $\Lambda_b$ Baryon
|
9 pages, LaTeX (3 figures avaible under request)
| null | null |
Preprint JINR P2-94-325, 1994
|
hep-ph
| null |
In connection with planned experiments devoted to investigation of
semileptonic decays of beauty baryons Isgur-Wise function and observables of
$\Lambda_b$ baryon (decay rates and distributions, leptonic spectra and
asymmetry parameters) are calculated in the framework of diquark model with
taking into account of infrared regime for heavy quark.
|
[
{
"created": "Wed, 1 Feb 1995 13:25:17 GMT",
"version": "v1"
}
] |
2016-09-01
|
[
[
"Ivanov",
"M. A.",
""
],
[
"Lyubovitskij",
"V. E.",
""
]
] |
In connection with planned experiments devoted to investigation of semileptonic decays of beauty baryons Isgur-Wise function and observables of $\Lambda_b$ baryon (decay rates and distributions, leptonic spectra and asymmetry parameters) are calculated in the framework of diquark model with taking into account of infrared regime for heavy quark.
|
2111.11444
|
Juri Smirnov
|
Pouya Asadi, Tracy R. Slatyer, Juri Smirnov
|
WIMPs Without Weakness: Generalized Mass Window with Entropy Injection
|
9 pages and technical appendices
| null |
10.1103/PhysRevD.106.015012
|
MIT-CTP/5361
|
hep-ph astro-ph.CO hep-th
|
http://creativecommons.org/licenses/by/4.0/
|
We study general freeze-out scenarios where an arbitrary number of initial
and final dark matter particles participate in the number-changing freeze-out
interaction. We consider a simple sector with two particle species undergoing
such a thermal freeze-out; one of the relics is stable and gives rise to the
dark matter today, while the other one decays to the Standard Model, injecting
significant entropy into the thermal bath that dilutes the dark matter
abundance. We show that this setup can lead to a stable relic population that
reproduces the observed dark matter abundance without requiring weak scale
masses or couplings. The final dark matter abundance is estimated analytically.
We carry out this calculation for arbitrary temperature dependence in the
freeze-out process and identify the viable dark matter mass and cross section
ranges that explain the observed dark matter abundance. This setup can be used
to open parameter space for both heavy (above the unitarity bound) or light
(sub-GeV) dark matter candidates. We point out that the best strategy for
probing most parts of our parameter space is to look for signatures of an early
matter-dominant epoch.
|
[
{
"created": "Mon, 22 Nov 2021 19:00:00 GMT",
"version": "v1"
}
] |
2022-07-27
|
[
[
"Asadi",
"Pouya",
""
],
[
"Slatyer",
"Tracy R.",
""
],
[
"Smirnov",
"Juri",
""
]
] |
We study general freeze-out scenarios where an arbitrary number of initial and final dark matter particles participate in the number-changing freeze-out interaction. We consider a simple sector with two particle species undergoing such a thermal freeze-out; one of the relics is stable and gives rise to the dark matter today, while the other one decays to the Standard Model, injecting significant entropy into the thermal bath that dilutes the dark matter abundance. We show that this setup can lead to a stable relic population that reproduces the observed dark matter abundance without requiring weak scale masses or couplings. The final dark matter abundance is estimated analytically. We carry out this calculation for arbitrary temperature dependence in the freeze-out process and identify the viable dark matter mass and cross section ranges that explain the observed dark matter abundance. This setup can be used to open parameter space for both heavy (above the unitarity bound) or light (sub-GeV) dark matter candidates. We point out that the best strategy for probing most parts of our parameter space is to look for signatures of an early matter-dominant epoch.
|
2101.10683
|
Rafiqul Rahaman
|
Partha Konar, Biswarup Mukhopadhyaya, Rafiqul Rahaman and Ritesh K.
Singh
|
Probing non-standard $b\bar{b}h$ interaction at the LHC at $\sqrt{s}=13$
TeV
|
13 pages, 5 figures, 3 tables
| null |
10.1016/j.physletb.2021.136358
| null |
hep-ph hep-ex
|
http://creativecommons.org/licenses/by/4.0/
|
In the detailed probe of Higgs boson properties at the Large Hadron Collider,
and in looking for new physics signatures in the electroweak symmetry breaking
sector, the bottom quark Yukawa coupling has a crucial role. We investigate
possible departure from the standard model value of $b\bar{b}h$ coupling,
phenomenologically expressed in terms of a modification factor $\alpha_b$, in
$b\bar{b}$-associated production of the $125$-GeV scalar at the high-luminosity
LHC. In a next-to-leading order estimate, we make use of a gradient boosting
algorithm to improve in statistical significance upon a cut-based analysis. It
is found possible to probe down to $\alpha_b = 3$ with more than $5~\sigma$
significance, with ${\cal L} = 3000$ fb$^{-1}$ and $\sqrt{s}$ = 13 TeV, while
the achievable limit at $95\%$ C.L. is $\pm 1.95$.
|
[
{
"created": "Tue, 26 Jan 2021 10:15:11 GMT",
"version": "v1"
}
] |
2021-05-19
|
[
[
"Konar",
"Partha",
""
],
[
"Mukhopadhyaya",
"Biswarup",
""
],
[
"Rahaman",
"Rafiqul",
""
],
[
"Singh",
"Ritesh K.",
""
]
] |
In the detailed probe of Higgs boson properties at the Large Hadron Collider, and in looking for new physics signatures in the electroweak symmetry breaking sector, the bottom quark Yukawa coupling has a crucial role. We investigate possible departure from the standard model value of $b\bar{b}h$ coupling, phenomenologically expressed in terms of a modification factor $\alpha_b$, in $b\bar{b}$-associated production of the $125$-GeV scalar at the high-luminosity LHC. In a next-to-leading order estimate, we make use of a gradient boosting algorithm to improve in statistical significance upon a cut-based analysis. It is found possible to probe down to $\alpha_b = 3$ with more than $5~\sigma$ significance, with ${\cal L} = 3000$ fb$^{-1}$ and $\sqrt{s}$ = 13 TeV, while the achievable limit at $95\%$ C.L. is $\pm 1.95$.
|
1901.03518
|
Zhan-Wei Liu
|
Dan Guo, Cheng-Qun Pang, Zhan-Wei Liu, Xiang Liu
|
Study of Unflavored Light Mesons with $J^{PC}=2^{--}$
|
10 pages, 11 figures; more discussions and some new references are
added
|
Phys. Rev. D 99, 056001 (2019)
|
10.1103/PhysRevD.99.056001
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The unflavored light meson families, namely $\omega_2$, $\rho_2$, and
$\phi_2$, are studied systematically by investigating the spectrum and the
two-body strong decays allowed by Okubo-Zweig-Iizuka rule. Including the four
experimentally observed states and other predicted states, phenomenological
analysis of the partial decay widths can verify the corresponding assignments
of these states into the families. Moreover, we provide typical branching
ratios of the dominant decay channels, especially for missing ground states,
which is helpful to search for or confirm them and explore more properties of
these families at experiment.
|
[
{
"created": "Fri, 11 Jan 2019 09:14:29 GMT",
"version": "v1"
},
{
"created": "Mon, 18 Feb 2019 15:33:08 GMT",
"version": "v2"
},
{
"created": "Wed, 6 Mar 2019 15:30:19 GMT",
"version": "v3"
}
] |
2019-03-07
|
[
[
"Guo",
"Dan",
""
],
[
"Pang",
"Cheng-Qun",
""
],
[
"Liu",
"Zhan-Wei",
""
],
[
"Liu",
"Xiang",
""
]
] |
The unflavored light meson families, namely $\omega_2$, $\rho_2$, and $\phi_2$, are studied systematically by investigating the spectrum and the two-body strong decays allowed by Okubo-Zweig-Iizuka rule. Including the four experimentally observed states and other predicted states, phenomenological analysis of the partial decay widths can verify the corresponding assignments of these states into the families. Moreover, we provide typical branching ratios of the dominant decay channels, especially for missing ground states, which is helpful to search for or confirm them and explore more properties of these families at experiment.
|
1402.3536
|
Robert Thorne S
|
R.S. Thorne
|
The effect on PDFs and $\alpha_S(M_Z^2)$ due to changes in flavour
scheme and higher twist contributions
|
23 pages, 19 figures. Final version. Sioke slightly extended
discussion
|
Eur. Phys. J. C (2014) 74: 2958
|
10.1140/epjc/s10052-014-2958-4
|
LCTS/2012-25
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
I consider the effect on MSTW partons distribution functions (PDFs) due to
changes in the choices of theoretical procedure used in the fit. I first
consider using the 3-flavour fixed flavour number scheme instead of the
standard general mass variable flavour number scheme used in the MSTW analysis.
This results in the light quarks increasing at all relatively small $x$ values,
the gluon distribution becoming smaller at high values of $x$ and larger at
small $x$, the preferred value of the coupling constant $\alpha_S(M_Z^2)$
falling, particularly at NNLO, and the fit quality deteriorates. I also
consider lowering the kinematic cut on $W^2$ for DIS data and simultaneously
introducing higher twist terms which are fit to data. This results in much
smaller effects on both PDFs and $\alpha_S(M_Z^2)$ than the scheme change,
except for quarks at very high $x$. I show that the structure function one
obtains from a fixed input set of PDFs using the fixed flavour scheme and
variable flavour scheme differ significantly for $x \sim 0.01$ at high $Q^2$,
and that this is due to the fact that in the fixed flavour scheme there is a
slow convergence of large logarithmic terms of the form
$(\alpha_S\ln(Q^2/m_c^2))^n$ relevant for this regime. I conclude that some of
the most significant differences in PDF sets are largely due to the choice of
flavour scheme used.
|
[
{
"created": "Fri, 14 Feb 2014 17:29:43 GMT",
"version": "v1"
},
{
"created": "Tue, 5 Aug 2014 14:12:26 GMT",
"version": "v2"
}
] |
2014-08-06
|
[
[
"Thorne",
"R. S.",
""
]
] |
I consider the effect on MSTW partons distribution functions (PDFs) due to changes in the choices of theoretical procedure used in the fit. I first consider using the 3-flavour fixed flavour number scheme instead of the standard general mass variable flavour number scheme used in the MSTW analysis. This results in the light quarks increasing at all relatively small $x$ values, the gluon distribution becoming smaller at high values of $x$ and larger at small $x$, the preferred value of the coupling constant $\alpha_S(M_Z^2)$ falling, particularly at NNLO, and the fit quality deteriorates. I also consider lowering the kinematic cut on $W^2$ for DIS data and simultaneously introducing higher twist terms which are fit to data. This results in much smaller effects on both PDFs and $\alpha_S(M_Z^2)$ than the scheme change, except for quarks at very high $x$. I show that the structure function one obtains from a fixed input set of PDFs using the fixed flavour scheme and variable flavour scheme differ significantly for $x \sim 0.01$ at high $Q^2$, and that this is due to the fact that in the fixed flavour scheme there is a slow convergence of large logarithmic terms of the form $(\alpha_S\ln(Q^2/m_c^2))^n$ relevant for this regime. I conclude that some of the most significant differences in PDF sets are largely due to the choice of flavour scheme used.
|
1107.1215
|
Adam Bzdak
|
A. Bialas, A. Bzdak, K. Zalewski
|
Hidden asymmetry and long range rapidity correlations
|
9 pages, new section 5 with comments, to appear in Phys. Lett. B
| null |
10.1016/j.physletb.2012.03.008
|
RBRC: 910
|
hep-ph nucl-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Interpretation of long-range rapidity correlations in terms of the
fluctuating rapidity density distribution of the system created in high-energy
collisions is proposed. When applied to recent data of the STAR coll., it shows
a substantial asymmetric component in the shape of this system in central Au-Au
collisions, implying that boost invariance is violated on the event-by-event
basis even at central rapidity. This effect may seriously influence the
hydrodynamic expansion of the system.
|
[
{
"created": "Wed, 6 Jul 2011 18:31:03 GMT",
"version": "v1"
},
{
"created": "Thu, 8 Mar 2012 21:44:24 GMT",
"version": "v2"
}
] |
2015-05-28
|
[
[
"Bialas",
"A.",
""
],
[
"Bzdak",
"A.",
""
],
[
"Zalewski",
"K.",
""
]
] |
Interpretation of long-range rapidity correlations in terms of the fluctuating rapidity density distribution of the system created in high-energy collisions is proposed. When applied to recent data of the STAR coll., it shows a substantial asymmetric component in the shape of this system in central Au-Au collisions, implying that boost invariance is violated on the event-by-event basis even at central rapidity. This effect may seriously influence the hydrodynamic expansion of the system.
|
hep-ph/9406308
|
Dave Seckel
|
K.S. Babu, S.M. Barr and D. Seckel
|
Axion Dissipation Through the Mixing of Goldstone Bosons
|
20 pages, Latex, (3 uuencoded compressed tarred postscript figures
attached)
|
Phys.Lett.B336:213-220,1994
|
10.1016/0370-2693(94)90241-0
|
Bartol Preprint, BA-93-16
|
hep-ph astro-ph
| null |
By coupling axions strongly to a hidden sector, the energy density in
coherent axions may be converted to radiative degrees of freedom, alleviating
the ``axion energy crisis''. The strong coupling is achieved by mixing the
axion and some other Goldstone boson through their kinetic energy terms, in a
manner reminiscent of paraphoton models. Even with the strong coupling it
proves difficult to relax the axion energy density through particle absorption,
due to the derivative nature of Goldstone boson couplings and the effect of
back reactions on the evolution of the axion number density. However, the
distribution of other particle species in the hidden sector will be driven from
equilibrium by the axion field oscillations. Restoration of thermal equilibrium
results in energy being transferred from the axions to massless particles,
where it can redshift harmlessly without causing any cosmological problems.
|
[
{
"created": "Tue, 14 Jun 1994 17:47:01 GMT",
"version": "v1"
},
{
"created": "Wed, 15 Jun 1994 13:10:06 GMT",
"version": "v2"
}
] |
2011-05-12
|
[
[
"Babu",
"K. S.",
""
],
[
"Barr",
"S. M.",
""
],
[
"Seckel",
"D.",
""
]
] |
By coupling axions strongly to a hidden sector, the energy density in coherent axions may be converted to radiative degrees of freedom, alleviating the ``axion energy crisis''. The strong coupling is achieved by mixing the axion and some other Goldstone boson through their kinetic energy terms, in a manner reminiscent of paraphoton models. Even with the strong coupling it proves difficult to relax the axion energy density through particle absorption, due to the derivative nature of Goldstone boson couplings and the effect of back reactions on the evolution of the axion number density. However, the distribution of other particle species in the hidden sector will be driven from equilibrium by the axion field oscillations. Restoration of thermal equilibrium results in energy being transferred from the axions to massless particles, where it can redshift harmlessly without causing any cosmological problems.
|
hep-ph/0307049
|
Wim de Boer
|
Wim de Boer, Christian Sander
|
Global Electroweak Fits and Gauge Coupling Unification
|
18 pages, 13 figures
|
Phys.Lett. B585 (2004) 276-286
|
10.1016/j.physletb.2004.01.083
| null |
hep-ph
| null |
The purpose of this paper is threefold: a) Check if the rather poor Standard
Model (SM) fit to all electroweak data can be improved in its minimal
supersymmetric extension (MSSM); b) Check what constraints present electroweak
data has on the parameter space of the supergravity inspired Constrained MSSM
(CMSSM); c) Check if with the present high precision of the gauge coupling
constants exact gauge coupling unification is still possible. The value of
tan\beta in the CMSSM is constrained to be above 6.5, while the value of the
gaugino masses at the GUT scale has to be above 220 GeV, which corresponds to a
lower limit on the lightest neutralino (chargino) of ca. 95 (175) GeV. It is
shown that the larger values of \alpha_s from R_l and \sinw from A_FB are
consistent with perfect gauge unification. The low \alpha_s value from the
hadronic cross section is correlated with the fact that the number of neutrino
flavours is 2\sigma below the known value of 3 in the SM, which is shown to
correspond to a 3sigma deviation in the hadronic cross section. Lowering
sigma_{had} by 3sigma brings alpha_s up to 0.12 and N_nu up to 3.
|
[
{
"created": "Thu, 3 Jul 2003 17:50:51 GMT",
"version": "v1"
}
] |
2009-11-10
|
[
[
"de Boer",
"Wim",
""
],
[
"Sander",
"Christian",
""
]
] |
The purpose of this paper is threefold: a) Check if the rather poor Standard Model (SM) fit to all electroweak data can be improved in its minimal supersymmetric extension (MSSM); b) Check what constraints present electroweak data has on the parameter space of the supergravity inspired Constrained MSSM (CMSSM); c) Check if with the present high precision of the gauge coupling constants exact gauge coupling unification is still possible. The value of tan\beta in the CMSSM is constrained to be above 6.5, while the value of the gaugino masses at the GUT scale has to be above 220 GeV, which corresponds to a lower limit on the lightest neutralino (chargino) of ca. 95 (175) GeV. It is shown that the larger values of \alpha_s from R_l and \sinw from A_FB are consistent with perfect gauge unification. The low \alpha_s value from the hadronic cross section is correlated with the fact that the number of neutrino flavours is 2\sigma below the known value of 3 in the SM, which is shown to correspond to a 3sigma deviation in the hadronic cross section. Lowering sigma_{had} by 3sigma brings alpha_s up to 0.12 and N_nu up to 3.
|
2203.00244
|
Yuping Guo
|
Y. P. Guo and C. Z. Yuan
|
Impact of the interference between the resonance and continuum
amplitudes on vector quarkonia decay branching fraction measurements
| null |
Phys. Rev. D 105, 114001 (2022)
|
10.1103/PhysRevD.105.114001
| null |
hep-ph hep-ex
|
http://creativecommons.org/licenses/by/4.0/
|
The measurement of the branching fraction of a heavy quarkonium decaying into
light hadronic final state at $e^+e^-$ colliders is revisited. In $e^+e^-$
annihilation experiments, background contributions from the continuum amplitude
and its interference with the resonance amplitude are irreducible. These
effects become more and more significant as the precision of experimental
measurements improves. While the former can be easily subtracted with data
taken off the resonance peak, the latter depends on the relative size and phase
between the resonance and continuum amplitudes. Two ratios are defined to
estimate the size of these effects, $r_{R}^{f}$ for the ratio of the
contribution of the interference term to the resonance term and $r_{c}^{f}$ for
that to the continuum term. We find that $r_{R}^{f}$ could be as large as a few
percent for narrow resonances, and both $r_{R}^{f}$ and $r_{c}^{f}$ could be
large for broad resonances. This indicates that the interference effect is
crucial for the measurements of the branching fractions aiming at the percent
level or better precision and needs to be measured or estimated properly.
|
[
{
"created": "Tue, 1 Mar 2022 05:50:09 GMT",
"version": "v1"
},
{
"created": "Fri, 17 Jun 2022 03:13:30 GMT",
"version": "v2"
}
] |
2022-06-20
|
[
[
"Guo",
"Y. P.",
""
],
[
"Yuan",
"C. Z.",
""
]
] |
The measurement of the branching fraction of a heavy quarkonium decaying into light hadronic final state at $e^+e^-$ colliders is revisited. In $e^+e^-$ annihilation experiments, background contributions from the continuum amplitude and its interference with the resonance amplitude are irreducible. These effects become more and more significant as the precision of experimental measurements improves. While the former can be easily subtracted with data taken off the resonance peak, the latter depends on the relative size and phase between the resonance and continuum amplitudes. Two ratios are defined to estimate the size of these effects, $r_{R}^{f}$ for the ratio of the contribution of the interference term to the resonance term and $r_{c}^{f}$ for that to the continuum term. We find that $r_{R}^{f}$ could be as large as a few percent for narrow resonances, and both $r_{R}^{f}$ and $r_{c}^{f}$ could be large for broad resonances. This indicates that the interference effect is crucial for the measurements of the branching fractions aiming at the percent level or better precision and needs to be measured or estimated properly.
|
1901.09095
|
Christopher Lee
|
Christopher Lee, Prashant Shrivastava and Varun Vaidya
|
Predictions for energy correlators probing substructure of groomed heavy
quark jets
|
50 pages, 16 figures. v2: improved discussions of phase space
boundaries and transition points in EFT vs. fixed-order computations,
numerous other minor clarifications and corrections. v3: minor clarifications
and corrections, version published in JHEP
| null |
10.1007/JHEP09(2019)045
|
LA-UR-18-24853
|
hep-ph nucl-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We develop an effective field theory (EFT) framework to perform an analytic
calculation for energy correlator observables computed on groomed heavy-quark
jets. A soft-drop grooming algorithm is applied to a jet initiated by a massive
quark to minimize soft contamination effects such as pile-up and multi-parton
interactions. We specifically consider the two-particle energy correlator as an
initial application of this EFT framework to compute heavy quark jet
substructure. We find that there are different regimes for the event shapes,
depending on the size of the measured correlator observable, that require the
use of different EFT formulations, in which the quark mass and grooming
parameters may be relevant or not. We use the EFT to resum large logarithms in
the energy correlator observable in terms of the momentum of a reconstructed
heavy hadron to NLL$'$ accuracy and subsequently match it to a full QCD
$\mathcal{O}(\alpha_s)$ cross section, which we also compute. We compare our
predictions to simulations in PYTHIA for $e^+e^-$ collisions. We find a good
agreement with partonic simulations, as well as hadronic ones with an
appropriate shape function used to describe nonperturbative effects and the
heavy quark hadron decay turned off. We also predict the scaling behavior for
the leading nonperturbative power correction due to hadronization.
Consequently, we can give a prediction for the energy correlator distribution
at the level of the reconstructed heavy hadron. This work provides a general
framework for the analysis of heavy quark jet substructure observables.
|
[
{
"created": "Fri, 25 Jan 2019 21:53:32 GMT",
"version": "v1"
},
{
"created": "Mon, 13 May 2019 20:52:38 GMT",
"version": "v2"
},
{
"created": "Thu, 15 Aug 2019 17:37:06 GMT",
"version": "v3"
}
] |
2019-10-02
|
[
[
"Lee",
"Christopher",
""
],
[
"Shrivastava",
"Prashant",
""
],
[
"Vaidya",
"Varun",
""
]
] |
We develop an effective field theory (EFT) framework to perform an analytic calculation for energy correlator observables computed on groomed heavy-quark jets. A soft-drop grooming algorithm is applied to a jet initiated by a massive quark to minimize soft contamination effects such as pile-up and multi-parton interactions. We specifically consider the two-particle energy correlator as an initial application of this EFT framework to compute heavy quark jet substructure. We find that there are different regimes for the event shapes, depending on the size of the measured correlator observable, that require the use of different EFT formulations, in which the quark mass and grooming parameters may be relevant or not. We use the EFT to resum large logarithms in the energy correlator observable in terms of the momentum of a reconstructed heavy hadron to NLL$'$ accuracy and subsequently match it to a full QCD $\mathcal{O}(\alpha_s)$ cross section, which we also compute. We compare our predictions to simulations in PYTHIA for $e^+e^-$ collisions. We find a good agreement with partonic simulations, as well as hadronic ones with an appropriate shape function used to describe nonperturbative effects and the heavy quark hadron decay turned off. We also predict the scaling behavior for the leading nonperturbative power correction due to hadronization. Consequently, we can give a prediction for the energy correlator distribution at the level of the reconstructed heavy hadron. This work provides a general framework for the analysis of heavy quark jet substructure observables.
|
hep-ph/0011230
|
Jiunn-Wei Chen
|
Jiunn-Wei Chen and Xiangdong Ji
|
Measuring the P-odd Pion-Nucleon Coupling h_{\pi NN}^{(1)} in \pi^+
Photoproton Production Near the Threshold
|
4 pages, 3 figures. More data points in fig. 1 and note added in
proof added
|
Phys.Rev.Lett. 86 (2001) 4239-4242
|
10.1103/PhysRevLett.86.4239
|
DOE/ER/40762-218, UMD-PP-01-018
|
hep-ph nucl-ex nucl-th
| null |
We show that polarized gamma p -> \pi^+ n in the threshold region is an
excellent candidate for measuring the leading parity-violating pion-nucleon
coupling h_{\pi NN}^{(1)} to an uncertainty of 20% if it has a natural size
from dimensional analysis. The conclusion is based on a large unpolarized cross
section, a new low-energy theorem for the photon polarization asymmetry at the
threshold A_\gamma|_{th} = \sqrt{2} f_\pi (\mu_p-\mu_n) h_{\pi NN}^{(1)}/g_A
m_N \sim h_{\pi NN}^{(1)}/2, and its strong dominance at forward and backward
angles in the threshold region.
|
[
{
"created": "Sat, 18 Nov 2000 17:48:58 GMT",
"version": "v1"
},
{
"created": "Tue, 13 Feb 2001 20:08:54 GMT",
"version": "v2"
}
] |
2009-10-31
|
[
[
"Chen",
"Jiunn-Wei",
""
],
[
"Ji",
"Xiangdong",
""
]
] |
We show that polarized gamma p -> \pi^+ n in the threshold region is an excellent candidate for measuring the leading parity-violating pion-nucleon coupling h_{\pi NN}^{(1)} to an uncertainty of 20% if it has a natural size from dimensional analysis. The conclusion is based on a large unpolarized cross section, a new low-energy theorem for the photon polarization asymmetry at the threshold A_\gamma|_{th} = \sqrt{2} f_\pi (\mu_p-\mu_n) h_{\pi NN}^{(1)}/g_A m_N \sim h_{\pi NN}^{(1)}/2, and its strong dominance at forward and backward angles in the threshold region.
|
hep-ph/0008335
|
Abada
|
A. Abada, K. Bouakaz and N. Daira-Aifa
|
Damping of very soft moving quarks in high-temperature QCD
|
24 pages, REVTeX
|
Eur.Phys.J.C18:765-777,2001
|
10.1007/s100520100554
| null |
hep-ph
| null |
We determine the analytic expression of the damping rates for very soft
moving quarks in an expansion to second order in powers of their momentum in
the context of QCD at high temperature. The calculation is performed using the
hard-thermal-loop-summed perturbation scheme. We describe the range of validity
of the expansion and make a comparison with other calculations, particularly
those using a magnetic mass as a shield from infrared sensitivity. We discuss
the possible occurrence of infrared divergences in our results and argue that
they are due to magnetic sensitivity.
|
[
{
"created": "Thu, 31 Aug 2000 17:53:40 GMT",
"version": "v1"
}
] |
2009-01-07
|
[
[
"Abada",
"A.",
""
],
[
"Bouakaz",
"K.",
""
],
[
"Daira-Aifa",
"N.",
""
]
] |
We determine the analytic expression of the damping rates for very soft moving quarks in an expansion to second order in powers of their momentum in the context of QCD at high temperature. The calculation is performed using the hard-thermal-loop-summed perturbation scheme. We describe the range of validity of the expansion and make a comparison with other calculations, particularly those using a magnetic mass as a shield from infrared sensitivity. We discuss the possible occurrence of infrared divergences in our results and argue that they are due to magnetic sensitivity.
|
1704.07835
|
Artur Ankowski
|
Artur M. Ankowski
|
Nuclear effects are relevant to the calorimetric reconstruction of
neutrino energy
|
5 pages, 2 figures
| null | null | null |
hep-ph hep-ex nucl-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
As the calorimetric method of neutrino-energy reconstruction is generally
considered to be largely insensitive to nuclear effects, its application seems
to be an effective way for reducing systematic uncertainties in oscillation
experiments. To verify the validity of this opinion, we quantitatively study
the sensitivity of the calorimetric energy reconstruction to the effect of
final-state interactions in an ideal detector and in a realistic scenario. We
find that when particles escaping detection carry away a non-negligible
fraction of neutrino energy, the calorimetric reconstruction method becomes
sensitive to nuclear effects which, in turn, affects the outcome of the
oscillation analysis. These findings suggest that the best strategy for
reduction of systematic uncertainties in future neutrino-oscillation
studies---such as the Deep Underground Neutrino Experiment---is to increase
their sensitivity to particles of low energy. The ambitious precision goals
appear also to require an extensive development of theoretical models capable
of providing an accurate predictions for exclusive cross sections of
well-controlled uncertainties.
|
[
{
"created": "Tue, 25 Apr 2017 18:00:12 GMT",
"version": "v1"
}
] |
2017-04-27
|
[
[
"Ankowski",
"Artur M.",
""
]
] |
As the calorimetric method of neutrino-energy reconstruction is generally considered to be largely insensitive to nuclear effects, its application seems to be an effective way for reducing systematic uncertainties in oscillation experiments. To verify the validity of this opinion, we quantitatively study the sensitivity of the calorimetric energy reconstruction to the effect of final-state interactions in an ideal detector and in a realistic scenario. We find that when particles escaping detection carry away a non-negligible fraction of neutrino energy, the calorimetric reconstruction method becomes sensitive to nuclear effects which, in turn, affects the outcome of the oscillation analysis. These findings suggest that the best strategy for reduction of systematic uncertainties in future neutrino-oscillation studies---such as the Deep Underground Neutrino Experiment---is to increase their sensitivity to particles of low energy. The ambitious precision goals appear also to require an extensive development of theoretical models capable of providing an accurate predictions for exclusive cross sections of well-controlled uncertainties.
|
2303.15624
|
Mao Zeng
|
Mao Zeng
|
Feynman Integrals from Positivity Constraints
|
43 pages, 14 figures
|
JHEP 09 (2023) 042
|
10.1007/JHEP09(2023)042
| null |
hep-ph hep-th
|
http://creativecommons.org/licenses/by/4.0/
|
We explore inequality constraints as a new tool for numerically evaluating
Feynman integrals. A convergent Feynman integral is non-negative if the
integrand is non-negative in either loop momentum space or Feynman parameter
space. Applying various identities, all such integrals can be reduced to linear
sums of a small set of master integrals, leading to infinitely many linear
constraints on the values of the master integrals. The constraints can be
solved as a semidefinite programming problem in mathematical optimization,
producing rigorous two-sided bounds for the integrals which are observed to
converge rapidly as more constraints are included, enabling high-precision
determination of the integrals. Positivity constraints can also be formulated
for the $\epsilon$ expansion terms in dimensional regularization and reveal
hidden consistency relations between terms at different orders in $\epsilon$.
We introduce the main methods using one-loop bubble integrals, then present a
nontrivial example of three-loop banana integrals with unequal masses, where 11
top-level master integrals are evaluated to high precision.
|
[
{
"created": "Mon, 27 Mar 2023 22:41:06 GMT",
"version": "v1"
},
{
"created": "Tue, 3 Oct 2023 19:42:44 GMT",
"version": "v2"
}
] |
2023-10-05
|
[
[
"Zeng",
"Mao",
""
]
] |
We explore inequality constraints as a new tool for numerically evaluating Feynman integrals. A convergent Feynman integral is non-negative if the integrand is non-negative in either loop momentum space or Feynman parameter space. Applying various identities, all such integrals can be reduced to linear sums of a small set of master integrals, leading to infinitely many linear constraints on the values of the master integrals. The constraints can be solved as a semidefinite programming problem in mathematical optimization, producing rigorous two-sided bounds for the integrals which are observed to converge rapidly as more constraints are included, enabling high-precision determination of the integrals. Positivity constraints can also be formulated for the $\epsilon$ expansion terms in dimensional regularization and reveal hidden consistency relations between terms at different orders in $\epsilon$. We introduce the main methods using one-loop bubble integrals, then present a nontrivial example of three-loop banana integrals with unequal masses, where 11 top-level master integrals are evaluated to high precision.
|
hep-ph/9603406
| null |
Somenath Chakrabarty
|
Quark Matter in Strong Magnetic Field
|
31 Pages TEX file, with 9-figures available under request
|
Phys.Rev.D54:1306-1316,1996
|
10.1103/PhysRevD.54.1306
| null |
hep-ph
| null |
The effect of strong magnetic field on the stability and gross properties of
bulk as well as quasi-bulk quark matter has been investigated using the
conventional MIT bag model. Both the Landau diamagnetism and the paramagnetism
of quark matter has been studied. How the quark hadron phase transition is
affected by the presence of strong magnetic field has also been investigated.
The equation of state of strange quark matter changes significantly in strong
magnetic field. It is also shown that the thermal nucleation of quark bubbles
in compact metastable state of neutron matter is completely forbidden in
presence of strong magnetic field.
|
[
{
"created": "Thu, 21 Mar 1996 18:21:00 GMT",
"version": "v1"
}
] |
2011-05-05
|
[
[
"Chakrabarty",
"Somenath",
""
]
] |
The effect of strong magnetic field on the stability and gross properties of bulk as well as quasi-bulk quark matter has been investigated using the conventional MIT bag model. Both the Landau diamagnetism and the paramagnetism of quark matter has been studied. How the quark hadron phase transition is affected by the presence of strong magnetic field has also been investigated. The equation of state of strange quark matter changes significantly in strong magnetic field. It is also shown that the thermal nucleation of quark bubbles in compact metastable state of neutron matter is completely forbidden in presence of strong magnetic field.
|
1202.6295
|
Masato Jimbo
|
M. Jimbo, T. Inoue, T. Jujo, T. Kon, T. Ishikawa, Y. Kurihara, K. Kato
and M. Kuroda
|
Pair-production and Three-body Decay of the Lighter Stop at the ILC in
One-loop Order in the MSSM
|
6 pages, 5 figures (7 eps files), Prepared for the Proceedings of
International Workshop on Future Linear Colliders, LCWS11, 26-30 September
2011, Palacio de Exposiciones y Congresos, Granada, Spain
| null | null |
CUCP-12-1, KEK-CP-265
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We have been developing a program package called GRACE/SUSY-loop which
automatically calculates the MSSM amplitudes in one-loop order. We present
numerical results of calculations for pair-production and three-body decay of
the lighter stop ($\widetilde{t}_1$) at the International Linear Collider (ILC)
using GRACE/SUSY-loop. Since the distributions of missing transverse energy
(MET) depend on mass spectrum of SUSY particles, we consider two scenarios on
three-body decay of $\widetilde{t}_1$. In these scenarios, both QCD and EW
corrections have positive sign for decay widths and cross sections.
|
[
{
"created": "Tue, 28 Feb 2012 17:31:24 GMT",
"version": "v1"
}
] |
2012-02-29
|
[
[
"Jimbo",
"M.",
""
],
[
"Inoue",
"T.",
""
],
[
"Jujo",
"T.",
""
],
[
"Kon",
"T.",
""
],
[
"Ishikawa",
"T.",
""
],
[
"Kurihara",
"Y.",
""
],
[
"Kato",
"K.",
""
],
[
"Kuroda",
"M.",
""
]
] |
We have been developing a program package called GRACE/SUSY-loop which automatically calculates the MSSM amplitudes in one-loop order. We present numerical results of calculations for pair-production and three-body decay of the lighter stop ($\widetilde{t}_1$) at the International Linear Collider (ILC) using GRACE/SUSY-loop. Since the distributions of missing transverse energy (MET) depend on mass spectrum of SUSY particles, we consider two scenarios on three-body decay of $\widetilde{t}_1$. In these scenarios, both QCD and EW corrections have positive sign for decay widths and cross sections.
|
1210.7712
|
Xumeu Planells
|
Alexander A. Andrianov, Domenec Espriu and Xumeu Planells
|
An effective QCD Lagrangian in the presence of an axial chemical
potential
|
13 pages, 9 figures
| null |
10.1140/epjc/s10052-013-2294-0
|
ICCUB-12-363; UB-ECM-PF-80/12
|
hep-ph nucl-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We consider the low energy realization of QCD in terms of mesons when an
axial chemical potential is present; a situation that may be relevant in heavy
ion collisions. We shall demonstrate that the presence of an axial charge has
profound consequences on meson physics. The most notorious effect is the
appearance of an explicit source of parity breaking. The eigenstates of strong
interactions do not have a definite parity and interactions that would
otherwise be forbidden compete with the familiar ones. In this work we focus on
scalars and pseudoscalars that are described by a generalized linear sigma
model. We comment briefly on the screening role of axial vectors in formation
of effective axial charge and on the possible experimental relevance of our
results, whose consequences may have been already seen at RHIC.
|
[
{
"created": "Mon, 29 Oct 2012 16:19:49 GMT",
"version": "v1"
}
] |
2015-06-11
|
[
[
"Andrianov",
"Alexander A.",
""
],
[
"Espriu",
"Domenec",
""
],
[
"Planells",
"Xumeu",
""
]
] |
We consider the low energy realization of QCD in terms of mesons when an axial chemical potential is present; a situation that may be relevant in heavy ion collisions. We shall demonstrate that the presence of an axial charge has profound consequences on meson physics. The most notorious effect is the appearance of an explicit source of parity breaking. The eigenstates of strong interactions do not have a definite parity and interactions that would otherwise be forbidden compete with the familiar ones. In this work we focus on scalars and pseudoscalars that are described by a generalized linear sigma model. We comment briefly on the screening role of axial vectors in formation of effective axial charge and on the possible experimental relevance of our results, whose consequences may have been already seen at RHIC.
|
1803.03038
|
Rupak Dutta
|
Rupak Dutta and Rajeev N
|
Signature of Lepton flavor universality violation in $B_s \to
D_s\tau\nu$ semileptonic decays
|
14 pages, 9 figures
|
Phys. Rev. D 97, 095045 (2018)
|
10.1103/PhysRevD.97.095045
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Deviation from the standard model prediction is observed in many semileptonic
$B$ decays mediated via $b \to c$ charged current interactions. In particular,
current experimental measurements of the ratio of branching ratio $R_D$ and
$R_{D^{\ast}}$ in $B \rightarrow D^{(*)}l \nu$ decays disagree with standard
model expectations at the level of about $4.1\sigma$. Moreover, recent
measurement of the ratio of branching ratio $R_{J/\Psi}$ by LHCb, where
$R_{J/\Psi} = \mathcal B(B_c \to J/\Psi\,\tau\nu)/\mathcal B(B_c \to
J/\Psi\,\mu\nu)$, is more than $2\sigma$ away from the standard model
prediction. In this context, we consider an effective Lagrangian in the
presence of vector and scalar new physics couplings to study the implications
of $R_D$ and $R_{D^{\ast}}$ anomalies in $B_s \to D_s\,\tau\nu$ decays. We give
prediction of several observables such as branching ratio, ratio of branching
ratio, forward backward asymmetry parameter, $\tau$ polarization fraction, and
the convexity parameter for the $B_s \to D_s\,\tau\nu$ decays within the
standard model and within various new physics scenarios.
|
[
{
"created": "Thu, 8 Mar 2018 10:59:02 GMT",
"version": "v1"
}
] |
2018-06-06
|
[
[
"Dutta",
"Rupak",
""
],
[
"N",
"Rajeev",
""
]
] |
Deviation from the standard model prediction is observed in many semileptonic $B$ decays mediated via $b \to c$ charged current interactions. In particular, current experimental measurements of the ratio of branching ratio $R_D$ and $R_{D^{\ast}}$ in $B \rightarrow D^{(*)}l \nu$ decays disagree with standard model expectations at the level of about $4.1\sigma$. Moreover, recent measurement of the ratio of branching ratio $R_{J/\Psi}$ by LHCb, where $R_{J/\Psi} = \mathcal B(B_c \to J/\Psi\,\tau\nu)/\mathcal B(B_c \to J/\Psi\,\mu\nu)$, is more than $2\sigma$ away from the standard model prediction. In this context, we consider an effective Lagrangian in the presence of vector and scalar new physics couplings to study the implications of $R_D$ and $R_{D^{\ast}}$ anomalies in $B_s \to D_s\,\tau\nu$ decays. We give prediction of several observables such as branching ratio, ratio of branching ratio, forward backward asymmetry parameter, $\tau$ polarization fraction, and the convexity parameter for the $B_s \to D_s\,\tau\nu$ decays within the standard model and within various new physics scenarios.
|
0911.1986
|
Are R. Raklev
|
A.R. Raklev, M.J. White
|
Constraining the MSSM with Dark Matter indirect detection data
|
5 pages, 3 figures
| null | null |
CAVENDISH-HEP-2009-23
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Recently, a claim of possible evidence for Dark Matter in data from the Fermi
LAT experiment was made by Goodenough and Hooper [8]. We test the Dark Matter
properties consistent with their claim in terms of the MSSM by a 24-dimensional
parameter scan using nested sampling, excluding all but a very small region of
the MSSM. Although this claim is very preliminary, and not made by the Fermi
LAT experiment, our scan shows a possible approach for the analysis of future
firm evidence from an indirect detection experiment, and its potential for
heavily constraining models.
|
[
{
"created": "Tue, 10 Nov 2009 20:51:20 GMT",
"version": "v1"
}
] |
2009-11-11
|
[
[
"Raklev",
"A. R.",
""
],
[
"White",
"M. J.",
""
]
] |
Recently, a claim of possible evidence for Dark Matter in data from the Fermi LAT experiment was made by Goodenough and Hooper [8]. We test the Dark Matter properties consistent with their claim in terms of the MSSM by a 24-dimensional parameter scan using nested sampling, excluding all but a very small region of the MSSM. Although this claim is very preliminary, and not made by the Fermi LAT experiment, our scan shows a possible approach for the analysis of future firm evidence from an indirect detection experiment, and its potential for heavily constraining models.
|
2309.13112
|
Valentina Danieli
|
Valentina Danieli, Takeshi Kobayashi, Nicola Bartolo, Sabino Matarrese
and Matteo Viel
|
Anharmonic Effects on the Squeezing of Axion Perturbations
|
22 pages + appendices, 10 figures
|
JCAP04(2024)058
|
10.1088/1475-7516/2024/04/058
| null |
hep-ph astro-ph.CO gr-qc hep-th quant-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
It is assumed in standard cosmology that the Universe underwent a period of
inflation in its earliest phase, providing the seeds for structure formation
through vacuum fluctuations of the inflaton scalar field. These fluctuations
get stretched by the quasi-exponential expansion of the Universe and become
squeezed. The aim of this paper is to deepen the understanding of the squeezing
process, considering the effect of self-interactions. Axion-like particles can
provide a useful setup to study this effect. Specifically we focus on the
consequences that a non-trivial evolution of the background axion field has on
the squeezing of the perturbations. We follow the evolution of the axion's
fluctuation modes from the horizon exit during inflation to the
radiation-dominated epoch. We compute Bogoliubov coefficients and squeezing
parameters, which are linked to the axion particle number and isocurvature
perturbation. We find that the quantum mechanical particle production and the
squeezing of the perturbations are enhanced, if one accounts for anharmonic
effects, i.e., the effect of higher order terms in the potential. This effect
becomes particularly strong towards the hilltop of the potential.
|
[
{
"created": "Fri, 22 Sep 2023 18:00:04 GMT",
"version": "v1"
},
{
"created": "Thu, 18 Apr 2024 21:45:31 GMT",
"version": "v2"
}
] |
2024-04-22
|
[
[
"Danieli",
"Valentina",
""
],
[
"Kobayashi",
"Takeshi",
""
],
[
"Bartolo",
"Nicola",
""
],
[
"Matarrese",
"Sabino",
""
],
[
"Viel",
"Matteo",
""
]
] |
It is assumed in standard cosmology that the Universe underwent a period of inflation in its earliest phase, providing the seeds for structure formation through vacuum fluctuations of the inflaton scalar field. These fluctuations get stretched by the quasi-exponential expansion of the Universe and become squeezed. The aim of this paper is to deepen the understanding of the squeezing process, considering the effect of self-interactions. Axion-like particles can provide a useful setup to study this effect. Specifically we focus on the consequences that a non-trivial evolution of the background axion field has on the squeezing of the perturbations. We follow the evolution of the axion's fluctuation modes from the horizon exit during inflation to the radiation-dominated epoch. We compute Bogoliubov coefficients and squeezing parameters, which are linked to the axion particle number and isocurvature perturbation. We find that the quantum mechanical particle production and the squeezing of the perturbations are enhanced, if one accounts for anharmonic effects, i.e., the effect of higher order terms in the potential. This effect becomes particularly strong towards the hilltop of the potential.
|
hep-ph/9901389
|
Demir Durmus Ali
|
D. A. Demir
|
Effects of the supersymmetric phases on the neutral Higgs sector
|
24 pp, 8 figs, 2 tables, typos and errors corrected
|
Phys. Rev. D 60, 055006 (1999)
|
10.1103/PhysRevD.60.055006
|
IC/99/1
|
hep-ph
| null |
By using the effective potential approximation and taking into account the
dominant top quark and scalar top quark loops, radiative corrections to MSSM
Higgs potential are computed in the presence of the supersymmetric CP-violating
phases. It is found that, the lightest Higgs scalar remains essentially CP-even
as in the CP-invariant theory whereas the other two scalars are heavy and do
not have definite CP properties. The supersymmetric CP-violating phases are
shown to modify significantly the decay rates of the scalars to fermion pairs.
|
[
{
"created": "Fri, 22 Jan 1999 21:56:05 GMT",
"version": "v1"
},
{
"created": "Tue, 30 Mar 1999 22:43:09 GMT",
"version": "v2"
}
] |
2016-08-25
|
[
[
"Demir",
"D. A.",
""
]
] |
By using the effective potential approximation and taking into account the dominant top quark and scalar top quark loops, radiative corrections to MSSM Higgs potential are computed in the presence of the supersymmetric CP-violating phases. It is found that, the lightest Higgs scalar remains essentially CP-even as in the CP-invariant theory whereas the other two scalars are heavy and do not have definite CP properties. The supersymmetric CP-violating phases are shown to modify significantly the decay rates of the scalars to fermion pairs.
|
2012.12421
|
Jen-Chieh Peng
|
Gordon Baym and Jen-Chieh Peng
|
Evolution of Primordial Neutrino Helicities in Astrophysical Magnetic
Fields and Implications for their Detection
|
7 pages, 1 figure, typos corrected, references added, to be published
in Phys. Rev. Lett
|
Phys. Rev. Lett. 126, 191803 (2021)
|
10.1103/PhysRevLett.126.191803
| null |
hep-ph astro-ph.CO hep-ex nucl-th
|
http://creativecommons.org/licenses/by/4.0/
|
Since decoupling in the early universe in helicity states, primordial
neutrinos propagating in astrophysical magnetic fields precess and undergo
helicity changes. In view of the XENON1T experiment possibly finding a large
magnetic moment of solar neutrinos, we estimate the helicity flipping for relic
neutrinos in both cosmic and galactic magnetic fields. The flipping probability
is sensitive both to the neutrino magnetic moment and the structure of the
magnetic fields, thus potentially a probe of the fields. As we find, even a
magnetic moment well below that suggested by XENON1T could significantly affect
relic neutrino helicities and their detection rate via inverse tritium beta
decay.
|
[
{
"created": "Tue, 22 Dec 2020 23:59:27 GMT",
"version": "v1"
},
{
"created": "Sun, 31 Jan 2021 02:40:15 GMT",
"version": "v2"
},
{
"created": "Mon, 19 Apr 2021 01:28:01 GMT",
"version": "v3"
}
] |
2021-05-19
|
[
[
"Baym",
"Gordon",
""
],
[
"Peng",
"Jen-Chieh",
""
]
] |
Since decoupling in the early universe in helicity states, primordial neutrinos propagating in astrophysical magnetic fields precess and undergo helicity changes. In view of the XENON1T experiment possibly finding a large magnetic moment of solar neutrinos, we estimate the helicity flipping for relic neutrinos in both cosmic and galactic magnetic fields. The flipping probability is sensitive both to the neutrino magnetic moment and the structure of the magnetic fields, thus potentially a probe of the fields. As we find, even a magnetic moment well below that suggested by XENON1T could significantly affect relic neutrino helicities and their detection rate via inverse tritium beta decay.
|
1411.2592
|
Prateek Agrawal
|
Prateek Agrawal, Brian Batell, Patrick J. Fox and Roni Harnik
|
WIMPs at the Galactic Center
|
26 pages, 10 figures, 1 table
| null |
10.1088/1475-7516/2015/05/011
|
FERMILAB-PUB-14-411-T, CERN-PH-TH-2014-219
|
hep-ph astro-ph.CO astro-ph.HE
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Simple models of weakly interacting massive particles (WIMPs) predict dark
matter annihilations into pairs of electroweak gauge bosons, Higgses or tops,
which through their subsequent cascade decays produce a spectrum of gamma rays.
Intriguingly, an excess in gamma rays coming from near the Galactic center has
been consistently observed in Fermi data. A recent analysis by the Fermi
collaboration confirms these earlier results. Taking into account the
systematic uncertainties in the modelling of the gamma ray backgrounds, we show
for the first time that this excess can be well fit by these final states. In
particular, for annihilations to $(WW, ZZ, hh, tt)$, dark matter with mass
between threshold and approximately (165, 190, 280, 310) GeV gives an
acceptable fit. The fit range for $b\bar{b}$ is also enlarged to 35
GeV$\lesssim m_\chi \lesssim$ 165 GeV. These are to be compared to previous
fits that concluded only much lighter dark matter annihilating into $b$,
$\tau$, and light quark final states could describe the excess. We demonstrate
that simple, well-motivated models of WIMP dark matter including a
thermal-relic neutralino of the MSSM, Higgs portal models, as well as other
simplified models can explain the excess.
|
[
{
"created": "Mon, 10 Nov 2014 21:00:03 GMT",
"version": "v1"
}
] |
2015-05-20
|
[
[
"Agrawal",
"Prateek",
""
],
[
"Batell",
"Brian",
""
],
[
"Fox",
"Patrick J.",
""
],
[
"Harnik",
"Roni",
""
]
] |
Simple models of weakly interacting massive particles (WIMPs) predict dark matter annihilations into pairs of electroweak gauge bosons, Higgses or tops, which through their subsequent cascade decays produce a spectrum of gamma rays. Intriguingly, an excess in gamma rays coming from near the Galactic center has been consistently observed in Fermi data. A recent analysis by the Fermi collaboration confirms these earlier results. Taking into account the systematic uncertainties in the modelling of the gamma ray backgrounds, we show for the first time that this excess can be well fit by these final states. In particular, for annihilations to $(WW, ZZ, hh, tt)$, dark matter with mass between threshold and approximately (165, 190, 280, 310) GeV gives an acceptable fit. The fit range for $b\bar{b}$ is also enlarged to 35 GeV$\lesssim m_\chi \lesssim$ 165 GeV. These are to be compared to previous fits that concluded only much lighter dark matter annihilating into $b$, $\tau$, and light quark final states could describe the excess. We demonstrate that simple, well-motivated models of WIMP dark matter including a thermal-relic neutralino of the MSSM, Higgs portal models, as well as other simplified models can explain the excess.
|
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