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|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1111.5705 | Valeriy Nazaruk | Valeriy Nazaruk | Models of $n\bar{n}$ transition in medium | 10 pages, 2 figures. arXiv admin note: substantial text overlap with
arXiv:1101.2310 and arXiv:1003.4360 | null | null | null | hep-ph nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The present state of the $n\bar{n}$ transition problem is briefly outlined.
The models based on the diagram technique for direct reactions, potential
description of $\bar{n}$-medium interaction and field-theoretical approach are
considered. It is shown that for the $n\bar{n}$ transition in medium
field-theoretical approach should be used. The lower limit on the free-space
$n\bar{n}$ oscillation time $\tau_{{\rm min}}$ is found to be: $10^{16}\; {\rm
yr}>\tau_{{\rm min}}>1.2\cdot 10^{9}\; {\rm s}$.
| [
{
"created": "Thu, 24 Nov 2011 09:38:01 GMT",
"version": "v1"
}
] | 2011-11-28 | [
[
"Nazaruk",
"Valeriy",
""
]
] | The present state of the $n\bar{n}$ transition problem is briefly outlined. The models based on the diagram technique for direct reactions, potential description of $\bar{n}$-medium interaction and field-theoretical approach are considered. It is shown that for the $n\bar{n}$ transition in medium field-theoretical approach should be used. The lower limit on the free-space $n\bar{n}$ oscillation time $\tau_{{\rm min}}$ is found to be: $10^{16}\; {\rm yr}>\tau_{{\rm min}}>1.2\cdot 10^{9}\; {\rm s}$. |
1901.01936 | Mikhail Voloshin | M.B. Voloshin | Strange hadrocharmonium | 7 pages, 2 figures | null | 10.1016/j.physletb.2019.135022 | FTPI-MINN-19/02, UMN-TH-3811/19 | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | It has been recently suggested that the charged charmoniumlike resonances
$Z_c(4100)$ and $Z_c(4200)$ are two states of hadrocharmonium, related by the
charm quark spin symmetry in the same way as the lowest charmonium states
$\eta_c$ and $J/\psi$. It is pointed out here that in this picture one might
expect existence of their somewhat heavier strange counterparts, $Z_{cs}$,
decaying to $\eta_c K$ and $J/\psi K$. Some expected properties of such
charmoniumlike strange resonances are discussed that set benchmarks for their
search in the decays of the strange $B_s$ mesons.
| [
{
"created": "Mon, 7 Jan 2019 17:36:03 GMT",
"version": "v1"
},
{
"created": "Mon, 14 Jan 2019 16:56:09 GMT",
"version": "v2"
}
] | 2019-10-16 | [
[
"Voloshin",
"M. B.",
""
]
] | It has been recently suggested that the charged charmoniumlike resonances $Z_c(4100)$ and $Z_c(4200)$ are two states of hadrocharmonium, related by the charm quark spin symmetry in the same way as the lowest charmonium states $\eta_c$ and $J/\psi$. It is pointed out here that in this picture one might expect existence of their somewhat heavier strange counterparts, $Z_{cs}$, decaying to $\eta_c K$ and $J/\psi K$. Some expected properties of such charmoniumlike strange resonances are discussed that set benchmarks for their search in the decays of the strange $B_s$ mesons. |
hep-ph/9409210 | Fredrick Olness | Fredrick I. Olness and Stephan T. Riemersma | Leptoproduction of Heavy Quarks in the Fixed and Variable Flavor Schemes
(CONFERENCE Version) | LaTeX format, 4 pages, 2 figures in uuencoded format. Postscript file
available from ftp://smuphy.physics.smu.edu/usr/ftpdir/pub/papers .
**Presented at the Eighth DPF Meeting, Albuquerque, NM, August, 1994**
(Conference version of SMU-HEP/94-21.) | null | null | SMU-HEP/94-22 | hep-ph | null | We compare the results of the fixed-flavor scheme calculation of Laenen,
Riemersma, Smith and van Neerven with the variable-flavor scheme calculation of
Aivazis, Collins, Olness and Tung for neutral-current (photon-mediated)
heavy-flavor (charm and bottom) production. We compare the structure function
$F_2(x,Q^2)$ throughout phase space, and also analyze the $\mu$-dependenceWe
find that the former calculation is most applicable near threshold, while the
latter works well for asymptotic $Q^2$.
| [
{
"created": "Fri, 2 Sep 1994 01:14:31 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Olness",
"Fredrick I.",
""
],
[
"Riemersma",
"Stephan T.",
""
]
] | We compare the results of the fixed-flavor scheme calculation of Laenen, Riemersma, Smith and van Neerven with the variable-flavor scheme calculation of Aivazis, Collins, Olness and Tung for neutral-current (photon-mediated) heavy-flavor (charm and bottom) production. We compare the structure function $F_2(x,Q^2)$ throughout phase space, and also analyze the $\mu$-dependenceWe find that the former calculation is most applicable near threshold, while the latter works well for asymptotic $Q^2$. |
hep-ph/9912490 | Piet Mulders | A. Bacchetta, M. Boglione, A. Henneman and P.J. Mulders | Bounds on transverse momentum dependent distribution and fragmentation
functions | 5 pages, Revtex, 3 Postscript figures, version with minor changes, to
be published in Physical Review Letters | Phys.Rev.Lett.85:712-715,2000 | 10.1103/PhysRevLett.85.712 | VUTH 99-25 | hep-ph | null | We give bounds on the distribution and fragmentation functions that appear at
leading order in deep inelastic 1-particle inclusive leptoproduction or in
Drell-Yan processes. These bounds simply follow from positivity of the defining
matrix elements and are an important guidance in estimating the magnitude of
the azimuthal and spin asymmetries in these processes.
| [
{
"created": "Thu, 23 Dec 1999 15:26:26 GMT",
"version": "v1"
},
{
"created": "Wed, 14 Jun 2000 14:46:13 GMT",
"version": "v2"
}
] | 2011-07-19 | [
[
"Bacchetta",
"A.",
""
],
[
"Boglione",
"M.",
""
],
[
"Henneman",
"A.",
""
],
[
"Mulders",
"P. J.",
""
]
] | We give bounds on the distribution and fragmentation functions that appear at leading order in deep inelastic 1-particle inclusive leptoproduction or in Drell-Yan processes. These bounds simply follow from positivity of the defining matrix elements and are an important guidance in estimating the magnitude of the azimuthal and spin asymmetries in these processes. |
1501.06806 | Olga Piskounova I. | Olga I. Piskounova | Baryon Production at LHC and Very High Energy Cosmic Ray Spectra | 7 pages with 7 figures, talk given at Symposium on Very High Energy
Cosmic Rays Interactions, 18-22 August 2014, CERN | EPJ Web Conf. 99 (2015) 10007 | 10.1051/epjconf/20159910007 | null | hep-ph astro-ph.HE hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The spectra of baryons at LHC can explain the features of the proton spectra
in cosmic rays (CR). It seems important to study all baryon data that are
available from collider experiments in wide range of energies. Transverse
momentum spectra of baryons from RHIC ($\sqrt(s)$=62 and 200 GeV) and from LHC
($\sqrt(s)$=0.9 and 7 TeV) have been considered. It is seen that the slope of
distributions at low $p_T$'s is changing with energy. The QGSM fit of these
spectra gives the average transverse momenta which behave as $s^{0.06}$ that is
similar to the previously observed behavior of $\Lambda^0$ hyperon spectra. The
change in average transverse momenta that are slowly growing in VHE hadron
interactions at CR detectors cannot cause the "knee" in measured cosmic ray
proton spectra. In addition, the available data on heavy quark hadron
production from LHC-b at $\sqrt{s}$=7 TeV were also studied. The preliminary
dependence of hadron average transverse momenta on their masses at LHC energy
is presented. The possible source of cosmic ray antiparticle-to-particle ratios
that are growing with energy was analyzed in the framework of QGSM, where the
growing ratios are the result of local leading asymmetry between the production
spectra of baryons and antibaryons in the kinematical region of proton target
fragmentation. In the laboratory system of cosmic ray measurements this
spectrum asymmetry will be seen as growing ratio of secondary
antiparticle-to-particle spectra until the certain energy of secondaries. This
conclusion makes the particle production at the sources of very high energy
cosmic protons important, if the interactions with positive target matter would
have place in proximity of these sources.
| [
{
"created": "Tue, 27 Jan 2015 16:21:14 GMT",
"version": "v1"
}
] | 2018-11-12 | [
[
"Piskounova",
"Olga I.",
""
]
] | The spectra of baryons at LHC can explain the features of the proton spectra in cosmic rays (CR). It seems important to study all baryon data that are available from collider experiments in wide range of energies. Transverse momentum spectra of baryons from RHIC ($\sqrt(s)$=62 and 200 GeV) and from LHC ($\sqrt(s)$=0.9 and 7 TeV) have been considered. It is seen that the slope of distributions at low $p_T$'s is changing with energy. The QGSM fit of these spectra gives the average transverse momenta which behave as $s^{0.06}$ that is similar to the previously observed behavior of $\Lambda^0$ hyperon spectra. The change in average transverse momenta that are slowly growing in VHE hadron interactions at CR detectors cannot cause the "knee" in measured cosmic ray proton spectra. In addition, the available data on heavy quark hadron production from LHC-b at $\sqrt{s}$=7 TeV were also studied. The preliminary dependence of hadron average transverse momenta on their masses at LHC energy is presented. The possible source of cosmic ray antiparticle-to-particle ratios that are growing with energy was analyzed in the framework of QGSM, where the growing ratios are the result of local leading asymmetry between the production spectra of baryons and antibaryons in the kinematical region of proton target fragmentation. In the laboratory system of cosmic ray measurements this spectrum asymmetry will be seen as growing ratio of secondary antiparticle-to-particle spectra until the certain energy of secondaries. This conclusion makes the particle production at the sources of very high energy cosmic protons important, if the interactions with positive target matter would have place in proximity of these sources. |
1206.3420 | Singh N.Nimai | Ng. K. Francis, N. Nimai Singh | Validity of quasi-degenerate neutrino mass models and their predictions
on baryogenesis | 17 pages, no figure, poster presentation in the 25th International
Conference on neutrino physics and Astrophysics, Kyoto, Japan, July,2012 | Nuclear Physics B 863 (2012)19-32 | 10.1016/j.nuclphysb.2012.05.017 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Quasi-degenerate neutrino mass models (QDN) which can explain the current
data on neutrino masses and mixings,are studied. In the first part, we study
the effect of CP-phases on QDN mass matrix obeying $\mu-\tau$ symmetry in
normal hierarchical (QD-NH) and inverted hierarchical (QD-IH) patterns.The
numerical predictions are consistent with observed data on solar mixing angle,
absolute neutrino mass parameter consistent with neutrinoless double beta decay
mass parameter and sum of three absolute neutrino masses from cosmological
bound.The neutrino mass matrix is parameterized using only two unknown
parameters. The second part deals with the estimation of observed baryon
asymmetry of the universe. The prediction is nearly consistent with observation
with flavoured thermal leptogenesis scenario. QD-NH model appears to be more
favourable than those of QD-IH models.The present analysis shows that the three
absolute neutrino masses may exhibit quasi-degenerate pattern in nature. They
are far from discrimination at the moment.
| [
{
"created": "Fri, 15 Jun 2012 10:48:03 GMT",
"version": "v1"
}
] | 2012-06-18 | [
[
"Francis",
"Ng. K.",
""
],
[
"Singh",
"N. Nimai",
""
]
] | Quasi-degenerate neutrino mass models (QDN) which can explain the current data on neutrino masses and mixings,are studied. In the first part, we study the effect of CP-phases on QDN mass matrix obeying $\mu-\tau$ symmetry in normal hierarchical (QD-NH) and inverted hierarchical (QD-IH) patterns.The numerical predictions are consistent with observed data on solar mixing angle, absolute neutrino mass parameter consistent with neutrinoless double beta decay mass parameter and sum of three absolute neutrino masses from cosmological bound.The neutrino mass matrix is parameterized using only two unknown parameters. The second part deals with the estimation of observed baryon asymmetry of the universe. The prediction is nearly consistent with observation with flavoured thermal leptogenesis scenario. QD-NH model appears to be more favourable than those of QD-IH models.The present analysis shows that the three absolute neutrino masses may exhibit quasi-degenerate pattern in nature. They are far from discrimination at the moment. |
1206.0264 | Enrico Maria Sessolo | Andrew Fowlie, Malgorzata Kazana, Kamila Kowalska, Shoaib Munir,
Leszek Roszkowski, Enrico Maria Sessolo, Sebastian Trojanowski, Yue-Lin Sming
Tsai | Constrained MSSM favoring new territories: The impact of new LHC limits
and a 125 GeV Higgs boson | 24 pages, 17 figures. PRD-approved version; Higgs bounds case removed
as obsolete in light of the Higgs discovery | Phys.Rev. D86 (2012) 075010 | 10.1103/PhysRevD.86.075010 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present an updated and extended global analysis of the Constrained MSSM
(CMSSM) taking into account new limits on supersymmetry from ~5/fb data sets at
the LHC. In particular, in the case of the razor limit obtained by the CMS
Collaboration we simulate detector efficiency for the experimental analysis and
derive an approximate but accurate likelihood function. We discuss the impact
on the global fit of a possible Higgs boson with mass near 125 GeV, as implied
by recent data, and of a new improved limit on BR(B_s->\mu\mu). We identify
high posterior probability regions of the CMSSM parameters as the
stau-coannihilation and the A-funnel region, with the importance of the latter
now being much larger due to the combined effect of the above three LHC results
and of dark matter relic density. We also find that the focus point region is
now disfavored. Ensuing implications for superpartner masses favor even larger
values than before, and even lower ranges for dark matter spin-independent
cross section, \sigma^{SI}_p<10^{-9} pb. We also find that relatively minor
variations in applying experimental constraints can induce a large shift in the
location of the best-fit point. This puts into question the robustness of
applying the usual chisquare approach to the CMSSM. We discuss the
goodness-of-fit and find that, while it is difficult to calculate a p-value,
the g-2 constraint makes, nevertheless, the overall fit of the CMSSM poor. We
consider a scan without this constraint, and we allow \mu\ to be either
positive or negative. We find that the global fit improves enormously for both
signs of \mu, with a slight preference for \mu<0 caused by a better fit to
BR(b->s\gamma) and BR(B_s->\mu\mu).
| [
{
"created": "Fri, 1 Jun 2012 17:58:44 GMT",
"version": "v1"
},
{
"created": "Tue, 19 Jun 2012 13:42:09 GMT",
"version": "v2"
},
{
"created": "Thu, 5 Jul 2012 14:08:41 GMT",
"version": "v3"
},
{
"created": "Wed, 3 Oct 2012 09:37:26 GMT",
"version": "v4"
}
] | 2013-05-20 | [
[
"Fowlie",
"Andrew",
""
],
[
"Kazana",
"Malgorzata",
""
],
[
"Kowalska",
"Kamila",
""
],
[
"Munir",
"Shoaib",
""
],
[
"Roszkowski",
"Leszek",
""
],
[
"Sessolo",
"Enrico Maria",
""
],
[
"Trojanowski",
"Sebastian"... | We present an updated and extended global analysis of the Constrained MSSM (CMSSM) taking into account new limits on supersymmetry from ~5/fb data sets at the LHC. In particular, in the case of the razor limit obtained by the CMS Collaboration we simulate detector efficiency for the experimental analysis and derive an approximate but accurate likelihood function. We discuss the impact on the global fit of a possible Higgs boson with mass near 125 GeV, as implied by recent data, and of a new improved limit on BR(B_s->\mu\mu). We identify high posterior probability regions of the CMSSM parameters as the stau-coannihilation and the A-funnel region, with the importance of the latter now being much larger due to the combined effect of the above three LHC results and of dark matter relic density. We also find that the focus point region is now disfavored. Ensuing implications for superpartner masses favor even larger values than before, and even lower ranges for dark matter spin-independent cross section, \sigma^{SI}_p<10^{-9} pb. We also find that relatively minor variations in applying experimental constraints can induce a large shift in the location of the best-fit point. This puts into question the robustness of applying the usual chisquare approach to the CMSSM. We discuss the goodness-of-fit and find that, while it is difficult to calculate a p-value, the g-2 constraint makes, nevertheless, the overall fit of the CMSSM poor. We consider a scan without this constraint, and we allow \mu\ to be either positive or negative. We find that the global fit improves enormously for both signs of \mu, with a slight preference for \mu<0 caused by a better fit to BR(b->s\gamma) and BR(B_s->\mu\mu). |
0912.4299 | Francesco Tramontano | Mario Abud, Franco Buccella, Francesco Tramontano | Hints for the existence of hexaquark states in the baryon-antibaryon
sector | 17 pages | Phys.Rev.D81:074018,2010 | 10.1103/PhysRevD.81.074018 | DSF-NA 15-2009, CERN-PH-TH/2009-246 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The discovery of some baryon-antibaryon resonances has led us to consider
3q~3\bar{q} systems as possible candidates. We predict their spectrum in the
framework of a constituent model, where the chromo-magnetic interaction plays
the main role. The relevant parameters are fixed by the present knowledge on
tetraquarks. The emerging scenario complies well with experiment. Besides the
description of the baryon-antibaryon resonances, we find evidence for new
tetraquark states, namely the a0(Y) in the hidden strangeness sector and, in
the cs\bar{c}\bar{s} sector, the Y(4140) and the X(4350). A detailed account of
the spectra and the decay channels is provided for future comparisons with
data.
| [
{
"created": "Tue, 22 Dec 2009 00:22:35 GMT",
"version": "v1"
}
] | 2010-05-12 | [
[
"Abud",
"Mario",
""
],
[
"Buccella",
"Franco",
""
],
[
"Tramontano",
"Francesco",
""
]
] | The discovery of some baryon-antibaryon resonances has led us to consider 3q~3\bar{q} systems as possible candidates. We predict their spectrum in the framework of a constituent model, where the chromo-magnetic interaction plays the main role. The relevant parameters are fixed by the present knowledge on tetraquarks. The emerging scenario complies well with experiment. Besides the description of the baryon-antibaryon resonances, we find evidence for new tetraquark states, namely the a0(Y) in the hidden strangeness sector and, in the cs\bar{c}\bar{s} sector, the Y(4140) and the X(4350). A detailed account of the spectra and the decay channels is provided for future comparisons with data. |
2302.07574 | St\'ephane Peign\'e | St\'ephane Peign\'e | Introduction to color in QCD: Initiation to the birdtrack pictorial
technique | 27 pages, Lectures given at the "6th Chilean School of High Energy
Physics", Valparaiso, January 16-19, 2023 | null | null | null | hep-ph hep-th math-ph math.MP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | These lectures are an elementary introduction to the "birdtrack" color
pictorial technique, a useful tool in QCD. We review the basic rules, discuss
color conservation and infinitesimal color rotations, learn how to project on
partonic color states, how to derive their Casimir charges... and at the same
time learn a little bit of representation theory.
| [
{
"created": "Wed, 15 Feb 2023 10:33:44 GMT",
"version": "v1"
}
] | 2023-02-16 | [
[
"Peigné",
"Stéphane",
""
]
] | These lectures are an elementary introduction to the "birdtrack" color pictorial technique, a useful tool in QCD. We review the basic rules, discuss color conservation and infinitesimal color rotations, learn how to project on partonic color states, how to derive their Casimir charges... and at the same time learn a little bit of representation theory. |
2112.08083 | Motoo Suzuki | Seung J. Lee, Yuichiro Nakai, Motoo Suzuki | High Quality Axion via a Doubly Composite Dynamics | 27 pages, 7 figures | null | 10.1007/JHEP03(2022)038 | null | hep-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We explore a new framework that furnishes a mechanism to simultaneously
address the electroweak naturalness problem and the axion high quality problem.
The framework is based on a doubly composite dynamics where the second
confinement takes place after the CFT encounters the first confinement and the
theory flows into another conformal fixed point. For a calculable example, we
present a holographic dual description of the 4D model via a warped extra
dimension model with three 3-branes. While the hierarchy problem is taken cared
of by the localization of the Higgs fields on the TeV brane just as in the
original Randall-Sundrum model, the Peccei-Quinn (PQ) symmetry is realized as a
gauge symmetry in the bulk of the extra dimension to solve the axion quality
problem. We introduce a 5D scalar field whose potential at the intermediate
brane drives spontaneous breaking of the PQ symmetry. Then, the PQ breaking
scale is given by the scale of the intermediate brane and is naturally small
compared to the Planck scale. The axion bulk profile is significantly
suppressed around the UV brane, which protects the axion from gravitational
violations of the PQ symmetry on the UV brane. Our model genuinely predicts the
existence of the Kaluza-Klein excitations of the QCD axion at around the TeV
scale and relatively light extra Higgs bosons.
| [
{
"created": "Wed, 15 Dec 2021 12:37:58 GMT",
"version": "v1"
}
] | 2022-03-23 | [
[
"Lee",
"Seung J.",
""
],
[
"Nakai",
"Yuichiro",
""
],
[
"Suzuki",
"Motoo",
""
]
] | We explore a new framework that furnishes a mechanism to simultaneously address the electroweak naturalness problem and the axion high quality problem. The framework is based on a doubly composite dynamics where the second confinement takes place after the CFT encounters the first confinement and the theory flows into another conformal fixed point. For a calculable example, we present a holographic dual description of the 4D model via a warped extra dimension model with three 3-branes. While the hierarchy problem is taken cared of by the localization of the Higgs fields on the TeV brane just as in the original Randall-Sundrum model, the Peccei-Quinn (PQ) symmetry is realized as a gauge symmetry in the bulk of the extra dimension to solve the axion quality problem. We introduce a 5D scalar field whose potential at the intermediate brane drives spontaneous breaking of the PQ symmetry. Then, the PQ breaking scale is given by the scale of the intermediate brane and is naturally small compared to the Planck scale. The axion bulk profile is significantly suppressed around the UV brane, which protects the axion from gravitational violations of the PQ symmetry on the UV brane. Our model genuinely predicts the existence of the Kaluza-Klein excitations of the QCD axion at around the TeV scale and relatively light extra Higgs bosons. |
1310.4455 | Patrick Otto Ludl | Patrick Otto Ludl | Current status of constraints on the elements of the neutrino mass
matrix | 7 pages, 1 figure; Talk presented at the XXXVII International
Conference of Theoretical Physics "Matter to the deepest," Ustron, 1-6
September 2013 | null | 10.5506/APhysPolB.44.2339 | UWThPh-2013-29 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We analyse the mass matrix of the three light neutrinos in the basis where
the charged-lepton mass matrix is diagonal and discuss constraints on its
elements for the Majorana and the Dirac case.
| [
{
"created": "Wed, 16 Oct 2013 17:18:18 GMT",
"version": "v1"
}
] | 2015-06-17 | [
[
"Ludl",
"Patrick Otto",
""
]
] | We analyse the mass matrix of the three light neutrinos in the basis where the charged-lepton mass matrix is diagonal and discuss constraints on its elements for the Majorana and the Dirac case. |
2310.07776 | Harri Parkkinen | Kimmo Kainulainen and Harri Parkkinen | Quantum kinetic equations with flavor and particle-antiparticle
coherences for neutrinos | 8 pages, 2 figures. Presented at the 38th International Cosmic Ray
Conference (ICRC2023) | null | null | null | hep-ph astro-ph.HE hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We develop a formalism to model neutrino evolution encompassing both flavor
and particle-antiparticle mixings and decohering collisions. Our results
include a quantum kinetic equation (a set of coupled scalar equations) for the
generalized neutrino density matrix, valid for arbitrary neutrino masses and
kinematics, and a comprehensive set of Feynman rules to compute collision
integrals for coherently evolving states. We expose a novel shell structure
describing the phase space of mixing neutrinos and show how the prior
information on the system can enter into the theory and modify the neutrino
flavor evolution. Potential applications of our results include modelling
neutrino distributions in hot and dense environments and studies of neutrino
mixing effects in colliders and in the early Universe.
| [
{
"created": "Wed, 11 Oct 2023 18:04:30 GMT",
"version": "v1"
}
] | 2023-10-13 | [
[
"Kainulainen",
"Kimmo",
""
],
[
"Parkkinen",
"Harri",
""
]
] | We develop a formalism to model neutrino evolution encompassing both flavor and particle-antiparticle mixings and decohering collisions. Our results include a quantum kinetic equation (a set of coupled scalar equations) for the generalized neutrino density matrix, valid for arbitrary neutrino masses and kinematics, and a comprehensive set of Feynman rules to compute collision integrals for coherently evolving states. We expose a novel shell structure describing the phase space of mixing neutrinos and show how the prior information on the system can enter into the theory and modify the neutrino flavor evolution. Potential applications of our results include modelling neutrino distributions in hot and dense environments and studies of neutrino mixing effects in colliders and in the early Universe. |
0803.0646 | Eugene Levin | E. Levin and J. Miller (Tel Aviv Univ.) | Two parton shower background for associate W Higgs production | 35 pages and 10 figures in eps files | Eur.Phys.J.C61:1-31,2009 | 10.1140/epjc/s10052-009-0961-y | TAUP-2870-08 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The estimates of the background for the associate W Higgs production, which
stems from the two parton shower production. It is about 1 - 2.5 times larger
than the signal. However, this background does not depend on the rapidity
difference between the W and the $b \bar{b}$ pair, while the signal peaks when
the rapidity difference is zero. The detailed calculations for the enhanced
diagrams' contribution to this process, are presented, and it is shown that the
overlapping singularities, being important theoretically, lead to a negligible
contribution for the LHC range of energies
| [
{
"created": "Wed, 5 Mar 2008 12:25:16 GMT",
"version": "v1"
}
] | 2009-07-22 | [
[
"Levin",
"E.",
"",
"Tel Aviv Univ."
],
[
"Miller",
"J.",
"",
"Tel Aviv Univ."
]
] | The estimates of the background for the associate W Higgs production, which stems from the two parton shower production. It is about 1 - 2.5 times larger than the signal. However, this background does not depend on the rapidity difference between the W and the $b \bar{b}$ pair, while the signal peaks when the rapidity difference is zero. The detailed calculations for the enhanced diagrams' contribution to this process, are presented, and it is shown that the overlapping singularities, being important theoretically, lead to a negligible contribution for the LHC range of energies |
1504.06944 | Yong Tang | P. Ko, Wan-Il Park, Yong Tang | Higgs-Portal Dark Matter for GeV Gamma-Ray Excess | 4 pages, 4 figures, proceeding of the 2nd Toyama Workshop on "Higgs
as a Probe of New Physics 2015", 11-15 February 2015 | null | null | null | hep-ph astro-ph.HE | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present Higgs-Portal dark matter (DM) models to explain the reported
Galactic Center GeV gamma-ray excess. Naive effective theories are inconsistent
with direct detection constraint for the relevant parameter range. Simple
extended models with dark gauge symmetries can easily accommodate the gamma-ray
excess through the Higgs-Portal coupling while satisfying various constraints.
| [
{
"created": "Mon, 27 Apr 2015 06:21:19 GMT",
"version": "v1"
}
] | 2015-04-28 | [
[
"Ko",
"P.",
""
],
[
"Park",
"Wan-Il",
""
],
[
"Tang",
"Yong",
""
]
] | We present Higgs-Portal dark matter (DM) models to explain the reported Galactic Center GeV gamma-ray excess. Naive effective theories are inconsistent with direct detection constraint for the relevant parameter range. Simple extended models with dark gauge symmetries can easily accommodate the gamma-ray excess through the Higgs-Portal coupling while satisfying various constraints. |
2305.11205 | Jack Manley | J. Manley and R. Stump and R. Petery and and S. Singh | Searching for Scalar Ultralight Dark Matter with Optical Fibers | null | null | null | null | hep-ph astro-ph.IM physics.ins-det physics.optics quant-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We consider optical fibers as detectors for scalar ultralight dark matter
(UDM) and propose using a fiber-based interferometer to search for scalar UDM
with particle mass in the range $10^{-17} - 10^{-13}$ eV/$c^2$ $\left(10^{-3}-
10 \text{ Hz}\right)$. Composed of a solid core and a hollow core fiber, the
proposed detector would be sensitive to relative oscillations in the fibers'
refractive indices due to scalar UDM-induced modulations in the fine-structure
constant $\alpha$. We predict that, implementing detector arrays or cryogenic
cooling, the proposed optical fiber-based scalar UDM search has the potential
to reach new regions of the parameter space. Such a search would be
particularly well-suited to probe for a Solar halo of dark matter with a
sensitivity exceeding that of previous DM searches over the particle mass range
$7\times 10^{-17} - 2\times 10^{-14}$ eV/$c^2$.
| [
{
"created": "Thu, 18 May 2023 17:23:09 GMT",
"version": "v1"
}
] | 2023-05-22 | [
[
"Manley",
"J.",
""
],
[
"Stump",
"R.",
""
],
[
"Petery",
"R.",
""
],
[
"Singh",
"and S.",
""
]
] | We consider optical fibers as detectors for scalar ultralight dark matter (UDM) and propose using a fiber-based interferometer to search for scalar UDM with particle mass in the range $10^{-17} - 10^{-13}$ eV/$c^2$ $\left(10^{-3}- 10 \text{ Hz}\right)$. Composed of a solid core and a hollow core fiber, the proposed detector would be sensitive to relative oscillations in the fibers' refractive indices due to scalar UDM-induced modulations in the fine-structure constant $\alpha$. We predict that, implementing detector arrays or cryogenic cooling, the proposed optical fiber-based scalar UDM search has the potential to reach new regions of the parameter space. Such a search would be particularly well-suited to probe for a Solar halo of dark matter with a sensitivity exceeding that of previous DM searches over the particle mass range $7\times 10^{-17} - 2\times 10^{-14}$ eV/$c^2$. |
1507.07380 | Jens Krog Mr. | Jens Krog | SM vacuum stability and the Weyl consistency conditions: Counting to
three | 8 pages, 3 figures. Talk given at the Summer School and Workshop on
the Standard Model and Beyond 2013; to appear in the Proceedings of the Corfu
Summer Institute 2014 "School and Workshops on Elementary Particle Physics
and Gravity" Proceedings of the Corfu Summer Institute 2014 | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We demonstrate how a new perturbative ordering may result from the structure
of the Weyl anomaly. Respecting the abelian nature of the Weyl anomaly at the
lowest order enforces the use of beta functions calculated to a different loop
order for different types of couplings. These consistency conditions are found
to be satisfied by the renormalization group equations of the standard model,
and we perform an analysis of the vacuum stability of the Higgs potential
respecting the consistency conditions and compare to the previous results.
Hints toward unknown structure in the standard model renormalization group
equations are found, although the vacuum stability results are in agreement
with previous estimates.
| [
{
"created": "Mon, 27 Jul 2015 12:04:37 GMT",
"version": "v1"
}
] | 2015-07-28 | [
[
"Krog",
"Jens",
""
]
] | We demonstrate how a new perturbative ordering may result from the structure of the Weyl anomaly. Respecting the abelian nature of the Weyl anomaly at the lowest order enforces the use of beta functions calculated to a different loop order for different types of couplings. These consistency conditions are found to be satisfied by the renormalization group equations of the standard model, and we perform an analysis of the vacuum stability of the Higgs potential respecting the consistency conditions and compare to the previous results. Hints toward unknown structure in the standard model renormalization group equations are found, although the vacuum stability results are in agreement with previous estimates. |
hep-ph/9810469 | J. G. Contreras | J. G. Contreras, R. Huerta and L. R. Quintero | The baryon magnetic moments of the octet and the decuplet using
different limits of the SU(3) flavor group | Extended discussion of the decuplet baryons. Final published version | Rev. Mex. Fis. 50(5) (2004) 490-494 | null | null | hep-ph | null | Working within the non relativistic quark model a two parameter fit to the
magnetic moments of baryons is presented. The fit has an excellent $\chi^2$.
The model is based on taking different flavor groups to describe the different
magnetic moments. The selection of which group to assign to each baryon is
guided by the structure of its wavefunction. The model corresponds to assigning
different effective masses to a quark depending on which baryon is being
considered. Using the values extracted from the fit, the magnetic moments of
the $\Omega^-$ and the $\Delta^{++}$ have been predicted and the comparison to
the existing experimental values is quite satisfactory.
| [
{
"created": "Sat, 24 Oct 1998 17:14:41 GMT",
"version": "v1"
},
{
"created": "Mon, 8 Nov 2004 20:09:53 GMT",
"version": "v2"
}
] | 2007-05-23 | [
[
"Contreras",
"J. G.",
""
],
[
"Huerta",
"R.",
""
],
[
"Quintero",
"L. R.",
""
]
] | Working within the non relativistic quark model a two parameter fit to the magnetic moments of baryons is presented. The fit has an excellent $\chi^2$. The model is based on taking different flavor groups to describe the different magnetic moments. The selection of which group to assign to each baryon is guided by the structure of its wavefunction. The model corresponds to assigning different effective masses to a quark depending on which baryon is being considered. Using the values extracted from the fit, the magnetic moments of the $\Omega^-$ and the $\Delta^{++}$ have been predicted and the comparison to the existing experimental values is quite satisfactory. |
hep-ph/9204212 | Marek Karliner | John Ellis, Yitzhak Frishman, Amihay Hanany and Marek Karliner | Quark solitons as constituents of hadrons | 27 p. + 8 figures (not included). Figures are available via ftp, see
instructions in the paper | Nucl.Phys.B382:189-212,1992 | 10.1016/0550-3213(92)90183-C | null | hep-ph | null | We exhibit static solutions of multi-flavour QCD in two dimensions that have
the quantum numbers of baryons and mesons, constructed out of quark and
anti-quark solitons. In isolation the latter solitons have infinite energy,
corresponding to the presence of a string carrying the non-singlet colour flux
off to spatial infinity. When $N_c$ solitons of this type are combined, a
static, finite-energy, colour singlet solution is formed, corresponding to a
baryon. Similarly, static meson solutions are formed out of a soliton and an
anti-soliton of different flavours. The stability of the mesons against
annihilation is ensured by flavour conservation. The static solutions exist
only when the fundamental fields of the bosonized Lagrangian belong to
$U(N_c{\times}N_f)$ rather than to $SU(N_c) \times U(N_f)$. Discussion of
flavour symmetry breaking requires a careful treatment of the normal ordering
ambiguity. Our results can be viewed as a derivation of the constituent quark
model in QCD$_2$, allowing a detailed study of constituent mass generation and
of the heavy quark symmetry.
| [
{
"created": "Tue, 7 Apr 1992 16:02:00 GMT",
"version": "v1"
}
] | 2009-09-11 | [
[
"Ellis",
"John",
""
],
[
"Frishman",
"Yitzhak",
""
],
[
"Hanany",
"Amihay",
""
],
[
"Karliner",
"Marek",
""
]
] | We exhibit static solutions of multi-flavour QCD in two dimensions that have the quantum numbers of baryons and mesons, constructed out of quark and anti-quark solitons. In isolation the latter solitons have infinite energy, corresponding to the presence of a string carrying the non-singlet colour flux off to spatial infinity. When $N_c$ solitons of this type are combined, a static, finite-energy, colour singlet solution is formed, corresponding to a baryon. Similarly, static meson solutions are formed out of a soliton and an anti-soliton of different flavours. The stability of the mesons against annihilation is ensured by flavour conservation. The static solutions exist only when the fundamental fields of the bosonized Lagrangian belong to $U(N_c{\times}N_f)$ rather than to $SU(N_c) \times U(N_f)$. Discussion of flavour symmetry breaking requires a careful treatment of the normal ordering ambiguity. Our results can be viewed as a derivation of the constituent quark model in QCD$_2$, allowing a detailed study of constituent mass generation and of the heavy quark symmetry. |
hep-ph/0204313 | Oleg V. Pavlovsky | O. V. Pavlovsky (ITPM Msu) | Chiral Born-Infeld Theory: topological spherically symmetrical solitons | 7 pages (LaTeX), 3 .eps figures, version to be published in Physics
Letters B | Phys.Lett.B538:202,2002 | 10.1016/S0370-2693(02)01967-6 | null | hep-ph | null | Finite-energy topological spherically symmetrical solutions of Chiral
Born-Infeld Theory are studied. Properties of these solution are obtained, and
a possible physical interpretation is also given.
| [
{
"created": "Fri, 26 Apr 2002 18:30:27 GMT",
"version": "v1"
},
{
"created": "Mon, 13 May 2002 16:14:42 GMT",
"version": "v2"
},
{
"created": "Tue, 9 Jul 2002 12:42:15 GMT",
"version": "v3"
}
] | 2010-11-19 | [
[
"Pavlovsky",
"O. V.",
"",
"ITPM Msu"
]
] | Finite-energy topological spherically symmetrical solutions of Chiral Born-Infeld Theory are studied. Properties of these solution are obtained, and a possible physical interpretation is also given. |
1007.2323 | Peihong Gu | Pei-Hong Gu, Utpal Sarkar | Leptogenesis with Linear, Inverse or Double Seesaw | 6 pages. Published in Phys. Lett. B | Phys.Lett.B694:226-232,2010 | 10.1016/j.physletb.2010.09.062 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The left-right symmetric model with doublet and bi-doublet Higgs scalars can
accommodate linear, inverse or double seesaw for generating small neutrino
masses in the presence of three singlet fermions. If the singlet fermions have
small Majorana masses, they can form three pairs of quasi-degenerate Majorana
fermions with three right-handed neutrinos. The decays of the quasi-degenerate
Majorana fermions can realize the resonant leptogenesis. Alternatively, the
right-handed neutrinos can obtain seesaw suppressed Majorana masses if the
singlet fermions are very heavy. In this case leptogenesis, with or without
resonant effect, is allowed in the decays of the right-handed neutrinos.
| [
{
"created": "Wed, 14 Jul 2010 13:28:14 GMT",
"version": "v1"
},
{
"created": "Thu, 28 Oct 2010 10:45:45 GMT",
"version": "v2"
}
] | 2010-10-29 | [
[
"Gu",
"Pei-Hong",
""
],
[
"Sarkar",
"Utpal",
""
]
] | The left-right symmetric model with doublet and bi-doublet Higgs scalars can accommodate linear, inverse or double seesaw for generating small neutrino masses in the presence of three singlet fermions. If the singlet fermions have small Majorana masses, they can form three pairs of quasi-degenerate Majorana fermions with three right-handed neutrinos. The decays of the quasi-degenerate Majorana fermions can realize the resonant leptogenesis. Alternatively, the right-handed neutrinos can obtain seesaw suppressed Majorana masses if the singlet fermions are very heavy. In this case leptogenesis, with or without resonant effect, is allowed in the decays of the right-handed neutrinos. |
1308.4331 | Guido Macorini Dr | M. Beccaria, G. Macorini, G. Panizzo and C. Verzegnassi | New Physics signals from measurable polarization asymmetries at LHC | typo corrected | null | 10.1016/j.physletb.2014.01.010 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We propose a new type of Z polarization asymmetry in bottom-Z production at
LHC that should be realistically measurable and would provide the determination
of the so-called $A_b$ parameter, whose available measured value still appears
to be in disagreement with the Standard Model prediction. This polarization can
be measured independently of a possible existence of Supersymmetry. If
Supersymmetry is found, a second polarization, i.e. the top longitudinal
polarization in top-charged Higgs production, would neatly identify the $\tan
\beta$ parameter. In this case, the value of $A_b$ should be in agreement with
the Standard Model. If Supersymmetry does not exist, a residual disagreement of
$A_b$ from the Standard Model prediction would be a clean signal of New Physics
of "non Supersymmetric" origin.
| [
{
"created": "Tue, 20 Aug 2013 15:45:56 GMT",
"version": "v1"
},
{
"created": "Wed, 21 Aug 2013 16:15:32 GMT",
"version": "v2"
}
] | 2015-06-16 | [
[
"Beccaria",
"M.",
""
],
[
"Macorini",
"G.",
""
],
[
"Panizzo",
"G.",
""
],
[
"Verzegnassi",
"C.",
""
]
] | We propose a new type of Z polarization asymmetry in bottom-Z production at LHC that should be realistically measurable and would provide the determination of the so-called $A_b$ parameter, whose available measured value still appears to be in disagreement with the Standard Model prediction. This polarization can be measured independently of a possible existence of Supersymmetry. If Supersymmetry is found, a second polarization, i.e. the top longitudinal polarization in top-charged Higgs production, would neatly identify the $\tan \beta$ parameter. In this case, the value of $A_b$ should be in agreement with the Standard Model. If Supersymmetry does not exist, a residual disagreement of $A_b$ from the Standard Model prediction would be a clean signal of New Physics of "non Supersymmetric" origin. |
1211.2272 | Pedro Fernando Simoes Costa | M. C. Ruivo, Pedro Costa, C. A. de Sousa | Effects of entanglement and instanton suppression at finite temperature
in a SU(2) EPNJL model with anomaly | 19 pages, 4 figures; PRD version | Phys.Rev. D86 (2012) 116007 | 10.1103/PhysRevD.86.116007 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We investigate the phase transitions characterized by deconfinement and
restoration of chiral and axial symmetries,at finite temperature, in the
framework of QCD inspired models. We compare the results obtained in the SU(2)
Polyakov-Nambu-Jona-Lasinio model with anomaly and in its extended version, the
Entangled Polyakov-Nambu-Jona-Lasinio model. In the last version, four-quark
vertices with entanglement between the chiral condensate and the Polyakov loop
are considered. The thermodynamics of the phase transitions, the meson
spectrum, and in particular the convergence of axial and chiral partners, will
be analyzed, as well as the topological susceptibility. We find that an
explicit temperature dependence of the coupling vertices is necessary in both
models in order to have effective restoration of the U$_A$(1) symmetry.
| [
{
"created": "Sat, 10 Nov 2012 00:42:15 GMT",
"version": "v1"
},
{
"created": "Sun, 12 May 2013 11:55:09 GMT",
"version": "v2"
}
] | 2013-05-14 | [
[
"Ruivo",
"M. C.",
""
],
[
"Costa",
"Pedro",
""
],
[
"de Sousa",
"C. A.",
""
]
] | We investigate the phase transitions characterized by deconfinement and restoration of chiral and axial symmetries,at finite temperature, in the framework of QCD inspired models. We compare the results obtained in the SU(2) Polyakov-Nambu-Jona-Lasinio model with anomaly and in its extended version, the Entangled Polyakov-Nambu-Jona-Lasinio model. In the last version, four-quark vertices with entanglement between the chiral condensate and the Polyakov loop are considered. The thermodynamics of the phase transitions, the meson spectrum, and in particular the convergence of axial and chiral partners, will be analyzed, as well as the topological susceptibility. We find that an explicit temperature dependence of the coupling vertices is necessary in both models in order to have effective restoration of the U$_A$(1) symmetry. |
hep-ph/0007204 | Ivan Gaidaenko | I. V. Gaidaenko, V. A. Novikov, M. I. Vysotsky | On the production of a lepton pair in the collision of ultrarelativistic
neutral particle with nonzero magnetic moment with nuclei | 9 pages, 4 figures, numerical estimates are improved | Phys.Lett. B497 (2001) 49-54 | 10.1016/S0370-2693(00)01305-8 | null | hep-ph | null | Explicit formulas which describe muon pair production in reaction $\gamma\nu
\to \mu^+ \mu^- \nu$ through neutrino magnetic moment are obtained and used to
derive in the leading approximation cross section of muon pair production in
$\nu N$-scattering due to neutrino magnetic moment. This cross section appears
to be proportional to $\log^4 E_{\nu}$. Comparison with experimental data on
tridents production provides an upper bound $\mu_{\nu_{\mu}} < 4*10^{-8}
\mu_B$, which is approximately two orders of magnitude weaker than that from
$\nu_{\mu}e$ elastic scattering data.
| [
{
"created": "Wed, 19 Jul 2000 10:57:51 GMT",
"version": "v1"
},
{
"created": "Wed, 4 Oct 2000 12:17:16 GMT",
"version": "v2"
},
{
"created": "Tue, 24 Oct 2000 11:54:01 GMT",
"version": "v3"
}
] | 2009-10-31 | [
[
"Gaidaenko",
"I. V.",
""
],
[
"Novikov",
"V. A.",
""
],
[
"Vysotsky",
"M. I.",
""
]
] | Explicit formulas which describe muon pair production in reaction $\gamma\nu \to \mu^+ \mu^- \nu$ through neutrino magnetic moment are obtained and used to derive in the leading approximation cross section of muon pair production in $\nu N$-scattering due to neutrino magnetic moment. This cross section appears to be proportional to $\log^4 E_{\nu}$. Comparison with experimental data on tridents production provides an upper bound $\mu_{\nu_{\mu}} < 4*10^{-8} \mu_B$, which is approximately two orders of magnitude weaker than that from $\nu_{\mu}e$ elastic scattering data. |
0908.0457 | Sergey Afonin | S. S. Afonin | A five-dimensional toy-model for light hadron excitations | 10 pages, to be published in Int. J. Mod. Phys. A | Int.J.Mod.Phys.A25:3933-3940,2010 | 10.1142/S0217751X10050196 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In the usual holographic approach to QCD, the meson spectrum is generated due
to a non-trivial 5-dimensional background. We propose an alternative
5-dimensional scenario in which the spectrum emerges due to coupling to a
scalar field whose condensation is supposed to be dual to the formation of
gluon condensate and mimics the scale anomaly in QCD. The spectrum of model has
finite number of discrete states plus continuum and reveals a Regge-like
behavior in the strong coupling regime.
| [
{
"created": "Tue, 4 Aug 2009 15:05:54 GMT",
"version": "v1"
},
{
"created": "Thu, 17 Jun 2010 11:20:53 GMT",
"version": "v2"
}
] | 2014-11-20 | [
[
"Afonin",
"S. S.",
""
]
] | In the usual holographic approach to QCD, the meson spectrum is generated due to a non-trivial 5-dimensional background. We propose an alternative 5-dimensional scenario in which the spectrum emerges due to coupling to a scalar field whose condensation is supposed to be dual to the formation of gluon condensate and mimics the scale anomaly in QCD. The spectrum of model has finite number of discrete states plus continuum and reveals a Regge-like behavior in the strong coupling regime. |
hep-ph/0506145 | Srubabati Goswami | Raj Gandhi, Pomita Ghoshal, Srubabati Goswami, Poonam Mehta, S Uma
Sankar | Probing the Neutrino Mass Hierarchy via Atmospheric $\nu_\mu + \bar
\nu_\mu$ Survival Rates in Megaton Water Cerenkov Detectors | 18 pages, 4 figures. Sigma sensitivity to the mass hierarchy has been
recalculated using the difference in expected events in matter for normal and
inverted hierarchies. In addition to absolute event rates, sensitivities for
up/down ratios have also been calculated. Figures and tables updated to
incorporate the new results. Substantial rewriting of text with clarifying
comments. References added | null | null | null | hep-ph hep-ex | null | The neutrino mass hierarchy, presently unknown, is a powerful discriminator
among various classes of unification theories. We show that the $\nu_{\mu} +
\bar{\nu}_\mu$ survival rate in atmospheric events can provide a novel method
of determining the hierarchy in megaton water Cerenkov detectors. For
pathlength and energy ranges relevant to atmospheric neutrinos,this rate
obtains significant matter sensitive variations not only from resonant matter
effects in $P_{\mu e}$ but also from those in $P_{\mu\tau}$. We calculate the
expected muon event rates in the case of matter oscillations with both natural
and inverted hierarchy.We identify the energy and pathlength ranges for which
resonant matter effects can lead to observable differences between the above
two cases. We also estimate the exposure time required to observe this
difference and determine the sign of $\Delta_{31}$ in a statistically
significant manner.
| [
{
"created": "Wed, 15 Jun 2005 15:12:16 GMT",
"version": "v1"
},
{
"created": "Thu, 4 Aug 2005 08:33:21 GMT",
"version": "v2"
}
] | 2007-05-23 | [
[
"Gandhi",
"Raj",
""
],
[
"Ghoshal",
"Pomita",
""
],
[
"Goswami",
"Srubabati",
""
],
[
"Mehta",
"Poonam",
""
],
[
"Sankar",
"S Uma",
""
]
] | The neutrino mass hierarchy, presently unknown, is a powerful discriminator among various classes of unification theories. We show that the $\nu_{\mu} + \bar{\nu}_\mu$ survival rate in atmospheric events can provide a novel method of determining the hierarchy in megaton water Cerenkov detectors. For pathlength and energy ranges relevant to atmospheric neutrinos,this rate obtains significant matter sensitive variations not only from resonant matter effects in $P_{\mu e}$ but also from those in $P_{\mu\tau}$. We calculate the expected muon event rates in the case of matter oscillations with both natural and inverted hierarchy.We identify the energy and pathlength ranges for which resonant matter effects can lead to observable differences between the above two cases. We also estimate the exposure time required to observe this difference and determine the sign of $\Delta_{31}$ in a statistically significant manner. |
hep-ph/0407225 | Giulia Ricciardi | Ugo Aglietti and Giulia Ricciardi | A model for next-to-leading order threshold resummed form factors | 13 pages, 7 figures; enlarged version, sections added, typos
corrected | Phys.Rev. D70 (2004) 114008 | 10.1103/PhysRevD.70.114008 | DSFNA/14/04, ROME1/1377/04 | hep-ph | null | We present a model for next-to-leading order resummed threshold form factors
based on a time-like coupling recently introduced in the framework of small x
physics. Improved expressions for the form factors in N-space are obtained
which are not plagued by Landau-pole singularities, as the included absorptive
effects -- usually neglected -- act as regulators. The physical reason is that,
because of faster decay of gluon jets, there is not enough resolution time to
observe the Landau pole. Our form factors reduce to the standard ones when the
absorptive parts related to the coupling are neglected. The inverse transform
from N-space to x-space can be done directly without any prescription and we
obtain analytical expressions for the form factors, which are well defined in
all x-space.
| [
{
"created": "Tue, 20 Jul 2004 13:15:52 GMT",
"version": "v1"
},
{
"created": "Tue, 2 Nov 2004 16:02:25 GMT",
"version": "v2"
},
{
"created": "Tue, 23 Nov 2004 21:25:50 GMT",
"version": "v3"
}
] | 2016-09-06 | [
[
"Aglietti",
"Ugo",
""
],
[
"Ricciardi",
"Giulia",
""
]
] | We present a model for next-to-leading order resummed threshold form factors based on a time-like coupling recently introduced in the framework of small x physics. Improved expressions for the form factors in N-space are obtained which are not plagued by Landau-pole singularities, as the included absorptive effects -- usually neglected -- act as regulators. The physical reason is that, because of faster decay of gluon jets, there is not enough resolution time to observe the Landau pole. Our form factors reduce to the standard ones when the absorptive parts related to the coupling are neglected. The inverse transform from N-space to x-space can be done directly without any prescription and we obtain analytical expressions for the form factors, which are well defined in all x-space. |
hep-ph/9908525 | Mihail Tchijov | M. V. Chizhov and D. P. Kirilova | On Neutrino-Mixing-Generated Lepton Asymmetry and the Primordial
Helium-4 Abundance | 13 pages, 2 eps figures | null | null | IC/99/112 | hep-ph | null | In this article we discuss lepton asymmetry effect on BBN with neutrino
oscillations. We argue that asymmetry much smaller than 0.01, although not big
enough to influence directly the nucleosynthesis kinetics, can effect
considerably BBN indirectly via neutrino oscillations. Namely, it distorts
neutrino spectrum and changes neutrino density evolution and the pattern of
oscillations (either suppressing or enhancing them), which in turn effect the
primordial synthesis of elements. We show that the results of the paper X. Shi
et al., Phys. Rev. D 60, 063002 (1999), based on the assumption that only L >
0.01 will influence helium-4 production, are not valid. Instead, the precise
constraints on neutrino mixing parameters from BBN are presented.
| [
{
"created": "Tue, 31 Aug 1999 18:46:40 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Chizhov",
"M. V.",
""
],
[
"Kirilova",
"D. P.",
""
]
] | In this article we discuss lepton asymmetry effect on BBN with neutrino oscillations. We argue that asymmetry much smaller than 0.01, although not big enough to influence directly the nucleosynthesis kinetics, can effect considerably BBN indirectly via neutrino oscillations. Namely, it distorts neutrino spectrum and changes neutrino density evolution and the pattern of oscillations (either suppressing or enhancing them), which in turn effect the primordial synthesis of elements. We show that the results of the paper X. Shi et al., Phys. Rev. D 60, 063002 (1999), based on the assumption that only L > 0.01 will influence helium-4 production, are not valid. Instead, the precise constraints on neutrino mixing parameters from BBN are presented. |
1810.02205 | Xianhui Zhong | Kai-Lei Wang, Qi-Fang L\"u, Xian-Hui Zhong | Interpretation of the newly observed $\Sigma_b(6097)^{\pm}$ and
$\Xi_b(6227)^-$ states as the $P$-wave bottom baryons | 7 pages. arXiv admin note: text overlap with arXiv:1709.04268 | Phys. Rev. D 99, 014011 (2019) | 10.1103/PhysRevD.99.014011 | null | hep-ph hep-ex | http://creativecommons.org/licenses/by/4.0/ | The strong decays of the $P$-wave $\Sigma_b$, $\Xi_b'$ and $\Omega_b$ baryons
are investigated with a constituent quark model in the $j$-$j$ coupling scheme.
The results show that the newly observed $\Sigma_b(6097)$ and $\Xi_b(6227)$
states by the LHCb collaboration can be assigned as the $\lambda$-mode $P$-wave
singly bottom baryons. Given the heavy quark symmetry, both the
$\Sigma_b(6097)$ and $\Xi_b(6227)$ states favor the light spin $j=2$ states
with spin-parity numbers $J^P=3/2^-$ or $J^P=5/2^-$. More $P$-wave singly
bottom baryons are most likely to be observed in future experiments for their
relatively narrow width.
| [
{
"created": "Wed, 3 Oct 2018 14:28:22 GMT",
"version": "v1"
},
{
"created": "Sat, 29 Dec 2018 07:40:18 GMT",
"version": "v2"
}
] | 2019-01-16 | [
[
"Wang",
"Kai-Lei",
""
],
[
"Lü",
"Qi-Fang",
""
],
[
"Zhong",
"Xian-Hui",
""
]
] | The strong decays of the $P$-wave $\Sigma_b$, $\Xi_b'$ and $\Omega_b$ baryons are investigated with a constituent quark model in the $j$-$j$ coupling scheme. The results show that the newly observed $\Sigma_b(6097)$ and $\Xi_b(6227)$ states by the LHCb collaboration can be assigned as the $\lambda$-mode $P$-wave singly bottom baryons. Given the heavy quark symmetry, both the $\Sigma_b(6097)$ and $\Xi_b(6227)$ states favor the light spin $j=2$ states with spin-parity numbers $J^P=3/2^-$ or $J^P=5/2^-$. More $P$-wave singly bottom baryons are most likely to be observed in future experiments for their relatively narrow width. |
0912.4894 | Edward Shuryak | Raffaele Millo and Edward Shuryak | Macroscopic Chirality Fluctuations in Heavy Ion Collisions should induce
CP forbidden Decays | null | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | f large fluctuations of quark chirality occur in heavy ion collisions, they
result in macroscopic CP-odd "spots" of the so called theta-vacua, with a
non-zero $\theta(x)$. We consider particular decays of mesons, CP-forbidden in
the vacuum with zero $\theta$, like $\eta\to \pi\pi$. We evaluate their rates
for such decays near hadronic freezeout. These rates, as well as charge
asymmetries already observed, are proportional to square of the CP-violating
parameter $<\theta^2>$ averaged over the fireball and events. With such input,
we found that the forbidden decay rates are likely to be orders of magnitude
larger than CP-allowed ones. We further estimated that up to about one per mill
of $\eta$ mesons produced in heavy ion collisions should decay in this way. We
further discuss how those can be observed. We argue using STAR data on charge
asymmetries for AuAu and CuCu collisions that the size of CP-odd spots at
freezeout is as large as Cu nuclei: this fortunate fact (not explained so far
by itself) suggests that the two-pion invariant mass is modified by only about
a percent, which is comparable to experimental resolution. If so, we think
experimental observation of these decays is within the reach of current
dataset. If those decays are found, it would confirm that CP-odd interpretation
of charge asyymetry is correct, even without complication related to geometry,
impact parameter or magnetic field induced on the fireball.
| [
{
"created": "Thu, 24 Dec 2009 17:45:42 GMT",
"version": "v1"
}
] | 2009-12-25 | [
[
"Millo",
"Raffaele",
""
],
[
"Shuryak",
"Edward",
""
]
] | f large fluctuations of quark chirality occur in heavy ion collisions, they result in macroscopic CP-odd "spots" of the so called theta-vacua, with a non-zero $\theta(x)$. We consider particular decays of mesons, CP-forbidden in the vacuum with zero $\theta$, like $\eta\to \pi\pi$. We evaluate their rates for such decays near hadronic freezeout. These rates, as well as charge asymmetries already observed, are proportional to square of the CP-violating parameter $<\theta^2>$ averaged over the fireball and events. With such input, we found that the forbidden decay rates are likely to be orders of magnitude larger than CP-allowed ones. We further estimated that up to about one per mill of $\eta$ mesons produced in heavy ion collisions should decay in this way. We further discuss how those can be observed. We argue using STAR data on charge asymmetries for AuAu and CuCu collisions that the size of CP-odd spots at freezeout is as large as Cu nuclei: this fortunate fact (not explained so far by itself) suggests that the two-pion invariant mass is modified by only about a percent, which is comparable to experimental resolution. If so, we think experimental observation of these decays is within the reach of current dataset. If those decays are found, it would confirm that CP-odd interpretation of charge asyymetry is correct, even without complication related to geometry, impact parameter or magnetic field induced on the fireball. |
hep-ph/0501260 | Boris Kopeliovich | B.Z.Kopeliovich, J.Nemchik, I.K.Potashnikova, M.B.Johnson, Ivan
Schmidt | Breakdown of QCD factorization at large Feynman x | 12 pages Latex, 8 figures (only technical corrections in the
replacement) | Phys.Rev. C72 (2005) 054606 | 10.1103/PhysRevC.72.054606 | USM-TH-166 | hep-ph nucl-th | null | Recent measurements by the BRAHMS collaboration of high-pT hadron production
at forward rapidities at RHIC found the relative production rate(d-Au)/(p-p) to
be suppressed, rather than enhanced. Examining other known reactions (forward
production of light hadrons, the Drell-Yan process, heavy flavor production,
etc.), one notes that all of these display a similar property, namely, their
cross sections in nuclei are suppressed at large xF. Since this is the region
where x2 is minimal, it is tempting to interpret this as a manifestation of
coherence, or of a color glass condensate, whereas it is actually a simple
consequence of energy conservation and takes place even at low energies. We
demonstrate that in all these reactions there is a common suppression mechanism
that can be viewed, alternatively, as a consequence of a reduced survival
probability for large rapidity gap processes in nuclei, Sudakov suppression, an
enhanced resolution of higher Fock states by nuclei, or an effective energy
loss that rises linearly with energy. Our calculations agree with data.
| [
{
"created": "Thu, 27 Jan 2005 18:01:11 GMT",
"version": "v1"
},
{
"created": "Fri, 28 Jan 2005 16:37:51 GMT",
"version": "v2"
},
{
"created": "Mon, 6 Jun 2005 16:24:42 GMT",
"version": "v3"
}
] | 2009-11-11 | [
[
"Kopeliovich",
"B. Z.",
""
],
[
"Nemchik",
"J.",
""
],
[
"Potashnikova",
"I. K.",
""
],
[
"Johnson",
"M. B.",
""
],
[
"Schmidt",
"Ivan",
""
]
] | Recent measurements by the BRAHMS collaboration of high-pT hadron production at forward rapidities at RHIC found the relative production rate(d-Au)/(p-p) to be suppressed, rather than enhanced. Examining other known reactions (forward production of light hadrons, the Drell-Yan process, heavy flavor production, etc.), one notes that all of these display a similar property, namely, their cross sections in nuclei are suppressed at large xF. Since this is the region where x2 is minimal, it is tempting to interpret this as a manifestation of coherence, or of a color glass condensate, whereas it is actually a simple consequence of energy conservation and takes place even at low energies. We demonstrate that in all these reactions there is a common suppression mechanism that can be viewed, alternatively, as a consequence of a reduced survival probability for large rapidity gap processes in nuclei, Sudakov suppression, an enhanced resolution of higher Fock states by nuclei, or an effective energy loss that rises linearly with energy. Our calculations agree with data. |
hep-ph/0510404 | Tetsuo Shindou | S. T. Petcov, W. Rodejohann, T. Shindou, and Y. Takanishi | The See-Saw Mechanism, Neutrino Yukawa Couplings, LFV Decays l_i to l_j
+ gamma and Leptogenesis | 25 pages, 9 figures; typos corrected, few clarifying comments and one
figure added; version submitted for publication | Nucl.Phys. B739 (2006) 208-233 | 10.1016/j.nuclphysb.2006.01.034 | SISSA 78/2005/EP, IC/2005/102, TUM-HEP-606/05 | hep-ph | null | The LFV charged lepton decays mu to e + gamma, tau to e + gamma and tau to mu
+ gamma and thermal leptogenesis are analysed in the MSSM with see-saw
mechanism of neutrino mass generation and soft SUSY breaking with universal
boundary conditions. The case of hierarchical heavy Majorana neutrino mass
spectrum, M_1 << M_2 << M_3, is investigated. Leptogenesis requires M_1 > 10^9
GeV. Considering the natural range of values of the heaviest right-handed
Majorana neutrino mass, M_3 > 5*10^{13} GeV, and assuming that the soft SUSY
breaking universal gaugino and/or scalar masses have values in the range of few
100 GeV, we derive the combined constraints, which the existing stringent upper
limit on the mu to e + gamma decay rate and the requirement of successful
thermal leptogenesis impose on the neutrino Yukawa couplings, heavy Majorana
neutrino masses and SUSY parameters. Results for the three possible types of
light neutrino mass spectrum -- normal and inverted hierarchical and
quasi-degenerate -- are obtained.
| [
{
"created": "Mon, 31 Oct 2005 07:50:49 GMT",
"version": "v1"
},
{
"created": "Mon, 21 Nov 2005 17:52:51 GMT",
"version": "v2"
}
] | 2010-04-05 | [
[
"Petcov",
"S. T.",
""
],
[
"Rodejohann",
"W.",
""
],
[
"Shindou",
"T.",
""
],
[
"Takanishi",
"Y.",
""
]
] | The LFV charged lepton decays mu to e + gamma, tau to e + gamma and tau to mu + gamma and thermal leptogenesis are analysed in the MSSM with see-saw mechanism of neutrino mass generation and soft SUSY breaking with universal boundary conditions. The case of hierarchical heavy Majorana neutrino mass spectrum, M_1 << M_2 << M_3, is investigated. Leptogenesis requires M_1 > 10^9 GeV. Considering the natural range of values of the heaviest right-handed Majorana neutrino mass, M_3 > 5*10^{13} GeV, and assuming that the soft SUSY breaking universal gaugino and/or scalar masses have values in the range of few 100 GeV, we derive the combined constraints, which the existing stringent upper limit on the mu to e + gamma decay rate and the requirement of successful thermal leptogenesis impose on the neutrino Yukawa couplings, heavy Majorana neutrino masses and SUSY parameters. Results for the three possible types of light neutrino mass spectrum -- normal and inverted hierarchical and quasi-degenerate -- are obtained. |
1407.4747 | Giancarlo Ferrera | Giancarlo Ferrera (Milan U. and INFN, Milan), Massimiliano Grazzini
(Zurich U.), Francesco Tramontano (Naples U. and INFN, Naples) | Associated ZH production at hadron colliders: the fully differential
NNLO QCD calculation | 10 pages, 2 figures | null | 10.1016/j.physletb.2014.11.040 | IFUM-1031-FT, ZU-TH 23/14 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We consider Standard Model Higgs boson production in association with a Z
boson in hadron collisions. We present a fully exclusive computation of QCD
radiative corrections up to next-to-next-to-leading order (NNLO). Our
calculation includes the Higgs boson decay to bottom quarks (b) in
next-to-leading order QCD and the leptonic decay of the Z boson with
finite-width effects and spin correlations. The computation is implemented in a
parton level Monte Carlo program that makes possible to consider arbitrary
kinematical cuts on the final-state leptons, the b jets and the associated QCD
radiation, and to compute the corresponding distributions in the form of bin
histograms. We assess the impact of QCD radiative effects in the boosted
kinematics at the LHC and show that the inclusion of the NNLO corrections is
crucial to control the pT spectrum of the Higgs boson candidate.
| [
{
"created": "Thu, 17 Jul 2014 17:33:18 GMT",
"version": "v1"
}
] | 2015-06-22 | [
[
"Ferrera",
"Giancarlo",
"",
"Milan U. and INFN, Milan"
],
[
"Grazzini",
"Massimiliano",
"",
"Zurich U."
],
[
"Tramontano",
"Francesco",
"",
"Naples U. and INFN, Naples"
]
] | We consider Standard Model Higgs boson production in association with a Z boson in hadron collisions. We present a fully exclusive computation of QCD radiative corrections up to next-to-next-to-leading order (NNLO). Our calculation includes the Higgs boson decay to bottom quarks (b) in next-to-leading order QCD and the leptonic decay of the Z boson with finite-width effects and spin correlations. The computation is implemented in a parton level Monte Carlo program that makes possible to consider arbitrary kinematical cuts on the final-state leptons, the b jets and the associated QCD radiation, and to compute the corresponding distributions in the form of bin histograms. We assess the impact of QCD radiative effects in the boosted kinematics at the LHC and show that the inclusion of the NNLO corrections is crucial to control the pT spectrum of the Higgs boson candidate. |
hep-ph/9608369 | Kotikov Anatoly | A.V.Kotikov (ENSLAPP & JINR) and D.V.Peshekhonov (JINR) | On the $Q^2$ Dependence of Asymmetry $A_1$ | LATEX, 3 pages, procl.sty included; talk at DIS96, Roma, April 1996 | null | null | null | hep-ph | null | We analyse the proton and deutron data on spin dependent asymmetry
$A_1(x,Q^2)$ supposing the DIS structure functions $g_1(x,Q^2)$ and
$F_3(x,Q^2)$ have the similar $Q^2$-dependence.
| [
{
"created": "Mon, 19 Aug 1996 17:43:24 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Kotikov",
"A. V.",
"",
"ENSLAPP & JINR"
],
[
"Peshekhonov",
"D. V.",
"",
"JINR"
]
] | We analyse the proton and deutron data on spin dependent asymmetry $A_1(x,Q^2)$ supposing the DIS structure functions $g_1(x,Q^2)$ and $F_3(x,Q^2)$ have the similar $Q^2$-dependence. |
1706.08726 | Gergely Mark\'o | Gergely Mark\'o, Urko Reinosa and Zsolt Sz\'ep | Pad\'e approximants and analytic continuation of Euclidean Phi-derivable
approximations | 20 pages, 8 figures, uses RevTeX 4-1 | null | 10.1103/PhysRevD.96.036002 | null | hep-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We investigate the Pad\'e approximation method for the analytic continuation
of numerical data and its ability to access, from the Euclidean propagator,
both the spectral function and part of the physical information hidden in the
second Riemann sheet. We test this method using various benchmarks at zero
temperature: a simple perturbative approximation as well as the two-loop
Phi-derivable approximation. The analytic continuation method is then applied
to Euclidean data previously obtained in the O(4) symmetric model (within a
given renormalization scheme) to assess the difference between zero-momentum
and pole masses, which is in general a difficult question to answer within
nonperturbative approaches such as the Phi-derivable expansion scheme.
| [
{
"created": "Tue, 27 Jun 2017 08:46:13 GMT",
"version": "v1"
}
] | 2017-09-13 | [
[
"Markó",
"Gergely",
""
],
[
"Reinosa",
"Urko",
""
],
[
"Szép",
"Zsolt",
""
]
] | We investigate the Pad\'e approximation method for the analytic continuation of numerical data and its ability to access, from the Euclidean propagator, both the spectral function and part of the physical information hidden in the second Riemann sheet. We test this method using various benchmarks at zero temperature: a simple perturbative approximation as well as the two-loop Phi-derivable approximation. The analytic continuation method is then applied to Euclidean data previously obtained in the O(4) symmetric model (within a given renormalization scheme) to assess the difference between zero-momentum and pole masses, which is in general a difficult question to answer within nonperturbative approaches such as the Phi-derivable expansion scheme. |
1105.3679 | Sven Faller | Sven Faller, Thomas Mannel and Sascha Turczyk | Limits on New Physics from exclusive $B \to D^{(*)}\ell \bar\nu$ Decays | 7 pages | Phys.Rev.D84:014022,2011 | 10.1103/PhysRevD.84.014022 | SI-HEP-2010-06 | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We consider the exclusive decays $B \to D^{(*)}\,\ell \bar\nu$ and study the
effect of non $V-A$ structures on the observables. We extend the standard model
hadronic current by additional right-handed vector as well as left- and
right-handed scalar and tensor contributions and calculate the decay rates
including the perturbative corrections up to order $\alpha_s$. Using the data
of the exclusive semileptonic $b \to c $ decays and recent calculations of the
form factors at the non-recoil point we discuss the constraints to the wrong
helicity admixtures in the hadronic current.
| [
{
"created": "Wed, 18 May 2011 16:20:56 GMT",
"version": "v1"
}
] | 2011-08-09 | [
[
"Faller",
"Sven",
""
],
[
"Mannel",
"Thomas",
""
],
[
"Turczyk",
"Sascha",
""
]
] | We consider the exclusive decays $B \to D^{(*)}\,\ell \bar\nu$ and study the effect of non $V-A$ structures on the observables. We extend the standard model hadronic current by additional right-handed vector as well as left- and right-handed scalar and tensor contributions and calculate the decay rates including the perturbative corrections up to order $\alpha_s$. Using the data of the exclusive semileptonic $b \to c $ decays and recent calculations of the form factors at the non-recoil point we discuss the constraints to the wrong helicity admixtures in the hadronic current. |
1306.3759 | Tomoya Hayata | Tomoya Hayata | Dynamical Mass Generation of Vector Mesons from QCD Trace Anomaly | 5 pages, 1 figure. v2: published version | null | 10.1103/PhysRevD.88.036007 | RIKEN-QHP-87 | hep-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Mass formulas for the light-vector mesons written in terms of the gluon
condensate i.e., the trace anomaly in quantum chromodynamics (QCD), are derived
on the basis of finite energy QCD sum rules. We utilize sum rules with $s^n$
and $s^{n+1/2}$ weights, which relate the energy-weighted spectral sums to the
vacuum expectation values of certain commutation relations. After evaluating
the commutation relations, the sum rules with $s^n$ weights are reduced to the
familiar ones obtained from the operator product expansion (OPE). On the other
hand, the sum rules with $s^{n+1/2}$ weights cannot be derived from OPE. They
give new relations between the spectral sums and QCD vacuum fluctuations. To
derive simple mass formula, we adopt the pole + continuum Ansatz for the
spectral function, and solve coupled equations given by the sum rules with
$s^{0,1}$ weights and the new sum rule with $s^{1/2}$ weight. Application of
our approach to the axial-vector meson is also discussed.
| [
{
"created": "Mon, 17 Jun 2013 07:54:14 GMT",
"version": "v1"
},
{
"created": "Fri, 6 Sep 2013 02:30:19 GMT",
"version": "v2"
}
] | 2015-06-16 | [
[
"Hayata",
"Tomoya",
""
]
] | Mass formulas for the light-vector mesons written in terms of the gluon condensate i.e., the trace anomaly in quantum chromodynamics (QCD), are derived on the basis of finite energy QCD sum rules. We utilize sum rules with $s^n$ and $s^{n+1/2}$ weights, which relate the energy-weighted spectral sums to the vacuum expectation values of certain commutation relations. After evaluating the commutation relations, the sum rules with $s^n$ weights are reduced to the familiar ones obtained from the operator product expansion (OPE). On the other hand, the sum rules with $s^{n+1/2}$ weights cannot be derived from OPE. They give new relations between the spectral sums and QCD vacuum fluctuations. To derive simple mass formula, we adopt the pole + continuum Ansatz for the spectral function, and solve coupled equations given by the sum rules with $s^{0,1}$ weights and the new sum rule with $s^{1/2}$ weight. Application of our approach to the axial-vector meson is also discussed. |
2007.03857 | Antonio Ortiz | Gyula Benc\'edi, Antonio Ortiz, Sushanta Tripathy | Apparent modification of the jet-like yield in proton-proton collisions
with large underlying event | 6 pages, 4 figures | J. Phys. G: Nucl. Part. Phys. 48 (2021) 015007 | 10.1088/1361-6471/abc5fb | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | This paper presents the production of charged particles associated with
high-$p_{\rm T}$ trigger particles ($8<p_{\rm T}^{\rm trig.}<15$ GeV/$c$) in
proton-proton collisions at $\sqrt{s}=5.02$ TeV simulated with PYTHIA 8.244.
The study is performed as a function of the relative transverse activity
classifier, $R_{\rm T}$, which is the relative charged-particle multiplicity in
the transverse region ($\pi/3<|\phi^{\rm trig.}-\phi^{\rm assoc.}|<2\pi/3$) of
the di-hadron correlations, and it is sensitive to the Multi-Parton
Interactions. The evolution of both the near and the away-side yield of
associated particles ($3\leq p_{\rm T}^{\rm assoc.}< 8$ GeV/$c$) as a function
of $R_{\rm T}$ is investigated. We propose a strategy which allows for the
modelling and subtraction of the underlying event contribution from the near
and the away side in challenging environments like those characterised by large
$R_{\rm T}$. We found that the away-side signal becomes broader with increasing
$R_{\rm T}$, while its corresponding yield is independent of $R_{\rm T}$.
Contrarily, the near-side yield increases with $R_{\rm T}$. This effect is
reminiscent of that seen in heavy-ion collisions, where an enhancement in the
near-side yield for 0-5% central Pb-Pb collisions at $\sqrt{s_{\rm NN}}=2.76$
TeV was reported. A discussion on the origin of these effects in PYTHIA, as
well as their implications for the interpretation of recent LHC results for pp
collisions, is presented.
| [
{
"created": "Wed, 8 Jul 2020 02:24:38 GMT",
"version": "v1"
},
{
"created": "Wed, 9 Dec 2020 14:04:21 GMT",
"version": "v2"
}
] | 2020-12-10 | [
[
"Bencédi",
"Gyula",
""
],
[
"Ortiz",
"Antonio",
""
],
[
"Tripathy",
"Sushanta",
""
]
] | This paper presents the production of charged particles associated with high-$p_{\rm T}$ trigger particles ($8<p_{\rm T}^{\rm trig.}<15$ GeV/$c$) in proton-proton collisions at $\sqrt{s}=5.02$ TeV simulated with PYTHIA 8.244. The study is performed as a function of the relative transverse activity classifier, $R_{\rm T}$, which is the relative charged-particle multiplicity in the transverse region ($\pi/3<|\phi^{\rm trig.}-\phi^{\rm assoc.}|<2\pi/3$) of the di-hadron correlations, and it is sensitive to the Multi-Parton Interactions. The evolution of both the near and the away-side yield of associated particles ($3\leq p_{\rm T}^{\rm assoc.}< 8$ GeV/$c$) as a function of $R_{\rm T}$ is investigated. We propose a strategy which allows for the modelling and subtraction of the underlying event contribution from the near and the away side in challenging environments like those characterised by large $R_{\rm T}$. We found that the away-side signal becomes broader with increasing $R_{\rm T}$, while its corresponding yield is independent of $R_{\rm T}$. Contrarily, the near-side yield increases with $R_{\rm T}$. This effect is reminiscent of that seen in heavy-ion collisions, where an enhancement in the near-side yield for 0-5% central Pb-Pb collisions at $\sqrt{s_{\rm NN}}=2.76$ TeV was reported. A discussion on the origin of these effects in PYTHIA, as well as their implications for the interpretation of recent LHC results for pp collisions, is presented. |
hep-ph/9804427 | Sandip Pakvasa | S. Pakvasa (University of Hawaii at Manoa) | Some Phenomenological Aspects of Neutrino Physics | 8 pages, no figures, Presented at the Pacific Particle Physics
Phenomenology Workshop, APCTP, Seoul, Korea, Nov. 1997. To appear in the
Proceedings | null | null | UH-511-884-98 | hep-ph hep-ex | null | I concentrate on two topics. One is techniques to distinguish amongst various
oscillation scenarios from atmospheric neutrino data; and the other is the
Borexino solar neutrino detector and its capabilities.
| [
{
"created": "Tue, 28 Apr 1998 01:23:31 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Pakvasa",
"S.",
"",
"University of Hawaii at Manoa"
]
] | I concentrate on two topics. One is techniques to distinguish amongst various oscillation scenarios from atmospheric neutrino data; and the other is the Borexino solar neutrino detector and its capabilities. |
hep-ph/9309253 | Ngee-Pong Chang | Ngee-Pong Chang | Braaten-Pisarski Action, Disoriented Chiral Condensate, and Chiral
Symmetry Non-Restoration | (Contributed talk at the 3rd Thermal Fields Workshop held Aug 16 -
27, 1993 at Banff, Canada. ) 6 pages, LaTeX, CCNY-HEP-93-15 | null | null | null | hep-ph | null | The QCD effective action at high T shows a manifest global chiral symmetry.
And calculations show that the order parameter \psibarpsi vanishes above T_c.
It has been popular to refer to this T_c as chiral symmetry restoration
temperature because it fits into our prejudice that chiral symmetry is like an
`ordered' state, and at high T it must become disordered. In fact, NJL ground
state is not an ordered spin state. The recent scenario of a generic class of
disoriented chiral condensate offers an example where \psibarpsi in each little
domain is nonzero, but the average over all space of \psibarpsi vanishes. Such
a dcc ground state continues to break chiral invariance. But how do you
reconcile this with the apparent chiral symmetry at high T? The
Braaten-Pisarski action is a good laboratory to investigate the subtleties of
high temperature chiral symmetry. By carrying out a canonical quantization of
this highly nonlocal action, I demonstrate how the thermal vacuum at high T
conserves the new \beta-chirality but breaks the old T=0 chirality. Lattice
calculations show that the pion develops a screening mass at high T. Our
continuum field theory calculations show that the QCD pion remains massless for
all T. I conclude the talk by showing how the hot pion manages to accomodate
the two results by propagating in the early universe with a halo.
| [
{
"created": "Fri, 10 Sep 1993 12:52:30 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Chang",
"Ngee-Pong",
""
]
] | The QCD effective action at high T shows a manifest global chiral symmetry. And calculations show that the order parameter \psibarpsi vanishes above T_c. It has been popular to refer to this T_c as chiral symmetry restoration temperature because it fits into our prejudice that chiral symmetry is like an `ordered' state, and at high T it must become disordered. In fact, NJL ground state is not an ordered spin state. The recent scenario of a generic class of disoriented chiral condensate offers an example where \psibarpsi in each little domain is nonzero, but the average over all space of \psibarpsi vanishes. Such a dcc ground state continues to break chiral invariance. But how do you reconcile this with the apparent chiral symmetry at high T? The Braaten-Pisarski action is a good laboratory to investigate the subtleties of high temperature chiral symmetry. By carrying out a canonical quantization of this highly nonlocal action, I demonstrate how the thermal vacuum at high T conserves the new \beta-chirality but breaks the old T=0 chirality. Lattice calculations show that the pion develops a screening mass at high T. Our continuum field theory calculations show that the QCD pion remains massless for all T. I conclude the talk by showing how the hot pion manages to accomodate the two results by propagating in the early universe with a halo. |
hep-ph/0506266 | Ting-Wai Chiu | Ting-Wai Chiu, Tung-Han Hsieh, Jon-Yu Lee, Pei-Hua Liu, Hsiu-Ju Chang | Pseudoscalar Decay Constants $ f_{D} $ and $ f_{D_s} $ in Lattice QCD
with Exact Chiral Symmetry | 14 pages, 6 eps figures | Phys.Lett.B624:31-38,2005 | 10.1016/j.physletb.2005.08.009 | NTUTH-05-505C | hep-ph hep-ex hep-lat | null | We determine the masses and decay constants of pseudoscalar mesons $ D $, $
D_s $, and $ K $ in quenched lattice QCD with exact chiral symmetry. For 100
gauge configurations generated with single-plaquette action at $ \beta = 6.1 $
on the $ 20^3 \times 40 $ lattice, we compute point-to-point quark propagators
for 30 quark masses in the range $ 0.03 \le m_q a \le 0.80 $, and measure the
time-correlation functions of pseudoscalar and vector mesons. The inverse
lattice spacing $ a^{-1} $ is determined with the experimental input of $ f_\pi
$, while the strange quark bare mass $ m_s a = 0.08 $, and the charm quark bare
mass $ m_c a = 0.80 $ are fixed such that the masses of the corresponding
vector mesons are in good agreement with $ \phi(1020) $ and $ J/\psi(3097) $
respectively. Our results of pseudoscalar-meson decay constants are $ f_K =
152(6)(10) $ MeV, $ f_D = 235(8)(14)$ MeV, and $ f_{D_s} = 266(10)(18) $ MeV.
| [
{
"created": "Sun, 26 Jun 2005 12:07:04 GMT",
"version": "v1"
}
] | 2011-02-16 | [
[
"Chiu",
"Ting-Wai",
""
],
[
"Hsieh",
"Tung-Han",
""
],
[
"Lee",
"Jon-Yu",
""
],
[
"Liu",
"Pei-Hua",
""
],
[
"Chang",
"Hsiu-Ju",
""
]
] | We determine the masses and decay constants of pseudoscalar mesons $ D $, $ D_s $, and $ K $ in quenched lattice QCD with exact chiral symmetry. For 100 gauge configurations generated with single-plaquette action at $ \beta = 6.1 $ on the $ 20^3 \times 40 $ lattice, we compute point-to-point quark propagators for 30 quark masses in the range $ 0.03 \le m_q a \le 0.80 $, and measure the time-correlation functions of pseudoscalar and vector mesons. The inverse lattice spacing $ a^{-1} $ is determined with the experimental input of $ f_\pi $, while the strange quark bare mass $ m_s a = 0.08 $, and the charm quark bare mass $ m_c a = 0.80 $ are fixed such that the masses of the corresponding vector mesons are in good agreement with $ \phi(1020) $ and $ J/\psi(3097) $ respectively. Our results of pseudoscalar-meson decay constants are $ f_K = 152(6)(10) $ MeV, $ f_D = 235(8)(14)$ MeV, and $ f_{D_s} = 266(10)(18) $ MeV. |
0808.1729 | Ernest Ma | Ernest Ma (UC Riverside) | Dark Scalar Doublets and Neutrino Tribimaximal Mixing from A_4 Symmetry | 8 pages, 2 figures, 1 reference and 1 paragraph added | Phys.Lett.B671:366-368,2009 | 10.1016/j.physletb.2008.12.038 | UCRHEP-T453 (Aug 2008) | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In the context of A_4 symmetry, neutrino tribimaximal mixing is achieved
through the breaking of A_4 to Z_3 (Z_2) in the charged-lepton (neutrino)
sector respectively. The implied vacuum misalignment of the (1,1,1) and (1,0,0)
directions in A_4 space is a difficult technical problem, and cannot be treated
without many auxiliary fields and symmetries (and perhaps extra dimensions). It
is pointed out here that an alternative scenario exists with A_4 alone and no
redundant fields, if neutrino masses are "scotogenic", i.e. radiatively induced
by dark scalar doublets as recently proposed.
| [
{
"created": "Wed, 13 Aug 2008 16:47:07 GMT",
"version": "v1"
},
{
"created": "Mon, 18 Aug 2008 21:56:27 GMT",
"version": "v2"
}
] | 2009-02-02 | [
[
"Ma",
"Ernest",
"",
"UC Riverside"
]
] | In the context of A_4 symmetry, neutrino tribimaximal mixing is achieved through the breaking of A_4 to Z_3 (Z_2) in the charged-lepton (neutrino) sector respectively. The implied vacuum misalignment of the (1,1,1) and (1,0,0) directions in A_4 space is a difficult technical problem, and cannot be treated without many auxiliary fields and symmetries (and perhaps extra dimensions). It is pointed out here that an alternative scenario exists with A_4 alone and no redundant fields, if neutrino masses are "scotogenic", i.e. radiatively induced by dark scalar doublets as recently proposed. |
2406.18673 | Jose Jorge Medina Serna | Alejandro Ayala, Santiago Bernal-Langarica, Jorge Jaber-Urquiza and
Jos\'e Jorge Medina-Serna | Two-gluon one-photon vertex in a magnetic field and its explicit
one-loop approximation in the intermediate field strength regime | Key words: magnetic fields, heavy-ion collisions, photon puzzle,
gluon-photon vertex | null | null | null | hep-ph nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We find the general structure for the two-gluon one-photon vertex in the
presence of a constant magnetic field. We show that, when accounting for the
symmetries satisfied by the strong and electromagnetic interactions under
parity, charge conjugation and gluon interchange, and for gluons and photons on
mass-shell, there exist only three possible tensor structures that span the
vertex. These correspond to external products of the polarization vectors for
each of the particles in the vertex. We also explicitly compute the one-loop
approximation to this vertex in the intermediate field strength regime, which
is the most appropriate one to describe possible effects of the presence of a
magnetic field to enhance photon emission during pre-equilibrium in peripheral
relativistic heavy-ion collisions. We show that the most favored direction for
the photon to propagate is in the plane transverse to the field, which is
consistent with a positive contribution to $\nu_2$ and may help to understand
the larger than expected elliptic flow coefficient measured in this kind of
reactions.
| [
{
"created": "Wed, 26 Jun 2024 18:21:08 GMT",
"version": "v1"
}
] | 2024-06-28 | [
[
"Ayala",
"Alejandro",
""
],
[
"Bernal-Langarica",
"Santiago",
""
],
[
"Jaber-Urquiza",
"Jorge",
""
],
[
"Medina-Serna",
"José Jorge",
""
]
] | We find the general structure for the two-gluon one-photon vertex in the presence of a constant magnetic field. We show that, when accounting for the symmetries satisfied by the strong and electromagnetic interactions under parity, charge conjugation and gluon interchange, and for gluons and photons on mass-shell, there exist only three possible tensor structures that span the vertex. These correspond to external products of the polarization vectors for each of the particles in the vertex. We also explicitly compute the one-loop approximation to this vertex in the intermediate field strength regime, which is the most appropriate one to describe possible effects of the presence of a magnetic field to enhance photon emission during pre-equilibrium in peripheral relativistic heavy-ion collisions. We show that the most favored direction for the photon to propagate is in the plane transverse to the field, which is consistent with a positive contribution to $\nu_2$ and may help to understand the larger than expected elliptic flow coefficient measured in this kind of reactions. |
hep-ph/0202140 | Rudolph C. Hwa | Rudolph C. Hwa and C.B. Yang | Parton Distributions in the Valon Model | 9 pages + 9 figures in eps | Phys.Rev. C66 (2002) 025204 | 10.1103/PhysRevC.66.025204 | OITS-709 | hep-ph | null | The parton distribution functions determined by CTEQ at low $Q^2$ are used as
inputs to test the validity of the valon model. The valon distributions in a
nucleon are first found to be nearly $Q$ independent. The parton distribution
in a valon are shown to be consistent with being universal, independent of the
valon type. The momentum fractions of the partons in the valon add up
separately to one. These properties affirm the validity of the valon model. The
various distributions are parameterized for convenient application of the
model.
| [
{
"created": "Fri, 15 Feb 2002 00:31:57 GMT",
"version": "v1"
}
] | 2009-11-07 | [
[
"Hwa",
"Rudolph C.",
""
],
[
"Yang",
"C. B.",
""
]
] | The parton distribution functions determined by CTEQ at low $Q^2$ are used as inputs to test the validity of the valon model. The valon distributions in a nucleon are first found to be nearly $Q$ independent. The parton distribution in a valon are shown to be consistent with being universal, independent of the valon type. The momentum fractions of the partons in the valon add up separately to one. These properties affirm the validity of the valon model. The various distributions are parameterized for convenient application of the model. |
1208.5301 | Jungil Lee | Geoffrey T. Bodwin (Argonne), U-Rae Kim, Jungil Lee (Korea U.) | Higher-order relativistic corrections to gluon fragmentation into
spin-triplet S-wave quarkonium | 41 pages, 8 figures, 3 tables, minor corrections, version published
in JHEP. Eq. (6.3) corrected. Incorporates erratum JHEP 07 (2023) 170 to JHEP
11 (2012) 020 | JHEP 11 (2012) 020 | 10.1007/JHEP11(2012)020 | ANL-HEP-PR-12-65 | hep-ph | http://creativecommons.org/licenses/by-sa/4.0/ | We compute the relative-order-v^4 contribution to gluon fragmentation into
quarkonium in the 3S1 color-singlet channel, using the nonrelativistic QCD
(NRQCD) factorization approach. The QCD fragmentation process contains infrared
divergences that produce single and double poles in epsilon in 4-2epsilon
dimensions. We devise subtractions that isolate the pole contributions, which
ultimately are absorbed into long-distance NRQCD matrix elements in the NRQCD
matching procedure. The matching procedure involves two-loop renormalizations
of the NRQCD operators. The subtractions are integrated over the phase space
analytically in 4-2epsilon dimensions, and the remainder is integrated over the
phase-space numerically. We find that the order-v^4 contribution is enhanced
relative to the order-v^0 contribution. However, the order-v^4 contribution is
not important numerically at the current level of precision of
quarkonium-hadroproduction phenomenology. We also estimate the contribution to
hadroproduction from gluon fragmentation into quarkonium in the 3PJ color-octet
channel and find that it is significant in comparison to the complete
next-to-leading-order-in-alpha_s contribution in that channel.
| [
{
"created": "Mon, 27 Aug 2012 06:47:34 GMT",
"version": "v1"
},
{
"created": "Fri, 9 Nov 2012 05:19:12 GMT",
"version": "v2"
},
{
"created": "Mon, 24 Jul 2023 07:53:13 GMT",
"version": "v3"
}
] | 2023-07-25 | [
[
"Bodwin",
"Geoffrey T.",
"",
"Argonne"
],
[
"Kim",
"U-Rae",
"",
"Korea U."
],
[
"Lee",
"Jungil",
"",
"Korea U."
]
] | We compute the relative-order-v^4 contribution to gluon fragmentation into quarkonium in the 3S1 color-singlet channel, using the nonrelativistic QCD (NRQCD) factorization approach. The QCD fragmentation process contains infrared divergences that produce single and double poles in epsilon in 4-2epsilon dimensions. We devise subtractions that isolate the pole contributions, which ultimately are absorbed into long-distance NRQCD matrix elements in the NRQCD matching procedure. The matching procedure involves two-loop renormalizations of the NRQCD operators. The subtractions are integrated over the phase space analytically in 4-2epsilon dimensions, and the remainder is integrated over the phase-space numerically. We find that the order-v^4 contribution is enhanced relative to the order-v^0 contribution. However, the order-v^4 contribution is not important numerically at the current level of precision of quarkonium-hadroproduction phenomenology. We also estimate the contribution to hadroproduction from gluon fragmentation into quarkonium in the 3PJ color-octet channel and find that it is significant in comparison to the complete next-to-leading-order-in-alpha_s contribution in that channel. |
hep-ph/0509313 | Thomas Mehen | Sean Fleming (Arizona U.) Thomas Mehen (Duke U. & Jefferson Lab) | Doubly Heavy Baryons, Heavy Quark-DiQuark Symmetry and NRQCD | 23 pages, 7 .ps figures | Phys.Rev.D73:034502,2006 | 10.1103/PhysRevD.73.034502 | null | hep-ph | null | In the heavy quark limit, properties of heavy mesons and doubly heavy baryons
are related by heavy quark-diquark symmetry. This problem is reanalyzed in the
framework of Non-Relativistic QCD (NRQCD). We introduce a novel method for
deriving Potential NRQCD (pNRQCD) Lagrangians for composite fields from vNRQCD,
which contains quarks and antiquarks as explicit degrees of freedom and
maintains manifest power counting in the velocity via a label formalism. A
Hubbard-Stratonovich transformation is used to eliminate four quark
interactions in vNRQCD and then quarks and antiquarks are integrated out to get
effective Lagrangians for composite fields. This method is used to rederive
Lagrangians for the Q\bar Q and QQ sectors of pNRQCD and give a correct
derivation of the O(1/m_Q) prediction for the hyperfine splitting of doubly
heavy baryons.
| [
{
"created": "Tue, 27 Sep 2005 19:39:27 GMT",
"version": "v1"
}
] | 2014-11-18 | [
[
"Fleming",
"Sean",
"",
"Arizona U."
],
[
"Mehen",
"Thomas",
"",
"Duke U. & Jefferson Lab"
]
] | In the heavy quark limit, properties of heavy mesons and doubly heavy baryons are related by heavy quark-diquark symmetry. This problem is reanalyzed in the framework of Non-Relativistic QCD (NRQCD). We introduce a novel method for deriving Potential NRQCD (pNRQCD) Lagrangians for composite fields from vNRQCD, which contains quarks and antiquarks as explicit degrees of freedom and maintains manifest power counting in the velocity via a label formalism. A Hubbard-Stratonovich transformation is used to eliminate four quark interactions in vNRQCD and then quarks and antiquarks are integrated out to get effective Lagrangians for composite fields. This method is used to rederive Lagrangians for the Q\bar Q and QQ sectors of pNRQCD and give a correct derivation of the O(1/m_Q) prediction for the hyperfine splitting of doubly heavy baryons. |
1911.13043 | Marcos Rodriguez Cardoso | M. C. Rodriguez | The Minimal Supersymmetric Standard Model (MSSM) and General Singlet
Extensions of the MSSM (GSEMSSM), a short review | 54 pages, 22 figures, 8 tables. arXiv admin note: text overlap with
arXiv:hep-ph/9903257, arXiv:hep-ph/0606288, arXiv:1205.5081,
arXiv:hep-ph/9611409, arXiv:hep-ph/0012288 by other authors | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this lectures, we give a review about the Minimal Supersymmetric Standard
Model (MSSM) and the General Singlet Extensions of the MSSM (GSEMSSM). We,
first introduce the minimal set of fields to built both models. Then we
introduce their superfields and using them we build the lagrangian of those
models in the superspace formalism. We show how to get the mass spectrum of
those model in the $R$-parity scenarios and we also show how to get some
Feynman Rules with the Gauge Bosons.
| [
{
"created": "Fri, 29 Nov 2019 10:36:53 GMT",
"version": "v1"
}
] | 2019-12-02 | [
[
"Rodriguez",
"M. C.",
""
]
] | In this lectures, we give a review about the Minimal Supersymmetric Standard Model (MSSM) and the General Singlet Extensions of the MSSM (GSEMSSM). We, first introduce the minimal set of fields to built both models. Then we introduce their superfields and using them we build the lagrangian of those models in the superspace formalism. We show how to get the mass spectrum of those model in the $R$-parity scenarios and we also show how to get some Feynman Rules with the Gauge Bosons. |
1504.07966 | Kunio Kaneta | Kunio Kaneta | Probing composite Higgs models by measuring phase shifts at LHC | 4 pages, 5 figures, proceedings of the 2nd Toyama International
Workshop on Higgs as a Probe of New Physics (HPNP 2015), February 11-15, 2015 | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Composite Higgs models are an attractive scenario, where the discovered Higgs
boson is regarded as a Nambu-Goldstone boson associated with spontaneous
breakdown of a global symmetry of more fundamental theory. This class of models
predicts violation of perturbative unitarity at high energies, and new
resonances are expected to appear around TeV scale to maintain the unitarity,
while a sizable phase shift is predicted in certain scattering amplitude. We
investigate the new resonance scale from the phase shift by drawing analogies
with pion physics in QCD. The detectability of the phase shift at LHC and the
ILC is also discussed. This talk was given in {\it HPNP 2015} at University of
Toyama and based on the work in collaboration with S.~Kanemura, T.~Shindou and
N.~Machida (arXiv:1410.8413 [hep-ph]).
| [
{
"created": "Wed, 29 Apr 2015 18:59:53 GMT",
"version": "v1"
}
] | 2015-04-30 | [
[
"Kaneta",
"Kunio",
""
]
] | Composite Higgs models are an attractive scenario, where the discovered Higgs boson is regarded as a Nambu-Goldstone boson associated with spontaneous breakdown of a global symmetry of more fundamental theory. This class of models predicts violation of perturbative unitarity at high energies, and new resonances are expected to appear around TeV scale to maintain the unitarity, while a sizable phase shift is predicted in certain scattering amplitude. We investigate the new resonance scale from the phase shift by drawing analogies with pion physics in QCD. The detectability of the phase shift at LHC and the ILC is also discussed. This talk was given in {\it HPNP 2015} at University of Toyama and based on the work in collaboration with S.~Kanemura, T.~Shindou and N.~Machida (arXiv:1410.8413 [hep-ph]). |
1409.8115 | Diego Cogollo | D. Cogollo | Muon Anomalous Magnetic Moment in a $SU(4) \otimes U(1)_N$ Model | null | International Journal of Modern Physics A Vol. 30 (2015) 1550038 | 10.1142/S0217751X15500384 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study the muon anomalous magnetic moment in an electroweak model based on
the gauge symmetry $SU(4)_L\otimes U(1)_N$, which has right-handed neutrinos in
its spectrum, and no flavor changing neutral currents at tree level. We discuss
relevant collider and electroweak constraints on the model, and derive the most
stringent upper bounds on the scale of symmetry breaking based on the
corrections to the muon magnetic moment. We conclude that a scale of symmetry
breaking of around 2TeV might explain the muon magnetic moment anomaly. In case
the anomaly is otherwise resolved, using the current and projected sensitive of
g-2 experiments, we rule out scales of symmetry breaking smaller than 3.5TeV
(5.5TeV) at $1\sigma$ level.
| [
{
"created": "Mon, 29 Sep 2014 13:29:06 GMT",
"version": "v1"
},
{
"created": "Wed, 1 Oct 2014 16:44:12 GMT",
"version": "v2"
},
{
"created": "Tue, 17 Mar 2015 03:20:01 GMT",
"version": "v3"
}
] | 2015-03-18 | [
[
"Cogollo",
"D.",
""
]
] | We study the muon anomalous magnetic moment in an electroweak model based on the gauge symmetry $SU(4)_L\otimes U(1)_N$, which has right-handed neutrinos in its spectrum, and no flavor changing neutral currents at tree level. We discuss relevant collider and electroweak constraints on the model, and derive the most stringent upper bounds on the scale of symmetry breaking based on the corrections to the muon magnetic moment. We conclude that a scale of symmetry breaking of around 2TeV might explain the muon magnetic moment anomaly. In case the anomaly is otherwise resolved, using the current and projected sensitive of g-2 experiments, we rule out scales of symmetry breaking smaller than 3.5TeV (5.5TeV) at $1\sigma$ level. |
1912.10894 | Valery Lyubovitskij | Thomas Gutsche, Valery E. Lyubovitskij | Strong decays of the hadronic molecule $\Omega^\ast (2012)$ | null | J. Phys. G 48, 025001 (2020) | 10.1088/1361-6471/abcb9f | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Strong two- and three-body decays of the new excited hyperon $\Omega^*(2012)$
are discussed in the hadronic molecular approach. The $\Omega^*(2012)$ state is
considered to contain the mixed $\Xi \bar K$ and $\Omega \eta$ hadronic
components. In our calculations we use a phenomenological hadronic Lagrangian
describing the coupling of the bound states to its constituents and of the
constituents to other hadrons occurring in the final state. Our results show
that the decay widths of the two-body decay modes $\Omega^*(2012) \to \Xi \bar
K$ lie in the few MeV region and are compatible with or dominate over the rates
of the three-body modes $\Omega^*(2012) \to \Xi \pi \bar K$. The sum of two-
and three-body decay widths is consistent with a width of the $\Omega^*(2012)$
originally measured by the Belle Collaboration. A possible scenario for the
suppression of the three-body decay rate recently noticed by the Belle
Collaboration is due to the dominant admixture of the $\Omega \eta$ hadronic
component in the $\Omega^*(2012)$ state.
| [
{
"created": "Mon, 23 Dec 2019 14:55:08 GMT",
"version": "v1"
},
{
"created": "Wed, 23 Dec 2020 08:05:05 GMT",
"version": "v2"
}
] | 2020-12-24 | [
[
"Gutsche",
"Thomas",
""
],
[
"Lyubovitskij",
"Valery E.",
""
]
] | Strong two- and three-body decays of the new excited hyperon $\Omega^*(2012)$ are discussed in the hadronic molecular approach. The $\Omega^*(2012)$ state is considered to contain the mixed $\Xi \bar K$ and $\Omega \eta$ hadronic components. In our calculations we use a phenomenological hadronic Lagrangian describing the coupling of the bound states to its constituents and of the constituents to other hadrons occurring in the final state. Our results show that the decay widths of the two-body decay modes $\Omega^*(2012) \to \Xi \bar K$ lie in the few MeV region and are compatible with or dominate over the rates of the three-body modes $\Omega^*(2012) \to \Xi \pi \bar K$. The sum of two- and three-body decay widths is consistent with a width of the $\Omega^*(2012)$ originally measured by the Belle Collaboration. A possible scenario for the suppression of the three-body decay rate recently noticed by the Belle Collaboration is due to the dominant admixture of the $\Omega \eta$ hadronic component in the $\Omega^*(2012)$ state. |
hep-ph/0608287 | Z. Merebashvili | J. G. Korner, Z. Merebashvili, and M. Rogal | Next-to-next-to-leading order ${\cal O}(\alpha^2\alpha_s^2)$ results for
top quark pair production in photon--photon collisions: The one-loop squared
contributions | 11 pages, Revtex, slight change in title and abstract, one paragraph
and reference added, matches published version | Phys.Rev.D74:094006,2006 | 10.1103/PhysRevD.74.094006 | null | hep-ph | null | We calculate the one-loop squared contributions to the
next-to-next-to-leading order ${\cal O}(\alpha^2\alpha_s^2)$ radiative QCD
corrections for the production of heavy quark pairs in the collisions of
unpolarized on--shell photons. In particular, we present analytical results for
the squared matrix elements that correspond to the product of the one--loop
amplitudes. All results of the perturbative calculation are given in the
dimensional regularization scheme. These results represent the Abelian part of
the corresponding gluon--induced next-to-next-to-leading order cross section
for heavy quark pair hadroproduction.
| [
{
"created": "Sat, 26 Aug 2006 14:14:42 GMT",
"version": "v1"
},
{
"created": "Sat, 4 Nov 2006 07:35:15 GMT",
"version": "v2"
}
] | 2008-11-26 | [
[
"Korner",
"J. G.",
""
],
[
"Merebashvili",
"Z.",
""
],
[
"Rogal",
"M.",
""
]
] | We calculate the one-loop squared contributions to the next-to-next-to-leading order ${\cal O}(\alpha^2\alpha_s^2)$ radiative QCD corrections for the production of heavy quark pairs in the collisions of unpolarized on--shell photons. In particular, we present analytical results for the squared matrix elements that correspond to the product of the one--loop amplitudes. All results of the perturbative calculation are given in the dimensional regularization scheme. These results represent the Abelian part of the corresponding gluon--induced next-to-next-to-leading order cross section for heavy quark pair hadroproduction. |
hep-ph/0309324 | Felipe J. Llanes-Estrada | Antonio Dobado and Felipe J. Llanes-Estrada | The Viscosity of Meson Matter | null | Phys.Rev. D69 (2004) 116004 | 10.1103/PhysRevD.69.116004 | null | hep-ph | null | We report a calculation of the shear viscosity in a relativistic
multicomponent meson gas as a function of temperature and chemical potentials.
We approximately solve the Uehling-Uhlenbeck transport equation of kinetic
theory, appropriate for a boson gas, with relativistic kinematics. Since at low
temperatures the gas can be taken as mostly composed of pions, with a fraction
of kaons and etas, we explore the region where binary elastic collisions with
at least one pion are the dominant scattering processes. Our input meson
scattering phase shifts are fits to the experimental data obtained from chiral
perturbation theory and the Inverse Amplitude Method. Our results take the
correct non-relativistic limit (viscosity proportional to the square root of
the temperature), show a viscosity of order the cubed of the pion mass up to
temperatures somewhat below that mass, and then a large increase due to kaons
and etas. Our approximation may break down at even higher temperatures, where
the viscosity follows a temperature power law with an exponent near 3.
| [
{
"created": "Mon, 29 Sep 2003 16:14:15 GMT",
"version": "v1"
}
] | 2009-11-10 | [
[
"Dobado",
"Antonio",
""
],
[
"Llanes-Estrada",
"Felipe J.",
""
]
] | We report a calculation of the shear viscosity in a relativistic multicomponent meson gas as a function of temperature and chemical potentials. We approximately solve the Uehling-Uhlenbeck transport equation of kinetic theory, appropriate for a boson gas, with relativistic kinematics. Since at low temperatures the gas can be taken as mostly composed of pions, with a fraction of kaons and etas, we explore the region where binary elastic collisions with at least one pion are the dominant scattering processes. Our input meson scattering phase shifts are fits to the experimental data obtained from chiral perturbation theory and the Inverse Amplitude Method. Our results take the correct non-relativistic limit (viscosity proportional to the square root of the temperature), show a viscosity of order the cubed of the pion mass up to temperatures somewhat below that mass, and then a large increase due to kaons and etas. Our approximation may break down at even higher temperatures, where the viscosity follows a temperature power law with an exponent near 3. |
hep-ph/9206254 | Stephen Naculich | S. G. Naculich and C.-P. Yuan | Can the Electroweak Symmetry-breaking Sector Be Hidden? | 10 pages, phyzzx, JHU-TIPAC-920017 | Phys.Lett.B293:395-399,1992 | 10.1016/0370-2693(92)90902-G | null | hep-ph | null | In a recent paper, Chivukula and Golden claimed that the electroweak
symmetry--breaking sector could be hidden if there were many inelastic channels
in the longitudinal $WW$ scattering process. They presented a model in which
the $W$'s couple to pseudo--Goldstone bosons, which may be difficult to detect
experimentally. Because of these inelastic channels, the $WW$ interactions do
not become strong in the TeV region. We demonstrate that, despite the reduced
$WW$ elastic amplitudes in this model, the total event rate ($\sim 5000$ extra
longitudinal $W^+W^-$ pairs produced in one standard SSC year) does not
decrease with an increasing number of inelastic channels, and is roughly the
same as in a model with a broad high--energy resonance and no inelastic
channels.
| [
{
"created": "Fri, 26 Jun 1992 17:29:00 GMT",
"version": "v1"
}
] | 2008-11-26 | [
[
"Naculich",
"S. G.",
""
],
[
"Yuan",
"C. -P.",
""
]
] | In a recent paper, Chivukula and Golden claimed that the electroweak symmetry--breaking sector could be hidden if there were many inelastic channels in the longitudinal $WW$ scattering process. They presented a model in which the $W$'s couple to pseudo--Goldstone bosons, which may be difficult to detect experimentally. Because of these inelastic channels, the $WW$ interactions do not become strong in the TeV region. We demonstrate that, despite the reduced $WW$ elastic amplitudes in this model, the total event rate ($\sim 5000$ extra longitudinal $W^+W^-$ pairs produced in one standard SSC year) does not decrease with an increasing number of inelastic channels, and is roughly the same as in a model with a broad high--energy resonance and no inelastic channels. |
1811.12302 | Andreas Schmitt | Alexander Haber and Andreas Schmitt | Multi-winding flux tubes in CFL quark matter | 12 pages, 3 figures, proceedings contribution to "XIIIth Quark
Confinement and the Hadron Spectrum", 31 July - 6 August 2018, Maynooth
University, Ireland | null | null | null | hep-ph astro-ph.HE nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Color-flavor locked quark matter can be described as a three-component
superconductor and thus shows unconventional behavior in the transition regime
from type-I to type-II superconductivity. We discuss this behavior by studying
magnetic line defects in a Ginzburg-Landau approach, taking into account all
possible values of the three winding numbers. After a brief discussion of the
defects that include baryon circulation we focus on pure magnetic flux tubes.
We show that at strong coupling, relevant for neutron stars, type-II behavior
is conceivable and the most preferred configuration has minimal total winding.
Only at weak coupling we find a regime where multi-winding flux tubes are
preferred, although this regime most likely requires an unrealistically large
superconducting gap.
| [
{
"created": "Thu, 29 Nov 2018 16:51:59 GMT",
"version": "v1"
}
] | 2018-11-30 | [
[
"Haber",
"Alexander",
""
],
[
"Schmitt",
"Andreas",
""
]
] | Color-flavor locked quark matter can be described as a three-component superconductor and thus shows unconventional behavior in the transition regime from type-I to type-II superconductivity. We discuss this behavior by studying magnetic line defects in a Ginzburg-Landau approach, taking into account all possible values of the three winding numbers. After a brief discussion of the defects that include baryon circulation we focus on pure magnetic flux tubes. We show that at strong coupling, relevant for neutron stars, type-II behavior is conceivable and the most preferred configuration has minimal total winding. Only at weak coupling we find a regime where multi-winding flux tubes are preferred, although this regime most likely requires an unrealistically large superconducting gap. |
1207.6968 | Jordy Vries de | J. de Vries | Parity- and Time-Reversal-Violating Moments of Light Nuclei | 8 pages, contribution to the proceedings of the 5th International
Symposium on Symmetries in Subatomic Physics (SSP2012), June 18-22, 2012,
Groningen, The Netherlands | Hyperfine Interact. 214, 79-86, 2013 | 10.1007/s10751-013-0807-8 | null | hep-ph nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | I present the calculation of parity- and time-reversal-violating moments of
the nucleon and light nuclei, originating from the QCD theta term and effective
dimension-six operators. By applying chiral effective field theory these
calculations are performed in a unified framework. I argue that measurements of
a few light-nuclear electric dipole moments would shed light on the mechanism
of parity and time-reversal violation.
| [
{
"created": "Mon, 30 Jul 2012 15:30:56 GMT",
"version": "v1"
},
{
"created": "Tue, 31 Jul 2012 08:32:59 GMT",
"version": "v2"
},
{
"created": "Mon, 25 Mar 2013 08:18:40 GMT",
"version": "v3"
}
] | 2013-03-26 | [
[
"de Vries",
"J.",
""
]
] | I present the calculation of parity- and time-reversal-violating moments of the nucleon and light nuclei, originating from the QCD theta term and effective dimension-six operators. By applying chiral effective field theory these calculations are performed in a unified framework. I argue that measurements of a few light-nuclear electric dipole moments would shed light on the mechanism of parity and time-reversal violation. |
hep-ph/0206120 | Sergio Daniel Grillo | S. Grillo and H. Montani | Integrable mixing of A_{n-1} type vertex models | REVTeX 28 pages. Here we complete the proof of integrability for
mixed vertex models as defined in the first version | J.Math.Phys. 45 (2004) 2073-2089 | 10.1063/1.1704846 | null | hep-ph hep-th | null | Given a family of monodromy matrices {T_u; u=0,1,...,K-1} corresponding to
integrable anisotropic vertex models of A_{(n_u)-1}-type, we build up a related
mixed vertex model by means of glueing the lattices on which they are defined,
in such a way that integrability property is preserved. Algebraically, the
glueing process is implemented through one dimensional representations of
rectangular matrix algebras A(R_p,R_q), namely, the `glueing matrices' zeta_u.
Here R_n indicates the Yang-Baxter operator associated to the standard Hopf
algebra deformation of the simple Lie algebra A_{n-1}. We show there exists a
pseudovacuum subspace with respect to which algebraic Bethe ansatz can be
applied. For each pseudovacuum vector we have a set of nested Bethe ansatz
equations identical to the ones corresponding to an A_{m-1} quasi-periodic
model, with m equal to the minimal range of involved glueing matrices.
| [
{
"created": "Thu, 13 Jun 2002 17:34:08 GMT",
"version": "v1"
},
{
"created": "Fri, 30 Aug 2002 21:24:10 GMT",
"version": "v2"
},
{
"created": "Fri, 15 Nov 2002 14:24:46 GMT",
"version": "v3"
}
] | 2009-11-07 | [
[
"Grillo",
"S.",
""
],
[
"Montani",
"H.",
""
]
] | Given a family of monodromy matrices {T_u; u=0,1,...,K-1} corresponding to integrable anisotropic vertex models of A_{(n_u)-1}-type, we build up a related mixed vertex model by means of glueing the lattices on which they are defined, in such a way that integrability property is preserved. Algebraically, the glueing process is implemented through one dimensional representations of rectangular matrix algebras A(R_p,R_q), namely, the `glueing matrices' zeta_u. Here R_n indicates the Yang-Baxter operator associated to the standard Hopf algebra deformation of the simple Lie algebra A_{n-1}. We show there exists a pseudovacuum subspace with respect to which algebraic Bethe ansatz can be applied. For each pseudovacuum vector we have a set of nested Bethe ansatz equations identical to the ones corresponding to an A_{m-1} quasi-periodic model, with m equal to the minimal range of involved glueing matrices. |
1512.08443 | Matthias Berwein | Matthias Berwein, Nora Brambilla, Peter Petreczky, Antonio Vairo | The Polyakov loop at next-to-next-to leading order | 65 pages, 13 figures | Phys. Rev. D 93, 034010 (2016) | 10.1103/PhysRevD.93.034010 | TUM-EFT 67/15 | hep-ph hep-lat hep-th nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We calculate the next-to-next-to-leading correction to the expectation value
of the Polyakov loop or equivalently to the free energy of a static charge.
This correction is of order $g^5$. We show that up to this order the free
energy of the static charge is proportional to the quadratic Casimir operator
of the corresponding representation. We also compare our perturbative result
with the most recent lattice results in SU(3) gauge theory.
| [
{
"created": "Mon, 28 Dec 2015 16:20:33 GMT",
"version": "v1"
},
{
"created": "Wed, 30 Dec 2015 15:13:39 GMT",
"version": "v2"
}
] | 2016-02-17 | [
[
"Berwein",
"Matthias",
""
],
[
"Brambilla",
"Nora",
""
],
[
"Petreczky",
"Peter",
""
],
[
"Vairo",
"Antonio",
""
]
] | We calculate the next-to-next-to-leading correction to the expectation value of the Polyakov loop or equivalently to the free energy of a static charge. This correction is of order $g^5$. We show that up to this order the free energy of the static charge is proportional to the quadratic Casimir operator of the corresponding representation. We also compare our perturbative result with the most recent lattice results in SU(3) gauge theory. |
hep-ph/9603443 | Antonio Lanza | E.Kh. Akhmedov, A. Lanza, S.T. Petcov and D.W. Sciama | Resonant neutrino spin-flavor precession and supernova shock revival | 16 pages, latex, 2 figures. added few references | Phys.Rev.D55:515-522,1997 | 10.1103/PhysRevD.55.515 | SISSA 40/96/A-EP, TUM-HEP-239/96, SFB-375/83 | hep-ph astro-ph | null | A new mechanism of supernova shock revival is proposed, which involves
resonant spin--flavor precession of neutrinos with a transition magnetic moment
in the magnetic field of the supernova. The mechanism can be operative in
supernovae for transition magnetic moments as small as $10^{-14}\mu_B$ provided
the neutrino mass squared difference is in the range $\Delta m^2 \sim (3 \;{\rm
eV})^2-(600 \;{\rm eV})^2$. It is shown that this mechanism can increase the
neutrino--induced shock reheating energy by about 60\%.
| [
{
"created": "Sat, 30 Mar 1996 11:11:52 GMT",
"version": "v1"
},
{
"created": "Tue, 16 Apr 1996 13:26:06 GMT",
"version": "v2"
}
] | 2008-11-26 | [
[
"Akhmedov",
"E. Kh.",
""
],
[
"Lanza",
"A.",
""
],
[
"Petcov",
"S. T.",
""
],
[
"Sciama",
"D. W.",
""
]
] | A new mechanism of supernova shock revival is proposed, which involves resonant spin--flavor precession of neutrinos with a transition magnetic moment in the magnetic field of the supernova. The mechanism can be operative in supernovae for transition magnetic moments as small as $10^{-14}\mu_B$ provided the neutrino mass squared difference is in the range $\Delta m^2 \sim (3 \;{\rm eV})^2-(600 \;{\rm eV})^2$. It is shown that this mechanism can increase the neutrino--induced shock reheating energy by about 60\%. |
hep-ph/9805479 | Elisabetta Sassaroli | E. Sassaroli, Y. N. Srivastava, J. Swain, and A. Widom | The Dynamical and Static Casimir Effects and the Thermodynamic
Instability | 12 pages, Tex file, no figures. Talk presented by E. Sassaroli at the
Casimir effect topical group meeting ITAMP, Smithsonian-Harvard Center for
Astrophysics, March 1998 | null | null | null | hep-ph | null | The dynamical Casimir effect for the ideal case of two perfectly conducting
non-charged parallel plates, is discussed using the zero-point energy summation
method to the first order in perturbation theory. We show that it is possible
to create photon radiation when the two plates are modulated rapidly in time.
Moreover we point out that the static Casimir energy between two conducting
non-charged parallel plates violates the thermodynamic stability condition
normally associated with the second law of thermodynamics.
| [
{
"created": "Wed, 27 May 1998 14:57:17 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Sassaroli",
"E.",
""
],
[
"Srivastava",
"Y. N.",
""
],
[
"Swain",
"J.",
""
],
[
"Widom",
"A.",
""
]
] | The dynamical Casimir effect for the ideal case of two perfectly conducting non-charged parallel plates, is discussed using the zero-point energy summation method to the first order in perturbation theory. We show that it is possible to create photon radiation when the two plates are modulated rapidly in time. Moreover we point out that the static Casimir energy between two conducting non-charged parallel plates violates the thermodynamic stability condition normally associated with the second law of thermodynamics. |
1711.10831 | Nasuf Sonmez PhD | Nasuf Sonmez | Production of neutral Higgs bosons associated with Z-boson and photon in
2HDM at future lepton colliders | 10 pages, 6 figures | null | null | 17-FEN-054 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Inspired by precision tests of the Standard Model in future lepton colliders,
the numerical analysis of the following scattering processes, $e^+e^-
\rightarrow Z h^0\gamma$ and $e^+e^- \rightarrow Z H^0 \gamma$, are carried at
the tree level including all possible diagrams in the two-Higgs-doublet model
(2HDM). This model has many free parameters, but the parameters which take part
in the scattering amplitudes of these two processes are primarily the mixing
angle parameter, $s_{\beta-\alpha}$, and the masses of the neutral Higgs
bosons, ($h^0, H^0$). Therefore, measuring the production rates of $Z
h^0\gamma$ and $Z H^0 \gamma$ final states open another test for the scalar
sectors of the 2HDM. The numerical analysis is performed under the current
experimental constraints. The production rates and the asymmetry in the
forward-backward direction are presented as a function of the center-of-mass
energy covering the future lepton colliders. The unpolarized cross-section gets
up to 6.19 (4.86) fb at $\sqrt{s} = 350$ (500) GeV and 0.164 (0.157) fb at
$\sqrt{s} = 350$ (500) GeV for $e^+e^- \rightarrow Z h^0\gamma$ and $e^+e^-
\rightarrow Z H^0 \gamma$, respectively. The polarization of the incoming
$e^+e^-$ beams are studied for various configurations, and it enhances the
cross-section by a factor of 1.78 in both processes for
$P_{e^+,e^-}=(+0.6,-0.8)$.
| [
{
"created": "Wed, 29 Nov 2017 13:08:55 GMT",
"version": "v1"
},
{
"created": "Thu, 24 Jan 2019 13:58:24 GMT",
"version": "v2"
},
{
"created": "Thu, 31 Jan 2019 13:09:47 GMT",
"version": "v3"
},
{
"created": "Wed, 20 Feb 2019 12:33:20 GMT",
"version": "v4"
},
{
"c... | 2019-06-21 | [
[
"Sonmez",
"Nasuf",
""
]
] | Inspired by precision tests of the Standard Model in future lepton colliders, the numerical analysis of the following scattering processes, $e^+e^- \rightarrow Z h^0\gamma$ and $e^+e^- \rightarrow Z H^0 \gamma$, are carried at the tree level including all possible diagrams in the two-Higgs-doublet model (2HDM). This model has many free parameters, but the parameters which take part in the scattering amplitudes of these two processes are primarily the mixing angle parameter, $s_{\beta-\alpha}$, and the masses of the neutral Higgs bosons, ($h^0, H^0$). Therefore, measuring the production rates of $Z h^0\gamma$ and $Z H^0 \gamma$ final states open another test for the scalar sectors of the 2HDM. The numerical analysis is performed under the current experimental constraints. The production rates and the asymmetry in the forward-backward direction are presented as a function of the center-of-mass energy covering the future lepton colliders. The unpolarized cross-section gets up to 6.19 (4.86) fb at $\sqrt{s} = 350$ (500) GeV and 0.164 (0.157) fb at $\sqrt{s} = 350$ (500) GeV for $e^+e^- \rightarrow Z h^0\gamma$ and $e^+e^- \rightarrow Z H^0 \gamma$, respectively. The polarization of the incoming $e^+e^-$ beams are studied for various configurations, and it enhances the cross-section by a factor of 1.78 in both processes for $P_{e^+,e^-}=(+0.6,-0.8)$. |
hep-ph/9511389 | Erhan Iltan | T. M. Aliev, D. A. Demir, E. Iltan, N. K. Pak | Single Leptoquark Production at TeV Energy $\gamma p$ Colliders | 14 pages, 4 figures, LaTeX formatted | null | 10.1103/PhysRevD.54.4263 | METU-PHYS-HEP-95-14, ICTP REPORT-95 | hep-ph | null | The resolved and direct photon contributions to the single leptoquark (L)
production process $\gamma p\rightarrow L e$ are analysed for both scalar (S)
and vector (V) leptoquarks in detail. It is shown that resolved photon
contribution dominates for $M_{L}\leq 300 GeV$. For $M_{V}\geq 1 TeV$ and
$M_{S}\geq 0.5 TeV$ cross section is completely determined by the direct photon
conribution. The vector leptoquarks are discussed for both gauge- and non-gauge
cases seperately.
| [
{
"created": "Wed, 22 Nov 1995 09:48:07 GMT",
"version": "v1"
},
{
"created": "Tue, 28 Nov 1995 11:27:01 GMT",
"version": "v2"
}
] | 2009-10-28 | [
[
"Aliev",
"T. M.",
""
],
[
"Demir",
"D. A.",
""
],
[
"Iltan",
"E.",
""
],
[
"Pak",
"N. K.",
""
]
] | The resolved and direct photon contributions to the single leptoquark (L) production process $\gamma p\rightarrow L e$ are analysed for both scalar (S) and vector (V) leptoquarks in detail. It is shown that resolved photon contribution dominates for $M_{L}\leq 300 GeV$. For $M_{V}\geq 1 TeV$ and $M_{S}\geq 0.5 TeV$ cross section is completely determined by the direct photon conribution. The vector leptoquarks are discussed for both gauge- and non-gauge cases seperately. |
hep-ph/0404189 | Vladimir Sauli | V. Sauli | Solving the Bethe-Salpeter equation for fermion-antifermion pseudoscalar
bound state in Minkowski space | 19 pages, 1 figure | null | null | null | hep-ph | null | The new method of solution of the Bethe-Salpeter equation for quark-antiquark
pseudoscalar bound state is proposed. With the help of integral representation
the results are directly obtained in Minkowski space. Dressing of Greens
functions is naturally considered providing thus the correct inclusion of the
running coupling constant and the quark propagators as well as. The first
numerical results are presented for a simplified ladder approximation.
| [
{
"created": "Thu, 22 Apr 2004 06:59:12 GMT",
"version": "v1"
},
{
"created": "Thu, 22 Feb 2007 16:48:44 GMT",
"version": "v2"
}
] | 2007-05-23 | [
[
"Sauli",
"V.",
""
]
] | The new method of solution of the Bethe-Salpeter equation for quark-antiquark pseudoscalar bound state is proposed. With the help of integral representation the results are directly obtained in Minkowski space. Dressing of Greens functions is naturally considered providing thus the correct inclusion of the running coupling constant and the quark propagators as well as. The first numerical results are presented for a simplified ladder approximation. |
2007.15016 | Matthew Kirk | Joe Davighi, Matthew Kirk, Marco Nardecchia | Anomalies and accidental symmetries: charging the scalar leptoquark
under $L_\mu$-$L_\tau$ | 32 pages, 6 figures. v2: journal version - corrected diagrams in fig
6, improved discussion of baryon number violation and added brief discussion
of neutrino mass generation, references added | JHEP 12 (2020) 111 | 10.1007/JHEP12(2020)111 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | While the $S_3$ scalar leptoquark presents a possible tree-level explanation
of the $b \to s \ell \ell$ flavour anomalies, it suffers from two conceptual
problems which are often disregarded by model-builders. Firstly, the quantum
numbers of the $S_3$ allow for a renormalisable diquark operator that would
trigger rapid proton decay unless its coupling were tuned away. Secondly, one
expects the leptoquark to have generic couplings to leptons, which require
tuning to avoid stringent experimental bounds on lepton flavour violation. By
gauging a $U(1)$ current that acts as $L_\mu - L_\tau$ on the Standard Model
(SM) fermions, and under which the leptoquark has charge $-1$, one can remedy
both these problems. The additional $U(1)$, which is spontaneously broken at
some high scale, is associated with a massive $Z^\prime$ gauge boson and a
scalar SM singlet $\Phi$, which play no direct role in mediating the anomalous
$B$ meson decays. By computing one- and two-loop mass corrections, we show that
this pair of particles can be hidden away at much higher mass scales without
destabilising either the Higgs or the leptoquark masses. The only low-energy
relic of gauging $L_\mu - L_\tau$ is thus the accidental global symmetry
structure of the lagrangian. On the other hand, we find quite generally that an
$S_3$ leptoquark that mediates the $b \to s \ell \ell$ anomalies cannot be much
heavier than a few TeV without itself inducing large Higgs mass corrections.
| [
{
"created": "Wed, 29 Jul 2020 18:00:03 GMT",
"version": "v1"
},
{
"created": "Mon, 4 Jan 2021 11:47:57 GMT",
"version": "v2"
}
] | 2021-01-05 | [
[
"Davighi",
"Joe",
""
],
[
"Kirk",
"Matthew",
""
],
[
"Nardecchia",
"Marco",
""
]
] | While the $S_3$ scalar leptoquark presents a possible tree-level explanation of the $b \to s \ell \ell$ flavour anomalies, it suffers from two conceptual problems which are often disregarded by model-builders. Firstly, the quantum numbers of the $S_3$ allow for a renormalisable diquark operator that would trigger rapid proton decay unless its coupling were tuned away. Secondly, one expects the leptoquark to have generic couplings to leptons, which require tuning to avoid stringent experimental bounds on lepton flavour violation. By gauging a $U(1)$ current that acts as $L_\mu - L_\tau$ on the Standard Model (SM) fermions, and under which the leptoquark has charge $-1$, one can remedy both these problems. The additional $U(1)$, which is spontaneously broken at some high scale, is associated with a massive $Z^\prime$ gauge boson and a scalar SM singlet $\Phi$, which play no direct role in mediating the anomalous $B$ meson decays. By computing one- and two-loop mass corrections, we show that this pair of particles can be hidden away at much higher mass scales without destabilising either the Higgs or the leptoquark masses. The only low-energy relic of gauging $L_\mu - L_\tau$ is thus the accidental global symmetry structure of the lagrangian. On the other hand, we find quite generally that an $S_3$ leptoquark that mediates the $b \to s \ell \ell$ anomalies cannot be much heavier than a few TeV without itself inducing large Higgs mass corrections. |
1808.06517 | Jiro Hashiba Ph.D. | Jiro Hashiba | Dark Energy from Eternal Pair-production of Fermions | 9 pages, 4 figures; v4: section II significantly revised, section VI
added, and minor corrections | null | null | null | hep-ph gr-qc hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study a toy model in which Majorana or Dirac fermions behave as the source
for a small vacuum energy in the present Universe. In the model, a
self-interacting scalar boson coupled with fermions induces attractive and
repulsive interactions between the fermions simultaneously. These interactions
allow for the existence of a metastable state with positive energy density
comprised of fermions degenerate inside a Fermi surface. The energy density of
the metastable state remains constant as the Universe expands. This is because
pair-productions of fermions from the vacuum continuously take place at no
energy cost and keep supplying fermions uniformly to the Universe. The observed
vacuum energy density $\sim 10^{-47}~\textrm{GeV}^4$ is reproduced for the
fermion and scalar mass of the order $10^{-3}~\textrm{eV}$.
| [
{
"created": "Mon, 20 Aug 2018 15:36:31 GMT",
"version": "v1"
},
{
"created": "Mon, 17 Sep 2018 13:33:17 GMT",
"version": "v2"
},
{
"created": "Mon, 29 Oct 2018 13:21:10 GMT",
"version": "v3"
},
{
"created": "Mon, 7 Jan 2019 15:27:51 GMT",
"version": "v4"
}
] | 2019-01-08 | [
[
"Hashiba",
"Jiro",
""
]
] | We study a toy model in which Majorana or Dirac fermions behave as the source for a small vacuum energy in the present Universe. In the model, a self-interacting scalar boson coupled with fermions induces attractive and repulsive interactions between the fermions simultaneously. These interactions allow for the existence of a metastable state with positive energy density comprised of fermions degenerate inside a Fermi surface. The energy density of the metastable state remains constant as the Universe expands. This is because pair-productions of fermions from the vacuum continuously take place at no energy cost and keep supplying fermions uniformly to the Universe. The observed vacuum energy density $\sim 10^{-47}~\textrm{GeV}^4$ is reproduced for the fermion and scalar mass of the order $10^{-3}~\textrm{eV}$. |
hep-ph/0409080 | Alexander Khodjamirian | Christine Bruch, Alexander Khodjamirian, Johann H.Kuhn | Modeling the Pion and Kaon Form Factors in the Timelike Region | 31 pages, 7 figures,latex, one reference changed, version to appear
in Eur.Phys.J C | Eur.Phys.J. C39 (2005) 41-54 | 10.1140/epjc/s2004-02064-3 | TTP04-20, SI-HEP-2004-09 | hep-ph | null | New, accurate measurements of the pion and kaon electromagnetic form factors
are expected in the near future from experiments at electron-positron
colliders,using the radiative return method. We construct a model for the
timelike pion electromagnetic form factor, that is valid also at momentum
transfers far above the $\rho$ resonance. The ansatz is based on vector
dominance and includes a pattern of radial excitations expected from dual
resonance models.The form factor is fitted to the existing data in the timelike
region, continued to the spacelike region and compared with the measurements
there and with the QCD predictions. Furthermore, the model is extended to the
kaon electromagnetic form factor. Using isospin and SU(3)-flavour symmetry
relations we extract the isospin-one contribution and predict the kaon weak
form factor accessible in semileptonic $\tau$ decays.
| [
{
"created": "Tue, 7 Sep 2004 18:49:41 GMT",
"version": "v1"
},
{
"created": "Sat, 18 Dec 2004 16:25:20 GMT",
"version": "v2"
}
] | 2015-06-25 | [
[
"Bruch",
"Christine",
""
],
[
"Khodjamirian",
"Alexander",
""
],
[
"Kuhn",
"Johann H.",
""
]
] | New, accurate measurements of the pion and kaon electromagnetic form factors are expected in the near future from experiments at electron-positron colliders,using the radiative return method. We construct a model for the timelike pion electromagnetic form factor, that is valid also at momentum transfers far above the $\rho$ resonance. The ansatz is based on vector dominance and includes a pattern of radial excitations expected from dual resonance models.The form factor is fitted to the existing data in the timelike region, continued to the spacelike region and compared with the measurements there and with the QCD predictions. Furthermore, the model is extended to the kaon electromagnetic form factor. Using isospin and SU(3)-flavour symmetry relations we extract the isospin-one contribution and predict the kaon weak form factor accessible in semileptonic $\tau$ decays. |
1806.06997 | Genaro Toledo | J. E. Chavez-Saab and Genaro Toledo | Closing the Gap on $R_{D^*}$ by including longitudinal effects | Table 1 updated. After publication we found a bug in the
transcription code for the numerical integration. Using the corrected values,
the results on $R_{D\pi}$ are consistent with $R_{D^*}$ at the current
precision. This modifies our previous finding that lead us to a different
conclusion | Phys. Rev. D 98, 056014 (2018) | 10.1103/PhysRevD.98.056014 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Measurements of the $R_{D^*}\equiv\mathrm{Br}(B\rightarrow \tau\nu
D^*)/\mathrm{Br}(B\rightarrow e\nu D^*)$ parameter remain in tension with the
standard model prediction, despite recent results helping to close the gap. The
standard model prediction it is compared with considers the $D^*$ as an
external particle, even though what is detected in experiments is a $D\pi$ pair
it decays into, from which it is reconstructed. We argue that the experimental
result must be compared with the theoretical prediction considering the full
4-body decay $(B\rightarrow l\nu D^* \to l\nu D\pi)$. We show that the
longitudinal degree of freedom of the off-shell $D^*$ helps to further close
the disagreement gap with experimental data. We find values for the ratio
$R_{D\pi}^l \equiv {\mathrm{Br}(B\rightarrow \tau\nu_\tau D
\pi)}/\mathrm{Br}(B\rightarrow l\nu_l D\pi)$ of $R_{D\pi}^e=0.274\pm0.003$ and
$R_{D\pi}^\mu=0.275\pm0.003$, where the uncertainty comes from the uncertainty
of the form factors parameters. Comparing against $R_{D\pi}$ reduces the gap
with the latest LHCb result from $1.1\sigma$ to $0.48\sigma$, while the gap
with the latest Belle result is reduced from $0.42\sigma$ to just $0.10\sigma$
and with the world average results from $3.7\sigma$ to $2.1\sigma$. Erratum
added at the end of the file.
| [
{
"created": "Tue, 19 Jun 2018 01:24:11 GMT",
"version": "v1"
},
{
"created": "Tue, 11 Sep 2018 22:36:44 GMT",
"version": "v2"
},
{
"created": "Wed, 8 May 2019 23:16:04 GMT",
"version": "v3"
}
] | 2019-05-10 | [
[
"Chavez-Saab",
"J. E.",
""
],
[
"Toledo",
"Genaro",
""
]
] | Measurements of the $R_{D^*}\equiv\mathrm{Br}(B\rightarrow \tau\nu D^*)/\mathrm{Br}(B\rightarrow e\nu D^*)$ parameter remain in tension with the standard model prediction, despite recent results helping to close the gap. The standard model prediction it is compared with considers the $D^*$ as an external particle, even though what is detected in experiments is a $D\pi$ pair it decays into, from which it is reconstructed. We argue that the experimental result must be compared with the theoretical prediction considering the full 4-body decay $(B\rightarrow l\nu D^* \to l\nu D\pi)$. We show that the longitudinal degree of freedom of the off-shell $D^*$ helps to further close the disagreement gap with experimental data. We find values for the ratio $R_{D\pi}^l \equiv {\mathrm{Br}(B\rightarrow \tau\nu_\tau D \pi)}/\mathrm{Br}(B\rightarrow l\nu_l D\pi)$ of $R_{D\pi}^e=0.274\pm0.003$ and $R_{D\pi}^\mu=0.275\pm0.003$, where the uncertainty comes from the uncertainty of the form factors parameters. Comparing against $R_{D\pi}$ reduces the gap with the latest LHCb result from $1.1\sigma$ to $0.48\sigma$, while the gap with the latest Belle result is reduced from $0.42\sigma$ to just $0.10\sigma$ and with the world average results from $3.7\sigma$ to $2.1\sigma$. Erratum added at the end of the file. |
2401.14759 | Hao-Song Li | Hao-Song Li | Ab initio calculation of molecular pentaquark magnetic moments in heavy
pentaquark chiral perturbation theory | null | null | null | null | hep-ph | http://creativecommons.org/licenses/by/4.0/ | We propose a new heavy pentaquark chiral perturbation theory for the recently
observed hidden-charm pentaquark states by LHCb Collaboration. With the ab
initio constructed chiral Lagrangians, we present a parameter-free calculation
of the octet molecular pentaquark magnetic moments up to one-loop level. We
improve the quark model description of the data when we include the leading
SU(3) breaking effects coming from the one-loop corrections. Without any
experimental inputs, our predictions are so simple and unique that we regard
them as a theoretical benchmark to be compared with experiments as well as
other theoretical models.
| [
{
"created": "Fri, 26 Jan 2024 10:34:24 GMT",
"version": "v1"
}
] | 2024-01-29 | [
[
"Li",
"Hao-Song",
""
]
] | We propose a new heavy pentaquark chiral perturbation theory for the recently observed hidden-charm pentaquark states by LHCb Collaboration. With the ab initio constructed chiral Lagrangians, we present a parameter-free calculation of the octet molecular pentaquark magnetic moments up to one-loop level. We improve the quark model description of the data when we include the leading SU(3) breaking effects coming from the one-loop corrections. Without any experimental inputs, our predictions are so simple and unique that we regard them as a theoretical benchmark to be compared with experiments as well as other theoretical models. |
2201.10495 | Juan M. Torres-Rincon | Juan M. Torres-Rincon and Derek Teaney | Kinetics of hydrodynamic pions in chiral perturbation theory | 30.5 pages, 7 figures. Generalization to arbitrary number of flavors,
by considering pion-pion scattering in SU(N) instead of SU(2). Explanations
and extra references added. Accepted for publication in Physical Review D
journal | null | 10.1103/PhysRevD.106.056012 | null | hep-ph nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We determine the kinetic coefficients of ultrasoft pions using chiral
perturbation theory at finite temperature close to the chiral limit. This is
used to compute the axial charge diffusion and damping coefficients in the
hydrodynamic effective theory for these pion waves. We show that to provide a
leading order answer for these coefficients one needs to explore the dynamics
of hard, soft, and ultrasoft pion modes, which are represented microscopically
by the appropriate kinetic and hydrodynamic descriptions..
| [
{
"created": "Tue, 25 Jan 2022 17:38:42 GMT",
"version": "v1"
},
{
"created": "Tue, 13 Sep 2022 16:43:45 GMT",
"version": "v2"
}
] | 2022-10-05 | [
[
"Torres-Rincon",
"Juan M.",
""
],
[
"Teaney",
"Derek",
""
]
] | We determine the kinetic coefficients of ultrasoft pions using chiral perturbation theory at finite temperature close to the chiral limit. This is used to compute the axial charge diffusion and damping coefficients in the hydrodynamic effective theory for these pion waves. We show that to provide a leading order answer for these coefficients one needs to explore the dynamics of hard, soft, and ultrasoft pion modes, which are represented microscopically by the appropriate kinetic and hydrodynamic descriptions.. |
1509.07666 | Gavin Salam | Gavin P. Salam | Summary of the XXVIIth Rencontres de Blois: Particle Physics and
Cosmology | 22 pages, 24 figures, presented at XXVIIth Rencontres de Blois,
France, 31 May - 5 June 2015 | null | null | CERN-PH-TH-2015-234 | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | This writeup summarises some of the highlights from the 2015 Rencontres de
Blois, with a compression ratio of about 100:1 relative to the original
presentations.
| [
{
"created": "Fri, 25 Sep 2015 10:31:22 GMT",
"version": "v1"
}
] | 2015-09-28 | [
[
"Salam",
"Gavin P.",
""
]
] | This writeup summarises some of the highlights from the 2015 Rencontres de Blois, with a compression ratio of about 100:1 relative to the original presentations. |
0706.4212 | Andrej El | A. El, C. Greiner, Z. Xu | Shear Viscosity to Entropy within a Parton Cascade | 2 pages, 4 Figures. Contributed by C.Greiner by Workshop on Heavy Ion
Collisions at the LHC: Last Call for Predictions, Geneva, Switzerland, 14
May-8 Jun 2007 | null | null | null | hep-ph | null | The shear viscosity is calculated by means of the perturbative kinetic
partonic cascade BAMPS with CGC initial conditons for various saturation
momentum scale Q_s. eta/s ~ 0.15 stays approximately constant when going from
RHIC to LHC.
| [
{
"created": "Thu, 28 Jun 2007 12:30:50 GMT",
"version": "v1"
}
] | 2007-06-29 | [
[
"El",
"A.",
""
],
[
"Greiner",
"C.",
""
],
[
"Xu",
"Z.",
""
]
] | The shear viscosity is calculated by means of the perturbative kinetic partonic cascade BAMPS with CGC initial conditons for various saturation momentum scale Q_s. eta/s ~ 0.15 stays approximately constant when going from RHIC to LHC. |
1008.2202 | Michael Spannowsky | Christoph Hackstein, Michael Spannowsky | Boosting Higgs discovery - the forgotten channel | 12 pages, 3 figures | Phys.Rev.D82:113012,2010 | 10.1103/PhysRevD.82.113012 | null | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Searches for a heavy Standard Model Higgs boson focus on the 'gold plated
mode' where the Higgs decays to two leptonic Z bosons. This channel provides a
clean signature, in spite of the small leptonic branching ratios. We show that
using fat jets the semi-leptonic ZZ mode significantly increases the number of
signal events with a similar statistical significance as the leptonic mode.
| [
{
"created": "Thu, 12 Aug 2010 20:00:03 GMT",
"version": "v1"
}
] | 2010-12-28 | [
[
"Hackstein",
"Christoph",
""
],
[
"Spannowsky",
"Michael",
""
]
] | Searches for a heavy Standard Model Higgs boson focus on the 'gold plated mode' where the Higgs decays to two leptonic Z bosons. This channel provides a clean signature, in spite of the small leptonic branching ratios. We show that using fat jets the semi-leptonic ZZ mode significantly increases the number of signal events with a similar statistical significance as the leptonic mode. |
hep-ph/9609422 | Georg Weiglein | A. Denner, S. Dittmaier, G. Weiglein | The background-field formulation of the electroweak Standard Model | 13 pages, LaTeX, no figures. Lecture given by G. Weiglein at the
XXXVI Cracow School of Theoretical Physics, Zakopane, Poland, June 1--10,
1996. The paper is also available via www at
http://www-itp.physik.uni-karlsruhe.de/prep/prep96/preplist96.html | Acta Phys.Polon.B27:3645-3660,1996 | null | BI-TP 96/39, KA-TP-22-1996 | hep-ph | null | The application of the background-field method to the electroweak Standard
Model and its virtues are reviewed. Special emphasis is directed to the Ward
identities that follow from the gauge invariance of the background-field
effective action. They are compatible with on-shell renormalization and imply a
decent behavior of the background-field vertex functions. Via the usual
construction of connected Green functions they transfer to Ward identities for
connected Green functions which, in distinction to the conventional formalism,
remain exactly valid in finite orders of perturbation theory even if a Dyson
summation of self-energies (within a systematic use of one-particle irreducible
building blocks) is performed. Finally, we comment on the interplay between
gauge invariance and gauge-parameter (in-)dependence of vertex and Green
functions and the uniqueness of resummation procedures.
| [
{
"created": "Fri, 20 Sep 1996 16:23:43 GMT",
"version": "v1"
}
] | 2011-04-15 | [
[
"Denner",
"A.",
""
],
[
"Dittmaier",
"S.",
""
],
[
"Weiglein",
"G.",
""
]
] | The application of the background-field method to the electroweak Standard Model and its virtues are reviewed. Special emphasis is directed to the Ward identities that follow from the gauge invariance of the background-field effective action. They are compatible with on-shell renormalization and imply a decent behavior of the background-field vertex functions. Via the usual construction of connected Green functions they transfer to Ward identities for connected Green functions which, in distinction to the conventional formalism, remain exactly valid in finite orders of perturbation theory even if a Dyson summation of self-energies (within a systematic use of one-particle irreducible building blocks) is performed. Finally, we comment on the interplay between gauge invariance and gauge-parameter (in-)dependence of vertex and Green functions and the uniqueness of resummation procedures. |
hep-ph/0412416 | Benjamin Grinstein | Benjamin Grinstein | Heavy Meson Physics: What have we learned in Twenty Years? | This talk was presented during the ceremony awarding the Medalla 2003
of the Division of Particles and Fields of The Mexican Phsyical Society, at
the IX Mexican Workshop on Particles and Fields; submitted for proceedings; 9
pages, 9 figures; replacement: fix multiple typos | J.Phys.Conf.Ser.37:44-58,2006 | 10.1088/1742-6596/37/1/011 | UCSD/PTH 04-18 | hep-ph | null | I give a personal account of the development of the field of heavy quarks.
After reviewing the experimental discovery of charm and bottom quarks, I
describe how the field's focus shifted towards determination of CKM elements
and how this has matured into a precision science.
| [
{
"created": "Thu, 30 Dec 2004 01:55:32 GMT",
"version": "v1"
},
{
"created": "Tue, 4 Jan 2005 02:17:30 GMT",
"version": "v2"
}
] | 2014-11-18 | [
[
"Grinstein",
"Benjamin",
""
]
] | I give a personal account of the development of the field of heavy quarks. After reviewing the experimental discovery of charm and bottom quarks, I describe how the field's focus shifted towards determination of CKM elements and how this has matured into a precision science. |
1204.0340 | Antoni Szczurek | Antoni Szczurek | Production of digluon and quark-antiquark dijets in central exclusive
processes | 7 pages, 8 figures, invited talk at the EDS Blois workshop in Qui
Nhon, Vietnam, December 15-21, 2011 | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We discuss exclusive central production of Higgs boson, quark-antiquark and
digluon dijets. Some differential distributions are shown and disussed.
Irreducible leading-order $b \bar b $ background to Higgs production is
calculated. The signal-to-background ratio is shown and improvements are
suggested by imposing cuts on $b$ ($\bar b$) transverse momenta and rapidities.
We disuss also gluonic dijet production. Here we use rather
reggeon-reggeon-gluon vertices. We discuss briefly also a new mechanism of
emission of gluons from different $t$-channel gluons (reggeons). The latter
contribution turned out to be rather small. When gluons are missidentified as
$b$ or $\bar b$ jets the latter contribution constitutes a reducible but large
contribution to exclusive Standard Model Higgs boson.
| [
{
"created": "Mon, 2 Apr 2012 08:37:58 GMT",
"version": "v1"
}
] | 2012-04-03 | [
[
"Szczurek",
"Antoni",
""
]
] | We discuss exclusive central production of Higgs boson, quark-antiquark and digluon dijets. Some differential distributions are shown and disussed. Irreducible leading-order $b \bar b $ background to Higgs production is calculated. The signal-to-background ratio is shown and improvements are suggested by imposing cuts on $b$ ($\bar b$) transverse momenta and rapidities. We disuss also gluonic dijet production. Here we use rather reggeon-reggeon-gluon vertices. We discuss briefly also a new mechanism of emission of gluons from different $t$-channel gluons (reggeons). The latter contribution turned out to be rather small. When gluons are missidentified as $b$ or $\bar b$ jets the latter contribution constitutes a reducible but large contribution to exclusive Standard Model Higgs boson. |
2401.03732 | Sindhu D G | Sindhu D G, Akhilesh Ranjan, Hemwati Nandan and V. Sharma | Heavy Hexaquarks in the Flux Tube Model | Preprint of an article submitted for consideration in [Modern Physics
Letters A] \c{opyright} [2023] [copyright World Scientific Publishing
Company] [https://www.worldscientific.com/worldscinet/mpla] | Mod. Phys. Lett. A, (2024) 2450008 | 10.1142/S0217732324500081 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Hexaquarks are one of the currently emerging topics in both experimental and
theoretical high energy physics. Hexaquarks have been examined in relation to
particle physics, however, there are still some research and theoretical
conjectures surrounding their relationship to dark matter. Due to some
experimental discoveries, it has attracted much interest and also resulted in
new theoretical models to study the properties of these states. In the present
work, Regge trajectories of some hexaquark states are compared with tetraquark
and pentaquark states. The study is mainly concentrated on fully heavy
hexaquark states. The mass spectra of these hexaquark states have also been
investigated and the results are compared with other theoretical works. Our
findings agree well with those of other researchers.
| [
{
"created": "Mon, 8 Jan 2024 08:41:55 GMT",
"version": "v1"
}
] | 2024-02-09 | [
[
"G",
"Sindhu D",
""
],
[
"Ranjan",
"Akhilesh",
""
],
[
"Nandan",
"Hemwati",
""
],
[
"Sharma",
"V.",
""
]
] | Hexaquarks are one of the currently emerging topics in both experimental and theoretical high energy physics. Hexaquarks have been examined in relation to particle physics, however, there are still some research and theoretical conjectures surrounding their relationship to dark matter. Due to some experimental discoveries, it has attracted much interest and also resulted in new theoretical models to study the properties of these states. In the present work, Regge trajectories of some hexaquark states are compared with tetraquark and pentaquark states. The study is mainly concentrated on fully heavy hexaquark states. The mass spectra of these hexaquark states have also been investigated and the results are compared with other theoretical works. Our findings agree well with those of other researchers. |
hep-ph/9607313 | Juan Antonio Aguilar Saavedra | J. A. Aguilar-Saavedra | Numerical diagonalization of fermion mass matrices | LaTeX, 10 pages, no figures. PostScript available at
http://deneb.ugr.es/papers/ugft67.ps.gz. Package available by anonymous ftp
at deneb.ugr.es in directory pub/packages/ | Int.J.Mod.Phys. C8 (1997) 147-154 | 10.1142/S0129183197000151 | UG-FT-67/96 | hep-ph | null | The diagonalization of general mass matrices is a more delicate problem when
eigenvalue degeneracies exist. In this case, often overlooked in the
literature, some difficulties arise related to the freedom in the choice of
basis in degenerate subspaces. Here two simple algorithms are developed to deal
with quark and neutrino mass matrices with arbitrary degeneracies.
| [
{
"created": "Mon, 15 Jul 1996 12:08:39 GMT",
"version": "v1"
}
] | 2015-06-25 | [
[
"Aguilar-Saavedra",
"J. A.",
""
]
] | The diagonalization of general mass matrices is a more delicate problem when eigenvalue degeneracies exist. In this case, often overlooked in the literature, some difficulties arise related to the freedom in the choice of basis in degenerate subspaces. Here two simple algorithms are developed to deal with quark and neutrino mass matrices with arbitrary degeneracies. |
2404.08622 | Johannes Michel | Rebecca von Kuk, Johannes K. L. Michel, and Zhiquan Sun | Transverse Momentum-Dependent Heavy-Quark Fragmentation at
Next-to-Leading Order | 34 pages + appendices and references, 5 figures; v2: corrected
secondary mass effects in Sec. 6 | null | null | MIT-CTP 5643, DESY-23-174, Nikhef 2023-018 | hep-ph | http://creativecommons.org/licenses/by/4.0/ | The transverse momentum-dependent fragmentation functions (TMD FFs) of heavy
(bottom and charm) quarks, which we recently introduced, are universal building
blocks that enter predictions for a large number of observables involving
final-state heavy quarks or hadrons. They enable the extension of fixed-order
subtraction schemes to quasi-collinear limits, and are of particular interest
in their own right as probes of the nonperturbative dynamics of hadronization.
In this paper we calculate all TMD FFs involving heavy quarks and the
associated TMD matrix element in heavy-quark effective theory (HQET) to
next-to-leading order in the strong interaction. Our results confirm the
renormalization properties, large-mass, and small-mass consistency relations
predicted in our earlier work. We also derive and confirm a prediction for the
large-$z$ behavior of the heavy-quark TMD FF by extending, for the first time,
the formalism of joint resummation to capture quark mass effects in heavy-quark
fragmentation. Our final results in position space agree with those of a recent
calculation by another group that used a highly orthogonal organization of
singularities in the intermediate momentum-space steps, providing a strong
independent cross check. As an immediate application, we present the complete
quark mass dependence of the energy-energy correlator (EEC) in the back-to-back
limit at $\mathcal{O}(\alpha_s)$.
| [
{
"created": "Fri, 12 Apr 2024 17:32:58 GMT",
"version": "v1"
},
{
"created": "Thu, 25 Apr 2024 09:07:53 GMT",
"version": "v2"
}
] | 2024-04-26 | [
[
"von Kuk",
"Rebecca",
""
],
[
"Michel",
"Johannes K. L.",
""
],
[
"Sun",
"Zhiquan",
""
]
] | The transverse momentum-dependent fragmentation functions (TMD FFs) of heavy (bottom and charm) quarks, which we recently introduced, are universal building blocks that enter predictions for a large number of observables involving final-state heavy quarks or hadrons. They enable the extension of fixed-order subtraction schemes to quasi-collinear limits, and are of particular interest in their own right as probes of the nonperturbative dynamics of hadronization. In this paper we calculate all TMD FFs involving heavy quarks and the associated TMD matrix element in heavy-quark effective theory (HQET) to next-to-leading order in the strong interaction. Our results confirm the renormalization properties, large-mass, and small-mass consistency relations predicted in our earlier work. We also derive and confirm a prediction for the large-$z$ behavior of the heavy-quark TMD FF by extending, for the first time, the formalism of joint resummation to capture quark mass effects in heavy-quark fragmentation. Our final results in position space agree with those of a recent calculation by another group that used a highly orthogonal organization of singularities in the intermediate momentum-space steps, providing a strong independent cross check. As an immediate application, we present the complete quark mass dependence of the energy-energy correlator (EEC) in the back-to-back limit at $\mathcal{O}(\alpha_s)$. |
2012.00184 | Breno Chrispim | B. A. S. D. Chrispim, R. C. L. Bruni and M. S. Guimaraes | Massive photon propagator in the presence of axionic fluctuations | 32 pages and 7 figures; added Acknowledgements section; Version to
appear in PhysRevB | Phys. Rev. B 103, 165120 (2021) | 10.1103/PhysRevB.103.165120 | null | hep-ph cond-mat.str-el cond-mat.supr-con hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The theory of massive photons in the presence of axions is studied as the
effective theory describing the electromagnetic response of semimetals when a
particular quartic fermionic pairing perturbation triggers the formation of
charged chiral condensates, giving rise to an axionic superconductor. We
investigate corrections to the Yukawa-like potential mediated by massive
photons due to axion excitations up to one-loop order and compute the
modifications of the London penetration length.
| [
{
"created": "Tue, 1 Dec 2020 00:33:04 GMT",
"version": "v1"
},
{
"created": "Mon, 18 Jan 2021 20:35:04 GMT",
"version": "v2"
},
{
"created": "Fri, 23 Apr 2021 20:43:32 GMT",
"version": "v3"
}
] | 2021-04-27 | [
[
"Chrispim",
"B. A. S. D.",
""
],
[
"Bruni",
"R. C. L.",
""
],
[
"Guimaraes",
"M. S.",
""
]
] | The theory of massive photons in the presence of axions is studied as the effective theory describing the electromagnetic response of semimetals when a particular quartic fermionic pairing perturbation triggers the formation of charged chiral condensates, giving rise to an axionic superconductor. We investigate corrections to the Yukawa-like potential mediated by massive photons due to axion excitations up to one-loop order and compute the modifications of the London penetration length. |
hep-ph/0401057 | Deog Ki Hong | Deog Ki Hong (Pusan Nat'l Univ.) | High Density Effective Theory of QCD | 13 pages, 10 figures, revtex 4, Talk given at Workshop on Finite
Density QCD at Nara, Nara, Japan, 10-12 Jul 2003 and also at NATO Advanced
Research Workshop on Superdense QCD Matter and Compact Stars, Yerevan,
Armenia, 27 Sep - 4 Oct 2003 | Prog.Theor.Phys.Suppl.153:241-258,2004 | 10.1143/PTPS.153.241 | PNUTP-03/A02 | hep-ph | null | We discuss the salient features of the high density effective theory (HDET)
of QCD, elaborating more on the matching for vector-vector correlators and
axial-vector-vector correlators, which are related to screening mass and axial
anomaly, respectively. We then apply HDET to discuss various
color-superconducting phases of dense QCD. We also review a recent proposal to
solve the sign problem in dense fermionic matter, using the positivity property
of HDET. Positivity of HDET allows us to establish rigorous inequalities in QCD
at asymptotic density and to show vector symmetry except the fermion number is
not spontaneously broken at asymptotic density.
| [
{
"created": "Sat, 10 Jan 2004 06:17:51 GMT",
"version": "v1"
}
] | 2008-11-26 | [
[
"Hong",
"Deog Ki",
"",
"Pusan Nat'l Univ."
]
] | We discuss the salient features of the high density effective theory (HDET) of QCD, elaborating more on the matching for vector-vector correlators and axial-vector-vector correlators, which are related to screening mass and axial anomaly, respectively. We then apply HDET to discuss various color-superconducting phases of dense QCD. We also review a recent proposal to solve the sign problem in dense fermionic matter, using the positivity property of HDET. Positivity of HDET allows us to establish rigorous inequalities in QCD at asymptotic density and to show vector symmetry except the fermion number is not spontaneously broken at asymptotic density. |
1105.5367 | Mathias Garny | Mathias Garny, Alejandro Ibarra, Stefan Vogl | Antiproton constraints on dark matter annihilations from internal
electroweak bremsstrahlung | 32 pages; 13 figures | null | 10.1088/1475-7516/2011/07/028 | TUM-HEP 808/11 | hep-ph astro-ph.HE | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | If the dark matter particle is a Majorana fermion, annihilations into two
fermions and one gauge boson could have, for some choices of the parameters of
the model, a non-negligible cross-section. Using a toy model of leptophilic
dark matter, we calculate the constraints on the annihilation cross-section
into two electrons and one weak gauge boson from the PAMELA measurements of the
cosmic antiproton-to-proton flux ratio. Furthermore, we calculate the maximal
astrophysical boost factor allowed in the Milky Way under the assumption that
the leptophilic dark matter particle is the dominant component of dark matter
in our Universe. These constraints constitute very conservative estimates on
the boost factor for more realistic models where the dark matter particle also
couples to quarks and weak gauge bosons, such as the lightest neutralino which
we also analyze for some concrete benchmark points. The limits on the
astrophysical boost factors presented here could be used to evaluate the
prospects to detect a gamma-ray signal from dark matter annihilations at
currently operating IACTs as well as in the projected CTA.
| [
{
"created": "Thu, 26 May 2011 18:16:43 GMT",
"version": "v1"
}
] | 2015-05-28 | [
[
"Garny",
"Mathias",
""
],
[
"Ibarra",
"Alejandro",
""
],
[
"Vogl",
"Stefan",
""
]
] | If the dark matter particle is a Majorana fermion, annihilations into two fermions and one gauge boson could have, for some choices of the parameters of the model, a non-negligible cross-section. Using a toy model of leptophilic dark matter, we calculate the constraints on the annihilation cross-section into two electrons and one weak gauge boson from the PAMELA measurements of the cosmic antiproton-to-proton flux ratio. Furthermore, we calculate the maximal astrophysical boost factor allowed in the Milky Way under the assumption that the leptophilic dark matter particle is the dominant component of dark matter in our Universe. These constraints constitute very conservative estimates on the boost factor for more realistic models where the dark matter particle also couples to quarks and weak gauge bosons, such as the lightest neutralino which we also analyze for some concrete benchmark points. The limits on the astrophysical boost factors presented here could be used to evaluate the prospects to detect a gamma-ray signal from dark matter annihilations at currently operating IACTs as well as in the projected CTA. |
1307.8011 | Philipp Grothaus | Malcolm Fairbairn and Philipp Grothaus | Baryogenesis and Dark Matter with Vector-like Fermions | 21 pages, 11 figures, references added, includes discussion of vacuum
stability, matches published version | null | 10.1007/JHEP10(2013)176 | KCL-PH-TH/2013-23 | hep-ph astro-ph.CO | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We show that vector-like fermions can act as the dark matter candidate in the
universe whilst also playing a crucial role in electroweak baryogenesis through
contributing to the barrier in the one-loop thermal scalar potential. In order
for the new fermions to give rise to a strong first order phase transition, we
show that one requires rather large Yukawa couplings in the new sector, which
are strongly constrained by electroweak precision tests and perturbativity.
Strong couplings between the dark matter candidate and the Higgs boson
intuitively lead to small values of the relic density and problems with dark
matter direct detection bounds. Nevertheless, when considering the most general
realisation of the model, we find regions in the parameter space that respect
all current constraints and may explain both mysteries simultaneously.
| [
{
"created": "Tue, 30 Jul 2013 15:09:29 GMT",
"version": "v1"
},
{
"created": "Tue, 5 Nov 2013 12:24:19 GMT",
"version": "v2"
}
] | 2013-11-06 | [
[
"Fairbairn",
"Malcolm",
""
],
[
"Grothaus",
"Philipp",
""
]
] | We show that vector-like fermions can act as the dark matter candidate in the universe whilst also playing a crucial role in electroweak baryogenesis through contributing to the barrier in the one-loop thermal scalar potential. In order for the new fermions to give rise to a strong first order phase transition, we show that one requires rather large Yukawa couplings in the new sector, which are strongly constrained by electroweak precision tests and perturbativity. Strong couplings between the dark matter candidate and the Higgs boson intuitively lead to small values of the relic density and problems with dark matter direct detection bounds. Nevertheless, when considering the most general realisation of the model, we find regions in the parameter space that respect all current constraints and may explain both mysteries simultaneously. |
hep-ph/0607242 | Sascha Vogel | S. Vogel, M. Bleicher | Resonance Production in Heavy Ion Collisions - what can we learn from
RHIC? | Proceedings of the 22nd Winter Workshop on Nuclear Dynamics | null | null | null | hep-ph | null | In these proceedings we concentrate on the refeeding and rescattering
probability of hadronic resonances. We discuss the probability to form
resonances in binary baryon-meson or meson-meson collisions as a function of
time for various resonances using a transport model approach (UrQMD). We give
an estimate of the re-feeding probability using a simplified thermal approach
and discuss the relevance for the resonance/non-resonance ratio measured by
STAR.
| [
{
"created": "Fri, 21 Jul 2006 14:53:57 GMT",
"version": "v1"
},
{
"created": "Thu, 27 Jul 2006 10:12:36 GMT",
"version": "v2"
},
{
"created": "Thu, 10 Aug 2006 14:10:13 GMT",
"version": "v3"
}
] | 2007-05-23 | [
[
"Vogel",
"S.",
""
],
[
"Bleicher",
"M.",
""
]
] | In these proceedings we concentrate on the refeeding and rescattering probability of hadronic resonances. We discuss the probability to form resonances in binary baryon-meson or meson-meson collisions as a function of time for various resonances using a transport model approach (UrQMD). We give an estimate of the re-feeding probability using a simplified thermal approach and discuss the relevance for the resonance/non-resonance ratio measured by STAR. |
hep-ph/9903287 | Alexandr Andrianov | A. A. Andrianov, V. A. Andrianov, R. Rodenberg | Composite Two-Higgs Models and Chiral Symmetry Restoration | 17 pages, JHEP Latex, in memory of Alexei A.Anselm | JHEP 9906 (1999) 003 | 10.1088/1126-6708/1999/06/003 | PITHA 99/6, Feb.1999 | hep-ph | null | The effective quark models with quasilocal interaction are used for
description of two composite Higgs doublets, in strong coupling (tricritical)
regime below the compositeness scale \Lambda_{C}. The low energy effective
action of Two-Higgs Doublet Standard Model (2HD SM) is obtained in the large
N_c and large-log approximation. The two-point correlators of scalar and
pseudoscalar Higgs fields are derived for investigation of how the chiral
symmetry is broken. The comparison of their asymptotics at high energies allows
to realize the chiral symmetry restoration characteristic for the QCD-like
models and thereby to make hints on the existence of new physical phenomena in
the TeV energy region.
| [
{
"created": "Mon, 8 Mar 1999 14:18:06 GMT",
"version": "v1"
},
{
"created": "Wed, 10 Mar 1999 20:02:41 GMT",
"version": "v2"
}
] | 2009-10-31 | [
[
"Andrianov",
"A. A.",
""
],
[
"Andrianov",
"V. A.",
""
],
[
"Rodenberg",
"R.",
""
]
] | The effective quark models with quasilocal interaction are used for description of two composite Higgs doublets, in strong coupling (tricritical) regime below the compositeness scale \Lambda_{C}. The low energy effective action of Two-Higgs Doublet Standard Model (2HD SM) is obtained in the large N_c and large-log approximation. The two-point correlators of scalar and pseudoscalar Higgs fields are derived for investigation of how the chiral symmetry is broken. The comparison of their asymptotics at high energies allows to realize the chiral symmetry restoration characteristic for the QCD-like models and thereby to make hints on the existence of new physical phenomena in the TeV energy region. |
1707.04557 | Philip Diessner | Philip Diessner, Wojciech Kotlarski, Sebastian Liebschner, Dominik
St\"ockinger | Squark production in R-symmetric SUSY with Dirac gluinos: NLO
corrections | 46 pages, 15 figures; updated to match published version | J. High Energ. Phys. (2017) 2017: 142 | 10.1007/JHEP10(2017)142 | DESY-17-100 | hep-ph | http://creativecommons.org/licenses/by/4.0/ | R-symmetry leads to a distinct realisation of SUSY with a significantly
modified coloured sector featuring a Dirac gluino and a scalar colour octet
(sgluon). We present the impact of R-symmetry on squark production at the 13
TeV LHC. We study the total cross sections and their NLO corrections from all
strongly interacting states, their dependence on the Dirac gluino mass and
sgluon mass as well as their systematics for selected benchmark points. We find
that tree-level cross sections in the R-symmetric model are reduced compared to
the MSSM but the NLO K-factors are generally larger in the order of ten to
twenty per cent. In the course of this work we derive the required DREG $\to$
DRED transition counterterms and necessary on-shell renormalisation constants.
The real corrections are treated using FKS subtraction, with results cross
checked against an independent calculation employing the two cut phase space
slicing method.
| [
{
"created": "Fri, 14 Jul 2017 16:20:27 GMT",
"version": "v1"
},
{
"created": "Wed, 8 Nov 2017 13:41:39 GMT",
"version": "v2"
}
] | 2017-11-22 | [
[
"Diessner",
"Philip",
""
],
[
"Kotlarski",
"Wojciech",
""
],
[
"Liebschner",
"Sebastian",
""
],
[
"Stöckinger",
"Dominik",
""
]
] | R-symmetry leads to a distinct realisation of SUSY with a significantly modified coloured sector featuring a Dirac gluino and a scalar colour octet (sgluon). We present the impact of R-symmetry on squark production at the 13 TeV LHC. We study the total cross sections and their NLO corrections from all strongly interacting states, their dependence on the Dirac gluino mass and sgluon mass as well as their systematics for selected benchmark points. We find that tree-level cross sections in the R-symmetric model are reduced compared to the MSSM but the NLO K-factors are generally larger in the order of ten to twenty per cent. In the course of this work we derive the required DREG $\to$ DRED transition counterterms and necessary on-shell renormalisation constants. The real corrections are treated using FKS subtraction, with results cross checked against an independent calculation employing the two cut phase space slicing method. |
2305.02588 | Chandni Menapara Ms | C. Menapara, A. K. Rai | Properties of N, $\Delta$ Baryons with Screened Potential | 15 pages, 6 figures, Suggestions are welcome | null | null | null | hep-ph | http://creativecommons.org/licenses/by/4.0/ | N and $\Delta$ baryons hold an important place towards understanding the
quark dynamics inside hadrons. The hypercentral Constituent Quark Model (hCQM)
has been employed in various studies ranging from light to heavy hadrons. In
the present article, screened potential has been used to study light baryon
resonances. The Regge trajectories have been plotted alongwith the details of
slopes and intercepts. The strong decay widths to pion have been calculated for
some channels using the present masses.
| [
{
"created": "Thu, 4 May 2023 06:46:13 GMT",
"version": "v1"
}
] | 2023-05-05 | [
[
"Menapara",
"C.",
""
],
[
"Rai",
"A. K.",
""
]
] | N and $\Delta$ baryons hold an important place towards understanding the quark dynamics inside hadrons. The hypercentral Constituent Quark Model (hCQM) has been employed in various studies ranging from light to heavy hadrons. In the present article, screened potential has been used to study light baryon resonances. The Regge trajectories have been plotted alongwith the details of slopes and intercepts. The strong decay widths to pion have been calculated for some channels using the present masses. |
hep-ph/9706225 | Fukuko Yuasa | F. Yuasa, Y. Kurihara, S. Kawabata (High Energy Accelerator Research
Organization, KEK) | $e^+e^- \to b \bar{b} u \bar{d} \mu^- \bar{\nu}_\mu$ with a $t\bar{t}$
production | 17 pages, 8 PostScript figures, LateX; To appear in Phys. Lett. B | Phys.Lett. B414 (1997) 178-186 | 10.1016/S0370-2693(97)01117-9 | KEK Preprint 97-42 | hep-ph | null | The cross section of $e^+e^- \to b \bar{b} u \bar{d} \mu^- \bar{\nu}_\mu$
process with a complete set of tree diagrams, 232 diagrams in the unitary
gauge, was calculated at the energy range of $\sqrt{s}$ = 340 - 500 GeV by
using GRACE system. A main contribution to the cross section comes from
$t\bar{t}$ production, where $t$ and $\bar{t}$ decay into $bu\bar{d}$ and
$\bar{b} \mu^- \bar{\nu}_{\mu}$, respectively. It was found that the
interference between the diagrams with $t\bar{t}$ production and those with
single-$t$ through $ WW $ pair production amounts to 10% at the $t \bar{t}$
threshold energy region. In the energy region above twice of the top quark
mass, more than 95% of the cross section comes from the $t\bar{t}$ diagrams.
| [
{
"created": "Tue, 3 Jun 1997 09:52:51 GMT",
"version": "v1"
},
{
"created": "Fri, 19 Sep 1997 07:57:13 GMT",
"version": "v2"
}
] | 2009-10-30 | [
[
"Yuasa",
"F.",
"",
"High Energy Accelerator Research\n Organization, KEK"
],
[
"Kurihara",
"Y.",
"",
"High Energy Accelerator Research\n Organization, KEK"
],
[
"Kawabata",
"S.",
"",
"High Energy Accelerator Research\n Organization, KEK"
]
] | The cross section of $e^+e^- \to b \bar{b} u \bar{d} \mu^- \bar{\nu}_\mu$ process with a complete set of tree diagrams, 232 diagrams in the unitary gauge, was calculated at the energy range of $\sqrt{s}$ = 340 - 500 GeV by using GRACE system. A main contribution to the cross section comes from $t\bar{t}$ production, where $t$ and $\bar{t}$ decay into $bu\bar{d}$ and $\bar{b} \mu^- \bar{\nu}_{\mu}$, respectively. It was found that the interference between the diagrams with $t\bar{t}$ production and those with single-$t$ through $ WW $ pair production amounts to 10% at the $t \bar{t}$ threshold energy region. In the energy region above twice of the top quark mass, more than 95% of the cross section comes from the $t\bar{t}$ diagrams. |
1904.02631 | Nikolaos Stefanis | N. G. Stefanis | Pion-photon transition form factor in QCD. Theoretical predictions and
topology-based data analysis | 26 pages, 2 tables, 9 figures, uses two-column format. In V2, url's
in [22] and [24] removed to resolve problem with format. V3 contains in Figs.
2, 3, 8, 9 comparison with preliminary BESIII data [48] and extended
explanations in text | null | null | RUB-TPII-01/2019 | hep-ph hep-ex hep-lat physics.data-an | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We discuss the evaluation of the transition form factor (TFF)
$F^{\gamma*\gamma\pi^0}(Q^2)$ by means of QCD theory and by state-space
reconstruction from topological data analysis. We first calculate this quantity
in terms of quark-gluon interactions using light cone sum rules (LCSRs). The
spectral density includes radiative corrections in leading, next-to-leading,
and next-to-next-to-leading-order of perturbative QCD. Besides, it takes into
account the twist-four and twist-six terms. The hard-scattering part in the
LCSR is convoluted with various pion distribution amplitudes with different
morphologies in order to obtain a wide range of predictions for the form
factor, including two-loop evolution which accounts for heavy-quark thresholds.
We then use nonlinear time series analysis to extract information on the
long-term $Q^2$ behavior of the measured scaled form factor in terms of
state-space attractors embedded in $\mathbb{R}^3$. These are reconstructed by
applying the Packard-Takens method of delays to appropriate samplings of the
data obtained in the CLEO, \textit{BABAR}, and Belle single-tagged $e^+e^- \to
e^+e^-\pi^0$ experiments. The corresponding lag plots show an aggregation of
states around the value $Q^2F^{\gamma*\gamma\pi^0}(Q^2) \approx 0.165\pm 0.005$
GeV pertaining to the momentum interval $Q^2\in [9-11]$~GeV$^2$. We argue that
this attractor portrait is a transient precursor of a distribution of states
peaking closer to the asymptotic limit $Q^2F^{\gamma*\gamma\pi^0}(Q^2\to
\infty)=\sqrt{2}f_\pi$~GeV. More data with a regular increment of 1~GeV$^2$ in
the range between 10 and 25~GeV$^2$ would be sufficient to faithfully determine
the terminal portrait of the attractor.
| [
{
"created": "Thu, 4 Apr 2019 16:04:02 GMT",
"version": "v1"
},
{
"created": "Fri, 5 Apr 2019 16:20:35 GMT",
"version": "v2"
},
{
"created": "Thu, 20 Jun 2019 14:21:41 GMT",
"version": "v3"
}
] | 2019-06-21 | [
[
"Stefanis",
"N. G.",
""
]
] | We discuss the evaluation of the transition form factor (TFF) $F^{\gamma*\gamma\pi^0}(Q^2)$ by means of QCD theory and by state-space reconstruction from topological data analysis. We first calculate this quantity in terms of quark-gluon interactions using light cone sum rules (LCSRs). The spectral density includes radiative corrections in leading, next-to-leading, and next-to-next-to-leading-order of perturbative QCD. Besides, it takes into account the twist-four and twist-six terms. The hard-scattering part in the LCSR is convoluted with various pion distribution amplitudes with different morphologies in order to obtain a wide range of predictions for the form factor, including two-loop evolution which accounts for heavy-quark thresholds. We then use nonlinear time series analysis to extract information on the long-term $Q^2$ behavior of the measured scaled form factor in terms of state-space attractors embedded in $\mathbb{R}^3$. These are reconstructed by applying the Packard-Takens method of delays to appropriate samplings of the data obtained in the CLEO, \textit{BABAR}, and Belle single-tagged $e^+e^- \to e^+e^-\pi^0$ experiments. The corresponding lag plots show an aggregation of states around the value $Q^2F^{\gamma*\gamma\pi^0}(Q^2) \approx 0.165\pm 0.005$ GeV pertaining to the momentum interval $Q^2\in [9-11]$~GeV$^2$. We argue that this attractor portrait is a transient precursor of a distribution of states peaking closer to the asymptotic limit $Q^2F^{\gamma*\gamma\pi^0}(Q^2\to \infty)=\sqrt{2}f_\pi$~GeV. More data with a regular increment of 1~GeV$^2$ in the range between 10 and 25~GeV$^2$ would be sufficient to faithfully determine the terminal portrait of the attractor. |
0901.1903 | Dmitri Kharzeev | Theodor Brasoveanu, Dmitri Kharzeev and Mauricio Martinez | In search of the QCD-Gravity correspondence | 31 pages, 7 figures; Lectures delivered by D. Kharzeev at the
International QGP Winter School, Jaipur, India, February 1-3, 2008 | Lect.Notes Phys.785:341-369,2010 | 10.1007/978-3-642-02286-9_10 | null | hep-ph hep-th nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Quantum Chromodynamics (QCD) is the fundamental theory of strong
interactions. It describes the behavior of quarks and gluons which are the
smallest known constituents of nuclear matter. The difficulties in solving the
theory at low energies in the strongly interacting, non-perturbative regime
have left unanswered many important questions in QCD, such as the nature of
confinement or the mechanism of hadronization. In these lectures oriented
towards the students we introduce two classes of dualities that attempt to
reproduce many of the features of QCD, while making the treatment at strong
coupling more tractable: (1) the AdS/CFT correspondence between a specific
class of string theories and a conformal field theory and (2) an effective
low-energy theory of QCD dual to classical QCD on a curved conformal
gravitational background. The hope is that by applying these dualities to the
evaluation of various properties of the strongly-interacting matter produced in
heavy ion collisions one can understand how QCD behaves at strong coupling. We
give an outline of the applications, with emphasis on two transport
coefficients of QCD matter -- shear and bulk viscosities.
| [
{
"created": "Tue, 13 Jan 2009 22:55:49 GMT",
"version": "v1"
}
] | 2009-12-22 | [
[
"Brasoveanu",
"Theodor",
""
],
[
"Kharzeev",
"Dmitri",
""
],
[
"Martinez",
"Mauricio",
""
]
] | Quantum Chromodynamics (QCD) is the fundamental theory of strong interactions. It describes the behavior of quarks and gluons which are the smallest known constituents of nuclear matter. The difficulties in solving the theory at low energies in the strongly interacting, non-perturbative regime have left unanswered many important questions in QCD, such as the nature of confinement or the mechanism of hadronization. In these lectures oriented towards the students we introduce two classes of dualities that attempt to reproduce many of the features of QCD, while making the treatment at strong coupling more tractable: (1) the AdS/CFT correspondence between a specific class of string theories and a conformal field theory and (2) an effective low-energy theory of QCD dual to classical QCD on a curved conformal gravitational background. The hope is that by applying these dualities to the evaluation of various properties of the strongly-interacting matter produced in heavy ion collisions one can understand how QCD behaves at strong coupling. We give an outline of the applications, with emphasis on two transport coefficients of QCD matter -- shear and bulk viscosities. |
0903.3691 | George Leontaris | G. K. Leontaris | Instanton induced charged fermion and neutrino masses in a minimal
Standard Model scenario from intersecting D-branes | 17 pages, 3 figures | Int.J.Mod.Phys.A24:6035-6049,2009 | 10.1142/S0217751X09047351 | null | hep-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | String instanton Yukawa corrections from Euclidean D-branes are investigated
in an effective Standard Model theory obtained from the minimal U(3)xU(2)xU(1)
D-brane configuration. In the case of the minimal chiral and Higgs spectrum, it
is found that superpotential contributions are induced by string instantons for
the perturbatively forbidden entries of the up and down quark mass matrices.
Analogous non-perturbative effects generate heavy Majorana neutrino masses and
a Dirac neutrino texture with factorizable Yukawa couplings. For this latter
case, a specific example is worked out where it is shown how this texture can
reconcile the neutrino data.
| [
{
"created": "Sat, 21 Mar 2009 21:08:05 GMT",
"version": "v1"
}
] | 2010-01-21 | [
[
"Leontaris",
"G. K.",
""
]
] | String instanton Yukawa corrections from Euclidean D-branes are investigated in an effective Standard Model theory obtained from the minimal U(3)xU(2)xU(1) D-brane configuration. In the case of the minimal chiral and Higgs spectrum, it is found that superpotential contributions are induced by string instantons for the perturbatively forbidden entries of the up and down quark mass matrices. Analogous non-perturbative effects generate heavy Majorana neutrino masses and a Dirac neutrino texture with factorizable Yukawa couplings. For this latter case, a specific example is worked out where it is shown how this texture can reconcile the neutrino data. |
hep-ph/0208126 | Igor Anikin | I.V. Anikin (JINR, Dubna), O.V. Teryaev (JINR, Dubna) | Non-factorized genuine twist 3 in exclusive electro-production of vector
mesons | 4 pages. Talk presented by I.V. Anikin at European Workshop on the
QCD Structure of the Nucleon (QCD-N'02), Ferrara, Italy, 3-6 Apr 2002 (to
appear in Nucl. Phys. A, Proc. Suppl.) | Nucl.Phys. A711 (2002) 199-202 | 10.1016/S0375-9474(02)01216-2 | null | hep-ph | null | We present an analysis of genuine twist-3 quark contributions to the
amplitude of exclusive electro-production of transversely polarized vector
mesons. Using the formalism based on the momentum representation we calculated
all the genuine twist-3 terms of quark contributions to gamma_T^* --> rho_T
amplitude. We found that these terms can not be factorized owing to the
existence of the infrared divergencies in the amplitude of hard sub-processes.
| [
{
"created": "Tue, 13 Aug 2002 15:49:20 GMT",
"version": "v1"
}
] | 2009-11-07 | [
[
"Anikin",
"I. V.",
"",
"JINR, Dubna"
],
[
"Teryaev",
"O. V.",
"",
"JINR, Dubna"
]
] | We present an analysis of genuine twist-3 quark contributions to the amplitude of exclusive electro-production of transversely polarized vector mesons. Using the formalism based on the momentum representation we calculated all the genuine twist-3 terms of quark contributions to gamma_T^* --> rho_T amplitude. We found that these terms can not be factorized owing to the existence of the infrared divergencies in the amplitude of hard sub-processes. |
hep-ph/9502215 | Stanislaw Mrowczynski | Stanislaw Mrowczynski | Sum rule of the correlation function | 6 pages, no macros | Phys.Lett. B345 (1995) 393-396 | 10.1016/0370-2693(94)01631-L | null | hep-ph | null | We derive a sum rule satisfied by the correlation function of two particles
with small relative momenta, which results from the completeness condition of
the quantum states.
| [
{
"created": "Thu, 2 Feb 1995 09:39:33 GMT",
"version": "v1"
}
] | 2009-10-28 | [
[
"Mrowczynski",
"Stanislaw",
""
]
] | We derive a sum rule satisfied by the correlation function of two particles with small relative momenta, which results from the completeness condition of the quantum states. |
1902.07200 | Jorge Fern\'andez Soriano | Jorge F. Soriano, Antonio L. Maroto | Isotropic charged cosmologies in infrared-modified electrodynamics | 10 pages, 6 figures | Phys. Rev. D 100, 083532 (2019) | 10.1103/PhysRevD.100.083532 | null | hep-ph astro-ph.CO gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | It has long been known that the covariant formulation of quantum
electrodynamics conflicts with the local description of states in the charged
sector. Some of the solutions to this problem amount to modifications of the
subsidiary conditions below some arbitrarily low photon frequency. Such
infrared modified theories have been shown to be equivalent to standard Maxwell
electrodynamics with an additional classical electromagnetic current induced by
the quantum charges. The induced current only has support for very small
frequencies and cancels the effects of the physical charges on large scales. In
this work we explore the possibility that this de-electrification effect could
allow for the existence of isotropic charged cosmologies, thus evading the
stringent limits on the electric charge asymmetry of the universe. We consider
a simple model of infrared-modified scalar electrodynamics in the cosmological
context and find that the charged sector generates a new contribution to the
energy-momentum tensor whose dominant contribution at late times is a
cosmological constant-like term. If the charge asymmetry was generated during
inflation, the limits on the asymmetry parameter in order not to produce a
too-large cosmological constant are very stringent $\eta_Q <10^{-131}-
10^{-144}$ for a number of e-folds $N=50-60$ in typical models. However if the
charge imbalance is produced after inflation, the limits are relaxed in such a
way that $\eta_Q<10^{-43}(100 \,\mbox{GeV}/T_Q)$, with $T_Q$ the temperature at
which the asymmetry was generated. If the charge asymmetry has ever existed and
the associated electromagnetic fields vanish in the asymptotic future, the
limit can be further reduced to $\eta_Q<10^{-28}$.
| [
{
"created": "Tue, 19 Feb 2019 18:54:16 GMT",
"version": "v1"
},
{
"created": "Wed, 12 Jun 2019 21:58:16 GMT",
"version": "v2"
},
{
"created": "Mon, 18 Nov 2019 04:53:48 GMT",
"version": "v3"
}
] | 2019-11-19 | [
[
"Soriano",
"Jorge F.",
""
],
[
"Maroto",
"Antonio L.",
""
]
] | It has long been known that the covariant formulation of quantum electrodynamics conflicts with the local description of states in the charged sector. Some of the solutions to this problem amount to modifications of the subsidiary conditions below some arbitrarily low photon frequency. Such infrared modified theories have been shown to be equivalent to standard Maxwell electrodynamics with an additional classical electromagnetic current induced by the quantum charges. The induced current only has support for very small frequencies and cancels the effects of the physical charges on large scales. In this work we explore the possibility that this de-electrification effect could allow for the existence of isotropic charged cosmologies, thus evading the stringent limits on the electric charge asymmetry of the universe. We consider a simple model of infrared-modified scalar electrodynamics in the cosmological context and find that the charged sector generates a new contribution to the energy-momentum tensor whose dominant contribution at late times is a cosmological constant-like term. If the charge asymmetry was generated during inflation, the limits on the asymmetry parameter in order not to produce a too-large cosmological constant are very stringent $\eta_Q <10^{-131}- 10^{-144}$ for a number of e-folds $N=50-60$ in typical models. However if the charge imbalance is produced after inflation, the limits are relaxed in such a way that $\eta_Q<10^{-43}(100 \,\mbox{GeV}/T_Q)$, with $T_Q$ the temperature at which the asymmetry was generated. If the charge asymmetry has ever existed and the associated electromagnetic fields vanish in the asymptotic future, the limit can be further reduced to $\eta_Q<10^{-28}$. |
2401.05174 | Sanjoy Mandal | Eung Jin Chun, Sanjoy Mandal and Rojalin Padhan | Collider imprints of right handed neutrino magnetic moment operator | 28 pages, 10 figures | null | null | null | hep-ph | http://creativecommons.org/licenses/by/4.0/ | We consider most general effective Lagrangian up to dimension five, built
with Standard Model~(SM) fields and right-handed neutrinos~(RHNs) $N_i$.
Assuming that the RHNs are present near the electroweak scale, we study the
phenomenology of the RHNs and highlight the differences that arise due to the
inclusion of dimension five operators. We specifically focus on the production
process $e^+e^-/pp\to N_i N_j$ which comes from the dimension five magnetic
moment operator. We find that this production process followed by the decay
chains such as $N_i\to N_j\gamma$, $N_i\to\nu_j\gamma$ and $N_i\to\ell^\pm j j$
leads to striking collider signatures which might help to probe the Majorana
nature of neutrinos. We discuss the current collider constraints on this
operator, as well as projected limit at future colliders. In addition, we
discuss the stellar-cooling bounds applicable to the RHN mass below 0.1 GeV.
| [
{
"created": "Wed, 10 Jan 2024 14:17:24 GMT",
"version": "v1"
}
] | 2024-01-11 | [
[
"Chun",
"Eung Jin",
""
],
[
"Mandal",
"Sanjoy",
""
],
[
"Padhan",
"Rojalin",
""
]
] | We consider most general effective Lagrangian up to dimension five, built with Standard Model~(SM) fields and right-handed neutrinos~(RHNs) $N_i$. Assuming that the RHNs are present near the electroweak scale, we study the phenomenology of the RHNs and highlight the differences that arise due to the inclusion of dimension five operators. We specifically focus on the production process $e^+e^-/pp\to N_i N_j$ which comes from the dimension five magnetic moment operator. We find that this production process followed by the decay chains such as $N_i\to N_j\gamma$, $N_i\to\nu_j\gamma$ and $N_i\to\ell^\pm j j$ leads to striking collider signatures which might help to probe the Majorana nature of neutrinos. We discuss the current collider constraints on this operator, as well as projected limit at future colliders. In addition, we discuss the stellar-cooling bounds applicable to the RHN mass below 0.1 GeV. |
1801.10159 | Mukul Sholapurkar | Rouven Essig, Mukul Sholapurkar, Tien-Tien Yu | Solar Neutrinos as a Signal and Background in Direct-Detection
Experiments Searching for Sub-GeV Dark Matter With Electron Recoils | 17 pages + refs, 15 figures, 4 tables. v3 minor corrections. Scaling
of Fig. 9 corrected. Minor corrections to Fig. 4,7,8 and 15. Conclusions
unchanged | Phys. Rev. D 97, 095029 (2018) | 10.1103/PhysRevD.97.095029 | YITP-SB-17-36, CERN-TH-2017-194 | hep-ph astro-ph.CO | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Direct-detection experiments sensitive to low-energy electron recoils from
sub-GeV dark matter (DM) interactions will also be sensitive to solar neutrinos
via coherent neutrino-nucleus scattering (CNS), since the recoiling nucleus can
produce a small ionization signal. Solar neutrinos constitute both an
interesting signal in their own right and a potential background to a DM search
that cannot be controlled or reduced by improved shielding, material
purification and handling, or improved detector design. We explore these two
possibilities in detail for semiconductor (Si and Ge) and Xe targets,
considering several possibilities for the unmeasured ionization efficiency at
low energies. For DM-electron-scattering searches, neutrinos start being an
important background for exposures larger than ~1-10 kg-years in Si and Ge, and
for exposures larger than ~0.1-1 kg-year in Xe. For the absorption of bosonic
DM (dark photons and axion-like particles) by electrons, neutrinos are most
relevant for masses below ~1 keV and again slightly more important in Xe.
Treating the neutrinos as a signal, we find that the CNS of B-8 neutrinos can
be observed with ~2 sigma significance with exposures of ~2, 7, and 20 kg-years
in Xe, Ge, and Si, respectively, assuming there are no other backgrounds. We
give an example for how this would constrain non-standard neutrino
interactions. Neutrino components at lower energy can only be detected if the
ionization efficiency is sufficiently large. In this case, observing pep
neutrinos via CNS requires exposures ~10-100 kg-years in Si or Ge (~1000
kg-years in Xe), and observing CNO neutrinos would require an order of
magnitude more exposure. Only Si could potentially detect Be-7 neutrinos. These
measurements would allow for a direct measurement of the electron-neutrino
survival probability over a wide energy range.
| [
{
"created": "Tue, 30 Jan 2018 19:00:00 GMT",
"version": "v1"
},
{
"created": "Sat, 2 Jun 2018 18:17:50 GMT",
"version": "v2"
},
{
"created": "Wed, 19 Sep 2018 05:46:37 GMT",
"version": "v3"
}
] | 2018-09-20 | [
[
"Essig",
"Rouven",
""
],
[
"Sholapurkar",
"Mukul",
""
],
[
"Yu",
"Tien-Tien",
""
]
] | Direct-detection experiments sensitive to low-energy electron recoils from sub-GeV dark matter (DM) interactions will also be sensitive to solar neutrinos via coherent neutrino-nucleus scattering (CNS), since the recoiling nucleus can produce a small ionization signal. Solar neutrinos constitute both an interesting signal in their own right and a potential background to a DM search that cannot be controlled or reduced by improved shielding, material purification and handling, or improved detector design. We explore these two possibilities in detail for semiconductor (Si and Ge) and Xe targets, considering several possibilities for the unmeasured ionization efficiency at low energies. For DM-electron-scattering searches, neutrinos start being an important background for exposures larger than ~1-10 kg-years in Si and Ge, and for exposures larger than ~0.1-1 kg-year in Xe. For the absorption of bosonic DM (dark photons and axion-like particles) by electrons, neutrinos are most relevant for masses below ~1 keV and again slightly more important in Xe. Treating the neutrinos as a signal, we find that the CNS of B-8 neutrinos can be observed with ~2 sigma significance with exposures of ~2, 7, and 20 kg-years in Xe, Ge, and Si, respectively, assuming there are no other backgrounds. We give an example for how this would constrain non-standard neutrino interactions. Neutrino components at lower energy can only be detected if the ionization efficiency is sufficiently large. In this case, observing pep neutrinos via CNS requires exposures ~10-100 kg-years in Si or Ge (~1000 kg-years in Xe), and observing CNO neutrinos would require an order of magnitude more exposure. Only Si could potentially detect Be-7 neutrinos. These measurements would allow for a direct measurement of the electron-neutrino survival probability over a wide energy range. |
0901.2504 | Stefano Forte | M. Dittmar, S. Forte, A. Glazov, S. Moch (convenors), G. Altarelli, J.
Anderson, R. D. Ball, G. Beuf, M. Boonekamp, H. Burkhardt, F. Caola, M.
Ciafaloni, D. Colferai, A. Cooper-Sarkar, A. de Roeck, L. Del Debbio, J.
Feltesse, F. Gelis, J. Grebenyuk, A. Guffanti, V. Halyo, J. I. Latorre, V.
Lendermann, Gang Li, L. Motyka, T. Petersen, A. Piccione, V. Radescu, M.
Rogal, J. Rojo, C. Royon, G. P. Salam, D. Salek, A. M. Stasto, R. S. Thorne,
M. Ubiali, J. A. M. Vermaseren, A. Vogt, G. Watt, C. D. White | Parton Distributions | 99 pages, 61 figures; summary report of Working Group I for the
HERA-LHC workshop. Requires cernrep.cls and mcite.sty. Various typos
corrected | null | null | IFUM-936-FT | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We provide an assessment of the state of the art in various issues related to
experimental measurements, phenomenological methods and theoretical results
relevant for the determination of parton distribution functions (PDFs) and
their uncertainties, with the specific aim of providing benchmarks of different
existing approaches and results in view of their application to physics at the
LHC. We discuss higher order corrections, we review and compare different
approaches to small x resummation, and we assess the possible relevance of
parton saturation in the determination of PDFS at HERA and its possible study
in LHC processes. We provide various benchmarks of PDF fits, with the specific
aim of studying issues of error propagation, non-gaussian uncertainties, choice
of functional forms of PDFs, and combination of data from different experiments
and different processes. We study the impact of combined HERA (ZEUS-H1)
structure function data, their impact on PDF uncertainties, and their
implications for the computation of standard candle processes, and we review
the recent F_L determination at HERA. Finally, we compare and assess methods
for luminosity measurements at the LHC and the impact of PDFs on them.
| [
{
"created": "Fri, 16 Jan 2009 15:14:30 GMT",
"version": "v1"
},
{
"created": "Fri, 23 Jan 2009 11:09:18 GMT",
"version": "v2"
}
] | 2009-01-23 | [
[
"Dittmar",
"M.",
"",
"convenors"
],
[
"Forte",
"S.",
"",
"convenors"
],
[
"Glazov",
"A.",
"",
"convenors"
],
[
"Moch",
"S.",
"",
"convenors"
],
[
"Altarelli",
"G.",
""
],
[
"Anderson",
"J.",
""
],
[
... | We provide an assessment of the state of the art in various issues related to experimental measurements, phenomenological methods and theoretical results relevant for the determination of parton distribution functions (PDFs) and their uncertainties, with the specific aim of providing benchmarks of different existing approaches and results in view of their application to physics at the LHC. We discuss higher order corrections, we review and compare different approaches to small x resummation, and we assess the possible relevance of parton saturation in the determination of PDFS at HERA and its possible study in LHC processes. We provide various benchmarks of PDF fits, with the specific aim of studying issues of error propagation, non-gaussian uncertainties, choice of functional forms of PDFs, and combination of data from different experiments and different processes. We study the impact of combined HERA (ZEUS-H1) structure function data, their impact on PDF uncertainties, and their implications for the computation of standard candle processes, and we review the recent F_L determination at HERA. Finally, we compare and assess methods for luminosity measurements at the LHC and the impact of PDFs on them. |
1703.05947 | Gabor Andras Almasi | Gabor Almasi, Bengt Friman, Krzysztof Redlich | Baryon number fluctuations in chiral effective models and their
phenomenological implications | 15 pages, 13 figures | Phys. Rev. D 96, 014027 (2017) | 10.1103/PhysRevD.96.014027 | null | hep-ph nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study the critical properties of net-baryon-number fluctuations at the
chiral restoration transition in a medium at finite temperature and net baryon
density. The chiral dynamics of quantum chromodynamics (QCD) is modeled by the
Polykov-loop extended Quark-Meson Lagrangian, that includes the coupling of
quarks to vector meson and temporal gauge fields. The Functional
Renormalization Group is employed to properly account for the $O(4)$
criticality at the phase boundary. We focus on the properties and systematics
of ratios of the net-baryon-number cumulants $\chi_B^n$, for ${1\leq n\leq 6}$,
near the phase boundary. The results are presented in the context of the recent
experimental data of the STAR Collaboration on fluctuations of the net proton
number in heavy ion collisions at RHIC. We show that the model results for the
energy dependence of the cumulant ratios are in good overall agreement with the
data, with one exception. At center-of-mass energies below
${19.6\;\mathrm{GeV}}$, we find that the measured fourth-order cumulant
deviates considerably from the model results, which incorporate the expected
$O(4)$ and $Z(2)$ criticality. We assess the influence of model assumptions and
in particular of repulsive vector-interactions, which are used to modify the
location of the critical endpoint in the model, on the cumulants ratios.
Finally, we discuss a possibility to test to what extent the fluctuations are
affected by nonequilibrium dynamics by comparing certain ratios of cumulants.
| [
{
"created": "Fri, 17 Mar 2017 10:05:50 GMT",
"version": "v1"
}
] | 2017-08-02 | [
[
"Almasi",
"Gabor",
""
],
[
"Friman",
"Bengt",
""
],
[
"Redlich",
"Krzysztof",
""
]
] | We study the critical properties of net-baryon-number fluctuations at the chiral restoration transition in a medium at finite temperature and net baryon density. The chiral dynamics of quantum chromodynamics (QCD) is modeled by the Polykov-loop extended Quark-Meson Lagrangian, that includes the coupling of quarks to vector meson and temporal gauge fields. The Functional Renormalization Group is employed to properly account for the $O(4)$ criticality at the phase boundary. We focus on the properties and systematics of ratios of the net-baryon-number cumulants $\chi_B^n$, for ${1\leq n\leq 6}$, near the phase boundary. The results are presented in the context of the recent experimental data of the STAR Collaboration on fluctuations of the net proton number in heavy ion collisions at RHIC. We show that the model results for the energy dependence of the cumulant ratios are in good overall agreement with the data, with one exception. At center-of-mass energies below ${19.6\;\mathrm{GeV}}$, we find that the measured fourth-order cumulant deviates considerably from the model results, which incorporate the expected $O(4)$ and $Z(2)$ criticality. We assess the influence of model assumptions and in particular of repulsive vector-interactions, which are used to modify the location of the critical endpoint in the model, on the cumulants ratios. Finally, we discuss a possibility to test to what extent the fluctuations are affected by nonequilibrium dynamics by comparing certain ratios of cumulants. |
2204.11885 | Anirban Das | Anirban Das, Yuber F. Perez-Gonzalez, and Manibrata Sen | Neutrino secret self-interactions: a booster shot for the cosmic
neutrino background | v1: 9 pages, 6 figures, v2: Figures improved, references added, v3:
Text improved, matches published version | null | 10.1103/PhysRevD.106.095042 | SLAC-PUB-17673, IPPP/22/24 | hep-ph astro-ph.CO astro-ph.HE | http://creativecommons.org/licenses/by/4.0/ | Neutrinos might interact among themselves through forces that have so far
remained hidden. Throughout the history of the Universe, such \emph{secret}
interactions could lead to scatterings between the neutrinos from supernova
explosions and the non-relativistic relic neutrinos left over from the Big
Bang. Such scatterings can boost the cosmic neutrino background (C$\nu$B) to
energies of ${\cal O}$(MeV), making it, in principle, observable in experiments
searching for the diffuse supernova neutrino background. Assuming a
model-independent, but flavor universal, four-Fermi interaction, we determine
the upscattered cosmic neutrino flux, and derive constraints on such secret
interactions from the latest results from Super-Kamiokande. Furthermore, we
also study prospects for detection of the boosted flux in future lead-based
coherent elastic neutrino-nucleus scattering experiments. Nevertheless, given
current constraints on flavor universal self-interactions, we find that the
upscattered C$\nu$B~contribution to the total DSNB flux is negligible, making a
possible measurement of the boosted C$\nu$B insurmountable.
| [
{
"created": "Mon, 25 Apr 2022 18:00:08 GMT",
"version": "v1"
},
{
"created": "Wed, 27 Apr 2022 16:45:40 GMT",
"version": "v2"
},
{
"created": "Mon, 9 Jan 2023 23:52:57 GMT",
"version": "v3"
}
] | 2023-01-11 | [
[
"Das",
"Anirban",
""
],
[
"Perez-Gonzalez",
"Yuber F.",
""
],
[
"Sen",
"Manibrata",
""
]
] | Neutrinos might interact among themselves through forces that have so far remained hidden. Throughout the history of the Universe, such \emph{secret} interactions could lead to scatterings between the neutrinos from supernova explosions and the non-relativistic relic neutrinos left over from the Big Bang. Such scatterings can boost the cosmic neutrino background (C$\nu$B) to energies of ${\cal O}$(MeV), making it, in principle, observable in experiments searching for the diffuse supernova neutrino background. Assuming a model-independent, but flavor universal, four-Fermi interaction, we determine the upscattered cosmic neutrino flux, and derive constraints on such secret interactions from the latest results from Super-Kamiokande. Furthermore, we also study prospects for detection of the boosted flux in future lead-based coherent elastic neutrino-nucleus scattering experiments. Nevertheless, given current constraints on flavor universal self-interactions, we find that the upscattered C$\nu$B~contribution to the total DSNB flux is negligible, making a possible measurement of the boosted C$\nu$B insurmountable. |
hep-ph/0703104 | Carlos A. Salgado | Kari J. Eskola, Vesa J. Kolhinen, Hannu Paukkunen and Carlos A.
Salgado | A global reanalysis of nuclear parton distribution functions | 33 pages, 14 figures | JHEP 0705:002,2007 | 10.1088/1126-6708/2007/05/002 | HIP-2007-10/TH, Roma1-1448/2007 | hep-ph | null | We determine the nuclear modifications of parton distribution functions of
bound protons at scales $Q^2\ge 1.69$ GeV$^2$ and momentum fractions
$10^{-5}\le x\le 1$ in a global analysis which utilizes nuclear hard process
data, sum rules and leading-order DGLAP scale evolution. The main improvements
over our earlier work {\em EKS98} are the automated $\chi^2$ minimization,
simplified and better controllable fit functions, and most importantly, the
possibility for error estimates. The resulting 16-parameter fit to the N=514
datapoints is good, $\chi^2/{\rm d.o.f}=0.82$. Within the error estimates
obtained, the old {\em EKS98} parametrization is found to be fully consistent
with the present analysis, with no essential difference in terms of $\chi^2$
either. We also determine separate uncertainty bands for the nuclear gluon and
sea quark modifications in the large-$x$ region where they are not stringently
constrained by the available data. Comparison with other global analyses is
shown and uncertainties demonstrated. Finally, we show that RHIC-BRAHMS data
for inclusive hadron production in d+Au collisions lend support for a stronger
gluon shadowing at $x<0.01$ and also that fairly large changes in the gluon
modifications do not rapidly deteriorate the goodness of the overall fits, as
long as the initial gluon modifications in the region $x\sim 0.02-0.04$ remain
small.
| [
{
"created": "Fri, 9 Mar 2007 14:36:56 GMT",
"version": "v1"
}
] | 2014-11-18 | [
[
"Eskola",
"Kari J.",
""
],
[
"Kolhinen",
"Vesa J.",
""
],
[
"Paukkunen",
"Hannu",
""
],
[
"Salgado",
"Carlos A.",
""
]
] | We determine the nuclear modifications of parton distribution functions of bound protons at scales $Q^2\ge 1.69$ GeV$^2$ and momentum fractions $10^{-5}\le x\le 1$ in a global analysis which utilizes nuclear hard process data, sum rules and leading-order DGLAP scale evolution. The main improvements over our earlier work {\em EKS98} are the automated $\chi^2$ minimization, simplified and better controllable fit functions, and most importantly, the possibility for error estimates. The resulting 16-parameter fit to the N=514 datapoints is good, $\chi^2/{\rm d.o.f}=0.82$. Within the error estimates obtained, the old {\em EKS98} parametrization is found to be fully consistent with the present analysis, with no essential difference in terms of $\chi^2$ either. We also determine separate uncertainty bands for the nuclear gluon and sea quark modifications in the large-$x$ region where they are not stringently constrained by the available data. Comparison with other global analyses is shown and uncertainties demonstrated. Finally, we show that RHIC-BRAHMS data for inclusive hadron production in d+Au collisions lend support for a stronger gluon shadowing at $x<0.01$ and also that fairly large changes in the gluon modifications do not rapidly deteriorate the goodness of the overall fits, as long as the initial gluon modifications in the region $x\sim 0.02-0.04$ remain small. |
1711.03925 | Wolfgang Lucha | Wolfgang Lucha, Dmitri Melikhov, Hagop Sazdjian | Constraints from the $1/N_{\rm c}$ Expansion on Properties of Exotic
Tetraquark Mesons | 4 pages, 2 figures, contributed to "XVII International Conference on
Hadron Spectroscopy and Structure - Hadron2017" (25 - 29 September 2017,
Salamanca, Spain) | PoS Hadron2017 (2017) 233 | null | HEPHY-PUB 995/17 (2017) | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Scrutinizing the scattering of ordinary mesons in the limiting case of the
number of colour degrees of freedom $N_{\rm c}$ of quantum chromodynamics
approaching infinity, we formulate Feynman-diagram selection criteria and from
these deduce rigorous self-consistency conditions for the manifestation of a
tetraquark, a two-quark-two-antiquark bound state, as a pole in the
corresponding amplitudes. Our constraints bear rather far-reaching
consequences: In particular, all flavour-exotic tetraquarks, composed of four
(anti)quarks of disparate flavour, must come in, at least, two variants
differing in (and thus readily identifiable by) the large-$N_{\rm c}$ behaviour
of their couplings to two ordinary mesons. Quite generally, irrespective of
their flavour composition, all tetraquarks prove to be narrow. Their decay
rates behave, for large $N_{\rm c},$ like $1/N_{\rm c}^2$ and thus decrease
faster than those of ordinary mesons.
| [
{
"created": "Fri, 10 Nov 2017 17:22:30 GMT",
"version": "v1"
}
] | 2018-02-20 | [
[
"Lucha",
"Wolfgang",
""
],
[
"Melikhov",
"Dmitri",
""
],
[
"Sazdjian",
"Hagop",
""
]
] | Scrutinizing the scattering of ordinary mesons in the limiting case of the number of colour degrees of freedom $N_{\rm c}$ of quantum chromodynamics approaching infinity, we formulate Feynman-diagram selection criteria and from these deduce rigorous self-consistency conditions for the manifestation of a tetraquark, a two-quark-two-antiquark bound state, as a pole in the corresponding amplitudes. Our constraints bear rather far-reaching consequences: In particular, all flavour-exotic tetraquarks, composed of four (anti)quarks of disparate flavour, must come in, at least, two variants differing in (and thus readily identifiable by) the large-$N_{\rm c}$ behaviour of their couplings to two ordinary mesons. Quite generally, irrespective of their flavour composition, all tetraquarks prove to be narrow. Their decay rates behave, for large $N_{\rm c},$ like $1/N_{\rm c}^2$ and thus decrease faster than those of ordinary mesons. |
2303.11352 | Lucien Heurtier | Robert Heighton, Lucien Heurtier and Michael Spannowsky | Hunting for Neutral Leptons with Ultra-High-Energy Cosmic Rays | 14 pages, 11 figures. Manuscript updated with additional references | null | null | null | hep-ph astro-ph.HE | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Next-generation large-volume detectors, such as GRAND, POEMMA, Trinity,
TAROGE-M, TAMBO, or PUEO, have been designed to search for ultra-high-energy
cosmic rays (UHECRs) with unprecedented sensitivity. We propose to use these
detectors to search for new physics beyond the Standard Model (BSM). By
considering the simple case of a right-handed neutrino that mixes exclusively
with the active $\tau$ neutrino, we demonstrate that the existence of new
physics can increase the probability for UHECRs to propagate through the Earth
and produce extensive air showers that will be measurable soon. We compare the
fluxes of such showers that would arise from various diffuse and transient
sources of high-energy neutrinos, both in the Standard Model and in the
presence of a right-handed neutrino. We show that detecting events with
emergence angles $\gtrsim 10$ deg is promising to probe the existence of BSM
physics, and we study the sensitivity of GRAND and POEMMA to do so. In
particular, we show that the hypothesis of a right-handed neutrino with a mass
of $\mathcal O(1-16)$ GeV may be probed in the future for mixing angles as
small as $|U_{\tau N}|^2 \gtrsim 10^{-7}$, thus competing with existing and
projected experimental limits.
| [
{
"created": "Mon, 20 Mar 2023 18:00:01 GMT",
"version": "v1"
},
{
"created": "Thu, 27 Apr 2023 11:49:50 GMT",
"version": "v2"
}
] | 2023-04-28 | [
[
"Heighton",
"Robert",
""
],
[
"Heurtier",
"Lucien",
""
],
[
"Spannowsky",
"Michael",
""
]
] | Next-generation large-volume detectors, such as GRAND, POEMMA, Trinity, TAROGE-M, TAMBO, or PUEO, have been designed to search for ultra-high-energy cosmic rays (UHECRs) with unprecedented sensitivity. We propose to use these detectors to search for new physics beyond the Standard Model (BSM). By considering the simple case of a right-handed neutrino that mixes exclusively with the active $\tau$ neutrino, we demonstrate that the existence of new physics can increase the probability for UHECRs to propagate through the Earth and produce extensive air showers that will be measurable soon. We compare the fluxes of such showers that would arise from various diffuse and transient sources of high-energy neutrinos, both in the Standard Model and in the presence of a right-handed neutrino. We show that detecting events with emergence angles $\gtrsim 10$ deg is promising to probe the existence of BSM physics, and we study the sensitivity of GRAND and POEMMA to do so. In particular, we show that the hypothesis of a right-handed neutrino with a mass of $\mathcal O(1-16)$ GeV may be probed in the future for mixing angles as small as $|U_{\tau N}|^2 \gtrsim 10^{-7}$, thus competing with existing and projected experimental limits. |
2102.05818 | Boris Blankleider | B. Blankleider and A. N. Kvinikhidze | Comment on "$\sigma$-meson: Four-quark versus two-quark components and
decay width in a Bethe-Salpeter approach" | 4 pages, 2 figures, misprints in Eq.(5) and Eq.(7) corrected | null | null | null | hep-ph nucl-th | http://creativecommons.org/licenses/by/4.0/ | In a recent paper by N. Santowsky et al. [Phys. Rev. D 102, 056014 (2020)],
covariant coupled equations were derived to describe a tetraquark in terms of a
mix of four-quark states $2q 2\bar{q}$ and two-quark states $q\bar{q}$. These
equations were expressed in terms of vertices describing the disintegration of
a tetraquark into identical two-meson states, into a diquark-antidiquark pair,
and into a quark-antiquark pair. We show that these equations are inconsistent
as they imply a $q\bar{q}$ Bethe-Salpeter kernel that is $q\bar{q}$-reducible.
| [
{
"created": "Thu, 11 Feb 2021 02:49:19 GMT",
"version": "v1"
},
{
"created": "Sat, 27 Feb 2021 20:51:52 GMT",
"version": "v2"
}
] | 2021-03-02 | [
[
"Blankleider",
"B.",
""
],
[
"Kvinikhidze",
"A. N.",
""
]
] | In a recent paper by N. Santowsky et al. [Phys. Rev. D 102, 056014 (2020)], covariant coupled equations were derived to describe a tetraquark in terms of a mix of four-quark states $2q 2\bar{q}$ and two-quark states $q\bar{q}$. These equations were expressed in terms of vertices describing the disintegration of a tetraquark into identical two-meson states, into a diquark-antidiquark pair, and into a quark-antiquark pair. We show that these equations are inconsistent as they imply a $q\bar{q}$ Bethe-Salpeter kernel that is $q\bar{q}$-reducible. |
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