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|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
hep-ph/0411332 | John Collins | John C. Collins, Xiaomin Zu | Initial State Parton Showers Beyond Leading Order | 45 pages | JHEP0503:059,2005 | 10.1088/1126-6708/2005/03/059 | null | hep-ph | null | We derive a new method for initial-state collinear showering in Monte-Carlo
event generators which is based on the use of unintegrated parton correlation
functions. Combined with a previously derived method for final-state showering,
the method solves the problem of treating both the hard scattering and the
evolution kernels to be used in arbitrarily non-leading order. Although we only
treat collinear showering, so that further extensions are needed for QCD, we
have discovered several new results: (1) It is better to generate exact parton
kinematics in the hard scattering rather than with the subsequent parton
showering, and similarly at each step of the showering. (2) Parton showering is
then done conditionally on the exact energy-momentum of the initiating parton.
(3) We obtain a factorization for structure functions in terms of parton
correlation functions so that parton kinematics can be treated exactly from the
beginning. (4) We obtain two factorization properties for parton correlation
functions, one in terms of ordinary parton densities and one, suitable for
event generation, in terms of parton correlation functions themselves.
| [
{
"created": "Wed, 24 Nov 2004 23:49:28 GMT",
"version": "v1"
},
{
"created": "Tue, 12 Apr 2005 15:13:47 GMT",
"version": "v2"
}
] | 2008-11-26 | [
[
"Collins",
"John C.",
""
],
[
"Zu",
"Xiaomin",
""
]
] | We derive a new method for initial-state collinear showering in Monte-Carlo event generators which is based on the use of unintegrated parton correlation functions. Combined with a previously derived method for final-state showering, the method solves the problem of treating both the hard scattering and the evolution kernels to be used in arbitrarily non-leading order. Although we only treat collinear showering, so that further extensions are needed for QCD, we have discovered several new results: (1) It is better to generate exact parton kinematics in the hard scattering rather than with the subsequent parton showering, and similarly at each step of the showering. (2) Parton showering is then done conditionally on the exact energy-momentum of the initiating parton. (3) We obtain a factorization for structure functions in terms of parton correlation functions so that parton kinematics can be treated exactly from the beginning. (4) We obtain two factorization properties for parton correlation functions, one in terms of ordinary parton densities and one, suitable for event generation, in terms of parton correlation functions themselves. |
hep-ph/0102187 | Koichi Hamaguchi | Masaaki Fujii, K. Hamaguchi, and T. Yanagida | Reheating-temperature independence of cosmological baryon asymmetry in
Affleck-Dine leptogenesis | 22 pages, LaTeX, 9 eps figures | Phys.Rev. D63 (2001) 123513 | 10.1103/PhysRevD.63.123513 | null | hep-ph | null | In this paper we point out that the cosmological baryon asymmetry in our
universe is generated almost independently of the reheating temperature $T_R$
in Affleck-Dine leptogenesis and it is determined mainly by the mass of the
lightest neutrino, $m_{\nu_1}$, in a wide range of the reheating temperature
$T_R\simeq 10^5$--$10^{12}$ GeV. The present baryon asymmetry predicts the
$m_{\nu_1}$ in a narrow region, $m_{\nu_1}\simeq (0.3$--$1)\times 10^{-9}$ eV.
Such a small mass of the lightest neutrino leads to a high predictability on
the mass parameter $m_{\nu_e \nu_e}$ contributing to the neutrinoless double
beta decay. We also propose an explicit model in which such an ultralight
neutrino can be naturally obtained.
| [
{
"created": "Thu, 15 Feb 2001 14:02:14 GMT",
"version": "v1"
}
] | 2009-11-07 | [
[
"Fujii",
"Masaaki",
""
],
[
"Hamaguchi",
"K.",
""
],
[
"Yanagida",
"T.",
""
]
] | In this paper we point out that the cosmological baryon asymmetry in our universe is generated almost independently of the reheating temperature $T_R$ in Affleck-Dine leptogenesis and it is determined mainly by the mass of the lightest neutrino, $m_{\nu_1}$, in a wide range of the reheating temperature $T_R\simeq 10^5$--$10^{12}$ GeV. The present baryon asymmetry predicts the $m_{\nu_1}$ in a narrow region, $m_{\nu_1}\simeq (0.3$--$1)\times 10^{-9}$ eV. Such a small mass of the lightest neutrino leads to a high predictability on the mass parameter $m_{\nu_e \nu_e}$ contributing to the neutrinoless double beta decay. We also propose an explicit model in which such an ultralight neutrino can be naturally obtained. |
1111.3506 | Masaki Asano | Masaki Asano, Takeo Moroi, Ryosuke Sato, Tsutomu T. Yanagida | Focus Point Assisted by Right-Handed Neutrinos | 9 pages, 2 figures | null | 10.1016/j.physletb.2012.01.030 | UT-11-37; IPMU-11-0187 | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The large hadron collider experiments have now reached the focus point region
in which the scalar masses are multi-TeV. We study the parameter region of the
focus point scenario which may realize a natural electroweak symmetry breaking
avoiding serious fine tuning. We show that the region with a mild tuning of 3-5
% level is expanded by introducing right-handed neutrinos in the framework of
the seesaw scenario. We discuss the prediction of the Higgs mass, bounds on the
squark and gluino masses, and the relic density of the lightest neutralino in
such a parameter region.
| [
{
"created": "Tue, 15 Nov 2011 11:37:15 GMT",
"version": "v1"
}
] | 2015-06-03 | [
[
"Asano",
"Masaki",
""
],
[
"Moroi",
"Takeo",
""
],
[
"Sato",
"Ryosuke",
""
],
[
"Yanagida",
"Tsutomu T.",
""
]
] | The large hadron collider experiments have now reached the focus point region in which the scalar masses are multi-TeV. We study the parameter region of the focus point scenario which may realize a natural electroweak symmetry breaking avoiding serious fine tuning. We show that the region with a mild tuning of 3-5 % level is expanded by introducing right-handed neutrinos in the framework of the seesaw scenario. We discuss the prediction of the Higgs mass, bounds on the squark and gluino masses, and the relic density of the lightest neutralino in such a parameter region. |
hep-ph/9405314 | Achim Wambach | F. E. Close, A. Wambach | Flavour Dependence of Form Factors in Heavy Meson Decays | 10 pages, 3 figures (ps file available upon request), RAL-94-041,
OUTP-94 09P | Phys.Lett.B348:207-212,1995 | 10.1016/0370-2693(95)00118-5 | null | hep-ph | null | Recently we have shown that due account of Wigner spin rotations is needed to
match the ISGW model consistently onto HQET. We now discuss the flavour
dependence of this procedure. We find that for finite mass ``heavy'' quark the
universal function $\xi(y=1) \approx 1$ but the slope is proportional to the
energy of the spectator quarks, and ratios of form factors are corrected in a
way that QCD sum rules seem to require. Predictions for heavy quarks, such as
in $B_c \rightarrow \psi(\eta_c)$ and to mixed systems, such as $D\rightarrow
K$ and $B \rightarrow \pi$ show a systematic mass dependence that may be
confronted with data.
| [
{
"created": "Wed, 18 May 1994 08:33:47 GMT",
"version": "v1"
}
] | 2010-11-01 | [
[
"Close",
"F. E.",
""
],
[
"Wambach",
"A.",
""
]
] | Recently we have shown that due account of Wigner spin rotations is needed to match the ISGW model consistently onto HQET. We now discuss the flavour dependence of this procedure. We find that for finite mass ``heavy'' quark the universal function $\xi(y=1) \approx 1$ but the slope is proportional to the energy of the spectator quarks, and ratios of form factors are corrected in a way that QCD sum rules seem to require. Predictions for heavy quarks, such as in $B_c \rightarrow \psi(\eta_c)$ and to mixed systems, such as $D\rightarrow K$ and $B \rightarrow \pi$ show a systematic mass dependence that may be confronted with data. |
1406.1647 | Zbigniew Was | T. Przedzinski, E. Richter-Was, Z. Was | TauSpinner: a tool for simulating CP effects in H to tau tau decays at
LHC | 1+18 pages,4 figures | null | 10.1140/epjc/s10052-014-3177-8 | IFJPAN-IV-2014-9 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this paper, we discuss application of the TauSpinner package as a
simulation tool for measuring the CP state of the newly discovered Higgs boson
using the transverse spin correlations in the H to tau tau decay channel. We
discuss application for its main background Z/gamma* to tau tau as well. The
TauSpinner package allows one to add, with the help of weights, transverse spin
correlations corresponding to any mixture of scalar/pseudoscalar state, on
already existing events using information from the kinematics of outgoing tau
leptons and their decay products only. This procedure can be used when
polarimetric vectors of the taus decays and density matrix for tau-pair
production are not stored with the event sample.
We concentrate on the well-defined effects for the Higgs (or Higgs-like
scalar) decays, which are physically separated from the production processes.
TauSpinner also allows to reintroduce (or remove) spin correlations to events
from Drell-Yan Z/gamma* to tau tau process, the main background for the Higgs
parity observables, again with the help of weights only.
From the literature, we recall well-established observables, developed for
measuring the CP of the Higgs, and use them as benchmarks for illustrating
applications of the TauSpinner package. We also include a description of the
code and prepared testing examples.
| [
{
"created": "Fri, 6 Jun 2014 11:21:55 GMT",
"version": "v1"
}
] | 2015-06-19 | [
[
"Przedzinski",
"T.",
""
],
[
"Richter-Was",
"E.",
""
],
[
"Was",
"Z.",
""
]
] | In this paper, we discuss application of the TauSpinner package as a simulation tool for measuring the CP state of the newly discovered Higgs boson using the transverse spin correlations in the H to tau tau decay channel. We discuss application for its main background Z/gamma* to tau tau as well. The TauSpinner package allows one to add, with the help of weights, transverse spin correlations corresponding to any mixture of scalar/pseudoscalar state, on already existing events using information from the kinematics of outgoing tau leptons and their decay products only. This procedure can be used when polarimetric vectors of the taus decays and density matrix for tau-pair production are not stored with the event sample. We concentrate on the well-defined effects for the Higgs (or Higgs-like scalar) decays, which are physically separated from the production processes. TauSpinner also allows to reintroduce (or remove) spin correlations to events from Drell-Yan Z/gamma* to tau tau process, the main background for the Higgs parity observables, again with the help of weights only. From the literature, we recall well-established observables, developed for measuring the CP of the Higgs, and use them as benchmarks for illustrating applications of the TauSpinner package. We also include a description of the code and prepared testing examples. |
1907.04338 | Martin Gabelmann | Martin Gabelmann, Margarete M. M\"uhlleitner, Florian Staub | The Singlet Extended Standard Model in the Context of Split
Supersymmetry | 11 pages, 9 figures | Phys. Rev. D 100, 075026 (2019) | 10.1103/PhysRevD.100.075026 | P3H-19-018, KA-TP-14-2019 | hep-ph | http://creativecommons.org/licenses/by/4.0/ | We consider a low-energy effective theory of the next-to-minimal
supersymmetric Standard Model by decoupling all scalar states except one Higgs
doublet and the complex gauge singlet. The mass spectrum of the resulting
singlet-extended Standard Model is calculated from two different perspectives:
1) using a matching of the scalar sectors at next-to-leading order; 2) using
the simplified-model approach of calculating the masses in the effective theory
at fixed order at the weak scale ignoring any connection to the full theory.
Significant deviations between the two methods are found not only in the scalar
sector, but also properties of the additional fermions can be very different.
Thus, only a small part of the parameter space of the simplified model can be
embedded in a well motivated SUSY framework.
| [
{
"created": "Tue, 9 Jul 2019 18:00:07 GMT",
"version": "v1"
},
{
"created": "Tue, 29 Oct 2019 07:48:26 GMT",
"version": "v2"
}
] | 2019-10-30 | [
[
"Gabelmann",
"Martin",
""
],
[
"Mühlleitner",
"Margarete M.",
""
],
[
"Staub",
"Florian",
""
]
] | We consider a low-energy effective theory of the next-to-minimal supersymmetric Standard Model by decoupling all scalar states except one Higgs doublet and the complex gauge singlet. The mass spectrum of the resulting singlet-extended Standard Model is calculated from two different perspectives: 1) using a matching of the scalar sectors at next-to-leading order; 2) using the simplified-model approach of calculating the masses in the effective theory at fixed order at the weak scale ignoring any connection to the full theory. Significant deviations between the two methods are found not only in the scalar sector, but also properties of the additional fermions can be very different. Thus, only a small part of the parameter space of the simplified model can be embedded in a well motivated SUSY framework. |
hep-ph/0208072 | Fornengo Nicolao | N. Fornengo (1), A. Riotto (2) and S. Scopel (1) ((1) U. of Torino and
INFN-Torino, (2) INFN-Padova) | Supersymmetric Dark Matter and the Reheating Temperature of the Universe | 21 pages, 5 figures, typeset with ReVTeX4. The paper may also be
found at http://www.to.infn.it/~fornengo/papers/reheating.ps.gz | Phys.Rev. D67 (2003) 023514 | 10.1103/PhysRevD.67.023514 | DFTT 24/2002 | hep-ph astro-ph hep-ex | null | Since the thermal history of the Universe is unknown before the epoch of
primordial nucleosynthesis, the largest temperature of the radiation dominated
phase (the reheating temperature) might have been as low as 1 MeV. We perform a
quantitative study of supersymmetric dark matter relic abundance in
cosmological scenarios with low reheating temperature. We show that, for values
of the reheating temperature smaller than about 30 GeV, the domains of the
supergravity parameter space which are compatible with the hypothesis that dark
matter is composed by neutralinos are largely enhanced. We also find a lower
bound on the reheating temperature: if the latter is smaller than about 1 GeV
neutralinos cannot be efficiently produced in the early Universe and then they
are not able to explain the present amount of dark matter.
| [
{
"created": "Wed, 7 Aug 2002 15:38:57 GMT",
"version": "v1"
}
] | 2009-11-07 | [
[
"Fornengo",
"N.",
""
],
[
"Riotto",
"A.",
""
],
[
"Scopel",
"S.",
""
]
] | Since the thermal history of the Universe is unknown before the epoch of primordial nucleosynthesis, the largest temperature of the radiation dominated phase (the reheating temperature) might have been as low as 1 MeV. We perform a quantitative study of supersymmetric dark matter relic abundance in cosmological scenarios with low reheating temperature. We show that, for values of the reheating temperature smaller than about 30 GeV, the domains of the supergravity parameter space which are compatible with the hypothesis that dark matter is composed by neutralinos are largely enhanced. We also find a lower bound on the reheating temperature: if the latter is smaller than about 1 GeV neutralinos cannot be efficiently produced in the early Universe and then they are not able to explain the present amount of dark matter. |
1009.2965 | Konrad Tywoniuk | Yacine Mehtar-Tani, Carlos A. Salgado and Konrad Tywoniuk | Antiangular Ordering of Gluon Radiation in QCD Media | 4 pages, 2 figures; v2. a number of minor improvements, figures
updated, accepted for publication in PRL | Phys.Rev.Lett.106:122002,2011 | 10.1103/PhysRevLett.106.122002 | null | hep-ph nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We investigate angular and energy distributions of medium-induced gluon
emission off a quark-antiquark antenna in the framework of perturbative QCD as
an attempt toward understanding, from first principles, jet evolution inside
the quark-gluon plasma. In-medium color coherence between emitters, neglected
in all previous calculations, leads to a novel mechanism of soft-gluon
radiation. The structure of the corresponding spectrum, in contrast with known
medium-induced radiation, retains some properties of the vacuum case; in
particular, it exhibits a soft divergency. However, as opposed to the vacuum,
the collinear singularity is regulated by the pair opening angle, leading to a
strict angular separation between vacuum and medium-induced radiation, denoted
as antiangular ordering. We comment on the possible consequences of this new
contribution for jet observables in heavy-ion collisions.
| [
{
"created": "Wed, 15 Sep 2010 16:28:49 GMT",
"version": "v1"
},
{
"created": "Wed, 16 Mar 2011 17:00:10 GMT",
"version": "v2"
}
] | 2011-04-05 | [
[
"Mehtar-Tani",
"Yacine",
""
],
[
"Salgado",
"Carlos A.",
""
],
[
"Tywoniuk",
"Konrad",
""
]
] | We investigate angular and energy distributions of medium-induced gluon emission off a quark-antiquark antenna in the framework of perturbative QCD as an attempt toward understanding, from first principles, jet evolution inside the quark-gluon plasma. In-medium color coherence between emitters, neglected in all previous calculations, leads to a novel mechanism of soft-gluon radiation. The structure of the corresponding spectrum, in contrast with known medium-induced radiation, retains some properties of the vacuum case; in particular, it exhibits a soft divergency. However, as opposed to the vacuum, the collinear singularity is regulated by the pair opening angle, leading to a strict angular separation between vacuum and medium-induced radiation, denoted as antiangular ordering. We comment on the possible consequences of this new contribution for jet observables in heavy-ion collisions. |
hep-ph/0009272 | Grunberg | Georges Grunberg | Fixing the conformal window in QCD | 10 pages, 1 figure, extended version of a talk given at the
QCDNET2000 meeting, Paris, September 11-14 2000; main new material added is
evidence for negative ultraviolet fixed point in QCD | Phys.Rev. D65 (2002) 021701 | 10.1103/PhysRevD.65.021701 | CPTh/PC 087.0900 | hep-ph hep-th | null | A physical characterization of Landau singularities is emphasized, which
should trace the lower boundary N_f^* of the conformal window in QCD and
supersymmetric QCD. A natural way to disentangle ``perturbative'' from
``non-perturbative'' contributions to amplitudes below N_f^* is suggested.
Assuming an infrared fixed point persists in the perturbative part of the QCD
coupling even below N_f^* leads to the condition \gamma(N_f^*)=1, where \gamma
is the critical exponent. Using the Banks-Zaks expansion, one gets 4<N_f^*<6.
This result is incompatible with the existence of an analogue of Seiberg
duality in QCD. The presence of a negative ultraviolet fixed point is required
both in QCD and in supersymmetric QCD to preserve causality within the
conformal window. Evidence for the existence of such a fixed point in QCD is
provided.
| [
{
"created": "Fri, 22 Sep 2000 18:56:40 GMT",
"version": "v1"
},
{
"created": "Thu, 16 Nov 2000 15:01:24 GMT",
"version": "v2"
}
] | 2009-10-31 | [
[
"Grunberg",
"Georges",
""
]
] | A physical characterization of Landau singularities is emphasized, which should trace the lower boundary N_f^* of the conformal window in QCD and supersymmetric QCD. A natural way to disentangle ``perturbative'' from ``non-perturbative'' contributions to amplitudes below N_f^* is suggested. Assuming an infrared fixed point persists in the perturbative part of the QCD coupling even below N_f^* leads to the condition \gamma(N_f^*)=1, where \gamma is the critical exponent. Using the Banks-Zaks expansion, one gets 4<N_f^*<6. This result is incompatible with the existence of an analogue of Seiberg duality in QCD. The presence of a negative ultraviolet fixed point is required both in QCD and in supersymmetric QCD to preserve causality within the conformal window. Evidence for the existence of such a fixed point in QCD is provided. |
1110.2446 | Anna Kulesza | W. Beenakker, S. Brensing, M. Kr\"amer, A. Kulesza, E. Laenen and I.
Niessen | NNLL resummation for squark-antisquark pair production at the LHC | 22 pages, 5 figures | null | 10.1007/JHEP01(2012)076 | DESY 11-175, ITP-UU-11/36, ITFA 11-14, NIKHEF/2011-027, TTK-11-47 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We consider the resummation of soft gluon emission for squark-antisquark
pair-production at the LHC at next-to-next-to-leading-logarithmic (NNLL)
accuracy in the framework of the minimal supersymmetric standard model. We
present the analytical ingredients needed for the calculation and provide
numerical predictions for the LHC at centre-of-mass energies of 7 and 14 TeV.
We find a significant reduction in the scale uncertainty and a considerable
increase in the prediction of the total cross section. Compared to the
next-to-leading order prediction, the corrections increase the cross section by
up to 30% for 1.5 TeV squarks at a centre-of-mass energy of 7 TeV.
| [
{
"created": "Tue, 11 Oct 2011 17:33:16 GMT",
"version": "v1"
}
] | 2015-05-30 | [
[
"Beenakker",
"W.",
""
],
[
"Brensing",
"S.",
""
],
[
"Krämer",
"M.",
""
],
[
"Kulesza",
"A.",
""
],
[
"Laenen",
"E.",
""
],
[
"Niessen",
"I.",
""
]
] | We consider the resummation of soft gluon emission for squark-antisquark pair-production at the LHC at next-to-next-to-leading-logarithmic (NNLL) accuracy in the framework of the minimal supersymmetric standard model. We present the analytical ingredients needed for the calculation and provide numerical predictions for the LHC at centre-of-mass energies of 7 and 14 TeV. We find a significant reduction in the scale uncertainty and a considerable increase in the prediction of the total cross section. Compared to the next-to-leading order prediction, the corrections increase the cross section by up to 30% for 1.5 TeV squarks at a centre-of-mass energy of 7 TeV. |
1407.0415 | Beranger Dumont | Beranger Dumont | Higgs coupling measurements and impact on the MSSM | 6 pages, 4 figures. Presented at the XXII. International Workshop on
Deep-Inelastic Scattering and Related Subjects (DIS 2014), Warsaw, Poland, 28
April - 2 May 2014. To appear in the proceedings | PoS(DIS2014)128 | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Run I of the LHC has not revealed any sign of new physics beyond the Standard
Model (BSM). However, the discovery of an SM-like Higgs boson with mass around
125 GeV opens up new possibilities for probing various BSM scenarios with
enlarged Higgs sectors and/or new particles affecting the loop-induced
processes or opening new decay modes. We will present how we derive constraints
on new physics from the Higgs measurements performed by the ATLAS and CMS
collaborations. The impact of these measurements will then be assessed in the
context of the general phenomenological Minimal Supersymmetric Standard Model
(MSSM) and in the MSSM with a light neutralino as a dark matter candidate.
| [
{
"created": "Tue, 1 Jul 2014 21:48:35 GMT",
"version": "v1"
}
] | 2014-07-03 | [
[
"Dumont",
"Beranger",
""
]
] | Run I of the LHC has not revealed any sign of new physics beyond the Standard Model (BSM). However, the discovery of an SM-like Higgs boson with mass around 125 GeV opens up new possibilities for probing various BSM scenarios with enlarged Higgs sectors and/or new particles affecting the loop-induced processes or opening new decay modes. We will present how we derive constraints on new physics from the Higgs measurements performed by the ATLAS and CMS collaborations. The impact of these measurements will then be assessed in the context of the general phenomenological Minimal Supersymmetric Standard Model (MSSM) and in the MSSM with a light neutralino as a dark matter candidate. |
hep-ph/0207282 | Melissinos | A.C. Melissinos | A "Running" Gravitational Constant? | 4 pages | null | null | null | hep-ph | null | If the gravitational interaction is unified with the electroweak and strong
interactions at a mass M=10^15 GeV, the evolution of Newton's constant must
differ from its classical (general relativistic) form. We can model such
behavior by introducing an ad hoc dependence on ln(s/4m^2) where s is the usual
cm energy between two protons. We can then predict the observable effects for
relativistic collisions (sqrt(s)~1.4x10^4 GeV) as well as for the case of low
velocity motion (beta^2~10^-5)
| [
{
"created": "Tue, 23 Jul 2002 14:12:46 GMT",
"version": "v1"
},
{
"created": "Tue, 23 Jul 2002 20:38:44 GMT",
"version": "v2"
}
] | 2007-05-23 | [
[
"Melissinos",
"A. C.",
""
]
] | If the gravitational interaction is unified with the electroweak and strong interactions at a mass M=10^15 GeV, the evolution of Newton's constant must differ from its classical (general relativistic) form. We can model such behavior by introducing an ad hoc dependence on ln(s/4m^2) where s is the usual cm energy between two protons. We can then predict the observable effects for relativistic collisions (sqrt(s)~1.4x10^4 GeV) as well as for the case of low velocity motion (beta^2~10^-5) |
2311.15422 | Neda Darvishi | Neda Darvishi, Yining Wang and Jiang-Hao Yu | Automated Ring-Diagram Framework for Classifying CP Invariants | 14 pages, 4 figures and 4 tables | Phys. Rev. D 108, 115030 - 2023 | 10.1103/PhysRevD.108.115030 | null | hep-ph hep-th | http://creativecommons.org/publicdomain/zero/1.0/ | In this study, we introduce a transformative, automated framework for
classifying basis invariants in generic field theories. Utilising a novel
ring-diagram methodology accompanied by the well-known Cayley-Hamilton theorem,
our approach uniquely enables the identification of basic invariants and their
CP-property characterisation. Critically, our framework also unveils previously
concealed attributes of established techniques reliant on the
Hilbert-Poincar\'e series and its associated Plethystic logarithm. This
paradigm shift has broad implications for the deeper understanding and more
accurate classification of CP invariants in generic field theories.
| [
{
"created": "Sun, 26 Nov 2023 21:10:57 GMT",
"version": "v1"
},
{
"created": "Sat, 30 Dec 2023 21:15:54 GMT",
"version": "v2"
}
] | 2024-01-02 | [
[
"Darvishi",
"Neda",
""
],
[
"Wang",
"Yining",
""
],
[
"Yu",
"Jiang-Hao",
""
]
] | In this study, we introduce a transformative, automated framework for classifying basis invariants in generic field theories. Utilising a novel ring-diagram methodology accompanied by the well-known Cayley-Hamilton theorem, our approach uniquely enables the identification of basic invariants and their CP-property characterisation. Critically, our framework also unveils previously concealed attributes of established techniques reliant on the Hilbert-Poincar\'e series and its associated Plethystic logarithm. This paradigm shift has broad implications for the deeper understanding and more accurate classification of CP invariants in generic field theories. |
hep-ph/9809383 | Nicholas Petropoulos | Nicholas Petropoulos | Thermal effective potential of the linear sigma model | 4 pages revtex, 5 eps figures, axodraw.sty, poster presented in the
5th International Workshop on Thermal Field Theories, Regensburg, Germany | null | null | null | hep-ph | null | We have attempted an approach to the chiral phase transition of QCD using the
linear sigma model as an effective theory. In order to get some insight into
how the phase transition could proceed, we have calculated the finite
temperature effective potential of this model in the Hartree and large N
approximations using the Cornwall-Jackiw-Tomboulis formalism of composite
operators.
| [
{
"created": "Mon, 14 Sep 1998 21:16:25 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Petropoulos",
"Nicholas",
""
]
] | We have attempted an approach to the chiral phase transition of QCD using the linear sigma model as an effective theory. In order to get some insight into how the phase transition could proceed, we have calculated the finite temperature effective potential of this model in the Hartree and large N approximations using the Cornwall-Jackiw-Tomboulis formalism of composite operators. |
2210.11011 | Alexander Ritter | Alexander C. Ritter, Raymond R. Volkas | Exploring the cosmological dark matter coincidence using infrared fixed
points | 13 pages, 11 figures, 2 tables | null | 10.1103/PhysRevD.107.015029 | null | hep-ph | http://creativecommons.org/licenses/by/4.0/ | The asymmetric dark matter (ADM) paradigm is motivated by the apparent
coincidence between the cosmological mass densities of visible and dark matter,
$\Omega_\mathrm{DM} \simeq 5\Omega_\mathrm{VM}$. However, most ADM models only
relate the number densities of visible and dark matter, and do not motivate the
similarity in their particle masses. One exception is a framework introduced by
Bai and Schwaller, where the dark matter is a confined state of a dark QCD-like
gauge group, and the confinement scales of visible and dark QCD are related by
a dynamical mechanism utilising infrared fixed points of the two gauge
couplings. We build upon this framework by properly implementing the dependence
of the results on the initial conditions for the gauge couplings in the UV. We
then reassess the ability of this framework to naturally explain the
cosmological mass density coincidence, and find a reduced number of viable
models. We identify features of the viable models that allow them to naturally
relate the masses of the dark baryon and the proton while also avoiding
collider constraints on the new particle content introduced.
| [
{
"created": "Thu, 20 Oct 2022 04:35:09 GMT",
"version": "v1"
}
] | 2023-02-15 | [
[
"Ritter",
"Alexander C.",
""
],
[
"Volkas",
"Raymond R.",
""
]
] | The asymmetric dark matter (ADM) paradigm is motivated by the apparent coincidence between the cosmological mass densities of visible and dark matter, $\Omega_\mathrm{DM} \simeq 5\Omega_\mathrm{VM}$. However, most ADM models only relate the number densities of visible and dark matter, and do not motivate the similarity in their particle masses. One exception is a framework introduced by Bai and Schwaller, where the dark matter is a confined state of a dark QCD-like gauge group, and the confinement scales of visible and dark QCD are related by a dynamical mechanism utilising infrared fixed points of the two gauge couplings. We build upon this framework by properly implementing the dependence of the results on the initial conditions for the gauge couplings in the UV. We then reassess the ability of this framework to naturally explain the cosmological mass density coincidence, and find a reduced number of viable models. We identify features of the viable models that allow them to naturally relate the masses of the dark baryon and the proton while also avoiding collider constraints on the new particle content introduced. |
1010.4528 | A. M. Fedotov | N.V. Elkina, A.M. Fedotov, I.Yu. Kostyukov, M.V. Legkov, N.B.
Narozhny, E.N. Nerush, and H. Ruhl | QED cascades induced by circularly polarized laser fields | 13 pages, 10 figures | Phys.Rev.ST Accel.Beams 14:054401,2011 | 10.1103/PhysRevSTAB.14.054401 | null | hep-ph physics.acc-ph physics.comp-ph physics.optics physics.plasm-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The results of Monte-Carlo simulations of electron-positron-photon cascades
initiated by slow electrons in circularly polarized fields of ultra-high
strength are presented and discussed. Our results confirm previous qualitative
estimations [A.M. Fedotov, et al., PRL 105, 080402 (2010)] of the formation of
cascades. This sort of cascades has revealed the new property of the
restoration of energy and dynamical quantum parameter due to the acceleration
of electrons and positrons by the field and may become a dominating feature of
laser-matter interactions at ultra-high intensities. Our approach incorporates
radiation friction acting on individual electrons and positrons.
| [
{
"created": "Thu, 21 Oct 2010 17:27:29 GMT",
"version": "v1"
}
] | 2011-05-23 | [
[
"Elkina",
"N. V.",
""
],
[
"Fedotov",
"A. M.",
""
],
[
"Kostyukov",
"I. Yu.",
""
],
[
"Legkov",
"M. V.",
""
],
[
"Narozhny",
"N. B.",
""
],
[
"Nerush",
"E. N.",
""
],
[
"Ruhl",
"H.",
""
]
] | The results of Monte-Carlo simulations of electron-positron-photon cascades initiated by slow electrons in circularly polarized fields of ultra-high strength are presented and discussed. Our results confirm previous qualitative estimations [A.M. Fedotov, et al., PRL 105, 080402 (2010)] of the formation of cascades. This sort of cascades has revealed the new property of the restoration of energy and dynamical quantum parameter due to the acceleration of electrons and positrons by the field and may become a dominating feature of laser-matter interactions at ultra-high intensities. Our approach incorporates radiation friction acting on individual electrons and positrons. |
hep-ph/0203010 | A. Perez-Lorenzana | Herman J. Mosquera Cuesta, Andr\'e Penna-Firme and Abdel
P\'erez-Lorenzana | Charge Asymmetry in the Brane World and Formation of Charged Black Holes | Four pages, one figure. Minor changes, conclusions remain | Phys.Rev.D67:087702,2003 | 10.1103/PhysRevD.67.087702 | null | hep-ph astro-ph gr-qc hep-th | null | In theories with an infinite extra dimension, free particles localized on the
brane can leak out to the extra space. We argue that if there were color
confinement in the bulk, electrons would be more able to escape than quarks and
than protons (which are composed states). Thus, this process generates an
electric charge asymmetry on brane matter densities. A primordial charge
asymmetry during Big Bang Nucleosynthesis era is predicted. We use current
bounds on this and on electron disappearance to constrain the parameter space
of these models. Although the generated asymmetry is generically small, it
could be particularly enhanced on large densities as in astrophysical objects,
like massive stars. We suggest the possibility that such accumulation of charge
may be linked, upon supernova collapse, to the formation of a charged Black
Hole and the generation of Gamma-Ray Bursts.
| [
{
"created": "Fri, 1 Mar 2002 19:26:34 GMT",
"version": "v1"
},
{
"created": "Mon, 17 Feb 2003 01:32:30 GMT",
"version": "v2"
}
] | 2014-11-17 | [
[
"Cuesta",
"Herman J. Mosquera",
""
],
[
"Penna-Firme",
"André",
""
],
[
"Pérez-Lorenzana",
"Abdel",
""
]
] | In theories with an infinite extra dimension, free particles localized on the brane can leak out to the extra space. We argue that if there were color confinement in the bulk, electrons would be more able to escape than quarks and than protons (which are composed states). Thus, this process generates an electric charge asymmetry on brane matter densities. A primordial charge asymmetry during Big Bang Nucleosynthesis era is predicted. We use current bounds on this and on electron disappearance to constrain the parameter space of these models. Although the generated asymmetry is generically small, it could be particularly enhanced on large densities as in astrophysical objects, like massive stars. We suggest the possibility that such accumulation of charge may be linked, upon supernova collapse, to the formation of a charged Black Hole and the generation of Gamma-Ray Bursts. |
2108.00013 | Daniele Barducci | Lukas Allwicher, Pere Arnan, Daniele Barducci, Marco Nardecchia | Perturbative unitarity constraints on generic Yukawa interactions | 50 pages, 10 figures; typos fixed, references added, matches
published version | null | 10.1007/JHEP10(2021)129 | null | hep-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study perturbative unitarity constraints on generic Yukawa interactions
where the involved fields have arbitrary quantum numbers under an $\prod_i
SU(N_i) \otimes U(1)$ group. We derive compact expressions for the bounds on
the Yukawa couplings for the cases where the fields transform under the
trivial, fundamental or adjoint representation of the various $SU(N)$ factors.
We apply our results to specific models formulated to explain the anomalous
measurements of $(g-2)_\mu$ and of the charged- and neutral-current decays of
the $B$ mesons. We show that, while these models can generally still explain
the observed experimental values, the required Yukawa couplings are pushed at
the edge of the perturbative regime.
| [
{
"created": "Fri, 30 Jul 2021 18:00:02 GMT",
"version": "v1"
},
{
"created": "Thu, 9 Sep 2021 17:22:04 GMT",
"version": "v2"
}
] | 2021-11-03 | [
[
"Allwicher",
"Lukas",
""
],
[
"Arnan",
"Pere",
""
],
[
"Barducci",
"Daniele",
""
],
[
"Nardecchia",
"Marco",
""
]
] | We study perturbative unitarity constraints on generic Yukawa interactions where the involved fields have arbitrary quantum numbers under an $\prod_i SU(N_i) \otimes U(1)$ group. We derive compact expressions for the bounds on the Yukawa couplings for the cases where the fields transform under the trivial, fundamental or adjoint representation of the various $SU(N)$ factors. We apply our results to specific models formulated to explain the anomalous measurements of $(g-2)_\mu$ and of the charged- and neutral-current decays of the $B$ mesons. We show that, while these models can generally still explain the observed experimental values, the required Yukawa couplings are pushed at the edge of the perturbative regime. |
1611.09082 | Pankaj Sharma | Stefano Moretti, Rui Santos and Pankaj Sharma | Charged Higgs Boson Searches at the LHC via Multiple $b\bar bW^\pm$
Final States | Prepared for proceedings for Charged2016, talk presented by Pankaj
Sharma | null | null | ADP16-45/T1001 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We review the prospects of the Large Hadron Collider in accessing heavy
charged Higgs boson signals in $b\bar b W^\pm$ final states, wherein the
contributing channels can be $H^+\to t\bar b$, $hW^\pm$, $HW^\pm$ and $AW^\pm$.
In particular, we devise a selection strategy which optimizes their global
yield. We consider a 2-Higgs Doublet Model Type-II and we assume as production
mode $bg\to tH^-$ + c.c., the dominant one over the range $M_{H^\pm}\ge 480$
GeV, as dictated by $b\to s\gamma$ constraints. Possibilities of detection are
found to be significant for various Run 2 energies and luminosities.
| [
{
"created": "Mon, 28 Nov 2016 11:43:20 GMT",
"version": "v1"
}
] | 2016-11-29 | [
[
"Moretti",
"Stefano",
""
],
[
"Santos",
"Rui",
""
],
[
"Sharma",
"Pankaj",
""
]
] | We review the prospects of the Large Hadron Collider in accessing heavy charged Higgs boson signals in $b\bar b W^\pm$ final states, wherein the contributing channels can be $H^+\to t\bar b$, $hW^\pm$, $HW^\pm$ and $AW^\pm$. In particular, we devise a selection strategy which optimizes their global yield. We consider a 2-Higgs Doublet Model Type-II and we assume as production mode $bg\to tH^-$ + c.c., the dominant one over the range $M_{H^\pm}\ge 480$ GeV, as dictated by $b\to s\gamma$ constraints. Possibilities of detection are found to be significant for various Run 2 energies and luminosities. |
hep-ph/0403288 | Ayres Freitas | A. Freitas (Fermilab) | Weakly coupled neutral gauge bosons at future linear colliders | 21 pp | Phys.Rev. D70 (2004) 015008 | 10.1103/PhysRevD.70.015008 | FERMILAB-Pub-04/039-T | hep-ph hep-ex | null | A weakly coupled new neutral gauge boson forms a narrow resonance that is
hard to discover directly in e+e- collisions. However, if the gauge boson mass
is below the center-of-mass energy, it can be produced through processes where
the effective energy is reduced due to initial-state radiation and
beamstrahlung. It is shown that at a high-luminosity linear collider, such a
gauge boson can be searched for with very high sensitivity, leading to a
substantial improvement compared to existing limits from the Tevatron and also
extending beyond the expected reach of the LHC in most models. If a new vector
boson is discovered either at the Tevatron Run II, the LHC or the linear
collider, its properties can be determined at the linear collider with high
precision, thus helping to reveal origin of the new boson.
| [
{
"created": "Mon, 29 Mar 2004 20:33:40 GMT",
"version": "v1"
}
] | 2009-11-10 | [
[
"Freitas",
"A.",
"",
"Fermilab"
]
] | A weakly coupled new neutral gauge boson forms a narrow resonance that is hard to discover directly in e+e- collisions. However, if the gauge boson mass is below the center-of-mass energy, it can be produced through processes where the effective energy is reduced due to initial-state radiation and beamstrahlung. It is shown that at a high-luminosity linear collider, such a gauge boson can be searched for with very high sensitivity, leading to a substantial improvement compared to existing limits from the Tevatron and also extending beyond the expected reach of the LHC in most models. If a new vector boson is discovered either at the Tevatron Run II, the LHC or the linear collider, its properties can be determined at the linear collider with high precision, thus helping to reveal origin of the new boson. |
2108.13371 | Tianbo Liu | Tianbo Liu, W. Melnitchouk, Jian-Wei Qiu, N. Sato | A new approach to semi-inclusive deep-inelastic scattering with QED and
QCD factorization | 55 pages, 23 figures, accepted for publication in J. High Energy Phys | null | 10.1007/JHEP11(2021)157 | JLAB-THY-21-3489 | hep-ph hep-ex nucl-ex nucl-th | http://creativecommons.org/licenses/by/4.0/ | We present the details of a new factorized approach to semi-inclusive
deep-inelastic scattering which treats QED and QCD radiation on equal footing,
and provides a systematically improvable approximation to the extraction of
transverse momentum dependent parton distributions. We demonstrate how the QED
contributions can be well approximated by collinear factorization, and
illustrate the application of the factorized approach to QED radiation in
inclusive scattering. For semi-inclusive processes, we show how radiation
effects prevent a well-defined "photon-nucleon" frame, forcing one to use a
two-step process to account for the radiation. We illustrate the utility of the
new method by explicit application to the spin-dependent Sivers and Collins
asymmetries.
| [
{
"created": "Mon, 30 Aug 2021 16:43:57 GMT",
"version": "v1"
},
{
"created": "Thu, 11 Nov 2021 14:12:36 GMT",
"version": "v2"
}
] | 2021-12-08 | [
[
"Liu",
"Tianbo",
""
],
[
"Melnitchouk",
"W.",
""
],
[
"Qiu",
"Jian-Wei",
""
],
[
"Sato",
"N.",
""
]
] | We present the details of a new factorized approach to semi-inclusive deep-inelastic scattering which treats QED and QCD radiation on equal footing, and provides a systematically improvable approximation to the extraction of transverse momentum dependent parton distributions. We demonstrate how the QED contributions can be well approximated by collinear factorization, and illustrate the application of the factorized approach to QED radiation in inclusive scattering. For semi-inclusive processes, we show how radiation effects prevent a well-defined "photon-nucleon" frame, forcing one to use a two-step process to account for the radiation. We illustrate the utility of the new method by explicit application to the spin-dependent Sivers and Collins asymmetries. |
hep-ph/0104217 | Sourov Roy | Dilip Kumar Ghosh, Anirban Kundu, Probir Roy, Sourov Roy | Characteristic Wino Signals in a Linear Collider from Anomaly Mediated
Supersymmetry Breaking | 25 pages, LaTeX, three PS figures and one EPS figure | Phys.Rev. D64 (2001) 115001 | 10.1103/PhysRevD.64.115001 | TIFR/TH/01-02 | hep-ph hep-ex | null | Though the minimal model of anomaly mediated supersymmetry breaking has been
significantly constrained by recent experimental and theoretical work, there
are still allowed regions of the parameter space for moderate to large values
of $\tan\beta$. We show that these regions will be comprehensively probed in a
${\sqrt s} =1$ TeV $e^+e^-$ linear collider. Diagnostic signals to this end are
studied by zeroing in on a unique and distinct feature of a large class of
models in this genre: a neutral winolike Lightest Supersymmetric Particle
closely degenerate in mass with a winolike chargino. The pair production
processes $e^+e^- \to {\tilde e}_L^\pm {\tilde e}_L^\mp$, ${\tilde e}_R^\pm
{\tilde e}_R^\mp$, ${\tilde e}_L^\pm {\tilde e}_R^\mp$, ${\tilde \nu} {\bar
{\tilde \nu}}$, $\widetilde \chi^0_1 \widetilde \chi^0_2$, $\widetilde \chi^0_2
\widetilde \chi^0_2$ are all considered at $\sqrt s = 1$ TeV corresponding to
the proposed TESLA linear collider in two natural categories of mass ordering
in the sparticle spectra. The signals analysed comprise multiple combinations
of fast charged leptons (any of which can act as the trigger) plus displaced
vertices $X_D$ (any of which can be identified by a heavy ionizing track
terminating in the detector) and/or associated soft pions with characteristic
momentum distributions.
| [
{
"created": "Sun, 22 Apr 2001 13:00:01 GMT",
"version": "v1"
}
] | 2009-11-07 | [
[
"Ghosh",
"Dilip Kumar",
""
],
[
"Kundu",
"Anirban",
""
],
[
"Roy",
"Probir",
""
],
[
"Roy",
"Sourov",
""
]
] | Though the minimal model of anomaly mediated supersymmetry breaking has been significantly constrained by recent experimental and theoretical work, there are still allowed regions of the parameter space for moderate to large values of $\tan\beta$. We show that these regions will be comprehensively probed in a ${\sqrt s} =1$ TeV $e^+e^-$ linear collider. Diagnostic signals to this end are studied by zeroing in on a unique and distinct feature of a large class of models in this genre: a neutral winolike Lightest Supersymmetric Particle closely degenerate in mass with a winolike chargino. The pair production processes $e^+e^- \to {\tilde e}_L^\pm {\tilde e}_L^\mp$, ${\tilde e}_R^\pm {\tilde e}_R^\mp$, ${\tilde e}_L^\pm {\tilde e}_R^\mp$, ${\tilde \nu} {\bar {\tilde \nu}}$, $\widetilde \chi^0_1 \widetilde \chi^0_2$, $\widetilde \chi^0_2 \widetilde \chi^0_2$ are all considered at $\sqrt s = 1$ TeV corresponding to the proposed TESLA linear collider in two natural categories of mass ordering in the sparticle spectra. The signals analysed comprise multiple combinations of fast charged leptons (any of which can act as the trigger) plus displaced vertices $X_D$ (any of which can be identified by a heavy ionizing track terminating in the detector) and/or associated soft pions with characteristic momentum distributions. |
2304.07052 | Zhi-Yong Zhou | Zhi-Yong Zhou, Chun-Yong Li, Zhiguang Xiao | A new look at $\psi(4160)$ and $\psi(4230)$ | 6 pages, 4 figures, 1 table | null | null | null | hep-ph hep-ex nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | By simultaneously analyzing the cross section data of $e^+e^-\rightarrow
D\bar D, D\bar D^*, D^*\bar D^*, D\bar D\pi$ in a coupled-channel scheme with
unitarity, we found that, in contrast to the conventional wisdom, the pole of
$\psi(2^3D_1)$ might be located at about $\sqrt{s}=4222-32i\mathrm{MeV}$. This
observation implies a possibility that the two resonances, dubbed the
$\psi(4160)$ and $\psi(4230)$ in the PDG table now, might be the same
$\psi(2^3D_1)$ state. Such a suggestion could provide more insight to our
understanding the enigmatic decay properties of $\psi(4160)$ and $\psi(4230)$.
Furthermore, this coupled-channel scheme could be applied to study other
phenomena with several interfering resonances.
| [
{
"created": "Fri, 14 Apr 2023 11:11:21 GMT",
"version": "v1"
}
] | 2023-04-17 | [
[
"Zhou",
"Zhi-Yong",
""
],
[
"Li",
"Chun-Yong",
""
],
[
"Xiao",
"Zhiguang",
""
]
] | By simultaneously analyzing the cross section data of $e^+e^-\rightarrow D\bar D, D\bar D^*, D^*\bar D^*, D\bar D\pi$ in a coupled-channel scheme with unitarity, we found that, in contrast to the conventional wisdom, the pole of $\psi(2^3D_1)$ might be located at about $\sqrt{s}=4222-32i\mathrm{MeV}$. This observation implies a possibility that the two resonances, dubbed the $\psi(4160)$ and $\psi(4230)$ in the PDG table now, might be the same $\psi(2^3D_1)$ state. Such a suggestion could provide more insight to our understanding the enigmatic decay properties of $\psi(4160)$ and $\psi(4230)$. Furthermore, this coupled-channel scheme could be applied to study other phenomena with several interfering resonances. |
2307.08495 | Nima Khosravi | Parisa Arabameri, Zahra Davari and Nima Khosravi | $k-$Dependent Dark Matter | 8 pages, 6 figures. comments are welcome | null | null | null | hep-ph astro-ph.CO | http://creativecommons.org/publicdomain/zero/1.0/ | With the emersion of precise cosmology and the emergence of cosmic tensions,
we are faced with the question of whether the simple model of cold dark matter
needs to be extended and whether doing so can alleviate the tensions and
improve our understanding of the properties of dark matter. In this study, we
investigate one of the generalized models of dark matter so that the behavior
of this dark matter changes according to the scale of $k$. In large scales
(small $k$'s), the dark matter is cold, while it becomes warm for small scales
(large $k$'s). This behavior is modeled phenomenologically for two different
scenarios. We show that the $S_8$ tension can be alleviated, but the $H_0$
tension becomes milder while not too much.
| [
{
"created": "Mon, 17 Jul 2023 13:57:20 GMT",
"version": "v1"
}
] | 2023-07-18 | [
[
"Arabameri",
"Parisa",
""
],
[
"Davari",
"Zahra",
""
],
[
"Khosravi",
"Nima",
""
]
] | With the emersion of precise cosmology and the emergence of cosmic tensions, we are faced with the question of whether the simple model of cold dark matter needs to be extended and whether doing so can alleviate the tensions and improve our understanding of the properties of dark matter. In this study, we investigate one of the generalized models of dark matter so that the behavior of this dark matter changes according to the scale of $k$. In large scales (small $k$'s), the dark matter is cold, while it becomes warm for small scales (large $k$'s). This behavior is modeled phenomenologically for two different scenarios. We show that the $S_8$ tension can be alleviated, but the $H_0$ tension becomes milder while not too much. |
2204.13605 | D\'ebora Barreiros | D.M. Barreiros, H.B. Camara, F.R. Joaquim | Flavour and dark matter in a scoto/type-II seesaw model | 51 LaTeX pages; 21 figures | null | 10.1007/JHEP08(2022)030 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The neutrino mass and dark matter (DM) problems are addressed in a Standard
Model extension where the type-II seesaw and scotogenic mechanisms coexist. The
model features a flavour $\mathcal{Z}_8$ discrete symmetry which is broken down
to a $\mathcal{Z}_2$, stabilising the (scalar or fermion) DM particle.
Spontaneous CP violation is implemented through the complex vacuum expectation
value of a singlet scalar field, inducing observable CP-violating effects in
the lepton sector. The structure of the effective neutrino mass matrix leads to
constraints on the low-energy neutrino observables, namely the atmospheric
neutrino mixing angle $\theta_{23}$, the Dirac CP-violating phase $\delta$ and
the absolute neutrino mass scale $m_{\rm lightest}$. In particular, in most
cases, the model selects one $\theta_{23}$ octant with $\delta \simeq 3\pi/2$.
Moreover, the obtained lower bounds on $m_{\rm lightest}$ are typically in the
range probed by cosmology. We also analyse the constraints imposed on the model
by current experimental limits on charged lepton flavour violating (cLFV)
processes, as well as future projected sensitivities. It is shown that the
Higgs triplet and scotogenic contributions to cLFV never overlap and that the
interplay among Yukawa couplings, dark charged scalar masses and mixing leads
to a wide parameter-space region compatible with current experimental bounds.
We investigate the scalar and fermion DM parameter space of our model by
considering relic density, direct-detection (DD) and collider constraints. For
scalar DM the mass interval $68 \ \text{GeV} \lesssim m_{\text{DM}} \lesssim 90
\ \text{GeV}$ is viable and will be probed by future DD searches. In the
fermion DM case, correct relic density is always obtained for $m_{\text{DM}}
\gtrsim 45$ GeV thanks to dark fermion-scalar coannihilation channels.
| [
{
"created": "Thu, 28 Apr 2022 16:06:09 GMT",
"version": "v1"
}
] | 2022-08-24 | [
[
"Barreiros",
"D. M.",
""
],
[
"Camara",
"H. B.",
""
],
[
"Joaquim",
"F. R.",
""
]
] | The neutrino mass and dark matter (DM) problems are addressed in a Standard Model extension where the type-II seesaw and scotogenic mechanisms coexist. The model features a flavour $\mathcal{Z}_8$ discrete symmetry which is broken down to a $\mathcal{Z}_2$, stabilising the (scalar or fermion) DM particle. Spontaneous CP violation is implemented through the complex vacuum expectation value of a singlet scalar field, inducing observable CP-violating effects in the lepton sector. The structure of the effective neutrino mass matrix leads to constraints on the low-energy neutrino observables, namely the atmospheric neutrino mixing angle $\theta_{23}$, the Dirac CP-violating phase $\delta$ and the absolute neutrino mass scale $m_{\rm lightest}$. In particular, in most cases, the model selects one $\theta_{23}$ octant with $\delta \simeq 3\pi/2$. Moreover, the obtained lower bounds on $m_{\rm lightest}$ are typically in the range probed by cosmology. We also analyse the constraints imposed on the model by current experimental limits on charged lepton flavour violating (cLFV) processes, as well as future projected sensitivities. It is shown that the Higgs triplet and scotogenic contributions to cLFV never overlap and that the interplay among Yukawa couplings, dark charged scalar masses and mixing leads to a wide parameter-space region compatible with current experimental bounds. We investigate the scalar and fermion DM parameter space of our model by considering relic density, direct-detection (DD) and collider constraints. For scalar DM the mass interval $68 \ \text{GeV} \lesssim m_{\text{DM}} \lesssim 90 \ \text{GeV}$ is viable and will be probed by future DD searches. In the fermion DM case, correct relic density is always obtained for $m_{\text{DM}} \gtrsim 45$ GeV thanks to dark fermion-scalar coannihilation channels. |
1411.2633 | Nikolaos Kidonakis | Nikolaos Kidonakis | NNNLO soft-gluon corrections for the top-quark $p_T$ and rapidity
distributions | 10 pages, 8 figures; additional curves in the figures; published
version | Phys. Rev. D 91, 031501 (2015) | 10.1103/PhysRevD.91.031501 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | I present a calculation of next-to-next-to-next-to-leading-order (NNNLO)
soft-gluon corrections for differential distributions in top-antitop pair
production in hadronic collisions. Approximate NNNLO (aNNNLO) results are
obtained from soft-gluon resummation. Theoretical predictions are shown for the
top-quark aNNNLO transverse momentum ($p_T$) and rapidity distributions at LHC
and Tevatron energies. The aNNNLO corrections enhance previous results for the
distributions but have smaller theoretical uncertainties.
| [
{
"created": "Mon, 10 Nov 2014 21:38:31 GMT",
"version": "v1"
},
{
"created": "Wed, 18 Feb 2015 23:08:35 GMT",
"version": "v2"
}
] | 2015-03-05 | [
[
"Kidonakis",
"Nikolaos",
""
]
] | I present a calculation of next-to-next-to-next-to-leading-order (NNNLO) soft-gluon corrections for differential distributions in top-antitop pair production in hadronic collisions. Approximate NNNLO (aNNNLO) results are obtained from soft-gluon resummation. Theoretical predictions are shown for the top-quark aNNNLO transverse momentum ($p_T$) and rapidity distributions at LHC and Tevatron energies. The aNNNLO corrections enhance previous results for the distributions but have smaller theoretical uncertainties. |
1512.08374 | Yuming Wang | Yu-Ming Wang | Non-dipolar gauge links for transverse-momentum-dependent pion wave
functions | 7 pages, 3 figures | null | 10.1051/epjconf/201611201021 | UWTHPH 2015-35 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | I discuss the factorization-compatible definitions of
transverse-momentum-dependent (TMD) pion wave functions which are fundamental
theory inputs entering QCD factorization formulae for many hard exclusive
processes. I will first demonstrate that the soft subtraction factor introduced
to remove both rapidity and pinch singularities can be greatly reduced by
making the maximal use of the freedom to construct the Wilson-line paths when
defining the TMD wave functions. I will then turn to show that the newly
proposed TMD definition with non-dipolar Wilson lines is equivalent to the one
with dipolar gauge links and with a complicated soft function, to all orders of
the perturbative expansion in the strong coupling, as far as the infrared
behavior is concerned.
| [
{
"created": "Mon, 28 Dec 2015 10:59:54 GMT",
"version": "v1"
}
] | 2016-04-20 | [
[
"Wang",
"Yu-Ming",
""
]
] | I discuss the factorization-compatible definitions of transverse-momentum-dependent (TMD) pion wave functions which are fundamental theory inputs entering QCD factorization formulae for many hard exclusive processes. I will first demonstrate that the soft subtraction factor introduced to remove both rapidity and pinch singularities can be greatly reduced by making the maximal use of the freedom to construct the Wilson-line paths when defining the TMD wave functions. I will then turn to show that the newly proposed TMD definition with non-dipolar Wilson lines is equivalent to the one with dipolar gauge links and with a complicated soft function, to all orders of the perturbative expansion in the strong coupling, as far as the infrared behavior is concerned. |
hep-ph/0009208 | Finn Ravndal | Finn Ravndal | Problems with the Casimir Vacuum Energy | 10 pages, Latex with 1 figure. Extended version of contributed talk
at 'Vacuum Energy and the Cosmological Constant', NORDITA, Copenhagen, August
24 - 26, 2000 | null | null | null | hep-ph quant-ph | null | A critical look is taken at the calculation of the Casimir effect. The
boundary conditions play an important role and should be imposed in a physical
way. An acceptable result for the vacuum energy is only obtained when different
regularization schemes yield the same result. Radiative corrections to the
Casimir force between two parallel plates due to electromagnetic vacuum
fluctuations have been obtained both in full QED and in a low-energy, effective
field theory with conflicting results. Including surface terms in the effective
Lagrangian, the QED result can be understood. Finally, a problem with the
electromagnetic vacuum energy on $S^3$ is pointed out and a solution suggested.
The structure of higher order corrections to this result is discussed.
| [
{
"created": "Mon, 18 Sep 2000 11:35:11 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Ravndal",
"Finn",
""
]
] | A critical look is taken at the calculation of the Casimir effect. The boundary conditions play an important role and should be imposed in a physical way. An acceptable result for the vacuum energy is only obtained when different regularization schemes yield the same result. Radiative corrections to the Casimir force between two parallel plates due to electromagnetic vacuum fluctuations have been obtained both in full QED and in a low-energy, effective field theory with conflicting results. Including surface terms in the effective Lagrangian, the QED result can be understood. Finally, a problem with the electromagnetic vacuum energy on $S^3$ is pointed out and a solution suggested. The structure of higher order corrections to this result is discussed. |
hep-ph/0505145 | Rafael Montemayor | Belinka Gonzalez, Santiago A. Martinez, R. Montemayor and Luis F.
Urrutia | Lorentz violating electrodynamics | 11 pages, extended version of the talk given by L.F. Urrutia in the
VI Mexican School: Approaches to Quantum Gravity, Playa del Carmen, Mexico,
Nov. 2004. Minor chages in the text and added references | J.Phys.Conf.Ser. 24 (2005) 58-68 | 10.1088/1742-6596/24/1/008 | null | hep-ph | null | After summarizing the most interesting results in the calculation of
synchrotron radiation in the Myers-Pospelov effective model for Lorentz
invariance violating (LIV) electrodynamics, we present a general unified way of
describing the radiation regime of LIV electrodynamics which include the
following three different models : Gambini-Pullin, Ellis et al. and
Myers-Pospelov. Such unification reduces to the standard approach of radiation
in a dispersive and absortive (in general) medium with a given index of
refraction. The formulation is presented up to second order in the LIV
parameter and it is explicitly applied to the synchrotron radiation case.
| [
{
"created": "Tue, 17 May 2005 03:45:20 GMT",
"version": "v1"
},
{
"created": "Sat, 21 May 2005 14:50:37 GMT",
"version": "v2"
}
] | 2009-11-11 | [
[
"Gonzalez",
"Belinka",
""
],
[
"Martinez",
"Santiago A.",
""
],
[
"Montemayor",
"R.",
""
],
[
"Urrutia",
"Luis F.",
""
]
] | After summarizing the most interesting results in the calculation of synchrotron radiation in the Myers-Pospelov effective model for Lorentz invariance violating (LIV) electrodynamics, we present a general unified way of describing the radiation regime of LIV electrodynamics which include the following three different models : Gambini-Pullin, Ellis et al. and Myers-Pospelov. Such unification reduces to the standard approach of radiation in a dispersive and absortive (in general) medium with a given index of refraction. The formulation is presented up to second order in the LIV parameter and it is explicitly applied to the synchrotron radiation case. |
2007.09648 | Simon Platzer | Matthew De Angelis, Jeffrey R. Forshaw, Simon Pl\"atzer | Resummation and simulation of soft gluon effects beyond leading colour | 7 pages, 7 figures; update to plots after bugfix, minor changes to
formulations; no qualitative change | Phys. Rev. Lett. 126, 112001 (2021) | 10.1103/PhysRevLett.126.112001 | MAN/HEP/2020/008, MCnet-20-11, UWTHPH-2019-10 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present first results of resumming soft gluon effects in a simulation of
high energy collisions beyond the leading-colour approximation. We work to all
orders in QCD perturbation theory using a new parton branching algorithm. This
amplitude evolution algorithm resembles a parton shower that is able to
systematically include colour-suppressed terms. We find that colour suppressed
terms can significantly contribute to jet veto cross sections.
| [
{
"created": "Sun, 19 Jul 2020 10:44:42 GMT",
"version": "v1"
},
{
"created": "Wed, 29 Jul 2020 17:46:32 GMT",
"version": "v2"
}
] | 2021-03-24 | [
[
"De Angelis",
"Matthew",
""
],
[
"Forshaw",
"Jeffrey R.",
""
],
[
"Plätzer",
"Simon",
""
]
] | We present first results of resumming soft gluon effects in a simulation of high energy collisions beyond the leading-colour approximation. We work to all orders in QCD perturbation theory using a new parton branching algorithm. This amplitude evolution algorithm resembles a parton shower that is able to systematically include colour-suppressed terms. We find that colour suppressed terms can significantly contribute to jet veto cross sections. |
1606.07063 | Zhong-Bo Kang | Zhong-Bo Kang, Felix Ringer, Ivan Vitev | Jet substructure using semi-inclusive jet functions within SCET | 28 pages, 6 figures, published version | JHEP 11 (2016) 155 | 10.1007/JHEP11(2016)155 | null | hep-ph hep-ex nucl-ex nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We propose a new method to evaluate jet substructure observables in inclusive
jet measurements, based upon semi-inclusive jet functions in the framework of
Soft Collinear Effective Theory (SCET). As a first example, we consider the jet
fragmentation function, where a hadron $h$ is identified inside a fully
reconstructed jet. We introduce a new semi-inclusive fragmenting jet function
${\mathcal G}^h_i(z= \omega_J/\omega,z_h=\omega_h/\omega_J,\omega_J, R,\mu)$,
which depends on the jet radius $R$ and the large light-cone momenta of the
parton `$i$' initiating the jet ($\omega$), the jet ($\omega_J$), and the
hadron $h$ ($\omega_h$). The jet fragmentation function can then be expressed
as a semi-inclusive observable, in the spirit of actual experimental
measurements, rather than as an exclusive one. We demonstrate the consistency
of the effective field theory treatment and standard perturbative QCD
calculations of this observable at next-to-leading order (NLO). The
renormalization group (RG) equation for the semi-inclusive fragmenting jet
function ${\mathcal G}_i^h(z,z_h, \omega_J, R,\mu)$ are also derived and shown
to follow exactly the usual timelike DGLAP evolution equations for
fragmentation functions. The newly obtained RG equations can be used to perform
the resummation of single logarithms of the jet radius parameter $R$ up to
next-to-leading logarithmic (NLL$_R$) accuracy. In combination with the fixed
NLO calculation, we obtain NLO+NLL$_R$ results for the hadron distribution
inside the jet. We present numerical results for $pp\to(\mathrm{jet}\,h)X$ in
the new framework, and find excellent agreement with existing LHC experimental
data.
| [
{
"created": "Wed, 22 Jun 2016 20:00:00 GMT",
"version": "v1"
},
{
"created": "Sun, 27 Nov 2016 21:00:07 GMT",
"version": "v2"
}
] | 2016-11-29 | [
[
"Kang",
"Zhong-Bo",
""
],
[
"Ringer",
"Felix",
""
],
[
"Vitev",
"Ivan",
""
]
] | We propose a new method to evaluate jet substructure observables in inclusive jet measurements, based upon semi-inclusive jet functions in the framework of Soft Collinear Effective Theory (SCET). As a first example, we consider the jet fragmentation function, where a hadron $h$ is identified inside a fully reconstructed jet. We introduce a new semi-inclusive fragmenting jet function ${\mathcal G}^h_i(z= \omega_J/\omega,z_h=\omega_h/\omega_J,\omega_J, R,\mu)$, which depends on the jet radius $R$ and the large light-cone momenta of the parton `$i$' initiating the jet ($\omega$), the jet ($\omega_J$), and the hadron $h$ ($\omega_h$). The jet fragmentation function can then be expressed as a semi-inclusive observable, in the spirit of actual experimental measurements, rather than as an exclusive one. We demonstrate the consistency of the effective field theory treatment and standard perturbative QCD calculations of this observable at next-to-leading order (NLO). The renormalization group (RG) equation for the semi-inclusive fragmenting jet function ${\mathcal G}_i^h(z,z_h, \omega_J, R,\mu)$ are also derived and shown to follow exactly the usual timelike DGLAP evolution equations for fragmentation functions. The newly obtained RG equations can be used to perform the resummation of single logarithms of the jet radius parameter $R$ up to next-to-leading logarithmic (NLL$_R$) accuracy. In combination with the fixed NLO calculation, we obtain NLO+NLL$_R$ results for the hadron distribution inside the jet. We present numerical results for $pp\to(\mathrm{jet}\,h)X$ in the new framework, and find excellent agreement with existing LHC experimental data. |
1807.10713 | Max Zoller | Federico Buccioni, Jean-Nicolas Lang, Stefano Pozzorini, Hantian Zhang
and Max Zoller | On-the-fly reduction of open loops | Contribution to the Proceedings of Loops and Legs in Quantum Field
Theory (LL2018), 29 April 2018 - 04 May 2018, St. Goar, Germany | PoS(LL2018)045 | null | ZH-TH 29/18 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We describe new developments in the OpenLoops framework based on the recently
introduced on-the-fly method. The on-the-fly approach exploits the
factorisation of one-loop diagrams into segments in order to perform various
operations, such as helicity summation, diagram merging and the reduction of
Feynman integrands in between the recursion steps for the amplitude
construction. This method significantly reduces the complexity of scattering
amplitude calculations for multi-particle processes, leading to a major
increase in CPU efficiency and numerical stability. The unification of the
reduction to scalar integrals with the amplitude construction in a single
algorithm, allows to identify problematic kinematical configurations and cure
numerical instabilities in single recursion steps. A simple permutation trick
in combination with a one-parameter expansion for a single topology, which is
now implemented to any order, eliminate rank-two Gram determinant instabilities
altogether. Due to this any-order expansion, the numerical accuracy of the
algorithm can be determined with a rescaling test. The on-the-fly algorithm is
fully implemented for double and quadruple precision, which allows for true
quadruple precision benchmarks with up to 32 correct digits as well as a
powerful rescue system for unstable points. We present first speed and
stability results for these new features. The on-the-fly algorithm is part of
the forthcoming release of OpenLoops 2.
| [
{
"created": "Fri, 27 Jul 2018 16:31:44 GMT",
"version": "v1"
}
] | 2018-07-30 | [
[
"Buccioni",
"Federico",
""
],
[
"Lang",
"Jean-Nicolas",
""
],
[
"Pozzorini",
"Stefano",
""
],
[
"Zhang",
"Hantian",
""
],
[
"Zoller",
"Max",
""
]
] | We describe new developments in the OpenLoops framework based on the recently introduced on-the-fly method. The on-the-fly approach exploits the factorisation of one-loop diagrams into segments in order to perform various operations, such as helicity summation, diagram merging and the reduction of Feynman integrands in between the recursion steps for the amplitude construction. This method significantly reduces the complexity of scattering amplitude calculations for multi-particle processes, leading to a major increase in CPU efficiency and numerical stability. The unification of the reduction to scalar integrals with the amplitude construction in a single algorithm, allows to identify problematic kinematical configurations and cure numerical instabilities in single recursion steps. A simple permutation trick in combination with a one-parameter expansion for a single topology, which is now implemented to any order, eliminate rank-two Gram determinant instabilities altogether. Due to this any-order expansion, the numerical accuracy of the algorithm can be determined with a rescaling test. The on-the-fly algorithm is fully implemented for double and quadruple precision, which allows for true quadruple precision benchmarks with up to 32 correct digits as well as a powerful rescue system for unstable points. We present first speed and stability results for these new features. The on-the-fly algorithm is part of the forthcoming release of OpenLoops 2. |
0912.2354 | Won Sang Cho | Won Sang Cho, Jihn E. Kim, Ji-Hun Kim | Amplification of endpoint structure for new particle mass measurement at
the LHC | LaTeX file of 14 pages with 6 figures, small clarifications and more
cuts on simulation, version to appear in Phys. Rev. D. | Phys.Rev.D81:095010,2010 | 10.1103/PhysRevD.81.095010 | null | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We introduce a new collider variable, MCT2, named as constransverse mass. It
is a mixture of `stransverse mass(MT2)' and `contransverse mass(MCT)'
variables, where the usual endpoint structure of MT2 distribution can be
amplified in the MCT2 basis by large Jacobian factor which is controlled by
trial missing particle mass. Thus the MCT2 projection of events increases our
observability to measure several important endpoints from new particle decays,
which are usually expected to be buried by irreducible backgrounds with various
systematic uncertainties at the LHC. In this paper we explain the phenomenology
of endpoint amplification in MCT2 projection, and describe how one may employ
this variable to measure several meaningful mass constraints of new particles.
| [
{
"created": "Mon, 14 Dec 2009 20:52:29 GMT",
"version": "v1"
},
{
"created": "Thu, 22 Apr 2010 08:04:47 GMT",
"version": "v2"
},
{
"created": "Fri, 23 Apr 2010 06:11:58 GMT",
"version": "v3"
}
] | 2015-03-13 | [
[
"Cho",
"Won Sang",
""
],
[
"Kim",
"Jihn E.",
""
],
[
"Kim",
"Ji-Hun",
""
]
] | We introduce a new collider variable, MCT2, named as constransverse mass. It is a mixture of `stransverse mass(MT2)' and `contransverse mass(MCT)' variables, where the usual endpoint structure of MT2 distribution can be amplified in the MCT2 basis by large Jacobian factor which is controlled by trial missing particle mass. Thus the MCT2 projection of events increases our observability to measure several important endpoints from new particle decays, which are usually expected to be buried by irreducible backgrounds with various systematic uncertainties at the LHC. In this paper we explain the phenomenology of endpoint amplification in MCT2 projection, and describe how one may employ this variable to measure several meaningful mass constraints of new particles. |
hep-ph/0507031 | Luis Bento | Zurab Berezhiani and Luis Bento | Neutron - Mirror Neutron Oscillations: How Fast Might They Be? | 4 pages, 1 figure; revtex; matches paper published by P.R.L | Phys.Rev.Lett. 96 (2006) 081801 | 10.1103/PhysRevLett.96.081801 | null | hep-ph | null | We discuss the phenomenological implications of the neutron (n) oscillation
into the mirror neutron (n'), a hypothetical particle exactly degenerate in
mass with the neutron but sterile to normal matter. We show that the present
experimental data allow a maximal n-n' oscillation in vacuum with a
characteristic time $\tau$ much shorter than the neutron lifetime, in fact as
small as 1 sec. This phenomenon may manifest in neutron disappearance and
regeneration experiments perfectly accessible to present experimental
capabilities and may also have interesting astrophysical consequences, in
particular for the propagation of ultra high energy cosmic rays.
| [
{
"created": "Sun, 3 Jul 2005 18:22:42 GMT",
"version": "v1"
},
{
"created": "Tue, 5 Jul 2005 19:03:45 GMT",
"version": "v2"
},
{
"created": "Mon, 20 Feb 2006 00:50:08 GMT",
"version": "v3"
}
] | 2015-06-25 | [
[
"Berezhiani",
"Zurab",
""
],
[
"Bento",
"Luis",
""
]
] | We discuss the phenomenological implications of the neutron (n) oscillation into the mirror neutron (n'), a hypothetical particle exactly degenerate in mass with the neutron but sterile to normal matter. We show that the present experimental data allow a maximal n-n' oscillation in vacuum with a characteristic time $\tau$ much shorter than the neutron lifetime, in fact as small as 1 sec. This phenomenon may manifest in neutron disappearance and regeneration experiments perfectly accessible to present experimental capabilities and may also have interesting astrophysical consequences, in particular for the propagation of ultra high energy cosmic rays. |
0809.4904 | Andrei V. Frolov | Andrei V. Frolov | DEFROST: A New Code for Simulating Preheating after Inflation | RevTeX 4.0; 16 pages, 9 figures | JCAP 0811:009,2008 | 10.1088/1475-7516/2008/11/009 | SCG-2008-02 | hep-ph astro-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | At the end of inflation, dynamical instability can rapidly deposit the energy
of homogeneous cold inflaton into excitations of other fields. This process,
known as preheating, is rather violent, inhomogeneous and non-linear, and has
to be studied numerically. This paper presents a new code for simulating scalar
field dynamics in expanding universe written for that purpose. Compared to
available alternatives, it significantly improves both the speed and the
accuracy of calculations, and is fully instrumented for 3D visualization. We
reproduce previously published results on preheating in simple chaotic
inflation models, and further investigate non-linear dynamics of the inflaton
decay. Surprisingly, we find that the fields do not want to thermalize quite
the way one would think. Instead of directly reaching equilibrium, the
evolution appears to be stuck in a rather simple but quite inhomogeneous state.
In particular, one-point distribution function of total energy density appears
to be universal among various two-field preheating models, and is exceedingly
well described by a lognormal distribution. It is tempting to attribute this
state to scalar field turbulence.
| [
{
"created": "Mon, 29 Sep 2008 08:28:11 GMT",
"version": "v1"
},
{
"created": "Wed, 29 Oct 2008 03:28:09 GMT",
"version": "v2"
}
] | 2009-03-27 | [
[
"Frolov",
"Andrei V.",
""
]
] | At the end of inflation, dynamical instability can rapidly deposit the energy of homogeneous cold inflaton into excitations of other fields. This process, known as preheating, is rather violent, inhomogeneous and non-linear, and has to be studied numerically. This paper presents a new code for simulating scalar field dynamics in expanding universe written for that purpose. Compared to available alternatives, it significantly improves both the speed and the accuracy of calculations, and is fully instrumented for 3D visualization. We reproduce previously published results on preheating in simple chaotic inflation models, and further investigate non-linear dynamics of the inflaton decay. Surprisingly, we find that the fields do not want to thermalize quite the way one would think. Instead of directly reaching equilibrium, the evolution appears to be stuck in a rather simple but quite inhomogeneous state. In particular, one-point distribution function of total energy density appears to be universal among various two-field preheating models, and is exceedingly well described by a lognormal distribution. It is tempting to attribute this state to scalar field turbulence. |
1510.06851 | Shabbar Raza | Tianjun Li, Shabbar Raza and Xiao-Chuan Wang | The Super-Natural Supersymmetry and Its Classic Example: M-Theory
Inspired NMSSM | 35 pages, 12 figures and two tables | Phys. Rev. D 93, 115014 (2016) | 10.1103/PhysRevD.93.115014 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We briefly review the super-natural supersymmetry (SUSY), which provides a
most promising solution to the SUSY electroweak fine-tuning problem. In
particular, we address its subtle issues as well. Unlike the Minimal
Supersymmetric Standard model (MSSM), the Next to MSSM (NMSSM) can be scale
invariant and has no mass parameter in its Lagrangian before SUSY and gauge
symmetry breakings. Therefore, the NMSSM is a perfect framework for
super-natural SUSY. To give the SUSY breaking soft mass to the singlet, we
consider the moduli and dilaton dominant SUSY breaking scenarios in M-theory on
$S^1/Z_2$. In these scenarios, SUSY is broken by one and only one $F$-term of
moduli or dilaton, and the SUSY breaking soft terms can be determined via the
K\"ahler potential and superpotential from Calabi-Yau compactification of
M-theory on $S^1/Z_2$. Thus, as predicted by super-natural SUSY, the SUSY
electroweak fine-tuning measure is of unity order. In the moduli dominant SUSY
breaking scenario, the right-handed sleptons are relatively light around 1 TeV,
stau can be even as light as 580 GeV and degenerate with the lightest
neutralino, chargino masses are larger than 1 TeV, the light stop masses are
around 2 TeV or larger, the first two-generation squark masses are about 3 TeV
or larger, and gluinos are heavier than squarks. In the dilaton dominant SUSY
breaking scenario, the qualitative picture remain the same but we have heavier
spectra as compared to moduli dominant SUSY breaking scenario. In addition to
it, we have Higgs $H_{2}/A_{1}$-resonance solutions for dark matter (DM). In
both scenarios, the minimal value of DM relic density is about 0.2. To obtain
the observed DM relic density, we can consider the dilution effect from
supercritical string cosmology or introduce the axino as the lightest
supersymmetric particle.
| [
{
"created": "Fri, 23 Oct 2015 08:01:08 GMT",
"version": "v1"
}
] | 2016-06-15 | [
[
"Li",
"Tianjun",
""
],
[
"Raza",
"Shabbar",
""
],
[
"Wang",
"Xiao-Chuan",
""
]
] | We briefly review the super-natural supersymmetry (SUSY), which provides a most promising solution to the SUSY electroweak fine-tuning problem. In particular, we address its subtle issues as well. Unlike the Minimal Supersymmetric Standard model (MSSM), the Next to MSSM (NMSSM) can be scale invariant and has no mass parameter in its Lagrangian before SUSY and gauge symmetry breakings. Therefore, the NMSSM is a perfect framework for super-natural SUSY. To give the SUSY breaking soft mass to the singlet, we consider the moduli and dilaton dominant SUSY breaking scenarios in M-theory on $S^1/Z_2$. In these scenarios, SUSY is broken by one and only one $F$-term of moduli or dilaton, and the SUSY breaking soft terms can be determined via the K\"ahler potential and superpotential from Calabi-Yau compactification of M-theory on $S^1/Z_2$. Thus, as predicted by super-natural SUSY, the SUSY electroweak fine-tuning measure is of unity order. In the moduli dominant SUSY breaking scenario, the right-handed sleptons are relatively light around 1 TeV, stau can be even as light as 580 GeV and degenerate with the lightest neutralino, chargino masses are larger than 1 TeV, the light stop masses are around 2 TeV or larger, the first two-generation squark masses are about 3 TeV or larger, and gluinos are heavier than squarks. In the dilaton dominant SUSY breaking scenario, the qualitative picture remain the same but we have heavier spectra as compared to moduli dominant SUSY breaking scenario. In addition to it, we have Higgs $H_{2}/A_{1}$-resonance solutions for dark matter (DM). In both scenarios, the minimal value of DM relic density is about 0.2. To obtain the observed DM relic density, we can consider the dilution effect from supercritical string cosmology or introduce the axino as the lightest supersymmetric particle. |
1312.5614 | Jaime Hern\'andez-S\'anchez Dr. | A. Cordero-Cid, J. Hernandez-Sanchez, C.G. Honorato, S. Moretti, M.A.
Perez and A. Rosado | Impact of a four-zero Yukawa texture on $h\to \gamma \gamma$ and $\gamma
Z$ in the framework of the Two Higgs Doublet Model Type III | 26 pages, 13 figures. Version accepted for publication in JHEP | null | 10.1007/JHEP07(2014)057 | DCP-13-05 | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study the substantial enhancement, with respect to the corresponding
Standard Model rates, that can be obtained for the branching ratios of the
decay channels $h \to \gamma \gamma$ and $h\to \gamma Z$ within the framework
of the Two Higgs Doublet Model Type III, assuming a four-zero Yukawa texture
and a general Higgs potential. We show that these processes are very sensitive
to the flavor pattern entering the Yukawa texture and to the triple coupling
structure of the Higgs potential, both of which impact onto the aforementioned
decays. We can accommodate the parameters of the model in such a way to obtain
the $h \to \gamma \gamma$ rates reported by the Large Hadron Collider and at
the same time we get a $h\to \gamma Z$ fraction much larger than in the
Standard Model, indeed within experimental reach. We present some scenarios
where this phenomenology is realized for spectrum configurations that are
consistent with current constraints. We also discuss the possibility of
obtaining a light charged Higgs boson compatible with all such measurements,
thereby serving the purpose of providing a hallmark signal of the scenario
considered.
| [
{
"created": "Thu, 19 Dec 2013 16:19:14 GMT",
"version": "v1"
},
{
"created": "Fri, 13 Jun 2014 02:52:44 GMT",
"version": "v2"
}
] | 2015-06-18 | [
[
"Cordero-Cid",
"A.",
""
],
[
"Hernandez-Sanchez",
"J.",
""
],
[
"Honorato",
"C. G.",
""
],
[
"Moretti",
"S.",
""
],
[
"Perez",
"M. A.",
""
],
[
"Rosado",
"A.",
""
]
] | We study the substantial enhancement, with respect to the corresponding Standard Model rates, that can be obtained for the branching ratios of the decay channels $h \to \gamma \gamma$ and $h\to \gamma Z$ within the framework of the Two Higgs Doublet Model Type III, assuming a four-zero Yukawa texture and a general Higgs potential. We show that these processes are very sensitive to the flavor pattern entering the Yukawa texture and to the triple coupling structure of the Higgs potential, both of which impact onto the aforementioned decays. We can accommodate the parameters of the model in such a way to obtain the $h \to \gamma \gamma$ rates reported by the Large Hadron Collider and at the same time we get a $h\to \gamma Z$ fraction much larger than in the Standard Model, indeed within experimental reach. We present some scenarios where this phenomenology is realized for spectrum configurations that are consistent with current constraints. We also discuss the possibility of obtaining a light charged Higgs boson compatible with all such measurements, thereby serving the purpose of providing a hallmark signal of the scenario considered. |
hep-ph/0001148 | Thomas A. Trainor | T. A. Trainor | Event-by-Event Analysis and the Central Limit Theorem | 40 pages, 10 figures | null | null | null | hep-ph | null | Event-by-event analysis of heavy-ion collision events is an important tool
for the study of the QCD phase boundary and formation of a quark-gluon plasma.
A universal feature of phase boundaries is the appearance of increased
fluctuations of conserved measures as manifested by excess measure variance
compared to a reference. In this paper I consider a particular aspect of EbyE
analysis emphasizing global-variables variance comparisons and the central
limit theorem. I find that the central limit theorem is, in a broader
interpretation, a statement about the scale invariance of total variance for a
measure distribution, which in turn relates to the scale-dependent symmetry
properties of the distribution.. I further generalize this concept to the
relationship between the scale dependence of a covariance matrix for all
conserved measures defined on a dynamical system and a matrix of covariance
integrals defined on two-point measure spaces, which points the way to a
detailed description of the symmetry dynamics of a complex measure system.
Finally, I relate this generalized description to several recently proposed or
completed event-by-event analyses.
| [
{
"created": "Mon, 17 Jan 2000 01:39:11 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Trainor",
"T. A.",
""
]
] | Event-by-event analysis of heavy-ion collision events is an important tool for the study of the QCD phase boundary and formation of a quark-gluon plasma. A universal feature of phase boundaries is the appearance of increased fluctuations of conserved measures as manifested by excess measure variance compared to a reference. In this paper I consider a particular aspect of EbyE analysis emphasizing global-variables variance comparisons and the central limit theorem. I find that the central limit theorem is, in a broader interpretation, a statement about the scale invariance of total variance for a measure distribution, which in turn relates to the scale-dependent symmetry properties of the distribution.. I further generalize this concept to the relationship between the scale dependence of a covariance matrix for all conserved measures defined on a dynamical system and a matrix of covariance integrals defined on two-point measure spaces, which points the way to a detailed description of the symmetry dynamics of a complex measure system. Finally, I relate this generalized description to several recently proposed or completed event-by-event analyses. |
2004.00087 | Arie Bodek | Arie Bodek and Tejin Cai | Comparison of optical potential for nucleons and $\Delta$ resonances | 15 pages, 11 figures, 2 tables. Version 5 as published in Eur. Phys.
Journal C 2020 | Eur. Phys. J. C 80, 655 (2020) | 10.1140/epjc/s10052-020-8236-8 | null | hep-ph nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Precise modeling of neutrino interactions on nuclear targets is essential for
neutrino oscillations experiments. The modeling of the energy of final state
particles in quasielastic (QE) scattering and resonance production on bound
nucleons requires knowledge of both the removal energy of the initial state
bound nucleon as well as the average Coulomb and nuclear optical potentials for
final state leptons and hadrons. We extract the average values of the real part
of the nuclear optical potential for final state nucleons ($U_{opt}^{QE}$) as a
function of the nucleon kinetic energy from inclusive electron scattering data
on nuclear targets ($\bf_{6}^{12}C$+$\bf_{8}^{16}O$,
$\bf_{20}^{40}Ca$+$\bf_{18}^{40}Ar$, $\bf_{3}^{6}Li$, $\bf_{18}^{27}Al$,
$\bf_{26}^{56}Fe$, $\bf_{82}^{208}Pb$) in the QE region and compare to
calculations. We also extract values of the average of the real part of the
nuclear optical potential for a $\Delta(1232)$ resonance in the final state
($U^\Delta_{opt}$) within the impulse approximation. We find that
$U^\Delta_{opt}$ is more negative than $U_{opt}^{QE}$ with
$U^\Delta_{opt}\approx$1.5~$U_{opt}^{QE}$ for $\bf_{6}^{12}C$.
| [
{
"created": "Tue, 31 Mar 2020 20:18:19 GMT",
"version": "v1"
},
{
"created": "Mon, 6 Apr 2020 16:16:38 GMT",
"version": "v2"
},
{
"created": "Sun, 12 Apr 2020 20:53:57 GMT",
"version": "v3"
},
{
"created": "Sat, 4 Jul 2020 11:25:55 GMT",
"version": "v4"
}
] | 2020-08-07 | [
[
"Bodek",
"Arie",
""
],
[
"Cai",
"Tejin",
""
]
] | Precise modeling of neutrino interactions on nuclear targets is essential for neutrino oscillations experiments. The modeling of the energy of final state particles in quasielastic (QE) scattering and resonance production on bound nucleons requires knowledge of both the removal energy of the initial state bound nucleon as well as the average Coulomb and nuclear optical potentials for final state leptons and hadrons. We extract the average values of the real part of the nuclear optical potential for final state nucleons ($U_{opt}^{QE}$) as a function of the nucleon kinetic energy from inclusive electron scattering data on nuclear targets ($\bf_{6}^{12}C$+$\bf_{8}^{16}O$, $\bf_{20}^{40}Ca$+$\bf_{18}^{40}Ar$, $\bf_{3}^{6}Li$, $\bf_{18}^{27}Al$, $\bf_{26}^{56}Fe$, $\bf_{82}^{208}Pb$) in the QE region and compare to calculations. We also extract values of the average of the real part of the nuclear optical potential for a $\Delta(1232)$ resonance in the final state ($U^\Delta_{opt}$) within the impulse approximation. We find that $U^\Delta_{opt}$ is more negative than $U_{opt}^{QE}$ with $U^\Delta_{opt}\approx$1.5~$U_{opt}^{QE}$ for $\bf_{6}^{12}C$. |
1101.3923 | J. T. Londergan | T.J. Hobbs, J.T. Londergan, D.P. Murdock and A.W. Thomas | Testing Partonic Charge Symmetry at a High-Energy Electron Collider | 7 pages, 4 figures | Phys.Lett.B698:123-127,2011 | 10.1016/j.physletb.2011.02.040 | null | hep-ph nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We examine the possibility that one could measure partonic charge symmetry
violation (CSV) by comparing neutrino or antineutrino production through
charged-current reactions induced by electrons or positrons at a possible
electron collider at the LHC. We calculate the magnitude of CSV that might be
expected at such a facility. We show that this is likely to be a several
percent effect, substantially larger than the typical CSV effects expected for
partonic reactions.
| [
{
"created": "Thu, 20 Jan 2011 15:00:34 GMT",
"version": "v1"
}
] | 2015-03-17 | [
[
"Hobbs",
"T. J.",
""
],
[
"Londergan",
"J. T.",
""
],
[
"Murdock",
"D. P.",
""
],
[
"Thomas",
"A. W.",
""
]
] | We examine the possibility that one could measure partonic charge symmetry violation (CSV) by comparing neutrino or antineutrino production through charged-current reactions induced by electrons or positrons at a possible electron collider at the LHC. We calculate the magnitude of CSV that might be expected at such a facility. We show that this is likely to be a several percent effect, substantially larger than the typical CSV effects expected for partonic reactions. |
2309.05284 | Sarthak Satapathy | Sarthak Satapathy, Rajeev Singh, Pushpa Panday, Salman Ahamad Khan and
Debarshi Dey | Shear viscosity of rotating, hot, and dense spin-half fermionic systems
from quantum field theory | 14 pages, 4 figures. arXiv admin note: substantial text overlap with
arXiv:2307.09953 | null | null | null | hep-ph hep-th nucl-th | http://creativecommons.org/licenses/by/4.0/ | In this study, we calculate the shear viscosity for rotating fermions with
spin-half under conditions of high temperature and density. We employ the Kubo
formalism, rooted in finite-temperature quantum field theory, to compute the
field correlation functions essential for this evaluation. The one-loop diagram
pertinent to shear viscosity is analyzed within the context of curved space,
utilizing tetrad formalism as an effective approach in cylindrical coordinates.
Our findings focus on extremely high angular velocities, ranging from 0.1 to 1
GeV, which align with experimental expectations. Furthermore, we explore the
inter-relationship between the chemical potential and angular velocity within
the scope of this study.
| [
{
"created": "Mon, 11 Sep 2023 07:57:04 GMT",
"version": "v1"
},
{
"created": "Tue, 23 Jan 2024 05:57:07 GMT",
"version": "v2"
},
{
"created": "Sun, 21 Apr 2024 15:11:39 GMT",
"version": "v3"
}
] | 2024-04-23 | [
[
"Satapathy",
"Sarthak",
""
],
[
"Singh",
"Rajeev",
""
],
[
"Panday",
"Pushpa",
""
],
[
"Khan",
"Salman Ahamad",
""
],
[
"Dey",
"Debarshi",
""
]
] | In this study, we calculate the shear viscosity for rotating fermions with spin-half under conditions of high temperature and density. We employ the Kubo formalism, rooted in finite-temperature quantum field theory, to compute the field correlation functions essential for this evaluation. The one-loop diagram pertinent to shear viscosity is analyzed within the context of curved space, utilizing tetrad formalism as an effective approach in cylindrical coordinates. Our findings focus on extremely high angular velocities, ranging from 0.1 to 1 GeV, which align with experimental expectations. Furthermore, we explore the inter-relationship between the chemical potential and angular velocity within the scope of this study. |
1204.6622 | Haiying Cai | Haiying Cai | D-term Enhancement in Spin-1 Top Partner Model | 11 pages, 4 figures and references added, updated EW bound for the
mass of vector top partner | Phys. Rev. D 85, 115020 (2012) | 10.1103/PhysRevD.85.115020 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Supersymmetric models with extended electroweak gauge groups have the
potential to enhance the Higgs quartic interaction through nondecoupling
D-terms. We consider the D-term enhancement effect in a vector top partner
model, where the quadratic divergence to the Higgs mass from the virtual top
quark is canceled by its corresponding spin-1 superpartners. We are going to
show that the model can predict a Higgs mass beyond the LEP bound, and is
consistent with the precision electroweak constraints.
| [
{
"created": "Mon, 30 Apr 2012 13:19:34 GMT",
"version": "v1"
},
{
"created": "Mon, 28 May 2012 06:08:50 GMT",
"version": "v2"
},
{
"created": "Sun, 12 Aug 2012 10:28:34 GMT",
"version": "v3"
},
{
"created": "Mon, 9 Jun 2014 06:21:18 GMT",
"version": "v4"
}
] | 2014-06-10 | [
[
"Cai",
"Haiying",
""
]
] | Supersymmetric models with extended electroweak gauge groups have the potential to enhance the Higgs quartic interaction through nondecoupling D-terms. We consider the D-term enhancement effect in a vector top partner model, where the quadratic divergence to the Higgs mass from the virtual top quark is canceled by its corresponding spin-1 superpartners. We are going to show that the model can predict a Higgs mass beyond the LEP bound, and is consistent with the precision electroweak constraints. |
hep-ph/0401025 | Ernest Ma | Ernest Ma (UC Riverside) | Lepton Family Symmetry and Neutrino Mass Matrix | 9 pages, including 1 figure | Mod.Phys.Lett. A19 (2004) 577-582 | 10.1142/S0217732304013374 | UCRHEP-T368 (Jan 04) | hep-ph | null | The standard model of leptons is extended to accommodate a discrete Z_3 X Z_2
family symmetry. After rotating the charged-lepton mass matrix to its diagonal
form, the neutrino mass matrix reveals itself as very suitable for explaining
atmospheric and solar neutrino oscillation data. A generic requirement of this
approach is the appearance of three Higgs doublets at the electroweak scale,
with observable flavor violating decays.
| [
{
"created": "Tue, 6 Jan 2004 21:04:38 GMT",
"version": "v1"
}
] | 2009-11-10 | [
[
"Ma",
"Ernest",
"",
"UC Riverside"
]
] | The standard model of leptons is extended to accommodate a discrete Z_3 X Z_2 family symmetry. After rotating the charged-lepton mass matrix to its diagonal form, the neutrino mass matrix reveals itself as very suitable for explaining atmospheric and solar neutrino oscillation data. A generic requirement of this approach is the appearance of three Higgs doublets at the electroweak scale, with observable flavor violating decays. |
hep-ph/0605289 | Rabindra N. Mohapatra | R. N. Mohapatra | Observable Neutron-Anti-Neutron Oscillation, Baryogenesis and High Scale
Seesaw | 10 pages; 3 figures; Invited Plenary talk at the WHEPP9 symposium in
Bhubaneswar, India; January, 2006 | Pramana67:783-792,2006 | 10.1007/s12043-006-0091-0 | null | hep-ph | null | Seesaw mechanism has been a dominant paradigm in the discussion of neutrino
masses. I discuss how this idea can be tested via a baryon number violating
process such as $N-\bar{N}$ oscillation. Since the expected seesaw scale is
high and the $N-\bar{N}$ amplitude goes like $M^{-5}_{R}$, one might think that
this process is not observable in realistic seesaw models for neutrino masses.
In this talk I show that in supersymmetric models, the above conclusion is
circumvented leading to an enhanced and observable rate for $N-\bar{N}$
oscillation. I also discuss a new mechanism for baryogenesis in generic models
for neutron-anti-neutron oscillation and show how the requirement of adequate
baryogenesis can put an upper limit on the neutron-anti-neutron oscillation
time.
| [
{
"created": "Fri, 26 May 2006 17:08:08 GMT",
"version": "v1"
}
] | 2008-11-26 | [
[
"Mohapatra",
"R. N.",
""
]
] | Seesaw mechanism has been a dominant paradigm in the discussion of neutrino masses. I discuss how this idea can be tested via a baryon number violating process such as $N-\bar{N}$ oscillation. Since the expected seesaw scale is high and the $N-\bar{N}$ amplitude goes like $M^{-5}_{R}$, one might think that this process is not observable in realistic seesaw models for neutrino masses. In this talk I show that in supersymmetric models, the above conclusion is circumvented leading to an enhanced and observable rate for $N-\bar{N}$ oscillation. I also discuss a new mechanism for baryogenesis in generic models for neutron-anti-neutron oscillation and show how the requirement of adequate baryogenesis can put an upper limit on the neutron-anti-neutron oscillation time. |
hep-ph/0103001 | Andrea Ferroglia | A. Ferroglia, G. Ossola, and A. Sirlin | Scale-Independent Calculation of $\sin^2 \theta_{eff}^{lept}$ | 12 pages, 2 figures | Phys.Lett. B507 (2001) 147-152 | 10.1016/S0370-2693(01)00438-5 | NYU-TH/01/02/02 | hep-ph | null | We present a calculation of the electroweak mixing parameter $\sin^2
\theta_{eff}^{lept}$ that incorporates known higher order effects, shares the
desirable convergence properties of the $\bar{MS}$ scheme, and has the
important theoretical advantage of being strictly independent of the
electroweak scale in finite orders of perturbation theory . We also show how
this formulation can be extended to the calculation of the W mass $M_W$. The
results provide accurate, scale-independent evaluations of these important
parameters, as functions of the Higgs boson mass $M_H$, and are compared with
previous calculations in order to analyze the scheme and scale dependence of
the electroweak corrections.
| [
{
"created": "Thu, 1 Mar 2001 16:50:14 GMT",
"version": "v1"
}
] | 2009-11-07 | [
[
"Ferroglia",
"A.",
""
],
[
"Ossola",
"G.",
""
],
[
"Sirlin",
"A.",
""
]
] | We present a calculation of the electroweak mixing parameter $\sin^2 \theta_{eff}^{lept}$ that incorporates known higher order effects, shares the desirable convergence properties of the $\bar{MS}$ scheme, and has the important theoretical advantage of being strictly independent of the electroweak scale in finite orders of perturbation theory . We also show how this formulation can be extended to the calculation of the W mass $M_W$. The results provide accurate, scale-independent evaluations of these important parameters, as functions of the Higgs boson mass $M_H$, and are compared with previous calculations in order to analyze the scheme and scale dependence of the electroweak corrections. |
hep-ph/9402206 | Wojciech Broniowski | W. Broniowski | Low-energy sum rules and large-$N_c$ consistency conditions | 25 p. (REVTEX, Feynman.tex for figures) | Nucl.Phys. A580 (1994) 429-444 | 10.1016/0375-9474(94)90907-5 | U. Regensburg TPR-93-39 | hep-ph | null | The large-$N_c$ consistency conditions for axial vector and isovector
magnetic couplings of pions to baryons are discussed from the point of view of
low-energy current-algebra sum rules (Adler-Weisberger, Cabibbo-Radicati). In
particular, we show how the result that ratios of axial vector and isovector
magnetic coupling constants get corrections only at the order $1/N_c^2$ follows
from the $N_c$-counting of appropriate cross sections. This counting is
performed using various approaches at the quark and hadronic level. Other
implications of our method are also presented.
| [
{
"created": "Wed, 2 Feb 1994 12:53:47 GMT",
"version": "v1"
}
] | 2009-10-28 | [
[
"Broniowski",
"W.",
""
]
] | The large-$N_c$ consistency conditions for axial vector and isovector magnetic couplings of pions to baryons are discussed from the point of view of low-energy current-algebra sum rules (Adler-Weisberger, Cabibbo-Radicati). In particular, we show how the result that ratios of axial vector and isovector magnetic coupling constants get corrections only at the order $1/N_c^2$ follows from the $N_c$-counting of appropriate cross sections. This counting is performed using various approaches at the quark and hadronic level. Other implications of our method are also presented. |
0811.0246 | Mert Aybat | S. Mert Aybat and George Sterman | Soft-Gluon Cancellation, Phases and Factorization with Initial-State
Partons | 6 pages, 1 figure | Phys.Lett.B671:46-50,2009 | 10.1016/j.physletb.2008.11.050 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We outline arguments for the cancellation of soft singularities in transition
probabilities and parton distributions with incoming partons and Wilson lines,
and with observed jets or heavy colored particles in the final states. We show
the cancellation of Glauber gluons and divergent phases, relating finite
remainders to corrections that arise from restrictions on final states in
factorized cross sections.
| [
{
"created": "Mon, 3 Nov 2008 15:39:06 GMT",
"version": "v1"
}
] | 2009-02-02 | [
[
"Aybat",
"S. Mert",
""
],
[
"Sterman",
"George",
""
]
] | We outline arguments for the cancellation of soft singularities in transition probabilities and parton distributions with incoming partons and Wilson lines, and with observed jets or heavy colored particles in the final states. We show the cancellation of Glauber gluons and divergent phases, relating finite remainders to corrections that arise from restrictions on final states in factorized cross sections. |
1001.4236 | Alfredo Valcarce | A. Valcarce, J. Vijande, T. Fernandez-Carames | Charmonium molecules? | 5 pages, 2 figures. To appear in the Proceedings of XIII
International Conference on Hadron Spectroscopy, November 29 - December 4,
2009, Florida State University | null | 10.1063/1.3483347 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this talk we present some recent studies of multiquark components in the
charmonium sector. We study the possible existence of compact four quark-states
and meson-meson molecules in the charmonium spectroscopy.
| [
{
"created": "Mon, 25 Jan 2010 18:25:29 GMT",
"version": "v1"
}
] | 2015-05-18 | [
[
"Valcarce",
"A.",
""
],
[
"Vijande",
"J.",
""
],
[
"Fernandez-Carames",
"T.",
""
]
] | In this talk we present some recent studies of multiquark components in the charmonium sector. We study the possible existence of compact four quark-states and meson-meson molecules in the charmonium spectroscopy. |
hep-ph/9209250 | Greg Anderson | Greg W. Anderson, Stuart Raby, Savas Dimopoulos, and Lawrence Hall | Precise predictions for mt, Vcb and tan | (beta), 13 pages pages of text plus figures and captions.
OHSTPY-HEP-92-018, LBL-332817, UCB-PTH-92/28, Stanford-92-25 | Phys.Rev.D47:3702-3706,1993 | 10.1103/PhysRevD.47.R3702 | null | hep-ph | null | The fermion mass and mixing angle predictions of a recently proposed
framework are investigated for large b and $\tau$ Yukawa couplings. A new
allowed region of parameters is found for this large $\tan \beta$ case. The two
predictions which are substantially altered, $m_t$ and $\tan \beta$, are
displayed, including the dependence on the inputs $|V_{cb}|$, $m_c$, $m_b$ and
$\alpha_s$. A simple restriction on this framework yields an additional
prediction, for $|V_{cb}|$. If the b,t, and $\tau$ Yukawas are equal at the GUT
scale then $|\Vcb|$ is predicted and the top quark mass is constrained to lie
in the range $\mt = 179. \pm 4.$ GeV.
| [
{
"created": "Fri, 18 Sep 1992 02:25:00 GMT",
"version": "v1"
}
] | 2010-11-01 | [
[
"Anderson",
"Greg W.",
""
],
[
"Raby",
"Stuart",
""
],
[
"Dimopoulos",
"Savas",
""
],
[
"Hall",
"Lawrence",
""
]
] | The fermion mass and mixing angle predictions of a recently proposed framework are investigated for large b and $\tau$ Yukawa couplings. A new allowed region of parameters is found for this large $\tan \beta$ case. The two predictions which are substantially altered, $m_t$ and $\tan \beta$, are displayed, including the dependence on the inputs $|V_{cb}|$, $m_c$, $m_b$ and $\alpha_s$. A simple restriction on this framework yields an additional prediction, for $|V_{cb}|$. If the b,t, and $\tau$ Yukawas are equal at the GUT scale then $|\Vcb|$ is predicted and the top quark mass is constrained to lie in the range $\mt = 179. \pm 4.$ GeV. |
2311.01134 | Martin Gabelmann | Henning Bahl, Johannes Braathen, Martin Gabelmann, Georg Weiglein | Precise predictions for the trilinear Higgs self-coupling in the
Standard Model and beyond | 6 pages, The European Physical Society Conference on High Energy
Physics (EPS-HEP2023) | null | null | DESY-23-166 | hep-ph | http://creativecommons.org/licenses/by-nc-nd/4.0/ | Deviations in the trilinear self-coupling of the Higgs boson at 125 GeV from
the Standard Model (SM) prediction are a sensitive test of physics Beyond the
SM (BSM). The LHC experiments searching for the simultaneous production of two
Higgs bosons start to become sensitive to such deviations. Therefore, precise
predictions for the trilinear Higgs self-coupling in different BSM models are
required in order to be able to test them against current and future bounds. We
present the new framework $\texttt{anyH3}$, which is a $\texttt{Python}$
library that can be utilized to obtain predictions for trilinear scalar
couplings up to the one-loop level in any renormalisable theory. The program
makes use of the $\texttt{UFO}$ format as input and is able to automatically
apply a wide variety of renormalisation schemes involving minimal and
non-minimal subtraction conditions. External-leg corrections are also computed
automatically, and finite external momenta can be optionally taken into
account. The $\texttt{Python}$ library comes with convenient command-line as
well as $\texttt{Mathematica}$ user interfaces. We perform cross-checks using
consistency conditions such as UV-finiteness and decoupling, and also by
comparing against results know in the literature. As example applications, we
obtain results for the trilinear self-coupling of the SM-like Higgs boson in
various concrete BSM models, study the effect of external momenta as well as of
different renormalisation schemes.
| [
{
"created": "Thu, 2 Nov 2023 10:30:05 GMT",
"version": "v1"
}
] | 2023-11-03 | [
[
"Bahl",
"Henning",
""
],
[
"Braathen",
"Johannes",
""
],
[
"Gabelmann",
"Martin",
""
],
[
"Weiglein",
"Georg",
""
]
] | Deviations in the trilinear self-coupling of the Higgs boson at 125 GeV from the Standard Model (SM) prediction are a sensitive test of physics Beyond the SM (BSM). The LHC experiments searching for the simultaneous production of two Higgs bosons start to become sensitive to such deviations. Therefore, precise predictions for the trilinear Higgs self-coupling in different BSM models are required in order to be able to test them against current and future bounds. We present the new framework $\texttt{anyH3}$, which is a $\texttt{Python}$ library that can be utilized to obtain predictions for trilinear scalar couplings up to the one-loop level in any renormalisable theory. The program makes use of the $\texttt{UFO}$ format as input and is able to automatically apply a wide variety of renormalisation schemes involving minimal and non-minimal subtraction conditions. External-leg corrections are also computed automatically, and finite external momenta can be optionally taken into account. The $\texttt{Python}$ library comes with convenient command-line as well as $\texttt{Mathematica}$ user interfaces. We perform cross-checks using consistency conditions such as UV-finiteness and decoupling, and also by comparing against results know in the literature. As example applications, we obtain results for the trilinear self-coupling of the SM-like Higgs boson in various concrete BSM models, study the effect of external momenta as well as of different renormalisation schemes. |
0708.0867 | Yue-Liang Wu | Yue-Liang Wu | Gauge Theory Model of the Neutrino and New Physics Beyond the Standard
Model | 15 pages, only typos in table 1 corrected in this replaced version | Phys.Rev.D77:113009,2008 | 10.1103/PhysRevD.77.113009 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Majorana features of neutrinos and SO(3) gauge symmetry of three families
enable us to construct a gauge model of neutrino for understanding naturally
the observed smallness of neutrino masses and the nearly tri-bimaximal neutrino
mixing when combining together with the mechanism of approximate global U(1)
family symmetry. The vacuum structure of SO(3) symmetry breaking is found to
play an important role. The mixing angle $\theta_{13}$ and CP-violating phases
governed by the vacuum of spontaneous symmetry breaking are in general non-zero
and testable experimentally at the allowed sensitivity. The model predicts the
existence of vector-like SO(3) triplet charged leptons and vector-like SO(3)
triplet Majorana neutrinos as well as SO(3) tri-triplet Higgs bosons, some of
them can be light and explored at the colliders LHC and ILC.
| [
{
"created": "Tue, 7 Aug 2007 14:17:02 GMT",
"version": "v1"
},
{
"created": "Mon, 5 May 2008 09:17:37 GMT",
"version": "v2"
},
{
"created": "Sun, 29 Jun 2008 08:17:43 GMT",
"version": "v3"
},
{
"created": "Mon, 5 Mar 2012 09:43:31 GMT",
"version": "v4"
}
] | 2012-03-06 | [
[
"Wu",
"Yue-Liang",
""
]
] | Majorana features of neutrinos and SO(3) gauge symmetry of three families enable us to construct a gauge model of neutrino for understanding naturally the observed smallness of neutrino masses and the nearly tri-bimaximal neutrino mixing when combining together with the mechanism of approximate global U(1) family symmetry. The vacuum structure of SO(3) symmetry breaking is found to play an important role. The mixing angle $\theta_{13}$ and CP-violating phases governed by the vacuum of spontaneous symmetry breaking are in general non-zero and testable experimentally at the allowed sensitivity. The model predicts the existence of vector-like SO(3) triplet charged leptons and vector-like SO(3) triplet Majorana neutrinos as well as SO(3) tri-triplet Higgs bosons, some of them can be light and explored at the colliders LHC and ILC. |
2004.07095 | Tamas Cs\"org\H{o} | T. Csorgo, T. Novak, R. Pasechnik, A. Ster and I. Szanyi | Proton Holography -- Discovering Odderon from Scaling Properties of
Elastic Scattering | 10 pages in one-column (better readable) form, 2 figures, invited
theory talk of T. Csorgo at the ISMD 2019 conference in Santa Fe, NM, USA,
final version, to appear in EPJ Web of Conferences (in two-column format) | EPJ Web Conf. 235 (2020) 06002 | 10.1051/epjconf/202023506002 | null | hep-ph hep-ex nucl-ex nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We investigate the scaling properties of elastic scattering data at ISR and
LHC energies and find that the significance of an Odderon observation is larger
than the discovery threshold of 5$\sigma$. As an unexpected by-product of these
investigations, for certain experimentally relevant cases, we also conjecture
the possibility of proton holography with the help of elastic proton-proton
scattering.
| [
{
"created": "Wed, 15 Apr 2020 14:01:48 GMT",
"version": "v1"
},
{
"created": "Mon, 11 May 2020 18:48:39 GMT",
"version": "v2"
}
] | 2021-02-01 | [
[
"Csorgo",
"T.",
""
],
[
"Novak",
"T.",
""
],
[
"Pasechnik",
"R.",
""
],
[
"Ster",
"A.",
""
],
[
"Szanyi",
"I.",
""
]
] | We investigate the scaling properties of elastic scattering data at ISR and LHC energies and find that the significance of an Odderon observation is larger than the discovery threshold of 5$\sigma$. As an unexpected by-product of these investigations, for certain experimentally relevant cases, we also conjecture the possibility of proton holography with the help of elastic proton-proton scattering. |
hep-ph/0308107 | Y. B. Bergner | Y. Bergner, Luis M. A. Bettencourt | The self-consistent bounce: an improved nucleation rate | 28 pages, revtex, 7 eps figures | Phys.Rev. D69 (2004) 045012 | 10.1103/PhysRevD.69.045012 | MIT-CTP-3404 | hep-ph | null | We generalize the standard computation of homogeneous nucleation theory at
zero temperature to a scenario in which the bubble shape is determined
self-consistently with its quantum fluctuations. Studying two scalar models in
1+1 dimensions, we find the self-consistent bounce by employing a two-particle
irreducible (2PI) effective action in imaginary time at the level of the
Hartree approximation. We thus obtain an effective single bounce action which
determines the rate exponent. We use collective coordinates to account for the
translational invariance and the growth instability of the bubble and finally
present a new nucleation rate prefactor. We compare the results with those
obtained using the standard 1-loop approximation and show that the
self-consistent rate can differ by several orders of magnitude.
| [
{
"created": "Sun, 10 Aug 2003 14:45:28 GMT",
"version": "v1"
},
{
"created": "Thu, 23 Oct 2003 00:38:55 GMT",
"version": "v2"
}
] | 2009-11-10 | [
[
"Bergner",
"Y.",
""
],
[
"Bettencourt",
"Luis M. A.",
""
]
] | We generalize the standard computation of homogeneous nucleation theory at zero temperature to a scenario in which the bubble shape is determined self-consistently with its quantum fluctuations. Studying two scalar models in 1+1 dimensions, we find the self-consistent bounce by employing a two-particle irreducible (2PI) effective action in imaginary time at the level of the Hartree approximation. We thus obtain an effective single bounce action which determines the rate exponent. We use collective coordinates to account for the translational invariance and the growth instability of the bubble and finally present a new nucleation rate prefactor. We compare the results with those obtained using the standard 1-loop approximation and show that the self-consistent rate can differ by several orders of magnitude. |
hep-ph/0301158 | Jakovac Antal | A. Jakovac | Quantum corrections to Boltzmann equations | 5 pages, Latex, 1 eps figure. To appear in the proceedings of Strong
and Electroweak Matter (SEWM 2002), Heidelberg, Germany, 2-5 Oct 2002 | null | 10.1142/9789812704498_0054 | null | hep-ph | null | Because of IR (pinch) singularities a resummation is necessary in
non-equilibrium field theories, that can be performed by using Kadanoff--Baym
equations. Taking Landau prescription correctly into account, Kadanoff--Baym
equations reduce to Boltzmann equations only in a restricted kinematical range;
in other cases a new equation (the former constraint equation) has to be
considered. In relaxation time approximation this new equation results in the
shifting and smearing of multiparticle thresholds.
| [
{
"created": "Mon, 20 Jan 2003 10:56:23 GMT",
"version": "v1"
}
] | 2017-08-23 | [
[
"Jakovac",
"A.",
""
]
] | Because of IR (pinch) singularities a resummation is necessary in non-equilibrium field theories, that can be performed by using Kadanoff--Baym equations. Taking Landau prescription correctly into account, Kadanoff--Baym equations reduce to Boltzmann equations only in a restricted kinematical range; in other cases a new equation (the former constraint equation) has to be considered. In relaxation time approximation this new equation results in the shifting and smearing of multiparticle thresholds. |
hep-ph/0005106 | Antonio D. Polosa | V. Elias, A.D. Polosa, M.D. Scadron and N.A. T\"ornqvist | Footprints of a Broad $\sigma$(600) in Weak-Interaction Processes | 14 pages, minor typos corrected, improved presentation | Mod.Phys.Lett. A17 (2002) 569-581 | 10.1142/S021773230200676X | HIP-2000-22/TH | hep-ph | null | We explore how chiral-symmetry constraints on weak-interaction matrix
elements suggest the existence of an intermediate state sigma in several
different weak-interaction processes. Particular attention is directed toward
recent evidence for a sigma within three-body nonleptonic weak decays.
| [
{
"created": "Thu, 11 May 2000 09:18:12 GMT",
"version": "v1"
},
{
"created": "Thu, 10 Aug 2000 09:48:25 GMT",
"version": "v2"
},
{
"created": "Wed, 22 May 2002 09:13:01 GMT",
"version": "v3"
}
] | 2009-10-31 | [
[
"Elias",
"V.",
""
],
[
"Polosa",
"A. D.",
""
],
[
"Scadron",
"M. D.",
""
],
[
"Törnqvist",
"N. A.",
""
]
] | We explore how chiral-symmetry constraints on weak-interaction matrix elements suggest the existence of an intermediate state sigma in several different weak-interaction processes. Particular attention is directed toward recent evidence for a sigma within three-body nonleptonic weak decays. |
hep-ph/0210349 | J. Smit | Jonivar Skullerud, Jan Smit and Anders Tranberg | W-Particle Distribution in ElectroWeak Tachyonic Pre-Heating | Contribution to Strong and ElectroWeak Matter 2002, 5 pages | null | 10.1142/9789812704498_0070 | null | hep-ph hep-lat | null | Results are presented of a numerical study of the distribution of W-bosons
generated in a tachyonic electroweak pre-heating transition
| [
{
"created": "Fri, 25 Oct 2002 10:08:08 GMT",
"version": "v1"
}
] | 2017-08-23 | [
[
"Skullerud",
"Jonivar",
""
],
[
"Smit",
"Jan",
""
],
[
"Tranberg",
"Anders",
""
]
] | Results are presented of a numerical study of the distribution of W-bosons generated in a tachyonic electroweak pre-heating transition |
hep-ph/0002161 | null | Christian W. Bauer, Zoltan Ligeti and Michael Luke | A Model Independent Determination of |V_{ub}| | 11 pages; some references added, version to appear in PLB | Phys.Lett.B479:395-401,2000 | 10.1016/S0370-2693(00)00318-X | UTPT-00-02, FERMILAB-Pub-00/039-T | hep-ph | null | It is shown that measuring the lepton invariant mass spectrum in inclusive
semileptonic B -> X_u l nu decay yields a model independent determination of
|V_{ub}|. Unlike the lepton energy and hadronic invariant mass spectra,
nonperturbative effects are only important in the resonance region, and play a
parametrically suppressed role when d\Gamma/dq^2 is integrated over q^2 >
(m_B-m_D)^2, which is required to eliminate the charm background. Perturbative
and nonperturbative corrections are presented to order \alpha_s^2\beta_0 and
\Lambda_{QCD}^2/m_b^2, and the \Lambda_{QCD}^3/m_b^3 corrections are used to
estimate the uncertainty in our results. The utility of the B -> X_s l^+ l^-
decay rate above the \psi(2S) resonance is discussed.
| [
{
"created": "Tue, 15 Feb 2000 06:36:47 GMT",
"version": "v1"
},
{
"created": "Tue, 4 Apr 2000 19:58:17 GMT",
"version": "v2"
}
] | 2010-11-23 | [
[
"Bauer",
"Christian W.",
""
],
[
"Ligeti",
"Zoltan",
""
],
[
"Luke",
"Michael",
""
]
] | It is shown that measuring the lepton invariant mass spectrum in inclusive semileptonic B -> X_u l nu decay yields a model independent determination of |V_{ub}|. Unlike the lepton energy and hadronic invariant mass spectra, nonperturbative effects are only important in the resonance region, and play a parametrically suppressed role when d\Gamma/dq^2 is integrated over q^2 > (m_B-m_D)^2, which is required to eliminate the charm background. Perturbative and nonperturbative corrections are presented to order \alpha_s^2\beta_0 and \Lambda_{QCD}^2/m_b^2, and the \Lambda_{QCD}^3/m_b^3 corrections are used to estimate the uncertainty in our results. The utility of the B -> X_s l^+ l^- decay rate above the \psi(2S) resonance is discussed. |
2105.05771 | Joao G. Rosa | Jo\~ao G. Rosa and Lu\'is B. Ventura | Spontaneous breaking of the Peccei-Quinn symmetry during warm inflation | 12 pages, 6 figures | null | null | null | hep-ph astro-ph.CO gr-qc | http://creativecommons.org/licenses/by-nc-nd/4.0/ | We show that, for values of the axion decay constant parametrically close to
the GUT scale, the Peccei-Quinn phase transition may naturally occur during
warm inflation. This results from interactions between the Peccei-Quinn scalar
field and the ambient thermal bath, which is sustained by the inflaton field
through dissipative effects. It is therefore possible for the axion field to
appear as a dynamical degree of freedom only after observable CMB scales have
become super-horizon, thus avoiding the large-scale axion isocurvature
perturbations that typically plague such models. This nevertheless yields a
nearly scale-invariant spectrum of axion isocurvature perturbations on small
scales, with a density contrast of up to a few percent, which may have a
significant impact on the formation of gravitationally-bound axion structures
such as mini-clusters.
| [
{
"created": "Wed, 12 May 2021 16:39:41 GMT",
"version": "v1"
}
] | 2021-05-13 | [
[
"Rosa",
"João G.",
""
],
[
"Ventura",
"Luís B.",
""
]
] | We show that, for values of the axion decay constant parametrically close to the GUT scale, the Peccei-Quinn phase transition may naturally occur during warm inflation. This results from interactions between the Peccei-Quinn scalar field and the ambient thermal bath, which is sustained by the inflaton field through dissipative effects. It is therefore possible for the axion field to appear as a dynamical degree of freedom only after observable CMB scales have become super-horizon, thus avoiding the large-scale axion isocurvature perturbations that typically plague such models. This nevertheless yields a nearly scale-invariant spectrum of axion isocurvature perturbations on small scales, with a density contrast of up to a few percent, which may have a significant impact on the formation of gravitationally-bound axion structures such as mini-clusters. |
1903.10369 | Hua-Xing Chen | Er-Liang Cui, Hui-Min Yang, Hua-Xing Chen and Atsushi Hosaka | Identifying the $\Xi_{b}(6227)$ and $\Sigma_{b}(6097)$ as $P$-wave
bottom baryons of $J^P = 3/2^-$ | 18 pages, 5 figures, 4 tables, published in PRD. arXiv admin note:
text overlap with arXiv:1703.07703 | Phys. Rev. D 99, 094021 (2019) | 10.1103/PhysRevD.99.094021 | null | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We use the method of QCD sum rules within the framework of heavy quark
effective theory to study the mass spectrum of the $\Sigma_{b}(6097)^{\pm}$ and
$\Xi_{b}(6227)^{-}$, and use the method of light-cone sum rules still within
the heavy quark effective theory to study their decay properties. Our results
suggest that they can be well interpreted as $P$-wave bottom baryons with the
spin-parity $J^P = 3/2^-$. They belong to the baryon doublet $[\mathbf{6}_F, 2,
1, \lambda]$, where the total and spin angular momenta of the light degree of
freedom are $j_l = 2$ and $s_l = 1$, and the orbital angular momentum is
between the bottom quark and the two-light-quark system ($\lambda$-type). This
doublet contains six bottom baryons, and we predict masses (mass differences)
and decay widths of the other four states to be $M_{\Omega_b(3/2^-)} = 6.46 \pm
0.12 {~\rm GeV}$, $\Gamma_{\Omega_b(3/2^-)} = 58{^{+65}_{-33}} {~\rm MeV}$,
$M_{\Sigma_b(5/2^-)}-M_{\Sigma_b(3/2^-)}= 13 \pm 5 {~\rm MeV}$,
$M_{\Xi_b^{\prime}(5/2^-)}-M_{\Xi_b^{\prime}(3/2^-)} = 12 \pm 5 {~\rm MeV}$,
and $M_{\Omega_b(5/2^-)}-M_{\Omega_b(3/2^-)} = 11 \pm 5 {~\rm MeV}$. We propose
to search for them in further LHCb experiments.
| [
{
"created": "Mon, 25 Mar 2019 14:38:25 GMT",
"version": "v1"
},
{
"created": "Sat, 8 Jun 2019 00:48:34 GMT",
"version": "v2"
}
] | 2019-06-11 | [
[
"Cui",
"Er-Liang",
""
],
[
"Yang",
"Hui-Min",
""
],
[
"Chen",
"Hua-Xing",
""
],
[
"Hosaka",
"Atsushi",
""
]
] | We use the method of QCD sum rules within the framework of heavy quark effective theory to study the mass spectrum of the $\Sigma_{b}(6097)^{\pm}$ and $\Xi_{b}(6227)^{-}$, and use the method of light-cone sum rules still within the heavy quark effective theory to study their decay properties. Our results suggest that they can be well interpreted as $P$-wave bottom baryons with the spin-parity $J^P = 3/2^-$. They belong to the baryon doublet $[\mathbf{6}_F, 2, 1, \lambda]$, where the total and spin angular momenta of the light degree of freedom are $j_l = 2$ and $s_l = 1$, and the orbital angular momentum is between the bottom quark and the two-light-quark system ($\lambda$-type). This doublet contains six bottom baryons, and we predict masses (mass differences) and decay widths of the other four states to be $M_{\Omega_b(3/2^-)} = 6.46 \pm 0.12 {~\rm GeV}$, $\Gamma_{\Omega_b(3/2^-)} = 58{^{+65}_{-33}} {~\rm MeV}$, $M_{\Sigma_b(5/2^-)}-M_{\Sigma_b(3/2^-)}= 13 \pm 5 {~\rm MeV}$, $M_{\Xi_b^{\prime}(5/2^-)}-M_{\Xi_b^{\prime}(3/2^-)} = 12 \pm 5 {~\rm MeV}$, and $M_{\Omega_b(5/2^-)}-M_{\Omega_b(3/2^-)} = 11 \pm 5 {~\rm MeV}$. We propose to search for them in further LHCb experiments. |
hep-ph/0208007 | Kimmo Tuominen | J.T. Lenaghan and K. Tuominen | Saturation and Pion Production in Proton-Nucleus Collisions | 4 pages, 3 eps-figures | null | null | NORDITA-2002-35 HE | hep-ph | null | We study the effects of gluon saturation on pion production in high energy
proton-nucleus collisions using the color glass condensate model. At high
p_perp, we show that the p_perp-distribution of gluons behaves as ~
1/(p_perp^7) in accordance with both conventional perturbative QCD calculations
and experiment. Fragmentation of gluons into pions leads to a rapidity
dependent depletion of pions relative to the conventional perturbative QCD
predictions. We argue that these clear and systematic differences provide a
signal for the onset of gluon saturation which is accessible in upcoming
experiments.
| [
{
"created": "Thu, 1 Aug 2002 11:14:11 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Lenaghan",
"J. T.",
""
],
[
"Tuominen",
"K.",
""
]
] | We study the effects of gluon saturation on pion production in high energy proton-nucleus collisions using the color glass condensate model. At high p_perp, we show that the p_perp-distribution of gluons behaves as ~ 1/(p_perp^7) in accordance with both conventional perturbative QCD calculations and experiment. Fragmentation of gluons into pions leads to a rapidity dependent depletion of pions relative to the conventional perturbative QCD predictions. We argue that these clear and systematic differences provide a signal for the onset of gluon saturation which is accessible in upcoming experiments. |
hep-ph/0310271 | Lorenzo Magnea | Tim Oliver Eynck, Eric Laenen and Lorenzo Magnea | Exponentiation at partonic threshold for the Drell-Yan cross section | Talk presented by L. Magnea at the 11th International Workshop on
Deep Inelastic Scattering (DIS 2003), St. Petersburg, Russia, 23-27 Apr 2003 | null | null | null | hep-ph | null | The techniques leading to the resummation of threshold logarithms in the
Drell-Yan cross section and other processes can be used to show that also terms
independent on the Mellin variable N exponentiate. Comparison with explicit
two-loop calculations shows that within this class of terms the exponentiation
of the one-loop result together with the running of the coupling is the
dominant effect at two loops.
| [
{
"created": "Thu, 23 Oct 2003 07:52:46 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Eynck",
"Tim Oliver",
""
],
[
"Laenen",
"Eric",
""
],
[
"Magnea",
"Lorenzo",
""
]
] | The techniques leading to the resummation of threshold logarithms in the Drell-Yan cross section and other processes can be used to show that also terms independent on the Mellin variable N exponentiate. Comparison with explicit two-loop calculations shows that within this class of terms the exponentiation of the one-loop result together with the running of the coupling is the dominant effect at two loops. |
1512.07443 | Barbara Betz | Barbara Betz, Florian Senzel, Carsten Greiner, and Miklos Gyulassy | The impact of the medium and the jet-medium coupling on jet measurements
at RHIC and LHC | 5 pages, 4 figures | null | null | null | hep-ph hep-ex nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We compare a perturbative QCD-based jet-energy loss model to the measured
data of the pion nuclear modification factor and the high-pT elliptic flow at
RHIC and LHC energies. This jet-energy loss model (BBMG) is currently coupled
to state-of-the-art hydrodynamic descriptions. We report on a model extension
to medium backgrounds generated by the parton cascade BAMPS. In addition, we
study the impact of realistic medium transverse flow fields and a jet-medium
coupling which includes the effects of the jet energy, the temperature of the
bulk medium, and non-equilibrium effects close to the phase transition. By
contrasting the two different background models, we point out that the
description of the high-pT elliptic flow for a non-fluctuating medium requires
to include such a jet-medium coupling and the transverse flow fields. While the
results for both medium backgrounds show a remarkable similarity, there is an
impact of the background medium and the background flow on the high-pT elliptic
flow.
| [
{
"created": "Wed, 23 Dec 2015 12:01:42 GMT",
"version": "v1"
}
] | 2015-12-24 | [
[
"Betz",
"Barbara",
""
],
[
"Senzel",
"Florian",
""
],
[
"Greiner",
"Carsten",
""
],
[
"Gyulassy",
"Miklos",
""
]
] | We compare a perturbative QCD-based jet-energy loss model to the measured data of the pion nuclear modification factor and the high-pT elliptic flow at RHIC and LHC energies. This jet-energy loss model (BBMG) is currently coupled to state-of-the-art hydrodynamic descriptions. We report on a model extension to medium backgrounds generated by the parton cascade BAMPS. In addition, we study the impact of realistic medium transverse flow fields and a jet-medium coupling which includes the effects of the jet energy, the temperature of the bulk medium, and non-equilibrium effects close to the phase transition. By contrasting the two different background models, we point out that the description of the high-pT elliptic flow for a non-fluctuating medium requires to include such a jet-medium coupling and the transverse flow fields. While the results for both medium backgrounds show a remarkable similarity, there is an impact of the background medium and the background flow on the high-pT elliptic flow. |
1508.05043 | Narayan Rana | Taushif Ahmed, Goutam Das, Prakash Mathews, Narayan Rana and V.
Ravindran | Spin-2 Form Factors at Three Loop in QCD | 20 pages, 2 figures | null | 10.1007/JHEP12(2015)084 | null | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Spin-2 fields are often candidates in physics beyond the Standard Model
namely the models with extra-dimensions where spin-2 Kaluza-Klein gravitons
couple to the fields of the SM. Also, in the context of Higgs searches, spin-2
fields have been studied as an alternative to the scalar Higgs boson. In this
article, we present the complete three loop QCD radiative corrections to the
spin-2 quark-antiquark and spin-2 gluon-gluon form factors in SU(N) gauge
theory with $n_f$ light flavors. These form factors contribute to both
quark-antiquark and gluon-gluon initiated processes involving spin-2 particle
in the hadronic reactions at the LHC. We have studied the structure of infrared
singularities in these form factors up to three loop level using Sudakov
integro-differential equation and found that the anomalous dimensions
originating from soft and collinear regions of the loop integrals coincide with
those of the electroweak vector boson and Higgs form factors confirming the
universality of the infrared singularities in QCD amplitudes.
| [
{
"created": "Thu, 20 Aug 2015 16:52:56 GMT",
"version": "v1"
}
] | 2016-01-27 | [
[
"Ahmed",
"Taushif",
""
],
[
"Das",
"Goutam",
""
],
[
"Mathews",
"Prakash",
""
],
[
"Rana",
"Narayan",
""
],
[
"Ravindran",
"V.",
""
]
] | Spin-2 fields are often candidates in physics beyond the Standard Model namely the models with extra-dimensions where spin-2 Kaluza-Klein gravitons couple to the fields of the SM. Also, in the context of Higgs searches, spin-2 fields have been studied as an alternative to the scalar Higgs boson. In this article, we present the complete three loop QCD radiative corrections to the spin-2 quark-antiquark and spin-2 gluon-gluon form factors in SU(N) gauge theory with $n_f$ light flavors. These form factors contribute to both quark-antiquark and gluon-gluon initiated processes involving spin-2 particle in the hadronic reactions at the LHC. We have studied the structure of infrared singularities in these form factors up to three loop level using Sudakov integro-differential equation and found that the anomalous dimensions originating from soft and collinear regions of the loop integrals coincide with those of the electroweak vector boson and Higgs form factors confirming the universality of the infrared singularities in QCD amplitudes. |
2101.00461 | Marat Siddikov Ilfatovich | Marat Siddikov, Iv\'an Schmidt | Strangeness production in high-multiplicity events | 12 pages, 6 figures. This paper is a sequel to our earlier
publications arXiv:1910.13579, arXiv:2003.13768, arXiv:2008.12446 and
arXiv:2012.08284 dedicated to multiplicity dependence of high energy
production cross-sections | Phys. Rev. D 104, 016024 (2021) | 10.1103/PhysRevD.104.016024 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this paper we analyze in detail the production of strangeness in
proton-proton collisions in the kinematics of large transverse momenta $p_{T}$
of produced hadrons. Using the color dipole framework, we estimated the
production cross-sections for kaons, and demonstrated that the shapes of the
$p_{T}$-dependence are in agreement with available experimental data. We also
analyzed the self-normalized yields of strange hadrons as a function of
multiplicity of co-produced hadrons, and found that the predictions are in
agreement with the faster-than-linear growth seen in experimental data. Our
description is largely parameter-free and complements our previous studies
dedicated to the explanation of multiplicity enhancement of quarkonia, as well
as $D$- and $B$-mesons.
| [
{
"created": "Sat, 2 Jan 2021 14:56:05 GMT",
"version": "v1"
}
] | 2021-08-04 | [
[
"Siddikov",
"Marat",
""
],
[
"Schmidt",
"Iván",
""
]
] | In this paper we analyze in detail the production of strangeness in proton-proton collisions in the kinematics of large transverse momenta $p_{T}$ of produced hadrons. Using the color dipole framework, we estimated the production cross-sections for kaons, and demonstrated that the shapes of the $p_{T}$-dependence are in agreement with available experimental data. We also analyzed the self-normalized yields of strange hadrons as a function of multiplicity of co-produced hadrons, and found that the predictions are in agreement with the faster-than-linear growth seen in experimental data. Our description is largely parameter-free and complements our previous studies dedicated to the explanation of multiplicity enhancement of quarkonia, as well as $D$- and $B$-mesons. |
1803.07079 | Pier Francesco Monni | Christian W. Bauer and Pier Francesco Monni | A numerical formulation of resummation in effective field theory | 47 pages | null | 10.1007/JHEP02(2019)185 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this article we show how the resummation of infrared and collinear
logarithms within Soft-Collinear Effective Theory (SCET) can be formulated in a
way that makes it suitable for a Monte-Carlo implementation. This is done by
applying the techniques developed for automated resummation using the branching
formalism, which have resulted in the general resummation approach CAESAR/ARES.
This work builds a connection between the two resummation approaches, and paves
the way to automated resummation in SCET. As a case study we consider the
resummation of the thrust distribution in electron-positron collisions at
next-to-leading logarithm (NLL). However, the results presented here are easily
generalizable to more complicated observables and processes as well as to
higher orders in the logarithmic accuracy.
| [
{
"created": "Mon, 19 Mar 2018 18:00:02 GMT",
"version": "v1"
}
] | 2019-03-27 | [
[
"Bauer",
"Christian W.",
""
],
[
"Monni",
"Pier Francesco",
""
]
] | In this article we show how the resummation of infrared and collinear logarithms within Soft-Collinear Effective Theory (SCET) can be formulated in a way that makes it suitable for a Monte-Carlo implementation. This is done by applying the techniques developed for automated resummation using the branching formalism, which have resulted in the general resummation approach CAESAR/ARES. This work builds a connection between the two resummation approaches, and paves the way to automated resummation in SCET. As a case study we consider the resummation of the thrust distribution in electron-positron collisions at next-to-leading logarithm (NLL). However, the results presented here are easily generalizable to more complicated observables and processes as well as to higher orders in the logarithmic accuracy. |
1608.06267 | Vannia Gonz\'alez-Mac\'ias Dr | Vannia Gonz\'alez-Mac\'ias, Jos\'e Illana, Jos\'e Wudka | Dark matter and the neutrino portal paradigm | "To be published in Journal of Physics Conference Series (IOP). Joint
Proceedings of the XV Mexican Workshop on Particles and Fields & the XXX
Annual Meeting of the Division of Particles and Fields of the Mexican
Physical Society" | null | 10.1088/1742-6596/761/1/012082 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | A simple extension of the Standard Model (SM) that provides an explicit
realization of the dark-matter (DM) neutrino-portal paradigm is presented. The
leading interactions between the dark sector, containing scalars and relic
fermions, and the SM involve neutrinos. This model meets all observational
constraints.
| [
{
"created": "Mon, 22 Aug 2016 19:17:34 GMT",
"version": "v1"
}
] | 2016-11-23 | [
[
"González-Macías",
"Vannia",
""
],
[
"Illana",
"José",
""
],
[
"Wudka",
"José",
""
]
] | A simple extension of the Standard Model (SM) that provides an explicit realization of the dark-matter (DM) neutrino-portal paradigm is presented. The leading interactions between the dark sector, containing scalars and relic fermions, and the SM involve neutrinos. This model meets all observational constraints. |
1712.05433 | Sebasti\'an Felipe Mantilla Serrano | Carlos E. Diaz, S. F. Mantilla, R. Martinez | Radiative neutrino masses with forbidden seesaw mechanism in an abelian
extension of the Standard Model | 6 pages, 2 figures, 2 tables | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The seesaw mechanism is the preferred methodology to obtain light neutrino
masses by the introduction of a Majorana mass matrix. Moreover, radiative
corrections can be done in order to improve the predictions of the model.
However, when such a Majorana mass has no inverse, radiative corrections turn
out as the only mechanism to get massive neutrinos. In this letter, it is shown
a nonuniversal abelian extension $\mathrm{U(1)}_{X}$ of the Standard Model in
which neutrinos acquire masses completely by radiative corrections through
one-loop self-energies involving heavier right-handed neutrinos. Moreover, one
right-handed neutrino also gets mass through radiative corrections involving
Majorana fermions. Finally, some limit cases are drafted depending on the
hierarchy among vacuum expectation values and Majorana masses.
| [
{
"created": "Thu, 14 Dec 2017 20:00:42 GMT",
"version": "v1"
},
{
"created": "Thu, 4 Jan 2018 04:51:36 GMT",
"version": "v2"
},
{
"created": "Fri, 9 Feb 2018 01:23:02 GMT",
"version": "v3"
}
] | 2018-02-12 | [
[
"Diaz",
"Carlos E.",
""
],
[
"Mantilla",
"S. F.",
""
],
[
"Martinez",
"R.",
""
]
] | The seesaw mechanism is the preferred methodology to obtain light neutrino masses by the introduction of a Majorana mass matrix. Moreover, radiative corrections can be done in order to improve the predictions of the model. However, when such a Majorana mass has no inverse, radiative corrections turn out as the only mechanism to get massive neutrinos. In this letter, it is shown a nonuniversal abelian extension $\mathrm{U(1)}_{X}$ of the Standard Model in which neutrinos acquire masses completely by radiative corrections through one-loop self-energies involving heavier right-handed neutrinos. Moreover, one right-handed neutrino also gets mass through radiative corrections involving Majorana fermions. Finally, some limit cases are drafted depending on the hierarchy among vacuum expectation values and Majorana masses. |
hep-ph/9604343 | Kyriakos Tamvakis | K. Tamvakis (CERN) | GUTs with Exclusively Delta-B=1, Delta-L=0 R-Parity Violation | 8 pages, one figure | Phys.Lett. B382 (1996) 251-256 | 10.1016/0370-2693(96)00679-X | CERN-TH/96-96 | hep-ph | null | We study $R$-parity violation in the framework of GUTs, focusing on the case
that $R$-parity is broken exclusively through $\Delta B=1$, $\Delta L=0$
effective interactions. We construct two such models, an $SU(5)$
and an $SU(5)\times U(1)_{X}$ model, in which $R$-parity breaking is induced
through interactions with extra supermassive fields. The presence of only the
Baryon Number violating operators ${d^c}{d^c}{u^c}$ requires an asymmetry
between quarks and leptons, which is achieved either by virtue of the Higgs
representations used or by modifications in the matter multiplets. The latter
possibility is realized in the second of the above models, where the
left-handed leptons have been removed from the representation in which they
normaly cohabit with the right-handed up quarks and enter as a combination of
the isodoublets in $(\bf {{\overline{5}},-3})$ and $(\bf {5,-2})$
representations. In both models the particle content below the GUT scale is
unaffected by the introduced $R$-parity breaking sector.
| [
{
"created": "Wed, 17 Apr 1996 09:57:52 GMT",
"version": "v1"
}
] | 2016-09-01 | [
[
"Tamvakis",
"K.",
"",
"CERN"
]
] | We study $R$-parity violation in the framework of GUTs, focusing on the case that $R$-parity is broken exclusively through $\Delta B=1$, $\Delta L=0$ effective interactions. We construct two such models, an $SU(5)$ and an $SU(5)\times U(1)_{X}$ model, in which $R$-parity breaking is induced through interactions with extra supermassive fields. The presence of only the Baryon Number violating operators ${d^c}{d^c}{u^c}$ requires an asymmetry between quarks and leptons, which is achieved either by virtue of the Higgs representations used or by modifications in the matter multiplets. The latter possibility is realized in the second of the above models, where the left-handed leptons have been removed from the representation in which they normaly cohabit with the right-handed up quarks and enter as a combination of the isodoublets in $(\bf {{\overline{5}},-3})$ and $(\bf {5,-2})$ representations. In both models the particle content below the GUT scale is unaffected by the introduced $R$-parity breaking sector. |
1805.11109 | Benjamin Elder | Benjamin T. Elder and Jesse Thaler | Aspects of Track-Assisted Mass | 35+17 pages, 22 figures; v3: improvements to calculation and
presentation to appear in JHEP | null | 10.1007/JHEP03(2019)104 | MIT-CTP/5021 | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Track-assisted mass is a proxy for jet mass that only uses direction
information from charged particles, allowing it to be measured at the Large
Hadron Collider with very fine angular resolution. In this paper, we introduce
a generalization of track-assisted mass and analyze its performance in both
parton shower generators and resummed calculations. For the original
track-assisted mass, the track-only mass is rescaled by the charged energy
fraction of the jet. In our generalization, the rescaling factor includes both
per-jet and ensemble-averaged information, facilitating a closer correspondence
to ordinary jet mass. Using the track function formalism in electron-positron
collisions, we calculate the spectrum of generalized track-assisted mass to
next-to-leading-logarithmic order with leading-order matching. These resummed
calculations provide theoretical insight into the close correspondence between
track-assisted mass and ordinary jet mass. With the growing importance of jet
grooming algorithms, we also calculate track-assisted mass on soft-drop groomed
jets.
| [
{
"created": "Mon, 28 May 2018 18:00:55 GMT",
"version": "v1"
},
{
"created": "Tue, 12 Jun 2018 16:02:52 GMT",
"version": "v2"
},
{
"created": "Sat, 16 Mar 2019 20:25:52 GMT",
"version": "v3"
}
] | 2019-05-01 | [
[
"Elder",
"Benjamin T.",
""
],
[
"Thaler",
"Jesse",
""
]
] | Track-assisted mass is a proxy for jet mass that only uses direction information from charged particles, allowing it to be measured at the Large Hadron Collider with very fine angular resolution. In this paper, we introduce a generalization of track-assisted mass and analyze its performance in both parton shower generators and resummed calculations. For the original track-assisted mass, the track-only mass is rescaled by the charged energy fraction of the jet. In our generalization, the rescaling factor includes both per-jet and ensemble-averaged information, facilitating a closer correspondence to ordinary jet mass. Using the track function formalism in electron-positron collisions, we calculate the spectrum of generalized track-assisted mass to next-to-leading-logarithmic order with leading-order matching. These resummed calculations provide theoretical insight into the close correspondence between track-assisted mass and ordinary jet mass. With the growing importance of jet grooming algorithms, we also calculate track-assisted mass on soft-drop groomed jets. |
1308.5596 | Matthias Drews | Matthias Drews, Thomas Hell, Bertram Klein, Wolfram Weise | Thermodynamic phases and mesonic fluctuations in a chiral nucleon-meson
model | 10 pages, 11 figures; references added, discussions enlarged | Phys. Rev. D 88, 096011 (2013) | 10.1103/PhysRevD.88.096011 | null | hep-ph nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Studies of the QCD phase diagram must properly include nucleonic degrees of
freedom and their thermodynamics in the range of baryon chemical potentials
characteristic of nuclear matter. A useful framework for incorporating relevant
nuclear physics constraints in this context is a chiral nucleon-meson effective
Lagrangian. In the present paper, such a chiral nucleon-meson model is extended
with systematic inclusion of mesonic fluctuations using the functional
renormalization group approach. The resulting description of the nuclear
liquid-gas phase transition shows a remarkable agreement with three-loop
calculations based on in-medium chiral effective field theory. No signs of a
chiral first-order phase transition and its critical endpoint are found in the
region of applicability of the model, at least up to twice the density of
normal nuclear matter and at temperatures T<100 MeV. Fluctuations close to the
critical point of the first-order liquid-gas transition are also examined with
a detailed study of the chiral susceptibility.
| [
{
"created": "Mon, 26 Aug 2013 14:25:10 GMT",
"version": "v1"
},
{
"created": "Tue, 19 Nov 2013 13:11:08 GMT",
"version": "v2"
}
] | 2014-01-27 | [
[
"Drews",
"Matthias",
""
],
[
"Hell",
"Thomas",
""
],
[
"Klein",
"Bertram",
""
],
[
"Weise",
"Wolfram",
""
]
] | Studies of the QCD phase diagram must properly include nucleonic degrees of freedom and their thermodynamics in the range of baryon chemical potentials characteristic of nuclear matter. A useful framework for incorporating relevant nuclear physics constraints in this context is a chiral nucleon-meson effective Lagrangian. In the present paper, such a chiral nucleon-meson model is extended with systematic inclusion of mesonic fluctuations using the functional renormalization group approach. The resulting description of the nuclear liquid-gas phase transition shows a remarkable agreement with three-loop calculations based on in-medium chiral effective field theory. No signs of a chiral first-order phase transition and its critical endpoint are found in the region of applicability of the model, at least up to twice the density of normal nuclear matter and at temperatures T<100 MeV. Fluctuations close to the critical point of the first-order liquid-gas transition are also examined with a detailed study of the chiral susceptibility. |
2112.08992 | Jan Tristram Acu\~na | Jan Tristram Acu\~na, Patrick Stengel, Piero Ullio | A Minimal Dark Matter Model for Muon g-2 with Scalar Lepton Partners up
to the TeV Scale | 27 pages, 21 figures, 1 table | null | null | null | hep-ph astro-ph.CO | http://creativecommons.org/licenses/by/4.0/ | The E989 experiment at the Fermi National Laboratory reported a 4.2$\sigma$
discrepancy between the measured magnetic dipole moment of the muon, and its
prediction in the Standard Model (SM). In this study, we address the anomaly by
considering a minimal and generic extension to the SM which also provides for a
dark matter (DM) candidate. The extra states in this framework are: a SM
singlet Majorana fermion, referred to as the Bino, playing the role of DM; and
muonic scalars, referred to as sleptons. The couplings between the sleptons, SM
muons and the Bino can account for the muon $g-2$ anomaly if the scalar muon
partners, or smuons, mix chirality. On the other hand, the DM relic density is
satisfied primarily through coannihilation effects involving the Bino and the
lighter sleptons. The viable parameter space of our model includes regions with
relatively light coannihilating particles, similar to what has been found in
previous scans of the Minimal Supersymmetric Standard Model (MSSM). Relaxing
the assumption of minimal flavor violation typically assumed in the MSSM, we
see that scenarios with sizable smuon mixing and large mass splittings between
the smuons can satisfy both the muon $g-2$ anomaly and the DM relic density for
coannihilating particle masses up to and beyond the TeV scale. When we specify
the origin of the left-right smuon mixing to be trilinear couplings between the
smuons and the SM Higgs boson, the constraints on these scenarios arising from
perturbative unitarity and electroweak vacuum stability confine the
coannihilating particle masses to be $\lesssim$ 1 TeV. We demonstrate that next
generation direct detection experiments are only marginally sensitive to the
viable parameter space of our model and, thus, a future lepton collider could
be the essential probe necessary to distinguish our model from other BSM
solutions to the muon $g-2$ anomaly.
| [
{
"created": "Thu, 16 Dec 2021 16:12:02 GMT",
"version": "v1"
}
] | 2021-12-17 | [
[
"Acuña",
"Jan Tristram",
""
],
[
"Stengel",
"Patrick",
""
],
[
"Ullio",
"Piero",
""
]
] | The E989 experiment at the Fermi National Laboratory reported a 4.2$\sigma$ discrepancy between the measured magnetic dipole moment of the muon, and its prediction in the Standard Model (SM). In this study, we address the anomaly by considering a minimal and generic extension to the SM which also provides for a dark matter (DM) candidate. The extra states in this framework are: a SM singlet Majorana fermion, referred to as the Bino, playing the role of DM; and muonic scalars, referred to as sleptons. The couplings between the sleptons, SM muons and the Bino can account for the muon $g-2$ anomaly if the scalar muon partners, or smuons, mix chirality. On the other hand, the DM relic density is satisfied primarily through coannihilation effects involving the Bino and the lighter sleptons. The viable parameter space of our model includes regions with relatively light coannihilating particles, similar to what has been found in previous scans of the Minimal Supersymmetric Standard Model (MSSM). Relaxing the assumption of minimal flavor violation typically assumed in the MSSM, we see that scenarios with sizable smuon mixing and large mass splittings between the smuons can satisfy both the muon $g-2$ anomaly and the DM relic density for coannihilating particle masses up to and beyond the TeV scale. When we specify the origin of the left-right smuon mixing to be trilinear couplings between the smuons and the SM Higgs boson, the constraints on these scenarios arising from perturbative unitarity and electroweak vacuum stability confine the coannihilating particle masses to be $\lesssim$ 1 TeV. We demonstrate that next generation direct detection experiments are only marginally sensitive to the viable parameter space of our model and, thus, a future lepton collider could be the essential probe necessary to distinguish our model from other BSM solutions to the muon $g-2$ anomaly. |
1009.0905 | Patrick K. S. Vaudrevange | Hyun Min Lee, Stuart Raby, Michael Ratz, Graham G. Ross, Roland
Schieren, Kai Schmidt-Hoberg, Patrick K.S. Vaudrevange | A unique Z_4^R symmetry for the MSSM | 6 pages | Phys.Lett.B694:491-495,2011 | 10.1016/j.physletb.2010.10.038 | TUM-HEP 770/10; LMU-ASC 64/10; OHSTPY-HEP-T-10-003;
CERN-PH-TH/2010-193; OUTP-10-24P | hep-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We consider the possible anomaly free Abelian discrete symmetries of the MSSM
that forbid the mu-term at perturbative order. Allowing for anomaly
cancellation via the Green-Schwarz mechanism we identify discrete R-symmetries
as the only possibility and prove that there is a unique Z_4^R symmetry that
commutes with SO(10). We argue that non-perturbative effects will generate a
mu-term of electroweak order thus solving the mu-problem. The non-perturbative
effects break the Z_4^R symmetry leaving an exact Z_2 matter parity. As a
result dimension four baryon- and lepton-number violating operators are absent
while, at the non-perturbative level, dimension five baryon- and lepton-number
violating operators get induced but are highly suppressed so that the nucleon
decay rate is well within present bounds.
| [
{
"created": "Sun, 5 Sep 2010 10:26:04 GMT",
"version": "v1"
},
{
"created": "Tue, 28 Sep 2010 14:28:56 GMT",
"version": "v2"
}
] | 2011-02-25 | [
[
"Lee",
"Hyun Min",
""
],
[
"Raby",
"Stuart",
""
],
[
"Ratz",
"Michael",
""
],
[
"Ross",
"Graham G.",
""
],
[
"Schieren",
"Roland",
""
],
[
"Schmidt-Hoberg",
"Kai",
""
],
[
"Vaudrevange",
"Patrick K. S.",
""
]
] | We consider the possible anomaly free Abelian discrete symmetries of the MSSM that forbid the mu-term at perturbative order. Allowing for anomaly cancellation via the Green-Schwarz mechanism we identify discrete R-symmetries as the only possibility and prove that there is a unique Z_4^R symmetry that commutes with SO(10). We argue that non-perturbative effects will generate a mu-term of electroweak order thus solving the mu-problem. The non-perturbative effects break the Z_4^R symmetry leaving an exact Z_2 matter parity. As a result dimension four baryon- and lepton-number violating operators are absent while, at the non-perturbative level, dimension five baryon- and lepton-number violating operators get induced but are highly suppressed so that the nucleon decay rate is well within present bounds. |
hep-ph/0611192 | Mingzhe Li | Mingzhe Li, Jun-Qing Xia, Hong Li, and Xinmin Zhang | Cosmological CPT Violation, Baryon/Leptogenesis and CMB Polarization | The version appears in PLB | Phys.Lett.B651:357-362,2007 | 10.1016/j.physletb.2007.06.050 | null | hep-ph astro-ph hep-th | null | In this paper we study the cosmological CPT-violation and its implications in
baryo/leptogenesis and CMB polarization. We propose specifically a variant of
the models of gravitational leptogenesis. By performing a global analysis with
the Markov Chain Monte Carlo (MCMC) method, we find the current CMB
polarization observations from the three-year WMAP (WMAP3) and the 2003 flight
of BOOMERANG (B03) data provide a weak evidence for our model. However to
verify and especially exclude this type of mechanism for baryo/leptogenesis
with cosmological CPT-violation, the future measurements on CMB polarization
from PLANCK and CMBpol are necessary.
| [
{
"created": "Tue, 14 Nov 2006 16:03:40 GMT",
"version": "v1"
},
{
"created": "Fri, 27 Jul 2007 14:25:56 GMT",
"version": "v2"
}
] | 2008-11-26 | [
[
"Li",
"Mingzhe",
""
],
[
"Xia",
"Jun-Qing",
""
],
[
"Li",
"Hong",
""
],
[
"Zhang",
"Xinmin",
""
]
] | In this paper we study the cosmological CPT-violation and its implications in baryo/leptogenesis and CMB polarization. We propose specifically a variant of the models of gravitational leptogenesis. By performing a global analysis with the Markov Chain Monte Carlo (MCMC) method, we find the current CMB polarization observations from the three-year WMAP (WMAP3) and the 2003 flight of BOOMERANG (B03) data provide a weak evidence for our model. However to verify and especially exclude this type of mechanism for baryo/leptogenesis with cosmological CPT-violation, the future measurements on CMB polarization from PLANCK and CMBpol are necessary. |
0810.5762 | Pran Nath | Daniel Feldman, Zuowei Liu, and Pran Nath | PAMELA Positron Excess as a Signal from the Hidden Sector | 9 pages,3 figures; Breit-Wigner enhancement emphasized; published in
PRD | Phys.Rev.D79:063509,2009 | 10.1103/PhysRevD.79.063509 | NUB-3262 and YITP-SB-08-50 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The recent positron excess observed in the PAMELA satellite experiment
strengthens previous experimental findings. We give here an analysis of this
excess in the framework of the Stueckelberg extension of the standard model
which includes an extra $U(1)_X$ gauge field and matter in the hidden sector.
Such matter can produce the right amount of dark matter consistent with the
WMAP constraints. Assuming the hidden sector matter to be Dirac fermions it is
shown that their annihilation can produce the positron excess with the right
positron energy dependence seen in the HEAT, AMS and the PAMELA experiments.
Further test of the proposed model can come at the Large Hadron Collider. The
predictions of the $\bar p/p$ flux ratio also fit the data.
| [
{
"created": "Fri, 31 Oct 2008 19:47:59 GMT",
"version": "v1"
},
{
"created": "Sat, 1 Nov 2008 18:39:01 GMT",
"version": "v2"
},
{
"created": "Sat, 14 Mar 2009 00:59:01 GMT",
"version": "v3"
}
] | 2009-03-24 | [
[
"Feldman",
"Daniel",
""
],
[
"Liu",
"Zuowei",
""
],
[
"Nath",
"Pran",
""
]
] | The recent positron excess observed in the PAMELA satellite experiment strengthens previous experimental findings. We give here an analysis of this excess in the framework of the Stueckelberg extension of the standard model which includes an extra $U(1)_X$ gauge field and matter in the hidden sector. Such matter can produce the right amount of dark matter consistent with the WMAP constraints. Assuming the hidden sector matter to be Dirac fermions it is shown that their annihilation can produce the positron excess with the right positron energy dependence seen in the HEAT, AMS and the PAMELA experiments. Further test of the proposed model can come at the Large Hadron Collider. The predictions of the $\bar p/p$ flux ratio also fit the data. |
1711.07365 | Hiroshi Okada | Cheng-Wei Chiang, Hiroshi Okada | A simple model for explaining muon-related anomalies and dark matter | 19 pages, 1 table, 4 figures: version accepted for publication in
Journal of Modern Physics A | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We propose a model to explain several muon-related experimental anomalies and
the abundance of dark matter. We introduce an vector-like exotic lepton that
form an iso-doublet and three right-handed Majorana fermions as an iso-singlet.
A real/complex scalar field is added as a dark matter candidate. We impose a
global $U(1)_ \mu$ symmetry under which fields associated with the SM muon are
charged. To stabilize the dark matter, we impose a $Z_2$ (or $Z_3$) symmetry
under which the exotic lepton doublet and the real (or complex) scalar field
are charged. We find that the model can simultaneously explain the muon
anomalous magnetic dipole moment and the dark matter relic density in no
conflict with any lepton flavor-violating/conserving observables, with some
details depending upon whether the scalar field is real or complex. Besides, we
extend the framework to the quark sector in a way similar to the lepton sector,
and find that the recent anomalies associated with the $b \to s \mu^+ \mu^-$
transition can also be accommodated while satisfying constraints such as the
$B_{s(d)} \to \mu^+ \mu^-$ decays and neutral meson mixings.
| [
{
"created": "Mon, 20 Nov 2017 15:17:07 GMT",
"version": "v1"
},
{
"created": "Sat, 23 Dec 2017 11:16:02 GMT",
"version": "v2"
},
{
"created": "Tue, 18 Jun 2019 10:28:48 GMT",
"version": "v3"
}
] | 2019-06-19 | [
[
"Chiang",
"Cheng-Wei",
""
],
[
"Okada",
"Hiroshi",
""
]
] | We propose a model to explain several muon-related experimental anomalies and the abundance of dark matter. We introduce an vector-like exotic lepton that form an iso-doublet and three right-handed Majorana fermions as an iso-singlet. A real/complex scalar field is added as a dark matter candidate. We impose a global $U(1)_ \mu$ symmetry under which fields associated with the SM muon are charged. To stabilize the dark matter, we impose a $Z_2$ (or $Z_3$) symmetry under which the exotic lepton doublet and the real (or complex) scalar field are charged. We find that the model can simultaneously explain the muon anomalous magnetic dipole moment and the dark matter relic density in no conflict with any lepton flavor-violating/conserving observables, with some details depending upon whether the scalar field is real or complex. Besides, we extend the framework to the quark sector in a way similar to the lepton sector, and find that the recent anomalies associated with the $b \to s \mu^+ \mu^-$ transition can also be accommodated while satisfying constraints such as the $B_{s(d)} \to \mu^+ \mu^-$ decays and neutral meson mixings. |
1609.06205 | Sung Hak Lim | Chengcheng Han, Doojin Kim, Minho Kim, Kyoungchul Kong, Sung Hak Lim,
Myeonghun Park | Identifying a new particle with jet substructures | 36 pages, 11 figures, published in JHEP | JHEP 01 (2017) 027 | 10.1007/JHEP01(2017)027 | CTPU-16-19, IPMU16-0133, PITT-PACC-1608, CERN-TH-2016-218 | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We investigate a potential of measuring properties of a heavy resonance X,
exploiting jet substructure techniques. Motivated by heavy higgs boson
searches, we focus on the decays of X into a pair of (massive) electroweak
gauge bosons. More specifically, we consider a hadronic Z boson, which makes it
possible to determine properties of X at an earlier stage. For $m_X$ of O(1)
TeV, two quarks from a Z boson would be captured as a "merged jet" in a
significant fraction of events. The use of the merged jet enables us to
consider a Z-induced jet as a reconstructed object without any combinatorial
ambiguity. We apply a conventional jet substructure method to extract
four-momenta of subjets from a merged jet. We find that jet substructure
procedures may enhance features in some kinematic observables formed with
subjets. Subjet momenta are fed into the matrix element associated with a given
hypothesis on the nature of X, which is further processed to construct a matrix
element method (MEM)-based observable. For both moderately and highly boosted Z
bosons, we demonstrate that the MEM with current jet substructure techniques
can be a very powerful discriminator in identifying the physics nature of X. We
also discuss effects from choosing different jet sizes for merged jets and
jet-grooming parameters upon the MEM analyses.
| [
{
"created": "Tue, 20 Sep 2016 14:55:30 GMT",
"version": "v1"
},
{
"created": "Thu, 16 Mar 2017 02:10:05 GMT",
"version": "v2"
}
] | 2017-03-17 | [
[
"Han",
"Chengcheng",
""
],
[
"Kim",
"Doojin",
""
],
[
"Kim",
"Minho",
""
],
[
"Kong",
"Kyoungchul",
""
],
[
"Lim",
"Sung Hak",
""
],
[
"Park",
"Myeonghun",
""
]
] | We investigate a potential of measuring properties of a heavy resonance X, exploiting jet substructure techniques. Motivated by heavy higgs boson searches, we focus on the decays of X into a pair of (massive) electroweak gauge bosons. More specifically, we consider a hadronic Z boson, which makes it possible to determine properties of X at an earlier stage. For $m_X$ of O(1) TeV, two quarks from a Z boson would be captured as a "merged jet" in a significant fraction of events. The use of the merged jet enables us to consider a Z-induced jet as a reconstructed object without any combinatorial ambiguity. We apply a conventional jet substructure method to extract four-momenta of subjets from a merged jet. We find that jet substructure procedures may enhance features in some kinematic observables formed with subjets. Subjet momenta are fed into the matrix element associated with a given hypothesis on the nature of X, which is further processed to construct a matrix element method (MEM)-based observable. For both moderately and highly boosted Z bosons, we demonstrate that the MEM with current jet substructure techniques can be a very powerful discriminator in identifying the physics nature of X. We also discuss effects from choosing different jet sizes for merged jets and jet-grooming parameters upon the MEM analyses. |
hep-ph/0504253 | Yue Chongxing | Chong-Xing Yue, Wei Wang, Zheng-Jun Zong, and Feng Zhang | Probing signals of the littlest Higgs model via the $WW$ fusion
processes at the high energy $e^{+}e^{-}$ collider | 22 pages, 9 figures; references added, some typos corrected; version
to be published in Eur.Phys.J.C | Eur.Phys.J.C42:331-339,2005 | 10.1140/epjc/s2005-02313-y | null | hep-ph | null | In the framework of the littlest Higgs($LH$) model, we consider the processes
$e^{+}e^{-}\to\nu\bar{\nu}H^{0}$ and $e^{+}e^{-}\to
W^{*}W^{*}\nu\bar{\nu}\to\nu\bar{\nu}t\bar{t}$, and calculate the contributions
of new particles to the cross sections of these processes in the future high
energy $e^{+}e^{-}$ collider($ILC$) with $\sqrt{S}=1TeV$. We find that, with
reasonable values of the free parameters, the deviations of the cross sections
for the processes $e^{+}e^{-}\to\nu\bar{\nu}H^{0}$ from its $SM$ value might be
comparable to the future $ILC$ measurement precision. The contributions of the
light Higgs boson $H^0 $ to the process $e^{+}e^{-}\to
W^{*}W^{*}\nu\bar{\nu}\to\nu\bar{\nu}t\bar{t}$ are significant large in all of
the parameter space preferred by the electroweak precision data, which might be
detected in the future $ILC$ experiments. However, the contributions of the new
gauge bosons $B_{H}$ and $Z_{H}$ to this process are very small.
| [
{
"created": "Wed, 27 Apr 2005 08:11:22 GMT",
"version": "v1"
},
{
"created": "Mon, 6 Jun 2005 07:49:47 GMT",
"version": "v2"
}
] | 2009-01-07 | [
[
"Yue",
"Chong-Xing",
""
],
[
"Wang",
"Wei",
""
],
[
"Zong",
"Zheng-Jun",
""
],
[
"Zhang",
"Feng",
""
]
] | In the framework of the littlest Higgs($LH$) model, we consider the processes $e^{+}e^{-}\to\nu\bar{\nu}H^{0}$ and $e^{+}e^{-}\to W^{*}W^{*}\nu\bar{\nu}\to\nu\bar{\nu}t\bar{t}$, and calculate the contributions of new particles to the cross sections of these processes in the future high energy $e^{+}e^{-}$ collider($ILC$) with $\sqrt{S}=1TeV$. We find that, with reasonable values of the free parameters, the deviations of the cross sections for the processes $e^{+}e^{-}\to\nu\bar{\nu}H^{0}$ from its $SM$ value might be comparable to the future $ILC$ measurement precision. The contributions of the light Higgs boson $H^0 $ to the process $e^{+}e^{-}\to W^{*}W^{*}\nu\bar{\nu}\to\nu\bar{\nu}t\bar{t}$ are significant large in all of the parameter space preferred by the electroweak precision data, which might be detected in the future $ILC$ experiments. However, the contributions of the new gauge bosons $B_{H}$ and $Z_{H}$ to this process are very small. |
hep-ph/0501028 | Marcus Bleicher | J. Ruppert (Duke U.), C. Rahmede (Frankfurt U., SISSA), M. Bleicher
(Frankfurt U.) | Determination of the Fundamental Scale of Gravity and the Number of
Space-time Dimensions from High Energetic Particle Interactions | 3 pages, 2 figures | Phys.Lett. B608 (2005) 240-243 | 10.1016/j.physletb.2005.01.013 | null | hep-ph | null | Within the ADD-model, we elaborate an idea by Vacavant and Hinchliffe and
show quantitatively how to determine the fundamental scale of TeV-gravity and
the number of compactified extra dimensions from data at LHC. We demonstrate
that the ADD-model leads to strong correlations between the missing $E_T$ in
gravitons at different center of mass energies. This correlation puts strong
constraints on this model for extra dimensions, if probed at $\sqrt{s}=5.5$ TeV
and $\sqrt{s}=14$ TeV at LHC.
| [
{
"created": "Wed, 5 Jan 2005 14:59:04 GMT",
"version": "v1"
}
] | 2009-11-11 | [
[
"Ruppert",
"J.",
"",
"Duke U."
],
[
"Rahmede",
"C.",
"",
"Frankfurt U., SISSA"
],
[
"Bleicher",
"M.",
"",
"Frankfurt U."
]
] | Within the ADD-model, we elaborate an idea by Vacavant and Hinchliffe and show quantitatively how to determine the fundamental scale of TeV-gravity and the number of compactified extra dimensions from data at LHC. We demonstrate that the ADD-model leads to strong correlations between the missing $E_T$ in gravitons at different center of mass energies. This correlation puts strong constraints on this model for extra dimensions, if probed at $\sqrt{s}=5.5$ TeV and $\sqrt{s}=14$ TeV at LHC. |
0807.2324 | Bingsong Zou | F.X.Wei and B.S.Zou | Single spin asymmetry and five-quark components of the proton | 12 pages, 3 figures | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We examine the single-spin asymmetry (SSA) caused by the five-quark
components of the proton for semi-inclusive electroproduction of charged pions
in deep-inelastic scattering on a transversely polarized hydrogen target. The
large SSA is considered to have close relation with quark orbital motion in the
proton and suggests that the quark orbital angular momentum is nonzero. For the
five-quark $qqqq\bar{q}$ components of the proton, the lowest configurations
with $qqqq$ system orbitally excited and the $\bar{q}$ in the ground state
would give spin-orbit correlations naturally for the quarks in a polarized
proton. We show that based on the basic reaction $\gamma q \to \pi q'$, the
orbital-spin coupling of the probed quarks in the five-quark configuration
leads to the single-spin asymmetry consistent with recent experiment results.
| [
{
"created": "Tue, 15 Jul 2008 09:18:20 GMT",
"version": "v1"
}
] | 2008-07-16 | [
[
"Wei",
"F. X.",
""
],
[
"Zou",
"B. S.",
""
]
] | We examine the single-spin asymmetry (SSA) caused by the five-quark components of the proton for semi-inclusive electroproduction of charged pions in deep-inelastic scattering on a transversely polarized hydrogen target. The large SSA is considered to have close relation with quark orbital motion in the proton and suggests that the quark orbital angular momentum is nonzero. For the five-quark $qqqq\bar{q}$ components of the proton, the lowest configurations with $qqqq$ system orbitally excited and the $\bar{q}$ in the ground state would give spin-orbit correlations naturally for the quarks in a polarized proton. We show that based on the basic reaction $\gamma q \to \pi q'$, the orbital-spin coupling of the probed quarks in the five-quark configuration leads to the single-spin asymmetry consistent with recent experiment results. |
2308.15380 | Amitayus Banik | Amitayus Banik and Manuel Drees | Non-thermal WIMP Production from Higher Order Moduli Decay | 43 pages, 24 figures, 2 appendices; v2: figures and references
updated, two footnotes added; v3: typos corrected, matches version accepted
for publication in JCAP | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In a non-standard cosmological scenario, heavy, long-lived particles, which
we call moduli, dominate the energy density prior to Big Bang Nucleosynthesis.
Weakly Interacting Massive Particles (WIMPs) may be produced non-thermally from
moduli decays. The final relic abundance then depends on additional parameters
such as the branching ratio of moduli to WIMPs and the modulus mass. This is of
interest for WIMP candidates, such as a bino-like neutralino, where thermal
production in standard cosmology leads to an overdensity. Previous works have
shown that the correct dark matter (DM) relic density can then still be
obtained if the moduli, with mass less than $10^{7}$ GeV, decay to WIMPs with a
branching ratio of less than $10^{-4}$. This upper bound could easily be
violated once higher order corrections, involving final states with more than
two particles, are included. We compute the branching ratios of three- and
four-body decays of a modulus into final states involving two DM particles for
general couplings. We then apply these expressions to sparticle production
within the Minimal Supersymmetric Standard Model (MSSM) with neutralino DM. We
find that this upper bound on the branching ratio can be satisfied in
simplified models through an appropriate choice of as yet undetermined
couplings. However, in the MSSM, it requires sparticle masses to be very close
to half the modulus mass, in contrast to the idea of weak-scale supersymmetry.
| [
{
"created": "Tue, 29 Aug 2023 15:18:06 GMT",
"version": "v1"
},
{
"created": "Wed, 6 Sep 2023 07:29:45 GMT",
"version": "v2"
},
{
"created": "Tue, 12 Dec 2023 09:12:31 GMT",
"version": "v3"
}
] | 2023-12-13 | [
[
"Banik",
"Amitayus",
""
],
[
"Drees",
"Manuel",
""
]
] | In a non-standard cosmological scenario, heavy, long-lived particles, which we call moduli, dominate the energy density prior to Big Bang Nucleosynthesis. Weakly Interacting Massive Particles (WIMPs) may be produced non-thermally from moduli decays. The final relic abundance then depends on additional parameters such as the branching ratio of moduli to WIMPs and the modulus mass. This is of interest for WIMP candidates, such as a bino-like neutralino, where thermal production in standard cosmology leads to an overdensity. Previous works have shown that the correct dark matter (DM) relic density can then still be obtained if the moduli, with mass less than $10^{7}$ GeV, decay to WIMPs with a branching ratio of less than $10^{-4}$. This upper bound could easily be violated once higher order corrections, involving final states with more than two particles, are included. We compute the branching ratios of three- and four-body decays of a modulus into final states involving two DM particles for general couplings. We then apply these expressions to sparticle production within the Minimal Supersymmetric Standard Model (MSSM) with neutralino DM. We find that this upper bound on the branching ratio can be satisfied in simplified models through an appropriate choice of as yet undetermined couplings. However, in the MSSM, it requires sparticle masses to be very close to half the modulus mass, in contrast to the idea of weak-scale supersymmetry. |
hep-ph/0111005 | Erler | Jens Erler | Determinations of alpha(M_Z): Comparison and Prospects | 3 pages, Talk presented at the Workshop "The Future of High Energy
Physics" (Snowmass 2001) | eConf C010630 (2001) E3012 | null | UPR-965-T | hep-ph | null | I review and compare various techniques to obtain the value of the QED
coupling, alpha, at the Z pole. GigaZ precisions would require a much more
accurate determination than available today. A combination of the virtues of
current methods may help to achieve this goal.
| [
{
"created": "Wed, 31 Oct 2001 23:54:26 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Erler",
"Jens",
""
]
] | I review and compare various techniques to obtain the value of the QED coupling, alpha, at the Z pole. GigaZ precisions would require a much more accurate determination than available today. A combination of the virtues of current methods may help to achieve this goal. |
1010.4963 | Hiroshi Okada | Yasuhiro Daikoku, Hiroshi Okada, Takashi Toma | Seesaw Mechanism Confronting PAMELA in S_4 Flavor Symmetric Extra U(1)
Model | 7 pages, 1 table, no figures | null | null | KANAZAWA-10-08 | hep-ph astro-ph.HE | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study cosmic-ray anomaly observed by PAMELA based on E_6 inspired extra
U(1) model with S_4 flavor symmetry. In our model, the lightest flavon has very
long lifetime of O(10^18) second which is longer than the age of the universe,
but not long enough to explain the PAMELA result O(10^26) sec. Such a situation
could be avoidable by considering that the flavon is not the dominant component
of dark matters. However non-thermalizing the flavon is needed to obtain proper
relic density. This relates reheating temperature of the universe with seesaw
mass scale. If we assume this flavon is a particle decaying into positron (or
electron), the seesaw mass scale is constrained by reheating temperature. Thus
we find an interesting result that the allowed region is around O(10^12) GeV,
which is consistent with our original result.
| [
{
"created": "Sun, 24 Oct 2010 14:14:29 GMT",
"version": "v1"
}
] | 2010-10-26 | [
[
"Daikoku",
"Yasuhiro",
""
],
[
"Okada",
"Hiroshi",
""
],
[
"Toma",
"Takashi",
""
]
] | We study cosmic-ray anomaly observed by PAMELA based on E_6 inspired extra U(1) model with S_4 flavor symmetry. In our model, the lightest flavon has very long lifetime of O(10^18) second which is longer than the age of the universe, but not long enough to explain the PAMELA result O(10^26) sec. Such a situation could be avoidable by considering that the flavon is not the dominant component of dark matters. However non-thermalizing the flavon is needed to obtain proper relic density. This relates reheating temperature of the universe with seesaw mass scale. If we assume this flavon is a particle decaying into positron (or electron), the seesaw mass scale is constrained by reheating temperature. Thus we find an interesting result that the allowed region is around O(10^12) GeV, which is consistent with our original result. |
0911.1906 | Piotr Kotko | Piotr Kotko | Soft Matrix Elements in Non-local Chiral Quark Model | Presented in the poster session at The 2009 Europhysics Conference on
High Energy Physics, 16-22 July 2009 Krakow, Poland. To appear in Proceedings
of Science | PoS EPS-HEP2009:444,2009 | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Using non-local chiral quark model and currents satisfying Ward-Takahashi
identities we analyze Distribution Amplitudes (DA) of photon and pion-to-photon
Transition Distribution Amplitudes (TDA) in the low energy regime. Photon DA's
are calculated analytically up to twist-4 and reveal several interesting
features of photon structure. TDA's calculated in the present model satisfy
polynomiality condition. Normalization of vector TDA is fixed by the axial
anomaly. We also compute relevant form factors and compare them with existing
data. Axial form factor turns out to be much lower then the vector one, what
indeed is seen in the experimental data.
| [
{
"created": "Tue, 10 Nov 2009 13:43:09 GMT",
"version": "v1"
}
] | 2014-11-20 | [
[
"Kotko",
"Piotr",
""
]
] | Using non-local chiral quark model and currents satisfying Ward-Takahashi identities we analyze Distribution Amplitudes (DA) of photon and pion-to-photon Transition Distribution Amplitudes (TDA) in the low energy regime. Photon DA's are calculated analytically up to twist-4 and reveal several interesting features of photon structure. TDA's calculated in the present model satisfy polynomiality condition. Normalization of vector TDA is fixed by the axial anomaly. We also compute relevant form factors and compare them with existing data. Axial form factor turns out to be much lower then the vector one, what indeed is seen in the experimental data. |
0710.1474 | Xing-Hua Wu | Xin-Heng Guo, Ke-Wei Wei and Xing-Hua Wu | Strong decays of heavy baryons in Bethe-Salpeter formalism | 41 pages, 1 figure, LaTex2e, typos corrected | Phys.Rev.D77:036003,2008 | 10.1103/PhysRevD.77.036003 | null | hep-ph | null | In this paper we study the properties of diquarks (composed of $u$ and/or $d$
quarks) in the Bethe-Salpeter formalism under the covariant instantaneous
approximation. We calculate their BS wave functions and study their effective
interaction with the pion. Using the effective coupling constant among the
diquarks and the pion, in the heavy quark limit $m_Q\to\infty$, we calculate
the decay widths of $\Sigma_Q^{(*)}$ ($Q=c,b$) in the BS formalism under the
covariant instantaneous approximation and then give predictions of the decay
widths $\Gamma(\Sigma_b^{(*)}\to\Lambda_b+\pi)$.
| [
{
"created": "Mon, 8 Oct 2007 07:06:15 GMT",
"version": "v1"
},
{
"created": "Mon, 31 Dec 2007 03:02:28 GMT",
"version": "v2"
},
{
"created": "Tue, 19 Feb 2008 10:47:41 GMT",
"version": "v3"
}
] | 2008-11-26 | [
[
"Guo",
"Xin-Heng",
""
],
[
"Wei",
"Ke-Wei",
""
],
[
"Wu",
"Xing-Hua",
""
]
] | In this paper we study the properties of diquarks (composed of $u$ and/or $d$ quarks) in the Bethe-Salpeter formalism under the covariant instantaneous approximation. We calculate their BS wave functions and study their effective interaction with the pion. Using the effective coupling constant among the diquarks and the pion, in the heavy quark limit $m_Q\to\infty$, we calculate the decay widths of $\Sigma_Q^{(*)}$ ($Q=c,b$) in the BS formalism under the covariant instantaneous approximation and then give predictions of the decay widths $\Gamma(\Sigma_b^{(*)}\to\Lambda_b+\pi)$. |
hep-ph/9505294 | Xuan-Yem Pham | Hoang Ngoc Long, Nguyen Ai Viet and Pham Xuan Yem | Puzzle in the Charmed $D_s$ meson decays into pions: Could the light
quarks be not so light? | 15 pages (included 2 figures), Latex form | Phys.Lett.B357:177-185,1995 | 10.1016/0370-2693(95)00888-R | SU-4240-606, PAR/LPTHE/95-27 | hep-ph | null | The inclusive decay rate into pions of the charmed $D_s$ meson is
surprisingly larger than estimates expected from the $W$ annihilation, adopting
commonly used values of current-algebra up and down quark masses. We then go
beyond this tree diagram and consider possible QCD effects that might cause
such a large rate. There are two; the first one is related to the spectator
decay $ c{\bar s} \rightarrow s{\bar s} + u {\bar d}$ followed by $ s {\bar s}
\rightarrow d{\bar d}~,~ u{\bar u}$ via two-gluon exchange box diagram. The
second one is a gluon emission in weak annihilation for which the usual
helicity suppression is vitiated: $D_s\rightarrow W+g$ followed by $
W\rightarrow u {\bar d},~ g\rightarrow d{\bar d},~u{\bar u}$. These two
contributions, however, turn out to be insufficient to explain data, implying
that the puzzle could be understood if the up, down quarks have higher mass
values. Furthermore, on the basis of experimental informations on the spectral
function $\rho_{3\pi}(Q^2)$ deduced from the exclusive $ D_s \rightarrow 3\pi$
mode, the QCD sum rules also point to a higher mass for light quarks.
| [
{
"created": "Fri, 12 May 1995 16:28:35 GMT",
"version": "v1"
},
{
"created": "Fri, 2 Jun 1995 15:00:08 GMT",
"version": "v2"
}
] | 2008-11-26 | [
[
"Long",
"Hoang Ngoc",
""
],
[
"Viet",
"Nguyen Ai",
""
],
[
"Yem",
"Pham Xuan",
""
]
] | The inclusive decay rate into pions of the charmed $D_s$ meson is surprisingly larger than estimates expected from the $W$ annihilation, adopting commonly used values of current-algebra up and down quark masses. We then go beyond this tree diagram and consider possible QCD effects that might cause such a large rate. There are two; the first one is related to the spectator decay $ c{\bar s} \rightarrow s{\bar s} + u {\bar d}$ followed by $ s {\bar s} \rightarrow d{\bar d}~,~ u{\bar u}$ via two-gluon exchange box diagram. The second one is a gluon emission in weak annihilation for which the usual helicity suppression is vitiated: $D_s\rightarrow W+g$ followed by $ W\rightarrow u {\bar d},~ g\rightarrow d{\bar d},~u{\bar u}$. These two contributions, however, turn out to be insufficient to explain data, implying that the puzzle could be understood if the up, down quarks have higher mass values. Furthermore, on the basis of experimental informations on the spectral function $\rho_{3\pi}(Q^2)$ deduced from the exclusive $ D_s \rightarrow 3\pi$ mode, the QCD sum rules also point to a higher mass for light quarks. |
hep-ph/0108257 | Paul Stoler | Pau Stoler | Baryon form factors at high momentum transfer and generalized parton
distributions | null | Phys.Rev. D65 (2002) 053013 | 10.1103/PhysRevD.65.053013 | null | hep-ph | null | Nucleon form factors at high momentum transfer |t| are treated in the
framework of generalized parton distributions (GPD's). The possibility of
obtaining information about parton high transverse momentum components by
application of GPD's to form factors is discussed. This is illustrated by
applying an ad-hoc 2-body parton wave function to elastic nucleon form factors
F1 and F2, the N to Delta magnetic form factor G*M, and wide angle Compton
scattering (WACS) form factor R1.
| [
{
"created": "Thu, 30 Aug 2001 18:17:12 GMT",
"version": "v1"
},
{
"created": "Fri, 31 Aug 2001 18:16:31 GMT",
"version": "v2"
},
{
"created": "Tue, 4 Sep 2001 21:29:02 GMT",
"version": "v3"
}
] | 2009-11-07 | [
[
"Stoler",
"Pau",
""
]
] | Nucleon form factors at high momentum transfer |t| are treated in the framework of generalized parton distributions (GPD's). The possibility of obtaining information about parton high transverse momentum components by application of GPD's to form factors is discussed. This is illustrated by applying an ad-hoc 2-body parton wave function to elastic nucleon form factors F1 and F2, the N to Delta magnetic form factor G*M, and wide angle Compton scattering (WACS) form factor R1. |
1404.2018 | Gordan Krnjaic | Eder Izaguirre, Gordan Krnjaic, and Brian Shuve | The Galactic Center Excess from the Bottom Up | 8 pages,5 figures, references added, typos corrected, conclusions
unchanged | Phys. Rev. D 90, 055002 (2014) | 10.1103/PhysRevD.90.055002 | null | hep-ph astro-ph.CO astro-ph.HE | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | It has recently been shown that dark-matter annihilation to bottom quarks
provides a good fit to the galactic-center gamma-ray excess identified in the
Fermi-LAT data. In the favored dark matter mass range $m\sim 30-40$ GeV,
achieving the best-fit annihilation rate $\sigma v \sim 5\times 10^{-26}$
cm$^{3}$ s$^{-1}$ with perturbative couplings requires a sub-TeV mediator
particle that interacts with both dark matter and bottom quarks. In this paper,
we consider the minimal viable scenarios in which a Standard Model singlet
mediates s-channel interactions only between dark matter and bottom quarks,
focusing on axial-vector, vector, and pseudoscalar couplings. Using simulations
that include on-shell mediator production, we show that existing sbottom
searches currently offer the strongest sensitivity over a large region of the
favored parameter space explaining the gamma-ray excess, particularly for
axial-vector interactions. The 13 TeV LHC will be even more sensitive; however,
it may not be sufficient to fully cover the favored parameter space, and the
pseudoscalar scenario will remain unconstrained by these searches. We also find
that direct-detection constraints, induced through loops of bottom quarks,
complement collider bounds to disfavor the vector-current interaction when the
mediator is heavier than twice the dark matter mass. We also present some
simple models that generate pseudoscalar-mediated annihilation predominantly to
bottom quarks.
| [
{
"created": "Tue, 8 Apr 2014 06:37:30 GMT",
"version": "v1"
},
{
"created": "Fri, 11 Apr 2014 19:48:29 GMT",
"version": "v2"
}
] | 2014-09-10 | [
[
"Izaguirre",
"Eder",
""
],
[
"Krnjaic",
"Gordan",
""
],
[
"Shuve",
"Brian",
""
]
] | It has recently been shown that dark-matter annihilation to bottom quarks provides a good fit to the galactic-center gamma-ray excess identified in the Fermi-LAT data. In the favored dark matter mass range $m\sim 30-40$ GeV, achieving the best-fit annihilation rate $\sigma v \sim 5\times 10^{-26}$ cm$^{3}$ s$^{-1}$ with perturbative couplings requires a sub-TeV mediator particle that interacts with both dark matter and bottom quarks. In this paper, we consider the minimal viable scenarios in which a Standard Model singlet mediates s-channel interactions only between dark matter and bottom quarks, focusing on axial-vector, vector, and pseudoscalar couplings. Using simulations that include on-shell mediator production, we show that existing sbottom searches currently offer the strongest sensitivity over a large region of the favored parameter space explaining the gamma-ray excess, particularly for axial-vector interactions. The 13 TeV LHC will be even more sensitive; however, it may not be sufficient to fully cover the favored parameter space, and the pseudoscalar scenario will remain unconstrained by these searches. We also find that direct-detection constraints, induced through loops of bottom quarks, complement collider bounds to disfavor the vector-current interaction when the mediator is heavier than twice the dark matter mass. We also present some simple models that generate pseudoscalar-mediated annihilation predominantly to bottom quarks. |
hep-ph/9504286 | null | S.D. Bass | The final state hadrons in polarised deep inelastic scattering | Completely revised. To appear in Physics Letters B. 9 pages, 1 figure
(appended at the end) | Phys.Lett. B367 (1996) 335-341 | 10.1016/0370-2693(95)01474-8 | Cambridge HEP 95/3; J\"ulich IKP-Th 25/1995 | hep-ph | null | General arguments suggest that the non-perturbative background field in QCD
may have a non-trivial spin structure. We discuss how this effect may be
manifest in semi-inclusive measurements of fast pions in polarised deep
inelastic scattering.
| [
{
"created": "Tue, 11 Apr 1995 17:56:37 GMT",
"version": "v1"
},
{
"created": "Wed, 22 Nov 1995 14:55:16 GMT",
"version": "v2"
}
] | 2009-10-28 | [
[
"Bass",
"S. D.",
""
]
] | General arguments suggest that the non-perturbative background field in QCD may have a non-trivial spin structure. We discuss how this effect may be manifest in semi-inclusive measurements of fast pions in polarised deep inelastic scattering. |
2401.03219 | Shidong Liu | Yuanxin Zheng, Zuxin Cai, Gang Li, Shidong Liu, Jiajun Wu, Qi Wu | Hidden charmonium decays of spin-2 partner of $X(3872)$ | 9 pages, 12 figures, accepted by PRD | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The Belle collaboration recently reported a promising candidate for the
spin-2 $D^*\bar{D}^*$ partner of the $X(3872)$, called the $X_2$ for short,
having a mass of $(4014.3 \pm 4.0 \pm 1.5)~\mathrm{MeV}$ and a width of $(4 \pm
11 \pm 6)~\mathrm{MeV} $. Assuming the $X_2$ as a pure molecule of the
$D^*\bar{D}^*$, we calculated in detail the hidden charmonium decays of the
$X_2 \to J/\psi V$ and $X_2\to\eta_cP$ via the intermediate meson loops, where
$V = \rho^0\,,\omega$ and $P= \pi^0\,,\eta\,,\eta'$. The results indicate that
the decay widths are strongly dependent on the $X_2$ mass. At present center
value of the mass $4014.3~\mathrm{MeV}$, the width for the $X_2\to
J/\psi\rho^0$ is predicted to be a few tens of keV, while it is on the order of
$10^{2\text{-}3}~\mathrm{keV}$ for the $X_2\to J/ \psi\omega$; the predicted
width for the $X_2\to \eta_c \pi^0$ is about a few keV, while the widths for
$X_2\to\eta_c\eta$ and $\eta_c\eta'$ are around a few tens and tenths of keV,
respectively. We also investigated the dependence of the ratios between these
widths on the $X_2$ mass and on the $\eta$-$\eta'$ mixing angle, which may be
good quantities for experiments. We hope that the present calculations would be
checked experimentally in the future.
| [
{
"created": "Sat, 6 Jan 2024 13:56:49 GMT",
"version": "v1"
}
] | 2024-01-09 | [
[
"Zheng",
"Yuanxin",
""
],
[
"Cai",
"Zuxin",
""
],
[
"Li",
"Gang",
""
],
[
"Liu",
"Shidong",
""
],
[
"Wu",
"Jiajun",
""
],
[
"Wu",
"Qi",
""
]
] | The Belle collaboration recently reported a promising candidate for the spin-2 $D^*\bar{D}^*$ partner of the $X(3872)$, called the $X_2$ for short, having a mass of $(4014.3 \pm 4.0 \pm 1.5)~\mathrm{MeV}$ and a width of $(4 \pm 11 \pm 6)~\mathrm{MeV} $. Assuming the $X_2$ as a pure molecule of the $D^*\bar{D}^*$, we calculated in detail the hidden charmonium decays of the $X_2 \to J/\psi V$ and $X_2\to\eta_cP$ via the intermediate meson loops, where $V = \rho^0\,,\omega$ and $P= \pi^0\,,\eta\,,\eta'$. The results indicate that the decay widths are strongly dependent on the $X_2$ mass. At present center value of the mass $4014.3~\mathrm{MeV}$, the width for the $X_2\to J/\psi\rho^0$ is predicted to be a few tens of keV, while it is on the order of $10^{2\text{-}3}~\mathrm{keV}$ for the $X_2\to J/ \psi\omega$; the predicted width for the $X_2\to \eta_c \pi^0$ is about a few keV, while the widths for $X_2\to\eta_c\eta$ and $\eta_c\eta'$ are around a few tens and tenths of keV, respectively. We also investigated the dependence of the ratios between these widths on the $X_2$ mass and on the $\eta$-$\eta'$ mixing angle, which may be good quantities for experiments. We hope that the present calculations would be checked experimentally in the future. |
0710.0513 | Oleg Pavlovsky | Oleg V. Pavlovsky | Heisenberg model of the high-energy hadron collision in terms of chiral
fields | 5 pages, 2 figures, LaTeX 2e | null | null | null | hep-ph | null | Properties of chiral Born-Infeld Theory proposed as the model for shock-wave
fireball production in the hadron-hadron collisions was studied. The role of
the shock-waves in the multi-particle production was discussed.
| [
{
"created": "Tue, 2 Oct 2007 12:41:02 GMT",
"version": "v1"
}
] | 2007-10-03 | [
[
"Pavlovsky",
"Oleg V.",
""
]
] | Properties of chiral Born-Infeld Theory proposed as the model for shock-wave fireball production in the hadron-hadron collisions was studied. The role of the shock-waves in the multi-particle production was discussed. |
hep-ph/0002162 | U. Meissner | Nadia Fettes, Ulf-G. Mei{\ss}ner | Pion-nucleon scattering in chiral perturbation theory II: Fourth order
calculation | 28 pp, LaTeX2e, uses epsf, 6 figs, better discussion of the
convergence issues, accepted for publication in Nuclear Physics A | Nucl.Phys. A676 (2000) 311 | 10.1016/S0375-9474(00)00199-8 | FZJ-IKP(TH)-2000-06 | hep-ph nucl-th | null | We analyse elastic-pion nucleon scattering to fourth order in heavy baryon
chiral perturbation theory, extending the third order study published in Nucl.
Phys. A640 (1998) 199. We use various partial wave analyses to pin down the
low-energy constants from data in the physical region. The S-wave scattering
lengths are consistent with recent determinations from pionic hydrogen and
deuterium. We find an improved description of the P-waves. We also discuss the
pion-nucleon sigma term and problems related to the prediction of the
subthreshold parameters.
| [
{
"created": "Tue, 15 Feb 2000 07:23:04 GMT",
"version": "v1"
},
{
"created": "Tue, 4 Apr 2000 15:19:28 GMT",
"version": "v2"
}
] | 2009-10-31 | [
[
"Fettes",
"Nadia",
""
],
[
"Meißner",
"Ulf-G.",
""
]
] | We analyse elastic-pion nucleon scattering to fourth order in heavy baryon chiral perturbation theory, extending the third order study published in Nucl. Phys. A640 (1998) 199. We use various partial wave analyses to pin down the low-energy constants from data in the physical region. The S-wave scattering lengths are consistent with recent determinations from pionic hydrogen and deuterium. We find an improved description of the P-waves. We also discuss the pion-nucleon sigma term and problems related to the prediction of the subthreshold parameters. |
1504.05023 | Valentin V. Khoze | Valentin V. Khoze | Diagrammatic computation of multi-Higgs processes at very high energies:
scaling F holy grail with MadGraph | 12 pages, 6 figures, v2: extended discussion, the single-Higgs
form-factor effect added in the prefactor | Phys. Rev. D 92, 014021 (2015) | 10.1103/PhysRevD.92.014021 | IPPP/15/18, DCPT/15/36 | hep-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | At very high energies scattering amplitudes in a spontaneously broken gauge
theory into multi-particle final states are known to grow factorially with the
number of particles produced. Using simple scalar field theory models with and
without the VEV, we compute total cross-sections with up to 7 particles in the
final state at the leading order in perturbation theory with MadGraph. By
exploring the known scaling properties of the multi-particle rates with the
number of particles, we determine from these the general $n$-point
cross-sections in the large-$n$ limit. In the high-multiplicity regime we are
considering, n>>1 and lambda n=fixed, the perturbation theory becomes strongly
coupled with the higher-order loop effects contributing increasing powers of
lambda n. In the approximation where only the leading loop effects are
included, we show that the corresponding perturbative cross-sections grow
exponentially and ultimately violate perturbative unitarity. This occurs at
surprisingly low energy scales ~50 TeV with multiplicities above ~130. It is
expected that a repair mechanism or an extension of the theory has to set-in
before these scales are reached, possibly involving a novel non-perturbative
dynamics in the a priori weakly coupled theory.
| [
{
"created": "Mon, 20 Apr 2015 12:03:28 GMT",
"version": "v1"
},
{
"created": "Tue, 21 Apr 2015 18:34:39 GMT",
"version": "v2"
}
] | 2015-07-22 | [
[
"Khoze",
"Valentin V.",
""
]
] | At very high energies scattering amplitudes in a spontaneously broken gauge theory into multi-particle final states are known to grow factorially with the number of particles produced. Using simple scalar field theory models with and without the VEV, we compute total cross-sections with up to 7 particles in the final state at the leading order in perturbation theory with MadGraph. By exploring the known scaling properties of the multi-particle rates with the number of particles, we determine from these the general $n$-point cross-sections in the large-$n$ limit. In the high-multiplicity regime we are considering, n>>1 and lambda n=fixed, the perturbation theory becomes strongly coupled with the higher-order loop effects contributing increasing powers of lambda n. In the approximation where only the leading loop effects are included, we show that the corresponding perturbative cross-sections grow exponentially and ultimately violate perturbative unitarity. This occurs at surprisingly low energy scales ~50 TeV with multiplicities above ~130. It is expected that a repair mechanism or an extension of the theory has to set-in before these scales are reached, possibly involving a novel non-perturbative dynamics in the a priori weakly coupled theory. |
hep-ph/9510457 | Ed Stoeffhaas | V. Barger, S. Fleming, and R.J.N. Phillips | Double gluon fragmentation to $J/\psi$ pairs at the Tevatron | Revtex, 11 pages, one postscript figure. Compressed postscript file
of text with figure available at
http://phenom.physics.wisc.edu/pub/preprints/1995/madph-95-911.ps.Z or at
ftp://phenom.physics.wisc.edu/pub/preprints/1995/madph-95-911.ps.Z | Phys.Lett.B371:111-116,1996 | 10.1016/0370-2693(95)01592-2 | madph-95-911, RAL-TR-95-062 | hep-ph | null | It has been proposed that the large cross sections for prompt $\psi$,
$\psi'$, and $\chi_c$ production at the Fermilab Tevatron $p\bar p$ collider
can be explained by a dominant color-octet term in the fragmentation function
for a gluon to split into quarkonium. We show that this mechanism makes
testable predictions for double-quarkonium $\psi\psi$, $\psi\psi'$,
$\psi\chi_c$, $\psi\Upsilon$ and $\psi\chi_b$ production, as well as for $W
\psi$ production, using color-octet matrix elements previously determined from
charmonium production data. The $\psi\psi$ signal would already be measurable
at the Tevatron, while the $\psi\chi_c$ and $W\psi$ signals would be on the
edge of present detectability.
| [
{
"created": "Tue, 31 Oct 1995 19:12:48 GMT",
"version": "v1"
}
] | 2009-09-15 | [
[
"Barger",
"V.",
""
],
[
"Fleming",
"S.",
""
],
[
"Phillips",
"R. J. N.",
""
]
] | It has been proposed that the large cross sections for prompt $\psi$, $\psi'$, and $\chi_c$ production at the Fermilab Tevatron $p\bar p$ collider can be explained by a dominant color-octet term in the fragmentation function for a gluon to split into quarkonium. We show that this mechanism makes testable predictions for double-quarkonium $\psi\psi$, $\psi\psi'$, $\psi\chi_c$, $\psi\Upsilon$ and $\psi\chi_b$ production, as well as for $W \psi$ production, using color-octet matrix elements previously determined from charmonium production data. The $\psi\psi$ signal would already be measurable at the Tevatron, while the $\psi\chi_c$ and $W\psi$ signals would be on the edge of present detectability. |
1512.05493 | Adriano Doff S. Gomes A. Doff | A. Doff | The Extreme Walking Behavior in a 331-TC Model | 13 pages, 2 figures, submited to EPJC | null | 10.1140/epjc/s10052-015-3857-z | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | It is quite possible that the Technicolor problems are related to the poorly
known self-energy expression, or the way chiral symmetry breaking (CSB) is
realized in non-abelian gauge theories. Actually, the only known laboratory to
test the CSB mechanism is QCD. The TC dynamics may be quite different from the
QCD , this fact has led to the walking TC proposal making the new strong
interaction almost conformal and changing appreciably its dynamical behavior.
There are different ways to obtain of extreme walking (or quasi-conformal)
technicolor theories, in this paper we propose an scheme to obtain this
behavior based on an extension of the electroweak sector of the standard model,
in the context of so called 331-TC model.
| [
{
"created": "Thu, 17 Dec 2015 08:31:17 GMT",
"version": "v1"
}
] | 2016-02-17 | [
[
"Doff",
"A.",
""
]
] | It is quite possible that the Technicolor problems are related to the poorly known self-energy expression, or the way chiral symmetry breaking (CSB) is realized in non-abelian gauge theories. Actually, the only known laboratory to test the CSB mechanism is QCD. The TC dynamics may be quite different from the QCD , this fact has led to the walking TC proposal making the new strong interaction almost conformal and changing appreciably its dynamical behavior. There are different ways to obtain of extreme walking (or quasi-conformal) technicolor theories, in this paper we propose an scheme to obtain this behavior based on an extension of the electroweak sector of the standard model, in the context of so called 331-TC model. |
1801.02840 | Jenny List | Keisuke Fujii, Christophe Grojean, Michael E. Peskin (conveners), Tim
Barklow, Yuanning Gao, Shinya Kanemura, Hyungdo Kim, Jenny List, Mihoko
Nojiri, Maxim Perelstein, Roman P\"oschl, J\"urgen Reuter, Frank Simon,
Tomohiko Tanabe, James D. Wells, Jaehoon Yu (members), Mikael Berggren,
Moritz Habermehl, Robert Karl, Gudrid Moortgat-Pick, Sabine Riemann, Junping
Tian, Graham W. Wilson (guests), James Brau and Hitoshi Murayama (ex officio)
(The Linear Collider Collaboration Physics WG) | The role of positron polarization for the inital $250$ GeV stage of the
International Linear Collider | 19 | null | null | DESY 17-237, KEK Preprint 2017-57, SLAC-PUB-17197 | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The International Linear Collider is now proposed with a staged machine
design, with the first stage at $\sqrt{s}=$~250 GeV and an integrated
luminosity goal of 2~ab$^{-1}$. One of the questions for the machine design is
the importance of positron polarization. In this report, we review the impact
of positron polarization on the physics goals of the $250$ GeV stage of the ILC
and demonstrate that positron polarization has distinct advantages.
| [
{
"created": "Tue, 9 Jan 2018 08:51:22 GMT",
"version": "v1"
}
] | 2018-01-10 | [
[
"Fujii",
"Keisuke",
"",
"conveners"
],
[
"Grojean",
"Christophe",
"",
"conveners"
],
[
"Peskin",
"Michael E.",
"",
"conveners"
],
[
"Barklow",
"Tim",
"",
"members"
],
[
"Gao",
"Yuanning",
"",
"members"
],
[
"Kanemura",
"Shinya",
"",
"members"
],
[
"Kim",
"Hyungdo",
"",
"members"
],
[
"List",
"Jenny",
"",
"members"
],
[
"Nojiri",
"Mihoko",
"",
"members"
],
[
"Perelstein",
"Maxim",
"",
"members"
],
[
"Pöschl",
"Roman",
"",
"members"
],
[
"Reuter",
"Jürgen",
"",
"members"
],
[
"Simon",
"Frank",
"",
"members"
],
[
"Tanabe",
"Tomohiko",
"",
"members"
],
[
"Wells",
"James D.",
"",
"members"
],
[
"Yu",
"Jaehoon",
"",
"members"
],
[
"Berggren",
"Mikael",
"",
"guests"
],
[
"Habermehl",
"Moritz",
"",
"guests"
],
[
"Karl",
"Robert",
"",
"guests"
],
[
"Moortgat-Pick",
"Gudrid",
"",
"guests"
],
[
"Riemann",
"Sabine",
"",
"guests"
],
[
"Tian",
"Junping",
"",
"guests"
],
[
"Wilson",
"Graham W.",
"",
"guests"
],
[
"Brau",
"James",
"",
"ex officio"
],
[
"Murayama",
"Hitoshi",
"",
"ex officio"
]
] | The International Linear Collider is now proposed with a staged machine design, with the first stage at $\sqrt{s}=$~250 GeV and an integrated luminosity goal of 2~ab$^{-1}$. One of the questions for the machine design is the importance of positron polarization. In this report, we review the impact of positron polarization on the physics goals of the $250$ GeV stage of the ILC and demonstrate that positron polarization has distinct advantages. |
hep-ph/0312157 | Oleg Lebedev | S. Abel (IPPP), O. Lebedev (DESY), J. Santiago (IPPP) | Flavour in Intersecting Brane Models and Bounds on the String Scale | 33 pages, 11 figures, matches the NPB version | Nucl.Phys. B696 (2004) 141-173 | 10.1016/j.nuclphysb.2004.06.047 | DESY 03-203 | hep-ph hep-th | null | We study flavour issues in nonsupersymmetric intersecting brane models.
Specifically, the purpose of the present paper is twofold: (i) to determine
whether realistic flavour structures can be obtained in these models, and (ii)
to establish whether the non-supersymmetric models address the gauge hierarchy
problem. To this end, we find that realistic flavour structures, although
absent at tree level, can arise even in the simplest models after effects of 4
fermion instanton--induced operators and radiative corrections have been taken
into account. On the other hand, our analysis of flavour changing neutral
currents (FCNC), electric dipole moments (EDM), supernova SN1987A and other
constraints shows that the string scale has to be rather high, 10^4 TeV. This
implies that non-supersymmetric intersecting brane models face a severe
finetuning problem. Finally, we comment on how non--trivial flavour structures
can arise in supersymmetric models.
| [
{
"created": "Thu, 11 Dec 2003 18:53:19 GMT",
"version": "v1"
},
{
"created": "Fri, 25 Jun 2004 14:59:54 GMT",
"version": "v2"
}
] | 2009-11-10 | [
[
"Abel",
"S.",
"",
"IPPP"
],
[
"Lebedev",
"O.",
"",
"DESY"
],
[
"Santiago",
"J.",
"",
"IPPP"
]
] | We study flavour issues in nonsupersymmetric intersecting brane models. Specifically, the purpose of the present paper is twofold: (i) to determine whether realistic flavour structures can be obtained in these models, and (ii) to establish whether the non-supersymmetric models address the gauge hierarchy problem. To this end, we find that realistic flavour structures, although absent at tree level, can arise even in the simplest models after effects of 4 fermion instanton--induced operators and radiative corrections have been taken into account. On the other hand, our analysis of flavour changing neutral currents (FCNC), electric dipole moments (EDM), supernova SN1987A and other constraints shows that the string scale has to be rather high, 10^4 TeV. This implies that non-supersymmetric intersecting brane models face a severe finetuning problem. Finally, we comment on how non--trivial flavour structures can arise in supersymmetric models. |
hep-ph/9305343 | Lisa Randall | Lisa Randall and Eric Sather | The Rate for $B\bbar$ Production Accompanied by a Single Pion | 7 pages, uses harvmac, MIT-CTP-2214 | null | null | null | hep-ph | null | We study the rate for the production of ${B B^\pm \pi^\mp}$, where the sign
of the charged pion tags the flavor content of the neutral $B$ meson. We
estimate this branching ratio, employing the heavy meson chiral effective
theory. We find that at center of mass energy of approximately 12 GeV, a $B$
meson pair should be produced as often with and without an accompanying charged
pion. We also calculate two pion production at this center of mass energy, and
find that it is negligible, as is the rate for rho production. We consider the
implications for CP violation studies. (Invited Talk, 1993 Electroweak
Rencontres de Moriond)
| [
{
"created": "Fri, 28 May 1993 02:12:07 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Randall",
"Lisa",
""
],
[
"Sather",
"Eric",
""
]
] | We study the rate for the production of ${B B^\pm \pi^\mp}$, where the sign of the charged pion tags the flavor content of the neutral $B$ meson. We estimate this branching ratio, employing the heavy meson chiral effective theory. We find that at center of mass energy of approximately 12 GeV, a $B$ meson pair should be produced as often with and without an accompanying charged pion. We also calculate two pion production at this center of mass energy, and find that it is negligible, as is the rate for rho production. We consider the implications for CP violation studies. (Invited Talk, 1993 Electroweak Rencontres de Moriond) |
2112.04429 | Bachir Moussallam | B. Moussallam | Deriving experimental constraints on the scalar form factor in the
second-class $\tau \to\eta \pi \nu$ mode | Contribution to the 16th International Workshop on Tau Lepton Physics
(TAU2021). Submission to SciPost | null | null | null | hep-ph | http://creativecommons.org/licenses/by/4.0/ | The rare second-class decay mode of the $\tau$ into $\eta\pi\nu$ could be
observed for the first time at Belle II. It is important to try to derive a
reliable evaluation of the branching fraction and of the energy distribution of
this mode within the standard-model. Many predictions exist already in the
literature which can differ by one to two orders of magnitude. Here, an
approach based on a systematic use of the property of analyticity of form
factors and scattering amplitudes in QCD is discussed. In particular, we will
show that the scalar form factor in the $\tau$ decay can be related to
photon-photon scattering and radiative $\phi$ decay amplitudes for which
precise experimental measurements have been performed by the Belle and KLOE
collaborations.
| [
{
"created": "Wed, 8 Dec 2021 17:39:52 GMT",
"version": "v1"
}
] | 2021-12-09 | [
[
"Moussallam",
"B.",
""
]
] | The rare second-class decay mode of the $\tau$ into $\eta\pi\nu$ could be observed for the first time at Belle II. It is important to try to derive a reliable evaluation of the branching fraction and of the energy distribution of this mode within the standard-model. Many predictions exist already in the literature which can differ by one to two orders of magnitude. Here, an approach based on a systematic use of the property of analyticity of form factors and scattering amplitudes in QCD is discussed. In particular, we will show that the scalar form factor in the $\tau$ decay can be related to photon-photon scattering and radiative $\phi$ decay amplitudes for which precise experimental measurements have been performed by the Belle and KLOE collaborations. |
1102.2548 | Daniel Feldman | Daniel Feldman, Katherine Freese, Pran Nath, Brent D. Nelson, Gregory
Peim | Predictive Signatures of Supersymmetry: Measuring the Dark Matter Mass
and Gluino Mass with Early LHC data | null | Phys.Rev.D84:015007,2011 | 10.1103/PhysRevD.84.015007 | null | hep-ph astro-ph.HE | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present a focused study of a predictive unified model whose measurable
consequences are immediately relevant to early discovery prospects of
supersymmetry at the LHC. ATLAS and CMS have released their analysis with
35~pb$^{-1}$ of data and the model class we discuss is consistent with this
data. It is shown that with an increase in luminosity the LSP dark matter mass
and the gluino mass can be inferred from simple observables such as kinematic
edges in leptonic channels and peak values in effective mass distributions.
Specifically, we consider cases in which the neutralino is of low mass and
where the relic density consistent with WMAP observations arises via the
exchange of Higgs bosons in unified supergravity models. The magnitudes of the
gaugino masses are sharply limited to focused regions of the parameter space,
and in particular the dark matter mass lies in the range $\sim (50-65) ~\rm
GeV$ with an upper bound on the gluino mass of $575~{\rm GeV}$, with a typical
mass of $450~{\rm GeV}$. We find that all model points in this paradigm are
discoverable at the LHC at $\sqrt s = 7 \rm ~TeV$. We determine lower bounds on
the entire sparticle spectrum in this model based on existing experimental
constraints. In addition, we find the spin-independent cross section for
neutralino scattering on nucleons to be generally in the range of $\sigma^{\rm
SI}_{\na p} = 10^{-46 \pm 1}~\rm cm^2$ with much higher cross sections also
possible. Thus direct detection experiments such as CDMS and XENON already
constrain some of the allowed parameter space of the low mass gaugino models
and further data will provide important cross-checks of the model assumptions
in the near future.
| [
{
"created": "Sun, 13 Feb 2011 01:19:51 GMT",
"version": "v1"
}
] | 2011-07-28 | [
[
"Feldman",
"Daniel",
""
],
[
"Freese",
"Katherine",
""
],
[
"Nath",
"Pran",
""
],
[
"Nelson",
"Brent D.",
""
],
[
"Peim",
"Gregory",
""
]
] | We present a focused study of a predictive unified model whose measurable consequences are immediately relevant to early discovery prospects of supersymmetry at the LHC. ATLAS and CMS have released their analysis with 35~pb$^{-1}$ of data and the model class we discuss is consistent with this data. It is shown that with an increase in luminosity the LSP dark matter mass and the gluino mass can be inferred from simple observables such as kinematic edges in leptonic channels and peak values in effective mass distributions. Specifically, we consider cases in which the neutralino is of low mass and where the relic density consistent with WMAP observations arises via the exchange of Higgs bosons in unified supergravity models. The magnitudes of the gaugino masses are sharply limited to focused regions of the parameter space, and in particular the dark matter mass lies in the range $\sim (50-65) ~\rm GeV$ with an upper bound on the gluino mass of $575~{\rm GeV}$, with a typical mass of $450~{\rm GeV}$. We find that all model points in this paradigm are discoverable at the LHC at $\sqrt s = 7 \rm ~TeV$. We determine lower bounds on the entire sparticle spectrum in this model based on existing experimental constraints. In addition, we find the spin-independent cross section for neutralino scattering on nucleons to be generally in the range of $\sigma^{\rm SI}_{\na p} = 10^{-46 \pm 1}~\rm cm^2$ with much higher cross sections also possible. Thus direct detection experiments such as CDMS and XENON already constrain some of the allowed parameter space of the low mass gaugino models and further data will provide important cross-checks of the model assumptions in the near future. |
hep-ph/9707370 | Barbara MELE , Roma1 | E.Gabrielli, V.A. Ilyin, B.Mele | Measuring Z-gamma-Higgs vertex effects at e-gamma linear colliders | 11 pages, 8 figures. A gzipped complete postscript file is available
at ftp://hpteo.roma1.infn.it/pub/preprints/mele/Rome1-1178.ps.gz To appear in
the Report DESY 97-123E | null | null | ROME1-1178/97 | hep-ph | null | The one-loop process e,gamma->e,h for intermediate Higgs masses is
considered. Exact cross sections for unpolarized and longitudinally polarized
beams are computed and found to be more than two orders of magnitude larger
than the rates for the crossed process e,e->gamma,h, in the energy range
\sqrt{s}=(0.5-2) TeV. We show that, apart from being competitive with the
gamma,gamma->H process for testing the one-loop gamma-gamma-H vertex, by
requiring a final electron tagged at large angle the channel e,gamma->e,h
provides an excellent way of testing the Z-gamma-H vertex.
| [
{
"created": "Thu, 17 Jul 1997 11:12:27 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Gabrielli",
"E.",
""
],
[
"Ilyin",
"V. A.",
""
],
[
"Mele",
"B.",
""
]
] | The one-loop process e,gamma->e,h for intermediate Higgs masses is considered. Exact cross sections for unpolarized and longitudinally polarized beams are computed and found to be more than two orders of magnitude larger than the rates for the crossed process e,e->gamma,h, in the energy range \sqrt{s}=(0.5-2) TeV. We show that, apart from being competitive with the gamma,gamma->H process for testing the one-loop gamma-gamma-H vertex, by requiring a final electron tagged at large angle the channel e,gamma->e,h provides an excellent way of testing the Z-gamma-H vertex. |
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