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1706.08767
Juri Fiaschi
Juri Fiaschi, Elena Accomando, Francesco Hautmann, Stefano Moretti, Claire H. Shepherd-Themistocleous
Photon-induced contributions to di-lepton production at the LHC Run II
Proceedings of XXV International Workshop on Deep-Inelastic Scattering and Related Subjects, 3-7 April 2017, University of Birmingham, UK
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We report on recent studies of photon-induced (PI) contributions to di-lepton production and their implications for Beyond Standard Model (BSM) $Z^\prime$-bosons searches at the LHC.
[ { "created": "Tue, 27 Jun 2017 10:40:47 GMT", "version": "v1" } ]
2017-06-28
[ [ "Fiaschi", "Juri", "" ], [ "Accomando", "Elena", "" ], [ "Hautmann", "Francesco", "" ], [ "Moretti", "Stefano", "" ], [ "Shepherd-Themistocleous", "Claire H.", "" ] ]
We report on recent studies of photon-induced (PI) contributions to di-lepton production and their implications for Beyond Standard Model (BSM) $Z^\prime$-bosons searches at the LHC.
0907.0352
Bernard Pire
L. Szymanowski
From Diphoton GDAs and Photon GPDs to the chiral odd Photon DA
6pages, 2 figures, to be published in the proceedings of the international conference onthe structure and the Interactions of the photon, DESY, Hamburg, May 2009
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The photon is a very interesting object for QCD studies since it has both a pointlike coupling to quarks, which yields a perturbative part of photon's wave function, and a non-perturbative coupling related to the magnetic susceptibility of the QCD vacuum and which builds its chiral-odd twist-2 distribution amplitude. The first feature allows us to compute the photon anomalous generalized parton distributions (GPD) and the diphoton generalized distribution amplitudes. The second feature allows us to use a transverse spin asymmetry to probe the chiral odd distribution amplitude of the photon.
[ { "created": "Thu, 2 Jul 2009 11:56:34 GMT", "version": "v1" } ]
2009-07-03
[ [ "Szymanowski", "L.", "" ] ]
The photon is a very interesting object for QCD studies since it has both a pointlike coupling to quarks, which yields a perturbative part of photon's wave function, and a non-perturbative coupling related to the magnetic susceptibility of the QCD vacuum and which builds its chiral-odd twist-2 distribution amplitude. The first feature allows us to compute the photon anomalous generalized parton distributions (GPD) and the diphoton generalized distribution amplitudes. The second feature allows us to use a transverse spin asymmetry to probe the chiral odd distribution amplitude of the photon.
2312.13373
Susanne Westhoff
Susanne Westhoff
FIMP Dark Matter at the LHC
7 pages, 4 figures
null
null
null
hep-ph hep-ex
http://creativecommons.org/licenses/by-nc-nd/4.0/
This brief summary targets feebly interacting massive particles, FIMPs, which are interesting candidates for dark matter. The cosmic history of FIMP dark matter often leads to predictions of long-lived mediator particles at laboratory experiments. I point out the role of the LHC in searching for such particles and sketch its complementarity with low-energy experiments.
[ { "created": "Wed, 20 Dec 2023 19:03:03 GMT", "version": "v1" } ]
2023-12-22
[ [ "Westhoff", "Susanne", "" ] ]
This brief summary targets feebly interacting massive particles, FIMPs, which are interesting candidates for dark matter. The cosmic history of FIMP dark matter often leads to predictions of long-lived mediator particles at laboratory experiments. I point out the role of the LHC in searching for such particles and sketch its complementarity with low-energy experiments.
1302.4281
Jacques Soffer
Claude Bourrely, Franco Buccella, Jacques Soffer
The transverse momentum dependent statistical parton distributions revisited
18 pages, 5 figures, to appear in Int. Journal Modern Physics A
null
10.1142/S0217751X13500267
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The extension of the statistical parton distributions to include their transverse momentum dependence (TMD) is revisited by considering that the proton target has a finite longitudinal momentum. The TMD will be generated by means of a transverse energy sum rule. The new results are mainly relevant for electron-proton inelastic collisions in the low $Q^2$ region. We take into account the effects of the Melosh-Wigner rotation for the helicity distributions.
[ { "created": "Mon, 18 Feb 2013 14:18:29 GMT", "version": "v1" } ]
2015-06-15
[ [ "Bourrely", "Claude", "" ], [ "Buccella", "Franco", "" ], [ "Soffer", "Jacques", "" ] ]
The extension of the statistical parton distributions to include their transverse momentum dependence (TMD) is revisited by considering that the proton target has a finite longitudinal momentum. The TMD will be generated by means of a transverse energy sum rule. The new results are mainly relevant for electron-proton inelastic collisions in the low $Q^2$ region. We take into account the effects of the Melosh-Wigner rotation for the helicity distributions.
0808.1825
Arif Akhundov A.
Arif Akhundov
Electroweak Physics with ATLAS
3 pages (LaTeX), 4 eps figures, Poster at the 34th International Conference on High Energy Physics (ICHEP08), Philadelphia, USA, July 2008
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The precision measurements of electroweak parameters of the Standard Model with the ATLAS detector at LHC are reviewed. An emphasis is put on the bridge connecting the ATLAS measurements with the SM analysis at LEP/SLC and the Tevatron.
[ { "created": "Wed, 13 Aug 2008 13:08:15 GMT", "version": "v1" } ]
2008-08-14
[ [ "Akhundov", "Arif", "" ] ]
The precision measurements of electroweak parameters of the Standard Model with the ATLAS detector at LHC are reviewed. An emphasis is put on the bridge connecting the ATLAS measurements with the SM analysis at LEP/SLC and the Tevatron.
1204.5746
Vicent Mateu
Riccardo Abbate, Michael Fickinger, Andre H. Hoang, Vicent Mateu, Iain W. Stewart
Precision Thrust Cumulant Moments at N^3LL
23 pages, 16 figures. v2: minor changes, references added, some data added. v3: minor modifications to match published version
null
10.1103/PhysRevD.86.094002
MIT--CTP 4343; IFIC/12-02; UWThPh-2012-9; LPN12-023; INT-PUB-12-006
hep-ph hep-ex nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider cumulant moments (cumulants) of the thrust distribution using predictions of the full spectrum for thrust including O(alpha_s^3) fixed order results, resummation of singular N^3LL logarithmic contributions, and a class of leading power corrections in a renormalon-free scheme. From a global fit to the first thrust moment we extract the strong coupling and the leading power correction matrix element Omega_1. We obtain alpha_s(m_Z) = 0.1141 \pm (0.0004)_exp \pm (0.0014)_hadr \pm (0.0007)_pert, where the 1-sigma uncertainties are experimental, from hadronization (related to Omega_1) and perturbative, respectively, and Omega_1 = 0.372 \pm (0.044)_exp \pm (0.039)_pert GeV. The n-th thrust cumulants for n > 1 are completely insensitive to Omega_1, and therefore a good instrument for extracting information on higher order power corrections, Omega'_n/Q^n, from moment data. We find (\tilde Omega'_2)^(1/2) = 0.74 \pm (0.11)_exp \pm (0.09)_pert GeV.
[ { "created": "Wed, 25 Apr 2012 20:00:01 GMT", "version": "v1" }, { "created": "Sat, 26 May 2012 12:57:24 GMT", "version": "v2" }, { "created": "Wed, 28 Nov 2012 01:34:16 GMT", "version": "v3" } ]
2013-05-30
[ [ "Abbate", "Riccardo", "" ], [ "Fickinger", "Michael", "" ], [ "Hoang", "Andre H.", "" ], [ "Mateu", "Vicent", "" ], [ "Stewart", "Iain W.", "" ] ]
We consider cumulant moments (cumulants) of the thrust distribution using predictions of the full spectrum for thrust including O(alpha_s^3) fixed order results, resummation of singular N^3LL logarithmic contributions, and a class of leading power corrections in a renormalon-free scheme. From a global fit to the first thrust moment we extract the strong coupling and the leading power correction matrix element Omega_1. We obtain alpha_s(m_Z) = 0.1141 \pm (0.0004)_exp \pm (0.0014)_hadr \pm (0.0007)_pert, where the 1-sigma uncertainties are experimental, from hadronization (related to Omega_1) and perturbative, respectively, and Omega_1 = 0.372 \pm (0.044)_exp \pm (0.039)_pert GeV. The n-th thrust cumulants for n > 1 are completely insensitive to Omega_1, and therefore a good instrument for extracting information on higher order power corrections, Omega'_n/Q^n, from moment data. We find (\tilde Omega'_2)^(1/2) = 0.74 \pm (0.11)_exp \pm (0.09)_pert GeV.
hep-ph/0008307
Daniel Winder
T.S. Evans, H.F. Jones and D. Winder
Non-perturbative calculations of a global U(1) theory at finite density and temperature
24 pages, 11 figures
Nucl.Phys. B598 (2001) 578-600
10.1016/S0550-3213(00)00753-7
null
hep-ph
null
We use an optimised hopping parameter expansion for the free energy (linear delta expansion) to study the phase transitions at finite temperature and finite charge density in a global U(1) scalar Higgs sector on the lattice at large lattice couplings. We are able to plot out phase diagrams in lattice parameter space and find that the standard second-order phase transition with temperature at zero chemical potential becomes first order as the chemical potential increases.
[ { "created": "Tue, 29 Aug 2000 16:54:55 GMT", "version": "v1" } ]
2009-10-31
[ [ "Evans", "T. S.", "" ], [ "Jones", "H. F.", "" ], [ "Winder", "D.", "" ] ]
We use an optimised hopping parameter expansion for the free energy (linear delta expansion) to study the phase transitions at finite temperature and finite charge density in a global U(1) scalar Higgs sector on the lattice at large lattice couplings. We are able to plot out phase diagrams in lattice parameter space and find that the standard second-order phase transition with temperature at zero chemical potential becomes first order as the chemical potential increases.
2205.01895
Yi-Dong Song
Yi-Dong Song, Shou-Shan Bao
Study of the $tH$ production at 14TeV and 100TeV $pp$ colliders
7 pages, 25 figures
null
null
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
The flavor-changing neutral current interactions in the standard model are suppressed seriously and such interactions can be used to search the new physics beyond SM. The top quark and Higgs bosons are heavier than the other particles in SM, we can expect the new physics plays a more important role in their interactions. In this work, we study the flavor-changing neutral current interactions between the top quark $\bar{t}q H$ through the production of the single top associated with a Higgs boson on 14TeV and 100TeV $pp$ colliders. We consider the leptonic decay channels of Higgs and study the signal. We find a sensitive region $0.4\leq\Delta R\leq1.4$ for the leptons from Higgs bosons and $\Delta R\geq1.8$ between the jets from top quark and leptons. We investigate the detective abilities of the hadron colliders for the processes. Although this process seems not comparable with $pp\to t\bar{t}$ with $t\to H q$ decay, it is still attractive since this process can be used to distinguish the $y_{tu}$ and $y_{tc}$.
[ { "created": "Wed, 4 May 2022 05:16:07 GMT", "version": "v1" } ]
2022-05-05
[ [ "Song", "Yi-Dong", "" ], [ "Bao", "Shou-Shan", "" ] ]
The flavor-changing neutral current interactions in the standard model are suppressed seriously and such interactions can be used to search the new physics beyond SM. The top quark and Higgs bosons are heavier than the other particles in SM, we can expect the new physics plays a more important role in their interactions. In this work, we study the flavor-changing neutral current interactions between the top quark $\bar{t}q H$ through the production of the single top associated with a Higgs boson on 14TeV and 100TeV $pp$ colliders. We consider the leptonic decay channels of Higgs and study the signal. We find a sensitive region $0.4\leq\Delta R\leq1.4$ for the leptons from Higgs bosons and $\Delta R\geq1.8$ between the jets from top quark and leptons. We investigate the detective abilities of the hadron colliders for the processes. Although this process seems not comparable with $pp\to t\bar{t}$ with $t\to H q$ decay, it is still attractive since this process can be used to distinguish the $y_{tu}$ and $y_{tc}$.
0812.1053
Christian Weiss
M. Strikman, C. Weiss
Rapidity gap survival in central exclusive diffraction: Dynamical mechanisms and uncertainties
6 pages, 3 figures. Proceedings of "HERA and the LHC" CERN-DESY Workshop, 2007-2008
null
null
JLAB-THY-08-919
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We summarize our understanding of the dynamical mechanisms governing rapidity gap survival in central exclusive diffraction, pp -> p + H + p (H = high-mass system), and discuss the uncertainties in present estimates of the survival probability. The main suppression of diffractive scattering is due to inelastic soft spectator interactions at small pp impact parameters and can be described in a mean-field approximation (independent hard and soft interactions). Moderate extra suppression results from fluctuations of the partonic configurations of the colliding protons. At LHC energies absorptive interactions of hard spectator partons associated with the gg -> H process reach the black-disk regime and cause substantial additional suppression, pushing the survival probability below 0.01.
[ { "created": "Fri, 5 Dec 2008 00:12:01 GMT", "version": "v1" } ]
2008-12-08
[ [ "Strikman", "M.", "" ], [ "Weiss", "C.", "" ] ]
We summarize our understanding of the dynamical mechanisms governing rapidity gap survival in central exclusive diffraction, pp -> p + H + p (H = high-mass system), and discuss the uncertainties in present estimates of the survival probability. The main suppression of diffractive scattering is due to inelastic soft spectator interactions at small pp impact parameters and can be described in a mean-field approximation (independent hard and soft interactions). Moderate extra suppression results from fluctuations of the partonic configurations of the colliding protons. At LHC energies absorptive interactions of hard spectator partons associated with the gg -> H process reach the black-disk regime and cause substantial additional suppression, pushing the survival probability below 0.01.
1707.06570
Ji Xu
Wei Wang, Zhi-Peng Xing, Ji Xu
Weak Decays of Doubly Heavy Baryons: SU(3) Analysis
28 pages, 12 figures, 22 tables
Eur. Phys. J. C (2017) 77: 800
10.1140/epjc/s10052-017-5363-y
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Motivated by the recent LHCb observation of doubly-charmed baryon $\Xi_{cc}^{++}$ in the $\Lambda_c^+ K^-\pi^+\pi^+$ final state, we analyze the weak decays of doubly heavy baryons $\Xi_{cc}$, $\Omega_{cc}$, $\Xi_{bc}$, $\Omega_{bc}$, $\Xi_{bb}$ and $\Omega_{bb}$ under the flavor SU(3) symmetry. Decay amplitudes for various semileptonic and nonleptonic decays are parametrized in terms of a few SU(3) irreducible amplitudes. We find a number of relations or sum rules between decay widths and CP asymmetries, which can be examined in future measurements at experimental facilities like LHC, Belle II and CEPC. Moreover once a few decay branching fractions are measured in future, some of these relations may provide hints for exploration of new decay modes.
[ { "created": "Thu, 20 Jul 2017 15:26:37 GMT", "version": "v1" }, { "created": "Sat, 4 Nov 2017 10:40:20 GMT", "version": "v2" } ]
2017-11-28
[ [ "Wang", "Wei", "" ], [ "Xing", "Zhi-Peng", "" ], [ "Xu", "Ji", "" ] ]
Motivated by the recent LHCb observation of doubly-charmed baryon $\Xi_{cc}^{++}$ in the $\Lambda_c^+ K^-\pi^+\pi^+$ final state, we analyze the weak decays of doubly heavy baryons $\Xi_{cc}$, $\Omega_{cc}$, $\Xi_{bc}$, $\Omega_{bc}$, $\Xi_{bb}$ and $\Omega_{bb}$ under the flavor SU(3) symmetry. Decay amplitudes for various semileptonic and nonleptonic decays are parametrized in terms of a few SU(3) irreducible amplitudes. We find a number of relations or sum rules between decay widths and CP asymmetries, which can be examined in future measurements at experimental facilities like LHC, Belle II and CEPC. Moreover once a few decay branching fractions are measured in future, some of these relations may provide hints for exploration of new decay modes.
1112.5457
Ian Shoemaker
Ian M. Shoemaker and Luca Vecchi
Unitarity and Monojet Bounds on Models for DAMA, CoGeNT, and CRESST-II
7 pages, 5 figures; updated references, typo in Eq. 2 corrected (v2); clarified discussion of the interpretation of the unitarity constraint; one new figure; conclusions unchanged
null
10.1103/PhysRevD.86.015023
LA-UR-11-12298
hep-ph astro-ph.CO hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
If dark matter interacts with quarks or gluons, the mediator of these interactions is either directly accessible at the LHC or is so heavy that its effects are encoded in contact operators. We find that the self-consistency of a contact operator description at the LHC implies bounds on the mediator scale stronger than those found from missing energy searches. This translates into spin-independent elastic scattering cross-sections at a level < 10^-41 cm^2, with direct implications for the DAMA, CoGeNT, and CRESST-II anomalies. We then carefully explore the potential of monojet searches in the light mediator limit, focusing on a Z' model with arbitrary couplings to quarks and dark matter. We find that the Tevatron data currently provides the most stringent bounds for dark matter and Z' masses below 100 GeV, and that these searches can constrain models for the DAMA, CoGeNT, and CRESST-II anomalies only if the mediator can decay to a pair of dark matter particles.
[ { "created": "Thu, 22 Dec 2011 21:00:02 GMT", "version": "v1" }, { "created": "Wed, 4 Jan 2012 18:48:45 GMT", "version": "v2" }, { "created": "Wed, 21 Mar 2012 17:34:55 GMT", "version": "v3" } ]
2013-05-30
[ [ "Shoemaker", "Ian M.", "" ], [ "Vecchi", "Luca", "" ] ]
If dark matter interacts with quarks or gluons, the mediator of these interactions is either directly accessible at the LHC or is so heavy that its effects are encoded in contact operators. We find that the self-consistency of a contact operator description at the LHC implies bounds on the mediator scale stronger than those found from missing energy searches. This translates into spin-independent elastic scattering cross-sections at a level < 10^-41 cm^2, with direct implications for the DAMA, CoGeNT, and CRESST-II anomalies. We then carefully explore the potential of monojet searches in the light mediator limit, focusing on a Z' model with arbitrary couplings to quarks and dark matter. We find that the Tevatron data currently provides the most stringent bounds for dark matter and Z' masses below 100 GeV, and that these searches can constrain models for the DAMA, CoGeNT, and CRESST-II anomalies only if the mediator can decay to a pair of dark matter particles.
1301.3672
Markus Hopfer
Markus Hopfer, Andreas Windisch, Reinhard Alkofer
The Quark-Gluon Vertex in Landau gauge QCD
8 pages, Confinement X proceedings
PoS Confinement X (2013) 073
null
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The coupled system of the quark-gluon vertex and quark propagator Dyson-Schwinger equations (DSEs) is investigated within Landau gauge QCD. The aim is to get a deeper insight into the mechanisms of quark confinement and dynamical chiral symmetry breaking and into a possible relation between these two phenomena. To this end an earlier study is extended by improving systematically on the truncations imposed on the quark-gluon vertex DSE. A clear infrared enhancement for all tensor structures of the quark-gluon vertex is obtained.
[ { "created": "Wed, 16 Jan 2013 12:29:13 GMT", "version": "v1" } ]
2013-01-17
[ [ "Hopfer", "Markus", "" ], [ "Windisch", "Andreas", "" ], [ "Alkofer", "Reinhard", "" ] ]
The coupled system of the quark-gluon vertex and quark propagator Dyson-Schwinger equations (DSEs) is investigated within Landau gauge QCD. The aim is to get a deeper insight into the mechanisms of quark confinement and dynamical chiral symmetry breaking and into a possible relation between these two phenomena. To this end an earlier study is extended by improving systematically on the truncations imposed on the quark-gluon vertex DSE. A clear infrared enhancement for all tensor structures of the quark-gluon vertex is obtained.
hep-ph/0511201
Paul F. Harrison
James D. Bjorken, P.F. Harrison and W.G. Scott
Simplified Unitarity Triangles for the Lepton Sector
4 pages, including one figure. v2: corrected typos in Eqs. 1 and 11; added new references to prior, relevant work; re-ordered some references; made 3 minor wording changes
Phys.Rev.D74:073012,2006
10.1103/PhysRevD.74.073012
null
hep-ph
null
Encouraged by the latest SNO results, we consider the lepton mixing matrix in the approximation that the nu_2 mass eigenstate is trimaximally (democratically) mixed. This suggests a new parameterization of the remaining mixing degrees of freedom, which eschews mixing angles, dealing instead, directly with the complex parameter U_e3 of the mixing matrix. Unitarity triangles then take a particularly simple form, which we hope will faciltate comparison with experiment.
[ { "created": "Wed, 16 Nov 2005 18:06:37 GMT", "version": "v1" }, { "created": "Thu, 14 Sep 2006 01:30:05 GMT", "version": "v2" } ]
2011-09-29
[ [ "Bjorken", "James D.", "" ], [ "Harrison", "P. F.", "" ], [ "Scott", "W. G.", "" ] ]
Encouraged by the latest SNO results, we consider the lepton mixing matrix in the approximation that the nu_2 mass eigenstate is trimaximally (democratically) mixed. This suggests a new parameterization of the remaining mixing degrees of freedom, which eschews mixing angles, dealing instead, directly with the complex parameter U_e3 of the mixing matrix. Unitarity triangles then take a particularly simple form, which we hope will faciltate comparison with experiment.
1602.03714
Rune Mikkelsen Mr
R.E. Mikkelsen, T. Poulsen, U.I. Uggerh{\o}j, S.R. Klein
Characteristics of Cherenkov Radiation in Naturally Occuring Ice
null
Phys. Rev. D 93, 053006 (2016)
10.1103/PhysRevD.93.053006
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We revisit the theory of Cherenkov radiation in uniaxial crystals. Historically, a number of flawed attempts have been made at explaining this radiation phenomenon and a consistent error-free description is nowhere available. We apply our calculation to a large modern day telescope - IceCube. Being located at the Antarctica, this detector makes use of the naturally occuring ice as a medium to generate Cherenkov radiation. However, due to the high pressure at the depth of the detector site, large volumes of hexagonal ice crystals are formed. We calculate how this affects the Cherenkov radiation yield and angular dependence. We conclude that the effect is small, at most about a percent, and would only be relevant in future high precision instruments like e.g. Precision IceCube Next Generation Upgrade (PINGU). For radio-Cherenkov experiments which use the presence of a clear Cherenkov cone to determine the arrival direction, any variation in emission angle will directly and linearly translate into a change in apparent neutrino direction. In closing, we also describe a simple experiment to test this formalism, and calculate the impact of anisotropy on light-yields from lead tungstate crystals as used, for example, in the CMS calorimeter at the CERN LHC.
[ { "created": "Thu, 11 Feb 2016 13:03:23 GMT", "version": "v1" } ]
2016-03-23
[ [ "Mikkelsen", "R. E.", "" ], [ "Poulsen", "T.", "" ], [ "Uggerhøj", "U. I.", "" ], [ "Klein", "S. R.", "" ] ]
We revisit the theory of Cherenkov radiation in uniaxial crystals. Historically, a number of flawed attempts have been made at explaining this radiation phenomenon and a consistent error-free description is nowhere available. We apply our calculation to a large modern day telescope - IceCube. Being located at the Antarctica, this detector makes use of the naturally occuring ice as a medium to generate Cherenkov radiation. However, due to the high pressure at the depth of the detector site, large volumes of hexagonal ice crystals are formed. We calculate how this affects the Cherenkov radiation yield and angular dependence. We conclude that the effect is small, at most about a percent, and would only be relevant in future high precision instruments like e.g. Precision IceCube Next Generation Upgrade (PINGU). For radio-Cherenkov experiments which use the presence of a clear Cherenkov cone to determine the arrival direction, any variation in emission angle will directly and linearly translate into a change in apparent neutrino direction. In closing, we also describe a simple experiment to test this formalism, and calculate the impact of anisotropy on light-yields from lead tungstate crystals as used, for example, in the CMS calorimeter at the CERN LHC.
0711.1001
Y.H. Ahn
Y.H.Ahn (Yonsei U.), Sin Kyu Kang (Seoul Natl. U. of Technology), C.S.Kim, Jake Lee (Yonsei U.)
Leptogenesis in a seesaw model with Fritzsch type lepton mass matrices
null
Phys.Rev.D77:073009,2008
10.1103/PhysRevD.77.073009
null
hep-ph
null
We investigate how the baryon asymmetry of our universe via leptogenesis can be achieved within the framework of the seesaw model with Fritzsch type lepton mass matrices proposed by Fukugita $et. al$. We study the cases with CP-violating phases in charged lepton Yukawa matrix, however, with and without Dirac neutrino Yukawa phases. We consider both flavor independent and flavor dependent leptogenesis, and demonstrate how they lead to different amounts of lepton asymmetries in detail. In particular, it is shown that flavor dependent leptogenesis in this model can be worked out only when the CP phases in Dirac neutrino Yukawa matrix become zero at the GUT scale. In addition to the CP phases, for successful leptogenesis in the model it is required that the degeneracy of the heavy Majorana neutrino mass spectrum should be broken and we also show that the breakdown of the degeneracy can be radiatively induced.
[ { "created": "Wed, 7 Nov 2007 03:13:30 GMT", "version": "v1" } ]
2008-11-26
[ [ "Ahn", "Y. H.", "", "Yonsei U." ], [ "Kang", "Sin Kyu", "", "Seoul Natl. U. of Technology" ], [ "Kim", "C. S.", "", "Yonsei U." ], [ "Lee", "Jake", "", "Yonsei U." ] ]
We investigate how the baryon asymmetry of our universe via leptogenesis can be achieved within the framework of the seesaw model with Fritzsch type lepton mass matrices proposed by Fukugita $et. al$. We study the cases with CP-violating phases in charged lepton Yukawa matrix, however, with and without Dirac neutrino Yukawa phases. We consider both flavor independent and flavor dependent leptogenesis, and demonstrate how they lead to different amounts of lepton asymmetries in detail. In particular, it is shown that flavor dependent leptogenesis in this model can be worked out only when the CP phases in Dirac neutrino Yukawa matrix become zero at the GUT scale. In addition to the CP phases, for successful leptogenesis in the model it is required that the degeneracy of the heavy Majorana neutrino mass spectrum should be broken and we also show that the breakdown of the degeneracy can be radiatively induced.
hep-ph/9709325
Valery Lyubovitskij
M. A. Ivanov (JINR, Dubna), J. G. Korner (Mainz U., Inst. Phys.), V. E. Lyubovitskij (JINR, Dubna and Tomsk U.), A. G. Rusetsky (JINR, Dubna and Tbilisi U.)
Exclusive nonleptonic bottom to charm baryon decays including nonfactorizable contributions
14 pages, LaTeX-file
Mod.Phys.Lett. A13 (1998) 181-192
10.1142/S0217732398000231
Preprint Mainz Univ. MZ-TH/97-21
hep-ph
null
Exclusive nonleptonic decays of bottom baryons to charm baryons and pseudoscalar light mesons are analyzed within a relativistic three-quark model. We include factorizing as well as nonfactorizing contributions to the decay amplitudes. The total contribution of the nonfactorizing diagrams amount up to 30% of the factorizing contributions in amplitude. We present detailed predictions for rates and asymmetry parameters.
[ { "created": "Fri, 12 Sep 1997 09:25:02 GMT", "version": "v1" }, { "created": "Sat, 31 Jan 1998 15:24:02 GMT", "version": "v2" } ]
2009-10-30
[ [ "Ivanov", "M. A.", "", "JINR, Dubna" ], [ "Korner", "J. G.", "", "Mainz U., Inst. Phys." ], [ "Lyubovitskij", "V. E.", "", "JINR, Dubna and Tomsk U." ], [ "Rusetsky", "A. G.", "", "JINR, Dubna and\n Tbilisi U." ] ]
Exclusive nonleptonic decays of bottom baryons to charm baryons and pseudoscalar light mesons are analyzed within a relativistic three-quark model. We include factorizing as well as nonfactorizing contributions to the decay amplitudes. The total contribution of the nonfactorizing diagrams amount up to 30% of the factorizing contributions in amplitude. We present detailed predictions for rates and asymmetry parameters.
1308.6364
Xing-Gang Wu
Sheng-Quan Wang, Xing-Gang Wu, Xu-Chang Zheng, Jian-Ming Shen and Qiong-Lian Zhang
The Higgs boson inclusive decay channels $H \to b\bar{b}$ and $H \to gg$ up to four-loop level
14 pages, 7 figures. References updated and discussions improved. To be published in Eur.Phys.J.C
Eur. Phys. J. C 74 (2014) 2825
10.1140/epjc/s10052-014-2825-3
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The principle of maximum conformality (PMC) has been suggested to eliminate the renormalization scheme and renormalization scale uncertainties, which are unavoidable for the conventional scale setting and are usually important errors for theoretical estimations. In this paper, by applying PMC scale setting, we analyze two important inclusive Standard Model Higgs decay channels, $H\rightarrow b\bar{b}$ and $H\rightarrow gg$, up to four-loop and three-loop levels accordingly. After PMC scale setting, it is found that the conventional scale uncertainty for these two channels can be eliminated to a high degree. There is small residual initial scale dependence for the Higgs decay widths due to unknown higher-order $\{\beta_i\}$-terms. Up to four-loop level, we obtain $\Gamma(H\rightarrow b\bar{b}) = 2.389\pm0.073 \pm0.041$ MeV and up to three-loop level, we obtain $\Gamma(H\rightarrow gg) = 0.373\pm0.030$ MeV, where the first error is caused by varying $M_H=126\pm4$ GeV and the second error for $H\to b\bar{b}$ is caused by varying the $\overline{\rm MS}$-running mass $m_b(m_b)=4.18\pm0.03$ GeV. Taking $H\to b\bar{b}$ as an example, we present a comparison of three BLM-based scale setting approaches, e.g. the PMC-I approach based on the PMC-BLM correspondence, the $R_\delta$-scheme and the seBLM approach, all of which are designed to provide effective ways to identify non-conformal $\{\beta_i\}$-series at each perturbative order. At four-loop level, all those approaches lead to good pQCD convergence, they have almost the same pQCD series, and their predictions are almost independent on the initial renormalization scale. In this sense, those approaches are equivalent to each other.
[ { "created": "Thu, 29 Aug 2013 04:39:21 GMT", "version": "v1" }, { "created": "Wed, 11 Dec 2013 00:33:54 GMT", "version": "v2" }, { "created": "Sat, 15 Mar 2014 00:51:42 GMT", "version": "v3" } ]
2014-04-14
[ [ "Wang", "Sheng-Quan", "" ], [ "Wu", "Xing-Gang", "" ], [ "Zheng", "Xu-Chang", "" ], [ "Shen", "Jian-Ming", "" ], [ "Zhang", "Qiong-Lian", "" ] ]
The principle of maximum conformality (PMC) has been suggested to eliminate the renormalization scheme and renormalization scale uncertainties, which are unavoidable for the conventional scale setting and are usually important errors for theoretical estimations. In this paper, by applying PMC scale setting, we analyze two important inclusive Standard Model Higgs decay channels, $H\rightarrow b\bar{b}$ and $H\rightarrow gg$, up to four-loop and three-loop levels accordingly. After PMC scale setting, it is found that the conventional scale uncertainty for these two channels can be eliminated to a high degree. There is small residual initial scale dependence for the Higgs decay widths due to unknown higher-order $\{\beta_i\}$-terms. Up to four-loop level, we obtain $\Gamma(H\rightarrow b\bar{b}) = 2.389\pm0.073 \pm0.041$ MeV and up to three-loop level, we obtain $\Gamma(H\rightarrow gg) = 0.373\pm0.030$ MeV, where the first error is caused by varying $M_H=126\pm4$ GeV and the second error for $H\to b\bar{b}$ is caused by varying the $\overline{\rm MS}$-running mass $m_b(m_b)=4.18\pm0.03$ GeV. Taking $H\to b\bar{b}$ as an example, we present a comparison of three BLM-based scale setting approaches, e.g. the PMC-I approach based on the PMC-BLM correspondence, the $R_\delta$-scheme and the seBLM approach, all of which are designed to provide effective ways to identify non-conformal $\{\beta_i\}$-series at each perturbative order. At four-loop level, all those approaches lead to good pQCD convergence, they have almost the same pQCD series, and their predictions are almost independent on the initial renormalization scale. In this sense, those approaches are equivalent to each other.
1108.0331
Valery Lyubovitskij
K.B. Vijaya Kumar, Amand Faessler, Thomas Gutsche, Barry R. Holstein, Valery E. Lyubovitskij
Hyperon forward spin polarizabilty gamma0
10 pages
Phys.Rev.D84:076007,2011
10.1103/PhysRevD.84.076007
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present the results of a systematic leading order calculation of hyperon Compton scattering and extract the forward spin polarizability gamma0 of hyperons within the framework of SU(3) heavy baryon chiral perturbation theory (HBChPT). The results obtained for gamma0 in the case of nucleons agree with that of the known results of SU(2) HBChPT when kaon loops are not considered.
[ { "created": "Mon, 1 Aug 2011 15:03:01 GMT", "version": "v1" }, { "created": "Mon, 26 Sep 2011 07:49:53 GMT", "version": "v2" }, { "created": "Wed, 19 Oct 2011 10:54:58 GMT", "version": "v3" } ]
2011-10-20
[ [ "Kumar", "K. B. Vijaya", "" ], [ "Faessler", "Amand", "" ], [ "Gutsche", "Thomas", "" ], [ "Holstein", "Barry R.", "" ], [ "Lyubovitskij", "Valery E.", "" ] ]
We present the results of a systematic leading order calculation of hyperon Compton scattering and extract the forward spin polarizability gamma0 of hyperons within the framework of SU(3) heavy baryon chiral perturbation theory (HBChPT). The results obtained for gamma0 in the case of nucleons agree with that of the known results of SU(2) HBChPT when kaon loops are not considered.
1210.7407
Prasanta Das Kumar
Prasanta Kumar Das, J. R. Selvaganapathy, Chandradew Sharma, Tarun Kumar Jha and V. Sunil Kumar
Impact of a light stabilized radion in supernovae cooling
18 pages, 8 eps figures. arXiv admin note: substantial text overlap with arXiv:0801.1269; and with arXiv:hep-ph/0201099 by other authors
null
null
null
hep-ph astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In the Randall-Sundrum model where the Standard Model fields are confined to the TeV brane located at the orbifold point $\theta = \pi$ and the gravity peaks at the Planck brane located at $\theta = 0$, the stabilized modulus (radion) field is required to stabilize the size of the fifth spatial dimension. It can be produced copiously inside the supernova core due to nucleon-nucleon bremstrahlung, electron-positron and plasmon-plasmon annihilations, which then subsequently decays to neutrino-antineutrino pair and take away the energy released in SN1987A explosion. Assuming that the supernovae cooling rate $\dot{\varepsilon} \le 7.288\times 10^{-27} \rm{GeV}$, we find the lower bound on the radion vev $\vphi \sim 9.0$ TeV, 2.2 TeV and 0.9 TeV corresponding to the radion mass $m_\phi = 5$ GeV, 20 GeV and 50 GeV, respectively.
[ { "created": "Sun, 28 Oct 2012 06:30:36 GMT", "version": "v1" } ]
2012-10-30
[ [ "Das", "Prasanta Kumar", "" ], [ "Selvaganapathy", "J. R.", "" ], [ "Sharma", "Chandradew", "" ], [ "Jha", "Tarun Kumar", "" ], [ "Kumar", "V. Sunil", "" ] ]
In the Randall-Sundrum model where the Standard Model fields are confined to the TeV brane located at the orbifold point $\theta = \pi$ and the gravity peaks at the Planck brane located at $\theta = 0$, the stabilized modulus (radion) field is required to stabilize the size of the fifth spatial dimension. It can be produced copiously inside the supernova core due to nucleon-nucleon bremstrahlung, electron-positron and plasmon-plasmon annihilations, which then subsequently decays to neutrino-antineutrino pair and take away the energy released in SN1987A explosion. Assuming that the supernovae cooling rate $\dot{\varepsilon} \le 7.288\times 10^{-27} \rm{GeV}$, we find the lower bound on the radion vev $\vphi \sim 9.0$ TeV, 2.2 TeV and 0.9 TeV corresponding to the radion mass $m_\phi = 5$ GeV, 20 GeV and 50 GeV, respectively.
1407.4415
Shmuel Nussinov
Amit Loewy, Shmuel Nussinov, Sheldon L. Glashow
The Effect of Doppler Broadening on the $6.3 \ PeV$ $W^-$ Resonance in $\bar{\nu}_e e^-$ Collisions
null
null
null
null
hep-ph astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We calculate the Doppler broadening of the $W^-$ resonance produced in $\bar{\nu}_e e^-$ collisions of cosmic anti-neutrinos with $E_{\nu}\approx 6.3 \ PeV$ with electrons in atoms up to Iron. Revisiting this issue is prompted by recent observations of PeV neutrinos by Ice-Cube. Despite its poor energy resolution, the $20\%$ Doppler broadening of the resonance due to electronic motions can produce observable effects via non-linear neutrino absorption near the resonance. The attendant suppression of the peak cross section allows $\bar{\nu}_e$ to travel correspondingly longer distances. While this effect is unlikely to be directly detected in the near future, it may facilitate terrestrial tomography at depths of $\sim 10 \ km$, complementing deeper explorations using the more frequent nuclear interactions at lower energies.
[ { "created": "Wed, 16 Jul 2014 18:26:14 GMT", "version": "v1" } ]
2014-07-17
[ [ "Loewy", "Amit", "" ], [ "Nussinov", "Shmuel", "" ], [ "Glashow", "Sheldon L.", "" ] ]
We calculate the Doppler broadening of the $W^-$ resonance produced in $\bar{\nu}_e e^-$ collisions of cosmic anti-neutrinos with $E_{\nu}\approx 6.3 \ PeV$ with electrons in atoms up to Iron. Revisiting this issue is prompted by recent observations of PeV neutrinos by Ice-Cube. Despite its poor energy resolution, the $20\%$ Doppler broadening of the resonance due to electronic motions can produce observable effects via non-linear neutrino absorption near the resonance. The attendant suppression of the peak cross section allows $\bar{\nu}_e$ to travel correspondingly longer distances. While this effect is unlikely to be directly detected in the near future, it may facilitate terrestrial tomography at depths of $\sim 10 \ km$, complementing deeper explorations using the more frequent nuclear interactions at lower energies.
hep-ph/0512335
Chun-Khiang Chua
Hai-Yang Cheng, Chun-Khiang Chua and Shang-Yuu Tsai
Doubly Charmful Baryonic B Decays
14 pages, 5 figures, to appear in Phys. Rev. D
Phys.Rev.D73:074015,2006
10.1103/PhysRevD.73.074015
null
hep-ph hep-ex
null
There are two apparent puzzles connected with the two-body and three-body doubly charmed baryonic B decays. First, earlier calculations based on QCD sum rules or the diquark model predict $Br(\bar B^0\to\Xi_c^+\bar\Lambda_c^-)\approx Br(\bar B^0\to\B_c\bar N)$, while experimentally the former has a rate two orders of magnitude larger than the latter. Second, a naive estimate of the branching ratio $10^{-9}$ for the color-suppressed three-body decay $\bar B\to\Lambda_c^+\bar\Lambda_c^-K$, which is highly suppressed by phase space, is too small by five to six orders of magnitude compared to experiment. We show that the great suppression for the $\Lambda_c^+\bar\Lambda_c^-K$ production can be alleviated provided that there exists a narrow hidden charm bound state with a mass near the $\Lambda_c\bar\Lambda_c$ threshold. This new state that couples strongly to the charmed baryon pair can be searched for in B decays and in $p\bar p$ collisions by studying the mass spectrum of $D^{(*)}\bar D^{(*)}$ or $\Lambda_c\bar\Lambda_c$. The doubly charmful decay $\bar B\to\Xi_c\bar\Lambda_c$ has a configuration more favorable than the singly charmful one such as $\bar B^0\to\Lambda_c\bar p$ since no hard gluon is needed to produce the energetic $\Xi_c\bar\Lambda_c$ pair in the former decay, while two hard gluons are needed for the latter process. Assuming that a soft $q\bar q$ quark pair is produced through the $\sigma$ and $\pi$ meson exchanges in the configuration for $\bar B\to \Xi_c\bar\Lambda_c$, it is found that its branching ratio is of order $10^{-3}$, in agreement with experiment.
[ { "created": "Tue, 27 Dec 2005 07:04:00 GMT", "version": "v1" }, { "created": "Fri, 7 Apr 2006 12:19:18 GMT", "version": "v2" } ]
2008-11-26
[ [ "Cheng", "Hai-Yang", "" ], [ "Chua", "Chun-Khiang", "" ], [ "Tsai", "Shang-Yuu", "" ] ]
There are two apparent puzzles connected with the two-body and three-body doubly charmed baryonic B decays. First, earlier calculations based on QCD sum rules or the diquark model predict $Br(\bar B^0\to\Xi_c^+\bar\Lambda_c^-)\approx Br(\bar B^0\to\B_c\bar N)$, while experimentally the former has a rate two orders of magnitude larger than the latter. Second, a naive estimate of the branching ratio $10^{-9}$ for the color-suppressed three-body decay $\bar B\to\Lambda_c^+\bar\Lambda_c^-K$, which is highly suppressed by phase space, is too small by five to six orders of magnitude compared to experiment. We show that the great suppression for the $\Lambda_c^+\bar\Lambda_c^-K$ production can be alleviated provided that there exists a narrow hidden charm bound state with a mass near the $\Lambda_c\bar\Lambda_c$ threshold. This new state that couples strongly to the charmed baryon pair can be searched for in B decays and in $p\bar p$ collisions by studying the mass spectrum of $D^{(*)}\bar D^{(*)}$ or $\Lambda_c\bar\Lambda_c$. The doubly charmful decay $\bar B\to\Xi_c\bar\Lambda_c$ has a configuration more favorable than the singly charmful one such as $\bar B^0\to\Lambda_c\bar p$ since no hard gluon is needed to produce the energetic $\Xi_c\bar\Lambda_c$ pair in the former decay, while two hard gluons are needed for the latter process. Assuming that a soft $q\bar q$ quark pair is produced through the $\sigma$ and $\pi$ meson exchanges in the configuration for $\bar B\to \Xi_c\bar\Lambda_c$, it is found that its branching ratio is of order $10^{-3}$, in agreement with experiment.
2210.01826
Giacomo Cacciapaglia
G. Cacciapaglia, T. Flacke, M. Kunkel, W. Porod, L. Schwarze
Exploring extended Higgs sectors via pair production at the LHC
30 pages, 14 figures
null
10.1007/JHEP12(2022)087
KIAS-A22008
hep-ph hep-ex
http://creativecommons.org/licenses/by/4.0/
Higgs sectors extended by electroweakly charged scalars can be explored by scalar pair production at the LHC. We consider a fermiophobic scenario, with decays into a pair of gauge bosons, and a fermiophilic one, with decays into top and bottom quarks. After establishing the current bounds on simplified models, we focus on an SU(5)/SO(5) composite Higgs model. This first exploration demonstrates the need for dedicated searches at current and future colliders.
[ { "created": "Tue, 4 Oct 2022 18:00:49 GMT", "version": "v1" } ]
2023-01-04
[ [ "Cacciapaglia", "G.", "" ], [ "Flacke", "T.", "" ], [ "Kunkel", "M.", "" ], [ "Porod", "W.", "" ], [ "Schwarze", "L.", "" ] ]
Higgs sectors extended by electroweakly charged scalars can be explored by scalar pair production at the LHC. We consider a fermiophobic scenario, with decays into a pair of gauge bosons, and a fermiophilic one, with decays into top and bottom quarks. After establishing the current bounds on simplified models, we focus on an SU(5)/SO(5) composite Higgs model. This first exploration demonstrates the need for dedicated searches at current and future colliders.
1611.01460
James Currie
James Currie, E.W.N. Glover, Joao Pires
NNLO QCD predictions for single jet inclusive production at the LHC
5 pages, 3 figures (version accepted for publication in PRL)
Phys. Rev. Lett. 118, 072002 (2017)
10.1103/PhysRevLett.118.072002
IPPP/16/110, MPP-2016-322
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We report the first calculation of fully differential jet production in all partonic channels at next-to-next-to leading order (NNLO) in perturbative QCD and compare to the available ATLAS 7 TeV data. We discuss the size and shape of the perturbative corrections along with their associated scale variation across a wide range in jet transverse momentum, $p_{T}$, and rapidity, $y$. We find significant effects, especially at low $p_{T}$, and discuss the possible implications for Parton Distribution Function fits.
[ { "created": "Fri, 4 Nov 2016 17:31:03 GMT", "version": "v1" }, { "created": "Thu, 13 Apr 2017 16:25:38 GMT", "version": "v2" } ]
2017-04-14
[ [ "Currie", "James", "" ], [ "Glover", "E. W. N.", "" ], [ "Pires", "Joao", "" ] ]
We report the first calculation of fully differential jet production in all partonic channels at next-to-next-to leading order (NNLO) in perturbative QCD and compare to the available ATLAS 7 TeV data. We discuss the size and shape of the perturbative corrections along with their associated scale variation across a wide range in jet transverse momentum, $p_{T}$, and rapidity, $y$. We find significant effects, especially at low $p_{T}$, and discuss the possible implications for Parton Distribution Function fits.
hep-ph/0003205
Daijiro Suematsu
Y. Daikoku and D. Suematsu
Mass bound of the lightest neutral Higgs scalar in the extra U(1) models
22 pages, latex, 11 eps-figures
Phys.Rev.D62:095006,2000
10.1103/PhysRevD.62.095006
KANAZAWA-99-15
hep-ph
null
The upper mass bound of the lightest neutral Higgs scalar is studied in the $\mu$ problem solvable extra U(1) models by using the analysis of the renormalization group equations. In order to restrict the parameter space we take account of a condition of the radiative symmetry breaking and some phenomenological constraints. We compare the bound obtained based on this restricted parameter space with the one of the next to the minimal supersymmetric standard model (NMSSM). Features of the scalar potential and renormalization group equations of the Yukawa couplings among Higgs chiral supermultiplets are rather different between them. They can reflect in this bound.
[ { "created": "Tue, 21 Mar 2000 13:12:27 GMT", "version": "v1" } ]
2009-11-19
[ [ "Daikoku", "Y.", "" ], [ "Suematsu", "D.", "" ] ]
The upper mass bound of the lightest neutral Higgs scalar is studied in the $\mu$ problem solvable extra U(1) models by using the analysis of the renormalization group equations. In order to restrict the parameter space we take account of a condition of the radiative symmetry breaking and some phenomenological constraints. We compare the bound obtained based on this restricted parameter space with the one of the next to the minimal supersymmetric standard model (NMSSM). Features of the scalar potential and renormalization group equations of the Yukawa couplings among Higgs chiral supermultiplets are rather different between them. They can reflect in this bound.
1706.01063
Cliff Burgess
C.P. Burgess, Peter Hayman, Markus Rummel and Laszlo Zalavari
Point-Particle Effective Field Theory III: Relativistic Fermions and the Dirac Equation
29 pages plus appendices, 3 figures
null
10.1007/JHEP09(2017)007
null
hep-ph hep-th nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We formulate point-particle effective field theory (PPEFT) for relativistic spin-half fermions interacting with a massive, charged finite-sized source using a first-quantized effective field theory for the heavy compact object and a second-quantized language for the lighter fermion with which it interacts. This description shows how to determine the near-source boundary condition for the Dirac field in terms of the relevant physical properties of the source, and reduces to the standard choices in the limit of a point source. Using a first-quantized effective description is appropriate when the compact object is sufficiently heavy, and is simpler than (though equivalent to) the effective theory that treats the compact source in a second-quantized way. As an application we use the PPEFT to parameterize the leading energy shift for the bound energy levels due to finite-sized source effects in a model-independent way, allowing these effects to be fit in precision measurements. Besides capturing finite-source-size effects, the PPEFT treatment also efficiently captures how other short-distance source interactions can shift bound-state energy levels, such as due to vacuum polarization (through the Uehling potential) or strong interactions for Coulomb bound states of hadrons, or any hypothetical new short-range forces sourced by nuclei.
[ { "created": "Sun, 4 Jun 2017 12:19:57 GMT", "version": "v1" } ]
2017-09-20
[ [ "Burgess", "C. P.", "" ], [ "Hayman", "Peter", "" ], [ "Rummel", "Markus", "" ], [ "Zalavari", "Laszlo", "" ] ]
We formulate point-particle effective field theory (PPEFT) for relativistic spin-half fermions interacting with a massive, charged finite-sized source using a first-quantized effective field theory for the heavy compact object and a second-quantized language for the lighter fermion with which it interacts. This description shows how to determine the near-source boundary condition for the Dirac field in terms of the relevant physical properties of the source, and reduces to the standard choices in the limit of a point source. Using a first-quantized effective description is appropriate when the compact object is sufficiently heavy, and is simpler than (though equivalent to) the effective theory that treats the compact source in a second-quantized way. As an application we use the PPEFT to parameterize the leading energy shift for the bound energy levels due to finite-sized source effects in a model-independent way, allowing these effects to be fit in precision measurements. Besides capturing finite-source-size effects, the PPEFT treatment also efficiently captures how other short-distance source interactions can shift bound-state energy levels, such as due to vacuum polarization (through the Uehling potential) or strong interactions for Coulomb bound states of hadrons, or any hypothetical new short-range forces sourced by nuclei.
hep-ph/9910354
Ferenc Csikor
F. Csikor
Electroweak phase transition: recent results
Latex, 3 pages, 4 figures. Talk presented at the International Europhysics Conference on High Energy Physics (EPS-HEP99), Tampere, Finland, Jul y 15-21, 1999
null
null
ITP-Budapest 553
hep-ph
null
Recent results of four-dimensional (4d) lattice simulations on the finite temperature electroweak phase transition (EWPT) are discussed. The phase transition is of first order in the SU(2)-Higgs model below the end point Higgs mass 66.5$\pm$1.4 GeV. For larger masses a rapid cross-over appears. This result completely agrees with the results of the dimensional reduction approach. Including the full Standard Model (SM) perturbatively the end point is at 72.1$\pm$1.4 GeV. Combined with recent LEP Higgs mass lower bounds, this excludes any EWPT in the SM. A one-loop calculation of the static potential makes possible a precise comparison of the lattice and perturbative results. Recent 4d lattice studies of the Minimal Supersymmetric SM (MSSM) are also mentioned.
[ { "created": "Fri, 15 Oct 1999 07:04:09 GMT", "version": "v1" } ]
2007-05-23
[ [ "Csikor", "F.", "" ] ]
Recent results of four-dimensional (4d) lattice simulations on the finite temperature electroweak phase transition (EWPT) are discussed. The phase transition is of first order in the SU(2)-Higgs model below the end point Higgs mass 66.5$\pm$1.4 GeV. For larger masses a rapid cross-over appears. This result completely agrees with the results of the dimensional reduction approach. Including the full Standard Model (SM) perturbatively the end point is at 72.1$\pm$1.4 GeV. Combined with recent LEP Higgs mass lower bounds, this excludes any EWPT in the SM. A one-loop calculation of the static potential makes possible a precise comparison of the lattice and perturbative results. Recent 4d lattice studies of the Minimal Supersymmetric SM (MSSM) are also mentioned.
hep-ph/9711277
Gregory Korchemsky
G.P.Korchemsky
Conformal bootstrap for the BFKL Pomeron
23 pages, LaTeX style, 2 figures embedded with epsf.sty
Nucl.Phys. B550 (1999) 397-423
10.1016/S0550-3213(99)00185-6
LPTHE-Orsay-97-62
hep-ph hep-th
null
We calculate the interaction vertex of three BFKL states including the bare triple BFKL Pomeron coupling and discuss its relation with the correlation functions in two-dimensional conformal field theory. We construct the operator algebra of the fields interpolating the BFKL states and show that in the multi-color limit the vertex satisfies the constraints imposed by the conformal bootstrap on the structure constants of the operator product expansion in conformal field theory.
[ { "created": "Mon, 10 Nov 1997 13:34:02 GMT", "version": "v1" }, { "created": "Fri, 14 Nov 1997 16:36:19 GMT", "version": "v2" } ]
2009-10-30
[ [ "Korchemsky", "G. P.", "" ] ]
We calculate the interaction vertex of three BFKL states including the bare triple BFKL Pomeron coupling and discuss its relation with the correlation functions in two-dimensional conformal field theory. We construct the operator algebra of the fields interpolating the BFKL states and show that in the multi-color limit the vertex satisfies the constraints imposed by the conformal bootstrap on the structure constants of the operator product expansion in conformal field theory.
1409.3278
Leonardo Cirto
Leonardo J. L. Cirto, Constantino Tsallis, Cheuk-Yin Wong and Grzegorz Wilk
The transverse-momenta distributions in high-energy $pp$ collisions -- A statistical-mechanical approach
4 pages, 1 figure
null
null
null
hep-ph cond-mat.stat-mech
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We analyze LHC available data measuring the distribution probability of transverse momenta~$p_T$ in proton-proton collisions at $\sqrt{s}=0.9\,\textrm{TeV}$ (CMS, ALICE, ATLAS) and $\sqrt{s}=7\,\textrm{TeV}$ (CMS, ATLAS). A remarkably good fitting can be obtained, along fourteen decades in magnitude, by phenomenologically using $q$-statistics for a {\it single} particle of a two-dimensional relativistic ideal gas. The parameters that have been obtained by assuming $\textrm{d}N/p_T\textrm{d}p_T\textrm{d}y \propto e_q^{-E_T/T}$ at mid-rapidity are, in all cases, $q \simeq 1.1$ and $T\simeq 0.13\,\textrm{GeV}$ (which satisfactorily compares with the pion mass). This fact suggests the approximate validity of a "no-hair" statistical-mechanical description of the hard-scattering hadron-production process in which the detailed mechanisms of parton scattering, parton cascades, parton fragmentation, running coupling and other information can be subsumed under the stochastic dynamics in the lowest-order description. In addition to that basic structure, a finer analysis of the data suggests a small oscillatory structure on top of the leading $q$-exponential. The physical origin of such intriguing oscillatory behavior remains elusive, though it could be related to some sort of fractality or scale-invariance within the system.
[ { "created": "Wed, 10 Sep 2014 23:52:00 GMT", "version": "v1" } ]
2014-09-12
[ [ "Cirto", "Leonardo J. L.", "" ], [ "Tsallis", "Constantino", "" ], [ "Wong", "Cheuk-Yin", "" ], [ "Wilk", "Grzegorz", "" ] ]
We analyze LHC available data measuring the distribution probability of transverse momenta~$p_T$ in proton-proton collisions at $\sqrt{s}=0.9\,\textrm{TeV}$ (CMS, ALICE, ATLAS) and $\sqrt{s}=7\,\textrm{TeV}$ (CMS, ATLAS). A remarkably good fitting can be obtained, along fourteen decades in magnitude, by phenomenologically using $q$-statistics for a {\it single} particle of a two-dimensional relativistic ideal gas. The parameters that have been obtained by assuming $\textrm{d}N/p_T\textrm{d}p_T\textrm{d}y \propto e_q^{-E_T/T}$ at mid-rapidity are, in all cases, $q \simeq 1.1$ and $T\simeq 0.13\,\textrm{GeV}$ (which satisfactorily compares with the pion mass). This fact suggests the approximate validity of a "no-hair" statistical-mechanical description of the hard-scattering hadron-production process in which the detailed mechanisms of parton scattering, parton cascades, parton fragmentation, running coupling and other information can be subsumed under the stochastic dynamics in the lowest-order description. In addition to that basic structure, a finer analysis of the data suggests a small oscillatory structure on top of the leading $q$-exponential. The physical origin of such intriguing oscillatory behavior remains elusive, though it could be related to some sort of fractality or scale-invariance within the system.
1404.1339
Sergei Demidov
S.V. Demidov, D.S. Gorbunov
SUSY in the sky or a keV signature of sub-GeV gravitino dark matter
8 pages, published version
null
10.1103/PhysRevD.90.035014
INR-TH-2014-010
hep-ph astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We point out that recently discovered 3.5 keV line in X-ray spectra from various galaxy clusters and the Andromeda galaxy can be naturally explained by physics of a sector responsible for spontaneous supersymmetry breaking in models with R-parity. In this scenario the source of this line could be decay of sgoldstino - scalar superpartner of massive gravitino. At the same time the dominant dark matter component is stable gravitino whose mass is predicted to be about 0.25 GeV.
[ { "created": "Fri, 4 Apr 2014 18:57:49 GMT", "version": "v1" }, { "created": "Mon, 8 Sep 2014 09:47:28 GMT", "version": "v2" } ]
2015-06-19
[ [ "Demidov", "S. V.", "" ], [ "Gorbunov", "D. S.", "" ] ]
We point out that recently discovered 3.5 keV line in X-ray spectra from various galaxy clusters and the Andromeda galaxy can be naturally explained by physics of a sector responsible for spontaneous supersymmetry breaking in models with R-parity. In this scenario the source of this line could be decay of sgoldstino - scalar superpartner of massive gravitino. At the same time the dominant dark matter component is stable gravitino whose mass is predicted to be about 0.25 GeV.
hep-ph/0610376
Thomas Dent
Thomas Dent
Varying "constants" in astrophysics and cosmology and ...
Space limited to 4 pages, AIP 6x9 inch format. To appear in Proceedings of SUSY06, the 14th International Conference on Supersymmetry and the Unification of Fundamental Interactions, UC Irvine, California, 12-17 June 2006
AIPConf.Proc.903:665-668,2007
10.1063/1.2735271
null
hep-ph astro-ph gr-qc
null
We review astrophysical, cosmological and terrestrial evidence for and against the constancy of fundamental parameters of particle physics, and discuss theoretical issues of unification and scalar-mediated forces, finding that the current rate of variation is bounded by limits on violations of the weak equivalence principle.
[ { "created": "Fri, 27 Oct 2006 20:34:44 GMT", "version": "v1" } ]
2008-11-26
[ [ "Dent", "Thomas", "" ] ]
We review astrophysical, cosmological and terrestrial evidence for and against the constancy of fundamental parameters of particle physics, and discuss theoretical issues of unification and scalar-mediated forces, finding that the current rate of variation is bounded by limits on violations of the weak equivalence principle.
1006.5014
Jos\'e Francisco Zurita
Marcela Carena, Eduardo Pont\'on, Jos\'e Zurita
SUSY Higgs bosons and beyond
Contribution to the XVIII International Workshop on Deep-Inelastic Scattering and Related Subjects, April 19 -23, 2010, Florence, Italy. 5 pages, 2 figures
PoS DIS2010:212,2010
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider extensions of the Minimal Supersymmetric Standard Model (MSSM) where the extra degrees of freedom interact weakly with the Higgs sector. These models allow to relax the tension between the lower bound on the lightest CP even Higgs mass from direct LEP searches and the theoretical upper bound of the MSSM. We study the beyond MSSM (BMSSM) effects via an effective field-theory approach, assuming that the MSSM is valid up to a heavy physics scale M. We compute the masses, couplings and branching fractions of the Higgs sector, including all the relevant corrections up to order 1/M^2. We find that the collider phenomenology can be greatly different with respect to both the SM and the MSSM.
[ { "created": "Fri, 25 Jun 2010 16:04:35 GMT", "version": "v1" } ]
2010-11-19
[ [ "Carena", "Marcela", "" ], [ "Pontón", "Eduardo", "" ], [ "Zurita", "José", "" ] ]
We consider extensions of the Minimal Supersymmetric Standard Model (MSSM) where the extra degrees of freedom interact weakly with the Higgs sector. These models allow to relax the tension between the lower bound on the lightest CP even Higgs mass from direct LEP searches and the theoretical upper bound of the MSSM. We study the beyond MSSM (BMSSM) effects via an effective field-theory approach, assuming that the MSSM is valid up to a heavy physics scale M. We compute the masses, couplings and branching fractions of the Higgs sector, including all the relevant corrections up to order 1/M^2. We find that the collider phenomenology can be greatly different with respect to both the SM and the MSSM.
hep-ph/9906334
Stefano Moretti
V.A. Khoze, D.J. Miller, S. Moretti and W.J. Stirling
Hadronic returns to the Z in electron-positron annihilation at high energy
25 pages, latex, uses epsfig, 10 figures
JHEP 9907:014,1999
10.1088/1126-6708/1999/07/014
RAL-TR-98-036, DTP/98/14
hep-ph
null
The production of four hadronic jets in e+e- collisions above the Z pole is dominated by the QCD e+e- --> qqqq,qqgg processes and, for sufficiently high energy, the electroweak e+e- --> W+W- --> qqqq process. However there is another mechanism for producing four jets, e+e- --> Z gg --> qqgg, which can be regarded as a `hadronic return' to the Z pole. We investigate this new process in detail
[ { "created": "Fri, 11 Jun 1999 09:14:02 GMT", "version": "v1" } ]
2009-10-31
[ [ "Khoze", "V. A.", "" ], [ "Miller", "D. J.", "" ], [ "Moretti", "S.", "" ], [ "Stirling", "W. J.", "" ] ]
The production of four hadronic jets in e+e- collisions above the Z pole is dominated by the QCD e+e- --> qqqq,qqgg processes and, for sufficiently high energy, the electroweak e+e- --> W+W- --> qqqq process. However there is another mechanism for producing four jets, e+e- --> Z gg --> qqgg, which can be regarded as a `hadronic return' to the Z pole. We investigate this new process in detail
0905.2729
Kazuhiro Tanaka
Hiroyuki Kawamura (1), Kazuhiro Tanaka (2) ((1) Univ. of Liverpool, (2) Juntendo Univ.)
OPE for B-meson distribution amplitude and dimension-5 HQET operators
7 pages, 1 figure; to appear in the proceedings of the International Workshop on Effective Field Theories: from the pion to the upsilon (EFT09), February 2-6, 2009, Valencia, Spain
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The $B$-meson light-cone distribution amplitude (LCDA) is defined as the matrix element of a quark-antiquark bilocal light-cone operator in the heavy-quark effective theory (HQET) and is a building block of QCD factorization formula for exclusive $B$-meson decays. When the corresponding bilocal HQET operator has a light-like distance $t$ between the quark and antiquark fields, the scale $\sim 1/t$ separates the UV and IR regions, which induce the cusp singularity in radiative corrections and the mixing of multiparticle states in nonperturbative corrections, respectively. We treat the bilocal HQET operator based on the operator product expansion (OPE), disentangling the singularities from the IR and UV regions systematically. The matching at the next-to-leading order $\alpha_s$ is performed in the $\overline{\rm MS}$ scheme with a complete set of local operators of dimension $d \le 5$, through a manifestly gauge-invariant calculation organizing all contributions in the coordinate space. The result exhibits the Wilson coefficients with Sudakov-type double logarithms and the higher-dimensional operators with additional gluons. This OPE yields the $B$-meson LCDA for $t$ less than $\sim 1$ GeV$^{-1}$, in terms of $\bar{\Lambda}= m_B - m_b$ and the two additional HQET parameters as matrix elements of dimension-5 operators. The impact of these novel HQET parameters on the integral relevant to exclusive $B$ decays, $\lambda_B$, is also discussed.
[ { "created": "Sun, 17 May 2009 11:45:54 GMT", "version": "v1" } ]
2009-05-19
[ [ "Kawamura", "Hiroyuki", "" ], [ "Tanaka", "Kazuhiro", "" ] ]
The $B$-meson light-cone distribution amplitude (LCDA) is defined as the matrix element of a quark-antiquark bilocal light-cone operator in the heavy-quark effective theory (HQET) and is a building block of QCD factorization formula for exclusive $B$-meson decays. When the corresponding bilocal HQET operator has a light-like distance $t$ between the quark and antiquark fields, the scale $\sim 1/t$ separates the UV and IR regions, which induce the cusp singularity in radiative corrections and the mixing of multiparticle states in nonperturbative corrections, respectively. We treat the bilocal HQET operator based on the operator product expansion (OPE), disentangling the singularities from the IR and UV regions systematically. The matching at the next-to-leading order $\alpha_s$ is performed in the $\overline{\rm MS}$ scheme with a complete set of local operators of dimension $d \le 5$, through a manifestly gauge-invariant calculation organizing all contributions in the coordinate space. The result exhibits the Wilson coefficients with Sudakov-type double logarithms and the higher-dimensional operators with additional gluons. This OPE yields the $B$-meson LCDA for $t$ less than $\sim 1$ GeV$^{-1}$, in terms of $\bar{\Lambda}= m_B - m_b$ and the two additional HQET parameters as matrix elements of dimension-5 operators. The impact of these novel HQET parameters on the integral relevant to exclusive $B$ decays, $\lambda_B$, is also discussed.
hep-ph/0407253
Cosmin Macesanu
Cosmin Macesanu, Satyanarayan Nandi, Marius Rujoiu
Single Kaluza Klein Production in Universal Extra Dimensions
11 pages, 6 figures, latex
Phys.Rev. D71 (2005) 036003
10.1103/PhysRevD.71.036003
null
hep-ph
null
In the universal extra dimensions models, Kaluza Klein excitations of matter are generaly produced in pairs. However, if matter lives on a fat brane embedded in a larger space, gravity-matter interactions do not obey KK number conservation, thus making possible the production of single KK excitations at colliders. We evaluate the production rates for such excitations at the Tevatron and LHC colliders, and look for ways to detect them.
[ { "created": "Wed, 21 Jul 2004 19:14:14 GMT", "version": "v1" } ]
2009-11-10
[ [ "Macesanu", "Cosmin", "" ], [ "Nandi", "Satyanarayan", "" ], [ "Rujoiu", "Marius", "" ] ]
In the universal extra dimensions models, Kaluza Klein excitations of matter are generaly produced in pairs. However, if matter lives on a fat brane embedded in a larger space, gravity-matter interactions do not obey KK number conservation, thus making possible the production of single KK excitations at colliders. We evaluate the production rates for such excitations at the Tevatron and LHC colliders, and look for ways to detect them.
0807.2322
Joseph Manjavidze
J. Manjavidze
On phase transition signal in inelastic collision
6 pages, no figures, LaTex
null
null
null
hep-ph
http://creativecommons.org/licenses/publicdomain/
The paper is devoted to retrieval of the first order phase transition signal in the inelastic collisions. The primary intent is to show that the experimentally observable signal exist iff the multiplicity is sufficiently large. We discuss corresponding phenomenology from point of view of the experiment.
[ { "created": "Tue, 15 Jul 2008 08:56:34 GMT", "version": "v1" }, { "created": "Thu, 17 Jul 2008 09:36:27 GMT", "version": "v2" } ]
2008-07-17
[ [ "Manjavidze", "J.", "" ] ]
The paper is devoted to retrieval of the first order phase transition signal in the inelastic collisions. The primary intent is to show that the experimentally observable signal exist iff the multiplicity is sufficiently large. We discuss corresponding phenomenology from point of view of the experiment.
1606.02996
Ismail Zahed
Yizhuang Liu, Edward Shuryak and Ismail Zahed
The Instanton-Dyon Liquid Model V: Twisted Light Quarks
12 pages, 2 figures
Phys. Rev. D 94, 105013 (2016)
10.1103/PhysRevD.94.105013
null
hep-ph hep-lat hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We discuss an extension of the instanton-dyon liquid model that includes twisted light quarks in the fundamental representation with explicit $Z_{N_c}$ symmetry for the case with equal number of colors $N_c$ and flavors $N_f$. We map the model on a 3-dimensional quantum effective theory, and analyze it in the mean-field approximation. The effective potential and the vacuum chiral condensates are made explicit for $N_f=N_c=2, 3$. The low temperature phase is center symmetric but breaks spontaneously flavor symmetry with $N_f-1$ massless pions. The high temperature phase breaks center symmetry but supports finite and unequal quark condensates.
[ { "created": "Thu, 9 Jun 2016 15:24:19 GMT", "version": "v1" } ]
2016-11-23
[ [ "Liu", "Yizhuang", "" ], [ "Shuryak", "Edward", "" ], [ "Zahed", "Ismail", "" ] ]
We discuss an extension of the instanton-dyon liquid model that includes twisted light quarks in the fundamental representation with explicit $Z_{N_c}$ symmetry for the case with equal number of colors $N_c$ and flavors $N_f$. We map the model on a 3-dimensional quantum effective theory, and analyze it in the mean-field approximation. The effective potential and the vacuum chiral condensates are made explicit for $N_f=N_c=2, 3$. The low temperature phase is center symmetric but breaks spontaneously flavor symmetry with $N_f-1$ massless pions. The high temperature phase breaks center symmetry but supports finite and unequal quark condensates.
hep-ph/0701162
Philipe Mota
Ph. Mota, G. S. Denicol, T. Koide and T. Kodama
New Formulation of Causal Dissipative Hydrodynamics: Shock wave propagation
4 pages, 1 figure, Proceedings of Quark Matter 2006
J.Phys.G34:S1011,2007
10.1088/0954-3899/34/8/S145
null
hep-ph
null
The first 3D calculation of shock wave propagation in a homogeneous QGP has been performed within the new formulation of relativistic dissipative hydrodynamics which preserves the causality. We found that the relaxation time plays an important role and also affects the angle of Mach cone.
[ { "created": "Fri, 19 Jan 2007 19:14:59 GMT", "version": "v1" } ]
2008-11-26
[ [ "Mota", "Ph.", "" ], [ "Denicol", "G. S.", "" ], [ "Koide", "T.", "" ], [ "Kodama", "T.", "" ] ]
The first 3D calculation of shock wave propagation in a homogeneous QGP has been performed within the new formulation of relativistic dissipative hydrodynamics which preserves the causality. We found that the relaxation time plays an important role and also affects the angle of Mach cone.
0709.0858
David G. Cerdeno
D. G. Cerdeno, T. Kobayashi, C. Munoz
Prospects for the direct detection of neutralino dark matter in orbifold scenarios
51 pages, 25 figures
JHEP0801:009,2008
10.1088/1126-6708/2008/01/009
FTUAM 07/02, IFT-UAM/CSIC-07-09, KUNS-2091
hep-ph hep-th
null
We analyse the phenomenology of orbifold scenarios from the heterotic superstring, and the resulting theoretical predictions for the direct detection of neutralino dark matter. In particular, we study the parameter space of these constructions, computing the low-energy spectrum and taking into account the most recent experimental and astrophysical constraints, as well as imposing the absence of dangerous charge and colour breaking minima. In the remaining allowed regions the spin-independent part of the neutralino-proton cross section is calculated and compared with the sensitivity of dark matter detectors. In addition to the usual non universalities of the soft terms in orbifold scenarios due to the modular weight dependence, we also consider D-term contributions to scalar masses. These are generated by the presence of an anomalous U(1), providing more flexibility in the resulting soft terms, and are crucial in order to avoid charge and colour breaking minima. Thanks to the D-term contribution, large neutralino detection cross sections can be found, within the reach of projected dark matter detectors.
[ { "created": "Thu, 6 Sep 2007 13:01:32 GMT", "version": "v1" } ]
2008-11-26
[ [ "Cerdeno", "D. G.", "" ], [ "Kobayashi", "T.", "" ], [ "Munoz", "C.", "" ] ]
We analyse the phenomenology of orbifold scenarios from the heterotic superstring, and the resulting theoretical predictions for the direct detection of neutralino dark matter. In particular, we study the parameter space of these constructions, computing the low-energy spectrum and taking into account the most recent experimental and astrophysical constraints, as well as imposing the absence of dangerous charge and colour breaking minima. In the remaining allowed regions the spin-independent part of the neutralino-proton cross section is calculated and compared with the sensitivity of dark matter detectors. In addition to the usual non universalities of the soft terms in orbifold scenarios due to the modular weight dependence, we also consider D-term contributions to scalar masses. These are generated by the presence of an anomalous U(1), providing more flexibility in the resulting soft terms, and are crucial in order to avoid charge and colour breaking minima. Thanks to the D-term contribution, large neutralino detection cross sections can be found, within the reach of projected dark matter detectors.
0812.4878
Vladimir Kopeliovich Benedikt
Vladimir B. Kopeliovich (Moscow, INR)
Selected problems of baryons spectroscopy: chiral soliton versus quark models
18 pages, 6 figures. Based partly on the talks at the Workshop NP08, Mito, Japan, March 05-07, 2008;15th International Seminar Quarks-2008, Sergiev Posad, Russia, May 23-29 and at the International Workshop HSQCD'2008, Gatchina, Russia, June 30 - July 4, 2008
J.Exp.Theor.Phys.108:770-783,2009; Zh.Eksp.Teor.Fiz.135:885-898,2009
10.1134/S1063776109050069
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Inconsistency between rigid rotator and bound state models at arbitrary number of colors, rigid rotator -- soft rotator dilemma and some other problems of baryon spectroscopy are discussed in the framework of the chiral soliton approach (CSA). Consequences of the comparison of CSA results with simple quark models are considered and the $1/N_c$ expansion for the effective strange antiquark mass is presented, as it follows from the CSA. Strong dependence of the effective strange antiquark mass on the SU(3) multiplet is required to fit the CSA predictions. The difference of `good' and `bad' diquark masses, which is about 100 Mev, is in reasonable agreement with other estimates. Multibaryons (hypernuclei) with strangeness are described and some states of interest are predicted within CSA as well.
[ { "created": "Mon, 29 Dec 2008 07:51:00 GMT", "version": "v1" } ]
2011-02-02
[ [ "Kopeliovich", "Vladimir B.", "", "Moscow, INR" ] ]
Inconsistency between rigid rotator and bound state models at arbitrary number of colors, rigid rotator -- soft rotator dilemma and some other problems of baryon spectroscopy are discussed in the framework of the chiral soliton approach (CSA). Consequences of the comparison of CSA results with simple quark models are considered and the $1/N_c$ expansion for the effective strange antiquark mass is presented, as it follows from the CSA. Strong dependence of the effective strange antiquark mass on the SU(3) multiplet is required to fit the CSA predictions. The difference of `good' and `bad' diquark masses, which is about 100 Mev, is in reasonable agreement with other estimates. Multibaryons (hypernuclei) with strangeness are described and some states of interest are predicted within CSA as well.
2203.04983
Ahmed Youssef
Phil Ilten, Tony Menzo, Ahmed Youssef, Jure Zupan
Modeling hadronization using machine learning
24 pages, 12 figures, public code available
null
null
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
We present the first steps in the development of a new class of hadronization models utilizing machine learning techniques. We successfully implement, validate, and train a conditional sliced-Wasserstein autoencoder to replicate the Pythia generated kinematic distributions of first-hadron emissions, when the Lund string model of hadronization implemented in Pythia is restricted to the emissions of pions only. The trained models are then used to generate the full hadronization chains, with an IR cutoff energy imposed externally. The hadron multiplicities and cumulative kinematic distributions are shown to match the Pythia generated ones. We also discuss possible future generalizations of our results.
[ { "created": "Wed, 9 Mar 2022 19:00:02 GMT", "version": "v1" } ]
2022-03-11
[ [ "Ilten", "Phil", "" ], [ "Menzo", "Tony", "" ], [ "Youssef", "Ahmed", "" ], [ "Zupan", "Jure", "" ] ]
We present the first steps in the development of a new class of hadronization models utilizing machine learning techniques. We successfully implement, validate, and train a conditional sliced-Wasserstein autoencoder to replicate the Pythia generated kinematic distributions of first-hadron emissions, when the Lund string model of hadronization implemented in Pythia is restricted to the emissions of pions only. The trained models are then used to generate the full hadronization chains, with an IR cutoff energy imposed externally. The hadron multiplicities and cumulative kinematic distributions are shown to match the Pythia generated ones. We also discuss possible future generalizations of our results.
0804.4779
Peter Renton
Peter Renton
Updated SM calculations of sigma_W/sigma_Z at the Tevatron and the W boson width
6 pages
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The central value and theoretical uncertainties on the cross section ratio sigma_W/sigma_Z at the Tevatron are evaluated using the NNLO calculations and the latest MSTW PDFs. The partial width, total width and branching ratios of the W boson in the Standard Model, in the light of the latest electroweak calculations, are also updated.
[ { "created": "Wed, 30 Apr 2008 10:35:42 GMT", "version": "v1" } ]
2012-03-15
[ [ "Renton", "Peter", "" ] ]
The central value and theoretical uncertainties on the cross section ratio sigma_W/sigma_Z at the Tevatron are evaluated using the NNLO calculations and the latest MSTW PDFs. The partial width, total width and branching ratios of the W boson in the Standard Model, in the light of the latest electroweak calculations, are also updated.
1003.0957
Ping Wang
P. Wang, A. W. Thomas
The First Moments of Nucleon Generalized Parton Distributions
14 pages, 9 figures
Phys.Rev.D81:114015,2010
10.1103/PhysRevD.81.114015
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We extrapolate the first moments of the generalized parton distributions using heavy baryon chiral perturbation theory. The calculation is based on the one loop level with the finite range regularization. The description of the lattice data is satisfactory and the extrapolated moments at physical pion mass are consistent with the results obtained with dimensional regularization, although the extrapolation in the momentum transfer to $t=0$ does show sensitivity to form factor effects which lie outside the realm of chiral perturbation theory. We discuss the significance of the results in the light of modern experiments as well as QCD inspired models.
[ { "created": "Thu, 4 Mar 2010 03:12:06 GMT", "version": "v1" }, { "created": "Thu, 27 May 2010 11:53:28 GMT", "version": "v2" } ]
2014-11-20
[ [ "Wang", "P.", "" ], [ "Thomas", "A. W.", "" ] ]
We extrapolate the first moments of the generalized parton distributions using heavy baryon chiral perturbation theory. The calculation is based on the one loop level with the finite range regularization. The description of the lattice data is satisfactory and the extrapolated moments at physical pion mass are consistent with the results obtained with dimensional regularization, although the extrapolation in the momentum transfer to $t=0$ does show sensitivity to form factor effects which lie outside the realm of chiral perturbation theory. We discuss the significance of the results in the light of modern experiments as well as QCD inspired models.
2008.10240
Christian Fischer
Gernot Eichmann, Christian S. Fischer, Walter Heupel, Nico Santowsky and Paul C. Wallbott
Four-quark states from functional methods
19 pages, 9 figures, v2: typos corrected, version accepted by Few Body Syst
null
10.1007/s00601-020-01571-3
null
hep-ph hep-lat
http://creativecommons.org/licenses/by-nc-nd/4.0/
In this feature article we summarise and highlight aspects of the treatment of four-quark states with functional methods. Model approaches to those exotic mesons almost inevitably have to assume certain internal structures, e.g. by grouping quarks and antiquarks into (anti-)diquark clusters or heavy-light $q\bar{q}$ pairs. Functional methods using Dyson-Schwinger and Bethe-Salpeter equations can be formulated without such prejudice and therefore have the potential to put these assumptions to test and discriminate between such models. So far, functional methods have been used to study the light scalar-meson sector and the heavy-light sector with a pair of charmed and a pair of light quarks in different quantum number channels. For all these states, the dominant components in terms of internal two-body clustering have been identified. It turns out that chiral symmetry breaking plays an important role for the dominant clusters in the light meson sector (in particular for the scalar mesons) and that this property is carried over to the heavy-light sector. Diquark-antidiquark components, on the other hand, turn out to be almost negligible for most states with the exception of open-charm heavy-light exotics.
[ { "created": "Mon, 24 Aug 2020 07:57:25 GMT", "version": "v1" }, { "created": "Wed, 1 Sep 2021 07:08:51 GMT", "version": "v2" } ]
2021-09-02
[ [ "Eichmann", "Gernot", "" ], [ "Fischer", "Christian S.", "" ], [ "Heupel", "Walter", "" ], [ "Santowsky", "Nico", "" ], [ "Wallbott", "Paul C.", "" ] ]
In this feature article we summarise and highlight aspects of the treatment of four-quark states with functional methods. Model approaches to those exotic mesons almost inevitably have to assume certain internal structures, e.g. by grouping quarks and antiquarks into (anti-)diquark clusters or heavy-light $q\bar{q}$ pairs. Functional methods using Dyson-Schwinger and Bethe-Salpeter equations can be formulated without such prejudice and therefore have the potential to put these assumptions to test and discriminate between such models. So far, functional methods have been used to study the light scalar-meson sector and the heavy-light sector with a pair of charmed and a pair of light quarks in different quantum number channels. For all these states, the dominant components in terms of internal two-body clustering have been identified. It turns out that chiral symmetry breaking plays an important role for the dominant clusters in the light meson sector (in particular for the scalar mesons) and that this property is carried over to the heavy-light sector. Diquark-antidiquark components, on the other hand, turn out to be almost negligible for most states with the exception of open-charm heavy-light exotics.
hep-ph/9610296
Ian Jack
P.M. Ferreira, I. Jack and D.R.T. Jones
The Quasi-Infra-Red Fixed Point at Higher Loops
12 pages, including 3 figures. Version as published in Phys. Lett. B, but with minor errors corrected, particularly f(T)-->f(0). Plain TeX. Uses Harvmac and epsf
Phys.Lett. B392 (1997) 376-382
10.1016/S0370-2693(96)01549-3
LTH 386
hep-ph
null
We calculate the four-loop $\beta$-function for the generalised Wess-Zumino model. We use the result and Pad\'e-Borel summation to discuss the domain of attraction of the quasi-infra-red fixed point of the top-quark Yukawa coupling in the supersymmetric standard model, and argue that the domain is in fact substantial.
[ { "created": "Wed, 9 Oct 1996 09:30:39 GMT", "version": "v1" }, { "created": "Fri, 27 Dec 1996 14:33:20 GMT", "version": "v2" }, { "created": "Fri, 3 Jan 1997 17:13:45 GMT", "version": "v3" }, { "created": "Tue, 29 Jun 1999 16:00:34 GMT", "version": "v4" } ]
2009-10-28
[ [ "Ferreira", "P. M.", "" ], [ "Jack", "I.", "" ], [ "Jones", "D. R. T.", "" ] ]
We calculate the four-loop $\beta$-function for the generalised Wess-Zumino model. We use the result and Pad\'e-Borel summation to discuss the domain of attraction of the quasi-infra-red fixed point of the top-quark Yukawa coupling in the supersymmetric standard model, and argue that the domain is in fact substantial.
hep-ph/0104158
Archil Kobakhidze
Masud Chaichian and Archil. B. Kobakhidze
Extra dimensions and the strong CP problem
7 pp., latex, no figures
Phys.Rev.Lett.87:171601,2001
10.1103/PhysRevLett.87.171601
HIP-2001-10/TH
hep-ph
null
In higher-dimensional theories such as Brane World models with quasi-localized non-Abelian gauge fields the vacuum structure turns out to be trivial. Since the gauge theory behaves at large distances as a $4+\delta$-dimensional and thus the topology of the infinity is that of of $S^{3+\delta}$ rather than $S^{3}$, the set of gauge mappings are homotopically trivial and the CP-violating $\theta$-term vanishes on the brane world-volume. As well there are no contributions to the $\theta$-term from the higher-dimensional solitonic configurations. In this way, the strong CP problem is absent in the models with quasi-localized gluons.
[ { "created": "Tue, 17 Apr 2001 10:52:04 GMT", "version": "v1" } ]
2014-11-17
[ [ "Chaichian", "Masud", "" ], [ "Kobakhidze", "Archil. B.", "" ] ]
In higher-dimensional theories such as Brane World models with quasi-localized non-Abelian gauge fields the vacuum structure turns out to be trivial. Since the gauge theory behaves at large distances as a $4+\delta$-dimensional and thus the topology of the infinity is that of of $S^{3+\delta}$ rather than $S^{3}$, the set of gauge mappings are homotopically trivial and the CP-violating $\theta$-term vanishes on the brane world-volume. As well there are no contributions to the $\theta$-term from the higher-dimensional solitonic configurations. In this way, the strong CP problem is absent in the models with quasi-localized gluons.
hep-ph/9611316
Hong-Jian He
H.-J. He (DESY), Y.-P. Kuang (Tsinghua), C.-P. Yuan (MSU)
Estimating The Sensitivity Of The LHC To Electroweak Symmetry Breaking: Longitudinal-Goldstone Boson Equivalence As A Criterion
Version to be Published in Phys.Rev.D. RevTex, 70-pages, including 22 individual Figs put in 13 PS-files, (Combined PS-Figs in one Postscript is avaiable from http://xxx.lanl.gov/ps/hep-ph/9611316)
Phys.Rev. D55 (1997) 3038-3067
10.1103/PhysRevD.55.3038
DESY-96-148, TUIMP-TH-96/78, MSUHEP-60615
hep-ph
null
Based upon our recent study, we reveal the profound physical content of the longitudinal-Goldstone boson equivalence theorem as being able to discriminate physical processes which are sensitive/insensitive to probing the electroweak symmetry breaking (EWSB) sector. We then develop a precise electroweak power counting rule (a generalization from Weinberg's counting method) to `separately' count the power dependences on the energy E and all relevant mass scales. With these, we analyze the complete set of the bosonic operators in the electroweak chiral Lagrangian and systematically estimate and classify the sensitivities for testing all these effective operators at the CERN LHC via the weak-boson fusions and quark-anti-quark annihilations. These two kinds of processes are shown to be `complementary' in probing the EWSB mechanism.
[ { "created": "Wed, 13 Nov 1996 16:30:55 GMT", "version": "v1" } ]
2009-10-30
[ [ "He", "H. -J.", "", "DESY" ], [ "Kuang", "Y. -P.", "", "Tsinghua" ], [ "Yuan", "C. -P.", "", "MSU" ] ]
Based upon our recent study, we reveal the profound physical content of the longitudinal-Goldstone boson equivalence theorem as being able to discriminate physical processes which are sensitive/insensitive to probing the electroweak symmetry breaking (EWSB) sector. We then develop a precise electroweak power counting rule (a generalization from Weinberg's counting method) to `separately' count the power dependences on the energy E and all relevant mass scales. With these, we analyze the complete set of the bosonic operators in the electroweak chiral Lagrangian and systematically estimate and classify the sensitivities for testing all these effective operators at the CERN LHC via the weak-boson fusions and quark-anti-quark annihilations. These two kinds of processes are shown to be `complementary' in probing the EWSB mechanism.
hep-ph/0107088
U. Meissner
V\'eronique Bernard, Latifa Elouadrhiri, Ulf-G. Mei{\ss}ner
Axial structure of the nucleon
40 pp, uses iopart.cls, iopart10.clo, iopart12.clo
J.Phys.G28:R1-R35,2002
10.1088/0954-3899/28/1/201
null
hep-ph hep-ex nucl-ex nucl-th
null
We review the current status of experimental and theoretical understanding of the axial nucleon structure at low and moderate energies. Topics considered include (quasi)elastic (anti)neutrino-nucleon scattering, charged pion electroproduction off nucleons and ordinary as well as radiative muon capture on the proton.
[ { "created": "Mon, 9 Jul 2001 12:34:19 GMT", "version": "v1" } ]
2015-06-25
[ [ "Bernard", "Véronique", "" ], [ "Elouadrhiri", "Latifa", "" ], [ "Meißner", "Ulf-G.", "" ] ]
We review the current status of experimental and theoretical understanding of the axial nucleon structure at low and moderate energies. Topics considered include (quasi)elastic (anti)neutrino-nucleon scattering, charged pion electroproduction off nucleons and ordinary as well as radiative muon capture on the proton.
2403.19025
Roy Aleksan
Roy Aleksan and Luis Oliver
Analysis of data on $B$ decays into two light vector mesons
arXiv admin note: text overlap with arXiv:2205.07823
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
An important experimental effort has been accomplished in recent years in the measurement of rates, polarization and CP observables in $B$ decays into two light vector mesons. On the theoretical side, after a very consistent effort done within the framework of QCD Factorization, the comparison of the theory with the present experimental data has not been updated, to our knowledge. In the present paper we compare this wealth of data to the theory, in tree color-allowed, tree color-suppressed and pure penguin decays, and present predictions for the observables that have not yet been measured in these decays. In our fits we find acceptable values of $\chi^2$ for the branching ratios and for the direct CP asymmetries. However, this is not the case for the longitudinal polarization fractions, essentially due to disagreement between theory and experiment for the modes $B_{d,s}\to K^{*0}\overline{K}^{*0}$ and $B_d \to \rho^+ \rho^-$. Although we rely on previous work by other authors, we summarize the formalism so that the paper is self-contained and its results can be checked.
[ { "created": "Wed, 27 Mar 2024 21:36:05 GMT", "version": "v1" } ]
2024-03-29
[ [ "Aleksan", "Roy", "" ], [ "Oliver", "Luis", "" ] ]
An important experimental effort has been accomplished in recent years in the measurement of rates, polarization and CP observables in $B$ decays into two light vector mesons. On the theoretical side, after a very consistent effort done within the framework of QCD Factorization, the comparison of the theory with the present experimental data has not been updated, to our knowledge. In the present paper we compare this wealth of data to the theory, in tree color-allowed, tree color-suppressed and pure penguin decays, and present predictions for the observables that have not yet been measured in these decays. In our fits we find acceptable values of $\chi^2$ for the branching ratios and for the direct CP asymmetries. However, this is not the case for the longitudinal polarization fractions, essentially due to disagreement between theory and experiment for the modes $B_{d,s}\to K^{*0}\overline{K}^{*0}$ and $B_d \to \rho^+ \rho^-$. Although we rely on previous work by other authors, we summarize the formalism so that the paper is self-contained and its results can be checked.
hep-ph/9907467
Marco Stratmann
M. Stratmann (Durham Univ.)
Probing the parton densities of polarized photons at a linear e^+e^- collider
7 pages, LaTeX, 4 eps figures, uses amssymb, espcrc2 (included), and epsfig styles; Contribution to the Proceedings of the `International Conference on the Structure and Interactions of the Photon (Photon99)' [Nucl. Phys. B (Proc. Suppl.)], Freiburg, Germany, May 1999
Nucl.Phys.Proc.Suppl. 82 (2000) 400-406
10.1016/S0920-5632(00)00185-7
DTP/99/84
hep-ph
null
The present theoretical status of spin-dependent parton densities Delta f^{\gamma}(x,Q^2) of circularly polarized photons is briefly reviewed. It is then demonstrated that measurements of the deep-inelastic spin asymmetry A_1^{\gamma}\simeq g_1^{\gamma}/F_1^{\gamma} and of di-jet rapidity distributions at a future linear e^+e^- collider appear to be particularly suited for a determination the spin-dependent photonic quark and gluon densities, respectively. Special emphasis is devoted to a comparison of the different sources of polarized photons at a linear collider: the equivalent photon approximation and backscattered laser (Compton) photons. It is shown that backscattered laser photons are highly favorable, even indispensable, for decent measurements of the Delta f^{\gamma}(x,Q^2).
[ { "created": "Fri, 23 Jul 1999 11:25:18 GMT", "version": "v1" } ]
2009-10-31
[ [ "Stratmann", "M.", "", "Durham Univ." ] ]
The present theoretical status of spin-dependent parton densities Delta f^{\gamma}(x,Q^2) of circularly polarized photons is briefly reviewed. It is then demonstrated that measurements of the deep-inelastic spin asymmetry A_1^{\gamma}\simeq g_1^{\gamma}/F_1^{\gamma} and of di-jet rapidity distributions at a future linear e^+e^- collider appear to be particularly suited for a determination the spin-dependent photonic quark and gluon densities, respectively. Special emphasis is devoted to a comparison of the different sources of polarized photons at a linear collider: the equivalent photon approximation and backscattered laser (Compton) photons. It is shown that backscattered laser photons are highly favorable, even indispensable, for decent measurements of the Delta f^{\gamma}(x,Q^2).
1911.05738
Alexis Plascencia
Pavel Fileviez Perez, Clara Murgui and Alexis D. Plascencia
Axion Dark Matter, Proton Decay and Unification
17 pages, 4 figures. v2: minor comments and references added, matches version published in JHEP
JHEP(2020) 2020: 91
10.1007/JHEP01(2020)091
null
hep-ph hep-ex
http://creativecommons.org/licenses/by/4.0/
We discuss the possibility to predict the QCD axion mass in the context of grand unified theories. We investigate the implementation of the DFSZ mechanism in the context of renormalizable SU(5) theories. In the simplest theory, the axion mass can be predicted with good precision in the range $m_a = (2-16)$ neV, and there is a strong correlation between the predictions for the axion mass and proton decay rates. In this context, we predict an upper bound for the proton decay channels with antineutrinos, $\tau(p\to K^+ \bar{\nu}) \lesssim 4 \times 10^{37} \text{ yr}$ and $\tau(p \to \pi^+ \bar{\nu}) \lesssim 2 \times 10^{36}\text{ yr}$. This theory can be considered as the minimal realistic grand unified theory with the DFSZ mechanism and it can be fully tested by proton decay and axion experiments.
[ { "created": "Wed, 13 Nov 2019 19:00:00 GMT", "version": "v1" }, { "created": "Sat, 21 Dec 2019 01:22:59 GMT", "version": "v2" } ]
2020-01-22
[ [ "Perez", "Pavel Fileviez", "" ], [ "Murgui", "Clara", "" ], [ "Plascencia", "Alexis D.", "" ] ]
We discuss the possibility to predict the QCD axion mass in the context of grand unified theories. We investigate the implementation of the DFSZ mechanism in the context of renormalizable SU(5) theories. In the simplest theory, the axion mass can be predicted with good precision in the range $m_a = (2-16)$ neV, and there is a strong correlation between the predictions for the axion mass and proton decay rates. In this context, we predict an upper bound for the proton decay channels with antineutrinos, $\tau(p\to K^+ \bar{\nu}) \lesssim 4 \times 10^{37} \text{ yr}$ and $\tau(p \to \pi^+ \bar{\nu}) \lesssim 2 \times 10^{36}\text{ yr}$. This theory can be considered as the minimal realistic grand unified theory with the DFSZ mechanism and it can be fully tested by proton decay and axion experiments.
hep-ph/0604229
Pasquale Migliozzi Dr.
A. Donini, E. Fernandez-Martinez, P. Migliozzi, S. Rigolin, L. Scotto Lavina, T. Tabarelli de Fatis, F. Terranova
A Beta Beam complex based on the machine upgrades for the LHC
null
Eur.Phys.J.C48:787-796,2006
10.1140/epjc/s10052-006-0019-3
null
hep-ph
null
The Beta Beam CERN design is based on the present LHC injection complex and its physics reach is mainly limited by the maximum rigidity of the SPS. In fact, some of the scenarios for the machine upgrades of the LHC, particularly the construction of a fast cycling 1 TeV injector (``Super-SPS''), are very synergic with the construction of a higher $\gamma$ Beta Beam. At the energies that can be reached by this machine, we demonstrate that dense calorimeters can already be used for the detection of $\nu$ at the far location. Even at moderate masses (40 kton) as the ones imposed by the use of existing underground halls at Gran Sasso, the CP reach is very large for any value of $\theta_{13}$ that would provide evidence of $\nu_e$ appearance at T2K or NO$\nu$A ($\theta_{13}\geq 3^\circ$). Exploitation of matter effects at the CERN to Gran Sasso distance provides sensitivity to the neutrino mass hierarchy in significant areas of the $\theta_{13}-\delta$ plane.
[ { "created": "Wed, 26 Apr 2006 13:44:57 GMT", "version": "v1" }, { "created": "Wed, 12 Jul 2006 13:13:08 GMT", "version": "v2" } ]
2011-09-13
[ [ "Donini", "A.", "" ], [ "Fernandez-Martinez", "E.", "" ], [ "Migliozzi", "P.", "" ], [ "Rigolin", "S.", "" ], [ "Lavina", "L. Scotto", "" ], [ "de Fatis", "T. Tabarelli", "" ], [ "Terranova", "F.", "" ] ]
The Beta Beam CERN design is based on the present LHC injection complex and its physics reach is mainly limited by the maximum rigidity of the SPS. In fact, some of the scenarios for the machine upgrades of the LHC, particularly the construction of a fast cycling 1 TeV injector (``Super-SPS''), are very synergic with the construction of a higher $\gamma$ Beta Beam. At the energies that can be reached by this machine, we demonstrate that dense calorimeters can already be used for the detection of $\nu$ at the far location. Even at moderate masses (40 kton) as the ones imposed by the use of existing underground halls at Gran Sasso, the CP reach is very large for any value of $\theta_{13}$ that would provide evidence of $\nu_e$ appearance at T2K or NO$\nu$A ($\theta_{13}\geq 3^\circ$). Exploitation of matter effects at the CERN to Gran Sasso distance provides sensitivity to the neutrino mass hierarchy in significant areas of the $\theta_{13}-\delta$ plane.
1204.0445
Daniel Hern\'andez
D. Hernandez and A. Yu. Smirnov
Lepton mixing and discrete symmetries
16 pages, 2 figures, new material added. Several points clarified
null
10.1103/PhysRevD.86.053014
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The pattern of lepton mixing can emerge from breaking a flavor symmetry in different ways in the neutrino and charged lepton Yukawa sectors. In this framework, we derive the conditions imposed on the mixing matrix by the structure of discrete groups of the von Dyck type which include A4, S4 and A5. We show that, in general, these conditions reduce to two equations for the mixing parameters (angles and CP phase \delta). These constraints, which correspond to unbroken residual symmetries, are consistent with non-zero 13 mixing and deviations from maximal 2-3 mixing. For the allowed values of mixing angles we predict \delta = 60 - 90^{\circ}.
[ { "created": "Mon, 2 Apr 2012 15:57:35 GMT", "version": "v1" }, { "created": "Wed, 4 Apr 2012 16:29:25 GMT", "version": "v2" }, { "created": "Thu, 19 Apr 2012 21:36:27 GMT", "version": "v3" }, { "created": "Wed, 25 Jul 2012 00:26:00 GMT", "version": "v4" } ]
2013-05-30
[ [ "Hernandez", "D.", "" ], [ "Smirnov", "A. Yu.", "" ] ]
The pattern of lepton mixing can emerge from breaking a flavor symmetry in different ways in the neutrino and charged lepton Yukawa sectors. In this framework, we derive the conditions imposed on the mixing matrix by the structure of discrete groups of the von Dyck type which include A4, S4 and A5. We show that, in general, these conditions reduce to two equations for the mixing parameters (angles and CP phase \delta). These constraints, which correspond to unbroken residual symmetries, are consistent with non-zero 13 mixing and deviations from maximal 2-3 mixing. For the allowed values of mixing angles we predict \delta = 60 - 90^{\circ}.
hep-ph/9508376
null
Guo-Hong Wu
Nonoblique Effects and Weak-Isospin Breaking from Extended Technicolor
Talk given at the Top Quark Workshop, Iowa State University, May 25-26, 1995, 6 pages, use WSPRL.STY
null
null
YCTP-P13-95
hep-ph
null
Several aspects of the flavor-diagonal extended technicolor (ETC) gauge boson are reviewed. Among them are an increase of $R_b$ that could explain the LEP $R_b$ excess, a sizable, positive correction to the $\tau$ asymmetry parameter $A_{\tau}$, and a contribution to the weak-isospin breaking $\rho$ parameter that is just barely acceptable by present data.
[ { "created": "Sun, 27 Aug 1995 04:57:18 GMT", "version": "v1" } ]
2007-05-23
[ [ "Wu", "Guo-Hong", "" ] ]
Several aspects of the flavor-diagonal extended technicolor (ETC) gauge boson are reviewed. Among them are an increase of $R_b$ that could explain the LEP $R_b$ excess, a sizable, positive correction to the $\tau$ asymmetry parameter $A_{\tau}$, and a contribution to the weak-isospin breaking $\rho$ parameter that is just barely acceptable by present data.
1701.08322
Ilja Dor\v{s}ner
Ilja Dor\v{s}ner, Svjetlana Fajfer, Nejc Ko\v{s}nik
Leptoquark mechanism of neutrino masses within the grand unification framework
minor typos fixed, 14 pages, 1 figure
null
10.1140/epjc/s10052-017-4987-2
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We demonstrate viability of the one-loop neutrino mass mechanism within the framework of grand unification when the loop particles comprise scalar leptoquarks (LQs) and quarks of the matching electric charge. This mechanism can be implemented in both supersymmetric and non-supersymmetric models and requires the presence of at least one LQ pair. The appropriate pairs for the neutrino mass generation via the up-type and down-type quark loops are $S_3$-$R_2$ and $S_{1,\,3}$-$\tilde{R}_2$, respectively. We consider two phenomenologically distinct regimes for the LQ masses in our analysis. First regime calls for very heavy LQs in the loop. It can be naturally realised with the $S_{1,\,3}$-$\tilde{R}_2$ scenarios when the LQ masses are roughly between $10^{12}$ GeV and $5 \times 10^{13}$ GeV. These lower and upper bounds originate from experimental limits on partial proton decay lifetimes and perturbativity constraints, respectively. Second regime corresponds to the collider accessible LQs in the neutrino mass loop. That option is viable for the $S_3$-$\tilde{R}_2$ scenario in the models of unification that we discuss. If one furthermore assumes the presence of the type II see-saw mechanism there is an additional contribution from the $S_3$-$R_2$ scenario that needs to be taken into account beside the type II see-saw contribution itself. We provide a complete list of renormalizable operators that yield necessary mixing of all aforementioned LQ pairs using the language of $SU(5)$. We furthermore discuss several possible embeddings of this mechanism in $SU(5)$ and $SO(10)$ gauge groups.
[ { "created": "Sat, 28 Jan 2017 21:30:22 GMT", "version": "v1" }, { "created": "Thu, 16 Feb 2017 14:22:29 GMT", "version": "v2" } ]
2017-08-02
[ [ "Doršner", "Ilja", "" ], [ "Fajfer", "Svjetlana", "" ], [ "Košnik", "Nejc", "" ] ]
We demonstrate viability of the one-loop neutrino mass mechanism within the framework of grand unification when the loop particles comprise scalar leptoquarks (LQs) and quarks of the matching electric charge. This mechanism can be implemented in both supersymmetric and non-supersymmetric models and requires the presence of at least one LQ pair. The appropriate pairs for the neutrino mass generation via the up-type and down-type quark loops are $S_3$-$R_2$ and $S_{1,\,3}$-$\tilde{R}_2$, respectively. We consider two phenomenologically distinct regimes for the LQ masses in our analysis. First regime calls for very heavy LQs in the loop. It can be naturally realised with the $S_{1,\,3}$-$\tilde{R}_2$ scenarios when the LQ masses are roughly between $10^{12}$ GeV and $5 \times 10^{13}$ GeV. These lower and upper bounds originate from experimental limits on partial proton decay lifetimes and perturbativity constraints, respectively. Second regime corresponds to the collider accessible LQs in the neutrino mass loop. That option is viable for the $S_3$-$\tilde{R}_2$ scenario in the models of unification that we discuss. If one furthermore assumes the presence of the type II see-saw mechanism there is an additional contribution from the $S_3$-$R_2$ scenario that needs to be taken into account beside the type II see-saw contribution itself. We provide a complete list of renormalizable operators that yield necessary mixing of all aforementioned LQ pairs using the language of $SU(5)$. We furthermore discuss several possible embeddings of this mechanism in $SU(5)$ and $SO(10)$ gauge groups.
hep-ph/0509315
Vladimir Zykunov
V. A. Zykunov
Weak radiative corrections to the Drell-Yan process for large invariant mass of a dilepton pair
Changed content; 13 pp, 4 fig, 1 table
Phys.Rev.D75:073019,2007
10.1103/PhysRevD.75.073019
null
hep-ph
null
The weak radiative corrections to the Drell-Yan process above the Z-peak have been studied. The compact asymptotic expression for the two heavy boson exchange - one of the significant contributions to the investigated process - has been obtained, the results expand in the powers of the Sudakov electroweak logarithms. At the quark level we compare the weak radiative corrections to the total cross section and forward-backward asymmetry with the existing results and achieve a rather good coincidence at \sqrt{s}>= 0.5 TeV. The numerical analysis has been performed in the high energy region corresponding to the future experiments at the CERN Large Hadron Collider (LHC). To simulate the detector acceptance we used the standard CMS detector cuts. It was shown that double Sudakov logarithms of the WW boxes are the dominant contributions in hadronic cross section. The considered radiative corrections are significant at high dilepton mass M and change the dilepton mass distribution up to ~+3(-12)% at the LHC energies and M=1(5) TeV.
[ { "created": "Tue, 27 Sep 2005 21:53:47 GMT", "version": "v1" }, { "created": "Thu, 26 Apr 2007 11:24:16 GMT", "version": "v2" } ]
2008-11-26
[ [ "Zykunov", "V. A.", "" ] ]
The weak radiative corrections to the Drell-Yan process above the Z-peak have been studied. The compact asymptotic expression for the two heavy boson exchange - one of the significant contributions to the investigated process - has been obtained, the results expand in the powers of the Sudakov electroweak logarithms. At the quark level we compare the weak radiative corrections to the total cross section and forward-backward asymmetry with the existing results and achieve a rather good coincidence at \sqrt{s}>= 0.5 TeV. The numerical analysis has been performed in the high energy region corresponding to the future experiments at the CERN Large Hadron Collider (LHC). To simulate the detector acceptance we used the standard CMS detector cuts. It was shown that double Sudakov logarithms of the WW boxes are the dominant contributions in hadronic cross section. The considered radiative corrections are significant at high dilepton mass M and change the dilepton mass distribution up to ~+3(-12)% at the LHC energies and M=1(5) TeV.
hep-ph/9911226
Gilberto Tavares-Velasco
G. Tavares-Velasco, J.J. Toscano
Photon photon scattering in a 3-3-1 model
To appear in Europhysics Letters, title changed in journal, minor corrections, one figure added
Europhys.Lett.53:465-470,2001
10.1209/epl/i2001-00175-8
null
hep-ph
null
We analyze the effects of a doubly charged vector bilepton as well as exotic quarks with charge 5/3 e and -4/3 e on light by light scattering. We consider mass values in the range 0.3--1 TeV, which would be reached at the planned future linear colliders. It is found that such exotic particles, especially the doubly charged vector bilepton, give raise to remarkable deviations from the standard model cross section. The virtual effects arising from these particles would provide an indirect test to a particular model which is based on the SU_c(3) X SU_L(3) X U_x(1) gauge symmetry, known as the 331 model, where such particles are a natural prediction.
[ { "created": "Wed, 3 Nov 1999 21:00:47 GMT", "version": "v1" }, { "created": "Fri, 12 Jan 2001 23:44:59 GMT", "version": "v2" } ]
2010-12-17
[ [ "Tavares-Velasco", "G.", "" ], [ "Toscano", "J. J.", "" ] ]
We analyze the effects of a doubly charged vector bilepton as well as exotic quarks with charge 5/3 e and -4/3 e on light by light scattering. We consider mass values in the range 0.3--1 TeV, which would be reached at the planned future linear colliders. It is found that such exotic particles, especially the doubly charged vector bilepton, give raise to remarkable deviations from the standard model cross section. The virtual effects arising from these particles would provide an indirect test to a particular model which is based on the SU_c(3) X SU_L(3) X U_x(1) gauge symmetry, known as the 331 model, where such particles are a natural prediction.
hep-ph/0607208
Pavel Fileviez Perez
Ilja Dorsner, Pavel Fileviez Perez, German Rodrigo
Fermion Masses and the UV Cutoff of the Minimal Realistic SU(5)
15 pages, 5 figures, minor corrections; version to appear in Physical Review D
Phys.Rev.D75:125007,2007
10.1103/PhysRevD.75.125007
null
hep-ph hep-ex hep-th
null
We investigate the predictions for fermion masses in the minimal realistic non-supersymmetric SU(5) model with the Standard Model matter content. The possibility to achieve b-\tau unification is studied taking into account all relevant effects. In addition, we show how to establish an upper bound on the ultraviolet cutoff \Lambda of the theory which is compatible with the Yukawa couplings at the grand unified scale and proton decay. We find \Lambda \simeq 10^{17} GeV, to be considered a conservative upper bound on the cutoff. We also provide up-to-date values of all the fermions masses at the electroweak scale.
[ { "created": "Wed, 19 Jul 2006 11:45:07 GMT", "version": "v1" }, { "created": "Thu, 15 Feb 2007 18:31:38 GMT", "version": "v2" }, { "created": "Wed, 16 May 2007 10:44:17 GMT", "version": "v3" } ]
2007-06-07
[ [ "Dorsner", "Ilja", "" ], [ "Perez", "Pavel Fileviez", "" ], [ "Rodrigo", "German", "" ] ]
We investigate the predictions for fermion masses in the minimal realistic non-supersymmetric SU(5) model with the Standard Model matter content. The possibility to achieve b-\tau unification is studied taking into account all relevant effects. In addition, we show how to establish an upper bound on the ultraviolet cutoff \Lambda of the theory which is compatible with the Yukawa couplings at the grand unified scale and proton decay. We find \Lambda \simeq 10^{17} GeV, to be considered a conservative upper bound on the cutoff. We also provide up-to-date values of all the fermions masses at the electroweak scale.
hep-ph/0611362
Motohiko Yoshimura
M. Yoshimura
Neutrino Pair Emission from Excited Atoms
56 pages, 1 figure added showing the rate. 2 notes added in the end. Several typos are corected from the previous version
Phys.Rev.D75:113007,2007
10.1103/PhysRevD.75.113007
null
hep-ph hep-ex hep-th physics.atom-ph
null
We explore a possibility of measuring the magnitude and the Majorana nature of neutrino masses, by using a novel process of neutrino pair emission from excited atoms. Except lepton number non-conserving processes, the neutrino pair ($\nu \bar{\nu}$) emission is the unique process to distinguish the Majorana neutrino from the Dirac neutrino. The small energy difference between atomic levels makes it easier to measure small neutrino masses as indicated by neutrino oscillation experiments. The crucial point is how to enhance the rate of pair emission without enhancing the radiative decay. We have in mind two particular cases; (1) laser irradiated pair emission from metastable atoms, and (2) microwave irradiated emission from circular Rydberg states. A new mechanism of the parametric amplification to enhance the neutrino pair emission is pointed out when Rydberg atoms are irradiated by microwave, while the radiative process may be inhibited by the cavity QED effect. A great variety of measurable neutrino parameters and a variety of experimental methods are conceivable.
[ { "created": "Wed, 29 Nov 2006 07:33:39 GMT", "version": "v1" }, { "created": "Thu, 21 Dec 2006 00:38:38 GMT", "version": "v2" }, { "created": "Mon, 25 Dec 2006 05:35:44 GMT", "version": "v3" }, { "created": "Wed, 6 Jun 2007 06:20:29 GMT", "version": "v4" } ]
2008-11-26
[ [ "Yoshimura", "M.", "" ] ]
We explore a possibility of measuring the magnitude and the Majorana nature of neutrino masses, by using a novel process of neutrino pair emission from excited atoms. Except lepton number non-conserving processes, the neutrino pair ($\nu \bar{\nu}$) emission is the unique process to distinguish the Majorana neutrino from the Dirac neutrino. The small energy difference between atomic levels makes it easier to measure small neutrino masses as indicated by neutrino oscillation experiments. The crucial point is how to enhance the rate of pair emission without enhancing the radiative decay. We have in mind two particular cases; (1) laser irradiated pair emission from metastable atoms, and (2) microwave irradiated emission from circular Rydberg states. A new mechanism of the parametric amplification to enhance the neutrino pair emission is pointed out when Rydberg atoms are irradiated by microwave, while the radiative process may be inhibited by the cavity QED effect. A great variety of measurable neutrino parameters and a variety of experimental methods are conceivable.
hep-ph/0211109
Wayne W. Repko
Duane A. Dicus and Wayne W. Repko
Discriminating between models for the dark energy
Additional references, expanded discussion of entropy including a new figure
Phys.Rev. D67 (2003) 083520
10.1103/PhysRevD.67.083520
null
hep-ph astro-ph
null
Recent measurements suggest our universe has a substantial dark energy component, which is usually interpreted in terms of a cosmological constant. Here we examine how much the form of this dark energy can be modified while still retaining an acceptable fit to the high redshift supernova data. We first consider changes in the dark energy equation of state and then explore a model in which the dark energy is interpreted as a fluid with a bulk viscosity.
[ { "created": "Thu, 7 Nov 2002 20:11:42 GMT", "version": "v1" }, { "created": "Sun, 8 Dec 2002 18:40:26 GMT", "version": "v2" }, { "created": "Sun, 2 Feb 2003 18:40:04 GMT", "version": "v3" } ]
2009-11-07
[ [ "Dicus", "Duane A.", "" ], [ "Repko", "Wayne W.", "" ] ]
Recent measurements suggest our universe has a substantial dark energy component, which is usually interpreted in terms of a cosmological constant. Here we examine how much the form of this dark energy can be modified while still retaining an acceptable fit to the high redshift supernova data. We first consider changes in the dark energy equation of state and then explore a model in which the dark energy is interpreted as a fluid with a bulk viscosity.
0712.1779
Nikolaos Mavromatos
J. Alexandre, K. Farakos, N. E. Mavromatos and P. Pasipoularides
Neutrino oscillations in a stochastic model for space-time foam
12 pages RevTex4, no figures
Phys.Rev.D77:105001,2008
10.1103/PhysRevD.77.105001
null
hep-ph astro-ph hep-th
null
We study decoherence models for flavour oscillations in four-dimensional stochastically fluctuating space times and discuss briefly the sensitivity of current neutrino experiments to such models. We pay emphasis on demonstrating the model dependence of the associated decoherence-induced damping coefficients in front of the oscillatory terms in the respective transition probabilities between flavours. Within the context of specific models of foam, involving point-like D-branes and leading to decoherence-induced damping which is inversely proportional to the neutrino energies, we also argue that future limits on the relevant decoherence parameters coming from TeV astrophysical neutrinos, to be observed in ICE-CUBE, are not far from theoretically expected values with Planck mass suppression. Ultra high energy neutrinos from Gamma Ray Bursts at cosmological distances can also exhibit in principle sensitivity to such effects.
[ { "created": "Tue, 11 Dec 2007 17:40:42 GMT", "version": "v1" } ]
2008-11-26
[ [ "Alexandre", "J.", "" ], [ "Farakos", "K.", "" ], [ "Mavromatos", "N. E.", "" ], [ "Pasipoularides", "P.", "" ] ]
We study decoherence models for flavour oscillations in four-dimensional stochastically fluctuating space times and discuss briefly the sensitivity of current neutrino experiments to such models. We pay emphasis on demonstrating the model dependence of the associated decoherence-induced damping coefficients in front of the oscillatory terms in the respective transition probabilities between flavours. Within the context of specific models of foam, involving point-like D-branes and leading to decoherence-induced damping which is inversely proportional to the neutrino energies, we also argue that future limits on the relevant decoherence parameters coming from TeV astrophysical neutrinos, to be observed in ICE-CUBE, are not far from theoretically expected values with Planck mass suppression. Ultra high energy neutrinos from Gamma Ray Bursts at cosmological distances can also exhibit in principle sensitivity to such effects.
2308.14032
Hai-Bing Fu
Tao Zhong, Ya-Hong Dai, Hai-Bing Fu
$\rho$-meson longitudinal leading-twist distribution amplitude revisited and the $D\to \rho$ semileptonic decay
9 pages, 3 figures
null
null
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
Motivated by our previous work [Phys. Rev. D \textbf{104}, no.1, 016021 (2021)] on pionic leading-twist distribution amplitude (DA), we revisit $\rho$-meson leading-twist longitudinal DA $\phi_{2;\rho}^\|(x,\mu)$ in this paper. A model proposed by Chang based on the Dyson-Schwinger equations (DSEs) is adopted to describe the behavior of $\phi_{2;\rho}^\|(x,\mu)$. On the other hand, the $\xi$-moments of $\phi_{2;\rho}^\|(x,\mu)$ are calculated with the QCD sum rules in the framework of the background field theory. The sum rule formula for those moments are improved. More accurate values for the first five nonzero $\xi$-moments at typical scale $\mu =1, 1.4, 2, 3~{\rm GeV}$ are given, e.g., at $\mu = 1~{\rm GeV}$, \modi{$\langle\xi^2\rangle_{2;\rho}^\| = 0.220(6) $, $\langle\xi^4\rangle_{2;\rho}^\| = 0.103(4)$, $\langle\xi^6\rangle_{2;\rho}^\| = 0.066(5)$, $\langle\xi^8\rangle_{2;\rho}^\| = 0.046(4)$ and $\langle\xi^{10}\rangle_{2;\rho}^\| = 0.035(3)$}. By fitting those values with the least squares method, the DSE model for $\phi_{2;\rho}^\|(x,\mu)$ is determined. By taking the left-handed current light-cone sum rule approach, we get the transition form factor at large recoil region, {\it i.e.} $A_1(0) = 0.498^{+0.014}_{-0.012}$, $A_2(0)=0.460^{+0.055}_{-0.047}$, $V(0) = 0.800^{+0.015}_{-0.014}$, and the ratio $r_2 = 0.923^{+0.133}_{-0.119}$, $r_V = 1.607^{+0.071}_{-0.071}$. After making the extrapolation with a rapidly converging series based on $z(t)$-expansion, we present the decay width for the semileptonic decays $D\to\rho\ell^+\nu_\ell$. Finally, the branching fractions are $\mathcal{B}(D^0\to \rho^- e^+ \nu_e) = 1.889^{+0.176}_{-0.170}\pm 0.005$, $\mathcal{B}(D^+ \to \rho^0 e^+ \nu_e) = 2.380^{+0.221}_{-0.214}\pm 0.012$, $\mathcal{B}(D^0\to \rho^- \mu^+ \nu_\mu) = 1.881^{+0.174}_{-0.168}\pm 0.005$, $\mathcal{B}(D^+ \to \rho^0 \mu^+ \nu_\mu) =2.369^{+0.219}_{-0.211}\pm 0.011$.
[ { "created": "Sun, 27 Aug 2023 07:49:53 GMT", "version": "v1" } ]
2023-08-29
[ [ "Zhong", "Tao", "" ], [ "Dai", "Ya-Hong", "" ], [ "Fu", "Hai-Bing", "" ] ]
Motivated by our previous work [Phys. Rev. D \textbf{104}, no.1, 016021 (2021)] on pionic leading-twist distribution amplitude (DA), we revisit $\rho$-meson leading-twist longitudinal DA $\phi_{2;\rho}^\|(x,\mu)$ in this paper. A model proposed by Chang based on the Dyson-Schwinger equations (DSEs) is adopted to describe the behavior of $\phi_{2;\rho}^\|(x,\mu)$. On the other hand, the $\xi$-moments of $\phi_{2;\rho}^\|(x,\mu)$ are calculated with the QCD sum rules in the framework of the background field theory. The sum rule formula for those moments are improved. More accurate values for the first five nonzero $\xi$-moments at typical scale $\mu =1, 1.4, 2, 3~{\rm GeV}$ are given, e.g., at $\mu = 1~{\rm GeV}$, \modi{$\langle\xi^2\rangle_{2;\rho}^\| = 0.220(6) $, $\langle\xi^4\rangle_{2;\rho}^\| = 0.103(4)$, $\langle\xi^6\rangle_{2;\rho}^\| = 0.066(5)$, $\langle\xi^8\rangle_{2;\rho}^\| = 0.046(4)$ and $\langle\xi^{10}\rangle_{2;\rho}^\| = 0.035(3)$}. By fitting those values with the least squares method, the DSE model for $\phi_{2;\rho}^\|(x,\mu)$ is determined. By taking the left-handed current light-cone sum rule approach, we get the transition form factor at large recoil region, {\it i.e.} $A_1(0) = 0.498^{+0.014}_{-0.012}$, $A_2(0)=0.460^{+0.055}_{-0.047}$, $V(0) = 0.800^{+0.015}_{-0.014}$, and the ratio $r_2 = 0.923^{+0.133}_{-0.119}$, $r_V = 1.607^{+0.071}_{-0.071}$. After making the extrapolation with a rapidly converging series based on $z(t)$-expansion, we present the decay width for the semileptonic decays $D\to\rho\ell^+\nu_\ell$. Finally, the branching fractions are $\mathcal{B}(D^0\to \rho^- e^+ \nu_e) = 1.889^{+0.176}_{-0.170}\pm 0.005$, $\mathcal{B}(D^+ \to \rho^0 e^+ \nu_e) = 2.380^{+0.221}_{-0.214}\pm 0.012$, $\mathcal{B}(D^0\to \rho^- \mu^+ \nu_\mu) = 1.881^{+0.174}_{-0.168}\pm 0.005$, $\mathcal{B}(D^+ \to \rho^0 \mu^+ \nu_\mu) =2.369^{+0.219}_{-0.211}\pm 0.011$.
1307.4068
Gregory Adkins
Gregory S. Adkins and Theodore J. Yoder
Lorentz and CPT violation in the hydrogen spectrum
Presented at the Sixth Meeting on CPT and Lorentz Symmetry, Bloomington, Indiana, June 17-21, 2013
null
10.1142/9789814566438_0022
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We have studied the effect of hypothetical violations of Lorentz and CPT symmetry by calculating the corrections to the energy levels of hydrogen induced by the Standard-Model Extension (SME). Hydrogen studies are interesting because the energy levels of hydrogen can be measured with great precision and the theory for hydrogen based on the Standard Model (SM) is well understood. We obtained corrections through order \alpha^2 times the SME parameters for all levels of hydrogen and applied them to determine the SME corrections to the transition frequency for the 2S-1S transition.
[ { "created": "Mon, 15 Jul 2013 19:44:39 GMT", "version": "v1" } ]
2017-08-23
[ [ "Adkins", "Gregory S.", "" ], [ "Yoder", "Theodore J.", "" ] ]
We have studied the effect of hypothetical violations of Lorentz and CPT symmetry by calculating the corrections to the energy levels of hydrogen induced by the Standard-Model Extension (SME). Hydrogen studies are interesting because the energy levels of hydrogen can be measured with great precision and the theory for hydrogen based on the Standard Model (SM) is well understood. We obtained corrections through order \alpha^2 times the SME parameters for all levels of hydrogen and applied them to determine the SME corrections to the transition frequency for the 2S-1S transition.
1505.06799
Kouji Kashiwa
Kouji Kashiwa, Akira Ohnishi
Topological feature and phase structure of QCD at complex chemical potential
6 pages, 2 figures
Phys.Lett.B750:282-286,2015
10.1016/j.physletb.2015.09.036
YITP-15-45
hep-ph hep-lat hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The pseudo-critical temperature of the confinement-deconfinement transition and the phase transition surface are investigated by using the complex chemical potential. We can interpret the imaginary chemical potential as the Aharonov-Bohm phase, then the analogy of the topological order suggests that the Roberge-Weiss endpoint would define the pseudo-critical temperature. The behavior of the Roberge-Weiss endpoint at small real quark chemical potential is investigated with the perturbative expansion. The expected QCD phase diagram at complex chemical potential is presented.
[ { "created": "Tue, 26 May 2015 03:49:31 GMT", "version": "v1" }, { "created": "Tue, 6 Oct 2015 05:30:55 GMT", "version": "v2" } ]
2015-10-07
[ [ "Kashiwa", "Kouji", "" ], [ "Ohnishi", "Akira", "" ] ]
The pseudo-critical temperature of the confinement-deconfinement transition and the phase transition surface are investigated by using the complex chemical potential. We can interpret the imaginary chemical potential as the Aharonov-Bohm phase, then the analogy of the topological order suggests that the Roberge-Weiss endpoint would define the pseudo-critical temperature. The behavior of the Roberge-Weiss endpoint at small real quark chemical potential is investigated with the perturbative expansion. The expected QCD phase diagram at complex chemical potential is presented.
1702.05738
Muhammad Goharipour
Muhammad Goharipour and Hossein Mehraban
Study of isolated prompt photon production in $ p $-Pb collisions for the ALICE kinematics
12 pages, 10 figures
Phys.Rev. D95 (2017) 054002
10.1103/PhysRevD.95.054002
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Prompt photon production is known as a powerful tool for testing perturbative QCD predictions and also the validity of parton densities in the nucleon and nuclei especially of the gluon. In this work, we have performed a detailed study on this subject focusing on the isolated prompt photon production in $ p $-Pb collisions at forward rapidity at the LHC. The impact of input nuclear modifications obtained from different global analyses by various groups on several quantities has been investigated to estimate the order of magnitude of the difference between their predictions. We have also studied in detail the theoretical uncertainties in the results due to various sources. We found that there is a remarkable difference between the predictions from the nCTEQ15 and other groups in all ranges of photon transverse momentum $ p_\textrm{T}^\gamma $. Their differences become more explicit in the calculation of the nuclear modification ratio and also the yield asymmetry between the forward and backward rapidities rather than single differential cross sections. We emphasize that future measurements with ALICE will be very useful not only for decreasing the uncertainty of the gluon nuclear modification, but also to accurately determine its central values, especially in the shadowing region.
[ { "created": "Sun, 19 Feb 2017 11:01:20 GMT", "version": "v1" }, { "created": "Sun, 5 Mar 2017 22:05:13 GMT", "version": "v2" } ]
2017-03-07
[ [ "Goharipour", "Muhammad", "" ], [ "Mehraban", "Hossein", "" ] ]
Prompt photon production is known as a powerful tool for testing perturbative QCD predictions and also the validity of parton densities in the nucleon and nuclei especially of the gluon. In this work, we have performed a detailed study on this subject focusing on the isolated prompt photon production in $ p $-Pb collisions at forward rapidity at the LHC. The impact of input nuclear modifications obtained from different global analyses by various groups on several quantities has been investigated to estimate the order of magnitude of the difference between their predictions. We have also studied in detail the theoretical uncertainties in the results due to various sources. We found that there is a remarkable difference between the predictions from the nCTEQ15 and other groups in all ranges of photon transverse momentum $ p_\textrm{T}^\gamma $. Their differences become more explicit in the calculation of the nuclear modification ratio and also the yield asymmetry between the forward and backward rapidities rather than single differential cross sections. We emphasize that future measurements with ALICE will be very useful not only for decreasing the uncertainty of the gluon nuclear modification, but also to accurately determine its central values, especially in the shadowing region.
2404.13438
Zahra Rezaei
Zahra Rezaei and Aboozar Ghaffary
Impact of Noncommutative Spacetime on Anomalous Magnetic Moment of Muon
6 pages, 2 figures
null
null
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
The Standard Model is a theory that accurately predicts the interactions of fundamental particles. However, in recent years, certain phenomena have arisen that cannot be explained by this theory. One particular challenge is the anomalous magnetic moment of the muon. Various theories have been proposed in the Beyond Standard Model, with the aim of addressing these anomalies. One such theory is the Noncommutative Space-Time, which places importance on the noncommutative parameter ($\theta ^{\mu \nu}$). Different values for this parameter have been explored in various articles. However, in this particular article, we utilize the most precise values of $ (240 \, TeV)^{-2}$ for muons and $(3000 \, TeV)^{-2}$ for electrons, in order to align our findings more closely with reality. The tree level diagram for the muon in the Seiberg-Witten map has not yet been calculated. However, we have performed this calculation and predict the anomalous magnetic moment of the muon to be approximately $10^{-10}$. The Noncommutative Space-Time theory yields accurate results in both high energy and low energy physics. Furthermore, the predicted electric dipole moment for the muon and electron, using the parameters outlined in this study are about $10^{-24}$ e.cm for the muon and $10^{-34}$ e.cm for the electron.
[ { "created": "Sat, 20 Apr 2024 18:07:46 GMT", "version": "v1" } ]
2024-04-23
[ [ "Rezaei", "Zahra", "" ], [ "Ghaffary", "Aboozar", "" ] ]
The Standard Model is a theory that accurately predicts the interactions of fundamental particles. However, in recent years, certain phenomena have arisen that cannot be explained by this theory. One particular challenge is the anomalous magnetic moment of the muon. Various theories have been proposed in the Beyond Standard Model, with the aim of addressing these anomalies. One such theory is the Noncommutative Space-Time, which places importance on the noncommutative parameter ($\theta ^{\mu \nu}$). Different values for this parameter have been explored in various articles. However, in this particular article, we utilize the most precise values of $ (240 \, TeV)^{-2}$ for muons and $(3000 \, TeV)^{-2}$ for electrons, in order to align our findings more closely with reality. The tree level diagram for the muon in the Seiberg-Witten map has not yet been calculated. However, we have performed this calculation and predict the anomalous magnetic moment of the muon to be approximately $10^{-10}$. The Noncommutative Space-Time theory yields accurate results in both high energy and low energy physics. Furthermore, the predicted electric dipole moment for the muon and electron, using the parameters outlined in this study are about $10^{-24}$ e.cm for the muon and $10^{-34}$ e.cm for the electron.
hep-ph/9812327
Pierre Sikivie
S. Chang, C. Hagmann and P. Sikivie
The cold axion populations
28 pages, 12 figures, invited talk at the Dark98 Conference, Heidelberg, Germany, July 20-25, 1998
null
null
UFIFT-HEP-98-37
hep-ph
null
We give a systematic discussion of the contributions to the cosmological energy density in axions from vacuum realignment, string decay and wall decay. We call these the cold axion populations because their kinetic energy per particle is at all times much less than the ambient temperature. In case there is no inflation after the Peccei-Quinn phase transition, the value of the axion mass for which axions contribute the critical energy density for closure is estimated to be of order $6 \cdot 10^{-6}$ eV, with large uncertainties. It is emphasized that there are two groups of cold axions differing in velocity dispersion by a factor of order $10^3$.
[ { "created": "Thu, 10 Dec 1998 20:34:38 GMT", "version": "v1" } ]
2007-05-23
[ [ "Chang", "S.", "" ], [ "Hagmann", "C.", "" ], [ "Sikivie", "P.", "" ] ]
We give a systematic discussion of the contributions to the cosmological energy density in axions from vacuum realignment, string decay and wall decay. We call these the cold axion populations because their kinetic energy per particle is at all times much less than the ambient temperature. In case there is no inflation after the Peccei-Quinn phase transition, the value of the axion mass for which axions contribute the critical energy density for closure is estimated to be of order $6 \cdot 10^{-6}$ eV, with large uncertainties. It is emphasized that there are two groups of cold axions differing in velocity dispersion by a factor of order $10^3$.
hep-ph/9304205
Maggie Best
Alexei Yu. Smirnov
See-saw Enhancement of Lepton Mixing
16 pages, plain TeX document, Institute for Advanced Study number AST 93/14
Phys.Rev. D48 (1993) 3264-3270
10.1103/PhysRevD.48.3264
null
hep-ph
null
The see-saw mechanism of neutrino mass generation may enhance lepton mixing up to maximal even if the Dirac mass matrices of leptons have structure similar to that in the quark sector. Two sets of conditions for such an enhancement are found. The first one includes the see-saw generation of heavy Majorana masses for right-handed neutrinos and a universality of Yukawa couplings which can follow from the unification of neutrinos with new superheavy neutral leptons. The second set is related to lepton number symmetry of the Yukawa interactions in the Dirac basis of neutrinos. Models which realize these conditions have strong hierarchy or strong degeneration of Majorana masses of the right-handed neutrinos.
[ { "created": "Fri, 2 Apr 1993 18:49:08 GMT", "version": "v1" } ]
2009-10-22
[ [ "Smirnov", "Alexei Yu.", "" ] ]
The see-saw mechanism of neutrino mass generation may enhance lepton mixing up to maximal even if the Dirac mass matrices of leptons have structure similar to that in the quark sector. Two sets of conditions for such an enhancement are found. The first one includes the see-saw generation of heavy Majorana masses for right-handed neutrinos and a universality of Yukawa couplings which can follow from the unification of neutrinos with new superheavy neutral leptons. The second set is related to lepton number symmetry of the Yukawa interactions in the Dirac basis of neutrinos. Models which realize these conditions have strong hierarchy or strong degeneration of Majorana masses of the right-handed neutrinos.
hep-ph/0409008
Howard E. Haber
Howard E. Haber
Higgs Theory--A Brief Overview
5 pages (plus cover page), invited talk at the International Conference on Linear Colliders LCWS-04, 19--23 April 2004, Paris, France
null
null
SCIPP 04/13
hep-ph
null
A brief overview is given of the theory of Higgs bosons and electroweak symmetry breaking that is relevant for the Higgs physics program at the Linear Collider.
[ { "created": "Wed, 1 Sep 2004 12:16:52 GMT", "version": "v1" } ]
2007-05-23
[ [ "Haber", "Howard E.", "" ] ]
A brief overview is given of the theory of Higgs bosons and electroweak symmetry breaking that is relevant for the Higgs physics program at the Linear Collider.
1806.07238
Evgeny Zhemchugov
Mikhail Vysotsky, Evgeny Zhemchugov
Equivalent photons in proton-proton and ion-ion collisions at the LHC
15 p., 7 figs, 4 tables. Appendix C is added where the photon spectrum dependence on the impact parameter is considered and the survival factor that takes into account overlap of the colliding particles in the transverse direction is defined
null
10.3367/UFNe.2018.07.038389
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Equivalent photon approximation is used to calculate fiducial cross sections for dimuon production in ultraperipheral proton-proton and lead-lead collisions. Analytical formulae taking into account experimental cuts are derived. The results are compared with the measurements reported by the ATLAS collaboration.
[ { "created": "Tue, 19 Jun 2018 13:57:05 GMT", "version": "v1" }, { "created": "Thu, 2 Aug 2018 09:41:23 GMT", "version": "v2" }, { "created": "Thu, 11 Oct 2018 12:52:46 GMT", "version": "v3" }, { "created": "Mon, 11 Feb 2019 14:16:25 GMT", "version": "v4" }, { "created": "Mon, 12 Aug 2019 14:17:24 GMT", "version": "v5" } ]
2019-08-13
[ [ "Vysotsky", "Mikhail", "" ], [ "Zhemchugov", "Evgeny", "" ] ]
Equivalent photon approximation is used to calculate fiducial cross sections for dimuon production in ultraperipheral proton-proton and lead-lead collisions. Analytical formulae taking into account experimental cuts are derived. The results are compared with the measurements reported by the ATLAS collaboration.
hep-ph/9510238
Andre Likhoded
A.V.Berezhnoy, V.V.Kiselev, A.K.Likhoded
Photonic production of P-wave states of B_c mesons
7 pages, REVTEX file, 6 figures (uuencoded compressed tar-file)
Phys.Lett.B381:341-347,1996; Phys.Atom.Nucl.59:1959-1966,1996; Yad.Fiz.59N11:2032-2040,1996
10.1016/0370-2693(96)00562-X
IHEP 95-119, Protvino
hep-ph
null
Numerical calculations for the production of $P$-wave levels of $B_c$ quarkonium in $\gamma\gamma$ collisions are performed in the leading $O(\alpha_s^2\alpha_{em}^2)$ order of perturbation theory. The total cross-section of $P$-wave state production is about 10 \% of that for the $S$-wave levels. The contribution of fragmentation component ($6+6$ diagrams) is low, and the basic contribution is determined by the recombination mechanism ($8$ Feynman diagrams). The gauge invariant term of the $\bar b\to B_c$ fragmentation ($6$ diagrams) quite accurately reproduces the result of the fragmentation model, whereas there is a strong deviation of the $c\to B_c$ fragmentation term from the predictions of the fragmentation model.
[ { "created": "Fri, 6 Oct 1995 11:32:12 GMT", "version": "v1" } ]
2011-01-27
[ [ "Berezhnoy", "A. V.", "" ], [ "Kiselev", "V. V.", "" ], [ "Likhoded", "A. K.", "" ] ]
Numerical calculations for the production of $P$-wave levels of $B_c$ quarkonium in $\gamma\gamma$ collisions are performed in the leading $O(\alpha_s^2\alpha_{em}^2)$ order of perturbation theory. The total cross-section of $P$-wave state production is about 10 \% of that for the $S$-wave levels. The contribution of fragmentation component ($6+6$ diagrams) is low, and the basic contribution is determined by the recombination mechanism ($8$ Feynman diagrams). The gauge invariant term of the $\bar b\to B_c$ fragmentation ($6$ diagrams) quite accurately reproduces the result of the fragmentation model, whereas there is a strong deviation of the $c\to B_c$ fragmentation term from the predictions of the fragmentation model.
hep-ph/0209217
Toshifumi Yamashita
Nobuhiro Maekawa and Toshifumi Yamashita
Gauge Coupling Unification in GUT with Anomalous U(1) Symmetry
4 pages, RevTeX, to appear in Phys.Rev.Lett
Phys.Rev.Lett. 90 (2003) 121801
10.1103/PhysRevLett.90.121801
KUNS-1804
hep-ph
null
We show that in the framework of grand unified theory (GUT) with anomalous $U(1)_A$ gauge symmetry, the success of the gauge coupling unification in the minimal SU(5) GUT is naturally explained, even if the mass spectrum of superheavy fields does not respect SU(5) symmetry. Because the unification scale for most realizations of the theory becomes smaller than the usual GUT scale, it suggests that the present level of experiments is close to that sufficient to observe proton decay via dimension 6 operators, $p\to e+\pi$.
[ { "created": "Thu, 19 Sep 2002 10:09:21 GMT", "version": "v1" }, { "created": "Wed, 5 Feb 2003 10:08:30 GMT", "version": "v2" } ]
2009-11-07
[ [ "Maekawa", "Nobuhiro", "" ], [ "Yamashita", "Toshifumi", "" ] ]
We show that in the framework of grand unified theory (GUT) with anomalous $U(1)_A$ gauge symmetry, the success of the gauge coupling unification in the minimal SU(5) GUT is naturally explained, even if the mass spectrum of superheavy fields does not respect SU(5) symmetry. Because the unification scale for most realizations of the theory becomes smaller than the usual GUT scale, it suggests that the present level of experiments is close to that sufficient to observe proton decay via dimension 6 operators, $p\to e+\pi$.
hep-ph/0010010
K. Sridhar
Smaragda Lola, Prakash Mathews, Sreerup Raychaudhuri and K. Sridhar
Extra Dimensions: A View from the Top
Typos corrected, references added. 12 pages, LaTeX, 2 ps figures
null
10.1103/PhysRevE.83.036603
CERN-TH/2000-275, IFT-P082/2000, IITK-PHY/2000/20, TIFR/TH/00-54
hep-ph
null
In models with compact extra dimensions, where the Standard Model fields are confined to a 3+1 dimensional hyperplane, the $t \bar t$ production cross-section at a hadron collider can receive significant contributions from multiple exchange of KK modes of the graviton. These are carefully computed in the well-known ADD and RS scenarios, taking the energy dependence of the sum over graviton propagators into account. Using data from Run-I of the Tevatron, 95% C.L. bounds on the parameter space of both models are derived. For Run-II of the Tevatron and LHC, discovery limits are estimated.
[ { "created": "Mon, 2 Oct 2000 11:46:32 GMT", "version": "v1" }, { "created": "Wed, 18 Oct 2000 14:25:22 GMT", "version": "v2" } ]
2015-06-25
[ [ "Lola", "Smaragda", "" ], [ "Mathews", "Prakash", "" ], [ "Raychaudhuri", "Sreerup", "" ], [ "Sridhar", "K.", "" ] ]
In models with compact extra dimensions, where the Standard Model fields are confined to a 3+1 dimensional hyperplane, the $t \bar t$ production cross-section at a hadron collider can receive significant contributions from multiple exchange of KK modes of the graviton. These are carefully computed in the well-known ADD and RS scenarios, taking the energy dependence of the sum over graviton propagators into account. Using data from Run-I of the Tevatron, 95% C.L. bounds on the parameter space of both models are derived. For Run-II of the Tevatron and LHC, discovery limits are estimated.
1205.4915
Keiko Nagao
Keiko I. Nagao and Tatsuhiro Naka
Directional Search for Isospin-Violating Dark Matter with Nuclear Emulsion
Prepared for the proceedings of the International Workshop on Grand Unified Theories (GUT2012) held at Yukawa Institute for Theoretical Physics, Kyoto, Japan, March 2012
null
10.1063/1.4742116
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Some of direct dark matter searches reported not only positive signals but also annual modulation of the signal event. However, the parameter spaces have been excluded by other experiments. Isospin violating dark matter solves the contradiction by supposing different coupling to proton and neutron. We study the possibility to test the favored parameter region by isospin violating dark matter model with the future detector of dark matter using the nuclear emulsion. Since the nuclear emulsion detector has directional sensitivity, the detector is expected to examine whether the annual modulations observed other experiments is caused by dark matter or background signals.
[ { "created": "Tue, 22 May 2012 13:39:25 GMT", "version": "v1" } ]
2015-06-05
[ [ "Nagao", "Keiko I.", "" ], [ "Naka", "Tatsuhiro", "" ] ]
Some of direct dark matter searches reported not only positive signals but also annual modulation of the signal event. However, the parameter spaces have been excluded by other experiments. Isospin violating dark matter solves the contradiction by supposing different coupling to proton and neutron. We study the possibility to test the favored parameter region by isospin violating dark matter model with the future detector of dark matter using the nuclear emulsion. Since the nuclear emulsion detector has directional sensitivity, the detector is expected to examine whether the annual modulations observed other experiments is caused by dark matter or background signals.
0804.2204
Yuming Wang
Yu-Ming Wang, M. Jamil Aslam, Cai-Dian Lu
Scalar mesons in weak semileptonic decays of $B_{(s)}$
20 pages, 4 figures
Phys.Rev.D78:014006,2008
10.1103/PhysRevD.78.014006
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The transition form factors of $B_{(s)} \to S$, with $S$ denoting a scalar meson, are investigated in the light-cone sum rules approach. The numerical values are approximately twice as large as that estimated in the light-front quark model and QCD sum rules approach. Using these form factors, we present the analysis of the decay rates for $B \to a_0(1450) l \bar{\nu}_l $, $B \to K^{\ast}_0(1430) l \bar{l}$, $B_s \to K^{\ast}_0(1430) l \bar{\nu}_l$ and $B_s \to f_0(1500) l \bar{l}$ with $l=e, \mu, \tau$. The results indicate that magnitudes of $BR(\bar{B}_0 \to a_0(1450) l \bar{\nu}_l)$ and $BR(B_s \to K^{\ast}_0(1430) l \bar{\nu}_l)$ can arrive at the order of $10^{-4}$, which can be measured in the future experiments to clarify the inner structure of scalar mesons. It is also observed that $BR(B \to K^{\ast}_0(1430) \tau^+ \tau^-)$ and $BR(B_s \to f_0(1500) \tau^+ \tau^-)$ are an order of magnitude smaller than the corresponding channels of $e^+ e^-$ and $\mu^+ \mu^-$ final states due to the heavily suppressed phase space . Moreover, the longitudinal lepton polarization asymmetry for $B \to K^{\ast}_0(1430) l \bar{l}$ and $B_s \to f_0(1500) l \bar{l}$ are also investigated, whose values are close to -1 for the $e^+ e^-$ and $\mu^+ \mu^-$ pair except the region close to the end points.
[ { "created": "Mon, 14 Apr 2008 15:39:39 GMT", "version": "v1" } ]
2008-11-26
[ [ "Wang", "Yu-Ming", "" ], [ "Aslam", "M. Jamil", "" ], [ "Lu", "Cai-Dian", "" ] ]
The transition form factors of $B_{(s)} \to S$, with $S$ denoting a scalar meson, are investigated in the light-cone sum rules approach. The numerical values are approximately twice as large as that estimated in the light-front quark model and QCD sum rules approach. Using these form factors, we present the analysis of the decay rates for $B \to a_0(1450) l \bar{\nu}_l $, $B \to K^{\ast}_0(1430) l \bar{l}$, $B_s \to K^{\ast}_0(1430) l \bar{\nu}_l$ and $B_s \to f_0(1500) l \bar{l}$ with $l=e, \mu, \tau$. The results indicate that magnitudes of $BR(\bar{B}_0 \to a_0(1450) l \bar{\nu}_l)$ and $BR(B_s \to K^{\ast}_0(1430) l \bar{\nu}_l)$ can arrive at the order of $10^{-4}$, which can be measured in the future experiments to clarify the inner structure of scalar mesons. It is also observed that $BR(B \to K^{\ast}_0(1430) \tau^+ \tau^-)$ and $BR(B_s \to f_0(1500) \tau^+ \tau^-)$ are an order of magnitude smaller than the corresponding channels of $e^+ e^-$ and $\mu^+ \mu^-$ final states due to the heavily suppressed phase space . Moreover, the longitudinal lepton polarization asymmetry for $B \to K^{\ast}_0(1430) l \bar{l}$ and $B_s \to f_0(1500) l \bar{l}$ are also investigated, whose values are close to -1 for the $e^+ e^-$ and $\mu^+ \mu^-$ pair except the region close to the end points.
hep-ph/9912384
Shlepin Yura
E. V. Bugaev, B. V. Mangazeev, Y. V. Shlepin
QCD-oriented nondiagonal GVDM
12 p
null
null
null
hep-ph
null
The nondiagonal generalized vector dominance model (GVDM) of photoabsorption is elaborated using QCD-motivated picture of the (gamma)-(q,anti q) - transition and subsequent meson dominated scattering of the (q, anti q)-pair on the nucleon. The relativistic constituent quark model for a description of the meson (q, anti q)-wave functionsis used. The meson-nucleon scattering is calculated in the two-gluon exchange approximation. It is shown that the destructive interference effects and corresponding cancellations in the photoabsorption cross section formula are small, so the GVDM predictions are incorrect if no extra cut-off factors in GVDM formulas are introduced.
[ { "created": "Thu, 16 Dec 1999 18:28:05 GMT", "version": "v1" } ]
2009-09-25
[ [ "Bugaev", "E. V.", "" ], [ "Mangazeev", "B. V.", "" ], [ "Shlepin", "Y. V.", "" ] ]
The nondiagonal generalized vector dominance model (GVDM) of photoabsorption is elaborated using QCD-motivated picture of the (gamma)-(q,anti q) - transition and subsequent meson dominated scattering of the (q, anti q)-pair on the nucleon. The relativistic constituent quark model for a description of the meson (q, anti q)-wave functionsis used. The meson-nucleon scattering is calculated in the two-gluon exchange approximation. It is shown that the destructive interference effects and corresponding cancellations in the photoabsorption cross section formula are small, so the GVDM predictions are incorrect if no extra cut-off factors in GVDM formulas are introduced.
hep-ph/9610481
null
P. Binetruy, S. Lavignac, S. Petcov and P. Ramond
Quasi-degenerate neutrinos from an abelian family symmetry
24 pages, latex
Nucl.Phys. B496 (1997) 3-23
10.1016/S0550-3213(97)00211-3
null
hep-ph
null
We show that models with an abelian family symmetry which accounts for the observed hierarchies of masses and mixings in the quark sector may also accomodate quasi-degeneracies in the neutrino mass spectrum. Such approximate degeneracies are, in this context, associated with large mixing angles. The parameters of this class of models are constrained. We discuss their phenomenological implications for present and foreseen neutrino experiments.
[ { "created": "Fri, 25 Oct 1996 06:13:33 GMT", "version": "v1" } ]
2009-10-30
[ [ "Binetruy", "P.", "" ], [ "Lavignac", "S.", "" ], [ "Petcov", "S.", "" ], [ "Ramond", "P.", "" ] ]
We show that models with an abelian family symmetry which accounts for the observed hierarchies of masses and mixings in the quark sector may also accomodate quasi-degeneracies in the neutrino mass spectrum. Such approximate degeneracies are, in this context, associated with large mixing angles. The parameters of this class of models are constrained. We discuss their phenomenological implications for present and foreseen neutrino experiments.
hep-ph/0204207
Daniel Boer
Daniel Boer, Jan-Willem van Holten
Exploring the QED vacuum with laser interferometers
4 pages, no figures, revtex, uses slashbox.sty
null
null
NIKHEF/2002-001
hep-ph
null
It is demonstrated that the nonlinear, and as yet unobserved, QED effect of slowing down light by application of a strong magnetic field may be observable with large laser interferometers like for instance LIGO or GEO600.
[ { "created": "Wed, 17 Apr 2002 16:18:41 GMT", "version": "v1" } ]
2007-05-23
[ [ "Boer", "Daniel", "" ], [ "van Holten", "Jan-Willem", "" ] ]
It is demonstrated that the nonlinear, and as yet unobserved, QED effect of slowing down light by application of a strong magnetic field may be observable with large laser interferometers like for instance LIGO or GEO600.
1208.2316
Taro Kunimitsu
Taro Kunimitsu, Jun'ichi Yokoyama
Higgs condensation as an unwanted curvaton
13 pages; v2, layout adjusted, references added
Phys. Rev. D 86, 083541 (2012)
10.1103/PhysRevD.86.083541
RESCEU-40/12
hep-ph astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
During inflation in the early universe, the Higgs field continuously acquires long-wave quantum fluctuations. They accumulate to yield a non-vanishing value with an exponentially large correlation length. We study consequences of such Higgs condensations to show that, in inflation models where the universe is reheated through gravitational particle production at the transition to the kination regime, they not only contribute to reheat the universe but also act as a curvaton. Unfortunately, however, for parameters of the Standard Model Higgs field, this curvaton produces density fluctuations too large, so the inflation models followed by a long kination regime are ruled out.
[ { "created": "Sat, 11 Aug 2012 07:11:53 GMT", "version": "v1" }, { "created": "Thu, 30 Aug 2012 13:27:47 GMT", "version": "v2" } ]
2012-10-30
[ [ "Kunimitsu", "Taro", "" ], [ "Yokoyama", "Jun'ichi", "" ] ]
During inflation in the early universe, the Higgs field continuously acquires long-wave quantum fluctuations. They accumulate to yield a non-vanishing value with an exponentially large correlation length. We study consequences of such Higgs condensations to show that, in inflation models where the universe is reheated through gravitational particle production at the transition to the kination regime, they not only contribute to reheat the universe but also act as a curvaton. Unfortunately, however, for parameters of the Standard Model Higgs field, this curvaton produces density fluctuations too large, so the inflation models followed by a long kination regime are ruled out.
1406.2878
Heikki M\"antysaari
T. Lappi, H. M\"antysaari
Dipole amplitude with uncertainty estimate from HERA data and applications in Color Glass Condensate phenomenology
6 pages, 4 figures. Talk given by H.M. at XXII. International Workshop on Deep-Inelastic Scattering and Related Subjects
PoS (DIS2014) 068
null
null
hep-ph nucl-th
http://creativecommons.org/licenses/by-nc-sa/3.0/
We determine the initial condition for the small-$x$ evolution equation (BK) from the HERA deep inelastic scattering data using a new parametrization that also keeps the unintegrated gluon distribution positive. The obtained dipole amplitude and its uncertainty estimate can be used to compute single inclusive particle production in proton-proton and proton-nucleus collisions. We argue that one has to use consistently the proton transverse area measured in DIS and the total inelastic cross section when calculating the single inclusive cross section. This leads to a midrapidity nuclear modification factor $R_{pA}$ that approaches unity at large transverse momentum, independently of the center-of-mass energy.
[ { "created": "Wed, 11 Jun 2014 12:23:12 GMT", "version": "v1" } ]
2014-10-13
[ [ "Lappi", "T.", "" ], [ "Mäntysaari", "H.", "" ] ]
We determine the initial condition for the small-$x$ evolution equation (BK) from the HERA deep inelastic scattering data using a new parametrization that also keeps the unintegrated gluon distribution positive. The obtained dipole amplitude and its uncertainty estimate can be used to compute single inclusive particle production in proton-proton and proton-nucleus collisions. We argue that one has to use consistently the proton transverse area measured in DIS and the total inelastic cross section when calculating the single inclusive cross section. This leads to a midrapidity nuclear modification factor $R_{pA}$ that approaches unity at large transverse momentum, independently of the center-of-mass energy.
hep-ph/0509017
Kingman Cheung
Kingman Cheung, C.S. Kim, Jeonghyeon Song
Probing the radion-Higgs mixing at photon colliders
15 pages, including 2 tables, 5 figures
Phys.Rev.D72:115015,2005
10.1103/PhysRevD.72.115015
null
hep-ph
null
In the Randall-Sundrum model, the radion-Higgs mixing is weakly suppressed by the effective electroweak scale. A novel feature of the gravity-scalar mixing would be a sizable three-point vertex of $\grav$-$h$-$\phi$. We explore the potential of photon colliders, achieved by the laser backscattering technique, in probing the radion-Higgs mixing via the associated production of the radion with the Higgs boson. The advantage of photon colliders is the capability of adjusting the polarization of the incoming photons such that the signal of the spin-2 graviton exchange can be largely enhanced. The enhancement factor is shown to be about 5, except for small-$\xi$ region. We also study the corresponding backgrounds step-by-step in detail.
[ { "created": "Fri, 2 Sep 2005 09:48:06 GMT", "version": "v1" } ]
2008-11-26
[ [ "Cheung", "Kingman", "" ], [ "Kim", "C. S.", "" ], [ "Song", "Jeonghyeon", "" ] ]
In the Randall-Sundrum model, the radion-Higgs mixing is weakly suppressed by the effective electroweak scale. A novel feature of the gravity-scalar mixing would be a sizable three-point vertex of $\grav$-$h$-$\phi$. We explore the potential of photon colliders, achieved by the laser backscattering technique, in probing the radion-Higgs mixing via the associated production of the radion with the Higgs boson. The advantage of photon colliders is the capability of adjusting the polarization of the incoming photons such that the signal of the spin-2 graviton exchange can be largely enhanced. The enhancement factor is shown to be about 5, except for small-$\xi$ region. We also study the corresponding backgrounds step-by-step in detail.
1307.2464
Chong Sheng Li
Hai Tao Li, Chong Sheng Li, Ding Yu Shao, Li Lin Yang, Hua Xing Zhu
Top quark pair production at small transverse momentum in hadronic collisions
39 pages, 7 figures, 1 table; final version in PRD
Phys. Rev. D 88, 074004 (2013)
10.1103/PhysRevD.88.074004
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate the transverse momentum resummation for top quark pair production at hadron colliders using the soft-collinear effective theory and the heavy-quark effective theory. We derive the factorization formula for $t\bar{t}$ production at small pair transverse momentum, and show in detail the procedure for calculating the key ingredient of the factorization formula: the next-to-leading order soft functions. We compare our numerical results with experimental data and find that they are consistent within theoretical and experimental uncertainties. To verify the correctness of our resummation formula, we expand it to the next-to-leading order and the next-to-next-to-leading order, and compare those expressions with the exact fixed-order results numerically. Finally, using the results of transverse momentum resummation, we discuss the transverse-momentum-dependent forward-backward asymmetry at the Tevatron.
[ { "created": "Tue, 9 Jul 2013 14:08:51 GMT", "version": "v1" }, { "created": "Wed, 9 Oct 2013 15:09:12 GMT", "version": "v2" } ]
2013-10-30
[ [ "Li", "Hai Tao", "" ], [ "Li", "Chong Sheng", "" ], [ "Shao", "Ding Yu", "" ], [ "Yang", "Li Lin", "" ], [ "Zhu", "Hua Xing", "" ] ]
We investigate the transverse momentum resummation for top quark pair production at hadron colliders using the soft-collinear effective theory and the heavy-quark effective theory. We derive the factorization formula for $t\bar{t}$ production at small pair transverse momentum, and show in detail the procedure for calculating the key ingredient of the factorization formula: the next-to-leading order soft functions. We compare our numerical results with experimental data and find that they are consistent within theoretical and experimental uncertainties. To verify the correctness of our resummation formula, we expand it to the next-to-leading order and the next-to-next-to-leading order, and compare those expressions with the exact fixed-order results numerically. Finally, using the results of transverse momentum resummation, we discuss the transverse-momentum-dependent forward-backward asymmetry at the Tevatron.
2003.01723
Ma\'ira Dutra
Catarina Cosme, Ma\'ira Dutra, Teng Ma, Yongcheng Wu, Litao Yang
Neutrino Portal to FIMP Dark Matter with an Early Matter Era
39 pages, 11 figures, references added, typos corrected
J. High Energ. Phys. 2021, 26 (2021)
10.1007/JHEP03(2021)026
null
hep-ph astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the freeze-in production of Feebly Interacting Massive Particle (FIMP) dark matter candidates through a neutrino portal. We consider a hidden sector comprised of a fermion and a complex scalar, with the lightest one regarded as a FIMP candidate. We implement the Type-I Seesaw mechanism for generating the masses of the Standard Model (SM) neutrinos and consider three heavy neutrinos, responsible for mediating the interactions between the hidden and the SM sectors. We assume that an early matter-dominated era (EMDE) took place for some period between inflation and Big Bang Nucleosynthesis, making the Universe to expand faster than in the standard radiation-dominated era. In this case, the hidden and SM sectors are easily decoupled and larger couplings between FIMPs and SM particles are needed from the relic density constraints. In this context, we discuss the dynamics of dark matter throughout the modified cosmic history, evaluate the relevant constraints of the model and discuss the consequences of the duration of the EMDE for the dark matter production. Finally, we show that if the heavy neutrinos are not part of the thermal bath, this scenario becomes testable through indirect detection searches.
[ { "created": "Tue, 3 Mar 2020 19:00:00 GMT", "version": "v1" }, { "created": "Fri, 20 Mar 2020 18:49:56 GMT", "version": "v2" } ]
2021-03-11
[ [ "Cosme", "Catarina", "" ], [ "Dutra", "Maíra", "" ], [ "Ma", "Teng", "" ], [ "Wu", "Yongcheng", "" ], [ "Yang", "Litao", "" ] ]
We study the freeze-in production of Feebly Interacting Massive Particle (FIMP) dark matter candidates through a neutrino portal. We consider a hidden sector comprised of a fermion and a complex scalar, with the lightest one regarded as a FIMP candidate. We implement the Type-I Seesaw mechanism for generating the masses of the Standard Model (SM) neutrinos and consider three heavy neutrinos, responsible for mediating the interactions between the hidden and the SM sectors. We assume that an early matter-dominated era (EMDE) took place for some period between inflation and Big Bang Nucleosynthesis, making the Universe to expand faster than in the standard radiation-dominated era. In this case, the hidden and SM sectors are easily decoupled and larger couplings between FIMPs and SM particles are needed from the relic density constraints. In this context, we discuss the dynamics of dark matter throughout the modified cosmic history, evaluate the relevant constraints of the model and discuss the consequences of the duration of the EMDE for the dark matter production. Finally, we show that if the heavy neutrinos are not part of the thermal bath, this scenario becomes testable through indirect detection searches.
1401.2944
Emanuele Re
Emanuele Re
Reaching NNLOPS accuracy with POWHEG and MiNLO
6 pages, 2 figures. Submitted to the proceedings of the LC13 Workshop, September 16-20, 2013, ECT*, Trento, Italy
null
10.1393/ncc/i2014-11747-9
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We describe how a simulation of Higgs boson production accurate at next-to-next-to-leading order and matched to a parton shower can be built by combining the POWHEG and MiNLO methods and using HNNLO results as input.
[ { "created": "Mon, 13 Jan 2014 18:29:19 GMT", "version": "v1" } ]
2022-03-02
[ [ "Re", "Emanuele", "" ] ]
We describe how a simulation of Higgs boson production accurate at next-to-next-to-leading order and matched to a parton shower can be built by combining the POWHEG and MiNLO methods and using HNNLO results as input.
hep-ph/0111456
Ismd31
A.A. Savin (on behalf of the H1 and ZEUS collaborations)
Experimental Studies of Diffractive Processes at HERA
7 pages, 7 figure (6 in eps, 1 in ps) talk given at XXXI International Symposium on Multiparticle Dynamics, Sep. 1-7, 2001, Datong China URL http://ismd31.ccnu.edu.cn/
null
10.1142/9789812778048_0069
null
hep-ph
null
Diffractive processes in photon-proton interactions at HERA offer the opportunity to improve the understanding of the transition between the soft, non-perturbative regime in hadronic interactions at $Q^2 = 0$ and the perturbative region at high $Q^2$. Recent experimental results from HERA on inclusive diffractive scattering, exclusive vector meson production and the properties of the hadronic final state in diffraction are reviewed. The results are discussed in the context of current theoretical models.
[ { "created": "Fri, 30 Nov 2001 10:16:42 GMT", "version": "v1" } ]
2019-08-14
[ [ "Savin", "A. A.", "", "on behalf of the H1 and ZEUS collaborations" ] ]
Diffractive processes in photon-proton interactions at HERA offer the opportunity to improve the understanding of the transition between the soft, non-perturbative regime in hadronic interactions at $Q^2 = 0$ and the perturbative region at high $Q^2$. Recent experimental results from HERA on inclusive diffractive scattering, exclusive vector meson production and the properties of the hadronic final state in diffraction are reviewed. The results are discussed in the context of current theoretical models.
hep-ph/0306097
Patrick J. O'Donnell
Alakabha Datta and Patrick J. O'Donnell
A New State of Baryonium
7 pages
Phys.Lett.B567:273-276,2003
10.1016/j.physletb.2003.06.050
null
hep-ph hep-ex nucl-ex nucl-th
null
The recent discovery of a narrow resonance in the decay $J/\psi \to \gamma p \bar{p}$ is described as a zero baryon number, ``deuteron-like singlet ${}^1S_0 $'' state. The difference in binding energy of the deuteron (-2.225 MeV) and of the new state (-17.5 MeV) can be accounted for in a simple potential model with a $\lambda \cdot \lambda$ confining interaction.
[ { "created": "Wed, 11 Jun 2003 18:45:24 GMT", "version": "v1" } ]
2008-11-26
[ [ "Datta", "Alakabha", "" ], [ "O'Donnell", "Patrick J.", "" ] ]
The recent discovery of a narrow resonance in the decay $J/\psi \to \gamma p \bar{p}$ is described as a zero baryon number, ``deuteron-like singlet ${}^1S_0 $'' state. The difference in binding energy of the deuteron (-2.225 MeV) and of the new state (-17.5 MeV) can be accounted for in a simple potential model with a $\lambda \cdot \lambda$ confining interaction.
2308.10219
Kang Xian-Wei
Shuo-Ying Yu, Xian-Wei Kang
Nature of $X(3872)$ from its radiative decay
two columu, 8 pages, more clarifications and references added, accepted for publication in Phys. Letts. B
Phys. Lett. B 848 (2024) 138404
null
null
hep-ph hep-ex nucl-th
http://creativecommons.org/licenses/by/4.0/
We study the radiative decay of $X(3872)$ based on the assumption that $X(3872)$ is regarded as a $c\overline{c}$ charmonium with quantum number $J^{PC}=1^{++}$ ($J,\,P,\,C$ represent the spin, parity and charge conjugation, respectively). The form factors of $X(3872)$ transitions to $J/\psi\gamma$ and $\psi'\gamma$ ($\psi'$ denotes $\psi(2S)$ throughout the paper) are calculated in the framework of the covariant light-front quark model. The phenomenological wave function of a meson depends on the parameter $\beta$, whose inverse essentially describes the confinement scale. In the present work, the parameters $\beta$ for the vector $J/\psi$ and $\psi'$ mesons will be determined through their decay constants, which are obtained from the experimental values of their partial decay widths to the electron-positron pair. For $X(3872)$, we determined the value of $\beta$ by the decay width of $X(3872)\rightarrow \psi'\gamma$. Then, we examined the width of $X(3872)\to J/\psi\gamma$ in a manner of parameter-free prediction and compared it with the experimental value. As a result, an inconsistency or contradiction occurs between the widths of $X(3872)\to J/\psi\gamma$ and $X(3872)\to \psi'\gamma$. We thus conclude that $X(3872)$ cannot be a pure $c\overline c$ resonance and that other components are necessary in its wave function.
[ { "created": "Sun, 20 Aug 2023 10:08:52 GMT", "version": "v1" }, { "created": "Thu, 14 Dec 2023 02:47:32 GMT", "version": "v2" } ]
2023-12-25
[ [ "Yu", "Shuo-Ying", "" ], [ "Kang", "Xian-Wei", "" ] ]
We study the radiative decay of $X(3872)$ based on the assumption that $X(3872)$ is regarded as a $c\overline{c}$ charmonium with quantum number $J^{PC}=1^{++}$ ($J,\,P,\,C$ represent the spin, parity and charge conjugation, respectively). The form factors of $X(3872)$ transitions to $J/\psi\gamma$ and $\psi'\gamma$ ($\psi'$ denotes $\psi(2S)$ throughout the paper) are calculated in the framework of the covariant light-front quark model. The phenomenological wave function of a meson depends on the parameter $\beta$, whose inverse essentially describes the confinement scale. In the present work, the parameters $\beta$ for the vector $J/\psi$ and $\psi'$ mesons will be determined through their decay constants, which are obtained from the experimental values of their partial decay widths to the electron-positron pair. For $X(3872)$, we determined the value of $\beta$ by the decay width of $X(3872)\rightarrow \psi'\gamma$. Then, we examined the width of $X(3872)\to J/\psi\gamma$ in a manner of parameter-free prediction and compared it with the experimental value. As a result, an inconsistency or contradiction occurs between the widths of $X(3872)\to J/\psi\gamma$ and $X(3872)\to \psi'\gamma$. We thus conclude that $X(3872)$ cannot be a pure $c\overline c$ resonance and that other components are necessary in its wave function.
2405.03746
Kevin Hinze
Stefan Antusch, Kevin Hinze, Shaikh Saad, and Jonathan Steiner
Probing SUSY at Gravitational Wave Observatories
5 pages + appendix + references, 4 figures
null
null
null
hep-ph astro-ph.CO hep-th
http://creativecommons.org/licenses/by/4.0/
Under the assumption that the recent pulsar timing array evidence for a stochastic gravitational wave (GW) background at nanohertz frequencies is generated by metastable cosmic strings, we analyze the potential of present and future GW observatories for probing the change of particle degrees of freedom caused, e.g., by a supersymmetric (SUSY) extension of the Standard Model (SM). We find that signs of the characteristic doubling of degrees of freedom predicted by SUSY could be detected at Einstein Telescope and Cosmic Explorer even if the masses of the SUSY partner particles are as high as about $10^4$ TeV, far above the reach of any currently envisioned particle collider. We also discuss the detection prospects for the case that some entropy production, e.g. from a late decaying modulus field inducing a temporary matter domination phase in the evolution of the universe, somewhat dilutes the GW spectrum, delaying discovery of the stochastic GW background at LIGO-Virgo-KAGRA. In our analysis we focus on SUSY, but any theory beyond the SM predicting a significant increase of particle degrees of freedom could be probed this way.
[ { "created": "Mon, 6 May 2024 18:00:00 GMT", "version": "v1" } ]
2024-05-08
[ [ "Antusch", "Stefan", "" ], [ "Hinze", "Kevin", "" ], [ "Saad", "Shaikh", "" ], [ "Steiner", "Jonathan", "" ] ]
Under the assumption that the recent pulsar timing array evidence for a stochastic gravitational wave (GW) background at nanohertz frequencies is generated by metastable cosmic strings, we analyze the potential of present and future GW observatories for probing the change of particle degrees of freedom caused, e.g., by a supersymmetric (SUSY) extension of the Standard Model (SM). We find that signs of the characteristic doubling of degrees of freedom predicted by SUSY could be detected at Einstein Telescope and Cosmic Explorer even if the masses of the SUSY partner particles are as high as about $10^4$ TeV, far above the reach of any currently envisioned particle collider. We also discuss the detection prospects for the case that some entropy production, e.g. from a late decaying modulus field inducing a temporary matter domination phase in the evolution of the universe, somewhat dilutes the GW spectrum, delaying discovery of the stochastic GW background at LIGO-Virgo-KAGRA. In our analysis we focus on SUSY, but any theory beyond the SM predicting a significant increase of particle degrees of freedom could be probed this way.
1009.3314
Yu-Xin Liu
Yuan Mo, Si-xue Qin, and Yu-xin Liu
Temperature Dependence of the Effective Bag Constant and the Radius of a Nucleon in the Global Color Symmetry Model of QCD
10 pages, 9 figures
Phys.Rev.C82:025206,2010
10.1103/PhysRevC.82.025206
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the temperature dependence of the effective bag constant, the mass, and the radius of a nucleon in the formalism of the simple global color symmetry model in the Dyson-Schwinger equation approach of QCD with a Gaussian-type effective gluon propagator. We obtain that, as the temperature is lower than a critical value, the effective bag constant and the mass decrease and the radius increases with the temperature increasing. As the critical temperature is reached, the effective bag constant and the mass vanish and the radius tends to infinity. At the same time, the chiral quark condensate disappears. These phenomena indicate that the deconfinement and the chiral symmetry restoration phase transitions can take place at high temperature. The dependence of the critical temperature on the interaction strength parameter in the effective gluon propagator of the approach is given.
[ { "created": "Fri, 17 Sep 2010 02:06:01 GMT", "version": "v1" } ]
2011-10-17
[ [ "Mo", "Yuan", "" ], [ "Qin", "Si-xue", "" ], [ "Liu", "Yu-xin", "" ] ]
We study the temperature dependence of the effective bag constant, the mass, and the radius of a nucleon in the formalism of the simple global color symmetry model in the Dyson-Schwinger equation approach of QCD with a Gaussian-type effective gluon propagator. We obtain that, as the temperature is lower than a critical value, the effective bag constant and the mass decrease and the radius increases with the temperature increasing. As the critical temperature is reached, the effective bag constant and the mass vanish and the radius tends to infinity. At the same time, the chiral quark condensate disappears. These phenomena indicate that the deconfinement and the chiral symmetry restoration phase transitions can take place at high temperature. The dependence of the critical temperature on the interaction strength parameter in the effective gluon propagator of the approach is given.
2112.10402
Ulas Ozdem
U. Ozdem
Magnetic moments of the doubly charged axial-vector $T_{cc}^{++}$ states
10 pages, 1 figure and 1 table. The text has been significantly modified
null
10.1103/PhysRevD.105.054019
null
hep-ph hep-ex hep-lat
http://creativecommons.org/licenses/by/4.0/
Motivated by the discovery of the doubly-charmed state $T^+_{cc}$ and with the help of light-cone sum rules, the magnetic moments of possible $T_{cc}^{++}$ states are calculated. While calculating the magnetic moments of these states, these particles are considered in the molecular picture and they have $J^P = 1^+$ quantum numbers. The magnetic moment results obtained for the $T_{cc}^{++}$ states are large due to the double electric charge. The results obtained in this study can be checked using other theoretical models. The magnetic moments of the hadrons reveal valuable knowledge about the size and the shape of the hadrons. Measurement of the magnetic moment of the $T_{cc}^{++}$ states in future experimental collaborations can be very useful to understanding substructure and identification the quantum numbers of these states.
[ { "created": "Mon, 20 Dec 2021 08:50:02 GMT", "version": "v1" }, { "created": "Sat, 5 Feb 2022 11:46:45 GMT", "version": "v2" } ]
2022-04-06
[ [ "Ozdem", "U.", "" ] ]
Motivated by the discovery of the doubly-charmed state $T^+_{cc}$ and with the help of light-cone sum rules, the magnetic moments of possible $T_{cc}^{++}$ states are calculated. While calculating the magnetic moments of these states, these particles are considered in the molecular picture and they have $J^P = 1^+$ quantum numbers. The magnetic moment results obtained for the $T_{cc}^{++}$ states are large due to the double electric charge. The results obtained in this study can be checked using other theoretical models. The magnetic moments of the hadrons reveal valuable knowledge about the size and the shape of the hadrons. Measurement of the magnetic moment of the $T_{cc}^{++}$ states in future experimental collaborations can be very useful to understanding substructure and identification the quantum numbers of these states.
hep-ph/9908428
Kunihiko Terasaki
K. Terasaki
Non-factorizable contribution in nonleptonic weak interactions of K mesons
23 pages,1 figure
Int.J.Mod.Phys.A16:1605-1630,2001
10.1142/S0217751X01003305
YITP-99-42
hep-ph
null
Two pion decays of K mesons, K_L-K_S mass difference, two photon and the Dalitz decays of K_L are studied systematically by assuming that their amplitude is given by a sum of factorizable and non-factorizable ones. The former is estimated by using a naive factorization while the latter is assumed to be dominated by dynamical contributions of various hadron states.
[ { "created": "Fri, 20 Aug 1999 20:52:06 GMT", "version": "v1" } ]
2014-11-17
[ [ "Terasaki", "K.", "" ] ]
Two pion decays of K mesons, K_L-K_S mass difference, two photon and the Dalitz decays of K_L are studied systematically by assuming that their amplitude is given by a sum of factorizable and non-factorizable ones. The former is estimated by using a naive factorization while the latter is assumed to be dominated by dynamical contributions of various hadron states.
1512.08752
J. A. R. Cembranos
Jose A. R. Cembranos
Modified gravity and dark matter
5 pages, 1 figure, invited contribution to TAUP 2015, to appear in the Proceedings of the XIV International Conference on Topics in Astroparticle and Underground Physics, 7-11 September 2015,Torino, Italy
null
10.1088/1742-6596/718/3/032004
null
hep-ph astro-ph.CO gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The fundamental nature of Dark Matter (DM) has not been established. Indeed, beyond its gravitational effects, DM remains undetected by present experiments. In this situation, it is reasonable to wonder if other alternatives can effectively explain the observations usually associated with the existence of DM. The modification of the gravitational interaction has been studied in this context from many different approaches. However, the large amount of different astrophysical evidences makes difficult to think that modified gravity can account for all these observations. On the other hand, if such a modification introduces new degrees of freedom, they may work as DM candidates. We will summarize the phenomenology of these gravitational dark matter candidates by analyzing minimal models.
[ { "created": "Tue, 29 Dec 2015 18:51:17 GMT", "version": "v1" } ]
2016-06-22
[ [ "Cembranos", "Jose A. R.", "" ] ]
The fundamental nature of Dark Matter (DM) has not been established. Indeed, beyond its gravitational effects, DM remains undetected by present experiments. In this situation, it is reasonable to wonder if other alternatives can effectively explain the observations usually associated with the existence of DM. The modification of the gravitational interaction has been studied in this context from many different approaches. However, the large amount of different astrophysical evidences makes difficult to think that modified gravity can account for all these observations. On the other hand, if such a modification introduces new degrees of freedom, they may work as DM candidates. We will summarize the phenomenology of these gravitational dark matter candidates by analyzing minimal models.
2204.11604
Xuanmin Cao
Xuanmin Cao, Jingyi Chao, Hui Liu, and Danning Li
Thermalization and prethermalization in the soft-wall AdS/QCD model
16 pages, 15 figures
null
10.1103/PhysRevD.107.086001
null
hep-ph
http://creativecommons.org/licenses/by-nc-sa/4.0/
The real-time dynamics of chiral phase transition is investigated in a two-flavor ($N_f=2$) soft-wall AdS/QCD model. To understand the dynamics of thermalization, we quench the system from initial states deviating from the equilibrium states. Then, we solve the nonequilibrium evolution of the order parameter (chiral condensate $\langle \sigma\equiv\bar{q}q\rangle$). It is shown that the system undergoes an exponential relaxation at temperatures away from the critical temperature $T_c$. The relaxation time diverges at $T_c$, presenting a typical behavior of critical slowing down. Numerically, we extract the dynamic critical exponent $z$, and get $z\approx 2$ by fitting the scaling behavior $\sigma\propto t^{-\beta/(\nu z)}$, where the mean-field static critical exponents (order parameter critical exponent $\beta=1/2$, correlation length critical exponent $\nu=1/2$ ) have been applied. More interestingly, it is remarked that, for a large class of initial states, the system would linger over a quasi-steady state for a certain period of time before the thermalization. It is suggested that the interesting phenomenon, known as prethermalization, has been observed in the framework of holographic models. In such prethermal stage, we verify that the system is characterized by a universal dynamical scaling law and described by the initial-slip exponent $\theta=0$.
[ { "created": "Mon, 25 Apr 2022 12:37:57 GMT", "version": "v1" }, { "created": "Tue, 28 Mar 2023 04:49:10 GMT", "version": "v2" } ]
2023-04-19
[ [ "Cao", "Xuanmin", "" ], [ "Chao", "Jingyi", "" ], [ "Liu", "Hui", "" ], [ "Li", "Danning", "" ] ]
The real-time dynamics of chiral phase transition is investigated in a two-flavor ($N_f=2$) soft-wall AdS/QCD model. To understand the dynamics of thermalization, we quench the system from initial states deviating from the equilibrium states. Then, we solve the nonequilibrium evolution of the order parameter (chiral condensate $\langle \sigma\equiv\bar{q}q\rangle$). It is shown that the system undergoes an exponential relaxation at temperatures away from the critical temperature $T_c$. The relaxation time diverges at $T_c$, presenting a typical behavior of critical slowing down. Numerically, we extract the dynamic critical exponent $z$, and get $z\approx 2$ by fitting the scaling behavior $\sigma\propto t^{-\beta/(\nu z)}$, where the mean-field static critical exponents (order parameter critical exponent $\beta=1/2$, correlation length critical exponent $\nu=1/2$ ) have been applied. More interestingly, it is remarked that, for a large class of initial states, the system would linger over a quasi-steady state for a certain period of time before the thermalization. It is suggested that the interesting phenomenon, known as prethermalization, has been observed in the framework of holographic models. In such prethermal stage, we verify that the system is characterized by a universal dynamical scaling law and described by the initial-slip exponent $\theta=0$.
2006.06582
Prasanth Shyamsundar
Konstantin T. Matchev, Alexander Roman, Prasanth Shyamsundar
Finding Wombling Boundaries in LHC Data with Voronoi and Delaunay Tessellations
54 pages. New figure 13 and appendix A added. Conclusions unchanged. Matches published version
J. High Energ. Phys. 12 (2020), 137
10.1007/JHEP12(2020)137
null
hep-ph hep-ex physics.comp-ph physics.data-an
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We address the problem of finding a wombling boundary in point data generated by a general Poisson point process, a specific example of which is an LHC event sample distributed in the phase space of a final state signature, with the wombling boundary created by some new physics. We discuss the use of Voronoi and Delaunay tessellations of the point data for estimating the local gradients and investigate methods for sharpening the boundaries by reducing the statistical noise. The outcome from traditional wombling algorithms is a set of boundary cell candidates with relatively large gradients, whose spatial properties must then be scrutinized in order to construct the boundary and evaluate its significance. Here we propose an alternative approach where we simultaneously form and evaluate the significance of all possible boundaries in terms of the total gradient flux. We illustrate our method with several toy examples of both straight and curved boundaries with varying amounts of signal present in the data.
[ { "created": "Mon, 8 Jun 2020 22:23:42 GMT", "version": "v1" }, { "created": "Sun, 10 Jan 2021 17:25:39 GMT", "version": "v2" } ]
2021-01-12
[ [ "Matchev", "Konstantin T.", "" ], [ "Roman", "Alexander", "" ], [ "Shyamsundar", "Prasanth", "" ] ]
We address the problem of finding a wombling boundary in point data generated by a general Poisson point process, a specific example of which is an LHC event sample distributed in the phase space of a final state signature, with the wombling boundary created by some new physics. We discuss the use of Voronoi and Delaunay tessellations of the point data for estimating the local gradients and investigate methods for sharpening the boundaries by reducing the statistical noise. The outcome from traditional wombling algorithms is a set of boundary cell candidates with relatively large gradients, whose spatial properties must then be scrutinized in order to construct the boundary and evaluate its significance. Here we propose an alternative approach where we simultaneously form and evaluate the significance of all possible boundaries in terms of the total gradient flux. We illustrate our method with several toy examples of both straight and curved boundaries with varying amounts of signal present in the data.
1612.08420
Jose Antonio Oller
Xian-Wei Kang, J. A. Oller
Different pole structures in line shapes of the $X(3872)$
43 pages, 9 figures, 3 tables. The paper has been much extended. Extra algebraic derivations and matching with QFT models are also included
null
10.1140/epjc/s10052-017-4961-z
null
hep-ph hep-ex nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We introduce a near-threshold parameterization that is more general than the effective-range expansion up to and including the effective-range because it can also handle with a near-threshold zero in the $D^0\bar{D}^{*0}$ $S$-wave. In terms of it we analyze the CDF data on inclusive $p\bar{p}$ scattering to $J/\psi \pi^+\pi^-$, and the Belle and BaBar data on $B$ decays to $K\, J/\psi \pi^+\pi^-$ and $K D\bar{D}^{*0}$ around the $D^0\bar{D}^{*0}$ threshold. It is shown that data can be reproduced with similar quality for the $X(3872)$ being a bound {\it and/or} a virtual state. We also find that the $X(3872)$ might be a higher-order virtual-state pole (double or triplet pole), in the limit in which the small $D^{*0}$ width vanishes. Once the latter is restored the corrections to the pole position are non-analytic and much bigger than the $D^{*0}$ width itself. The $X(3872)$ compositeness coefficient in $D^0\bar{D}^{*0}$ ranges from nearly 0 up to 1 in the different scenarios.
[ { "created": "Mon, 26 Dec 2016 18:24:38 GMT", "version": "v1" }, { "created": "Wed, 17 May 2017 09:08:49 GMT", "version": "v2" } ]
2017-08-02
[ [ "Kang", "Xian-Wei", "" ], [ "Oller", "J. A.", "" ] ]
We introduce a near-threshold parameterization that is more general than the effective-range expansion up to and including the effective-range because it can also handle with a near-threshold zero in the $D^0\bar{D}^{*0}$ $S$-wave. In terms of it we analyze the CDF data on inclusive $p\bar{p}$ scattering to $J/\psi \pi^+\pi^-$, and the Belle and BaBar data on $B$ decays to $K\, J/\psi \pi^+\pi^-$ and $K D\bar{D}^{*0}$ around the $D^0\bar{D}^{*0}$ threshold. It is shown that data can be reproduced with similar quality for the $X(3872)$ being a bound {\it and/or} a virtual state. We also find that the $X(3872)$ might be a higher-order virtual-state pole (double or triplet pole), in the limit in which the small $D^{*0}$ width vanishes. Once the latter is restored the corrections to the pole position are non-analytic and much bigger than the $D^{*0}$ width itself. The $X(3872)$ compositeness coefficient in $D^0\bar{D}^{*0}$ ranges from nearly 0 up to 1 in the different scenarios.
1011.1448
Jose Antonio Oller
J. A. Oller, J. M. Alarcon, M. Albaladejo, L. Alvarez-Ruso and L. Roca
Hadron resonances generated from the dynamics of the lightest scalar ones
4 pafes, 4 figures. Invited talk at QCD 10 (25th anniversary), 15th International QCD Conference, 28th June - 3rd July 2010 Montpellier (France). To be published in Nucl. Phys. B (Proc. Suppl.)
Nucl.Phys.Proc.Suppl.207-208:188-191,2010
10.1016/j.nuclphysbps.2010.10.049
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We have studied the interactions of the scalar resonances f_0(980) and a_0(980) with the vector resonance \phi(1020) and with the lightest pseudoscalars \pi, K, \eta and \eta'. We first obtain the interaction kernels without including any new free parameter. Afterwards, the interaction kernels are unitarized and the final S-wave amplitudes result. We find that these interactions are very rich and generate a large amount of pseudoscalar resonances including the K(1460), \pi(1300), \pi(1800), \eta(1475) and X(1835) resonances. The f_0(980)\phi(1020) self-interactions give rise to the \phi(2170) resonance. For realistic choices of the parameters we also obtain an isovector companion in the same mass region from the a_0(980) \phi(1020) interactions.
[ { "created": "Fri, 5 Nov 2010 16:15:37 GMT", "version": "v1" } ]
2011-04-20
[ [ "Oller", "J. A.", "" ], [ "Alarcon", "J. M.", "" ], [ "Albaladejo", "M.", "" ], [ "Alvarez-Ruso", "L.", "" ], [ "Roca", "L.", "" ] ]
We have studied the interactions of the scalar resonances f_0(980) and a_0(980) with the vector resonance \phi(1020) and with the lightest pseudoscalars \pi, K, \eta and \eta'. We first obtain the interaction kernels without including any new free parameter. Afterwards, the interaction kernels are unitarized and the final S-wave amplitudes result. We find that these interactions are very rich and generate a large amount of pseudoscalar resonances including the K(1460), \pi(1300), \pi(1800), \eta(1475) and X(1835) resonances. The f_0(980)\phi(1020) self-interactions give rise to the \phi(2170) resonance. For realistic choices of the parameters we also obtain an isovector companion in the same mass region from the a_0(980) \phi(1020) interactions.
hep-ph/0004102
Eli Waxman
E. Waxman (Weizmann Inst.)
Gamma-Ray Bursts
7 pages; Invited talk presented at the 7th International Symposium on Particles, Strings and Cosmology (Dec. 1999, Lake Tahoe, California)
null
10.1142/9789812792433_0061
null
hep-ph astro-ph
null
Ultra-high-energy, >10^19 eV, cosmic-ray and high energy, ~10^14 eV, neutrino production in GRBs is discussed in the light of recent GRB and cosmic-ray observations. Emphasis is put on model predictions that can be tested with operating and planned cosmic-ray and neutrino detectors, and on the prospects of testing for neutrino properties.
[ { "created": "Tue, 11 Apr 2000 14:10:43 GMT", "version": "v1" } ]
2016-11-03
[ [ "Waxman", "E.", "", "Weizmann Inst." ] ]
Ultra-high-energy, >10^19 eV, cosmic-ray and high energy, ~10^14 eV, neutrino production in GRBs is discussed in the light of recent GRB and cosmic-ray observations. Emphasis is put on model predictions that can be tested with operating and planned cosmic-ray and neutrino detectors, and on the prospects of testing for neutrino properties.
hep-ph/9304208
Hans Eggers
H.C. Eggers, P. Lipa, P. Carruthers and B. Buschbeck
Integral correlation measures for multiparticle physics
23 pages, 6 tar-compressed uuencoded PostScript figures appended, preprint TPR-92-47
Phys.Rev. D48 (1993) 2040-2053
10.1103/PhysRevD.48.2040
null
hep-ph
null
We report on a considerable improvement in the technique of measuring multiparticle correlations via integrals over correlation functions. A modification of measures used in the characterization of chaotic dynamical sytems permits fast and flexible calculation of factorial moments and cumulants as well as their differential versions. Higher order correlation integral measurements even of large multiplicity events such as encountered in heavy ion collisons are now feasible. The change from ``ordinary'' to ``factorial'' powers may have important consequences in other fields such as the study of galaxy correlations and Bose-Einstein interferometry.
[ { "created": "Sat, 3 Apr 1993 17:15:02 GMT", "version": "v1" } ]
2009-10-22
[ [ "Eggers", "H. C.", "" ], [ "Lipa", "P.", "" ], [ "Carruthers", "P.", "" ], [ "Buschbeck", "B.", "" ] ]
We report on a considerable improvement in the technique of measuring multiparticle correlations via integrals over correlation functions. A modification of measures used in the characterization of chaotic dynamical sytems permits fast and flexible calculation of factorial moments and cumulants as well as their differential versions. Higher order correlation integral measurements even of large multiplicity events such as encountered in heavy ion collisons are now feasible. The change from ``ordinary'' to ``factorial'' powers may have important consequences in other fields such as the study of galaxy correlations and Bose-Einstein interferometry.
0912.2676
Christopher Orme
Christopher Orme
CP-violation reach of an electron capture neutrino beam
18 pages, 11 figures. Contains and extended analysis. Matches accepted JHEP version
JHEP 1007:049,2010
10.1007/JHEP07(2010)049
IPPP /09/90, DCPT /09/;180, EUROnu-WP6-09-13
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This article extends the work of Bernabeu and Espinoza by examining the CP-violation reach of a $^{150}$Dy electron capture beam through the variation of the two Lorentz boosts, the number of useful electron capture decays, the relative run time of each boost and the number of atmospheric backgrounds. The neutrinos are assumed to be sourced at CERN with an upgraded SPS and are directed towards a 440 kton Water Cerenkov detector located at the Canfranc laboratory. Two large `CP-coverage' choices for the boost pairings are found; a $\delta$-symmetrical coverage for $(\gamma_{1}, \gamma_{2})$ = (280, 160) and an $\delta$-asymmetric coverage for $(\gamma_{1}, \gamma_{2})$ = (440,150). With a nominal useful decay rate of $N_{\rm ions} = 10^{18}$ ions per year, the $\delta$-symmetric setup can rule out CP-conservation down to $\sin^{2}2\theta_{13} = 3\cdot 10^{-4}$. To reach $\sin^{2}2\theta_{13} = 1\cdot 10^{-3}$ for both $\delta < 0$ and $\delta > 0$ requires a useful decay rate of $N_{\rm ions} = 6\cdot 10^{17}$ ions per year.
[ { "created": "Mon, 14 Dec 2009 19:16:41 GMT", "version": "v1" }, { "created": "Mon, 12 Jul 2010 18:58:11 GMT", "version": "v2" } ]
2011-03-28
[ [ "Orme", "Christopher", "" ] ]
This article extends the work of Bernabeu and Espinoza by examining the CP-violation reach of a $^{150}$Dy electron capture beam through the variation of the two Lorentz boosts, the number of useful electron capture decays, the relative run time of each boost and the number of atmospheric backgrounds. The neutrinos are assumed to be sourced at CERN with an upgraded SPS and are directed towards a 440 kton Water Cerenkov detector located at the Canfranc laboratory. Two large `CP-coverage' choices for the boost pairings are found; a $\delta$-symmetrical coverage for $(\gamma_{1}, \gamma_{2})$ = (280, 160) and an $\delta$-asymmetric coverage for $(\gamma_{1}, \gamma_{2})$ = (440,150). With a nominal useful decay rate of $N_{\rm ions} = 10^{18}$ ions per year, the $\delta$-symmetric setup can rule out CP-conservation down to $\sin^{2}2\theta_{13} = 3\cdot 10^{-4}$. To reach $\sin^{2}2\theta_{13} = 1\cdot 10^{-3}$ for both $\delta < 0$ and $\delta > 0$ requires a useful decay rate of $N_{\rm ions} = 6\cdot 10^{17}$ ions per year.
hep-ph/0702138
Shigeru Odaka
S. Odaka and Y. Kurihara
Initial-state parton shower kinematics for NLO event generators
10 pages, 6 figures; minor changes in the abstract and the text according to the comments from the referee
Eur.Phys.J.C51:867-873,2007
10.1140/epjc/s10052-007-0342-3
null
hep-ph
null
We are developing a consistent method to combine tree-level event generators for hadron collision interactions with those including one additional QCD radiation from the initial-state partons, based on the limited leading-log (LLL) subtraction method, aiming at an application to NLO event generators. In this method, a boundary between non-radiative and radiative processes necessarily appears at the factorization scale (mu_F). The radiation effects are simulated using a parton shower (PS) in non-radiative processes. It is therefore crucial in our method to apply a PS which well reproduces the radiation activities evaluated from the matrix-element (ME) calculations for radiative processes. The PS activity depends on the applied kinematics model. In this paper we introduce two models for our simple initial-state leading-log PS: a model similar to the "old" PYTHIA-PS and a p_T-prefixed model motivated by ME calculations. PS simulations employing these models are tested using W-boson production at LHC as an example. Both simulations show a smooth matching to the LLL-subtracted W + 1 jet simulation in the p_T distribution of W bosons, and the summed p_T spectra are stable against a variation of mu_F, despite that the p_T-prefixed PS results in an apparently harder p_T spectrum.
[ { "created": "Wed, 14 Feb 2007 05:06:22 GMT", "version": "v1" }, { "created": "Fri, 8 Jun 2007 05:49:11 GMT", "version": "v2" } ]
2008-11-26
[ [ "Odaka", "S.", "" ], [ "Kurihara", "Y.", "" ] ]
We are developing a consistent method to combine tree-level event generators for hadron collision interactions with those including one additional QCD radiation from the initial-state partons, based on the limited leading-log (LLL) subtraction method, aiming at an application to NLO event generators. In this method, a boundary between non-radiative and radiative processes necessarily appears at the factorization scale (mu_F). The radiation effects are simulated using a parton shower (PS) in non-radiative processes. It is therefore crucial in our method to apply a PS which well reproduces the radiation activities evaluated from the matrix-element (ME) calculations for radiative processes. The PS activity depends on the applied kinematics model. In this paper we introduce two models for our simple initial-state leading-log PS: a model similar to the "old" PYTHIA-PS and a p_T-prefixed model motivated by ME calculations. PS simulations employing these models are tested using W-boson production at LHC as an example. Both simulations show a smooth matching to the LLL-subtracted W + 1 jet simulation in the p_T distribution of W bosons, and the summed p_T spectra are stable against a variation of mu_F, despite that the p_T-prefixed PS results in an apparently harder p_T spectrum.
0903.1696
Andre Sternbeck
Lorenz von Smekal, Kim Maltman, Andre Sternbeck
The strong coupling and its running to four loops in a minimal MOM scheme
8 pages, 4 tables. Revised and extended version accepted for publication in PLB. References and a note on quark mass effects added
Phys.Lett.B681:336-342,2009
10.1016/j.physletb.2009.10.030
ADP-09-03/T681
hep-ph hep-lat
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We introduce the minimal momentum subtraction (MiniMOM) scheme for QCD. Its definition allows the strong coupling to be fixed solely through a determination of the gluon and ghost propagators. In Landau gauge this scheme has been implicit in the early studies of these propagators, especially in relation to their non-perturbative behaviour in the infrared and the associated infrared fixed-point. Here we concentrate on its perturbative use. We give the explicit perturbative definition of the scheme and the relation of its beta-function and running coupling to the MSbar scheme up to 4-loop order in general covariant gauges. We also demonstrate, by considering a selection of N_f=3 examples, that the apparent convergence of the relevant perturbative series can in some (though not all) cases be significantly improved by re-expanding the MSbar coupling version of this series in terms of the MiniMOM coupling, making the MiniMOM coupling also of potential interest in certain phenomenological applications.
[ { "created": "Tue, 10 Mar 2009 06:40:02 GMT", "version": "v1" }, { "created": "Wed, 21 Oct 2009 18:49:21 GMT", "version": "v2" } ]
2010-04-28
[ [ "von Smekal", "Lorenz", "" ], [ "Maltman", "Kim", "" ], [ "Sternbeck", "Andre", "" ] ]
We introduce the minimal momentum subtraction (MiniMOM) scheme for QCD. Its definition allows the strong coupling to be fixed solely through a determination of the gluon and ghost propagators. In Landau gauge this scheme has been implicit in the early studies of these propagators, especially in relation to their non-perturbative behaviour in the infrared and the associated infrared fixed-point. Here we concentrate on its perturbative use. We give the explicit perturbative definition of the scheme and the relation of its beta-function and running coupling to the MSbar scheme up to 4-loop order in general covariant gauges. We also demonstrate, by considering a selection of N_f=3 examples, that the apparent convergence of the relevant perturbative series can in some (though not all) cases be significantly improved by re-expanding the MSbar coupling version of this series in terms of the MiniMOM coupling, making the MiniMOM coupling also of potential interest in certain phenomenological applications.