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1506.08996
Yi Liao
Zhi-Long Han (Nankai Univ.), Ran Ding (Peking Univ.), Yi Liao (ITP-CAS, Peking Univ., Nankai Univ.)
LHC Phenomenology of the Type II Seesaw Mechanism: Observability of Neutral Scalars in the Nondegenerate Case
v1: 32 pages, 17 figures, 3 tables. v2: added 2 refs (2nd in [61] and [66]), revised Acknowledgments, and corrected grammatical errors according to proofs; no other changes
Phys. Rev. D 92, 033014 (2015)
10.1103/PhysRevD.92.033014
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This is a sequel to our previous work on LHC phenomenology of the type II seesaw model in the nondegenerate case. In this work, we further study the pair and associated production of the neutral scalars H^0/A^0. We restrict ourselves to the so-called negative scenario characterized by the mass order M_{H^{\pm\pm}}>M_{H^\pm}>M_{H^0/A^0}, in which the H^0/A^0 production receives significant enhancement from cascade decays of the charged scalars H^{\pm\pm},~H^\pm. We consider three important signal channels---b\bar{b}\gamma\gamma, b\bar{b}\tau^+\tau^-, $b\bar{b}\ell^+\ell^-\cancel{E}_T$---and perform detailed simulations. We find that at the 14 TeV LHC with an integrated luminosity of 3000/fb, a 5\sigma mass reach of 151, 150, and 180 GeV, respectively, is possible in the three channels from the pure Drell-Yan H^0A^0 production, while the cascade-decay-enhanced H^0/A^0 production can push the mass limit further to 164, 177, and 200 GeV. The neutral scalars in the negative scenario are thus accessible at LHC run II.
[ { "created": "Tue, 30 Jun 2015 09:09:05 GMT", "version": "v1" }, { "created": "Sat, 5 Sep 2015 10:19:31 GMT", "version": "v2" } ]
2015-09-08
[ [ "Han", "Zhi-Long", "", "Nankai Univ." ], [ "Ding", "Ran", "", "Peking Univ." ], [ "Liao", "Yi", "", "ITP-CAS, Peking Univ., Nankai Univ." ] ]
This is a sequel to our previous work on LHC phenomenology of the type II seesaw model in the nondegenerate case. In this work, we further study the pair and associated production of the neutral scalars H^0/A^0. We restrict ourselves to the so-called negative scenario characterized by the mass order M_{H^{\pm\pm}}>M_{H^\pm}>M_{H^0/A^0}, in which the H^0/A^0 production receives significant enhancement from cascade decays of the charged scalars H^{\pm\pm},~H^\pm. We consider three important signal channels---b\bar{b}\gamma\gamma, b\bar{b}\tau^+\tau^-, $b\bar{b}\ell^+\ell^-\cancel{E}_T$---and perform detailed simulations. We find that at the 14 TeV LHC with an integrated luminosity of 3000/fb, a 5\sigma mass reach of 151, 150, and 180 GeV, respectively, is possible in the three channels from the pure Drell-Yan H^0A^0 production, while the cascade-decay-enhanced H^0/A^0 production can push the mass limit further to 164, 177, and 200 GeV. The neutral scalars in the negative scenario are thus accessible at LHC run II.
1411.7615
Leonardo Tinti
Leonardo Tinti
New formulation of leading order anisotropic hydrodynamics
Talk presented at Hot Quarks 2014, September 21-28, 2014, Las Negras, Andalucia, Spain
null
10.1088/1742-6596/612/1/012061
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Anisotropic hydrodynamics is a reorganization of the relativistic hydrodynamics expansion, with the leading order already containing substantial momentum-space anisotropies. The latter are a cause of concern in the traditional viscous hydrodynamics, since large momentum anisotropies generated in ultrarelativistic heavy-ion collisions are not consistent with the hypothesis of small deviations from an isotropic background, i.e., from the local equilibrium distribution. We discuss the leading order of the expansion, presenting a new formulation for the (1+1)--dimensional case, namely, for the longitudinally boost invariant and cylindrically symmetric flow. This new approach is consistent with the well established framework of Israel and Stewart in the close to equilibrium limit (where we expect viscous hydrodynamics to work well). If we consider the (0+1)--dimensional case, that is, transversally homogeneous and longitudinally boost invariant flow, {the new form of anisotropic hydrodynamics leads to better agreement with known solutions} of the Boltzmann equation than the previous formulations, especially when we consider finite mass particles.
[ { "created": "Thu, 27 Nov 2014 14:55:16 GMT", "version": "v1" } ]
2015-06-11
[ [ "Tinti", "Leonardo", "" ] ]
Anisotropic hydrodynamics is a reorganization of the relativistic hydrodynamics expansion, with the leading order already containing substantial momentum-space anisotropies. The latter are a cause of concern in the traditional viscous hydrodynamics, since large momentum anisotropies generated in ultrarelativistic heavy-ion collisions are not consistent with the hypothesis of small deviations from an isotropic background, i.e., from the local equilibrium distribution. We discuss the leading order of the expansion, presenting a new formulation for the (1+1)--dimensional case, namely, for the longitudinally boost invariant and cylindrically symmetric flow. This new approach is consistent with the well established framework of Israel and Stewart in the close to equilibrium limit (where we expect viscous hydrodynamics to work well). If we consider the (0+1)--dimensional case, that is, transversally homogeneous and longitudinally boost invariant flow, {the new form of anisotropic hydrodynamics leads to better agreement with known solutions} of the Boltzmann equation than the previous formulations, especially when we consider finite mass particles.
hep-ph/9306326
null
Kin-Wang Ng (Institute of Physics, Academia Sinica, Taiwan)
Cosmological Bound on the Decay $\pi^0\rightarrow\gamma X$
7 pages, IP-ASTP-03-93
Phys.Rev.D48:2941-2942,1993
10.1103/PhysRevD.48.2941
null
hep-ph
null
Using the upper bound on the effective number of light neutrino species during primordial nucleosynthesis and the cosmological pion-pole mechanism $\gamma\gamma\rightarrow \pi^0\rightarrow \gamma X$, we obtain an upper limit on the branching ratio for the decay BR$(\pi^0\rightarrow \gamma X)<3\times 10^{-13}$, where $X$ is any long-lived weakly interacting neutral vector particle with mass smaller than the neutral pion mass.
[ { "created": "Tue, 29 Jun 1993 17:32:00 GMT", "version": "v1" } ]
2008-11-26
[ [ "Ng", "Kin-Wang", "", "Institute of Physics, Academia Sinica, Taiwan" ] ]
Using the upper bound on the effective number of light neutrino species during primordial nucleosynthesis and the cosmological pion-pole mechanism $\gamma\gamma\rightarrow \pi^0\rightarrow \gamma X$, we obtain an upper limit on the branching ratio for the decay BR$(\pi^0\rightarrow \gamma X)<3\times 10^{-13}$, where $X$ is any long-lived weakly interacting neutral vector particle with mass smaller than the neutral pion mass.
0912.4348
Dominik Schwarz
Dominik J. Schwarz and Erandy Ramirez
Just enough inflation
4 pages, 2 figures, talk presented at MG12, Paris, 2009
null
null
BI-TP 2009/32
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose a version of chaotic inflation, in which a fundamental scale M, well below the Planck scale M_P, fixes the initial value of the effective potential. If this scale happens to be the scale of grand unified theories, there are just enough e-foldings of inflation. An initial epoch of fast-roll breaks scale-invariance at the largest observable scales.
[ { "created": "Tue, 22 Dec 2009 09:39:42 GMT", "version": "v1" } ]
2009-12-23
[ [ "Schwarz", "Dominik J.", "" ], [ "Ramirez", "Erandy", "" ] ]
We propose a version of chaotic inflation, in which a fundamental scale M, well below the Planck scale M_P, fixes the initial value of the effective potential. If this scale happens to be the scale of grand unified theories, there are just enough e-foldings of inflation. An initial epoch of fast-roll breaks scale-invariance at the largest observable scales.
hep-ph/0309302
Masahisa Matsuda
Takemi Hayashi, Masahisa Matsuda and Takeo Matsuoka
Particle Spectra and Gauge Unification in $SU(6) \times SU(2)_R$ Model
28 pages, 1 figure
Prog.Theor.Phys. 110 (2004) 1095-1115
10.1143/PTP.110.1095
AUE-03-01/KGKU-03-01
hep-ph
null
We study the path from the string scale physics to the low-energy physics in the $SU(6) \times SU(2)_R$ string-inspired model with the flavor symmetry ${\bf Z}_M \times {\bf Z}_N \times \tilde{D}_4$. The flavor symmetry controls the mass spectra of heavy particles as well as those of quarks and leptons in the intermediate energy region ranging from the string scale ($\sim 10^{18} {\rm GeV}$) to the electroweak scale. In this paper we examine the mass spectra of heavy particles in detail in our model. The renormalization group evolution of the gauge couplings is studied up to two-loop order. A consistent solution of the gauge unification around the string scale is found by adjusting the spectra of the anti-generation matter fields.
[ { "created": "Fri, 26 Sep 2003 07:12:25 GMT", "version": "v1" }, { "created": "Fri, 31 Oct 2003 02:32:25 GMT", "version": "v2" } ]
2009-11-10
[ [ "Hayashi", "Takemi", "" ], [ "Matsuda", "Masahisa", "" ], [ "Matsuoka", "Takeo", "" ] ]
We study the path from the string scale physics to the low-energy physics in the $SU(6) \times SU(2)_R$ string-inspired model with the flavor symmetry ${\bf Z}_M \times {\bf Z}_N \times \tilde{D}_4$. The flavor symmetry controls the mass spectra of heavy particles as well as those of quarks and leptons in the intermediate energy region ranging from the string scale ($\sim 10^{18} {\rm GeV}$) to the electroweak scale. In this paper we examine the mass spectra of heavy particles in detail in our model. The renormalization group evolution of the gauge couplings is studied up to two-loop order. A consistent solution of the gauge unification around the string scale is found by adjusting the spectra of the anti-generation matter fields.
hep-ph/9901335
Hubert Spiesberger
C.Diaconu, J.Kalinowski, T.Matsushita, H.Spiesberger and D.S.Waters
High P_T Leptons and W Production at HERA
9 pages, 6 figures, LaTeX, uses iop style files and axodraw.sty. To appear in the proceedings of the 3rd UK Phenomenology Workshop on HERA Physics, September 1998, Durham (J.Phys.G: Nucl.Part.Phys.)
J.Phys.G25:1412-1417,1999
10.1088/0954-3899/25/7/318
CPPM-P-1999-01 (Marseille), IFT/98-20 (Warsaw), OUNP-99-02 (Oxford), MZ-TH/99-01 (Mainz)
hep-ph
null
Details are given of the observation by H1 of events containing high P_T leptons in addition to large missing P_T. A closely related ZEUS analysis, including a preliminary measurement of the W production cross section, is discussed and the two experiments are compared. Some possible non-Standard Model sources for the events are considered.
[ { "created": "Mon, 18 Jan 1999 09:58:39 GMT", "version": "v1" } ]
2008-11-26
[ [ "Diaconu", "C.", "" ], [ "Kalinowski", "J.", "" ], [ "Matsushita", "T.", "" ], [ "Spiesberger", "H.", "" ], [ "Waters", "D. S.", "" ] ]
Details are given of the observation by H1 of events containing high P_T leptons in addition to large missing P_T. A closely related ZEUS analysis, including a preliminary measurement of the W production cross section, is discussed and the two experiments are compared. Some possible non-Standard Model sources for the events are considered.
2305.12566
Bartosz Fornal
Bartosz Fornal, Kassandra Garcia, Erika Pierre
Testing Unification and Dark Matter with Gravitational Waves
10 pages, 8 figures
Phys. Rev. D 108, 055022 (2023)
10.1103/PhysRevD.108.055022
null
hep-ph gr-qc
http://creativecommons.org/licenses/by/4.0/
We propose to search for a new type of gravitational wave signature relevant for particle physics models with symmetries broken at vastly different energy scales. The spectrum contains a characteristic double-peak structure consisting of a sharp peak from domain walls and a smooth bump from a first order phase transition in the early Universe. We demonstrate how such a gravitational wave signal arises in a new theory unifying baryon number and color into an SU(4) gauge group broken at the multi-TeV scale, and with lepton number promoted to an SU(2) gauge symmetry broken at the multi-EeV scale. The model contains two types of dark matter particles, explains the observed domination of matter over antimatter in the Universe, and accommodates nonzero neutrino masses. We discuss how future gravitational wave experiments, such as LISA, Big Bang Observer, DECIGO, Einstein Telescope, and Cosmic Explorer, can be utilized to look for this novel signature.
[ { "created": "Sun, 21 May 2023 21:03:48 GMT", "version": "v1" } ]
2023-09-26
[ [ "Fornal", "Bartosz", "" ], [ "Garcia", "Kassandra", "" ], [ "Pierre", "Erika", "" ] ]
We propose to search for a new type of gravitational wave signature relevant for particle physics models with symmetries broken at vastly different energy scales. The spectrum contains a characteristic double-peak structure consisting of a sharp peak from domain walls and a smooth bump from a first order phase transition in the early Universe. We demonstrate how such a gravitational wave signal arises in a new theory unifying baryon number and color into an SU(4) gauge group broken at the multi-TeV scale, and with lepton number promoted to an SU(2) gauge symmetry broken at the multi-EeV scale. The model contains two types of dark matter particles, explains the observed domination of matter over antimatter in the Universe, and accommodates nonzero neutrino masses. We discuss how future gravitational wave experiments, such as LISA, Big Bang Observer, DECIGO, Einstein Telescope, and Cosmic Explorer, can be utilized to look for this novel signature.
hep-ph/0101294
Jaume Guasch
Santi Bejar, Jaume Guasch, Joan Sola
FCNC top quark decays beyond the Standard Model
17 pages, 7 figures. Invited talk presented by Joan Sola at the 5th International Symposium on Radiative Corrections (RADCOR 2000) Carmel CA, USA, 11-15 September, 2000
null
null
UAB-FT-506, KA-TP-1-2001
hep-ph
null
Flavor Changing Neutral Current decays of the top quark within the strict context of the Standard Model are known to be extremely rare. In fact, they are hopelessly undetectable at the Tevatron, LHC and LC in any of their scheduled upgradings. Therefore, if a few of these events eventually show up in the future we will have certainly discovered new physics. We argue that this could well be the case for the LHC and the LC both within the Minimal Supersymmetric Standard Model (MSSM) and in a general two-Higgs-doublet model (2HDM), especially if we look for FCNC top quark decays into Higgs bosons.
[ { "created": "Fri, 26 Jan 2001 09:58:02 GMT", "version": "v1" } ]
2007-05-23
[ [ "Bejar", "Santi", "" ], [ "Guasch", "Jaume", "" ], [ "Sola", "Joan", "" ] ]
Flavor Changing Neutral Current decays of the top quark within the strict context of the Standard Model are known to be extremely rare. In fact, they are hopelessly undetectable at the Tevatron, LHC and LC in any of their scheduled upgradings. Therefore, if a few of these events eventually show up in the future we will have certainly discovered new physics. We argue that this could well be the case for the LHC and the LC both within the Minimal Supersymmetric Standard Model (MSSM) and in a general two-Higgs-doublet model (2HDM), especially if we look for FCNC top quark decays into Higgs bosons.
hep-ph/0111079
Vladimir Yaryguine
V.Alferov, Y.Bordanovski, S.Klimov, V.Ilukin, V. Kuznetsov, O.Radin, A.Shalunov, A.Sytin, P.Vetrov, V.Yaryguine, V.Zapolsky, V. Zarucheisky (Institute for High Energy Physics, Protvino, Russia)
U-70 Proton Synchrotron Extracted Beam Lines Control System Modernization
3 pages, 2 figures, International Conference on Accelerator and Large Experimental Physics Control Systems San Jose, California, November 27-30, 2001
eConf C011127 (2001) WEAP026
null
WEAP026
hep-ph
null
A 70 GeV Proton Synchrotron Extracted Beam Lines Control System is described. About 130 Magnet Dipoles and Quadrupoles, 20 Correction Magnets, 50 Beam Collimators, BPM equipment spread over 1 Km have to be controlled. The old System was based on the PDP-11/40 and LSI-11 compatible computers and the MIL 1553 STD as a Field Bus. It successfully operated about 15 years. A new system includes home made Equipment Controllers based on I 8051 Processors, CAN Field Bus, FECs, Servers, Consoles connected by Ethernet. On the first stage of modernization PDPs and LSIs are replaced with PCs connected by Ethernet. Equipment controllers are being successfully tested in the Collimators and Corrector Magnets Controls during a run.
[ { "created": "Wed, 7 Nov 2001 16:39:12 GMT", "version": "v1" } ]
2007-05-23
[ [ "Alferov", "V.", "", "Institute for High Energy Physics, Protvino, Russia" ], [ "Bordanovski", "Y.", "", "Institute for High Energy Physics, Protvino, Russia" ], [ "Klimov", "S.", "", "Institute for High Energy Physics, Protvino, Russia" ], [ "Ilukin", "V.", "", "Institute for High Energy Physics, Protvino, Russia" ], [ "Kuznetsov", "V.", "", "Institute for High Energy Physics, Protvino, Russia" ], [ "Radin", "O.", "", "Institute for High Energy Physics, Protvino, Russia" ], [ "Shalunov", "A.", "", "Institute for High Energy Physics, Protvino, Russia" ], [ "Sytin", "A.", "", "Institute for High Energy Physics, Protvino, Russia" ], [ "Vetrov", "P.", "", "Institute for High Energy Physics, Protvino, Russia" ], [ "Yaryguine", "V.", "", "Institute for High Energy Physics, Protvino, Russia" ], [ "Zapolsky", "V.", "", "Institute for High Energy Physics, Protvino, Russia" ], [ "Zarucheisky", "V.", "", "Institute for High Energy Physics, Protvino, Russia" ] ]
A 70 GeV Proton Synchrotron Extracted Beam Lines Control System is described. About 130 Magnet Dipoles and Quadrupoles, 20 Correction Magnets, 50 Beam Collimators, BPM equipment spread over 1 Km have to be controlled. The old System was based on the PDP-11/40 and LSI-11 compatible computers and the MIL 1553 STD as a Field Bus. It successfully operated about 15 years. A new system includes home made Equipment Controllers based on I 8051 Processors, CAN Field Bus, FECs, Servers, Consoles connected by Ethernet. On the first stage of modernization PDPs and LSIs are replaced with PCs connected by Ethernet. Equipment controllers are being successfully tested in the Collimators and Corrector Magnets Controls during a run.
hep-ph/9905415
Masahiro Yamaguchi
Pran Nath, Youichi Yamada and Masahiro Yamaguchi
Probing the Nature of Compactification with Kaluza-Klein Excitations at the Large Hadron Collider
17 pages, 6 figures
Phys.Lett. B466 (1999) 100-106
10.1016/S0370-2693(99)01141-7
TU-565
hep-ph
null
It is shown that the nature of compactification of extra dimensions in theories of large radius compactification can be explored in several processes at the Large Hadron Collider (LHC). Specifically it is shown that the characteristics of the Kaluza-Klein (KK) excitations encode information on the nature of compactification, i.e., on the number of compactified dimensions as well as on the type of compactification, e.g., of the specific orbifold compactification. The most dramatic signals arise from the interference pattern involving the exchange of the Standard Model spin 1 bosons ($\gamma$ and Z) and their Kaluza-Klein modes in the dilepton final state $pp\to l^+l^-X$. It is shown that LHC with 100$fb^{-1}$ of luminosity can discover Kaluza-Klein modes up to compactification scales of $\approx 6$ TeV as well as identify the nature of compactification. Effects of the Kaluza-Klein excitations of the W boson and of the gluon are also studied. Exhibition of these phenomena is given for the case of one extra dimension and for the case of two extra dimensions with $Z_2\times Z_2, Z_3$, and $Z_6$ orbifold compactifications.
[ { "created": "Thu, 20 May 1999 08:57:35 GMT", "version": "v1" } ]
2009-10-31
[ [ "Nath", "Pran", "" ], [ "Yamada", "Youichi", "" ], [ "Yamaguchi", "Masahiro", "" ] ]
It is shown that the nature of compactification of extra dimensions in theories of large radius compactification can be explored in several processes at the Large Hadron Collider (LHC). Specifically it is shown that the characteristics of the Kaluza-Klein (KK) excitations encode information on the nature of compactification, i.e., on the number of compactified dimensions as well as on the type of compactification, e.g., of the specific orbifold compactification. The most dramatic signals arise from the interference pattern involving the exchange of the Standard Model spin 1 bosons ($\gamma$ and Z) and their Kaluza-Klein modes in the dilepton final state $pp\to l^+l^-X$. It is shown that LHC with 100$fb^{-1}$ of luminosity can discover Kaluza-Klein modes up to compactification scales of $\approx 6$ TeV as well as identify the nature of compactification. Effects of the Kaluza-Klein excitations of the W boson and of the gluon are also studied. Exhibition of these phenomena is given for the case of one extra dimension and for the case of two extra dimensions with $Z_2\times Z_2, Z_3$, and $Z_6$ orbifold compactifications.
hep-ph/9909571
Silas R. Beane
Silas R. Beane
High Energy Theorems at Large-N
34 pages TeX and mtexsis.tex, 10 figures (uses epsf)
J.Phys.G27:727-754,2001
10.1088/0954-3899/27/4/301
DOE/ER/40762-170, NT@UW-99-53
hep-ph
null
Sum rules for products of two, three and four QCD currents are derived using chiral symmetry at infinite momentum in the large-N limit. These exact relations among meson decay constants, axialvector couplings and masses determine the asymptotic behavior of an infinite number of QCD correlators. The familiar spectral function sum rules for products of two QCD currents are among the relations derived. With this precise knowledge of asymptotic behavior, an infinite number of large-N QCD correlators can be constructed using dispersion relations. A detailed derivation is given of the exact large-N pion vector form factor and forward pion-pion scattering amplitudes.
[ { "created": "Thu, 30 Sep 1999 16:56:22 GMT", "version": "v1" } ]
2008-11-26
[ [ "Beane", "Silas R.", "" ] ]
Sum rules for products of two, three and four QCD currents are derived using chiral symmetry at infinite momentum in the large-N limit. These exact relations among meson decay constants, axialvector couplings and masses determine the asymptotic behavior of an infinite number of QCD correlators. The familiar spectral function sum rules for products of two QCD currents are among the relations derived. With this precise knowledge of asymptotic behavior, an infinite number of large-N QCD correlators can be constructed using dispersion relations. A detailed derivation is given of the exact large-N pion vector form factor and forward pion-pion scattering amplitudes.
hep-ph/9505293
K. Milton
Kimball A. Milton
Julian Schwinger: Source Theory and the UCLA Years--- From Magnetic Charge to the Casimir Effect
15 pages, plain TeX, no figures, available through anonymous ftp from ftp://euclid.tp.ph.ic.ac.uk/papers/ or on WWW at http://euclid.tp.ph.ic.ac.uk/Papers/
null
10.1142/9789812830449_0018
OKHEP-95-05 and Imperial/TP/94-95/32
hep-ph hep-th
null
Julian Schwinger began the construction of Source Theory in 1966 in response to the then apparent failure of quantum field theory to describe strong interactions, the physical remoteness of renormalization, and the utility of effective actions in describing chiral dynamics. I will argue that the source theory development was not really so abrupt a break with the past as Julian may have implied, for the ideas and techniques in large measure were present in his work at least as early as 1951. Those techniques and ideas are still of fundamental importance to theoretical physics, so much so that the designation ``source theory'' has become superfluous. Julian did a great deal of innovative physics during the last 30 years of his life, and I will touch on some of the major themes. The impact of much of this work is not yet apparent. (Invited talk at Washington APS/AAPT meeting)
[ { "created": "Fri, 12 May 1995 15:02:13 GMT", "version": "v1" } ]
2016-11-03
[ [ "Milton", "Kimball A.", "" ] ]
Julian Schwinger began the construction of Source Theory in 1966 in response to the then apparent failure of quantum field theory to describe strong interactions, the physical remoteness of renormalization, and the utility of effective actions in describing chiral dynamics. I will argue that the source theory development was not really so abrupt a break with the past as Julian may have implied, for the ideas and techniques in large measure were present in his work at least as early as 1951. Those techniques and ideas are still of fundamental importance to theoretical physics, so much so that the designation ``source theory'' has become superfluous. Julian did a great deal of innovative physics during the last 30 years of his life, and I will touch on some of the major themes. The impact of much of this work is not yet apparent. (Invited talk at Washington APS/AAPT meeting)
2211.08420
Zhongtian Dong
Zhongtian Dong, Kyoungchul Kong, Konstantin T. Matchev, Katia Matcheva
Is the Machine Smarter than the Theorist: Deriving Formulas for Particle Kinematics with Symbolic Regression
15 pages, 13 figures, 8 tables
null
10.1103/PhysRevD.107.055018
null
hep-ph cs.AI cs.LG cs.SC hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We demonstrate the use of symbolic regression in deriving analytical formulas, which are needed at various stages of a typical experimental analysis in collider phenomenology. As a first application, we consider kinematic variables like the stransverse mass, $M_{T2}$, which are defined algorithmically through an optimization procedure and not in terms of an analytical formula. We then train a symbolic regression and obtain the correct analytical expressions for all known special cases of $M_{T2}$ in the literature. As a second application, we reproduce the correct analytical expression for a next-to-leading order (NLO) kinematic distribution from data, which is simulated with a NLO event generator. Finally, we derive analytical approximations for the NLO kinematic distributions after detector simulation, for which no known analytical formulas currently exist.
[ { "created": "Tue, 15 Nov 2022 18:57:59 GMT", "version": "v1" } ]
2023-03-29
[ [ "Dong", "Zhongtian", "" ], [ "Kong", "Kyoungchul", "" ], [ "Matchev", "Konstantin T.", "" ], [ "Matcheva", "Katia", "" ] ]
We demonstrate the use of symbolic regression in deriving analytical formulas, which are needed at various stages of a typical experimental analysis in collider phenomenology. As a first application, we consider kinematic variables like the stransverse mass, $M_{T2}$, which are defined algorithmically through an optimization procedure and not in terms of an analytical formula. We then train a symbolic regression and obtain the correct analytical expressions for all known special cases of $M_{T2}$ in the literature. As a second application, we reproduce the correct analytical expression for a next-to-leading order (NLO) kinematic distribution from data, which is simulated with a NLO event generator. Finally, we derive analytical approximations for the NLO kinematic distributions after detector simulation, for which no known analytical formulas currently exist.
2004.09485
Daniel Moreno Torres
Thomas Mannel, Daniel Moreno, and Alexei Pivovarov
Heavy Quark Expansion for Heavy Hadron Lifetimes: Completing the $1/m_b^3$ Corrections
26 pages and 3 figures
null
null
SI-HEP-2020-09 SFB-257-P3H-20-015
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We complete the calculation of the contributions from the dimension six operators in the heavy quark expansion for the total lifetime of heavy hadrons. We give the expressions for the Wilson coefficients of the Darwin term $\rho_D$ and the spin-orbit term $\rho_{\rm LS}$ at tree level.
[ { "created": "Mon, 20 Apr 2020 17:59:35 GMT", "version": "v1" }, { "created": "Thu, 9 Dec 2021 15:26:10 GMT", "version": "v2" }, { "created": "Mon, 17 Jun 2024 15:28:13 GMT", "version": "v3" } ]
2024-06-18
[ [ "Mannel", "Thomas", "" ], [ "Moreno", "Daniel", "" ], [ "Pivovarov", "Alexei", "" ] ]
We complete the calculation of the contributions from the dimension six operators in the heavy quark expansion for the total lifetime of heavy hadrons. We give the expressions for the Wilson coefficients of the Darwin term $\rho_D$ and the spin-orbit term $\rho_{\rm LS}$ at tree level.
2008.02209
Pedro Cavalcanti Malta
D. Kroff, P.C. Malta
Constraining hidden photons via atomic force microscope measurements and the Plimpton-Lawton experiment
11 pages, 8 figures; matches published version
Phys. Rev. D 102, 095015 (2020)
10.1103/PhysRevD.102.095015
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Modifications to electrodynamics from physics beyond the Standard Model can be tested to a high accuracy. Here we use two setups to place bounds on hidden photons, an Abelian boson kinetically mixed with the photon. The first setup involves atomic force microscope measurements, originally designed to study the Casimir effect at sub-$\mu$m distances. The second setup consists of two concentric metal shells with the outer one exposed to a high voltage. By measuring the potential difference between the shells it is possible to test Coulomb's law. The limits obtained here cover regions already excluded, in particular by astrophysical observations, but provide a more direct, laboratory-based confirmation of these bounds.
[ { "created": "Wed, 5 Aug 2020 16:25:06 GMT", "version": "v1" }, { "created": "Sun, 23 Aug 2020 19:00:33 GMT", "version": "v2" }, { "created": "Fri, 13 Nov 2020 18:56:32 GMT", "version": "v3" } ]
2020-11-16
[ [ "Kroff", "D.", "" ], [ "Malta", "P. C.", "" ] ]
Modifications to electrodynamics from physics beyond the Standard Model can be tested to a high accuracy. Here we use two setups to place bounds on hidden photons, an Abelian boson kinetically mixed with the photon. The first setup involves atomic force microscope measurements, originally designed to study the Casimir effect at sub-$\mu$m distances. The second setup consists of two concentric metal shells with the outer one exposed to a high voltage. By measuring the potential difference between the shells it is possible to test Coulomb's law. The limits obtained here cover regions already excluded, in particular by astrophysical observations, but provide a more direct, laboratory-based confirmation of these bounds.
hep-ph/0109192
Oleg G. Tkachev
V.A. Nikolaev, O.G. Tkachev
Skyrme Model Language in the Theory of Nucleons and Nuclei
15 pages, 8 figures
null
null
null
hep-ph
null
In this talk we try to clarify the problems existing on the way of theorist decided to construct nuclear theory on the generalized Skyrme model background. We conclude that to construct such a model of light nuclei one have to construct a hybrid model where one particle degrees of freedom are concentrated around the surface of the nuclei and soliton with non-trivial structure is located at the center region.
[ { "created": "Fri, 21 Sep 2001 00:14:05 GMT", "version": "v1" } ]
2007-05-23
[ [ "Nikolaev", "V. A.", "" ], [ "Tkachev", "O. G.", "" ] ]
In this talk we try to clarify the problems existing on the way of theorist decided to construct nuclear theory on the generalized Skyrme model background. We conclude that to construct such a model of light nuclei one have to construct a hybrid model where one particle degrees of freedom are concentrated around the surface of the nuclei and soliton with non-trivial structure is located at the center region.
hep-ph/9506427
Elizabeth H. Simmons
R.S. Chivukula, E.H. Simmons, and J. Terning
Limits on Non-Commuting Extended Technicolor
figures on hep-ph replaced with working versions! 20 pages, latex, 3 figures, figures also available at http://smyrd.bu.edu/htfigs/htfigs.html
Phys.Rev.D53:5258-5267,1996
10.1103/PhysRevD.53.5258
BUHEP-95-19
hep-ph
null
Using precision electroweak data, we put limits on non-commuting extended technicolor models. We conclude that these models are viable only if the ETC interactions are strong. Interestingly, these models predict a pattern of deviations from the standard model which can fit the data significantly better than the standard model does, even after taking into account the extra parameters involved.
[ { "created": "Mon, 26 Jun 1995 18:58:28 GMT", "version": "v1" }, { "created": "Wed, 28 Jun 1995 20:16:54 GMT", "version": "v2" } ]
2008-11-26
[ [ "Chivukula", "R. S.", "" ], [ "Simmons", "E. H.", "" ], [ "Terning", "J.", "" ] ]
Using precision electroweak data, we put limits on non-commuting extended technicolor models. We conclude that these models are viable only if the ETC interactions are strong. Interestingly, these models predict a pattern of deviations from the standard model which can fit the data significantly better than the standard model does, even after taking into account the extra parameters involved.
hep-ph/0612330
Hisakazu Minakata
Kunio Inoue, Hisakazu Minakata
Neutrino Physics around MeV Energies
6 pages, 2 figures, Conveners' report for NOW2006 Proceedings
Nucl.Phys.Proc.Suppl.168:389-394,2007
10.1016/j.nuclphysbps.2007.02.095
null
hep-ph hep-ex
null
We present a brief informative overview of a broad ranges of subjects, the solar, the reactor, the geo and the supernova neutrinos (but without excluding possible biases), the topics which consist of the session ``Neutrino Physics around MeV Energies'' in NOW2006. Contrary to the naive expectation, the field is found to be very active in improving the performance of existing detectors, and in preparation for the development coming in the near future. The former includes excellent performance of SNO 3He detector, successful reconstruction of SK III, and KamLAND's new ``4pi'' calibration. The next data release from these experiments will be very exciting. The latter includes effort for lowering threshold in SK III, KamLAND's purification by which geo-neutrino observation becomes much cleaner, and the forthcoming 7Be neutrino measurement by BOREXINO and KamLAND. Possible detection of relic supernova neutrinos and non-zero effect of theta_{13} would bring us great excitement. Furthermore, improved new measurement of heavy element abundance in the solar atmosphere resulted in a solar model with much lower CNO \nu flux and with disagreement with helioseismology, thereby bringing us a new solar puzzle.
[ { "created": "Mon, 25 Dec 2006 13:58:24 GMT", "version": "v1" } ]
2008-11-26
[ [ "Inoue", "Kunio", "" ], [ "Minakata", "Hisakazu", "" ] ]
We present a brief informative overview of a broad ranges of subjects, the solar, the reactor, the geo and the supernova neutrinos (but without excluding possible biases), the topics which consist of the session ``Neutrino Physics around MeV Energies'' in NOW2006. Contrary to the naive expectation, the field is found to be very active in improving the performance of existing detectors, and in preparation for the development coming in the near future. The former includes excellent performance of SNO 3He detector, successful reconstruction of SK III, and KamLAND's new ``4pi'' calibration. The next data release from these experiments will be very exciting. The latter includes effort for lowering threshold in SK III, KamLAND's purification by which geo-neutrino observation becomes much cleaner, and the forthcoming 7Be neutrino measurement by BOREXINO and KamLAND. Possible detection of relic supernova neutrinos and non-zero effect of theta_{13} would bring us great excitement. Furthermore, improved new measurement of heavy element abundance in the solar atmosphere resulted in a solar model with much lower CNO \nu flux and with disagreement with helioseismology, thereby bringing us a new solar puzzle.
2106.00681
Robert Ehrlich
Robert Ehrlich
The KATRIN neutrino mass results: An alternative interpretation
arXiv admin note: text overlap with arXiv:2101.08128
null
null
null
hep-ph
http://creativecommons.org/publicdomain/zero/1.0/
The KATRIN experiment has recently reported a new upper limit to the mass of the electron neutrino of $m<0.8 eV$ (90\%CL), and a best value of $m^2= 0.26 \pm 0.34 eV^2/c^4$ based on a fit to the observed tritium beta decay spectrum. Here another interpretation of their results is discussed.
[ { "created": "Tue, 1 Jun 2021 13:15:09 GMT", "version": "v1" }, { "created": "Mon, 2 Aug 2021 17:07:20 GMT", "version": "v2" }, { "created": "Wed, 1 Sep 2021 20:42:36 GMT", "version": "v3" }, { "created": "Sun, 21 Nov 2021 19:22:17 GMT", "version": "v4" } ]
2021-11-23
[ [ "Ehrlich", "Robert", "" ] ]
The KATRIN experiment has recently reported a new upper limit to the mass of the electron neutrino of $m<0.8 eV$ (90\%CL), and a best value of $m^2= 0.26 \pm 0.34 eV^2/c^4$ based on a fit to the observed tritium beta decay spectrum. Here another interpretation of their results is discussed.
hep-ph/0111362
Yuri V. Kovchegov
Yuri V. Kovchegov, Kirill Tuchin (University of Washington)
Inclusive Gluon Production in DIS at High Parton Density
22 pages, 7 figures, REVTeX
Phys.Rev. D65 (2002) 074026
10.1103/PhysRevD.65.074026
NT@UW-01-027, INT-PUB-01-25
hep-ph nucl-th
null
We calculate the cross section of a single inclusive gluon production in deep inelastic scattering at very high energies in the saturation regime, where the parton densities inside hadrons and nuclei are large and the evolution of structure functions with energy is nonlinear. The expression we obtain for the inclusive gluon production cross section is generated by this nonlinear evolution. We analyze the rapidity distribution of the produced gluons as well as their transverse momentum spectrum given by the derived expression for the inclusive cross section. We propose an ansatz for the multiplicity distribution of gluons produced in nuclear collisions which includes the effects of nonlinear evolution in both colliding nuclei.
[ { "created": "Wed, 28 Nov 2001 03:53:49 GMT", "version": "v1" } ]
2009-11-07
[ [ "Kovchegov", "Yuri V.", "", "University of Washington" ], [ "Tuchin", "Kirill", "", "University of Washington" ] ]
We calculate the cross section of a single inclusive gluon production in deep inelastic scattering at very high energies in the saturation regime, where the parton densities inside hadrons and nuclei are large and the evolution of structure functions with energy is nonlinear. The expression we obtain for the inclusive gluon production cross section is generated by this nonlinear evolution. We analyze the rapidity distribution of the produced gluons as well as their transverse momentum spectrum given by the derived expression for the inclusive cross section. We propose an ansatz for the multiplicity distribution of gluons produced in nuclear collisions which includes the effects of nonlinear evolution in both colliding nuclei.
2211.10249
Wei-Jie Fu
Yang-yang Tan and Chuang Huang and Yong-rui Chen and Wei-jie Fu
Criticality of the $O(N)$ universality via global solutions to nonperturbative fixed-point equations
10 pages, 4 figures, 1 table; v2: minor changes, discussions and references added
null
null
null
hep-ph hep-th
http://creativecommons.org/licenses/by/4.0/
Fixed-point equations in the functional renormalization group approach are integrated from large to vanishing field, where an asymptotic potential in the limit of large field is implemented as initial conditions. This approach allows us to obtain a global fixed-point potential with high numerical accuracy, that incorporates the correct asymptotic behavior in the limit of large field. Our calculated global potential is in good agreement with the Taylor expansion in the region of small field, and it also coincides with the Laurent expansion in the regime of large field. Laurent expansion of the potential in the limit of large field for general case, that the spatial dimension $d$ is a continuous variable in the range $2\leq d \leq 4$, is obtained. Eigenfunctions and eigenvalues of perturbations near the Wilson-Fisher fixed point are computed with the method of eigenperturbations. Critical exponents for different values of $d$ and $N$ of the $O(N)$ universality class are calculated.
[ { "created": "Fri, 18 Nov 2022 14:10:20 GMT", "version": "v1" }, { "created": "Sat, 8 Apr 2023 03:02:20 GMT", "version": "v2" } ]
2023-04-11
[ [ "Tan", "Yang-yang", "" ], [ "Huang", "Chuang", "" ], [ "Chen", "Yong-rui", "" ], [ "Fu", "Wei-jie", "" ] ]
Fixed-point equations in the functional renormalization group approach are integrated from large to vanishing field, where an asymptotic potential in the limit of large field is implemented as initial conditions. This approach allows us to obtain a global fixed-point potential with high numerical accuracy, that incorporates the correct asymptotic behavior in the limit of large field. Our calculated global potential is in good agreement with the Taylor expansion in the region of small field, and it also coincides with the Laurent expansion in the regime of large field. Laurent expansion of the potential in the limit of large field for general case, that the spatial dimension $d$ is a continuous variable in the range $2\leq d \leq 4$, is obtained. Eigenfunctions and eigenvalues of perturbations near the Wilson-Fisher fixed point are computed with the method of eigenperturbations. Critical exponents for different values of $d$ and $N$ of the $O(N)$ universality class are calculated.
hep-ph/9803442
Floarea Stancu
Fl. Stancu (U. of Liege)
Positive parity pentaquarks in a Goldstone boson exchange model
13 pages, RevTeX
Phys.Rev.D58:111501,1998
10.1103/PhysRevD.58.111501
ULG-PNT-98-1-J
hep-ph
null
We study the stability of the pentaquarks uuddQbar, uudsQbar and udssQbar (Q = c, b, or t) of positive parity in a constituent quark model based on Goldstone boson exchange interaction between quarks. The pentaquark parity is the antiquark parity times that of a quark excited to a p-shell. We show that the Goldstone boson exchange interaction favors these pentaquarks much more than the negative parity ones of the same flavour content but all quarks in the ground state. We find that the nonstrange pentaquarks are stable against strong decays.
[ { "created": "Wed, 25 Mar 1998 10:21:59 GMT", "version": "v1" } ]
2009-12-30
[ [ "Stancu", "Fl.", "", "U. of Liege" ] ]
We study the stability of the pentaquarks uuddQbar, uudsQbar and udssQbar (Q = c, b, or t) of positive parity in a constituent quark model based on Goldstone boson exchange interaction between quarks. The pentaquark parity is the antiquark parity times that of a quark excited to a p-shell. We show that the Goldstone boson exchange interaction favors these pentaquarks much more than the negative parity ones of the same flavour content but all quarks in the ground state. We find that the nonstrange pentaquarks are stable against strong decays.
hep-ph/0007025
Juan Antonio Aguilar Saavedra
J. A. Aguilar-Saavedra, G. C. Branco
Unitarity triangles and geometrical description of CP violation with Majorana neutrinos
Revtex, 6 pages, 5 eps figures. Some typos fixed and a reference added. To appear in PRD
Phys.Rev. D62 (2000) 096009
10.1103/PhysRevD.62.096009
UG-FT-117/00
hep-ph
null
We generalize the geometrical description of CP violation in the Standard Model in terms of a unitarity triangle. For three left-handed Majorana neutrinos CP violation in the lepton sector is determined by three unitarity triangles. With three additional right-handed neutrinos 15 quadrangles are required to characterize CP violation. We show the relation of the unitarity polygons with physical observables.
[ { "created": "Tue, 4 Jul 2000 09:47:34 GMT", "version": "v1" }, { "created": "Mon, 7 Aug 2000 10:28:16 GMT", "version": "v2" } ]
2009-10-31
[ [ "Aguilar-Saavedra", "J. A.", "" ], [ "Branco", "G. C.", "" ] ]
We generalize the geometrical description of CP violation in the Standard Model in terms of a unitarity triangle. For three left-handed Majorana neutrinos CP violation in the lepton sector is determined by three unitarity triangles. With three additional right-handed neutrinos 15 quadrangles are required to characterize CP violation. We show the relation of the unitarity polygons with physical observables.
hep-ph/0511012
Denis A. Suprun
Amarjit Soni and Denis A. Suprun
Determination of gamma from charmless B^+/- -> M^0 M^+/- decays using U-spin
5 pages; minor changes, further clarification on key differences with the SU(3) approach; added references
Phys.Lett.B635:330-334,2006
10.1016/j.physletb.2006.02.063
null
hep-ph
null
U-spin multiplet approach is applied to the full set of charmless hadronic B+/- --> M0 M+/- decays for the purpose of precise extraction of the unitarity angle gamma. Each of the four data sets, P0 P+/-, P0 V+/-, V0 P+/- and V0 V+/-, with P = pseudoscalar and V = vector, can be used to yield a precise value of gamma. The crucial advantage of this method over the common SU(3) symmetry based quark-diagrammatic approach is that no assumptions regarding relative sizes of topological decay amplitudes need to be made. As a result, this method avoids an uncontrollable theoretical uncertainty that is related to the neglect of some topological diagrams (e.g., exchange and annihilation graphs) in the SU(3) approach. Application of the U-spin approach to the current data yields: gamma=54^{+12}_{-11} degrees. We find that improved measurements of phi pi+/- and K*0bar K+/- branching ratios would lead to appreciably better extraction of gamma. In this method, which is completely data driven, in a few years we should be able to obtain a model independent determination of gamma with an accuracy of O(few degrees).
[ { "created": "Wed, 2 Nov 2005 20:20:35 GMT", "version": "v1" }, { "created": "Mon, 14 Nov 2005 19:57:20 GMT", "version": "v2" }, { "created": "Fri, 27 Jan 2006 20:25:53 GMT", "version": "v3" }, { "created": "Sat, 28 Jan 2006 21:58:12 GMT", "version": "v4" } ]
2010-11-05
[ [ "Soni", "Amarjit", "" ], [ "Suprun", "Denis A.", "" ] ]
U-spin multiplet approach is applied to the full set of charmless hadronic B+/- --> M0 M+/- decays for the purpose of precise extraction of the unitarity angle gamma. Each of the four data sets, P0 P+/-, P0 V+/-, V0 P+/- and V0 V+/-, with P = pseudoscalar and V = vector, can be used to yield a precise value of gamma. The crucial advantage of this method over the common SU(3) symmetry based quark-diagrammatic approach is that no assumptions regarding relative sizes of topological decay amplitudes need to be made. As a result, this method avoids an uncontrollable theoretical uncertainty that is related to the neglect of some topological diagrams (e.g., exchange and annihilation graphs) in the SU(3) approach. Application of the U-spin approach to the current data yields: gamma=54^{+12}_{-11} degrees. We find that improved measurements of phi pi+/- and K*0bar K+/- branching ratios would lead to appreciably better extraction of gamma. In this method, which is completely data driven, in a few years we should be able to obtain a model independent determination of gamma with an accuracy of O(few degrees).
hep-ph/9709378
Ramon Miquel
Ramon Miquel (Univ. de Barcelona)
New Physics at LEP2
LaTeX, 15 pages, 7 eps figures, needs iopconf1.sty, included. To appear in the proceedings of "Beyond the Desert", Castle Ringberg, Tegernsee, Germany, 8-14 June 1997
null
null
null
hep-ph hep-ex
null
Searches for new physics in the first year of running of LEP2, at energies of 161 and 172 GeV, are summarized. After a short review of WW results and their implications on new physics, searches for the Higgs boson and SUSY particles, analyses of four-jet final states and constraints on possible explanations for the HERA high Q**2 anomaly are discussed in turn.
[ { "created": "Wed, 17 Sep 1997 14:38:58 GMT", "version": "v1" } ]
2007-05-23
[ [ "Miquel", "Ramon", "", "Univ. de Barcelona" ] ]
Searches for new physics in the first year of running of LEP2, at energies of 161 and 172 GeV, are summarized. After a short review of WW results and their implications on new physics, searches for the Higgs boson and SUSY particles, analyses of four-jet final states and constraints on possible explanations for the HERA high Q**2 anomaly are discussed in turn.
1311.0921
Nobuchika Okada
Nobuchika Okada, Qaisar Shafi
Observable Gravity Waves From U(1)_${B-L}$ Higgs and Coleman-Weinberg Inflation
4 pages, 4 figures
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a realistic non-supersymmetric inflation model based on a gauged U(1)$_{B-L}$ symmetry and a tree-level Higgs potential. The inflaton is identified with the scalar field which spontaneously breaks U(1)$_{B-L}$, and we include radiative corrections \`a la Coleman-Weinberg in the inflaton potential. If the scalar spectral index $n_s$ lies close to 0.96, as indicated by the recent Planck and WMAP 9-yr measurements, the tensor-to-scalar ratio $r$, a canonical measure for gravity waves, exceeds 0.01. Thus, according to this model, gravity waves should be found in the near future. In this case, the quantity $|dn_s/d \ln k|$ lies in the range $0.004-0.005$. Successful baryogenesis can be realized in this class of models either via thermal or non-thermal leptogenesis.
[ { "created": "Mon, 4 Nov 2013 23:04:30 GMT", "version": "v1" } ]
2013-11-06
[ [ "Okada", "Nobuchika", "" ], [ "Shafi", "Qaisar", "" ] ]
We present a realistic non-supersymmetric inflation model based on a gauged U(1)$_{B-L}$ symmetry and a tree-level Higgs potential. The inflaton is identified with the scalar field which spontaneously breaks U(1)$_{B-L}$, and we include radiative corrections \`a la Coleman-Weinberg in the inflaton potential. If the scalar spectral index $n_s$ lies close to 0.96, as indicated by the recent Planck and WMAP 9-yr measurements, the tensor-to-scalar ratio $r$, a canonical measure for gravity waves, exceeds 0.01. Thus, according to this model, gravity waves should be found in the near future. In this case, the quantity $|dn_s/d \ln k|$ lies in the range $0.004-0.005$. Successful baryogenesis can be realized in this class of models either via thermal or non-thermal leptogenesis.
2405.15386
Stefan Diehl
Stefan Diehl, Kyungseon Joo, Kirill Semenov-Tian-Shansky, Christian Weiss, Vladimir Braun, Wen-Chen Chang, Pierre Chatagnon, Martha Constantinou, Yuxun Guo, Parada T. P. Hutauruk, Hyon-Suk Jo, Andrey Kim, Jun-Young Kim, Peter Kroll, Shunzo Kumano, Chang-Hwan Lee, Simonetta Liuti, Ronan McNulty, Hyeon-Dong Son, Pawel Sznajder, Ali Usman, Charlotte Van Hulse, Marc Vanderhaeghen and Michael Winn
Exploring Baryon Resonances with Transition Generalized Parton Distributions: Status and Perspectives
null
null
null
JLAB-THY-24-4071
hep-ph hep-ex nucl-th
http://creativecommons.org/licenses/by/4.0/
QCD gives rise to a rich spectrum of excited baryon states. Understanding their internal structure is important for many areas of nuclear physics, such as nuclear forces, dense matter, and neutrino-nucleus interactions. Generalized parton distributions (GPDs) are an established tool for characterizing the QCD structure of the ground-state nucleon. They are used to create 3D tomographic images of the quark/gluon structure and quantify the mechanical properties such as the distribution of mass, angular momentum and forces in the system. Transition GPDs extend these concepts to $N \rightarrow N^\ast$ transitions and can be used to characterize the 3D structure and mechanical properties of baryon resonances. They can be probed in high-momentum-transfer exclusive electroproduction processes with resonance transitions $e + N \rightarrow e' + M + N^\ast$, such as deeply-virtual Compton scattering ($M = \gamma$) or meson production ($M = \pi, K$, $etc.$), and in related photon/hadron-induced processes. This White Paper describes a research program aiming to explore baryon resonance structure with transition GPDs. This includes the properties and interpretation of the transition GPDs, theoretical methods for structures and processes, first experimental results from JLab 12 GeV, future measurements with existing and planned facilities (JLab detector and energy upgrades, COMPASS/AMBER, EIC, EicC, J-PARC, LHC ultraperihperal collisions), and the theoretical and experimental developments needed to realize this program.
[ { "created": "Fri, 24 May 2024 09:36:03 GMT", "version": "v1" } ]
2024-05-27
[ [ "Diehl", "Stefan", "" ], [ "Joo", "Kyungseon", "" ], [ "Semenov-Tian-Shansky", "Kirill", "" ], [ "Weiss", "Christian", "" ], [ "Braun", "Vladimir", "" ], [ "Chang", "Wen-Chen", "" ], [ "Chatagnon", "Pierre", "" ], [ "Constantinou", "Martha", "" ], [ "Guo", "Yuxun", "" ], [ "Hutauruk", "Parada T. P.", "" ], [ "Jo", "Hyon-Suk", "" ], [ "Kim", "Andrey", "" ], [ "Kim", "Jun-Young", "" ], [ "Kroll", "Peter", "" ], [ "Kumano", "Shunzo", "" ], [ "Lee", "Chang-Hwan", "" ], [ "Liuti", "Simonetta", "" ], [ "McNulty", "Ronan", "" ], [ "Son", "Hyeon-Dong", "" ], [ "Sznajder", "Pawel", "" ], [ "Usman", "Ali", "" ], [ "Van Hulse", "Charlotte", "" ], [ "Vanderhaeghen", "Marc", "" ], [ "Winn", "Michael", "" ] ]
QCD gives rise to a rich spectrum of excited baryon states. Understanding their internal structure is important for many areas of nuclear physics, such as nuclear forces, dense matter, and neutrino-nucleus interactions. Generalized parton distributions (GPDs) are an established tool for characterizing the QCD structure of the ground-state nucleon. They are used to create 3D tomographic images of the quark/gluon structure and quantify the mechanical properties such as the distribution of mass, angular momentum and forces in the system. Transition GPDs extend these concepts to $N \rightarrow N^\ast$ transitions and can be used to characterize the 3D structure and mechanical properties of baryon resonances. They can be probed in high-momentum-transfer exclusive electroproduction processes with resonance transitions $e + N \rightarrow e' + M + N^\ast$, such as deeply-virtual Compton scattering ($M = \gamma$) or meson production ($M = \pi, K$, $etc.$), and in related photon/hadron-induced processes. This White Paper describes a research program aiming to explore baryon resonance structure with transition GPDs. This includes the properties and interpretation of the transition GPDs, theoretical methods for structures and processes, first experimental results from JLab 12 GeV, future measurements with existing and planned facilities (JLab detector and energy upgrades, COMPASS/AMBER, EIC, EicC, J-PARC, LHC ultraperihperal collisions), and the theoretical and experimental developments needed to realize this program.
0910.5395
Anton Ilderton
Anton Ilderton, Martin Lavelle, David McMullan
Physical charges in QED and QCD
Talk given at the International Workshop on QCD Green's Functions, Confinement and Phenomenology, September 7-11 2009, ECT Trento, Italy. 8 pages, 3 pdf figures. V2: references added, to appear in PoS
PoS QCD-TNT09:019,2009
null
TCDMATH 09-23
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We show that the `dressing' approach, which describes physical charges as gauge invariant composites of matter and clouds of gauge bosons, arises naturally in gauge theories. We give perturbative examples of dressings for both asymptotic charges and for states in which the fields are confined to a compact volume as is required, for example, by causality in pair creation. In QCD, we use dressed states to demonstrate explicitly how Gribov copies obstruct the non-perturbative construction of colour charges.
[ { "created": "Wed, 28 Oct 2009 14:49:27 GMT", "version": "v1" }, { "created": "Fri, 4 Dec 2009 08:28:48 GMT", "version": "v2" } ]
2014-11-20
[ [ "Ilderton", "Anton", "" ], [ "Lavelle", "Martin", "" ], [ "McMullan", "David", "" ] ]
We show that the `dressing' approach, which describes physical charges as gauge invariant composites of matter and clouds of gauge bosons, arises naturally in gauge theories. We give perturbative examples of dressings for both asymptotic charges and for states in which the fields are confined to a compact volume as is required, for example, by causality in pair creation. In QCD, we use dressed states to demonstrate explicitly how Gribov copies obstruct the non-perturbative construction of colour charges.
hep-ph/9609263
null
Stefano Catani (INFN Firenze)
Physical Anomalous Dimensions at Small $x$
26 pages, LateX
Z.Phys.C75:665-678,1997
10.1007/s002880050512
DFF 248/4/96
hep-ph
null
I present a theoretical discussion of the uncertainties related to the QCD analysis of the proton structure function $F_2(x,Q^2)$ at small $x$. The role played by the `unphysical' gluon density is pointed out. It is shown how the study of more observables can reduce the theoretical uncertainty and, in particular, an alternative method of analysis, based on the introduction of physical anomalous dimensions, is suggested.
[ { "created": "Thu, 5 Sep 1996 13:23:19 GMT", "version": "v1" } ]
2008-11-26
[ [ "Catani", "Stefano", "", "INFN Firenze" ] ]
I present a theoretical discussion of the uncertainties related to the QCD analysis of the proton structure function $F_2(x,Q^2)$ at small $x$. The role played by the `unphysical' gluon density is pointed out. It is shown how the study of more observables can reduce the theoretical uncertainty and, in particular, an alternative method of analysis, based on the introduction of physical anomalous dimensions, is suggested.
hep-ph/9412348
null
S. Frixione, M. L. Mangano, P. Nason and G. Ridolfi
Total Cross Sections for Heavy Flavour Production at HERA
20 pages, Latex and style files tarred, gzipped and uuencoded; 10 postscript figures appended at the end (look for %%%%figures) as tarred, gzipped and uuencoded file
Phys.Lett.B348:633-645,1995
10.1016/0370-2693(95)00163-F
CERN-TH.7527/94, GEF-TH-9/1994, IFUM 487/FT
hep-ph
null
We compute total cross sections for charm and bottom photoproduction at HERA energies, and discuss the relevant theoretical uncertainties. In particular we discuss the problems arising from the small-$x$ region, the uncertainties in the gluon parton density, and the uncertainties in the hadronic component of the cross section. Total electroproduction cross sections, calculated in the Weizs\"acker-Williams approximation, are also given.
[ { "created": "Wed, 21 Dec 1994 16:07:32 GMT", "version": "v1" } ]
2008-11-26
[ [ "Frixione", "S.", "" ], [ "Mangano", "M. L.", "" ], [ "Nason", "P.", "" ], [ "Ridolfi", "G.", "" ] ]
We compute total cross sections for charm and bottom photoproduction at HERA energies, and discuss the relevant theoretical uncertainties. In particular we discuss the problems arising from the small-$x$ region, the uncertainties in the gluon parton density, and the uncertainties in the hadronic component of the cross section. Total electroproduction cross sections, calculated in the Weizs\"acker-Williams approximation, are also given.
2408.04255
Hee Sok Chung
Hee Sok Chung, U-Rae Kim, Jungil Lee
Resummation of threshold double logarithms in hadroproduction of heavy quarkonium
6 pages, 2 figures
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We resum threshold double logarithms that appear in inclusive production of heavy quarkonium. This resolves the catastrophic failure of fixed-order perturbation theory where quarkonium cross sections at large transverse momentum can turn negative due to large radiative corrections. We find that resummation is imperative for describing measured prompt production rates of $J/\psi$ at large transverse momentum.
[ { "created": "Thu, 8 Aug 2024 06:48:29 GMT", "version": "v1" } ]
2024-08-09
[ [ "Chung", "Hee Sok", "" ], [ "Kim", "U-Rae", "" ], [ "Lee", "Jungil", "" ] ]
We resum threshold double logarithms that appear in inclusive production of heavy quarkonium. This resolves the catastrophic failure of fixed-order perturbation theory where quarkonium cross sections at large transverse momentum can turn negative due to large radiative corrections. We find that resummation is imperative for describing measured prompt production rates of $J/\psi$ at large transverse momentum.
1601.00799
Igor Lokhtin P.
I.P. Lokhtin, A.V. Belyaev, G.Kh. Eyyubova, G. Ponimatkin, E.Yu. Pronina
Charmed meson and charmonium production in PbPb collisions at the LHC
15 pages including 8 figures as EPS-files; prepared using LaTeX package for publication in the Journal of Physics G
J.Phys. G: Nucl. Part. Phys. 43 (2016) 125104
10.1088/0954-3899/43/12/125104
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The phenomenological analysis of various characteristics of $J/\psi$ and $D$ meson production in PbPb collisions at the center-of-mass energy 2.76 TeV per nucleon pair is presented. The data on momentum spectra and elliptic flow are reproduced by two-component model HYDJET++ including thermal and non-thermal charm production mechanisms. The significant part of $D$-mesons is found to be in a kinetic equilibrium with the created medium, while $J/\psi$-mesons are characterized by earlier (as compared to light hadrons) freeze-out.
[ { "created": "Tue, 5 Jan 2016 11:42:17 GMT", "version": "v1" }, { "created": "Sun, 1 May 2016 09:49:25 GMT", "version": "v2" }, { "created": "Tue, 20 Sep 2016 11:31:40 GMT", "version": "v3" }, { "created": "Wed, 5 Oct 2016 18:04:44 GMT", "version": "v4" } ]
2016-11-11
[ [ "Lokhtin", "I. P.", "" ], [ "Belyaev", "A. V.", "" ], [ "Eyyubova", "G. Kh.", "" ], [ "Ponimatkin", "G.", "" ], [ "Pronina", "E. Yu.", "" ] ]
The phenomenological analysis of various characteristics of $J/\psi$ and $D$ meson production in PbPb collisions at the center-of-mass energy 2.76 TeV per nucleon pair is presented. The data on momentum spectra and elliptic flow are reproduced by two-component model HYDJET++ including thermal and non-thermal charm production mechanisms. The significant part of $D$-mesons is found to be in a kinetic equilibrium with the created medium, while $J/\psi$-mesons are characterized by earlier (as compared to light hadrons) freeze-out.
1304.7080
Kunihiko Terasaki
Kunihiko Terasaki
Decay Property of Axial-Vector Tetra-Quark Mesons
6 pages, 0 figures, typos corrected, description clarified
null
null
YITP-13-31
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Decay property of hidden-charm tetra-quark mesons is studied. It is seen that estimated width of iso-triplet odd $\mathcal{C}$ partners of X(3872), although still crude, is compatible with the measured ones of Z_c(3900). It is pointed out that confirmation of an eta-pi^0 peak around 3.2 GeV indicated in gamma-gamma collisions gives a clue to select a realistic model of multi-quark mesons.
[ { "created": "Fri, 26 Apr 2013 07:32:38 GMT", "version": "v1" }, { "created": "Fri, 11 Oct 2013 06:44:49 GMT", "version": "v2" }, { "created": "Tue, 15 Oct 2013 01:31:59 GMT", "version": "v3" }, { "created": "Wed, 16 Oct 2013 04:31:27 GMT", "version": "v4" }, { "created": "Thu, 7 Nov 2013 04:40:23 GMT", "version": "v5" } ]
2013-11-08
[ [ "Terasaki", "Kunihiko", "" ] ]
Decay property of hidden-charm tetra-quark mesons is studied. It is seen that estimated width of iso-triplet odd $\mathcal{C}$ partners of X(3872), although still crude, is compatible with the measured ones of Z_c(3900). It is pointed out that confirmation of an eta-pi^0 peak around 3.2 GeV indicated in gamma-gamma collisions gives a clue to select a realistic model of multi-quark mesons.
2011.12285
Wen Yin
Takeo Moroi and Wen Yin
Particle Production from Oscillating Scalar Field and Consistency of Boltzmann Equation
21 pages, 5 figures, 2 tables, version to appear in JHEP
null
null
null
hep-ph astro-ph.CO gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Boltzmann equation plays important roles in particle cosmology in studying the evolution of distribution functions (also called as occupation numbers) of various particles. For the case of the decay of a scalar condensation $\phi$ into a pair of scalar particles (called $\chi$), we point out that the system may not be well described by the Boltzmann equation when the occupation number of $\chi$ becomes large even in the so-called narrow resonance regime. We study the particle production including the possible enhancement due to a large occupation number of the final state particle, known as the stimulated emission or the parametric resonance. Based on the quantum field theory (QFT), we derive a set of equations which directly govern the evolution of the distribution function of $\chi$. Comparing the results of the QFT calculation and those from the Boltzmann equation, we find non-agreements in some cases. In particular, in the expanding Universe, the occupation number of $\chi$ based on the QFT may differ by many orders of magnitude from that from the Boltzmann equation. We also discuss a possible relation between the evolution equations based on the QFT and the Boltzmann equation.
[ { "created": "Tue, 24 Nov 2020 18:55:04 GMT", "version": "v1" }, { "created": "Tue, 30 Mar 2021 10:06:19 GMT", "version": "v2" } ]
2021-03-31
[ [ "Moroi", "Takeo", "" ], [ "Yin", "Wen", "" ] ]
Boltzmann equation plays important roles in particle cosmology in studying the evolution of distribution functions (also called as occupation numbers) of various particles. For the case of the decay of a scalar condensation $\phi$ into a pair of scalar particles (called $\chi$), we point out that the system may not be well described by the Boltzmann equation when the occupation number of $\chi$ becomes large even in the so-called narrow resonance regime. We study the particle production including the possible enhancement due to a large occupation number of the final state particle, known as the stimulated emission or the parametric resonance. Based on the quantum field theory (QFT), we derive a set of equations which directly govern the evolution of the distribution function of $\chi$. Comparing the results of the QFT calculation and those from the Boltzmann equation, we find non-agreements in some cases. In particular, in the expanding Universe, the occupation number of $\chi$ based on the QFT may differ by many orders of magnitude from that from the Boltzmann equation. We also discuss a possible relation between the evolution equations based on the QFT and the Boltzmann equation.
hep-ph/9702425
Naoto Tsutsui
Michihiro Hirata, Naoto Tsutsui
Phenomenological interaction between current quarks
18 pages, LaTeX
Phys.Rev. D56 (1997) 5696-5702
10.1103/PhysRevD.56.5696
HUPD-9703
hep-ph
null
We construct a phenomenological model which describes the dynamical chiral symmetry breaking (DCSB) of QCD vacuum and reproduces meson spectra. Quark condensates, the pion decay constant, and meson spectra are well reproduced by phenomenological interaction which consists of a linear confining potential, a Coulombic potential, and the 't Hooft determinant interaction. In this model, the 't Hooft determinant interaction plays a important role not to only \eta,\eta' mass difference, but other meson masses through DCSB.
[ { "created": "Wed, 26 Feb 1997 13:24:11 GMT", "version": "v1" } ]
2009-10-30
[ [ "Hirata", "Michihiro", "" ], [ "Tsutsui", "Naoto", "" ] ]
We construct a phenomenological model which describes the dynamical chiral symmetry breaking (DCSB) of QCD vacuum and reproduces meson spectra. Quark condensates, the pion decay constant, and meson spectra are well reproduced by phenomenological interaction which consists of a linear confining potential, a Coulombic potential, and the 't Hooft determinant interaction. In this model, the 't Hooft determinant interaction plays a important role not to only \eta,\eta' mass difference, but other meson masses through DCSB.
hep-ph/0110401
Ahmet T. Alan
A. T. Alan and S. Sultansoy
Production and Decay of Sneutrino and Squarks at Lepton-Hadron Colliders
6 pages, 1 eps figure, REVTEX4
Phys.Scripta 66 (2002) 20-21
10.1238/Physica.Regular.066a00020
null
hep-ph
null
We investigate the potentials of future high energy lepton-proton colliders to detect supersymmetric particles in the charged current type $lp\to\tilde\nu_l\tilde qX$, $l=e,\mu$, reactions. We also study their decays by using the mass spectrum given in the Technical Design Report of ATLAS Collaboration (SUGRA Point 6 corresponding to large $tan\beta$).
[ { "created": "Wed, 31 Oct 2001 12:28:46 GMT", "version": "v1" }, { "created": "Mon, 5 Nov 2001 14:10:47 GMT", "version": "v2" } ]
2009-11-07
[ [ "Alan", "A. T.", "" ], [ "Sultansoy", "S.", "" ] ]
We investigate the potentials of future high energy lepton-proton colliders to detect supersymmetric particles in the charged current type $lp\to\tilde\nu_l\tilde qX$, $l=e,\mu$, reactions. We also study their decays by using the mass spectrum given in the Technical Design Report of ATLAS Collaboration (SUGRA Point 6 corresponding to large $tan\beta$).
1310.4675
Christophe Royon
C. Royon
Forward physics with tagged protons at the LHC: QCD and anomalous couplings
Proceedings of the Low x 2013 workshop, May 30 - June 4 2013, Rehovot and Eilat, Israel
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present some physics topics that can be studied at the LHC using proton tagging. We distinguish the QCD (Pomeron structure, BFKL analysis...) from the exploratory physics topics (HIggs boson, anomalous couplings between photons and $W/Z$ bosons
[ { "created": "Thu, 17 Oct 2013 12:40:02 GMT", "version": "v1" } ]
2013-10-18
[ [ "Royon", "C.", "" ] ]
We present some physics topics that can be studied at the LHC using proton tagging. We distinguish the QCD (Pomeron structure, BFKL analysis...) from the exploratory physics topics (HIggs boson, anomalous couplings between photons and $W/Z$ bosons
hep-ph/0306201
Krzysztof Urbanowski
K. Urbanowski
CPT symmetry and properties of the exact and approximate effective Hamiltonians for the neutral kaon complex
LaTex2e, 18 pages, Talk given at the conference on "Symmetry in Nonlinear Mathematical Physics", June 23 -- 29, 2003, Institute of Mathematics, National Academy of Sciences of Ukraine, Kiev, Ukraine; typos corrected
EconfC0306234:973-980,2003
null
null
hep-ph
null
We start from a discussion of the general form and general CP-- and CPT-- transformation properties of the Lee--Oehme--Yang (LOY) effective Hamiltonian for the neutral kaon complex. Next we show that there exists an approximation which is more accurate than the LOY, and which leads to an effective Hamiltonian whose diagonal matrix elements posses CPT transformation properties, which differ from those of the LOY effective Hamiltonian. These properties of the mentioned effective Hamiltonians are compared with the properties of the exact effective Hamiltonian for the neutral kaon complex. We show that the diagonal matrix elements of the exact effective Hamiltonian governing the time evolution in the subspace of states of an unstable particle and its antiparticle need not be equal at for $t > t_{0}$ ($t_{0}$ is the instant of creation of the pair) when the total system under consideration is CPT invariant but CP noninvariant. The unusual consequence of this result is that, contrary to the properties of stable particles, the masses of the unstable particle "1" and its antiparticle "2" need not be equal for $t \gg t_{0}$ in the case of preserved CPT and violated CP symmetries.
[ { "created": "Sun, 22 Jun 2003 08:08:19 GMT", "version": "v1" }, { "created": "Sun, 6 Jul 2003 15:29:06 GMT", "version": "v2" }, { "created": "Mon, 14 Jul 2003 13:46:47 GMT", "version": "v3" } ]
2008-11-26
[ [ "Urbanowski", "K.", "" ] ]
We start from a discussion of the general form and general CP-- and CPT-- transformation properties of the Lee--Oehme--Yang (LOY) effective Hamiltonian for the neutral kaon complex. Next we show that there exists an approximation which is more accurate than the LOY, and which leads to an effective Hamiltonian whose diagonal matrix elements posses CPT transformation properties, which differ from those of the LOY effective Hamiltonian. These properties of the mentioned effective Hamiltonians are compared with the properties of the exact effective Hamiltonian for the neutral kaon complex. We show that the diagonal matrix elements of the exact effective Hamiltonian governing the time evolution in the subspace of states of an unstable particle and its antiparticle need not be equal at for $t > t_{0}$ ($t_{0}$ is the instant of creation of the pair) when the total system under consideration is CPT invariant but CP noninvariant. The unusual consequence of this result is that, contrary to the properties of stable particles, the masses of the unstable particle "1" and its antiparticle "2" need not be equal for $t \gg t_{0}$ in the case of preserved CPT and violated CP symmetries.
0803.3811
Andrew Blechman
Andrew E. Blechman, Siew-Phang Ng
QCD Corrections to K-Kbar Mixing in R-symmetric Supersymmetric Models
11 pages, 11 pdf-figures; updated acknowledgments and references, clarified relationship to Ref[17], clarified CP-violation section
JHEP 0806:043,2008
10.1088/1126-6708/2008/06/043
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The leading-log QCD corrections to K-Kbar mixing in R-symmetric supersymmetric models are computed using effective field theory techniques. The spectrum topology where the gluino is significantly heavier than the squarks is motivated and focused on. It is found that, like in the MSSM, QCD corrections can tighten the kaon mass difference bound by roughly a factor of three. CP violation is also briefly considered, where QCD corrections can constrain phases to be as much as a factor of ten smaller than the uncorrected value.
[ { "created": "Thu, 27 Mar 2008 19:28:35 GMT", "version": "v1" }, { "created": "Wed, 9 Apr 2008 17:59:17 GMT", "version": "v2" } ]
2009-11-13
[ [ "Blechman", "Andrew E.", "" ], [ "Ng", "Siew-Phang", "" ] ]
The leading-log QCD corrections to K-Kbar mixing in R-symmetric supersymmetric models are computed using effective field theory techniques. The spectrum topology where the gluino is significantly heavier than the squarks is motivated and focused on. It is found that, like in the MSSM, QCD corrections can tighten the kaon mass difference bound by roughly a factor of three. CP violation is also briefly considered, where QCD corrections can constrain phases to be as much as a factor of ten smaller than the uncorrected value.
1403.6535
Dario Buttazzo
Dario Buttazzo
Implications of the discovery of a Higgs boson with a mass of 125 GeV
PhD thesis. 223 pages, 46 figures, 24 tables
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The rather precise knowledge of the mass of the Higgs boson and of its couplings has important consequences for the physical phenomena taking place at the Fermi scale. We analyze some of these implications in the most motivated frameworks for physics at that energies - supersymmetry, models of a composite Higgs boson, and the Standard Model itself. At the same time, precision experiments in flavour physics require a highly non-generic structure of flavour and CP transitions. In any model of electroweak symmetry breaking with a relatively low scale of new phenomena, as motivated by naturalness, some mechanism has to be found in order to keep unwanted flavour effects under control. We devote particular attention to the consequences of the approximate U(2)^3 symmetry exhibited by the quarks of the Standard Model. The combined analysis of the indirect constraints from flavour, Higgs and electroweak physics will allow us to outline a picture of some most natural models of physics near the Fermi scale. Although non trivially, a few models emerge that look capable of accommodating a 125 GeV Higgs boson, consistently with all the other constraints, with new particles in an interesting range for discovery at the LHC, as well as associated flavour signals. This is particularly interesting in view of the forthcoming improvements in the direct experimental investigation of that energies. Finally, the measurement of the last parameter of the Standard Model - the Higgs quartic coupling - has important consequences even if no new physics is present close to the Fermi scale: its near-critical value, which puts the electroweak vacuum in a metastable state close to a phase transition, may have an interesting connection with Planck-scale physics. We derive the bound for electroweak vacuum stability with full two-loop precision, and explore some possible implication of near-criticality.
[ { "created": "Wed, 26 Mar 2014 00:11:59 GMT", "version": "v1" } ]
2014-03-27
[ [ "Buttazzo", "Dario", "" ] ]
The rather precise knowledge of the mass of the Higgs boson and of its couplings has important consequences for the physical phenomena taking place at the Fermi scale. We analyze some of these implications in the most motivated frameworks for physics at that energies - supersymmetry, models of a composite Higgs boson, and the Standard Model itself. At the same time, precision experiments in flavour physics require a highly non-generic structure of flavour and CP transitions. In any model of electroweak symmetry breaking with a relatively low scale of new phenomena, as motivated by naturalness, some mechanism has to be found in order to keep unwanted flavour effects under control. We devote particular attention to the consequences of the approximate U(2)^3 symmetry exhibited by the quarks of the Standard Model. The combined analysis of the indirect constraints from flavour, Higgs and electroweak physics will allow us to outline a picture of some most natural models of physics near the Fermi scale. Although non trivially, a few models emerge that look capable of accommodating a 125 GeV Higgs boson, consistently with all the other constraints, with new particles in an interesting range for discovery at the LHC, as well as associated flavour signals. This is particularly interesting in view of the forthcoming improvements in the direct experimental investigation of that energies. Finally, the measurement of the last parameter of the Standard Model - the Higgs quartic coupling - has important consequences even if no new physics is present close to the Fermi scale: its near-critical value, which puts the electroweak vacuum in a metastable state close to a phase transition, may have an interesting connection with Planck-scale physics. We derive the bound for electroweak vacuum stability with full two-loop precision, and explore some possible implication of near-criticality.
1311.2380
Seungwon Baek
Seungwon Baek, Hiroshi Okada
Hidden Sector Dark Matter with Global $U(1)_X$-symmetry and Fermi-LAT 130 GeV $\gamma$-ray Excess
5 pages, 2 figures; minor changes
null
10.1016/j.physletb.2013.12.033
KIAS-P13062
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We suggest a dark matter scenario which could contribute the possible anomaly observed by Fermi-LAT $\gamma$-ray space telescope. It is based on the model recently proposed by Weinberg. In our scenario the gamma-ray line signal comes from the fermionic dark matter ($M_{\rm DM}=214 $ GeV) annihilating into two light scalars with mass around 500 MeV which in turn decay into two neutral pions. Finally the pions can decay into two 130 GeV photons. The strong constraint from the direct detection leaves only the channel of the dark matter annihilation into two light scalars for both the relic density and the Fermi-LAT gamma-ray line signal. The resulting gamma-ray spectrum is rather broad and does not fit to the data perfectly, but the data also show there may be fluctuation in the spectrum. There is no associated $Z$-boson or Higgs boson production contrary to most other works where the signal comes from the loops of charged particles. The annihilation into the other SM particles are highly suppressed due to the small mixing from the direct detection. Future experiments with more data will give more clues on the possible scenarios.
[ { "created": "Mon, 11 Nov 2013 08:36:35 GMT", "version": "v1" }, { "created": "Mon, 18 Nov 2013 07:02:13 GMT", "version": "v2" }, { "created": "Mon, 9 Dec 2013 01:17:54 GMT", "version": "v3" } ]
2015-06-17
[ [ "Baek", "Seungwon", "" ], [ "Okada", "Hiroshi", "" ] ]
We suggest a dark matter scenario which could contribute the possible anomaly observed by Fermi-LAT $\gamma$-ray space telescope. It is based on the model recently proposed by Weinberg. In our scenario the gamma-ray line signal comes from the fermionic dark matter ($M_{\rm DM}=214 $ GeV) annihilating into two light scalars with mass around 500 MeV which in turn decay into two neutral pions. Finally the pions can decay into two 130 GeV photons. The strong constraint from the direct detection leaves only the channel of the dark matter annihilation into two light scalars for both the relic density and the Fermi-LAT gamma-ray line signal. The resulting gamma-ray spectrum is rather broad and does not fit to the data perfectly, but the data also show there may be fluctuation in the spectrum. There is no associated $Z$-boson or Higgs boson production contrary to most other works where the signal comes from the loops of charged particles. The annihilation into the other SM particles are highly suppressed due to the small mixing from the direct detection. Future experiments with more data will give more clues on the possible scenarios.
1502.07968
Luca Di Luzio
Borut Bajc, Luca Di Luzio
R-parity violation in SU(5)
30 pages, 1 figure. Revised version. To appear in JHEP
null
null
CETUP2013-033, NORDITA-2015-23
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We show that judiciously chosen R-parity violating terms in the minimal renormalizable supersymmetric SU(5) are able to correct all the phenomenologically wrong mass relations between down quarks and charged leptons. The model can accommodate neutrino masses as well. One of the most striking consequences is a large mixing between the electron and the Higgsino. We show that this can still be in accord with data in some regions of the parameter space and possibly falsified in future experiments.
[ { "created": "Fri, 27 Feb 2015 16:55:45 GMT", "version": "v1" }, { "created": "Tue, 21 Jul 2015 07:22:10 GMT", "version": "v2" } ]
2015-07-22
[ [ "Bajc", "Borut", "" ], [ "Di Luzio", "Luca", "" ] ]
We show that judiciously chosen R-parity violating terms in the minimal renormalizable supersymmetric SU(5) are able to correct all the phenomenologically wrong mass relations between down quarks and charged leptons. The model can accommodate neutrino masses as well. One of the most striking consequences is a large mixing between the electron and the Higgsino. We show that this can still be in accord with data in some regions of the parameter space and possibly falsified in future experiments.
2303.16586
Rui Vilela-Mendes
R. Vilela Mendes
T violation and the dark sector
6 pages Latex
null
null
null
hep-ph astro-ph.HE
http://creativecommons.org/licenses/by/4.0/
It is argued, as a working hypothesis, that "normal" and dark matter interactions can only be T and CP violating. One way to implement this idea is to consider that time reversal in dark matter is implemented, not by an antiunitary operator, but by a unitary operator. It is shown how this occurs naturally in the context of complex spacetime with an extended symmetry group.
[ { "created": "Wed, 29 Mar 2023 10:43:32 GMT", "version": "v1" } ]
2023-03-30
[ [ "Mendes", "R. Vilela", "" ] ]
It is argued, as a working hypothesis, that "normal" and dark matter interactions can only be T and CP violating. One way to implement this idea is to consider that time reversal in dark matter is implemented, not by an antiunitary operator, but by a unitary operator. It is shown how this occurs naturally in the context of complex spacetime with an extended symmetry group.
1608.03111
Ping Wang
Hongna Li and Ping Wang
Chiral extrapolation of nucleon axial charge $g_A$ in effective field theory
5 pages, 5 figures
null
10.1088/1674-1137/40/12/123106
null
hep-ph hep-lat
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The extrapolation of nucleon axial charge $g_A$ is investigated within the framework of heavy baryon chiral effective field theory. The intermediate octet and decuplet baryons are included in the one loop calculation. Finite range regularization is applied to improve the convergence in the quark-mass expansion. The lattice data from three different groups are used for the extrapolation. At physical pion mass, the extrapolated $g_A$ are all smaller than the experimental value.
[ { "created": "Wed, 10 Aug 2016 10:06:13 GMT", "version": "v1" } ]
2017-01-04
[ [ "Li", "Hongna", "" ], [ "Wang", "Ping", "" ] ]
The extrapolation of nucleon axial charge $g_A$ is investigated within the framework of heavy baryon chiral effective field theory. The intermediate octet and decuplet baryons are included in the one loop calculation. Finite range regularization is applied to improve the convergence in the quark-mass expansion. The lattice data from three different groups are used for the extrapolation. At physical pion mass, the extrapolated $g_A$ are all smaller than the experimental value.
2012.04323
Oliver Witzel
Jonathan M. Flynn, Ryan C. Hill, Andreas J\"uttner, Amarjit Soni, J. Tobias Tsang, Oliver Witzel
Nonperturbative calculations of form factors for exclusive semileptonic $B_{(s)}$ decays
6 pages, 3 figures, Proceedings of The 40th International Conference on High Energy Physics, ICHEP-2020; Jul 28-Aug 6, 2020, Prague, Czech Republic
null
null
SI-HEP-2020-33
hep-ph hep-lat
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Precise theoretical predictions derived from the Standard Model are a key ingredient in searches for new physics in the flavor sector. The large mass and long lifetime of the $b$ quark make processes involving $b$ quarks of particular interest. We use lattice simulations to perform nonperturbative QCD calculations for semileptonic $B_{(s)}$ decays. We present results from our determinations of $B_s\to D_s \ell \nu$ and $B_s\to K \ell \nu$ semileptonic form factors and provide an outlook for our $B\to \pi\ell\nu$ calculation. In addition we discuss the determination of $R$-ratios testing lepton-flavor universality and suggest use of an improved ratio. Our calculations are based on the set of 2+1 flavor domain wall Iwasaki gauge field configurations generated by the RBC-UKQCD collaboration featuring three lattice spacings of $1/a = 1.78$, $2.38$, and $2.79\,\text{GeV}$. Heavy $b$-quarks are simulated using the relativistic heavy quark action.
[ { "created": "Tue, 8 Dec 2020 09:54:42 GMT", "version": "v1" } ]
2020-12-09
[ [ "Flynn", "Jonathan M.", "" ], [ "Hill", "Ryan C.", "" ], [ "Jüttner", "Andreas", "" ], [ "Soni", "Amarjit", "" ], [ "Tsang", "J. Tobias", "" ], [ "Witzel", "Oliver", "" ] ]
Precise theoretical predictions derived from the Standard Model are a key ingredient in searches for new physics in the flavor sector. The large mass and long lifetime of the $b$ quark make processes involving $b$ quarks of particular interest. We use lattice simulations to perform nonperturbative QCD calculations for semileptonic $B_{(s)}$ decays. We present results from our determinations of $B_s\to D_s \ell \nu$ and $B_s\to K \ell \nu$ semileptonic form factors and provide an outlook for our $B\to \pi\ell\nu$ calculation. In addition we discuss the determination of $R$-ratios testing lepton-flavor universality and suggest use of an improved ratio. Our calculations are based on the set of 2+1 flavor domain wall Iwasaki gauge field configurations generated by the RBC-UKQCD collaboration featuring three lattice spacings of $1/a = 1.78$, $2.38$, and $2.79\,\text{GeV}$. Heavy $b$-quarks are simulated using the relativistic heavy quark action.
2210.08522
Ying Li
Zhi-Tian Zou, Wen-Sheng Fang, Xin Liu, Ying Li
Analysis of CKM-Favored Quasi-Two-Body $B \to D (R\to) K \pi$ Decays in PQCD Approach
18 pages, 1 figures
null
10.1140/epjc/s10052-022-11060-y
null
hep-ph hep-ex
http://creativecommons.org/licenses/by/4.0/
LHCb Collaboration studied the resonant structure of $B_s\to \overline{D}^0K^-\pi^+$ decays using the Dalitz plot analysis technique, based on a data sample corresponding to an integrated luminosity of $3.0{\rm fb}^{-1}$ of $pp$ collision. The $K^-\pi^+$ components have been analyzed in the amplitude model, where the decay amplitude is modeled to be the resonant contributions with respect to the intermediate resonances $K^*(892)$, $K_0^*(1430)$ and $K_2^*(1430)$. Motivated by the experimental results, we investigate the color-favored quasi-two-body $B \to \overline{D}^0K\pi$ decays in the framework of the perturbative QCD (PQCD) approach. We calculate the the branching fractions by introducing the appropriate wave functions of $K\pi$ pair. Our results are in agreement well the available data, and others can be tested in LHCb and Belle-II experiments. Using the narrow-width-approximation, we also extract the branching fractions of the corresponding two-body $B\to \overline D R$ decays, which agree to the previous theoretical calculations and the experimental data within the errors. There are no $CP$ asymmetries in these decays in the standard model, because these decays are all governed by only the tree operators.
[ { "created": "Sun, 16 Oct 2022 12:50:24 GMT", "version": "v1" } ]
2022-12-14
[ [ "Zou", "Zhi-Tian", "" ], [ "Fang", "Wen-Sheng", "" ], [ "Liu", "Xin", "" ], [ "Li", "Ying", "" ] ]
LHCb Collaboration studied the resonant structure of $B_s\to \overline{D}^0K^-\pi^+$ decays using the Dalitz plot analysis technique, based on a data sample corresponding to an integrated luminosity of $3.0{\rm fb}^{-1}$ of $pp$ collision. The $K^-\pi^+$ components have been analyzed in the amplitude model, where the decay amplitude is modeled to be the resonant contributions with respect to the intermediate resonances $K^*(892)$, $K_0^*(1430)$ and $K_2^*(1430)$. Motivated by the experimental results, we investigate the color-favored quasi-two-body $B \to \overline{D}^0K\pi$ decays in the framework of the perturbative QCD (PQCD) approach. We calculate the the branching fractions by introducing the appropriate wave functions of $K\pi$ pair. Our results are in agreement well the available data, and others can be tested in LHCb and Belle-II experiments. Using the narrow-width-approximation, we also extract the branching fractions of the corresponding two-body $B\to \overline D R$ decays, which agree to the previous theoretical calculations and the experimental data within the errors. There are no $CP$ asymmetries in these decays in the standard model, because these decays are all governed by only the tree operators.
2006.16027
Hua-Xing Chen
Hua-Xing Chen, Wei Chen, Xiang Liu and Shi-Lin Zhu
Strong decays of fully-charm tetraquarks into di-charmonia
8 pages, 1 figure, 3 tables, to be published in Science Bulletin
Sci. Bull. 65 (2020) 1994-2000
10.1016/j.scib.2020.08.038
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study strong decays of the possible fully-charm tetraquarks recently observed by LHCb, and calculate their relative branching ratios through the Fierz rearrangement. Together with our previous QCD sum rule study [Phys. Lett. B 773, 247 (2017)], our results suggest that the broad structure around $6.2$-$6.8$ GeV can be interpreted as an $S$-wave $cc\bar c \bar c$ tetraquark state with $J^{PC} = 0^{++}$ or $2^{++}$, and the narrow structure around 6.9 GeV can be interpreted as a $P$-wave one with $J^{PC} = 0^{-+}$ or $1^{-+}$. These structures were observed in the di-$J/\psi$ invariant mass spectrum, and we propose to confirm them in the di-$\eta_c$, $J/\psi h_c$, $\eta_c \chi_{c0}$, and $\eta_c \chi_{c1}$ channels. We also propose to search for their partner states having the negative charge-conjugation parity in the $J/\psi \eta_c$, $J/\psi \chi_{c0}$, $J/\psi \chi_{c1}$, and $\eta_c h_c$ channels.
[ { "created": "Mon, 29 Jun 2020 13:17:24 GMT", "version": "v1" }, { "created": "Sun, 30 Aug 2020 02:44:07 GMT", "version": "v2" } ]
2020-10-19
[ [ "Chen", "Hua-Xing", "" ], [ "Chen", "Wei", "" ], [ "Liu", "Xiang", "" ], [ "Zhu", "Shi-Lin", "" ] ]
We study strong decays of the possible fully-charm tetraquarks recently observed by LHCb, and calculate their relative branching ratios through the Fierz rearrangement. Together with our previous QCD sum rule study [Phys. Lett. B 773, 247 (2017)], our results suggest that the broad structure around $6.2$-$6.8$ GeV can be interpreted as an $S$-wave $cc\bar c \bar c$ tetraquark state with $J^{PC} = 0^{++}$ or $2^{++}$, and the narrow structure around 6.9 GeV can be interpreted as a $P$-wave one with $J^{PC} = 0^{-+}$ or $1^{-+}$. These structures were observed in the di-$J/\psi$ invariant mass spectrum, and we propose to confirm them in the di-$\eta_c$, $J/\psi h_c$, $\eta_c \chi_{c0}$, and $\eta_c \chi_{c1}$ channels. We also propose to search for their partner states having the negative charge-conjugation parity in the $J/\psi \eta_c$, $J/\psi \chi_{c0}$, $J/\psi \chi_{c1}$, and $\eta_c h_c$ channels.
2012.10144
Xuangong Wang
X. G. Wang, A. W. Thomas
Relativistic mean-field corrections for interactions of dark matter particles with nucleons
9 pages, 1 table
Phys. Rev. C 103, 034606 (2021)
10.1103/PhysRevC.103.034606
ADP-20-36/T1146
hep-ph hep-ex nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate the interactions of weakly interacting massive particles (WIMPS) with nucleons in nuclear medium by taking into account the effect of nuclear dynamics. We derive the nonrelativistic effective operators starting from the relativistic mean-field approximation. Certain interactions receive non-negligible corrections, which may significantly change the sensitivities of WIMP-nucleus scattering cross section to these effective operators.
[ { "created": "Fri, 18 Dec 2020 10:12:36 GMT", "version": "v1" }, { "created": "Sat, 6 Mar 2021 02:19:15 GMT", "version": "v2" } ]
2021-03-09
[ [ "Wang", "X. G.", "" ], [ "Thomas", "A. W.", "" ] ]
We investigate the interactions of weakly interacting massive particles (WIMPS) with nucleons in nuclear medium by taking into account the effect of nuclear dynamics. We derive the nonrelativistic effective operators starting from the relativistic mean-field approximation. Certain interactions receive non-negligible corrections, which may significantly change the sensitivities of WIMP-nucleus scattering cross section to these effective operators.
2305.05155
Katharena Christy
Katharena Christy, Jason Kumar, Pearl Sandick
Constraining $p$-wave Dark Matter Annihilation with Gamma-ray Observations of M87
10 pages, 4 figures; updated to match version accepted by PRD
null
10.1103/PhysRevD.108.103042
null
hep-ph astro-ph.CO astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider constraints on $p$-wave dark matter in a dark matter spike surrounding the supermassive black hole at the center of M87. Owing to the large mass of the black hole, and resulting large velocity dispersion for the dark matter particles in the spike, it is possible for Fermi-LAT and MAGIC data to place tight constraints on $p$-wave annihilation, which would be far more stringent than those placed by observations of dwarf spheroidal galaxies. Indeed, for optimistic choices of the spike parameters, gamma-ray data would exclude thermal $p$-wave dark matter models with a particle mass $\lesssim {10}~\rm TeV$. But there is significant uncertainty in the properties and parameters of the spike, and for less optimistic scenarios, thermal dark matter candidates would be completely unconstrained. In addition to better understanding the spike parameters, a second key to improving constraints on dark matter annihilation is an accurate astrophysical background model.
[ { "created": "Tue, 9 May 2023 03:36:30 GMT", "version": "v1" }, { "created": "Tue, 28 Nov 2023 01:36:47 GMT", "version": "v2" } ]
2023-11-29
[ [ "Christy", "Katharena", "" ], [ "Kumar", "Jason", "" ], [ "Sandick", "Pearl", "" ] ]
We consider constraints on $p$-wave dark matter in a dark matter spike surrounding the supermassive black hole at the center of M87. Owing to the large mass of the black hole, and resulting large velocity dispersion for the dark matter particles in the spike, it is possible for Fermi-LAT and MAGIC data to place tight constraints on $p$-wave annihilation, which would be far more stringent than those placed by observations of dwarf spheroidal galaxies. Indeed, for optimistic choices of the spike parameters, gamma-ray data would exclude thermal $p$-wave dark matter models with a particle mass $\lesssim {10}~\rm TeV$. But there is significant uncertainty in the properties and parameters of the spike, and for less optimistic scenarios, thermal dark matter candidates would be completely unconstrained. In addition to better understanding the spike parameters, a second key to improving constraints on dark matter annihilation is an accurate astrophysical background model.
1111.6402
Christopher Smith
Jernej F. Kamenik, Christopher Smith
FCNC portals to the dark sector
55 pages. Minor corrections & references added. To appear in JHEP
null
10.1007/JHEP03(2012)090
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The most general basis of operators parametrizing a low-scale departure from the SM particle content is constructed. The SM gauge invariance is enforced, and operators of lowest dimensions are retained separately for a new light neutral particle of spin 0, 1/2, 1, and 3/2. The basis is further decomposed into couplings to the SM Higgs/gauge fields, to pairs of quark/lepton fields, and to baryon/lepton number violating combinations of fermion fields. This basis is then used to systematically investigate the discovery potential of the rare FCNC decays of the K and B mesons with missing energy in the final state. The most sensitive decay modes in the s to d, b to d, and b to s sectors are identified and compared for each type of couplings to the new invisible state.
[ { "created": "Mon, 28 Nov 2011 10:55:50 GMT", "version": "v1" }, { "created": "Tue, 27 Mar 2012 08:14:40 GMT", "version": "v2" } ]
2015-06-03
[ [ "Kamenik", "Jernej F.", "" ], [ "Smith", "Christopher", "" ] ]
The most general basis of operators parametrizing a low-scale departure from the SM particle content is constructed. The SM gauge invariance is enforced, and operators of lowest dimensions are retained separately for a new light neutral particle of spin 0, 1/2, 1, and 3/2. The basis is further decomposed into couplings to the SM Higgs/gauge fields, to pairs of quark/lepton fields, and to baryon/lepton number violating combinations of fermion fields. This basis is then used to systematically investigate the discovery potential of the rare FCNC decays of the K and B mesons with missing energy in the final state. The most sensitive decay modes in the s to d, b to d, and b to s sectors are identified and compared for each type of couplings to the new invisible state.
hep-ph/0411403
Stefano Rigolin
S. Rigolin
Degeneracies at a beta-Beam and a Super-Beam Facility
5 pages, 7 eps figures
Nucl.Phys.Proc.Suppl.145:203-207,2005
10.1016/j.nuclphysbps.2005.04.007
null
hep-ph
null
The presence of degeneracies can considerably worsen the measure of the neutrino oscillation parameters $\theta_{13}$ and $\delta$. We study the physics reach of a specific ``CERN'' setup, using a standard $\beta$-Beam and Super-Beam facility. These facilities have a similar sensitivity in both parameters. Their combination does not provide any dramatic improvement as expected due to their almost identical L/E ratio. We analyse if adding the correspondent disappearance channels can help in reducing the effect of degeneracies in the $(\theta_{13},\delta)$ measure.
[ { "created": "Tue, 30 Nov 2004 17:38:02 GMT", "version": "v1" } ]
2014-11-18
[ [ "Rigolin", "S.", "" ] ]
The presence of degeneracies can considerably worsen the measure of the neutrino oscillation parameters $\theta_{13}$ and $\delta$. We study the physics reach of a specific ``CERN'' setup, using a standard $\beta$-Beam and Super-Beam facility. These facilities have a similar sensitivity in both parameters. Their combination does not provide any dramatic improvement as expected due to their almost identical L/E ratio. We analyse if adding the correspondent disappearance channels can help in reducing the effect of degeneracies in the $(\theta_{13},\delta)$ measure.
1207.6900
Carlos Merino
C. Merino, C. Pajares, and Yu. M. Shabelski
Production of secondaries in soft p+pb collisions at LHC
18 pages and 10 figures. arXiv admin note: text overlap with arXiv:0802.2195
null
10.1140/epjc/s10052-012-2266-9
null
hep-ph hep-ex nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We calculate the inclusive spectra of secondaries produced in soft (minimum bias) p+Pb collisions in the framework of Quark-Gluon String Model at LHC energy, and by taking into account the inelastic screening corrections (percolation effects). The role of these effects is expected to be very large at very high energies, and they should decrease the spectra about 3 times in the midrapidity region and increase them about 2 times in the fragmentation region at the energy of LHC.
[ { "created": "Mon, 30 Jul 2012 11:37:45 GMT", "version": "v1" }, { "created": "Tue, 20 Nov 2012 12:47:37 GMT", "version": "v2" } ]
2015-06-05
[ [ "Merino", "C.", "" ], [ "Pajares", "C.", "" ], [ "Shabelski", "Yu. M.", "" ] ]
We calculate the inclusive spectra of secondaries produced in soft (minimum bias) p+Pb collisions in the framework of Quark-Gluon String Model at LHC energy, and by taking into account the inelastic screening corrections (percolation effects). The role of these effects is expected to be very large at very high energies, and they should decrease the spectra about 3 times in the midrapidity region and increase them about 2 times in the fragmentation region at the energy of LHC.
1305.3907
David Blaschke
D. Blaschke, M. Buballa, A. Dubinin, G. Roepke, D. Zablocki
Generalized Beth--Uhlenbeck approach to mesons and diquarks in hot, dense quark matter
29 pages, 5 figures, revised version accepted for Annals of Physics
Annals Phys. 348 (2014) 228 - 255
10.1016/j.aop.2014.06.002
null
hep-ph nucl-th physics.plasm-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
An important first step in the program of hadronization of chiral quark models is the bosonization in meson and diquark channels. This procedure is presented at finite temperatures and chemical potentials for the SU(2) flavor case of the NJL model with special emphasis on the mixing between scalar meson and scalar diquark modes which occurs in the 2SC color superconducting phase. The thermodynamic potential is obtained in the gaussian approximation for the meson and diquark fields and it is given the Beth-Uhlenbeck form. This allows a detailed discussion of bound state dissociation in hot, dense matter (Mott effect) in terms of the in-medium scattering phase shift of two-particle correlations. It is shown for the case without meson-diquark mixing that the phase shift can be separated into a continuum and a resonance part. In the latter, the Mott transition manifests itself by a change of the phase shift at threshold by \pi\ in accordance with Levinson's theorem, when a bound state transforms to a resonance in the scattering continuum. The consequences for the contribution of pionic correlations to the pressure are discussed by evaluating the Beth-Uhlenbeck equation of state in different approximations. A similar discussion is performed for the scalar diquark channel in the normal phase. Further developments and applications of the developed approach are outlined.
[ { "created": "Thu, 16 May 2013 19:58:58 GMT", "version": "v1" }, { "created": "Mon, 6 Jan 2014 15:34:35 GMT", "version": "v2" }, { "created": "Wed, 28 May 2014 02:20:29 GMT", "version": "v3" } ]
2014-06-30
[ [ "Blaschke", "D.", "" ], [ "Buballa", "M.", "" ], [ "Dubinin", "A.", "" ], [ "Roepke", "G.", "" ], [ "Zablocki", "D.", "" ] ]
An important first step in the program of hadronization of chiral quark models is the bosonization in meson and diquark channels. This procedure is presented at finite temperatures and chemical potentials for the SU(2) flavor case of the NJL model with special emphasis on the mixing between scalar meson and scalar diquark modes which occurs in the 2SC color superconducting phase. The thermodynamic potential is obtained in the gaussian approximation for the meson and diquark fields and it is given the Beth-Uhlenbeck form. This allows a detailed discussion of bound state dissociation in hot, dense matter (Mott effect) in terms of the in-medium scattering phase shift of two-particle correlations. It is shown for the case without meson-diquark mixing that the phase shift can be separated into a continuum and a resonance part. In the latter, the Mott transition manifests itself by a change of the phase shift at threshold by \pi\ in accordance with Levinson's theorem, when a bound state transforms to a resonance in the scattering continuum. The consequences for the contribution of pionic correlations to the pressure are discussed by evaluating the Beth-Uhlenbeck equation of state in different approximations. A similar discussion is performed for the scalar diquark channel in the normal phase. Further developments and applications of the developed approach are outlined.
1907.13624
Federico Buccioni
Federico Buccioni, Stefan Kallweit, Stefano Pozzorini, Max Zoller
NLO QCD predictions for $t\bar{t}b\bar{b}$ production in association with a light jet at the LHC
37 pages, 18 figures, 6 tables
null
10.1007/JHEP12(2019)015
PSI-PR-19-16, ZU-TH 38/19
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Theoretical predictions for ttbb production are of crucial importance for ttH measurements in the H->bb channel at the LHC. To address the large uncertainties associated with the modelling of extra QCD radiation in ttbb events, in this paper we present a calculation of pp->ttbbj at NLO QCD. The behaviour of NLO corrections is analysed in a variety of observables, and to assess theoretical uncertainties we use factor-two rescalings as well as different dynamic scales. In this context, we propose a systematic alignment of dynamic scales that makes it possible to disentangle normalisation and shape uncertainties in a transparent way. Scale uncertainties at NLO are typically at the level of 20-30% in fiducial cross sections, and below 10% for the shapes of distributions. The kinematics of QCD radiation is investigated in detail, including the effects of its recoil on the objects of the ttbb system. In particular, we discuss various azimuthal correlations that allow one to charaterise the QCD recoil pattern in a precise and transparent way. In general, the calculation at hand provides a variety of precise benchmarks that can be used to validate the modelling of QCD radiation in ttbb generators. Moreover, as we will argue, pp->ttbbj at NLO entails information that can be used to gain insights into the perturbative convergence of the inclusive ttbb cross section beyond NLO. Based on this idea, we address the issue of the large NLO K-factor observed in the ttbb cross section, and we provide evidence that supports the reduction of this K-factor through a mild adjustment of the QCD scales that are conventionally used for this process. The presented 2->5 NLO calculations have been carried out using OpenLoops 2 in combination with Sherpa and Munich.
[ { "created": "Wed, 31 Jul 2019 17:50:36 GMT", "version": "v1" }, { "created": "Tue, 10 Dec 2019 12:18:00 GMT", "version": "v2" } ]
2019-12-11
[ [ "Buccioni", "Federico", "" ], [ "Kallweit", "Stefan", "" ], [ "Pozzorini", "Stefano", "" ], [ "Zoller", "Max", "" ] ]
Theoretical predictions for ttbb production are of crucial importance for ttH measurements in the H->bb channel at the LHC. To address the large uncertainties associated with the modelling of extra QCD radiation in ttbb events, in this paper we present a calculation of pp->ttbbj at NLO QCD. The behaviour of NLO corrections is analysed in a variety of observables, and to assess theoretical uncertainties we use factor-two rescalings as well as different dynamic scales. In this context, we propose a systematic alignment of dynamic scales that makes it possible to disentangle normalisation and shape uncertainties in a transparent way. Scale uncertainties at NLO are typically at the level of 20-30% in fiducial cross sections, and below 10% for the shapes of distributions. The kinematics of QCD radiation is investigated in detail, including the effects of its recoil on the objects of the ttbb system. In particular, we discuss various azimuthal correlations that allow one to charaterise the QCD recoil pattern in a precise and transparent way. In general, the calculation at hand provides a variety of precise benchmarks that can be used to validate the modelling of QCD radiation in ttbb generators. Moreover, as we will argue, pp->ttbbj at NLO entails information that can be used to gain insights into the perturbative convergence of the inclusive ttbb cross section beyond NLO. Based on this idea, we address the issue of the large NLO K-factor observed in the ttbb cross section, and we provide evidence that supports the reduction of this K-factor through a mild adjustment of the QCD scales that are conventionally used for this process. The presented 2->5 NLO calculations have been carried out using OpenLoops 2 in combination with Sherpa and Munich.
hep-ph/9705228
Kazuhiro Tobe
K.-I. Izawa, Y. Nomura, K. Tobe, and T. Yanagida
Direct-Transmission Models of Dynamical Supersymmetry Breaking
18 pages, Latex, 5 Postscript figures
Phys.Rev.D56:2886-2892,1997
10.1103/PhysRevD.56.2886
UT-774
hep-ph
null
We systematically construct gauge-mediated supersymmetry(SUSY)-breaking models with direct transmission of SUSY-breaking effects to the standard-model sector. We obtain a natural model with the gravitino mass $m_{3/2}$ smaller than 1 keV as required from the standard cosmology. If all Yukawa coupling constants are of order one,the SUSY-breaking scale $m_{SUSY}$ transmitted into the standard-model sector is given by $m_{SUSY} \simeq 0.1 \alpha_i/(4\pi) \Lambda$ where $\Lambda$ is the original dynamical SUSY-breaking scale. Imposing $m_{SUSY} \simeq (10^2-10^3)$ GeV, we get $\Lambda \simeq (10^5-10^6)$ GeV, which yields the gravitino mass $m_{3/2}\simeq (10^{-2}-1)$ keV.
[ { "created": "Mon, 5 May 1997 08:22:38 GMT", "version": "v1" } ]
2010-04-06
[ [ "Izawa", "K. -I.", "" ], [ "Nomura", "Y.", "" ], [ "Tobe", "K.", "" ], [ "Yanagida", "T.", "" ] ]
We systematically construct gauge-mediated supersymmetry(SUSY)-breaking models with direct transmission of SUSY-breaking effects to the standard-model sector. We obtain a natural model with the gravitino mass $m_{3/2}$ smaller than 1 keV as required from the standard cosmology. If all Yukawa coupling constants are of order one,the SUSY-breaking scale $m_{SUSY}$ transmitted into the standard-model sector is given by $m_{SUSY} \simeq 0.1 \alpha_i/(4\pi) \Lambda$ where $\Lambda$ is the original dynamical SUSY-breaking scale. Imposing $m_{SUSY} \simeq (10^2-10^3)$ GeV, we get $\Lambda \simeq (10^5-10^6)$ GeV, which yields the gravitino mass $m_{3/2}\simeq (10^{-2}-1)$ keV.
1810.12874
Elena G. Ferreiro
Elena G. Ferreiro
Global description of bottomonium suppression in proton-nucleus and nucleus-nucleus collisions at LHC energies
6 pages, 7 figures. Contribution to the Proceedings of the XXVI International Workshop on Deep-Inelastic Scattering and Related Subjects (DIS2018), 16-20 April 2018 Kobe, Japan. Based on arXiv:1804.04474
null
null
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We show that we can reach a global and coherent description of bottomonium suppression in both proton-nucleus and nucleus-nucleus collisions at the LHC energies. The measured relative suppression of the excited bottomonium states as compared to their ground state allows us to constrain the scattering cross sections between the bottomonia and the comovers created during the collisions. Our result hints at a similar energy distribution of these comovers in the environment created by proton-nucleus and nucleus-nucleus collisions. Along the way of our study, we also update our knowledge for the bottomonium feed-down pattern and our comprehension on the modification of the nuclear parton distribution functions in proton-nucleus collisions. We present our results for $p$Pb collisions at 5.02 and 8.16 TeV and for PbPb collisions at 2.76 and 5.02 TeV.
[ { "created": "Tue, 30 Oct 2018 17:19:32 GMT", "version": "v1" } ]
2018-10-31
[ [ "Ferreiro", "Elena G.", "" ] ]
We show that we can reach a global and coherent description of bottomonium suppression in both proton-nucleus and nucleus-nucleus collisions at the LHC energies. The measured relative suppression of the excited bottomonium states as compared to their ground state allows us to constrain the scattering cross sections between the bottomonia and the comovers created during the collisions. Our result hints at a similar energy distribution of these comovers in the environment created by proton-nucleus and nucleus-nucleus collisions. Along the way of our study, we also update our knowledge for the bottomonium feed-down pattern and our comprehension on the modification of the nuclear parton distribution functions in proton-nucleus collisions. We present our results for $p$Pb collisions at 5.02 and 8.16 TeV and for PbPb collisions at 2.76 and 5.02 TeV.
hep-ph/9404291
null
M. Doser and A. Palano
Exotic Searches
25 pages, LaTex, 22 Figures (available from the authors on request), BARI-TH/94-172
null
null
null
hep-ph
null
The experimental information on the search for non $q \bar q$ mesons as glueballs, hybrids and multiquark states is reviewed. Candidate states which are particularly amenable to detailed study by accumulating large samples of $J/\psi$, $\eta_c$, $\chi$ decays at a $\tau$-charm factory are discussed.
[ { "created": "Tue, 19 Apr 1994 13:11:00 GMT", "version": "v1" } ]
2007-05-23
[ [ "Doser", "M.", "" ], [ "Palano", "A.", "" ] ]
The experimental information on the search for non $q \bar q$ mesons as glueballs, hybrids and multiquark states is reviewed. Candidate states which are particularly amenable to detailed study by accumulating large samples of $J/\psi$, $\eta_c$, $\chi$ decays at a $\tau$-charm factory are discussed.
0710.5620
Federico Mescia DR
Federico Mescia (for the FlaviaNet Working Group on Kaon Decays)
Precision tests with Kl3 and Kl2 decays
Contributed to the International Europhysics Conference on High Energy Physics (EPS-HEP2007), Manchester, England, 19-25 Jul 2007
J.Phys.Conf.Ser.110:052036,2008
10.1088/1742-6596/110/5/052036
null
hep-ph
null
The analysis made in 2000 indicated that the unitarity relation Vud^2 + Vus^2 + Vub^2 = 1 might be broken at the 2.3 sigma level. At that time, however, Vus was inferred from old experimental data. Since then, a great experimental and theoretical effort has been invested to understand the source of that discrepancy. Thanks to the new and improved measurements by BNL-E865, KLOE, KTeV, ISTRA+ and NA48, the old Kl3 decay rate got shifted so that the new Vus is now consistent with unitarity. On the theory side, much progress in the lattice QCD has been made in order to tame the systematic uncertainties related to the computation of the Kl3 form factors. This joint progress allowed to assess the validity of the CKM unitarity relation at the level of less than 1%. The key challenge of the future lattice studies will be to simulate lighter pions in the region in which ChPT predictions apply. Also interesting is the recent progress in accurately computing the kaon and pion decay constants on the lattice, which then give us access to Vus and Vud from the corresponding leptonic decays. In addition, we discuss that the Kl3 and Kl2 decays offer the possibility to test various scenarios of physics beyond Standard Model.
[ { "created": "Tue, 30 Oct 2007 17:54:26 GMT", "version": "v1" } ]
2019-08-14
[ [ "Mescia", "Federico", "", "for the FlaviaNet Working Group on Kaon Decays" ] ]
The analysis made in 2000 indicated that the unitarity relation Vud^2 + Vus^2 + Vub^2 = 1 might be broken at the 2.3 sigma level. At that time, however, Vus was inferred from old experimental data. Since then, a great experimental and theoretical effort has been invested to understand the source of that discrepancy. Thanks to the new and improved measurements by BNL-E865, KLOE, KTeV, ISTRA+ and NA48, the old Kl3 decay rate got shifted so that the new Vus is now consistent with unitarity. On the theory side, much progress in the lattice QCD has been made in order to tame the systematic uncertainties related to the computation of the Kl3 form factors. This joint progress allowed to assess the validity of the CKM unitarity relation at the level of less than 1%. The key challenge of the future lattice studies will be to simulate lighter pions in the region in which ChPT predictions apply. Also interesting is the recent progress in accurately computing the kaon and pion decay constants on the lattice, which then give us access to Vus and Vud from the corresponding leptonic decays. In addition, we discuss that the Kl3 and Kl2 decays offer the possibility to test various scenarios of physics beyond Standard Model.
0804.0214
Zainul Abidin
Zainul Abidin and Carl E. Carlson (William and Mary)
Gravitational Form Factors in the Axial Sector from an AdS/QCD Model
6 pages, 1 figure
Phys.Rev.D77:115021,2008
10.1103/PhysRevD.77.115021
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We calculate the stress tensor, or energy-momentum tensor, form factors of the pion and of axial vector mesons in the chiral limit of a hard wall AdS/CFT model of QCD. One (of the two) pion gravitational form factors is directly related to the second moment of the pion generalized parton distribution, thus providing a sum rule for the latter. As was also the case for vector mesons, both the pion and the axial vector mesons appear strikingly more compact measured by the gravitational form factor than by the electromagnetic form factor.
[ { "created": "Tue, 1 Apr 2008 17:19:19 GMT", "version": "v1" } ]
2008-11-26
[ [ "Abidin", "Zainul", "", "William and Mary" ], [ "Carlson", "Carl E.", "", "William and Mary" ] ]
We calculate the stress tensor, or energy-momentum tensor, form factors of the pion and of axial vector mesons in the chiral limit of a hard wall AdS/CFT model of QCD. One (of the two) pion gravitational form factors is directly related to the second moment of the pion generalized parton distribution, thus providing a sum rule for the latter. As was also the case for vector mesons, both the pion and the axial vector mesons appear strikingly more compact measured by the gravitational form factor than by the electromagnetic form factor.
hep-ph/9602300
Robin Stuart
Robin G. Stuart (Randall Laboratory of Physics)
Model-independent Representation of Electroweak Data
14 pages LaTeX. Uses amssymb.sty. Minor changes to text
Phys. Rev. D 56, 1515 (1997)
10.1103/PhysRevD.56.1515
UM-TH-96-02
hep-ph
null
General model-independent expressions are developed for the polarized and unpolarized cross-sections for $e^+e^-\to f\bar f$ near the $Z^0$ resonance. The expressions assume only the analyticity of S-matrix elements. Angular dependence is included by means of a partial wave expansion. The resulting simple forms are suitable for use in fitting data or in Monte Carlo event generators. A distinction is made between model-independent and model-dependent QED corrections and a simple closed expression is given for the effect of initial-final state bremsstrahlung and virtual QED corrections.
[ { "created": "Wed, 14 Feb 1996 01:33:58 GMT", "version": "v1" }, { "created": "Tue, 7 May 1996 16:51:40 GMT", "version": "v2" }, { "created": "Wed, 16 Jul 1997 20:32:14 GMT", "version": "v3" } ]
2016-08-24
[ [ "Stuart", "Robin G.", "", "Randall Laboratory of Physics" ] ]
General model-independent expressions are developed for the polarized and unpolarized cross-sections for $e^+e^-\to f\bar f$ near the $Z^0$ resonance. The expressions assume only the analyticity of S-matrix elements. Angular dependence is included by means of a partial wave expansion. The resulting simple forms are suitable for use in fitting data or in Monte Carlo event generators. A distinction is made between model-independent and model-dependent QED corrections and a simple closed expression is given for the effect of initial-final state bremsstrahlung and virtual QED corrections.
hep-ph/9510260
Paul Frampton
Paul H. Frampton
Flavors and Horizontal Symmetries
10 pages, latex
Prog.Theor.Phys.Suppl.123:327-336,1996
10.1143/PTPS.123.327
IFP-718-UNC
hep-ph
null
After a brief introduction to what are the basic flavor questions to be addressed, I introduce the underlying ideas of horizontal symmetries, with group $G_H$. For the purposes of specific model building, it is useful to classify models according to the scale at which $G_H$ is broken. I consider the three cases: below $m_t$; somewhat above $m_t$; and at $M_{GUT}$. After a discussion of the shadow sector in the $E_6 \times E_8'$ superstring, there is a summary.
[ { "created": "Tue, 10 Oct 1995 19:36:39 GMT", "version": "v1" } ]
2011-03-02
[ [ "Frampton", "Paul H.", "" ] ]
After a brief introduction to what are the basic flavor questions to be addressed, I introduce the underlying ideas of horizontal symmetries, with group $G_H$. For the purposes of specific model building, it is useful to classify models according to the scale at which $G_H$ is broken. I consider the three cases: below $m_t$; somewhat above $m_t$; and at $M_{GUT}$. After a discussion of the shadow sector in the $E_6 \times E_8'$ superstring, there is a summary.
1205.2688
James Cline
James M. Cline
130 GeV dark matter and the Fermi gamma-ray line
5 pages, 5 figures. v2: fixed error concerning EWPD; S becomes SU(2)_L singlet. Main results and predictions unchanged. v3: discussed need for S to decay. v4: elaborated S decay mechanism and collider signatures; v5: added WW and ZZ annihilation channels for relic density, and new XENON100 limit
null
10.1103/PhysRevD.86.015016
null
hep-ph astro-ph.CO astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Based on tentative evidence for a peak in the Fermi gamma-ray spectrum originating from near the center of the galaxy, it has been suggested that dark matter of mass ~130 GeV is annihilating directly into photons with a cross section ~24 times smaller than that needed for the thermal relic density. We propose a simple particle physics model in which the DM is a scalar X, with a coupling lambda_X X^2|S|^2 to a scalar multiplet S carrying electric charge, which allows for XX -> gamma gamma at one loop due to the virtual S. We predict a second monochromatic photon peak at 114 GeV due to XX-> gamma Z. The S is colored under a hidden sector SU(N) or QCD to help boost the XX -> gamma gamma cross section. The analogous coupling lambda_h h^2 |S|^2 to the Higgs boson can naturally increase the partial width for h -> gamma gamma by an amount comparable to its standard model value, as suggested by recent measurements from CMS. Due to the hidden sector SU(N) (or QCD), S binds to its antiparticle to form S-mesons, which will be pair-produced in colliders and then decay predominantly to XX, hh, or to glueballs of the SU(N) which subsequently decay to photons. The cross section for X on nucleons is close to the Xenon100 upper limit, suggesting that it should be discovered soon by direct detection.
[ { "created": "Fri, 11 May 2012 19:59:33 GMT", "version": "v1" }, { "created": "Tue, 15 May 2012 19:45:47 GMT", "version": "v2" }, { "created": "Wed, 30 May 2012 18:51:07 GMT", "version": "v3" }, { "created": "Mon, 11 Jun 2012 04:09:50 GMT", "version": "v4" }, { "created": "Wed, 25 Jul 2012 12:54:09 GMT", "version": "v5" } ]
2013-05-30
[ [ "Cline", "James M.", "" ] ]
Based on tentative evidence for a peak in the Fermi gamma-ray spectrum originating from near the center of the galaxy, it has been suggested that dark matter of mass ~130 GeV is annihilating directly into photons with a cross section ~24 times smaller than that needed for the thermal relic density. We propose a simple particle physics model in which the DM is a scalar X, with a coupling lambda_X X^2|S|^2 to a scalar multiplet S carrying electric charge, which allows for XX -> gamma gamma at one loop due to the virtual S. We predict a second monochromatic photon peak at 114 GeV due to XX-> gamma Z. The S is colored under a hidden sector SU(N) or QCD to help boost the XX -> gamma gamma cross section. The analogous coupling lambda_h h^2 |S|^2 to the Higgs boson can naturally increase the partial width for h -> gamma gamma by an amount comparable to its standard model value, as suggested by recent measurements from CMS. Due to the hidden sector SU(N) (or QCD), S binds to its antiparticle to form S-mesons, which will be pair-produced in colliders and then decay predominantly to XX, hh, or to glueballs of the SU(N) which subsequently decay to photons. The cross section for X on nucleons is close to the Xenon100 upper limit, suggesting that it should be discovered soon by direct detection.
0704.0293
Mikhail Voloshin
S. Dubynskiy, A. Le Yaouanc, L. Oliver, J.-C. Raynal and M.B. Voloshin
Isospin breaking in the yield of heavy meson pairs in e+e- annihilation near threshold
16 pages, 2 figures
Phys.Rev.D75:113001,2007
10.1103/PhysRevD.75.113001
FTPI-MINN-07/08, UMN-TH-2541/07, LPT-Orsay/07-19
hep-ph
null
We revisit the problem of interplay between the strong and the Coulomb interaction in the charged-to-neutral yield ratio for $B {\bar B}$ and $D {\bar D}$ pairs near their respective thresholds in $e^+e^-$ annihilation. We consider here a realistic situation with a resonant interaction in the isospin I=0 channel and a nonresonant strong scattering amplitude in the I=1 state. We find that the yield ratio has a smooth behavior depending on the scattering phase in the I=1 channel. The same approach is also applicable to the $K {\bar K}$ production at the $\phi(1020)$ resonance, where the Coulomb effect in the charged-to-neutral yield ratio is generally sensitive to the scattering phases in both the isoscalar and the isovector channels. Furthermore, we apply the same approach to the treatment of the effect of the isotopic mass difference between the charged and neutral mesons and argue that the strong-scattering effects generally result in a modification to the pure kinematical effect of this mass difference.
[ { "created": "Tue, 3 Apr 2007 18:57:46 GMT", "version": "v1" } ]
2008-11-26
[ [ "Dubynskiy", "S.", "" ], [ "Yaouanc", "A. Le", "" ], [ "Oliver", "L.", "" ], [ "Raynal", "J. -C.", "" ], [ "Voloshin", "M. B.", "" ] ]
We revisit the problem of interplay between the strong and the Coulomb interaction in the charged-to-neutral yield ratio for $B {\bar B}$ and $D {\bar D}$ pairs near their respective thresholds in $e^+e^-$ annihilation. We consider here a realistic situation with a resonant interaction in the isospin I=0 channel and a nonresonant strong scattering amplitude in the I=1 state. We find that the yield ratio has a smooth behavior depending on the scattering phase in the I=1 channel. The same approach is also applicable to the $K {\bar K}$ production at the $\phi(1020)$ resonance, where the Coulomb effect in the charged-to-neutral yield ratio is generally sensitive to the scattering phases in both the isoscalar and the isovector channels. Furthermore, we apply the same approach to the treatment of the effect of the isotopic mass difference between the charged and neutral mesons and argue that the strong-scattering effects generally result in a modification to the pure kinematical effect of this mass difference.
hep-ph/9502236
Lev F. M.
Felix M. Lev
Qualitative Consideration Of The Effect Of Binding In Deep Inelastic Scattering
6 pages, LaTeX.
null
null
null
hep-ph
null
In our recent paper (hep-ph/9501348) we argued that the Bjorken variable $x$ in deep inelastic scattering cannot be interpreted as the light cone momentum fraction $\xi$ even in the Bjorken limit and in zero order of the perturbation theory. The purpose of the present paper is to qualitatively explain this fact using only a few simplest kinematical relations.
[ { "created": "Mon, 6 Feb 1995 15:34:53 GMT", "version": "v1" } ]
2016-09-01
[ [ "Lev", "Felix M.", "" ] ]
In our recent paper (hep-ph/9501348) we argued that the Bjorken variable $x$ in deep inelastic scattering cannot be interpreted as the light cone momentum fraction $\xi$ even in the Bjorken limit and in zero order of the perturbation theory. The purpose of the present paper is to qualitatively explain this fact using only a few simplest kinematical relations.
2012.00964
Ayodele Ore
Matthew J. Dolan, Ayodele Ore
Equivariant Energy Flow Networks for Jet Tagging
20 pages, 8 figures
Phys. Rev. D 103, 074022 (2021)
10.1103/PhysRevD.103.074022
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Jet tagging techniques that make use of deep learning show great potential for improving physics analyses at colliders. One such method is the Energy Flow Network (EFN) - a recently introduced neural network architecture that represents jets as permutation-invariant sets of particle momenta while maintaining infrared and collinear safety. We develop a variant of the Energy Flow Network architecture based on the Deep Sets formalism, incorporating permutation-equivariant layers. We derive conditions under which infrared and collinear safety can be maintained, and study the performance of these networks on the canonical example of W-boson tagging. We find that equivariant Energy Flow Networks have similar performance to Particle Flow Networks, which are superior to standard EFNs. However, equivariant Particle Flow Networks suffer from convergence and overfitting issues. Finally, we study how equivariant networks sculpt the jet mass and provide some initial results on decorrelation using planing.
[ { "created": "Wed, 2 Dec 2020 04:46:27 GMT", "version": "v1" }, { "created": "Wed, 28 Apr 2021 05:26:33 GMT", "version": "v2" } ]
2021-04-29
[ [ "Dolan", "Matthew J.", "" ], [ "Ore", "Ayodele", "" ] ]
Jet tagging techniques that make use of deep learning show great potential for improving physics analyses at colliders. One such method is the Energy Flow Network (EFN) - a recently introduced neural network architecture that represents jets as permutation-invariant sets of particle momenta while maintaining infrared and collinear safety. We develop a variant of the Energy Flow Network architecture based on the Deep Sets formalism, incorporating permutation-equivariant layers. We derive conditions under which infrared and collinear safety can be maintained, and study the performance of these networks on the canonical example of W-boson tagging. We find that equivariant Energy Flow Networks have similar performance to Particle Flow Networks, which are superior to standard EFNs. However, equivariant Particle Flow Networks suffer from convergence and overfitting issues. Finally, we study how equivariant networks sculpt the jet mass and provide some initial results on decorrelation using planing.
1707.08474
Michal Praszalowicz
Michal Praszalowicz
On a possibility of baryonic exotica
6 pages, 4 figures, talk at the the 2nd Jagiellonian Symposium on Fundamental and Applied Subatomic Physics, June 3-11, 2017, Krakow, Poland. In v2 minor text corrections (version accepted for publication in Acta Physica Polonica B Proceedings Supplement)
null
10.5506/APhysPolB.48.1775
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
Models based on chiral symmetry predict pentaquarks that have relatively low masses. We briefly review both theoretical and experimental status of exotica in the light sector. Next, shall show how to extend chiral models to baryons with one heavy quark and show that one expects exotica also in this case. Finally, we interpret recently discovered by the LHCb collaboration five $\Omega^*_c$ resonances in terms of regular and exotic excitations of the ground state $\Omega_c$.
[ { "created": "Wed, 26 Jul 2017 14:45:35 GMT", "version": "v1" }, { "created": "Thu, 14 Sep 2017 14:22:27 GMT", "version": "v2" } ]
2017-11-22
[ [ "Praszalowicz", "Michal", "" ] ]
Models based on chiral symmetry predict pentaquarks that have relatively low masses. We briefly review both theoretical and experimental status of exotica in the light sector. Next, shall show how to extend chiral models to baryons with one heavy quark and show that one expects exotica also in this case. Finally, we interpret recently discovered by the LHCb collaboration five $\Omega^*_c$ resonances in terms of regular and exotic excitations of the ground state $\Omega_c$.
hep-ph/9507372
Ansgar Denner
A. Denner, S. Dittmaier and M. Strobel
Radiative Corrections to $\gamma\gamma\to t \bar t$ in the Electroweak Standard Model
22 pages, LaTeX (compressed, uuencoded), 20 figures as compressed uuencoded ps-files, complete ps-file available via anonymous ftp from ftp://ftp.physik.uni-wuerzburg.de/pub/preprint/WUE-ITP-95-017.ps
Phys.Rev.D53:44-54,1996
10.1103/PhysRevD.53.44
BI-TP 95/27, WUE-ITP-95/017
hep-ph
null
The cross-section for $\gamma\gamma\to t \bar t$ with arbitrary polarized photons is calculated within the electroweak Standard Model including the complete virtual and soft-photonic $O(\alpha)$ corrections. We present a detailed numerical discussion of the radiative corrections with particular emphasis on the purely weak corrections. These are usually of the order of 1--10\% for energies up to 1 TeV. For unpolarized or equally polarized photons they reach almost 10\% close to threshold. The large corrections cannot be traced back to a universal origin like the running of $\alpha$ or the $\rho$-parameter. Apart from the energy region around the Higgs resonance $(\gamma\gamma\to H^*\to t\bar t)$ the weak corrections are widely independent of the Higgs-boson mass.
[ { "created": "Fri, 21 Jul 1995 14:48:09 GMT", "version": "v1" } ]
2008-11-26
[ [ "Denner", "A.", "" ], [ "Dittmaier", "S.", "" ], [ "Strobel", "M.", "" ] ]
The cross-section for $\gamma\gamma\to t \bar t$ with arbitrary polarized photons is calculated within the electroweak Standard Model including the complete virtual and soft-photonic $O(\alpha)$ corrections. We present a detailed numerical discussion of the radiative corrections with particular emphasis on the purely weak corrections. These are usually of the order of 1--10\% for energies up to 1 TeV. For unpolarized or equally polarized photons they reach almost 10\% close to threshold. The large corrections cannot be traced back to a universal origin like the running of $\alpha$ or the $\rho$-parameter. Apart from the energy region around the Higgs resonance $(\gamma\gamma\to H^*\to t\bar t)$ the weak corrections are widely independent of the Higgs-boson mass.
hep-ph/0412352
Mike Berger
M. S. Berger
Spacetime Symmetry Violation
5 pages, Presented at SUSY 2003: Supersymmetry in the Desert, University of Arizona, Tucson, AZ, June 5-10, 2003
null
null
IUHET-479
hep-ph
null
Supersymmetric models with Lorentz violation can be formulated in superspace. Two theories based on the Wess-Zumino model are discussed. A compactification of superspace can be employed to understand the chiral superfield that arises in the models.
[ { "created": "Wed, 22 Dec 2004 20:15:18 GMT", "version": "v1" } ]
2007-05-23
[ [ "Berger", "M. S.", "" ] ]
Supersymmetric models with Lorentz violation can be formulated in superspace. Two theories based on the Wess-Zumino model are discussed. A compactification of superspace can be employed to understand the chiral superfield that arises in the models.
1401.4866
Javier L. Albacete
Javier L. Albacete and Cyrille Marquet
Gluon saturation and initial conditions for relativistic heavy ion collisions
72 pages and 31 figures
null
10.1016/j.ppnp.2014.01.004
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present an overview of theoretical aspects of the phenomenon of gluon saturation in high energy scattering in Quantum Chromo Dynamics. Then we review the state-of-the-art of saturation-based phenomenological approaches to the study and characterisation of the initial state of ultra-relativistic heavy ion collisions performed at RHIC and the LHC. Our review focuses mostly in the Color Glass Condensate effective theory, although we shall also discuss other approaches in parallel.
[ { "created": "Mon, 20 Jan 2014 11:44:45 GMT", "version": "v1" } ]
2015-06-18
[ [ "Albacete", "Javier L.", "" ], [ "Marquet", "Cyrille", "" ] ]
We present an overview of theoretical aspects of the phenomenon of gluon saturation in high energy scattering in Quantum Chromo Dynamics. Then we review the state-of-the-art of saturation-based phenomenological approaches to the study and characterisation of the initial state of ultra-relativistic heavy ion collisions performed at RHIC and the LHC. Our review focuses mostly in the Color Glass Condensate effective theory, although we shall also discuss other approaches in parallel.
1805.09064
Run-Hui Li
Run-Hui Li, Cai-Dian Lu
Search for doubly heavy baryon via weak decays
4 pages; to appear in the Proceedings of the 53rd Rencontres de Moriond QCD session of March 2018
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Using the factorization approach and taking into account the final state interaction, we calculate the two body non-leptonic decays of doubly heavy baryons. After comparing the semi-leptonic decays and all possible hadronic decay channels, we found some channels with large branching ratios. Taking the detection efficiency into consideration, we suggest $\Xi_{cc}^{++}$ as the first search goal and $\Xi_{cc}^{++}\to \Lambda_c^+K^-\pi^+\pi^+$ and $\Xi_{cc}^{++}\to\Xi_{c}^{+}\pi^{+}$ as the golden discovery channels with $\Lambda_c^+$ reconstructed by $pK^-\pi^+$ and $\Xi_{c}^+ \to p K^- \pi^+$, respectively.
[ { "created": "Wed, 23 May 2018 11:31:17 GMT", "version": "v1" } ]
2018-05-24
[ [ "Li", "Run-Hui", "" ], [ "Lu", "Cai-Dian", "" ] ]
Using the factorization approach and taking into account the final state interaction, we calculate the two body non-leptonic decays of doubly heavy baryons. After comparing the semi-leptonic decays and all possible hadronic decay channels, we found some channels with large branching ratios. Taking the detection efficiency into consideration, we suggest $\Xi_{cc}^{++}$ as the first search goal and $\Xi_{cc}^{++}\to \Lambda_c^+K^-\pi^+\pi^+$ and $\Xi_{cc}^{++}\to\Xi_{c}^{+}\pi^{+}$ as the golden discovery channels with $\Lambda_c^+$ reconstructed by $pK^-\pi^+$ and $\Xi_{c}^+ \to p K^- \pi^+$, respectively.
1506.05266
Rasmus Sloth Hansen
Steen Hannestad, Rasmus Sloth Hansen, Thomas Tram, Yvonne Y. Y. Wong
Active-sterile neutrino oscillations in the early Universe with full collision terms
30 pages, 7 figures
null
10.1088/1475-7516/2015/08/019
INT-PUB-15-025
hep-ph astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Sterile neutrinos are thermalised in the early Universe via oscillations with the active neutrinos for certain mixing parameters. The most detailed calculation of this thermalisation process involves the solution of the momentum-dependent quantum kinetic equations, which track the evolution of the neutrino phase space distributions. Until now the collision terms in the quantum kinetic equations have always been approximated using equilibrium distributions, but this approximation has never been checked numerically. In this work we revisit the sterile neutrino thermalisation calculation using the full collision term, and compare the results with various existing approximations in the literature. We find a better agreement than would naively be expected, but also identify some issues with these approximations that have not been appreciated previously. These include an unphysical production of neutrinos via scattering and the importance of redistributing momentum through scattering, as well as details of Pauli blocking. Finally, we devise a new approximation scheme, which improves upon some of the shortcomings of previous schemes.
[ { "created": "Wed, 17 Jun 2015 10:11:03 GMT", "version": "v1" } ]
2015-08-19
[ [ "Hannestad", "Steen", "" ], [ "Hansen", "Rasmus Sloth", "" ], [ "Tram", "Thomas", "" ], [ "Wong", "Yvonne Y. Y.", "" ] ]
Sterile neutrinos are thermalised in the early Universe via oscillations with the active neutrinos for certain mixing parameters. The most detailed calculation of this thermalisation process involves the solution of the momentum-dependent quantum kinetic equations, which track the evolution of the neutrino phase space distributions. Until now the collision terms in the quantum kinetic equations have always been approximated using equilibrium distributions, but this approximation has never been checked numerically. In this work we revisit the sterile neutrino thermalisation calculation using the full collision term, and compare the results with various existing approximations in the literature. We find a better agreement than would naively be expected, but also identify some issues with these approximations that have not been appreciated previously. These include an unphysical production of neutrinos via scattering and the importance of redistributing momentum through scattering, as well as details of Pauli blocking. Finally, we devise a new approximation scheme, which improves upon some of the shortcomings of previous schemes.
hep-ph/0211288
York Schroder
Y. Schroder (MIT)
Automatic reduction of four-loop bubbles
5 pages. Talk presented at RADCOR/Loops and Legs 2002, Kloster Banz, Germany
Nucl.Phys.Proc.Suppl. 116 (2003) 402-406
10.1016/S0920-5632(03)80208-6
MIT-CTP 3326
hep-ph
null
We give technical details about the computational strategy employed in a recently completed investigation of the four-loop QCD free energy. In particular, the reduction step from generic vacuum bubbles to master integrals is described from a practical viewpoint, for fully massive as well as QED-type integrals.
[ { "created": "Tue, 19 Nov 2002 01:46:20 GMT", "version": "v1" } ]
2009-11-07
[ [ "Schroder", "Y.", "", "MIT" ] ]
We give technical details about the computational strategy employed in a recently completed investigation of the four-loop QCD free energy. In particular, the reduction step from generic vacuum bubbles to master integrals is described from a practical viewpoint, for fully massive as well as QED-type integrals.
1605.05761
Falko Dulat
Charalampos Anastasiou, Claude Duhr, Falko Dulat, Elisabetta Furlan, Thomas Gehrmann, Franz Herzog, Achilleas Lazopoulos, Bernhard Mistlberger
CP-even scalar boson production via gluon fusion at the LHC
33 pages, 8 awesome figures
null
10.1007/JHEP09(2016)037
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In view of the searches at the LHC for scalar particle resonances in addition to the 125 GeV Higgs boson, we present the cross section for a CP-even scalar produced via gluon fusion at N3LO in perturbative QCD assuming that it couples directly to gluons in an effective theory approach. We refine our prediction by taking into account the possibility that the scalar couples to the top-quark and computing the corresponding contributions through NLO in perturbative QCD. We assess the theoretical uncertainties of the cross section due to missing higher-order QCD effects and we provide the necessary information for obtaining the cross section value and uncertainty from our results in specific scenarios beyond the Standard Model. We also give detailed results for the case of a 750 GeV scalar, which will be the subject of intense experimental studies.
[ { "created": "Wed, 18 May 2016 21:38:01 GMT", "version": "v1" } ]
2016-10-12
[ [ "Anastasiou", "Charalampos", "" ], [ "Duhr", "Claude", "" ], [ "Dulat", "Falko", "" ], [ "Furlan", "Elisabetta", "" ], [ "Gehrmann", "Thomas", "" ], [ "Herzog", "Franz", "" ], [ "Lazopoulos", "Achilleas", "" ], [ "Mistlberger", "Bernhard", "" ] ]
In view of the searches at the LHC for scalar particle resonances in addition to the 125 GeV Higgs boson, we present the cross section for a CP-even scalar produced via gluon fusion at N3LO in perturbative QCD assuming that it couples directly to gluons in an effective theory approach. We refine our prediction by taking into account the possibility that the scalar couples to the top-quark and computing the corresponding contributions through NLO in perturbative QCD. We assess the theoretical uncertainties of the cross section due to missing higher-order QCD effects and we provide the necessary information for obtaining the cross section value and uncertainty from our results in specific scenarios beyond the Standard Model. We also give detailed results for the case of a 750 GeV scalar, which will be the subject of intense experimental studies.
hep-ph/9809340
Gert Aarts
Gert Aarts (Utrecht University) and Jan Smit (University of Amsterdam, Utrecht University)
Non-Equilibrium Dynamics with Fermions on a Lattice in Space and Time
4 pages, 6 eps figures, poster presented at the 5th International Workshop on Thermal Field Theories and Their Applications, Regensburg, Germany, August 10-14, 1998. Short discussion on the large N_f limit added
null
null
null
hep-ph
null
We consider the dynamics of the 1+1 dimensional abelian Higgs model with axially coupled fermions, in the large N_f limit, on a lattice in space and real-time. We allow for inhomogeneous classical Bose fields. In order to deal with the lattice doublers, we use Wilson's lattice fermions. The lattice formulation leads to a stable integration algorithm. We demonstrate the practical implementation with numerical results.
[ { "created": "Fri, 11 Sep 1998 12:20:17 GMT", "version": "v1" }, { "created": "Thu, 12 Nov 1998 13:55:09 GMT", "version": "v2" } ]
2007-05-23
[ [ "Aarts", "Gert", "", "Utrecht University" ], [ "Smit", "Jan", "", "University of Amsterdam,\n Utrecht University" ] ]
We consider the dynamics of the 1+1 dimensional abelian Higgs model with axially coupled fermions, in the large N_f limit, on a lattice in space and real-time. We allow for inhomogeneous classical Bose fields. In order to deal with the lattice doublers, we use Wilson's lattice fermions. The lattice formulation leads to a stable integration algorithm. We demonstrate the practical implementation with numerical results.
0906.5342
Michael Ramsey-Musolf
Michael J. Ramsey-Musolf
Minimal Electroweak Scale Cosmology and the LHC
8 pages, 1 figure; proceedings of SNOWPAC 2009
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
I discuss simple extensions of the Standard Model scalar sector that can help solve the origin of matter problem and that can be probed in their cosmologically relevant parameter space at the LHC.
[ { "created": "Mon, 29 Jun 2009 19:49:32 GMT", "version": "v1" } ]
2009-06-30
[ [ "Ramsey-Musolf", "Michael J.", "" ] ]
I discuss simple extensions of the Standard Model scalar sector that can help solve the origin of matter problem and that can be probed in their cosmologically relevant parameter space at the LHC.
hep-ph/0110015
Serguei Bitioukov
S.I. Bityukov (IHEP, Protvino), N.V. Krasnikov (INR, Moscow)
LHC(CMS) SUSY discovery potential for the case of nonuniversal gaugino masses
1 latex (3 pages), 2 eps (figures) files. Presented by N.V.Krasnikov at the 9th International Conference on Supersymmetries in Physics (SUSY 01), 11-17 Jun 2001, Dubna, Russia
null
null
null
hep-ph
null
We investigate squark and gluino pair production at LHC(CMS) for the case of nonuniversal gaugino masses. Visibility of signal by an excess over SM background in $(n \geq 2)jets + E^{miss}_T + (m \geq leptons)$ events depends rather strongly on the relation between LSP, gluino and squark masses and it decreases with the increase of LSP mass. For relatively heavy LSP mass close to squark or gluino masses it is possible to detect SUSY for $(m_{\tilde{q}}, m_{\tilde{g}}) \leq (1 - 1.5)$ TeV.}
[ { "created": "Sun, 30 Sep 2001 14:33:21 GMT", "version": "v1" } ]
2007-05-23
[ [ "Bityukov", "S. I.", "", "IHEP, Protvino" ], [ "Krasnikov", "N. V.", "", "INR, Moscow" ] ]
We investigate squark and gluino pair production at LHC(CMS) for the case of nonuniversal gaugino masses. Visibility of signal by an excess over SM background in $(n \geq 2)jets + E^{miss}_T + (m \geq leptons)$ events depends rather strongly on the relation between LSP, gluino and squark masses and it decreases with the increase of LSP mass. For relatively heavy LSP mass close to squark or gluino masses it is possible to detect SUSY for $(m_{\tilde{q}}, m_{\tilde{g}}) \leq (1 - 1.5)$ TeV.}
1812.05111
Jasmine Brewer
Jasmine Brewer, Jos\'e Guilherme Milhano, Jesse Thaler
Sorting out quenched jets
5 pages, 4 figures; v2: to match journal version
Phys. Rev. Lett. 122, 222301 (2019)
10.1103/PhysRevLett.122.222301
MIT-CTP/5089
hep-ph hep-ex nucl-ex nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We introduce a new 'quantile' analysis strategy to study the modification of jets as they traverse through a droplet of quark-gluon plasma. To date, most jet modification studies have been based on comparing the jet properties measured in heavy-ion collisions to a proton-proton baseline at the same reconstructed jet transverse momentum ($p_T$). It is well known, however, that the quenching of jets from their interaction with the medium leads to a migration of jets from higher to lower $p_T$, making it challenging to directly infer the degree and mechanism of jet energy loss. Our proposed quantile matching procedure is inspired by (but not reliant on) the approximate monotonicity of energy loss in the jet $p_T$. In this strategy, jets in heavy-ion collisions ordered by $p_T$ are viewed as modified versions of the same number of highest-energy jets in proton-proton collisions, and the fractional energy loss as a function of jet $p_T$ is a natural observable ($Q_{\rm AA}$). Furthermore, despite non-monotonic fluctuations in the energy loss, we use an event generator to validate the strong correlation between the $p_T$ of the parton that initiates a heavy-ion jet and the $p_T$ of the vacuum jet which corresponds to it via the quantile procedure ($p_T^{\rm quant}$). We demonstrate that this strategy both provides a complementary way to study jet modification and mitigates the effect of $p_T$ migration in heavy-ion collisions.
[ { "created": "Wed, 12 Dec 2018 19:00:04 GMT", "version": "v1" }, { "created": "Mon, 16 Sep 2019 19:33:33 GMT", "version": "v2" } ]
2019-09-18
[ [ "Brewer", "Jasmine", "" ], [ "Milhano", "José Guilherme", "" ], [ "Thaler", "Jesse", "" ] ]
We introduce a new 'quantile' analysis strategy to study the modification of jets as they traverse through a droplet of quark-gluon plasma. To date, most jet modification studies have been based on comparing the jet properties measured in heavy-ion collisions to a proton-proton baseline at the same reconstructed jet transverse momentum ($p_T$). It is well known, however, that the quenching of jets from their interaction with the medium leads to a migration of jets from higher to lower $p_T$, making it challenging to directly infer the degree and mechanism of jet energy loss. Our proposed quantile matching procedure is inspired by (but not reliant on) the approximate monotonicity of energy loss in the jet $p_T$. In this strategy, jets in heavy-ion collisions ordered by $p_T$ are viewed as modified versions of the same number of highest-energy jets in proton-proton collisions, and the fractional energy loss as a function of jet $p_T$ is a natural observable ($Q_{\rm AA}$). Furthermore, despite non-monotonic fluctuations in the energy loss, we use an event generator to validate the strong correlation between the $p_T$ of the parton that initiates a heavy-ion jet and the $p_T$ of the vacuum jet which corresponds to it via the quantile procedure ($p_T^{\rm quant}$). We demonstrate that this strategy both provides a complementary way to study jet modification and mitigates the effect of $p_T$ migration in heavy-ion collisions.
1301.3075
Anna Stasto
C.A. Cruz-Santiago, A.M. Stasto
Gluon cascades and amplitudes in light-front perturbation theory
25 pages, 15 figures
null
10.1016/j.nuclphysb.2012.12.003
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We construct the gluon wave functions, fragmentation functions and scattering amplitudes within the light-front perturbation theory. Recursion relations on the light-front are constructed for the wave functions and fragmentation functions, which in the latter case are the light-front analogs of the Berends-Giele recursion relations. Using general relations between wave functions and scattering amplitudes it is demonstrated how to obtain the maximally-helicity violating amplitudes, and explicit verification of the results is based on simple examples.
[ { "created": "Mon, 14 Jan 2013 17:51:33 GMT", "version": "v1" } ]
2015-06-12
[ [ "Cruz-Santiago", "C. A.", "" ], [ "Stasto", "A. M.", "" ] ]
We construct the gluon wave functions, fragmentation functions and scattering amplitudes within the light-front perturbation theory. Recursion relations on the light-front are constructed for the wave functions and fragmentation functions, which in the latter case are the light-front analogs of the Berends-Giele recursion relations. Using general relations between wave functions and scattering amplitudes it is demonstrated how to obtain the maximally-helicity violating amplitudes, and explicit verification of the results is based on simple examples.
1810.12234
Satoshi Shirai
Shigeki Matsumoto, Satoshi Shirai and Michihisa Takeuchi
Indirect Probe of Electroweak-Interacting Particles with Mono-Lepton Signatures at Hadron Colliders
10 pages, 7 figures
null
null
IPMU18-0176
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Electroweak-interacting massive particles (EWIMPs) exist in a broad class of new physics models beyond the Standard Model. Searching for such particles is one of most primary goal at the LHC and future colliders. The EWIMP generally affects the LHC signatures through quantum corrections even without direct productions. By measuring the Standard Model processes precisely, we can indirectly probe the EWIMPs. In this paper, we study the current constraint and future prospect of the EWIMPs by using the precision measurements of mono-lepton production from the charged Drell-Yan processes at hadron colliders. We found the mono-lepton signature can be a better probe than dilepton signature from the neutral Drell-Yan processes.
[ { "created": "Mon, 29 Oct 2018 16:23:10 GMT", "version": "v1" } ]
2018-10-30
[ [ "Matsumoto", "Shigeki", "" ], [ "Shirai", "Satoshi", "" ], [ "Takeuchi", "Michihisa", "" ] ]
Electroweak-interacting massive particles (EWIMPs) exist in a broad class of new physics models beyond the Standard Model. Searching for such particles is one of most primary goal at the LHC and future colliders. The EWIMP generally affects the LHC signatures through quantum corrections even without direct productions. By measuring the Standard Model processes precisely, we can indirectly probe the EWIMPs. In this paper, we study the current constraint and future prospect of the EWIMPs by using the precision measurements of mono-lepton production from the charged Drell-Yan processes at hadron colliders. We found the mono-lepton signature can be a better probe than dilepton signature from the neutral Drell-Yan processes.
hep-ph/9701367
Institute for Theoretical Physics
Jin-Ping Li, Mu-Lin Yan and Rong-Hua Yu(UTSC)
Higher Order Perturbation Corrections of Rotating Excited States in the Standard SU(3) Skyrme Model to Baryon Mass Spectrum
LateX file, 21 pages, no figures
Int.J.Mod.Phys. A12 (1997) 873-890
10.1142/S0217751X97000669
NSC/USTC-17/96
hep-ph
null
The higher order corrections of SU(3) rotating excited states to the Gell-Mann-Okubo Relations (or GOR) are presented in the standard SU(3) Skyrme model.The Improved GOR (or IGOR) are obtained. The results show the IGOR for decuplet up to the third order and for octet up to the second order are much compatible with the experimental data. But things becomes quite inadequate for the octet to the third order. In order to overcome the inadequacy, a heuristic discussion is presented. The properties of SU(3) rotating excited states 27-let(with spin 1/2 or 3/2),10$^*$-let (with spin 1/2) and 35-let (with spin 3/2) are also discussed.
[ { "created": "Fri, 24 Jan 1997 11:11:54 GMT", "version": "v1" } ]
2015-06-25
[ [ "Li", "Jin-Ping", "", "UTSC" ], [ "Yan", "Mu-Lin", "", "UTSC" ], [ "Yu", "Rong-Hua", "", "UTSC" ] ]
The higher order corrections of SU(3) rotating excited states to the Gell-Mann-Okubo Relations (or GOR) are presented in the standard SU(3) Skyrme model.The Improved GOR (or IGOR) are obtained. The results show the IGOR for decuplet up to the third order and for octet up to the second order are much compatible with the experimental data. But things becomes quite inadequate for the octet to the third order. In order to overcome the inadequacy, a heuristic discussion is presented. The properties of SU(3) rotating excited states 27-let(with spin 1/2 or 3/2),10$^*$-let (with spin 1/2) and 35-let (with spin 3/2) are also discussed.
1411.1363
Kirill Tuchin
Kirill Tuchin
Electromagnetic field and the chiral magnetic effect in the quark-gluon plasma
13 pages, 3 figures; v2: improved presentation, typos fixed, v3: a mistake in Eq. (62) is fixed
Phys. Rev. C 91, 064902 (2015)
10.1103/PhysRevC.91.064902
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Time evolution of electromagnetic field created in heavy-ion collisions strongly depends on the electromagnetic response of the quark-gluon plasma, which can be described by the Ohmic and chiral conductivities. The later is intimately related to the Chiral Magnetic Effect. I argue that a solution to the classical Maxwell equations at finite chiral conductivity is unstable due to the soft modes $k<\sigma_\chi$ that grow exponentially with time. In the kinematical region relevant for the relativistic heavy-ion collisions, I derive analytical expressions for the magnetic field of a point charge. I show that finite chiral conductivity causes oscillations of magnetic field at early times.
[ { "created": "Wed, 5 Nov 2014 19:18:05 GMT", "version": "v1" }, { "created": "Wed, 13 May 2015 13:56:44 GMT", "version": "v2" }, { "created": "Tue, 8 Mar 2016 21:30:08 GMT", "version": "v3" } ]
2016-03-10
[ [ "Tuchin", "Kirill", "" ] ]
Time evolution of electromagnetic field created in heavy-ion collisions strongly depends on the electromagnetic response of the quark-gluon plasma, which can be described by the Ohmic and chiral conductivities. The later is intimately related to the Chiral Magnetic Effect. I argue that a solution to the classical Maxwell equations at finite chiral conductivity is unstable due to the soft modes $k<\sigma_\chi$ that grow exponentially with time. In the kinematical region relevant for the relativistic heavy-ion collisions, I derive analytical expressions for the magnetic field of a point charge. I show that finite chiral conductivity causes oscillations of magnetic field at early times.
1912.01435
HongWei Ke
Hong-Wei Ke, Fang Lu, Xiao-Hai Liu and Xue-Qian Li
Study on $\Xi_{cc}\to\Xi_c$ and $\Xi_{cc}\to\Xi'_c$ weak decays in the light-front quark model
18 pages, 4 firures. arXiv admin note: text overlap with arXiv:1904.05705
Eur.Phys.J. C80 (2020) no.2, 140
10.1140/epjc/s10052-020-7699-y
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this work we study the weak decays of $\Xi_{cc}\to\Xi_c$ and $\Xi_{cc}\to\Xi'_c$ in the light-front quark model. Generally, a naive, but reasonable conjecture suggests that the $cc$ subsystem in $\Xi_{cc}$ ( $us$ pair in $\Xi^{(')}_c$) stands as a diquark with definite spin and color assignments. During the concerned processes, the diquark of the initial state is not a spectator, and must be broken. A Racah transformation would decompose the original $(cc)q$ into a combination of $c(cq)$ components. Thus we may deal with the decaying $c$ quark alone while keeping the $(cq)$ subsystem as a spectator. With the re-arrangement of the inner structure we calculate the form factors numerically and then obtain the rates of semi-leptonic decays and non-leptonic decays, which will be measured in the future.
[ { "created": "Mon, 2 Dec 2019 15:10:02 GMT", "version": "v1" } ]
2020-03-17
[ [ "Ke", "Hong-Wei", "" ], [ "Lu", "Fang", "" ], [ "Liu", "Xiao-Hai", "" ], [ "Li", "Xue-Qian", "" ] ]
In this work we study the weak decays of $\Xi_{cc}\to\Xi_c$ and $\Xi_{cc}\to\Xi'_c$ in the light-front quark model. Generally, a naive, but reasonable conjecture suggests that the $cc$ subsystem in $\Xi_{cc}$ ( $us$ pair in $\Xi^{(')}_c$) stands as a diquark with definite spin and color assignments. During the concerned processes, the diquark of the initial state is not a spectator, and must be broken. A Racah transformation would decompose the original $(cc)q$ into a combination of $c(cq)$ components. Thus we may deal with the decaying $c$ quark alone while keeping the $(cq)$ subsystem as a spectator. With the re-arrangement of the inner structure we calculate the form factors numerically and then obtain the rates of semi-leptonic decays and non-leptonic decays, which will be measured in the future.
1512.02229
Marc Thomas Dr
Alexander Belyaev, Stefano Moretti, Kilian Nickel, Marc C. Thomas, Ian Tomalin
Hunting for neutral, long-lived exotica at the LHC using a missing transverse energy signature
28 pages
null
10.1007/JHEP03(2016)018
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Searches at the Large Hadron Collider (LHC) for neutral, long-lived particles have historically relied on the detection of displaced particles produced by their decay $\textit{within}$ the detector volume. In this paper we study the potential of the complementary signature comprising of the missing transverse energy ($E_T^{miss}$) signal, traditionally used to look for dark matter, e.g., the lightest supersymmetric particle (LSP), to extend the LHC coverage to models with long-lived (LL) particles when they decay $\textit{outside}$ the detector. Using CMS and ATLAS analyses at the 8 TeV LHC, we set an upper limit at the 95% confidence level (CL) on the production cross sections for two specific scenarios: (i) a model with a heavy non-standard model Higgs boson decaying to a LL scalar and (ii) an R-parity violating RPV SUSY model with a LL neutralino. We show that this method can significantly extend the LHC sensitivity to neutral, LL particles with arbitrary large lifetimes and that the limits obtained from a $E_T^{miss}$ signal are comparable to those from displaced particle searches for decay distances above a few meters. Results obtained in this study do not not depend on the specific decay channel of the LL particle and therefore are model-independent in this sense. We provide limits for the whole two-dimensional plane in terms of the mass of the LL particle and the mass of the mediator up to masses of 2 TeV including particular benchmarks studied in the original experimental papers. We have made these limits available in the form of a grid which can be used for the interpretation of various other new physics models.
[ { "created": "Mon, 7 Dec 2015 21:00:04 GMT", "version": "v1" } ]
2016-03-23
[ [ "Belyaev", "Alexander", "" ], [ "Moretti", "Stefano", "" ], [ "Nickel", "Kilian", "" ], [ "Thomas", "Marc C.", "" ], [ "Tomalin", "Ian", "" ] ]
Searches at the Large Hadron Collider (LHC) for neutral, long-lived particles have historically relied on the detection of displaced particles produced by their decay $\textit{within}$ the detector volume. In this paper we study the potential of the complementary signature comprising of the missing transverse energy ($E_T^{miss}$) signal, traditionally used to look for dark matter, e.g., the lightest supersymmetric particle (LSP), to extend the LHC coverage to models with long-lived (LL) particles when they decay $\textit{outside}$ the detector. Using CMS and ATLAS analyses at the 8 TeV LHC, we set an upper limit at the 95% confidence level (CL) on the production cross sections for two specific scenarios: (i) a model with a heavy non-standard model Higgs boson decaying to a LL scalar and (ii) an R-parity violating RPV SUSY model with a LL neutralino. We show that this method can significantly extend the LHC sensitivity to neutral, LL particles with arbitrary large lifetimes and that the limits obtained from a $E_T^{miss}$ signal are comparable to those from displaced particle searches for decay distances above a few meters. Results obtained in this study do not not depend on the specific decay channel of the LL particle and therefore are model-independent in this sense. We provide limits for the whole two-dimensional plane in terms of the mass of the LL particle and the mass of the mediator up to masses of 2 TeV including particular benchmarks studied in the original experimental papers. We have made these limits available in the form of a grid which can be used for the interpretation of various other new physics models.
1807.01955
Stephen Webster
Peter Richardson and Stephen Webster
Spin Correlations in Parton Shower Simulations
13 pages, 12 figures, 3 tables
null
null
CERN-TH-2018-154, IPPP/18/55, MCnet-18-12
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Spin correlations are an important, but often neglected, effect in modern Monte Carlo event generators. We show that they can be fully incorporated in Herwig 7 using the algorithm originally proposed by Collins and Knowles in all stages of the event generation process and between the different stages of the event generation. In this paper we present the final missing ingredient, correlations in both the angular-ordered and dipole shower algorithms and between the parton shower and hard production and decay processes.
[ { "created": "Thu, 5 Jul 2018 12:07:12 GMT", "version": "v1" } ]
2018-07-06
[ [ "Richardson", "Peter", "" ], [ "Webster", "Stephen", "" ] ]
Spin correlations are an important, but often neglected, effect in modern Monte Carlo event generators. We show that they can be fully incorporated in Herwig 7 using the algorithm originally proposed by Collins and Knowles in all stages of the event generation process and between the different stages of the event generation. In this paper we present the final missing ingredient, correlations in both the angular-ordered and dipole shower algorithms and between the parton shower and hard production and decay processes.
0803.2102
Xianhui Zhong
Xian-hui Zhong, Qiang Zhao
Strong decays of heavy-light mesons in a chiral quark model
14 pages, 6 figures,to appear in PRD
Phys.Rev.D78:014029,2008
10.1103/PhysRevD.78.014029
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We carry out a systematic study of the heavy-light meson strong decays in a chiral quark model. For the $S$-wave vectors ($D^*(2007)$, $D^{*\pm}(2010)$), $P$-wave scalars ($D^*_0(2400)$, $B^*_0(5730)$) and tensors ($D^*_2(2460)$, $D^*_{s2}(2573)$), we obtain results in good agreement with the experimental data. For the axial vectors $D_1(2420)$ and $D_1^\prime(2430)$, a state mixing scheme between $1^1P_1$ and $1^3P_1$ is favored with a mixing angle $\phi\simeq-(55\pm 5)^\circ$, which is consistent with previous theoretical predictions. The same mixing scheme also applies to $D_{s1}(2460)$ and $D_{s1}(2536)$ that accounts for the narrow width of the $D_{s1}(2536)$ and its dominant decay into $D^*K$. For $B_1(5725)$ and $B_1^\prime(5732)$, such a mixing explains well the decay width of the former but leads to an even broader $B_1^\prime(5732)$. Predictions for the strange-bottom axial vectors are also made. For the undetermined meson $D^*(2640)$, we find that they fit in well the radially excited state $2^3S_1$ according to its decay mode. The newly observed $D^*_{sJ}(2860)$ strongly favors the $D$-wave excited state $1^3D_3$. For $D^*_{sJ}(2632)$ and $D^*_{sJ}(2690)$, we find they are difficult to fit in any $D_s$ excitations in that mass region, if the experimental data are accurate. Theoretical predictions for decay modes of those unobserved states as multiplets of 2S and 1D waves are also presented, which should be useful for further experimental search for those states.
[ { "created": "Fri, 14 Mar 2008 08:13:39 GMT", "version": "v1" }, { "created": "Sat, 28 Jun 2008 01:48:28 GMT", "version": "v2" } ]
2008-11-26
[ [ "Zhong", "Xian-hui", "" ], [ "Zhao", "Qiang", "" ] ]
We carry out a systematic study of the heavy-light meson strong decays in a chiral quark model. For the $S$-wave vectors ($D^*(2007)$, $D^{*\pm}(2010)$), $P$-wave scalars ($D^*_0(2400)$, $B^*_0(5730)$) and tensors ($D^*_2(2460)$, $D^*_{s2}(2573)$), we obtain results in good agreement with the experimental data. For the axial vectors $D_1(2420)$ and $D_1^\prime(2430)$, a state mixing scheme between $1^1P_1$ and $1^3P_1$ is favored with a mixing angle $\phi\simeq-(55\pm 5)^\circ$, which is consistent with previous theoretical predictions. The same mixing scheme also applies to $D_{s1}(2460)$ and $D_{s1}(2536)$ that accounts for the narrow width of the $D_{s1}(2536)$ and its dominant decay into $D^*K$. For $B_1(5725)$ and $B_1^\prime(5732)$, such a mixing explains well the decay width of the former but leads to an even broader $B_1^\prime(5732)$. Predictions for the strange-bottom axial vectors are also made. For the undetermined meson $D^*(2640)$, we find that they fit in well the radially excited state $2^3S_1$ according to its decay mode. The newly observed $D^*_{sJ}(2860)$ strongly favors the $D$-wave excited state $1^3D_3$. For $D^*_{sJ}(2632)$ and $D^*_{sJ}(2690)$, we find they are difficult to fit in any $D_s$ excitations in that mass region, if the experimental data are accurate. Theoretical predictions for decay modes of those unobserved states as multiplets of 2S and 1D waves are also presented, which should be useful for further experimental search for those states.
hep-ph/9803270
Juan Garcia-Bellido
Juan Garcia-Bellido (CERN-TH)
Single-bubble Open Inflation: An Overview
20 pages, LaTeX, crckapb.sty macro included, 6 figures included in the text with epsf. Review talk, to appear in the Proceedings of the ``Birth of the Universe II'' Conference in Roma, May 1997
null
null
CERN-TH/98-13
hep-ph astro-ph
null
The idea that the universe might be open is an old one, and the possibility of having an open universe arise form inflation is not new either. However, a concrete realization of a consistent single-bubble open inflation model is known only recently. There has been great progress in the last two years in the development of models of inflation consistent with observations in such an open universe. In this overview I will describe the basic features and the phenomenological consequences of such models, making emphasis in the predictions of the CMB temperature anisotropies that differ from ordinary inflation.
[ { "created": "Fri, 6 Mar 1998 14:33:25 GMT", "version": "v1" } ]
2007-05-23
[ [ "Garcia-Bellido", "Juan", "", "CERN-TH" ] ]
The idea that the universe might be open is an old one, and the possibility of having an open universe arise form inflation is not new either. However, a concrete realization of a consistent single-bubble open inflation model is known only recently. There has been great progress in the last two years in the development of models of inflation consistent with observations in such an open universe. In this overview I will describe the basic features and the phenomenological consequences of such models, making emphasis in the predictions of the CMB temperature anisotropies that differ from ordinary inflation.
hep-ph/0212302
Manuel Malheiro
A. Delfino (1), J. B. da Silva (1), M. Malheiro (1), M. Chiapparini (2) and M. E. Bracco (2) ((1)Instituto de Fisica, UFF, Niteroi, Brazil (2) Instituto de Fisica, UERJ, Rio de Janeiro, Brazil)
Hadronic Entropy Enhancement and Low Density QGP
null
J.Phys.G28:2249-2258,2002
10.1088/0954-3899/28/8/310
null
hep-ph
null
Recent studies show that for central collisions the rising of the incident energy from AGS to RHIC decreases the value of the chemical potential in the Hadron-QGP phase diagram. Thus, the formation of QGP at RHIC energies in central collisions may be expected to occur at very small values of the chemical potential. Using many different relativistic mean-field hadronic models (RMF) at this regime we show that the critical temperature for the Hadron-QGP transition is hadronic model independent. We have traced back the reason for this and conclude that it comes from the fact that the QGP entropy is much larger than the hadronic entropy obtained in all the RMF models. We also find that almost all of these models present a strong entropy enhancement in the hadronic sector coming from the baryonic phase transition to a nucleon-antinucleon plasma. This result is in agreement with the recent data obtained in the STAR collaboration at RHIC where it was found a rich proton-antiproton matter.
[ { "created": "Thu, 19 Dec 2002 19:31:05 GMT", "version": "v1" } ]
2008-11-26
[ [ "Delfino", "A.", "" ], [ "da Silva", "J. B.", "" ], [ "Malheiro", "M.", "" ], [ "Chiapparini", "M.", "" ], [ "Bracco", "M. E.", "" ] ]
Recent studies show that for central collisions the rising of the incident energy from AGS to RHIC decreases the value of the chemical potential in the Hadron-QGP phase diagram. Thus, the formation of QGP at RHIC energies in central collisions may be expected to occur at very small values of the chemical potential. Using many different relativistic mean-field hadronic models (RMF) at this regime we show that the critical temperature for the Hadron-QGP transition is hadronic model independent. We have traced back the reason for this and conclude that it comes from the fact that the QGP entropy is much larger than the hadronic entropy obtained in all the RMF models. We also find that almost all of these models present a strong entropy enhancement in the hadronic sector coming from the baryonic phase transition to a nucleon-antinucleon plasma. This result is in agreement with the recent data obtained in the STAR collaboration at RHIC where it was found a rich proton-antiproton matter.
hep-ph/0112185
Johann Rafelski
Johann Rafelski (Arizona and CERN)
Strangeness, Equilibration, Hadronization
8 pages including one figure, discussion contribution at Strange Quark Matter 2001, Frankfurt, submitted to J. Phys. G
J.Phys.G28:1833-1840,2002
10.1088/0954-3899/28/7/337
CERN-TH/2001-364
hep-ph
null
In these remarks I explain the motivation which leads us to consider chemical nonequilibrium processes in flavor equilibration and in statistical hadroniziation of quark--gluon plasma (QGP). Statistical hadronization allowing for chemical non-equilibrium is introduced. The reesults of fits to RHIC-130 results, including multistrange hadrons, are shown to agree only with the model of an exploding QGP fireball.
[ { "created": "Thu, 13 Dec 2001 17:17:14 GMT", "version": "v1" } ]
2016-09-06
[ [ "Rafelski", "Johann", "", "Arizona and CERN" ] ]
In these remarks I explain the motivation which leads us to consider chemical nonequilibrium processes in flavor equilibration and in statistical hadroniziation of quark--gluon plasma (QGP). Statistical hadronization allowing for chemical non-equilibrium is introduced. The reesults of fits to RHIC-130 results, including multistrange hadrons, are shown to agree only with the model of an exploding QGP fireball.
1108.4932
Mehrdad Goshtasbpour
M. Goshtasbpour, M. Zandi
II. Non-commuting Matrix Solution of DGLAP; $F_2 {p,d}$ Data Leading to Partons Directly without Parameterization
7 pages, 8 figures
null
null
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Dominant present path for determination of quarks and gluon distribution functions from data is based on pre-assumed form of parameters. Here, an alternative direct, or non-parametric method is spelled out. As the main task, least square estimates of the central values are obtained at the exact $x$ points of the analysed ${{F_2}^{p,d}}$ data points, at a chosen $Q^2$. In the process, numerically singular system of weighted linear combination of LO decomposition equations of the data points, each at a given $(x_k, {Q_{kl}}^2), l=1, ..., n_k$, obtained from a respective $\chi^2$, together with the equations of Zero Mass Variable Flavour Number constraints, are solved. In each data equation, the corresponding data points are decomposed into their quarks and gluon components, evolved from a set of unknowns at $(x_k, Q^2), k=1, ..., n$. A similar evolution is done in the constraints. As a complementary task, the constrained discrete $x$ set, required for the commuting solution of evolution equation, \cite{I}, is relaxed, and a non-commuting solution on a more natural set of exact $x$ points of the data is developed.
[ { "created": "Wed, 24 Aug 2011 20:04:03 GMT", "version": "v1" }, { "created": "Wed, 11 Sep 2013 17:57:23 GMT", "version": "v2" } ]
2013-09-12
[ [ "Goshtasbpour", "M.", "" ], [ "Zandi", "M.", "" ] ]
Dominant present path for determination of quarks and gluon distribution functions from data is based on pre-assumed form of parameters. Here, an alternative direct, or non-parametric method is spelled out. As the main task, least square estimates of the central values are obtained at the exact $x$ points of the analysed ${{F_2}^{p,d}}$ data points, at a chosen $Q^2$. In the process, numerically singular system of weighted linear combination of LO decomposition equations of the data points, each at a given $(x_k, {Q_{kl}}^2), l=1, ..., n_k$, obtained from a respective $\chi^2$, together with the equations of Zero Mass Variable Flavour Number constraints, are solved. In each data equation, the corresponding data points are decomposed into their quarks and gluon components, evolved from a set of unknowns at $(x_k, Q^2), k=1, ..., n$. A similar evolution is done in the constraints. As a complementary task, the constrained discrete $x$ set, required for the commuting solution of evolution equation, \cite{I}, is relaxed, and a non-commuting solution on a more natural set of exact $x$ points of the data is developed.
hep-ph/0702271
Junli Li
Yi-Bing Ding, Junli Li, Cong-Feng Qiao
Bell Inequalities in High Energy Physics
26 pages, 3 eps figures; references added, published version
High Ener. Phys. & Nucl. Phys. 31, 1086(2007)
null
GUCAS-CPS-07-03
hep-ph quant-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We review in this paper the research status on testing the completeness of Quantum mechanics in High Energy Physics, especially on the Bell Inequalities. We briefly introduce the basic idea of Einstein, Podolsky, and Rosen paradox and the results obtained in photon experiments. In the tests of Bell inequalities in high energy physics, the early attempts of using spin correlations in particle decays and later on the mixing of neutral mesons used to form the quasi-spin entangled states are covered. The related experimental results in K^0 and B^0 systems are presented and discussed. We introduce the new scheme, which is based on the non-maximally entangled state and proposed to implement in \phi factory, in testing the Local Hidden Variable Theory. And, we also discuss the possibility in generalizing it to the tau charm factory.
[ { "created": "Tue, 27 Feb 2007 06:54:06 GMT", "version": "v1" }, { "created": "Sat, 4 Apr 2009 03:25:06 GMT", "version": "v2" } ]
2009-04-04
[ [ "Ding", "Yi-Bing", "" ], [ "Li", "Junli", "" ], [ "Qiao", "Cong-Feng", "" ] ]
We review in this paper the research status on testing the completeness of Quantum mechanics in High Energy Physics, especially on the Bell Inequalities. We briefly introduce the basic idea of Einstein, Podolsky, and Rosen paradox and the results obtained in photon experiments. In the tests of Bell inequalities in high energy physics, the early attempts of using spin correlations in particle decays and later on the mixing of neutral mesons used to form the quasi-spin entangled states are covered. The related experimental results in K^0 and B^0 systems are presented and discussed. We introduce the new scheme, which is based on the non-maximally entangled state and proposed to implement in \phi factory, in testing the Local Hidden Variable Theory. And, we also discuss the possibility in generalizing it to the tau charm factory.
0706.1026
Dmitri Kharzeev
D. Kharzeev and A. Zhitnitsky
Charge separation induced by P-odd bubbles in QCD matter
9 pages, 1 figure; extended discussion of cosmological and astrophysical implications; final version to appear in Nuclear Physics A
Nucl.Phys.A797:67-79,2007
10.1016/j.nuclphysa.2007.10.001
BNL-NT-07/24
hep-ph astro-ph hep-th nucl-ex nucl-th
null
We examine the recent suggestion that P- and CP-odd effects in QCD matter can induce electric charge asymmetry with respect to reaction plane in relativistic heavy ion collisions. General arguments are given which confirm that the angular momentum of QCD matter in the presence of non-zero topological charge should induce an electric field aligned along the axis of the angular momentum. A simple formula relating the magnitude of charge asymmetry to the angular momentum and topological charge is derived. The expected asymmetry is amenable to experimental observation at RHIC and LHC; we discuss the recent preliminary STAR result in light of our findings.
[ { "created": "Thu, 7 Jun 2007 15:38:18 GMT", "version": "v1" }, { "created": "Mon, 1 Oct 2007 18:08:30 GMT", "version": "v2" } ]
2008-11-26
[ [ "Kharzeev", "D.", "" ], [ "Zhitnitsky", "A.", "" ] ]
We examine the recent suggestion that P- and CP-odd effects in QCD matter can induce electric charge asymmetry with respect to reaction plane in relativistic heavy ion collisions. General arguments are given which confirm that the angular momentum of QCD matter in the presence of non-zero topological charge should induce an electric field aligned along the axis of the angular momentum. A simple formula relating the magnitude of charge asymmetry to the angular momentum and topological charge is derived. The expected asymmetry is amenable to experimental observation at RHIC and LHC; we discuss the recent preliminary STAR result in light of our findings.
hep-ph/0410074
Piet Mulders J.
P.J. Mulders and P. Jimenez Delgado
The Uniqueness of the $\Theta^+$ Pentaquark
6 pages, 5 figures, 19th European Few Body Conference
null
10.1063/1.1932909
null
hep-ph
null
The existence of the $\Theta^+$ pentaquark requires a peculiar mechanism to explain its stability. Looking at quark clusters, notably diquark and triquark configurations, such a mechanism may be found in the color-magnetic interaction between quarks. It is possible to understand why the $\Theta^+$ is unique. Chiral dynamics, in particular the ease of pion emission, will render other members of the same flavor antidecuplet, such as the $\Xi^{--}$ very unstable.
[ { "created": "Tue, 5 Oct 2004 16:00:54 GMT", "version": "v1" } ]
2009-11-10
[ [ "Mulders", "P. J.", "" ], [ "Delgado", "P. Jimenez", "" ] ]
The existence of the $\Theta^+$ pentaquark requires a peculiar mechanism to explain its stability. Looking at quark clusters, notably diquark and triquark configurations, such a mechanism may be found in the color-magnetic interaction between quarks. It is possible to understand why the $\Theta^+$ is unique. Chiral dynamics, in particular the ease of pion emission, will render other members of the same flavor antidecuplet, such as the $\Xi^{--}$ very unstable.
1707.02075
David Chinellato D
R. Acconcia, D.D. Chinellato, R. Derradi de Souza, C. Markert, J. Takahashi, G. Torrieri
Color reconnection effects on resonance production
15 pages, 8 captioned figures
Phys. Rev. D 97, 036010 (2018)
10.1103/PhysRevD.97.036010
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present studies that show how multi-parton interaction and color reconnection affect the hadro-chemistry in proton-proton (pp) collisions with special focus on the production of resonances using the PYTHIA8 event generator. We find that color reconnection suppresses the relative production of meson resonances such as $\rho_{0}$ and K*, providing an alternative explanation for the K*/K decrease observed in proton-proton collisions as a function of multiplicity by the ALICE collaboration. Detailed studies of the underlying mechanism causing meson resonance suppression indicate that color reconnection leads to shorter, less energetic strings whose fragmentation is less likely to produce more massive hadrons for a given quark content, therefore reducing ratios such as K*/K and $\rho_0/\pi$ in high-multiplicity pp collisions. In addition, we have also studied the effects of allowing string junctions to form and found that these may also contribute to resonance suppression.
[ { "created": "Fri, 7 Jul 2017 08:34:14 GMT", "version": "v1" }, { "created": "Fri, 3 Nov 2017 12:12:41 GMT", "version": "v2" }, { "created": "Wed, 24 Jan 2018 13:10:20 GMT", "version": "v3" } ]
2018-02-21
[ [ "Acconcia", "R.", "" ], [ "Chinellato", "D. D.", "" ], [ "de Souza", "R. Derradi", "" ], [ "Markert", "C.", "" ], [ "Takahashi", "J.", "" ], [ "Torrieri", "G.", "" ] ]
We present studies that show how multi-parton interaction and color reconnection affect the hadro-chemistry in proton-proton (pp) collisions with special focus on the production of resonances using the PYTHIA8 event generator. We find that color reconnection suppresses the relative production of meson resonances such as $\rho_{0}$ and K*, providing an alternative explanation for the K*/K decrease observed in proton-proton collisions as a function of multiplicity by the ALICE collaboration. Detailed studies of the underlying mechanism causing meson resonance suppression indicate that color reconnection leads to shorter, less energetic strings whose fragmentation is less likely to produce more massive hadrons for a given quark content, therefore reducing ratios such as K*/K and $\rho_0/\pi$ in high-multiplicity pp collisions. In addition, we have also studied the effects of allowing string junctions to form and found that these may also contribute to resonance suppression.
1809.00199
Leonard S. Kisslinger
Leonard S. Kisslinger, Bijit Singha
Charmed Baryon Decay to a Strange Baryon Plus a Pion Using QCD Sum Rules
13 pages, 3 figures
Int.J.Mod.Phys.A 34, 1950015 (2019)
10.1142/S0217751X19500155
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This is an extension of the prediction of strange baryon decays to the decays of charmed baryons using QCD Sum Rules. Using QCD Sum Rules we estimate the decay $\Lambda^+_c (udc) \rightarrow \Lambda^o_s(uds)+ \pi^+$. Although some weak decays of the $\Lambda^+_c$ have been measured, since it is difficult to measure $\Lambda^+_c \rightarrow \Lambda^o_s+ \pi^+$ our estimates should be useful for future experiments
[ { "created": "Sat, 1 Sep 2018 14:48:46 GMT", "version": "v1" }, { "created": "Fri, 14 Sep 2018 14:47:34 GMT", "version": "v2" }, { "created": "Wed, 19 Sep 2018 15:07:05 GMT", "version": "v3" }, { "created": "Fri, 11 Jan 2019 16:04:15 GMT", "version": "v4" }, { "created": "Thu, 21 Feb 2019 16:11:18 GMT", "version": "v5" } ]
2019-02-22
[ [ "Kisslinger", "Leonard S.", "" ], [ "Singha", "Bijit", "" ] ]
This is an extension of the prediction of strange baryon decays to the decays of charmed baryons using QCD Sum Rules. Using QCD Sum Rules we estimate the decay $\Lambda^+_c (udc) \rightarrow \Lambda^o_s(uds)+ \pi^+$. Although some weak decays of the $\Lambda^+_c$ have been measured, since it is difficult to measure $\Lambda^+_c \rightarrow \Lambda^o_s+ \pi^+$ our estimates should be useful for future experiments
1401.0653
Jayanta Sarma Kumar
Mayuri Devee and J. K. Sarma
Nonlinear GLR-MQ evolution equation and Q^2-evolution of gluon distribution function
23 pages, 6 figures, 5th paragraph of introduction has been slightly changed. arXiv admin note: text overlap with arXiv:hep-ph/0211239, arXiv:hep-ph/9902411 by other authors
Eur. Phys. J. C (2014) 74:2751
10.1140/epjc/s10052-014-2751-4
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper we have solved the nonlinear Gribov-Levin-Ryskin-Mueller-Qiu (GLR-MQ) evolution equation for gluon distribution function G(x,Q^2) and studied the effects of the nonlinear GLR-MQ corrections to the Leading Order (LO) Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution equations. Here we incorporate a Regge like behaviour of gluon distribution function to obtain the solution of GLR-MQ evolution equation. We have also investigated the Q^2-dependence of gluon distribution function from the solution of GLR-MQ evolution equation. Moreover it is interesting to observe from our results that nonlinearities increase with decreasing correlation radius (R) between two interacting gluons. Results also confirm that the steep behavior of gluon distribution function is observed at R=5 GeV^{-1}, whereas it is lowered at R=2 GeV^{-1} with decreasing x as Q^2 increases. In this work we have also checked the sensitivity of \lambda_G in our calculations. Our computed results are compared with those obtained by the global DGLAP fits to the parton distribution functions viz. GRV, MRST, MSTW and with the EHKQS model.
[ { "created": "Fri, 3 Jan 2014 14:15:59 GMT", "version": "v1" }, { "created": "Mon, 6 Jan 2014 07:37:05 GMT", "version": "v2" }, { "created": "Fri, 21 Feb 2014 10:34:15 GMT", "version": "v3" } ]
2014-02-24
[ [ "Devee", "Mayuri", "" ], [ "Sarma", "J. K.", "" ] ]
In this paper we have solved the nonlinear Gribov-Levin-Ryskin-Mueller-Qiu (GLR-MQ) evolution equation for gluon distribution function G(x,Q^2) and studied the effects of the nonlinear GLR-MQ corrections to the Leading Order (LO) Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution equations. Here we incorporate a Regge like behaviour of gluon distribution function to obtain the solution of GLR-MQ evolution equation. We have also investigated the Q^2-dependence of gluon distribution function from the solution of GLR-MQ evolution equation. Moreover it is interesting to observe from our results that nonlinearities increase with decreasing correlation radius (R) between two interacting gluons. Results also confirm that the steep behavior of gluon distribution function is observed at R=5 GeV^{-1}, whereas it is lowered at R=2 GeV^{-1} with decreasing x as Q^2 increases. In this work we have also checked the sensitivity of \lambda_G in our calculations. Our computed results are compared with those obtained by the global DGLAP fits to the parton distribution functions viz. GRV, MRST, MSTW and with the EHKQS model.
1611.01104
Arnd Behring
Jakob Ablinger, Arnd Behring, Johannes Bl\"umlein, Abilio De Freitas, Alexander Hasselhuhn, Andreas von Manteuffel, Mark Round, Carsten Schneider, Fabian Wi{\ss}brock
Heavy flavour corrections to polarised and unpolarised deep-inelastic scattering at 3-loop order
16 pages, 5 figures; contribution to the proceedings of the QCD Evolution 2016 workshop, Amsterdam
PoS(QCDEV2016)052
null
DESY 16-210, DO-TH 16/29, TTK-16-46
hep-ph
http://creativecommons.org/licenses/by-sa/4.0/
We report on progress in the calculation of 3-loop corrections to the deep-inelastic structure functions from massive quarks in the asymptotic region of large momentum transfer $Q^2$. Recently completed results allow us to obtain the $O(a_s^3)$ contributions to several heavy flavour Wilson coefficients which enter both polarised and unpolarised structure functions for lepton-nucleon scattering. In particular, we obtain the non-singlet contributions to the unpolarised structure functions $F_2(x,Q^2)$ and $x F_3(x,Q^2)$ and the polarised structure function $g_1(x,Q^2)$. From these results we also obtain the heavy flavour contributions to the Gross-Llewellyn-Smith and the Bjorken sum rules.
[ { "created": "Thu, 3 Nov 2016 17:45:33 GMT", "version": "v1" } ]
2017-01-31
[ [ "Ablinger", "Jakob", "" ], [ "Behring", "Arnd", "" ], [ "Blümlein", "Johannes", "" ], [ "De Freitas", "Abilio", "" ], [ "Hasselhuhn", "Alexander", "" ], [ "von Manteuffel", "Andreas", "" ], [ "Round", "Mark", "" ], [ "Schneider", "Carsten", "" ], [ "Wißbrock", "Fabian", "" ] ]
We report on progress in the calculation of 3-loop corrections to the deep-inelastic structure functions from massive quarks in the asymptotic region of large momentum transfer $Q^2$. Recently completed results allow us to obtain the $O(a_s^3)$ contributions to several heavy flavour Wilson coefficients which enter both polarised and unpolarised structure functions for lepton-nucleon scattering. In particular, we obtain the non-singlet contributions to the unpolarised structure functions $F_2(x,Q^2)$ and $x F_3(x,Q^2)$ and the polarised structure function $g_1(x,Q^2)$. From these results we also obtain the heavy flavour contributions to the Gross-Llewellyn-Smith and the Bjorken sum rules.
2212.13479
Ernesto A. Matute
Ernesto A. Matute
Neutrino flavor mixing with approximate $\mu$-$\tau$ symmetry within the low-scale minimal linear seesaw model
15 pages
Mod. Phys. Lett. A 37, 2250196 (2022)
10.1142/S0217732322501966
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Neutrino flavor mixing is explained within the recently proposed low-scale minimal linear seesaw model of neutrino mass generation, a variant of the standard linear seesaw led by a Dirac pair of extra sterile neutrinos which is odd under a discrete $Z_2$ symmetry and has a mass at or below the GeV scale. The tri-bimaximal mixing and its deviations are derived straightforwardly on the basis of the symmetry between $\mu$ and $\tau$ flavors, without introducing non-abelian discrete flavor symmetries in the first place.
[ { "created": "Tue, 27 Dec 2022 13:18:52 GMT", "version": "v1" } ]
2022-12-29
[ [ "Matute", "Ernesto A.", "" ] ]
Neutrino flavor mixing is explained within the recently proposed low-scale minimal linear seesaw model of neutrino mass generation, a variant of the standard linear seesaw led by a Dirac pair of extra sterile neutrinos which is odd under a discrete $Z_2$ symmetry and has a mass at or below the GeV scale. The tri-bimaximal mixing and its deviations are derived straightforwardly on the basis of the symmetry between $\mu$ and $\tau$ flavors, without introducing non-abelian discrete flavor symmetries in the first place.
hep-ph/9910338
Melles
V.S. Fadin, L.N. Lipatov, A.D. Martin, and M. Melles
Resummation of double logarithms in electroweak high energy processes
26 pages, 3 figures, Latex2e
Phys.Rev. D61 (2000) 094002
10.1103/PhysRevD.61.094002
PSI PR-99-24, DTP/99/94
hep-ph
null
At future linear $e^+e^-$ collider experiments in the TeV range, Sudakov double logarithms originating from massive boson exchange can lead to significant corrections to the cross sections of the observable processes. These effects are important for the high precision objectives of the Next Linear Collider. We use the infrared evolution equation, based on a gauge invariant dispersive method, to obtain double logarithmic asymptotics of scattering amplitudes and discuss how it can be applied, in the case of broken gauge symmetry, to the Standard Model of electroweak processes. We discuss the double logarithmic effects to both non-radiative processes and to processes accompanied by soft gauge boson emission. In all cases the Sudakov double logarithms are found to exponentiate. We also discuss double logarithmic effects of a non-Sudakov type which appear in Regge-like processes.
[ { "created": "Thu, 14 Oct 1999 14:41:57 GMT", "version": "v1" } ]
2009-10-31
[ [ "Fadin", "V. S.", "" ], [ "Lipatov", "L. N.", "" ], [ "Martin", "A. D.", "" ], [ "Melles", "M.", "" ] ]
At future linear $e^+e^-$ collider experiments in the TeV range, Sudakov double logarithms originating from massive boson exchange can lead to significant corrections to the cross sections of the observable processes. These effects are important for the high precision objectives of the Next Linear Collider. We use the infrared evolution equation, based on a gauge invariant dispersive method, to obtain double logarithmic asymptotics of scattering amplitudes and discuss how it can be applied, in the case of broken gauge symmetry, to the Standard Model of electroweak processes. We discuss the double logarithmic effects to both non-radiative processes and to processes accompanied by soft gauge boson emission. In all cases the Sudakov double logarithms are found to exponentiate. We also discuss double logarithmic effects of a non-Sudakov type which appear in Regge-like processes.
2201.04664
Lars Bathe-Peters
Lars Bathe-Peters, Steven Gardiner, Roxanne Guenette
Comparing generator predictions of transverse kinematic imbalance in neutrino-argon scattering
12 pages, 7 figures
null
null
FERMILAB-PUB-22-007-SCD
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The largest uncertainties in estimating neutrino-nucleus interaction cross sections lie in the incomplete understanding of nuclear effects. A powerful tool to study nuclear effects is Transverse Kinematic Imbalance. This paper presents the first detailed comparison of the predictions of multiple event generators for distributions associated with Transverse Kinematic Imbalance for neutrino interactions on argon. Predictions for muon neutrinos interacting with an argon target are obtained using four standard neutrino event generation tools (GENIE, NuWro, GiBUU and NEUT). Example opportunities for discrimination between nuclear models leveraging future measurements are highlighted. The predictions shown in this paper are motivated by studying muon neutrinos from the Fermilab Booster Neutrino Beam interacting at the location of the MicroBooNE liquid argon time projection chamber, but the methods directly apply to other accelerator-based liquid argon neutrino experiments such as SBND, ICARUS and DUNE.
[ { "created": "Wed, 12 Jan 2022 19:40:21 GMT", "version": "v1" } ]
2022-01-14
[ [ "Bathe-Peters", "Lars", "" ], [ "Gardiner", "Steven", "" ], [ "Guenette", "Roxanne", "" ] ]
The largest uncertainties in estimating neutrino-nucleus interaction cross sections lie in the incomplete understanding of nuclear effects. A powerful tool to study nuclear effects is Transverse Kinematic Imbalance. This paper presents the first detailed comparison of the predictions of multiple event generators for distributions associated with Transverse Kinematic Imbalance for neutrino interactions on argon. Predictions for muon neutrinos interacting with an argon target are obtained using four standard neutrino event generation tools (GENIE, NuWro, GiBUU and NEUT). Example opportunities for discrimination between nuclear models leveraging future measurements are highlighted. The predictions shown in this paper are motivated by studying muon neutrinos from the Fermilab Booster Neutrino Beam interacting at the location of the MicroBooNE liquid argon time projection chamber, but the methods directly apply to other accelerator-based liquid argon neutrino experiments such as SBND, ICARUS and DUNE.
0801.1648
Yuehong Xie
Yuehong Xie
Comment on "Resolving the sign ambiguity in $\Delta \Gamma_s$ with $B_s \to D_s K$"
null
null
null
null
hep-ph
null
This is a comment on the recent paper by Soumitra Nandi1 and Ulrich Nierste ``Resolving the sign ambiguity in $\Delta \Gamma_s$ with $B_s \to D_s K$'', arXiv:0801.0143 [hep-ph].
[ { "created": "Thu, 10 Jan 2008 18:09:26 GMT", "version": "v1" }, { "created": "Fri, 11 Jan 2008 02:00:23 GMT", "version": "v2" } ]
2008-01-11
[ [ "Xie", "Yuehong", "" ] ]
This is a comment on the recent paper by Soumitra Nandi1 and Ulrich Nierste ``Resolving the sign ambiguity in $\Delta \Gamma_s$ with $B_s \to D_s K$'', arXiv:0801.0143 [hep-ph].