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1408.6308
Hongshi Zong
Pei-lin Yin, Yuan-mei Shi, Zhu-fang Cui, Hong-tao Feng, and Hong-shi Zong
Continuum study of various susceptibilities within thermal QED$_3$
10 pages, 8 figures
Phys. Rev. D 90, 036007 (2014)
10.1103/PhysRevD.90.036007
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, the relations of four different susceptibilities (i.e., the chiral susceptibility, the fermion number susceptibility, the thermal susceptibility and the staggered spin susceptibility) are investigated both in and beyond the chiral limit. To this end, we numerically solve the finite temperature version of the truncated Dyson-Schwinger equations for fermion and boson propagator. It is found that, in the chiral limit, the four susceptibilities give the same critical temperature and signal a typical second order phase transition. But the situation changes beyond the chiral limit: the critical temperatures from the chiral and the thermal susceptibilities are different, which shows that to define a critical region instead of an exclusive point for crossover might be a more suitable choice; meanwhile, both the fermion number and the staggered spin susceptibilities have no singular behaviors any more, this may mean that they are no longer available to describe the crossover properties of the system.
[ { "created": "Wed, 27 Aug 2014 04:08:14 GMT", "version": "v1" } ]
2014-08-28
[ [ "Yin", "Pei-lin", "" ], [ "Shi", "Yuan-mei", "" ], [ "Cui", "Zhu-fang", "" ], [ "Feng", "Hong-tao", "" ], [ "Zong", "Hong-shi", "" ] ]
In this paper, the relations of four different susceptibilities (i.e., the chiral susceptibility, the fermion number susceptibility, the thermal susceptibility and the staggered spin susceptibility) are investigated both in and beyond the chiral limit. To this end, we numerically solve the finite temperature version of the truncated Dyson-Schwinger equations for fermion and boson propagator. It is found that, in the chiral limit, the four susceptibilities give the same critical temperature and signal a typical second order phase transition. But the situation changes beyond the chiral limit: the critical temperatures from the chiral and the thermal susceptibilities are different, which shows that to define a critical region instead of an exclusive point for crossover might be a more suitable choice; meanwhile, both the fermion number and the staggered spin susceptibilities have no singular behaviors any more, this may mean that they are no longer available to describe the crossover properties of the system.
hep-ph/9707263
Willy van Neerven
M. Buza, Y. Matiounine, J. Smith, W.L. van Neerven
Comparison between the various descriptions for charm electroproduction and the HERA-data
7 pages LaTex, 4 Postscript figures
Phys.Lett. B411 (1997) 211-217
10.1016/S0370-2693(97)01011-3
null
hep-ph
null
We examine the charm component F_{2,c}(x,Q^2,m^2) of the proton structure function F_2(x,Q^2) in three different schemes and compare the results with the data in the x and Q^2 region explored by the HERA experiments. Studied are (1) the three flavour number scheme (TFNS) where the production mechanisms are given by the photon-gluon fusion process and the higher order reactions with three light-flavour parton densities as input (2) the four flavour number scheme (FFNS) where F_{2,c} is expressed in four light flavour densities including one for the charm quark and (3) a variable-flavour number scheme (VFNS) which interpolates between the latter two. Both the VFNS and the TFNS give good descriptions of the experimental data. However one cannot use the FFNS for the description of the data at small Q^2.
[ { "created": "Mon, 7 Jul 1997 12:43:19 GMT", "version": "v1" } ]
2009-10-30
[ [ "Buza", "M.", "" ], [ "Matiounine", "Y.", "" ], [ "Smith", "J.", "" ], [ "van Neerven", "W. L.", "" ] ]
We examine the charm component F_{2,c}(x,Q^2,m^2) of the proton structure function F_2(x,Q^2) in three different schemes and compare the results with the data in the x and Q^2 region explored by the HERA experiments. Studied are (1) the three flavour number scheme (TFNS) where the production mechanisms are given by the photon-gluon fusion process and the higher order reactions with three light-flavour parton densities as input (2) the four flavour number scheme (FFNS) where F_{2,c} is expressed in four light flavour densities including one for the charm quark and (3) a variable-flavour number scheme (VFNS) which interpolates between the latter two. Both the VFNS and the TFNS give good descriptions of the experimental data. However one cannot use the FFNS for the description of the data at small Q^2.
1710.10459
Palash Baran Pal
Palash B. Pal, Pritibhajan Byakti
Involution symmetries and the PMNS matrix
9 pages, 1 figure, 4 tables. Talk given by PBP at the conference PHENO1 organized by IISER Mohali in April 2016
Pramana, Vol. 89 (2017) Article 63
10.1007/s12043-017-1462-4
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Lam suggested that the PMNS matrix (or at least some of its elements) can be predicted by embedding the residual symmetry of the leptonic mass terms into a bigger symmetry. We analyze the possibility that the residual symmetries consist of involution generators only and explore how Lam's idea can be implemented.
[ { "created": "Sat, 28 Oct 2017 12:51:12 GMT", "version": "v1" } ]
2017-11-08
[ [ "Pal", "Palash B.", "" ], [ "Byakti", "Pritibhajan", "" ] ]
Lam suggested that the PMNS matrix (or at least some of its elements) can be predicted by embedding the residual symmetry of the leptonic mass terms into a bigger symmetry. We analyze the possibility that the residual symmetries consist of involution generators only and explore how Lam's idea can be implemented.
1610.08409
Alexander Smirnov D.
I. V. Frolov, M. V. Martynov, A. D. Smirnov
Resonance contribution of scalar color octet to $t \bar{t}$ production at the LHC in the minimal four color quark-lepton symmetry model
12 pages, 5 figures, accepted for publication in Modern Physics Letters A
Mod. Phys. Lett. A, Vol. 31, No. 39 (2016) 1650224
10.1142/S0217732316502242
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The scalar color octet contribution to the resonance $t\bar{t}$-pair production at the LHC is calculated and analysed with account of the one loop effective two gluon vertex. It is shown that this contribution from the scalar color octet $F_2$ predicted by the minimal model with the four color quark-lepton symmetry is for $\sqrt{s}=13$ TeV of about a few percents for $750 < m_{F_2} < 1800$ GeV and can exceed 10% for $400 < m_{F_2} < 750$ GeV. It is also pointed out that the search for the scalar octet $F_2$ as the resonance in the dijet mass spectra seems to be difficult because of the smallness of its one loop effective two gluon interaction.
[ { "created": "Wed, 26 Oct 2016 16:38:06 GMT", "version": "v1" } ]
2016-12-02
[ [ "Frolov", "I. V.", "" ], [ "Martynov", "M. V.", "" ], [ "Smirnov", "A. D.", "" ] ]
The scalar color octet contribution to the resonance $t\bar{t}$-pair production at the LHC is calculated and analysed with account of the one loop effective two gluon vertex. It is shown that this contribution from the scalar color octet $F_2$ predicted by the minimal model with the four color quark-lepton symmetry is for $\sqrt{s}=13$ TeV of about a few percents for $750 < m_{F_2} < 1800$ GeV and can exceed 10% for $400 < m_{F_2} < 750$ GeV. It is also pointed out that the search for the scalar octet $F_2$ as the resonance in the dijet mass spectra seems to be difficult because of the smallness of its one loop effective two gluon interaction.
1212.3818
Aleksi Vuorinen
Yan Zhu and Aleksi Vuorinen
The shear channel spectral function in hot Yang-Mills theory
49 pages, 8 figures
null
10.1007/JHEP03(2013)002
BI-TP 2012/52, INT-PUB-12-063
hep-ph hep-lat nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We determine a next-to-leading order result for the shear channel thermal spectral function in SU(N) Yang-Mills theory, working in the limit of vanishing external three-momentum. The result is subsequently applied to the evaluation of the corresponding imaginary time correlator, and its use in the context of sum rules is discussed. Our hope is that the calculation will eventually find use in the nonperturbative determination of the shear viscosity of the theory.
[ { "created": "Sun, 16 Dec 2012 18:59:01 GMT", "version": "v1" } ]
2015-06-12
[ [ "Zhu", "Yan", "" ], [ "Vuorinen", "Aleksi", "" ] ]
We determine a next-to-leading order result for the shear channel thermal spectral function in SU(N) Yang-Mills theory, working in the limit of vanishing external three-momentum. The result is subsequently applied to the evaluation of the corresponding imaginary time correlator, and its use in the context of sum rules is discussed. Our hope is that the calculation will eventually find use in the nonperturbative determination of the shear viscosity of the theory.
hep-ph/9212298
null
K. Honjo, L. Durand, R. Gandhi, I. Sarcevic and H. Pi
High Energy Photon-Nucleon and Photon-Nucleus Cross Sections
34 pages, 6 figs. available on request from honjo@wishep. bitnet, MAD/TH/91-57, submitted to Phys. Rev. D
Phys.Rev.D48:1048-1060,1993
10.1103/PhysRevD.48.1048
null
hep-ph
null
We re\,examine the theory of hadronic photon-nucleon interactions at the quark-gluon level. The possibility of multiple parton collisions in a single photon-nucleon collision requires an eikonal treatment of the high-energy scattering process. We give a general formulation of the theory in which the $\gamma p$ cross section is expressed as a sum over properly eikonalized cross sections for the interaction of the virtual hadronic components of the photon with the proton, with each cross section weighted by the probability with which that component appears in the photon, and then develop a detailed model which includes contributions from light vector mesons and from excited virtual states described in a quark-gluon basis. The parton distribution functions which appear can be related approximately to those in the pion, while a weighted sum gives the distribution functions for the photon. We use the model to make improved QCD-based predictions for the total inelastic photon-nucleon and photon-nucleus cross sections at energies relevant for HERA experiments and cosmic ray observations. We emphasize the importance in this procedure of including a soft-scattering background such that the calculated cross sections join smoothly with low-energy data.
[ { "created": "Mon, 21 Dec 1992 23:28:31 GMT", "version": "v1" } ]
2014-11-17
[ [ "Honjo", "K.", "" ], [ "Durand", "L.", "" ], [ "Gandhi", "R.", "" ], [ "Sarcevic", "I.", "" ], [ "Pi", "H.", "" ] ]
We re\,examine the theory of hadronic photon-nucleon interactions at the quark-gluon level. The possibility of multiple parton collisions in a single photon-nucleon collision requires an eikonal treatment of the high-energy scattering process. We give a general formulation of the theory in which the $\gamma p$ cross section is expressed as a sum over properly eikonalized cross sections for the interaction of the virtual hadronic components of the photon with the proton, with each cross section weighted by the probability with which that component appears in the photon, and then develop a detailed model which includes contributions from light vector mesons and from excited virtual states described in a quark-gluon basis. The parton distribution functions which appear can be related approximately to those in the pion, while a weighted sum gives the distribution functions for the photon. We use the model to make improved QCD-based predictions for the total inelastic photon-nucleon and photon-nucleus cross sections at energies relevant for HERA experiments and cosmic ray observations. We emphasize the importance in this procedure of including a soft-scattering background such that the calculated cross sections join smoothly with low-energy data.
1406.2496
Murat Koksal
M. K\"oksal, A. Senol
Search for anomalous quartic $WWZ\gamma$ couplings at the future linear $e^{+}e^{-}$ collider
31 pages, 17 figures, 6 tables
International Journal of Modern Physics A Vol. 30 (2015) 1550107
10.1142/S0217751X15501079
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, the potentials of two different processes $e^{+}e^{-}\rightarrow W^{-} W^{+}\gamma$ and $e^{+}e^{-} \rightarrow e^{+}\gamma^{*} e^{-} \rightarrow e^{+} W^{-} Z \nu_{e}$ at the Compact Linear Collider (CLIC) are examined to probe the anomalous quartic $WWZ\gamma$ gauge couplings. For $\sqrt{s}=0.5, 1.5$ and 3 TeV energies at the CLIC, $95\%$ confidence level limits on the anomalous coupling parameters defining the dimension-six operators are found via the effective Lagrangian approach in a model independent way. The best limits on the anomalous couplings $\frac{k_{0}^{W}}{\Lambda^{2}}$, $\frac{k_{c}^{W}}{\Lambda^{2}}$, $\frac{k_{2}^{m}}{\Lambda^{2}}$ and $\frac{a_{n}}{\Lambda^{2}}$ which can be achieved with the integrated luminosity of $L_{int}=590$ fb$^{-1}$ at the CLIC with $\sqrt{s}=3$ TeV are $[-8.80;\, 8.73]\times 10^{-8}$ GeV$^{-2}$, $[-1.53; \, 1.51]\times 10^{-7}$ GeV$^{-2}$, $[-3.75; \, 3.74]\times 10^{-7}$ GeV$^{-2}$ and $[-9.13;\,9.09]\times 10^{-7}$ GeV$^{-2}$, respectively.
[ { "created": "Tue, 10 Jun 2014 10:20:38 GMT", "version": "v1" }, { "created": "Sun, 23 Nov 2014 14:03:16 GMT", "version": "v2" }, { "created": "Fri, 3 Jul 2015 07:21:59 GMT", "version": "v3" } ]
2015-07-06
[ [ "Köksal", "M.", "" ], [ "Senol", "A.", "" ] ]
In this paper, the potentials of two different processes $e^{+}e^{-}\rightarrow W^{-} W^{+}\gamma$ and $e^{+}e^{-} \rightarrow e^{+}\gamma^{*} e^{-} \rightarrow e^{+} W^{-} Z \nu_{e}$ at the Compact Linear Collider (CLIC) are examined to probe the anomalous quartic $WWZ\gamma$ gauge couplings. For $\sqrt{s}=0.5, 1.5$ and 3 TeV energies at the CLIC, $95\%$ confidence level limits on the anomalous coupling parameters defining the dimension-six operators are found via the effective Lagrangian approach in a model independent way. The best limits on the anomalous couplings $\frac{k_{0}^{W}}{\Lambda^{2}}$, $\frac{k_{c}^{W}}{\Lambda^{2}}$, $\frac{k_{2}^{m}}{\Lambda^{2}}$ and $\frac{a_{n}}{\Lambda^{2}}$ which can be achieved with the integrated luminosity of $L_{int}=590$ fb$^{-1}$ at the CLIC with $\sqrt{s}=3$ TeV are $[-8.80;\, 8.73]\times 10^{-8}$ GeV$^{-2}$, $[-1.53; \, 1.51]\times 10^{-7}$ GeV$^{-2}$, $[-3.75; \, 3.74]\times 10^{-7}$ GeV$^{-2}$ and $[-9.13;\,9.09]\times 10^{-7}$ GeV$^{-2}$, respectively.
hep-ph/0107105
Takashi Ikeda
Takashi Ikeda (U. of Tokyo)
Dressed Quark Propagator at Finite Temperature in the Schwinger-Dyson approach with the Rainbow Approximation - exact numerical solutions and their physical implication
13 pages, 8 figures, LaTeX
Prog.Theor.Phys.107:403-420,2002
10.1143/PTP.107.403
null
hep-ph
null
The Schwinger-Dyson equation for the quark in the rainbow approximation at finite temperature (T) is solved numerically without introducing any ansatz for the dressed quark propagator. The dymanical quark mass-function and the wave-function renormalization are found to have non-trivial dependence on three-momentum, Matsubara-frequency and temperature. The critical temperature of the chiral phase transition (T_c) and the T-dependence of the quark condensate are highly affected by the wave-function renormalization. We found that T_c \simeq 155 MeV which is consistent with the result of the finite temperature lattice QCD simulation. It is also found that the system is not a gas of free quarks but a highly interacting system of quarks and gluons even in the chirally symmetric phase.
[ { "created": "Tue, 10 Jul 2001 04:38:06 GMT", "version": "v1" } ]
2014-11-17
[ [ "Ikeda", "Takashi", "", "U. of Tokyo" ] ]
The Schwinger-Dyson equation for the quark in the rainbow approximation at finite temperature (T) is solved numerically without introducing any ansatz for the dressed quark propagator. The dymanical quark mass-function and the wave-function renormalization are found to have non-trivial dependence on three-momentum, Matsubara-frequency and temperature. The critical temperature of the chiral phase transition (T_c) and the T-dependence of the quark condensate are highly affected by the wave-function renormalization. We found that T_c \simeq 155 MeV which is consistent with the result of the finite temperature lattice QCD simulation. It is also found that the system is not a gas of free quarks but a highly interacting system of quarks and gluons even in the chirally symmetric phase.
hep-ph/9910417
Sheldon Stone
Sheldon Stone
Future of Heavy Flavour Physics: Experimental Perspective
Presented at "Heavy Flavours 8," Southampton, UK, July 1999, 9 pages 7 figures
null
null
null
hep-ph hep-ex
null
I discuss what measurements need to be done to search for physics beyond the Standard CKM model, rather than just what studies can be done in the near future. It is also important to accurately measure the CKM matrix elements. Current best estimates for two important elements are: |V_{cb}|=0.0381 +/- 0.0021 and |V_{ub}/V_{cb}|=0.085 +/- 0.019. Finally, future experiments are discussed.
[ { "created": "Wed, 20 Oct 1999 16:21:33 GMT", "version": "v1" }, { "created": "Thu, 21 Oct 1999 13:45:37 GMT", "version": "v2" }, { "created": "Mon, 25 Oct 1999 15:02:41 GMT", "version": "v3" }, { "created": "Sun, 7 Nov 1999 22:13:03 GMT", "version": "v4" } ]
2016-09-06
[ [ "Stone", "Sheldon", "" ] ]
I discuss what measurements need to be done to search for physics beyond the Standard CKM model, rather than just what studies can be done in the near future. It is also important to accurately measure the CKM matrix elements. Current best estimates for two important elements are: |V_{cb}|=0.0381 +/- 0.0021 and |V_{ub}/V_{cb}|=0.085 +/- 0.019. Finally, future experiments are discussed.
hep-ph/9803408
Kacper Zalewski
A. Bialas and K. Zalewski (Jagellonian University, Cracow, Poland)
HBT correlations and charge ratios in multiple production of pions
14 pages Latex, one figure available on request from the authors. In the revised version an error, affecting formulae (41)-(44) and (49), but not the general discussion and conclusions, is corrected
Eur.Phys.J.C6:349-354,1999
10.1007/s100520050346
TPJU 6(1998)
hep-ph
null
The influence of the HBT effect on the multiplicity distribution and charge ratios of independently produced pions is studied. It is shown that, for a wide class of models, there is a critical point, where the average number of pions becomes very large and the multiplicity distibution becomes very broad. In this regime unusual charge ratios ("centauros", "anticentauros") are strongly enhanced. The prospects for reaching this regime are discussed.
[ { "created": "Fri, 20 Mar 1998 17:42:19 GMT", "version": "v1" }, { "created": "Tue, 31 Mar 1998 14:10:01 GMT", "version": "v2" } ]
2011-09-13
[ [ "Bialas", "A.", "", "Jagellonian University, Cracow, Poland" ], [ "Zalewski", "K.", "", "Jagellonian University, Cracow, Poland" ] ]
The influence of the HBT effect on the multiplicity distribution and charge ratios of independently produced pions is studied. It is shown that, for a wide class of models, there is a critical point, where the average number of pions becomes very large and the multiplicity distibution becomes very broad. In this regime unusual charge ratios ("centauros", "anticentauros") are strongly enhanced. The prospects for reaching this regime are discussed.
1206.5731
James Ferrando
J. Adelman, J. Ferrando, C. D. White
NLO QCD corrections to tW' and tZ' production in forward-backward asymmetry models
62 pages, 13 figures, 36 tables. v3 Updated to correspond to Journal version and incorporate supplementary material
JHEP 1302 (2013) 091
10.1007/JHEP02(2013)091
GLAS-PPE/2012-01
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider Z' and W' models recently proposed to explain the top forward-backward asymmetry at the Tevatron. We present the next-to-leading order QCD corrections to associated production of such vector bosons together with top quarks at the Large Hadron Collider, for centre-of-mass energies of 7 and 8 TeV. The corrections are significant, modifying the total production cross-section by 30-50%. We consider the effects of the corrections on the top and vector-boson kinematics. The results are directly applicable to current experimental searches, for both the ATLAS and CMS collaborations.
[ { "created": "Mon, 25 Jun 2012 16:44:38 GMT", "version": "v1" }, { "created": "Tue, 3 Jul 2012 20:58:11 GMT", "version": "v2" }, { "created": "Mon, 18 Mar 2013 18:39:04 GMT", "version": "v3" } ]
2015-03-20
[ [ "Adelman", "J.", "" ], [ "Ferrando", "J.", "" ], [ "White", "C. D.", "" ] ]
We consider Z' and W' models recently proposed to explain the top forward-backward asymmetry at the Tevatron. We present the next-to-leading order QCD corrections to associated production of such vector bosons together with top quarks at the Large Hadron Collider, for centre-of-mass energies of 7 and 8 TeV. The corrections are significant, modifying the total production cross-section by 30-50%. We consider the effects of the corrections on the top and vector-boson kinematics. The results are directly applicable to current experimental searches, for both the ATLAS and CMS collaborations.
1106.2715
Zhen-hua Zhao
Zhen-hua Zhao
Realizing Tri-bimaximal Mixing in Minimal Seesaw Model with S4 Family Symmetry
11 pages, accepted for publication in PLB
Phys.Lett.B701:609-613,2011
10.1016/j.physletb.2011.06.050
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we realize the tri-bimaximal mixing in the lepton sector in the context of minimal seesaw in which only two right-handed neutrinos are introduced, with the discrete group $S4$ as the family symmetry. In order to constrain the form of superpotential, a $Z3$ symmetry is also introduced. In the model, the mass matrices for charged leptons and right-handed neutrinos are diagonal. The unitary matrix that diagonalizes the light Majorana neutrino mass matrix is exact tri-bimaximal at LO, and is corrected by small quantities of $\mathcal{O}(0.01)$ at NLO. The mechanism to get the particular scalar VEV alignments used is also presented. Phenomenologically, the mass spectrum is of normal hierarchy with $m_1=0$, and $\sum m_i$ and $|m_{ee}|$ are about $0.058 eV$ and $0.003 eV$ respectively.
[ { "created": "Tue, 14 Jun 2011 13:58:04 GMT", "version": "v1" }, { "created": "Mon, 20 Jun 2011 01:44:06 GMT", "version": "v2" }, { "created": "Sun, 26 Jun 2011 14:38:44 GMT", "version": "v3" }, { "created": "Tue, 5 Jul 2011 14:27:33 GMT", "version": "v4" } ]
2011-11-10
[ [ "Zhao", "Zhen-hua", "" ] ]
In this paper, we realize the tri-bimaximal mixing in the lepton sector in the context of minimal seesaw in which only two right-handed neutrinos are introduced, with the discrete group $S4$ as the family symmetry. In order to constrain the form of superpotential, a $Z3$ symmetry is also introduced. In the model, the mass matrices for charged leptons and right-handed neutrinos are diagonal. The unitary matrix that diagonalizes the light Majorana neutrino mass matrix is exact tri-bimaximal at LO, and is corrected by small quantities of $\mathcal{O}(0.01)$ at NLO. The mechanism to get the particular scalar VEV alignments used is also presented. Phenomenologically, the mass spectrum is of normal hierarchy with $m_1=0$, and $\sum m_i$ and $|m_{ee}|$ are about $0.058 eV$ and $0.003 eV$ respectively.
hep-ph/9609440
null
B. O. Kerbikov, D. S. Kuzmenko and Yu. A. Simonov (ITEP, Moscow)
Breakdown of Zero--Mode Approximation in the Instanton Vacuum
5 pages, no figures
null
null
ITEP-TH-41/96
hep-ph
null
A new approach to effective theory of quarks in the instanton vacuum is presented. Exact equations for the quark propagator and Lagrangian are derived which contain contributions of all quark modes with known coefficients. The resulting effective Lagrangian resembles that of the Nambu--Jona--Lasinio model. The commonly used zero--mode approximation is shown to be invalid in the chiral limit.
[ { "created": "Mon, 23 Sep 1996 17:37:33 GMT", "version": "v1" } ]
2007-05-23
[ [ "Kerbikov", "B. O.", "", "ITEP, Moscow" ], [ "Kuzmenko", "D. S.", "", "ITEP, Moscow" ], [ "Simonov", "Yu. A.", "", "ITEP, Moscow" ] ]
A new approach to effective theory of quarks in the instanton vacuum is presented. Exact equations for the quark propagator and Lagrangian are derived which contain contributions of all quark modes with known coefficients. The resulting effective Lagrangian resembles that of the Nambu--Jona--Lasinio model. The commonly used zero--mode approximation is shown to be invalid in the chiral limit.
hep-ph/9810472
Denis V. Ivanov
S.M. Gerasyuta
Relativistic quark model and meson Regge trajectories
latex, 14 pages
null
null
null
hep-ph
null
The D-and F-wave quark-quark amplitudes are constructed in the framework of the dispersion N/D-method. The mass values of meson multiplets with $J^{PC}=1^{--},2^{--},2^{-+},3^{--}$ and $J^{PC}=2^{++},3^{++},3^{+-},4^{++}$ are calculated. The Regge trajectories of mesonic resonances with orbital numbers L=0,1,2,3 are obtained.
[ { "created": "Sun, 25 Oct 1998 19:56:40 GMT", "version": "v1" } ]
2007-05-23
[ [ "Gerasyuta", "S. M.", "" ] ]
The D-and F-wave quark-quark amplitudes are constructed in the framework of the dispersion N/D-method. The mass values of meson multiplets with $J^{PC}=1^{--},2^{--},2^{-+},3^{--}$ and $J^{PC}=2^{++},3^{++},3^{+-},4^{++}$ are calculated. The Regge trajectories of mesonic resonances with orbital numbers L=0,1,2,3 are obtained.
hep-ph/9805226
Krzysztof Golec-Biernat
K. Golec-Biernat, J. Kwiecinski, A. D. Martin
Diffractive dijet photoproduction and the off-diagonal gluon distribution
5 pages, Latex with 3 ps figures, uses epsfig.sty and sprocl.sty. Contribution to the Proceedings of the DIS98 Workshop, Brussels, 4-8 April 1998
null
null
null
hep-ph
null
Diffractive dijet photoproduction is proposed as a probe of the off-diagonal gluon distribution and its evolution. Predictions for the transverse momentum distribution of the jets are given. Differences with DGLAP evolution are highlighted.
[ { "created": "Tue, 5 May 1998 15:23:45 GMT", "version": "v1" } ]
2007-05-23
[ [ "Golec-Biernat", "K.", "" ], [ "Kwiecinski", "J.", "" ], [ "Martin", "A. D.", "" ] ]
Diffractive dijet photoproduction is proposed as a probe of the off-diagonal gluon distribution and its evolution. Predictions for the transverse momentum distribution of the jets are given. Differences with DGLAP evolution are highlighted.
1305.3949
Shu Lin
Shu Lin, Ho-Ung Yee
Out-of-Equilibrium Chiral Magnetic Effect at Strong Coupling
1+35 pages, 8 figures. References added. Published version
null
10.1103/PhysRevD.88.025030
RBRC-1018
hep-ph hep-th nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the charge transports originating from triangle anomaly in out-of-equilibrium conditions in the framework of AdS/CFT correspondence at strong coupling, to gain useful insights on possible charge separation effects that may happen in the very early stages of heavy-ion collisions. We first construct a gravity background of a homogeneous mass shell with a finite (axial) charge density gravitationally collapsing to a charged blackhole, which serves as a dual model for out-of-equilibrium charged plasma undergoing thermalization. We find that a finite charge density in the plasma slows down the thermalization. We then study the out-of-equilibrium properties of Chiral Magnetic Effect and Chiral Magnetic Wave in this background. As the medium thermalizes, the magnitude of chiral magnetic conductivity and the response time delay grow. We find a dynamical peak in the spectral function of retarded current correlator, which we identify as an out-of-equilibrium chiral magnetic wave. The group velocity of the out-of-equilibrium chiral magnetic wave is shown to receive a dominant contribution from a non-equilibrium effect, making the wave moving much faster than in the equilibrium, which may enhance the charge transports via triangle anomaly in the early stage of heavy-ion collisions.
[ { "created": "Thu, 16 May 2013 22:45:30 GMT", "version": "v1" }, { "created": "Tue, 20 Aug 2013 03:26:34 GMT", "version": "v2" } ]
2013-08-21
[ [ "Lin", "Shu", "" ], [ "Yee", "Ho-Ung", "" ] ]
We study the charge transports originating from triangle anomaly in out-of-equilibrium conditions in the framework of AdS/CFT correspondence at strong coupling, to gain useful insights on possible charge separation effects that may happen in the very early stages of heavy-ion collisions. We first construct a gravity background of a homogeneous mass shell with a finite (axial) charge density gravitationally collapsing to a charged blackhole, which serves as a dual model for out-of-equilibrium charged plasma undergoing thermalization. We find that a finite charge density in the plasma slows down the thermalization. We then study the out-of-equilibrium properties of Chiral Magnetic Effect and Chiral Magnetic Wave in this background. As the medium thermalizes, the magnitude of chiral magnetic conductivity and the response time delay grow. We find a dynamical peak in the spectral function of retarded current correlator, which we identify as an out-of-equilibrium chiral magnetic wave. The group velocity of the out-of-equilibrium chiral magnetic wave is shown to receive a dominant contribution from a non-equilibrium effect, making the wave moving much faster than in the equilibrium, which may enhance the charge transports via triangle anomaly in the early stage of heavy-ion collisions.
hep-ph/9705273
D. P. Roy
Paul Hoyer and D.P. Roy
The Intrinsic Gluon Component of the Nucleon
Latex file (8 pages)
Phys.Lett. B410 (1997) 63-66
10.1016/S0370-2693(97)00893-9
TIFR/TH/97-15, NORDITA-97/31 P
hep-ph
null
Using an intrinsic parton model we estimate the rough shape and size of the intrinsic gluon component of the nucleon, corresponding to an energy scale $Q$ of the order $\lqcd$. It is nearly as hard in shape as the valence quark, while its size accounts for a quarter of the nucleon momentum. Both are in qualitative agreement with the input leading twist gluon distribution assumed by Gl\"uck, Reya and Vogt at this scale in order to reproduce the observed distributions at $Q^2 \gsim 1$ GeV$^2$ via perturbative QCD evolution.
[ { "created": "Fri, 9 May 1997 10:20:41 GMT", "version": "v1" } ]
2009-10-30
[ [ "Hoyer", "Paul", "" ], [ "Roy", "D. P.", "" ] ]
Using an intrinsic parton model we estimate the rough shape and size of the intrinsic gluon component of the nucleon, corresponding to an energy scale $Q$ of the order $\lqcd$. It is nearly as hard in shape as the valence quark, while its size accounts for a quarter of the nucleon momentum. Both are in qualitative agreement with the input leading twist gluon distribution assumed by Gl\"uck, Reya and Vogt at this scale in order to reproduce the observed distributions at $Q^2 \gsim 1$ GeV$^2$ via perturbative QCD evolution.
2407.21397
Gilberto Ramalho
G. Ramalho, M.T. Pe\~na, K. Tsushima and Myung-Ki Cheoun
Electromagnetic $|G_E/G_M|$ ratios of hyperons at large timelike $q^2$
8 pages, 5 figures plus supplementary material. Correct Figure 2
null
null
LFTC-24-08/91
hep-ph hep-ex hep-lat nucl-ex nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In recent years, it has become possible to measure not only the magnitude of the electric ($G_E$) and magnetic ($G_M$) form factors of spin $\frac{1}{2}$ baryons, but also to measure the relative phases of those quantities in the timelike kinematic region. Aiming to interpret present $|G_E/G_M|$ data on hyperons of the baryon octet, as well as to predict future data, we present model calculations of that ratio for large invariant 4-momentum square $q^2$ in the timelike region ($q^2>0$). Without any further parameter fitting, we extend to the timelike region a covariant quark model previously developed to describe the kinematic spacelike region ($q^2 \le 0$) of the baryon octet form factors. The model takes into account both the effects of valence quarks and the excitations of the meson cloud which dresses the baryons. We report here that our results are in good agreement with very recent data from BESIII, within the uncertainty limits of our model. We also make new predictions which may be tested in the near future, when the range of the present measurements is expanded to the 20--50 GeV$^2$ region.
[ { "created": "Wed, 31 Jul 2024 07:37:07 GMT", "version": "v1" }, { "created": "Thu, 1 Aug 2024 04:38:47 GMT", "version": "v2" } ]
2024-08-02
[ [ "Ramalho", "G.", "" ], [ "Peña", "M. T.", "" ], [ "Tsushima", "K.", "" ], [ "Cheoun", "Myung-Ki", "" ] ]
In recent years, it has become possible to measure not only the magnitude of the electric ($G_E$) and magnetic ($G_M$) form factors of spin $\frac{1}{2}$ baryons, but also to measure the relative phases of those quantities in the timelike kinematic region. Aiming to interpret present $|G_E/G_M|$ data on hyperons of the baryon octet, as well as to predict future data, we present model calculations of that ratio for large invariant 4-momentum square $q^2$ in the timelike region ($q^2>0$). Without any further parameter fitting, we extend to the timelike region a covariant quark model previously developed to describe the kinematic spacelike region ($q^2 \le 0$) of the baryon octet form factors. The model takes into account both the effects of valence quarks and the excitations of the meson cloud which dresses the baryons. We report here that our results are in good agreement with very recent data from BESIII, within the uncertainty limits of our model. We also make new predictions which may be tested in the near future, when the range of the present measurements is expanded to the 20--50 GeV$^2$ region.
hep-ph/0506293
A. V. Luchinsky
A. V. Luchinsky
Leading twist contribution to color singlet $\chi_{c0,2}\to\omega\omega$ decays
4 pages, RevTeX; minor changes, some refrences added
Phys.Atom.Nucl. 70 (2007) 53-55
10.1134/S1063778807010073
null
hep-ph
null
In this paper the leading twist contribution to $\chi_{c0,2}\to\omega\omega$ decays in the color singlet approximation is considered. It is shown, that the predictions for $\Br(\chi_0\to\omega\omega)$ is in a good agreement with the experimental data, while $\Br(\chi_{c2}\to\omega\omega)$ differs from the experiment significantly.
[ { "created": "Tue, 28 Jun 2005 15:19:22 GMT", "version": "v1" }, { "created": "Thu, 30 Jun 2005 03:47:14 GMT", "version": "v2" } ]
2009-11-11
[ [ "Luchinsky", "A. V.", "" ] ]
In this paper the leading twist contribution to $\chi_{c0,2}\to\omega\omega$ decays in the color singlet approximation is considered. It is shown, that the predictions for $\Br(\chi_0\to\omega\omega)$ is in a good agreement with the experimental data, while $\Br(\chi_{c2}\to\omega\omega)$ differs from the experiment significantly.
hep-ph/9703433
Hubert Spiesberger
T. Plehn, H. Spiesberger, M. Spira, and P.M. Zerwas
Formation and Decay of Scalar Leptoquarks/Squarks in ep collisions
10 pages, LaTex file with 3 figures, uses axodraw.sty (included)
Z.Phys. C74 (1997) 611-614
null
DESY 97-043
hep-ph
null
The cross sections for the formation of scalar resonances, leptoquarks or squarks, in electron/positron-proton collisions at HERA are presented including next-to-leading order QCD corrections. Depending mildly on the mass of the resonances, the K-factors increase the production cross sections by up to 30% if the target quarks are valence quarks. The QCD corrections to the partial decay widths of leptoquarks/squarks to leptons and quarks are small. The electron spectrum in the decays is softened nevertheless by perturbative gluon radiation at a level of 3.4 GeV for a leptoquark/squark mass of 200 GeV.
[ { "created": "Wed, 26 Mar 1997 20:17:27 GMT", "version": "v1" } ]
2007-05-23
[ [ "Plehn", "T.", "" ], [ "Spiesberger", "H.", "" ], [ "Spira", "M.", "" ], [ "Zerwas", "P. M.", "" ] ]
The cross sections for the formation of scalar resonances, leptoquarks or squarks, in electron/positron-proton collisions at HERA are presented including next-to-leading order QCD corrections. Depending mildly on the mass of the resonances, the K-factors increase the production cross sections by up to 30% if the target quarks are valence quarks. The QCD corrections to the partial decay widths of leptoquarks/squarks to leptons and quarks are small. The electron spectrum in the decays is softened nevertheless by perturbative gluon radiation at a level of 3.4 GeV for a leptoquark/squark mass of 200 GeV.
hep-ph/0007187
Chiho Nonaka
Chiho Nonaka, Eiji Honda, Shin Muroya
(3+1)-dimensional relativistic hydrodynamical expansion of hot and dense matter in ultra-relativistic nuclear collision
24 pages, 25 eps figures, LaTeX 2 epsilon
Eur.Phys.J.C17:663-673,2000
10.1007/s100520000509
TWC-00-7
hep-ph
null
A full (3+1)-dimensional calculation using the Lagrangian hydrodynamics is proposed for relativistic nuclear collisions. The calculation enables us to evaluate anisotropic flow of hadronic matter which appears in non-central and/or asymmetrical relativistic nuclear collisions. Applying hydrodynamical calculations to the deformed uranium collisions at AGS energy region, we discuss the nature of space-time structure and particle distributions in detail.
[ { "created": "Tue, 18 Jul 2000 10:06:17 GMT", "version": "v1" }, { "created": "Wed, 19 Jul 2000 02:58:11 GMT", "version": "v2" } ]
2011-09-13
[ [ "Nonaka", "Chiho", "" ], [ "Honda", "Eiji", "" ], [ "Muroya", "Shin", "" ] ]
A full (3+1)-dimensional calculation using the Lagrangian hydrodynamics is proposed for relativistic nuclear collisions. The calculation enables us to evaluate anisotropic flow of hadronic matter which appears in non-central and/or asymmetrical relativistic nuclear collisions. Applying hydrodynamical calculations to the deformed uranium collisions at AGS energy region, we discuss the nature of space-time structure and particle distributions in detail.
hep-ph/9807221
Jos Vermaseren
J. A. M. Vermaseren
Some problems in loop calculations
8 pages, LaTeX, uses appb.sty and axodraw.sty, talk given at 'Loops and Legs in gauge theories', Rheinsberg 1998
Acta Phys.Polon. B29 (1998) 2599-2609
null
NIKHEF-98-021
hep-ph
null
We discuss some of the problems that may occur in the calculation of complicated Feynman diagrams. These include the group independent evaluation of color factors, and the summation techniques that are needed for the expansion of diagrams into their Mellin moments.
[ { "created": "Thu, 2 Jul 1998 12:41:32 GMT", "version": "v1" } ]
2007-05-23
[ [ "Vermaseren", "J. A. M.", "" ] ]
We discuss some of the problems that may occur in the calculation of complicated Feynman diagrams. These include the group independent evaluation of color factors, and the summation techniques that are needed for the expansion of diagrams into their Mellin moments.
1010.4315
Marco Guzzi
Edmond L. Berger, Marco Guzzi, Hung-Liang Lai, Pavel M. Nadolsky and Fredrick I. Olness
Constraints on color-octet fermions from a global parton distribution analysis
36 pages, 14 figures. Accepted for a publication on Phys. Rev. D (2010)
Phys.Rev.D82:114023,2010
10.1103/PhysRevD.82.114023
ANL-HEP-PR-10-19, SMU-HEP-10-09
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We report a parton distribution function (PDF) analysis of a complete set of hadron scattering data, in which a color-octet fermion (such as a gluino of supersymmetry) is incorporated as an extra parton constituent along with the usual standard model constituents. The data set includes the most up-to-date results from deep-inelastic scattering and from jet production in hadron collisions. Another feature is the inclusion in the fit of data from determinations of the strong coupling alpha_s(Q) at large and small values of the hard scale Q. Our motivation is to determine the extent to which the global PDF analysis may provide constraints on the new fermion, as a function of its mass and alpha_s(M_Z), independent of assumptions such as the mechanism of gluino decays. Based on this analysis, we find that gluino masses as low as 30 to 50 GeV may be compatible with the current hadronic data. Gluino masses below 15 GeV (25 GeV) are excluded if alpha_s(M_Z) varies freely (is equal to 0.118). At the outset, stronger constraints had been anticipated from jet production cross sections, but experimental systematic uncertainties, particularly in normalization, reduce the discriminating power of these data.
[ { "created": "Wed, 20 Oct 2010 20:25:40 GMT", "version": "v1" }, { "created": "Wed, 10 Nov 2010 15:22:47 GMT", "version": "v2" } ]
2011-01-20
[ [ "Berger", "Edmond L.", "" ], [ "Guzzi", "Marco", "" ], [ "Lai", "Hung-Liang", "" ], [ "Nadolsky", "Pavel M.", "" ], [ "Olness", "Fredrick I.", "" ] ]
We report a parton distribution function (PDF) analysis of a complete set of hadron scattering data, in which a color-octet fermion (such as a gluino of supersymmetry) is incorporated as an extra parton constituent along with the usual standard model constituents. The data set includes the most up-to-date results from deep-inelastic scattering and from jet production in hadron collisions. Another feature is the inclusion in the fit of data from determinations of the strong coupling alpha_s(Q) at large and small values of the hard scale Q. Our motivation is to determine the extent to which the global PDF analysis may provide constraints on the new fermion, as a function of its mass and alpha_s(M_Z), independent of assumptions such as the mechanism of gluino decays. Based on this analysis, we find that gluino masses as low as 30 to 50 GeV may be compatible with the current hadronic data. Gluino masses below 15 GeV (25 GeV) are excluded if alpha_s(M_Z) varies freely (is equal to 0.118). At the outset, stronger constraints had been anticipated from jet production cross sections, but experimental systematic uncertainties, particularly in normalization, reduce the discriminating power of these data.
1109.6548
M Vepsalainen
Y. Schroder, M. Vepsalainen, A. Vuorinen, Y. Zhu
The ultraviolet limit and sum rule for the shear correlator in hot Yang-Mills theory
16 pages, 2 figures. v2: small clarifications, one reference added, published version
null
10.1007/JHEP12(2011)035
BI-TP 2011/39
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We determine a next-to-leading order result for the correlator of the shear stress operator in high-temperature Yang-Mills theory. The computation is performed via an ultraviolet expansion, valid in the limit of small distances or large momenta, and the result is used for writing operator product expansions for the Euclidean momentum and coordinate space correlators as well as for the Minkowskian spectral density. In addition, our results enable us to confirm and refine a shear sum rule originally derived by Romatschke, Son and Meyer.
[ { "created": "Thu, 29 Sep 2011 14:54:08 GMT", "version": "v1" }, { "created": "Fri, 25 Nov 2011 14:26:35 GMT", "version": "v2" } ]
2015-05-30
[ [ "Schroder", "Y.", "" ], [ "Vepsalainen", "M.", "" ], [ "Vuorinen", "A.", "" ], [ "Zhu", "Y.", "" ] ]
We determine a next-to-leading order result for the correlator of the shear stress operator in high-temperature Yang-Mills theory. The computation is performed via an ultraviolet expansion, valid in the limit of small distances or large momenta, and the result is used for writing operator product expansions for the Euclidean momentum and coordinate space correlators as well as for the Minkowskian spectral density. In addition, our results enable us to confirm and refine a shear sum rule originally derived by Romatschke, Son and Meyer.
hep-ph/9803287
Regina Nebauer
Regina Nebauer and J\"org Aichelin
Dynamical fragment production in central collisions Xe(50 A.MeV)+Sn
To appear in the Proceedings of the 36th International Winter Meeting on Nuclear Physics, Bormio, Italy, Jan. 26-31 1998
null
null
null
hep-ph
null
For central collisions Xe(50 A.MeV)+Sn we compared experimental data from the INDRA detector with QMD simulations. Theory as well as experiment show a clear binary character of the fragment emission even for very central collisions. From the time evolution of the reaction (QMD simulation) we could built up a scenario for the dynamical emission of fragments
[ { "created": "Mon, 9 Mar 1998 15:51:17 GMT", "version": "v1" } ]
2016-09-06
[ [ "Nebauer", "Regina", "" ], [ "Aichelin", "Jörg", "" ] ]
For central collisions Xe(50 A.MeV)+Sn we compared experimental data from the INDRA detector with QMD simulations. Theory as well as experiment show a clear binary character of the fragment emission even for very central collisions. From the time evolution of the reaction (QMD simulation) we could built up a scenario for the dynamical emission of fragments
1610.03250
Yao-Bei Liu
Yao-Bei Liu, Zhen-Jun Xiao
Searches for the FCNC couplings from top-Higgs associated production signal with $h\to \gamma\gamma$ at the LHC
null
Phys. Lett. B 763 (2016) 458-464
10.1016/j.physletb.2016.11.004
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we study the observability of the top-Higgs flavor changing neutral current (FCNC) $tqh$ coupling through the process $pp\to qg\to t(\to \ell^{+}b\nu)h(\to \gamma\gamma)$ at the Large Hadron Collider~(LHC), where $\ell=e, \mu$. Our numerical results show that, in some parameter regions, the LHC may observe the above signals at the $5\sigma$ level. Otherwise, the branching ratios $Br(t\to uh)$ and $Br(t\to ch)$ can be respectively probed to $0.036\%$ and $0.13\%$ at $3\sigma$ level at 14 TeV LHC with the high integrated luminosity of 3000 fb$^{-1}$. On the other hand, studying the charge ratio for the lepton in top quark decay can be not only used to discriminate between signal and backgrounds, but also used to discriminate between $tuh$ and $tch$ couplings, for which anomalous single top production comes from the up initiated channel and charm initiated channel.
[ { "created": "Tue, 11 Oct 2016 09:32:36 GMT", "version": "v1" }, { "created": "Thu, 3 Nov 2016 10:16:03 GMT", "version": "v2" }, { "created": "Thu, 17 Nov 2016 01:14:49 GMT", "version": "v3" } ]
2016-11-18
[ [ "Liu", "Yao-Bei", "" ], [ "Xiao", "Zhen-Jun", "" ] ]
In this paper, we study the observability of the top-Higgs flavor changing neutral current (FCNC) $tqh$ coupling through the process $pp\to qg\to t(\to \ell^{+}b\nu)h(\to \gamma\gamma)$ at the Large Hadron Collider~(LHC), where $\ell=e, \mu$. Our numerical results show that, in some parameter regions, the LHC may observe the above signals at the $5\sigma$ level. Otherwise, the branching ratios $Br(t\to uh)$ and $Br(t\to ch)$ can be respectively probed to $0.036\%$ and $0.13\%$ at $3\sigma$ level at 14 TeV LHC with the high integrated luminosity of 3000 fb$^{-1}$. On the other hand, studying the charge ratio for the lepton in top quark decay can be not only used to discriminate between signal and backgrounds, but also used to discriminate between $tuh$ and $tch$ couplings, for which anomalous single top production comes from the up initiated channel and charm initiated channel.
hep-ph/0411228
Hong Li
Hong Li, Zigao Dai and Xinmin Zhang
Testing Mass Varying Neutrino With Short Gamma Ray Burst
4 pages, 4 figures Revtex4
Phys.Rev.D71:113003,2005
10.1103/PhysRevD.71.113003
null
hep-ph astro-ph gr-qc hep-th
null
In this paper we study the possibility of probing for the absolute neutrino mass and its variation with short Gamma Ray Burst (GRB). We have calculated the flight time difference between a massive neutrino and a photon in two different approaches to mass varying neutrinos. Firstly we parametrize the neutrino mass as a function of redshift in a model independent way, then we consider two specific models where the neutrino mass varies during the evolution of the Quintessence fields. Our calculations show in general the value of the time delay is changed substantially relative to a constant neutrino mass. Furthermore our numerical results show that the flight time delay in these models is expected to be larger than the duration time of the short GRB, which opens a possibility of testing the scenario of mass varying neutrino with the short GRB.
[ { "created": "Wed, 17 Nov 2004 11:08:31 GMT", "version": "v1" } ]
2014-11-18
[ [ "Li", "Hong", "" ], [ "Dai", "Zigao", "" ], [ "Zhang", "Xinmin", "" ] ]
In this paper we study the possibility of probing for the absolute neutrino mass and its variation with short Gamma Ray Burst (GRB). We have calculated the flight time difference between a massive neutrino and a photon in two different approaches to mass varying neutrinos. Firstly we parametrize the neutrino mass as a function of redshift in a model independent way, then we consider two specific models where the neutrino mass varies during the evolution of the Quintessence fields. Our calculations show in general the value of the time delay is changed substantially relative to a constant neutrino mass. Furthermore our numerical results show that the flight time delay in these models is expected to be larger than the duration time of the short GRB, which opens a possibility of testing the scenario of mass varying neutrino with the short GRB.
0807.0600
Jean-Rene Cudell
J.R. Cudell, A. Dechambre, O. F. Hern\'andez and I. P. Ivanov
Central exclusive production of dijets at hadronic colliders
37 pages, 18 figures. Two new appendices, and a discussion of the upper scale of the Sudakov form factor are introduced. The text about the calculation of the uncertainties has been rewritten
Eur.Phys.J.C61:369-390,2009
10.1140/epjc/s10052-009-0994-2
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In view of the recent diffractive dijet data from CDF run II, we critically re-evaluate the standard approach to the calculation of central production of dijets in quasi-elastic hadronic collisions. We find that the process is dominated by the non-perturbative region, and that even perturbative ingredients, such as the Sudakov form factor, are not under theoretical control. Comparison with data allows us to fix some of the uncertainties. Although we focus on dijets, our arguments apply to other high-mass central systems, such as the Higgs boson.
[ { "created": "Thu, 3 Jul 2008 19:45:30 GMT", "version": "v1" }, { "created": "Mon, 10 Nov 2008 13:34:29 GMT", "version": "v2" } ]
2009-07-22
[ [ "Cudell", "J. R.", "" ], [ "Dechambre", "A.", "" ], [ "Hernández", "O. F.", "" ], [ "Ivanov", "I. P.", "" ] ]
In view of the recent diffractive dijet data from CDF run II, we critically re-evaluate the standard approach to the calculation of central production of dijets in quasi-elastic hadronic collisions. We find that the process is dominated by the non-perturbative region, and that even perturbative ingredients, such as the Sudakov form factor, are not under theoretical control. Comparison with data allows us to fix some of the uncertainties. Although we focus on dijets, our arguments apply to other high-mass central systems, such as the Higgs boson.
hep-ph/0111105
Tao Huang
Tao Huang, Zuo-Hong Li and Xiang-Yao Wu
The heavy-to-light transitions in the light-cone QCD sum rules
Talk given at Internatinal Comference on Flavor Physics (ICFP 2001), Zhang-Jia-Jie city, Hunan, China, 31 May - 6 Jun, 2001
null
10.1142/9789812777379_0037
null
hep-ph
null
We have analyzed the $B\to \pi $ and $B_{s}\to K$ semileptonic form factors and $B\to V\gamma (V=K^*,\rho,\omega)$ processes in the light-cone QCD sum rules. In order to enhance the predictivity and reliability of numerical results the chiral-current correlator is employed and the twist-3 light-cone wavefunction can be effectively eliminated from the sum rules.
[ { "created": "Fri, 9 Nov 2001 07:33:54 GMT", "version": "v1" } ]
2017-08-23
[ [ "Huang", "Tao", "" ], [ "Li", "Zuo-Hong", "" ], [ "Wu", "Xiang-Yao", "" ] ]
We have analyzed the $B\to \pi $ and $B_{s}\to K$ semileptonic form factors and $B\to V\gamma (V=K^*,\rho,\omega)$ processes in the light-cone QCD sum rules. In order to enhance the predictivity and reliability of numerical results the chiral-current correlator is employed and the twist-3 light-cone wavefunction can be effectively eliminated from the sum rules.
1212.6829
Alexander Bednyakov
A. V. Bednyakov, A. F. Pikelner, V. N. Velizhanin
Yukawa coupling beta-functions in the Standard Model at three loops
7 pages, 1 figure, discussion about gamma5 extended, numerical estimates changed according to new ancillary files with correct results
null
10.1016/j.physletb.2013.04.038
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present the results for three-loop beta-functions for Yukawa couplings of heavy Standard Model fermions calculated within the unbroken phase of the model. The calculation is carried out with the help of the MINCER program in a general linear gauge, and the final result is independent of the gauge-fixing parameters. In order to calculate three-point functions, we made use of infrared rearrangement (IRR) trick. Due to the chiral structure of the SM a careful treatment of loops with fermions is required to perform the calculation. It turns out that gauge anomaly cancellation in the SM allows us to obtain the result by means of the semi-naive treatment of gamma5.
[ { "created": "Mon, 31 Dec 2012 07:00:30 GMT", "version": "v1" }, { "created": "Thu, 17 Jan 2013 06:21:58 GMT", "version": "v2" }, { "created": "Thu, 21 Mar 2013 07:52:47 GMT", "version": "v3" } ]
2015-06-12
[ [ "Bednyakov", "A. V.", "" ], [ "Pikelner", "A. F.", "" ], [ "Velizhanin", "V. N.", "" ] ]
We present the results for three-loop beta-functions for Yukawa couplings of heavy Standard Model fermions calculated within the unbroken phase of the model. The calculation is carried out with the help of the MINCER program in a general linear gauge, and the final result is independent of the gauge-fixing parameters. In order to calculate three-point functions, we made use of infrared rearrangement (IRR) trick. Due to the chiral structure of the SM a careful treatment of loops with fermions is required to perform the calculation. It turns out that gauge anomaly cancellation in the SM allows us to obtain the result by means of the semi-naive treatment of gamma5.
0811.4622
Frank Siegert
T. Gleisberg, S. Hoeche, F. Krauss, M. Schoenherr, S. Schumann, F. Siegert, J. Winter
Event generation with SHERPA 1.1
47 pages, 21 figures
JHEP 0902:007,2009
10.1088/1126-6708/2009/02/007
SLAC-PUB-13420, ZU-TH 17/08, DCPT/08/138, IPPP/08/69, Edinburgh 2008/30, FERMILAB-PUB-08-477-T, MCNET/08/14
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper the current release of the Monte Carlo event generator Sherpa, version 1.1, is presented. Sherpa is a general-purpose tool for the simulation of particle collisions at high-energy colliders. It contains a very flexible tree-level matrix-element generator for the calculation of hard scattering processes within the Standard Model and various new physics models. The emission of additional QCD partons off the initial and final states is described through a parton-shower model. To consistently combine multi-parton matrix elements with the QCD parton cascades the approach of Catani, Krauss, Kuhn and Webber is employed. A simple model of multiple interactions is used to account for underlying events in hadron--hadron collisions. The fragmentation of partons into primary hadrons is described using a phenomenological cluster-hadronisation model. A comprehensive library for simulating tau-lepton and hadron decays is provided. Where available form-factor models and matrix elements are used, allowing for the inclusion of spin correlations; effects of virtual and real QED corrections are included using the approach of Yennie, Frautschi and Suura.
[ { "created": "Thu, 27 Nov 2008 22:32:59 GMT", "version": "v1" } ]
2009-02-12
[ [ "Gleisberg", "T.", "" ], [ "Hoeche", "S.", "" ], [ "Krauss", "F.", "" ], [ "Schoenherr", "M.", "" ], [ "Schumann", "S.", "" ], [ "Siegert", "F.", "" ], [ "Winter", "J.", "" ] ]
In this paper the current release of the Monte Carlo event generator Sherpa, version 1.1, is presented. Sherpa is a general-purpose tool for the simulation of particle collisions at high-energy colliders. It contains a very flexible tree-level matrix-element generator for the calculation of hard scattering processes within the Standard Model and various new physics models. The emission of additional QCD partons off the initial and final states is described through a parton-shower model. To consistently combine multi-parton matrix elements with the QCD parton cascades the approach of Catani, Krauss, Kuhn and Webber is employed. A simple model of multiple interactions is used to account for underlying events in hadron--hadron collisions. The fragmentation of partons into primary hadrons is described using a phenomenological cluster-hadronisation model. A comprehensive library for simulating tau-lepton and hadron decays is provided. Where available form-factor models and matrix elements are used, allowing for the inclusion of spin correlations; effects of virtual and real QED corrections are included using the approach of Yennie, Frautschi and Suura.
0707.2046
Javier Virto
Javier Virto (Barcelona, IFAE)
Evading 1/m_b-suppressed IR divergencies in QCDF: Bs-->KK Decays and B_{d,s} mixing
5 pages. Talk given at the International Workshop on Quantum Chromodynamics: QCD@Work 2007, Martina Franca, Italy, June 2007
AIP Conf.Proc.964:90-94,2007
10.1063/1.2823886
UAB-FT-641
hep-ph
null
We analyze the deviations of the mixing induced CP asymmetry in B-->phi Ks from sin(2beta), as well as the deviations of the asymmetries in Bs-->K*K*, Bs-->phi K* and Bs-->phi phi from sin(2beta_s), that arise in SM due to penguin pollution. We use a theoretical input which is short-distance dominated in QCD-factorization and thus free of IR-divergencies. We also provide alternative ways to extract angles of the unitarity triangle from penguin-mediated decays, and give predictions for Bs-->K*K* observables.
[ { "created": "Fri, 13 Jul 2007 16:01:16 GMT", "version": "v1" } ]
2011-03-23
[ [ "Virto", "Javier", "", "Barcelona, IFAE" ] ]
We analyze the deviations of the mixing induced CP asymmetry in B-->phi Ks from sin(2beta), as well as the deviations of the asymmetries in Bs-->K*K*, Bs-->phi K* and Bs-->phi phi from sin(2beta_s), that arise in SM due to penguin pollution. We use a theoretical input which is short-distance dominated in QCD-factorization and thus free of IR-divergencies. We also provide alternative ways to extract angles of the unitarity triangle from penguin-mediated decays, and give predictions for Bs-->K*K* observables.
2212.14570
HyungJoo Kim
HyungJoo Kim, Sungtae Cho, Su Houng Lee
Spin-1 quarkonia in a rotating frame and their spin contents
5 pages, 2 figures
null
10.1016/j.physletb.2023.137986
null
hep-ph hep-ex nucl-ex nucl-th
http://creativecommons.org/licenses/by-sa/4.0/
We propose a new way of studying the spin content of a hadron by looking at its response in a rotating frame. By collecting all responses of quarks and gluons in a rotating frame, we describe the spin-rotation coupling of spin-1 quarkonia and thereby reveal their spin contents in a relativistic formalism. We demonstrate that both the perturbative and non-perturbative contributions in the operator product expansion follow a universal formula that identifies the spin-rotation coupling with unit strength. This allows us to recognize the total spin-1 of the vector and axial vector quarkonia in terms of the total angular momentum of quarks and gluons. Specifically, we find the spin contents of $J/\psi$, $\chi_{c1}$, $\Upsilon(1S)$, and $\chi_{b1}$ are slightly different from the naive quark model picture. For example, the $J/\psi$ is traditionally considered as an S-wave particle, but we find quarks do not carry all of the total spin.
[ { "created": "Fri, 30 Dec 2022 07:03:02 GMT", "version": "v1" }, { "created": "Mon, 26 Jun 2023 03:03:31 GMT", "version": "v2" } ]
2023-06-28
[ [ "Kim", "HyungJoo", "" ], [ "Cho", "Sungtae", "" ], [ "Lee", "Su Houng", "" ] ]
We propose a new way of studying the spin content of a hadron by looking at its response in a rotating frame. By collecting all responses of quarks and gluons in a rotating frame, we describe the spin-rotation coupling of spin-1 quarkonia and thereby reveal their spin contents in a relativistic formalism. We demonstrate that both the perturbative and non-perturbative contributions in the operator product expansion follow a universal formula that identifies the spin-rotation coupling with unit strength. This allows us to recognize the total spin-1 of the vector and axial vector quarkonia in terms of the total angular momentum of quarks and gluons. Specifically, we find the spin contents of $J/\psi$, $\chi_{c1}$, $\Upsilon(1S)$, and $\chi_{b1}$ are slightly different from the naive quark model picture. For example, the $J/\psi$ is traditionally considered as an S-wave particle, but we find quarks do not carry all of the total spin.
hep-ph/9812222
Francesco Pietropaolo
P. Picchi, F. Pietropaolo
Physics Projects for a Future CERN-LNGS Neutrino Programme
11 pages, 4 figures, to appear in the Proceedings of the XVIII International Conference on Neutrino Physics and Astrphysics, Takayama, Japan, 1998
Nucl.Phys.Proc.Suppl. 77 (1999) 187-197
10.1016/S0920-5632(99)00417-X
null
hep-ph
null
We present an overview of the future projects concerning the neutrino oscillation physics in Europe. Recently a joint CERN-LNGS scientific committee has reviewed several proposals both for the study of atmospheric neutrinos and for long (LBL) and short baseline (SBL) neutrino oscillation experiments. The committee has indicated the priority that the European high energy physics community should follows in the field of neutrino physics, namely a new massive, atmospheric neutrino detector and a nu_tau appearance campaign exploiting the new CERN-LNGS Neutrino Facility (NGS), freshly approved by CERN and INFN. The sensitivity and the discovery potential of the whole experimental program in the Super-Kamiokande allowed region are discussed.
[ { "created": "Wed, 2 Dec 1998 09:31:36 GMT", "version": "v1" }, { "created": "Thu, 3 Dec 1998 14:28:17 GMT", "version": "v2" } ]
2009-10-31
[ [ "Picchi", "P.", "" ], [ "Pietropaolo", "F.", "" ] ]
We present an overview of the future projects concerning the neutrino oscillation physics in Europe. Recently a joint CERN-LNGS scientific committee has reviewed several proposals both for the study of atmospheric neutrinos and for long (LBL) and short baseline (SBL) neutrino oscillation experiments. The committee has indicated the priority that the European high energy physics community should follows in the field of neutrino physics, namely a new massive, atmospheric neutrino detector and a nu_tau appearance campaign exploiting the new CERN-LNGS Neutrino Facility (NGS), freshly approved by CERN and INFN. The sensitivity and the discovery potential of the whole experimental program in the Super-Kamiokande allowed region are discussed.
2312.13724
Craig Roberts
Chen Chen, Christian S. Fischer and Craig D. Roberts
Nucleon to $\Delta$ axial and pseudoscalar transition form factors
8 pages, 6 figures, 3 tables
null
null
NJU-INP 082/23, USTC-ICTS/PCFT-23-40
hep-ph hep-ex hep-lat nucl-ex nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A symmetry-preserving continuum approach to the calculation of baryon properties in relativistic quantum field theory is used to predict all form factors associated with nucleon-to-$\Delta$ axial and pseudoscalar transition currents, thereby unifying them with many additional properties of these and other baryons. The new parameter-free predictions can serve as credible benchmarks for use in analysing existing and anticipated data from worldwide efforts focused on elucidation of $\nu$ properties.
[ { "created": "Thu, 21 Dec 2023 10:43:01 GMT", "version": "v1" } ]
2023-12-22
[ [ "Chen", "Chen", "" ], [ "Fischer", "Christian S.", "" ], [ "Roberts", "Craig D.", "" ] ]
A symmetry-preserving continuum approach to the calculation of baryon properties in relativistic quantum field theory is used to predict all form factors associated with nucleon-to-$\Delta$ axial and pseudoscalar transition currents, thereby unifying them with many additional properties of these and other baryons. The new parameter-free predictions can serve as credible benchmarks for use in analysing existing and anticipated data from worldwide efforts focused on elucidation of $\nu$ properties.
1310.3374
Jeonghyeon Song
Sanghyeon Chang, Sin Kyu Kang, Jong-Phil Lee, Kang Young Lee, Seong Chan Park, and Jeonghyeon Song
Two Higgs doublet models for the LHC Higgs boson data at $\sqrt{s}=$ 7 and 8 TeV
To appear in JHEP
null
10.1007/JHEP09(2014)101
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Updated LHC data on the new 126 GeV boson during the 7 and 8 TeV runnings strengthen the standard model Higgs boson interpretation further. Through the global $\chi^2$ analysis, we investigate whether the new particle could be one of the scalar particles in two Higgs doublet models. Four types (Type I, II, X and Y) are comprehensively studied. Taking the recent analysis on the spin-parity of the new boson, we consider two scenarios: the new boson is either the light CP-even one ($h^0$) or the heavy CP-even one ($H^0$). It is found that both scenarios are consistent with the new data, not only in the parameter regions near the decoupling limit but also in other regions far from the decoupling limit. In addition, the current data are compatible with the possibility that the light Higgs boson $h^0$ is hidden in the mass window of 90-100 GeV. The diphoton or $\tau\tau$ channel can provide a probe of this possibility by the enhanced signal rates.
[ { "created": "Sat, 12 Oct 2013 13:45:10 GMT", "version": "v1" }, { "created": "Wed, 23 Oct 2013 02:11:57 GMT", "version": "v2" }, { "created": "Tue, 12 Aug 2014 06:44:58 GMT", "version": "v3" } ]
2015-06-17
[ [ "Chang", "Sanghyeon", "" ], [ "Kang", "Sin Kyu", "" ], [ "Lee", "Jong-Phil", "" ], [ "Lee", "Kang Young", "" ], [ "Park", "Seong Chan", "" ], [ "Song", "Jeonghyeon", "" ] ]
Updated LHC data on the new 126 GeV boson during the 7 and 8 TeV runnings strengthen the standard model Higgs boson interpretation further. Through the global $\chi^2$ analysis, we investigate whether the new particle could be one of the scalar particles in two Higgs doublet models. Four types (Type I, II, X and Y) are comprehensively studied. Taking the recent analysis on the spin-parity of the new boson, we consider two scenarios: the new boson is either the light CP-even one ($h^0$) or the heavy CP-even one ($H^0$). It is found that both scenarios are consistent with the new data, not only in the parameter regions near the decoupling limit but also in other regions far from the decoupling limit. In addition, the current data are compatible with the possibility that the light Higgs boson $h^0$ is hidden in the mass window of 90-100 GeV. The diphoton or $\tau\tau$ channel can provide a probe of this possibility by the enhanced signal rates.
hep-ph/0507155
Phung Dong Van
Phung Van Dong and Hoang Ngoc Long
Electric Charge Quantization in SU(3)_C X SU(3)_L X U(1)_X Models
14 pages
Int.J.Mod.Phys.A21:6677-6692,2006
10.1142/S0217751X06035191
null
hep-ph
null
Basing on the general photon eigenstate and the anomaly cancelation, we have naturally explained the electric charge quantization in two models based on the SU(3)_C X SU(3)_L X U(1)_X gauge group, namely in the minimal model and in the model with right-handed neutrinos. In addition, we have shown that the electric charges of the proton and of the electron are opposite; and the same happens with the neutron and the neutrino. We argue that the electric charge quantization is not dependent on the classical constraints on generating mass to the fermions, but it is related closely with the generation number problem. In fact, both problems are properly solved as the direct consequences of the fermion content under the anomaly free conditions.
[ { "created": "Wed, 13 Jul 2005 14:14:55 GMT", "version": "v1" } ]
2008-11-26
[ [ "Van Dong", "Phung", "" ], [ "Long", "Hoang Ngoc", "" ] ]
Basing on the general photon eigenstate and the anomaly cancelation, we have naturally explained the electric charge quantization in two models based on the SU(3)_C X SU(3)_L X U(1)_X gauge group, namely in the minimal model and in the model with right-handed neutrinos. In addition, we have shown that the electric charges of the proton and of the electron are opposite; and the same happens with the neutron and the neutrino. We argue that the electric charge quantization is not dependent on the classical constraints on generating mass to the fermions, but it is related closely with the generation number problem. In fact, both problems are properly solved as the direct consequences of the fermion content under the anomaly free conditions.
1812.10940
Toshifumi Yamada
Naoyuki Haba, Yukihiro Mimura and Toshifumi Yamada
On $\theta_{23}$ Octant Measurement in $3+1$ Neutrino Oscillations in T2HKK
27 pages, 7 figures. Study on the impact of non-zero $\theta_{34}$ mixing is added. Version accepted for publication in Physical Review D
Phys. Rev. D 101, 075034 (2020)
10.1103/PhysRevD.101.075034
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It has been pointed out that the mixing of an eV-scale sterile neutrino with active flavors can lead to loss of sensitivity to the $\theta_{23}$ octant (sign of $\sin^2\theta_{23}-1/2$) in long baseline experiments, because the main oscillation probability $P_0=4\sin^2\theta_{23}\sin^2\theta_{13}\sin^2\Delta_{31}$ can be degenerate with the sum of the interferences with the solar oscillation amplitude and an active-sterile oscillation amplitude in both neutrino and antineutrino oscillations, depending on CP phases. In this paper, we show that the above degeneracy is resolved by measuring the same beam at different baseline lengths. We demonstrate that Tokai-to-Hyper-Kamiokande-to-Korea (T2HKK) experiment (one 187~kton fiducial volume water Cerenkov detector is placed at Kamioka, $L=295$~km, and another detector is put in Korea, $L\sim1000$~km) exhibits a better sensitivity to the $\theta_{23}$ octant in those parameter regions where the experiment with two detectors at Kamioka is insensitive to it. Therefore, if a hint of sterile-active mixings is discovered in short baseline experiments, T2HKK is a better option than the plan of placing two detectors at Kamioka. We also consider an alternative case where one detector is placed at Kamioka and a different detector is at Oki Islands, $L=653$~km, and show that this configuration also leads to a better sensitivity to the $\theta_{23}$ octant.
[ { "created": "Fri, 28 Dec 2018 09:58:31 GMT", "version": "v1" }, { "created": "Mon, 30 Mar 2020 10:26:21 GMT", "version": "v2" } ]
2020-04-22
[ [ "Haba", "Naoyuki", "" ], [ "Mimura", "Yukihiro", "" ], [ "Yamada", "Toshifumi", "" ] ]
It has been pointed out that the mixing of an eV-scale sterile neutrino with active flavors can lead to loss of sensitivity to the $\theta_{23}$ octant (sign of $\sin^2\theta_{23}-1/2$) in long baseline experiments, because the main oscillation probability $P_0=4\sin^2\theta_{23}\sin^2\theta_{13}\sin^2\Delta_{31}$ can be degenerate with the sum of the interferences with the solar oscillation amplitude and an active-sterile oscillation amplitude in both neutrino and antineutrino oscillations, depending on CP phases. In this paper, we show that the above degeneracy is resolved by measuring the same beam at different baseline lengths. We demonstrate that Tokai-to-Hyper-Kamiokande-to-Korea (T2HKK) experiment (one 187~kton fiducial volume water Cerenkov detector is placed at Kamioka, $L=295$~km, and another detector is put in Korea, $L\sim1000$~km) exhibits a better sensitivity to the $\theta_{23}$ octant in those parameter regions where the experiment with two detectors at Kamioka is insensitive to it. Therefore, if a hint of sterile-active mixings is discovered in short baseline experiments, T2HKK is a better option than the plan of placing two detectors at Kamioka. We also consider an alternative case where one detector is placed at Kamioka and a different detector is at Oki Islands, $L=653$~km, and show that this configuration also leads to a better sensitivity to the $\theta_{23}$ octant.
1108.0346
Valery Lyubovitskij
Thomas Gutsche, Valery E. Lyubovitskij, Ivan Schmidt, Alfredo Vega
Dilaton in a soft-wall holographic approach to mesons and baryons
21 pages, accepted for publication in Phys. Rev. D
Phys.Rev.D85:076003,2012
10.1103/PhysRevD.85.076003
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We discuss a holographic soft-wall model developed for the description of mesons and baryons with adjustable quantum numbers n, J, L, S. This approach is based on an action which describes hadrons with broken conformal invariance and which incorporates confinement through the presence of a background dilaton field. We show that in the case of the bound-state problem (hadronic mass spectrum) two versions of the model with a positive and negative dilaton profile are equivalent to each other by a special transformation of the bulk field. We also comment on recent works which discuss the dilaton sign in the context of soft-wall approaches.
[ { "created": "Mon, 1 Aug 2011 16:02:03 GMT", "version": "v1" }, { "created": "Fri, 27 Jan 2012 08:52:01 GMT", "version": "v2" } ]
2012-04-05
[ [ "Gutsche", "Thomas", "" ], [ "Lyubovitskij", "Valery E.", "" ], [ "Schmidt", "Ivan", "" ], [ "Vega", "Alfredo", "" ] ]
We discuss a holographic soft-wall model developed for the description of mesons and baryons with adjustable quantum numbers n, J, L, S. This approach is based on an action which describes hadrons with broken conformal invariance and which incorporates confinement through the presence of a background dilaton field. We show that in the case of the bound-state problem (hadronic mass spectrum) two versions of the model with a positive and negative dilaton profile are equivalent to each other by a special transformation of the bulk field. We also comment on recent works which discuss the dilaton sign in the context of soft-wall approaches.
2211.16489
Siwei Hu
Siwei Hu, Yu Jia, Zhewen Mo, Xiaonu Xiong, Mingliang Zhu
Parton distribution of intrinsic charm in two dimensional QCD
14 pages, 6 figures, 1 table
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a detailed investigation on the intrinsic charm content in a light meson within the 't Hooft model, namely, the two-dimensional QCD in large $N_c$ limit. The intrinsic charm parton distribution function (PDF) of a light meson, which first arises at order $N_c^{-1}$, is explicitly expressed in terms of the 't Hooft wave functions of the light meson and an infinite towers of excited charmed mesons. We also derive the functional forms from the two-dimensional counterparts of the meson cloud model (MCM) and Brodsky-Hoyer-Peterson-Sakai (BHPS) model. We then make a quantitative comparison between our rigorous results and model predictions. We also study how the profile of the intrinsic charm PDF varies with charm quark mass. The average momentum fraction carried by the charm quark inside a light meson is found to decrease faster than $m_c^{-4}$ with increasing charm quark mass.
[ { "created": "Tue, 29 Nov 2022 18:56:30 GMT", "version": "v1" }, { "created": "Thu, 9 Feb 2023 15:38:11 GMT", "version": "v2" } ]
2023-02-10
[ [ "Hu", "Siwei", "" ], [ "Jia", "Yu", "" ], [ "Mo", "Zhewen", "" ], [ "Xiong", "Xiaonu", "" ], [ "Zhu", "Mingliang", "" ] ]
We present a detailed investigation on the intrinsic charm content in a light meson within the 't Hooft model, namely, the two-dimensional QCD in large $N_c$ limit. The intrinsic charm parton distribution function (PDF) of a light meson, which first arises at order $N_c^{-1}$, is explicitly expressed in terms of the 't Hooft wave functions of the light meson and an infinite towers of excited charmed mesons. We also derive the functional forms from the two-dimensional counterparts of the meson cloud model (MCM) and Brodsky-Hoyer-Peterson-Sakai (BHPS) model. We then make a quantitative comparison between our rigorous results and model predictions. We also study how the profile of the intrinsic charm PDF varies with charm quark mass. The average momentum fraction carried by the charm quark inside a light meson is found to decrease faster than $m_c^{-4}$ with increasing charm quark mass.
hep-ph/0011297
Mohan
Mohan Narayan and S. Uma Sankar
Determining the sign of $\Delta_{31}$ at long baseline neutrino experiments
Title changed and paper rewritten. 4 pages, 1 figure, revtex
Mod.Phys.Lett. A16 (2001) 1881-1886
10.1142/S0217732301004984
null
hep-ph
null
Recently it is advocated that high intensity and low energy $(E_\nu \sim 2 GeV)$ neutrino beams should be built to probe the $(13)$ mixing angle $\phi$ to a level of a few parts in $10^4$. Experiments using such beams will have better signal to background ratio in searches for $\nu_\mu \to \nu_e$ oscillations. We propose that such experiments can also determine the sign of $\Delta_{31}$ even if the beam consists of {\it neutrinos} only. By measuring the $\nu_\mu \to \nu_e$ transitions in two different energy ranges, the effects due to propagation of neutrinos through earth's crust can be isolated and the sign of $\Delta_{31}$ can be determined. If the sensitivity of an experiment to $\phi$ is $\epsilon$, then the same experiment is automatically sensitive to matter effects and the sign of $\Delta_{31}$ for values of $\phi \geq 2 \epsilon$.
[ { "created": "Fri, 24 Nov 2000 10:15:17 GMT", "version": "v1" }, { "created": "Wed, 23 May 2001 08:31:03 GMT", "version": "v2" } ]
2009-10-31
[ [ "Narayan", "Mohan", "" ], [ "Sankar", "S. Uma", "" ] ]
Recently it is advocated that high intensity and low energy $(E_\nu \sim 2 GeV)$ neutrino beams should be built to probe the $(13)$ mixing angle $\phi$ to a level of a few parts in $10^4$. Experiments using such beams will have better signal to background ratio in searches for $\nu_\mu \to \nu_e$ oscillations. We propose that such experiments can also determine the sign of $\Delta_{31}$ even if the beam consists of {\it neutrinos} only. By measuring the $\nu_\mu \to \nu_e$ transitions in two different energy ranges, the effects due to propagation of neutrinos through earth's crust can be isolated and the sign of $\Delta_{31}$ can be determined. If the sensitivity of an experiment to $\phi$ is $\epsilon$, then the same experiment is automatically sensitive to matter effects and the sign of $\Delta_{31}$ for values of $\phi \geq 2 \epsilon$.
hep-ph/0501167
Martin Schumacher
Martin Schumacher
Polarizability of the Nucleon and Compton Scattering
null
Prog.Part.Nucl.Phys.55:567-646,2005
10.1016/j.ppnp.2005.01.033
hep-ph/0501167
hep-ph
null
Different approaches to describe Compton scattering and the polarizability of the nucleon have been discussed up to now. We show that the most appropriate ones are provided by non-subtracted dispersion theories of the fixed-$t$ and fixed-$\theta$ types, where the properties of these two versions are complementary so that advantage can be taken from both of them. In the frame of fixed-$t$ dispersion theory it was possible to precisely reproduce experimental differential cross sections obtained for the proton in a wide angular range and for energies up to 1 GeV. At energies of the first resonance region and below, precise values for the electromagnetic polarizabilities and spin-polarizabilities have been determined for the proton and the neutron. The data show that diamagnetism is a prominent property of nucleon structure, where the underlying mechanism is a $t$-channel $\sigma$-meson exchange. A similar mechanism is responsible for the backward spin-polarizability where the relevant meson is the $\pi^0$. It is a challenge for further research to integrate the $\sigma$ and $\pi^0$ intermediate states into a consistent description of the structure of the nucleon.
[ { "created": "Tue, 18 Jan 2005 15:54:46 GMT", "version": "v1" }, { "created": "Tue, 15 Feb 2005 10:25:07 GMT", "version": "v2" }, { "created": "Mon, 28 Feb 2005 12:11:22 GMT", "version": "v3" } ]
2013-06-26
[ [ "Schumacher", "Martin", "" ] ]
Different approaches to describe Compton scattering and the polarizability of the nucleon have been discussed up to now. We show that the most appropriate ones are provided by non-subtracted dispersion theories of the fixed-$t$ and fixed-$\theta$ types, where the properties of these two versions are complementary so that advantage can be taken from both of them. In the frame of fixed-$t$ dispersion theory it was possible to precisely reproduce experimental differential cross sections obtained for the proton in a wide angular range and for energies up to 1 GeV. At energies of the first resonance region and below, precise values for the electromagnetic polarizabilities and spin-polarizabilities have been determined for the proton and the neutron. The data show that diamagnetism is a prominent property of nucleon structure, where the underlying mechanism is a $t$-channel $\sigma$-meson exchange. A similar mechanism is responsible for the backward spin-polarizability where the relevant meson is the $\pi^0$. It is a challenge for further research to integrate the $\sigma$ and $\pi^0$ intermediate states into a consistent description of the structure of the nucleon.
1601.04024
A. A. Natale
A. Doff and A. A. Natale
Schwinger-Dyson approach and its application to generate a light composite scalar
35 pages, 6 figures, few typos corrected. Version to appear in IJMPA
null
10.1142/S0217751X1650024X
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We discuss the possibility of generating a light composite scalar boson, in a scenario that we may generically call Technicolor, or in any variation of a strongly interacting theory, where by light we mean a scalar composite mass about one order of magnitude below the characteristic scale of the strong theory. Instead of most of the studies about a composite Higgs boson, which are based on effective Lagrangians, we consider this problem in the framework of non-perturbative solutions of the fermionic Schwinger-Dyson and Bethe-Salpeter equations. We study a range of mechanisms proposed during the recent years to form such light composite boson, and verify that such possibility seems to be necessarily associated to a fermionic self-energy that decreases slowly with the momentum.
[ { "created": "Fri, 15 Jan 2016 18:13:55 GMT", "version": "v1" }, { "created": "Wed, 24 Feb 2016 13:56:18 GMT", "version": "v2" } ]
2016-02-25
[ [ "Doff", "A.", "" ], [ "Natale", "A. A.", "" ] ]
We discuss the possibility of generating a light composite scalar boson, in a scenario that we may generically call Technicolor, or in any variation of a strongly interacting theory, where by light we mean a scalar composite mass about one order of magnitude below the characteristic scale of the strong theory. Instead of most of the studies about a composite Higgs boson, which are based on effective Lagrangians, we consider this problem in the framework of non-perturbative solutions of the fermionic Schwinger-Dyson and Bethe-Salpeter equations. We study a range of mechanisms proposed during the recent years to form such light composite boson, and verify that such possibility seems to be necessarily associated to a fermionic self-energy that decreases slowly with the momentum.
hep-ph/9703201
null
I.A. Shushpanov, A.V. Smilga
Quark condensate in a magnetic field
13 pages LaTeX, 5 postscript files for figures
Phys.Lett.B402:351-358,1997
10.1016/S0370-2693(97)00441-3
ITEP-TH-6/97, TPI-MINN-97/04, NUC-MINN-97/2-T
hep-ph hep-th
null
We study the dependence of quark condensate $\Sigma$ on an external magnetic field. For weak fields, it rises linearly with the field. Pion mass and residue are also shifted so that the Gell-Mann - Oakes - Renner relation is satisfied. In the strong field region, $\Sigma(H) \propto (eH)^{3/2}$.
[ { "created": "Fri, 28 Feb 1997 01:25:53 GMT", "version": "v1" } ]
2008-11-26
[ [ "Shushpanov", "I. A.", "" ], [ "Smilga", "A. V.", "" ] ]
We study the dependence of quark condensate $\Sigma$ on an external magnetic field. For weak fields, it rises linearly with the field. Pion mass and residue are also shifted so that the Gell-Mann - Oakes - Renner relation is satisfied. In the strong field region, $\Sigma(H) \propto (eH)^{3/2}$.
hep-ph/0403307
Orhan Cakir
O. Cakir (Ankara University, Ankara, Turkey), A. Yilmaz (Ankara University, Ankara, Turkey), S. Sultansoy (Gazi University, Ankara, Turkey and Institute of Physics, Baku, Azerbaijan)
Single production of excited electrons at future e^-e^+, ep and pp colliders
11 pages, 11 figures, 3 tables
Phys.Rev. D70 (2004) 075011
10.1103/PhysRevD.70.075011
null
hep-ph
null
We analyzed the potential of the LC with $\sqrt{s}=0.5$ TeV, LC$\times$LHC based ep collider with $\sqrt{s}=3.74$ TeV and LHC with $\sqrt{s}=14$ TeV to search for excited electrons through transition magnetic type couplings with gauge bosons. The $e^{\star}\to e\gamma$ signal and corresponding backgrounds are studied in detail.
[ { "created": "Wed, 31 Mar 2004 19:26:03 GMT", "version": "v1" }, { "created": "Mon, 5 Apr 2004 16:26:18 GMT", "version": "v2" }, { "created": "Thu, 22 Apr 2004 11:14:38 GMT", "version": "v3" }, { "created": "Sat, 12 Jun 2004 15:38:41 GMT", "version": "v4" }, { "created": "Tue, 20 Jul 2004 06:41:42 GMT", "version": "v5" } ]
2009-11-10
[ [ "Cakir", "O.", "", "Ankara University, Ankara, Turkey" ], [ "Yilmaz", "A.", "", "Ankara\n University, Ankara, Turkey" ], [ "Sultansoy", "S.", "", "Gazi University, Ankara, Turkey\n and Institute of Physics, Baku, Azerbaijan" ] ]
We analyzed the potential of the LC with $\sqrt{s}=0.5$ TeV, LC$\times$LHC based ep collider with $\sqrt{s}=3.74$ TeV and LHC with $\sqrt{s}=14$ TeV to search for excited electrons through transition magnetic type couplings with gauge bosons. The $e^{\star}\to e\gamma$ signal and corresponding backgrounds are studied in detail.
1009.2504
Gabriela Barenboim
Gabriela Barenboim
Gravity triggered neutrino condensates
16 pages, 10 figures
Phys.Rev.D82:093014,2010
10.1103/PhysRevD.82.093014
FTUV 10-0915
hep-ph astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this work we use the Schwinger-Dyson equations to study the possibility that an enhanced gravitational attraction triggers the formation of a right handed neutrino condensate, inducing dynamical symmetry breaking and generating a Majorana mass for the right handed neutrino at a scale appropriate for the see-saw mechanism. The composite field formed by the condensate phase could drive an early epoch of inflation. We find that to the lowest order, the theory does not allow dynamical symmetry breaking. Nevertheless, thanks to the large number of matter fields in the model, the suppression by additional powers in G of higher order terms can be compensated, boosting them up to their lowest order counterparts. This way chiral symmetry can be broken dynamically and the infrared mass generated turns out to be in the expected range for a successful see-saw scenario.
[ { "created": "Mon, 13 Sep 2010 20:00:31 GMT", "version": "v1" } ]
2010-12-23
[ [ "Barenboim", "Gabriela", "" ] ]
In this work we use the Schwinger-Dyson equations to study the possibility that an enhanced gravitational attraction triggers the formation of a right handed neutrino condensate, inducing dynamical symmetry breaking and generating a Majorana mass for the right handed neutrino at a scale appropriate for the see-saw mechanism. The composite field formed by the condensate phase could drive an early epoch of inflation. We find that to the lowest order, the theory does not allow dynamical symmetry breaking. Nevertheless, thanks to the large number of matter fields in the model, the suppression by additional powers in G of higher order terms can be compensated, boosting them up to their lowest order counterparts. This way chiral symmetry can be broken dynamically and the infrared mass generated turns out to be in the expected range for a successful see-saw scenario.
hep-ph/0007178
David London
D. Atwood, C.P. Burgess, E. Filotas, F. Leblond, D. London and I. Maksymyk
Supersymmetric Large Extra Dimensions Are Small and/or Numerous
31 pages, LaTeX, 7 figures, text slightly rewritten, figures updated, conclusions unchanged
Phys.Rev. D63 (2001) 025007
10.1103/PhysRevD.63.025007
AMES-HET-00-08, McGill-00/20, UdeM-GPP-TH-98-48
hep-ph hep-th
null
Recently, a scenario has been proposed in which the gravitational scale could be as low as the TeV scale, and extra dimensions could be large and detectable at the electroweak scale. Although supersymmetry is not a requirement of this scenario, it is nevertheless true that its best-motivated realizations arise in supersymmetric theories (like M theory). We argue here that supersymmetry can have robust, and in some instances fatal, implications for the expected experimental signature for TeV-scale gravity. The signature of the supersymmetric version of the scenario differs most dramatically from what has been considered in the literature because mass splittings within the gravity supermultiplet in these models are extremely small, implying in particular the existence of a very light spin-one superpartner for the graviton. We compute the implications of this graviphoton, and show that it can acquire dimension-four couplings to ordinary matter which can strongly conflict with supernova bounds.
[ { "created": "Mon, 17 Jul 2000 18:24:12 GMT", "version": "v1" }, { "created": "Mon, 16 Oct 2000 19:01:24 GMT", "version": "v2" } ]
2009-10-31
[ [ "Atwood", "D.", "" ], [ "Burgess", "C. P.", "" ], [ "Filotas", "E.", "" ], [ "Leblond", "F.", "" ], [ "London", "D.", "" ], [ "Maksymyk", "I.", "" ] ]
Recently, a scenario has been proposed in which the gravitational scale could be as low as the TeV scale, and extra dimensions could be large and detectable at the electroweak scale. Although supersymmetry is not a requirement of this scenario, it is nevertheless true that its best-motivated realizations arise in supersymmetric theories (like M theory). We argue here that supersymmetry can have robust, and in some instances fatal, implications for the expected experimental signature for TeV-scale gravity. The signature of the supersymmetric version of the scenario differs most dramatically from what has been considered in the literature because mass splittings within the gravity supermultiplet in these models are extremely small, implying in particular the existence of a very light spin-one superpartner for the graviton. We compute the implications of this graviphoton, and show that it can acquire dimension-four couplings to ordinary matter which can strongly conflict with supernova bounds.
1201.5804
J\"org Rittinger
P. A. Baikov, K. G. Chetyrkin, J. H. K\"uhn, J. Rittinger
Complete QCD Corrections to Hadronic $Z$--Decays in Order $\alpha_s^4$
null
null
10.1103/PhysRevLett.108.222003
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Corrections of order $\alpha_s^4$ for the axial singlet contributions for the decay rates of the $Z$-boson into hadrons are evaluated in the limit of the heavy top quark mass. Combined with recently finished ${\cal O}(\alpha_s^4)$ calculations of the non-signlet corrections, the new results directly lead us to the first {\em complete} ${\cal O}(\alpha_s^4)$ prediction for the total hadronic decay rate of the Z-boson. The new ${\cal O}(\alpha_s^4)$ term in Z-decay rate lead to a significant stabilization of the perturbative series, to a reduction of the theory uncertainty in the strong coupling constant $\alpha_s$, as extracted from these measurements, and to a small shift of the central value.
[ { "created": "Fri, 27 Jan 2012 15:48:50 GMT", "version": "v1" }, { "created": "Wed, 22 Feb 2012 13:36:36 GMT", "version": "v2" }, { "created": "Wed, 2 May 2012 07:19:21 GMT", "version": "v3" } ]
2015-06-03
[ [ "Baikov", "P. A.", "" ], [ "Chetyrkin", "K. G.", "" ], [ "Kühn", "J. H.", "" ], [ "Rittinger", "J.", "" ] ]
Corrections of order $\alpha_s^4$ for the axial singlet contributions for the decay rates of the $Z$-boson into hadrons are evaluated in the limit of the heavy top quark mass. Combined with recently finished ${\cal O}(\alpha_s^4)$ calculations of the non-signlet corrections, the new results directly lead us to the first {\em complete} ${\cal O}(\alpha_s^4)$ prediction for the total hadronic decay rate of the Z-boson. The new ${\cal O}(\alpha_s^4)$ term in Z-decay rate lead to a significant stabilization of the perturbative series, to a reduction of the theory uncertainty in the strong coupling constant $\alpha_s$, as extracted from these measurements, and to a small shift of the central value.
hep-ph/0510006
Stefan Sint
Stefan Sint
The Kaon B-parameter in quenched QCD
4 pages, parallel talk at International Conference on QCD and Hadronic Physics, Beijing, June 2005
Int.J.Mod.Phys. A21 (2006) 865-868
10.1142/S0217751X06032186
IFT-UAM-CSIC/05-40
hep-ph
null
I report on a recent determination by the ALPHA collaboration of the kaon B-parameter using lattice QCD with Wilson type quarks. An effort is made to control all systematic errors except for the quenched approximation. The preliminary result for the renormalization group invariant parameter is $\hat{B}_K = 0.834(37)$, which translates to $B_K^MSbar(2 GeV)=0.604(27)$ in the MSbar scheme with anticommuting $\gamma_5$.
[ { "created": "Sun, 2 Oct 2005 00:53:23 GMT", "version": "v1" } ]
2009-11-11
[ [ "Sint", "Stefan", "" ] ]
I report on a recent determination by the ALPHA collaboration of the kaon B-parameter using lattice QCD with Wilson type quarks. An effort is made to control all systematic errors except for the quenched approximation. The preliminary result for the renormalization group invariant parameter is $\hat{B}_K = 0.834(37)$, which translates to $B_K^MSbar(2 GeV)=0.604(27)$ in the MSbar scheme with anticommuting $\gamma_5$.
hep-ph/9705403
Michael Spira
Michael Spira
Squark and Gluino Production at Hadron Colliders
6 pages, latex, 5 figures, Invited talk given at XXXIInd Rencontre de Moriond: QCD and High Energy Hadronic Interactions, Les Arcs, France, March 22--29, 1997
null
null
CERN-TH/97-110
hep-ph
null
The determination of the full SUSY QCD corrections to the production of squarks and gluinos at hadron colliders is reviewed. The inclusion of the NLO corrections stabilizes the theoretical predictions of the various production cross sections significantly and leads to sizeable enhancements of the most relevant cross sections. We discuss the phenomenological consequences of the results on present and future experimental analyses. Finally we investigate the impact of the corrections on the transverse momentum and rapidity distributions.
[ { "created": "Fri, 23 May 1997 11:05:05 GMT", "version": "v1" } ]
2007-05-23
[ [ "Spira", "Michael", "" ] ]
The determination of the full SUSY QCD corrections to the production of squarks and gluinos at hadron colliders is reviewed. The inclusion of the NLO corrections stabilizes the theoretical predictions of the various production cross sections significantly and leads to sizeable enhancements of the most relevant cross sections. We discuss the phenomenological consequences of the results on present and future experimental analyses. Finally we investigate the impact of the corrections on the transverse momentum and rapidity distributions.
1706.03783
Adam Falkowski
Adam Falkowski, Mart\'in Gonz\'alez-Alonso, Kin Mimouni
Compilation of low-energy constraints on 4-fermion operators in the SMEFT
39 pages; full correlation matrix and likelihood function available in Mathematica notebook at https://www.dropbox.com/s/26nh71oebm4o12k/SMEFTlikelihood.nb?dl=0 v2: comments and references added, translation to Warsaw basis provided in notebook; v3: references added
null
10.1007/JHEP08(2017)123
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We compile information from low-energy observables sensitive to flavor-conserving 4-fermion operators with two or four leptons. Our analysis includes data from e+e- colliders, neutrino scattering on electron or nucleon targets, atomic parity violation, parity-violating electron scattering, and the decay of pions, neutrons, nuclei and tau leptons. We recast these data as tree-level constraints on 4-fermion operators in the Standard Model Effective Field Theory (SMEFT) where the SM Lagrangian is extended by dimension-6 operators. We allow all independent dimension-6 operators to be simultaneously present with an arbitrary flavor structure. The results are presented as a multi-dimensional likelihood function in the space of dimension-6 Wilson coefficients, which retains information about the correlations. In this form, the results can be readily used to place limits on masses and couplings in a large class of new physics theories.
[ { "created": "Mon, 12 Jun 2017 18:00:10 GMT", "version": "v1" }, { "created": "Thu, 29 Jun 2017 14:57:46 GMT", "version": "v2" }, { "created": "Fri, 1 Sep 2017 16:25:14 GMT", "version": "v3" } ]
2017-09-13
[ [ "Falkowski", "Adam", "" ], [ "González-Alonso", "Martín", "" ], [ "Mimouni", "Kin", "" ] ]
We compile information from low-energy observables sensitive to flavor-conserving 4-fermion operators with two or four leptons. Our analysis includes data from e+e- colliders, neutrino scattering on electron or nucleon targets, atomic parity violation, parity-violating electron scattering, and the decay of pions, neutrons, nuclei and tau leptons. We recast these data as tree-level constraints on 4-fermion operators in the Standard Model Effective Field Theory (SMEFT) where the SM Lagrangian is extended by dimension-6 operators. We allow all independent dimension-6 operators to be simultaneously present with an arbitrary flavor structure. The results are presented as a multi-dimensional likelihood function in the space of dimension-6 Wilson coefficients, which retains information about the correlations. In this form, the results can be readily used to place limits on masses and couplings in a large class of new physics theories.
hep-ph/9812494
Naveen Gaur
Ashok Goyal, V.K.Gupta, Kanupriya and Vinita Tuli
Nuclear Matter in Intense Magnetic Field and Weak Processes
29 pages (LaTeX) including 7 figures
Int.J.Mod.Phys. A16 (2001) 347-368
10.1142/S0217751X01003019
null
hep-ph
null
We study the effect of magnetic field on the dominant neutrino emission processes in neutron stars.The processes are first calculated for the case when the magnetic field does not exceed the critical value to confine electrons to the lowest Landau state.We then consider the more important case of intense magnetic field to evaluate the direct URCA and the neutronisation processes. In order to estimate the effect we derive the composition of cold nuclear matter at high densities and in beta equilibrium, a situation appropriate for neutron stars. The hadronic interactions are incorporated through the exchange of scalar and vector mesons in the frame work of relativistic mean field theory. In addition the effects of anomalous magnetic moments of nucleons are also considered.
[ { "created": "Thu, 24 Dec 1998 11:32:55 GMT", "version": "v1" } ]
2015-06-25
[ [ "Goyal", "Ashok", "" ], [ "Gupta", "V. K.", "" ], [ "Kanupriya", "", "" ], [ "Tuli", "Vinita", "" ] ]
We study the effect of magnetic field on the dominant neutrino emission processes in neutron stars.The processes are first calculated for the case when the magnetic field does not exceed the critical value to confine electrons to the lowest Landau state.We then consider the more important case of intense magnetic field to evaluate the direct URCA and the neutronisation processes. In order to estimate the effect we derive the composition of cold nuclear matter at high densities and in beta equilibrium, a situation appropriate for neutron stars. The hadronic interactions are incorporated through the exchange of scalar and vector mesons in the frame work of relativistic mean field theory. In addition the effects of anomalous magnetic moments of nucleons are also considered.
hep-ph/9810244
Kirill Levtchenko
V.Ch. Zhukovskii, K. G. Levtchenko, T. L. Shoniya, P.A. Eminov
Radiative Shift of the Quark Mass in a Constant Chromomagnetic Field at Finite Temperature and Density
9 pages, LaTeX
Vestn.Mosk.Univ.Fiz.Astron. 51 (1996) 1-6
null
null
hep-ph
null
The radiation shift of the quark mass in a constant chromomagnetic field at finite temperature and density was calculated. The limiting cases of a weak and a strong chromomagnetic field were considered. It was shown that in a strong field there is no imaginary part in the contribution of the finite density effects to the quark mass shift, and its real part can considerably exceed the corresponding part of the purely field contribution.
[ { "created": "Mon, 5 Oct 1998 10:09:29 GMT", "version": "v1" } ]
2007-05-23
[ [ "Zhukovskii", "V. Ch.", "" ], [ "Levtchenko", "K. G.", "" ], [ "Shoniya", "T. L.", "" ], [ "Eminov", "P. A.", "" ] ]
The radiation shift of the quark mass in a constant chromomagnetic field at finite temperature and density was calculated. The limiting cases of a weak and a strong chromomagnetic field were considered. It was shown that in a strong field there is no imaginary part in the contribution of the finite density effects to the quark mass shift, and its real part can considerably exceed the corresponding part of the purely field contribution.
1408.3761
Vladimir Karmanov
J. Carbonell and V.A. Karmanov
Solving Bethe-Salpeter scattering state equation in Minkowski space
24 pages, 12 figures, to be published in Phys. Rev. D
null
10.1103/PhysRevD.90.056002
null
hep-ph hep-th nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a method to directly solving the Bethe-Salpeter equation in Minkowski space, both for bound and scattering states. It is based on a proper treatment of the singularities which appear in the kernel, propagators and Bethe-Salpeter amplitude itself. The off-mass shell scattering amplitude for spinless particles interacting by a one boson exchange is computed for the first time.
[ { "created": "Sat, 16 Aug 2014 18:56:41 GMT", "version": "v1" } ]
2015-06-22
[ [ "Carbonell", "J.", "" ], [ "Karmanov", "V. A.", "" ] ]
We present a method to directly solving the Bethe-Salpeter equation in Minkowski space, both for bound and scattering states. It is based on a proper treatment of the singularities which appear in the kernel, propagators and Bethe-Salpeter amplitude itself. The off-mass shell scattering amplitude for spinless particles interacting by a one boson exchange is computed for the first time.
hep-ph/0210316
Gabriel Sanchez-Colon
G. Sanchez-Colon, R. Huerta and A. Garcia
Mirror matter admixtures in \Omega^- two body non-leptonic decays and the \Delta I = 1/2 rule
Content changed
J.Phys. G29 (2003) L15-L20
10.1088/0954-3899/29/3/101
null
hep-ph
null
We extend our previous analysis of mirror matter admixtures to reproduce the |\Delta I|=1/2 rule predictions in the decays \Omega^-\to\Xi^-\pi^0, \Omega^-\to\Xi^0\pi^-, and \Omega^-\to\Lambda K^-. The results are satisfactory, lending credibility to the possibility that the enhancement phenomenon may be attributed to such admixtures.
[ { "created": "Wed, 23 Oct 2002 15:39:16 GMT", "version": "v1" }, { "created": "Thu, 5 Dec 2002 19:05:41 GMT", "version": "v2" } ]
2018-10-25
[ [ "Sanchez-Colon", "G.", "" ], [ "Huerta", "R.", "" ], [ "Garcia", "A.", "" ] ]
We extend our previous analysis of mirror matter admixtures to reproduce the |\Delta I|=1/2 rule predictions in the decays \Omega^-\to\Xi^-\pi^0, \Omega^-\to\Xi^0\pi^-, and \Omega^-\to\Lambda K^-. The results are satisfactory, lending credibility to the possibility that the enhancement phenomenon may be attributed to such admixtures.
hep-ph/0211042
Bhaskar Dutta
R. Arnowitt and B. Dutta
Dark matter and Consequences of SUSY
11 pages, latex, 10 figures, Plenary talk at SUSY02 (DESY, June 17-23, 2002)
null
null
null
hep-ph astro-ph
null
We examine here the constraints from the amount of relic density of neutralino dark matter and other experiments have on the SUSY parameter space for the mSUGRA model and for models with non-universal soft breaking at the GUT scale. In mSUGRA, the allowed amount of dark matter restricts the SUSY parameter space to a narrow band in m_0 - m_{1/2} (except at very large \tan\beta). The Higgs mass and b-> s\gamma constraints produce a lower bound of m_{1/2}>~{\sim} 300GeV and if the muon magnetic moment anomaly can be interpreted as a 3\sigma deviation from the Standard Model, one also obtains an upper bound of m_{1/2} <~900 GeV, making the SUSY spectrum well accessible to the LHC. The B_s->\mu \mu decay is seen to be accessible to the Tevatron Run2B with 15 fb^{-1} for \tan\beta>~30. However, only parts of the spectrum will be accessible to the NLC if it's energy is below 800GeV. Non-universal soft breaking opens new regions of parameter space. Thus the m_{1/2} lower bound constraint of b->s\gamma and also the Higgs mass can be reduced greatly if the gluino mass is assumed larger at the GUT scale (allowing for a lighter gaugino spectrum), and non-universal Higgs soft breaking masses at the GUT scale can open new allowed regions at relatively low m_{1/2} and high m_0 where dark matter detection cross sections may be increased by a factor of ten or more.
[ { "created": "Mon, 4 Nov 2002 19:59:52 GMT", "version": "v1" } ]
2007-05-23
[ [ "Arnowitt", "R.", "" ], [ "Dutta", "B.", "" ] ]
We examine here the constraints from the amount of relic density of neutralino dark matter and other experiments have on the SUSY parameter space for the mSUGRA model and for models with non-universal soft breaking at the GUT scale. In mSUGRA, the allowed amount of dark matter restricts the SUSY parameter space to a narrow band in m_0 - m_{1/2} (except at very large \tan\beta). The Higgs mass and b-> s\gamma constraints produce a lower bound of m_{1/2}>~{\sim} 300GeV and if the muon magnetic moment anomaly can be interpreted as a 3\sigma deviation from the Standard Model, one also obtains an upper bound of m_{1/2} <~900 GeV, making the SUSY spectrum well accessible to the LHC. The B_s->\mu \mu decay is seen to be accessible to the Tevatron Run2B with 15 fb^{-1} for \tan\beta>~30. However, only parts of the spectrum will be accessible to the NLC if it's energy is below 800GeV. Non-universal soft breaking opens new regions of parameter space. Thus the m_{1/2} lower bound constraint of b->s\gamma and also the Higgs mass can be reduced greatly if the gluino mass is assumed larger at the GUT scale (allowing for a lighter gaugino spectrum), and non-universal Higgs soft breaking masses at the GUT scale can open new allowed regions at relatively low m_{1/2} and high m_0 where dark matter detection cross sections may be increased by a factor of ten or more.
1708.07594
Peter Athron
Peter Athron (on behalf of the GAMBIT collaboration)
SUSY Global Fits
6 pages, 5 figures, proceedings for the 5th annual conference on Large Hadron Collider Physics (LHCP2017), v2 added missing Refs
null
null
CoEPP-MN-17-14, gambit-proceedings-2017
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present comprehensive global fits of supersymmetric (SUSY) models from the Global and Modular Beyond-the-Standard-Model Inference Tool (GAMBIT) collaboration, based on arXiv:1705.07935 and arXiv:1705.07917. We investigate several variants of the minimal supersymmetric standard model, a fully constrained version (CMSSM) with universal scalar ($m_0$), gaugino ($m_{1/2}$) and trilinear masses ($A_0$) at the gauge coupling unification scale, a similar model that is relaxed by adding an extra parameter for the soft Higgs masses (NUHM1), another where the soft Higgs masses are also split (NUHM2) and finally a weak scale MSSM7 model. We use the public GAMBIT global fitting framework and take into account all relevant data to reveal the regions of parameter space with the highest likelihood. Our results reveal that all models have very heavy scenarios that are well out of reach of the LHC, but will be probed by forthcoming dark matter experiments, as well as a stop-co-annihilation region which has better prospects for detection in collider experiments. The stau co-annihilation region is excluded from the CMSSM at $2 \sigma$ but is present in the NUHM1 and NUHM2 variants. Finally by relaxing constraints in the NUHM1, NUHM2 and MSSM7 we see additional regions appear: lighter chargino co-annihilation region, sbottom co-annihilation and $h/Z$ funnels.
[ { "created": "Fri, 25 Aug 2017 01:45:32 GMT", "version": "v1" }, { "created": "Sun, 5 Nov 2017 14:37:16 GMT", "version": "v2" } ]
2020-08-12
[ [ "Athron", "Peter", "", "on behalf of the GAMBIT collaboration" ] ]
We present comprehensive global fits of supersymmetric (SUSY) models from the Global and Modular Beyond-the-Standard-Model Inference Tool (GAMBIT) collaboration, based on arXiv:1705.07935 and arXiv:1705.07917. We investigate several variants of the minimal supersymmetric standard model, a fully constrained version (CMSSM) with universal scalar ($m_0$), gaugino ($m_{1/2}$) and trilinear masses ($A_0$) at the gauge coupling unification scale, a similar model that is relaxed by adding an extra parameter for the soft Higgs masses (NUHM1), another where the soft Higgs masses are also split (NUHM2) and finally a weak scale MSSM7 model. We use the public GAMBIT global fitting framework and take into account all relevant data to reveal the regions of parameter space with the highest likelihood. Our results reveal that all models have very heavy scenarios that are well out of reach of the LHC, but will be probed by forthcoming dark matter experiments, as well as a stop-co-annihilation region which has better prospects for detection in collider experiments. The stau co-annihilation region is excluded from the CMSSM at $2 \sigma$ but is present in the NUHM1 and NUHM2 variants. Finally by relaxing constraints in the NUHM1, NUHM2 and MSSM7 we see additional regions appear: lighter chargino co-annihilation region, sbottom co-annihilation and $h/Z$ funnels.
hep-ph/0010116
Thomas Schaefer
Thomas Schaefer (Stony Brook and Riken-BNL) and Edward Shuryak (Stony Brook)
Implications of the ALEPH tau-Lepton Decay Data for Perturbative and Non-Perturbative QCD
4 pages, 6 figures
Phys.Rev.Lett. 86 (2001) 3973-3976
10.1103/PhysRevLett.86.3973
null
hep-ph hep-lat nucl-th
null
We use ALEPH data on hadronic $\tau$ decays in order to calculate Euclidean coordinate space correlation functions in the vector and axial-vector channels. The linear combination $V-A$ receives no perturbative contribution and is quantitatively reproduced by the instanton liquid model. In the case of $V+A$ the instanton calculation is in good agreement with the data once perturbative corrections are included. These corrections clearly show the evolution of $\alpha_s$. We also analyze the range of validity of the Operator Product Expansion (OPE). In the $V-A$ channel we find a dimension $d=6$ contribution which is comparable to the original SVZ estimate, but the instanton model provides a different non-singular term of the same magnitude. In the $V+A$ case both the OPE and the instanton model predict the same $d=4$ power correction induced by the gluon condensate, but it is masked by much larger perturbative contributions. We conclude that the range of validity of the OPE is limited to $x\lsim0.3$ fm, whereas the instanton model describes the data over the entire range.
[ { "created": "Wed, 11 Oct 2000 20:21:44 GMT", "version": "v1" } ]
2009-10-31
[ [ "Schaefer", "Thomas", "", "Stony Brook and Riken-BNL" ], [ "Shuryak", "Edward", "", "Stony\n Brook" ] ]
We use ALEPH data on hadronic $\tau$ decays in order to calculate Euclidean coordinate space correlation functions in the vector and axial-vector channels. The linear combination $V-A$ receives no perturbative contribution and is quantitatively reproduced by the instanton liquid model. In the case of $V+A$ the instanton calculation is in good agreement with the data once perturbative corrections are included. These corrections clearly show the evolution of $\alpha_s$. We also analyze the range of validity of the Operator Product Expansion (OPE). In the $V-A$ channel we find a dimension $d=6$ contribution which is comparable to the original SVZ estimate, but the instanton model provides a different non-singular term of the same magnitude. In the $V+A$ case both the OPE and the instanton model predict the same $d=4$ power correction induced by the gluon condensate, but it is masked by much larger perturbative contributions. We conclude that the range of validity of the OPE is limited to $x\lsim0.3$ fm, whereas the instanton model describes the data over the entire range.
hep-ph/0107284
Olga Lugovskaya
Vladimir G. Baryshevsky, Olga M.Lugovskaya
Theoretical interpretation of the experiments on Parametric X-ray radiation in case of backward diffraction
Latex, 10 pages with 5 eps figure
null
null
null
hep-ph
null
The spectral-angular and angular distributions of parametric X-radiation for case of backward diffraction (particular case of Bragg geometry scheme) is discussed. It is shown that in case of Bragg geometry it is necessary to use dynamical approach for PXR consideration. The comparison of the theory and experiment is carried out.
[ { "created": "Fri, 27 Jul 2001 11:12:35 GMT", "version": "v1" } ]
2007-05-23
[ [ "Baryshevsky", "Vladimir G.", "" ], [ "Lugovskaya", "Olga M.", "" ] ]
The spectral-angular and angular distributions of parametric X-radiation for case of backward diffraction (particular case of Bragg geometry scheme) is discussed. It is shown that in case of Bragg geometry it is necessary to use dynamical approach for PXR consideration. The comparison of the theory and experiment is carried out.
1507.08278
Alfredo Valcarce
T.F. Carames, A. Valcarce
Heavy flavor dibaryons
13 pages, 6 figures. To appear in Phys. Rev. D. arXiv admin note: text overlap with arXiv:1204.5502, arXiv:1507.08046
null
10.1103/PhysRevD.92.034015
Phys. Rev. D 92, 034015 (2015)
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the two-baryon system with two units of charm looking for the possible existence of a loosely bound state resembling the $H$ dibaryon. We make use of a chiral constituent quark model tuned in the description of the baryon and meson spectra as well as the $NN$ interaction. The presence of the heavy quarks makes the interaction simpler than in light baryon systems. We analyze possible quark-Pauli effects that would be present in spin-isospin saturated channels. Our results point to the non-existence of a charmed $H$-like dibaryon, although it may appear as a resonance above the $\Lambda_c\Lambda_c$ threshold.
[ { "created": "Wed, 29 Jul 2015 17:27:56 GMT", "version": "v1" } ]
2015-08-17
[ [ "Carames", "T. F.", "" ], [ "Valcarce", "A.", "" ] ]
We study the two-baryon system with two units of charm looking for the possible existence of a loosely bound state resembling the $H$ dibaryon. We make use of a chiral constituent quark model tuned in the description of the baryon and meson spectra as well as the $NN$ interaction. The presence of the heavy quarks makes the interaction simpler than in light baryon systems. We analyze possible quark-Pauli effects that would be present in spin-isospin saturated channels. Our results point to the non-existence of a charmed $H$-like dibaryon, although it may appear as a resonance above the $\Lambda_c\Lambda_c$ threshold.
1110.5187
Hiroaki Kouno
Hiroaki Kouno, Mizuho Kishikawa, Takahiro Sasaki, Yuji Sakai and Masanobu Yahiro
Spontaneous parity and charge-conjugation violations at real isospin and imaginary baryon chemical potentials
12 pages, 18 figures. Typos were revised. Symbols /P and /C were added in Figures 8a and 8b. Colors of the figures were changed. Some sentences were added and revised
null
10.1103/PhysRevD.85.016001
SAGA-HE-269
hep-ph hep-lat nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The phase structure of two-flavor QCD is investigated at real isospin and imaginary quark chemical potentials by using the Polyakov-loop extended Nambu--Jona-Lasinio model. In the region, parity symmetry is spontaneously broken by the pion superfluidity phase transition, whereas charge-conjugation symmetry is spontaneously violated by the Roberge-Weiss transition. The chiral (deconfinement) crossover at zero isospin and quark chemical potentials is a remnant of the parity (charge-conjugation) violation. The interplay between the parity and charge-conjugation violations are analyzed, and it is investigated how the interplay is related to the correlation between the chiral and deconfinement crossovers at zero isospin and quark chemical potentials.
[ { "created": "Mon, 24 Oct 2011 10:21:38 GMT", "version": "v1" }, { "created": "Wed, 26 Oct 2011 10:50:25 GMT", "version": "v2" }, { "created": "Thu, 1 Dec 2011 08:47:30 GMT", "version": "v3" } ]
2013-05-30
[ [ "Kouno", "Hiroaki", "" ], [ "Kishikawa", "Mizuho", "" ], [ "Sasaki", "Takahiro", "" ], [ "Sakai", "Yuji", "" ], [ "Yahiro", "Masanobu", "" ] ]
The phase structure of two-flavor QCD is investigated at real isospin and imaginary quark chemical potentials by using the Polyakov-loop extended Nambu--Jona-Lasinio model. In the region, parity symmetry is spontaneously broken by the pion superfluidity phase transition, whereas charge-conjugation symmetry is spontaneously violated by the Roberge-Weiss transition. The chiral (deconfinement) crossover at zero isospin and quark chemical potentials is a remnant of the parity (charge-conjugation) violation. The interplay between the parity and charge-conjugation violations are analyzed, and it is investigated how the interplay is related to the correlation between the chiral and deconfinement crossovers at zero isospin and quark chemical potentials.
hep-ph/0403009
Hyun-Chul Kim H.-Ch. Kim
Seung-Il Nam, Atsushi Hosaka, and Hyun-Chul Kim
Photo-production of the pentaquark $\Theta^{+}$ with positive and negative parities
11 figures, 10 pages. Will be submitted to Phys. Rev. D
J.Korean Phys.Soc. 49 (2006) 1928
null
PNU-NTG-04/2004, PNU-NURI-03/2004
hep-ph
null
We investigate the production of the pentaquark $\Theta^+$ baryon via the $\gamma n\to K^-\Theta^+$ and $\gamma p\to \bar{K}^0 \Theta^+$ processes, focusing on the parity of the $\Theta^+$. Using the effective Lagrangians, we calculate the total and differential cross sections with the spin of the $\Theta^+$ presumed to be 1/2. We employ the coupling constant of the $KN\Theta$ vertex determined by assuming its mass and the decay width to be $1540 {\rm MeV}$ and $15 {\rm MeV}$. That of the $K^*N\Theta$ is taken to be about a half of the $KN\Theta$ coupling constant. We estimate the cutoff parameter by reproducing the total cross section of the $\gamma p \to K^+ \Lambda$ reaction. It turns out that the total cross section for the $\gamma n\to K^- \Theta^+$ process is about four times larger than that of the $\gamma p\to\bar{K}^0\Theta^+$. We also find that the cross sections for the production of the positive-parity $\Theta$ are about ten times as large as those for the negative-parity ones.
[ { "created": "Sun, 29 Feb 2004 14:50:19 GMT", "version": "v1" } ]
2007-05-23
[ [ "Nam", "Seung-Il", "" ], [ "Hosaka", "Atsushi", "" ], [ "Kim", "Hyun-Chul", "" ] ]
We investigate the production of the pentaquark $\Theta^+$ baryon via the $\gamma n\to K^-\Theta^+$ and $\gamma p\to \bar{K}^0 \Theta^+$ processes, focusing on the parity of the $\Theta^+$. Using the effective Lagrangians, we calculate the total and differential cross sections with the spin of the $\Theta^+$ presumed to be 1/2. We employ the coupling constant of the $KN\Theta$ vertex determined by assuming its mass and the decay width to be $1540 {\rm MeV}$ and $15 {\rm MeV}$. That of the $K^*N\Theta$ is taken to be about a half of the $KN\Theta$ coupling constant. We estimate the cutoff parameter by reproducing the total cross section of the $\gamma p \to K^+ \Lambda$ reaction. It turns out that the total cross section for the $\gamma n\to K^- \Theta^+$ process is about four times larger than that of the $\gamma p\to\bar{K}^0\Theta^+$. We also find that the cross sections for the production of the positive-parity $\Theta$ are about ten times as large as those for the negative-parity ones.
hep-ph/9504236
Grzegorz Wilk
Q.J.Liu, W.Q.Chao and G.Wilk
Energy and Atomic Mass Dependence of Nuclear Stopping Power in Relativistic Heavy-Ion Collisions in Interacting Gluon Model
10 pages in compressed uuencoded file
Mod.Phys.Lett. A10 (1995) 1905-1914
10.1142/S0217732395002052
null
hep-ph
null
We present a Monte-Carlo simulation of energy deposition process in relativistic heavy-ion collisions based on a new realization of the Interacting-Gluon-Model (IGM) for high energy $N-N$ collisions. In particular we show results for proton spectra from collisions of $E_{lab}=200 \ GeV/N$ $^{32}$S beam incident on $^{32}$S target and analyze the energy and mass dependence of nuclear stopping power predicted by our model. Theoretical predictions for proton rapidity distributions of both $^{208}$Pb + $^{208}$Pb collisions at $E_{lab}=160 \ GeV/N$ CERN SPS and $^{197}$Au + $^{197}$Au at $\sqrt{s_{NN}}=200 \ GeV$ BNL RHIC are given.
[ { "created": "Wed, 5 Apr 1995 10:34:15 GMT", "version": "v1" } ]
2015-06-25
[ [ "Liu", "Q. J.", "" ], [ "Chao", "W. Q.", "" ], [ "Wilk", "G.", "" ] ]
We present a Monte-Carlo simulation of energy deposition process in relativistic heavy-ion collisions based on a new realization of the Interacting-Gluon-Model (IGM) for high energy $N-N$ collisions. In particular we show results for proton spectra from collisions of $E_{lab}=200 \ GeV/N$ $^{32}$S beam incident on $^{32}$S target and analyze the energy and mass dependence of nuclear stopping power predicted by our model. Theoretical predictions for proton rapidity distributions of both $^{208}$Pb + $^{208}$Pb collisions at $E_{lab}=160 \ GeV/N$ CERN SPS and $^{197}$Au + $^{197}$Au at $\sqrt{s_{NN}}=200 \ GeV$ BNL RHIC are given.
1601.01681
Marek Lewicki
Marek Lewicki, Tanja Rindler-Daller and James D. Wells
Enabling Electroweak Baryogenesis through Dark Matter
null
Journal of High Energy Physics, Volume 2016, Issue 6, article id.55, 21 pp
10.1007/JHEP06(2016)055
MCTP-16-01
hep-ph astro-ph.CO hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the impact on electroweak baryogenesis from a swifter cosmological expansion induced by dark matter. We detail the experimental bounds that one can place on models that realize it, and we investigate the modifications of these bounds that result from a non-standard cosmological history. The modifications can be sizeable if the expansion rate of the Universe increases by several orders of magnitude. We illustrate the impact through the example of scalar field dark matter, which can alter the cosmological history enough to enable a strong-enough first-order phase transition in the Standard Model when it is supplemented by a dimension six operator directly modifying the Higgs boson potential. We show that due to the modified cosmological history, electroweak baryogenesis can be realized, while keeping deviations of the triple Higgs coupling below HL-LHC sensitivies. The required scale of new physics to effectuate a strong-enough first order phase transition can change by as much as twenty percent as the expansion rate increases by six orders of magnitude.
[ { "created": "Thu, 7 Jan 2016 21:00:01 GMT", "version": "v1" }, { "created": "Wed, 8 Jun 2016 11:50:20 GMT", "version": "v2" } ]
2016-12-01
[ [ "Lewicki", "Marek", "" ], [ "Rindler-Daller", "Tanja", "" ], [ "Wells", "James D.", "" ] ]
We study the impact on electroweak baryogenesis from a swifter cosmological expansion induced by dark matter. We detail the experimental bounds that one can place on models that realize it, and we investigate the modifications of these bounds that result from a non-standard cosmological history. The modifications can be sizeable if the expansion rate of the Universe increases by several orders of magnitude. We illustrate the impact through the example of scalar field dark matter, which can alter the cosmological history enough to enable a strong-enough first-order phase transition in the Standard Model when it is supplemented by a dimension six operator directly modifying the Higgs boson potential. We show that due to the modified cosmological history, electroweak baryogenesis can be realized, while keeping deviations of the triple Higgs coupling below HL-LHC sensitivies. The required scale of new physics to effectuate a strong-enough first order phase transition can change by as much as twenty percent as the expansion rate increases by six orders of magnitude.
hep-ph/0508069
Vishnu Bannur M
Vishnu M. Bannur
Quasi-particle model of QGP - a revisit
7 pages (LaTex), 6 figures, revised with correction and new results
Eur.Phys.J.C50:629-634,2007
10.1140/epjc/s10052-007-0233-7
null
hep-ph
null
The quasi-particle model of quark gluon plasma (QGP) is revisited here with thermodynamically consistent formalism, different from earlier studies, without the need of temperature dependent bag constant as well as other effects such as confinement effects, effective degrees of freedom etc. Our model has only one system dependent parameter and surpraisingly good fit to lattice results for gluon plasma, 2-flavor and 3-flavor QGP are obtained. The basic idea is to evaluate energy density $\epsilon$ first from grand partition function of quasi-particle QGP and then derive all other thermodynamic functions from $\epsilon$. Quasi-particles are assumed to have temperature dependent mass equal to plasma frequency. Energy density, pressure and speed of sound are evaluated and compared with available lattice data. We further extend the model to finite chemical potential, without any new parameters, to obtain quark density, quark susceptibility etc. and fits very well with the lattice results on 2-flavor QGP.
[ { "created": "Fri, 5 Aug 2005 09:18:31 GMT", "version": "v1" }, { "created": "Tue, 18 Oct 2005 09:05:29 GMT", "version": "v2" } ]
2010-10-27
[ [ "Bannur", "Vishnu M.", "" ] ]
The quasi-particle model of quark gluon plasma (QGP) is revisited here with thermodynamically consistent formalism, different from earlier studies, without the need of temperature dependent bag constant as well as other effects such as confinement effects, effective degrees of freedom etc. Our model has only one system dependent parameter and surpraisingly good fit to lattice results for gluon plasma, 2-flavor and 3-flavor QGP are obtained. The basic idea is to evaluate energy density $\epsilon$ first from grand partition function of quasi-particle QGP and then derive all other thermodynamic functions from $\epsilon$. Quasi-particles are assumed to have temperature dependent mass equal to plasma frequency. Energy density, pressure and speed of sound are evaluated and compared with available lattice data. We further extend the model to finite chemical potential, without any new parameters, to obtain quark density, quark susceptibility etc. and fits very well with the lattice results on 2-flavor QGP.
hep-ph/9703298
Ira Rothstein
Benjamin Grinstein and Ira Z. Rothstein
Effective Field Theory and Matching in Non-Relativistic Gauge Theories
11 pages LATEX. Version to appear in PRD. Paragraph regarding non-local four quark operators included. Comparison of magnetic moment operator scaling to other schemes removed. Discussion of the non-multipole expanded theory modified
Phys.Rev. D57 (1998) 78-82
10.1103/PhysRevD.57.78
null
hep-ph hep-lat nucl-th
null
The effective Lagrangian and power counting rules for non-relativistic gauge theories are derived via an expansion in $1/c$. It is shown that the $1/c$ expansion leads to an effective field theory which incorporates a multipole expansion. Failure to use this expansion in the low energy theory leads to a loss of predictive power as the matching procedure becomes intractable. It is emphasized that there is not a one-to-one correspondence between operators in the modified low energy theory and those in the heavy quark effective theory.We also discuss the Lamb shift as a pedagogical example of the power counting scheme.
[ { "created": "Tue, 11 Mar 1997 23:01:30 GMT", "version": "v1" }, { "created": "Wed, 30 Apr 1997 01:14:53 GMT", "version": "v2" }, { "created": "Wed, 15 Oct 1997 23:18:28 GMT", "version": "v3" } ]
2009-10-30
[ [ "Grinstein", "Benjamin", "" ], [ "Rothstein", "Ira Z.", "" ] ]
The effective Lagrangian and power counting rules for non-relativistic gauge theories are derived via an expansion in $1/c$. It is shown that the $1/c$ expansion leads to an effective field theory which incorporates a multipole expansion. Failure to use this expansion in the low energy theory leads to a loss of predictive power as the matching procedure becomes intractable. It is emphasized that there is not a one-to-one correspondence between operators in the modified low energy theory and those in the heavy quark effective theory.We also discuss the Lamb shift as a pedagogical example of the power counting scheme.
2211.09922
Aldo Ejlli
Aldo Ejlli, Sander M. Vermeulen, Eyal Schwartz, Lorenzo Aiello, and Hartmut Grote
Probing dark matter with polarimetry techniques
null
Physical Review D 107, 083035 (2023)
10.1103/PhysRevD.107.083035
null
hep-ph astro-ph.IM
http://creativecommons.org/licenses/by/4.0/
In this work, we propose polarimetry experiments to search for low-mass (sub-eV) bosonic field dark matter, including axions and axion-like particles. We show that a polarimetry configuration consisting of a thick birefringent solid inside a Fabry-P\'erot cavity is exceptionally sensitive to scalar field dark matter, which may cause oscillatory variations in the solid's thickness and refractive index. In addition, we show that a reconfiguration of this polarimetry experiment, in which two quarter-wave plates are placed inside the Fabry-P\'erot cavity instead of a thick birefringent solid, is very sensitive to axion-like particles. We investigate the possibility of using cross-correlation of twin polarimeters to increase the sensitivity of the experiment, which in turn could allow us to explore unexplored parts of the parameter space and potentially detect a signal in either dark matter scenario.
[ { "created": "Thu, 17 Nov 2022 22:49:16 GMT", "version": "v1" }, { "created": "Tue, 2 May 2023 13:24:14 GMT", "version": "v2" } ]
2023-05-03
[ [ "Ejlli", "Aldo", "" ], [ "Vermeulen", "Sander M.", "" ], [ "Schwartz", "Eyal", "" ], [ "Aiello", "Lorenzo", "" ], [ "Grote", "Hartmut", "" ] ]
In this work, we propose polarimetry experiments to search for low-mass (sub-eV) bosonic field dark matter, including axions and axion-like particles. We show that a polarimetry configuration consisting of a thick birefringent solid inside a Fabry-P\'erot cavity is exceptionally sensitive to scalar field dark matter, which may cause oscillatory variations in the solid's thickness and refractive index. In addition, we show that a reconfiguration of this polarimetry experiment, in which two quarter-wave plates are placed inside the Fabry-P\'erot cavity instead of a thick birefringent solid, is very sensitive to axion-like particles. We investigate the possibility of using cross-correlation of twin polarimeters to increase the sensitivity of the experiment, which in turn could allow us to explore unexplored parts of the parameter space and potentially detect a signal in either dark matter scenario.
0809.1795
Yury Kalinovsky L.
Yu. L. Kalinovsky, M. K. Volkov
Two photon decays of scalar mesons in the quark NJL model
6 pages, 1 figure
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Two photon decays of scalar mesons f_0(980), a_0(980), \sigma(600) in the quark Nambu - Jona - Lasinio (NJL) model are calculated. The contributions of the meson loops are taken into account along with the quark loops (Hartree - Fock approximation). This corresponds to the next order of the 1/N_c expansion, where N_c=3 is the number of quark colors. It is shown that the meson and quark loops give comparable contributions to the amplitude. Moreover, in the process f_0(980)-> \gamma \gamma the kaon loop plays the dominant role. A similar situation takes place in the decay \phi -> f_0(980) \gamma \cite{physrev}. Our results are in satisfactory agreement with the recent experimental data.
[ { "created": "Wed, 10 Sep 2008 13:41:15 GMT", "version": "v1" } ]
2008-09-11
[ [ "Kalinovsky", "Yu. L.", "" ], [ "Volkov", "M. K.", "" ] ]
Two photon decays of scalar mesons f_0(980), a_0(980), \sigma(600) in the quark Nambu - Jona - Lasinio (NJL) model are calculated. The contributions of the meson loops are taken into account along with the quark loops (Hartree - Fock approximation). This corresponds to the next order of the 1/N_c expansion, where N_c=3 is the number of quark colors. It is shown that the meson and quark loops give comparable contributions to the amplitude. Moreover, in the process f_0(980)-> \gamma \gamma the kaon loop plays the dominant role. A similar situation takes place in the decay \phi -> f_0(980) \gamma \cite{physrev}. Our results are in satisfactory agreement with the recent experimental data.
hep-ph/0612287
David Morrissey
Gordon L. Kane, Piyush Kumar, David E. Morrissey, Manuel Toharia
Connecting (Supersymmetry) LHC Measurements with High Scale Theories
39 pages, 14 figures
Phys.Rev.D75:115018,2007
10.1103/PhysRevD.75.115018
MCTP-06-37, SU-4252-842
hep-ph
null
If supersymmetry is discovered at the LHC, the measured spectrum of superpartner masses and couplings will allow us to probe the origins of supersymmetry breaking. However, to connect the collider-scale Lagrangian soft parameters to the more fundamental theory from which they arise, it is usually necessary to evolve them to higher scales. The apparent unification of gauge couplings restricts the possible forms of new physics above the electroweak scale, and suggests that such an extrapolation is possible. Even so, this task is complicated if the low scale spectrum is not measured completely or precisely, or if there is new physics at heavy scales beyond the reach of collider experiments. In this work we study some of these obstacles to running up, and we investigate how to get around them. Our main conclusion is that even though such obstacles can make it very difficult to accurately determine the values of all the soft parameters at the high scale, there exist a number of special combinations of the soft parameters that can avoid these difficulties. We also present a systematic application of our techniques in an explicit example.
[ { "created": "Thu, 21 Dec 2006 19:18:58 GMT", "version": "v1" } ]
2008-11-26
[ [ "Kane", "Gordon L.", "" ], [ "Kumar", "Piyush", "" ], [ "Morrissey", "David E.", "" ], [ "Toharia", "Manuel", "" ] ]
If supersymmetry is discovered at the LHC, the measured spectrum of superpartner masses and couplings will allow us to probe the origins of supersymmetry breaking. However, to connect the collider-scale Lagrangian soft parameters to the more fundamental theory from which they arise, it is usually necessary to evolve them to higher scales. The apparent unification of gauge couplings restricts the possible forms of new physics above the electroweak scale, and suggests that such an extrapolation is possible. Even so, this task is complicated if the low scale spectrum is not measured completely or precisely, or if there is new physics at heavy scales beyond the reach of collider experiments. In this work we study some of these obstacles to running up, and we investigate how to get around them. Our main conclusion is that even though such obstacles can make it very difficult to accurately determine the values of all the soft parameters at the high scale, there exist a number of special combinations of the soft parameters that can avoid these difficulties. We also present a systematic application of our techniques in an explicit example.
hep-ph/9809560
Alan Kostelecky
Alan Kostelecky
Testing CPT with B Mesons
9 pages, talk published in the Proceedings of the Symposium `Twenty Beautiful Years of Bottom Physics,' IIT, June 29-July 2, 1997, editors R.A. Burnstein, D.M. Kaplan, H.A. Rubin (AIP, Woodbury, New York, 1998)
null
null
IUHET 370, August 1997
hep-ph
null
Apparent violations of CPT and Lorentz symmetry might arise in nature as a result of spontaneous symmetry breaking in a theory beyond the standard model. This talk summarizes a few relevant theoretical and experimental issues, with some emphasis on implications for CPT tests with neutral-B mesons.
[ { "created": "Mon, 28 Sep 1998 13:38:45 GMT", "version": "v1" } ]
2007-05-23
[ [ "Kostelecky", "Alan", "" ] ]
Apparent violations of CPT and Lorentz symmetry might arise in nature as a result of spontaneous symmetry breaking in a theory beyond the standard model. This talk summarizes a few relevant theoretical and experimental issues, with some emphasis on implications for CPT tests with neutral-B mesons.
2109.04895
Peter Milonni
Peter W. Milonni
Simplified derivation of the Kompaneets equation
null
null
10.1063/5.0063886
null
hep-ph physics.plasm-ph
http://creativecommons.org/licenses/by/4.0/
An isotropic electromagnetic field in a plasma of thermalized electrons undergoes changes in energy as a result of Compton scattering and an Einstein-Hopf drag force on the electrons, eventually approaching a Bose-Einstein photon distribution at the electron temperature. The rate of change of feld energy due to the combined effects of Compton scattering and the drag force is shown to be described by the Kompaneets equation for photon diffusion in frequency space. A similarity is noted between this approach and Einstein's derivation of the Planck spectrum based on the recoil of atoms as they absorb and emit radiation.
[ { "created": "Wed, 8 Sep 2021 17:11:47 GMT", "version": "v1" } ]
2021-10-04
[ [ "Milonni", "Peter W.", "" ] ]
An isotropic electromagnetic field in a plasma of thermalized electrons undergoes changes in energy as a result of Compton scattering and an Einstein-Hopf drag force on the electrons, eventually approaching a Bose-Einstein photon distribution at the electron temperature. The rate of change of feld energy due to the combined effects of Compton scattering and the drag force is shown to be described by the Kompaneets equation for photon diffusion in frequency space. A similarity is noted between this approach and Einstein's derivation of the Planck spectrum based on the recoil of atoms as they absorb and emit radiation.
hep-ph/0012189
M. Tentioukov
J. Fleischer, M. Tentyukov
A Feynman Diagram Analyser DIANA - Graphic Facilities
LaTeX2e, 3 pages, 4 eps-figures, uses aipproc.cls; Contribution to Proceeding of VII International Workshop on Advanced Computing and Analysis Techniques in Physics Research ACAT 2000 (Formerly AIHENP) October 16-20, 2000
null
10.1063/1.1405301
null
hep-ph
null
New developments concerning the extension of the recently introduced Feynman diagram analyser DIANA are presented.
[ { "created": "Fri, 15 Dec 2000 17:31:37 GMT", "version": "v1" } ]
2009-10-31
[ [ "Fleischer", "J.", "" ], [ "Tentyukov", "M.", "" ] ]
New developments concerning the extension of the recently introduced Feynman diagram analyser DIANA are presented.
hep-ph/0603196
George Rupp
M.D. Scadron, R. Delbourgo, and G. Rupp
Constituent Quark Masses and the Electroweak Standard Model
IOP LaTeX, 12 pages, 1 table; PACS nos. 12.15.-y, 12.40.Vv, 14.65.-q, 13.40.Em; accepted for publication in Journal of Physics G
J.Phys.G32:735-745,2006
10.1088/0954-3899/32/5/009
null
hep-ph
null
Constituent quark masses can be determined quite well from experimental data in several ways and one can obtain fairly accurate values for all six $m_q$. The strong quark-meson coupling $g=2\pi /\sqrt{3}$ arises from the quark-level linear $\sigma$ model, whereas $e$ and $\sin\theta_w$ arise from weak interactions when the heavy $M_W$ and $M_Z$ are regarded as resonances in analogy with the strong KSFR relation. The Higgs boson mass, tied to null expectation value of charged Higgs components, is found to be around 317 GeV. Finally, the experimental CPV phase angle $\delta$ and the three CKM angles $\Theta_c, \Theta_2, \Theta_3$ are successfully deduced from the 6 constituent quark masses following Fritzsch's approach.
[ { "created": "Thu, 23 Mar 2006 18:28:08 GMT", "version": "v1" } ]
2009-11-11
[ [ "Scadron", "M. D.", "" ], [ "Delbourgo", "R.", "" ], [ "Rupp", "G.", "" ] ]
Constituent quark masses can be determined quite well from experimental data in several ways and one can obtain fairly accurate values for all six $m_q$. The strong quark-meson coupling $g=2\pi /\sqrt{3}$ arises from the quark-level linear $\sigma$ model, whereas $e$ and $\sin\theta_w$ arise from weak interactions when the heavy $M_W$ and $M_Z$ are regarded as resonances in analogy with the strong KSFR relation. The Higgs boson mass, tied to null expectation value of charged Higgs components, is found to be around 317 GeV. Finally, the experimental CPV phase angle $\delta$ and the three CKM angles $\Theta_c, \Theta_2, \Theta_3$ are successfully deduced from the 6 constituent quark masses following Fritzsch's approach.
hep-ph/9904385
Maciej Skrzypek
M. Skrzypek and Z. Was (Inst. of Nucl. Phys., Cracow, Poland and CERN, Geneva, Switzerland)
How to Generate Four-Fermion Phase Space
16 pages
Comput.Phys.Commun. 125 (2000) 8-20
10.1016/S0010-4655(99)00457-9
CERN-TH/99-98
hep-ph
null
We present a scheme for integrating the matrix element of an arbitrary e^+e^-\to f_1f_2\bar f_3\bar f_4 process over the complete four-fermion phase space, or its any part, by means of the Monte Carlo technique. The presented algorithm has been successfully implemented in the KORALW Monte Carlo code.
[ { "created": "Mon, 19 Apr 1999 12:13:01 GMT", "version": "v1" } ]
2009-10-31
[ [ "Skrzypek", "M.", "", "Inst. of Nucl. Phys., Cracow, Poland and CERN,\n Geneva, Switzerland" ], [ "Was", "Z.", "", "Inst. of Nucl. Phys., Cracow, Poland and CERN,\n Geneva, Switzerland" ] ]
We present a scheme for integrating the matrix element of an arbitrary e^+e^-\to f_1f_2\bar f_3\bar f_4 process over the complete four-fermion phase space, or its any part, by means of the Monte Carlo technique. The presented algorithm has been successfully implemented in the KORALW Monte Carlo code.
1808.04396
Ted Rogers
J. O. Gonzalez-Hernandez, T. C. Rogers, N. Sato, and B. Wang
Challenges with Large Transverse Momentum in Semi-Inclusive Deeply Inelastic Scattering
11 pages, 7 figures. arXiv admin note: text overlap with arXiv:hep-ph/0411212 by other authors, version to appear in PRD
Phys. Rev. D 98, 114005 (2018)
10.1103/PhysRevD.98.114005
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We survey the current phenomenological status of semi-inclusive deep inelastic scattering at moderate hard scales and in the limit of very large transverse momentum. As the transverse momentum becomes comparable to or larger than the overall hard scale, the differential cross sections should be calculable with fixed order pQCD methods, while small transverse momentum (TMD factorization) approximations should eventually break down. We find large disagreement between HERMES and COMPASS data and fixed order calculations done with modern parton densities, even in regions of kinematics where such calculations should be expected to be very accurate. Possible interpretations are suggested.
[ { "created": "Mon, 13 Aug 2018 18:33:45 GMT", "version": "v1" }, { "created": "Wed, 12 Dec 2018 16:51:53 GMT", "version": "v2" } ]
2018-12-19
[ [ "Gonzalez-Hernandez", "J. O.", "" ], [ "Rogers", "T. C.", "" ], [ "Sato", "N.", "" ], [ "Wang", "B.", "" ] ]
We survey the current phenomenological status of semi-inclusive deep inelastic scattering at moderate hard scales and in the limit of very large transverse momentum. As the transverse momentum becomes comparable to or larger than the overall hard scale, the differential cross sections should be calculable with fixed order pQCD methods, while small transverse momentum (TMD factorization) approximations should eventually break down. We find large disagreement between HERMES and COMPASS data and fixed order calculations done with modern parton densities, even in regions of kinematics where such calculations should be expected to be very accurate. Possible interpretations are suggested.
hep-ph/9208256
null
W. Broniowski and T. D. Cohen
Response of nucleons to external probes in hedgehog models: I. Electromagnetic polarizabilities
27 pages, DOE/ER/40322-155, U. of MD PP \#92-193, (ReVTeX)
Phys.Rev.D47:299-312,1993
10.1103/PhysRevD.47.299
null
hep-ph
null
Electromagnetic polarizabilities of the nucleon are analyzed in a hedgehog model with quark and meson degrees of freedom.
[ { "created": "Thu, 27 Aug 1992 20:31:01 GMT", "version": "v1" } ]
2010-11-01
[ [ "Broniowski", "W.", "" ], [ "Cohen", "T. D.", "" ] ]
Electromagnetic polarizabilities of the nucleon are analyzed in a hedgehog model with quark and meson degrees of freedom.
hep-ph/0605330
J\"org Ruppert
Thorsten Renk, Jorg Ruppert
The rapidity structure of Mach cones and other large angle correlations in heavy-ion collisions
9 pages, 3 figures, version to appear in Phys. Lett. B
Phys.Lett.B646:19-23,2007
10.1016/j.physletb.2007.01.008
null
hep-ph
null
The pattern of angular correlations of hadrons with a (semi-)hard trigger hadron in heavy-ion collisions has attracted considerable interest. In particular, unexpected large angle structures on the away side (opposite to the trigger) have been found. Several explanations have been brought forward, among them Mach shockwaves and Cherenkov radiation. Most of these scenarios are characterized by radial symmetry around the parton axis, thus angular correlations also determine the rapidity dependence of the correlation. If the observed correlations are remnants of an away side parton after interaction with the medium created in the collision, pQCD allows to calculate the distribution $P(y)$ of the away side partons in rapidity. The measured correlation then arises as a folding of $P(y)$ and the rapidity structure of the correlation taking into account the detector acceptance. This places non-trivial and rather stringent constraints on the underlying scenario. We investigate these dependences and demonstrate that Mach shockwaves survive this folding procedure well whereas Cherenkov radiation scenarios face new challenges.
[ { "created": "Tue, 30 May 2006 11:50:13 GMT", "version": "v1" }, { "created": "Mon, 22 Jan 2007 18:00:29 GMT", "version": "v2" } ]
2008-11-26
[ [ "Renk", "Thorsten", "" ], [ "Ruppert", "Jorg", "" ] ]
The pattern of angular correlations of hadrons with a (semi-)hard trigger hadron in heavy-ion collisions has attracted considerable interest. In particular, unexpected large angle structures on the away side (opposite to the trigger) have been found. Several explanations have been brought forward, among them Mach shockwaves and Cherenkov radiation. Most of these scenarios are characterized by radial symmetry around the parton axis, thus angular correlations also determine the rapidity dependence of the correlation. If the observed correlations are remnants of an away side parton after interaction with the medium created in the collision, pQCD allows to calculate the distribution $P(y)$ of the away side partons in rapidity. The measured correlation then arises as a folding of $P(y)$ and the rapidity structure of the correlation taking into account the detector acceptance. This places non-trivial and rather stringent constraints on the underlying scenario. We investigate these dependences and demonstrate that Mach shockwaves survive this folding procedure well whereas Cherenkov radiation scenarios face new challenges.
hep-ph/9401256
null
C.E. Carlson and J.Milana
Systematics of Exclusive B-decays
32 pages
Phys.Rev.D49:5908-5920,1994
10.1103/PhysRevD.49.5908
U. of MD PP \#94-062 DOE/ER/40762-022 and WM-93-110
hep-ph
null
Systematic analysis of the high recoil decay channels of the B-meson, two body mesonic decay channels in particular. For decays involving D-mesons, all experimentally observed rates are in reasonable accord with our calculations. Noticeable corrections to heavy quark symmetry are found, appearing most prominently when comparing D and D* decay modes. Calculated branching ratios involving the CKM matrix element V_{ub} are all below experimental upper bounds, but not markedly so. Calculated decay rates into charmonium lie a bit on the low side. Where color-suppressed diagrams contribute, they are found to be also suppressed dynamically and explicit calculation shows that the color-suppressed diagrams are ignorable in B to D pi decays.
[ { "created": "Fri, 14 Jan 1994 15:39:00 GMT", "version": "v1" } ]
2010-11-01
[ [ "Carlson", "C. E.", "" ], [ "Milana", "J.", "" ] ]
Systematic analysis of the high recoil decay channels of the B-meson, two body mesonic decay channels in particular. For decays involving D-mesons, all experimentally observed rates are in reasonable accord with our calculations. Noticeable corrections to heavy quark symmetry are found, appearing most prominently when comparing D and D* decay modes. Calculated branching ratios involving the CKM matrix element V_{ub} are all below experimental upper bounds, but not markedly so. Calculated decay rates into charmonium lie a bit on the low side. Where color-suppressed diagrams contribute, they are found to be also suppressed dynamically and explicit calculation shows that the color-suppressed diagrams are ignorable in B to D pi decays.
hep-ph/9710478
Lee Kang Young
Kang Young Lee (Yonsei U.)
Implications of the recent CERN LEP data on nonuniversal interactions with the precision electroweak tests
17 pages (including figs), ReVTeX, 5 .eps figs are included, to appear in Phys. Rev. D
Phys.Rev. D57 (1998) 598-601
10.1103/PhysRevD.57.598
YUMS 97--17
hep-ph
null
We explore the nonuniversal interaction effects in terms of the precision variables epsilons with the recent LEP data reported by the Electroweak Working Group. The epsilon variables with the nonuniversal interactions are calculated and constrained by the experimental ellipses in the $\epsilon_1$--$\epsilon_b$, $\epsilon_2$--$\epsilon_b$, and $\epsilon_3$--$\epsilon_b$ planes. We find that the new data enables us to make a stringent test on the correction to $Z \to b \bar{b}$ vertex. The $\epsilon_b$ variable is sensitive to the $Z b \bar b$ couplings and thus plays a major role to give constraints on the nonuniversal interaction effects. Upon imposing the new data on $\epsilon_b$, we have the allowed range of the model parameter $\kappa_L = 0.0063 \pm 0.0030$ at 1-$\sigma$ level with $m_t = 175$ GeV. Along with the minimal contact term, we predict the new physics scale $\Lambda \sim$ 1.6 TeV. By combining the experimental results from all planes we obtain the allowed range of $\kappa_L$ : $0.003 < \kappa_L < 0.010$ at 95 % C.L..
[ { "created": "Mon, 27 Oct 1997 02:57:17 GMT", "version": "v1" } ]
2009-10-30
[ [ "Lee", "Kang Young", "", "Yonsei U." ] ]
We explore the nonuniversal interaction effects in terms of the precision variables epsilons with the recent LEP data reported by the Electroweak Working Group. The epsilon variables with the nonuniversal interactions are calculated and constrained by the experimental ellipses in the $\epsilon_1$--$\epsilon_b$, $\epsilon_2$--$\epsilon_b$, and $\epsilon_3$--$\epsilon_b$ planes. We find that the new data enables us to make a stringent test on the correction to $Z \to b \bar{b}$ vertex. The $\epsilon_b$ variable is sensitive to the $Z b \bar b$ couplings and thus plays a major role to give constraints on the nonuniversal interaction effects. Upon imposing the new data on $\epsilon_b$, we have the allowed range of the model parameter $\kappa_L = 0.0063 \pm 0.0030$ at 1-$\sigma$ level with $m_t = 175$ GeV. Along with the minimal contact term, we predict the new physics scale $\Lambda \sim$ 1.6 TeV. By combining the experimental results from all planes we obtain the allowed range of $\kappa_L$ : $0.003 < \kappa_L < 0.010$ at 95 % C.L..
hep-ph/0307245
T. Goldman
G. J. Stephenson, Jr.(1), T. Goldman (2), B. H. J. McKellar (3) and M. Garbutt (3) ((1) U. of New Mexico, (2) LANL, (3) U. of Melbourne)
3+2 neutrinos in a see-saw variation
17pp., 1 fig., revtex4; typo corrected in Table
null
null
LA-UR-03-5159
hep-ph
null
If the sterile neutrino mass matrix in an otherwise conventional see-saw model has a rank less than the number of flavors, it is possible to produce pseudo-Dirac neutrinos. For the rank 1 case, 3+2 scenarios devolve naturally, as we show by example. Additionally, we find that the lower rank see-saw suppresses some mass differences, so that small mass differences do not require that the individual masses of each neutrino must also be small.
[ { "created": "Fri, 18 Jul 2003 22:30:00 GMT", "version": "v1" }, { "created": "Mon, 28 Jul 2003 03:36:46 GMT", "version": "v2" } ]
2012-08-27
[ [ "Stephenson,", "G. J.", "Jr.", "U. of New Mexico" ], [ "Goldman", "T.", "", "LANL" ], [ "McKellar", "B. H. J.", "", "U. of Melbourne" ], [ "Garbutt", "M.", "", "U. of Melbourne" ] ]
If the sterile neutrino mass matrix in an otherwise conventional see-saw model has a rank less than the number of flavors, it is possible to produce pseudo-Dirac neutrinos. For the rank 1 case, 3+2 scenarios devolve naturally, as we show by example. Additionally, we find that the lower rank see-saw suppresses some mass differences, so that small mass differences do not require that the individual masses of each neutrino must also be small.
hep-ph/0111270
Leonard Gamberg
Leonard Gamberg and Gary R. Goldstein
The Chiral Odd Nucleon Tensor Charge
6 pages LaTeX with ws-p8-50x6-00.cls (included). To appear in the proceedings of the 6th workshop on non-perturbative QCD, Paris, June 2001
null
10.1142/9789812778352_0020
TUHEP-TH01-06
hep-ph
null
Exploiting the phenomenological symmetry of the $J^{PC}=1^{+-}$ light axial vector mesons and using pole dominance, we calculate the flavor contributions to the nucleon tensor charge.
[ { "created": "Wed, 21 Nov 2001 22:25:39 GMT", "version": "v1" } ]
2017-08-23
[ [ "Gamberg", "Leonard", "" ], [ "Goldstein", "Gary R.", "" ] ]
Exploiting the phenomenological symmetry of the $J^{PC}=1^{+-}$ light axial vector mesons and using pole dominance, we calculate the flavor contributions to the nucleon tensor charge.
hep-ph/0508298
Giovanni Salesi
E. Di Grezia, S. Esposito and G. Salesi
Baryon asymmetry in the Universe resulting from Lorentz violation
7 pages
Europhys.Lett. 74 (2006) 747-753
10.1209/epl/i2005-10573-4
null
hep-ph
null
We analyze the phenomenological consequences of a Lorentz violating energy-momentum dispersion relation in order to give a simple explanation for the baryon asymmetry in the Universe. By assuming very few hypotheses, we propose a straightforward mechanism for generating the observed matter-antimatter asymmetry which entails a Lorentz-breakdown energy scale of the order of the Greisen-Zatsepin-Kuzmin cut-off.
[ { "created": "Mon, 29 Aug 2005 23:42:17 GMT", "version": "v1" }, { "created": "Sun, 14 Jan 2007 09:14:54 GMT", "version": "v2" }, { "created": "Fri, 19 Jan 2007 19:55:41 GMT", "version": "v3" } ]
2009-11-11
[ [ "Di Grezia", "E.", "" ], [ "Esposito", "S.", "" ], [ "Salesi", "G.", "" ] ]
We analyze the phenomenological consequences of a Lorentz violating energy-momentum dispersion relation in order to give a simple explanation for the baryon asymmetry in the Universe. By assuming very few hypotheses, we propose a straightforward mechanism for generating the observed matter-antimatter asymmetry which entails a Lorentz-breakdown energy scale of the order of the Greisen-Zatsepin-Kuzmin cut-off.
hep-ph/9606376
David A. Kosower
David A. Kosower
Overview of Perturbative QCD
null
null
null
Saclay/SPhT-T96/051
hep-ph
null
Overview of the perturbative QCD session at Moriond '96: theoretical techniques and current issues, primarily as applied to jet physics at colliders.
[ { "created": "Wed, 19 Jun 1996 14:47:19 GMT", "version": "v1" } ]
2007-05-23
[ [ "Kosower", "David A.", "" ] ]
Overview of the perturbative QCD session at Moriond '96: theoretical techniques and current issues, primarily as applied to jet physics at colliders.
2301.02304
Radja Boughezal
Radja Boughezal, Daniel de Florian, Frank Petriello, Werner Vogelsang
Transverse spin asymmetries at the EIC as a probe of anomalous electric and magnetic dipole moments
12 pages, 8 figures
null
10.1103/PhysRevD.107.075028
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
We show that inclusive single-spin asymmetries (SSAs) with transversely polarized protons or electrons at a future electron ion collider (EIC) are sensitive to new physics contributions to electroweak dipole operators of electrons and quarks. We use the Standard Model Effective Field Theory (SMEFT) to parameterize possible heavy new physics contributions to these couplings. We show that new physics scales at or beyond the TeV-scale can be probed assuming realistic EIC run parameters, and that the transverse spin asymmetries are sensitive to different combinations of the dipole couplings than other measurements such as anomalous magnetic or electric dipole moments. We also study the physics potential of SSAs at a possible future upgrade of the EIC to collide muons and protons. Measurements at such an upgrade could probe the same SMEFT parameters that explain the current anomaly in the muon anomalous magnetic moment, and could also improve current bounds on the muon electric dipole moment.
[ { "created": "Thu, 5 Jan 2023 21:35:26 GMT", "version": "v1" } ]
2023-05-03
[ [ "Boughezal", "Radja", "" ], [ "de Florian", "Daniel", "" ], [ "Petriello", "Frank", "" ], [ "Vogelsang", "Werner", "" ] ]
We show that inclusive single-spin asymmetries (SSAs) with transversely polarized protons or electrons at a future electron ion collider (EIC) are sensitive to new physics contributions to electroweak dipole operators of electrons and quarks. We use the Standard Model Effective Field Theory (SMEFT) to parameterize possible heavy new physics contributions to these couplings. We show that new physics scales at or beyond the TeV-scale can be probed assuming realistic EIC run parameters, and that the transverse spin asymmetries are sensitive to different combinations of the dipole couplings than other measurements such as anomalous magnetic or electric dipole moments. We also study the physics potential of SSAs at a possible future upgrade of the EIC to collide muons and protons. Measurements at such an upgrade could probe the same SMEFT parameters that explain the current anomaly in the muon anomalous magnetic moment, and could also improve current bounds on the muon electric dipole moment.
0911.0811
Yogiro Hama
Yogiro Hama, Rone Peterson G. Andrade, Frederique Grassi and Wei-Liang Qian
Trying to understand the ridge effect in hydrodynamic model
5 pages, 8 figures, prepared for XXXIX International Symposium on Multiparticle Dynamics, Belarus, 4-9 September 2009 and also for V Workshop on Particle Correlations and Femtoscopy, CERN (Switzerland), 14-17 October 2009
Nonlin.Phenom.Complex Syst.12:466-470,2009
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In a recent paper, the hydrodynamic code NeXSPheRIO was used in conjunction with STAR analysis methods to study two-particle correlations as function of Delta_eta and Delta_phi. Both the ridge-like near-side and the double-hump away-side structures were obtained. However, the mechanism of ridge production was not clear. In order to understand it, we study a simple model with only one high-energy density peripheral tube in a smooth cylindrical back-ground, with longitudinal boost invariance. The results are rather surprising, but the model does produce the triple-ridge structure with one high ridge plus two lower ones placed symmetrically with respect to the former one. The shape of this structure is rather stable in a wide range of parameters.
[ { "created": "Wed, 4 Nov 2009 12:56:08 GMT", "version": "v1" } ]
2012-08-07
[ [ "Hama", "Yogiro", "" ], [ "Andrade", "Rone Peterson G.", "" ], [ "Grassi", "Frederique", "" ], [ "Qian", "Wei-Liang", "" ] ]
In a recent paper, the hydrodynamic code NeXSPheRIO was used in conjunction with STAR analysis methods to study two-particle correlations as function of Delta_eta and Delta_phi. Both the ridge-like near-side and the double-hump away-side structures were obtained. However, the mechanism of ridge production was not clear. In order to understand it, we study a simple model with only one high-energy density peripheral tube in a smooth cylindrical back-ground, with longitudinal boost invariance. The results are rather surprising, but the model does produce the triple-ridge structure with one high ridge plus two lower ones placed symmetrically with respect to the former one. The shape of this structure is rather stable in a wide range of parameters.
1412.7365
Chihiro Sasaki
Chihiro Sasaki, Krzysztof Redlich
Correlations between light and heavy flavors near the chiral crossover
6 pages, 4 figures; v2) references added, discussions expanded though the main statement unchanged
null
10.1103/PhysRevD.91.074021
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Thermal fluctuations and correlations between the light and heavy-light mesons are explored within a chiral effective theory implementing heavy quark symmetry. We show, that various heavy-light flavor correlations indicate a remnant of the chiral criticality in a narrow range of temperature where the chiral susceptibility exhibits a peak structure. The onset of the chiral crossover, in the heavy-light flavor correlations, is therefore independent from the light flavors. This indicates that the fluctuations carried by strange charmed mesons can also be used to identify the chiral crossover, which is dominated by the non-strange light quark dynamics.
[ { "created": "Tue, 23 Dec 2014 14:04:42 GMT", "version": "v1" }, { "created": "Sat, 7 Mar 2015 20:23:07 GMT", "version": "v2" } ]
2015-06-23
[ [ "Sasaki", "Chihiro", "" ], [ "Redlich", "Krzysztof", "" ] ]
Thermal fluctuations and correlations between the light and heavy-light mesons are explored within a chiral effective theory implementing heavy quark symmetry. We show, that various heavy-light flavor correlations indicate a remnant of the chiral criticality in a narrow range of temperature where the chiral susceptibility exhibits a peak structure. The onset of the chiral crossover, in the heavy-light flavor correlations, is therefore independent from the light flavors. This indicates that the fluctuations carried by strange charmed mesons can also be used to identify the chiral crossover, which is dominated by the non-strange light quark dynamics.
2205.07049
Elena Santopinto
H. Garcia-Tecocoatzi, A. Giachino, J. Li, A. Ramirez-Morales, E. Santopinto
Strong decay widths and mass spectra of charmed baryons
29 pages, 12 figures
null
10.1103/PhysRevD.107.034031
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The total decay widths of the charmed baryons are calculated by means of the $^3P_0$ model. Our calculations consider in the final states: the charmed baryon-(vector/pseudoscalar) meson pairs and the (octet/ decuplet) baryon-(pseudoscalar/vector) charmed meson pairs, within a constituent quark model. Furthermore, we calculate the masses of the charmed baryon ground states and their excitations up to the $D$-wave in a constituent quark model both in the three-quark and in the quark-diquark schemes, utilizing a Hamiltonian model based on a harmonic oscillator potential plus a mass splitting term that encodes the spin, \mbox{spin-orbit}, isospin, and flavor interactions. The parameters of the Hamiltonian model are fitted to the experimental data of the charmed baryon masses and decay widths. As the experimental uncertainties of the data affect the fitted model parameters, we have thoroughly propagated these uncertainties into our predicted charmed baryon masses and decay widths via a Monte Carlo bootstrap approach, which is often absent in other theoretical studies on this subject. Our quantum number assignments and predictions of the masses and strong partial decay widths are in reasonable agreement with the available data. Thus, our results show the ability to guide future measurements in LHCb, Belle and Belle II experiments. Finally, the appendices provide some details of our calculations, in which we include the flavor coupling coefficients, which are useful for further theoretical investigations.
[ { "created": "Sat, 14 May 2022 12:35:30 GMT", "version": "v1" }, { "created": "Mon, 4 Jul 2022 06:29:30 GMT", "version": "v2" }, { "created": "Tue, 21 Feb 2023 16:06:23 GMT", "version": "v3" } ]
2023-03-08
[ [ "Garcia-Tecocoatzi", "H.", "" ], [ "Giachino", "A.", "" ], [ "Li", "J.", "" ], [ "Ramirez-Morales", "A.", "" ], [ "Santopinto", "E.", "" ] ]
The total decay widths of the charmed baryons are calculated by means of the $^3P_0$ model. Our calculations consider in the final states: the charmed baryon-(vector/pseudoscalar) meson pairs and the (octet/ decuplet) baryon-(pseudoscalar/vector) charmed meson pairs, within a constituent quark model. Furthermore, we calculate the masses of the charmed baryon ground states and their excitations up to the $D$-wave in a constituent quark model both in the three-quark and in the quark-diquark schemes, utilizing a Hamiltonian model based on a harmonic oscillator potential plus a mass splitting term that encodes the spin, \mbox{spin-orbit}, isospin, and flavor interactions. The parameters of the Hamiltonian model are fitted to the experimental data of the charmed baryon masses and decay widths. As the experimental uncertainties of the data affect the fitted model parameters, we have thoroughly propagated these uncertainties into our predicted charmed baryon masses and decay widths via a Monte Carlo bootstrap approach, which is often absent in other theoretical studies on this subject. Our quantum number assignments and predictions of the masses and strong partial decay widths are in reasonable agreement with the available data. Thus, our results show the ability to guide future measurements in LHCb, Belle and Belle II experiments. Finally, the appendices provide some details of our calculations, in which we include the flavor coupling coefficients, which are useful for further theoretical investigations.
hep-ph/0307221
Firooz Arash
Firooz Arash
Meson Structure Functions in Valon Model
13 pages with 7 figures included, The manuscript is revised, figures are added and some errors are corrected. Accepted for publication in Physical Review D
Phys.Rev. D69 (2004) 054024
10.1103/PhysRevD.69.054024
null
hep-ph hep-ex nucl-th
null
Parton distributions in a {\it{valon}} in the next-to-leading order is used to determine the patron distributions in pion and kaon. The validity of the valon model is tested and shown that the partonic content of the valon is universal and independent of the valon type. We have evaluated the valon distribution in pion and kaon, and in particular it is shown that the results are in good agreement with the experimental data on pion structure in a wide range of $x=[10^{-4},1]$
[ { "created": "Thu, 17 Jul 2003 11:55:43 GMT", "version": "v1" }, { "created": "Tue, 13 Jan 2004 10:45:34 GMT", "version": "v2" } ]
2009-11-10
[ [ "Arash", "Firooz", "" ] ]
Parton distributions in a {\it{valon}} in the next-to-leading order is used to determine the patron distributions in pion and kaon. The validity of the valon model is tested and shown that the partonic content of the valon is universal and independent of the valon type. We have evaluated the valon distribution in pion and kaon, and in particular it is shown that the results are in good agreement with the experimental data on pion structure in a wide range of $x=[10^{-4},1]$
0911.1323
Goran Senjanovic
Borut Bajc, Miha Nemevsek and Goran Senjanovic
Probing leptonic CP phases in LFV processes
15 pages, 2 figures
Phys.Lett.B684:231-235,2010
10.1016/j.physletb.2010.01.025
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study a CP and T violating triple (spin) correlation in the muon to electron conversion in nuclei in the context of the seesaw mechanism. After concluding that the results are negative for all three seesaw types, we turn to the left-right symmetric theories as the original source of seesaw. We find that in general this correlation is of order one which offers a hope of observing CP violation in lepton flavor violating processes for a L-R scale below around 10-30 TeV. We discuss the conditions that could render to (unlikely) conspiracies as to suppress the CP violating effects.
[ { "created": "Fri, 6 Nov 2009 18:26:17 GMT", "version": "v1" } ]
2010-03-03
[ [ "Bajc", "Borut", "" ], [ "Nemevsek", "Miha", "" ], [ "Senjanovic", "Goran", "" ] ]
We study a CP and T violating triple (spin) correlation in the muon to electron conversion in nuclei in the context of the seesaw mechanism. After concluding that the results are negative for all three seesaw types, we turn to the left-right symmetric theories as the original source of seesaw. We find that in general this correlation is of order one which offers a hope of observing CP violation in lepton flavor violating processes for a L-R scale below around 10-30 TeV. We discuss the conditions that could render to (unlikely) conspiracies as to suppress the CP violating effects.
1307.7485
Xin Yu
Xin Yu, Zhi-Tian Zou, Cai-Dian Lu
Time-dependent CP-violations of B(Bs) decays in the perturbative QCD approach
14 pages, 2 figures, 2 tables
null
10.1103/PhysRevD.88.054018
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the decay modes of B_{s}^{0}(\bar{B}_{s}^{0})-->D_{s}^{\pm} K^{\mp}, B_{s}^{0}(\bar{B}_{s}^{0})-->D^{\pm} \pi^{\mp} and B^{0}(\bar{B}^{0})-->D^{\pm} \pi^{\mp} in the perterbative QCD approach based on k_T factorization, including the branching ratios and CP violation parameters which provide a clear way to extract the Cabibbo-Kobayashi-Maskawa angle \gamma. Our results of branching ratios of B_{s}^{0}(\bar{B}_{s}^{0})-->D_{s}^{\pm} K^{\mp} and B^{0}(\bar{B}^{0})--> D^{\pm} \pi^{\mp} and the CP asymmetry of B^{0}(\bar{B}^{0})--> D^{\pm} \pi^{\mp} agree well with the experimental data. We also give the predictions of the other observables, which provide some guidance for experiments in the future, especially for LHCb experiment.
[ { "created": "Mon, 29 Jul 2013 07:19:53 GMT", "version": "v1" } ]
2013-09-25
[ [ "Yu", "Xin", "" ], [ "Zou", "Zhi-Tian", "" ], [ "Lu", "Cai-Dian", "" ] ]
We study the decay modes of B_{s}^{0}(\bar{B}_{s}^{0})-->D_{s}^{\pm} K^{\mp}, B_{s}^{0}(\bar{B}_{s}^{0})-->D^{\pm} \pi^{\mp} and B^{0}(\bar{B}^{0})-->D^{\pm} \pi^{\mp} in the perterbative QCD approach based on k_T factorization, including the branching ratios and CP violation parameters which provide a clear way to extract the Cabibbo-Kobayashi-Maskawa angle \gamma. Our results of branching ratios of B_{s}^{0}(\bar{B}_{s}^{0})-->D_{s}^{\pm} K^{\mp} and B^{0}(\bar{B}^{0})--> D^{\pm} \pi^{\mp} and the CP asymmetry of B^{0}(\bar{B}^{0})--> D^{\pm} \pi^{\mp} agree well with the experimental data. We also give the predictions of the other observables, which provide some guidance for experiments in the future, especially for LHCb experiment.
1206.0544
Peter Schichtel
Peter Schichtel, Christoph Englert, Erik Gerwick, Tilman Plehn, Steffen Schumann
From Jet Counting to Jet Vetoes
4 pages, 4 figures, to appear in the proceedings of XX International Workshop on Deep-Inelastic Scattering and Related Subjects, 26th-30th March 2012, University of Bonn
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The properties of multi-jet events impact many LHC analysis. The exclusive number of jets at hadron colliders can be described in terms of two simple patterns: staircase scaling and Poisson scaling. In photon plus jets production we can interpolate between the two patterns using simple kinematic cuts. The associated theoretical errors are well under control. Understanding such exclusive jet multiplicities significantly impacts Higgs searches and searches for supersymmetry at the LHC.
[ { "created": "Mon, 4 Jun 2012 08:30:34 GMT", "version": "v1" } ]
2012-06-05
[ [ "Schichtel", "Peter", "" ], [ "Englert", "Christoph", "" ], [ "Gerwick", "Erik", "" ], [ "Plehn", "Tilman", "" ], [ "Schumann", "Steffen", "" ] ]
The properties of multi-jet events impact many LHC analysis. The exclusive number of jets at hadron colliders can be described in terms of two simple patterns: staircase scaling and Poisson scaling. In photon plus jets production we can interpolate between the two patterns using simple kinematic cuts. The associated theoretical errors are well under control. Understanding such exclusive jet multiplicities significantly impacts Higgs searches and searches for supersymmetry at the LHC.
hep-ph/9808272
Xing Zhi-Zhong
Harald Fritzsch, Zhi-zhong Xing
Large Leptonic Flavor Mixing and the Mass Spectrum of Leptons
Latex 10 pages
Phys.Lett. B440 (1998) 313-318
10.1016/S0370-2693(98)01106-X
LMU-98-08
hep-ph hep-ex
null
Implications of a simple model for the mass generation of leptons are studied, in particular for the upcoming long-baseline neutrino experiments. The flavor mixing angles are large (nearly maximal). The probability for the long-baseline \nu_\mu \leftrightarrow \nu_e oscillation is predicted to be about 1%.
[ { "created": "Mon, 10 Aug 1998 09:36:22 GMT", "version": "v1" }, { "created": "Tue, 3 Nov 1998 14:13:33 GMT", "version": "v2" } ]
2009-10-31
[ [ "Fritzsch", "Harald", "" ], [ "Xing", "Zhi-zhong", "" ] ]
Implications of a simple model for the mass generation of leptons are studied, in particular for the upcoming long-baseline neutrino experiments. The flavor mixing angles are large (nearly maximal). The probability for the long-baseline \nu_\mu \leftrightarrow \nu_e oscillation is predicted to be about 1%.
2012.13553
Rene Poncelet
Herschel A. Chawdhry, Michal Czakon, Alexander Mitov, Rene Poncelet
Two-loop leading-color helicity amplitudes for three-photon production at the LHC
19 pages, 2 figures, published version
null
10.1007/JHEP06(2021)150
Cavendish-HEP-20/15, OUTP-20-16P, P3H-20-084, TTK-20-50
hep-ph hep-th
http://creativecommons.org/licenses/by/4.0/
We calculate all planar contributions to the two-loop massless helicity amplitudes for the process $q\bar q\to \gamma\gamma\gamma$. The results are presented in fully analytic form in terms of the functional basis proposed recently by Chicherin and Sotnikov. With this publication we provide the two-loop contributions already used by us in the NNLO QCD calculation of the LHC process $pp\to \gamma\gamma\gamma$ [Chawdhry et al. (2019)]. Our results agree with a recent calculation of the same amplitude [Abreu et al. (2020)] which was performed using different techniques. We combine several modern computational techniques, notably, analytic solutions for the IBP identities, finite-field reconstruction techniques as well as the recent approach [Chen (2019)] for efficiently projecting helicity amplitudes. Our framework appears well-suited for the calculation of two-loop multileg amplitudes for which complete sets of master integrals exist.
[ { "created": "Fri, 25 Dec 2020 10:23:30 GMT", "version": "v1" }, { "created": "Tue, 24 Aug 2021 08:01:30 GMT", "version": "v2" } ]
2021-08-25
[ [ "Chawdhry", "Herschel A.", "" ], [ "Czakon", "Michal", "" ], [ "Mitov", "Alexander", "" ], [ "Poncelet", "Rene", "" ] ]
We calculate all planar contributions to the two-loop massless helicity amplitudes for the process $q\bar q\to \gamma\gamma\gamma$. The results are presented in fully analytic form in terms of the functional basis proposed recently by Chicherin and Sotnikov. With this publication we provide the two-loop contributions already used by us in the NNLO QCD calculation of the LHC process $pp\to \gamma\gamma\gamma$ [Chawdhry et al. (2019)]. Our results agree with a recent calculation of the same amplitude [Abreu et al. (2020)] which was performed using different techniques. We combine several modern computational techniques, notably, analytic solutions for the IBP identities, finite-field reconstruction techniques as well as the recent approach [Chen (2019)] for efficiently projecting helicity amplitudes. Our framework appears well-suited for the calculation of two-loop multileg amplitudes for which complete sets of master integrals exist.
hep-ph/0703110
Yu Nakayama
M. Ibe, Y. Nakayama and T.T. Yanagida
Conformal Gauge Mediation
17 pages
null
10.1016/j.physletb.2007.04.002
SLAC-PUB-12388, UT-07-10
hep-ph
null
We propose a one-parameter theory for gauge mediation of supersymmetry (SUSY) breaking. The spectrum of SUSY particles such as squarks and sleptons in the SUSY standard-model and the dynamics of SUSY-breaking sector are, in principle, determined only by one parameter in the theory, that is, the mass of messengers. Above the messenger threshold all gauge coupling and Yukawa coupling constants in the SUSY-breaking sector are on the infrared fixed point. We find that the present theory may predict a split spectrum of the standard-model SUSY particles, m_{gaugino} < m_{sfermion}, where m_{gaugino} and m_{sfermion} are SUSY-breaking masses for gauginos and squarks/sleptons, respectively.
[ { "created": "Sat, 10 Mar 2007 06:01:19 GMT", "version": "v1" } ]
2009-11-13
[ [ "Ibe", "M.", "" ], [ "Nakayama", "Y.", "" ], [ "Yanagida", "T. T.", "" ] ]
We propose a one-parameter theory for gauge mediation of supersymmetry (SUSY) breaking. The spectrum of SUSY particles such as squarks and sleptons in the SUSY standard-model and the dynamics of SUSY-breaking sector are, in principle, determined only by one parameter in the theory, that is, the mass of messengers. Above the messenger threshold all gauge coupling and Yukawa coupling constants in the SUSY-breaking sector are on the infrared fixed point. We find that the present theory may predict a split spectrum of the standard-model SUSY particles, m_{gaugino} < m_{sfermion}, where m_{gaugino} and m_{sfermion} are SUSY-breaking masses for gauginos and squarks/sleptons, respectively.
hep-ph/9904248
Lisi Eligio
G.L. Fogli, E. Lisi, A. Marrone, G. Scioscia (Bari U. and INFN, Bari)
Testing violations of special and general relativity through the energy dependence of nu_mu<--->nu_tau oscillations in the Super-Kamiokande atmospheric neutrino experiment
13 pages (RevTeX) + 6 figures (PostScript, color). Requires epsfig.sty
Phys.Rev.D60:053006,1999
10.1103/PhysRevD.60.053006
BARI-TH/335-99
hep-ph astro-ph gr-qc
null
The atmospheric neutrino data collected by the Super-Kamiokande experiment span about four decades in neutrino energy E, and are thus appropriate to probe the energy dependence of the oscillation wavelength \lambda associated to nu_mu<--->nu_tau flavor transitions, when these are assumed to explain the data. Such dependence takes the form \lambda^{-1}\propto E^n in a wide class of theoretical models, including ``standard'' oscillations due to neutrino mass and mixing (n=-1), energy-independent oscillations (n=0), and violations of the equivalence principle or of Lorentz invariance (n=1). We study first how the theoretical zenith distributions of sub-GeV, multi-GeV, and upward-going muon events change for different integer values of n. Then we perform a detailed analysis of the Super-Kamiokande data by treating the energy exponent n as a free parameter, with unconstrained scale factors for both the amplitude and the phase of nu_mu<--->nu_tau oscillations. We find a best-fit range n=-0.9 \pm 0.4 at 90% C.L., which confirms the standard scenario (n=-1) as the dominant oscillation mechanism, and strongly constrains possible concurrent exotic processes (n \neq -1). In particular, we work out the interesting case of leading standard oscillations plus subleading terms induced by violations of special or general relativity principles, and obtain extremely stringent upper bounds on the amplitude of such violations in the (nu_mu,nu_tau) sector.
[ { "created": "Tue, 6 Apr 1999 16:26:48 GMT", "version": "v1" } ]
2009-10-07
[ [ "Fogli", "G. L.", "", "Bari U. and INFN, Bari" ], [ "Lisi", "E.", "", "Bari U. and INFN, Bari" ], [ "Marrone", "A.", "", "Bari U. and INFN, Bari" ], [ "Scioscia", "G.", "", "Bari U. and INFN, Bari" ] ]
The atmospheric neutrino data collected by the Super-Kamiokande experiment span about four decades in neutrino energy E, and are thus appropriate to probe the energy dependence of the oscillation wavelength \lambda associated to nu_mu<--->nu_tau flavor transitions, when these are assumed to explain the data. Such dependence takes the form \lambda^{-1}\propto E^n in a wide class of theoretical models, including ``standard'' oscillations due to neutrino mass and mixing (n=-1), energy-independent oscillations (n=0), and violations of the equivalence principle or of Lorentz invariance (n=1). We study first how the theoretical zenith distributions of sub-GeV, multi-GeV, and upward-going muon events change for different integer values of n. Then we perform a detailed analysis of the Super-Kamiokande data by treating the energy exponent n as a free parameter, with unconstrained scale factors for both the amplitude and the phase of nu_mu<--->nu_tau oscillations. We find a best-fit range n=-0.9 \pm 0.4 at 90% C.L., which confirms the standard scenario (n=-1) as the dominant oscillation mechanism, and strongly constrains possible concurrent exotic processes (n \neq -1). In particular, we work out the interesting case of leading standard oscillations plus subleading terms induced by violations of special or general relativity principles, and obtain extremely stringent upper bounds on the amplitude of such violations in the (nu_mu,nu_tau) sector.
hep-ph/0406172
Kuraev Eduard
A.N. Ilyichev, E.A. Kuraev, V. Bytev, Yu. P. Peresun'ko
Compton and double Compton scattering processes at colliding electron-photon beams
null
J.Exp.Theor.Phys. 100 (2005) 31-38; Zh.Eksp.Teor.Fiz. 100 (2005) 37-44
10.1134/1.1866196
null
hep-ph
null
Radiative corrections (RC) to the Compton scattering cross section are calculated in the leading and next-to leading logarithmic approximation to the case of colliding high energy photon-electron beams. RC to the double Compton scattering cross section in the same experimental set-up are calculated in the leading logarithmic approximation. We consider the case when no pairs are created in the final state. We show that the differential cross section can be written in the form of the Drell-Yan process cross-section. Numerical values of the $K$-factor and the leading order distribution on the scattered electron energy fraction and scattering angle are presented.
[ { "created": "Wed, 16 Jun 2004 05:24:16 GMT", "version": "v1" }, { "created": "Fri, 21 Jan 2005 09:00:56 GMT", "version": "v2" } ]
2009-11-10
[ [ "Ilyichev", "A. N.", "" ], [ "Kuraev", "E. A.", "" ], [ "Bytev", "V.", "" ], [ "Peresun'ko", "Yu. P.", "" ] ]
Radiative corrections (RC) to the Compton scattering cross section are calculated in the leading and next-to leading logarithmic approximation to the case of colliding high energy photon-electron beams. RC to the double Compton scattering cross section in the same experimental set-up are calculated in the leading logarithmic approximation. We consider the case when no pairs are created in the final state. We show that the differential cross section can be written in the form of the Drell-Yan process cross-section. Numerical values of the $K$-factor and the leading order distribution on the scattered electron energy fraction and scattering angle are presented.
2107.10899
Thomas A. Trainor
Thomas A. Trainor
Statistical evaluation of fitted models applied to $\bf p_t$ spectrum data from 5 TeV and 13 TeV $\bf p$-$\bf p$ collisions at the large hadron collider
17 pages, 15 figures
null
null
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
In a recent analysis of high-statistics $p_t$ spectra from 5 and 13 TeV $p$-$p$ collisions a two-component (soft+hard) model (TCM) of hadron production near midrapidity, based on fixed model functions independent of collision multiplicity $n_{ch}$ or event selection criteria, was employed as a reference to determine data biases induced by the selection criteria. As in previous studies the fixed TCM accurately isolated jet-related and nonjet contributions to spectra. It was observed that two selection criteria (V0M and SPD), based on different pseudorapidity $\eta$ acceptances, bias the spectrum hard component (jet fragment distribution) in different but complementary ways whereas the soft component is not significantly biased. In the present study TCM model functions are adjusted (i.e. fitted) to accommodate data. The effect of selection bias is then represented by smooth evolution of model parameters with $n_{ch}$. To evaluate the quality of model fits, Z-scores (data-model differences divided by statistical uncertainties) are evaluated and compared with data/model ratios that are often used for such comparisons. Based on Z-scores the variable TCM is compared with two other frequently-invoked models: the Tsallis model and the blast-wave model as they have been recently applied to the same spectrum data. The results are relevant to recent claims that collectivity (various flow manifestations) as a possible manifestation of QGP formation is observed in small systems. Data systematics suggest that these $p$-$p$ $p_t$ spectra are consistent with conventional QCD.
[ { "created": "Thu, 22 Jul 2021 19:48:36 GMT", "version": "v1" } ]
2021-07-26
[ [ "Trainor", "Thomas A.", "" ] ]
In a recent analysis of high-statistics $p_t$ spectra from 5 and 13 TeV $p$-$p$ collisions a two-component (soft+hard) model (TCM) of hadron production near midrapidity, based on fixed model functions independent of collision multiplicity $n_{ch}$ or event selection criteria, was employed as a reference to determine data biases induced by the selection criteria. As in previous studies the fixed TCM accurately isolated jet-related and nonjet contributions to spectra. It was observed that two selection criteria (V0M and SPD), based on different pseudorapidity $\eta$ acceptances, bias the spectrum hard component (jet fragment distribution) in different but complementary ways whereas the soft component is not significantly biased. In the present study TCM model functions are adjusted (i.e. fitted) to accommodate data. The effect of selection bias is then represented by smooth evolution of model parameters with $n_{ch}$. To evaluate the quality of model fits, Z-scores (data-model differences divided by statistical uncertainties) are evaluated and compared with data/model ratios that are often used for such comparisons. Based on Z-scores the variable TCM is compared with two other frequently-invoked models: the Tsallis model and the blast-wave model as they have been recently applied to the same spectrum data. The results are relevant to recent claims that collectivity (various flow manifestations) as a possible manifestation of QGP formation is observed in small systems. Data systematics suggest that these $p$-$p$ $p_t$ spectra are consistent with conventional QCD.
1801.04946
Stefano Gariazzo
S. Gariazzo, M. Archidiacono, P.F. de Salas, O. Mena, C.A. Ternes, and M. T\'ortola
Neutrino masses and their ordering: Global Data, Priors and Models
21 pages, 5 figures, 6 tables; Replaced to match version accepted for publication
null
10.1088/1475-7516/2018/03/011
null
hep-ph astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a Bayesian analysis of the combination of current neutrino oscillation, neutrinoless double beta decay and CMB observations. Our major goal is to carefully investigate the possibility to single out one neutrino mass ordering, Normal Ordering or Inverted Ordering, with current data. Two possible parametrizations (three neutrino masses versus the lightest neutrino mass plus the two oscillation mass splittings) and priors (linear versus logarithmic) are examined. We find that the preference for NO is only driven by neutrino oscillation data. Moreover, the values of the Bayes factor indicate that the evidence for NO is strong only when the scan is performed over the three neutrino masses with logarithmic priors; for every other combination of parameterization and prior, the preference for NO is only weak. As a by-product of our Bayesian analyses, we are able to a) compare the Bayesian bounds on the neutrino mixing parameters to those obtained by means of frequentist approaches, finding a very good agreement; b) determine that the lightest neutrino mass plus the two mass splittings parametrization, motivated by the physical observables, is strongly preferred over the three neutrino mass eigenstates scan and c) find that there is a weak-to-moderate preference for logarithmic priors. These results establish the optimal strategy to successfully explore the neutrino parameter space, based on the use of the oscillation mass splittings and a logarithmic prior on the lightest neutrino mass. We also show that the limits on the total neutrino mass $\sum m_\nu$ can change dramatically when moving from one prior to the other. These results have profound implications for future studies on the neutrino mass ordering, as they crucially state the need for self-consistent analyses which explore the best parametrization and priors, without combining results that involve different assumptions.
[ { "created": "Mon, 15 Jan 2018 19:01:06 GMT", "version": "v1" }, { "created": "Sun, 25 Feb 2018 16:29:33 GMT", "version": "v2" } ]
2018-03-21
[ [ "Gariazzo", "S.", "" ], [ "Archidiacono", "M.", "" ], [ "de Salas", "P. F.", "" ], [ "Mena", "O.", "" ], [ "Ternes", "C. A.", "" ], [ "Tórtola", "M.", "" ] ]
We present a Bayesian analysis of the combination of current neutrino oscillation, neutrinoless double beta decay and CMB observations. Our major goal is to carefully investigate the possibility to single out one neutrino mass ordering, Normal Ordering or Inverted Ordering, with current data. Two possible parametrizations (three neutrino masses versus the lightest neutrino mass plus the two oscillation mass splittings) and priors (linear versus logarithmic) are examined. We find that the preference for NO is only driven by neutrino oscillation data. Moreover, the values of the Bayes factor indicate that the evidence for NO is strong only when the scan is performed over the three neutrino masses with logarithmic priors; for every other combination of parameterization and prior, the preference for NO is only weak. As a by-product of our Bayesian analyses, we are able to a) compare the Bayesian bounds on the neutrino mixing parameters to those obtained by means of frequentist approaches, finding a very good agreement; b) determine that the lightest neutrino mass plus the two mass splittings parametrization, motivated by the physical observables, is strongly preferred over the three neutrino mass eigenstates scan and c) find that there is a weak-to-moderate preference for logarithmic priors. These results establish the optimal strategy to successfully explore the neutrino parameter space, based on the use of the oscillation mass splittings and a logarithmic prior on the lightest neutrino mass. We also show that the limits on the total neutrino mass $\sum m_\nu$ can change dramatically when moving from one prior to the other. These results have profound implications for future studies on the neutrino mass ordering, as they crucially state the need for self-consistent analyses which explore the best parametrization and priors, without combining results that involve different assumptions.
1311.0283
Nikolaos Kidonakis
Nikolaos Kidonakis
Top Quark Production
30 pages, 25 figures, 4 tables; based on three invited lectures at the Physics of Heavy Quarks and Hadrons (HQ2013) Summer School, Dubna, Russia, July 15-28, 2013
null
null
KSU-HEP-110113
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
I discuss top quark production in hadronic collisions. I present the soft-gluon resummation formalism and its derivation from factorization and renormalization-group evolution, and two-loop calculations of soft anomalous dimensions in the eikonal approximation. I discuss the contributions of next-to-next-to-leading order (NNLO) soft-gluon corrections to the total cross sections and top-quark transverse momentum and rapidity distributions for top-antitop pair production, and for single-top production in the $t$ and $s$ channels and in association with a $W$ boson or a charged Higgs boson.
[ { "created": "Fri, 1 Nov 2013 20:00:01 GMT", "version": "v1" } ]
2013-11-05
[ [ "Kidonakis", "Nikolaos", "" ] ]
I discuss top quark production in hadronic collisions. I present the soft-gluon resummation formalism and its derivation from factorization and renormalization-group evolution, and two-loop calculations of soft anomalous dimensions in the eikonal approximation. I discuss the contributions of next-to-next-to-leading order (NNLO) soft-gluon corrections to the total cross sections and top-quark transverse momentum and rapidity distributions for top-antitop pair production, and for single-top production in the $t$ and $s$ channels and in association with a $W$ boson or a charged Higgs boson.
1008.4283
Joseph Boudreau
F. Azfar, J. Boudreau, N. Bousson, J.P. Fern\'andez, K. Gibson, G. Giurgiu, G. G\'omez-Ceballos, T. Kuhr, M. Kreps, C. Liu, P. Maksimovic, J. Morlock, L. Oakes, M. Paulini, E. Pueschel, A. Schmidt
Formulae for the Analysis of the Flavor-Tagged Decay B^0_s --> Jpsi phi
19 pages, no figures. Revised for JHEP
JHEP 1011:158,2010
10.1007/JHEP11(2010)158
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Differential rates in the decay B^0_s --> Jpsi phi, with phi --> K^+K^- and Jpsi --> mu^+ mu^- are sensitive to the CP-violation phase beta_s, predicted to be very small in the standard model. The analysis of B^0_s --> Jpsi phi decays is also suitable for measuring the B^0_s lifetime, the decay width difference DeltaGamma_s between the B^0_s mass eigenstates, and the B^0_s oscillation frequency Delta m even if appreciable CP violation does not occur. In this paper we present normalized probability densities useful in maximum likelihood fits, extended to allow for S-wave contributions on one hand and for the effects of direct CP violation on the other. Our treatment of the S-wave contributions includes the strong variation of the S-wave/P-wave amplitude ratio with m(K^+K^-) across the phi resonance, which was not considered in previous work. We include a scheme for re-normalizing the probability densities after detector sculpting of the angular distributions of the final state particles, and conclude with an examination of the symmetries of the rate formulae, with and without an S-wave contribution. All results are obtained with the use of a new compact formalism describing the differential decay rate of B^0_s mesons into Jpsi phi final states.
[ { "created": "Wed, 25 Aug 2010 14:07:40 GMT", "version": "v1" }, { "created": "Mon, 29 Nov 2010 17:15:08 GMT", "version": "v2" } ]
2010-12-09
[ [ "Azfar", "F.", "" ], [ "Boudreau", "J.", "" ], [ "Bousson", "N.", "" ], [ "Fernández", "J. P.", "" ], [ "Gibson", "K.", "" ], [ "Giurgiu", "G.", "" ], [ "Gómez-Ceballos", "G.", "" ], [ "Kuhr", "T.", "" ], [ "Kreps", "M.", "" ], [ "Liu", "C.", "" ], [ "Maksimovic", "P.", "" ], [ "Morlock", "J.", "" ], [ "Oakes", "L.", "" ], [ "Paulini", "M.", "" ], [ "Pueschel", "E.", "" ], [ "Schmidt", "A.", "" ] ]
Differential rates in the decay B^0_s --> Jpsi phi, with phi --> K^+K^- and Jpsi --> mu^+ mu^- are sensitive to the CP-violation phase beta_s, predicted to be very small in the standard model. The analysis of B^0_s --> Jpsi phi decays is also suitable for measuring the B^0_s lifetime, the decay width difference DeltaGamma_s between the B^0_s mass eigenstates, and the B^0_s oscillation frequency Delta m even if appreciable CP violation does not occur. In this paper we present normalized probability densities useful in maximum likelihood fits, extended to allow for S-wave contributions on one hand and for the effects of direct CP violation on the other. Our treatment of the S-wave contributions includes the strong variation of the S-wave/P-wave amplitude ratio with m(K^+K^-) across the phi resonance, which was not considered in previous work. We include a scheme for re-normalizing the probability densities after detector sculpting of the angular distributions of the final state particles, and conclude with an examination of the symmetries of the rate formulae, with and without an S-wave contribution. All results are obtained with the use of a new compact formalism describing the differential decay rate of B^0_s mesons into Jpsi phi final states.