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1401.0151
Zhenjun Xiao
Zhen-Jun Xiao and Xin Liu
The two-body hadronic decays of $B_c$ meson in the perturbative QCD approach: A short review
19 pages, 2 figures, 3 tables; Some references are updated. Final version being published in Chinese Science Bulletin
Chin.Sci.Bull. 59 (2014) 3748-3759
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Along with the running of Large Hadron Collider (LHC) located at CERN in November 2009, a large number of data samples of $B_c$ meson have been collected and some hadronic $B_c$ decay modes have been measured by the LHC experiments. In view of the special and important roles of $B_c$ meson decays playing in the heavy flavor sector, we here give a short review on the status of two body hadronic decays $B_c \to M_1 M_2$ at both experimental and theoretical aspects. For the theoretical progresses, specifically, we will show lots of theoretical studies on two body hadronic $B_c$ decays involving pseudoscalar, vector, scalar, axial-vector, even tensor meson(s) in the final states by employing the perturbative QCD (pQCD) factorization approach. We will present a general analysis about the two-body hadronic decays of the heavy $B_c$ meson and also provide some expectations for the future developments.
[ { "created": "Tue, 31 Dec 2013 14:29:00 GMT", "version": "v1" }, { "created": "Fri, 28 Feb 2014 14:02:27 GMT", "version": "v2" }, { "created": "Thu, 31 Jul 2014 17:50:40 GMT", "version": "v3" } ]
2014-08-01
[ [ "Xiao", "Zhen-Jun", "" ], [ "Liu", "Xin", "" ] ]
Along with the running of Large Hadron Collider (LHC) located at CERN in November 2009, a large number of data samples of $B_c$ meson have been collected and some hadronic $B_c$ decay modes have been measured by the LHC experiments. In view of the special and important roles of $B_c$ meson decays playing in the heavy flavor sector, we here give a short review on the status of two body hadronic decays $B_c \to M_1 M_2$ at both experimental and theoretical aspects. For the theoretical progresses, specifically, we will show lots of theoretical studies on two body hadronic $B_c$ decays involving pseudoscalar, vector, scalar, axial-vector, even tensor meson(s) in the final states by employing the perturbative QCD (pQCD) factorization approach. We will present a general analysis about the two-body hadronic decays of the heavy $B_c$ meson and also provide some expectations for the future developments.
hep-ph/0306264
Ernest Ma
Ernest Ma (UC Riverside), G. Rajasekaran (IMSC, Chennai)
New "Square Root" Model of Lepton Family Cyclic Symmetry
10 pages, no figure
Phys.Rev. D68 (2003) 071302
10.1103/PhysRevD.68.071302
UCRHEP-T356 (June 2003)
hep-ph
null
Following the newly formulated notion of form invariance of the neutrino mass matrix, a complete model of leptons is constructed. It is based on a specific unitary 3 X 3 matrix U in family space, such that U^2 is the simple discrete symmetry nu_e to -nu_e, nu_mu to nu_tau. Thus U also generates the cyclic group Z_4. The charged-lepton mass matrix is nearly diagonal while the neutrino mass matrix is of the form suitable for explaining maximal (large) mixing in atmospheric (solar) neutrino oscillations in the context of three nearly degenerate neutrino masses. Observable lepton flavor violation is predicted. Quarks may be treated in the same way as the charged leptons.
[ { "created": "Thu, 26 Jun 2003 14:40:00 GMT", "version": "v1" } ]
2009-11-10
[ [ "Ma", "Ernest", "", "UC Riverside" ], [ "Rajasekaran", "G.", "", "IMSC, Chennai" ] ]
Following the newly formulated notion of form invariance of the neutrino mass matrix, a complete model of leptons is constructed. It is based on a specific unitary 3 X 3 matrix U in family space, such that U^2 is the simple discrete symmetry nu_e to -nu_e, nu_mu to nu_tau. Thus U also generates the cyclic group Z_4. The charged-lepton mass matrix is nearly diagonal while the neutrino mass matrix is of the form suitable for explaining maximal (large) mixing in atmospheric (solar) neutrino oscillations in the context of three nearly degenerate neutrino masses. Observable lepton flavor violation is predicted. Quarks may be treated in the same way as the charged leptons.
hep-ph/0302211
Alexey Gulov
V.I. Demchik, A.V. Gulov, V.V. Skalozub, and A.Yu. Tischenko
Signals of the Abelian Z' boson within the analysis of the LEP2 data
15 pages
Phys.Atom.Nucl. 67 (2004) 1312-1320; Yad.Fiz. 67 (2004) 1335-1343
10.1134/1.1777286
null
hep-ph
null
The preliminary LEP data on the e^+e^- -> l^+l^- scattering are analysed to establish a model-independent search for the signals of virtual states of the Abelian Z' boson. The recently introduced observables give a possibility to pick up uniquely the Abelian Z' signals in these processes. The mean values of the observables are in accordance with the Z' existence. However, the accuracy of the experimental data is deficient to detect the signal at more than the 1\sigma confidence level. The results of other model-independent fits and further prospects are discussed.
[ { "created": "Mon, 24 Feb 2003 16:12:09 GMT", "version": "v1" } ]
2009-11-10
[ [ "Demchik", "V. I.", "" ], [ "Gulov", "A. V.", "" ], [ "Skalozub", "V. V.", "" ], [ "Tischenko", "A. Yu.", "" ] ]
The preliminary LEP data on the e^+e^- -> l^+l^- scattering are analysed to establish a model-independent search for the signals of virtual states of the Abelian Z' boson. The recently introduced observables give a possibility to pick up uniquely the Abelian Z' signals in these processes. The mean values of the observables are in accordance with the Z' existence. However, the accuracy of the experimental data is deficient to detect the signal at more than the 1\sigma confidence level. The results of other model-independent fits and further prospects are discussed.
hep-ph/9709254
null
Leszek Motyka, Kacper Zalewski
Mass spectra and leptonic decay widths of heavy quarkonia
Latex file, 19 pages; Zs. f. Ph. C in print
Eur.Phys.J.C4:107-114,1998
10.1007/s100520050190
TPJU - 8/97
hep-ph
null
A nonrelativistic Hamiltonian with plausible spin dependent corrections is proposed for the quarkonia below their respective strong decay thresholds. With only six free parameters this model reproduces the nine known masses of the bottomonia within about 1 MeV, the six known masses of the charmonia within a few MeV and the five known leptonic decay widths of the ${}^3S_1$ states within about {20 %}. The model is then used to predict the masses of the remaining 43 quarkonia (some of them for the first time) and of the leptonic decay widths of the two ${}^1S_0(\bar{b}c)$ states. Comparison with some other models is made.
[ { "created": "Fri, 5 Sep 1997 11:58:00 GMT", "version": "v1" } ]
2011-09-13
[ [ "Motyka", "Leszek", "" ], [ "Zalewski", "Kacper", "" ] ]
A nonrelativistic Hamiltonian with plausible spin dependent corrections is proposed for the quarkonia below their respective strong decay thresholds. With only six free parameters this model reproduces the nine known masses of the bottomonia within about 1 MeV, the six known masses of the charmonia within a few MeV and the five known leptonic decay widths of the ${}^3S_1$ states within about {20 %}. The model is then used to predict the masses of the remaining 43 quarkonia (some of them for the first time) and of the leptonic decay widths of the two ${}^1S_0(\bar{b}c)$ states. Comparison with some other models is made.
hep-ph/9709273
null
V. Zanchin, A. Maia Jr., W. Craig and R. Brandenberger (Brown Univ.)
Reheating in the Presence of Noise
26 pages, 2 figures, uses LATEX
Phys.Rev. D57 (1998) 4651-4662
10.1103/PhysRevD.57.4651
BROWN-HET-1072
hep-ph astro-ph
null
Explosive particle production due to parametric resonance is a crucial feature of reheating in inflationary cosmology. Coherent oscillations of the inflaton field act as a periodically varying mass in the evolution equation for matter fields which couple to the inflaton. This in turn results in the parametric resonance instability. Thermal and quantum noise will lead to a nonperiodic perturbation in the mass. We study the resulting equation for the evolution of matter fields and demonstrate that noise (at least if it is temporally uncorrelated) will increase the rate of particle production. We also estimate the limits on the magnitude of the noise for which the resonant behavior is qualitatively unchanged.
[ { "created": "Sun, 7 Sep 1997 16:17:42 GMT", "version": "v1" } ]
2009-10-30
[ [ "Zanchin", "V.", "", "Brown Univ." ], [ "Maia", "A.", "Jr.", "Brown Univ." ], [ "Craig", "W.", "", "Brown Univ." ], [ "Brandenberger", "R.", "", "Brown Univ." ] ]
Explosive particle production due to parametric resonance is a crucial feature of reheating in inflationary cosmology. Coherent oscillations of the inflaton field act as a periodically varying mass in the evolution equation for matter fields which couple to the inflaton. This in turn results in the parametric resonance instability. Thermal and quantum noise will lead to a nonperiodic perturbation in the mass. We study the resulting equation for the evolution of matter fields and demonstrate that noise (at least if it is temporally uncorrelated) will increase the rate of particle production. We also estimate the limits on the magnitude of the noise for which the resonant behavior is qualitatively unchanged.
1704.07743
Long Ma
Long Ma, Xin Dong, Huan-Zhong Huang, and Yu-Gang Ma
Study of a background reconstruction method for the measurement of D-meson azimuthal angular correlations
13 pages, 7 figures
Nuclear Science and Techniques 32, 61 (2021)
10.1007/s41365-021-00896-w
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study experimental background reconstruction methods for the measurement of $D-\overline{D}$ correlation using a PYTHIA simulation. Like-sign and side-band background methods that are widely used in the experimental measurements of single $D$-meson production yields were deployed for the correlation background study. It is found that the like-sign method which well describes the combinatorial background of single $D^{0}$ meson yields fails to reproduce the correlated background in the $D^{0}-\overline{D^{0}}$ correlation measurement, while the side-band background method yields a good description of the background for both the single $D^0$ yields and of the correlated background of the $D^{0}-\overline{D^{0}}$ correlation measurement.
[ { "created": "Mon, 24 Apr 2017 17:06:11 GMT", "version": "v1" }, { "created": "Sat, 26 Jun 2021 09:57:30 GMT", "version": "v2" } ]
2021-06-29
[ [ "Ma", "Long", "" ], [ "Dong", "Xin", "" ], [ "Huang", "Huan-Zhong", "" ], [ "Ma", "Yu-Gang", "" ] ]
We study experimental background reconstruction methods for the measurement of $D-\overline{D}$ correlation using a PYTHIA simulation. Like-sign and side-band background methods that are widely used in the experimental measurements of single $D$-meson production yields were deployed for the correlation background study. It is found that the like-sign method which well describes the combinatorial background of single $D^{0}$ meson yields fails to reproduce the correlated background in the $D^{0}-\overline{D^{0}}$ correlation measurement, while the side-band background method yields a good description of the background for both the single $D^0$ yields and of the correlated background of the $D^{0}-\overline{D^{0}}$ correlation measurement.
hep-ph/0112069
Mingzhe Li
Mingzhe Li, Xiulian Wang, Bo Feng and Xinmin Zhang
Quintessence and Spontaneous Leptogenesis
7pages,1figure
Phys.Rev. D65 (2002) 103511
10.1103/PhysRevD.65.103511
null
hep-ph astro-ph
null
We propose in this paper a scenario of spontaneous baryogenesis in cosmological models of Quintessence by introducing a derivative coupling of the Quintessence scalar $Q$ to the baryon current $J_B^{\mu}$ or the current of the baryon number minus lepton number $J_{B-L}^{\mu}$. We find that with a dimension-5 operator ${\partial_\mu Q} J_{B-L}^{\mu}$ suppressed by the Planck mass $M_{pl}$ or the Grand Unification Scale $M_{GUT}$, baryon number asymmetry $n_B/s \sim 10^{-10}$ can be naturally explained {\it via} leptogenesis. We study also the isocurvature baryon number fluctuation generated in our model.
[ { "created": "Wed, 5 Dec 2001 04:22:44 GMT", "version": "v1" } ]
2009-11-07
[ [ "Li", "Mingzhe", "" ], [ "Wang", "Xiulian", "" ], [ "Feng", "Bo", "" ], [ "Zhang", "Xinmin", "" ] ]
We propose in this paper a scenario of spontaneous baryogenesis in cosmological models of Quintessence by introducing a derivative coupling of the Quintessence scalar $Q$ to the baryon current $J_B^{\mu}$ or the current of the baryon number minus lepton number $J_{B-L}^{\mu}$. We find that with a dimension-5 operator ${\partial_\mu Q} J_{B-L}^{\mu}$ suppressed by the Planck mass $M_{pl}$ or the Grand Unification Scale $M_{GUT}$, baryon number asymmetry $n_B/s \sim 10^{-10}$ can be naturally explained {\it via} leptogenesis. We study also the isocurvature baryon number fluctuation generated in our model.
0808.1605
Sourabh Dube
Sourabh Dube, Julian Glatzer, Sunil Somalwar, Alexander Sood, Scott Thomas
Addressing the Multi-Channel Inverse Problem at High Energy Colliders: A Model Independent Approach to the Search for New Physics with Trileptons
17 pages, 7 figures Changed content cosmetic changes for submission to JHEP
null
10.1088/0954-3899/39/8/085004
NHETC-2008-39
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We describe a method for interpreting trilepton searches at high energy colliders in a model-independent fashion and apply it to the recent searches at the Tevatron. The key step is to recognize that the trilepton signature is comprised of four experimentally very different channels defined by the number of tau-leptons in the trilepton state. Contributions from these multiple channels to the overall experimental sensitivity (cross section times branching ratio) are model-independent and can be parametrized in terms of relevant new particle masses. Given the trileptonic branching ratios of a specific model, these experimentally obtained multichannel sensitivities can be combined to obtain a cross section measurement that can be used to confront the model with data. Our model-independent results are more widely applicable than the current Tevatron trilepton results which are stated exclusively in terms of mSUGRA parameters of supersymmetry. The technique presented here can be expanded beyond trilepton searches to the more general "inverse problem" of experimentally discriminating between competing models that seek to explain new physics discovered in multiple channels.
[ { "created": "Tue, 12 Aug 2008 02:50:52 GMT", "version": "v1" }, { "created": "Sat, 25 Jul 2009 01:07:53 GMT", "version": "v2" }, { "created": "Mon, 24 Aug 2009 21:35:47 GMT", "version": "v3" }, { "created": "Thu, 2 Feb 2012 15:48:29 GMT", "version": "v4" }, { "created": "Thu, 5 Apr 2012 22:12:10 GMT", "version": "v5" } ]
2015-05-13
[ [ "Dube", "Sourabh", "" ], [ "Glatzer", "Julian", "" ], [ "Somalwar", "Sunil", "" ], [ "Sood", "Alexander", "" ], [ "Thomas", "Scott", "" ] ]
We describe a method for interpreting trilepton searches at high energy colliders in a model-independent fashion and apply it to the recent searches at the Tevatron. The key step is to recognize that the trilepton signature is comprised of four experimentally very different channels defined by the number of tau-leptons in the trilepton state. Contributions from these multiple channels to the overall experimental sensitivity (cross section times branching ratio) are model-independent and can be parametrized in terms of relevant new particle masses. Given the trileptonic branching ratios of a specific model, these experimentally obtained multichannel sensitivities can be combined to obtain a cross section measurement that can be used to confront the model with data. Our model-independent results are more widely applicable than the current Tevatron trilepton results which are stated exclusively in terms of mSUGRA parameters of supersymmetry. The technique presented here can be expanded beyond trilepton searches to the more general "inverse problem" of experimentally discriminating between competing models that seek to explain new physics discovered in multiple channels.
2203.07563
Michael J. Longo
Michael J. Longo
Neutron size from high energy scattering data
Submitted to Physical. Rev. Comments
null
null
null
hep-ph hep-ex
http://creativecommons.org/licenses/by/4.0/
Alvarado, Aranda, and Bonilla propose a sub-GeV U(1)R gauge boson model to explain the proton charge radius discrepancy. Their model assumes opposite sign U(1)R charge assignments for up and down quarks in the nucleon. I point out that might cause a difference between neutron and proton mass radii that contradicts existing p-p and n-p scattering data. Using existing neutron and proton scattering data I show that the neutron and proton mass radii are equal within about 2%. This constitutes a challenge to models that attempt to explain the discrepancy by modifying the quark couplings.
[ { "created": "Tue, 15 Mar 2022 00:08:57 GMT", "version": "v1" } ]
2022-03-16
[ [ "Longo", "Michael J.", "" ] ]
Alvarado, Aranda, and Bonilla propose a sub-GeV U(1)R gauge boson model to explain the proton charge radius discrepancy. Their model assumes opposite sign U(1)R charge assignments for up and down quarks in the nucleon. I point out that might cause a difference between neutron and proton mass radii that contradicts existing p-p and n-p scattering data. Using existing neutron and proton scattering data I show that the neutron and proton mass radii are equal within about 2%. This constitutes a challenge to models that attempt to explain the discrepancy by modifying the quark couplings.
1609.09402
Jue Zhang
Stephen F. King, Jue Zhang and Shun Zhou
Renormalisation Group Corrections to the Littlest Seesaw Model and Maximal Atmospheric Mixing
28 pages, 4 figures, 5 tables; v2: references added, include the scenario where both mass scales of right-handed neutrinos are varied, version to be published in JHEP
JHEP 12 (2016) 023
10.1007/JHEP12(2016)023
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Littlest Seesaw (LS) model involves two right-handed neutrinos and a very constrained Dirac neutrino mass matrix, involving one texture zero and two independent Dirac masses, leading to a highly predictive scheme in which all neutrino masses and the entire PMNS matrix is successfully predicted in terms of just two real parameters. We calculate the renormalisation group (RG) corrections to the LS predictions, with and without supersymmetry, including also the threshold effects induced by the decoupling of heavy Majorana neutrinos both analytically and numerically. We find that the predictions for neutrino mixing angles and mass ratios are rather stable under RG corrections. For example we find that the LS model with RG corrections predicts close to maximal atmospheric mixing, $\theta_{23}=45^\circ \pm 1^\circ$, in most considered cases, in tension with the latest NOvA results. The techniques used here apply to other seesaw models with a strong normal mass hierarchy.
[ { "created": "Thu, 29 Sep 2016 16:01:42 GMT", "version": "v1" }, { "created": "Tue, 29 Nov 2016 13:14:41 GMT", "version": "v2" } ]
2016-12-12
[ [ "King", "Stephen F.", "" ], [ "Zhang", "Jue", "" ], [ "Zhou", "Shun", "" ] ]
The Littlest Seesaw (LS) model involves two right-handed neutrinos and a very constrained Dirac neutrino mass matrix, involving one texture zero and two independent Dirac masses, leading to a highly predictive scheme in which all neutrino masses and the entire PMNS matrix is successfully predicted in terms of just two real parameters. We calculate the renormalisation group (RG) corrections to the LS predictions, with and without supersymmetry, including also the threshold effects induced by the decoupling of heavy Majorana neutrinos both analytically and numerically. We find that the predictions for neutrino mixing angles and mass ratios are rather stable under RG corrections. For example we find that the LS model with RG corrections predicts close to maximal atmospheric mixing, $\theta_{23}=45^\circ \pm 1^\circ$, in most considered cases, in tension with the latest NOvA results. The techniques used here apply to other seesaw models with a strong normal mass hierarchy.
0809.0404
Kausik Pal
Kausik Pal, Subhrajyoti Biswas, Abhee K. Dutt-Mazumder
Spin dependent Fermi Liquid parameters and properties of polarized quark matter
20 pages, 8 figures, references added, to appear in Physical Review C
Phys.Rev.C79:015205,2009
10.1103/PhysRevC.79.015205
null
hep-ph astro-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We calculate the spin dependent Fermi liquid parameters (FLPs), single particle energies and energy densities of various spin states of polarized quark matter. The expressions for the incompressibility($K$) and sound velocity ($c_1$) in terms of the spin dependent FLPs and polarization parameter $(\xi)$ are derived. Estimated values of $K$ and $c_1$ reveal that the equation of state (EOS) of the polarized matter is stiffer than the unpolarized one. Finally we investigate the possibility of the spin polarization (ferromagnetism) phase transition.
[ { "created": "Tue, 2 Sep 2008 11:24:32 GMT", "version": "v1" }, { "created": "Mon, 5 Jan 2009 11:50:39 GMT", "version": "v2" } ]
2009-01-28
[ [ "Pal", "Kausik", "" ], [ "Biswas", "Subhrajyoti", "" ], [ "Dutt-Mazumder", "Abhee K.", "" ] ]
We calculate the spin dependent Fermi liquid parameters (FLPs), single particle energies and energy densities of various spin states of polarized quark matter. The expressions for the incompressibility($K$) and sound velocity ($c_1$) in terms of the spin dependent FLPs and polarization parameter $(\xi)$ are derived. Estimated values of $K$ and $c_1$ reveal that the equation of state (EOS) of the polarized matter is stiffer than the unpolarized one. Finally we investigate the possibility of the spin polarization (ferromagnetism) phase transition.
1010.0692
Masaki Asano
Masaki Asano, Hyung Do Kim, Ryuichiro Kitano, Yasuhiro Shimizu
Natural Supersymmetry at the LHC
19 pages, 6 figures, 1 table
JHEP 1012:019,2010
10.1007/JHEP12(2010)019
TU-873
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
If the minimal supersymmetric standard model is the solution to the hierarchy problem, the scalar top quark (stop) and the Higgsino should weigh around the electroweak scale such as 200 GeV. A low messenger scale, which results in a light gravitino, is also suggested to suppress the quantum corrections to the Higgs mass parameters. Therefore the minimal model for natural supersymmetry is a system with stop/Higgsino/gravitino whereas other superparticles are heavy. We study the LHC signatures of the minimal system and discuss the discovery potential and methods for the mass measurements.
[ { "created": "Mon, 4 Oct 2010 20:13:55 GMT", "version": "v1" } ]
2015-03-17
[ [ "Asano", "Masaki", "" ], [ "Kim", "Hyung Do", "" ], [ "Kitano", "Ryuichiro", "" ], [ "Shimizu", "Yasuhiro", "" ] ]
If the minimal supersymmetric standard model is the solution to the hierarchy problem, the scalar top quark (stop) and the Higgsino should weigh around the electroweak scale such as 200 GeV. A low messenger scale, which results in a light gravitino, is also suggested to suppress the quantum corrections to the Higgs mass parameters. Therefore the minimal model for natural supersymmetry is a system with stop/Higgsino/gravitino whereas other superparticles are heavy. We study the LHC signatures of the minimal system and discuss the discovery potential and methods for the mass measurements.
hep-ph/0001109
Merab Gogberashvili
Merab Gogberashvili
Brane-Universe in Six Dimensions with Two Times
6 pages, latex, no figures
Phys.Lett. B484 (2000) 124-128
10.1016/S0370-2693(00)00614-6
null
hep-ph gr-qc hep-th
null
Brane-Universe model embedded in 6-dimensional space-time with the signature (2+4) is considered. A matter is gravitationally trapped in three space dimensions, but both time-like directions are open. Choosing of the dimension and the signature of the model is initiated with the conformal symmetry for massless particles and any point in our world can be (1+1) string-like object.
[ { "created": "Thu, 13 Jan 2000 08:01:16 GMT", "version": "v1" } ]
2009-10-31
[ [ "Gogberashvili", "Merab", "" ] ]
Brane-Universe model embedded in 6-dimensional space-time with the signature (2+4) is considered. A matter is gravitationally trapped in three space dimensions, but both time-like directions are open. Choosing of the dimension and the signature of the model is initiated with the conformal symmetry for massless particles and any point in our world can be (1+1) string-like object.
hep-ph/9611361
null
Yu. S. Kalashnikova and A. V. Nefediev (ITEP, Moscow)
Relativistic quantum mechanics in the einbein field formalism
LaTeX 2.09, 16 pages, no figures
Phys.Atom.Nucl. 60 (1997) 1389-1394; Yad.Fiz. 60 (1997) 1529-1535
null
ITEP-45-96
hep-ph
null
The system of two relativistic particles with einbein fields is quantized as a constrained system.A method of the introduction of the Newton--Wigner collective coordinate is discussed in presence of different gauge fixing conditions. Some arguments are involved in the favour of Lorents covariant gauge fixing conditions.
[ { "created": "Tue, 19 Nov 1996 12:37:21 GMT", "version": "v1" } ]
2007-05-23
[ [ "Kalashnikova", "Yu. S.", "", "ITEP, Moscow" ], [ "Nefediev", "A. V.", "", "ITEP, Moscow" ] ]
The system of two relativistic particles with einbein fields is quantized as a constrained system.A method of the introduction of the Newton--Wigner collective coordinate is discussed in presence of different gauge fixing conditions. Some arguments are involved in the favour of Lorents covariant gauge fixing conditions.
2110.02241
Fabian Rennecke
Swagato Mukherjee, Fabian Rennecke and Vladimir V. Skokov
Analytical structure of the equation of state at finite density: Resummation versus expansion in a low energy model
9 pages, 9 figures; matches the published version
null
10.1103/PhysRevD.105.014026
null
hep-ph hep-lat hep-th nucl-th
http://creativecommons.org/licenses/by/4.0/
For theories plagued with a sign problem at finite density, a Taylor expansion in the chemical potential is frequently used for lattice gauge theory based computations of the equation of state. Recently, in arXiv:2106.03165, a new resummation scheme was proposed for such an expansion that resums contributions of correlation functions of conserved currents to all orders in the chemical potential. Here, we study the efficacy of this resummation scheme using a solvable low energy model, namely the mean-field quark-meson model. After adapting the scheme for a mean-field analysis, we confront the results of this scheme with the direct solution of the model at finite density as well as compare with results from Taylor expansions. We study to what extent the two methods capture the analytical properties of the equation of state in the complex chemical potential plane. As expected, the Taylor expansion breaks down as soon as the baryon chemical potential reaches the radius of convergence defined by the Yang-Lee edge singularity. Encouragingly, the resummation not only captures the location of the Yang-Lee edge singularity accurately, but is also able to describe the equation of state for larger chemical potentials beyond the location of the edge singularity for a wide range of temperatures.
[ { "created": "Tue, 5 Oct 2021 18:00:13 GMT", "version": "v1" }, { "created": "Mon, 28 Mar 2022 20:44:57 GMT", "version": "v2" } ]
2022-03-30
[ [ "Mukherjee", "Swagato", "" ], [ "Rennecke", "Fabian", "" ], [ "Skokov", "Vladimir V.", "" ] ]
For theories plagued with a sign problem at finite density, a Taylor expansion in the chemical potential is frequently used for lattice gauge theory based computations of the equation of state. Recently, in arXiv:2106.03165, a new resummation scheme was proposed for such an expansion that resums contributions of correlation functions of conserved currents to all orders in the chemical potential. Here, we study the efficacy of this resummation scheme using a solvable low energy model, namely the mean-field quark-meson model. After adapting the scheme for a mean-field analysis, we confront the results of this scheme with the direct solution of the model at finite density as well as compare with results from Taylor expansions. We study to what extent the two methods capture the analytical properties of the equation of state in the complex chemical potential plane. As expected, the Taylor expansion breaks down as soon as the baryon chemical potential reaches the radius of convergence defined by the Yang-Lee edge singularity. Encouragingly, the resummation not only captures the location of the Yang-Lee edge singularity accurately, but is also able to describe the equation of state for larger chemical potentials beyond the location of the edge singularity for a wide range of temperatures.
hep-ph/0011183
Jon Rosner
Jonathan L. Rosner
Factorization vs. Flavor SU(3) in Charmless B Decays
18 pages, LaTeX, 1 figure, to be published in Proceedings of Beauty 2000, Kibbutz Maagan, Israel, September 13-18, 2000, edited by S. Erhan, Y. Rozen, and P. E. Schlein, Nucl. Inst. Meth. A, 2001
Nucl.Instrum.Meth.A462:44-51,2001
10.1016/S0168-9002(01)00022-5
EFI 2000-41
hep-ph
null
Two types of predictions for charmless B decays are compared. One involves estimates based on factorization and models for form factors, while the other involves the use of flavor SU(3), sometimes with assumptions about the smallness of certain amplitudes. After a comparison of some factorization predictions with recent data, specific decays of $B$ mesons to two charmless mesons are discussed.
[ { "created": "Tue, 14 Nov 2000 23:11:39 GMT", "version": "v1" } ]
2011-03-23
[ [ "Rosner", "Jonathan L.", "" ] ]
Two types of predictions for charmless B decays are compared. One involves estimates based on factorization and models for form factors, while the other involves the use of flavor SU(3), sometimes with assumptions about the smallness of certain amplitudes. After a comparison of some factorization predictions with recent data, specific decays of $B$ mesons to two charmless mesons are discussed.
hep-ph/0212161
N. Nikolaev
I.P. Ivanov (Inst. Math., Novosibirsk), N.N. Nikolaev (IKP, Juelich and Landau Inst., Chernogolovka), W. Sch\"afer (IKP, Juelich), B.G. Zakharov (Landau Inst., Chernogolovka), V.R. Zoller (ITEP, Moscow)
Lectures on Diffraction and Saturation of Nuclear Partons in DIS off Heavy Nuclei
The notes of lectures presented by N.N.N. at the XXXVI St.Petersburg Nuclear Physics Institute Winter School on Nuclear and Particle Physics & VIII St.Petersburg School on Theoretical Physics, St.Petersburg, Repino, February 25 - March 3, 2002, 36 pages, 10 figures. Several typos corrected
null
null
null
hep-ph hep-ex nucl-ex nucl-th
null
The Lorentz contraction of ultrarelativistic nuclei entails a spatial overlap and fusion (recombination, saturation) of partons belonging to different nucleons at the same impact parameter. In these lectures we present a consistent description of the fusion of partons in terms of nuclear attenuation of color dipole states of the photon and collective Weizs\"acker-Williams (WW) gluon structure function of a nucleus. The point that all observables for DIS off nuclei are uniquely calculable in terms of the nuclear WW glue amounts to a new form of factorization in the saturation regime. We start with the theory of multichannel propagation of color dipoles in a nuclear medium including the color-singlet to color-octet to color-octet transitions. We show how the Glauber-Gribov formulas are recovered from the multichannel formalism. Then we derive the two-plateau momentum distribution of final state (FS) quarks produced in deep inelastic scattering (DIS) off nuclei in the saturation regime. Then we comment on the signatures of saturation in exclusive diffractive DIS. A large body of these lectures is on the recent theory of jet-jet inclusive cross sections. We show that for hard dijets the decorrelation momentum is of the order of the nuclear saturation momentum $Q_A$. For minijets with the transverse momentum below the saturation scale we predict a complete disappearance of the azimuthal jet-jet correlation. We conclude with comment on a possible relevance of the decorrelation of jets to the experimental data from the STAR-RHIC Collaboration.
[ { "created": "Wed, 11 Dec 2002 17:44:08 GMT", "version": "v1" }, { "created": "Thu, 10 Apr 2003 16:07:50 GMT", "version": "v2" } ]
2007-05-23
[ [ "Ivanov", "I. P.", "", "Inst. Math., Novosibirsk" ], [ "Nikolaev", "N. N.", "", "IKP, Juelich\n and Landau Inst., Chernogolovka" ], [ "Schäfer", "W.", "", "IKP, Juelich" ], [ "Zakharov", "B. G.", "", "Landau Inst., Chernogolovka" ], [ "Zoller", "V. R.", "", "ITEP, Moscow" ] ]
The Lorentz contraction of ultrarelativistic nuclei entails a spatial overlap and fusion (recombination, saturation) of partons belonging to different nucleons at the same impact parameter. In these lectures we present a consistent description of the fusion of partons in terms of nuclear attenuation of color dipole states of the photon and collective Weizs\"acker-Williams (WW) gluon structure function of a nucleus. The point that all observables for DIS off nuclei are uniquely calculable in terms of the nuclear WW glue amounts to a new form of factorization in the saturation regime. We start with the theory of multichannel propagation of color dipoles in a nuclear medium including the color-singlet to color-octet to color-octet transitions. We show how the Glauber-Gribov formulas are recovered from the multichannel formalism. Then we derive the two-plateau momentum distribution of final state (FS) quarks produced in deep inelastic scattering (DIS) off nuclei in the saturation regime. Then we comment on the signatures of saturation in exclusive diffractive DIS. A large body of these lectures is on the recent theory of jet-jet inclusive cross sections. We show that for hard dijets the decorrelation momentum is of the order of the nuclear saturation momentum $Q_A$. For minijets with the transverse momentum below the saturation scale we predict a complete disappearance of the azimuthal jet-jet correlation. We conclude with comment on a possible relevance of the decorrelation of jets to the experimental data from the STAR-RHIC Collaboration.
hep-ph/9802274
Vladimir Shevchenko
V.I.Shevchenko (ITEP)
QCD Field Strength Correlator at the One-Loop Order
LaTeX, 13 pages, 2 eps figures; comments added
null
null
ITEP-PH-01-98
hep-ph
null
The leading perturbative contributions into the two-point gauge-invariant correlator $Tr<gF(x)U(x,0)U(0,y)F(y)U(y,0)U(0,x)>$ are calculated at the one-loop order. It is shown, that nonlocal condensate is nonzero at this order. The relation with the renormalization properties of Wilson loops is discussed.
[ { "created": "Mon, 9 Feb 1998 11:46:24 GMT", "version": "v1" }, { "created": "Thu, 12 Feb 1998 16:21:01 GMT", "version": "v2" }, { "created": "Wed, 18 Mar 1998 13:32:37 GMT", "version": "v3" } ]
2007-05-23
[ [ "Shevchenko", "V. I.", "", "ITEP" ] ]
The leading perturbative contributions into the two-point gauge-invariant correlator $Tr<gF(x)U(x,0)U(0,y)F(y)U(y,0)U(0,x)>$ are calculated at the one-loop order. It is shown, that nonlocal condensate is nonzero at this order. The relation with the renormalization properties of Wilson loops is discussed.
hep-ph/9607285
Cheuk-Yin Wong
Cheuk-Yin Wong (Oak Ridge National Laboratory)
Suppression of J/psi and Psi' Production in High-Energy Pb on Pb Collisions
4 pages (REVTeX), includes 3 eps figures; revised to update results
Phys.Rev.C55:2621-2624,1997
10.1103/PhysRevC.55.2621
ORNL-CTP-96-07
hep-ph nucl-th
null
The anomalous J/psi suppression in Pb-Pb collisions at 158A GeV observed recently by NA50 can be explained as due to the transition to a new phase of strong J/psi absorption, which sets in when the local energy density exceeds about 3.4 GeV/fm**3.
[ { "created": "Wed, 10 Jul 1996 21:25:01 GMT", "version": "v1" }, { "created": "Fri, 13 Dec 1996 16:44:44 GMT", "version": "v2" } ]
2008-11-26
[ [ "Wong", "Cheuk-Yin", "", "Oak Ridge National Laboratory" ] ]
The anomalous J/psi suppression in Pb-Pb collisions at 158A GeV observed recently by NA50 can be explained as due to the transition to a new phase of strong J/psi absorption, which sets in when the local energy density exceeds about 3.4 GeV/fm**3.
hep-ph/9702295
Rizos Ioannis
J. Rizos(SISSA & Ioannina) and K. Tamvakis (Ioannina)
String scale unification in an SU(6)xSU(2) GUT
15 pages, Latex2e, three figures included, comments added, published version
Phys.Lett. B414 (1997) 277-287
10.1016/S0370-2693(97)01181-7
SISSA/107/96/EP
hep-ph
null
We construct and analyze an $SU(6)\times SU(2)$ GUT. The model is k=1 string embedable in the sense that we employ only chiral representations allowed at the k=1 level of the associated Ka\v{c}-Moody Algebra. Both cases $SU(6)\times SU(2)_{L}$ and $SU(6)\times SU(2)_{R}$ are realized. The model is characterized by the $SU(6)\times SU(2) \to SU(4)\times SU(2)\times SU(2)$ breaking scale $M_X$, and the $SU(4)\times SU(2)\times SU(2) \to SU(3)_{C}\times SU(2)_{L}\times U(1)_{Y}$ breaking scale $M_{R}$ . The spectrum bellow $M_R$ includes an extra pair of charge-1/3 colour-triplets of mass $M_{I}\leq M_{R}$ that does not couple to matter fields and, possibly, an extra pair of isodoublets. Above $M_{X}$ the SU(6) and SU(2) gauge couplings always unify at a scale which can be taken to be the string unification scale $M_{s}\sim 5\times 10^{17} GeV$. The model has Yukawa coupling unification since quarks and leptons obtain their masses from a single Yukawa coupling. Neutrinos obtain acceptably small masses through a see-saw mechanism. Coloured triplets that couple to matter fields are naturally split from the coexisting isodoublets without the need of any numerical fine tuning.
[ { "created": "Mon, 10 Feb 1997 12:02:51 GMT", "version": "v1" }, { "created": "Wed, 26 Feb 1997 15:43:25 GMT", "version": "v2" }, { "created": "Mon, 26 Jan 1998 08:34:09 GMT", "version": "v3" } ]
2009-10-30
[ [ "Rizos", "J.", "", "SISSA & Ioannina" ], [ "Tamvakis", "K.", "", "Ioannina" ] ]
We construct and analyze an $SU(6)\times SU(2)$ GUT. The model is k=1 string embedable in the sense that we employ only chiral representations allowed at the k=1 level of the associated Ka\v{c}-Moody Algebra. Both cases $SU(6)\times SU(2)_{L}$ and $SU(6)\times SU(2)_{R}$ are realized. The model is characterized by the $SU(6)\times SU(2) \to SU(4)\times SU(2)\times SU(2)$ breaking scale $M_X$, and the $SU(4)\times SU(2)\times SU(2) \to SU(3)_{C}\times SU(2)_{L}\times U(1)_{Y}$ breaking scale $M_{R}$ . The spectrum bellow $M_R$ includes an extra pair of charge-1/3 colour-triplets of mass $M_{I}\leq M_{R}$ that does not couple to matter fields and, possibly, an extra pair of isodoublets. Above $M_{X}$ the SU(6) and SU(2) gauge couplings always unify at a scale which can be taken to be the string unification scale $M_{s}\sim 5\times 10^{17} GeV$. The model has Yukawa coupling unification since quarks and leptons obtain their masses from a single Yukawa coupling. Neutrinos obtain acceptably small masses through a see-saw mechanism. Coloured triplets that couple to matter fields are naturally split from the coexisting isodoublets without the need of any numerical fine tuning.
hep-ph/9908413
Sandy Donnachie
A. Donnachie, H.G. Dosch, M. Rueter
Gamma*Gamma* Reactions at High Energies
21 pages, 5 figures
Eur.Phys.J.C13:141-150,2000
10.1007/s100520000268
null
hep-ph
null
The total hadronic gamma*gamma* cross sections at high energy are calculated as a function of energy and photon virtuality in a model combining Regge exchange, the quark box diagram (a fixed pole in Regge language) and soft and hard pomeron exchanges evaluated in the context of dipole-dipole scattering. Good agreement is obtained with the data for the real gamma-gamma cross section and for the real photon structure function. However the model prediction for the gamma* gamma* cross section is too small. This is attributed to an incorrect extrapolation of the Q^2 dependence of the hard pomeron adopted here. Parametrising it independently shows that the hard part of the cross section can be well represented by a simple Regge pole with intercept ~ 1.3.
[ { "created": "Thu, 19 Aug 1999 13:45:40 GMT", "version": "v1" } ]
2015-06-25
[ [ "Donnachie", "A.", "" ], [ "Dosch", "H. G.", "" ], [ "Rueter", "M.", "" ] ]
The total hadronic gamma*gamma* cross sections at high energy are calculated as a function of energy and photon virtuality in a model combining Regge exchange, the quark box diagram (a fixed pole in Regge language) and soft and hard pomeron exchanges evaluated in the context of dipole-dipole scattering. Good agreement is obtained with the data for the real gamma-gamma cross section and for the real photon structure function. However the model prediction for the gamma* gamma* cross section is too small. This is attributed to an incorrect extrapolation of the Q^2 dependence of the hard pomeron adopted here. Parametrising it independently shows that the hard part of the cross section can be well represented by a simple Regge pole with intercept ~ 1.3.
hep-ph/0102224
Andrei Belitsky
A.V. Belitsky, D. M\"uller
Resummation of target mass corrections in two-photon processes: twist-two sector
11 pages, LaTeX, no figures
Phys.Lett. B507 (2001) 173-182
10.1016/S0370-2693(01)00425-7
null
hep-ph
null
We develop a formalism for the resummation of target mass corrections in off-forward two-photon amplitudes given by a chronological product of electromagnetic currents, arising in e.g. deeply virtual Compton scattering. The method is based on a relation of composite operators with a definite twist to harmonic tensors, which form an irreducible representation of the Lorentz group. We give an application of the framework for the matrix elements of twist-two operators.
[ { "created": "Sun, 18 Feb 2001 19:39:05 GMT", "version": "v1" }, { "created": "Thu, 22 Feb 2001 13:51:11 GMT", "version": "v2" } ]
2009-11-07
[ [ "Belitsky", "A. V.", "" ], [ "Müller", "D.", "" ] ]
We develop a formalism for the resummation of target mass corrections in off-forward two-photon amplitudes given by a chronological product of electromagnetic currents, arising in e.g. deeply virtual Compton scattering. The method is based on a relation of composite operators with a definite twist to harmonic tensors, which form an irreducible representation of the Lorentz group. We give an application of the framework for the matrix elements of twist-two operators.
2012.00474
Fabian Krinner
Fabian Michael Krinner and Stephan Paul
New developments in model-independent Partial-Wave Analysis
Proceedings for the 23rd High-Energy Physics International Conference in Quantum ChromoDynamics (QCD 2020), virtually held from October 27th to October 30th in Montpellier, France; five pages, four figures
Nucl.Part.Phys.Proc. 312-317 (2021) 48-52
10.1016/j.nuclphysbps.2021.05.013
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
Partial-wave analyses (PWA) are an essential tool for studying resonance structures in decays with hadronic multi-body final states. For several years, more model-independent approaches to such analyses have been used for various decay final states. However, up to now, these methods have mostly been applied to sub-sets of partial waves, also called freed waves. In this article, we explore possibilities and limitations of extended model-independent approaches. We systematically apply various different fit models to the analysis of pseudo data sets, to study both the impact of the mathematical description used for the freed waves and the choice of simultaneously freed waves. We can show that suitable methods exist, which lift restrictions to only sub-sets of freed partial waves and demonstrate hidden caveats present in previous works.
[ { "created": "Tue, 1 Dec 2020 13:26:33 GMT", "version": "v1" } ]
2021-09-07
[ [ "Krinner", "Fabian Michael", "" ], [ "Paul", "Stephan", "" ] ]
Partial-wave analyses (PWA) are an essential tool for studying resonance structures in decays with hadronic multi-body final states. For several years, more model-independent approaches to such analyses have been used for various decay final states. However, up to now, these methods have mostly been applied to sub-sets of partial waves, also called freed waves. In this article, we explore possibilities and limitations of extended model-independent approaches. We systematically apply various different fit models to the analysis of pseudo data sets, to study both the impact of the mathematical description used for the freed waves and the choice of simultaneously freed waves. We can show that suitable methods exist, which lift restrictions to only sub-sets of freed partial waves and demonstrate hidden caveats present in previous works.
2007.13748
Yuber F. Perez-Gonzalez
Andr\'e de Gouv\^ea, Ivan Martinez-Soler, Yuber F. Perez-Gonzalez, Manibrata Sen
Fundamental physics with the diffuse supernova background neutrinos
21 pages, 11 figures, new channel to measure H0 with neutrinos; references included, small corrections, matches version published in PRD
Phys. Rev. D 102, 123012 (2020)
10.1103/PhysRevD.102.123012
NUHEP-TH/20-08, FERMILAB-PUB-20-353-T
hep-ph astro-ph.CO astro-ph.SR hep-ex
http://creativecommons.org/licenses/by/4.0/
The Universe is awash with tens-of-MeV neutrinos of all species coming from all past core-collapse supernovae. These have never been observed, but this state of affairs will change in the near future. In the less than ten years, the Super-Kamiokande experiment, loaded with gadolinium, is expected to collect dozens of events induced by the scattering of neutrinos from the diffuse supernova neutrino background (DSNB). Next-generation projects, including Hyper-Kamiokande and Theia, are expected to collect data samples with hundreds of DSNB events after a decade of running. Here, we study quantitatively how well the DSNB, including its energy spectrum, will be measured by different current or upcoming large neutrino detectors. We analyze the simulated data in order to estimate how well measurements of the DSNB can be used to inform research topics in cosmology -- including measurements of the Hubble parameter -- astrophysics -- including the star-formation-rate -- and particle physics -- including the neutrino lifetime and the possibility that neutrinos are pseudo-Dirac fermions.
[ { "created": "Mon, 27 Jul 2020 18:00:00 GMT", "version": "v1" }, { "created": "Mon, 7 Dec 2020 18:31:36 GMT", "version": "v2" } ]
2021-01-04
[ [ "de Gouvêa", "André", "" ], [ "Martinez-Soler", "Ivan", "" ], [ "Perez-Gonzalez", "Yuber F.", "" ], [ "Sen", "Manibrata", "" ] ]
The Universe is awash with tens-of-MeV neutrinos of all species coming from all past core-collapse supernovae. These have never been observed, but this state of affairs will change in the near future. In the less than ten years, the Super-Kamiokande experiment, loaded with gadolinium, is expected to collect dozens of events induced by the scattering of neutrinos from the diffuse supernova neutrino background (DSNB). Next-generation projects, including Hyper-Kamiokande and Theia, are expected to collect data samples with hundreds of DSNB events after a decade of running. Here, we study quantitatively how well the DSNB, including its energy spectrum, will be measured by different current or upcoming large neutrino detectors. We analyze the simulated data in order to estimate how well measurements of the DSNB can be used to inform research topics in cosmology -- including measurements of the Hubble parameter -- astrophysics -- including the star-formation-rate -- and particle physics -- including the neutrino lifetime and the possibility that neutrinos are pseudo-Dirac fermions.
hep-ph/0009131
null
M. Shifman
Quark-Hadron Duality
Based on the talks delivered at the VIII-th International Symposium on Heavy Flavor Physics, Southampton, UK, 25-29 July 1999, and the International Workshop "Gribov-70", Orsay, France, 27-29 March 2000. To be published in the Boris Ioffe Festschrift "At the Frontier of Particle Physics/Handbook of QCD", Ed. M. Shifman (World Scientific, Singapore, 2001); 41 pages, 14 eps figures, Latex
null
10.1142/9789812810458_0032
TPI-MINN-00/44, UMN-TH-1920/00
hep-ph
null
I review the notion of the quark-hadron duality from the modern perspective. Both, the theoretical foundation and practical applications are discussed. The proper theoretical framework in which the problem can be formulated and treated is Wilson's operator product expansion (OPE). Two models developed for the description of duality violations are considered in some detail: one is instanton-based, another resonance-based. The mechanisms they represent are complementary. Although both models are rather primitive (their largest virtue is their simplicity) they hopefully capture important features of the phenomenon. Being open for improvements, they can be used "as is" for orientation in the studies of duality violations in the processes of practical interest.
[ { "created": "Mon, 11 Sep 2000 17:23:58 GMT", "version": "v1" } ]
2016-11-23
[ [ "Shifman", "M.", "" ] ]
I review the notion of the quark-hadron duality from the modern perspective. Both, the theoretical foundation and practical applications are discussed. The proper theoretical framework in which the problem can be formulated and treated is Wilson's operator product expansion (OPE). Two models developed for the description of duality violations are considered in some detail: one is instanton-based, another resonance-based. The mechanisms they represent are complementary. Although both models are rather primitive (their largest virtue is their simplicity) they hopefully capture important features of the phenomenon. Being open for improvements, they can be used "as is" for orientation in the studies of duality violations in the processes of practical interest.
hep-ph/9807325
Yasunori Nomura
Yasunori Nomura and T. Yanagida
Bi-Maximal Neutrino Mixing in SO(10)_{GUT}
9 pages, Latex
Phys.Rev.D59:017303,1999
10.1103/PhysRevD.59.017303
UT-823
hep-ph
null
We find a grand unified SO(10) model which accommodates the bi-maximal neutrino mixing for vacuum-oscillation solutions to the atmospheric and the solar neutrino problems. This model maintains the original SO(10) mass relation between neutrino and up-type quark masses, $m_{\nu_2} / m_{\nu_3} \sim (m_{c}/m_{t})^2$.
[ { "created": "Fri, 10 Jul 1998 08:24:31 GMT", "version": "v1" }, { "created": "Tue, 20 Oct 1998 09:28:49 GMT", "version": "v2" } ]
2009-09-29
[ [ "Nomura", "Yasunori", "" ], [ "Yanagida", "T.", "" ] ]
We find a grand unified SO(10) model which accommodates the bi-maximal neutrino mixing for vacuum-oscillation solutions to the atmospheric and the solar neutrino problems. This model maintains the original SO(10) mass relation between neutrino and up-type quark masses, $m_{\nu_2} / m_{\nu_3} \sim (m_{c}/m_{t})^2$.
1208.2021
Victo Dos Santos Filho
Clayton S. Mello, Jos\'e P. Cruz Filho, Edson O. da Silva, J. P. B. C. de Melo, Bruno El-Bennich and Victo S. Filho
Electromagnetic Structure of the Pion
Paper with 4 pages, 1 figure, presented in XII HADRON PHYSICS Conference - to appear in AIP Conference Proceedings
null
10.1063/1.4795990
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this work, we analyze the electromagnetic structure of the pion. We calculate its electromagnetic radius and electromagnetic form factor in low and intermediate momentum range. Such observables are determined by means of a theoretical model that takes into account the constituent quark and antiquark of the pion within the formalism of light-front field theory. In particular, we consider a nonsymmetrical vertex in this model, with which we calculate the electromagnetic form factor of the pion in an optimized way, so that we obtain a value closer to the experimental charge radius of the pion. The theoretical calculations are also compared with the most recent experimental data involving the pion electromagnetic form factor and the results show very good agreement.
[ { "created": "Thu, 9 Aug 2012 19:45:53 GMT", "version": "v1" }, { "created": "Wed, 20 Feb 2013 15:33:07 GMT", "version": "v2" } ]
2015-06-11
[ [ "Mello", "Clayton S.", "" ], [ "Filho", "José P. Cruz", "" ], [ "da Silva", "Edson O.", "" ], [ "de Melo", "J. P. B. C.", "" ], [ "El-Bennich", "Bruno", "" ], [ "Filho", "Victo S.", "" ] ]
In this work, we analyze the electromagnetic structure of the pion. We calculate its electromagnetic radius and electromagnetic form factor in low and intermediate momentum range. Such observables are determined by means of a theoretical model that takes into account the constituent quark and antiquark of the pion within the formalism of light-front field theory. In particular, we consider a nonsymmetrical vertex in this model, with which we calculate the electromagnetic form factor of the pion in an optimized way, so that we obtain a value closer to the experimental charge radius of the pion. The theoretical calculations are also compared with the most recent experimental data involving the pion electromagnetic form factor and the results show very good agreement.
2110.14776
Tobias Huber
Jing Gao, Tobias Huber, Yao Ji, Yu-Ming Wang
The pion-photon transition form factor at two loops in QCD
12 pages, 5 figures. Contribution to the 15th International Symposium on Radiative Corrections (RADCOR) and the XIX Workshop on Radiative Corrections for the LHC and Future Colliders (LoopFest)
null
null
SI-HEP-2021-28, P3H-21-083, TUM-HEP-1369/21
hep-ph
http://creativecommons.org/licenses/by/4.0/
We report on the fully analytic calculation of the leading-power contribution to the photon-pion transition form factor $\gamma \, \gamma^{\ast} \to \pi^0$ at two loops in QCD. The applied techniques are based on hard-collinear factorization, together with modern multi-loop methods. We focus both, on the technical details such as the treatment of evanescent operators, and the phenomenological implications. Our results indicate that the two-loop correction is numerically comparable to the one-loop effect in the same kinematic domain. We also demonstrate that our results will play a key role in disentangling various models for the twist-two pion distribution amplitude thanks to the envisaged precision at Belle II.
[ { "created": "Wed, 27 Oct 2021 21:13:09 GMT", "version": "v1" } ]
2021-10-29
[ [ "Gao", "Jing", "" ], [ "Huber", "Tobias", "" ], [ "Ji", "Yao", "" ], [ "Wang", "Yu-Ming", "" ] ]
We report on the fully analytic calculation of the leading-power contribution to the photon-pion transition form factor $\gamma \, \gamma^{\ast} \to \pi^0$ at two loops in QCD. The applied techniques are based on hard-collinear factorization, together with modern multi-loop methods. We focus both, on the technical details such as the treatment of evanescent operators, and the phenomenological implications. Our results indicate that the two-loop correction is numerically comparable to the one-loop effect in the same kinematic domain. We also demonstrate that our results will play a key role in disentangling various models for the twist-two pion distribution amplitude thanks to the envisaged precision at Belle II.
hep-ph/0105197
Xiangdong Ji
Jiunn-Wei Chen and Xiangdong Ji
Is the Sullivan Process Compatible with QCD Chiral Dynamics?
2 pages, two figures included
Phys.Lett.B523:107-110,2001
10.1016/S0370-2693(01)01337-5
null
hep-ph hep-lat nucl-th
null
We calculate the leading non-analytic quark-mass dependence in the moments of isovector quark distributions using heavy-baryon chiral perturbation theory. The results differ from those obtained from the Sullivan process in which hard scattering occurs through the virtual pion cloud of the nucleon. Our results provide useful guidance for improving upon the meson-cloud model and can be used to constrain the extrapolations of the existing lattice QCD results to the physical quark masses.
[ { "created": "Sat, 19 May 2001 04:12:44 GMT", "version": "v1" }, { "created": "Fri, 6 Jul 2001 20:06:22 GMT", "version": "v2" } ]
2008-11-26
[ [ "Chen", "Jiunn-Wei", "" ], [ "Ji", "Xiangdong", "" ] ]
We calculate the leading non-analytic quark-mass dependence in the moments of isovector quark distributions using heavy-baryon chiral perturbation theory. The results differ from those obtained from the Sullivan process in which hard scattering occurs through the virtual pion cloud of the nucleon. Our results provide useful guidance for improving upon the meson-cloud model and can be used to constrain the extrapolations of the existing lattice QCD results to the physical quark masses.
1506.04413
Jacopo Ferretti
M. De Sanctis, J. Ferretti, E. Santopinto and A. Vassallo
Relativistic quark-diquark model of baryons. Non strange spectrum and nucleon electromagnetic form factors
Talks presented at the conference "Beauty in Physics: Theory and Experiment : Meeting in honor of Francesco Iachello on the occasion of his 70th birthday", 14-18 May 2012. Cocoyoc, Mexico
AIP Conf.Proc. 1488 (2012) 280-289
10.1063/1.4759409
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We briefly describe our relativistic quark-diquark model, developed within the framework of point form dynamics, which is the relativistic extension of the interacting quark-diquark model. In order to do that we have to show the main properties and quantum numbers of the effective degree of freedom of constituent diquark. Our results for the nonstrange baryon spectrum and for the nucleon electromagnetic form factors are discussed.
[ { "created": "Sun, 14 Jun 2015 16:18:41 GMT", "version": "v1" } ]
2015-10-05
[ [ "De Sanctis", "M.", "" ], [ "Ferretti", "J.", "" ], [ "Santopinto", "E.", "" ], [ "Vassallo", "A.", "" ] ]
We briefly describe our relativistic quark-diquark model, developed within the framework of point form dynamics, which is the relativistic extension of the interacting quark-diquark model. In order to do that we have to show the main properties and quantum numbers of the effective degree of freedom of constituent diquark. Our results for the nonstrange baryon spectrum and for the nucleon electromagnetic form factors are discussed.
hep-ph/0702119
Fulvio Piccinini
Emidio Gabrielli, Fabio Maltoni, Barbara Mele, Mauro Moretti, Fulvio Piccinini, Roberto Pittau
Higgs Boson Production in Association with a Photon in Vector Boson Fusion at the LHC
30 pages, 8 figures, 8 tables; minor corrections to the text; version appeared in Nuclear Physics B
Nucl.Phys.B781:64-84,2007
10.1016/j.nuclphysb.2007.05.010
CP3-07-03, FNT/T-2007/01, HIP-2006-01/TH
hep-ph
null
Higgs boson production in association with two forward jets and a central photon at the CERN Large Hadron Collider is analyzed, for the Higgs boson decaying into a b bbar pair in the m_H <= 140 GeV mass region. We study both irreducible and main reducible backgrounds at parton level. Compared to the Higgs production via vector-boson fusion, the request of a further photon at moderate rapidities dramatically enhances the signal/background ratio. Inclusive cross sections for p_T^\gamma >= 20 GeV can reach a few tens of fb's. After a suitable choice of kinematical cuts, the cross-section ratio for signal and irreducible-background can be enhanced up to >= ~1/10, with a signal cross section of the order of a few fb's, for m_H ~ 120 GeV. The request of a central photon radiation also enhances the relative signal sensitivity to the WWH coupling with respect to the ZZH coupling. Hence, a determination of the cross section for the associated production of a Higgs boson decaying into a b bbar pair plus a central photon in vector-boson fusion could help in constraining the b bbar H coupling, and the WWH coupling as well. A preliminary study of QCD showering effects points to a further significant improvement of the signal detectability over the background.
[ { "created": "Mon, 12 Feb 2007 16:32:41 GMT", "version": "v1" }, { "created": "Wed, 29 Aug 2007 09:51:22 GMT", "version": "v2" } ]
2008-11-26
[ [ "Gabrielli", "Emidio", "" ], [ "Maltoni", "Fabio", "" ], [ "Mele", "Barbara", "" ], [ "Moretti", "Mauro", "" ], [ "Piccinini", "Fulvio", "" ], [ "Pittau", "Roberto", "" ] ]
Higgs boson production in association with two forward jets and a central photon at the CERN Large Hadron Collider is analyzed, for the Higgs boson decaying into a b bbar pair in the m_H <= 140 GeV mass region. We study both irreducible and main reducible backgrounds at parton level. Compared to the Higgs production via vector-boson fusion, the request of a further photon at moderate rapidities dramatically enhances the signal/background ratio. Inclusive cross sections for p_T^\gamma >= 20 GeV can reach a few tens of fb's. After a suitable choice of kinematical cuts, the cross-section ratio for signal and irreducible-background can be enhanced up to >= ~1/10, with a signal cross section of the order of a few fb's, for m_H ~ 120 GeV. The request of a central photon radiation also enhances the relative signal sensitivity to the WWH coupling with respect to the ZZH coupling. Hence, a determination of the cross section for the associated production of a Higgs boson decaying into a b bbar pair plus a central photon in vector-boson fusion could help in constraining the b bbar H coupling, and the WWH coupling as well. A preliminary study of QCD showering effects points to a further significant improvement of the signal detectability over the background.
hep-ph/0505054
Mats Lindroos
J.Bernabeu, J.Burguet-Castell, C.Espinoza, M.Lindroos
Monochromatic neutrino beams
null
JHEP0512:014,2005
10.1088/1126-6708/2005/12/014
null
hep-ph
null
In the last few years spectacular results have been achieved with the demonstration of non vanishing neutrino masses and flavour mixing. The ultimate goal is the understanding of the origin of these properties from new physics. In this road, the last unknown mixing [Ue3] must be determined. If it is proved to be non-zero, the possibility is open for Charge Conjugation-Parity (CP) violation in the lepton sector. This will require precision experiments with a very intense neutrino source. Here a novel method to create a monochromatic neutrino beam, an old dream for neutrino physics, is proposed based on the recent discovery of nuclei that decay fast through electron capture. Such nuclei will generate a monochromatic directional neutrino beam when decaying at high energy in a storage ring with long straight sections. We also show that the capacity of such a facility to discover new physics is impressive, so that fine tuning of the boosted neutrino energy allows precision measurements of the oscillation parameters even for a [Ue3] mixing as small as 1 degree. We can thus open a window to the discovery of CP violation in neutrino oscillations.
[ { "created": "Sat, 7 May 2005 17:13:16 GMT", "version": "v1" } ]
2009-11-11
[ [ "Bernabeu", "J.", "" ], [ "Burguet-Castell", "J.", "" ], [ "Espinoza", "C.", "" ], [ "Lindroos", "M.", "" ] ]
In the last few years spectacular results have been achieved with the demonstration of non vanishing neutrino masses and flavour mixing. The ultimate goal is the understanding of the origin of these properties from new physics. In this road, the last unknown mixing [Ue3] must be determined. If it is proved to be non-zero, the possibility is open for Charge Conjugation-Parity (CP) violation in the lepton sector. This will require precision experiments with a very intense neutrino source. Here a novel method to create a monochromatic neutrino beam, an old dream for neutrino physics, is proposed based on the recent discovery of nuclei that decay fast through electron capture. Such nuclei will generate a monochromatic directional neutrino beam when decaying at high energy in a storage ring with long straight sections. We also show that the capacity of such a facility to discover new physics is impressive, so that fine tuning of the boosted neutrino energy allows precision measurements of the oscillation parameters even for a [Ue3] mixing as small as 1 degree. We can thus open a window to the discovery of CP violation in neutrino oscillations.
2312.05853
Saraswati Pandey
Saraswati Pandey, B. K. Singh
Predicting Quadrupole deformation via anisotropic flow and transverse momentum spectra in isotopic $\mathbf{\prescript{128-135}{54}{\mathrm{Xe}}}$ collisions at LHC
10 pages, 10 figures
null
null
null
hep-ph nucl-th
http://creativecommons.org/licenses/by/4.0/
In the hydrodynamical description of heavy-ion collisions, the elliptic flow $\mathrm{v_{2}}$ and triangular flow $\mathrm{v_{3}}$ are sensitive to the quadrupole deformation $\mathrm{\beta_{2}}$ of the colliding nuclei. We produce $\mathrm{v_{2}}$ and $\mathrm{v_{3}}$ ratios qualitatively and quantitatively in most-central Xe-Xe collisions at 5.44 TeV. By employing HYDJET++ model, we study the sensitivity of anisotropic flow coefficients and mean transverse momentum to the quadrupole deformation and system-size in isotopic Xe-Xe collisions. Flow observables strongly depend on the strength of nucleon-nucleon scattering occuring in even-A and odd-A nuclei. Flow for odd-A nuclei is suppressed in comparison to flow in even-A collisions. There exists a linear inter-dependence between $\mathrm{p_{T}}$ integrated anisotropic flow and nuclear deformation. Mean transverse momentum signifies the fireball temperature in body-body and tip-tip collisions. There exists a negative linear correlation of $\mathrm{\langle p_{T} \rangle}$ with collision system-size and a positive correlation with nuclear deformation. Flow measurements in high-energy, heavy-ion collisions using isotopic collision systems, offer a new precision tool to study nuclear structure physics. Observation of nuclear structure properties like nuclear deformation in a heavy-ion collision such as this would be very interesting.
[ { "created": "Sun, 10 Dec 2023 11:11:22 GMT", "version": "v1" } ]
2023-12-12
[ [ "Pandey", "Saraswati", "" ], [ "Singh", "B. K.", "" ] ]
In the hydrodynamical description of heavy-ion collisions, the elliptic flow $\mathrm{v_{2}}$ and triangular flow $\mathrm{v_{3}}$ are sensitive to the quadrupole deformation $\mathrm{\beta_{2}}$ of the colliding nuclei. We produce $\mathrm{v_{2}}$ and $\mathrm{v_{3}}$ ratios qualitatively and quantitatively in most-central Xe-Xe collisions at 5.44 TeV. By employing HYDJET++ model, we study the sensitivity of anisotropic flow coefficients and mean transverse momentum to the quadrupole deformation and system-size in isotopic Xe-Xe collisions. Flow observables strongly depend on the strength of nucleon-nucleon scattering occuring in even-A and odd-A nuclei. Flow for odd-A nuclei is suppressed in comparison to flow in even-A collisions. There exists a linear inter-dependence between $\mathrm{p_{T}}$ integrated anisotropic flow and nuclear deformation. Mean transverse momentum signifies the fireball temperature in body-body and tip-tip collisions. There exists a negative linear correlation of $\mathrm{\langle p_{T} \rangle}$ with collision system-size and a positive correlation with nuclear deformation. Flow measurements in high-energy, heavy-ion collisions using isotopic collision systems, offer a new precision tool to study nuclear structure physics. Observation of nuclear structure properties like nuclear deformation in a heavy-ion collision such as this would be very interesting.
1404.0996
Nilanjana Kumar
Nilanjana Kumar and Stephen P. Martin
LHC search for di-Higgs decays of stoponium and other scalars in events with two photons and two bottom jets
15 pages v3:Modified cuts on photon pT's and fake photon backgrounds added
Phys. Rev. D 90, 055007 (2014)
10.1103/PhysRevD.90.055007
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the prospects for LHC discovery of a narrow resonance that decays to two Higgs bosons, using the final state of two photons and two bottom jets. Our work is motivated in part by a scenario in which two-body flavor-preserving decays of the top squark are kinematically forbidden. Stoponium, a hadronic bound state of the top squark and its anti-particle, will then form, and may have a large branching fraction into the two Higgs boson final state. We estimate the cross-section needed for a 5-sigma discovery at the 14 TeV LHC for such a narrow di-Higgs resonance, using the invariant mass distributions of the final state bottom jets and photons, as a function of the integrated luminosity. The results are also applicable to any other di-Higgs resonance produced by gluon fusion.
[ { "created": "Thu, 3 Apr 2014 16:15:38 GMT", "version": "v1" }, { "created": "Mon, 14 Apr 2014 18:12:11 GMT", "version": "v2" }, { "created": "Mon, 18 Aug 2014 18:19:29 GMT", "version": "v3" } ]
2014-09-17
[ [ "Kumar", "Nilanjana", "" ], [ "Martin", "Stephen P.", "" ] ]
We study the prospects for LHC discovery of a narrow resonance that decays to two Higgs bosons, using the final state of two photons and two bottom jets. Our work is motivated in part by a scenario in which two-body flavor-preserving decays of the top squark are kinematically forbidden. Stoponium, a hadronic bound state of the top squark and its anti-particle, will then form, and may have a large branching fraction into the two Higgs boson final state. We estimate the cross-section needed for a 5-sigma discovery at the 14 TeV LHC for such a narrow di-Higgs resonance, using the invariant mass distributions of the final state bottom jets and photons, as a function of the integrated luminosity. The results are also applicable to any other di-Higgs resonance produced by gluon fusion.
hep-ph/9907361
Bob Holdom
B. Holdom
Nonstandard order parameters and the origin of CP violation
12 pages, no figures
Phys.Rev.D61:011702,2000
10.1103/PhysRevD.61.011702
UTPT-99-12
hep-ph
null
The consideration of chirality-preserving 2-fermion order parameters may shed new light on the strong CP problem and the breakdown of flavor symmetries. We describe two situations, one having the standard KM picture for weak CP violation and another having new sources of weak CP violation.
[ { "created": "Wed, 14 Jul 1999 18:49:30 GMT", "version": "v1" } ]
2009-12-30
[ [ "Holdom", "B.", "" ] ]
The consideration of chirality-preserving 2-fermion order parameters may shed new light on the strong CP problem and the breakdown of flavor symmetries. We describe two situations, one having the standard KM picture for weak CP violation and another having new sources of weak CP violation.
0804.4401
Giuseppe Bozzi
Sara Bolognesi, Giuseppe Bozzi, Andrea Di Simone
Higgs at LHC
10 pages, 9 figures, talk given at: V Workshop Italiano sulla fisica p-p ad LHC, Perugia, Italy, 30 Jan. - 2 Feb. 2008
Nuovo Cim.B123:499-508,2008
10.1393/ncb/i2008-10537-3
KA-TP-11-2008
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
An overview of recent theoretical results on the Higgs boson and its discovery strategy at ATLAS and CMS will be presented, focusing on the main Higgs analysis effective with low integrated luminosity (less than 30 fb^-1).
[ { "created": "Mon, 28 Apr 2008 13:21:11 GMT", "version": "v1" } ]
2010-11-11
[ [ "Bolognesi", "Sara", "" ], [ "Bozzi", "Giuseppe", "" ], [ "Di Simone", "Andrea", "" ] ]
An overview of recent theoretical results on the Higgs boson and its discovery strategy at ATLAS and CMS will be presented, focusing on the main Higgs analysis effective with low integrated luminosity (less than 30 fb^-1).
1608.04911
Fredrik Bj\"orkeroth
Fredrik Bj\"orkeroth, Stephen F. King, Kai Schmitz, Tsutomu T. Yanagida
Leptogenesis after Chaotic Sneutrino Inflation and the Supersymmetry Breaking Scale
v2: 25 pages, 4 figures; version published in NPB, minor corrections. v1: 24 pages, 4 figures
null
10.1016/j.nuclphysb.2017.01.017
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We discuss resonant leptogenesis arising from the decays of two nearly-degenerate right-handed neutrinos, identified as the inflaton and stabiliser superfields in a model of chaotic sneutrino inflation. We compare an analytical estimate of the baryon asymmetry $ \eta_B $ in the Boltzmann approximation to a numerical solution of the full density matrix equations, and find that the analytical result fails to capture the correct physics in certain regions of parameter space. The observed baryon asymmetry can be realised for a breaking of the mass degeneracy as small as $ \mathcal{O}(10^{-8}) $. The origin of such a small mass splitting is explained by considering supersymmetry (SUSY) breaking in supergravity, which requires a constant in the superpotential of the order of the gravitino mass $ m_{3/2} $ to cancel the cosmological constant. This yields additional terms in the (s)neutrino mass matrices, lifting the degeneracy and linking $ \eta_B $ to the SUSY breaking scale. We find that achieving the correct baryon asymmetry requires a gravitino mass $ m_{3/2} \geq \mathcal{O}(100) $ TeV.
[ { "created": "Wed, 17 Aug 2016 09:52:15 GMT", "version": "v1" }, { "created": "Mon, 27 Feb 2017 18:34:57 GMT", "version": "v2" } ]
2017-02-28
[ [ "Björkeroth", "Fredrik", "" ], [ "King", "Stephen F.", "" ], [ "Schmitz", "Kai", "" ], [ "Yanagida", "Tsutomu T.", "" ] ]
We discuss resonant leptogenesis arising from the decays of two nearly-degenerate right-handed neutrinos, identified as the inflaton and stabiliser superfields in a model of chaotic sneutrino inflation. We compare an analytical estimate of the baryon asymmetry $ \eta_B $ in the Boltzmann approximation to a numerical solution of the full density matrix equations, and find that the analytical result fails to capture the correct physics in certain regions of parameter space. The observed baryon asymmetry can be realised for a breaking of the mass degeneracy as small as $ \mathcal{O}(10^{-8}) $. The origin of such a small mass splitting is explained by considering supersymmetry (SUSY) breaking in supergravity, which requires a constant in the superpotential of the order of the gravitino mass $ m_{3/2} $ to cancel the cosmological constant. This yields additional terms in the (s)neutrino mass matrices, lifting the degeneracy and linking $ \eta_B $ to the SUSY breaking scale. We find that achieving the correct baryon asymmetry requires a gravitino mass $ m_{3/2} \geq \mathcal{O}(100) $ TeV.
hep-ph/9711507
Ingo Schienbein
I. Schienbein
Leading log radiative corrections to polarized heavy flavour leptoproduction
22 pages, 5 figures, 1 fig. removed, 1 formula added, several additions and changes in the text and the abstract
Phys.Rev. D59 (1999) 013001
10.1103/PhysRevD.59.013001
DOTH-97/26
hep-ph
null
O(\alpha) QED radiative corrections to polarized neutral current leptoproduction of heavy quark flavours are calculated in the leading log approximation for HERMES, COMPASS, and HERA kinematics. Besides the inclusive case, we derive general $z_h$-differential formulae for the polarized boson gluon fusion process and use them to calculate radiative corrections to semi-inclusive polarized heavy flavour production in the case of HERA kinematics.
[ { "created": "Fri, 28 Nov 1997 10:52:05 GMT", "version": "v1" }, { "created": "Wed, 22 Apr 1998 09:03:59 GMT", "version": "v2" } ]
2009-10-30
[ [ "Schienbein", "I.", "" ] ]
O(\alpha) QED radiative corrections to polarized neutral current leptoproduction of heavy quark flavours are calculated in the leading log approximation for HERMES, COMPASS, and HERA kinematics. Besides the inclusive case, we derive general $z_h$-differential formulae for the polarized boson gluon fusion process and use them to calculate radiative corrections to semi-inclusive polarized heavy flavour production in the case of HERA kinematics.
hep-ph/0702135
Adrian Melissinos
Adrian C. Melissinos
Comment on "Experimental Observation of Optical Rotation Generated in Vacuum by a Magnetic Field"
3 pages, 2 figures
null
null
null
hep-ph
null
We point out that recent claims of the detection of a light pseudoscalar/scalar (axion-like) particle [1,2] are excluded at the 95% level by an earlier experiment [3].
[ { "created": "Tue, 13 Feb 2007 15:46:17 GMT", "version": "v1" } ]
2007-05-23
[ [ "Melissinos", "Adrian C.", "" ] ]
We point out that recent claims of the detection of a light pseudoscalar/scalar (axion-like) particle [1,2] are excluded at the 95% level by an earlier experiment [3].
0812.2855
Bernd-Jochen Schaefer
Bernd-Jochen Schaefer and Mathias Wagner
On the QCD phase structure from effective models
7 pages, 4 figures, talk given by BJS at the 30th International School of Nuclear Physics, "Heavy Ion Collisions from the Coulomb Barrier to the Quark Gluon Plasma", Erice, Italy, 16-24 September 2008. To appear in the proceedings
Progress in Particle and Nuclear Physics 62, 381 (2009)
10.1016/j.ppnp.2008.12.009
null
hep-ph hep-th nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Some recent theoretical developments of the QCD phase diagram are summarized. Chiral symmetry restoration and the confinement/deconfinement transition at nonzero temperature and quark densities are analyzed in the framework of an effective linear sigma model with three light quark flavors. The sensitivity of the chiral transition as well as the existence of a critical end point in the phase diagram on the value of the sigma mass is explored. The influence of the axial anomaly on the chiral critical surface is addressed. Finally, the modifications by the inclusion of the Polyakov loop on the phase structure are investigated.
[ { "created": "Mon, 15 Dec 2008 16:30:34 GMT", "version": "v1" } ]
2012-11-08
[ [ "Schaefer", "Bernd-Jochen", "" ], [ "Wagner", "Mathias", "" ] ]
Some recent theoretical developments of the QCD phase diagram are summarized. Chiral symmetry restoration and the confinement/deconfinement transition at nonzero temperature and quark densities are analyzed in the framework of an effective linear sigma model with three light quark flavors. The sensitivity of the chiral transition as well as the existence of a critical end point in the phase diagram on the value of the sigma mass is explored. The influence of the axial anomaly on the chiral critical surface is addressed. Finally, the modifications by the inclusion of the Polyakov loop on the phase structure are investigated.
hep-ph/9809452
Stephane Bronoff groupe
S. Bronoff, R. Buffa, C.P. Korthals Altes
Phase diagram of 3D SU(3) gauge-adjoint Higgs system
Contributing paper to the proceedings of the 5th International Workshop on Thermal Field Theories and their Applications, Regensburg, Germany, August 10-14, 1998. Corrected typos, changes in wording
null
null
null
hep-ph
null
Thermally reduced QCD leads to three dimensional SU(3) gaugefields coupled to an adjoint scalar field $A_0$. We compute the effective potential in the one-loop approximation and evaluate the VEV's of $TrA_0^2$ and $TrA_0^3$. In the Higgs phase not only the former, but also the latter has a VEV. This happens where the SU(3) gauge symmetry is broken minimally with U(2) still unbroken. It is plausible that in the Higgs phase one has a transition for large enough Higgs selfcoupling to a region where $TrA_0^3$ has no VEV and where the gaugesymmetry is broken maximally to $U(1)\times U(1)$.
[ { "created": "Fri, 18 Sep 1998 16:28:58 GMT", "version": "v1" }, { "created": "Thu, 8 Oct 1998 11:51:15 GMT", "version": "v2" }, { "created": "Wed, 14 Oct 1998 09:07:47 GMT", "version": "v3" } ]
2007-05-23
[ [ "Bronoff", "S.", "" ], [ "Buffa", "R.", "" ], [ "Altes", "C. P. Korthals", "" ] ]
Thermally reduced QCD leads to three dimensional SU(3) gaugefields coupled to an adjoint scalar field $A_0$. We compute the effective potential in the one-loop approximation and evaluate the VEV's of $TrA_0^2$ and $TrA_0^3$. In the Higgs phase not only the former, but also the latter has a VEV. This happens where the SU(3) gauge symmetry is broken minimally with U(2) still unbroken. It is plausible that in the Higgs phase one has a transition for large enough Higgs selfcoupling to a region where $TrA_0^3$ has no VEV and where the gaugesymmetry is broken maximally to $U(1)\times U(1)$.
2110.09186
Marco Danilo Claudio Torri
Marco Danilo Claudio Torri
Neutrino Oscillations and Lorentz Invariance Violation
null
Universe 6 (2020) 3, 37
10.3390/universe6030037
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This work explores the possibility of resorting to neutrino phenomenology to detect evidence of new physics, caused by the residual signals of the supposed quantum structure of spacetime. In particular, this work investigates the effects on neutrino oscillations and mass hierarchy detection, predicted by models that violate Lorentz invariance, preserving the spacetime isotropy and homogeneity. Neutrino physics is the ideal environment where conducting the search for new "exotic" physics, since the oscillation phenomenon is not included in the original formulation of the minimal Standard Model (SM) of particles. The confirmed observation of the neutrino oscillation phenomenon is, therefore, the first example of physics beyond the SM and can indicate the necessity to resort to new theoretical models. In this work, the hypothesis that the supposed Lorentz Invariance Violation (LIV) perturbations can influence the oscillation pattern is investigated. LIV theories are indeed constructed assuming modified kinematics, caused by the interaction of massive particles with the spacetime background. This means that the dispersion relations are modified, so it appears natural to search for effects caused by LIV in physical phenomena governed by masses, as in the case of neutrino oscillations. In addition, the neutrino oscillation phenomenon is interesting since there are three different mass eigenstates and in a LIV scenario, which preserves isotropy, at least two different species of particle must interact.
[ { "created": "Mon, 18 Oct 2021 11:03:35 GMT", "version": "v1" } ]
2021-10-19
[ [ "Torri", "Marco Danilo Claudio", "" ] ]
This work explores the possibility of resorting to neutrino phenomenology to detect evidence of new physics, caused by the residual signals of the supposed quantum structure of spacetime. In particular, this work investigates the effects on neutrino oscillations and mass hierarchy detection, predicted by models that violate Lorentz invariance, preserving the spacetime isotropy and homogeneity. Neutrino physics is the ideal environment where conducting the search for new "exotic" physics, since the oscillation phenomenon is not included in the original formulation of the minimal Standard Model (SM) of particles. The confirmed observation of the neutrino oscillation phenomenon is, therefore, the first example of physics beyond the SM and can indicate the necessity to resort to new theoretical models. In this work, the hypothesis that the supposed Lorentz Invariance Violation (LIV) perturbations can influence the oscillation pattern is investigated. LIV theories are indeed constructed assuming modified kinematics, caused by the interaction of massive particles with the spacetime background. This means that the dispersion relations are modified, so it appears natural to search for effects caused by LIV in physical phenomena governed by masses, as in the case of neutrino oscillations. In addition, the neutrino oscillation phenomenon is interesting since there are three different mass eigenstates and in a LIV scenario, which preserves isotropy, at least two different species of particle must interact.
1101.3623
Hideko Nagahiro
H. Nagahiro, K. Nawa, S. Ozaki, D. Jido and A. Hosaka
Composite and elementary natures of a1(1260) meson
13 pages, 4 figures
Phys.Rev.D83:111504,2011
10.1103/PhysRevD.83.111504
YITP-11-13
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We develop a practical method to analyze the mixing structure of hadrons consisting of two components of quark-composite and hadronic composite. As an example we investigate the properties of the axial vector meson a1(1260) and discuss its mixing properties quantitatively. We also make reference to the large Nc procedure and its limitation for the classification of such a mixed state.
[ { "created": "Wed, 19 Jan 2011 06:41:54 GMT", "version": "v1" }, { "created": "Thu, 12 May 2011 08:38:47 GMT", "version": "v2" } ]
2015-03-17
[ [ "Nagahiro", "H.", "" ], [ "Nawa", "K.", "" ], [ "Ozaki", "S.", "" ], [ "Jido", "D.", "" ], [ "Hosaka", "A.", "" ] ]
We develop a practical method to analyze the mixing structure of hadrons consisting of two components of quark-composite and hadronic composite. As an example we investigate the properties of the axial vector meson a1(1260) and discuss its mixing properties quantitatively. We also make reference to the large Nc procedure and its limitation for the classification of such a mixed state.
hep-ph/9702284
Lubov Vassilevskaya
N.V. Mikheev and L.A. Vassilevskaya
Electromagnetic Catalysis of the Radiative Decay of the Axion
Minor revision, references added, to be published in Phys.Lett.B
Phys.Lett. B410 (1997) 207-210
10.1016/S0370-2693(97)00877-0
YARU-HE-97/01
hep-ph
null
The radiative decay of the axion $a \to \gamma \gamma$ is investigated in an external electromagnetic field in DFSZ model in which axion couples to both quarks and leptons at tree level. The decay probability is strongly catalyzed by the external field, namely, the field removes the main suppression caused by the smallness of the axion mass.
[ { "created": "Fri, 7 Feb 1997 16:16:48 GMT", "version": "v1" }, { "created": "Fri, 1 Aug 1997 12:11:26 GMT", "version": "v2" } ]
2009-10-30
[ [ "Mikheev", "N. V.", "" ], [ "Vassilevskaya", "L. A.", "" ] ]
The radiative decay of the axion $a \to \gamma \gamma$ is investigated in an external electromagnetic field in DFSZ model in which axion couples to both quarks and leptons at tree level. The decay probability is strongly catalyzed by the external field, namely, the field removes the main suppression caused by the smallness of the axion mass.
0901.4749
Rong Li
Chao-Hsi Chang, Rong Li and Jian-Xiong Wang
J/\psi polarization in photo-production up-to the next-to-leading order of QCD
5 pages, 3 figures. Discussion on the theoretical uncertainties from the choice of renormalization scale was added
Phys.Rev.D80:034020,2009
10.1103/PhysRevD.80.034020
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate the J/psi polarization in photoproduction at the Hadron Electron Ring Accelerator(HERA) up to the next-to-leading order of QCD. The results show that the transverse momentum p_t and energy fraction z distributions of J/psi production do not agree with the observed ones very well. The theoretical uncertainties for the z distributions of the J/psi polarization parameters with respect to various choices of the renormalization and factorization scales are too large to give an accurate prediction. The uncertainties for the p_t distributions of these parameters are small when p_t>3GeV and the obtained p_t distributions can not describe the experimental data even in this region.
[ { "created": "Thu, 29 Jan 2009 19:10:59 GMT", "version": "v1" }, { "created": "Mon, 2 Feb 2009 17:18:09 GMT", "version": "v2" }, { "created": "Fri, 2 Oct 2009 15:34:33 GMT", "version": "v3" } ]
2009-10-13
[ [ "Chang", "Chao-Hsi", "" ], [ "Li", "Rong", "" ], [ "Wang", "Jian-Xiong", "" ] ]
We investigate the J/psi polarization in photoproduction at the Hadron Electron Ring Accelerator(HERA) up to the next-to-leading order of QCD. The results show that the transverse momentum p_t and energy fraction z distributions of J/psi production do not agree with the observed ones very well. The theoretical uncertainties for the z distributions of the J/psi polarization parameters with respect to various choices of the renormalization and factorization scales are too large to give an accurate prediction. The uncertainties for the p_t distributions of these parameters are small when p_t>3GeV and the obtained p_t distributions can not describe the experimental data even in this region.
2105.02143
Lei Wang
Lei Wang
Inflation, electroweak phase transition, and Higgs searches at the LHC in the two-Higgs-doublet model
Some discussions are added. Matches version published in JHEP
JHEP 07 (2022) 055
10.1007/JHEP07(2022)055
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
Combining the electroweak phase transition and the Higgs searches at the LHC, we study the Higgs inflation in the type-I and type-II two-Higgs-doublet models with non-minimally couplings to gravity. Considering relevant theoretical and experimental constraints, we find that the Higgs inflation imposes stringent constraints on the mass splitting between $A$, $H^\pm$ and $H$, and they tend to be nearly degenerate in mass with increasing of their masses. The direct searches for Higgs at the LHC can exclude many points achieving Higgs inflation in the region of $m_H~(m_A)<$ 450 GeV in the type-I model, and impose a lower bound on $\tan\beta$ for the type-II model. The Higgs inflation disfavors the wrong sign Yukawa coupling region of type-II model. In the parameter space achieving the Higgs inflation, the type-I and type-II models can produce a first order electroweak phase transition, but $v_c/T_c$ is much smaller than 1.0.
[ { "created": "Wed, 5 May 2021 15:50:14 GMT", "version": "v1" }, { "created": "Mon, 10 Apr 2023 14:50:42 GMT", "version": "v2" } ]
2023-04-19
[ [ "Wang", "Lei", "" ] ]
Combining the electroweak phase transition and the Higgs searches at the LHC, we study the Higgs inflation in the type-I and type-II two-Higgs-doublet models with non-minimally couplings to gravity. Considering relevant theoretical and experimental constraints, we find that the Higgs inflation imposes stringent constraints on the mass splitting between $A$, $H^\pm$ and $H$, and they tend to be nearly degenerate in mass with increasing of their masses. The direct searches for Higgs at the LHC can exclude many points achieving Higgs inflation in the region of $m_H~(m_A)<$ 450 GeV in the type-I model, and impose a lower bound on $\tan\beta$ for the type-II model. The Higgs inflation disfavors the wrong sign Yukawa coupling region of type-II model. In the parameter space achieving the Higgs inflation, the type-I and type-II models can produce a first order electroweak phase transition, but $v_c/T_c$ is much smaller than 1.0.
hep-ph/0106306
Alberto Accardi
A. Accardi, D. Treleani (Trieste U.)
Minijet transverse spectrum in high-energy hadron-nucleus collisions
30 pages, 4 figures
Phys.Rev. D64 (2001) 116004
10.1103/PhysRevD.64.116004
null
hep-ph
null
Hadron-nucleus collisions at LHC energies are studied by including explicitly semi-hard parton rescatterings in the collision dynamics. Under rather general conditions, we obtain explicit formulae for the semi-hard cross-section and the inclusive minijet transverse spectrum. As an effect of the rescatterings the spectrum is lowered at small $p_t$ and is enhanced at relatively large transverse momenta, the deformation being more pronounced at increasing rapidity. Its study allows to test the proposed interaction mechanisms and represents an important baseline to examine nucleus-nucleus collisions.
[ { "created": "Wed, 27 Jun 2001 14:34:58 GMT", "version": "v1" } ]
2009-11-07
[ [ "Accardi", "A.", "", "Trieste U." ], [ "Treleani", "D.", "", "Trieste U." ] ]
Hadron-nucleus collisions at LHC energies are studied by including explicitly semi-hard parton rescatterings in the collision dynamics. Under rather general conditions, we obtain explicit formulae for the semi-hard cross-section and the inclusive minijet transverse spectrum. As an effect of the rescatterings the spectrum is lowered at small $p_t$ and is enhanced at relatively large transverse momenta, the deformation being more pronounced at increasing rapidity. Its study allows to test the proposed interaction mechanisms and represents an important baseline to examine nucleus-nucleus collisions.
hep-ph/9804416
Enrico Franco
U. Aglietti, M. Ciuchini, G. Corbo', E. Franco, G. Martinelli, L. Silvestrini
Model independent determination of the shape function for inclusive B decays and of the structure functions in DIS
16 pages, LaTeX file
Phys.Lett. B432 (1998) 411-420
10.1016/S0370-2693(98)00677-7
ROME1-1208/98, TUM-HEP-309/98
hep-ph
null
We present a method to compute, by numerical simulations of lattice QCD, the inclusive semileptonic differential decay rates of heavy hadrons and the structure functions which occur in deep inelastic scattering. The method is based on first principles and does not require any model assumption. It allows the prediction of the differential rate in B semileptonic decays for values of the recoiling hadronic mass W ~ sqrt(M_B Lambda_QCD), which is in the relevant region to extract |V_ub| from the end-point of the lepton spectrum in inclusive decays.
[ { "created": "Mon, 27 Apr 1998 13:50:51 GMT", "version": "v1" } ]
2009-10-31
[ [ "Aglietti", "U.", "" ], [ "Ciuchini", "M.", "" ], [ "Corbo'", "G.", "" ], [ "Franco", "E.", "" ], [ "Martinelli", "G.", "" ], [ "Silvestrini", "L.", "" ] ]
We present a method to compute, by numerical simulations of lattice QCD, the inclusive semileptonic differential decay rates of heavy hadrons and the structure functions which occur in deep inelastic scattering. The method is based on first principles and does not require any model assumption. It allows the prediction of the differential rate in B semileptonic decays for values of the recoiling hadronic mass W ~ sqrt(M_B Lambda_QCD), which is in the relevant region to extract |V_ub| from the end-point of the lepton spectrum in inclusive decays.
2403.16061
Parada Hutauruk T. P.
Parada T. P. Hutauruk
Nonstandard interactions of neutrinos with dense matter
14 pages, 8 figures, 1 table
null
null
PKNU-NuHaTh-2024
hep-ph astro-ph.HE astro-ph.SR hep-ex nucl-th
http://creativecommons.org/licenses/by/4.0/
Nonstandard interaction is expected to be a crucial hint to explain the experimental data of neutrino scattering off electrons. In this context, the nonstandard interaction vector and axial-vector couplings are needed to be extracted from recent experiments and a few of them are now available in the literature. With these coupling bounds, in this paper, I explore their impacts on the neutrinos interacting with the free electron gas in dense matter. To this end, I compute and predict the neutrino differential cross section and mean free path in dense matter for all those experimental bounds. Interesting behavior in the neutrino cross sections and mean free path is found for the different nonstandard interaction couplings from different experiment constraints. I also found that the neutrino cross-section and mean free path in the dense matter are very sensitive to values and signs of the nonstandard interaction couplings, leading to different prediction results to the Standard Model cross-section and mean free path.
[ { "created": "Sun, 24 Mar 2024 08:12:32 GMT", "version": "v1" } ]
2024-03-26
[ [ "Hutauruk", "Parada T. P.", "" ] ]
Nonstandard interaction is expected to be a crucial hint to explain the experimental data of neutrino scattering off electrons. In this context, the nonstandard interaction vector and axial-vector couplings are needed to be extracted from recent experiments and a few of them are now available in the literature. With these coupling bounds, in this paper, I explore their impacts on the neutrinos interacting with the free electron gas in dense matter. To this end, I compute and predict the neutrino differential cross section and mean free path in dense matter for all those experimental bounds. Interesting behavior in the neutrino cross sections and mean free path is found for the different nonstandard interaction couplings from different experiment constraints. I also found that the neutrino cross-section and mean free path in the dense matter are very sensitive to values and signs of the nonstandard interaction couplings, leading to different prediction results to the Standard Model cross-section and mean free path.
hep-ph/9406325
null
Stefano Catani
Low-x Structure Functions
19 pages (+ 9 figs. available in hard copy upon request to catani@fi.infn.it), LaTeX, DFF 207/6/94
null
null
null
hep-ph
null
QCD predictions on the low-$x$ behaviour of the structure functions are reviewed and compared with the recent measurements of $F_2(x,Q^2)$ at HERA. The present theoretical accuracy of these predictions is discussed.
[ { "created": "Thu, 16 Jun 1994 10:10:20 GMT", "version": "v1" } ]
2009-09-25
[ [ "Catani", "Stefano", "" ] ]
QCD predictions on the low-$x$ behaviour of the structure functions are reviewed and compared with the recent measurements of $F_2(x,Q^2)$ at HERA. The present theoretical accuracy of these predictions is discussed.
2107.10866
Fulvia De Fazio
Andrzej J. Buras, Pietro Colangelo, Fulvia De Fazio, Francesco Loparco
The charm of 331
LaTeX, 31 pages, 13 figures
null
null
AJB-21-4; BARI-TH/21-729
hep-ph hep-ex hep-lat
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We perform a detailed analysis of flavour changing neutral current processes in the charm sector in the context of 331 models. As pointed out recently, in the case of $Z^\prime$ contributions in these models there are no new free parameters beyond those already present in the $B_{d,s}$ and $K$ meson systems analyzed in the past. As a result, definite ranges for new Physics (NP) effects in various charm observables could be obtained. While generally NP effects turn out to be small, in a number of observables they are much larger than the tiny effects predicted within the Standard Model. In particular we find that the branching ratio of the mode $D^0 \to \mu^+ \mu^-$, despite remaining tiny, can be enhanced by 6 orders of magnitude with respect to the SM. We work out correlations between this mode and rare $B_{d,s}$ and $K$ decays. We also discuss neutral charm meson oscillations and CP violation in the charm system. In particular, we point out that 331 models provide new weak phases that are a necessary condition to have non-vanishing CP asymmetries. In the case of $\Delta A_{CP}$, the difference between the CP asymmetries in $D^0 \to K^+ K^-$ and $D^0 \to \pi^+ \pi^-$, we find that agreement with experiment can be obtained provided that two conditions are verified: the phases in the ranges predicted in 331 models and large hadronic matrix elements.
[ { "created": "Thu, 22 Jul 2021 18:05:56 GMT", "version": "v1" } ]
2021-07-26
[ [ "Buras", "Andrzej J.", "" ], [ "Colangelo", "Pietro", "" ], [ "De Fazio", "Fulvia", "" ], [ "Loparco", "Francesco", "" ] ]
We perform a detailed analysis of flavour changing neutral current processes in the charm sector in the context of 331 models. As pointed out recently, in the case of $Z^\prime$ contributions in these models there are no new free parameters beyond those already present in the $B_{d,s}$ and $K$ meson systems analyzed in the past. As a result, definite ranges for new Physics (NP) effects in various charm observables could be obtained. While generally NP effects turn out to be small, in a number of observables they are much larger than the tiny effects predicted within the Standard Model. In particular we find that the branching ratio of the mode $D^0 \to \mu^+ \mu^-$, despite remaining tiny, can be enhanced by 6 orders of magnitude with respect to the SM. We work out correlations between this mode and rare $B_{d,s}$ and $K$ decays. We also discuss neutral charm meson oscillations and CP violation in the charm system. In particular, we point out that 331 models provide new weak phases that are a necessary condition to have non-vanishing CP asymmetries. In the case of $\Delta A_{CP}$, the difference between the CP asymmetries in $D^0 \to K^+ K^-$ and $D^0 \to \pi^+ \pi^-$, we find that agreement with experiment can be obtained provided that two conditions are verified: the phases in the ranges predicted in 331 models and large hadronic matrix elements.
0907.2575
Bronislav Zakharov
B.G. Zakharov
Synchrotron-like gluon emission in the quark-gluon plasma
Contributed to 44th Rencontres de Moriond QCD and High Energy Interactions, La Thuile, Italy, 14-21 Mar 2009
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A quasiclassical theory of the synchrotron-like gluon emission is discussed. We show that the synchrotron emission may be important in the jet quenching if the plasma instabilities generate a chromomagnetic field about $m^{2}_{D}/g$. Our gluon spectrum disagrees with that obtained by Shuryak and Zahed within Schwinger's proper time method.
[ { "created": "Wed, 15 Jul 2009 13:00:27 GMT", "version": "v1" } ]
2009-07-16
[ [ "Zakharov", "B. G.", "" ] ]
A quasiclassical theory of the synchrotron-like gluon emission is discussed. We show that the synchrotron emission may be important in the jet quenching if the plasma instabilities generate a chromomagnetic field about $m^{2}_{D}/g$. Our gluon spectrum disagrees with that obtained by Shuryak and Zahed within Schwinger's proper time method.
hep-ph/0401015
Alexander Pankov
A.A. Pankov (Tech. Univ. of Gomel)
Model-independent analysis of four-fermion contact interaction at e^+e^- collider
10 pages with 6 figures and 1 table Presented at the 12th International Seminar on High Energy physics "Quarks-2002", Novgorod, Russia, June 1 -- 7, 2002
null
null
null
hep-ph
null
We study electron-electron contact-interaction searches in the process e^+e^-\to e^+e^- at a future e^+e^- Linear Collider with both beams longitudinally polarized. We evaluate the model-independent constraints on the coupling constants, emphasizing the role of beam polarization, and make a comparison with the case of e^+e^-\to\mu^+\mu^-.
[ { "created": "Mon, 5 Jan 2004 12:48:32 GMT", "version": "v1" } ]
2007-05-23
[ [ "Pankov", "A. A.", "", "Tech. Univ. of Gomel" ] ]
We study electron-electron contact-interaction searches in the process e^+e^-\to e^+e^- at a future e^+e^- Linear Collider with both beams longitudinally polarized. We evaluate the model-independent constraints on the coupling constants, emphasizing the role of beam polarization, and make a comparison with the case of e^+e^-\to\mu^+\mu^-.
1902.03071
Cristian Pisano
Cristian Pisano, Umberto D'Alesio, Carlo Flore, Francesco Murgia, Pieter Taels
Process dependence of the gluon Sivers function in inclusive $pp$ collisions: theory
7 pages, 2 figures; to appear in the Proceedings of the 23rd International SPIN Symposium (SPIN 2018), Ferrara (Italy), 10-14 September 2018
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Within the color gauge invariant generalized parton model (CGI-GPM), which includes initial and final state interactions in a transverse momentum dependent formalism, we present the complete results, at leading order in perturbative QCD, for transverse single-spin asymmetries in the inclusive hadroproduction of $J/\psi$ and $D$ mesons, pions and direct photons.
[ { "created": "Fri, 8 Feb 2019 13:22:08 GMT", "version": "v1" } ]
2019-02-11
[ [ "Pisano", "Cristian", "" ], [ "D'Alesio", "Umberto", "" ], [ "Flore", "Carlo", "" ], [ "Murgia", "Francesco", "" ], [ "Taels", "Pieter", "" ] ]
Within the color gauge invariant generalized parton model (CGI-GPM), which includes initial and final state interactions in a transverse momentum dependent formalism, we present the complete results, at leading order in perturbative QCD, for transverse single-spin asymmetries in the inclusive hadroproduction of $J/\psi$ and $D$ mesons, pions and direct photons.
1209.1348
Michael Gronau
Michael Gronau and Jonathan L. Rosner
Revisiting D0-D0bar mixing using U-spin
corrected fonts for {\cal B}
null
10.1103/PhysRevD.86.114029
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We prove that $D^0$-$\bar D^0$ mixing in the standard model occurs only at second order in U-spin breaking. The U-spin subgroup of SU(3) is found to be a powerful tool for analyzing the cancellation of intermediate-state contributions to the $D^0$--$\od^0$ mixing parameter $y = \Delta \Gamma/(2 \Gamma)$. Cancellations due to states {\it within a single U-spin triplet} are shown to be valid to first order in U-spin breaking. Illustrations are given for triplets consisting of (a) pairs of charged pions and kaons; (b) pairs of neutral pseudoscalar members of the meson octet; (c) charged vector-pseudoscalar pairs, and (d) states of four charged kaons and pions.
[ { "created": "Thu, 6 Sep 2012 17:35:43 GMT", "version": "v1" }, { "created": "Thu, 20 Sep 2012 16:10:57 GMT", "version": "v2" }, { "created": "Mon, 24 Sep 2012 14:30:54 GMT", "version": "v3" } ]
2013-05-30
[ [ "Gronau", "Michael", "" ], [ "Rosner", "Jonathan L.", "" ] ]
We prove that $D^0$-$\bar D^0$ mixing in the standard model occurs only at second order in U-spin breaking. The U-spin subgroup of SU(3) is found to be a powerful tool for analyzing the cancellation of intermediate-state contributions to the $D^0$--$\od^0$ mixing parameter $y = \Delta \Gamma/(2 \Gamma)$. Cancellations due to states {\it within a single U-spin triplet} are shown to be valid to first order in U-spin breaking. Illustrations are given for triplets consisting of (a) pairs of charged pions and kaons; (b) pairs of neutral pseudoscalar members of the meson octet; (c) charged vector-pseudoscalar pairs, and (d) states of four charged kaons and pions.
1507.06315
David Farhi
David Farhi, Ilya Feige, Marat Freytsis, Matthew D. Schwartz
Streamlining resummed QCD calculations using Monte Carlo integration
30 pages, 10 figures, code included with submission
null
10.1007/JHEP08(2016)112
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Some of the most arduous and error-prone aspects of precision resummed calculations are related to the partonic hard process, having nothing to do with the resummation. In particular, interfacing to parton-distribution functions, combining various channels, and performing the phase space integration can be limiting factors in completing calculations. Conveniently, however, most of these tasks are already automated in many Monte Carlo programs, such as MadGraph, Alpgen or Sherpa. In this paper, we show how such programs can be used to produce distributions of partonic kinematics with associated color structures representing the hard factor in a resummed distribution. These distributions can then be used to weight convolutions of jet, soft and beam functions producing a complete resummed calculation. In fact, only around 1000 unweighted events are necessary to produce precise distributions. A number of examples and checks are provided, including $e^+e^-$ two- and four-jet event shapes, $n$-jettiness and jet-mass related observables at hadron colliders. Attached code can be used to modify MadGraph to export the relevant leading-order hard functions and color structures for arbitrary processes.
[ { "created": "Wed, 22 Jul 2015 20:00:49 GMT", "version": "v1" } ]
2016-09-21
[ [ "Farhi", "David", "" ], [ "Feige", "Ilya", "" ], [ "Freytsis", "Marat", "" ], [ "Schwartz", "Matthew D.", "" ] ]
Some of the most arduous and error-prone aspects of precision resummed calculations are related to the partonic hard process, having nothing to do with the resummation. In particular, interfacing to parton-distribution functions, combining various channels, and performing the phase space integration can be limiting factors in completing calculations. Conveniently, however, most of these tasks are already automated in many Monte Carlo programs, such as MadGraph, Alpgen or Sherpa. In this paper, we show how such programs can be used to produce distributions of partonic kinematics with associated color structures representing the hard factor in a resummed distribution. These distributions can then be used to weight convolutions of jet, soft and beam functions producing a complete resummed calculation. In fact, only around 1000 unweighted events are necessary to produce precise distributions. A number of examples and checks are provided, including $e^+e^-$ two- and four-jet event shapes, $n$-jettiness and jet-mass related observables at hadron colliders. Attached code can be used to modify MadGraph to export the relevant leading-order hard functions and color structures for arbitrary processes.
1101.5525
He Zhang
Werner Rodejohann, He Zhang
Extended Empirical Fermion Mass Relation
6 pages, 6 figures
Phys.Lett.B698:152-156,2011
10.1016/j.physletb.2011.03.007
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It is known that the charged lepton masses obey to high precision an interesting empirical relation (Koide relation). In turn, the light neutrino masses cannot obey such a relation. We note that if neutrinos acquire their mass via the seesaw mechanism, the empirical mass relation could hold for the masses in the Dirac and/or heavy Majorana mass matrix. Examples for the phenomenological consequences are provided. We furthermore modify the mass relation for light neutrino masses including their Majorana phases, and show that it can be fulfilled in this case as well, with interesting predictions for neutrinoless double beta decay. Finally, we remark that while the relation does not hold for the up- and down-quarks, it may be valid for the u, d, s quarks, and for the c, b, t quarks.
[ { "created": "Fri, 28 Jan 2011 12:20:42 GMT", "version": "v1" } ]
2011-07-26
[ [ "Rodejohann", "Werner", "" ], [ "Zhang", "He", "" ] ]
It is known that the charged lepton masses obey to high precision an interesting empirical relation (Koide relation). In turn, the light neutrino masses cannot obey such a relation. We note that if neutrinos acquire their mass via the seesaw mechanism, the empirical mass relation could hold for the masses in the Dirac and/or heavy Majorana mass matrix. Examples for the phenomenological consequences are provided. We furthermore modify the mass relation for light neutrino masses including their Majorana phases, and show that it can be fulfilled in this case as well, with interesting predictions for neutrinoless double beta decay. Finally, we remark that while the relation does not hold for the up- and down-quarks, it may be valid for the u, d, s quarks, and for the c, b, t quarks.
0910.2071
Gagik Yeghiyan
Gagik K. Yeghiyan
Upsilon Decays into Scalar Dark Matter
6 pages, 4 figures, to be published in the proceedings of DPF-2009, Detroit, MI, July 2009, eConf C090726
null
null
WSU-HEP-0906
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We examine decays of a spin-1 bottomonium into a pair of light scalar Dark Matter (DM) particles, assuming that Dark Matter is produced due to exchange of heavy degrees of freedom. We perform a model-independent analysis and derive formulae for the branching ratios of these decays. We confront our calculation results with the experimental data. We show that Dark Matter production in Upsilon decays may lead to constraints on parameters of the models containing a light spin-0 DM particle.
[ { "created": "Mon, 12 Oct 2009 03:04:27 GMT", "version": "v1" } ]
2009-10-13
[ [ "Yeghiyan", "Gagik K.", "" ] ]
We examine decays of a spin-1 bottomonium into a pair of light scalar Dark Matter (DM) particles, assuming that Dark Matter is produced due to exchange of heavy degrees of freedom. We perform a model-independent analysis and derive formulae for the branching ratios of these decays. We confront our calculation results with the experimental data. We show that Dark Matter production in Upsilon decays may lead to constraints on parameters of the models containing a light spin-0 DM particle.
2007.14939
Kirill Tuchin
Kirill Tuchin
Photon radiation from quark-gluon plasma by means of chiral anomalies without magnetic field
contribution to the "10th International Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collisions"
null
null
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We discuss a new channel of photon emission from the quark-gluon plasma, which opens up as photon acquires a tachyonic mass in the presence of the CP-odd topological domains generated by the chiral anomaly. It allows photon radiation through the decay $q\to q\gamma$ and annihilation $q\bar q\to \gamma$ processes closely related to the chiral Cherenkov radiation. Unlike previous proposals this mechanism does not require an external magnetic field. The differential photon emission rate per unit volume is computed and shown to be comparable to the rate of photon emission in conventional processes.
[ { "created": "Wed, 29 Jul 2020 16:29:10 GMT", "version": "v1" } ]
2020-07-30
[ [ "Tuchin", "Kirill", "" ] ]
We discuss a new channel of photon emission from the quark-gluon plasma, which opens up as photon acquires a tachyonic mass in the presence of the CP-odd topological domains generated by the chiral anomaly. It allows photon radiation through the decay $q\to q\gamma$ and annihilation $q\bar q\to \gamma$ processes closely related to the chiral Cherenkov radiation. Unlike previous proposals this mechanism does not require an external magnetic field. The differential photon emission rate per unit volume is computed and shown to be comparable to the rate of photon emission in conventional processes.
hep-ph/9501384
Ulf Meissner
V. Bernard, N. Kaiser and Ulf-G. Mei{\ss}ner
Chiral Dynamics in Nucleons and Nuclei
154 pp, plain TeX, uses epsf macros, figures appended in figrev.uu (as compressed uuencoded tar files), complete PS file available from meissner@pythia.itkp.uni-bonn.de
Int.J.Mod.Phys. E4 (1995) 193-346
10.1142/S0218301395000092
CRN 95-3 and TK 95 1
hep-ph nucl-th
null
We review the implications of the spontaneous chiral symmetry breaking in QCD for processes involving one, two or more nucleons.
[ { "created": "Thu, 26 Jan 1995 12:54:43 GMT", "version": "v1" } ]
2015-06-25
[ [ "Bernard", "V.", "" ], [ "Kaiser", "N.", "" ], [ "Meißner", "Ulf-G.", "" ] ]
We review the implications of the spontaneous chiral symmetry breaking in QCD for processes involving one, two or more nucleons.
1609.04917
T. Lappi
T. Lappi
Theory overview of Heavy Ion collisions
18 pages, 14 figures, presented at the Fourth Annual Large Hadron Collider Physics Conference (LHCP2016), 13--18 June 2016, Lund, Sweden
PoS(LHCP2016)016
null
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This presentation discusses some recently active topics in the theoretical interpretation of high energy heavy ion collisions at the LHC and at RHIC. We argue that the standard paradigm for understanding the spacetime evolution of the bulk of the matter produced in the collision is provided by viscous relativistic hydrodynamics, which can be used to systematically extract properties of the QCD medium from experimental results. The initial conditions of this hydrodynamical evolution are increasingly well understood in terms of gluon saturation, and can be quantified using Classical Yang-Mills fields and QCD effective kinetic theory. Hard and electromagnetic probes of the plasma provide additional constraints. A particularly fascinating subject are high multiplicity proton-proton and proton-nucleus collisions, where some of the characteristics previously attributed to only nucleus-nucleus collisions have been observed.
[ { "created": "Fri, 16 Sep 2016 06:44:13 GMT", "version": "v1" } ]
2016-09-20
[ [ "Lappi", "T.", "" ] ]
This presentation discusses some recently active topics in the theoretical interpretation of high energy heavy ion collisions at the LHC and at RHIC. We argue that the standard paradigm for understanding the spacetime evolution of the bulk of the matter produced in the collision is provided by viscous relativistic hydrodynamics, which can be used to systematically extract properties of the QCD medium from experimental results. The initial conditions of this hydrodynamical evolution are increasingly well understood in terms of gluon saturation, and can be quantified using Classical Yang-Mills fields and QCD effective kinetic theory. Hard and electromagnetic probes of the plasma provide additional constraints. A particularly fascinating subject are high multiplicity proton-proton and proton-nucleus collisions, where some of the characteristics previously attributed to only nucleus-nucleus collisions have been observed.
0704.0031
Valery M. Biryukov
V. M. Biryukov (Serpukhov, IHEP)
Crystal channeling of LHC forward protons with preserved distribution in phase space
11 pages, 3 figures
Phys.Lett.B658:7-12,2007
10.1016/j.physletb.2007.10.051
null
hep-ph
null
We show that crystal can trap a broad (x, x', y, y', E) distribution of particles and channel it preserved with a high precision. This sampled-and-hold distribution can be steered by a bent crystal for analysis downstream. In simulations for the 7 TeV Large Hadron Collider, a crystal adapted to the accelerator lattice traps 90% of diffractively scattered protons emerging from the interaction point with a divergence 100 times the critical angle. We set the criterion for crystal adaptation improving efficiency ~100-fold. Proton angles are preserved in crystal transmission with accuracy down to 0.1 microrad. This makes feasible a crystal application for measuring very forward protons at the LHC.
[ { "created": "Sat, 31 Mar 2007 14:14:46 GMT", "version": "v1" } ]
2008-11-26
[ [ "Biryukov", "V. M.", "", "Serpukhov, IHEP" ] ]
We show that crystal can trap a broad (x, x', y, y', E) distribution of particles and channel it preserved with a high precision. This sampled-and-hold distribution can be steered by a bent crystal for analysis downstream. In simulations for the 7 TeV Large Hadron Collider, a crystal adapted to the accelerator lattice traps 90% of diffractively scattered protons emerging from the interaction point with a divergence 100 times the critical angle. We set the criterion for crystal adaptation improving efficiency ~100-fold. Proton angles are preserved in crystal transmission with accuracy down to 0.1 microrad. This makes feasible a crystal application for measuring very forward protons at the LHC.
2206.04501
Zhou Rui
Zhou Rui, Chao-Qi Zhang, Jia-Ming Li, and Meng-Kun Jia
Investigating the color-suppressed decays $\Lambda_b\rightarrow \Lambda \psi$ in the perturbative QCD approach
22 pages, 1 figure, 9 tables, match published version
Phys. Rev. D 106 (2022) 053005
10.1103/PhysRevD.106.053005
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The nonleptonic two-body $\Lambda_b\rightarrow \Lambda\psi $ decays with $\psi=J/\psi$ or $\psi(2S)$ are investigated based on the perturbative QCD approach. These are color-suppressed processes in which the nonfactorizable contributions are confirmed to be dominant. Angular momentum conservation allows us to describe the concerned decays by four independent complex helicity amplitudes. It is observed that the negative-helicity states for the $\Lambda$ baryon are preferred as expected in the left-handed nature of the charged-current interaction. The obtained results for the helicity amplitudes are used to compute the branching ratios and various observable parameters, which are then compared to the existing theoretical predictions and experimental data. In particular, we predict the ratio $\mathcal{R}=\frac{\mathcal{B}(\Lambda_b\rightarrow\Lambda \psi(2S))}{\mathcal{B}(\Lambda_b\rightarrow\Lambda J/\psi)}=0.47^{+0.02}_{-0.00}$ in comparison with $0.508\pm 0.023$ from the Particle Data Group at the level of 1 standard deviation. We also briefly explore the long-distance contributions to the semileptonic $\Lambda_b \rightarrow \Lambda l^+l^-$ decays in the kinematic regions where the dilepton invariant masses are around the $J/\psi$ and $\psi(2S)$ resonances.
[ { "created": "Thu, 9 Jun 2022 13:37:44 GMT", "version": "v1" }, { "created": "Thu, 22 Sep 2022 15:01:13 GMT", "version": "v2" } ]
2022-09-23
[ [ "Rui", "Zhou", "" ], [ "Zhang", "Chao-Qi", "" ], [ "Li", "Jia-Ming", "" ], [ "Jia", "Meng-Kun", "" ] ]
The nonleptonic two-body $\Lambda_b\rightarrow \Lambda\psi $ decays with $\psi=J/\psi$ or $\psi(2S)$ are investigated based on the perturbative QCD approach. These are color-suppressed processes in which the nonfactorizable contributions are confirmed to be dominant. Angular momentum conservation allows us to describe the concerned decays by four independent complex helicity amplitudes. It is observed that the negative-helicity states for the $\Lambda$ baryon are preferred as expected in the left-handed nature of the charged-current interaction. The obtained results for the helicity amplitudes are used to compute the branching ratios and various observable parameters, which are then compared to the existing theoretical predictions and experimental data. In particular, we predict the ratio $\mathcal{R}=\frac{\mathcal{B}(\Lambda_b\rightarrow\Lambda \psi(2S))}{\mathcal{B}(\Lambda_b\rightarrow\Lambda J/\psi)}=0.47^{+0.02}_{-0.00}$ in comparison with $0.508\pm 0.023$ from the Particle Data Group at the level of 1 standard deviation. We also briefly explore the long-distance contributions to the semileptonic $\Lambda_b \rightarrow \Lambda l^+l^-$ decays in the kinematic regions where the dilepton invariant masses are around the $J/\psi$ and $\psi(2S)$ resonances.
hep-ph/0606101
Alexander Friedland
Alexander Friedland, Cecilia Lunardini
Two modes of searching for new neutrino interactions at MINOS
10 pages, 3 figures; noticed typos corrected, results unchanged
Phys.Rev. D74 (2006) 033012
10.1103/PhysRevD.74.033012
LA-UR-06-3973
hep-ph hep-ex
null
The SuperKamiokande atmospheric neutrino measurements leave substantial room for nonstandard interactions (NSI) of neutrinos with matter in the nu_e- nu_tau sector. Large values of the NSI couplings are accommodated if the vacuum oscillation parameters are changed from their standard values. Short and medium baseline neutrino beams can break this degeneracy by measuring the true vacuum oscillation parameters with the muon neutrino disappearance mode, for which the matter effects are negligible or subdominant. These experiments can also search for the nu_e-nu_tau flavor changing effects directly, by looking for nu_mu->nu_e conversion caused by the intervening matter. We discuss both of these methods for the case of MINOS. We find that, while the present MINOS data on nu_mu disappearance induce only minor changes on the constraints on the NSI parameters, the situation will improve markedly with the planned increase of the statistics by an order of magnitude. In that case, the precision will be enough to distinguish certain presently allowed NSI scenarios from the no-NSI case. NSI per quark of about 10% the size of the standard weak interaction could give a nu_mu - nu_e conversion probability of the order ~ 10^{-2}, measurable by MINOS in the same high statistics scenario. In this nu_mu - nu_e channel, the small effects of NSI could be comparable or larger than the vacuum contribution of the small angle theta_{13}. The expected theta_{13} bound at MINOS should be more properly interpreted as a bound in the theta_{13}-NSI parameter space.
[ { "created": "Thu, 8 Jun 2006 19:58:29 GMT", "version": "v1" }, { "created": "Sat, 8 Jul 2006 00:46:00 GMT", "version": "v2" } ]
2009-11-11
[ [ "Friedland", "Alexander", "" ], [ "Lunardini", "Cecilia", "" ] ]
The SuperKamiokande atmospheric neutrino measurements leave substantial room for nonstandard interactions (NSI) of neutrinos with matter in the nu_e- nu_tau sector. Large values of the NSI couplings are accommodated if the vacuum oscillation parameters are changed from their standard values. Short and medium baseline neutrino beams can break this degeneracy by measuring the true vacuum oscillation parameters with the muon neutrino disappearance mode, for which the matter effects are negligible or subdominant. These experiments can also search for the nu_e-nu_tau flavor changing effects directly, by looking for nu_mu->nu_e conversion caused by the intervening matter. We discuss both of these methods for the case of MINOS. We find that, while the present MINOS data on nu_mu disappearance induce only minor changes on the constraints on the NSI parameters, the situation will improve markedly with the planned increase of the statistics by an order of magnitude. In that case, the precision will be enough to distinguish certain presently allowed NSI scenarios from the no-NSI case. NSI per quark of about 10% the size of the standard weak interaction could give a nu_mu - nu_e conversion probability of the order ~ 10^{-2}, measurable by MINOS in the same high statistics scenario. In this nu_mu - nu_e channel, the small effects of NSI could be comparable or larger than the vacuum contribution of the small angle theta_{13}. The expected theta_{13} bound at MINOS should be more properly interpreted as a bound in the theta_{13}-NSI parameter space.
1908.10618
Guruprasad Kadam Dr.
Guruprasad Kadam, Somenath Pal and Abhijit Bhattacharyya
Interacting hadron resonance gas model in magnetic field and the fluctuations of conserved charges
Revised manuscript, 20 pages, 8 captioned figures, Accepted for publication in Journal of Physics G
J.Phys.G 47 (2020) 125106
10.1088/1361-6471/abba70
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper we discuss the interacting hadron resonance gas model in presence of a constant external magnetic field. The short range repulsive interaction between hadrons are accounted through van der Waals excluded volume correction to the ideal gas pressure. Here we take the sizes of hadrons as $r_\pi$ (pion radius) $= 0$ fm, $r_K$ (kaon radius) $= 0.35$ fm, $r_m$ (all other meson radii) $= 0.3$ fm and $r_b$ (baryon radii) $= 0.5$ fm. We analyse the effect of uniform background magnetic field on the thermodynamic properties of interacting hadron gas. We especially discuss the effect of interactions on the behaviour of magnetization of low temperature hadronic matter. The vacuum terms have been regularized using magnetic field independent regularization scheme. We find that the magnetization of hadronic matter is positive which implies that the low temperature hadronic matter is paramagnetic. We further find that the repulsive interactions have very negligible effect on the overall magnetization of the hadronic matter and the paramagnetic property of the hadronic phase remains unchanged. We have also investigated the effects of short range repulsive interactions as well as the magnetic field on the baryon and electric charge number susceptibilities of hadronic matter within the ambit of excluded volume hadron resonance gas model.
[ { "created": "Wed, 28 Aug 2019 09:57:27 GMT", "version": "v1" }, { "created": "Tue, 22 Sep 2020 16:47:37 GMT", "version": "v2" } ]
2021-01-01
[ [ "Kadam", "Guruprasad", "" ], [ "Pal", "Somenath", "" ], [ "Bhattacharyya", "Abhijit", "" ] ]
In this paper we discuss the interacting hadron resonance gas model in presence of a constant external magnetic field. The short range repulsive interaction between hadrons are accounted through van der Waals excluded volume correction to the ideal gas pressure. Here we take the sizes of hadrons as $r_\pi$ (pion radius) $= 0$ fm, $r_K$ (kaon radius) $= 0.35$ fm, $r_m$ (all other meson radii) $= 0.3$ fm and $r_b$ (baryon radii) $= 0.5$ fm. We analyse the effect of uniform background magnetic field on the thermodynamic properties of interacting hadron gas. We especially discuss the effect of interactions on the behaviour of magnetization of low temperature hadronic matter. The vacuum terms have been regularized using magnetic field independent regularization scheme. We find that the magnetization of hadronic matter is positive which implies that the low temperature hadronic matter is paramagnetic. We further find that the repulsive interactions have very negligible effect on the overall magnetization of the hadronic matter and the paramagnetic property of the hadronic phase remains unchanged. We have also investigated the effects of short range repulsive interactions as well as the magnetic field on the baryon and electric charge number susceptibilities of hadronic matter within the ambit of excluded volume hadron resonance gas model.
0909.2836
Emiliano Molinaro
E. Molinaro, S.T. Petcov
On the Interplay Between the 'Low' and 'High' Energy CP-Violation in Leptogenesis
Submitted to the proceedings of "The 2009 Europhysics Conference on High Energy Physics", July 16 - 22, 2009, Krakow, Poland
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The CP-violation necessary for the generation of the baryon asymmetry of the Universe in the "flavoured" leptogenesis scenario can arise from the "low energy" PMNS neutrino mixing matrix and/or from the "high energy" part of neutrino Yukawa couplings, which can mediate CP-violating phenomena only at some high energy scale. The possible interplay between these two types of CP-violation is discussed. The type I see-saw model with three heavy right-handed Majorana neutrinos having hierarchical spectrum is considered. The analysis shows that there exist regions in the leptogenesis parameter space where the relevant "high energy" phases have large CP-violating values, but the purely "high energy" contribution to the baryon asymmetry plays a subdominant/suppressed role in the production of baryon asymmetry compatible with the observations and one can have successful leptogenesis if the requisite CP-violation is provided by the Majorana phase(s) in the neutrino mixing matrix.
[ { "created": "Tue, 15 Sep 2009 16:31:14 GMT", "version": "v1" } ]
2009-09-16
[ [ "Molinaro", "E.", "" ], [ "Petcov", "S. T.", "" ] ]
The CP-violation necessary for the generation of the baryon asymmetry of the Universe in the "flavoured" leptogenesis scenario can arise from the "low energy" PMNS neutrino mixing matrix and/or from the "high energy" part of neutrino Yukawa couplings, which can mediate CP-violating phenomena only at some high energy scale. The possible interplay between these two types of CP-violation is discussed. The type I see-saw model with three heavy right-handed Majorana neutrinos having hierarchical spectrum is considered. The analysis shows that there exist regions in the leptogenesis parameter space where the relevant "high energy" phases have large CP-violating values, but the purely "high energy" contribution to the baryon asymmetry plays a subdominant/suppressed role in the production of baryon asymmetry compatible with the observations and one can have successful leptogenesis if the requisite CP-violation is provided by the Majorana phase(s) in the neutrino mixing matrix.
hep-ph/0412315
Junjie Cao
Junjie Cao, Jin Min Yang
Lightest Higgs Boson Mass in Split Supersymmetry with See-saw Mechanism
minor changes, version in PRD(Rapid Communication)
Phys.Rev.D71:111701,2005
10.1103/PhysRevD.71.111701
null
hep-ph hep-ex
null
In the minimal supersymmetric standard model extended by including right-handed neutrinos with see-saw mechanism, the neutrino Yukaka couplings can be as large as the top-quark Yukawa couplings and thus the neutrino/sneutrino may cause sizable effects in Higgs boson self-energy loops. Our explicit one-loop calculations show that the neutrino/sneutrino effects may have an opposite sign to top/stop effects and thus lighten the lightest Higgs boson. If the soft-breaking mass of the right-handed neutrino is very large (at the order of Majorana mass scale), such as in the split-SUSY scenario, the effects can lower the lightest Higgs boson mass by a few tens of GeV. So the Higgs mass bound of about 150 GeV in split-SUSY may be lowered significantly if right-handed neutrinos come into play with see-saw mechanism.
[ { "created": "Tue, 21 Dec 2004 15:57:24 GMT", "version": "v1" }, { "created": "Wed, 22 Jun 2005 07:45:49 GMT", "version": "v2" } ]
2011-07-19
[ [ "Cao", "Junjie", "" ], [ "Yang", "Jin Min", "" ] ]
In the minimal supersymmetric standard model extended by including right-handed neutrinos with see-saw mechanism, the neutrino Yukaka couplings can be as large as the top-quark Yukawa couplings and thus the neutrino/sneutrino may cause sizable effects in Higgs boson self-energy loops. Our explicit one-loop calculations show that the neutrino/sneutrino effects may have an opposite sign to top/stop effects and thus lighten the lightest Higgs boson. If the soft-breaking mass of the right-handed neutrino is very large (at the order of Majorana mass scale), such as in the split-SUSY scenario, the effects can lower the lightest Higgs boson mass by a few tens of GeV. So the Higgs mass bound of about 150 GeV in split-SUSY may be lowered significantly if right-handed neutrinos come into play with see-saw mechanism.
hep-ph/0211307
Raymond R. Volkas
R. R. Volkas
Implications of the JHF-Kamioka neutrino oscillation experiment
10 pages, 3 figures, LaTeX, ws-procs9x6.cls. Invited talk at the Workshop on Physics at the Japan Hadron Facility (JHF), Adelaide, 14-21 March 2002
null
10.1142/9789812776662_0006
null
hep-ph hep-ex
null
After quickly reviewing the existing evidence for neutrino oscillations, I summarise the goals and capabilities of the JHF-Kamioka long baseline superbeam experiment. Theoretical implications of what this experiment could potentially discover are then discussed.
[ { "created": "Wed, 20 Nov 2002 05:18:40 GMT", "version": "v1" } ]
2017-08-23
[ [ "Volkas", "R. R.", "" ] ]
After quickly reviewing the existing evidence for neutrino oscillations, I summarise the goals and capabilities of the JHF-Kamioka long baseline superbeam experiment. Theoretical implications of what this experiment could potentially discover are then discussed.
hep-ph/9801432
Robert Harlander
K.G. Chetyrkin, R. Harlander and M. Steinhauser
Singlet Polarization Functions at O(\alpha_s^2)
LaTeX, 15 pages, 10 figures included as ps-files. The complete paper is also available via anonymous ftp at ftp://ttpux2.physik.uni-karlsruhe.de/ , or via www at http://www-ttp.physik.uni-karlsruhe.de/cgi-bin/preprints/
Phys. Rev. D 58, 014012 (1998)
10.1103/PhysRevD.58.014012
MPI/PhT/98-06, TTP98-04
hep-ph
null
We consider the three-loop singlet diagrams induced by axial-vector, scalar and pseudo-scalar currents. Expansions for small and large external momentum $q$ are presented. They are used in combination with conformal mapping and Pad\'e approximations in order to arrive at results for the polarization functions valid for all $q^2$. Results are presented for the imaginary parts which are directly related to physical quantities like the production of top quarks or the decay of scalar or pseudo-scalar Higgs bosons.
[ { "created": "Thu, 29 Jan 1998 07:48:41 GMT", "version": "v1" } ]
2016-08-25
[ [ "Chetyrkin", "K. G.", "" ], [ "Harlander", "R.", "" ], [ "Steinhauser", "M.", "" ] ]
We consider the three-loop singlet diagrams induced by axial-vector, scalar and pseudo-scalar currents. Expansions for small and large external momentum $q$ are presented. They are used in combination with conformal mapping and Pad\'e approximations in order to arrive at results for the polarization functions valid for all $q^2$. Results are presented for the imaginary parts which are directly related to physical quantities like the production of top quarks or the decay of scalar or pseudo-scalar Higgs bosons.
hep-ph/0110148
Namit Mahajan
Namit Mahajan (Univ. of Delhi)
Noncommutative QED and $\gamma\gamma$ scattering
Minor corrections made and references added
null
null
null
hep-ph
null
We study $\gamma\gamma$ scattering in noncommutative QED (NCQED) where the gauge field has Yang-Mills type coupling, giving new contributions to the scattering process and making it possible for it to occur at tree level. The process takes place at one loop level in the Standard Model (SM) and could be an important signal for physics beyond SM. But it is found that the Standard Model contribution far exceeds the tree level contribution of the noncommutative case.
[ { "created": "Thu, 11 Oct 2001 09:49:54 GMT", "version": "v1" }, { "created": "Wed, 7 Nov 2001 06:00:32 GMT", "version": "v2" } ]
2007-05-23
[ [ "Mahajan", "Namit", "", "Univ. of Delhi" ] ]
We study $\gamma\gamma$ scattering in noncommutative QED (NCQED) where the gauge field has Yang-Mills type coupling, giving new contributions to the scattering process and making it possible for it to occur at tree level. The process takes place at one loop level in the Standard Model (SM) and could be an important signal for physics beyond SM. But it is found that the Standard Model contribution far exceeds the tree level contribution of the noncommutative case.
1103.4131
Sandro Casagrande
Sandro Casagrande
Indirect tests of the Randall-Sundrum model
8 pages, 6 figures; Talk given at Discrete '10: Symposium on Prospects in the Physics of Discrete Symmetries, Rome, Italy, 6-11 Dec 2010
null
10.1088/1742-6596/335/1/012018
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
I present phenomenological implications of the Randall-Sundrum model for indirect searches, specifically a selection of flavor observables and Higgs-related collider searches. I review the interplay of constraints from CP violation in flavor physics, possible effects in rare decays, and model-specific protection mechanisms. Deviations in the Higgs couplings to fermions and, at one-loop, to gluons are unexpectedly strong and lead to strong modifications in Higgs searches.
[ { "created": "Mon, 21 Mar 2011 20:00:43 GMT", "version": "v1" } ]
2015-05-27
[ [ "Casagrande", "Sandro", "" ] ]
I present phenomenological implications of the Randall-Sundrum model for indirect searches, specifically a selection of flavor observables and Higgs-related collider searches. I review the interplay of constraints from CP violation in flavor physics, possible effects in rare decays, and model-specific protection mechanisms. Deviations in the Higgs couplings to fermions and, at one-loop, to gluons are unexpectedly strong and lead to strong modifications in Higgs searches.
hep-ph/9709279
Gi-Chol Cho
Gi-Chol Cho and Kaoru Hagiwara (Theory group, KEK)
String unification scale and the hyper-charge Kac-Moody level in the non-supersymmetric standard model
LaTeX, 13pages, 3 figures. Some comments are added. Final version to appear in Phys. Lett. B
Phys.Lett. B419 (1998) 199-205
10.1016/S0370-2693(97)01488-3
KEK-TH-537
hep-ph
null
The string theory predicts the unification of the gauge couplings and gravity. The minimal supersymmetric Standard Model, however, gives the unification scale $\sim 2\times 10^{16}$ GeV which is significantly smaller than the string scale $\sim 5\times 10^{17}$ GeV of the weak coupling heterotic string theory. We study the unification scale of the non-supersymmetric minimal Standard Model quantitatively at the two-loop level. We find that the unification scale should be at most $\sim 4\times 10^{16}$ GeV and the desired Kac-Moody level of the hyper-charge coupling should be $1.33 \lsim \ky \lsim 1.35$ in the absence of significant string threshold effects.
[ { "created": "Mon, 8 Sep 1997 09:42:10 GMT", "version": "v1" }, { "created": "Tue, 9 Sep 1997 03:19:19 GMT", "version": "v2" }, { "created": "Wed, 26 Nov 1997 08:48:10 GMT", "version": "v3" } ]
2009-10-30
[ [ "Cho", "Gi-Chol", "", "Theory group, KEK" ], [ "Hagiwara", "Kaoru", "", "Theory group, KEK" ] ]
The string theory predicts the unification of the gauge couplings and gravity. The minimal supersymmetric Standard Model, however, gives the unification scale $\sim 2\times 10^{16}$ GeV which is significantly smaller than the string scale $\sim 5\times 10^{17}$ GeV of the weak coupling heterotic string theory. We study the unification scale of the non-supersymmetric minimal Standard Model quantitatively at the two-loop level. We find that the unification scale should be at most $\sim 4\times 10^{16}$ GeV and the desired Kac-Moody level of the hyper-charge coupling should be $1.33 \lsim \ky \lsim 1.35$ in the absence of significant string threshold effects.
1707.05195
Antonio Enrique C\'arcamo Hern\'andez acarcamo
A. E. C\'arcamo Hern\'andez, Basti\'an D\'iaz S\'aez, Claudio O. Dib, Alfonso Zerwekh
Constraints on vector resonances from a strong Higgs sector
14 pages, 18 figures. arXiv admin note: text overlap with arXiv:1506.03631
Phys. Rev. D 96, 115027 (2017)
10.1103/PhysRevD.96.115027
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider a scenario of a composite Higgs arising from a strong sector. We assume that the lowest lying composite states are the Higgs scalar doublet and a massive vector triplet, whose dynamics below the compositeness scale are described in terms of an effective Lagrangian. Electroweak symmetry breaking takes place through a vacuum expectation value just as in the Standard Model, but with the vector resonances strongly coupled to the Higgs field. We determine the constraints on this scenario imposed by (i) the Higgs diphoton decay rate, (ii) the electroweak precision tests and (iii) searches of heavy resonances at the LHC in the final states $l^+l^-$ and $l\nu_l$ ($l=e,\mu$), $\tau^+\tau^-$, $jj$, $t\bar{t}$, $WZ$, $WW$, $WH$ and $ZH$. We find that the heavy vector resonances should have masses that are constrained to be in the range $2.1$ - $3$ TeV. On the other hand, the mixing of the heavy vectors with the Standard Model gauge bosons is constrained to be in the range $\tan\vartheta\sim 0.1 - 0.3$, which is consistent with the assumption that the Higgs couples weakly to the Standard sector, even though it couples strongly to the heavy vector resonances.
[ { "created": "Thu, 13 Jul 2017 21:13:21 GMT", "version": "v1" } ]
2018-01-03
[ [ "Hernández", "A. E. Cárcamo", "" ], [ "Sáez", "Bastián Díaz", "" ], [ "Dib", "Claudio O.", "" ], [ "Zerwekh", "Alfonso", "" ] ]
We consider a scenario of a composite Higgs arising from a strong sector. We assume that the lowest lying composite states are the Higgs scalar doublet and a massive vector triplet, whose dynamics below the compositeness scale are described in terms of an effective Lagrangian. Electroweak symmetry breaking takes place through a vacuum expectation value just as in the Standard Model, but with the vector resonances strongly coupled to the Higgs field. We determine the constraints on this scenario imposed by (i) the Higgs diphoton decay rate, (ii) the electroweak precision tests and (iii) searches of heavy resonances at the LHC in the final states $l^+l^-$ and $l\nu_l$ ($l=e,\mu$), $\tau^+\tau^-$, $jj$, $t\bar{t}$, $WZ$, $WW$, $WH$ and $ZH$. We find that the heavy vector resonances should have masses that are constrained to be in the range $2.1$ - $3$ TeV. On the other hand, the mixing of the heavy vectors with the Standard Model gauge bosons is constrained to be in the range $\tan\vartheta\sim 0.1 - 0.3$, which is consistent with the assumption that the Higgs couples weakly to the Standard sector, even though it couples strongly to the heavy vector resonances.
1405.3957
Tanumoy Mandal
Gilad Amar, Shankha Banerjee, Stefan von Buddenbrock, Alan S. Cornell, Tanumoy Mandal, Bruce Mellado, Biswarup Mukhopadhyaya
Exploration of the Tensor Structure of the Higgs Boson Coupling to Weak Bosons in $e^+e^-$ Collisions
38 pages, 15 figures, 2 tables, matches with published version
JHEP 1502 (2015) 128
10.1007/JHEP02(2015)128
HRI-RECAPP-2014-011,WITS-CTP-135
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Probing signatures of anomalous interactions of the Higgs boson with pairs of weak vector bosons is an important goal of an $e^+e^-$ collider commissioned as a Higgs factory. We perform a detailed analysis of such potential of a collider operating at $250 - 300$ GeV. Mostly using higher dimensional operators in a gauge-invariant framework, we show that substantial information on anomalous couplings can be extracted from the total rates of $s$-and $t$-channel Higgs production. The most obvious kinematic distributions, based on angular dependence of matrix elements, are relatively less sensitive with moderate coefficients of anomalous couplings, unless one goes to higher centre-of-mass energies. Some important quantities to use here, apart from the total event rates, are the ratios of event rates at different energies, ratios of $s$ and $t$-channel rates at fixed energies, and under some fortunate circumstances, the correlated changes in the rates for $W$-boson pair-production. A general scheme of calculating rates with as many as four gauge-invariant operators is also outlined. At the end, we perform a likelihood analysis using phenomenological parametrization of anomalous $HWW$ interaction, and indicate their distinguishability for illustrative values of the strength of such interactions.
[ { "created": "Thu, 15 May 2014 19:26:33 GMT", "version": "v1" }, { "created": "Sat, 20 Sep 2014 14:52:32 GMT", "version": "v2" }, { "created": "Mon, 16 Mar 2015 12:30:39 GMT", "version": "v3" } ]
2015-03-17
[ [ "Amar", "Gilad", "" ], [ "Banerjee", "Shankha", "" ], [ "von Buddenbrock", "Stefan", "" ], [ "Cornell", "Alan S.", "" ], [ "Mandal", "Tanumoy", "" ], [ "Mellado", "Bruce", "" ], [ "Mukhopadhyaya", "Biswarup", "" ] ]
Probing signatures of anomalous interactions of the Higgs boson with pairs of weak vector bosons is an important goal of an $e^+e^-$ collider commissioned as a Higgs factory. We perform a detailed analysis of such potential of a collider operating at $250 - 300$ GeV. Mostly using higher dimensional operators in a gauge-invariant framework, we show that substantial information on anomalous couplings can be extracted from the total rates of $s$-and $t$-channel Higgs production. The most obvious kinematic distributions, based on angular dependence of matrix elements, are relatively less sensitive with moderate coefficients of anomalous couplings, unless one goes to higher centre-of-mass energies. Some important quantities to use here, apart from the total event rates, are the ratios of event rates at different energies, ratios of $s$ and $t$-channel rates at fixed energies, and under some fortunate circumstances, the correlated changes in the rates for $W$-boson pair-production. A general scheme of calculating rates with as many as four gauge-invariant operators is also outlined. At the end, we perform a likelihood analysis using phenomenological parametrization of anomalous $HWW$ interaction, and indicate their distinguishability for illustrative values of the strength of such interactions.
0710.4055
Marek Karliner
Marek Karliner and Harry J. Lipkin
Possibility of Narrow High-Mass Exotic States
LaTeX, 7 pages, 2 figures
null
null
TAUP 2865/07, WIS/17/07-OCT-DPP, ANL-HEP-PR-707-88
hep-ph
null
Narrow high-mass states can arise despite large phase space when two nearly degenerate states are coupled to the same dominant decay mode. Mixing via a final-state interaction loop diagram can produce one very broad state and one narrow state. Such a situation is generic in exotic hadrons where a color singlet with given flavor and spin quantum numbers can be constructed with two distinct internal color couplings of quarks. The simplest realization of this idea are the (Q Qbar q qbar) tetraquarks containing two heavy and two light quarks. We discuss possible experimental implications, including recent data from Belle.
[ { "created": "Mon, 22 Oct 2007 13:36:48 GMT", "version": "v1" } ]
2007-10-23
[ [ "Karliner", "Marek", "" ], [ "Lipkin", "Harry J.", "" ] ]
Narrow high-mass states can arise despite large phase space when two nearly degenerate states are coupled to the same dominant decay mode. Mixing via a final-state interaction loop diagram can produce one very broad state and one narrow state. Such a situation is generic in exotic hadrons where a color singlet with given flavor and spin quantum numbers can be constructed with two distinct internal color couplings of quarks. The simplest realization of this idea are the (Q Qbar q qbar) tetraquarks containing two heavy and two light quarks. We discuss possible experimental implications, including recent data from Belle.
2009.05616
Peter Lichard
Peter Lichard
Possible manifestation of the 2p pionium in particle physics processes
11 pages, 11 figures, 5 tables
Phys. Rev. D 102, 073004 (2020)
10.1103/PhysRevD.102.073004
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We suggest a few particle physics processes in which excited 2p pionium $\mathrm{A}^\prime_{2\pi}$ may be observed. They include the $e^+e^-\to\pi^+\pi^-$ annihilation, the $V^0\to\pi^0\ell^+\ell^-$ and $K^\pm\to\pi^\pm\ell^+\ell^-$ ($\ell=e,\mu$) decays, and the photoproduction of two neutral pions from nucleons. We analyze available experimental data and find that they, in some cases, indicate the presence of 2p pionium, but do not provide definite proof.
[ { "created": "Fri, 11 Sep 2020 18:57:34 GMT", "version": "v1" }, { "created": "Sun, 18 Oct 2020 17:27:07 GMT", "version": "v2" } ]
2020-10-20
[ [ "Lichard", "Peter", "" ] ]
We suggest a few particle physics processes in which excited 2p pionium $\mathrm{A}^\prime_{2\pi}$ may be observed. They include the $e^+e^-\to\pi^+\pi^-$ annihilation, the $V^0\to\pi^0\ell^+\ell^-$ and $K^\pm\to\pi^\pm\ell^+\ell^-$ ($\ell=e,\mu$) decays, and the photoproduction of two neutral pions from nucleons. We analyze available experimental data and find that they, in some cases, indicate the presence of 2p pionium, but do not provide definite proof.
hep-ph/0004081
Kazunori Itakura
K. Itakura and S. Maedan
Dynamical Chiral Symmetry Breaking on the Light Front.II. The Nambu--Jona-Lasinio Model
23 pages, REVTEX, the version to be published in Phys.Rev.D; Some clarifications in discussion of the LC wavefunctions added
Phys.Rev. D62 (2000) 105016
10.1103/PhysRevD.62.105016
RCNP-Th-00010
hep-ph hep-th nucl-th
null
An investigation of dynamical chiral symmetry breaking on the light front is made in the Nambu--Jona-Lasinio model with one flavor and N colors. Analysis of the model suffers from extraordinary complexity due to the existence of a "fermionic constraint," i.e., a constraint equation for the bad spinor component. However, to solve this constraint is of special importance. In classical theory, we can exactly solve it and then explicitly check the property of ``light-front chiral transformation.'' In quantum theory, we introduce a bilocal formulation to solve the fermionic constraint by the 1/N expansion. Systematic 1/N expansion of the fermion bilocal operator is realized by the boson expansion method. The leading (bilocal) fermionic constraint becomes a gap equation for a chiral condensate and thus if we choose a nontrivial solution of the gap equation, we are in the broken phase. As a result of the nonzero chiral condensate, we find unusual chiral transformation of fields and nonvanishing of the light-front chiral charge. A leading order eigenvalue equation for a single bosonic state is equivalent to a leading order fermion-antifermion bound-state equation. We analytically solve it for scalar and pseudoscalar mesons and obtain their light-cone wavefunctions and masses. All of the results are entirely consistent with those of our previous analysis on the chiral Yukawa model.
[ { "created": "Sat, 8 Apr 2000 13:39:18 GMT", "version": "v1" }, { "created": "Mon, 3 Jul 2000 02:00:23 GMT", "version": "v2" } ]
2009-10-31
[ [ "Itakura", "K.", "" ], [ "Maedan", "S.", "" ] ]
An investigation of dynamical chiral symmetry breaking on the light front is made in the Nambu--Jona-Lasinio model with one flavor and N colors. Analysis of the model suffers from extraordinary complexity due to the existence of a "fermionic constraint," i.e., a constraint equation for the bad spinor component. However, to solve this constraint is of special importance. In classical theory, we can exactly solve it and then explicitly check the property of ``light-front chiral transformation.'' In quantum theory, we introduce a bilocal formulation to solve the fermionic constraint by the 1/N expansion. Systematic 1/N expansion of the fermion bilocal operator is realized by the boson expansion method. The leading (bilocal) fermionic constraint becomes a gap equation for a chiral condensate and thus if we choose a nontrivial solution of the gap equation, we are in the broken phase. As a result of the nonzero chiral condensate, we find unusual chiral transformation of fields and nonvanishing of the light-front chiral charge. A leading order eigenvalue equation for a single bosonic state is equivalent to a leading order fermion-antifermion bound-state equation. We analytically solve it for scalar and pseudoscalar mesons and obtain their light-cone wavefunctions and masses. All of the results are entirely consistent with those of our previous analysis on the chiral Yukawa model.
hep-ph/0001198
Giorgio Calucci
Giorgio Calucci and Daniele Treleani
A Hamiltonian model for multiple production in hadron-hadron collisions
LateX No figures 9pages Proc. Conference ISMD1998 Delphi (GR)
Proc. Conference ISMD1998 Delphi (GR)
null
null
hep-ph
null
A Hamiltonian eikonal model for the multiple production in high energy hadron hadron collisions is presented and worked out in the aim of providing a simple frame for many different observables of these processes. The Hamiltonian formulation ensures that it has the unitarity built in by construction and the eikonal approximation makes easier the discussion of the possible spacial inhomogeneities of the hadrons. The experimental data which are examined are the inelastic cross section and the single and double inclusive cross sections.
[ { "created": "Wed, 19 Jan 2000 16:28:17 GMT", "version": "v1" } ]
2007-05-23
[ [ "Calucci", "Giorgio", "" ], [ "Treleani", "Daniele", "" ] ]
A Hamiltonian eikonal model for the multiple production in high energy hadron hadron collisions is presented and worked out in the aim of providing a simple frame for many different observables of these processes. The Hamiltonian formulation ensures that it has the unitarity built in by construction and the eikonal approximation makes easier the discussion of the possible spacial inhomogeneities of the hadrons. The experimental data which are examined are the inelastic cross section and the single and double inclusive cross sections.
hep-ph/9602408
Sergio A. Pernice
S. A. Pernice
Fully Relativistic Quark Models for Heavy-Light Systems
38 pages, Latex, 8 figures. This version includes figures
Phys.Rev. D53 (1996) 1439-1451
10.1103/PhysRevD.53.1439
null
hep-ph hep-lat
null
A fully relativistic quark model is constructed and applied to the study of wave-functions as well as the spectrum of heavy-light mesons. The free parameters of the model are a constituent quark mass and (on the lattice) an adjustable r-parameter in the fermionic kinetic energy, while the confinement is introduced via potentials measured by MonteCarlo. The results are compared to Monte Carlo energies and Coulomb-gauge wave functions. They are in very good agreement with the data. A comparison with previous models suggests that we are seeing in the Monte Carlo data the quantum-relativistic delocalization of the quark due to Zitterbewegung.
[ { "created": "Tue, 27 Feb 1996 14:17:06 GMT", "version": "v1" }, { "created": "Sun, 3 Mar 1996 21:39:37 GMT", "version": "v2" } ]
2009-10-28
[ [ "Pernice", "S. A.", "" ] ]
A fully relativistic quark model is constructed and applied to the study of wave-functions as well as the spectrum of heavy-light mesons. The free parameters of the model are a constituent quark mass and (on the lattice) an adjustable r-parameter in the fermionic kinetic energy, while the confinement is introduced via potentials measured by MonteCarlo. The results are compared to Monte Carlo energies and Coulomb-gauge wave functions. They are in very good agreement with the data. A comparison with previous models suggests that we are seeing in the Monte Carlo data the quantum-relativistic delocalization of the quark due to Zitterbewegung.
hep-ph/0109245
Janusz Gluza
M. Czakon, (Univ. Karlsruhe), J. Gluza and M. Zralek (Univ. Silesia, Katowice)
Nonunitary neutrino mixing matrix and CP violating neutrino oscillations
10 pages, 4 figs, presented at the XXV International Conference on Theoretical Physics ``Particle Physics and Astrophysics in the Standard Model and Beyond, Ustron, Poland, September 2001
Acta Phys.Polon.B32:3735-3744,2001
null
null
hep-ph
null
In the standard approach to the neutrino oscillations a unitary relation among weak and mass eigenstates of light neutrinos is imposed. However, in many extensions of the SM left-handed, active neutrinos mix with additional heavy neutrino states. Consequences of this additional mixing, driven by experimental constraints, on the neutrino oscillations are considered.
[ { "created": "Wed, 26 Sep 2001 08:34:42 GMT", "version": "v1" } ]
2014-11-17
[ [ "Czakon", "M.", "", "Univ. Silesia,\n Katowice" ], [ "Gluza", "J.", "", "Univ. Silesia,\n Katowice" ], [ "Zralek", "M.", "", "Univ. Silesia,\n Katowice" ] ]
In the standard approach to the neutrino oscillations a unitary relation among weak and mass eigenstates of light neutrinos is imposed. However, in many extensions of the SM left-handed, active neutrinos mix with additional heavy neutrino states. Consequences of this additional mixing, driven by experimental constraints, on the neutrino oscillations are considered.
1912.07755
Luca Buonocore
Luca Buonocore
Recent developments in $q_T$ subtraction: EW corrections and power suppressed contributions
11 pages, 3 figures, to appear in the proceedings of the 14th International Symposium on Radiative Corrections (RADCOR2019)
null
null
C19-09-08
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The $q_T$ subtraction formalism represents a well established and successful technique to deal with the computation of QCD radiative corrections up to NNLO (and beyond) for a large class of processes relevant at the LHC. We have explored the possibility to apply $q_T$ subtraction to the computation of EW corrections with the (final) aim to develop a subtraction formalism suitable for the computation of mixed QCD-EW corrections. We present numerical results for the complete NLO EW corrections to the Drell-Yan production of a massive lepton pair. Furthermore, we have investigated the structure of the power suppressed contributions at small-$q_T$ in this process and we present new analytical results on the effects of the soft radiation emitted off a charged massive final state.
[ { "created": "Mon, 16 Dec 2019 23:26:41 GMT", "version": "v1" } ]
2019-12-18
[ [ "Buonocore", "Luca", "" ] ]
The $q_T$ subtraction formalism represents a well established and successful technique to deal with the computation of QCD radiative corrections up to NNLO (and beyond) for a large class of processes relevant at the LHC. We have explored the possibility to apply $q_T$ subtraction to the computation of EW corrections with the (final) aim to develop a subtraction formalism suitable for the computation of mixed QCD-EW corrections. We present numerical results for the complete NLO EW corrections to the Drell-Yan production of a massive lepton pair. Furthermore, we have investigated the structure of the power suppressed contributions at small-$q_T$ in this process and we present new analytical results on the effects of the soft radiation emitted off a charged massive final state.
1103.1481
Matthias Steinhauser
Jens Hoff and Matthias Steinhauser
Moments of heavy-light current correlators up to three loops
21 pages
null
10.1016/j.nuclphysb.2011.04.007
SFB/CPP-11-05, TTP11-02
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider moments of the non-diagonal vector, axial-vector, scalar and pseudo-scalar current correlators involving two different massive quark flavours up to three-loop accuracy. Expansions around the limits where one mass is zero and the equal-mass case are computed. These results are used to construct approximations valid for arbitrary mass values.
[ { "created": "Tue, 8 Mar 2011 10:11:02 GMT", "version": "v1" } ]
2015-05-27
[ [ "Hoff", "Jens", "" ], [ "Steinhauser", "Matthias", "" ] ]
We consider moments of the non-diagonal vector, axial-vector, scalar and pseudo-scalar current correlators involving two different massive quark flavours up to three-loop accuracy. Expansions around the limits where one mass is zero and the equal-mass case are computed. These results are used to construct approximations valid for arbitrary mass values.
2105.01666
Martin Hoferichter
Igor Danilkin, Martin Hoferichter, Peter Stoffer
A dispersive estimate of scalar contributions to hadronic light-by-light scattering
9 pages, 2 figures; journal version
Phys. Lett. B 820 (2021) 136502
10.1016/j.physletb.2021.136502
INT-PUB-21-11, UWThPh 2021-3
hep-ph hep-ex hep-lat nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider the contribution of scalar resonances to hadronic light-by-light scattering in the anomalous magnetic moment of the muon. While the $f_0(500)$ has already been addressed in previous work using dispersion relations, heavier scalar resonances have only been estimated in hadronic models so far. Here, we compare an implementation of the $f_0(980)$ resonance in terms of the coupled-channel $S$-waves for $\gamma^*\gamma^*\to \pi\pi/\bar K K$ to a narrow-width approximation, which indicates $a_\mu^{\text{HLbL}}[f_0(980)]=-0.2(2)\times 10^{-11}$. With a similar estimate for the $a_0(980)$, the combined effect is thus well below $1\times 10^{-11}$ in absolute value. We also estimate the contribution of heavier scalar resonances. In view of the very uncertain situation concerning their two-photon couplings we suggest to treat them together with other resonances of similar mass when imposing the matching to short-distance constraints. Our final result is a refined estimate of the $S$-wave rescattering effects in the $\pi \pi$ and $\bar K K$ channel up to about $1.3$ GeV and including a narrow-width evaluation of the $a_0(980)$: $a_\mu^\text{HLbL}[\text{scalars}]=-9(1)\times 10^{-11}$.
[ { "created": "Tue, 4 May 2021 18:00:01 GMT", "version": "v1" }, { "created": "Fri, 16 Jul 2021 07:17:12 GMT", "version": "v2" } ]
2021-07-19
[ [ "Danilkin", "Igor", "" ], [ "Hoferichter", "Martin", "" ], [ "Stoffer", "Peter", "" ] ]
We consider the contribution of scalar resonances to hadronic light-by-light scattering in the anomalous magnetic moment of the muon. While the $f_0(500)$ has already been addressed in previous work using dispersion relations, heavier scalar resonances have only been estimated in hadronic models so far. Here, we compare an implementation of the $f_0(980)$ resonance in terms of the coupled-channel $S$-waves for $\gamma^*\gamma^*\to \pi\pi/\bar K K$ to a narrow-width approximation, which indicates $a_\mu^{\text{HLbL}}[f_0(980)]=-0.2(2)\times 10^{-11}$. With a similar estimate for the $a_0(980)$, the combined effect is thus well below $1\times 10^{-11}$ in absolute value. We also estimate the contribution of heavier scalar resonances. In view of the very uncertain situation concerning their two-photon couplings we suggest to treat them together with other resonances of similar mass when imposing the matching to short-distance constraints. Our final result is a refined estimate of the $S$-wave rescattering effects in the $\pi \pi$ and $\bar K K$ channel up to about $1.3$ GeV and including a narrow-width evaluation of the $a_0(980)$: $a_\mu^\text{HLbL}[\text{scalars}]=-9(1)\times 10^{-11}$.
2006.12019
Desh Raj
S. Dev and Desh Raj
New Hybrid Textures for Neutrino Mass Matrices
null
Nuclear Physics B 957 (2020) 115081
10.1016/j.nuclphysb.2020.115081
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
We perform a systematic investigation of the texture structures of Majorana neutrino mass matrix $M_{\nu}$ having two texture zeros and an equality between two nonzero matrix elements, in the light of recent neutrino oscillation data. Among forty-two possible textures, it is found that only eight textures are compatible with the current experimental data at 3$\sigma$ C.L. Out of these phenomenologically viable textures, six follow normal mass ordering while remaining two satisfy the inverted mass ordering of neutrino mass spectrum. In the numerical analysis, we carry out a scan over the possible space of all viable patterns. We present the implications of each allowed patterns for three mixing angles (solar, reactor and atmospheric), leptonic CP-violation, neutrino mass scale and the neutrinoless double beta decay indicating strong correlations between oscillation parameters. The symmetry realization of one of the viable textures is also presented.
[ { "created": "Mon, 22 Jun 2020 05:58:59 GMT", "version": "v1" } ]
2020-06-23
[ [ "Dev", "S.", "" ], [ "Raj", "Desh", "" ] ]
We perform a systematic investigation of the texture structures of Majorana neutrino mass matrix $M_{\nu}$ having two texture zeros and an equality between two nonzero matrix elements, in the light of recent neutrino oscillation data. Among forty-two possible textures, it is found that only eight textures are compatible with the current experimental data at 3$\sigma$ C.L. Out of these phenomenologically viable textures, six follow normal mass ordering while remaining two satisfy the inverted mass ordering of neutrino mass spectrum. In the numerical analysis, we carry out a scan over the possible space of all viable patterns. We present the implications of each allowed patterns for three mixing angles (solar, reactor and atmospheric), leptonic CP-violation, neutrino mass scale and the neutrinoless double beta decay indicating strong correlations between oscillation parameters. The symmetry realization of one of the viable textures is also presented.
hep-ph/9808226
Arkady Vainshtein
Arkady Vainshtein
Heavy flavor decays and OPE in two-dimensional 't Hooft model
LaTex, 11 pages, 2 figures. Talk presented at the 3rd workshop on Continious Advances in QCD, University of Minnesota, Minneapolis, April 16-19, 1998
null
null
TPI-MINN-98/13-T, UMN-TH-1713-98
hep-ph
null
The 't Hooft model (two-dimensional QCD in the limit of large number of colors) is used as a testground for calculations of nonleptonic and semileptonic inclusive widths of heavy flavors based on the operator product expansion (OPE). The OPE-based predictions up to terms ${\cal O}(1/m_Q^4)$, inclusively, are confronted with the "phenomenological" results, obtained by summation of all open exclusive decay channels, one by one, a perfect match is found. The issue of duality violations is discussed, the amplitude of oscillating terms is estimated. The method is applied to the realistic case of hadronic $\tau$ decays.
[ { "created": "Wed, 5 Aug 1998 00:59:27 GMT", "version": "v1" } ]
2007-05-23
[ [ "Vainshtein", "Arkady", "" ] ]
The 't Hooft model (two-dimensional QCD in the limit of large number of colors) is used as a testground for calculations of nonleptonic and semileptonic inclusive widths of heavy flavors based on the operator product expansion (OPE). The OPE-based predictions up to terms ${\cal O}(1/m_Q^4)$, inclusively, are confronted with the "phenomenological" results, obtained by summation of all open exclusive decay channels, one by one, a perfect match is found. The issue of duality violations is discussed, the amplitude of oscillating terms is estimated. The method is applied to the realistic case of hadronic $\tau$ decays.
hep-ph/9703250
Takeo Matsuoka
N. Haba, N. Maru and T. Matsuoka
Supersymmetry Breaking Without A Messenger Sector
Revised version includes some corrections of the superpotential
Phys.Rev. D56 (1997) 4207-4212
10.1103/PhysRevD.56.4207
DPNU-97-14
hep-ph
null
We propose a simple gauge-mediated supersymmetry breaking model in which suitable soft breaking masses are dynamically generated without relying on a messenger sector. This model is constructed as an extention of the 3-2 model and needs no fine-tuning of parameters. The dynamical supersymmetry breaking sector contains non-renormalizable interactions and vector-like fields. Non-renormalizable terms are characterized by the couplings of O(1) in units of the Planck scale. The vacuum of this model conserves the color and electro-weak symmetry.
[ { "created": "Thu, 6 Mar 1997 06:01:12 GMT", "version": "v1" }, { "created": "Wed, 12 Mar 1997 07:34:07 GMT", "version": "v2" } ]
2009-10-30
[ [ "Haba", "N.", "" ], [ "Maru", "N.", "" ], [ "Matsuoka", "T.", "" ] ]
We propose a simple gauge-mediated supersymmetry breaking model in which suitable soft breaking masses are dynamically generated without relying on a messenger sector. This model is constructed as an extention of the 3-2 model and needs no fine-tuning of parameters. The dynamical supersymmetry breaking sector contains non-renormalizable interactions and vector-like fields. Non-renormalizable terms are characterized by the couplings of O(1) in units of the Planck scale. The vacuum of this model conserves the color and electro-weak symmetry.
1503.06519
Hoernisa Iminniyaz
Shun-zhi Wang, Hoernisa Iminniyaz, Mamatrishat Mamat
Relic Abundance of Asymmetric Dark Matter and the Scalar--Tensor Model
The whole structure of the paper is changed. The new figure is added and typos are corrected
null
10.1142/S0217751X16500214
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The relic abundance of asymmetric Dark Matter particles in the scalar--tensor model is analysized in this article. We extend the numeric and analytic calculation of the relic density of the asymmetric Dark Matter in the standard cosmological scenario to the nonstandard cosmological scenario. We focus on the scalar--tensor model. Hubble expansion rate is changed in the nonstandard cosmological scenario. This leaves its imprint on the relic density of Dark Matter particles. In this article we investigate to what extent the asymmetric Dark Matter particle's relic density is changed in the scalar--tensor model. We use the observed present day Dark Matter abundance to find the constraints on the parameter space in this model.
[ { "created": "Mon, 23 Mar 2015 03:54:44 GMT", "version": "v1" }, { "created": "Wed, 19 Aug 2015 05:47:41 GMT", "version": "v2" } ]
2016-03-16
[ [ "Wang", "Shun-zhi", "" ], [ "Iminniyaz", "Hoernisa", "" ], [ "Mamat", "Mamatrishat", "" ] ]
The relic abundance of asymmetric Dark Matter particles in the scalar--tensor model is analysized in this article. We extend the numeric and analytic calculation of the relic density of the asymmetric Dark Matter in the standard cosmological scenario to the nonstandard cosmological scenario. We focus on the scalar--tensor model. Hubble expansion rate is changed in the nonstandard cosmological scenario. This leaves its imprint on the relic density of Dark Matter particles. In this article we investigate to what extent the asymmetric Dark Matter particle's relic density is changed in the scalar--tensor model. We use the observed present day Dark Matter abundance to find the constraints on the parameter space in this model.
hep-ph/9806201
Arnulfo Zepeda
U. Cotti, R. Gaitan, A. Hernandez, W. Ponce, and A. Zepeda
Lepton mass generation and family number violation mechanism in the $SU(6)\otimes U(1)$ model
12 pages, Latex, 7 figures. Accepted for publication in Int. Journ. of Mod. Phys. A
Int.J.Mod.Phys. A13 (1998) 5557-5572
10.1142/S0217751X98002535
null
hep-ph
null
Lepton family number violation processes arise in the $SU(6)_L \otimes U(1)_Y$ model due to the presence of an extra neutral gauge boson, Z$'$, with family changing couplings, and due to the fact that this model demands the existence of heavy exotic leptons. The mixing of the standard Z with Z$'$ and the mixing of ordinary leptons with exotic ones induce together family changing couplings on the Z and therefore nonvanishing rates for lepton family number violation processes, such as $Z \to e \bar{\mu}$, $\mu \to ee\bar{e}$ and $\mu \to e\gamma$. Additional contributions to the processes $\mu \to e \gamma$ and $\mu \to ee \bar{e}$ are induced from the mass generation mechanism. This last type of contributions may compete with the above one, depending on the masses of the scalars which participate in the diagrams which generate radiatively the masses of the charged leptons. Using the experimental data we compute some bounds for the mixings parameters and for the masses of the scalars.
[ { "created": "Sat, 30 May 1998 00:09:53 GMT", "version": "v1" } ]
2009-10-31
[ [ "Cotti", "U.", "" ], [ "Gaitan", "R.", "" ], [ "Hernandez", "A.", "" ], [ "Ponce", "W.", "" ], [ "Zepeda", "A.", "" ] ]
Lepton family number violation processes arise in the $SU(6)_L \otimes U(1)_Y$ model due to the presence of an extra neutral gauge boson, Z$'$, with family changing couplings, and due to the fact that this model demands the existence of heavy exotic leptons. The mixing of the standard Z with Z$'$ and the mixing of ordinary leptons with exotic ones induce together family changing couplings on the Z and therefore nonvanishing rates for lepton family number violation processes, such as $Z \to e \bar{\mu}$, $\mu \to ee\bar{e}$ and $\mu \to e\gamma$. Additional contributions to the processes $\mu \to e \gamma$ and $\mu \to ee \bar{e}$ are induced from the mass generation mechanism. This last type of contributions may compete with the above one, depending on the masses of the scalars which participate in the diagrams which generate radiatively the masses of the charged leptons. Using the experimental data we compute some bounds for the mixings parameters and for the masses of the scalars.
1512.02201
Norimi Yokozaki
Masaki Asano, Yuichiro Nakai and Norimi Yokozaki
Low-Scale Gauge Mediation with a 100 TeV Gravitino
17 pages, 2 figures; typos corrected
Phys. Rev. D 93, 055023 (2016)
10.1103/PhysRevD.93.055023
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose a new framework of low-scale gauge-mediated supersymmetry (SUSY) breaking with a gravitino mass of O(100) TeV. The usual 4D gauge mediation models predict a light gravitino and suffer from cosmological problems. In our framework, a heavy gravitino in gauge mediation is realized with a flat extra-dimension, whose compactification scale is around the grand unified theory scale. Superparticle masses of the visible sector from gravity/anomaly mediation are suppressed, and they are purely generated by usual gauge mediation on the visible brane. Importantly, the Higgs Bmu-term vanishes at the leading order, which enables us to obtain the suitable mu-Bmu relation for the electroweak symmetry breaking. We discuss such models considering two possibilities of the SUSY breaking source: 1) Scherk-Schwarz SUSY breaking which we call Scherk-Schwarz Gauge Mediation and 2) gravitational SUSY breaking localized on a hidden brane. In the case 2), the cosmological moduli problem may be relaxed as well.
[ { "created": "Mon, 7 Dec 2015 20:37:58 GMT", "version": "v1" }, { "created": "Wed, 9 Mar 2016 09:52:16 GMT", "version": "v2" } ]
2016-03-23
[ [ "Asano", "Masaki", "" ], [ "Nakai", "Yuichiro", "" ], [ "Yokozaki", "Norimi", "" ] ]
We propose a new framework of low-scale gauge-mediated supersymmetry (SUSY) breaking with a gravitino mass of O(100) TeV. The usual 4D gauge mediation models predict a light gravitino and suffer from cosmological problems. In our framework, a heavy gravitino in gauge mediation is realized with a flat extra-dimension, whose compactification scale is around the grand unified theory scale. Superparticle masses of the visible sector from gravity/anomaly mediation are suppressed, and they are purely generated by usual gauge mediation on the visible brane. Importantly, the Higgs Bmu-term vanishes at the leading order, which enables us to obtain the suitable mu-Bmu relation for the electroweak symmetry breaking. We discuss such models considering two possibilities of the SUSY breaking source: 1) Scherk-Schwarz SUSY breaking which we call Scherk-Schwarz Gauge Mediation and 2) gravitational SUSY breaking localized on a hidden brane. In the case 2), the cosmological moduli problem may be relaxed as well.
hep-ph/0202169
Alan R. White
Alan R. White
The Chiral Anomaly and High-Energy Scattering in QCD
64 pages, 33 ps figures in the text. Version to be published
Phys.Rev. D66 (2002) 056007
10.1103/PhysRevD.66.056007
ANL-HEP-PR-02-19
hep-ph
null
Infra-red properties of the triangle anomaly and the ``anomaly pole'' are elaborated and applied to the study of high-energy scattering in QCD, when the gauge symmetry is partially broken to SU(2). It is shown that the chiral flavor anomaly provides a wee-gluon component for Goldstone bosons that combines with interactions due to the U(1) anomaly to produce an infra-red transverse momentum scaling divergence in scattering amplitudes. After the divergence is factorized out, as a wee-gluon condensate in the infinite momentum pion, the remaining physical amplitudes have confinement and chiral symmetry breaking. A lowest-order contribution to the pion scattering amplitude is calculated in detail. Although originating from very complicated diagrams, the amplitude has a remarkable (semi-)perturbative simplicity. The momentum structure is that of single gluon exchange but zero momentum quarks inject additional spin and color structure via anomaly interactions.
[ { "created": "Sun, 17 Feb 2002 21:49:54 GMT", "version": "v1" }, { "created": "Mon, 1 Apr 2002 23:40:08 GMT", "version": "v2" }, { "created": "Fri, 2 Aug 2002 16:08:01 GMT", "version": "v3" } ]
2009-11-07
[ [ "White", "Alan R.", "" ] ]
Infra-red properties of the triangle anomaly and the ``anomaly pole'' are elaborated and applied to the study of high-energy scattering in QCD, when the gauge symmetry is partially broken to SU(2). It is shown that the chiral flavor anomaly provides a wee-gluon component for Goldstone bosons that combines with interactions due to the U(1) anomaly to produce an infra-red transverse momentum scaling divergence in scattering amplitudes. After the divergence is factorized out, as a wee-gluon condensate in the infinite momentum pion, the remaining physical amplitudes have confinement and chiral symmetry breaking. A lowest-order contribution to the pion scattering amplitude is calculated in detail. Although originating from very complicated diagrams, the amplitude has a remarkable (semi-)perturbative simplicity. The momentum structure is that of single gluon exchange but zero momentum quarks inject additional spin and color structure via anomaly interactions.
hep-ph/0611286
Brian Feldstein
Brian Feldstein, Brock Tweedie
Density Perturbations in Chain Inflation
28 pages, 16 figures; v2: corrected typos, increased resolution on D=2+1 data points
JCAP 0704:020,2007
10.1088/1475-7516/2007/04/020
UCB-PTH-06/21, LBNL-62015
hep-ph
null
We consider the model of ``Chain Inflation,'' in which the period of inflation in our universe took the form of a long sequence of quantum tunneling events. We find that in the simplest such scenario, in which the tunneling processes are uniform, approximately 10^4 vacua per e-folding of inflation are required in order that the density perturbations produced are of an acceptable size. We arrive at this conclusion through a combination of analytic and numerical techniques, which could also serve as starting points for calculations with more general sets of assumptions.
[ { "created": "Wed, 22 Nov 2006 08:44:08 GMT", "version": "v1" }, { "created": "Wed, 6 Dec 2006 21:05:03 GMT", "version": "v2" } ]
2014-11-18
[ [ "Feldstein", "Brian", "" ], [ "Tweedie", "Brock", "" ] ]
We consider the model of ``Chain Inflation,'' in which the period of inflation in our universe took the form of a long sequence of quantum tunneling events. We find that in the simplest such scenario, in which the tunneling processes are uniform, approximately 10^4 vacua per e-folding of inflation are required in order that the density perturbations produced are of an acceptable size. We arrive at this conclusion through a combination of analytic and numerical techniques, which could also serve as starting points for calculations with more general sets of assumptions.
2401.05009
Preeti Bhall
Preeti Bhall and A. Upadhyay
Importance of strange sea to the charge radii and quadrupole moment of $ J^P=\frac{1}{2}^+,\frac{3}{2}^+$ baryons
null
null
null
null
hep-ph nucl-th
http://creativecommons.org/licenses/by/4.0/
A statistical framework in conjugation with the principle of detailed balance is employed to examine the low-energy properties i.e. charge radii and quadrupole moment of J$^P$=$\frac{1}{2}^+$ octet and J$^P$=$\frac{3}{2}^+$ decuplet baryon. The statistical approach assumes the expansion of baryonic system in terms of quark-gluon Fock states. We systematically apply operator formalism along with the statistical approach to study the charge radii and quadrupole moment of baryons. Based on the probabilities of all possible Fock states in spin, flavor and color space, the importance of sea with quarks and gluons is studied. The individual contribution of the constituent quarks and sea which contains terms of scalar, vector and tensor is explored. Due to large mass difference between strange and non-strange content, the SU(3) breaking effect are also investigated. The extent to which strange quark-antiquark pair is considered in sea is constrained by the mass of hadrons, the free energy of gluons in conformity with experimental indications. We focus on the individual contribution of strange and non-strange sea (g, $\langle u\bar u\rangle$, $\langle d\bar d\rangle$ and $\langle s\bar s\rangle$) accomodability in the respective hadrons for their charge radii and quadrupole moment. The present work has been compared with various theoretical approaches and some known experimental observations. Our computed results may provide important information for upcoming experimental findings.
[ { "created": "Wed, 10 Jan 2024 08:54:07 GMT", "version": "v1" } ]
2024-01-11
[ [ "Bhall", "Preeti", "" ], [ "Upadhyay", "A.", "" ] ]
A statistical framework in conjugation with the principle of detailed balance is employed to examine the low-energy properties i.e. charge radii and quadrupole moment of J$^P$=$\frac{1}{2}^+$ octet and J$^P$=$\frac{3}{2}^+$ decuplet baryon. The statistical approach assumes the expansion of baryonic system in terms of quark-gluon Fock states. We systematically apply operator formalism along with the statistical approach to study the charge radii and quadrupole moment of baryons. Based on the probabilities of all possible Fock states in spin, flavor and color space, the importance of sea with quarks and gluons is studied. The individual contribution of the constituent quarks and sea which contains terms of scalar, vector and tensor is explored. Due to large mass difference between strange and non-strange content, the SU(3) breaking effect are also investigated. The extent to which strange quark-antiquark pair is considered in sea is constrained by the mass of hadrons, the free energy of gluons in conformity with experimental indications. We focus on the individual contribution of strange and non-strange sea (g, $\langle u\bar u\rangle$, $\langle d\bar d\rangle$ and $\langle s\bar s\rangle$) accomodability in the respective hadrons for their charge radii and quadrupole moment. The present work has been compared with various theoretical approaches and some known experimental observations. Our computed results may provide important information for upcoming experimental findings.
1110.4817
Daniel Albornoz V\'asquez
Daniel Albornoz V\'asquez
Light Neutralinos in the NMSSM
3 pages, 2 figures, proceedings for The 2011 Europhysics Conference on High Energy Physics-HEP 2011
PoS(EPS-HEP2011)389
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Next-to-Minimal Supersymmetric Standard Model neutralino dark matter candidates in the (1-15) GeV range are found with a Markov Chain Monte Carlo scanning code. A very light, singlet-like Higgs and/or CP-odd Higgs is needed in order to achieve such light masses. Light scalar Higgses can yield large direct detection cross sections, suitable for an account of the recent claims for signals. Neutralino annihilations via resonant light pseudoscalar Higgs exchanges can overproduce the indirect yield of gamma-rays from dwarf spheroidal galaxies. Hence, direct and indirect detection experiments probe different configurations of the NMSSM with a light neutralino DM candidate.
[ { "created": "Fri, 21 Oct 2011 15:10:32 GMT", "version": "v1" }, { "created": "Mon, 21 Nov 2011 16:55:41 GMT", "version": "v2" } ]
2012-04-19
[ [ "Vásquez", "Daniel Albornoz", "" ] ]
Next-to-Minimal Supersymmetric Standard Model neutralino dark matter candidates in the (1-15) GeV range are found with a Markov Chain Monte Carlo scanning code. A very light, singlet-like Higgs and/or CP-odd Higgs is needed in order to achieve such light masses. Light scalar Higgses can yield large direct detection cross sections, suitable for an account of the recent claims for signals. Neutralino annihilations via resonant light pseudoscalar Higgs exchanges can overproduce the indirect yield of gamma-rays from dwarf spheroidal galaxies. Hence, direct and indirect detection experiments probe different configurations of the NMSSM with a light neutralino DM candidate.
hep-ph/0202030
Ricardo Gonzalez Felipe
G. C. Branco, R. Gonzalez Felipe, F. R. Joaquim, M. N. Rebelo
Leptogenesis, CP violation and neutrino data: What can we learn?
36 pages, 6 figures; new references added, final version to appear in Nucl. Phys. B
Nucl.Phys.B640:202-232,2002
10.1016/S0550-3213(02)00478-9
FISIST/03-2002/CFIF
hep-ph
null
A detailed analytic and numerical study of baryogenesis through leptogenesis is performed in the framework of the standard model of electroweak interactions extended by the addition of three right-handed neutrinos, leading to the seesaw mechanism. We analyze the connection between GUT-motivated relations for the quark and lepton mass matrices and the possibility of obtaining a viable leptogenesis scenario. In particular, we analyze whether the constraints imposed by SO(10) GUTs can be compatible with all the available solar, atmospheric and reactor neutrino data and, simultaneously, be capable of producing the required baryon asymmetry via the leptogenesis mechanism. It is found that the Just-So^2 and SMA solar solutions lead to a viable leptogenesis even for the simplest SO(10) GUT, while the LMA, LOW and VO solar solutions would require a different hierarchy for the Dirac neutrino masses in order to generate the observed baryon asymmetry. Some implications on CP violation at low energies and on neutrinoless double beta decay are also considered.
[ { "created": "Mon, 4 Feb 2002 21:03:46 GMT", "version": "v1" }, { "created": "Wed, 26 Jun 2002 10:39:40 GMT", "version": "v2" } ]
2011-07-19
[ [ "Branco", "G. C.", "" ], [ "Felipe", "R. Gonzalez", "" ], [ "Joaquim", "F. R.", "" ], [ "Rebelo", "M. N.", "" ] ]
A detailed analytic and numerical study of baryogenesis through leptogenesis is performed in the framework of the standard model of electroweak interactions extended by the addition of three right-handed neutrinos, leading to the seesaw mechanism. We analyze the connection between GUT-motivated relations for the quark and lepton mass matrices and the possibility of obtaining a viable leptogenesis scenario. In particular, we analyze whether the constraints imposed by SO(10) GUTs can be compatible with all the available solar, atmospheric and reactor neutrino data and, simultaneously, be capable of producing the required baryon asymmetry via the leptogenesis mechanism. It is found that the Just-So^2 and SMA solar solutions lead to a viable leptogenesis even for the simplest SO(10) GUT, while the LMA, LOW and VO solar solutions would require a different hierarchy for the Dirac neutrino masses in order to generate the observed baryon asymmetry. Some implications on CP violation at low energies and on neutrinoless double beta decay are also considered.
hep-ph/0101001
Heui-Seol Roh
Heui-Seol Roh
Quantum Weakdynamics as an SU(3)_I Gauge Theory: Grand Unification of Strong and Electroweak Interactions
REVTeX, 20 pages, corrected typographic errors, revised Section II
Eur.Phys.J.C22:359-377,2001
10.1007/s100520100803
null
hep-ph
null
Quantum weakdynamics (QWD) as an SU(3)_I gauge theory with the Theta vacuum term is considered to be the unification of the electroweak interaction as an SU(2)_L x U(1)_Y gauge theory. The grand unification of SU(3)_I x SU(3)_C beyond the standard model SU(3)_C x SU(2)_L x U(1)_Y is established by the group SU(3)_I. The grand unified interactions break down to weak and strong interactions at a new grand unification scale 10^{3} GeV, through dynamical spontaneous symmetry breaking (DSSB); the weak and strong coupling constants are the same, alpha_i = alpha_s ~ 0.12, at this scale. DSSB is realized by the condensation of scalar fields, postulated to be spatially longitudinal components of gauge bosons, instead of Higgs particles. Quark and lepton family generation, the Weinberg angle sin^2 theta_W = 1/4, and the Cabbibo angle sin theta_C = 1/4 are predicted. The electroweak coupling constants are alpha_z = alpha_i/3, alpha_w = alpha_i/4, alpha_y = alpha_i/12, and alpha_e = alpha_i/16 = 1/137; there are symmetric isospin interactions.
[ { "created": "Sat, 30 Dec 2000 05:03:29 GMT", "version": "v1" }, { "created": "Thu, 10 Jan 2002 07:10:21 GMT", "version": "v2" } ]
2008-11-26
[ [ "Roh", "Heui-Seol", "" ] ]
Quantum weakdynamics (QWD) as an SU(3)_I gauge theory with the Theta vacuum term is considered to be the unification of the electroweak interaction as an SU(2)_L x U(1)_Y gauge theory. The grand unification of SU(3)_I x SU(3)_C beyond the standard model SU(3)_C x SU(2)_L x U(1)_Y is established by the group SU(3)_I. The grand unified interactions break down to weak and strong interactions at a new grand unification scale 10^{3} GeV, through dynamical spontaneous symmetry breaking (DSSB); the weak and strong coupling constants are the same, alpha_i = alpha_s ~ 0.12, at this scale. DSSB is realized by the condensation of scalar fields, postulated to be spatially longitudinal components of gauge bosons, instead of Higgs particles. Quark and lepton family generation, the Weinberg angle sin^2 theta_W = 1/4, and the Cabbibo angle sin theta_C = 1/4 are predicted. The electroweak coupling constants are alpha_z = alpha_i/3, alpha_w = alpha_i/4, alpha_y = alpha_i/12, and alpha_e = alpha_i/16 = 1/137; there are symmetric isospin interactions.
2008.02895
Tianbo Liu
Tianbo Liu, W. Melnitchouk, Jian-Wei Qiu, N. Sato
Factorized approach to radiative corrections for inelastic lepton-hadron collisions
6 pages, 3 figures, accepted for publication in Phys. Rev. D
null
10.1103/PhysRevD.104.094033
JLAB-THY-20-3233
hep-ph hep-ex nucl-ex nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose a factorized approach to QED radiative corrections for inclusive and semi-inclusive deep-inelastic scattering to systematically account for QED and QCD radiation contributions to both processes on equal footing. This is achieved by utilizing factorization to resum logarithmically enhanced QED radiation into universal lepton distribution and fragmentation (or jet) functions. Numerical simulations suggest that the QED effects induced by the rotational distortion of the hadron transverse momentum, arising from the mismatch between the experimental Breit frame and the true photon-hadron frame, can be as large as 50\% for moderate $Q$, and become increasingly important for large transverse momenta. Our framework provides a uniform treatment of radiative effects for extracting three-dimensional hadron structure from high-energy lepton-hadron scattering at current and future facilities, such as the Electron-Ion Collider.
[ { "created": "Thu, 6 Aug 2020 22:27:09 GMT", "version": "v1" }, { "created": "Mon, 14 Sep 2020 16:15:26 GMT", "version": "v2" }, { "created": "Wed, 17 Mar 2021 14:27:53 GMT", "version": "v3" }, { "created": "Thu, 11 Nov 2021 14:12:28 GMT", "version": "v4" } ]
2021-12-01
[ [ "Liu", "Tianbo", "" ], [ "Melnitchouk", "W.", "" ], [ "Qiu", "Jian-Wei", "" ], [ "Sato", "N.", "" ] ]
We propose a factorized approach to QED radiative corrections for inclusive and semi-inclusive deep-inelastic scattering to systematically account for QED and QCD radiation contributions to both processes on equal footing. This is achieved by utilizing factorization to resum logarithmically enhanced QED radiation into universal lepton distribution and fragmentation (or jet) functions. Numerical simulations suggest that the QED effects induced by the rotational distortion of the hadron transverse momentum, arising from the mismatch between the experimental Breit frame and the true photon-hadron frame, can be as large as 50\% for moderate $Q$, and become increasingly important for large transverse momenta. Our framework provides a uniform treatment of radiative effects for extracting three-dimensional hadron structure from high-energy lepton-hadron scattering at current and future facilities, such as the Electron-Ion Collider.
1307.1221
Krishna Kingkar Pathak
Krishna Kingkar Pathak and D K Choudhury
Semileptonic decay of $B_c$ meson into $c\bar c$ states in a QCD potential model
We are presently improving the manuscript
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The slope and curvature of Isgur Wise function for $B_{c}$ meson is computed in a QCD potential model in two different approaches of choosing the perturbative term of the Cornell potential. Based on heavy quark effective theory the exclusive semileptonic decay rates of $B_c$ meson into the $c\bar c\ (\eta_c,J/\psi)$ states are exploited. Spin symmetry breaking effects are ignored upto a particular point and the form factors are connected with Isgur-Wise function for other kinematic point since the recoil momentum of $c\bar c$ from $B_{c}$ is small due to its heavy mass.
[ { "created": "Thu, 4 Jul 2013 06:45:19 GMT", "version": "v1" }, { "created": "Mon, 5 Dec 2022 16:53:30 GMT", "version": "v2" } ]
2022-12-06
[ [ "Pathak", "Krishna Kingkar", "" ], [ "Choudhury", "D K", "" ] ]
The slope and curvature of Isgur Wise function for $B_{c}$ meson is computed in a QCD potential model in two different approaches of choosing the perturbative term of the Cornell potential. Based on heavy quark effective theory the exclusive semileptonic decay rates of $B_c$ meson into the $c\bar c\ (\eta_c,J/\psi)$ states are exploited. Spin symmetry breaking effects are ignored upto a particular point and the form factors are connected with Isgur-Wise function for other kinematic point since the recoil momentum of $c\bar c$ from $B_{c}$ is small due to its heavy mass.
1206.1453
George W. S. Hou
Wei-Shu Hou
Heavy QQ(bar) "Fireball" Annihilation to Multiple Vector Bosons
4 pages, 1 figure
null
10.1103/PhysRevD.86.037701
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Drawing analogy of replacing the nucleon by heavy chiral quark $Q$, the pion by Goldstone boson $G$, and $\pi NN$ coupling by $GQQ$ coupling, we construct a statistical model for $Q\bar Q \to nG$ annihilation, i.e. into $n$ longitudinal weak bosons. This analogy is becoming prescient since the LHC direct bound $m_Q > 611$ GeV implies strong Yukawa coupling. Taking $m_Q \in (1, 2)$ TeV, the mean number $<n_G>$ ranges from 6 to over 10, with negligible two or three boson production. With individual $t'$ or $b'$ decays suppressed either by phase space or quark mixing, and given the strong Yukawa coupling, $Q\bar Q\to nV_L$ is the likely outcome for very heavy $Q\bar Q$ production at the LHC.
[ { "created": "Thu, 7 Jun 2012 11:21:46 GMT", "version": "v1" } ]
2013-05-30
[ [ "Hou", "Wei-Shu", "" ] ]
Drawing analogy of replacing the nucleon by heavy chiral quark $Q$, the pion by Goldstone boson $G$, and $\pi NN$ coupling by $GQQ$ coupling, we construct a statistical model for $Q\bar Q \to nG$ annihilation, i.e. into $n$ longitudinal weak bosons. This analogy is becoming prescient since the LHC direct bound $m_Q > 611$ GeV implies strong Yukawa coupling. Taking $m_Q \in (1, 2)$ TeV, the mean number $<n_G>$ ranges from 6 to over 10, with negligible two or three boson production. With individual $t'$ or $b'$ decays suppressed either by phase space or quark mixing, and given the strong Yukawa coupling, $Q\bar Q\to nV_L$ is the likely outcome for very heavy $Q\bar Q$ production at the LHC.
hep-ph/9711435
Marco Aurelio Diaz
Marco Aurelio Diaz
The Minimal Supersymmetric Standard Model with a Bilinear R--Parity Violating Term
12 pages including 10 figures, Latex. Talk given at the International Workshop on Quantum Effects in the MSSM, 9--13 Sep. 1997, Barcelona, Spain
null
null
IFIC/97-87, FTUV/97-57
hep-ph
null
Some aspects of bilinear R-Parity violation, the simplest extension of the MSSM which does not conserve R-Parity, are reviewed in comparison with the MSSM. We put special emphasis on the effect of quantum corrections.
[ { "created": "Mon, 24 Nov 1997 12:59:24 GMT", "version": "v1" } ]
2007-05-23
[ [ "Diaz", "Marco Aurelio", "" ] ]
Some aspects of bilinear R-Parity violation, the simplest extension of the MSSM which does not conserve R-Parity, are reviewed in comparison with the MSSM. We put special emphasis on the effect of quantum corrections.
hep-ph/9802251
Shaouly Bar-Shalom
S. Bar-Shalom, G. Eilam and A. Soni
R-parity violation and CP-violating and CP-conserving spin asymmetries in l^+ l^- -> sneutrino -> tau^+ tau^-: probing sneutrino mixing at LEP2, NLC and mu^+mu^- colliders
12 pages, plain latex, 3 figures embadded in the text using epsfig
Phys. Rev. D 59, 055012 (1999)
10.1103/PhysRevLett.80.4629
UCRHEP-T215
hep-ph
null
We consider the sneutrino resonance reaction l^+ l^- -> sneutrino -> tau^+ tau^- in the MSSM without R-parity. We introduce new CP-violating and CP-conserving tau-spin asymmetries which are generated already at the tree-level if there is sneutrino - sneutrino-bar mixing and that are forbidden in the SM. It is remarkable that these spin asymmetries can reach ~75% around resonance for a sneutrino mass splitting of \Delta m ~ \Gamma and ~10% for a splitting as low as \Delta m ~ 0.1\Gamma, where \Gamma is the sneutrino width. We show that they are easily detectable already at LEP2 so long as the beam energy is within ~10 GeV range around the muon-sneutrino masses and may therefore serve as extremely powerful probes of sneutrino mixing phenomena.
[ { "created": "Thu, 5 Feb 1998 01:25:13 GMT", "version": "v1" } ]
2016-08-25
[ [ "Bar-Shalom", "S.", "" ], [ "Eilam", "G.", "" ], [ "Soni", "A.", "" ] ]
We consider the sneutrino resonance reaction l^+ l^- -> sneutrino -> tau^+ tau^- in the MSSM without R-parity. We introduce new CP-violating and CP-conserving tau-spin asymmetries which are generated already at the tree-level if there is sneutrino - sneutrino-bar mixing and that are forbidden in the SM. It is remarkable that these spin asymmetries can reach ~75% around resonance for a sneutrino mass splitting of \Delta m ~ \Gamma and ~10% for a splitting as low as \Delta m ~ 0.1\Gamma, where \Gamma is the sneutrino width. We show that they are easily detectable already at LEP2 so long as the beam energy is within ~10 GeV range around the muon-sneutrino masses and may therefore serve as extremely powerful probes of sneutrino mixing phenomena.