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hep-ph/0109124
Seiichi Wakaizumi
T. Hattori (Univ of Tokushima), T. Hasuike (Anan Col of Technology), S. Wakaizumi (Univ of Tokushima)
CP violation and matter effect in long-baseline neutrino oscillation in the four-neutrino model
29 pages, 12 eps figures. We have shown the dependence of the CP violation effects on various parameters, discussed about the relation between the active-sterile neutrino admixture and the effects in both Tables and Figures, and added some references to the published works
Phys.Rev.D65:073027,2002
10.1103/PhysRevD.65.073027
null
hep-ph
null
We investigate the CP violation effect and the matter effect in the long-baseline neutrino oscillations in the four-neutrino model with mass scheme of the two pairs of two close masses separated by a gap of the order of 1 eV by using the constraints on the mixing matrix derived from the solar neutrino deficit, atmospheric neutrino anomaly, LSND experiments, and the other terrestrial neutrino oscillation experiments. We also use the results of the combined analyses by Gonzalez-Garcia, Maltoni, and Pe\~na-Garay of the solutions to the solar and atmospheric neutrino problems with the recent SNO solar neutrino data. For the solution of close-to-active solar neutrino oscillations plus close-to-sterile atmospheric neutrino oscillations, the pure CP violation part of the oscillation probability difference between the CP-conjugate channels could attain as large as $0.10-0.25$ in the neutrino energy range of $E = 6-15$ GeV at the baseline $L = 730$ km for $\nu_\mu\to\nu_\tau$ oscillation, and the matter effect is at the $8-15%$ level of the pure CP violation effect, while for the solution of near-pure-sterile solar neutrino oscillations plus near-pure-active atmospheric neutrino oscillations, the pure CP violation effect in $\Delta P(\nu_\mu\to\nu_\tau)$ is very small $(\sim 0.01)$ and is comparable to the matter effect. For $\nu_\mu\to\nu_e$ oscillation, the pure CP violation effect is independent of the active-sterile admixture and is at most 0.05 in $E = 1.5-3$ GeV at $L = 290$ km and the matter effect is at the $15-30%$ level.
[ { "created": "Fri, 14 Sep 2001 10:00:31 GMT", "version": "v1" }, { "created": "Mon, 24 Dec 2001 03:09:31 GMT", "version": "v2" } ]
2014-11-17
[ [ "Hattori", "T.", "", "Univ of Tokushima" ], [ "Hasuike", "T.", "", "Anan Col of Technology" ], [ "Wakaizumi", "S.", "", "Univ of Tokushima" ] ]
We investigate the CP violation effect and the matter effect in the long-baseline neutrino oscillations in the four-neutrino model with mass scheme of the two pairs of two close masses separated by a gap of the order of 1 eV by using the constraints on the mixing matrix derived from the solar neutrino deficit, atmospheric neutrino anomaly, LSND experiments, and the other terrestrial neutrino oscillation experiments. We also use the results of the combined analyses by Gonzalez-Garcia, Maltoni, and Pe\~na-Garay of the solutions to the solar and atmospheric neutrino problems with the recent SNO solar neutrino data. For the solution of close-to-active solar neutrino oscillations plus close-to-sterile atmospheric neutrino oscillations, the pure CP violation part of the oscillation probability difference between the CP-conjugate channels could attain as large as $0.10-0.25$ in the neutrino energy range of $E = 6-15$ GeV at the baseline $L = 730$ km for $\nu_\mu\to\nu_\tau$ oscillation, and the matter effect is at the $8-15%$ level of the pure CP violation effect, while for the solution of near-pure-sterile solar neutrino oscillations plus near-pure-active atmospheric neutrino oscillations, the pure CP violation effect in $\Delta P(\nu_\mu\to\nu_\tau)$ is very small $(\sim 0.01)$ and is comparable to the matter effect. For $\nu_\mu\to\nu_e$ oscillation, the pure CP violation effect is independent of the active-sterile admixture and is at most 0.05 in $E = 1.5-3$ GeV at $L = 290$ km and the matter effect is at the $15-30%$ level.
1211.3408
Christopher Wever
Pietro Falgari, Christian Schwinn, Christopher Wever
Finite-width effects on threshold corrections to squark and gluino production
30 pages, 13 figures. v2: minor typos corrected and clarifications added
null
10.1007/JHEP01(2013)085
ITP-UU-12/37; SPIN-12/34; FR-PHENO-2012-33
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the implication of finite squark and gluino decay widths for threshold resummation of squark and gluino production cross sections at the LHC. We find that for a moderate decay width (Gamma/m < 5%) higher-order soft and Coulomb corrections are appropriately described by NLL calculations in the zero-width limit including the contribution from bound-state resonances below threshold, with the remaining uncertainties due to finite-width effects of a similar order as the ambiguities of threshold-resummed higher-order calculations.
[ { "created": "Wed, 14 Nov 2012 20:33:21 GMT", "version": "v1" }, { "created": "Tue, 27 Nov 2012 17:54:12 GMT", "version": "v2" } ]
2015-06-12
[ [ "Falgari", "Pietro", "" ], [ "Schwinn", "Christian", "" ], [ "Wever", "Christopher", "" ] ]
We study the implication of finite squark and gluino decay widths for threshold resummation of squark and gluino production cross sections at the LHC. We find that for a moderate decay width (Gamma/m < 5%) higher-order soft and Coulomb corrections are appropriately described by NLL calculations in the zero-width limit including the contribution from bound-state resonances below threshold, with the remaining uncertainties due to finite-width effects of a similar order as the ambiguities of threshold-resummed higher-order calculations.
hep-ph/0402046
Cristian Pisano
A. Mukherjee, C. Pisano
Suppressing the Background Process to QED Compton Scattering for Delineating the Photon Content of the Proton
Minor changes in the text, 2 figures changed, results unchanged
Eur.Phys.J.C35:509-517,2004
10.1140/epjc/s2004-01822-5
DO-TH 03/19
hep-ph hep-ex
null
We investigate the QED Compton process (QEDCS) in $e p \to e \gamma p$ and $e p \to e \gamma X$, together with the major background coming from the virtual Compton scattering (VCS), where the photon is emitted from the hadronic vertex. We suggest new kinematical constraints which suppress the VCS background and are furthermore suitable for the extraction of the equivalent photon content of the proton at the HERA collider. We show that the cross section, commonly expressed in terms of the proton structure functions, is reasonably well described by the equivalent photon approximation of the proton, also in the inelastic channel in the proposed kinematical region.
[ { "created": "Wed, 4 Feb 2004 14:52:43 GMT", "version": "v1" }, { "created": "Mon, 8 Mar 2004 17:02:29 GMT", "version": "v2" } ]
2009-04-15
[ [ "Mukherjee", "A.", "" ], [ "Pisano", "C.", "" ] ]
We investigate the QED Compton process (QEDCS) in $e p \to e \gamma p$ and $e p \to e \gamma X$, together with the major background coming from the virtual Compton scattering (VCS), where the photon is emitted from the hadronic vertex. We suggest new kinematical constraints which suppress the VCS background and are furthermore suitable for the extraction of the equivalent photon content of the proton at the HERA collider. We show that the cross section, commonly expressed in terms of the proton structure functions, is reasonably well described by the equivalent photon approximation of the proton, also in the inelastic channel in the proposed kinematical region.
2301.02366
Sumit Satapathy
Sumit Satapathy
Discussion on Inert Doublet Model and loop correction of $HH\to hh$
null
null
10.6084/m9.figshare.21816324
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We take the Lagrangian of Inert Doublet Model and with unitary gauge calculate all the possible interactions, after calculating the interactions we draw the corresponding Feynman diagrams.There after calculate the Scattering cross section of the processes that contribute in the decay or scattering of DM candidate. In the concluding chapter we calculate the one loop correction to the process $HH\to hh$ and see all the possible loop contribution at this scale.
[ { "created": "Fri, 6 Jan 2023 04:15:38 GMT", "version": "v1" }, { "created": "Wed, 11 Jan 2023 04:37:33 GMT", "version": "v2" }, { "created": "Thu, 12 Jan 2023 07:04:03 GMT", "version": "v3" } ]
2023-01-13
[ [ "Satapathy", "Sumit", "" ] ]
We take the Lagrangian of Inert Doublet Model and with unitary gauge calculate all the possible interactions, after calculating the interactions we draw the corresponding Feynman diagrams.There after calculate the Scattering cross section of the processes that contribute in the decay or scattering of DM candidate. In the concluding chapter we calculate the one loop correction to the process $HH\to hh$ and see all the possible loop contribution at this scale.
0712.0732
Charles Gale
Simon Turbide, Charles Gale, Evan Frodermann, Ulrich Heinz
Electromagnetic radiation from nuclear collisions at RHIC energies
null
Phys.Rev.C77:024909,2008
10.1103/PhysRevC.77.024909
CERN-PH-TH/2007-239
hep-ph nucl-th
null
The hot and dense strongly interacting matter created in collisions of heavy nuclei at RHIC energies is modeled with relativistic hydrodynamics, and the spectra of real and virtual photons produced at mid-rapidity in these events are calculated. Several different sources are considered, and their relative importance is compared. Specifically, we include jet fragmentation, jet-plasma interactions, the emission of radiation from the thermal medium and from primordial hard collisions. Our calculations consistently take into account jet energy loss, as evaluated in the AMY formalism. We obtain results for the spectra, the nuclear modification factor (R_AA), and the azimuthal anisotropy (v_2) that agree with the photon measurements performed by the PHENIX collaboration at RHIC.
[ { "created": "Wed, 5 Dec 2007 15:08:18 GMT", "version": "v1" }, { "created": "Thu, 20 Dec 2007 20:45:45 GMT", "version": "v2" } ]
2008-11-26
[ [ "Turbide", "Simon", "" ], [ "Gale", "Charles", "" ], [ "Frodermann", "Evan", "" ], [ "Heinz", "Ulrich", "" ] ]
The hot and dense strongly interacting matter created in collisions of heavy nuclei at RHIC energies is modeled with relativistic hydrodynamics, and the spectra of real and virtual photons produced at mid-rapidity in these events are calculated. Several different sources are considered, and their relative importance is compared. Specifically, we include jet fragmentation, jet-plasma interactions, the emission of radiation from the thermal medium and from primordial hard collisions. Our calculations consistently take into account jet energy loss, as evaluated in the AMY formalism. We obtain results for the spectra, the nuclear modification factor (R_AA), and the azimuthal anisotropy (v_2) that agree with the photon measurements performed by the PHENIX collaboration at RHIC.
2112.00137
Matthew Smylie
Linda M. Carpenter, Matthew J. Smylie, Jesus Manuel Caridad Ramirez, Cameron McDowell, and Daniel Whiteson
New physics in triboson event topologies
21 pages, 13 figures. Updated to match the version of record
Phys. Rev. D 105, 075027 (2022)
10.1103/PhysRevD.105.075027
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a study of the sensitivity to models of new physics of proton collisions resulting in three electroweak bosons. As a benchmark, we analyze models in which an exotic scalar field $\phi$ is produced in association with a gauge boson ($V=\gamma$ or $Z$). The scalar then decays to a pair of bosons, giving the process $pp\rightarrow \phi V\rightarrow V'V"V$. We interpret our results in a set of effective field theories where the exotic scalar fields couple to the Standard Model through pairs of electroweak gauge bosons. We estimate the sensitivity of the LHC and HL-LHC datasets and find sensitivity to cross sections in the 10 fb -- 0.5 fb range, corresponding to scalar masses of 500 GeV to 2 TeV and effective operator coefficients up to 35 TeV.
[ { "created": "Tue, 30 Nov 2021 22:16:47 GMT", "version": "v1" }, { "created": "Fri, 29 Apr 2022 18:43:54 GMT", "version": "v2" } ]
2022-05-03
[ [ "Carpenter", "Linda M.", "" ], [ "Smylie", "Matthew J.", "" ], [ "Ramirez", "Jesus Manuel Caridad", "" ], [ "McDowell", "Cameron", "" ], [ "Whiteson", "Daniel", "" ] ]
We present a study of the sensitivity to models of new physics of proton collisions resulting in three electroweak bosons. As a benchmark, we analyze models in which an exotic scalar field $\phi$ is produced in association with a gauge boson ($V=\gamma$ or $Z$). The scalar then decays to a pair of bosons, giving the process $pp\rightarrow \phi V\rightarrow V'V"V$. We interpret our results in a set of effective field theories where the exotic scalar fields couple to the Standard Model through pairs of electroweak gauge bosons. We estimate the sensitivity of the LHC and HL-LHC datasets and find sensitivity to cross sections in the 10 fb -- 0.5 fb range, corresponding to scalar masses of 500 GeV to 2 TeV and effective operator coefficients up to 35 TeV.
2404.13889
Wen-long Sang
Xiao-Wei Bai, Feng Feng, Chang-Man Gan, Yingsheng Huang, Wen-Long Sang, Hong-Fei Zhang
Producing Fully-Charmed Tetraquarks via Charm Quark Fragmentation in Colliders
17 pages, 2 figures, 5 tables
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Within the framework of nonrelativistic QCD (NRQCD), we calculate the fragmentation function for a charm quark into an $S$-wave fully-charmed tetraquark, denoted as $T_{4c}$. The charm-to-$T_{4c}$ fragmentation function can be expressed as a sum of products of the perturbatively calculable short-distance coefficients and the nonperturbative long-distance matrix elements. The short-distance coefficients are ascertained through the perturbative matching procedure at lowest order in $\alpha_{s}$ and $v$ expansion. Incorporating the celebrated QCD factorization and the charm-to-$T_{4c}$ fragmentation function, we are able to predict the $T_{4c}$ production rate at high transverse momentum $p_T$ in colliders. In phenomenology, we approximate the NRQCD matrix elements with phenomenological four-body wave functions at the origin. After applying appropriate kinematic constraints, both the differential distribution over $p_T$ and the integrated cross sections are predicted at the \texttt{LHC}. The cross section can reach approximately $100$ fb, indicating the potential for a significant number of $T_{4c}$ events to be produced at the \texttt{LHC}. Additionally, we provide predictions for the photoproduction of $T_{4c}$ in electron-proton ($ep$) collisions. However, it is observed that the cross sections for these processes are relatively small at the \texttt{HERA}, \texttt{EIC} as well as \texttt{EicC}. Given these findings, the prospect of detecting these fully heavy tetraquarks at $ep$ colliders appears to be rather challenging.
[ { "created": "Mon, 22 Apr 2024 05:32:10 GMT", "version": "v1" } ]
2024-04-23
[ [ "Bai", "Xiao-Wei", "" ], [ "Feng", "Feng", "" ], [ "Gan", "Chang-Man", "" ], [ "Huang", "Yingsheng", "" ], [ "Sang", "Wen-Long", "" ], [ "Zhang", "Hong-Fei", "" ] ]
Within the framework of nonrelativistic QCD (NRQCD), we calculate the fragmentation function for a charm quark into an $S$-wave fully-charmed tetraquark, denoted as $T_{4c}$. The charm-to-$T_{4c}$ fragmentation function can be expressed as a sum of products of the perturbatively calculable short-distance coefficients and the nonperturbative long-distance matrix elements. The short-distance coefficients are ascertained through the perturbative matching procedure at lowest order in $\alpha_{s}$ and $v$ expansion. Incorporating the celebrated QCD factorization and the charm-to-$T_{4c}$ fragmentation function, we are able to predict the $T_{4c}$ production rate at high transverse momentum $p_T$ in colliders. In phenomenology, we approximate the NRQCD matrix elements with phenomenological four-body wave functions at the origin. After applying appropriate kinematic constraints, both the differential distribution over $p_T$ and the integrated cross sections are predicted at the \texttt{LHC}. The cross section can reach approximately $100$ fb, indicating the potential for a significant number of $T_{4c}$ events to be produced at the \texttt{LHC}. Additionally, we provide predictions for the photoproduction of $T_{4c}$ in electron-proton ($ep$) collisions. However, it is observed that the cross sections for these processes are relatively small at the \texttt{HERA}, \texttt{EIC} as well as \texttt{EicC}. Given these findings, the prospect of detecting these fully heavy tetraquarks at $ep$ colliders appears to be rather challenging.
hep-ph/9908314
Gregory W. Carter
G.W. Carter and D. Diakonov
Instanton-Induced Interactions in Finite Density QCD
4 pages, 5 figures, uses espcrc1.sty. To appear in Proceedings of Quark Matter 99 (10-14 May 1999, Torino, Italy) and PANIC 99 (10-16 June 1999, Uppsala, Sweden)
Nucl.Phys. A661 (1999) 625; Nucl.Phys. A663 (2000) 741-744
10.1016/S0375-9474(99)00708-3
null
hep-ph
null
We consider the finite density, zero-temperature behaviour of quark matter in the instanton picture. Since the instanton-induced interactions are attractive in both $\bar{q}q$ and $qq$ channels, a competition ensues between phases of matter with condensation in either or both. It results in chiral symmetry restoration due to the onset of diquark condensation, a `colour superconductor', at finite density.
[ { "created": "Tue, 10 Aug 1999 09:27:20 GMT", "version": "v1" } ]
2009-10-31
[ [ "Carter", "G. W.", "" ], [ "Diakonov", "D.", "" ] ]
We consider the finite density, zero-temperature behaviour of quark matter in the instanton picture. Since the instanton-induced interactions are attractive in both $\bar{q}q$ and $qq$ channels, a competition ensues between phases of matter with condensation in either or both. It results in chiral symmetry restoration due to the onset of diquark condensation, a `colour superconductor', at finite density.
0810.2807
Ivan Vitev
Ivan Vitev, Simon Wicks, Ben-Wei Zhang
A theory of jet shapes and cross sections: from hadrons to nuclei
20 pages, 15 ps and eps figures
JHEP 0811:093,2008
10.1088/1126-6708/2008/11/093
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
For jets, with great power comes great opportunity. The unprecedented center of mass energies available at the LHC open new windows on the QGP: we demonstrate that jet shape and jet cross section measurements become feasible as a new, differential and accurate test of the underlying QCD theory. We present a first step in understanding these shapes and cross sections in heavy ion reactions. Our approach allows for detailed simulations of the experimental acceptance/cuts that help isolate jets in such high-multiplicity environment. It is demonstrated for the first time that the pattern of stimulated gluon emission can be correlated with a variable quenching of the jet rates and provide an approximately model-independent approach to determining the characteristics of the medium-induced bremsstrahlung spectrum. Surprisingly, in realistic simulations of parton propagation through the QGP we find a minimal increase in the mean jet radius even for large jet attenuation. Jet broadening is manifest in the tails of the energy distribution away from the jet axis and its quantification requires high statistics measurements that will be possible at the LHC.
[ { "created": "Wed, 15 Oct 2008 21:28:44 GMT", "version": "v1" } ]
2009-05-20
[ [ "Vitev", "Ivan", "" ], [ "Wicks", "Simon", "" ], [ "Zhang", "Ben-Wei", "" ] ]
For jets, with great power comes great opportunity. The unprecedented center of mass energies available at the LHC open new windows on the QGP: we demonstrate that jet shape and jet cross section measurements become feasible as a new, differential and accurate test of the underlying QCD theory. We present a first step in understanding these shapes and cross sections in heavy ion reactions. Our approach allows for detailed simulations of the experimental acceptance/cuts that help isolate jets in such high-multiplicity environment. It is demonstrated for the first time that the pattern of stimulated gluon emission can be correlated with a variable quenching of the jet rates and provide an approximately model-independent approach to determining the characteristics of the medium-induced bremsstrahlung spectrum. Surprisingly, in realistic simulations of parton propagation through the QGP we find a minimal increase in the mean jet radius even for large jet attenuation. Jet broadening is manifest in the tails of the energy distribution away from the jet axis and its quantification requires high statistics measurements that will be possible at the LHC.
1604.07776
Sho Iwamoto
Sho Iwamoto, Gabriel Lee, Yael Shadmi, Robert Ziegler
Diphoton Signals from Colorless Hidden Quarkonia
8 pages, 4 figures; Eq. 23 corrected (the constraint relaxed by a factor ~6); version to appear in PRD
Phys. Rev. D 94, 015003 (2016)
10.1103/PhysRevD.94.015003
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We show that quarkonia-like states of a hidden SU(N) gauge group can account for the 750 GeV diphoton excess observed by ATLAS and CMS, even with constituents carrying standard model hypercharge only. The required hypercharge is modest, varying between about 1.3-1.6 for strong SU(N) coupling, to 2-3 for weak SU(N) coupling, for N=3, 4. This scenario predicts a variety of diphoton and multi-photon resonances, as well as photons from continuum pair production, and possibly exotic decays into standard model fermions, with no multi-jet resonances.
[ { "created": "Tue, 26 Apr 2016 18:03:45 GMT", "version": "v1" }, { "created": "Thu, 28 Apr 2016 18:13:42 GMT", "version": "v2" }, { "created": "Tue, 3 May 2016 19:36:49 GMT", "version": "v3" }, { "created": "Fri, 24 Jun 2016 19:26:17 GMT", "version": "v4" } ]
2016-07-13
[ [ "Iwamoto", "Sho", "" ], [ "Lee", "Gabriel", "" ], [ "Shadmi", "Yael", "" ], [ "Ziegler", "Robert", "" ] ]
We show that quarkonia-like states of a hidden SU(N) gauge group can account for the 750 GeV diphoton excess observed by ATLAS and CMS, even with constituents carrying standard model hypercharge only. The required hypercharge is modest, varying between about 1.3-1.6 for strong SU(N) coupling, to 2-3 for weak SU(N) coupling, for N=3, 4. This scenario predicts a variety of diphoton and multi-photon resonances, as well as photons from continuum pair production, and possibly exotic decays into standard model fermions, with no multi-jet resonances.
0901.0522
Alexander Tarakanov
A.V. Filatov, S.A. Smolyansky, A.V. Tarakanov (Physical Department of Saratov State University)
Kinetics of parton- antiparton plasma vacuum creation in the time - dependent chromo - electric fields of arbitrary polarization
6 pages, XIX Baldin International Seminar on High Energy Physics Problems "Relativistic Nuclear Physics and Quantum Chromodynamics"
null
null
null
hep-ph
http://creativecommons.org/licenses/by/3.0/
The kinetic equation of non - Markovian type for description of the vacuum creation of parton - antiparton pairs under action of a space homogeneous time - dependent chromo - electric field of the arbitrary polarization is obtained on the strict non - pertubative foundation in the framework of the oscillator representation. A comparison of the effectiveness of vacuum creation with the case of linear polarization one is fulfilled.
[ { "created": "Mon, 5 Jan 2009 17:05:20 GMT", "version": "v1" } ]
2009-01-06
[ [ "Filatov", "A. V.", "", "Physical Department of\n Saratov State University" ], [ "Smolyansky", "S. A.", "", "Physical Department of\n Saratov State University" ], [ "Tarakanov", "A. V.", "", "Physical Department of\n Saratov State University" ] ]
The kinetic equation of non - Markovian type for description of the vacuum creation of parton - antiparton pairs under action of a space homogeneous time - dependent chromo - electric field of the arbitrary polarization is obtained on the strict non - pertubative foundation in the framework of the oscillator representation. A comparison of the effectiveness of vacuum creation with the case of linear polarization one is fulfilled.
0806.0538
Florian Staub
F. Staub
Sarah
Manual of Version 3.2.0 of the Mathematica Package SARAH. The current version of the package can be download from http://sarah.hepforge.org/
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
SARAH is a Mathematica package for building and analyzing supersymmetric models. SARAH just needs the gauge structure, particle content and superpotential to produce all information about the gauge eigenstates of a model. Breaking of gauge symmetries and mixings of particles can easily be in a second step and entire Lagrangian is derived automatically. Also the gauge fixing terms are derived by SARAH in R_Xi gauge, and the corresponding ghost interactions are calculated. Using this information, SARAH can calculate the all mass matrices, tadpole equations and vertices at tree-level for the given model. In addition, the expressions for the 1- and 2-loop renormalization group equations of all parameters can be calculated and an automatic calculation for the 1-loop corrections to self energies and the tadpoles are possible. SARAH can write all information about the model to LaTeX files, or create a model files for FeynArts/FormCalc, WHIZARD/OMEGA and CalcHep/CompHep, which can also be used for dark matter studies using MicrOmegas, and in the UFO format which is supported by MadGraph 5. Beginning with version 3, SARAH is also the first available spectrum-generator-generator: based on the derived, analytical expression it creates source code for SPheno to calculate the mass spectrum as well the SUSY decays with high precision. In that way, it is possible to implement new models in SPheno without the need to write any Fortran code by hand. Already many models beyond the MSSM are included in the public version of SARAH and the implementation of new models is easy and straightforward.
[ { "created": "Tue, 3 Jun 2008 13:36:09 GMT", "version": "v1" }, { "created": "Wed, 4 Jun 2008 08:40:01 GMT", "version": "v2" }, { "created": "Fri, 28 Aug 2009 07:34:02 GMT", "version": "v3" }, { "created": "Wed, 3 Feb 2010 14:56:18 GMT", "version": "v4" }, { "crea...
2012-11-07
[ [ "Staub", "F.", "" ] ]
SARAH is a Mathematica package for building and analyzing supersymmetric models. SARAH just needs the gauge structure, particle content and superpotential to produce all information about the gauge eigenstates of a model. Breaking of gauge symmetries and mixings of particles can easily be in a second step and entire Lagrangian is derived automatically. Also the gauge fixing terms are derived by SARAH in R_Xi gauge, and the corresponding ghost interactions are calculated. Using this information, SARAH can calculate the all mass matrices, tadpole equations and vertices at tree-level for the given model. In addition, the expressions for the 1- and 2-loop renormalization group equations of all parameters can be calculated and an automatic calculation for the 1-loop corrections to self energies and the tadpoles are possible. SARAH can write all information about the model to LaTeX files, or create a model files for FeynArts/FormCalc, WHIZARD/OMEGA and CalcHep/CompHep, which can also be used for dark matter studies using MicrOmegas, and in the UFO format which is supported by MadGraph 5. Beginning with version 3, SARAH is also the first available spectrum-generator-generator: based on the derived, analytical expression it creates source code for SPheno to calculate the mass spectrum as well the SUSY decays with high precision. In that way, it is possible to implement new models in SPheno without the need to write any Fortran code by hand. Already many models beyond the MSSM are included in the public version of SARAH and the implementation of new models is easy and straightforward.
1512.03311
Albert Renau Cerrillo
Albert Renau
Some theoretical and experimental aspects of axion physics
144 pages, PhD thesis, University of Barcelona, Nov 2015
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In the first part of the thesis, we revisit the Dine-Fischler-Srednicki-Zhitnisky axion model in light of the recent Higgs LHC results and electroweak precision data. This model is an extension of the two-Higgs-doublet model incorporating a PQ symmetry which leads to a physically acceptable axion. For generic values of the couplings, the model reproduces the minimal Standard Model, with a massless axion and all the other degrees of freedom at a very high scale. However, in some scenarios, the extra Higgses could be relatively light. We use the oblique corrections, in particular $\Delta\rho$, to constrain the mass spectrum in this case. Finally, we also work out the non-linear parametrization of the DFSZ model in the generic case where all scalars except the lightest Higgs and the axion have masses at or beyond the TeV scale. In the second part, we study the relevance of a cold axion background (CAB) as a responsible for the dark matter in the Universe and examine its consequences through its effects on photon and cosmic ray propagation. We study the axion-photon system under the joint influence of two backgrounds: an external magnetic field and a CAB. Their effect consists in producing a three-way mixing of the axion with the two polarizations of the photon. We determine the proper frequencies and eigenvectors as well as the corresponding photon ellipticity and induced rotation of the polarization plane that depend both on the magnetic field and the local density of axions. We also comment on the possibility that some of the predicted effects could be measured in optical table-top experiments. Circularly polarized photons are energy eigenstates, with a modified dispersion relation. This enables the emission of a photon by a charged particle, which is forbidden in regular QED. We study the energy loss of a cosmic ray due and compute the energy flux of photons emitted in this way.
[ { "created": "Thu, 10 Dec 2015 16:32:47 GMT", "version": "v1" }, { "created": "Tue, 15 Dec 2015 16:01:41 GMT", "version": "v2" } ]
2015-12-16
[ [ "Renau", "Albert", "" ] ]
In the first part of the thesis, we revisit the Dine-Fischler-Srednicki-Zhitnisky axion model in light of the recent Higgs LHC results and electroweak precision data. This model is an extension of the two-Higgs-doublet model incorporating a PQ symmetry which leads to a physically acceptable axion. For generic values of the couplings, the model reproduces the minimal Standard Model, with a massless axion and all the other degrees of freedom at a very high scale. However, in some scenarios, the extra Higgses could be relatively light. We use the oblique corrections, in particular $\Delta\rho$, to constrain the mass spectrum in this case. Finally, we also work out the non-linear parametrization of the DFSZ model in the generic case where all scalars except the lightest Higgs and the axion have masses at or beyond the TeV scale. In the second part, we study the relevance of a cold axion background (CAB) as a responsible for the dark matter in the Universe and examine its consequences through its effects on photon and cosmic ray propagation. We study the axion-photon system under the joint influence of two backgrounds: an external magnetic field and a CAB. Their effect consists in producing a three-way mixing of the axion with the two polarizations of the photon. We determine the proper frequencies and eigenvectors as well as the corresponding photon ellipticity and induced rotation of the polarization plane that depend both on the magnetic field and the local density of axions. We also comment on the possibility that some of the predicted effects could be measured in optical table-top experiments. Circularly polarized photons are energy eigenstates, with a modified dispersion relation. This enables the emission of a photon by a charged particle, which is forbidden in regular QED. We study the energy loss of a cosmic ray due and compute the energy flux of photons emitted in this way.
1106.6257
Eugene Levin
Bastian Diaz Saez and Eugene Levin
Violation of the geometric scaling behaviour of the amplitude for running QCD coupling in the saturation region
13pp. and 6 figures in eps format
null
10.1016/j.nuclphysa.2011.09.003
TAUP 2930/11
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper we show that the intuitive guess that the geometric scaling behaviour should be violated in the case of the running QCD coupling, turns out to be correct. The scattering amplitude of the dipole with the size $r$ depends on new dimensional scale: $\Lambda_{QCD}$, even at large values $Y = \ln(1/x)$ and $l\,=\, \ln\Lb \as\Lb r^2\Rb/\as\Lb 1/Q^2_s\Rb\Rb$. However, in this region we found a new scaling behaviour: the amplitude is a function of $\zeta = Y\,l$. We state that only in the vicinity of the saturation scale $Q_s$ ($\as(Q^2_s)\,\ln \Lb r^2 Q^2_s\Rb\,\leq \, 1$), the amplitude shows the geometric scaling behaviour. Based on these finding the geometric scaling behavior that has been seen experimentally, stems from either we have not probed the proton at HERA and the LHC deeply inside the saturation region or that there exists the mechanism of freezing of the QCD coupling constant at $r^2 \approx 1/Q^2_s$.
[ { "created": "Thu, 30 Jun 2011 15:03:49 GMT", "version": "v1" } ]
2015-05-28
[ [ "Saez", "Bastian Diaz", "" ], [ "Levin", "Eugene", "" ] ]
In this paper we show that the intuitive guess that the geometric scaling behaviour should be violated in the case of the running QCD coupling, turns out to be correct. The scattering amplitude of the dipole with the size $r$ depends on new dimensional scale: $\Lambda_{QCD}$, even at large values $Y = \ln(1/x)$ and $l\,=\, \ln\Lb \as\Lb r^2\Rb/\as\Lb 1/Q^2_s\Rb\Rb$. However, in this region we found a new scaling behaviour: the amplitude is a function of $\zeta = Y\,l$. We state that only in the vicinity of the saturation scale $Q_s$ ($\as(Q^2_s)\,\ln \Lb r^2 Q^2_s\Rb\,\leq \, 1$), the amplitude shows the geometric scaling behaviour. Based on these finding the geometric scaling behavior that has been seen experimentally, stems from either we have not probed the proton at HERA and the LHC deeply inside the saturation region or that there exists the mechanism of freezing of the QCD coupling constant at $r^2 \approx 1/Q^2_s$.
1301.7605
Tirtha Sankar Ray
Pritibhajan Byakti, Tirtha Sankar Ray
Burgeoning the Higgs mass to 125 GeV through messenger-matter interactions in GMSB models
Contributions from kinetic mixing incorporated, typos corrected, references updated, 22 pages, 5 figures
JHEP 1305 (2013) 055
10.1007/JHEP05(2013)055
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A 125 GeV Higgs renders the simpler GMSB models unnatural, essentially pushing the soft spectrum beyond the LHC reach. A direct coupling of the matter and messenger fields, that facilitates an enhanced mixing in the squark sector, is a way to ameliorate this deficiency. We construct all possible messenger-matter interaction terms considering the messenger multiplets in 1, 5 and 10 dimensional representations of the SU(5). A Froggatt-Nielsen like flavor framework connected with the origin of fermion mass hierarchy is utilized to control the interaction terms and suppress FCNC. We perform a detailed comparative study of the efficiency of such interaction terms to boost the Higgs mass keeping the soft spectrum light. We identify the more promising models and comment on their status in present and future collider studies.
[ { "created": "Thu, 31 Jan 2013 13:07:42 GMT", "version": "v1" }, { "created": "Wed, 24 Apr 2013 19:28:09 GMT", "version": "v2" } ]
2013-05-24
[ [ "Byakti", "Pritibhajan", "" ], [ "Ray", "Tirtha Sankar", "" ] ]
A 125 GeV Higgs renders the simpler GMSB models unnatural, essentially pushing the soft spectrum beyond the LHC reach. A direct coupling of the matter and messenger fields, that facilitates an enhanced mixing in the squark sector, is a way to ameliorate this deficiency. We construct all possible messenger-matter interaction terms considering the messenger multiplets in 1, 5 and 10 dimensional representations of the SU(5). A Froggatt-Nielsen like flavor framework connected with the origin of fermion mass hierarchy is utilized to control the interaction terms and suppress FCNC. We perform a detailed comparative study of the efficiency of such interaction terms to boost the Higgs mass keeping the soft spectrum light. We identify the more promising models and comment on their status in present and future collider studies.
1610.08358
Ulas Ozdem
A. Kucukarslan, U. Ozdem, A. Ozpineci
Tensor form factors of the octet hyperons in QCD
15 pages, 6 figures
Phys. Rev. D 94, 094010 (2016)
10.1103/PhysRevD.94.094010
null
hep-ph
http://creativecommons.org/publicdomain/zero/1.0/
Light-cone QCD sum rules to leading order in QCD are used to investigate the tensor form factors of the $\Sigma-\Sigma$, $\Xi-\Xi$ and $ \Sigma-\Lambda$ transitions in the range $1 GeV^2 \leq Q^2 \leq 10 GeV^2$. The DAs of $\Sigma$, $\Xi$ and $\Lambda$ baryon have been calculated without higher order terms. Then, study including higher order corrections have been done for $\Sigma$ and $\Lambda$ baryon. The result of form factors are obtained using these two DAs. We make a comparison with the predictions of the chiral quark soliton model.
[ { "created": "Wed, 26 Oct 2016 14:43:41 GMT", "version": "v1" }, { "created": "Sat, 12 Nov 2016 15:16:17 GMT", "version": "v2" } ]
2016-11-15
[ [ "Kucukarslan", "A.", "" ], [ "Ozdem", "U.", "" ], [ "Ozpineci", "A.", "" ] ]
Light-cone QCD sum rules to leading order in QCD are used to investigate the tensor form factors of the $\Sigma-\Sigma$, $\Xi-\Xi$ and $ \Sigma-\Lambda$ transitions in the range $1 GeV^2 \leq Q^2 \leq 10 GeV^2$. The DAs of $\Sigma$, $\Xi$ and $\Lambda$ baryon have been calculated without higher order terms. Then, study including higher order corrections have been done for $\Sigma$ and $\Lambda$ baryon. The result of form factors are obtained using these two DAs. We make a comparison with the predictions of the chiral quark soliton model.
hep-ph/9503310
Matveev Victor I.
V. I. Matveev, S. G. Tolmanov
THE ENERGY LOSSES OF RELATIVISTIC HIGHCHARGED IONS IN THE COLLISIONS WITH ATOMS
9 pages, latex
null
null
EFI-95-03
hep-ph
null
The energy losses at collisions of heavy multiplycharged ions with light atoms have been considered under circumstances the ion charge Z>>1 and the relative colliding velocity v>>1, so that Z~v=<c, where c - the light velocity (atomic units are used). In this region of parameters the Born approximation are not justificative. The simple formulas for effective stopping are obtained, the comparison with effective stopping calculated in the Born approximation are carried out.
[ { "created": "Thu, 9 Mar 1995 08:25:45 GMT", "version": "v1" } ]
2007-05-23
[ [ "Matveev", "V. I.", "" ], [ "Tolmanov", "S. G.", "" ] ]
The energy losses at collisions of heavy multiplycharged ions with light atoms have been considered under circumstances the ion charge Z>>1 and the relative colliding velocity v>>1, so that Z~v=<c, where c - the light velocity (atomic units are used). In this region of parameters the Born approximation are not justificative. The simple formulas for effective stopping are obtained, the comparison with effective stopping calculated in the Born approximation are carried out.
hep-ph/0103283
Jean-Marc Richard
Andre Martin (CERN) and Jean-Marc Richard (Grenoble)
Investigation of the Role of Elastic Unitarity in High-Energy Scattering: Gribov's Theorem and the Froissart Bound
11 pages, 1 figures, latex with sproc.sty
null
null
CERN-TH/2001-086, ISN-01-026
hep-ph
null
We re-examine V. Gribov's theorem of 1960 according to which the total cross-section cannot approach a finite non-zero limit with, at the same time, a diffraction peak having a finite slope. We are very close to proving by an explicit counter-example that elastic unitarity in the elastic region is an essential ingredient of the proof. By analogy, we raise the question of the saturation of the Froissart-Martin bound, for which no examples incorporating elastic unitarity exist at the present time.
[ { "created": "Tue, 27 Mar 2001 13:09:49 GMT", "version": "v1" } ]
2007-05-23
[ [ "Martin", "Andre", "", "CERN" ], [ "Richard", "Jean-Marc", "", "Grenoble" ] ]
We re-examine V. Gribov's theorem of 1960 according to which the total cross-section cannot approach a finite non-zero limit with, at the same time, a diffraction peak having a finite slope. We are very close to proving by an explicit counter-example that elastic unitarity in the elastic region is an essential ingredient of the proof. By analogy, we raise the question of the saturation of the Froissart-Martin bound, for which no examples incorporating elastic unitarity exist at the present time.
1209.6071
Michael P\'erez
M Jay Perez, Pierre Ramond, and Jue Zhang
On Mixing Supersymmetry and Family Symmetry Breakings
38 Pages, 11 Figures. Updated file to include minor changes, update figures, and to correct errors in Eq. 4.15. An error was found in the first version soft masses (Eq.4.15), however the conclusions of the paper are unaffected. We have included the Journal reference and DOI
Phys. Rev. D 87, 035021 (2013) [22 pages]
10.1103/PhysRevD.87.035021
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a toy model in which the Higgs sector fields transform as non-Abelian representations of a family symmetry group, and consider the possibility that the extra family partners of the Higgs particles act as messengers for both supersymmetry and family symmetry breakings. Although such mediation schemes generically produce family dependent soft supersymmetry breaking terms at the messenger scale, we demonstrate the existence of a focusing mechanism which may erase such hierarchies through renormalization group running.
[ { "created": "Wed, 26 Sep 2012 20:36:46 GMT", "version": "v1" }, { "created": "Mon, 11 Mar 2013 18:13:01 GMT", "version": "v2" } ]
2013-03-12
[ [ "Perez", "M Jay", "" ], [ "Ramond", "Pierre", "" ], [ "Zhang", "Jue", "" ] ]
We present a toy model in which the Higgs sector fields transform as non-Abelian representations of a family symmetry group, and consider the possibility that the extra family partners of the Higgs particles act as messengers for both supersymmetry and family symmetry breakings. Although such mediation schemes generically produce family dependent soft supersymmetry breaking terms at the messenger scale, we demonstrate the existence of a focusing mechanism which may erase such hierarchies through renormalization group running.
2209.09474
Thomas A. Trainor
Thomas A. Trainor
How the Blast-Wave Model Describes PID Hadron Spectra from 5 TeV p-Pb Collisions
6 pages, 7 figures
null
null
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
The blast-wave (BW) spectrum model has been applied extensively to nucleus-nucleus collision data with the intention to demonstrate formation of a quark-gluon plasma (QGP) in more-central A-A collisions. More recently the BW model has been applied to p-p, d-Au and p-Pb collisions. Such results are interpreted to indicate that ``collectivity'' (flows) and QGP appear in smaller systems. I consider variations of the BW model and supporting assumptions. In this talk I review BW analysis of identified-hadron spectra from 5 TeV p-Pb collisions and examine the shape evolution of model spectra with collision centrality. I evaluate data-model fit quality using conventional statistical measures. I conclude that the BW model is not a valid data model.
[ { "created": "Tue, 20 Sep 2022 05:15:39 GMT", "version": "v1" }, { "created": "Tue, 31 Jan 2023 06:55:01 GMT", "version": "v2" } ]
2023-02-01
[ [ "Trainor", "Thomas A.", "" ] ]
The blast-wave (BW) spectrum model has been applied extensively to nucleus-nucleus collision data with the intention to demonstrate formation of a quark-gluon plasma (QGP) in more-central A-A collisions. More recently the BW model has been applied to p-p, d-Au and p-Pb collisions. Such results are interpreted to indicate that ``collectivity'' (flows) and QGP appear in smaller systems. I consider variations of the BW model and supporting assumptions. In this talk I review BW analysis of identified-hadron spectra from 5 TeV p-Pb collisions and examine the shape evolution of model spectra with collision centrality. I evaluate data-model fit quality using conventional statistical measures. I conclude that the BW model is not a valid data model.
1308.2783
Li-gong Bian
Ligong Bian
RGE, the naturalness problem and the understanding of the Higgs mass term
16pages, 9figures, accepted for publication as a Regular Article in Physical Review D
null
10.1103/PhysRevD.88.056022
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The naturalness problem might be studied on the complex two dimensional plane with the technique of dimensional regularization(DREG). The Renormalization group equation(RGE) of the Higgs mass on the plane suggests the Higgs mass approaches zero at ultraviolate (UV) scale, the scale can be Planck scale when the top quark pole mass $M_{t}=168$ GeV. The real issue of the naturalness problem in the sense of Wilsonian renormalization group method is not about quadratic divergences but the rescaling effect. The Higgs mass can be considered to be one composed mass. All terms in the lagrangian in this scenario are marginal terms and no relevant terms are left, thus no rescaling effect to cause the naturalness problem anymore. RGE of the vacuum expectation value (VEV) in the Landau gauge up to two-loop order is studied. Scale-dependent behavior of the composed Higgs mass shows that we can have one tiny Higgs mass at high energy scale, even around the Planck scale, when $M_{t}\leq170.7$ GeV.
[ { "created": "Tue, 13 Aug 2013 08:27:17 GMT", "version": "v1" }, { "created": "Thu, 19 Sep 2013 01:51:36 GMT", "version": "v2" } ]
2015-06-16
[ [ "Bian", "Ligong", "" ] ]
The naturalness problem might be studied on the complex two dimensional plane with the technique of dimensional regularization(DREG). The Renormalization group equation(RGE) of the Higgs mass on the plane suggests the Higgs mass approaches zero at ultraviolate (UV) scale, the scale can be Planck scale when the top quark pole mass $M_{t}=168$ GeV. The real issue of the naturalness problem in the sense of Wilsonian renormalization group method is not about quadratic divergences but the rescaling effect. The Higgs mass can be considered to be one composed mass. All terms in the lagrangian in this scenario are marginal terms and no relevant terms are left, thus no rescaling effect to cause the naturalness problem anymore. RGE of the vacuum expectation value (VEV) in the Landau gauge up to two-loop order is studied. Scale-dependent behavior of the composed Higgs mass shows that we can have one tiny Higgs mass at high energy scale, even around the Planck scale, when $M_{t}\leq170.7$ GeV.
2402.16953
Sabya Sachi Chatterjee
Sabya Sachi Chatterjee, St\'ephane Lavignac, O. G. Miranda, and G. Sanchez Garcia
Exploring the sensitivity to non-standard and generalized neutrino interactions through coherent elastic neutrino-nucleus scattering with a NaI detector
31 pages, 10 pdf figures, and 4 tables
null
null
null
hep-ph hep-ex nucl-th
http://creativecommons.org/publicdomain/zero/1.0/
After the first observation of coherent elastic neutrino-nucleus scattering (CE$\nu$NS) by the COHERENT collaboration, many efforts are being made to improve the measurement of this process, making it possible to constrain new physics in the neutrino sector. In this paper, we study the sensitivity to non-standard interactions (NSIs) and generalized neutrino interactions (GNIs) of a NaI detector with characteristics similar to the one that is currently being deployed at the Spallation Neutron Source at Oak Ridge National Laboratory. We show that such a detector, whose target nuclei have significantly different proton to neutron ratios (at variance with the current CsI detector), could help to partially break the parameter degeneracies arising from the interference between the Standard Model and NSI contributions to the CE$\nu$NS cross section, as well as between different NSI parameters. By contrast, only a slight improvement over the current CsI constraints is expected for parameters that do not interfere with the SM contribution. We find that a significant reduction of the background level would make the NaI detector considered in this paper very efficient at breaking degeneracies among NSI parameters.
[ { "created": "Mon, 26 Feb 2024 19:00:06 GMT", "version": "v1" } ]
2024-02-28
[ [ "Chatterjee", "Sabya Sachi", "" ], [ "Lavignac", "Stéphane", "" ], [ "Miranda", "O. G.", "" ], [ "Garcia", "G. Sanchez", "" ] ]
After the first observation of coherent elastic neutrino-nucleus scattering (CE$\nu$NS) by the COHERENT collaboration, many efforts are being made to improve the measurement of this process, making it possible to constrain new physics in the neutrino sector. In this paper, we study the sensitivity to non-standard interactions (NSIs) and generalized neutrino interactions (GNIs) of a NaI detector with characteristics similar to the one that is currently being deployed at the Spallation Neutron Source at Oak Ridge National Laboratory. We show that such a detector, whose target nuclei have significantly different proton to neutron ratios (at variance with the current CsI detector), could help to partially break the parameter degeneracies arising from the interference between the Standard Model and NSI contributions to the CE$\nu$NS cross section, as well as between different NSI parameters. By contrast, only a slight improvement over the current CsI constraints is expected for parameters that do not interfere with the SM contribution. We find that a significant reduction of the background level would make the NaI detector considered in this paper very efficient at breaking degeneracies among NSI parameters.
2006.16776
Zhi-Gang Wang
Zhi-Gang Wang, Hui-Juan Wang
Analysis of the 1S and 2S states of the $\Lambda_Q$ and $\Xi_Q$ with the QCD sum rules
15 pages, 17 figures
Chin. Phys. C45 (2021) 013109
10.1088/1674-1137/abc1d3
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this article, we study the ground states and the first radial excited states of the flavor antitriplet heavy baryon states $\Lambda_Q$ and $\Xi_Q$ with the spin-parity $J^P={1\over 2}^{+}$ by carrying out the operator product expansion up to the vacuum condensates of dimension $10$ in a consistent way. We observe that the higher dimensional vacuum condensates play an important role, and obtain very stable QCD sum rules with variations of the Borel parameters for the heavy baryon states for the first time. The predicted masses $6.08\pm0.09\,\rm{GeV}$, $2.78\pm0.08\,\rm{GeV}$ and $2.96\pm0.09\,\rm{GeV}$ for the first radial excited states $\Lambda_b(\rm 2S)$, $\Lambda_c(\rm 2S)$ and $\Xi_c(\rm 2S)$ respectively are in excellent agreement with the experimental data and support assigning the $\Lambda_b(6072)$, $\Lambda_c(2765)$ and $\Xi_c(2980/2970)$ to be the first radial excited states of the $\Lambda_b$, $\Lambda_c$ and $\Xi_c$, respectively, the predicted mass $6.24\pm0.07\,\rm{GeV}$ for the $\Xi_b(\rm 2S)$ can be confronted to the experimental data in the future.
[ { "created": "Tue, 30 Jun 2020 13:31:49 GMT", "version": "v1" }, { "created": "Mon, 10 Aug 2020 08:25:07 GMT", "version": "v2" }, { "created": "Fri, 28 Aug 2020 08:04:46 GMT", "version": "v3" } ]
2020-12-29
[ [ "Wang", "Zhi-Gang", "" ], [ "Wang", "Hui-Juan", "" ] ]
In this article, we study the ground states and the first radial excited states of the flavor antitriplet heavy baryon states $\Lambda_Q$ and $\Xi_Q$ with the spin-parity $J^P={1\over 2}^{+}$ by carrying out the operator product expansion up to the vacuum condensates of dimension $10$ in a consistent way. We observe that the higher dimensional vacuum condensates play an important role, and obtain very stable QCD sum rules with variations of the Borel parameters for the heavy baryon states for the first time. The predicted masses $6.08\pm0.09\,\rm{GeV}$, $2.78\pm0.08\,\rm{GeV}$ and $2.96\pm0.09\,\rm{GeV}$ for the first radial excited states $\Lambda_b(\rm 2S)$, $\Lambda_c(\rm 2S)$ and $\Xi_c(\rm 2S)$ respectively are in excellent agreement with the experimental data and support assigning the $\Lambda_b(6072)$, $\Lambda_c(2765)$ and $\Xi_c(2980/2970)$ to be the first radial excited states of the $\Lambda_b$, $\Lambda_c$ and $\Xi_c$, respectively, the predicted mass $6.24\pm0.07\,\rm{GeV}$ for the $\Xi_b(\rm 2S)$ can be confronted to the experimental data in the future.
hep-ph/0611219
Hylke Koers
Hylke B. J. Koers, Asaf Pe'er, and Ralph A. M. J. Wijers
Parameterization of the energy and rapidity distributions of secondary pions and kaons produced in energetic proton-proton collisions
17 pages, 15 figures, revtex4. Submitted to Phys.Rev.D
null
null
NIKHEF-2006-010
hep-ph astro-ph
null
The possibility of proton acceleration to very high energies in astrophysical sources may have unique observational consequences. In particular, the decay of secondary mesons created in the interaction of energetic protons with photons or nucleons gives rise to high-energy gamma rays and neutrinos with potentially observable fluxes. Recently, there has been considerable interest in the parameterization of the energy spectra of these secondaries. Less attention has been paid to the angular distributions, which may have an important effect on observational quantities and are required to address collisions between protons with different energies and an arbitrary scattering angle. In this work, we study the complete particle distributions of secondary mesons created in proton-proton collisions. We present parameterizations of the energy and rapidity distributions of secondary pions and kaons that reproduce results generated with the event generator PYTHIA to within ~10% in the bulk of the parameter space. The parameterizations are based on incident proton energies from 1 TeV to 1 PeV and are suited for extrapolation to higher energies. We present several applications of these parameterizations. Energy spectra and angular distributions of stable decay products (electrons, neutrinos and gamma rays) follow readily. We give an example of the gamma-ray spectrum that results from the decay of pi0 mesons created in a proton-proton collision. We show that there is a strong correlation between the energy of secondary mesons and the degree of collimation around the direction of the colliding protons. This effect may have important implications for the detection possibility of neutrinos created in the interaction of a developing GRB with its surroundings.
[ { "created": "Thu, 16 Nov 2006 15:57:55 GMT", "version": "v1" } ]
2007-05-23
[ [ "Koers", "Hylke B. J.", "" ], [ "Pe'er", "Asaf", "" ], [ "Wijers", "Ralph A. M. J.", "" ] ]
The possibility of proton acceleration to very high energies in astrophysical sources may have unique observational consequences. In particular, the decay of secondary mesons created in the interaction of energetic protons with photons or nucleons gives rise to high-energy gamma rays and neutrinos with potentially observable fluxes. Recently, there has been considerable interest in the parameterization of the energy spectra of these secondaries. Less attention has been paid to the angular distributions, which may have an important effect on observational quantities and are required to address collisions between protons with different energies and an arbitrary scattering angle. In this work, we study the complete particle distributions of secondary mesons created in proton-proton collisions. We present parameterizations of the energy and rapidity distributions of secondary pions and kaons that reproduce results generated with the event generator PYTHIA to within ~10% in the bulk of the parameter space. The parameterizations are based on incident proton energies from 1 TeV to 1 PeV and are suited for extrapolation to higher energies. We present several applications of these parameterizations. Energy spectra and angular distributions of stable decay products (electrons, neutrinos and gamma rays) follow readily. We give an example of the gamma-ray spectrum that results from the decay of pi0 mesons created in a proton-proton collision. We show that there is a strong correlation between the energy of secondary mesons and the degree of collimation around the direction of the colliding protons. This effect may have important implications for the detection possibility of neutrinos created in the interaction of a developing GRB with its surroundings.
hep-ph/0510012
Alexei Nefediev
L.Ya.Glozman (Univ. Graz), A.V.Nefediev (ITEP, Moscow), J.E.F.T.Ribeiro (IST, Lisbon)
Chiral symmetry restoration in excited hadrons, quantum fluctuations, and quasiclassics
RevTeX4, 20 pages, 4 Postscript figures, uses epsfig.sty, typos corrected
Phys.Rev. D72 (2005) 094002
10.1103/PhysRevD.72.094002
null
hep-ph hep-ex hep-lat hep-th nucl-th
null
In this paper, we discuss the transition to the semiclassical regime in excited hadrons, and consequently, the restoration of chiral symmetry for these states. We use a generalised Nambu-Jona-Lasinio model with the interaction between quarks in the form of the instantaneous Lorentz-vector confining potential. This model is known to provide spontaneous breaking of chiral symmetry in the vacuum via the standard selfenergy loops for valence quarks. It has been shown recently that the effective single-quark potential is of the Lorentz-scalar nature, for the low-lying hadrons, while, for the high-lying states, it becomes a pure Lorentz vector and hence the model exhibits the restoration of chiral symmetry. We demonstrate explicitly the quantum nature of chiral symmetry breaking, the absence of chiral symmetry breaking in the classical limit as well as the transition to the semiclassical regime for excited states, where the effect of chiral symmetry breaking becomes only a small correction to the classical contributions.
[ { "created": "Sun, 2 Oct 2005 20:19:17 GMT", "version": "v1" }, { "created": "Tue, 18 Oct 2005 12:32:04 GMT", "version": "v2" }, { "created": "Thu, 3 Nov 2005 11:11:18 GMT", "version": "v3" } ]
2009-11-11
[ [ "Glozman", "L. Ya.", "", "Univ. Graz" ], [ "Nefediev", "A. V.", "", "ITEP, Moscow" ], [ "Ribeiro", "J. E. F. T.", "", "IST, Lisbon" ] ]
In this paper, we discuss the transition to the semiclassical regime in excited hadrons, and consequently, the restoration of chiral symmetry for these states. We use a generalised Nambu-Jona-Lasinio model with the interaction between quarks in the form of the instantaneous Lorentz-vector confining potential. This model is known to provide spontaneous breaking of chiral symmetry in the vacuum via the standard selfenergy loops for valence quarks. It has been shown recently that the effective single-quark potential is of the Lorentz-scalar nature, for the low-lying hadrons, while, for the high-lying states, it becomes a pure Lorentz vector and hence the model exhibits the restoration of chiral symmetry. We demonstrate explicitly the quantum nature of chiral symmetry breaking, the absence of chiral symmetry breaking in the classical limit as well as the transition to the semiclassical regime for excited states, where the effect of chiral symmetry breaking becomes only a small correction to the classical contributions.
1109.1132
Mauro Anselmino
Mauro Anselmino, Vincenzo Barone and Aram Kotzinian
Double hadron lepto-production in the current and target fragmentation regions
14 pages, 2 figures
null
10.1016/j.physletb.2011.10.064
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the inclusive production of two hadrons in deep inelastic processes, l N ---> l h_1 h_2 X, with h_1 in the current fragmentation region (CFR) and h_2 in the target fragmentation region (TFR). Assuming a factorized scheme, the recently introduced polarized and transverse momentum dependent fracture functions couple to the transverse momentum dependent fragmentation functions. This allows the full exploration of the fracture functions for transversely polarized quarks. Some particular cases are considered.
[ { "created": "Tue, 6 Sep 2011 10:10:40 GMT", "version": "v1" } ]
2015-05-30
[ [ "Anselmino", "Mauro", "" ], [ "Barone", "Vincenzo", "" ], [ "Kotzinian", "Aram", "" ] ]
We study the inclusive production of two hadrons in deep inelastic processes, l N ---> l h_1 h_2 X, with h_1 in the current fragmentation region (CFR) and h_2 in the target fragmentation region (TFR). Assuming a factorized scheme, the recently introduced polarized and transverse momentum dependent fracture functions couple to the transverse momentum dependent fragmentation functions. This allows the full exploration of the fracture functions for transversely polarized quarks. Some particular cases are considered.
hep-ph/9609271
Lu Gong Ru
Gongru Lu, Chongxing Yue, Yigang Cao, Zhaohua Xiong and Zhenjun Xiao
Study on the rare radiative decay $B_c \to D_s^*\gamma$ in the standard model and multiscale walking technicolor model
16 pages, Latex, no macros, 1 figure(in Latex), hard copy is available upon request. to appear in Phys. Rev. D
Phys.Rev.D54:5647-5652,1996
10.1103/PhysRevD.54.5647
HNU-TH-96/8
hep-ph
null
Applying the perturbative QCD ( PQCD ) method, we study the decay $B_c\rightarrow D_s^*\gamma$ in the standard model and multiscale walking technicolor model. In the SM, we find that the contribution of weak annihilation is more important than that of the electromagnetic penguin. The presence of Pseudo-Goldstone-Bosons in the MWTCM leads to a large enhancement in the rate of $B_c\rightarrow D_s^*\gamma$, but this model is in conflict with the branching ratio of $Z\rightarrow b\overline b$ ( $R_b$ ) and the CLEO data on the branching ratio BR ( $b\rightarrow s\gamma$ ). If topcolor is further introduced, the calculated results in the topcolor assisted MWTCM can be suppressed and be in agreement with the CLEO data for a certain range of the parameters.
[ { "created": "Fri, 6 Sep 1996 16:06:18 GMT", "version": "v1" } ]
2008-12-25
[ [ "Lu", "Gongru", "" ], [ "Yue", "Chongxing", "" ], [ "Cao", "Yigang", "" ], [ "Xiong", "Zhaohua", "" ], [ "Xiao", "Zhenjun", "" ] ]
Applying the perturbative QCD ( PQCD ) method, we study the decay $B_c\rightarrow D_s^*\gamma$ in the standard model and multiscale walking technicolor model. In the SM, we find that the contribution of weak annihilation is more important than that of the electromagnetic penguin. The presence of Pseudo-Goldstone-Bosons in the MWTCM leads to a large enhancement in the rate of $B_c\rightarrow D_s^*\gamma$, but this model is in conflict with the branching ratio of $Z\rightarrow b\overline b$ ( $R_b$ ) and the CLEO data on the branching ratio BR ( $b\rightarrow s\gamma$ ). If topcolor is further introduced, the calculated results in the topcolor assisted MWTCM can be suppressed and be in agreement with the CLEO data for a certain range of the parameters.
hep-ph/0104132
Johann Rafelski
Johann Rafelski (Tucson), Giorgio Torrieri (Tucson) and Jean Letessier(Paris)
Strangeness and QGP freeze-out dynamics
Presented at XXVI Rencotres de Moriond, March 17-24, 2001 Les Arcs, Freance
null
null
null
hep-ph
null
We compare chemical and thermal analysis of the SPS Pb--Pb results at $158A$ GeV, and present a first chemical analysis of RHIC results. We show how a combined analysis of several strange hadron resonances can be used in a study of freeze-out dynamics.
[ { "created": "Fri, 13 Apr 2001 00:46:04 GMT", "version": "v1" } ]
2007-05-23
[ [ "Rafelski", "Johann", "", "Tucson" ], [ "Torrieri", "Giorgio", "", "Tucson" ], [ "Letessier", "Jean", "", "Paris" ] ]
We compare chemical and thermal analysis of the SPS Pb--Pb results at $158A$ GeV, and present a first chemical analysis of RHIC results. We show how a combined analysis of several strange hadron resonances can be used in a study of freeze-out dynamics.
hep-ph/0212238
Brian C. Tiburzi
B. C. Tiburzi, G. A. Miller
Generalized parton distributions and double distributions for q q-bar pions
10 pages, 7 figures, RevTex4, reference added, typos corrected
Phys.Rev. D67 (2003) 113004
10.1103/PhysRevD.67.113004
NT-UW 02-37
hep-ph nucl-th
null
We consider two simple covariant models for pions (one with scalar and the other with spin-1/2 constituents). Pion generalized parton distributions are derived by integration over the light-cone energy. The model distributions are consistent with all known properties of generalized parton distributions, including positivity. We also construct the corresponding double distributions by appealing to Lorentz invariance. These ostensibly constructed double distributions lead to different generalized parton distributions that need not respect the positivity constraints. This inconsistency arises from the ambiguity inherent in defining double distributions in a one-component formalism (even in the absence of the Polyakov-Weiss term). We demonstrate that the correct model double distributions can be calculated from non-diagonal matrix elements of twist-two operators.
[ { "created": "Mon, 16 Dec 2002 23:53:48 GMT", "version": "v1" }, { "created": "Wed, 18 Dec 2002 23:23:23 GMT", "version": "v2" } ]
2009-11-07
[ [ "Tiburzi", "B. C.", "" ], [ "Miller", "G. A.", "" ] ]
We consider two simple covariant models for pions (one with scalar and the other with spin-1/2 constituents). Pion generalized parton distributions are derived by integration over the light-cone energy. The model distributions are consistent with all known properties of generalized parton distributions, including positivity. We also construct the corresponding double distributions by appealing to Lorentz invariance. These ostensibly constructed double distributions lead to different generalized parton distributions that need not respect the positivity constraints. This inconsistency arises from the ambiguity inherent in defining double distributions in a one-component formalism (even in the absence of the Polyakov-Weiss term). We demonstrate that the correct model double distributions can be calculated from non-diagonal matrix elements of twist-two operators.
hep-ph/9501227
Ellwanger
Ulrich ELLWANGER
HOW TO LIMIT RADIATIVE CORRECTIONS TO THE COSMOLOGICAL CONSTANT BY M^4_Susy
14 pages, plain Tex, no figures
Phys.Lett. B349 (1995) 57-62
10.1016/0370-2693(95)00218-A
LPTHE Orsay 94-106
hep-ph
null
Supergravity models are constructed in which the effective low energy theory contains only ``super-soft'' explicit supersymmetry breaking: masses of the scalars and pseudoscalars within a multiplet are split in opposite directions. With this form of supersymmetry breaking the radiative corrections of the matter sector to the vacuum energy are bounded by ${\cal O} (M^4_{Susy})$ to all orders in perturbation theory, and we require $Str M^2 = 0$ including the hidden sector. The models are based on K\"ahler potentials obtained in recent orbifold compactifications, and we describe the construction of realistic theories.
[ { "created": "Fri, 6 Jan 1995 13:00:20 GMT", "version": "v1" } ]
2016-09-01
[ [ "ELLWANGER", "Ulrich", "" ] ]
Supergravity models are constructed in which the effective low energy theory contains only ``super-soft'' explicit supersymmetry breaking: masses of the scalars and pseudoscalars within a multiplet are split in opposite directions. With this form of supersymmetry breaking the radiative corrections of the matter sector to the vacuum energy are bounded by ${\cal O} (M^4_{Susy})$ to all orders in perturbation theory, and we require $Str M^2 = 0$ including the hidden sector. The models are based on K\"ahler potentials obtained in recent orbifold compactifications, and we describe the construction of realistic theories.
1903.01474
Josu Hernandez-Garcia
Josu Hernandez-Garcia and Stephen F. King
New Weinberg operator for neutrino mass and its seesaw origin
19 pages, 6 figures. v2: minor typos corrected and references added
null
10.1007/JHEP05(2019)169
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider a new Weinberg operator for neutrino mass of the form $H_u\tilde{H_d}L_iL_j$ involving two different Higgs doublets $H_u, H_d$ with opposite hypercharge, where $\tilde{H_d}$ is the charge conjugated doublet. It may arise from a model where the two Higgs doublets carry the same charge under a $U(1)'$ gauge group which forbids the usual Weinberg operator but allows the mixed one. The new Weinberg operator may be generated via two right-handed neutrinos oppositely charged under the $U(1)'$, which may be identified as components of a fourth vector-like family in a complete model. Such a version of the type I seesaw model, which we refer to as type Ib to distinguish it from the usual type Ia seesaw mechanism which yields the usual Weinberg operator, allows the possibility of having potentially large violations of unitarity of the leptonic mixing matrix whose bounds we explore. We also consider the relaxation of the unitarity bounds due to the further addition of a single right-handed neutrino, neutral under $U(1)'$, yielding a usual type Ia seesaw contribution.
[ { "created": "Mon, 4 Mar 2019 19:00:02 GMT", "version": "v1" }, { "created": "Tue, 12 Mar 2019 18:00:38 GMT", "version": "v2" } ]
2019-06-26
[ [ "Hernandez-Garcia", "Josu", "" ], [ "King", "Stephen F.", "" ] ]
We consider a new Weinberg operator for neutrino mass of the form $H_u\tilde{H_d}L_iL_j$ involving two different Higgs doublets $H_u, H_d$ with opposite hypercharge, where $\tilde{H_d}$ is the charge conjugated doublet. It may arise from a model where the two Higgs doublets carry the same charge under a $U(1)'$ gauge group which forbids the usual Weinberg operator but allows the mixed one. The new Weinberg operator may be generated via two right-handed neutrinos oppositely charged under the $U(1)'$, which may be identified as components of a fourth vector-like family in a complete model. Such a version of the type I seesaw model, which we refer to as type Ib to distinguish it from the usual type Ia seesaw mechanism which yields the usual Weinberg operator, allows the possibility of having potentially large violations of unitarity of the leptonic mixing matrix whose bounds we explore. We also consider the relaxation of the unitarity bounds due to the further addition of a single right-handed neutrino, neutral under $U(1)'$, yielding a usual type Ia seesaw contribution.
hep-ph/0512115
Indranath Bhattacharyya
Indranath Bhattacharyya
Neutrino Bremsstrahlung Process in highly degenerate magnetized electron gas
12 pages including 2 figures and 1 table
J.Phys.G32:925-934,2006
10.1088/0954-3899/32/7/003
null
hep-ph
null
In this article the neutrino bremsstrahlung process is considered in presence of strong magnetic field, though the calculations for this process in absence of magnetic field are also carried out simultaneously. The electrons involved in this process are supposed to be highly degenerate and relativistic. The scattering cross sections and energy loss rates for both cases, in presence and absence of magnetic field, are calculated in the extreme-relativistic limit. Two results are compared in the range of temperature $5.9\times 10^{9}$ K $< T\leq 10^{11}$ K and magnetic field $10^{14} - 10^{16}$ G at a fixed density $\sim 10^{15}$ $gm/cc$, a typical environment during the cooling of magnetized neutron star. The interpretation of our result is briefly discussed and the importance of this process during the stellar evolution is speculated.
[ { "created": "Fri, 9 Dec 2005 08:55:37 GMT", "version": "v1" }, { "created": "Tue, 14 Mar 2006 18:52:48 GMT", "version": "v2" }, { "created": "Thu, 16 Mar 2006 04:18:39 GMT", "version": "v3" }, { "created": "Thu, 4 May 2006 13:34:36 GMT", "version": "v4" }, { "cre...
2008-11-26
[ [ "Bhattacharyya", "Indranath", "" ] ]
In this article the neutrino bremsstrahlung process is considered in presence of strong magnetic field, though the calculations for this process in absence of magnetic field are also carried out simultaneously. The electrons involved in this process are supposed to be highly degenerate and relativistic. The scattering cross sections and energy loss rates for both cases, in presence and absence of magnetic field, are calculated in the extreme-relativistic limit. Two results are compared in the range of temperature $5.9\times 10^{9}$ K $< T\leq 10^{11}$ K and magnetic field $10^{14} - 10^{16}$ G at a fixed density $\sim 10^{15}$ $gm/cc$, a typical environment during the cooling of magnetized neutron star. The interpretation of our result is briefly discussed and the importance of this process during the stellar evolution is speculated.
hep-ph/0310283
Bachir Moussallam
P. B\"uttiker, S. Descotes-Genon, B. Moussallam
A new analysis of $\pi K$ scattering from Roy and Steiner type equations
45 pages, 17 figures. v2: New title, minor corrections
Eur.Phys.J.C33:409-432,2004
10.1140/epjc/s2004-01591-1
HISKP-TH-03/18, IPNO/DR-03-08, LPT-ORSAY/03-76
hep-ph
null
With the aim of generating new constraints on the OZI suppressed couplings of chiral perturbation theory a set of six equations of the Roy and Steiner type for the $S$- and $P$-waves of the $\pi K$ scattering amplitudes is derived. The range of validity and the multiplicity of the solutions are discussed. Precise numerical solutions are obtained in the range $E\lapprox 1$ GeV which make use as input, for the first time, of the most accurate experimental data available at $E > 1$ GeV for both $\pi K\to\pi K$ and $\pi\pi\to K\bar{K}$ amplitudes. Our main result is the determination of a narrow allowed region for the two S-wave scattering lengths. Present experimental data below 1 GeV are found to be in generally poor agreement with our results. A set of threshold expansion parameters, as well as sub-threshold parameters are computed. For the latter, matching with the SU(3) chiral expansion at NLO is performed.
[ { "created": "Fri, 24 Oct 2003 09:54:51 GMT", "version": "v1" }, { "created": "Mon, 27 Oct 2003 15:46:30 GMT", "version": "v2" }, { "created": "Mon, 5 Jan 2004 13:45:04 GMT", "version": "v3" } ]
2008-11-26
[ [ "Büttiker", "P.", "" ], [ "Descotes-Genon", "S.", "" ], [ "Moussallam", "B.", "" ] ]
With the aim of generating new constraints on the OZI suppressed couplings of chiral perturbation theory a set of six equations of the Roy and Steiner type for the $S$- and $P$-waves of the $\pi K$ scattering amplitudes is derived. The range of validity and the multiplicity of the solutions are discussed. Precise numerical solutions are obtained in the range $E\lapprox 1$ GeV which make use as input, for the first time, of the most accurate experimental data available at $E > 1$ GeV for both $\pi K\to\pi K$ and $\pi\pi\to K\bar{K}$ amplitudes. Our main result is the determination of a narrow allowed region for the two S-wave scattering lengths. Present experimental data below 1 GeV are found to be in generally poor agreement with our results. A set of threshold expansion parameters, as well as sub-threshold parameters are computed. For the latter, matching with the SU(3) chiral expansion at NLO is performed.
2011.09244
Xu Cao
Xu Cao, Jian-Ping Dai, Zhi Yang
Photoproduction of strange hidden-charm and hidden-bottom states
20 pages, 7 figures
Eur. Phys. J. C (2021) 81:184
10.1140/epjc/s10052-021-08858-7
null
hep-ph
http://creativecommons.org/licenses/by-nc-sa/4.0/
Recently BESIII collaboration discovered a charged strange hidden-charm state $Z_{cs}$(3985) in the $D_s^-D^{*0} + D_s^{*-}D^{0}$ spectrum. A higher $Z'_{cs}$ state coupling to $\bar{D}_s^{*-}D^{*0}$ is expected by SU(3)-flavor symmetry, and their bottom partners are anticipated by heavy quark flavor symmetry. Here we study the photoproduction of these exotic states and investigate carefully the background from Pomeron exchange. Our results indicate that the maximal photoproduction cross section of strange partner is around 1 $\sim$ 2 orders of magnitude smaller than that of the corresponding non-strange states. The possibility of searching for them in future electron-ion colliders (EIC) is briefly discussed.
[ { "created": "Wed, 18 Nov 2020 12:32:56 GMT", "version": "v1" }, { "created": "Thu, 25 Feb 2021 03:54:35 GMT", "version": "v2" } ]
2021-02-26
[ [ "Cao", "Xu", "" ], [ "Dai", "Jian-Ping", "" ], [ "Yang", "Zhi", "" ] ]
Recently BESIII collaboration discovered a charged strange hidden-charm state $Z_{cs}$(3985) in the $D_s^-D^{*0} + D_s^{*-}D^{0}$ spectrum. A higher $Z'_{cs}$ state coupling to $\bar{D}_s^{*-}D^{*0}$ is expected by SU(3)-flavor symmetry, and their bottom partners are anticipated by heavy quark flavor symmetry. Here we study the photoproduction of these exotic states and investigate carefully the background from Pomeron exchange. Our results indicate that the maximal photoproduction cross section of strange partner is around 1 $\sim$ 2 orders of magnitude smaller than that of the corresponding non-strange states. The possibility of searching for them in future electron-ion colliders (EIC) is briefly discussed.
2010.04045
Jialun Ping
Yue Tan, Jialun Ping
X(2900) in a chiral quark model
7 pages, 4 figures
null
10.1088/1674-1137/ac0ba4
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Recently, the LHCb Collaboration reported their observation of the first two fully open-flavor tetraquark states named $X_0(2900)$ and $X_1(2900)$ with unknown parity. Inspired by the report, we consider all of possible four-quark candidates of $X(2900)$ including molecular structure and diquark structure in a chiral quark model with the help of Gaussian expansion method. Two different structures coupling is also considered. To identify the genuine resonances, real-scaling method (stabilization method) was employed. The results show that no candidate of $X(2900)$ is founded in $00^+$ and $01^+$ $cs\bar{q}\bar{q}$ system below the threshold of $D^*\bar{K}^*$, while there are two states in the $P$-wave excited $cs\bar{q}\bar{q}$ system, $D_1\bar{K}$ and $D_J\bar{K}$, which could be candidates of $X(2900)$. In this way, we assign negative parity to $X_1(2900)$, and $X_0(2900)$ maybe a resonance state above the threshold of $D^*\bar{K}^*$, more calculation is needed.
[ { "created": "Thu, 8 Oct 2020 15:12:41 GMT", "version": "v1" }, { "created": "Sat, 10 Oct 2020 00:56:38 GMT", "version": "v2" } ]
2021-09-22
[ [ "Tan", "Yue", "" ], [ "Ping", "Jialun", "" ] ]
Recently, the LHCb Collaboration reported their observation of the first two fully open-flavor tetraquark states named $X_0(2900)$ and $X_1(2900)$ with unknown parity. Inspired by the report, we consider all of possible four-quark candidates of $X(2900)$ including molecular structure and diquark structure in a chiral quark model with the help of Gaussian expansion method. Two different structures coupling is also considered. To identify the genuine resonances, real-scaling method (stabilization method) was employed. The results show that no candidate of $X(2900)$ is founded in $00^+$ and $01^+$ $cs\bar{q}\bar{q}$ system below the threshold of $D^*\bar{K}^*$, while there are two states in the $P$-wave excited $cs\bar{q}\bar{q}$ system, $D_1\bar{K}$ and $D_J\bar{K}$, which could be candidates of $X(2900)$. In this way, we assign negative parity to $X_1(2900)$, and $X_0(2900)$ maybe a resonance state above the threshold of $D^*\bar{K}^*$, more calculation is needed.
1807.04055
Jyoti Saini
Suman Kumbhakar and Jyoti Saini
New physics effects in purely leptonic $B^*_s$ decays
8 pages, 2 figure; discussion added for complex new physics couplings, accepted in Eur. Phys. J. C
null
10.1140/epjc/s10052-019-6901-6
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Recently several measurements in the neutral current sector $b\rightarrow s l^+l^-$ ($l=e$ or $\mu$) as well as in the charged current sector $b \rightarrow c \tau \bar{\nu}$ show significant deviations from their Standard Model predictions. It has been shown that two different new physics solutions can explain all the anomalies in $b\rightarrow s l^+l^-$ sector. Both these solutions are in the form of linear combinations of the two operators $(\bar{s}\gamma^{\alpha}P_Lb)(\bar{\mu}\gamma_{\alpha}\mu)$ and $(\bar{s}\gamma^{\alpha}P_Lb)(\bar{\mu}\gamma_{\alpha}\gamma_5\mu)$. We show that the longitudinal polarization asymmetry of the muons in $B^*_s\rightarrow \mu^+\,\mu^-$ decay is a good discriminant between the two solutions if it can be measured to a precision of $10\%$, provided the new physics Wilson coefficients are real. If they are complex, the theoretical uncertainties in this asymmetry are too large to provide effective discrimination. We also investigate the potential impact of $b \rightarrow c \tau \bar{\nu}$ anomalies on $b \rightarrow s \tau^+ \tau^-$ transitions. We consider a model where the new phyics contributions to these two transitions are strongly correlated. We find that the branching ratio of $B^*_s\rightarrow \tau^+\,\tau^-$ can be enhanced by three orders of magnitude.
[ { "created": "Wed, 11 Jul 2018 10:19:26 GMT", "version": "v1" }, { "created": "Thu, 9 Aug 2018 10:48:37 GMT", "version": "v2" }, { "created": "Wed, 10 Oct 2018 11:45:49 GMT", "version": "v3" }, { "created": "Sun, 28 Apr 2019 09:22:08 GMT", "version": "v4" } ]
2019-05-22
[ [ "Kumbhakar", "Suman", "" ], [ "Saini", "Jyoti", "" ] ]
Recently several measurements in the neutral current sector $b\rightarrow s l^+l^-$ ($l=e$ or $\mu$) as well as in the charged current sector $b \rightarrow c \tau \bar{\nu}$ show significant deviations from their Standard Model predictions. It has been shown that two different new physics solutions can explain all the anomalies in $b\rightarrow s l^+l^-$ sector. Both these solutions are in the form of linear combinations of the two operators $(\bar{s}\gamma^{\alpha}P_Lb)(\bar{\mu}\gamma_{\alpha}\mu)$ and $(\bar{s}\gamma^{\alpha}P_Lb)(\bar{\mu}\gamma_{\alpha}\gamma_5\mu)$. We show that the longitudinal polarization asymmetry of the muons in $B^*_s\rightarrow \mu^+\,\mu^-$ decay is a good discriminant between the two solutions if it can be measured to a precision of $10\%$, provided the new physics Wilson coefficients are real. If they are complex, the theoretical uncertainties in this asymmetry are too large to provide effective discrimination. We also investigate the potential impact of $b \rightarrow c \tau \bar{\nu}$ anomalies on $b \rightarrow s \tau^+ \tau^-$ transitions. We consider a model where the new phyics contributions to these two transitions are strongly correlated. We find that the branching ratio of $B^*_s\rightarrow \tau^+\,\tau^-$ can be enhanced by three orders of magnitude.
hep-ph/9607359
null
S.M. Barr (Bartol Res. Inst.)
The Stability of the Gauge Hierarchy in $SU(5) \times SU(5)$
13 pages, LaTeX
Phys.Rev.D55:6775-6779,1997
10.1103/PhysRevD.55.6775
BA-95-31
hep-ph
null
It has been shown that the Dimopoulos-Wilczek (or missing-VEV) mechanism for doublet-triplet splitting can be implemented in $SU(5) \times SU(5)$ models, which requires no adjoint Higgs fields. This is an advantage from the point of view of string theory construction. Here the stability of the gauge hierarchy is examined in detail, and it is shown that it can be guaranteed much more simply than in $SO(10)$. In fact a $Z_2$ symmetry ensures the stability of the DW form of the expectation values to all orders in GUT-scale VEVs. It is also shown that models based on $SO(10) \times SU(5)$ have the advantages of $SU(5) \times SU(5)$ while permitting complete quark-lepton unification as in $SO(10)$.
[ { "created": "Wed, 17 Jul 1996 18:43:37 GMT", "version": "v1" } ]
2011-05-12
[ [ "Barr", "S. M.", "", "Bartol Res. Inst." ] ]
It has been shown that the Dimopoulos-Wilczek (or missing-VEV) mechanism for doublet-triplet splitting can be implemented in $SU(5) \times SU(5)$ models, which requires no adjoint Higgs fields. This is an advantage from the point of view of string theory construction. Here the stability of the gauge hierarchy is examined in detail, and it is shown that it can be guaranteed much more simply than in $SO(10)$. In fact a $Z_2$ symmetry ensures the stability of the DW form of the expectation values to all orders in GUT-scale VEVs. It is also shown that models based on $SO(10) \times SU(5)$ have the advantages of $SU(5) \times SU(5)$ while permitting complete quark-lepton unification as in $SO(10)$.
hep-ph/0412302
Ramona Vogt
R. Vogt
Open and Hidden Charm Production in d$A$ Collisions at RHIC and LHC
6 pages, 4 figures, European Physics Journal conference proceedings style files included, in proceedings of Hard Probes, 2004 Ericeira, Portugal
Eur.Phys.J.C43:113-119,2005
10.1140/epjc/s2005-02220-3
null
hep-ph
null
We discuss aspects of open and hidden charm production in deuterium-nucleus collisions at RHIC and LHC energies. We describe calculations of the total $c \bar c$ cross section and the charm quark transverse momentum distributions. We next explain how shadowing and moderate nuclear absorption can explain the PHENIX $J/\psi$ dAu/$pp$ ratios and predict the combined effect of shadowing and absorption in 6.2 TeV d+Pb collisions.
[ { "created": "Tue, 21 Dec 2004 00:49:22 GMT", "version": "v1" } ]
2009-01-07
[ [ "Vogt", "R.", "" ] ]
We discuss aspects of open and hidden charm production in deuterium-nucleus collisions at RHIC and LHC energies. We describe calculations of the total $c \bar c$ cross section and the charm quark transverse momentum distributions. We next explain how shadowing and moderate nuclear absorption can explain the PHENIX $J/\psi$ dAu/$pp$ ratios and predict the combined effect of shadowing and absorption in 6.2 TeV d+Pb collisions.
1801.01718
Tanmay Maji
Tanmay Maji and Dipankar Chakrabarti
Parton distribution functions of proton in a light-front quark-diquark model
XXII DAE-BRNS High Energy Physics Symposium, December 12-16, 2016, University of Delhi, India; 4 pages, 1 figure
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present the parton distribution functions (PDFs) for un- polarised, longitudinally polarized and transversely polarized quarks in a proton using the light-front quark diquark model. We also present the scale evolution of PDFs and calculate axial charge and tecsor charge for $u$ and $d$ quarks at a scale of experimental findings.
[ { "created": "Fri, 5 Jan 2018 11:23:20 GMT", "version": "v1" } ]
2018-01-08
[ [ "Maji", "Tanmay", "" ], [ "Chakrabarti", "Dipankar", "" ] ]
We present the parton distribution functions (PDFs) for un- polarised, longitudinally polarized and transversely polarized quarks in a proton using the light-front quark diquark model. We also present the scale evolution of PDFs and calculate axial charge and tecsor charge for $u$ and $d$ quarks at a scale of experimental findings.
1609.05213
Tom\'a\v{s} Brauner
Tomas Brauner and Naoki Yamamoto
Chiral Soliton Lattice and Charged Pion Condensation in Strong Magnetic Fields
v2: 19 pages, 6 figures; substantially extended version of the paper, published in JHEP
null
10.1007/JHEP04(2017)132
null
hep-ph cond-mat.str-el hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Chiral Soliton Lattice (CSL) is a state with a periodic array of topological solitons that spontaneously breaks parity and translational symmetries. Such a state is known to appear in chiral magnets. We show that CSL also appears as a ground state of quantum chromodynamics at nonzero chemical potential in a magnetic field. By analyzing the fluctuations of the CSL, we furthermore demonstrate that in strong but achievable magnetic fields, charged pions undergo Bose-Einstein condensation. Our results, based on a systematic low-energy effective theory, are model-independent and fully analytic.
[ { "created": "Fri, 16 Sep 2016 20:00:05 GMT", "version": "v1" }, { "created": "Fri, 21 Apr 2017 12:32:06 GMT", "version": "v2" } ]
2017-04-24
[ [ "Brauner", "Tomas", "" ], [ "Yamamoto", "Naoki", "" ] ]
The Chiral Soliton Lattice (CSL) is a state with a periodic array of topological solitons that spontaneously breaks parity and translational symmetries. Such a state is known to appear in chiral magnets. We show that CSL also appears as a ground state of quantum chromodynamics at nonzero chemical potential in a magnetic field. By analyzing the fluctuations of the CSL, we furthermore demonstrate that in strong but achievable magnetic fields, charged pions undergo Bose-Einstein condensation. Our results, based on a systematic low-energy effective theory, are model-independent and fully analytic.
1601.05375
David Heymes
Michal Czakon, Paul Fiedler, David Heymes and Alexander Mitov
NNLO QCD predictions for fully-differential top-quark pair production at the Tevatron
38 pages, 13 figures, 13 tables
null
10.1007/JHEP05(2016)034
Cavendish-HEP-16/01, TTK-16-02
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a comprehensive study of differential distributions for Tevatron top-pair events at the level of stable top quarks. All calculations are performed in NNLO QCD with the help of a fully differential partonic Monte-Carlo and are exact at this order in perturbation theory. We present predictions for all kinematic distributions for which data exists. Particular attention is paid on the top-quark forward-backward asymmetry which we study in detail. We compare the NNLO results with existing approximate NNLO predictions as well as differential distributions computed with different parton distribution sets. Theory errors are significantly smaller than current experimental ones with overall agreement between theory and data.
[ { "created": "Wed, 20 Jan 2016 19:17:57 GMT", "version": "v1" } ]
2016-05-25
[ [ "Czakon", "Michal", "" ], [ "Fiedler", "Paul", "" ], [ "Heymes", "David", "" ], [ "Mitov", "Alexander", "" ] ]
We present a comprehensive study of differential distributions for Tevatron top-pair events at the level of stable top quarks. All calculations are performed in NNLO QCD with the help of a fully differential partonic Monte-Carlo and are exact at this order in perturbation theory. We present predictions for all kinematic distributions for which data exists. Particular attention is paid on the top-quark forward-backward asymmetry which we study in detail. We compare the NNLO results with existing approximate NNLO predictions as well as differential distributions computed with different parton distribution sets. Theory errors are significantly smaller than current experimental ones with overall agreement between theory and data.
1302.0307
Reinhard Alkofer
Reinhard Alkofer and Mario Mitter
The effect of an infrared divergent quark-antiquark interaction kernel on other Green functions
7 pages, 2figures, talk presented at the Xth Quark Confinement and the Hadron Spectrum, Munich, Germany, 2012
PoS Confinement X (2013) 061
null
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The n-point Green functions of Landau gauge QCD are systematically investigated in a Dyson-Schwinger approach assuming a static linearly rising potential between fundamental color charges. Besides quarks also scalar matter in the fundamental representation is considered. Starting from the hypothesis of an 1/k^4 infrared divergent matter-antimatter vertex restrictions on the general color tensor structure of this divergence are derived. Consequences for the other four-point functions of QCD, resp., scalar QCD, are presented. Hereby Casimir scaling is found. It is shown that possible singular contributions to the three-point functions vanish due to cancellations within the color algebra. On the other hand, higher n-point functions inherit the infrared singularity of the matter-antimatter vertex in certain color channels. The presented results show that linear confinement is consistently possible in a Greens function approach, however, at the expense that the decoupling theorem is circumvented by infrared singularities.
[ { "created": "Fri, 1 Feb 2013 22:24:04 GMT", "version": "v1" } ]
2013-02-05
[ [ "Alkofer", "Reinhard", "" ], [ "Mitter", "Mario", "" ] ]
The n-point Green functions of Landau gauge QCD are systematically investigated in a Dyson-Schwinger approach assuming a static linearly rising potential between fundamental color charges. Besides quarks also scalar matter in the fundamental representation is considered. Starting from the hypothesis of an 1/k^4 infrared divergent matter-antimatter vertex restrictions on the general color tensor structure of this divergence are derived. Consequences for the other four-point functions of QCD, resp., scalar QCD, are presented. Hereby Casimir scaling is found. It is shown that possible singular contributions to the three-point functions vanish due to cancellations within the color algebra. On the other hand, higher n-point functions inherit the infrared singularity of the matter-antimatter vertex in certain color channels. The presented results show that linear confinement is consistently possible in a Greens function approach, however, at the expense that the decoupling theorem is circumvented by infrared singularities.
2204.09012
Pooja Mukherjee
A. H. Ajjath, Pooja Mukherjee, and V. Ravindran
Going beyond Soft plus Virtual
7 pages. Shorter version of the paper with arxiv id 2006.06726. Accepted for publication as a Letter in Physical Review D
null
10.1103/PhysRevD.105.L091503
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a formalism that sums up the soft-virtual (SV) and next-to-SV (NSV) diagonal contributions to inclusive colorless productions in hadron colliders to all orders in perturbative QCD. Using factorisation theorem, renormalisation group invariance and employing the transcendental structure of perturbative results, we show the exponential behavior of soft-collinear function. This allows us to predict certain SV and NSV terms to all orders from lower order information. We also present an integral representation for the coefficient functions which is suitable for Mellin $N$-space resummation.
[ { "created": "Tue, 19 Apr 2022 17:21:04 GMT", "version": "v1" } ]
2022-05-31
[ [ "Ajjath", "A. H.", "" ], [ "Mukherjee", "Pooja", "" ], [ "Ravindran", "V.", "" ] ]
We present a formalism that sums up the soft-virtual (SV) and next-to-SV (NSV) diagonal contributions to inclusive colorless productions in hadron colliders to all orders in perturbative QCD. Using factorisation theorem, renormalisation group invariance and employing the transcendental structure of perturbative results, we show the exponential behavior of soft-collinear function. This allows us to predict certain SV and NSV terms to all orders from lower order information. We also present an integral representation for the coefficient functions which is suitable for Mellin $N$-space resummation.
hep-ph/9601347
null
Wim Beenakker, Geert Jan van Oldenborgh (Univ. Leiden), Jiri Hoogland, Ronald Kleiss (NIKHEF, Amsterdam)
Definitions and upper bounds for unstable boson masses
12 pages, elsart, also available from http://rulgm4.LeidenUniv.nl/preprints.html, added acknowledgements
Phys.Lett. B376 (1996) 136-141
10.1016/0370-2693(96)00282-1
INLO-PUB-01/96, NIKHEF 96/04
hep-ph
null
We consider the problem of a proper definition of the mass of a heavy unstable boson. It is shown how various definitions are related by the renormalization-scheme independence of the full resummed amplitude. This is made explicit for the $W$ boson in the large $N_f$ limit, where we find an upper bound on the peak position of the lineshape and on the mass, provided a sensible definition of the mass is used. In more realistic models, we conjecture that under certain conditions the mass is similarly bounded. Using this approach an upper limit of about 1 TeV on the mass of the Minimal-Standard-Model Higgs boson is found, independent of any breakdown of perturbation theory.
[ { "created": "Fri, 26 Jan 1996 16:28:07 GMT", "version": "v1" }, { "created": "Thu, 1 Feb 1996 09:46:23 GMT", "version": "v2" } ]
2009-10-28
[ [ "Beenakker", "Wim", "", "Univ. Leiden" ], [ "van Oldenborgh", "Geert Jan", "", "Univ. Leiden" ], [ "Hoogland", "Jiri", "", "NIKHEF, Amsterdam" ], [ "Kleiss", "Ronald", "", "NIKHEF, Amsterdam" ] ]
We consider the problem of a proper definition of the mass of a heavy unstable boson. It is shown how various definitions are related by the renormalization-scheme independence of the full resummed amplitude. This is made explicit for the $W$ boson in the large $N_f$ limit, where we find an upper bound on the peak position of the lineshape and on the mass, provided a sensible definition of the mass is used. In more realistic models, we conjecture that under certain conditions the mass is similarly bounded. Using this approach an upper limit of about 1 TeV on the mass of the Minimal-Standard-Model Higgs boson is found, independent of any breakdown of perturbation theory.
2312.00619
Meril Reboud
Christoph Hanhart, Stephan K\"urten, M\'eril Reboud, Danny van Dyk
Analysis of the $\psi(3770)$ resonance in line with unitarity and analyticity constraints
v2: Corrected measured ee->DD cross section, leading to better fit quality and smaller branching ratio for psi(3770)->non-DDbar
null
null
EOS-2023-02, IPPP/23/67, P3H-23-091, SI-HEP-2023-26, TUM-HEP-1480/23
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the inclusive and exclusive cross sections of $e^+e^-\to \text{hadrons}$ for center-of-mass energies between 3.70 GeV and 3.83 GeV to infer the mass, width, and couplings of the $\psi(3770)$ resonance. By using a coupled-channel K-matrix approach, we setup our analysis to respect unitarity and the analyticity properties of the underlying scattering amplitudes. We fit several models to the full dataset and identify our nominal results through a statistical model comparison. We find that, accounting for the interplay between the $\psi(2S)$ and the $\psi(3770)$, no further pole is required to describe the $\psi(3770)$ line shape. In particular we derive from the pole location $M_{\psi(3770)} = 3778.8 \pm 0.3$ MeV and $\Gamma_{\psi(3770)} = 25.0 \pm 0.5$ MeV. Moreover, we find the decay to $D^+D^-$ and $D^0\bar{D}^0$ to be consistent with isospin symmetry and derive an upper bound on the branching ratio $\mathcal{B}(\psi(3770) \to \textrm{non-}D\bar{D}) < 6\%$ at $90\%$ probability.
[ { "created": "Fri, 1 Dec 2023 14:33:00 GMT", "version": "v1" }, { "created": "Wed, 10 Apr 2024 15:42:04 GMT", "version": "v2" } ]
2024-04-11
[ [ "Hanhart", "Christoph", "" ], [ "Kürten", "Stephan", "" ], [ "Reboud", "Méril", "" ], [ "van Dyk", "Danny", "" ] ]
We study the inclusive and exclusive cross sections of $e^+e^-\to \text{hadrons}$ for center-of-mass energies between 3.70 GeV and 3.83 GeV to infer the mass, width, and couplings of the $\psi(3770)$ resonance. By using a coupled-channel K-matrix approach, we setup our analysis to respect unitarity and the analyticity properties of the underlying scattering amplitudes. We fit several models to the full dataset and identify our nominal results through a statistical model comparison. We find that, accounting for the interplay between the $\psi(2S)$ and the $\psi(3770)$, no further pole is required to describe the $\psi(3770)$ line shape. In particular we derive from the pole location $M_{\psi(3770)} = 3778.8 \pm 0.3$ MeV and $\Gamma_{\psi(3770)} = 25.0 \pm 0.5$ MeV. Moreover, we find the decay to $D^+D^-$ and $D^0\bar{D}^0$ to be consistent with isospin symmetry and derive an upper bound on the branching ratio $\mathcal{B}(\psi(3770) \to \textrm{non-}D\bar{D}) < 6\%$ at $90\%$ probability.
0708.0232
Marco Radici
Marco Radici, Francesco Conti, Alessandro Bacchetta, Andrea Bianconi
Nucleon Spin Structure with hadronic collisions at COMPASS
talk delivered to the "International Workshop on Structure and Spectroscopy", Freiburg, March 19-21, 2007; 18 pages, RevTeX4 style, 8 figures with 10 .eps files
null
null
null
hep-ph
null
In order to illustrate the capabilities of COMPASS using a hadronic beam, I review some of the azimuthal asymmetries in hadronic collisions, that allow for the extraction of transversity, Sivers and Boer-Mulders functions, necessary to explore the partonic spin structure of the nucleon. I also report on some Monte Carlo simulations of such asymmetries for the production of Drell-Yan lepton pairs from the collision of high-energy pions on a transversely polarized proton target.
[ { "created": "Wed, 1 Aug 2007 21:03:10 GMT", "version": "v1" } ]
2007-08-03
[ [ "Radici", "Marco", "" ], [ "Conti", "Francesco", "" ], [ "Bacchetta", "Alessandro", "" ], [ "Bianconi", "Andrea", "" ] ]
In order to illustrate the capabilities of COMPASS using a hadronic beam, I review some of the azimuthal asymmetries in hadronic collisions, that allow for the extraction of transversity, Sivers and Boer-Mulders functions, necessary to explore the partonic spin structure of the nucleon. I also report on some Monte Carlo simulations of such asymmetries for the production of Drell-Yan lepton pairs from the collision of high-energy pions on a transversely polarized proton target.
1303.5299
Andrew Papanastasiou
P. Falgari, A.S. Papanastasiou, A. Signer
Finite-width effects in unstable-particle production at hadron colliders
41 pages, 18 figures, 2 tables
null
10.1007/JHEP05(2013)156
ITP-UU-13/04, SPIN-13/02, DESY 13-049, PSI-PR-13-05, ZU-TH 06/13
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a general formalism for the calculation of finite-width contributions to the differential production cross sections of unstable particles at hadron colliders. In this formalism, which employs an effective-theory description of unstable-particle production and decay, the matrix element computation is organized as a gauge-invariant expansion in powers of $\Gamma_X/m_X$, with $\Gamma_X$ and $m_X$ the width and mass of the unstable particle. This framework allows for a systematic inclusion of off-shell and non-factorizable effects whilst at the same time keeping the computational effort minimal compared to a full calculation in the complex-mass scheme. As a proof-of-concept example, we give results for an NLO calculation of top-antitop production in the $q \bar{q}$ partonic channel. As already found in a similar calculation of single-top production, the finite-width effects are small for the total cross section, as expected from the na\" ive counting $\sim \Gamma_t/m_t \sim 1%$. However, they can be sizeable, in excess of 10%, close to edges of certain kinematical distributions. The dependence of the results on the mass renormalization scheme, and its implication for a precise extraction of the top-quark mass, is also discussed.
[ { "created": "Thu, 21 Mar 2013 15:33:52 GMT", "version": "v1" } ]
2015-06-15
[ [ "Falgari", "P.", "" ], [ "Papanastasiou", "A. S.", "" ], [ "Signer", "A.", "" ] ]
We present a general formalism for the calculation of finite-width contributions to the differential production cross sections of unstable particles at hadron colliders. In this formalism, which employs an effective-theory description of unstable-particle production and decay, the matrix element computation is organized as a gauge-invariant expansion in powers of $\Gamma_X/m_X$, with $\Gamma_X$ and $m_X$ the width and mass of the unstable particle. This framework allows for a systematic inclusion of off-shell and non-factorizable effects whilst at the same time keeping the computational effort minimal compared to a full calculation in the complex-mass scheme. As a proof-of-concept example, we give results for an NLO calculation of top-antitop production in the $q \bar{q}$ partonic channel. As already found in a similar calculation of single-top production, the finite-width effects are small for the total cross section, as expected from the na\" ive counting $\sim \Gamma_t/m_t \sim 1%$. However, they can be sizeable, in excess of 10%, close to edges of certain kinematical distributions. The dependence of the results on the mass renormalization scheme, and its implication for a precise extraction of the top-quark mass, is also discussed.
1203.0230
Mindaugas Karciauskas Dr.
Konstantinos Dimopoulos and Mindaugas Karciauskas
Parity Violating Statistical Anisotropy
Accepted for publication in JHEP
null
10.1007/JHEP06(2012)040
null
hep-ph astro-ph.CO hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Particle production of an Abelian vector boson field with an axial coupling is investigated. The conditions for the generation of scale invariant spectra for the vector field transverse components are obtained. If the vector field contributes to the curvature perturbation in the Universe, scale-invariant particle production enables it to give rise to statistical anisotropy in the spectrum and bispectrum of cosmological perturbations. The axial coupling allows particle production to be parity violating, which in turn can generate parity violating signatures in the bispectrum. The conditions for parity violation are derived and the observational signatures are obtained in the context of the vector curvaton paradigm. Two concrete examples are presented based on realistic particle theory.
[ { "created": "Thu, 1 Mar 2012 16:13:34 GMT", "version": "v1" }, { "created": "Mon, 5 Mar 2012 18:59:56 GMT", "version": "v2" }, { "created": "Tue, 12 Jun 2012 11:06:47 GMT", "version": "v3" } ]
2015-06-04
[ [ "Dimopoulos", "Konstantinos", "" ], [ "Karciauskas", "Mindaugas", "" ] ]
Particle production of an Abelian vector boson field with an axial coupling is investigated. The conditions for the generation of scale invariant spectra for the vector field transverse components are obtained. If the vector field contributes to the curvature perturbation in the Universe, scale-invariant particle production enables it to give rise to statistical anisotropy in the spectrum and bispectrum of cosmological perturbations. The axial coupling allows particle production to be parity violating, which in turn can generate parity violating signatures in the bispectrum. The conditions for parity violation are derived and the observational signatures are obtained in the context of the vector curvaton paradigm. Two concrete examples are presented based on realistic particle theory.
hep-ph/9501396
Martin Bucher
M. Bucher (Princeton U.), A.S. Goldhaber (SUNY-SB), and N. Turok (Princeton U.).
$\Omega_0 <1$ From Inflation
6 pages + 2 postscript figures (uses phyzzx macros) For proceedings of the ASTPART conference held in Stockholm, Sweden in September 1994
Nucl.Phys.Proc.Suppl. 43 (1995) 173-176
10.1016/0920-5632(95)00473-M
null
hep-ph astro-ph
null
An inflationary scenario that leads to $\Omega _0<1$ today is presented. An epoch of `old' inflation during which the smoothness and horizon problems are solved is followed by a shortened epoch of `new' inflation. Old inflation exits through the nucleation of a single bubble, leading to negative spatial curvature on slices of constant cosmic time. We calculate the spectrum of density perturbations in such a scenario.
[ { "created": "Fri, 27 Jan 1995 21:11:59 GMT", "version": "v1" } ]
2016-09-01
[ [ "Bucher", "M.", "", "Princeton U." ], [ "Goldhaber", "A. S.", "", "SUNY-SB" ], [ "Turok", "N.", "", "Princeton U." ], [ ".", "", "" ] ]
An inflationary scenario that leads to $\Omega _0<1$ today is presented. An epoch of `old' inflation during which the smoothness and horizon problems are solved is followed by a shortened epoch of `new' inflation. Old inflation exits through the nucleation of a single bubble, leading to negative spatial curvature on slices of constant cosmic time. We calculate the spectrum of density perturbations in such a scenario.
hep-ph/9605442
Ramon Mendez Galain
I. Bediaga, C. G\"obel (CBPF, Rio, Brasil) and R. M\'endez--Galain (University of Montevideo, Uruguay)
On the Dalitz Plot Approach in Non-leptonic Charm Meson Decays
Version accepted for publication in Physical Review Letters. 9 pages, Latex, including 2 figures
Phys.Rev.Lett. 78 (1997) 22-25
10.1103/PhysRevLett.78.22
null
hep-ph hep-ex
null
We claim that the non-resonant contribution to non-leptonic charm meson decays may not be constant in the phase space of the reaction. We argue that this can be relevant for any weak reaction. We discuss in detail the decay $D^+ \to K^- \pi^+ \pi^+$.
[ { "created": "Thu, 30 May 1996 11:58:00 GMT", "version": "v1" }, { "created": "Tue, 10 Dec 1996 21:57:00 GMT", "version": "v2" } ]
2009-10-28
[ [ "Bediaga", "I.", "", "CBPF, Rio, Brasil" ], [ "Göbel", "C.", "", "CBPF, Rio, Brasil" ], [ "Méndez--Galain", "R.", "", "University of Montevideo, Uruguay" ] ]
We claim that the non-resonant contribution to non-leptonic charm meson decays may not be constant in the phase space of the reaction. We argue that this can be relevant for any weak reaction. We discuss in detail the decay $D^+ \to K^- \pi^+ \pi^+$.
hep-ph/9507452
Koichi Funakubo
K.Funakubo, A.Kakuto, S.Otsuki, K.Takenaga and F.Toyoda
CP-Violating Profile of the Electroweak Bubble Wall
22 pages, latex, 6 figures (included)
Prog.Theor.Phys. 94 (1995) 845-860
10.1143/PTP.94.845
SAGA-HE-89, YITP/K-1115
hep-ph
null
In any scenario of the electroweak baryogenesis, the profile of the CP violating bubble wall, created at the first-order phase transition, plays an essential role. We attempt to determine it by solving the equations of motion for the scalars in the two-Higgs-doublet model at the transition temperature. According to the parameters in the potential, we found three solutions. Two of them smoothly connect the CP-violating broken phase and the symmetric phase, while the other connects CP-conserving vacua but violates CP in the intermediate region. We also estimate the chiral charge flux, which will be turned into the baryon density in the symmetric phase by the sphaleron process.
[ { "created": "Sat, 29 Jul 1995 07:45:34 GMT", "version": "v1" } ]
2009-10-28
[ [ "Funakubo", "K.", "" ], [ "Kakuto", "A.", "" ], [ "Otsuki", "S.", "" ], [ "Takenaga", "K.", "" ], [ "Toyoda", "F.", "" ] ]
In any scenario of the electroweak baryogenesis, the profile of the CP violating bubble wall, created at the first-order phase transition, plays an essential role. We attempt to determine it by solving the equations of motion for the scalars in the two-Higgs-doublet model at the transition temperature. According to the parameters in the potential, we found three solutions. Two of them smoothly connect the CP-violating broken phase and the symmetric phase, while the other connects CP-conserving vacua but violates CP in the intermediate region. We also estimate the chiral charge flux, which will be turned into the baryon density in the symmetric phase by the sphaleron process.
2009.03067
Yi-Lun Du
Yi-Lun Du
Heavy quark radiative energy loss in nuclei within the improved high-twist approach
6 pages, 4 figures, 10th International Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collisions (Hard Probes 2020)
null
10.22323/1.387.0184
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this proceedings, we review our recent work on the heavy quark radiative energy loss in nuclei due to multiple parton scattering within the recently improved high-twist approach, where gauge invariance can be ensured by a delicate setup of the initial partons' transverse momenta. Our new result is consistent with the previous calculations of light quark energy loss in the massless limit and heavy quark energy loss in the soft gluon radiation limit, respectively. We show numerically the correction to the heavy quark energy loss as compared with previous result and with soft gluon radiation approximation. The necessity to go beyond soft gluon radiation limit is demonstrated for a global description of light and heavy flavor data in heavy-ion collisions.
[ { "created": "Mon, 7 Sep 2020 12:47:39 GMT", "version": "v1" } ]
2022-09-21
[ [ "Du", "Yi-Lun", "" ] ]
In this proceedings, we review our recent work on the heavy quark radiative energy loss in nuclei due to multiple parton scattering within the recently improved high-twist approach, where gauge invariance can be ensured by a delicate setup of the initial partons' transverse momenta. Our new result is consistent with the previous calculations of light quark energy loss in the massless limit and heavy quark energy loss in the soft gluon radiation limit, respectively. We show numerically the correction to the heavy quark energy loss as compared with previous result and with soft gluon radiation approximation. The necessity to go beyond soft gluon radiation limit is demonstrated for a global description of light and heavy flavor data in heavy-ion collisions.
hep-ph/9907282
Steve K. Lamoreaux
S.K. Lamoreaux, R. Golub
Comment on "New Experimental Limit for the Electric Dipole Moment of the Neutron"
7 pages, 2 figures
Phys.Rev.D61:051301,2000
10.1103/PhysRevD.61.051301
LA-UR-99-3043
hep-ph
null
A new limit for the neutron electric dipole moment has been recently reported. This new limit is obtained by combining the result from a previous experiment with the result from a more recent experiment that has much worse statistical accuracy. We show that the old result has a systematic error possibly four times greater than the new limit, and under the circumstances, averaging of the old and new results is statistically invalid. The conclusion is that it would be more appropriate to quote two independent but mutually supportive limits as obtained from each experiment separately.
[ { "created": "Thu, 8 Jul 1999 20:18:03 GMT", "version": "v1" } ]
2008-11-26
[ [ "Lamoreaux", "S. K.", "" ], [ "Golub", "R.", "" ] ]
A new limit for the neutron electric dipole moment has been recently reported. This new limit is obtained by combining the result from a previous experiment with the result from a more recent experiment that has much worse statistical accuracy. We show that the old result has a systematic error possibly four times greater than the new limit, and under the circumstances, averaging of the old and new results is statistically invalid. The conclusion is that it would be more appropriate to quote two independent but mutually supportive limits as obtained from each experiment separately.
hep-ph/0407234
Kai Wang
Kai Wang
Hidden symmetries and their implications for Particle Physics
LaTeX, 62 pages. Thesis submitted for the degree of Master of Sciences at Oklahoma State University. Thesis advisor: K.S. Babu
null
null
null
hep-ph
null
In this thesis, we study the hidden symmetries in the SM and also use discrete gauge symmetries as model building tools to solve various problems in the SM as well as the MSSM, such as R-parity, mu-term, stabilizing the axion solutions, etc. The flavor independent non-supersymmetric SM at the renormalizable level has a discrete Z_3 gauge symmetry known as baryon parity. It is anomaly free at the discrete level as a result of the existence of three generations. The symmetry can effectively act as the Baryon number up to the \Delta B=3 mod 3 level which is also consistent with the prediction from non-perturbative processes corrections in the SM, such as electroweak instanton and sphaleron processes. This symmetry is not consistent with the simple GUTs since those theories explicitly break it. Thus this baryon parity provides a strong hint for new physics like GUTs. Quantum mechanically, we estimate the triple nucleon decay rate which is predicted by the existence of this symmetry. We find a simple U(1) realization with the presence of right-handed neutrinos, from which this baryon parity can naturally emerge. Gauged R-parity is studied in the following chapter. We also study various different approaches to the mu-term problem via a symmetry classification. One explicit example in terms of a Z_4 subgroup of the anomalous U(1) symmetry is given. Another solution arises from a SUSY version of QCD invisible axion. Discrete flavor gauge symmetries are discussed to explain the observed hierarchy fermion masses. D-term splitting problem can then be avoided. In the last part, we show how to use discrete gauge symmetries to stabilize the QCD invisible axion solutions, for both DFSZ and KSVZ invisible axion models.
[ { "created": "Tue, 20 Jul 2004 21:33:30 GMT", "version": "v1" } ]
2007-05-23
[ [ "Wang", "Kai", "" ] ]
In this thesis, we study the hidden symmetries in the SM and also use discrete gauge symmetries as model building tools to solve various problems in the SM as well as the MSSM, such as R-parity, mu-term, stabilizing the axion solutions, etc. The flavor independent non-supersymmetric SM at the renormalizable level has a discrete Z_3 gauge symmetry known as baryon parity. It is anomaly free at the discrete level as a result of the existence of three generations. The symmetry can effectively act as the Baryon number up to the \Delta B=3 mod 3 level which is also consistent with the prediction from non-perturbative processes corrections in the SM, such as electroweak instanton and sphaleron processes. This symmetry is not consistent with the simple GUTs since those theories explicitly break it. Thus this baryon parity provides a strong hint for new physics like GUTs. Quantum mechanically, we estimate the triple nucleon decay rate which is predicted by the existence of this symmetry. We find a simple U(1) realization with the presence of right-handed neutrinos, from which this baryon parity can naturally emerge. Gauged R-parity is studied in the following chapter. We also study various different approaches to the mu-term problem via a symmetry classification. One explicit example in terms of a Z_4 subgroup of the anomalous U(1) symmetry is given. Another solution arises from a SUSY version of QCD invisible axion. Discrete flavor gauge symmetries are discussed to explain the observed hierarchy fermion masses. D-term splitting problem can then be avoided. In the last part, we show how to use discrete gauge symmetries to stabilize the QCD invisible axion solutions, for both DFSZ and KSVZ invisible axion models.
2009.01256
Julian Heeck
Julian Heeck
Light particles with baryon and lepton numbers
6 pages, to appear in PLB
Physics Letters B 813 (2021) 136043
10.1016/j.physletb.2020.136043
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider light new particles $\chi$ and $\phi$ that carry baryon and lepton numbers. If these particles are lighter than nucleons they lead to exotic decays such as $p\to \pi^+ \chi$ and $p\to e^+\phi$, not yet fully constrained by dedicated searches. For $\chi$ and $\phi$ masses in the GeV range proton decays are kinematically forbidden but other decays of the forms baryon $\to$ meson$+\chi$, meson $\to$ baryon$+\bar\chi$, and baryon $\to$ anti-lepton$+\phi$ involving heavy initial hadrons are allowed. This opens up the possibility to search for apparent baryon number violation not just in underground experiments such as Super-Kamiokande and DUNE but also in decays of heavy hadrons in charm and B factories.
[ { "created": "Wed, 2 Sep 2020 18:00:10 GMT", "version": "v1" }, { "created": "Mon, 21 Dec 2020 18:54:06 GMT", "version": "v2" } ]
2021-01-01
[ [ "Heeck", "Julian", "" ] ]
We consider light new particles $\chi$ and $\phi$ that carry baryon and lepton numbers. If these particles are lighter than nucleons they lead to exotic decays such as $p\to \pi^+ \chi$ and $p\to e^+\phi$, not yet fully constrained by dedicated searches. For $\chi$ and $\phi$ masses in the GeV range proton decays are kinematically forbidden but other decays of the forms baryon $\to$ meson$+\chi$, meson $\to$ baryon$+\bar\chi$, and baryon $\to$ anti-lepton$+\phi$ involving heavy initial hadrons are allowed. This opens up the possibility to search for apparent baryon number violation not just in underground experiments such as Super-Kamiokande and DUNE but also in decays of heavy hadrons in charm and B factories.
2211.06356
Wolfgang Lucha
Wolfgang Lucha, Dmitri Melikhov, Hagop Sazdjian
Zooming in on Multiquark Hadrons within QCD Sum-Rule Approaches
8 pages, 8 figures, contributed to "XVth Quark Confinement and the Hadron Spectrum" (1 - 6 August 2022, Stavanger, Norway)
EPJ Web of Conferences 274 (2022) 03004
10.1051/epjconf/202227403004
HEPHY-PUB 1033/22 (2022)
hep-ph nucl-th
http://creativecommons.org/licenses/by/4.0/
Aiming at self-consistent descriptions of multiquark hadrons (such as tetraquarks, pentaquarks, hexaquarks) by means of QCD sum rules, we note that the totality of contributions to two-point or three-point correlation functions that involve, respectively, either two or just a single operator capable of interpolating the particular multiquark under study can be straightforwardly disentangled into two disjoint classes defined by unambiguously identifiable members. The first is formed by so-called multiquark-phile contributions which indeed might support multiquarks. In the case of flavour-exotic tetraquarks, by definition composed of four (anti-) quarks of mutually different flavours, a tetraquark-phile contribution has to exhibit two or more gluon exchanges of appropriate topology. The second consists of contributions evidently not bearing any relation to multiquarks; these must be discarded when studying multiquarks by QCD sum rules. The first class only should enter the "multiquark-adequate" QCD sum rules for exotic hadrons.
[ { "created": "Fri, 11 Nov 2022 17:15:15 GMT", "version": "v1" } ]
2023-01-11
[ [ "Lucha", "Wolfgang", "" ], [ "Melikhov", "Dmitri", "" ], [ "Sazdjian", "Hagop", "" ] ]
Aiming at self-consistent descriptions of multiquark hadrons (such as tetraquarks, pentaquarks, hexaquarks) by means of QCD sum rules, we note that the totality of contributions to two-point or three-point correlation functions that involve, respectively, either two or just a single operator capable of interpolating the particular multiquark under study can be straightforwardly disentangled into two disjoint classes defined by unambiguously identifiable members. The first is formed by so-called multiquark-phile contributions which indeed might support multiquarks. In the case of flavour-exotic tetraquarks, by definition composed of four (anti-) quarks of mutually different flavours, a tetraquark-phile contribution has to exhibit two or more gluon exchanges of appropriate topology. The second consists of contributions evidently not bearing any relation to multiquarks; these must be discarded when studying multiquarks by QCD sum rules. The first class only should enter the "multiquark-adequate" QCD sum rules for exotic hadrons.
1507.05768
Pere Masjuan
H. Czy\.z (ed.), S. Eidelman, A. Hafner, C.F. Redmer, P.A. Lukin, T. Ferber, P. Masjuan (ed.), K. Ko{\l}odziej, O. Shekhovtsova, G. Venanzoni (ed.)
Mini-Proceedings, 17th meeting of the Working Group on Radiative Corrections and MC Generators for Low Energies
28 pages, 10 contributions. Editors: H. Czyz, P. Masjuan, and G. Venanzoni
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The mini-proceedings of the 17$^{\mathrm{th}}$ Meeting of the "Working Group on Radiative Corrections and MonteCarlo Generators for Low Energies" held in Frascati, 20$^{\mathrm{th}}$ - 21$^{\mathrm{st}}$ April, are presented. These meetings, started in 2006, have as aim to bring together experimentalists and theoreticians working in the fields of meson transition form factors, hadronic contributions to the anomalous magnetic moment of the leptons, and the effective fine structure constant. The development of MonteCarlo generators and Radiative Corrections for precision $e^+e^-$ and $\tau$-lepton physics are also covered, with emphasis on meson production. Heavy quark masses were covered as well in this edition.
[ { "created": "Tue, 21 Jul 2015 10:01:47 GMT", "version": "v1" } ]
2015-07-22
[ [ "Czyż", "H.", "", "ed." ], [ "Eidelman", "S.", "", "ed." ], [ "Hafner", "A.", "", "ed." ], [ "Redmer", "C. F.", "", "ed." ], [ "Lukin", "P. A.", "", "ed." ], [ "Ferber", "T.", "", "ed." ], [ ...
The mini-proceedings of the 17$^{\mathrm{th}}$ Meeting of the "Working Group on Radiative Corrections and MonteCarlo Generators for Low Energies" held in Frascati, 20$^{\mathrm{th}}$ - 21$^{\mathrm{st}}$ April, are presented. These meetings, started in 2006, have as aim to bring together experimentalists and theoreticians working in the fields of meson transition form factors, hadronic contributions to the anomalous magnetic moment of the leptons, and the effective fine structure constant. The development of MonteCarlo generators and Radiative Corrections for precision $e^+e^-$ and $\tau$-lepton physics are also covered, with emphasis on meson production. Heavy quark masses were covered as well in this edition.
2203.06988
Minoru Tanaka
Motomichi Tashiro, Noboru Sasao and Minoru Tanaka
Generation of Twisted Gamma-Rays via Two-Photon Transition
20 pages, 11 figures
null
10.1002/andp.202200168
OU-HET-1136
hep-ph physics.acc-ph physics.atom-ph
http://creativecommons.org/licenses/by/4.0/
We present a new and efficient method of generating twisted gamma rays utilizing highly accelerated helium-like ions; they are excited to a chosen state by irradiating two optical lasers and emit a photon with orbital angular momentum in the deexcitation process. We study its emission rate together with other properties such as background and photo-ionization processes.
[ { "created": "Mon, 14 Mar 2022 10:46:51 GMT", "version": "v1" } ]
2022-08-24
[ [ "Tashiro", "Motomichi", "" ], [ "Sasao", "Noboru", "" ], [ "Tanaka", "Minoru", "" ] ]
We present a new and efficient method of generating twisted gamma rays utilizing highly accelerated helium-like ions; they are excited to a chosen state by irradiating two optical lasers and emit a photon with orbital angular momentum in the deexcitation process. We study its emission rate together with other properties such as background and photo-ionization processes.
1402.0762
G.R. Boroun
G.R.Boroun
Hard- Pomeron behavior of the Longitudinal Structure Function $F_{L}$ in the Next- to- Leading- Order at low $x$
10pages,3figures
International Journal of Modern Physics E Vol. 18, No. 1, (2009) 131
10.1142/S0218301309012057
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present an analytic formula to extract the longitudinal structure function in the next- to -leading order of the perturbation theory at low $x$, from the Regge- like behavior of the gluon distribution and the structure function at this limit. In this approach, the longitudinal structure function has the hard- Pomeron behavior. The determined values are compared with the $H1$ data and MRST model. All results can consistently be described within the framework of perturbative QCD which essentially show increases as $x$ decreases.
[ { "created": "Tue, 4 Feb 2014 15:25:41 GMT", "version": "v1" } ]
2015-06-18
[ [ "Boroun", "G. R.", "" ] ]
We present an analytic formula to extract the longitudinal structure function in the next- to -leading order of the perturbation theory at low $x$, from the Regge- like behavior of the gluon distribution and the structure function at this limit. In this approach, the longitudinal structure function has the hard- Pomeron behavior. The determined values are compared with the $H1$ data and MRST model. All results can consistently be described within the framework of perturbative QCD which essentially show increases as $x$ decreases.
2403.04068
Davide Germani
Davide Germani, Farhad Niliani, Antonio D. Polosa
A Simple Model of Pentaquarks
14 pages, 2 figures
Eur. Phys. J. C 84, 755 (2024)
10.1140/epjc/s10052-024-13103-y
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
We describe pentaquarks as baryo-charmonia with a color octet $c\bar{c}$ core bonded to a color octet three-quark system. Fermi statistics of the light quark cloud allows to describe two pentaquark triplets: a lower one, well supported by experiment, and a higher one with strangeness. For the time being, the lowest line of the strange triplet has been experimentally identified in a $3\sigma$ peak. Data also suggest (at least) two different production mechanisms for pentaquarks. We show how this can be described in the proposed scheme.
[ { "created": "Wed, 6 Mar 2024 21:42:57 GMT", "version": "v1" }, { "created": "Tue, 30 Jul 2024 09:21:47 GMT", "version": "v2" } ]
2024-07-31
[ [ "Germani", "Davide", "" ], [ "Niliani", "Farhad", "" ], [ "Polosa", "Antonio D.", "" ] ]
We describe pentaquarks as baryo-charmonia with a color octet $c\bar{c}$ core bonded to a color octet three-quark system. Fermi statistics of the light quark cloud allows to describe two pentaquark triplets: a lower one, well supported by experiment, and a higher one with strangeness. For the time being, the lowest line of the strange triplet has been experimentally identified in a $3\sigma$ peak. Data also suggest (at least) two different production mechanisms for pentaquarks. We show how this can be described in the proposed scheme.
hep-ph/0009094
Erhan Iltan
A. Goksu (METU, Ankara), E. O. Iltan (METU, Ankara) and L. Solmaz (METU, Ankara)
b --> s g g decay in the two and three Higgs doublet models with CP violating effects
15 pages, 7 Figures (required epsf style)
Int.J.Mod.Phys. A16 (2001) 1759-1774
10.1142/S0217751X0100338X
null
hep-ph
null
We study the decay width and CP-asymmetry of the inclusive process b--> s g g (g denotes gluon) in the three and two Higgs doublet models with complex Yukawa couplings. We analyse the dependencies of the differential decay width and CP-asymmetry to the s- quark energy E_s and CP violating parameter \theta. We observe that there exist a considerable enhancement in the decay width and CP asymmetry is at the order of 10^{-2}. Further, it is possible to predict the sign of C_7^{eff} using the CP asymmetry.
[ { "created": "Fri, 8 Sep 2000 10:05:34 GMT", "version": "v1" }, { "created": "Thu, 4 Jan 2001 10:09:32 GMT", "version": "v2" } ]
2009-10-31
[ [ "Goksu", "A.", "", "METU, Ankara" ], [ "Iltan", "E. O.", "", "METU, Ankara" ], [ "Solmaz", "L.", "", "METU, Ankara" ] ]
We study the decay width and CP-asymmetry of the inclusive process b--> s g g (g denotes gluon) in the three and two Higgs doublet models with complex Yukawa couplings. We analyse the dependencies of the differential decay width and CP-asymmetry to the s- quark energy E_s and CP violating parameter \theta. We observe that there exist a considerable enhancement in the decay width and CP asymmetry is at the order of 10^{-2}. Further, it is possible to predict the sign of C_7^{eff} using the CP asymmetry.
1211.5015
Robert Harlander
Lukas Altenkamp, Stefan Dittmaier, Robert V. Harlander, Heidi Rzehak, Tom J. E. Zirke
Gluon-induced Higgs-strahlung at next-to-leading order QCD
30 pages, 8 figures, 2 tables
null
10.1007/JHEP02(2013)078
CERN-PH-TH/2012-312; FR-PHENO-2012-023; WUB/12-21
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Gluon-induced contributions to the associated production of a Higgs and a Z-boson are calculated with NLO accuracy in QCD. They constitute a significant contribution to the cross section for this process. The perturbative correction factor (K-factor) is calculated in the limit of infinite top-quark and vanishing bottom-quark masses. The qualitative similarity of the results to the well-known ones for the gluon-fusion process $gg\to H$ allows to conclude that rescaling the LO prediction by this K-factor leads to a reliable NLO result and realistic error estimate due to missing higher-order perturbative effects. We consider the total inclusive cross section as well as a scenario with a boosted Higgs boson, where the Higgs boson's transverse momentum is restricted to values ptH>200GeV. In both cases, we find large correction factors $K\approx 2$ in most of the parameter space.
[ { "created": "Wed, 21 Nov 2012 12:25:06 GMT", "version": "v1" } ]
2015-06-12
[ [ "Altenkamp", "Lukas", "" ], [ "Dittmaier", "Stefan", "" ], [ "Harlander", "Robert V.", "" ], [ "Rzehak", "Heidi", "" ], [ "Zirke", "Tom J. E.", "" ] ]
Gluon-induced contributions to the associated production of a Higgs and a Z-boson are calculated with NLO accuracy in QCD. They constitute a significant contribution to the cross section for this process. The perturbative correction factor (K-factor) is calculated in the limit of infinite top-quark and vanishing bottom-quark masses. The qualitative similarity of the results to the well-known ones for the gluon-fusion process $gg\to H$ allows to conclude that rescaling the LO prediction by this K-factor leads to a reliable NLO result and realistic error estimate due to missing higher-order perturbative effects. We consider the total inclusive cross section as well as a scenario with a boosted Higgs boson, where the Higgs boson's transverse momentum is restricted to values ptH>200GeV. In both cases, we find large correction factors $K\approx 2$ in most of the parameter space.
hep-ph/0205270
Alexander Belyaev
Alexander Belyaev and Laura Reina
pp -> ttH, H->tau tau: toward a model independent determination of the Higgs boson couplings at the LHC
19 pages, 5 Figures, LaTex, published version, typos corrected, comments added in Sec. 2
JHEP0208:041,2002
10.1088/1126-6708/2002/08/041
FSU-HEP-020523
hep-ph
null
The possibility of detecting a Higgs boson through several production and decay channels is instrumental to the measurement of its couplings. In this paper we study the pp-> ttH(H-> tau tau) channel at the LHC, for the case of a scalar Higgs boson, and use the obtained results to improve on existing strategies toward a model independent determination of the Higgs boson couplings. The case of a scalar Higgs boson with mass below 140 GeV looks particularly promising.
[ { "created": "Thu, 23 May 2002 20:52:32 GMT", "version": "v1" }, { "created": "Wed, 29 May 2002 18:46:55 GMT", "version": "v2" }, { "created": "Fri, 27 Sep 2002 15:18:27 GMT", "version": "v3" } ]
2009-11-07
[ [ "Belyaev", "Alexander", "" ], [ "Reina", "Laura", "" ] ]
The possibility of detecting a Higgs boson through several production and decay channels is instrumental to the measurement of its couplings. In this paper we study the pp-> ttH(H-> tau tau) channel at the LHC, for the case of a scalar Higgs boson, and use the obtained results to improve on existing strategies toward a model independent determination of the Higgs boson couplings. The case of a scalar Higgs boson with mass below 140 GeV looks particularly promising.
1802.03206
Arlene Cristina Aguilar
A. C. Aguilar, A. Doff, A. A. Natale
Perturbative corrections to technicolor
7 pages, 4 figures, expanded version matching the published one
Phys. Rev. D 97, 115035 (2018)
10.1103/PhysRevD.97.115035
null
hep-ph hep-lat hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The full solution of technicolor (TC) Schwinger-Dyson equations should include radiative corrections induced by extended technicolor (ETC) (or other) interactions. We verify that when TC is embedded into a larger theory including also QCD, these radiative corrections couple the different strongly interacting Schwinger-Dyson equations, providing a tiny mass to technifermions and changing the ultraviolet behavior of the gap equation solution. We argue about the origin of the different quark masses without appealing for different ETC boson masses, in one scenario where most of the new physics will appear in interactions with the third fermion generation and with a TC scalar boson possibly lighter than the TC characteristic scale ($\Lambda_{\tt{TC}}$)
[ { "created": "Fri, 9 Feb 2018 11:23:14 GMT", "version": "v1" }, { "created": "Thu, 19 Jul 2018 13:16:14 GMT", "version": "v2" } ]
2018-07-20
[ [ "Aguilar", "A. C.", "" ], [ "Doff", "A.", "" ], [ "Natale", "A. A.", "" ] ]
The full solution of technicolor (TC) Schwinger-Dyson equations should include radiative corrections induced by extended technicolor (ETC) (or other) interactions. We verify that when TC is embedded into a larger theory including also QCD, these radiative corrections couple the different strongly interacting Schwinger-Dyson equations, providing a tiny mass to technifermions and changing the ultraviolet behavior of the gap equation solution. We argue about the origin of the different quark masses without appealing for different ETC boson masses, in one scenario where most of the new physics will appear in interactions with the third fermion generation and with a TC scalar boson possibly lighter than the TC characteristic scale ($\Lambda_{\tt{TC}}$)
1201.1403
Gautam Bhattacharyya
Gautam Bhattacharyya
Electroweak Symmetry Breaking Beyond the Standard Model
Plenary talk at the International Lepton-Photon Conference, Mumbai, August 2011. To appear in the proceedings (special issue of PRAMANA)
null
10.1007/s12043-012-0370-x
SINP/TNP/2012/02
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this talk, I shall address two key issues related to electroweak symmetry breaking. First, how fine-tuned different models are that trigger this phenomenon? Second, even if a light Higgs boson exists, does it have to be necessarily elementary? After a brief introduction, I shall first review the fine-tuning aspects of the MSSM, NMSSM, generalized NMSSM and GMSB scenarios. I shall then compare and contrast the little Higgs, composite Higgs and the Higgsless models. Finally, I shall summarize by giving a broad overview on where we stand at the end of 2011.
[ { "created": "Fri, 6 Jan 2012 12:33:10 GMT", "version": "v1" } ]
2015-06-03
[ [ "Bhattacharyya", "Gautam", "" ] ]
In this talk, I shall address two key issues related to electroweak symmetry breaking. First, how fine-tuned different models are that trigger this phenomenon? Second, even if a light Higgs boson exists, does it have to be necessarily elementary? After a brief introduction, I shall first review the fine-tuning aspects of the MSSM, NMSSM, generalized NMSSM and GMSB scenarios. I shall then compare and contrast the little Higgs, composite Higgs and the Higgsless models. Finally, I shall summarize by giving a broad overview on where we stand at the end of 2011.
1305.4507
Avirup Shaw
Anindya Datta (University of Calcutta), Ujjal Kumar Dey (Harish-Chandra Research Institute), Amitava Raychaudhuri (University of Calcutta), Avirup Shaw (University of Calcutta)
Boundary Localized Terms in Universal Extra-Dimensional Models through a Dark Matter perspective
23 pages including Appendix, 6 figures, Minor typographical improvements,Publish version
Phys. Rev. D 88, 016011 (2013)
10.1103/PhysRevD.88.016011
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In universal extra dimension (UED) models with one compactified extra dimension, a Z_2 symmetry, termed KK-parity, ensures the stability of the lightest Kaluza-Klein particle (LKP). This symmetry leads to two fixed points. In non-minimal versions of UED boundary-localised terms (BLT) for different fields are included at these fixed points and KK-parity may be violated. However, BLTs with same strength at both points induce a new Z_2 symmetry which restores the stability of the LKP. We show that the BLTs serve to relax the bounds set on the compactification scale in UED by the dark matter relic density requirement. At the same time, the precision of the dark matter measurements severely correlates the BLT parameters of gauge bosons and fermions. Depending on the parameter values, the LKP can be chosen to be the level-1 photon, which is essentially the B^(1), or the level-1 Z-boson, basically the W_3^(1). We find that in the latter case the relic density is too small for a W_3^(1) with a \sim 1 TeV mass. We also explore the prospects of direct detection of an LKP which matches the observed dark matter relic density.
[ { "created": "Mon, 20 May 2013 12:00:00 GMT", "version": "v1" }, { "created": "Tue, 28 May 2013 08:10:17 GMT", "version": "v2" }, { "created": "Tue, 30 Jul 2013 08:37:47 GMT", "version": "v3" } ]
2013-07-31
[ [ "Datta", "Anindya", "", "University of Calcutta" ], [ "Dey", "Ujjal Kumar", "", "Harish-Chandra Research Institute" ], [ "Raychaudhuri", "Amitava", "", "University of\n Calcutta" ], [ "Shaw", "Avirup", "", "University of Calcutta" ] ]
In universal extra dimension (UED) models with one compactified extra dimension, a Z_2 symmetry, termed KK-parity, ensures the stability of the lightest Kaluza-Klein particle (LKP). This symmetry leads to two fixed points. In non-minimal versions of UED boundary-localised terms (BLT) for different fields are included at these fixed points and KK-parity may be violated. However, BLTs with same strength at both points induce a new Z_2 symmetry which restores the stability of the LKP. We show that the BLTs serve to relax the bounds set on the compactification scale in UED by the dark matter relic density requirement. At the same time, the precision of the dark matter measurements severely correlates the BLT parameters of gauge bosons and fermions. Depending on the parameter values, the LKP can be chosen to be the level-1 photon, which is essentially the B^(1), or the level-1 Z-boson, basically the W_3^(1). We find that in the latter case the relic density is too small for a W_3^(1) with a \sim 1 TeV mass. We also explore the prospects of direct detection of an LKP which matches the observed dark matter relic density.
2305.14620
ChongYang Liu
ChongYang Liu, XiaoMin Shen, Bin Zhou, Jun Gao
Automated calculation of Jet fragmentation at NLO in QCD
35 pages, 15 figures, 3 tables; comments are welcome
J. High Energ. Phys. 2023, 108 (2023)
10.1007/JHEP09(2023)108
null
hep-ph hep-ex nucl-th
http://creativecommons.org/licenses/by/4.0/
We present FMNLO, a framework to combine general-purpose Monte Carlo generators and fragmentation functions (FFs). It is based on a hybrid scheme of phase-space slicing method and local subtraction method, and accurate to next-to-leading order (NLO) in QCD. The new framework has been interfaced to MG5 aMC@NLO and made publicly available in this work. We demonstrate its unique ability by giving theoretical predictions of various fragmentation measurements at the LHC, followed by comparison with the data. With the help of interpolation techniques, FMNLO allows for fast calculation of fragmentation processes for a large number of different FFs, which makes it a promising tool for future fits of FFs. As an example, we perform a NLO fit of parton fragmentation functions to unidentified charged hadrons using measurements at the LHC. We find the ATLAS data from inclusive dijet production show a strong constraining power. Notable disparities are found between our gluon FF and that of BKK, DSS and NNFF, indicating the necessities of additional constraints and data for gluon fragmentation function.
[ { "created": "Wed, 24 May 2023 01:37:57 GMT", "version": "v1" }, { "created": "Sat, 6 Jan 2024 17:56:21 GMT", "version": "v2" } ]
2024-01-09
[ [ "Liu", "ChongYang", "" ], [ "Shen", "XiaoMin", "" ], [ "Zhou", "Bin", "" ], [ "Gao", "Jun", "" ] ]
We present FMNLO, a framework to combine general-purpose Monte Carlo generators and fragmentation functions (FFs). It is based on a hybrid scheme of phase-space slicing method and local subtraction method, and accurate to next-to-leading order (NLO) in QCD. The new framework has been interfaced to MG5 aMC@NLO and made publicly available in this work. We demonstrate its unique ability by giving theoretical predictions of various fragmentation measurements at the LHC, followed by comparison with the data. With the help of interpolation techniques, FMNLO allows for fast calculation of fragmentation processes for a large number of different FFs, which makes it a promising tool for future fits of FFs. As an example, we perform a NLO fit of parton fragmentation functions to unidentified charged hadrons using measurements at the LHC. We find the ATLAS data from inclusive dijet production show a strong constraining power. Notable disparities are found between our gluon FF and that of BKK, DSS and NNFF, indicating the necessities of additional constraints and data for gluon fragmentation function.
hep-ph/0512002
Baier
V. N. Baier and V. M. Katkov
Coherent and incoherent radiation from high-energy electron and the LPM effect in oriented single crystal
15 pages, 3 figures
Phys.Lett.A353:91-97,2006
10.1016/j.physleta.2005.12.066
null
hep-ph
null
The process of radiation from high-energy electron in oriented single crystal is considered using the method which permits inseparable consideration of both coherent and incoherent mechanisms of photon emission. The total intensity of radiation is calculated. The theory, where the energy loss of projectile has to be taken into account, agrees quite satisfactory with available CERN data. It is shown that the influence of multiple scattering on radiation process is suppressed due to action of crystal field.
[ { "created": "Thu, 1 Dec 2005 06:06:09 GMT", "version": "v1" } ]
2008-11-26
[ [ "Baier", "V. N.", "" ], [ "Katkov", "V. M.", "" ] ]
The process of radiation from high-energy electron in oriented single crystal is considered using the method which permits inseparable consideration of both coherent and incoherent mechanisms of photon emission. The total intensity of radiation is calculated. The theory, where the energy loss of projectile has to be taken into account, agrees quite satisfactory with available CERN data. It is shown that the influence of multiple scattering on radiation process is suppressed due to action of crystal field.
hep-ph/0601164
Andrea Dainese
J. Baines, S.P. Baranov, O. Behnke, J. Bracinik, M. Cacciari, M. Corradi, A. Dainese, S. Diglio, K.J. Eskola, T.O. Eynck, A. Geiser, G. Grindhammer, H. Jung, B.A. Kniehl, V.J. Kolhinen, S. Kretzer, K. Kutak, E. Laenen, Th. Lagouri, A.V. Lipatov, F. Maltoni, A.D. Martin, A. Meyer, A. Morsch, L. Motyka, K. Peters, F. Petrucci, O.I. Piskounova, R. Ranieri, H. Ruiz, M.G. Ryskin, I. Schienbein, J. Smith, M. Smizanska, H. Spiesberger, A. Tonazzo, U. Uwer, M. Verducci, R. Vogt, C. Weiser, N.P. Zotov
Heavy Quarks: Summary Report
98 pages, HERA-LHC Workshop Proceedings: Summary report of Working Group 3, corrected list of authors
null
null
null
hep-ph
null
The present status of the heavy-quark production theory is critically reviewed in the first contribution. The second contribution summarises the present heavy flavour data from HERA and gives an outlook of what can be expected from HERA-II. The potential of the LHC experiments for charm and beauty physics is reviewed in the 3rd contribution. Then the relevance of saturation and small-x effects to heavy quark production at HERA and at the LHC are discussed. The non-perturbative aspects of heavy-quark fragmentation and their relevance to HERA and LHC are discussed in the next contribution. Finally, a comparison of different theoretical predictions for HERA and LHC based on different approaches is presented.
[ { "created": "Mon, 27 Mar 2006 17:05:41 GMT", "version": "v1" }, { "created": "Mon, 19 Mar 2007 13:15:39 GMT", "version": "v2" } ]
2007-05-23
[ [ "Baines", "J.", "" ], [ "Baranov", "S. P.", "" ], [ "Behnke", "O.", "" ], [ "Bracinik", "J.", "" ], [ "Cacciari", "M.", "" ], [ "Corradi", "M.", "" ], [ "Dainese", "A.", "" ], [ "Diglio", "S.", ...
The present status of the heavy-quark production theory is critically reviewed in the first contribution. The second contribution summarises the present heavy flavour data from HERA and gives an outlook of what can be expected from HERA-II. The potential of the LHC experiments for charm and beauty physics is reviewed in the 3rd contribution. Then the relevance of saturation and small-x effects to heavy quark production at HERA and at the LHC are discussed. The non-perturbative aspects of heavy-quark fragmentation and their relevance to HERA and LHC are discussed in the next contribution. Finally, a comparison of different theoretical predictions for HERA and LHC based on different approaches is presented.
1806.04427
Maxim V. Polyakov
Maxim V. Polyakov, Hyeon-Dong Son, Bao-Dong Sun, Asli Tandogan
$\Omega(2012)$ through the looking glass of flavour SU(3)
6 pages, discussion of the Omega(2012) width in the molecular picture is added
null
10.1016/j.physletb.2019.03.054
null
hep-ph hep-ex nucl-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We perform the flavour $SU(3)$ analysis of the recently discovered $\Omega(2012)$ hyperon. We find that well known (four star) $\Delta(1700)$ resonance with quantum numbers of $J^P=3/2^-$ is a good candidate for the decuplet partner of $\Omega(2012)$ if the branching for the three-body decays of the latter is not too large $\le 70$\%. That implies that the quantum numbers of $\Omega(2012)$ are $I(J^P)=0(3/2^-)$. The predictions for the properties of still missing $\Sigma$ and $\Xi$ decuplet members are made. We also discuss the implications of the ${ \overline{ K} \Xi(1530)}$ molecular picture of $\Omega(2012)$. Crucial experimental tests to distinguish various pictures of $\Omega(2012)$ are suggested.
[ { "created": "Tue, 12 Jun 2018 10:05:03 GMT", "version": "v1" }, { "created": "Sun, 8 Jul 2018 06:57:24 GMT", "version": "v2" }, { "created": "Wed, 11 Jul 2018 18:24:04 GMT", "version": "v3" } ]
2019-04-10
[ [ "Polyakov", "Maxim V.", "" ], [ "Son", "Hyeon-Dong", "" ], [ "Sun", "Bao-Dong", "" ], [ "Tandogan", "Asli", "" ] ]
We perform the flavour $SU(3)$ analysis of the recently discovered $\Omega(2012)$ hyperon. We find that well known (four star) $\Delta(1700)$ resonance with quantum numbers of $J^P=3/2^-$ is a good candidate for the decuplet partner of $\Omega(2012)$ if the branching for the three-body decays of the latter is not too large $\le 70$\%. That implies that the quantum numbers of $\Omega(2012)$ are $I(J^P)=0(3/2^-)$. The predictions for the properties of still missing $\Sigma$ and $\Xi$ decuplet members are made. We also discuss the implications of the ${ \overline{ K} \Xi(1530)}$ molecular picture of $\Omega(2012)$. Crucial experimental tests to distinguish various pictures of $\Omega(2012)$ are suggested.
1305.6524
Robert Shrock
Robert Shrock
Study of Scheme Transformations to Remove Higher-Loop Terms in the $\beta$ Function of a Gauge Theory
15 pages
Phys. Rev. D88, 036003 (2013)
10.1103/PhysRevD.88.036003
YITP-SB-13-14
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Since three-loop and higher-loop terms in the $\beta$ function of a gauge theory are scheme-dependent, one can, at least for sufficiently small coupling, carry out a scheme transformation that removes these terms. A basic question concerns the extent to which this can be done at an infrared fixed point of an asymptotically free gauge theory. This is important for quantitative analyses of the scheme dependence of such a fixed point. Here we study a scheme transformation $S_{R,m}$ with $m \ge 2$ that is constructed so as to remove the terms in the beta function at loop order $\ell=3$ to $\ell=m+1$, inclusive. Starting from an arbitrary initial scheme, we present general expressions for the coefficients of terms of loop order $\ell$ in the beta function in the transformed scheme from $\ell=m+2$ up to $\ell=8$. Extending a previous study of $S_{R,2}$, we investigate the range of applicability of the $S_{R,3}$ scheme transformation in an asymptotically free SU($N_c$) gauge theory with an infrared zero in $\beta$ depending on the number, $N_f$, of fermions in the theory. We show that this $S_{R,3}$ scheme transformation can only be applied self-consistently in a restricted range of $N_f$ with a correspondingly small value of infrared fixed-point coupling. We also study the effect of higher-loop terms on the beta function of a U(1) gauge theory.
[ { "created": "Tue, 28 May 2013 15:12:36 GMT", "version": "v1" } ]
2013-08-13
[ [ "Shrock", "Robert", "" ] ]
Since three-loop and higher-loop terms in the $\beta$ function of a gauge theory are scheme-dependent, one can, at least for sufficiently small coupling, carry out a scheme transformation that removes these terms. A basic question concerns the extent to which this can be done at an infrared fixed point of an asymptotically free gauge theory. This is important for quantitative analyses of the scheme dependence of such a fixed point. Here we study a scheme transformation $S_{R,m}$ with $m \ge 2$ that is constructed so as to remove the terms in the beta function at loop order $\ell=3$ to $\ell=m+1$, inclusive. Starting from an arbitrary initial scheme, we present general expressions for the coefficients of terms of loop order $\ell$ in the beta function in the transformed scheme from $\ell=m+2$ up to $\ell=8$. Extending a previous study of $S_{R,2}$, we investigate the range of applicability of the $S_{R,3}$ scheme transformation in an asymptotically free SU($N_c$) gauge theory with an infrared zero in $\beta$ depending on the number, $N_f$, of fermions in the theory. We show that this $S_{R,3}$ scheme transformation can only be applied self-consistently in a restricted range of $N_f$ with a correspondingly small value of infrared fixed-point coupling. We also study the effect of higher-loop terms on the beta function of a U(1) gauge theory.
0803.3257
Yukio Nemoto
Masayasu Harada, Yukio Nemoto
Quasifermion spectrum at finite temperature from coupled Schwinger-Dyson equations for a fermion-boson system
10 pages, 10 figures, minor changes on discussion on renormalization, typos corrected, version to appear in Phys. Rev. D
Phys.Rev.D78:014004,2008
10.1103/PhysRevD.78.014004
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We nonperturbatively investigate a fermion spectrum at finite temperature in a chiral invariant linear sigma model. Coupled Schwinger-Dyson equations for fermion and boson are developed in the real time formalism and solved numerically. From the coupling of a massless fermion with a massive boson, the fermion spectrum shows a three-peak structure at some temperatures even for the strong coupling region. This means that the three-peak structure which was originally found in the one-loop calculation is stable against higher order corrections even in the strong coupling region.
[ { "created": "Sat, 22 Mar 2008 04:11:50 GMT", "version": "v1" }, { "created": "Mon, 30 Jun 2008 15:31:34 GMT", "version": "v2" } ]
2008-11-26
[ [ "Harada", "Masayasu", "" ], [ "Nemoto", "Yukio", "" ] ]
We nonperturbatively investigate a fermion spectrum at finite temperature in a chiral invariant linear sigma model. Coupled Schwinger-Dyson equations for fermion and boson are developed in the real time formalism and solved numerically. From the coupling of a massless fermion with a massive boson, the fermion spectrum shows a three-peak structure at some temperatures even for the strong coupling region. This means that the three-peak structure which was originally found in the one-loop calculation is stable against higher order corrections even in the strong coupling region.
hep-ph/0406205
Vadym Voronyuk
J.Manjavidze and V.Voronyuk
A note about the t`Hooft`s ansatz for SU(N) real time guage theories
null
Phys.Part.Nucl.Lett.3:391-394,2006
10.1134/S1547477106060082
null
hep-ph
null
The t`Hooft's ansatz reduces the classical Yang--Mills theory to the $\lambda\phi^4$ one. It is shown that in the frame of this ansatz the real-time classical solutions for the arbitrary SU(N) gauge group is obtained by embedding $SU(2)\times SU(2)$ into SU(N). It is argued that this group structure is the only possibility in the frame of the considered ansatz. New explicit solutions for SU(3) and SU(5) gauge groups are shown.
[ { "created": "Sat, 19 Jun 2004 08:16:44 GMT", "version": "v1" } ]
2008-11-26
[ [ "Manjavidze", "J.", "" ], [ "Voronyuk", "V.", "" ] ]
The t`Hooft's ansatz reduces the classical Yang--Mills theory to the $\lambda\phi^4$ one. It is shown that in the frame of this ansatz the real-time classical solutions for the arbitrary SU(N) gauge group is obtained by embedding $SU(2)\times SU(2)$ into SU(N). It is argued that this group structure is the only possibility in the frame of the considered ansatz. New explicit solutions for SU(3) and SU(5) gauge groups are shown.
hep-ph/0307227
A. B. Balantekin
A.B. Balantekin, H. Yuksel (Wisconsin U., Madison)
Constraints on Axial Two-Body Currents from Solar Neutrino Data
5 pages of REVTEX4 with 4 figures
Phys.Rev. C68 (2003) 055801
10.1103/PhysRevC.68.055801
null
hep-ph nucl-th
null
We briefly review recent calculations of neutrino deuteron cross sections within the effective field theory and traditional potential model approaches. We summarize recent efforts to determine the counter term describing axial two-body currents, L_{1A}, in the effective field theory approach. We determine the counter term directly from the solar neutrino data and find several, slightly different, ranges of L_{1A} under different sets of assumptions. Our most conservative fit value with the largest uncertainty is L_{1A} = 4.5 +18/-12 fm^3. We show that the contribution of the uncertainty of L_{1A} to the analysis and interpretation of the solar neutrino data measured at the Sudbury Neutrino Observatory is significantly less than the uncertainty coming from the lack of having a better knowledge of \theta_{13}.
[ { "created": "Thu, 17 Jul 2003 18:58:04 GMT", "version": "v1" }, { "created": "Thu, 31 Jul 2003 19:34:16 GMT", "version": "v2" } ]
2009-11-10
[ [ "Balantekin", "A. B.", "", "Wisconsin U., Madison" ], [ "Yuksel", "H.", "", "Wisconsin U., Madison" ] ]
We briefly review recent calculations of neutrino deuteron cross sections within the effective field theory and traditional potential model approaches. We summarize recent efforts to determine the counter term describing axial two-body currents, L_{1A}, in the effective field theory approach. We determine the counter term directly from the solar neutrino data and find several, slightly different, ranges of L_{1A} under different sets of assumptions. Our most conservative fit value with the largest uncertainty is L_{1A} = 4.5 +18/-12 fm^3. We show that the contribution of the uncertainty of L_{1A} to the analysis and interpretation of the solar neutrino data measured at the Sudbury Neutrino Observatory is significantly less than the uncertainty coming from the lack of having a better knowledge of \theta_{13}.
1109.6327
Tom\'a\v{s} Brauner
Haruki Watanabe, Tomas Brauner
On the number of Nambu-Goldstone bosons and its relation to charge densities
9 pages, REVTeX 4.1; v2: Appendix D completely rewritten, numerous other minor modifications throughout the text
Phys.Rev.D84:125013,2011
10.1103/PhysRevD.84.125013
null
hep-ph cond-mat.quant-gas cond-mat.supr-con hep-th quant-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The low-energy physics of systems with spontaneous symmetry breaking is governed by the associated Nambu-Goldstone (NG) bosons. While NG bosons in Lorentz-invariant systems are well understood, the precise characterization of their number and dispersion relations in a general quantum many-body system is still an open problem. An inequality relating the number of NG bosons and their dispersion relations to the number of broken symmetry generators was found by Nielsen and Chadha. In this paper, we give a presumably first example of a system in which the Nielsen-Chadha inequality is actually not saturated. We suggest that the number of NG bosons is exactly equal to the number of broken generators minus the number of pairs of broken generators whose commutator has a nonzero vacuum expectation value. This naturally leads us to a proposal for a different classification of NG bosons.
[ { "created": "Wed, 28 Sep 2011 20:00:08 GMT", "version": "v1" }, { "created": "Thu, 17 Nov 2011 07:25:57 GMT", "version": "v2" } ]
2011-12-12
[ [ "Watanabe", "Haruki", "" ], [ "Brauner", "Tomas", "" ] ]
The low-energy physics of systems with spontaneous symmetry breaking is governed by the associated Nambu-Goldstone (NG) bosons. While NG bosons in Lorentz-invariant systems are well understood, the precise characterization of their number and dispersion relations in a general quantum many-body system is still an open problem. An inequality relating the number of NG bosons and their dispersion relations to the number of broken symmetry generators was found by Nielsen and Chadha. In this paper, we give a presumably first example of a system in which the Nielsen-Chadha inequality is actually not saturated. We suggest that the number of NG bosons is exactly equal to the number of broken generators minus the number of pairs of broken generators whose commutator has a nonzero vacuum expectation value. This naturally leads us to a proposal for a different classification of NG bosons.
1507.07478
Jose Antonio Oller
Ulf-G. Mei{\ss}ner, Jos\'e A. Oller
Testing the $\chi_{c1}\, p$ composite nature of the $P_c(4450)$
6 pages, 2 tables. One more grant is acknowledged
null
null
null
hep-ph hep-ex hep-lat nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Making use of a recently proposed formalism, we analyze the composite nature of the $P_c(4450)$ resonance observed by LHCb. We show that the present data suggest that this state is almost entirely made of a $\chi_{c1}$ and a proton, due to the close proximity to this threshold. This also suppresses the decay modes into other, lighter channels, in our study represented by $J/\Psi p$. We further argue that this is very similar to the case of the scalar meson $f_0(980)$ which is located closely to the $K\bar K$ threshold and has a suppressed decay into the lighter $\pi\pi$ channel.
[ { "created": "Mon, 27 Jul 2015 16:45:26 GMT", "version": "v1" }, { "created": "Tue, 25 Aug 2015 09:04:57 GMT", "version": "v2" } ]
2015-08-26
[ [ "Meißner", "Ulf-G.", "" ], [ "Oller", "José A.", "" ] ]
Making use of a recently proposed formalism, we analyze the composite nature of the $P_c(4450)$ resonance observed by LHCb. We show that the present data suggest that this state is almost entirely made of a $\chi_{c1}$ and a proton, due to the close proximity to this threshold. This also suppresses the decay modes into other, lighter channels, in our study represented by $J/\Psi p$. We further argue that this is very similar to the case of the scalar meson $f_0(980)$ which is located closely to the $K\bar K$ threshold and has a suppressed decay into the lighter $\pi\pi$ channel.
hep-ph/0105331
Massimiliano Grazzini
M. Grazzini
Higgs boson production at Tevatron Run II and LHC
Latex, 4 pages. Invited talk given at the XIII italian meeting on high energy physics ``LEPTRE'', Rome April 18-20 2001, to appear in the proceedings
null
null
null
hep-ph
null
The main production channels of the Higgs boson at hadron colliders are briefly reviewed and recent developments in the calculation of QCD effects are discussed.
[ { "created": "Thu, 31 May 2001 11:27:37 GMT", "version": "v1" } ]
2007-05-23
[ [ "Grazzini", "M.", "" ] ]
The main production channels of the Higgs boson at hadron colliders are briefly reviewed and recent developments in the calculation of QCD effects are discussed.
hep-ph/9709243
Patricia Ball
E. Bagan, P. Ball, V.M. Braun
Radiative Corrections to the Decay $B\to \pi e\nu$ and the Heavy Quark Limit
11 pages Latex + 3 figures; changed one footnote and moved it into main text; enlarged acknowledgements
Phys.Lett.B417:154-162,1998
10.1016/S0370-2693(97)01371-3
NORDITA-97-59/P, UAB-FT-425
hep-ph
null
We calculate radiative corrections to the light-cone sum rule for the semileptonic form factor in $B\to\pi e\nu$ decays and thus remove the major uncertainty in determining the CKM mixing angle $|V_{ub}|$ by this method. We discuss the remaining uncertainties and perspectives for further studies. The structure of the radiative corrections suggests factorization of soft (end-point) and hard rescattering contributions in heavy-to-light decays in the heavy quark limit.
[ { "created": "Thu, 4 Sep 1997 13:53:37 GMT", "version": "v1" }, { "created": "Mon, 8 Sep 1997 13:25:29 GMT", "version": "v2" } ]
2010-11-23
[ [ "Bagan", "E.", "" ], [ "Ball", "P.", "" ], [ "Braun", "V. M.", "" ] ]
We calculate radiative corrections to the light-cone sum rule for the semileptonic form factor in $B\to\pi e\nu$ decays and thus remove the major uncertainty in determining the CKM mixing angle $|V_{ub}|$ by this method. We discuss the remaining uncertainties and perspectives for further studies. The structure of the radiative corrections suggests factorization of soft (end-point) and hard rescattering contributions in heavy-to-light decays in the heavy quark limit.
2404.17459
Maria Lucia Sambataro
Maria Lucia Sambataro (1 and 2), Vincenzo Greco (1 and 2), Gabriele Parisi (1 and 2), Salvatore Plumari (1 and 2) ((1) Department of Physics and Astronomy 'E. Majorana', University of Catania, (2) Laboratori Nazionali del Sud, INFN-LNS)
Quasi particle model vs lattice QCD thermodynamics: extension to $N_f=2+1+1$ flavors and momentum dependent quark masses
15 pages, 17 figures
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In the last decade a Quasi-Particle Model ($QPM$) has supplied the basis for the study of HQ production in ultra-relativistic AA collisions, allowing for a phenomenological estimate of the HQ diffusion coefficient $D_s(T)$. Taking advantage of the new lattice QCD results for the Equation of State (EoS) with 2+1+1 dynamical flavors, we extend our $QPM$ approach from $N_f=2+1$ to $N_f=2+1+1$, in which the charm quark is included. Given an effective coupling $g(T)$ fixed by a fit to the lQCD energy density $\epsilon(T)$, we evaluate the impact of different temperature parametrizations of charm quark mass on EoS and susceptibilities $\chi_q(T)$ of light, $\chi_s(T)$ of strange and $\chi_c(T)$ of charm quarks, the last favouring a charm quark mass increasing toward $T_c$. We also explore the extension of the $QPM$ approach to a more realistic approach, that we label $QPM_p$, in which quark and gluon masses explicitly depend on their momentum converging to the current quark mass at high momenta, as expected from asymptotic free dynamics. The $QPM_p$ is seen to allow for a simultaneous quantitative description not only of the EoS but also of the quark susceptibilities ($\chi_q(T)$, $\chi_s(T)$), which instead are underestimated in the simple $QPM$ model. Furthermore, evaluating the spatial diffusion coefficient $2\pi T D_s(T)$ in the $QPM_p$, we find it is also significantly closer than $QPM$ to the recent lQCD data performed including dynamical fermions. Finally, in a 1+1D expanding system, we evaluate the $R_{AA}(p_T)$ in the $QPM$ and $QPM_p$, finding a significant reduction at low momenta for $QPM_p$ which could lead in a realistic scenario to a better agreement to experimental data.
[ { "created": "Fri, 26 Apr 2024 14:56:49 GMT", "version": "v1" } ]
2024-04-29
[ [ "Sambataro", "Maria Lucia", "", "1 and 2" ], [ "Greco", "Vincenzo", "", "1 and 2" ], [ "Parisi", "Gabriele", "", "1 and 2" ], [ "Plumari", "Salvatore", "", "1 and 2" ] ]
In the last decade a Quasi-Particle Model ($QPM$) has supplied the basis for the study of HQ production in ultra-relativistic AA collisions, allowing for a phenomenological estimate of the HQ diffusion coefficient $D_s(T)$. Taking advantage of the new lattice QCD results for the Equation of State (EoS) with 2+1+1 dynamical flavors, we extend our $QPM$ approach from $N_f=2+1$ to $N_f=2+1+1$, in which the charm quark is included. Given an effective coupling $g(T)$ fixed by a fit to the lQCD energy density $\epsilon(T)$, we evaluate the impact of different temperature parametrizations of charm quark mass on EoS and susceptibilities $\chi_q(T)$ of light, $\chi_s(T)$ of strange and $\chi_c(T)$ of charm quarks, the last favouring a charm quark mass increasing toward $T_c$. We also explore the extension of the $QPM$ approach to a more realistic approach, that we label $QPM_p$, in which quark and gluon masses explicitly depend on their momentum converging to the current quark mass at high momenta, as expected from asymptotic free dynamics. The $QPM_p$ is seen to allow for a simultaneous quantitative description not only of the EoS but also of the quark susceptibilities ($\chi_q(T)$, $\chi_s(T)$), which instead are underestimated in the simple $QPM$ model. Furthermore, evaluating the spatial diffusion coefficient $2\pi T D_s(T)$ in the $QPM_p$, we find it is also significantly closer than $QPM$ to the recent lQCD data performed including dynamical fermions. Finally, in a 1+1D expanding system, we evaluate the $R_{AA}(p_T)$ in the $QPM$ and $QPM_p$, finding a significant reduction at low momenta for $QPM_p$ which could lead in a realistic scenario to a better agreement to experimental data.
2205.02396
Wei Kou
Xiaopeng Wang, Wei Kou, Gang Xie, Yaping Xie, Xurong Chen
Exclusive vector meson productions with the analytical solution of Balitsky-Kovchegov Equation
10 pages,8 figures,1 table. Add some references. The paper is to be published in Chinese Physics C
null
10.1088/1674-1137/ac6daa
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
Exclusive vector meson production is an excellent probe for describing the structure of proton. In this paper, based on dipole model, the differential cross sections, total cross sections and the ratios of the longitudinal to transverse cross sections of $J/\psi$ and $\rho^0$ productions are calculated with the analytical solution of Balitsky-Kovchegov (BK) equation. In addition, we also consider the influences of two meson wave function models on the results. Our predictions, which are little sensitive to meson wave functions, agree with the experimental data. The analytical solution of BK equation is reliable for description of exclusive vector meson production in a certain range of $Q^2$.
[ { "created": "Thu, 5 May 2022 02:04:02 GMT", "version": "v1" }, { "created": "Fri, 6 May 2022 14:29:06 GMT", "version": "v2" } ]
2022-09-07
[ [ "Wang", "Xiaopeng", "" ], [ "Kou", "Wei", "" ], [ "Xie", "Gang", "" ], [ "Xie", "Yaping", "" ], [ "Chen", "Xurong", "" ] ]
Exclusive vector meson production is an excellent probe for describing the structure of proton. In this paper, based on dipole model, the differential cross sections, total cross sections and the ratios of the longitudinal to transverse cross sections of $J/\psi$ and $\rho^0$ productions are calculated with the analytical solution of Balitsky-Kovchegov (BK) equation. In addition, we also consider the influences of two meson wave function models on the results. Our predictions, which are little sensitive to meson wave functions, agree with the experimental data. The analytical solution of BK equation is reliable for description of exclusive vector meson production in a certain range of $Q^2$.
1311.6113
James Currie
James Currie
Colourful antenna subtraction for gluon scattering
9 pages, 2 figures, proceedings for the 11th International Symposium on Radiative Corrections (Applications of Quantum Field Theory to Phenomenology) (RADCOR 2013)
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this talk I discuss the application and generalization of the antenna subtraction method to processes involving incoherent interferences of partial amplitudes, which are generically present for the sub-leading colour contributions to processes involving more than five partons. The approach makes use of the known infrared (IR) singularity structure of one- and two-loop matrix elements to guide the construction of the subtraction terms. A set of integrated dipoles are defined which can be used to express the poles of one- and two-loop matrix elements in terms of integrated antennae. The unintegrated counterparts of these subtraction terms are then inferred to construct the double real and real-virtual subtraction terms. The method has been tested by computing the NNLO sub-leading colour contribution dijet production via gluon scattering. The double real and real virtual matrix elements for this process can be written purely in terms of incoherent interferences and so the successful removal of all singularities and divergences demonstrates the ability of the antenna subtraction method to handle general sub-leading colour contributions
[ { "created": "Sun, 24 Nov 2013 12:25:18 GMT", "version": "v1" } ]
2013-11-26
[ [ "Currie", "James", "" ] ]
In this talk I discuss the application and generalization of the antenna subtraction method to processes involving incoherent interferences of partial amplitudes, which are generically present for the sub-leading colour contributions to processes involving more than five partons. The approach makes use of the known infrared (IR) singularity structure of one- and two-loop matrix elements to guide the construction of the subtraction terms. A set of integrated dipoles are defined which can be used to express the poles of one- and two-loop matrix elements in terms of integrated antennae. The unintegrated counterparts of these subtraction terms are then inferred to construct the double real and real-virtual subtraction terms. The method has been tested by computing the NNLO sub-leading colour contribution dijet production via gluon scattering. The double real and real virtual matrix elements for this process can be written purely in terms of incoherent interferences and so the successful removal of all singularities and divergences demonstrates the ability of the antenna subtraction method to handle general sub-leading colour contributions
1908.11333
Nikolaos Kidonakis
Nikolaos Kidonakis
Three-loop soft anomalous dimensions for top-quark production
8 pages, 2 figures; presented at the European Physical Society Conference on High Energy Physics (EPS-HEP2019), Ghent, Belgium, 10-17 July 2019
PoS (EPS-HEP2019) 660
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
I present results through three loops for soft anomalous dimensions that control soft-gluon emission in processes involving the top quark. In particular I present results for channels in single-top production and top-pair production as well as for processes with new physics, including $tZ$, $tZ'$, $t \gamma$, and $tH^-$ production. These calculations are ingredients to resummations at N$^3$LL accuracy and to derivations of N$^3$LO soft-gluon corrections.
[ { "created": "Thu, 29 Aug 2019 16:30:08 GMT", "version": "v1" } ]
2023-02-21
[ [ "Kidonakis", "Nikolaos", "" ] ]
I present results through three loops for soft anomalous dimensions that control soft-gluon emission in processes involving the top quark. In particular I present results for channels in single-top production and top-pair production as well as for processes with new physics, including $tZ$, $tZ'$, $t \gamma$, and $tH^-$ production. These calculations are ingredients to resummations at N$^3$LL accuracy and to derivations of N$^3$LO soft-gluon corrections.
1406.5539
Stefano Forte
Emanuele R.Nocera, Richard D.Ball, Stefano Forte, Giovanni Ridolfi and Juan Rojo (The NNPDF Collaboration)
A first unbiased global determination of polarized PDFs and their uncertainties
36 pages, 16 figures. Final version to be published in Nucl. Phys. B. Small textual improvements and minor typos corrected
null
10.1016/j.nuclphysb.2014.08.008
CERN-PH-TH-2014-106, IFUN-1028-FT,Edinburgh-14/11, OUTP-14-06P
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a first global determination of spin-dependent parton distribution functions (PDFs) and their uncertainties using the NNPDF methodology: NNPDFpol1.1. Longitudinally polarized deep-inelastic scattering data, already used for the previous NNPDFpol1.0 PDF set, are supplemented with the most recent polarized hadron collider data for inclusive jet and $W$ boson production from the STAR and PHENIX experiments at RHIC, and with open-charm production data from the COMPASS experiment, thereby allowing for a separate determination of the polarized quark and anti-quark PDFs, and an improved determination of the medium- and large-$x$ polarized gluon PDF. We study the phenomenological implications of the NNPDFpol1.1 set, and we provide predictions for the longitudinal double-spin asymmetry for semi-inclusive pion production at RHIC.
[ { "created": "Fri, 20 Jun 2014 21:07:39 GMT", "version": "v1" }, { "created": "Mon, 1 Sep 2014 17:48:38 GMT", "version": "v2" } ]
2015-06-22
[ [ "Nocera", "Emanuele R.", "", "The NNPDF Collaboration" ], [ "Ball", "Richard D.", "", "The NNPDF Collaboration" ], [ "Forte", "Stefano", "", "The NNPDF Collaboration" ], [ "Ridolfi", "Giovanni", "", "The NNPDF Collaboration" ], [ ...
We present a first global determination of spin-dependent parton distribution functions (PDFs) and their uncertainties using the NNPDF methodology: NNPDFpol1.1. Longitudinally polarized deep-inelastic scattering data, already used for the previous NNPDFpol1.0 PDF set, are supplemented with the most recent polarized hadron collider data for inclusive jet and $W$ boson production from the STAR and PHENIX experiments at RHIC, and with open-charm production data from the COMPASS experiment, thereby allowing for a separate determination of the polarized quark and anti-quark PDFs, and an improved determination of the medium- and large-$x$ polarized gluon PDF. We study the phenomenological implications of the NNPDFpol1.1 set, and we provide predictions for the longitudinal double-spin asymmetry for semi-inclusive pion production at RHIC.
hep-ph/0506287
V. J. Kolhinen
V.J. Kolhinen
Global Analyses of Nuclear PDFs
4 pages, 2 eps-figure. Uses aipproc class. Talk given at DIS 2005, Madison, USA, April 27-May 1, 2005
null
10.1063/1.2122034
null
hep-ph
null
A brief overview of the global DGLAP analyses of the nuclear parton distribution functions is given. Although all the current global nPDF sets describe $R_{F_2}^A(x,Q^2)$ well in the large-$x$ region where the data exist, variations between their parton distributions can be substantial.
[ { "created": "Tue, 28 Jun 2005 12:10:16 GMT", "version": "v1" } ]
2015-06-25
[ [ "Kolhinen", "V. J.", "" ] ]
A brief overview of the global DGLAP analyses of the nuclear parton distribution functions is given. Although all the current global nPDF sets describe $R_{F_2}^A(x,Q^2)$ well in the large-$x$ region where the data exist, variations between their parton distributions can be substantial.
2104.02328
Raghunath Sahoo
Aditya Nath Mishra, Dushmanta Sahu, and Raghunath Sahoo
Jet Transport Coefficient at the Large Hadron Collider Energies in a Color String Percolation Approach
Same as the published version
Physics 4, 315(2022)
10.3390/physics4010022
null
hep-ph hep-ex hep-th nucl-ex nucl-th
http://creativecommons.org/licenses/by-sa/4.0/
Within the color string percolation model (CSPM), jet transport coefficient, $\hat{q}$, is calculated for various multiplicity classes in proton-proton and centrality classes in nucleus-nucleus collisions at the Large Hadron Collider energies for a better understanding of the matter formed in ultra-relativistic collisions. $\hat{q}$ is studied as a function of final state charged particle multiplicity (pseudorapiditydensity at midrapidity), initial state percolation temperature and energy density. The CSPM results are then compared with different theoretical calculations from the JET Collaboration those incorporate particle energy loss in the medium.
[ { "created": "Tue, 6 Apr 2021 07:18:51 GMT", "version": "v1" }, { "created": "Thu, 17 Mar 2022 09:42:27 GMT", "version": "v2" } ]
2022-03-18
[ [ "Mishra", "Aditya Nath", "" ], [ "Sahu", "Dushmanta", "" ], [ "Sahoo", "Raghunath", "" ] ]
Within the color string percolation model (CSPM), jet transport coefficient, $\hat{q}$, is calculated for various multiplicity classes in proton-proton and centrality classes in nucleus-nucleus collisions at the Large Hadron Collider energies for a better understanding of the matter formed in ultra-relativistic collisions. $\hat{q}$ is studied as a function of final state charged particle multiplicity (pseudorapiditydensity at midrapidity), initial state percolation temperature and energy density. The CSPM results are then compared with different theoretical calculations from the JET Collaboration those incorporate particle energy loss in the medium.
0803.1967
Ara Ioannisian Dr.
A. N. Ioannisian, A. Yu. Smirnov
Describing neutrino oscillations in matter with Magnus expansion
Discussions expanded, two figures and references added, the version will appear in Nucl. Phys. B
Nucl.Phys.B816:94-116,2009
10.1016/j.nuclphysb.2009.02.028
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present new formalism for description of the neutrino oscillations in matter with varying density. The formalism is based on the Magnus expansion and has a virtue that the unitarity of the S-matrix is maintained in each order of perturbation theory. We show that the Magnus expansion provides better convergence of series: the restoration of unitarity leads to smaller deviations from the exact results especially in the regions of large transition probabilities. Various expansions are obtained depending on a basis of neutrino states and a way one splits the Hamiltonian into the self-commuting and non-commuting parts. In particular, we develop the Magnus expansion for the adiabatic perturbation theory which gives the best approximation. We apply the formalism to the neutrino oscillations in matter of the Earth and show that for the solar oscillation parameters the second order Magnus adiabatic expansion has better than 1% accuracy for all energies and trajectories. For the atmospheric $\Delta m^2$ and small 1-3 mixing the approximation works well ($< 3 %$ accuracy for $\sin^2 \theta_{13} = 0.01$) outside the resonance region (2.7 - 8) GeV.
[ { "created": "Thu, 13 Mar 2008 13:45:08 GMT", "version": "v1" }, { "created": "Thu, 26 Feb 2009 18:13:36 GMT", "version": "v2" } ]
2010-05-12
[ [ "Ioannisian", "A. N.", "" ], [ "Smirnov", "A. Yu.", "" ] ]
We present new formalism for description of the neutrino oscillations in matter with varying density. The formalism is based on the Magnus expansion and has a virtue that the unitarity of the S-matrix is maintained in each order of perturbation theory. We show that the Magnus expansion provides better convergence of series: the restoration of unitarity leads to smaller deviations from the exact results especially in the regions of large transition probabilities. Various expansions are obtained depending on a basis of neutrino states and a way one splits the Hamiltonian into the self-commuting and non-commuting parts. In particular, we develop the Magnus expansion for the adiabatic perturbation theory which gives the best approximation. We apply the formalism to the neutrino oscillations in matter of the Earth and show that for the solar oscillation parameters the second order Magnus adiabatic expansion has better than 1% accuracy for all energies and trajectories. For the atmospheric $\Delta m^2$ and small 1-3 mixing the approximation works well ($< 3 %$ accuracy for $\sin^2 \theta_{13} = 0.01$) outside the resonance region (2.7 - 8) GeV.
2404.03674
Jose L. Goity
Jose L. Goity and Christian Weiss
Target normal single-spin asymmetry in inclusive electron-nucleon scattering in the 1/Nc expansion
13 pages, 5 figures
null
null
JLAB-THY-24-3990
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The target normal single-spin asymmetry in electron nucleon scattering is studied in the framework of the 1/Nc expansion of QCD, which allows for a rigorous description in the energy range that includes the Delta resonance and below the second baryon resonance region. The asymmetry is driven by the absorptive part of the two-photon exchange component of the scattering amplitude, being therefore the most unambiguous two-photon exchange effect. Such amplitude is shown to be described up to the next to leading order in the 1/Nc expansion only in terms of the charge and magnetic form factors of the nucleons, consequence of the approximate $SU(4)$ spin flavor symmetry valid in the large Nc limit for baryons. A discussion is provided of the 1/Nc expansion framework along with the results for the asymmetries in elastic, inelastic, and inclusive electron-nucleon scattering.
[ { "created": "Tue, 26 Mar 2024 16:12:30 GMT", "version": "v1" } ]
2024-04-08
[ [ "Goity", "Jose L.", "" ], [ "Weiss", "Christian", "" ] ]
The target normal single-spin asymmetry in electron nucleon scattering is studied in the framework of the 1/Nc expansion of QCD, which allows for a rigorous description in the energy range that includes the Delta resonance and below the second baryon resonance region. The asymmetry is driven by the absorptive part of the two-photon exchange component of the scattering amplitude, being therefore the most unambiguous two-photon exchange effect. Such amplitude is shown to be described up to the next to leading order in the 1/Nc expansion only in terms of the charge and magnetic form factors of the nucleons, consequence of the approximate $SU(4)$ spin flavor symmetry valid in the large Nc limit for baryons. A discussion is provided of the 1/Nc expansion framework along with the results for the asymmetries in elastic, inelastic, and inclusive electron-nucleon scattering.
1102.4160
P C Vinodkumar
Ajay Majethiya, Kaushal Thakkar and P. C. Vinodkumar
Spectroscopy and decay properties of $\Sigma_{b}, \Lambda_{b}$ baryons in quark-diquark model
null
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Properties of single beauty baryons ($\Sigma_{b},\Lambda_{b}$) are studied based on the quark-diquark structure. The confinement potential is assumed as two body colour coulomb plus power potential with exponent $\nu$. We find a strong correlation between the choice of the heavy quark mass parameter ($m_{b}$), strong coupling constant ($\alpha_{s}$) and the potential exponent ($\nu$) for getting the experimental mass spilt of $m_{\Sigma^{*}_{b}}- m_{\Sigma_{b}}=21.2\pm2.0 $ MeV. The resultant spectroscopic parameters are used for computing magnetic moments, the electromagnetic radiative decay, strong hadronic decay and semileptonic decay widths of $\Sigma_{b}, \Lambda_{b}$ systems. Our predictions on the radiative decay width correspond to $\Sigma^{*0}_{b}\rightarrow\Lambda_{b}\gamma$ are in agreement with the QCD sum rule prediction. The present results on the semileptonic decay widths of $\Lambda_{b}\rightarrow \Lambda_{c}l\nu_{l}$ (2.50-4.73) $ *10^{10} s^{-1}$ are in agreement with the experimental value of $3.59^{+1.234}_{-0.936} *10^{10} s^{-1}$ reported by (PDG 2010).
[ { "created": "Mon, 21 Feb 2011 08:30:58 GMT", "version": "v1" } ]
2011-02-22
[ [ "Majethiya", "Ajay", "" ], [ "Thakkar", "Kaushal", "" ], [ "Vinodkumar", "P. C.", "" ] ]
Properties of single beauty baryons ($\Sigma_{b},\Lambda_{b}$) are studied based on the quark-diquark structure. The confinement potential is assumed as two body colour coulomb plus power potential with exponent $\nu$. We find a strong correlation between the choice of the heavy quark mass parameter ($m_{b}$), strong coupling constant ($\alpha_{s}$) and the potential exponent ($\nu$) for getting the experimental mass spilt of $m_{\Sigma^{*}_{b}}- m_{\Sigma_{b}}=21.2\pm2.0 $ MeV. The resultant spectroscopic parameters are used for computing magnetic moments, the electromagnetic radiative decay, strong hadronic decay and semileptonic decay widths of $\Sigma_{b}, \Lambda_{b}$ systems. Our predictions on the radiative decay width correspond to $\Sigma^{*0}_{b}\rightarrow\Lambda_{b}\gamma$ are in agreement with the QCD sum rule prediction. The present results on the semileptonic decay widths of $\Lambda_{b}\rightarrow \Lambda_{c}l\nu_{l}$ (2.50-4.73) $ *10^{10} s^{-1}$ are in agreement with the experimental value of $3.59^{+1.234}_{-0.936} *10^{10} s^{-1}$ reported by (PDG 2010).
hep-ph/9607216
D. I. Melikhov
D. Melikhov
Form factors of meson decays in constituent quark model
Contributed to 3rd German-Russian Workshop 'Heavy Quark Physics', 20-22 May, 1996, revtex, 4 pages
null
null
null
hep-ph
null
Meson decays are considered within the constituent quark model, making use of the dispersion formulation of the model: Starting with spacelike momentum transfers $q$, meson transition form factors are expressed as relativistic invariant double spectral representations over the invariant masses of the initial and final $Q\bar Q$ pairs. The form factors at timelike momentum transfers are obtained by performing the analytical continuation in $q^2$. As a result, the form factors both in the scattering and decay regions are expressed through the light--cone wave functions of the initial and final hadrons. The constituent quark transition form factor is briefly discussed.
[ { "created": "Tue, 2 Jul 1996 10:02:35 GMT", "version": "v1" } ]
2007-05-23
[ [ "Melikhov", "D.", "" ] ]
Meson decays are considered within the constituent quark model, making use of the dispersion formulation of the model: Starting with spacelike momentum transfers $q$, meson transition form factors are expressed as relativistic invariant double spectral representations over the invariant masses of the initial and final $Q\bar Q$ pairs. The form factors at timelike momentum transfers are obtained by performing the analytical continuation in $q^2$. As a result, the form factors both in the scattering and decay regions are expressed through the light--cone wave functions of the initial and final hadrons. The constituent quark transition form factor is briefly discussed.
hep-ph/0504146
Eugene Levin
M. Kozlov and E. Levin
Solution to the Balitsky-Kovchegov equation in the saturation domain
19 pages, 3 figures
Nucl.Phys. A764 (2006) 498-514
10.1016/j.nuclphysa.2005.09.018
TAUP 2803/2004
hep-ph
null
The solution to the Balitsky-Kovchegov equation is found in the deep saturation domain. The controversy between different approaches regarding the asymptotic behaviour of the scattering amplitude is solved. It is shown that the dipole amplitude behaves as $ 1 - \exp (- z + \ln z)$ with $ z = \ln (r^2 Q^2_s)$ ($ r$ -size of the dipole, $Q_s$ is the saturation scale) in the deep saturation region. This solution is developed from the scaling solution to the homogeneous Balitsky-Kovchegov equation. The dangers associated with making simplifications in the BFKL kernel, to investigate the asymptotic behaviour of the scattering amplitude, is pointed out . In particular, the fact that the Balitsky-Kovchegov equation belongs to the Fisher-Kolmogorov-Petrovsky-Piscounov -type of equation, needs further careful investigation.
[ { "created": "Mon, 18 Apr 2005 07:48:33 GMT", "version": "v1" } ]
2010-04-05
[ [ "Kozlov", "M.", "" ], [ "Levin", "E.", "" ] ]
The solution to the Balitsky-Kovchegov equation is found in the deep saturation domain. The controversy between different approaches regarding the asymptotic behaviour of the scattering amplitude is solved. It is shown that the dipole amplitude behaves as $ 1 - \exp (- z + \ln z)$ with $ z = \ln (r^2 Q^2_s)$ ($ r$ -size of the dipole, $Q_s$ is the saturation scale) in the deep saturation region. This solution is developed from the scaling solution to the homogeneous Balitsky-Kovchegov equation. The dangers associated with making simplifications in the BFKL kernel, to investigate the asymptotic behaviour of the scattering amplitude, is pointed out . In particular, the fact that the Balitsky-Kovchegov equation belongs to the Fisher-Kolmogorov-Petrovsky-Piscounov -type of equation, needs further careful investigation.
hep-ph/0201151
Xing ZhiZhong
Zhi-zhong Xing
Texture Zeros and Majorana Phases of the Neutrino Mass Matrix
LaTex 11 pages. Slight changes. Phys. Lett. B (in printing)
Phys.Lett. B530 (2002) 159-166
10.1016/S0370-2693(02)01354-0
BIHEP-TH-2002-5
hep-ph
null
We present the generic formulas to calculate the ratios of neutrino masses and the Majorana phases of CP violation from the neutrino mass matrix with two independent vanishing entries in the flavor basis where the charged lepton mass matrix is diagonal. An order-of-magnitude illustration is given for seven experimentally acceptable textures of the neutrino mass matrix, and some analytical approximations are made for their phenomenological consequences at low energy scales.
[ { "created": "Thu, 17 Jan 2002 01:34:07 GMT", "version": "v1" }, { "created": "Fri, 22 Feb 2002 02:04:16 GMT", "version": "v2" } ]
2009-11-07
[ [ "Xing", "Zhi-zhong", "" ] ]
We present the generic formulas to calculate the ratios of neutrino masses and the Majorana phases of CP violation from the neutrino mass matrix with two independent vanishing entries in the flavor basis where the charged lepton mass matrix is diagonal. An order-of-magnitude illustration is given for seven experimentally acceptable textures of the neutrino mass matrix, and some analytical approximations are made for their phenomenological consequences at low energy scales.
1304.6868
Krishna Kingkar Pathak
Krishna Kingkar Pathak and D K Choudhury
CKM matrix element Vcb in a QCD Potential model
9 pages, 1 figure
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the slope $\rho^{2}$ and curvature $C$ of Isgur Wise function for the heavy-light mesons in general with particular emphasis on $B$ meson in a QCD Potential model. The IW function is then used to compute the partial decay width and branching ratio for the semileptonic decay of $\left(B^{0}\rightarrow{D,D^{*}l\nu}\right)$. The computed value of the CKM element $|V_{cb}|=0.040$ is found to be in agreement with the available data.
[ { "created": "Thu, 25 Apr 2013 10:44:23 GMT", "version": "v1" } ]
2013-04-26
[ [ "Pathak", "Krishna Kingkar", "" ], [ "Choudhury", "D K", "" ] ]
We study the slope $\rho^{2}$ and curvature $C$ of Isgur Wise function for the heavy-light mesons in general with particular emphasis on $B$ meson in a QCD Potential model. The IW function is then used to compute the partial decay width and branching ratio for the semileptonic decay of $\left(B^{0}\rightarrow{D,D^{*}l\nu}\right)$. The computed value of the CKM element $|V_{cb}|=0.040$ is found to be in agreement with the available data.
0803.1151
Alan R. White
Alan R. White
The "Crisis in Fundamental Physics" - Will the LHC Pomeron End it?
Presented at the 5th Manchester Forward Physics Workshop, Dec. 2007
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
SU(5) gauge theory with massless left-handed fermions in the representation 5+15+40+45* (QUD) may have a bound-state S-Matrix that, uniquely, contains the asymptotically unitary Critical Pomeron and which might also reproduce the full Standard Model. If so, QUD would provide an underlying unification for the Standard Model in which very similar massless fermion anomaly dynamics is responsible for the physics of the strong and electroweak interactions and all particle masses are generated dynamically. The color sextet quark sector, responsible for both electroweak symmetry-breaking and dark matter in QUD, is predicted to produce large cross-section effects at the LHC, with the pomeron as a vital diagnostic - via TOTEM/CMS and FP420. In this talk, the multi-regge construction of high-energy QUD amplitudes is outlined as is, briefly, the LHC pomeron physics. Surrounding motivational issues (particularly outstanding QCD problems) and consequences are also discussed. The S-Matrix anomaly physics is conceptually and philosophically radical with respect to the current theory paradigm. As a consequence, QUD could provide a welcome way out of the current ``Crisis in Fundamental Physics'' with, potentially, it's novel physical applicability resolving a variety of Standard Model and, perhaps also, cosmology problems - it has zero vacuum energy.
[ { "created": "Fri, 7 Mar 2008 18:58:38 GMT", "version": "v1" } ]
2008-03-10
[ [ "White", "Alan R.", "" ] ]
SU(5) gauge theory with massless left-handed fermions in the representation 5+15+40+45* (QUD) may have a bound-state S-Matrix that, uniquely, contains the asymptotically unitary Critical Pomeron and which might also reproduce the full Standard Model. If so, QUD would provide an underlying unification for the Standard Model in which very similar massless fermion anomaly dynamics is responsible for the physics of the strong and electroweak interactions and all particle masses are generated dynamically. The color sextet quark sector, responsible for both electroweak symmetry-breaking and dark matter in QUD, is predicted to produce large cross-section effects at the LHC, with the pomeron as a vital diagnostic - via TOTEM/CMS and FP420. In this talk, the multi-regge construction of high-energy QUD amplitudes is outlined as is, briefly, the LHC pomeron physics. Surrounding motivational issues (particularly outstanding QCD problems) and consequences are also discussed. The S-Matrix anomaly physics is conceptually and philosophically radical with respect to the current theory paradigm. As a consequence, QUD could provide a welcome way out of the current ``Crisis in Fundamental Physics'' with, potentially, it's novel physical applicability resolving a variety of Standard Model and, perhaps also, cosmology problems - it has zero vacuum energy.
hep-ph/0307133
Matthias Lutz F. M.
E.E. Kolomeitsev and M.F.M. Lutz
On heavy-light meson resonances and chiral symmetry
revised manuscript: improved discussion and minor corrections
Phys.Lett.B582:39-48,2004
10.1016/j.physletb.2003.10.118
GSI-Preprint-2003-20
hep-ph nucl-th
null
We study heavy-light meson resonances with quantum numbers J^P=0^+ and J^P=1^+ in terms of the non-linear chiral SU(3) Lagrangian. At leading order a parameter-free prediction is obtained for the scattering of Goldstone bosons off heavy-light pseudo-scalar and vector mesons once we insist on approximate crossing symmetry of the unitarized scattering amplitude. The recently announced narrow open charm states observed by the BABAR and CLEO collaborations are reproduced. We suggest the existence of states that form an anti-triplet and a sextet representation of the SU(3) group. In particular, so far unobserved narrow isospin-singlet states with negative strangeness (I,S)=(0,-1) are predicted at 2361 MeV J^P=0^+ and 2501 MeV (J^P=1^+). Similarly, open bottom states are found at 5719 MeV (J^P=0^+) and 5622 MeV (J^P=1^+). Additional narrow states of mass 5580 MeV (J^P=0^+) and 5650 MeV (J^P=1^+) with widths of about 50 MeV are obtained in the (I,S)=(1,1) sector. For the anti-triplet states our results differ most significantly from predictions that are based on a linear realization of the chiral SU(3) symmetry in the open bottom sector. Strongly bound 0^+-and 1^+-states with (I,S)=(0,1) at 5507 MeV and 5553 MeV are predicted.
[ { "created": "Wed, 9 Jul 2003 17:40:41 GMT", "version": "v1" }, { "created": "Wed, 13 Aug 2003 15:42:48 GMT", "version": "v2" } ]
2008-11-26
[ [ "Kolomeitsev", "E. E.", "" ], [ "Lutz", "M. F. M.", "" ] ]
We study heavy-light meson resonances with quantum numbers J^P=0^+ and J^P=1^+ in terms of the non-linear chiral SU(3) Lagrangian. At leading order a parameter-free prediction is obtained for the scattering of Goldstone bosons off heavy-light pseudo-scalar and vector mesons once we insist on approximate crossing symmetry of the unitarized scattering amplitude. The recently announced narrow open charm states observed by the BABAR and CLEO collaborations are reproduced. We suggest the existence of states that form an anti-triplet and a sextet representation of the SU(3) group. In particular, so far unobserved narrow isospin-singlet states with negative strangeness (I,S)=(0,-1) are predicted at 2361 MeV J^P=0^+ and 2501 MeV (J^P=1^+). Similarly, open bottom states are found at 5719 MeV (J^P=0^+) and 5622 MeV (J^P=1^+). Additional narrow states of mass 5580 MeV (J^P=0^+) and 5650 MeV (J^P=1^+) with widths of about 50 MeV are obtained in the (I,S)=(1,1) sector. For the anti-triplet states our results differ most significantly from predictions that are based on a linear realization of the chiral SU(3) symmetry in the open bottom sector. Strongly bound 0^+-and 1^+-states with (I,S)=(0,1) at 5507 MeV and 5553 MeV are predicted.
1610.06588
Cristian Bosch
Gabriela Barenboim, Cristian Bosch
A composite tale of two right-handed neutrinos
24 pages, 5 figures
Phys. Rev. D 94, 116019 (2016)
10.1103/PhysRevD.94.116019
FTUV-10-29, IFIC/16-73
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this work, we develop a model for Higgs-like composites based on two generations of right handed neutrinos which condense. We analyze the Spontaneous Symmetry Breaking of the theory with two explicit breakings, setting the different scales of the model and obtaining massive bosons as a result. Finally, we calculate the gravitational wave imprint left by the phase transition associated to the symmetry breaking of a generic potential dictated by the symmetries of the composites.
[ { "created": "Thu, 20 Oct 2016 20:01:29 GMT", "version": "v1" } ]
2017-01-04
[ [ "Barenboim", "Gabriela", "" ], [ "Bosch", "Cristian", "" ] ]
In this work, we develop a model for Higgs-like composites based on two generations of right handed neutrinos which condense. We analyze the Spontaneous Symmetry Breaking of the theory with two explicit breakings, setting the different scales of the model and obtaining massive bosons as a result. Finally, we calculate the gravitational wave imprint left by the phase transition associated to the symmetry breaking of a generic potential dictated by the symmetries of the composites.
1608.08922
Igor Ivanov
Alfredo Aranda, Igor P. Ivanov, Enrique Jim\'enez
When the C in CP does not matter: anatomy of order-4 CP eigenstates and their Yukawa interactions
18 pages; v2: discussion expanded, references added; v3: more discussions and explanations provided, matches the published version
Phys. Rev. D 95, 055010 (2017)
10.1103/PhysRevD.95.055010
CFTP/16-017
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We explore the origin and Yukawa interactions of the scalars with peculiar CP-properties which were recently found in a multi-Higgs model based on an order-4 CP symmetry. We relate the existence of such scalars to the enhanced freedom of defining CP, even beyond the well-known generalized CP symmetries, which arises in models with several zero-charge scalar fields. We also show that despite possessing exotic CP quantum numbers, these scalars do not have to be inert: they can have CP-conserving Yukawa interactions provided the CP acts on fermions by also mixing generations. This paper focuses on formal aspects---exposed in a pedagogical manner---and includes a brief discussion of possible phenomenological consequences.
[ { "created": "Wed, 31 Aug 2016 16:07:22 GMT", "version": "v1" }, { "created": "Sat, 24 Sep 2016 20:55:21 GMT", "version": "v2" }, { "created": "Mon, 13 Mar 2017 17:35:06 GMT", "version": "v3" } ]
2017-03-15
[ [ "Aranda", "Alfredo", "" ], [ "Ivanov", "Igor P.", "" ], [ "Jiménez", "Enrique", "" ] ]
We explore the origin and Yukawa interactions of the scalars with peculiar CP-properties which were recently found in a multi-Higgs model based on an order-4 CP symmetry. We relate the existence of such scalars to the enhanced freedom of defining CP, even beyond the well-known generalized CP symmetries, which arises in models with several zero-charge scalar fields. We also show that despite possessing exotic CP quantum numbers, these scalars do not have to be inert: they can have CP-conserving Yukawa interactions provided the CP acts on fermions by also mixing generations. This paper focuses on formal aspects---exposed in a pedagogical manner---and includes a brief discussion of possible phenomenological consequences.
1411.3727
Eric Kuflik
Yonit Hochberg, Eric Kuflik, Hitoshi Murayama, Tomer Volansky, and Jay G. Wacker
The SIMPlest Miracle
8 pages, 2 figures; v2: published in PRL under the title "Model for thermal relic dark matter of strongly interacting massive particles"
Phys. Rev. Lett. 115, 021301 (2015)
10.1103/PhysRevLett.115.021301
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It has recently been proposed that dark matter could be a thermal relic of 3-to-2 scatterings in a strongly coupled hidden sector. We present explicit classes of strongly coupled gauge theories that admit this behavior. These are QCD-like theories of dynamical chiral symmetry breaking, where the pions play the role of dark matter. The number-changing 3-to-2 process, which sets the dark matter relic abundance, arises from the Wess-Zumino-Witten term. The theories give an explicit relationship between the 3-to-2 annihilation rate and the 2-to-2 self-scattering rate, which alters predictions for structure formation. This is a simple calculable realization of the strongly-interacting-massive-particle (SIMP) mechanism.
[ { "created": "Thu, 13 Nov 2014 21:00:07 GMT", "version": "v1" }, { "created": "Sun, 26 Jul 2015 21:48:44 GMT", "version": "v2" } ]
2015-07-28
[ [ "Hochberg", "Yonit", "" ], [ "Kuflik", "Eric", "" ], [ "Murayama", "Hitoshi", "" ], [ "Volansky", "Tomer", "" ], [ "Wacker", "Jay G.", "" ] ]
It has recently been proposed that dark matter could be a thermal relic of 3-to-2 scatterings in a strongly coupled hidden sector. We present explicit classes of strongly coupled gauge theories that admit this behavior. These are QCD-like theories of dynamical chiral symmetry breaking, where the pions play the role of dark matter. The number-changing 3-to-2 process, which sets the dark matter relic abundance, arises from the Wess-Zumino-Witten term. The theories give an explicit relationship between the 3-to-2 annihilation rate and the 2-to-2 self-scattering rate, which alters predictions for structure formation. This is a simple calculable realization of the strongly-interacting-massive-particle (SIMP) mechanism.
hep-ph/0608196
Piotr R\c{a}czka
Piotr A. Raczka
Towards more reliable perturbative QCD predictions at moderate energies
62 pages LaTeX, JHEP style, 19 figures
null
null
IFT-12-2006
hep-ph
null
The problem of improving the reliability of perturbative QCD predictions at moderate energies is considered. These predictions suffer from substantial renormalization scheme dependence, which is illustrated using as an example the QCD effective charge appearing in the static interquark potential and the QCD corrections to the Gross-Llewellyn-Smith sum rule in the deep inelastic neutrino-nucleon scattering. To reduce this scheme dependence, it is proposed to use a modified perturbation expansion, based on a modified couplant, which is perturbatively consistent with the conventional running coupling parameter, but is free from Landau singularity and has smaller renormalization scheme dependence. The modified couplant is obtained by integrating the renormalization group equation with an appropriately constructed nonpolynomial generator. The renormalization scheme dependence of the perturbative predictions in the modified expansion is discussed in detail, including the predictions selected by the Principle of Minimal Sensitivity. It is shown that the modified predictions are much more stable with respect to change of the renormalization scheme parameters than the predictions obtained in the conventional approach. It is also found that the modified predictions display somewhat weaker energy dependence than the predictions obtained with the conventional expansion, which may be interesting from the point of view of comparing the low energy and high energy determinations of the strong coupling parameter.
[ { "created": "Fri, 18 Aug 2006 00:46:44 GMT", "version": "v1" } ]
2007-05-23
[ [ "Raczka", "Piotr A.", "" ] ]
The problem of improving the reliability of perturbative QCD predictions at moderate energies is considered. These predictions suffer from substantial renormalization scheme dependence, which is illustrated using as an example the QCD effective charge appearing in the static interquark potential and the QCD corrections to the Gross-Llewellyn-Smith sum rule in the deep inelastic neutrino-nucleon scattering. To reduce this scheme dependence, it is proposed to use a modified perturbation expansion, based on a modified couplant, which is perturbatively consistent with the conventional running coupling parameter, but is free from Landau singularity and has smaller renormalization scheme dependence. The modified couplant is obtained by integrating the renormalization group equation with an appropriately constructed nonpolynomial generator. The renormalization scheme dependence of the perturbative predictions in the modified expansion is discussed in detail, including the predictions selected by the Principle of Minimal Sensitivity. It is shown that the modified predictions are much more stable with respect to change of the renormalization scheme parameters than the predictions obtained in the conventional approach. It is also found that the modified predictions display somewhat weaker energy dependence than the predictions obtained with the conventional expansion, which may be interesting from the point of view of comparing the low energy and high energy determinations of the strong coupling parameter.
hep-ph/0304168
Lance Dixon
Z. Bern, A. De Freitas, and L. Dixon
Two-Loop Helicity Amplitudes for Quark-Gluon Scattering in QCD and Gluino-Gluon Scattering in Supersymmetric Yang-Mills Theory
77 pages. v2: corrected errors in eqs. (3.7) and (3.8) for one-loop assembly; remaining results unaffected
JHEP 0306:028,2003
10.1088/1126-6708/2003/06/028
SLAC-PUB-9675, DESY 03-034, UCLA/02/TEP/2
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present the two-loop QCD helicity amplitudes for quark-gluon scattering, and for quark-antiquark annihilation into two gluons. These amplitudes are relevant for next-to-next-to-leading order corrections to (polarized) jet production at hadron colliders. We give the results in the `t Hooft-Veltman and four-dimensional helicity (FDH) variants of dimensional regularization. The transition rules for converting the amplitudes between the different variants are much more intricate than for the previously discussed case of gluon-gluon scattering. Summing our two-loop expressions over helicities and colors, and converting to conventional dimensional regularization, gives results in complete agreement with those of Anastasiou, Glover, Oleari and Tejeda-Yeomans. We describe the amplitudes for 2 to 2 scattering in pure N=1 supersymmetric Yang-Mills theory, obtained from the QCD amplitudes by modifying the color representation and multiplicities, and verify supersymmetry Ward identities in the FDH scheme.
[ { "created": "Wed, 16 Apr 2003 22:58:30 GMT", "version": "v1" }, { "created": "Mon, 27 Jan 2014 17:52:37 GMT", "version": "v2" } ]
2014-01-28
[ [ "Bern", "Z.", "" ], [ "De Freitas", "A.", "" ], [ "Dixon", "L.", "" ] ]
We present the two-loop QCD helicity amplitudes for quark-gluon scattering, and for quark-antiquark annihilation into two gluons. These amplitudes are relevant for next-to-next-to-leading order corrections to (polarized) jet production at hadron colliders. We give the results in the `t Hooft-Veltman and four-dimensional helicity (FDH) variants of dimensional regularization. The transition rules for converting the amplitudes between the different variants are much more intricate than for the previously discussed case of gluon-gluon scattering. Summing our two-loop expressions over helicities and colors, and converting to conventional dimensional regularization, gives results in complete agreement with those of Anastasiou, Glover, Oleari and Tejeda-Yeomans. We describe the amplitudes for 2 to 2 scattering in pure N=1 supersymmetric Yang-Mills theory, obtained from the QCD amplitudes by modifying the color representation and multiplicities, and verify supersymmetry Ward identities in the FDH scheme.
hep-ph/0410336
Kazunori Itakura
Kazunori Itakura
Color Glass Condensate in QCD at High Energy
4 pages, talk presented at ICHEP2004, Beijing, China, August 2004, minor modification
null
10.1142/9789812702227_0056
null
hep-ph
null
I give a brief review about the color glass condensate, which is the universal form of hadrons and nuclei at high energies.
[ { "created": "Mon, 25 Oct 2004 16:06:56 GMT", "version": "v1" }, { "created": "Thu, 28 Oct 2004 08:58:14 GMT", "version": "v2" } ]
2017-08-23
[ [ "Itakura", "Kazunori", "" ] ]
I give a brief review about the color glass condensate, which is the universal form of hadrons and nuclei at high energies.