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hep-ph/0412070
Yoshinori Cho
Yoshinori Cho, Kiyoshi Shiraishi
Finite density effects in Hosotani mechanism and a vacuum gauge ball
20 pages, 7 figures. RevTeX4
null
null
null
hep-ph astro-ph hep-th
null
We consider the finite density effects of the fermion with U(1) gauge symmetry in Hosotani mechanism. We construct a vacuum gauge ball, a new kind of non-topological soliton, and investigate their properties numerically. We find the relations between the physical quantities.
[ { "created": "Mon, 6 Dec 2004 04:11:11 GMT", "version": "v1" }, { "created": "Tue, 21 Dec 2004 03:41:45 GMT", "version": "v2" } ]
2007-05-23
[ [ "Cho", "Yoshinori", "" ], [ "Shiraishi", "Kiyoshi", "" ] ]
We consider the finite density effects of the fermion with U(1) gauge symmetry in Hosotani mechanism. We construct a vacuum gauge ball, a new kind of non-topological soliton, and investigate their properties numerically. We find the relations between the physical quantities.
1306.6089
Peter Graham
Dmitry Budker, Peter W. Graham, Micah Ledbetter, Surjeet Rajendran, Alex Sushkov
Cosmic Axion Spin Precession Experiment (CASPEr)
11 pages, 2 figures, 1 table. v2: Reordered sections and minor modifications to agree with published version
Phys. Rev. X 4, 021030 (2014)
10.1103/PhysRevX.4.021030
null
hep-ph astro-ph.CO cond-mat.other hep-ex quant-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose an experiment to search for QCD axion and axion-like-particle (ALP) dark matter. Nuclei that are interacting with the background axion dark matter acquire time-varying CP-odd nuclear moments such as an electric dipole moment. In analogy with nuclear magnetic resonance, these moments cause precession of nuclear spins in a material sample in the presence of an electric field. Precision magnetometry can be used to search for such precession. An initial phase of this experiment could cover many orders of magnitude in ALP parameter space beyond the current astrophysical and laboratory limits. And with established techniques, the proposed experimental scheme has sensitivity to QCD axion masses m_a < 10^-9 eV, corresponding to theoretically well-motivated axion decay constants f_a > 10^16 GeV. With further improvements, this experiment could ultimately cover the entire range of masses m_a < 10^-6 eV, complementary to cavity searches.
[ { "created": "Tue, 25 Jun 2013 21:06:15 GMT", "version": "v1" }, { "created": "Thu, 29 May 2014 17:00:31 GMT", "version": "v2" } ]
2014-05-30
[ [ "Budker", "Dmitry", "" ], [ "Graham", "Peter W.", "" ], [ "Ledbetter", "Micah", "" ], [ "Rajendran", "Surjeet", "" ], [ "Sushkov", "Alex", "" ] ]
We propose an experiment to search for QCD axion and axion-like-particle (ALP) dark matter. Nuclei that are interacting with the background axion dark matter acquire time-varying CP-odd nuclear moments such as an electric dipole moment. In analogy with nuclear magnetic resonance, these moments cause precession of nuclear spins in a material sample in the presence of an electric field. Precision magnetometry can be used to search for such precession. An initial phase of this experiment could cover many orders of magnitude in ALP parameter space beyond the current astrophysical and laboratory limits. And with established techniques, the proposed experimental scheme has sensitivity to QCD axion masses m_a < 10^-9 eV, corresponding to theoretically well-motivated axion decay constants f_a > 10^16 GeV. With further improvements, this experiment could ultimately cover the entire range of masses m_a < 10^-6 eV, complementary to cavity searches.
2311.00043
Sean Tulin
Safa Ben Othman, Armita Jalooli, Sean Tulin
Baryonic dark forces in electron-beam fixed-target experiments
28 pages, 12 figures; minor revisions, matches published version
null
null
null
hep-ph hep-ex
http://creativecommons.org/licenses/by-nc-nd/4.0/
New GeV-scale dark forces coupling predominantly to quarks offer novel signatures that can be produced directly and searched for at high-luminosity colliders. We compute the photon-proton and electron-proton cross sections for producing a GeV-scale gauge boson arising from a $U(1)_B$ gauge symmetry. Our calculation relies on vector meson dominance and a phenomenological model for diffractive scattering used for vector-meson photoproduction. The parameters of our phenomenological model are fixed by performing a Markov Chain Monte Carlo fit to existing exclusive photoproduction data for $\omega$ and $\phi$ mesons. Our approach can be generalized to other GeV-scale dark gauge forces.
[ { "created": "Tue, 31 Oct 2023 18:00:10 GMT", "version": "v1" }, { "created": "Fri, 19 Jan 2024 21:37:09 GMT", "version": "v2" } ]
2024-01-23
[ [ "Othman", "Safa Ben", "" ], [ "Jalooli", "Armita", "" ], [ "Tulin", "Sean", "" ] ]
New GeV-scale dark forces coupling predominantly to quarks offer novel signatures that can be produced directly and searched for at high-luminosity colliders. We compute the photon-proton and electron-proton cross sections for producing a GeV-scale gauge boson arising from a $U(1)_B$ gauge symmetry. Our calculation relies on vector meson dominance and a phenomenological model for diffractive scattering used for vector-meson photoproduction. The parameters of our phenomenological model are fixed by performing a Markov Chain Monte Carlo fit to existing exclusive photoproduction data for $\omega$ and $\phi$ mesons. Our approach can be generalized to other GeV-scale dark gauge forces.
hep-ph/9906433
K. Matsuda
K. Matsuda, H. Nishiura and T. Fukuyama
SO(10) GUT and Quark-Lepton Mass Matrices
32pp, REV TeX, 12 EPS Figures
Phys.Rev. D61 (2000) 053001
10.1103/PhysRevD.61.053001
null
hep-ph
null
The phenomenological model that all quark and lepton mass matrices have the same zero texture, namely their (1,1), (1,3) and (3,1) components are zeros, is discussed in the context of SO(10) Grand Unified Theories (GUTs). The mass matrices of type I for quarks are consistent with the experimental data in the quark sector. For the lepton sector, consistent fitting to the data of neutrino oscillation experiments force us to use the mass matrix for the charged leptons which is slightly deviated from type I. Given quark masses and charged lepton masses, the model includes 19 free parameters, whereas the SO(10) GUTs gives 16 constrained equations. Changing the remaining three parameters freely, we can fit all the entries of the CKM quark mixing matrix and the MNS lepton mixing matrix, and three neutrino masses consistently with the present experimental data.
[ { "created": "Sat, 19 Jun 1999 11:41:31 GMT", "version": "v1" }, { "created": "Fri, 29 Oct 1999 07:16:17 GMT", "version": "v2" } ]
2009-10-31
[ [ "Matsuda", "K.", "" ], [ "Nishiura", "H.", "" ], [ "Fukuyama", "T.", "" ] ]
The phenomenological model that all quark and lepton mass matrices have the same zero texture, namely their (1,1), (1,3) and (3,1) components are zeros, is discussed in the context of SO(10) Grand Unified Theories (GUTs). The mass matrices of type I for quarks are consistent with the experimental data in the quark sector. For the lepton sector, consistent fitting to the data of neutrino oscillation experiments force us to use the mass matrix for the charged leptons which is slightly deviated from type I. Given quark masses and charged lepton masses, the model includes 19 free parameters, whereas the SO(10) GUTs gives 16 constrained equations. Changing the remaining three parameters freely, we can fit all the entries of the CKM quark mixing matrix and the MNS lepton mixing matrix, and three neutrino masses consistently with the present experimental data.
0812.2397
Miguel Sanchis
Miguel-Angel Sanchis-Lozano
Prospects of searching for (un)particles from Hidden Sectors using rapidity correlations in multiparticle production at the LHC
36 pages, 6 figures. New references and a new section on Glasma physics have been added
Int.J.Mod.Phys.A24:4529-4572,2009
10.1142/S0217751X09045820
IFIC/08-61, FTUV-08-1212
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Most signatures of new physics have been studied on the transverse plane with respect to the beam direction at the LHC where background is much reduced. In this paper we propose the analysis of inclusive longitudinal (pseudo)rapidity correlations among final-state (charged) particles in order to search for (un)particles belonging to a Hidden Sector beyond the Standard Model, using a selected sample of p-p minimum bias events (applying appropriate off-line cuts on events based on, e.g., minijets, high-multiplicity, event shape variables, high-pT leptons and photons, etc) collected at the early running of the LHC. To this aim, we examine inclusive and semi-inclusive two-particle correlation functions, forward-backward correlations, and factorial moments of the multiplicity distribution, without resorting to any particular model but under very general (though simplifying) assumptions. Finally, motivated by some analysis techniques employed in the search for Quark-Gluon-Plasma in heavy-ion collisions, we investigate the impact of such intermediate (un)particle stuff on the (multi)fractality of parton cascades in p-p collisions, by means of a Levy stable law description and a Ginzburg-Landau model of phase transitions. Results from our preliminary study seem encouraging for possible dedicated analyses at the LHC and Tevatron experiments.
[ { "created": "Fri, 12 Dec 2008 18:24:43 GMT", "version": "v1" }, { "created": "Sat, 13 Dec 2008 17:15:58 GMT", "version": "v2" }, { "created": "Fri, 23 Jan 2009 17:13:09 GMT", "version": "v3" } ]
2010-04-30
[ [ "Sanchis-Lozano", "Miguel-Angel", "" ] ]
Most signatures of new physics have been studied on the transverse plane with respect to the beam direction at the LHC where background is much reduced. In this paper we propose the analysis of inclusive longitudinal (pseudo)rapidity correlations among final-state (charged) particles in order to search for (un)particles belonging to a Hidden Sector beyond the Standard Model, using a selected sample of p-p minimum bias events (applying appropriate off-line cuts on events based on, e.g., minijets, high-multiplicity, event shape variables, high-pT leptons and photons, etc) collected at the early running of the LHC. To this aim, we examine inclusive and semi-inclusive two-particle correlation functions, forward-backward correlations, and factorial moments of the multiplicity distribution, without resorting to any particular model but under very general (though simplifying) assumptions. Finally, motivated by some analysis techniques employed in the search for Quark-Gluon-Plasma in heavy-ion collisions, we investigate the impact of such intermediate (un)particle stuff on the (multi)fractality of parton cascades in p-p collisions, by means of a Levy stable law description and a Ginzburg-Landau model of phase transitions. Results from our preliminary study seem encouraging for possible dedicated analyses at the LHC and Tevatron experiments.
1607.01409
A. Tureanu
Kazuo Fujikawa and Anca Tureanu
Lorentz invariant CPT breaking in the Dirac equation
Talk given at the Memorial Meeting for Abdus Salam's 90th Birthday, Nanyang Technological University, Singapore, January 25-28, 2016 (to appear in the Proceedings)
null
10.1142/S0217751X17410147
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
If one modifies the Dirac equation in momentum space to $[\gamma^{\mu}p_{\mu}-m-\Delta m(\theta(p_{0})-\theta(-p_{0})) \theta(p_{\mu}^{2})]\psi(p)=0$, the symmetry of positive and negative energy eigenvalues is lifted by $m\pm \Delta m$ for a small $\Delta m$. The mass degeneracy of the particle and antiparticle is thus lifted in a Lorentz invariant manner since the combinations $\theta(\pm p_{0})\theta(p_{\mu}^{2})$ with step functions are manifestly Lorentz invariant. We explain an explicit construction of this CPT breaking term in coordinate space, which is Lorentz invariant but non-local at a distance scale of the Planck length. The application of this Lorentz invariant CPT breaking mechanism to the possible mass splitting of the neutrino and antineutrino in the Standard Model is briefly discussed.
[ { "created": "Tue, 5 Jul 2016 20:35:32 GMT", "version": "v1" } ]
2017-04-05
[ [ "Fujikawa", "Kazuo", "" ], [ "Tureanu", "Anca", "" ] ]
If one modifies the Dirac equation in momentum space to $[\gamma^{\mu}p_{\mu}-m-\Delta m(\theta(p_{0})-\theta(-p_{0})) \theta(p_{\mu}^{2})]\psi(p)=0$, the symmetry of positive and negative energy eigenvalues is lifted by $m\pm \Delta m$ for a small $\Delta m$. The mass degeneracy of the particle and antiparticle is thus lifted in a Lorentz invariant manner since the combinations $\theta(\pm p_{0})\theta(p_{\mu}^{2})$ with step functions are manifestly Lorentz invariant. We explain an explicit construction of this CPT breaking term in coordinate space, which is Lorentz invariant but non-local at a distance scale of the Planck length. The application of this Lorentz invariant CPT breaking mechanism to the possible mass splitting of the neutrino and antineutrino in the Standard Model is briefly discussed.
2310.05749
Renan Pereira
Renan C\^amara Pereira, Jo\~ao Moreira, Pedro Costa and Constan\c{c}a Provid\^encia
A new approach to the 3-momentum regularization of the in-medium one and two fermion line integrals with applications to cross sections in the Nambu--Jona-Lasinio model
65 pages, 25 figures
null
null
null
hep-ph nucl-th
http://creativecommons.org/licenses/by/4.0/
We propose the 3-momentum sphere intersection regularization applied to the one and two fermion line integrals at finite temperature and chemical potential. The quark-antiquark polarization function in this new regularization approach is equivalent to the usual 3-momentum regularization, when the absolute value of the external 3-momentum of the polarization is zero. Additionally, it respects the particle-antiparticle symmetry of meson states in the Nambu$-$Jona-Lasinio (NJL) model for all values of temperature and chemical potential. Without this symmetry, in-medium cross sections calculated in the 3-momentum regularized NJL model are not consistent. In order to demonstrate the difference between the usual 3-momentum regularization with the one proposed in this work, we study the quark-quark and quark-antiquark cross sections in both regularization schemes. To this end we use the standard $SU(3)$ NJL model, with four and six quark interactions. We observe major quantitative and qualitative differences when comparing quark-quark cross sections in both schemes. The quark-antiquark cross sections, on the other hand, are very similar in both regularizations, owning to the equivalence between the regularizations when the absolute value of the external 3-momentum is zero.
[ { "created": "Mon, 9 Oct 2023 14:23:47 GMT", "version": "v1" } ]
2023-10-10
[ [ "Pereira", "Renan Câmara", "" ], [ "Moreira", "João", "" ], [ "Costa", "Pedro", "" ], [ "Providência", "Constança", "" ] ]
We propose the 3-momentum sphere intersection regularization applied to the one and two fermion line integrals at finite temperature and chemical potential. The quark-antiquark polarization function in this new regularization approach is equivalent to the usual 3-momentum regularization, when the absolute value of the external 3-momentum of the polarization is zero. Additionally, it respects the particle-antiparticle symmetry of meson states in the Nambu$-$Jona-Lasinio (NJL) model for all values of temperature and chemical potential. Without this symmetry, in-medium cross sections calculated in the 3-momentum regularized NJL model are not consistent. In order to demonstrate the difference between the usual 3-momentum regularization with the one proposed in this work, we study the quark-quark and quark-antiquark cross sections in both regularization schemes. To this end we use the standard $SU(3)$ NJL model, with four and six quark interactions. We observe major quantitative and qualitative differences when comparing quark-quark cross sections in both schemes. The quark-antiquark cross sections, on the other hand, are very similar in both regularizations, owning to the equivalence between the regularizations when the absolute value of the external 3-momentum is zero.
1210.0594
Gautam Bhattacharyya
Gautam Bhattacharyya and Tirtha Sankar Ray
Pushing the SUSY Higgs mass towards 125 GeV with a color adjoint
v2: 6 pages, 4 figures, estimate of fine-tuning and some more clarifying remarks added, published in PRD
Phys. Rev. D 87, 015017 (2013)
10.1103/PhysRevD.87.015017
SINP/TNP/2012/13, DO-TH 12/29
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We show that inclusion of a TeV scale chiral superfield transforming in the adjoint representation of the color SU(3) to the MSSM particle content modifies the renormalization group running of some parameters in such a way that a 125 GeV mass of the light Higgs boson is accommodated more comfortably than in cMSSM / mSUGRA. Put differently, the introduction of a color adjoint TeV scale superfield helps resurrecting lighter choices for the stop and gluino which are otherwise disfavored in cMSSM / mSUGRA.
[ { "created": "Mon, 1 Oct 2012 22:05:02 GMT", "version": "v1" }, { "created": "Mon, 14 Jan 2013 08:39:01 GMT", "version": "v2" } ]
2013-05-30
[ [ "Bhattacharyya", "Gautam", "" ], [ "Ray", "Tirtha Sankar", "" ] ]
We show that inclusion of a TeV scale chiral superfield transforming in the adjoint representation of the color SU(3) to the MSSM particle content modifies the renormalization group running of some parameters in such a way that a 125 GeV mass of the light Higgs boson is accommodated more comfortably than in cMSSM / mSUGRA. Put differently, the introduction of a color adjoint TeV scale superfield helps resurrecting lighter choices for the stop and gluino which are otherwise disfavored in cMSSM / mSUGRA.
1410.5673
Leonard Lesniak
Leonard Lesniak, Jean-Pierre Dedonder, Robert Kaminski and Benoit Loiseau
Dalitz plot analysis of D0 --> K0S pi+ pi- decays in a factorization approach
4 pages, 5 figures, contribution to the 13th International Workshop on Meson Production, Properties and Interaction, Krakow, Poland, 29th May - 3rd June 2014
null
10.1051/epjconf/20148105019
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A quasi two-body QCD factorization is used to study the D0 --> K0S pi+ pi decays. The presently available high-statistics Dalitz plot data of this process measured by the Belle and BABAR Collaborations are analyzed together with the tau- --> K0S pi- nu_tau decay data. The total experimental branching fraction is also included in the fits which show a very good overall agreement with the experimental Dalitz plot density distributions. The branching fractions of the dominant channels compare well with those of the isobar Belle or BABAR models. We show that the branching fractions corresponding to the annihilation amplitudes are significant.
[ { "created": "Tue, 21 Oct 2014 14:15:42 GMT", "version": "v1" } ]
2015-06-23
[ [ "Lesniak", "Leonard", "" ], [ "Dedonder", "Jean-Pierre", "" ], [ "Kaminski", "Robert", "" ], [ "Loiseau", "Benoit", "" ] ]
A quasi two-body QCD factorization is used to study the D0 --> K0S pi+ pi decays. The presently available high-statistics Dalitz plot data of this process measured by the Belle and BABAR Collaborations are analyzed together with the tau- --> K0S pi- nu_tau decay data. The total experimental branching fraction is also included in the fits which show a very good overall agreement with the experimental Dalitz plot density distributions. The branching fractions of the dominant channels compare well with those of the isobar Belle or BABAR models. We show that the branching fractions corresponding to the annihilation amplitudes are significant.
1409.5775
Yasuhiro Yamamoto
Yasuhiro Yamamoto
Unitarity bounds on scalar dark matter effective interactions at LHC
8 pages, 6 figures; v2:published version
Prog. Theor. Exp. Phys. (2014) 123B03
10.1093/ptep/ptu169
UG-FT-312/14,CAFPE-182/14
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the compatibility of the unitarity bound and the 8TeV LHC on the effective theory of the scalar dark matter. In several signals of effective interactions, mono-jet with missing energy events are studied. We found that, at least, if the dark matter mass is about 800GeV or heavier, contributions of events violating the unitarity are not negligible. The unitarity conditions in the 14TeV LHC are also calculated.
[ { "created": "Fri, 19 Sep 2014 19:30:03 GMT", "version": "v1" }, { "created": "Sat, 24 Jan 2015 17:04:22 GMT", "version": "v2" } ]
2015-01-27
[ [ "Yamamoto", "Yasuhiro", "" ] ]
We study the compatibility of the unitarity bound and the 8TeV LHC on the effective theory of the scalar dark matter. In several signals of effective interactions, mono-jet with missing energy events are studied. We found that, at least, if the dark matter mass is about 800GeV or heavier, contributions of events violating the unitarity are not negligible. The unitarity conditions in the 14TeV LHC are also calculated.
hep-ph/0311193
Roberto Sghedoni
R.Sghedoni
Resummed Transverse Momentum Distribution in b->s+gamma
Talk given at "XV IFAE: Incontri sulla Fisica delle Alte Energie", Lecce, Italy, 23-26 April 2003, 4 pages
null
null
UPRF-2003-28
hep-ph
null
We present the complete calculation of the transverse momentum distribution for the decay b-> s gamma. The contributions of the leading operator O_7 are computed: infrared logarithms are resummed with next-to-leading accuracy according to usual techniques of resummation. Non logarithmic terms are evaluated to O(alpha_S) by calculating one loop diagrams.
[ { "created": "Fri, 14 Nov 2003 14:59:50 GMT", "version": "v1" } ]
2007-05-23
[ [ "Sghedoni", "R.", "" ] ]
We present the complete calculation of the transverse momentum distribution for the decay b-> s gamma. The contributions of the leading operator O_7 are computed: infrared logarithms are resummed with next-to-leading accuracy according to usual techniques of resummation. Non logarithmic terms are evaluated to O(alpha_S) by calculating one loop diagrams.
2004.07423
Ahmad Jafar Arifi
A. J. Arifi, H. Nagahiro, A. Hosaka, K. Tanida
Roper-like resonances with various flavor contents and their two-pion emission decays
4 pages, 5 figures
Phys. Rev. D 101, 111502 (2020)
10.1103/PhysRevD.101.111502
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the three-body decay of the newly observed bottom baryon $\Lambda_b^*(6072)$ by LHCb; $\Lambda_b^*(6072) \to \Lambda_b \pi \pi$. Its mass about 500 MeV above the ground state $\Lambda_b$ and a broad width imply that the state could be an analogue of the Roper resonance of the nucleon $N(1440)$. In terms of sequential processes going through $\Sigma_b$ and $\Sigma_b^*$, we find that the observed invariant mass distribution is reproduced assuming its spin and parity $J^P = 1/2^+$. We discuss that the ratio of the two sequential processes and angular correlation of two pions are useful for the determination of spin and parity. We suggest further studies for the Roper resonance analogue in various flavor contents, raising an interesting and important question in baryon spectroscopy.
[ { "created": "Thu, 16 Apr 2020 02:26:51 GMT", "version": "v1" } ]
2020-07-01
[ [ "Arifi", "A. J.", "" ], [ "Nagahiro", "H.", "" ], [ "Hosaka", "A.", "" ], [ "Tanida", "K.", "" ] ]
We study the three-body decay of the newly observed bottom baryon $\Lambda_b^*(6072)$ by LHCb; $\Lambda_b^*(6072) \to \Lambda_b \pi \pi$. Its mass about 500 MeV above the ground state $\Lambda_b$ and a broad width imply that the state could be an analogue of the Roper resonance of the nucleon $N(1440)$. In terms of sequential processes going through $\Sigma_b$ and $\Sigma_b^*$, we find that the observed invariant mass distribution is reproduced assuming its spin and parity $J^P = 1/2^+$. We discuss that the ratio of the two sequential processes and angular correlation of two pions are useful for the determination of spin and parity. We suggest further studies for the Roper resonance analogue in various flavor contents, raising an interesting and important question in baryon spectroscopy.
1003.0941
Clifford Cheung
Clifford Cheung
Axion Protection from Flavor
16 pages, 2 figures
JHEP 1006:074,2010
10.1007/JHEP06(2010)074
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The QCD axion fails to solve the strong CP problem unless all explicit PQ violating, Planck-suppressed, dimension n<10 operators are forbidden or have exponentially small coefficients. We show that all theories with a QCD axion contain an irreducible source of explicit PQ violation which is proportional to the determinant of the Yukawa interaction matrix of colored fermions. Generically, this contribution is of low operator dimension and will drastically destabilize the axion potential, so its suppression is a necessary condition for solving the strong CP problem. We propose a mechanism whereby the PQ symmetry is kept exact up to n=12 with the help of the very same flavor symmetries which generate the hierarchical quark masses and mixings of the SM. This "axion flavor protection" is straightforwardly realized in theories which employ radiative fermion mass generation and grand unification. A universal feature of this construction is that the heavy quark Yukawa couplings are generated at the PQ breaking scale.
[ { "created": "Thu, 4 Mar 2010 00:56:06 GMT", "version": "v1" } ]
2014-11-20
[ [ "Cheung", "Clifford", "" ] ]
The QCD axion fails to solve the strong CP problem unless all explicit PQ violating, Planck-suppressed, dimension n<10 operators are forbidden or have exponentially small coefficients. We show that all theories with a QCD axion contain an irreducible source of explicit PQ violation which is proportional to the determinant of the Yukawa interaction matrix of colored fermions. Generically, this contribution is of low operator dimension and will drastically destabilize the axion potential, so its suppression is a necessary condition for solving the strong CP problem. We propose a mechanism whereby the PQ symmetry is kept exact up to n=12 with the help of the very same flavor symmetries which generate the hierarchical quark masses and mixings of the SM. This "axion flavor protection" is straightforwardly realized in theories which employ radiative fermion mass generation and grand unification. A universal feature of this construction is that the heavy quark Yukawa couplings are generated at the PQ breaking scale.
1301.3990
Seyda Ipek
Seyda Ipek
Light Axigluon Contributions to b-bbar and c-cbar Asymmetry and Constraints on Flavor Changing Axigluon Currents
23 pages, 13 figures
Phys. Rev. D 87, 116010 (2013)
10.1103/PhysRevD.87.116010
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The light axigluon model of Tavares and Schmaltz is a viable candidate to explain the Tevatron t-tbar forward-backward asymmetry. In this paper we present the forward-backward asymmetries for b-bbar and c-cbar systems predicted by the light axigluon. Furthermore, we modify this model to include flavor changing couplings of axigluons with the SM quarks. We constrain these couplings from the available neutral meson mixing data, and investigate their effects on the rare decay B^0_s -> mu^+ mu^-, CP violating D -> h^+ h^- and isospin violating B -> K^(*) mu^+ mu^- decays. We show that a light axigluon can contribute to the observed CP violation in D -> h^+ h^- decays.
[ { "created": "Thu, 17 Jan 2013 06:11:47 GMT", "version": "v1" }, { "created": "Fri, 5 Jul 2013 22:13:30 GMT", "version": "v2" } ]
2013-07-09
[ [ "Ipek", "Seyda", "" ] ]
The light axigluon model of Tavares and Schmaltz is a viable candidate to explain the Tevatron t-tbar forward-backward asymmetry. In this paper we present the forward-backward asymmetries for b-bbar and c-cbar systems predicted by the light axigluon. Furthermore, we modify this model to include flavor changing couplings of axigluons with the SM quarks. We constrain these couplings from the available neutral meson mixing data, and investigate their effects on the rare decay B^0_s -> mu^+ mu^-, CP violating D -> h^+ h^- and isospin violating B -> K^(*) mu^+ mu^- decays. We show that a light axigluon can contribute to the observed CP violation in D -> h^+ h^- decays.
hep-ph/9407278
Ofelia
F. Buccella, O. Pisanti, and F. Sannino
Energy-Charge Correlation in the $\pi^+\pi^-\pi^0$ Decay of $K_L$ and of Tagged Neutral Kaons
15 A4-pages LaTeX + 2 figures (available in hard copies from the authors upon request to pisanti@na.infn.it), preprint DSF-93/52, SUHEP-582
Z.Phys. C66 (1995) 135-140
10.1007/BF01496588
null
hep-ph
null
We relate the asymmetries in the charged pions energy in the decay into $\pi^+\pi^-\pi^0$ of $K_L$ and of the tagged neutral kaons. The former asymmetry is a given combination of $\Re(\epsilon)$, $\Im(\epsilon)$, and $|\epsilon'|$. Moreover, the non-violating CP asymmetry allows a test for the $\chi$PT predictions within the Zel'dovich approach for the final state interaction.
[ { "created": "Tue, 12 Jul 1994 10:23:05 GMT", "version": "v1" } ]
2009-10-28
[ [ "Buccella", "F.", "" ], [ "Pisanti", "O.", "" ], [ "Sannino", "F.", "" ] ]
We relate the asymmetries in the charged pions energy in the decay into $\pi^+\pi^-\pi^0$ of $K_L$ and of the tagged neutral kaons. The former asymmetry is a given combination of $\Re(\epsilon)$, $\Im(\epsilon)$, and $|\epsilon'|$. Moreover, the non-violating CP asymmetry allows a test for the $\chi$PT predictions within the Zel'dovich approach for the final state interaction.
hep-ph/0206011
Antonio Pich Zardoya
Antonio Pich
The Standard Model of Particle Physics: Status & Low-Energy Tests
12 pages, 6 Postscript Figures
Proceedings of the ESO-CERN-ESA Symposium on "Astronomy, Cosmology and Fundamental Physics" (Garching bei M\"unchen, Germany, 4-7 March 2002)
10.1007/10857580_10
IFIC/02-24, FTUV/02-0603
hep-ph
null
Precision measurements of low-energy observables provide stringent tests of the Standard Model structure and accurate determinations of its parameters. An overview of the present experimental status is presented. The main topics discussed are the muon anomalous magnetic moment, the asymptotic freedom of strong interactions, the lepton universality of gauge couplings, the quark flavour structure and CP violation.
[ { "created": "Mon, 3 Jun 2002 12:22:31 GMT", "version": "v1" } ]
2009-11-07
[ [ "Pich", "Antonio", "" ] ]
Precision measurements of low-energy observables provide stringent tests of the Standard Model structure and accurate determinations of its parameters. An overview of the present experimental status is presented. The main topics discussed are the muon anomalous magnetic moment, the asymptotic freedom of strong interactions, the lepton universality of gauge couplings, the quark flavour structure and CP violation.
1008.3129
Dmitri Melikhov
Wolfgang Lucha, Dmitri Melikhov, Silvano Simula
Heavy-meson decay constants from QCD sum rules
6 pages, Talk given at QCD@Work - International Workshop on QCD - Theory and Experiment, 20 - 23 June, 2010, Martina Franca Italy
AIP Conf.Proc.1317:310-315,2011
10.1063/1.3536576
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We sketch a recent sum-rule extraction of the decay constants of the heavy pseudoscalar mesons D, D_s, B, and B_s from the two-point correlator of heavy-light pseudoscalar currents [1]. Our main emphasis lies on the control over all the uncertainties in the decay constants, related both to the input QCD parameters and to the limited accuracy of the method of sum rules. Gaining this control has become possible by application of our new procedure of extracting hadron observables based on a dual threshold depending on the Borel parameter. For the charmed-meson decay constants, we find f_D=206.2\pm 7.3(OPE) \pm 5.1(syst) MeV, f_Ds=245.3\pm 15.7(OPE) \pm 4.5(syst) MeV. For the beauty mesons, the decay constants turn out to be extremely sensitive to the precise value of the MSbar mass of the b-quark, mb(mb). By requiring our sum-rule estimate to match the average of the lattice determinations of f_B, we extract the rather accurate value mb(mb)=(4.245\pm 0.025) GeV. Feeding this parameter value into our sum-rule formalism leads to the beauty-meson decay constants f_B = 193.4 \pm 12.3(OPE) \pm 4.3(syst) MeV, f_Bs =232.5 \pm 18.6(OPE) \pm 2.4(syst) MeV.
[ { "created": "Wed, 18 Aug 2010 16:33:25 GMT", "version": "v1" } ]
2011-02-01
[ [ "Lucha", "Wolfgang", "" ], [ "Melikhov", "Dmitri", "" ], [ "Simula", "Silvano", "" ] ]
We sketch a recent sum-rule extraction of the decay constants of the heavy pseudoscalar mesons D, D_s, B, and B_s from the two-point correlator of heavy-light pseudoscalar currents [1]. Our main emphasis lies on the control over all the uncertainties in the decay constants, related both to the input QCD parameters and to the limited accuracy of the method of sum rules. Gaining this control has become possible by application of our new procedure of extracting hadron observables based on a dual threshold depending on the Borel parameter. For the charmed-meson decay constants, we find f_D=206.2\pm 7.3(OPE) \pm 5.1(syst) MeV, f_Ds=245.3\pm 15.7(OPE) \pm 4.5(syst) MeV. For the beauty mesons, the decay constants turn out to be extremely sensitive to the precise value of the MSbar mass of the b-quark, mb(mb). By requiring our sum-rule estimate to match the average of the lattice determinations of f_B, we extract the rather accurate value mb(mb)=(4.245\pm 0.025) GeV. Feeding this parameter value into our sum-rule formalism leads to the beauty-meson decay constants f_B = 193.4 \pm 12.3(OPE) \pm 4.3(syst) MeV, f_Bs =232.5 \pm 18.6(OPE) \pm 2.4(syst) MeV.
hep-ph/0207208
Arjun Berera
Arjun Berera and Thomas W. Kephart
Inflation and Generalized O'Raifeartaigh SUSY models
5 pages, latex, In Press Physics Letters B 2003
Phys.Lett. B578 (2004) 1-6
10.1016/j.physletb.2003.10.060
null
hep-ph astro-ph hep-th
null
Thermal inflation usually requires an inflationary potential with nonrenormalizable operators (NROs). We demonstrate how O'Raifeartaigh models with or without NROs can provide thermal inflation and a solution to the moduli problem, as well as provide SUSY breaking. We then discuss a scenario where generalized O'Raifeartaigh potentials (with NROs) are included in a SUGRA where the supergravity and O'Raifeartaigh potentials provide negative and a positive contributions to the cosmological constant respectively. Tuning these contributions to nearly cancel can provide the present value of the dark energy.
[ { "created": "Wed, 17 Jul 2002 15:24:35 GMT", "version": "v1" }, { "created": "Tue, 28 Oct 2003 18:19:24 GMT", "version": "v2" } ]
2015-06-25
[ [ "Berera", "Arjun", "" ], [ "Kephart", "Thomas W.", "" ] ]
Thermal inflation usually requires an inflationary potential with nonrenormalizable operators (NROs). We demonstrate how O'Raifeartaigh models with or without NROs can provide thermal inflation and a solution to the moduli problem, as well as provide SUSY breaking. We then discuss a scenario where generalized O'Raifeartaigh potentials (with NROs) are included in a SUGRA where the supergravity and O'Raifeartaigh potentials provide negative and a positive contributions to the cosmological constant respectively. Tuning these contributions to nearly cancel can provide the present value of the dark energy.
1010.0892
Wei-jie Fu
Wei-jie Fu and Yue-liang Wu
Fourth-order Correlations of Conserved Charges in the QCD Thermodynamics
13 pages, 4 figures
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The fourth-order correlations of conserved charges, such as the baryon number, electric charge, and strangeness, are studied at finite temperature and nonzero baryon chemical potential in an effective model. It is found that the fourth-order correlations change rapidly and have three extrema during the chiral crossover with the increase of the baryon chemical potential. The absolute values of the extrema approach infinity when the thermodynamical system moves toward the QCD critical point and the fourth-order correlations are divergent at the critical point. The contour plots of the fourth-order correlations in the plane of the temperature and baryon chemical potential are given. It is noticed that all the fourth-order correlations of conserved charges, except for $\chi_{13}^{BS}$ and $\chi_{13}^{QS}$, are excellent probes to explore the QCD critical point in heavy ion collision experiments.
[ { "created": "Tue, 5 Oct 2010 14:17:51 GMT", "version": "v1" } ]
2015-03-17
[ [ "Fu", "Wei-jie", "" ], [ "Wu", "Yue-liang", "" ] ]
The fourth-order correlations of conserved charges, such as the baryon number, electric charge, and strangeness, are studied at finite temperature and nonzero baryon chemical potential in an effective model. It is found that the fourth-order correlations change rapidly and have three extrema during the chiral crossover with the increase of the baryon chemical potential. The absolute values of the extrema approach infinity when the thermodynamical system moves toward the QCD critical point and the fourth-order correlations are divergent at the critical point. The contour plots of the fourth-order correlations in the plane of the temperature and baryon chemical potential are given. It is noticed that all the fourth-order correlations of conserved charges, except for $\chi_{13}^{BS}$ and $\chi_{13}^{QS}$, are excellent probes to explore the QCD critical point in heavy ion collision experiments.
1009.2818
Masahiro Ibe
Masahiro Ibe, Yuri Shirman, Tsutomu T. Yanagida
Cascade supersymmetry breaking and low-scale gauge mediation
27 pages, 3 figures
JHEP 1012:027,2010
10.1007/JHEP12(2010)027
IPMU10-0140
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose a new class of models with gauge mediated supersymmetry breaking, the cascade supersymmetry breaking. This class of models is consistent with the gravitino mass as low as O(1)eV without having suppressed gaugino masses, nor the Landau pole problems of the gauge coupling constants of the Standard Model below the scale of the grand unification. In particular, there is no supersymmetric vacuum in the vicinity of the supersymmetry breaking vacuum even for such a low gravitino mass. Thus, the model does not have a vacuum stability problem decaying into supersymmetric vacua.
[ { "created": "Wed, 15 Sep 2010 02:13:25 GMT", "version": "v1" }, { "created": "Fri, 8 Oct 2010 05:32:29 GMT", "version": "v2" } ]
2010-12-14
[ [ "Ibe", "Masahiro", "" ], [ "Shirman", "Yuri", "" ], [ "Yanagida", "Tsutomu T.", "" ] ]
We propose a new class of models with gauge mediated supersymmetry breaking, the cascade supersymmetry breaking. This class of models is consistent with the gravitino mass as low as O(1)eV without having suppressed gaugino masses, nor the Landau pole problems of the gauge coupling constants of the Standard Model below the scale of the grand unification. In particular, there is no supersymmetric vacuum in the vicinity of the supersymmetry breaking vacuum even for such a low gravitino mass. Thus, the model does not have a vacuum stability problem decaying into supersymmetric vacua.
1704.06993
M. N. Rebelo
G. C. Branco and M. N. Rebelo
The discrete charm of flavour and CP violation
10 pages, no figures. Prepared for the proceedings of DISCRETE2016: the Fifth Symposium on Prospects in the Physics of Discrete Symmetries, 28 November-3 December 2016, University of Warsaw, Poland, to appear in the Journal of Physics: Conference Series (JPCS)
null
10.1088/1742-6596/873/1/012011
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We point out that in the Standard Model (SM) there is no explanation why $|V_{23}|^2 + |V_{13}|^2$ is of order $10^{-3}$. A framework is described for explaining this small mixing, involving the introduction of vector-like quarks. A symmetry is introduced so that at a first stage $V_{CKM} = 1\>\!\!\!\mathrm{I}$ and only the third generation of quarks acquires a mass. It is shown that when interactions of vector-like quarks are taken into account a realistic quark mass spectrum is generated together with a correct $V_{CKM}$ matrix.
[ { "created": "Sun, 23 Apr 2017 22:28:37 GMT", "version": "v1" } ]
2017-09-13
[ [ "Branco", "G. C.", "" ], [ "Rebelo", "M. N.", "" ] ]
We point out that in the Standard Model (SM) there is no explanation why $|V_{23}|^2 + |V_{13}|^2$ is of order $10^{-3}$. A framework is described for explaining this small mixing, involving the introduction of vector-like quarks. A symmetry is introduced so that at a first stage $V_{CKM} = 1\>\!\!\!\mathrm{I}$ and only the third generation of quarks acquires a mass. It is shown that when interactions of vector-like quarks are taken into account a realistic quark mass spectrum is generated together with a correct $V_{CKM}$ matrix.
1204.5572
Thorsten Renk
Thorsten Renk
Energy dependence of the dijet imbalance in Pb-Pb collisions at 2.76 ATeV
4 pages, 1 figure
null
10.1103/PhysRevC.86.061901
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The appearance of monojets is among the most striking signature of jet quenching in the context of ultrarelativistic heavy-ion collisions at the Large Hadron Collider. Experimentally, the asymmetry of back-to-back jets is quantified in terms of the dijet imbalance distribution by the ATLAS and CMS collaborations. Recently, the CMS collaboration has also studied the trigger jet momentum (P_T) dependence of the imbalance in the range between 120 and 500 GeV which is found to decrease with jet P_T. In this work, results from the in-medium shower code YaJEM are compared with this data set. These results suggest that the main effects observed in the data are the kinematical collimation of jets and the increase in the probability to produce more collimated quark jets with jet P_T, whereas there is no indication for any non-trivial energy dependence of the shower-medium interaction mechanism itself. The data furthermore can rule out models in which the jet shape is collimated due to the medium modification.
[ { "created": "Wed, 25 Apr 2012 06:47:46 GMT", "version": "v1" } ]
2013-05-30
[ [ "Renk", "Thorsten", "" ] ]
The appearance of monojets is among the most striking signature of jet quenching in the context of ultrarelativistic heavy-ion collisions at the Large Hadron Collider. Experimentally, the asymmetry of back-to-back jets is quantified in terms of the dijet imbalance distribution by the ATLAS and CMS collaborations. Recently, the CMS collaboration has also studied the trigger jet momentum (P_T) dependence of the imbalance in the range between 120 and 500 GeV which is found to decrease with jet P_T. In this work, results from the in-medium shower code YaJEM are compared with this data set. These results suggest that the main effects observed in the data are the kinematical collimation of jets and the increase in the probability to produce more collimated quark jets with jet P_T, whereas there is no indication for any non-trivial energy dependence of the shower-medium interaction mechanism itself. The data furthermore can rule out models in which the jet shape is collimated due to the medium modification.
hep-ph/0110060
Michael C. Birse
Alexander N. Kvinikhidze, Michael C. Birse (University of Manchester), Boris Blankleider (Flinders University)
Pionic dressing of baryons in chiral quark models
14 pages, 4 figures (RevTeX, epsf) Further discussion and references added
Phys.Rev. C66 (2002) 045203
10.1103/PhysRevC.66.045203
null
hep-ph
null
We present a method for constructing the complete set of meson-exchange corrections to baryon observables described by covariant chiral quark models. The meson corrections are expressed in terms of an unperturbed valence-quark Green's function. This method is illustrated for the case of an NJL model. It also enables us to discuss, in terms of approximations used for this unperturbed Green's function, the treatments of meson corrections in two other chiral quark models.
[ { "created": "Thu, 4 Oct 2001 11:52:45 GMT", "version": "v1" }, { "created": "Wed, 1 May 2002 09:01:46 GMT", "version": "v2" }, { "created": "Wed, 14 Aug 2002 08:56:49 GMT", "version": "v3" } ]
2009-11-07
[ [ "Kvinikhidze", "Alexander N.", "", "University of Manchester" ], [ "Birse", "Michael C.", "", "University of Manchester" ], [ "Blankleider", "Boris", "", "Flinders University" ] ]
We present a method for constructing the complete set of meson-exchange corrections to baryon observables described by covariant chiral quark models. The meson corrections are expressed in terms of an unperturbed valence-quark Green's function. This method is illustrated for the case of an NJL model. It also enables us to discuss, in terms of approximations used for this unperturbed Green's function, the treatments of meson corrections in two other chiral quark models.
hep-ph/9903301
Per Osland
P. Osland (Bergen)
Higgs boson production in e^+e^- and e^-e^- collisions
18 pages, LaTeX, including 13 figures. Invited paper, Epiphany Conference on Electron-Positron Colliders, Cracow, January 1999, to appear in the proceedings
Acta Phys.Polon.B30:1967-1984,1999
null
Bergen 1999-02
hep-ph
null
When Higgs boson candidates will be found at future colliders, it becomes imperative to determine their properties, beyond the mass, production cross section and decay rates. Other crucial properties are those related to the behaviour under CP transformations, and the self-couplings. This paper addresses the question of measurability of some of the trilinear couplings of MSSM neutral Higgs bosons at a high-energy e^+e^- collider, and the possibilities of exploring the Higgs boson CP properties at e^+e^- and e^-e^- colliders.
[ { "created": "Tue, 9 Mar 1999 19:30:00 GMT", "version": "v1" } ]
2014-11-17
[ [ "Osland", "P.", "", "Bergen" ] ]
When Higgs boson candidates will be found at future colliders, it becomes imperative to determine their properties, beyond the mass, production cross section and decay rates. Other crucial properties are those related to the behaviour under CP transformations, and the self-couplings. This paper addresses the question of measurability of some of the trilinear couplings of MSSM neutral Higgs bosons at a high-energy e^+e^- collider, and the possibilities of exploring the Higgs boson CP properties at e^+e^- and e^-e^- colliders.
hep-ph/0601239
Hyun-Chul Kim
Antonio Silva, Hyun-Chul Kim, Diana Urbano, Klaus Goeke
Parity-violating aysmmetries in elastic $\vec{e}p$ scattering in the chiral quark-soliton model: Comparison with A4, G0, HAPPEX and SAMPLE
11 pages, 11 figures
Phys.Rev.D74:054011,2006
10.1103/PhysRevD.74.054011
PNU-NTG-11/2005, RUB-TPII-09/2005
hep-ph
null
We investigate parity-violating electroweak asymmetries in the elastic scattering of polarized electrons off protons within the framework of the chiral quark-soliton model ($\chi$QSM). We use as input the former results of the electromagnetic and strange form factors and newly calculated SU(3) axial-vector form factors, all evaluated with the same set of four parameters adjusted several years ago to general mesonic and baryonic properties. Based on this scheme, which yields positive electric and magnetic strange form factors with a $\mu_s=(0.08-0.13)\mu_N$, we determine the parity-violating asymmetries of elastic polarized electron-proton scattering. The results are in a good agreement with the data of the A4, HAPPEX, and SAMPLE experiments and reproduce the full $Q^2$-range of the G0-data. We also predict the parity-violating asymmetries for the backward G0 experiment.
[ { "created": "Sun, 29 Jan 2006 05:59:56 GMT", "version": "v1" } ]
2008-11-26
[ [ "Silva", "Antonio", "" ], [ "Kim", "Hyun-Chul", "" ], [ "Urbano", "Diana", "" ], [ "Goeke", "Klaus", "" ] ]
We investigate parity-violating electroweak asymmetries in the elastic scattering of polarized electrons off protons within the framework of the chiral quark-soliton model ($\chi$QSM). We use as input the former results of the electromagnetic and strange form factors and newly calculated SU(3) axial-vector form factors, all evaluated with the same set of four parameters adjusted several years ago to general mesonic and baryonic properties. Based on this scheme, which yields positive electric and magnetic strange form factors with a $\mu_s=(0.08-0.13)\mu_N$, we determine the parity-violating asymmetries of elastic polarized electron-proton scattering. The results are in a good agreement with the data of the A4, HAPPEX, and SAMPLE experiments and reproduce the full $Q^2$-range of the G0-data. We also predict the parity-violating asymmetries for the backward G0 experiment.
1401.0080
Tilman Plehn
Kyle Cranmer, Sven Kreiss, David Lopez-Val and Tilman Plehn
Decoupling Theoretical Uncertainties from Measurements of the Higgs Boson
published version
Phys. Rev. D 91, 054032 (2015)
10.1103/PhysRevD.91.054032
null
hep-ph physics.data-an
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We develop a technique to present Higgs coupling measurements, which decouple the poorly defined theoretical uncertainties associated to inclusive and exclusive cross section predictions. The technique simplifies the combination of multiple measurements and can be used in a more general setting. We illustrate the approach with toy LHC Higgs coupling measurements and a collection of new physics models.
[ { "created": "Tue, 31 Dec 2013 03:34:39 GMT", "version": "v1" }, { "created": "Tue, 28 Oct 2014 20:31:09 GMT", "version": "v2" }, { "created": "Wed, 1 Apr 2015 08:29:55 GMT", "version": "v3" } ]
2015-04-08
[ [ "Cranmer", "Kyle", "" ], [ "Kreiss", "Sven", "" ], [ "Lopez-Val", "David", "" ], [ "Plehn", "Tilman", "" ] ]
We develop a technique to present Higgs coupling measurements, which decouple the poorly defined theoretical uncertainties associated to inclusive and exclusive cross section predictions. The technique simplifies the combination of multiple measurements and can be used in a more general setting. We illustrate the approach with toy LHC Higgs coupling measurements and a collection of new physics models.
1706.02722
Kevin Kelly
Jeffrey M. Berryman, Andr\'e de Gouv\^ea, Kevin J. Kelly, and Yue Zhang
Dark Matter and Neutrino Mass from the Smallest Non-Abelian Chiral Dark Sector
35 pages, 7 figures. Matches published version
Phys. Rev. D 96, 075010 (2017)
10.1103/PhysRevD.96.075010
NUHEP-TH/17-04
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
All pieces of concrete evidence for phenomena outside the standard model (SM) - neutrino masses and dark matter - are consistent with the existence of new degrees of freedom that interact very weakly, if at all, with those in the SM. We propose that these new degrees of freedom organize themselves into a simple dark sector, a chiral SU(3) x SU(2) gauge theory with the smallest nontrivial fermion content. Similar to the SM, the dark SU(2) is spontaneously broken while the dark SU(3) confines at low energies. At the renormalizable level, the dark sector contains massless fermions - dark leptons - and stable massive particles - dark protons. We find that dark protons with masses between 10-100 TeV satisfy all current cosmological and astrophysical observations concerning dark matter even if dark protons are a symmetric thermal relic. The dark leptons play the role of right-handed neutrinos and allow simple realizations of the seesaw mechanism or the possibility that neutrinos are Dirac fermions. In the latter case, neutrino masses are also parametrically different from charged-fermion masses and the lightest neutrino is predicted to be massless. Since the new "neutrino" and "dark matter" degrees of freedom interact with one another, these two new-physics phenomena are intertwined. Dark leptons play a nontrivial role in early universe cosmology while indirect searches for dark matter involve, decisively, dark matter annihilations into dark leptons. These, in turn, may lead to observable signatures at high-energy neutrino and gamma-ray observatories, especially once one accounts for the potential Sommerfeld enhancement of the annihilation cross-section, derived from the low-energy dark-sector effective theory, a possibility we explore quantitatively in some detail.
[ { "created": "Thu, 8 Jun 2017 18:13:43 GMT", "version": "v1" }, { "created": "Mon, 16 Oct 2017 19:16:20 GMT", "version": "v2" } ]
2017-10-18
[ [ "Berryman", "Jeffrey M.", "" ], [ "de Gouvêa", "André", "" ], [ "Kelly", "Kevin J.", "" ], [ "Zhang", "Yue", "" ] ]
All pieces of concrete evidence for phenomena outside the standard model (SM) - neutrino masses and dark matter - are consistent with the existence of new degrees of freedom that interact very weakly, if at all, with those in the SM. We propose that these new degrees of freedom organize themselves into a simple dark sector, a chiral SU(3) x SU(2) gauge theory with the smallest nontrivial fermion content. Similar to the SM, the dark SU(2) is spontaneously broken while the dark SU(3) confines at low energies. At the renormalizable level, the dark sector contains massless fermions - dark leptons - and stable massive particles - dark protons. We find that dark protons with masses between 10-100 TeV satisfy all current cosmological and astrophysical observations concerning dark matter even if dark protons are a symmetric thermal relic. The dark leptons play the role of right-handed neutrinos and allow simple realizations of the seesaw mechanism or the possibility that neutrinos are Dirac fermions. In the latter case, neutrino masses are also parametrically different from charged-fermion masses and the lightest neutrino is predicted to be massless. Since the new "neutrino" and "dark matter" degrees of freedom interact with one another, these two new-physics phenomena are intertwined. Dark leptons play a nontrivial role in early universe cosmology while indirect searches for dark matter involve, decisively, dark matter annihilations into dark leptons. These, in turn, may lead to observable signatures at high-energy neutrino and gamma-ray observatories, especially once one accounts for the potential Sommerfeld enhancement of the annihilation cross-section, derived from the low-energy dark-sector effective theory, a possibility we explore quantitatively in some detail.
hep-ph/9402328
Luc Marleau
B.Dion and L. Marleau
Skyrmion solutions by generalization of the Atiyah-Manton ansatz
12 pages, revtex v3, EP-CPTh.A280.0194 and LAVAL-PHY-12-93
Phys.Rev.D49:5526-5531,1994
10.1103/PhysRevD.49.5526
null
hep-ph
null
We generalize the approach of Atiyah and Manton for generating Skyrmion configurations from instantons. The result is a series which parameters are found directly from the chiral angle equation. The series converge rapidly to the exact solution for a class of the Skyrme-like models (including the Skyrme model itself) but describe with less accuracy other types of models. We describe the procedure and discuss its advantages and limitations.
[ { "created": "Mon, 21 Feb 1994 11:20:30 GMT", "version": "v1" }, { "created": "Wed, 2 Mar 1994 16:02:46 GMT", "version": "v2" } ]
2008-11-26
[ [ "Dion", "B.", "" ], [ "Marleau", "L.", "" ] ]
We generalize the approach of Atiyah and Manton for generating Skyrmion configurations from instantons. The result is a series which parameters are found directly from the chiral angle equation. The series converge rapidly to the exact solution for a class of the Skyrme-like models (including the Skyrme model itself) but describe with less accuracy other types of models. We describe the procedure and discuss its advantages and limitations.
1408.3219
Juan Barranco
J. Barranco, D. Delepine, V. Gonzalez Macias, C. Lujan-Peschard and M. Napsuciale
Scattering processes could distinguish Majorana from Dirac neutrinos
12 pages, 5 figures
null
10.1016/j.physletb.2014.11.008
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It is well known that Majorana neutrinos have a pure axial neutral current interaction while Dirac neutrinos have the standard vector-axial interaction. In spite of this crucial difference, usually Dirac neutrino processes differ from Majorana processes by a term proportional to the neutrino mass, resulting in almost unmeasurable observations of this difference. In the present work we show that once the neutrino polarization evolution is considered, there are clear differences between Dirac and Majorana scattering on electrons. The change of polarization can be achieved in astrophysical environments with strong magnetic fields. Furthermore, we show that in the case of unpolarized neutrino scattering onto polarized electrons, this difference can be relevant even for large values of the neutrino energy.
[ { "created": "Thu, 14 Aug 2014 08:42:57 GMT", "version": "v1" } ]
2015-06-22
[ [ "Barranco", "J.", "" ], [ "Delepine", "D.", "" ], [ "Macias", "V. Gonzalez", "" ], [ "Lujan-Peschard", "C.", "" ], [ "Napsuciale", "M.", "" ] ]
It is well known that Majorana neutrinos have a pure axial neutral current interaction while Dirac neutrinos have the standard vector-axial interaction. In spite of this crucial difference, usually Dirac neutrino processes differ from Majorana processes by a term proportional to the neutrino mass, resulting in almost unmeasurable observations of this difference. In the present work we show that once the neutrino polarization evolution is considered, there are clear differences between Dirac and Majorana scattering on electrons. The change of polarization can be achieved in astrophysical environments with strong magnetic fields. Furthermore, we show that in the case of unpolarized neutrino scattering onto polarized electrons, this difference can be relevant even for large values of the neutrino energy.
hep-ph/0205167
Anne Billups
A.H. Mueller, D.N. Triantafyllopoulos (Columbia University)
The Energy Dependence of the Saturation Momentum
27 pages, 4 figures, Latex
Nucl.Phys. B640 (2002) 331-350
10.1016/S0550-3213(02)00581-3
CU-TP-1057
hep-ph
null
We study BFKL evolution and, in particular, the energy dependence of the saturation momentum in the presence of saturation boundaries limiting the region of linear BFKL evolution. In the case of fixed coupling evolution we confirm the previously found exponential term in $Q_s(Y)$ and determine the prefactor $Y$ and $\alpha$ dependences. In the running coupling case we find $Y^{1/6}$ corrections to the $Y^{1/2}$exponential behavior previously known. Geometrical scaling of the scattering amplitude is valid in a wide-range of momenta for fixed coupling evolution and in a more restricted region for running coupling evolution.
[ { "created": "Wed, 15 May 2002 16:53:00 GMT", "version": "v1" } ]
2015-06-25
[ [ "Mueller", "A. H.", "", "Columbia University" ], [ "Triantafyllopoulos", "D. N.", "", "Columbia University" ] ]
We study BFKL evolution and, in particular, the energy dependence of the saturation momentum in the presence of saturation boundaries limiting the region of linear BFKL evolution. In the case of fixed coupling evolution we confirm the previously found exponential term in $Q_s(Y)$ and determine the prefactor $Y$ and $\alpha$ dependences. In the running coupling case we find $Y^{1/6}$ corrections to the $Y^{1/2}$exponential behavior previously known. Geometrical scaling of the scattering amplitude is valid in a wide-range of momenta for fixed coupling evolution and in a more restricted region for running coupling evolution.
1112.2573
Edward Shuryak
Edward Shuryak
Toward the AdS/CFT dual of the "Little Bang"
a review to appear in topical volume of reviews collected by editors, S.Bass and G.Casaladerrey-Solana
null
10.1088/0954-3899/39/5/054001
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This (rather subjective) review sums up few years of work devoted to explain various aspects of high energy heavy ion collisions using the AdS/CFT correspondence. The central issue of is is formation of the trapped surface (black hole) phenomenon, seen by a distant observer as the entropy production. We end up discussing an issue of classical gravitational radiation by an ultrarelativistic falling body and the so called breaking self-force related to it.
[ { "created": "Mon, 12 Dec 2011 14:54:55 GMT", "version": "v1" } ]
2015-06-03
[ [ "Shuryak", "Edward", "" ] ]
This (rather subjective) review sums up few years of work devoted to explain various aspects of high energy heavy ion collisions using the AdS/CFT correspondence. The central issue of is is formation of the trapped surface (black hole) phenomenon, seen by a distant observer as the entropy production. We end up discussing an issue of classical gravitational radiation by an ultrarelativistic falling body and the so called breaking self-force related to it.
hep-ph/0101019
Vergados Ioannis
J.D. Vergados (Theoretical Physics Division, University of Ioannina)
Searching for Supersymmetric Dark Matter - The Directional Rate and the Modulation Effect Due to Caustic Rings
31 LATEX pages, 2 tables and 1 figure included. Accepted for publication in Physical Review D
Phys.Rev.D63:063511,2001
10.1103/PhysRevD.63.063511
null
hep-ph
null
The detection of the theoretically expected dark matter is central to particle physics and cosmology. Current fashionable supersymmetric models provide a natural dark matter candidate which is the lightest supersymmetric particle (LSP). The allowed parameter space of such models combined with fairly well understood physics (quark substructure of the nucleon and nuclear structure) permit the evaluation of the event rate for LSP-nucleus elastic scattering. The thus obtained event rates, which sensitively depend on the allowed parameter space parameters, are usually very low or even undetectable. So, for background reduction, one would like to exploit two nice features of the reaction, the directional rate, which depends on the sun's direction of motion and the modulation effect, i.e. the dependence of the event rate on the earth's annual motion. In the present paper we study these phenomena in a specific class of non isothermal models, which take into account the late in-fall of dark matter into our galaxy, producing flows of caustic rings. We find that the modulation effect arising from such models is smaller than that found previously with isothermal symmetric velocity distributions and much smaller compared to that obtained using a realistic asymmetric distribution with enhanced dispersion in the galactocentric direction.
[ { "created": "Tue, 2 Jan 2001 19:27:16 GMT", "version": "v1" } ]
2014-11-17
[ [ "Vergados", "J. D.", "", "Theoretical Physics Division, University of Ioannina" ] ]
The detection of the theoretically expected dark matter is central to particle physics and cosmology. Current fashionable supersymmetric models provide a natural dark matter candidate which is the lightest supersymmetric particle (LSP). The allowed parameter space of such models combined with fairly well understood physics (quark substructure of the nucleon and nuclear structure) permit the evaluation of the event rate for LSP-nucleus elastic scattering. The thus obtained event rates, which sensitively depend on the allowed parameter space parameters, are usually very low or even undetectable. So, for background reduction, one would like to exploit two nice features of the reaction, the directional rate, which depends on the sun's direction of motion and the modulation effect, i.e. the dependence of the event rate on the earth's annual motion. In the present paper we study these phenomena in a specific class of non isothermal models, which take into account the late in-fall of dark matter into our galaxy, producing flows of caustic rings. We find that the modulation effect arising from such models is smaller than that found previously with isothermal symmetric velocity distributions and much smaller compared to that obtained using a realistic asymmetric distribution with enhanced dispersion in the galactocentric direction.
hep-ph/0310276
Andrzej Czarnecki
Andrzej Czarnecki, William J. Marciano, and Arkady Vainshtein
Triangle Anomaly and the Muon g-2
9 pages, latex
Acta Phys.Polon. B34 (2003) 5669-5678
null
Alberta Thy 11-03
hep-ph
null
Hadronic electroweak corrections to the muon anomalous magnetic moment (g-2) are reviewed. Emphasis is on clarification of discrepancies among various published studies. A theorem on non-renormalization of the transversal part of a correlator of two vector currents and an axial current is reviewed and its consequences in the form of superconvergent sum rules are discussed.
[ { "created": "Thu, 23 Oct 2003 15:40:40 GMT", "version": "v1" } ]
2007-05-23
[ [ "Czarnecki", "Andrzej", "" ], [ "Marciano", "William J.", "" ], [ "Vainshtein", "Arkady", "" ] ]
Hadronic electroweak corrections to the muon anomalous magnetic moment (g-2) are reviewed. Emphasis is on clarification of discrepancies among various published studies. A theorem on non-renormalization of the transversal part of a correlator of two vector currents and an axial current is reviewed and its consequences in the form of superconvergent sum rules are discussed.
1704.05783
Mathieu Pellen
Benedikt Biedermann, Stephan Br\"auer, Ansgar Denner, Mathieu Pellen, Steffen Schumann, Jennifer M. Thompson
Automation of NLO QCD and EW corrections with Sherpa and Recola
38 pages, 29 figures. Matches the published version (few typos corrected)
Eur.Phys.J. C77 (2017) 492
10.1140/epjc/s10052-017-5054-8
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This publication presents the combination of the one-loop matrix-element generator Recola with the multipurpose Monte Carlo program Sherpa. Since both programs are highly automated, the resulting Sherpa+Recola framework allows for the computation of -in principle- any Standard Model process at both NLO QCD and EW accuracy. To illustrate this, three representative LHC processes have been computed at NLO QCD and EW: vector-boson production in association with jets, off-shell Z-boson pair production, and the production of a top-quark pair in association with a Higgs boson. In addition to fixed-order computations, when considering QCD corrections, all functionalities of Sherpa, i.e. particle decays, QCD parton showers, hadronisation, underlying events, etc. can be used in combination with Recola. This is demonstrated by the merging and matching of one-loop QCD matrix elements for Drell-Yan production in association with jets to the parton shower. The implementation is fully automatised, thus making it a perfect tool for both experimentalists and theorists who want to use state-of-the-art predictions at NLO accuracy.
[ { "created": "Wed, 19 Apr 2017 15:42:45 GMT", "version": "v1" }, { "created": "Thu, 27 Jul 2017 11:08:37 GMT", "version": "v2" } ]
2018-08-10
[ [ "Biedermann", "Benedikt", "" ], [ "Bräuer", "Stephan", "" ], [ "Denner", "Ansgar", "" ], [ "Pellen", "Mathieu", "" ], [ "Schumann", "Steffen", "" ], [ "Thompson", "Jennifer M.", "" ] ]
This publication presents the combination of the one-loop matrix-element generator Recola with the multipurpose Monte Carlo program Sherpa. Since both programs are highly automated, the resulting Sherpa+Recola framework allows for the computation of -in principle- any Standard Model process at both NLO QCD and EW accuracy. To illustrate this, three representative LHC processes have been computed at NLO QCD and EW: vector-boson production in association with jets, off-shell Z-boson pair production, and the production of a top-quark pair in association with a Higgs boson. In addition to fixed-order computations, when considering QCD corrections, all functionalities of Sherpa, i.e. particle decays, QCD parton showers, hadronisation, underlying events, etc. can be used in combination with Recola. This is demonstrated by the merging and matching of one-loop QCD matrix elements for Drell-Yan production in association with jets to the parton shower. The implementation is fully automatised, thus making it a perfect tool for both experimentalists and theorists who want to use state-of-the-art predictions at NLO accuracy.
2403.11702
Sreeraj Sreedharan Nair
Sreeraj Nair, Chandan Mondal, Siqi Xu, Xingbo Zhao, Asmita Mukherjee and James P. Vary
Gravitational Form Factors and Mechanical Properties of Quarks in Protons: A Basis Light-Front Quantization Approach
28 pages, 6 figures
null
null
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
We compute the gravitational form factors (GFFs) and study their applications for the description of the mechanical properties such as the pressure, shear force distributions, and the mechanical radius of the proton from its light-front wave functions (LFWFs) based on basis light-front quantization (BLFQ). The LFWFs of the proton are given by the lowest eigenvector of a light-front effective Hamiltonian that incorporates a three-dimensional confining potential and a one-gluon exchange interaction with fixed coupling between the constituent quarks solved in the valence Fock sector. We find acceptable agreement between our BLFQ computations and the lattice QCD for the GFFs. Our $D$-term form factor also agrees well with the extracted data from the deeply virtual Compton scattering experiments at Jefferson Lab, and the results of different phenomenological models. The distributions of pressures and shear forces are similar to those from different models.
[ { "created": "Mon, 18 Mar 2024 11:59:07 GMT", "version": "v1" } ]
2024-03-19
[ [ "Nair", "Sreeraj", "" ], [ "Mondal", "Chandan", "" ], [ "Xu", "Siqi", "" ], [ "Zhao", "Xingbo", "" ], [ "Mukherjee", "Asmita", "" ], [ "Vary", "James P.", "" ] ]
We compute the gravitational form factors (GFFs) and study their applications for the description of the mechanical properties such as the pressure, shear force distributions, and the mechanical radius of the proton from its light-front wave functions (LFWFs) based on basis light-front quantization (BLFQ). The LFWFs of the proton are given by the lowest eigenvector of a light-front effective Hamiltonian that incorporates a three-dimensional confining potential and a one-gluon exchange interaction with fixed coupling between the constituent quarks solved in the valence Fock sector. We find acceptable agreement between our BLFQ computations and the lattice QCD for the GFFs. Our $D$-term form factor also agrees well with the extracted data from the deeply virtual Compton scattering experiments at Jefferson Lab, and the results of different phenomenological models. The distributions of pressures and shear forces are similar to those from different models.
0902.0455
T. Lappi
T. Lappi
RHIC data and small x physics
6 pages, 7 figures, uses espcrc2.sty. Talk at the International Symposium on Very High Energy Cosmic Ray Interactions, Paris, France, September 2008
Nucl.Phys.Proc.Suppl.196:44-49,2009
10.1016/j.nuclphysbps.2009.09.007
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This is a short review of some RHIC results that have been most important for the small x physics community. We discuss saturation effects in deuteron-gold collisions, particle production in gold-gold collisions and some effects of the large "glasma" field configurations in the early stages of the collision.
[ { "created": "Tue, 3 Feb 2009 09:41:37 GMT", "version": "v1" } ]
2009-12-08
[ [ "Lappi", "T.", "" ] ]
This is a short review of some RHIC results that have been most important for the small x physics community. We discuss saturation effects in deuteron-gold collisions, particle production in gold-gold collisions and some effects of the large "glasma" field configurations in the early stages of the collision.
hep-ph/9705353
Rahul Basu
Rahul Basu (The Institute of Mathematical Sciences, Chennai (Madras), India)
HERA Physics - an overview of experimental and theoretical results
Latex, 21 pages, with postscript figures (included), presented at the XII DAE Symposium on High Energy Physics, 26 Dec 1996 -- 1 Jan 1997 at Guwahati, India}
null
null
IMSc-96/05/16
hep-ph
null
In this talk I review the low x QCD experimental results from HERA and their theoretical underpinnings. In particular, I discuss the structure function $F_2$, large rapidity gap events, pomeron structure functions and $J/\psi$ production.
[ { "created": "Mon, 19 May 1997 11:58:12 GMT", "version": "v1" } ]
2007-05-23
[ [ "Basu", "Rahul", "", "The Institute of Mathematical Sciences, Chennai" ] ]
In this talk I review the low x QCD experimental results from HERA and their theoretical underpinnings. In particular, I discuss the structure function $F_2$, large rapidity gap events, pomeron structure functions and $J/\psi$ production.
2205.03877
Norimi Yokozaki
Jason L. Evans, Tsutomu T. Yanagida, Norimi Yokozaki
W boson mass anomaly and grand unification
19 pages, 1 figure; references added
null
10.1016/j.physletb.2022.137306
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It is known that the recently reported shift of the W boson mass can be easily explained by an $SU(2)_L$ triplet Higgs boson with a zero hypercharge if it obtains a vacuum expectation value (VEV) of $O(1)$ GeV. Surprisingly, the addition of a TeV scale complex triplet Higgs boson to the standard model (SM) leads to a precise unification of the gauge couplings at around $10^{14}$ GeV. We consider that it is a consequence of $SU(5)$ grand unification and show a possible potential for the Higgs fields yielding a weak scale complex $SU(2)$ triplet scalar boson. Although it seems the proton decay constraint would doom such a low-scale unification, we show that the constraint can be avoided by introducing vector-like fermions which mix with the SM fermions through mass terms involving the VEV of GUT breaking Higgs field. Importantly, the simplest viable model only requires the addition of one pair of vector-like fermions transforming ${\bf 10}$ and $\overline{\bf 10}$.
[ { "created": "Sun, 8 May 2022 14:03:47 GMT", "version": "v1" }, { "created": "Wed, 18 May 2022 23:00:59 GMT", "version": "v2" } ]
2022-07-20
[ [ "Evans", "Jason L.", "" ], [ "Yanagida", "Tsutomu T.", "" ], [ "Yokozaki", "Norimi", "" ] ]
It is known that the recently reported shift of the W boson mass can be easily explained by an $SU(2)_L$ triplet Higgs boson with a zero hypercharge if it obtains a vacuum expectation value (VEV) of $O(1)$ GeV. Surprisingly, the addition of a TeV scale complex triplet Higgs boson to the standard model (SM) leads to a precise unification of the gauge couplings at around $10^{14}$ GeV. We consider that it is a consequence of $SU(5)$ grand unification and show a possible potential for the Higgs fields yielding a weak scale complex $SU(2)$ triplet scalar boson. Although it seems the proton decay constraint would doom such a low-scale unification, we show that the constraint can be avoided by introducing vector-like fermions which mix with the SM fermions through mass terms involving the VEV of GUT breaking Higgs field. Importantly, the simplest viable model only requires the addition of one pair of vector-like fermions transforming ${\bf 10}$ and $\overline{\bf 10}$.
hep-ph/0203080
Elena Perazzi
Z. Chacko (UC Berkeley and LBNL), E.Katz (Washington Univ.) and E.Perazzi (LBNL)
Yukawa Deflected Gauge Mediation in Four Dimensions
11 pages, 1figure
Phys.Rev. D66 (2002) 095012
10.1103/PhysRevD.66.095012
UW/PT-02-04, LBNL-49279
hep-ph
null
We construct a four dimensional realization of a higher dimensional model, Yukawa deflected gauge mediation, in which supersymmetry breaking is communicated to the visible sector through both gauge and Yukawa interactions. The reduction to four dimensions is achieved by `deconstructing' or `latticizing' the extra dimension. Three sites (gauge groups) are sufficient to reproduce the spectrum of the higher dimensional model. The characteristic features of Yukawa deflected gauge mediation, in particular, alignment of squarks and quarks, and a natural solution to the mu problem, carry over to the deconstructed version of the model. We comment on the implications of our results for a solution of the mu problem in the context of deconstructed gaugino mediation.
[ { "created": "Thu, 7 Mar 2002 23:15:19 GMT", "version": "v1" } ]
2009-11-07
[ [ "Chacko", "Z.", "", "UC Berkeley and LBNL" ], [ "Katz", "E.", "", "Washington Univ." ], [ "Perazzi", "E.", "", "LBNL" ] ]
We construct a four dimensional realization of a higher dimensional model, Yukawa deflected gauge mediation, in which supersymmetry breaking is communicated to the visible sector through both gauge and Yukawa interactions. The reduction to four dimensions is achieved by `deconstructing' or `latticizing' the extra dimension. Three sites (gauge groups) are sufficient to reproduce the spectrum of the higher dimensional model. The characteristic features of Yukawa deflected gauge mediation, in particular, alignment of squarks and quarks, and a natural solution to the mu problem, carry over to the deconstructed version of the model. We comment on the implications of our results for a solution of the mu problem in the context of deconstructed gaugino mediation.
1904.04517
Xu-Dong Huang
Xu-Dong Huang, Xing-Gang Wu, Jun Zeng, Qing Yu and Jian-Ming Shen
The $\Upsilon(1S)$ leptonic decay using the principle of maximum conformality
6 pages, 4 figures
Eur. Phys. J. C 79, 650 (2019)
10.1140/epjc/s10052-019-7158-9
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In the paper, we study the $\Upsilon(1S)$ leptonic decay width $\Gamma(\Upsilon(1S)\to \ell^+\ell^-)$ by using the principle of maximum conformality (PMC) scale-setting approach. The PMC adopts the renormalization group equation to set the correct momentum flow of the process, whose value is independent to the choice of the renormalization scale and its prediction thus avoids the conventional renormalization scale ambiguities. Using the known next-to-next-to-next-to-leading order perturbative series together with the PMC single scale-setting approach, we do obtain a renormalization scale independent decay width, $\Gamma_{\Upsilon(1S) \to e^+ e^-} = 1.262^{+0.195}_{-0.175}$ keV, where the error is squared average of those from $\alpha_s(M_{Z})=0.1181\pm0.0011$, $m_b=4.93\pm0.03$ GeV and the choices of factorization scales within $\pm 10\%$ of their central values. To compare with the result under conventional scale-setting approach, this decay width agrees with the experimental value within errors, indicating the importance of a proper scale-setting approach.
[ { "created": "Tue, 9 Apr 2019 08:17:47 GMT", "version": "v1" }, { "created": "Fri, 19 Jul 2019 05:08:33 GMT", "version": "v2" } ]
2019-08-13
[ [ "Huang", "Xu-Dong", "" ], [ "Wu", "Xing-Gang", "" ], [ "Zeng", "Jun", "" ], [ "Yu", "Qing", "" ], [ "Shen", "Jian-Ming", "" ] ]
In the paper, we study the $\Upsilon(1S)$ leptonic decay width $\Gamma(\Upsilon(1S)\to \ell^+\ell^-)$ by using the principle of maximum conformality (PMC) scale-setting approach. The PMC adopts the renormalization group equation to set the correct momentum flow of the process, whose value is independent to the choice of the renormalization scale and its prediction thus avoids the conventional renormalization scale ambiguities. Using the known next-to-next-to-next-to-leading order perturbative series together with the PMC single scale-setting approach, we do obtain a renormalization scale independent decay width, $\Gamma_{\Upsilon(1S) \to e^+ e^-} = 1.262^{+0.195}_{-0.175}$ keV, where the error is squared average of those from $\alpha_s(M_{Z})=0.1181\pm0.0011$, $m_b=4.93\pm0.03$ GeV and the choices of factorization scales within $\pm 10\%$ of their central values. To compare with the result under conventional scale-setting approach, this decay width agrees with the experimental value within errors, indicating the importance of a proper scale-setting approach.
2008.00360
Oleksandr Sobol Dr.
A. Boyarsky, V. Cheianov, O. Ruchayskiy, and O. Sobol
Equilibration of the chiral asymmetry due to finite electron mass in electron-positron plasma
43 pages, 20 figures
Phys. Rev. D 103, 013003 (2021)
10.1103/PhysRevD.103.013003
null
hep-ph astro-ph.CO hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We calculate the rate of collisional decay of the axial charge in an ultrarelativistic electron-positron plasma, also known as the chirality flipping rate. We find that contrary to the existing estimates, the chirality flipping rate appears already in the first order in the fine-structure constant $\alpha$ and is therefore orders of magnitude greater than previously believed. The main channels for the rapid relaxation of the axial charge are the collinear emission of a weakly damped photon and the Compton scattering. The latter contributes to the $\mathcal{O}(\alpha)$ result because of the infrared divergence in its cross section, which is regularized on the soft scale $\sim eT$ due to the thermal corrections. Our results are important for the description of the early Universe processes (such as leptogenesis or magnetogenesis) that affect differently left- and right-chiral fermions of the Standard Model, as discussed in more details in the companion Letter.
[ { "created": "Sat, 1 Aug 2020 23:28:36 GMT", "version": "v1" }, { "created": "Tue, 12 Jan 2021 18:08:33 GMT", "version": "v2" } ]
2021-01-20
[ [ "Boyarsky", "A.", "" ], [ "Cheianov", "V.", "" ], [ "Ruchayskiy", "O.", "" ], [ "Sobol", "O.", "" ] ]
We calculate the rate of collisional decay of the axial charge in an ultrarelativistic electron-positron plasma, also known as the chirality flipping rate. We find that contrary to the existing estimates, the chirality flipping rate appears already in the first order in the fine-structure constant $\alpha$ and is therefore orders of magnitude greater than previously believed. The main channels for the rapid relaxation of the axial charge are the collinear emission of a weakly damped photon and the Compton scattering. The latter contributes to the $\mathcal{O}(\alpha)$ result because of the infrared divergence in its cross section, which is regularized on the soft scale $\sim eT$ due to the thermal corrections. Our results are important for the description of the early Universe processes (such as leptogenesis or magnetogenesis) that affect differently left- and right-chiral fermions of the Standard Model, as discussed in more details in the companion Letter.
1311.2399
Muneto Nitta
Michikazu Kobayashi, Eiji Nakano, Muneto Nitta
Color Magnetism in Non-Abelian Vortex Matter
7 pages, no figures, published version
JHEP 1406,130:2014
10.1007/JHEP06(2014)130
null
hep-ph cond-mat.supr-con hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose color magnetism as a generalization of the ordinary Heisenberg (anti-)ferro magnets on a triangular lattice. Vortex matter consisting of an Abrikosov lattice of non-Abelian vortices with color magnetic fluxes shows a color ferro or anti-ferro magnetism, depending on the interaction among the vortex sites. A prime example is a non-Abelian vortex lattice in rotating dense quark matter, showing a color ferromagnetism. We show that the low-energy effective theory for the vortex lattice system in the color ferromagnetic phase is described by a 3+1 dimensional $CP^{N-1}$ nonlinear sigma model with spatially anisotropic couplings. We identify gapless excitations independent from Tkachenko modes as color magnons, that is, Nambu-Goldstone modes propagating in the vortex lattice with an anisotropic linear dispersion relation $\omega_p^2 = c_{xy}^2(p_x^2+p_y^2) + c_z^2 p_z^2$. We calculate the transition temperature between the ordered and disordered phases, and apply it to dense quark matter. We also identify the order parameter spaces for color anti-ferromagnets.
[ { "created": "Mon, 11 Nov 2013 10:06:43 GMT", "version": "v1" }, { "created": "Fri, 27 Jun 2014 15:54:09 GMT", "version": "v2" } ]
2014-06-30
[ [ "Kobayashi", "Michikazu", "" ], [ "Nakano", "Eiji", "" ], [ "Nitta", "Muneto", "" ] ]
We propose color magnetism as a generalization of the ordinary Heisenberg (anti-)ferro magnets on a triangular lattice. Vortex matter consisting of an Abrikosov lattice of non-Abelian vortices with color magnetic fluxes shows a color ferro or anti-ferro magnetism, depending on the interaction among the vortex sites. A prime example is a non-Abelian vortex lattice in rotating dense quark matter, showing a color ferromagnetism. We show that the low-energy effective theory for the vortex lattice system in the color ferromagnetic phase is described by a 3+1 dimensional $CP^{N-1}$ nonlinear sigma model with spatially anisotropic couplings. We identify gapless excitations independent from Tkachenko modes as color magnons, that is, Nambu-Goldstone modes propagating in the vortex lattice with an anisotropic linear dispersion relation $\omega_p^2 = c_{xy}^2(p_x^2+p_y^2) + c_z^2 p_z^2$. We calculate the transition temperature between the ordered and disordered phases, and apply it to dense quark matter. We also identify the order parameter spaces for color anti-ferromagnets.
hep-ph/0412261
Stephen Godfrey
Stephen Godfrey (Carleton) and Shou-hua Zhu (Carleton & Peking)
Study of V_LV_L to t tbar at the ILC Including O(alpha_s) QCD Corrections
8 pages, 8 figures, Minor changes in wording. uses Revtex4
Phys.Rev. D72 (2005) 074011
10.1103/PhysRevD.72.074011
null
hep-ph
null
In the event that the Higgs mass is large or that the electroweak interactions are strongly interacting at high energy, top quark couplings to longitudinal components of the weak gauge bosons could offer important clues to the underlying dynamics. It has been suggested that precision measurements of W_L W_L to t tbar and Z_L Z_L to t tbar might provide hints of new physics. In this paper we present results of O(alpha_s) QCD corrections to V_LV_L to t tbar scattering at the ILC. We find that corrections to cross sections can be as large as 30% and must be accounted for in any precision measurement of VV to t tbar.
[ { "created": "Fri, 17 Dec 2004 20:00:22 GMT", "version": "v1" }, { "created": "Fri, 26 Aug 2005 19:33:09 GMT", "version": "v2" }, { "created": "Wed, 14 Sep 2005 01:52:35 GMT", "version": "v3" } ]
2016-09-06
[ [ "Godfrey", "Stephen", "", "Carleton" ], [ "Zhu", "Shou-hua", "", "Carleton & Peking" ] ]
In the event that the Higgs mass is large or that the electroweak interactions are strongly interacting at high energy, top quark couplings to longitudinal components of the weak gauge bosons could offer important clues to the underlying dynamics. It has been suggested that precision measurements of W_L W_L to t tbar and Z_L Z_L to t tbar might provide hints of new physics. In this paper we present results of O(alpha_s) QCD corrections to V_LV_L to t tbar scattering at the ILC. We find that corrections to cross sections can be as large as 30% and must be accounted for in any precision measurement of VV to t tbar.
2009.10319
Jiaxing Zhao
Jiaxing Zhao, Shuzhe Shi, and Pengfei Zhuang
Fully-heavy tetraquarks in strongly interacting medium
13 pages, 5 figures
Phys. Rev. D. 102.114001(2020)
10.1103/PhysRevD.102.114001
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the properties of fully-heavy tetraquarks at finite temperature and their production in high-energy nuclear collisions. We obtain the masses and wave functions of the exotic hadron states $cc\bar c\bar c$ and $bb\bar b\bar b$ by solving the four-body Schr\"odinger equation in vacuum and strongly interacting matter. In vacuum, the tetraquarks are above the corresponding meson-meson mass threshold, and the newly observed exotic state $X(6900)$ might be a $cc\bar c\bar c$ state with quantum number $J^{PC}=0^{++}$ or $1^{+-}$. In hot medium, the temperature dependence of the tetraquark masses and the dissociation temperatures are calculated. Taking the wave function at finite temperature, we construct the Wigner function for the tetraquark states and calculate, with coalescence mechanism, the production yield and transverse momentum distribution of $cc\bar c\bar c$ in heavy-ion collisions at LHC energy. In comparison with nucleon-nucleon collisions, the yield per binary collision is significantly enhanced.
[ { "created": "Tue, 22 Sep 2020 04:57:01 GMT", "version": "v1" }, { "created": "Thu, 3 Dec 2020 02:05:33 GMT", "version": "v2" } ]
2020-12-04
[ [ "Zhao", "Jiaxing", "" ], [ "Shi", "Shuzhe", "" ], [ "Zhuang", "Pengfei", "" ] ]
We study the properties of fully-heavy tetraquarks at finite temperature and their production in high-energy nuclear collisions. We obtain the masses and wave functions of the exotic hadron states $cc\bar c\bar c$ and $bb\bar b\bar b$ by solving the four-body Schr\"odinger equation in vacuum and strongly interacting matter. In vacuum, the tetraquarks are above the corresponding meson-meson mass threshold, and the newly observed exotic state $X(6900)$ might be a $cc\bar c\bar c$ state with quantum number $J^{PC}=0^{++}$ or $1^{+-}$. In hot medium, the temperature dependence of the tetraquark masses and the dissociation temperatures are calculated. Taking the wave function at finite temperature, we construct the Wigner function for the tetraquark states and calculate, with coalescence mechanism, the production yield and transverse momentum distribution of $cc\bar c\bar c$ in heavy-ion collisions at LHC energy. In comparison with nucleon-nucleon collisions, the yield per binary collision is significantly enhanced.
0809.4503
Jacobus Verbaarschot
K. Splittorff and J.J.M. Verbaarschot
Lessons from Random Matrix Theory for QCD at Finite Density
Invited talk at "Continuous Advances in QCD 2008", Minneapolis, May 2008; 14 pages, 7 figures
null
10.1142/9789812838667_0014
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this lecture we discuss various aspects of QCD at nonzero chemical potential, including its phase diagram and the Dirac spectrum, and summarize what chiral random matrix theory has contributed to this subject. To illustrate the importance of the phase of the fermion determinant, we particularly highlight the differences between QCD and phase quenched QCD.
[ { "created": "Thu, 25 Sep 2008 21:09:43 GMT", "version": "v1" } ]
2017-08-23
[ [ "Splittorff", "K.", "" ], [ "Verbaarschot", "J. J. M.", "" ] ]
In this lecture we discuss various aspects of QCD at nonzero chemical potential, including its phase diagram and the Dirac spectrum, and summarize what chiral random matrix theory has contributed to this subject. To illustrate the importance of the phase of the fermion determinant, we particularly highlight the differences between QCD and phase quenched QCD.
0712.2933
Peihong Gu
Pei-Hong Gu, Utpal Sarkar
Radiative Neutrino Mass, Dark Matter and Leptogenesis
4 pages, 3 figures. Revised version with improved model. Accepted by PRD
Phys.Rev.D77:105031,2008
10.1103/PhysRevD.77.105031
null
hep-ph
null
We propose an extension of the standard model, in which neutrinos are Dirac particles and their tiny masses originate from a one-loop radiative diagram. The new fields required by the neutrino mass-generation also accommodate the explanation for the matter-antimatter asymmetry and dark matter in the universe.
[ { "created": "Tue, 18 Dec 2007 11:35:17 GMT", "version": "v1" }, { "created": "Tue, 22 Apr 2008 13:20:30 GMT", "version": "v2" } ]
2008-11-26
[ [ "Gu", "Pei-Hong", "" ], [ "Sarkar", "Utpal", "" ] ]
We propose an extension of the standard model, in which neutrinos are Dirac particles and their tiny masses originate from a one-loop radiative diagram. The new fields required by the neutrino mass-generation also accommodate the explanation for the matter-antimatter asymmetry and dark matter in the universe.
1905.07591
Kazem Azizi
S. S. Agaev, K. Azizi, H. Sundu
Double-heavy axial-vector tetraquark $T_{bc;\bar{u}\bar{d}}^{0}$
11 Pages, 3 Figures and 4 Tables
null
10.1016/j.nuclphysb.2019.114890
null
hep-ph hep-ex hep-lat
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The mass and coupling of the axial-vector tetraquark $T_{bc;\bar{u}\bar{d} }^{0}$ (in a short form $T_{bc}^{0}$) are calculated by means of the QCD two-point sum rule method. In computations we take into account contributions arising from various quark, gluon and mixed vacuum condensates up to dimension 10. The central value of the mass $m=(7105 \pm 155)~\mathrm{ MeV}$ lies below the thresholds for the strong and electromagnetic decays of $T_{bc}^{0}$ state, and hence it transforms to conventional mesons only through the weak decays. In the case of $m=7260~\mathrm{MeV}$ the tetraquark $T_{bc}^{0}$ becomes the strong- and electromagnetic-interaction unstable particle. In the first case, we find the full width and mean lifetime of $ T_{bc}^{0}$ using its dominant semileptonic decays $T_{bc}^{0}\to T_{cc;\bar{ u}\bar{d}}^{+}l\overline{\nu }_{l}$ ($l=e,\ \mu, \tau$), where the final-state tetraquark is a scalar state. We compute also partial widths of the nonleptonic weak decays $T_{bc}^{0}\to T_{cc;\bar{u}\bar{d} }^{+}\pi^{-}(K^{-}, D^{-}, D_{s}^{-})$, and take into account their effects on the full width of $T_{bc}^{0}$. In the context of the second scenario we calculate partial widths of $S$-wave strong decays $T_{bc}^{0}\to B^{\ast -}D^{+}$ and $T_{bc}^{0}\to \overline{B}^{\ast 0}D^{0}$, and using these channels evaluate the full width of $T_{bc}^{0}$. Predictions for $\Gamma_{ \mathrm{full}} =(3.98\pm 0.51)\times 10^{-10}~\mathrm{MeV}$ and mean lifetime $\tau=1.65_{-0.18}^{+0.25}~\mathrm{ps}$ of $T_{bc}^{0}$ obtained in the context of the first option, as well as the full width $\Gamma_{\mathrm{ full}}=(63.5\pm 8.9)~\mathrm{MeV}$ extracted in the second scenario may be useful for experimental and theoretical exploration of double-heavy exotic mesons.
[ { "created": "Sat, 18 May 2019 13:48:33 GMT", "version": "v1" }, { "created": "Wed, 26 Jun 2019 06:34:18 GMT", "version": "v2" }, { "created": "Fri, 26 Jul 2019 11:44:03 GMT", "version": "v3" }, { "created": "Mon, 26 Aug 2019 18:45:26 GMT", "version": "v4" } ]
2020-01-29
[ [ "Agaev", "S. S.", "" ], [ "Azizi", "K.", "" ], [ "Sundu", "H.", "" ] ]
The mass and coupling of the axial-vector tetraquark $T_{bc;\bar{u}\bar{d} }^{0}$ (in a short form $T_{bc}^{0}$) are calculated by means of the QCD two-point sum rule method. In computations we take into account contributions arising from various quark, gluon and mixed vacuum condensates up to dimension 10. The central value of the mass $m=(7105 \pm 155)~\mathrm{ MeV}$ lies below the thresholds for the strong and electromagnetic decays of $T_{bc}^{0}$ state, and hence it transforms to conventional mesons only through the weak decays. In the case of $m=7260~\mathrm{MeV}$ the tetraquark $T_{bc}^{0}$ becomes the strong- and electromagnetic-interaction unstable particle. In the first case, we find the full width and mean lifetime of $ T_{bc}^{0}$ using its dominant semileptonic decays $T_{bc}^{0}\to T_{cc;\bar{ u}\bar{d}}^{+}l\overline{\nu }_{l}$ ($l=e,\ \mu, \tau$), where the final-state tetraquark is a scalar state. We compute also partial widths of the nonleptonic weak decays $T_{bc}^{0}\to T_{cc;\bar{u}\bar{d} }^{+}\pi^{-}(K^{-}, D^{-}, D_{s}^{-})$, and take into account their effects on the full width of $T_{bc}^{0}$. In the context of the second scenario we calculate partial widths of $S$-wave strong decays $T_{bc}^{0}\to B^{\ast -}D^{+}$ and $T_{bc}^{0}\to \overline{B}^{\ast 0}D^{0}$, and using these channels evaluate the full width of $T_{bc}^{0}$. Predictions for $\Gamma_{ \mathrm{full}} =(3.98\pm 0.51)\times 10^{-10}~\mathrm{MeV}$ and mean lifetime $\tau=1.65_{-0.18}^{+0.25}~\mathrm{ps}$ of $T_{bc}^{0}$ obtained in the context of the first option, as well as the full width $\Gamma_{\mathrm{ full}}=(63.5\pm 8.9)~\mathrm{MeV}$ extracted in the second scenario may be useful for experimental and theoretical exploration of double-heavy exotic mesons.
hep-ph/0106093
Mu-Chun Chen
Mu-Chun Chen and K.T. Mahanthappa
CP Violation in a Supersymmetric SO(10) x U(2)_{F} Model
RevTeX4; 7 pages; typos corrected; clarification remarks added; more references added. To appear in Physical Review D
Phys.Rev.D65:053010,2002
10.1103/PhysRevD.65.053010
COLO-HEP-466
hep-ph
null
A model based on SUSY SO(10) combined with U(2) family symmetry constructed recently by the authors is generalized to include phases in the mass matrices leading to CP violation. In contrast with the commonly used effective operator approach, $\bar{126}$-dimensional Higgs fields are utilized to construct the Yukawa sector. R-parity symmetry is thus preserved at low energies. The symmetric mass textures arising from the left-right symmetry breaking chain of SO(10) give rise to very good predictions for quark and lepton masses and mixings. The prediction for $\sin 2\beta$ agrees with the average of current bounds from BaBar and Belle. In the neutrino sector, our predictions are in good agreement with results from atmospheric neutrino experiments. Our model favors both the LOW and QVO solutions to the solar neutrino anomaly; the matrix element for neutrinoless double beta decay is highly suppressed. The leptonic analog of the Jarlskog invariant, $J_{CP}^{l}$, is predicted to be of $O(10^{-2})$.
[ { "created": "Fri, 8 Jun 2001 19:03:11 GMT", "version": "v1" }, { "created": "Mon, 18 Jun 2001 22:45:29 GMT", "version": "v2" }, { "created": "Wed, 14 Nov 2001 21:06:02 GMT", "version": "v3" } ]
2014-11-17
[ [ "Chen", "Mu-Chun", "" ], [ "Mahanthappa", "K. T.", "" ] ]
A model based on SUSY SO(10) combined with U(2) family symmetry constructed recently by the authors is generalized to include phases in the mass matrices leading to CP violation. In contrast with the commonly used effective operator approach, $\bar{126}$-dimensional Higgs fields are utilized to construct the Yukawa sector. R-parity symmetry is thus preserved at low energies. The symmetric mass textures arising from the left-right symmetry breaking chain of SO(10) give rise to very good predictions for quark and lepton masses and mixings. The prediction for $\sin 2\beta$ agrees with the average of current bounds from BaBar and Belle. In the neutrino sector, our predictions are in good agreement with results from atmospheric neutrino experiments. Our model favors both the LOW and QVO solutions to the solar neutrino anomaly; the matrix element for neutrinoless double beta decay is highly suppressed. The leptonic analog of the Jarlskog invariant, $J_{CP}^{l}$, is predicted to be of $O(10^{-2})$.
2306.06395
Zhongyu Wang
Zhong-Yu Wang, Yu-Wen Peng, Jing-Yu Yi, W. C. Luo, and C. W. Xiao
Are the $a_{0}(1710)$ or $a_{0}(1817)$ resonances in the $D_{s}^{+} \rightarrow K_{S}^{0}K^{+}\pi^{0}$ decay?
null
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The BESIII Collaboration claimed that a new $a_{0}(1817)$ resonance was found in the recent results of the $D_{s}^{+} \rightarrow K_{S}^{0}K^{+}\pi^{0}$ decay. For this decay process, we perform a unitary amplitude to analyze the contributions of the states $a_{0}(980)^{+}$ and $a_{0}(1710)^{+}$ with the final state interactions. Considering the Cabibbo-favored external and internal $W$-emission mechanisms at the quark level, and the contributions of the resonances $a_{0}(980)^{+}$, $a_{0}(1710)^{+}$ in the $S$-wave and $\bar{K}^{*}(892)^{0}$, ${K}^{*}(892)^{+}$ in the $P$-wave, the recent experimental data of the $K_{S}^{0}K^{+}$ invariant mass spectrum from the BESIII Collaboration can be described well. In our results, the states $a_{0}(980)$ and $a_{0}(1710)$ are dynamically generated from the final state interactions of $K\bar{K}$ and $K^{*}\bar{K}^{*}$, respectively, which support the molecular nature for them. Moreover, some obtained branching fractions are in agreement with the experimental measurements.
[ { "created": "Sat, 10 Jun 2023 09:43:51 GMT", "version": "v1" } ]
2023-06-13
[ [ "Wang", "Zhong-Yu", "" ], [ "Peng", "Yu-Wen", "" ], [ "Yi", "Jing-Yu", "" ], [ "Luo", "W. C.", "" ], [ "Xiao", "C. W.", "" ] ]
The BESIII Collaboration claimed that a new $a_{0}(1817)$ resonance was found in the recent results of the $D_{s}^{+} \rightarrow K_{S}^{0}K^{+}\pi^{0}$ decay. For this decay process, we perform a unitary amplitude to analyze the contributions of the states $a_{0}(980)^{+}$ and $a_{0}(1710)^{+}$ with the final state interactions. Considering the Cabibbo-favored external and internal $W$-emission mechanisms at the quark level, and the contributions of the resonances $a_{0}(980)^{+}$, $a_{0}(1710)^{+}$ in the $S$-wave and $\bar{K}^{*}(892)^{0}$, ${K}^{*}(892)^{+}$ in the $P$-wave, the recent experimental data of the $K_{S}^{0}K^{+}$ invariant mass spectrum from the BESIII Collaboration can be described well. In our results, the states $a_{0}(980)$ and $a_{0}(1710)$ are dynamically generated from the final state interactions of $K\bar{K}$ and $K^{*}\bar{K}^{*}$, respectively, which support the molecular nature for them. Moreover, some obtained branching fractions are in agreement with the experimental measurements.
1302.5874
Xin-Nian Wang
Xin-Nian Wang (CCNU/LBNL) and Yan Zhu (U. Bielefeld)
Medium Modification of \gamma-jets in High-energy Heavy-ion Collisions
4 pages, 5 figures final version published
null
10.1103/PhysRevLett.111.062301
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Medium modification of \gamma-tagged jets in high-energy heavy-ion collisions is investigated within a Linearized Boltzmann Transport model for jet propagation that includes both elastic parton scattering and induced gluon emission. Inclusion of recoiled medium partons in the reconstruction of partonic jets is found to significantly reduce the net jet energy loss. Experimental data on \gamma-jet asymmetry and survival rate in Pb + Pb collisions at \sqrt{s}=2.76 TeV can be reproduced. Medium modifications of reconstructed jet fragmentation function, transverse profile and energy flow outside the jet-cone are found to be sizable especially for \gamma-tagged jets with small values of x=p_T^{jet}/p_T^\gamma.
[ { "created": "Sun, 24 Feb 2013 05:37:24 GMT", "version": "v1" }, { "created": "Sat, 17 Aug 2013 07:43:49 GMT", "version": "v2" } ]
2013-08-20
[ [ "Wang", "Xin-Nian", "", "CCNU/LBNL" ], [ "Zhu", "Yan", "", "U. Bielefeld" ] ]
Medium modification of \gamma-tagged jets in high-energy heavy-ion collisions is investigated within a Linearized Boltzmann Transport model for jet propagation that includes both elastic parton scattering and induced gluon emission. Inclusion of recoiled medium partons in the reconstruction of partonic jets is found to significantly reduce the net jet energy loss. Experimental data on \gamma-jet asymmetry and survival rate in Pb + Pb collisions at \sqrt{s}=2.76 TeV can be reproduced. Medium modifications of reconstructed jet fragmentation function, transverse profile and energy flow outside the jet-cone are found to be sizable especially for \gamma-tagged jets with small values of x=p_T^{jet}/p_T^\gamma.
0710.1508
Mustafa Savci
T. M. Aliev, K. Azizi, M. Savci
Analysis of rare (B -> K_0*(1430) l^+ l^- decay) within QCD sum rules
13 pages, 1 figure
Phys.Rev.D76:074017,2007
10.1103/PhysRevD.76.074017
metu-phys-hep-07-19
hep-ph
null
Form factors of rare (B -> K_0*(1430) l^+ l^-$ decay) decay are calculated within three-point QCD sum rules, with (K_0* (1430)) being the p-wave scalar meson. The branching ratios are estimated when only short, as well as short and long distance effects, are taken into account.It is obtained that the (B -> K_0*(1430) l^+ l^- (l=e,mu)) decay is measurable at LHC. Measurement of these branching ratios for the semileptonic rare (B -> K_0*(1430) l^+ l^-$ decay) can give valuable information about the nature of scalar meson (K_0* (1430)).
[ { "created": "Mon, 8 Oct 2007 10:50:01 GMT", "version": "v1" } ]
2008-11-26
[ [ "Aliev", "T. M.", "" ], [ "Azizi", "K.", "" ], [ "Savci", "M.", "" ] ]
Form factors of rare (B -> K_0*(1430) l^+ l^-$ decay) decay are calculated within three-point QCD sum rules, with (K_0* (1430)) being the p-wave scalar meson. The branching ratios are estimated when only short, as well as short and long distance effects, are taken into account.It is obtained that the (B -> K_0*(1430) l^+ l^- (l=e,mu)) decay is measurable at LHC. Measurement of these branching ratios for the semileptonic rare (B -> K_0*(1430) l^+ l^-$ decay) can give valuable information about the nature of scalar meson (K_0* (1430)).
0805.0768
Joao Pacheco B. C. de Melo Dr.
B. El-Bennich (LPNHE, France and ANL, USA), J. P. B. C. de Melo (LFTC, Universidade Cruzeiro do Sul and IFT, UNESP, Brazil), B. Loiseau (LPNHE, France), J.-P.Dedonder (LPNHE, France) and T. Frederico (ITA, CTA, Brazil)
Modeling electromagnetic form factors of light and heavy pseudoscalar mesons
6 pages, 4 figures, use revtex4. Figure 2 and references are corrected. Acknoledgments are added
Braz.J.Phys.38:465-471,2008
10.1590/S0103-97332008000400016
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The electromagnetic form factors of light and heavy pseudoscalar mesons are calculated within two covariant constituent-quark models, a light-front and a dispersion relation approach. We investigate the details and physical origins of the model dependence of various hadronic observables: the weak decay constant, the charge radius and the elastic electromagnetic form factor.
[ { "created": "Tue, 6 May 2008 19:56:29 GMT", "version": "v1" }, { "created": "Mon, 12 May 2008 14:54:49 GMT", "version": "v2" }, { "created": "Thu, 9 Oct 2008 18:02:54 GMT", "version": "v3" } ]
2011-08-31
[ [ "El-Bennich", "B.", "", "LPNHE, France and ANL, USA" ], [ "de Melo", "J. P. B. C.", "", "LFTC,\n Universidade Cruzeiro do Sul and IFT, UNESP, Brazil" ], [ "Loiseau", "B.", "", "LPNHE,\n France" ], [ "Dedonder", "J. -P.", "", "LPNHE, Fra...
The electromagnetic form factors of light and heavy pseudoscalar mesons are calculated within two covariant constituent-quark models, a light-front and a dispersion relation approach. We investigate the details and physical origins of the model dependence of various hadronic observables: the weak decay constant, the charge radius and the elastic electromagnetic form factor.
1003.1182
Pengzhi Huang
Peng-Zhi Huang, Liang Zhang, Shi-Lin Zhu
Strong and Electromagnetic Decays of The $D$-wave Heavy Mesons
20 pages, 13 figures
Phys.Rev.D81:094025,2010
10.1103/PhysRevD.81.094025
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We calculate the $\pi$, $\rho$, $\omega$, and $\gamma$ coupling constants between the heavy meson doublets $(1^-,2^-)$ and (0^-,1^-)/(0^+,1^+) within the framework of the light-cone QCD sum rule at the leading order of heavy quark effective theory. Most of the sum rules are stable with the variations of the Borel parameter and the continuum threshold. Then we calculate the strong and electromagnetic decay widths of the $(1^-,2^-)$ D-wave heavy mesons. Their total widths are around several tens of MeV, which is helpful in the future experimental search.
[ { "created": "Fri, 5 Mar 2010 04:17:25 GMT", "version": "v1" } ]
2010-06-01
[ [ "Huang", "Peng-Zhi", "" ], [ "Zhang", "Liang", "" ], [ "Zhu", "Shi-Lin", "" ] ]
We calculate the $\pi$, $\rho$, $\omega$, and $\gamma$ coupling constants between the heavy meson doublets $(1^-,2^-)$ and (0^-,1^-)/(0^+,1^+) within the framework of the light-cone QCD sum rule at the leading order of heavy quark effective theory. Most of the sum rules are stable with the variations of the Borel parameter and the continuum threshold. Then we calculate the strong and electromagnetic decay widths of the $(1^-,2^-)$ D-wave heavy mesons. Their total widths are around several tens of MeV, which is helpful in the future experimental search.
2312.02278
Timothy Hobbs
Brandon Kriesten and T. J. Hobbs
Learning PDFs through Interpretable Latent Representations in Mellin Space
22 pages, 11 figures; updated link to public code, https://github.com/ML4HEP-Theory/PDFDecoder
null
null
ANL-186490
hep-ph hep-lat nucl-th
http://creativecommons.org/licenses/by/4.0/
Representing the parton distribution functions (PDFs) of the proton and other hadrons through flexible, high-fidelity parametrizations has been a long-standing goal of particle physics phenomenology. This is particularly true since the chosen parametrization methodology can play an influential role in the ultimate PDF uncertainties as extracted in QCD global analyses; these, in turn, are often determinative of the reach of experiments at the LHC and other facilities to non-standard physics, including at large $x$, where parametrization effects can be significant. In this study, we explore a series of encoder-decoder machine-learning (ML) models with various neural-network topologies as efficient means of reconstructing PDFs from meaningful information stored in an interpretable latent space. Given recent effort to pioneer synergies between QCD analyses and lattice-gauge calculations, we formulate a latent representation based on the behavior of PDFs in Mellin space, i.e., their integrated moments, and test the ability of various models to decode PDFs from this information faithfully. We introduce a numerical package, $\texttt{PDFdecoder}$, which implements several encoder-decoder models to reconstruct PDFs with high fidelity and use this tool to explore strengths and pitfalls of neural-network approaches to PDF parametrization. We additionally dissect patterns of learned correlations between encoded Mellin moments and reconstructed PDFs which suggest opportunities for further improvements to ML-based approaches to PDF parametrizations and uncertainty quantification.
[ { "created": "Mon, 4 Dec 2023 19:00:23 GMT", "version": "v1" }, { "created": "Thu, 20 Jun 2024 14:46:15 GMT", "version": "v2" } ]
2024-06-21
[ [ "Kriesten", "Brandon", "" ], [ "Hobbs", "T. J.", "" ] ]
Representing the parton distribution functions (PDFs) of the proton and other hadrons through flexible, high-fidelity parametrizations has been a long-standing goal of particle physics phenomenology. This is particularly true since the chosen parametrization methodology can play an influential role in the ultimate PDF uncertainties as extracted in QCD global analyses; these, in turn, are often determinative of the reach of experiments at the LHC and other facilities to non-standard physics, including at large $x$, where parametrization effects can be significant. In this study, we explore a series of encoder-decoder machine-learning (ML) models with various neural-network topologies as efficient means of reconstructing PDFs from meaningful information stored in an interpretable latent space. Given recent effort to pioneer synergies between QCD analyses and lattice-gauge calculations, we formulate a latent representation based on the behavior of PDFs in Mellin space, i.e., their integrated moments, and test the ability of various models to decode PDFs from this information faithfully. We introduce a numerical package, $\texttt{PDFdecoder}$, which implements several encoder-decoder models to reconstruct PDFs with high fidelity and use this tool to explore strengths and pitfalls of neural-network approaches to PDF parametrization. We additionally dissect patterns of learned correlations between encoded Mellin moments and reconstructed PDFs which suggest opportunities for further improvements to ML-based approaches to PDF parametrizations and uncertainty quantification.
1404.5768
Vladimir Grichine
V.M. Grichine
Nucleon elastic scattering in quark-diquark representation with springy Pomeron
5 pages
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A model for elastic scattering of nucleons (and anti-nucleons) based on the quark-diquark representation of the nucleon with springy Pomeron, providing increased real part of the scattering amplitude, is developed. The model predictions are compared with experimental data for the differential elastic cross-sections of nucleons in the energy range from few GeV up to 7 TeV using available databases.
[ { "created": "Wed, 23 Apr 2014 10:03:40 GMT", "version": "v1" } ]
2014-04-24
[ [ "Grichine", "V. M.", "" ] ]
A model for elastic scattering of nucleons (and anti-nucleons) based on the quark-diquark representation of the nucleon with springy Pomeron, providing increased real part of the scattering amplitude, is developed. The model predictions are compared with experimental data for the differential elastic cross-sections of nucleons in the energy range from few GeV up to 7 TeV using available databases.
0810.4906
Nita Sinha
Nita Sinha
Determining the Neutral D Mixing Parameters
5 pages, talk presented at the International Conference on High Energy Physics, ICHEP08, Philadelphia, 2008
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Evidence for mixing in the neutral D meson system has recently been reported. Assuming negligible CP violation, non-vanishing width and mass differences between the two neutral D mass eigenstates has been found. Theoretical predictions of these are rather difficult, obscuring detection of New Physics contributions. However, the observation of CP violation in the D system would be a good signal of New Physics. We briefly describe the formalism that describes the neutral D decay and mixing, and present a method to determine all the mixing parameters accurately allowing for arbitrary CP violation.
[ { "created": "Mon, 27 Oct 2008 19:16:28 GMT", "version": "v1" } ]
2008-10-28
[ [ "Sinha", "Nita", "" ] ]
Evidence for mixing in the neutral D meson system has recently been reported. Assuming negligible CP violation, non-vanishing width and mass differences between the two neutral D mass eigenstates has been found. Theoretical predictions of these are rather difficult, obscuring detection of New Physics contributions. However, the observation of CP violation in the D system would be a good signal of New Physics. We briefly describe the formalism that describes the neutral D decay and mixing, and present a method to determine all the mixing parameters accurately allowing for arbitrary CP violation.
1903.10486
Suman Kumbhakar
Ashutosh Kumar Alok, Dinesh Kumar, Suman Kumbhakar, S Uma Sankar
Solutions to $R_D$-$R_{D^*}$ in light of Belle 2019 data
6 pages, 2 figures, 4 tables, title changed
Nucl. Phys. B 953 (2020) 114957
10.1016/j.nuclphysb.2020.114957
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Earlier this year, the Belle collaboration presented their new measurements of $R_D$ and $R_{D^*}$ using a new method. These measurements are consistent with the Standard Model predictions, whereas the global averages of the earlier measurements had a $4.1\sigma$ discrepancy. With the inclusion of the new data in the global averages, the discrepancy comes down to $3.1\sigma$. In this work, we study the study the new physics solutions to the $R_D$-$R_{D^*}$ anomaly allowed by the reduction in the discrepancy. Among the four fermion operators, which arise through a single particle exchange, only the $(V-A)$ operator solution survives. We found three additional solutions with two dis-similar operators. The branching ratio of $B_c\rightarrow \tau\,\bar{\nu}$ is powerful discriminant between these four allowed solutions.
[ { "created": "Mon, 25 Mar 2019 17:32:13 GMT", "version": "v1" }, { "created": "Sun, 25 Aug 2019 05:58:12 GMT", "version": "v2" }, { "created": "Thu, 12 Dec 2019 05:24:57 GMT", "version": "v3" } ]
2020-02-17
[ [ "Alok", "Ashutosh Kumar", "" ], [ "Kumar", "Dinesh", "" ], [ "Kumbhakar", "Suman", "" ], [ "Sankar", "S Uma", "" ] ]
Earlier this year, the Belle collaboration presented their new measurements of $R_D$ and $R_{D^*}$ using a new method. These measurements are consistent with the Standard Model predictions, whereas the global averages of the earlier measurements had a $4.1\sigma$ discrepancy. With the inclusion of the new data in the global averages, the discrepancy comes down to $3.1\sigma$. In this work, we study the study the new physics solutions to the $R_D$-$R_{D^*}$ anomaly allowed by the reduction in the discrepancy. Among the four fermion operators, which arise through a single particle exchange, only the $(V-A)$ operator solution survives. We found three additional solutions with two dis-similar operators. The branching ratio of $B_c\rightarrow \tau\,\bar{\nu}$ is powerful discriminant between these four allowed solutions.
hep-ph/9707248
Michelangelo Mangano
M.L. Mangano and S. R. Slabospitsky
The Contribution of Bc Mesons to the Search for B->tau nu Decays at LEP
8 pages, Latex, epsfig, 1 figure
Phys.Lett.B410:299-303,1997
10.1016/S0370-2693(97)00953-2
CERN-TH/97-150
hep-ph hep-ex
null
We study the contribution of B_c mesons to the search for B->tau nu decays. We find that at LEP the contributions from B_u and B_c mesons can be comparable. This observation can have a relevant impact on the extraction of constraints on new physics (such as charged-Higgs contributions) from current LEP limits on B->tau nu final states. Inclusion of the B_c contribution can reduce the current L3 limit on Tan(beta)/M_H from 0.38/GeV (90%CL) down to 0.27/GeV (90%CL).
[ { "created": "Fri, 4 Jul 1997 14:45:31 GMT", "version": "v1" } ]
2008-11-26
[ [ "Mangano", "M. L.", "" ], [ "Slabospitsky", "S. R.", "" ] ]
We study the contribution of B_c mesons to the search for B->tau nu decays. We find that at LEP the contributions from B_u and B_c mesons can be comparable. This observation can have a relevant impact on the extraction of constraints on new physics (such as charged-Higgs contributions) from current LEP limits on B->tau nu final states. Inclusion of the B_c contribution can reduce the current L3 limit on Tan(beta)/M_H from 0.38/GeV (90%CL) down to 0.27/GeV (90%CL).
hep-ph/9910492
Gavin Salam
Gavin P. Salam
An introduction to leading and next-to-leading BFKL
27 pages; presented at the Cracow School of Theoretical Physics, XXXIX Course, May 1999
Acta Phys.Polon.B30:3679-3705,1999
null
Bicocca-FT-99-35
hep-ph
null
Of late, the field of BFKL physics has been the subject of significant developments. The calculation of the NLL terms was recently completed, and they turned out to be very large. Techniques have been proposed to resum these corrections. These lectures provide an introduction to the BFKL equation and some of the recent developments, using DGLAP evolution as the starting point.
[ { "created": "Tue, 26 Oct 1999 15:58:16 GMT", "version": "v1" } ]
2014-11-17
[ [ "Salam", "Gavin P.", "" ] ]
Of late, the field of BFKL physics has been the subject of significant developments. The calculation of the NLL terms was recently completed, and they turned out to be very large. Techniques have been proposed to resum these corrections. These lectures provide an introduction to the BFKL equation and some of the recent developments, using DGLAP evolution as the starting point.
hep-ph/9909355
Douglas W. McKay
Loretta M. Johnson, Douglas W. McKay
Revising Neutrino Oscillation Parameter Space With Direct Flavor-Changing Interactions
16 pages, 10 figures
Phys.Rev. D61 (2000) 113007
10.1103/PhysRevD.61.113007
null
hep-ph
null
We formulate direct, neutrino flavor-changing interactions in a framework that fits smoothly with the parameterization of two-and three-state mixing of massive neutrino states. We show that even small direct interaction strengths could have important consequences for the interpretation of currently running and proposed oscillation experiments. The oscillation amplitude and the borders of the allowed regions in two-and three-flavor mixing parameter space can be sensitieve to the presence of direct interactions when the transition probability is small. We use extensively the high sensitivity of the NOMAD experiment to illustrate potentially large effects from small, direct flavor violation. In the purely leptonic sector, we find that the clean muon neutrino and electron neutrino beams from a muon collider could provide the sharpest tests of direct flavor violation.
[ { "created": "Tue, 14 Sep 1999 04:57:18 GMT", "version": "v1" } ]
2009-10-31
[ [ "Johnson", "Loretta M.", "" ], [ "McKay", "Douglas W.", "" ] ]
We formulate direct, neutrino flavor-changing interactions in a framework that fits smoothly with the parameterization of two-and three-state mixing of massive neutrino states. We show that even small direct interaction strengths could have important consequences for the interpretation of currently running and proposed oscillation experiments. The oscillation amplitude and the borders of the allowed regions in two-and three-flavor mixing parameter space can be sensitieve to the presence of direct interactions when the transition probability is small. We use extensively the high sensitivity of the NOMAD experiment to illustrate potentially large effects from small, direct flavor violation. In the purely leptonic sector, we find that the clean muon neutrino and electron neutrino beams from a muon collider could provide the sharpest tests of direct flavor violation.
1111.4904
Francesco Coradeschi
Francesco Bernardini, Francesco Coradeschi and Daniele Dominici
Effective chiral Lagrangians for new vector bosons to O(p^4) order
PDF-LaTeX with 11 figures, 8 .mf files for Feynman diagrams. Uses feynmf package and h-physrev5 bibliography style
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
If the SM Higgs boson does not exist, electroweak symmetry breaking may be realized via a strong interaction with a typical scale Lambda > 1 TeV. Resonances from the strong sector may help to unitarize WW scattering, which becomes strong in the absence of an Higgs field, and could be detected at the LHC. In this paper we describe such a scenario, in the minimal case in which only one new vector resonance is present, via a chiral SU(2) x SU(2)/SU(2) lagrangian also including all possible invariant terms up to O(p^4) order (assuming a parity symmetry in the strong sector). The O(p^4) invariants are not usually taken into account in similar studies in the literature; however, they have been shown to be potentially important, at least, to reconcile this kind of scheme with electroweak precision tests. Here we use the O(p^4) lagrangian to study the scattering amplitudes for the pi pi sector, investigating the partial wave unitarity properties of the model and its cut-off energy scale. We obtain constraints on the parameter space and compare our result to the one obtained with just the O(p^2) lagrangian, finding that the contribution of the new operators is indeed significant.
[ { "created": "Mon, 21 Nov 2011 15:47:55 GMT", "version": "v1" } ]
2011-11-22
[ [ "Bernardini", "Francesco", "" ], [ "Coradeschi", "Francesco", "" ], [ "Dominici", "Daniele", "" ] ]
If the SM Higgs boson does not exist, electroweak symmetry breaking may be realized via a strong interaction with a typical scale Lambda > 1 TeV. Resonances from the strong sector may help to unitarize WW scattering, which becomes strong in the absence of an Higgs field, and could be detected at the LHC. In this paper we describe such a scenario, in the minimal case in which only one new vector resonance is present, via a chiral SU(2) x SU(2)/SU(2) lagrangian also including all possible invariant terms up to O(p^4) order (assuming a parity symmetry in the strong sector). The O(p^4) invariants are not usually taken into account in similar studies in the literature; however, they have been shown to be potentially important, at least, to reconcile this kind of scheme with electroweak precision tests. Here we use the O(p^4) lagrangian to study the scattering amplitudes for the pi pi sector, investigating the partial wave unitarity properties of the model and its cut-off energy scale. We obtain constraints on the parameter space and compare our result to the one obtained with just the O(p^2) lagrangian, finding that the contribution of the new operators is indeed significant.
0904.2789
Surjeet Rajendran
Asimina Arvanitaki, Savas Dimopoulos, Sergei Dubovsky, Peter W. Graham, Roni Harnik, Surjeet Rajendran
Decaying Dark Matter as a Probe of Unification and TeV Spectroscopy
7 pages, 5 figures, 1 table, New Refs added
Phys.Rev.D80:055011,2009
10.1103/PhysRevD.80.055011
null
hep-ph astro-ph.HE hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In supersymmetric unified theories the dark matter particle can decay, just like the proton, through grand unified interactions with a lifetime of order of 10^{26} sec. Its decay products can be detected by several experiments -- including Fermi, HESS, PAMELA, ATIC, and IceCube -- opening our first direct window to physics at the TeV scale and simultaneously at the unification scale 10^{16} GeV. We consider possibilities for explaining the electron/positron spectra observed by HESS, PAMELA, and ATIC, and the resulting predictions for the gamma-ray, electron/positron, and neutrino spectra as will be measured, for example, by Fermi and IceCube. The discovery of an isotropic, hard gamma ray spectral feature at Fermi would be strong evidence for dark matter and would disfavor astrophysical sources such as pulsars. Substructure in the cosmic ray spectra probes the spectroscopy of new TeV-mass particles. For example, a preponderance of electrons in the final state can result from the lightness of selectrons relative to squarks. Decaying dark matter acts as a sparticle injector with an energy reach potentially higher than the LHC. The resulting cosmic ray flux depends only on the values of the weak and unification scales.
[ { "created": "Fri, 17 Apr 2009 22:39:09 GMT", "version": "v1" }, { "created": "Wed, 27 May 2009 20:30:40 GMT", "version": "v2" } ]
2009-09-24
[ [ "Arvanitaki", "Asimina", "" ], [ "Dimopoulos", "Savas", "" ], [ "Dubovsky", "Sergei", "" ], [ "Graham", "Peter W.", "" ], [ "Harnik", "Roni", "" ], [ "Rajendran", "Surjeet", "" ] ]
In supersymmetric unified theories the dark matter particle can decay, just like the proton, through grand unified interactions with a lifetime of order of 10^{26} sec. Its decay products can be detected by several experiments -- including Fermi, HESS, PAMELA, ATIC, and IceCube -- opening our first direct window to physics at the TeV scale and simultaneously at the unification scale 10^{16} GeV. We consider possibilities for explaining the electron/positron spectra observed by HESS, PAMELA, and ATIC, and the resulting predictions for the gamma-ray, electron/positron, and neutrino spectra as will be measured, for example, by Fermi and IceCube. The discovery of an isotropic, hard gamma ray spectral feature at Fermi would be strong evidence for dark matter and would disfavor astrophysical sources such as pulsars. Substructure in the cosmic ray spectra probes the spectroscopy of new TeV-mass particles. For example, a preponderance of electrons in the final state can result from the lightness of selectrons relative to squarks. Decaying dark matter acts as a sparticle injector with an energy reach potentially higher than the LHC. The resulting cosmic ray flux depends only on the values of the weak and unification scales.
2003.07670
Er-Liang Cui
Rui-Rui Dong, Niu Su, Hua-Xing Chen, Er-Liang Cui, and Zhi-Yong Zhou
QCD sum rule studies on the $s s \bar s \bar s$ tetraquark states of $J^{PC} = 0^{-+}$
8 pages, 6 figures, suggestions and comments are welcome
null
10.1140/epjc/s10052-020-8340-9
null
hep-ph hep-ex hep-lat
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We apply the method of QCD sum rules to study the $s s \bar s \bar s$ tetraquark states of $J^{PC} = 0^{-+}$. We construct all the relevant $s s \bar s \bar s$ tetraquark currents, and find that there are only two independent ones. We use them to further construct two weakly-correlated mixed currents. One of them leads to reliable QCD sum rule results and the mass is extracted to be $2.51^{+0.15}_{-0.12}$ GeV, suggesting that the $X(2370)$ or the $X(2500)$ can be explained as the $ss\bar s\bar s$ tetraquark state of $J^{PC} = 0^{-+}$. To verify this interpretation, we propose to further study the $\pi\pi/K \bar K$ invariant mass spectra of the $J/\psi \to \gamma \pi \pi \eta^\prime/\gamma K \bar K \eta^\prime$ decays in BESIII to examine whether there exists the $f_0(980)$ resonance.
[ { "created": "Tue, 17 Mar 2020 12:45:56 GMT", "version": "v1" }, { "created": "Wed, 19 Aug 2020 01:49:22 GMT", "version": "v2" } ]
2021-02-03
[ [ "Dong", "Rui-Rui", "" ], [ "Su", "Niu", "" ], [ "Chen", "Hua-Xing", "" ], [ "Cui", "Er-Liang", "" ], [ "Zhou", "Zhi-Yong", "" ] ]
We apply the method of QCD sum rules to study the $s s \bar s \bar s$ tetraquark states of $J^{PC} = 0^{-+}$. We construct all the relevant $s s \bar s \bar s$ tetraquark currents, and find that there are only two independent ones. We use them to further construct two weakly-correlated mixed currents. One of them leads to reliable QCD sum rule results and the mass is extracted to be $2.51^{+0.15}_{-0.12}$ GeV, suggesting that the $X(2370)$ or the $X(2500)$ can be explained as the $ss\bar s\bar s$ tetraquark state of $J^{PC} = 0^{-+}$. To verify this interpretation, we propose to further study the $\pi\pi/K \bar K$ invariant mass spectra of the $J/\psi \to \gamma \pi \pi \eta^\prime/\gamma K \bar K \eta^\prime$ decays in BESIII to examine whether there exists the $f_0(980)$ resonance.
2109.06571
Carlota Andres
Carlota Andres, Liliana Apolinario, and Fabio Dominguez
Full solution of the medium-induced radiation spectrum
Proceedings of Hard Probes 2020
PoS HardProbes2020 (2021) 125
10.22323/1.387.0125
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
New measurements of jet quenching observables at RHIC and at the LHC, such as jet substructure observables, demand an increased precision in the theory calculations describing medium-induced radiation of gluons. Closed expressions for the gluon spectrum including a full resummation of multiple scatterings have been known for the past 20 years. Still they have only been evaluated in specific limits either taking a few terms in an opacity expansion or by employing a Gaussian approximation for the interaction potential -- which misses essential physical effects. We present here a new flexible method to compute the full spectrum for a realistic interaction potential, thus allowing us for the first time to properly quantify the effect of the all-order resummation of multiple scatterings. This new approach paves the way for precision phenomenological studies including multiple scattering effects such as coherence phenomena.
[ { "created": "Tue, 14 Sep 2021 10:38:40 GMT", "version": "v1" } ]
2021-09-15
[ [ "Andres", "Carlota", "" ], [ "Apolinario", "Liliana", "" ], [ "Dominguez", "Fabio", "" ] ]
New measurements of jet quenching observables at RHIC and at the LHC, such as jet substructure observables, demand an increased precision in the theory calculations describing medium-induced radiation of gluons. Closed expressions for the gluon spectrum including a full resummation of multiple scatterings have been known for the past 20 years. Still they have only been evaluated in specific limits either taking a few terms in an opacity expansion or by employing a Gaussian approximation for the interaction potential -- which misses essential physical effects. We present here a new flexible method to compute the full spectrum for a realistic interaction potential, thus allowing us for the first time to properly quantify the effect of the all-order resummation of multiple scatterings. This new approach paves the way for precision phenomenological studies including multiple scattering effects such as coherence phenomena.
hep-ph/9812463
Martin Hirsch
M. Hirsch and J.W.F. Valle
Neutrinoless double beta decay in Supersymmetry with bilinear R-parity breaking
revised after referee report, new figure 5, some typos corrected, accepted for publication in Nucl.Phys.B
Nucl.Phys.B557:60-78,1999
10.1016/S0550-3213(99)00368-5
FTUV/98-100, IFIC/98-101
hep-ph
null
We reanalyze the contributions to neutrinoless double beta ($\znbb$) decay from supersymmetry with explicit breaking of R-parity. Although we keep both bilinear and trilinear terms, our emphasis is put on bilinear R-parity breaking terms, because these mimic more closely the models where the breaking of R-parity is spontaneous. Comparing the relevant Feynman diagrams we conclude that the usual mass mechanism of double beta decay is the dominant one. From the non-observation of $\znbb$ decay we set limits on the bilinear R-parity breaking parameters of typically a (few) 100 $keV$. Despite such stringent bounds, we stress that the magnitude of R-parity violating phenomena that can be expected at accelerator experiments can be very large, since they involve mainly the third generation, while $\znbb$ decay constrains only the first generation couplings.
[ { "created": "Mon, 21 Dec 1998 18:55:40 GMT", "version": "v1" }, { "created": "Wed, 20 Jan 1999 19:28:45 GMT", "version": "v2" }, { "created": "Tue, 8 Jun 1999 13:39:10 GMT", "version": "v3" } ]
2009-09-17
[ [ "Hirsch", "M.", "" ], [ "Valle", "J. W. F.", "" ] ]
We reanalyze the contributions to neutrinoless double beta ($\znbb$) decay from supersymmetry with explicit breaking of R-parity. Although we keep both bilinear and trilinear terms, our emphasis is put on bilinear R-parity breaking terms, because these mimic more closely the models where the breaking of R-parity is spontaneous. Comparing the relevant Feynman diagrams we conclude that the usual mass mechanism of double beta decay is the dominant one. From the non-observation of $\znbb$ decay we set limits on the bilinear R-parity breaking parameters of typically a (few) 100 $keV$. Despite such stringent bounds, we stress that the magnitude of R-parity violating phenomena that can be expected at accelerator experiments can be very large, since they involve mainly the third generation, while $\znbb$ decay constrains only the first generation couplings.
hep-ph/0601132
Nestor Armesto
N. Armesto and J. G. Milhano
On correlations and discreteness in non-linear QCD evolution
20 pages, LaTeX, 18 eps figures included using epsfig; changes in v3: new kind of averaging added, 5 new plots, discussions and conclusions extended, final version
Phys.Rev.D73:114003,2006
10.1103/PhysRevD.73.114003
null
hep-ph
null
We consider modifications of the standard non-linear QCD evolution in an attempt to account for some of the missing ingredients discussed recently, such as correlations, discreteness in gluon emission and Pomeron loops. The evolution is numerically performed using the Balitsky-Kovchegov equation on individual configurations defined by a given initial value of the saturation scale, for reduced rapidities $y=(\alpha_s N_c/\pi) Y<10$. We consider the effects of averaging over configurations as a way to implement correlations, using three types of Gaussian averaging around a mean saturation scale. Further, we heuristically mimic discreteness in gluon emission by considering a modified evolution in which the tails of the gluon distributions are cut-off. The approach to scaling and the behavior of the saturation scale with rapidity in these modified evolutions are studied and compared with the standard mean-field results. For the large but finite values of rapidity explored, no strong quantitative difference in scaling for transverse momenta around the saturation scale is observed. At larger transverse momenta, the influence of the modifications in the evolution seems most noticeable in the first steps of the evolution. No influence on the rapidity behavior of the saturation scale due to the averaging procedure is found. In the cut-off evolution the rapidity evolution of the saturation scale is slowed down and strongly depends on the value of the cut-off. Our results stress the need to go beyond simple modifications of evolution by developing proper theoretical tools that implement such recently discussed ingredients.
[ { "created": "Tue, 17 Jan 2006 15:50:22 GMT", "version": "v1" }, { "created": "Wed, 25 Jan 2006 15:38:06 GMT", "version": "v2" }, { "created": "Tue, 16 May 2006 12:11:25 GMT", "version": "v3" } ]
2008-11-26
[ [ "Armesto", "N.", "" ], [ "Milhano", "J. G.", "" ] ]
We consider modifications of the standard non-linear QCD evolution in an attempt to account for some of the missing ingredients discussed recently, such as correlations, discreteness in gluon emission and Pomeron loops. The evolution is numerically performed using the Balitsky-Kovchegov equation on individual configurations defined by a given initial value of the saturation scale, for reduced rapidities $y=(\alpha_s N_c/\pi) Y<10$. We consider the effects of averaging over configurations as a way to implement correlations, using three types of Gaussian averaging around a mean saturation scale. Further, we heuristically mimic discreteness in gluon emission by considering a modified evolution in which the tails of the gluon distributions are cut-off. The approach to scaling and the behavior of the saturation scale with rapidity in these modified evolutions are studied and compared with the standard mean-field results. For the large but finite values of rapidity explored, no strong quantitative difference in scaling for transverse momenta around the saturation scale is observed. At larger transverse momenta, the influence of the modifications in the evolution seems most noticeable in the first steps of the evolution. No influence on the rapidity behavior of the saturation scale due to the averaging procedure is found. In the cut-off evolution the rapidity evolution of the saturation scale is slowed down and strongly depends on the value of the cut-off. Our results stress the need to go beyond simple modifications of evolution by developing proper theoretical tools that implement such recently discussed ingredients.
1607.00244
Debasish Borah
Debasish Borah
Light Sterile Neutrino and Dark Matter in Left-Right Symmetric Models Without Higgs Bidoublet
Version 2: Minor changes, to appear in Phys. Rev. D
Phys. Rev. D 94, 075024 (2016)
10.1103/PhysRevD.94.075024
null
hep-ph astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a class of left-right symmetric models where Dirac as well as Majorana mass terms of neutrinos can arise at one-loop level in a scotogenic fashion: with dark matter particles going inside the loop. We show the possibility of naturally light right handed neutrinos that can have interesting implications at neutrinoless double beta decay experiments as well as cosmology. Apart from a stable dark matter candidate stabilised by a remnant $Z_2$ symmetry, one can also have a long lived keV sterile neutrino dark matter in these models. This class of models can have very different collider signatures compared to the conventional left-right models.
[ { "created": "Fri, 1 Jul 2016 13:47:43 GMT", "version": "v1" }, { "created": "Tue, 18 Oct 2016 16:04:07 GMT", "version": "v2" } ]
2016-11-09
[ [ "Borah", "Debasish", "" ] ]
We present a class of left-right symmetric models where Dirac as well as Majorana mass terms of neutrinos can arise at one-loop level in a scotogenic fashion: with dark matter particles going inside the loop. We show the possibility of naturally light right handed neutrinos that can have interesting implications at neutrinoless double beta decay experiments as well as cosmology. Apart from a stable dark matter candidate stabilised by a remnant $Z_2$ symmetry, one can also have a long lived keV sterile neutrino dark matter in these models. This class of models can have very different collider signatures compared to the conventional left-right models.
hep-ph/0205032
Xing ZhiZhong
Zhi-zhong Xing
A Full Determination of the Neutrino Mass Spectrum from Two-zero Textures of the Neutrino Mass Matrix
LaTex 8 pages. Modifications made. References added. Acknowledgments changed
Phys.Lett. B539 (2002) 85-90
10.1016/S0370-2693(02)02062-2
BIHEP-TH-2002-25
hep-ph
null
We show that it is possible to fully determine the neutrino mass spectrum from two-zero textures of the neutrino mass matrix. As a consequence, definite predictions can be obtained for the neutrinoless double beta decay.
[ { "created": "Fri, 3 May 2002 01:29:26 GMT", "version": "v1" }, { "created": "Wed, 26 Jun 2002 06:55:00 GMT", "version": "v2" } ]
2015-06-25
[ [ "Xing", "Zhi-zhong", "" ] ]
We show that it is possible to fully determine the neutrino mass spectrum from two-zero textures of the neutrino mass matrix. As a consequence, definite predictions can be obtained for the neutrinoless double beta decay.
1002.3628
Klaus Rabbertz
Klaus Rabbertz
QCD and Electroweak Physics at LHC
10 pages, 14 figures; Contribution to the 9th International Symposium on Radiative Corrections (RADCOR 2009), October 25-30 2009, Ascona, Switzerland
PoS(RADCOR2009)016
null
CMS CR-2010/023
hep-ph
http://creativecommons.org/licenses/by-nc-sa/3.0/
First LHC data have been collected and collisions at a center-of-mass energy of 7 TeV are anticipated for the next months. The commissioning of the detectors and the re-establishment of the Standard Model in the new energy regime will be the main tasks for the experimental collaborations in the year to come. This report summarizes the measurement plans and performance expectations of the ATLAS and CMS experiments for a selected number of QCD and electroweak analyses with an emphasis on the early data taking phase. Some longer term prospects are pointed out.
[ { "created": "Thu, 18 Feb 2010 22:12:45 GMT", "version": "v1" } ]
2010-02-22
[ [ "Rabbertz", "Klaus", "" ] ]
First LHC data have been collected and collisions at a center-of-mass energy of 7 TeV are anticipated for the next months. The commissioning of the detectors and the re-establishment of the Standard Model in the new energy regime will be the main tasks for the experimental collaborations in the year to come. This report summarizes the measurement plans and performance expectations of the ATLAS and CMS experiments for a selected number of QCD and electroweak analyses with an emphasis on the early data taking phase. Some longer term prospects are pointed out.
hep-ph/9308322
Stefano Forte
Richard Ball and Stefano Forte
Anomalous Evolution of the Gottfried Sum
plain TeX with the harvmac macropackage, 35 pages (harvmac b mode), 11 figures included in a separate uuencoded postscript file, OUTP-93-18P, DFTT 9/93
Nucl.Phys.B425:516-552,1994
10.1016/0550-3213(94)90286-0
null
hep-ph
null
We discuss nonperturbative QCD evolution of nonsinglet nucleon structure functions, with particular application to the Gottfried sum. We show that the coupling of the quark partons to bound state mesons leads to nonperturbative contributions to the Altarelli--Parisi equations which, due to the axial anomaly, result in a strong scale dependence of nonsinglet structure functions for values of $Q^2$ around the nucleon mass scale. We compute specifically the evolution of the first moment of the quark distribution, and find that it is sufficient to explain recent experimental data which indicate a violation of the Gottfried sum rule.
[ { "created": "Mon, 23 Aug 1993 17:57:34 GMT", "version": "v1" } ]
2014-11-17
[ [ "Ball", "Richard", "" ], [ "Forte", "Stefano", "" ] ]
We discuss nonperturbative QCD evolution of nonsinglet nucleon structure functions, with particular application to the Gottfried sum. We show that the coupling of the quark partons to bound state mesons leads to nonperturbative contributions to the Altarelli--Parisi equations which, due to the axial anomaly, result in a strong scale dependence of nonsinglet structure functions for values of $Q^2$ around the nucleon mass scale. We compute specifically the evolution of the first moment of the quark distribution, and find that it is sufficient to explain recent experimental data which indicate a violation of the Gottfried sum rule.
2310.09380
Klaus Werner
K. Werner
Parallel scattering, saturation, and generalized Abramovskii-Gribov-Kancheli (AGK) theorem in the EPOS4 framework, with applications for heavy-ion collisions at $\sqrt{s_{NN}}$ of 5.02 TeV and 200 GeV
53 pages, 73 figures
null
null
null
hep-ph nucl-th
http://creativecommons.org/licenses/by/4.0/
Ultrarelativistic heavy-ion collisions will first realize many nucleon-nucleon scatterings, happening instantaneously and therefore necessarily in parallel, due to the short collision time. An appropriate quantum mechanical tool to treat that problem is S-matrix theory, and it has been known for a long time how to derive a simple geometric probabilistic picture, still widely used, and here the Abramovskii-Gribov-Kancheli (AGK) theorem plays a crucial role. All this is done in a scenario where energy conservation is not taken care of, but this is needed, in particular for Monte Carlo simulations. When introducing energy-momentum sharing properly, the AGK theorem does not apply anymore, nor do simple geometric concepts such as binary scaling. I will discuss this (very serious) problem, and how it can be solved, in the EPOS4 framework. When connecting the multiple Pomeron approach (for parallel scatterings) and perturbative QCD, one is actually forced to implement in a very particular way saturation scales, in order to get an approach free of contradictions. One recovers a generalized AGK theorem (gAGK), valid at large $p_{t}$ (larger than the relevant saturation scales). I discuss how gAGK is related to factorization (in proton-proton scatterings) and binary scaling (in heavy-ion collisions). I will show some applications, using this new approach as an initial condition for hydrodynamical evolutions, for heavy-ion collisions at $\sqrt{s_{NN}}$ of 5.02 TeV and 200 GeV, to get some idea about the energy dependence.
[ { "created": "Fri, 13 Oct 2023 19:59:11 GMT", "version": "v1" }, { "created": "Mon, 1 Apr 2024 17:10:14 GMT", "version": "v2" } ]
2024-04-02
[ [ "Werner", "K.", "" ] ]
Ultrarelativistic heavy-ion collisions will first realize many nucleon-nucleon scatterings, happening instantaneously and therefore necessarily in parallel, due to the short collision time. An appropriate quantum mechanical tool to treat that problem is S-matrix theory, and it has been known for a long time how to derive a simple geometric probabilistic picture, still widely used, and here the Abramovskii-Gribov-Kancheli (AGK) theorem plays a crucial role. All this is done in a scenario where energy conservation is not taken care of, but this is needed, in particular for Monte Carlo simulations. When introducing energy-momentum sharing properly, the AGK theorem does not apply anymore, nor do simple geometric concepts such as binary scaling. I will discuss this (very serious) problem, and how it can be solved, in the EPOS4 framework. When connecting the multiple Pomeron approach (for parallel scatterings) and perturbative QCD, one is actually forced to implement in a very particular way saturation scales, in order to get an approach free of contradictions. One recovers a generalized AGK theorem (gAGK), valid at large $p_{t}$ (larger than the relevant saturation scales). I discuss how gAGK is related to factorization (in proton-proton scatterings) and binary scaling (in heavy-ion collisions). I will show some applications, using this new approach as an initial condition for hydrodynamical evolutions, for heavy-ion collisions at $\sqrt{s_{NN}}$ of 5.02 TeV and 200 GeV, to get some idea about the energy dependence.
1404.2581
Alberto Tonero Dr.
Alberto Tonero and Rogerio Rosenfeld
Dipole-induced anomalous top quark couplings at the LHC
9 pages, 1 figure, 1 table; references added. Version accepted for publication in PRD
null
10.1103/PhysRevD.90.017701
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider direct bounds on the coefficients of higher dimensional top quark dipole operators from their contributions to anomalous top couplings that affect some related processes at the LHC. Several observables are studied. In particular, we incorporate for the first time in this type of analysis the recently measured associated $t \bar{t} V$ production, which is currently the only measured direct observable sensitive to the dipole operator involving the hypercharge field. We perform a Bayesian analysis to derive the $1(2)\sigma$ confidence level (CL) intervals on these coefficients.
[ { "created": "Wed, 9 Apr 2014 19:21:21 GMT", "version": "v1" }, { "created": "Wed, 2 Jul 2014 17:00:11 GMT", "version": "v2" } ]
2015-06-19
[ [ "Tonero", "Alberto", "" ], [ "Rosenfeld", "Rogerio", "" ] ]
We consider direct bounds on the coefficients of higher dimensional top quark dipole operators from their contributions to anomalous top couplings that affect some related processes at the LHC. Several observables are studied. In particular, we incorporate for the first time in this type of analysis the recently measured associated $t \bar{t} V$ production, which is currently the only measured direct observable sensitive to the dipole operator involving the hypercharge field. We perform a Bayesian analysis to derive the $1(2)\sigma$ confidence level (CL) intervals on these coefficients.
1803.09762
Camilo Garcia-Cely
Xiaoyong Chu, Camilo Garcia-Cely
Core formation from self-heating dark matter
Published version. 9 pages, 7 figures
null
10.1088/1475-7516/2018/07/013
null
hep-ph astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Cosmological simulations of the $\Lambda$CDM model suggest that the dark matter halos of dwarf galaxies are denser in their center than what observational data of such galaxies imply. In this letter, we propose a novel solution to this problem by invoking a certain class of dark matter self-heating processes. As we will argue, such processes lead to the formation of dark matter cores at late times by considerably reducing the inner mass density of dwarf-sized halos. For deriving concrete results, we focus on semi-annihilating dark matter scenarios and model the inner region of dark matter halos as a gravothermal fluid. An important aspect of this new solution is that the semi-annihilation effects are much more prominent in dwarf-sized halos than in the more massive halos that host galaxies and clusters, even if the corresponding cross sections are the same. Furthermore, the preferred parameter space for solving the small-scale problem suggests a thermal dark matter candidate with a mass below the GeV scale, which can be probed in dark matter direct and indirect detection experiments.
[ { "created": "Mon, 26 Mar 2018 18:00:08 GMT", "version": "v1" }, { "created": "Thu, 5 Jul 2018 16:45:50 GMT", "version": "v2" } ]
2018-07-18
[ [ "Chu", "Xiaoyong", "" ], [ "Garcia-Cely", "Camilo", "" ] ]
Cosmological simulations of the $\Lambda$CDM model suggest that the dark matter halos of dwarf galaxies are denser in their center than what observational data of such galaxies imply. In this letter, we propose a novel solution to this problem by invoking a certain class of dark matter self-heating processes. As we will argue, such processes lead to the formation of dark matter cores at late times by considerably reducing the inner mass density of dwarf-sized halos. For deriving concrete results, we focus on semi-annihilating dark matter scenarios and model the inner region of dark matter halos as a gravothermal fluid. An important aspect of this new solution is that the semi-annihilation effects are much more prominent in dwarf-sized halos than in the more massive halos that host galaxies and clusters, even if the corresponding cross sections are the same. Furthermore, the preferred parameter space for solving the small-scale problem suggests a thermal dark matter candidate with a mass below the GeV scale, which can be probed in dark matter direct and indirect detection experiments.
2005.04996
Xu-Dong Huang
Xu-Dong Huang, Xing-Gang Wu, Jun Zeng, Qing Yu, Xu-Chang Zheng and Shuai Xu
Determination of the top-quark $\overline{\rm MS}$ running mass via its perturbative relation to the on-shell mass with the help of principle of maximum conformality
8 pages, 2 figures
Phys. Rev. D 101, 114024 (2020)
10.1103/PhysRevD.101.114024
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In the paper, we study the properties of the top-quark $\overline{\rm MS}$ running mass computed from its on-shell mass by using both the four-loop $\overline{\rm MS}$-on-shell relation and the principle of maximum conformality (PMC) scale-setting approach. The PMC adopts the renormalization group equation to set the correct magnitude of the strong running coupling of the perturbative series, its prediction avoids the conventional renormalization scale ambiguity, and thus a more precise pQCD prediction can be achieved. After applying the PMC to the four-loop $\overline{\rm MS}$-on-shell relation and taking the top-quark on-shell mass $M_t=172.9\pm0.4$ GeV as an input, we obtain the renormalization scale-invariant $\overline{\rm MS}$ running mass at the scale $m_t$, e.g., $m_t(m_t)\simeq 162.6\pm 0.4$ GeV, in which the error is the squared average of those from $\Delta \alpha_s(M_Z)$, $\Delta M_t$, and the approximate error from the uncalculated five-loop terms predicted by using the Pad\'{e} approximation approach.
[ { "created": "Mon, 11 May 2020 11:06:37 GMT", "version": "v1" }, { "created": "Tue, 23 Jun 2020 01:35:38 GMT", "version": "v2" } ]
2020-06-25
[ [ "Huang", "Xu-Dong", "" ], [ "Wu", "Xing-Gang", "" ], [ "Zeng", "Jun", "" ], [ "Yu", "Qing", "" ], [ "Zheng", "Xu-Chang", "" ], [ "Xu", "Shuai", "" ] ]
In the paper, we study the properties of the top-quark $\overline{\rm MS}$ running mass computed from its on-shell mass by using both the four-loop $\overline{\rm MS}$-on-shell relation and the principle of maximum conformality (PMC) scale-setting approach. The PMC adopts the renormalization group equation to set the correct magnitude of the strong running coupling of the perturbative series, its prediction avoids the conventional renormalization scale ambiguity, and thus a more precise pQCD prediction can be achieved. After applying the PMC to the four-loop $\overline{\rm MS}$-on-shell relation and taking the top-quark on-shell mass $M_t=172.9\pm0.4$ GeV as an input, we obtain the renormalization scale-invariant $\overline{\rm MS}$ running mass at the scale $m_t$, e.g., $m_t(m_t)\simeq 162.6\pm 0.4$ GeV, in which the error is the squared average of those from $\Delta \alpha_s(M_Z)$, $\Delta M_t$, and the approximate error from the uncalculated five-loop terms predicted by using the Pad\'{e} approximation approach.
hep-ph/9706547
Alan R. White
Alan R. White
Excess Cross-Sections at the Electroweak Scale in the Sextet Quark ``Standard Model''
3 pages, with 1 ps figure in the text. Presented at the 5th International Workshop on Deep Inelastic Scattering and QCD, Chicago, Illinois, USA, April 14-18, 1997
null
10.1063/1.53604
ANL-HEP-CP-97-47
hep-ph
null
If dynamical electroweak symmetry breaking is due to a flavor doublet of color sextet quarks, enhanced electroweak scale QCD instanton interactions may produce a large top mass, raise the $\eta_6$ axion mass, and also explain the excesses in the DIS cross-section at HERA and jet cross-sections at the Tevatron.
[ { "created": "Mon, 30 Jun 1997 14:32:09 GMT", "version": "v1" } ]
2009-10-30
[ [ "White", "Alan R.", "" ] ]
If dynamical electroweak symmetry breaking is due to a flavor doublet of color sextet quarks, enhanced electroweak scale QCD instanton interactions may produce a large top mass, raise the $\eta_6$ axion mass, and also explain the excesses in the DIS cross-section at HERA and jet cross-sections at the Tevatron.
hep-ph/9508367
Charles A. Nelson
Charles A. Nelson, Minseob Kim, Daryl P. Nazareth, and Hui-Chun Yang
A General Treatment of Tau Semi-Leptonic Decays
Contributed paper to LP95, Beijing. Expanded version to be submitted to Phys. Rev. Before LaTeXing, cut off "by-line" at bottom
null
null
SUNY BING 7/1/95
hep-ph
null
The most general Lorentz invariant spin-correlation functions for $\tau ^{-}\rightarrow \rho ^{-}\nu ,a_1^{-}\nu ,K^{*-}\nu , \pi ^{-}\nu ,K^{-}\nu $ are expressed in terms of eight semi-leptonic parameters. They are physically defined in terms of tau-decay partial-width-intensities for polarized-final-states. The parameters are also expressed in terms of a ``$(V-A)\ +\ $additional chiral coupling'' structure in the ${J^{Charged}}_{Lepton}$ current, so as to bound the scales $\Lambda $\ for ``new physics'' such as arising from leptonic CP violation, tau weak magnetism, weak electricity, and/or second-class currents. The two tests for leptonic CP violation in $\tau \rightarrow \rho \nu \ $ decay are generalized to $\tau \rightarrow a_1\nu \ $ decay and to two additional tests if there are $\nu _R\ $ and $\bar \nu _L\ $ couplings.
[ { "created": "Thu, 24 Aug 1995 13:13:42 GMT", "version": "v1" } ]
2007-05-23
[ [ "Nelson", "Charles A.", "" ], [ "Kim", "Minseob", "" ], [ "Nazareth", "Daryl P.", "" ], [ "Yang", "Hui-Chun", "" ] ]
The most general Lorentz invariant spin-correlation functions for $\tau ^{-}\rightarrow \rho ^{-}\nu ,a_1^{-}\nu ,K^{*-}\nu , \pi ^{-}\nu ,K^{-}\nu $ are expressed in terms of eight semi-leptonic parameters. They are physically defined in terms of tau-decay partial-width-intensities for polarized-final-states. The parameters are also expressed in terms of a ``$(V-A)\ +\ $additional chiral coupling'' structure in the ${J^{Charged}}_{Lepton}$ current, so as to bound the scales $\Lambda $\ for ``new physics'' such as arising from leptonic CP violation, tau weak magnetism, weak electricity, and/or second-class currents. The two tests for leptonic CP violation in $\tau \rightarrow \rho \nu \ $ decay are generalized to $\tau \rightarrow a_1\nu \ $ decay and to two additional tests if there are $\nu _R\ $ and $\bar \nu _L\ $ couplings.
hep-ph/0001113
Dimitri Melikhov
D. Melikhov and B. Stech
Weak form factors for heavy meson decays: an update
revtex, 17 pages, improved version to be published in Phys. Rev. D. Results remain unchanged, but the presentation has been modified: now parametrizations for the form factors $A_0$, $A_1$, $A_2$ etc are given; and estimates of the weak and strong coupling constants of heavy mesons are added; few typoes corrected
Phys.Rev. D62 (2000) 014006
10.1103/PhysRevD.62.014006
Heidelberg preprint HD-THEP-00-01
hep-ph
null
We calculate the form factors for weak decays of $B_{(s)}$ and $D_{(s)}$ mesons to light pseudoscalar and vector mesons. To reveal the intimate connection between different decay modes and to be able to perform the calculations in the full physical $q^2$-region we use a relativistic dispersion approach based on the constituent quark picture. This approach gives the form factors as relativistic double spectral representations in terms of the wave functions of the initial and final mesons. The form factors have the correct analytic properties and satisfy general requirements of nonperturbative QCD in the heavy quark limit. The disadvantages of quark models related to ill-defined effective quark masses and not precisely known meson wave functions are reduced by fitting the quark model parameters to lattice QCD results for the $B\to \rho$ transition form factors at large momentum transfers and to the measured total $D\to (K,K^*)l\nu$ decay rates. This allows us to predict numerous form factors for all kinematically accessible $q^2$ values.
[ { "created": "Thu, 13 Jan 2000 15:03:41 GMT", "version": "v1" }, { "created": "Fri, 10 Mar 2000 13:28:59 GMT", "version": "v2" }, { "created": "Thu, 11 May 2000 09:13:28 GMT", "version": "v3" } ]
2009-10-31
[ [ "Melikhov", "D.", "" ], [ "Stech", "B.", "" ] ]
We calculate the form factors for weak decays of $B_{(s)}$ and $D_{(s)}$ mesons to light pseudoscalar and vector mesons. To reveal the intimate connection between different decay modes and to be able to perform the calculations in the full physical $q^2$-region we use a relativistic dispersion approach based on the constituent quark picture. This approach gives the form factors as relativistic double spectral representations in terms of the wave functions of the initial and final mesons. The form factors have the correct analytic properties and satisfy general requirements of nonperturbative QCD in the heavy quark limit. The disadvantages of quark models related to ill-defined effective quark masses and not precisely known meson wave functions are reduced by fitting the quark model parameters to lattice QCD results for the $B\to \rho$ transition form factors at large momentum transfers and to the measured total $D\to (K,K^*)l\nu$ decay rates. This allows us to predict numerous form factors for all kinematically accessible $q^2$ values.
hep-ph/0612003
Ho-Meoyng Choi
Chueng-Ryong Ji (North Carolina State Univ.), Bernard L. G. Bakker (Vrije Univ.) and Ho-Meoyng Choi (Kyungpook Nat'l Univ.)
New Developments in Treacherous Points of Light-Front Dynamics
5 pages, espcrc1.sty. proceedings of FB XVIII (August 2006, Brazil), to be published in Nucl. Phys. A
Nucl.Phys.A790:583-587,2007
10.1016/j.nuclphysa.2007.03.099
null
hep-ph
null
Light-front dynamics(LFD) plays an important role in hadron phenomenology. Last few years, however, it has been emphasized that treacherous points such as zero-mode contributions should be taken into account for successful LFD applications to hadron phenomenology. We discuss examples of treacherous points and present new progresses made last few years to handle them correctly.
[ { "created": "Fri, 1 Dec 2006 01:43:30 GMT", "version": "v1" } ]
2010-11-11
[ [ "Ji", "Chueng-Ryong", "", "North Carolina State Univ." ], [ "Bakker", "Bernard L. G.", "", "Vrije Univ." ], [ "Choi", "Ho-Meoyng", "", "Kyungpook Nat'l Univ." ] ]
Light-front dynamics(LFD) plays an important role in hadron phenomenology. Last few years, however, it has been emphasized that treacherous points such as zero-mode contributions should be taken into account for successful LFD applications to hadron phenomenology. We discuss examples of treacherous points and present new progresses made last few years to handle them correctly.
1909.10398
Mario Neves Junior
Y. M. P. Gomes, P. C. Malta and M. J. Neves
Testing Lorentz-symmetry violation via electroweak decays
12 pages, 2 figures, matches published version
Phys. Rev. D 101, 075001 (2020)
10.1103/PhysRevD.101.075001
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this work we introduce CPT-odd non-minimal Lorentz-symmetry violating couplings to the electroweak sector modifying the interaction between leptons and gauge bosons. The vertex rules allow us to calculate tree-level processes modified by the presence of the novel dimension-five operators. For definitiveness, we investigate the $W$ decay into a lepton-neutrino pair, the $Z$ decay into pairs of charged and neutral leptons, as well as the decay of the muon. By comparing the experimental measurements on these processes to our results we are able to bound several combinations of the background 4-vectors to be $\lesssim 10^{-4} \, \mbox{GeV}^{-1}$.
[ { "created": "Mon, 23 Sep 2019 14:42:01 GMT", "version": "v1" }, { "created": "Thu, 26 Dec 2019 23:08:07 GMT", "version": "v2" }, { "created": "Thu, 2 Apr 2020 18:02:57 GMT", "version": "v3" } ]
2020-04-08
[ [ "Gomes", "Y. M. P.", "" ], [ "Malta", "P. C.", "" ], [ "Neves", "M. J.", "" ] ]
In this work we introduce CPT-odd non-minimal Lorentz-symmetry violating couplings to the electroweak sector modifying the interaction between leptons and gauge bosons. The vertex rules allow us to calculate tree-level processes modified by the presence of the novel dimension-five operators. For definitiveness, we investigate the $W$ decay into a lepton-neutrino pair, the $Z$ decay into pairs of charged and neutral leptons, as well as the decay of the muon. By comparing the experimental measurements on these processes to our results we are able to bound several combinations of the background 4-vectors to be $\lesssim 10^{-4} \, \mbox{GeV}^{-1}$.
1310.3214
Giovanni Ossola
Giovanni Ossola
Automated computation of scattering amplitudes
13 pages, v2: references corrected. Presented at the "International Workshop on Advanced Computing and Analysis Techniques in Physics Research" (ACAT2013), Beijing, China, May 2013
null
10.1088/1742-6596/523/1/012040
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We review some of the recent advances in the computation of one-loop scattering amplitudes which led to the construction of efficient and automated computational tools for NLO predictions. Particular attention is devoted to unitarity-based methods and integrand-level reduction techniques. Extensions of one-loop integrand-level techniques to higher orders are also briefly illustrated.
[ { "created": "Fri, 11 Oct 2013 17:33:27 GMT", "version": "v1" }, { "created": "Fri, 8 Nov 2013 19:34:42 GMT", "version": "v2" } ]
2015-06-17
[ [ "Ossola", "Giovanni", "" ] ]
We review some of the recent advances in the computation of one-loop scattering amplitudes which led to the construction of efficient and automated computational tools for NLO predictions. Particular attention is devoted to unitarity-based methods and integrand-level reduction techniques. Extensions of one-loop integrand-level techniques to higher orders are also briefly illustrated.
1807.03312
Sung Hak Lim
Sung Hak Lim and Mihoko M. Nojiri
Spectral Analysis of Jet Substructure with Neural Networks: Boosted Higgs Case
18 pages, 12 figures, published in JHEP. A cut-based analysis is added
JHEP10(2018)181
10.1007/JHEP10(2018)181
KEK-TH-2060
hep-ph hep-ex stat.ML
http://creativecommons.org/licenses/by/4.0/
Jets from boosted heavy particles have a typical angular scale which can be used to distinguish them from QCD jets. We introduce a machine learning strategy for jet substructure analysis using a spectral function on the angular scale. The angular spectrum allows us to scan energy deposits over the angle between a pair of particles in a highly visual way. We set up an artificial neural network (ANN) to find out characteristic shapes of the spectra of the jets from heavy particle decays. By taking the Higgs jets and QCD jets as examples, we show that the ANN of the angular spectrum input has similar performance to existing taggers. In addition, some improvement is seen when additional extra radiations occur. Notably, the new algorithm automatically combines the information of the multi-point correlations in the jet.
[ { "created": "Mon, 9 Jul 2018 18:00:04 GMT", "version": "v1" }, { "created": "Tue, 30 Oct 2018 17:22:29 GMT", "version": "v2" } ]
2018-10-31
[ [ "Lim", "Sung Hak", "" ], [ "Nojiri", "Mihoko M.", "" ] ]
Jets from boosted heavy particles have a typical angular scale which can be used to distinguish them from QCD jets. We introduce a machine learning strategy for jet substructure analysis using a spectral function on the angular scale. The angular spectrum allows us to scan energy deposits over the angle between a pair of particles in a highly visual way. We set up an artificial neural network (ANN) to find out characteristic shapes of the spectra of the jets from heavy particle decays. By taking the Higgs jets and QCD jets as examples, we show that the ANN of the angular spectrum input has similar performance to existing taggers. In addition, some improvement is seen when additional extra radiations occur. Notably, the new algorithm automatically combines the information of the multi-point correlations in the jet.
1701.01551
Wei Chen
Hua-Xing Chen, Wei Chen, Jun He, Xiang Liu, and Shi-Lin Zhu
The hidden-charm multiquark states
Plenary talk at the 26th International Nuclear Physics Conference, 11-16 September 2016, Adelaide, Australia
POS (INPC2016) 374
null
null
hep-ph hep-ex hep-lat nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Since 2003 many charmonium-like states were observed experimentally. Especially those charged charmonium-like $Z_c$ states and bottomonium-like $Z_b$ states cannot be accommodated within the naive quark model, which are good candidates of either the hidden-charm tetraquark states or molecules composed of a pair of charmed mesons. In 2015, the LHCb Collaboration discovered two hidden-charm pentaquark states, which are also beyond the quark model. In this talk, we review the current experimental progress and investigate various theoretical interpretations of these candidates of the multiquark states. We list the puzzles and theoretical challenges of these models when confronted with the experimental data. We also discuss possible future measurements which may distinguish the theoretical schemes on the underlying structures of the hidden-charm multiquark states.
[ { "created": "Fri, 6 Jan 2017 06:07:55 GMT", "version": "v1" } ]
2017-01-10
[ [ "Chen", "Hua-Xing", "" ], [ "Chen", "Wei", "" ], [ "He", "Jun", "" ], [ "Liu", "Xiang", "" ], [ "Zhu", "Shi-Lin", "" ] ]
Since 2003 many charmonium-like states were observed experimentally. Especially those charged charmonium-like $Z_c$ states and bottomonium-like $Z_b$ states cannot be accommodated within the naive quark model, which are good candidates of either the hidden-charm tetraquark states or molecules composed of a pair of charmed mesons. In 2015, the LHCb Collaboration discovered two hidden-charm pentaquark states, which are also beyond the quark model. In this talk, we review the current experimental progress and investigate various theoretical interpretations of these candidates of the multiquark states. We list the puzzles and theoretical challenges of these models when confronted with the experimental data. We also discuss possible future measurements which may distinguish the theoretical schemes on the underlying structures of the hidden-charm multiquark states.
hep-ph/0201032
Yara do Amaral Coutinho
F.M.L. Almeida Jr., Y. A. Coutinho, J. A. Martins Sim\~oes and M.A.B. do Vale
Heavy Majorana neutrinos at a very large electron-proton collider
3 pages and 5 figures To appear in Physical Review D
null
null
null
hep-ph
null
We study the discovery potential for detecting new neutral heavy Majorana leptons as suggested by some extentions of the Standard Model in recently proposed electron-proton colliders. Since 1998-1999 the option of an electron-proton collider for the Very Large Hadron Collider at Fermilab operating with the proton booster has been considered. We study the reaction $e^{-}p \longrightarrow e^{+}+ jets$ and present estimates for the signal and Standard Model background including hadronization.
[ { "created": "Mon, 7 Jan 2002 12:29:14 GMT", "version": "v1" }, { "created": "Tue, 21 May 2002 13:34:05 GMT", "version": "v2" } ]
2007-05-23
[ [ "Almeida", "F. M. L.", "Jr." ], [ "Coutinho", "Y. A.", "" ], [ "Simões", "J. A. Martins", "" ], [ "Vale", "M. A. B. do", "" ] ]
We study the discovery potential for detecting new neutral heavy Majorana leptons as suggested by some extentions of the Standard Model in recently proposed electron-proton colliders. Since 1998-1999 the option of an electron-proton collider for the Very Large Hadron Collider at Fermilab operating with the proton booster has been considered. We study the reaction $e^{-}p \longrightarrow e^{+}+ jets$ and present estimates for the signal and Standard Model background including hadronization.
1401.4458
Ian Moult
Andrew J. Larkoski, Ian Moult, Duff Neill
Toward Multi-Differential Cross Sections: Measuring Two Angularities on a Single Jet
43 pages plus appendices, 8 figures. v2 as published in JHEP. minor typos corrected
null
10.1007/JHEP09(2014)046
MIT-CTP 4525
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The analytic study of differential cross sections in QCD has typically focused on individual observables, such as mass or thrust, to great success. Here, we present a first study of double differential jet cross sections considering two recoil-free angularities measured on a single jet. By analyzing the phase space defined by the two angularities and using methods from soft-collinear effective theory, we prove that the double differential cross section factorizes at the boundaries of the phase space. We also show that the cross section in the bulk of the phase space cannot be factorized using only soft and collinear modes, excluding the possibility of a global factorization theorem in soft-collinear effective theory. Nevertheless, we are able to define a simple interpolation procedure that smoothly connects the factorization theorem at one boundary to the other. We present an explicit example of this at next-to-leading logarithmic accuracy and show that the interpolation is unique up to $\alpha_s^4$ order in the exponent of the cross section, under reasonable assumptions. This is evidence that the interpolation is sufficiently robust to account for all logarithms in the bulk of phase space to the accuracy of the boundary factorization theorem. We compare our analytic calculation of the double differential cross section to Monte Carlo simulation and find qualitative agreement. Because our arguments rely on general structures of the phase space, we expect that much of our analysis would be relevant for the study of phenomenologically well-motivated observables, such as $N$-subjettiness, energy correlation functions, and planar flow.
[ { "created": "Fri, 17 Jan 2014 21:00:04 GMT", "version": "v1" }, { "created": "Fri, 5 Sep 2014 20:39:24 GMT", "version": "v2" } ]
2015-06-18
[ [ "Larkoski", "Andrew J.", "" ], [ "Moult", "Ian", "" ], [ "Neill", "Duff", "" ] ]
The analytic study of differential cross sections in QCD has typically focused on individual observables, such as mass or thrust, to great success. Here, we present a first study of double differential jet cross sections considering two recoil-free angularities measured on a single jet. By analyzing the phase space defined by the two angularities and using methods from soft-collinear effective theory, we prove that the double differential cross section factorizes at the boundaries of the phase space. We also show that the cross section in the bulk of the phase space cannot be factorized using only soft and collinear modes, excluding the possibility of a global factorization theorem in soft-collinear effective theory. Nevertheless, we are able to define a simple interpolation procedure that smoothly connects the factorization theorem at one boundary to the other. We present an explicit example of this at next-to-leading logarithmic accuracy and show that the interpolation is unique up to $\alpha_s^4$ order in the exponent of the cross section, under reasonable assumptions. This is evidence that the interpolation is sufficiently robust to account for all logarithms in the bulk of phase space to the accuracy of the boundary factorization theorem. We compare our analytic calculation of the double differential cross section to Monte Carlo simulation and find qualitative agreement. Because our arguments rely on general structures of the phase space, we expect that much of our analysis would be relevant for the study of phenomenologically well-motivated observables, such as $N$-subjettiness, energy correlation functions, and planar flow.
2407.09754
Ana Julia Mizher
A. Ayala and A. Mizher
Influence of magnetic field-induced anisotropic gluon pressure during pre-equilibrium in heavy-ion collisions: A faster road towards isotropization
5 pages, 5 figures
null
null
null
hep-ph hep-th nucl-th
http://creativecommons.org/licenses/by/4.0/
Magnetic fields of a large intensity can be generated in peripheral high-energy heavy-ion collisions. Although their intensity drops fast and, moreover, it is not clear whether these fields last long enough to induce a magnetization during the quark-gluon plasma phase, most of the models and simulations predict a significant intensity that lasts up to proper times of order 1 fm after the beginning of the reaction, which is a typical time for the hydrodynamical phase to start. This interval of time is referred to as the pre-equilibrium stage. The evolution of the reaction during pre-equilibrium is thus likely to be influenced by these fields. In this work we adopt a strong field approximation to study the effects of the magnetic field-induced anisotropy on the gluon pressure. We include this anisotropy within the description obtained by means of Effective Kinetic Theory and explore the consequences to reach isotropization at proper times of order 1 fm. We show that when including the magnetic field effects, isotropization is achieved faster.
[ { "created": "Sat, 13 Jul 2024 03:09:45 GMT", "version": "v1" } ]
2024-07-16
[ [ "Ayala", "A.", "" ], [ "Mizher", "A.", "" ] ]
Magnetic fields of a large intensity can be generated in peripheral high-energy heavy-ion collisions. Although their intensity drops fast and, moreover, it is not clear whether these fields last long enough to induce a magnetization during the quark-gluon plasma phase, most of the models and simulations predict a significant intensity that lasts up to proper times of order 1 fm after the beginning of the reaction, which is a typical time for the hydrodynamical phase to start. This interval of time is referred to as the pre-equilibrium stage. The evolution of the reaction during pre-equilibrium is thus likely to be influenced by these fields. In this work we adopt a strong field approximation to study the effects of the magnetic field-induced anisotropy on the gluon pressure. We include this anisotropy within the description obtained by means of Effective Kinetic Theory and explore the consequences to reach isotropization at proper times of order 1 fm. We show that when including the magnetic field effects, isotropization is achieved faster.
2112.13436
Alessandro Pilloni
JPAC Collaboration: Miguel Albaladejo, Lukasz Bibrzycki, Sebastian M. Dawid, Cesar Fernandez-Ramirez, Sergi Gonzalez-Solis, Astrid N. Hiller Blin, Andrew W. Jackura, Vincent Mathieu, Mikhail Mikhasenko, Victor I. Mokeev, Emilie Passemar, Alessandro Pilloni, Arkaitz Rodas, Jorge A. Silva-Castro, Wyatt A. Smith, Adam P. Szczepaniak, Daniel Winney
Novel approaches in Hadron Spectroscopy
98 pages, 58 figures. To appear in Progress in Particle and Nuclear Physics
Prog. Part. Nucl. Phys. 127 (2022) 103981
10.1016/j.ppnp.2022.103981
LA-UR-21-31664, JLAB-THY-22-3459
hep-ph hep-ex nucl-th
http://creativecommons.org/licenses/by-nc-nd/4.0/
The last two decades have witnessed the discovery of a myriad of new and unexpected hadrons. The future holds more surprises for us, thanks to new-generation experiments. Understanding the signals and determining the properties of the states requires a parallel theoretical effort. To make full use of available and forthcoming data, a careful amplitude modeling is required, together with a sound treatment of the statistical uncertainties, and a systematic survey of the model dependencies. We review the contributions made by the Joint Physics Analysis Center to the field of hadron spectroscopy.
[ { "created": "Sun, 26 Dec 2021 18:53:14 GMT", "version": "v1" }, { "created": "Fri, 1 Jul 2022 13:00:38 GMT", "version": "v2" } ]
2022-10-24
[ [ "JPAC Collaboration", "", "" ], [ "Albaladejo", "Miguel", "" ], [ "Bibrzycki", "Lukasz", "" ], [ "Dawid", "Sebastian M.", "" ], [ "Fernandez-Ramirez", "Cesar", "" ], [ "Gonzalez-Solis", "Sergi", "" ], [ "Blin", ...
The last two decades have witnessed the discovery of a myriad of new and unexpected hadrons. The future holds more surprises for us, thanks to new-generation experiments. Understanding the signals and determining the properties of the states requires a parallel theoretical effort. To make full use of available and forthcoming data, a careful amplitude modeling is required, together with a sound treatment of the statistical uncertainties, and a systematic survey of the model dependencies. We review the contributions made by the Joint Physics Analysis Center to the field of hadron spectroscopy.
1209.2716
Roman Kogler
M. Baak, M. Goebel, J. Haller, A. Hoecker, D. Kennedy, R. Kogler, K. Moenig, M. Schott, J. Stelzer
The Electroweak Fit of the Standard Model after the Discovery of a New Boson at the LHC
11 pages, 5 figures, version submitted to EPJ-C
Eur. Phys. J. C72 (2012) 2205
10.1140/epjc/s10052-012-2205-9
DESY-12-154
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In view of the discovery of a new boson by the ATLAS and CMS Collaborations at the LHC, we present an update of the global Standard Model (SM) fit to electroweak precision data. Assuming the new particle to be the SM Higgs boson, all fundamental parameters of the SM are known allowing, for the first time, to overconstrain the SM at the electroweak scale and assert its validity. Including the effects of radiative corrections and the experimental and theoretical uncertainties, the global fit exhibits a p-value of 0.07. The mass measurements by ATLAS and CMS agree within 1.3sigma with the indirect determination M_H=(94 +25 -22) GeV. Within the SM the W boson mass and the effective weak mixing angle can be accurately predicted to be M_W=(80.359 +- 0.011) GeV and sin^2(theta_eff^ell)=(0.23150 +- 0.00010) from the global fit. These results are compatible with, and exceed in precision, the direct measurements. For the indirect determination of the top quark mass we find m_t=(175.8 +2.7 -2.4) GeV, in agreement with the kinematic and cross-section based measurements.
[ { "created": "Wed, 12 Sep 2012 20:15:26 GMT", "version": "v1" }, { "created": "Tue, 25 Sep 2012 11:58:48 GMT", "version": "v2" } ]
2013-06-05
[ [ "Baak", "M.", "" ], [ "Goebel", "M.", "" ], [ "Haller", "J.", "" ], [ "Hoecker", "A.", "" ], [ "Kennedy", "D.", "" ], [ "Kogler", "R.", "" ], [ "Moenig", "K.", "" ], [ "Schott", "M.", "" ]...
In view of the discovery of a new boson by the ATLAS and CMS Collaborations at the LHC, we present an update of the global Standard Model (SM) fit to electroweak precision data. Assuming the new particle to be the SM Higgs boson, all fundamental parameters of the SM are known allowing, for the first time, to overconstrain the SM at the electroweak scale and assert its validity. Including the effects of radiative corrections and the experimental and theoretical uncertainties, the global fit exhibits a p-value of 0.07. The mass measurements by ATLAS and CMS agree within 1.3sigma with the indirect determination M_H=(94 +25 -22) GeV. Within the SM the W boson mass and the effective weak mixing angle can be accurately predicted to be M_W=(80.359 +- 0.011) GeV and sin^2(theta_eff^ell)=(0.23150 +- 0.00010) from the global fit. These results are compatible with, and exceed in precision, the direct measurements. For the indirect determination of the top quark mass we find m_t=(175.8 +2.7 -2.4) GeV, in agreement with the kinematic and cross-section based measurements.
hep-ph/9904474
Bernabeu
J. Bernabeu
CP, T Violation in Neutrino Oscillations
Proc. Weak Interactions and Neutrinos WIN'99
null
null
FTUV/99-28
hep-ph
null
The manifestation of CP, T violation in the leptonic sector is studied for flavour neutrino oscillations, both in vacuum and in matter. Different conditions of short-base-line versus long-base-line experiments are discussed.
[ { "created": "Wed, 28 Apr 1999 10:50:29 GMT", "version": "v1" } ]
2007-05-23
[ [ "Bernabeu", "J.", "" ] ]
The manifestation of CP, T violation in the leptonic sector is studied for flavour neutrino oscillations, both in vacuum and in matter. Different conditions of short-base-line versus long-base-line experiments are discussed.
1811.01982
Vicent Mateu
Vicent Mateu, Pablo G. Ortega, David R. Entem and Francisco Fernandez
Calibrating the Na\"ive Cornell Model with NRQCD
22 pages, 13 figures, 3 tables
Eur. Phys. J. C (2019) 79:323
10.1140/epjc/s10052-019-6808-2
IFT-UAM/CSIC-18-109
hep-ph hep-lat
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Along the years, the Cornell Model has been extraordinarily successful in describing hadronic phenomenology, in particular in physical situations for which an effective theory of the strong interactions such as NRQCD cannot be applied. As a consequence of its achievements, a relevant question is whether its model parameters can somehow be related to fundamental constants of QCD. We shall give a first answer in this article by comparing the predictions of both approaches. Building on results from a previous study on heavy meson spectroscopy, we calibrate the Cornell model employing NRQCD predictions for the lowest-lying bottomonium states up to N$^3$LO, in which the bottom mass is varied within a wide range. We find that the Cornell model mass parameter can be identified, within perturbative uncertainties, with the MSR mass at the scale $R = 1\,$GeV. This identification holds for any value of $\alpha_s$ or the bottom mass, and for all perturbative orders investigated. Furthermore, we show that: a) the "string tension" parameter is independent of the bottom mass, and b) the Coulomb strength $\kappa$ of the Cornell model can be related to the QCD strong coupling constant $\alpha_s$ at a characteristic non-relativistic scale. We also show how to remove the $u=1/2$ renormalon of the static QCD potential and sum-up large logs related to the renormalon subtraction by switching to the low-scale, short-distance MSR mass, and using R-evolution. Our R-improved expression for the static potential remains independent of the heavy quark mass value and agrees with lattice QCD results for values of the radius as large as $0.8\,$fm, and with the Cornell model potential at long distances. Finally we show that for moderate values of $r$, the R-improved NRQCD and Cornell static potentials are in head-on agreement.
[ { "created": "Mon, 5 Nov 2018 19:03:16 GMT", "version": "v1" }, { "created": "Thu, 25 Apr 2019 10:03:29 GMT", "version": "v2" } ]
2019-04-26
[ [ "Mateu", "Vicent", "" ], [ "Ortega", "Pablo G.", "" ], [ "Entem", "David R.", "" ], [ "Fernandez", "Francisco", "" ] ]
Along the years, the Cornell Model has been extraordinarily successful in describing hadronic phenomenology, in particular in physical situations for which an effective theory of the strong interactions such as NRQCD cannot be applied. As a consequence of its achievements, a relevant question is whether its model parameters can somehow be related to fundamental constants of QCD. We shall give a first answer in this article by comparing the predictions of both approaches. Building on results from a previous study on heavy meson spectroscopy, we calibrate the Cornell model employing NRQCD predictions for the lowest-lying bottomonium states up to N$^3$LO, in which the bottom mass is varied within a wide range. We find that the Cornell model mass parameter can be identified, within perturbative uncertainties, with the MSR mass at the scale $R = 1\,$GeV. This identification holds for any value of $\alpha_s$ or the bottom mass, and for all perturbative orders investigated. Furthermore, we show that: a) the "string tension" parameter is independent of the bottom mass, and b) the Coulomb strength $\kappa$ of the Cornell model can be related to the QCD strong coupling constant $\alpha_s$ at a characteristic non-relativistic scale. We also show how to remove the $u=1/2$ renormalon of the static QCD potential and sum-up large logs related to the renormalon subtraction by switching to the low-scale, short-distance MSR mass, and using R-evolution. Our R-improved expression for the static potential remains independent of the heavy quark mass value and agrees with lattice QCD results for values of the radius as large as $0.8\,$fm, and with the Cornell model potential at long distances. Finally we show that for moderate values of $r$, the R-improved NRQCD and Cornell static potentials are in head-on agreement.
hep-ph/0608103
Ted Barnes
T.Barnes (1 and 2) ((1) Physics Division, Oak Ridge National Laboratory, (2) Dept. of Physics and Astronomy, Univ. of Tennessee)
The XYZs of Charmonium at BES
5 pages, 1 eps figure. Invited contribution to the International Workshop on Tau-Charm Physics Charm2006 (5-7 June 2006, Beijing, China)
Int.J.Mod.Phys. A21 (2006) 5583-5591
10.1142/S0217751X0603477X
null
hep-ph nucl-th
null
This contribution reviews some recent developments in charmonium spectroscopy, and discusses related theoretical predictions. The spectrum of states, strong decays of states above open charm threshold, electromagnetic transitions, and issues related to the recent discoveries of the "XYZ" states are discussed. Contributions that BES can make to our understanding of charmonium and related states are stressed in particular.
[ { "created": "Wed, 9 Aug 2006 20:09:32 GMT", "version": "v1" } ]
2009-11-11
[ [ "Barnes", "T.", "", "1 and 2" ] ]
This contribution reviews some recent developments in charmonium spectroscopy, and discusses related theoretical predictions. The spectrum of states, strong decays of states above open charm threshold, electromagnetic transitions, and issues related to the recent discoveries of the "XYZ" states are discussed. Contributions that BES can make to our understanding of charmonium and related states are stressed in particular.
1811.06461
Yannick Ulrich
T. Engel, C. Gnendiger, A. Signer, Y. Ulrich
Small-mass effects in heavy-to-light form factors
20 pages, 4 figures, 1 ancillary file, published version
J. High Energ. Phys. (2019) 2019: 118
10.1007/JHEP02(2019)118
PSI-PR-18-13, ZU-TH 40/18
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present the heavy-to-light form factors with two different non-vanishing masses at next-to-next-to-leading order and study its expansion in the small mass. The leading term of this small-mass expansion leads to a factorized expression for the form factor. The presence of a second mass results in a new feature, in that the soft contribution develops a factorization anomaly. This cancels with the corresponding anomaly in the collinear contribution. With the generalized factorization presented here, it is possible to obtain the leading small-mass terms for processes with large masses, such as muon-electron scattering, from the corresponding massless amplitude and the soft contribution.
[ { "created": "Thu, 15 Nov 2018 16:52:18 GMT", "version": "v1" }, { "created": "Thu, 14 Mar 2019 10:45:28 GMT", "version": "v2" } ]
2019-03-15
[ [ "Engel", "T.", "" ], [ "Gnendiger", "C.", "" ], [ "Signer", "A.", "" ], [ "Ulrich", "Y.", "" ] ]
We present the heavy-to-light form factors with two different non-vanishing masses at next-to-next-to-leading order and study its expansion in the small mass. The leading term of this small-mass expansion leads to a factorized expression for the form factor. The presence of a second mass results in a new feature, in that the soft contribution develops a factorization anomaly. This cancels with the corresponding anomaly in the collinear contribution. With the generalized factorization presented here, it is possible to obtain the leading small-mass terms for processes with large masses, such as muon-electron scattering, from the corresponding massless amplitude and the soft contribution.
hep-ph/0104290
Alexander Bakulev
A. P. Bakulev, S. V. Mikhailov, N. G. Stefanis
On a QCD-based pion distribution amplitude vs. recent experimental data
4 pages in moriond style; 1 photo and 2 figures unite 7 EPS files; to appear in Proc. of XXXIVth Rencontres de Moriond "QCD and High Energy Hadronic Interactions", March 17 to 24, 2001, Les Arcs, Savoie, France
Conf.Proc.C010317:133-136,2002
null
RUB-TPII-04/01
hep-ph
null
Using QCD sum rules with nonlocal condensates the twist-2 pion distribution amplitude is determined by means of its moments and their confidence intervals, including also radiative corrections. An admissible set of pion distribution amplitudes is constructed in the a_2, a_4 plane of the Gegenbauer polynomial expansion coefficients. The determined a_2, a_4 region strongly overlaps with that extracted from the CLEO data by Schmedding and Yakovlev. Comparisons are given with results from Fermilab experiment E791 and recent lattice calculations.
[ { "created": "Fri, 27 Apr 2001 16:20:14 GMT", "version": "v1" } ]
2008-11-26
[ [ "Bakulev", "A. P.", "" ], [ "Mikhailov", "S. V.", "" ], [ "Stefanis", "N. G.", "" ] ]
Using QCD sum rules with nonlocal condensates the twist-2 pion distribution amplitude is determined by means of its moments and their confidence intervals, including also radiative corrections. An admissible set of pion distribution amplitudes is constructed in the a_2, a_4 plane of the Gegenbauer polynomial expansion coefficients. The determined a_2, a_4 region strongly overlaps with that extracted from the CLEO data by Schmedding and Yakovlev. Comparisons are given with results from Fermilab experiment E791 and recent lattice calculations.
1710.03377
Digesh Raut
Arindam Das, Nobuchika Okada, and Digesh Raut
Enhanced pair production of heavy Majorana neutrinos at LHC
10 pages, 2 figures, revised version (discussion extended, Figure 1 revised, typos corrected, new references added)
Phys. Rev. D 97, 115023 (2018)
10.1103/PhysRevD.97.115023
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Towards experimental confirmations of the type-I seesaw mechanism, we explore a prospect of discovering the heavy Majorana right-handed neutrinos (RHNs) from a resonant production of a new massive gauge boson ($Z^{\prime}$) and its subsequent decay into a pair of RHNs ($Z^{\prime}\to NN$) at the future LHC. Recent simulation studies have shown that the discovery of the RHNs through this process is promising in the future. However, the current LHC data very severely constrains the production cross section of the $Z^{\prime}$ boson into a dilepton final states, $pp \to Z^{\prime}\to \ell^{+}\ell^{-} $ ($\ell=e$ or $\mu$). Extrapolating the current bound to the future, we find that a significant enhancement of the branching ratio ${\rm BR}(Z^{\prime}\to NN$) over ${\rm BR}(Z^{\prime}\to \ell^{+}\ell^{-}$) is necessary for the future discovery of RHNs. As a well-motivated simple extension of the Standard Model (SM) to incorporate the $Z^\prime$ boson and the type-I seesaw mechanism, we consider the minimal U(1)$_X$ model. We point out that this model can yield a significant enhancement up to ${\rm BR}(Z^{\prime}\to NN)/{\rm BR}(Z^{\prime}\to \ell^{+}\ell^{-}) \simeq 5$ (per generation). This is in sharp contrast with the minimal $B-L$ model, a benchmark scenario commonly used in simulation studies, which predicts ${\rm BR}(Z^{\prime}\to NN)/{\rm BR}(Z^{\prime}\to \ell^{+}\ell^{-}) \simeq 0.5$ (per generation). With such an enhancement and a realistic model-parameter choice to reproduce the neutrino oscillation data, we conclude that the possibility of discovering RHNs with a $300 \; {\rm fb}^{-1}$ luminosity implies that the $Z^\prime$ boson will be discovered with a luminosity of $170.5 \;{\rm fb}^{-1}$ ($125 \; {\rm fb}^{-1}$) for the normal (inverted) hierarchy of the light neutrino mass pattern.
[ { "created": "Tue, 10 Oct 2017 02:12:24 GMT", "version": "v1" }, { "created": "Tue, 1 May 2018 02:44:34 GMT", "version": "v2" } ]
2018-06-20
[ [ "Das", "Arindam", "" ], [ "Okada", "Nobuchika", "" ], [ "Raut", "Digesh", "" ] ]
Towards experimental confirmations of the type-I seesaw mechanism, we explore a prospect of discovering the heavy Majorana right-handed neutrinos (RHNs) from a resonant production of a new massive gauge boson ($Z^{\prime}$) and its subsequent decay into a pair of RHNs ($Z^{\prime}\to NN$) at the future LHC. Recent simulation studies have shown that the discovery of the RHNs through this process is promising in the future. However, the current LHC data very severely constrains the production cross section of the $Z^{\prime}$ boson into a dilepton final states, $pp \to Z^{\prime}\to \ell^{+}\ell^{-} $ ($\ell=e$ or $\mu$). Extrapolating the current bound to the future, we find that a significant enhancement of the branching ratio ${\rm BR}(Z^{\prime}\to NN$) over ${\rm BR}(Z^{\prime}\to \ell^{+}\ell^{-}$) is necessary for the future discovery of RHNs. As a well-motivated simple extension of the Standard Model (SM) to incorporate the $Z^\prime$ boson and the type-I seesaw mechanism, we consider the minimal U(1)$_X$ model. We point out that this model can yield a significant enhancement up to ${\rm BR}(Z^{\prime}\to NN)/{\rm BR}(Z^{\prime}\to \ell^{+}\ell^{-}) \simeq 5$ (per generation). This is in sharp contrast with the minimal $B-L$ model, a benchmark scenario commonly used in simulation studies, which predicts ${\rm BR}(Z^{\prime}\to NN)/{\rm BR}(Z^{\prime}\to \ell^{+}\ell^{-}) \simeq 0.5$ (per generation). With such an enhancement and a realistic model-parameter choice to reproduce the neutrino oscillation data, we conclude that the possibility of discovering RHNs with a $300 \; {\rm fb}^{-1}$ luminosity implies that the $Z^\prime$ boson will be discovered with a luminosity of $170.5 \;{\rm fb}^{-1}$ ($125 \; {\rm fb}^{-1}$) for the normal (inverted) hierarchy of the light neutrino mass pattern.
2111.03645
Shinsuke Kawai
Shinsuke Kawai, Nobuchika Okada
Gravitino constraints on supergravity inflation
5 pages, 2 figures. v3: correction in Fig.2 caption
PRD 105 (2022) L101302
10.1103/PhysRevD.105.L101302
null
hep-ph astro-ph.CO hep-ex hep-th
http://creativecommons.org/licenses/by/4.0/
Supergravity embedding of the Standard Model of particle physics provides phenomenologically well-motivated and observationally viable inflationary scenarios. We investigate a class of inflationary models based on the superconformal framework of supergravity and discuss constraints from the reheating temperature, with the particular focus on the gravitino problem inherent in these scenarios. We point out that a large part of the parameter space within the latest BICEP/Keck 95\% confidence contour may have been excluded by the gravitino constraints, depending on the mass scale of the inflaton. Precision measurements of the scalar spectral index by a future mission may rule out some of these scenarios conclusively.
[ { "created": "Fri, 5 Nov 2021 17:54:31 GMT", "version": "v1" }, { "created": "Wed, 4 May 2022 14:44:08 GMT", "version": "v2" }, { "created": "Wed, 1 Mar 2023 09:21:52 GMT", "version": "v3" } ]
2023-03-02
[ [ "Kawai", "Shinsuke", "" ], [ "Okada", "Nobuchika", "" ] ]
Supergravity embedding of the Standard Model of particle physics provides phenomenologically well-motivated and observationally viable inflationary scenarios. We investigate a class of inflationary models based on the superconformal framework of supergravity and discuss constraints from the reheating temperature, with the particular focus on the gravitino problem inherent in these scenarios. We point out that a large part of the parameter space within the latest BICEP/Keck 95\% confidence contour may have been excluded by the gravitino constraints, depending on the mass scale of the inflaton. Precision measurements of the scalar spectral index by a future mission may rule out some of these scenarios conclusively.
1006.2372
Joachim Kopp
Boris Kayser, Joachim Kopp (Fermilab), R. G. Hamish Robertson (U of Washington), Petr Vogel (Caltech)
On a theory of neutrino oscillations with entanglement
RevTeX 4, 12 pages, 1 figure; v2: Minor clarifications, references added
Phys.Rev.D82:093003,2010
10.1103/PhysRevD.82.093003
FERMILAB-PUB-10-194-T
hep-ph hep-ex nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We show that, despite appearances, a theoretical approach to neutrino oscillation in which the neutrino and its interaction partners are entangled yields the standard result for the neutrino oscillation wavelength. We also shed some light on the question of why plane-wave approaches to the neutrino oscillation problem can yield the correct oscillation wavelength even though they do not explicitly account for the localization of the neutrino source and the detector.
[ { "created": "Fri, 11 Jun 2010 19:36:43 GMT", "version": "v1" }, { "created": "Wed, 3 Nov 2010 17:16:21 GMT", "version": "v2" } ]
2010-11-05
[ [ "Kayser", "Boris", "", "Fermilab" ], [ "Kopp", "Joachim", "", "Fermilab" ], [ "Robertson", "R. G. Hamish", "", "U of\n Washington" ], [ "Vogel", "Petr", "", "Caltech" ] ]
We show that, despite appearances, a theoretical approach to neutrino oscillation in which the neutrino and its interaction partners are entangled yields the standard result for the neutrino oscillation wavelength. We also shed some light on the question of why plane-wave approaches to the neutrino oscillation problem can yield the correct oscillation wavelength even though they do not explicitly account for the localization of the neutrino source and the detector.
hep-ph/9601226
Xuan-Yem Pham
X. Y. Pham and M. Gourdin
A new CP violation mechanism generated by the standard neutral Higgs boson : the $\eta \to \pi + \pi $ case
9 pages (Latex), 3 figures
Phys.Lett. B385 (1996) 231-236; Erratum-ibid. B390 (1997) 451
10.1016/0370-2693(96)00891-X
LPTHE/PAR/96-01
hep-ph
null
Strictly within the standard electro-weak interaction, CP violation in the flavour conserving process $\eta \rightarrow \pi + \pi $ could originate from the mixing of the $\eta$ meson with the virtual scalar Higgs boson $ H^{0}$ via $W$ and top quark exchange. The parity-violation carried by weak gauge bosons makes the mixing possible by quantum effect at two-loop level. Nowhere the Kobayashi-Maskawa (KM) phase mechanism is needed. The phenomenon reveals an unexpected new role of the Higgs boson in the CP symmetry breaking. For the Higgs mass between 100-600 GeV, the $\eta \rightarrow \pi +\pi $ branching ratio is found to be $3.6 \cdot 10^{-26} - 2.4 \cdot 10^{-29}$ , hence CP violation mechanisms beyond the Standard Model are the only ones that could give rise to its observation at existing or near future $\eta$ factories, unless the Higgs mass is improbably as light as 550 $MeV$.
[ { "created": "Mon, 8 Jan 1996 16:30:16 GMT", "version": "v1" }, { "created": "Wed, 10 Jan 1996 17:24:51 GMT", "version": "v2" }, { "created": "Tue, 11 Jun 1996 16:59:07 GMT", "version": "v3" } ]
2009-10-28
[ [ "Pham", "X. Y.", "" ], [ "Gourdin", "M.", "" ] ]
Strictly within the standard electro-weak interaction, CP violation in the flavour conserving process $\eta \rightarrow \pi + \pi $ could originate from the mixing of the $\eta$ meson with the virtual scalar Higgs boson $ H^{0}$ via $W$ and top quark exchange. The parity-violation carried by weak gauge bosons makes the mixing possible by quantum effect at two-loop level. Nowhere the Kobayashi-Maskawa (KM) phase mechanism is needed. The phenomenon reveals an unexpected new role of the Higgs boson in the CP symmetry breaking. For the Higgs mass between 100-600 GeV, the $\eta \rightarrow \pi +\pi $ branching ratio is found to be $3.6 \cdot 10^{-26} - 2.4 \cdot 10^{-29}$ , hence CP violation mechanisms beyond the Standard Model are the only ones that could give rise to its observation at existing or near future $\eta$ factories, unless the Higgs mass is improbably as light as 550 $MeV$.
hep-ph/0510063
Pierpaolo Mastrolia
Pierpaolo Mastrolia (UCLA)
CSW Diagrams and Electroweak Vector Bosons
8 pages, 2 figures, Talk given at the workshop QCD at Work 2005, Conversano (BA), Italy, June 16-20, 2005
null
10.1063/1.2163750
UCLA/05/TEP/28
hep-ph
null
Based on the joined work performed together with Z. Bern, D. Forde, and D. Kosower [1], in this talk it is recalled the (twistor-motivated) diagrammatic formalism describing tree-level scattering amplitudes presented by Cachazo, Svr\v{c}ek and Witten, and it is discussed an extension of the vertices and accompaining rules to the construction of vector-boson currents coupling to an arbitrary source.
[ { "created": "Wed, 5 Oct 2005 19:01:50 GMT", "version": "v1" } ]
2015-06-25
[ [ "Mastrolia", "Pierpaolo", "", "UCLA" ] ]
Based on the joined work performed together with Z. Bern, D. Forde, and D. Kosower [1], in this talk it is recalled the (twistor-motivated) diagrammatic formalism describing tree-level scattering amplitudes presented by Cachazo, Svr\v{c}ek and Witten, and it is discussed an extension of the vertices and accompaining rules to the construction of vector-boson currents coupling to an arbitrary source.
hep-ph/9809257
Antti Keranen
A. Keranen, J. Cleymans and E. Suhonen
On the exact conservation laws in thermal models and the analysis of AGS and SIS experimental results
Talk given at Strangeness in Quark Matter '98, Padova, Italy (1998). Submitted to J.Phys. G. 5 pages, 2 figures
J.Phys.G25:275-280,1999
10.1088/0954-3899/25/2/015
null
hep-ph
null
The production of hadrons in relativistic heavy ion collisions is studied using a statistical ensemble with thermal and chemical equilibrium. Special attention is given to exact conservation laws, i.e. certain charges are treated canonically instead of using the usual grand canonical approach. For small systems, the exact conservation of baryon number, strangeness and electric charge is to be taken into account. We have derived compact, analytical expressions for particle abundances in such ensemble. As an application, the change in $K/\pi$ ratios in AGS experiments with different interaction system sizes is well reproduced. The canonical treatment of three charges becomes impractical very quickly with increasing system size. Thus, we draw our attention to exact conservation of strangeness, and treat baryon number and electric charge grand canonically. We present expressions for particle abundances in such ensemble as well, and apply them to reproduce the large variety of particle ratios in GSI SIS 2 A GeV Ni-Ni experiments. At the energies considered here, the exact strangeness conservation fully accounts for strange particle suppression, and no extra chemical factor is needed.
[ { "created": "Fri, 4 Sep 1998 08:48:11 GMT", "version": "v1" } ]
2008-11-26
[ [ "Keranen", "A.", "" ], [ "Cleymans", "J.", "" ], [ "Suhonen", "E.", "" ] ]
The production of hadrons in relativistic heavy ion collisions is studied using a statistical ensemble with thermal and chemical equilibrium. Special attention is given to exact conservation laws, i.e. certain charges are treated canonically instead of using the usual grand canonical approach. For small systems, the exact conservation of baryon number, strangeness and electric charge is to be taken into account. We have derived compact, analytical expressions for particle abundances in such ensemble. As an application, the change in $K/\pi$ ratios in AGS experiments with different interaction system sizes is well reproduced. The canonical treatment of three charges becomes impractical very quickly with increasing system size. Thus, we draw our attention to exact conservation of strangeness, and treat baryon number and electric charge grand canonically. We present expressions for particle abundances in such ensemble as well, and apply them to reproduce the large variety of particle ratios in GSI SIS 2 A GeV Ni-Ni experiments. At the energies considered here, the exact strangeness conservation fully accounts for strange particle suppression, and no extra chemical factor is needed.
1009.3365
Helen Matskevich
S.M. Gerasyuta and E.E. Matskevich
Nonstrange baryonia
28 pages, latex
Int.J.Mod.Phys.E20:1419-1436,2011
10.1142/S0218301311018502
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The relativistic six-quark equations including the $u$, $d$ quarks and antiquarks are found. The nonstrange baryonia $B \bar B$ are constructed without the mixing of the quarks and antiquarks. The relativistic six-quark amplitudes of the baryonia are calculated. The poles of these amplitudes determine the masses of baryonia. 15 masses of baryonia are predicted. The mass of baryonium with the spin-parity $J^P=0^-$ $M=1835\, MeV$ is used as a fit.
[ { "created": "Fri, 17 Sep 2010 08:26:21 GMT", "version": "v1" } ]
2011-07-15
[ [ "Gerasyuta", "S. M.", "" ], [ "Matskevich", "E. E.", "" ] ]
The relativistic six-quark equations including the $u$, $d$ quarks and antiquarks are found. The nonstrange baryonia $B \bar B$ are constructed without the mixing of the quarks and antiquarks. The relativistic six-quark amplitudes of the baryonia are calculated. The poles of these amplitudes determine the masses of baryonia. 15 masses of baryonia are predicted. The mass of baryonium with the spin-parity $J^P=0^-$ $M=1835\, MeV$ is used as a fit.
hep-ph/0312204
Lokhtin
I.P. Lokhtin and A.M. Snigirev
Fast simulation of flow effects in central and semi-central heavy ion collisions at LHC
6 pages, LaTeX
null
null
SINP MSU 2004-14/753
hep-ph
null
The simple method for simulation of ``thermal'' hadron spectra in ultrarelativistic heavy ion collisions including longitudinal, transverse and elliptic flow is developed. The model is realized as fast Monte-Carlo event generator.
[ { "created": "Tue, 16 Dec 2003 10:12:37 GMT", "version": "v1" }, { "created": "Mon, 21 Jun 2004 14:02:32 GMT", "version": "v2" } ]
2007-05-23
[ [ "Lokhtin", "I. P.", "" ], [ "Snigirev", "A. M.", "" ] ]
The simple method for simulation of ``thermal'' hadron spectra in ultrarelativistic heavy ion collisions including longitudinal, transverse and elliptic flow is developed. The model is realized as fast Monte-Carlo event generator.