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1108.2772
Klaus Schubert
Klaus R. Schubert and J\"urgen Stiewe
Demonstration of K-Kbar, B-Bbar, and D-Dbar Transitions with a Pair of Coupled Pendula
15 pages, 6 figures
null
10.1088/0954-3899/39/3/033101
null
hep-ph physics.class-ph physics.pop-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A setup of two coupled and damped pendula is used to demonstrate the main features of transitions beween neutral K, D, B mesons and their respective antiparticles, including CP violation in K Kbar transitions. The transitions are described by two-state Schr\"odinger equations. Since the real parts of their solutions obey the same differential equations as the pendula coordinates, the pendulum motions can be used to represent the meson transitions. Video clips of the motions are attached as supplementary material.
[ { "created": "Sat, 13 Aug 2011 07:44:11 GMT", "version": "v1" }, { "created": "Wed, 7 Dec 2011 10:34:44 GMT", "version": "v2" } ]
2015-05-30
[ [ "Schubert", "Klaus R.", "" ], [ "Stiewe", "Jürgen", "" ] ]
A setup of two coupled and damped pendula is used to demonstrate the main features of transitions beween neutral K, D, B mesons and their respective antiparticles, including CP violation in K Kbar transitions. The transitions are described by two-state Schr\"odinger equations. Since the real parts of their solutions obey the same differential equations as the pendula coordinates, the pendulum motions can be used to represent the meson transitions. Video clips of the motions are attached as supplementary material.
hep-ph/0102259
Xiong Zhao-hua
Z. Xiong, J. M. Yang (Institute of Theoretical Physics, Academia Sinica)
Muon anomalous magnetic moment in technicolor models
refs and comments added
Phys.Lett. B508 (2001) 295-300
10.1016/S0370-2693(01)00521-4
null
hep-ph
null
Contributions to the muon anomalous magnetic moment are evaluated in the technicolor model with scalars and topcolor assisted technicolor model. In the technicolor model with scalars, the additional contributions come from the loops of scalars, which were found sizable only for a very large $f/f^{'}$ disfavored by the experiment of $b\to s\gamma$. The topcolor effect is also found to be large only for an unnaturally large $\tan\theta'$, and thus the previously evaluated loop effects of extended technicolor bosons, suppressed by $m_{\mu}^2/M_{ETC}^2$, must be resorted to account for the E821 experiment. So, if the E821 experiment result persists, it would be a challenge to technicolor models.
[ { "created": "Wed, 21 Feb 2001 03:34:16 GMT", "version": "v1" }, { "created": "Thu, 22 Feb 2001 08:44:59 GMT", "version": "v2" }, { "created": "Fri, 9 Mar 2001 09:53:10 GMT", "version": "v3" } ]
2009-11-07
[ [ "Xiong", "Z.", "", "Institute of Theoretical Physics, Academia\n Sinica" ], [ "Yang", "J. M.", "", "Institute of Theoretical Physics, Academia\n Sinica" ] ]
Contributions to the muon anomalous magnetic moment are evaluated in the technicolor model with scalars and topcolor assisted technicolor model. In the technicolor model with scalars, the additional contributions come from the loops of scalars, which were found sizable only for a very large $f/f^{'}$ disfavored by the experiment of $b\to s\gamma$. The topcolor effect is also found to be large only for an unnaturally large $\tan\theta'$, and thus the previously evaluated loop effects of extended technicolor bosons, suppressed by $m_{\mu}^2/M_{ETC}^2$, must be resorted to account for the E821 experiment. So, if the E821 experiment result persists, it would be a challenge to technicolor models.
1106.1599
Mosleh Almarashi
Mosleh M. Almarashi and Stefano Moretti
Reinforcing the no-lose theorem for NMSSM Higgs discovery at the LHC
19 pages, 9 figures, added comments and corrected typos
Phys.Rev.D84:035009,2011
10.1103/PhysRevD.84.035009
SHEP-11-13
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We show the potential of the LHC to detect a CP-even Higgs boson of the NMSSM, $h_1$ or $h_2$, decaying into two rather light CP-odd Higgs bosons, $a_1$, by exploiting the production mode based on Higgs-strahlung off $b$-quarks, i.e., the channel $pp\to b\bar b h_{1,2}$. We also consider the case of $h_2\to h_1 h_1$ decays. It is found that these decays have dominant BRs over large regions of the NMSSM parameter space where tan$\beta$ is large, a condition which also favours the $pp\to b\bar b h_{1,2}$ production rates. Further decays of the light Higgs boson pairs ($a_1$ and $h_1$) into photon, muon, tau and $b$ final states are also considered. The overall production and decay rates for these processes at inclusive level are sizable and should help extracting at least one Higgs boson signal over the NMSSM parameter space.
[ { "created": "Wed, 8 Jun 2011 17:01:38 GMT", "version": "v1" }, { "created": "Thu, 14 Jul 2011 15:54:00 GMT", "version": "v2" } ]
2011-09-08
[ [ "Almarashi", "Mosleh M.", "" ], [ "Moretti", "Stefano", "" ] ]
We show the potential of the LHC to detect a CP-even Higgs boson of the NMSSM, $h_1$ or $h_2$, decaying into two rather light CP-odd Higgs bosons, $a_1$, by exploiting the production mode based on Higgs-strahlung off $b$-quarks, i.e., the channel $pp\to b\bar b h_{1,2}$. We also consider the case of $h_2\to h_1 h_1$ decays. It is found that these decays have dominant BRs over large regions of the NMSSM parameter space where tan$\beta$ is large, a condition which also favours the $pp\to b\bar b h_{1,2}$ production rates. Further decays of the light Higgs boson pairs ($a_1$ and $h_1$) into photon, muon, tau and $b$ final states are also considered. The overall production and decay rates for these processes at inclusive level are sizable and should help extracting at least one Higgs boson signal over the NMSSM parameter space.
1305.2921
Angelo Monteux
Angelo Monteux (University of California, Santa Cruz)
Natural, R-parity violating supersymmetry and horizontal flavor symmetries
v3: version accepted for publication on PRD. Expanded discussion about the NMSSM and neutrinos, references added, minor clarifications, conclusions unchanged. 35 pages, revtex4.1
Phys. Rev. D 88, 045029 (2013)
10.1103/PhysRevD.88.045029
SCIPP 13/08
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The absence so far of any supersymmetric signals at the LHC pushes towards a rethinking of the assumptions underlying the MSSM. Because the large missing $E_T$ searches are inadequate to detect a LSP decaying within the detector, R-parity violating supersymmetry is still a good candidate for low energy, natural supersymmetry. We show that, in Froggatt-Nielsen-like models of horizontal symmetries, specific textures for the R-parity violating couplings are dictated by the symmetry, with the largest coupling involving the third generation fields. Lepton number can be an accidental symmetry of the renormalizable superpotential and barion number violation is given by a $\bar u\bar d\bar d$ operator. The collider phenomenology then mimics the main features of MFV R-parity violating supersymmetry. The LSP can evade current LHC supersymmetry searches, is allowed to be well below 1 TeV and at the same time all the constraints from proton decay and other low energy decays can be satisfied; in particular, dimension five operators allowed by R-parity but dangerous for the proton are under control, while neutrino masses are generated by the Weinberg operator. Assuming sub TeV ({\it natural}) superpartners, we obtain both upper and lower limits on the magnitude of the dominant R-parity violating coupling: a lower limit of order $10^{-9}$ arises from null LHC searches on R-hadrons and heavy stable charged particles, while a upper limit of order $10^{-3}$ follows from constraints on low-energy flavor changing neutral currents. Displaced vertices are predicted in the lower end of this range.
[ { "created": "Mon, 13 May 2013 20:00:04 GMT", "version": "v1" }, { "created": "Tue, 28 May 2013 16:15:04 GMT", "version": "v2" }, { "created": "Tue, 6 Aug 2013 20:56:44 GMT", "version": "v3" } ]
2013-08-30
[ [ "Monteux", "Angelo", "", "University of California, Santa Cruz" ] ]
The absence so far of any supersymmetric signals at the LHC pushes towards a rethinking of the assumptions underlying the MSSM. Because the large missing $E_T$ searches are inadequate to detect a LSP decaying within the detector, R-parity violating supersymmetry is still a good candidate for low energy, natural supersymmetry. We show that, in Froggatt-Nielsen-like models of horizontal symmetries, specific textures for the R-parity violating couplings are dictated by the symmetry, with the largest coupling involving the third generation fields. Lepton number can be an accidental symmetry of the renormalizable superpotential and barion number violation is given by a $\bar u\bar d\bar d$ operator. The collider phenomenology then mimics the main features of MFV R-parity violating supersymmetry. The LSP can evade current LHC supersymmetry searches, is allowed to be well below 1 TeV and at the same time all the constraints from proton decay and other low energy decays can be satisfied; in particular, dimension five operators allowed by R-parity but dangerous for the proton are under control, while neutrino masses are generated by the Weinberg operator. Assuming sub TeV ({\it natural}) superpartners, we obtain both upper and lower limits on the magnitude of the dominant R-parity violating coupling: a lower limit of order $10^{-9}$ arises from null LHC searches on R-hadrons and heavy stable charged particles, while a upper limit of order $10^{-3}$ follows from constraints on low-energy flavor changing neutral currents. Displaced vertices are predicted in the lower end of this range.
hep-ph/9911472
A. Shuvaev
M. G. Ryskin and A. G. Shuvaev
Classical pion fields in the presence of source
10 pages, LaTeX, 1 figure, epsfig.sty, corrected typos, added references
Phys.Atom.Nucl. 64 (2001) 1508-1512; Yad.Fiz. 64 (2001) 1584-1588
10.1134/1.1398944
null
hep-ph
null
Classical pion field similar to Disoriented Chiral Condensate (DCC) is considered in the presence of the external source. This field is similar to DCC in the sense that its isotopic orientation is specified with a single vector at the whole space. We study the classical field solutions in the nonlinear sigma-model both in the chiral limit with massless pion and for the finite pion mass. In both cases the field resembles the Coulomb field of charged particle however the nonlinear pion interactions lead to the existence of several solutions. In the massless case and for the very small size of the source there is the lot of classical solutions with finite discrete energies. In the more realistic situation of large nucleus (heavy ion) there are no stable solutions of the above type, but there is the possibility for the formation of the quasistationary states. They can live for a long time slowly decaying through the emission of very soft pions. The structure and the energies of these solutions is investigated numerically.
[ { "created": "Wed, 24 Nov 1999 17:03:06 GMT", "version": "v1" }, { "created": "Thu, 24 Feb 2000 10:33:48 GMT", "version": "v2" } ]
2009-10-31
[ [ "Ryskin", "M. G.", "" ], [ "Shuvaev", "A. G.", "" ] ]
Classical pion field similar to Disoriented Chiral Condensate (DCC) is considered in the presence of the external source. This field is similar to DCC in the sense that its isotopic orientation is specified with a single vector at the whole space. We study the classical field solutions in the nonlinear sigma-model both in the chiral limit with massless pion and for the finite pion mass. In both cases the field resembles the Coulomb field of charged particle however the nonlinear pion interactions lead to the existence of several solutions. In the massless case and for the very small size of the source there is the lot of classical solutions with finite discrete energies. In the more realistic situation of large nucleus (heavy ion) there are no stable solutions of the above type, but there is the possibility for the formation of the quasistationary states. They can live for a long time slowly decaying through the emission of very soft pions. The structure and the energies of these solutions is investigated numerically.
hep-ph/0408252
Xing Gang Wu
Tao Huang and Xing-Gang Wu
A Model for the Twist-3 Wave Function of the Pion and Its Contribution to the Pion Form Factor
22pages,4 figures. Phys.Rev. D70, 093013(2004) (in press)
Phys.Rev. D70 (2004) 093013
10.1103/PhysRevD.70.093013
null
hep-ph
null
A model for the twist-3 wave function $\psi_p(x,\mathbf{k_\perp})$ of the pion has been constructed based on the moment calculation by applying the QCD sum rules, whose distribution amplitude has a better end-point behavior than that of the asymptotic one. With this model wave function, the twist-3 contributions including both the usual helicity components ($\lambda_1+\lambda_2=0$) and the higher helicity components ($\lambda_1+\lambda_2=\pm 1$) to the pion form factor have been studied within the modified pQCD approach. Our results show that the twist-3 contribution drops fast and it becomes less than the twist-2 contribution at $Q^2\sim 10GeV^2$. The higher helicity components in the twist-3 wave function will give an extra suppression to the pion form factor. The model dependence of the twist-3 contribution to the pion form factor has been studied by comparing three different models. When all the power contributions, which include higher order in $\alpha_s$, higher helicities, higher twists in DA and etc., have been taken into account, it is expected that the hard contributions will fit the present experimental data well at the energy region where pQCD is applicable.
[ { "created": "Tue, 24 Aug 2004 03:34:54 GMT", "version": "v1" }, { "created": "Thu, 7 Oct 2004 04:35:48 GMT", "version": "v2" }, { "created": "Fri, 26 Nov 2004 00:07:44 GMT", "version": "v3" } ]
2009-11-10
[ [ "Huang", "Tao", "" ], [ "Wu", "Xing-Gang", "" ] ]
A model for the twist-3 wave function $\psi_p(x,\mathbf{k_\perp})$ of the pion has been constructed based on the moment calculation by applying the QCD sum rules, whose distribution amplitude has a better end-point behavior than that of the asymptotic one. With this model wave function, the twist-3 contributions including both the usual helicity components ($\lambda_1+\lambda_2=0$) and the higher helicity components ($\lambda_1+\lambda_2=\pm 1$) to the pion form factor have been studied within the modified pQCD approach. Our results show that the twist-3 contribution drops fast and it becomes less than the twist-2 contribution at $Q^2\sim 10GeV^2$. The higher helicity components in the twist-3 wave function will give an extra suppression to the pion form factor. The model dependence of the twist-3 contribution to the pion form factor has been studied by comparing three different models. When all the power contributions, which include higher order in $\alpha_s$, higher helicities, higher twists in DA and etc., have been taken into account, it is expected that the hard contributions will fit the present experimental data well at the energy region where pQCD is applicable.
hep-ph/9606463
Bruce Campbell
Rouzbeh Allahverdi and Bruce A. Campbell
Cosmological Reheating and Self-Interacting Final State Bosons
17 pages LaTeX, accepted for publication in Physics Letters B, extended discussion of broad-band resonance regime, and references added
Phys.Lett. B395 (1997) 169-177
10.1016/S0370-2693(97)00045-2
Alberta-THY-18/96
hep-ph
null
We consider inflaton decay to final state bosons with self-interactions of moderate strength. We find that such final state self-interactions qualitatively alter the reheat dynamics. In the case of narrow-band resonance decay, where a quantitative analysis is possible, we show that these final state interactions regulate the decay rate. The phenomenon of parametric amplification is then effectively suppressed, and does not drastically enhance the decay rate and reheat temperature. Detailed applications of our results to realistic classes of inflationary models will be considered elsewhere.
[ { "created": "Fri, 28 Jun 1996 04:02:30 GMT", "version": "v1" }, { "created": "Sun, 22 Dec 1996 20:46:58 GMT", "version": "v2" } ]
2009-10-28
[ [ "Allahverdi", "Rouzbeh", "" ], [ "Campbell", "Bruce A.", "" ] ]
We consider inflaton decay to final state bosons with self-interactions of moderate strength. We find that such final state self-interactions qualitatively alter the reheat dynamics. In the case of narrow-band resonance decay, where a quantitative analysis is possible, we show that these final state interactions regulate the decay rate. The phenomenon of parametric amplification is then effectively suppressed, and does not drastically enhance the decay rate and reheat temperature. Detailed applications of our results to realistic classes of inflationary models will be considered elsewhere.
2107.07840
Muhammad Waqas
M. Waqas, G. X. Peng, Z. Wazir
Decoupling of non-strange, strange and multi-strange particles from the system in Cu-Cu, Au-Au and Pb-Pb collisions at high energies
null
null
10.1016/j.cjph.2022.03.034
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Transverse momentum spectra of the non-strange, strange and multi-strange particles in central and peripheral Copper-Copper, Gold-Gold and Lead-Lead collisions are analyzed by the blast wave model with Boltzmann Gibbs statistics. The model results are approximately in agreement with the experimental data measured by BRAHMS, STAR, SPS, NA 49 and WA 97 Collaborations in special transverse momentum ranges. Bulk properties in terms of kinetic freeze out temperature, transverse flow velocity and freezeout volume are extracted from the transverse momentum spectra of the particles. Separate freeze out temperatures are observed for the non-strange, strange and multi-strange particles which maybe due to different reaction cross-sections of the interacting particles and it reveals the triple kinetic freezeout scenario in collisions at BRAHMS, STAR, SPS, NA 49 and WA 97 Collaborations, however the transverse flow velocity and freezeout volume are mass dependent and they decrease with the increasing the rest mass of the particles. Furthermore, the kinetic freezeout temperature, transverse flow velocity and kinetic freezeout volume in central nucleus-nucleus collisions are larger than those in peripheral collisions. Besides, the larger kinetic freezeout temperature and freezeout volume are observed in the most heaviest nuclei collisions, indicating their dependence on the size of interacting system
[ { "created": "Fri, 16 Jul 2021 12:00:36 GMT", "version": "v1" }, { "created": "Thu, 19 Aug 2021 15:24:04 GMT", "version": "v2" } ]
2022-05-04
[ [ "Waqas", "M.", "" ], [ "Peng", "G. X.", "" ], [ "Wazir", "Z.", "" ] ]
Transverse momentum spectra of the non-strange, strange and multi-strange particles in central and peripheral Copper-Copper, Gold-Gold and Lead-Lead collisions are analyzed by the blast wave model with Boltzmann Gibbs statistics. The model results are approximately in agreement with the experimental data measured by BRAHMS, STAR, SPS, NA 49 and WA 97 Collaborations in special transverse momentum ranges. Bulk properties in terms of kinetic freeze out temperature, transverse flow velocity and freezeout volume are extracted from the transverse momentum spectra of the particles. Separate freeze out temperatures are observed for the non-strange, strange and multi-strange particles which maybe due to different reaction cross-sections of the interacting particles and it reveals the triple kinetic freezeout scenario in collisions at BRAHMS, STAR, SPS, NA 49 and WA 97 Collaborations, however the transverse flow velocity and freezeout volume are mass dependent and they decrease with the increasing the rest mass of the particles. Furthermore, the kinetic freezeout temperature, transverse flow velocity and kinetic freezeout volume in central nucleus-nucleus collisions are larger than those in peripheral collisions. Besides, the larger kinetic freezeout temperature and freezeout volume are observed in the most heaviest nuclei collisions, indicating their dependence on the size of interacting system
2205.02250
Tongyan Lin
Brian Campbell-Deem, Simon Knapen, Tongyan Lin, Ethan Villarama
Dark matter direct detection from the single phonon to the nuclear recoil regime
28 pages, 16 figures; journal version with minor updates
null
10.1103/PhysRevD.106.036019
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
In most direct detection experiments, the free nuclear recoil description of dark matter scattering breaks down for masses $\lesssim$ 100 MeV, or when the recoil energy is comparable to a few times the typical phonon energy. For dark matter lighter than 1 MeV, scattering via excitation of a single phonon dominates and has been computed previously, but for the intermediate mass range or higher detector thresholds, multiphonon processes dominate. We perform the first calculation of the scattering rate via multiphonon production for the entire keV-GeV dark matter mass range, assuming a harmonic crystal target. We provide an analytic description that connects the single phonon, multiphonon, and the nuclear recoil regimes. Our results are implemented in the public package $\texttt{DarkELF}$.
[ { "created": "Wed, 4 May 2022 18:00:05 GMT", "version": "v1" }, { "created": "Fri, 25 Aug 2023 17:07:32 GMT", "version": "v2" } ]
2023-08-28
[ [ "Campbell-Deem", "Brian", "" ], [ "Knapen", "Simon", "" ], [ "Lin", "Tongyan", "" ], [ "Villarama", "Ethan", "" ] ]
In most direct detection experiments, the free nuclear recoil description of dark matter scattering breaks down for masses $\lesssim$ 100 MeV, or when the recoil energy is comparable to a few times the typical phonon energy. For dark matter lighter than 1 MeV, scattering via excitation of a single phonon dominates and has been computed previously, but for the intermediate mass range or higher detector thresholds, multiphonon processes dominate. We perform the first calculation of the scattering rate via multiphonon production for the entire keV-GeV dark matter mass range, assuming a harmonic crystal target. We provide an analytic description that connects the single phonon, multiphonon, and the nuclear recoil regimes. Our results are implemented in the public package $\texttt{DarkELF}$.
1612.08822
Chen Cheng
Chen Cheng, Xiao-Yun Wang
The production of neutral $N^*(11052)$ resonance with hidden beauty from $\pi^-p$ scattering
null
Adv. High Energy Phys. 2017 (2017) 9398732
10.1155/2017/9398732
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate the discovery potential of the predicted neutral hidden beauty $N^*(11052)$ resonance through $\pi^- p$ scattering within an effective Lagrangian approach. Two reactions $\pi^-p\rightarrow K^-\Sigma^+$ and $\pi^-p\rightarrow \eta_bn$ are studied in this work, with nucleon pole exchange as the background. It is found that the contributions of the $N^*(11052)$ resonance give clear peak structures in the magnitude of 1 $\mu b$ near the threshold of the $N^*(11052)$ in the total cross sections. The numerical results indicate that the center of mass energy $W\simeq$ 11-11.1 GeV would be a best energy window for searching the $N^*(11052)$ resonance, where the $N^*(11052)$ signal can be easily distinguished from the background. The COMPASS experiment at CERN's Super Proton Synchrotron (SPS) with pion beam of $\simeq$ 280 GeV will be an ideal platform for searching the super-heavy resonance with hidden beauty, which is hopeful to test the theoretical results.
[ { "created": "Wed, 28 Dec 2016 08:13:13 GMT", "version": "v1" } ]
2017-01-06
[ [ "Cheng", "Chen", "" ], [ "Wang", "Xiao-Yun", "" ] ]
We investigate the discovery potential of the predicted neutral hidden beauty $N^*(11052)$ resonance through $\pi^- p$ scattering within an effective Lagrangian approach. Two reactions $\pi^-p\rightarrow K^-\Sigma^+$ and $\pi^-p\rightarrow \eta_bn$ are studied in this work, with nucleon pole exchange as the background. It is found that the contributions of the $N^*(11052)$ resonance give clear peak structures in the magnitude of 1 $\mu b$ near the threshold of the $N^*(11052)$ in the total cross sections. The numerical results indicate that the center of mass energy $W\simeq$ 11-11.1 GeV would be a best energy window for searching the $N^*(11052)$ resonance, where the $N^*(11052)$ signal can be easily distinguished from the background. The COMPASS experiment at CERN's Super Proton Synchrotron (SPS) with pion beam of $\simeq$ 280 GeV will be an ideal platform for searching the super-heavy resonance with hidden beauty, which is hopeful to test the theoretical results.
1404.3670
Ralf Lehnert
Ralf Lehnert
Spacetime-symmetry violations: motivations, phenomenology, and tests
10 pages, 1 figure
Physics Procedia 17, 135 (2011)
10.1016/j.phpro.2011.06.029
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
An important open question in fundamental physics concerns the nature of spacetime at distance scales associated with the Planck length. The widespread belief that probing such distances necessitates Planck-energy particles has impeded phenomenological and experimental research in this context. However, it has been realized that various theoretical approaches to underlying physics can accommodate Planck-scale violations of spacetime symmetries. This talk surveys the motivations for spacetime-symmetry research, the SME test framework, and experimental efforts in this field.
[ { "created": "Mon, 14 Apr 2014 17:57:36 GMT", "version": "v1" } ]
2014-04-15
[ [ "Lehnert", "Ralf", "" ] ]
An important open question in fundamental physics concerns the nature of spacetime at distance scales associated with the Planck length. The widespread belief that probing such distances necessitates Planck-energy particles has impeded phenomenological and experimental research in this context. However, it has been realized that various theoretical approaches to underlying physics can accommodate Planck-scale violations of spacetime symmetries. This talk surveys the motivations for spacetime-symmetry research, the SME test framework, and experimental efforts in this field.
0802.0769
Allen Caldwell
Allen Caldwell
Behavior of sigma(gamma p) at Large Coherence Lengths
34 pages, 20 figures
null
null
null
hep-ph
null
Various parametrizations of sigma(gamma p) are tried out on the small-x fixed target and HERA data. A two-Pomeron type parametrization is found to give the best reproduction of the data. The data indicate that the value of lambda(eff) for parametrizations of the form sigma(gamma p)~l^lambda(eff) approaches a constant value at high Q^2. The extrapolated values of sigma(gamma p) to very long coherence lengths are found to cross in some parametrizations for l>10^7 fm, indicating the possibility that sigma(gamma p) becomes Q^2 independent at large values of the coherence length l.
[ { "created": "Wed, 6 Feb 2008 12:56:51 GMT", "version": "v1" } ]
2008-02-07
[ [ "Caldwell", "Allen", "" ] ]
Various parametrizations of sigma(gamma p) are tried out on the small-x fixed target and HERA data. A two-Pomeron type parametrization is found to give the best reproduction of the data. The data indicate that the value of lambda(eff) for parametrizations of the form sigma(gamma p)~l^lambda(eff) approaches a constant value at high Q^2. The extrapolated values of sigma(gamma p) to very long coherence lengths are found to cross in some parametrizations for l>10^7 fm, indicating the possibility that sigma(gamma p) becomes Q^2 independent at large values of the coherence length l.
2104.07670
Samuel Witte
Samuel J. Witte, Dion Noordhuis, Thomas D. P. Edwards, and Christoph Weniger
Axion-Photon Conversion in Neutron Star Magnetospheres: The Role of the Plasma in the Goldreich-Julian Model
v3: Fix "?" citation. v2: Accepted for publication PRD. Convergence improved, plots updated, minor bugs and typos corrected. No major changes to results/conclusions. v1: 9 pages + Appendix
null
10.1103/PhysRevD.104.103030
null
hep-ph astro-ph.CO astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The most promising indirect search for the existence of axion dark matter uses radio telescopes to look for narrow spectral lines generated from the resonant conversion of axions in the magnetospheres of neutron stars. Unfortunately, a large list of theoretical uncertainties has prevented this search strategy from being fully accepted as robust. In this work we attempt to address major outstanding questions related to the role and impact of the plasma, including: $(i)$ does refraction and reflection of radio photons in the magnetosphere induce strong inhomogeneities in the flux, $(ii)$ can refraction induce premature axion-photon de-phasing, $(iii)$ to what extent do photon-plasma interactions induce a broadening of the spectral line, $(iv)$ does the flux have a strong time dependence, and $(v)$ can radio photons sourced by axions be absorbed by the plasma. We present an end-to-end analysis pipeline based on ray-tracing that exploits a state-of-the-art auto-differentiation algorithm to propagate photons from the conversion surface to asymptotically large distances. Adopting a charge symmetric Goldreich-Julian model for the magnetosphere, we show that for reasonable parameters one should expect a strong anisotropy of the signal, refraction induced axion-photon de-phasing, significant line-broadening, a variable time-dependence of the flux, and, for large enough magnetic fields, anisotropic absorption. Our simulation code is flexible enough to serve as the basis for follow-up studies with a large range of magnetosphere models.
[ { "created": "Thu, 15 Apr 2021 18:00:00 GMT", "version": "v1" }, { "created": "Tue, 2 Nov 2021 08:34:03 GMT", "version": "v2" }, { "created": "Mon, 4 Jul 2022 13:50:06 GMT", "version": "v3" } ]
2022-07-05
[ [ "Witte", "Samuel J.", "" ], [ "Noordhuis", "Dion", "" ], [ "Edwards", "Thomas D. P.", "" ], [ "Weniger", "Christoph", "" ] ]
The most promising indirect search for the existence of axion dark matter uses radio telescopes to look for narrow spectral lines generated from the resonant conversion of axions in the magnetospheres of neutron stars. Unfortunately, a large list of theoretical uncertainties has prevented this search strategy from being fully accepted as robust. In this work we attempt to address major outstanding questions related to the role and impact of the plasma, including: $(i)$ does refraction and reflection of radio photons in the magnetosphere induce strong inhomogeneities in the flux, $(ii)$ can refraction induce premature axion-photon de-phasing, $(iii)$ to what extent do photon-plasma interactions induce a broadening of the spectral line, $(iv)$ does the flux have a strong time dependence, and $(v)$ can radio photons sourced by axions be absorbed by the plasma. We present an end-to-end analysis pipeline based on ray-tracing that exploits a state-of-the-art auto-differentiation algorithm to propagate photons from the conversion surface to asymptotically large distances. Adopting a charge symmetric Goldreich-Julian model for the magnetosphere, we show that for reasonable parameters one should expect a strong anisotropy of the signal, refraction induced axion-photon de-phasing, significant line-broadening, a variable time-dependence of the flux, and, for large enough magnetic fields, anisotropic absorption. Our simulation code is flexible enough to serve as the basis for follow-up studies with a large range of magnetosphere models.
hep-ph/9712340
Jonathan R. Ellis
John Ellis
Hunting Down Interpretations of the HERA Large-Q^2 data
8 pages, Latex, Parallel Session Talk presented at Europhysics Conference on High-Energy Physics, Jerusalem, August 1997
null
null
CERN-TH/97-356
hep-ph
null
Possible interpretations of the HERA large-Q^2 data are reviewed briefly. The possibility of statistical fluctuations cannot be ruled out, and it seems premature to argue that the H1 and ZEUS anomalies are incompatible. The data cannot be explained away by modifications of parton distributions, nor do contact interactions help. A leptoquark interpretation would need a large tau-q branching ratio. Several R-violating squark interpretations are still viable despite all the constraints, and offer interesting experimental signatures, but please do not hold your breath.
[ { "created": "Thu, 11 Dec 1997 09:29:11 GMT", "version": "v1" } ]
2007-05-23
[ [ "Ellis", "John", "" ] ]
Possible interpretations of the HERA large-Q^2 data are reviewed briefly. The possibility of statistical fluctuations cannot be ruled out, and it seems premature to argue that the H1 and ZEUS anomalies are incompatible. The data cannot be explained away by modifications of parton distributions, nor do contact interactions help. A leptoquark interpretation would need a large tau-q branching ratio. Several R-violating squark interpretations are still viable despite all the constraints, and offer interesting experimental signatures, but please do not hold your breath.
1411.7392
Robert Schabinger
Andreas von Manteuffel, Erik Panzer, and Robert M. Schabinger
A quasi-finite basis for multi-loop Feynman integrals
21 pages, 3 figures; in v2: added additional references. v2 is the version published in JHEP; in v3: fixed references
Journal of High Energy Physics, February 2015:120
10.1007/JHEP02(2015)120
MITP/14-076
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a new method for the decomposition of multi-loop Euclidean Feynman integrals into quasi-finite Feynman integrals. These are defined in shifted dimensions with higher powers of the propagators, make explicit both infrared and ultraviolet divergences, and allow for an immediate and trivial expansion in the parameter of dimensional regularization. Our approach avoids the introduction of spurious structures and thereby leaves integrals particularly accessible to direct analytical integration techniques. Alternatively, the resulting convergent Feynman parameter integrals may be evaluated numerically. Our approach is guided by previous work by the second author but overcomes practical limitations of the original procedure by employing integration by parts reduction.
[ { "created": "Wed, 26 Nov 2014 21:00:52 GMT", "version": "v1" }, { "created": "Wed, 23 Sep 2015 14:18:18 GMT", "version": "v2" }, { "created": "Thu, 20 Apr 2017 14:49:58 GMT", "version": "v3" } ]
2017-04-21
[ [ "von Manteuffel", "Andreas", "" ], [ "Panzer", "Erik", "" ], [ "Schabinger", "Robert M.", "" ] ]
We present a new method for the decomposition of multi-loop Euclidean Feynman integrals into quasi-finite Feynman integrals. These are defined in shifted dimensions with higher powers of the propagators, make explicit both infrared and ultraviolet divergences, and allow for an immediate and trivial expansion in the parameter of dimensional regularization. Our approach avoids the introduction of spurious structures and thereby leaves integrals particularly accessible to direct analytical integration techniques. Alternatively, the resulting convergent Feynman parameter integrals may be evaluated numerically. Our approach is guided by previous work by the second author but overcomes practical limitations of the original procedure by employing integration by parts reduction.
1111.4308
Andrej Arbuzov
Andrej B. Arbuzov and Tatiana V. Kopylova
On relativization of the Sommerfeld-Gamow-Sakharov factor
9 pages, 4 figures; references and discussion are extended
null
10.1007/JHEP04(2012)009
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Sommerfeld-Gamow-Sakharov factor is considered for the general case of arbitrary masses and energies. It is shown that the scalar triangular one-loop diagram gives the Coulomb singularity in radiative corrections at the threshold. The singular part of the correction is factorized at the complete Born cross section regardless of its partial wave decomposition. Different approaches to generalize the factor are discussed.
[ { "created": "Fri, 18 Nov 2011 09:18:09 GMT", "version": "v1" }, { "created": "Fri, 25 Nov 2011 10:18:24 GMT", "version": "v2" } ]
2015-06-03
[ [ "Arbuzov", "Andrej B.", "" ], [ "Kopylova", "Tatiana V.", "" ] ]
The Sommerfeld-Gamow-Sakharov factor is considered for the general case of arbitrary masses and energies. It is shown that the scalar triangular one-loop diagram gives the Coulomb singularity in radiative corrections at the threshold. The singular part of the correction is factorized at the complete Born cross section regardless of its partial wave decomposition. Different approaches to generalize the factor are discussed.
1504.07008
Peter Filip
Peter Filip
Decay of Resonaces in Strong Magnetic Field
10 pages, 6 figures, contribution to WWND-2015 conference proceedings
Journal of Physics: Conference Series 636 (2015) 012013
10.1088/1742-6596/636/1/012013
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We suggest that decay properties (branching ratios) of hadronic resonances may become modified in strong external magnetic field. The behavior of $K^{\pm *}\!$, $K^{0*}$ vector mesons as well as $\Lambda^*(1520)$ and $\Xi^{0*}$ baryonic states is considered in static fields $10^{13}$-\,$10^{15}$ T. In particular, $n=0$ Landau level energy increase of charged particles in the external magnetic field, and the interaction of hadron magnetic moments with the field is taken into account. We suggest that enhanced yield of dileptons and photons from $\rho^0(770)$ mesons may occur if strong decay channel $\rho^0 \rightarrow \pi^+\pi^-$ is significantly suppressed. CP - violating $\pi^+\pi^-$ decays of pseudoscalar $\eta_c$ and $\eta(547)$ mesons in the magnetic field are discussed, and superpositions of quarkonium states $\eta_{c,b}$ and $\chi_{c,b}(nP)$ with $\Psi(nS), \Upsilon(nS)$ mesons in the external field are considered.
[ { "created": "Mon, 27 Apr 2015 10:00:20 GMT", "version": "v1" } ]
2015-09-01
[ [ "Filip", "Peter", "" ] ]
We suggest that decay properties (branching ratios) of hadronic resonances may become modified in strong external magnetic field. The behavior of $K^{\pm *}\!$, $K^{0*}$ vector mesons as well as $\Lambda^*(1520)$ and $\Xi^{0*}$ baryonic states is considered in static fields $10^{13}$-\,$10^{15}$ T. In particular, $n=0$ Landau level energy increase of charged particles in the external magnetic field, and the interaction of hadron magnetic moments with the field is taken into account. We suggest that enhanced yield of dileptons and photons from $\rho^0(770)$ mesons may occur if strong decay channel $\rho^0 \rightarrow \pi^+\pi^-$ is significantly suppressed. CP - violating $\pi^+\pi^-$ decays of pseudoscalar $\eta_c$ and $\eta(547)$ mesons in the magnetic field are discussed, and superpositions of quarkonium states $\eta_{c,b}$ and $\chi_{c,b}(nP)$ with $\Psi(nS), \Upsilon(nS)$ mesons in the external field are considered.
hep-ph/9802407
null
Marco Aurelio Diaz
Bilinear R-Parity Violation
12 pages, including 5 figures, Latex. To appear in the proceedings of the International Workshop "Beyond the Standard Model: From Theory to Experiment", 13-17 October 1997, Valencia, Spain
null
null
IFIC/98-11, FTUV/98-11
hep-ph
null
We review some of the main features of Bilinear R-Parity Violation (BRpV), defined by a quadratic term in the superpotential which mixes lepton and Higgs superfields and is proportional to a mass parameter epsilon. We show how large values of epsilon can induce a small neutrino mass without fine-tunning. We mention the effect on the mass of the lightest Higgs boson. Finally we report on the effect of BRpV on gauge and Yukawa unification, showing that bottom-tau unification can be achieved at any value of tan(beta).
[ { "created": "Tue, 24 Feb 1998 13:20:44 GMT", "version": "v1" } ]
2007-05-23
[ [ "Diaz", "Marco Aurelio", "" ] ]
We review some of the main features of Bilinear R-Parity Violation (BRpV), defined by a quadratic term in the superpotential which mixes lepton and Higgs superfields and is proportional to a mass parameter epsilon. We show how large values of epsilon can induce a small neutrino mass without fine-tunning. We mention the effect on the mass of the lightest Higgs boson. Finally we report on the effect of BRpV on gauge and Yukawa unification, showing that bottom-tau unification can be achieved at any value of tan(beta).
1601.03566
Hyun Min Lee
Soo-Min Choi, Hyun Min Lee
Resonant SIMP dark matter
14 pages, 5 figures, Improved discussion on thermal-averaged annihilation cross section
null
10.1016/j.physletb.2016.04.055
null
hep-ph astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider a resonant SIMP dark matter in models with two singlet complex scalar fields charged under a local dark $U(1)_D$. After the $U(1)_D$ is broken down to a $Z_5$ discrete subgroup, the lighter scalar field becomes a SIMP dark matter which has the enhanced $3\rightarrow 2$ annihilation cross section near the resonance of the heavier scalar field. Bounds on the SIMP self-scattering cross section and the relic density can be fulfilled at the same time for perturbative couplings of SIMP. A small gauge kinetic mixing between the SM hypercharge and dark gauge bosons can be used to make SIMP dark matter in kinetic equilibrium with the SM during freeze-out.
[ { "created": "Thu, 14 Jan 2016 11:50:20 GMT", "version": "v1" }, { "created": "Wed, 2 Mar 2016 14:45:50 GMT", "version": "v2" } ]
2016-06-22
[ [ "Choi", "Soo-Min", "" ], [ "Lee", "Hyun Min", "" ] ]
We consider a resonant SIMP dark matter in models with two singlet complex scalar fields charged under a local dark $U(1)_D$. After the $U(1)_D$ is broken down to a $Z_5$ discrete subgroup, the lighter scalar field becomes a SIMP dark matter which has the enhanced $3\rightarrow 2$ annihilation cross section near the resonance of the heavier scalar field. Bounds on the SIMP self-scattering cross section and the relic density can be fulfilled at the same time for perturbative couplings of SIMP. A small gauge kinetic mixing between the SM hypercharge and dark gauge bosons can be used to make SIMP dark matter in kinetic equilibrium with the SM during freeze-out.
hep-ph/9709285
Anupam Singh
Edward W. Kolb, Anupam Singh and Mark Srednicki
Quantum Fluctuations of Axions
Revtex, 15 pages including epsf figures, final version to appear in Phys. Rev. D: now contains a detailed discussion taking into account the time dependence of the axion mass; conclusions unchanged
Phys.Rev. D58 (1998) 105004
10.1103/PhysRevD.58.105004
null
hep-ph astro-ph gr-qc hep-th
null
We study the time evolution of the quantum fluctuations of the axion field for both the QCD axion as well as axions arising in the context of supergravity and string theories. We explicitly keep track not only of the coherently oscillating zero momentum mode of the axion but also of the higher non-zero momentum modes using the full axion potential. The full axion potential makes possible two kinds of instabilities: spinodal instabilities and parametric resonance instabilities. The presence of either of these instabilities can lead to a quasi-exponential increase in the occupation of non-zero momentum modes and the build-up of the quantum fluctuations of the axions. If either of these becomes a significant effect then axions would no longer be a suitable cold dark matter candidate. Our results confirm the conventional wisdom that these effects are not significant in the setting of an expanding FRW universe and hence axions are indeed cold dark matter candidates.
[ { "created": "Mon, 8 Sep 1997 18:28:23 GMT", "version": "v1" }, { "created": "Tue, 28 Jul 1998 21:21:30 GMT", "version": "v2" } ]
2009-10-30
[ [ "Kolb", "Edward W.", "" ], [ "Singh", "Anupam", "" ], [ "Srednicki", "Mark", "" ] ]
We study the time evolution of the quantum fluctuations of the axion field for both the QCD axion as well as axions arising in the context of supergravity and string theories. We explicitly keep track not only of the coherently oscillating zero momentum mode of the axion but also of the higher non-zero momentum modes using the full axion potential. The full axion potential makes possible two kinds of instabilities: spinodal instabilities and parametric resonance instabilities. The presence of either of these instabilities can lead to a quasi-exponential increase in the occupation of non-zero momentum modes and the build-up of the quantum fluctuations of the axions. If either of these becomes a significant effect then axions would no longer be a suitable cold dark matter candidate. Our results confirm the conventional wisdom that these effects are not significant in the setting of an expanding FRW universe and hence axions are indeed cold dark matter candidates.
1104.0083
Jing Shu
Jing Shu, Kai Wang and Guohuai Zhu
A Revisit to Top Quark Forward-Backward Asymmetry
25 pages, 7 figures, 1 table
null
10.1103/PhysRevD.85.034008
IPMU11-0050
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We analyze various models for the top quark forward-backward asymmetry ($A^t_{FB}$) at the Tevatron, using the latest CDF measurements on different $A^t_{FB}$s and the total cross section. The axigluon model in Ref. \cite{paul} has difficulties in explaining the large rapidity dependent asymmetry and mass dependent asymmetry simultaneously and the parameter space relevant to $A^t_{FB}$ is ruled out by the latest dijet search at ATLAS. In contrast to Ref. \cite{cp}, we demonstrate that the large parameter space in this model with a $U(1)_d$ flavor symemtry is not ruled out by flavor physics. The $t$-channel flavor-violating $Z^{\prime}$ \cite{hitoshi}, $W^{\prime}$\cite{waiyee} and diquark \cite{tim} models all have parameter regions that satisfy different $A_{FB}$ measurements within 1 $\sigma$. However, the heavy $Z^{\prime}$ model which can be marginally consistent with the total cross section is severely constrained by the Tevatron direct search of same-sign top quark pair. The diquark model suffers from too large total cross section and is difficult to fit the $t \bar{t}$ invariant mass distribution. The electroweak precision constraints on the $W'$ model based on $Z'$-$Z$ mixings is estimated and the result is rather weak ($m_{Z'} > 450$ GeV). Therefore, the heavy $W^{\prime}$ model seems to give the best fit for all the measurements. The $W^{\prime}$ model predicts the $t\bar{t}+j$ signal from $tW^{\prime}$ production and is 10%-50% of SM $t\bar{t}$ at the 7 TeV LHC. Such $t+j$ resonance can serve as the direct test of the $W^{\prime}$ model.
[ { "created": "Fri, 1 Apr 2011 06:02:13 GMT", "version": "v1" } ]
2015-05-27
[ [ "Shu", "Jing", "" ], [ "Wang", "Kai", "" ], [ "Zhu", "Guohuai", "" ] ]
We analyze various models for the top quark forward-backward asymmetry ($A^t_{FB}$) at the Tevatron, using the latest CDF measurements on different $A^t_{FB}$s and the total cross section. The axigluon model in Ref. \cite{paul} has difficulties in explaining the large rapidity dependent asymmetry and mass dependent asymmetry simultaneously and the parameter space relevant to $A^t_{FB}$ is ruled out by the latest dijet search at ATLAS. In contrast to Ref. \cite{cp}, we demonstrate that the large parameter space in this model with a $U(1)_d$ flavor symemtry is not ruled out by flavor physics. The $t$-channel flavor-violating $Z^{\prime}$ \cite{hitoshi}, $W^{\prime}$\cite{waiyee} and diquark \cite{tim} models all have parameter regions that satisfy different $A_{FB}$ measurements within 1 $\sigma$. However, the heavy $Z^{\prime}$ model which can be marginally consistent with the total cross section is severely constrained by the Tevatron direct search of same-sign top quark pair. The diquark model suffers from too large total cross section and is difficult to fit the $t \bar{t}$ invariant mass distribution. The electroweak precision constraints on the $W'$ model based on $Z'$-$Z$ mixings is estimated and the result is rather weak ($m_{Z'} > 450$ GeV). Therefore, the heavy $W^{\prime}$ model seems to give the best fit for all the measurements. The $W^{\prime}$ model predicts the $t\bar{t}+j$ signal from $tW^{\prime}$ production and is 10%-50% of SM $t\bar{t}$ at the 7 TeV LHC. Such $t+j$ resonance can serve as the direct test of the $W^{\prime}$ model.
hep-ph/0203060
yongjin Jiang
Guang-jiong Ni
Superluminal Paradox and Neutrino
null
null
null
null
hep-ph
null
Einstein's theory of special relativity(SR) and the principle of causality imply that the speed of any moving object can not exceed that of light in a vacuum($c$).However,there were many attempts in literature discussing the particle moving with speed $u>c$(called as superluminal particle or tachyon)either in the scheme of SR or beyond it.These theories all encountered a series of insurmountable difficulties which will be named ``superluminal paradox''in this paper.We will analyze it in some detail and then prove that the paradox disappears unambiguously in quantum theory,which is compatible with SR.Most likely,the superluminal particle in real world is just a kind of known particle,the neutrino.
[ { "created": "Wed, 6 Mar 2002 08:27:34 GMT", "version": "v1" } ]
2007-05-23
[ [ "Ni", "Guang-jiong", "" ] ]
Einstein's theory of special relativity(SR) and the principle of causality imply that the speed of any moving object can not exceed that of light in a vacuum($c$).However,there were many attempts in literature discussing the particle moving with speed $u>c$(called as superluminal particle or tachyon)either in the scheme of SR or beyond it.These theories all encountered a series of insurmountable difficulties which will be named ``superluminal paradox''in this paper.We will analyze it in some detail and then prove that the paradox disappears unambiguously in quantum theory,which is compatible with SR.Most likely,the superluminal particle in real world is just a kind of known particle,the neutrino.
1708.07348
Kazem Azizi
S. S. Agaev, K. Azizi, H. Sundu
Decay widths of the excited $\Omega_b$ baryons
17 Pages, 8 Figures and 1 Table
null
10.1103/PhysRevD.96.094011
null
hep-ph hep-ex hep-lat
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The LHCb Collaboration recently observed five narrow $\Omega_c^{0}$ resonances, and measured their masses and widths through the decays $ \Omega_c^{0} \to \Xi_c^{+}K^{-}$. Motivated by this discovery, and also by the fact that the ground-state bottom baryon $\Omega_b^{-}$ with spin-1/2 was already found experimentally, we perform theoretical investigation of the spin-1/2 and spin-3/2, $\Omega_b$, baryons by calculating decay width of their first orbitally and radially excited states to $\Xi_b^{0} K^{-}$. For this purpose, we employ QCD sum rule method on the light-cone by including into analysis the $K$ meson distribution amplitudes up to twist-4. Obtained analytical expressions are utilized to extract parameters of these decay processes which may be useful for forthcoming experimental studies of bottom baryons.
[ { "created": "Thu, 24 Aug 2017 10:43:11 GMT", "version": "v1" }, { "created": "Mon, 23 Oct 2017 14:24:41 GMT", "version": "v2" } ]
2022-08-17
[ [ "Agaev", "S. S.", "" ], [ "Azizi", "K.", "" ], [ "Sundu", "H.", "" ] ]
The LHCb Collaboration recently observed five narrow $\Omega_c^{0}$ resonances, and measured their masses and widths through the decays $ \Omega_c^{0} \to \Xi_c^{+}K^{-}$. Motivated by this discovery, and also by the fact that the ground-state bottom baryon $\Omega_b^{-}$ with spin-1/2 was already found experimentally, we perform theoretical investigation of the spin-1/2 and spin-3/2, $\Omega_b$, baryons by calculating decay width of their first orbitally and radially excited states to $\Xi_b^{0} K^{-}$. For this purpose, we employ QCD sum rule method on the light-cone by including into analysis the $K$ meson distribution amplitudes up to twist-4. Obtained analytical expressions are utilized to extract parameters of these decay processes which may be useful for forthcoming experimental studies of bottom baryons.
1810.07955
Nicolas Wink
Reinhard Alkofer, Axel Maas, Walid Ahmed Mian, Mario Mitter, Jordi Par\'is-L\'opez, Jan M. Pawlowski, Nicolas Wink
Bound state properties from the Functional Renormalisation Group
Version submitted to Journal
Phys. Rev. D 99, 054029 (2019)
10.1103/PhysRevD.99.054029
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We discuss an approach for accessing bound state properties, like mass and decay width, of a theory within the functional renormalisation group approach. An important cornerstone is the dynamical hadronization technique for resonant interaction channels. The general framework is exemplified and put to work within the two-flavour quark-meson model. This model provides a low-energy description of the dynamics of two-flavour QCD with quark and hadronic degrees of freedom. We compare explicitly the respective results for correlation functions and observables with first principle QCD results in a quantitative manner. This allows us to estimate the validity range of low energy effective models. We also present first results for pole masses and decay widths. Next steps involving real-time formulations of the functional renormalisation group are discussed.
[ { "created": "Thu, 18 Oct 2018 09:06:49 GMT", "version": "v1" }, { "created": "Thu, 8 Nov 2018 14:36:37 GMT", "version": "v2" } ]
2019-04-03
[ [ "Alkofer", "Reinhard", "" ], [ "Maas", "Axel", "" ], [ "Mian", "Walid Ahmed", "" ], [ "Mitter", "Mario", "" ], [ "París-López", "Jordi", "" ], [ "Pawlowski", "Jan M.", "" ], [ "Wink", "Nicolas", "" ] ]
We discuss an approach for accessing bound state properties, like mass and decay width, of a theory within the functional renormalisation group approach. An important cornerstone is the dynamical hadronization technique for resonant interaction channels. The general framework is exemplified and put to work within the two-flavour quark-meson model. This model provides a low-energy description of the dynamics of two-flavour QCD with quark and hadronic degrees of freedom. We compare explicitly the respective results for correlation functions and observables with first principle QCD results in a quantitative manner. This allows us to estimate the validity range of low energy effective models. We also present first results for pole masses and decay widths. Next steps involving real-time formulations of the functional renormalisation group are discussed.
hep-ph/0311182
Nestor Armesto
N. Armesto
Introduction to Low x Physics and Saturation
8 pages in LaTeX using enclosed appolb.cls, 3 eps figures included using epsfig; minireview at the XXXIIIrd International Symposium on Multiparticle Dynamics (Kracow, Poland, September 5th-11th 2003)
Acta Phys.Polon. B35 (2004) 213-222
null
CERN-TH/2003-278
hep-ph
null
The idea of saturation of parton densities in small x physics is briefly introduced. Some aspects of saturation are described, mainly focusing on the status of our knowledge on the non-linear equations describing the high parton density regime. Implications of saturation ideas on the description of nuclear collisions at the Relativistic Heavy Ion Collider are discussed.
[ { "created": "Fri, 14 Nov 2003 09:31:26 GMT", "version": "v1" } ]
2007-05-23
[ [ "Armesto", "N.", "" ] ]
The idea of saturation of parton densities in small x physics is briefly introduced. Some aspects of saturation are described, mainly focusing on the status of our knowledge on the non-linear equations describing the high parton density regime. Implications of saturation ideas on the description of nuclear collisions at the Relativistic Heavy Ion Collider are discussed.
1109.0661
Gilberto Tavares-Velasco
I. Cortes-Maldonado (Facultad de Ciencias Fisico Matematicas, Benemerita Universidad Autonoma de Puebla), A. Moyotl (Instituto de Fisica, Benemerita Universidad Autonoma de Puebla), G. Tavares-Velasco (Facultad de Ciencias Fisico Matematicas, Benemerita Universidad Autonoma de Puebla)
Lepton flavor violating decay Z-> l_i l_j in the 331 model
14 pages, 3 figures, 1 table
null
10.1142/S0217751X11054474
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the lepton flavor violating (LFV) decays Z-> l_i l_j (l_{i,j}=e,\mu,\tau) in the framework of the minimal 331 model. The main contributions arise at the one-loop level via a doubly charged bilepton with general LFV couplings. We obtain an estimate for the corresponding branching ratios by using the bounds on the LFV couplings of the doubly charged bilepton from the current experimental limits on the decays l_i-> l_j\gamma and l_i-> l_j l_k l_k. A bound on the bilepton mass is also obtained through the current limit on the anomalous magnetic moment of the muon. It is found that the bilepton contributions to LFV Z decays are not expected to be at the reach of experimental detection. In particular, the branching ratio for the Z-> \mu \tau decay is below the 10^{-10} level for a bilepton mass of the order of 500 GeV.
[ { "created": "Sun, 4 Sep 2011 01:06:58 GMT", "version": "v1" } ]
2011-09-29
[ [ "Cortes-Maldonado", "I.", "", "Facultad de Ciencias Fisico Matematicas,\n Benemerita Universidad Autonoma de Puebla" ], [ "Moyotl", "A.", "", "Instituto de Fisica,\n Benemerita Universidad Autonoma de Puebla" ], [ "Tavares-Velasco", "G.", "", "Facultad de\n Ciencias Fisico Matematicas, Benemerita Universidad Autonoma de Puebla" ] ]
We study the lepton flavor violating (LFV) decays Z-> l_i l_j (l_{i,j}=e,\mu,\tau) in the framework of the minimal 331 model. The main contributions arise at the one-loop level via a doubly charged bilepton with general LFV couplings. We obtain an estimate for the corresponding branching ratios by using the bounds on the LFV couplings of the doubly charged bilepton from the current experimental limits on the decays l_i-> l_j\gamma and l_i-> l_j l_k l_k. A bound on the bilepton mass is also obtained through the current limit on the anomalous magnetic moment of the muon. It is found that the bilepton contributions to LFV Z decays are not expected to be at the reach of experimental detection. In particular, the branching ratio for the Z-> \mu \tau decay is below the 10^{-10} level for a bilepton mass of the order of 500 GeV.
0912.2660
Jacopo Bechi
Jacopo Bechi
Statistical Hadronization and Holography
null
null
null
CP3-Origins: 2009-27
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper we consider some issues about the statistical model of the hadronization in a holographic approach. We introduce a Rindler like horizon in the bulk and we understand the string breaking as a tunneling event under this horizon. We calculate the hadron spectrum and we get a thermal, and so statistical, shape for it.
[ { "created": "Mon, 14 Dec 2009 15:14:51 GMT", "version": "v1" }, { "created": "Thu, 17 Dec 2009 14:37:23 GMT", "version": "v2" } ]
2009-12-17
[ [ "Bechi", "Jacopo", "" ] ]
In this paper we consider some issues about the statistical model of the hadronization in a holographic approach. We introduce a Rindler like horizon in the bulk and we understand the string breaking as a tunneling event under this horizon. We calculate the hadron spectrum and we get a thermal, and so statistical, shape for it.
0906.4231
Hannu Paukkunen
Kari J. Eskola, Hannu Paukkunen, Carlos A. Salgado
EPS09 - Nuclear PDFs and Their Uncertainties at NLO
4 pages, 4 figures - To appear in the conference proceedings for Quark Matter 2009, March 30 - April 4, Knoxville, Tennessee
Nucl.Phys.A830:599c-602c,2009
10.1016/j.nuclphysa.2009.10.054
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this talk, we present our recent next-to-leading order (NLO) nuclear parton distribution functions (nPDFs), which we call EPS09. As an extension to earlier NLO analyses, we supplement the deep inelastic scattering and Drell-Yan dilepton data by inclusive midrapidity pion measurements from RHIC in order to reduce the otherwize large freedom in the nuclear gluon densities. Our Hessian-type error analysis leading to a collection of nPDF error sets, is the first of its kind among the nPDF analyses.
[ { "created": "Tue, 23 Jun 2009 11:41:18 GMT", "version": "v1" }, { "created": "Mon, 21 Sep 2009 08:23:58 GMT", "version": "v2" } ]
2009-11-18
[ [ "Eskola", "Kari J.", "" ], [ "Paukkunen", "Hannu", "" ], [ "Salgado", "Carlos A.", "" ] ]
In this talk, we present our recent next-to-leading order (NLO) nuclear parton distribution functions (nPDFs), which we call EPS09. As an extension to earlier NLO analyses, we supplement the deep inelastic scattering and Drell-Yan dilepton data by inclusive midrapidity pion measurements from RHIC in order to reduce the otherwize large freedom in the nuclear gluon densities. Our Hessian-type error analysis leading to a collection of nPDF error sets, is the first of its kind among the nPDF analyses.
0803.2664
Florian Bauer
Florian Bauer and Durmus A. Demir
Inflation with Non-Minimal Coupling: Metric vs. Palatini Formulations
13 pages, reference added
Phys.Lett.B665:222-226,2008
10.1016/j.physletb.2008.06.014
DESY 08-033, IZTECH-P-08/02
hep-ph astro-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We analyze non-minimally coupled scalar field theories in metric (second-order) and Palatini (first-order) formalisms in a comparative fashion. After contrasting them in a general setup, we specialize to inflation and find that the two formalisms differ in their predictions for various cosmological parameters. The main reason is that dependencies on the non-minimal coupling parameter are different in the two formalisms. For successful inflation, the Palatini approach prefers a much larger value for the non-minimal coupling parameter than the Metric approach. Unlike the Metric formalism, in Palatini, the inflaton stays well below the Planck scale whereby providing a natural inflationary epoch.
[ { "created": "Tue, 18 Mar 2008 15:55:28 GMT", "version": "v1" }, { "created": "Fri, 13 Jun 2008 07:30:05 GMT", "version": "v2" } ]
2008-11-26
[ [ "Bauer", "Florian", "" ], [ "Demir", "Durmus A.", "" ] ]
We analyze non-minimally coupled scalar field theories in metric (second-order) and Palatini (first-order) formalisms in a comparative fashion. After contrasting them in a general setup, we specialize to inflation and find that the two formalisms differ in their predictions for various cosmological parameters. The main reason is that dependencies on the non-minimal coupling parameter are different in the two formalisms. For successful inflation, the Palatini approach prefers a much larger value for the non-minimal coupling parameter than the Metric approach. Unlike the Metric formalism, in Palatini, the inflaton stays well below the Planck scale whereby providing a natural inflationary epoch.
0811.0485
Carlos E. Yaguna
Carlos E. Yaguna
Inverse decays and the relic density of the sterile sneutrino
15 pages, 4 figures
Phys.Lett.B669:139-144,2008
10.1016/j.physletb.2008.09.048
IFT-UAM/CSIC-08-72
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider a weak scale supersymmetric seesaw model where the Higgsino is the next-to-lightest supersymmetric particle and the right-handed sneutrino is the dark matter candidate. It is shown that, in this model, inverse decays, which had been previously neglected, may suppress the sneutrino relic density by several orders of magnitude. After including such processes and numerically solving the appropriate Boltzmann equation, we study the dependence of the relic density on the mu parameter, the sneutrino mass, and the neutrino Yukawa coupling. We find that, even though much smaller than in earlier calculations, the sneutrino relic density is still larger than the observed dark matter density.
[ { "created": "Tue, 4 Nov 2008 11:58:27 GMT", "version": "v1" } ]
2011-01-25
[ [ "Yaguna", "Carlos E.", "" ] ]
We consider a weak scale supersymmetric seesaw model where the Higgsino is the next-to-lightest supersymmetric particle and the right-handed sneutrino is the dark matter candidate. It is shown that, in this model, inverse decays, which had been previously neglected, may suppress the sneutrino relic density by several orders of magnitude. After including such processes and numerically solving the appropriate Boltzmann equation, we study the dependence of the relic density on the mu parameter, the sneutrino mass, and the neutrino Yukawa coupling. We find that, even though much smaller than in earlier calculations, the sneutrino relic density is still larger than the observed dark matter density.
1001.2887
Alexander Smirnov
R.N. Lee, A.V. Smirnov, V.A. Smirnov
Analytic Results for Massless Three-Loop Form Factors
minor revisions, to appear in JHEP
JHEP 1004:020,2010
10.1007/JHEP04(2010)020
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We evaluate, exactly in d, the master integrals contributing to massless three-loop QCD form factors. The calculation is based on a combination of a method recently suggested by one of the authors (R.L.) with other techniques: sector decomposition implemented in FIESTA, the method of Mellin--Barnes representation, and the PSLQ algorithm. Using our results for the master integrals we obtain analytical expressions for two missing constants in the ep-expansion of the two most complicated master integrals and present the form factors in a completely analytic form.
[ { "created": "Sun, 17 Jan 2010 11:00:10 GMT", "version": "v1" }, { "created": "Fri, 12 Mar 2010 10:37:44 GMT", "version": "v2" } ]
2015-03-13
[ [ "Lee", "R. N.", "" ], [ "Smirnov", "A. V.", "" ], [ "Smirnov", "V. A.", "" ] ]
We evaluate, exactly in d, the master integrals contributing to massless three-loop QCD form factors. The calculation is based on a combination of a method recently suggested by one of the authors (R.L.) with other techniques: sector decomposition implemented in FIESTA, the method of Mellin--Barnes representation, and the PSLQ algorithm. Using our results for the master integrals we obtain analytical expressions for two missing constants in the ep-expansion of the two most complicated master integrals and present the form factors in a completely analytic form.
1009.1998
Sacha Davidson
Sacha Davidson and Sebastien Descotes-Genon
Minimal Flavour Violation for Leptoquarks
17 pages, 2 figures, minor changes and references added
JHEP 1011:073,2010
10.1007/JHEP11(2010)073
LPT-ORSAY/10-72
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Scalar leptoquarks, with baryon and lepton number conserving interactions, could have TeV scale masses, and be produced at colliders or contribute to a wide variety of rare decays. In pursuit of some insight as to the most sensitive search channels, We assume that the leptoquark-lepton-quark coupling can be constructed from the known mass matrices. We estimate the rates for selected rare processes in three cases: leptoquarks carrying lepton and quark flavour, leptoquarks with quark flavour only, and unflavoured leptoquarks. We find that leptoquark decay to top quarks is an interesting search channel.
[ { "created": "Fri, 10 Sep 2010 12:43:49 GMT", "version": "v1" }, { "created": "Wed, 29 Sep 2010 10:25:44 GMT", "version": "v2" } ]
2011-03-17
[ [ "Davidson", "Sacha", "" ], [ "Descotes-Genon", "Sebastien", "" ] ]
Scalar leptoquarks, with baryon and lepton number conserving interactions, could have TeV scale masses, and be produced at colliders or contribute to a wide variety of rare decays. In pursuit of some insight as to the most sensitive search channels, We assume that the leptoquark-lepton-quark coupling can be constructed from the known mass matrices. We estimate the rates for selected rare processes in three cases: leptoquarks carrying lepton and quark flavour, leptoquarks with quark flavour only, and unflavoured leptoquarks. We find that leptoquark decay to top quarks is an interesting search channel.
hep-ph/9406240
Frans Klinkhamer
F. R. Klinkhamer
Another Look at the Electroweak Vortex Solution
Latex, 6 pages, preprint NIKHEF-H / 94-19
null
null
null
hep-ph
null
We discuss the position in configuration space of the electroweak vortex solution. (Talk given at the NATO Advanced Research Workshop "Electroweak Physics and the Early Universe", Sintra, Portugal, March 1994)
[ { "created": "Tue, 7 Jun 1994 11:29:11 GMT", "version": "v1" } ]
2007-05-23
[ [ "Klinkhamer", "F. R.", "" ] ]
We discuss the position in configuration space of the electroweak vortex solution. (Talk given at the NATO Advanced Research Workshop "Electroweak Physics and the Early Universe", Sintra, Portugal, March 1994)
0710.1696
S. Descotes-Genon
S. Descotes-Genon (Orsay, LPT)
pi-pi and pi-K scatterings in three-flavour resummed chiral perturbation theory
Proceedings of the EPS-HEP 2007 Conference, Manchester (UK). 3 pages, 1 figure
J.Phys.Conf.Ser.110:052012,2008
10.1088/1742-6596/110/5/052012
LPT-ORSAY 07-78
hep-ph
null
The (light but not-so-light) strange quark may play a special role in the low-energy dynamics of QCD. The presence of strange quark pairs in the sea may have a significant impact of the pattern of chiral symmetry breaking : in particular large differences can occur between the chiral limits of two and three massless flavours (i.e., whether m_s is kept at its physical value or sent to zero). This may induce problems of convergence in three-flavour chiral expansions. To cope with such difficulties, we introduce a new framework, called Resummed Chiral Perturbation Theory. We exploit it to analyse pi-pi and pi-K scatterings and match them with dispersive results in a frequentist framework. Constraints on three-flavour chiral order parameters are derived.
[ { "created": "Tue, 9 Oct 2007 08:27:11 GMT", "version": "v1" } ]
2008-11-26
[ [ "Descotes-Genon", "S.", "", "Orsay, LPT" ] ]
The (light but not-so-light) strange quark may play a special role in the low-energy dynamics of QCD. The presence of strange quark pairs in the sea may have a significant impact of the pattern of chiral symmetry breaking : in particular large differences can occur between the chiral limits of two and three massless flavours (i.e., whether m_s is kept at its physical value or sent to zero). This may induce problems of convergence in three-flavour chiral expansions. To cope with such difficulties, we introduce a new framework, called Resummed Chiral Perturbation Theory. We exploit it to analyse pi-pi and pi-K scatterings and match them with dispersive results in a frequentist framework. Constraints on three-flavour chiral order parameters are derived.
2402.19221
Hua-Sheng Shao
Ajjath A H, Hua-Sheng Shao, and Lukas Simon
FKS subtraction for quarkonium production at NLO
53 pages, 2 figures, v2 (journal version)
JHEP 07 (2024) 050
10.1007/JHEP07(2024)050
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
We extend the local infrared-divergence subtraction formalism, originally proposed by Frixione, Kunszt and Signer (FKS), to calculate short-distance (differential) cross section for any inclusive process involving a quarkonium particle in non-relativistic QCD (NRQCD) factorisation at next-to-leading order (NLO) accuracy in the strong coupling constant $\alpha_s$. The new formulas are generally applicable to the production of an S- or P-wave quarkonium state in association with any number of elementary particles. The main new ingredients derived in this paper are the local and integrated soft counterterms for the colour-singlet and colour-octet P-wave bound states. It, therefore, paves the way to the automation of the NLO calculations for heavy quarkonium inclusive and associated production processes.
[ { "created": "Thu, 29 Feb 2024 14:53:46 GMT", "version": "v1" }, { "created": "Sat, 6 Jul 2024 10:55:37 GMT", "version": "v2" } ]
2024-07-09
[ [ "H", "Ajjath A", "" ], [ "Shao", "Hua-Sheng", "" ], [ "Simon", "Lukas", "" ] ]
We extend the local infrared-divergence subtraction formalism, originally proposed by Frixione, Kunszt and Signer (FKS), to calculate short-distance (differential) cross section for any inclusive process involving a quarkonium particle in non-relativistic QCD (NRQCD) factorisation at next-to-leading order (NLO) accuracy in the strong coupling constant $\alpha_s$. The new formulas are generally applicable to the production of an S- or P-wave quarkonium state in association with any number of elementary particles. The main new ingredients derived in this paper are the local and integrated soft counterterms for the colour-singlet and colour-octet P-wave bound states. It, therefore, paves the way to the automation of the NLO calculations for heavy quarkonium inclusive and associated production processes.
1609.03830
Samuel Wallon
R. Boussarie, B. Pire, L. Szymanowski, S. Wallon
Exclusive photoproduction of a $\gamma\,\rho$ pair with a large invariant mass
published version; 54 pages, 23 figures. The cross section for the exclusive photoproduction of a $\gamma\,\rho$ pair, in the case where the final $\rho$-meson is longitudinally polarized, has been corrected
null
10.1007/JHEP02(2017)054
CPHT-RR038.072016, LPT-Orsay-16-58
hep-ph hep-ex nucl-ex nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Exclusive photoproduction of a $\gamma\,\rho$ pair in the kinematics where the pair has a large invariant mass and the final nucleon has a small transverse momentum is described in the collinear factorization framework. The scattering amplitude is calculated at leading order in $\alpha_s$ and the differential cross sections for the process where the $\rho-$meson is either longitudinally or transversely polarized are estimated in the kinematics of the JLab 12-GeV experiments.
[ { "created": "Tue, 13 Sep 2016 13:48:21 GMT", "version": "v1" }, { "created": "Sun, 26 Feb 2017 09:42:22 GMT", "version": "v2" }, { "created": "Mon, 3 Sep 2018 15:40:38 GMT", "version": "v3" } ]
2018-09-05
[ [ "Boussarie", "R.", "" ], [ "Pire", "B.", "" ], [ "Szymanowski", "L.", "" ], [ "Wallon", "S.", "" ] ]
Exclusive photoproduction of a $\gamma\,\rho$ pair in the kinematics where the pair has a large invariant mass and the final nucleon has a small transverse momentum is described in the collinear factorization framework. The scattering amplitude is calculated at leading order in $\alpha_s$ and the differential cross sections for the process where the $\rho-$meson is either longitudinally or transversely polarized are estimated in the kinematics of the JLab 12-GeV experiments.
hep-ph/0610299
Urs M. Heller
Urs M. Heller
2+1 flavor simulations of QCD with improved staggered quarks
To appear in the proceedings of QNP06, IVth International Conference on Quarks and Nuclear Physics, Madrid, June 2006
Eur.Phys.J.A31:769-772,2007
10.1140/epja/i2006-10222-6
null
hep-ph hep-lat
null
The MILC collaboration has been performing realistic simulations of full QCD with 2+1 flavors of improved staggered quarks. Our simulations allow for controlled continuum and chiral extrapolations. I present results for the light pseudoscalar sector: masses and decay constants, quark masses and Gasser-Leutwyler low-energy constants. In addition I will present some results for heavy-light mesons, decay constants and semileptonic form factors, obtained in collaboration with the HPQCD and Fermilab lattice collaborations. Such calculations will help in the extraction of CKM matrix elements from experimental measurements.
[ { "created": "Mon, 23 Oct 2006 18:56:49 GMT", "version": "v1" } ]
2008-11-26
[ [ "Heller", "Urs M.", "" ] ]
The MILC collaboration has been performing realistic simulations of full QCD with 2+1 flavors of improved staggered quarks. Our simulations allow for controlled continuum and chiral extrapolations. I present results for the light pseudoscalar sector: masses and decay constants, quark masses and Gasser-Leutwyler low-energy constants. In addition I will present some results for heavy-light mesons, decay constants and semileptonic form factors, obtained in collaboration with the HPQCD and Fermilab lattice collaborations. Such calculations will help in the extraction of CKM matrix elements from experimental measurements.
hep-ph/0310150
Philip G. Ratcliffe
Philip G. Ratcliffe
QCD and Transverse-Spin Physics
Talk at the International Workshop on QCD: QCD@Work 2003 - Conversano (Italy) 14-18 June 2003 (eConf C030614). LaTeX2e; 8 pages; uses standard LaTeX macros (including psfrag), conference class file wqcd03.cls, and some personal macros (included). Figures are eps and feynmp generated (included in subfolders)
null
null
null
hep-ph
null
A pedagogical presentation of single-spin asymmetries and transversity is offered. Detailed discussion is given of various aspects of single-spin asymmetries in lepton-nucleon and in hadron-hadron scattering and of the role of perturbative QCD and evolution in the context of transversity.
[ { "created": "Mon, 13 Oct 2003 16:22:09 GMT", "version": "v1" } ]
2007-05-23
[ [ "Ratcliffe", "Philip G.", "" ] ]
A pedagogical presentation of single-spin asymmetries and transversity is offered. Detailed discussion is given of various aspects of single-spin asymmetries in lepton-nucleon and in hadron-hadron scattering and of the role of perturbative QCD and evolution in the context of transversity.
hep-ph/0005188
Francesco Terranova
Francesco Terranova
The impact of LEP 2 data on possible anomalous enhancements of Re e'/e
9 pages, 3 figures
Phys.Lett. B500 (2001) 113-117
10.1016/S0370-2693(01)00063-6
null
hep-ph
null
It has been shown in the past that the real part of the e'/e ratio is particularly sensitive to anomalous gauge couplings that modify the Standard Model Lagrangian. Due to the loose bounds on these couplings coming from low energy processes and to the poor sensitivity of hadron colliders to couplings such as $\Delta g_Z$, it has been argued that anomalous couplings could still produce an enhancement of Re e'/e bringing this observable closer to the experimental value obtained by KTeV, NA31 and NA48. The impact of the new measurements done at LEP2 in these years is discussed and new severe constraints to this hypothesis are determined.
[ { "created": "Thu, 18 May 2000 14:23:50 GMT", "version": "v1" } ]
2009-10-31
[ [ "Terranova", "Francesco", "" ] ]
It has been shown in the past that the real part of the e'/e ratio is particularly sensitive to anomalous gauge couplings that modify the Standard Model Lagrangian. Due to the loose bounds on these couplings coming from low energy processes and to the poor sensitivity of hadron colliders to couplings such as $\Delta g_Z$, it has been argued that anomalous couplings could still produce an enhancement of Re e'/e bringing this observable closer to the experimental value obtained by KTeV, NA31 and NA48. The impact of the new measurements done at LEP2 in these years is discussed and new severe constraints to this hypothesis are determined.
1206.5375
Patrick K. S. Vaudrevange
Mu-Chun Chen, Michael Ratz, Christian Staudt, Patrick K. S. Vaudrevange
The mu term and neutrino masses
24 pages
null
10.1016/j.nuclphysb.2012.08.018
UCI-TR-2012-08; TUM-HEP 845/12; DESY-12-108
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The well-known Giudice-Masiero mechanism explains the presence of a mu term of the order of the gravitino mass, but does not explain why the holomorphic mass term is absent in the superpotential. We discuss anomaly-free discrete symmetries which are both compatible with SU(5) unification of matter and the Giudice-Masiero mechanism, i.e. forbid the mu term in the superpotential while allowing the necessary Kaehler potential term. We find that these are Z_M^R symmetries with the following properties: (i) M is a multiple of four; (ii) the Higgs bilinear H_u H_d transforms trivially; (iii) the superspace coordinate theta has charge M/4 and, accordingly, the superpotential has charge M/2; (iv) dimension five proton decay operators are automatically absent. All Z_M^R symmetries are anomaly-free due to a non-trivial transformation of a Green-Schwarz axion, and, as a consequence, a holomorphic mu term appears at the non-perturbative level. There is a unique symmetry that is consistent with the Weinberg operator while there is a class of Z_M^R symmetries which explain suppressed Dirac neutrino masses.
[ { "created": "Sat, 23 Jun 2012 10:17:59 GMT", "version": "v1" }, { "created": "Tue, 3 Jul 2012 13:58:10 GMT", "version": "v2" } ]
2015-06-05
[ [ "Chen", "Mu-Chun", "" ], [ "Ratz", "Michael", "" ], [ "Staudt", "Christian", "" ], [ "Vaudrevange", "Patrick K. S.", "" ] ]
The well-known Giudice-Masiero mechanism explains the presence of a mu term of the order of the gravitino mass, but does not explain why the holomorphic mass term is absent in the superpotential. We discuss anomaly-free discrete symmetries which are both compatible with SU(5) unification of matter and the Giudice-Masiero mechanism, i.e. forbid the mu term in the superpotential while allowing the necessary Kaehler potential term. We find that these are Z_M^R symmetries with the following properties: (i) M is a multiple of four; (ii) the Higgs bilinear H_u H_d transforms trivially; (iii) the superspace coordinate theta has charge M/4 and, accordingly, the superpotential has charge M/2; (iv) dimension five proton decay operators are automatically absent. All Z_M^R symmetries are anomaly-free due to a non-trivial transformation of a Green-Schwarz axion, and, as a consequence, a holomorphic mu term appears at the non-perturbative level. There is a unique symmetry that is consistent with the Weinberg operator while there is a class of Z_M^R symmetries which explain suppressed Dirac neutrino masses.
2407.13639
Niyati Venkatesan
Kimmo Kainulainen, Niyati Venkatesan
Systematic moment expansion for electroweak baryogenesis
24 pages, 8 figures
null
null
null
hep-ph astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a systematic moment expansion for solving the semiclassical Boltzmann equations for electroweak baryogenesis. The expansion is developed in powers of adiabatic coordinate velocity, and it is used for computing the CP-violating seed asymmetry at the front of the phase transition wall, that sources the eventual baryon asymmetry of the universe (BAU). We implement the method in a benchmark model, with a CP-violating mass arising from a dimension-5 operator coupling the fermion to a singlet scalar field. We find that the higher moment calculations yield a BAU that can significantly differ from the commonly used two-moment approximation. We discuss in detail the underlying approximations in the moment method and propose a new truncation scheme for the expansion, that appears to give more numerically robust results than the previous schemes.
[ { "created": "Thu, 18 Jul 2024 16:17:29 GMT", "version": "v1" } ]
2024-07-19
[ [ "Kainulainen", "Kimmo", "" ], [ "Venkatesan", "Niyati", "" ] ]
We present a systematic moment expansion for solving the semiclassical Boltzmann equations for electroweak baryogenesis. The expansion is developed in powers of adiabatic coordinate velocity, and it is used for computing the CP-violating seed asymmetry at the front of the phase transition wall, that sources the eventual baryon asymmetry of the universe (BAU). We implement the method in a benchmark model, with a CP-violating mass arising from a dimension-5 operator coupling the fermion to a singlet scalar field. We find that the higher moment calculations yield a BAU that can significantly differ from the commonly used two-moment approximation. We discuss in detail the underlying approximations in the moment method and propose a new truncation scheme for the expansion, that appears to give more numerically robust results than the previous schemes.
2110.04271
Tae Hyun Jung
Tae Hyun Jung and Takemichi Okui
Primordial black holes from bubble collisions during a first-order phase transition
6 pages + 10 pages of supplemental material, 7 figures, v3: Major revision with significant improvement in presentation and analysis. Conclusion unchanged
null
null
KEK-TH-2350
hep-ph
http://creativecommons.org/licenses/by/4.0/
We find that collisions of near-horizon-sized bubbles with a thick fluid shell can produce primordial black holes (PBHs) during a first-order phase transition. We predict an approximately monochromatic PBH mass spectrum. In terms of a few parameters to be obtained from future numerical simulation, we estimate the PBH abundance in an Abelian Higgs benchmark model and show that it can be significant. In particular, the PBHs can constitute entire dark matter or even over-close the universe. Our result thus shows that models with a first-order phase transition can be constrained by over-abundant PBHs or null results of other PBH searches.
[ { "created": "Fri, 8 Oct 2021 17:33:54 GMT", "version": "v1" }, { "created": "Fri, 12 Nov 2021 22:38:57 GMT", "version": "v2" }, { "created": "Tue, 26 Dec 2023 17:52:15 GMT", "version": "v3" } ]
2023-12-27
[ [ "Jung", "Tae Hyun", "" ], [ "Okui", "Takemichi", "" ] ]
We find that collisions of near-horizon-sized bubbles with a thick fluid shell can produce primordial black holes (PBHs) during a first-order phase transition. We predict an approximately monochromatic PBH mass spectrum. In terms of a few parameters to be obtained from future numerical simulation, we estimate the PBH abundance in an Abelian Higgs benchmark model and show that it can be significant. In particular, the PBHs can constitute entire dark matter or even over-close the universe. Our result thus shows that models with a first-order phase transition can be constrained by over-abundant PBHs or null results of other PBH searches.
2005.08816
Xi-Jie Zhan
Xi-Jie Zhan, Jian-Xiong Wang
Prompt $J/\psi$ photoproduction within the non-relativistic QCD framework at the CEPC
null
null
10.1140/epjc/s10052-020-8276-0
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The prompt $J/\psi$ photoproduction within the non-relativistic QCD (NRQCD) framework at the future Circular Electron Positron Collider (CEPC) is studied, including the contributions from both direct and resolved photons. Employing different sets of long distance matrix elements, the total cross section is dominated by the color-octet channel. We present different kinematic distributions of $J/\psi$ production and the results show there will be about 50 $J/\psi$ events when the transverse momentum of $J/\psi$ is up to 20 GeV. It renders that the $J/\psi$ photoprodution at the CEPC is a well laboratory to test the NRQCD and further clarify the universality problem in NRQCD between electron positron collider and hadron collider.
[ { "created": "Mon, 18 May 2020 15:49:39 GMT", "version": "v1" } ]
2021-02-03
[ [ "Zhan", "Xi-Jie", "" ], [ "Wang", "Jian-Xiong", "" ] ]
The prompt $J/\psi$ photoproduction within the non-relativistic QCD (NRQCD) framework at the future Circular Electron Positron Collider (CEPC) is studied, including the contributions from both direct and resolved photons. Employing different sets of long distance matrix elements, the total cross section is dominated by the color-octet channel. We present different kinematic distributions of $J/\psi$ production and the results show there will be about 50 $J/\psi$ events when the transverse momentum of $J/\psi$ is up to 20 GeV. It renders that the $J/\psi$ photoprodution at the CEPC is a well laboratory to test the NRQCD and further clarify the universality problem in NRQCD between electron positron collider and hadron collider.
2204.07802
Yu Zhang
Yu Zhang, Mao Song, Ran Ding, Liangwen Chen
Neutrino dipole portal at electron colliders
11 pages, 3 figures, accepted for publication in Physics Letters B
null
10.1016/j.physletb.2022.137116
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
We propose to search for a heavy neutral lepton (HNL), that is also know as sterile neutrino, in electron colliders running with the center-of-mass energies at few GeV, including BESIII, Belle II, and the proposed Super Tau Charm Factory (STCF). We consider the HNL interacting with Standard Model neutrino and photon via a transition magnetic moment, the so-called dipole portal.We use the monophoton signature at electron colliders to probe the constraints on the active-sterile neutrino transition magnetic moments $d$ as the function of the HNL's mass $m_N$.It is found that BESIII, Belle II and STCF can probe the upper limits for $d$ down to 1.3 $\times 10^{-5}\ {\rm GeV}^{-1}$, 8 $\times 10^{-6}\ {\rm GeV}^{-1}$, and 1.3 $\times 10^{-6}\ {\rm GeV}^{-1}$ with $m_N$ around GeV scale, respectively, and have sensitivity to the previously unexplored parameter space for electron- ($d_e$) and tau-neutrino ($d_\tau$) dipole portal with $m_N$ from dozens to thounsands MeV. On $d_\mu$ for HNL mixing with the {muon}-neutrino, Belle II and STCF can also provide leading constraints.
[ { "created": "Sat, 16 Apr 2022 14:01:37 GMT", "version": "v1" } ]
2022-05-11
[ [ "Zhang", "Yu", "" ], [ "Song", "Mao", "" ], [ "Ding", "Ran", "" ], [ "Chen", "Liangwen", "" ] ]
We propose to search for a heavy neutral lepton (HNL), that is also know as sterile neutrino, in electron colliders running with the center-of-mass energies at few GeV, including BESIII, Belle II, and the proposed Super Tau Charm Factory (STCF). We consider the HNL interacting with Standard Model neutrino and photon via a transition magnetic moment, the so-called dipole portal.We use the monophoton signature at electron colliders to probe the constraints on the active-sterile neutrino transition magnetic moments $d$ as the function of the HNL's mass $m_N$.It is found that BESIII, Belle II and STCF can probe the upper limits for $d$ down to 1.3 $\times 10^{-5}\ {\rm GeV}^{-1}$, 8 $\times 10^{-6}\ {\rm GeV}^{-1}$, and 1.3 $\times 10^{-6}\ {\rm GeV}^{-1}$ with $m_N$ around GeV scale, respectively, and have sensitivity to the previously unexplored parameter space for electron- ($d_e$) and tau-neutrino ($d_\tau$) dipole portal with $m_N$ from dozens to thounsands MeV. On $d_\mu$ for HNL mixing with the {muon}-neutrino, Belle II and STCF can also provide leading constraints.
hep-ph/9602308
Oleg Kalashnikov
O.K.Kalashnikov
Magnetic Mass in Hot Scalar Electrodynamics
6 pages, Latex
null
null
BI-TH 96/09
hep-ph hep-th
null
Using the Slavnov-Taylor identities we prove that the so-called "magnetic mass" is exactly equal to zero within hot scalar electrodynamics. The same result is valid for hot QED and seems for any abelian theory but this is not the case for hot QCD where one expects that $\m\ne 0$.
[ { "created": "Wed, 14 Feb 1996 14:20:54 GMT", "version": "v1" } ]
2007-05-23
[ [ "Kalashnikov", "O. K.", "" ] ]
Using the Slavnov-Taylor identities we prove that the so-called "magnetic mass" is exactly equal to zero within hot scalar electrodynamics. The same result is valid for hot QED and seems for any abelian theory but this is not the case for hot QCD where one expects that $\m\ne 0$.
1809.04038
Andrzej Kup\'s\'c Dr
Elisabetta Perotti, G\"oran F\"aldt, Andrzej Kup\'s\'c, Stefan Leupold (Uppsala U.) and Jiao Jiao Song (Shandong U. and Beijing, Inst. High Energy Phys.)
Polarization observables in $e^+e^-$ annihilation to a baryon-antibaryon pair
16 pages;update: 1 figure, extended introduction and examples, results not changed
Phys. Rev. D 99, 056008 (2019)
10.1103/PhysRevD.99.056008
null
hep-ph hep-ex nucl-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Using the helicity formalism of Jacob and Wick we derive spin density matrices of baryon antibaryon pairs produced in $e^+e^-$ annihilation. We consider the production of pairs with spins $1/2+\overline{1/2}$, $1/2+\overline{3/2}$ (+c.c.) and $3/2+\overline{3/2}$. We provide modular expressions to include chains of weak hadronic two-body decays of the produced hyperons. The expressions are suitable for the analysis of high statistics data from $J/\psi$ and $\psi(2S)$ decays at $e^+e^-$ colliders, by fits to the fully differential angular distributions of the measured particles. We illustrate the method by examples, such as the inclusive measurement of the $e^+e^-\to\psi(2S)\to\Omega^-\bar\Omega^+$ process where one decay chain $\Omega^-\to\Lambda K^-$ followed by $\Lambda\to p\pi^-$ is considered. Finally we show that the inclusive angular distributions can be used to test spin assignment of the produced baryons.
[ { "created": "Tue, 11 Sep 2018 17:08:42 GMT", "version": "v1" }, { "created": "Thu, 28 Feb 2019 03:23:12 GMT", "version": "v2" } ]
2019-03-27
[ [ "Perotti", "Elisabetta", "", "Uppsala U." ], [ "Fäldt", "Göran", "", "Uppsala U." ], [ "Kupść", "Andrzej", "", "Uppsala U." ], [ "Leupold", "Stefan", "", "Uppsala U." ], [ "Song", "Jiao Jiao", "", "Shandong U. and Beijing, Inst. High Energy\n Phys." ] ]
Using the helicity formalism of Jacob and Wick we derive spin density matrices of baryon antibaryon pairs produced in $e^+e^-$ annihilation. We consider the production of pairs with spins $1/2+\overline{1/2}$, $1/2+\overline{3/2}$ (+c.c.) and $3/2+\overline{3/2}$. We provide modular expressions to include chains of weak hadronic two-body decays of the produced hyperons. The expressions are suitable for the analysis of high statistics data from $J/\psi$ and $\psi(2S)$ decays at $e^+e^-$ colliders, by fits to the fully differential angular distributions of the measured particles. We illustrate the method by examples, such as the inclusive measurement of the $e^+e^-\to\psi(2S)\to\Omega^-\bar\Omega^+$ process where one decay chain $\Omega^-\to\Lambda K^-$ followed by $\Lambda\to p\pi^-$ is considered. Finally we show that the inclusive angular distributions can be used to test spin assignment of the produced baryons.
hep-ph/9706452
Nestor Armesto
N. Armesto and A. Capella
Interpretations of $J/\psi$ suppression
12 pages, LaTeX, uses epsfig and ioplppt; review talk given by A. Capella at the International Symposium on Strangness in Quark Matter, Santorini (Greece), April 1997; Figs. 1 and 2 not available but can be found in Refs. 13 and 6 respectively
J.Phys.G23:1969-1977,1997
10.1088/0954-3899/23/12/022
LPTHE Orsay 97/31
hep-ph
null
We review the two main interpretations of $J/\psi$ suppression proposed in the literature. The phase transition (or deconfining) scenario assumes that below some critical value of the local energy density (or of some other geometrical quantity which depends both on the colliding systems and on the centrality of the collision), there is only nuclear absorption. Above this critical value the absorptive cross-section is taken to be infinite, i.e. no $J/\psi$ can survive in this hot region. In the hadronic scenario the $J/\psi$ dissociates due both to nuclear absorption and to its interactions with co-moving hadrons produced in the collision. No discontinuity exists in physical observables. We show that an equally good description of the present data is possible in either scenario.
[ { "created": "Mon, 23 Jun 1997 09:31:56 GMT", "version": "v1" } ]
2008-11-26
[ [ "Armesto", "N.", "" ], [ "Capella", "A.", "" ] ]
We review the two main interpretations of $J/\psi$ suppression proposed in the literature. The phase transition (or deconfining) scenario assumes that below some critical value of the local energy density (or of some other geometrical quantity which depends both on the colliding systems and on the centrality of the collision), there is only nuclear absorption. Above this critical value the absorptive cross-section is taken to be infinite, i.e. no $J/\psi$ can survive in this hot region. In the hadronic scenario the $J/\psi$ dissociates due both to nuclear absorption and to its interactions with co-moving hadrons produced in the collision. No discontinuity exists in physical observables. We show that an equally good description of the present data is possible in either scenario.
hep-ph/0210400
Stephen Godfrey
Stephen Godfrey (Carleton University, DESY)
Topics in Meson Spectroscopy
Invited talk given at 31st International Conference on High Energy Physics (ICHEP 2002), Amsterdam, The Netherlands, 24-31 Jul 2002
null
10.1016/S0920-5632(03)90640-2
DESY 02-170
hep-ph
null
In this mini-review I discuss three topics in meson spectroscopy. The production of heavy quarkonium states, S-wave scattering below 1 GeV, and exotic hybrid meson production. This is not intended to be a comprehensive review, just an overview of several topics of current interest.
[ { "created": "Tue, 29 Oct 2002 10:33:38 GMT", "version": "v1" } ]
2009-11-07
[ [ "Godfrey", "Stephen", "", "Carleton University, DESY" ] ]
In this mini-review I discuss three topics in meson spectroscopy. The production of heavy quarkonium states, S-wave scattering below 1 GeV, and exotic hybrid meson production. This is not intended to be a comprehensive review, just an overview of several topics of current interest.
1105.4984
Sanjib Kumar Agarwalla
Sanjib Kumar Agarwalla, J.M. Conrad, M.H. Shaevitz
Short-baseline Neutrino Oscillation Waves in Ultra-large Liquid Scintillator Detectors
24 pages, 8 figures, 9 tables
null
10.1007/JHEP12(2011)085
EURONU-WP6-11-32, IFIC/11-22
hep-ph hep-ex physics.ins-det
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Powerful new multi-kiloton liquid scintillator neutrino detectors, including NOvA and LENA, will come on-line within the next decade. When these are coupled with a modest-power decay-at-rest (DAR) neutrino source at short-baseline, these detectors can decisively address the recent ambiguous signals for neutrino oscillations at high Delta m^2. These detectors are > 50 m long, and so with a DAR beam, the characteristic oscillation wave will be apparent over the length of the detector, providing a powerful verification of the oscillation phenomena. LENA can simultaneously perform numubar to nuebar appearance and nue to nue disappearance searches with unprecedented sensitivity. NOvA is likely limited to nue disappearance given its present design, but also has excellent sensitivity in the high Delta m^2 region. For the appearance channel, LENA could provide a stringent test of the LSND and MiniBooNE signal regions at > 5 sigma with a reduced fiducial volume of 5 kt and a 10 kW neutrino source. In addition, the LENA and NOvA disappearance sensitivities in nue mode are complementary to the recent reactor anomaly indicating possible nuebar disappearance and would cover this possible oscillation signal at the 3 sigma level.
[ { "created": "Wed, 25 May 2011 10:07:33 GMT", "version": "v1" } ]
2015-05-28
[ [ "Agarwalla", "Sanjib Kumar", "" ], [ "Conrad", "J. M.", "" ], [ "Shaevitz", "M. H.", "" ] ]
Powerful new multi-kiloton liquid scintillator neutrino detectors, including NOvA and LENA, will come on-line within the next decade. When these are coupled with a modest-power decay-at-rest (DAR) neutrino source at short-baseline, these detectors can decisively address the recent ambiguous signals for neutrino oscillations at high Delta m^2. These detectors are > 50 m long, and so with a DAR beam, the characteristic oscillation wave will be apparent over the length of the detector, providing a powerful verification of the oscillation phenomena. LENA can simultaneously perform numubar to nuebar appearance and nue to nue disappearance searches with unprecedented sensitivity. NOvA is likely limited to nue disappearance given its present design, but also has excellent sensitivity in the high Delta m^2 region. For the appearance channel, LENA could provide a stringent test of the LSND and MiniBooNE signal regions at > 5 sigma with a reduced fiducial volume of 5 kt and a 10 kW neutrino source. In addition, the LENA and NOvA disappearance sensitivities in nue mode are complementary to the recent reactor anomaly indicating possible nuebar disappearance and would cover this possible oscillation signal at the 3 sigma level.
1707.09886
Yang Ma
Yang Ma, Xing-Gang Wu
Renormalization scheme dependence of high-Order perturbative QCD predictions
7 Page, 6 figures. Revised version to be published in Phys.Rev.D
Phys. Rev. D 97, 036024 (2018)
10.1103/PhysRevD.97.036024
PITT PACC-1708
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Conventionally, one adopts typical momentum flow of a physical observable as the renormalization scale for its perturbative QCD (pQCD) approximant. This simple treatment leads to renormalization scheme-and-scale ambiguities due to the renormalization scheme and scale dependence of the strong coupling and the perturbative coefficients do not exactly cancel at any fixed order. It is believed that those ambiguities will be softened by including more higher-order terms. In the paper, to show how the renormalization scheme dependence changes when more loop terms have been included, we discuss the sensitivity of pQCD prediction on the scheme parameters by using the scheme-dependent $\{\beta_{m \geq 2}\}$-terms. We adopt two four-loop examples, $e^+ e^- \to {\rm hadrons}$ and $\tau$ decays into hadrons, for detailed analysis. Our results show that under the conventional scale setting, by including more-and-more loop terms, the scheme dependence of the pQCD prediction cannot be reduced as efficiently as that of the scale dependence. Thus a proper scale-setting approach should be important to reduce the scheme dependence. We observe that the principle of minimum sensitivity could be such a scale-setting approach, which provides a practical way to achieve optimal scheme and scale by requiring the pQCD approximate be independent to the "unphysical" theoretical conventions.
[ { "created": "Mon, 31 Jul 2017 14:36:08 GMT", "version": "v1" }, { "created": "Tue, 2 Jan 2018 07:33:46 GMT", "version": "v2" }, { "created": "Fri, 2 Mar 2018 04:56:27 GMT", "version": "v3" } ]
2018-03-05
[ [ "Ma", "Yang", "" ], [ "Wu", "Xing-Gang", "" ] ]
Conventionally, one adopts typical momentum flow of a physical observable as the renormalization scale for its perturbative QCD (pQCD) approximant. This simple treatment leads to renormalization scheme-and-scale ambiguities due to the renormalization scheme and scale dependence of the strong coupling and the perturbative coefficients do not exactly cancel at any fixed order. It is believed that those ambiguities will be softened by including more higher-order terms. In the paper, to show how the renormalization scheme dependence changes when more loop terms have been included, we discuss the sensitivity of pQCD prediction on the scheme parameters by using the scheme-dependent $\{\beta_{m \geq 2}\}$-terms. We adopt two four-loop examples, $e^+ e^- \to {\rm hadrons}$ and $\tau$ decays into hadrons, for detailed analysis. Our results show that under the conventional scale setting, by including more-and-more loop terms, the scheme dependence of the pQCD prediction cannot be reduced as efficiently as that of the scale dependence. Thus a proper scale-setting approach should be important to reduce the scheme dependence. We observe that the principle of minimum sensitivity could be such a scale-setting approach, which provides a practical way to achieve optimal scheme and scale by requiring the pQCD approximate be independent to the "unphysical" theoretical conventions.
hep-ph/0407134
Szymanowski Lech dr
M. Diehl, B. Pire, L.Szymanowski
Exclusive Electroproduction of Pentaquarks
6 pages LATEX, 2 .eps figures, talk presented at DIS04, Strbske Pleso, Slovakia, April 2004
null
null
null
hep-ph
null
Exclusive electroproduction of a K or K^* meson on the nucleon can give a Theta^+ pentaquark in the final state. This reaction offers an opportunity to investigate the structure of pentaquark baryons at parton level. We discuss the generalized parton distributions for the N -> Theta^+ transition and give the leading order amplitude for electroproduction in the Bjorken regime.
[ { "created": "Mon, 12 Jul 2004 14:42:58 GMT", "version": "v1" } ]
2007-05-23
[ [ "Diehl", "M.", "" ], [ "Pire", "B.", "" ], [ "Szymanowski", "L.", "" ] ]
Exclusive electroproduction of a K or K^* meson on the nucleon can give a Theta^+ pentaquark in the final state. This reaction offers an opportunity to investigate the structure of pentaquark baryons at parton level. We discuss the generalized parton distributions for the N -> Theta^+ transition and give the leading order amplitude for electroproduction in the Bjorken regime.
1905.02564
Murat Koksal
M. K\"oksal, A. A. Billur, A. Guti\'errez-Rodr\'iguez and M. A. Hern\'andez-Ru\'iz
Sensitivity measuring expected on the electromagnetic anomalous couplings in the $t\bar t\gamma$ vertex at the FCC-he
28 pages, 10 figures and 7 tables. arXiv admin note: text overlap with arXiv:1812.08971
null
10.1142/S0217751X2050178X
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we consider the electroweak production cross-section of a single anti-top-quark, a neutrino and a photon via charged current through the $e^-p \to e^-\bar b \to \bar t \nu_e \gamma \to \bar t(\to W^- \to (qq', l^- \bar\nu_l)+b) \nu_e\gamma$ signal. Further, we derived the sensitivity expected to the magnetic dipole moment $(\hat a_V)$ and the electric dipole moment $(\hat a_A)$ of the top-quark at the Future Circular Collider Hadron Electron (FCC-he). We present our study for $\sqrt{s}=7.07, 10\hspace{0.8mm}TeV$, ${\cal L}=50, 100, 300, 500, 1000\hspace{0.8mm}fb^{-1}$, $\delta_{sys}=0, 3, 5\hspace{0.8mm}\%$ and $P_{e^-}=0\%, 80\%, -80\%$, respectively. We find that the sensitivity estimated on dipole moments of the top-quark is of the order of magnitude ${\cal O}(10^{-1})$ for both hadronic and leptonic decay modes of $W^-$: $\hat a_V=[-0.2308, 0.2204]$, $|\hat a_A|=0.2259$ at $95\%$ C.L. in the hadronic channel with unpolarized electron beam $P_{e^-}=0\%$. Our results with polarized electron beam for $P_{e^-}=80\%$ and $P_{e^-}=-80\%$ are $\hat a_V=[-0.3428, 0.3321]$, $|\hat a_A|=0.3371$ and $\hat a_V=[-0.2041, 0.1858]$, $|\hat a_A|=0.1939$ at $95\%$ C.L. in the hadronic channel. The corresponding results for the leptonic channel with $P_{e^-}=0\%, 80\% -80\%$ are $\hat a_V=[-0.3067, 0.2963]$, $|\hat a_A|=0.3019$, $\hat a_V=[-0.4563, 0.4456]$, $|\hat a_A|=0.4505$ and $\hat a_V=[-0.2695, 0.2512]$, $|\hat a_A|=0.2592$, respectively. The results for $\hat a_V$ and $\hat a_A$ in the leptonic channel are weaker by a factor of 0.75 than those corresponding to the hadronic channel. Given these prospective sensitivities we highlight that the FCC-he is potential top-quark factory that is particularly well suited to sensitivity study on its dipole moments and with cleaner environments.
[ { "created": "Sun, 5 May 2019 17:59:06 GMT", "version": "v1" } ]
2020-10-28
[ [ "Köksal", "M.", "" ], [ "Billur", "A. A.", "" ], [ "Gutiérrez-Rodríguez", "A.", "" ], [ "Hernández-Ruíz", "M. A.", "" ] ]
In this paper, we consider the electroweak production cross-section of a single anti-top-quark, a neutrino and a photon via charged current through the $e^-p \to e^-\bar b \to \bar t \nu_e \gamma \to \bar t(\to W^- \to (qq', l^- \bar\nu_l)+b) \nu_e\gamma$ signal. Further, we derived the sensitivity expected to the magnetic dipole moment $(\hat a_V)$ and the electric dipole moment $(\hat a_A)$ of the top-quark at the Future Circular Collider Hadron Electron (FCC-he). We present our study for $\sqrt{s}=7.07, 10\hspace{0.8mm}TeV$, ${\cal L}=50, 100, 300, 500, 1000\hspace{0.8mm}fb^{-1}$, $\delta_{sys}=0, 3, 5\hspace{0.8mm}\%$ and $P_{e^-}=0\%, 80\%, -80\%$, respectively. We find that the sensitivity estimated on dipole moments of the top-quark is of the order of magnitude ${\cal O}(10^{-1})$ for both hadronic and leptonic decay modes of $W^-$: $\hat a_V=[-0.2308, 0.2204]$, $|\hat a_A|=0.2259$ at $95\%$ C.L. in the hadronic channel with unpolarized electron beam $P_{e^-}=0\%$. Our results with polarized electron beam for $P_{e^-}=80\%$ and $P_{e^-}=-80\%$ are $\hat a_V=[-0.3428, 0.3321]$, $|\hat a_A|=0.3371$ and $\hat a_V=[-0.2041, 0.1858]$, $|\hat a_A|=0.1939$ at $95\%$ C.L. in the hadronic channel. The corresponding results for the leptonic channel with $P_{e^-}=0\%, 80\% -80\%$ are $\hat a_V=[-0.3067, 0.2963]$, $|\hat a_A|=0.3019$, $\hat a_V=[-0.4563, 0.4456]$, $|\hat a_A|=0.4505$ and $\hat a_V=[-0.2695, 0.2512]$, $|\hat a_A|=0.2592$, respectively. The results for $\hat a_V$ and $\hat a_A$ in the leptonic channel are weaker by a factor of 0.75 than those corresponding to the hadronic channel. Given these prospective sensitivities we highlight that the FCC-he is potential top-quark factory that is particularly well suited to sensitivity study on its dipole moments and with cleaner environments.
hep-ph/9608225
Masashi Hayakawa
M. Hayakawa ( KEK )
Remarks on the Hadronic Effect in Muon $g-2$: Low Energy Behavior of $V^0 $-$\pi^+$ Scattering
12 pages, REVTEX, 4 figures, Title and some other minor changes ( to appear in Phys. Rev. D )
Phys.Rev.D54:6586-6590,1996
10.1103/PhysRevD.54.R6586
KEK-TH-491, KEK Preprint 96-93
hep-ph
null
The behavior of the $V^0$-$\pi^+$ scattering amplitude (where $V^0 = \rho^0 , \omega$ , or $\phi$) in the low pion momentum limit is studied motivated by its relevance to the theory of muon $g - 2$. Current algebra analysis shows that its S-wave component must vanish in the chiral limit under general physical assumptions. We confirm this result with various low energy models of vector meson. Our result justifies the calculation of the charged pion loop part of the hadronic light-by-light scattering contribution to muon $ g-2 $ within the framework of hidden local symmetry model of low energy hadron dynamics.
[ { "created": "Mon, 5 Aug 1996 04:25:55 GMT", "version": "v1" }, { "created": "Sat, 12 Oct 1996 07:58:01 GMT", "version": "v2" }, { "created": "Mon, 14 Oct 1996 03:58:22 GMT", "version": "v3" } ]
2009-12-30
[ [ "Hayakawa", "M.", "", "KEK" ] ]
The behavior of the $V^0$-$\pi^+$ scattering amplitude (where $V^0 = \rho^0 , \omega$ , or $\phi$) in the low pion momentum limit is studied motivated by its relevance to the theory of muon $g - 2$. Current algebra analysis shows that its S-wave component must vanish in the chiral limit under general physical assumptions. We confirm this result with various low energy models of vector meson. Our result justifies the calculation of the charged pion loop part of the hadronic light-by-light scattering contribution to muon $ g-2 $ within the framework of hidden local symmetry model of low energy hadron dynamics.
hep-ph/9703252
Peter Kroll
Jan Bolz and Peter Kroll
Exclusive J/Psi and Psi'decays into baryon-antibaryon pairs
20 pages, 7 postscript figures, amstex
Eur.Phys.J.C2:545-556,1998
10.1007/s100520050160
WU B 97-2
hep-ph
null
Within a perturbative approach we investigate decays of charmonium states into baryon-antibaryon pairs. Using a recently proposed wave function for the nucleon and suitable generalizations of it to the hyperons and decouplet baryons, we obtain the decay widths for the baryon-antibaryon channels in reasonable agreement with data. An important difference to previous work is the use of the c-quark mass in the perturbative calculation instead of the charmonium mass. As a consequence of this feature our approach possesses, the J/Psi and the Psi' decay widths do not scale with a high power of the ratio of their masses.
[ { "created": "Thu, 6 Mar 1997 10:51:14 GMT", "version": "v1" } ]
2010-11-19
[ [ "Bolz", "Jan", "" ], [ "Kroll", "Peter", "" ] ]
Within a perturbative approach we investigate decays of charmonium states into baryon-antibaryon pairs. Using a recently proposed wave function for the nucleon and suitable generalizations of it to the hyperons and decouplet baryons, we obtain the decay widths for the baryon-antibaryon channels in reasonable agreement with data. An important difference to previous work is the use of the c-quark mass in the perturbative calculation instead of the charmonium mass. As a consequence of this feature our approach possesses, the J/Psi and the Psi' decay widths do not scale with a high power of the ratio of their masses.
hep-ph/0204247
Biswajoy Brahmachari
Biswajoy Brahmachari (Vidyasagar Evening College)
E_6 multiplets and unification in extra dimensions
Latex, eps figures
Acta Phys.Polon. B36 (2005) 1997-2004
null
SINP/TNP/02-14
hep-ph hep-th
null
We study the effect of all matter multiplets contained in {\bf 27} representation of $E_6$ GUT on gauge coupling unification in extra dimensions. Extra members of {\bf 27} multiplets of all three generations have their `zero modes' near $m_t$ such that they can be directly probed. From TeV scale onwards extra dimensions open up, theory becomes N=2 supersymmetric and gauge couplings unify or they do not, depending on how we distribute matter fields and gauge fields in bulk and brane. We find three such possible embedding which will lead to perfect gauge coupling unification below 100 TeV region for one extra dimension and lower than that if number of extra dimensions is larger.
[ { "created": "Mon, 22 Apr 2002 08:35:23 GMT", "version": "v1" }, { "created": "Mon, 6 Jun 2005 11:11:22 GMT", "version": "v2" } ]
2007-05-23
[ [ "Brahmachari", "Biswajoy", "", "Vidyasagar Evening College" ] ]
We study the effect of all matter multiplets contained in {\bf 27} representation of $E_6$ GUT on gauge coupling unification in extra dimensions. Extra members of {\bf 27} multiplets of all three generations have their `zero modes' near $m_t$ such that they can be directly probed. From TeV scale onwards extra dimensions open up, theory becomes N=2 supersymmetric and gauge couplings unify or they do not, depending on how we distribute matter fields and gauge fields in bulk and brane. We find three such possible embedding which will lead to perfect gauge coupling unification below 100 TeV region for one extra dimension and lower than that if number of extra dimensions is larger.
0707.0824
Sergey Afonin
S. S. Afonin
Properties of new unflavored mesons below 2.4 GeV
5 pages, to appear in Phys. Rev. C XX, 005200 (2007)
Phys.Rev.C76:015202,2007
10.1103/PhysRevC.76.015202
null
hep-ph
null
The global features of spectrum of highly excited light nonstrange mesons can be well understood within both chiral symmetry restoration scenario combined with the relation $M^2\sim J+n$ and within nonrelativistic description based on the relation $M^2\sim L+n$. The predictions of these two alternative classifications for missing states are different and only future experiments can distinguish between the two. We elaborate and compare systematically the predictions of both schemes, which may serve as a suggestion for future experiments devoted to the search for missing states.
[ { "created": "Thu, 5 Jul 2007 16:38:45 GMT", "version": "v1" } ]
2008-11-26
[ [ "Afonin", "S. S.", "" ] ]
The global features of spectrum of highly excited light nonstrange mesons can be well understood within both chiral symmetry restoration scenario combined with the relation $M^2\sim J+n$ and within nonrelativistic description based on the relation $M^2\sim L+n$. The predictions of these two alternative classifications for missing states are different and only future experiments can distinguish between the two. We elaborate and compare systematically the predictions of both schemes, which may serve as a suggestion for future experiments devoted to the search for missing states.
2103.15079
Xiaorui Wong
Xiaorui Wong and Yongsheng Huang
Dark photon production via $\gamma \gamma \rightarrow \gamma A'$
null
Eur. Phys. J. C 81, 442 (2021)
10.1140/epjc/s10052-021-09228-z
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The dark photon is a new gauge boson which arises from an extra U'(1) gauge symmetry. In this paper, a novel dark photon production mechanism based on MeV-scale $\gamma$-$\gamma$ collider is considered: $\gamma \gamma \rightarrow \gamma A'$. With the aid of PACKAGE-X, differential cross section of $\gamma \gamma \rightarrow \gamma A'$ is obtained, as a function of the kinetic mixing parameter $\varepsilon$ and dark photon mass $m_{A'}$. Taking the light-by-light scattering as background, the constraints on the dark photon parameter space for different time intervals in a MeV-scale $\gamma$-$\gamma$ collider are also given.
[ { "created": "Sun, 28 Mar 2021 08:14:50 GMT", "version": "v1" }, { "created": "Mon, 10 May 2021 15:39:48 GMT", "version": "v2" } ]
2021-05-25
[ [ "Wong", "Xiaorui", "" ], [ "Huang", "Yongsheng", "" ] ]
The dark photon is a new gauge boson which arises from an extra U'(1) gauge symmetry. In this paper, a novel dark photon production mechanism based on MeV-scale $\gamma$-$\gamma$ collider is considered: $\gamma \gamma \rightarrow \gamma A'$. With the aid of PACKAGE-X, differential cross section of $\gamma \gamma \rightarrow \gamma A'$ is obtained, as a function of the kinetic mixing parameter $\varepsilon$ and dark photon mass $m_{A'}$. Taking the light-by-light scattering as background, the constraints on the dark photon parameter space for different time intervals in a MeV-scale $\gamma$-$\gamma$ collider are also given.
1208.0987
Oleg Antipin A
Oleg Antipin, Matin Mojaza, Francesco Sannino
Jumping Out of the Light-Higgs Conformal Window
24 pages, 5 figures, minor corrections to match published version
null
10.1103/PhysRevD.87.096005
CP3-Origins-2012-21; DIAS-2012-22
hep-ph hep-lat hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate generic properties of the conformal phase transition in gauge theories featuring Higgs-like fundamental particles. These theories provide an excellent arena to properly investigate conformal dynamics and discover novel features. We show that the phase transition at the boundary of the Higgs conformal window is not smooth but a jumping one for the known perturbative examples. In addition the general conditions under which the transition is either jumping or smooth are provided. Jumping implies that the massive spectrum of the theory will jump at the phase transition. It, however, still allows for one of the states, the would be dilaton of the theory, to be lighter than the heaviest states in the broken phase. Finally we exhibit a calculable Higgs model in which we can, in perturbation theory, determine the Higgs conformal window, the spectrum in the conformally broken phase and demonstrate it to possess a jumping type conformal phase transition.
[ { "created": "Sun, 5 Aug 2012 07:48:47 GMT", "version": "v1" }, { "created": "Fri, 14 Jun 2013 11:46:29 GMT", "version": "v2" } ]
2013-06-17
[ [ "Antipin", "Oleg", "" ], [ "Mojaza", "Matin", "" ], [ "Sannino", "Francesco", "" ] ]
We investigate generic properties of the conformal phase transition in gauge theories featuring Higgs-like fundamental particles. These theories provide an excellent arena to properly investigate conformal dynamics and discover novel features. We show that the phase transition at the boundary of the Higgs conformal window is not smooth but a jumping one for the known perturbative examples. In addition the general conditions under which the transition is either jumping or smooth are provided. Jumping implies that the massive spectrum of the theory will jump at the phase transition. It, however, still allows for one of the states, the would be dilaton of the theory, to be lighter than the heaviest states in the broken phase. Finally we exhibit a calculable Higgs model in which we can, in perturbation theory, determine the Higgs conformal window, the spectrum in the conformally broken phase and demonstrate it to possess a jumping type conformal phase transition.
hep-ph/0207370
Gouranga C. Nayak
Fred Cooper (LANL), Chung-Wen Kao (Manchester), and Gouranga C. Nayak (LANL)
Non-Zero Magnetic Screening Mass in QED and QCD at One Loop Level in Non-Equilibrium
12 pages latex, 2 figures
null
null
null
hep-ph hep-lat hep-th nucl-th
null
Using the Schwinger-Keldysh closed time path integral formalism we show that the magnetic screening mass in QED and QCD at one loop level is non-zero as long as the single particle distribution function f(\vec{k}) is non-isotropic, {i.e.} it depends on the direction of the momentum. For isotropic distribution functions such as those corresponding to thermal equilibrium the magnetic screening mass at one loop level is found to be zero which is consistent with finite temperature field theory. The non-zero magnetic screening mass in non-isotropic non-equlibrium situations has fundamental importance in that it acts as a natural cut-off to remove infrared divergences in the magnetic sector. Thus it allows one to avoid infrared problems which previously made it difficult to use a transport theory approach using perturbative QCD or QED scattering kernels to study the thermalization of a QED or QCD plasma.
[ { "created": "Wed, 31 Jul 2002 18:17:01 GMT", "version": "v1" } ]
2007-05-23
[ [ "Cooper", "Fred", "", "LANL" ], [ "Kao", "Chung-Wen", "", "Manchester" ], [ "Nayak", "Gouranga C.", "", "LANL" ] ]
Using the Schwinger-Keldysh closed time path integral formalism we show that the magnetic screening mass in QED and QCD at one loop level is non-zero as long as the single particle distribution function f(\vec{k}) is non-isotropic, {i.e.} it depends on the direction of the momentum. For isotropic distribution functions such as those corresponding to thermal equilibrium the magnetic screening mass at one loop level is found to be zero which is consistent with finite temperature field theory. The non-zero magnetic screening mass in non-isotropic non-equlibrium situations has fundamental importance in that it acts as a natural cut-off to remove infrared divergences in the magnetic sector. Thus it allows one to avoid infrared problems which previously made it difficult to use a transport theory approach using perturbative QCD or QED scattering kernels to study the thermalization of a QED or QCD plasma.
1907.11846
Adam Coogan
Adam Coogan, Logan Morrison and Stefano Profumo
Hazma: A Python Toolkit for Studying Indirect Detection of Sub-GeV Dark Matter
Minor revisions; fixed typos in FSR spectra
null
10.1088/1475-7516/2020/01/056
null
hep-ph astro-ph.HE physics.comp-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
With several proposed MeV gamma-ray telescopes on the horizon, it is of paramount importance to perform accurate calculations of gamma-ray spectra expected from sub-GeV dark matter annihilation and decay. We present hazma, a python package for reliably computing these spectra, determining the resulting constraints from existing gamma-ray data, and prospects for upcoming telescopes. For high-level analyses, hazma comes with several built-in dark matter models where the interactions between dark matter and hadrons have been determined in detail using chiral perturbation theory. Additionally, hazma provides tools for computing spectra from individual final states with arbitrary numbers of light leptons and mesons, and for analyzing custom dark matter models. hazma can also produce electron and positron spectra from dark matter annihilation, enabling precise derivation of constraints from the cosmic microwave background.
[ { "created": "Sat, 27 Jul 2019 04:17:54 GMT", "version": "v1" }, { "created": "Mon, 16 Sep 2019 21:14:56 GMT", "version": "v2" }, { "created": "Fri, 6 Dec 2019 00:31:31 GMT", "version": "v3" } ]
2020-02-05
[ [ "Coogan", "Adam", "" ], [ "Morrison", "Logan", "" ], [ "Profumo", "Stefano", "" ] ]
With several proposed MeV gamma-ray telescopes on the horizon, it is of paramount importance to perform accurate calculations of gamma-ray spectra expected from sub-GeV dark matter annihilation and decay. We present hazma, a python package for reliably computing these spectra, determining the resulting constraints from existing gamma-ray data, and prospects for upcoming telescopes. For high-level analyses, hazma comes with several built-in dark matter models where the interactions between dark matter and hadrons have been determined in detail using chiral perturbation theory. Additionally, hazma provides tools for computing spectra from individual final states with arbitrary numbers of light leptons and mesons, and for analyzing custom dark matter models. hazma can also produce electron and positron spectra from dark matter annihilation, enabling precise derivation of constraints from the cosmic microwave background.
1901.04761
Seungwon Baek
Seungwon Baek
Scalar dark matter behind $b \to s \mu \mu$ anomaly
26 pages, 14 figures, matches the published version
JHEP 1905 (2019) 104
10.1007/JHEP05(2019)104
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We construct a scalar dark matter model with $U(1)_{L_\mu-L_\tau}$ symmetry in which the dark matter interacts with the quark flavours, allowing lepton non-universal $b \to s \ell \bar{\ell}$ decays. The model can solve $b \to s \mu \mu$ ($R_{K^{(*)}}$) anomaly and accommodate the relic abundance of dark matter simultaneously while satisfying the constraints from other low energy flavour experiments and direct detection experiments of dark matter. The new fields include vector-like heavy quarks $U$ and $D$, $U(1)_{L_\mu-L_\tau}$ breaking scalar $S$, as well as the dark matter candidate $X_I$ and its heavy partner $X_R$. To explain both $b \to s \mu \mu$ anomaly and the dark matter, {\it i)} large mass difference between $X_R$ and $X_I$ is required, {\it ii)} electroweak scale dark matter and heavy quarks are favoured, {\it iii)} not only electroweak scale but ${\cal O}(10)$ TeV dark gauge boson $Z'$ and $X_R$ are allowed.
[ { "created": "Tue, 15 Jan 2019 10:54:16 GMT", "version": "v1" }, { "created": "Tue, 12 Nov 2019 11:54:51 GMT", "version": "v2" } ]
2019-11-13
[ [ "Baek", "Seungwon", "" ] ]
We construct a scalar dark matter model with $U(1)_{L_\mu-L_\tau}$ symmetry in which the dark matter interacts with the quark flavours, allowing lepton non-universal $b \to s \ell \bar{\ell}$ decays. The model can solve $b \to s \mu \mu$ ($R_{K^{(*)}}$) anomaly and accommodate the relic abundance of dark matter simultaneously while satisfying the constraints from other low energy flavour experiments and direct detection experiments of dark matter. The new fields include vector-like heavy quarks $U$ and $D$, $U(1)_{L_\mu-L_\tau}$ breaking scalar $S$, as well as the dark matter candidate $X_I$ and its heavy partner $X_R$. To explain both $b \to s \mu \mu$ anomaly and the dark matter, {\it i)} large mass difference between $X_R$ and $X_I$ is required, {\it ii)} electroweak scale dark matter and heavy quarks are favoured, {\it iii)} not only electroweak scale but ${\cal O}(10)$ TeV dark gauge boson $Z'$ and $X_R$ are allowed.
hep-ph/9909526
Athenasios Dedes
A. Dedes and S. Moretti (Rutherford Appleton Lab.)
Higgs boson production in association with squark pairs in the MSSM at the LHC
4 pages, Talk given by A. Dedes at the XIth Recontres de Blois, ``Frontiers of Matter'', June 27-July 3, 1999, France
null
null
RAL-TR-1999-067
hep-ph
null
We study neutral and charged Higgs boson production in association with stop and sbottom squarks at the Large Hadron Collider (LHC), within the so-called M-SUGRA scenario, i.e., the Supergravity (SUGRA) inspired Minimal Supersymmetric Standard Model (MSSM). For low values of \tan\beta only the cases \tilde{t}_1\tilde{t}_1^* H, \tilde{t}_1\tilde{t}_1^* h and \tilde{t}_1\tilde{t}_2^* h give detectable rates while for \tan\beta greater than 30 a variety of signals involving all Higgs bosons can be accessed, at high collider luminosity. The dependence of these reactions on the M-SUGRA parameters might further allow one to pin down the actual structure of the underlying Supersymmetric (SUSY) model.
[ { "created": "Tue, 28 Sep 1999 10:07:48 GMT", "version": "v1" } ]
2007-05-23
[ [ "Dedes", "A.", "", "Rutherford Appleton Lab." ], [ "Moretti", "S.", "", "Rutherford Appleton Lab." ] ]
We study neutral and charged Higgs boson production in association with stop and sbottom squarks at the Large Hadron Collider (LHC), within the so-called M-SUGRA scenario, i.e., the Supergravity (SUGRA) inspired Minimal Supersymmetric Standard Model (MSSM). For low values of \tan\beta only the cases \tilde{t}_1\tilde{t}_1^* H, \tilde{t}_1\tilde{t}_1^* h and \tilde{t}_1\tilde{t}_2^* h give detectable rates while for \tan\beta greater than 30 a variety of signals involving all Higgs bosons can be accessed, at high collider luminosity. The dependence of these reactions on the M-SUGRA parameters might further allow one to pin down the actual structure of the underlying Supersymmetric (SUSY) model.
1610.10081
Rome Samanta
Rome Samanta, Mainak Chakraborty, Probir Roy and Ambar Ghosal
Baryon asymmetry via leptogenesis in a neutrino mass model with complex scaling
17 pages, 19 figures, effect of $N_2$ leptogenesis is added in Sec. 6, version to appear in JCAP
null
10.1088/1475-7516/2017/03/025
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Baryogenesis via leptogenesis is investigated in a specific model of light neutrino masses and mixing angles. The latter was proposed on the basis of an assumed complex-extended scaling property of the neutrino Majorana mass matrix $M_\nu$, derived with a type-1 seesaw from a Dirac mass matrix $m_D$ and a heavy singlet neutrino Majorana mass matrix $M_R$. One of its important features, highlighted here, is that there is a common source of the origin of a nonzero $\theta_{13}$ and the CP violating lepton asymmetry through the imaginary part of $m_D$. The model predicted CP violation to be maximal for the Dirac type and vanishing for the Majorana type. We assume strongly hierarchical mass eigenvalues for $M_R$. The leptonic CP asymmetry parameter $\varepsilon^\alpha_{1}\hspace{1mm}$ with lepton flavor $\alpha$, originating from the decays of the lightest of the heavy neutrinos $N_1$ (of mass $M_1$) at a temperature $T\sim M_1$, is what matters here with $\varepsilon^\alpha_{2,3}$, originating from the decays of $N_{2,3}$, being washed out. The light leptonic and heavy neutrino number densities (normalized to the entropy density) are evolved via Boltzmann equations down to electroweak temperatures to yield a baryon asymmetry through sphaleronic transitions. The effect of flavored vs. unflavored leptogenesis in the three mass regimes (1) $M_1<10^{9}$ GeV, (2) $10^9$ GeV $<M_1<$ $10^{12}$ GeV and (3) $M_1>10^{12}$ GeV are numerically worked out for both a normal and an inverted mass ordering of the light neutrinos. Corresponding results on the baryon asymmetry of the universe are obtained, displayed and discussed.
[ { "created": "Mon, 31 Oct 2016 19:36:24 GMT", "version": "v1" }, { "created": "Mon, 6 Mar 2017 11:23:07 GMT", "version": "v2" } ]
2017-03-22
[ [ "Samanta", "Rome", "" ], [ "Chakraborty", "Mainak", "" ], [ "Roy", "Probir", "" ], [ "Ghosal", "Ambar", "" ] ]
Baryogenesis via leptogenesis is investigated in a specific model of light neutrino masses and mixing angles. The latter was proposed on the basis of an assumed complex-extended scaling property of the neutrino Majorana mass matrix $M_\nu$, derived with a type-1 seesaw from a Dirac mass matrix $m_D$ and a heavy singlet neutrino Majorana mass matrix $M_R$. One of its important features, highlighted here, is that there is a common source of the origin of a nonzero $\theta_{13}$ and the CP violating lepton asymmetry through the imaginary part of $m_D$. The model predicted CP violation to be maximal for the Dirac type and vanishing for the Majorana type. We assume strongly hierarchical mass eigenvalues for $M_R$. The leptonic CP asymmetry parameter $\varepsilon^\alpha_{1}\hspace{1mm}$ with lepton flavor $\alpha$, originating from the decays of the lightest of the heavy neutrinos $N_1$ (of mass $M_1$) at a temperature $T\sim M_1$, is what matters here with $\varepsilon^\alpha_{2,3}$, originating from the decays of $N_{2,3}$, being washed out. The light leptonic and heavy neutrino number densities (normalized to the entropy density) are evolved via Boltzmann equations down to electroweak temperatures to yield a baryon asymmetry through sphaleronic transitions. The effect of flavored vs. unflavored leptogenesis in the three mass regimes (1) $M_1<10^{9}$ GeV, (2) $10^9$ GeV $<M_1<$ $10^{12}$ GeV and (3) $M_1>10^{12}$ GeV are numerically worked out for both a normal and an inverted mass ordering of the light neutrinos. Corresponding results on the baryon asymmetry of the universe are obtained, displayed and discussed.
2308.00027
Jona Ackerschott
Jona Ackerschott, Rahool Kumar Barman, Dorival Gon\c{c}alves, Theo Heimel, Tilman Plehn
Returning CP-Observables to The Frames They Belong
25 pages, 7 figures
SciPost Phys. 17, 001 (2024)
10.21468/SciPostPhys.17.1.001
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
Optimal kinematic observables are often defined in specific frames and then approximated at the reconstruction level. We show how multi-dimensional unfolding methods allow us to reconstruct these observables in their proper rest frame and in a probabilistically faithful way. We illustrate our approach with a measurement of a CP-phase in the top Yukawa coupling. Our method makes use of key advantages of generative unfolding, but as a constructed observable it fits into standard LHC analysis frameworks.
[ { "created": "Mon, 31 Jul 2023 18:00:01 GMT", "version": "v1" } ]
2024-07-03
[ [ "Ackerschott", "Jona", "" ], [ "Barman", "Rahool Kumar", "" ], [ "Gonçalves", "Dorival", "" ], [ "Heimel", "Theo", "" ], [ "Plehn", "Tilman", "" ] ]
Optimal kinematic observables are often defined in specific frames and then approximated at the reconstruction level. We show how multi-dimensional unfolding methods allow us to reconstruct these observables in their proper rest frame and in a probabilistically faithful way. We illustrate our approach with a measurement of a CP-phase in the top Yukawa coupling. Our method makes use of key advantages of generative unfolding, but as a constructed observable it fits into standard LHC analysis frameworks.
2403.02916
Francesco Rosini
Francesco Rosini, Simone Pacetti, Olga Shekhovtsova, Egle Tomasi-Gustafsson
Microscopic parametrization of the near threshold oscillations of the nucleon time-like effective electromagnetic form factors
8 pages, 4 figures
Eur. Phys. J. A 60, 144 (2024)
10.1140/epja/s10050-024-01365-9
null
hep-ph hep-ex nucl-th
http://creativecommons.org/licenses/by/4.0/
We present an analysis of the recent near threshold BESIII data for the nucleon time-like effective form factors. The damped oscillation emerging from the subtraction of the dipole formula is treated in non-perturbative-QCD, making use of the light cone distribution amplitudes expansion. Non-perturbative effects are accounted for by considering Q2-dependent coefficients in such expansions, whose free parameters are determined by fitting to the proton and neutron data. Possible implications and future analysis have been discussed.
[ { "created": "Tue, 5 Mar 2024 12:34:29 GMT", "version": "v1" }, { "created": "Tue, 18 Jun 2024 14:53:08 GMT", "version": "v2" } ]
2024-07-12
[ [ "Rosini", "Francesco", "" ], [ "Pacetti", "Simone", "" ], [ "Shekhovtsova", "Olga", "" ], [ "Tomasi-Gustafsson", "Egle", "" ] ]
We present an analysis of the recent near threshold BESIII data for the nucleon time-like effective form factors. The damped oscillation emerging from the subtraction of the dipole formula is treated in non-perturbative-QCD, making use of the light cone distribution amplitudes expansion. Non-perturbative effects are accounted for by considering Q2-dependent coefficients in such expansions, whose free parameters are determined by fitting to the proton and neutron data. Possible implications and future analysis have been discussed.
1006.5950
Alexander Isayev
A. A. Isayev
Phenomenology of Heavy Flavors in Ultrarelativistic Heavy-Ion Collisions
Based on the lecture given at the Xth International School-Seminar "The Actual Problems of Microworld Physics", Gomel, Belarus, July 15 - 26, 2009
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Some recent experimental results obtained in collisions of heavy nuclei ($\sqrt{s}=200$ GeV) at BNL Relativistic Heavy-Ion Collider (RHIC) are discussed. The probes of dense matter created in heavy-ion collision by quarkonia, $D$ and $B$ mesons containing heavy charm and beauty quarks are considered. The centrality, rapidity and transverse momentum dependences of the nuclear modification factor and elliptic flow coefficient are presented and their possible theoretical interpretation is provided.
[ { "created": "Wed, 30 Jun 2010 18:54:44 GMT", "version": "v1" } ]
2010-07-01
[ [ "Isayev", "A. A.", "" ] ]
Some recent experimental results obtained in collisions of heavy nuclei ($\sqrt{s}=200$ GeV) at BNL Relativistic Heavy-Ion Collider (RHIC) are discussed. The probes of dense matter created in heavy-ion collision by quarkonia, $D$ and $B$ mesons containing heavy charm and beauty quarks are considered. The centrality, rapidity and transverse momentum dependences of the nuclear modification factor and elliptic flow coefficient are presented and their possible theoretical interpretation is provided.
1903.10844
Christian Fischer
Gernot Eichmann, Christian S. Fischer, Esther Weil, Richard Williams
Single pseudoscalar meson pole and pion box contributions to the anomalous magnetic moment of the muon
11 pages, 9 figures; v2: minor changes, diagram added, improved value for pion-box; version published in PLB
null
10.1016/j.physletb.2019.134855
null
hep-ph hep-lat
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present results for single pseudoscalar meson pole contributions and pion box contributions to the hadronic light-by-light (LBL) correction of the muon's anomalous magnetic moment. We follow the recently developed dispersive approach to LBL, where these contributions are evaluated with intermediate mesons on-shell. However, the space-like electromagnetic and transition form factors are not determined from analytic continuation of time-like data, but directly calculated within the functional approach to QCD using Dyson-Schwinger and Bethe-Salpeter equations. This strategy allows for a systematic comparison with a strictly dispersive treatment and also with recent results from lattice QCD. Within error bars, we obtain excellent agreement for the pion electromagnetic and transition form factor and the resulting contributions to LBL. In addition, we present results for the $\eta$ and $\eta'$ pole contributions and discuss the dynamical effects in the $\eta-\eta'$ mixing due to the strange quarks. Our result for the total pseudoscalar pole contributions is $a_\mu^{\text{PS-pole}} = 91.6 \,(1.9) \times 10^{-11}$ and for the pion-box contribution we obtain $a_\mu^{\pi-\text{box}} = -16.3 \,(2)(4) \times 10^{-11}$.
[ { "created": "Tue, 26 Mar 2019 12:58:06 GMT", "version": "v1" }, { "created": "Fri, 11 Oct 2019 09:03:30 GMT", "version": "v2" } ]
2019-10-14
[ [ "Eichmann", "Gernot", "" ], [ "Fischer", "Christian S.", "" ], [ "Weil", "Esther", "" ], [ "Williams", "Richard", "" ] ]
We present results for single pseudoscalar meson pole contributions and pion box contributions to the hadronic light-by-light (LBL) correction of the muon's anomalous magnetic moment. We follow the recently developed dispersive approach to LBL, where these contributions are evaluated with intermediate mesons on-shell. However, the space-like electromagnetic and transition form factors are not determined from analytic continuation of time-like data, but directly calculated within the functional approach to QCD using Dyson-Schwinger and Bethe-Salpeter equations. This strategy allows for a systematic comparison with a strictly dispersive treatment and also with recent results from lattice QCD. Within error bars, we obtain excellent agreement for the pion electromagnetic and transition form factor and the resulting contributions to LBL. In addition, we present results for the $\eta$ and $\eta'$ pole contributions and discuss the dynamical effects in the $\eta-\eta'$ mixing due to the strange quarks. Our result for the total pseudoscalar pole contributions is $a_\mu^{\text{PS-pole}} = 91.6 \,(1.9) \times 10^{-11}$ and for the pion-box contribution we obtain $a_\mu^{\pi-\text{box}} = -16.3 \,(2)(4) \times 10^{-11}$.
2105.10279
Hyun-Chul Kim
June-Young Kim and Hyun-Chul Kim
Energy-momentum tensor of the nucleon on the light front: Abel tomography case
10 pages and 5 figures
null
10.1103/PhysRevD.104.074019
INHA-NTG-04/2021
hep-ph hep-ex hep-lat
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate the two-dimensional energy-momentum-tensor (EMT) distributions of the nucleon on the light front, using the Abel transforms of the three-dimensional EMT ones. We explicitly show that the main features of all EMT distributions are kept intact in the course of the Abel transform. We also examine the equivalence between the global and local conditions for the nucleon stability in the three-dimensional Breit frame and in the two-dimensional transverse plane on the light front. We also discuss the two-dimensional force fields inside a nucleon on the light front.
[ { "created": "Fri, 21 May 2021 11:05:39 GMT", "version": "v1" } ]
2021-10-27
[ [ "Kim", "June-Young", "" ], [ "Kim", "Hyun-Chul", "" ] ]
We investigate the two-dimensional energy-momentum-tensor (EMT) distributions of the nucleon on the light front, using the Abel transforms of the three-dimensional EMT ones. We explicitly show that the main features of all EMT distributions are kept intact in the course of the Abel transform. We also examine the equivalence between the global and local conditions for the nucleon stability in the three-dimensional Breit frame and in the two-dimensional transverse plane on the light front. We also discuss the two-dimensional force fields inside a nucleon on the light front.
2003.02988
Hong-Shi Zong
Zu-Qing Wu, Chao-Shi, Jia-Lun Ping, Hong-Shi Zong
The contributions of the vector-channel at finite isospin chemical potential with the self-consistent mean field approximation
6 figures, 10 pages
Phys. Rev. D 101, 074008 (2020)
10.1103/PhysRevD.101.074008
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The self-consistent mean field approximation of two-flavor NJL model, which introduces a free parameter $\alpha$ ($\alpha$ reflects the weight of different interaction channels), is employed to investigate the contributions of the vector-channel at finite isospin chemical potential $\mu_I$ and zero baryon chemical potential $\mu_B$ and zero temperature $T$. The calculations show that the consideration of the vector-channel contributions leads to lower value of pion condensate in superfluid phase, compared with the standard Lagrangian of NJL model ($\alpha=0$). In superfluid phase, we also obtain lower isospin number density, and the discrepancy is getting larger with the increase of isospin potential. Compared with the recent results from Lattice QCD, the isospin density and energy density we obtained with $\alpha=0.5$ agree with the data of lattice well. In the phase diagram in the $T-\mu_I$ plane for $\mu_B=0$, we can see that the difference of the critical temperatures of phase transition between the results with $\alpha=0$ and $\alpha=0.5$ is up to $3\%-5\%$ for a fixed isospin potential. All of these indicate that the vector channels play an important role in isospin medium.
[ { "created": "Fri, 6 Mar 2020 01:28:26 GMT", "version": "v1" } ]
2020-04-15
[ [ "Wu", "Zu-Qing", "" ], [ "Chao-Shi", "", "" ], [ "Ping", "Jia-Lun", "" ], [ "Zong", "Hong-Shi", "" ] ]
The self-consistent mean field approximation of two-flavor NJL model, which introduces a free parameter $\alpha$ ($\alpha$ reflects the weight of different interaction channels), is employed to investigate the contributions of the vector-channel at finite isospin chemical potential $\mu_I$ and zero baryon chemical potential $\mu_B$ and zero temperature $T$. The calculations show that the consideration of the vector-channel contributions leads to lower value of pion condensate in superfluid phase, compared with the standard Lagrangian of NJL model ($\alpha=0$). In superfluid phase, we also obtain lower isospin number density, and the discrepancy is getting larger with the increase of isospin potential. Compared with the recent results from Lattice QCD, the isospin density and energy density we obtained with $\alpha=0.5$ agree with the data of lattice well. In the phase diagram in the $T-\mu_I$ plane for $\mu_B=0$, we can see that the difference of the critical temperatures of phase transition between the results with $\alpha=0$ and $\alpha=0.5$ is up to $3\%-5\%$ for a fixed isospin potential. All of these indicate that the vector channels play an important role in isospin medium.
1701.04597
Yueling Yang
Junfeng Sun, Yueling Yang, Qingxia Li, Haiyan Li, Qin Chang, Jinshu Huang
The ${\Upsilon}(nS)$ ${\to}$ $B_{c}D_{s}$, $B_{c}D_{d}$ decays with perturbative QCD approach
18 pages, 2 figures. arXiv admin note: text overlap with arXiv:1604.07040
Physics Letters B 752, 322-328 (2016)
10.1016/j.physletb.2015.11.053
null
hep-ph hep-ex
http://creativecommons.org/licenses/by/4.0/
The ${\Upsilon}(nS)$ ${\to}$ $B_{c}D_{s}$, $B_{c}D_{d}$ weak decays are studied with the pQCD approach firstly. It is found that branching ratios ${\cal B}r({\Upsilon}(nS){\to}B_{c}D_{s})$ ${\sim}$ ${\cal O}(10^{-10})$ and ${\cal B}r({\Upsilon}(nS){\to}B_{c}D_{d})$ ${\sim}$ ${\cal O}(10^{-11})$, which might be measurable in the future experiments.
[ { "created": "Tue, 17 Jan 2017 09:50:49 GMT", "version": "v1" } ]
2017-02-12
[ [ "Sun", "Junfeng", "" ], [ "Yang", "Yueling", "" ], [ "Li", "Qingxia", "" ], [ "Li", "Haiyan", "" ], [ "Chang", "Qin", "" ], [ "Huang", "Jinshu", "" ] ]
The ${\Upsilon}(nS)$ ${\to}$ $B_{c}D_{s}$, $B_{c}D_{d}$ weak decays are studied with the pQCD approach firstly. It is found that branching ratios ${\cal B}r({\Upsilon}(nS){\to}B_{c}D_{s})$ ${\sim}$ ${\cal O}(10^{-10})$ and ${\cal B}r({\Upsilon}(nS){\to}B_{c}D_{d})$ ${\sim}$ ${\cal O}(10^{-11})$, which might be measurable in the future experiments.
hep-ph/9807453
Bugra Borasoy
B. Borasoy
Sigma-terms in heavy baryon chiral perturbation theory revisited
17 pages
Eur.Phys.J.C8:121-130,1999
10.1007/s100520050451
null
hep-ph
null
The $\sigma$-terms are calculated at next-to-leading order in heavy baryon chiral perturbation theory by employing a cutoff regularization. The results do not depend on the cutoff value to the order we are working . The baryon masses and $\sigma_{\pi N}(0)$ are used to perform a least-squares fit to the three appearing low-energy constants and predictions for the two $KN$ $\sigma$-terms and the strange contribution to the nucleon mass are made. The lack of convergence in the chiral expansions of these quantities when regularized dimensionally is overcome in the cutoff scheme. The $\sigma$-term shifts to the pertinent Cheng-Dashen points are calculated. We also include the spin-3/2 decuplet in the effective theory.
[ { "created": "Tue, 21 Jul 1998 18:31:29 GMT", "version": "v1" } ]
2011-09-13
[ [ "Borasoy", "B.", "" ] ]
The $\sigma$-terms are calculated at next-to-leading order in heavy baryon chiral perturbation theory by employing a cutoff regularization. The results do not depend on the cutoff value to the order we are working . The baryon masses and $\sigma_{\pi N}(0)$ are used to perform a least-squares fit to the three appearing low-energy constants and predictions for the two $KN$ $\sigma$-terms and the strange contribution to the nucleon mass are made. The lack of convergence in the chiral expansions of these quantities when regularized dimensionally is overcome in the cutoff scheme. The $\sigma$-term shifts to the pertinent Cheng-Dashen points are calculated. We also include the spin-3/2 decuplet in the effective theory.
hep-ph/9702334
Tao Han
V. Barger, M.S. Berger, J.F. Gunion and T. Han
Precision W-boson and top-quark mass determinations at a muon collider
27 pages, 11 figures, postscript file available via anonymous ftp://ucdhep.ucdavis.edu/han/mumu/mwmt.ps
Phys.Rev.D56:1714-1722,1997
10.1103/PhysRevD.56.1714
MADPH-96-963, IUHET-346, UCD-97-01
hep-ph hep-ex
null
Precise determinations of the masses of the $W$ boson and of the top quark could stringently test the radiative structure of the Standard Model (SM) or provide evidence for new physics. We analyze the excellent prospects at a muon collider for measuring $M_W$ and $m_t$ in the $W^+W^-$ and $t\bar t$ threshold regions. With an integrated luminosity of 10 (100) fb$^{-1}$, the $W$-boson mass could be measured to a precision of 20 (6) MeV, and the top-quark mass to a precision of 200 (70) MeV, provided that theoretical and experimental systematics are understood. A measurement of $\Delta m_t=200$ MeV for fixed $M_W$ would constrain a 100 GeV SM Higgs mass within about $\pm 2$ GeV, while $\Delta M_W=6$ MeV for fixed $m_t$ would constrain $m_h$ to about $\pm 10$ GeV.
[ { "created": "Fri, 14 Feb 1997 05:31:39 GMT", "version": "v1" } ]
2009-09-15
[ [ "Barger", "V.", "" ], [ "Berger", "M. S.", "" ], [ "Gunion", "J. F.", "" ], [ "Han", "T.", "" ] ]
Precise determinations of the masses of the $W$ boson and of the top quark could stringently test the radiative structure of the Standard Model (SM) or provide evidence for new physics. We analyze the excellent prospects at a muon collider for measuring $M_W$ and $m_t$ in the $W^+W^-$ and $t\bar t$ threshold regions. With an integrated luminosity of 10 (100) fb$^{-1}$, the $W$-boson mass could be measured to a precision of 20 (6) MeV, and the top-quark mass to a precision of 200 (70) MeV, provided that theoretical and experimental systematics are understood. A measurement of $\Delta m_t=200$ MeV for fixed $M_W$ would constrain a 100 GeV SM Higgs mass within about $\pm 2$ GeV, while $\Delta M_W=6$ MeV for fixed $m_t$ would constrain $m_h$ to about $\pm 10$ GeV.
hep-ph/9703452
Manuel Drees
Abdelhak Djouadi (LPM, Montpellier, France) and Manuel Drees (APCTP, Seoul, Korea)
Higgs Boson Decays into Light Gravitinos
11 pages, 4 embedded figures; LaTeX with equation.sty and epsf.sty
Phys.Lett. B407 (1997) 243-249
10.1016/S0370-2693(97)00670-9
APCTP 97-05, PM 97-05
hep-ph
null
We study decays of the neutral and charged Higgs bosons of the minimal supersymmetric standard model into a very light gravitino and a neutralino or chargino. Present experimental constraints already imply that the lighter scalar Higgs boson can only have a very small branching ratio into this mode. However, if the gravitino mass is below $\sim 0.5$ eV, the heavier neutral and charged Higgs boson decays into a gravitino can be important or even dominant. We discuss the resulting signature for associate production of the heavy CP-even and the CP-odd states at future $e^+ e^-$ colliders, and comment on Higgs boson production at hadron colliders.
[ { "created": "Sat, 29 Mar 1997 05:58:35 GMT", "version": "v1" } ]
2009-10-30
[ [ "Djouadi", "Abdelhak", "", "LPM, Montpellier, France" ], [ "Drees", "Manuel", "", "APCTP,\n Seoul, Korea" ] ]
We study decays of the neutral and charged Higgs bosons of the minimal supersymmetric standard model into a very light gravitino and a neutralino or chargino. Present experimental constraints already imply that the lighter scalar Higgs boson can only have a very small branching ratio into this mode. However, if the gravitino mass is below $\sim 0.5$ eV, the heavier neutral and charged Higgs boson decays into a gravitino can be important or even dominant. We discuss the resulting signature for associate production of the heavy CP-even and the CP-odd states at future $e^+ e^-$ colliders, and comment on Higgs boson production at hadron colliders.
1901.00151
Dmitry V. Naumov
Dmitry V.Naumov
Sterile Neutrino. A short introduction
contribution to VLVnT2018 Conference
null
10.1051/epjconf/201920704004
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This is a pedagogical introduction to the main concepts of the sterile neutrino - a hypothetical particle, coined to resolve some anomalies in neutrino data and retain consistency with observed widths of the $W$ and $Z$ bosons. We briefly review existing anomalies and the oscillation parameters that best describe these data. We discuss in more detail how sterile neutrino can be observed, as well as the consequences of its possible existence. In particular, we pay attention to a possible loss of coherence in a model of neutrino oscillations with sterile neutrinos, where this effect might be of a major importance with respect to the 3$\nu$ model. The current status of searches for a sterile neutrino state is also briefly reviewed.
[ { "created": "Tue, 1 Jan 2019 13:10:21 GMT", "version": "v1" } ]
2019-05-22
[ [ "Naumov", "Dmitry V.", "" ] ]
This is a pedagogical introduction to the main concepts of the sterile neutrino - a hypothetical particle, coined to resolve some anomalies in neutrino data and retain consistency with observed widths of the $W$ and $Z$ bosons. We briefly review existing anomalies and the oscillation parameters that best describe these data. We discuss in more detail how sterile neutrino can be observed, as well as the consequences of its possible existence. In particular, we pay attention to a possible loss of coherence in a model of neutrino oscillations with sterile neutrinos, where this effect might be of a major importance with respect to the 3$\nu$ model. The current status of searches for a sterile neutrino state is also briefly reviewed.
hep-ph/9409254
Jean-Bruno Erismann
J. Soffer
Positivity Constraints for Spin-Dependent Parton Distributions
8 pages,CPT-94/P.3059,LaTex,3 fig available on cpt.univ-mrs.fr directory pub/preprints/94/fundamental-interactions/94-P.3059
Phys.Rev.Lett.74:1292-1294,1995
10.1103/PhysRevLett.74.1292
null
hep-ph
null
We derive new positivity constraints on the spin-dependent structure functions of the nucleon. These model independent results reduce conside\-rably their domain of allowed values, in particular for the chiral-odd parton distribution $h_1 (x)$.
[ { "created": "Thu, 8 Sep 1994 08:44:47 GMT", "version": "v1" }, { "created": "Wed, 19 Oct 1994 08:14:45 GMT", "version": "v2" } ]
2010-11-01
[ [ "Soffer", "J.", "" ] ]
We derive new positivity constraints on the spin-dependent structure functions of the nucleon. These model independent results reduce conside\-rably their domain of allowed values, in particular for the chiral-odd parton distribution $h_1 (x)$.
2406.16504
Luis Roca
E. Oset, L. Roca, M. Whitehead
Production of pentaquarks with hidden charm and double strangeness in $\Xi_b$ and $\Omega_b$ decays
9 pages, 7 figures
null
null
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
Recently, several pentaquark states $P_{css}$, with global flavor $\bar c c s s n$, have been predicted within a theoretical framework based on unitary coupled channels. We study theoretically the feasibility to observe the $P_{css}$ with $I(J^P)=\frac{1}{2}(\frac{1}{2}^-)$ in the decays $\Xi_b^0\to \eta \eta_c \Xi^0$ and $\Omega_b^-\to K^- \eta_c \Xi^0$. Indeed, within the model, the $\eta_c \Xi^0$ channel is the lowest mass pseudoscalar-baryon channel to which this pentaquark state couples, thus we can expect to observe its signal in the $\eta_c \Xi^0$ invariant mass distribution of the mentioned decays. We identify the dominant weak decay processes and then implement the hadronization into the different meson-baryon channels in the final state, linked by flavor symmetry. The dominant meson-baryon final state interaction is then implemented to generate the full amplitude, implicitly accounting for the dynamical emergence of the pentaquark states. We obtain a clear Breit-Wigner-like resonant signal in the spectrum of the $\Omega_b^-$ decay, exceeding that in the $\Xi_b^0$ decay by two to three orders of magnitude. In the case of the latter decay, the resonant state would manifest as a significant dip in the spectrum. We study the feasibility of searching for these $b$-hadron decay modes and analysing their resonant components using the current and future data samples from the LHCb experiment.
[ { "created": "Mon, 24 Jun 2024 10:17:04 GMT", "version": "v1" } ]
2024-06-25
[ [ "Oset", "E.", "" ], [ "Roca", "L.", "" ], [ "Whitehead", "M.", "" ] ]
Recently, several pentaquark states $P_{css}$, with global flavor $\bar c c s s n$, have been predicted within a theoretical framework based on unitary coupled channels. We study theoretically the feasibility to observe the $P_{css}$ with $I(J^P)=\frac{1}{2}(\frac{1}{2}^-)$ in the decays $\Xi_b^0\to \eta \eta_c \Xi^0$ and $\Omega_b^-\to K^- \eta_c \Xi^0$. Indeed, within the model, the $\eta_c \Xi^0$ channel is the lowest mass pseudoscalar-baryon channel to which this pentaquark state couples, thus we can expect to observe its signal in the $\eta_c \Xi^0$ invariant mass distribution of the mentioned decays. We identify the dominant weak decay processes and then implement the hadronization into the different meson-baryon channels in the final state, linked by flavor symmetry. The dominant meson-baryon final state interaction is then implemented to generate the full amplitude, implicitly accounting for the dynamical emergence of the pentaquark states. We obtain a clear Breit-Wigner-like resonant signal in the spectrum of the $\Omega_b^-$ decay, exceeding that in the $\Xi_b^0$ decay by two to three orders of magnitude. In the case of the latter decay, the resonant state would manifest as a significant dip in the spectrum. We study the feasibility of searching for these $b$-hadron decay modes and analysing their resonant components using the current and future data samples from the LHCb experiment.
2211.07071
Cheng Zhang
Cheng Zhang, Qian-Shun Dai and Ding Yu Shao
Azimuthal decorrelation for photon induced dijet production in ultra-peripheral collisions of heavy ions
20 pages, 5 figures
J. High Energ. Phys. 2023, 2 (2023)
10.1007/JHEP02(2023)002
null
hep-ph hep-ex nucl-th
http://creativecommons.org/licenses/by/4.0/
We study the azimuthal angular decorrelation of the dijet production via photon fusion in ultra-peripheral heavy ion collisions. The impact parameter dependent cross section of quark-antiquark pairs production is derived using the equivalent photon approximation, and the contribution from final-state QCD radiations to the azimuthal angular distribution are calculated within Soft-Collinear Effective Theory. We carry out the QCD resummation of large logarithms of the azimuthal angle as well as the jet radius at next-to-leading logarithmic accuracy. In the end we present the normalized differential cross section for azimuthal decorrelation of the dijet pair and find that our results are consistent with the measurements reported by the ATLAS collaboration.
[ { "created": "Mon, 14 Nov 2022 02:29:17 GMT", "version": "v1" }, { "created": "Thu, 2 Feb 2023 04:43:53 GMT", "version": "v2" } ]
2023-02-03
[ [ "Zhang", "Cheng", "" ], [ "Dai", "Qian-Shun", "" ], [ "Shao", "Ding Yu", "" ] ]
We study the azimuthal angular decorrelation of the dijet production via photon fusion in ultra-peripheral heavy ion collisions. The impact parameter dependent cross section of quark-antiquark pairs production is derived using the equivalent photon approximation, and the contribution from final-state QCD radiations to the azimuthal angular distribution are calculated within Soft-Collinear Effective Theory. We carry out the QCD resummation of large logarithms of the azimuthal angle as well as the jet radius at next-to-leading logarithmic accuracy. In the end we present the normalized differential cross section for azimuthal decorrelation of the dijet pair and find that our results are consistent with the measurements reported by the ATLAS collaboration.
hep-ph/0408198
Pankaj Jain
Sudeep Das, Pankaj Jain, John P. Ralston and Rajib Saha
Probing Light Pseudoscalars with Light: Propagation, Resonance and Spontaneous Polarization
41 pages, 7 figures, revised version
JCAP 0506 (2005) 002
10.1088/1475-7516/2005/06/002
null
hep-ph astro-ph
null
Radiation propagating over cosmological distances can probe light weakly interacting pseudoscalar (or scalar) particles. The existence of a spin-0 field changes the dynamical symmetries of electrodynamics. It predicts spontaneous generation of polarization of electromagnetic waves due to mode mixing in the presence of background magnetic field.We illustrate this by calculations of propagation in a uniform medium, as well as in a slowly varying background medium, and finally with resonant mixing. Highly complicated correlations between different Stokes parameters are predicted depending on the parameter regimes. The polarization of propagating waves shows interesting and complex dependence on frequency, the distance of propagation, coupling constants, and parameters of the background medium such as the plasma density and the magnetic field strength. For the first time we study the resonant mixing of electromagnetic waves with the scalar field, which occurs when the background plasma frequency becomes equal to the mass of the scalar field at some point along the path. Dynamical effects are found to be considerably enhanced in this case. We also formulate the condition under which the adiabatic approximation can be used consistently, and find caveats about comparing different frequency regimes.
[ { "created": "Wed, 18 Aug 2004 04:07:15 GMT", "version": "v1" }, { "created": "Wed, 13 Oct 2004 06:43:36 GMT", "version": "v2" }, { "created": "Fri, 27 May 2005 04:49:23 GMT", "version": "v3" }, { "created": "Thu, 9 Aug 2007 09:40:54 GMT", "version": "v4" } ]
2009-11-10
[ [ "Das", "Sudeep", "" ], [ "Jain", "Pankaj", "" ], [ "Ralston", "John P.", "" ], [ "Saha", "Rajib", "" ] ]
Radiation propagating over cosmological distances can probe light weakly interacting pseudoscalar (or scalar) particles. The existence of a spin-0 field changes the dynamical symmetries of electrodynamics. It predicts spontaneous generation of polarization of electromagnetic waves due to mode mixing in the presence of background magnetic field.We illustrate this by calculations of propagation in a uniform medium, as well as in a slowly varying background medium, and finally with resonant mixing. Highly complicated correlations between different Stokes parameters are predicted depending on the parameter regimes. The polarization of propagating waves shows interesting and complex dependence on frequency, the distance of propagation, coupling constants, and parameters of the background medium such as the plasma density and the magnetic field strength. For the first time we study the resonant mixing of electromagnetic waves with the scalar field, which occurs when the background plasma frequency becomes equal to the mass of the scalar field at some point along the path. Dynamical effects are found to be considerably enhanced in this case. We also formulate the condition under which the adiabatic approximation can be used consistently, and find caveats about comparing different frequency regimes.
1805.01904
Martin Bauer
Martin Bauer, Sascha Diefenbacher, Tilman Plehn, Michael Russell and Daniel A. Camargo
Dark Matter in Anomaly-Free Gauge Extensions
25 pages plus appendix, 14 figures
SciPost Phys. 5, 036 (2018)
10.21468/SciPostPhys.5.4.036
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A consistent model for vector mediators to dark matter needs to be anomaly-free and include a scalar mode from mass generation. For the leading U(1) extensions we review the structure and constraints, including kinetic mixing at loop level. The thermal relic density suggests that the vector and scalar masses are similar. For the LHC we combine a $Z'$ shape analysis with mono-jets. For the latter, we find that a shape analysis offers significant improvement over existing cut-and-count approaches. Direct detection limits strongly constrain the kinetic mixing angle and we propose a $\ell^+\ell^- E_T$ search strategy based on the scalar mediator.
[ { "created": "Fri, 4 May 2018 18:02:03 GMT", "version": "v1" }, { "created": "Fri, 25 May 2018 13:43:12 GMT", "version": "v2" }, { "created": "Mon, 20 Aug 2018 10:54:40 GMT", "version": "v3" } ]
2018-10-24
[ [ "Bauer", "Martin", "" ], [ "Diefenbacher", "Sascha", "" ], [ "Plehn", "Tilman", "" ], [ "Russell", "Michael", "" ], [ "Camargo", "Daniel A.", "" ] ]
A consistent model for vector mediators to dark matter needs to be anomaly-free and include a scalar mode from mass generation. For the leading U(1) extensions we review the structure and constraints, including kinetic mixing at loop level. The thermal relic density suggests that the vector and scalar masses are similar. For the LHC we combine a $Z'$ shape analysis with mono-jets. For the latter, we find that a shape analysis offers significant improvement over existing cut-and-count approaches. Direct detection limits strongly constrain the kinetic mixing angle and we propose a $\ell^+\ell^- E_T$ search strategy based on the scalar mediator.
hep-ph/9504279
Fabian Franke
F. Franke and H. Fraas
Mass Bounds for the Neutral Higgs Bosons in the Next-To-Minimal Supersymmetric Standard Model
9 pages, LATEX, 6 figures (not included). The complete paper (including figures) can be obtained via anonymous ftp at ftp://ftp.physik.uni-wuerzburg.de/pub/preprint/WUE-ITP-95-003.ps.gz
Phys.Lett. B353 (1995) 234-242
10.1016/0370-2693(95)00588-C
WUE-ITP-95-003
hep-ph
null
In the Next--To--Minimal Supersymmetric Standard Model (NMSSM), the Higgs and neutralino/chargino sectors are strongly correlated by four common parameters at tree level. Therefore we analyze the experimental data from both the search for Higgs bosons as well as for neutralinos and charginos at LEP 100 in order to constrain the parameter space and the masses of the neutral Higgs particles in the NMSSM. We find that small singlet vacuum expectation values are ruled out, but a massless neutral Higgs scalar and pseudoscalar is not excluded for most of the parameter space of the NMSSM. Improved limits from the neutralino/chargino search at LEP 200, however, may lead to nonvanishing lower Higgs mass bounds.
[ { "created": "Tue, 11 Apr 1995 12:25:09 GMT", "version": "v1" } ]
2009-10-28
[ [ "Franke", "F.", "" ], [ "Fraas", "H.", "" ] ]
In the Next--To--Minimal Supersymmetric Standard Model (NMSSM), the Higgs and neutralino/chargino sectors are strongly correlated by four common parameters at tree level. Therefore we analyze the experimental data from both the search for Higgs bosons as well as for neutralinos and charginos at LEP 100 in order to constrain the parameter space and the masses of the neutral Higgs particles in the NMSSM. We find that small singlet vacuum expectation values are ruled out, but a massless neutral Higgs scalar and pseudoscalar is not excluded for most of the parameter space of the NMSSM. Improved limits from the neutralino/chargino search at LEP 200, however, may lead to nonvanishing lower Higgs mass bounds.
1407.5956
A. H. Rezaeian
Amir H. Rezaeian
b-CGC versus IP-Sat and high precision combined HERA data
7 pages, 10 figures. To appear in proceedings of DIS 2014, XXII. International Workshop on Deep-Inelastic Scattering and Related Subjects, 28 April - 2 May 2014, Warsaw, Poland
null
null
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Impact-Parameter dependent Color Glass Condensate (b-CGC) and Saturation (IP-Sat) dipole models incorporate key features of small-x physics properties and match smoothly to the perturbative QCD regime at large $Q^2$ for a given $x$. Although both models include saturation effects and depend on impact-parameter, the former is based on the non-linear BK equation, while the latter is based on DGLAP evolution. After confronting the models to the recently released high precision combined HERA data, we show that in both models, the typical impact-parameter probed in the total $\gamma^{*}p$ cross-section is about $b\approx 2\div 3\,\text{GeV}^{-1}$ and the proton saturation scale is $Q_S<1$ GeV in HERA kinematics. We show that most features of inclusive DIS and exclusive diffractive data at HERA are correctly reproduced in both models. Nevertheless, the b-CGC and the IP-Sat models give significantly different predictions beyond the current HERA kinematics for the structure functions at very low x and high virtualities $Q^2$, and for the exclusive diffractive vector meson and DVCS production at high $t$.
[ { "created": "Tue, 22 Jul 2014 17:43:30 GMT", "version": "v1" }, { "created": "Wed, 23 Jul 2014 18:51:25 GMT", "version": "v2" } ]
2014-07-24
[ [ "Rezaeian", "Amir H.", "" ] ]
The Impact-Parameter dependent Color Glass Condensate (b-CGC) and Saturation (IP-Sat) dipole models incorporate key features of small-x physics properties and match smoothly to the perturbative QCD regime at large $Q^2$ for a given $x$. Although both models include saturation effects and depend on impact-parameter, the former is based on the non-linear BK equation, while the latter is based on DGLAP evolution. After confronting the models to the recently released high precision combined HERA data, we show that in both models, the typical impact-parameter probed in the total $\gamma^{*}p$ cross-section is about $b\approx 2\div 3\,\text{GeV}^{-1}$ and the proton saturation scale is $Q_S<1$ GeV in HERA kinematics. We show that most features of inclusive DIS and exclusive diffractive data at HERA are correctly reproduced in both models. Nevertheless, the b-CGC and the IP-Sat models give significantly different predictions beyond the current HERA kinematics for the structure functions at very low x and high virtualities $Q^2$, and for the exclusive diffractive vector meson and DVCS production at high $t$.
1003.1798
Douglas Gingrich Mr.
Douglas M. Gingrich
Noncommutative geometry inspired black holes in higher dimensions at the LHC
21 pages, 7 figures
JHEP 1005:022,2010
10.1007/JHEP05(2010)022
null
hep-ph gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
When embedding models of noncommutative geometry inspired black holes into the peridium of large extra dimensions, it is natural to relate the noncommutativity scale to the higher-dimensional Planck scale. If the Planck scale is of the order of a TeV, noncommutative geometry inspired black holes could become accessible to experiments. In this paper, we present a detailed phenomenological study of the production and decay of these black holes at the Large Hadron Collider (LHC). Noncommutative inspired black holes are relatively cold and can be well described by the microcanonical ensemble during their entire decay. One of the main consequences of the model is the existence of a black hole remnant. The mass of the black hole remnant increases with decreasing mass scale associated with noncommutative and decreasing number of dimensions. The experimental signatures could be quite different from previous studies of black holes and remnants at the LHC since the mass of the remnant could be well above the Planck scale. Although the black hole remnant can be very heavy, and perhaps even charged, it could result in very little activity in the central detectors of the LHC experiments, when compared to the usual anticipated black hole signatures. If this type of noncommutative inspired black hole can be produced and detected, it would result in an additional mass threshold above the Planck scale at which new physics occurs.
[ { "created": "Tue, 9 Mar 2010 06:53:20 GMT", "version": "v1" } ]
2014-11-20
[ [ "Gingrich", "Douglas M.", "" ] ]
When embedding models of noncommutative geometry inspired black holes into the peridium of large extra dimensions, it is natural to relate the noncommutativity scale to the higher-dimensional Planck scale. If the Planck scale is of the order of a TeV, noncommutative geometry inspired black holes could become accessible to experiments. In this paper, we present a detailed phenomenological study of the production and decay of these black holes at the Large Hadron Collider (LHC). Noncommutative inspired black holes are relatively cold and can be well described by the microcanonical ensemble during their entire decay. One of the main consequences of the model is the existence of a black hole remnant. The mass of the black hole remnant increases with decreasing mass scale associated with noncommutative and decreasing number of dimensions. The experimental signatures could be quite different from previous studies of black holes and remnants at the LHC since the mass of the remnant could be well above the Planck scale. Although the black hole remnant can be very heavy, and perhaps even charged, it could result in very little activity in the central detectors of the LHC experiments, when compared to the usual anticipated black hole signatures. If this type of noncommutative inspired black hole can be produced and detected, it would result in an additional mass threshold above the Planck scale at which new physics occurs.
hep-ph/0504175
Philipp Hagler
M. Diehl, Ph. Hagler
Spin densities in the transverse plane and generalized transversity distributions
23 pages, 6 eps-figures
Eur.Phys.J.C44:87-101,2005
10.1140/epjc/s2005-02342-6
null
hep-ph hep-lat
null
We show how generalized quark distributions in the nucleon describe the density of polarized quarks in the impact parameter plane, both for longitudinal and transverse polarization of the quark and the nucleon. This density representation entails positivity bounds including chiral-odd distributions, which tighten the known bounds in the chiral-even sector. Using the quark equations of motion, we derive relations between the moments of chiral-odd generalized parton distributions of twist two and twist three. We exhibit the analogy between polarized quark distributions in impact parameter space and transverse momentum dependent distribution functions.
[ { "created": "Wed, 20 Apr 2005 13:08:02 GMT", "version": "v1" } ]
2009-01-07
[ [ "Diehl", "M.", "" ], [ "Hagler", "Ph.", "" ] ]
We show how generalized quark distributions in the nucleon describe the density of polarized quarks in the impact parameter plane, both for longitudinal and transverse polarization of the quark and the nucleon. This density representation entails positivity bounds including chiral-odd distributions, which tighten the known bounds in the chiral-even sector. Using the quark equations of motion, we derive relations between the moments of chiral-odd generalized parton distributions of twist two and twist three. We exhibit the analogy between polarized quark distributions in impact parameter space and transverse momentum dependent distribution functions.
hep-ph/0206012
Alexei Prokudin
V. A. Petrov, E. Predazzi, A. Prokudin
Coulomb Interference in High-Energy pp and pbar p Scattering
20 pages, 16 figures
Eur.Phys.J.C28:525-533,2003
10.1140/epjc/s2003-01191-7
null
hep-ph
null
An analysis of the Coulombic amplitude and its interference with the nuclear amplitude which is driven by the three-component Pomeron is presented. It is shown that different approaches towards the Coulomb phase evaluation give approximately uniform result at all energies and the difference is negligible at RHIC and LHC energies. We show that the use of the amplitude which was fitted to accomodate nucleon data only (in the region 0.01 < |t| < 14.5 (GeV^2)) combined with the Coulomb amplitude, reproduces the existing data in the Coulomb interference domain quite accurately without any adjustement of the parameters. As a consequence, we predict the differential cross section in the region of the Coulomb nucleon interference for both RHIC and LHC energies.
[ { "created": "Mon, 3 Jun 2002 14:04:46 GMT", "version": "v1" } ]
2011-09-13
[ [ "Petrov", "V. A.", "" ], [ "Predazzi", "E.", "" ], [ "Prokudin", "A.", "" ] ]
An analysis of the Coulombic amplitude and its interference with the nuclear amplitude which is driven by the three-component Pomeron is presented. It is shown that different approaches towards the Coulomb phase evaluation give approximately uniform result at all energies and the difference is negligible at RHIC and LHC energies. We show that the use of the amplitude which was fitted to accomodate nucleon data only (in the region 0.01 < |t| < 14.5 (GeV^2)) combined with the Coulomb amplitude, reproduces the existing data in the Coulomb interference domain quite accurately without any adjustement of the parameters. As a consequence, we predict the differential cross section in the region of the Coulomb nucleon interference for both RHIC and LHC energies.
1512.04356
Giuliano Panico
Oleksii Matsedonskyi, Giuliano Panico and Andrea Wulzer
Top Partners Searches and Composite Higgs Models
32 pages, 15 figures
null
10.1007/JHEP04(2016)003
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Colored fermionic partners of the top quark are well-known signatures of the Composite Higgs scenario and for this reason they have been and will be subject of an intensive experimental study at the LHC. Performing an assessment of the theoretical implications of this experimental effort is the goal of the present paper. We proceed by analyzing a set of simple benchmark models, characterized by simple two-dimensional parameter spaces where the results of the searches are conveniently visualized and their impact quantified. We only draw exclusion contours, in the hypothesis of no signal, but of course our formalism could equally well be used to report discoveries in a theoretically useful format.
[ { "created": "Mon, 14 Dec 2015 15:08:11 GMT", "version": "v1" } ]
2016-05-04
[ [ "Matsedonskyi", "Oleksii", "" ], [ "Panico", "Giuliano", "" ], [ "Wulzer", "Andrea", "" ] ]
Colored fermionic partners of the top quark are well-known signatures of the Composite Higgs scenario and for this reason they have been and will be subject of an intensive experimental study at the LHC. Performing an assessment of the theoretical implications of this experimental effort is the goal of the present paper. We proceed by analyzing a set of simple benchmark models, characterized by simple two-dimensional parameter spaces where the results of the searches are conveniently visualized and their impact quantified. We only draw exclusion contours, in the hypothesis of no signal, but of course our formalism could equally well be used to report discoveries in a theoretically useful format.
hep-ph/9511445
Brian Wright
Paul H. Frampton (1), Bettina Keszthelyi (1), Brian D. Wright (1) and Thomas W. Kephart (2) ((1) Institute of Field Physics, University of North Carolina, Chapel Hill, (2) Department of Physics and Astronomy, Vanderbilt University )
Constraining $\alpha_s(M_Z)$ from the Hidden Sector
12 pages (23k), in ReVTeX plus 3 postscript figures (27k), Submitted to Physical Review Letters
null
null
IFP-714-UNC, VAND-TH-95-5
hep-ph
null
By including the effects of superstring thresholds, we reconsider minimal string unification together with the requirement of producing a supersymmetry-breaking gluino condensate in the hidden sector. This gives, for examples of phenomenologically-viable $Z_8'$ and other related orbifolds, the constraint that $0.1215 \leq \alpha_s(M_Z) \leq 0.1270$. In such models, a hidden photino can be a source of cosmological dark matter detectable by gravitational microlensing.
[ { "created": "Wed, 29 Nov 1995 01:36:40 GMT", "version": "v1" }, { "created": "Wed, 29 Nov 1995 06:43:39 GMT", "version": "v2" } ]
2008-02-03
[ [ "Frampton", "Paul H.", "" ], [ "Keszthelyi", "Bettina", "" ], [ "Wright", "Brian D.", "" ], [ "Kephart", "Thomas W.", "" ] ]
By including the effects of superstring thresholds, we reconsider minimal string unification together with the requirement of producing a supersymmetry-breaking gluino condensate in the hidden sector. This gives, for examples of phenomenologically-viable $Z_8'$ and other related orbifolds, the constraint that $0.1215 \leq \alpha_s(M_Z) \leq 0.1270$. In such models, a hidden photino can be a source of cosmological dark matter detectable by gravitational microlensing.
1205.6569
Per Osland
L. Basso, A. Lipniacka, F. Mahmoudi, S. Moretti, P. Osland, G. M. Pruna, M. Purmohammadi
Probing the charged Higgs boson at the LHC in the CP-violating type-II 2HDM
37 pages, 16 figures; v2 updated treatment of LHC constraints
JHEP 1211 (2012) 011
10.1007/JHEP11(2012)011
CERN-PH-TH/2012-068; FR-PHENO-2012-005; SHEP-12-06
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a phenomenological study of a CP-violating two-Higgs-doublet Model with type-II Yukawa couplings at the Large Hadron Collider (LHC). In the light of recent LHC data, we focus on the parameter space that survives the current and past experimental constraints as well as theoretical bounds on the model. Once the phenomenological scenario is set, we analyse the scope of the LHC in exploring this model through the discovery of a charged Higgs boson produced in association with a W boson, with the former decaying into the lightest neutral Higgs and a second W state, altogether yielding a b\bar b W^+W^- signature, of which we exploit the W^+W^- semileptonic decays.
[ { "created": "Wed, 30 May 2012 07:59:32 GMT", "version": "v1" }, { "created": "Mon, 27 Aug 2012 10:05:19 GMT", "version": "v2" } ]
2012-11-13
[ [ "Basso", "L.", "" ], [ "Lipniacka", "A.", "" ], [ "Mahmoudi", "F.", "" ], [ "Moretti", "S.", "" ], [ "Osland", "P.", "" ], [ "Pruna", "G. M.", "" ], [ "Purmohammadi", "M.", "" ] ]
We present a phenomenological study of a CP-violating two-Higgs-doublet Model with type-II Yukawa couplings at the Large Hadron Collider (LHC). In the light of recent LHC data, we focus on the parameter space that survives the current and past experimental constraints as well as theoretical bounds on the model. Once the phenomenological scenario is set, we analyse the scope of the LHC in exploring this model through the discovery of a charged Higgs boson produced in association with a W boson, with the former decaying into the lightest neutral Higgs and a second W state, altogether yielding a b\bar b W^+W^- signature, of which we exploit the W^+W^- semileptonic decays.
2402.04184
Wei-Chih Huang
Bhaskar Dutta, Wei-Chih Huang, Doojin Kim, Jayden L. Newstead, Jong-Chul Park, and Iman Shaukat Ali
Exciting Prospects for Dark Matter at Large-Volume Neutrino Detectors
7 pages, 4 figures
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose a new approach to search for light dark matter (DM) in the range of keV-GeV via inelastic nucleus scattering at large-volume neutrino detectors such as Borexino, DUNE, JUNO, and Hyper-K. The approach uses inelastic nuclear scattering of cosmic-ray boosted DM, enabling a low-background search for DM in these experiments. The large neutrino detectors with higher threshold can be used since the nuclear deexcitation lines are $O(10)$ MeV. Using a hadrophilic dark-gauge-boson-portal model as a benchmark, we show that the nuclear inelastic channels generally provide better sensitivity than the elastic scattering for a large region of light DM parameter space.
[ { "created": "Tue, 6 Feb 2024 17:44:09 GMT", "version": "v1" } ]
2024-02-07
[ [ "Dutta", "Bhaskar", "" ], [ "Huang", "Wei-Chih", "" ], [ "Kim", "Doojin", "" ], [ "Newstead", "Jayden L.", "" ], [ "Park", "Jong-Chul", "" ], [ "Ali", "Iman Shaukat", "" ] ]
We propose a new approach to search for light dark matter (DM) in the range of keV-GeV via inelastic nucleus scattering at large-volume neutrino detectors such as Borexino, DUNE, JUNO, and Hyper-K. The approach uses inelastic nuclear scattering of cosmic-ray boosted DM, enabling a low-background search for DM in these experiments. The large neutrino detectors with higher threshold can be used since the nuclear deexcitation lines are $O(10)$ MeV. Using a hadrophilic dark-gauge-boson-portal model as a benchmark, we show that the nuclear inelastic channels generally provide better sensitivity than the elastic scattering for a large region of light DM parameter space.
0712.0145
Sukanta Dutta
Sukanta Dutta (1) and Ashok Goyal (2) ((1) SGTB Khalsa College, University of Delhi India, (2)Department of Physics and Astrophysics, University of Delhi, India.)
Constraints on Astro-unparticle Physics from SN 1987A
12 pages, 2 postscript figures
JCAP0803:027,2008
10.1088/1475-7516/2008/03/027
null
hep-ph
null
SN 1987A observations have been used to place constraints on the interactions between standard model particles and unparticles. In this study we calculate the energy loss from the supernovae core through scalar, pseudo scalar, vector, pseudo vector unparticle emission from nuclear bremsstrahlung for degenerate nuclear matter interacting through one pion exchange. In order to examine the constraints on $d_{\cal U}=1$ we considered the emission of scalar, pseudo scalar, vector, pseudo vector and tensor through the pair annihilation process $e^+e^-\to {\cal U} \gamma $. In addition we have re-examined other pair annihilation processes. The most stringent bounds on the dimensionless coupling constants for $d_{\cal U} =1$ and $\Lambda_{\cal U}= m_Z$ are obtained from nuclear bremsstrahlung process for the pseudo scalar and pseudo-vector couplings $\bigl|\lambda^{\cal P}_{0,1}\bigr|\leq 4\times 10^{-11}$ and for tensor interaction, the best limit on dimensionless coupling is obtained from $e^+ e^-\to {\cal U} \gamma$ and we get $\bigl|\lambda^{\cal T}\bigr| \leq 6\times 10^{-6}$.
[ { "created": "Mon, 3 Dec 2007 19:01:25 GMT", "version": "v1" }, { "created": "Tue, 15 Jan 2008 16:45:41 GMT", "version": "v2" }, { "created": "Wed, 16 Jan 2008 11:28:11 GMT", "version": "v3" } ]
2008-11-26
[ [ "Dutta", "Sukanta", "" ], [ "Goyal", "Ashok", "" ] ]
SN 1987A observations have been used to place constraints on the interactions between standard model particles and unparticles. In this study we calculate the energy loss from the supernovae core through scalar, pseudo scalar, vector, pseudo vector unparticle emission from nuclear bremsstrahlung for degenerate nuclear matter interacting through one pion exchange. In order to examine the constraints on $d_{\cal U}=1$ we considered the emission of scalar, pseudo scalar, vector, pseudo vector and tensor through the pair annihilation process $e^+e^-\to {\cal U} \gamma $. In addition we have re-examined other pair annihilation processes. The most stringent bounds on the dimensionless coupling constants for $d_{\cal U} =1$ and $\Lambda_{\cal U}= m_Z$ are obtained from nuclear bremsstrahlung process for the pseudo scalar and pseudo-vector couplings $\bigl|\lambda^{\cal P}_{0,1}\bigr|\leq 4\times 10^{-11}$ and for tensor interaction, the best limit on dimensionless coupling is obtained from $e^+ e^-\to {\cal U} \gamma$ and we get $\bigl|\lambda^{\cal T}\bigr| \leq 6\times 10^{-6}$.
0808.0650
Andre Rubbia
T. Kajita, S.B. Kim, A.Rubbia
Summary of the 3rd International Workshop on a Far Detector in Korea for the J-PARC Beam
10 pages, 5 figures, to appear in Proc. 3rd International Workshop on a Far Detector in Korea for the J-PARC Neutrino Beam, Univ. of Tokyo, Tokyo, Japan, Sep.30 - Oct. 1, 2007
null
null
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The 3rd International Workshop on a Far Detector in Korea for the J-PARC Neutrino Beam was held at the Hongo Campus of Tokyo University, Tokyo, Japan on Sep. 30th and October 1, 2007. Forty seven physicists from Japan and Korea, as well as Europe and USA, participated in the workshop and discussed the physics opportunities offered by the J-PARC conventional neutrino beam detected by a new large underground neutrino detector in Korea. In this paper, we highlight some of the most relevant findings of the workshop.
[ { "created": "Tue, 5 Aug 2008 13:43:29 GMT", "version": "v1" } ]
2008-08-06
[ [ "Kajita", "T.", "" ], [ "Kim", "S. B.", "" ], [ "Rubbia", "A.", "" ] ]
The 3rd International Workshop on a Far Detector in Korea for the J-PARC Neutrino Beam was held at the Hongo Campus of Tokyo University, Tokyo, Japan on Sep. 30th and October 1, 2007. Forty seven physicists from Japan and Korea, as well as Europe and USA, participated in the workshop and discussed the physics opportunities offered by the J-PARC conventional neutrino beam detected by a new large underground neutrino detector in Korea. In this paper, we highlight some of the most relevant findings of the workshop.
hep-ph/9907522
Apostolos Pilaftsis
Ara Ioannisian and Apostolos Pilaftsis
Cumulative Non-Decoupling Effects of Kaluza-Klein Neutrinos in Electroweak Processes
31 pages, LaTeX, to appear in Physical Review D
Phys.Rev. D62 (2000) 066001
10.1103/PhysRevD.62.066001
CERN-TH/99-230, MPI-Th/99-30, FERMILAB-PUB-99/215-T, THES-TP/99-09
hep-ph astro-ph hep-ex hep-th
null
In Kaluza-Klein theories of low-scale quantum gravity, gravitons and isosinglet neutrinos may propagate in a higher-dimensional space with large compact dimensions, whereas all particles of the Standard Model are confined on a (1+3)-dimensional subspace. After compactification of the extra dimensions, the resulting Yukawa couplings of the Kaluza-Klein neutrinos to the lepton doublets become naturally very suppressed by a higher-dimensional volume factor, in agreement with phenomenological observations. We show that one-loop effects induced by Kaluza-Klein neutrinos, albeit tiny individually, act cumulatively in electroweak processes, giving rise to a non-decoupling behaviour for large values of the higher-dimensional Yukawa couplings. Owing to the non-decoupling effects of Kaluza-Klein neutrinos, we can derive stronger constraints on the parameters of the theory that originate from the non-observation of flavour-violating and universality-breaking phenomena, which involve the W and Z bosons, and the e, $\mu$ and $\tau$ leptons.
[ { "created": "Tue, 27 Jul 1999 23:39:49 GMT", "version": "v1" }, { "created": "Thu, 5 Aug 1999 09:35:31 GMT", "version": "v2" }, { "created": "Wed, 19 Apr 2000 22:43:44 GMT", "version": "v3" } ]
2009-10-31
[ [ "Ioannisian", "Ara", "" ], [ "Pilaftsis", "Apostolos", "" ] ]
In Kaluza-Klein theories of low-scale quantum gravity, gravitons and isosinglet neutrinos may propagate in a higher-dimensional space with large compact dimensions, whereas all particles of the Standard Model are confined on a (1+3)-dimensional subspace. After compactification of the extra dimensions, the resulting Yukawa couplings of the Kaluza-Klein neutrinos to the lepton doublets become naturally very suppressed by a higher-dimensional volume factor, in agreement with phenomenological observations. We show that one-loop effects induced by Kaluza-Klein neutrinos, albeit tiny individually, act cumulatively in electroweak processes, giving rise to a non-decoupling behaviour for large values of the higher-dimensional Yukawa couplings. Owing to the non-decoupling effects of Kaluza-Klein neutrinos, we can derive stronger constraints on the parameters of the theory that originate from the non-observation of flavour-violating and universality-breaking phenomena, which involve the W and Z bosons, and the e, $\mu$ and $\tau$ leptons.
hep-ph/9805288
Ivone Albuquerque
Ivone F.M.Albuquerque, Glennys R.Farrar and Edward W.Kolb
Exotic massive hadrons and ultra-high energy cosmic rays
27 pages, 15 figures - fig5b was replaced
Phys.Rev. D59 (1999) 015021
10.1103/PhysRevD.59.015021
FNAL-PUB-98/131-A; EFI-98-15; RU-98-19
hep-ph astro-ph
null
We investigate the proposal that primary cosmic rays of energy above the Greisen-Zatsepin-Kuzmin cutoff are exotic massive strongly interacting particles (uhecrons). We study the properties of air showers produced by uhecrons and find that masses in excess of about 50 GeV are inconsistent with the highest energy event observed. We also estimate that with sufficient statistics a uhecron of mass as low as 10 GeV may be distinguished from a proton.
[ { "created": "Mon, 11 May 1998 21:59:28 GMT", "version": "v1" }, { "created": "Mon, 24 Aug 1998 19:48:47 GMT", "version": "v2" }, { "created": "Fri, 2 Oct 1998 16:34:47 GMT", "version": "v3" } ]
2009-10-31
[ [ "Albuquerque", "Ivone F. M.", "" ], [ "Farrar", "Glennys R.", "" ], [ "Kolb", "Edward W.", "" ] ]
We investigate the proposal that primary cosmic rays of energy above the Greisen-Zatsepin-Kuzmin cutoff are exotic massive strongly interacting particles (uhecrons). We study the properties of air showers produced by uhecrons and find that masses in excess of about 50 GeV are inconsistent with the highest energy event observed. We also estimate that with sufficient statistics a uhecron of mass as low as 10 GeV may be distinguished from a proton.
hep-ph/0309278
Aneesh Manohar
Christian W. Bauer, Christopher Lee, Aneesh V. Manohar, Mark B. Wise
Enhanced Nonperturbative Effects in Z Decays to Hadrons
17 pages. Paper reorganized, and more discussion and results included
Phys.Rev. D70 (2004) 034014
10.1103/PhysRevD.70.034014
null
hep-ph
null
We use soft collinear effective field theory (SCET) to study nonperturbative strong interaction effects in Z decays to hadronic final states that are enhanced in corners of phase space. These occur, for example, in the jet energy distribution for two jet events near E_J=M_Z/2, the thrust distribution near unity and the jet invariant mass distribution near zero. The extent to which such nonperturbative effects for different observables are related is discussed.
[ { "created": "Thu, 25 Sep 2003 19:07:12 GMT", "version": "v1" }, { "created": "Wed, 11 Feb 2004 18:36:34 GMT", "version": "v2" } ]
2009-11-10
[ [ "Bauer", "Christian W.", "" ], [ "Lee", "Christopher", "" ], [ "Manohar", "Aneesh V.", "" ], [ "Wise", "Mark B.", "" ] ]
We use soft collinear effective field theory (SCET) to study nonperturbative strong interaction effects in Z decays to hadronic final states that are enhanced in corners of phase space. These occur, for example, in the jet energy distribution for two jet events near E_J=M_Z/2, the thrust distribution near unity and the jet invariant mass distribution near zero. The extent to which such nonperturbative effects for different observables are related is discussed.
0907.0051
HongWei Ke
Hong-Wei Ke, Zuo Li, Jing-Ling Chen, Yi-Bing Ding and Xue-Qian Li
Symmetry of Dirac Equation and Corresponding Phenomenology
15pages, 3 figures, accepted by International Journal of Modern Physics A
Int.J.Mod.Phys.A25:1123-1134,2010
10.1142/S0217751X1004783X
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It has been suggested that the high symmetries in the Schr\"odinger equation with the Coulomb or harmonic oscillator potentials may remain in the corresponding relativistic Dirac equation. If the principle is correct, in the Dirac equation the potential should have a form as ${(1+\beta)\over 2}V(r)$ where $V(r)$ is ${-e^2\over r}$ for hydrogen atom and $\kappa r^2$ for harmonic oscillator. However, in the case of hydrogen atom, by this combination the spin-orbit coupling term would not exist and it is inconsistent with the observational spectra of hydrogen atom, so that the symmetry of SO(4) must reduce into SU(2). The governing mechanisms QED and QCD which induce potential are vector-like theories, so at the leading order only vector potential exists. However, the higher order effects may cause a scalar fraction. In this work, we show that for QED, the symmetry restoration is very small and some discussions on the symmetry breaking are made. At the end, we briefly discuss the QCD case and indicate that the situation for QCD is much more complicated and interesting.
[ { "created": "Wed, 1 Jul 2009 01:52:48 GMT", "version": "v1" }, { "created": "Tue, 27 Oct 2009 05:57:09 GMT", "version": "v2" } ]
2015-05-13
[ [ "Ke", "Hong-Wei", "" ], [ "Li", "Zuo", "" ], [ "Chen", "Jing-Ling", "" ], [ "Ding", "Yi-Bing", "" ], [ "Li", "Xue-Qian", "" ] ]
It has been suggested that the high symmetries in the Schr\"odinger equation with the Coulomb or harmonic oscillator potentials may remain in the corresponding relativistic Dirac equation. If the principle is correct, in the Dirac equation the potential should have a form as ${(1+\beta)\over 2}V(r)$ where $V(r)$ is ${-e^2\over r}$ for hydrogen atom and $\kappa r^2$ for harmonic oscillator. However, in the case of hydrogen atom, by this combination the spin-orbit coupling term would not exist and it is inconsistent with the observational spectra of hydrogen atom, so that the symmetry of SO(4) must reduce into SU(2). The governing mechanisms QED and QCD which induce potential are vector-like theories, so at the leading order only vector potential exists. However, the higher order effects may cause a scalar fraction. In this work, we show that for QED, the symmetry restoration is very small and some discussions on the symmetry breaking are made. At the end, we briefly discuss the QCD case and indicate that the situation for QCD is much more complicated and interesting.
1311.7425
Matthias Steinhauser
Jonathan Grigo, Jens Hoff, Kirill Melnikov, Matthias Steinhauser
Higgs boson pair production at the LHC: top-quark mass effects at NLO
8 pages, Presented at the 11th International Symposium on Radiative Corrections, RADCOR 2013, 22.-27. September 2013, Lumley Castle, Durham, UK
null
null
TTP13-043, SFB/CPP-13-105
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Higgs boson pair production is considered at next-to-leading order with special emphasis on the effect of a finite top quark mass. It is shown that, unlike for single-Higgs boson production, power-suppressed corrections are numerically important.
[ { "created": "Thu, 28 Nov 2013 21:04:44 GMT", "version": "v1" } ]
2013-12-02
[ [ "Grigo", "Jonathan", "" ], [ "Hoff", "Jens", "" ], [ "Melnikov", "Kirill", "" ], [ "Steinhauser", "Matthias", "" ] ]
Higgs boson pair production is considered at next-to-leading order with special emphasis on the effect of a finite top quark mass. It is shown that, unlike for single-Higgs boson production, power-suppressed corrections are numerically important.
2110.13270
David London
David London and Joaquim Matias
$B$ Flavour Anomalies: 2021 Theoretical Status Report
48 pages, 1 figure. To be published in the Annual Review of Nuclear and Particle Science. Changes: minor modifications of the text, references updated and added
Annual Review of Nuclear and Particle Science, Vol. 72, No. 1, pp. 37-68, 2022
10.1146/annurev-nucl-102020-090209
UdeM-GPP-TH-21-289
hep-ph
http://creativecommons.org/licenses/by/4.0/
At the present time, there are discrepancies with the predictions of the SM in several observables involving $b \to s \ell^+ \ell^-$ and $b \to c \ell^- {\bar\nu}_\ell$ decays. These are the $B$ flavour anomalies. In this review, we summarize the data as of Moriond 2021 and present theoretical new-physics explanations from both a model-independent effective-field-theory point of view and through the building of explicit models. Throughout, we stress the complementarity of these two approaches. We also discuss combined explanations of both $B$ anomalies, and present models that also explain other problems, such as dark matter, $(g-2)_\mu$, neutrino properties, and hadronic anomalies.
[ { "created": "Mon, 25 Oct 2021 21:10:25 GMT", "version": "v1" }, { "created": "Tue, 16 Nov 2021 20:03:58 GMT", "version": "v2" } ]
2022-10-04
[ [ "London", "David", "" ], [ "Matias", "Joaquim", "" ] ]
At the present time, there are discrepancies with the predictions of the SM in several observables involving $b \to s \ell^+ \ell^-$ and $b \to c \ell^- {\bar\nu}_\ell$ decays. These are the $B$ flavour anomalies. In this review, we summarize the data as of Moriond 2021 and present theoretical new-physics explanations from both a model-independent effective-field-theory point of view and through the building of explicit models. Throughout, we stress the complementarity of these two approaches. We also discuss combined explanations of both $B$ anomalies, and present models that also explain other problems, such as dark matter, $(g-2)_\mu$, neutrino properties, and hadronic anomalies.
1602.01330
Nobuhito Maru
Nobuhito Maru
Nambu-Jona-Lasinio Theory and Dynamical Breaking of Supersymmetry
33 pages, 3 figures, a review article prepared for Special Section "Nambu, A Foreteller of Modern Physics (1)" for Progress of Theoretical and Experimental Physics (PTEP). arXiv admin note: substantial text overlap with arXiv:1301.7548
null
10.1093/ptep/ptw018
OCU-PHYS 441
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A recently proposed new mechanism of D-term triggered dynamical supersymmetry breaking is reviewed. Supersymmetry is dynamically broken by nonvanishing D-term vacuum expectation value, which is realized as a nontrivial solution of the gap equation in the self-consistent approximation as in the case of Nambu-Jona-Lasinio model and BCS superconductivity.
[ { "created": "Wed, 3 Feb 2016 15:05:58 GMT", "version": "v1" } ]
2016-05-25
[ [ "Maru", "Nobuhito", "" ] ]
A recently proposed new mechanism of D-term triggered dynamical supersymmetry breaking is reviewed. Supersymmetry is dynamically broken by nonvanishing D-term vacuum expectation value, which is realized as a nontrivial solution of the gap equation in the self-consistent approximation as in the case of Nambu-Jona-Lasinio model and BCS superconductivity.
1204.0863
Bo-Qiang Ma
Tao Peng, Bo-Qiang Ma
Heavy quarkonium 2S states in light-front quark model
5 latex pages, final version for journal publication
Eur.Phys.J. A48 (2012) 66
10.1140/epja/i2012-12066-9
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the charmonium 2S states $\psi'$ and $\eta_c'$, and the bottomonium 2S states $\Upsilon'$ and $\eta_b'$, using the light-front quark model and the 2S state wave function of harmonic oscillator as the approximation of the 2S quarkonium wave function. The decay constants, transition form factors and masses of these mesons are calculated and compared with experimental data. Predictions of quantities such as Br$(\psi' \to \gamma \eta_c')$ are made. The 2S wave function may help us learn more about the structure of these heavy quarkonia.
[ { "created": "Wed, 4 Apr 2012 05:05:58 GMT", "version": "v1" }, { "created": "Fri, 11 May 2012 13:31:18 GMT", "version": "v2" } ]
2012-05-24
[ [ "Peng", "Tao", "" ], [ "Ma", "Bo-Qiang", "" ] ]
We study the charmonium 2S states $\psi'$ and $\eta_c'$, and the bottomonium 2S states $\Upsilon'$ and $\eta_b'$, using the light-front quark model and the 2S state wave function of harmonic oscillator as the approximation of the 2S quarkonium wave function. The decay constants, transition form factors and masses of these mesons are calculated and compared with experimental data. Predictions of quantities such as Br$(\psi' \to \gamma \eta_c')$ are made. The 2S wave function may help us learn more about the structure of these heavy quarkonia.
1510.05462
Maurizio Lusignoli
A. De R\'ujula and M. Lusignoli
The calorimetric spectrum of the electron-capture decay of $^{163}$Ho. A preliminary analysis of the preliminary data
6 pages, 5 figures. Section IV and Fig.3 added. Minor text modifications
null
null
null
hep-ph nucl-th physics.atom-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It is in principle possible to measure directly the electron neutrino mass (or masses and mixing angles) in weak electron-capture decays. The optimal nuclide in this respect is $^{163}$Ho. The favoured experimental technique, currently pursued in various experiments (ECHo, HOLMES and NuMECS) is "calorimetric". The calorimetric energy spectrum is a sum over the unstable vacant orbitals, or "holes", left by the electrons weakly captured by the nucleus. We discuss the current progress in this field and analize the preliminary data. Our conclusion is that, as pointed out by Robertson, the contribution of two-hole states is not negligible. But --in strong contradistinction with the tacit conclusion of previous comparisons of theory and observations-- we find a quite satisfactory agreement. A crucial point is that, in the creation of secondary holes, electron shakeoff and not only electron shakeup must be taken into account.
[ { "created": "Mon, 19 Oct 2015 13:21:47 GMT", "version": "v1" }, { "created": "Sun, 8 Nov 2015 16:36:17 GMT", "version": "v2" } ]
2015-11-10
[ [ "De Rújula", "A.", "" ], [ "Lusignoli", "M.", "" ] ]
It is in principle possible to measure directly the electron neutrino mass (or masses and mixing angles) in weak electron-capture decays. The optimal nuclide in this respect is $^{163}$Ho. The favoured experimental technique, currently pursued in various experiments (ECHo, HOLMES and NuMECS) is "calorimetric". The calorimetric energy spectrum is a sum over the unstable vacant orbitals, or "holes", left by the electrons weakly captured by the nucleus. We discuss the current progress in this field and analize the preliminary data. Our conclusion is that, as pointed out by Robertson, the contribution of two-hole states is not negligible. But --in strong contradistinction with the tacit conclusion of previous comparisons of theory and observations-- we find a quite satisfactory agreement. A crucial point is that, in the creation of secondary holes, electron shakeoff and not only electron shakeup must be taken into account.
0712.4263
Juan Garcia-Bellido
Andres Diaz-Gil, Juan Garcia-Bellido, Margarita Garcia Perez and Antonio Gonzalez-Arroyo
Magnetic field production during preheating at the electroweak scale
4 pages, 6 figures, uses revtex4
Phys.Rev.Lett.100:241301,2008
10.1103/PhysRevLett.100.241301
IFT-UAM/CSIC-07-65
hep-ph astro-ph hep-lat
null
We study the generation of magnetic fields during preheating within an scenario of hybrid inflation at the electroweak (EW) scale. We find that the non-perturbative and strongly out-of-equilibrium process of magnetic field production occurs along the lines predicted by Vachaspati many years ago. The system starts in the false vacuum at the end of inflation, and very quickly the initial quantum fluctuations of the Higgs field get amplified via long wavelength spinodal instabilities. The subsequent nucleation of the random Gaussian Higgs field bubbles (lumps) leads to EW symmetry breaking, and to the creation of $Z$-strings, which soon decay, along with longwave magnetic flux tubes with nontrivial helicity. The intensity and scales in these helical magnetic fields are consistent with their later development into the microgauss fields observed in galaxies and clusters of galaxies.
[ { "created": "Thu, 27 Dec 2007 18:22:33 GMT", "version": "v1" } ]
2008-11-26
[ [ "Diaz-Gil", "Andres", "" ], [ "Garcia-Bellido", "Juan", "" ], [ "Perez", "Margarita Garcia", "" ], [ "Gonzalez-Arroyo", "Antonio", "" ] ]
We study the generation of magnetic fields during preheating within an scenario of hybrid inflation at the electroweak (EW) scale. We find that the non-perturbative and strongly out-of-equilibrium process of magnetic field production occurs along the lines predicted by Vachaspati many years ago. The system starts in the false vacuum at the end of inflation, and very quickly the initial quantum fluctuations of the Higgs field get amplified via long wavelength spinodal instabilities. The subsequent nucleation of the random Gaussian Higgs field bubbles (lumps) leads to EW symmetry breaking, and to the creation of $Z$-strings, which soon decay, along with longwave magnetic flux tubes with nontrivial helicity. The intensity and scales in these helical magnetic fields are consistent with their later development into the microgauss fields observed in galaxies and clusters of galaxies.