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1909.08218
Dorota Strozik-Kotlorz
E. Christova, D. Kotlorz and E. Leader
Towards a model independent extraction of the Boer-Mulders function
6 pages, 4 figures
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
At present, the Boer-Mulders function for a given quark flavour has been extracted from data on semi-inclusive deep inelastic scattering using the simplifying, but theoretically inconsistent, assumption that it is proportional to the Sivers function for each quark flavour. In this paper, using the latest semi-inclusive deep inelastic COMPASS deuteron data on the $\langle\cos\phi_h\rangle$ and $\langle\cos 2 \phi_h\rangle$ asymmetries we extract the collinear $x_B$-dependence of the Boer-Mulders function for the sum of the valence quarks $Q_V=u_V + d_V$ in an essentially model independent way, and find a significant disagreement with the published results. Our analysis also yields interesting information on the transverse momentum dependence of the unpolarized quark distribution and fragmentation functions.
[ { "created": "Wed, 18 Sep 2019 05:57:49 GMT", "version": "v1" } ]
2020-08-17
[ [ "Christova", "E.", "" ], [ "Kotlorz", "D.", "" ], [ "Leader", "E.", "" ] ]
At present, the Boer-Mulders function for a given quark flavour has been extracted from data on semi-inclusive deep inelastic scattering using the simplifying, but theoretically inconsistent, assumption that it is proportional to the Sivers function for each quark flavour. In this paper, using the latest semi-inclusive deep inelastic COMPASS deuteron data on the $\langle\cos\phi_h\rangle$ and $\langle\cos 2 \phi_h\rangle$ asymmetries we extract the collinear $x_B$-dependence of the Boer-Mulders function for the sum of the valence quarks $Q_V=u_V + d_V$ in an essentially model independent way, and find a significant disagreement with the published results. Our analysis also yields interesting information on the transverse momentum dependence of the unpolarized quark distribution and fragmentation functions.
2402.16736
Zhi-Lei She
Zhi-Lei She, An-Ke Lei, Yu-Liang Yan, Dai-Mei Zhou, Wen-Chao Zhang, Hua Zheng, Liang Zheng, Yi-Long Xie, Gang Chen and Ben-Hao Sa
Identifying an $\rm X(3872)$ tetraquark state versus a molecular state by formation time, velocity and temperature in relativistic nuclear collisions
6 pages, 3 figures
Phys. Rev. C 110, 014910 (2024)
10.1103/PhysRevC.110.014910
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The production of exotic hadron $\rm X(3872)$ in $pp$ collisions at $\sqrt{s}=2.76\,\mathrm{TeV}$ is investigated by the parton and hadron cascade model PACIAE in this work. In the simulation the final partonic state (quark matter, QM) and the final hadronic state (hadron matter, HM) are continuously processed and recorded. The $\rm X(3872)$ compact tetraquark state and loose molecular state are, respectively, coalesced and recombined in the QM and HM with the quantum statistical mechanics inspired dynamically constrained phase-space coalescence model. The formation time, velocity and temperature of QM (tetraquark state) and HM (molecular state) are proposed as identifying criteria between the two states. Our results in transverse momentum spectrum and rapidity distribution, etc. show a significant discrepancy between the two states and confirm that they are also valuable criteria identifying the $\rm X(3872)$ compact tetraquark state or molecular state.
[ { "created": "Mon, 26 Feb 2024 16:57:52 GMT", "version": "v1" }, { "created": "Sat, 27 Jul 2024 10:05:34 GMT", "version": "v2" } ]
2024-07-30
[ [ "She", "Zhi-Lei", "" ], [ "Lei", "An-Ke", "" ], [ "Yan", "Yu-Liang", "" ], [ "Zhou", "Dai-Mei", "" ], [ "Zhang", "Wen-Chao", "" ], [ "Zheng", "Hua", "" ], [ "Zheng", "Liang", "" ], [ "Xie", "Yi-Long", "" ], [ "Chen", "Gang", "" ], [ "Sa", "Ben-Hao", "" ] ]
The production of exotic hadron $\rm X(3872)$ in $pp$ collisions at $\sqrt{s}=2.76\,\mathrm{TeV}$ is investigated by the parton and hadron cascade model PACIAE in this work. In the simulation the final partonic state (quark matter, QM) and the final hadronic state (hadron matter, HM) are continuously processed and recorded. The $\rm X(3872)$ compact tetraquark state and loose molecular state are, respectively, coalesced and recombined in the QM and HM with the quantum statistical mechanics inspired dynamically constrained phase-space coalescence model. The formation time, velocity and temperature of QM (tetraquark state) and HM (molecular state) are proposed as identifying criteria between the two states. Our results in transverse momentum spectrum and rapidity distribution, etc. show a significant discrepancy between the two states and confirm that they are also valuable criteria identifying the $\rm X(3872)$ compact tetraquark state or molecular state.
hep-ph/0501064
Brian Cox
B. E. Cox
Double proton tagging at the LHC as a means to discover new physics
Talk given at the 5th Rencontres du Vietnam, 'New Views in Particle Physics' conference, Hanoi, August 2004
null
null
null
hep-ph
null
We review the theoretical and experimental motivations behind recent proposals to add forward proton tagging detectors to the LHC experiments as a means to search for new physics.
[ { "created": "Sun, 9 Jan 2005 14:53:43 GMT", "version": "v1" } ]
2007-05-23
[ [ "Cox", "B. E.", "" ] ]
We review the theoretical and experimental motivations behind recent proposals to add forward proton tagging detectors to the LHC experiments as a means to search for new physics.
2107.11555
Vladimir Dzhunushaliev
Vladimir Dzhunushaliev and Vladimir Folomeev
Axially symmetric particlelike solutions with the flux of a magnetic field in the non-Abelian Proca-Higgs theory
13 pages, 11 figures
null
10.1103/PhysRevD.104.116027
null
hep-ph hep-th
http://creativecommons.org/publicdomain/zero/1.0/
Within the non-Abelian SU(2) Proca-Higgs theory, we study localised axially symmetric solutions possessing a finite field energy. It is shown that in a certain sense such solutions are analogues of the Nielsen-Olesen tube, since they have a longitudinal magnetic field creating a flux of this field over the central cross-section of the Proca tube. The main difference between the Proca tube and the Nielsen-Olesen tube is that the Proca tube is described by a topologically trivial solution and has finite size, since its energy density decreases exponentially with distance. The dependence of the total field mass of the Proca tube on the value of one of the parameters determining the solution is examined in detail. The solutions are obtained both in the presence and in the absence of external sources (charge and current densities).
[ { "created": "Sat, 24 Jul 2021 08:20:37 GMT", "version": "v1" } ]
2022-01-12
[ [ "Dzhunushaliev", "Vladimir", "" ], [ "Folomeev", "Vladimir", "" ] ]
Within the non-Abelian SU(2) Proca-Higgs theory, we study localised axially symmetric solutions possessing a finite field energy. It is shown that in a certain sense such solutions are analogues of the Nielsen-Olesen tube, since they have a longitudinal magnetic field creating a flux of this field over the central cross-section of the Proca tube. The main difference between the Proca tube and the Nielsen-Olesen tube is that the Proca tube is described by a topologically trivial solution and has finite size, since its energy density decreases exponentially with distance. The dependence of the total field mass of the Proca tube on the value of one of the parameters determining the solution is examined in detail. The solutions are obtained both in the presence and in the absence of external sources (charge and current densities).
hep-ph/9910408
Khalil Shaaban Said
Shaaban Khalil (Autonoma U. de Madrid & Ain Shams U., Cairo)
Non universal gaugino phases and the LSP relic density
10 pages, Latex2e, version to be appeared in Phys. Lett. B
Phys.Lett. B484 (2000) 98-102
10.1016/S0370-2693(00)00598-0
null
hep-ph
null
The cosmological relic density of the lightest supersymmetric particle (LSP) of type I string derived model is calculated. This model can accommodate large values of CP violating phases, and the electron and neutron electric dipole moments satisfy the experimental constraint. We show that the constraint from the electric dipole moment on the ratio between the gaugino masses implies that the mass of the LSP, which is bino like, is close to the lightest chargino. The co-annihilation between them is very important to reduce the LSP relic density to an interesting region. We show that the SUSY phases, although they are large, have no significant effect on the relic density and on the the upper bound imposed on the LSP mass. However, they are very significant for the detection rates. We emphasize that the phase of the trilinear coupling increase the direct and indirect detection rates.
[ { "created": "Tue, 19 Oct 1999 18:50:47 GMT", "version": "v1" }, { "created": "Wed, 17 May 2000 12:08:01 GMT", "version": "v2" } ]
2009-10-31
[ [ "Khalil", "Shaaban", "", "Autonoma U. de Madrid & Ain Shams U., Cairo" ] ]
The cosmological relic density of the lightest supersymmetric particle (LSP) of type I string derived model is calculated. This model can accommodate large values of CP violating phases, and the electron and neutron electric dipole moments satisfy the experimental constraint. We show that the constraint from the electric dipole moment on the ratio between the gaugino masses implies that the mass of the LSP, which is bino like, is close to the lightest chargino. The co-annihilation between them is very important to reduce the LSP relic density to an interesting region. We show that the SUSY phases, although they are large, have no significant effect on the relic density and on the the upper bound imposed on the LSP mass. However, they are very significant for the detection rates. We emphasize that the phase of the trilinear coupling increase the direct and indirect detection rates.
hep-ph/0012281
Cong-Feng Qiao
Cong-Feng Qiao (Hamburg)
QCD Pomeron at Linear Colliders
Contribution to LCWS2000, Fermilab, 24-28 October, 2000, typos in the references corrected
null
10.1063/1.1394346
null
hep-ph
null
Recent developments in theory on the calculation of \gamma^* \gamma^* reaction at high energies, in the aim of detecting the BFKL Pomeron signals, are briefly introduced. The importance of the NLO QCD corrections to the Photon Impact Factor in the game is highlighted.
[ { "created": "Thu, 21 Dec 2000 07:37:07 GMT", "version": "v1" }, { "created": "Sun, 11 Feb 2001 09:26:23 GMT", "version": "v2" } ]
2009-10-31
[ [ "Qiao", "Cong-Feng", "", "Hamburg" ] ]
Recent developments in theory on the calculation of \gamma^* \gamma^* reaction at high energies, in the aim of detecting the BFKL Pomeron signals, are briefly introduced. The importance of the NLO QCD corrections to the Photon Impact Factor in the game is highlighted.
1804.03557
Hannu Paukkunen
Ilkka Helenius and Hannu Paukkunen
Revisiting the D-meson hadroproduction in general-mass variable flavour number scheme
The published version
null
10.1007/JHEP05(2018)196
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We introduce a novel realization of the open heavy-flavour hadroproduction in general-mass variable flavour number scheme at next-to-leading order in perturbative QCD. The principal novelty with respect to the earlier works is in the treatment of small-transverse-momentum limit, which has been a particularly challenging kinematic region in the past. We show that by a suitable choice of scheme, it is possible to obtain a well-behaved description of the open heavy-flavour hadroproduction cross sections from zero up to asymptotically high transverse momentum. We contrast our calculation with the available D$^0$-meson data as measured by the LHCb and ALICE collaborations at the LHC, finding a very good agreement within the theoretical and experimental uncertainties. We also compare our framework with other theoretical approaches.
[ { "created": "Tue, 10 Apr 2018 14:26:03 GMT", "version": "v1" }, { "created": "Wed, 13 Jun 2018 06:42:12 GMT", "version": "v2" } ]
2018-07-04
[ [ "Helenius", "Ilkka", "" ], [ "Paukkunen", "Hannu", "" ] ]
We introduce a novel realization of the open heavy-flavour hadroproduction in general-mass variable flavour number scheme at next-to-leading order in perturbative QCD. The principal novelty with respect to the earlier works is in the treatment of small-transverse-momentum limit, which has been a particularly challenging kinematic region in the past. We show that by a suitable choice of scheme, it is possible to obtain a well-behaved description of the open heavy-flavour hadroproduction cross sections from zero up to asymptotically high transverse momentum. We contrast our calculation with the available D$^0$-meson data as measured by the LHCb and ALICE collaborations at the LHC, finding a very good agreement within the theoretical and experimental uncertainties. We also compare our framework with other theoretical approaches.
1807.04758
Gavin Salam
Frederic A. Dreyer, Gavin P. Salam and Gregory Soyez
The Lund Jet Plane
42 pages, 20 figures; v2 adds discussion of $k_t$ and anti-$k_t$ declustering and corrects statements about relations with other observables
null
10.1007/JHEP12(2018)064
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Lund diagrams, a theoretical representation of the phase space within jets, have long been used in discussing parton showers and resummations. We point out that they can be created for individual jets through repeated Cambridge/Aachen declustering, providing a powerful visual representation of the radiation within any given jet. Concentrating here on the primary Lund plane, we outline some of its analytical properties, highlight its scope for constraining Monte Carlo simulations and comment on its relation with existing observables such as the $z_g$ variable and the iterated soft-drop multiplicity. We then examine its use for boosted electroweak boson tagging at high momenta. It provides good performance when used as an input to machine learning. Much of this performance can be reproduced also within a transparent log-likelihood method, whose underlying assumption is that different regions of the primary Lund plane are largely decorrelated. This suggests a potential for unique insight and experimental validation of the features being used by machine-learning approaches.
[ { "created": "Thu, 12 Jul 2018 18:00:03 GMT", "version": "v1" }, { "created": "Tue, 30 Oct 2018 15:02:16 GMT", "version": "v2" } ]
2018-12-26
[ [ "Dreyer", "Frederic A.", "" ], [ "Salam", "Gavin P.", "" ], [ "Soyez", "Gregory", "" ] ]
Lund diagrams, a theoretical representation of the phase space within jets, have long been used in discussing parton showers and resummations. We point out that they can be created for individual jets through repeated Cambridge/Aachen declustering, providing a powerful visual representation of the radiation within any given jet. Concentrating here on the primary Lund plane, we outline some of its analytical properties, highlight its scope for constraining Monte Carlo simulations and comment on its relation with existing observables such as the $z_g$ variable and the iterated soft-drop multiplicity. We then examine its use for boosted electroweak boson tagging at high momenta. It provides good performance when used as an input to machine learning. Much of this performance can be reproduced also within a transparent log-likelihood method, whose underlying assumption is that different regions of the primary Lund plane are largely decorrelated. This suggests a potential for unique insight and experimental validation of the features being used by machine-learning approaches.
hep-ph/0601166
Hendrik van Hees
H. van Hees, V. Greco, R. Rapp
Thermalization and Flow of Heavy Quarks in the Quark-Gluon Plasma
proceedings for PANIC05
AIP Conf. Proc. 842, 77 (2006)
10.1063/1.2220193
null
hep-ph nucl-ex nucl-th
null
Elastic scattering of charm (c) and bottom (b) quarks via D- and B-meson resonance states in an expanding, strongly interacting quark-gluon plasma is investigated. Drag and diffusion coefficients are calculated from an effective model based on chiral symmetry and heavy-quark effective theory, and utilized in a relativistic Langevin simulation to obtain transverse-momentum spectra and elliptic flow (v_2) of c- and b-quarks. The hadronization to D- and B-mesons is described by coalescence and fragmentation, and the resulting decay-electron spectra are compared to recent RHIC data.
[ { "created": "Fri, 20 Jan 2006 00:08:38 GMT", "version": "v1" } ]
2007-05-23
[ [ "van Hees", "H.", "" ], [ "Greco", "V.", "" ], [ "Rapp", "R.", "" ] ]
Elastic scattering of charm (c) and bottom (b) quarks via D- and B-meson resonance states in an expanding, strongly interacting quark-gluon plasma is investigated. Drag and diffusion coefficients are calculated from an effective model based on chiral symmetry and heavy-quark effective theory, and utilized in a relativistic Langevin simulation to obtain transverse-momentum spectra and elliptic flow (v_2) of c- and b-quarks. The hadronization to D- and B-mesons is described by coalescence and fragmentation, and the resulting decay-electron spectra are compared to recent RHIC data.
hep-ph/9609415
null
S. J. Brodsky
Novel QCD Effects in the Production and Decay of Quarkonium
Latex, 12 pages
Int.J.Mod.Phys.A12:4087-4098,1997
10.1142/S0217751X97002243
SLAC-PUB-7306
hep-ph
null
There are many outstanding discrepancies comparing the predictions of perturbative QCD and measurements of the rate of production and decay of heavy quark systems. The problems include the $J/\psi \to \rho \pi$ puzzle, leading charmed particle effects, the anomalous behavior of the heavy quark sea components of structure functions, anomalous nuclear target effects, and the large rates observed for single and double quarkonium production at large $x_F$ and large $p_T$. I argue that these anomalies may be associated with nonperturbative effects in the higher Fock structure of hadron wavefunctions.
[ { "created": "Thu, 19 Sep 1996 22:29:44 GMT", "version": "v1" } ]
2009-09-11
[ [ "Brodsky", "S. J.", "" ] ]
There are many outstanding discrepancies comparing the predictions of perturbative QCD and measurements of the rate of production and decay of heavy quark systems. The problems include the $J/\psi \to \rho \pi$ puzzle, leading charmed particle effects, the anomalous behavior of the heavy quark sea components of structure functions, anomalous nuclear target effects, and the large rates observed for single and double quarkonium production at large $x_F$ and large $p_T$. I argue that these anomalies may be associated with nonperturbative effects in the higher Fock structure of hadron wavefunctions.
0706.3980
Boris Kerbikov
B.O.Kerbikov
Fluctuation Propagator and Heavy Quark Diffusion
Contribution to the proceedings of the Rencontres de Moriond on QCD and Hadronic Interactions, La Thuile, Italy, March 2007
null
null
null
hep-ph
null
The quark fluctuation propagator is evaluated. It defines the diffusion coefficient in the vicinity of the phase transition and the gradient term in the Ginzburg-Landau functional.
[ { "created": "Wed, 27 Jun 2007 08:33:27 GMT", "version": "v1" } ]
2007-06-28
[ [ "Kerbikov", "B. O.", "" ] ]
The quark fluctuation propagator is evaluated. It defines the diffusion coefficient in the vicinity of the phase transition and the gradient term in the Ginzburg-Landau functional.
0910.3403
Xin-Nian Wang
Wei-tian Deng (Shandong U. and LBNL) and Xin-Nian Wang (LBNL)
Multiple Parton Scattering in Nuclei: Modified DGLAP Evolution for Fragmentation Functions
21 pages in RevTex with 19 figures (some contents are added in this version)
Phys.Rev.C81:024902,2010
10.1103/PhysRevC.81.024902
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Within the framework of generalized factorization of higher-twist contributions to semi-inclusive cross section of deeply inelastic scattering off a large nucleus, multiple parton scattering leads to an effective medium-modified fragmentation function and the corresponding medium-modified DGLAP evolution equations. We extend the study to include gluon multiple scattering and induced quark-antiquark production via gluon fusion . We numerically solve these medium-modified DGLAP (mDGLAP) evolution equations and study the scale ($Q^2$), energy ($E$), length ($L$) and jet transport parameter ($\hat q$) dependence of the modified fragmentation functions for a jet propagating in a uniform medium with finite length (a "brick" problem). We also discuss the concept of parton energy loss within such mDGLAP evolution equations and its connection to the modified fragmentation functions. With a realistic Wood-Saxon nuclear geometry, we calculate the modified fragmentation functions and compare to experimental data of DIS off large nuclei. The extracted jet transport parameter at the center of a large nucleus is found to be $\hat q_{0}=0.024\pm0.008$ GeV$^{2}$/fm.
[ { "created": "Sun, 18 Oct 2009 19:26:06 GMT", "version": "v1" }, { "created": "Tue, 20 Oct 2009 03:13:13 GMT", "version": "v2" }, { "created": "Thu, 4 Mar 2010 07:07:54 GMT", "version": "v3" } ]
2014-11-20
[ [ "Deng", "Wei-tian", "", "Shandong U. and LBNL" ], [ "Wang", "Xin-Nian", "", "LBNL" ] ]
Within the framework of generalized factorization of higher-twist contributions to semi-inclusive cross section of deeply inelastic scattering off a large nucleus, multiple parton scattering leads to an effective medium-modified fragmentation function and the corresponding medium-modified DGLAP evolution equations. We extend the study to include gluon multiple scattering and induced quark-antiquark production via gluon fusion . We numerically solve these medium-modified DGLAP (mDGLAP) evolution equations and study the scale ($Q^2$), energy ($E$), length ($L$) and jet transport parameter ($\hat q$) dependence of the modified fragmentation functions for a jet propagating in a uniform medium with finite length (a "brick" problem). We also discuss the concept of parton energy loss within such mDGLAP evolution equations and its connection to the modified fragmentation functions. With a realistic Wood-Saxon nuclear geometry, we calculate the modified fragmentation functions and compare to experimental data of DIS off large nuclei. The extracted jet transport parameter at the center of a large nucleus is found to be $\hat q_{0}=0.024\pm0.008$ GeV$^{2}$/fm.
hep-ph/0311052
Michele Caffo
Michele Caffo (INFN and Univ., Bologna)
Numerical evaluation of some master integrals for the 2-loop general massive self-mass from differential equations
Latex, 8 pag., 3 fig., uses appolb.cls, Presented at Matter To The Deepest, XXVII ICTP, Ustron (Poland), 15-21 Sept 2003
Acta Phys.Polon. B34 (2003) 5357-5364
null
null
hep-ph
null
The 4-th order Runge-Kutta method in the complex plane is proposed for numerically advancing the solutions of a system of first order differential equations in one external invariant satisfied by the master integrals related to a Feynman graph. Some results obtained for the 2-loop self-mass MI are reviewed. The method offers a reliable and robust approach to the direct and precise numerical evaluation of master integrals.
[ { "created": "Tue, 4 Nov 2003 17:38:31 GMT", "version": "v1" } ]
2007-05-23
[ [ "Caffo", "Michele", "", "INFN and Univ., Bologna" ] ]
The 4-th order Runge-Kutta method in the complex plane is proposed for numerically advancing the solutions of a system of first order differential equations in one external invariant satisfied by the master integrals related to a Feynman graph. Some results obtained for the 2-loop self-mass MI are reviewed. The method offers a reliable and robust approach to the direct and precise numerical evaluation of master integrals.
hep-ph/9505204
null
J. L. Goity and M. J. Musolf
A STRANGE MESONIC TRANSITION FORM FACTOR
Revtex, six figures available as hard copy upon request.
Phys.Rev.C53:399-409,1996
10.1103/PhysRevC.53.399
CEBAF-TH-94-27
hep-ph
null
The strange-quark vector current $\rho$-to-$\pi$ meson transition form factor is computed at one-loop order using strange meson intermediate states. A comparison is made with a $\phi$-meson dominance model estimate. We find that one-loop contributions are comparable in magnitude to those predicted by $\phi$-meson dominance. It is possible that the one-loop contribution can make the matrix element as large as those of the electromagnetic current mediating vector meson radiative decays. However, due to the quadratic dependence of the one-loop results on the hadronic form factor cut-off mass, a large uncertainty in the estimate of the loops is unavoidable. These results indicate that non-nucleonic strange quarks could contribute appreciably in moderate-$|Q^2|$ parity-violating electron-nucleus scattering measurements aimed at probing the strange-quark content of the nucleon.
[ { "created": "Mon, 1 May 1995 20:42:00 GMT", "version": "v1" } ]
2008-11-26
[ [ "Goity", "J. L.", "" ], [ "Musolf", "M. J.", "" ] ]
The strange-quark vector current $\rho$-to-$\pi$ meson transition form factor is computed at one-loop order using strange meson intermediate states. A comparison is made with a $\phi$-meson dominance model estimate. We find that one-loop contributions are comparable in magnitude to those predicted by $\phi$-meson dominance. It is possible that the one-loop contribution can make the matrix element as large as those of the electromagnetic current mediating vector meson radiative decays. However, due to the quadratic dependence of the one-loop results on the hadronic form factor cut-off mass, a large uncertainty in the estimate of the loops is unavoidable. These results indicate that non-nucleonic strange quarks could contribute appreciably in moderate-$|Q^2|$ parity-violating electron-nucleus scattering measurements aimed at probing the strange-quark content of the nucleon.
hep-ph/9801333
Stephane Bronoff groupe
S. Bronoff, R. Buffa, C.P. Korthals Altes
Thermal Gauge Theory, Effective Action and Z(N) Symmetry
10 pages including figures, LaTeX, uses epsfig and sprocl2
null
null
null
hep-ph
null
One of the salient features of high temperature gluodynamics is the Z(N) groundstate degeneracy, key to the understanding of the transition. On the other hand impressive progress has been obtained with effective theories, that seemingly lack Z(N) symmetry. We give a simple unified desciption of the two. As a very useful byproduct we get a natural infrared regulator and show its expediency by calculating the next to leading order in the Debye mass. Higher order corrections to bulk free energy and domainwall surface tension are discussed.
[ { "created": "Sat, 17 Jan 1998 14:53:45 GMT", "version": "v1" } ]
2007-05-23
[ [ "Bronoff", "S.", "" ], [ "Buffa", "R.", "" ], [ "Altes", "C. P. Korthals", "" ] ]
One of the salient features of high temperature gluodynamics is the Z(N) groundstate degeneracy, key to the understanding of the transition. On the other hand impressive progress has been obtained with effective theories, that seemingly lack Z(N) symmetry. We give a simple unified desciption of the two. As a very useful byproduct we get a natural infrared regulator and show its expediency by calculating the next to leading order in the Debye mass. Higher order corrections to bulk free energy and domainwall surface tension are discussed.
1012.0564
Marc Vanderhaeghen
Julia Guttmann, Nikolai Kivel, Mehdi Meziane, Marc Vanderhaeghen
Determination of two-photon exchange amplitudes from elastic electron-proton scattering data
4 pages, 5 figures, updated error analysis
null
10.1140/epja/i2011-11077-4
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Using the available cross section and polarization data for elastic electron-proton scattering, we provide an extraction of the two-photon exchange amplitudes at a common value of four-momentum transfer, around Q^2 = 2.5 GeV^2. This analysis also predicts the e^+ p / e^- p elastic scattering cross section ratio, which will be measured by forthcoming experiments.
[ { "created": "Thu, 2 Dec 2010 20:51:12 GMT", "version": "v1" }, { "created": "Sun, 27 Feb 2011 21:46:24 GMT", "version": "v2" } ]
2015-05-20
[ [ "Guttmann", "Julia", "" ], [ "Kivel", "Nikolai", "" ], [ "Meziane", "Mehdi", "" ], [ "Vanderhaeghen", "Marc", "" ] ]
Using the available cross section and polarization data for elastic electron-proton scattering, we provide an extraction of the two-photon exchange amplitudes at a common value of four-momentum transfer, around Q^2 = 2.5 GeV^2. This analysis also predicts the e^+ p / e^- p elastic scattering cross section ratio, which will be measured by forthcoming experiments.
1802.02171
Martin Jung
Timo Fleig and Martin Jung
Model-independent determinations of the electron EDM and the role of diamagnetic atoms
15+5 pages, 6 tables, 1 figure
null
10.1007/JHEP07(2018)012
null
hep-ph physics.atom-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We perform model-independent analyses extracting limits for the electric dipole moment of the electron and the P,T-odd scalar-pseudoscalar (S-PS) nucleon-electron coupling from the most recent measurements with atoms and molecules. The analysis using paramagnetic systems, only, is improved substantially by the inclusion of the recent measurement on HfF+ ions, but complicated by the fact that the corresponding constraints are largely aligned, owing to a general relation between the coefficients for the two contributions. Since this same relation does not hold in diamagnetic systems, it is possible to find atoms that provide essentially orthogonal constraints to those from para\-magnetic ones. However, the coefficients are suppressed in closed-shell systems and enhancements of P,T-odd effects are only prevalent in the presence of hyperfine interactions. We formulate the hyperfine-induced time-reversal-symmetry breaking S-PS nucleon-electron interaction in general atoms in a mixed perturbative and variational approach, based on electronic Dirac-wavefunctions including the effects of electron correlations. The method is applied to the Hg atom, yielding the first direct calculation of the coefficient of the S-PS nucleon-electron coupling in a diamagnetic system. This results in additionally improved model-independent limits for both the electron EDM and the nucleon-electron coupling from the global fit. Finally we employ this fit to provide indirect limits for several paramagnetic systems under investigation.
[ { "created": "Tue, 6 Feb 2018 19:04:40 GMT", "version": "v1" } ]
2018-08-01
[ [ "Fleig", "Timo", "" ], [ "Jung", "Martin", "" ] ]
We perform model-independent analyses extracting limits for the electric dipole moment of the electron and the P,T-odd scalar-pseudoscalar (S-PS) nucleon-electron coupling from the most recent measurements with atoms and molecules. The analysis using paramagnetic systems, only, is improved substantially by the inclusion of the recent measurement on HfF+ ions, but complicated by the fact that the corresponding constraints are largely aligned, owing to a general relation between the coefficients for the two contributions. Since this same relation does not hold in diamagnetic systems, it is possible to find atoms that provide essentially orthogonal constraints to those from para\-magnetic ones. However, the coefficients are suppressed in closed-shell systems and enhancements of P,T-odd effects are only prevalent in the presence of hyperfine interactions. We formulate the hyperfine-induced time-reversal-symmetry breaking S-PS nucleon-electron interaction in general atoms in a mixed perturbative and variational approach, based on electronic Dirac-wavefunctions including the effects of electron correlations. The method is applied to the Hg atom, yielding the first direct calculation of the coefficient of the S-PS nucleon-electron coupling in a diamagnetic system. This results in additionally improved model-independent limits for both the electron EDM and the nucleon-electron coupling from the global fit. Finally we employ this fit to provide indirect limits for several paramagnetic systems under investigation.
hep-ph/0402011
Mikhail Voloshin
M.B. Voloshin
Quarkonium chromo-polarizability from the decays $J/\psi(\Upsilon) \to \pi \pi \ell^+ \ell^-$
6 pages
Mod.Phys.Lett. A19 (2004) 665-670
10.1142/S0217732304013568
FTPI-MINN-04/05, UMN-TH-2232-04
hep-ph
null
It is pointed out that the diagonal amplitude of the $E1-E1$ chromo-electric interaction with soft gluon fields (chromo-polarizability) can be measured directly for the $J/\psi$ and $\Upsilon$ resonances in the decays $J/\psi \to \pi \pi \ell^+ \ell^-$ and $\Upsilon \to \pi \pi \ell^+ \ell^-$ with soft pions. For the $J/\psi$ this amplitude is often discussed in connection with the $J/\psi$ interaction with nuclear matter, while for the $\Upsilon$ the chromo-polarizability enters the estimates of the non-perturbative mass shift of the resonance relevant to precision determination of the $b$ quark mass from the $\Upsilon$ mass.
[ { "created": "Mon, 2 Feb 2004 16:43:57 GMT", "version": "v1" } ]
2009-11-10
[ [ "Voloshin", "M. B.", "" ] ]
It is pointed out that the diagonal amplitude of the $E1-E1$ chromo-electric interaction with soft gluon fields (chromo-polarizability) can be measured directly for the $J/\psi$ and $\Upsilon$ resonances in the decays $J/\psi \to \pi \pi \ell^+ \ell^-$ and $\Upsilon \to \pi \pi \ell^+ \ell^-$ with soft pions. For the $J/\psi$ this amplitude is often discussed in connection with the $J/\psi$ interaction with nuclear matter, while for the $\Upsilon$ the chromo-polarizability enters the estimates of the non-perturbative mass shift of the resonance relevant to precision determination of the $b$ quark mass from the $\Upsilon$ mass.
1801.01513
Kirtiman Ghosh
Debajyoti Choudhury, Kirtiman Ghosh and Saurabh Niyogi
Non-Standard Neutrino Interactions : Obviating Oscillation Experiments
5 pages, 2 figures
Phys.Lett.B 784 (2018) 248-254
10.1016/j.physletb.2018.07.053
IP/BBSR/2017-17
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Searching for non-standard neutrino interactions, as a means for discovering physics beyond the Standard Model, has one of the key goals of dedicated neutrino experiments, current and future. We demonstrate here that much of the parameter space accessible to such experiments is already ruled out by the RUN II data of the Large Hadron Collider experiment.
[ { "created": "Thu, 4 Jan 2018 19:05:45 GMT", "version": "v1" } ]
2020-07-06
[ [ "Choudhury", "Debajyoti", "" ], [ "Ghosh", "Kirtiman", "" ], [ "Niyogi", "Saurabh", "" ] ]
Searching for non-standard neutrino interactions, as a means for discovering physics beyond the Standard Model, has one of the key goals of dedicated neutrino experiments, current and future. We demonstrate here that much of the parameter space accessible to such experiments is already ruled out by the RUN II data of the Large Hadron Collider experiment.
2103.05688
Katsuya Hashino
Qing-Hong Cao, Katsuya Hashino, Xu-Xiang Li, Zhe Ren and Jiang-Hao Yu
Electroweak phase transition triggered by fermion sector
26 pages, 9 figures
null
10.1007/JHEP01(2022)001
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
To realize first-order electroweak phase transition, it is necessary to generate a barrier in the thermal Higgs potential, which is usually triggered by scalar degree of freedom. We instead investigate phase transition patterns in pure fermion extensions of the standard model, and find that additional fermions with mass hierarchy and mixing could develop such barrier and realize strongly first-order phase transition in such models. In the Higgs potential with polynomial parametrization, the barrier can be generated in the following two patterns: (I) positive quadratic term, negative cubic term and positive quartic term or (II) positive quadratic term, negative quartic term and positive higher dimensional term, such as dimensional 6 operator.
[ { "created": "Tue, 9 Mar 2021 19:46:59 GMT", "version": "v1" } ]
2022-01-19
[ [ "Cao", "Qing-Hong", "" ], [ "Hashino", "Katsuya", "" ], [ "Li", "Xu-Xiang", "" ], [ "Ren", "Zhe", "" ], [ "Yu", "Jiang-Hao", "" ] ]
To realize first-order electroweak phase transition, it is necessary to generate a barrier in the thermal Higgs potential, which is usually triggered by scalar degree of freedom. We instead investigate phase transition patterns in pure fermion extensions of the standard model, and find that additional fermions with mass hierarchy and mixing could develop such barrier and realize strongly first-order phase transition in such models. In the Higgs potential with polynomial parametrization, the barrier can be generated in the following two patterns: (I) positive quadratic term, negative cubic term and positive quartic term or (II) positive quadratic term, negative quartic term and positive higher dimensional term, such as dimensional 6 operator.
hep-ph/0303069
Harry Chi-Sing Lam
D. Charuchittipan and C.S. Lam
The Absorptive Extra Dimensions
Introduction enlarged; conclusions added. To appear in Phys. Rev. D
Phys.Rev. D68 (2003) 033016
10.1103/PhysRevD.68.033016
null
hep-ph
null
It is well known that gravity and neutrino oscillation can be used to probe large extra dimensions in a braneworld scenario. We argue that neutrino oscillation remains a useful probe even when the extra dimensions are small, because the brane-bulk coupling is likely to be large. Neutrino oscillation in the presence of a strong brane-bulk coupling is vastly different from the usual case of a weak coupling. In particular, some active neutrinos could be absorbed by the bulk when they oscillate from one kind to another, a signature which can be taken as the presence of an extra dimension. In a very large class of models which we shall discuss, the amount of absorption for all neutrino oscillations is controlled by a single parameter, a property which distinguishes extra dimensions from other mechanisms for losing neutrino fluxes.
[ { "created": "Sun, 9 Mar 2003 14:55:39 GMT", "version": "v1" }, { "created": "Mon, 26 May 2003 17:25:08 GMT", "version": "v2" } ]
2009-11-10
[ [ "Charuchittipan", "D.", "" ], [ "Lam", "C. S.", "" ] ]
It is well known that gravity and neutrino oscillation can be used to probe large extra dimensions in a braneworld scenario. We argue that neutrino oscillation remains a useful probe even when the extra dimensions are small, because the brane-bulk coupling is likely to be large. Neutrino oscillation in the presence of a strong brane-bulk coupling is vastly different from the usual case of a weak coupling. In particular, some active neutrinos could be absorbed by the bulk when they oscillate from one kind to another, a signature which can be taken as the presence of an extra dimension. In a very large class of models which we shall discuss, the amount of absorption for all neutrino oscillations is controlled by a single parameter, a property which distinguishes extra dimensions from other mechanisms for losing neutrino fluxes.
1802.05855
Walaa I. Eshraim
Walaa I. Eshraim and Christian S. Fischer
Hadronic decays of the (pseudo-)scalar charmonium states $\eta_c$ and $\chi_{c0}$ in the extended Linear Sigma Model
20 pages, 3 figures, 6 tabes
Eur. Phys. J. A 54 (2018) no.8, 139
10.1140/epja/i2018-12569-3
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the phenomenology of the ground-state (pseudo-)scalar charmonia $\eta_c$ and $\chi_{c0}$ in the framework of a $U(4)_r \times U(4)_l$ symmetric linear sigma model with (pseudo-)scalar and (axial-) vector mesons. Based on previous results for the spectrum of charmonia and the spectrum and (OZI-dominant) strong decays of open charmed mesons, we extend the study of this model to OZI-suppressed charmonia decays. This includes decays into 'ordinary' mesons but also particularly interesting channels with scalar-isoscalar resonances $f_0(1370),\, f_0(1500),\, f_0(1710)$ that may include sizeable contributions from a scalar glueball. We study the variation of the corresponding decay widths assuming different mixings between glueball and quark-antiquark states. We also compute the decay width of the pseudoscalar $\eta_c$ into a pseudoscalar glueball. In general, our results for decay widths are in reasonable agreement with experimental data where available. Order of magnitude predictions for as yet unmeasured states and channels are potentially interesting for BESIII, Belle II, LHCb as well as the future PANDA experiment at the FAIR facility.
[ { "created": "Fri, 16 Feb 2018 07:51:13 GMT", "version": "v1" }, { "created": "Mon, 27 Aug 2018 19:20:54 GMT", "version": "v2" } ]
2018-08-29
[ [ "Eshraim", "Walaa I.", "" ], [ "Fischer", "Christian S.", "" ] ]
We study the phenomenology of the ground-state (pseudo-)scalar charmonia $\eta_c$ and $\chi_{c0}$ in the framework of a $U(4)_r \times U(4)_l$ symmetric linear sigma model with (pseudo-)scalar and (axial-) vector mesons. Based on previous results for the spectrum of charmonia and the spectrum and (OZI-dominant) strong decays of open charmed mesons, we extend the study of this model to OZI-suppressed charmonia decays. This includes decays into 'ordinary' mesons but also particularly interesting channels with scalar-isoscalar resonances $f_0(1370),\, f_0(1500),\, f_0(1710)$ that may include sizeable contributions from a scalar glueball. We study the variation of the corresponding decay widths assuming different mixings between glueball and quark-antiquark states. We also compute the decay width of the pseudoscalar $\eta_c$ into a pseudoscalar glueball. In general, our results for decay widths are in reasonable agreement with experimental data where available. Order of magnitude predictions for as yet unmeasured states and channels are potentially interesting for BESIII, Belle II, LHCb as well as the future PANDA experiment at the FAIR facility.
1404.3676
Kamakshya Modak
Kamakshya Prasad Modak
3.5 keV X-ray Line Signal from Decay of Right-Handed Neutrino due to Transition Magnetic Moment
11 Pages LaTeX, 2 Figures, 1 Table
null
10.1007/JHEP03(2015)064
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider the dark matter model with radiative neutrino mass generation where the Standard Model is extended with three right-handed singlet neutrinos ($N_1$, $N_2$ and $N_3$) and one additional SU(2)$_L$ doublet scalar $\eta$. One of the right-handed neutrinos ($N_1$), being lightest among them, is a leptophilic fermionic dark matter candidate whose stability is ensured by the imposed $\mathbb{Z}_2$ symmetry on this model. The second lightest right-handed neutrino ($N_2$) is assumed to be nearly degenerated with the lightest one enhancing the co-annihilation between them. The effective interaction term among the lightest, second lightest right-handed neutrinos and photon containing transition magnetic moment is responsible for the decay of heavier right-handed neutrino to the lightest one and a photon ($N_2\to N_1 + \gamma$). This radiative decay of heavier right-handed neutrino %to the the lightest one with charged scalar and leptons in internal lines could explain the X-ray line signal $\sim$ $3.5$ keV recently claimed by XMM-Newton X-ray observatory from different galaxy clusters and Andromeda galaxy (M31). The value of the transition magnetic moment is computed and found to be several orders of magnitude below the current reach of various direct dark matter searches. The other parameter space in this framework in the light of the observed signal is further investigated.
[ { "created": "Mon, 14 Apr 2014 18:13:54 GMT", "version": "v1" } ]
2018-01-17
[ [ "Modak", "Kamakshya Prasad", "" ] ]
We consider the dark matter model with radiative neutrino mass generation where the Standard Model is extended with three right-handed singlet neutrinos ($N_1$, $N_2$ and $N_3$) and one additional SU(2)$_L$ doublet scalar $\eta$. One of the right-handed neutrinos ($N_1$), being lightest among them, is a leptophilic fermionic dark matter candidate whose stability is ensured by the imposed $\mathbb{Z}_2$ symmetry on this model. The second lightest right-handed neutrino ($N_2$) is assumed to be nearly degenerated with the lightest one enhancing the co-annihilation between them. The effective interaction term among the lightest, second lightest right-handed neutrinos and photon containing transition magnetic moment is responsible for the decay of heavier right-handed neutrino to the lightest one and a photon ($N_2\to N_1 + \gamma$). This radiative decay of heavier right-handed neutrino %to the the lightest one with charged scalar and leptons in internal lines could explain the X-ray line signal $\sim$ $3.5$ keV recently claimed by XMM-Newton X-ray observatory from different galaxy clusters and Andromeda galaxy (M31). The value of the transition magnetic moment is computed and found to be several orders of magnitude below the current reach of various direct dark matter searches. The other parameter space in this framework in the light of the observed signal is further investigated.
1602.03548
Sergei Gninenko
S.N. Gninenko and N.V. Krasnikov
Invisible $K_L$ decays in the SM extensions
11 pages, no figures
Mod. Phys. Lett. A, Vol. 31, No. 25 (2016) 1650142
10.1142/S021773231650142X
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In the Standard Model (SM) the branching ratio for the decay $K_L \to \nu \bar{\nu}$ into two neutrinos is helicity suppressed and predicted to be very small $ \leq O(10^{-17})$. We consider two natural extensions of the SM, such as two-Higgs-doublet model (2HDM) and the $\nu$MSM with additional singlet scalar, those main features is that they can lead to an enhanced $Br(K_L \to invisible)$. In the 2HDM the smallness of the neutrino mass is explained due to the smallness of the second Higgs doublet vacuum expectation value. Moreover, the $\nu$MSM extension with additional singlet field can explain the $(g - 2)$ muon anomaly. The considered models demonstrate that the $K_L \to invisible $ decay is a clean probe of new physics scales well above 100 TeV, that is complementary to rare $K \to \pi+invisible$ decay, and provide a strong motivation for its sensitive search in a near future low-energy experiment.
[ { "created": "Wed, 10 Feb 2016 21:59:22 GMT", "version": "v1" } ]
2016-07-29
[ [ "Gninenko", "S. N.", "" ], [ "Krasnikov", "N. V.", "" ] ]
In the Standard Model (SM) the branching ratio for the decay $K_L \to \nu \bar{\nu}$ into two neutrinos is helicity suppressed and predicted to be very small $ \leq O(10^{-17})$. We consider two natural extensions of the SM, such as two-Higgs-doublet model (2HDM) and the $\nu$MSM with additional singlet scalar, those main features is that they can lead to an enhanced $Br(K_L \to invisible)$. In the 2HDM the smallness of the neutrino mass is explained due to the smallness of the second Higgs doublet vacuum expectation value. Moreover, the $\nu$MSM extension with additional singlet field can explain the $(g - 2)$ muon anomaly. The considered models demonstrate that the $K_L \to invisible $ decay is a clean probe of new physics scales well above 100 TeV, that is complementary to rare $K \to \pi+invisible$ decay, and provide a strong motivation for its sensitive search in a near future low-energy experiment.
hep-ph/0212119
D. Ghilencea
D. M. Ghilencea
On Gauge couplings, "Large" extra-dimensions and the limit alpha'->0 of the String
18 pages; Latex
Nucl.Phys. B653 (2003) 27-44
10.1016/S0550-3213(03)00054-3
DAMTP-2002-140
hep-ph hep-th
null
Using an effective field theory (EFT) approach for a generic model with two additional dimensions compactified on a two-torus, we compute the total one-loop radiative corrections to the gauge couplings due to associated Kaluza-Klein massive and massless states. A consistent treatment of both infrared (IR) and ultraviolet (UV) divergences shows a connection via infrared regulator effects between the massless and massive sectors of a compactified theory. A new correction to the gauge couplings is found such that their UV behaviour is sensitive to IR regulator dependent effects in the sector of (infinitely many) massive modes. This correction is a one-loop UV-IR mixing effect due to infinitely many Kaluza-Klein modes and exists for two compact dimensions. The link with string theory is addressed to show that this correction, logarithmic in the UV scale, cannot be recovered from known (infrared regularised) string calculations in the field theory ``limit'' alpha'->0. We explain the origin of this discrepancy and address some of its implications.
[ { "created": "Mon, 9 Dec 2002 14:38:58 GMT", "version": "v1" }, { "created": "Tue, 10 Dec 2002 21:29:45 GMT", "version": "v2" }, { "created": "Mon, 4 Aug 2003 11:35:17 GMT", "version": "v3" }, { "created": "Fri, 22 Aug 2003 12:48:34 GMT", "version": "v4" } ]
2010-04-05
[ [ "Ghilencea", "D. M.", "" ] ]
Using an effective field theory (EFT) approach for a generic model with two additional dimensions compactified on a two-torus, we compute the total one-loop radiative corrections to the gauge couplings due to associated Kaluza-Klein massive and massless states. A consistent treatment of both infrared (IR) and ultraviolet (UV) divergences shows a connection via infrared regulator effects between the massless and massive sectors of a compactified theory. A new correction to the gauge couplings is found such that their UV behaviour is sensitive to IR regulator dependent effects in the sector of (infinitely many) massive modes. This correction is a one-loop UV-IR mixing effect due to infinitely many Kaluza-Klein modes and exists for two compact dimensions. The link with string theory is addressed to show that this correction, logarithmic in the UV scale, cannot be recovered from known (infrared regularised) string calculations in the field theory ``limit'' alpha'->0. We explain the origin of this discrepancy and address some of its implications.
hep-ph/0607002
Keith Olive
John Ellis, Keith A. Olive, and Pearl Sandick
What if supersymmetry breaking appears below the GUT scale?
21 pages, 14 figures
Phys.Lett.B642:389-399,2006
10.1016/j.physletb.2006.09.043
CERN-PH-TH/2006-110, UMN-TH-2509/06, FTPI-MINN-06/23
hep-ph
null
We consider the possibility that the soft supersymmetry-breaking parameters m_{1/2} and m_0 of the MSSM are universal at some scale M_{in} below the supersymmetric grand unification scale M_{GUT}, as might occur in scenarios where either the primordial supersymmetry-breaking mechanism or its communication to the observable sector involve a dynamical scale below M_{GUT}. We analyze the (m_{1/2}, m_0) planes of such sub-GUT CMSSM models, noting the dependences of phenomenological, experimental and cosmological constraints on M_{in}. In particular, we find that the coannihilation, focus-point and rapid-annihilation funnel regions of the GUT-scale CMSSM approach and merge when M_{in} \sim 10^{12} GeV. We discuss sparticle spectra and the possible sensitivity of LHC measurements to the value of M_{in}.
[ { "created": "Fri, 30 Jun 2006 20:05:13 GMT", "version": "v1" } ]
2008-11-26
[ [ "Ellis", "John", "" ], [ "Olive", "Keith A.", "" ], [ "Sandick", "Pearl", "" ] ]
We consider the possibility that the soft supersymmetry-breaking parameters m_{1/2} and m_0 of the MSSM are universal at some scale M_{in} below the supersymmetric grand unification scale M_{GUT}, as might occur in scenarios where either the primordial supersymmetry-breaking mechanism or its communication to the observable sector involve a dynamical scale below M_{GUT}. We analyze the (m_{1/2}, m_0) planes of such sub-GUT CMSSM models, noting the dependences of phenomenological, experimental and cosmological constraints on M_{in}. In particular, we find that the coannihilation, focus-point and rapid-annihilation funnel regions of the GUT-scale CMSSM approach and merge when M_{in} \sim 10^{12} GeV. We discuss sparticle spectra and the possible sensitivity of LHC measurements to the value of M_{in}.
1608.00791
J. Armando Arroyo
J. Armando Arroyo, Saul Ramos-Sanchez
One-loop corrections for Higgs-portal dark matter
6 pages, 4 figures, To be published in Journal of Physics Conference Series (IOP). Joint Proceedings of the XV Mexican Workshop on Particles and Fields & the XXX Annual Meeting of the Division of Particles and Fields of the Mexican Physical Society
null
10.1088/1742-6596/761/1/012014
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Models endowed with Higgs portals can probe into the hidden sectors of particle physics while providing stable dark matter candidates. Previous tree-level computations in such scenarios have shown that experimental bounds constrain dark matter to a very narrow region in parameter space. Aiming at improving the study of the implications of those constraints, we inspect one-loop corrections to the annihilation cross section for scalar dark matter into observable fermions. We find that these loop contributions might be enough to drastically change those results by deforming in about 10% the allowed parameter space for dark matter particles with masses even below 1 TeV. These findings encourage further investigation.
[ { "created": "Tue, 2 Aug 2016 12:34:28 GMT", "version": "v1" } ]
2016-11-23
[ [ "Arroyo", "J. Armando", "" ], [ "Ramos-Sanchez", "Saul", "" ] ]
Models endowed with Higgs portals can probe into the hidden sectors of particle physics while providing stable dark matter candidates. Previous tree-level computations in such scenarios have shown that experimental bounds constrain dark matter to a very narrow region in parameter space. Aiming at improving the study of the implications of those constraints, we inspect one-loop corrections to the annihilation cross section for scalar dark matter into observable fermions. We find that these loop contributions might be enough to drastically change those results by deforming in about 10% the allowed parameter space for dark matter particles with masses even below 1 TeV. These findings encourage further investigation.
1812.03060
Xiaoran Zhao
Manoj K. Mandal, Xiaoran Zhao
Evaluating multi-loop Feynman integrals numerically through differential equations
Minor changes, accepted version
null
10.1007/JHEP03(2019)190
CP3-18-71, MCNET-18-32
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The computation of Feynman integrals is often the bottleneck of multi-loop calculations. We propose and implement a new method to efficiently evaluate such integrals in the physical region through the numerical integration of a suitable set of differential equations, where the initial conditions are provided in the unphysical region via the sector decomposition method. We present numerical results for a set of two-loop integrals, where the non-planar ones complete the master integrals for $gg\to\gamma\gamma$ and $q\bar{q}\to\gamma\gamma$ scattering mediated by the top quark.
[ { "created": "Fri, 7 Dec 2018 15:07:00 GMT", "version": "v1" }, { "created": "Wed, 27 Mar 2019 12:55:05 GMT", "version": "v2" } ]
2019-05-01
[ [ "Mandal", "Manoj K.", "" ], [ "Zhao", "Xiaoran", "" ] ]
The computation of Feynman integrals is often the bottleneck of multi-loop calculations. We propose and implement a new method to efficiently evaluate such integrals in the physical region through the numerical integration of a suitable set of differential equations, where the initial conditions are provided in the unphysical region via the sector decomposition method. We present numerical results for a set of two-loop integrals, where the non-planar ones complete the master integrals for $gg\to\gamma\gamma$ and $q\bar{q}\to\gamma\gamma$ scattering mediated by the top quark.
1310.0946
Song Mao
Song Mao, Wan Neng, Li Gang, Ma Wen-Gan, Zhang Ren-You, Guo Lei, Zhou Ya-Jin, and Guo Jian-You
Next-to-leading order QCD corrections to $HW^{\pm}\gamma$ production at the LHC
15 pages, 14 figures, accepted by Phys.Rev.D
Phys.Rev.D 88:076002 (2013)
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Higgs boson production associated with a $W$-boson and a photon at the Large Hadron Collider (LHC) can be used to probe the coupling between Higgs boson and vector gauge bosons and discover a signature of new physics. We present the precision predictions up to the QCD next-to-leading-order (NLO) in the standard model for this process involving the subsequential weak decays of the final Higgs and $W$-boson. The dependence of the leading order (LO) and the QCD NLO corrected integrated cross sections on the factorization/renormalization energy scale is studied. We provide the LO and QCD NLO corrected distributions of the transverse momenta and rapidities of final products. We find that the LO cross section is significantly enhanced by the QCD NLO correction, and the $K$-factor value is obviously related to the physical observables and the phase space regions.
[ { "created": "Thu, 3 Oct 2013 11:28:51 GMT", "version": "v1" } ]
2013-10-04
[ [ "Mao", "Song", "" ], [ "Neng", "Wan", "" ], [ "Gang", "Li", "" ], [ "Wen-Gan", "Ma", "" ], [ "Ren-You", "Zhang", "" ], [ "Lei", "Guo", "" ], [ "Ya-Jin", "Zhou", "" ], [ "Jian-You", "Guo", "" ] ]
The Higgs boson production associated with a $W$-boson and a photon at the Large Hadron Collider (LHC) can be used to probe the coupling between Higgs boson and vector gauge bosons and discover a signature of new physics. We present the precision predictions up to the QCD next-to-leading-order (NLO) in the standard model for this process involving the subsequential weak decays of the final Higgs and $W$-boson. The dependence of the leading order (LO) and the QCD NLO corrected integrated cross sections on the factorization/renormalization energy scale is studied. We provide the LO and QCD NLO corrected distributions of the transverse momenta and rapidities of final products. We find that the LO cross section is significantly enhanced by the QCD NLO correction, and the $K$-factor value is obviously related to the physical observables and the phase space regions.
1610.09971
Osamu Yasuda
Osamu Yasuda, Shinya Fukasawa and Monojit Ghosh
Complementarity Between Hyperkamiokande and DUNE
6 pages, 3 figures. Invited talk at 18th International Workshop on Neutrino Factories, Super beams and Beta beams (NuFact2016), August 21-27 2016, Quy Nhon, Vietnam
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this talk we present our results on the sensitivity to the neutrino mass hierarchy, the octant of the mixing angle and the CP phase in the future long baseline experiments T2HK and DUNE as well as in the atmospheric neutrino observation at Hyperkamiokande (HK).
[ { "created": "Mon, 31 Oct 2016 15:32:12 GMT", "version": "v1" } ]
2016-11-01
[ [ "Yasuda", "Osamu", "" ], [ "Fukasawa", "Shinya", "" ], [ "Ghosh", "Monojit", "" ] ]
In this talk we present our results on the sensitivity to the neutrino mass hierarchy, the octant of the mixing angle and the CP phase in the future long baseline experiments T2HK and DUNE as well as in the atmospheric neutrino observation at Hyperkamiokande (HK).
hep-ph/0702156
Jing-Jing Liu
Liu Jing-Jing, Ma Wen-Gan, Zhang Ren-You, Guo Lei, Jiang Yi, Han Liang
Full one-loop electroweak corrections to $h^0(H^0,A^0) H^\pm W^\mp$ associated productions at $e^+e^-$ linear colliders
22 pages, 20 figures, LaTex, to be appeared in PRD
Phys.Rev.D75:053007,2007
10.1103/PhysRevD.75.053007
null
hep-ph
null
We study the complete one-loop electroweak(EW) corrections to the processes of single charged Higgs boson production associated with a neutral Higgs boson$(h^0,H^0,A^0)$ and a gauge boson $W^\pm$ in the framework of the minimal supersymmetric standard model(MSSM). Numerical results at the ${\rm SPS1a'}$ benchmark point as proposed in the SPA project, are presented for demonstration. We find that for the process $e^+e^-\to h^0H^\pm W^\mp$ the EW relative correction can be either positive or negative and in the range of $-15%\sim 20%$ in our chosen parameter space. While for the processes $e^+e^-\to H^0(A^0)H^\pm W^\mp$ the corrections generally reduce the Born cross sections and the EW relative corrections are typically of order $-10%\sim -20%$.
[ { "created": "Thu, 15 Feb 2007 12:32:22 GMT", "version": "v1" }, { "created": "Fri, 16 Feb 2007 06:36:44 GMT", "version": "v2" } ]
2008-11-26
[ [ "Jing-Jing", "Liu", "" ], [ "Wen-Gan", "Ma", "" ], [ "Ren-You", "Zhang", "" ], [ "Lei", "Guo", "" ], [ "Yi", "Jiang", "" ], [ "Liang", "Han", "" ] ]
We study the complete one-loop electroweak(EW) corrections to the processes of single charged Higgs boson production associated with a neutral Higgs boson$(h^0,H^0,A^0)$ and a gauge boson $W^\pm$ in the framework of the minimal supersymmetric standard model(MSSM). Numerical results at the ${\rm SPS1a'}$ benchmark point as proposed in the SPA project, are presented for demonstration. We find that for the process $e^+e^-\to h^0H^\pm W^\mp$ the EW relative correction can be either positive or negative and in the range of $-15%\sim 20%$ in our chosen parameter space. While for the processes $e^+e^-\to H^0(A^0)H^\pm W^\mp$ the corrections generally reduce the Born cross sections and the EW relative corrections are typically of order $-10%\sim -20%$.
hep-ph/9412202
null
M. A. Braun
High-colour pomerons with a running coupling constant in the Hartree-Fock approximation
8 pages, LaTeX, no figures
Phys.Lett. B351 (1995) 528-532
10.1016/0370-2693(95)00396-3
US-FT/20-94
hep-ph
null
The Hartree-Fock approximation is applied to study the "high-colour pomerons" in the system of many reggeized gluons with a running QCD coupling constant. It is shown that, contrary to the fixed coupling case, the high-colour pomerons result supercritical, although with a smaller intercept than the multipomeron states.
[ { "created": "Thu, 1 Dec 1994 02:58:26 GMT", "version": "v1" } ]
2009-10-28
[ [ "Braun", "M. A.", "" ] ]
The Hartree-Fock approximation is applied to study the "high-colour pomerons" in the system of many reggeized gluons with a running QCD coupling constant. It is shown that, contrary to the fixed coupling case, the high-colour pomerons result supercritical, although with a smaller intercept than the multipomeron states.
2205.01699
Basabendu Barman
Basabendu Barman, Ashmita Das, Soumitra Sengupta
New $W$-Boson mass in the light of doubly warped braneworld model
6 pages, 2 figures
null
null
PI-UAN-2022-715FT
hep-ph
http://creativecommons.org/licenses/by/4.0/
The recent observation by CDF collaboration has disclosed a modification in the mass of the $W$ boson. In this regard we show that this modification in the mass of the $W$ boson can be well explained in the background of a 6-dimensional warped geometry model, where the double warping is associated with the two extra spatial dimensions. We consider that all the Standard Model fields are residing in the bulk, where the bulk Higgs field gives rise to the spontaneous symmetry breaking in the 6-dimensional spacetime. Allowing a little hierarchy between the two moduli we exactly obtain the observed mass for the $W$ boson, which is identified as the lowest lying Kaluza-Klein mass mode of the bulk $W$ boson on the $(3+1)$ dimensional visible brane. The essential feature of the 5-dimensional Randall-Sundrum scenario such as the resolution of the gauge hierarchy problem without introducing any intermediate scale between the Planck and the TeV scale, remains intact.
[ { "created": "Tue, 3 May 2022 18:00:06 GMT", "version": "v1" } ]
2022-05-05
[ [ "Barman", "Basabendu", "" ], [ "Das", "Ashmita", "" ], [ "Sengupta", "Soumitra", "" ] ]
The recent observation by CDF collaboration has disclosed a modification in the mass of the $W$ boson. In this regard we show that this modification in the mass of the $W$ boson can be well explained in the background of a 6-dimensional warped geometry model, where the double warping is associated with the two extra spatial dimensions. We consider that all the Standard Model fields are residing in the bulk, where the bulk Higgs field gives rise to the spontaneous symmetry breaking in the 6-dimensional spacetime. Allowing a little hierarchy between the two moduli we exactly obtain the observed mass for the $W$ boson, which is identified as the lowest lying Kaluza-Klein mass mode of the bulk $W$ boson on the $(3+1)$ dimensional visible brane. The essential feature of the 5-dimensional Randall-Sundrum scenario such as the resolution of the gauge hierarchy problem without introducing any intermediate scale between the Planck and the TeV scale, remains intact.
1504.06491
Antoni Szczurek
Antoni Szczurek
Double parton scattering at high energies
23 pages, 21 figures, 1 table, a short review talk at EPHIPHANY2015, conference on Future High Energy Colliders
null
10.5506/APhysPolB.46.1415
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We discuss a few examples of rich newly developing field of double parton scattering. We start our presentation from production of two pairs of charm quark-antiquark and argue that it is the golden reaction to study the double parton scattering effects. In addition to the DPS we consider briefly also mechanism of single parton scattering and show that it gives much smaller contribution to the $c \bar c c \bar c$ final state. Next we discuss a perturbative parton-splitting mechanism which should be included in addition to the conventional DPS mechanism. We show that the presence of this mechanism unavoidably leads to collision energy and other kinematical variables dependence of so-called $\sigma_{eff}$ parameter being extracted from different experiments. Next we briefly discuss production of four jets. We concentrate on estimation of the contribution of DPS for jets remote in rapidity. Understanding of this contribution is very important in the context of searches for BFKL effects known under the the name Mueller-Navelet jets. We discuss the situation in a more general context. Finally we briefly mention about DPS effects in production of $W^+ W^-$. Outlook closes the presentation.
[ { "created": "Fri, 24 Apr 2015 13:07:25 GMT", "version": "v1" } ]
2015-10-28
[ [ "Szczurek", "Antoni", "" ] ]
We discuss a few examples of rich newly developing field of double parton scattering. We start our presentation from production of two pairs of charm quark-antiquark and argue that it is the golden reaction to study the double parton scattering effects. In addition to the DPS we consider briefly also mechanism of single parton scattering and show that it gives much smaller contribution to the $c \bar c c \bar c$ final state. Next we discuss a perturbative parton-splitting mechanism which should be included in addition to the conventional DPS mechanism. We show that the presence of this mechanism unavoidably leads to collision energy and other kinematical variables dependence of so-called $\sigma_{eff}$ parameter being extracted from different experiments. Next we briefly discuss production of four jets. We concentrate on estimation of the contribution of DPS for jets remote in rapidity. Understanding of this contribution is very important in the context of searches for BFKL effects known under the the name Mueller-Navelet jets. We discuss the situation in a more general context. Finally we briefly mention about DPS effects in production of $W^+ W^-$. Outlook closes the presentation.
1702.05281
Igor Altsybeev
Igor Altsybeev, Grigory Feofilov
Azimuthal flow in hadron collisions from quark-gluon string repulsion
9 pages, http://dx.doi.org/10.1051/epjconf/201612504011
EPJ Web of Conferences 125, 04011 (2016)
10.1051/epjconf/201612504011
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Color flux tubes (quark-gluon strings), formed at early stages of hadron-hadron collisions, may overlap in case of sufficiently high densities and interact, producing long-range azimuthal correlations. In the hypothesis of repulsive interaction, each string may acquire, before the hadronization, the additional transverse boost, which is an efficient sum of all accounted string-string interactions. This modifies transverse momenta to the particles formed in string decay, leading to modification of event-wise observables, like azimuthal asymmetry of two-particle correlations, over a wide range of rapidity. In this article we discuss results of Monte Carlo model with string repulsion, where efficient string-string interaction radius is introduced. We show that the effect of string repulsion can be the main dynamic origin of the elliptic flow and of the higher harmonics, which are reflected in the complicated structures observed in two-particle long-range correlation topology in nucleus-nucleus collisions at RHIC and at LHC.
[ { "created": "Fri, 17 Feb 2017 09:49:11 GMT", "version": "v1" } ]
2017-02-22
[ [ "Altsybeev", "Igor", "" ], [ "Feofilov", "Grigory", "" ] ]
Color flux tubes (quark-gluon strings), formed at early stages of hadron-hadron collisions, may overlap in case of sufficiently high densities and interact, producing long-range azimuthal correlations. In the hypothesis of repulsive interaction, each string may acquire, before the hadronization, the additional transverse boost, which is an efficient sum of all accounted string-string interactions. This modifies transverse momenta to the particles formed in string decay, leading to modification of event-wise observables, like azimuthal asymmetry of two-particle correlations, over a wide range of rapidity. In this article we discuss results of Monte Carlo model with string repulsion, where efficient string-string interaction radius is introduced. We show that the effect of string repulsion can be the main dynamic origin of the elliptic flow and of the higher harmonics, which are reflected in the complicated structures observed in two-particle long-range correlation topology in nucleus-nucleus collisions at RHIC and at LHC.
hep-ph/9901426
Robert Peschanski
R.A. Janik and R. Peschanski
Conformal invariance and QCD Pomeron vertices in the $1/N_c$ limit
16 pages, LATEX file, 1 .eps figure
Nucl.Phys.B549:280-292,1999
10.1016/S0550-3213(99)00165-0
t99/009 (SPhT,Saclay)
hep-ph hep-th
null
Using the dipole framework for QCD at small x in the 1/N_c limit, we derive the expression of the 1 -> p dipole multiplicity density in momentum space. This gives an analytical expression for the 1 -> p QCD Pomeron amplitudes in terms of one-loop integration of effective vertices in transverse momentum. Conformal invariance and a Hilbert space construction for dipole correlation functions are the main tools of the derivation. Relations with conformal field theories in the classical limit are discussed.
[ { "created": "Wed, 27 Jan 1999 09:25:34 GMT", "version": "v1" } ]
2008-11-26
[ [ "Janik", "R. A.", "" ], [ "Peschanski", "R.", "" ] ]
Using the dipole framework for QCD at small x in the 1/N_c limit, we derive the expression of the 1 -> p dipole multiplicity density in momentum space. This gives an analytical expression for the 1 -> p QCD Pomeron amplitudes in terms of one-loop integration of effective vertices in transverse momentum. Conformal invariance and a Hilbert space construction for dipole correlation functions are the main tools of the derivation. Relations with conformal field theories in the classical limit are discussed.
1811.01188
Murat Koksal
M. K\"oksal, A. A. Billur, A. Guti\'errez-Rodr\'iguez and M. A. Hern\'andez-Ru\'iz
The $\mu^+\mu^-$ collider to sensitivity estimates on the magnetic and electric dipole moments of the tau-lepton
26 Pages, 19 Figures, 3 Tables
null
10.1142/S0217751X19500763
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Using the effective Lagrangian formalism, the anomalous magnetic and electric dipole moments of the tau-lepton in the $\mu^{+}\mu^{-} \rightarrow \mu^{+}\gamma^{*} \gamma^{*} \mu^{-}\rightarrow \mu^{+}\tau \bar{\tau}\mu^{-}$ process at the future muon colliders at the $\sqrt{s}=1.5, 3$ and $6$ TeV are investigated. In addition, the bounds at the $95\%$ confidence level on the dipole moments of the tau-lepton using different integrated luminosities are estimated. It is shown that the $\mu^{+}\mu^{-} \rightarrow \mu^{+}\gamma^{*} \gamma^{*} \mu^{-}\rightarrow \mu^{+}\tau \bar{\tau}\mu^{-}$ process leads to a remarkable improvement in the existing experimental bounds on the anomalous magnetic and electric dipole moments of the tau-lepton.
[ { "created": "Sat, 3 Nov 2018 10:28:21 GMT", "version": "v1" } ]
2019-06-26
[ [ "Köksal", "M.", "" ], [ "Billur", "A. A.", "" ], [ "Gutiérrez-Rodríguez", "A.", "" ], [ "Hernández-Ruíz", "M. A.", "" ] ]
Using the effective Lagrangian formalism, the anomalous magnetic and electric dipole moments of the tau-lepton in the $\mu^{+}\mu^{-} \rightarrow \mu^{+}\gamma^{*} \gamma^{*} \mu^{-}\rightarrow \mu^{+}\tau \bar{\tau}\mu^{-}$ process at the future muon colliders at the $\sqrt{s}=1.5, 3$ and $6$ TeV are investigated. In addition, the bounds at the $95\%$ confidence level on the dipole moments of the tau-lepton using different integrated luminosities are estimated. It is shown that the $\mu^{+}\mu^{-} \rightarrow \mu^{+}\gamma^{*} \gamma^{*} \mu^{-}\rightarrow \mu^{+}\tau \bar{\tau}\mu^{-}$ process leads to a remarkable improvement in the existing experimental bounds on the anomalous magnetic and electric dipole moments of the tau-lepton.
1310.2196
Patrick Draper
Michael Dine and Patrick Draper
Anomaly Mediation in Local Effective Theories
13 pg. v2: minor typos corrected; v3: references added, accepted for publication in JHEP
null
10.1007/JHEP02(2014)069
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The phenomenon known as ``anomaly mediation" can be understood in a variety of ways. Rather than an anomaly, certain gaugino bilinear terms are required by local supersymmetry and gauge invariance (the derivation of these terms is in some cases related to anomalies in scale invariance or $R$ symmetries). We explain why the gaugino bilinear is required in supersymmetric gauge theories with varying number of colors and flavors. By working in the Higgs phase, gauging a flavor group, or working below the scale of gaugino condensation, each of these theories has a local effective description in which we can identify the bilinear term, establishing its necessity in the microscopic theory. For example, in theories that exhibit gaugino condensation, the potential in the very low energy theory is supersymmetric precisely due to the relation between the nonperturbative superpotential and the gaugino bilinear terms. Similarly, the gravitino mass appears from its coupling to the gaugino bilinear.
[ { "created": "Tue, 8 Oct 2013 17:16:21 GMT", "version": "v1" }, { "created": "Wed, 9 Oct 2013 20:10:24 GMT", "version": "v2" }, { "created": "Fri, 21 Feb 2014 23:44:52 GMT", "version": "v3" } ]
2015-06-17
[ [ "Dine", "Michael", "" ], [ "Draper", "Patrick", "" ] ]
The phenomenon known as ``anomaly mediation" can be understood in a variety of ways. Rather than an anomaly, certain gaugino bilinear terms are required by local supersymmetry and gauge invariance (the derivation of these terms is in some cases related to anomalies in scale invariance or $R$ symmetries). We explain why the gaugino bilinear is required in supersymmetric gauge theories with varying number of colors and flavors. By working in the Higgs phase, gauging a flavor group, or working below the scale of gaugino condensation, each of these theories has a local effective description in which we can identify the bilinear term, establishing its necessity in the microscopic theory. For example, in theories that exhibit gaugino condensation, the potential in the very low energy theory is supersymmetric precisely due to the relation between the nonperturbative superpotential and the gaugino bilinear terms. Similarly, the gravitino mass appears from its coupling to the gaugino bilinear.
2002.12534
Shohei Okawa
Junichiro Kawamura, Shohei Okawa, Yuji Omura
Current status and muon $g-2$ explanation of lepton portal dark matter
34+21 pages, 12 figures, 3 tables; v2, references added, typos corrected
null
10.1007/JHEP08(2020)042
null
hep-ph astro-ph.CO astro-ph.HE hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we summarize phenomenology in lepton portal dark matter (DM) models, where DM couples to leptons and extra leptons/sleptons. There are several possible setups: complex/real scalar DM and Dirac/Majorana fermion DM. In addition, there are choices for the lepton chirality that couples to DM. We discuss the prediction of each model and compare it with the latest experimental constraints from the DM, the LHC, and the flavor experiments. We also propose a simple setup to achieve the discrepancy in the anomalous magnetic moment of muon.
[ { "created": "Fri, 28 Feb 2020 04:04:08 GMT", "version": "v1" }, { "created": "Fri, 20 Mar 2020 06:50:59 GMT", "version": "v2" } ]
2020-08-26
[ [ "Kawamura", "Junichiro", "" ], [ "Okawa", "Shohei", "" ], [ "Omura", "Yuji", "" ] ]
In this paper, we summarize phenomenology in lepton portal dark matter (DM) models, where DM couples to leptons and extra leptons/sleptons. There are several possible setups: complex/real scalar DM and Dirac/Majorana fermion DM. In addition, there are choices for the lepton chirality that couples to DM. We discuss the prediction of each model and compare it with the latest experimental constraints from the DM, the LHC, and the flavor experiments. We also propose a simple setup to achieve the discrepancy in the anomalous magnetic moment of muon.
1002.2356
Gennady Kozlov
G.A. Kozlov
Two-Photon Correlations in $pp$ Collisions
12 pages
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It is well understood that the studies of correlations between produced particles, the effects of coherence and chaoticity, an estimation of particle emitting source size play an important role in high energy physics [1]. First of all, we mean the investigation of the space-time extension or even squeezing of particle sources via the multiparticle quantum-statistics correlation. We consider the two-photon correlation function that can provide the space-time information about the Higgs-boson source in thermal environment and estimate the Higgs-boson mass for the first time.
[ { "created": "Thu, 11 Feb 2010 15:06:20 GMT", "version": "v1" }, { "created": "Sat, 1 May 2010 08:43:08 GMT", "version": "v2" } ]
2010-05-04
[ [ "Kozlov", "G. A.", "" ] ]
It is well understood that the studies of correlations between produced particles, the effects of coherence and chaoticity, an estimation of particle emitting source size play an important role in high energy physics [1]. First of all, we mean the investigation of the space-time extension or even squeezing of particle sources via the multiparticle quantum-statistics correlation. We consider the two-photon correlation function that can provide the space-time information about the Higgs-boson source in thermal environment and estimate the Higgs-boson mass for the first time.
1207.4483
Jernej Kamenik
Sebastien Descotes-Genon and Jernej F. Kamenik
On the origin of the D0 like-sign dimuon charge asymmetry
Corrected discussion of the SM contributions to the direct semileptonic CP asymmetries in B decays. Main results and conclusions unchanged
null
10.1103/PhysRevD.87.074036
LPT-ORSAY/12-83
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We reconsider the recent observation by the D0 experiment of a sizable like-sign dimuon charge asymmetry, highlighting that it could be affected by CP-violating New Physics contributions not only in Bd- and Bs-meson mixings, but also in semileptonic decays of b and c quarks producing muons. The D0, measurement could be reconciled with the Standard Model expectations for neutral-meson mixings, provided that the CP asymmetry in semileptonic b (c) decays reaches 0.3 % (1%). Such effects, which lie within the available (rather loose) experimental bounds, would be clear indications of New Physics and should be investigated experimentally.
[ { "created": "Wed, 18 Jul 2012 20:00:04 GMT", "version": "v1" }, { "created": "Tue, 30 Apr 2013 14:49:24 GMT", "version": "v2" }, { "created": "Tue, 1 Sep 2015 19:28:33 GMT", "version": "v3" } ]
2015-09-02
[ [ "Descotes-Genon", "Sebastien", "" ], [ "Kamenik", "Jernej F.", "" ] ]
We reconsider the recent observation by the D0 experiment of a sizable like-sign dimuon charge asymmetry, highlighting that it could be affected by CP-violating New Physics contributions not only in Bd- and Bs-meson mixings, but also in semileptonic decays of b and c quarks producing muons. The D0, measurement could be reconciled with the Standard Model expectations for neutral-meson mixings, provided that the CP asymmetry in semileptonic b (c) decays reaches 0.3 % (1%). Such effects, which lie within the available (rather loose) experimental bounds, would be clear indications of New Physics and should be investigated experimentally.
2008.03847
A. Bashir
Aftab Ahmad, Adnan Bashir, Marco A. Bedolla, J.J. Cobos-Mart\'inez
Color, Flavor, Temperature and Magnetic Field Dependence of QCD Phase Diagram: Magnetic Catalysis and its Inverse
12 pages, 19 figures
null
10.1088/1361-6471/abd88f
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study dynamical chiral symmetry breaking for quarks in the fundamental representation of $SU(N_c)$ for $N_f$ number of light quark flavors. We also investigate the phase diagram of quantum chromodynamics at finite temperature $T$ and/or in the presence of a constant external magnetic field $eB$. The unified formalism for this analysis is provided by a symmetry-preserving Schwinger-Dyson equations treatment of a vector$\times$vector contact interaction model which encodes several well-established features of quantum chromodynamics to mimic the latter as closely as possible. Deconfinement and chiral symmetry restoration are triggered above a critical value of $N_f$ at $T=0=eB$. On the other hand, increasing temperature itself screens strong interactions, thus ensuring that a smaller value of $N_f$ is sufficient to restore chiral symmetry at higher temperatures. We also observe the well-known phenomenon of magnetic catalysis for a strong enough magnetic field. However, we note that if the effective coupling strength of the model decreases as a function of magnetic field, it can trigger inverse magnetic catalysis in a certain window of this functional dependence. Our model allows for the simultaneous onset of dynamical chiral symmetry breaking and confinement for each case. Qualitative as well as quantitative predictions of our simple but effective model are in reasonably satisfactory agreement with lattice results and other reliable and refined predictions based upon intricate continuum studies of quantum chromodynamics.
[ { "created": "Mon, 10 Aug 2020 00:54:09 GMT", "version": "v1" } ]
2021-07-07
[ [ "Ahmad", "Aftab", "" ], [ "Bashir", "Adnan", "" ], [ "Bedolla", "Marco A.", "" ], [ "Cobos-Martínez", "J. J.", "" ] ]
We study dynamical chiral symmetry breaking for quarks in the fundamental representation of $SU(N_c)$ for $N_f$ number of light quark flavors. We also investigate the phase diagram of quantum chromodynamics at finite temperature $T$ and/or in the presence of a constant external magnetic field $eB$. The unified formalism for this analysis is provided by a symmetry-preserving Schwinger-Dyson equations treatment of a vector$\times$vector contact interaction model which encodes several well-established features of quantum chromodynamics to mimic the latter as closely as possible. Deconfinement and chiral symmetry restoration are triggered above a critical value of $N_f$ at $T=0=eB$. On the other hand, increasing temperature itself screens strong interactions, thus ensuring that a smaller value of $N_f$ is sufficient to restore chiral symmetry at higher temperatures. We also observe the well-known phenomenon of magnetic catalysis for a strong enough magnetic field. However, we note that if the effective coupling strength of the model decreases as a function of magnetic field, it can trigger inverse magnetic catalysis in a certain window of this functional dependence. Our model allows for the simultaneous onset of dynamical chiral symmetry breaking and confinement for each case. Qualitative as well as quantitative predictions of our simple but effective model are in reasonably satisfactory agreement with lattice results and other reliable and refined predictions based upon intricate continuum studies of quantum chromodynamics.
hep-ph/9604228
null
C.Q. Geng, I.J. Hsu and Y.C. Lin
Study of Long Distance Contributions to $K\to n\pi\nu\bar{\nu}$
13 pages, LaTeX file
Phys.Rev. D54 (1996) 877-881
10.1103/PhysRevD.54.877
null
hep-ph
null
We calculate long distance contributions to $K\to\pi\nu\bar{\nu}\,,\ \pi\pi\nu\bar{\nu}$, and $\pi\pi\pi\nu\bar{\nu}$ modes within the framework of chiral perturbation theory. We find that these contributions to decay rates of $K\to \pi\nu\bar{\nu}$ and $K\to \pi\pi\nu\bar{\nu}$ in the chiral logarithmic approximation are at least seven orders of magnitude suppressed relative to those from the short distance parts. The long distance effects in this class of decays are therefore negligible.
[ { "created": "Wed, 3 Apr 1996 08:34:30 GMT", "version": "v1" } ]
2009-10-28
[ [ "Geng", "C. Q.", "" ], [ "Hsu", "I. J.", "" ], [ "Lin", "Y. C.", "" ] ]
We calculate long distance contributions to $K\to\pi\nu\bar{\nu}\,,\ \pi\pi\nu\bar{\nu}$, and $\pi\pi\pi\nu\bar{\nu}$ modes within the framework of chiral perturbation theory. We find that these contributions to decay rates of $K\to \pi\nu\bar{\nu}$ and $K\to \pi\pi\nu\bar{\nu}$ in the chiral logarithmic approximation are at least seven orders of magnitude suppressed relative to those from the short distance parts. The long distance effects in this class of decays are therefore negligible.
hep-ph/0503296
Gabriele Bodenmueller
Harald Fritzsch
The Spin Structure of the Constituent Quarks and of the Nucleon
7 pages
Eur.Phys.J.C44:59-61,2005
10.1140/epjc/s2005-02311-1
LMU 16/04
hep-ph
null
We define a constituent quark within QCD. It is shown that the spin of such a quark and hence also the spin of the nucleon reduced due to $\bar{q}q$-pairs, in agreement with experiment. A solution to the spin problem is given.
[ { "created": "Thu, 31 Mar 2005 13:46:34 GMT", "version": "v1" } ]
2009-01-07
[ [ "Fritzsch", "Harald", "" ] ]
We define a constituent quark within QCD. It is shown that the spin of such a quark and hence also the spin of the nucleon reduced due to $\bar{q}q$-pairs, in agreement with experiment. A solution to the spin problem is given.
2407.20330
Juan Antonio Aguilar-Saavedra
J. A. Aguilar-Saavedra
Toponium Hunter's Guide
LaTeX 10 pages
null
null
IFT-UAM/CSIC-24-112, CERN-TH-2024-123
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We address the discovery and characterisation of toponium production at the Large Hadron Collider. In the dilepton decay mode, multivariate analyses of spin and colour observables could provide evidence that an excess of events present near the $t \bar t$ threshold corresponds to a spin-zero colour singlet. The semileptonic decay mode may also exhibit an excess near threshold, but is not expected to play any role in the toponium characterisation.
[ { "created": "Mon, 29 Jul 2024 18:00:04 GMT", "version": "v1" } ]
2024-07-31
[ [ "Aguilar-Saavedra", "J. A.", "" ] ]
We address the discovery and characterisation of toponium production at the Large Hadron Collider. In the dilepton decay mode, multivariate analyses of spin and colour observables could provide evidence that an excess of events present near the $t \bar t$ threshold corresponds to a spin-zero colour singlet. The semileptonic decay mode may also exhibit an excess near threshold, but is not expected to play any role in the toponium characterisation.
2104.12656
Jianpeng Dai
Jianpeng Dai and Tao Liu and Jin Min Yang
An explicit calculation of pseudo-goldstino mass at the leading three-loop level
13 pages,2 figures We fixed some taypo issues
null
10.1007/JHEP06(2021)175
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Pseudo-goldstinos appear in the scenario of multi-sector SUSY breaking. Unlike the true goldstino which is massless and absorbed by the gravitino, pseudo-goldstinos could obtain mass from radiative effects. In this note, working in the scenario of two-sector SUSY breaking with gauge mediation, we explicitly calculate the pseudo-goldstino mass at the leading three-loop level and provide the analytical results. In our calculation we consider the general case of messenger masses (not necessarily equal) and include the higher order terms of SUSY breaking scales. Our results can reproduce the numerical value estimated previously at the leading order of SUSY breaking scales with the assumption of equal messenger masses. It turns out that the results are very sensitive to the ratio of messenger masses, while the higher order terms of SUSY breaking scales are rather small in magnitude. Depending on the ratio of messenger masses, the pseudo-goldstino mass can be as low as ${{\cal O} (0.1)}$ GeV.
[ { "created": "Mon, 26 Apr 2021 15:34:00 GMT", "version": "v1" }, { "created": "Sun, 4 Jul 2021 05:12:30 GMT", "version": "v2" } ]
2021-07-14
[ [ "Dai", "Jianpeng", "" ], [ "Liu", "Tao", "" ], [ "Yang", "Jin Min", "" ] ]
Pseudo-goldstinos appear in the scenario of multi-sector SUSY breaking. Unlike the true goldstino which is massless and absorbed by the gravitino, pseudo-goldstinos could obtain mass from radiative effects. In this note, working in the scenario of two-sector SUSY breaking with gauge mediation, we explicitly calculate the pseudo-goldstino mass at the leading three-loop level and provide the analytical results. In our calculation we consider the general case of messenger masses (not necessarily equal) and include the higher order terms of SUSY breaking scales. Our results can reproduce the numerical value estimated previously at the leading order of SUSY breaking scales with the assumption of equal messenger masses. It turns out that the results are very sensitive to the ratio of messenger masses, while the higher order terms of SUSY breaking scales are rather small in magnitude. Depending on the ratio of messenger masses, the pseudo-goldstino mass can be as low as ${{\cal O} (0.1)}$ GeV.
hep-ph/9702228
Oleg Teryaev
N. Kawka, O. V. Teryaev and O.L. Veretin
Dispersive Approach to the Trace Anomaly
LATEX, 10 pages, 2 figures included to the file. The references are updated; the discussion of the anomalous breaking of translation invariance is accordingly enlarged
null
null
null
hep-ph
null
In the scalar $\phi^4$ field model the dispersive approach to the trace anomaly is proposed. It is shown that it is impossible to get dispersion representation for all formfactors so that preserve both the translation and dilatation Ward identities. Subtractions which preserve energy-momentum conservation violate the classical trace Ward--Takahashi identity and give rise to an anomalous contribution to the matrix element of stress tensor $\theta_\mu^\nu$. This contribution coincides with one-loop $\beta$-function in accordance with previous analyses based on RG technique.
[ { "created": "Mon, 3 Feb 1997 15:20:38 GMT", "version": "v1" }, { "created": "Sun, 23 Feb 1997 14:56:21 GMT", "version": "v2" }, { "created": "Sat, 8 Mar 1997 11:13:51 GMT", "version": "v3" } ]
2008-02-03
[ [ "Kawka", "N.", "" ], [ "Teryaev", "O. V.", "" ], [ "Veretin", "O. L.", "" ] ]
In the scalar $\phi^4$ field model the dispersive approach to the trace anomaly is proposed. It is shown that it is impossible to get dispersion representation for all formfactors so that preserve both the translation and dilatation Ward identities. Subtractions which preserve energy-momentum conservation violate the classical trace Ward--Takahashi identity and give rise to an anomalous contribution to the matrix element of stress tensor $\theta_\mu^\nu$. This contribution coincides with one-loop $\beta$-function in accordance with previous analyses based on RG technique.
hep-ph/0605084
Georg Kreyerhoff
Saul Barshay and Georg Kreyerhoff
A vertex-structure model for new direct CP-violating effects in Bbar^0(B^0) -> phi K_S and in B^-+ -> pi^-+ eta' (eta)
12 pages including 3 figures
Mod.Phys.Lett.A21:2729-2738,2006
10.1142/S0217732306021700
null
hep-ph
null
We consider effective Lagrangian models of CP-violating vertex structure in which a $b -> uW$ vertex, proportional to $s_{13}e^{-i\delta_{13}}$ with $s_{13}$ very small (milliweak interaction) and $\delta_{13}$ large, is dynamically generated. A consequent, enhanced CP-violating vertex for $b\to sg$ results in an enhanced CP-violating phase in the ratio of amplitudes for $\bbar \to \phi \KS$. We estimate that this can significantly change the $S$ parameter from the value expected in the standard model.
[ { "created": "Mon, 8 May 2006 18:43:25 GMT", "version": "v1" }, { "created": "Tue, 9 May 2006 06:08:34 GMT", "version": "v2" }, { "created": "Mon, 3 Jul 2006 14:46:31 GMT", "version": "v3" } ]
2008-11-26
[ [ "Barshay", "Saul", "" ], [ "Kreyerhoff", "Georg", "" ] ]
We consider effective Lagrangian models of CP-violating vertex structure in which a $b -> uW$ vertex, proportional to $s_{13}e^{-i\delta_{13}}$ with $s_{13}$ very small (milliweak interaction) and $\delta_{13}$ large, is dynamically generated. A consequent, enhanced CP-violating vertex for $b\to sg$ results in an enhanced CP-violating phase in the ratio of amplitudes for $\bbar \to \phi \KS$. We estimate that this can significantly change the $S$ parameter from the value expected in the standard model.
1507.02965
Tim Morris Prof
Nick Evans, Tim R. Morris and Marc Scott
Translational Symmetry Breaking in Higgs & Gauge Theory, and the Cosmological Constant
9 pages, 1 figure; minor changes. Version to be published in PRD
Phys. Rev. D 93, 025019 (2016)
10.1103/PhysRevD.93.025019
null
hep-ph gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We argue, at a very basic effective field theory level, that higher dimension operators in scalar theories that break symmetries at scales close to their ultraviolet completion cutoff, include terms that favour the breaking of translation (Lorentz) invariance, potentially resulting in striped, chequered board or general crystal-like phases. Such descriptions can be thought of as the effective low energy description of QCD-like gauge theories near their strong coupling scale where terms involving higher dimension operators are generated. Our low energy theory consists of scalar fields describing operators such as $\bar{q} q$ and $\bar{q} F^{(2n)} q$. Such scalars can have kinetic mixing terms that generate effective momentum dependent contributions to the mass matrix. We show that these can destabilize the translationally invariant vacuum. It is possible that in some real gauge theory such operators could become sufficiently dominant to realize such phases and it would be interesting to look for them in lattice simulations. We present a holographic model of the same phenomena which includes RG running. A key phenomenological motive to look at such states is recent work that shows that the non-linear response in $R^2$ gravity to such short range fluctuations can mimic a cosmological constant. Intriguingly in a cosmology with such a Starobinsky inflation term, to generate the observed value of the present day acceleration would require stripes at the electroweak scale. Unfortunately, low energy phenomenological constraints on Lorentz violation in the electron-photon system appear to strongly rule out any such possibility outside of a disconnected dark sector.
[ { "created": "Fri, 10 Jul 2015 16:54:05 GMT", "version": "v1" }, { "created": "Sun, 17 Jan 2016 18:34:55 GMT", "version": "v2" } ]
2016-01-27
[ [ "Evans", "Nick", "" ], [ "Morris", "Tim R.", "" ], [ "Scott", "Marc", "" ] ]
We argue, at a very basic effective field theory level, that higher dimension operators in scalar theories that break symmetries at scales close to their ultraviolet completion cutoff, include terms that favour the breaking of translation (Lorentz) invariance, potentially resulting in striped, chequered board or general crystal-like phases. Such descriptions can be thought of as the effective low energy description of QCD-like gauge theories near their strong coupling scale where terms involving higher dimension operators are generated. Our low energy theory consists of scalar fields describing operators such as $\bar{q} q$ and $\bar{q} F^{(2n)} q$. Such scalars can have kinetic mixing terms that generate effective momentum dependent contributions to the mass matrix. We show that these can destabilize the translationally invariant vacuum. It is possible that in some real gauge theory such operators could become sufficiently dominant to realize such phases and it would be interesting to look for them in lattice simulations. We present a holographic model of the same phenomena which includes RG running. A key phenomenological motive to look at such states is recent work that shows that the non-linear response in $R^2$ gravity to such short range fluctuations can mimic a cosmological constant. Intriguingly in a cosmology with such a Starobinsky inflation term, to generate the observed value of the present day acceleration would require stripes at the electroweak scale. Unfortunately, low energy phenomenological constraints on Lorentz violation in the electron-photon system appear to strongly rule out any such possibility outside of a disconnected dark sector.
1212.3247
Ivo de Medeiros Varzielas
Ivo de Medeiros Varzielas, Lu\'is Lavoura
Flavour models for TM1 lepton mixing
23 pages, 5 figures. v2: references added. v3: accepted by J. Phys. G
null
10.1088/0954-3899/40/8/085002
DO-TH/12-40; CFTP/12-018
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a framework for lepton flavour models such that the first column of the lepton mixing matrix is (2,-1,-1)/sqrt(6). We show that the flavour symmetry group adequate for this purpose is S4. Our models are based on a vacuum alignment that can be obtained in a supersymmetric framework.
[ { "created": "Thu, 13 Dec 2012 18:12:12 GMT", "version": "v1" }, { "created": "Wed, 19 Dec 2012 20:12:12 GMT", "version": "v2" }, { "created": "Thu, 20 Jun 2013 13:20:00 GMT", "version": "v3" } ]
2015-06-12
[ [ "Varzielas", "Ivo de Medeiros", "" ], [ "Lavoura", "Luís", "" ] ]
We present a framework for lepton flavour models such that the first column of the lepton mixing matrix is (2,-1,-1)/sqrt(6). We show that the flavour symmetry group adequate for this purpose is S4. Our models are based on a vacuum alignment that can be obtained in a supersymmetric framework.
hep-ph/0210018
Steven D. Bass
Steven D. Bass
Manifestations of anomalous glue: light-mass exotic mesons and the eta-prime nucleon coupling constant
Talk presented at QNP2002 (FZ-Juelich), 3 pages, 1 figure
null
null
null
hep-ph
null
The light-mass exotics with J^{PC}=1^{-+} observed at BNL and CERN may have a simple explanation as dynamically generated resonances in eta-prime pi rescattering in the final state interaction. This dynamics is mediated by the same anomalous glue which also generates the large mass of the eta-prime. OZI violating processes are also potentially important to eta-prime production in proton-proton collisions close to threshold.
[ { "created": "Tue, 1 Oct 2002 14:17:01 GMT", "version": "v1" }, { "created": "Tue, 15 Oct 2002 13:29:14 GMT", "version": "v2" } ]
2007-05-23
[ [ "Bass", "Steven D.", "" ] ]
The light-mass exotics with J^{PC}=1^{-+} observed at BNL and CERN may have a simple explanation as dynamically generated resonances in eta-prime pi rescattering in the final state interaction. This dynamics is mediated by the same anomalous glue which also generates the large mass of the eta-prime. OZI violating processes are also potentially important to eta-prime production in proton-proton collisions close to threshold.
1110.2419
Wally Melnitchouk
O. Hen, A. Accardi, W. Melnitchouk, E. Piasetzky
Constraints on the large-x d/u ratio from electron-nucleus scattering at x>1
4 pages, 3 figures
null
10.1103/PhysRevD.84.117501
JLAB-THY-11-1447
hep-ph hep-ex nucl-ex nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Recently the ratio of neutron to proton structure functions F_2n/F_2p was extracted from a phenomenological correlation between the strength of the nuclear EMC effect and inclusive electron-nucleus cross section ratios at x>1. Within conventional models of nuclear smearing, this "in-medium correction" (IMC) extraction constrains the size of nuclear effects in the deuteron structure functions, from which the neutron structure function F_2n is usually extracted. The IMC data determine the resulting proton d/u quark distribution ratio, extrapolated to x=1, to be 0.23 +- 0.09 with a 90% confidence level. This is well below the SU(6) symmetry limit of 1/2 and significantly above the scalar diquark dominance limit of 0.
[ { "created": "Tue, 11 Oct 2011 16:33:19 GMT", "version": "v1" } ]
2015-05-30
[ [ "Hen", "O.", "" ], [ "Accardi", "A.", "" ], [ "Melnitchouk", "W.", "" ], [ "Piasetzky", "E.", "" ] ]
Recently the ratio of neutron to proton structure functions F_2n/F_2p was extracted from a phenomenological correlation between the strength of the nuclear EMC effect and inclusive electron-nucleus cross section ratios at x>1. Within conventional models of nuclear smearing, this "in-medium correction" (IMC) extraction constrains the size of nuclear effects in the deuteron structure functions, from which the neutron structure function F_2n is usually extracted. The IMC data determine the resulting proton d/u quark distribution ratio, extrapolated to x=1, to be 0.23 +- 0.09 with a 90% confidence level. This is well below the SU(6) symmetry limit of 1/2 and significantly above the scalar diquark dominance limit of 0.
hep-ph/0412134
Alexander Studenikin
Konstantin A. Kouzakov and Alexander I. Studenikin
Bound-state beta-decay of a neutron in a strong magnetic field
22 pages (revtex4), 1 figure; v2: more detailed discussion on astrophysical applications in conclusion section, accepted for publication in Phys. Rev. C
Phys.Rev. C72 (2005) 015502
10.1103/PhysRevC.72.015502
null
hep-ph
null
The beta-decay of a neutron into a bound $(pe^-)$ state and an antineutrino in the presence of a strong uniform magnetic field ($B \gtrsim 10^{13}$ G) is considered. The beta-decay process is treated within the framework of the standard model of weak interactions. A Bethe-Salpeter formalism is employed for description of the bound $(pe^-)$ system in a strong magnetic field. For the field strengths $10^{13}$ G$ \lesssim B \lesssim10^{18}$ G the estimate for the ratio of the bound-state decay rate $w_b$ and the usual (continuum-state) decay rate $w_c$ is derived. It is found that in such strong magnetic fields $w_b/w_c \sim 0.1-0.4$. This is in contrast to the field-free case, where $w_b/w_c \simeq 4.2 \times 10^{-6}$ [J. N. Bahcall, Phys. Rev. {\bf 124}, 495 (1961); L. L. Nemenov, Sov. J. Nucl. Phys. {\bf 15}, 582 (1972); X. Song, J. Phys. G: Nucl. Phys. {\bf 13}, 1023 (1987)]. The dependence of the ratio $w_b/w_c$ on the magnetic field strength $B$ exhibits a logarithmic-like behavior. The obtained results can be important for applications in astrophysics and cosmology.
[ { "created": "Thu, 9 Dec 2004 19:11:25 GMT", "version": "v1" }, { "created": "Thu, 16 Jun 2005 13:54:07 GMT", "version": "v2" } ]
2009-11-10
[ [ "Kouzakov", "Konstantin A.", "" ], [ "Studenikin", "Alexander I.", "" ] ]
The beta-decay of a neutron into a bound $(pe^-)$ state and an antineutrino in the presence of a strong uniform magnetic field ($B \gtrsim 10^{13}$ G) is considered. The beta-decay process is treated within the framework of the standard model of weak interactions. A Bethe-Salpeter formalism is employed for description of the bound $(pe^-)$ system in a strong magnetic field. For the field strengths $10^{13}$ G$ \lesssim B \lesssim10^{18}$ G the estimate for the ratio of the bound-state decay rate $w_b$ and the usual (continuum-state) decay rate $w_c$ is derived. It is found that in such strong magnetic fields $w_b/w_c \sim 0.1-0.4$. This is in contrast to the field-free case, where $w_b/w_c \simeq 4.2 \times 10^{-6}$ [J. N. Bahcall, Phys. Rev. {\bf 124}, 495 (1961); L. L. Nemenov, Sov. J. Nucl. Phys. {\bf 15}, 582 (1972); X. Song, J. Phys. G: Nucl. Phys. {\bf 13}, 1023 (1987)]. The dependence of the ratio $w_b/w_c$ on the magnetic field strength $B$ exhibits a logarithmic-like behavior. The obtained results can be important for applications in astrophysics and cosmology.
1002.4352
Peng Zhang
Peng Zhang
Improving the Excited Nucleon Spectrum in Hard-Wall AdS/QCD
11 pages, 2 figures. v2: references added. v3: add a section about the pion-nucleon coupling, published version
Phys.Rev.D81:114029,2010
10.1103/PhysRevD.81.114029
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We show that the nucleon spectrum in a hard-wall AdS/QCD model can be improved by use of a relatively large IR cutoff. All of the spin-1/2 nucleon masses listed in PDG can be fit quite well within 11%. The average error is remarkably only 4.66%.
[ { "created": "Tue, 23 Feb 2010 15:35:43 GMT", "version": "v1" }, { "created": "Tue, 2 Mar 2010 11:20:02 GMT", "version": "v2" }, { "created": "Thu, 1 Jul 2010 13:57:12 GMT", "version": "v3" } ]
2010-07-02
[ [ "Zhang", "Peng", "" ] ]
We show that the nucleon spectrum in a hard-wall AdS/QCD model can be improved by use of a relatively large IR cutoff. All of the spin-1/2 nucleon masses listed in PDG can be fit quite well within 11%. The average error is remarkably only 4.66%.
2109.08878
G.R. Boroun
G.R.Boroun
Non-linear corrections to the longitudinal structure function $F_{L}$ from the parametrization of $F_{2}$: Laplace transform approach
arXiv admin note: text overlap with arXiv:2108.09465
Eur. Phys. J. Plus (2022) 137:371
10.1140/epjp/s13360-022-02558-1
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
The non-linear corrections (NLC) to the longitudinal structure function in a limited approach is derived at low values of the Bjorken variable $x$ by using the Laplace transforms technique. The non-linear behavior of the longitudinal structure function is determined with respect to the Gribov-Levin-Ryskin Mueller-Qiu (GLR-MQ) and Altarelli-Martinelli (AM) equations. These results show that the non-linear longitudinal structure function can be determined directly in terms of the parametrization of $F_{2}(x,Q^{2})$ and the derivative of the proton structure function with respect to $\ln{Q^{2}}$. These corrections improve the behavior of the longitudinal structure function at low values of $Q^{2}$ in comparison with other parametrization methods.
[ { "created": "Sat, 18 Sep 2021 08:23:35 GMT", "version": "v1" }, { "created": "Wed, 22 Sep 2021 12:31:42 GMT", "version": "v2" }, { "created": "Sun, 10 Oct 2021 13:18:20 GMT", "version": "v3" }, { "created": "Wed, 17 Nov 2021 06:23:13 GMT", "version": "v4" } ]
2022-03-24
[ [ "Boroun", "G. R.", "" ] ]
The non-linear corrections (NLC) to the longitudinal structure function in a limited approach is derived at low values of the Bjorken variable $x$ by using the Laplace transforms technique. The non-linear behavior of the longitudinal structure function is determined with respect to the Gribov-Levin-Ryskin Mueller-Qiu (GLR-MQ) and Altarelli-Martinelli (AM) equations. These results show that the non-linear longitudinal structure function can be determined directly in terms of the parametrization of $F_{2}(x,Q^{2})$ and the derivative of the proton structure function with respect to $\ln{Q^{2}}$. These corrections improve the behavior of the longitudinal structure function at low values of $Q^{2}$ in comparison with other parametrization methods.
2106.16027
Gilles Couture
Gilles Couture
Solar wind bremsstrahlung off DM in our solar system
17 pages including 1 table, and 5 figures
null
10.1103/PhysRevD.105.055003
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider the possibility that the solar wind emits photons via bremsstrahlung when colliding with Dark Matter (DM) particles within the solar system. To this effect, we calculate the bremsstrahlung spectrum a proton would emit when colliding with a neutral spin-1/2 particle through the exchange of a scalar neutral particle. We assume a speed of 600 km/sec for the solar wind and assume that the speed of the dark matter halo is due to the motion of the sun through the galaxy, which we take as 300 km/sec. We assume a DM density of 0.3 GeV/cm^3 and a solar wind composed primarily of protons with a total rate of ejection mass set at 10^9kg/sec. We use a Monte Carlo technique to let this interaction take place within the solar system and calculate the photon rate an observer would detect on Earth or at the edge of the solar system as a function of photon energy. We find that the rates are in general very small but could be observable in some scenarios at wavelengths in the mm or cm range.
[ { "created": "Wed, 30 Jun 2021 12:51:23 GMT", "version": "v1" }, { "created": "Wed, 14 Jul 2021 15:36:16 GMT", "version": "v2" } ]
2022-03-23
[ [ "Couture", "Gilles", "" ] ]
We consider the possibility that the solar wind emits photons via bremsstrahlung when colliding with Dark Matter (DM) particles within the solar system. To this effect, we calculate the bremsstrahlung spectrum a proton would emit when colliding with a neutral spin-1/2 particle through the exchange of a scalar neutral particle. We assume a speed of 600 km/sec for the solar wind and assume that the speed of the dark matter halo is due to the motion of the sun through the galaxy, which we take as 300 km/sec. We assume a DM density of 0.3 GeV/cm^3 and a solar wind composed primarily of protons with a total rate of ejection mass set at 10^9kg/sec. We use a Monte Carlo technique to let this interaction take place within the solar system and calculate the photon rate an observer would detect on Earth or at the edge of the solar system as a function of photon energy. We find that the rates are in general very small but could be observable in some scenarios at wavelengths in the mm or cm range.
1802.02133
Pedro Simoni Pasquini
O. G. Miranda, Pedro Pasquini, M. T\'ortola, and J. W. F. Valle
Exploring the Potential of Short-Baseline Physics at Fermilab
16 pages, 9 figures, 2 tables. Matches with PRD version
Phys. Rev. D 97, 095026 (2018)
10.1103/PhysRevD.97.095026
IFIC/18-xxx
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the capabilities of the short baseline neutrino program at Fermilab to probe the unitarity of the lepton mixing matrix. We find the sensitivity to be slightly better than the current one. Motivated by the future DUNE experiment, we have also analyzed the potential of an extra liquid Argon near detector in the LBNF beamline. Adding such a near detector to the DUNE setup will substantially improve the current sensitivity on non-unitarity. This would help to remove CP degeneracies due to the new complex phase present in the neutrino mixing matrix. We also study the sensitivity of our proposed setup to light sterile neutrinos for various configurations.
[ { "created": "Tue, 6 Feb 2018 18:57:34 GMT", "version": "v1" }, { "created": "Wed, 30 May 2018 16:22:43 GMT", "version": "v2" } ]
2018-05-31
[ [ "Miranda", "O. G.", "" ], [ "Pasquini", "Pedro", "" ], [ "Tórtola", "M.", "" ], [ "Valle", "J. W. F.", "" ] ]
We study the capabilities of the short baseline neutrino program at Fermilab to probe the unitarity of the lepton mixing matrix. We find the sensitivity to be slightly better than the current one. Motivated by the future DUNE experiment, we have also analyzed the potential of an extra liquid Argon near detector in the LBNF beamline. Adding such a near detector to the DUNE setup will substantially improve the current sensitivity on non-unitarity. This would help to remove CP degeneracies due to the new complex phase present in the neutrino mixing matrix. We also study the sensitivity of our proposed setup to light sterile neutrinos for various configurations.
hep-ph/9912246
Andrei Ivanov
A. Ya. Berdnikov, Ya. A. Berdnikov, A. N. Ivanov, V. F. Kosmach, V. M. Samsonov, and N. I. Troitskaya
On the K^+_- meson production from the quark-gluon plasma phase in ultra-relativistic heavy-ion collisions
16 pages, no figers, Latex
Acta Phys.Slov. 52 (2002) 143-160
null
null
hep-ph
null
An abundance of the strangeness that can be induced in a thermalized quark-gluon plasma (QGP) is considered as a signal of the QGP phase appearing in the intermediate state of ultra-relativistic heavy-ion collisions. As a quantitative characteristic of this signal we take the ratio R_{K^+ K^-} = N_{K^+}/N_{K^-} of the multiplicities of the production of K^+_- mesons. This ratio is evaluated for a thermalized QGP phase of QCD and for the quark-gluon system escaped from the QGP phase. For a thermalized QGP phase the ratio R_{K^+ K^-} has been found as a smooth function of a 3-momentum of the K^+_- mesons and a temperature ranging the values from the region 160 MeV < T <200 MeV. We show that at the temperature T= 175 MeV our prediction for the ratio R_{K^+K^-}(q,T = 175) = 1.80^{+ 0.04}_{-0.18} agrees good with the experimental data of NA49 and NA44 Collaborations on central ultra-relativistic Pb-Pb collisions at 158 GeV per nucleon: R^{\exp}_{K^+K^-} = 1.80\pm 0.10. For the ratio of the K^+ and \pi^+ multiplicities we have obtained the value R_{K^+\pi^+}(q,T = 175) = 0.134\pm 0.014 agreeing good with the experimental data of NA35 Collaboration on the nucleus-nucleus collisions at 200 GeV per nucleon R^{\exp}_{K^+\pi^+} = 0.137\pm 0.008.
[ { "created": "Sun, 5 Dec 1999 18:17:46 GMT", "version": "v1" } ]
2007-05-23
[ [ "Berdnikov", "A. Ya.", "" ], [ "Berdnikov", "Ya. A.", "" ], [ "Ivanov", "A. N.", "" ], [ "Kosmach", "V. F.", "" ], [ "Samsonov", "V. M.", "" ], [ "Troitskaya", "N. I.", "" ] ]
An abundance of the strangeness that can be induced in a thermalized quark-gluon plasma (QGP) is considered as a signal of the QGP phase appearing in the intermediate state of ultra-relativistic heavy-ion collisions. As a quantitative characteristic of this signal we take the ratio R_{K^+ K^-} = N_{K^+}/N_{K^-} of the multiplicities of the production of K^+_- mesons. This ratio is evaluated for a thermalized QGP phase of QCD and for the quark-gluon system escaped from the QGP phase. For a thermalized QGP phase the ratio R_{K^+ K^-} has been found as a smooth function of a 3-momentum of the K^+_- mesons and a temperature ranging the values from the region 160 MeV < T <200 MeV. We show that at the temperature T= 175 MeV our prediction for the ratio R_{K^+K^-}(q,T = 175) = 1.80^{+ 0.04}_{-0.18} agrees good with the experimental data of NA49 and NA44 Collaborations on central ultra-relativistic Pb-Pb collisions at 158 GeV per nucleon: R^{\exp}_{K^+K^-} = 1.80\pm 0.10. For the ratio of the K^+ and \pi^+ multiplicities we have obtained the value R_{K^+\pi^+}(q,T = 175) = 0.134\pm 0.014 agreeing good with the experimental data of NA35 Collaboration on the nucleus-nucleus collisions at 200 GeV per nucleon R^{\exp}_{K^+\pi^+} = 0.137\pm 0.008.
1407.2473
Najmul Haque
Najmul Haque
Some Applications of Hard Thermal Loop Perturbation Theory in Quark Gluon Plasma
248 pages, 54 figures, doctoral thesis submitted and defended at Homi Bhabha National Institute; v2:references added, some typos fixed, few minor revisions
null
null
null
hep-ph hep-lat nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This thesis is mainly devoted to the study of thermodynamics for quantum Chromodynamics. In this thesis I apply hard-thermal-loop perturbation theory, which is a gauge-invariant reorganization of the conventional perturbative expansion for quantum gauge theories to study the thermodynamics of QCD in leading-order, next-to-leading-order and next-to-next-to-leading order at finite temperature and finite chemical potential. I also discuss about various order diagonal and off-diagonal quark number susceptibilities in leading order as well as beyond leading order. For all the observables, I compare our results with available lattice QCD data and we find good agreement. Along with the computation of thermodynamic quantities of hot and dense matter, I also discuss about low mass dilepton rate from hot and dense medium using both perturbative and non-perturbative models and compare them with those from lattice gauge theory and in-medium hadron gas.
[ { "created": "Tue, 8 Jul 2014 15:08:09 GMT", "version": "v1" }, { "created": "Thu, 29 Jan 2015 12:54:35 GMT", "version": "v2" } ]
2015-01-30
[ [ "Haque", "Najmul", "" ] ]
This thesis is mainly devoted to the study of thermodynamics for quantum Chromodynamics. In this thesis I apply hard-thermal-loop perturbation theory, which is a gauge-invariant reorganization of the conventional perturbative expansion for quantum gauge theories to study the thermodynamics of QCD in leading-order, next-to-leading-order and next-to-next-to-leading order at finite temperature and finite chemical potential. I also discuss about various order diagonal and off-diagonal quark number susceptibilities in leading order as well as beyond leading order. For all the observables, I compare our results with available lattice QCD data and we find good agreement. Along with the computation of thermodynamic quantities of hot and dense matter, I also discuss about low mass dilepton rate from hot and dense medium using both perturbative and non-perturbative models and compare them with those from lattice gauge theory and in-medium hadron gas.
2304.04390
Ying-Nan Mao
Kingman Cheung, Ying-nan Mao, Stefano Moretti, Rui Zhang
Testing CP-violation in a Heavy Higgs Sector at CLIC
22 pages, 6 figures
null
null
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
We propose a novel method to test CP-violation in the heavy (pseudo)scalar sector of an extended Higgs model, in which we make simultaneous use of the $HVV$ ($V=W^\pm, Z$) and $Ht\bar{t}$ interactions of a heavy Higgs state $H$. This is possible at the Compact Linear Collider (CLIC) by exploiting $H$ production from Vector-Boson Fusion (VBF) and decay to $t\bar{t}$ pairs. We analyze the distribution of the azimuthal angle between the leptons coming from top and antitop quarks, that would allow one to disentangle the CP nature of such a heavy Higgs state. We also show its implications for the 2-Higgs-Doublet Model (2HDM) with CP-violation.
[ { "created": "Mon, 10 Apr 2023 05:34:09 GMT", "version": "v1" } ]
2023-04-11
[ [ "Cheung", "Kingman", "" ], [ "Mao", "Ying-nan", "" ], [ "Moretti", "Stefano", "" ], [ "Zhang", "Rui", "" ] ]
We propose a novel method to test CP-violation in the heavy (pseudo)scalar sector of an extended Higgs model, in which we make simultaneous use of the $HVV$ ($V=W^\pm, Z$) and $Ht\bar{t}$ interactions of a heavy Higgs state $H$. This is possible at the Compact Linear Collider (CLIC) by exploiting $H$ production from Vector-Boson Fusion (VBF) and decay to $t\bar{t}$ pairs. We analyze the distribution of the azimuthal angle between the leptons coming from top and antitop quarks, that would allow one to disentangle the CP nature of such a heavy Higgs state. We also show its implications for the 2-Higgs-Doublet Model (2HDM) with CP-violation.
hep-ph/0104020
Ugo Giuseppe Aglietti
U. Aglietti
Resummed B -> X_u l nu Decay Distributions to Next-to-Leading Order
LaTex file, 19 pages, 3 postscript figures; minor changes, some typos corrected
Nucl.Phys. B610 (2001) 293-315
10.1016/S0550-3213(01)00316-9
preprint CERN-TH/2001-099
hep-ph
null
We perform factorization of the most general distribution in semileptonic B -> X_u decays and we resum the threshold logarithms to next-to-leading order. From this (triple-differential) distribution, any other distribution is obtained by integration. As an application of our method, we derive simple analytical expressions for a few distributions, resummed to leading approximation. It is shown that the shape function can be directly determined by measuring the distribution in m_X^2/E_X^2, not in m_X^2/m_B^2. We compute the resummed hadron energy spectrum, which has a ``Sudakov shoulder'', and we show how the distribution in the singular region is related to the shape function. We also present an improved formula for the photon spectrum in B->X_s gamma which includes soft-gluon resummation and non-leading operators in the effective hamiltonian. We explicitly show that the same non-perturbative function - namely the shape function - controls the non-perturbative effects in all the distributions in the semi-leptonic and in the rare decay.
[ { "created": "Mon, 2 Apr 2001 15:10:02 GMT", "version": "v1" }, { "created": "Tue, 10 Apr 2001 17:48:50 GMT", "version": "v2" }, { "created": "Wed, 30 May 2001 14:42:57 GMT", "version": "v3" } ]
2009-11-07
[ [ "Aglietti", "U.", "" ] ]
We perform factorization of the most general distribution in semileptonic B -> X_u decays and we resum the threshold logarithms to next-to-leading order. From this (triple-differential) distribution, any other distribution is obtained by integration. As an application of our method, we derive simple analytical expressions for a few distributions, resummed to leading approximation. It is shown that the shape function can be directly determined by measuring the distribution in m_X^2/E_X^2, not in m_X^2/m_B^2. We compute the resummed hadron energy spectrum, which has a ``Sudakov shoulder'', and we show how the distribution in the singular region is related to the shape function. We also present an improved formula for the photon spectrum in B->X_s gamma which includes soft-gluon resummation and non-leading operators in the effective hamiltonian. We explicitly show that the same non-perturbative function - namely the shape function - controls the non-perturbative effects in all the distributions in the semi-leptonic and in the rare decay.
hep-ph/0204205
Nils Tornqvist
Frank E. Close (Oxford) and Nils A. Tornqvist (Helsinki)
Scalar mesons above and below 1 GeV
34 pages in Latex, minor improvements in sec 6
J.Phys.G28:R249-R267,2002
10.1088/0954-3899/28/10/201
null
hep-ph nucl-th
null
We show that two nonets and a glueball provide a consistent description of data on scalar mesons below 1.7 GeV. Above 1 GeV the states form a conventional (q bar q) nonet mixed with the glueball of lattice QCD. Below 1 GeV the states also form a nonet, as implied by the attractive forces of QCD, but of more complicated nature. Near the center they are 4 quark states of the Jaffe type in S-wave, with some (q bar q) in P-wave, but further out they rearrange in colour to two colourless (q bar q) pairs and finally as meson-meson states. A simple effective chiral model for such a system with two scalar nonets can be made involving two coupled linear sigma models. One of these could be looked upon as the Higgs sector of nonpertubative QCD.
[ { "created": "Wed, 17 Apr 2002 14:55:12 GMT", "version": "v1" }, { "created": "Thu, 18 Apr 2002 13:10:36 GMT", "version": "v2" }, { "created": "Wed, 19 Jun 2002 09:18:18 GMT", "version": "v3" } ]
2011-08-17
[ [ "Close", "Frank E.", "", "Oxford" ], [ "Tornqvist", "Nils A.", "", "Helsinki" ] ]
We show that two nonets and a glueball provide a consistent description of data on scalar mesons below 1.7 GeV. Above 1 GeV the states form a conventional (q bar q) nonet mixed with the glueball of lattice QCD. Below 1 GeV the states also form a nonet, as implied by the attractive forces of QCD, but of more complicated nature. Near the center they are 4 quark states of the Jaffe type in S-wave, with some (q bar q) in P-wave, but further out they rearrange in colour to two colourless (q bar q) pairs and finally as meson-meson states. A simple effective chiral model for such a system with two scalar nonets can be made involving two coupled linear sigma models. One of these could be looked upon as the Higgs sector of nonpertubative QCD.
hep-ph/0010072
Dmitri S. Kourashev
Dmitri S. Kourashev
Exact analytic two-loop expressions for some QCD observables in the time-like region
8 pages
null
null
null
hep-ph
null
The author of this work have got explicit expressions for the timelike region at Next-to-Leading-Order (NLO) as for the coupling function so for QCD observables. These expressions were compared with approximate ones obtained in terms of "double logarithms". Next-Next-to-Leading-Order (NNLO) Pade approximation was also discussed. In this paper some particular role of NLO was emphasised. It is related with the possibility to express any multi-loop expressions in terms of the two-loop ones. Thus we can use NLO functions as a basis of some functional expansion, where higher loop terms incorporation affects the expansion coefficients only.
[ { "created": "Sun, 8 Oct 2000 18:58:36 GMT", "version": "v1" }, { "created": "Wed, 10 Jan 2001 13:55:06 GMT", "version": "v2" } ]
2007-05-23
[ [ "Kourashev", "Dmitri S.", "" ] ]
The author of this work have got explicit expressions for the timelike region at Next-to-Leading-Order (NLO) as for the coupling function so for QCD observables. These expressions were compared with approximate ones obtained in terms of "double logarithms". Next-Next-to-Leading-Order (NNLO) Pade approximation was also discussed. In this paper some particular role of NLO was emphasised. It is related with the possibility to express any multi-loop expressions in terms of the two-loop ones. Thus we can use NLO functions as a basis of some functional expansion, where higher loop terms incorporation affects the expansion coefficients only.
hep-ph/9705213
null
F. Buccella, G. Mangano and L. Rosa
Neutrino masses and baryogenesis in SO(10) unified theories
Latex 16 pages, 1 ps figure. Appeared in Proceedings of seventh International Workshop on Neutrino Telescopes, Venezia February 27 - March 1 1996, Editor M. Baldo Ceolin
null
null
null
hep-ph
null
We report on some phenomenological implications of a class of unified models based on SO(10) gauge group, with intermediate symmetry group containing SU(2)_R. Interesting predictions for neutrino masses are discussed, which are relevant both for solar neutrino and dark matter problems, as well as a model for the formation of the baryon asymmetry of the universe required by primordial nucleosynthesis.
[ { "created": "Fri, 2 May 1997 08:47:38 GMT", "version": "v1" } ]
2007-05-23
[ [ "Buccella", "F.", "" ], [ "Mangano", "G.", "" ], [ "Rosa", "L.", "" ] ]
We report on some phenomenological implications of a class of unified models based on SO(10) gauge group, with intermediate symmetry group containing SU(2)_R. Interesting predictions for neutrino masses are discussed, which are relevant both for solar neutrino and dark matter problems, as well as a model for the formation of the baryon asymmetry of the universe required by primordial nucleosynthesis.
1801.08947
Sebastian Trojanowski
Felix Kling, Sebastian Trojanowski
Heavy Neutral Leptons at FASER
24 pages, 9 figures; matches to the published version
Phys. Rev. D 97, 095016 (2018)
10.1103/PhysRevD.97.095016
UCI-TR-2017-18
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the prospects for discovering heavy neutral leptons at ForwArd Search ExpeRiment (FASER), the newly proposed detector at the LHC. Previous studies showed that a relatively small detector with ~10 m length and ~1 m cross sectional area can probe large unconstrained parts of parameter space for dark photons and dark Higgs bosons. In this work we show that FASER will also be sensitive to heavy neutral leptons that have mixing angles with the active neutrinos that are up to an order of magnitude lower than current bounds. In particular, this is true for heavy neutral leptons produced dominantly in $B$-meson decays, in which case FASER's discovery potential is comparable to the proposed SHiP detector. We also illustrate how the search for heavy neutral leptons at FASER will be complementary to ongoing searches in high-$p_T$ experiments at the LHC and can shed light on the nature of dark matter and the process of baryogenesis in the early Universe.
[ { "created": "Fri, 26 Jan 2018 19:00:36 GMT", "version": "v1" }, { "created": "Thu, 24 May 2018 22:02:31 GMT", "version": "v2" } ]
2018-05-28
[ [ "Kling", "Felix", "" ], [ "Trojanowski", "Sebastian", "" ] ]
We study the prospects for discovering heavy neutral leptons at ForwArd Search ExpeRiment (FASER), the newly proposed detector at the LHC. Previous studies showed that a relatively small detector with ~10 m length and ~1 m cross sectional area can probe large unconstrained parts of parameter space for dark photons and dark Higgs bosons. In this work we show that FASER will also be sensitive to heavy neutral leptons that have mixing angles with the active neutrinos that are up to an order of magnitude lower than current bounds. In particular, this is true for heavy neutral leptons produced dominantly in $B$-meson decays, in which case FASER's discovery potential is comparable to the proposed SHiP detector. We also illustrate how the search for heavy neutral leptons at FASER will be complementary to ongoing searches in high-$p_T$ experiments at the LHC and can shed light on the nature of dark matter and the process of baryogenesis in the early Universe.
2211.09661
Eugenio Megias
Eugenio Megias, Mariano Quiros
Physics of warped dimensions: discrete and continuous spectra
8 pages, 3 figures. Talk given by E.Megias at the XVth Quark Confinement and the Hadron Spectrum Conference, Stavanger, Norway, 1 - 6 August 2022
null
10.1051/epjconf/202225806008
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Using two different warped five-dimensional (5D) models with two branes along the extra dimension, we study the Green's functions and the spectral properties of some of the fields propagating in the bulk. While the first model has a discrete spectrum of Kaluza-Klein (KK) modes, the second one has a continuous spectrum above a mass gap. We also study the positivity of the spectral functions, as well as the coupling of the graviton and the radion with SM matter fields.
[ { "created": "Thu, 17 Nov 2022 17:00:13 GMT", "version": "v1" } ]
2022-11-23
[ [ "Megias", "Eugenio", "" ], [ "Quiros", "Mariano", "" ] ]
Using two different warped five-dimensional (5D) models with two branes along the extra dimension, we study the Green's functions and the spectral properties of some of the fields propagating in the bulk. While the first model has a discrete spectrum of Kaluza-Klein (KK) modes, the second one has a continuous spectrum above a mass gap. We also study the positivity of the spectral functions, as well as the coupling of the graviton and the radion with SM matter fields.
0801.4374
Oscar Cata
O. Cata (LBNL) and V. Mateu (IFIC)
Novel patterns for vector mesons from the large-Nc limit
7 pages
Phys.Rev.D77:116009,2008
10.1103/PhysRevD.77.116009
null
hep-ph
null
We report on a relation between the decay constants of \rho-like J^{PC}=1^{--} vector mesons, which arises solely from the perturbative analysis of the VV, TT and VT correlators at order \alpha_s^0 in the large-N_c limit. We find f_{V}^T/f_{V}=1/\sqrt{2} for highly excited states together with a pattern of alternation in sign. Quite remarkably, recent lattice determinations reported f_{\rho}^T/f_{\rho}=0.72(2), in excellent agreement with our large-N_c result. This seems to suggest a pattern like f_{Vn}^T/f_{Vn}=(-1)^n/\sqrt{2} for the whole (1^{--}) states. In order to test this conjecture in real QCD we construct a set of spectral sum rules, which turn out to comply nicely with this scenario.
[ { "created": "Mon, 28 Jan 2008 21:12:53 GMT", "version": "v1" } ]
2008-11-26
[ [ "Cata", "O.", "", "LBNL" ], [ "Mateu", "V.", "", "IFIC" ] ]
We report on a relation between the decay constants of \rho-like J^{PC}=1^{--} vector mesons, which arises solely from the perturbative analysis of the VV, TT and VT correlators at order \alpha_s^0 in the large-N_c limit. We find f_{V}^T/f_{V}=1/\sqrt{2} for highly excited states together with a pattern of alternation in sign. Quite remarkably, recent lattice determinations reported f_{\rho}^T/f_{\rho}=0.72(2), in excellent agreement with our large-N_c result. This seems to suggest a pattern like f_{Vn}^T/f_{Vn}=(-1)^n/\sqrt{2} for the whole (1^{--}) states. In order to test this conjecture in real QCD we construct a set of spectral sum rules, which turn out to comply nicely with this scenario.
1811.09482
Arie Bodek
Arie Bodek, Tejin Cai
Optical Potential and Removal Energies in Lepton Nucleus Scattering
3 pages 3 Figures, Presented at the 20th International Workshop on Neutrinos (NuFact2018) 12-18 August 2018, Blacksburg, Virginia
null
null
PoS(NuFACT2018)094
hep-ph hep-ex nucl-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We summarize some of the results presented in arXiv:1801.07975 [nucl-th]\cite{FSIpaper}(to be published in EPJC in 2018) on modeling electron and neutrino QE scattering on a variety of nuclei within the impulse approximation. We find that with three parameters we can describe the final state lepton energy for all of available electron QE data on Lithium, Carbon+Oxygen, Aluminum, Calcium+Argon, Iron and Lead+Gold. The first parameter, the removal energy $\epsilon^{P,N}$ is extracted from exclusive ee$^{\prime}$p spectral function data. The second parameter $V_{eff}$, which accounts for the interaction of final state leptons and protons with the Coulomb potential of the nucleus, is available from published comparisons of inclusive QE electron and positron cross section. We extract the third parameter $U_{FSI}(\vec {q}_3^2)$, which accounts for the interaction of the final state nucleon with the optical potential of the spectator nucleus (FSI), by fitting all available inclusive QE cross sections on nuclear targets. Here $q_3$ is the three momentum transfer. With these three parameters we can model the energy of final state electrons and nucleons for all available electron QE scattering data. At present the uncertainty in the value of the removal energy parameters is a the largest source of systematic error in the extraction of the neutrino oscillation parameter $\Delta{m}^2$. The use of the updated parameters in neutrino Monte Carlo generators reduces the systematic uncertainty in the combined removal energy (with FSI corrections) from $\pm$ 20 MeV to $\pm$ 5 MeV. In this short contribution we only summarize the results for Carbon+Oxygen and Calcium+Argon
[ { "created": "Fri, 23 Nov 2018 14:06:08 GMT", "version": "v1" } ]
2020-04-02
[ [ "Bodek", "Arie", "" ], [ "Cai", "Tejin", "" ] ]
We summarize some of the results presented in arXiv:1801.07975 [nucl-th]\cite{FSIpaper}(to be published in EPJC in 2018) on modeling electron and neutrino QE scattering on a variety of nuclei within the impulse approximation. We find that with three parameters we can describe the final state lepton energy for all of available electron QE data on Lithium, Carbon+Oxygen, Aluminum, Calcium+Argon, Iron and Lead+Gold. The first parameter, the removal energy $\epsilon^{P,N}$ is extracted from exclusive ee$^{\prime}$p spectral function data. The second parameter $V_{eff}$, which accounts for the interaction of final state leptons and protons with the Coulomb potential of the nucleus, is available from published comparisons of inclusive QE electron and positron cross section. We extract the third parameter $U_{FSI}(\vec {q}_3^2)$, which accounts for the interaction of the final state nucleon with the optical potential of the spectator nucleus (FSI), by fitting all available inclusive QE cross sections on nuclear targets. Here $q_3$ is the three momentum transfer. With these three parameters we can model the energy of final state electrons and nucleons for all available electron QE scattering data. At present the uncertainty in the value of the removal energy parameters is a the largest source of systematic error in the extraction of the neutrino oscillation parameter $\Delta{m}^2$. The use of the updated parameters in neutrino Monte Carlo generators reduces the systematic uncertainty in the combined removal energy (with FSI corrections) from $\pm$ 20 MeV to $\pm$ 5 MeV. In this short contribution we only summarize the results for Carbon+Oxygen and Calcium+Argon
2310.04136
Snehit Panghal
Snehit Panghal and Biswarup Mukhopadhyaya
Loop-induced Higgs decays in two Higgs doublet scenarios: some observations
16 pages, 11 figures
null
null
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
We study the decay of three neutral Higgs bosons into {\gamma}{\gamma} and Z{\gamma} in the four major types of two Higgs doublet models with CP conserved. Particular focus is made on the possibility of the width of the latter decay dominating over the former. For the 125-GeV scalar, such a possibility is mostly excluded when one imposes all theoretical and experimental constraints, other than the Higgs data at the Large Hadron Collider. For the other CP-even neutral scalar, there remain regions in each kind of model where the Z{\gamma} mode dominates. For the CP-odd state, this possibility is restricted to only the models of Types II and Y, in certain regions of the parameter space.
[ { "created": "Fri, 6 Oct 2023 10:19:45 GMT", "version": "v1" } ]
2023-10-09
[ [ "Panghal", "Snehit", "" ], [ "Mukhopadhyaya", "Biswarup", "" ] ]
We study the decay of three neutral Higgs bosons into {\gamma}{\gamma} and Z{\gamma} in the four major types of two Higgs doublet models with CP conserved. Particular focus is made on the possibility of the width of the latter decay dominating over the former. For the 125-GeV scalar, such a possibility is mostly excluded when one imposes all theoretical and experimental constraints, other than the Higgs data at the Large Hadron Collider. For the other CP-even neutral scalar, there remain regions in each kind of model where the Z{\gamma} mode dominates. For the CP-odd state, this possibility is restricted to only the models of Types II and Y, in certain regions of the parameter space.
hep-ph/0612008
Xiang Liu
Shu-Min Zhao, Xiang Liu and Shuang-Jiu Li
Study on $B_s\to D_{sJ}(2317,2460)l\bar{\nu}$ Semileptonic Decays in the CQM Model
5 pages, 3 figure, 3 tables, add more discussions, correct typos. The final version to appear at EPJC
Eur.Phys.J.C51:601-606,2007
10.1140/epjc/s10052-007-0322-7
null
hep-ph hep-ex
null
Assuming $D^*_{sJ}(2317)$ and $D_{sJ}(2460)$ to be the $(0^+,1^+)$ chiral partners of regular $D_{s}(1968)$ and $D^{*}_{s}(2112)$, we calculate the semileptonic decays of $B_s$ to $D_s(1968)$, $D^*_s(2112)$, $D_{sJ}^{*}(2317)$, $D_{sJ}(2460)$ in terms of the Constituent Quark Meson (CQM) model. The large branching ratios of the semileptonic decays of $B_s$ to $D_{sJ}^{*}(2317)$ and $D_{sJ}(2460)$ indicate that those two semileptonic decays should be seen in future experiments.
[ { "created": "Fri, 1 Dec 2006 09:10:49 GMT", "version": "v1" }, { "created": "Sun, 3 Dec 2006 04:28:56 GMT", "version": "v2" }, { "created": "Tue, 5 Dec 2006 02:24:31 GMT", "version": "v3" }, { "created": "Tue, 8 May 2007 02:44:13 GMT", "version": "v4" } ]
2008-11-26
[ [ "Zhao", "Shu-Min", "" ], [ "Liu", "Xiang", "" ], [ "Li", "Shuang-Jiu", "" ] ]
Assuming $D^*_{sJ}(2317)$ and $D_{sJ}(2460)$ to be the $(0^+,1^+)$ chiral partners of regular $D_{s}(1968)$ and $D^{*}_{s}(2112)$, we calculate the semileptonic decays of $B_s$ to $D_s(1968)$, $D^*_s(2112)$, $D_{sJ}^{*}(2317)$, $D_{sJ}(2460)$ in terms of the Constituent Quark Meson (CQM) model. The large branching ratios of the semileptonic decays of $B_s$ to $D_{sJ}^{*}(2317)$ and $D_{sJ}(2460)$ indicate that those two semileptonic decays should be seen in future experiments.
1107.4087
Elena Accomando
Elena Accomando, Diego Becciolini, Stefania De Curtis, Daniele Dominici, Luca Fedeli
W' production at the LHC in the 4-site Higgsless model
28 pages, references added
null
10.1103/PhysRevD.84.115014
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the phenomenology of the 4-site Higgsless model, based on the $SU(2)_L\times SU(2)_1\times SU(2)_2\times U(1)_Y$ gauge symmetry, at present colliders. The model predicts the existence of two neutral and four charged extra gauge bosons, Z1,Z2,W1,W2. In this paper, we focus on the charged gauge sector. We first derive limits on W1,W2-boson masses and couplings to SM fermions from direct searches at the Tevatron. We then estimate at the 7 TeV LHC the exclusion limits with the actual L=1 fb-1 and the discovery potential with the expected L=10 fb-1. In contrast to the minimal (or 3-site) Higgsless model which predicts almost fermiophobic extra gauge bosons, the next-to-minimal (or 4-site) Higgsless model recovers sizeable W1,W2-boson couplings to ordinary matter, expressing the non-fermiophobic multiresonance inner nature of extra-dimensional theories. Owing to this feature, we find that in one year from now the new heavy gauge bosons, W1 and W2, could be discovered in the final state with an electron and large missing transverse energy at the 7 TeV LHC for W1,W2-boson masses in the TeV region, depending on model parameters.
[ { "created": "Wed, 20 Jul 2011 19:51:39 GMT", "version": "v1" }, { "created": "Tue, 6 Sep 2011 16:36:58 GMT", "version": "v2" } ]
2013-05-29
[ [ "Accomando", "Elena", "" ], [ "Becciolini", "Diego", "" ], [ "De Curtis", "Stefania", "" ], [ "Dominici", "Daniele", "" ], [ "Fedeli", "Luca", "" ] ]
We study the phenomenology of the 4-site Higgsless model, based on the $SU(2)_L\times SU(2)_1\times SU(2)_2\times U(1)_Y$ gauge symmetry, at present colliders. The model predicts the existence of two neutral and four charged extra gauge bosons, Z1,Z2,W1,W2. In this paper, we focus on the charged gauge sector. We first derive limits on W1,W2-boson masses and couplings to SM fermions from direct searches at the Tevatron. We then estimate at the 7 TeV LHC the exclusion limits with the actual L=1 fb-1 and the discovery potential with the expected L=10 fb-1. In contrast to the minimal (or 3-site) Higgsless model which predicts almost fermiophobic extra gauge bosons, the next-to-minimal (or 4-site) Higgsless model recovers sizeable W1,W2-boson couplings to ordinary matter, expressing the non-fermiophobic multiresonance inner nature of extra-dimensional theories. Owing to this feature, we find that in one year from now the new heavy gauge bosons, W1 and W2, could be discovered in the final state with an electron and large missing transverse energy at the 7 TeV LHC for W1,W2-boson masses in the TeV region, depending on model parameters.
2112.12771
Anil Thapa
K.S. Babu, Sudip Jana, Anil Thapa
Vector Boson Dark Matter From Trinification
25 pages + references, 8 figures, added section 2.2 and new references
null
10.1007/JHEP02(2022)051
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
We show how trinification models based on the gauge group $SU(3)_C \times SU(3)_L \times SU(3)_R$ realized near the TeV scale can provide naturally a variety of dark matter (DM) candidates. These models contain a discrete $T$ parity which may remain unbroken even after spontaneous symmetry breaking. The lightest $T$-odd particle, which could be a fermion, a scalar, or a gauge boson, can constitute the dark matter of the universe. This framework naturally admits a doublet-singlet fermionic DM, a singlet scalar DM, or a vector boson DM. Here we develop the vector boson DM scenario wherein the DM couples off-diagonally with the usual fermions and vector-like fermions present in the theory. We show consistency of this framework with dark matter relic abundance and direct detection limits as well as LHC constraints. We derive upper limits of 900 GeV on the vector gauge boson DM mass and 4.5 TeV on the vector-like quarks and lepton masses. We also show the consistency of spontaneous gauge symmetry breaking down to Standard Model times an extra $U(1)$ while preserving the $T$-parity.
[ { "created": "Thu, 23 Dec 2021 18:48:02 GMT", "version": "v1" }, { "created": "Tue, 4 Jan 2022 18:11:57 GMT", "version": "v2" } ]
2022-03-02
[ [ "Babu", "K. S.", "" ], [ "Jana", "Sudip", "" ], [ "Thapa", "Anil", "" ] ]
We show how trinification models based on the gauge group $SU(3)_C \times SU(3)_L \times SU(3)_R$ realized near the TeV scale can provide naturally a variety of dark matter (DM) candidates. These models contain a discrete $T$ parity which may remain unbroken even after spontaneous symmetry breaking. The lightest $T$-odd particle, which could be a fermion, a scalar, or a gauge boson, can constitute the dark matter of the universe. This framework naturally admits a doublet-singlet fermionic DM, a singlet scalar DM, or a vector boson DM. Here we develop the vector boson DM scenario wherein the DM couples off-diagonally with the usual fermions and vector-like fermions present in the theory. We show consistency of this framework with dark matter relic abundance and direct detection limits as well as LHC constraints. We derive upper limits of 900 GeV on the vector gauge boson DM mass and 4.5 TeV on the vector-like quarks and lepton masses. We also show the consistency of spontaneous gauge symmetry breaking down to Standard Model times an extra $U(1)$ while preserving the $T$-parity.
2104.03691
Douglas H. J. Jacob
Peter Athron, Csaba Bal\'azs, Douglas HJ Jacob, Wojciech Kotlarski, Dominik St\"ockinger, Hyejung St\"ockinger-Kim
New physics explanations of $a_\mu$ in light of the FNAL muon $g-2$ measurement
106 pages, 20 figures, 5 tables; v2 added references, minor corrections to table 2 and improvements to Figs 2,3 and 4; v3 as published in JHEP
null
10.1007/JHEP09(2021)080
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Fermilab Muon $g-2$ experiment recently reported its first measurement of the anomalous magnetic moment $a_\mu^{\textrm{FNAL}}$, which is in full agreement with the previous BNL measurement and pushes the world average deviation $\Delta a_\mu^{2021}$ from the Standard Model to a significance of $4.2\sigma$. Here we provide an extensive survey of its impact on beyond the Standard Model physics. We use state-of-the-art calculations and a sophisticated set of tools to make predictions for $a_\mu$, dark matter and LHC searches in a wide range of simple models with up to three new fields, that represent some of the few ways that large $\Delta a_\mu$ can be explained. In addition for the particularly well motivated Minimal Supersymmetric Standard Model, we exhaustively cover the scenarios where large $\Delta a_\mu$ can be explained while simultaneously satisfying all relevant data from other experiments. Generally, the $\Delta a_\mu$ result can only be explained by rather small masses and/or large couplings and enhanced chirality flips, which can lead to conflicts with limits from LHC and dark matter experiments. Our results show that the new measurement excludes a large number of models and provides crucial constraints on others. Two-Higgs doublet and leptoquark models provide viable explanations of $a_\mu$ only in specific versions and in specific parameter ranges. Among all models with up to three fields, only models with chirality enhancements can accommodate $a_\mu$ and dark matter simultaneously. The MSSM can simultaneously explain $a_\mu$ and dark matter for Bino-like LSP in several coannihilation regions. Allowing under abundance of the dark matter relic density, the Higgsino- and particularly Wino-like LSP scenarios become promising explanations of the $a_\mu$ result.
[ { "created": "Thu, 8 Apr 2021 11:24:04 GMT", "version": "v1" }, { "created": "Tue, 20 Apr 2021 06:35:03 GMT", "version": "v2" }, { "created": "Fri, 8 Oct 2021 05:24:24 GMT", "version": "v3" } ]
2021-10-11
[ [ "Athron", "Peter", "" ], [ "Balázs", "Csaba", "" ], [ "Jacob", "Douglas HJ", "" ], [ "Kotlarski", "Wojciech", "" ], [ "Stöckinger", "Dominik", "" ], [ "Stöckinger-Kim", "Hyejung", "" ] ]
The Fermilab Muon $g-2$ experiment recently reported its first measurement of the anomalous magnetic moment $a_\mu^{\textrm{FNAL}}$, which is in full agreement with the previous BNL measurement and pushes the world average deviation $\Delta a_\mu^{2021}$ from the Standard Model to a significance of $4.2\sigma$. Here we provide an extensive survey of its impact on beyond the Standard Model physics. We use state-of-the-art calculations and a sophisticated set of tools to make predictions for $a_\mu$, dark matter and LHC searches in a wide range of simple models with up to three new fields, that represent some of the few ways that large $\Delta a_\mu$ can be explained. In addition for the particularly well motivated Minimal Supersymmetric Standard Model, we exhaustively cover the scenarios where large $\Delta a_\mu$ can be explained while simultaneously satisfying all relevant data from other experiments. Generally, the $\Delta a_\mu$ result can only be explained by rather small masses and/or large couplings and enhanced chirality flips, which can lead to conflicts with limits from LHC and dark matter experiments. Our results show that the new measurement excludes a large number of models and provides crucial constraints on others. Two-Higgs doublet and leptoquark models provide viable explanations of $a_\mu$ only in specific versions and in specific parameter ranges. Among all models with up to three fields, only models with chirality enhancements can accommodate $a_\mu$ and dark matter simultaneously. The MSSM can simultaneously explain $a_\mu$ and dark matter for Bino-like LSP in several coannihilation regions. Allowing under abundance of the dark matter relic density, the Higgsino- and particularly Wino-like LSP scenarios become promising explanations of the $a_\mu$ result.
1910.10928
Kazem Bitaghsir Fadafan
Alexander Belyaev, Kazem Bitaghsir Fadafan, Nick Evans, Mansoureh Gholamzadeh
Any Room Left for Technicolor? Holographic Studies of NJL Assisted Technicolour
13 pages, 6 figures, 9 tables
Phys. Rev. D 101, 086013 (2020)
10.1103/PhysRevD.101.086013
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We use a holographic description of technicolor dynamics to study gauge theories that only break chiral symmetry when aided by a strong four fermion interaction. These Nambu-Jona-Lasinio (NJL) assisted technicolor models provide examples of different dynamics from walking technicolor which can, by tuning, generate a light higgs like $\sigma$ meson. We compute the vector meson ($\rho$) and axial vector meson (A) spectrum for a variety of models with techni-quarks in the fundamental representation, enlarging the available parameter space over a previous analysis of walking theories. These predictions determine the parameter space of a low energy effective description where LHC constraints from dilepton channels have already been applied. Many of the models with low numbers of electroweak doublets still lie beyond current constraints and motivate exploration of new signatures beyond dilepton for LHC and a 100 TeV proton collider.
[ { "created": "Thu, 24 Oct 2019 06:13:07 GMT", "version": "v1" } ]
2020-04-15
[ [ "Belyaev", "Alexander", "" ], [ "Fadafan", "Kazem Bitaghsir", "" ], [ "Evans", "Nick", "" ], [ "Gholamzadeh", "Mansoureh", "" ] ]
We use a holographic description of technicolor dynamics to study gauge theories that only break chiral symmetry when aided by a strong four fermion interaction. These Nambu-Jona-Lasinio (NJL) assisted technicolor models provide examples of different dynamics from walking technicolor which can, by tuning, generate a light higgs like $\sigma$ meson. We compute the vector meson ($\rho$) and axial vector meson (A) spectrum for a variety of models with techni-quarks in the fundamental representation, enlarging the available parameter space over a previous analysis of walking theories. These predictions determine the parameter space of a low energy effective description where LHC constraints from dilepton channels have already been applied. Many of the models with low numbers of electroweak doublets still lie beyond current constraints and motivate exploration of new signatures beyond dilepton for LHC and a 100 TeV proton collider.
2101.11808
Manfred Kraus
F. Febres Cordero, M. Kraus and L. Reina
Top-quark pair production in association with a $W^\pm$ gauge boson in the POWHEG-BOX
52 pages and 36 beautiful plots, matches published version
Phys. Rev. D 103, 094014 (2021)
10.1103/PhysRevD.103.094014
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a new Monte Carlo event generator for the production of a top-quark pair in association with a $W^\pm$ boson at hadron colliders in the POWHEG-BOX framework. We consider the next-to-leading-order QCD corrections to the $pp\to t\bar{t} W^\pm$ cross section, corresponding to the $\mathcal{O}(\alpha_s^3\alpha)$ and $\mathcal{O}(\alpha_s\alpha^3)$ terms in the perturbative expansion of the parton-level cross section, and model the decays of $W$ and top quarks at leading order retaining spin correlations. The fixed-order QCD calculation is further interfaced with the Pythia8 parton-shower event generator via the POWHEG method as implemented in the POWHEG-BOX. The corresponding code is now part of the public repository of the POWHEG-BOX. We perform a comparison of different event generators for both the case of inclusive production and the case of the two same-sign leptons signature at the Large Hadron Collider operating at a center-of-mass energy of $13$ TeV. We investigate theoretical uncertainties in the modelling of the fiducial volume stemming from missing higher-order corrections, the different parton shower matching schemes, and the modelling of decays. We find that the subleading contribution at $\mathcal{O}(\alpha_s\alpha^3)$ is particularly sensitive to differences in the matching scheme and higher-order parton shower effects. We observe that in particular jet observables can differ quite visibly although these differences play only a subordinate role in the description of physical observables once all contributions are combined.
[ { "created": "Thu, 28 Jan 2021 04:02:14 GMT", "version": "v1" }, { "created": "Sun, 16 May 2021 17:11:39 GMT", "version": "v2" } ]
2021-05-19
[ [ "Cordero", "F. Febres", "" ], [ "Kraus", "M.", "" ], [ "Reina", "L.", "" ] ]
We present a new Monte Carlo event generator for the production of a top-quark pair in association with a $W^\pm$ boson at hadron colliders in the POWHEG-BOX framework. We consider the next-to-leading-order QCD corrections to the $pp\to t\bar{t} W^\pm$ cross section, corresponding to the $\mathcal{O}(\alpha_s^3\alpha)$ and $\mathcal{O}(\alpha_s\alpha^3)$ terms in the perturbative expansion of the parton-level cross section, and model the decays of $W$ and top quarks at leading order retaining spin correlations. The fixed-order QCD calculation is further interfaced with the Pythia8 parton-shower event generator via the POWHEG method as implemented in the POWHEG-BOX. The corresponding code is now part of the public repository of the POWHEG-BOX. We perform a comparison of different event generators for both the case of inclusive production and the case of the two same-sign leptons signature at the Large Hadron Collider operating at a center-of-mass energy of $13$ TeV. We investigate theoretical uncertainties in the modelling of the fiducial volume stemming from missing higher-order corrections, the different parton shower matching schemes, and the modelling of decays. We find that the subleading contribution at $\mathcal{O}(\alpha_s\alpha^3)$ is particularly sensitive to differences in the matching scheme and higher-order parton shower effects. We observe that in particular jet observables can differ quite visibly although these differences play only a subordinate role in the description of physical observables once all contributions are combined.
hep-ph/9403209
Michael Bergmann
M. Bergmann and N. G. Stefanis
Heterotic Approach to the Nucleon Distribution Amplitude
11 pages, report: RUB-TPII-93/36
Phys.Lett. B325 (1994) 183-189
10.1016/0370-2693(94)90090-6
null
hep-ph
null
We give an in-depth analysis of the determination procedure of the recently proposed heterotic nucleon distribution amplitude which hybridizes the best features of the Chernyak-Ogloblin-Zhitnitsky and the Gari-Stefanis models. With respect to the QCD sum-rule constraints, optimized versions of these amplitudes are derived in terms of which a "hybridity" angle can be introduced to systematically classify all models.
[ { "created": "Wed, 2 Mar 1994 12:54:40 GMT", "version": "v1" } ]
2009-10-28
[ [ "Bergmann", "M.", "" ], [ "Stefanis", "N. G.", "" ] ]
We give an in-depth analysis of the determination procedure of the recently proposed heterotic nucleon distribution amplitude which hybridizes the best features of the Chernyak-Ogloblin-Zhitnitsky and the Gari-Stefanis models. With respect to the QCD sum-rule constraints, optimized versions of these amplitudes are derived in terms of which a "hybridity" angle can be introduced to systematically classify all models.
hep-ph/9604337
Chi-Sing Lam
C.S. Lam (McGill University) and K.F. Liu (University of Kentucky)
A Multiple Commutator Formula for the Sum of Feynman Diagrams
uu-encoded latex file with two postscript figures
Nucl.Phys. B483 (1997) 514-530
10.1016/S0550-3213(96)00548-2
McGill/96-12
hep-ph
null
In the presence of a large parameter, such as mass or energy, leading behavior of individual Feynman diagrams often get cancelled in the sum. This is known to happen in large-$N_c$ QCD in the presence of a baryon, and also in the case of high-energy electron-electron as well as quark-quark scatterings. We present an exact combinatorial formula, involving multiple commutators of the vertices, which can be used to compute such cancellations. It is a non-abelian generalization of the eikonal formula, and will be applied in subsequent publications to study the consistency of large-$N_c$ QCD involving baryons, as well as high-energy quark-quark scattering in ordinary QCD.
[ { "created": "Tue, 16 Apr 1996 21:31:29 GMT", "version": "v1" } ]
2009-10-28
[ [ "Lam", "C. S.", "", "McGill University" ], [ "Liu", "K. F.", "", "University of Kentucky" ] ]
In the presence of a large parameter, such as mass or energy, leading behavior of individual Feynman diagrams often get cancelled in the sum. This is known to happen in large-$N_c$ QCD in the presence of a baryon, and also in the case of high-energy electron-electron as well as quark-quark scatterings. We present an exact combinatorial formula, involving multiple commutators of the vertices, which can be used to compute such cancellations. It is a non-abelian generalization of the eikonal formula, and will be applied in subsequent publications to study the consistency of large-$N_c$ QCD involving baryons, as well as high-energy quark-quark scattering in ordinary QCD.
hep-ph/0009113
Youichi Yamada
Y. Yamada, H. Eberl, K. Hidaka, S. Kraml, W. Majerotto
Improved SUSY QCD corrections to Higgs boson decays into quarks and squarks
3 pages, 2 figures, Talk given at ICHEP 2000, Osaka, Japan, 27 July - 2 August 2000
null
null
TU-602
hep-ph
null
The O(alpha_s) SUSY QCD corrections to the decays of the MSSM Higgs bosons into bottom quarks and squarks can be very large for large tan beta in the on--shell renormalization scheme. We improve the calculation by a careful choice of the tree-level Higgs boson couplings in terms of running parameters of quarks and squarks.
[ { "created": "Mon, 11 Sep 2000 03:18:28 GMT", "version": "v1" } ]
2007-05-23
[ [ "Yamada", "Y.", "" ], [ "Eberl", "H.", "" ], [ "Hidaka", "K.", "" ], [ "Kraml", "S.", "" ], [ "Majerotto", "W.", "" ] ]
The O(alpha_s) SUSY QCD corrections to the decays of the MSSM Higgs bosons into bottom quarks and squarks can be very large for large tan beta in the on--shell renormalization scheme. We improve the calculation by a careful choice of the tree-level Higgs boson couplings in terms of running parameters of quarks and squarks.
hep-ph/9804448
Alexandr Andrianov
A. A. Andrianov (St.Petersburg U. and U. of Barcelona) and R. Soldati (U. of Bologna)
Patterns of Lorentz symmetry breaking in QED by CPT-odd interaction
9 pages, LaTeX, version to appear in Phys.Lett.B
Phys.Lett. B435 (1998) 449-452
10.1016/S0370-2693(98)00823-5
DFUB-98/8; UB-ECM-PF-98/10
hep-ph astro-ph
null
A tiny Lorentz symmetry breaking can be mediated in Electrodynamics by means of the Chern-Simons (CS) interaction polarized along a constant CS vector. Its presence makes the vacuum optically active that has been recently estimated from astrophysical data. We examine two possibilities for the CS vector to be time-like or space-like, under the assumption that it originates from v.e.v. of some pseudoscalar matter. It is shown that: a) a time-like CS vector makes the vacuum unstable under pairs creation of tachyonic photon modes with the finite vacuum decay rate, i.e. it is unlikely realized at macroscopic time scales; b) on the contrary, the space-like CS vector does not yield any tachyonic modes and, moreover, if its dynamical counterpart is substantially described by a scale invariant interaction, then the QED radiation effects induce the dynamical breaking of Lorentz symmetry, i.e. the occurrence of space-like CS vector appears to be rather natural.
[ { "created": "Wed, 29 Apr 1998 18:16:20 GMT", "version": "v1" }, { "created": "Fri, 8 May 1998 16:34:26 GMT", "version": "v2" }, { "created": "Wed, 24 Jun 1998 16:10:35 GMT", "version": "v3" } ]
2009-10-31
[ [ "Andrianov", "A. A.", "", "St.Petersburg U. and U. of Barcelona" ], [ "Soldati", "R.", "", "U. of Bologna" ] ]
A tiny Lorentz symmetry breaking can be mediated in Electrodynamics by means of the Chern-Simons (CS) interaction polarized along a constant CS vector. Its presence makes the vacuum optically active that has been recently estimated from astrophysical data. We examine two possibilities for the CS vector to be time-like or space-like, under the assumption that it originates from v.e.v. of some pseudoscalar matter. It is shown that: a) a time-like CS vector makes the vacuum unstable under pairs creation of tachyonic photon modes with the finite vacuum decay rate, i.e. it is unlikely realized at macroscopic time scales; b) on the contrary, the space-like CS vector does not yield any tachyonic modes and, moreover, if its dynamical counterpart is substantially described by a scale invariant interaction, then the QED radiation effects induce the dynamical breaking of Lorentz symmetry, i.e. the occurrence of space-like CS vector appears to be rather natural.
hep-ph/0402099
Yoshiaki Umeda
Kaoru Hagiwara, Shinya Kanemura, Yoshiaki Umeda
One-loop contributions of charginos and neutralinos to W+ W- production in e+ e- collisions
To appear in the Proceedings of SUSY 2003, held at the University of Arizona, Tucson, AZ, 5-10 June 2003
null
null
null
hep-ph
null
We study one-loop effects of charginos and neutralinos on the helicity amplitudes for the process $e^+e^-\to W^+W^-$ in the MSSM. The calculation is tested by using two methods. First, the sum rules among form factors which result from BRS invariance. Second, the decoupling property in the large mass limit is used to test the overall normalization of the amplitudes. The one-loop contribution to the helicity amplitudes is shown as a function of $\mu$ Higgs parameter and $\sqrt{s}$. We also study the effects of the CP-violating phase.
[ { "created": "Tue, 10 Feb 2004 04:27:37 GMT", "version": "v1" } ]
2007-05-23
[ [ "Hagiwara", "Kaoru", "" ], [ "Kanemura", "Shinya", "" ], [ "Umeda", "Yoshiaki", "" ] ]
We study one-loop effects of charginos and neutralinos on the helicity amplitudes for the process $e^+e^-\to W^+W^-$ in the MSSM. The calculation is tested by using two methods. First, the sum rules among form factors which result from BRS invariance. Second, the decoupling property in the large mass limit is used to test the overall normalization of the amplitudes. The one-loop contribution to the helicity amplitudes is shown as a function of $\mu$ Higgs parameter and $\sqrt{s}$. We also study the effects of the CP-violating phase.
hep-ph/0703288
Leonard Gamberg
A. Afanasev, M. Anselmino, H. Avakian, G. Cates, J.-P. Chen, E. Chudakov, E. Cisbani, C. de Jager, L. Gamberg, H. Gao, F. Garibaldi, X. Jiang, K. S. Kumar, Z.-E. Meziani, P. J. Mulders, J.-C. Peng, X. Qian, M. Schlegel, P. Souder, F. Yuan, L. Zhu
Transversity and Transverse Spin in Nucleon Structure through SIDIS at Jefferson Lab
7 Pages, 2 figures. Summary of the working group on Transversity and Transverse Spin Physics, from the workshop, "Inclusive and Semi-Inclusive Spin Physics with High Luminosity and LargeAcceptance at 11 GeV", Thomas Jefferson National Accelerator Facility (JLAB), December 13-14, 2006, Jefferson Lab, Newport News, VA USA. Serves as input for the Nuclear Physics Long Range Plan on QCD and Hadron Physics
null
null
null
hep-ph
null
The JLab 12 GeV upgrade with a proposed solenoid detector and the CLAS12 detector can provide the granularity and three-dimensional kinematic coverage in longitudinal and transverse momentum, $0.1\le x \le 0.5$, $0.3 \le z \le 0.7$ with $P_T \le 1.5 {\rm GeV}$ to precisely measure the leading twist chiral-odd and $T$-odd quark distribution and fragmentation functions in SIDIS. The large $x$ experimental reach of these detectors with a 12 GeV CEBAF at JLab makes it {\em ideal} to obtain precise data on the {\em valence-dominated} transversity distribution function and to access the tensor charge.
[ { "created": "Tue, 27 Mar 2007 19:20:29 GMT", "version": "v1" } ]
2007-05-23
[ [ "Afanasev", "A.", "" ], [ "Anselmino", "M.", "" ], [ "Avakian", "H.", "" ], [ "Cates", "G.", "" ], [ "Chen", "J. -P.", "" ], [ "Chudakov", "E.", "" ], [ "Cisbani", "E.", "" ], [ "de Jager", "C.", "" ], [ "Gamberg", "L.", "" ], [ "Gao", "H.", "" ], [ "Garibaldi", "F.", "" ], [ "Jiang", "X.", "" ], [ "Kumar", "K. S.", "" ], [ "Meziani", "Z. -E.", "" ], [ "Mulders", "P. J.", "" ], [ "Peng", "J. -C.", "" ], [ "Qian", "X.", "" ], [ "Schlegel", "M.", "" ], [ "Souder", "P.", "" ], [ "Yuan", "F.", "" ], [ "Zhu", "L.", "" ] ]
The JLab 12 GeV upgrade with a proposed solenoid detector and the CLAS12 detector can provide the granularity and three-dimensional kinematic coverage in longitudinal and transverse momentum, $0.1\le x \le 0.5$, $0.3 \le z \le 0.7$ with $P_T \le 1.5 {\rm GeV}$ to precisely measure the leading twist chiral-odd and $T$-odd quark distribution and fragmentation functions in SIDIS. The large $x$ experimental reach of these detectors with a 12 GeV CEBAF at JLab makes it {\em ideal} to obtain precise data on the {\em valence-dominated} transversity distribution function and to access the tensor charge.
1704.01549
Juan Barranco
J. Barranco, D. Delepine, M. Napsuciale and A. Yebra
Distinguishing Dirac and Majorana neutrinos with astrophysical fluxes
6 pages, 5 figures. Upgraded results, title changed
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Massive neutrinos can have helicity $s_{\parallel}\neq -1$. Neutrino helicity changes when the neutrino interacts with an external magnetic field and it is possible that the left-handed neutrinos born inside the Sun or a supernova could leave their sources with a different helicity. Since Dirac and Majorana neutrinos have different cross sections in the scattering on electrons for different neutrino helicities, a change in the final neutrino helicity may generate a different number of events and spectra in terrestrial detectors when astrophysical neutrinos have travelled regions with strong magnetic fields. In this work, we show that looking for these effects in solar neutrinos, it could be possible to set bounds in the neutrino properties such as the neutrino magnetic moment. Furthermore, for neutrinos coming from a supernova, we show that even in the case of an extremely small neutrino magnetic moment, $\mu_\nu \sim 10^{-19}\mu_B$, there will be measurable differences in both the number of events and in the spectra of Majorana and Dirac neutrinos.
[ { "created": "Wed, 5 Apr 2017 17:51:42 GMT", "version": "v1" }, { "created": "Mon, 10 Dec 2018 19:39:17 GMT", "version": "v2" } ]
2018-12-12
[ [ "Barranco", "J.", "" ], [ "Delepine", "D.", "" ], [ "Napsuciale", "M.", "" ], [ "Yebra", "A.", "" ] ]
Massive neutrinos can have helicity $s_{\parallel}\neq -1$. Neutrino helicity changes when the neutrino interacts with an external magnetic field and it is possible that the left-handed neutrinos born inside the Sun or a supernova could leave their sources with a different helicity. Since Dirac and Majorana neutrinos have different cross sections in the scattering on electrons for different neutrino helicities, a change in the final neutrino helicity may generate a different number of events and spectra in terrestrial detectors when astrophysical neutrinos have travelled regions with strong magnetic fields. In this work, we show that looking for these effects in solar neutrinos, it could be possible to set bounds in the neutrino properties such as the neutrino magnetic moment. Furthermore, for neutrinos coming from a supernova, we show that even in the case of an extremely small neutrino magnetic moment, $\mu_\nu \sim 10^{-19}\mu_B$, there will be measurable differences in both the number of events and in the spectra of Majorana and Dirac neutrinos.
hep-ph/9806370
Gabor Papp
Romuald A. Janik, Maciej A. Nowak, Gabor Papp and Ismail Zahed
Random Matrices and Chiral Symmetry in QCD
Talk presented by MAN at "Hadrons in Dense Matter",Seoul, 1997. 23 pages with 6 EPS figures included
null
null
null
hep-ph
null
In this talk we review some recent results from random matrix models as applied to some non-perturbative issues in QCD. All of the issues we will discuss touched upon the important phenomenon related to the spontaneous breaking of chiral symmetry. The afore mentioned insights are: 1. Spontaneous breakdown of chiral symmetry and disorder. 2. Universal microscopic properties of the eigenvalues of the Dirac operator in the vacuum. 3. Universal microscopic properties of the eigenvalues of the Dirac operator in matter. 4. Structural changes of the Dirac spectrum - finite temperature. 5. Structural changes of the Dirac spectrum - finite baryonic density - ``phony vacua'' 6. Structural changes of the Dirac spectrum - finite baryonic density - ``true vacua'' . 7. Phase diagram. 8. Critical parameters. 9. Critical exponents. 10. $U(1)_A$ problem. 11. Screening of the pseudoscalar susceptibility. 12. Strong CP violation (finite $\theta$).
[ { "created": "Mon, 15 Jun 1998 15:05:29 GMT", "version": "v1" } ]
2007-05-23
[ [ "Janik", "Romuald A.", "" ], [ "Nowak", "Maciej A.", "" ], [ "Papp", "Gabor", "" ], [ "Zahed", "Ismail", "" ] ]
In this talk we review some recent results from random matrix models as applied to some non-perturbative issues in QCD. All of the issues we will discuss touched upon the important phenomenon related to the spontaneous breaking of chiral symmetry. The afore mentioned insights are: 1. Spontaneous breakdown of chiral symmetry and disorder. 2. Universal microscopic properties of the eigenvalues of the Dirac operator in the vacuum. 3. Universal microscopic properties of the eigenvalues of the Dirac operator in matter. 4. Structural changes of the Dirac spectrum - finite temperature. 5. Structural changes of the Dirac spectrum - finite baryonic density - ``phony vacua'' 6. Structural changes of the Dirac spectrum - finite baryonic density - ``true vacua'' . 7. Phase diagram. 8. Critical parameters. 9. Critical exponents. 10. $U(1)_A$ problem. 11. Screening of the pseudoscalar susceptibility. 12. Strong CP violation (finite $\theta$).
2303.06093
Joao Pulido
Jo\~ao Penedo and Jo\~ao Pulido
Sterile neutrinos along the DUNE decay pipe
Contribution to DISCRETE 2022, 7-11 November 2022, Kongresshaus Baden-Baden, Germany
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We analyse the sensitivity of the Deep Underground Neutrino Experiment (DUNE) to a sterile neutrino, combining information from both the Near Detector (ND) and the Far Detector (FD). DUNE's sterile exclusion reach is affected by taking into account the information on the neutrino production point, in contrast to assuming a point-like neutrino source. Visible differences remain after taking into account energy bin-to-bin uncorrelated systematics.
[ { "created": "Fri, 10 Mar 2023 17:21:36 GMT", "version": "v1" } ]
2023-03-13
[ [ "Penedo", "João", "" ], [ "Pulido", "João", "" ] ]
We analyse the sensitivity of the Deep Underground Neutrino Experiment (DUNE) to a sterile neutrino, combining information from both the Near Detector (ND) and the Far Detector (FD). DUNE's sterile exclusion reach is affected by taking into account the information on the neutrino production point, in contrast to assuming a point-like neutrino source. Visible differences remain after taking into account energy bin-to-bin uncorrelated systematics.
hep-ph/9707230
Kim Maltman
Kim Maltman and Carl E. Wolfe (York University)
Isospin-Breaking Vacuum-to-Pi^0,Eta Pseudoscalar Matrix Elements at Next-to-Leading Order in the Chiral Expansion
9 pages, 1 postscript figure
Mod.Phys.Lett. A13 (1998) 1347-1360
10.1142/S0217732398001418
null
hep-ph nucl-th
null
We employ Chiral Perturbation Theory (ChPT) to evaluate the complete set of pseudoscalar matrix elements, <0|P_f|pi^0,eta>, with P_f any of the flavor-diagonal pseudoscalar currents (f=u,d,s), to order (m_d-m_u), and to next-to-leading order in the chiral expansion. These matrix elements represent the basic input to a QCD sum rule analysis of isospin breaking in the pi NN couplings using the three-point-function method. We discuss also how one could use the results to construct a one parameter family of interpolating fields for the $\pi^0$, all of whose members have zero vacuum-to-$\eta$ matrix element, and explain how this could in principle be used to provide non-trivial tests of the reliability of the assumptions underlying the use of the three-point-function method. It is shown that the isospin-breaking mixing parameters required for this construction receive significant corrections beyond leading order in the chiral expansion.
[ { "created": "Thu, 3 Jul 1997 06:06:44 GMT", "version": "v1" } ]
2009-10-30
[ [ "Maltman", "Kim", "", "York University" ], [ "Wolfe", "Carl E.", "", "York University" ] ]
We employ Chiral Perturbation Theory (ChPT) to evaluate the complete set of pseudoscalar matrix elements, <0|P_f|pi^0,eta>, with P_f any of the flavor-diagonal pseudoscalar currents (f=u,d,s), to order (m_d-m_u), and to next-to-leading order in the chiral expansion. These matrix elements represent the basic input to a QCD sum rule analysis of isospin breaking in the pi NN couplings using the three-point-function method. We discuss also how one could use the results to construct a one parameter family of interpolating fields for the $\pi^0$, all of whose members have zero vacuum-to-$\eta$ matrix element, and explain how this could in principle be used to provide non-trivial tests of the reliability of the assumptions underlying the use of the three-point-function method. It is shown that the isospin-breaking mixing parameters required for this construction receive significant corrections beyond leading order in the chiral expansion.
hep-ph/0008080
K. Zuber
K. Zuber
Effective Majorana neutrino masses
Contributed paper to XIX Int. Conf. on Neutrino Physics and Astrophysics (Neutrino 2000), Sudbury, June 2000. 8 pages, 4 figures
null
null
null
hep-ph
null
A generalisation of the neutrinoless double beta decay process is presented. Neutrinoless double beta decay measures only one out of nine possible effective Majorana neutrino masses in case of three flavours. Limits obtained for all the matrix elements - some of them for the first time - are presented using data from $\mu - e$ conversion, neutrino-nucleon scattering, HERA and rare kaon decays. An outlook towards future possibilities to improve on the bounds is given.
[ { "created": "Wed, 9 Aug 2000 14:52:04 GMT", "version": "v1" } ]
2007-05-23
[ [ "Zuber", "K.", "" ] ]
A generalisation of the neutrinoless double beta decay process is presented. Neutrinoless double beta decay measures only one out of nine possible effective Majorana neutrino masses in case of three flavours. Limits obtained for all the matrix elements - some of them for the first time - are presented using data from $\mu - e$ conversion, neutrino-nucleon scattering, HERA and rare kaon decays. An outlook towards future possibilities to improve on the bounds is given.
1607.08051
S Dev Sharma
S. Dev, Desh Raj, Radha Raman Gautam
Deviations in Tribimaximal Mixing From Sterile Neutrino Sector
13 pages, 5 figures, 2 tables
Nucl.Phys.B 911 (2016) 744-753
10.1016/j.nuclphysb.2016.08.015
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We explore the possibility of generating a non-zero $U_{e3}$ element of the neutrino mixing matrix from tribimaximal neutrino mixing by adding a light sterile neutrino to the active neutrinos. Small active-sterile mixing can provide the necessary deviation from tribimaximal mixing to generate a non-zero $\theta_{13}$ and atmospheric mixing $\theta_{23}$ different from maximal. Assuming no CP-violation, we study the phenomenological impact of sterile neutrinos in the context of current neutrino oscillation data. The tribimaximal pattern is broken in such a manner that the second column of tribimaximal mixing remains intact in the neutrino mixing matrix.
[ { "created": "Wed, 27 Jul 2016 11:48:51 GMT", "version": "v1" }, { "created": "Thu, 6 Oct 2016 08:13:54 GMT", "version": "v2" } ]
2016-10-11
[ [ "Dev", "S.", "" ], [ "Raj", "Desh", "" ], [ "Gautam", "Radha Raman", "" ] ]
We explore the possibility of generating a non-zero $U_{e3}$ element of the neutrino mixing matrix from tribimaximal neutrino mixing by adding a light sterile neutrino to the active neutrinos. Small active-sterile mixing can provide the necessary deviation from tribimaximal mixing to generate a non-zero $\theta_{13}$ and atmospheric mixing $\theta_{23}$ different from maximal. Assuming no CP-violation, we study the phenomenological impact of sterile neutrinos in the context of current neutrino oscillation data. The tribimaximal pattern is broken in such a manner that the second column of tribimaximal mixing remains intact in the neutrino mixing matrix.
hep-ph/0609171
Giuseppe Bozzi
Giuseppe Bozzi
QCD corrections to Higgs physics at the LHC
4 pages, talk given at IFAE 2006, Pavia, Italy, April 19-21 2006; references added in version 2
null
null
null
hep-ph
null
We summarize the status of QCD corrections for SM Higgs boson production at hadron colliders and briefly sketch the main search strategies at the LHC.
[ { "created": "Mon, 18 Sep 2006 15:33:31 GMT", "version": "v1" }, { "created": "Thu, 21 Sep 2006 12:26:59 GMT", "version": "v2" } ]
2007-05-23
[ [ "Bozzi", "Giuseppe", "" ] ]
We summarize the status of QCD corrections for SM Higgs boson production at hadron colliders and briefly sketch the main search strategies at the LHC.
1108.5740
Chang Sub Shin
Chang Sub Shin
Anomalous U(1) Mediation in Large Volume Compactification
28pages, no fig
JHEP 01 (2012) 084
10.1007/JHEP01(2012)084
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the general effects of anomalous U(1)_A gauge symmetry on soft supersymmetry (SUSY) breaking terms in large volume scenario, where the MSSM sector is localized on a small cycle whose volume is stabilized by the D-term potential of the U(1)_A. Since it obtains SUSY breaking mass regardless of the detailed form of K\"ahler potential, the U(1)_A vector superfield acts as a messenger mediating the SUSY breaking in the moduli sector to the MSSM sector. Then, through the loops of U(1)_A vector superfield, there arise soft masses of the order of m_{3/2}^2/8\pi^2 for scalar mass squares, m_{3/2}/(8\pi^2)^2 for gaugino masses, and m_{3/2}/8\pi^2 for A-paramteres. In addition, the massive U(1)_A vector superfield can have non-zero F and D-components through the moduli mixing in the K\"ahler potential, and this can result in larger soft masses depending upon the details of the moduli mixing. For instance, in the presence of one-loop induced moduli mixing between the visible sector modulus and the large volume modulus, the U(1)_A D-term provides soft scalar mass squares of the order of m_{3/2}^2. However, if the visible sector modulus is mixed only with small cycle moduli, its effect on soft terms depends on how to stabilize the small cycle moduli.
[ { "created": "Mon, 29 Aug 2011 20:11:08 GMT", "version": "v1" }, { "created": "Thu, 12 Jan 2012 05:42:45 GMT", "version": "v2" } ]
2012-02-02
[ [ "Shin", "Chang Sub", "" ] ]
We study the general effects of anomalous U(1)_A gauge symmetry on soft supersymmetry (SUSY) breaking terms in large volume scenario, where the MSSM sector is localized on a small cycle whose volume is stabilized by the D-term potential of the U(1)_A. Since it obtains SUSY breaking mass regardless of the detailed form of K\"ahler potential, the U(1)_A vector superfield acts as a messenger mediating the SUSY breaking in the moduli sector to the MSSM sector. Then, through the loops of U(1)_A vector superfield, there arise soft masses of the order of m_{3/2}^2/8\pi^2 for scalar mass squares, m_{3/2}/(8\pi^2)^2 for gaugino masses, and m_{3/2}/8\pi^2 for A-paramteres. In addition, the massive U(1)_A vector superfield can have non-zero F and D-components through the moduli mixing in the K\"ahler potential, and this can result in larger soft masses depending upon the details of the moduli mixing. For instance, in the presence of one-loop induced moduli mixing between the visible sector modulus and the large volume modulus, the U(1)_A D-term provides soft scalar mass squares of the order of m_{3/2}^2. However, if the visible sector modulus is mixed only with small cycle moduli, its effect on soft terms depends on how to stabilize the small cycle moduli.
hep-ph/9601390
Apostolos Pilaftsis
Bernd A. Kniehl (Max-Planck-Institute) and Apostolos Pilaftsis (Rutherford Lab)
Mixing Renormalization in Majorana Neutrino Theories
24 pages (3 figures included), LaTeX
Nucl.Phys. B474 (1996) 286-308
10.1016/0550-3213(96)00280-5
RAL-TR/96-002 and MPI/PhT/96-005
hep-ph
null
The renormalization of general theories with inter-family mixing of Dirac and/or Majorana fermions is studied at the one-loop electroweak order. The phenomenological significance of the mixing-matrix renormalization is discussed, within the context of models based on the SU(2)_L x U(1)_Y gauge group. The effect of radiative neutrino masses present in these models is naturally taken into account in this formulation. As an example, charged-lepton universality in pion decays is investigated in the heavy- neutrino limit. Non-decoupling heavy-neutrino effects induced by mixing renormalization are found to considerably affect the predictions in these new-physics scenarios.
[ { "created": "Wed, 31 Jan 1996 20:53:50 GMT", "version": "v1" } ]
2009-10-28
[ [ "Kniehl", "Bernd A.", "", "Max-Planck-Institute" ], [ "Pilaftsis", "Apostolos", "", "Rutherford Lab" ] ]
The renormalization of general theories with inter-family mixing of Dirac and/or Majorana fermions is studied at the one-loop electroweak order. The phenomenological significance of the mixing-matrix renormalization is discussed, within the context of models based on the SU(2)_L x U(1)_Y gauge group. The effect of radiative neutrino masses present in these models is naturally taken into account in this formulation. As an example, charged-lepton universality in pion decays is investigated in the heavy- neutrino limit. Non-decoupling heavy-neutrino effects induced by mixing renormalization are found to considerably affect the predictions in these new-physics scenarios.
1109.6232
Miguel Arana-Catania
M. Arana-Catania, S. Heinemeyer, M.J. Herrero and S. Penaranda
Higgs Boson masses and B-Physics Constraints in Non-Minimal Flavor Violating SUSY scenarios
58 pages, 15 figures, Minor modifications, version to appear in JHEP
null
10.1007/JHEP05(2012)015
IFT-UAM/CSIC-11-57
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present one-loop corrections to the Higgs boson masses in the MSSM with Non-Minimal Flavor Violation. The flavor violation is generated from the hypothesis of general flavor mixing in the squark mass matrices, and these are parameterized by a complete set of delta^XY_ij (X, Y = L,R; i; j = t, c, u or b, s, d). We calculate the corrections to the Higgs masses in terms of these delta^XY_ij taking into account all relevant restrictions from B-physics data. This includes constraints from BR(B -> Xs gamma), BR(Bs -> mu+ mu-) and delta M_B_s . After taking into account these constraints we find sizable corrections to the Higgs boson masses, in the case of the lightest MSSM Higgs boson mass exceeding tens of GeV. These corrections are found mainly for the low tan beta case. In the case of a Higgs boson mass measurement these corrections might be used to set further constraints on delta^XY_ij.
[ { "created": "Mon, 26 Sep 2011 15:17:46 GMT", "version": "v1" }, { "created": "Wed, 14 Dec 2011 16:38:30 GMT", "version": "v2" }, { "created": "Mon, 9 Apr 2012 18:21:25 GMT", "version": "v3" } ]
2015-05-30
[ [ "Arana-Catania", "M.", "" ], [ "Heinemeyer", "S.", "" ], [ "Herrero", "M. J.", "" ], [ "Penaranda", "S.", "" ] ]
We present one-loop corrections to the Higgs boson masses in the MSSM with Non-Minimal Flavor Violation. The flavor violation is generated from the hypothesis of general flavor mixing in the squark mass matrices, and these are parameterized by a complete set of delta^XY_ij (X, Y = L,R; i; j = t, c, u or b, s, d). We calculate the corrections to the Higgs masses in terms of these delta^XY_ij taking into account all relevant restrictions from B-physics data. This includes constraints from BR(B -> Xs gamma), BR(Bs -> mu+ mu-) and delta M_B_s . After taking into account these constraints we find sizable corrections to the Higgs boson masses, in the case of the lightest MSSM Higgs boson mass exceeding tens of GeV. These corrections are found mainly for the low tan beta case. In the case of a Higgs boson mass measurement these corrections might be used to set further constraints on delta^XY_ij.
2406.19455
Marvin Schnubel
Hooman Davoudiasl and Marvin Schnubel
Bringing Peccei-Quinn Mechanism Down to Earth
7 pages, 2 figures
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It is conventionally assumed that the physics underlying the Peccei-Quinn (PQ) mechanism for addressing the strong CP problem is at very high energies, orders of magnitude above the weak scale. However, this may not be the case in general and the associated PQ boson $\phi$, besides the signature state, {\it i.e.} the ultralight axion $a$, may emerge well below the weak scale. We consider this possibility and examine some of the conditions for its viability. The example model proposed here may also provide the requisite Standard Model Higgs mass parameter, without invoking new scalars above the GeV scale. The corresponding parameter space can maintain {\it finite naturalness} against quantum corrections. This scenario, depending on choice of parameters, can potentially be constrained by flavor data. We point out that the current mild excess in $B^+\to K^+ \nu \bar \nu$, reported by the Belle II experiment, could be explained in this setup as $B^+\to K^+ \phi$ and $B^+\to K^+ a$, with both $\phi$ and $a$ escaping the detector as missing energy. For a sufficiently heavy PQ boson, in the GeV regime, one can separate these two contributions, due to the difference in $K^+$ momenta. In this case, the axion may also affect lighter meson, {\it e.g.} kaon, decays while $\phi$ would not be a kinematically allowed final state.
[ { "created": "Thu, 27 Jun 2024 18:00:06 GMT", "version": "v1" } ]
2024-07-01
[ [ "Davoudiasl", "Hooman", "" ], [ "Schnubel", "Marvin", "" ] ]
It is conventionally assumed that the physics underlying the Peccei-Quinn (PQ) mechanism for addressing the strong CP problem is at very high energies, orders of magnitude above the weak scale. However, this may not be the case in general and the associated PQ boson $\phi$, besides the signature state, {\it i.e.} the ultralight axion $a$, may emerge well below the weak scale. We consider this possibility and examine some of the conditions for its viability. The example model proposed here may also provide the requisite Standard Model Higgs mass parameter, without invoking new scalars above the GeV scale. The corresponding parameter space can maintain {\it finite naturalness} against quantum corrections. This scenario, depending on choice of parameters, can potentially be constrained by flavor data. We point out that the current mild excess in $B^+\to K^+ \nu \bar \nu$, reported by the Belle II experiment, could be explained in this setup as $B^+\to K^+ \phi$ and $B^+\to K^+ a$, with both $\phi$ and $a$ escaping the detector as missing energy. For a sufficiently heavy PQ boson, in the GeV regime, one can separate these two contributions, due to the difference in $K^+$ momenta. In this case, the axion may also affect lighter meson, {\it e.g.} kaon, decays while $\phi$ would not be a kinematically allowed final state.
2207.10088
Juan Carlos Criado
Juan Carlos Criado, Roman Kogler, Michael Spannowsky
QFitter -- A Quantum Fitting Framework Applied to Effective Field Theories
10 pages, 4 figures
null
10.1103/PhysRevD.107.015023
DESY-22-126, IPPP/22/51
hep-ph hep-th quant-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The use of experimental data to constrain the values of the Wilson coefficients of an Effective Field Theory (EFT) involves minimising a $\chi^2$ function that may contain local minima. Classical optimisation algorithms can become trapped in these minima, preventing the determination of the global minimum. The quantum annealing framework has the potential to overcome this limitation and reliably find the global minimum of non-convex functions. We present QFitter, a quantum annealing method to perform EFT fits. Using a state-of-the-art quantum annealer, we show with concrete examples that QFitter can be used to fit sets of at least eight coefficients, including their quadratic contributions. An arbitrary number of observables can be included without changing the required number of qubits. We provide an example in which $\chi^2$ is non-convex and show that QFitter can find the global minimum more accurately than its classical alternatives.
[ { "created": "Wed, 20 Jul 2022 18:00:00 GMT", "version": "v1" } ]
2023-02-08
[ [ "Criado", "Juan Carlos", "" ], [ "Kogler", "Roman", "" ], [ "Spannowsky", "Michael", "" ] ]
The use of experimental data to constrain the values of the Wilson coefficients of an Effective Field Theory (EFT) involves minimising a $\chi^2$ function that may contain local minima. Classical optimisation algorithms can become trapped in these minima, preventing the determination of the global minimum. The quantum annealing framework has the potential to overcome this limitation and reliably find the global minimum of non-convex functions. We present QFitter, a quantum annealing method to perform EFT fits. Using a state-of-the-art quantum annealer, we show with concrete examples that QFitter can be used to fit sets of at least eight coefficients, including their quadratic contributions. An arbitrary number of observables can be included without changing the required number of qubits. We provide an example in which $\chi^2$ is non-convex and show that QFitter can find the global minimum more accurately than its classical alternatives.
1105.2848
Sean Tulin
Sean Tulin and Peter Winslow
Anomalous B meson mixing and baryogenesis in a two Higgs doublet model with top-charm flavor violation
8 pages, 5 figures
Phys.Rev.D84:034013,2011
10.1103/PhysRevD.84.034013
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
There exist experimental hints from the B sector for CP violation beyond the Standard Model (SM) CKM paradigm. An anomalous dimuon asymmetry was reported by the D0 collaboration, while tension exists between $B \to \tau \nu$ and $S_{\psi K}$. These measurements, disfavoring the SM at the ~3$\sigma$ level, can be explained by new physics in both $B_d$-$\bar{B}_d$ and $B_s$- $\bar{B}_s$ mixing, arising from (1) new bosonic degrees of freedom at or near the electroweak scale, and (2) new, large CP-violating phases. These two new physics ingredients are precisely what is required for electroweak baryogenesis to work in an extension of the SM. We show that a simple two Higgs doublet model with top-charm flavor violation can explain the B anomalies and the baryon asymmetry of the Universe. Moreover, the presence of a large relative phase in the top-charm Yukawa coupling, favored by $B_{d,s}$-$\bar{B}_{d,s}$ mixing, weakens constraints from $\epsilon_K$ and $b \to s \gamma$, allowing for a light charged Higgs mass of O(100 GeV).
[ { "created": "Fri, 13 May 2011 22:25:56 GMT", "version": "v1" } ]
2011-09-08
[ [ "Tulin", "Sean", "" ], [ "Winslow", "Peter", "" ] ]
There exist experimental hints from the B sector for CP violation beyond the Standard Model (SM) CKM paradigm. An anomalous dimuon asymmetry was reported by the D0 collaboration, while tension exists between $B \to \tau \nu$ and $S_{\psi K}$. These measurements, disfavoring the SM at the ~3$\sigma$ level, can be explained by new physics in both $B_d$-$\bar{B}_d$ and $B_s$- $\bar{B}_s$ mixing, arising from (1) new bosonic degrees of freedom at or near the electroweak scale, and (2) new, large CP-violating phases. These two new physics ingredients are precisely what is required for electroweak baryogenesis to work in an extension of the SM. We show that a simple two Higgs doublet model with top-charm flavor violation can explain the B anomalies and the baryon asymmetry of the Universe. Moreover, the presence of a large relative phase in the top-charm Yukawa coupling, favored by $B_{d,s}$-$\bar{B}_{d,s}$ mixing, weakens constraints from $\epsilon_K$ and $b \to s \gamma$, allowing for a light charged Higgs mass of O(100 GeV).
1106.2230
I.V. Danilkin
I.V. Danilkin, L.I.R. Gil, M.F.M. Lutz
Dynamical light vector mesons in low-energy scattering of Goldstone bosons
15 pages, 8 figures, typos corrected, accepted for publication in Physics Letters B
Phys.Lett.B703:504-509,2011
10.1016/j.physletb.2011.08.001
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a study of Goldstone boson scattering based on the flavor SU(3) chiral Lagrangian formulated with vector mesons in the tensor field representation. A coupled-channel channel computation is confronted with the empirical s- and p-wave phase shifts, where good agreement with the data set is obtained up to about 1.2 GeV. There are two relevant free parameters only, the chiral limit value of the pion decay constant and the coupling constant characterizing the decay of the rho meson into a pair of pions. We apply a recently suggested approach that implements constraints from micro- causality and coupled-channel unitarity. Generalized potentials are obtained from the chiral Lagrangian and are expanded in terms of suitably constructed conformal variables. The partial-wave scattering amplitudes are defined as solutions of non-linear integral equations that are solved by means of an N/D ansatz.
[ { "created": "Sat, 11 Jun 2011 12:09:15 GMT", "version": "v1" }, { "created": "Fri, 9 Sep 2011 12:22:18 GMT", "version": "v2" } ]
2011-09-13
[ [ "Danilkin", "I. V.", "" ], [ "Gil", "L. I. R.", "" ], [ "Lutz", "M. F. M.", "" ] ]
We present a study of Goldstone boson scattering based on the flavor SU(3) chiral Lagrangian formulated with vector mesons in the tensor field representation. A coupled-channel channel computation is confronted with the empirical s- and p-wave phase shifts, where good agreement with the data set is obtained up to about 1.2 GeV. There are two relevant free parameters only, the chiral limit value of the pion decay constant and the coupling constant characterizing the decay of the rho meson into a pair of pions. We apply a recently suggested approach that implements constraints from micro- causality and coupled-channel unitarity. Generalized potentials are obtained from the chiral Lagrangian and are expanded in terms of suitably constructed conformal variables. The partial-wave scattering amplitudes are defined as solutions of non-linear integral equations that are solved by means of an N/D ansatz.
hep-ph/9706340
Ryoji Enomoto
Ryoji Enomoto and Masaharu Tanabashi
CP Violation via $\rho \omega$ Interference
7 pages, latex(sprocl.sty included), 2 figures. Talk presented at "Int. Conf. on B-physics and CP violation" Hawaii 97
null
10.1142/9789814503952_0049
KEK preprint-97-67
hep-ph hep-ex
null
We consider $B^{\pm,0} \to \rho^0(\omega)h^{\pm,0}$, where $\rho^0(\omega)$ decays to $\pi^+\pi^-$ and $h$ is any hadronic final state, such as $\pi$ or $K$. We find a large direct CP asymmetry in B-meson decays via $\rho \omega$ interference. A possible method to determine weak phases, such as $\phi_{2,3}$, is discussed. The experimental feasibility is also shown.
[ { "created": "Thu, 12 Jun 1997 08:47:25 GMT", "version": "v1" }, { "created": "Fri, 13 Jun 1997 06:37:34 GMT", "version": "v2" } ]
2016-11-03
[ [ "Enomoto", "Ryoji", "" ], [ "Tanabashi", "Masaharu", "" ] ]
We consider $B^{\pm,0} \to \rho^0(\omega)h^{\pm,0}$, where $\rho^0(\omega)$ decays to $\pi^+\pi^-$ and $h$ is any hadronic final state, such as $\pi$ or $K$. We find a large direct CP asymmetry in B-meson decays via $\rho \omega$ interference. A possible method to determine weak phases, such as $\phi_{2,3}$, is discussed. The experimental feasibility is also shown.
hep-ph/0102311
Boris Arbuzov
B.A. Arbuzov
Higgs' mass around 115 GeV would testify for composite Higgs
16 pages, latex, 6 figures, 1 table
null
null
null
hep-ph
null
Theory with $SU(2)\times U(1)$ gauge invariant electroweak Lagrangian describing standard interaction of massless quark doublet without elementary scalar Higgs sector is considered. We show in the main order of $1/N_c$ expansion, that there exists a solution, which breaks initial symmetry and is accompanied by an appearance of zero mass composite scalar doublet. The electroweak loop corrections shift its mass to a tachyon value and thus the scalar serves as a substitute for usual elementary Higgs. The $t$-quark mass also arise. The problem of adjusting its observable mass leads to prediction of triple gauge constant $\lambda_V \simeq -0.034$ without contradiction with experimental data. The mass of the surviving composite Higgs scalar is predicted to be $M_H = 117 \pm 7 GeV$, that agrees with recent indications of $M_H \simeq 115 GeV$. The resulting theory contains realistic $W, Z, t$ masses, composite massive Higgs and massless other particles. Parameters used are cut-off $\Lambda \simeq 3500 GeV$, weak gauge constant $g$ and mixing angle $\theta_W$.
[ { "created": "Mon, 26 Feb 2001 10:29:23 GMT", "version": "v1" } ]
2007-05-23
[ [ "Arbuzov", "B. A.", "" ] ]
Theory with $SU(2)\times U(1)$ gauge invariant electroweak Lagrangian describing standard interaction of massless quark doublet without elementary scalar Higgs sector is considered. We show in the main order of $1/N_c$ expansion, that there exists a solution, which breaks initial symmetry and is accompanied by an appearance of zero mass composite scalar doublet. The electroweak loop corrections shift its mass to a tachyon value and thus the scalar serves as a substitute for usual elementary Higgs. The $t$-quark mass also arise. The problem of adjusting its observable mass leads to prediction of triple gauge constant $\lambda_V \simeq -0.034$ without contradiction with experimental data. The mass of the surviving composite Higgs scalar is predicted to be $M_H = 117 \pm 7 GeV$, that agrees with recent indications of $M_H \simeq 115 GeV$. The resulting theory contains realistic $W, Z, t$ masses, composite massive Higgs and massless other particles. Parameters used are cut-off $\Lambda \simeq 3500 GeV$, weak gauge constant $g$ and mixing angle $\theta_W$.
hep-ph/0501230
Selma Uhlig
Andrzej J. Buras, Anton Poschenrieder, Selma Uhlig
Non-Decoupling Effects of the Heavy T in the B^0_{d,s}-\bar B^0_{d,s} Mixing and Rare K and B Decays
13 pages, 6 figures
null
null
null
hep-ph
null
We point out that in the case of a heavy top quark T, present in the Littlest Higgs model (LH), and the t-T mixing parameter x_L > 0.90 the contribution to B^0_{d,s}-\bar B^0_{d,s} mixing from box diagrams with two T exchanges cannot be neglected. Although formally O(v^4/f^4) with v = 246 GeV and f > 1 TeV, this contribution increases linearly with x_T = m_T^2/M^2_W and with x_T = O(f^2/v^2) constitutes effectively an O(v^2/f^2) correction. For x_L ~ 1, this contribution turns out to be more important than the genuine O(v^2/f^2) corrections. In particular it is larger than the recently calculated O(v^2/f^2) contribution of box diagrams with a single T exchange that increases only logarithmically with x_T. For x_L = 0.95 and f/v = 5,10,15, the short distance function S governing the B^0_{d,s}-\bar B^0_{d,s} mixing mass differences \Delta M_{d,s} receives 56%, 15% and 7% enhancements relative to its Standard Model (SM) value, implying a suppression of the CKM element V_td and an enhancement of \Delta M_s. The short distance functions X and Y, relevant for rare K and B decays, increase only logarithmically with x_T. With the suppressed V_td, K->\pi\nu\bar\nu and B_d->\mu^+\mu^- decays are only insignificantly modified with respect to the SM, while the branching ratio Br(B_s->\mu^+\mu^-) receives 66%, 19% and 9% enhancements for x_L = 0.95 and f/v = 5,10,15, respectively. Similar enhancement is found for Br(B_s->\mu\bar\mu)/Br(B_d->\mu\bar\mu).
[ { "created": "Tue, 25 Jan 2005 15:21:13 GMT", "version": "v1" } ]
2007-05-23
[ [ "Buras", "Andrzej J.", "" ], [ "Poschenrieder", "Anton", "" ], [ "Uhlig", "Selma", "" ] ]
We point out that in the case of a heavy top quark T, present in the Littlest Higgs model (LH), and the t-T mixing parameter x_L > 0.90 the contribution to B^0_{d,s}-\bar B^0_{d,s} mixing from box diagrams with two T exchanges cannot be neglected. Although formally O(v^4/f^4) with v = 246 GeV and f > 1 TeV, this contribution increases linearly with x_T = m_T^2/M^2_W and with x_T = O(f^2/v^2) constitutes effectively an O(v^2/f^2) correction. For x_L ~ 1, this contribution turns out to be more important than the genuine O(v^2/f^2) corrections. In particular it is larger than the recently calculated O(v^2/f^2) contribution of box diagrams with a single T exchange that increases only logarithmically with x_T. For x_L = 0.95 and f/v = 5,10,15, the short distance function S governing the B^0_{d,s}-\bar B^0_{d,s} mixing mass differences \Delta M_{d,s} receives 56%, 15% and 7% enhancements relative to its Standard Model (SM) value, implying a suppression of the CKM element V_td and an enhancement of \Delta M_s. The short distance functions X and Y, relevant for rare K and B decays, increase only logarithmically with x_T. With the suppressed V_td, K->\pi\nu\bar\nu and B_d->\mu^+\mu^- decays are only insignificantly modified with respect to the SM, while the branching ratio Br(B_s->\mu^+\mu^-) receives 66%, 19% and 9% enhancements for x_L = 0.95 and f/v = 5,10,15, respectively. Similar enhancement is found for Br(B_s->\mu\bar\mu)/Br(B_d->\mu\bar\mu).
1805.10482
Barbara Pasquini
B. Pasquini (Pavia U. & INFN, Pavia) and M. Vanderhaeghen (Mainz U., Inst. Kernphysik & U. Mainz, PRISMA)
Dispersion Theory in Electromagnetic Interactions
preprint version of a review to appear in Ann. Rev. Nucl. Part. Sci. 68 (2018)
null
10.1146/annurev-nucl-101917-020843
null
hep-ph hep-ex nucl-ex nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We review various applications of dispersion relations (DRs) to the electromagnetic structure of hadrons. We discuss the way DRs allow one to extract information on hadron structure constants by connecting information from complementary scattering processes. We consider the real and virtual Compton scattering processes off the proton, and summarize recent advances in the DR analysis of experimental data to extract the proton polarizabilities, in comparison with alternative studies based on chiral effective field theories. We discuss a multipole analysis of real Compton scattering data, along with a DR fit of the energy-dependent dynamical polarizabilities. Furthermore, we review new sum rules for the double-virtual Compton scattering process off the proton, which allow for model independent relations between polarizabilities in real and virtual Compton scattering, and moments of nucleon structure functions. The information on the double-virtual Compton scattering is used to predict and constrain the polarizability corrections to muonic hydrogen spectroscopy.
[ { "created": "Sat, 26 May 2018 13:17:50 GMT", "version": "v1" } ]
2018-07-04
[ [ "Pasquini", "B.", "", "Pavia U. & INFN, Pavia" ], [ "Vanderhaeghen", "M.", "", "Mainz U.,\n Inst. Kernphysik & U. Mainz, PRISMA" ] ]
We review various applications of dispersion relations (DRs) to the electromagnetic structure of hadrons. We discuss the way DRs allow one to extract information on hadron structure constants by connecting information from complementary scattering processes. We consider the real and virtual Compton scattering processes off the proton, and summarize recent advances in the DR analysis of experimental data to extract the proton polarizabilities, in comparison with alternative studies based on chiral effective field theories. We discuss a multipole analysis of real Compton scattering data, along with a DR fit of the energy-dependent dynamical polarizabilities. Furthermore, we review new sum rules for the double-virtual Compton scattering process off the proton, which allow for model independent relations between polarizabilities in real and virtual Compton scattering, and moments of nucleon structure functions. The information on the double-virtual Compton scattering is used to predict and constrain the polarizability corrections to muonic hydrogen spectroscopy.
1308.0422
Giampiero Passarino
Giampiero Passarino
Higgs Boson Production and Decay: Dalitz Sector
14 pages, 7 figures
null
10.1016/j.physletb.2013.10.052
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The processes involving a Higgs boson, a photon(gluon) and a fermion pair pose severe challenges to the experimental analysis. They represent rare decays and production mechanisms of the Higgs boson at LHC. However, they are not Yukawa suppressed at next-to-leading order opening a window for the correct definition of pseudo-observables, e.g. a definition of the Higgs decay width into Z + photon with universal inherent meaning, that are currently used in extracting information for the couplings of the newly discovered resonance at LHC. The impact of genuinely electroweak NLO corrections is discussed, as well as the comparison of the full-fledged cross-sections to their zero-width approximation.
[ { "created": "Fri, 2 Aug 2013 07:25:47 GMT", "version": "v1" } ]
2015-06-16
[ [ "Passarino", "Giampiero", "" ] ]
The processes involving a Higgs boson, a photon(gluon) and a fermion pair pose severe challenges to the experimental analysis. They represent rare decays and production mechanisms of the Higgs boson at LHC. However, they are not Yukawa suppressed at next-to-leading order opening a window for the correct definition of pseudo-observables, e.g. a definition of the Higgs decay width into Z + photon with universal inherent meaning, that are currently used in extracting information for the couplings of the newly discovered resonance at LHC. The impact of genuinely electroweak NLO corrections is discussed, as well as the comparison of the full-fledged cross-sections to their zero-width approximation.