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hep-ph/0411210
David Greynat
David Greynat (CPT)
On the rare $K \to \pi \bar l l$ decays
Talk given at the $11^{th}$ High-Energy Physics International Conference on Quantum Chromodynamics, 5-10 July (2004), Montpellier (France)
null
null
null
hep-ph
null
In this talk, we present our recent work on the $K\ra\pi \bar{l} l$ decays in a combined framework of chiral perturbation theory and Large--$N_c$ QCD under the dominance of a minimal narrow resonance structure. The proposed description reproduces very well the experimental Br$(K^+\ra\pi^+ e^+ e^-)$ and Br$(K_S\ra\pi^0 e^+ e^-)$. Predictions for the $K\ra\pi \mu^{+}\mu^{-}$ modes are also obtained and we can conclude to the constructive type for the interference between the {\it direct} and {\it indirect} CP--violation amplitudes in $K_L\ra\pi^0 e^+ e^-$.
[ { "created": "Tue, 16 Nov 2004 15:21:52 GMT", "version": "v1" } ]
2007-05-23
[ [ "Greynat", "David", "", "CPT" ] ]
In this talk, we present our recent work on the $K\ra\pi \bar{l} l$ decays in a combined framework of chiral perturbation theory and Large--$N_c$ QCD under the dominance of a minimal narrow resonance structure. The proposed description reproduces very well the experimental Br$(K^+\ra\pi^+ e^+ e^-)$ and Br$(K_S\ra\pi^0 e^+ e^-)$. Predictions for the $K\ra\pi \mu^{+}\mu^{-}$ modes are also obtained and we can conclude to the constructive type for the interference between the {\it direct} and {\it indirect} CP--violation amplitudes in $K_L\ra\pi^0 e^+ e^-$.
0710.2118
Mu-Chun Chen
Mu-Chun Chen, K.T. Mahanthappa
Tri-bimaximal Neutrino Mixing and CKM Matrix in a SU(5)x(d)T Model
Submitted for the SUSY07 proceedings, 4 pages, LaTeX
Karlsruhe 2007, SUSY 2007, 792-795
10.1088/1742-6596/136/4/042021
COLO-HEP-531, UCI-TR-2007-44
hep-ph
null
In this talk, we present a model based on SU(5)x(d)T which successfully gives rise to near tri-bimaximal leptonic mixing as well as realistic CKM matrix elements for the quarks. The Georgi-Jarlskog relations for three generations are also obtained. Due to the (d)T transformation property of the matter fields, the b-quark mass can be generated only when the (d)T symmetry is broken, giving a dynamical origin for the hierarchy between m_b and m_t. There are only nine operators allowed in the Yukawa sector up to at least mass dimension seven due to an additional Z12 x Z12' symmetry, which also forbids, up to some high orders, operators that lead to proton decay. The resulting model has a total of nine parameters in the charged fermion and neutrino sectors, and hence is very predictive. In addition to the prediction for theta13 ~ theta_c/3sqrt{2}, the model gives rise to a sum rule, tan^2(theta_{solar}) ~ tan^2(theta_{solar,TBM}) - 1/2*theta_c*cos(beta), which is a consequence of the Georgi-Jarlskog relations in the quark sector. This deviation could account for the difference between the experimental best fit value for the solar mixing angle and the value predicted by the tri-bimaximal mixing matrix.
[ { "created": "Thu, 11 Oct 2007 01:42:09 GMT", "version": "v1" } ]
2009-11-13
[ [ "Chen", "Mu-Chun", "" ], [ "Mahanthappa", "K. T.", "" ] ]
In this talk, we present a model based on SU(5)x(d)T which successfully gives rise to near tri-bimaximal leptonic mixing as well as realistic CKM matrix elements for the quarks. The Georgi-Jarlskog relations for three generations are also obtained. Due to the (d)T transformation property of the matter fields, the b-quark mass can be generated only when the (d)T symmetry is broken, giving a dynamical origin for the hierarchy between m_b and m_t. There are only nine operators allowed in the Yukawa sector up to at least mass dimension seven due to an additional Z12 x Z12' symmetry, which also forbids, up to some high orders, operators that lead to proton decay. The resulting model has a total of nine parameters in the charged fermion and neutrino sectors, and hence is very predictive. In addition to the prediction for theta13 ~ theta_c/3sqrt{2}, the model gives rise to a sum rule, tan^2(theta_{solar}) ~ tan^2(theta_{solar,TBM}) - 1/2*theta_c*cos(beta), which is a consequence of the Georgi-Jarlskog relations in the quark sector. This deviation could account for the difference between the experimental best fit value for the solar mixing angle and the value predicted by the tri-bimaximal mixing matrix.
1810.01884
Sacha Davidson
Sacha Davidson, Yoshitaka Kuno and Masato Yamanaka
Selecting mu -> e Conversion Targets to distinguish Lepton Flavour-Changing Operators
13 pages, 3 figures, section added, version accepted for publication
null
10.1016/j.physletb.2019.01.042
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The experimental sensitivity to $\mu \to e$ conversion on nuclei is set to improve by four orders of magnitude in coming years. However, various operator coefficients add coherently in the amplitude for $\mu \to e$ conversion, weighted by nucleus-dependent functions, and therefore in the event of a detection, identifying the relevant new physics scenarios could be difficult. Using a representation of the nuclear targets as vectors in coefficient space, whose components are the weighting functions, we quantify the expectation that different nuclear targets could give different constraints.We show that all but two combinations of the 10 Spin-Independent (SI) coefficients could be constrained by future measurements, but discriminating among the axial, tensor and pseudoscalar operators that contribute to the Spin-Dependent (SD) process would require dedicated nuclear calculations. We anticipate that $\mu \to e$ conversion could constrain 10 to 14 combinations of coefficients; if $\mu \to e \gamma$ and $\mu \to 3e$ constrain eight more, that leaves 60 to 64 "flat directions" in the basis of QED$\times$QCD-invariant operators which describe $\mu \to e$ flavour change below $m_W$.
[ { "created": "Wed, 3 Oct 2018 18:00:02 GMT", "version": "v1" }, { "created": "Sun, 20 Jan 2019 13:43:08 GMT", "version": "v2" } ]
2019-01-30
[ [ "Davidson", "Sacha", "" ], [ "Kuno", "Yoshitaka", "" ], [ "Yamanaka", "Masato", "" ] ]
The experimental sensitivity to $\mu \to e$ conversion on nuclei is set to improve by four orders of magnitude in coming years. However, various operator coefficients add coherently in the amplitude for $\mu \to e$ conversion, weighted by nucleus-dependent functions, and therefore in the event of a detection, identifying the relevant new physics scenarios could be difficult. Using a representation of the nuclear targets as vectors in coefficient space, whose components are the weighting functions, we quantify the expectation that different nuclear targets could give different constraints.We show that all but two combinations of the 10 Spin-Independent (SI) coefficients could be constrained by future measurements, but discriminating among the axial, tensor and pseudoscalar operators that contribute to the Spin-Dependent (SD) process would require dedicated nuclear calculations. We anticipate that $\mu \to e$ conversion could constrain 10 to 14 combinations of coefficients; if $\mu \to e \gamma$ and $\mu \to 3e$ constrain eight more, that leaves 60 to 64 "flat directions" in the basis of QED$\times$QCD-invariant operators which describe $\mu \to e$ flavour change below $m_W$.
1008.3684
Wei-jie Fu
Wei-jie Fu and Yue-liang Wu
Fluctuations and Correlations of Conserved Charges near the QCD Critical Point
22 pages, 12 figures, version accepted by Phys. Rev. D
Phys.Rev.D82:074013,2010
10.1103/PhysRevD.82.074013
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the fluctuations and correlations of conserved charges, i.e. the baryon number, electric charge and the strangeness at finite temperature and nonzero baryon chemical potential with an effective model. The fluctuations are calculated up to the fourth-order and the correlations to the third-order. We find that the second-order fluctuations and correlations have a peak or valley structure when the chiral phase transition takes place with the increase of the baryon chemical potential; the third-order fluctuations and correlations change their signs during the chiral phase transition and the fourth-order fluctuations have two maximum and one minimum. we also depict contour plots of various fluctuations and correlations of conserved charges in the plane of temperature and baryon chemical potential. We find that higher order fluctuations and correlations of conserved charges are superior to the second-order ones to be used to search for the critical point in heavy ion collision experiments.
[ { "created": "Sun, 22 Aug 2010 08:45:53 GMT", "version": "v1" }, { "created": "Tue, 5 Oct 2010 14:30:05 GMT", "version": "v2" } ]
2010-10-27
[ [ "Fu", "Wei-jie", "" ], [ "Wu", "Yue-liang", "" ] ]
We study the fluctuations and correlations of conserved charges, i.e. the baryon number, electric charge and the strangeness at finite temperature and nonzero baryon chemical potential with an effective model. The fluctuations are calculated up to the fourth-order and the correlations to the third-order. We find that the second-order fluctuations and correlations have a peak or valley structure when the chiral phase transition takes place with the increase of the baryon chemical potential; the third-order fluctuations and correlations change their signs during the chiral phase transition and the fourth-order fluctuations have two maximum and one minimum. we also depict contour plots of various fluctuations and correlations of conserved charges in the plane of temperature and baryon chemical potential. We find that higher order fluctuations and correlations of conserved charges are superior to the second-order ones to be used to search for the critical point in heavy ion collision experiments.
hep-ph/0204343
Peter Arnold
Peter Arnold, Guy D. Moore and Laurence G. Yaffe
Photon and Gluon Emission in Relativistic Plasmas
29 pages, 18 figures. Corrected from version 1: missing factor of 1/k in final results and factor of 2 error on gg <-> g contribution to gluon production. (Also changed definition of N_s by a factor of 2.)
JHEP 0206:030,2002
10.1088/1126-6708/2002/06/030
null
hep-ph nucl-th
null
We recently derived, using diagrammatic methods, the leading-order hard photon emission rate in ultra-relativistic plasmas. This requires a correct treatment of multiple scattering effects which limit the coherence length of emitted radiation (the Landau-Pomeranchuk-Migdal effect). In this paper, we provide a more physical derivation of this result, and extend the treatment to the case of gluon radiation.
[ { "created": "Mon, 29 Apr 2002 19:34:39 GMT", "version": "v1" }, { "created": "Tue, 21 May 2002 20:59:47 GMT", "version": "v2" } ]
2010-02-16
[ [ "Arnold", "Peter", "" ], [ "Moore", "Guy D.", "" ], [ "Yaffe", "Laurence G.", "" ] ]
We recently derived, using diagrammatic methods, the leading-order hard photon emission rate in ultra-relativistic plasmas. This requires a correct treatment of multiple scattering effects which limit the coherence length of emitted radiation (the Landau-Pomeranchuk-Migdal effect). In this paper, we provide a more physical derivation of this result, and extend the treatment to the case of gluon radiation.
1512.08941
Jose Rodriguez-Quintero
C. Mezrag, H. Moutarde, J. Rodr\'iguez-Quintero
Pion's valence-quark GPD and its extension beyond DGLAP region
6 pages, 4 figures, contribution to 21st International conference on Few-Body Problems
null
10.1051/epjconf/201611305008
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We briefly report on a recent computation, with the help of a fruitful algebraic model, sketching the pion valence dressed-quark generalized parton distribution and, very preliminary, discuss on a possible avenue to get reliable results in both Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) and Efremov-Radyushkin-Brodsky-Lepage (ERBL) kinematial regions.
[ { "created": "Wed, 30 Dec 2015 13:34:23 GMT", "version": "v1" } ]
2016-04-20
[ [ "Mezrag", "C.", "" ], [ "Moutarde", "H.", "" ], [ "Rodríguez-Quintero", "J.", "" ] ]
We briefly report on a recent computation, with the help of a fruitful algebraic model, sketching the pion valence dressed-quark generalized parton distribution and, very preliminary, discuss on a possible avenue to get reliable results in both Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) and Efremov-Radyushkin-Brodsky-Lepage (ERBL) kinematial regions.
hep-ph/0108176
Gilad Perez
Oleg Khasanov and Gilad Perez
On Neutrino Masses and a Low Breaking Scale of Left-Right Symmetry
18 pages references added published version
Phys.Rev. D65 (2002) 053007
10.1103/PhysRevD.65.053007
WIS/17/01-AUG-DPP
hep-ph
null
In left-right symmetric models (LRSM) the light neutrino masses arise from two sources: the seesaw mechanism and a VEV of an SU(2)$_L$ triplet. If the left-right symmetry breaking, $v_R$, is low, $v_R\lsim15\TeV$, the contributions to the light neutrino masses from both the seesaw mechanism and the triplet Yukawa couplings are expected to be well above the experimental bounds. We present a minimal LRSM with an additional U(1) symmetry in which the masses induced by the two sources are below the eV scale and the two-fold problem is solved. We further show that, if the U(1) symmetry is also responsible for the lepton flavor structure, the model yields a small mixing angle within the first two lepton generations.
[ { "created": "Wed, 22 Aug 2001 16:21:06 GMT", "version": "v1" }, { "created": "Sun, 3 Feb 2002 11:06:41 GMT", "version": "v2" } ]
2009-11-07
[ [ "Khasanov", "Oleg", "" ], [ "Perez", "Gilad", "" ] ]
In left-right symmetric models (LRSM) the light neutrino masses arise from two sources: the seesaw mechanism and a VEV of an SU(2)$_L$ triplet. If the left-right symmetry breaking, $v_R$, is low, $v_R\lsim15\TeV$, the contributions to the light neutrino masses from both the seesaw mechanism and the triplet Yukawa couplings are expected to be well above the experimental bounds. We present a minimal LRSM with an additional U(1) symmetry in which the masses induced by the two sources are below the eV scale and the two-fold problem is solved. We further show that, if the U(1) symmetry is also responsible for the lepton flavor structure, the model yields a small mixing angle within the first two lepton generations.
1905.13273
Rachik Soualah
Rachik Soualah, Salah Nasri and Safa Naseem
Probing the Majorana Nature in Radiative Neutrino mass models with the same-sign dilepton final states at future colliders
Contribution to the 2019 EW session of the 54th Rencontres de Moriond
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Neutrinos in the Standard Model (SM) are considered to be massless which is in contradiction with the evidence from the neutrino oscillation data. These experiments established that at least two SM neutrinos have non-zero masses and that individual lepton numbers are violated. This is strong evidence of new physics beyond the SM that should be responsible for generating non zero mass for the neutrinos. In this work, we study the collider phenomenology of an extension of the SM where neutrinos are generated radiatively at three-loop. We show that the production of same-sign dilepton at lepton colliders (such as FCC-ee and ILC) can be used to probe the Majorana nature of neutrinos in this class of models.
[ { "created": "Thu, 30 May 2019 19:37:27 GMT", "version": "v1" }, { "created": "Fri, 7 Jun 2019 18:20:36 GMT", "version": "v2" } ]
2019-06-11
[ [ "Soualah", "Rachik", "" ], [ "Nasri", "Salah", "" ], [ "Naseem", "Safa", "" ] ]
Neutrinos in the Standard Model (SM) are considered to be massless which is in contradiction with the evidence from the neutrino oscillation data. These experiments established that at least two SM neutrinos have non-zero masses and that individual lepton numbers are violated. This is strong evidence of new physics beyond the SM that should be responsible for generating non zero mass for the neutrinos. In this work, we study the collider phenomenology of an extension of the SM where neutrinos are generated radiatively at three-loop. We show that the production of same-sign dilepton at lepton colliders (such as FCC-ee and ILC) can be used to probe the Majorana nature of neutrinos in this class of models.
hep-ph/0207161
Anna M. Stasto
A.M. Stasto
Running coupling and BFKL pomeron
5 pages, 2 figures, talk given at 10th International Workshop on Deep Inelastic Scattering (DIS2002), Cracow, Poland, 30 Apr - 4 May 2002
Acta Phys.Polon. B33 (2002) 3039-3044
null
null
hep-ph
null
We show that in the case of the BFKL pomeron with running coupling the diffusion pattern is strongly modified and is characterised by the sudden tunneling transition to the non-perturbative regime. We suggest that by using the b - expansion method one can suppress the non-perturbative Pomeron and isolate purely perturbative part of the gluon Green's function.
[ { "created": "Fri, 12 Jul 2002 16:29:03 GMT", "version": "v1" } ]
2007-05-23
[ [ "Stasto", "A. M.", "" ] ]
We show that in the case of the BFKL pomeron with running coupling the diffusion pattern is strongly modified and is characterised by the sudden tunneling transition to the non-perturbative regime. We suggest that by using the b - expansion method one can suppress the non-perturbative Pomeron and isolate purely perturbative part of the gluon Green's function.
hep-ph/9803221
Hans-Werner Hammer
L.L. Barz (1,2), H. Forkel (3,4), H.-W. Hammer (5,6), F.S. Navarra (1), M. Nielsen (1), and M.J. Ramsey-Musolf (6,7) ((1) Sao Paulo, (2) Joinville, (3) Trento, (4) Heidelberg, (5) TRIUMF, (6) INT, (7) Connecticut)
K^* Mesons and Nucleon Strangeness
21 pages, RevTex, 2 PS figures included with epsf.sty
Nucl.Phys. A640 (1998) 259-280
10.1016/S0375-9474(98)00438-2
DOE/ER/40561-345-INT97-00-184
hep-ph nucl-th
null
We study contributions to the nucleon strange quark vector current form factors from intermediate states containing K^* mesons. We show how these contributions may be comparable in magnitude to those made by K mesons, using methods complementary to those employed in quark model studies. We also analyze the degree of theoretical uncertainty associated with K^* contributions.
[ { "created": "Mon, 2 Mar 1998 20:04:15 GMT", "version": "v1" } ]
2009-10-31
[ [ "Barz", "L. L.", "" ], [ "Forkel", "H.", "" ], [ "Hammer", "H. -W.", "" ], [ "Navarra", "F. S.", "" ], [ "Nielsen", "M.", "" ], [ "Ramsey-Musolf", "M. J.", "" ] ]
We study contributions to the nucleon strange quark vector current form factors from intermediate states containing K^* mesons. We show how these contributions may be comparable in magnitude to those made by K mesons, using methods complementary to those employed in quark model studies. We also analyze the degree of theoretical uncertainty associated with K^* contributions.
1406.5334
George Savvidy K
George Savvidy
Tensor gluons and proton structure
LaTex file, 18 pages, 2 figures, note added. arXiv admin note: text overlap with arXiv:1310.0856
Theor.Math.Phys. 182 (2015) 1, 114-129
10.1007/s11232-015-0250-x
NRCPS-HE-28-2014
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In a recent article we were considering a possibility that inside a proton and, more generally, inside hadrons there could be additional partons - tensor-gluons, which carry a part of the proton momentum. Tensor-gluons have zero electric charge, like gluons, but have a larger spin. Therefore we call them tensor-gluons. The nonzero density of tensor-gluons can be generated by the emission of tensor-gluons by gluons. Tensor-gluons can further split into the pairs of tensor-gluons through a different channels. To describe all these processes one should know the general splitting probabilities for tensor-gluons. These probabilities should fulfill very general symmetry relations, which we were able to resolve by introducing a splitting index. This approach allows to find out the general form of the splitting functions, to derive corresponding DGLAP evolution equations and to calculate the one-loop Callan-Simanzik beta function for tensor-gluons of a given spin. Our results provide a nontrivial consistency check of the theory and of the Callan-Simanzik beta function calculations, because the theory has a unique coupling constant and its high energy behavior should be universal for all particles of the spectrum. We argue that the contribution of all spins into the beta function vanishes leading to a conformal invariant theory at very high energies.
[ { "created": "Fri, 20 Jun 2014 09:45:23 GMT", "version": "v1" }, { "created": "Sun, 14 Dec 2014 17:43:13 GMT", "version": "v2" } ]
2015-02-10
[ [ "Savvidy", "George", "" ] ]
In a recent article we were considering a possibility that inside a proton and, more generally, inside hadrons there could be additional partons - tensor-gluons, which carry a part of the proton momentum. Tensor-gluons have zero electric charge, like gluons, but have a larger spin. Therefore we call them tensor-gluons. The nonzero density of tensor-gluons can be generated by the emission of tensor-gluons by gluons. Tensor-gluons can further split into the pairs of tensor-gluons through a different channels. To describe all these processes one should know the general splitting probabilities for tensor-gluons. These probabilities should fulfill very general symmetry relations, which we were able to resolve by introducing a splitting index. This approach allows to find out the general form of the splitting functions, to derive corresponding DGLAP evolution equations and to calculate the one-loop Callan-Simanzik beta function for tensor-gluons of a given spin. Our results provide a nontrivial consistency check of the theory and of the Callan-Simanzik beta function calculations, because the theory has a unique coupling constant and its high energy behavior should be universal for all particles of the spectrum. We argue that the contribution of all spins into the beta function vanishes leading to a conformal invariant theory at very high energies.
0708.0260
Samoil Bilenky M.
S. M. Bilenky
Recoilless Resonance Absorption of Tritium Antineutrinos and Time-Energy Uncertainty Relation
null
null
null
null
hep-ph
null
We discuss neutrino oscillations in an experiment with M\"ossbauer recoilless resonance absorbtion of tritium antineutrinos, proposed recently by Raghavan. We demonstrate that small energy uncertainty of antineutrinos which ensures a large resonance absorption cross section is in a conflict with the energy uncertainty which, according to the time-energy uncertainty relation, is necessary for neutrino oscillations to happen. The search for neutrino oscillations in the M\"ossbauer neutrino experiment would be an important test of the applicability of the time-energy uncertainty relation to a newly discovered interference phenomenon.
[ { "created": "Thu, 2 Aug 2007 02:22:59 GMT", "version": "v1" } ]
2007-08-03
[ [ "Bilenky", "S. M.", "" ] ]
We discuss neutrino oscillations in an experiment with M\"ossbauer recoilless resonance absorbtion of tritium antineutrinos, proposed recently by Raghavan. We demonstrate that small energy uncertainty of antineutrinos which ensures a large resonance absorption cross section is in a conflict with the energy uncertainty which, according to the time-energy uncertainty relation, is necessary for neutrino oscillations to happen. The search for neutrino oscillations in the M\"ossbauer neutrino experiment would be an important test of the applicability of the time-energy uncertainty relation to a newly discovered interference phenomenon.
1203.1041
Stefania Gori
Marcela Carena, Stefania Gori, Aurelio Juste, Arjun Menon, Carlos E. M. Wagner, Lian-Tao Wang
LHC Discovery Potential for Non-Standard Higgs Bosons in the 3b Channel
14 pages, 3 figures, 4 tables, references added, published version
null
10.1007/JHEP07(2012)091
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In a variety of well motivated models, such as two Higgs Doublet Models (2HDMs) and the Minimal Supersymmetric Standard Model (MSSM), there are neutral Higgs bosons that have significantly enhanced couplings to b-quarks and tau leptons in comparison to those of the SM Higgs. These so called non-standard Higgs bosons could be copiously produced at the LHC in association with b quarks, and subsequently decay into b-quark pairs. However, this production channel suffers from large irreducible QCD backgrounds. We propose a new search strategy for non-standard neutral Higgs bosons at the 7 TeV LHC in the 3b's final state topology. We perform a simulation of the signal and backgrounds, using state of the art tools and methods for different sets of selection cuts, and conclude that neutral Higgs bosons with couplings to b-quarks of about 0.3 or larger, and masses up to 400 GeV, could be seen with a luminosity of 30 fb^{-1}. In the case of the MSSM we also discuss the complementarity between the 3b channel and the inclusive tau pair channel in exploring the supersymmetric parameter space.
[ { "created": "Mon, 5 Mar 2012 21:00:40 GMT", "version": "v1" }, { "created": "Thu, 28 Jun 2012 20:01:55 GMT", "version": "v2" } ]
2015-06-04
[ [ "Carena", "Marcela", "" ], [ "Gori", "Stefania", "" ], [ "Juste", "Aurelio", "" ], [ "Menon", "Arjun", "" ], [ "Wagner", "Carlos E. M.", "" ], [ "Wang", "Lian-Tao", "" ] ]
In a variety of well motivated models, such as two Higgs Doublet Models (2HDMs) and the Minimal Supersymmetric Standard Model (MSSM), there are neutral Higgs bosons that have significantly enhanced couplings to b-quarks and tau leptons in comparison to those of the SM Higgs. These so called non-standard Higgs bosons could be copiously produced at the LHC in association with b quarks, and subsequently decay into b-quark pairs. However, this production channel suffers from large irreducible QCD backgrounds. We propose a new search strategy for non-standard neutral Higgs bosons at the 7 TeV LHC in the 3b's final state topology. We perform a simulation of the signal and backgrounds, using state of the art tools and methods for different sets of selection cuts, and conclude that neutral Higgs bosons with couplings to b-quarks of about 0.3 or larger, and masses up to 400 GeV, could be seen with a luminosity of 30 fb^{-1}. In the case of the MSSM we also discuss the complementarity between the 3b channel and the inclusive tau pair channel in exploring the supersymmetric parameter space.
0805.4202
Ismail Turan
Durmus A. Demir (IZTECH and DESY), Mariana Frank (Concordia Univ.), Katri Huitu, Santosh K. Rai (Univ. of Helsinki), and Ismail Turan (Concordia Univ.)
Signals of Doubly-Charged Higgsinos at the CERN Large Hadron Collider
14 pages, two-column format, 13 figures, 1 table
Phys.Rev.D78:035013,2008
10.1103/PhysRevD.78.035013
DESY-08-060, IZTECH-P-08-03, CUMQ-HEP-149, HIP-2008-15/TH
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Several supersymmetric models with extended gauge structures, motivated by either grand unification or by neutrino mass generation, predict light doubly-charged Higgsinos. In this work we study productions and decays of doubly-charged Higgsinos present in left-right supersymmetric models, and show that they invariably lead to novel collider signals not found in the minimal supersymmetric model (MSSM) or in any of its extensions motivated by the \mu problem or even in extra dimensional theories. We investigate their distinctive signatures at the Large Hadron Collider (LHC) in both pair-- and single--production modes, and show that they are powerful tools in determining the underlying model via the measurements at the LHC experiments.
[ { "created": "Tue, 27 May 2008 20:24:23 GMT", "version": "v1" } ]
2008-11-26
[ [ "Demir", "Durmus A.", "", "IZTECH and DESY" ], [ "Frank", "Mariana", "", "Concordia Univ." ], [ "Huitu", "Katri", "", "Univ. of Helsinki" ], [ "Rai", "Santosh K.", "", "Univ. of Helsinki" ], [ "Turan", "Ismail", "", "Concordia\n Univ." ] ]
Several supersymmetric models with extended gauge structures, motivated by either grand unification or by neutrino mass generation, predict light doubly-charged Higgsinos. In this work we study productions and decays of doubly-charged Higgsinos present in left-right supersymmetric models, and show that they invariably lead to novel collider signals not found in the minimal supersymmetric model (MSSM) or in any of its extensions motivated by the \mu problem or even in extra dimensional theories. We investigate their distinctive signatures at the Large Hadron Collider (LHC) in both pair-- and single--production modes, and show that they are powerful tools in determining the underlying model via the measurements at the LHC experiments.
hep-ph/0306252
Mahadev Patgiri
Mahadev Patgiri and N. Nimai Singh
Inverted Hierarchical Model of Neutrino Masses Revisited
4pages (To appear in Physics Letters B
Phys.Lett. B567 (2003) 69-72
10.1016/j.physletb.2003.06.021
null
hep-ph
null
In this letter we highlight the inherent problems associted with the inverted hierarchical model of neutrinos with only three generations and suggest possible solutions within the MSSM. we discuss the new parametrisation of the solar mixing angle which can identify the light side and dark side of the data. We then argue whether the inverted hierarchical neutrino mass matrix can explain the large mixing angle(LMA) MSW solution of the solar neutrino anomaly in the presence of an appropriate texture of charged lepton mass matrix. In model independent way we explore such specific form of the charged lepton mass matrix having special structure in 1-2 block. The contribution to the solar mass splitting arising out of radiative corrections in MSSM, is calculated, thus making the model stable under radiative corrections.
[ { "created": "Wed, 25 Jun 2003 18:41:31 GMT", "version": "v1" } ]
2009-11-10
[ [ "Patgiri", "Mahadev", "" ], [ "Singh", "N. Nimai", "" ] ]
In this letter we highlight the inherent problems associted with the inverted hierarchical model of neutrinos with only three generations and suggest possible solutions within the MSSM. we discuss the new parametrisation of the solar mixing angle which can identify the light side and dark side of the data. We then argue whether the inverted hierarchical neutrino mass matrix can explain the large mixing angle(LMA) MSW solution of the solar neutrino anomaly in the presence of an appropriate texture of charged lepton mass matrix. In model independent way we explore such specific form of the charged lepton mass matrix having special structure in 1-2 block. The contribution to the solar mass splitting arising out of radiative corrections in MSSM, is calculated, thus making the model stable under radiative corrections.
hep-ph/0008315
Michael McNeil Forbes
Michael McNeil Forbes, Ariel R. Zhitnitsky (University of British Columbia, Canada)
Domain Walls in QCD
44 Pages (LaTeX JHEP), 8 Figures. Final Version. Improved explanations based on referee's comments
JHEP 0110:013,2001
10.1088/1126-6708/2001/10/013
null
hep-ph hep-th nucl-th
null
QCD was shown to have a nontrivial vacuum structure due to the topology of the theta = theta+2*pi*n parameter. As a result of this nontrivial topology, in the large N_c limit, quasi-stable QCD domain walls appear, characterized by a transition in the singlet eta' field. We discuss the physics of these QCD domain walls as well as related axion domain walls and we present a new type of axion wall which also contains an eta' transition. We argue that these domain walls are topologically stable in the limit N_c->infinity and classically stable for large but finite N_c, however, they can decay through a tunneling process. We argue that the qualitative features of these QCD domain walls -- namely their classical stability -- persist to the realistic case of N_c=3 and that it is at least possible that their lifetime could be macroscopically large. If it is, then QCD domain walls could play an important role in the evolution of early universe and may be detectable in energetic collisions such as those at the Relativistic Heavy Ion Collider (RHIC).
[ { "created": "Wed, 30 Aug 2000 17:54:28 GMT", "version": "v1" }, { "created": "Tue, 12 Jun 2001 23:26:22 GMT", "version": "v2" }, { "created": "Thu, 15 Nov 2001 00:30:17 GMT", "version": "v3" } ]
2010-02-03
[ [ "Forbes", "Michael McNeil", "", "University of British\n Columbia, Canada" ], [ "Zhitnitsky", "Ariel R.", "", "University of British\n Columbia, Canada" ] ]
QCD was shown to have a nontrivial vacuum structure due to the topology of the theta = theta+2*pi*n parameter. As a result of this nontrivial topology, in the large N_c limit, quasi-stable QCD domain walls appear, characterized by a transition in the singlet eta' field. We discuss the physics of these QCD domain walls as well as related axion domain walls and we present a new type of axion wall which also contains an eta' transition. We argue that these domain walls are topologically stable in the limit N_c->infinity and classically stable for large but finite N_c, however, they can decay through a tunneling process. We argue that the qualitative features of these QCD domain walls -- namely their classical stability -- persist to the realistic case of N_c=3 and that it is at least possible that their lifetime could be macroscopically large. If it is, then QCD domain walls could play an important role in the evolution of early universe and may be detectable in energetic collisions such as those at the Relativistic Heavy Ion Collider (RHIC).
hep-ph/9712512
Stephen Parke
Stephen Parke (Fermi National Accelerator Laboratory)
Top Quark Physics: Overview
15 pages, 12 figures, Latex, sprocl.sty presentation at the International Symposium on ``QCD Corrections and New Physics'' October 27-29, 1997 held at Hiroshima, Japan
null
null
FERMILAB-Conf-97/431-T
hep-ph
null
In this presentation I will primarily focus on top quark physics but I will include a discussion of the W-boson mass and the possibility of discovering a light Higgs boson via associated production at the Tevatron.
[ { "created": "Tue, 23 Dec 1997 18:18:05 GMT", "version": "v1" } ]
2007-05-23
[ [ "Parke", "Stephen", "", "Fermi National Accelerator Laboratory" ] ]
In this presentation I will primarily focus on top quark physics but I will include a discussion of the W-boson mass and the possibility of discovering a light Higgs boson via associated production at the Tevatron.
1508.07078
Koji Ichikawa
Takeshi Fukuyama, Koji Ichikawa and Yukihiro Mimura
Revisiting fermion mass and mixing fits in the minimal SUSY $SO(10)$ GUT
This is the version to be published in Phys.Rev.D. The old subsection of proton decay is discussed in a separate form, arXiv:1609.08640
Phys. Rev. D 94, 075018 (2016)
10.1103/PhysRevD.94.075018
IPMU15-0141
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Supersymmetric $SO(10)$ grand unified models with renormalizable Yukawa couplings involving only ${\bf 10}$ and $\overline{\bf 126}$ Higgs fields have been shown to realize the fermion masses and mixings economically. In previous works, the sum rule of the fermion mass matrices are given by inputting the quark matrices, and the neutrino mixings are predicted in this framework. Now the three neutrino mixings have been measured, and in this paper, we give the sum rule by inputting the lepton mass matrices, which makes clear certain features of the solution, especially if the vacuum expectation values of ${\bf 126}+ \overline{\bf126}$ ($v_R$) are large and the right-handed neutrinos are heavy. We perform the $\chi^2$ analyses to fit the fermion masses and mixings using the sum rule. In previous works, the best fit appears at $v_R \sim 10^{13}$ GeV, and the fit at the large $v_R$ scale ($\sim 10^{16}$ GeV) has been less investigated. Our expression of the sum rule has a benefit to understand the flavor structure in the large $v_R$ solution. Using the fit results, we perform the calculation of the $\mu \to e\gamma$ process and the electric dipole moment of electron, and the importance of $v_R$ dependence emerges in low energy phenomena. We also show the prediction of the CP phase in the neutrino oscillations, which can be tested in the near future.
[ { "created": "Fri, 28 Aug 2015 02:54:23 GMT", "version": "v1" }, { "created": "Tue, 11 Oct 2016 11:05:42 GMT", "version": "v2" } ]
2016-11-02
[ [ "Fukuyama", "Takeshi", "" ], [ "Ichikawa", "Koji", "" ], [ "Mimura", "Yukihiro", "" ] ]
Supersymmetric $SO(10)$ grand unified models with renormalizable Yukawa couplings involving only ${\bf 10}$ and $\overline{\bf 126}$ Higgs fields have been shown to realize the fermion masses and mixings economically. In previous works, the sum rule of the fermion mass matrices are given by inputting the quark matrices, and the neutrino mixings are predicted in this framework. Now the three neutrino mixings have been measured, and in this paper, we give the sum rule by inputting the lepton mass matrices, which makes clear certain features of the solution, especially if the vacuum expectation values of ${\bf 126}+ \overline{\bf126}$ ($v_R$) are large and the right-handed neutrinos are heavy. We perform the $\chi^2$ analyses to fit the fermion masses and mixings using the sum rule. In previous works, the best fit appears at $v_R \sim 10^{13}$ GeV, and the fit at the large $v_R$ scale ($\sim 10^{16}$ GeV) has been less investigated. Our expression of the sum rule has a benefit to understand the flavor structure in the large $v_R$ solution. Using the fit results, we perform the calculation of the $\mu \to e\gamma$ process and the electric dipole moment of electron, and the importance of $v_R$ dependence emerges in low energy phenomena. We also show the prediction of the CP phase in the neutrino oscillations, which can be tested in the near future.
1506.08003
Motohiko Yoshimura
M. Yoshimura and N. Sasao
Determination of CP violation parameter using neutrino pair beam
9 pages, 6 figures
null
10.1016/j.physletb.2015.12.040
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Neutrino oscillation experiments under neutrino pair beam from circulating excited heavy ions are studied. It is found that detection of double weak events has a good sensitivity to measure CP violating parameter and distinguish mass hierarchy patterns in short baseline experiments in which the earth-induced matter effect is minimized.
[ { "created": "Fri, 26 Jun 2015 09:10:14 GMT", "version": "v1" } ]
2015-12-23
[ [ "Yoshimura", "M.", "" ], [ "Sasao", "N.", "" ] ]
Neutrino oscillation experiments under neutrino pair beam from circulating excited heavy ions are studied. It is found that detection of double weak events has a good sensitivity to measure CP violating parameter and distinguish mass hierarchy patterns in short baseline experiments in which the earth-induced matter effect is minimized.
1408.1627
Gudrun Hiller
Gudrun Hiller, Martin Schmaltz
$R_K$ and future $b \to s \ell \ell$ BSM opportunities
8 pages
Phys. Rev. D 90, 054014 (2014)
10.1103/PhysRevD.90.054014
DO-TH 14/17
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Flavor changing neutral current $|\Delta B|=|\Delta S|=1$ processes are sensitive to possible new physics at the electroweak scale and beyond, providing detailed information about flavor, chirality and Lorentz structure. Recently the LHCb collaboration announced a $2.6 \sigma$ deviation in the measurement of $R_K={\cal{B}}(\bar B \to \bar K \mu \mu)/{\cal{B}}(\bar B \to \bar K ee)$ from the standard model's prediction of lepton universality. We identify dimension six operators which could explain this deviation and study constraints from other measurements. Vector and axial-vector four-fermion operators with flavor structure $\bar s b \bar \ell \ell$ can provide a good description of the data. Tensor operators cannot describe the data. Pseudo-scalar and scalar operators only fit the data with some fine-tuning; they can be further probed with the $\bar B \to \bar K ee$ angular distribution. The data appears to point towards $C_9^{\rm NP \mu} = -C_{10}^{\rm NP \mu }<0$, an $SU(2)_{L}$ invariant direction in parameter space supported by $R_K$, the $\bar B \to \bar K^* \mu \mu$ forward-backward asymmetry and the $\bar B_s \to \mu \mu$ branching ratio, which is currently allowed to be smaller than the standard model prediction. We present two leptoquark models which can explain the FCNC data and give predictions for the LHC and rare decays.
[ { "created": "Thu, 7 Aug 2014 15:45:17 GMT", "version": "v1" } ]
2014-09-24
[ [ "Hiller", "Gudrun", "" ], [ "Schmaltz", "Martin", "" ] ]
Flavor changing neutral current $|\Delta B|=|\Delta S|=1$ processes are sensitive to possible new physics at the electroweak scale and beyond, providing detailed information about flavor, chirality and Lorentz structure. Recently the LHCb collaboration announced a $2.6 \sigma$ deviation in the measurement of $R_K={\cal{B}}(\bar B \to \bar K \mu \mu)/{\cal{B}}(\bar B \to \bar K ee)$ from the standard model's prediction of lepton universality. We identify dimension six operators which could explain this deviation and study constraints from other measurements. Vector and axial-vector four-fermion operators with flavor structure $\bar s b \bar \ell \ell$ can provide a good description of the data. Tensor operators cannot describe the data. Pseudo-scalar and scalar operators only fit the data with some fine-tuning; they can be further probed with the $\bar B \to \bar K ee$ angular distribution. The data appears to point towards $C_9^{\rm NP \mu} = -C_{10}^{\rm NP \mu }<0$, an $SU(2)_{L}$ invariant direction in parameter space supported by $R_K$, the $\bar B \to \bar K^* \mu \mu$ forward-backward asymmetry and the $\bar B_s \to \mu \mu$ branching ratio, which is currently allowed to be smaller than the standard model prediction. We present two leptoquark models which can explain the FCNC data and give predictions for the LHC and rare decays.
hep-ph/9805452
Yan Hua-gang
Chao-Shang Huang, Cong-Feng Qiao, and Hua-Gang Yan
Decay $\Lambda_b \to p l \bar \nu$ in QCD sum rules
6 pages Latex file, 4 figures, corrected file forms
Phys.Lett. B437 (1998) 403-407
10.1016/S0370-2693(98)00909-5
null
hep-ph
null
The $\Lambda_b \to p$ semileptonic decay is analyzed by using QCD sum rules within the framework of heavy quark effective theory. The Isgur-Wise function of $\Lambda_b \to p l \bar\nu$ has been calculated. The decay width is given.
[ { "created": "Tue, 26 May 1998 02:15:04 GMT", "version": "v1" }, { "created": "Fri, 24 Jul 1998 01:32:19 GMT", "version": "v2" }, { "created": "Fri, 14 Aug 1998 04:02:23 GMT", "version": "v3" } ]
2009-10-31
[ [ "Huang", "Chao-Shang", "" ], [ "Qiao", "Cong-Feng", "" ], [ "Yan", "Hua-Gang", "" ] ]
The $\Lambda_b \to p$ semileptonic decay is analyzed by using QCD sum rules within the framework of heavy quark effective theory. The Isgur-Wise function of $\Lambda_b \to p l \bar\nu$ has been calculated. The decay width is given.
0910.1642
Toshitaka Tatsumi
T. Tatsumi
Ferromagnetic properties of quark matter -an origin of magnetic field in compact stars-
to appear in Proc. of CSQCD II
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Magnetic properties of quark matter are studied within the Landau Fermi-liquid theory, and magnetic phase diagram of QCD is presented in the density-temperature plane. The screening effect for gluon propagator is emphasized to see the characteristic behavior of the magnetic susceptibility; novel non-Fermi-liquid behavior is observed at finite temperature. Some implications on the origin of the magnetic field in compact stars, especially magnetars, are briefly discussed.
[ { "created": "Fri, 9 Oct 2009 02:25:59 GMT", "version": "v1" } ]
2009-10-12
[ [ "Tatsumi", "T.", "" ] ]
Magnetic properties of quark matter are studied within the Landau Fermi-liquid theory, and magnetic phase diagram of QCD is presented in the density-temperature plane. The screening effect for gluon propagator is emphasized to see the characteristic behavior of the magnetic susceptibility; novel non-Fermi-liquid behavior is observed at finite temperature. Some implications on the origin of the magnetic field in compact stars, especially magnetars, are briefly discussed.
1006.3846
Chaehyun Yu
P. Ko, Chaehyun Yu (KIAS), Jungil Lee (Korea U.)
p p -> J/psi+Upsilon+X as a clean probe to the quarkonium production mechanism
5 pages, 3 figures, version published in Phys. Rev. D
Phys.Rev.D83:054015,2011
10.1103/PhysRevD.83.054015
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We report that, unlike most inclusive quarkonium-production processes, the production rate for p p -> J/psi+Upsilon+X dominantly depends on two not well-known long-distance nonrelativistic QCD matrix elements, <O_8^{J/psi}(^3S_1)> and <O_8^{Upsilon}(^3S_1)> at leading order in the strong coupling constant, which account for the transition probabilities of the color-octet spin-triplet heavy-quark-antiquark pairs c\bar{c}_8(^3S_1) -> J/psi and b\bar{b}_8(^3S_1) -> Upsilon, respectively. With the integrated luminosity ~ 100 fb^{-1} at the center-of-momentum energy sqrt{s}=14 TeV we expect that approximately 1900 p p -> J/psi+Upsilon+X events can be observed at the CERN Large Hadron Collider by tagging muon pairs, which are enough to probe to the color-octet mechanism. The forthcoming measurement may provide a useful constraint to resolve the decade-old puzzle for the polarization of prompt J/psi at the Fermilab Tevatron. If corresponding measured rate is significantly less than the prediction, it may imply that the current values for the color-octet matrix elements are overestimated.
[ { "created": "Sat, 19 Jun 2010 07:11:24 GMT", "version": "v1" }, { "created": "Mon, 14 Mar 2011 05:52:48 GMT", "version": "v2" } ]
2011-03-22
[ [ "Ko", "P.", "", "KIAS" ], [ "Yu", "Chaehyun", "", "KIAS" ], [ "Lee", "Jungil", "", "Korea U." ] ]
We report that, unlike most inclusive quarkonium-production processes, the production rate for p p -> J/psi+Upsilon+X dominantly depends on two not well-known long-distance nonrelativistic QCD matrix elements, <O_8^{J/psi}(^3S_1)> and <O_8^{Upsilon}(^3S_1)> at leading order in the strong coupling constant, which account for the transition probabilities of the color-octet spin-triplet heavy-quark-antiquark pairs c\bar{c}_8(^3S_1) -> J/psi and b\bar{b}_8(^3S_1) -> Upsilon, respectively. With the integrated luminosity ~ 100 fb^{-1} at the center-of-momentum energy sqrt{s}=14 TeV we expect that approximately 1900 p p -> J/psi+Upsilon+X events can be observed at the CERN Large Hadron Collider by tagging muon pairs, which are enough to probe to the color-octet mechanism. The forthcoming measurement may provide a useful constraint to resolve the decade-old puzzle for the polarization of prompt J/psi at the Fermilab Tevatron. If corresponding measured rate is significantly less than the prediction, it may imply that the current values for the color-octet matrix elements are overestimated.
1801.03927
Umit Kaya
U. Kaya and S. Sultansoy
Mass Pattern of the SM Fermions: Flavor Democracy Revisited
8 pages, 2 Table. arXiv admin note: text overlap with arXiv:1607.07623
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Mass pattern of the SM fermions is one of the most important mysterious in particle physics. Flavor Democracy could shed light on this mystery. Addition of isosinglet quark and isosinglet lepton give opportunity to obtain masses of charged leptons and quarks of the 2nd and 3rd family due to small deviations of full Flavor Democracy.
[ { "created": "Wed, 10 Jan 2018 20:04:44 GMT", "version": "v1" } ]
2018-01-15
[ [ "Kaya", "U.", "" ], [ "Sultansoy", "S.", "" ] ]
Mass pattern of the SM fermions is one of the most important mysterious in particle physics. Flavor Democracy could shed light on this mystery. Addition of isosinglet quark and isosinglet lepton give opportunity to obtain masses of charged leptons and quarks of the 2nd and 3rd family due to small deviations of full Flavor Democracy.
0704.3981
Stephen West
Ben Gripaios and Stephen M. West
Anomaly Holography
26 pages, references added
Nucl.Phys.B789:362-381,2008
10.1016/j.nuclphysb.2007.08.008
OUTP-0705P
hep-ph hep-th
null
We consider, in the effective field theory context, anomalies of gauge field theories on a slice of a five-dimensional, Anti-de Sitter geometry and their four-dimensional, holographic duals. A consistent effective field theory description can always be found, notwithstanding the presence of the anomalies and without modifying the degrees of freedom of the theory. If anomalies do not vanish, the d=4 theory contains additional pseudoscalar states, which are either present in the low-energy theory as physical, light states, or are eaten by (would-be massless) gauge bosons. We show that the pseudoscalars ensure that global anomalies of the four-dimensional dual satisfy the 't Hooft matching condition and comment on the relevance for warped models of electroweak symmetry breaking.
[ { "created": "Mon, 30 Apr 2007 17:22:35 GMT", "version": "v1" }, { "created": "Thu, 14 Feb 2008 10:46:30 GMT", "version": "v2" } ]
2008-11-26
[ [ "Gripaios", "Ben", "" ], [ "West", "Stephen M.", "" ] ]
We consider, in the effective field theory context, anomalies of gauge field theories on a slice of a five-dimensional, Anti-de Sitter geometry and their four-dimensional, holographic duals. A consistent effective field theory description can always be found, notwithstanding the presence of the anomalies and without modifying the degrees of freedom of the theory. If anomalies do not vanish, the d=4 theory contains additional pseudoscalar states, which are either present in the low-energy theory as physical, light states, or are eaten by (would-be massless) gauge bosons. We show that the pseudoscalars ensure that global anomalies of the four-dimensional dual satisfy the 't Hooft matching condition and comment on the relevance for warped models of electroweak symmetry breaking.
1008.3886
Wolfgang Bietenholz
Wolfgang Bietenholz
The Photon Dispersion as an Indicator for New Physics ?
8 pages, 4 figures, talk presented at the VI International Workshop on the Dark Side of the Universe, Leon (Mexico), June 1-6, 2010. References added
J.Phys.Conf.Ser.315:012029,2011
10.1088/1742-6596/315/1/012029
null
hep-ph astro-ph.HE hep-lat hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We first comment on the search for a deviation from the linear photon dispersion relation, in particular based on cosmic photons from Gamma Ray Bursts. Then we consider the non-commutative space as a theoretical concept that could lead to such a deviation, which would be a manifestation of Lorentz Invariance Violation. In particular we review a numerical study of pure U(1) gauge theory in a 4d non-commutative space. Starting from a finite lattice, we explore the phase diagram and the extrapolation to the continuum and infinite volume. These simultaneous limits - taken at fixed non-commutativity - lead to a phase of broken Poincare symmetry, where the photon appears to be IR stable, despite a negative IR divergence to one loop.
[ { "created": "Mon, 23 Aug 2010 18:57:47 GMT", "version": "v1" }, { "created": "Thu, 2 Sep 2010 18:40:08 GMT", "version": "v2" } ]
2011-08-25
[ [ "Bietenholz", "Wolfgang", "" ] ]
We first comment on the search for a deviation from the linear photon dispersion relation, in particular based on cosmic photons from Gamma Ray Bursts. Then we consider the non-commutative space as a theoretical concept that could lead to such a deviation, which would be a manifestation of Lorentz Invariance Violation. In particular we review a numerical study of pure U(1) gauge theory in a 4d non-commutative space. Starting from a finite lattice, we explore the phase diagram and the extrapolation to the continuum and infinite volume. These simultaneous limits - taken at fixed non-commutativity - lead to a phase of broken Poincare symmetry, where the photon appears to be IR stable, despite a negative IR divergence to one loop.
1908.03755
Lei Wang
Lei Wang, Yang Zhang
A $\mu$-$\tau$-philic Higgs doublet confronted with the muon g-2, $\tau$ decays and LHC data
15 pages, 3 figures
Phys. Rev. D 100, 095005 (2019)
10.1103/PhysRevD.100.095005
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose a two-Higgs-doublet model in which one Higgs doublet has the same interactions with fermions as the SM, and another Higgs doublet only has the $\mu$-$\tau$ LFV interactions. Assuming that the Yukawa matrices are real and symmetric, we impose various relevant theoretical and experimental constraints, and find that the excesses of muon $g-2$ and lepton flavour universality in the $\tau$ decays can be simultaneously explained in the region of small mass splittings between the heavy CP-even Higgs and the CP-odd Higgs ($m_A > m_H$). The multi-lepton event searches at the LHC can sizably reduce the mass ranges of extra Higgses, and $m_H$ is required to be larger than 560 GeV.
[ { "created": "Sat, 10 Aug 2019 13:49:18 GMT", "version": "v1" }, { "created": "Thu, 8 Apr 2021 03:20:48 GMT", "version": "v2" } ]
2021-04-09
[ [ "Wang", "Lei", "" ], [ "Zhang", "Yang", "" ] ]
We propose a two-Higgs-doublet model in which one Higgs doublet has the same interactions with fermions as the SM, and another Higgs doublet only has the $\mu$-$\tau$ LFV interactions. Assuming that the Yukawa matrices are real and symmetric, we impose various relevant theoretical and experimental constraints, and find that the excesses of muon $g-2$ and lepton flavour universality in the $\tau$ decays can be simultaneously explained in the region of small mass splittings between the heavy CP-even Higgs and the CP-odd Higgs ($m_A > m_H$). The multi-lepton event searches at the LHC can sizably reduce the mass ranges of extra Higgses, and $m_H$ is required to be larger than 560 GeV.
1106.4697
Imrich Zborovsky
I. Zborovsk\'y
Multiplicity distributions in proton-(anti)proton and electron-positron collisions with parton recombination
20 pages, 14 figures, 6 tables
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A new approach to phenomenological description of the charged particle multiplicity distributions in proton-(anti)proton and electron-positron collisions is presented. The observed features of the data are interpreted on the basis of stochastic-physical ideas of multiple production. Besides the processes of parton immigration and absorption, two and three patron incremental and decremental recombinations are considered. The complex behaviour of the multiplicity distributions at different energies is described by four parametric generalized hypergeometric distribution (GHD). Application of the proposed GHD to data measured by the CMS, ALICE, and ATLAS Collaborations suggests that soft multiparton recombination processes can manifest itself significantly in the structure of multiplicity distribution in pp interactions at very high energies.
[ { "created": "Thu, 23 Jun 2011 12:28:46 GMT", "version": "v1" } ]
2011-06-24
[ [ "Zborovský", "I.", "" ] ]
A new approach to phenomenological description of the charged particle multiplicity distributions in proton-(anti)proton and electron-positron collisions is presented. The observed features of the data are interpreted on the basis of stochastic-physical ideas of multiple production. Besides the processes of parton immigration and absorption, two and three patron incremental and decremental recombinations are considered. The complex behaviour of the multiplicity distributions at different energies is described by four parametric generalized hypergeometric distribution (GHD). Application of the proposed GHD to data measured by the CMS, ALICE, and ATLAS Collaborations suggests that soft multiparton recombination processes can manifest itself significantly in the structure of multiplicity distribution in pp interactions at very high energies.
hep-ph/0602057
Vladimir Kuksa
V.I. Kuksa
The convolution model of unstable particles
11 pages, added reference, changed content
null
null
null
hep-ph
null
Quantum field model of unstable particles with random mass is suggested to describe the finite-width effects in decay rate. Within the framework of this model we derive the convolution formula for a width of the channels with unstable particle in a final state. The distribution function of random mass is considered for ustable particles of arbitrary type
[ { "created": "Tue, 7 Feb 2006 07:20:02 GMT", "version": "v1" }, { "created": "Tue, 27 Jun 2006 05:42:08 GMT", "version": "v2" } ]
2007-05-23
[ [ "Kuksa", "V. I.", "" ] ]
Quantum field model of unstable particles with random mass is suggested to describe the finite-width effects in decay rate. Within the framework of this model we derive the convolution formula for a width of the channels with unstable particle in a final state. The distribution function of random mass is considered for ustable particles of arbitrary type
1603.09621
Eugene Zabrodin
J. Crkovska, J. Bielcik, L. Bravina, B.H. Brusheim Johansson, E. Zabrodin, G. Eyyubova, V.L. Korotkikh, I.P. Lokhtin, L.V. Malinina, S.V. Petrushanko, A.M. Snigirev
Influence of jets and decays of resonances on the triangular flow in ultrarelativistic heavy-ion collisions
revised version
Phys. Rev. C 95 (2017) 014910
10.1103/PhysRevC.95.014910
null
hep-ph nucl-ex nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Triangular flow $v_3$ of identified and inclusive particles in Pb+Pb collisions at $\sqrt{s_{NN}} = 2.76$ TeV is studied as a function of centrality and transverse momentum within the \textsc{hydjet++} model. The model enables one to investigate the influence of both hard processes and final-state interactions on the harmonics of particle anisotropic flow. Decays of resonances are found to increase the magnitude of the $v_3(p_{\rm T})$ distributions at $p_{\rm T} \geq 2$ GeV/$c$ and shift their maxima to higher transverse momenta. The $p_{\rm T}$-integrated triangular flow, however, becomes slightly weakened for all centralities studied. The resonance decays also modify the spectra towards the number-of-constituent-quark scaling fulfillment for the triangular flow, whereas jets are the main source of the scaling violation at the energies available at the CERN Large Hadron Collider (LHC). Comparison with the corresponding spectra of elliptic flow reveals that resonance decays and jets act in a similar manner on both $v_3(p_{\rm T})$ and $v_2(p_{\rm T})$ behavior. Obtained results are also confronted with the experimental data on differential triangular flow of identified hadrons, ratio $v_3^{1/3}(p_{\rm T}) / v_2^{1/2}(p_{\rm T})$ and $p_{\rm T}$-integrated triangular flow of charged hadrons.
[ { "created": "Thu, 31 Mar 2016 15:01:20 GMT", "version": "v1" }, { "created": "Wed, 25 Jan 2017 17:26:06 GMT", "version": "v2" } ]
2017-01-26
[ [ "Crkovska", "J.", "" ], [ "Bielcik", "J.", "" ], [ "Bravina", "L.", "" ], [ "Johansson", "B. H. Brusheim", "" ], [ "Zabrodin", "E.", "" ], [ "Eyyubova", "G.", "" ], [ "Korotkikh", "V. L.", "" ], [ "Lokhtin", "I. P.", "" ], [ "Malinina", "L. V.", "" ], [ "Petrushanko", "S. V.", "" ], [ "Snigirev", "A. M.", "" ] ]
Triangular flow $v_3$ of identified and inclusive particles in Pb+Pb collisions at $\sqrt{s_{NN}} = 2.76$ TeV is studied as a function of centrality and transverse momentum within the \textsc{hydjet++} model. The model enables one to investigate the influence of both hard processes and final-state interactions on the harmonics of particle anisotropic flow. Decays of resonances are found to increase the magnitude of the $v_3(p_{\rm T})$ distributions at $p_{\rm T} \geq 2$ GeV/$c$ and shift their maxima to higher transverse momenta. The $p_{\rm T}$-integrated triangular flow, however, becomes slightly weakened for all centralities studied. The resonance decays also modify the spectra towards the number-of-constituent-quark scaling fulfillment for the triangular flow, whereas jets are the main source of the scaling violation at the energies available at the CERN Large Hadron Collider (LHC). Comparison with the corresponding spectra of elliptic flow reveals that resonance decays and jets act in a similar manner on both $v_3(p_{\rm T})$ and $v_2(p_{\rm T})$ behavior. Obtained results are also confronted with the experimental data on differential triangular flow of identified hadrons, ratio $v_3^{1/3}(p_{\rm T}) / v_2^{1/2}(p_{\rm T})$ and $p_{\rm T}$-integrated triangular flow of charged hadrons.
hep-ph/9909207
null
D. Falcone
Neutrino masses and mixings in a seesaw framework
13 pages RevTex, no figures. Revised version
Phys.Rev. D61 (2000) 097302
10.1103/PhysRevD.61.097302
DSF-T-99/30
hep-ph
null
Assuming the seesaw mechanism for hierarchical neutrino masses, we calculate the heavy neutrino masses under the hypotheses that the mixing in the Dirac leptonic sector is similar to the quark mixing ($V_D \sim V_{CKM}$) and that $M_{\nu} \sim M_u$ or $M_e$, where $M_{\nu}$ is the Dirac mass matrix of neutrinos. As a result we find that for $M_{\nu} \sim M_u$ the vacuum oscillation solution of the solar neutrino problem leads to a scale for the heavy neutrino mass well above the unification scale, while for the MSW solutions there is agreement with this scale. For $M_{\nu} \sim M_e$ the vacuum solution is consistent with the unification scale, and the MSW solutions with an intermediate scale. The mass of the lightest heavy neutrino can be as small as $10^5$ GeV.
[ { "created": "Wed, 1 Sep 1999 09:57:59 GMT", "version": "v1" }, { "created": "Fri, 26 Nov 1999 09:11:17 GMT", "version": "v2" } ]
2009-10-31
[ [ "Falcone", "D.", "" ] ]
Assuming the seesaw mechanism for hierarchical neutrino masses, we calculate the heavy neutrino masses under the hypotheses that the mixing in the Dirac leptonic sector is similar to the quark mixing ($V_D \sim V_{CKM}$) and that $M_{\nu} \sim M_u$ or $M_e$, where $M_{\nu}$ is the Dirac mass matrix of neutrinos. As a result we find that for $M_{\nu} \sim M_u$ the vacuum oscillation solution of the solar neutrino problem leads to a scale for the heavy neutrino mass well above the unification scale, while for the MSW solutions there is agreement with this scale. For $M_{\nu} \sim M_e$ the vacuum solution is consistent with the unification scale, and the MSW solutions with an intermediate scale. The mass of the lightest heavy neutrino can be as small as $10^5$ GeV.
hep-ph/9401320
Simonov
Yu.A.Simonov
Chiral Effects in the Confining QCD Vacuum
40 pages, preprint ITEP-83-93
Phys.Atom.Nucl.57:1418-1433,1994; Yad.Fiz.57:1491-1506,1994
null
null
hep-ph
null
Confining configurations are introduced into the standard instanton vacuum model. This drastically improves theoretical properties of the vacuum: instanton size density $d(\rho)$ stabilizes at $\rho\sim 0.2 fm$, all chiral effects are formulated in a gauge-invariant way and quarks are confined. An interesting interplay of chiral and confining dynamics is observed; for the realistic values of parameters the Georgi-Manohar picture emerges with chiral radius $R_{ch}\sim \rho\sim 0.2 fm$ much less than confining radius $R_c\sim$ hadron radius $\sim 1 fm$. In the limit $R_{ch}\ll R_c$ the chiral mass $M_{ch}(p)$ is unaffected by confinement and can be taken in the local limit $M_{ch}(p=0)$. Different types of effective chiral Lagrangians (ECL) are obtained, containing all or a part of gluon, quark and Nambu--Goldstone--meson fields. The ECL are manifestly gauge--invariant and in the limit of no gluon fields coincide with those found previously. The problem of the double role of the pion -- as a Goldstone meson or as a $q\bar{q}$ system is briefly disscussed using confining ECL with quarks, mesons and gluons.
[ { "created": "Tue, 25 Jan 1994 09:47:00 GMT", "version": "v1" } ]
2009-07-28
[ [ "Simonov", "Yu. A.", "" ] ]
Confining configurations are introduced into the standard instanton vacuum model. This drastically improves theoretical properties of the vacuum: instanton size density $d(\rho)$ stabilizes at $\rho\sim 0.2 fm$, all chiral effects are formulated in a gauge-invariant way and quarks are confined. An interesting interplay of chiral and confining dynamics is observed; for the realistic values of parameters the Georgi-Manohar picture emerges with chiral radius $R_{ch}\sim \rho\sim 0.2 fm$ much less than confining radius $R_c\sim$ hadron radius $\sim 1 fm$. In the limit $R_{ch}\ll R_c$ the chiral mass $M_{ch}(p)$ is unaffected by confinement and can be taken in the local limit $M_{ch}(p=0)$. Different types of effective chiral Lagrangians (ECL) are obtained, containing all or a part of gluon, quark and Nambu--Goldstone--meson fields. The ECL are manifestly gauge--invariant and in the limit of no gluon fields coincide with those found previously. The problem of the double role of the pion -- as a Goldstone meson or as a $q\bar{q}$ system is briefly disscussed using confining ECL with quarks, mesons and gluons.
2301.06621
Timo K\"arkk\"ainen
Timo J. K\"arkk\"ainen, Zolt\'an Tr\'ocs\'anyi
Constraining flavour-universal nonstandard interactions and superweak extension of the standard model
23 pages, 10 pictures. The version approved for publication in PRD
null
10.1103/PhysRevD.107.115020
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
Nonstandard neutrino interactions (NSI) arising from light and heavy mediators probe different sectors of the parameter space of models focusing on phenomena that require the extension of the standard model. High-energy scattering experiments are not relevant on constraining the NSI hiding a light mediator at the fundamental level, while flavour-universal NSI cannot be probed with neutrino oscillation experiments. Currently the only way to measure flavour-universal NSI with a light mediator is to rely on coherent elastic neutrino-nucleon scattering experiments, which we use to derive bounds for light mediator flavour-universal NSI. For light NSI, we obtain $\varepsilon^u \in [-14.85,14.79]$ and $\varepsilon^d \in [-13.19,13.84]$ (90~\% CL.). We also derive constraints on flavour-universal heavy NSI and find a 2$\sigma$ tension. Finally, we discuss the implications of the experiments on the allowed parameter space of a specific example model, called superweak extension of the standard model.
[ { "created": "Mon, 16 Jan 2023 21:59:56 GMT", "version": "v1" }, { "created": "Tue, 23 May 2023 13:05:37 GMT", "version": "v2" } ]
2023-06-28
[ [ "Kärkkäinen", "Timo J.", "" ], [ "Trócsányi", "Zoltán", "" ] ]
Nonstandard neutrino interactions (NSI) arising from light and heavy mediators probe different sectors of the parameter space of models focusing on phenomena that require the extension of the standard model. High-energy scattering experiments are not relevant on constraining the NSI hiding a light mediator at the fundamental level, while flavour-universal NSI cannot be probed with neutrino oscillation experiments. Currently the only way to measure flavour-universal NSI with a light mediator is to rely on coherent elastic neutrino-nucleon scattering experiments, which we use to derive bounds for light mediator flavour-universal NSI. For light NSI, we obtain $\varepsilon^u \in [-14.85,14.79]$ and $\varepsilon^d \in [-13.19,13.84]$ (90~\% CL.). We also derive constraints on flavour-universal heavy NSI and find a 2$\sigma$ tension. Finally, we discuss the implications of the experiments on the allowed parameter space of a specific example model, called superweak extension of the standard model.
1705.07745
Zhi-Gang Wang
Zhi-Gang Wang
Analysis of the $\Lambda_c(2860)$, $\Lambda_c(2880)$, $\Xi_c(3055)$ and $\Xi_c(3080)$ as D-wave baryon states with QCD sum rules
26 pages, 25 figures
Nucl. Phys. B926 (2018) 467-490
10.1016/j.nuclphysb.2017.11.014
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this article, we tentatively assign the $\Lambda_c(2860)$, $\Lambda_c(2880)$, $\Xi_c(3055)$ and $\Xi_c(3080)$ to be the D-wave baryon states with the spin-parity $J^P={\frac{3}{2}}^+$, ${\frac{5}{2}}^+$, ${\frac{3}{2}}^+$ and ${\frac{5}{2}}^+$, respectively, and study their masses and pole residues with the QCD sum rules in a systematic way by constructing three-types interpolating currents with the quantum numbers $(L_\rho,L_\lambda)=(0,2)$, $(2,0)$ and $(1,1)$, respectively. The present predictions favor assigning the $\Lambda_c(2860)$, $\Lambda_c(2880)$, $\Xi_c(3055)$ and $\Xi_c(3080)$ to be the D-wave baryon states with the quantum numbers $(L_\rho,L_\lambda)=(0,2)$ and $J^P={\frac{3}{2}}^+$, ${\frac{5}{2}}^+$, ${\frac{3}{2}}^+$ and ${\frac{5}{2}}^+$, respectively. While the predictions for the masses of the $(L_\rho,L_\lambda)=(2,0)$ and $(1,1)$ D-wave $\Lambda_c$ and $\Xi_c$ states can be confronted to the experimental data in the future.
[ { "created": "Fri, 19 May 2017 14:39:13 GMT", "version": "v1" }, { "created": "Sun, 18 Jun 2017 03:59:40 GMT", "version": "v2" }, { "created": "Thu, 19 Oct 2017 01:29:41 GMT", "version": "v3" } ]
2017-12-05
[ [ "Wang", "Zhi-Gang", "" ] ]
In this article, we tentatively assign the $\Lambda_c(2860)$, $\Lambda_c(2880)$, $\Xi_c(3055)$ and $\Xi_c(3080)$ to be the D-wave baryon states with the spin-parity $J^P={\frac{3}{2}}^+$, ${\frac{5}{2}}^+$, ${\frac{3}{2}}^+$ and ${\frac{5}{2}}^+$, respectively, and study their masses and pole residues with the QCD sum rules in a systematic way by constructing three-types interpolating currents with the quantum numbers $(L_\rho,L_\lambda)=(0,2)$, $(2,0)$ and $(1,1)$, respectively. The present predictions favor assigning the $\Lambda_c(2860)$, $\Lambda_c(2880)$, $\Xi_c(3055)$ and $\Xi_c(3080)$ to be the D-wave baryon states with the quantum numbers $(L_\rho,L_\lambda)=(0,2)$ and $J^P={\frac{3}{2}}^+$, ${\frac{5}{2}}^+$, ${\frac{3}{2}}^+$ and ${\frac{5}{2}}^+$, respectively. While the predictions for the masses of the $(L_\rho,L_\lambda)=(2,0)$ and $(1,1)$ D-wave $\Lambda_c$ and $\Xi_c$ states can be confronted to the experimental data in the future.
hep-ph/9803354
null
C. Hamzaoui and M. Pospelov
Up-Down Unification just above the supersymmetric threshold
12 pages, latex, two figures
Eur.Phys.J.C8:151-156,1999
10.1007/s100529901053
UQAM-PHE-98/01
hep-ph
null
Large corrections to the quark mass matrices at the supersymmetric threshold allow the theory to have identical Yukawa matrices in the superpotential. We demonstrate that Up-Down unification can take place in a moderate quark-squark alignment scenario with an average squark mass of the order 1 TeV and with $\tan\beta>15$
[ { "created": "Sat, 14 Mar 1998 23:28:16 GMT", "version": "v1" } ]
2011-02-01
[ [ "Hamzaoui", "C.", "" ], [ "Pospelov", "M.", "" ] ]
Large corrections to the quark mass matrices at the supersymmetric threshold allow the theory to have identical Yukawa matrices in the superpotential. We demonstrate that Up-Down unification can take place in a moderate quark-squark alignment scenario with an average squark mass of the order 1 TeV and with $\tan\beta>15$
2203.16356
Edward Shuryak
Edward Shuryak, Ismail Zahed
Instanton effects in Euclidean vacuum, real time production and in the light front wave functions
Lectures given at at 2021 Zakopane school, to appear in Acta Physica Polonica
null
null
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
Nontrivial topological structures of non-Abelian gauge fields were discovered in the 1970's. Instanton solutions, describing vacuum tunneling through topological barriers, have fermionic zero modes which are at the origin of $^\prime$t Hooft effective Lagrangian. In the 1980's instanton ensembles have been used to explain chiral symmetry breaking. In the 1990's a large set of numerical simulations were performed deriving Euclidean correlation functions. The special role of scalar diquarks in nucleons, and color superconductivity in dense quark matter have been elucidated. In these lectures, we discuss further developments of physics related to gauge topology. We show that the instanton-antiinstanton "streamline" configurations describe "sphaleron transitions" in high energy collisions, which result in production of hadronic clusters with nontrivial topological/chiral charges. (They are not yet observed, but discussions of dedicated experiments at LHC and RHIC are ongoing.) Another new direction is instanton effects in hadronic spectroscopy, both in the rest frame and on the light front. We will discuss their role in central and spin-dependent potentials, formfactors and antiquark nuclear "sea". Finally, we summarize the advances in the semiclassical theory of deconfinement, and chiral phase transitions at finite temperature, in QCD and in some of its "deformed" versions.
[ { "created": "Wed, 30 Mar 2022 14:32:39 GMT", "version": "v1" } ]
2022-03-31
[ [ "Shuryak", "Edward", "" ], [ "Zahed", "Ismail", "" ] ]
Nontrivial topological structures of non-Abelian gauge fields were discovered in the 1970's. Instanton solutions, describing vacuum tunneling through topological barriers, have fermionic zero modes which are at the origin of $^\prime$t Hooft effective Lagrangian. In the 1980's instanton ensembles have been used to explain chiral symmetry breaking. In the 1990's a large set of numerical simulations were performed deriving Euclidean correlation functions. The special role of scalar diquarks in nucleons, and color superconductivity in dense quark matter have been elucidated. In these lectures, we discuss further developments of physics related to gauge topology. We show that the instanton-antiinstanton "streamline" configurations describe "sphaleron transitions" in high energy collisions, which result in production of hadronic clusters with nontrivial topological/chiral charges. (They are not yet observed, but discussions of dedicated experiments at LHC and RHIC are ongoing.) Another new direction is instanton effects in hadronic spectroscopy, both in the rest frame and on the light front. We will discuss their role in central and spin-dependent potentials, formfactors and antiquark nuclear "sea". Finally, we summarize the advances in the semiclassical theory of deconfinement, and chiral phase transitions at finite temperature, in QCD and in some of its "deformed" versions.
hep-ph/0005214
Masahiro Yamaguchi
Fumihiro Takayama and Masahiro Yamaguchi
Gravitino Dark Matter without R-parity
11 pages, 1 figure
Phys.Lett.B485:388-392,2000
10.1016/S0370-2693(00)00726-7
TU-590
hep-ph
null
Cosmological issues are examined when gravitino is the lightest superparticle (LSP) and R-parity is broken. Decays of the next lightest superparticles occur rapidly via R-parity violating interaction, and thus they do not upset the big-bang nucleosynthesis, unlike the R-parity conserving case. The gravitino LSP becomes unstable, but its lifetime is typically much longer than the age of the Universe. It turns out that observations of diffuse photon background coming from radiative decays of the gravitino do not severely constrain the gravitino abundance, and thus the gravitino weighing less than around 1 GeV can be dark matter of the Universe when bilinear R-parity violation generates a neutrino mass which accounts for the atmospheric neutrino anomaly.
[ { "created": "Mon, 22 May 2000 07:59:25 GMT", "version": "v1" } ]
2011-05-05
[ [ "Takayama", "Fumihiro", "" ], [ "Yamaguchi", "Masahiro", "" ] ]
Cosmological issues are examined when gravitino is the lightest superparticle (LSP) and R-parity is broken. Decays of the next lightest superparticles occur rapidly via R-parity violating interaction, and thus they do not upset the big-bang nucleosynthesis, unlike the R-parity conserving case. The gravitino LSP becomes unstable, but its lifetime is typically much longer than the age of the Universe. It turns out that observations of diffuse photon background coming from radiative decays of the gravitino do not severely constrain the gravitino abundance, and thus the gravitino weighing less than around 1 GeV can be dark matter of the Universe when bilinear R-parity violation generates a neutrino mass which accounts for the atmospheric neutrino anomaly.
1910.01533
Aniello Quaranta
Antonio Capolupo, Gaetano Lambiase, Aniello Quaranta, Salvatore Marco Giampaolo
Probing axion mediated fermion--fermion interaction by means of entanglement
7 pages, 1 figure
Phys. Lett. B, Vol. 804, 135407 (2020)
10.1016/j.physletb.2020.135407
null
hep-ph hep-th quant-ph
http://creativecommons.org/licenses/by/4.0/
We propose a new approach in the investigation and detection of axion and axion-like particles based on the study of the entanglement for two interacting fermions. We study a system made of two identical fermions with spin-1/2, and we show that fermion-fermion interaction mediated by axions leads to a non-zero entanglement between the fermions. An entanglement measurement can reveal the interaction, providing an indirect evidence of the existence of axions. We discuss how the other interactions affect the entanglement, and how to isolate the axion contribution. Particular care is devoted to the analysis of the magnetic dipole-dipole interaction, which turns out to be, apart from axions, the most relevant contribution to the entanglement, and we show that it can be suppressed by setting opportunely the duration of the observation. We also introduce a two-body correlation function, which could be directly observed in an experiment, and plays the role of an entanglement witness.
[ { "created": "Thu, 3 Oct 2019 14:48:49 GMT", "version": "v1" }, { "created": "Mon, 14 Oct 2019 17:04:27 GMT", "version": "v2" }, { "created": "Sat, 30 Nov 2019 16:11:48 GMT", "version": "v3" }, { "created": "Wed, 8 Apr 2020 18:01:26 GMT", "version": "v4" } ]
2021-01-19
[ [ "Capolupo", "Antonio", "" ], [ "Lambiase", "Gaetano", "" ], [ "Quaranta", "Aniello", "" ], [ "Giampaolo", "Salvatore Marco", "" ] ]
We propose a new approach in the investigation and detection of axion and axion-like particles based on the study of the entanglement for two interacting fermions. We study a system made of two identical fermions with spin-1/2, and we show that fermion-fermion interaction mediated by axions leads to a non-zero entanglement between the fermions. An entanglement measurement can reveal the interaction, providing an indirect evidence of the existence of axions. We discuss how the other interactions affect the entanglement, and how to isolate the axion contribution. Particular care is devoted to the analysis of the magnetic dipole-dipole interaction, which turns out to be, apart from axions, the most relevant contribution to the entanglement, and we show that it can be suppressed by setting opportunely the duration of the observation. We also introduce a two-body correlation function, which could be directly observed in an experiment, and plays the role of an entanglement witness.
1303.0003
Mattias Blennow
Mattias Blennow, Pilar Coloma, Andrea Donini, Enrique Fernandez-Martinez
Gain fractions of future neutrino oscillation facilities over T2K and NOvA
JHEP style, 23 pages, 9 pdf figures
null
10.1007/JHEP07(2013)159
IFIC/13-07, IFT-UAM/CSIC-13-019, FTUAM-13-130
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We evaluate the probability of future neutrino oscillation facilities to discover leptonic CP violation and/or measure the neutrino mass hierarchy. We study how this probability is affected by positive or negative hints for these observables to be found at T2K and NOvA. We consider the following facilities: LBNE; T2HK; and the 10 GeV Neutrino Factory (NF10), and show how their discovery probabilities change with the running time of T2K and NOvA conditioned to their results. We find that, if after 15 years T2K and NOvA have not observed a 90% CL hint of CP violation, then LBNE and T2HK have less than a 10% chance of achieving a 5sigma discovery, whereas NF10 still has a ca 40% chance to do so. Conversely, if T2K and NOvA have an early 90% CL hint in 5 years from now, T2HK has a rather large chance to achieve a 5sigma CP violation discovery (75% or 55%, depending on whether the mass hierarchy is known or not). This is to be compared with the 90% (30%) probability that NF10 (LBNE) would have to observe the same signal at 5sigma. A hierarchy measurement at 5sigma is achievable at both LBNE and NF10 with more than 90% probability, irrespectively of the outcome of T2K and NOvA. We also find that if LBNE or a similar very long baseline super-beam is the only next generation facility to be built, then it is very useful to continue running T2K and NOvA (or at least T2K) beyond their original schedule in order to increase the CP violation discovery chances, given their complementarity.
[ { "created": "Thu, 28 Feb 2013 21:00:01 GMT", "version": "v1" } ]
2015-06-15
[ [ "Blennow", "Mattias", "" ], [ "Coloma", "Pilar", "" ], [ "Donini", "Andrea", "" ], [ "Fernandez-Martinez", "Enrique", "" ] ]
We evaluate the probability of future neutrino oscillation facilities to discover leptonic CP violation and/or measure the neutrino mass hierarchy. We study how this probability is affected by positive or negative hints for these observables to be found at T2K and NOvA. We consider the following facilities: LBNE; T2HK; and the 10 GeV Neutrino Factory (NF10), and show how their discovery probabilities change with the running time of T2K and NOvA conditioned to their results. We find that, if after 15 years T2K and NOvA have not observed a 90% CL hint of CP violation, then LBNE and T2HK have less than a 10% chance of achieving a 5sigma discovery, whereas NF10 still has a ca 40% chance to do so. Conversely, if T2K and NOvA have an early 90% CL hint in 5 years from now, T2HK has a rather large chance to achieve a 5sigma CP violation discovery (75% or 55%, depending on whether the mass hierarchy is known or not). This is to be compared with the 90% (30%) probability that NF10 (LBNE) would have to observe the same signal at 5sigma. A hierarchy measurement at 5sigma is achievable at both LBNE and NF10 with more than 90% probability, irrespectively of the outcome of T2K and NOvA. We also find that if LBNE or a similar very long baseline super-beam is the only next generation facility to be built, then it is very useful to continue running T2K and NOvA (or at least T2K) beyond their original schedule in order to increase the CP violation discovery chances, given their complementarity.
2402.14199
Gramos Qerimi
Simone Biondini, Nora Brambilla, Gramos Qerimi, Antonio Vairo
Center-of-mass recoil effects on the annihilation and formation of dark matter bound pairs
7 pages, 1 figure; Talk given at EPS-HEP2023 and TAUP2023
Proceedings of Science (PoS) 2024
10.22323/1.449.0112
TUM-EFT 184/23
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
For a quantitative investigation on the time evolution of heavy thermal dark matter at and after thermal freeze-out, near-threshold processes need to be taken into account which have a large impact on the observed dark matter relic abundance. In this conference paper, we study the recoil effect of heavy dark matter pairs in a thermal bath and compute the annihilation cross section and the decay width as well as the bound-state formation cross section of dark matter fermion-antifermion pairs in the laboratory frame within the framework of potential non-relativistic effective field theories at finite temperature. For the considered hierarchy of energy scales, we highlight the effect of the recoil corrections to the thermal rates.
[ { "created": "Thu, 22 Feb 2024 00:57:21 GMT", "version": "v1" } ]
2024-02-23
[ [ "Biondini", "Simone", "" ], [ "Brambilla", "Nora", "" ], [ "Qerimi", "Gramos", "" ], [ "Vairo", "Antonio", "" ] ]
For a quantitative investigation on the time evolution of heavy thermal dark matter at and after thermal freeze-out, near-threshold processes need to be taken into account which have a large impact on the observed dark matter relic abundance. In this conference paper, we study the recoil effect of heavy dark matter pairs in a thermal bath and compute the annihilation cross section and the decay width as well as the bound-state formation cross section of dark matter fermion-antifermion pairs in the laboratory frame within the framework of potential non-relativistic effective field theories at finite temperature. For the considered hierarchy of energy scales, we highlight the effect of the recoil corrections to the thermal rates.
2211.11670
Manjunath Omana Kuttan
Manjunath Omana Kuttan, Jan Steinheimer, Kai Zhou, Horst Stoecker
QCD Equation of State of Dense Nuclear Matter from a Bayesian Analysis of Heavy-Ion Collision Data
Replaced with the published version
Phys. Rev. Lett. 131, 202303 (2023)
10.1103/PhysRevLett.131.202303
null
hep-ph hep-ex nucl-ex nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Bayesian methods are used to constrain the density dependence of the QCD Equation of State (EoS) for dense nuclear matter using the data of mean transverse kinetic energy and elliptic flow of protons from heavy ion collisions (HIC), in the beam energy range $\sqrt{s_{\mathrm{NN}}}=2-10 GeV$. The analysis yields tight constraints on the density dependent EoS up to 4 times the nuclear saturation density. The extracted EoS yields good agreement with other observables measured in HIC experiments and constraints from astrophysical observations both of which were not used in the inference. The sensitivity of inference to the choice of observables is also discussed.
[ { "created": "Mon, 21 Nov 2022 17:39:26 GMT", "version": "v1" }, { "created": "Tue, 22 Nov 2022 12:10:18 GMT", "version": "v2" }, { "created": "Fri, 17 Nov 2023 13:58:32 GMT", "version": "v3" } ]
2023-11-20
[ [ "Kuttan", "Manjunath Omana", "" ], [ "Steinheimer", "Jan", "" ], [ "Zhou", "Kai", "" ], [ "Stoecker", "Horst", "" ] ]
Bayesian methods are used to constrain the density dependence of the QCD Equation of State (EoS) for dense nuclear matter using the data of mean transverse kinetic energy and elliptic flow of protons from heavy ion collisions (HIC), in the beam energy range $\sqrt{s_{\mathrm{NN}}}=2-10 GeV$. The analysis yields tight constraints on the density dependent EoS up to 4 times the nuclear saturation density. The extracted EoS yields good agreement with other observables measured in HIC experiments and constraints from astrophysical observations both of which were not used in the inference. The sensitivity of inference to the choice of observables is also discussed.
0801.2680
Thomas Gehrmann
A. Gehrmann-De Ridder, T. Gehrmann, E.W.N. Glover, G. Heinrich
Event shapes in $e^+e^-$ annhilation at NNLO
6 pages, contribution to the Proceedings of RADCOR07, Florence
PoS RADCOR2007:048,2007
null
ZU-TH 02/08, IPPP/08/02
hep-ph
null
We report first results on the calculation of NNLO corrections to event shape distributions in electron-positron annhilation. The corrections are sizeable for all variables, however their magnitude is substantially different for different observables. We observe that inclusion of the NNLO corrections yields a considerably better agreement between theory and experimental data both in shape and normalisation of the event shape distributions.
[ { "created": "Thu, 17 Jan 2008 14:05:14 GMT", "version": "v1" } ]
2008-12-30
[ [ "Ridder", "A. Gehrmann-De", "" ], [ "Gehrmann", "T.", "" ], [ "Glover", "E. W. N.", "" ], [ "Heinrich", "G.", "" ] ]
We report first results on the calculation of NNLO corrections to event shape distributions in electron-positron annhilation. The corrections are sizeable for all variables, however their magnitude is substantially different for different observables. We observe that inclusion of the NNLO corrections yields a considerably better agreement between theory and experimental data both in shape and normalisation of the event shape distributions.
1001.0221
Brian Yencho
Vernon Barger, Wai-Yee Keung, Brian Yencho
Triple-Top Signal of New Physics at the LHC
12 pages, 5 figures, 3 tables
Phys.Lett.B687:70-74,2010
10.1016/j.physletb.2010.03.001
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present leading-order (LO) cross sections for the production of three top quarks ($tt\tb$,$t\tb\tb$) at the Large Hadron Collider (LHC). We find a total LO cross section for triple-top production in the Standard Model of $\sigma \approx 2 $ fb at $\sqrt{s}=14$ TeV and we give examples of two new physics models which have a significant enhancement to this channel. In the Minimal Supersymmetric Standard Model (MSSM), there are regions of parameter space where the decays of gluino pairs into final states including three tops has a cross section $\sigma \approx 41$ fb. In a leptophobic $Z'$ model featuring right-handed couplings of the $u$-quark to the top, we find $\sigma \approx 28$ fb. With efficient identification and reconstruction of the top quarks, the triple-top signal could potentially provide evidence for new physics at the LHC.
[ { "created": "Mon, 4 Jan 2010 20:14:15 GMT", "version": "v1" }, { "created": "Wed, 2 Jun 2010 16:21:16 GMT", "version": "v2" }, { "created": "Wed, 1 Dec 2010 16:38:22 GMT", "version": "v3" } ]
2010-12-02
[ [ "Barger", "Vernon", "" ], [ "Keung", "Wai-Yee", "" ], [ "Yencho", "Brian", "" ] ]
We present leading-order (LO) cross sections for the production of three top quarks ($tt\tb$,$t\tb\tb$) at the Large Hadron Collider (LHC). We find a total LO cross section for triple-top production in the Standard Model of $\sigma \approx 2 $ fb at $\sqrt{s}=14$ TeV and we give examples of two new physics models which have a significant enhancement to this channel. In the Minimal Supersymmetric Standard Model (MSSM), there are regions of parameter space where the decays of gluino pairs into final states including three tops has a cross section $\sigma \approx 41$ fb. In a leptophobic $Z'$ model featuring right-handed couplings of the $u$-quark to the top, we find $\sigma \approx 28$ fb. With efficient identification and reconstruction of the top quarks, the triple-top signal could potentially provide evidence for new physics at the LHC.
hep-ph/9403254
null
S. Narison
Precise Determination of {$f_{P_{s}}/f_P$}} {\bf and Measurement of the ``Perturbative'' Pole Mass from {$f_P$}}
{{\bf \bf 9 pages, CERN-TH 7094/93 (published in Phys. Lett. B322 (1994) 247 )
Phys.Lett.B322:247-252,1994
10.1016/0370-2693(94)91115-0
null
hep-ph
null
We present a compact analytic two-loop expression of the $SU(3)_f$ breaking effects on the ratio of the pseudoscalar decay constants $R_P \equiv f_{P_S}/f_P$ ($P \equiv D,B $), from which, we extract the precise values : $R_D = 1.15 \pm .04$, $R_B = 1.16 \pm .05 $, where the errors are mainly due to the uncalculated $\alpha_s^2$-corrections. We also scan carefully the $M_c$ (resp. $M_b$) mass dependence of $f_D$ (resp. $f_B$) in view of precise measurements of the ``perturbative'' c and b pole quark masses from the future data of the decay constants $f_P$.
[ { "created": "Wed, 9 Mar 1994 18:03:11 GMT", "version": "v1" } ]
2011-01-27
[ [ "Narison", "S.", "" ] ]
We present a compact analytic two-loop expression of the $SU(3)_f$ breaking effects on the ratio of the pseudoscalar decay constants $R_P \equiv f_{P_S}/f_P$ ($P \equiv D,B $), from which, we extract the precise values : $R_D = 1.15 \pm .04$, $R_B = 1.16 \pm .05 $, where the errors are mainly due to the uncalculated $\alpha_s^2$-corrections. We also scan carefully the $M_c$ (resp. $M_b$) mass dependence of $f_D$ (resp. $f_B$) in view of precise measurements of the ``perturbative'' c and b pole quark masses from the future data of the decay constants $f_P$.
1703.06892
Samuel Witte
Samuel J. Witte and Graciela B. Gelmini
Updated Constraints on the Dark Matter Interpretation of CDMS-II-Si Data
v2: Published version. Figure 7 added and text modified, conclusions unchanged. v1: 18 pages, 6 figures
null
10.1088/1475-7516/2017/05/026
null
hep-ph astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present an updated halo-dependent and halo-independent analysis of viable light WIMP dark matter candidates which could account for the excess observed in CDMS-II-Si. We include recent constraints from LUX, PandaX-II, and PICO-60, as well as projected sensitivities for XENON1T, SuperCDMS SNOLAB, LZ, DARWIN, DarkSide-20k, and PICO-250, on candidates with spin-independent isospin conserving and isospin-violating interactions, and either elastic or exothermic scattering. We show that there exist dark matter candidates which can explain the CDMS-II-Si data and remain very marginally consistent with the null results of all current experiments, however such models are highly tuned, making a dark matter interpretation of CDMS-II-Si very unlikely. We find that these models can only be ruled out in the future by an experiment comparable to LZ or PICO-250.
[ { "created": "Mon, 20 Mar 2017 18:00:14 GMT", "version": "v1" }, { "created": "Wed, 3 May 2017 18:00:00 GMT", "version": "v2" } ]
2017-05-24
[ [ "Witte", "Samuel J.", "" ], [ "Gelmini", "Graciela B.", "" ] ]
We present an updated halo-dependent and halo-independent analysis of viable light WIMP dark matter candidates which could account for the excess observed in CDMS-II-Si. We include recent constraints from LUX, PandaX-II, and PICO-60, as well as projected sensitivities for XENON1T, SuperCDMS SNOLAB, LZ, DARWIN, DarkSide-20k, and PICO-250, on candidates with spin-independent isospin conserving and isospin-violating interactions, and either elastic or exothermic scattering. We show that there exist dark matter candidates which can explain the CDMS-II-Si data and remain very marginally consistent with the null results of all current experiments, however such models are highly tuned, making a dark matter interpretation of CDMS-II-Si very unlikely. We find that these models can only be ruled out in the future by an experiment comparable to LZ or PICO-250.
hep-ph/9211325
null
J. Ellis, D.V. Nanopoulos and K. Olive
Flipped Heavy Neutrinos from the Solar Neutrino Problem to Baryogenesis
12 pages, 1 figure not included, CERN-TH.6712/92
Phys.Lett.B300:121-127,1993
10.1016/0370-2693(93)90758-A
null
hep-ph astro-ph
null
We discuss baryogenesis using the flipped $SU(5)$ model for lepton mass matrices. We show that the generalized see-saw mechanism in this model can not only provide MSW neutrino mixing suitable for solving the solar neutrino problem, and supply a hot dark matter candidate ($\nu_\tau$) with mass $0(10)eV$ as indicated by recent COBE results, but can also naturally account for the baryon asymmetry of the universe. Heavy singlet neutrino decay generates a net lepton asymmetry which is subsequently reprocessed by nonperturbative electroweak interactions. We evaluate the baryon asymmetry so produced in light of the constraints that the COBE observations put on inflationary cosmologies, finding it comfortably consistent with observation.
[ { "created": "Fri, 27 Nov 1992 16:38:40 GMT", "version": "v1" } ]
2009-09-11
[ [ "Ellis", "J.", "" ], [ "Nanopoulos", "D. V.", "" ], [ "Olive", "K.", "" ] ]
We discuss baryogenesis using the flipped $SU(5)$ model for lepton mass matrices. We show that the generalized see-saw mechanism in this model can not only provide MSW neutrino mixing suitable for solving the solar neutrino problem, and supply a hot dark matter candidate ($\nu_\tau$) with mass $0(10)eV$ as indicated by recent COBE results, but can also naturally account for the baryon asymmetry of the universe. Heavy singlet neutrino decay generates a net lepton asymmetry which is subsequently reprocessed by nonperturbative electroweak interactions. We evaluate the baryon asymmetry so produced in light of the constraints that the COBE observations put on inflationary cosmologies, finding it comfortably consistent with observation.
0709.2913
C. A. de S. Pires
D. Cogollo, H. Diniz, C. A. de S. Pires, P. S. Rodrigues da Silva
Fermion family number and the Z-Z$^{\prime}$ mixing in the 3-3-1 model with right-handed neutrinos
Minor modification in the conclusions, some refs added, to appear at MPLA
Mod.Phys.Lett.A23:3405-3410,2009
10.1142/S0217732308027382
null
hep-ph
null
Theoretical consistency of the 3-3-1 model with right-handed neutrinos demands that the number of family of fermions be exactly equal to three. In this brief report we show that such theoretical requirement results in a clean and severe bound on the Z-Z$^{\prime}$ mixing angle: $-3,979\times 10^{-3}<\phi<1,309\times 10^{-4} {with 90% CL}$.
[ { "created": "Tue, 18 Sep 2007 20:06:37 GMT", "version": "v1" }, { "created": "Tue, 3 Jun 2008 13:31:58 GMT", "version": "v2" } ]
2009-02-12
[ [ "Cogollo", "D.", "" ], [ "Diniz", "H.", "" ], [ "Pires", "C. A. de S.", "" ], [ "da Silva", "P. S. Rodrigues", "" ] ]
Theoretical consistency of the 3-3-1 model with right-handed neutrinos demands that the number of family of fermions be exactly equal to three. In this brief report we show that such theoretical requirement results in a clean and severe bound on the Z-Z$^{\prime}$ mixing angle: $-3,979\times 10^{-3}<\phi<1,309\times 10^{-4} {with 90% CL}$.
2202.11186
Manfred Kraus
Giuseppe Bevilacqua, Huan-Yu Bi, Heribertus Bayu Hartanto, Manfred Kraus, Michele Lupattelli, Malgorzata Worek
$t\bar{t}b\bar{b}$ at the LHC: On the size of off-shell effects and prompt $b$-jet identification
35 pages, 8 figures, 1 table, version to appear in PRD
Phys. Rev. D 107, 014028 (2023)
10.1103/PhysRevD.107.014028
TTK-22-06, P3H-22-012, CAVENDISH-HEP-22/02
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate full off-shell effects in $t\bar{t}b\bar{b}$ production in the dilepton channel at the LHC with the center-of-mass energy $\sqrt{s} = 13$ TeV. Specifically, we compute NLO QCD corrections to the $pp \to e^+ \nu_e \mu^- \bar{\nu}_\mu b \bar{b} b \bar{b} + X$ process and provide a prescription for $b$-jet identification to distinguish prompt $b$ jets from $b$ jets originating from the decay of the top quarks. As an important irreducible background to $pp \to t\bar{t}H (H\to b\bar{b})$, $t\bar{t}$ production in association with two prompt $b$ jets is a primary source of uncertainty in the measurement of $t\bar{t}H (H\to b\bar{b})$. In quantifying full off-shell effects, we perform comparisons between the state-of-the-art full off-shell computation and the calculation in the narrow width approximation. The former includes all double-, single- and non-resonant Feynman diagrams, interferences as well as finite-width effects of the top quarks and $W$ gauge bosons. The latter restricts the unstable top quarks and $W$ gauge bosons to on-shell states and includes for the first time NLO QCD corrections to both production and decays. We observe that full off-shell effects are subdominant compared to the scale uncertainties for the integrated fiducial cross section and for the majority of differential observables in the phase-space regions that we investigated. However, for a number of observables related to beyond the Standard Model searches, full off-shell effects are significant. Furthermore, with our $b$-jet labelling prescription, the prompt $b$ jets and the $b$ jets from top-quark decays can be successfully disentangled.
[ { "created": "Tue, 22 Feb 2022 21:42:32 GMT", "version": "v1" }, { "created": "Sun, 18 Sep 2022 15:12:20 GMT", "version": "v2" }, { "created": "Fri, 30 Dec 2022 15:22:14 GMT", "version": "v3" } ]
2023-01-31
[ [ "Bevilacqua", "Giuseppe", "" ], [ "Bi", "Huan-Yu", "" ], [ "Hartanto", "Heribertus Bayu", "" ], [ "Kraus", "Manfred", "" ], [ "Lupattelli", "Michele", "" ], [ "Worek", "Malgorzata", "" ] ]
We investigate full off-shell effects in $t\bar{t}b\bar{b}$ production in the dilepton channel at the LHC with the center-of-mass energy $\sqrt{s} = 13$ TeV. Specifically, we compute NLO QCD corrections to the $pp \to e^+ \nu_e \mu^- \bar{\nu}_\mu b \bar{b} b \bar{b} + X$ process and provide a prescription for $b$-jet identification to distinguish prompt $b$ jets from $b$ jets originating from the decay of the top quarks. As an important irreducible background to $pp \to t\bar{t}H (H\to b\bar{b})$, $t\bar{t}$ production in association with two prompt $b$ jets is a primary source of uncertainty in the measurement of $t\bar{t}H (H\to b\bar{b})$. In quantifying full off-shell effects, we perform comparisons between the state-of-the-art full off-shell computation and the calculation in the narrow width approximation. The former includes all double-, single- and non-resonant Feynman diagrams, interferences as well as finite-width effects of the top quarks and $W$ gauge bosons. The latter restricts the unstable top quarks and $W$ gauge bosons to on-shell states and includes for the first time NLO QCD corrections to both production and decays. We observe that full off-shell effects are subdominant compared to the scale uncertainties for the integrated fiducial cross section and for the majority of differential observables in the phase-space regions that we investigated. However, for a number of observables related to beyond the Standard Model searches, full off-shell effects are significant. Furthermore, with our $b$-jet labelling prescription, the prompt $b$ jets and the $b$ jets from top-quark decays can be successfully disentangled.
hep-ph/0003186
Pran Nath
Achille Corsetti and Pran Nath
Gaugino Mass Nonuniversality and Dark Matter in SUGRA, Strings and D Brane Models
Revised version, 23 pages, Latex, and 7 figures
Phys.Rev.D64:125010,2001
10.1103/PhysRevD.64.125010
null
hep-ph
null
The effects of nonuniversality of gaugino masses on dark matter are examined within supersymmetric grand unification, and in string and D brane models with R parity invariance. In SU(5) unified models nonuniversality in the gaugino sector can be generated via the gauge kinetic energy function which may depend on the 24, 75 and 200 dimensional Higgs representations. We also consider string models which allow for nonuniversality of gaugino masses and D brane models where nonuniversality arises from embeddings of the Standard Model gauge group on five branes and nine branes. It is found that with gaugino mass nonuniversality the range of the LSP mass can be extended much beyond the range allowed in the universal SUGRA case, up to about 600 GeV even without coannihilation effects in some regions of the parameter space. The effects of coannihilation are not considered and inclusion of these effects may further increase the allowed neutralino mass range. Similarly with the inclusion of gaugino mass nonuniversality, the neutralino-proton ($\chi -p$) cross-section can increase by as much as a factor of 10 in some of regions of the parameter space. An analysis of the uncertainties in the quark density content of the nucleon is given and their effects on $\chi -p$ cross-section are discussed. The predictions of our analysis including nonuniversality is compared with the current limits from dark matter detectors and implications for future dark matter searches are discussed.
[ { "created": "Fri, 17 Mar 2000 23:07:09 GMT", "version": "v1" }, { "created": "Fri, 27 Jul 2001 11:36:55 GMT", "version": "v2" } ]
2008-11-26
[ [ "Corsetti", "Achille", "" ], [ "Nath", "Pran", "" ] ]
The effects of nonuniversality of gaugino masses on dark matter are examined within supersymmetric grand unification, and in string and D brane models with R parity invariance. In SU(5) unified models nonuniversality in the gaugino sector can be generated via the gauge kinetic energy function which may depend on the 24, 75 and 200 dimensional Higgs representations. We also consider string models which allow for nonuniversality of gaugino masses and D brane models where nonuniversality arises from embeddings of the Standard Model gauge group on five branes and nine branes. It is found that with gaugino mass nonuniversality the range of the LSP mass can be extended much beyond the range allowed in the universal SUGRA case, up to about 600 GeV even without coannihilation effects in some regions of the parameter space. The effects of coannihilation are not considered and inclusion of these effects may further increase the allowed neutralino mass range. Similarly with the inclusion of gaugino mass nonuniversality, the neutralino-proton ($\chi -p$) cross-section can increase by as much as a factor of 10 in some of regions of the parameter space. An analysis of the uncertainties in the quark density content of the nucleon is given and their effects on $\chi -p$ cross-section are discussed. The predictions of our analysis including nonuniversality is compared with the current limits from dark matter detectors and implications for future dark matter searches are discussed.
hep-ph/0010280
Christopher Gordon
Arjun Berera (Edinburgh), Christopher Gordon (Portsmouth)
Inflationary Initial Conditions Consistent with Causality
9 pages, 3 figures. Minor changes, matches version to appear in Physical Review D
Phys.Rev. D63 (2001) 063505
10.1103/PhysRevD.63.063505
null
hep-ph astro-ph gr-qc hep-th
null
The initial condition problem of inflation is examined from the perspective of both spacetime embedding and scalar field dynamics. The spacetime embedding problem is solved for arbitrary initial spatial curvature Omega, which generalizes previous works that primarily treat the flat case Omega=1. Scalar field dynamics that is consistent with the embedding constraints are examined, with the additional treatment of damping effects. The effects of inhomogeneities on the embedding problem also are considered. A category of initial conditions are identified that are not acausal and can develop into an inflationary regime.
[ { "created": "Tue, 24 Oct 2000 21:36:17 GMT", "version": "v1" }, { "created": "Wed, 15 Nov 2000 11:56:41 GMT", "version": "v2" }, { "created": "Tue, 6 Feb 2001 14:55:58 GMT", "version": "v3" } ]
2009-10-31
[ [ "Berera", "Arjun", "", "Edinburgh" ], [ "Gordon", "Christopher", "", "Portsmouth" ] ]
The initial condition problem of inflation is examined from the perspective of both spacetime embedding and scalar field dynamics. The spacetime embedding problem is solved for arbitrary initial spatial curvature Omega, which generalizes previous works that primarily treat the flat case Omega=1. Scalar field dynamics that is consistent with the embedding constraints are examined, with the additional treatment of damping effects. The effects of inhomogeneities on the embedding problem also are considered. A category of initial conditions are identified that are not acausal and can develop into an inflationary regime.
1805.00013
Johann Brehmer Mr
Johann Brehmer, Kyle Cranmer, Gilles Louppe, and Juan Pavez
Constraining Effective Field Theories with Machine Learning
See also the companion publication "A Guide to Constraining Effective Field Theories with Machine Learning" at arXiv:1805.00020, an in-depth analysis of machine learning techniques for LHC measurements. The code for these studies is available at https://github.com/johannbrehmer/higgs_inference . v2: New schematic figure explaining the new algorithms, added references. v3, v4: Added references
Phys. Rev. Lett. 121, 111801 (2018)
10.1103/PhysRevLett.121.111801
null
hep-ph physics.data-an stat.ML
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present powerful new analysis techniques to constrain effective field theories at the LHC. By leveraging the structure of particle physics processes, we extract extra information from Monte-Carlo simulations, which can be used to train neural network models that estimate the likelihood ratio. These methods scale well to processes with many observables and theory parameters, do not require any approximations of the parton shower or detector response, and can be evaluated in microseconds. We show that they allow us to put significantly stronger bounds on dimension-six operators than existing methods, demonstrating their potential to improve the precision of the LHC legacy constraints.
[ { "created": "Mon, 30 Apr 2018 18:00:00 GMT", "version": "v1" }, { "created": "Sat, 12 May 2018 18:48:30 GMT", "version": "v2" }, { "created": "Fri, 1 Jun 2018 16:50:04 GMT", "version": "v3" }, { "created": "Thu, 26 Jul 2018 19:00:29 GMT", "version": "v4" } ]
2018-09-19
[ [ "Brehmer", "Johann", "" ], [ "Cranmer", "Kyle", "" ], [ "Louppe", "Gilles", "" ], [ "Pavez", "Juan", "" ] ]
We present powerful new analysis techniques to constrain effective field theories at the LHC. By leveraging the structure of particle physics processes, we extract extra information from Monte-Carlo simulations, which can be used to train neural network models that estimate the likelihood ratio. These methods scale well to processes with many observables and theory parameters, do not require any approximations of the parton shower or detector response, and can be evaluated in microseconds. We show that they allow us to put significantly stronger bounds on dimension-six operators than existing methods, demonstrating their potential to improve the precision of the LHC legacy constraints.
0811.4119
Michal Czakon
M. Czakon and A. Mitov
Inclusive Heavy Flavor Hadroproduction in NLO QCD: the Exact Analytic Result
26 pages, 6 figures, file containing the results in Mathematica format attached
Nucl.Phys.B824:111-135,2010
10.1016/j.nuclphysb.2009.08.020
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present the first exact analytic result for all partonic channels contributing to the total cross section for the production of a pair of heavy flavors in hadronic collisions in NLO QCD. Our calculation is an essential step in the derivation of the top quark pair production cross section at NNLO in QCD, which is a cornerstone of the precision LHC program. Our results uncover the analytical structures behind observables with heavy flavors at higher orders. They also reveal surprising and non-trivial implications for kinematics close to partonic threshold.
[ { "created": "Tue, 25 Nov 2008 16:22:17 GMT", "version": "v1" } ]
2009-10-06
[ [ "Czakon", "M.", "" ], [ "Mitov", "A.", "" ] ]
We present the first exact analytic result for all partonic channels contributing to the total cross section for the production of a pair of heavy flavors in hadronic collisions in NLO QCD. Our calculation is an essential step in the derivation of the top quark pair production cross section at NNLO in QCD, which is a cornerstone of the precision LHC program. Our results uncover the analytical structures behind observables with heavy flavors at higher orders. They also reveal surprising and non-trivial implications for kinematics close to partonic threshold.
2111.14701
Vo Van Vien
V. V. Vien
$\mathbf{B-L}$ model with $\mathbf{D_4\times Z_4\times Z_2}$ symmetry for fermion mass hierarchies and mixings
30 pages, 17 figures, 4 tables; the lepton sector is added
Chinese Phys. C 48 (2024) 063102
10.1088/1674-1137/ad2f23
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We construct a gauge $B-L$ model with $D_4\times Z_4\times Z_2$ symmetry that can explain the quark and lepton mass hierarchies and their mixings with the realistic CP phases via the type-I seesaw mechanism. Six quark mases, three quark mixing angles and CP phase in the quark sector can get the central values and Yukawa couplings in the quark sector are diluted a range of three orders of magnitude difference by the perturbation theory at the first order. For neutrino sector, the smallness of neutrino mass is achieved by the Type-I seesaw mechanism. Both inverted and normal neutrino mass hierarchies are in consistent with the experimental data. The prediction for the sum of neutrino masses for normal and inverted hierarchies, the effective neutrino masses and the Dirac CP phase are well consistent with all the recent limits.
[ { "created": "Mon, 29 Nov 2021 17:00:27 GMT", "version": "v1" }, { "created": "Wed, 9 Feb 2022 08:59:45 GMT", "version": "v2" }, { "created": "Sat, 17 Dec 2022 10:25:33 GMT", "version": "v3" }, { "created": "Wed, 1 May 2024 02:50:54 GMT", "version": "v4" } ]
2024-05-02
[ [ "Vien", "V. V.", "" ] ]
We construct a gauge $B-L$ model with $D_4\times Z_4\times Z_2$ symmetry that can explain the quark and lepton mass hierarchies and their mixings with the realistic CP phases via the type-I seesaw mechanism. Six quark mases, three quark mixing angles and CP phase in the quark sector can get the central values and Yukawa couplings in the quark sector are diluted a range of three orders of magnitude difference by the perturbation theory at the first order. For neutrino sector, the smallness of neutrino mass is achieved by the Type-I seesaw mechanism. Both inverted and normal neutrino mass hierarchies are in consistent with the experimental data. The prediction for the sum of neutrino masses for normal and inverted hierarchies, the effective neutrino masses and the Dirac CP phase are well consistent with all the recent limits.
hep-ph/9907284
null
Giancarlo D'Ambrosio
Rare kaon decays
7 pages LaTeX, Talk given at La Thuile Conference, 28th February- 7th March '99. Erratum in References corrected
null
null
INFN-NA-IV 24/99
hep-ph
null
We review some recent theoretical results on rare kaon decays. Particular attention is devoted to establish the short distance (direct CP violating) contribution to K_L => \pi^0 e \bar{e}. This is achieved by a careful study of the long distance part. As byproduct, we discuss interesting chiral tests.
[ { "created": "Fri, 9 Jul 1999 10:43:51 GMT", "version": "v1" }, { "created": "Tue, 20 Jul 1999 16:52:55 GMT", "version": "v2" } ]
2007-05-23
[ [ "D'Ambrosio", "Giancarlo", "" ] ]
We review some recent theoretical results on rare kaon decays. Particular attention is devoted to establish the short distance (direct CP violating) contribution to K_L => \pi^0 e \bar{e}. This is achieved by a careful study of the long distance part. As byproduct, we discuss interesting chiral tests.
hep-ph/9904211
Smirnov Alexei
Gia Dvali and Alexei Yu. Smirnov
Probing Large Extra Dimensions with Neutrinos
LaTeX, 23 pages and 1 figure, slight revision of the manuscript, new discussion added, several formulas corrected
Nucl.Phys. B563 (1999) 63-81
10.1016/S0550-3213(99)00574-X
NYU-TH/99/3/03, IC/99/32
hep-ph
null
We study implications of theories with sub-millimeter extra dimensions and $M_f \sim (1 - 10) $ TeV scale quantum gravity for neutrino physics. In these theories, the left-handed neutrinos as well as other standard model (SM) particles, are localized on a brane embedded in the bulk of large extra space. Mixing of neutrinos with (SM) singlet fermions propagating in the bulk is naturally suppressed by the volume factor $M_f/M_P \sim 3\cdot 10^{-16} - 3\cdot 10^{-15}$, where $M_P$ is the Planck mass. Properties of the neutrino oscillations and the resonance conversion to the bulk fermions are considered. We show that the resonance conversion of the electron neutrinos to the light bulk fermions can solve the solar neutrino problem. The signature of the solution is the peculiar distortion of the solar neutrino spectrum. The solution implies that the radius of at least one extra dimension should be in the range 0.06 - 0.1 mm {\it irrespective} of total number of extra dimensions. The corresponding modification of the Newtonian law is within the range of sensitivity of proposed sub-millimeter experiments, thus providing a verifiable link between neutrino physics and the gravity measurements.
[ { "created": "Thu, 1 Apr 1999 20:46:25 GMT", "version": "v1" }, { "created": "Tue, 15 Jun 1999 18:45:38 GMT", "version": "v2" } ]
2009-10-31
[ [ "Dvali", "Gia", "" ], [ "Smirnov", "Alexei Yu.", "" ] ]
We study implications of theories with sub-millimeter extra dimensions and $M_f \sim (1 - 10) $ TeV scale quantum gravity for neutrino physics. In these theories, the left-handed neutrinos as well as other standard model (SM) particles, are localized on a brane embedded in the bulk of large extra space. Mixing of neutrinos with (SM) singlet fermions propagating in the bulk is naturally suppressed by the volume factor $M_f/M_P \sim 3\cdot 10^{-16} - 3\cdot 10^{-15}$, where $M_P$ is the Planck mass. Properties of the neutrino oscillations and the resonance conversion to the bulk fermions are considered. We show that the resonance conversion of the electron neutrinos to the light bulk fermions can solve the solar neutrino problem. The signature of the solution is the peculiar distortion of the solar neutrino spectrum. The solution implies that the radius of at least one extra dimension should be in the range 0.06 - 0.1 mm {\it irrespective} of total number of extra dimensions. The corresponding modification of the Newtonian law is within the range of sensitivity of proposed sub-millimeter experiments, thus providing a verifiable link between neutrino physics and the gravity measurements.
0909.4181
Carlos E. Yaguna
Carlos E. Yaguna
Gamma ray lines: what will they tell us about SUSY?
19 pages, 10 figures
Phys.Rev.D80:115002,2009
10.1103/PhysRevD.80.115002
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Neutralino dark matter can be indirectly detected by observing the gamma ray lines from the annihilation processes XX-->gg and XX-->gZ. In this paper we study the implications that the observation of these two lines could have for the determination of the supersymmetric parameter space. Within the minimal supergravity framework, we find that, independently of the dark matter distribution in the Galaxy, such observations by themselves would allow to differentiate between the coannihilation region, the funnel region, and the focus point region. As a result, several restrictions on the msugra parameters can be derived. Within a more general MSSM scenario, we show that the observation of gamma-ray lines might be used to discriminate between a bino-, a wino-, and a higgsino-like neutralino, with important consequences for cosmology and for models of supersymmetry breaking. The detection of the gamma ray lines, therefore, will not only provide an unmistakable signature of dark matter, it will also open a new road toward the determination of supersymmetric parameters.
[ { "created": "Wed, 23 Sep 2009 11:10:27 GMT", "version": "v1" } ]
2010-01-08
[ [ "Yaguna", "Carlos E.", "" ] ]
Neutralino dark matter can be indirectly detected by observing the gamma ray lines from the annihilation processes XX-->gg and XX-->gZ. In this paper we study the implications that the observation of these two lines could have for the determination of the supersymmetric parameter space. Within the minimal supergravity framework, we find that, independently of the dark matter distribution in the Galaxy, such observations by themselves would allow to differentiate between the coannihilation region, the funnel region, and the focus point region. As a result, several restrictions on the msugra parameters can be derived. Within a more general MSSM scenario, we show that the observation of gamma-ray lines might be used to discriminate between a bino-, a wino-, and a higgsino-like neutralino, with important consequences for cosmology and for models of supersymmetry breaking. The detection of the gamma ray lines, therefore, will not only provide an unmistakable signature of dark matter, it will also open a new road toward the determination of supersymmetric parameters.
1402.6668
Maria Angeles Hernandez-Ruiz
Maria A. Hernandez-Ruiz
The baryon axial current in large $N_c$ chiral perturbation theory
Ph.D. Thesis, IF-UASLP, December 2012, 109 pages, fully in Spanish
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this thesis we calculate the baryon axial current within the combined framework of the $1/N_c$ expansion and chiral perturbation theory, where $N_c$ is the number of colors. This calculation shall consider Feynman diagrams to order of one-loop, octet and decuplet intermediaries states. We obtain corrections due to one-loop and perturbative SU(3) symmetry breaking. The first corrections come from Feynman diagrams, then talk about a broken chiral symmetry in the implicit limit $m_q \rightarrow 0$, where $m_q$ is the quark mass and the second corrections are obtained by ignoring isospin breaking and in that case the SU(3) symmetry breaking a first-order perturbation is included, leading an explicit break symmetry. The matrix elements of the spatial components of the axial operator between the states of the spin flavor symmetry, give the typical values of the axial vector coupling. For the baryon octet, links axial vector are $g_A$, just as they are defined in experiments of baryon semileptonic decays, where $g_A \approx 1.27$ for neutron beta decay. In strong decays of the baryon axial vector couplings are $g$, which are extracted from the widths of the strong decays of baryon decuplet to octet of baryons and pions. The calculation of this work allows us to make various settings by minimum squares, i.e., adjusting our analytical expressions with data pilot can make the comparison between theory and experiment. We found the comparison of our theoretical results with the experiment are in total agreement.
[ { "created": "Wed, 26 Feb 2014 20:18:41 GMT", "version": "v1" }, { "created": "Tue, 17 Nov 2015 00:27:35 GMT", "version": "v2" } ]
2015-11-18
[ [ "Hernandez-Ruiz", "Maria A.", "" ] ]
In this thesis we calculate the baryon axial current within the combined framework of the $1/N_c$ expansion and chiral perturbation theory, where $N_c$ is the number of colors. This calculation shall consider Feynman diagrams to order of one-loop, octet and decuplet intermediaries states. We obtain corrections due to one-loop and perturbative SU(3) symmetry breaking. The first corrections come from Feynman diagrams, then talk about a broken chiral symmetry in the implicit limit $m_q \rightarrow 0$, where $m_q$ is the quark mass and the second corrections are obtained by ignoring isospin breaking and in that case the SU(3) symmetry breaking a first-order perturbation is included, leading an explicit break symmetry. The matrix elements of the spatial components of the axial operator between the states of the spin flavor symmetry, give the typical values of the axial vector coupling. For the baryon octet, links axial vector are $g_A$, just as they are defined in experiments of baryon semileptonic decays, where $g_A \approx 1.27$ for neutron beta decay. In strong decays of the baryon axial vector couplings are $g$, which are extracted from the widths of the strong decays of baryon decuplet to octet of baryons and pions. The calculation of this work allows us to make various settings by minimum squares, i.e., adjusting our analytical expressions with data pilot can make the comparison between theory and experiment. We found the comparison of our theoretical results with the experiment are in total agreement.
hep-ph/0108167
Ernest Ma
Rathin Adhikari (Jadavpur U and Calcutta U, Kolkata), Ernest Ma (UC Riverside), and G. Rajasekaran (IMSC, Chennai)
Supersymmetric Model of Muon Anomalous Magnetic Moment and Neutrino Masses
10 pages, including 2 figures
Phys.Rev. D65 (2002) 077703
10.1103/PhysRevD.65.077703
UCRHEP-T313 (Aug 2001)
hep-ph
null
We propose the novel lepton-number relationship $L_\tau = L_e + L_\mu$, which is uniquely realized by the interaction $(\hat \nu_e \hat \mu - \hat e \hat \nu_\mu) \hat \tau^c$ in supersymmetry and may account for a possibly large muon anomalous magnetic moment. Neutrino masses (with bimaximal mixing) may be generated from the spontaneous and soft breaking of this lepton symmetry.
[ { "created": "Tue, 21 Aug 2001 18:36:38 GMT", "version": "v1" } ]
2009-11-07
[ [ "Adhikari", "Rathin", "", "Jadavpur U and Calcutta U, Kolkata" ], [ "Ma", "Ernest", "", "UC\n Riverside" ], [ "Rajasekaran", "G.", "", "IMSC, Chennai" ] ]
We propose the novel lepton-number relationship $L_\tau = L_e + L_\mu$, which is uniquely realized by the interaction $(\hat \nu_e \hat \mu - \hat e \hat \nu_\mu) \hat \tau^c$ in supersymmetry and may account for a possibly large muon anomalous magnetic moment. Neutrino masses (with bimaximal mixing) may be generated from the spontaneous and soft breaking of this lepton symmetry.
hep-ph/0608347
Alessandro Strumia
Alessandro Strumia
Baryogenesis via leptogenesis
20 pages. Lectures given at LesHouches 2005 + some original material about "flavored leptogenesis" and "DM/leptogenesis unification"
null
null
null
hep-ph
null
We discuss how leptogenesis can explain the observed baryon asymmetry and summarize attempts of testing leptogenesis. We first perform estimates and discuss the main physics, and later outline the techniques that allow to perform precise computations.
[ { "created": "Thu, 31 Aug 2006 18:54:57 GMT", "version": "v1" } ]
2007-05-23
[ [ "Strumia", "Alessandro", "" ] ]
We discuss how leptogenesis can explain the observed baryon asymmetry and summarize attempts of testing leptogenesis. We first perform estimates and discuss the main physics, and later outline the techniques that allow to perform precise computations.
2011.01061
Ying Li
Xue Leng, Xiao-Long Mu, Zhi-Tian Zou, Ying Li
Investigation of Effects of New Physics in $c\to (s,d)\ell^+\nu_\ell$ Transitions
28 Pages,9 figures
null
10.1088/1674-1137/abf489
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Recent anomalies in decays induced by $b\to c \ell^- \bar\nu_\ell$ transitions raise the question about such phenomena in the $D$ decays induced by $c\to (s,d)\ell^+\nu_\ell$ transitions. In the experimental side, current measurements on the pure leptonic and semileptonic $D$ decays agree with the standard model predictions, such agreements can be used to constrain the new physics (NP) contributions. In this work, we extend the standard model by assuming general effective Hamiltonians describing the $c\to (s,d)\ell^+\nu_\ell$ transitions including the full set of the four-fermion operators. Within the latest experimental data, we perform a minimum $\chi^2$ fit of the Wilson coefficient corresponding to each operator. The results show that the Wilson coefficients of scalar operators in muon sector are at the order of ${\cal O}(10^{-2})$, and others are at the order of ${\cal O}(10^{-3})$. The lepton flavor universality could be violated by the scalar operators. We also calculate the branching fractions, the forward-backward asymmetries and polarizations of final vector mesons and leptons with the fitted Wilson coefficients of scalar and tensor operators. It is found that the pure leptonic decays are very sensitive to the scalar operators. The effects of NP on the semileptonic decays with electron are negligible, while for the semileptonic decays with muon the effects of scalar operators will show up in the forward-backward asymmetries and polarizations of muon of $D \to P\mu^+ \nu_\mu$. The future measurements in BESIII and Belle II experiments will help us to test effects of NP and to further test new physics models.
[ { "created": "Mon, 2 Nov 2020 15:42:46 GMT", "version": "v1" } ]
2021-07-07
[ [ "Leng", "Xue", "" ], [ "Mu", "Xiao-Long", "" ], [ "Zou", "Zhi-Tian", "" ], [ "Li", "Ying", "" ] ]
Recent anomalies in decays induced by $b\to c \ell^- \bar\nu_\ell$ transitions raise the question about such phenomena in the $D$ decays induced by $c\to (s,d)\ell^+\nu_\ell$ transitions. In the experimental side, current measurements on the pure leptonic and semileptonic $D$ decays agree with the standard model predictions, such agreements can be used to constrain the new physics (NP) contributions. In this work, we extend the standard model by assuming general effective Hamiltonians describing the $c\to (s,d)\ell^+\nu_\ell$ transitions including the full set of the four-fermion operators. Within the latest experimental data, we perform a minimum $\chi^2$ fit of the Wilson coefficient corresponding to each operator. The results show that the Wilson coefficients of scalar operators in muon sector are at the order of ${\cal O}(10^{-2})$, and others are at the order of ${\cal O}(10^{-3})$. The lepton flavor universality could be violated by the scalar operators. We also calculate the branching fractions, the forward-backward asymmetries and polarizations of final vector mesons and leptons with the fitted Wilson coefficients of scalar and tensor operators. It is found that the pure leptonic decays are very sensitive to the scalar operators. The effects of NP on the semileptonic decays with electron are negligible, while for the semileptonic decays with muon the effects of scalar operators will show up in the forward-backward asymmetries and polarizations of muon of $D \to P\mu^+ \nu_\mu$. The future measurements in BESIII and Belle II experiments will help us to test effects of NP and to further test new physics models.
1708.07138
Matthias Steinhauser
Peter Marquard, Alexander V. Smirnov, Vladimir A. Smirnov, Matthias Steinhauser, David Wellmann
$(g-2)_\mu$ at four loops in QED
6 pages, Contribution to the proceedings of the International workshop on e+e- collisions from Phi to Psi 2017, v2: references added
null
null
DESY 17-125, TTP17-035
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We review the four-loop QED corrections to the anomalous magnetic moment of the muon. The fermionic contributions with closed electron and tau contributions are discussed. Furthermore, we report on a new independent calculation of the universal four-loop contribution and compare with existing results.
[ { "created": "Wed, 23 Aug 2017 18:06:44 GMT", "version": "v1" }, { "created": "Wed, 20 Sep 2017 10:45:34 GMT", "version": "v2" } ]
2017-09-21
[ [ "Marquard", "Peter", "" ], [ "Smirnov", "Alexander V.", "" ], [ "Smirnov", "Vladimir A.", "" ], [ "Steinhauser", "Matthias", "" ], [ "Wellmann", "David", "" ] ]
We review the four-loop QED corrections to the anomalous magnetic moment of the muon. The fermionic contributions with closed electron and tau contributions are discussed. Furthermore, we report on a new independent calculation of the universal four-loop contribution and compare with existing results.
hep-ph/9409310
null
Enrico Nardi, Esteban Roulet and Daniele Tommasini
New Neutral Gauge Bosons and New Heavy Fermions in the Light of the New LEP Data
12 pages (including two tables), revised version, accepted for publication in Phys. Lett. B. Includes a discussion of the m_t and alpha_s dependence of the bounds on the Z' mass and the fermion mixings
Phys.Lett.B344:225-232,1995
10.1016/0370-2693(95)91542-M
CERN-TH.7443/94, UM-TH-94-34
hep-ph
null
We derive limits on a class of new physics effects that are naturally present in grand unified theories based on extended gauge groups, and in particular in $E_6$ and $SO(10)$ models. We concentrate on $i$) the effects of the mixing of new neutral gauge bosons with the standard $Z_0$; $ii$) the effects of a mixing of the known fermions with new heavy states. We perform a global analysis including all the LEP data on the $Z$ decay widths and asymmetries collected until 1993, the SLC measurement of the left--right asymmetry, the measurement of the $W$ boson mass, various charged current constraints, and the low energy neutral current experiments. We use a top mass value in the range announced by CDF. We derive limits on the $Z_0$--$Z_1$ mixing, which are always $\lsim 0.01$ and are at the level of a few {\it per mille} if some specific model is assumed. Model-dependent theoretical relations between the mixing and the mass of the new gauge boson in most cases require $M_{Z'} > 1\,$TeV. Limits on light--heavy fermion mixings are also largely improved with respect to previous analyses, and are particularly relevant for a class of models that we discuss.
[ { "created": "Wed, 14 Sep 1994 12:22:12 GMT", "version": "v1" }, { "created": "Mon, 12 Dec 1994 16:25:01 GMT", "version": "v2" } ]
2010-11-01
[ [ "Nardi", "Enrico", "" ], [ "Roulet", "Esteban", "" ], [ "Tommasini", "Daniele", "" ] ]
We derive limits on a class of new physics effects that are naturally present in grand unified theories based on extended gauge groups, and in particular in $E_6$ and $SO(10)$ models. We concentrate on $i$) the effects of the mixing of new neutral gauge bosons with the standard $Z_0$; $ii$) the effects of a mixing of the known fermions with new heavy states. We perform a global analysis including all the LEP data on the $Z$ decay widths and asymmetries collected until 1993, the SLC measurement of the left--right asymmetry, the measurement of the $W$ boson mass, various charged current constraints, and the low energy neutral current experiments. We use a top mass value in the range announced by CDF. We derive limits on the $Z_0$--$Z_1$ mixing, which are always $\lsim 0.01$ and are at the level of a few {\it per mille} if some specific model is assumed. Model-dependent theoretical relations between the mixing and the mass of the new gauge boson in most cases require $M_{Z'} > 1\,$TeV. Limits on light--heavy fermion mixings are also largely improved with respect to previous analyses, and are particularly relevant for a class of models that we discuss.
hep-ph/9910499
Nemanja Kaloper
Nemanja Kaloper, Andrew R. Liddle
Dynamics and perturbations in assisted chaotic inflation
10 pages, revtex, 2 figures
Phys.Rev. D61 (2000) 123513
10.1103/PhysRevD.61.123513
SU-ITP-99/45
hep-ph astro-ph gr-qc hep-th
null
On compactification from higher dimensions, a single free massive scalar field gives rise to a set of effective four-dimensional scalar fields, each with a different mass. These can cooperate to drive a period of inflation known as assisted inflation. We analyze the dynamics of the simplest implementation of this idea, paying particular attention to the decoupling of fields from the slow-roll regime as inflation proceeds. Unlike normal models of inflation, the dynamics does not become independent of the initial conditions at late times. In particular, we estimate the density perturbations obtained, which retain a memory of the initial conditions even though a homogeneous, spatially-flat Universe is generated.
[ { "created": "Wed, 27 Oct 1999 01:27:02 GMT", "version": "v1" } ]
2009-10-31
[ [ "Kaloper", "Nemanja", "" ], [ "Liddle", "Andrew R.", "" ] ]
On compactification from higher dimensions, a single free massive scalar field gives rise to a set of effective four-dimensional scalar fields, each with a different mass. These can cooperate to drive a period of inflation known as assisted inflation. We analyze the dynamics of the simplest implementation of this idea, paying particular attention to the decoupling of fields from the slow-roll regime as inflation proceeds. Unlike normal models of inflation, the dynamics does not become independent of the initial conditions at late times. In particular, we estimate the density perturbations obtained, which retain a memory of the initial conditions even though a homogeneous, spatially-flat Universe is generated.
hep-ph/9405380
Geert Jan van Oldenborgh
Jochem Fleischer, Fred Jegerlehner, Karol Kolodziej, Geert Jan van Oldenborgh
EEWW: a generator for $e^+e^- \to W^+W^-$ including one-loop and leading photonic two-loop corrections
13 pages latex with 2 figures ps; also available as http://pss058.psi.ch/preprints/eewwmc.ps; PSI-PR-94-16 (added two references)
Comput.Phys.Commun. 85 (1995) 29-39
10.1016/0010-4655(94)00113-G
null
hep-ph
null
We describe a generator for the process $e^+e^- \to W^+W^-$ including all one-loop and leading log photonic two-loop contributions. It includes polarization of the beam and $W$ bosons, and the possibility to study the effect of anomalous couplings.
[ { "created": "Wed, 25 May 1994 14:23:06 GMT", "version": "v1" }, { "created": "Mon, 30 May 1994 17:19:00 GMT", "version": "v2" } ]
2009-10-28
[ [ "Fleischer", "Jochem", "" ], [ "Jegerlehner", "Fred", "" ], [ "Kolodziej", "Karol", "" ], [ "van Oldenborgh", "Geert Jan", "" ] ]
We describe a generator for the process $e^+e^- \to W^+W^-$ including all one-loop and leading log photonic two-loop contributions. It includes polarization of the beam and $W$ bosons, and the possibility to study the effect of anomalous couplings.
0705.1505
C\'edric Lorc\'e
Lorce Cedric
Theta+ width estimation with nonzero momentum transfer
5 pages
null
null
null
hep-ph
null
We have used the light-cone formulation of Chiral-Quark Soliton Model to estimate the width of the lightest pentaquark Theta+. We have found that the effect of nonzero momentum transfer is important and reduces drastically the width to about 0.43 MeV. This means that this effect is a piece of the small width puzzle of exotic baryons.
[ { "created": "Thu, 10 May 2007 16:22:24 GMT", "version": "v1" } ]
2007-05-23
[ [ "Cedric", "Lorce", "" ] ]
We have used the light-cone formulation of Chiral-Quark Soliton Model to estimate the width of the lightest pentaquark Theta+. We have found that the effect of nonzero momentum transfer is important and reduces drastically the width to about 0.43 MeV. This means that this effect is a piece of the small width puzzle of exotic baryons.
hep-ph/9402218
Michael Earnshaw
Michael A. Earnshaw, Warren B. Perkins
Stability of an electroweak string with a fermion condensate
13 pages, preprint DAMTP 94-9, SWAT/23
Phys.Lett. B328 (1994) 337-345
10.1016/0370-2693(94)91488-5
null
hep-ph
null
A solution of the standard electroweak theory with a single lepton family is constructed, consisting of a cosmic string and a fermion condensate within its core. The stability of this system to small perturbations is examined, and it is found that stability is not enhanced relative to the bare electroweak string. The presence of quark zero modes is shown to violate the existence criteria for embedded defects.
[ { "created": "Thu, 3 Feb 1994 12:43:10 GMT", "version": "v1" } ]
2009-10-28
[ [ "Earnshaw", "Michael A.", "" ], [ "Perkins", "Warren B.", "" ] ]
A solution of the standard electroweak theory with a single lepton family is constructed, consisting of a cosmic string and a fermion condensate within its core. The stability of this system to small perturbations is examined, and it is found that stability is not enhanced relative to the bare electroweak string. The presence of quark zero modes is shown to violate the existence criteria for embedded defects.
1205.5887
Krzysztof A. Meissner
Adam Latosinski, Krzysztof A. Meissner and Hermann Nicolai
(B-L) Symmetry vs. Neutrino Seesaw
13 pages, 1 figure, with additional explanations and clarifications
null
10.1140/epjc/s10052-013-2336-7
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We compute the effective coupling of the Majoron to W bosons at $\cO(\hbar)$ by evaluating the matrix element of the (B-L) current between the vacuum and a $W^+W^-$ state. The (B-L) anomaly vanishes, but the amplitude does not vanish as a result of a UV finite and non-local contribution which is entirely due to the mixing between left-chiral and right-chiral neutrinos. The result shows how anomaly-like couplings may arise in spite of the fact that the (B-L) current remains exactly conserved to all orders in $\hbar$, lending additional support to our previous proposal to identify the Majoron with the axion.
[ { "created": "Sat, 26 May 2012 14:59:09 GMT", "version": "v1" }, { "created": "Fri, 12 Oct 2012 07:53:16 GMT", "version": "v2" } ]
2015-06-05
[ [ "Latosinski", "Adam", "" ], [ "Meissner", "Krzysztof A.", "" ], [ "Nicolai", "Hermann", "" ] ]
We compute the effective coupling of the Majoron to W bosons at $\cO(\hbar)$ by evaluating the matrix element of the (B-L) current between the vacuum and a $W^+W^-$ state. The (B-L) anomaly vanishes, but the amplitude does not vanish as a result of a UV finite and non-local contribution which is entirely due to the mixing between left-chiral and right-chiral neutrinos. The result shows how anomaly-like couplings may arise in spite of the fact that the (B-L) current remains exactly conserved to all orders in $\hbar$, lending additional support to our previous proposal to identify the Majoron with the axion.
hep-ph/9303252
null
H. Lew
A Shadow Matter Universe
11 pages (LaTeX), PURD-TH-93-04
null
null
null
hep-ph
null
The cosmological and astrophysical implications of a shadow matter model which could also have interesting experimental consequences are examined. The model has identical microphysics for both the ordinary and shadow worlds but requires a macroscopic asymmetry from nucleosynthesis constraints. It is proposed that this macroscopic asymmetry can be generated at the quark-hadron phase transition.
[ { "created": "Fri, 12 Mar 1993 20:17:14 GMT", "version": "v1" } ]
2007-05-23
[ [ "Lew", "H.", "" ] ]
The cosmological and astrophysical implications of a shadow matter model which could also have interesting experimental consequences are examined. The model has identical microphysics for both the ordinary and shadow worlds but requires a macroscopic asymmetry from nucleosynthesis constraints. It is proposed that this macroscopic asymmetry can be generated at the quark-hadron phase transition.
2407.03480
Rudnei Ramos
Everlyn Martins, Y. M. P. Gomes, Marcus Benghi Pinto and Rudnei O. Ramos
Testing the equivalence between the planar Gross-Neveu and Thirring models at $N=1$
13 pages, 7 figures
null
null
null
hep-ph cond-mat.other hep-th
http://creativecommons.org/licenses/by/4.0/
It is known that the Fierz identities predict that the Gross-Neveu and Thirring models should be equivalent when describing systems composed of a single fermionic flavor, $N=1$. Here, we consider the planar version of both models within the framework of the optimized perturbation theory at the two loop level, in order to verify if the predicted equivalence emerges explicitly when different temperature and density regimes are considered. At vanishing densities, our results indicate that both models indeed describe exactly the same thermodynamics, provided that $N=1$. However, at finite chemical potentials we find that the $N=1$ Fierz equivalence no longer holds. After examining the relevant free energies, we have identified the contributions which lead to this puzzling discrepancy. Finally, we discuss different frameworks in which this (so far open) problem could be further understood and eventually circumvented.
[ { "created": "Wed, 3 Jul 2024 19:58:37 GMT", "version": "v1" } ]
2024-07-08
[ [ "Martins", "Everlyn", "" ], [ "Gomes", "Y. M. P.", "" ], [ "Pinto", "Marcus Benghi", "" ], [ "Ramos", "Rudnei O.", "" ] ]
It is known that the Fierz identities predict that the Gross-Neveu and Thirring models should be equivalent when describing systems composed of a single fermionic flavor, $N=1$. Here, we consider the planar version of both models within the framework of the optimized perturbation theory at the two loop level, in order to verify if the predicted equivalence emerges explicitly when different temperature and density regimes are considered. At vanishing densities, our results indicate that both models indeed describe exactly the same thermodynamics, provided that $N=1$. However, at finite chemical potentials we find that the $N=1$ Fierz equivalence no longer holds. After examining the relevant free energies, we have identified the contributions which lead to this puzzling discrepancy. Finally, we discuss different frameworks in which this (so far open) problem could be further understood and eventually circumvented.
1907.01476
Mikhail Voloshin
M.B. Voloshin
Some decay properties of hidden-charm pentaquarks as baryon-meson molecules
8 pages, 1 figure
Phys. Rev. D 100, 034020 (2019)
10.1103/PhysRevD.100.034020
FTPI-MINN-19/19, UMN-TH-3828/19
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It is pointed out that the previously suggested interpretation of the hidden-charm pentaquarks $P_c(4312)$, $P_c(4440)$ and $P_c(4457)$ as molecular bound states of $\Sigma_c \bar D$ and $\Sigma_c \bar D^*$ baryon-meson pairs gives rise to specific relations for their decays. In particular, the heavy quark spin symmetry predicts ratios of rates of decays of each of the molecules to $J/\psi p$ and to $\eta_c p$ as well as of the decays to $\Lambda_c \bar D$ and to $\Lambda_c \bar D^*$. Experimental studies of these relations would thus provide an indicative probe of the molecular structure.
[ { "created": "Tue, 2 Jul 2019 16:16:29 GMT", "version": "v1" } ]
2019-08-28
[ [ "Voloshin", "M. B.", "" ] ]
It is pointed out that the previously suggested interpretation of the hidden-charm pentaquarks $P_c(4312)$, $P_c(4440)$ and $P_c(4457)$ as molecular bound states of $\Sigma_c \bar D$ and $\Sigma_c \bar D^*$ baryon-meson pairs gives rise to specific relations for their decays. In particular, the heavy quark spin symmetry predicts ratios of rates of decays of each of the molecules to $J/\psi p$ and to $\eta_c p$ as well as of the decays to $\Lambda_c \bar D$ and to $\Lambda_c \bar D^*$. Experimental studies of these relations would thus provide an indicative probe of the molecular structure.
1906.11835
Lu\'is Ventura
Jo\~ao G. Rosa, Lu\'is B. Ventura
Warm Little Inflaton becomes Dark Energy
6 pages, 3 figures, added references and comments. Comments are welcome
null
10.1016/j.physletb.2019.134984
null
hep-ph astro-ph.CO gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a model where the inflaton field behaves like quintessence at late times, generating the present phase of accelerated expansion. This is achieved within the framework of warm inflation, in particular the Warm Little Inflaton scenario, where the underlying symmetries guarantee a successful inflationary period in a warm regime sustained by dissipative effects without significant backreaction on the scalar potential. This yields a smooth transition into a radiation-dominated epoch, at which point dissipative effects naturally shut down as the temperature drops below the mass of the fermions directly coupled to the inflaton. The post-inflationary dynamics is then analogous to a thawing quintessence scenario, with no kination phase at the end of inflation. Observational signatures of this scenario include the modified consistency relation between the tensor-to-scalar ratio and tensor spectral index typical of warm inflation models, the variation of the dark energy equation of state at low redshifts characteristic of thawing quintessence scenarios, and correlated dark energy isocurvature perturbations.
[ { "created": "Thu, 27 Jun 2019 18:00:00 GMT", "version": "v1" }, { "created": "Mon, 15 Jul 2019 20:58:34 GMT", "version": "v2" } ]
2019-10-23
[ [ "Rosa", "João G.", "" ], [ "Ventura", "Luís B.", "" ] ]
We present a model where the inflaton field behaves like quintessence at late times, generating the present phase of accelerated expansion. This is achieved within the framework of warm inflation, in particular the Warm Little Inflaton scenario, where the underlying symmetries guarantee a successful inflationary period in a warm regime sustained by dissipative effects without significant backreaction on the scalar potential. This yields a smooth transition into a radiation-dominated epoch, at which point dissipative effects naturally shut down as the temperature drops below the mass of the fermions directly coupled to the inflaton. The post-inflationary dynamics is then analogous to a thawing quintessence scenario, with no kination phase at the end of inflation. Observational signatures of this scenario include the modified consistency relation between the tensor-to-scalar ratio and tensor spectral index typical of warm inflation models, the variation of the dark energy equation of state at low redshifts characteristic of thawing quintessence scenarios, and correlated dark energy isocurvature perturbations.
0907.2842
Alexander Khodjamirian
A.Khodjamirian, Ch.Klein, Th.Mannel and N.Offen
Semileptonic charm decays $D \to \pi l \nu_{\l}$ and $D \to K l \nu_l$ from QCD Light-Cone Sum Rules
34 pages, 5 figures
null
10.1103/PhysRevD.80.114005
SI-HEP-2009-06, LPT-09-60
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a new calculation of the $D\to\pi$ and $D \to K$ form factors from QCD light-cone sum rules. The $\overline{MS}$ scheme for the $c$-quark mass is used and the input parameters are updated. The results are $f^+_{D\pi}(0)= 0.67^{+0.10}_{-0.07}$, $f^+_{DK}(0)=0.75^{+0.11}_{-0.08}$ and $f^+_{D\pi}(0)/f^+_{DK}(0)=0.88 \pm 0.05$. Combining the calculated form factors with the latest CLEO data, we obtain $|V_{cd}|=0.225\pm 0.005 \pm 0.003 ^{+0.016}_{-0.012}$ and $|V_{cd}|/|V_{cs}|= 0.236\pm 0.006\pm 0.003\pm 0.013$ where the first and second errors are of experimental origin and the third error is due to the estimated uncertainties of our calculation. We also evaluate the form factors $f^-_{D\pi}$ and $f^-_{DK}$ and predict the slope parameters at $q^2=0$. Furthermore, calculating the form factors from the sum rules at $q^2<0$, we fit them to various parameterizations. After analytic continuation, the shape of the $D\to \pi,K $ form factors in the whole semileptonic region is reproduced, in a good agreement with experiment.
[ { "created": "Thu, 16 Jul 2009 13:51:39 GMT", "version": "v1" } ]
2013-05-29
[ [ "Khodjamirian", "A.", "" ], [ "Klein", "Ch.", "" ], [ "Mannel", "Th.", "" ], [ "Offen", "N.", "" ] ]
We present a new calculation of the $D\to\pi$ and $D \to K$ form factors from QCD light-cone sum rules. The $\overline{MS}$ scheme for the $c$-quark mass is used and the input parameters are updated. The results are $f^+_{D\pi}(0)= 0.67^{+0.10}_{-0.07}$, $f^+_{DK}(0)=0.75^{+0.11}_{-0.08}$ and $f^+_{D\pi}(0)/f^+_{DK}(0)=0.88 \pm 0.05$. Combining the calculated form factors with the latest CLEO data, we obtain $|V_{cd}|=0.225\pm 0.005 \pm 0.003 ^{+0.016}_{-0.012}$ and $|V_{cd}|/|V_{cs}|= 0.236\pm 0.006\pm 0.003\pm 0.013$ where the first and second errors are of experimental origin and the third error is due to the estimated uncertainties of our calculation. We also evaluate the form factors $f^-_{D\pi}$ and $f^-_{DK}$ and predict the slope parameters at $q^2=0$. Furthermore, calculating the form factors from the sum rules at $q^2<0$, we fit them to various parameterizations. After analytic continuation, the shape of the $D\to \pi,K $ form factors in the whole semileptonic region is reproduced, in a good agreement with experiment.
hep-ph/9808251
Smaragda Lola
J. Ellis, G.K. Leontaris, S. Lola and D.V. Nanopoulos
Neutrino Textures in the Light of Super-Kamiokande Data and a Realistic String Model
LaTex 37 pages, with 5 eps figures
Eur.Phys.J.C9:389-408,1999
10.1007/s100529900001
ACT-7/98, CERN-TH/98-216, CTP-TAMU-25/98, IOA-10/1998
hep-ph
null
Motivated by the Super-Kamiokande atmospheric neutrino data, we discuss possible textures for Majorana and Dirac neutrino masses within the see-saw framework. The main purposes of this paper are twofold: first to obtain intuition from a purely phenomenological analysis, and secondly to explore to what extent it may be realized in a specific model. We comment initially on the simplified two-generation case, emphasizing that large mixing is not incompatible with a large hierarchy of mass eigenvalues. We also emphasize that renormalization-group effects may amplify neutrino mixing, presenting semi-analytic expressions for estimating this amplification. Several examples are then given of three-family neutrino mass textures which may also accommodate the persistent solar neutrino deficit, with different assumptions for the neutrino Dirac mass matrices. We comment on a few features of neutrino mass textures arising in models with a U(1) flavour symmetry. Finally, we discuss the possible pattern of neutrino masses in a `realistic' flipped SU(5) model derived from string theory, illustrating how a desirable pattern of mixing may emerge. Both small- or large-angle MSW solutions are possible, whilst a hierarchy of neutrino masses appears more natural than near-degeneracy. This model contains some unanticipated features that may also be relevant in other models: the neutrino Dirac matrices may not be related closely to the quark mass matrices, and the heavy Majorana states may include extra gauge-singlet fields.
[ { "created": "Thu, 6 Aug 1998 16:39:59 GMT", "version": "v1" } ]
2009-09-11
[ [ "Ellis", "J.", "" ], [ "Leontaris", "G. K.", "" ], [ "Lola", "S.", "" ], [ "Nanopoulos", "D. V.", "" ] ]
Motivated by the Super-Kamiokande atmospheric neutrino data, we discuss possible textures for Majorana and Dirac neutrino masses within the see-saw framework. The main purposes of this paper are twofold: first to obtain intuition from a purely phenomenological analysis, and secondly to explore to what extent it may be realized in a specific model. We comment initially on the simplified two-generation case, emphasizing that large mixing is not incompatible with a large hierarchy of mass eigenvalues. We also emphasize that renormalization-group effects may amplify neutrino mixing, presenting semi-analytic expressions for estimating this amplification. Several examples are then given of three-family neutrino mass textures which may also accommodate the persistent solar neutrino deficit, with different assumptions for the neutrino Dirac mass matrices. We comment on a few features of neutrino mass textures arising in models with a U(1) flavour symmetry. Finally, we discuss the possible pattern of neutrino masses in a `realistic' flipped SU(5) model derived from string theory, illustrating how a desirable pattern of mixing may emerge. Both small- or large-angle MSW solutions are possible, whilst a hierarchy of neutrino masses appears more natural than near-degeneracy. This model contains some unanticipated features that may also be relevant in other models: the neutrino Dirac matrices may not be related closely to the quark mass matrices, and the heavy Majorana states may include extra gauge-singlet fields.
hep-ph/9501366
null
Zheng Huang
Disoriented Chiral Condensate
8 pages, Compile with LaTeX. One figure available upon request. Presented at the Beyond Standard Model IV, 13-18 December 1994, Take Tahoe, California
null
null
LBL-36740
hep-ph
null
The current theoretical understanding of disoriented chiral condensate is briefly reviewed. I discuss the basic idea, the formation mechanism and experimental signatures of DCC in high energy collisions.
[ { "created": "Wed, 25 Jan 1995 01:28:02 GMT", "version": "v1" } ]
2016-09-01
[ [ "Huang", "Zheng", "" ] ]
The current theoretical understanding of disoriented chiral condensate is briefly reviewed. I discuss the basic idea, the formation mechanism and experimental signatures of DCC in high energy collisions.
0803.3524
Aurore Courtoy
A. Courtoy and S. Noguera
Pion-Photon TDAs in the NJL Model
To appear in the proceedings of International School of Nuclear Physics: 29th Course: Quarks in Hadrons and Nuclei, Erice, Sicily, Italy, 16-24 Sep 2007
Prog.Part.Nucl.Phys.61:170-172,2008
10.1016/j.ppnp.2007.12.040
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The pion-photon Transition Distribution Amplitudes (TDAs) are studied, treating the pion as a bound state in the sense of Bethe-Salpeter, in the formalism of the NJL model. The results obtained explicitly verify support, sum rules and polynomiality conditions. The role of PCAC is highlighted.
[ { "created": "Tue, 25 Mar 2008 10:53:13 GMT", "version": "v1" } ]
2008-11-26
[ [ "Courtoy", "A.", "" ], [ "Noguera", "S.", "" ] ]
The pion-photon Transition Distribution Amplitudes (TDAs) are studied, treating the pion as a bound state in the sense of Bethe-Salpeter, in the formalism of the NJL model. The results obtained explicitly verify support, sum rules and polynomiality conditions. The role of PCAC is highlighted.
hep-ph/0608120
Andrei Kataev
A.L. Kataev (INR, Moscow)
Reconsidered estimates of the 10th order QED contributions to the muon anomaly
19 pages, LaTeX, some misprints in the text and literature corrected. Results unchaged, to appear in Phys.Rev.D
Phys.Rev.D74:073011,2006
10.1103/PhysRevD.74.073011
null
hep-ph
null
The problem of estimating the 10th order QED corrections to the muon anomalous magnetic moment is reconsidered. The incorporation of the recently improved contributions to the $\alpha^4$ and $\alpha^5$- corrections to $a_{\mu}$ within the renormalization-group inspired scheme-invariant approach leads to the estimate $a_{\mu}^{(10)}\approx 643(\alpha/pi)^5$. It is in good agreement with the estimate $a_{\mu}^{(10)}= 663(20) (\alpha/\pi)^5$, obtained by Kinoshita and Nio from the numerical calculations of 2958 10-th order diagrams, which are considered to be more important than the still uncalculated 6122 10th-order $m_{\mu}/m_e$-dependent vertex graphs, and 12672 5-loop diagrams, responsible for the mass-independent constant contribution both to $a_{\mu}$ and $a_e$. This confirms Kinoshita and Nio guess about dominance of the 10-th order diagrams calculated by them. Comparisons with other estimates of the $\alpha^5$- contributions to $a_{\mu}$, which exist in the literature, are presented.
[ { "created": "Thu, 10 Aug 2006 16:42:29 GMT", "version": "v1" }, { "created": "Wed, 4 Oct 2006 15:54:34 GMT", "version": "v2" } ]
2008-11-26
[ [ "Kataev", "A. L.", "", "INR, Moscow" ] ]
The problem of estimating the 10th order QED corrections to the muon anomalous magnetic moment is reconsidered. The incorporation of the recently improved contributions to the $\alpha^4$ and $\alpha^5$- corrections to $a_{\mu}$ within the renormalization-group inspired scheme-invariant approach leads to the estimate $a_{\mu}^{(10)}\approx 643(\alpha/pi)^5$. It is in good agreement with the estimate $a_{\mu}^{(10)}= 663(20) (\alpha/\pi)^5$, obtained by Kinoshita and Nio from the numerical calculations of 2958 10-th order diagrams, which are considered to be more important than the still uncalculated 6122 10th-order $m_{\mu}/m_e$-dependent vertex graphs, and 12672 5-loop diagrams, responsible for the mass-independent constant contribution both to $a_{\mu}$ and $a_e$. This confirms Kinoshita and Nio guess about dominance of the 10-th order diagrams calculated by them. Comparisons with other estimates of the $\alpha^5$- contributions to $a_{\mu}$, which exist in the literature, are presented.
1002.4137
Zosia A. C. Krusberg
Maria Beltran, Dan Hooper, Edward W. Kolb, Zosia A. C. Krusberg, Tim M. P. Tait
Maverick dark matter at colliders
11 pages, 7 figures
JHEP 1009:037,2010
10.1007/JHEP09(2010)037
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Assuming that dark matter is a weakly interacting massive particle (WIMP) species X produced in the early Universe as a cold thermal relic, we study the collider signal of pp or ppbar -> XXbar + jets and its distinguishability from standard-model background processes associated with jets and missing energy. We assume that the WIMP is the sole particle related to dark matter within reach of the LHC--a "maverick" particle--and that it couples to quarks through a higher dimensional contact interaction. We simulate the WIMP final-state signal XXbar + jet and dominant standard-model (SM) background processes and find that the dark-matter production process results in higher energies for the colored final state partons than do the standard-model background processes, resulting in more QCD radiation and a higher jet multiplicity. As a consequence, the detectable signature of maverick dark matter is an excess over standard-model expectations of events consisting of large missing transverse energy, together with large leading jet transverse momentum and scalar sum of the transverse momenta of the jets. Existing Tevatron data and forthcoming LHC data can constrain (or discover!) maverick dark matter.
[ { "created": "Mon, 22 Feb 2010 16:52:38 GMT", "version": "v1" }, { "created": "Mon, 23 Aug 2010 21:40:15 GMT", "version": "v2" } ]
2010-09-21
[ [ "Beltran", "Maria", "" ], [ "Hooper", "Dan", "" ], [ "Kolb", "Edward W.", "" ], [ "Krusberg", "Zosia A. C.", "" ], [ "Tait", "Tim M. P.", "" ] ]
Assuming that dark matter is a weakly interacting massive particle (WIMP) species X produced in the early Universe as a cold thermal relic, we study the collider signal of pp or ppbar -> XXbar + jets and its distinguishability from standard-model background processes associated with jets and missing energy. We assume that the WIMP is the sole particle related to dark matter within reach of the LHC--a "maverick" particle--and that it couples to quarks through a higher dimensional contact interaction. We simulate the WIMP final-state signal XXbar + jet and dominant standard-model (SM) background processes and find that the dark-matter production process results in higher energies for the colored final state partons than do the standard-model background processes, resulting in more QCD radiation and a higher jet multiplicity. As a consequence, the detectable signature of maverick dark matter is an excess over standard-model expectations of events consisting of large missing transverse energy, together with large leading jet transverse momentum and scalar sum of the transverse momenta of the jets. Existing Tevatron data and forthcoming LHC data can constrain (or discover!) maverick dark matter.
1606.01741
Gorazd Cvetic
Cesar Ayala, Gorazd Cvetic, Antonio Pineda
Mass of the bottom quark from Upsilon(1S) at NNNLO: an update
6 pages; presented at ACAT 2016, 18-22 January 2016, UTFSM, Valparaiso, Chile
null
10.1088/1742-6596/762/1/012063
USM-TH-343
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We update our perturbative determination of MSbar bottom quark mass mb(mb), by including the recently obtained four-loop coefficient in the relation between the pole and MSbar mass. First the renormalon subtracted (RS or RS') mass is determined from the known mass of the Upsilon(1S) meson, where we use the renormalon residue Nm obtained from the asymptotic behavior of the coefficient of the 3-loop static singlet potential. MSbar mass is then obtained using the 4-loop renormalon-free relation between the RS (RS') and MSbar mass. We argue that the effects of the charm quark mass are accounted for by effectively using Nf=3 in the mass relations. The extracted value is mb(mb) = 4222(40) MeV, where the uncertainty is dominated by the renormalization scale dependence.
[ { "created": "Mon, 6 Jun 2016 13:46:57 GMT", "version": "v1" } ]
2016-12-21
[ [ "Ayala", "Cesar", "" ], [ "Cvetic", "Gorazd", "" ], [ "Pineda", "Antonio", "" ] ]
We update our perturbative determination of MSbar bottom quark mass mb(mb), by including the recently obtained four-loop coefficient in the relation between the pole and MSbar mass. First the renormalon subtracted (RS or RS') mass is determined from the known mass of the Upsilon(1S) meson, where we use the renormalon residue Nm obtained from the asymptotic behavior of the coefficient of the 3-loop static singlet potential. MSbar mass is then obtained using the 4-loop renormalon-free relation between the RS (RS') and MSbar mass. We argue that the effects of the charm quark mass are accounted for by effectively using Nf=3 in the mass relations. The extracted value is mb(mb) = 4222(40) MeV, where the uncertainty is dominated by the renormalization scale dependence.
hep-ph/0011395
Daniel Cormier
J. Baacke, D. Cormier, H. J. de Vega and K. Heitmann
Dynamics of O(N) chiral supersymmetry at finite energy density
9 pages, 4 figures
Phys.Lett. B520 (2001) 317-321
10.1016/S0370-2693(01)01168-6
DO-TH-00/18, SUSX-TH-00-021, LPTHE/00-46, LA-00-5852
hep-ph
null
We consider an O(N) version of a massive, interacting, chiral supersymmetry model solved exactly in the large N limit. We demonstrate that the system approaches a stable attractor at high energy densities, corresponding to a non-perturbative state for which the relevant field quanta are massless. The state is one of spontaneously broken O(N), which, due to the influence of supersymmetry, does not become restored at high energies. Introducing soft supersymmetry breaking to the Lagrangian results in scalar masses at the soft breaking scale m_s independent of the mass scale of supersymmetry mu, with even smaller masses for the fermions.
[ { "created": "Thu, 30 Nov 2000 17:50:35 GMT", "version": "v1" }, { "created": "Tue, 10 Jul 2001 09:51:48 GMT", "version": "v2" } ]
2009-10-31
[ [ "Baacke", "J.", "" ], [ "Cormier", "D.", "" ], [ "de Vega", "H. J.", "" ], [ "Heitmann", "K.", "" ] ]
We consider an O(N) version of a massive, interacting, chiral supersymmetry model solved exactly in the large N limit. We demonstrate that the system approaches a stable attractor at high energy densities, corresponding to a non-perturbative state for which the relevant field quanta are massless. The state is one of spontaneously broken O(N), which, due to the influence of supersymmetry, does not become restored at high energies. Introducing soft supersymmetry breaking to the Lagrangian results in scalar masses at the soft breaking scale m_s independent of the mass scale of supersymmetry mu, with even smaller masses for the fermions.
hep-ph/9504388
null
F. S. NAVARRA, M. NIELSEN, C. A. A. NUNES and M. TEIXEIRA
ON THE INTRINSIC CHARM COMPONENT OF THE NUCLEON
9 pages, 2 figures not included, avaiable from the authors
Phys.Rev. D54 (1996) 842-846
10.1103/PhysRevD.54.842
IFUSP/P-1150
hep-ph
null
Using a $\overline D$ meson cloud model we calculate the squared charm radius of the nucleon . The ratio between this squared radius and the ordinary baryon squared radius is identified with the probability of ``seeing'' the intrinsic charm component of the nucleon. Our estimate is compatible with those used to successfully describe the charm production phenomenology.
[ { "created": "Mon, 24 Apr 1995 18:08:16 GMT", "version": "v1" } ]
2009-10-28
[ [ "NAVARRA", "F. S.", "" ], [ "NIELSEN", "M.", "" ], [ "NUNES", "C. A. A.", "" ], [ "TEIXEIRA", "M.", "" ] ]
Using a $\overline D$ meson cloud model we calculate the squared charm radius of the nucleon . The ratio between this squared radius and the ordinary baryon squared radius is identified with the probability of ``seeing'' the intrinsic charm component of the nucleon. Our estimate is compatible with those used to successfully describe the charm production phenomenology.
1911.09551
Junle Pei
Tianjun Li, Junle Pei, Fangzhou Xu, Wenxing Zhang
$SU(3)_C\times SU(3)_L\times U(1)_X$ model from $SU(6)$
null
Phys. Rev. D 102, 016004 (2020)
10.1103/PhysRevD.102.016004
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose the $SU(3)_C\times SU(3)_L\times U(1)_X$ model arising from $SU(6)$ breaking. One family of the Standard Model (SM) fermions arises from two $\bar{6}$ representations and one $15$ representation of $SU(6)$ gauge symmetry. To break the $SU(3)_C\times SU(3)_L\times U(1)_X$ gauge symmetry down to the SM, we introduce three $SU(3)_L$ triplet Higgs fields, where two of them come from the $\bar{6}$ representation while the other one from the $15$ representation. We study the gauge boson masses and Higgs boson mass in detail, and find that the vacuum expectation value (VEV) of the Higgs field for $SU(3)_L\times U(1)_X$ gauge symmetry breaking is around 10 TeV. The neutrino masses and mixing can be generated via the littlest inverse seesaw mechanism. In particular, we have normal hierarchy for neutrino masses and the lightest active neutrino is massless. Also, we consider constraints from the charged lepton flavor changing decays as well. Furthermore, introducing two $SU(3)_L$ adjoint fermions, one $SU(3)_C$ adjoint scalar, and one $SU(3)_L$ triplet scalar, we can achieve gauge coupling unification within 1\%. These extra particles can provide a dark matter candidate as well.
[ { "created": "Thu, 21 Nov 2019 15:46:07 GMT", "version": "v1" }, { "created": "Sun, 19 Jul 2020 10:41:57 GMT", "version": "v2" }, { "created": "Fri, 20 Nov 2020 14:50:13 GMT", "version": "v3" } ]
2020-11-23
[ [ "Li", "Tianjun", "" ], [ "Pei", "Junle", "" ], [ "Xu", "Fangzhou", "" ], [ "Zhang", "Wenxing", "" ] ]
We propose the $SU(3)_C\times SU(3)_L\times U(1)_X$ model arising from $SU(6)$ breaking. One family of the Standard Model (SM) fermions arises from two $\bar{6}$ representations and one $15$ representation of $SU(6)$ gauge symmetry. To break the $SU(3)_C\times SU(3)_L\times U(1)_X$ gauge symmetry down to the SM, we introduce three $SU(3)_L$ triplet Higgs fields, where two of them come from the $\bar{6}$ representation while the other one from the $15$ representation. We study the gauge boson masses and Higgs boson mass in detail, and find that the vacuum expectation value (VEV) of the Higgs field for $SU(3)_L\times U(1)_X$ gauge symmetry breaking is around 10 TeV. The neutrino masses and mixing can be generated via the littlest inverse seesaw mechanism. In particular, we have normal hierarchy for neutrino masses and the lightest active neutrino is massless. Also, we consider constraints from the charged lepton flavor changing decays as well. Furthermore, introducing two $SU(3)_L$ adjoint fermions, one $SU(3)_C$ adjoint scalar, and one $SU(3)_L$ triplet scalar, we can achieve gauge coupling unification within 1\%. These extra particles can provide a dark matter candidate as well.
2307.10014
Gregory Patellis
Gregory Patellis, Werner Porod and George Zoupanos
Split NMSSM from dimensional reduction of a $10D$, $\mathcal{N}=1$ $E_8$ over $SU(3)/U(1)\times U(1)\times Z_3$
18 pages, 3 figures
null
null
CERN-TH-2023-124
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We examine an extension of the Standard Model which results from a $10D$, $\mathcal{N}=1$, $E_8$ gauge theory. The theory is dimensionally reduced over a $M_4 \times B_0/ \mathbf{Z}_3 $ space, where $B_0$ is the nearly-K\"ahler manifold $SU(3)/U(1) \times U(1)$ and $\mathbf{Z}_3$ is a freely acting discrete group on $B_0$ that triggers a Wilson flux breaking, leading to an $\mathcal{N}=1$, $SU(3)^3\times U(1)^2$ effective theory in $4D$. At lower energies we are left with the Split NMSSM. Its 2-loop analysis yields third generation quark and light Higgs masses within the experimental limits and predicts a neutralino LSP mass $<800$ GeV.
[ { "created": "Wed, 19 Jul 2023 14:53:08 GMT", "version": "v1" } ]
2023-07-20
[ [ "Patellis", "Gregory", "" ], [ "Porod", "Werner", "" ], [ "Zoupanos", "George", "" ] ]
We examine an extension of the Standard Model which results from a $10D$, $\mathcal{N}=1$, $E_8$ gauge theory. The theory is dimensionally reduced over a $M_4 \times B_0/ \mathbf{Z}_3 $ space, where $B_0$ is the nearly-K\"ahler manifold $SU(3)/U(1) \times U(1)$ and $\mathbf{Z}_3$ is a freely acting discrete group on $B_0$ that triggers a Wilson flux breaking, leading to an $\mathcal{N}=1$, $SU(3)^3\times U(1)^2$ effective theory in $4D$. At lower energies we are left with the Split NMSSM. Its 2-loop analysis yields third generation quark and light Higgs masses within the experimental limits and predicts a neutralino LSP mass $<800$ GeV.
hep-ph/0007220
Zenghui Yu
M. Chaichian (1,2), K. Huitu (1) and Z.-H. Yu (1,2) ((1) Helsinki Institute of Physics (2) Department of Physics, University of Helsinki, Finland)
R-parity violation in $(t+\bar t)\tilde g$ production at LHC and Tevatron
12 pages, 8 figures
Phys.Lett.B490:87-98,2000
10.1016/S0370-2693(00)00881-9
HIP-2000-32/TH
hep-ph
null
We study the production of $(t+\bar{t}) \tilde{g}$ at the hadron colliders in an R-parity ($R_{p}$) violating supersymmetric model. This process provides us with information not only about $R_{p}$ violation, but may also help us in detecting the supersymmetry itself. It is possible to detect an $R_{p}$ violating signal (with single gluino production) at the future hadron colliders, such as Fermilab Tevatron Run II or CERN Large Hadron Collider (LHC), if the parameters in the supersymmetric $\rlap/ R_{p}$ interactions are not too small, e.g. for $m_{\tilde{g}}=1$ TeV, $\lambda^{''}=0.1$, still hundreds of events are produced at LHC with luminosity $30 fb^{-1}$. Even if we could not detect a signal of $ \rlap/R_{p}$ in the experiment, we get stringent constraints on the heavy flavour $\rlap/R_{p}$ couplings. In addition to the minimal supersymmetric standard model we have also considered some models with a heavy gluino as the lightest supersymmetric particle.
[ { "created": "Thu, 20 Jul 2000 08:32:35 GMT", "version": "v1" } ]
2011-03-23
[ [ "Chaichian", "M.", "" ], [ "Huitu", "K.", "" ], [ "Yu", "Z. -H.", "" ] ]
We study the production of $(t+\bar{t}) \tilde{g}$ at the hadron colliders in an R-parity ($R_{p}$) violating supersymmetric model. This process provides us with information not only about $R_{p}$ violation, but may also help us in detecting the supersymmetry itself. It is possible to detect an $R_{p}$ violating signal (with single gluino production) at the future hadron colliders, such as Fermilab Tevatron Run II or CERN Large Hadron Collider (LHC), if the parameters in the supersymmetric $\rlap/ R_{p}$ interactions are not too small, e.g. for $m_{\tilde{g}}=1$ TeV, $\lambda^{''}=0.1$, still hundreds of events are produced at LHC with luminosity $30 fb^{-1}$. Even if we could not detect a signal of $ \rlap/R_{p}$ in the experiment, we get stringent constraints on the heavy flavour $\rlap/R_{p}$ couplings. In addition to the minimal supersymmetric standard model we have also considered some models with a heavy gluino as the lightest supersymmetric particle.
hep-ph/0409010
Robert Harlander
Robert V. Harlander, Matthias Steinhauser
Supersymmetric Higgs production in gluon fusion at next-to-leading order
27 pages, LaTeX, 31 embedded PostScript-files; v2: typos corrected, reformatted in JHEP style; accepted for publication in JHEP
JHEP0409:066,2004
10.1088/1126-6708/2004/09/066
DESY 04-150, TTP 04-19
hep-ph
null
The next-to-leading order (NLO) QCD corrections to the production and decay rate of a Higgs boson are computed within the framework of the Minimal Supersymmetric Standard Model (MSSM). The calculation is based on an effective theory for light and intermediate mass Higgs bosons. We provide a Fortran routine for the numerical evaluation of the coefficient function. For most of the MSSM parameter space, the relative size of the NLO corrections is typically of the order of 5% smaller than the Standard Model value. We exemplify the numerical results for two scenarios: the benchmark point SPS1a, and a parameter region where the gluon-Higgs coupling at leading order is very small due to a cancellation of the squark and quark contributions.
[ { "created": "Wed, 1 Sep 2004 13:29:42 GMT", "version": "v1" }, { "created": "Wed, 29 Sep 2004 08:03:09 GMT", "version": "v2" } ]
2008-11-26
[ [ "Harlander", "Robert V.", "" ], [ "Steinhauser", "Matthias", "" ] ]
The next-to-leading order (NLO) QCD corrections to the production and decay rate of a Higgs boson are computed within the framework of the Minimal Supersymmetric Standard Model (MSSM). The calculation is based on an effective theory for light and intermediate mass Higgs bosons. We provide a Fortran routine for the numerical evaluation of the coefficient function. For most of the MSSM parameter space, the relative size of the NLO corrections is typically of the order of 5% smaller than the Standard Model value. We exemplify the numerical results for two scenarios: the benchmark point SPS1a, and a parameter region where the gluon-Higgs coupling at leading order is very small due to a cancellation of the squark and quark contributions.
1909.12845
Ranjan Laha
Jeff A. Dror, Ranjan Laha, and Toby Opferkuch
Probing muonic forces with neutron star binaries
v2: 12 pages, 5 figures. Discussion lengthened and typos corrected. Conclusions unchanged. Matches journal version
Phys. Rev. D 102, 023005 (2020)
10.1103/PhysRevD.102.023005
CERN-TH-2019-150
hep-ph astro-ph.CO astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We show that gravitational wave emission from neutron star binaries can be used to discover any generic long-ranged muonic force due to the large inevitable abundance of muons inside neutron stars. As a minimal consistent example, we focus on a gauged U(1)$_{L_\mu - L_\tau}$ symmetry. In pulsar binaries, such U(1)$_{L_\mu - L_\tau}$ vectors induce an anomalously fast decay of the orbital period through the emission of dipole radiation. We study a range of different pulsar binaries, finding the most powerful constraints for vector masses below ${\cal O}(10^{-18} {\rm eV})$. For merging binaries the presence of muons in neutron stars can result in dipole radiation as well as a modification of the chirp mass during the inspiral phase. We make projections for a prospective search using both the GW170817 and S190814bv events and find that current data can discover light vectors with masses below ${\cal O}(10^{-10} {\rm eV})$. In both cases, the limits attainable with neutron stars reach gauge coupling $g^\prime\lesssim 10^{-20}$, which are many orders of magnitude stronger than previous constraints. We also show projections for next generation experiments, such as Einstein Telescope and Cosmic Explorer.
[ { "created": "Fri, 27 Sep 2019 18:00:01 GMT", "version": "v1" }, { "created": "Thu, 9 Jul 2020 14:16:37 GMT", "version": "v2" } ]
2020-07-14
[ [ "Dror", "Jeff A.", "" ], [ "Laha", "Ranjan", "" ], [ "Opferkuch", "Toby", "" ] ]
We show that gravitational wave emission from neutron star binaries can be used to discover any generic long-ranged muonic force due to the large inevitable abundance of muons inside neutron stars. As a minimal consistent example, we focus on a gauged U(1)$_{L_\mu - L_\tau}$ symmetry. In pulsar binaries, such U(1)$_{L_\mu - L_\tau}$ vectors induce an anomalously fast decay of the orbital period through the emission of dipole radiation. We study a range of different pulsar binaries, finding the most powerful constraints for vector masses below ${\cal O}(10^{-18} {\rm eV})$. For merging binaries the presence of muons in neutron stars can result in dipole radiation as well as a modification of the chirp mass during the inspiral phase. We make projections for a prospective search using both the GW170817 and S190814bv events and find that current data can discover light vectors with masses below ${\cal O}(10^{-10} {\rm eV})$. In both cases, the limits attainable with neutron stars reach gauge coupling $g^\prime\lesssim 10^{-20}$, which are many orders of magnitude stronger than previous constraints. We also show projections for next generation experiments, such as Einstein Telescope and Cosmic Explorer.
2111.01150
Geraldine Servant
Yann Gouttenoire, Geraldine Servant and Peera Simakachorn
Kination cosmology from scalar fields and gravitational-wave signatures
95 pages, 49 figures (main text without references) + 35 pages, 11 figures (appendices). v2: Fixed model-dependent part, enlarged region of parameter space for thermal damping. Plots updated accordingly. Clarifications also added in model-independent part. Link to Youtube video: https://www.youtube.com/watch?v=RdCAgcvfFy0
null
null
DESY 21-134
hep-ph astro-ph.CO
http://creativecommons.org/licenses/by/4.0/
Kination denotes an era in the cosmological history corresponding to an equation of state $\omega=+1$ such that the total energy density of the universe redshifts as the sixth inverse power of the scale factor. This arises if the universe is dominated by the kinetic energy of a scalar field. It has often been motivated in the literature as an era following inflation, taking place before the radiation era. In this paper, we review instead the possibility that kination is disconnected from primordial inflation and occurs much later, inside the Standard Model radiation era. We study the implications on all main sources of primordial gravitational waves. We show how this leads to very distinctive peaked spectra in the stochastic background of long-lasting cosmological sources of gravitational waves, namely the irreducible gravitational waves from inflation, and gravitational waves from cosmic strings, both local and global, with promising observational prospects. We present model-independent signatures and detectability predictions at SKA, LIGO, LISA, ET, CE, BBO, as a function of the energy scale and duration of the kination era. We then argue that such intermediate kination era is in fact symptomatic in a large class of axion models. We analyse in details the scalar field dynamics, the working conditions and constraints in the underlying models. We present the gravitational-wave predictions as a function of particle physics parameters. We derive the general relation between the gravitational-wave signal and the axion dark matter abundance as well as the baryon asymmetry. We investigate the predictions for the special case of the QCD axion. The key message is that gravitational-waves of primordial origin represent an alternative experimental probe of axion models.
[ { "created": "Mon, 1 Nov 2021 18:00:02 GMT", "version": "v1" }, { "created": "Sun, 1 May 2022 20:56:44 GMT", "version": "v2" } ]
2022-05-03
[ [ "Gouttenoire", "Yann", "" ], [ "Servant", "Geraldine", "" ], [ "Simakachorn", "Peera", "" ] ]
Kination denotes an era in the cosmological history corresponding to an equation of state $\omega=+1$ such that the total energy density of the universe redshifts as the sixth inverse power of the scale factor. This arises if the universe is dominated by the kinetic energy of a scalar field. It has often been motivated in the literature as an era following inflation, taking place before the radiation era. In this paper, we review instead the possibility that kination is disconnected from primordial inflation and occurs much later, inside the Standard Model radiation era. We study the implications on all main sources of primordial gravitational waves. We show how this leads to very distinctive peaked spectra in the stochastic background of long-lasting cosmological sources of gravitational waves, namely the irreducible gravitational waves from inflation, and gravitational waves from cosmic strings, both local and global, with promising observational prospects. We present model-independent signatures and detectability predictions at SKA, LIGO, LISA, ET, CE, BBO, as a function of the energy scale and duration of the kination era. We then argue that such intermediate kination era is in fact symptomatic in a large class of axion models. We analyse in details the scalar field dynamics, the working conditions and constraints in the underlying models. We present the gravitational-wave predictions as a function of particle physics parameters. We derive the general relation between the gravitational-wave signal and the axion dark matter abundance as well as the baryon asymmetry. We investigate the predictions for the special case of the QCD axion. The key message is that gravitational-waves of primordial origin represent an alternative experimental probe of axion models.
1310.0243
John Gracey
J.M. Bell, J.A. Gracey
MOM renormalization group functions in the maximal abelian gauge
32 latex pages, anc directory contains txt file with beta-functions, anomalous dimensions, coupling constant mappings, conversion functions and amplitudes in analytic form
null
10.1103/PhysRevD.88.085027
LTH 985
hep-ph hep-lat
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The one loop 3-point vertex functions of QCD in the maximal abelian gauge (MAG) are evaluated at the fully symmetric point at one loop. As a consequence the theory is renormalized in the various momentum (MOM) schemes which are defined by the trivalent vertices, as well as in the MSbar scheme. From these the two loop renormalization group functions in the MOM schemes are derived using the one loop conversion functions. In parallel we repeat the analysis for the Curci-Ferrari gauge which corresponds to the MAG in a specific limit. The relation between the Lambda parameters in different schemes is also provided.
[ { "created": "Tue, 1 Oct 2013 11:16:45 GMT", "version": "v1" } ]
2015-06-17
[ [ "Bell", "J. M.", "" ], [ "Gracey", "J. A.", "" ] ]
The one loop 3-point vertex functions of QCD in the maximal abelian gauge (MAG) are evaluated at the fully symmetric point at one loop. As a consequence the theory is renormalized in the various momentum (MOM) schemes which are defined by the trivalent vertices, as well as in the MSbar scheme. From these the two loop renormalization group functions in the MOM schemes are derived using the one loop conversion functions. In parallel we repeat the analysis for the Curci-Ferrari gauge which corresponds to the MAG in a specific limit. The relation between the Lambda parameters in different schemes is also provided.
hep-ph/9511282
null
Bing-Lin Young
Some Phenomenology of the top quark with non-standard couplings
5 pages, Latex, figures available by request
null
null
null
hep-ph
null
In this talk I will use effective lagrangian and discuss possible new physics associated with top quark.
[ { "created": "Thu, 9 Nov 1995 16:49:38 GMT", "version": "v1" }, { "created": "Mon, 20 Nov 1995 17:32:39 GMT", "version": "v2" } ]
2008-02-03
[ [ "Young", "Bing-Lin", "" ] ]
In this talk I will use effective lagrangian and discuss possible new physics associated with top quark.
2108.00869
Meng-He Wu
Yi Ling, Yuxuan Liu, Sai Wang and Meng-He Wu
The implications of gamma-ray photons from LHAASO on Lorentz symmetry
6 pages, 3 figures and 1 table
Chin.Phys.C 46 (2022) 5, 055101
10.1088/1674-1137/ac4704
null
hep-ph astro-ph.HE gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Large High Altitude Air Shower Observatory (LHAASO) has reported the measurement of photons with high energy up to 1.42 PeV from twelve gamma-ray sources. We are concerned with the implications of LHAASO data on the fate of Lorenz symmetry at such high energy level, thus we consider the interaction of the gamma ray with those photons in cosmic microwave background (CMB), and compute the optical depth, the mean free path as well as the survival probability for photons from all these gamma-ray sources. Employing the threshold value predicted by the standard special relativity, it is found that the lowest survival probability for observed gamma ray photons is about 0.60, which is a fairly high value and implies that abundant photons with energy above the threshold value may reach the Earth without Lorentz symmetry violation. We conclude that it is still far to argue that the Lorentz symmetry would be violated due to the present observations from LHAASO.
[ { "created": "Mon, 2 Aug 2021 13:00:02 GMT", "version": "v1" }, { "created": "Mon, 2 May 2022 14:37:48 GMT", "version": "v2" } ]
2022-05-03
[ [ "Ling", "Yi", "" ], [ "Liu", "Yuxuan", "" ], [ "Wang", "Sai", "" ], [ "Wu", "Meng-He", "" ] ]
The Large High Altitude Air Shower Observatory (LHAASO) has reported the measurement of photons with high energy up to 1.42 PeV from twelve gamma-ray sources. We are concerned with the implications of LHAASO data on the fate of Lorenz symmetry at such high energy level, thus we consider the interaction of the gamma ray with those photons in cosmic microwave background (CMB), and compute the optical depth, the mean free path as well as the survival probability for photons from all these gamma-ray sources. Employing the threshold value predicted by the standard special relativity, it is found that the lowest survival probability for observed gamma ray photons is about 0.60, which is a fairly high value and implies that abundant photons with energy above the threshold value may reach the Earth without Lorentz symmetry violation. We conclude that it is still far to argue that the Lorentz symmetry would be violated due to the present observations from LHAASO.
1905.01872
Gergely G\'abor Barnaf\"oldi
P\'eter P\'osfay, Gergely G\'abor Barnaf\"oldi, Antal Jakov\'ac
Estimating the variation of neutron star observables by symmetric dense nuclear matter properties
14 pages, 5 figures 2 tables
null
null
null
hep-ph astro-ph.HE nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Recent multi-channel astrophysics observations and the soon-to-be published new measured electromagnetic and gravitation data provide information on the inner structure of the compact stars. These macroscopic observations can significantly increase our knowledge on the neutron star enteriors, providing constraints on the microscopic physical properties. On the other hand, due to the masquarade problem, there are still uncertainties on the various nuclear-matter models and their parameters as well. Calculating the properties of the dense nuclear matter, effective field theories are the most widely-used tools. However the values of the microscopical parameters need to be set consistently to the nuclear and astrophysical measurements. In this work we investigate how uncertainties are induced by the variation of the microscopical parameters. We use a symmetric nuclear matter in an extended $\sigma$-$\omega$ model. We calculate the dense matter equation of state and give the mass-radius diagram. We present that the Landau mass and compressibility modulus of the nuclear matter have definite linear relation to the maximum mass of a Schwarzschild neutron star.
[ { "created": "Mon, 6 May 2019 08:22:27 GMT", "version": "v1" } ]
2019-05-07
[ [ "Pósfay", "Péter", "" ], [ "Barnaföldi", "Gergely Gábor", "" ], [ "Jakovác", "Antal", "" ] ]
Recent multi-channel astrophysics observations and the soon-to-be published new measured electromagnetic and gravitation data provide information on the inner structure of the compact stars. These macroscopic observations can significantly increase our knowledge on the neutron star enteriors, providing constraints on the microscopic physical properties. On the other hand, due to the masquarade problem, there are still uncertainties on the various nuclear-matter models and their parameters as well. Calculating the properties of the dense nuclear matter, effective field theories are the most widely-used tools. However the values of the microscopical parameters need to be set consistently to the nuclear and astrophysical measurements. In this work we investigate how uncertainties are induced by the variation of the microscopical parameters. We use a symmetric nuclear matter in an extended $\sigma$-$\omega$ model. We calculate the dense matter equation of state and give the mass-radius diagram. We present that the Landau mass and compressibility modulus of the nuclear matter have definite linear relation to the maximum mass of a Schwarzschild neutron star.
1401.5944
Yuta Orikasa
Michio Hashimoto, Satoshi Iso, Yuta Orikasa
Radiative Symmetry Breaking from Flat Potential in various U(1)' models
14 pages, 5 figures; references added, to appear in PRD
Phys. Rev. D 89, 056010 (2014)
10.1103/PhysRevD.89.056010
KEK-TH 1700, OU-HET 805
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate a radiative electroweak gauge symmetry breaking scenario via the Coleman-Weinberg mechanism starting from a completely flat Higgs potential at the Planck scale ("flatland scenario"). In our previous paper, we showed that the flatland scenario is possible only when an inequality K<1 among the coefficients of the beta functions is satisfied. In this paper, we calculate the number K in various models with an extra U(1) gauge sector in addition to the SM particles. We also show the renormalization group (RG) behaviors of a couple of the models as examples.
[ { "created": "Thu, 23 Jan 2014 11:40:44 GMT", "version": "v1" }, { "created": "Wed, 29 Jan 2014 13:02:19 GMT", "version": "v2" }, { "created": "Thu, 27 Feb 2014 14:26:34 GMT", "version": "v3" } ]
2014-03-26
[ [ "Hashimoto", "Michio", "" ], [ "Iso", "Satoshi", "" ], [ "Orikasa", "Yuta", "" ] ]
We investigate a radiative electroweak gauge symmetry breaking scenario via the Coleman-Weinberg mechanism starting from a completely flat Higgs potential at the Planck scale ("flatland scenario"). In our previous paper, we showed that the flatland scenario is possible only when an inequality K<1 among the coefficients of the beta functions is satisfied. In this paper, we calculate the number K in various models with an extra U(1) gauge sector in addition to the SM particles. We also show the renormalization group (RG) behaviors of a couple of the models as examples.
2305.11958
Shohei Okawa
Luca Di Luzio, Maurizio Giannotti, Federico Mescia, Enrico Nardi, Shohei Okawa, Gioacchino Piazza
Running effects on QCD axion phenomenology
15 pages, 6 figures, 4 tables. v2: journal version
Phys.Rev.D 108 (2023) 11, 115004
10.1103/PhysRevD.108.115004
null
hep-ph astro-ph.CO astro-ph.HE
http://creativecommons.org/licenses/by/4.0/
We study the impact of renormalization group effects on QCD axion phenomenology. Focusing on the DFSZ model, we argue that the relevance of running effects for the axion couplings crucially depends on the scale where the heavier Higgs scalars are integrated out. We study the impact of these effects on astrophysical and cosmological bounds as well as on the sensitivity of helioscopes experiments such as IAXO and XENONnT, showing that they can be sizable even in the most conservative case in which the two Higgs doublets remain as light as the TeV scale. We provide simple analytical expressions that accurately fit the numerical solutions of the renormalization group equations as a function of the mass scale of the heavy scalars.
[ { "created": "Fri, 19 May 2023 18:45:35 GMT", "version": "v1" }, { "created": "Wed, 27 Dec 2023 03:30:22 GMT", "version": "v2" } ]
2023-12-29
[ [ "Di Luzio", "Luca", "" ], [ "Giannotti", "Maurizio", "" ], [ "Mescia", "Federico", "" ], [ "Nardi", "Enrico", "" ], [ "Okawa", "Shohei", "" ], [ "Piazza", "Gioacchino", "" ] ]
We study the impact of renormalization group effects on QCD axion phenomenology. Focusing on the DFSZ model, we argue that the relevance of running effects for the axion couplings crucially depends on the scale where the heavier Higgs scalars are integrated out. We study the impact of these effects on astrophysical and cosmological bounds as well as on the sensitivity of helioscopes experiments such as IAXO and XENONnT, showing that they can be sizable even in the most conservative case in which the two Higgs doublets remain as light as the TeV scale. We provide simple analytical expressions that accurately fit the numerical solutions of the renormalization group equations as a function of the mass scale of the heavy scalars.
hep-ph/0211397
Paolo Gondolo
Paolo Gondolo, Katherine Freese
An Accelerating Universe from Dark Matter Interactions with Negative Pressure
12 pages
null
null
CWRU-P17-02, NSF-ITP-02-173
hep-ph
null
As an explanation for the acceleration of the universe, we propose dark matter with self-interactions characterized by a negative pressure; there is no vacuum energy whatsoever in this Cardassian model. These self-interactions may arise due to a long-range "fifth force" which grows with the distance between particles. We use the ordinary Friedmann equation, $H^2 = 8 \pi G \rho/3$, and take the energy density to be the sum of two terms: $\rho = \rho_M + \rho_K$. Here $\rho_M \equiv m n_M$ is the ordinary mass density and $\rho_K \equiv \rho_K(\rho_M)$ is a new interaction term which depends only on the matter density. For example, in the original version of the Cardassian model, $\rho_K = b \rho_M^n$ with $n<2/3$; other examples are studied as well. We use the ordinary four-dimensional Einstein's equations $G_{\mu\nu} = 8 \pi G T_{\mu\nu} $ and assume a perfect fluid form for the energy momentum tensor. Given this ansatz, we can compute the accompanying pressure, and use the conservation of the energy-momentum tensor to obtain modified forms of the Euler's equation, Poisson equation, and continuity equation. With this fully relativistic description, one will then be able to compute growth of density perturbations, effects on the Cosmic Background Radiation, and other effects with an eye to observational tests of the model.
[ { "created": "Tue, 26 Nov 2002 15:53:45 GMT", "version": "v1" } ]
2007-05-23
[ [ "Gondolo", "Paolo", "" ], [ "Freese", "Katherine", "" ] ]
As an explanation for the acceleration of the universe, we propose dark matter with self-interactions characterized by a negative pressure; there is no vacuum energy whatsoever in this Cardassian model. These self-interactions may arise due to a long-range "fifth force" which grows with the distance between particles. We use the ordinary Friedmann equation, $H^2 = 8 \pi G \rho/3$, and take the energy density to be the sum of two terms: $\rho = \rho_M + \rho_K$. Here $\rho_M \equiv m n_M$ is the ordinary mass density and $\rho_K \equiv \rho_K(\rho_M)$ is a new interaction term which depends only on the matter density. For example, in the original version of the Cardassian model, $\rho_K = b \rho_M^n$ with $n<2/3$; other examples are studied as well. We use the ordinary four-dimensional Einstein's equations $G_{\mu\nu} = 8 \pi G T_{\mu\nu} $ and assume a perfect fluid form for the energy momentum tensor. Given this ansatz, we can compute the accompanying pressure, and use the conservation of the energy-momentum tensor to obtain modified forms of the Euler's equation, Poisson equation, and continuity equation. With this fully relativistic description, one will then be able to compute growth of density perturbations, effects on the Cosmic Background Radiation, and other effects with an eye to observational tests of the model.
1312.0448
Andrej Arbuzov
A.B. Arbuzov and T.V. Kopylova
Off-mass-shell muon anomalous magnetic moment
5 pages
Phys. Part. Nucl. Lett. 11, 339-341 (2014)
10.1134/S1547477114040086
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Interaction of charged leptons with photons is considered for the case when one of the lepton legs is off the mass shell. The effect due to off-mass-shell shift in the anomalous magnetic moment is computed within one-loop approximation. Possible contributions of this effect in the muon $g-2$ measurements are discussed.
[ { "created": "Mon, 2 Dec 2013 13:36:33 GMT", "version": "v1" } ]
2017-08-11
[ [ "Arbuzov", "A. B.", "" ], [ "Kopylova", "T. V.", "" ] ]
Interaction of charged leptons with photons is considered for the case when one of the lepton legs is off the mass shell. The effect due to off-mass-shell shift in the anomalous magnetic moment is computed within one-loop approximation. Possible contributions of this effect in the muon $g-2$ measurements are discussed.
hep-ph/0310119
Evgeny Akhmedov
Evgeny Akhmedov and Takeshi Fukuyama
Supernova prompt neutronization neutrinos and neutrino magnetic moments
LaTex, 25 pages, 3 figures. v4: Discussion section expanded, references added. Matches the published version
JCAP0312:007,2003
10.1088/1475-7516/2003/12/007
null
hep-ph astro-ph hep-ex
null
It is shown that the combined action of spin-flavor conversions of supernova neutrinos due to the interactions of their Majorana-type transition magnetic moments with the supernova magnetic fields and flavor conversions due to the mass mixing can lead to the transformation of \nu_e born in the neutronization process into their antiparticles \bar{\nu}_e. Such an effect would have a clear experimental signature and its observation would be a smoking gun evidence for the neutrino transition magnetic moments. It would also signify the leptonic mixing parameter |U_{e3}| in excess of 10^{-2}.
[ { "created": "Thu, 9 Oct 2003 17:48:11 GMT", "version": "v1" }, { "created": "Tue, 28 Oct 2003 18:12:04 GMT", "version": "v2" }, { "created": "Fri, 31 Oct 2003 14:08:09 GMT", "version": "v3" }, { "created": "Mon, 15 Mar 2004 16:26:59 GMT", "version": "v4" } ]
2008-11-26
[ [ "Akhmedov", "Evgeny", "" ], [ "Fukuyama", "Takeshi", "" ] ]
It is shown that the combined action of spin-flavor conversions of supernova neutrinos due to the interactions of their Majorana-type transition magnetic moments with the supernova magnetic fields and flavor conversions due to the mass mixing can lead to the transformation of \nu_e born in the neutronization process into their antiparticles \bar{\nu}_e. Such an effect would have a clear experimental signature and its observation would be a smoking gun evidence for the neutrino transition magnetic moments. It would also signify the leptonic mixing parameter |U_{e3}| in excess of 10^{-2}.
hep-ph/0211078
Ignacio Bediaga
Ignacio Bediaga and Jussara M. de Miranda
Complex amplitude phase motion in Dalitz plot heavy meson three body decay
To appear in Physics Letters B
Phys.Lett. B550 (2002) 135-139
10.1016/S0370-2693(02)02983-0
null
hep-ph hep-ex
null
We propose a method to determine the phase motion of a complex amplitude in three body heavy meson decays. We show that the phase variation of a complex amplitude can be directly revealed through the interference observed in the Dalitz Plot region where it crosses with a well established resonant state. This method could be applied to the decays \d3pi and $D^+\to K^-\pi^+\pi^+$, to determine whether the low mass states $\sigma$ and $\kappa$, suggested by E791, have phase motions compatible with resonances.
[ { "created": "Wed, 6 Nov 2002 16:30:19 GMT", "version": "v1" } ]
2009-11-07
[ [ "Bediaga", "Ignacio", "" ], [ "de Miranda", "Jussara M.", "" ] ]
We propose a method to determine the phase motion of a complex amplitude in three body heavy meson decays. We show that the phase variation of a complex amplitude can be directly revealed through the interference observed in the Dalitz Plot region where it crosses with a well established resonant state. This method could be applied to the decays \d3pi and $D^+\to K^-\pi^+\pi^+$, to determine whether the low mass states $\sigma$ and $\kappa$, suggested by E791, have phase motions compatible with resonances.
1907.11595
Haiying Cai
Haiying Cai
Radiative neutrino model with semi-annihilation dark matter
27 pages, 8 figures and 1 table; v5 accepted by Physics Review D; v4 add T parameter calculation detail in Appendix B; v3 updated with the EWPT bound and more detail for the model and neutrino mass loop function; v2 typo corrected and figure updated
Phys. Rev. D 101, 035006 (2020)
10.1103/PhysRevD.101.035006
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose a Two-Loop induced radiative neutrino model with hidden gauged $U(1)$ symmetry, in which a dark matter of Dirac fermion arises. The relic density gets contribution from annihilation and semi-annihilation due to a residual $\mathbb{Z}_3$ parity. After imposing the requirement of neutrino oscillation data and lepton flavour violation bounds, we find out that the semi-annihilation plays a crucial role in order to satisfy the relic density constraint $0.117 < \Omega h^2 < 0.123$, by proceeding near either one of two deconstructive scalar resonances. Our numerical analysis demonstrates the allowed region for the DM-Scalar coupling with the DM mass in $(80, 400)$ GeV.
[ { "created": "Fri, 26 Jul 2019 14:36:23 GMT", "version": "v1" }, { "created": "Thu, 1 Aug 2019 15:58:53 GMT", "version": "v2" }, { "created": "Mon, 4 Nov 2019 18:51:18 GMT", "version": "v3" }, { "created": "Wed, 6 Nov 2019 17:56:18 GMT", "version": "v4" }, { "created": "Sun, 15 Dec 2019 11:58:20 GMT", "version": "v5" } ]
2020-02-12
[ [ "Cai", "Haiying", "" ] ]
We propose a Two-Loop induced radiative neutrino model with hidden gauged $U(1)$ symmetry, in which a dark matter of Dirac fermion arises. The relic density gets contribution from annihilation and semi-annihilation due to a residual $\mathbb{Z}_3$ parity. After imposing the requirement of neutrino oscillation data and lepton flavour violation bounds, we find out that the semi-annihilation plays a crucial role in order to satisfy the relic density constraint $0.117 < \Omega h^2 < 0.123$, by proceeding near either one of two deconstructive scalar resonances. Our numerical analysis demonstrates the allowed region for the DM-Scalar coupling with the DM mass in $(80, 400)$ GeV.
1207.6227
Georg Wolschin
Felix Nendzig and Georg Wolschin
Upsilon Suppression in PbPb Collisions at sqrt(s_NN) = 2.76 TeV
4 pages, 3 figures, Proc. Hard Probes 2012 conference
null
null
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We suggest that the combined effect of screening, gluon-induced dissociation, collisional damping, and reduced feed-down explains most of the sequential suppression of Y(nS) states that has been observed in PbPb relative to pp collisions at sqrt(s_NN) = 2.76 TeV. The suppression is thus a clear, albeit indirect, indication for the presence of a qgp.
[ { "created": "Thu, 26 Jul 2012 10:26:15 GMT", "version": "v1" } ]
2012-07-27
[ [ "Nendzig", "Felix", "" ], [ "Wolschin", "Georg", "" ] ]
We suggest that the combined effect of screening, gluon-induced dissociation, collisional damping, and reduced feed-down explains most of the sequential suppression of Y(nS) states that has been observed in PbPb relative to pp collisions at sqrt(s_NN) = 2.76 TeV. The suppression is thus a clear, albeit indirect, indication for the presence of a qgp.
1203.3426
Igor Ivanov
I. P. Ivanov, V. Keus
Z_p scalar dark matter from multi-Higgs-doublet models
10 pages
null
10.1103/PhysRevD.86.016004
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In many models, stability of dark matter particles is protected by a conserved Z_2 quantum number. However dark matter can be stabilized by other discrete symmetry groups, and examples of such models with custom-tailored field content have been proposed. Here we show that electroweak symmetry breaking models with N Higgs doublets can readily accommodate scalar dark matter candidates stabilized by groups Z_p with any $p \le 2^{N-1}$, leading to a variety of kinds of microscopic dynamics in the dark sector. We give examples in which semi-annihilation or multiple semi-annihilation processes are allowed or forbidden, which can be especially interesting in the case of asymmetric dark matter.
[ { "created": "Thu, 15 Mar 2012 17:51:38 GMT", "version": "v1" } ]
2013-05-30
[ [ "Ivanov", "I. P.", "" ], [ "Keus", "V.", "" ] ]
In many models, stability of dark matter particles is protected by a conserved Z_2 quantum number. However dark matter can be stabilized by other discrete symmetry groups, and examples of such models with custom-tailored field content have been proposed. Here we show that electroweak symmetry breaking models with N Higgs doublets can readily accommodate scalar dark matter candidates stabilized by groups Z_p with any $p \le 2^{N-1}$, leading to a variety of kinds of microscopic dynamics in the dark sector. We give examples in which semi-annihilation or multiple semi-annihilation processes are allowed or forbidden, which can be especially interesting in the case of asymmetric dark matter.
1204.3665
Bartosz Dziewit
Bartosz Dziewit, Sebastian Zajac, Marek Zralek
Majorana neutrino mass matrix with CP symmetry breaking
6 pages, 2 figures, presented at the XXXV International Conference of Theoretical Physics "Matter to the Deepest 2011", Ustron, Poland, September 12-18, 2011
Acta Phys.Polon.B42:2509-2516,2011
10.5506/APhysPolB.42.2509
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
From the new existing data with not vanishing theta13 mixing angle we determine the possible shape of the Majorana neutrino mass matrix. We assume that CP symmetry is broken and all Dirac and Majorana phases are taken into account. Two possible approaches "bottom-up" and "top down" are presented. The problem of unphysical phases is examined in detail.
[ { "created": "Mon, 16 Apr 2012 22:24:55 GMT", "version": "v1" } ]
2012-04-18
[ [ "Dziewit", "Bartosz", "" ], [ "Zajac", "Sebastian", "" ], [ "Zralek", "Marek", "" ] ]
From the new existing data with not vanishing theta13 mixing angle we determine the possible shape of the Majorana neutrino mass matrix. We assume that CP symmetry is broken and all Dirac and Majorana phases are taken into account. Two possible approaches "bottom-up" and "top down" are presented. The problem of unphysical phases is examined in detail.