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hep-ph/9907431
Misha Kalmykov
J.Fleischer, M.Yu.Kalmykov
ON-SHELL2: FORM based package for the calculation of two-loop self-energy single scale Feynman diagrams occurring in the Standard Model
24 pages, elsart.sty; LaTeX, 4 eps-figures; in v4 the typos in Appendix A and C corrected
Comput.Phys.Commun.128:531-549,2000
10.1016/S0010-4655(99)00532-9
null
hep-ph
null
A FORM based package (ON-SHELL2) for the calculation of two loop self-energy diagrams with one nonzero mass in internal lines and the external momentum on the same mass shell is elaborated. The algorithm, based on recurrence relations obtained from the integration-by-parts method, allows us to reduce diagrams with arbitrary indices (powers of scalar propagators) to a set of master integrals. The SHELL2 package is used for the calculation of special types of diagrams. Analytical results for master integrals are collected.
[ { "created": "Tue, 20 Jul 1999 14:57:21 GMT", "version": "v1" }, { "created": "Tue, 5 Oct 1999 07:41:06 GMT", "version": "v2" }, { "created": "Wed, 19 Jan 2000 21:18:10 GMT", "version": "v3" }, { "created": "Sun, 14 Jan 2001 18:16:45 GMT", "version": "v4" } ]
2014-11-17
[ [ "Fleischer", "J.", "" ], [ "Kalmykov", "M. Yu.", "" ] ]
A FORM based package (ON-SHELL2) for the calculation of two loop self-energy diagrams with one nonzero mass in internal lines and the external momentum on the same mass shell is elaborated. The algorithm, based on recurrence relations obtained from the integration-by-parts method, allows us to reduce diagrams with arbitrary indices (powers of scalar propagators) to a set of master integrals. The SHELL2 package is used for the calculation of special types of diagrams. Analytical results for master integrals are collected.
hep-ph/0102269
Alberico
W.M. Alberico, S.M. Bilenky and C. Maieron
Strangeness in the nucleon: neutrino-nucleon and polarized electron-nucleon scattering
118 pages, 21 figures, to be published in Physics Reports
Phys.Rept. 358 (2002) 227-308
10.1016/S0370-1573(01)00058-8
null
hep-ph nucl-th
null
After the EMC and subsequent experiments at CERN, SLAC and DESY on the deep inelastic scattering of polarized leptons on polarized nucleons, it is now established that the Q^2=0 value of the axial strange form factor of the nucleon, a quantity which is connected with the spin of the proton and is quite relevant from the theoretical point of view, is relatively large. In this review we consider different methods and observables that allow to obtain information on the strange axial and vector form factors of the nucleon at different values of Q^2. These methods are based on the investigation of the Neutral Current induced effects such as the P-odd asymmetry in the scattering of polarized electrons on protons and nuclei, the elastic neutrino (antineutrino) scattering on protons and the quasi-elastic neutrino (antineutrino) scattering on nuclei. We discuss in details the phenomenology of these processes and the existing experimental data.
[ { "created": "Wed, 21 Feb 2001 18:35:04 GMT", "version": "v1" }, { "created": "Fri, 23 Feb 2001 10:22:05 GMT", "version": "v2" }, { "created": "Thu, 31 May 2001 12:03:41 GMT", "version": "v3" } ]
2009-11-07
[ [ "Alberico", "W. M.", "" ], [ "Bilenky", "S. M.", "" ], [ "Maieron", "C.", "" ] ]
After the EMC and subsequent experiments at CERN, SLAC and DESY on the deep inelastic scattering of polarized leptons on polarized nucleons, it is now established that the Q^2=0 value of the axial strange form factor of the nucleon, a quantity which is connected with the spin of the proton and is quite relevant from the theoretical point of view, is relatively large. In this review we consider different methods and observables that allow to obtain information on the strange axial and vector form factors of the nucleon at different values of Q^2. These methods are based on the investigation of the Neutral Current induced effects such as the P-odd asymmetry in the scattering of polarized electrons on protons and nuclei, the elastic neutrino (antineutrino) scattering on protons and the quasi-elastic neutrino (antineutrino) scattering on nuclei. We discuss in details the phenomenology of these processes and the existing experimental data.
hep-ph/0606182
Thomas Hambye
Thomas Hambye
Leptogenesis from right-handed neutrino decays to right-handed leptons
To appear in the proceedings of 41st Rencontres de Moriond on Electroweak Interactions and Unified Theories, La Thuile, Aosta Valley, Italy, 11-18 Mar 2006
null
null
null
hep-ph
null
We investigate what would be the consequences for leptogenesis of the existence of a charged SU(2)_L singlet scalar delta^+. If such a scalar particle exists, it allows the right-handed neutrinos to couple not only to left-handed lepton and Higgs doublets as in ordinary leptogenesis, but also to a right-handed charged lepton and a delta^+. This provides a new source of leptogenesis which can be successful in a non-resonant way at scales as low as TeV. The incorporation of this scenario in left-right symmetric and unified models is discussed.
[ { "created": "Fri, 16 Jun 2006 15:23:32 GMT", "version": "v1" } ]
2007-05-23
[ [ "Hambye", "Thomas", "" ] ]
We investigate what would be the consequences for leptogenesis of the existence of a charged SU(2)_L singlet scalar delta^+. If such a scalar particle exists, it allows the right-handed neutrinos to couple not only to left-handed lepton and Higgs doublets as in ordinary leptogenesis, but also to a right-handed charged lepton and a delta^+. This provides a new source of leptogenesis which can be successful in a non-resonant way at scales as low as TeV. The incorporation of this scenario in left-right symmetric and unified models is discussed.
1008.0139
Yogiro Hama
R.P.G. Andrade, F. Grassi, Y. Hama, and W.-L. Qian
Hydrodynamics: Fluctuating Initial Conditions and Two-particle Correlations
7 pages, 9 figures, presented at the Workshop on Saturation, the Color Glass Condensate and Glasma: What Have we Learned from RHIC?
Nucl.Phys.A854:81-88,2011
10.1016/j.nuclphysa.2010.08.004
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Event-by-event hydrodynamics (or hydrodynamics with fluctuating initial conditions) has been developed in the past few years. Here we discuss how it may help to understand the various structures observed in two-particle correlations.
[ { "created": "Sun, 1 Aug 2010 01:45:40 GMT", "version": "v1" } ]
2011-03-17
[ [ "Andrade", "R. P. G.", "" ], [ "Grassi", "F.", "" ], [ "Hama", "Y.", "" ], [ "Qian", "W. -L.", "" ] ]
Event-by-event hydrodynamics (or hydrodynamics with fluctuating initial conditions) has been developed in the past few years. Here we discuss how it may help to understand the various structures observed in two-particle correlations.
0801.2545
Ernest Ma
Ernest Ma (UC Riverside)
Supersymmetric U(1) Gauge Realization of the Dark Scalar Doublet Model of Radiative Neutrino Mass
8 pages, 3 figures
Mod.Phys.Lett.A23:721-725,2008
10.1142/S0217732308026753
UCRHEP-T444
hep-ph
null
Adding a second scalar doublet (eta^+,eta^0) and three neutral singlet fermions N_{1,2,3} to the Standard Model of particle interactions with a new Z_2 symmetry, it has been shown that Re(eta^0) or Im(eta^0) is a good dark-matter candidate and seesaw neutrino masses are generated radiatively. A supersymmetric U(1) gauge extension of this new idea is proposed, which enforces the usual R parity of the Minimal Supersymmetric Standard Model, and allows this new Z_2 symmetry to emerge as a discrete remnant.
[ { "created": "Wed, 16 Jan 2008 18:07:03 GMT", "version": "v1" }, { "created": "Mon, 21 Jan 2008 20:33:28 GMT", "version": "v2" } ]
2008-11-26
[ [ "Ma", "Ernest", "", "UC Riverside" ] ]
Adding a second scalar doublet (eta^+,eta^0) and three neutral singlet fermions N_{1,2,3} to the Standard Model of particle interactions with a new Z_2 symmetry, it has been shown that Re(eta^0) or Im(eta^0) is a good dark-matter candidate and seesaw neutrino masses are generated radiatively. A supersymmetric U(1) gauge extension of this new idea is proposed, which enforces the usual R parity of the Minimal Supersymmetric Standard Model, and allows this new Z_2 symmetry to emerge as a discrete remnant.
1512.09203
Xiaoyun Wang
Xiao-Yun Wang and Alexey Guskov
Charmed hadron photoproduction at COMPASS
Proceedings of the Second International Symposium on Physics of Photons (ISPP 15), Lanzhou, China, July 2016
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Photoproduction of the charmonium-like state $Z_{c}(4200)$ and the charmed baryon $\Lambda_{c}^{\ast }(2940)$ is investigated with an effective Lagrangian approach and the Regge trajectories applying to the COMPASS experiment. Combining the experimental data from COMPASS and our theoretical model we estimate the upper limit of $\Gamma_{Z_{c}(4200)\rightarrow J/\psi \pi }$ to be of about 37 MeV. Moreover, the possibility to produce $\Lambda_{c}^{\ast }(2940)$ at COMPASS is discussed. It seems one can try to search for this hadron in the missing mass spectrum since the $t$-channel is dominating for the $\Lambda_{c}^{\ast }(2940)$ photoproduction.
[ { "created": "Thu, 31 Dec 2015 03:06:27 GMT", "version": "v1" } ]
2016-01-01
[ [ "Wang", "Xiao-Yun", "" ], [ "Guskov", "Alexey", "" ] ]
Photoproduction of the charmonium-like state $Z_{c}(4200)$ and the charmed baryon $\Lambda_{c}^{\ast }(2940)$ is investigated with an effective Lagrangian approach and the Regge trajectories applying to the COMPASS experiment. Combining the experimental data from COMPASS and our theoretical model we estimate the upper limit of $\Gamma_{Z_{c}(4200)\rightarrow J/\psi \pi }$ to be of about 37 MeV. Moreover, the possibility to produce $\Lambda_{c}^{\ast }(2940)$ at COMPASS is discussed. It seems one can try to search for this hadron in the missing mass spectrum since the $t$-channel is dominating for the $\Lambda_{c}^{\ast }(2940)$ photoproduction.
hep-ph/9801301
Thomas Paul
T. Paul and Z. Was
Inclusion of tau anomalous magnetic and electric dipole moments in the KORALZ Monte Carlo
14 pages, 9 figures
null
null
L3 Note 2184
hep-ph
null
We describe modifications made to KORALZ version 4.03 in order to allow for anomalous magnetic and electric dipole moments of the tau. We discuss the verification of the method at LEP 1 energies.
[ { "created": "Wed, 14 Jan 1998 16:03:35 GMT", "version": "v1" } ]
2007-05-23
[ [ "Paul", "T.", "" ], [ "Was", "Z.", "" ] ]
We describe modifications made to KORALZ version 4.03 in order to allow for anomalous magnetic and electric dipole moments of the tau. We discuss the verification of the method at LEP 1 energies.
hep-ph/0309144
Grigory Volovik
G.E. Volovik
Coexistence of different vacua in the effective quantum field theory and Multiple Point Principle
12 pages, 1 figure, modified version submitted to JETP letters
Pisma Zh.Eksp.Teor.Fiz. 79 (2004) 131-135; JETP Lett. 79 (2004) 101-105
10.1134/1.1719122
null
hep-ph cond-mat.stat-mech gr-qc
null
According to the Multiple Point Principle our Universe is on the coexistence curve of two or more phases of the quantum vacuum. The coexistence of different quantum vacua can be regulated by the exchange of the global fermionic charges between the vacua, such as baryonic, leptonic or family charge. If the coexistence is regulated by the baryonic charge, all the coexisting vacua exhibit the baryonic asymmetry. Due to the exchange of the baryonic charge between the vacuum and matter which occurs above the electroweak transition, the baryonic asymmetry of the vacuum induces the baryonic asymmetry of matter in our Standard-Model phase of the quantum vacuum. The present baryonic asymmetry of the Universe indicates that the characteristic energy scale which regulates the equilibrium coexistence of different phases of quantum vacua is about 10^6 GeV.
[ { "created": "Fri, 12 Sep 2003 15:30:24 GMT", "version": "v1" }, { "created": "Mon, 20 Oct 2003 08:00:45 GMT", "version": "v2" }, { "created": "Thu, 23 Oct 2003 15:09:29 GMT", "version": "v3" }, { "created": "Mon, 5 Jan 2004 14:35:25 GMT", "version": "v4" } ]
2009-11-10
[ [ "Volovik", "G. E.", "" ] ]
According to the Multiple Point Principle our Universe is on the coexistence curve of two or more phases of the quantum vacuum. The coexistence of different quantum vacua can be regulated by the exchange of the global fermionic charges between the vacua, such as baryonic, leptonic or family charge. If the coexistence is regulated by the baryonic charge, all the coexisting vacua exhibit the baryonic asymmetry. Due to the exchange of the baryonic charge between the vacuum and matter which occurs above the electroweak transition, the baryonic asymmetry of the vacuum induces the baryonic asymmetry of matter in our Standard-Model phase of the quantum vacuum. The present baryonic asymmetry of the Universe indicates that the characteristic energy scale which regulates the equilibrium coexistence of different phases of quantum vacua is about 10^6 GeV.
1607.00374
Kasper Lang{\ae}ble
Chris Kouvaris, Kasper Langaeble, Niklas Gr{\o}nlund Nielsen
The Spectrum of Darkonium in the Sun
24 pages, 7 figures
null
10.1088/1475-7516/2016/10/012
CP3-Origins-2016-029 DNRF90
hep-ph astro-ph.HE astro-ph.SR
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Dark matter that gets captured in the Sun may form positronium-like bound states if it self-interacts via light dark photons. In this case, dark matter can either annihilate to dark photons or recombine in bound states which subsequently also decay to dark photons. The fraction of the dark photons that leave the Sun without decaying to Standard Model particles have a characteristic energy spectrum which is a mixture of the direct annihilation process, the decays of ortho- and para- bound states and the recombination process. The ultimate decay of these dark photons to positron-electron pairs (via kinetic mixing) outside the Sun creates a distinct signal that can either identify or set strict constraints on dark photon models.
[ { "created": "Fri, 1 Jul 2016 19:58:04 GMT", "version": "v1" } ]
2016-10-19
[ [ "Kouvaris", "Chris", "" ], [ "Langaeble", "Kasper", "" ], [ "Nielsen", "Niklas Grønlund", "" ] ]
Dark matter that gets captured in the Sun may form positronium-like bound states if it self-interacts via light dark photons. In this case, dark matter can either annihilate to dark photons or recombine in bound states which subsequently also decay to dark photons. The fraction of the dark photons that leave the Sun without decaying to Standard Model particles have a characteristic energy spectrum which is a mixture of the direct annihilation process, the decays of ortho- and para- bound states and the recombination process. The ultimate decay of these dark photons to positron-electron pairs (via kinetic mixing) outside the Sun creates a distinct signal that can either identify or set strict constraints on dark photon models.
2012.09094
Seyed Mohsen Hosseini Nejad
Seyed Mohsen Hosseini Nejad
Contributions of the Cartan generators in potentials between static sources
10 pages, 8 figures, accepted for publication in International Journal of Modern Physics A
null
null
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
We investigate the contributions of the Cartan generators in the static potentials for various representations in the framework of the domain model of center vortices for SU(3) gauge theory. Using the center domains with the cores corresponding to only one Cartan generator H8, already given as a particular proposal, leads to some concavities in the potentials for higher representations. Furthermore, the string tension of the fundamental representation is the same at Casimir scaling and N-ality regimes. We add the contribution of the other Cartan generator H3 to the potentials and therefore these shortcomings can be eliminated. However, we discuss that at intermediate range of distances the potentials induced by only H8 agree with the Casimir scaling better than those corresponding to both Cartan generators.
[ { "created": "Wed, 16 Dec 2020 17:31:01 GMT", "version": "v1" } ]
2020-12-17
[ [ "Nejad", "Seyed Mohsen Hosseini", "" ] ]
We investigate the contributions of the Cartan generators in the static potentials for various representations in the framework of the domain model of center vortices for SU(3) gauge theory. Using the center domains with the cores corresponding to only one Cartan generator H8, already given as a particular proposal, leads to some concavities in the potentials for higher representations. Furthermore, the string tension of the fundamental representation is the same at Casimir scaling and N-ality regimes. We add the contribution of the other Cartan generator H3 to the potentials and therefore these shortcomings can be eliminated. However, we discuss that at intermediate range of distances the potentials induced by only H8 agree with the Casimir scaling better than those corresponding to both Cartan generators.
1802.01559
Vitaly Okorokov A
V. A. Petrov (A.A. Logunov Institute for High Energy Physics, NRC KI), V. A. Okorokov (National Research Nuclear University MEPhI)
The Size Seems to Matter or Where Lies the "Asymptopia"?
30 pages, 7 figures and 3 tables
Int. J. Mod. Phys. A33, 1850077 (2018)
10.1142/S0217751X1850077X
null
hep-ph hep-ex hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We discuss an apparent correlation between the onset of the rising regime for the total cross-sections and the slowdown of the rise of the forward slopes with energy. It is shown that even at highest energies achieved with the LHC the proper sizes of the colliding protons comprise the bulk of the the interaction region. This seems to witness that the "asymptopia" - a hypothetical "truly asymptotic" regime - lies at energies no less than $\mathcal{O}$(100 TeV). In the course of reasoning we also discuss the question of the dependence of the effective sizes of hadrons in collision on the type of their interaction.
[ { "created": "Mon, 5 Feb 2018 18:45:45 GMT", "version": "v1" }, { "created": "Mon, 12 Feb 2018 09:17:57 GMT", "version": "v2" }, { "created": "Fri, 11 May 2018 07:11:57 GMT", "version": "v3" } ]
2018-05-15
[ [ "Petrov", "V. A.", "", "A.A. Logunov Institute for High Energy Physics, NRC KI" ], [ "Okorokov", "V. A.", "", "National Research Nuclear University MEPhI" ] ]
We discuss an apparent correlation between the onset of the rising regime for the total cross-sections and the slowdown of the rise of the forward slopes with energy. It is shown that even at highest energies achieved with the LHC the proper sizes of the colliding protons comprise the bulk of the the interaction region. This seems to witness that the "asymptopia" - a hypothetical "truly asymptotic" regime - lies at energies no less than $\mathcal{O}$(100 TeV). In the course of reasoning we also discuss the question of the dependence of the effective sizes of hadrons in collision on the type of their interaction.
1906.02218
S. Weinzierl
Robert Runkel, Zolt\'an Sz\H{o}r, Juan Pablo Vesga and Stefan Weinzierl
Integrands of loop amplitudes within loop-tree duality
45 pages, v2: combinatorial factors included, v3: version to be published
Phys. Rev. D 101, 116014 (2020)
10.1103/PhysRevD.101.116014
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Using loop-tree duality, we relate a renormalised $n$-point $l$-loop amplitude in a quantum field theory to a phase-space integral of a regularised $l$-fold forward limit of a UV-subtracted $(n+2l)$-point tree-amplitude-like object. We show that up to three loops the latter object is easily computable from recurrence relations. This defines an integrand of the loop amplitude with a global definition of the loop momenta. Field and mass renormalisation are performed in the on-shell scheme.
[ { "created": "Wed, 5 Jun 2019 18:02:14 GMT", "version": "v1" }, { "created": "Thu, 15 Aug 2019 13:09:14 GMT", "version": "v2" }, { "created": "Thu, 4 Jun 2020 14:21:34 GMT", "version": "v3" } ]
2020-07-01
[ [ "Runkel", "Robert", "" ], [ "Szőr", "Zoltán", "" ], [ "Vesga", "Juan Pablo", "" ], [ "Weinzierl", "Stefan", "" ] ]
Using loop-tree duality, we relate a renormalised $n$-point $l$-loop amplitude in a quantum field theory to a phase-space integral of a regularised $l$-fold forward limit of a UV-subtracted $(n+2l)$-point tree-amplitude-like object. We show that up to three loops the latter object is easily computable from recurrence relations. This defines an integrand of the loop amplitude with a global definition of the loop momenta. Field and mass renormalisation are performed in the on-shell scheme.
2402.00741
Minho Son
Heejoo Kim, Junghyeon Park, Minho Son
Axion Dark Matter from Cosmic String Network
60 pages, 29 figures, typos corrected, references added, version accepted for publication in JHEP
null
null
null
hep-ph astro-ph.CO
http://creativecommons.org/licenses/by/4.0/
We perform the lattice simulation to estimate the axion dark matter abundance radiated from the global cosmic strings in the post-inflationary scenario. The independent numerical confirmation on the recently observed logarithmic growth in both the number of strings per Hubble patch and the spectral index of the power law scaling for the axion spectrum is reported. These logarithmic scalings are checked against two different prescriptions for generating initial random field configurations, namely fat-string type and thermal phase transition. We discuss a possible strong correlation between the axion spectrum and the string evolutions with different initial conditions to support the insensitivity of scaling behaviors against different initial data and we provide a qualitative understanding of it. The impact of various combinations of the power law of the axion spectrum, nonlinearities around the QCD scale, and average inter-string distances on the axion abundance is discussed. Additionally, we introduce a new novel string identification method, based on the tetrahedralization of the space, which guarantees the connectedness of the strings and provides a convenient way of assigning the core location. Finally we derive the lower bound on the axion mass.
[ { "created": "Thu, 1 Feb 2024 16:39:18 GMT", "version": "v1" }, { "created": "Thu, 8 Feb 2024 08:00:39 GMT", "version": "v2" }, { "created": "Tue, 16 Jul 2024 10:36:58 GMT", "version": "v3" } ]
2024-07-17
[ [ "Kim", "Heejoo", "" ], [ "Park", "Junghyeon", "" ], [ "Son", "Minho", "" ] ]
We perform the lattice simulation to estimate the axion dark matter abundance radiated from the global cosmic strings in the post-inflationary scenario. The independent numerical confirmation on the recently observed logarithmic growth in both the number of strings per Hubble patch and the spectral index of the power law scaling for the axion spectrum is reported. These logarithmic scalings are checked against two different prescriptions for generating initial random field configurations, namely fat-string type and thermal phase transition. We discuss a possible strong correlation between the axion spectrum and the string evolutions with different initial conditions to support the insensitivity of scaling behaviors against different initial data and we provide a qualitative understanding of it. The impact of various combinations of the power law of the axion spectrum, nonlinearities around the QCD scale, and average inter-string distances on the axion abundance is discussed. Additionally, we introduce a new novel string identification method, based on the tetrahedralization of the space, which guarantees the connectedness of the strings and provides a convenient way of assigning the core location. Finally we derive the lower bound on the axion mass.
1804.03662
Benjamin Lillard
Benjamin Lillard, Michael Ratz, Tim M.P. Tait, Sebastian Trojanowski
The Flavor of Cosmology
26 pages, 5 figures, 5 appendices
null
10.1088/1475-7516/2018/07/056
UCI-TR-2018-04
hep-ph astro-ph.CO hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We discuss the cosmology of models in which the standard model Yukawa couplings depend on scalar field(s), often referred to as flavons. We find that thermal corrections of the flavon potential tend to decrease the Yukawa couplings, providing an important input to model-building. Working in the specific framework of Froggatt-Nielsen models, we compute the abundance of flavons in the early universe generated both via freeze-in and from coherent oscillations induced by thermal corrections to their potential, and discuss constraints on flavon models from cosmology. We find that cosmology places important constraints on theories containing flavons even for regions of parameter space inaccessible to collider searches.
[ { "created": "Tue, 10 Apr 2018 18:00:04 GMT", "version": "v1" } ]
2018-08-08
[ [ "Lillard", "Benjamin", "" ], [ "Ratz", "Michael", "" ], [ "Tait", "Tim M. P.", "" ], [ "Trojanowski", "Sebastian", "" ] ]
We discuss the cosmology of models in which the standard model Yukawa couplings depend on scalar field(s), often referred to as flavons. We find that thermal corrections of the flavon potential tend to decrease the Yukawa couplings, providing an important input to model-building. Working in the specific framework of Froggatt-Nielsen models, we compute the abundance of flavons in the early universe generated both via freeze-in and from coherent oscillations induced by thermal corrections to their potential, and discuss constraints on flavon models from cosmology. We find that cosmology places important constraints on theories containing flavons even for regions of parameter space inaccessible to collider searches.
hep-ph/9410311
David Garcia Muchart. Tn:
D. Garcia, R. A. Jimenez and J. Sola
Supersymmetric Electroweak Renormaliztion of the Z-Width in the MSSM (II)
16 p. in LaTeX. Preprint UAB-FT-344. Error in the labelling of fig.3 corrected. Results unchanged
Phys.Lett. B347 (1995) 321-331; Erratum-ibid. B351 (1995) 602
10.1016/0370-2693(94)00407-X
null
hep-ph
null
We address the computation of \Gamma_Z and of the intriguing quantity R_b in the MSSM including full treatment of the Higgs sector. For a pseudoscalar Higgs mass m_{A^0}>70\,GeV and CDF limits on m_t, the bounds on R_b at 1\sigma level leave no room to the MSSM to solve the `R_b crisis' for any combination of the parameters, not even admitting the possibility of a light chargino and a light stop of O(50) GeV; however, for m_t not restricted by CDF, a `tangential' solution exists in the window 2<\tan\beta<10 with a light chargino and stop. In contrast, for a pseudoscalar mass 40\,GeV<m_{A^0}<60\,GeV and CDF limits on m_t, the `R_b crisis' can be solved in a comfortable way, for any SUSY spectrum above the phenomenological bounds, provided \tan\beta>m_t/m_b. Our general conclusion is that, if there is a `R_b crisis' at all, its solution within the MSSM has to do more with the peculiar structure of the SUSY Higgs sector rather than with the spectrum of genuine supersymmetric particles. In view of the range predicted for m_{A^0}, LEP 200 should be able to definitely settle down this question.
[ { "created": "Tue, 18 Oct 1994 18:06:28 GMT", "version": "v1" }, { "created": "Wed, 19 Oct 1994 10:02:45 GMT", "version": "v2" }, { "created": "Thu, 20 Oct 1994 12:23:08 GMT", "version": "v3" }, { "created": "Mon, 24 Oct 1994 17:33:09 GMT", "version": "v4" }, { "created": "Tue, 25 Oct 1994 12:50:41 GMT", "version": "v5" } ]
2009-10-28
[ [ "Garcia", "D.", "" ], [ "Jimenez", "R. A.", "" ], [ "Sola", "J.", "" ] ]
We address the computation of \Gamma_Z and of the intriguing quantity R_b in the MSSM including full treatment of the Higgs sector. For a pseudoscalar Higgs mass m_{A^0}>70\,GeV and CDF limits on m_t, the bounds on R_b at 1\sigma level leave no room to the MSSM to solve the `R_b crisis' for any combination of the parameters, not even admitting the possibility of a light chargino and a light stop of O(50) GeV; however, for m_t not restricted by CDF, a `tangential' solution exists in the window 2<\tan\beta<10 with a light chargino and stop. In contrast, for a pseudoscalar mass 40\,GeV<m_{A^0}<60\,GeV and CDF limits on m_t, the `R_b crisis' can be solved in a comfortable way, for any SUSY spectrum above the phenomenological bounds, provided \tan\beta>m_t/m_b. Our general conclusion is that, if there is a `R_b crisis' at all, its solution within the MSSM has to do more with the peculiar structure of the SUSY Higgs sector rather than with the spectrum of genuine supersymmetric particles. In view of the range predicted for m_{A^0}, LEP 200 should be able to definitely settle down this question.
2210.13213
Dhananjay Saikumar Mr
Dhananjay Saikumar
Future of computing at the Large Hadron Collider
null
null
null
null
hep-ph hep-ex
http://creativecommons.org/licenses/by/4.0/
High energy physics (HEP) experiments at the LHC generate data at a rate of $\mathcal{O}(10)$ Terabits per second. This data rate is expected to exponentially increase as experiments will be upgraded in the future to achieve higher collision energies. The increasing size of particle physics datasets combined with the plateauing single-core CPU performance is expected to create a four-fold shortage in computing power by 2030. This makes it necessary to investigate alternate computing architectures to cope with the next generation of HEP experiments. This study provides an overview of different computing techniques used in the LHCb experiment (trigger, track reconstruction, vertex reconstruction, particle identification). Furthermore, this research led to the creation of three event reconstruction algorithms for the LHCb experiment. These algorithms are benchmarked on various computing architectures such as the CPU, GPU, and a new type of processor called the IPU, each roughly containing $\mathcal{O}(10)$, $\mathcal{O}(1000)$, and $\mathcal{O}(1000)$ cores respectively. This research indicates that multi-core architectures such as GPUs and IPUs are better suited for computationally intensive tasks within HEP experiments.
[ { "created": "Tue, 27 Sep 2022 13:13:09 GMT", "version": "v1" } ]
2022-10-25
[ [ "Saikumar", "Dhananjay", "" ] ]
High energy physics (HEP) experiments at the LHC generate data at a rate of $\mathcal{O}(10)$ Terabits per second. This data rate is expected to exponentially increase as experiments will be upgraded in the future to achieve higher collision energies. The increasing size of particle physics datasets combined with the plateauing single-core CPU performance is expected to create a four-fold shortage in computing power by 2030. This makes it necessary to investigate alternate computing architectures to cope with the next generation of HEP experiments. This study provides an overview of different computing techniques used in the LHCb experiment (trigger, track reconstruction, vertex reconstruction, particle identification). Furthermore, this research led to the creation of three event reconstruction algorithms for the LHCb experiment. These algorithms are benchmarked on various computing architectures such as the CPU, GPU, and a new type of processor called the IPU, each roughly containing $\mathcal{O}(10)$, $\mathcal{O}(1000)$, and $\mathcal{O}(1000)$ cores respectively. This research indicates that multi-core architectures such as GPUs and IPUs are better suited for computationally intensive tasks within HEP experiments.
2006.11243
Lennert J. Thormaehlen
Gonzalo Alonso-\'Alvarez, Fatih Ertas, Joerg Jaeckel, Felix Kahlhoefer and Lennert J. Thormaehlen
Hidden Photon Dark Matter in the Light of XENON1T and Stellar Cooling
15 pages, 2 figures, improved statistical analysis
null
10.1088/1475-7516/2020/11/029
TTK-20-19
hep-ph astro-ph.CO hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The low-energy electronic recoil spectrum in XENON1T provides an intriguing hint for potential new physics. At the same time, observations of horizontal branch stars favor the existence of a small amount of extra cooling compared to the one expected from the Standard Model particle content. In this note, we argue that a hidden photon with a mass of $\sim 2.5$ keV and a kinetic mixing of $\sim 10^{-15}$ allows for a good fit to both of these excesses. In this scenario, the signal detected in XENON1T is due to the absorption of hidden photon dark matter particles, whereas the anomalous cooling of horizontal branch stars arises from resonant production of hidden photons in the stellar interior.
[ { "created": "Fri, 19 Jun 2020 17:29:31 GMT", "version": "v1" }, { "created": "Mon, 13 Jul 2020 16:19:02 GMT", "version": "v2" }, { "created": "Fri, 18 Sep 2020 10:30:51 GMT", "version": "v3" } ]
2020-11-25
[ [ "Alonso-Álvarez", "Gonzalo", "" ], [ "Ertas", "Fatih", "" ], [ "Jaeckel", "Joerg", "" ], [ "Kahlhoefer", "Felix", "" ], [ "Thormaehlen", "Lennert J.", "" ] ]
The low-energy electronic recoil spectrum in XENON1T provides an intriguing hint for potential new physics. At the same time, observations of horizontal branch stars favor the existence of a small amount of extra cooling compared to the one expected from the Standard Model particle content. In this note, we argue that a hidden photon with a mass of $\sim 2.5$ keV and a kinetic mixing of $\sim 10^{-15}$ allows for a good fit to both of these excesses. In this scenario, the signal detected in XENON1T is due to the absorption of hidden photon dark matter particles, whereas the anomalous cooling of horizontal branch stars arises from resonant production of hidden photons in the stellar interior.
hep-ph/9806518
Valerie Nowak
Stephen L. Adler
Model for Particle Masses, Flavor Mixing, and CP Violation Based on Spontaneously Broken Discrete Chiral Symmetry as the Origin of Families
Revtex, 59 pages including four tables at end
Phys.Rev.D59:015012,1999; Erratum-ibid.D59:099902,1999
10.1103/PhysRevD.59.015012 10.1103/PhysRevD.59.099902
IASSNS-HEP -98/46
hep-ph
null
We construct extensions of the standard model based on the hypothesis that the Higgs bosons also exhibit a family structure, and that the flavor weak eigenstates in the three families are distinguished by a discrete $Z_6$ chiral symmetry that is spontaneously broken by the Higgs sector. We study in detail at the tree level models with three Higgs doublets, and with six Higgs doublets comprising two weakly coupled sets of three. In a leading approximation of $S_3$ cyclic permutation symmetry the three Higgs model gives a ``democratic'' mass matrix of rank one, while the six Higgs model gives either a rank one mass matrix, or in the case when it spontaneously violates CP, a rank two mass matrix corresponding to nonzero second family masses. In both models, the CKM matrix is exactly unity in leading approximation. Allowing small explicit violations of cyclic permutation symmetry generates small first family masses in the six Higgs model, and first and second family masses in the three Higgs model, and gives a non-trivial CKM matrix in which the mixings of the first and second family quarks are naturally larger than mixings involving the third family. Complete numerical fits are given for both models, flavor changing neutral current constraints are discussed in detail, and the issues of unification of couplings and neutrino masses are addressed. On a technical level, our analysis uses the theory of circulant and retrocirculant matrices, the relevant parts of which are reviewed.
[ { "created": "Mon, 29 Jun 1998 14:52:59 GMT", "version": "v1" }, { "created": "Fri, 11 Sep 1998 20:58:07 GMT", "version": "v2" } ]
2014-11-17
[ [ "Adler", "Stephen L.", "" ] ]
We construct extensions of the standard model based on the hypothesis that the Higgs bosons also exhibit a family structure, and that the flavor weak eigenstates in the three families are distinguished by a discrete $Z_6$ chiral symmetry that is spontaneously broken by the Higgs sector. We study in detail at the tree level models with three Higgs doublets, and with six Higgs doublets comprising two weakly coupled sets of three. In a leading approximation of $S_3$ cyclic permutation symmetry the three Higgs model gives a ``democratic'' mass matrix of rank one, while the six Higgs model gives either a rank one mass matrix, or in the case when it spontaneously violates CP, a rank two mass matrix corresponding to nonzero second family masses. In both models, the CKM matrix is exactly unity in leading approximation. Allowing small explicit violations of cyclic permutation symmetry generates small first family masses in the six Higgs model, and first and second family masses in the three Higgs model, and gives a non-trivial CKM matrix in which the mixings of the first and second family quarks are naturally larger than mixings involving the third family. Complete numerical fits are given for both models, flavor changing neutral current constraints are discussed in detail, and the issues of unification of couplings and neutrino masses are addressed. On a technical level, our analysis uses the theory of circulant and retrocirculant matrices, the relevant parts of which are reviewed.
1611.09147
Luca Zambelli
Holger Gies and Luca Zambelli
Nonabelian Higgs models: paving the way for asymptotic freedom
39 pages, 32 figures
Phys. Rev. D 96, 025003 (2017)
10.1103/PhysRevD.96.025003
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Asymptotically free renormalization group trajectories can be constructed in nonabelian Higgs models with the aid of generalized boundary conditions imposed on the renormalized action. We detail this construction within the languages of simple low-order perturbation theory, effective field theory, as well as modern functional renormalization group equations. We construct a family of explicit scaling solutions using a controlled weak-coupling expansion in the ultraviolet, and obtain a standard Wilsonian RG relevance classification of perturbations about scaling solutions. We obtain global information about the quasi-fixed function for the scalar potential by means of analytic asymptotic expansions and numerical shooting methods. Further analytical evidence for such asymptotically free theories is provided in the large-N limit. We estimate the long-range properties of these theories, and identify initial/boundary conditions giving rise to a conventional Higgs phase.
[ { "created": "Mon, 28 Nov 2016 14:51:16 GMT", "version": "v1" } ]
2017-07-19
[ [ "Gies", "Holger", "" ], [ "Zambelli", "Luca", "" ] ]
Asymptotically free renormalization group trajectories can be constructed in nonabelian Higgs models with the aid of generalized boundary conditions imposed on the renormalized action. We detail this construction within the languages of simple low-order perturbation theory, effective field theory, as well as modern functional renormalization group equations. We construct a family of explicit scaling solutions using a controlled weak-coupling expansion in the ultraviolet, and obtain a standard Wilsonian RG relevance classification of perturbations about scaling solutions. We obtain global information about the quasi-fixed function for the scalar potential by means of analytic asymptotic expansions and numerical shooting methods. Further analytical evidence for such asymptotically free theories is provided in the large-N limit. We estimate the long-range properties of these theories, and identify initial/boundary conditions giving rise to a conventional Higgs phase.
1001.0022
Ian Lewis
Tao Han, Ian Lewis and Marc Sher
Mu-Tau Production at Hadron Colliders
16 pages, 9 figures
JHEP 1003:090,2010
10.1007/JHEP03(2010)090
MADPH-09-1552
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Motivated by large nu_mu-nu_tau flavor mixing, we consider mu-tau production at hadron colliders via dimension-6 effective operators, which can be attributed to new physics in the flavor sector at a higher scale Lambda. Current bounds on many of these operators from low energy experiments are very weak or nonexistent, and they may lead to clean mu+tau- and mu-tau+ signals at hadron colliders. At the Tevatron with 8 inverse femtobarns, one can exceed current bounds for most operators, with most 2 sigma sensitivities being in the 6-24 TeV range. We find that at the LHC with 1 (100) inverse femtobarns integrated luminosity, one can reach a 2 sigma sensitivity for Lambda \sim 3-10 TeV (Lambda =\sim 6-21 TeV), depending on the Lorentz structure of the operator. For some operators, an improvement of several orders of magnitude in sensitivity can be obtained with only a few tens of inverse picobarns at the LHC.
[ { "created": "Mon, 4 Jan 2010 04:10:52 GMT", "version": "v1" }, { "created": "Wed, 17 Mar 2010 21:47:07 GMT", "version": "v2" } ]
2010-04-30
[ [ "Han", "Tao", "" ], [ "Lewis", "Ian", "" ], [ "Sher", "Marc", "" ] ]
Motivated by large nu_mu-nu_tau flavor mixing, we consider mu-tau production at hadron colliders via dimension-6 effective operators, which can be attributed to new physics in the flavor sector at a higher scale Lambda. Current bounds on many of these operators from low energy experiments are very weak or nonexistent, and they may lead to clean mu+tau- and mu-tau+ signals at hadron colliders. At the Tevatron with 8 inverse femtobarns, one can exceed current bounds for most operators, with most 2 sigma sensitivities being in the 6-24 TeV range. We find that at the LHC with 1 (100) inverse femtobarns integrated luminosity, one can reach a 2 sigma sensitivity for Lambda \sim 3-10 TeV (Lambda =\sim 6-21 TeV), depending on the Lorentz structure of the operator. For some operators, an improvement of several orders of magnitude in sensitivity can be obtained with only a few tens of inverse picobarns at the LHC.
2003.08321
Wojciech Bizon
Arnd Behring, Wojciech Bizon, Fabrizio Caola, Kirill Melnikov, Raoul R\"ontsch
Bottom quark mass effects in associated $WH$ production with $H \to b\bar{b}$ decay through NNLO QCD
30 pages, 9 figures
Phys. Rev. D 101, 114012 (2020)
10.1103/PhysRevD.101.114012
TTP20-011, P3H-20-009, CERN-TH-2020-043
hep-ph
http://creativecommons.org/licenses/by-sa/4.0/
We present a computation of NNLO QCD corrections to the production of a Higgs boson in association with a $W$ boson at the LHC followed by the decay of the Higgs boson to a $b\bar{b}$ pair. At variance with previous NNLO QCD studies of the same process, we treat $b$ quarks as massive. An important advantage of working with massive $b$ quarks is that it makes the use of flavor jet algorithms unnecessary and allows us to employ conventional jet algorithms to define $b$ jets. We compare NNLO QCD descriptions of the associated $WH(b\bar{b})$ production with massive and massless $b$ quarks and also contrast them with the results provided by parton showers. We find ${\cal O}(5\%)$ differences in fiducial cross sections computed with massless and massive $b$ quarks. We also observe that much larger differences between massless and massive results, as well as between fixed-order and parton-shower results, can arise in selected kinematic distributions.
[ { "created": "Wed, 18 Mar 2020 16:25:49 GMT", "version": "v1" } ]
2020-07-01
[ [ "Behring", "Arnd", "" ], [ "Bizon", "Wojciech", "" ], [ "Caola", "Fabrizio", "" ], [ "Melnikov", "Kirill", "" ], [ "Röntsch", "Raoul", "" ] ]
We present a computation of NNLO QCD corrections to the production of a Higgs boson in association with a $W$ boson at the LHC followed by the decay of the Higgs boson to a $b\bar{b}$ pair. At variance with previous NNLO QCD studies of the same process, we treat $b$ quarks as massive. An important advantage of working with massive $b$ quarks is that it makes the use of flavor jet algorithms unnecessary and allows us to employ conventional jet algorithms to define $b$ jets. We compare NNLO QCD descriptions of the associated $WH(b\bar{b})$ production with massive and massless $b$ quarks and also contrast them with the results provided by parton showers. We find ${\cal O}(5\%)$ differences in fiducial cross sections computed with massless and massive $b$ quarks. We also observe that much larger differences between massless and massive results, as well as between fixed-order and parton-shower results, can arise in selected kinematic distributions.
1612.00660
Alexander Bednyakov
A.V. Bednyakov, B.A. Kniehl, A.F. Pikelner, O.L. Veretin
On the $b$-quark running mass in QCD and the SM
19 pages, 4 figures, misprints corrected (thanks to S. Martin), results not affected
Nucl.Phys. B916 (2017) 463-483
10.1016/j.nuclphysb.2017.01.004
DESY 16-234
hep-ph
http://creativecommons.org/licenses/by/4.0/
We consider electroweak corrections to the relation between the running $\overline{\mathrm{MS}}$ mass $m_b$ of the $b$ quark in the five-flavor QCD$\times$QED effective theory and its counterpart in the Standard Model (SM). As a bridge between the two parameters, we use the pole mass $M_b$ of the $b$ quark, which can be calculated in both models. The running mass is not a fundamental parameter of the SM Lagrangian, but the product of the running Yukawa coupling $y_b$ and the Higgs vacuum expectation value. Since there exist different prescriptions to define the latter, the relations considered in the paper involve a certain amount of freedom. All the definitions can be related to each other in perturbation theory. Nevertheless, we argue in favor of a certain gauge-independent prescription and provide a relation which can be directly used to deduce the value of the Yukawa coupling of the $b$ quark at the electroweak scale from its effective QCD running mass. This approach allows one to resum large logarithms $\ln(m_b/M_t)$ systematically. Numerical analysis shows that, indeed, the corrections to the proposed relation are much smaller than those between $y_b$ and $M_b$.
[ { "created": "Fri, 2 Dec 2016 12:38:08 GMT", "version": "v1" }, { "created": "Tue, 7 Mar 2017 20:22:31 GMT", "version": "v2" }, { "created": "Tue, 25 Sep 2018 08:15:03 GMT", "version": "v3" } ]
2018-09-26
[ [ "Bednyakov", "A. V.", "" ], [ "Kniehl", "B. A.", "" ], [ "Pikelner", "A. F.", "" ], [ "Veretin", "O. L.", "" ] ]
We consider electroweak corrections to the relation between the running $\overline{\mathrm{MS}}$ mass $m_b$ of the $b$ quark in the five-flavor QCD$\times$QED effective theory and its counterpart in the Standard Model (SM). As a bridge between the two parameters, we use the pole mass $M_b$ of the $b$ quark, which can be calculated in both models. The running mass is not a fundamental parameter of the SM Lagrangian, but the product of the running Yukawa coupling $y_b$ and the Higgs vacuum expectation value. Since there exist different prescriptions to define the latter, the relations considered in the paper involve a certain amount of freedom. All the definitions can be related to each other in perturbation theory. Nevertheless, we argue in favor of a certain gauge-independent prescription and provide a relation which can be directly used to deduce the value of the Yukawa coupling of the $b$ quark at the electroweak scale from its effective QCD running mass. This approach allows one to resum large logarithms $\ln(m_b/M_t)$ systematically. Numerical analysis shows that, indeed, the corrections to the proposed relation are much smaller than those between $y_b$ and $M_b$.
hep-ph/0507298
Chun Liu
Chun Liu
Supersymmetry for Fermion Masses
25 pages, 3 figures, revtex4; neutrino oscillation and many discussions added, smallness of the electron mass due to supersymmetry pointed out; v3: numerical errors corrected
Commun.Theor.Phys.47:1088-1098,2007
10.1088/0253-6102/47/6/025
null
hep-ph hep-th
null
It is proposed that supersymmetry (SUSY) maybe used to understand fermion mass hierarchies. A family symmetry Z_{3L} is introduced, which is the cyclic symmetry among the three generation SU(2) doublets. SUSY breaks at a high energy scale ~ 10^{11} GeV. The electroweak energy scale ~ 100 GeV is unnaturally small. No additional global symmetry, like the R-parity, is imposed. The Yukawa couplings and R-parity violating couplings all take their natural values which are about (10^0-10^{-2}). Under the family symmetry, only the third generation charged fermions get their masses. This family symmetry is broken in the soft SUSY breaking terms which result in a hierarchical pattern of the fermion masses. It turns out that for the charged leptons, the tau mass is from the Higgs vacuum expectation value (VEV) and the sneutrino VEVs, the muon mass is due to the sneutrino VEVs, and the electron gains its mass due to both Z_{3L} and SUSY breaking. The large neutrino mixing are produced with neutralinos playing the partial role of right-handed neutrinos. |V_{e3}| which is for nu_e-nu_{tau} mixing is expected to be about 0.1. For the quarks, the third generation masses are from the Higgs VEVs, the second generation masses are from quantum corrections, and the down quark mass due to the sneutrino VEVs. It explains m_c/m_s, m_s/m_e, m_d > m_u and so on. Other aspects of the model are discussed.
[ { "created": "Tue, 26 Jul 2005 14:36:23 GMT", "version": "v1" }, { "created": "Tue, 12 Dec 2006 14:23:06 GMT", "version": "v2" }, { "created": "Fri, 13 Apr 2007 16:57:26 GMT", "version": "v3" } ]
2014-11-18
[ [ "Liu", "Chun", "" ] ]
It is proposed that supersymmetry (SUSY) maybe used to understand fermion mass hierarchies. A family symmetry Z_{3L} is introduced, which is the cyclic symmetry among the three generation SU(2) doublets. SUSY breaks at a high energy scale ~ 10^{11} GeV. The electroweak energy scale ~ 100 GeV is unnaturally small. No additional global symmetry, like the R-parity, is imposed. The Yukawa couplings and R-parity violating couplings all take their natural values which are about (10^0-10^{-2}). Under the family symmetry, only the third generation charged fermions get their masses. This family symmetry is broken in the soft SUSY breaking terms which result in a hierarchical pattern of the fermion masses. It turns out that for the charged leptons, the tau mass is from the Higgs vacuum expectation value (VEV) and the sneutrino VEVs, the muon mass is due to the sneutrino VEVs, and the electron gains its mass due to both Z_{3L} and SUSY breaking. The large neutrino mixing are produced with neutralinos playing the partial role of right-handed neutrinos. |V_{e3}| which is for nu_e-nu_{tau} mixing is expected to be about 0.1. For the quarks, the third generation masses are from the Higgs VEVs, the second generation masses are from quantum corrections, and the down quark mass due to the sneutrino VEVs. It explains m_c/m_s, m_s/m_e, m_d > m_u and so on. Other aspects of the model are discussed.
2407.03810
Mikolaj Misiak
Mateusz Czaja and Mikolaj Misiak
Current Status of the Standard Model Prediction for the B_s -> mu^+ mu^- Branching Ratio
20 pages, 5 figures. Contribution to the "Symmetry" Special Issue "Symmetries and Anomalies in Flavour Physics"
null
null
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
The rare decay B_s -> mu^+ mu^- provides an important constraint on possible deviations from the Standard Model in b-s-l-l interactions. The present weighted average of its branching ratio measurements amounts to (3.34 \pm 0.27) x 10^-9, which remains in good agreement with the theoretical prediction of (3.64 \pm 0.12) x 10^-9 within the Standard Model. In the present paper, we review calculations that have contributed to this prediction, and discuss the associated uncertainties.
[ { "created": "Thu, 4 Jul 2024 10:33:17 GMT", "version": "v1" } ]
2024-07-08
[ [ "Czaja", "Mateusz", "" ], [ "Misiak", "Mikolaj", "" ] ]
The rare decay B_s -> mu^+ mu^- provides an important constraint on possible deviations from the Standard Model in b-s-l-l interactions. The present weighted average of its branching ratio measurements amounts to (3.34 \pm 0.27) x 10^-9, which remains in good agreement with the theoretical prediction of (3.64 \pm 0.12) x 10^-9 within the Standard Model. In the present paper, we review calculations that have contributed to this prediction, and discuss the associated uncertainties.
1205.6983
Mikhail Vysotsky
M. I. Vysotsky
Photon "mass" and atomic levels in a superstrong magnetic field
Contribution to the proceedings of the LOWDIM Workshop devoted to Sergei Gaikovich Matinyan 80'th birthday; 6 pages, 2 figures
null
10.1142/9789814440349_0022
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The structure of atomic levels originating from the lowest Landau level in a superstrong magnetic field is analyzed. The influence of the screening of the Coulomb potential on the values of critical nuclear charge is studied.
[ { "created": "Thu, 31 May 2012 12:59:31 GMT", "version": "v1" } ]
2017-08-23
[ [ "Vysotsky", "M. I.", "" ] ]
The structure of atomic levels originating from the lowest Landau level in a superstrong magnetic field is analyzed. The influence of the screening of the Coulomb potential on the values of critical nuclear charge is studied.
hep-ph/0311172
Ricard Tomas
A. S. Dighe, M. Kachelriess, G. G. Raffelt and R. Tomas
Signatures of supernova neutrino oscillations in the Earth mantle and core
17 pages, 9 figures
JCAP 0401 (2004) 004
10.1088/1475-7516/2004/01/004
MPP-2003-126
hep-ph astro-ph
null
The Earth matter effects on supernova (SN) neutrinos can be identified at a single detector through peaks in the Fourier transform of their ``inverse energy'' spectrum. The positions of these peaks are independent of the SN models and therefore the peaks can be used as a robust signature of the Earth matter effects, which in turn can distinguish between different neutrino mixing scenarios. Whereas only one genuine peak is observable when the neutrinos traverse only the Earth mantle, traversing also the core gives rise to multiple peaks. We calculate the strengths and positions of these peaks analytically and explore their features at a large scintillation detector as well as at a megaton water Cherenkov detector through Monte Carlo simulations. We propose a simple algorithm to identify the peaks in the actual data and quantify the chances of a peak identification as a function of the location of the SN in the sky.
[ { "created": "Thu, 13 Nov 2003 17:52:57 GMT", "version": "v1" } ]
2009-11-10
[ [ "Dighe", "A. S.", "" ], [ "Kachelriess", "M.", "" ], [ "Raffelt", "G. G.", "" ], [ "Tomas", "R.", "" ] ]
The Earth matter effects on supernova (SN) neutrinos can be identified at a single detector through peaks in the Fourier transform of their ``inverse energy'' spectrum. The positions of these peaks are independent of the SN models and therefore the peaks can be used as a robust signature of the Earth matter effects, which in turn can distinguish between different neutrino mixing scenarios. Whereas only one genuine peak is observable when the neutrinos traverse only the Earth mantle, traversing also the core gives rise to multiple peaks. We calculate the strengths and positions of these peaks analytically and explore their features at a large scintillation detector as well as at a megaton water Cherenkov detector through Monte Carlo simulations. We propose a simple algorithm to identify the peaks in the actual data and quantify the chances of a peak identification as a function of the location of the SN in the sky.
2303.12006
Eric Moffat
Eric Moffat, Adam Freese, Ian Clo\"et, Thomas Donohoe, Leonard Gamberg, Wally Melnitchouk, Andreas Metz, Alexei Prokudin, Nobuo Sato
Shedding light on shadow generalized parton distributions
15 pages, 5 figures
null
null
null
hep-ph nucl-ex nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The feasibility of extracting generalized parton distributions (GPDs) from deeply-virtual Compton scattering (DVCS) data has recently been questioned because of the existence of an infinite set of so-called ''shadow GPDs'' (SGPDs). These SGPDs depend on the process and manifest as multiple solutions (at a fixed scale $Q^2$) to the inverse problem that needs to be solved to infer GPDs from DVCS data. SGPDs therefore pose a significant challenge for extracting GPDs from DVCS data. With this motivation we study the extent to which QCD evolution can provide constraints on SGPDs. This is possible because the known classes of SGPDs begin to contribute to observables after evolution, and can then be constrained (at the input scale $Q^2_0$) by data that has a finite $Q^2$ range. The impact that SGPDs could have on determining the total angular momentum, pressure and sheer force distributions, and tomography is also discussed. Our key finding is that scale evolution, coupled with data over a wide range of skewness $\xi$ and $Q^2$, can constrain the class of SGPDs that we studied and potentially make possible the extraction of GPDs from DVCS data over a limited range in the GPD variables.
[ { "created": "Tue, 21 Mar 2023 16:38:04 GMT", "version": "v1" } ]
2023-03-24
[ [ "Moffat", "Eric", "" ], [ "Freese", "Adam", "" ], [ "Cloët", "Ian", "" ], [ "Donohoe", "Thomas", "" ], [ "Gamberg", "Leonard", "" ], [ "Melnitchouk", "Wally", "" ], [ "Metz", "Andreas", "" ], [ "Prokudin", "Alexei", "" ], [ "Sato", "Nobuo", "" ] ]
The feasibility of extracting generalized parton distributions (GPDs) from deeply-virtual Compton scattering (DVCS) data has recently been questioned because of the existence of an infinite set of so-called ''shadow GPDs'' (SGPDs). These SGPDs depend on the process and manifest as multiple solutions (at a fixed scale $Q^2$) to the inverse problem that needs to be solved to infer GPDs from DVCS data. SGPDs therefore pose a significant challenge for extracting GPDs from DVCS data. With this motivation we study the extent to which QCD evolution can provide constraints on SGPDs. This is possible because the known classes of SGPDs begin to contribute to observables after evolution, and can then be constrained (at the input scale $Q^2_0$) by data that has a finite $Q^2$ range. The impact that SGPDs could have on determining the total angular momentum, pressure and sheer force distributions, and tomography is also discussed. Our key finding is that scale evolution, coupled with data over a wide range of skewness $\xi$ and $Q^2$, can constrain the class of SGPDs that we studied and potentially make possible the extraction of GPDs from DVCS data over a limited range in the GPD variables.
1410.7684
Susanne Mertens Dr.
S. Mertens, K. Dolde, M. Korzeczek, F. Glueck, S. Groh, R. D. Martin, A. W. P. Poon, M. Steidl
Wavelet Approach to Search for Sterile Neutrinos in Tritium $\beta$-Decay Spectra
null
Phys. Rev. D 91, 042005 (2015)
10.1103/PhysRevD.91.042005
null
hep-ph astro-ph.CO hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Sterile neutrinos in the mass range of a few keV are candidates for both cold and warm dark matter. An ad-mixture of a heavy neutrino mass eigenstate to the electron neutrino would result in a minuscule distortion - a 'kink' - in a $\beta$-decay spectrum. In this paper we show that a wavelet transform is a very powerful shape analysis method to detect this signature. For a tritium source strength, similar to what is expected from the KATRIN experiment, a statistical sensitivity to active-to-sterile neutrino mixing down to $\sin^2 \theta= 10^{-6}$ ($90\%$ CL) can be obtained after 3 years of measurement time. It is demonstrated that the wavelet approach is largely insensitive to systematic effects that result in smooth spectral modifications. To make full use of this analysis technique a high resolution measurement (FWHM of $\sim100$~eV) of the tritium $\beta$-decay spectrum is required.
[ { "created": "Mon, 27 Oct 2014 18:09:11 GMT", "version": "v1" }, { "created": "Thu, 8 Jan 2015 13:24:16 GMT", "version": "v2" } ]
2015-03-05
[ [ "Mertens", "S.", "" ], [ "Dolde", "K.", "" ], [ "Korzeczek", "M.", "" ], [ "Glueck", "F.", "" ], [ "Groh", "S.", "" ], [ "Martin", "R. D.", "" ], [ "Poon", "A. W. P.", "" ], [ "Steidl", "M.", "" ] ]
Sterile neutrinos in the mass range of a few keV are candidates for both cold and warm dark matter. An ad-mixture of a heavy neutrino mass eigenstate to the electron neutrino would result in a minuscule distortion - a 'kink' - in a $\beta$-decay spectrum. In this paper we show that a wavelet transform is a very powerful shape analysis method to detect this signature. For a tritium source strength, similar to what is expected from the KATRIN experiment, a statistical sensitivity to active-to-sterile neutrino mixing down to $\sin^2 \theta= 10^{-6}$ ($90\%$ CL) can be obtained after 3 years of measurement time. It is demonstrated that the wavelet approach is largely insensitive to systematic effects that result in smooth spectral modifications. To make full use of this analysis technique a high resolution measurement (FWHM of $\sim100$~eV) of the tritium $\beta$-decay spectrum is required.
hep-ph/0307055
Hou Hong-Sheng
Hou Hong-Sheng, Ma Wen-Gan, Wu Peng, Wang Lei and Zhang Ren-You
Higgs-Boson Production Associated with a Single Bottom Quark in Supersymmetric QCD
accepted by Phys. Rev. D
Phys.Rev. D68 (2003) 035016
10.1103/PhysRevD.68.035016
null
hep-ph
null
Due to the enhancement of the couplings between Higgs boson and bottom quarks in the minimal sypersymmetric standard model (MSSM), the cross section of the process pp(p\bar{p}) \to h^0b(h^0\bar{b})+X at hadron colliders can be considerably enhanced. We investigated the production of Higgs boson associated with a single high-p_T bottom quark via subprocess bg(\bar{b}g) \to h^0b(h^0\bar{b}) at hadron colliders including the next-to-leading order (NLO) QCD corrections in MSSM. We find that the NLO QCD correction in the MSSM reaches 50%-70% at the LHC and 60%-85% at the Fermilab Tevatron in our chosen parameter space.
[ { "created": "Fri, 4 Jul 2003 08:12:58 GMT", "version": "v1" } ]
2009-11-10
[ [ "Hong-Sheng", "Hou", "" ], [ "Wen-Gan", "Ma", "" ], [ "Peng", "Wu", "" ], [ "Lei", "Wang", "" ], [ "Ren-You", "Zhang", "" ] ]
Due to the enhancement of the couplings between Higgs boson and bottom quarks in the minimal sypersymmetric standard model (MSSM), the cross section of the process pp(p\bar{p}) \to h^0b(h^0\bar{b})+X at hadron colliders can be considerably enhanced. We investigated the production of Higgs boson associated with a single high-p_T bottom quark via subprocess bg(\bar{b}g) \to h^0b(h^0\bar{b}) at hadron colliders including the next-to-leading order (NLO) QCD corrections in MSSM. We find that the NLO QCD correction in the MSSM reaches 50%-70% at the LHC and 60%-85% at the Fermilab Tevatron in our chosen parameter space.
hep-ph/0209304
Leonard Lesniak
Agnieszka Furman and Leonard Lesniak
Properties of the a0 resonances
4 pages, 3 figures, needs espcrc2.sty. Talk given by L. Lesniak at the QCD 2002 Conference, Montpellier, France, 2-9 July 2002; to be published in the proceedings
null
10.1016/S0920-5632(03)01827-9
null
hep-ph
null
We present results following from the coupled channel model of two a0 resonances decaying into the pi-eta and K anti-K mesons. The a0(980) resonance can be described by two distinct poles. It is shown that the discrepancy in the a0(980) mass position between the Crystal Barrel Collaboration and the E852 Group can be explained and removed. In our model with parameters fixed by the present experimental data the a0(980) cannot be interpreted as a bound K anti-K state although the K anti-K forces in the S-wave isovector channel are attractive.
[ { "created": "Wed, 25 Sep 2002 15:51:23 GMT", "version": "v1" } ]
2009-11-07
[ [ "Furman", "Agnieszka", "" ], [ "Lesniak", "Leonard", "" ] ]
We present results following from the coupled channel model of two a0 resonances decaying into the pi-eta and K anti-K mesons. The a0(980) resonance can be described by two distinct poles. It is shown that the discrepancy in the a0(980) mass position between the Crystal Barrel Collaboration and the E852 Group can be explained and removed. In our model with parameters fixed by the present experimental data the a0(980) cannot be interpreted as a bound K anti-K state although the K anti-K forces in the S-wave isovector channel are attractive.
2311.00864
Florian Herren
Erik J. Gustafson, Florian Herren, Ruth S. Van de Water, Raynette van Tonder, Michael L. Wagman
A model independent description of $B\rightarrow D \pi \ell \nu$ decays
10 pages, 3 wonderful figures
null
null
FERMILAB-PUB-23-662-T, ZU-TH 67/23
hep-ph hep-ex hep-lat
http://creativecommons.org/licenses/by/4.0/
We introduce a new parameterization of $B\rightarrow D \pi \ell \nu$ form factors using a partial-wave expansion and derive bounds on the series coefficients using analyticity and unitarity. This is the first generalization of the model-independent formalism developed by Boyd, Grinstein, and Lebed for $B \to D \ell \nu$ to semileptonic decays with multi-hadron final states, and enables data-driven form factor determinations with robust, systematically-improvable uncertainties. Using this formalism, we extract the form-factor parameters for $B \to D_2^\ast(\to D\pi) \ell \nu$ decays in a model-independent way from fits of data from the Belle Experiment, and, for the first time, study the two-pole structure in the $D\pi$ S-wave in semileptonic decays employing lineshapes from unitarized chiral perturbation theory.
[ { "created": "Wed, 1 Nov 2023 21:35:23 GMT", "version": "v1" } ]
2023-11-03
[ [ "Gustafson", "Erik J.", "" ], [ "Herren", "Florian", "" ], [ "Van de Water", "Ruth S.", "" ], [ "van Tonder", "Raynette", "" ], [ "Wagman", "Michael L.", "" ] ]
We introduce a new parameterization of $B\rightarrow D \pi \ell \nu$ form factors using a partial-wave expansion and derive bounds on the series coefficients using analyticity and unitarity. This is the first generalization of the model-independent formalism developed by Boyd, Grinstein, and Lebed for $B \to D \ell \nu$ to semileptonic decays with multi-hadron final states, and enables data-driven form factor determinations with robust, systematically-improvable uncertainties. Using this formalism, we extract the form-factor parameters for $B \to D_2^\ast(\to D\pi) \ell \nu$ decays in a model-independent way from fits of data from the Belle Experiment, and, for the first time, study the two-pole structure in the $D\pi$ S-wave in semileptonic decays employing lineshapes from unitarized chiral perturbation theory.
2011.00473
Chao Han
Chao Han, Chun Liu
b-baryon semi-tauonic decays in the Standard Model
20 pages, 7 figures and 1 table; v2: reference added
null
10.1016/j.nuclphysb.2020.115262
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Within the framework of HQET, $\Lambda_{b}\rightarrow\Lambda_{c}\tau\bar{\nu}_{\tau}$ and $\Omega_{b}\rightarrow\Omega_{c}^{(*)}\tau\bar{\nu}_{\tau}$ weak decays are studied to the order of $1/m_c$ and $1/m_b$. Helicity amplitudes are written down. Relevant Isgur-Wise functions given by QCD sum rule and large $N_c$ methods are applied in the numerical analysis. The baryonic R-ratios $R(\Lambda_c)$ and $R(\Omega_c^{(*)})$ are obtained.
[ { "created": "Sun, 1 Nov 2020 10:57:32 GMT", "version": "v1" }, { "created": "Sun, 6 Dec 2020 13:54:41 GMT", "version": "v2" } ]
2021-02-03
[ [ "Han", "Chao", "" ], [ "Liu", "Chun", "" ] ]
Within the framework of HQET, $\Lambda_{b}\rightarrow\Lambda_{c}\tau\bar{\nu}_{\tau}$ and $\Omega_{b}\rightarrow\Omega_{c}^{(*)}\tau\bar{\nu}_{\tau}$ weak decays are studied to the order of $1/m_c$ and $1/m_b$. Helicity amplitudes are written down. Relevant Isgur-Wise functions given by QCD sum rule and large $N_c$ methods are applied in the numerical analysis. The baryonic R-ratios $R(\Lambda_c)$ and $R(\Omega_c^{(*)})$ are obtained.
0812.1798
Brooks Thomas
Shufang Su and Brooks Thomas
h-> mu^+ mu^- via tth Production at the LHC
11 pages, ReVTeX, 1 figure, 5 tables
Phys.Lett.B677:296-300,2009
10.1016/j.physletb.2009.05.027
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this work, we examine the process at the LHC in which a Higgs boson is produced in association with a t t-bar pair and subsequently decays to a pair of muons. We show that the statistical significance for the discovery of a light, Standard-Model Higgs boson with a mass around 120 GeV in this channel is comparable to those for other processes (gluon fusion, weak-boson fusion) in which the Higgs decays to a muon pair. Combining all three of these channels, we show that evidence for a Higgs boson with a mass in the range 115 GeV < m_h < 130 GeV could be obtained at the 3 sigma significance level with an integrated luminosity of 300 fb^{-1}. We also calculate the enhancement factor to the cross-section that would be needed to discover a non-standard Higgs boson in this channel.
[ { "created": "Tue, 9 Dec 2008 21:12:25 GMT", "version": "v1" } ]
2014-11-18
[ [ "Su", "Shufang", "" ], [ "Thomas", "Brooks", "" ] ]
In this work, we examine the process at the LHC in which a Higgs boson is produced in association with a t t-bar pair and subsequently decays to a pair of muons. We show that the statistical significance for the discovery of a light, Standard-Model Higgs boson with a mass around 120 GeV in this channel is comparable to those for other processes (gluon fusion, weak-boson fusion) in which the Higgs decays to a muon pair. Combining all three of these channels, we show that evidence for a Higgs boson with a mass in the range 115 GeV < m_h < 130 GeV could be obtained at the 3 sigma significance level with an integrated luminosity of 300 fb^{-1}. We also calculate the enhancement factor to the cross-section that would be needed to discover a non-standard Higgs boson in this channel.
hep-ph/0205146
Rogerio Rosenfeld
A. Chalov, A. Likhoded and R. Rosenfeld
Measuring Higgs Coupling to Tau-Leptons at Future e+ e- Colliders
10 pages, 10 figures
J.Phys.G29:337-348,2003
10.1088/0954-3899/29/2/310
IFT-P.034/2002
hep-ph
null
We perform a complete simulation of the process $ e^+ e^- \to \tau^+ \tau^- \nu \bar{\nu}$, where $\nu$ can be an electron, muon or tau neutrino, in the context of a general Higgs coupling to $\tau$ leptons. We analyse various kinematical distributions and obtain the sensitivity regions in the parameter space that can be explored at a future $e^+ e^-$ collider. In particular, inclusion of $W$ boson fusion enhances the sensitivity significantly.
[ { "created": "Tue, 14 May 2002 20:00:57 GMT", "version": "v1" } ]
2008-11-26
[ [ "Chalov", "A.", "" ], [ "Likhoded", "A.", "" ], [ "Rosenfeld", "R.", "" ] ]
We perform a complete simulation of the process $ e^+ e^- \to \tau^+ \tau^- \nu \bar{\nu}$, where $\nu$ can be an electron, muon or tau neutrino, in the context of a general Higgs coupling to $\tau$ leptons. We analyse various kinematical distributions and obtain the sensitivity regions in the parameter space that can be explored at a future $e^+ e^-$ collider. In particular, inclusion of $W$ boson fusion enhances the sensitivity significantly.
1403.7518
Keith Olive
John Ellis, Marcos A. G. Garcia, Dimitri V. Nanopoulos, Keith A. Olive
Resurrecting Quadratic Inflation in No-Scale Supergravity in Light of BICEP2
24 pages, 14 figures
null
10.1088/1475-7516/2014/05/037
KCL-PH-TH/2014-11, LCTS/2014-11, CERN-PH-TH/2014-049, ACT-3-14, UMN-TH-3332/14, FTPI-MINN-14/10
hep-ph astro-ph.CO gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The magnitude of primordial tensor perturbations reported by the BICEP2 experiment is consistent with simple models of chaotic inflation driven by a single scalar field with a power-law potential \propto \phi^n: n \simeq 2, in contrast to the WMAP and Planck results, which favored models resembling the Starobinsky R + R^2 model if running of the scalar spectral index could be neglected. While models of inflation with a quadratic potential may be constructed in simple N=1 supergravity, these constructions are more challenging in no-scale supergravity. We discuss here how quadratic inflation can be accommodated within supergravity, focussing primarily on the no-scale case. We also argue that the quadratic inflaton may be identified with the supersymmetric partner of a singlet (right-handed) neutrino, whose subsequent decay could have generated the baryon asymmetry via leptogenesis.
[ { "created": "Fri, 28 Mar 2014 19:54:45 GMT", "version": "v1" }, { "created": "Fri, 4 Apr 2014 19:51:30 GMT", "version": "v2" } ]
2015-06-19
[ [ "Ellis", "John", "" ], [ "Garcia", "Marcos A. G.", "" ], [ "Nanopoulos", "Dimitri V.", "" ], [ "Olive", "Keith A.", "" ] ]
The magnitude of primordial tensor perturbations reported by the BICEP2 experiment is consistent with simple models of chaotic inflation driven by a single scalar field with a power-law potential \propto \phi^n: n \simeq 2, in contrast to the WMAP and Planck results, which favored models resembling the Starobinsky R + R^2 model if running of the scalar spectral index could be neglected. While models of inflation with a quadratic potential may be constructed in simple N=1 supergravity, these constructions are more challenging in no-scale supergravity. We discuss here how quadratic inflation can be accommodated within supergravity, focussing primarily on the no-scale case. We also argue that the quadratic inflaton may be identified with the supersymmetric partner of a singlet (right-handed) neutrino, whose subsequent decay could have generated the baryon asymmetry via leptogenesis.
hep-ph/0207032
Giuseppe Nardulli
L. Angelini, P. De Felice, M. Maggi, G. Nardulli, L.Nitti, M. Pellicoro and S. Stramaglia
Jet analysis by Deterministic Annealing
15 pages, 4 figures
Phys.Lett. B545 (2002) 315-322
10.1016/S0370-2693(02)02475-9
BARI-TH 443/02
hep-ph
null
We perform a comparison of two jet clusterization algorithms. The first one is the standard Durham algorithm and the second one is a global optimization scheme, Deterministic Annealing, often used in clusterization problems, and adapted to the problem of jet identification in particle production by high energy collisions; in particular we study hadronic jets in WW production by high energy electron positron scattering. Our results are as follows. First, we find that the two procedures give basically the same output as far as the particle clusterization is concerned. Second, we find that the increase of CPU time with the particle multiplicity is much faster for the Durham jet clustering algorithm in comparison with Deterministic Annealing. Since this result follows from the higher computational complexity of the Durham scheme, it should not depend on the particular process studied here and might be significant for jet physics at LHC as well.
[ { "created": "Tue, 2 Jul 2002 10:43:27 GMT", "version": "v1" } ]
2009-11-07
[ [ "Angelini", "L.", "" ], [ "De Felice", "P.", "" ], [ "Maggi", "M.", "" ], [ "Nardulli", "G.", "" ], [ "Nitti", "L.", "" ], [ "Pellicoro", "M.", "" ], [ "Stramaglia", "S.", "" ] ]
We perform a comparison of two jet clusterization algorithms. The first one is the standard Durham algorithm and the second one is a global optimization scheme, Deterministic Annealing, often used in clusterization problems, and adapted to the problem of jet identification in particle production by high energy collisions; in particular we study hadronic jets in WW production by high energy electron positron scattering. Our results are as follows. First, we find that the two procedures give basically the same output as far as the particle clusterization is concerned. Second, we find that the increase of CPU time with the particle multiplicity is much faster for the Durham jet clustering algorithm in comparison with Deterministic Annealing. Since this result follows from the higher computational complexity of the Durham scheme, it should not depend on the particular process studied here and might be significant for jet physics at LHC as well.
0907.0030
Karol Kovarik
Bjorn Herrmann, Michael Klasen, Karol Kovarik
SUSY-QCD effects on neutralino dark matter annihilation beyond scalar or gaugino mass unification
27 pages
Phys.Rev.D80:085025,2009
10.1103/PhysRevD.80.085025
LPSC 09-082
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We describe in detail our calculation of the full supersymmetric (SUSY) QCD corrections to neutralino annihilation into heavy quarks and extend our numerical analysis of the resulting dark matter relic density to scenarios without scalar or gaugino mass unification. In these scenarios, the final state is often composed of top quarks and the annihilation proceeds through Z^0-boson or scalar top-quark exchanges. The impact of the corrections is again shown to be sizable, so that they must be taken into account systematically in global analyses of the supersymmetry parameter space.
[ { "created": "Tue, 30 Jun 2009 22:01:19 GMT", "version": "v1" }, { "created": "Tue, 25 Aug 2009 13:40:53 GMT", "version": "v2" } ]
2009-11-05
[ [ "Herrmann", "Bjorn", "" ], [ "Klasen", "Michael", "" ], [ "Kovarik", "Karol", "" ] ]
We describe in detail our calculation of the full supersymmetric (SUSY) QCD corrections to neutralino annihilation into heavy quarks and extend our numerical analysis of the resulting dark matter relic density to scenarios without scalar or gaugino mass unification. In these scenarios, the final state is often composed of top quarks and the annihilation proceeds through Z^0-boson or scalar top-quark exchanges. The impact of the corrections is again shown to be sizable, so that they must be taken into account systematically in global analyses of the supersymmetry parameter space.
hep-ph/0101075
Albert De Roeck
A. De Roeck
Two Photon Physics at Future Linear Colliders
8 pages, 5 figures To be published in the proceedings of Photon 2000, Ambelside, England, 26-31 August 2000
null
10.1063/1.1402867
null
hep-ph
null
Prospects for QCD studies in two-photon interactions at a future linear e+e- and gamma-gamma collider are discussed.
[ { "created": "Tue, 9 Jan 2001 11:24:33 GMT", "version": "v1" } ]
2009-11-07
[ [ "De Roeck", "A.", "" ] ]
Prospects for QCD studies in two-photon interactions at a future linear e+e- and gamma-gamma collider are discussed.
hep-ph/0102201
Nigel Glover
E.W.N. Glover, C. Oleari and M.E. Tejeda-Yeomans
Two-loop QCD corrections to gluon-gluon scattering
20 pages, LaTeX, JHEP class, typo fixed
Nucl.Phys.B605:467-485,2001
10.1016/S0550-3213(01)00210-3
IPPP/01/07, DCTP/01/14, MADPH-01-1217
hep-ph
null
We present the O(alpha_s^4) virtual QCD corrections to gluon-gluon scattering due to the interference of tree and two-loop amplitudes. We work in conventional dimensional regularisation and give analytic expressions renormalised in the MSbar scheme. The structure of the infrared divergences agrees with that predicted by Catani while formulae for the finite remainder are given in terms of logarithms and polylogarithms that are real in the physical region. These results, together with those previously obtained for quark-quark and quark-gluon scattering, complete the two-loop matrix elements needed for the next-to-next-to-leading order contribution to inclusive jet production at hadron colliders.
[ { "created": "Thu, 15 Feb 2001 23:18:53 GMT", "version": "v1" }, { "created": "Tue, 27 Nov 2001 22:37:40 GMT", "version": "v2" } ]
2010-04-06
[ [ "Glover", "E. W. N.", "" ], [ "Oleari", "C.", "" ], [ "Tejeda-Yeomans", "M. E.", "" ] ]
We present the O(alpha_s^4) virtual QCD corrections to gluon-gluon scattering due to the interference of tree and two-loop amplitudes. We work in conventional dimensional regularisation and give analytic expressions renormalised in the MSbar scheme. The structure of the infrared divergences agrees with that predicted by Catani while formulae for the finite remainder are given in terms of logarithms and polylogarithms that are real in the physical region. These results, together with those previously obtained for quark-quark and quark-gluon scattering, complete the two-loop matrix elements needed for the next-to-next-to-leading order contribution to inclusive jet production at hadron colliders.
0804.1096
Aleksey Cherman
Aleksey Cherman, Thomas D. Cohen, Elizabeth S. Werbos
The chiral condensate in holographic models of QCD
5 pages, fixed typos in Eq. 6 and in text after Eq. 13
Phys.Rev.C79:045203,2009
10.1103/PhysRevC.79.045203
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Bottom-up holographic models of QCD, inspired by the AdS/CFT correspondence, have shown a remarkable degree of phenomenological success. However, they rely on a number of bold assumptions. We investigate the reliability of one of the key assumptions, which involves matching the parameters of these models to QCD at high 4D momentum $q^2$ and renormalization scale $\mu^2$. We show that this leads to phenomenological and theoretical inconsistencies for scale-dependent quantities such as $\bra \bar{q}q\ket$
[ { "created": "Mon, 7 Apr 2008 17:59:46 GMT", "version": "v1" }, { "created": "Wed, 16 Apr 2008 18:54:33 GMT", "version": "v2" }, { "created": "Fri, 12 Mar 2010 15:37:15 GMT", "version": "v3" } ]
2010-03-16
[ [ "Cherman", "Aleksey", "" ], [ "Cohen", "Thomas D.", "" ], [ "Werbos", "Elizabeth S.", "" ] ]
Bottom-up holographic models of QCD, inspired by the AdS/CFT correspondence, have shown a remarkable degree of phenomenological success. However, they rely on a number of bold assumptions. We investigate the reliability of one of the key assumptions, which involves matching the parameters of these models to QCD at high 4D momentum $q^2$ and renormalization scale $\mu^2$. We show that this leads to phenomenological and theoretical inconsistencies for scale-dependent quantities such as $\bra \bar{q}q\ket$
1810.10543
Torsten Bringmann
Torsten Bringmann and Maxim Pospelov
Novel direct detection constraints on light dark matter
7 pages revtex4, 3 figures. Version to appear in Phys. Rev. Lett
Phys. Rev. Lett. 122, 171801 (2019)
10.1103/PhysRevLett.122.171801
null
hep-ph astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
All attempts to directly detect particle dark matter (DM) scattering on nuclei suffer from the partial or total loss of sensitivity for DM masses in the GeV range or below. We derive novel constraints from the inevitable existence of a subdominant, but highly energetic, component of DM generated through collisions with cosmic rays. Subsequent scattering inside conventional DM detectors, as well as neutrino detectors sensitive to nuclear recoils, limits the DM-nucleon scattering cross section to be below $10^{-31}$ cm$^2$ for both spin-independent and spin-dependent scattering of light DM.
[ { "created": "Wed, 24 Oct 2018 18:00:01 GMT", "version": "v1" }, { "created": "Tue, 9 Apr 2019 20:53:50 GMT", "version": "v2" } ]
2019-05-08
[ [ "Bringmann", "Torsten", "" ], [ "Pospelov", "Maxim", "" ] ]
All attempts to directly detect particle dark matter (DM) scattering on nuclei suffer from the partial or total loss of sensitivity for DM masses in the GeV range or below. We derive novel constraints from the inevitable existence of a subdominant, but highly energetic, component of DM generated through collisions with cosmic rays. Subsequent scattering inside conventional DM detectors, as well as neutrino detectors sensitive to nuclear recoils, limits the DM-nucleon scattering cross section to be below $10^{-31}$ cm$^2$ for both spin-independent and spin-dependent scattering of light DM.
1007.4512
Luis Alvarez-Ruso
L. Alvarez-Ruso, J. A. Oller and J. M. Alarcon
The phi(1020) a0(980) S-wave scattering and hints for a new vector-isovector resonance
16 pages, 9 figures, 2 tables
Phys.Rev.D82:094028,2010
10.1103/PhysRevD.82.094028
null
hep-ph hep-ex nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We have studied the phi(1020)a0(980) S-wave scattering at threshold energies employing chiral Lagrangians coupled to vector mesons by minimal coupling. The interaction is described without new free parameters by considering the scalar isovector a0(980) resonance as dynamically generated in coupled channels, and demanding that the recently measured e+ e- -> phi(1020) f0(980) cross section is reproduced. For some realistic choices of the parameters, the presence of a dynamically generated isovector companion of the Y(2175) is revealed. We have also investigated the corrections to the e+ e- -> phi(1020) pi0 eta reaction cross section that arise from phi(1020)a0(980) re-scattering in the final state. They are typically large and modify substantially the cross section. For a suitable choice of parameters, the presence of the resonance would manifest itself as a clear peak at sqrt{s}~2.03 GeV in e+ e- -> phi(1020) pi0 eta.
[ { "created": "Mon, 26 Jul 2010 17:35:18 GMT", "version": "v1" } ]
2010-12-23
[ [ "Alvarez-Ruso", "L.", "" ], [ "Oller", "J. A.", "" ], [ "Alarcon", "J. M.", "" ] ]
We have studied the phi(1020)a0(980) S-wave scattering at threshold energies employing chiral Lagrangians coupled to vector mesons by minimal coupling. The interaction is described without new free parameters by considering the scalar isovector a0(980) resonance as dynamically generated in coupled channels, and demanding that the recently measured e+ e- -> phi(1020) f0(980) cross section is reproduced. For some realistic choices of the parameters, the presence of a dynamically generated isovector companion of the Y(2175) is revealed. We have also investigated the corrections to the e+ e- -> phi(1020) pi0 eta reaction cross section that arise from phi(1020)a0(980) re-scattering in the final state. They are typically large and modify substantially the cross section. For a suitable choice of parameters, the presence of the resonance would manifest itself as a clear peak at sqrt{s}~2.03 GeV in e+ e- -> phi(1020) pi0 eta.
1607.04635
Lucian Harland-Lang
L.A. Harland-Lang, V.A. Khoze, M.G. Ryskin
Photon-initiated processes at high mass
16 pages, 6 figures. References added and discussion clarified. Version accepted for publication in PRD
Phys. Rev. D 94, 074008 (2016)
10.1103/PhysRevD.94.074008
IPPP/16/67
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider the influence of photon-initiated processes on high-mass particle production. We discuss in detail the photon PDF at relatively high parton $x$, relevant to such processes, and evaluate its uncertainties. In particular we show that, as the dominant contribution to the input photon distribution is due to coherent photon emission, at phenomenologically relevant scales the photon PDF is already well determined in this region, with the corresponding uncertainties under good control. We then demonstrate the implications of this result for the example processes of high-mass lepton and $W$ boson pair production at the LHC and FCC. While for the former process the photon-initiated contribution is expected to be small, in the latter case we find that it is potentially significant, in particular at larger masses.
[ { "created": "Fri, 15 Jul 2016 19:57:38 GMT", "version": "v1" }, { "created": "Mon, 1 Aug 2016 13:58:01 GMT", "version": "v2" }, { "created": "Mon, 10 Oct 2016 12:29:19 GMT", "version": "v3" } ]
2016-10-12
[ [ "Harland-Lang", "L. A.", "" ], [ "Khoze", "V. A.", "" ], [ "Ryskin", "M. G.", "" ] ]
We consider the influence of photon-initiated processes on high-mass particle production. We discuss in detail the photon PDF at relatively high parton $x$, relevant to such processes, and evaluate its uncertainties. In particular we show that, as the dominant contribution to the input photon distribution is due to coherent photon emission, at phenomenologically relevant scales the photon PDF is already well determined in this region, with the corresponding uncertainties under good control. We then demonstrate the implications of this result for the example processes of high-mass lepton and $W$ boson pair production at the LHC and FCC. While for the former process the photon-initiated contribution is expected to be small, in the latter case we find that it is potentially significant, in particular at larger masses.
hep-ph/0204090
Emmanuel A. Paschos
E.A. Paschos
Precise Ratios for Neutrino-Nucleon and Neutrino-Nucleus Interactions
11 pages
null
null
DO-TH 02/02
hep-ph
null
It is shown that several ratios of neutral to charged current cross sections are determined accurately, because the largest contribution is determined by isospin symmetry and the smaller terms are estimated from data or theoretical calculations. This way the theoretical uncertainty is very small. It is further discussed that the ratios can be measured at various distances from the origin of the neutrino beams, because an increase with distance will be indication for neutrino oscillations and will allow a precise determination of the oscillation parameters. Finally, coherent scattering is discussed as a useful reaction for oscillations and as a means of searching for new light particles.
[ { "created": "Mon, 8 Apr 2002 14:41:33 GMT", "version": "v1" }, { "created": "Tue, 7 May 2002 12:44:47 GMT", "version": "v2" } ]
2007-05-23
[ [ "Paschos", "E. A.", "" ] ]
It is shown that several ratios of neutral to charged current cross sections are determined accurately, because the largest contribution is determined by isospin symmetry and the smaller terms are estimated from data or theoretical calculations. This way the theoretical uncertainty is very small. It is further discussed that the ratios can be measured at various distances from the origin of the neutrino beams, because an increase with distance will be indication for neutrino oscillations and will allow a precise determination of the oscillation parameters. Finally, coherent scattering is discussed as a useful reaction for oscillations and as a means of searching for new light particles.
0909.3015
Jacopo Bechi
Jacopo Bechi
Instantons and quark zero modes in AdS/QCD
12 pages, no figure
null
null
CP3-Origins: 2009-15
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper the quark zero modes creation effect is studied in the context of the AdS/QCD approach. This effect is generated, in presence of instantons, by a new that can be added in the bulk.
[ { "created": "Wed, 16 Sep 2009 14:45:53 GMT", "version": "v1" } ]
2009-09-17
[ [ "Bechi", "Jacopo", "" ] ]
In this paper the quark zero modes creation effect is studied in the context of the AdS/QCD approach. This effect is generated, in presence of instantons, by a new that can be added in the bulk.
1103.5307
J.D. Vergados
J.D. Vergados (University of Ioannina, Ioannina, Greece), Y. Giomataris (CEA, Saclay, DAPNIA, Gif-sur-Yvette, Cedex, France), Yu.N. Novikov (Petersburg Nuclear Physics Institute, Gatchina, Russia and St.Petersburg State University, St.Petersburg, Russia)
Probing the fourth neutrino existence by neutral current oscillometry in the spherical gaseous TPC
18 LaTex pages, 11 figures, 2 tables
Nucl.Phys.B854:54-66,2012
10.1016/j.nuclphysb.2011.08.018
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It is shown that, if the "new neutrino" implied by the Reactor Neutrino Anomaly exists and is in fact characterized by the suggested relatively high mass squared difference and reasonably large mixing angle, it should clearly reveal itself in the oscillometry measurements. For a judicious neutrino source the "new oscillation length L14 is expected shorter than 3m. Thus the needed measurements can be implemented with a gaseous spherical TPC of modest dimensions with a very good energy and position resolution, detecting nuclear recoils following the coherent neutrino-nucleus elastic scattering. The best candidates for oscillometry, yielding both monochromatic neutrinos as well as antineutrinos, are discussed. A sensitivity in the mixing angle theta14, (sin(2\theta14))^2=0.1 (99 %), can be reached after a few months of data handling.
[ { "created": "Mon, 28 Mar 2011 09:47:47 GMT", "version": "v1" }, { "created": "Tue, 29 Mar 2011 10:56:33 GMT", "version": "v2" } ]
2011-09-28
[ [ "Vergados", "J. D.", "", "University of Ioannina, Ioannina, Greece" ], [ "Giomataris", "Y.", "", "CEA, Saclay, DAPNIA, Gif-sur-Yvette, Cedex, France" ], [ "Novikov", "Yu. N.", "", "Petersburg Nuclear Physics Institute, Gatchina, Russia and\n St.Petersburg State University, St.Petersburg, Russia" ] ]
It is shown that, if the "new neutrino" implied by the Reactor Neutrino Anomaly exists and is in fact characterized by the suggested relatively high mass squared difference and reasonably large mixing angle, it should clearly reveal itself in the oscillometry measurements. For a judicious neutrino source the "new oscillation length L14 is expected shorter than 3m. Thus the needed measurements can be implemented with a gaseous spherical TPC of modest dimensions with a very good energy and position resolution, detecting nuclear recoils following the coherent neutrino-nucleus elastic scattering. The best candidates for oscillometry, yielding both monochromatic neutrinos as well as antineutrinos, are discussed. A sensitivity in the mixing angle theta14, (sin(2\theta14))^2=0.1 (99 %), can be reached after a few months of data handling.
1508.02532
Tomas Kasemets
Tomas Kasemets
Transverse Momentum Dependent (Un)polarized Gluon Distributions in Higgs Production
7 pages, 2 figures, To appear in the proceedings of DIS 2015
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We combine soft and collinear matrix elements to define transverse momentum dependent parton distributions (TMDs) for gluons, free from rapidity divergences. We establish a factorization theorem at next-to-leading order for the Higgs boson transverse momentum ($q_T$) spectrum, and use it to derive evolution equations for gluon TMDs. The evolution for all gluon TMDs is driven by a universal kernel, i.e. the same for all polarizations. In the region of intermediate $q_T$ we match the unpolarized, helicity and linearly polarized gluon distributions onto PDFs. We calculate the resummed Higgs transverse momentum distribution at NNLL, including the contribution of the linearly polarized gluons, and investigate the impact of non-perturbative models for the transverse distribution of gluons inside the proton.
[ { "created": "Tue, 11 Aug 2015 09:30:35 GMT", "version": "v1" } ]
2015-08-12
[ [ "Kasemets", "Tomas", "" ] ]
We combine soft and collinear matrix elements to define transverse momentum dependent parton distributions (TMDs) for gluons, free from rapidity divergences. We establish a factorization theorem at next-to-leading order for the Higgs boson transverse momentum ($q_T$) spectrum, and use it to derive evolution equations for gluon TMDs. The evolution for all gluon TMDs is driven by a universal kernel, i.e. the same for all polarizations. In the region of intermediate $q_T$ we match the unpolarized, helicity and linearly polarized gluon distributions onto PDFs. We calculate the resummed Higgs transverse momentum distribution at NNLL, including the contribution of the linearly polarized gluons, and investigate the impact of non-perturbative models for the transverse distribution of gluons inside the proton.
hep-ph/9706379
Theory Group Member
S.Y. Choi, C.S. Kim and Jake Lee (Dept. of Physics, Yonsei Univ.)
T-odd Gluon-Top-Quark Effective Couplings at the CERN Large Hadron Collider
14 pages(LaTeX), 1 Postscript figure(use epsfig.sty)
Phys.Lett. B415 (1997) 67-74
10.1016/S0370-2693(97)01238-0
YUMS 97-16, SNUTP 97-081
hep-ph
null
The T-odd top-quark chromoelectric dipole moment (tCEDM) is probed through top-quark-pair production via gluon fusion at the CERN Large Hadron Collider (LHC) by considering the possibility of having polarized protons. The complete analytic expressions for the tree-level helicity amplitudes of gg-> ttbar is also presented. For the derived analytic results we determine the 1-sigma statistical sensitivities to the tCEDM form factor for (i) typical CP-odd observables composed of lepton and anti-lepton momenta from t and tbar semileptonic decays for unpolarized protons, and (ii) a CP-odd event asymmetry for polarized protons by using the so-called Berger-Qiu (BQ) parametrization of polarized gluon distribution functions. We find that at the CERN LHC, the CP-odd energy and angular correlations can put a limit of 10^{-18} to 10^{-17} g_scm on the real and imaginary parts of the tCEDM, while the simple CP-odd event asymmetry with polarized protons could put a very strong limit of 10^{-20} g_scm on the imaginary part of the tCEDM.
[ { "created": "Tue, 17 Jun 1997 05:05:45 GMT", "version": "v1" } ]
2009-10-30
[ [ "Choi", "S. Y.", "", "Dept. of Physics, Yonsei Univ." ], [ "Kim", "C. S.", "", "Dept. of Physics, Yonsei Univ." ], [ "Lee", "Jake", "", "Dept. of Physics, Yonsei Univ." ] ]
The T-odd top-quark chromoelectric dipole moment (tCEDM) is probed through top-quark-pair production via gluon fusion at the CERN Large Hadron Collider (LHC) by considering the possibility of having polarized protons. The complete analytic expressions for the tree-level helicity amplitudes of gg-> ttbar is also presented. For the derived analytic results we determine the 1-sigma statistical sensitivities to the tCEDM form factor for (i) typical CP-odd observables composed of lepton and anti-lepton momenta from t and tbar semileptonic decays for unpolarized protons, and (ii) a CP-odd event asymmetry for polarized protons by using the so-called Berger-Qiu (BQ) parametrization of polarized gluon distribution functions. We find that at the CERN LHC, the CP-odd energy and angular correlations can put a limit of 10^{-18} to 10^{-17} g_scm on the real and imaginary parts of the tCEDM, while the simple CP-odd event asymmetry with polarized protons could put a very strong limit of 10^{-20} g_scm on the imaginary part of the tCEDM.
2311.13175
Hong Mao
Junrong Wang, Jinshuang Jin and Hong Mao
Bubble dynamics in the Polyakov quark-meson model
23 pages, 12 figures, the revised version is to be published in Symmetry
Symmetry 2024, 16, 893
10.3390/sym16070893
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
In the framework of the Polyakov quark-meson model with two flavors, the bubble dynamics of a first-order phase transition in the region of high density and low temperature are investigated by using the homogeneous thermal nucleation theory. In mean-field approximation, after obtaining the effective potential with inclusion of the fermionic vacuum term, we build a geometric method to search two existing minima, which can be actually connected by a bounce interpolated between a local minimum to an adjacent global one. For both weak and strong first-order hadron quark phase transitions, as fixing the chemical potentials at $\mu=306 \mathrm{MeV}$ and $\mu=310 \mathrm{MeV}$, the bubble profiles, the surface tension, the typical radius of the bounce and the saddle point action as a function of temperature are numerically calculated in the presence of a nucleation bubble. It is found that the surface tension remains a very small value even when the density is high. It is also noticed that the deconfinement phase transition does not change chiral phase transition dramatically for light quarks and phase boundaries for hadron and quark matter should be resized properly according to the saddle-point action evaluated on the bounce solution.
[ { "created": "Wed, 22 Nov 2023 05:40:01 GMT", "version": "v1" }, { "created": "Mon, 27 Nov 2023 06:00:41 GMT", "version": "v2" }, { "created": "Tue, 9 Jul 2024 07:12:08 GMT", "version": "v3" } ]
2024-07-16
[ [ "Wang", "Junrong", "" ], [ "Jin", "Jinshuang", "" ], [ "Mao", "Hong", "" ] ]
In the framework of the Polyakov quark-meson model with two flavors, the bubble dynamics of a first-order phase transition in the region of high density and low temperature are investigated by using the homogeneous thermal nucleation theory. In mean-field approximation, after obtaining the effective potential with inclusion of the fermionic vacuum term, we build a geometric method to search two existing minima, which can be actually connected by a bounce interpolated between a local minimum to an adjacent global one. For both weak and strong first-order hadron quark phase transitions, as fixing the chemical potentials at $\mu=306 \mathrm{MeV}$ and $\mu=310 \mathrm{MeV}$, the bubble profiles, the surface tension, the typical radius of the bounce and the saddle point action as a function of temperature are numerically calculated in the presence of a nucleation bubble. It is found that the surface tension remains a very small value even when the density is high. It is also noticed that the deconfinement phase transition does not change chiral phase transition dramatically for light quarks and phase boundaries for hadron and quark matter should be resized properly according to the saddle-point action evaluated on the bounce solution.
1404.2420
Mitsuru Kakizaki
Mitsuru Kakizaki
Higgs Phenomenology as a Probe of Supersymmetric Grand Unification with the Hosotani Mechanism
7 pages, 3 figures. Talk presented at the International Workshop on Future Linear Colliders (LCWS13), Tokyo, Japan, 11-15 November 2013
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In the supersymmetric SU(5) grand unified theory whose gauge symmetry is broken by virtue of the Hosotani mechanism, the huge mass splitting between the colored Higgs triplet and the electroweak Higgs doublet superfields is naturally realized. As a byproduct, the existence of adjoint chiral superfields with masses of the order of the supersymmetry breaking scale is predicted, leading to the Higgs sector that contains an SU(2)_L triplet chiral multiplet with hypercharge zero and a neutral singlet one in addition to the two SU(2)_L doublets of the minimal supersymmetric standard model. We focus on the Higgs sector and investigate to what extent the couplings of the standard model-like Higgs boson and the masses of the additional Higgs bosons deviate from those in the Standard Model and other models due to the new triplet and singlet chiral multiplets. We show that this model can be distinguished using precision measurements of couplings and masses of the Higgs sector particles and serves as a good example of grand unification testable at colliders such as the luminosity up-graded Large Hadron Collider and future electron-positron colliders.
[ { "created": "Wed, 9 Apr 2014 10:18:59 GMT", "version": "v1" } ]
2014-04-10
[ [ "Kakizaki", "Mitsuru", "" ] ]
In the supersymmetric SU(5) grand unified theory whose gauge symmetry is broken by virtue of the Hosotani mechanism, the huge mass splitting between the colored Higgs triplet and the electroweak Higgs doublet superfields is naturally realized. As a byproduct, the existence of adjoint chiral superfields with masses of the order of the supersymmetry breaking scale is predicted, leading to the Higgs sector that contains an SU(2)_L triplet chiral multiplet with hypercharge zero and a neutral singlet one in addition to the two SU(2)_L doublets of the minimal supersymmetric standard model. We focus on the Higgs sector and investigate to what extent the couplings of the standard model-like Higgs boson and the masses of the additional Higgs bosons deviate from those in the Standard Model and other models due to the new triplet and singlet chiral multiplets. We show that this model can be distinguished using precision measurements of couplings and masses of the Higgs sector particles and serves as a good example of grand unification testable at colliders such as the luminosity up-graded Large Hadron Collider and future electron-positron colliders.
hep-ph/0311347
Partha Konar
Partha Konar, Biswarup Mukhopadhyaya
Gauge boson fusion as a probe of inverted hierarchies in supersymmetry
RevTeX4, 4 pages, 2 figures. Final version to appear in Phys.Rev.D Changes in context, figures modified. References added. Conclusions unchanged
Phys.Rev. D70 (2004) 115011
10.1103/PhysRevD.70.115011
MRI-P-031102
hep-ph
null
Supersymmetric scenarios with inverted mass hierarchy can be hard to observe at a hadron collider, particularly for the non-strongly interacting sector. We show how the production of stau-pairs via gauge boson fusion, along with hard jets in the high rapidity region, can be instrumental in uncovering the signatures of such scenarios. We demonstrate this both in a model-independent way and with reference to some specific, well-motivated models.
[ { "created": "Wed, 26 Nov 2003 18:12:03 GMT", "version": "v1" }, { "created": "Mon, 6 Dec 2004 11:31:03 GMT", "version": "v2" } ]
2007-05-23
[ [ "Konar", "Partha", "" ], [ "Mukhopadhyaya", "Biswarup", "" ] ]
Supersymmetric scenarios with inverted mass hierarchy can be hard to observe at a hadron collider, particularly for the non-strongly interacting sector. We show how the production of stau-pairs via gauge boson fusion, along with hard jets in the high rapidity region, can be instrumental in uncovering the signatures of such scenarios. We demonstrate this both in a model-independent way and with reference to some specific, well-motivated models.
1612.02010
Maria Benito
Maria Benito, Nicolas Bernal, Nassim Bozorgnia, Francesca Calore and Fabio Iocco
Particle Dark Matter Constraints: the Effect of Galactic Uncertainties
Mistake in integrated baryonic masses corrected in Table 1. All other numbers and conclusions unaffected
Journal of Cosmology and Astroparticle Physics 2017(02), 007
10.1088/1475-7516/2017/02/007
null
hep-ph astro-ph.GA
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Collider, space, and Earth based experiments are now able to probe several extensions of the Standard Model of particle physics which provide viable dark matter candidates. Direct and indirect dark matter searches rely on inputs of astrophysical nature, such as the local dark matter density or the shape of the dark matter profile in the target in object. The determination of these quantities is highly affected by astrophysical uncertainties. The latter, especially those for our own Galaxy, are ill-known, and often not fully accounted for when analyzing the phenomenology of particle physics models. In this paper we present a systematic, quantitative estimate of how astrophysical uncertainties on Galactic quantities (such as the local galactocentric distance, circular velocity, or the morphology of the stellar disk and bulge) propagate to the determination of the phenomenology of particle physics models, thus eventually affecting the determination of new physics parameters. We present results in the context of two specific extensions of the Standard Model (the Singlet Scalar and the Inert Doublet) that we adopt as case studies for their simplicity in illustrating the magnitude and impact of such uncertainties on the parameter space of the particle physics model itself. Our findings point toward very relevant effects of current Galactic uncertainties on the determination of particle physics parameters, and urge a systematic estimate of such uncertainties in more complex scenarios, in order to achieve constraints on the determination of new physics that realistically include all known uncertainties.
[ { "created": "Tue, 6 Dec 2016 21:00:07 GMT", "version": "v1" }, { "created": "Wed, 2 May 2018 21:04:52 GMT", "version": "v2" } ]
2018-05-04
[ [ "Benito", "Maria", "" ], [ "Bernal", "Nicolas", "" ], [ "Bozorgnia", "Nassim", "" ], [ "Calore", "Francesca", "" ], [ "Iocco", "Fabio", "" ] ]
Collider, space, and Earth based experiments are now able to probe several extensions of the Standard Model of particle physics which provide viable dark matter candidates. Direct and indirect dark matter searches rely on inputs of astrophysical nature, such as the local dark matter density or the shape of the dark matter profile in the target in object. The determination of these quantities is highly affected by astrophysical uncertainties. The latter, especially those for our own Galaxy, are ill-known, and often not fully accounted for when analyzing the phenomenology of particle physics models. In this paper we present a systematic, quantitative estimate of how astrophysical uncertainties on Galactic quantities (such as the local galactocentric distance, circular velocity, or the morphology of the stellar disk and bulge) propagate to the determination of the phenomenology of particle physics models, thus eventually affecting the determination of new physics parameters. We present results in the context of two specific extensions of the Standard Model (the Singlet Scalar and the Inert Doublet) that we adopt as case studies for their simplicity in illustrating the magnitude and impact of such uncertainties on the parameter space of the particle physics model itself. Our findings point toward very relevant effects of current Galactic uncertainties on the determination of particle physics parameters, and urge a systematic estimate of such uncertainties in more complex scenarios, in order to achieve constraints on the determination of new physics that realistically include all known uncertainties.
1005.2601
Carlos Louren\c{c}o
Pietro Faccioli, Carlos Lourenco and Joao Seixas
Rotation-invariant relations in vector meson decays into fermion pairs
null
Phys.Rev.Lett.105:061601,2010
10.1103/PhysRevLett.105.061601
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The rotational properties of angular momentum eigenstates imply the existence of a frame-independent relation among the parameters of the decay distribution of vector mesons into fermions. This relation is a generalization of the Lam-Tung identity, a result specific to Drell-Yan production in perturbative QCD, here shown to be equivalent to the dynamical condition that the dilepton always originates from a transversely polarized photon.
[ { "created": "Fri, 14 May 2010 18:42:32 GMT", "version": "v1" } ]
2014-11-21
[ [ "Faccioli", "Pietro", "" ], [ "Lourenco", "Carlos", "" ], [ "Seixas", "Joao", "" ] ]
The rotational properties of angular momentum eigenstates imply the existence of a frame-independent relation among the parameters of the decay distribution of vector mesons into fermions. This relation is a generalization of the Lam-Tung identity, a result specific to Drell-Yan production in perturbative QCD, here shown to be equivalent to the dynamical condition that the dilepton always originates from a transversely polarized photon.
1311.2593
Dietrich Bodeker
Dietrich Bodeker and Mirco Wormann
Non-relativistic leptogenesis
19 pages, 5 figures. Presentation of the numerical results slightly rearranged to improve the line of arguments why full momentum dependent Boltzmann equation is unnecessary, one reference added, journal version
JCAP02(2014)016
10.1088/1475-7516/2014/02/016
BI-TP 2013/18
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In many phenomenologically interesting models of thermal leptogenesis the heavy neutrinos are non-relativistic when they decay and produce the baryon asymmetry of the Universe. We propose a non-relativistic approximation for the corresponding rate equations in the non-resonant case, and a systematic way for computing relativistic corrections. We determine the leading order coefficients in these equations, and the first relativistic corrections. The non-relativistic approximation works remarkably well. It appears to be consistent with results obtained using a Boltzmann equation taking into account the momentum distribution of the heavy neutrinos, while being much simpler. We also compute radiative corrections to some of the coefficients in the rate equations. Their effect is of order 1% in the regime favored by neutrino oscillation data. We obtain the correct leading order lepton number washout rate in this regime, which leads to large (~ 20%) effects compared to previous computations.
[ { "created": "Mon, 11 Nov 2013 21:00:10 GMT", "version": "v1" }, { "created": "Tue, 11 Feb 2014 15:11:27 GMT", "version": "v2" } ]
2015-06-17
[ [ "Bodeker", "Dietrich", "" ], [ "Wormann", "Mirco", "" ] ]
In many phenomenologically interesting models of thermal leptogenesis the heavy neutrinos are non-relativistic when they decay and produce the baryon asymmetry of the Universe. We propose a non-relativistic approximation for the corresponding rate equations in the non-resonant case, and a systematic way for computing relativistic corrections. We determine the leading order coefficients in these equations, and the first relativistic corrections. The non-relativistic approximation works remarkably well. It appears to be consistent with results obtained using a Boltzmann equation taking into account the momentum distribution of the heavy neutrinos, while being much simpler. We also compute radiative corrections to some of the coefficients in the rate equations. Their effect is of order 1% in the regime favored by neutrino oscillation data. We obtain the correct leading order lepton number washout rate in this regime, which leads to large (~ 20%) effects compared to previous computations.
0805.1379
Thorsten Ohl
Alexander Knochel, Thorsten Ohl (W\"urzburg University)
Supersymmetric Extensions and Dark Matter in Models of Warped Higgsless EWSB
LaTeX, 24 pages, figures included, fixed a reference, improved legibility of figures, version accepted for publication in Physical Review D
Phys.Rev.D78:045016,2008
10.1103/PhysRevD.78.045016
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We introduce a minimal supersymmetric extension of a higgsless model for electroweak symmetry breaking in a warped extra dimension. In contrast to the non supersymmetric version, our model naturally contains a candidate for cold dark matter. No KK-parity is required, because its stability is guaranteed by an R-parity. We discuss the regions in parameter that are compatible with the observed dark matter content of our universe and are allowed by electroweak precision measurements as well as direct searches.
[ { "created": "Fri, 9 May 2008 16:16:19 GMT", "version": "v1" }, { "created": "Thu, 10 Jul 2008 16:37:16 GMT", "version": "v2" } ]
2008-11-26
[ [ "Knochel", "Alexander", "", "Würzburg University" ], [ "Ohl", "Thorsten", "", "Würzburg University" ] ]
We introduce a minimal supersymmetric extension of a higgsless model for electroweak symmetry breaking in a warped extra dimension. In contrast to the non supersymmetric version, our model naturally contains a candidate for cold dark matter. No KK-parity is required, because its stability is guaranteed by an R-parity. We discuss the regions in parameter that are compatible with the observed dark matter content of our universe and are allowed by electroweak precision measurements as well as direct searches.
hep-ph/0011174
Bingsong Zou
B.S. Zou (CCAST World Laboratory and Institute of High Energy Physics, CAS, Beijing, P.R.China)
Light Hadron Spectroscopy at BEPC
Postscript file, 10 pages. Invited talk at Low Energy Antiproton Physics Conference (LEAP2000), Venice, Italy, August, 2000
Nucl.Phys. A692 (2001) 362-371
10.1016/S0375-9474(01)01199-X
null
hep-ph
null
The $J/\Psi$ and $\Psi'$ experiments at the Beijing Electron Positron Collider (BEPC) play a unique role in many aspects of light hadron spectroscopy, such as hunting for glueballs and hybrids, extracting $u\bar u+d\bar d$ and $s\bar s$ components of mesons, and studying excited nucleons and hyperons, i.e., $N^*$, $\Lambda^*$, $\Sigma^*$ and $\Xi^*$ resonances. Physics objectives, recent results and future prospects of light hadron spectroscopy at BEPC are presented.
[ { "created": "Tue, 14 Nov 2000 03:18:40 GMT", "version": "v1" } ]
2009-10-31
[ [ "Zou", "B. S.", "", "CCAST World Laboratory and Institute of High Energy Physics,\n CAS, Beijing, P.R.China" ] ]
The $J/\Psi$ and $\Psi'$ experiments at the Beijing Electron Positron Collider (BEPC) play a unique role in many aspects of light hadron spectroscopy, such as hunting for glueballs and hybrids, extracting $u\bar u+d\bar d$ and $s\bar s$ components of mesons, and studying excited nucleons and hyperons, i.e., $N^*$, $\Lambda^*$, $\Sigma^*$ and $\Xi^*$ resonances. Physics objectives, recent results and future prospects of light hadron spectroscopy at BEPC are presented.
2109.07496
Basem Mahmoud El-Menoufi
Mrinal Dasgupta and Basem Kamal El-Menoufi
Dissecting the collinear structure of quark splitting at NNLL
33 pages, 5 figures. Some typographical errors are corrected. Matches published version
null
10.1007/JHEP12(2021)158
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We explore the collinear limit of final-state quark splittings at order $\alpha_s^2$. While at general NLL level, this limit is described simply by a product of leading-order $1\to 2$ DGLAP splitting functions, at the NNLL level we need to consider $1\to3$ splitting functions. Here, by performing suitable integrals of the triple-collinear splitting functions, we demonstrate how one may extract $\mathcal{B}^q_2(z)$, a differential version of the coefficient $B^q_2$ that enters the quark form factor at NNLL and governs the intensity of collinear radiation from a quark. The variable $z$ corresponds to the quark energy fraction after an initial $1 \to 2$ splitting, and our results yield effective higher-order splitting functions, which may be considered as a step towards the construction of NNLL parton showers. Further, while in the limit $z \to 1$ we recover the standard soft limit results involving the CMW coupling with scale $k_t$, the $z$ dependence we obtain also motivates the extension of the notion of a physical coupling beyond the soft limit.
[ { "created": "Wed, 15 Sep 2021 18:00:49 GMT", "version": "v1" }, { "created": "Wed, 29 Sep 2021 17:25:38 GMT", "version": "v2" }, { "created": "Wed, 16 Feb 2022 16:25:09 GMT", "version": "v3" } ]
2022-02-17
[ [ "Dasgupta", "Mrinal", "" ], [ "El-Menoufi", "Basem Kamal", "" ] ]
We explore the collinear limit of final-state quark splittings at order $\alpha_s^2$. While at general NLL level, this limit is described simply by a product of leading-order $1\to 2$ DGLAP splitting functions, at the NNLL level we need to consider $1\to3$ splitting functions. Here, by performing suitable integrals of the triple-collinear splitting functions, we demonstrate how one may extract $\mathcal{B}^q_2(z)$, a differential version of the coefficient $B^q_2$ that enters the quark form factor at NNLL and governs the intensity of collinear radiation from a quark. The variable $z$ corresponds to the quark energy fraction after an initial $1 \to 2$ splitting, and our results yield effective higher-order splitting functions, which may be considered as a step towards the construction of NNLL parton showers. Further, while in the limit $z \to 1$ we recover the standard soft limit results involving the CMW coupling with scale $k_t$, the $z$ dependence we obtain also motivates the extension of the notion of a physical coupling beyond the soft limit.
0807.2244
Scott Watson
Gordon Kane and Scott Watson
Dark Matter and LHC: What is the Connection?
25 pages, 2 figures, Invited review for Modern Physics Letters A
Mod.Phys.Lett.A23:2103-2123,2008
10.1142/S0217732308028314
null
hep-ph astro-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We review what can (and cannot) be learned if dark matter is detected in one or more experiments, emphasizing the importance of combining LHC data with direct, astrophysical and cosmological probes of dark matter. We briefly review the conventional picture of a thermally produced WIMP relic density and its connection with theories of electroweak symmetry breaking. We then discuss both experimental and theoretical reasons why one might generically expect this picture to fail. If this is the case, we argue that a combined effort bringing together all types of data -- combined with explicitly constructed theoretical models -- will be the only way to achieve a complete understanding of the dark matter in our universe and become confident that any candidate actually provides the relic density.
[ { "created": "Mon, 14 Jul 2008 20:02:17 GMT", "version": "v1" } ]
2008-11-07
[ [ "Kane", "Gordon", "" ], [ "Watson", "Scott", "" ] ]
We review what can (and cannot) be learned if dark matter is detected in one or more experiments, emphasizing the importance of combining LHC data with direct, astrophysical and cosmological probes of dark matter. We briefly review the conventional picture of a thermally produced WIMP relic density and its connection with theories of electroweak symmetry breaking. We then discuss both experimental and theoretical reasons why one might generically expect this picture to fail. If this is the case, we argue that a combined effort bringing together all types of data -- combined with explicitly constructed theoretical models -- will be the only way to achieve a complete understanding of the dark matter in our universe and become confident that any candidate actually provides the relic density.
hep-ph/9607358
Scott A. Yost
S. Jadach, M. Melles, B. F. L. Ward and S. A. Yost
Bhabha Process at LEP - Theoretical Calculations
11 pages LaTeX, 7 Postscript figures, uses amstex. Presented by S. Jadach at Zeuthen Workshop, April 1996, Rheinsberg, Germany. Correction fixes incorrect preprint number: no change in contents
Nucl.Phys.Proc.Suppl. 51C (1996) 164-173
10.1016/S0920-5632(96)90021-3
CERN-TH/96-176, UTHEP-96-0603
hep-ph
null
In this contribution we give a short overview of the situation in the precision calculation of the Bhabha process and we present a preliminary numerical result on the second-order sub-leading correction to the small angle Bhabha process.
[ { "created": "Wed, 17 Jul 1996 18:29:09 GMT", "version": "v1" }, { "created": "Fri, 19 Jul 1996 17:33:22 GMT", "version": "v2" } ]
2015-06-25
[ [ "Jadach", "S.", "" ], [ "Melles", "M.", "" ], [ "Ward", "B. F. L.", "" ], [ "Yost", "S. A.", "" ] ]
In this contribution we give a short overview of the situation in the precision calculation of the Bhabha process and we present a preliminary numerical result on the second-order sub-leading correction to the small angle Bhabha process.
2212.05121
Jayita Lahiri
Sahabub Jahedi, Jayita Lahiri
Probing anomalous $Z\,Z\,\gamma$ and $Z\,\gamma\,\gamma$ Couplings at the $e^+\,e^-$ Colliders using Optimal Observable Technique
22 pages, 10 figures
null
10.1007/JHEP04(2023)085
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
We study the anomalous $ZZ\gamma$ and $Z\gamma\gamma$ couplings that can be probed via $Z\gamma$ production at the $e^+ \, e^-$ colliders. We take Standard Model Effective Field Theory (SMEFT) approach to examine these anomalous neutral triple gauge couplings in a model independent way. There are four independent dimension-8 operators that generate these gauge interactions, one of them is CP-conserving and rest three are CP-violating. We adopt optimal observable technique to extract the sensitivity at which these anomalous couplings can be probed at future $e^+e^-$ colliders and then compare the results with the latest experimental limit obtained at the LHC. We also study the impact and advantage of beam polarization in these precision measurements. Statistical limit (95\% C.L.) on individual anomalous couplings as well as the correlation between various couplings have been discussed in detail.
[ { "created": "Fri, 9 Dec 2022 21:28:25 GMT", "version": "v1" }, { "created": "Tue, 4 Apr 2023 14:04:40 GMT", "version": "v2" } ]
2023-05-10
[ [ "Jahedi", "Sahabub", "" ], [ "Lahiri", "Jayita", "" ] ]
We study the anomalous $ZZ\gamma$ and $Z\gamma\gamma$ couplings that can be probed via $Z\gamma$ production at the $e^+ \, e^-$ colliders. We take Standard Model Effective Field Theory (SMEFT) approach to examine these anomalous neutral triple gauge couplings in a model independent way. There are four independent dimension-8 operators that generate these gauge interactions, one of them is CP-conserving and rest three are CP-violating. We adopt optimal observable technique to extract the sensitivity at which these anomalous couplings can be probed at future $e^+e^-$ colliders and then compare the results with the latest experimental limit obtained at the LHC. We also study the impact and advantage of beam polarization in these precision measurements. Statistical limit (95\% C.L.) on individual anomalous couplings as well as the correlation between various couplings have been discussed in detail.
1806.09547
Pablo Roig
J. A. Miranda and P. Roig
Effective-field theory analysis of the $\tau^-\to \pi^-\pi^0\nu_\tau$ decays
v3: Lattice QCD determination of the tensor charge used, theoretical error of the vector form factor accounted for, a couple of improved observables for Dalitz plots and forward-backward asymmetries have been introduced. Rewording and updated references included. 23 pages, 12 figures, 1 tables, JHEP style
JHEP11(2018)038
10.1007/JHEP11(2018)038
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We perform an effective field theory analysis of the $\tau^- \to \pi^- \pi^0 \nu_\tau$ decays, that includes the most general interactions between Standard Model fields up to dimension six, assuming left-handed neutrinos. We constrain as much as possible the necessary Standard Model hadronic input using chiral symmetry, dispersion relations, data and asymptotic QCD properties. As a result, we set precise (competitive with low-energy and LHC measurements) bounds on (non-standard) charged current tensor interactions, finding a very small preference for their presence, according to Belle data. Belle-II near future measurements can thus be very useful in either confirming or further restricting new physics tensor current contributions to these decays. For this, the spectrum in the di-pion invariant mass turns out to be particularly promising. Distributions in the angle defined by the $\tau^-$ and $\pi^-$ momenta can also be helpful if measured with less than $10\%$ accuracy, both for non-standard scalar and tensor interactions.
[ { "created": "Mon, 25 Jun 2018 16:12:24 GMT", "version": "v1" }, { "created": "Mon, 2 Jul 2018 15:01:34 GMT", "version": "v2" }, { "created": "Thu, 20 Sep 2018 21:43:11 GMT", "version": "v3" } ]
2018-11-08
[ [ "Miranda", "J. A.", "" ], [ "Roig", "P.", "" ] ]
We perform an effective field theory analysis of the $\tau^- \to \pi^- \pi^0 \nu_\tau$ decays, that includes the most general interactions between Standard Model fields up to dimension six, assuming left-handed neutrinos. We constrain as much as possible the necessary Standard Model hadronic input using chiral symmetry, dispersion relations, data and asymptotic QCD properties. As a result, we set precise (competitive with low-energy and LHC measurements) bounds on (non-standard) charged current tensor interactions, finding a very small preference for their presence, according to Belle data. Belle-II near future measurements can thus be very useful in either confirming or further restricting new physics tensor current contributions to these decays. For this, the spectrum in the di-pion invariant mass turns out to be particularly promising. Distributions in the angle defined by the $\tau^-$ and $\pi^-$ momenta can also be helpful if measured with less than $10\%$ accuracy, both for non-standard scalar and tensor interactions.
0908.0342
Reinard Primulando
Christopher D. Carone, Reinard Primulando
Constraints on the Lee-Wick Higgs Sector
23 pages LaTeX, 14 figures
Phys.Rev.D80:055020,2009
10.1103/PhysRevD.80.055020
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Lee-Wick partners to the Standard Model Higgs doublet may appear at a mass scale that is significantly lower than that of the remaining Lee-Wick partner states. The relevant effective theory is a two-Higgs doublet model in which one doublet has wrong-sign kinetic and mass terms. We determine bounds on this effective theory, including those from neutral B-meson mixing, b --> X_s gamma, and Z --> b b-bar. The results differ from those of conventional two-Higgs doublet models and lead to meaningful constraints on the Lee-Wick Higgs sector.
[ { "created": "Mon, 3 Aug 2009 20:47:17 GMT", "version": "v1" } ]
2009-12-10
[ [ "Carone", "Christopher D.", "" ], [ "Primulando", "Reinard", "" ] ]
Lee-Wick partners to the Standard Model Higgs doublet may appear at a mass scale that is significantly lower than that of the remaining Lee-Wick partner states. The relevant effective theory is a two-Higgs doublet model in which one doublet has wrong-sign kinetic and mass terms. We determine bounds on this effective theory, including those from neutral B-meson mixing, b --> X_s gamma, and Z --> b b-bar. The results differ from those of conventional two-Higgs doublet models and lead to meaningful constraints on the Lee-Wick Higgs sector.
1801.03256
Shakeel Ahmad Professor
Shaista Khan and Shakeel Ahmad
Multifractal Characteristics of Multiparticle Production in Heavy-Ion Collisions at SPS Energies
null
International Journal of Modern Physics E Vol. 27, No. 1 (2018) 1850004
10.1142/S0218301318500040
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Entropy, dimensions and other multifractal characteristics of multiplicity distributions of relativistic charged hadrons produced in ion-ion collisions at SPS energies are investigated. The analysis of the experimental data is carried out in terms of phase space bin-size dependence of multiplicity distributions following the Takagi's approach. Yet another method is also followed to study the multifractality which, is not related to the bin-width and (or) the detector resolution, rather involves multiplicity distribution of charged particles in full phase space in terms of information entropy and its generalization, R\'{e}nyi's order-q information entropy. The findings reveal the presence of multifractal structure-- a remarkable property of the fluctuations. Nearly constant values of multifractal specific heat, 'c' estimated by the two different methods of analysis followed indicate that the parameter 'c' may be used as a universal characteristic of the particle production in high energy collisions. The results obtained from the analysis of the experimental data agree well with the predictions of Monte Carlo model AMPT.
[ { "created": "Wed, 10 Jan 2018 07:48:53 GMT", "version": "v1" } ]
2018-01-11
[ [ "Khan", "Shaista", "" ], [ "Ahmad", "Shakeel", "" ] ]
Entropy, dimensions and other multifractal characteristics of multiplicity distributions of relativistic charged hadrons produced in ion-ion collisions at SPS energies are investigated. The analysis of the experimental data is carried out in terms of phase space bin-size dependence of multiplicity distributions following the Takagi's approach. Yet another method is also followed to study the multifractality which, is not related to the bin-width and (or) the detector resolution, rather involves multiplicity distribution of charged particles in full phase space in terms of information entropy and its generalization, R\'{e}nyi's order-q information entropy. The findings reveal the presence of multifractal structure-- a remarkable property of the fluctuations. Nearly constant values of multifractal specific heat, 'c' estimated by the two different methods of analysis followed indicate that the parameter 'c' may be used as a universal characteristic of the particle production in high energy collisions. The results obtained from the analysis of the experimental data agree well with the predictions of Monte Carlo model AMPT.
1910.02091
Felix Kahlhoefer
R. Matthias Geilhufe, Felix Kahlhoefer and Martin Wolfgang Winkler
Dirac Materials for Sub-MeV Dark Matter Detection: New Targets and Improved Formalism
21 pages, 9 figures + appendix; v2: matches published version
Phys. Rev. D 101, 055005 (2020)
10.1103/PhysRevD.101.055005
TTK-19-42
hep-ph cond-mat.mtrl-sci hep-ex
http://creativecommons.org/licenses/by/4.0/
Because of their tiny band gaps Dirac materials promise to improve the sensitivity for dark matter particles in the sub-MeV mass range by many orders of magnitude. Here we study several candidate materials and calculate the expected rates for dark matter scattering via light and heavy dark photons as well as for dark photon absorption. A particular emphasis is placed on how to distinguish a dark matter signal from background by searching for the characteristic daily modulation of the signal, which arises from the directional sensitivity of anisotropic materials in combination with the rotation of the Earth. We revisit and improve previous calculations and propose two new candidate Dirac materials: BNQ-TTF and Yb$_3$PbO. We perform detailed calculations of the band structures of these materials and of ZrTe$_5$ based on density functional theory and determine the band gap, the Fermi velocities and the dielectric tensor. We show that in both ZrTe$_5$ and BNQ-TTF the amplitude of the daily modulation can be larger than 10% of the total rate, allowing to probe the preferred regions of parameter space even in the presence of sizeable backgrounds. BNQ-TTF is found to be particularly sensitive to small dark matter masses (below 100 keV for scattering and below 50 meV for absorption), while Yb$_3$PbO performs best for heavier particles.
[ { "created": "Fri, 4 Oct 2019 18:05:10 GMT", "version": "v1" }, { "created": "Thu, 27 Feb 2020 07:06:50 GMT", "version": "v2" } ]
2020-03-11
[ [ "Geilhufe", "R. Matthias", "" ], [ "Kahlhoefer", "Felix", "" ], [ "Winkler", "Martin Wolfgang", "" ] ]
Because of their tiny band gaps Dirac materials promise to improve the sensitivity for dark matter particles in the sub-MeV mass range by many orders of magnitude. Here we study several candidate materials and calculate the expected rates for dark matter scattering via light and heavy dark photons as well as for dark photon absorption. A particular emphasis is placed on how to distinguish a dark matter signal from background by searching for the characteristic daily modulation of the signal, which arises from the directional sensitivity of anisotropic materials in combination with the rotation of the Earth. We revisit and improve previous calculations and propose two new candidate Dirac materials: BNQ-TTF and Yb$_3$PbO. We perform detailed calculations of the band structures of these materials and of ZrTe$_5$ based on density functional theory and determine the band gap, the Fermi velocities and the dielectric tensor. We show that in both ZrTe$_5$ and BNQ-TTF the amplitude of the daily modulation can be larger than 10% of the total rate, allowing to probe the preferred regions of parameter space even in the presence of sizeable backgrounds. BNQ-TTF is found to be particularly sensitive to small dark matter masses (below 100 keV for scattering and below 50 meV for absorption), while Yb$_3$PbO performs best for heavier particles.
hep-ph/9902264
Yang Ji-feng
Jifeng Yang(Fudan Univ., Shanghai, P. R. China)
On the utility and implication of convex effective potential for the Higgs particles
10 pages, LaTex, no figure, revised version
null
null
null
hep-ph hep-th
null
It is suggested that within the effective potential approach, convexity and spontaneous symmetry breaking(SSB) make the Higgs modes (elementary or effective) complicated in that the normal final states (experimentally identifiable) for Higgs modes could not be analytically defined. This observation might have some nontrivial consequences for the Standard Model (SM) and particle physics.
[ { "created": "Mon, 8 Feb 1999 08:14:39 GMT", "version": "v1" }, { "created": "Mon, 22 Mar 1999 03:10:48 GMT", "version": "v2" }, { "created": "Wed, 2 Jun 1999 02:49:31 GMT", "version": "v3" } ]
2007-05-23
[ [ "Yang", "Jifeng", "", "Fudan Univ., Shanghai, P. R. China" ] ]
It is suggested that within the effective potential approach, convexity and spontaneous symmetry breaking(SSB) make the Higgs modes (elementary or effective) complicated in that the normal final states (experimentally identifiable) for Higgs modes could not be analytically defined. This observation might have some nontrivial consequences for the Standard Model (SM) and particle physics.
1510.02117
Abdel Nasser Tawfik
Abdel Nasser Tawfik (Egyptian Ctr. Theor. Phys., Cairo, WLCAPP, Cairo), Hayam Yassin, Eman R. Abo Elyazeed (Ain Shams U., Cairo)
Chemical freeze-out in Hawking-Unruh radiation and quark-hadron transition
18 pages, 2 eps-figures, to appear in PRD
Phys. Rev. D 92, (2015) 085002
10.1103/PhysRevD.92.085002
ECTP-2015-03, WLCAPP-2015-03
hep-ph gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The proposed analogy between hadron production in high-energy collisions and Hawking-Unruh radiation process in the black holes shall be extended. This mechanism provides a theoretical basis for the freeze-out parameters, the temperature ($T$) and the baryon chemical potential ($\mu$), characterizing the final state of particle production. The results from charged black holes, in which the electric charge is related to $\mu$, are found comparable with the phenomenologically deduced parameters from the ratios of various particle species and the higher-order moments of net-proton multiplicity in thermal statistical models and Polyakov linear-sigma model. Furthermore, the resulting freeze-out condition $\langle E\rangle/\langle N\rangle\simeq 1~$GeV for average energy per particle is in good agreement with the hadronization process in the high-energy experiments. For the entropy density ($s$), the freeze-out condition $s/T^3\simeq7$ remains valid for $\mu\lesssim 0.3~$GeV. Then, due to the dependence of $T$ on $\mu$, the values of $s/T^3$ increase with increasing $\mu$. In accordance with this observation, we found that the entropy density remains constant with increasing $\mu$. Thus, we conclude that almost no information is going lost through Hawking-Unruh radiation from charged black holes. It is worthwhile to highlight that the freeze-out temperature from charged black holes is determined independent on both freeze-out conditions
[ { "created": "Wed, 30 Sep 2015 20:33:59 GMT", "version": "v1" } ]
2015-10-12
[ [ "Tawfik", "Abdel Nasser", "", "Egyptian Ctr. Theor. Phys., Cairo, WLCAPP,\n Cairo" ], [ "Yassin", "Hayam", "", "Ain Shams U., Cairo" ], [ "Elyazeed", "Eman R. Abo", "", "Ain Shams U., Cairo" ] ]
The proposed analogy between hadron production in high-energy collisions and Hawking-Unruh radiation process in the black holes shall be extended. This mechanism provides a theoretical basis for the freeze-out parameters, the temperature ($T$) and the baryon chemical potential ($\mu$), characterizing the final state of particle production. The results from charged black holes, in which the electric charge is related to $\mu$, are found comparable with the phenomenologically deduced parameters from the ratios of various particle species and the higher-order moments of net-proton multiplicity in thermal statistical models and Polyakov linear-sigma model. Furthermore, the resulting freeze-out condition $\langle E\rangle/\langle N\rangle\simeq 1~$GeV for average energy per particle is in good agreement with the hadronization process in the high-energy experiments. For the entropy density ($s$), the freeze-out condition $s/T^3\simeq7$ remains valid for $\mu\lesssim 0.3~$GeV. Then, due to the dependence of $T$ on $\mu$, the values of $s/T^3$ increase with increasing $\mu$. In accordance with this observation, we found that the entropy density remains constant with increasing $\mu$. Thus, we conclude that almost no information is going lost through Hawking-Unruh radiation from charged black holes. It is worthwhile to highlight that the freeze-out temperature from charged black holes is determined independent on both freeze-out conditions
1704.08557
Luca Mantovani
C\'edric Lorc\'e, Luca Mantovani, Barbara Pasquini
Spatial distribution of angular momentum inside the nucleon
null
Phys. Lett. B776, 38 (2018)
10.1016/j.physletb.2017.11.018
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We discuss in detail the spatial distribution of angular momentum inside the nucleon. We show that the discrepancies between different definitions originate from terms that integrate to zero. Even though these terms can safely be dropped at the integrated level, they have to be taken into account at the density level. Using the scalar diquark model, we illustrate our results and, for the first time, check explicitly that the equivalence between kinetic and canonical orbital angular momentum persists at the density level, as expected in a system without gauge degrees of freedom.
[ { "created": "Thu, 27 Apr 2017 13:27:35 GMT", "version": "v1" } ]
2017-11-22
[ [ "Lorcé", "Cédric", "" ], [ "Mantovani", "Luca", "" ], [ "Pasquini", "Barbara", "" ] ]
We discuss in detail the spatial distribution of angular momentum inside the nucleon. We show that the discrepancies between different definitions originate from terms that integrate to zero. Even though these terms can safely be dropped at the integrated level, they have to be taken into account at the density level. Using the scalar diquark model, we illustrate our results and, for the first time, check explicitly that the equivalence between kinetic and canonical orbital angular momentum persists at the density level, as expected in a system without gauge degrees of freedom.
1004.4218
Nathaniel Craig
Nathaniel Craig
Simple Models of Superconformal Flavor
30 pages, 1 figure, references added
null
null
SU-ITP-10-16
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The observed hierarchy of fermion masses and mixings may be generated by renormalization group flow if the Standard Model is coupled to a near-conformal sector at high energies. If the conformal sector is supersymmetric, these effects are rendered calculable by a combination of superconformal symmetry and a-maximization. The viability of such models depends on whether they generate the observed fermion mass hierarchy before the Standard Model gauge couplings hit a Landau pole. Here we construct a variety of simple vector-like models of superconformal flavor, including both ten-centered and democratic variations. We discuss in detail the subtleties of applying the a-maximization procedure to determine anomalous dimensions of Standard Model fields. We find that a wide range of models based on SU(N) or Sp(2N) SQCD with fundamental and adjoint matter are viable theories of superconformal flavor.
[ { "created": "Fri, 23 Apr 2010 20:20:17 GMT", "version": "v1" }, { "created": "Tue, 13 Jul 2010 10:13:20 GMT", "version": "v2" } ]
2010-07-14
[ [ "Craig", "Nathaniel", "" ] ]
The observed hierarchy of fermion masses and mixings may be generated by renormalization group flow if the Standard Model is coupled to a near-conformal sector at high energies. If the conformal sector is supersymmetric, these effects are rendered calculable by a combination of superconformal symmetry and a-maximization. The viability of such models depends on whether they generate the observed fermion mass hierarchy before the Standard Model gauge couplings hit a Landau pole. Here we construct a variety of simple vector-like models of superconformal flavor, including both ten-centered and democratic variations. We discuss in detail the subtleties of applying the a-maximization procedure to determine anomalous dimensions of Standard Model fields. We find that a wide range of models based on SU(N) or Sp(2N) SQCD with fundamental and adjoint matter are viable theories of superconformal flavor.
hep-ph/0610251
Antonio Vairo
Antonio Vairo
Heavy Quarkonium Physics from Effective Field Theories
Plenary talk at the 4th International Conference on Quarks and Nuclear Physics (QNP06), 5-10 June 2006, Madrid, Spain; 6 pages, 1 figure, EPJ style
Eur.Phys.J.A31:728,2007
10.1140/epja/i2006-10200-0
IFUM-878-FT
hep-ph hep-lat nucl-th
null
I review recent progress in heavy quarkonium physics from an effective field theory perspective. In this unifying framework, I discuss advances in perturbative calculations for low-lying quarkonium observables and in lattice calculations for high-lying ones, and progress and lasting puzzles in quarkonium production.
[ { "created": "Thu, 19 Oct 2006 16:09:03 GMT", "version": "v1" } ]
2008-11-26
[ [ "Vairo", "Antonio", "" ] ]
I review recent progress in heavy quarkonium physics from an effective field theory perspective. In this unifying framework, I discuss advances in perturbative calculations for low-lying quarkonium observables and in lattice calculations for high-lying ones, and progress and lasting puzzles in quarkonium production.
hep-ph/0112332
Alexander Dorokhov
A.E. Dorokhov (JINR, Dubna)
Spin effects within the instanton model
11 pages, LaTeX file
Czech.J.Phys.52:C79-C89,2002
10.1007/s10582-002-0098-9
null
hep-ph
null
Nonperturbative nolocal structure of QCD vacuum is well described by instanton model. Specific helicity and flavor structure of zero modes of quarks in instanton field allows simultaneously to explain some important features of low- and high- energy hadron phenomemology. The basic characteristics of hadron spectrum, partonic sum rules, heavy-quark potential are briefly discussed within the instanton liquid model.
[ { "created": "Wed, 26 Dec 2001 17:19:12 GMT", "version": "v1" } ]
2009-11-07
[ [ "Dorokhov", "A. E.", "", "JINR, Dubna" ] ]
Nonperturbative nolocal structure of QCD vacuum is well described by instanton model. Specific helicity and flavor structure of zero modes of quarks in instanton field allows simultaneously to explain some important features of low- and high- energy hadron phenomemology. The basic characteristics of hadron spectrum, partonic sum rules, heavy-quark potential are briefly discussed within the instanton liquid model.
hep-ph/0205285
Romeyer Alain
Alain Romeyer
Antares Sensitivity to Diffuse High Energy Neutrino Fluxes
2 pages ElectroWeak Interactions and Unified Theories, 2002 Rencontres de Moriond
null
null
null
hep-ph
null
The European collaboration ANTARES aims at operating a large deep-sea neutrino telescope in the Mediterranean sea. The detection of high-energy cosmic neutrino can improve our knowledge on the most powerful astrophysical sources in the Universe and about the origins of cosmic rays. A first Monte-Carlo study for the ANTARES sensitivity to diffuse neutrino fluxes predicted by current models is reported.
[ { "created": "Fri, 24 May 2002 18:14:54 GMT", "version": "v1" } ]
2007-05-23
[ [ "Romeyer", "Alain", "" ] ]
The European collaboration ANTARES aims at operating a large deep-sea neutrino telescope in the Mediterranean sea. The detection of high-energy cosmic neutrino can improve our knowledge on the most powerful astrophysical sources in the Universe and about the origins of cosmic rays. A first Monte-Carlo study for the ANTARES sensitivity to diffuse neutrino fluxes predicted by current models is reported.
1402.1606
Mikhail Braun
M.A.Braun
Double inclusive cross-sections for gluon production in collision of two projectiles on two targets in the BFKL approach
arXiv admin note: substantial text overlap with arXiv:1305.1712
null
10.1140/epjc/s10052-014-2877-4
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Double inclusive cross-sections for gluon production in collision of two nucleons with two nucleons are studied in the BFKL approach. Various contributions include emission from the pomerons attached to the participants, from the BFKL interactions between these pomerons and from the intermediate BKP state. The last contribution may be observable provided the growth with energy of the pomeron contribution is tamed in accordance with unitarity. Possibility of long-range azimuthal correlations due to the BKP state are discussed.
[ { "created": "Fri, 7 Feb 2014 11:25:42 GMT", "version": "v1" }, { "created": "Fri, 7 Mar 2014 04:25:07 GMT", "version": "v2" }, { "created": "Wed, 19 Mar 2014 05:06:35 GMT", "version": "v3" } ]
2015-06-18
[ [ "Braun", "M. A.", "" ] ]
Double inclusive cross-sections for gluon production in collision of two nucleons with two nucleons are studied in the BFKL approach. Various contributions include emission from the pomerons attached to the participants, from the BFKL interactions between these pomerons and from the intermediate BKP state. The last contribution may be observable provided the growth with energy of the pomeron contribution is tamed in accordance with unitarity. Possibility of long-range azimuthal correlations due to the BKP state are discussed.
2008.04161
Antonio Palazzo
Sabya Sachi Chatterjee and Antonio Palazzo
Non-standard neutrino interactions as a solution to the NO$\nu$A and T2K discrepancy
9 pages, 6 figures, 1 table. Accepted for publication in PRL. One additional figure (S1) is presented in the Supplemental Material in addition to the PRL version
Phys. Rev. Lett. 126, 051802 (2021)
10.1103/PhysRevLett.126.051802
IPPP/20/35
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The latest data of the two long-baseline accelerator experiments NO$\nu$A and T2K, interpreted in the standard 3-flavor scenario, display a discrepancy. A mismatch in the determination of the standard CP-phase $\delta_{\mathrm {CP}}$ extracted by the two experiments is evident in the normal neutrino mass ordering. While NO$\nu$A prefers values close to $\delta_{\mathrm {CP}} \sim 0.8 \pi$, T2K identifies values of $\delta_{\mathrm {CP}} \sim 1.4 \pi$. Such two estimates are in disagreement at more than 90$\%$ C.L. for 2 degrees of freedom. We show that such a tension can be resolved if one hypothesizes the existence of complex neutral-current non-standard interactions (NSI) of the flavor changing type involving the $e-\mu$ or the $e-\tau$ sectors with couplings $|\varepsilon_{e\mu}| \sim |\varepsilon_{e\tau}|\sim 0.2$. Remarkably, in the presence of such NSI, both experiments point towards the same common value of the standard CP-phase $\delta_{\mathrm {CP}} \sim 3\pi/2$. Our analysis also highlights an intriguing preference for maximal CP-violation in the non-standard sector with the NSI CP-phases having best fit close to $\phi_{e\mu} \sim \phi_{e\tau}\sim 3\pi/2$, hence pointing towards imaginary NSI couplings.
[ { "created": "Mon, 10 Aug 2020 14:36:01 GMT", "version": "v1" }, { "created": "Wed, 13 Jan 2021 15:21:12 GMT", "version": "v2" } ]
2021-02-10
[ [ "Chatterjee", "Sabya Sachi", "" ], [ "Palazzo", "Antonio", "" ] ]
The latest data of the two long-baseline accelerator experiments NO$\nu$A and T2K, interpreted in the standard 3-flavor scenario, display a discrepancy. A mismatch in the determination of the standard CP-phase $\delta_{\mathrm {CP}}$ extracted by the two experiments is evident in the normal neutrino mass ordering. While NO$\nu$A prefers values close to $\delta_{\mathrm {CP}} \sim 0.8 \pi$, T2K identifies values of $\delta_{\mathrm {CP}} \sim 1.4 \pi$. Such two estimates are in disagreement at more than 90$\%$ C.L. for 2 degrees of freedom. We show that such a tension can be resolved if one hypothesizes the existence of complex neutral-current non-standard interactions (NSI) of the flavor changing type involving the $e-\mu$ or the $e-\tau$ sectors with couplings $|\varepsilon_{e\mu}| \sim |\varepsilon_{e\tau}|\sim 0.2$. Remarkably, in the presence of such NSI, both experiments point towards the same common value of the standard CP-phase $\delta_{\mathrm {CP}} \sim 3\pi/2$. Our analysis also highlights an intriguing preference for maximal CP-violation in the non-standard sector with the NSI CP-phases having best fit close to $\phi_{e\mu} \sim \phi_{e\tau}\sim 3\pi/2$, hence pointing towards imaginary NSI couplings.
2305.05207
Igor Ivanov
Jiazhen Shao, Igor P. Ivanov
Symmetries for the 4HDM: extensions of cyclic groups
v2: 36 pages, 2 tables, additional clarifications, matches the published version
JHEP 10 (2023) 070
10.1007/JHEP10(2023)070
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Multi-Higgs models equipped with global symmetry groups, either exact or softly broken, offer a rich framework for constructions beyond the Standard Model and lead to remarkable phenomenological consequences. Knowing all the symmetry options within each class of models can guide its phenomenological exploration, as confirmed by the vast literature on the two- and three-Higgs-doublet models. Here, we begin a systematic study of finite non-abelian symmetry groups which can be imposed on the scalar sector of the four-Higgs-doublet model (4HDM) without leading to accidental symmetries. In this work, we derive the full list of such non-abelian groups available in the 4HDM that can be constructed as extensions of cyclic groups by their automorphism groups. This list is remarkably restricted but it contains cases which have not been previously studied. Since the methods we develop may prove useful for other classes of models, we present them in a pedagogical manner.
[ { "created": "Tue, 9 May 2023 07:00:02 GMT", "version": "v1" }, { "created": "Mon, 16 Oct 2023 02:18:36 GMT", "version": "v2" } ]
2023-10-17
[ [ "Shao", "Jiazhen", "" ], [ "Ivanov", "Igor P.", "" ] ]
Multi-Higgs models equipped with global symmetry groups, either exact or softly broken, offer a rich framework for constructions beyond the Standard Model and lead to remarkable phenomenological consequences. Knowing all the symmetry options within each class of models can guide its phenomenological exploration, as confirmed by the vast literature on the two- and three-Higgs-doublet models. Here, we begin a systematic study of finite non-abelian symmetry groups which can be imposed on the scalar sector of the four-Higgs-doublet model (4HDM) without leading to accidental symmetries. In this work, we derive the full list of such non-abelian groups available in the 4HDM that can be constructed as extensions of cyclic groups by their automorphism groups. This list is remarkably restricted but it contains cases which have not been previously studied. Since the methods we develop may prove useful for other classes of models, we present them in a pedagogical manner.
1803.10514
Kouji Kashiwa
Toshitaka Tatsumi, Ryo Yoshiike, Kouji Kashiwa
Anomalous Hall effect in dense QCD matter
5 pages, 2 figures
null
10.1016/j.physletb.2018.08.023
KUNS-2719, YITP-18-20
hep-ph cond-mat.mes-hall hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this letter, we investigate the anomalous Hall effect in dense QCD matter. When the dual chiral density wave which is the spatially modulated chiral condensate appears in the medium, it gives rise to two Weyl points to the single-particle energy-spectrum and then the anomalous Hall conductivity becomes nonzero. Then, dense QCD matter is analogous to the Weyl semimetal. The direct calculation of the Hall conductivity by way of Kubo's linear response theory gives the term proportional to the distance between the Weyl points. Unlike the Weyl semimetal, there appears the additional contribution induced by axial anomaly.
[ { "created": "Wed, 28 Mar 2018 10:37:57 GMT", "version": "v1" } ]
2018-09-26
[ [ "Tatsumi", "Toshitaka", "" ], [ "Yoshiike", "Ryo", "" ], [ "Kashiwa", "Kouji", "" ] ]
In this letter, we investigate the anomalous Hall effect in dense QCD matter. When the dual chiral density wave which is the spatially modulated chiral condensate appears in the medium, it gives rise to two Weyl points to the single-particle energy-spectrum and then the anomalous Hall conductivity becomes nonzero. Then, dense QCD matter is analogous to the Weyl semimetal. The direct calculation of the Hall conductivity by way of Kubo's linear response theory gives the term proportional to the distance between the Weyl points. Unlike the Weyl semimetal, there appears the additional contribution induced by axial anomaly.
hep-ph/0508148
Shrihari Gopalakrishna
Andre de Gouvea and Shrihari Gopalakrishna
Low-Energy Neutrino Majorana Phases and Charged-Lepton Electric Dipole Moments
13 pages, 9 figures
Phys.Rev. D72 (2005) 093008
10.1103/PhysRevD.72.093008
null
hep-ph
null
If the neutrinos are Majorana fermions, there are at least three new, potentially observable CP-odd phases that parameterize CP-invariance violating phenomena. We currently have no information regarding any of them and know that two out of the three, the so-called Majorana phases, are very hard to access experimentally. Here, we discuss the effect of Majorana phases on charged-lepton electric dipole moments (EDM), and explicitly show that neutrino Majorana phases induce EDMs even in the absence of other sources of CP-invariance violation. We also argue that while the Majorana neutrino contribution to EDMs is tiny, there is one generic ultraviolet completion to the standard model plus massive Majorana neutrinos -- the standard model plus a triplet Higgs boson -- that leads to significantly enhanced contributions which are still proportional to the low-energy neutrino Majorana phases. If this particular scenario is realized in nature, it seems possible, at least in principle, to measure the Majorana phases by precisely measuring charged-lepton EDMs.
[ { "created": "Fri, 12 Aug 2005 16:59:38 GMT", "version": "v1" } ]
2009-11-11
[ [ "de Gouvea", "Andre", "" ], [ "Gopalakrishna", "Shrihari", "" ] ]
If the neutrinos are Majorana fermions, there are at least three new, potentially observable CP-odd phases that parameterize CP-invariance violating phenomena. We currently have no information regarding any of them and know that two out of the three, the so-called Majorana phases, are very hard to access experimentally. Here, we discuss the effect of Majorana phases on charged-lepton electric dipole moments (EDM), and explicitly show that neutrino Majorana phases induce EDMs even in the absence of other sources of CP-invariance violation. We also argue that while the Majorana neutrino contribution to EDMs is tiny, there is one generic ultraviolet completion to the standard model plus massive Majorana neutrinos -- the standard model plus a triplet Higgs boson -- that leads to significantly enhanced contributions which are still proportional to the low-energy neutrino Majorana phases. If this particular scenario is realized in nature, it seems possible, at least in principle, to measure the Majorana phases by precisely measuring charged-lepton EDMs.
1306.3117
Chris Wymant
Chris Wymant
Signs of Susy
Doctoral thesis, 86 pages + preamble + appendices + references, 28 figures. This article draws heavily from arXiv:1102.1589, arXiv:1103.1843, arXiv:1111.3365, arXiv:1203.3446, arXiv:1208.1737 and arXiv:1301.0345
null
null
IPPP/13/43; DCPT/13/86
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This doctoral thesis addresses aspects of Supersymmetry (Susy) phenomenology. In addition to previously published work, it contains introductions to the following topics: from classical mechanics to quantum field theory for the more casual reader, electroweak naturalness, the Higgs as a pseudo-Nambu-Goldstone boson, the MSSM and NMSSM, simple and less simple models of gauge-mediated Susy breaking (GMSB), collider searches for Susy and other new theories, transverse mass observables with missing energy, and Brazil-band plots. The previously published work is as follows. The optimally natural Higgs-stop sector in the MSSM in light of the 2012 discovery of a Higgs boson is derived, namely that of almost maximal mixing, with the scalar top partners almost as light as can be. The discovery is also interpreted numerically in the NMSSM, with greater emphasis placed on the visibility of the Higgs boson at the observed mass, i.e. on signal strengths. I investigate the role played by the mediation scale of GMSB: this is found to be as a control of the extent to which Yukawa couplings de-tune flavour-blind relations set by gauge couplings. Finally, issues relating to the discovery or exclusion of Susy at colliders are discussed. Bounds are derived for the masses of new particles from LHC searches for excesses of jets and missing energy without leptons, and compared to constraints arising from Higgs boson searches, for models of GMSB and the Constrained Minimal Supersymmetric Standard Model. I present a novel search strategy for new physics signatures with two neutral, stable particles, when such particles are produced by boosted decays. (Susy motivations include models with light gravitinos, pseudo-goldstinos, singlinos or new photinos.) The method is shown to produce sharp mass peaks that enhance the visibility of the signal, with mass reconstruction to 5% from O(100) events.
[ { "created": "Thu, 13 Jun 2013 14:24:30 GMT", "version": "v1" } ]
2013-06-14
[ [ "Wymant", "Chris", "" ] ]
This doctoral thesis addresses aspects of Supersymmetry (Susy) phenomenology. In addition to previously published work, it contains introductions to the following topics: from classical mechanics to quantum field theory for the more casual reader, electroweak naturalness, the Higgs as a pseudo-Nambu-Goldstone boson, the MSSM and NMSSM, simple and less simple models of gauge-mediated Susy breaking (GMSB), collider searches for Susy and other new theories, transverse mass observables with missing energy, and Brazil-band plots. The previously published work is as follows. The optimally natural Higgs-stop sector in the MSSM in light of the 2012 discovery of a Higgs boson is derived, namely that of almost maximal mixing, with the scalar top partners almost as light as can be. The discovery is also interpreted numerically in the NMSSM, with greater emphasis placed on the visibility of the Higgs boson at the observed mass, i.e. on signal strengths. I investigate the role played by the mediation scale of GMSB: this is found to be as a control of the extent to which Yukawa couplings de-tune flavour-blind relations set by gauge couplings. Finally, issues relating to the discovery or exclusion of Susy at colliders are discussed. Bounds are derived for the masses of new particles from LHC searches for excesses of jets and missing energy without leptons, and compared to constraints arising from Higgs boson searches, for models of GMSB and the Constrained Minimal Supersymmetric Standard Model. I present a novel search strategy for new physics signatures with two neutral, stable particles, when such particles are produced by boosted decays. (Susy motivations include models with light gravitinos, pseudo-goldstinos, singlinos or new photinos.) The method is shown to produce sharp mass peaks that enhance the visibility of the signal, with mass reconstruction to 5% from O(100) events.
hep-ph/0001206
Hani Kaldass
Arno R. Bohm, N. L. Harshman
On the Mass and Width of the Z-boson and Other Relativistic Quasistable Particles
23 pages
Nucl.Phys.B581:91-115,2000
10.1016/S0550-3213(00)00249-2
null
hep-ph quant-ph
null
The ambiguity in the definition for the mass and width of relativistic resonances is discussed, in particular for the case of the Z-boson. This ambiguity can be removed by requiring that a resonance's width $\Gamma$ (defined by a Breit-Wigner lineshape) and lifetime $\tau$ (defined by the exponential law) always and exactly fulfill the relation $\Gamma = \hbar/\tau$. To justify this one needs relativistic Gamow vectors which in turn define the resonance's mass M_R as the real part of the square root $\rm{Re}\sqrt{s_R}$ of the S-matrix pole position s_R. For the Z-boson this means that $M_R \approx M_Z - 26{MeV}$ and $\Gamma_R \approx \Gamma_Z-1.2{MeV}$ where M_Z and $\Gamma_Z$ are the values reported in the particle data tables.
[ { "created": "Wed, 19 Jan 2000 23:56:17 GMT", "version": "v1" } ]
2008-11-26
[ [ "Bohm", "Arno R.", "" ], [ "Harshman", "N. L.", "" ] ]
The ambiguity in the definition for the mass and width of relativistic resonances is discussed, in particular for the case of the Z-boson. This ambiguity can be removed by requiring that a resonance's width $\Gamma$ (defined by a Breit-Wigner lineshape) and lifetime $\tau$ (defined by the exponential law) always and exactly fulfill the relation $\Gamma = \hbar/\tau$. To justify this one needs relativistic Gamow vectors which in turn define the resonance's mass M_R as the real part of the square root $\rm{Re}\sqrt{s_R}$ of the S-matrix pole position s_R. For the Z-boson this means that $M_R \approx M_Z - 26{MeV}$ and $\Gamma_R \approx \Gamma_Z-1.2{MeV}$ where M_Z and $\Gamma_Z$ are the values reported in the particle data tables.
hep-ph/9809469
Ian Lawrie
Ian D Lawrie
Nonequilibrium quantum dynamics of phase transitions in an expanding universe
7pages, using RevTeX, no figures. Contribution to 5th International Workshop on Thermal Field Theories (Regensburg, August 1998). A few explanatory remarks added
null
null
null
hep-ph
null
I summarize the derivation of a set of Feynman rules appropriate for the perturbative description of the nonequilibrium dynamics of the symmetry-breaking phase transition in $\lambda\phi^4$ theory in a Robertson-Walker universe. The approximation scheme I develop provides for a treatment of dissipative effects which are essential to an adequate description of the nonequilibrium state. It also provides for the emergence from an initially symmetric state of a final state exhibiting the properties of spontaneous symmetry breaking without the introduction by hand of any explicit symmetry breaking.
[ { "created": "Mon, 21 Sep 1998 18:37:30 GMT", "version": "v1" }, { "created": "Thu, 15 Oct 1998 16:38:35 GMT", "version": "v2" } ]
2007-05-23
[ [ "Lawrie", "Ian D", "" ] ]
I summarize the derivation of a set of Feynman rules appropriate for the perturbative description of the nonequilibrium dynamics of the symmetry-breaking phase transition in $\lambda\phi^4$ theory in a Robertson-Walker universe. The approximation scheme I develop provides for a treatment of dissipative effects which are essential to an adequate description of the nonequilibrium state. It also provides for the emergence from an initially symmetric state of a final state exhibiting the properties of spontaneous symmetry breaking without the introduction by hand of any explicit symmetry breaking.
2109.10938
Motoo Suzuki
Seung J. Lee, Yuichiro Nakai, Motoo Suzuki
Multiple Hierarchies from a Warped Extra Dimension
41 pages, 7 figures; the radion kinetic term corrected but conclusion unchanged
null
10.1007/JHEP02(2022)050
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Theories beyond the Standard Model often contain mass scales hierarchically different from the electroweak scale and the Planck scale. It has been shown that such hierarchical mass scales can be realized as typical energy scales of multiple 3-branes in a 5D warped spacetime. We present a mechanism for stabilizing the intervals between the multiple 3-branes in the warped extra dimension, by introducing a single 5D scalar field with brane-localized potentials. We discuss the radion stabilization by solving the Einstein equation and the scalar field equation of motion so that a backreaction effect on the geometry due to the presence of the scalar field is taken into account. Perturbations from the background configuration are then considered with proper identification of multiple radion degrees of freedom. By solving their equations of motion, we compute the mass spectrum of the radion-scalar field system and the radion couplings to brane-localized matter fields, which are found to be suppressed by typical energy scales and radion profiles at the branes. We also compute the mass spectrum of Kaluza-Klein gravitons and their profiles in the extra dimension. Some applications of the setup are briefly described. Our analysis provides a solid ground to build 5D warped extra dimension models with multiple 3-branes.
[ { "created": "Wed, 22 Sep 2021 18:03:42 GMT", "version": "v1" }, { "created": "Thu, 13 Jan 2022 07:04:54 GMT", "version": "v2" } ]
2022-02-23
[ [ "Lee", "Seung J.", "" ], [ "Nakai", "Yuichiro", "" ], [ "Suzuki", "Motoo", "" ] ]
Theories beyond the Standard Model often contain mass scales hierarchically different from the electroweak scale and the Planck scale. It has been shown that such hierarchical mass scales can be realized as typical energy scales of multiple 3-branes in a 5D warped spacetime. We present a mechanism for stabilizing the intervals between the multiple 3-branes in the warped extra dimension, by introducing a single 5D scalar field with brane-localized potentials. We discuss the radion stabilization by solving the Einstein equation and the scalar field equation of motion so that a backreaction effect on the geometry due to the presence of the scalar field is taken into account. Perturbations from the background configuration are then considered with proper identification of multiple radion degrees of freedom. By solving their equations of motion, we compute the mass spectrum of the radion-scalar field system and the radion couplings to brane-localized matter fields, which are found to be suppressed by typical energy scales and radion profiles at the branes. We also compute the mass spectrum of Kaluza-Klein gravitons and their profiles in the extra dimension. Some applications of the setup are briefly described. Our analysis provides a solid ground to build 5D warped extra dimension models with multiple 3-branes.
hep-ph/9605260
null
Benjamin Grinstein and I.Z. Rothstein
Errors in Lattice Extractions of alpha_s Due to Use of Unphysical Pion Masses
Version to appear in PLB, with extended discussion and numbers for intermediate values of the pion mass
Phys.Lett. B385 (1996) 265-272
10.1016/0370-2693(96)00832-5
UCSD-TH-96-09
hep-ph hep-lat
null
We investigate the errors due to the use of unphysical values of light quark masses in lattice extractions of $\alpha_s$. A functional form for the pion mass dependence of the quarkonium mass splittings ($\Delta m$) is given as an expansion in $m_\pi/(4\pi f_\pi)$ and $m_\pi r_B$, where $r_B$ is the quarkonium Bohr radius. We find that, to lowest order,$\Delta m\simeq A+B m_\pi^2$, where the scale of $B$ is given by $f_\pi^2 r_B^3$. To order $m_\pi^4$ there are four unknown coefficients, however, utilizing multipole and operator product expansions, symmetry arguments eliminate one of the four unknowns. Using the central values for the lattice spacings which were extracted using two different, unphysical values for the pion mass, we find that the errors introduced by extrapolating to the physical regime are comparable to the errors quoted due to other sources. Extrapolation to physical values of the pion mass {\it increases} the value of $\alpha_s(M_Z)$, bringing its value closer to the high energy extractions.
[ { "created": "Thu, 9 May 1996 02:31:03 GMT", "version": "v1" }, { "created": "Thu, 25 Jul 1996 00:22:27 GMT", "version": "v2" } ]
2009-10-28
[ [ "Grinstein", "Benjamin", "" ], [ "Rothstein", "I. Z.", "" ] ]
We investigate the errors due to the use of unphysical values of light quark masses in lattice extractions of $\alpha_s$. A functional form for the pion mass dependence of the quarkonium mass splittings ($\Delta m$) is given as an expansion in $m_\pi/(4\pi f_\pi)$ and $m_\pi r_B$, where $r_B$ is the quarkonium Bohr radius. We find that, to lowest order,$\Delta m\simeq A+B m_\pi^2$, where the scale of $B$ is given by $f_\pi^2 r_B^3$. To order $m_\pi^4$ there are four unknown coefficients, however, utilizing multipole and operator product expansions, symmetry arguments eliminate one of the four unknowns. Using the central values for the lattice spacings which were extracted using two different, unphysical values for the pion mass, we find that the errors introduced by extrapolating to the physical regime are comparable to the errors quoted due to other sources. Extrapolation to physical values of the pion mass {\it increases} the value of $\alpha_s(M_Z)$, bringing its value closer to the high energy extractions.
1505.07750
Valery Kiselev
J. V. Balitsky, V. V. Kiselev, A. K. Likhoded, and V. D. Samoylenko
Mixing of $\eta - \eta'$ in charge-exchange reactions and decays of mesons with heavy quarks
13 pages, 12 figures, revtex4 style; clarifications, argumentations, comments and references added
Int.J.Mod.Phys. A31 (2016) no.18, 1650106
10.1142/S0217751X16501062
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Involving of elastic rescattering and annihilation of quark-antiquark pairs in a final state allows us to explain a dependence of ratio for cross sections of $\eta'$ and $\eta$ mesons versus transfer momentum in charge exchange reactions. We estimate the mixing angle of mesons with isoscalar states of $\bar u u+\bar d d$ and $\bar s s$ of hidden strangeness. The evaluation includes the consistent description of yield ratio for $\eta'$ and $\eta$ mesons in decays of $B^0$, $B^0_s$ and $J/\psi$ mesons.
[ { "created": "Wed, 27 May 2015 14:32:51 GMT", "version": "v1" }, { "created": "Mon, 1 Jun 2015 07:50:22 GMT", "version": "v2" }, { "created": "Fri, 12 Jun 2015 06:08:18 GMT", "version": "v3" }, { "created": "Mon, 9 Nov 2015 11:49:50 GMT", "version": "v4" } ]
2019-11-28
[ [ "Balitsky", "J. V.", "" ], [ "Kiselev", "V. V.", "" ], [ "Likhoded", "A. K.", "" ], [ "Samoylenko", "V. D.", "" ] ]
Involving of elastic rescattering and annihilation of quark-antiquark pairs in a final state allows us to explain a dependence of ratio for cross sections of $\eta'$ and $\eta$ mesons versus transfer momentum in charge exchange reactions. We estimate the mixing angle of mesons with isoscalar states of $\bar u u+\bar d d$ and $\bar s s$ of hidden strangeness. The evaluation includes the consistent description of yield ratio for $\eta'$ and $\eta$ mesons in decays of $B^0$, $B^0_s$ and $J/\psi$ mesons.
1807.03762
Junjie Cao
Junjie Cao, Jie Li, Yusi Pan, Liangliang Shang, Yuanfang Yue, Di Zhang
A Bayesian analysis of sneutrino DM in the NMSSM with Type-I seesaw mechanism
accepted version by PRD
Phys. Rev. D 99, 115033 (2019)
10.1103/PhysRevD.99.115033
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In the Next-to-Minimal Supersymmetric Standard Model (NMSSM) with extra heavy neutrino superfields, neutrino may acquire its mass via a seesaw mechanism and sneutrino may act as a viable dark matter (DM) candidate. Given the strong tension between the naturalness for $Z$ boson mass and the DM direct detection experiments for customary neutralino DM candidate, we augment the NMSSM with Type-I seesaw mechanism, which is the simplest extension of the theory to predict neutrino mass, and study the scenarios of sneutrino DM. We construct likelihood function with LHC Higgs data, B-physics measurements, DM relic density and its direct and indirect search limits, and perform a comprehensive scan over the parameter space of the theory by Nested Sampling method. We adopt both Bayesian and frequentist statistical quantities to illustrate the favored parameter space of the scenarios, the DM annihilation mechanism as well as the features of DM-nucleon scattering. We find that the scenarios are viable over broad parameter regions, especially the Higgsino mass $\mu$ can be below about $250 {\rm GeV}$ for a significant part of the region, which predicts $Z$ boson mass in a natural way. We also find that the DM usually co-annihilated with the Higgsinos to get the measured relic density, and consequently the DM-nucleon scattering rate is naturally suppressed to coincide with the recent XENON-1T results even for light Higgsinos. Other issues, such as the LHC search for the Higgsinos, are also addressed.
[ { "created": "Tue, 10 Jul 2018 17:10:46 GMT", "version": "v1" }, { "created": "Mon, 4 Mar 2019 03:52:49 GMT", "version": "v2" }, { "created": "Thu, 30 May 2019 09:26:44 GMT", "version": "v3" } ]
2019-07-03
[ [ "Cao", "Junjie", "" ], [ "Li", "Jie", "" ], [ "Pan", "Yusi", "" ], [ "Shang", "Liangliang", "" ], [ "Yue", "Yuanfang", "" ], [ "Zhang", "Di", "" ] ]
In the Next-to-Minimal Supersymmetric Standard Model (NMSSM) with extra heavy neutrino superfields, neutrino may acquire its mass via a seesaw mechanism and sneutrino may act as a viable dark matter (DM) candidate. Given the strong tension between the naturalness for $Z$ boson mass and the DM direct detection experiments for customary neutralino DM candidate, we augment the NMSSM with Type-I seesaw mechanism, which is the simplest extension of the theory to predict neutrino mass, and study the scenarios of sneutrino DM. We construct likelihood function with LHC Higgs data, B-physics measurements, DM relic density and its direct and indirect search limits, and perform a comprehensive scan over the parameter space of the theory by Nested Sampling method. We adopt both Bayesian and frequentist statistical quantities to illustrate the favored parameter space of the scenarios, the DM annihilation mechanism as well as the features of DM-nucleon scattering. We find that the scenarios are viable over broad parameter regions, especially the Higgsino mass $\mu$ can be below about $250 {\rm GeV}$ for a significant part of the region, which predicts $Z$ boson mass in a natural way. We also find that the DM usually co-annihilated with the Higgsinos to get the measured relic density, and consequently the DM-nucleon scattering rate is naturally suppressed to coincide with the recent XENON-1T results even for light Higgsinos. Other issues, such as the LHC search for the Higgsinos, are also addressed.
0711.1582
Michael Ratz
Michael Ratz
Notes on Local Grand Unification
Based on lectures given at the Summer Institute 2007, Fuji-Yoshida, Japan. The slides can be found at http://wwwhep.s.kanazawa-u.ac.jp/SI2007/slides/ratz.pdf
null
null
TUM-HEP 07/678
hep-ph hep-th
null
Grand unified models in four dimensions typically suffer from the doublet-triplet splitting problem. This obstacle can be overcome in higher-dimensional settings, where a non-trivial gauge group topography can explain the simultaneous appearance of complete standard model generations in the form of 16-plets of SO(10) and the Higgs fields as split multiplets. In these notes, the emerging scheme of `local grand unification' and its realization in the context of orbifold compactifications of the heterotic string are reviewed.
[ { "created": "Sat, 10 Nov 2007 10:31:29 GMT", "version": "v1" } ]
2011-11-10
[ [ "Ratz", "Michael", "" ] ]
Grand unified models in four dimensions typically suffer from the doublet-triplet splitting problem. This obstacle can be overcome in higher-dimensional settings, where a non-trivial gauge group topography can explain the simultaneous appearance of complete standard model generations in the form of 16-plets of SO(10) and the Higgs fields as split multiplets. In these notes, the emerging scheme of `local grand unification' and its realization in the context of orbifold compactifications of the heterotic string are reviewed.
2207.05828
Mustafa Ashry
M. Ashry, K. Ezzat and S. Khalil
Muon $g-2$ anomaly in a left-right model with an inverse seesaw mechanism
12 pages, 3 figures, 3 tables
Phys. Rev. D 107, 055044 (2023)
10.1103/PhysRevD.107.055044
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate the possibility of explanation for the muon anomalous magnetic moment $g_\mu-2$ in a left-right model with an inverse seesaw mechanism. We emphasize that the observed deviation from the Standard Model predictions can be accommodated in a large part of the parameter space of this class of models, where loops with massive neutrinos and charged Higgs boson as well as the weak $W$ boson contribute significantly to $g_\mu-2$. Stringent constraints due to lepton flavor violation $\mu\to{e}\gamma$, $\mu$-${e}$~conversion and the electron anomalous magnetic moment $g_e-2$ are considered, and the results are compatible.
[ { "created": "Tue, 12 Jul 2022 20:41:24 GMT", "version": "v1" }, { "created": "Thu, 30 Mar 2023 15:24:56 GMT", "version": "v2" } ]
2023-03-31
[ [ "Ashry", "M.", "" ], [ "Ezzat", "K.", "" ], [ "Khalil", "S.", "" ] ]
We investigate the possibility of explanation for the muon anomalous magnetic moment $g_\mu-2$ in a left-right model with an inverse seesaw mechanism. We emphasize that the observed deviation from the Standard Model predictions can be accommodated in a large part of the parameter space of this class of models, where loops with massive neutrinos and charged Higgs boson as well as the weak $W$ boson contribute significantly to $g_\mu-2$. Stringent constraints due to lepton flavor violation $\mu\to{e}\gamma$, $\mu$-${e}$~conversion and the electron anomalous magnetic moment $g_e-2$ are considered, and the results are compatible.
1612.07509
Henryk Czyz
Henryk Czy\.z and Patrycja Kisza
Testing $\chi_c$ properties at BELLE II
null
null
10.1016/j.physletb.2017.05.091
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The model of the $\chi_{c_i}-\gamma^*-\gamma^*$ and $\chi_{c_i}-J/\psi^*-\gamma^*$ form factors developed in [1] for $\chi_{c_1}$ and $\chi_{c_2}$ is extended to $\chi_{c_0}$ case. The studies performed within this model have shown that at BELLE II it will be possible to study in detail $\chi_{c_i}-\gamma^*-\gamma$ form factors through measurements of the reaction $e^+e^-\to e^+e^- \chi_{c_i} (\to J/\psi (\to \mu^+\mu^-)\gamma)$.The results were obtained using the newly updated Monte Carlo generator EKHARA.
[ { "created": "Thu, 22 Dec 2016 09:57:55 GMT", "version": "v1" }, { "created": "Thu, 18 May 2017 14:45:02 GMT", "version": "v2" } ]
2017-06-28
[ [ "Czyż", "Henryk", "" ], [ "Kisza", "Patrycja", "" ] ]
The model of the $\chi_{c_i}-\gamma^*-\gamma^*$ and $\chi_{c_i}-J/\psi^*-\gamma^*$ form factors developed in [1] for $\chi_{c_1}$ and $\chi_{c_2}$ is extended to $\chi_{c_0}$ case. The studies performed within this model have shown that at BELLE II it will be possible to study in detail $\chi_{c_i}-\gamma^*-\gamma$ form factors through measurements of the reaction $e^+e^-\to e^+e^- \chi_{c_i} (\to J/\psi (\to \mu^+\mu^-)\gamma)$.The results were obtained using the newly updated Monte Carlo generator EKHARA.
1411.2913
Antonio Enrique C\'arcamo Hern\'andez acarcamo
A. E. C\'arcamo Hern\'andez, Sergey Kovalenko, Iv\'an Schmidt
An SU(5) grand unified model with discrete flavour symmetries
14 pages. Title modified. arXiv admin note: text overlap with arXiv:1403.2525
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose a model based on the $SU(5)$ grand unification with an extra $Z_{2}\otimes Z_{2}^{\prime}\otimes Z_{2}^{\prime \prime}\otimes Z_{4}\otimes Z_{12}$ flavor symmetry, which successfully describes the observed SM fermion mass and mixing pattern. The observed quark mass and mixing pattern is caused by the $Z_{4}$ and $Z_{12}$ symmetries, which are broken at very high scale by the $SU(5)$ scalar singlets $\sigma $ and $\chi $, charged respectively under these symmetries and which acquire VEVs at the GUT scale. The light neutrino masses are generated via a type I seesaw mechanism with three heavy Majorana neutrinos. The model has in total 17 effective free parameters, from which 2 are fixed and 15 are fitted to reproduce the experimental values of the 18 physical parameters in the quark and lepton sectors. The model predictions for both quark and lepton sectors are in excellent agreement with the experimental data.
[ { "created": "Tue, 11 Nov 2014 18:37:07 GMT", "version": "v1" }, { "created": "Wed, 12 Nov 2014 18:35:45 GMT", "version": "v2" } ]
2014-11-13
[ [ "Hernández", "A. E. Cárcamo", "" ], [ "Kovalenko", "Sergey", "" ], [ "Schmidt", "Iván", "" ] ]
We propose a model based on the $SU(5)$ grand unification with an extra $Z_{2}\otimes Z_{2}^{\prime}\otimes Z_{2}^{\prime \prime}\otimes Z_{4}\otimes Z_{12}$ flavor symmetry, which successfully describes the observed SM fermion mass and mixing pattern. The observed quark mass and mixing pattern is caused by the $Z_{4}$ and $Z_{12}$ symmetries, which are broken at very high scale by the $SU(5)$ scalar singlets $\sigma $ and $\chi $, charged respectively under these symmetries and which acquire VEVs at the GUT scale. The light neutrino masses are generated via a type I seesaw mechanism with three heavy Majorana neutrinos. The model has in total 17 effective free parameters, from which 2 are fixed and 15 are fitted to reproduce the experimental values of the 18 physical parameters in the quark and lepton sectors. The model predictions for both quark and lepton sectors are in excellent agreement with the experimental data.
1604.07828
Seng Pei Liew
Koichi Hamaguchi, Seng Pei Liew
Models of 750 GeV quarkonium and the LHC excesses
22 pages, 7 figures
Phys. Rev. D 94, 035012 (2016)
10.1103/PhysRevD.94.035012
UT-16-17, IPMU-16-0060
hep-ph astro-ph.CO hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate models involving a vector-like quark X, which forms a 750 GeV bound state and reproduces the observed diphoton signals at the LHC, in connection with other excesses in the LHC data. An exotic hypercharge of -4/3 is required to fit the signal cross section, which indicates that there is additional particle(s) that mediates the decay of X in the full theory. We find that, introducing an SU(2) doublet vector-like quark of mass around 600 GeV in our UV-complete framework can accommodate not only the diphoton but also the on-Z excess (and potentially a slight excess in the monojet events). Our models also include a dark matter candidate. The most useful way to probe the models at the LHC is via monojet searches. The relic dark matter density is largely determined by coannihilation effects, and indirect detection of dark matter annihilation signals is the alternative and complementary probe of our models.
[ { "created": "Tue, 26 Apr 2016 20:00:06 GMT", "version": "v1" } ]
2016-08-17
[ [ "Hamaguchi", "Koichi", "" ], [ "Liew", "Seng Pei", "" ] ]
We investigate models involving a vector-like quark X, which forms a 750 GeV bound state and reproduces the observed diphoton signals at the LHC, in connection with other excesses in the LHC data. An exotic hypercharge of -4/3 is required to fit the signal cross section, which indicates that there is additional particle(s) that mediates the decay of X in the full theory. We find that, introducing an SU(2) doublet vector-like quark of mass around 600 GeV in our UV-complete framework can accommodate not only the diphoton but also the on-Z excess (and potentially a slight excess in the monojet events). Our models also include a dark matter candidate. The most useful way to probe the models at the LHC is via monojet searches. The relic dark matter density is largely determined by coannihilation effects, and indirect detection of dark matter annihilation signals is the alternative and complementary probe of our models.
hep-ph/0102139
Shuquan Nie
Shuquan Nie and Marc Sher (William and Mary)
Extra neutral gauge bosons and Higgs bosons in an E_6-based model
version to appear in Phys. Review D
Phys.Rev. D64 (2001) 073015
10.1103/PhysRevD.64.073015
WM-01-115
hep-ph
null
Extra neutral gauge bosons and Higgs bosons in an effective low-energy $SU(2)_L \times SU(2)_I \times U(1)_Y \times U(1)_{Y^{\prime}}$ model, which is a subgroup of $E_6$, are studied. $SU(2)_I$ is a subgroup of $SU(3)_R$ and commutes with the electric charge operator, so the three corresponding gauge bosons are neutral. Electroweak precision experiments are used to put constraints on masses of the extra neutral gauge bosons and on the mixings between them and the ordinary Z boson, including constraints arising from a proposed measurment of the weak charge of the proton at Jefferson Lab. Bounds on and relationships of masses of Higgs bosons in the supersymmetric version of the model are also discussed.
[ { "created": "Mon, 12 Feb 2001 17:35:42 GMT", "version": "v1" }, { "created": "Fri, 22 Jun 2001 15:36:47 GMT", "version": "v2" } ]
2009-11-07
[ [ "Nie", "Shuquan", "", "William and Mary" ], [ "Sher", "Marc", "", "William and Mary" ] ]
Extra neutral gauge bosons and Higgs bosons in an effective low-energy $SU(2)_L \times SU(2)_I \times U(1)_Y \times U(1)_{Y^{\prime}}$ model, which is a subgroup of $E_6$, are studied. $SU(2)_I$ is a subgroup of $SU(3)_R$ and commutes with the electric charge operator, so the three corresponding gauge bosons are neutral. Electroweak precision experiments are used to put constraints on masses of the extra neutral gauge bosons and on the mixings between them and the ordinary Z boson, including constraints arising from a proposed measurment of the weak charge of the proton at Jefferson Lab. Bounds on and relationships of masses of Higgs bosons in the supersymmetric version of the model are also discussed.
0802.4290
John F. Gunion
Hsin-Chia Cheng (U.C. Davis), Dalit Engelhardt (Boston U.), John F. Gunion (U.C. Davis), Zhenyu Han (U.C. Davis) and Bob McElrath (CERN)
Accurate Mass Determinations in Decay Chains with Missing Energy
6 figures, 4 pages
Phys.Rev.Lett.100:252001,2008
10.1103/PhysRevLett.100.252001
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Many beyond the Standard Model theories include a stable dark matter candidate that yields missing / invisible energy in collider detectors. If observed at the Large Hadron Collider, we must determine if its mass and other properties (and those of its partners) predict the correct dark matter relic density. We give a new procedure for determining its mass with small error.
[ { "created": "Thu, 28 Feb 2008 21:04:26 GMT", "version": "v1" } ]
2008-11-26
[ [ "Cheng", "Hsin-Chia", "", "U.C. Davis" ], [ "Engelhardt", "Dalit", "", "Boston U." ], [ "Gunion", "John F.", "", "U.C. Davis" ], [ "Han", "Zhenyu", "", "U.C. Davis" ], [ "McElrath", "Bob", "", "CERN" ] ]
Many beyond the Standard Model theories include a stable dark matter candidate that yields missing / invisible energy in collider detectors. If observed at the Large Hadron Collider, we must determine if its mass and other properties (and those of its partners) predict the correct dark matter relic density. We give a new procedure for determining its mass with small error.
1008.4572
Ana Carolina Bruno Machado Miss
A. C. B. Machado and V. Pleitez
Schizophrenic active neutrinos and exotic sterile neutrinos
I, A. C. B. Machado, apologize for having submitted the wrong file before. This is in fact the version to be published in Physics Letters B 698 (2011) pp. 128-130
Phys.Lett.B698:128-130,2011
10.1016/j.physletb.2011.02.051
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We implement a schizophrenic scenario for the active neutrinos in a model in which there are also exotic right-handed neutrinos making a model with a local U(1)_(B-L) anomaly free. Two of right-handed neutrinos carry B-L=-4 while the third one carries B-L=5.
[ { "created": "Thu, 26 Aug 2010 19:34:35 GMT", "version": "v1" }, { "created": "Fri, 27 Aug 2010 19:38:44 GMT", "version": "v2" }, { "created": "Mon, 30 Aug 2010 01:39:16 GMT", "version": "v3" }, { "created": "Fri, 29 Oct 2010 04:49:54 GMT", "version": "v4" }, { "created": "Wed, 16 Mar 2011 17:57:27 GMT", "version": "v5" }, { "created": "Thu, 17 Mar 2011 03:24:59 GMT", "version": "v6" } ]
2011-03-28
[ [ "Machado", "A. C. B.", "" ], [ "Pleitez", "V.", "" ] ]
We implement a schizophrenic scenario for the active neutrinos in a model in which there are also exotic right-handed neutrinos making a model with a local U(1)_(B-L) anomaly free. Two of right-handed neutrinos carry B-L=-4 while the third one carries B-L=5.
0811.3943
Paul Frampton
Paul H. Frampton
Doubly-Charged Boson Production in $p \bar{p}$ Collisions at $\sqrt{s} = 1.96$ TeV
5 pages latex
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It is suggested that the observed excess of muons in studies of $p \bar{p}$ collisions at $\sqrt{s} = 1.96$ TeV arises from the decay of doubly-charged bosons. Such particles are predicted in the 3-3-1 model where the electroweak gauge group is extended to $SU(3) \times U(1)$.
[ { "created": "Mon, 24 Nov 2008 19:03:12 GMT", "version": "v1" } ]
2008-11-25
[ [ "Frampton", "Paul H.", "" ] ]
It is suggested that the observed excess of muons in studies of $p \bar{p}$ collisions at $\sqrt{s} = 1.96$ TeV arises from the decay of doubly-charged bosons. Such particles are predicted in the 3-3-1 model where the electroweak gauge group is extended to $SU(3) \times U(1)$.
hep-ph/0607301
Athanasios Lahanas
A. B. Lahanas
LSP as a Candidate for Dark Matter
34 pages, 9 figures, Lectures given at 3rd Aegean Summer School: The Invisible Universe: Dark Matter and Dark Energy, Karfas, Island of Chios, Greece, 26 Sep - 1 Oct 2005. Typos added, references and comments added
Lect.NotesPhys.720:35-68,2007
10.1007/978-3-540-71013-4_2
null
hep-ph
null
The most recent observations by the WMAP satellite provided us with data of unprecedented accuracy regarding the parameters describing the Standard Cosmological Model. The current matter-energy density of the Universe is close to its critical value of which 73% is attributed to Dark Energy, 23% to Cold Dark Matter and only 4% is ordinary matter of baryonic nature. The origins of the Dark Energy (DE) and Dark Matter (DM) constitute the biggest challenge of Modern Astroparticle Physics. Particle theories, which will be tested in the next round experiments in large accelerators, such as the LHC, provide candidates for DM while at the same time can be consistent with the DE component. We give a pedagogical account on the DM problem and the possibility that this has supersymmetric origin.
[ { "created": "Thu, 27 Jul 2006 09:54:24 GMT", "version": "v1" }, { "created": "Sun, 10 Sep 2006 11:23:16 GMT", "version": "v2" } ]
2008-11-26
[ [ "Lahanas", "A. B.", "" ] ]
The most recent observations by the WMAP satellite provided us with data of unprecedented accuracy regarding the parameters describing the Standard Cosmological Model. The current matter-energy density of the Universe is close to its critical value of which 73% is attributed to Dark Energy, 23% to Cold Dark Matter and only 4% is ordinary matter of baryonic nature. The origins of the Dark Energy (DE) and Dark Matter (DM) constitute the biggest challenge of Modern Astroparticle Physics. Particle theories, which will be tested in the next round experiments in large accelerators, such as the LHC, provide candidates for DM while at the same time can be consistent with the DE component. We give a pedagogical account on the DM problem and the possibility that this has supersymmetric origin.
hep-ph/0204234
Carl Shakin
L.S. Celenza, Hu Li, C.M. Shakin, and Qing Sun
Quark and Nucleon Self-Energy in Dense Matter
19 pages, 8 figures, 2 tables, revtex
Phys.Rev. D66 (2002) 054010
10.1103/PhysRevD.66.054010
null
hep-ph nucl-th
null
In a recent work we introduced a nonlocal version of the Nambu--Jona-Lasinio(NJL) model that was designed to generate a quark self-energy in Euclidean space that was similar to that obtained in lattice simulations of QCD. In the present work we carry out related calculations in Minkowski space, so that we can study the effects of the significant vector and axial-vector interactions that appear in extended NJL models and which play an important role in the study of the $\rho$, $\omega$ and $a_1$ mesons. We study the modification of the quark self-energy in the presence of matter and find that our model reproduces the behavior of the quark condensate predicted by the model-independent relation $<\bar qq>_{\rho} = <\bar qq>_0(1-\sigma_N\rho_N/f_{\pi}^2m_{\pi}^2 +...)$, where $\sigma_N$ is the pion-nucleon sigma term and $\rho_N$ is the density of nuclear matter. (Since we do not include a model of confinement, our study is restricted to the analysis of quark matter. We provide some discussion of the modification of the above formula for quark matter.) The inclusion of a quark current mass leads to a second-order phase transition for the restoration of chiral symmetry. That restoration is about 80% at twice nuclear matter density for the model considered in this work. We also find that the part of the quark self-energy that is explicitly dependent upon density has a strong negative Lorentz-scalar term and a strong positive Lorentz-vector term, which is analogous to the self-energy found for the nucleon in nuclear matter when one makes use of the Dirac equation for the nucleon. In this work we calculate the nucleon self -energy in nuclear matter using our model of the quark self-energy and obtain satisfactory results.
[ { "created": "Fri, 19 Apr 2002 15:29:09 GMT", "version": "v1" } ]
2009-11-07
[ [ "Celenza", "L. S.", "" ], [ "Li", "Hu", "" ], [ "Shakin", "C. M.", "" ], [ "Sun", "Qing", "" ] ]
In a recent work we introduced a nonlocal version of the Nambu--Jona-Lasinio(NJL) model that was designed to generate a quark self-energy in Euclidean space that was similar to that obtained in lattice simulations of QCD. In the present work we carry out related calculations in Minkowski space, so that we can study the effects of the significant vector and axial-vector interactions that appear in extended NJL models and which play an important role in the study of the $\rho$, $\omega$ and $a_1$ mesons. We study the modification of the quark self-energy in the presence of matter and find that our model reproduces the behavior of the quark condensate predicted by the model-independent relation $<\bar qq>_{\rho} = <\bar qq>_0(1-\sigma_N\rho_N/f_{\pi}^2m_{\pi}^2 +...)$, where $\sigma_N$ is the pion-nucleon sigma term and $\rho_N$ is the density of nuclear matter. (Since we do not include a model of confinement, our study is restricted to the analysis of quark matter. We provide some discussion of the modification of the above formula for quark matter.) The inclusion of a quark current mass leads to a second-order phase transition for the restoration of chiral symmetry. That restoration is about 80% at twice nuclear matter density for the model considered in this work. We also find that the part of the quark self-energy that is explicitly dependent upon density has a strong negative Lorentz-scalar term and a strong positive Lorentz-vector term, which is analogous to the self-energy found for the nucleon in nuclear matter when one makes use of the Dirac equation for the nucleon. In this work we calculate the nucleon self -energy in nuclear matter using our model of the quark self-energy and obtain satisfactory results.
0809.0842
Robert Fleischer
Sven Faller, Robert Fleischer, Martin Jung, Thomas Mannel
The Golden Modes B^0 -> J/psi K_{S,L} in the Era of Precision Flavour Physics
4+1 pages, 4 figures
Phys.Rev.D79:014030,2009
10.1103/PhysRevD.79.014030
CERN-PH-TH/2008-166, SI-HEP-2008-12
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The B^0 -> J/\psi K_{S,L} channels are outstanding probes of CP violation. We have a detailed look at the associated Standard-Model uncertainties, which are related to doubly Cabibbo-suppressed penguin contributions, and point out that these usually neglected effects can actually be taken into account unambiguously through the CP asymmetries and the branching ratio of the B^0 -> J/\psi pi^0 decay. Using the most recent B-factory measurements, we find a negative shift of the extracted value of beta, which softens the tension in the fits of the unitarity triangle. In addition, this strategy can be used to constrain a possible new-physics phase in B^0-\bar B^0 mixing. The proposed strategy is crucial to fully exploit the tremendous accuracies for the search for this kind of new physics that can be achieved at the LHC and future super-flavour factories.
[ { "created": "Thu, 4 Sep 2008 15:37:09 GMT", "version": "v1" } ]
2009-02-26
[ [ "Faller", "Sven", "" ], [ "Fleischer", "Robert", "" ], [ "Jung", "Martin", "" ], [ "Mannel", "Thomas", "" ] ]
The B^0 -> J/\psi K_{S,L} channels are outstanding probes of CP violation. We have a detailed look at the associated Standard-Model uncertainties, which are related to doubly Cabibbo-suppressed penguin contributions, and point out that these usually neglected effects can actually be taken into account unambiguously through the CP asymmetries and the branching ratio of the B^0 -> J/\psi pi^0 decay. Using the most recent B-factory measurements, we find a negative shift of the extracted value of beta, which softens the tension in the fits of the unitarity triangle. In addition, this strategy can be used to constrain a possible new-physics phase in B^0-\bar B^0 mixing. The proposed strategy is crucial to fully exploit the tremendous accuracies for the search for this kind of new physics that can be achieved at the LHC and future super-flavour factories.
0809.3452
Jonathan Heckman
Jonathan J. Heckman and Cumrun Vafa
From F-theory GUTs to the LHC
v2: 34 pages, 2 figures, typos corrected
null
null
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper provides an overview to three recent papers on the bottom up approach to GUTs in F-theory. We assume only a minimal familiarity with string theory and phenomenology. After explaining the potential for predictive string phenomenology within this framework, we introduce the ingredients of F-theory GUTs, and show how these models naturally address various puzzles in four-dimensional GUT models. We next describe how supersymmetry is broken, and show that in a broad class of models, solving the mu/B mu problem requires a specific scale of supersymmetry breaking consistent with a particular deformation of the gauge mediation scenario. This rigid structure enables us to reliably extract predictions for the sparticle spectrum of the MSSM. A brief sketch of expected LHC signals, as well as ways to falsify this class of models is also included.
[ { "created": "Mon, 22 Sep 2008 14:01:17 GMT", "version": "v1" }, { "created": "Wed, 14 Jul 2010 02:07:29 GMT", "version": "v2" } ]
2010-07-15
[ [ "Heckman", "Jonathan J.", "" ], [ "Vafa", "Cumrun", "" ] ]
This paper provides an overview to three recent papers on the bottom up approach to GUTs in F-theory. We assume only a minimal familiarity with string theory and phenomenology. After explaining the potential for predictive string phenomenology within this framework, we introduce the ingredients of F-theory GUTs, and show how these models naturally address various puzzles in four-dimensional GUT models. We next describe how supersymmetry is broken, and show that in a broad class of models, solving the mu/B mu problem requires a specific scale of supersymmetry breaking consistent with a particular deformation of the gauge mediation scenario. This rigid structure enables us to reliably extract predictions for the sparticle spectrum of the MSSM. A brief sketch of expected LHC signals, as well as ways to falsify this class of models is also included.
hep-ph/9612471
Dharam V. Ahluwalia
D. V. Ahluwalia (LANL)
Notes on the Kinematic Structure of the Three-Flavor Neutrino Oscillation Framework
27 pages with 2 Figures (uses elsart style files). Updated references
Int.J.Mod.Phys.A12:5081-5102,1997
10.1142/S0217751X97002711
LA-UR-96-4865
hep-ph gr-qc
null
These notes present a critique of the standard three-flavor neutrino oscillation framwork. The design proposal of the MINOS at Fermilab based on a two mass eigenstate framework may require serious reconsideration if there is strong mixing between all three flavors of neutrinos. For the LSND and KARMEN neutrino oscillation experiments, the amplitude of neutrino oscillation of the ``one mass scale dominance''framework vanishes for certain values of mixing angles as a result of opposite signs of two equal and opposite contributions. Recent astronomical observations leave open the possibility that one of the neutrino mass eigenstates may be non-relativistic in some instances. Neutrino oscillation phenomenology with a superposition of two relativistic, and one non-relativistic, mass eigenstates is constructed. It is concluded that if the transition from the non-relativistic to the relativistic regime happens for energies relevant to the Reactor and the LSND neutrino oscillation experiments then one must consider an ab intio analysis of the existing data.
[ { "created": "Thu, 26 Dec 1996 21:22:12 GMT", "version": "v1" }, { "created": "Fri, 27 Dec 1996 18:45:23 GMT", "version": "v2" } ]
2008-11-26
[ [ "Ahluwalia", "D. V.", "", "LANL" ] ]
These notes present a critique of the standard three-flavor neutrino oscillation framwork. The design proposal of the MINOS at Fermilab based on a two mass eigenstate framework may require serious reconsideration if there is strong mixing between all three flavors of neutrinos. For the LSND and KARMEN neutrino oscillation experiments, the amplitude of neutrino oscillation of the ``one mass scale dominance''framework vanishes for certain values of mixing angles as a result of opposite signs of two equal and opposite contributions. Recent astronomical observations leave open the possibility that one of the neutrino mass eigenstates may be non-relativistic in some instances. Neutrino oscillation phenomenology with a superposition of two relativistic, and one non-relativistic, mass eigenstates is constructed. It is concluded that if the transition from the non-relativistic to the relativistic regime happens for energies relevant to the Reactor and the LSND neutrino oscillation experiments then one must consider an ab intio analysis of the existing data.
hep-ph/0003288
Elena Goubankova
E. Gubankova
Flow equations in the light-front QCD: mass gap and confinement
8 pages, uses sprocl.sty. To appear in the proceedings of the CSSM Workshop on Light-Cone QCD and Nonperturbative Hadron Physics, Adelaide, SA, Dec. 13--21,1999
null
null
null
hep-ph
null
The light-front QCD is studied using the method of flow equations. Solving the light-front gluon gap equation, the effective gluon mass is generated dynamically. The effective interaction between static quark and antiquark, generated through elimination of the quark-gluon minimal coupling by flow equations, has the Coulomb, $1/q^2$, and confining, $1/q^4$, singular behavior. Elimination of the quark-gluon coupling at small gluon momenta is governed by the cutoff dependent, dynamical gluon mass, which makes this elimination possible and provides such an enhancement at $q\sim 0$. The cutoff, which regulates small light-front $x$ divergences, sets up a scale for the dynamical gluon mass and the string tension in the $q\bar{q}$-potential. The mechanism of confimenemet in the light-front frame is suggested, based on the singular nature of the light-front gauge along the light-front $x$-axis.
[ { "created": "Thu, 30 Mar 2000 01:10:15 GMT", "version": "v1" } ]
2007-05-23
[ [ "Gubankova", "E.", "" ] ]
The light-front QCD is studied using the method of flow equations. Solving the light-front gluon gap equation, the effective gluon mass is generated dynamically. The effective interaction between static quark and antiquark, generated through elimination of the quark-gluon minimal coupling by flow equations, has the Coulomb, $1/q^2$, and confining, $1/q^4$, singular behavior. Elimination of the quark-gluon coupling at small gluon momenta is governed by the cutoff dependent, dynamical gluon mass, which makes this elimination possible and provides such an enhancement at $q\sim 0$. The cutoff, which regulates small light-front $x$ divergences, sets up a scale for the dynamical gluon mass and the string tension in the $q\bar{q}$-potential. The mechanism of confimenemet in the light-front frame is suggested, based on the singular nature of the light-front gauge along the light-front $x$-axis.
1208.0279
Ilan Fridman-Rojas
Ilan Fridman-Rojas and Peter Richardson
Next-to-Leading Order Simulation of Slepton Pair Production
12 pages, 3 figures
null
null
IPPP/12/55; DCPT/12/110; MCNET-12-11
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The next-to-leading order (NLO) corrections to Drell-Yan slepton pair production are merged with parton shower evolution via the POWHEG method in Herwig++. The NLO corrections at the level of event generation alter the shape of observables in a non-global way, thereby potentially affecting the fraction of signal events which pass crucial transverse momentum cuts on decay products and missing transverse momentum requirements on events. This effect is not captured by an overall rescaling of the cross section and can have repercussions on the reach of LHC searches.
[ { "created": "Wed, 1 Aug 2012 16:55:20 GMT", "version": "v1" } ]
2012-08-02
[ [ "Fridman-Rojas", "Ilan", "" ], [ "Richardson", "Peter", "" ] ]
The next-to-leading order (NLO) corrections to Drell-Yan slepton pair production are merged with parton shower evolution via the POWHEG method in Herwig++. The NLO corrections at the level of event generation alter the shape of observables in a non-global way, thereby potentially affecting the fraction of signal events which pass crucial transverse momentum cuts on decay products and missing transverse momentum requirements on events. This effect is not captured by an overall rescaling of the cross section and can have repercussions on the reach of LHC searches.
2208.02536
Alka Upadhyay
K. K. Vishwakarma, A. Upadhyay
Analysis of 2S singly heavy baryons in HQET
19 pages, 14 figures
null
null
null
hep-ph
http://creativecommons.org/licenses/by-sa/4.0/
We have employed HQET to determine the masses of radially excited ($n=2$) S-wave charm and bottom baryons. The HQET Lagrangian containing the non-perturbative parameters is shown with heavy baryon fields. The non-perturbative parameters, couplings, and decay widths are also studied for the S-wave singly heavy baryons. The HQET parameters $\overline{\Lambda}$, $\lambda_1$ and $\lambda_2$ are calculated for the ground state ($n=1$) using the masses of S-wave baryons. The mass term ratios of $n=1$ and $n=2$ mesons and baryons containing parameters $\overline{\Lambda}$ and $\lambda_1$ are studied by varying the bottom quark mass. This analysis shows that heavy quark behaves the same inside mesons and baryons in both 1S and 2S states. The HQET symmetry of $\overline{\Lambda}$ is used to find the parameters and masses for $n=2$ S-wave baryons. The variation of mass of 2S baryons with the non-perturbative parameters $\lambda_1$ and $\lambda_2$ is discussed. The Regge trajectories are also plotted in the $(n,M^2)$ plane using masses of $n=1$ and 2 charm and bottom baryons. The Regge trajectories are parallel and equidistant lines in the $(n,M^2)$ plane. We have also studied the strong decays of charm and bottom baryons for both $n=1$ and $n=2$ states. We have estimated the coupling constants $g_1=0.913^{+0.010}_{-0.017}$ and $g_2=0.559^{+0.006}_{-0.010}$ for $n=1$, and $\frac{\widetilde{g}_1}{\widetilde{g}_2}=1.52$ for $n=2$. We have also shown the semi-electronic decays rates of charm baryons in the spectator heavy quark approximation for $1S\rightarrow 1S$, $2S\rightarrow 1S$ and $2S\rightarrow 2S$ transitions. The decay rates for $1S\rightarrow 1S$ transitions are of same order as $2S\rightarrow 1S$ transitions. This analysis gives a good agreement with available theoretical and experimental data.
[ { "created": "Thu, 4 Aug 2022 09:09:58 GMT", "version": "v1" }, { "created": "Thu, 6 Oct 2022 09:26:05 GMT", "version": "v2" }, { "created": "Wed, 31 May 2023 08:24:59 GMT", "version": "v3" }, { "created": "Thu, 3 Aug 2023 11:19:47 GMT", "version": "v4" } ]
2023-08-04
[ [ "Vishwakarma", "K. K.", "" ], [ "Upadhyay", "A.", "" ] ]
We have employed HQET to determine the masses of radially excited ($n=2$) S-wave charm and bottom baryons. The HQET Lagrangian containing the non-perturbative parameters is shown with heavy baryon fields. The non-perturbative parameters, couplings, and decay widths are also studied for the S-wave singly heavy baryons. The HQET parameters $\overline{\Lambda}$, $\lambda_1$ and $\lambda_2$ are calculated for the ground state ($n=1$) using the masses of S-wave baryons. The mass term ratios of $n=1$ and $n=2$ mesons and baryons containing parameters $\overline{\Lambda}$ and $\lambda_1$ are studied by varying the bottom quark mass. This analysis shows that heavy quark behaves the same inside mesons and baryons in both 1S and 2S states. The HQET symmetry of $\overline{\Lambda}$ is used to find the parameters and masses for $n=2$ S-wave baryons. The variation of mass of 2S baryons with the non-perturbative parameters $\lambda_1$ and $\lambda_2$ is discussed. The Regge trajectories are also plotted in the $(n,M^2)$ plane using masses of $n=1$ and 2 charm and bottom baryons. The Regge trajectories are parallel and equidistant lines in the $(n,M^2)$ plane. We have also studied the strong decays of charm and bottom baryons for both $n=1$ and $n=2$ states. We have estimated the coupling constants $g_1=0.913^{+0.010}_{-0.017}$ and $g_2=0.559^{+0.006}_{-0.010}$ for $n=1$, and $\frac{\widetilde{g}_1}{\widetilde{g}_2}=1.52$ for $n=2$. We have also shown the semi-electronic decays rates of charm baryons in the spectator heavy quark approximation for $1S\rightarrow 1S$, $2S\rightarrow 1S$ and $2S\rightarrow 2S$ transitions. The decay rates for $1S\rightarrow 1S$ transitions are of same order as $2S\rightarrow 1S$ transitions. This analysis gives a good agreement with available theoretical and experimental data.