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1705.00913
Beatrix Hiesmayr C.
K. Simonov and B.C. Hiesmayr
Can a spontaneous collapse in flavour oscillations be tested at KLOE?
To appear in the proceedings of the KLOE-2 Workshop on e+e- collision physics at 1 GeV, 26-28 October 2016, INFN - Laboratori Nazionali di Frascati, Italy
EPJ Web of Conferences 166, 00006 (2018)
10.1051/epjconf/201816600006
null
hep-ph quant-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Why do we never see a table in a superposition of here and there? This problem gets a solution by so called collapse models assuming the collapse as a genuinely physical process. Here we consider two specific collapse models and apply them to systems at high energies, i.e. flavour oscillating neutral meson systems. We find on one hand a potentially new interpretation of the decay rates introduced by hand in the standard formalism and on the other hand that these systems at high energies constrain by experimental data the possible collapse scenarios.
[ { "created": "Tue, 2 May 2017 11:17:18 GMT", "version": "v1" } ]
2018-10-01
[ [ "Simonov", "K.", "" ], [ "Hiesmayr", "B. C.", "" ] ]
Why do we never see a table in a superposition of here and there? This problem gets a solution by so called collapse models assuming the collapse as a genuinely physical process. Here we consider two specific collapse models and apply them to systems at high energies, i.e. flavour oscillating neutral meson systems. We find on one hand a potentially new interpretation of the decay rates introduced by hand in the standard formalism and on the other hand that these systems at high energies constrain by experimental data the possible collapse scenarios.
0811.1670
Prakash Mathews
M. C. Kumar, Prakash Mathews, V. Ravindran, Anurag Tripathi
Diphoton signals in theories with large extra dimensions to NLO QCD at hadron colliders
13 pages, 5 figures. To appear in PLB
Phys.Lett.B672:45-50,2009
10.1016/j.physletb.2009.01.002
SINP/TNP/2008/20
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a full next-to-leading order (NLO) QCD corrections to diphoton production at the hadron colliders in both standard model and ADD model. The invariant mass and rapidity distributions of the diphotons are obtained using a semi-analytical two cut-off phase space slicing method which allows for a successful numerical implementation of various kinematical cuts used in the experiments. The fragmentation photons are systematically removed using smooth-cone-isolation cuts on the photons. The NLO QCD corrections not only stabilise the perturbative predictions but also enhance the production cross section significantly.
[ { "created": "Tue, 11 Nov 2008 10:40:03 GMT", "version": "v1" }, { "created": "Mon, 12 Jan 2009 06:03:21 GMT", "version": "v2" } ]
2009-02-02
[ [ "Kumar", "M. C.", "" ], [ "Mathews", "Prakash", "" ], [ "Ravindran", "V.", "" ], [ "Tripathi", "Anurag", "" ] ]
We present a full next-to-leading order (NLO) QCD corrections to diphoton production at the hadron colliders in both standard model and ADD model. The invariant mass and rapidity distributions of the diphotons are obtained using a semi-analytical two cut-off phase space slicing method which allows for a successful numerical implementation of various kinematical cuts used in the experiments. The fragmentation photons are systematically removed using smooth-cone-isolation cuts on the photons. The NLO QCD corrections not only stabilise the perturbative predictions but also enhance the production cross section significantly.
1211.4716
Wolfgang Lucha
Wolfgang Lucha and Franz F. Schoberl
Exact Solutions of Bethe-Salpeter Equations with Instantaneous Interactions
16 pages, 3 figures; v2: slightly augmented summary, matches version in PRD
Phys. Rev. D 87, 016009 (2013)
10.1103/PhysRevD.87.016009
HEPHY-PUB 921/12
hep-ph hep-th nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Bethe-Salpeter approach allows for quantum-field-theoretic descriptions of relativistic bound states; its inherent complexity, however, usually prevents to find its exact solutions. Under suitable simplifying assumptions about the systems discussed, we derive analytically some examples of rigorous solutions to the instantaneous homogeneous Bethe-Salpeter equation by relating tentative solutions to the interactions responsible for the formation of bound states.
[ { "created": "Tue, 20 Nov 2012 11:28:05 GMT", "version": "v1" }, { "created": "Mon, 7 Jan 2013 12:14:27 GMT", "version": "v2" } ]
2013-05-30
[ [ "Lucha", "Wolfgang", "" ], [ "Schoberl", "Franz F.", "" ] ]
The Bethe-Salpeter approach allows for quantum-field-theoretic descriptions of relativistic bound states; its inherent complexity, however, usually prevents to find its exact solutions. Under suitable simplifying assumptions about the systems discussed, we derive analytically some examples of rigorous solutions to the instantaneous homogeneous Bethe-Salpeter equation by relating tentative solutions to the interactions responsible for the formation of bound states.
2107.14511
Anh Dung Le
Anh Dung Le
Diffractive dissociation in future electron-ion colliders
7 pages, 2 figures; Submission to SciPost, Contribution to the XXVIII International Workshop on Deep-Inelastic Scattering and Related Subjects (DIS2021)
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study diffractive scattering cross sections, focusing on the rapidity gap distribution in realistic kinematics at future electron-ion colliders. Our study consists in numerical solutions of the QCD evolution equations in both fixed and running coupling frameworks. The fixed and the running coupling equations are shown to lead to different shapes for the rapidity gap distribution. The obtained distribution when the coupling is fixed exhibits a shape characteristic of a recently developed model for diffractive dissociation, which indicates the relevance of the study of that diffractive observable for the partonic-level understanding of diffraction.
[ { "created": "Fri, 30 Jul 2021 09:40:19 GMT", "version": "v1" } ]
2021-08-02
[ [ "Le", "Anh Dung", "" ] ]
We study diffractive scattering cross sections, focusing on the rapidity gap distribution in realistic kinematics at future electron-ion colliders. Our study consists in numerical solutions of the QCD evolution equations in both fixed and running coupling frameworks. The fixed and the running coupling equations are shown to lead to different shapes for the rapidity gap distribution. The obtained distribution when the coupling is fixed exhibits a shape characteristic of a recently developed model for diffractive dissociation, which indicates the relevance of the study of that diffractive observable for the partonic-level understanding of diffraction.
1302.4892
Andrzej Siodmok
Stefan Gieseke, Christian Rohr (Karlsruhe U., ITP) and Andrzej Siodmok (University of Manchester)
Multiple Partonic Interactions in Herwig++
6 pages, 4 figures; Talk presented at the 42. International Symposium on Multiparticle Dynamics, 16-21 September 2012, Kielce, Poland
null
null
KA-TP-05-2013, MAN/HEP/2013/03, MCnet-13-02
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We review the implementation of a model for multiple partonic interactions in Herwig++. Moreover, we show how recent studies on the colour structure of events in Herwig++ led to a significant improvement in the description of soft inclusive observables in pp interactions at the LHC.
[ { "created": "Wed, 20 Feb 2013 12:57:49 GMT", "version": "v1" } ]
2013-02-21
[ [ "Gieseke", "Stefan", "", "Karlsruhe U., ITP" ], [ "Rohr", "Christian", "", "Karlsruhe U., ITP" ], [ "Siodmok", "Andrzej", "", "University of Manchester" ] ]
We review the implementation of a model for multiple partonic interactions in Herwig++. Moreover, we show how recent studies on the colour structure of events in Herwig++ led to a significant improvement in the description of soft inclusive observables in pp interactions at the LHC.
1410.7142
Priyanka Fakay
Priyanka Fakay
Revisiting texture 5 zero quark mass matrices
4 pages, 2 figures
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The question of viability of texture 5 zero Fritzsch-like quark mass matrices are examined in the context of the latest quark mixing data.
[ { "created": "Mon, 27 Oct 2014 07:36:21 GMT", "version": "v1" } ]
2014-10-28
[ [ "Fakay", "Priyanka", "" ] ]
The question of viability of texture 5 zero Fritzsch-like quark mass matrices are examined in the context of the latest quark mixing data.
hep-ph/0501062
Yuri Markov Adolfovich
Yu.A. Markov, M.A. Markova, A.N. Vall
Nonlinear dynamics of soft boson collective excitations in hot QCD plasma III: bremsstrahlung and energy losses
68 pages, 9 EPS figures; added new sections 8, 10 and references
Annals Phys. 320 (2005) 282-343
10.1016/j.aop.2005.06.005
ISDCT-05-1
hep-ph
null
Within of the framework of semiclassical approximation a general formalism for deriving an effective current generating bremsstrahlung of arbitrary number of soft gluons (longitudinal or transverse ones) in scattering of higher-energy parton off thermal parton in hot quark-gluon plasma with subsequent extension to two and more scatterers, is obtained. For the case of static color centers an expression for energy loss induced by usual bremsstrahlung of lowest-order with allowance for an effective temperature-induced gluon mass and finite mass of the projectile (heavy quark), is derived. The detailed analysis of contribution to radiation energy loss associated with existence of effective three-gluon vertex induced by hot QCD medium, is performed. It is shown that in general, the bremsstrahlung associated with this vertex have no sharp direction (as in the case of usual bremsstrahlung) and therefore here, we can expect an absence of suppression effect due to multiple scattering. For the case of two color static scattering centers it was shown that the problem of calculation of bremsstrahlung induced by four-gluon hard thermal loop (HTL) vertex correction can be reduced to the problem of the calculation of bremsstrahlung induced by three-gluon HTL correction. It was shown that for limiting value of soft gluon occupation number $N_{\bf k}\sim 1/\alpha_s$ all higher processes of bremsstrahlung of arbitrary number of soft gluons become of the same order in coupling, and the problem of resummation of all relevant contributions to radiation energy loss of fast parton, arises. An explicit expression for matrix element of two soft gluon bremsstrahlung in small angles approximation is obtained.
[ { "created": "Sun, 9 Jan 2005 13:21:41 GMT", "version": "v1" }, { "created": "Mon, 14 Mar 2005 06:17:27 GMT", "version": "v2" } ]
2007-05-23
[ [ "Markov", "Yu. A.", "" ], [ "Markova", "M. A.", "" ], [ "Vall", "A. N.", "" ] ]
Within of the framework of semiclassical approximation a general formalism for deriving an effective current generating bremsstrahlung of arbitrary number of soft gluons (longitudinal or transverse ones) in scattering of higher-energy parton off thermal parton in hot quark-gluon plasma with subsequent extension to two and more scatterers, is obtained. For the case of static color centers an expression for energy loss induced by usual bremsstrahlung of lowest-order with allowance for an effective temperature-induced gluon mass and finite mass of the projectile (heavy quark), is derived. The detailed analysis of contribution to radiation energy loss associated with existence of effective three-gluon vertex induced by hot QCD medium, is performed. It is shown that in general, the bremsstrahlung associated with this vertex have no sharp direction (as in the case of usual bremsstrahlung) and therefore here, we can expect an absence of suppression effect due to multiple scattering. For the case of two color static scattering centers it was shown that the problem of calculation of bremsstrahlung induced by four-gluon hard thermal loop (HTL) vertex correction can be reduced to the problem of the calculation of bremsstrahlung induced by three-gluon HTL correction. It was shown that for limiting value of soft gluon occupation number $N_{\bf k}\sim 1/\alpha_s$ all higher processes of bremsstrahlung of arbitrary number of soft gluons become of the same order in coupling, and the problem of resummation of all relevant contributions to radiation energy loss of fast parton, arises. An explicit expression for matrix element of two soft gluon bremsstrahlung in small angles approximation is obtained.
hep-ph/0209094
J. W. F. Valle
C. Burgess, N.S. Dzhalilov, M. Maltoni, T.I. Rashba, V.B. Semikoz, M.A. Tortola, J.W.F. Valle
Large mixing angle oscillations as a probe of the deep solar interior
13 pages, LaTeX file using AASLaTeX, 6 figures included. Improved version including the new KamLAND data. To appear in APJ letters
Astrophys.J.588:L65,2003
10.1086/375482
IFIC/02-37
hep-ph astro-ph
null
We re-examine the sensitivity of solar neutrino oscillations to noise in the solar interior using the best current estimates of neutrino properties. Our results show that the measurement of neutrino properties at KamLAND provides new information about fluctuations in the solar environment on scales to which standard helioseismic constraints are largely insensitive. We also show how the determination of neutrino oscillation parameters from a combined fit of KamLAND and solar data depends strongly on the magnitude of solar density fluctuations. We argue that a resonance between helioseismic and Alfven waves might provide a physical mechanism for generating these fluctuations and, if so, neutrino-oscillation measurements could be used to constrain the size of magnetic fields deep within the solar radiative zone.
[ { "created": "Mon, 9 Sep 2002 15:52:02 GMT", "version": "v1" }, { "created": "Thu, 20 Mar 2003 14:13:15 GMT", "version": "v2" } ]
2009-11-07
[ [ "Burgess", "C.", "" ], [ "Dzhalilov", "N. S.", "" ], [ "Maltoni", "M.", "" ], [ "Rashba", "T. I.", "" ], [ "Semikoz", "V. B.", "" ], [ "Tortola", "M. A.", "" ], [ "Valle", "J. W. F.", "" ] ]
We re-examine the sensitivity of solar neutrino oscillations to noise in the solar interior using the best current estimates of neutrino properties. Our results show that the measurement of neutrino properties at KamLAND provides new information about fluctuations in the solar environment on scales to which standard helioseismic constraints are largely insensitive. We also show how the determination of neutrino oscillation parameters from a combined fit of KamLAND and solar data depends strongly on the magnitude of solar density fluctuations. We argue that a resonance between helioseismic and Alfven waves might provide a physical mechanism for generating these fluctuations and, if so, neutrino-oscillation measurements could be used to constrain the size of magnetic fields deep within the solar radiative zone.
hep-ph/9501272
Gabor Cynolter
G.Cynolter, E.Lendvai and G. Pocsik
OBLIQUE RADIATIVE CORRECTIONS IN THE VECTOR CONDENSATE MODEL OF ELECTROWEAK INTERACTIONS
6 pages LATEX, 1 Latex figure included
Mod.Phys.Lett. A10 (1995) 2193
10.1142/S0217732395002350
ITP-Budapest Report No. 508
hep-ph
null
Oblique radiative corrections are calculated to the parameter $S$ in a version of the standard model where the Higgs doublet is replaced by a doublet of vector bosons and the gauge symmetry is broken dynamically. We show that to each momentum scale there exists a domain of the masses of charged and neutral vector bosons where $S$ is compatible with the experiments. At a scale of 1 TeV this requires vector boson masses of at least $m_0 \approx $ 400--550 GeV, $ m_+ \approx $ 200--350 GeV.
[ { "created": "Wed, 11 Jan 1995 14:48:31 GMT", "version": "v1" } ]
2015-06-25
[ [ "Cynolter", "G.", "" ], [ "Lendvai", "E.", "" ], [ "Pocsik", "G.", "" ] ]
Oblique radiative corrections are calculated to the parameter $S$ in a version of the standard model where the Higgs doublet is replaced by a doublet of vector bosons and the gauge symmetry is broken dynamically. We show that to each momentum scale there exists a domain of the masses of charged and neutral vector bosons where $S$ is compatible with the experiments. At a scale of 1 TeV this requires vector boson masses of at least $m_0 \approx $ 400--550 GeV, $ m_+ \approx $ 200--350 GeV.
1210.1436
Andreas von Manteuffel
Andreas von Manteuffel, Cedric Studerus
Top quark pairs at two loops and Reduze 2
7 pages, talk given at Loops and Legs 2012
null
null
null
hep-ph hep-th physics.comp-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We report on progress for the analytical calculation of the two-loop corrections to top quark pair production at hadron colliders. For the light fermionic corrections in the gluon channel, we discuss the analytical solution for the master integrals of a non-planar double box with a massive propagator. The result in terms of Goncharov's multiple polylogarithms is handled using systematic reductions based on the symbol map and the coproduct. We discuss new features of the computer program Reduze 2. It provides a fully distributed variant of Laporta's algorithm to reduce loop integrals. New graph matroid based algorithms allow to calculate shift relations between Feynman integrals in a fully automated way.
[ { "created": "Thu, 4 Oct 2012 13:40:05 GMT", "version": "v1" } ]
2012-10-05
[ [ "von Manteuffel", "Andreas", "" ], [ "Studerus", "Cedric", "" ] ]
We report on progress for the analytical calculation of the two-loop corrections to top quark pair production at hadron colliders. For the light fermionic corrections in the gluon channel, we discuss the analytical solution for the master integrals of a non-planar double box with a massive propagator. The result in terms of Goncharov's multiple polylogarithms is handled using systematic reductions based on the symbol map and the coproduct. We discuss new features of the computer program Reduze 2. It provides a fully distributed variant of Laporta's algorithm to reduce loop integrals. New graph matroid based algorithms allow to calculate shift relations between Feynman integrals in a fully automated way.
1308.2044
J. P. Ma
J.P. Ma and G.P. Zhang
QCD Corrections of All Structure Functions in Transverse Momentum Dependent Factorization for Drell-Yan Processes
published version in JHEP 1402 (2014) 100
null
10.1007/JHEP02(2014)100
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the one-loop correction in Transverse-Momentum-Dependent(TMD) factorization for Drell-Yan processes at small transverse momentum of the lepton pair. We adopt the so-called subtractive approach, in which one can systematically construct contributions for subtracting long-distance effects represented by diagrams. The perturbative parts are obtained after the subtraction. We find that the perturbative coefficients of all structure functions in TMD factorization at leading twist are the same. The perturbative parts can also be studied with scattering of partons instead of hadrons. In this way, the factorization of many structure functions can only be examined by studying the scattering of multi-parton states, where there are many diagrams. These diagrams have no similarities to those treated in the subtractive approach. As an example, we use existing results of one structure function responsible for Single-Spin-Asymmetry, to show that these diagrams in the scattering of multi-parton states are equivalent to those treated in the subtractive approach after using Ward identity.
[ { "created": "Fri, 9 Aug 2013 07:33:45 GMT", "version": "v1" }, { "created": "Tue, 10 Sep 2013 03:06:52 GMT", "version": "v2" }, { "created": "Tue, 8 Apr 2014 07:21:06 GMT", "version": "v3" } ]
2014-04-09
[ [ "Ma", "J. P.", "" ], [ "Zhang", "G. P.", "" ] ]
We study the one-loop correction in Transverse-Momentum-Dependent(TMD) factorization for Drell-Yan processes at small transverse momentum of the lepton pair. We adopt the so-called subtractive approach, in which one can systematically construct contributions for subtracting long-distance effects represented by diagrams. The perturbative parts are obtained after the subtraction. We find that the perturbative coefficients of all structure functions in TMD factorization at leading twist are the same. The perturbative parts can also be studied with scattering of partons instead of hadrons. In this way, the factorization of many structure functions can only be examined by studying the scattering of multi-parton states, where there are many diagrams. These diagrams have no similarities to those treated in the subtractive approach. As an example, we use existing results of one structure function responsible for Single-Spin-Asymmetry, to show that these diagrams in the scattering of multi-parton states are equivalent to those treated in the subtractive approach after using Ward identity.
hep-ph/9406394
Pankaj Jain
Pankaj Jain and John P. Ralston
Evidence for Gluon Energy Loss as the Mechanism for Heavy Quarkonium Suppression in $pA$ Collisions
26 pages, 15 figures (not included, hard copy available upon request), report # KANSAS 94-5-22
null
null
null
hep-ph nucl-th
null
We study the energy and nuclear A dependence of the hadronic production of heavy quarkonia. We review theoretical ideas which have been put forward, seeking a consistent global picture reconciling the large effects in quarkonia with the small nuclear effects observed in continuum Drell Yan production. The data indicates that shadowing or leading twist modifications of parton distributions can be ruled out as explanations, leaving higher twist energy loss. {}From general principles the maximum allowed energy loss of partons traversing the nuclear medium can be related to the parton transverse momenta. We then show that the experimental data on nuclear suppression of charm- and bottom- onium for large $x_F$ is consistent with this effect: using the observed transverse momenta to bound the $x_F$ dependence in an almost model independent manner generates a relation that practically reproduces the data. Several prediction are discussed; the dependence on $x_F$ as $x_F\to 1$, and large and small $k_T^2$ cuts, can be used to discriminate between quark and gluon induced effects.
[ { "created": "Sat, 25 Jun 1994 16:27:05 GMT", "version": "v1" } ]
2009-09-25
[ [ "Jain", "Pankaj", "" ], [ "Ralston", "John P.", "" ] ]
We study the energy and nuclear A dependence of the hadronic production of heavy quarkonia. We review theoretical ideas which have been put forward, seeking a consistent global picture reconciling the large effects in quarkonia with the small nuclear effects observed in continuum Drell Yan production. The data indicates that shadowing or leading twist modifications of parton distributions can be ruled out as explanations, leaving higher twist energy loss. {}From general principles the maximum allowed energy loss of partons traversing the nuclear medium can be related to the parton transverse momenta. We then show that the experimental data on nuclear suppression of charm- and bottom- onium for large $x_F$ is consistent with this effect: using the observed transverse momenta to bound the $x_F$ dependence in an almost model independent manner generates a relation that practically reproduces the data. Several prediction are discussed; the dependence on $x_F$ as $x_F\to 1$, and large and small $k_T^2$ cuts, can be used to discriminate between quark and gluon induced effects.
hep-ph/9905420
Gino Isidori
G. D'Ambrosio, G. Ecker, G. Isidori and H. Neufeld
eta -> pi^+ pi^- pi^0 gamma in Chiral Perturbation Theory
13 pages, 1 fig; minor modifications (results unchanged)
Phys.Lett. B466 (1999) 337-344
10.1016/S0370-2693(99)01144-2
LNF-99/009(P), INFNNA-IV-99/12, UWThPh-1999-19
hep-ph
null
We analyse the radiative decay $\eta \to \pi^+\pi^- \pi^0\gamma$ in the low--energy expansion of the Standard Model. We employ the notion of ``generalized bremsstrahlung'' to take full advantage of the theoretical and experimental information on the corresponding non-radiative $\eta \to 3 \pi$ decay. The direct emission amplitude of ${\cal O}(p^4)$ is due to one-loop diagrams with intermediate pions (isospin violating) and kaons (isospin conserving). The isospin conserving contributions to direct emission, including vector meson exchange appearing at ${\cal O}(p^6)$, are suppressed.
[ { "created": "Thu, 20 May 1999 14:49:51 GMT", "version": "v1" }, { "created": "Fri, 18 Jun 1999 08:31:19 GMT", "version": "v2" } ]
2009-10-31
[ [ "D'Ambrosio", "G.", "" ], [ "Ecker", "G.", "" ], [ "Isidori", "G.", "" ], [ "Neufeld", "H.", "" ] ]
We analyse the radiative decay $\eta \to \pi^+\pi^- \pi^0\gamma$ in the low--energy expansion of the Standard Model. We employ the notion of ``generalized bremsstrahlung'' to take full advantage of the theoretical and experimental information on the corresponding non-radiative $\eta \to 3 \pi$ decay. The direct emission amplitude of ${\cal O}(p^4)$ is due to one-loop diagrams with intermediate pions (isospin violating) and kaons (isospin conserving). The isospin conserving contributions to direct emission, including vector meson exchange appearing at ${\cal O}(p^6)$, are suppressed.
hep-ph/9706437
Dieter Zeppenfeld
Erwin Mirkes (U.Karlsruhe) and Dieter Zeppenfeld (UW-Madison)
Jet Production in DIS at NLO
6 pages, Latex, Talk given at 5th International Workshop on Deep Inelastic Scattering and QCD, Chicago, Illinois, USA, 14-18 April 1997
null
10.1063/1.53648
MADPH-97-1002
hep-ph
null
Dijet production in DIS is an important laboratory for testing our understanding of perturbative QCD. Flexible NLO Monte Carlo programs allow to investigate general jet definition schemes. For forward jet production at $p_{Tj} \approx Q$ and $x_{jet} >> x$ the NLO predictions fall well below HERA data, thus providing evidence for BFKL dynamics.
[ { "created": "Fri, 20 Jun 1997 14:54:11 GMT", "version": "v1" } ]
2009-10-30
[ [ "Mirkes", "Erwin", "", "U.Karlsruhe" ], [ "Zeppenfeld", "Dieter", "", "UW-Madison" ] ]
Dijet production in DIS is an important laboratory for testing our understanding of perturbative QCD. Flexible NLO Monte Carlo programs allow to investigate general jet definition schemes. For forward jet production at $p_{Tj} \approx Q$ and $x_{jet} >> x$ the NLO predictions fall well below HERA data, thus providing evidence for BFKL dynamics.
hep-ph/9510262
Rodolfo Sassot
D. de Florian, C.A. Garcia Canal, R. Sassot
Factorization in Semi-Inclusive Polarized Deep Inelastic Scattering
16 pages, figures included using FEYNMAN macro
Nucl.Phys. B470 (1996) 195-210
10.1016/0550-3213(96)00159-9
null
hep-ph
null
We calculate and analize the ${\cal{O}}(\alpha_s)$ one-particle inclusive cross section in polarized deep inelastic lepton-hadron scattering, using dimensional regularization and the HVBM prescription for $\gamma_5$. We discuss the factorization of all the collinear singularities related to the process, particularly those which are absorbed in the redefinition of the spin dependent analogue of the recently introduced fracture functions. This is done in the usual $\overline{MS}$ scheme and in another one, called $\overline{MS_p}$, which factorizes soft contributions and guarantees the axial current (non)conservation properties.
[ { "created": "Tue, 10 Oct 1995 20:00:13 GMT", "version": "v1" } ]
2009-10-28
[ [ "de Florian", "D.", "" ], [ "Canal", "C. A. Garcia", "" ], [ "Sassot", "R.", "" ] ]
We calculate and analize the ${\cal{O}}(\alpha_s)$ one-particle inclusive cross section in polarized deep inelastic lepton-hadron scattering, using dimensional regularization and the HVBM prescription for $\gamma_5$. We discuss the factorization of all the collinear singularities related to the process, particularly those which are absorbed in the redefinition of the spin dependent analogue of the recently introduced fracture functions. This is done in the usual $\overline{MS}$ scheme and in another one, called $\overline{MS_p}$, which factorizes soft contributions and guarantees the axial current (non)conservation properties.
1009.1099
Sally Dawson
S. Dawson and P. Jaiswal
Four Generations, Higgs Physics, and the MSSM
References added and minor typographical errors corrected
Phys.Rev.D82:073017,2010
10.1103/PhysRevD.82.073017
YITP-SB-10-30
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider the effects of a fourth generation of chiral fermions within the MSSM. Such a model offers the possibility of having the lightest neutral Higgs boson significantly heavier than in the three generation MSSM. The model is highly constrained by precision electroweak data, along with Higgs searches at the Tevatron. In addition, the requirements of perturbative unitarity and direct searches for heavy quarks imply that the four generation MSSM is only consistent for tan beta ~ 1 and highly tuned 4th generation fermion masses.
[ { "created": "Mon, 6 Sep 2010 17:29:14 GMT", "version": "v1" }, { "created": "Mon, 13 Sep 2010 20:28:19 GMT", "version": "v2" } ]
2010-11-08
[ [ "Dawson", "S.", "" ], [ "Jaiswal", "P.", "" ] ]
We consider the effects of a fourth generation of chiral fermions within the MSSM. Such a model offers the possibility of having the lightest neutral Higgs boson significantly heavier than in the three generation MSSM. The model is highly constrained by precision electroweak data, along with Higgs searches at the Tevatron. In addition, the requirements of perturbative unitarity and direct searches for heavy quarks imply that the four generation MSSM is only consistent for tan beta ~ 1 and highly tuned 4th generation fermion masses.
hep-ph/0508250
Martin Beneke
M. Beneke (RWTH Aachen), D. Yang (Nagoya U.)
Heavy-to-light B meson form factors at large recoil energy -- spectator-scattering corrections
55 pages, LaTeX, uses axodraw.sty
Nucl.Phys. B736 (2006) 34-81
10.1016/j.nuclphysb.2005.11.027
PITHA 05/10
hep-ph
null
We complete the investigation of loop corrections to hard spectator-scattering in exclusive B meson to light meson transitions by computing the short-distance coefficient (jet-function) from the hard-collinear scale. Adding together the two coefficients from matching QCD to SCET_I to SCET_II, we investigate the size of loop effects on the ratios of heavy-to-light meson form factors at large recoil. We find the corrections from the hard and hard-collinear scales to be of approximately the same size, and significant, but the perturbative expansions appear to be well-behaved. Our calculation provides a non-trivial verification of the factorization arguments. We observe considerable differences between the predictions based on factorization in the heavy-quark limit and current QCD sum rule calculations of the form factors. We also include the hard-collinear correction in the B -> pi pi tree amplitudes, and find an enhancement of the colour-suppressed amplitude relative to the colour-allowed amplitude.
[ { "created": "Wed, 24 Aug 2005 15:04:36 GMT", "version": "v1" } ]
2010-04-05
[ [ "Beneke", "M.", "", "RWTH Aachen" ], [ "Yang", "D.", "", "Nagoya U." ] ]
We complete the investigation of loop corrections to hard spectator-scattering in exclusive B meson to light meson transitions by computing the short-distance coefficient (jet-function) from the hard-collinear scale. Adding together the two coefficients from matching QCD to SCET_I to SCET_II, we investigate the size of loop effects on the ratios of heavy-to-light meson form factors at large recoil. We find the corrections from the hard and hard-collinear scales to be of approximately the same size, and significant, but the perturbative expansions appear to be well-behaved. Our calculation provides a non-trivial verification of the factorization arguments. We observe considerable differences between the predictions based on factorization in the heavy-quark limit and current QCD sum rule calculations of the form factors. We also include the hard-collinear correction in the B -> pi pi tree amplitudes, and find an enhancement of the colour-suppressed amplitude relative to the colour-allowed amplitude.
hep-ph/9403204
George Siopsis
D.B. DeLaney, S. Jadach, Ch. Shio, G. Siopsis, and B.F.L. Ward
Multiple Gluon Effects in Fermion--(Anti)Fermion Scattering at SSC/LHC Energies
12 pages + 4 figures (included), UTHEP-93-1001
Phys.Rev.D52:108-115,1995; Erratum-ibid.D66:019903,2002
10.1103/PhysRevD.52.108 10.1103/PhysRevD.66.019903
null
hep-ph
null
We extend the methods of Yennie, Frautschi and Suura (YFS) to compute, via Monte Carlo methods, the effects of multiple gluon emission in the processes $q+q'\to q''+q'''+n(G)$, where $G$ is a soft gluon. We show explicitly that the infrared singularities in the respective simulations are canceled to all orders in $\alpha_s$. Some discussion of this result from the standpoint of confinement is given. More importantly, we present, for the first time ever, sample numerical Monte Carlo data on multiple soft gluon emission in the rigorously extended YFS framework. We find that such soft gluon effects must be taken into account for precise SSC/LHC physics simulations.
[ { "created": "Tue, 1 Mar 1994 23:36:42 GMT", "version": "v1" } ]
2014-11-17
[ [ "DeLaney", "D. B.", "" ], [ "Jadach", "S.", "" ], [ "Shio", "Ch.", "" ], [ "Siopsis", "G.", "" ], [ "Ward", "B. F. L.", "" ] ]
We extend the methods of Yennie, Frautschi and Suura (YFS) to compute, via Monte Carlo methods, the effects of multiple gluon emission in the processes $q+q'\to q''+q'''+n(G)$, where $G$ is a soft gluon. We show explicitly that the infrared singularities in the respective simulations are canceled to all orders in $\alpha_s$. Some discussion of this result from the standpoint of confinement is given. More importantly, we present, for the first time ever, sample numerical Monte Carlo data on multiple soft gluon emission in the rigorously extended YFS framework. We find that such soft gluon effects must be taken into account for precise SSC/LHC physics simulations.
1405.0775
Yuya Yamaguchi
Tetsutaro Higaki, Tatsuo Kobayashi, Osamu Seto, and Yuya Yamaguchi
Axion monodromy inflation with multi-natural modulations
22 pages, 7 figures, version accepted for publication in JCAP: references and some comments added, and typos corrected
JCAP10 (2014) 025
10.1088/1475-7516/2014/10/025
KEK-TH-1732, EPHOU-14-010, HGU-CAP-034
hep-ph astro-ph.CO hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study parameter space in the axion monodromy inflation corrected by dynamically generated terms involving with the axion. The potential has the linear potential with multiple sinusoidal functions, which play a role in generating modulations. We show that this potential leads both to a large tensor-to-scalar ratio $r_T \sim 0.16$ and to a large negative running of spectral index $\alpha_s \sim - (0.02 -0.03)$. To realize these results, a small hierarchy among dynamical scales is required whereas the decay constants in sinusoidal functions remain sub-Planckian in this model. We discuss also reheating process after the inflation in a bottom-up approach.
[ { "created": "Mon, 5 May 2014 03:54:24 GMT", "version": "v1" }, { "created": "Wed, 12 Nov 2014 09:54:48 GMT", "version": "v2" } ]
2014-11-13
[ [ "Higaki", "Tetsutaro", "" ], [ "Kobayashi", "Tatsuo", "" ], [ "Seto", "Osamu", "" ], [ "Yamaguchi", "Yuya", "" ] ]
We study parameter space in the axion monodromy inflation corrected by dynamically generated terms involving with the axion. The potential has the linear potential with multiple sinusoidal functions, which play a role in generating modulations. We show that this potential leads both to a large tensor-to-scalar ratio $r_T \sim 0.16$ and to a large negative running of spectral index $\alpha_s \sim - (0.02 -0.03)$. To realize these results, a small hierarchy among dynamical scales is required whereas the decay constants in sinusoidal functions remain sub-Planckian in this model. We discuss also reheating process after the inflation in a bottom-up approach.
0904.1794
Hong-Hao Zhang
Hong-Hao Zhang, Kai-Xi Feng, Shao-Zhou Jiang, Qing Wang
Derivation of Electroweak Chiral Lagrangian from One Family Technicolor Model
6 pages
Mod.Phys.Lett.A24:693-702,2009
10.1142/S0217732309028229
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Based on previous studies deriving the chiral Lagrangian for pseudo scalar mesons from the first principle of QCD in the path integral formalism, we derive the electroweak chiral Lagrangian and dynamically compute all its coefficients from the one family technicolor model. The numerical results of the $p^4$ order coefficients obtained in this paper are proportional to the technicolor number $N_{\rm TC}$ and the technifermion number $N_{\rm TF}$, which agrees with the arguments in previous works, and which confirms the reliability of this dynamical computation.
[ { "created": "Mon, 13 Apr 2009 13:47:27 GMT", "version": "v1" } ]
2010-11-11
[ [ "Zhang", "Hong-Hao", "" ], [ "Feng", "Kai-Xi", "" ], [ "Jiang", "Shao-Zhou", "" ], [ "Wang", "Qing", "" ] ]
Based on previous studies deriving the chiral Lagrangian for pseudo scalar mesons from the first principle of QCD in the path integral formalism, we derive the electroweak chiral Lagrangian and dynamically compute all its coefficients from the one family technicolor model. The numerical results of the $p^4$ order coefficients obtained in this paper are proportional to the technicolor number $N_{\rm TC}$ and the technifermion number $N_{\rm TF}$, which agrees with the arguments in previous works, and which confirms the reliability of this dynamical computation.
hep-ph/0208094
Xin-Nian Wang
Xin-Nian Wang
Modified Fragmentation Function and Jet Quenching at RHIC
Invited talk at International Symposium on Statistical QCD, Bielefeld, Germany, 26-30 Aug 2001; 11 pages with 6 postscript figures
Nucl.Phys.A702:238,2002
10.1016/S0375-9474(02)00711-X
LBNL-51282
hep-ph nucl-th
null
Medium modification of jet fragmentation functions and parton energy loss in cold and hot matter are reviewed. The predicted nuclear modification of the jet fragmentation function agrees well with the recent HERMES data with a resultant energy loss dE/dx approximately 0.5 GeV/fm. From the the recent PHENIX data of high p_T pi_0 spectra in central Au+Au collisions at sqrt(s)=130 GeV, one extracts an energy loss for a 10 GeV parton that is equivalent to dE/dx=7.3 GeV/fm in a static medium with the same gluon density as in the initial stage of the collision at tau_0=0.2 fm/c. Constraints on jet quenching by the central rapidity density of charged hadrons is also discussed.
[ { "created": "Fri, 9 Aug 2002 19:27:45 GMT", "version": "v1" }, { "created": "Fri, 9 Aug 2002 20:12:01 GMT", "version": "v2" } ]
2014-11-17
[ [ "Wang", "Xin-Nian", "" ] ]
Medium modification of jet fragmentation functions and parton energy loss in cold and hot matter are reviewed. The predicted nuclear modification of the jet fragmentation function agrees well with the recent HERMES data with a resultant energy loss dE/dx approximately 0.5 GeV/fm. From the the recent PHENIX data of high p_T pi_0 spectra in central Au+Au collisions at sqrt(s)=130 GeV, one extracts an energy loss for a 10 GeV parton that is equivalent to dE/dx=7.3 GeV/fm in a static medium with the same gluon density as in the initial stage of the collision at tau_0=0.2 fm/c. Constraints on jet quenching by the central rapidity density of charged hadrons is also discussed.
1710.07269
Eisuke Sonomoto
Masahiro Kawasaki, Eisuke Sonomoto
Domain wall and isocurvature perturbation problems in a supersymmetric axion model
11 pages, 6 figures, LaTeX; explanations about SUSY axion models added
Phys. Rev. D 97, 083507 (2018)
10.1103/PhysRevD.97.083507
IPMU17-0142
hep-ph astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The axion causes two serious cosmological problems, domain wall and isocurvature perturbation problems. Linde pointed that the isocurvature perturbations are suppressed when the Peccei-Quinn (PQ) scalar field takes a large value $\sim M_{\text{pl}}$ (Planck scale) during inflation. In this case, however, the PQ field with large amplitude starts to oscillate after inflation and large fluctuations of the PQ field are produced through parametric resonance, which leads to the formation of domain walls. We consider a supersymmetric axion model and examine whether domain walls are formed by using lattice simulation. It is found that the domain wall problem does not appear in the SUSY axion model when the initial value of the PQ field is less than $10^{3}\times v$ where $v$ is the PQ symmetry breaking scale.
[ { "created": "Thu, 19 Oct 2017 17:53:11 GMT", "version": "v1" }, { "created": "Wed, 18 Sep 2019 07:23:01 GMT", "version": "v2" } ]
2019-09-19
[ [ "Kawasaki", "Masahiro", "" ], [ "Sonomoto", "Eisuke", "" ] ]
The axion causes two serious cosmological problems, domain wall and isocurvature perturbation problems. Linde pointed that the isocurvature perturbations are suppressed when the Peccei-Quinn (PQ) scalar field takes a large value $\sim M_{\text{pl}}$ (Planck scale) during inflation. In this case, however, the PQ field with large amplitude starts to oscillate after inflation and large fluctuations of the PQ field are produced through parametric resonance, which leads to the formation of domain walls. We consider a supersymmetric axion model and examine whether domain walls are formed by using lattice simulation. It is found that the domain wall problem does not appear in the SUSY axion model when the initial value of the PQ field is less than $10^{3}\times v$ where $v$ is the PQ symmetry breaking scale.
hep-ph/0108171
Shinta Kasuya
S. Kasuya, M. Kawasaki, and Fuminobu Takahashi
On the Moduli Problem and Baryogenesis in Gauge-mediated SUSY Breaking Models
11 pages, RevTeX, 5 postscript figures included
Phys.Rev. D65 (2002) 063509
10.1103/PhysRevD.65.063509
null
hep-ph
null
We investigate whether the Affleck-Dine mechanism can produce sufficient baryon number of the universe in the gauge-mediated SUSY breaking models, while evading the cosmological moduli problem by late-time entropy production. We find that the Q-ball formation renders the scenario very difficult to work, irrespective of the detail mechanism of the entropy production.
[ { "created": "Wed, 22 Aug 2001 04:18:08 GMT", "version": "v1" } ]
2009-11-07
[ [ "Kasuya", "S.", "" ], [ "Kawasaki", "M.", "" ], [ "Takahashi", "Fuminobu", "" ] ]
We investigate whether the Affleck-Dine mechanism can produce sufficient baryon number of the universe in the gauge-mediated SUSY breaking models, while evading the cosmological moduli problem by late-time entropy production. We find that the Q-ball formation renders the scenario very difficult to work, irrespective of the detail mechanism of the entropy production.
hep-ph/0109052
Thomas Schaefer
Thomas Schaefer (SUNY Stony Brook and RIKEN-BNL)
Mass Terms in Effective Theories of High Density Quark Matter
22 pages, 4 figures
Phys.Rev. D65 (2002) 074006
10.1103/PhysRevD.65.074006
null
hep-ph
null
We study the structure of mass terms in the effective theory for quasi-particles in QCD at high baryon density. To next-to-leading order in the $1/p_F$ expansion we find two types of mass terms, chirality conserving two-fermion operators and chirality violating four-fermion operators. In the effective chiral theory for Goldstone modes in the color-flavor-locked (CFL) phase the former terms correspond to effective chemical potentials, while the latter lead to Lorentz invariant mass terms. We compute the masses of Goldstone bosons in the CFL phase, confirming earlier results by Son and Stephanov as well as Bedaque and Sch\"afer. We show that to leading order in the coupling constant $g$ there is no anti-particle gap contribution to the mass of Goldstone modes, and that our results are independent of the choice of gauge.
[ { "created": "Thu, 6 Sep 2001 21:05:38 GMT", "version": "v1" } ]
2009-11-07
[ [ "Schaefer", "Thomas", "", "SUNY Stony Brook and RIKEN-BNL" ] ]
We study the structure of mass terms in the effective theory for quasi-particles in QCD at high baryon density. To next-to-leading order in the $1/p_F$ expansion we find two types of mass terms, chirality conserving two-fermion operators and chirality violating four-fermion operators. In the effective chiral theory for Goldstone modes in the color-flavor-locked (CFL) phase the former terms correspond to effective chemical potentials, while the latter lead to Lorentz invariant mass terms. We compute the masses of Goldstone bosons in the CFL phase, confirming earlier results by Son and Stephanov as well as Bedaque and Sch\"afer. We show that to leading order in the coupling constant $g$ there is no anti-particle gap contribution to the mass of Goldstone modes, and that our results are independent of the choice of gauge.
2208.14910
Philine van Vliet
Kristof De Bruyn, Robert Fleischer, Eleftheria Malami and Philine van Vliet
New Physics in $B_q^0-\bar B_q^0$ Mixing: Present Challenges, Prospects, and Implications for $B_q^0\to\mu^+\mu^-$
45 pages, 14 figures and 6 tables. This version matches the published version
null
10.1088/1361-6471/acab1d
Nikhef-2022-012
hep-ph hep-ex
http://creativecommons.org/licenses/by/4.0/
The phenomenon of $B^0_q-\bar B^0_q$ mixing ($q=d,s$) provides a sensitive probe for physics beyond the Standard Model. We explore the corresponding space for New Physics left through the current data, having a careful look at analyses of the Unitarity Triangle that are needed for the Standard Model predictions of the $B_q$ mixing parameters. In particular, we explore the impact of tensions between inclusive and exclusive determinations of the CKM matrix elements $|V_{ub}|$ and $|V_{cb}|$. Moreover, we focus on the angle $\gamma$ of the Unitarity Triangle, comparing measurements from $B\to DK$ and $B\to\pi\pi$, $\rho\pi$, $\rho\rho$ decays, where the latter are typically interpreted in terms of the angle $\alpha$. We discuss various scenarios and present the corresponding state-of-the-art constraints on the New Physics parameters of $B_q^0-\bar B_q^0$ mixing. We point out that these results have an interesting application in the analysis of rare $B_q^0\to \mu^+\mu^-$ decays, allowing us to minimise the impact of CKM parameters in the search for New Physics. In view of the high-precision era, we make future projections. Interestingly, we find that for the extraction of the New Physics parameters in the $B_d$ system the determination of the apex of the Unitarity Triangle results in a key limiting factor. By contrast, the corresponding impact is negligible for the $B_s$ system, making it a promising candidate to reveal sources of New Physics.
[ { "created": "Wed, 31 Aug 2022 15:11:52 GMT", "version": "v1" }, { "created": "Thu, 8 Sep 2022 14:48:19 GMT", "version": "v2" }, { "created": "Wed, 15 Mar 2023 14:15:03 GMT", "version": "v3" } ]
2023-03-16
[ [ "De Bruyn", "Kristof", "" ], [ "Fleischer", "Robert", "" ], [ "Malami", "Eleftheria", "" ], [ "van Vliet", "Philine", "" ] ]
The phenomenon of $B^0_q-\bar B^0_q$ mixing ($q=d,s$) provides a sensitive probe for physics beyond the Standard Model. We explore the corresponding space for New Physics left through the current data, having a careful look at analyses of the Unitarity Triangle that are needed for the Standard Model predictions of the $B_q$ mixing parameters. In particular, we explore the impact of tensions between inclusive and exclusive determinations of the CKM matrix elements $|V_{ub}|$ and $|V_{cb}|$. Moreover, we focus on the angle $\gamma$ of the Unitarity Triangle, comparing measurements from $B\to DK$ and $B\to\pi\pi$, $\rho\pi$, $\rho\rho$ decays, where the latter are typically interpreted in terms of the angle $\alpha$. We discuss various scenarios and present the corresponding state-of-the-art constraints on the New Physics parameters of $B_q^0-\bar B_q^0$ mixing. We point out that these results have an interesting application in the analysis of rare $B_q^0\to \mu^+\mu^-$ decays, allowing us to minimise the impact of CKM parameters in the search for New Physics. In view of the high-precision era, we make future projections. Interestingly, we find that for the extraction of the New Physics parameters in the $B_d$ system the determination of the apex of the Unitarity Triangle results in a key limiting factor. By contrast, the corresponding impact is negligible for the $B_s$ system, making it a promising candidate to reveal sources of New Physics.
1702.00943
Ara Ioannisian Dr.
A. Ioannisian, N. Kazarian
Transition Radiation by Neutrinos at an Edge of Magnetic Field
4 pages, 1 figure. arXiv admin note: substantial text overlap with arXiv:1105.0620, arXiv:hep-ph/9612285
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We calculate the transition radiation process $\nu \to \nu \gamma$ at an interface of magnetic field and vacuum. The neutrinos are taken to be with only standard-model couplings. The magnetic field fulfills the dual purpose of inducing an effective neutrino-photon vertex and of modifying the photon dispersion relation. The transition radiation occurs when at least one of those quantities have different values in different media. The neutrino mass is ignored due to its negligible contribution. We present a result for the probability of the transition radiation which is both accurate and analytic.
[ { "created": "Fri, 3 Feb 2017 09:37:38 GMT", "version": "v1" } ]
2017-02-06
[ [ "Ioannisian", "A.", "" ], [ "Kazarian", "N.", "" ] ]
We calculate the transition radiation process $\nu \to \nu \gamma$ at an interface of magnetic field and vacuum. The neutrinos are taken to be with only standard-model couplings. The magnetic field fulfills the dual purpose of inducing an effective neutrino-photon vertex and of modifying the photon dispersion relation. The transition radiation occurs when at least one of those quantities have different values in different media. The neutrino mass is ignored due to its negligible contribution. We present a result for the probability of the transition radiation which is both accurate and analytic.
0903.4420
Vasiliy Rodionov
V.N.Rodionov
The Maximal Mass Model and Lepton Magnetic Moment
10 pages, 0 figures
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The two-component formulation of quantum electrodynamics with fundamental mass is studied. We review and update the prediction of the primordial existence of lepton magnetic moment in framework of two component formulation of the Maximal Mass Model containing a limiting mass $M$, which is considered as new universal physical constant. As it well known in the Dirac theory so-called gyromagnetic factor $g=2$. Quantum electrodynamics together with electro-weak theory and hadronic contributions predicts deviations from Dirac's value. It is very important that all these effects \textbf{slightly increase the $g$-value}. But in our model we have any decreasing of this quantity $g=2\sqrt{1-m^2/M^2}$, where $m$ - is a lepton mass. The most intriguing prediction of new approach is the absolute value of this deviation increases with growth of a lepton mass. In this connection the direct experimental measurements of $\tau$ - lepton anomalous magnetic moment $a_\tau = (g - 2)/2$ gain in extraordinary importance. The most stringent limit $-0.052 < a_{\tau} < 0.013$ at 95% confidence level, was set by the {\small DELPHI}\cite{delphi} collaboration. The authors also quote their result in the form of central value and error $ a_\tau = - 0.018(17).$ To pay attention that the sign of $a_\tau$ is the negative and now we can speak about a qualitative agreement with our predictions.
[ { "created": "Wed, 25 Mar 2009 18:43:37 GMT", "version": "v1" } ]
2009-03-26
[ [ "Rodionov", "V. N.", "" ] ]
The two-component formulation of quantum electrodynamics with fundamental mass is studied. We review and update the prediction of the primordial existence of lepton magnetic moment in framework of two component formulation of the Maximal Mass Model containing a limiting mass $M$, which is considered as new universal physical constant. As it well known in the Dirac theory so-called gyromagnetic factor $g=2$. Quantum electrodynamics together with electro-weak theory and hadronic contributions predicts deviations from Dirac's value. It is very important that all these effects \textbf{slightly increase the $g$-value}. But in our model we have any decreasing of this quantity $g=2\sqrt{1-m^2/M^2}$, where $m$ - is a lepton mass. The most intriguing prediction of new approach is the absolute value of this deviation increases with growth of a lepton mass. In this connection the direct experimental measurements of $\tau$ - lepton anomalous magnetic moment $a_\tau = (g - 2)/2$ gain in extraordinary importance. The most stringent limit $-0.052 < a_{\tau} < 0.013$ at 95% confidence level, was set by the {\small DELPHI}\cite{delphi} collaboration. The authors also quote their result in the form of central value and error $ a_\tau = - 0.018(17).$ To pay attention that the sign of $a_\tau$ is the negative and now we can speak about a qualitative agreement with our predictions.
hep-ph/0510412
M. N. Rebelo
Gustavo C. Branco, M. N. Rebelo, J. I. Silva-Marcos
Leptogenesis, Yukawa Textures and Weak Basis Invariants
16 pages, no figures. One reference added, version submitted for publication
Phys.Lett. B633 (2006) 345-354
10.1016/j.physletb.2005.11.067
TUM-HEP-605/05, MPP-2005-127
hep-ph
null
We show that a large class of sets of leptonic texture zeros considered in the literature imply the vanishing of certain CP-odd weak-basis invariants. These invariant conditions enable one to recognize a flavour model corresponding to a set of texture zeros, when written in an arbitrary weak-basis where the zeros are not manifest. We also analyse the r\^ ole of texture zeros in allowing for a connection between leptogenesis and low-energy leptonic masses, mixing and CP violation. For some of the textures the variables relevant for leptogenesis can be fully determined in terms of low energy parameters and heavy neutrino masses.
[ { "created": "Mon, 31 Oct 2005 14:07:13 GMT", "version": "v1" }, { "created": "Tue, 15 Nov 2005 14:21:40 GMT", "version": "v2" } ]
2009-11-11
[ [ "Branco", "Gustavo C.", "" ], [ "Rebelo", "M. N.", "" ], [ "Silva-Marcos", "J. I.", "" ] ]
We show that a large class of sets of leptonic texture zeros considered in the literature imply the vanishing of certain CP-odd weak-basis invariants. These invariant conditions enable one to recognize a flavour model corresponding to a set of texture zeros, when written in an arbitrary weak-basis where the zeros are not manifest. We also analyse the r\^ ole of texture zeros in allowing for a connection between leptogenesis and low-energy leptonic masses, mixing and CP violation. For some of the textures the variables relevant for leptogenesis can be fully determined in terms of low energy parameters and heavy neutrino masses.
hep-ph/0301207
Pasquale Migliozzi
G. De Lellis, P.Migliozzi, P. Strolin
Heavy quark studies with nuclear emulsions
To be published on the book for the eightieth birthday of Roberto Salmeron, World Scientific
null
null
null
hep-ph
null
Emulsions have started particle physics with the discovery of natural radioactivity by Becquerel in 1896. The development of the ``nuclear emulsions'' made it possible to detect tracks of single particle and to perform detailed measurements of their interactions. The discovery of the pion in 1947 was the first, spectacular demonstration of their unique features for the direct observation of the production and decay of short-lived particles, with negligible or very low background. In particular, these features are now exploited for studies of heavy quark physics in experiments where nuclear emulsions are combined with electronic detectors and profit is taken of the remarkable technological progress in automated analysis. In these experiments, neutrinos provide a selective probe for specific quark flavors. Interesting results on charm production and decay are expected in the very near future.
[ { "created": "Thu, 23 Jan 2003 18:16:52 GMT", "version": "v1" } ]
2007-05-23
[ [ "De Lellis", "G.", "" ], [ "Migliozzi", "P.", "" ], [ "Strolin", "P.", "" ] ]
Emulsions have started particle physics with the discovery of natural radioactivity by Becquerel in 1896. The development of the ``nuclear emulsions'' made it possible to detect tracks of single particle and to perform detailed measurements of their interactions. The discovery of the pion in 1947 was the first, spectacular demonstration of their unique features for the direct observation of the production and decay of short-lived particles, with negligible or very low background. In particular, these features are now exploited for studies of heavy quark physics in experiments where nuclear emulsions are combined with electronic detectors and profit is taken of the remarkable technological progress in automated analysis. In these experiments, neutrinos provide a selective probe for specific quark flavors. Interesting results on charm production and decay are expected in the very near future.
hep-ph/0104247
John Gracey
A.G.M. Pickering, J.A. Gracey and D.R.T. Jones
Three loop gauge beta-function for the most general single gauge-coupling theory
10 latex pages
Phys.Lett. B510 (2001) 347-354; Phys.Lett. B512 (2001) 230-238
10.1016/S0370-2693(01)00718-3
IUHET 434, LTH 498
hep-ph hep-th
null
We calculate the three loop contribution to the beta-function of the gauge coupling constant in a general, anomaly-free, renormalisable gauge field theory involving a single gauge coupling using the background field method in the MSbar scheme.
[ { "created": "Tue, 24 Apr 2001 15:27:39 GMT", "version": "v1" } ]
2009-11-07
[ [ "Pickering", "A. G. M.", "" ], [ "Gracey", "J. A.", "" ], [ "Jones", "D. R. T.", "" ] ]
We calculate the three loop contribution to the beta-function of the gauge coupling constant in a general, anomaly-free, renormalisable gauge field theory involving a single gauge coupling using the background field method in the MSbar scheme.
hep-ph/9501379
Ed Stoeffhaas
V. Barger, Kingman Cheung, T. Han and R.J.N.Phillips
Probing Strongly-interacting Electroweak Dynamics through $W^+W^-/ZZ$ Ratios at Future $e^+e^-$ Colliders
Standard Latex, 24 pages, 8 postscript figures included (uufiled). Compressed postscript version with figures can be obtained at ftp://phenom.physics.wisc.edu/pub/preprints/1995/madph-95-865.ps.Z or at http://phenom.physics.wisc.edu/pub/preprints/1995/madph-95-865.ps.Z
Phys.Rev.D52:3815-3825,1995
10.1103/PhysRevD.52.3815
MADPH-95-865
hep-ph
null
We point out that the ratio of $W^+ W^- \to W^+ W^-$ and $W^+W^- \to ZZ$ cross sections is a sensitive probe of the dynamics of electroweak symmetry breaking, in the CM energy region $\sqrt {s_{\rm ww}^{}} \agt 1$~TeV where vector boson scattering may well become strong. We suggest ways in which this ratio can be extracted at a 1.5 TeV $e^+e^-$ linear collider, using $W^\pm,Z \to jj$ hadronic decays and relying on dijet mass resolution to provide statistical discrimination between $W^\pm$ and $Z$. $WW$ fusion processes studied here are unique for exploring scalar resonances of mass about 1 TeV and are complementary to studies via the direct channel $e^+ e^- \rightarrow W^+W^-$ for the vector and non-resonant cases. With an integrated luminosity of 200 fb$^{-1}$, the signals obtained are statistically significant. Comparison with a study of $e^-e^- \rightarrow \nu\nu W^-W^-$ process is made. Enhancements of the signal rate from using a polarized electron beam, or at a 2 TeV $e^+e^-$ linear collider and possible higher energy $\mu^+\mu^-$ colliders, are also presented.
[ { "created": "Wed, 25 Jan 1995 22:33:00 GMT", "version": "v1" } ]
2016-09-01
[ [ "Barger", "V.", "" ], [ "Cheung", "Kingman", "" ], [ "Han", "T.", "" ], [ "Phillips", "R. J. N.", "" ] ]
We point out that the ratio of $W^+ W^- \to W^+ W^-$ and $W^+W^- \to ZZ$ cross sections is a sensitive probe of the dynamics of electroweak symmetry breaking, in the CM energy region $\sqrt {s_{\rm ww}^{}} \agt 1$~TeV where vector boson scattering may well become strong. We suggest ways in which this ratio can be extracted at a 1.5 TeV $e^+e^-$ linear collider, using $W^\pm,Z \to jj$ hadronic decays and relying on dijet mass resolution to provide statistical discrimination between $W^\pm$ and $Z$. $WW$ fusion processes studied here are unique for exploring scalar resonances of mass about 1 TeV and are complementary to studies via the direct channel $e^+ e^- \rightarrow W^+W^-$ for the vector and non-resonant cases. With an integrated luminosity of 200 fb$^{-1}$, the signals obtained are statistically significant. Comparison with a study of $e^-e^- \rightarrow \nu\nu W^-W^-$ process is made. Enhancements of the signal rate from using a polarized electron beam, or at a 2 TeV $e^+e^-$ linear collider and possible higher energy $\mu^+\mu^-$ colliders, are also presented.
hep-ph/9906393
Andre Martin
Andr\'e Martin
The rigorous analyticity-unitarity program and its successes
10 pages latex
Lect.Notes Phys.558:127-135,2000
null
CERN-TH/99-110
hep-ph
null
We show how the combination of analyticity properties derived from local field theory and the unitarity condition (in particular positivity) leads to non-trivial physical results, including the proof of the "Froissart bound" from first principles and the existence of absolute bounds on the pion-pion scattering amplitude.
[ { "created": "Wed, 16 Jun 1999 13:32:50 GMT", "version": "v1" } ]
2011-07-19
[ [ "Martin", "André", "" ] ]
We show how the combination of analyticity properties derived from local field theory and the unitarity condition (in particular positivity) leads to non-trivial physical results, including the proof of the "Froissart bound" from first principles and the existence of absolute bounds on the pion-pion scattering amplitude.
2206.14445
David A. Kosower
David A. Kosower, Sebastian P\"ogel
A Unitarity Approach to Two-Loop All-Plus Rational Terms
108 pages, 41 figures
null
null
SAGEX-22-26-E, MITP-22-040
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a calculation of the rational terms in two-loop all-plus gluon amplitudes using $D$-dimensional unitarity. We use a conjecture of separability of the two loops, and then a simple generalization of one-loop $D$-dimensional unitarity to perform calculations. We compute the four- and five-point rational terms analytically, and the six- and seven-point ones numerically. We find agreement with previous calculations of Dalgleish, Dunbar, Godwin, Jehu, Perkins, and Strong. For a special subleading-color amplitude, we compute the eight- and nine-point results numerically, and find agreement with an all-$n$ conjecture of Dunbar, Perkins, and Strong.
[ { "created": "Wed, 29 Jun 2022 07:51:31 GMT", "version": "v1" } ]
2022-06-30
[ [ "Kosower", "David A.", "" ], [ "Pögel", "Sebastian", "" ] ]
We present a calculation of the rational terms in two-loop all-plus gluon amplitudes using $D$-dimensional unitarity. We use a conjecture of separability of the two loops, and then a simple generalization of one-loop $D$-dimensional unitarity to perform calculations. We compute the four- and five-point rational terms analytically, and the six- and seven-point ones numerically. We find agreement with previous calculations of Dalgleish, Dunbar, Godwin, Jehu, Perkins, and Strong. For a special subleading-color amplitude, we compute the eight- and nine-point results numerically, and find agreement with an all-$n$ conjecture of Dunbar, Perkins, and Strong.
1901.02836
Narinder Kumar
Narinder Kumar
Transverse densities and generalized parton distributions of $\rho$ meson in light front quark model
18 pages, 08 figures, To appear in Physical Review D
Phys. Rev. D 99, 014039 (2019)
10.1103/PhysRevD.99.014039
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
We have investigated the transverse charge density for longitudinal and transversely polarized $\rho$ meson in light-front quark model (LFQM). Charge densities are obtained from the elastic form factors of the $\rho$ meson calculated in LFQM including the zero-mode contributions. We have computed the different helicity matrix elements of the $\rho$ meson. In addition to this, we have also presented the results for the generalized parton distributions (GPDs) and impact-parameter dependent parton distribution functions (ipdpdfs) of the $\rho$ meson.
[ { "created": "Wed, 9 Jan 2019 17:17:51 GMT", "version": "v1" } ]
2019-02-06
[ [ "Kumar", "Narinder", "" ] ]
We have investigated the transverse charge density for longitudinal and transversely polarized $\rho$ meson in light-front quark model (LFQM). Charge densities are obtained from the elastic form factors of the $\rho$ meson calculated in LFQM including the zero-mode contributions. We have computed the different helicity matrix elements of the $\rho$ meson. In addition to this, we have also presented the results for the generalized parton distributions (GPDs) and impact-parameter dependent parton distribution functions (ipdpdfs) of the $\rho$ meson.
2309.06964
Shota Nakagawa
Shota Nakagawa, Yuichiro Nakai, Masaki Yamada, and Yufei Zhang
Dynamics of Superconformal Axion: Quality and Scalegenesis
8 pages, 3 figures
Phys.Lett.B 849 (2024) 138447
10.1016/j.physletb.2024.138447
TU-1210
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We explore a dynamical mechanism to realize the emergence of a global $U(1)_{\rm PQ}$ symmetry and its spontaneous breaking at an intermediate scale for an axion solution to the strong CP problem. Such a dynamics is provided by a new supersymmetric QCD near the middle of conformal window that couples to fields spontaneously breaking the $U(1)_{\rm PQ}$ symmetry. A large anomalous dimension of the $U(1)_{\rm PQ}$ breaking fields leads to the suppression of explicit $U(1)_{\rm PQ}$-violating higher dimensional operators. The $U(1)_{\rm PQ}$ breaking vacuum is generated at a scale hierarchically smaller than the Planck scale by a non-perturbative effect. The $U(1)_{\rm PQ}$ breaking drives the conformal breaking, and all the new quarks become massive. The axion potential is generated by the ordinary color $SU(3)_C$ effect as the $U(1)_{\rm PQ}$ symmetry is only anomalous under the $SU(3)_C$. The saxion direction is stabilized by supersymmetry breaking and cosmologically harmless.
[ { "created": "Wed, 13 Sep 2023 13:59:17 GMT", "version": "v1" }, { "created": "Tue, 30 Jan 2024 13:10:59 GMT", "version": "v2" } ]
2024-01-31
[ [ "Nakagawa", "Shota", "" ], [ "Nakai", "Yuichiro", "" ], [ "Yamada", "Masaki", "" ], [ "Zhang", "Yufei", "" ] ]
We explore a dynamical mechanism to realize the emergence of a global $U(1)_{\rm PQ}$ symmetry and its spontaneous breaking at an intermediate scale for an axion solution to the strong CP problem. Such a dynamics is provided by a new supersymmetric QCD near the middle of conformal window that couples to fields spontaneously breaking the $U(1)_{\rm PQ}$ symmetry. A large anomalous dimension of the $U(1)_{\rm PQ}$ breaking fields leads to the suppression of explicit $U(1)_{\rm PQ}$-violating higher dimensional operators. The $U(1)_{\rm PQ}$ breaking vacuum is generated at a scale hierarchically smaller than the Planck scale by a non-perturbative effect. The $U(1)_{\rm PQ}$ breaking drives the conformal breaking, and all the new quarks become massive. The axion potential is generated by the ordinary color $SU(3)_C$ effect as the $U(1)_{\rm PQ}$ symmetry is only anomalous under the $SU(3)_C$. The saxion direction is stabilized by supersymmetry breaking and cosmologically harmless.
hep-ph/0007015
Christophe Ringeval
Christophe Ringeval
Equation of state of cosmic strings with fermionic current-carriers
30 pages, 15 figures, uses ReVTeX, equation of state corrected, comments and references added. Accepted for publication in Phys. Rev. D
Phys.Rev. D63 (2001) 063508
10.1103/PhysRevD.63.063508
null
hep-ph astro-ph gr-qc
null
The relevant characteristic features, including energy per unit length and tension, of a cosmic string carrying massless fermionic currents in the framework of the Witten model in the neutral limit are derived through quantization of the spinor fields along the string. The construction of a Fock space is performed by means of a separation between longitudinal modes and the so-called transverse zero energy solutions of the Dirac equation in the vortex. As a result, quantization leads to a set of naturally defined state parameters which are the number densities of particles and anti-particles trapped in the cosmic string. It is seen that the usual one-parameter formalism for describing the macroscopic dynamics of current-carrying vortices is not sufficient in the case of fermionic carriers.
[ { "created": "Mon, 3 Jul 2000 16:18:41 GMT", "version": "v1" }, { "created": "Thu, 14 Dec 2000 17:30:44 GMT", "version": "v2" } ]
2009-10-31
[ [ "Ringeval", "Christophe", "" ] ]
The relevant characteristic features, including energy per unit length and tension, of a cosmic string carrying massless fermionic currents in the framework of the Witten model in the neutral limit are derived through quantization of the spinor fields along the string. The construction of a Fock space is performed by means of a separation between longitudinal modes and the so-called transverse zero energy solutions of the Dirac equation in the vortex. As a result, quantization leads to a set of naturally defined state parameters which are the number densities of particles and anti-particles trapped in the cosmic string. It is seen that the usual one-parameter formalism for describing the macroscopic dynamics of current-carrying vortices is not sufficient in the case of fermionic carriers.
1101.5377
Georges Grunberg
Georges Grunberg
On threshold resummation of singlet structure and fragmentation functions
29 pages, no figure, v2: inappropriate statements on the normalization of the timelike gluon coefficient function removed; new section added to deal with the large-x behavior of the P_{gq}(x) splitting function, v3: a few stylistic changes; to be published in Nuclear Physics B
null
10.1016/j.nuclphysb.2011.05.008
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The large-x behavior of the physical evolution kernels appearing in the second order evolution equations of the singlet F_2 structure function and of the F_{phi} structure function in phi-exchange DIS is investigated. The validity of a leading logarithmic threshold resummation, analogous to the one prevailing for the non-singlet physical kernels, is established, allowing to recover the predictions of Soar et al. for the double-logarithmic contributions (ln^i(1-x), i=4,5,6) to the four loop splitting function P^{(3)}_{qg}(x) and P^{(3)}_{gq}(x). Threshold resummation at the next-to-leading logarithmic level is found however to break down in the three loop kernels, except in the "supersymmetric" case C_A=C_F. Assuming a full threshold resummation does hold in this case also beyond three loop gives some information on the leading and next-to-leading single-logarithmic contributions (ln^i(1-x), i=2,3) to P^{(3)}_{qg}(x) and P^{(3)}_{gq}(x). Similar results are obtained for singlet fragmentation functions in e^+e^- annihilation up to two loop, where a large-x Gribov-Lipatov relation in the physical kernels is pointed out. Assuming this relation also holds at three loop, one gets predictions for all large-x logarithmic contributions to the three loop timelike splitting function P^{(2)T}_{gq}(x), which are related to similar terms in P^{(2)}_{qg}(x).
[ { "created": "Thu, 27 Jan 2011 20:09:34 GMT", "version": "v1" }, { "created": "Wed, 6 Apr 2011 20:13:57 GMT", "version": "v2" }, { "created": "Wed, 25 May 2011 10:16:22 GMT", "version": "v3" } ]
2015-05-27
[ [ "Grunberg", "Georges", "" ] ]
The large-x behavior of the physical evolution kernels appearing in the second order evolution equations of the singlet F_2 structure function and of the F_{phi} structure function in phi-exchange DIS is investigated. The validity of a leading logarithmic threshold resummation, analogous to the one prevailing for the non-singlet physical kernels, is established, allowing to recover the predictions of Soar et al. for the double-logarithmic contributions (ln^i(1-x), i=4,5,6) to the four loop splitting function P^{(3)}_{qg}(x) and P^{(3)}_{gq}(x). Threshold resummation at the next-to-leading logarithmic level is found however to break down in the three loop kernels, except in the "supersymmetric" case C_A=C_F. Assuming a full threshold resummation does hold in this case also beyond three loop gives some information on the leading and next-to-leading single-logarithmic contributions (ln^i(1-x), i=2,3) to P^{(3)}_{qg}(x) and P^{(3)}_{gq}(x). Similar results are obtained for singlet fragmentation functions in e^+e^- annihilation up to two loop, where a large-x Gribov-Lipatov relation in the physical kernels is pointed out. Assuming this relation also holds at three loop, one gets predictions for all large-x logarithmic contributions to the three loop timelike splitting function P^{(2)T}_{gq}(x), which are related to similar terms in P^{(2)}_{qg}(x).
hep-ph/9801371
Sergey Cherkas
V.G. Baryshevsky, K.G. Batrakov and S. Cherkas (Institute of Nuclear Problems, Minsk)
The effect of spin oscillation of relativistic particles passing through substance and the possibility of the constituent quark rescattering observation at omega-hyperon - proton collision
LaTeX, 21 pages with 4 figures, uses ioplppt.sty, iopl12.sty. Model of the inelastic corrections replaced
J.Phys.G24:2049-2064,1998
10.1088/0954-3899/24/11/007
NPI-98-04
hep-ph
null
For the omega-hyperon passing through matter the phenomena of spin rotation and oscillation has investigated quantitatively. Connection of these phenomena with constituent quark rescattering has been determined. It allows one to investigate quark rescattering directly without background of a single scattering.
[ { "created": "Wed, 21 Jan 1998 11:01:48 GMT", "version": "v1" }, { "created": "Mon, 6 Apr 1998 10:18:54 GMT", "version": "v2" } ]
2008-11-26
[ [ "Baryshevsky", "V. G.", "", "Institute of Nuclear\n Problems, Minsk" ], [ "Batrakov", "K. G.", "", "Institute of Nuclear\n Problems, Minsk" ], [ "Cherkas", "S.", "", "Institute of Nuclear\n Problems, Minsk" ] ]
For the omega-hyperon passing through matter the phenomena of spin rotation and oscillation has investigated quantitatively. Connection of these phenomena with constituent quark rescattering has been determined. It allows one to investigate quark rescattering directly without background of a single scattering.
hep-ph/0606027
Davron Matrasulov
D.U.Matrasulov, F.C.Khanna, Kh.T.Butanov and Kh.Yu.Rakhimov
Spectra of Quarkonia at Finite Temperature
12 pages, 1 figure. To appear Mod.Phys.Lett. A
Mod.Phys.Lett.A21:1383-1392,2006
10.1142/S0217732306020810
null
hep-ph
null
Finite-temperature spectra of heavy quarkonia are calculated by combining potential model and thermofield dynamics formalisms. The mass spectra of the heavy quarkonia with various quark contents are calculated. It is found that binding mass of the quarkonium decreases as temperature increases.
[ { "created": "Fri, 2 Jun 2006 08:34:23 GMT", "version": "v1" } ]
2010-01-26
[ [ "Matrasulov", "D. U.", "" ], [ "Khanna", "F. C.", "" ], [ "Butanov", "Kh. T.", "" ], [ "Rakhimov", "Kh. Yu.", "" ] ]
Finite-temperature spectra of heavy quarkonia are calculated by combining potential model and thermofield dynamics formalisms. The mass spectra of the heavy quarkonia with various quark contents are calculated. It is found that binding mass of the quarkonium decreases as temperature increases.
2203.16549
Xiaojian Du
Xiaojian Du, Michal P. Heller, S\"oren Schlichting, Viktor Svensson
Exponential Approach to the Hydrodynamic Attractor in Yang-Mills Kinetic Theory
12 pages, 7 figures
null
10.1103/PhysRevD.106.014016
null
hep-ph hep-th nucl-th
http://creativecommons.org/licenses/by/4.0/
We use principal component analysis to study the hydrodynamic attractor in Yang-Mills kinetic theory undergoing the Bjorken expansion with Color Glass Condensate initial conditions. The late time hydrodynamic attractor is characterized by a single principal component determining the overall energy scale. How it is reached is governed by the disappearance of single subleading principal component characterizing deviations of the pressure anisotropy, the screening mass and the scattering rate. We find that for wide range of couplings the approach to the hydrodynamic attractor at late times is well described by an exponential. Its decay rate dependence on the coupling turns out to translate into a simple dependence on the shear viscosity to entropy density ratio.
[ { "created": "Wed, 30 Mar 2022 18:00:01 GMT", "version": "v1" } ]
2022-08-31
[ [ "Du", "Xiaojian", "" ], [ "Heller", "Michal P.", "" ], [ "Schlichting", "Sören", "" ], [ "Svensson", "Viktor", "" ] ]
We use principal component analysis to study the hydrodynamic attractor in Yang-Mills kinetic theory undergoing the Bjorken expansion with Color Glass Condensate initial conditions. The late time hydrodynamic attractor is characterized by a single principal component determining the overall energy scale. How it is reached is governed by the disappearance of single subleading principal component characterizing deviations of the pressure anisotropy, the screening mass and the scattering rate. We find that for wide range of couplings the approach to the hydrodynamic attractor at late times is well described by an exponential. Its decay rate dependence on the coupling turns out to translate into a simple dependence on the shear viscosity to entropy density ratio.
hep-ph/9605298
Robert Peschanski
A.Bialas and R.Peschanski
Hard Diffraction From Quasi-Elastic Dipole Scattering
latex + now: 4 encapsulated poscript figures
Phys.Lett.B387:405-410,1996
10.1016/0370-2693(96)01018-0
TPJU-8/96 (Krakow), T 96/036 (Saclay), LPTHE 96/27 (Orsay)
hep-ph
null
The contribution to diffraction dissociation of virtual photons due to quasi-elastic scattering of the $q$-$\bar q$ component is calculated in the framework of the QCD dipole picture. Both longitudinal and transverse components of the cross-section are given. It is shown that, at fixed mass of the diffractively produced system, quantum mechanical interference plays an important r\^ ole. Phenomenological consequences are discussed.
[ { "created": "Tue, 14 May 1996 07:50:40 GMT", "version": "v1" }, { "created": "Thu, 23 May 1996 12:59:53 GMT", "version": "v2" } ]
2008-11-26
[ [ "Bialas", "A.", "" ], [ "Peschanski", "R.", "" ] ]
The contribution to diffraction dissociation of virtual photons due to quasi-elastic scattering of the $q$-$\bar q$ component is calculated in the framework of the QCD dipole picture. Both longitudinal and transverse components of the cross-section are given. It is shown that, at fixed mass of the diffractively produced system, quantum mechanical interference plays an important r\^ ole. Phenomenological consequences are discussed.
hep-ph/0606293
Gilad Perez
Kaustubh Agashe, Gilad Perez and Amarjit Soni
Collider Signals of Top Quark Flavor Violation from a Warped Extra Dimension
5 pages, references added, comment added regarding models with custodial symmetry for Z -> b \bar b
Phys.Rev.D75:015002,2007
10.1103/PhysRevD.75.015002
SU-4252-830, BNL-HET-06/4
hep-ph
null
We study top quark flavor violation in the framework of a warped extra dimension with the Standard Model (SM) fields propagating in the bulk. Such a scenario provides solutions to both the Planck-weak hierarchy problem and the flavor puzzle of the SM without inducing a flavor problem. We find that, generically, tcZ couplings receive a huge enhancement, in particular the right handed ones can be O(1%). This results in BR(t -> c Z) at or above the sensitivity of the Large Hadron Collider (LHC). At the International Linear Collider (ILC), single top production, via e^+ e^- -> t \bar c, can be a striking signal for this scenario. In particular, it represents a physics topic of critical importance that can be explored even with a relatively low energy option, close to the tc threshold. At both the LHC and the ILC, angular distributions can probe the above prediction of dominance of right-handed couplings.
[ { "created": "Thu, 29 Jun 2006 15:25:42 GMT", "version": "v1" }, { "created": "Tue, 29 Aug 2006 15:59:17 GMT", "version": "v2" } ]
2008-11-26
[ [ "Agashe", "Kaustubh", "" ], [ "Perez", "Gilad", "" ], [ "Soni", "Amarjit", "" ] ]
We study top quark flavor violation in the framework of a warped extra dimension with the Standard Model (SM) fields propagating in the bulk. Such a scenario provides solutions to both the Planck-weak hierarchy problem and the flavor puzzle of the SM without inducing a flavor problem. We find that, generically, tcZ couplings receive a huge enhancement, in particular the right handed ones can be O(1%). This results in BR(t -> c Z) at or above the sensitivity of the Large Hadron Collider (LHC). At the International Linear Collider (ILC), single top production, via e^+ e^- -> t \bar c, can be a striking signal for this scenario. In particular, it represents a physics topic of critical importance that can be explored even with a relatively low energy option, close to the tc threshold. At both the LHC and the ILC, angular distributions can probe the above prediction of dominance of right-handed couplings.
hep-ph/0602030
Scott A. Yost
Scott A. Yost and B.F.L. Ward
Virtual Corrections to Bremsstrahlung in High-Energy Collider Physics: LHC and e+ e- Colliders
Presented at RADCOR 2005: Application of Quantum Field Theory to Phenomenology, Shonan Village, Japan, Oct. 2-7, 2005 (5 pages, 6 EPS figures, uses espcrc2.sty)
null
10.1016/j.nuclphysbps.2006.03.038
BU-HEPP-06/03
hep-ph
null
We describe radiative corrections to bremsstrahlung and their application to high energy collider physics, focusing on the applications to luminosity measurement, fermion pair production and radiative return. We review the status of one loop radiative corrections in BHLUMI and the KKMC, including cross checks with newer results developed independently for radiative return. We outline a YFS-exponentiated approach to the Drell-Yan process for LHC physics, including a discussion of the relevant radiative corrections.
[ { "created": "Thu, 2 Feb 2006 23:26:38 GMT", "version": "v1" } ]
2009-11-11
[ [ "Yost", "Scott A.", "" ], [ "Ward", "B. F. L.", "" ] ]
We describe radiative corrections to bremsstrahlung and their application to high energy collider physics, focusing on the applications to luminosity measurement, fermion pair production and radiative return. We review the status of one loop radiative corrections in BHLUMI and the KKMC, including cross checks with newer results developed independently for radiative return. We outline a YFS-exponentiated approach to the Drell-Yan process for LHC physics, including a discussion of the relevant radiative corrections.
1910.04090
Antonio Pineda
Cesar Ayala, Xabier Lobregat, Antonio Pineda
Hyperasymptotic approximation to the operator product expansion
9 pages, 7 figures, Proceedings for the 22th International Conference in Quantum Chromodynamics (QCD 19), 2-5 July 2019, Montpellier, France
null
null
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
These proceedings review recent work on hyperasymptotic constructions to the operator product expansion. Quantities we consider are the static potential and the pole mass.
[ { "created": "Wed, 9 Oct 2019 16:08:27 GMT", "version": "v1" } ]
2019-10-11
[ [ "Ayala", "Cesar", "" ], [ "Lobregat", "Xabier", "" ], [ "Pineda", "Antonio", "" ] ]
These proceedings review recent work on hyperasymptotic constructions to the operator product expansion. Quantities we consider are the static potential and the pole mass.
1603.00718
Dario Buttazzo
Riccardo Barbieri, Dario Buttazzo, Lawrence J. Hall, David Marzocca
Higgs mass and unified gauge coupling in the NMSSM with Vector Matter
15 pages, 8 figures, 1 table. v2: clarifications added in sections 2 and 3, figures updated, matches published version
JHEP 1607 (2016) 067
10.1007/JHEP07(2016)067
ZU-TH-8/16
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider the NMSSM extended to include one vector-like family of quarks and leptons. If (some of) these vector-like matter particles, as the Higgs doublets, have Yukawa couplings to the singlet S that exceed unity at about the same scale $\Lambda \lesssim 10^3$ TeV, this gives the order 40 % enhancement of the tree level Higgs boson mass required in the MSSM to reach 125 GeV. It is conceivable that the Yukawa couplings to the singlet S, although naively blowing up close to $\Lambda$, will not spoil gauge coupling unification. In such a case the unified coupling $\alpha_X$ could be interestingly led to a value not far from unity, thus providing a possible explanation for the number of generations. The characteristic signal is an enhanced resonant production of neutral spin zero particles at LHC, that could even explain the putative diphoton resonance hinted by the recent LHC data at 750 GeV.
[ { "created": "Wed, 2 Mar 2016 14:16:08 GMT", "version": "v1" }, { "created": "Tue, 19 Jul 2016 10:41:26 GMT", "version": "v2" } ]
2016-07-20
[ [ "Barbieri", "Riccardo", "" ], [ "Buttazzo", "Dario", "" ], [ "Hall", "Lawrence J.", "" ], [ "Marzocca", "David", "" ] ]
We consider the NMSSM extended to include one vector-like family of quarks and leptons. If (some of) these vector-like matter particles, as the Higgs doublets, have Yukawa couplings to the singlet S that exceed unity at about the same scale $\Lambda \lesssim 10^3$ TeV, this gives the order 40 % enhancement of the tree level Higgs boson mass required in the MSSM to reach 125 GeV. It is conceivable that the Yukawa couplings to the singlet S, although naively blowing up close to $\Lambda$, will not spoil gauge coupling unification. In such a case the unified coupling $\alpha_X$ could be interestingly led to a value not far from unity, thus providing a possible explanation for the number of generations. The characteristic signal is an enhanced resonant production of neutral spin zero particles at LHC, that could even explain the putative diphoton resonance hinted by the recent LHC data at 750 GeV.
1603.05213
Antonio Ortiz
Antonio Ortiz, Gyula Benc\'edi, H\'ector Bello and Satyajit Jena
Jet effects in high-multiplicity pp events
5 pages, 2 figures. Proceedings of the 7th International Workshop on Multiple Partonic Interactions at the LHC, Trieste, Italy
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The study of the high-multiplicity pp events has become important because we need to understand the origin of the fluid-like features which have been found in such small systems. In this work we concentrate on the radial flow signatures. To this end, the role of jets in high-multiplicity pp collisions is investigated using PYTHIA 8.
[ { "created": "Wed, 16 Mar 2016 18:39:02 GMT", "version": "v1" } ]
2016-03-17
[ [ "Ortiz", "Antonio", "" ], [ "Bencédi", "Gyula", "" ], [ "Bello", "Héctor", "" ], [ "Jena", "Satyajit", "" ] ]
The study of the high-multiplicity pp events has become important because we need to understand the origin of the fluid-like features which have been found in such small systems. In this work we concentrate on the radial flow signatures. To this end, the role of jets in high-multiplicity pp collisions is investigated using PYTHIA 8.
hep-ph/0202101
D. R. T. Jones
I. Jack, D.R.T. Jones and R. Wild
Fayet-Iliopoulos D-terms, neutrino masses and anomaly mediated supersymmetry breaking
13 pages, TeX, Uses Harvmac (big). Improved R-parity discussion (v2). Redundant singlet excised (v3). Figure added and minor corrections, added references (v4)
Phys.Lett. B535 (2002) 193-200
10.1016/S0370-2693(02)01775-6
LTH 533
hep-ph
null
We explore, in the context of the MSSM generalised to admit massive neutrinos, an extension of the Anomaly Mediated Supersymmetry Breaking solution for the soft scalar masses to incorporate Fayet-Iliopoulos D-terms. The slepton mass problem characteristic of the scenario is resolved, and the fermion mass hierarchy is explained via the Froggatt-Nielsen mechanism. FCNC problems are evaded by a combination of universal doublet charges and Yukawa textures which are diagonalised by transforming the left-handed fields only.
[ { "created": "Mon, 11 Feb 2002 17:53:41 GMT", "version": "v1" }, { "created": "Thu, 14 Feb 2002 19:45:03 GMT", "version": "v2" }, { "created": "Tue, 19 Feb 2002 18:06:55 GMT", "version": "v3" }, { "created": "Fri, 6 Sep 2002 14:18:32 GMT", "version": "v4" } ]
2009-11-07
[ [ "Jack", "I.", "" ], [ "Jones", "D. R. T.", "" ], [ "Wild", "R.", "" ] ]
We explore, in the context of the MSSM generalised to admit massive neutrinos, an extension of the Anomaly Mediated Supersymmetry Breaking solution for the soft scalar masses to incorporate Fayet-Iliopoulos D-terms. The slepton mass problem characteristic of the scenario is resolved, and the fermion mass hierarchy is explained via the Froggatt-Nielsen mechanism. FCNC problems are evaded by a combination of universal doublet charges and Yukawa textures which are diagonalised by transforming the left-handed fields only.
hep-ph/0108222
Einan Gardi
Einan Gardi (CERN)
Dressed gluon exponentiation
28 pages
Nucl.Phys. B622 (2002) 365-392
10.1016/S0550-3213(01)00594-6
CERN-TH/2001-229
hep-ph
null
Perturbative and non-perturbative aspects of differential cross-sections close to a kinematic threshold are studied applying ``dressed gluon exponentiation'' (DGE). The factorization property of soft and collinear gluon radiation is demonstrated using the light-cone axial gauge: it is shown that the singular part of the squared matrix element for the emission of an off-shell gluon off a nearly on-shell quark is universal. We derive a generalized splitting function that describes the emission probability and show how Sudakov logs emerge from the phase-space boundary where the gluon transverse momentum vanishes. Both soft and collinear logs associated with a single dressed gluon are computed through a single integral over the running-coupling to any logarithmic accuracy. The result then serves as the kernel for exponentiation. The divergence of the perturbative series in the exponent indicates specific non-perturbative corrections. We identify two classes of observables according to whether the radiation is from an initial-state quark, as in the Drell-Yan process, or a final-state quark, forming a jet with a constrained invariant mass, as in fragmentation functions, event-shape variables and deep inelastic structure functions.
[ { "created": "Mon, 27 Aug 2001 13:51:29 GMT", "version": "v1" } ]
2009-11-07
[ [ "Gardi", "Einan", "", "CERN" ] ]
Perturbative and non-perturbative aspects of differential cross-sections close to a kinematic threshold are studied applying ``dressed gluon exponentiation'' (DGE). The factorization property of soft and collinear gluon radiation is demonstrated using the light-cone axial gauge: it is shown that the singular part of the squared matrix element for the emission of an off-shell gluon off a nearly on-shell quark is universal. We derive a generalized splitting function that describes the emission probability and show how Sudakov logs emerge from the phase-space boundary where the gluon transverse momentum vanishes. Both soft and collinear logs associated with a single dressed gluon are computed through a single integral over the running-coupling to any logarithmic accuracy. The result then serves as the kernel for exponentiation. The divergence of the perturbative series in the exponent indicates specific non-perturbative corrections. We identify two classes of observables according to whether the radiation is from an initial-state quark, as in the Drell-Yan process, or a final-state quark, forming a jet with a constrained invariant mass, as in fragmentation functions, event-shape variables and deep inelastic structure functions.
2209.06881
Daniel Salinas-Arizmendi
Daniel Salinas-Arizmendi and Iv\'an Schmidt
Relation between pole and running masses of heavy quarks using the principle of maximum conformality
13 pages, 8 figures
null
10.1093/ptep/ptae020
null
hep-ph
http://creativecommons.org/licenses/by-sa/4.0/
The relation of the pole and running heavy quark masses of order $\mathcal{O}\left(\alpha_s^4\right)$ in perturbative quantum chromodynamics (pQCD) can be obtained using the Principle of Maximum Conformality (PMC), a formalism that provides a rigorous method for eliminating renormalization scale and scheme ambiguities for observables in pQCD. Using PMC, an optimal renormalization scale for the heavy quark mass ratio is determined, independent of the renormalization scale and scheme up to order $\alpha_s^4$. Precise values are then obtained for the PMC pole masses of the heavy quarks $M_b^{\text{PMC}}=4.86^{+0.03}_{-0.02}$ GeV, $M_t^{\text{PMC}}=172.3\pm 0.6$ GeV, and the running mass $\overline{m}_t^{\text{PMC}}=162.6\pm 0.7$ GeV at the PMC scale.
[ { "created": "Wed, 14 Sep 2022 18:55:13 GMT", "version": "v1" }, { "created": "Thu, 7 Dec 2023 23:32:41 GMT", "version": "v2" }, { "created": "Tue, 13 Feb 2024 13:43:31 GMT", "version": "v3" } ]
2024-02-14
[ [ "Salinas-Arizmendi", "Daniel", "" ], [ "Schmidt", "Iván", "" ] ]
The relation of the pole and running heavy quark masses of order $\mathcal{O}\left(\alpha_s^4\right)$ in perturbative quantum chromodynamics (pQCD) can be obtained using the Principle of Maximum Conformality (PMC), a formalism that provides a rigorous method for eliminating renormalization scale and scheme ambiguities for observables in pQCD. Using PMC, an optimal renormalization scale for the heavy quark mass ratio is determined, independent of the renormalization scale and scheme up to order $\alpha_s^4$. Precise values are then obtained for the PMC pole masses of the heavy quarks $M_b^{\text{PMC}}=4.86^{+0.03}_{-0.02}$ GeV, $M_t^{\text{PMC}}=172.3\pm 0.6$ GeV, and the running mass $\overline{m}_t^{\text{PMC}}=162.6\pm 0.7$ GeV at the PMC scale.
2312.12523
Sumit Kumar Garg
Mariana Frank, Benjamin Fuks, Sumit K. Garg, Poulose Poulose
Flavour-changing top quark decays in the alternative left-right model
8 pages, 2 figures; v2: some clarifications and references added, Matches the published version
Phys.Lett.B 850 (2024)138548
10.1016/j.physletb.2024.138548
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We examine flavour-changing neutral-current decays of the top quark, $t\to q \gamma$, $t \to qZ$, $t \to q H$, and $ t\to q g$ (with $q=u, c$), in the Alternative Left-Right Model, a left right-symmetric model featuring exotic quarks and light bosons. These decays have a very small probability of occurring within the Standard Model, but they can be enhanced in this model through the presence of the exotic states. While associated signals may be detected directly at the LHC, rare decays have the advantage of offering means to probe new particles indirectly, through loop-contributions. We perform a comprehensive analysis of the model's parameter space to demonstrate the possible existence of enhancements in the corresponding branching ratios, of $10^6$ for the branching ratios $\mathcal{B}(t\to uZ)$ and $\mathcal{B}(t \to uH)$, and in the range of $10^{2} - 10^{4}$ for the other decays, relative to the Standard Model. We subsequently determine the preferred parameter space regions of the model in terms of potential of being reached in the near future.
[ { "created": "Tue, 19 Dec 2023 19:00:09 GMT", "version": "v1" }, { "created": "Fri, 1 Mar 2024 07:30:07 GMT", "version": "v2" } ]
2024-03-04
[ [ "Frank", "Mariana", "" ], [ "Fuks", "Benjamin", "" ], [ "Garg", "Sumit K.", "" ], [ "Poulose", "Poulose", "" ] ]
We examine flavour-changing neutral-current decays of the top quark, $t\to q \gamma$, $t \to qZ$, $t \to q H$, and $ t\to q g$ (with $q=u, c$), in the Alternative Left-Right Model, a left right-symmetric model featuring exotic quarks and light bosons. These decays have a very small probability of occurring within the Standard Model, but they can be enhanced in this model through the presence of the exotic states. While associated signals may be detected directly at the LHC, rare decays have the advantage of offering means to probe new particles indirectly, through loop-contributions. We perform a comprehensive analysis of the model's parameter space to demonstrate the possible existence of enhancements in the corresponding branching ratios, of $10^6$ for the branching ratios $\mathcal{B}(t\to uZ)$ and $\mathcal{B}(t \to uH)$, and in the range of $10^{2} - 10^{4}$ for the other decays, relative to the Standard Model. We subsequently determine the preferred parameter space regions of the model in terms of potential of being reached in the near future.
hep-ph/0206167
Heather E. Logan
Marcela Carena, Debajyoti Choudhury, Rodolfo A. Diaz, Heather E. Logan, and Carlos E.M. Wagner
Top-squark searches at the Tevatron in models of low-energy supersymmetry breaking
32 pages, 9 figures; references added
Phys.Rev.D66:115010,2002
10.1103/PhysRevD.66.115010
ANL-HEP-PR-02-042, EFI-02-88, FERMILAB-Pub-02-072-T
hep-ph
null
We study the production and decays of top squarks (stops) at the Tevatron collider in models of low-energy supersymmetry breaking. We consider the case where the lightest Standard Model (SM) superpartner is a light neutralino that predominantly decays into a photon and a light gravitino. Considering the lighter stop to be the next-to-lightest Standard Model superpartner, we analyze stop signatures associated with jets, photons and missing energy, which lead to signals naturally larger than the associated SM backgrounds. We consider both 2-body and 3-body decays of the top squarks and show that the reach of the Tevatron can be significantly larger than that expected within either the standard supergravity models or models of low-energy supersymmetry breaking in which the stop is the lightest SM superpartner. For a modest projection of the final Tevatron luminosity, L = 4 fb-1, stop masses of order 300 GeV are accessible at the Tevatron collider in both 2-body and 3-body decay modes. We also consider the production and decay of ten degenerate squarks that are the supersymmetric partners of the five light quarks. In this case we find that common squark masses up to 360 GeV are easily accessible at the Tevatron collider, and that the reach increases further if the gluino is light.
[ { "created": "Tue, 18 Jun 2002 21:20:05 GMT", "version": "v1" }, { "created": "Tue, 2 Jul 2002 18:28:48 GMT", "version": "v2" } ]
2008-11-26
[ [ "Carena", "Marcela", "" ], [ "Choudhury", "Debajyoti", "" ], [ "Diaz", "Rodolfo A.", "" ], [ "Logan", "Heather E.", "" ], [ "Wagner", "Carlos E. M.", "" ] ]
We study the production and decays of top squarks (stops) at the Tevatron collider in models of low-energy supersymmetry breaking. We consider the case where the lightest Standard Model (SM) superpartner is a light neutralino that predominantly decays into a photon and a light gravitino. Considering the lighter stop to be the next-to-lightest Standard Model superpartner, we analyze stop signatures associated with jets, photons and missing energy, which lead to signals naturally larger than the associated SM backgrounds. We consider both 2-body and 3-body decays of the top squarks and show that the reach of the Tevatron can be significantly larger than that expected within either the standard supergravity models or models of low-energy supersymmetry breaking in which the stop is the lightest SM superpartner. For a modest projection of the final Tevatron luminosity, L = 4 fb-1, stop masses of order 300 GeV are accessible at the Tevatron collider in both 2-body and 3-body decay modes. We also consider the production and decay of ten degenerate squarks that are the supersymmetric partners of the five light quarks. In this case we find that common squark masses up to 360 GeV are easily accessible at the Tevatron collider, and that the reach increases further if the gluino is light.
1905.09144
Ian Balitsky
Ian Balitsky and Giovanni A. Chirilli
Conformal invariance of TMD rapidity evolution
5 pages, 1 figure
Phys. Rev. D 100, 051504 (2019)
10.1103/PhysRevD.100.051504
JLAB-THY-19-2940
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We discuss conformal properties of TMD operators and present the result of the conformal rapidity evolution of TMD operators in the Sudakov region.
[ { "created": "Wed, 22 May 2019 13:56:38 GMT", "version": "v1" } ]
2019-09-25
[ [ "Balitsky", "Ian", "" ], [ "Chirilli", "Giovanni A.", "" ] ]
We discuss conformal properties of TMD operators and present the result of the conformal rapidity evolution of TMD operators in the Sudakov region.
hep-ph/0101232
V. A. Ilyin
A.S.Belyaev, E.E.Boos, A.N.Vologdin, M.N.Dubinin, V.A.Ilyin, A.P.Kryukov, A.E.Pukhov, A.N.Skachkova, V.I.Savrin, A.V.Sherstnev, S.A.Shichanin
CompHEP-PYTHIA interface: integrated package for the collision events generation based on exact matrix elements
Standard LaTeX, 4 pages. To appear in the proceedings of the Seventh International Workshop on Advanced Computing and Analysis Technics in Physics Research (ACAT2000, Fermilab, October 16-20, 2000)
null
10.1063/1.1405306
null
hep-ph
null
CompHEP, as a partonic event generator, and PYTHIA, as a generator of final states of detectable objects, are interfaced. Thus, integrated tool is proposed for simulation of (almost) arbitrary collision processes at the level of detectable particles. Exact (multiparticle) matrix elements, convolution with structure functions, decays, partons hadronization and (optionally) parton shower evolution are basic stages of calculations. The PEVLIB library of event generators for LHC processes is described.
[ { "created": "Sun, 21 Jan 2001 19:46:40 GMT", "version": "v1" } ]
2009-11-07
[ [ "Belyaev", "A. S.", "" ], [ "Boos", "E. E.", "" ], [ "Vologdin", "A. N.", "" ], [ "Dubinin", "M. N.", "" ], [ "Ilyin", "V. A.", "" ], [ "Kryukov", "A. P.", "" ], [ "Pukhov", "A. E.", "" ], [ "Skachk...
CompHEP, as a partonic event generator, and PYTHIA, as a generator of final states of detectable objects, are interfaced. Thus, integrated tool is proposed for simulation of (almost) arbitrary collision processes at the level of detectable particles. Exact (multiparticle) matrix elements, convolution with structure functions, decays, partons hadronization and (optionally) parton shower evolution are basic stages of calculations. The PEVLIB library of event generators for LHC processes is described.
hep-ph/9904343
A. F. W. van Hameren
A. van Hameren and R. Kleiss
Scaling limits for the Lego discrepancy
16 pages
Nucl.Phys. B558 (1999) 621-636
10.1016/S0550-3213(99)00411-3
null
hep-ph physics.data-an
null
For the Lego discrepancy with M bins, which is equivalent with a chi^2-statistic with M bins, we present a procedure to calculate the moment generating function of the probability distribution perturbatively if M and N, the number of uniformly and randomly distributed data points, become large. Furthermore, we present a phase diagram for various limits of the probability distribution in terms of the standardized variable if M and N become infinite.
[ { "created": "Thu, 15 Apr 1999 09:42:45 GMT", "version": "v1" } ]
2009-10-31
[ [ "van Hameren", "A.", "" ], [ "Kleiss", "R.", "" ] ]
For the Lego discrepancy with M bins, which is equivalent with a chi^2-statistic with M bins, we present a procedure to calculate the moment generating function of the probability distribution perturbatively if M and N, the number of uniformly and randomly distributed data points, become large. Furthermore, we present a phase diagram for various limits of the probability distribution in terms of the standardized variable if M and N become infinite.
hep-ph/0211460
Frieder Kleefeld
F. Kleefeld (CFIF, IST, Lisbon, Portugal)
Consistent relativistic Quantum Theory for systems/particles described by non-Hermitian Hamiltonians and Lagrangians
14 pages, no figures; invited contribution to the 2nd Int. Workshop on "Hadron Physics, Effective Theories of Low Energy QCD", CFT, Coimbra University, Portugal, September 25-29, 2002; ref. 15 updated
AIP Conf.Proc.660:325-338,2003
10.1063/1.1570583
FK-2002-4
hep-ph
null
A causal, non-Hermitian, renormalizable, local, unitary and Lorentz convariant formulation of Quantum Theory (QT) (= Quantum Mechanics (QM) and Quantum Field Theory (QFT)) is developed which is free of formalistic problems we face in the commonly used Hermitian formulation of QT. Side effects of the new formulation of QT are the derivation of a consistent (anti)causal neutrino Lagrangian, the enrichment of chiral symmetries, the removal of the Dirac sea, the separation of positive and negative energy states including a reformulation of the anti-particle concept and a critical analysis of the concept of probability currents. In a first step we apply the new formulation of QT to establish a relation between perturbative Quantum Chromodynamics (QCD) and the (axial)vector meson extended Quark-Level Linear Sigma Model (QLLSM) at high energies.
[ { "created": "Fri, 29 Nov 2002 15:17:23 GMT", "version": "v1" }, { "created": "Mon, 2 Dec 2002 16:39:57 GMT", "version": "v2" }, { "created": "Thu, 5 Dec 2002 15:22:32 GMT", "version": "v3" }, { "created": "Thu, 6 Feb 2003 23:12:14 GMT", "version": "v4" } ]
2011-07-19
[ [ "Kleefeld", "F.", "", "CFIF, IST, Lisbon, Portugal" ] ]
A causal, non-Hermitian, renormalizable, local, unitary and Lorentz convariant formulation of Quantum Theory (QT) (= Quantum Mechanics (QM) and Quantum Field Theory (QFT)) is developed which is free of formalistic problems we face in the commonly used Hermitian formulation of QT. Side effects of the new formulation of QT are the derivation of a consistent (anti)causal neutrino Lagrangian, the enrichment of chiral symmetries, the removal of the Dirac sea, the separation of positive and negative energy states including a reformulation of the anti-particle concept and a critical analysis of the concept of probability currents. In a first step we apply the new formulation of QT to establish a relation between perturbative Quantum Chromodynamics (QCD) and the (axial)vector meson extended Quark-Level Linear Sigma Model (QLLSM) at high energies.
1507.02868
Tommy Ohlsson
Mattias Blennow, Sandhya Choubey, Tommy Ohlsson, Sushant K. Raut
Exploring Source and Detector Non-Standard Neutrino Interactions at ESS$\nu$SB
26 pages, 10 figures. Final version published in JHEP
JHEP 09 (2015) 096
10.1007/JHEP09(2015)096
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate source and detector non-standard neutrino interactions at the proposed ESS$\nu$SB experiment. We analyze the effect of non-standard physics at the probability level, the event-rate level and by a full computation of the ESS$\nu$SB setup. We find that the precision measurement of the leptonic mixing angle $\theta_{23}$ at ESS$\nu$SB is robust in the presence of non-standard interactions, whereas that of the leptonic CP-violating phase $\delta$ is worsened at most by a factor of two. We compute sensitivities to all the relevant source and decector non-standard interaction parameters and find that the sensitivities to the parameters $\varepsilon^s_{\mu e}$ and $\varepsilon^d_{\mu e}$ are comparable to the existing limits in a realistic scenario, while they improve by a factor of two in an optimistic scenario. Finally, we show that the absence of a near detector compromises the sensitivity of ESS$\nu$SB to non-standard interactions.
[ { "created": "Fri, 10 Jul 2015 12:21:44 GMT", "version": "v1" }, { "created": "Sun, 27 Sep 2015 09:06:18 GMT", "version": "v2" } ]
2015-09-29
[ [ "Blennow", "Mattias", "" ], [ "Choubey", "Sandhya", "" ], [ "Ohlsson", "Tommy", "" ], [ "Raut", "Sushant K.", "" ] ]
We investigate source and detector non-standard neutrino interactions at the proposed ESS$\nu$SB experiment. We analyze the effect of non-standard physics at the probability level, the event-rate level and by a full computation of the ESS$\nu$SB setup. We find that the precision measurement of the leptonic mixing angle $\theta_{23}$ at ESS$\nu$SB is robust in the presence of non-standard interactions, whereas that of the leptonic CP-violating phase $\delta$ is worsened at most by a factor of two. We compute sensitivities to all the relevant source and decector non-standard interaction parameters and find that the sensitivities to the parameters $\varepsilon^s_{\mu e}$ and $\varepsilon^d_{\mu e}$ are comparable to the existing limits in a realistic scenario, while they improve by a factor of two in an optimistic scenario. Finally, we show that the absence of a near detector compromises the sensitivity of ESS$\nu$SB to non-standard interactions.
1504.07001
Pere Masjuan
Pere Masjuan, Pablo Sanchez-Puertas
Phenomenology of bivariate approximants: the pi0 to e+e- case and its impact on the electron and muon g-2
v2: 7 pages, 5 figures. Improved approximation, reduced final errors, conclusions unchanged
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The current 3$\sigma$ discrepancy between experiment and Standard Model predictions for $\pi^0 \to e^+e^-$ is reconsidered using the Pad\'e Theory for bivariate functions, the Canterbury approximants. This method provides a model-independent data-driven approximation to the decay as soon as experimental data for the doubly virtual $\pi^0$ transition form factor are available. It also implements the correct QCD constraints of the form factor both at low- and high-energies. We reassess the Standard Model result including, for the first time, a systematic error. Our result, BR$(\pi^0 \to e^+e^-)=6.23(5)\times 10^{-8}$, still represents a discrepancy larger than $2\sigma$, unsurmountable with our present knowledge of the Standard Model, and would claim New Physics if the experimental result is confirmed by a new measurement. Our method also provides the adequate tool to extract the doubly virtual form factor from experimental data in a straightforward manner. This measurement would further shrink our error and establish once and for all the New Physics nature of the discrepancy. In addition, we remark the challenge this discrepancy poses in the evaluation of the hadronic light-by-light scattering contribution to the $(g-2)_{\mu}$, specially confronted with the foreseen accuracy of the forthcoming $(g-2)_{\mu}$ experiments.
[ { "created": "Mon, 27 Apr 2015 09:43:30 GMT", "version": "v1" }, { "created": "Mon, 21 Mar 2016 13:32:01 GMT", "version": "v2" } ]
2016-03-22
[ [ "Masjuan", "Pere", "" ], [ "Sanchez-Puertas", "Pablo", "" ] ]
The current 3$\sigma$ discrepancy between experiment and Standard Model predictions for $\pi^0 \to e^+e^-$ is reconsidered using the Pad\'e Theory for bivariate functions, the Canterbury approximants. This method provides a model-independent data-driven approximation to the decay as soon as experimental data for the doubly virtual $\pi^0$ transition form factor are available. It also implements the correct QCD constraints of the form factor both at low- and high-energies. We reassess the Standard Model result including, for the first time, a systematic error. Our result, BR$(\pi^0 \to e^+e^-)=6.23(5)\times 10^{-8}$, still represents a discrepancy larger than $2\sigma$, unsurmountable with our present knowledge of the Standard Model, and would claim New Physics if the experimental result is confirmed by a new measurement. Our method also provides the adequate tool to extract the doubly virtual form factor from experimental data in a straightforward manner. This measurement would further shrink our error and establish once and for all the New Physics nature of the discrepancy. In addition, we remark the challenge this discrepancy poses in the evaluation of the hadronic light-by-light scattering contribution to the $(g-2)_{\mu}$, specially confronted with the foreseen accuracy of the forthcoming $(g-2)_{\mu}$ experiments.
1709.09920
C. Hanhart
C. Hanhart
Theory of hadronic molecules applied to the XYZ states
6 pages, 3 figures. Invited talk presented at the phi to psi conference, 2017, Mainz, Germany
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In recent years data have been accumulated at various experiments about states in the heavy quarkonium mass range that seem to be inconsistent with the most simple variants of the quark model. In this contribution it is demonstrated that most of those data are consistent with a dominant molecular nature of those states. It is also discussed which kind of observables are sensitive to the molecular component and which are not.
[ { "created": "Thu, 28 Sep 2017 12:37:28 GMT", "version": "v1" } ]
2017-09-29
[ [ "Hanhart", "C.", "" ] ]
In recent years data have been accumulated at various experiments about states in the heavy quarkonium mass range that seem to be inconsistent with the most simple variants of the quark model. In this contribution it is demonstrated that most of those data are consistent with a dominant molecular nature of those states. It is also discussed which kind of observables are sensitive to the molecular component and which are not.
hep-ph/0105298
J. J. G\'omez Cadenas
J.J.Gomez-Cadenas (Valencia University & CERN)
Measurement of CP violation at a Neutrino Factory
Invited talk given at the CP2000 Conference in Ferrara, September, 2000
Nucl.Phys.Proc.Suppl.99B:304-311,2001
10.1016/S0920-5632(01)01390-1
IFIC/01-32
hep-ph
null
The prospects of measuring CP violation in the leptonic sector using the intense neutrino beams arising from muon decay in the straight sections of a muon accumulator ring (the so-called neutrino factory) are discussed.
[ { "created": "Tue, 29 May 2001 08:20:53 GMT", "version": "v1" } ]
2014-11-17
[ [ "Gomez-Cadenas", "J. J.", "", "Valencia University & CERN" ] ]
The prospects of measuring CP violation in the leptonic sector using the intense neutrino beams arising from muon decay in the straight sections of a muon accumulator ring (the so-called neutrino factory) are discussed.
1502.06891
Marco Drewes
Marco Drewes
Theoretical Status of Neutrino Physics
21 pages, 17 figures, 1 table. This mini-review is based on my talk at the 16th International Workshop on Neutrino Factories and Future Neutrino Beam Facilities (NUFACT2014)
PoS(NUFACT2014)001
null
TUM-HEP-981/15
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In the framework of renormalisable relativistic quantum field theory, the explanation of neutrino masses necessarily requires the existence of new physical states. These new states may also be responsible for other unexplained phenomena in particle physics and cosmology. After a brief introduction, I focus on scenarios in which the neutrino masses are generated by the type-I seesaw mechanism and review the phenomenological implications of different choices of the seesaw scale.
[ { "created": "Tue, 24 Feb 2015 17:45:46 GMT", "version": "v1" } ]
2015-07-31
[ [ "Drewes", "Marco", "" ] ]
In the framework of renormalisable relativistic quantum field theory, the explanation of neutrino masses necessarily requires the existence of new physical states. These new states may also be responsible for other unexplained phenomena in particle physics and cosmology. After a brief introduction, I focus on scenarios in which the neutrino masses are generated by the type-I seesaw mechanism and review the phenomenological implications of different choices of the seesaw scale.
1105.2653
Kang Young Lee
Yeong Gyun Kim, Kang Young Lee
Early LHC bound on W' boson in the nonuniversal gauge interaction model
6 pages, 3 figures
Phys. Lett. B 706 (2012) 367
10.1016/j.physletb.2011.11.032
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the phenomenology of the heavy charged gauge boson and obtain the lower bounds on its mass with the early LHC data at 7 TeV center-of-mass energy in the nonuniversal gauge interaction model, in which the electroweak SU(2) gauge group depends upon the fermion family. We found that the direct bound on the mass of the $W'$ boson is compatible to the indirect bound with only the early data of the LHC.
[ { "created": "Fri, 13 May 2011 08:33:32 GMT", "version": "v1" } ]
2012-03-13
[ [ "Kim", "Yeong Gyun", "" ], [ "Lee", "Kang Young", "" ] ]
We study the phenomenology of the heavy charged gauge boson and obtain the lower bounds on its mass with the early LHC data at 7 TeV center-of-mass energy in the nonuniversal gauge interaction model, in which the electroweak SU(2) gauge group depends upon the fermion family. We found that the direct bound on the mass of the $W'$ boson is compatible to the indirect bound with only the early data of the LHC.
hep-ph/9610275
U. Meissner
G. M\"uller, Ulf-G. Mei{\ss}ner
Renormalization of the three flavor Lagrangian in heavy baryon chiral perturbation theory
40 pp, LaTeX, 3 figs, uses epsf, slight changes in some equations and phrasing, table 1 in more compact form, accepted for publication in Nucl. Phys. B
Nucl.Phys. B492 (1997) 379-416
10.1016/S0550-3213(97)80039-9
TK 96 24 and KFA-IKP(TH)-1996-07
hep-ph nucl-th
null
The complete renormalization of the generating functional for Green functions of quark currents between one--baryon states in three flavor heavy baryon chiral perturbation theory is performed to order q^3. As an example, we study the kaon loop induced divergences in neutral pion photoproduction off protons.
[ { "created": "Mon, 7 Oct 1996 20:33:04 GMT", "version": "v1" }, { "created": "Thu, 16 Jan 1997 07:08:07 GMT", "version": "v2" } ]
2015-06-25
[ [ "Müller", "G.", "" ], [ "Meißner", "Ulf-G.", "" ] ]
The complete renormalization of the generating functional for Green functions of quark currents between one--baryon states in three flavor heavy baryon chiral perturbation theory is performed to order q^3. As an example, we study the kaon loop induced divergences in neutral pion photoproduction off protons.
2012.02926
Kazuki Ikeda
Kazuki Ikeda, Dmitri E. Kharzeev, Yuta Kikuchi
Real-time dynamics of Chern-Simons fluctuations near a critical point
9 pages, 5 figures
Phys. Rev. D 103, 071502 (2021)
10.1103/PhysRevD.103.L071502
null
hep-ph hep-lat nucl-th quant-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The real-time topological susceptibility is studied in $(1+1)$-dimensional massive Schwinger model with a $\theta$-term. We evaluate the real-time correlation function of electric field that represents the topological Chern-Pontryagin number density in $(1+1)$ dimensions. Near the parity-breaking critical point located at $\theta=\pi$ and fermion mass $m$ to coupling $g$ ratio of $m/g \approx 0.33$, we observe a sharp maximum in the topological susceptibility. We interpret this maximum in terms of the growth of critical fluctuations near the critical point, and draw analogies between the massive Schwinger model, QCD near the critical point, and ferroelectrics near the Curie point.
[ { "created": "Sat, 5 Dec 2020 02:27:02 GMT", "version": "v1" }, { "created": "Fri, 26 Feb 2021 17:05:48 GMT", "version": "v2" } ]
2021-04-28
[ [ "Ikeda", "Kazuki", "" ], [ "Kharzeev", "Dmitri E.", "" ], [ "Kikuchi", "Yuta", "" ] ]
The real-time topological susceptibility is studied in $(1+1)$-dimensional massive Schwinger model with a $\theta$-term. We evaluate the real-time correlation function of electric field that represents the topological Chern-Pontryagin number density in $(1+1)$ dimensions. Near the parity-breaking critical point located at $\theta=\pi$ and fermion mass $m$ to coupling $g$ ratio of $m/g \approx 0.33$, we observe a sharp maximum in the topological susceptibility. We interpret this maximum in terms of the growth of critical fluctuations near the critical point, and draw analogies between the massive Schwinger model, QCD near the critical point, and ferroelectrics near the Curie point.
1411.6695
Jing Shu
Ligong Bian, Tao Liu, Jing Shu
Post-ACME2013 CP-violation in Higgs Physics and Electroweak Baryogenesis
9 pages, 4 figures, 2 tables
Phys. Rev. Lett. 115, 021801 (2015)
10.1103/PhysRevLett.115.021801
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a class of cancellation mechanisms to suppress the total contributions of Barr-Zee diagrams to the electron electric dipole moment (eEDM). This class of mechanisms are of particular significance after the new eEDM upper limit, which strongly constrains the allowed magnitude of CP-violation in Higgs couplings and hence the feasibility of electroweak baryogenesis (EWBG), were released by the ACME collaboration in 2013. We point out: if both the CP-odd Higgs-photon-photon ($Z$ boson) and the CP-odd Higgs-electron-positron couplings are turned on, a cancellation may occur either between the contributions of a CP-mixing Higgs boson, with the other Higgs bosons being decoupled, or between the contributions of a CP-even and a CP-odd Higgs bosons. With the assistance of the cancellation mechanisms, a large CP-phase in Higgs couplings with viable electroweak baryogenesis (EWBG) is still allowed. The reopened parameter regions would be probed by the future neutron, mercury EDM measurements, and direct measurements of Higgs CP-properties at the LHC and future colliders.
[ { "created": "Tue, 25 Nov 2014 00:35:00 GMT", "version": "v1" } ]
2015-07-15
[ [ "Bian", "Ligong", "" ], [ "Liu", "Tao", "" ], [ "Shu", "Jing", "" ] ]
We present a class of cancellation mechanisms to suppress the total contributions of Barr-Zee diagrams to the electron electric dipole moment (eEDM). This class of mechanisms are of particular significance after the new eEDM upper limit, which strongly constrains the allowed magnitude of CP-violation in Higgs couplings and hence the feasibility of electroweak baryogenesis (EWBG), were released by the ACME collaboration in 2013. We point out: if both the CP-odd Higgs-photon-photon ($Z$ boson) and the CP-odd Higgs-electron-positron couplings are turned on, a cancellation may occur either between the contributions of a CP-mixing Higgs boson, with the other Higgs bosons being decoupled, or between the contributions of a CP-even and a CP-odd Higgs bosons. With the assistance of the cancellation mechanisms, a large CP-phase in Higgs couplings with viable electroweak baryogenesis (EWBG) is still allowed. The reopened parameter regions would be probed by the future neutron, mercury EDM measurements, and direct measurements of Higgs CP-properties at the LHC and future colliders.
0705.1531
Fran\c{c}ois Gelis
A. Bessa, C.A.A. de Carvalho, E.S. Fraga, F. Gelis
Semiclassical thermodynamics of scalar fields
24 pages, 5 postscript figures
JHEP 0708:007,2007
10.1088/1126-6708/2007/08/007
CERN-PH-TH/2007-076
hep-ph
null
We present a systematic semiclassical procedure to compute the partition function for scalar field theories at finite temperature. The central objects in our scheme are the solutions of the classical equations of motion in imaginary time, with spatially independent boundary conditions. Field fluctuations -- both field deviations around these classical solutions, and fluctuations of the boundary value of the fields -- are resummed in a Gaussian approximation. In our final expression for the partition function, this resummation is reduced to solving certain ordinary differential equations. Moreover, we show that it is renormalizable with the usual 1-loop counterterms.
[ { "created": "Thu, 10 May 2007 18:57:02 GMT", "version": "v1" } ]
2010-02-03
[ [ "Bessa", "A.", "" ], [ "de Carvalho", "C. A. A.", "" ], [ "Fraga", "E. S.", "" ], [ "Gelis", "F.", "" ] ]
We present a systematic semiclassical procedure to compute the partition function for scalar field theories at finite temperature. The central objects in our scheme are the solutions of the classical equations of motion in imaginary time, with spatially independent boundary conditions. Field fluctuations -- both field deviations around these classical solutions, and fluctuations of the boundary value of the fields -- are resummed in a Gaussian approximation. In our final expression for the partition function, this resummation is reduced to solving certain ordinary differential equations. Moreover, we show that it is renormalizable with the usual 1-loop counterterms.
1607.08328
Sanjeev Kumar Verma
Radha Raman Gautam and Sanjeev Kumar
Zeros in the magic neutrino mass matrix
9 pages, 3 figures, minor changes as reported in Erratum: Zeros in the magic neutrino mass matrix [Phys. Rev. D 94, 036004 (2016)] (some typographical errors in two equations and a table corrected, results and conclusions unaffected)
Phys. Rev. D 94, 036004 (2016)
10.1103/PhysRevD.94.036004
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the phenomenological implications of the presence of two zeros in a magic neutrino mass matrix. We find that only two such patterns of the neutrino mass matrix are experimentally acceptable. We express all the neutrino observables as functions of one unknown phase $\phi$ and two known parameters $\Delta m^{2}_{12}$, $r=\Delta m^{2}_{12}/\Delta m^{2}_{23}$. In particular, we find $\sin^2 \theta_{13}=(2/3)r/(1+r)$. We also present a mass model for the allowed textures based upon the group $A_{4}$ using type I+II see-saw mechanism.
[ { "created": "Thu, 28 Jul 2016 06:40:20 GMT", "version": "v1" }, { "created": "Wed, 24 Aug 2016 10:09:52 GMT", "version": "v2" }, { "created": "Sun, 27 Dec 2020 14:56:53 GMT", "version": "v3" } ]
2020-12-29
[ [ "Gautam", "Radha Raman", "" ], [ "Kumar", "Sanjeev", "" ] ]
We study the phenomenological implications of the presence of two zeros in a magic neutrino mass matrix. We find that only two such patterns of the neutrino mass matrix are experimentally acceptable. We express all the neutrino observables as functions of one unknown phase $\phi$ and two known parameters $\Delta m^{2}_{12}$, $r=\Delta m^{2}_{12}/\Delta m^{2}_{23}$. In particular, we find $\sin^2 \theta_{13}=(2/3)r/(1+r)$. We also present a mass model for the allowed textures based upon the group $A_{4}$ using type I+II see-saw mechanism.
hep-ph/9412314
Engelhardt Michael
Michael Engelhardt
QCD_{1+1} at large N_F and N_C
7 revtex pages, 2 postscript figures appended
Nucl.Phys.B440:543-554,1995
10.1016/0550-3213(95)00030-V
null
hep-ph
null
QCD in 1+1 dimensions is examined in the limit of a large number of colors and flavors. The Hamiltonian matrix is given in a Fock space spanned by 't Hooft meson states and, for the case of zero fermion mass, a submatrix is diagonalized numerically to give the low-lying spectrum as a function of $N_F /N_C $. Pair creation effects generate bound states which are complicated mixtures of components of different meson number. There are a number of nontrivial zero modes; in the massive part of the spectrum some states tend to a well-defined $N_F \gg N_C $ limit while others become unstable and disappear. The masses of most states remain remarkably constant over a large range of $N_F /N_C $.
[ { "created": "Mon, 19 Dec 1994 09:02:16 GMT", "version": "v1" } ]
2010-11-01
[ [ "Engelhardt", "Michael", "" ] ]
QCD in 1+1 dimensions is examined in the limit of a large number of colors and flavors. The Hamiltonian matrix is given in a Fock space spanned by 't Hooft meson states and, for the case of zero fermion mass, a submatrix is diagonalized numerically to give the low-lying spectrum as a function of $N_F /N_C $. Pair creation effects generate bound states which are complicated mixtures of components of different meson number. There are a number of nontrivial zero modes; in the massive part of the spectrum some states tend to a well-defined $N_F \gg N_C $ limit while others become unstable and disappear. The masses of most states remain remarkably constant over a large range of $N_F /N_C $.
1702.07236
Tomohiro Abe
Tomohiro Abe
Effect of CP violation in the singlet-doublet dark matter model
13 pages, 5 figures, version accepted by PLB
null
10.1016/j.physletb.2017.05.048
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We revisit the singlet-doublet dark matter model with a special emphasis on the effect of CP violation on the dark matter phenomenology. The CP violation in the dark sector induces a pseudoscalar interaction of a fermionic dark matter candidate with the SM Higgs boson. The pseudoscalar interaction helps the dark matter candidate evade the strong constraints from the dark matter direct detection experiments. We show that the model can explain the measured value of the dark matter density even if dark matter direct detection experiments do not observe any signal. We also show that the electron electric dipole moment is an important complement to the direct detection for testing this model. Its value is smaller than the current upper bound but within the reach of future experiments.
[ { "created": "Thu, 23 Feb 2017 14:41:39 GMT", "version": "v1" }, { "created": "Fri, 26 May 2017 09:52:35 GMT", "version": "v2" } ]
2017-05-29
[ [ "Abe", "Tomohiro", "" ] ]
We revisit the singlet-doublet dark matter model with a special emphasis on the effect of CP violation on the dark matter phenomenology. The CP violation in the dark sector induces a pseudoscalar interaction of a fermionic dark matter candidate with the SM Higgs boson. The pseudoscalar interaction helps the dark matter candidate evade the strong constraints from the dark matter direct detection experiments. We show that the model can explain the measured value of the dark matter density even if dark matter direct detection experiments do not observe any signal. We also show that the electron electric dipole moment is an important complement to the direct detection for testing this model. Its value is smaller than the current upper bound but within the reach of future experiments.
1312.6858
A. B. Balantekin
A.B.Balantekin, N. Vassh (Wisconsin U., Madison)
Magnetic moments of active and sterile neutrinos
11 pages of LaTeX, 8 figures
null
10.1103/PhysRevD.89.073013
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Since most of the neutrino parameters are well-measured, we illustrate precisely the prediction of the Standard Model, minimally extended to allow massive neutrinos, for the electron neutrino magnetic moment. We elaborate on the effects of light sterile neutrinos on the effective electron neutrino magnetic moment measured at the reactors. We explicitly show that the kinematical effects of the neutrino masses are negligible even for light sterile neutrinos.
[ { "created": "Tue, 24 Dec 2013 17:27:45 GMT", "version": "v1" }, { "created": "Fri, 4 Apr 2014 20:47:29 GMT", "version": "v2" } ]
2015-06-18
[ [ "Balantekin", "A. B.", "", "Wisconsin U., Madison" ], [ "Vassh", "N.", "", "Wisconsin U., Madison" ] ]
Since most of the neutrino parameters are well-measured, we illustrate precisely the prediction of the Standard Model, minimally extended to allow massive neutrinos, for the electron neutrino magnetic moment. We elaborate on the effects of light sterile neutrinos on the effective electron neutrino magnetic moment measured at the reactors. We explicitly show that the kinematical effects of the neutrino masses are negligible even for light sterile neutrinos.
1803.07492
Tanmoy Modak
Masaya Kohda, Tanmoy Modak, Abner Soffer
Identifying a $Z'$ behind $b \to s \ell \ell$ anomalies at the LHC
explanations and references added, matches with the published version
Phys. Rev. D 97, 115019 (2018)
10.1103/PhysRevD.97.115019
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Recent $b\to s\ell\ell$ anomalies may imply the existence of a new $Z'$ boson with left-handed $Z'bs$ and $Z'\mu\mu$ couplings. Such a $Z'$ may be directly observed at LHC via $b \bar s \to Z' \to \mu^+\mu^-$, and its relevance to $b\to s\ell\ell$ may be studied by searching for the process $gs \to Z'b \to \mu^+\mu^- b$. In this paper, we analyze the capability of the 14 TeV LHC to observe the $Z'$ in the $\mu^+ \mu^-$ and $\mu^+\mu^- b$ modes based on an effective model with major phenomenological constraints imposed. We find that both modes can be discovered with 3000 fb$^{-1}$ data if the $Z'bs$ coupling saturates the latest $B_s-\bar B_s$ mixing limit from UTfit at around $2\sigma$. Besides, a tiny right-handed $Z'bs$ coupling, if it exists, opens up the possibility of a relatively large left-handed counterpart, due to cancellation in the $B_s-\bar B_s$ mixing amplitude. In this case, we show that even a data sample of $\mathcal{O}(100)$ fb$^{-1}$ would enable discovery of both modes. We further study the impact of a $Z'bb$ coupling as large as the $Z'bs$ coupling. This scenario enables discovery of the $Z'$ in both modes with milder effects on the $B_s-\bar B_s$ mixing, but obscures the relevance of the $Z'$ to $b \to s\ell\ell$. Discrimination between the $Z'bs$ and $Z'bb$ couplings may come from the production cross section for the $Z'b\bar{b}$ final state. However, we do not find the prospect for this to be promising.
[ { "created": "Tue, 20 Mar 2018 15:42:14 GMT", "version": "v1" }, { "created": "Thu, 14 Jun 2018 15:23:24 GMT", "version": "v2" } ]
2018-06-20
[ [ "Kohda", "Masaya", "" ], [ "Modak", "Tanmoy", "" ], [ "Soffer", "Abner", "" ] ]
Recent $b\to s\ell\ell$ anomalies may imply the existence of a new $Z'$ boson with left-handed $Z'bs$ and $Z'\mu\mu$ couplings. Such a $Z'$ may be directly observed at LHC via $b \bar s \to Z' \to \mu^+\mu^-$, and its relevance to $b\to s\ell\ell$ may be studied by searching for the process $gs \to Z'b \to \mu^+\mu^- b$. In this paper, we analyze the capability of the 14 TeV LHC to observe the $Z'$ in the $\mu^+ \mu^-$ and $\mu^+\mu^- b$ modes based on an effective model with major phenomenological constraints imposed. We find that both modes can be discovered with 3000 fb$^{-1}$ data if the $Z'bs$ coupling saturates the latest $B_s-\bar B_s$ mixing limit from UTfit at around $2\sigma$. Besides, a tiny right-handed $Z'bs$ coupling, if it exists, opens up the possibility of a relatively large left-handed counterpart, due to cancellation in the $B_s-\bar B_s$ mixing amplitude. In this case, we show that even a data sample of $\mathcal{O}(100)$ fb$^{-1}$ would enable discovery of both modes. We further study the impact of a $Z'bb$ coupling as large as the $Z'bs$ coupling. This scenario enables discovery of the $Z'$ in both modes with milder effects on the $B_s-\bar B_s$ mixing, but obscures the relevance of the $Z'$ to $b \to s\ell\ell$. Discrimination between the $Z'bs$ and $Z'bb$ couplings may come from the production cross section for the $Z'b\bar{b}$ final state. However, we do not find the prospect for this to be promising.
1404.4302
Nikolaos Kidonakis
Nikolaos Kidonakis and Richard J. Gonsalves
NNLO soft-gluon corrections for the Z-boson and W-boson transverse momentum distributions
17 pages, 14 figures
Phys.Rev.D89:094022,2014
10.1103/PhysRevD.89.094022
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present results for the $Z$-boson and $W$-boson transverse momentum ($p_T$) distributions for large $p_T$ at LHC and Tevatron energies. We calculate complete next-to-leading-order (NLO) QCD corrections as well as soft-gluon corrections at next-to-next-to-leading-order (NNLO) to the differential cross section. The NNLO soft-gluon contributions are derived from next-to-next-to-leading-logarithm (NNLL) resummation at two loops. We find enhancements of the $p_T$ distributions and reductions of the scale dependence when the NNLO corrections are included.
[ { "created": "Wed, 16 Apr 2014 16:17:26 GMT", "version": "v1" } ]
2015-06-19
[ [ "Kidonakis", "Nikolaos", "" ], [ "Gonsalves", "Richard J.", "" ] ]
We present results for the $Z$-boson and $W$-boson transverse momentum ($p_T$) distributions for large $p_T$ at LHC and Tevatron energies. We calculate complete next-to-leading-order (NLO) QCD corrections as well as soft-gluon corrections at next-to-next-to-leading-order (NNLO) to the differential cross section. The NNLO soft-gluon contributions are derived from next-to-next-to-leading-logarithm (NNLL) resummation at two loops. We find enhancements of the $p_T$ distributions and reductions of the scale dependence when the NNLO corrections are included.
2011.02919
Kazem Azizi
K. Azizi, A. R. Olamaei, S. Rostami
Strong interaction of doubly heavy spin-3/2 baryons with light vector mesons
29 Pages, 6 Figures and 5 Tables
null
10.1140/epjc/s10052-020-08770-6
null
hep-ph hep-ex hep-lat
http://creativecommons.org/licenses/by/4.0/
We calculate the strong coupling constants among the doubly heavy spin-$ \frac{3}{2} $ baryons $\Xi^*_{QQ}$ and $\Omega^*_{QQ}$, with $ Q $ and $ Q' $ being $ c$ or $ b $ quark, with light vector meson by means of the light-cone QCD sum rules. The matrix elements defining these vertices are described by four coupling constants $ g_1$, $ g_2$, $ g_3$, and $ g_4 $. The unwanted pollution coming from the doubly heavy spin-$ \frac{1}{2} $ baryons are removed by a special ordering of Dirac matrices and selection of appropriate Lorentz structures. The strong coupling constants are basic parameters that carry information on the nature of the strong interaction among hadronic multiplets. Investigation of these parameters may help physicists in the construction of the strong potentials among the doubly heavy baryons and light vector mesons. The values obtained for the strong coupling constants may also help experimental groups in analyses of the data produced at various hadron colliders.
[ { "created": "Thu, 5 Nov 2020 15:46:11 GMT", "version": "v1" }, { "created": "Mon, 14 Dec 2020 09:20:38 GMT", "version": "v2" } ]
2021-02-03
[ [ "Azizi", "K.", "" ], [ "Olamaei", "A. R.", "" ], [ "Rostami", "S.", "" ] ]
We calculate the strong coupling constants among the doubly heavy spin-$ \frac{3}{2} $ baryons $\Xi^*_{QQ}$ and $\Omega^*_{QQ}$, with $ Q $ and $ Q' $ being $ c$ or $ b $ quark, with light vector meson by means of the light-cone QCD sum rules. The matrix elements defining these vertices are described by four coupling constants $ g_1$, $ g_2$, $ g_3$, and $ g_4 $. The unwanted pollution coming from the doubly heavy spin-$ \frac{1}{2} $ baryons are removed by a special ordering of Dirac matrices and selection of appropriate Lorentz structures. The strong coupling constants are basic parameters that carry information on the nature of the strong interaction among hadronic multiplets. Investigation of these parameters may help physicists in the construction of the strong potentials among the doubly heavy baryons and light vector mesons. The values obtained for the strong coupling constants may also help experimental groups in analyses of the data produced at various hadron colliders.
hep-ph/0212345
Carl Shakin
Bing He, Hu Li, C. M. Shakin, and Qing Sun
Calculation of Temperature-Dependent Hadronic Correlation Functions of Pseudoscalar and Vector Currents
25 pages, 13 figures, Revtex4, additional figures
Phys.Rev. D67 (2003) 114012
10.1103/PhysRevD.67.114012
BCCNT: 02/121/318
hep-ph hep-lat
null
We make use of the Nambu-Jona-Lasinio (NJL) formalism and real-time finite-temperature field theory to calculate hadronic current correlation functions in the deconfined phase of quantum chromodynamics (QCD). We consider both pseudoscalar and vector currents and compare our results with those obtained in lattice simulations of QCD. Our results are similar to those obtained in the lattice simulations for $T=1.5 T_c$, where $T_c$ is the temperature of the confinement-deconfinement transition. For $T=3.0 T_c$ our results do not exhibit the resonances obtained from the lattice simulations. However, the errors presented for the lattice results are large and it is possible that our results at $T=3.0 T_c$ are consistent with the lattice results when these errors are taken into account. Since the method used in the lattice analysis to obtain the spectral functions requires assumptions about the likelihood of a particular form for the spectral function, we believe our calculations will be useful to researchers who wish to calculate hadronic current correlation functions at finite temperature using lattice-based methods. Our model makes use of temperature-dependent coupling constants for the NJL model. We present an argument that such temperature dependence is necessary, if the results of the model are to be consistent with what is known concerning QCD thermodynamics.
[ { "created": "Mon, 23 Dec 2002 18:16:08 GMT", "version": "v1" }, { "created": "Fri, 27 Dec 2002 15:28:00 GMT", "version": "v2" }, { "created": "Thu, 13 Feb 2003 17:51:14 GMT", "version": "v3" } ]
2009-11-07
[ [ "He", "Bing", "" ], [ "Li", "Hu", "" ], [ "Shakin", "C. M.", "" ], [ "Sun", "Qing", "" ] ]
We make use of the Nambu-Jona-Lasinio (NJL) formalism and real-time finite-temperature field theory to calculate hadronic current correlation functions in the deconfined phase of quantum chromodynamics (QCD). We consider both pseudoscalar and vector currents and compare our results with those obtained in lattice simulations of QCD. Our results are similar to those obtained in the lattice simulations for $T=1.5 T_c$, where $T_c$ is the temperature of the confinement-deconfinement transition. For $T=3.0 T_c$ our results do not exhibit the resonances obtained from the lattice simulations. However, the errors presented for the lattice results are large and it is possible that our results at $T=3.0 T_c$ are consistent with the lattice results when these errors are taken into account. Since the method used in the lattice analysis to obtain the spectral functions requires assumptions about the likelihood of a particular form for the spectral function, we believe our calculations will be useful to researchers who wish to calculate hadronic current correlation functions at finite temperature using lattice-based methods. Our model makes use of temperature-dependent coupling constants for the NJL model. We present an argument that such temperature dependence is necessary, if the results of the model are to be consistent with what is known concerning QCD thermodynamics.
hep-ph/0202008
Fuming Liu
F.M. Liu, J.Aichelin, M.Bleicher, H.J. Drescher, S. Ostapchenko, T. Pierog, K. Werner
Constraints on Models for Proton-Proton Scattering from Multi-strange Baryon Data
8 pages, 17 figures
Phys. Rev. D67, 034011 (2003)
10.1103/PhysRevD.67.034011
null
hep-ph
null
The recent data on pp collisions at 158 GeV provide severe constraints on string models: These measurements allow for the first time to determine how color strings are formed in ultrarelativistic proton-proton collisions.
[ { "created": "Fri, 1 Feb 2002 19:53:22 GMT", "version": "v1" }, { "created": "Tue, 25 Jun 2002 18:00:39 GMT", "version": "v2" }, { "created": "Tue, 18 Feb 2003 10:26:52 GMT", "version": "v3" } ]
2009-11-07
[ [ "Liu", "F. M.", "" ], [ "Aichelin", "J.", "" ], [ "Bleicher", "M.", "" ], [ "Drescher", "H. J.", "" ], [ "Ostapchenko", "S.", "" ], [ "Pierog", "T.", "" ], [ "Werner", "K.", "" ] ]
The recent data on pp collisions at 158 GeV provide severe constraints on string models: These measurements allow for the first time to determine how color strings are formed in ultrarelativistic proton-proton collisions.
1601.05746
Mario E. Gomez
Mario E. G\'omez, Sven Heinemeyer and Muhammad Rehman
Effects of Sfermion Mixing induced by RGE in the CMSSM
Talk given at LFC15: physics prospects for Linear and other Future Colliders after the discovery of the Higgs. 7-11 September 2015, ECT*, Trento, Italy
null
null
UHU-FISUM/2016-3
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Even within the Constrained Minimal Supersymmetric Standard Model (CMSSM) it is possible to induce sfermion flavor mixing through the Renormalization Group Equations (RGE) when the full structure of the Yukawa couplings is considered. We analyse the impact of including those effects on the accurate computation of $B$-physics observables, electroweak precision observables (EWPO) and the Higgs boson mass predictions.
[ { "created": "Thu, 21 Jan 2016 18:42:13 GMT", "version": "v1" } ]
2016-01-22
[ [ "Gómez", "Mario E.", "" ], [ "Heinemeyer", "Sven", "" ], [ "Rehman", "Muhammad", "" ] ]
Even within the Constrained Minimal Supersymmetric Standard Model (CMSSM) it is possible to induce sfermion flavor mixing through the Renormalization Group Equations (RGE) when the full structure of the Yukawa couplings is considered. We analyse the impact of including those effects on the accurate computation of $B$-physics observables, electroweak precision observables (EWPO) and the Higgs boson mass predictions.
1802.06880
Stefan Clementz
Mattias Blennow, Stefan Clementz, Juan Herrero-Garcia
The distribution of inelastic dark matter in the Sun
28 pages, 10 figures. v3: Errata: Bug fixed with some important changes to the conclusions
Eur.Phys.J. C78 (2018) no.5, 386
10.1140/epjc/s10052-018-5863-4
IFT-UAM/CSIC-18-019, ADP-18-4/T1052
hep-ph astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
If dark matter is composed of new particles, these may become captured after scattering with nuclei in the Sun, thermalise through additional scattering, and finally annihilate into neutrinos that can be detected on Earth. If dark matter scatters inelastically into a slightly heavier ($\mathcal{O} (10-100)$ keV) state it is unclear whether thermalisation occurs. One issue is that up-scattering from the lower mass state may be kinematically forbidden, at which point the thermalisation process effectively stops. A larger evaporation rate is also expected due to down-scattering. In this work, we perform a numerical simulation of the capture and thermalisation process in order to study the evolution of the dark matter distribution. We then calculate and compare the annihilation rate with that of the often assumed Maxwell--Boltzmann distribution. We also check if equilibrium between capture and annihilation is reached and find that this assumption definitely breaks down in a part of the explored parameter space. We also find that evaporation induced by down-scattering is not effective in reducing the total dark matter abundance.
[ { "created": "Mon, 19 Feb 2018 22:12:22 GMT", "version": "v1" }, { "created": "Wed, 23 May 2018 12:51:21 GMT", "version": "v2" }, { "created": "Wed, 8 May 2019 10:29:44 GMT", "version": "v3" } ]
2019-05-09
[ [ "Blennow", "Mattias", "" ], [ "Clementz", "Stefan", "" ], [ "Herrero-Garcia", "Juan", "" ] ]
If dark matter is composed of new particles, these may become captured after scattering with nuclei in the Sun, thermalise through additional scattering, and finally annihilate into neutrinos that can be detected on Earth. If dark matter scatters inelastically into a slightly heavier ($\mathcal{O} (10-100)$ keV) state it is unclear whether thermalisation occurs. One issue is that up-scattering from the lower mass state may be kinematically forbidden, at which point the thermalisation process effectively stops. A larger evaporation rate is also expected due to down-scattering. In this work, we perform a numerical simulation of the capture and thermalisation process in order to study the evolution of the dark matter distribution. We then calculate and compare the annihilation rate with that of the often assumed Maxwell--Boltzmann distribution. We also check if equilibrium between capture and annihilation is reached and find that this assumption definitely breaks down in a part of the explored parameter space. We also find that evaporation induced by down-scattering is not effective in reducing the total dark matter abundance.
2107.06082
James Wells
James D. Wells
Evaluation and Utility of Wilsonian Naturalness
21 pages
null
null
null
hep-ph hep-th physics.hist-ph
http://creativecommons.org/licenses/by/4.0/
We demonstrate that many Naturalness tests of particle theories discussed in the literature can be reformulated as straightforward algorithmic finetuning assessments in the matching of Wilsonian effective theories above and below particle mass thresholds. Implications of this EFT formulation of Wilsonian Naturalness are discussed for several theories, including the Standard Model, heavy singlet scalar theory, supersymmetry, Grand Unified Theories, twin Higgs theories, and theories of extra dimensions. We argue that the Wilsonian Naturalness algorithm presented here constitutes an unambiguous, a priori, and meaningful test that the Standard Model passes and which "the next good theory" of particle physics is very likely to pass.
[ { "created": "Mon, 5 Jul 2021 18:02:02 GMT", "version": "v1" } ]
2021-07-14
[ [ "Wells", "James D.", "" ] ]
We demonstrate that many Naturalness tests of particle theories discussed in the literature can be reformulated as straightforward algorithmic finetuning assessments in the matching of Wilsonian effective theories above and below particle mass thresholds. Implications of this EFT formulation of Wilsonian Naturalness are discussed for several theories, including the Standard Model, heavy singlet scalar theory, supersymmetry, Grand Unified Theories, twin Higgs theories, and theories of extra dimensions. We argue that the Wilsonian Naturalness algorithm presented here constitutes an unambiguous, a priori, and meaningful test that the Standard Model passes and which "the next good theory" of particle physics is very likely to pass.
1709.02930
Amir N. Khan
Amir N. Khan
$\sin ^{2}\theta _{W}$ estimate and neutrino electromagnetic properties from low-energy solar data
5 pages, 2 figures, 2 tables, Solar flux and oscillation parameter uncertainties in predictions were included. Statistical model modified. Slight changes occured in numerical results, Published in JPhyG
J. Phys. G: Nucl. Part. Phys. 46 035005, 2019
10.1088/1361-6471/ab0057
FERMILAB-PUB-18-444-ND-T
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We report new values of weak-mixing angle ($\sin ^{2}\theta _{W}$)$,$ neutrino effective magnetic moment and the charge radius using the lowest-energy (to-date) solar neutrino data of pp, $^{7}$Be and pep spectra from phase-I and phase-II runs of Borexino experiment. The best-fit values are $\sin ^{2}\theta _{W}=$0.235$\pm $0.019 with a precision comparable to that of the combined reactor and accelerator very short-baseline experiments and $\mu _{\nu }^{eff}\leq 8.7\times 10^{-12}\mu _{B}$ at 90% C.L. with a factor of 3 improvement than the previous bounds. This leads to the improvement of all the related magnetic moment matrix elements for the Majorana-type and Dirac-type in mass basis and also improvement on bounds on the flavor magnetic moment states. The bounds on the neutrino charged radii turn out to be $-0.82\times 10^{-32}$cm$^{2}\leq \left \langle r_{\nu _{e}}^{2}\right \rangle \ \leq 1.27\times 10^{-32}$ cm$^{2}\ $and $-9\times 10^{-32}$cm$^{2}\leq \left \langle r_{\nu _{\mu },\nu _{\tau }}^{2}\right \rangle \ \leq 3.1\times 10^{-31}$ cm$^{2}\ $ at 90% C.L..
[ { "created": "Sat, 9 Sep 2017 08:54:01 GMT", "version": "v1" }, { "created": "Fri, 10 Aug 2018 05:28:19 GMT", "version": "v2" }, { "created": "Sun, 17 Feb 2019 23:18:45 GMT", "version": "v3" } ]
2019-02-19
[ [ "Khan", "Amir N.", "" ] ]
We report new values of weak-mixing angle ($\sin ^{2}\theta _{W}$)$,$ neutrino effective magnetic moment and the charge radius using the lowest-energy (to-date) solar neutrino data of pp, $^{7}$Be and pep spectra from phase-I and phase-II runs of Borexino experiment. The best-fit values are $\sin ^{2}\theta _{W}=$0.235$\pm $0.019 with a precision comparable to that of the combined reactor and accelerator very short-baseline experiments and $\mu _{\nu }^{eff}\leq 8.7\times 10^{-12}\mu _{B}$ at 90% C.L. with a factor of 3 improvement than the previous bounds. This leads to the improvement of all the related magnetic moment matrix elements for the Majorana-type and Dirac-type in mass basis and also improvement on bounds on the flavor magnetic moment states. The bounds on the neutrino charged radii turn out to be $-0.82\times 10^{-32}$cm$^{2}\leq \left \langle r_{\nu _{e}}^{2}\right \rangle \ \leq 1.27\times 10^{-32}$ cm$^{2}\ $and $-9\times 10^{-32}$cm$^{2}\leq \left \langle r_{\nu _{\mu },\nu _{\tau }}^{2}\right \rangle \ \leq 3.1\times 10^{-31}$ cm$^{2}\ $ at 90% C.L..
0709.2259
Vladimir Saleev Anatolievich
V. A. Saleev and D. V. Vasin
Charmonium Polarization in High Energy Collisions
Talk presented at XI Workshop on High Energy Spin Physics, JINR, Dubna, 2005
Proc.of XI Workshop on High Energy Spin Physics, Dubna, Sept. 27, 2005: p.133-138, JINR(2006)
null
null
hep-ph
null
We consider charmonium polarization at high-energy hadron collider Tevatron in the framework of the nonrelativistic QCD (NRQCD) and the k_T-factorization approach. The polarization effects are studied for the direct and the prompt production channels. The obtained predictions can be used to test the Regge limit of QCD and the NRQCD formalism.
[ { "created": "Fri, 14 Sep 2007 11:19:20 GMT", "version": "v1" } ]
2007-09-17
[ [ "Saleev", "V. A.", "" ], [ "Vasin", "D. V.", "" ] ]
We consider charmonium polarization at high-energy hadron collider Tevatron in the framework of the nonrelativistic QCD (NRQCD) and the k_T-factorization approach. The polarization effects are studied for the direct and the prompt production channels. The obtained predictions can be used to test the Regge limit of QCD and the NRQCD formalism.
1412.4651
Marie Bo\"er
Marie Bo\"er and Michel Guidal
Generalized Parton Distributions and Deeply Virtual Compton Scattering
17 pages, 7 figures, to appear in JPhysG
null
10.1088/0954-3899/42/3/034023
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a method which allows to extract theoretical informations out of a limited set of experimental data and observables, forming up in general an under- constrained system. It has been applied to the field of nucleon structure, in the domain of Generalized Parton Distributions (GPDs). We take advantage of this review to remove a couple of approximations that we used in our previous works and update our results using the latest data published.
[ { "created": "Mon, 15 Dec 2014 16:02:52 GMT", "version": "v1" } ]
2015-06-23
[ [ "Boër", "Marie", "" ], [ "Guidal", "Michel", "" ] ]
We present a method which allows to extract theoretical informations out of a limited set of experimental data and observables, forming up in general an under- constrained system. It has been applied to the field of nucleon structure, in the domain of Generalized Parton Distributions (GPDs). We take advantage of this review to remove a couple of approximations that we used in our previous works and update our results using the latest data published.
1206.3865
Lei Wu
Junjie Cao, Chengcheng Han, Lei Wu, Jin Min Yang, Yang Zhang
Probing natural SUSY from stop pair production at the LHC
19 pages, 10 figures, version accepted by JHEP
null
10.1007/JHEP11(2012)039
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider the natural supersymmetry scenario in the framework of the R-parity conserving minimal supersymmetric standard model (called natural MSSM) and examine the observability of stop pair production at the LHC. We first scan the parameters of this scenario under various experimental constraints, including the SM-like Higgs boson mass, the indirect limits from precision electroweak data and B-decays. Then in the allowed parameter space we study the stop pair production at the LHC followed by the stop decay into a top quark plus a lightest neutralino or into a bottom quark plus a chargino. From detailed Monte Carlo simulations of the signals and backgrounds, we find the two decay modes are complementary to each other in probing the stop pair production, and the LHC with $\sqrt{s}= 14$ TeV and 100 $fb^{-1}$ luminosity is capable of discovering the stop predicted in natural MSSM up to 450 GeV. If no excess events were observed at the LHC, the 95% C.L. exclusion limits of the stop masses can reach around 537 GeV.
[ { "created": "Mon, 18 Jun 2012 09:27:51 GMT", "version": "v1" }, { "created": "Tue, 7 Aug 2012 10:29:40 GMT", "version": "v2" }, { "created": "Tue, 23 Oct 2012 09:21:38 GMT", "version": "v3" } ]
2015-06-05
[ [ "Cao", "Junjie", "" ], [ "Han", "Chengcheng", "" ], [ "Wu", "Lei", "" ], [ "Yang", "Jin Min", "" ], [ "Zhang", "Yang", "" ] ]
We consider the natural supersymmetry scenario in the framework of the R-parity conserving minimal supersymmetric standard model (called natural MSSM) and examine the observability of stop pair production at the LHC. We first scan the parameters of this scenario under various experimental constraints, including the SM-like Higgs boson mass, the indirect limits from precision electroweak data and B-decays. Then in the allowed parameter space we study the stop pair production at the LHC followed by the stop decay into a top quark plus a lightest neutralino or into a bottom quark plus a chargino. From detailed Monte Carlo simulations of the signals and backgrounds, we find the two decay modes are complementary to each other in probing the stop pair production, and the LHC with $\sqrt{s}= 14$ TeV and 100 $fb^{-1}$ luminosity is capable of discovering the stop predicted in natural MSSM up to 450 GeV. If no excess events were observed at the LHC, the 95% C.L. exclusion limits of the stop masses can reach around 537 GeV.
2107.12813
Francesca Chadha-Day
Francesca Chadha-Day
Axion-like particle oscillations
This is the Accepted Manuscript version of an article accepted for publication in Journal of Cosmology and Astroparticle Physics. IOP Publishing Ltd is not responsible for any errors in this version of the manuscript or any version derived from it. This Accepted Manuscript is published under a CC BY licence. The Version of Record is available at https://doi.org/10.1088/1475-7516/2022/01/013
JCAP01(2022)013
10.1088/1475-7516/2022/01/013
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
String theory compactifications may generate many light axion-like particles (ALPs) with weak couplings to electromagnetism. In general, a large number of ALPs may exist, with a linear combination having a potentially observable coupling to electromagnetism. The basis in which only one ALP couples to electromagnetism is in general misaligned with the mass basis. This leads to mixing between the `electromagnetic' ALP and a number of `hidden' ALPs that do not interact directly with the photon. The process is analagous to neutrino oscillations. I will discuss the phenomenological consequences of this mixing for astrophysical ALP signals, in particular showing that it may significantly reduce the predicted signal in experiments such as the CERN Axion Solar Telescope.
[ { "created": "Tue, 27 Jul 2021 13:35:08 GMT", "version": "v1" }, { "created": "Wed, 12 Jan 2022 13:57:48 GMT", "version": "v2" } ]
2022-01-13
[ [ "Chadha-Day", "Francesca", "" ] ]
String theory compactifications may generate many light axion-like particles (ALPs) with weak couplings to electromagnetism. In general, a large number of ALPs may exist, with a linear combination having a potentially observable coupling to electromagnetism. The basis in which only one ALP couples to electromagnetism is in general misaligned with the mass basis. This leads to mixing between the `electromagnetic' ALP and a number of `hidden' ALPs that do not interact directly with the photon. The process is analagous to neutrino oscillations. I will discuss the phenomenological consequences of this mixing for astrophysical ALP signals, in particular showing that it may significantly reduce the predicted signal in experiments such as the CERN Axion Solar Telescope.
hep-ph/9209238
Sean Carroll
W. Daniel Garretson, George B. Field, and Sean M. Carroll (Harvard-Smithsonian Center for Astrophysics)
Primordial magnetic fields from pseudo-Goldstone bosons
18 pages
Phys.Rev.D46:5346-5351,1992
10.1103/PhysRevD.46.5346
null
hep-ph astro-ph
null
The existence of large-scale magnetic fields in galaxies is well established, but there is no accepted mechanism for generating a primordial field which could grow into what is observed today. We discuss a model which attempts to account for the necessary primordial field by invoking a pseudo-Goldstone boson coupled to electromagnetism. The evolution of this boson during inflation generates a magnetic field; however, it seems difficult on rather general grounds to obtain fields of sufficient strength on astrophysically interesting scales.
[ { "created": "Tue, 15 Sep 1992 21:24:42 GMT", "version": "v1" } ]
2011-05-05
[ [ "Garretson", "W. Daniel", "", "Harvard-Smithsonian Center for Astrophysics" ], [ "Field", "George B.", "", "Harvard-Smithsonian Center for Astrophysics" ], [ "Carroll", "Sean M.", "", "Harvard-Smithsonian Center for Astrophysics" ] ]
The existence of large-scale magnetic fields in galaxies is well established, but there is no accepted mechanism for generating a primordial field which could grow into what is observed today. We discuss a model which attempts to account for the necessary primordial field by invoking a pseudo-Goldstone boson coupled to electromagnetism. The evolution of this boson during inflation generates a magnetic field; however, it seems difficult on rather general grounds to obtain fields of sufficient strength on astrophysically interesting scales.
1402.5317
Wayne W. Repko
Duane A. Dicus and Wayne W. Repko
Dalitz Decay $H\to\,f\bar{f}\gamma$ as a Background for $H\to\gamma\,\gamma$
3 pages, 1 figure, 2 tables
Phys. Rev. D 89, 093013 (2014)
10.1103/PhysRevD.89.093013
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Dalitz decay $H\to\,f\bar{f}\gamma$ is calculated for very small $f\bar{f}$ invariant masses where the $f\bar{f}$ pair could be mistaken for a photon in analysis of $H\to\gamma\gamma$ decays. Using the ATLAS cuts and the full Dalitz decay amplitude, we estimate this fraction to be 7.06%.
[ { "created": "Fri, 21 Feb 2014 15:03:33 GMT", "version": "v1" } ]
2014-05-21
[ [ "Dicus", "Duane A.", "" ], [ "Repko", "Wayne W.", "" ] ]
The Dalitz decay $H\to\,f\bar{f}\gamma$ is calculated for very small $f\bar{f}$ invariant masses where the $f\bar{f}$ pair could be mistaken for a photon in analysis of $H\to\gamma\gamma$ decays. Using the ATLAS cuts and the full Dalitz decay amplitude, we estimate this fraction to be 7.06%.
1001.5151
Adrian Carmona
Francisco del Aguila, Adrian Carmona, Jose Santiago
Neutrino Masses from an A4 Symmetry in Holographic Composite Higgs Models
39 pages, 1 figure
JHEP 1008:127,2010
10.1007/JHEP08(2010)127
CAFPE-128/10, UGFT-258/10
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We show that holographic composite Higgs Models with a discrete A4 symmetry naturally predict hierarchical charged lepton masses and an approximate tri-bimaximal lepton mixing with the correct scale of neutrino masses. They also satisfy current constraints from electroweak precision tests, lepton flavor violation and lepton mixing in a large region of parameter space. Two phenomenologically relevant features arise in these models. First, an extra suppression on the lepton Yukawa couplings makes the tau lepton more composite than naively expected from its mass. As a consequence new light leptonic resonances, with masses as low as few hundreds of GeV, large couplings to tau and a very characteristic collider phenomenology, are quite likely. Second, the discrete symmetry A4 together with the model structure provide a double-layer of flavor protection that allows to keep tree-level mediated processes below present experimental limits. One-loop processes violating lepton flavor, like mu -> e gamma, may be however observable at future experiments.
[ { "created": "Thu, 28 Jan 2010 11:16:33 GMT", "version": "v1" }, { "created": "Wed, 10 Feb 2010 17:08:03 GMT", "version": "v2" } ]
2014-11-20
[ [ "del Aguila", "Francisco", "" ], [ "Carmona", "Adrian", "" ], [ "Santiago", "Jose", "" ] ]
We show that holographic composite Higgs Models with a discrete A4 symmetry naturally predict hierarchical charged lepton masses and an approximate tri-bimaximal lepton mixing with the correct scale of neutrino masses. They also satisfy current constraints from electroweak precision tests, lepton flavor violation and lepton mixing in a large region of parameter space. Two phenomenologically relevant features arise in these models. First, an extra suppression on the lepton Yukawa couplings makes the tau lepton more composite than naively expected from its mass. As a consequence new light leptonic resonances, with masses as low as few hundreds of GeV, large couplings to tau and a very characteristic collider phenomenology, are quite likely. Second, the discrete symmetry A4 together with the model structure provide a double-layer of flavor protection that allows to keep tree-level mediated processes below present experimental limits. One-loop processes violating lepton flavor, like mu -> e gamma, may be however observable at future experiments.
hep-ph/0111337
Ira Z. Rothstein
Ira Z. Rothstein
Extracting V_{ub} Using the Radiative Decay Data
Presented at 9th International Symposium on Heavy Flavor Physics, Pasadena, California, 10-13 Sep 2001. 7 pages
AIP Conf.Proc. 618 (2002) 153-158
10.1063/1.1478832
null
hep-ph
null
In this talk I review recent progress made in extracting V_{ub} from the cut electron energy and hadronic mass spectra of inclusive B meson decays utilizing the data from radiative decays. It is shown that an extraction is possible without modeling the B meson structure function. I discuss the issues involving the assumptions of local duality in various extractions. I also comment on the recent CLEO extraction of V_{ub}.
[ { "created": "Tue, 27 Nov 2001 01:34:40 GMT", "version": "v1" } ]
2009-11-07
[ [ "Rothstein", "Ira Z.", "" ] ]
In this talk I review recent progress made in extracting V_{ub} from the cut electron energy and hadronic mass spectra of inclusive B meson decays utilizing the data from radiative decays. It is shown that an extraction is possible without modeling the B meson structure function. I discuss the issues involving the assumptions of local duality in various extractions. I also comment on the recent CLEO extraction of V_{ub}.
hep-ph/0204164
Ryuichiro Kitano
Ryuichiro Kitano
Small Dirac neutrino masses in supersymmetric grand unified theories
11 pages, 2 figures, references added, version to appear in Phys. Lett B
Phys.Lett.B539:102-106,2002
10.1016/S0370-2693(02)02067-1
TU-650
hep-ph
null
A simple mechanism to generate Dirac masses for the neutrinos in SU(5) supersymmetric grand unified theory is proposed. The tiny Dirac masses are induced by the small mixing between the Higgs fields and another superheavy fields. The mixing terms are obtained by the same mechanism as the mu-term generation of the order of the supersymmetry breaking scale, so that the mixing of order TeV / M_GUT \sim 10^{-13} is realized. We consider the lepton flavor violating processes in this model. The branching ratios are directly related to the neutrino oscillation parameters and we can predict the B(\tau -> \mu \gamma) / B(\mu -> e \gamma) ratio once the neutrino oscillation parameters are determined.
[ { "created": "Mon, 15 Apr 2002 08:36:02 GMT", "version": "v1" }, { "created": "Mon, 29 Apr 2002 05:36:31 GMT", "version": "v2" }, { "created": "Tue, 11 Jun 2002 02:44:17 GMT", "version": "v3" } ]
2014-11-17
[ [ "Kitano", "Ryuichiro", "" ] ]
A simple mechanism to generate Dirac masses for the neutrinos in SU(5) supersymmetric grand unified theory is proposed. The tiny Dirac masses are induced by the small mixing between the Higgs fields and another superheavy fields. The mixing terms are obtained by the same mechanism as the mu-term generation of the order of the supersymmetry breaking scale, so that the mixing of order TeV / M_GUT \sim 10^{-13} is realized. We consider the lepton flavor violating processes in this model. The branching ratios are directly related to the neutrino oscillation parameters and we can predict the B(\tau -> \mu \gamma) / B(\mu -> e \gamma) ratio once the neutrino oscillation parameters are determined.
1008.3562
Juan Antonio Aguilar-Saavedra
J. A. Aguilar-Saavedra
Effective four-fermion operators in top physics: a roadmap
LaTeX 43 pages, 1 PS figure. Cross sections for uu,cc -> tt corrected
Nucl.Phys.B843:638-672,2011; Erratum-ibid.B851:443-444,2011
10.1016/j.nuclphysb.2010.10.015 10.1016/j.nuclphysb.2011.06.003
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We write down a minimal basis for dimension-six gauge-invariant four-fermion operators, with some operator replacements with respect to previous ones which make it simpler for calculations. Using this basis we classify all four-fermion operator contributions involving one or two top quarks. Taking into account the different fermion chiralities, possible colour contractions and independent flavour combinations, a total number of 572 gauge-invariant operators are involved. We apply this to calculate all three-body top decay widths t -> d_k u_i dbar_j, t -> d_k e_i+ nu_j, t -> u_k u_i ubar_j, t -> u_k e_j+ e_i-, t -> u_k nu_j nu_i (with i,j,k generation indices) mediated by dimension-six four-fermion operators, including the interference with the Standard Model amplitudes when present. All single top production cross sections in pp, p pbar and e+ e- collisions are calculated as well, namely u_i d_k -> d_j t, dbar_j d_k -> ubar_i t, u_i dbar_j -> dbar_k t, u_i u_k -> u_j t, u_i ubar_j -> ubar_k t, e+ e- -> ubar_k t and the charge conjugate processes. We also compute all top pair production cross sections, ubar_i u_j -> t tbar, dbar_i d_j -> t tbar, u_i u_j -> t t and e+ e- -> t tbar. Our results are completely general, without assuming any particular relation among effective operator coefficients.
[ { "created": "Fri, 20 Aug 2010 20:00:07 GMT", "version": "v1" }, { "created": "Tue, 2 Nov 2010 14:17:20 GMT", "version": "v2" }, { "created": "Mon, 6 Jun 2011 11:23:01 GMT", "version": "v3" } ]
2011-07-13
[ [ "Aguilar-Saavedra", "J. A.", "" ] ]
We write down a minimal basis for dimension-six gauge-invariant four-fermion operators, with some operator replacements with respect to previous ones which make it simpler for calculations. Using this basis we classify all four-fermion operator contributions involving one or two top quarks. Taking into account the different fermion chiralities, possible colour contractions and independent flavour combinations, a total number of 572 gauge-invariant operators are involved. We apply this to calculate all three-body top decay widths t -> d_k u_i dbar_j, t -> d_k e_i+ nu_j, t -> u_k u_i ubar_j, t -> u_k e_j+ e_i-, t -> u_k nu_j nu_i (with i,j,k generation indices) mediated by dimension-six four-fermion operators, including the interference with the Standard Model amplitudes when present. All single top production cross sections in pp, p pbar and e+ e- collisions are calculated as well, namely u_i d_k -> d_j t, dbar_j d_k -> ubar_i t, u_i dbar_j -> dbar_k t, u_i u_k -> u_j t, u_i ubar_j -> ubar_k t, e+ e- -> ubar_k t and the charge conjugate processes. We also compute all top pair production cross sections, ubar_i u_j -> t tbar, dbar_i d_j -> t tbar, u_i u_j -> t t and e+ e- -> t tbar. Our results are completely general, without assuming any particular relation among effective operator coefficients.
2111.14178
Meijian Li
Yang Li, Meijian Li, James P. Vary
Two-photon transitions of charmonia on the light front
8 pages, 8 figures, 1 table
Phys. Rev. D 105, L071901, 2022
10.1103/PhysRevD.105.L071901
null
hep-ph nucl-th
http://creativecommons.org/licenses/by-nc-nd/4.0/
We investigate the two-photon transitions $H_{c\bar c} \to \gamma^*\gamma$ of the charmonium system in light-front dynamics. The light-front wave functions were obtained from solving the effective Hamiltonian based on light-front holography and one-gluon exchange interaction within the basis light-front quantization approach. We compute the two-photon transition form factors as well as the two-photon decay widths for S- and P-wave charmonia, $\eta_c$ and $\chi_{cJ}$ and their excitations. Without introducing any free parameters, our predictions are in good agreement with the recent experimental measurements by BaBar and Belle, shedding light on the relativistic nature of charmonium.
[ { "created": "Sun, 28 Nov 2021 15:30:11 GMT", "version": "v1" }, { "created": "Fri, 22 Apr 2022 10:23:39 GMT", "version": "v2" } ]
2022-04-25
[ [ "Li", "Yang", "" ], [ "Li", "Meijian", "" ], [ "Vary", "James P.", "" ] ]
We investigate the two-photon transitions $H_{c\bar c} \to \gamma^*\gamma$ of the charmonium system in light-front dynamics. The light-front wave functions were obtained from solving the effective Hamiltonian based on light-front holography and one-gluon exchange interaction within the basis light-front quantization approach. We compute the two-photon transition form factors as well as the two-photon decay widths for S- and P-wave charmonia, $\eta_c$ and $\chi_{cJ}$ and their excitations. Without introducing any free parameters, our predictions are in good agreement with the recent experimental measurements by BaBar and Belle, shedding light on the relativistic nature of charmonium.
hep-ph/9902367
Edoardo Di Napoli
Edoardo Di Napoli
The Nambu-Jona Lasinio mechanism and the electroweak symmetry breaking in the Standard Model
18 Pages, no figures, LaTex, corrected typos, references removed
null
null
null
hep-ph
null
This is a short report of the entire work developed during the study of the possible realizations of the "Top Mode" Standard Model. Here it is examined the breaking of internal symmetries from another point of view showing that is possible to reproduce the gauged electroweak panorama of the traditional Standard Model in a exhaustive and selfconsistent way. The result is reached applying the main futures of the Nambu-Jona Lasinio (NJL) mechanism to an electroweak invariant Lagrangian. In this context the use of functional formalism for composite operators naturally leads to a different dynamical approach. Meanwhile the Higgs mechanism acts on the Lagrangian form, a NJL like model looks directly at the physics of the system showing the real dynamical content hidden in the Green functions of the theory.
[ { "created": "Tue, 16 Feb 1999 18:35:46 GMT", "version": "v1" }, { "created": "Fri, 7 May 1999 12:05:10 GMT", "version": "v2" } ]
2007-05-23
[ [ "Di Napoli", "Edoardo", "" ] ]
This is a short report of the entire work developed during the study of the possible realizations of the "Top Mode" Standard Model. Here it is examined the breaking of internal symmetries from another point of view showing that is possible to reproduce the gauged electroweak panorama of the traditional Standard Model in a exhaustive and selfconsistent way. The result is reached applying the main futures of the Nambu-Jona Lasinio (NJL) mechanism to an electroweak invariant Lagrangian. In this context the use of functional formalism for composite operators naturally leads to a different dynamical approach. Meanwhile the Higgs mechanism acts on the Lagrangian form, a NJL like model looks directly at the physics of the system showing the real dynamical content hidden in the Green functions of the theory.
1010.3580
Domenec Espriu
Domenec Espriu and Albert Renau
Axions and Cosmic Rays
16 pages, 3 figures. To appear in Proceedings of the Quarks 2010 International Seminar, Kolomna, Russia
null
10.1007/s11232-012-0027-4
ICCUB-10-062, UB-ECM-PF-10-36
hep-ph astro-ph.CO astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate the propagation of a charged particle in a spatially constant but time dependent pseudoscalar background. Physically this pseudoscalar background could be provided by a relic axion density. The background leads to an explicit breaking of Lorentz invariance; as a consequence processes such as $p\to p \gamma$ or $e\to e \gamma$ are possible within some kinematical constraints. The phenomenon is described by the QED lagrangian extended with a Chern-Simons term that contains a 4-vector which characterizes the breaking of Lorentz invariance induced by the time-dependent background. While the radiation induced (similar to the Cherenkov effect) is too small to influence the propagation of cosmic rays in a significant way, the hypothetical detection of the photons radiated by high energy cosmic rays via this mechanism would provide an indirect way of verifying the cosmological relevance of axions. We discuss on the order of magnitude of the effect.
[ { "created": "Mon, 18 Oct 2010 12:35:01 GMT", "version": "v1" } ]
2015-05-20
[ [ "Espriu", "Domenec", "" ], [ "Renau", "Albert", "" ] ]
We investigate the propagation of a charged particle in a spatially constant but time dependent pseudoscalar background. Physically this pseudoscalar background could be provided by a relic axion density. The background leads to an explicit breaking of Lorentz invariance; as a consequence processes such as $p\to p \gamma$ or $e\to e \gamma$ are possible within some kinematical constraints. The phenomenon is described by the QED lagrangian extended with a Chern-Simons term that contains a 4-vector which characterizes the breaking of Lorentz invariance induced by the time-dependent background. While the radiation induced (similar to the Cherenkov effect) is too small to influence the propagation of cosmic rays in a significant way, the hypothetical detection of the photons radiated by high energy cosmic rays via this mechanism would provide an indirect way of verifying the cosmological relevance of axions. We discuss on the order of magnitude of the effect.
1205.5808
Matthew Reece
Zhenyu Han, Andrey Katz, David Krohn, and Matthew Reece
(Light) Stop Signs
28 pages, 16 figures; v2: references added, version published in JHEP
null
10.1007/JHEP08(2012)083
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Stop squarks with a mass just above the top's and which decay to a nearly massless LSP are difficult to probe because of the large SM di-top background. Here we discuss search strategies which could be used to set more stringent bounds in this difficult region. In particular, we note that both the rapidity difference Delta y(t,tbar) and spin correlations (inferred from, for example, Delta phi(l+,l-)) are sensitive to the presence of stops. We emphasize that systematic uncertainties in top quark production can confound analyses looking for stops, making theoretical and experimental progress on the understanding of Standard Model top production at high precision a very important task. We estimate that spin correlation alone, which is relatively robust against such systematic uncertainties, can exclude a 200 GeV stop at 95% confidence with 20 fb^-1 at the 8 TeV LHC.
[ { "created": "Fri, 25 May 2012 20:00:05 GMT", "version": "v1" }, { "created": "Tue, 23 Oct 2012 02:36:52 GMT", "version": "v2" } ]
2015-06-05
[ [ "Han", "Zhenyu", "" ], [ "Katz", "Andrey", "" ], [ "Krohn", "David", "" ], [ "Reece", "Matthew", "" ] ]
Stop squarks with a mass just above the top's and which decay to a nearly massless LSP are difficult to probe because of the large SM di-top background. Here we discuss search strategies which could be used to set more stringent bounds in this difficult region. In particular, we note that both the rapidity difference Delta y(t,tbar) and spin correlations (inferred from, for example, Delta phi(l+,l-)) are sensitive to the presence of stops. We emphasize that systematic uncertainties in top quark production can confound analyses looking for stops, making theoretical and experimental progress on the understanding of Standard Model top production at high precision a very important task. We estimate that spin correlation alone, which is relatively robust against such systematic uncertainties, can exclude a 200 GeV stop at 95% confidence with 20 fb^-1 at the 8 TeV LHC.
2001.06516
Ivan Ni\v{s}and\v{z}i\'c
Aliaksei Kachanovich, Ulrich Nierste, and Ivan Ni\v{s}and\v{z}i\'c
Higgs decay into a lepton pair and a photon revisited
17 pages, 8 figures, 2 ancillary files; v2: missed color factor added, plots and results changed accordingly, matches the corrected version to appear in PRD
Phys. Rev. D 101, 073003 (2020)
10.1103/PhysRevD.101.073003
TTP-20-002
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present new calculations of the differential decay rates for $H\to \ell^+\ell^- \gamma$ with $\ell=e$ or $\mu$ in the Standard Model. The branching fractions and forward-backward asymmetries, defined in terms of the flight direction of the photon relative to the lepton momenta, depend on the cuts on energies and invariant masses of the final state particles. For typical choices of these cuts we find the branching ratios $B(H\to e \bar e \gamma)=5.8\cdot 10^{-5}$ and $B(H\to \mu \bar \mu \gamma)=6.4\cdot 10^{-5}$ and the forward-backward asymmetries $\mathcal{A}^{(e)}_{\text{FB}}=0.343$ and $\mathcal{A}^{(\mu)}_{\text{FB}}=0.255$. We provide compact analytic expressions for the differential decay rates for the use in experimental analyses.
[ { "created": "Fri, 17 Jan 2020 20:20:52 GMT", "version": "v1" }, { "created": "Mon, 30 Nov 2020 20:06:11 GMT", "version": "v2" } ]
2020-12-02
[ [ "Kachanovich", "Aliaksei", "" ], [ "Nierste", "Ulrich", "" ], [ "Nišandžić", "Ivan", "" ] ]
We present new calculations of the differential decay rates for $H\to \ell^+\ell^- \gamma$ with $\ell=e$ or $\mu$ in the Standard Model. The branching fractions and forward-backward asymmetries, defined in terms of the flight direction of the photon relative to the lepton momenta, depend on the cuts on energies and invariant masses of the final state particles. For typical choices of these cuts we find the branching ratios $B(H\to e \bar e \gamma)=5.8\cdot 10^{-5}$ and $B(H\to \mu \bar \mu \gamma)=6.4\cdot 10^{-5}$ and the forward-backward asymmetries $\mathcal{A}^{(e)}_{\text{FB}}=0.343$ and $\mathcal{A}^{(\mu)}_{\text{FB}}=0.255$. We provide compact analytic expressions for the differential decay rates for the use in experimental analyses.
hep-ph/9903216
Peter Lichard
Peter Lichard (Department of Physics and Astronomy, University of Pittsburgh, USA and Institute of Physics, Silesian University, Czech Republic)
Running mass of the rho0 meson's implication for the dilepton mass spectrum and the mu+mu-/e+e- branching ratio in the K+ --> pi+l+l- decays
13 pages, RevTeX, epsf.sty, 4 embedded figures
Phys.Rev. D60 (1999) 053007
10.1103/PhysRevD.60.053007
null
hep-ph
null
We make an attempt to resolve the discrepancy of the observed e+e- mass spectrum in the K+ --> pi+e+e- decay with that predicted by meson dominance. To this end we investigate the properties of the rho0 propagator. We use dispersion relations to evaluate the running mass squared m_rho^2(t) of the rho0 resonance without adjustable parameters. To improve the convergence of the dispersion integral, the momentum dependence of strong vertices is taken from the flux-tube-breaking model of Kokoski and Isgur. The obtained behavior of m_rho^2(t) at small momentum squared t makes the K+ --> pi+e+e- form factor rise faster with increasing $t$ than in the original meson-dominance calculation and more in agreement with the published data. As a consequence, the meson-dominance prediction of the mu+mu-/e+e- branching ratio changes slightly, from 0.224 to 0.236. We do not see any possibility to accommodate into the meson-dominance approach an even steeper e+e- spectrum, indicated by the preliminary data of the E865 collaboration at BNL AGS.
[ { "created": "Mon, 1 Mar 1999 16:48:10 GMT", "version": "v1" } ]
2009-10-31
[ [ "Lichard", "Peter", "", "Department of Physics and Astronomy, University of\n Pittsburgh, USA and Institute of Physics, Silesian University, Czech\n Republic" ] ]
We make an attempt to resolve the discrepancy of the observed e+e- mass spectrum in the K+ --> pi+e+e- decay with that predicted by meson dominance. To this end we investigate the properties of the rho0 propagator. We use dispersion relations to evaluate the running mass squared m_rho^2(t) of the rho0 resonance without adjustable parameters. To improve the convergence of the dispersion integral, the momentum dependence of strong vertices is taken from the flux-tube-breaking model of Kokoski and Isgur. The obtained behavior of m_rho^2(t) at small momentum squared t makes the K+ --> pi+e+e- form factor rise faster with increasing $t$ than in the original meson-dominance calculation and more in agreement with the published data. As a consequence, the meson-dominance prediction of the mu+mu-/e+e- branching ratio changes slightly, from 0.224 to 0.236. We do not see any possibility to accommodate into the meson-dominance approach an even steeper e+e- spectrum, indicated by the preliminary data of the E865 collaboration at BNL AGS.
1801.10503
Sonali Patnaik
Sonali Patnaik, P.C. Dash, Susmita Kar and N.Barik
Electromagnetic transitions of $(b{\bar c})$ bound system
arXiv admin note: text overlap with arXiv:1710.08242
Phys. Rev. D 97, 056025 (2018)
10.1103/PhysRevD.97.056025
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study electromagnetic transitions: $B_c^*(ns)\to B_c(ns) e^+ e^-$, $B_c^*(ns)\to B_c(n^{\prime}s) e^+ e^-$ and $B_c(ns)\to B^*_c(n^{\prime}s) e^+ e^-$ in the relativistic independent quark (RIQ) model based on a flavor-independent potential in the scalar-vector harmonic form. The transition form factors for energetically possible transitions involving $B_c$ - and $B_c^*$- mesons in ground as well as orbitally excited states are predicted in their respective kinematic range. Our predictions on decay width for the allowed and hindered transitions are found compatible with those of the model calculations based on Bethe-Salpeter approach. Predictions in this sector would not only provide more information about members of the $B_c$-family including mass splitting between vector mesons and corresponding pseudoscalar counterparts but give hints for experimental determination of unknown masses of other excited $B_c$ - and ground state of $B_c^*$-meson, which is expected at LHCb and $Z^0$ factory in near future.
[ { "created": "Tue, 30 Jan 2018 13:59:34 GMT", "version": "v1" } ]
2018-04-04
[ [ "Patnaik", "Sonali", "" ], [ "Dash", "P. C.", "" ], [ "Kar", "Susmita", "" ], [ "Barik", "N.", "" ] ]
We study electromagnetic transitions: $B_c^*(ns)\to B_c(ns) e^+ e^-$, $B_c^*(ns)\to B_c(n^{\prime}s) e^+ e^-$ and $B_c(ns)\to B^*_c(n^{\prime}s) e^+ e^-$ in the relativistic independent quark (RIQ) model based on a flavor-independent potential in the scalar-vector harmonic form. The transition form factors for energetically possible transitions involving $B_c$ - and $B_c^*$- mesons in ground as well as orbitally excited states are predicted in their respective kinematic range. Our predictions on decay width for the allowed and hindered transitions are found compatible with those of the model calculations based on Bethe-Salpeter approach. Predictions in this sector would not only provide more information about members of the $B_c$-family including mass splitting between vector mesons and corresponding pseudoscalar counterparts but give hints for experimental determination of unknown masses of other excited $B_c$ - and ground state of $B_c^*$-meson, which is expected at LHCb and $Z^0$ factory in near future.
2208.03375
John M. Yelton
John M Yelton
CP Violation in Charmed and Bottom Baryon Physics
contribution to the 20th Conference on Flavor Physics and CP Violation, Oxford, MS, 2022
null
null
null
hep-ph hep-ex
http://creativecommons.org/licenses/by/4.0/
This is an experimentalist's view of the recent results on, and prospects for, CP Violation in charmed and bottom baryons
[ { "created": "Fri, 5 Aug 2022 20:08:27 GMT", "version": "v1" } ]
2022-08-09
[ [ "Yelton", "John M", "" ] ]
This is an experimentalist's view of the recent results on, and prospects for, CP Violation in charmed and bottom baryons
1207.5391
Emanuele Re
Rikkert Frederix, Emanuele Re, Paolo Torrielli
Single-top t-channel hadroproduction in the four-flavour scheme with POWHEG and aMC@NLO
16+1 pages, 8 figures, matches version accepted for publication in JHEP
null
10.1007/JHEP09(2012)130
ZU-TH 14/12; IPPP/12/54; DCPT/12/108; CERN-PH-TH/2012-206; LPN12-084; MCnet/12/10
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present results for the QCD next-to-leading order (NLO) calculation of single-top t-channel production in the 4-flavour scheme, interfaced to Parton Shower (PS) Monte Carlo programs according to the POWHEG and MC@NLO methods. Comparisons between the two methods, as well as with the corresponding process in the 5-flavour scheme are presented. For the first time results for typical kinematic distributions of the spectator-b jet are presented in an NLO+PS approach.
[ { "created": "Mon, 23 Jul 2012 13:45:41 GMT", "version": "v1" }, { "created": "Tue, 2 Oct 2012 15:17:47 GMT", "version": "v2" } ]
2015-06-05
[ [ "Frederix", "Rikkert", "" ], [ "Re", "Emanuele", "" ], [ "Torrielli", "Paolo", "" ] ]
We present results for the QCD next-to-leading order (NLO) calculation of single-top t-channel production in the 4-flavour scheme, interfaced to Parton Shower (PS) Monte Carlo programs according to the POWHEG and MC@NLO methods. Comparisons between the two methods, as well as with the corresponding process in the 5-flavour scheme are presented. For the first time results for typical kinematic distributions of the spectator-b jet are presented in an NLO+PS approach.
1410.0234
Piotr Lebiedowicz
Piotr Lebiedowicz, Otto Nachtmann, Antoni Szczurek
Exclusive central diffractive production of scalar, pseudoscalar and vector mesons
5 pages, presented by P. Lebiedowicz at MESON2014, Krak\'ow, Poland, 29 May - 3 June 2014
null
10.1051/epjconf/20148105018
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We discuss exclusive central diffractive production of scalar ($f_{0}(980)$, $f_{0}(1370)$, $f_{0}(1500)$), pseudoscalar ($\eta$, $\eta'(958)$), and vector ($\rho^{0}$) mesons in proton-proton collisions. The amplitudes are formulated in terms of effective vertices required to respect standard rules of Quantum Field Theory and propagators for the exchanged pomeron and reggeons. Different pomeron-pomeron-meson tensorial (vectorial) coupling structures are possible in general. In most cases two lowest orbital angular momentum - spin couplings are necessary to describe experimental differential distributions. For the $f_{0}(980)$ and $\eta$ production the reggeon-pomeron, pomeron-reggeon, and reggeon-reggeon exchanges are included in addition, which seems to be necessary at relatively low energies. The theoretical results are compared with the WA102 experimental data, in order to determine the model parameters. For the $\rho^{0}$ production the photon-pomeron and pomeron-photon exchanges are considered. The coupling parameters of tensor pomeron and/or reggeon are fixed from the H1 and ZEUS experimental data of the $\gamma p \to \rho^{0} p$ reaction. We present first predictions of this mechanism for $pp \to pp \pi^{+} \pi^{-}$ reaction being studied at COMPASS, RHIC, Tevatron, and LHC. Correlation in azimuthal angle between outgoing protons and distribution in pion rapidities at $\sqrt{s} = 7$TeV are presented. We show that high-energy central production of mesons could provide crucial information on the spin structure of the soft pomeron.
[ { "created": "Wed, 1 Oct 2014 14:14:05 GMT", "version": "v1" } ]
2015-06-23
[ [ "Lebiedowicz", "Piotr", "" ], [ "Nachtmann", "Otto", "" ], [ "Szczurek", "Antoni", "" ] ]
We discuss exclusive central diffractive production of scalar ($f_{0}(980)$, $f_{0}(1370)$, $f_{0}(1500)$), pseudoscalar ($\eta$, $\eta'(958)$), and vector ($\rho^{0}$) mesons in proton-proton collisions. The amplitudes are formulated in terms of effective vertices required to respect standard rules of Quantum Field Theory and propagators for the exchanged pomeron and reggeons. Different pomeron-pomeron-meson tensorial (vectorial) coupling structures are possible in general. In most cases two lowest orbital angular momentum - spin couplings are necessary to describe experimental differential distributions. For the $f_{0}(980)$ and $\eta$ production the reggeon-pomeron, pomeron-reggeon, and reggeon-reggeon exchanges are included in addition, which seems to be necessary at relatively low energies. The theoretical results are compared with the WA102 experimental data, in order to determine the model parameters. For the $\rho^{0}$ production the photon-pomeron and pomeron-photon exchanges are considered. The coupling parameters of tensor pomeron and/or reggeon are fixed from the H1 and ZEUS experimental data of the $\gamma p \to \rho^{0} p$ reaction. We present first predictions of this mechanism for $pp \to pp \pi^{+} \pi^{-}$ reaction being studied at COMPASS, RHIC, Tevatron, and LHC. Correlation in azimuthal angle between outgoing protons and distribution in pion rapidities at $\sqrt{s} = 7$TeV are presented. We show that high-energy central production of mesons could provide crucial information on the spin structure of the soft pomeron.
1401.7858
Ma Yong-Liang
Yong-Liang Ma
Dense baryonic matter in the hidden local symmetry approach
Contribution to the proceedings of XV International Conference on Hadron Spectroscopy (Hadron 2013), November 4-8 2013, Nara, Japan
null
null
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The dense baryonic matter and hadron properties in medium were simulated by using a Skyrme model including the ground state vector mesons introduced from the hidden local symmetry approach up to the next to leading order. We found that both the $\rho$ and $\omega$ mesons affect the baryonic matter and medium modified hadron properties dramatically. The most remarkable observation is that, the pion decay constant and the nucleon mass have the similar density dependence which agrees with the large $N_c$ argument. Explicitly, they drop with increasing density in the Skyrmion phase and stop decreasing at $n_{1/2}^{}$ at which the skyrmions in medium fractionize into half-skyrmions and remains nearly constants in the half-skyrmion phase. This density dependence in the half-skyrmion phase indicates that, although $\langle \bar{q}q\rangle \neq 0$ on average in this phase, chiral symmetry is not restored since hadrons are still massive and there exist pions. In addition, the nearly constant nucleon mass means that it could has a non-vanishing component up to the chiral transition, which might shed light on the origin of the nucleon mass.
[ { "created": "Thu, 30 Jan 2014 14:28:24 GMT", "version": "v1" } ]
2014-01-31
[ [ "Ma", "Yong-Liang", "" ] ]
The dense baryonic matter and hadron properties in medium were simulated by using a Skyrme model including the ground state vector mesons introduced from the hidden local symmetry approach up to the next to leading order. We found that both the $\rho$ and $\omega$ mesons affect the baryonic matter and medium modified hadron properties dramatically. The most remarkable observation is that, the pion decay constant and the nucleon mass have the similar density dependence which agrees with the large $N_c$ argument. Explicitly, they drop with increasing density in the Skyrmion phase and stop decreasing at $n_{1/2}^{}$ at which the skyrmions in medium fractionize into half-skyrmions and remains nearly constants in the half-skyrmion phase. This density dependence in the half-skyrmion phase indicates that, although $\langle \bar{q}q\rangle \neq 0$ on average in this phase, chiral symmetry is not restored since hadrons are still massive and there exist pions. In addition, the nearly constant nucleon mass means that it could has a non-vanishing component up to the chiral transition, which might shed light on the origin of the nucleon mass.
1408.1518
Norihito Toyota
Kanji Fujii and Norihito Toyota
Expectation values of flavor-neutrino numbers with respect to neutrino-source hadron states --Neutrino oscillations and decay probabilities--
15 pages, 5 figures
null
10.1093/ptep/ptu178
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
On the basis of quantum field theory, we consider a unified description of various processes accompanied by neutrinos, namely weak decays and oscillation processes. The structures of the expectation values of flavor-neutrino numbers with respect to neutrino-source hadron state are investigated. Due to the smallness of neutrino masses, we naturally obtain the old (i.e. pre-mixing) formulas of decay probabilities. Together, it is shown that the oscillation formulas, similar to the usual ones, are applied irrespectively of the details of neutrino-producing processes. The derived oscillation formulas are the same in form as the usually used ones except for the oscillation length.
[ { "created": "Thu, 7 Aug 2014 09:14:10 GMT", "version": "v1" }, { "created": "Sat, 9 Aug 2014 05:52:26 GMT", "version": "v2" } ]
2015-02-04
[ [ "Fujii", "Kanji", "" ], [ "Toyota", "Norihito", "" ] ]
On the basis of quantum field theory, we consider a unified description of various processes accompanied by neutrinos, namely weak decays and oscillation processes. The structures of the expectation values of flavor-neutrino numbers with respect to neutrino-source hadron state are investigated. Due to the smallness of neutrino masses, we naturally obtain the old (i.e. pre-mixing) formulas of decay probabilities. Together, it is shown that the oscillation formulas, similar to the usual ones, are applied irrespectively of the details of neutrino-producing processes. The derived oscillation formulas are the same in form as the usually used ones except for the oscillation length.