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hep-ph/0203215
Roberto Ugoccioni
Alberto Giovannini, Roberto Ugoccioni
Global event properties in proton-proton physics with ALICE
11 pages, 5 ps figures; contribution to ALICE PPR
null
null
DFTT 29/2001
hep-ph
null
ALICE is a unique opportunity for studying low Pt physics and minimum bias events, and consequently for hunting substructures in strong interactions. The general question concerning global event properties in pp and ppbar physics is indeed whether substructures can be seen in the data in a model-independent way. In other terms, can we identify the interface between perturbative and non-perturbative regimes?
[ { "created": "Fri, 22 Mar 2002 14:28:16 GMT", "version": "v1" } ]
2007-05-23
[ [ "Giovannini", "Alberto", "" ], [ "Ugoccioni", "Roberto", "" ] ]
ALICE is a unique opportunity for studying low Pt physics and minimum bias events, and consequently for hunting substructures in strong interactions. The general question concerning global event properties in pp and ppbar physics is indeed whether substructures can be seen in the data in a model-independent way. In other terms, can we identify the interface between perturbative and non-perturbative regimes?
0808.2236
Urjit A. Yajnik
U. A. Yajnik
Cosmology for Particle Physicists
54 pages pdf, 8 figures, Lectures at SERC School on Theoretical High Energy Physics, PRL Ahmedabad, February 2006
Surveys in Theoretical High Energy Physics -2, pp. 187-262, R. Rangarajan and M. Sivakumar ed.s, Hindustan Book Agency 2014
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In these notes we present a selection of topics, each section approximately amounting to one lecture. We begin with a brief recapitulation of General Relativity, and the Standard Model of Cosmology. This is followed by lectures on important signatures of the remote past. These include : (i) inflation, (ii) density perturbations leading to galaxy formation, (iii) study of hot and cold relics decoupled from the remaining constituents, some of which can be candidates for Dark Matter, (iv) baryon asymmetry of the Universe.
[ { "created": "Sat, 16 Aug 2008 05:34:27 GMT", "version": "v1" } ]
2014-11-14
[ [ "Yajnik", "U. A.", "" ] ]
In these notes we present a selection of topics, each section approximately amounting to one lecture. We begin with a brief recapitulation of General Relativity, and the Standard Model of Cosmology. This is followed by lectures on important signatures of the remote past. These include : (i) inflation, (ii) density perturbations leading to galaxy formation, (iii) study of hot and cold relics decoupled from the remaining constituents, some of which can be candidates for Dark Matter, (iv) baryon asymmetry of the Universe.
1606.09046
Piotr Lebiedowicz
Piotr Lebiedowicz, Otto Nachtmann, Antoni Szczurek
Exclusive diffractive production of $\pi^+ \pi^-$ pairs within tensor pomeron approach
6 pages, 3 figures, presented by P. Lebiedowicz at DIS2016, 11-15 April 2016, DESY Hamburg, Germany
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We discuss exclusive central diffractive production of $\pi^{+} \pi^{-}$ in proton-(anti)proton collisions at high energies. Based on a tensor pomeron model we present results of the purely diffractive dipion continuum, the scalar $f_{0}(500)$, $f_{0}(980)$ and tensor $f_{2}(1270)$ resonances decaying into the $\pi^{+} \pi^{-}$ pairs as well as the photoproduction mechanism ($\rho^{0}$, Drell-S\"oding). We discuss how two pomerons couple to the tensor meson $f_{2}(1270)$ and the interference effects of resonance and dipion continuum contributions. The theoretical results are compared with existing STAR, CDF, and CMS experimental data. Predictions for planned or being carried out experiments (ALICE, ATLAS) are presented. We find that the relative contribution of resonant $f_2(1270)$ and dipion continuum strongly depend on the cut on proton transverse momenta (or four-momentum transfer squared $t_{1,2}$) which may explain some controversial observations made by different ISR experiments in the past. The cuts may play then the role of a $\pi \pi$ resonance filter.
[ { "created": "Wed, 29 Jun 2016 11:18:03 GMT", "version": "v1" } ]
2016-06-30
[ [ "Lebiedowicz", "Piotr", "" ], [ "Nachtmann", "Otto", "" ], [ "Szczurek", "Antoni", "" ] ]
We discuss exclusive central diffractive production of $\pi^{+} \pi^{-}$ in proton-(anti)proton collisions at high energies. Based on a tensor pomeron model we present results of the purely diffractive dipion continuum, the scalar $f_{0}(500)$, $f_{0}(980)$ and tensor $f_{2}(1270)$ resonances decaying into the $\pi^{+} \pi^{-}$ pairs as well as the photoproduction mechanism ($\rho^{0}$, Drell-S\"oding). We discuss how two pomerons couple to the tensor meson $f_{2}(1270)$ and the interference effects of resonance and dipion continuum contributions. The theoretical results are compared with existing STAR, CDF, and CMS experimental data. Predictions for planned or being carried out experiments (ALICE, ATLAS) are presented. We find that the relative contribution of resonant $f_2(1270)$ and dipion continuum strongly depend on the cut on proton transverse momenta (or four-momentum transfer squared $t_{1,2}$) which may explain some controversial observations made by different ISR experiments in the past. The cuts may play then the role of a $\pi \pi$ resonance filter.
2309.03889
Hong-Yi Zhang
Hong-Yi Zhang, Ray Hagimoto and Andrew J. Long
Neutron star cooling with lepton-flavor-violating axions
v3: Matching the published version; an exclusion plot is added; 5+8 pages, 3+6 figures
null
null
null
hep-ph astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The cores of dense stars are a powerful laboratory for studying feebly coupled particles such as axions. Some of the strongest constraints on axionlike particles and their couplings to ordinary matter derive from considerations of stellar axion emission. In this work we study the radiation of axionlike particles from degenerate neutron star matter via a lepton-flavor-violating coupling that leads to muon-electron conversion when an axion is emitted. We calculate the axion emission rate per unit volume (emissivity) and by comparing with the rate of neutrino emission, we infer upper limits on the lepton-flavor-violating coupling that are at the level of $|g_{ae\mu}| \lesssim 10^{-6}$. For the hotter environment of a supernova, such as SN 1987A, the axion emission rate is enhanced and the limit is stronger, at the level of $|g_{ae\mu}| \lesssim 10^{-11}$, competitive with laboratory limits. Interestingly, our derivation of the axion emissivity reveals that axion emission via the lepton-flavor-violating coupling is suppressed relative to the familiar lepton-flavor-preserving channels by the square of the plasma temperature to muon mass ratio, which is responsible for the relatively weaker limits.
[ { "created": "Thu, 7 Sep 2023 17:52:25 GMT", "version": "v1" }, { "created": "Tue, 7 Nov 2023 18:55:18 GMT", "version": "v2" }, { "created": "Sat, 27 Apr 2024 03:27:52 GMT", "version": "v3" } ]
2024-04-30
[ [ "Zhang", "Hong-Yi", "" ], [ "Hagimoto", "Ray", "" ], [ "Long", "Andrew J.", "" ] ]
The cores of dense stars are a powerful laboratory for studying feebly coupled particles such as axions. Some of the strongest constraints on axionlike particles and their couplings to ordinary matter derive from considerations of stellar axion emission. In this work we study the radiation of axionlike particles from degenerate neutron star matter via a lepton-flavor-violating coupling that leads to muon-electron conversion when an axion is emitted. We calculate the axion emission rate per unit volume (emissivity) and by comparing with the rate of neutrino emission, we infer upper limits on the lepton-flavor-violating coupling that are at the level of $|g_{ae\mu}| \lesssim 10^{-6}$. For the hotter environment of a supernova, such as SN 1987A, the axion emission rate is enhanced and the limit is stronger, at the level of $|g_{ae\mu}| \lesssim 10^{-11}$, competitive with laboratory limits. Interestingly, our derivation of the axion emissivity reveals that axion emission via the lepton-flavor-violating coupling is suppressed relative to the familiar lepton-flavor-preserving channels by the square of the plasma temperature to muon mass ratio, which is responsible for the relatively weaker limits.
1309.2555
Vladimir Kopeliovich Benedikt
Vladimir B. Kopeliovich (Moscow, INR & Moscow, MIPT)
Effective Strange Quark/Antiquark Masses from the Chiral Soliton Models for Baryons
12 pp, 4 tables; extended and modified contribution to the 10th Conference on Quark Confinement and the Hadron Spectrum (Confinement X) : Munich, Germany, October 8-12, 2012. Published in PoS ConfinementX (2012) 305 Conference: C12-10-08.1, p.305 Proceedings. Based on the papers Phys.Part.Nucl. 37 (2006) 623, Phys.Rev. D73 (2006) 094018, JETP 108 (2009) 770
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The effective strange quark and antiquark masses are estimated from the chiral soliton approach (CSA) results for the spectrum of exotic and nonexotic baryons. There are problems when one tries to project results of the CSA on the simple quark models (QM): the parameter in $1/N_c$ expansion is so large for the case of the baryon spectrum that extrapolation to the real $N_c=3$ world is not possible; rigid (as well soft) rotator model and the bound state model coincide in the first two orders in $1/N_c$, but differ in the next orders. There is correspondence of the CSA and simple QM predictions for pentaquarks (PQ) spectra in negative $S$ sector of the $\{27\}$ and $\{35\}$-plets: the effective mass of strange quark is about $135 -130\,MeV$, slightly smaller for $\{35\}$. For positive strangeness components the link between CSA and QM requires strong dependence of the effective $\bar{s}$ mass on particular SU(3) multiplet. The SU(3) configuration mixing is important, it pushes the spectrum towards the simplistic model (with equal masses of the strange quark and antiquark), and explanation of this nice property is lacking still. The success of the CSA in describing many properties of baryons and light nuclei (hypernuclei) means that predictions of pentaquark states should be considered seriously. Existence of PQ by itself is without any doubt, although very narrow PQ may not exist. Wide, even very wide PQ should exist, therefore, searches for PQ remain to be an actual task.
[ { "created": "Tue, 10 Sep 2013 15:52:43 GMT", "version": "v1" } ]
2013-09-11
[ [ "Kopeliovich", "Vladimir B.", "", "Moscow, INR & Moscow, MIPT" ] ]
The effective strange quark and antiquark masses are estimated from the chiral soliton approach (CSA) results for the spectrum of exotic and nonexotic baryons. There are problems when one tries to project results of the CSA on the simple quark models (QM): the parameter in $1/N_c$ expansion is so large for the case of the baryon spectrum that extrapolation to the real $N_c=3$ world is not possible; rigid (as well soft) rotator model and the bound state model coincide in the first two orders in $1/N_c$, but differ in the next orders. There is correspondence of the CSA and simple QM predictions for pentaquarks (PQ) spectra in negative $S$ sector of the $\{27\}$ and $\{35\}$-plets: the effective mass of strange quark is about $135 -130\,MeV$, slightly smaller for $\{35\}$. For positive strangeness components the link between CSA and QM requires strong dependence of the effective $\bar{s}$ mass on particular SU(3) multiplet. The SU(3) configuration mixing is important, it pushes the spectrum towards the simplistic model (with equal masses of the strange quark and antiquark), and explanation of this nice property is lacking still. The success of the CSA in describing many properties of baryons and light nuclei (hypernuclei) means that predictions of pentaquark states should be considered seriously. Existence of PQ by itself is without any doubt, although very narrow PQ may not exist. Wide, even very wide PQ should exist, therefore, searches for PQ remain to be an actual task.
hep-ph/9912339
Fernando Marroquim Leao de Almeida Jr.
F. M. L. de Almeida Jr and J. A. Martins Simoes
On bottom mixing with exotic quarks
6 pages, 2 Tables, LaTeX
JHEP0003:025,2000
10.1088/1126-6708/2000/03/025
null
hep-ph
null
In this paper we present a calculation of the effects of bottom mixing with new exotic quarks in the forward-backward and left-right asymmetries, the bottom branching ratio and the QCD coupling constant. A global fit with the recent data on these quantities is done and stringent bounds are obtained. We discuss the effects of different isospin signatures for the new possible exotic quarks. The consequences for superstrig-inspired $E_6$ models are discussed. Constraints on the bottom mixing with the isosinglet quarks of the fundamental 27-plet are presented.
[ { "created": "Tue, 14 Dec 1999 15:56:52 GMT", "version": "v1" } ]
2009-10-31
[ [ "Almeida", "F. M. L. de", "Jr" ], [ "Simoes", "J. A. Martins", "" ] ]
In this paper we present a calculation of the effects of bottom mixing with new exotic quarks in the forward-backward and left-right asymmetries, the bottom branching ratio and the QCD coupling constant. A global fit with the recent data on these quantities is done and stringent bounds are obtained. We discuss the effects of different isospin signatures for the new possible exotic quarks. The consequences for superstrig-inspired $E_6$ models are discussed. Constraints on the bottom mixing with the isosinglet quarks of the fundamental 27-plet are presented.
hep-ph/9708429
Yoav Achiman
Yoav Achiman
Massive Neutrinos and Lepton Mixing in Unified Theories
8 pages, Talk presented at the XVI International Workshop on Weak Interactions and Neutrinos, Capri, 1997
Nucl.Phys.Proc.Suppl. 66 (1998) 400-403
10.1016/S0920-5632(98)00073-5
WU B 97-23
hep-ph
null
The recent GUT (x SUSY) models which can predict the neutrino properties are reviewed.
[ { "created": "Thu, 21 Aug 1997 19:16:47 GMT", "version": "v1" } ]
2009-10-30
[ [ "Achiman", "Yoav", "" ] ]
The recent GUT (x SUSY) models which can predict the neutrino properties are reviewed.
2010.13122
Xuxu Yang
Xu-Xu Yang, Hang Zhou, Tian-Peng Tang and Ning Liu
Mono-top signature from stop decay at the HE-LHC
11 pages, 4 figures, 2 tables
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Searching for the top squark (stop) is a key task to test the naturalness of SUSY. Different from stop pair production, single stop production relies on its electroweak properties and can provide some unique signatures. Following the single production process $pp \to \tilde t_1 \tilde{\chi}^-_1 \to t \tilde{\chi}^0_1 \tilde{\chi}^-_1$, the top quark has two decay channels: leptonic channel and hadronic channel. In this paper, we probe the observability of these two channels in a simplified MSSM scenario. We find that, at the 27 TeV LHC with the integrated luminosity of ${\cal L} = 15~\text{ab}^{-1}$, $m_{\tilde{t}_1}<1900$ GeV and $\mu<750$ GeV can be excluded at $2\sigma$ through the leptonic mono-top channel, while $m_{\tilde{t}_1}<1200$ GeV and $\mu<350$ GeV can be excluded at $2\sigma$ through the hadronic channel.
[ { "created": "Sun, 25 Oct 2020 13:51:01 GMT", "version": "v1" } ]
2020-10-27
[ [ "Yang", "Xu-Xu", "" ], [ "Zhou", "Hang", "" ], [ "Tang", "Tian-Peng", "" ], [ "Liu", "Ning", "" ] ]
Searching for the top squark (stop) is a key task to test the naturalness of SUSY. Different from stop pair production, single stop production relies on its electroweak properties and can provide some unique signatures. Following the single production process $pp \to \tilde t_1 \tilde{\chi}^-_1 \to t \tilde{\chi}^0_1 \tilde{\chi}^-_1$, the top quark has two decay channels: leptonic channel and hadronic channel. In this paper, we probe the observability of these two channels in a simplified MSSM scenario. We find that, at the 27 TeV LHC with the integrated luminosity of ${\cal L} = 15~\text{ab}^{-1}$, $m_{\tilde{t}_1}<1900$ GeV and $\mu<750$ GeV can be excluded at $2\sigma$ through the leptonic mono-top channel, while $m_{\tilde{t}_1}<1200$ GeV and $\mu<350$ GeV can be excluded at $2\sigma$ through the hadronic channel.
0707.2010
Giancarlo Ferrera
Ugo Aglietti (Rome U. & INFN, Rome), Leonardo Di Giustino (Parma U. & INFN, Parma), Giancarlo Ferrera (Barcelona U. & Florence U.), Alessandro Renzaglia (Rome U. & INFN, Rome), Giulia Ricciardi (Naples U. & INFN, Naples), Luca Trentadue (Parma U. & INFN, Parma)
Threshold Resummation in B --> X_c l nu_l Decays
24 pages, no figures
Phys.Lett.B653:38-52,2007
10.1016/j.physletb.2007.07.041
ROME1/1455-07, DSF/23/2007
hep-ph
null
We compute the QCD form factor resumming threshold logarithms in B --> X_c + l + nu_l decays to next-to-leading logarithmic approximation. We present an interpolation formula including soft as well as collinear effects softened by the non-vanishing charm mass.
[ { "created": "Fri, 13 Jul 2007 17:20:32 GMT", "version": "v1" } ]
2008-11-26
[ [ "Aglietti", "Ugo", "", "Rome U. & INFN, Rome" ], [ "Di Giustino", "Leonardo", "", "Parma U. &\n INFN, Parma" ], [ "Ferrera", "Giancarlo", "", "Barcelona U. & Florence U." ], [ "Renzaglia", "Alessandro", "", "Rome U. & INFN, Rome" ], [ "Ricciardi", "Giulia", "", "Naples U. & INFN,\n Naples" ], [ "Trentadue", "Luca", "", "Parma U. & INFN, Parma" ] ]
We compute the QCD form factor resumming threshold logarithms in B --> X_c + l + nu_l decays to next-to-leading logarithmic approximation. We present an interpolation formula including soft as well as collinear effects softened by the non-vanishing charm mass.
hep-ph/0504222
Lars Fromme
Lars Fromme
Electroweak Baryogenesis with dimension-6 Higgs interactions
10 pages, 4 figures, Talk given at the 8th International Moscow School of Physics
Surveys High Energ.Phys. 19 (2004) 193-201
10.1080/01422410500160212
BI-TP 2005/14
hep-ph
null
We present the computation of the baryon asymmetry in the SM amplified by dimension-6 Higgs interactions using the WKB approximation. Analyzing the one-loop potential it turns out that the phase transition is strongly first order in a wide range of the parameters. It is ensured not to wash out the net baryon number gained previously even for Higgs masses up to at least 170 GeV. In addition dimension-6 operators induce new sources of CP violation. Novel source terms which enhance the generated baryon asymmetry emerge in the transport equations. This model predicts a baryon to entropy ratio close to the observed value for a large part of the parameter space.
[ { "created": "Mon, 25 Apr 2005 16:04:50 GMT", "version": "v1" } ]
2015-06-25
[ [ "Fromme", "Lars", "" ] ]
We present the computation of the baryon asymmetry in the SM amplified by dimension-6 Higgs interactions using the WKB approximation. Analyzing the one-loop potential it turns out that the phase transition is strongly first order in a wide range of the parameters. It is ensured not to wash out the net baryon number gained previously even for Higgs masses up to at least 170 GeV. In addition dimension-6 operators induce new sources of CP violation. Novel source terms which enhance the generated baryon asymmetry emerge in the transport equations. This model predicts a baryon to entropy ratio close to the observed value for a large part of the parameter space.
1212.3415
Gergely Fejos
G. Fejos
Chiral symmetry breaking patterns in the U_L(n)xU_R(n) meson model
ReVTeX4, 11 pages, 2 figures. Discussion on the stability of the potential included
Phys.Rev.D87:056006,2013
10.1103/PhysRevD.87.056006
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Chiral symmetry breaking patterns are investigated in the U_L(n)xU_R(n) meson model. It is shown that new classes of minima of the effective potential belonging to the center of the Lie algebra exist for arbitrary flavor number n. The true ground state of the system is searched nonperturbatively and although multiple local minima of the effective potential may exist, it is argued that in regions of the parameter space applicable for the strong interaction, strictly a U_L(n)xU_R(n)->U_V(n) spontaneous symmetry breaking is possible. The reason behind this is the existence of a discrete subset of axial symmetries, which connects various U_V(n) symmetric vacua of the theory. The results are in agreement with the Vafa-Witten theorem of QCD, illustrating that it remains valid, even without gauge fields, for an effective model of the strong interaction.
[ { "created": "Fri, 14 Dec 2012 09:06:39 GMT", "version": "v1" }, { "created": "Wed, 13 Mar 2013 19:00:39 GMT", "version": "v2" } ]
2015-06-12
[ [ "Fejos", "G.", "" ] ]
Chiral symmetry breaking patterns are investigated in the U_L(n)xU_R(n) meson model. It is shown that new classes of minima of the effective potential belonging to the center of the Lie algebra exist for arbitrary flavor number n. The true ground state of the system is searched nonperturbatively and although multiple local minima of the effective potential may exist, it is argued that in regions of the parameter space applicable for the strong interaction, strictly a U_L(n)xU_R(n)->U_V(n) spontaneous symmetry breaking is possible. The reason behind this is the existence of a discrete subset of axial symmetries, which connects various U_V(n) symmetric vacua of the theory. The results are in agreement with the Vafa-Witten theorem of QCD, illustrating that it remains valid, even without gauge fields, for an effective model of the strong interaction.
2305.07395
Axel Maas
Axel Maas
Experimental signatures of subtleties in the Brout-Englert-Higgs mechanism
6 pages, 3 figures, contribution to the 2023 Electroweak session of the 57th Rencontres de Moriond
null
null
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Subtle, but long-known, field-theoretical aspects require a more refined treatment of gauge theories involving a Brout-Englert-Higgs effect. This refinement can be done analytically using the Fr\"ohlich-Morchio-Strocchi mechanism. In the standard model, this leads to slight, but in principle detectable, quantitative changes in observables. This can have significant implications for current and future colliders, which are investigated for a few sample processes.
[ { "created": "Fri, 12 May 2023 11:42:56 GMT", "version": "v1" } ]
2023-05-15
[ [ "Maas", "Axel", "" ] ]
Subtle, but long-known, field-theoretical aspects require a more refined treatment of gauge theories involving a Brout-Englert-Higgs effect. This refinement can be done analytically using the Fr\"ohlich-Morchio-Strocchi mechanism. In the standard model, this leads to slight, but in principle detectable, quantitative changes in observables. This can have significant implications for current and future colliders, which are investigated for a few sample processes.
1202.1701
Majid Hashemi
Majid Hashemi
Charged Higgs Detection in the $\tau\nu$ Decay Mode at Future Linear Colliders
19 pages, 11 figures, 2 tables
Phys. Rev. D 86 (2012) 115002
10.1103/PhysRevD.86.115002
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Charged Higgs phenomenology and detection chance at future linear colliders through the production process $e^{-}e^{+} \ra H^{+}H^{-} \ra \tau^{+}\nu \tau \bar{\nu}$ is studied. Both charged Higgs bosons are considered to decay to $\tau\nu$ and the hadronic decay of $\tau$ leptons is analyzed taking into account spin and kinematics effects using a proper simulation of the $\tau$ lepton decay. It is shown that within the MSSM framework, with \tanb = 10, a wide range of charged Higgs masses would have detectable signal beyond the $5\sigma$ statistical significance at linear colliders with $\sqrt{s} = 500$ and 1000 GeV.
[ { "created": "Wed, 8 Feb 2012 14:14:56 GMT", "version": "v1" }, { "created": "Mon, 23 Apr 2012 09:01:43 GMT", "version": "v2" }, { "created": "Mon, 24 Sep 2012 09:47:21 GMT", "version": "v3" }, { "created": "Sun, 11 Jan 2015 09:47:01 GMT", "version": "v4" } ]
2015-01-13
[ [ "Hashemi", "Majid", "" ] ]
Charged Higgs phenomenology and detection chance at future linear colliders through the production process $e^{-}e^{+} \ra H^{+}H^{-} \ra \tau^{+}\nu \tau \bar{\nu}$ is studied. Both charged Higgs bosons are considered to decay to $\tau\nu$ and the hadronic decay of $\tau$ leptons is analyzed taking into account spin and kinematics effects using a proper simulation of the $\tau$ lepton decay. It is shown that within the MSSM framework, with \tanb = 10, a wide range of charged Higgs masses would have detectable signal beyond the $5\sigma$ statistical significance at linear colliders with $\sqrt{s} = 500$ and 1000 GeV.
1502.05509
Javier Virto
S\'ebastien Descotes-Genon, Javier Virto
Time dependence in $B\to V\ell\ell$ decays
39 pages, 3 figures. Typos corrected. Matches published version
JHEP 04 (2015) 045
10.1007/JHEP04(2015)045
LPT-Orsay/15-14, QFET-2015-06, SI-HEP-2015-05
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We discuss the theory and phenomenology of $B_{d,s}\to V(\to M_1M_2)\ell\ell$ decays in the presence of neutral-meson mixing. We derive expressions for the time-dependent angular distributions for decays into CP eigenstates, and identify the relevant observables that can be extracted from time-integrated and time-dependent analyses with or without tagging, with a focus on the difference between measurements at $B$-factories and hadronic machines. We construct two observables of interest, which we call $Q_8^-$ and $Q_9$, and which are theoretically clean at large recoil. We compute these two observables in the Standard Model, and show that they have good potential for New Physics searches by considering their sensitivity to benchmark New Physics scenarios consistent with current $b\to s\ell\ell$ data. These results apply to decays such as $B_d\to K^*(\to K_S\pi^0)\ell\ell$, $B_s\to \phi (\to K_SK_L)\ell\ell$ and $B_s\to \phi(\to K^+K^-)\ell\ell$.
[ { "created": "Thu, 19 Feb 2015 09:33:07 GMT", "version": "v1" }, { "created": "Fri, 10 Jul 2015 09:19:43 GMT", "version": "v2" } ]
2015-07-13
[ [ "Descotes-Genon", "Sébastien", "" ], [ "Virto", "Javier", "" ] ]
We discuss the theory and phenomenology of $B_{d,s}\to V(\to M_1M_2)\ell\ell$ decays in the presence of neutral-meson mixing. We derive expressions for the time-dependent angular distributions for decays into CP eigenstates, and identify the relevant observables that can be extracted from time-integrated and time-dependent analyses with or without tagging, with a focus on the difference between measurements at $B$-factories and hadronic machines. We construct two observables of interest, which we call $Q_8^-$ and $Q_9$, and which are theoretically clean at large recoil. We compute these two observables in the Standard Model, and show that they have good potential for New Physics searches by considering their sensitivity to benchmark New Physics scenarios consistent with current $b\to s\ell\ell$ data. These results apply to decays such as $B_d\to K^*(\to K_S\pi^0)\ell\ell$, $B_s\to \phi (\to K_SK_L)\ell\ell$ and $B_s\to \phi(\to K^+K^-)\ell\ell$.
hep-ph/9707512
Evan Keith
E. Keith, Ernest Ma, and D. P. Roy
Lower Bound on the Pseudoscalar Mass in the Minimal Supersymmetric Standard Model
11 pages including 2 figs, reference added
Phys.Rev.D56:5306-5309,1997
10.1103/PhysRevD.56.R5306
UCRHEP-T196, Fermilab Pub-97/292-T
hep-ph
null
In the Higgs sector of the Minimal Supersymmetric Standard Model, the mass of the pseudoscalar $A$ is an independent parameter together with $\tan \beta \equiv v_2/v_1$. If $m_A$ is small, then the process $e^+ e^- \to h + A$ is kinematically allowed and is suppressed only if $\tan \beta$ is small. On the other hand, the mass of the charged Higgs boson is now near $M_W$, and the decay $t \to b + h^+$ is enhanced if $\tan \beta$ is small. Since the former has not been observed, and the branching fraction of $t \to b + W$ cannot be too small (by comparing the experimentally derived $t \bar t$ cross section from the leptonic channels with the theoretical prediction), we can infer a phenomenological lower bound on $m_A$ of at least 60 GeV for all values of $\tan \beta$.
[ { "created": "Tue, 29 Jul 1997 22:36:22 GMT", "version": "v1" }, { "created": "Fri, 8 Aug 1997 00:23:19 GMT", "version": "v2" } ]
2009-12-30
[ [ "Keith", "E.", "" ], [ "Ma", "Ernest", "" ], [ "Roy", "D. P.", "" ] ]
In the Higgs sector of the Minimal Supersymmetric Standard Model, the mass of the pseudoscalar $A$ is an independent parameter together with $\tan \beta \equiv v_2/v_1$. If $m_A$ is small, then the process $e^+ e^- \to h + A$ is kinematically allowed and is suppressed only if $\tan \beta$ is small. On the other hand, the mass of the charged Higgs boson is now near $M_W$, and the decay $t \to b + h^+$ is enhanced if $\tan \beta$ is small. Since the former has not been observed, and the branching fraction of $t \to b + W$ cannot be too small (by comparing the experimentally derived $t \bar t$ cross section from the leptonic channels with the theoretical prediction), we can infer a phenomenological lower bound on $m_A$ of at least 60 GeV for all values of $\tan \beta$.
2210.09311
Evan Craft
Evan Craft, Kyle Lee, Bianka Me\c{c}aj, Ian Moult
Beautiful and Charming Energy Correlators
2 beautiful figures, 2 charming figures
null
null
MIT-CTP 5474
hep-ph hep-ex nucl-ex nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Understanding the detailed structure of energy flow within jets, a field known as jet substructure, plays a central role in searches for new physics, and precision studies of QCD. Many applications of jet substructure require an understanding of jets initiated by heavy quarks, whose description has lagged behind remarkable recent progress for massless jets. In this Letter, we initiate a study of correlation functions of energy flow operators on beauty and charm jets to illuminate the effects of the intrinsic mass of the elementary particles of QCD. We present a factorization theorem incorporating the mass of heavy quarks, and show that the heavy quark jet functions for energy correlators have a simple structure in perturbation theory. Our results achieve the very first full next-to-leading-logarithmic calculation of the heavy quark jet substructure observable at the LHC. Using this framework, we study the behavior of the correlators, and show that they exhibit a clear transition from a massless scaling regime, at precisely the scale of the heavy quark mass. This manifests the long-sought-after dead-cone effect and illustrates fundamental effects from the intrinsic mass of beauty and charm quarks in a perturbative regime, before they are confined inside hadrons. Our theoretical framework for studying energy correlators using heavy jets has many exciting applications for improving the description of mass effects in next generation parton shower event generators, probing the QGP, and studying heavy flavor fragmentation functions.
[ { "created": "Mon, 17 Oct 2022 18:00:00 GMT", "version": "v1" } ]
2022-10-19
[ [ "Craft", "Evan", "" ], [ "Lee", "Kyle", "" ], [ "Meçaj", "Bianka", "" ], [ "Moult", "Ian", "" ] ]
Understanding the detailed structure of energy flow within jets, a field known as jet substructure, plays a central role in searches for new physics, and precision studies of QCD. Many applications of jet substructure require an understanding of jets initiated by heavy quarks, whose description has lagged behind remarkable recent progress for massless jets. In this Letter, we initiate a study of correlation functions of energy flow operators on beauty and charm jets to illuminate the effects of the intrinsic mass of the elementary particles of QCD. We present a factorization theorem incorporating the mass of heavy quarks, and show that the heavy quark jet functions for energy correlators have a simple structure in perturbation theory. Our results achieve the very first full next-to-leading-logarithmic calculation of the heavy quark jet substructure observable at the LHC. Using this framework, we study the behavior of the correlators, and show that they exhibit a clear transition from a massless scaling regime, at precisely the scale of the heavy quark mass. This manifests the long-sought-after dead-cone effect and illustrates fundamental effects from the intrinsic mass of beauty and charm quarks in a perturbative regime, before they are confined inside hadrons. Our theoretical framework for studying energy correlators using heavy jets has many exciting applications for improving the description of mass effects in next generation parton shower event generators, probing the QGP, and studying heavy flavor fragmentation functions.
1409.0701
Francois Gelis
Thomas Epelbaum, Francois Gelis, Naoto Tanji, Bin Wu
Properties of the Boltzmann equation in the classical approximation
37 pages, 21 figures
Phys. Rev. D 90, 125032 (2014)
10.1103/PhysRevD.90.125032
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the Boltzmann equation with elastic point-like scalar interactions in two different versions of the the classical approximation. Although solving numerically the Boltzmann equation with the unapproximated collision term poses no problem, this allows one to study the effect of the ultraviolet cutoff in these approximations. This cutoff dependence in the classical approximations of the Boltzmann equation is closely related to the non-renormalizability of the classical statistical approximation of the underlying quantum field theory. The kinetic theory setup that we consider here allows one to study in a much simpler way the dependence on the ultraviolet cutoff, since one has also access to the non-approximated result for comparison.
[ { "created": "Tue, 2 Sep 2014 13:40:37 GMT", "version": "v1" } ]
2015-01-07
[ [ "Epelbaum", "Thomas", "" ], [ "Gelis", "Francois", "" ], [ "Tanji", "Naoto", "" ], [ "Wu", "Bin", "" ] ]
We study the Boltzmann equation with elastic point-like scalar interactions in two different versions of the the classical approximation. Although solving numerically the Boltzmann equation with the unapproximated collision term poses no problem, this allows one to study the effect of the ultraviolet cutoff in these approximations. This cutoff dependence in the classical approximations of the Boltzmann equation is closely related to the non-renormalizability of the classical statistical approximation of the underlying quantum field theory. The kinetic theory setup that we consider here allows one to study in a much simpler way the dependence on the ultraviolet cutoff, since one has also access to the non-approximated result for comparison.
1807.00912
Li-Sheng Geng
Ming-Zhu Liu, Yang Xiao, and Li-Sheng Geng
Magnetic moments of the spin-1/2 doubly charmed baryons in covariant baryon chiral perturbation theory
6 pages, 4 figures
Phys. Rev. D 98, 014040 (2018)
10.1103/PhysRevD.98.014040
null
hep-ph hep-lat
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Inspired by the recent discovery of the $\Xi_{cc}^{++}$ by the LHCb Collaboration, we study the magnetic moments of the spin-1/2 doubly charmed baryons up to the next-to-leading order in covariant baryon chiral perturbation theory with the extended-on-mass-shell renormalization scheme. There are three low energy constants at this order, $a_1$, $a_2$ and $g_a$. The latest lattice QCD simulations allow us to fix a combination of $a_1$ and $a_2$, while the axial-vector coupling $g_a$ can be determined in three different ways, either by fitting to the lattice QCD data, or by the quark model, or by the heavy antiquark diquark symmetry. The magnetic moments of the spin-1/2 doubly charmed baryons $\Xi^d_{cc}$ and $\Xi^s_{cc}$ can then be predicted. We compare our results with those obtained in the heavy baryon chiral perturbation theory and other approaches, and point out some inconsistencies between the lattice QCD simulations and the quark model.
[ { "created": "Mon, 2 Jul 2018 22:06:15 GMT", "version": "v1" }, { "created": "Wed, 8 Aug 2018 15:52:53 GMT", "version": "v2" } ]
2018-08-09
[ [ "Liu", "Ming-Zhu", "" ], [ "Xiao", "Yang", "" ], [ "Geng", "Li-Sheng", "" ] ]
Inspired by the recent discovery of the $\Xi_{cc}^{++}$ by the LHCb Collaboration, we study the magnetic moments of the spin-1/2 doubly charmed baryons up to the next-to-leading order in covariant baryon chiral perturbation theory with the extended-on-mass-shell renormalization scheme. There are three low energy constants at this order, $a_1$, $a_2$ and $g_a$. The latest lattice QCD simulations allow us to fix a combination of $a_1$ and $a_2$, while the axial-vector coupling $g_a$ can be determined in three different ways, either by fitting to the lattice QCD data, or by the quark model, or by the heavy antiquark diquark symmetry. The magnetic moments of the spin-1/2 doubly charmed baryons $\Xi^d_{cc}$ and $\Xi^s_{cc}$ can then be predicted. We compare our results with those obtained in the heavy baryon chiral perturbation theory and other approaches, and point out some inconsistencies between the lattice QCD simulations and the quark model.
1705.06252
Christoph Meyer
Christoph Meyer
Algorithmic transformation of multi-loop master integrals to a canonical basis with CANONICA
CANONICA can be obtained with git clone https://github.com/christophmeyer/CANONICA.git or at https://github.com/christophmeyer/CANONICA/archive/v1.0.tar.gz
null
10.1016/j.cpc.2017.09.014
HU-EP-17/10
hep-ph
http://creativecommons.org/licenses/by/4.0/
The integration of differential equations of Feynman integrals can be greatly facilitated by using a canonical basis. This paper presents the Mathematica package CANONICA, which implements a recently developed algorithm to automatize the transformation to a canonical basis. This represents the first publicly available implementation suitable for differential equations depending on multiple scales. In addition to the presentation of the package, this paper extends the description of some aspects of the algorithm, including a proof of the uniqueness of canonical forms up to constant transformations.
[ { "created": "Wed, 17 May 2017 16:35:45 GMT", "version": "v1" }, { "created": "Wed, 29 Nov 2017 13:54:59 GMT", "version": "v2" } ]
2017-11-30
[ [ "Meyer", "Christoph", "" ] ]
The integration of differential equations of Feynman integrals can be greatly facilitated by using a canonical basis. This paper presents the Mathematica package CANONICA, which implements a recently developed algorithm to automatize the transformation to a canonical basis. This represents the first publicly available implementation suitable for differential equations depending on multiple scales. In addition to the presentation of the package, this paper extends the description of some aspects of the algorithm, including a proof of the uniqueness of canonical forms up to constant transformations.
2407.19797
Zhuoni Qian
Nuoyu Dong, Hongsheng Hou, Zhuoni Qian, Bowen Wang, Qingjun Xu
Probing Charm Yukawa through $ch$ Associated Production at the Hadron Collider
19 pages, 6 figures, 4 tables
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
At present, the study of the charm-quark Yukawa coupling at the Large Hadron Collider mainly restricts the coupling constant $y_c$ through the Higgs decay channels. Such signal suffers from overwhelming QCD background, and derives most sensitivity from the $Vh$ associated production channel. In addition, sensitivity to a possible CP complex term of $y_c$ is lost. We study the $ch$ associated production channel at the HL-LHC and FCC to probe the charm Yukawa coupling. By making use of the interference contribution among channels, and machine learning techniques to separate the different contributions, sensitivity on possible deviation from a standard model charm Yukawa coupling is derived. Under the $\kappa$ framework, a 1$\sigma$ projected bounds of $\kappa_c < 5.62$ (HL-LHC) and $-1.52 < \kappa_c < 1.62$ (FCC) are achieved. When further allowing for CP-structure for the charm Yukawa, and comparing with other complementary hadron collider signals, we reach projected bounds on the CP-odd and CP-even components of the charm Yukawa of $-2.46 < \tilde{\kappa_c} < 2.46$, $ 0.23 < \kappa_c < 1.74$ at the HL-LHC and $-1.05 < \tilde{\kappa_c} < 1.05$, $ 0.57 < \kappa_c < 1.28$ at the FCC.
[ { "created": "Mon, 29 Jul 2024 08:43:16 GMT", "version": "v1" } ]
2024-07-30
[ [ "Dong", "Nuoyu", "" ], [ "Hou", "Hongsheng", "" ], [ "Qian", "Zhuoni", "" ], [ "Wang", "Bowen", "" ], [ "Xu", "Qingjun", "" ] ]
At present, the study of the charm-quark Yukawa coupling at the Large Hadron Collider mainly restricts the coupling constant $y_c$ through the Higgs decay channels. Such signal suffers from overwhelming QCD background, and derives most sensitivity from the $Vh$ associated production channel. In addition, sensitivity to a possible CP complex term of $y_c$ is lost. We study the $ch$ associated production channel at the HL-LHC and FCC to probe the charm Yukawa coupling. By making use of the interference contribution among channels, and machine learning techniques to separate the different contributions, sensitivity on possible deviation from a standard model charm Yukawa coupling is derived. Under the $\kappa$ framework, a 1$\sigma$ projected bounds of $\kappa_c < 5.62$ (HL-LHC) and $-1.52 < \kappa_c < 1.62$ (FCC) are achieved. When further allowing for CP-structure for the charm Yukawa, and comparing with other complementary hadron collider signals, we reach projected bounds on the CP-odd and CP-even components of the charm Yukawa of $-2.46 < \tilde{\kappa_c} < 2.46$, $ 0.23 < \kappa_c < 1.74$ at the HL-LHC and $-1.05 < \tilde{\kappa_c} < 1.05$, $ 0.57 < \kappa_c < 1.28$ at the FCC.
1512.00108
Abhishek Mohapatra
Eric Braaten, Abhishek Mohapatra and Hong Zhang
Dense Axion Stars
5 pages, 2 figures, Added calculations of unstable branch of axion stars. Added discussion of possible ways to detect dense axion stars. Removed EFT calculations that were not essential for this paper
Phys. Rev. Lett. 117, 121801 (2016)
10.1103/PhysRevLett.117.121801
null
hep-ph astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
If the dark matter particles are axions, gravity can cause them to coalesce into axion stars, which are stable gravitationally bound systems of axions. In the previously known solutions for axion stars, gravity and the attractive force between pairs of axions are balanced by the kinetic pressure. The mass of these dilute axion stars cannot exceed a critical mass, which is about $10^{-14} M_\odot$ if the axion mass is $10^{-4}$~eV. We study axion stars using a simple approximation to the effective potential of the nonrelativistic effective field theory for axions. We find a new branch of dense axion stars in which gravity is balanced by the mean-field pressure of the axion Bose-Einstein condensate. The mass on this branch ranges from about $10^{-20} M_\odot$ to about $M_\odot$. If a dilute axion star with the critical mass accretes additional axions and collapses, it could produce a bosenova, leaving a dense axion star as the remnant.
[ { "created": "Tue, 1 Dec 2015 00:53:18 GMT", "version": "v1" }, { "created": "Fri, 16 Sep 2016 20:36:55 GMT", "version": "v2" } ]
2016-09-20
[ [ "Braaten", "Eric", "" ], [ "Mohapatra", "Abhishek", "" ], [ "Zhang", "Hong", "" ] ]
If the dark matter particles are axions, gravity can cause them to coalesce into axion stars, which are stable gravitationally bound systems of axions. In the previously known solutions for axion stars, gravity and the attractive force between pairs of axions are balanced by the kinetic pressure. The mass of these dilute axion stars cannot exceed a critical mass, which is about $10^{-14} M_\odot$ if the axion mass is $10^{-4}$~eV. We study axion stars using a simple approximation to the effective potential of the nonrelativistic effective field theory for axions. We find a new branch of dense axion stars in which gravity is balanced by the mean-field pressure of the axion Bose-Einstein condensate. The mass on this branch ranges from about $10^{-20} M_\odot$ to about $M_\odot$. If a dilute axion star with the critical mass accretes additional axions and collapses, it could produce a bosenova, leaving a dense axion star as the remnant.
hep-ph/0312343
Oleg Pavlovsky
Oleg V. Pavlovsky
Soliton solutions of Chiral Born-Infeld Theory and baryons
4 pages, LaTeX; talk presented at the 12th International Seminar on High Energy Physics Quarks'2002, Novgorod, Russia, June, 2002; to appear in the proceedings of the conference
null
null
null
hep-ph
null
Finite-energy topological spherically symmetrical solutions of Chiral Born-Infeld Theory are studied. Properties of these solution are obtained, and a possible physical interpretation is also given. We compute static properties of baryons (mass,main radius, magnetic main radius, axial coupling constant) whose solutions can be interpreted as the baryons of QCD.
[ { "created": "Wed, 24 Dec 2003 16:55:21 GMT", "version": "v1" } ]
2007-05-23
[ [ "Pavlovsky", "Oleg V.", "" ] ]
Finite-energy topological spherically symmetrical solutions of Chiral Born-Infeld Theory are studied. Properties of these solution are obtained, and a possible physical interpretation is also given. We compute static properties of baryons (mass,main radius, magnetic main radius, axial coupling constant) whose solutions can be interpreted as the baryons of QCD.
2003.11856
Ilkka Helenius
Kari J. Eskola, Ilkka Helenius, Mikko Kuha and Hannu Paukkunen
Shadowing in inelastic nucleon-nucleon cross section?
6 pages, 4 figures
Phys. Rev. Lett. 125, 212301 (2020)
10.1103/PhysRevLett.125.212301
null
hep-ph nucl-th
http://creativecommons.org/licenses/by/4.0/
Experimental results of inclusive hard-process cross sections in heavy-ion collisions conventionally lean on a normalization computed from Glauber models where the inelastic nucleon-nucleon cross section $\sigma_{\rm nn}^{\rm inel}$ -- a crucial input parameter -- is simply taken from proton-proton measurements. In this letter, using the computed electro-weak boson production cross sections in lead-lead collisions as a benchmark, we determine $\sigma_{\rm nn}^{\rm inel}$ from the recent ATLAS data. We find a significantly suppressed $\sigma_{\rm nn}^{\rm inel}$ relative to what is usually assumed, show the consequences for the centrality dependence of the cross sections, and address the phenomenon in an eikonal minijet model with nuclear shadowing.
[ { "created": "Thu, 26 Mar 2020 12:17:18 GMT", "version": "v1" } ]
2020-11-25
[ [ "Eskola", "Kari J.", "" ], [ "Helenius", "Ilkka", "" ], [ "Kuha", "Mikko", "" ], [ "Paukkunen", "Hannu", "" ] ]
Experimental results of inclusive hard-process cross sections in heavy-ion collisions conventionally lean on a normalization computed from Glauber models where the inelastic nucleon-nucleon cross section $\sigma_{\rm nn}^{\rm inel}$ -- a crucial input parameter -- is simply taken from proton-proton measurements. In this letter, using the computed electro-weak boson production cross sections in lead-lead collisions as a benchmark, we determine $\sigma_{\rm nn}^{\rm inel}$ from the recent ATLAS data. We find a significantly suppressed $\sigma_{\rm nn}^{\rm inel}$ relative to what is usually assumed, show the consequences for the centrality dependence of the cross sections, and address the phenomenon in an eikonal minijet model with nuclear shadowing.
1001.2746
Jacobo Ruiz de Elvira
J. Ruiz de Elvira, J.R. Pelaez, M.R. Pennington, D.J. Wilson
Structure of the lightest scalar meson from the 1/Nc expansion of Unitarized Chiral Perturbation Theory and Regge Theory
To appear in the Proceedings of the Hadron09 International Conference. 29th Nov-4th Dec. 2009. Tallahassee, FL, USA. 5 pages
null
10.1063/1.3483373
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
One-loop unitarized Chiral Perturbation Theory (UChPT) calculations, suggest a different Nc behaviour for the sigma or f_0(600) and rho(770) mesons: while the rho meson becomes narrower with Nc, as is expected for a q-qbar meson, the sigma becomes broader, and its contribution to the total cross section is less and less important. On the other hand, local duality requires a cancellation between the sigma and rho amplitudes, but if there is a different Nc behaviour for them, there is a possible contradiction between the Inverse Amplitude Method (IAM) and local duality for large Nc. However, next to next to leading order UChPT calculations suggested a subdominant q-qbar component for the sigma with a mass around 1.2 GeV. In this work, we show that this subdominant q-qbar component is indeed needed to ensure local duality.
[ { "created": "Fri, 15 Jan 2010 17:59:10 GMT", "version": "v1" } ]
2015-05-18
[ [ "de Elvira", "J. Ruiz", "" ], [ "Pelaez", "J. R.", "" ], [ "Pennington", "M. R.", "" ], [ "Wilson", "D. J.", "" ] ]
One-loop unitarized Chiral Perturbation Theory (UChPT) calculations, suggest a different Nc behaviour for the sigma or f_0(600) and rho(770) mesons: while the rho meson becomes narrower with Nc, as is expected for a q-qbar meson, the sigma becomes broader, and its contribution to the total cross section is less and less important. On the other hand, local duality requires a cancellation between the sigma and rho amplitudes, but if there is a different Nc behaviour for them, there is a possible contradiction between the Inverse Amplitude Method (IAM) and local duality for large Nc. However, next to next to leading order UChPT calculations suggested a subdominant q-qbar component for the sigma with a mass around 1.2 GeV. In this work, we show that this subdominant q-qbar component is indeed needed to ensure local duality.
hep-ph/0606178
Mei Huang
Ioannis Giannakis, Defu Hou, Mei Huang, Hai-cang Ren
Higgs instability in gapless superfluidity/superconductivity
4 pages, 2 figure, one figure added
Phys.Rev. D75 (2007) 011501
10.1103/PhysRevD.75.011501
RU06-4-B, TKYNT-06-7
hep-ph astro-ph cond-mat.supr-con nucl-th
null
In this letter we explore the Higgs instability in the gapless superfluid/superconducting phase. This is in addition to the (chromo)magnetic instability that is related to the fluctuations of the Nambu-Goldstone bosonic fields. While the latter may induce a single-plane-wave LOFF state, the Higgs instability favors spatial inhomogeneity and cannot be removed without a long range force. In the case of the g2SC state the Higgs instability can only be partially removed by the electric Coulomb energy. But this does not exclude the possibility that it can be completely removed in other exotic states such as the gCFL state.
[ { "created": "Fri, 16 Jun 2006 10:43:22 GMT", "version": "v1" }, { "created": "Tue, 18 Jul 2006 08:45:09 GMT", "version": "v2" } ]
2009-11-11
[ [ "Giannakis", "Ioannis", "" ], [ "Hou", "Defu", "" ], [ "Huang", "Mei", "" ], [ "Ren", "Hai-cang", "" ] ]
In this letter we explore the Higgs instability in the gapless superfluid/superconducting phase. This is in addition to the (chromo)magnetic instability that is related to the fluctuations of the Nambu-Goldstone bosonic fields. While the latter may induce a single-plane-wave LOFF state, the Higgs instability favors spatial inhomogeneity and cannot be removed without a long range force. In the case of the g2SC state the Higgs instability can only be partially removed by the electric Coulomb energy. But this does not exclude the possibility that it can be completely removed in other exotic states such as the gCFL state.
1512.06128
Simon Knapen
Timothy Cohen, Nathaniel Craig, Simon Knapen
Gauge Mediated Mini-Split
16 pages, 1 figure. Journal version, references added
null
10.1007/JHEP03(2016)103
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose a simple model of split supersymmetry from gauge mediation. This model features gauginos that are parametrically a loop factor lighter than scalars, accommodates a Higgs boson mass of 125 GeV, and incorporates a simple solution to the $\mu-b_\mu$ problem. The gaugino mass suppression can be understood as resulting from collective symmetry breaking. Imposing collider bounds on $\mu$ and requiring viable electroweak symmetry breaking implies small $a$-terms and small $\tan \beta$ -- the stop mass ranges from $10^5$ to $10^8 \mbox{ GeV}$. In contrast with models with anomaly + gravity mediation (which also predict a one-loop loop suppression for gaugino masses), our gauge mediated scenario predicts aligned squark masses and a gravitino LSP. Gluinos, electroweakinos and Higgsinos can be accessible at the LHC and/or future colliders for a wide region of the allowed parameter space.
[ { "created": "Fri, 18 Dec 2015 21:00:01 GMT", "version": "v1" }, { "created": "Mon, 28 Mar 2016 17:36:59 GMT", "version": "v2" } ]
2016-04-20
[ [ "Cohen", "Timothy", "" ], [ "Craig", "Nathaniel", "" ], [ "Knapen", "Simon", "" ] ]
We propose a simple model of split supersymmetry from gauge mediation. This model features gauginos that are parametrically a loop factor lighter than scalars, accommodates a Higgs boson mass of 125 GeV, and incorporates a simple solution to the $\mu-b_\mu$ problem. The gaugino mass suppression can be understood as resulting from collective symmetry breaking. Imposing collider bounds on $\mu$ and requiring viable electroweak symmetry breaking implies small $a$-terms and small $\tan \beta$ -- the stop mass ranges from $10^5$ to $10^8 \mbox{ GeV}$. In contrast with models with anomaly + gravity mediation (which also predict a one-loop loop suppression for gaugino masses), our gauge mediated scenario predicts aligned squark masses and a gravitino LSP. Gluinos, electroweakinos and Higgsinos can be accessible at the LHC and/or future colliders for a wide region of the allowed parameter space.
2401.12893
Dmitry Gorbunov
Dmitry Gorbunov, Dmitry Kalashnikov
NICA prospects in searches for light exotics from hidden sectors: the cases of hidden photons and axion-like particles
12 pages, 7 figures; replaced with the journal version
null
null
INR-TH-2024-001
hep-ph
http://creativecommons.org/licenses/by/4.0/
We present first estimates of NICA sensitivity to Standard Model extensions with light hypothetical particles singlet under the known gauge transformations. Our analysis reveals that NICA can explore new regions in the parameter spaces of models with a hidden vector and models with an axion-like particle of masses about 30-500\,MeV. Some of these regions seem unreachable by other ongoing and approved future projects. NICA has good prospects in discovery ($5\sigma$) of the new physics after 1 year of data taking.
[ { "created": "Tue, 23 Jan 2024 16:34:46 GMT", "version": "v1" }, { "created": "Sat, 6 Apr 2024 09:39:31 GMT", "version": "v2" } ]
2024-04-09
[ [ "Gorbunov", "Dmitry", "" ], [ "Kalashnikov", "Dmitry", "" ] ]
We present first estimates of NICA sensitivity to Standard Model extensions with light hypothetical particles singlet under the known gauge transformations. Our analysis reveals that NICA can explore new regions in the parameter spaces of models with a hidden vector and models with an axion-like particle of masses about 30-500\,MeV. Some of these regions seem unreachable by other ongoing and approved future projects. NICA has good prospects in discovery ($5\sigma$) of the new physics after 1 year of data taking.
hep-ph/0204249
Adam Szczepaniak
Adam P. Szczepaniak and Pawel Krupinski
Spontaneous chiral symmetry breaking in the linked cluster expansion
13 pages, 9 figures
Phys.Rev. D66 (2002) 096006
10.1103/PhysRevD.66.096006
null
hep-ph
null
We investigate dynamical chiral symmetry breaking in the Coulomb gauge Hamiltonian QCD. Within the framework of the linked cluster expansion we extend the BCS ansatz for the vacuum and include correlation beyond the quark-antiquark paring. In particular we study the effects of the three-body correlations involving quark-antiquark and transverse gluons. The high momentum behavior of the resulting gap equation is discussed and numerical computation of the chiral symmetry breaking is presented.
[ { "created": "Sun, 21 Apr 2002 19:02:00 GMT", "version": "v1" } ]
2009-11-07
[ [ "Szczepaniak", "Adam P.", "" ], [ "Krupinski", "Pawel", "" ] ]
We investigate dynamical chiral symmetry breaking in the Coulomb gauge Hamiltonian QCD. Within the framework of the linked cluster expansion we extend the BCS ansatz for the vacuum and include correlation beyond the quark-antiquark paring. In particular we study the effects of the three-body correlations involving quark-antiquark and transverse gluons. The high momentum behavior of the resulting gap equation is discussed and numerical computation of the chiral symmetry breaking is presented.
2407.02195
Bakar Chargeishvili
Bakar Chargeishvili, Giuseppe Bevilacqua, Adam Kardos, Sven-Olaf Moch, Zolt\'an Tr\'ocs\'anyi
Analysis of $(n+1)$ and $n$-parton contributions for computing QCD jet cross sections in the local analytic subtraction scheme
10 pages, 4 figures, contribution to the proceedings of Loops and Legs in Quantum Field Theory (LL2024), Wittenberg, Germany
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We analyze and implement the Local Analytic Sector Subtraction (LASS) scheme for handling infrared singularities in next-to-next-to-leading order (NNLO) calculations in perturbative QCD. We examine the key aspects of the scheme including sector function construction, singular limit parametrization, subtraction counterterm derivation, and integration techniques. As a proof-of-concept, we numerically implement LASS for the process $e^+e^- \rightarrow 3$ jets. In this study we examine the limiting behavior of subtraction terms for real-virtual contribution and explicitly demonstrate the pole cancellation of the double-virtual contribution. Differential cross sections are computed for several event shape observables, showing the stability and efficiency of LASS scheme. This work lays the foundation for developing an automated tool for NNLO QCD calculations using this promising scheme.
[ { "created": "Tue, 2 Jul 2024 11:52:01 GMT", "version": "v1" } ]
2024-07-03
[ [ "Chargeishvili", "Bakar", "" ], [ "Bevilacqua", "Giuseppe", "" ], [ "Kardos", "Adam", "" ], [ "Moch", "Sven-Olaf", "" ], [ "Trócsányi", "Zoltán", "" ] ]
We analyze and implement the Local Analytic Sector Subtraction (LASS) scheme for handling infrared singularities in next-to-next-to-leading order (NNLO) calculations in perturbative QCD. We examine the key aspects of the scheme including sector function construction, singular limit parametrization, subtraction counterterm derivation, and integration techniques. As a proof-of-concept, we numerically implement LASS for the process $e^+e^- \rightarrow 3$ jets. In this study we examine the limiting behavior of subtraction terms for real-virtual contribution and explicitly demonstrate the pole cancellation of the double-virtual contribution. Differential cross sections are computed for several event shape observables, showing the stability and efficiency of LASS scheme. This work lays the foundation for developing an automated tool for NNLO QCD calculations using this promising scheme.
hep-ph/9209221
Ernest Ma
Ernest Ma
Possible Finiteness of the Higgs-Boson Mass Renormalization
9 pages (2 figures not included)
Phys.Rev. D47 (1993) 2143-2146
10.1103/PhysRevD.47.2143
UCRHEP-T100 (Sep 1992) revised
hep-ph
null
It is shown by explicit calculation that the one-loop mass renormalization of the Higgs boson in the standard model is gauge-independent. It could even be rendered finite if the following mass relationships were satisfied: $m_t^2 \simeq m_H^2 = (2 M_W^2 + M_Z^2)/3$. Numerically, this would imply $m_t \simeq 84~GeV$ which is below the current experimental lower bound of 91 GeV, but since higher-order corrections are yet to be calculated, the above hypothesis could still have a chance of being realized.
[ { "created": "Mon, 7 Sep 1992 18:01:17 GMT", "version": "v1" }, { "created": "Thu, 10 Sep 1992 19:25:53 GMT", "version": "v2" } ]
2009-10-22
[ [ "Ma", "Ernest", "" ] ]
It is shown by explicit calculation that the one-loop mass renormalization of the Higgs boson in the standard model is gauge-independent. It could even be rendered finite if the following mass relationships were satisfied: $m_t^2 \simeq m_H^2 = (2 M_W^2 + M_Z^2)/3$. Numerically, this would imply $m_t \simeq 84~GeV$ which is below the current experimental lower bound of 91 GeV, but since higher-order corrections are yet to be calculated, the above hypothesis could still have a chance of being realized.
1210.0812
Kirill Melnikov
Jorge Mondejar and Kirill Melnikov
The VVA correlator at three loops in perturbative QCD
10 pages
null
10.1016/j.physletb.2012.12.009
TTP12-039
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It is known that the correlator of one axial and two vector currents, that receives leading contributions through one-loop fermion triangle diagrams, is not modified by QCD radiative corrections at two loops. It was suggested that this non-renormalization of the VVA correlator persists in higher orders in perturbative QCD as well. To check this assertion, we compute the three-loop QCD corrections to the VAA-correlator u sing the technique of asymptotic expansions. We find that these corrections do not vanish and that they are proportional to the QCD beta-function.
[ { "created": "Tue, 2 Oct 2012 15:47:17 GMT", "version": "v1" } ]
2015-06-11
[ [ "Mondejar", "Jorge", "" ], [ "Melnikov", "Kirill", "" ] ]
It is known that the correlator of one axial and two vector currents, that receives leading contributions through one-loop fermion triangle diagrams, is not modified by QCD radiative corrections at two loops. It was suggested that this non-renormalization of the VVA correlator persists in higher orders in perturbative QCD as well. To check this assertion, we compute the three-loop QCD corrections to the VAA-correlator u sing the technique of asymptotic expansions. We find that these corrections do not vanish and that they are proportional to the QCD beta-function.
hep-ph/0402063
Philip G. Ratcliffe
Philip G. Ratcliffe
Hyperon Beta Decay and the CKM Matrix
10 Pages, LaTeX2e, 1 EPS figure + 2 FeynFM figures. Invited talk at the Advanced Studies Institute, Symmetries and SPIN (SPIN-Praha-2003), Prague, July 12-19, 2003. Uses cjpsuppl.cls class file and other included style files
Czech.J.Phys.54:B11-B20,2004
null
null
hep-ph
null
I shall present a pedagogical discussion of hyperon semileptonic decays, covering some of the historical background, the basics notions of hyperon semileptonic decays, deeply inelastic scattering and the CKM matrix, and the description of SU(2) and SU(3) breaking. I shall also present a prediction for a process under current experimental study.
[ { "created": "Fri, 6 Feb 2004 02:08:48 GMT", "version": "v1" } ]
2010-11-23
[ [ "Ratcliffe", "Philip G.", "" ] ]
I shall present a pedagogical discussion of hyperon semileptonic decays, covering some of the historical background, the basics notions of hyperon semileptonic decays, deeply inelastic scattering and the CKM matrix, and the description of SU(2) and SU(3) breaking. I shall also present a prediction for a process under current experimental study.
0903.3241
Ilmo Sung
Alexander Mitov, George Sterman, Ilmo Sung
The Massive Soft Anomalous Dimension Matrix at Two Loops
7 pages, 3 figures, revtex
Phys.Rev.D79:094015,2009
10.1103/PhysRevD.79.094015
YITP-SB-09-06
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study two-loop anomalous dimension matrices in QCD and related gauge theories for products of Wilson lines coupled at a point. We verify by an analysis in Euclidean space that the contributions to these matrices from diagrams that link three massive Wilson lines do not vanish in general. We show, however, that for two-to-two processes the two-loop anomalous dimension matrix is diagonal in the same color-exchange basis as the one-loop matrix for arbitrary masses at absolute threshold and for scattering at ninety degrees in the center of mass. This result is important for applications of threshold resummation in heavy quark production.
[ { "created": "Thu, 19 Mar 2009 15:25:32 GMT", "version": "v1" }, { "created": "Fri, 20 Mar 2009 02:54:06 GMT", "version": "v2" } ]
2009-06-19
[ [ "Mitov", "Alexander", "" ], [ "Sterman", "George", "" ], [ "Sung", "Ilmo", "" ] ]
We study two-loop anomalous dimension matrices in QCD and related gauge theories for products of Wilson lines coupled at a point. We verify by an analysis in Euclidean space that the contributions to these matrices from diagrams that link three massive Wilson lines do not vanish in general. We show, however, that for two-to-two processes the two-loop anomalous dimension matrix is diagonal in the same color-exchange basis as the one-loop matrix for arbitrary masses at absolute threshold and for scattering at ninety degrees in the center of mass. This result is important for applications of threshold resummation in heavy quark production.
hep-ph/9601299
Jan Willem Bos
J.W. Bos, D. Chang, S.C. Lee, Y.C. Lin, H.H. Shih
Hyperon weak radiative decays in chiral perturbation theory
8 pages of REVTeX and using macro-package "feynman.tex" (available at http://xxx.lanl.gov/ftp/hep-ph/papers/macros) for the 2 figures
Phys.Rev. D54 (1996) 3321-3328
10.1103/PhysRevD.54.3321
null
hep-ph
null
We investigate the leading-order amplitudes for weak radiative decays of hyperons in chiral perturbation theory. We consistently include contributions from the next-to-leading order weak-interaction Lagrangian. It is shown that due to these terms Hara's theorem is violated. The data for the decays of charged hyperons can be easily accounted for. However, at this order in the chiral expansion, the four amplitudes for the decays of neutral hyperons satisfy relations which are in disagreement with the data. The asymmetry parameters for all the decays can not be accounted for without higher-order terms. We shortly comment on the effect of the 27-plet part of the weak interaction.
[ { "created": "Fri, 19 Jan 1996 12:57:43 GMT", "version": "v1" } ]
2009-10-28
[ [ "Bos", "J. W.", "" ], [ "Chang", "D.", "" ], [ "Lee", "S. C.", "" ], [ "Lin", "Y. C.", "" ], [ "Shih", "H. H.", "" ] ]
We investigate the leading-order amplitudes for weak radiative decays of hyperons in chiral perturbation theory. We consistently include contributions from the next-to-leading order weak-interaction Lagrangian. It is shown that due to these terms Hara's theorem is violated. The data for the decays of charged hyperons can be easily accounted for. However, at this order in the chiral expansion, the four amplitudes for the decays of neutral hyperons satisfy relations which are in disagreement with the data. The asymmetry parameters for all the decays can not be accounted for without higher-order terms. We shortly comment on the effect of the 27-plet part of the weak interaction.
hep-ph/0702207
Philip Amanik
Philip S. Amanik and Gail C. McLaughlin
Manipulating a Neutrino Spectrum to Maximize the Physics Potential from a Low Energy Beta Beam
18 pages, 10 figures
Phys.Rev.C75:065502,2007
10.1103/PhysRevC.75.065502
null
hep-ph nucl-th
null
Proposed low energy beta beam facilities would be capable of producing intense beams of neutrinos (anti-neutrinos) with well defined spectra. We present analytic expressions and numerical results which accurately show how the total neutrino flux reaching the detector depends on the geometry of the source and the detector. Several authors have proposed measurements which require using different flux shapes. We show that detectors of different sizes and shapes will receive neutrino fluxes with different spectral shapes, and that the spectral shape will also be different in different regions of the same detector. Our findings also show that for certain measurements systematic uncertainties and run time can be reduced.
[ { "created": "Tue, 20 Feb 2007 19:18:56 GMT", "version": "v1" }, { "created": "Mon, 18 Jun 2007 21:04:31 GMT", "version": "v2" } ]
2008-11-26
[ [ "Amanik", "Philip S.", "" ], [ "McLaughlin", "Gail C.", "" ] ]
Proposed low energy beta beam facilities would be capable of producing intense beams of neutrinos (anti-neutrinos) with well defined spectra. We present analytic expressions and numerical results which accurately show how the total neutrino flux reaching the detector depends on the geometry of the source and the detector. Several authors have proposed measurements which require using different flux shapes. We show that detectors of different sizes and shapes will receive neutrino fluxes with different spectral shapes, and that the spectral shape will also be different in different regions of the same detector. Our findings also show that for certain measurements systematic uncertainties and run time can be reduced.
1310.3509
Joseph Bramante
Joseph Bramante, Keita Fukushima, Jason Kumar, Elan Stopnitzky
Bounds on self-interacting fermion dark matter from observations of old neutron stars
35 pages, 8 figures, corrected typos
Phys. Rev. D 89, 015010 (2014)
10.1103/PhysRevD.89.015010
null
hep-ph astro-ph.CO astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The existence of old neutron stars deeply constrains self-interacting fermion dark matter, which can form star-killing black holes. We quantify this constraint on dark matter-nucleon scattering, considering collapse scenarios that broaden bounds over intermediate masses. We then find the self- and co-annihilation rates necessary to lift these dark matter-nucleon scattering bounds. For Yukawa-coupled dark matter that fits dwarf galaxy halo profiles with a coupling $\alpha = 10^{-1}-10^{-4}$, a scalar mediator mass $m_\phi = 1-500$ MeV, and DM mass $m_X = 0.1-10^7$ GeV, we show that fermion dark matter is unconstrained if it self-annihilates at a rate greater than $10^{-40} ~ \rm{cm^3/s}$ or co-annihilates with baryons at a rate greater than $10^{-50} ~ \rm{cm^3/s}$.
[ { "created": "Sun, 13 Oct 2013 20:00:11 GMT", "version": "v1" }, { "created": "Tue, 28 Jan 2014 02:19:42 GMT", "version": "v2" }, { "created": "Wed, 28 May 2014 20:03:09 GMT", "version": "v3" } ]
2014-05-30
[ [ "Bramante", "Joseph", "" ], [ "Fukushima", "Keita", "" ], [ "Kumar", "Jason", "" ], [ "Stopnitzky", "Elan", "" ] ]
The existence of old neutron stars deeply constrains self-interacting fermion dark matter, which can form star-killing black holes. We quantify this constraint on dark matter-nucleon scattering, considering collapse scenarios that broaden bounds over intermediate masses. We then find the self- and co-annihilation rates necessary to lift these dark matter-nucleon scattering bounds. For Yukawa-coupled dark matter that fits dwarf galaxy halo profiles with a coupling $\alpha = 10^{-1}-10^{-4}$, a scalar mediator mass $m_\phi = 1-500$ MeV, and DM mass $m_X = 0.1-10^7$ GeV, we show that fermion dark matter is unconstrained if it self-annihilates at a rate greater than $10^{-40} ~ \rm{cm^3/s}$ or co-annihilates with baryons at a rate greater than $10^{-50} ~ \rm{cm^3/s}$.
1012.1132
Irinel Caprini
Irinel Caprini and Jan Fischer
New perturbation expansions in quantum chromodynamics and the determination of $\alpha_s$
null
Rom.J.Phys.55:527-537,2010
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider a new class of perturbation expansions, which incorporate in a systematic way the available information about the divergent character of the perturbation series in QCD. The new expansion functions, which replace the powers of the coupling, are defined by the analytic continuation in the Borel plane, achieved through an optimal conformal mapping. We consider several possibilities of implementing the known behaviour of the Borel transform near the leading singularities in the complex plane and using the corresponding expansions. These expansions have the same asymptotic convergence rate, but differ at low orders. We show that the new expansions allow a precise determination of the strong coupling $\alpha_s$ from the hadronic decays of the $\tau$ lepton.
[ { "created": "Mon, 6 Dec 2010 11:14:35 GMT", "version": "v1" } ]
2015-03-17
[ [ "Caprini", "Irinel", "" ], [ "Fischer", "Jan", "" ] ]
We consider a new class of perturbation expansions, which incorporate in a systematic way the available information about the divergent character of the perturbation series in QCD. The new expansion functions, which replace the powers of the coupling, are defined by the analytic continuation in the Borel plane, achieved through an optimal conformal mapping. We consider several possibilities of implementing the known behaviour of the Borel transform near the leading singularities in the complex plane and using the corresponding expansions. These expansions have the same asymptotic convergence rate, but differ at low orders. We show that the new expansions allow a precise determination of the strong coupling $\alpha_s$ from the hadronic decays of the $\tau$ lepton.
1407.1827
Koji Ishiwata
Koji Ishiwata
Axino Dark Matter in Moduli-induced Baryogenesis
20 pages, 2 figures
null
10.1007/JHEP09(2014)122
DESY 14-114
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider axino dark matter in large R-parity violation (RPV). In moduli-dominated universe, axino is produced thermally or non-thermally via saxion decay, then late-decaying moduli dilute axino density, which results in the right abundance to explain the present dark matter. At the same time baryon asymmetry is generated due to moduli-induced baryogenesis via the large RPV. Axino is cosmologically stable in spite of the large RPV since its decay rate is suppressed by the axion decay constant, heavy squark mass or kinematics.
[ { "created": "Mon, 7 Jul 2014 19:59:58 GMT", "version": "v1" } ]
2015-06-22
[ [ "Ishiwata", "Koji", "" ] ]
We consider axino dark matter in large R-parity violation (RPV). In moduli-dominated universe, axino is produced thermally or non-thermally via saxion decay, then late-decaying moduli dilute axino density, which results in the right abundance to explain the present dark matter. At the same time baryon asymmetry is generated due to moduli-induced baryogenesis via the large RPV. Axino is cosmologically stable in spite of the large RPV since its decay rate is suppressed by the axion decay constant, heavy squark mass or kinematics.
hep-ph/0412094
Alvaro de Rujula
A. De Rujula
A Cannonball Model of Cosmic Rays
10 pages, 7 figures. To appear in the proceedings of the XIII International Symposium on Very High Energy Cosmic Ray Interactions, Pylos, Greece, 2004
null
null
null
hep-ph astro-ph
null
I outline a "Cannon-Ball" model of Cosmic Rays in which their distribution in the Galaxy, their total "luminosity", the broken power-law spectra with their observed slopes, the position of the knee(s) and ankle(s), and the alleged variations of composition with energy are all explained in terms of simple and "standard" physics.
[ { "created": "Tue, 7 Dec 2004 13:28:29 GMT", "version": "v1" } ]
2007-05-23
[ [ "De Rujula", "A.", "" ] ]
I outline a "Cannon-Ball" model of Cosmic Rays in which their distribution in the Galaxy, their total "luminosity", the broken power-law spectra with their observed slopes, the position of the knee(s) and ankle(s), and the alleged variations of composition with energy are all explained in terms of simple and "standard" physics.
1612.07252
S. Weinzierl
Robin Baumeister and Stefan Weinzierl
The matrix element method at next-to-leading order for arbitrary jet algorithms
16 pages, v2: version to be published
Phys. Rev. D 95, 036019 (2017)
10.1103/PhysRevD.95.036019
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The matrix element method usually employs leading-order matrix elements. We discuss the generalisation towards higher orders in perturbation theory and show how the matrix element method can be used at next-to-leading order for arbitrary infrared-safe jet algorithms. We discuss three variants at next-to-leading order. The first two variants work at the level of the jet momenta. The first variant adheres to strict fixed-order in perturbation theory. We present a method for the required integration over the radiation phase space. The second variant is inspired by the POWHEG method and works as the first variant at the level of the jet momenta. The third variant is a more exclusive POWHEG version. Here we resolve exactly one jet into two sub-jets. If the two sub-jets are resolved above a scale $p_\bot^{\mathrm{min}}$, the likelihood is computed from the POWHEG-modified real emission part, otherwise it is given by the POWHEG-modified virtual part.
[ { "created": "Wed, 21 Dec 2016 17:45:08 GMT", "version": "v1" }, { "created": "Wed, 8 Feb 2017 23:28:53 GMT", "version": "v2" } ]
2017-03-01
[ [ "Baumeister", "Robin", "" ], [ "Weinzierl", "Stefan", "" ] ]
The matrix element method usually employs leading-order matrix elements. We discuss the generalisation towards higher orders in perturbation theory and show how the matrix element method can be used at next-to-leading order for arbitrary infrared-safe jet algorithms. We discuss three variants at next-to-leading order. The first two variants work at the level of the jet momenta. The first variant adheres to strict fixed-order in perturbation theory. We present a method for the required integration over the radiation phase space. The second variant is inspired by the POWHEG method and works as the first variant at the level of the jet momenta. The third variant is a more exclusive POWHEG version. Here we resolve exactly one jet into two sub-jets. If the two sub-jets are resolved above a scale $p_\bot^{\mathrm{min}}$, the likelihood is computed from the POWHEG-modified real emission part, otherwise it is given by the POWHEG-modified virtual part.
hep-ph/9507279
Christoph Adam
C. Adam
Vacuum Functional and Fermion Condensate in the Massive Schwinger Model
7 pages, Latex file, no figures
Phys.Lett. B363 (1995) 79-84
10.1016/0370-2693(95)01181-O
BUTP-95/26
hep-ph
null
We derive a systematic procedure of computing the vacuum functional and fermion condensate of the massive Schwinger model via a perturbative expansion in the fermion mass. We compute numerical results for the first nontrivial order.
[ { "created": "Tue, 11 Jul 1995 21:43:09 GMT", "version": "v1" } ]
2009-10-28
[ [ "Adam", "C.", "" ] ]
We derive a systematic procedure of computing the vacuum functional and fermion condensate of the massive Schwinger model via a perturbative expansion in the fermion mass. We compute numerical results for the first nontrivial order.
1008.0476
Yoshio Kitadono
Yoshio Kitadono, Ryo Sahara, Tsuneo Uematsu, Takahiro Ueda
Resummation of large logarithms in the heavy quark effects on the parton distributions inside the virtual photon
12 pages, 9 eps figures (two figures are added)
Eur.Phys.J.C70:999-1007,2010
10.1140/epjc/s10052-010-1494-0
HUPD-1001, KUNS-2283, UTHEP-611
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We discuss the resummation of the large logarithmic terms appearing in the heavy quark effects on parton distribution functions inside the virtual photon. We incorporate heavy quark mass effects by changing the initial condition of the leading-order DGLAP evolution equation. In a certain kinematical limit, we recover the logarithmic terms of the next-to-leading order heavy quark effects obtained in the previous work. This method enables us to resum the large logarithmic terms due to heavy quark mass effects on the parton distributions in the virtual photon. We numerically calculate parton distributions using the formulae derived in this work, and discuss the property of the resummed heavy quark effects.
[ { "created": "Tue, 3 Aug 2010 08:01:12 GMT", "version": "v1" }, { "created": "Fri, 8 Oct 2010 11:19:35 GMT", "version": "v2" } ]
2010-12-15
[ [ "Kitadono", "Yoshio", "" ], [ "Sahara", "Ryo", "" ], [ "Uematsu", "Tsuneo", "" ], [ "Ueda", "Takahiro", "" ] ]
We discuss the resummation of the large logarithmic terms appearing in the heavy quark effects on parton distribution functions inside the virtual photon. We incorporate heavy quark mass effects by changing the initial condition of the leading-order DGLAP evolution equation. In a certain kinematical limit, we recover the logarithmic terms of the next-to-leading order heavy quark effects obtained in the previous work. This method enables us to resum the large logarithmic terms due to heavy quark mass effects on the parton distributions in the virtual photon. We numerically calculate parton distributions using the formulae derived in this work, and discuss the property of the resummed heavy quark effects.
hep-ph/0502047
Lotfi Boubekeur
Lotfi Boubekeur and David. H. Lyth (Lancaster University)
Hilltop Inflation
Latex, 20 pages, 5 figures. Minor changes, references added
JCAP 0507 (2005) 010
10.1088/1475-7516/2005/07/010
null
hep-ph astro-ph gr-qc hep-th
null
We study `hilltop' inflation, in which inflation takes place near a maximum of the potential. Viewed as a model of inflation after the observable Universe leaves the horizon (observable inflation) hilltop inflation is rather generic. If the potential steepens monotonically, observable hilltop inflation gives a tiny tensor fraction (r< 0.002). The usual F- and D-term models may easily be transmuted to hilltop models by Planck-suppressed terms, making them more natural. The only commonly-considered model of observable inflation which is definitely not hilltop is tree-level hybrid inflation. Viewed instead as an initial condition, we explain that hilltop inflation is more generic than seems to have been previously recognized, adding thereby to the credibility of the idea that eternal inflation provides the pre-inflationary initial condition.
[ { "created": "Fri, 4 Feb 2005 20:51:57 GMT", "version": "v1" }, { "created": "Wed, 2 Mar 2005 17:35:42 GMT", "version": "v2" } ]
2009-11-11
[ [ "Boubekeur", "Lotfi", "", "Lancaster University" ], [ "Lyth", "David. H.", "", "Lancaster University" ] ]
We study `hilltop' inflation, in which inflation takes place near a maximum of the potential. Viewed as a model of inflation after the observable Universe leaves the horizon (observable inflation) hilltop inflation is rather generic. If the potential steepens monotonically, observable hilltop inflation gives a tiny tensor fraction (r< 0.002). The usual F- and D-term models may easily be transmuted to hilltop models by Planck-suppressed terms, making them more natural. The only commonly-considered model of observable inflation which is definitely not hilltop is tree-level hybrid inflation. Viewed instead as an initial condition, we explain that hilltop inflation is more generic than seems to have been previously recognized, adding thereby to the credibility of the idea that eternal inflation provides the pre-inflationary initial condition.
hep-ph/9708312
John Ellis
John Ellis (CERN) and Douglas Ross (U. of Southampton)
Calculations of One-Loop Supersymmetric Corrections to Large-E_T Jet Cross Sections
21 pages, LaTex, 16 figures as ps files
Eur.Phys.J.C4:339-349,1998
10.1007/s100520050212
CERN-TH/97-192, SHEP-97-16
hep-ph
null
We have calculated the one-loop supersymmetric corrections to the 2 to 2 parton scattering subprocesses antiq q to antiq q, antiq q to g g, g q to g q and g g to g g, including form-factor corrections and box diagrams with internal squarks and gluinos of arbitrary mass. In general, these exhibit cusps at the corresponding direct-channel sparticle thresholds. We use these calculations to make numerical estimates of the possible threshold effects at the Fermilab Tevatron collider and at the LHC, which depend on the rapidity range selected, but can be as large as a few percent. These effects are diluted in the integrated large-E_T cross section, where they are negative.
[ { "created": "Tue, 12 Aug 1997 01:37:48 GMT", "version": "v1" } ]
2009-09-11
[ [ "Ellis", "John", "", "CERN" ], [ "Ross", "Douglas", "", "U. of Southampton" ] ]
We have calculated the one-loop supersymmetric corrections to the 2 to 2 parton scattering subprocesses antiq q to antiq q, antiq q to g g, g q to g q and g g to g g, including form-factor corrections and box diagrams with internal squarks and gluinos of arbitrary mass. In general, these exhibit cusps at the corresponding direct-channel sparticle thresholds. We use these calculations to make numerical estimates of the possible threshold effects at the Fermilab Tevatron collider and at the LHC, which depend on the rapidity range selected, but can be as large as a few percent. These effects are diluted in the integrated large-E_T cross section, where they are negative.
0805.3310
Andreas Brandhuber
Andreas Brandhuber, Massimiliano Vincon
MHV One-Loop Amplitudes in Yang-Mills from Generalised Unitarity
20 pages, 4 figures; v3 version published in JHEP
JHEP 0811:078,2008
10.1088/1126-6708/2008/11/078
QMUL-PH-08-01
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this letter, we exploit generalised unitarity in order to calculate the cut-constructible part of one-loop amplitudes in non-supersymmetric Yang-Mills theory. In particular, we rederive the n-gluon MHV amplitudes for both the adjacent and non-adjacent gluon helicity configurations from 3- and 4-particle cuts alone.
[ { "created": "Wed, 21 May 2008 19:44:18 GMT", "version": "v1" }, { "created": "Thu, 29 May 2008 16:43:00 GMT", "version": "v2" }, { "created": "Fri, 24 Apr 2009 15:15:55 GMT", "version": "v3" } ]
2010-02-03
[ [ "Brandhuber", "Andreas", "" ], [ "Vincon", "Massimiliano", "" ] ]
In this letter, we exploit generalised unitarity in order to calculate the cut-constructible part of one-loop amplitudes in non-supersymmetric Yang-Mills theory. In particular, we rederive the n-gluon MHV amplitudes for both the adjacent and non-adjacent gluon helicity configurations from 3- and 4-particle cuts alone.
2205.08171
Weikang Lin
Weikang Lin and Tsutomu Yanagida
Confronting the Galactic 511 keV emission with $B-L$ gauge boson dark matter
5 pages, 2 figure; matches version published in PRD
Phys. Rev. D 106, 075012 (2022)
10.1103/PhysRevD.106.075012
null
hep-ph astro-ph.CO astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The $B-L$ gauge symmetry motivated from the successful generation of the seesaw mechanism and leptogenesis. We show that if the $B-L$ gauge boson constitutes a small fraction of the dark matter (DM) it can explain the Galactic $511$ keV emission via the decay into an electron-positron pair. We find the model parameter space that is consistent with the seesaw mechanism, cosmologically viable, and accounting for the amplitude of the Galactic positron line. From this parameter space we derive an upper bound of the gauge boson mass and then an bound of the positron injection energy $\lesssim3$ MeV. This derived energy bound is consistent with the observational upper limit of the injection energy. The resultant model predicts the $B-L$ breaking scale to be in a relatively narrow range, i.e., $V_{B\textrm{--}L}\sim10^{15} \textrm{--} 10^{16} $GeV, which is consistent with a Grand Unification (GUT) scale seesaw mechanism. The model is consistent in several phenomenologies, suggesting their common origin from the B-L symmetry breaking.
[ { "created": "Tue, 17 May 2022 08:19:19 GMT", "version": "v1" }, { "created": "Thu, 13 Oct 2022 11:04:48 GMT", "version": "v2" } ]
2022-10-14
[ [ "Lin", "Weikang", "" ], [ "Yanagida", "Tsutomu", "" ] ]
The $B-L$ gauge symmetry motivated from the successful generation of the seesaw mechanism and leptogenesis. We show that if the $B-L$ gauge boson constitutes a small fraction of the dark matter (DM) it can explain the Galactic $511$ keV emission via the decay into an electron-positron pair. We find the model parameter space that is consistent with the seesaw mechanism, cosmologically viable, and accounting for the amplitude of the Galactic positron line. From this parameter space we derive an upper bound of the gauge boson mass and then an bound of the positron injection energy $\lesssim3$ MeV. This derived energy bound is consistent with the observational upper limit of the injection energy. The resultant model predicts the $B-L$ breaking scale to be in a relatively narrow range, i.e., $V_{B\textrm{--}L}\sim10^{15} \textrm{--} 10^{16} $GeV, which is consistent with a Grand Unification (GUT) scale seesaw mechanism. The model is consistent in several phenomenologies, suggesting their common origin from the B-L symmetry breaking.
2005.08980
Paul Archer-Smith
Paul Archer-Smith, Yue Zhang
Higgs Portal From The Atmosphere To Hyper-K
5 pages, 4 figures
Physics Letters B 817 (2021) 136309
10.1016/j.physletb.2021.136309
null
hep-ph hep-ex
http://creativecommons.org/licenses/by/4.0/
A light Higgs portal scalar could be abundantly produced in the earth's atmosphere and decay in large-volume neutrino detectors. We point out that the Hyper-Kamiokande detector bears a strong discovery potential of probing such particles in an uncharted parameter space that is actively explored by intensity frontier experiments including rare kaon decays. The signal we propose to look for is electron-positron pair creation that manifests as a double-ring appearing from the same vertex. Most of these pairs originate from zenith angles above the Hyper-K detector's horizon. This search can be generalized to other new light states and is highly complementary to beam experiments.
[ { "created": "Mon, 18 May 2020 18:00:03 GMT", "version": "v1" }, { "created": "Fri, 30 Apr 2021 20:39:28 GMT", "version": "v2" } ]
2021-05-04
[ [ "Archer-Smith", "Paul", "" ], [ "Zhang", "Yue", "" ] ]
A light Higgs portal scalar could be abundantly produced in the earth's atmosphere and decay in large-volume neutrino detectors. We point out that the Hyper-Kamiokande detector bears a strong discovery potential of probing such particles in an uncharted parameter space that is actively explored by intensity frontier experiments including rare kaon decays. The signal we propose to look for is electron-positron pair creation that manifests as a double-ring appearing from the same vertex. Most of these pairs originate from zenith angles above the Hyper-K detector's horizon. This search can be generalized to other new light states and is highly complementary to beam experiments.
1201.4893
Federico Galli
Federico Galli, Alberto Mariotti
Soft Spectrum in Yukawa-Gauge Mediation
22 pages, 4 figures; v2: minor corrections, published version
null
10.1007/JHEP06(2012)055
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We introduce a model independent parametrization for a subclass of gauge mediated theories, which we refer to as Yukawa-gauge mediation. Within this formalism we study the resulting soft masses in the visible spectrum. We find general expressions for the gaugino and scalar masses. Under generic conditions, the gaugino mass is screened, vanishing at first order in the SUSY breaking scale.
[ { "created": "Mon, 23 Jan 2012 23:09:35 GMT", "version": "v1" }, { "created": "Fri, 22 Jun 2012 16:31:43 GMT", "version": "v2" } ]
2012-06-25
[ [ "Galli", "Federico", "" ], [ "Mariotti", "Alberto", "" ] ]
We introduce a model independent parametrization for a subclass of gauge mediated theories, which we refer to as Yukawa-gauge mediation. Within this formalism we study the resulting soft masses in the visible spectrum. We find general expressions for the gaugino and scalar masses. Under generic conditions, the gaugino mass is screened, vanishing at first order in the SUSY breaking scale.
hep-ph/0609105
Ian Balitsky
I Balitsky
Quark contribution to the small-$x$ evolution of color dipole
21 pages, 11 eps figures
Phys.Rev.D75:014001,2007
10.1103/PhysRevD.75.014001
JLAB-THY-06-541
hep-ph
null
The small-$x$ deep inelastic scattering in the saturation region is governed by the non-linear evolution of Wilson-lines operators. In the leading logarithmic approximation it is given by the BK equation for the evolution of color dipoles. In the NLO the nonlinear equation gets contributions from quark and gluon loops. In this paper I calculate the quark-loop contribution to small-x evolution of Wilson lines in the NLO. It turns out that there are no new operators at the one-loop level - just as at the tree level, the high-energy scattering can be described in terms of Wilson lines. In addition, from the analysis of quark loops I find that the argument of coupling constant in the BK equation is determined by the size of the parent dipole rather than by the size of produced dipoles. These results are to be supported by future calculation of gluon loops.
[ { "created": "Mon, 11 Sep 2006 19:49:19 GMT", "version": "v1" } ]
2008-11-26
[ [ "Balitsky", "I", "" ] ]
The small-$x$ deep inelastic scattering in the saturation region is governed by the non-linear evolution of Wilson-lines operators. In the leading logarithmic approximation it is given by the BK equation for the evolution of color dipoles. In the NLO the nonlinear equation gets contributions from quark and gluon loops. In this paper I calculate the quark-loop contribution to small-x evolution of Wilson lines in the NLO. It turns out that there are no new operators at the one-loop level - just as at the tree level, the high-energy scattering can be described in terms of Wilson lines. In addition, from the analysis of quark loops I find that the argument of coupling constant in the BK equation is determined by the size of the parent dipole rather than by the size of produced dipoles. These results are to be supported by future calculation of gluon loops.
0906.2537
Idan Shilon
Eduardo I. Guendelman, Idan Shilon, Giovanni Cantatore and Konstantin Zioutas
Photon Production From The Scattering of Axions Out of a Solenoidal Magnetic Field
19 pages, 1 figure, added analysis of our results in the astrophysical extension
JCAP 1006:031,2010
10.1088/1475-7516/2010/06/031
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We calculate the total cross section for the production of photons from the scattering of axions by a strong inhomogeneous magnetic field in the form of a 2D delta-function, a cylindrical step function and a 2D Gaussian distribution, which can be approximately produced by a solenoidal current. The theoretical result is used to estimate the axion-photon conversion probability which could be expected in a reasonable experimental situation. The calculated conversion probabilities for QCD inspired axions are bigger by a factor of 2.67 (for the cylindrical step function case) than those derived by applying the celebrated 1D calculation of the (inverse) coherent Primakoff effect. We also consider scattering at a resonance $E_{axion} \sim m_{axion}$, which corresponds to the scattering from a delta-function and gives the most enhanced results. Finally, we analyze the results of this work in the astrophysical extension to suggest a way in which they may be directed to a solution to some basic solar physics problems and, in particular, the coronal heating problem.
[ { "created": "Sun, 14 Jun 2009 13:46:00 GMT", "version": "v1" }, { "created": "Mon, 10 Aug 2009 19:21:27 GMT", "version": "v2" }, { "created": "Wed, 17 Mar 2010 12:40:20 GMT", "version": "v3" } ]
2014-11-20
[ [ "Guendelman", "Eduardo I.", "" ], [ "Shilon", "Idan", "" ], [ "Cantatore", "Giovanni", "" ], [ "Zioutas", "Konstantin", "" ] ]
We calculate the total cross section for the production of photons from the scattering of axions by a strong inhomogeneous magnetic field in the form of a 2D delta-function, a cylindrical step function and a 2D Gaussian distribution, which can be approximately produced by a solenoidal current. The theoretical result is used to estimate the axion-photon conversion probability which could be expected in a reasonable experimental situation. The calculated conversion probabilities for QCD inspired axions are bigger by a factor of 2.67 (for the cylindrical step function case) than those derived by applying the celebrated 1D calculation of the (inverse) coherent Primakoff effect. We also consider scattering at a resonance $E_{axion} \sim m_{axion}$, which corresponds to the scattering from a delta-function and gives the most enhanced results. Finally, we analyze the results of this work in the astrophysical extension to suggest a way in which they may be directed to a solution to some basic solar physics problems and, in particular, the coronal heating problem.
hep-ph/0202184
Vladimir Lugovoi
Vladimir Lugovoi
Gluon exchange and p_{T} distribution
23 pages, Latex, 7 figures
null
null
null
hep-ph
null
It is shown that even if a quark q is on the mass shell, the quark q' created via vacuum pair production in the process q -> h + q' has wide distribution for its spacelike virtuality, and so at the end of daughter string (q'\bar{q}) there is a parton having wide distributed spacelike virtuality. However, the essence of the parton model is to regard a high energy hadron-like cluster as a collection of quasifree partons. Therefore we use a set of some principles of string model, formulated, for example, by Andersson and Nilsson, that gluons move like localised particles carrying energy momentum between quark and antiquark at the endpoints of string, and so we take into account they go on the mass shell before the break of daughter string occurs. It is stressed, the gluons carry also transverse momentum which could be connected with spacelike virtuality of quark at the end of string. Some approximations to describe the gluon exchange are studied and results of Monte Carlo calculations for antiproton-proton interactions are given.
[ { "created": "Tue, 19 Feb 2002 12:57:09 GMT", "version": "v1" } ]
2007-05-23
[ [ "Lugovoi", "Vladimir", "" ] ]
It is shown that even if a quark q is on the mass shell, the quark q' created via vacuum pair production in the process q -> h + q' has wide distribution for its spacelike virtuality, and so at the end of daughter string (q'\bar{q}) there is a parton having wide distributed spacelike virtuality. However, the essence of the parton model is to regard a high energy hadron-like cluster as a collection of quasifree partons. Therefore we use a set of some principles of string model, formulated, for example, by Andersson and Nilsson, that gluons move like localised particles carrying energy momentum between quark and antiquark at the endpoints of string, and so we take into account they go on the mass shell before the break of daughter string occurs. It is stressed, the gluons carry also transverse momentum which could be connected with spacelike virtuality of quark at the end of string. Some approximations to describe the gluon exchange are studied and results of Monte Carlo calculations for antiproton-proton interactions are given.
hep-ph/0209293
Hannes Pichl
Hannes Pichl (PSI Villigen)
Electromagnetic radiative corrections to pionic beta decay \pi^+ to \pi^0 e^+ \nu_e
4 pages, contribution to Proc. of QCD 02, Montpellier, July 2002
Nucl.Phys.Proc.Suppl.121:191-194,2003
10.1016/S0920-5632(03)01844-9
PSI-PR-02-09
hep-ph
null
Pionic beta decay \pi^+ to \pi^0 e^+ \nu_e is analyzed in chiral perturbation theory with virtual photons and leptons. All electromagnetic corrections up to order e^2 p^2 are taken into account. Theoretical results are confronted with preliminary data from a PSI measurement and a value for the CKM matrix element |Vud| is given. Although the precision is presently still below the one of existing determinations of |Vud|, an analysis of pionic beta decay, based on a systematic treatment within a low-energy effective field theory, may become a useful alternative.
[ { "created": "Wed, 25 Sep 2002 09:25:31 GMT", "version": "v1" } ]
2010-11-23
[ [ "Pichl", "Hannes", "", "PSI Villigen" ] ]
Pionic beta decay \pi^+ to \pi^0 e^+ \nu_e is analyzed in chiral perturbation theory with virtual photons and leptons. All electromagnetic corrections up to order e^2 p^2 are taken into account. Theoretical results are confronted with preliminary data from a PSI measurement and a value for the CKM matrix element |Vud| is given. Although the precision is presently still below the one of existing determinations of |Vud|, an analysis of pionic beta decay, based on a systematic treatment within a low-energy effective field theory, may become a useful alternative.
hep-ph/0102297
Howard E. Haber
Athanasios Dedes and Howard E. Haber
Can the Higgs sector contribute significantly to the muon anomalous magnetic moment?
16 pages, 1 figure, JHEP style, typographical errors and one reference corrected, a new footnote, paragraph and one new reference added
JHEP 0105:006,2001
10.1088/1126-6708/2001/05/006
SCIPP-01/10
hep-ph
null
A light CP-even Higgs boson (h) with a mass of about 10 GeV could explain the recent BNL measurement of the muon anomalous magnetic moment, in the framework of a general CP-conserving two-Higgs-doublet extension of the Standard Model with no tree-level flavor-changing neutral Higgs couplings. However, the allowed Higgs mass window is quite small and the corresponding model parameters are very constrained. The Higgs sector can contribute significantly to the observed BNL result for g-2 without violating known experimental constraints only if the hZZ coupling (approximately) vanishes and m_h lies between the Upsilon mass and 2m_B.
[ { "created": "Fri, 23 Feb 2001 19:15:11 GMT", "version": "v1" }, { "created": "Sun, 25 Feb 2001 19:22:04 GMT", "version": "v2" }, { "created": "Fri, 2 Mar 2001 15:57:46 GMT", "version": "v3" } ]
2010-02-03
[ [ "Dedes", "Athanasios", "" ], [ "Haber", "Howard E.", "" ] ]
A light CP-even Higgs boson (h) with a mass of about 10 GeV could explain the recent BNL measurement of the muon anomalous magnetic moment, in the framework of a general CP-conserving two-Higgs-doublet extension of the Standard Model with no tree-level flavor-changing neutral Higgs couplings. However, the allowed Higgs mass window is quite small and the corresponding model parameters are very constrained. The Higgs sector can contribute significantly to the observed BNL result for g-2 without violating known experimental constraints only if the hZZ coupling (approximately) vanishes and m_h lies between the Upsilon mass and 2m_B.
1612.00795
James Gainer
Howard Baer, Vernon Barger, James S. Gainer, Peisi Huang, Michael Savoy, Dibyashree Sengupta and Xerxes Tata
Gluino reach and mass extraction at the LHC in radiatively-driven natural SUSY
25 pages + frontpage. 13 figures consisting of 20 image files
null
10.1140/epjc/s10052-017-5067-3
UH-511-1269-16
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Radiatively-driven natural SUSY (RNS) models enjoy electroweak naturalness at the $10\%$ level while respecting LHC sparticle and Higgs mass constraints. Gluino and top squark masses can range up to several TeV (with other squarks even heavier) but a set of light Higgsinos are required with mass not too far above $m_h\sim 125$ GeV. Within the RNS framework, gluinos dominantly decay via ${\tilde g} \to t{\tilde t}_1^{*},\ \bar{t}{\tilde t}_1 \to t\bar{t}{\widetilde Z}_{1,2}$ or $t\bar{b}{\widetilde W}_1^-+c.c.$, where the decay products of the higgsino-like ${\widetilde W}_1$ and ${\widetilde Z}_2$ are very soft. Gluino pair production is, therefore, signalled by events with up to four hard $b$-jets and large ${\not\!\!{E_T}}$. We devise a set of cuts to isolate a relatively pure gluino sample at the (high luminosity) LHC and show that in the RNS model with very heavy squarks, the gluino signal will be accessible for $m_{{\tilde g}} < 2400 \ (2800)$ GeV for an integrated luminosity of 300 (3000) fb$^{-1}$. We also show that the measurement of the rate of gluino events in the clean sample mentioned above allows for a determination of $m_{{\tilde g}}$ with a statistical precision of $2.5-5\%$ (depending on the integrated luminosity and the gluino mass) over the range of gluino masses where a $5\sigma$ discovery is possible at the LHC.
[ { "created": "Fri, 2 Dec 2016 19:16:23 GMT", "version": "v1" } ]
2017-09-13
[ [ "Baer", "Howard", "" ], [ "Barger", "Vernon", "" ], [ "Gainer", "James S.", "" ], [ "Huang", "Peisi", "" ], [ "Savoy", "Michael", "" ], [ "Sengupta", "Dibyashree", "" ], [ "Tata", "Xerxes", "" ] ]
Radiatively-driven natural SUSY (RNS) models enjoy electroweak naturalness at the $10\%$ level while respecting LHC sparticle and Higgs mass constraints. Gluino and top squark masses can range up to several TeV (with other squarks even heavier) but a set of light Higgsinos are required with mass not too far above $m_h\sim 125$ GeV. Within the RNS framework, gluinos dominantly decay via ${\tilde g} \to t{\tilde t}_1^{*},\ \bar{t}{\tilde t}_1 \to t\bar{t}{\widetilde Z}_{1,2}$ or $t\bar{b}{\widetilde W}_1^-+c.c.$, where the decay products of the higgsino-like ${\widetilde W}_1$ and ${\widetilde Z}_2$ are very soft. Gluino pair production is, therefore, signalled by events with up to four hard $b$-jets and large ${\not\!\!{E_T}}$. We devise a set of cuts to isolate a relatively pure gluino sample at the (high luminosity) LHC and show that in the RNS model with very heavy squarks, the gluino signal will be accessible for $m_{{\tilde g}} < 2400 \ (2800)$ GeV for an integrated luminosity of 300 (3000) fb$^{-1}$. We also show that the measurement of the rate of gluino events in the clean sample mentioned above allows for a determination of $m_{{\tilde g}}$ with a statistical precision of $2.5-5\%$ (depending on the integrated luminosity and the gluino mass) over the range of gluino masses where a $5\sigma$ discovery is possible at the LHC.
hep-ph/9411312
Bonnie Friedman
Xiangdong Ji, MIT
Infrared Renormalons and Power Corrections in Deep-Inelastic Sum Rules
18 pages, ReVTeX, 2 figures (not available by postscript yet)
Nucl.Phys. B448 (1995) 51-66
10.1016/0550-3213(95)00295-4
MIT-CTP-2381
hep-ph
null
Infrared renormalons and $1/Q^2$ power corrections in deep-inelastic sum rules are studied. The renormalization of operators with power divergence are discussed. The higher-twist terms in the operator product expansion are shown to account for the residual soft contributions survived from the Kinoshita-Lee-Nauenberg type of cancellation in Feynman diagrams. The presence of some degree of arbitrariness in the twist separation allows one to define the most convenient higher-twist operators suitable for a particular non-perturbative method. The discussion is focused on the Bjorken sum rule, for which the $1/Q^2$ corrections are considered on a lattice.
[ { "created": "Wed, 16 Nov 1994 19:54:30 GMT", "version": "v1" } ]
2015-06-25
[ [ "Ji", "Xiangdong", "" ], [ "MIT", "", "" ] ]
Infrared renormalons and $1/Q^2$ power corrections in deep-inelastic sum rules are studied. The renormalization of operators with power divergence are discussed. The higher-twist terms in the operator product expansion are shown to account for the residual soft contributions survived from the Kinoshita-Lee-Nauenberg type of cancellation in Feynman diagrams. The presence of some degree of arbitrariness in the twist separation allows one to define the most convenient higher-twist operators suitable for a particular non-perturbative method. The discussion is focused on the Bjorken sum rule, for which the $1/Q^2$ corrections are considered on a lattice.
1011.5453
Ulrich Jentschura
U. D. Jentschura
Lamb Shift in Muonic Hydrogen. II. Analysis of the Discrepancy of Theory and Experiment
19 pages; LaTeX; literature references have been updated at the time of submission to a scientific journal
Ann.Phys.(N.Y.) 326 (2011) 516-533
10.1016/j.aop.2010.11.011
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Currently, both the g factor measurement of the muon as well as the Lamb shift 2S-2P measurement in muonic hydrogen are in disagreement with theory. Here, we investigate possible theoretical explanations, including proton structure effects and small modifications of the vacuum polarization potential. In particular, we investigate a conceivable small modification of the spectral function of vacuum polarization in between the electron and muon energy scales due to a virtual millicharged particle and due to an unstable vector boson originating from a hidden sector of an extended standard model. We find that a virtual millicharged particle which could explain the muonic Lamb shift discrepancy alters theoretical predictions for the muon anomalous magnetic moment by many standard deviations and therefore is in conflict with experiment. Also, we find no parameterizations of an unstable virtual vector boson which could simultaneously explain both "muonic" discrepancies without significantly altering theoretical predictions for electronic hydrogen, where theory and experiment currently are in excellent agreement. A process-dependent correction involving electron screening is evaluated to have the right sign and order-of-magnitude to explain the observed effect in muonic hydrogen. Additional experimental evidence from light muonic atoms and ions is needed in order to reach further clarification.
[ { "created": "Wed, 24 Nov 2010 18:50:58 GMT", "version": "v1" } ]
2012-07-03
[ [ "Jentschura", "U. D.", "" ] ]
Currently, both the g factor measurement of the muon as well as the Lamb shift 2S-2P measurement in muonic hydrogen are in disagreement with theory. Here, we investigate possible theoretical explanations, including proton structure effects and small modifications of the vacuum polarization potential. In particular, we investigate a conceivable small modification of the spectral function of vacuum polarization in between the electron and muon energy scales due to a virtual millicharged particle and due to an unstable vector boson originating from a hidden sector of an extended standard model. We find that a virtual millicharged particle which could explain the muonic Lamb shift discrepancy alters theoretical predictions for the muon anomalous magnetic moment by many standard deviations and therefore is in conflict with experiment. Also, we find no parameterizations of an unstable virtual vector boson which could simultaneously explain both "muonic" discrepancies without significantly altering theoretical predictions for electronic hydrogen, where theory and experiment currently are in excellent agreement. A process-dependent correction involving electron screening is evaluated to have the right sign and order-of-magnitude to explain the observed effect in muonic hydrogen. Additional experimental evidence from light muonic atoms and ions is needed in order to reach further clarification.
hep-ph/0105033
Bugra Borasoy
B. Borasoy
Threshold eta and eta' electroproduction off nucleons
24 pages, 7 figures
Phys.Rev. D63 (2001) 094015
10.1103/PhysRevD.63.094015
null
hep-ph nucl-th
null
The electroproduction of eta and eta' mesons on the proton and the neutron is investigated at tree level within the framework of U(3) chiral perturbation theory. In addition to the Born terms low-lying resonances such as the vector mesons and J^P= 1/2^+, 1/2^- baryon resonances are included explicitly and their contributions are calculated. Results for the separated differential cross sections are presented.
[ { "created": "Thu, 3 May 2001 15:33:11 GMT", "version": "v1" } ]
2009-11-07
[ [ "Borasoy", "B.", "" ] ]
The electroproduction of eta and eta' mesons on the proton and the neutron is investigated at tree level within the framework of U(3) chiral perturbation theory. In addition to the Born terms low-lying resonances such as the vector mesons and J^P= 1/2^+, 1/2^- baryon resonances are included explicitly and their contributions are calculated. Results for the separated differential cross sections are presented.
1205.2557
Alexandre Arbey
A. Arbey, M. Battaglia, F. Mahmoudi
Light Neutralino Dark Matter in the pMSSM: Implications of LEP, LHC and Dark Matter Searches on SUSY Particle Spectra
11 pages, 12 figures
Eur. Phys. J. C72 (2012) 2169
10.1140/epjc/s10052-012-2169-9
CERN-PH-TH/2012-123
hep-ph astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate the viability of light neutralino scenarios as promoted by dark matter direct detection experiments. Using high statistics scans in the pMSSM we have identified several scenarios which give rise to very light neutralinos with large direct detection scattering cross sections. Our results are challenged with constraints from dark matter relic density, direct detection, indirect detection, as well as flavour physics, electroweak precision tests, LEP and Tevatron limits, LHC limits on SUSY, Higgs and monojet searches. In particular we study the effect of a Higgs boson in the range 122.5 < Mh < 127.5 GeV. We show that several scenarios emerge in agreement with all the constraints, and we study their characteristics and the LHC sensitivity.
[ { "created": "Fri, 11 May 2012 15:28:42 GMT", "version": "v1" } ]
2012-10-08
[ [ "Arbey", "A.", "" ], [ "Battaglia", "M.", "" ], [ "Mahmoudi", "F.", "" ] ]
We investigate the viability of light neutralino scenarios as promoted by dark matter direct detection experiments. Using high statistics scans in the pMSSM we have identified several scenarios which give rise to very light neutralinos with large direct detection scattering cross sections. Our results are challenged with constraints from dark matter relic density, direct detection, indirect detection, as well as flavour physics, electroweak precision tests, LEP and Tevatron limits, LHC limits on SUSY, Higgs and monojet searches. In particular we study the effect of a Higgs boson in the range 122.5 < Mh < 127.5 GeV. We show that several scenarios emerge in agreement with all the constraints, and we study their characteristics and the LHC sensitivity.
hep-ph/0011125
Scimemi Ignazio
I. Scimemi
epsilon'/epsilon in the Standard Model
Talk presented at QCD2000, Montpellier july 2000
Nucl.Phys.Proc.Suppl. 96 (2001) 342-345
10.1016/S0920-5632(01)01151-3
IFIC/00-65
hep-ph
null
In order to provide an estimate of eps'/eps several effective theories and physical effects have to be disentangled. In this talk I discuss how it is possible to predict eps '/eps taking into account all sources of large logs. The numerical result one obtains, $\eps '/\eps \sim (1.7\pm 0.6) \cdot 10^{-4}$, is in good agreement with present measurements.
[ { "created": "Thu, 9 Nov 2000 09:46:52 GMT", "version": "v1" } ]
2016-09-06
[ [ "Scimemi", "I.", "" ] ]
In order to provide an estimate of eps'/eps several effective theories and physical effects have to be disentangled. In this talk I discuss how it is possible to predict eps '/eps taking into account all sources of large logs. The numerical result one obtains, $\eps '/\eps \sim (1.7\pm 0.6) \cdot 10^{-4}$, is in good agreement with present measurements.
0808.3340
Diego Aristizabal
D. Aristizabal Sierra, Jisuke Kubo, D. Restrepo, Daijiro Suematsu, Oscar Zapata
Radiative seesaw: Warm dark matter, collider and lepton flavour violating signals
25 pages, 7 figures. A few clarifications and references added, collider physics improved, conclusions unchanged. Version matches publication in PRD (Title changed in journal)
Phys.Rev.D79:013011,2009
10.1103/PhysRevD.79.013011
KANAZAWA-08-08
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Extending the standard model with three right-handed neutrinos ($N_k$) and a second Higgs doublet ($\eta$), odd under the discrete parity symmetry $Z_2$, Majorana neutrino masses can be generated at 1-loop order. In the resulting model, the lightest stable particle, either a boson or a fermion, might be a dark matter candidate. Here we assume a specific mass spectrum ($M_1\ll M_2 < M_3 < m_\eta$) and derive its consequences for dark matter and collider phenomenology. We show that (i) the lightest right-handed neutrino is a warm dark matter particle that can give a $\sim$10% contribution to the dark matter density; (ii) several decay branching ratios of the charged scalar can be predicted from measured neutrino data. Especially interesting is that large lepton flavour violating rates in muon and tau final states are expected. Finally, we derive upper bounds on the right-handed neutrino Yukawa couplings from the current experimental limit on $Br(\mu\to e\gamma)$.
[ { "created": "Mon, 25 Aug 2008 12:10:08 GMT", "version": "v1" }, { "created": "Mon, 8 Sep 2008 12:57:09 GMT", "version": "v2" }, { "created": "Thu, 29 Jan 2009 09:51:00 GMT", "version": "v3" } ]
2009-02-10
[ [ "Sierra", "D. Aristizabal", "" ], [ "Kubo", "Jisuke", "" ], [ "Restrepo", "D.", "" ], [ "Suematsu", "Daijiro", "" ], [ "Zapata", "Oscar", "" ] ]
Extending the standard model with three right-handed neutrinos ($N_k$) and a second Higgs doublet ($\eta$), odd under the discrete parity symmetry $Z_2$, Majorana neutrino masses can be generated at 1-loop order. In the resulting model, the lightest stable particle, either a boson or a fermion, might be a dark matter candidate. Here we assume a specific mass spectrum ($M_1\ll M_2 < M_3 < m_\eta$) and derive its consequences for dark matter and collider phenomenology. We show that (i) the lightest right-handed neutrino is a warm dark matter particle that can give a $\sim$10% contribution to the dark matter density; (ii) several decay branching ratios of the charged scalar can be predicted from measured neutrino data. Especially interesting is that large lepton flavour violating rates in muon and tau final states are expected. Finally, we derive upper bounds on the right-handed neutrino Yukawa couplings from the current experimental limit on $Br(\mu\to e\gamma)$.
1103.2145
Eduardo Basso
E. A. F. Basso, M. B. Gay Ducati, E. G. de Oliveira
Momentum space saturation model for deep inelastic scattering and single inclusive hadron production
10 pages, 7 figures
Phys.Rev.D84:034024,2011
10.1103/PhysRevD.84.034024
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We show how the AGBS model, originally developed for deep inelastic scattering applied to HERA data on the proton structure function, can also describe the RHIC data on single inclusive hadron yield for $d+Au$ and $p+p$ collisions through a new simultaneous fit. The single inclusive hadron production is modeled through the color glass condensate, which uses the quark(and gluon)--condensate amplitudes in momentum space. The AGBS model is also a momentum space model based on the asymptotic solutions of the BK equation, although a different definition of the Fourier transform is used. This aspect is overcome and a description entirely in transverse momentum of both processes arises for the first time. The small difference between the simultaneous fit and the one for HERA data alone suggests that the AGBS model describes very well both kind of processes and thus emerges as a good tool to investigate the inclusive hadron production data. We use this model for predictions at LHC energies, which agree very well with available experimental data.
[ { "created": "Thu, 10 Mar 2011 21:30:21 GMT", "version": "v1" } ]
2011-09-08
[ [ "Basso", "E. A. F.", "" ], [ "Ducati", "M. B. Gay", "" ], [ "de Oliveira", "E. G.", "" ] ]
We show how the AGBS model, originally developed for deep inelastic scattering applied to HERA data on the proton structure function, can also describe the RHIC data on single inclusive hadron yield for $d+Au$ and $p+p$ collisions through a new simultaneous fit. The single inclusive hadron production is modeled through the color glass condensate, which uses the quark(and gluon)--condensate amplitudes in momentum space. The AGBS model is also a momentum space model based on the asymptotic solutions of the BK equation, although a different definition of the Fourier transform is used. This aspect is overcome and a description entirely in transverse momentum of both processes arises for the first time. The small difference between the simultaneous fit and the one for HERA data alone suggests that the AGBS model describes very well both kind of processes and thus emerges as a good tool to investigate the inclusive hadron production data. We use this model for predictions at LHC energies, which agree very well with available experimental data.
1903.09617
Ashutosh Alok
Ashutosh Kumar Alok, Amol Dighe, Shireen Gangal, Dinesh Kumar
Continuing search for new physics in $b \to s \mu \mu$ decays: two operators at a time
20 pages, 2 figures; Added an appendix with updated fit results by taking into account the LHCb results between March 2019 and March 2021 (including R_K update in Moriond 2021)
JHEP06(2019)089
10.1007/JHEP06(2019)089
TIFR/TH/19-6
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The anomalies in the measurements of observables involving $b \to s \mu\mu$ decays, namely $R_K$, $R_{K^*}$, $P_5^{\prime}$, and $B_s^\phi$, may be addressed by adding lepton-universality-violating new physics contributions to the effective operators ${\cal O}_9, {\cal O}_{10}, {\cal O}^\prime_9, {\cal O}^\prime_{10}$. We analyze all the scenarios where the new physics contributes to a pair of these operators at a time. We perform a global fit to all relevant data in the $b \to s$ sector to estimate the corresponding new Wilson coefficients, $C_9^{\rm NP}, C_{10}^{\rm NP}, C_9^\prime, C_{10}^\prime$. In the light of the new data on $R_K$ and $R_{K^*}$ presented in Moriond 2019, we find that the scenarios with new physics contributions to the ($C_9^{\rm NP}$, $C_9^\prime$) or ($C_9^{\rm NP}$, $C_{10}^\prime$) pair remain the most favored ones. On the other hand, though the competing scenario ($C_9^{\rm NP}$, $C_{10}^{\rm NP}$) remains attractive, its advantage above the SM reduces significantly due to the tension that emerges between the $R_K$ and $R_{K^*}$ measurements with the new data. The movement of the $R_K$ measurement towards unity would also result in the re-emergence of the one-parameter scenario $C_9^{\rm NP} = -C_9^\prime$.
[ { "created": "Fri, 22 Mar 2019 17:25:12 GMT", "version": "v1" }, { "created": "Sat, 22 Jun 2019 09:35:52 GMT", "version": "v2" }, { "created": "Wed, 24 Mar 2021 16:02:39 GMT", "version": "v3" } ]
2021-03-25
[ [ "Alok", "Ashutosh Kumar", "" ], [ "Dighe", "Amol", "" ], [ "Gangal", "Shireen", "" ], [ "Kumar", "Dinesh", "" ] ]
The anomalies in the measurements of observables involving $b \to s \mu\mu$ decays, namely $R_K$, $R_{K^*}$, $P_5^{\prime}$, and $B_s^\phi$, may be addressed by adding lepton-universality-violating new physics contributions to the effective operators ${\cal O}_9, {\cal O}_{10}, {\cal O}^\prime_9, {\cal O}^\prime_{10}$. We analyze all the scenarios where the new physics contributes to a pair of these operators at a time. We perform a global fit to all relevant data in the $b \to s$ sector to estimate the corresponding new Wilson coefficients, $C_9^{\rm NP}, C_{10}^{\rm NP}, C_9^\prime, C_{10}^\prime$. In the light of the new data on $R_K$ and $R_{K^*}$ presented in Moriond 2019, we find that the scenarios with new physics contributions to the ($C_9^{\rm NP}$, $C_9^\prime$) or ($C_9^{\rm NP}$, $C_{10}^\prime$) pair remain the most favored ones. On the other hand, though the competing scenario ($C_9^{\rm NP}$, $C_{10}^{\rm NP}$) remains attractive, its advantage above the SM reduces significantly due to the tension that emerges between the $R_K$ and $R_{K^*}$ measurements with the new data. The movement of the $R_K$ measurement towards unity would also result in the re-emergence of the one-parameter scenario $C_9^{\rm NP} = -C_9^\prime$.
1710.11142
Thomas Flacke
Giacomo Cacciapaglia (Lyon, IPN), Gabriele Ferretti (Chalmers U. Tech.), Thomas Flacke (IBS, Daejeon) and Hugo Serodio (Lund U.)
Revealing timid pseudo-scalars with taus at the LHC
5 pages, 4 figures, 2 tables. Additional material starting at page 6 after the reference list. v2: References added, typos fixed, comparison of di-tau and di-photon projected reach included in additional material. v3: discussion of systematic uncertainties and lepton isolation criteria expanded, figure 3 added, version agrees with published article
Eur.Phys.J. C78 (2018) no.9, 724
10.1140/epjc/s10052-018-6183-4
CTPU-17-35, LU TP 17-34, LYCEN 2017-07
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A light pseudo-scalar that is copiously produced at the LHC may still be allowed by present searches. While masses above 65 GeV are effectively covered by di-photon searches, the lower mass window can be tested by a new search for boosted di-tau resonances. We test this strategy on a set of composite Higgs models with top partial compositeness, where most models can be probed with an integrated luminosity below 300 fb$^{-1}$.
[ { "created": "Mon, 30 Oct 2017 18:00:07 GMT", "version": "v1" }, { "created": "Sun, 3 Dec 2017 09:06:36 GMT", "version": "v2" }, { "created": "Fri, 14 Sep 2018 09:41:31 GMT", "version": "v3" } ]
2018-09-17
[ [ "Cacciapaglia", "Giacomo", "", "Lyon, IPN" ], [ "Ferretti", "Gabriele", "", "Chalmers U.\n Tech." ], [ "Flacke", "Thomas", "", "IBS, Daejeon" ], [ "Serodio", "Hugo", "", "Lund U." ] ]
A light pseudo-scalar that is copiously produced at the LHC may still be allowed by present searches. While masses above 65 GeV are effectively covered by di-photon searches, the lower mass window can be tested by a new search for boosted di-tau resonances. We test this strategy on a set of composite Higgs models with top partial compositeness, where most models can be probed with an integrated luminosity below 300 fb$^{-1}$.
hep-ph/0605290
Masafumi Kurachi
Masafumi Kurachi, Robert Shrock
Study of the Change from Walking to Non-Walking Behavior in a Vectorial Gauge Theory as a Function of Nf
11 pages, 7 figures
JHEP0612:034,2006
10.1088/1126-6708/2006/12/034
YITP-SB-06-12
hep-ph
null
We study a vectorial gauge theory with gauge group SU(Nc) and a variable number, Nf, of massless fermions in the fundamental representation of this group. Using approximate solutions of Schwinger-Dyson and Bethe-Salpeter equations, we calculate meson masses and investigate how these depend on Nf. We focus on the range of Nf extending from near the boundary with a non-Abelian Coulomb phase, where the theory exhibits a slowly running ("walking") gauge coupling, toward smaller values where the theory has non-walking behavior. Our results include determinations of the masses of the lowest-lying flavor-adjoint mesons with J^{PC} = 0^{-+}, 1^{--}, 0^{++}, and 1^{++} (the generalized \pi, \rho, a0, and a1). Related results are given for flavor-singlet mesons and for the generalization of f_\pi. These results give insight into the change from walking to non-walking behavior in a gauge theory, as a function of Nf .
[ { "created": "Fri, 26 May 2006 17:18:04 GMT", "version": "v1" }, { "created": "Mon, 29 May 2006 17:00:41 GMT", "version": "v2" } ]
2009-11-11
[ [ "Kurachi", "Masafumi", "" ], [ "Shrock", "Robert", "" ] ]
We study a vectorial gauge theory with gauge group SU(Nc) and a variable number, Nf, of massless fermions in the fundamental representation of this group. Using approximate solutions of Schwinger-Dyson and Bethe-Salpeter equations, we calculate meson masses and investigate how these depend on Nf. We focus on the range of Nf extending from near the boundary with a non-Abelian Coulomb phase, where the theory exhibits a slowly running ("walking") gauge coupling, toward smaller values where the theory has non-walking behavior. Our results include determinations of the masses of the lowest-lying flavor-adjoint mesons with J^{PC} = 0^{-+}, 1^{--}, 0^{++}, and 1^{++} (the generalized \pi, \rho, a0, and a1). Related results are given for flavor-singlet mesons and for the generalization of f_\pi. These results give insight into the change from walking to non-walking behavior in a gauge theory, as a function of Nf .
hep-ph/9610256
Mustafa Savci
T. M. Aliev, A. Ozpineci and M. Savci (Middle East Technical University-Ankara-Turkey)
Excited Heavy Mesons Decay Formfactors in Light Cone QCD
14 pages, 2 figures, LaTeX formatted. METU-PHYS-HEP-96-22
Phys.Lett. B422 (1998) 257-264
10.1016/S0370-2693(98)00059-8
null
hep-ph
null
The formfactors of B_1 -> pi and D_1 -> pi transitions, where B_1(D_1) is the 1^+ P-wave -> Q gamma_{\nu}\gamma_5q meson state, are calculated in the framework of the light cone QCD. Furthermore these formfactors are compared with the pole dominance model prediction using the values of the strong coupling constants g_{B_1 B^* pi} and g_{D_1 D^* pi}, and a good agreement between these two different descriptions is observed.
[ { "created": "Sat, 5 Oct 1996 13:52:10 GMT", "version": "v1" }, { "created": "Thu, 2 Jan 1997 00:15:52 GMT", "version": "v2" } ]
2009-10-28
[ [ "Aliev", "T. M.", "", "Middle East Technical\n University-Ankara-Turkey" ], [ "Ozpineci", "A.", "", "Middle East Technical\n University-Ankara-Turkey" ], [ "Savci", "M.", "", "Middle East Technical\n University-Ankara-Turkey" ] ]
The formfactors of B_1 -> pi and D_1 -> pi transitions, where B_1(D_1) is the 1^+ P-wave -> Q gamma_{\nu}\gamma_5q meson state, are calculated in the framework of the light cone QCD. Furthermore these formfactors are compared with the pole dominance model prediction using the values of the strong coupling constants g_{B_1 B^* pi} and g_{D_1 D^* pi}, and a good agreement between these two different descriptions is observed.
0803.2962
Ulrich Ellwanger
U. Ellwanger, C.-C. Jean-Louis, A.M. Teixeira
Phenomenology of the General NMSSM with Gauge Mediated Supersymmetry Breaking
24 pages, 6 figures, typos corrected, reference added
JHEP0805:044,2008
10.1088/1126-6708/2008/05/044
LPT Orsay 08-34
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate various classes of Gauge Mediated Supersymmetry Breaking models and show that the Next-to-Minimal Supersymmetric Standard Model can solve the mu-problem in a phenomenologically acceptable way. These models include scenarios with singlet tadpole terms, which are phenomenologically viable, e.g., in the presence of a small Yukawa coupling <~ 10^{-5}. Scenarios with suppressed trilinear A-terms at the messenger scale lead naturally to light CP-odd scalars, which play the r\^ole of pseudo R-axions. A wide range of parameters of such models satisfies LEP constraints, with CP-even Higgs scalars below 114 GeV decaying dominantly into a pair of CP-odd scalars.
[ { "created": "Thu, 20 Mar 2008 10:46:40 GMT", "version": "v1" }, { "created": "Wed, 2 Apr 2008 16:15:38 GMT", "version": "v2" } ]
2008-11-26
[ [ "Ellwanger", "U.", "" ], [ "Jean-Louis", "C. -C.", "" ], [ "Teixeira", "A. M.", "" ] ]
We investigate various classes of Gauge Mediated Supersymmetry Breaking models and show that the Next-to-Minimal Supersymmetric Standard Model can solve the mu-problem in a phenomenologically acceptable way. These models include scenarios with singlet tadpole terms, which are phenomenologically viable, e.g., in the presence of a small Yukawa coupling <~ 10^{-5}. Scenarios with suppressed trilinear A-terms at the messenger scale lead naturally to light CP-odd scalars, which play the r\^ole of pseudo R-axions. A wide range of parameters of such models satisfies LEP constraints, with CP-even Higgs scalars below 114 GeV decaying dominantly into a pair of CP-odd scalars.
1210.3432
Peng Sun
Peng Sun, C.-P. Yuan and Feng Yuan
Heavy Quarkonium Production at Low Pt in NRQCD with Soft Gluon Resummation
18 pages, 4 figures
null
10.1103/PhysRevD.88.054008
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We extend the non-relativistic QCD (NRQCD) prediction for the production of heavy quarkonium with low transverse momentum in hadronic collisions by taking into account effects from all order soft gluon resummation. Following the Collins-Soper-Sterman formalism, we resum the most singular terms in the partonic subprocesses. The theoretical predictions of $J/\psi$ and $\Upsilon$ productions are compared to the experimental data from the fixed target experiments (E866) and the collider experiments (RHIC, Tevatron, LHC). The associated non-perturbative Sudakov form factor for the gluon distributions is found to be different from the previous assumption of rescaling the quark form factor by the ratio of color factors. This conclusion should be further checked by future experiments on Higgs boson and/or di-photon production in $pp$ collisions. We also comment on the implication of our results on determining the color-octet matrix elements associated with the $J/\psi$ and $\Upsilon$ productions in the NRQCD factorization formalism.
[ { "created": "Fri, 12 Oct 2012 05:25:18 GMT", "version": "v1" }, { "created": "Tue, 16 Apr 2013 07:20:23 GMT", "version": "v2" } ]
2013-09-11
[ [ "Sun", "Peng", "" ], [ "Yuan", "C. -P.", "" ], [ "Yuan", "Feng", "" ] ]
We extend the non-relativistic QCD (NRQCD) prediction for the production of heavy quarkonium with low transverse momentum in hadronic collisions by taking into account effects from all order soft gluon resummation. Following the Collins-Soper-Sterman formalism, we resum the most singular terms in the partonic subprocesses. The theoretical predictions of $J/\psi$ and $\Upsilon$ productions are compared to the experimental data from the fixed target experiments (E866) and the collider experiments (RHIC, Tevatron, LHC). The associated non-perturbative Sudakov form factor for the gluon distributions is found to be different from the previous assumption of rescaling the quark form factor by the ratio of color factors. This conclusion should be further checked by future experiments on Higgs boson and/or di-photon production in $pp$ collisions. We also comment on the implication of our results on determining the color-octet matrix elements associated with the $J/\psi$ and $\Upsilon$ productions in the NRQCD factorization formalism.
hep-ph/0411086
Andreas Gerhold
Andreas Gerhold
Resummed one-loop gluonic contributions to the color superconducting color charge density vanish
9 pages, 3 figures, REVTeX4; title modified, comments about gauge independence added, accepted for publication in Phys. Rev. D
Phys.Rev. D71 (2005) 014039
10.1103/PhysRevD.71.014039
TUW-04-34
hep-ph
null
It is shown that gluonic corrections to the tadpole diagrams vanish in the 2SC and CFL phases at the order where one might have expected NLO corrections. This implies that the gluonic part of the color charge density is negligible at the order of our computation. This statement remains true after inclusion of the gluon vertex correction and contributions from Nambu-Goldstone bosons.
[ { "created": "Fri, 5 Nov 2004 17:42:13 GMT", "version": "v1" }, { "created": "Thu, 20 Jan 2005 09:48:08 GMT", "version": "v2" } ]
2009-11-10
[ [ "Gerhold", "Andreas", "" ] ]
It is shown that gluonic corrections to the tadpole diagrams vanish in the 2SC and CFL phases at the order where one might have expected NLO corrections. This implies that the gluonic part of the color charge density is negligible at the order of our computation. This statement remains true after inclusion of the gluon vertex correction and contributions from Nambu-Goldstone bosons.
1806.05315
Hong-Shi Zong
Qingwu. Wang, Yonghui. Xiq and Hongshi. Zong
Nambu Jona Lasinio model with proper time regularization in a finite volume
null
null
10.1142/S0217732318502322
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Based on the two flavor NJL model with a proper time regularization, we used stationary wave condition (SWC) for the first time to study the influence of the finite volume effects on the chiral phase transition of quark matter at finite temperature. It is found that when the cubic volume size L is large than LSWC = 500 fm, the chiral quark condensate is indistinguishable from that max at L = $\infinity$,Here it should be noted that 500 fm is far greater than the size of QGP produced at laboratory and the lattice QCD simulation space size. It is also much larger than the previous limit size LAPBC = 5 fm estimated by the commonly used anti-periodic boundary condition (APBC). max We also found that when the space size L is less than LSWC = 0.25 fm, the spontaneous symmetry min breaking concept is no longer valid. In addition, we first introduce the spatial susceptibility, and through the study of the spatial susceptibility, it was revealed for the first time that the chiral phase transition caused by the finite volume effects in the nonchiral limit is a crossover.
[ { "created": "Thu, 14 Jun 2018 00:49:07 GMT", "version": "v1" } ]
2019-01-30
[ [ "Wang", "Qingwu.", "" ], [ "Xiq", "Yonghui.", "" ], [ "Zong", "Hongshi.", "" ] ]
Based on the two flavor NJL model with a proper time regularization, we used stationary wave condition (SWC) for the first time to study the influence of the finite volume effects on the chiral phase transition of quark matter at finite temperature. It is found that when the cubic volume size L is large than LSWC = 500 fm, the chiral quark condensate is indistinguishable from that max at L = $\infinity$,Here it should be noted that 500 fm is far greater than the size of QGP produced at laboratory and the lattice QCD simulation space size. It is also much larger than the previous limit size LAPBC = 5 fm estimated by the commonly used anti-periodic boundary condition (APBC). max We also found that when the space size L is less than LSWC = 0.25 fm, the spontaneous symmetry min breaking concept is no longer valid. In addition, we first introduce the spatial susceptibility, and through the study of the spatial susceptibility, it was revealed for the first time that the chiral phase transition caused by the finite volume effects in the nonchiral limit is a crossover.
2405.12285
Shuailiang Ge
Haipeng An, Shuailiang Ge, Jia Liu, Mingzhe Liu
In-situ Measurements of Dark Photon Dark Matter using Parker Solar Probe: Going beyond the Radio Window
13 pages, 6 figures
null
null
null
hep-ph astro-ph.CO astro-ph.IM astro-ph.SR hep-ex physics.space-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Dark photon dark matter emerges as a compelling candidate for ultralight bosonic dark matter, detectable through resonant conversion into photons within a plasma environment. This study employs in-situ measurements from the Parker Solar Probe (PSP), the first spacecraft to venture into the solar corona, to probe for DPDM signatures. The PSP in-situ measurements go beyond the traditional radio window, spanning frequencies between about 10 kHz and 20 MHz, a challenging range inaccessible to Earth-based radio astronomy. Additionally, the proximity of PSP to the resonant conversion location enhances the signal flux, providing a distinct advantage over ground-based observations. As a result, the PSP data establishes the most stringent constraints on the kinetic mixing parameter $\epsilon$ for DPDM frequencies between 70 kHz and 20 MHz, with values of $\epsilon \lesssim 10^{-14}-10^{-13}$. Investigating the data from STEREO satellites resulted in weaker constraints compared to those obtained from PSP. By utilizing state-of-the-art solar observations from space, we have surpassed the cosmic microwave background limits established in the early universe.
[ { "created": "Mon, 20 May 2024 18:00:03 GMT", "version": "v1" } ]
2024-05-22
[ [ "An", "Haipeng", "" ], [ "Ge", "Shuailiang", "" ], [ "Liu", "Jia", "" ], [ "Liu", "Mingzhe", "" ] ]
Dark photon dark matter emerges as a compelling candidate for ultralight bosonic dark matter, detectable through resonant conversion into photons within a plasma environment. This study employs in-situ measurements from the Parker Solar Probe (PSP), the first spacecraft to venture into the solar corona, to probe for DPDM signatures. The PSP in-situ measurements go beyond the traditional radio window, spanning frequencies between about 10 kHz and 20 MHz, a challenging range inaccessible to Earth-based radio astronomy. Additionally, the proximity of PSP to the resonant conversion location enhances the signal flux, providing a distinct advantage over ground-based observations. As a result, the PSP data establishes the most stringent constraints on the kinetic mixing parameter $\epsilon$ for DPDM frequencies between 70 kHz and 20 MHz, with values of $\epsilon \lesssim 10^{-14}-10^{-13}$. Investigating the data from STEREO satellites resulted in weaker constraints compared to those obtained from PSP. By utilizing state-of-the-art solar observations from space, we have surpassed the cosmic microwave background limits established in the early universe.
hep-ph/9705351
null
S. Esposito and N. Tancredi (I.N.F.N. Sezione di Napoli)
Pontecorvo neutrino-antineutrino oscillations: theory and experimental limits
11 pages, Latex2e
Mod.Phys.Lett.A12:1829-1838,1997
10.1142/S0217732397001862
DSF-97/6 , INFN-NA-IV-97/6
hep-ph astro-ph
null
We study Pontecorvo neutrino-antineutrino oscillations both in vacuum and in matter within a field theoretic approach, showing that this phenomenon can occur only if neutrinos have a Dirac-Majorana mass term. We find that matter effects suppress these oscillations and cannot explain the solar neutrino problem. On the contrary, a vacuum neutrino-antineutrino oscillations solution to this problem exists. We analyze this solution and available data from laboratory experiments giving stringent limits on $\nu_e$ and $\nu_{\mu}$ Majorana masses.
[ { "created": "Mon, 19 May 1997 07:40:21 GMT", "version": "v1" } ]
2008-11-26
[ [ "Esposito", "S.", "", "I.N.F.N. Sezione di Napoli" ], [ "Tancredi", "N.", "", "I.N.F.N. Sezione di Napoli" ] ]
We study Pontecorvo neutrino-antineutrino oscillations both in vacuum and in matter within a field theoretic approach, showing that this phenomenon can occur only if neutrinos have a Dirac-Majorana mass term. We find that matter effects suppress these oscillations and cannot explain the solar neutrino problem. On the contrary, a vacuum neutrino-antineutrino oscillations solution to this problem exists. We analyze this solution and available data from laboratory experiments giving stringent limits on $\nu_e$ and $\nu_{\mu}$ Majorana masses.
0806.3674
Pedro Schwaller
A. Freitas, P. Schwaller, D. Wyler
Consequences of T-parity breaking in the Littlest Higgs model
30 pages
JHEP 0809:013,2008
10.1088/1126-6708/2008/09/013
ZU-TH 08/08
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper we consider the effects of the T-parity violating anomalous Wess-Zumino-Witten-Term in the Littlest Higgs model. Apart from tree level processes, the loop induced decays of the heavy mirror particles into light standard model fermions lead to a new and rich phenomenology in particular at breaking scales f below 1 TeV. Various processes are calculated and their signatures at present and future colliders are discussed. As a byproduct we find an alternative production mechanism for the Higgs boson.
[ { "created": "Mon, 23 Jun 2008 13:12:15 GMT", "version": "v1" } ]
2009-03-12
[ [ "Freitas", "A.", "" ], [ "Schwaller", "P.", "" ], [ "Wyler", "D.", "" ] ]
In this paper we consider the effects of the T-parity violating anomalous Wess-Zumino-Witten-Term in the Littlest Higgs model. Apart from tree level processes, the loop induced decays of the heavy mirror particles into light standard model fermions lead to a new and rich phenomenology in particular at breaking scales f below 1 TeV. Various processes are calculated and their signatures at present and future colliders are discussed. As a byproduct we find an alternative production mechanism for the Higgs boson.
1309.3976
Ludwig Greil
Peter C. Bruns, Ludwig Greil, Andreas Sch\"afer
Chiral behavior of vector meson self energies
null
Phys. Rev. D 88, 114503 (2013)
10.1103/PhysRevD.88.114503
null
hep-ph hep-lat
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We employ a chiral Lagrangian framework with three dynamical flavors to calculate the masses of the lowest-lying vector mesons to one loop accuracy, and use the resulting formulae to extrapolate recent QCDSF lattice data on vector meson masses and mass ratios to the physical point. Our representation for the vector meson self energies also enables us to discuss loop corrections to the $\omega\phi$ mixing amplitude.
[ { "created": "Mon, 16 Sep 2013 14:30:28 GMT", "version": "v1" } ]
2013-12-16
[ [ "Bruns", "Peter C.", "" ], [ "Greil", "Ludwig", "" ], [ "Schäfer", "Andreas", "" ] ]
We employ a chiral Lagrangian framework with three dynamical flavors to calculate the masses of the lowest-lying vector mesons to one loop accuracy, and use the resulting formulae to extrapolate recent QCDSF lattice data on vector meson masses and mass ratios to the physical point. Our representation for the vector meson self energies also enables us to discuss loop corrections to the $\omega\phi$ mixing amplitude.
2403.13991
Umer Zubair
Umer Zubair
Smooth $\mu$-Hybrid and Non-Minimal Higgs Inflation in $SU(4)_{C}\times SU(2)_{L}\times SU(2)_{R}$ With Observable Gravitational Waves
30 pages, 9 figures
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose to study a smooth variant of the $\mu$-hybrid inflation model and a non-minimal Higgs model of inflation with quartic non-minimal coupling between the Higgs field and gravity within the context of a realistic GUT gauge group based on supersymmetric $SU(4)_{C}\times SU(2)_{L}\times SU(2)_{R}$. These models are incorporated with a realistic scenario of reheating and non-thermal leptogenesis, compatible with the constraints from the baryon asymmetry of the universe. Notably, both models successfully address the MSSM $\mu$-problem and avoid the issue of primordial magnetic monopoles. Our analysis reveals that both models predict a scalar spectral index $n_s$ that closely aligns with the central observationally favored value of Planck2018 + BICEP2/Keck Array (BK15) data and yield a large tensor-to-scalar ratio ($r > 10^{-3}$), potentially detectable in forthcoming CMB experiments.
[ { "created": "Wed, 20 Mar 2024 21:43:05 GMT", "version": "v1" } ]
2024-03-22
[ [ "Zubair", "Umer", "" ] ]
We propose to study a smooth variant of the $\mu$-hybrid inflation model and a non-minimal Higgs model of inflation with quartic non-minimal coupling between the Higgs field and gravity within the context of a realistic GUT gauge group based on supersymmetric $SU(4)_{C}\times SU(2)_{L}\times SU(2)_{R}$. These models are incorporated with a realistic scenario of reheating and non-thermal leptogenesis, compatible with the constraints from the baryon asymmetry of the universe. Notably, both models successfully address the MSSM $\mu$-problem and avoid the issue of primordial magnetic monopoles. Our analysis reveals that both models predict a scalar spectral index $n_s$ that closely aligns with the central observationally favored value of Planck2018 + BICEP2/Keck Array (BK15) data and yield a large tensor-to-scalar ratio ($r > 10^{-3}$), potentially detectable in forthcoming CMB experiments.
hep-ph/9511409
Matthias Neubert
Matthias Neubert (CERN)
Heavy Flavour Physics
27 pages, 7 figures, discussion of the theory of the B semileptonic branching ratio has been revised
null
null
CERN-TH/95-307
hep-ph
null
The current status of the theory and phenomenology of weak decays of hadrons containing a heavy quark is reviewed. Exclusive semileptonic and rare decays of $B$ mesons are discussed, as well as inclusive decay rates, the semileptonic branching ratio of the $B$ meson, and the lifetimes of $b$-flavoured hadrons. Determinations of $\alpha_s$ from $\Upsilon$ spectroscopy are briefly presented.
[ { "created": "Fri, 24 Nov 1995 16:23:11 GMT", "version": "v1" }, { "created": "Wed, 20 Dec 1995 18:33:19 GMT", "version": "v2" } ]
2008-02-03
[ [ "Neubert", "Matthias", "", "CERN" ] ]
The current status of the theory and phenomenology of weak decays of hadrons containing a heavy quark is reviewed. Exclusive semileptonic and rare decays of $B$ mesons are discussed, as well as inclusive decay rates, the semileptonic branching ratio of the $B$ meson, and the lifetimes of $b$-flavoured hadrons. Determinations of $\alpha_s$ from $\Upsilon$ spectroscopy are briefly presented.
1008.4272
Boris Kopeliovich
B. Z. Kopeliovich, I. K. Potashnikova, H. J. Pirner, Ivan Schmidt
Heavy quarkonium production: Nontrivial transition from pA to AA collisions
10 pages 8 figures. The accuracy of calculations is improved
Phys.Rev.C83:014912,2011
10.1103/PhysRevC.83.014912
USM-TH-271
hep-ph nucl-ex nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Two novel QCD effects, double color filtering and mutual boosting of the saturation scales in colliding nuclei, affect the transparency of the nuclei for quark dipoles in comparison with proton-nucleus collisions. The former effect increases the survival probability of the dipoles, since color filtering in one nucleus makes the other one more transparent. The second effect acts in the opposite direction and is stronger, it makes the colliding nuclei more opaque than in the case of pA collisions. As a result of parton saturation in nuclei the effective scale is shifted upwards, what leads to an increase of the gluon density at small x. This in turn leads to a stronger transverse momentum broadening in AA compared with pA collisions, i.e. to an additional growth of the saturation momentum. Such a mutual boosting leads to a system of reciprocity equations, which result in a saturation scale, a few times higher in AA than in pA collisions at the energies of LHC. Since the dipole cross section is proportional to the saturation momentum squared, the nuclei become much more opaque for dipoles in AA than in pA collisions. For the same reason gluon shadowing turns out to be boosted to a larger magnitude compared with the product of the gluon shadowing factors in each of the colliding nuclei. All these effects make it more difficult to establish a baseline for anomalous J/Psi suppression in heavy ion collisions at high energies.
[ { "created": "Wed, 25 Aug 2010 13:31:22 GMT", "version": "v1" }, { "created": "Sun, 19 Dec 2010 23:35:37 GMT", "version": "v2" } ]
2011-02-18
[ [ "Kopeliovich", "B. Z.", "" ], [ "Potashnikova", "I. K.", "" ], [ "Pirner", "H. J.", "" ], [ "Schmidt", "Ivan", "" ] ]
Two novel QCD effects, double color filtering and mutual boosting of the saturation scales in colliding nuclei, affect the transparency of the nuclei for quark dipoles in comparison with proton-nucleus collisions. The former effect increases the survival probability of the dipoles, since color filtering in one nucleus makes the other one more transparent. The second effect acts in the opposite direction and is stronger, it makes the colliding nuclei more opaque than in the case of pA collisions. As a result of parton saturation in nuclei the effective scale is shifted upwards, what leads to an increase of the gluon density at small x. This in turn leads to a stronger transverse momentum broadening in AA compared with pA collisions, i.e. to an additional growth of the saturation momentum. Such a mutual boosting leads to a system of reciprocity equations, which result in a saturation scale, a few times higher in AA than in pA collisions at the energies of LHC. Since the dipole cross section is proportional to the saturation momentum squared, the nuclei become much more opaque for dipoles in AA than in pA collisions. For the same reason gluon shadowing turns out to be boosted to a larger magnitude compared with the product of the gluon shadowing factors in each of the colliding nuclei. All these effects make it more difficult to establish a baseline for anomalous J/Psi suppression in heavy ion collisions at high energies.
hep-ph/9803232
Alexandr Andrianov
A. A. Andrianov, D. Espriu and R.Tarrach (Universitat de Barcelona)
The Extended Chiral Quark Model and QCD
43 pages, Sec.7 is slightly corrected, fit and conclusions are unchanged
Nucl.Phys. B533 (1998) 429-472
10.1016/S0550-3213(98)00508-2
UB-ECM-PF 98/04
hep-ph
null
We consider the low energy effective action of QCD below the chiral symmetry breaking scale, including, in Wilson's spirit, all operators of dimensionality less or equal to 6 which can be built with quark and chiral fields. The effect of the residual gluon interactions is contained in a number of coupling constants, whose running is studied. The resulting model is an extension of both the chiral quark model and the Nambu-Jona-Lasinio one. Constraints on the coefficients of the effective lagrangian are derived from the requirement of chiral symmetry restoration at energies above the chiral symmetry breaking scale, from matching to QCD at intermediate scales, and by fitting some hadronic observables. In this model two types of pseudoscalar states (massless pions and massive \Pi-mesons), as well as one scalar one arise as a consequence of dynamical chiral symmetry breaking. Their masses and coupling constants are studied. We also predict a number of low energy structural constants. We find out that QCD favours a low-energy effective theory which is largely dominated by the simplest chiral quark model, whereas higher dimensional operators (such as those of the Nambu-Jona-Lasinio type) can be assumed to be small.
[ { "created": "Tue, 3 Mar 1998 18:24:27 GMT", "version": "v1" }, { "created": "Wed, 25 Mar 1998 21:03:50 GMT", "version": "v2" }, { "created": "Wed, 29 Apr 1998 19:06:07 GMT", "version": "v3" } ]
2009-10-31
[ [ "Andrianov", "A. A.", "", "Universitat de Barcelona" ], [ "Espriu", "D.", "", "Universitat de Barcelona" ], [ "Tarrach", "R.", "", "Universitat de Barcelona" ] ]
We consider the low energy effective action of QCD below the chiral symmetry breaking scale, including, in Wilson's spirit, all operators of dimensionality less or equal to 6 which can be built with quark and chiral fields. The effect of the residual gluon interactions is contained in a number of coupling constants, whose running is studied. The resulting model is an extension of both the chiral quark model and the Nambu-Jona-Lasinio one. Constraints on the coefficients of the effective lagrangian are derived from the requirement of chiral symmetry restoration at energies above the chiral symmetry breaking scale, from matching to QCD at intermediate scales, and by fitting some hadronic observables. In this model two types of pseudoscalar states (massless pions and massive \Pi-mesons), as well as one scalar one arise as a consequence of dynamical chiral symmetry breaking. Their masses and coupling constants are studied. We also predict a number of low energy structural constants. We find out that QCD favours a low-energy effective theory which is largely dominated by the simplest chiral quark model, whereas higher dimensional operators (such as those of the Nambu-Jona-Lasinio type) can be assumed to be small.
hep-ph/0505190
Masataka Okamoto
Masataka Okamoto
B, D, K decays and CKM matrix from lattice QCD
4 pages, 2 figures. Contribution to the XXXXth Rencontres de Moriond, "QCD and High Energy Hadronic Interactions", La Thuile, March 2005
null
null
null
hep-ph hep-ex
null
We use lattice QCD to fully determine the CKM matrix. |V_{cd}|, |V_{cs}|, |V_{ub}|, |V_{cb}| and |V_{us}| are, respectively, directly determined with recent lattice results for form factors of semileptonic D->pi l nu, D->K l nu, B->pi l nu, B->D l nu and K->pi l nu decays obtained by the Fermilab Lattice, MILC, and HPQCD Collaborations. In addition, |V_{ud}|, |V_{tb}|, |V_{ts}| and |V_{td}| are determined by using unitarity of the CKM matrix and the experimental result for sin(2beta).
[ { "created": "Mon, 23 May 2005 04:30:03 GMT", "version": "v1" } ]
2007-05-23
[ [ "Okamoto", "Masataka", "" ] ]
We use lattice QCD to fully determine the CKM matrix. |V_{cd}|, |V_{cs}|, |V_{ub}|, |V_{cb}| and |V_{us}| are, respectively, directly determined with recent lattice results for form factors of semileptonic D->pi l nu, D->K l nu, B->pi l nu, B->D l nu and K->pi l nu decays obtained by the Fermilab Lattice, MILC, and HPQCD Collaborations. In addition, |V_{ud}|, |V_{tb}|, |V_{ts}| and |V_{td}| are determined by using unitarity of the CKM matrix and the experimental result for sin(2beta).
2309.14310
Mohamed Abu-Shady
M. Abu-shady and H. M. Fath-Allah
Properties and Behaviors of Heavy Quarkonia: Insights Through Fractional Model and Topological Defects
29 pages, 13 figures, 6 Tables
null
null
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
In this study, we investigated the impact of a topological defect on the properties of heavy quarkonia using the extended Cornell potential. We solved the fractional radial Schrodinger equation (SE) using the extended Nikorov-Uvarov (ENU) method to obtain the eigen energy, which allowed us to calculate the masses of charmonium and bottomonium. One significant observation was the splitting between np and nd states, which we attributed to the presence of the topological defect. We discovered that the excited states were divided into components corresponding to 2l + 1, indicating that the gravity field induced by the topological defect interacts with energy levels in a manner similar to the Zeeman effect caused by a magnetic field. Additionally, we derived the wave function and calculated the root mean radii for charmonium and bottomonium. A comparison with classical models was performed, resulting in better results being obtained. Furthermore, we investigated the thermodynamic properties of charmonium and bottomonium, determining quantities such as energy, partition function, free energy, mean energy, and specific heat for p-states. The obtained results were found to be consistent with experimental data and previous works. In conclusion, the fractional model used in this work proved essential in understanding the various properties and behaviors of heavy quarkonia in the presence of topological defects.
[ { "created": "Sat, 26 Aug 2023 09:02:29 GMT", "version": "v1" } ]
2023-09-26
[ [ "Abu-shady", "M.", "" ], [ "Fath-Allah", "H. M.", "" ] ]
In this study, we investigated the impact of a topological defect on the properties of heavy quarkonia using the extended Cornell potential. We solved the fractional radial Schrodinger equation (SE) using the extended Nikorov-Uvarov (ENU) method to obtain the eigen energy, which allowed us to calculate the masses of charmonium and bottomonium. One significant observation was the splitting between np and nd states, which we attributed to the presence of the topological defect. We discovered that the excited states were divided into components corresponding to 2l + 1, indicating that the gravity field induced by the topological defect interacts with energy levels in a manner similar to the Zeeman effect caused by a magnetic field. Additionally, we derived the wave function and calculated the root mean radii for charmonium and bottomonium. A comparison with classical models was performed, resulting in better results being obtained. Furthermore, we investigated the thermodynamic properties of charmonium and bottomonium, determining quantities such as energy, partition function, free energy, mean energy, and specific heat for p-states. The obtained results were found to be consistent with experimental data and previous works. In conclusion, the fractional model used in this work proved essential in understanding the various properties and behaviors of heavy quarkonia in the presence of topological defects.
hep-ph/9210212
Greg Mahlon
G. Mahlon, T.M. Yan, and C. Dunn
Generalized Gluon Currents and Applications in QCD
80 pages, 2 figures (appended in pictex), CLNS 91/1120
Phys.Rev. D48 (1993) 1337-1374
10.1103/PhysRevD.48.1337
null
hep-ph
null
We consider the process containing two quark lines and an arbitrary number of gluons in a spinor helicity framework. A current with two off-shell gluons appears in the amplitude. We first study this modified gluon current using recursion relations. The recursion relation for the modified gluon current is solved for the case of like-helicity gluons. We apply the modified gluon current to compute the amplitude for $q \bar q \rightarrow q \bar q gg \cdots g$ in the like-helicity gluon case.
[ { "created": "Mon, 5 Oct 1992 18:13:55 GMT", "version": "v1" } ]
2009-10-22
[ [ "Mahlon", "G.", "" ], [ "Yan", "T. M.", "" ], [ "Dunn", "C.", "" ] ]
We consider the process containing two quark lines and an arbitrary number of gluons in a spinor helicity framework. A current with two off-shell gluons appears in the amplitude. We first study this modified gluon current using recursion relations. The recursion relation for the modified gluon current is solved for the case of like-helicity gluons. We apply the modified gluon current to compute the amplitude for $q \bar q \rightarrow q \bar q gg \cdots g$ in the like-helicity gluon case.
1407.7309
Xing-Gang Wu
Jian-Ming Shen, Xing-Gang Wu, Hong-Hao Ma and Sheng-Quan Wang
QCD corrections to the $B_c$ to charmonia semi-leptonic decays
11 pages, 5 figures
Phys. Rev. D 90, 034025 (2014)
10.1103/PhysRevD.90.034025
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a detailed analysis on the $B_c$ meson semi-leptonic decays, $B_c \to \eta_c (J/\psi) \ell \nu$, up to next-to-leading order (NLO) QCD correction. We adopt the principle of maximum conformality (PMC) to set the renormalization scales for those decays. After applying the PMC scale setting, we determine the optimal renormalization scale for the $B_c\to\eta_c(J/\psi)$ transition form factors (TFFs). Because of the same $\{\beta_0\}$-terms, the optimal PMC scales at the NLO level are the same for all those TFFs, i.e. $\mu_r^{\rm PMC} \approx 0.8{\rm GeV}$. We adopt a strong coupling model from the massive perturbation theory (MPT) to achieve a reliable pQCD estimation in this low energy region. Furthermore, we adopt a monopole form as an extrapolation for the $B_c\to\eta_c(J/\psi)$ TFFs to all their allowable $q^2$ region. Then, we predict $\Gamma_{B_c \to \eta_c \ell \nu}(\ell=e,\mu) =(71.53^{+11.27}_{-8.90})\times 10^{-15} {\rm GeV}$, $\Gamma_{B_c \to \eta_c \tau \nu}=(27.14^{+5.93}_{-4.33})\times 10^{-15} {\rm GeV}$, $\Gamma_{B_c \to J/\psi \ell \nu}(\ell=e,\mu) =(106.31^{+18.59}_{-14.01}) \times 10^{-15} {\rm GeV}$, $\Gamma_{B_c \to J/\psi \tau \nu} =(28.25^{+6.02}_{-4.35})\times 10^{-15} {\rm GeV}$, where the uncertainties are squared averages of all the mentioned error sources. We show that the present prediction of the production cross section times branching ratio for $B^+_c\to J/\psi \ell^+ v$ relative to that for $B^+ \to J/\psi K^+$, i.e. $\Re(J/\psi \ell^+ \nu)$, is in a better agreement with CDF measurements than the previous predictions.
[ { "created": "Mon, 28 Jul 2014 02:32:34 GMT", "version": "v1" } ]
2014-09-02
[ [ "Shen", "Jian-Ming", "" ], [ "Wu", "Xing-Gang", "" ], [ "Ma", "Hong-Hao", "" ], [ "Wang", "Sheng-Quan", "" ] ]
We present a detailed analysis on the $B_c$ meson semi-leptonic decays, $B_c \to \eta_c (J/\psi) \ell \nu$, up to next-to-leading order (NLO) QCD correction. We adopt the principle of maximum conformality (PMC) to set the renormalization scales for those decays. After applying the PMC scale setting, we determine the optimal renormalization scale for the $B_c\to\eta_c(J/\psi)$ transition form factors (TFFs). Because of the same $\{\beta_0\}$-terms, the optimal PMC scales at the NLO level are the same for all those TFFs, i.e. $\mu_r^{\rm PMC} \approx 0.8{\rm GeV}$. We adopt a strong coupling model from the massive perturbation theory (MPT) to achieve a reliable pQCD estimation in this low energy region. Furthermore, we adopt a monopole form as an extrapolation for the $B_c\to\eta_c(J/\psi)$ TFFs to all their allowable $q^2$ region. Then, we predict $\Gamma_{B_c \to \eta_c \ell \nu}(\ell=e,\mu) =(71.53^{+11.27}_{-8.90})\times 10^{-15} {\rm GeV}$, $\Gamma_{B_c \to \eta_c \tau \nu}=(27.14^{+5.93}_{-4.33})\times 10^{-15} {\rm GeV}$, $\Gamma_{B_c \to J/\psi \ell \nu}(\ell=e,\mu) =(106.31^{+18.59}_{-14.01}) \times 10^{-15} {\rm GeV}$, $\Gamma_{B_c \to J/\psi \tau \nu} =(28.25^{+6.02}_{-4.35})\times 10^{-15} {\rm GeV}$, where the uncertainties are squared averages of all the mentioned error sources. We show that the present prediction of the production cross section times branching ratio for $B^+_c\to J/\psi \ell^+ v$ relative to that for $B^+ \to J/\psi K^+$, i.e. $\Re(J/\psi \ell^+ \nu)$, is in a better agreement with CDF measurements than the previous predictions.
1403.3576
Valeriy Nazaruk
Valeriy Nazaruk
Optical theorem and unitarity
6 pages, 1 figure, minor changes
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It is shown that an application of optical theorem for the non-unitary S-matrix can lead to the qualitative error in the result.
[ { "created": "Fri, 14 Mar 2014 13:39:06 GMT", "version": "v1" }, { "created": "Thu, 20 Mar 2014 14:08:15 GMT", "version": "v2" } ]
2014-03-21
[ [ "Nazaruk", "Valeriy", "" ] ]
It is shown that an application of optical theorem for the non-unitary S-matrix can lead to the qualitative error in the result.
2009.02309
Volodymyr Vovchenko
Volodymyr Vovchenko, Bastian B. Brandt, Francesca Cuteri, Gergely Endr\H{o}di, Fazlollah Hajkarim, J\"urgen Schaffner-Bielich
Pion condensation in the early Universe at nonvanishing lepton flavor asymmetry and its gravitational wave signatures
6 pages main text + 5 pages supplementary material, contains ancillary files with figure data, to appear in Physical Review Letters
Phys. Rev. Lett. 126, 012701 (2021)
10.1103/PhysRevLett.126.012701
null
hep-ph astro-ph.CO hep-lat
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate the possible formation of a Bose-Einstein condensed phase of pions in the early Universe at nonvanishing values of lepton flavor asymmetries. A hadron resonance gas model with pion interactions, based on first-principle lattice QCD simulations at nonzero isospin density, is used to evaluate cosmic trajectories at various values of electron, muon, and tau lepton asymmetries that satisfy the available constraints on the total lepton asymmetry. The cosmic trajectory can pass through the pion condensed phase if the combined electron and muon asymmetry is sufficiently large: $|l_e + l_{\mu}| \gtrsim 0.1$, with little sensitivity to the difference $l_e - l_\mu$ between the individual flavor asymmetries. Future constraints on the values of the individual lepton flavor asymmetries will thus be able to either confirm or rule out the condensation of pions during the cosmic QCD epoch. We demonstrate that the pion condensed phase leaves an imprint both on the spectrum of primordial gravitational waves and on the mass distribution of primordial black holes at the QCD scale e.g. the black hole binary of recent LIGO event GW190521 can be formed in that phase.
[ { "created": "Fri, 4 Sep 2020 17:18:10 GMT", "version": "v1" }, { "created": "Tue, 22 Dec 2020 04:02:29 GMT", "version": "v2" } ]
2021-01-08
[ [ "Vovchenko", "Volodymyr", "" ], [ "Brandt", "Bastian B.", "" ], [ "Cuteri", "Francesca", "" ], [ "Endrődi", "Gergely", "" ], [ "Hajkarim", "Fazlollah", "" ], [ "Schaffner-Bielich", "Jürgen", "" ] ]
We investigate the possible formation of a Bose-Einstein condensed phase of pions in the early Universe at nonvanishing values of lepton flavor asymmetries. A hadron resonance gas model with pion interactions, based on first-principle lattice QCD simulations at nonzero isospin density, is used to evaluate cosmic trajectories at various values of electron, muon, and tau lepton asymmetries that satisfy the available constraints on the total lepton asymmetry. The cosmic trajectory can pass through the pion condensed phase if the combined electron and muon asymmetry is sufficiently large: $|l_e + l_{\mu}| \gtrsim 0.1$, with little sensitivity to the difference $l_e - l_\mu$ between the individual flavor asymmetries. Future constraints on the values of the individual lepton flavor asymmetries will thus be able to either confirm or rule out the condensation of pions during the cosmic QCD epoch. We demonstrate that the pion condensed phase leaves an imprint both on the spectrum of primordial gravitational waves and on the mass distribution of primordial black holes at the QCD scale e.g. the black hole binary of recent LIGO event GW190521 can be formed in that phase.
1905.00315
Krzysztof Jod{\l}owski
Andrzej Hryczuk, Krzysztof Jod{\l}owski, Emmanuel Moulin, Lucia Rinchiuso, Leszek Roszkowski, Enrico Maria Sessolo, Sebastian Trojanowski
Testing dark matter with Cherenkov light -- prospects of H.E.S.S. and CTA for exploring minimal supersymmetry
33 pages, 6 figures, supplemental material with CTA limits provided. Minor corrections and references added, matches published version in JHEP
JHEP 1910 (2019) 043
10.1007/JHEP10(2019)043
null
hep-ph astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We provide an updated and improved study of the prospects of the H.E.S.S. and Cherenkov Telescope Array (CTA) experiments in testing neutralino dark matter in the Minimal Supersymmetric Standard Model with nine free parameters (p9MSSM). We include all relevant experimental constraints and theoretical developments, in particular the calculation of the Sommerfeld enhancement for both present-day annihilation and the relic abundance. We perform a state-of-the-art analysis of the CTA sensitivity with a log-likelihood test ratio statistics and apply it to a numerical scan of the p9MSSM parameter space focusing on a TeV scale dark matter. We find that, assuming Einasto profile of dark matter halo in the Milky Way, H.E.S.S. has already been able to nearly reach the so-called thermal WIMP value, while CTA will go below it by providing a further improvement of at least an order of magnitude. Both H.E.S.S. and CTA are sensitive to several cases for which direct detection cross section will be below the so-called neutrino floor, with H.E.S.S. being sensitive to most of the wino region, while CTA also covering a large fraction of the ~1 TeV higgsino region. We show that CTA sensitivity will be further improved in the monochromatic photon search mode for both single-component and underabundant dark matter.
[ { "created": "Wed, 1 May 2019 13:53:06 GMT", "version": "v1" }, { "created": "Wed, 30 Oct 2019 15:08:55 GMT", "version": "v2" } ]
2019-10-31
[ [ "Hryczuk", "Andrzej", "" ], [ "Jodłowski", "Krzysztof", "" ], [ "Moulin", "Emmanuel", "" ], [ "Rinchiuso", "Lucia", "" ], [ "Roszkowski", "Leszek", "" ], [ "Sessolo", "Enrico Maria", "" ], [ "Trojanowski", "Sebastian", "" ] ]
We provide an updated and improved study of the prospects of the H.E.S.S. and Cherenkov Telescope Array (CTA) experiments in testing neutralino dark matter in the Minimal Supersymmetric Standard Model with nine free parameters (p9MSSM). We include all relevant experimental constraints and theoretical developments, in particular the calculation of the Sommerfeld enhancement for both present-day annihilation and the relic abundance. We perform a state-of-the-art analysis of the CTA sensitivity with a log-likelihood test ratio statistics and apply it to a numerical scan of the p9MSSM parameter space focusing on a TeV scale dark matter. We find that, assuming Einasto profile of dark matter halo in the Milky Way, H.E.S.S. has already been able to nearly reach the so-called thermal WIMP value, while CTA will go below it by providing a further improvement of at least an order of magnitude. Both H.E.S.S. and CTA are sensitive to several cases for which direct detection cross section will be below the so-called neutrino floor, with H.E.S.S. being sensitive to most of the wino region, while CTA also covering a large fraction of the ~1 TeV higgsino region. We show that CTA sensitivity will be further improved in the monochromatic photon search mode for both single-component and underabundant dark matter.
hep-ph/0008305
Sergei Gninenko
S.N. Gninenko, N.V. Krasnikov
Tau neutrino magnetic moments from the Super-Kamiokande and $\nu$ e-scattering data
12 pages, To appear in Phys. Lett. B
Phys.Lett. B490 (2000) 9-15
10.1016/S0370-2693(00)00954-0
null
hep-ph
null
Combined results on $\nu_{\mu}\to \nu_{\tau}$ oscillations and $\nu e$-scattering from the Super-Kamiokande and LAMPF experiments, respectively, limit the Dirac $\nu_{\tau}$ diagonal magnetic moment to $\mu_{\nu_{\tau}} < 1.9\times 10^{-9} \mu_{B}$. For the scheme with 3 Majorana neutrinos the LAMPF results allow the limitation of effective $\nu_{\tau}$ magnetic moment to $\mu_{\nu_{\tau}} < 7.6 \times 10^{-10}\mu_{B}$. The moments in the scheme with additional Majorana light sterile neutrinos as well as experiments on stimulated radiative neutrino conversion are also discussed.
[ { "created": "Tue, 29 Aug 2000 15:31:31 GMT", "version": "v1" } ]
2009-10-31
[ [ "Gninenko", "S. N.", "" ], [ "Krasnikov", "N. V.", "" ] ]
Combined results on $\nu_{\mu}\to \nu_{\tau}$ oscillations and $\nu e$-scattering from the Super-Kamiokande and LAMPF experiments, respectively, limit the Dirac $\nu_{\tau}$ diagonal magnetic moment to $\mu_{\nu_{\tau}} < 1.9\times 10^{-9} \mu_{B}$. For the scheme with 3 Majorana neutrinos the LAMPF results allow the limitation of effective $\nu_{\tau}$ magnetic moment to $\mu_{\nu_{\tau}} < 7.6 \times 10^{-10}\mu_{B}$. The moments in the scheme with additional Majorana light sterile neutrinos as well as experiments on stimulated radiative neutrino conversion are also discussed.
2104.03342
Oleg Lebedev
Oleg Lebedev
The Higgs Portal to Cosmology
115 pages. Review commissioned by Prog. Part. Nucl. Phys. Contains technicalities. v2: accepted version (typos fixed, references updated). v4: footnotes clarifying the assumption a0=1 in Sec. 8.3, 8.4 added; typos in eqs. 256 and 266 corrected; corrections to eqs. 331,333
null
10.1016/j.ppnp.2021.103881
null
hep-ph astro-ph.CO
http://creativecommons.org/licenses/by/4.0/
The discovery of the Higgs boson has opened a new avenue for exploring physics beyond the Standard Model. In this review, we discuss cosmological aspects of the simplest Higgs couplings to the hidden sector, known as the Higgs portal. We focus on implications of such couplings for inflation, vacuum stability and dark matter, with the latter including both the traditional weakly interacting massive particles as well as feebly interacting scalars. The cosmological impact of the Higgs portal can be important even for tiny values of the couplings.
[ { "created": "Wed, 7 Apr 2021 18:26:47 GMT", "version": "v1" }, { "created": "Tue, 18 May 2021 09:37:53 GMT", "version": "v2" }, { "created": "Wed, 9 Jun 2021 11:31:51 GMT", "version": "v3" }, { "created": "Thu, 10 Jun 2021 10:02:13 GMT", "version": "v4" }, { "created": "Tue, 30 May 2023 19:11:54 GMT", "version": "v5" }, { "created": "Sat, 17 Feb 2024 19:57:23 GMT", "version": "v6" }, { "created": "Sun, 31 Mar 2024 11:25:26 GMT", "version": "v7" } ]
2024-04-02
[ [ "Lebedev", "Oleg", "" ] ]
The discovery of the Higgs boson has opened a new avenue for exploring physics beyond the Standard Model. In this review, we discuss cosmological aspects of the simplest Higgs couplings to the hidden sector, known as the Higgs portal. We focus on implications of such couplings for inflation, vacuum stability and dark matter, with the latter including both the traditional weakly interacting massive particles as well as feebly interacting scalars. The cosmological impact of the Higgs portal can be important even for tiny values of the couplings.
1211.2642
Sergey Alekhin
S. Alekhin, J. Bluemlein, S.-O. Moch
Statistical issues in the parton distribution analysis of the Tevatron jet data
13 pages, 8 figures
null
null
DESY-12-191; DO-TH~12/34; LPN12-118; SFB/CPP-12-79
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We analyse a tension between the D0 and CDF inclusive jet data and the perturbative QCD calculations, which are based on the ABKM09 and ABM11 parton distribution functions (PDFs) within the nuisance parameter framework. Particular attention is paid on the uncertainties in the nuisance parameters due to the data fluctuations and the PDF errors. We show that with account of these uncertainties the nuisance parameters do not demonstrate a statistically significant excess. A statistical bias of the estimator based on the nuisance parameters is also discussed.
[ { "created": "Mon, 12 Nov 2012 14:44:19 GMT", "version": "v1" } ]
2012-11-13
[ [ "Alekhin", "S.", "" ], [ "Bluemlein", "J.", "" ], [ "Moch", "S. -O.", "" ] ]
We analyse a tension between the D0 and CDF inclusive jet data and the perturbative QCD calculations, which are based on the ABKM09 and ABM11 parton distribution functions (PDFs) within the nuisance parameter framework. Particular attention is paid on the uncertainties in the nuisance parameters due to the data fluctuations and the PDF errors. We show that with account of these uncertainties the nuisance parameters do not demonstrate a statistically significant excess. A statistical bias of the estimator based on the nuisance parameters is also discussed.
hep-ph/0209051
Bogdan Mihaila
Fred Cooper, John F. Dawson, and Bogdan Mihaila
Quantum dynamics of phase transitions in broken symmetry $\lambda \phi^4$ field theory
28 pages, 21 figures; ver 2 -- additional comments on the nature of the phase transition in 1+1 dimensions
Phys.Rev.D67:056003,2003
10.1103/PhysRevD.67.056003
LA-UR-02-5413
hep-ph
null
We perform a detailed numerical investigation of the dynamics of broken symmetry $\lambda \phi^4$ field theory in 1+1 dimensions using a Schwinger-Dyson equation truncation scheme based on ignoring vertex corrections. In an earlier paper, we called this the bare vertex approximation (BVA). We assume the initial state is described by a Gaussian density matrix peaked around some non-zero value of $<\phi(0)>$, and characterized by a single particle Bose-Einstein distribution function at a given temperature. We compute the evolution of the system using three different approximations: Hartree, BVA and a related 2PI-1/N expansion, as a function of coupling strength and initial temperature. In the Hartree approximation, the static phase diagram shows that there is a first order phase transition for this system. As we change the initial starting temperature of the system, we find that the BVA relaxes to a new final temperature and exhibits a second order phase transition. We find that the average fields thermalize for arbitrary initial conditions in the BVA, unlike the behavior exhibited by the Hartree approximation, and we illustrate how $<\phi(t)>$ and $<\chi(t)>$ depend on the initial temperature and on the coupling constant. We find that the 2PI-1/N expansion gives dramatically different results for $<\phi(t)>$.
[ { "created": "Thu, 5 Sep 2002 14:04:54 GMT", "version": "v1" }, { "created": "Mon, 4 Nov 2002 22:05:05 GMT", "version": "v2" }, { "created": "Wed, 6 Nov 2002 19:55:17 GMT", "version": "v3" } ]
2014-11-17
[ [ "Cooper", "Fred", "" ], [ "Dawson", "John F.", "" ], [ "Mihaila", "Bogdan", "" ] ]
We perform a detailed numerical investigation of the dynamics of broken symmetry $\lambda \phi^4$ field theory in 1+1 dimensions using a Schwinger-Dyson equation truncation scheme based on ignoring vertex corrections. In an earlier paper, we called this the bare vertex approximation (BVA). We assume the initial state is described by a Gaussian density matrix peaked around some non-zero value of $<\phi(0)>$, and characterized by a single particle Bose-Einstein distribution function at a given temperature. We compute the evolution of the system using three different approximations: Hartree, BVA and a related 2PI-1/N expansion, as a function of coupling strength and initial temperature. In the Hartree approximation, the static phase diagram shows that there is a first order phase transition for this system. As we change the initial starting temperature of the system, we find that the BVA relaxes to a new final temperature and exhibits a second order phase transition. We find that the average fields thermalize for arbitrary initial conditions in the BVA, unlike the behavior exhibited by the Hartree approximation, and we illustrate how $<\phi(t)>$ and $<\chi(t)>$ depend on the initial temperature and on the coupling constant. We find that the 2PI-1/N expansion gives dramatically different results for $<\phi(t)>$.
1011.1854
Samuel Wallon
I. V. Anikin, D. Yu. Ivanov, B. Pire, L. Szymanowski, S. Wallon
Exclusive electroproduction of rhoT meson with twist three accuracy
5 pages, to appear in the proceedings of 35th International Conference on High Energy Physics, (ICHEP 2010), Paris, France, July 22-28, 2010
PoS ICHEP2010:121,2010
null
LPT-ORSAY-10-86
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Exclusive electroproduction of vector mesons is a crucial way to probe QCD factorization properties. Such a factorization is up to now only proven, at the twist 2 level, for a longitudinaly polarized meson. It is crucial to extend our understanding to the case of transversely polarized vector mesons. As a first step in this direction, we evaluate the impact factor of the transition gamma* -> rhoT, which is the relevant part of the amplitude within the kt-factorization approach valid at large energies, taking into account the twist 3 contributions, coming both from quark antiquark and from quark antiquark gluon correlators. We show that a gauge invariant expression is obtained with the help of QCD equations of motion.
[ { "created": "Mon, 8 Nov 2010 17:22:44 GMT", "version": "v1" } ]
2011-04-22
[ [ "Anikin", "I. V.", "" ], [ "Ivanov", "D. Yu.", "" ], [ "Pire", "B.", "" ], [ "Szymanowski", "L.", "" ], [ "Wallon", "S.", "" ] ]
Exclusive electroproduction of vector mesons is a crucial way to probe QCD factorization properties. Such a factorization is up to now only proven, at the twist 2 level, for a longitudinaly polarized meson. It is crucial to extend our understanding to the case of transversely polarized vector mesons. As a first step in this direction, we evaluate the impact factor of the transition gamma* -> rhoT, which is the relevant part of the amplitude within the kt-factorization approach valid at large energies, taking into account the twist 3 contributions, coming both from quark antiquark and from quark antiquark gluon correlators. We show that a gauge invariant expression is obtained with the help of QCD equations of motion.
hep-ph/0306153
Ulrich Jentschura
Ulrich D. Jentschura
Quantum Electrodynamic Bound-State Calculations and Large-Order Perturbation Theory
124 pages; based on a habilitation thesis (2003), University of Dresden; references to the work by Mastrolia, Bonciani and Remiddi updated
null
null
null
hep-ph
null
The subjects which are discussed in this Thesis include: the self energy of a bound electron and the spin-dependence of QED corrections in bound systems, convergence acceleration techniques, and resummation methods for divergent series with an emphasis on physical applications.
[ { "created": "Tue, 17 Jun 2003 10:57:25 GMT", "version": "v1" }, { "created": "Tue, 27 Apr 2004 11:06:33 GMT", "version": "v2" } ]
2007-05-23
[ [ "Jentschura", "Ulrich D.", "" ] ]
The subjects which are discussed in this Thesis include: the self energy of a bound electron and the spin-dependence of QED corrections in bound systems, convergence acceleration techniques, and resummation methods for divergent series with an emphasis on physical applications.
0705.1188
Donal O'Connell
Jose Ramon Espinosa, Benjamin Grinstein, Donal O'Connell and Mark B. Wise
Neutrino Masses in the Lee-Wick Standard Model
7 pages, 1 figure
Phys.Rev.D77:085002,2008
10.1103/PhysRevD.77.085002
CALT 68-2647, IFT-UAM/CSIC-07-21, UCSD/PTH 07-05
hep-ph
null
Recently, an extension of the standard model based on ideas of Lee and Wick has been discussed. This theory is free of quadratic divergences and hence has a Higgs mass that is stable against radiative corrections. Here, we address the question of whether or not it is possible to couple very heavy particles, with masses much greater than the weak scale, to the Lee-Wick standard model degrees of freedom and still preserve the stability of the weak scale. We show that in the LW-standard model the familiar see-saw mechanism for generating neutrino masses preserves the solution to the hierarchy puzzle provided by the higher derivative terms. The very heavy right handed neutrinos do not destabilize the Higgs mass. We give an example of new heavy degrees of freedom that would destabilize the hierarchy, and discuss a general mechanism for coupling other heavy degrees of freedom to the Higgs doublet while preserving the hierarchy.
[ { "created": "Wed, 9 May 2007 04:22:32 GMT", "version": "v1" } ]
2008-11-26
[ [ "Espinosa", "Jose Ramon", "" ], [ "Grinstein", "Benjamin", "" ], [ "O'Connell", "Donal", "" ], [ "Wise", "Mark B.", "" ] ]
Recently, an extension of the standard model based on ideas of Lee and Wick has been discussed. This theory is free of quadratic divergences and hence has a Higgs mass that is stable against radiative corrections. Here, we address the question of whether or not it is possible to couple very heavy particles, with masses much greater than the weak scale, to the Lee-Wick standard model degrees of freedom and still preserve the stability of the weak scale. We show that in the LW-standard model the familiar see-saw mechanism for generating neutrino masses preserves the solution to the hierarchy puzzle provided by the higher derivative terms. The very heavy right handed neutrinos do not destabilize the Higgs mass. We give an example of new heavy degrees of freedom that would destabilize the hierarchy, and discuss a general mechanism for coupling other heavy degrees of freedom to the Higgs doublet while preserving the hierarchy.
2404.00064
Igor Ivanov
Igor P. Ivanov, Duanyang Zhao
Confronting CP symmetry of order 4 with experimental data
14 pages, 3 figures, Proceedings of the "Workshop on the Standard Model and Beyond" within the Corfu Summer Institute 2023, Corfu, Greece, August 27 - September 7, 2023
PoS(CORFU2023)086
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
CP4 3HDM is a three-Higgs-doublet model based on a $CP$ symmetry of order 4 (CP4). It is the minimal model incorporating CP4 without leading to accidental symmetries or running into immediate conflict with experiment. Imposing CP4 on the lagrangian induces remarkably tight connections between the scalar and Yukawa sectors, including the unavoidable tree-level flavor-changing neutral couplings (FCNC). Here, we explore whether it is at all possible in the CP4 3HDM to suppressed FCNC to a level compatible with the neutral meson oscillation constraints. We express the FCNC matrices in terms of physical quark observables and quark rotation parameters, and scan the Yukawa parameter space using the quark masses and mixing parameters as input. With this procedure, we find that only two out of the eight possible CP4 Yukawa sectors are compatible with the $K$, $B$, $B_s$ and, in particular, $D$-meson oscillation constraints. The results clearly indicate a way how to construct phenomenologically viable benchmark CP4 3HDMs.
[ { "created": "Thu, 28 Mar 2024 06:57:44 GMT", "version": "v1" } ]
2024-04-02
[ [ "Ivanov", "Igor P.", "" ], [ "Zhao", "Duanyang", "" ] ]
CP4 3HDM is a three-Higgs-doublet model based on a $CP$ symmetry of order 4 (CP4). It is the minimal model incorporating CP4 without leading to accidental symmetries or running into immediate conflict with experiment. Imposing CP4 on the lagrangian induces remarkably tight connections between the scalar and Yukawa sectors, including the unavoidable tree-level flavor-changing neutral couplings (FCNC). Here, we explore whether it is at all possible in the CP4 3HDM to suppressed FCNC to a level compatible with the neutral meson oscillation constraints. We express the FCNC matrices in terms of physical quark observables and quark rotation parameters, and scan the Yukawa parameter space using the quark masses and mixing parameters as input. With this procedure, we find that only two out of the eight possible CP4 Yukawa sectors are compatible with the $K$, $B$, $B_s$ and, in particular, $D$-meson oscillation constraints. The results clearly indicate a way how to construct phenomenologically viable benchmark CP4 3HDMs.
1010.4309
Ian Lewis
Tao Han, Ian Lewis, and Zhen Liu
Colored Resonant Signals at the LHC: Largest Rate and Simplest Topology
29 pages, 9 figures. References updated and additional K-factors included
JHEP 1012:085, 2010
10.1007/JHEP12(2010)085
MADPH--10-1563
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the colored resonance production at the LHC in a most general approach. We classify the possible colored resonances based on group theory decomposition, and construct their effective interactions with light partons. The production cross section from annihilation of valence quarks or gluons may be on the order of 400 - 1000 pb at LHC energies for a mass of 1 TeV with nominal couplings, leading to the largest production rates for new physics at the TeV scale, and simplest event topology with dijet final states. We apply the new dijet data from the LHC experiments to put bounds on various possible colored resonant states. The current bounds range from 0.9 to 2.7 TeV. The formulation is readily applicable for future searches including other decay modes.
[ { "created": "Wed, 20 Oct 2010 20:08:14 GMT", "version": "v1" }, { "created": "Thu, 9 Dec 2010 14:59:38 GMT", "version": "v2" } ]
2010-12-30
[ [ "Han", "Tao", "" ], [ "Lewis", "Ian", "" ], [ "Liu", "Zhen", "" ] ]
We study the colored resonance production at the LHC in a most general approach. We classify the possible colored resonances based on group theory decomposition, and construct their effective interactions with light partons. The production cross section from annihilation of valence quarks or gluons may be on the order of 400 - 1000 pb at LHC energies for a mass of 1 TeV with nominal couplings, leading to the largest production rates for new physics at the TeV scale, and simplest event topology with dijet final states. We apply the new dijet data from the LHC experiments to put bounds on various possible colored resonant states. The current bounds range from 0.9 to 2.7 TeV. The formulation is readily applicable for future searches including other decay modes.
2306.04728
Henrique Boschi-Filho
Rafael A. Costa-Silva and Henrique Boschi-Filho
Anomalous and Linear Holographic Hard Wall Models for Glueballs and the Pomeron
35 pages, 6 tables, 5 figures. Text and numerical analysis improved. In this revised version we included errors for all calculated glueball masses and the corresponding error bars in figures
Physical Review D 109, 086019 (2024)
10.1103/PhysRevD.109.086019
null
hep-ph hep-th
http://creativecommons.org/licenses/by/4.0/
In this work we propose improved holographic hard wall (HW) models by the inclusion of anomalous dimensions in the dual operators that describe glueballs inspired by the AdS/CFT correspondence. The anomalous dimensions come from well known semi-classical gauge/string duality analysis showing a dependence with the logarithm of spin $S$ of the boundary states. We show that these logarithm anomalous dimensions of the high spin operators combined with the usual HW model allow us to match the pomeron trajectory and give glueball masses which are better than that of the original HW and soft wall (SW) models in comparison with lattice data. We also build up other anomalous HW (AHW) models considering that the logarithm anomalous dimensions can be approximated by a truncated series of odd powers of the difference $\sqrt{S}-1/\sqrt{S}$. These models also fit the pomeron trajectory and produce good glueball masses. Then, we consider an anomalous dimension which is proportional to $\sqrt{S}$, providing reasonable results. Finally, we propose an asymptotic linear AHW model which effective dimensions for high spins operators are of the form $\Delta=a\sqrt{S}+b$, where $a$ and $b$ are constants to be fixed by comparison with the soft pomeron trajectory. In this last model, the Regge trajectory is asymptotically linear even for very high spins ($J\sim 100$) matching the soft pomeron trajectory accurately and generates glueball masses with deviations with respect to the lattice data better than the original HW and SW models.
[ { "created": "Wed, 7 Jun 2023 18:44:56 GMT", "version": "v1" }, { "created": "Wed, 18 Oct 2023 19:19:50 GMT", "version": "v2" }, { "created": "Mon, 18 Mar 2024 23:05:54 GMT", "version": "v3" } ]
2024-04-25
[ [ "Costa-Silva", "Rafael A.", "" ], [ "Boschi-Filho", "Henrique", "" ] ]
In this work we propose improved holographic hard wall (HW) models by the inclusion of anomalous dimensions in the dual operators that describe glueballs inspired by the AdS/CFT correspondence. The anomalous dimensions come from well known semi-classical gauge/string duality analysis showing a dependence with the logarithm of spin $S$ of the boundary states. We show that these logarithm anomalous dimensions of the high spin operators combined with the usual HW model allow us to match the pomeron trajectory and give glueball masses which are better than that of the original HW and soft wall (SW) models in comparison with lattice data. We also build up other anomalous HW (AHW) models considering that the logarithm anomalous dimensions can be approximated by a truncated series of odd powers of the difference $\sqrt{S}-1/\sqrt{S}$. These models also fit the pomeron trajectory and produce good glueball masses. Then, we consider an anomalous dimension which is proportional to $\sqrt{S}$, providing reasonable results. Finally, we propose an asymptotic linear AHW model which effective dimensions for high spins operators are of the form $\Delta=a\sqrt{S}+b$, where $a$ and $b$ are constants to be fixed by comparison with the soft pomeron trajectory. In this last model, the Regge trajectory is asymptotically linear even for very high spins ($J\sim 100$) matching the soft pomeron trajectory accurately and generates glueball masses with deviations with respect to the lattice data better than the original HW and SW models.
1705.04169
Umberto D'Alesio
Umberto D'Alesio, Francesco Murgia, Cristian Pisano, and Pieter Taels
Probing the gluon Sivers function in $p^\uparrow p\to J/\psi\,X$ and $p^\uparrow p \to D\,X$
19 pages, 8 figures, 1 table; v2: minor changes, matches the published version
Phys. Rev. D 96, 036011 (2017)
10.1103/PhysRevD.96.036011
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a study of transverse single-spin asymmetries (SSAs) in $p^\uparrow p\to J/\psi\,X$ and $p^\uparrow p\to D X$ within the framework of the generalized parton model (GPM), which includes both spin and transverse momentum effects, and show how they can provide useful information on the still almost unknown gluon Sivers function. Moreover, by adopting a modified version of this model, named color gauge invariant (CGI) GPM, we analyze the impact of the initial- and final-state interactions on our predictions. As a consequence, we find that these two processes are sensitive to different gluon Sivers functions, which can be expressed as linear combinations of two distinct, universal gluon distributions. We therefore define proper observables which could allow for a separate extraction of these two independent Sivers functions. At the same time, we show how it would be possible to discriminate between the GPM and the CGI-GPM approaches by comparing the corresponding estimates of SSAs with present and future experimental results at RHIC.
[ { "created": "Thu, 11 May 2017 13:31:42 GMT", "version": "v1" }, { "created": "Mon, 4 Sep 2017 19:34:39 GMT", "version": "v2" } ]
2017-09-06
[ [ "D'Alesio", "Umberto", "" ], [ "Murgia", "Francesco", "" ], [ "Pisano", "Cristian", "" ], [ "Taels", "Pieter", "" ] ]
We present a study of transverse single-spin asymmetries (SSAs) in $p^\uparrow p\to J/\psi\,X$ and $p^\uparrow p\to D X$ within the framework of the generalized parton model (GPM), which includes both spin and transverse momentum effects, and show how they can provide useful information on the still almost unknown gluon Sivers function. Moreover, by adopting a modified version of this model, named color gauge invariant (CGI) GPM, we analyze the impact of the initial- and final-state interactions on our predictions. As a consequence, we find that these two processes are sensitive to different gluon Sivers functions, which can be expressed as linear combinations of two distinct, universal gluon distributions. We therefore define proper observables which could allow for a separate extraction of these two independent Sivers functions. At the same time, we show how it would be possible to discriminate between the GPM and the CGI-GPM approaches by comparing the corresponding estimates of SSAs with present and future experimental results at RHIC.
hep-ph/0601205
Umberto D'Alesio
M. Anselmino (1), M. Boglione (1), U. D'Alesio (2), E. Leader (3), S. Melis (2), F. Murgia (2) ((1) University and INFN, Torino, Italy, (2) University and INFN, Cagliari, Italy, (3) Imperial College, London, UK)
General helicity formalism for Single and Double Spin Asymmetries in p p --> pion + X
LaTeX, 5 pages, 1 eps figure, uses epsfig, wrapfig. Talk delivered by S. Melis at the ``XI Workshop on High Energy Spin Physics'', SPIN 05, September 27 - October 1, 2005, Dubna, Russia
null
null
null
hep-ph
null
We consider within a generalized QCD factorization approach, the high energy inclusive polarized process p p --> pion + X, including all intrinsic partonic motions. Several new spin and k_T-dependent soft functions appear and contribute to cross sections and spin asymmetries. We present here formal expressions for transverse single spin asymmetries and double longitudinal ones. The transverse single spin asymmetry, A_N, is considered in detail, and all contributions are evaluated numerically. It is shown that the azimuthal phase integrations strongly suppress most contributions, leaving at work mainly the Sivers effect.
[ { "created": "Wed, 25 Jan 2006 15:13:15 GMT", "version": "v1" } ]
2007-05-23
[ [ "Anselmino", "M.", "" ], [ "Boglione", "M.", "" ], [ "D'Alesio", "U.", "" ], [ "Leader", "E.", "" ], [ "Melis", "S.", "" ], [ "Murgia", "F.", "" ] ]
We consider within a generalized QCD factorization approach, the high energy inclusive polarized process p p --> pion + X, including all intrinsic partonic motions. Several new spin and k_T-dependent soft functions appear and contribute to cross sections and spin asymmetries. We present here formal expressions for transverse single spin asymmetries and double longitudinal ones. The transverse single spin asymmetry, A_N, is considered in detail, and all contributions are evaluated numerically. It is shown that the azimuthal phase integrations strongly suppress most contributions, leaving at work mainly the Sivers effect.
hep-ph/0007042
Dorota Kotlorz
Dorota Kotlorz
Nucleon Spin Structure Functions
The shorter version of this paper has been accepted to publication in Acta Physica Polonica B
null
null
null
hep-ph
null
The review of the nucleon spin structure functions problems is presented. The perturbative QCD predictions for the small x behaviour of the nucleon spin structure functions are discussed. The role of the resummation of the ln^2 1/x terms is emphasized. Predictions for the nonsinglet structure function g_1 in case of a flat as well as a dynamical input are given. The so called "spin crisis" on the context of both theoretical and experimental future hopes are also briefly discussed.
[ { "created": "Wed, 5 Jul 2000 12:58:16 GMT", "version": "v1" } ]
2007-05-23
[ [ "Kotlorz", "Dorota", "" ] ]
The review of the nucleon spin structure functions problems is presented. The perturbative QCD predictions for the small x behaviour of the nucleon spin structure functions are discussed. The role of the resummation of the ln^2 1/x terms is emphasized. Predictions for the nonsinglet structure function g_1 in case of a flat as well as a dynamical input are given. The so called "spin crisis" on the context of both theoretical and experimental future hopes are also briefly discussed.
0708.1306
Alan R. White
Alan R. White
The LHC Pomeron and Unification of the Standard Model - a Bound-State S-Matrix Within a Fixed-Point Field Theory ?
Presented at the Small-x and Diffraction Workshop, Fermilab,March 2007
null
null
null
hep-ph
null
The Critical Pomeron solution of high-energy unitarity leads to a unique underlying massless field theory that might be the origin of the Standard Model. A color sextet quark sector - producing both electroweak symmetry breaking and dark matter - is added to QCD to saturate asymptotic freedom. The sextet sector is then embedded uniquely in ``QUD'' - an anomaly free, just asymptotically free, massless SU(5) theory with elementary lepton and triplet quark sectors very close to the Standard Model. A multi-regge bound-state S-Matrix is constructed using infra-red divergent scaling reggeon interactions that couple via massless fermion chiral anomalies. Within the QCD sub-sector there is an ``anomalous wee gluon'' critical phenomenon that produces a spectrum with confinement and chiral symmetry breaking. The exponentiation of left-handed gauge boson divergences implies that the full set of composite interactions and the low-mass spectrum of QUD could be just those of the Standard Model. All particles, including neutrinos, appear as massive, Goldstone boson related, bound-states and there is no Higgs field. The different coupling strengths, multiple mass scales, and multigenerational structure should also appear. The Critical Pomeron may be the S-Matrix manifestation of the underlying fixed-point field theory. If QUD underlies the Standard Model as described, the sextet sector should produce new, unmistakeable, large cross-sections at the LHC, for which the pomeron could be the main diagnostic!
[ { "created": "Thu, 9 Aug 2007 14:49:39 GMT", "version": "v1" } ]
2007-08-10
[ [ "White", "Alan R.", "" ] ]
The Critical Pomeron solution of high-energy unitarity leads to a unique underlying massless field theory that might be the origin of the Standard Model. A color sextet quark sector - producing both electroweak symmetry breaking and dark matter - is added to QCD to saturate asymptotic freedom. The sextet sector is then embedded uniquely in ``QUD'' - an anomaly free, just asymptotically free, massless SU(5) theory with elementary lepton and triplet quark sectors very close to the Standard Model. A multi-regge bound-state S-Matrix is constructed using infra-red divergent scaling reggeon interactions that couple via massless fermion chiral anomalies. Within the QCD sub-sector there is an ``anomalous wee gluon'' critical phenomenon that produces a spectrum with confinement and chiral symmetry breaking. The exponentiation of left-handed gauge boson divergences implies that the full set of composite interactions and the low-mass spectrum of QUD could be just those of the Standard Model. All particles, including neutrinos, appear as massive, Goldstone boson related, bound-states and there is no Higgs field. The different coupling strengths, multiple mass scales, and multigenerational structure should also appear. The Critical Pomeron may be the S-Matrix manifestation of the underlying fixed-point field theory. If QUD underlies the Standard Model as described, the sextet sector should produce new, unmistakeable, large cross-sections at the LHC, for which the pomeron could be the main diagnostic!
1210.6369
Mathieu Buchkremer Mr.
Mathieu Buchkremer, Alexander Schmidt
Long-lived heavy quarks : a review
17 pages, 9 figures, 8 tables. Version accepted for publication in AHEP on Very Heavy Quarks at the LHC. Version 2: References added and last section updated
Adv.High Energy Phys. 2013 (2013) 690254
null
CP3-12-31
hep-ph hep-ex
http://creativecommons.org/licenses/by/3.0/
We review the theoretical and experimental situation for long-lived heavy quarks, or bound states thereof, arising in simple extensions of the Standard Model. If these particles propagate large distances before their decay, they give rise to specific signatures requiring dedicated analysis methods. In particular, vector-like quarks with negligible couplings to the three known families could have eluded the past experimental searches. While most analyses assume prompt decays at the production vertex, novel heavy quarks might lead to signatures involving displaced vertices, new hadronic bound states, or decays happening outside of the detector acceptance. We perform reinterpretations of existing searches for short- and long-lived particles, and give suggestions on how to extend their reach to long-lived heavy quarks.
[ { "created": "Tue, 23 Oct 2012 20:25:48 GMT", "version": "v1" }, { "created": "Fri, 5 Apr 2013 15:35:41 GMT", "version": "v2" } ]
2013-04-08
[ [ "Buchkremer", "Mathieu", "" ], [ "Schmidt", "Alexander", "" ] ]
We review the theoretical and experimental situation for long-lived heavy quarks, or bound states thereof, arising in simple extensions of the Standard Model. If these particles propagate large distances before their decay, they give rise to specific signatures requiring dedicated analysis methods. In particular, vector-like quarks with negligible couplings to the three known families could have eluded the past experimental searches. While most analyses assume prompt decays at the production vertex, novel heavy quarks might lead to signatures involving displaced vertices, new hadronic bound states, or decays happening outside of the detector acceptance. We perform reinterpretations of existing searches for short- and long-lived particles, and give suggestions on how to extend their reach to long-lived heavy quarks.
hep-ph/0004190
Juan Antonio Aguilar Saavedra
J. A. Aguilar-Saavedra, G. C. Branco
Probing top flavour-changing neutral scalar couplings at the CERN LHC
Uses elsart.cls. 16 pages, 9 PS figures. Some comments and references added. Final version to appear in PLB
Phys.Lett.B495:347-356,2000
10.1016/S0370-2693(00)01259-4
UG-FT-113/00, FIST/4-2000/CFIF
hep-ph
null
Top decays into a light Higgs boson and an up or charm quark can reach detectable levels in Standard Model extensions with two Higgs doublets or with new exotic quarks, and in the Minimal Supersymmetric Standard Model. Using both a standard and a neural network analysis we show that the CERN Large Hadron Collider will give 3 sigma evidence of decays with Br(t -> Hc) >= 6.5 10^-5 or set a limit Br(t -> Hc) <= 4.5 10^-5 with a 95% confidence level if these decays are not observed. We also consider limits obtained from single top production associated with a neutral Higgs boson.
[ { "created": "Thu, 20 Apr 2000 08:22:36 GMT", "version": "v1" }, { "created": "Tue, 2 May 2000 16:35:21 GMT", "version": "v2" }, { "created": "Thu, 2 Nov 2000 19:03:29 GMT", "version": "v3" } ]
2008-11-26
[ [ "Aguilar-Saavedra", "J. A.", "" ], [ "Branco", "G. C.", "" ] ]
Top decays into a light Higgs boson and an up or charm quark can reach detectable levels in Standard Model extensions with two Higgs doublets or with new exotic quarks, and in the Minimal Supersymmetric Standard Model. Using both a standard and a neural network analysis we show that the CERN Large Hadron Collider will give 3 sigma evidence of decays with Br(t -> Hc) >= 6.5 10^-5 or set a limit Br(t -> Hc) <= 4.5 10^-5 with a 95% confidence level if these decays are not observed. We also consider limits obtained from single top production associated with a neutral Higgs boson.