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hep-ph/9702209
Mustafa Savci
T. M. Aliev, A. Ozpineci, M. Savci (Middle East Technical University-Ankara-Turkey), H. Koru (Gazi University-Ankara-Turkey)
Light cone QCD sum rule analysis of B -> K l(+) l(-) decay
18 pages, 3 figures, LaTeX formatted
Phys.Lett. B400 (1997) 194-205
10.1016/S0370-2693(97)00327-4
METU-PHYS-HEP-97-3
hep-ph
null
We calculate the transition formfactors for the B -> K l(+) l(-) decay in the framework of the light cone QCD sum rules. The invariant dilepton mass distribution and the final lepton longitudinal polarization asymmetry are investigated. The comparison analysis of our results with traditional sum rules method predictions on the formfactors is performed.
[ { "created": "Fri, 31 Jan 1997 15:58:32 GMT", "version": "v1" }, { "created": "Sat, 22 Mar 1997 16:38:07 GMT", "version": "v2" } ]
2009-10-30
[ [ "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" ], [ "Koru", "H.", "", "Gazi University-Ankara-Turkey" ] ]
We calculate the transition formfactors for the B -> K l(+) l(-) decay in the framework of the light cone QCD sum rules. The invariant dilepton mass distribution and the final lepton longitudinal polarization asymmetry are investigated. The comparison analysis of our results with traditional sum rules method predictions on the formfactors is performed.
1512.05898
Quentin Wallemacq
Quentin Wallemacq
Composite dark matter and direct-search experiments
PhD thesis, defended on September 9, 2015 at the University of Li\`ege, Belgium
null
10.1142/S0218271815450066
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We reinterpret the results of the direct searches for dark matter in terms of composite dark matter, i.e. dark matter particles that form neutral bound states, generically called dark atoms, either with ordinary particles, or with other dark matter particles. Three different scenarios are investigated: the O-helium scenario, milli- interacting dark matter and dark anti-atoms. In each of them, dark matter interacts sufficiently strongly with terrestrial matter to be stopped in it before reaching underground detectors. As they drift towards the center of the earth by gravity, these thermal dark atoms are radiatively captured by the atoms of the active medium of underground detectors, which causes the emission of photons that produce the signals through their interactions with the electrons of the medium. This provides a way of reinterpreting the results in terms of electron recoils instead of nuclear recoils. The detailed study of the interactions of O-helium with ordinary matter shows that it is not an acceptable candidate for dark matter because of the absence of a repulsion mechanism preventing it from falling into the deep nuclear wells of nuclei. The two other models involve milli-charges and are able to reconcile the most contradictory experiments. We determine, for each model, the regions in the parameter space that reproduce the experiments with positive results in full consistency with the constraints of the experiments with negative results. We also pay attention to the experimental and observational constraints on milli-charges and discuss some typical signatures of the models that could be used to test them.
[ { "created": "Fri, 18 Dec 2015 10:51:52 GMT", "version": "v1" } ]
2016-01-20
[ [ "Wallemacq", "Quentin", "" ] ]
We reinterpret the results of the direct searches for dark matter in terms of composite dark matter, i.e. dark matter particles that form neutral bound states, generically called dark atoms, either with ordinary particles, or with other dark matter particles. Three different scenarios are investigated: the O-helium scenario, milli- interacting dark matter and dark anti-atoms. In each of them, dark matter interacts sufficiently strongly with terrestrial matter to be stopped in it before reaching underground detectors. As they drift towards the center of the earth by gravity, these thermal dark atoms are radiatively captured by the atoms of the active medium of underground detectors, which causes the emission of photons that produce the signals through their interactions with the electrons of the medium. This provides a way of reinterpreting the results in terms of electron recoils instead of nuclear recoils. The detailed study of the interactions of O-helium with ordinary matter shows that it is not an acceptable candidate for dark matter because of the absence of a repulsion mechanism preventing it from falling into the deep nuclear wells of nuclei. The two other models involve milli-charges and are able to reconcile the most contradictory experiments. We determine, for each model, the regions in the parameter space that reproduce the experiments with positive results in full consistency with the constraints of the experiments with negative results. We also pay attention to the experimental and observational constraints on milli-charges and discuss some typical signatures of the models that could be used to test them.
1910.06275
Christopher Wever
Costas G. Papadopoulos and Christopher Wever
Internal Reduction method for computing Feynman Integrals
18 pages, 4 figures, 1 table
https://doi.org/10.1007/JHEP02(2020)112
10.1007/JHEP02(2020)112
TUM-HEP-1232/19
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A new approach to compute Feynman Integrals is presented. It relies on an integral representation of a given Feynman Integral in terms of simpler ones. Using this approach, we present, for the first time, results for a certain family of non-planar five-point two-loop Master Integrals with one external off-shell particle, relevant for instance for $H+2$ jets production at the LHC, in both Euclidean and physical kinematical regions.
[ { "created": "Mon, 14 Oct 2019 17:00:50 GMT", "version": "v1" } ]
2020-03-18
[ [ "Papadopoulos", "Costas G.", "" ], [ "Wever", "Christopher", "" ] ]
A new approach to compute Feynman Integrals is presented. It relies on an integral representation of a given Feynman Integral in terms of simpler ones. Using this approach, we present, for the first time, results for a certain family of non-planar five-point two-loop Master Integrals with one external off-shell particle, relevant for instance for $H+2$ jets production at the LHC, in both Euclidean and physical kinematical regions.
hep-ph/0602092
Mei Huang
Mei Huang
Spontaneous Nambu-Goldstone Currents Generation Driven by Mismatch
22 pages, no figures; contribution to the proceedings of the INT workshop "Pairing in fermionic systems", Seattle, September 19-23, 2005
null
10.1142/9789812773043_0004
TKYNT-06-3
hep-ph
null
We review recent progress of understanding and resolving instabilities driven by mismatch between the Fermi surfaces of the pairing quarks in 2-flavor color superconductor. With the increase of mismatch, the 2SC phase exhibits chromomagnetic instability as well as color neutral baryon current instability. We describe the 2SC phase in the nonlinear realization framework, and show that each instability indicates the spontaneous generation of the corresponding pseudo Nambu-Golstone current. The Nambu-Goldstone currents generation state covers the gluon phase as well as the one-plane wave LOFF state. We further point out that, when charge neutrality condition is required, there exists a narrow unstable LOFF (Us-LOFF) window, where not only off-diagonal gluons but the diagonal 8-th gluon cannot avoid the magnetic instability. In this Us-LOFF window, the diagonal magnetic instability cannot be cured by off-diagonal gluon condensate in the color superconducting phase.
[ { "created": "Fri, 10 Feb 2006 14:40:31 GMT", "version": "v1" } ]
2016-11-09
[ [ "Huang", "Mei", "" ] ]
We review recent progress of understanding and resolving instabilities driven by mismatch between the Fermi surfaces of the pairing quarks in 2-flavor color superconductor. With the increase of mismatch, the 2SC phase exhibits chromomagnetic instability as well as color neutral baryon current instability. We describe the 2SC phase in the nonlinear realization framework, and show that each instability indicates the spontaneous generation of the corresponding pseudo Nambu-Golstone current. The Nambu-Goldstone currents generation state covers the gluon phase as well as the one-plane wave LOFF state. We further point out that, when charge neutrality condition is required, there exists a narrow unstable LOFF (Us-LOFF) window, where not only off-diagonal gluons but the diagonal 8-th gluon cannot avoid the magnetic instability. In this Us-LOFF window, the diagonal magnetic instability cannot be cured by off-diagonal gluon condensate in the color superconducting phase.
1804.08287
Ho-Meoyng Choi
Hui-Young Ryu (Pusan National Univ.), Ho-Meoyng Choi (Kyungpook National Univ.), and Chueng-Ryong Ji (North Carolina State Univ.)
Systematic twist expansion of $(\eta_c,\eta_b)\to\gamma^*\gamma$ transition form factors in light-front quark model
9 pages, 6 figures, Version to appear in Phys.Rev. D. arXiv admin note: text overlap with arXiv:1708.00736
Physical Review D 98, 034018 (2018)
10.1103/PhysRevD.98.034018
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The light-front quark model analysis of the meson-photon transition form factor $F_{P\gamma} (Q^2)$ amenable both for the spacelike region ($Q^2 >0$) and the timelike region ($Q^2 <0$) provides a systematic twist expansion of $Q^2 F_{P\gamma} (Q^2)$ for the high $|Q^2|$ region. Investigating $F_{P\gamma} (Q^2) (P = \eta_c,\eta_b)$ for the entire kinematic regions of $Q^2$, we examine the twist-2 and twist-3 distribution amplitudes of $(\eta_c,\eta_b)$ mesons in the light-front quark model and quantify their contributions to $Q^2 F_{(\eta_c,\eta_b)\gamma}(Q^2)$. Our numerical results for the normalized transition form factor $F_{(\eta_c,\eta_b)\gamma}(Q^2)/F_{(\eta_c,\eta_b)\gamma}(0)$ and the decay width $\Gamma_{(\eta_c,\eta_b)\to\gamma\gamma}$ are compared with the available data checking the sensitivity of our model to the variation of the constituent quark masses.
[ { "created": "Mon, 23 Apr 2018 08:45:36 GMT", "version": "v1" }, { "created": "Thu, 12 Jul 2018 02:08:55 GMT", "version": "v2" }, { "created": "Wed, 8 Aug 2018 02:37:18 GMT", "version": "v3" } ]
2018-09-26
[ [ "Ryu", "Hui-Young", "", "Pusan National Univ." ], [ "Choi", "Ho-Meoyng", "", "Kyungpook\n National Univ." ], [ "Ji", "Chueng-Ryong", "", "North Carolina State Univ." ] ]
The light-front quark model analysis of the meson-photon transition form factor $F_{P\gamma} (Q^2)$ amenable both for the spacelike region ($Q^2 >0$) and the timelike region ($Q^2 <0$) provides a systematic twist expansion of $Q^2 F_{P\gamma} (Q^2)$ for the high $|Q^2|$ region. Investigating $F_{P\gamma} (Q^2) (P = \eta_c,\eta_b)$ for the entire kinematic regions of $Q^2$, we examine the twist-2 and twist-3 distribution amplitudes of $(\eta_c,\eta_b)$ mesons in the light-front quark model and quantify their contributions to $Q^2 F_{(\eta_c,\eta_b)\gamma}(Q^2)$. Our numerical results for the normalized transition form factor $F_{(\eta_c,\eta_b)\gamma}(Q^2)/F_{(\eta_c,\eta_b)\gamma}(0)$ and the decay width $\Gamma_{(\eta_c,\eta_b)\to\gamma\gamma}$ are compared with the available data checking the sensitivity of our model to the variation of the constituent quark masses.
1312.4924
Massimo Blasone Dr
M.Blasone, P.Jizba, G.Lambiase and N.E.Mavromatos
A framework for dynamical generation of flavor mixing
13 pages. Presented at "Symmetries in Science XVI, Bregenz 2013"
null
10.1088/1742-6596/538/1/012003
LCTS/2013-32; KCL-PH-TH/2013-44
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a dynamical mechanism \`a la Nambu--Jona-Lasinio for the generation of masses and mixing for two interacting fermion fields. The analysis is carried out in the framework introduced long ago by Umezawa et al., in which mass generation is achieved via inequivalent representations, and that we generalize to the case of two generations. The method allows a clear identification of the vacuum structure for each physical phase, confirming previous results about the distinct physical nature of the vacuum for fields with definite mass and fields with definite flavor. Implications for the leptonic sector of the Standard Model are briefly discussed.
[ { "created": "Tue, 17 Dec 2013 20:12:04 GMT", "version": "v1" }, { "created": "Sat, 10 May 2014 14:35:13 GMT", "version": "v2" } ]
2015-06-18
[ [ "Blasone", "M.", "" ], [ "Jizba", "P.", "" ], [ "Lambiase", "G.", "" ], [ "Mavromatos", "N. E.", "" ] ]
We present a dynamical mechanism \`a la Nambu--Jona-Lasinio for the generation of masses and mixing for two interacting fermion fields. The analysis is carried out in the framework introduced long ago by Umezawa et al., in which mass generation is achieved via inequivalent representations, and that we generalize to the case of two generations. The method allows a clear identification of the vacuum structure for each physical phase, confirming previous results about the distinct physical nature of the vacuum for fields with definite mass and fields with definite flavor. Implications for the leptonic sector of the Standard Model are briefly discussed.
0811.3842
Juan Antonio Aguilar-Saavedra
J. A. Aguilar-Saavedra
A minimal set of top anomalous couplings
LaTeX 29 pages, 3 PS figures. Minor comments added, final version to appear in NPB
Nucl.Phys.B812:181-204,2009
10.1016/j.nuclphysb.2008.12.012
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We simplify the general form of the fermion-fermion-gauge boson interactions generated by dimension-six gauge-invariant effective operators by using the equations of motion to remove redundant operators. It is found that the most general vertex for off-shell fermions fi, fj and an off-shell boson V=W,Z,gamma,g only involves gamma^mu and sigma^{mu nu} q_nu terms, with q=p_i-p_j. Examples are given for the Wtb, Ztt, gamma tt and gtt interactions, whose general expression is greatly simplified with respect to previous results in the literature. The same arguments apply to top flavour-changing neutral interactions with the Z boson, the photon or the gluon, which can also be parameterised in full generality with only gamma^mu and sigma^{mu nu} q_nu couplings. Explicit expressions are given for these vertices in terms of dimension-six gauge-invariant operators. We also discuss how effective operator coefficients might be determined from eventual measurements of anomalous couplings.
[ { "created": "Mon, 24 Nov 2008 18:22:06 GMT", "version": "v1" }, { "created": "Thu, 11 Dec 2008 22:30:24 GMT", "version": "v2" } ]
2014-11-18
[ [ "Aguilar-Saavedra", "J. A.", "" ] ]
We simplify the general form of the fermion-fermion-gauge boson interactions generated by dimension-six gauge-invariant effective operators by using the equations of motion to remove redundant operators. It is found that the most general vertex for off-shell fermions fi, fj and an off-shell boson V=W,Z,gamma,g only involves gamma^mu and sigma^{mu nu} q_nu terms, with q=p_i-p_j. Examples are given for the Wtb, Ztt, gamma tt and gtt interactions, whose general expression is greatly simplified with respect to previous results in the literature. The same arguments apply to top flavour-changing neutral interactions with the Z boson, the photon or the gluon, which can also be parameterised in full generality with only gamma^mu and sigma^{mu nu} q_nu couplings. Explicit expressions are given for these vertices in terms of dimension-six gauge-invariant operators. We also discuss how effective operator coefficients might be determined from eventual measurements of anomalous couplings.
2111.06047
Ayodele Ore
Matthew J. Dolan and Ayodele Ore
Meta-learning and data augmentation for mass-generalised jet taggers
12 pages, 5 figures, v2: Table 1 revised
Phys. Rev. D 105, 094030 (2022)
10.1103/PhysRevD.105.094030
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Deep neural networks trained for jet tagging are typically specific to a narrow range of transverse momenta or jet masses. Given the large phase space that the LHC is able to probe, the potential benefit of classifiers that are effective over a wide range of masses or transverse momenta is significant. In this work we benchmark the performance of a number of methods for achieving accurate classification at masses distant from those used in training, with a focus on algorithms that leverage meta-learning. We study the discrimination of jets from boosted $Z'$ bosons against a QCD background. We find that a simple data augmentation strategy that standardises the angular scale of jets with different masses is sufficient to produce strong generalisation. The meta-learning algorithms provide only a small improvement in generalisation when combined with this augmentation. We also comment on the relationship between mass generalisation and mass decorrelation, demonstrating that those models which generalise better than the baseline also sculpt the background to a smaller degree.
[ { "created": "Thu, 11 Nov 2021 04:30:00 GMT", "version": "v1" }, { "created": "Thu, 18 Nov 2021 05:47:34 GMT", "version": "v2" } ]
2022-06-03
[ [ "Dolan", "Matthew J.", "" ], [ "Ore", "Ayodele", "" ] ]
Deep neural networks trained for jet tagging are typically specific to a narrow range of transverse momenta or jet masses. Given the large phase space that the LHC is able to probe, the potential benefit of classifiers that are effective over a wide range of masses or transverse momenta is significant. In this work we benchmark the performance of a number of methods for achieving accurate classification at masses distant from those used in training, with a focus on algorithms that leverage meta-learning. We study the discrimination of jets from boosted $Z'$ bosons against a QCD background. We find that a simple data augmentation strategy that standardises the angular scale of jets with different masses is sufficient to produce strong generalisation. The meta-learning algorithms provide only a small improvement in generalisation when combined with this augmentation. We also comment on the relationship between mass generalisation and mass decorrelation, demonstrating that those models which generalise better than the baseline also sculpt the background to a smaller degree.
1007.1297
Eran Palti
Emilian Dudas, Eran Palti
On hypercharge flux and exotics in F-theory GUTs
38 pages; v2: emphasised possibility of avoiding exotics in models without a global E8 structure, added ref, journal version
JHEP 1009:013,2010
10.1007/JHEP09(2010)013
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study SU(5) Grand Unified Theories within a local framework in F-theory with multiple extra U(1) symmetries arising from a small monodromy group. The use of hypercharge flux for doublet-triplet splitting implies massless exotics in the spectrum that are protected from obtaining a mass by the U(1) symmetries. We find that lifting the exotics by giving vacuum expectation values to some GUT singlets spontaneously breaks all the U(1) symmetries which implies that proton decay operators are induced. If we impose an additional R-parity symmetry by hand we find all the exotics can be lifted while proton decay operators are still forbidden. These models can retain the gauge coupling unification accuracy of the MSSM at 1-loop. For models where the generations are distributed across multiple curves we also present a motivation for the quark-lepton mass splittings at the GUT scale based on a Froggatt-Nielsen approach to flavour.
[ { "created": "Thu, 8 Jul 2010 06:41:46 GMT", "version": "v1" }, { "created": "Tue, 24 Aug 2010 04:58:57 GMT", "version": "v2" } ]
2014-11-21
[ [ "Dudas", "Emilian", "" ], [ "Palti", "Eran", "" ] ]
We study SU(5) Grand Unified Theories within a local framework in F-theory with multiple extra U(1) symmetries arising from a small monodromy group. The use of hypercharge flux for doublet-triplet splitting implies massless exotics in the spectrum that are protected from obtaining a mass by the U(1) symmetries. We find that lifting the exotics by giving vacuum expectation values to some GUT singlets spontaneously breaks all the U(1) symmetries which implies that proton decay operators are induced. If we impose an additional R-parity symmetry by hand we find all the exotics can be lifted while proton decay operators are still forbidden. These models can retain the gauge coupling unification accuracy of the MSSM at 1-loop. For models where the generations are distributed across multiple curves we also present a motivation for the quark-lepton mass splittings at the GUT scale based on a Froggatt-Nielsen approach to flavour.
1401.1447
Jose Rodriguez-Quintero
A. Bashir, A. Raya, J. Rodr\'iguez-Quintero
Dynamical quarks effects on the gluon propagation and chiral symmetry restoration
Contribution to QCD-TNT-III: "From quarks and gluons to hadronic matter: A bridge too far?"
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We exploit the recent lattice results for the infrared gluon propagator with light dynamical quarks and solve the gap equation for the quark propagator. Chiral symmetry breaking and confinement (intimately tied with the analytic properties of QCD Schwinger functions) order parameters are then studied.
[ { "created": "Tue, 7 Jan 2014 17:23:41 GMT", "version": "v1" } ]
2014-01-08
[ [ "Bashir", "A.", "" ], [ "Raya", "A.", "" ], [ "Rodríguez-Quintero", "J.", "" ] ]
We exploit the recent lattice results for the infrared gluon propagator with light dynamical quarks and solve the gap equation for the quark propagator. Chiral symmetry breaking and confinement (intimately tied with the analytic properties of QCD Schwinger functions) order parameters are then studied.
1804.01098
Pier Paolo Giardino
Hooman Davoudiasl and Pier Paolo Giardino
Variation of $\alpha$ from a Dark Matter Force
6 pages; 3 figures; V2: published version
Phys.Lett. B788 (2019) 270-273
10.1016/j.physletb.2018.11.041
null
hep-ph astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider a long range scalar force that mainly couples to dark matter and unstable Standard Model states, like the muon, with tiny strength. Probing this type of force would present a challenge to observations. We point out that the dependence of the induced background scalar field on dark matter number density can cause the mass of the unstable particles to have spatial and temporal variations. These variations, in turn, leave an imprint on the value of the fine structure constant $\alpha$, through threshold corrections, that could be detected in astronomical and cosmological measurements. Our mechanism can accommodate the mild preference of the Planck data for such a deviation, $(\alpha_{_{\rm CMB}}-\alpha_{\rm present})/\alpha_{\rm present} = (-3.6\pm 3.7)\times 10^{-3}$. In this case, the requisite parameters typically imply that violations of Equivalence Principle may be within reach of future experiments.
[ { "created": "Tue, 3 Apr 2018 18:00:01 GMT", "version": "v1" }, { "created": "Wed, 12 Dec 2018 11:13:47 GMT", "version": "v2" } ]
2018-12-13
[ [ "Davoudiasl", "Hooman", "" ], [ "Giardino", "Pier Paolo", "" ] ]
We consider a long range scalar force that mainly couples to dark matter and unstable Standard Model states, like the muon, with tiny strength. Probing this type of force would present a challenge to observations. We point out that the dependence of the induced background scalar field on dark matter number density can cause the mass of the unstable particles to have spatial and temporal variations. These variations, in turn, leave an imprint on the value of the fine structure constant $\alpha$, through threshold corrections, that could be detected in astronomical and cosmological measurements. Our mechanism can accommodate the mild preference of the Planck data for such a deviation, $(\alpha_{_{\rm CMB}}-\alpha_{\rm present})/\alpha_{\rm present} = (-3.6\pm 3.7)\times 10^{-3}$. In this case, the requisite parameters typically imply that violations of Equivalence Principle may be within reach of future experiments.
1604.03958
Robert Lasenby
Asimina Arvanitaki, Masha Baryakhtar, Savas Dimopoulos, Sergei Dubovsky, Robert Lasenby
Black Hole Mergers and the QCD Axion at Advanced LIGO
6 pages, 4 figures; matches version published in PRD
Phys. Rev. D 95, 043001 (2017)
10.1103/PhysRevD.95.043001
null
hep-ph astro-ph.HE gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In the next few years Advanced LIGO (aLIGO) may see gravitational waves (GWs) from thousands of black hole (BH) mergers. This marks the beginning of a new precision tool for physics. Here we show how to search for new physics beyond the standard model using this tool, in particular the QCD axion in the mass range ma ~ 10^-14 to 10^-10 eV. Axions (or any bosons) in this mass range cause rapidly rotating BHs to shed their spin into a large cloud of axions in atomic Bohr orbits around the BH, through the effect of superradiance (SR). This results in a gap in the mass vs. spin distribution of BHs when the BH size is comparable to the axion's Compton wavelength. By measuring the spin and mass of the merging objects observed at LIGO, we could verify the presence and shape of the gap in the BH distribution produced by the axion. The axion cloud can also be discovered through the GWs it radiates via axion annihilations or level transitions. A blind monochromatic GW search may reveal up to 10^5 BHs radiating through axion annihilations, at distinct frequencies within ~3% of $2 ma. Axion transitions probe heavier axions and may be observable in future GW observatories. The merger events are perfect candidates for a targeted GW search. If the final BH has high spin, a SR cloud may grow and emit monochromatic GWs from axion annihilations. We may observe the SR evolution in real time.
[ { "created": "Wed, 13 Apr 2016 20:08:19 GMT", "version": "v1" }, { "created": "Thu, 2 Mar 2017 06:18:19 GMT", "version": "v2" } ]
2017-03-03
[ [ "Arvanitaki", "Asimina", "" ], [ "Baryakhtar", "Masha", "" ], [ "Dimopoulos", "Savas", "" ], [ "Dubovsky", "Sergei", "" ], [ "Lasenby", "Robert", "" ] ]
In the next few years Advanced LIGO (aLIGO) may see gravitational waves (GWs) from thousands of black hole (BH) mergers. This marks the beginning of a new precision tool for physics. Here we show how to search for new physics beyond the standard model using this tool, in particular the QCD axion in the mass range ma ~ 10^-14 to 10^-10 eV. Axions (or any bosons) in this mass range cause rapidly rotating BHs to shed their spin into a large cloud of axions in atomic Bohr orbits around the BH, through the effect of superradiance (SR). This results in a gap in the mass vs. spin distribution of BHs when the BH size is comparable to the axion's Compton wavelength. By measuring the spin and mass of the merging objects observed at LIGO, we could verify the presence and shape of the gap in the BH distribution produced by the axion. The axion cloud can also be discovered through the GWs it radiates via axion annihilations or level transitions. A blind monochromatic GW search may reveal up to 10^5 BHs radiating through axion annihilations, at distinct frequencies within ~3% of $2 ma. Axion transitions probe heavier axions and may be observable in future GW observatories. The merger events are perfect candidates for a targeted GW search. If the final BH has high spin, a SR cloud may grow and emit monochromatic GWs from axion annihilations. We may observe the SR evolution in real time.
1001.1163
Feng Yuan
Stanley J. Brodsky, Barbara Pasquini, Bowen Xiao, Feng Yuan
Phases of Augmented Hadronic Light-Front Wave Functions
10 pages, 1 figure
Phys.Lett.B687:327-330,2010
10.1016/j.physletb.2010.03.049
SLAC-PUB-13874
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It is an important question whether the final/initial state gluonic interactions which lead to naive-time-reversal-odd single-spin asymmetries and diffraction at leading twist can be associated in a definite way with the light-front wave function hadronic eigensolutions of QCD. We use light-front time-ordered perturbation theory to obtain augmented light-front wave functions which contain an imaginary phase which depends on the choice of advanced or retarded boundary condition for the gauge potential in light-cone gauge. We apply this formalism to the wave functions of the valence Fock states of nucleons and pions, and show how this illuminates the factorization properties of naive-time-reversal-odd transverse momentum dependent observables which arise from rescattering. In particular, one calculates the identical leading-twist Sivers function from the overlap of augmented light-front wavefunctions that one obtains from explicit calculations of the single-spin asymmetry in semi-inclusive deep inelastic lepton-polarized nucleon scattering where the required phases come from the final-state rescattering of the struck quark with the nucleon spectators.
[ { "created": "Fri, 8 Jan 2010 06:28:50 GMT", "version": "v1" } ]
2014-11-20
[ [ "Brodsky", "Stanley J.", "" ], [ "Pasquini", "Barbara", "" ], [ "Xiao", "Bowen", "" ], [ "Yuan", "Feng", "" ] ]
It is an important question whether the final/initial state gluonic interactions which lead to naive-time-reversal-odd single-spin asymmetries and diffraction at leading twist can be associated in a definite way with the light-front wave function hadronic eigensolutions of QCD. We use light-front time-ordered perturbation theory to obtain augmented light-front wave functions which contain an imaginary phase which depends on the choice of advanced or retarded boundary condition for the gauge potential in light-cone gauge. We apply this formalism to the wave functions of the valence Fock states of nucleons and pions, and show how this illuminates the factorization properties of naive-time-reversal-odd transverse momentum dependent observables which arise from rescattering. In particular, one calculates the identical leading-twist Sivers function from the overlap of augmented light-front wavefunctions that one obtains from explicit calculations of the single-spin asymmetry in semi-inclusive deep inelastic lepton-polarized nucleon scattering where the required phases come from the final-state rescattering of the struck quark with the nucleon spectators.
hep-ph/9710385
Thorsten Feldmann
Thorsten Feldmann
The eta(c)-gamma Transition Form Factor
4 pages, incl. 3 figures, Contribution to 4th International Workshop on Progress in Heavy Quark Physics, Rostock, September 20-22,1997
null
null
WU-B 97/29
hep-ph
null
The eta(c)-gamma transition form factor is calculated within a perturbative approach. It is shown that the Q^2 dependence of the form factor is well determined in the region where experimental data is expected in the near future.
[ { "created": "Fri, 17 Oct 1997 09:40:09 GMT", "version": "v1" } ]
2007-05-23
[ [ "Feldmann", "Thorsten", "" ] ]
The eta(c)-gamma transition form factor is calculated within a perturbative approach. It is shown that the Q^2 dependence of the form factor is well determined in the region where experimental data is expected in the near future.
hep-ph/0406079
Takashi Shimomura
Kanji Fujii and Takashi Shimomura
Unified Approach to Neutrino Oscillation and Decay Probabilities of Neutrino-Source Hadrons
7 pages
null
null
null
hep-ph
null
In the framework of quantum field theory, we examine what physical implications are included in the expectation values of the flavor neutrino charges at the time $x^0$ with respesct to the state $\ket{\Psi(x^0)}$, which is taken so as to coincide with the neutrino source state such as a charged pion at the time $x^0_I$ ($< x^0$).
[ { "created": "Mon, 7 Jun 2004 14:27:14 GMT", "version": "v1" } ]
2007-05-23
[ [ "Fujii", "Kanji", "" ], [ "Shimomura", "Takashi", "" ] ]
In the framework of quantum field theory, we examine what physical implications are included in the expectation values of the flavor neutrino charges at the time $x^0$ with respesct to the state $\ket{\Psi(x^0)}$, which is taken so as to coincide with the neutrino source state such as a charged pion at the time $x^0_I$ ($< x^0$).
hep-ph/0610386
Zbigniew Was
Z. Was
Precision simulations with TAUOLA and PHOTOS
6 two-column pages, with respect to first version some misprints etc. are removed
Nucl.Phys.Proc.Suppl.169:16-21,2007
10.1016/j.nuclphysbps.2007.02.113
IFJPAN-IV-2006-8
hep-ph
null
The status of the Monte Carlo programs for the simulation of tau-lepton production and decay in high-energy accelerator experiments is reviewed. No significant changes in the organization of the programs were introduced since previous TAU conference, that is why we will concentrate on some physical topics: (i) For TAUOLA Monte Carlo generator of tau-lepton decays, simulation of five scalar final states based on the hadronic current became available for the first time. As an example, simple, but realistic current for final states: 2pi- pi+ 2pi0 nu_tau, pi- 4pi0 nu_tau and 3pi- 2pi+ nu_tau is presented. The current is installed into TAUOLA. (ii) For the PHOTOS Monte Carlo, which generates radiative corrections in arbirtary decays, new results on next to leading order corrections became available for some decay modes. The complete corrections were installed for leptonic Z and B decays into a pair of scalars. (iii) During conference discussions, the importance of checking the uncertainty of the overall normalization for KORALB and KKMC simulations was underlined. Necessary steps to check the uncertainty and to adjust the programs to Belle and BaBar conditions are also listed.
[ { "created": "Sat, 28 Oct 2006 20:52:39 GMT", "version": "v1" }, { "created": "Sat, 2 Dec 2006 16:41:54 GMT", "version": "v2" } ]
2008-11-26
[ [ "Was", "Z.", "" ] ]
The status of the Monte Carlo programs for the simulation of tau-lepton production and decay in high-energy accelerator experiments is reviewed. No significant changes in the organization of the programs were introduced since previous TAU conference, that is why we will concentrate on some physical topics: (i) For TAUOLA Monte Carlo generator of tau-lepton decays, simulation of five scalar final states based on the hadronic current became available for the first time. As an example, simple, but realistic current for final states: 2pi- pi+ 2pi0 nu_tau, pi- 4pi0 nu_tau and 3pi- 2pi+ nu_tau is presented. The current is installed into TAUOLA. (ii) For the PHOTOS Monte Carlo, which generates radiative corrections in arbirtary decays, new results on next to leading order corrections became available for some decay modes. The complete corrections were installed for leptonic Z and B decays into a pair of scalars. (iii) During conference discussions, the importance of checking the uncertainty of the overall normalization for KORALB and KKMC simulations was underlined. Necessary steps to check the uncertainty and to adjust the programs to Belle and BaBar conditions are also listed.
hep-ph/0204047
Andrei Belitsky
A.V. Belitsky
QCD evolution equations
15 pages, LaTeX, 4 figures; Talk given at the workshop on The Phenomenology of Large-N QCD, Tempe, AZ, January 9-11, 2002
null
10.1142/9789812776914_0012
null
hep-ph
null
We discuss QCD evolution equations for two and three particle correlation functions of quarks and gluon fields in a hadron which describe development of the momentum distribution of a parton system with a change of the wave length of a probe which resolves it. We show in a general case of two-particle correlators how the four-dimensional conformal algebra and the known pattern of conformal symmetry breaking in QCD can be used to solve the complicated mixing problem of local operators under renormalization and compute economically anomalous dimensions of quark and gluon composite operators. An extension of QCD to N = 1 super Yang-Mills theory and use of superconformal anomalies arising after quantization allows to derive non-trivial relations between the anomalous dimensions. For three-parton systems the conformal symmetry alone is not enough to solve the three-particle problem. We show that in milticolor limit of QCD there arises an extra conserved charge describing the solitonic motion of the system of particles. The problem admits a one-to-one correspondence with certain spin chain models which are exactly solvable.
[ { "created": "Thu, 4 Apr 2002 19:24:50 GMT", "version": "v1" }, { "created": "Tue, 9 Apr 2002 14:38:42 GMT", "version": "v2" } ]
2017-08-23
[ [ "Belitsky", "A. V.", "" ] ]
We discuss QCD evolution equations for two and three particle correlation functions of quarks and gluon fields in a hadron which describe development of the momentum distribution of a parton system with a change of the wave length of a probe which resolves it. We show in a general case of two-particle correlators how the four-dimensional conformal algebra and the known pattern of conformal symmetry breaking in QCD can be used to solve the complicated mixing problem of local operators under renormalization and compute economically anomalous dimensions of quark and gluon composite operators. An extension of QCD to N = 1 super Yang-Mills theory and use of superconformal anomalies arising after quantization allows to derive non-trivial relations between the anomalous dimensions. For three-parton systems the conformal symmetry alone is not enough to solve the three-particle problem. We show that in milticolor limit of QCD there arises an extra conserved charge describing the solitonic motion of the system of particles. The problem admits a one-to-one correspondence with certain spin chain models which are exactly solvable.
2112.09463
Juan M. Torres-Rincon
Juan M. Torres-Rincon
Chiral symmetry restoration with three chiral partners
10 pages (11 according to arxiv.org compiler), 6 figures. Contribution to the Proceedings of the XXXIII International Workshop on High Energy Physics "Hard Problems of Hadron Physics: Non-Perturbative QCD & Related Quests"
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
I discuss the masses of chiral partners in the context of chiral symmetry restoration at finite temperature. Using the Nambu-Jona-Lasinio model I first remind the usual situation where two mesons of opposed parity become degenerate above the chiral transition temperature. Then I consider an effective theory for D mesons where the positive parity companion presents a "double pole structure". In this case three different masses need to be analyzed as functions of the temperature. I suggest a possible restoration pattern at high temperatures when the back-reaction of the quark condensate is incorporated.
[ { "created": "Fri, 17 Dec 2021 11:58:51 GMT", "version": "v1" } ]
2021-12-20
[ [ "Torres-Rincon", "Juan M.", "" ] ]
I discuss the masses of chiral partners in the context of chiral symmetry restoration at finite temperature. Using the Nambu-Jona-Lasinio model I first remind the usual situation where two mesons of opposed parity become degenerate above the chiral transition temperature. Then I consider an effective theory for D mesons where the positive parity companion presents a "double pole structure". In this case three different masses need to be analyzed as functions of the temperature. I suggest a possible restoration pattern at high temperatures when the back-reaction of the quark condensate is incorporated.
1605.08039
Dorival Goncalves
Dorival Goncalves, Frank Krauss, Silvan Kuttimalai, Philipp Maierh\"ofer
Boosting invisible searches via $\boldsymbol{ZH}$: From the Higgs Boson to Dark Matter Simplified Models
10 pages, 9 figures
Phys. Rev. D 94, 053014 (2016)
10.1103/PhysRevD.94.053014
IPPP/16/50, FR-PHENO-2016-006
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Higgs boson production in association with a $Z$-boson at the LHC is analysed, both in the Standard Model and in Simplified Model extensions for Dark Matter. We focus on $H\rightarrow$invisibles searches and show that loop-induced components for both the signal and background present phenomenologically relevant contributions to the $\mathcal{BR}(H\rightarrow\textit{inv})$ limits. In addition, the constraining power of this channel to Simplified Models for Dark Matter with scalar and pseudo-scalar mediators $\phi$ and $A$ is discussed and compared with non-collider constraints. We find that with $100~fb^{-1}$ of LHC data, this channel provides competitive constraints to the non-collider bounds, for most of the parameter space we consider, bounding the universal Standard Model fermion-mediator strength at $g_v < 1$ for moderate masses in the range of ${100~\text{GeV}<m_{\phi/A}<400}$ GeV.
[ { "created": "Wed, 25 May 2016 20:00:00 GMT", "version": "v1" } ]
2016-10-05
[ [ "Goncalves", "Dorival", "" ], [ "Krauss", "Frank", "" ], [ "Kuttimalai", "Silvan", "" ], [ "Maierhöfer", "Philipp", "" ] ]
Higgs boson production in association with a $Z$-boson at the LHC is analysed, both in the Standard Model and in Simplified Model extensions for Dark Matter. We focus on $H\rightarrow$invisibles searches and show that loop-induced components for both the signal and background present phenomenologically relevant contributions to the $\mathcal{BR}(H\rightarrow\textit{inv})$ limits. In addition, the constraining power of this channel to Simplified Models for Dark Matter with scalar and pseudo-scalar mediators $\phi$ and $A$ is discussed and compared with non-collider constraints. We find that with $100~fb^{-1}$ of LHC data, this channel provides competitive constraints to the non-collider bounds, for most of the parameter space we consider, bounding the universal Standard Model fermion-mediator strength at $g_v < 1$ for moderate masses in the range of ${100~\text{GeV}<m_{\phi/A}<400}$ GeV.
hep-ph/9807527
Victor S. Fadin
V.S.Fadin
Next-to-Leading BFKL
5 pages, latex, Talk given at the International Conference "DIS98", April 4-8, Brussels, Belgium, 1998
null
null
Budker INP 98-56
hep-ph
null
The representation of the total cross section at high energy $\sqrt s$ in the next-to-leading $\ln s$ approximation is given with definition of the impact factors and explicit expression for the BFKL kernel. The estimate of the Pomeron intercept and the next-to-leading contributions to anomalous dimensions near $j=1$ are presented.
[ { "created": "Wed, 29 Jul 1998 03:50:16 GMT", "version": "v1" } ]
2007-05-23
[ [ "Fadin", "V. S.", "" ] ]
The representation of the total cross section at high energy $\sqrt s$ in the next-to-leading $\ln s$ approximation is given with definition of the impact factors and explicit expression for the BFKL kernel. The estimate of the Pomeron intercept and the next-to-leading contributions to anomalous dimensions near $j=1$ are presented.
hep-ph/0301248
Monoranjan Guchait
Subhendu Chakrabarti, Monoranjan Guchait, N. K. Mondal
Constraining top squark in R-parity violating SUSY model using existing Tevatron data
12 pages, 4 Figures, LateX, minor changes, few references added, version to appear in Physical Rev. D
Phys.Rev.D68:015005,2003
10.1103/PhysRevD.68.015005
null
hep-ph
null
Signal of lighter top squark has been looked for using Tevatron data in the di-electron plus di-jet channel. We find that the mass of the lighter top squark when it decays dominantly in the electron plus jet channel, can be ruled out up to 220 GeV at 95% C.L. using di-electron data. In the framework of R-parity breaking SUSY model we exclude relevant R-parity violating couplings for a range of top squark masses and other SUSY parameters. The bounds on R-parity violating couplings are very stringent for the parameter space where lighter top squark turns out to be the next to lightest supersymmetric particle.
[ { "created": "Tue, 28 Jan 2003 15:55:31 GMT", "version": "v1" }, { "created": "Thu, 24 Apr 2003 13:16:16 GMT", "version": "v2" } ]
2008-11-26
[ [ "Chakrabarti", "Subhendu", "" ], [ "Guchait", "Monoranjan", "" ], [ "Mondal", "N. K.", "" ] ]
Signal of lighter top squark has been looked for using Tevatron data in the di-electron plus di-jet channel. We find that the mass of the lighter top squark when it decays dominantly in the electron plus jet channel, can be ruled out up to 220 GeV at 95% C.L. using di-electron data. In the framework of R-parity breaking SUSY model we exclude relevant R-parity violating couplings for a range of top squark masses and other SUSY parameters. The bounds on R-parity violating couplings are very stringent for the parameter space where lighter top squark turns out to be the next to lightest supersymmetric particle.
2206.06617
Eduardo Folco Capossoli
Eduardo Folco Capossoli, Miguel Angel Mart\'in Contreras, Danning Li, Alfredo Vega, and Henrique Boschi-Filho
Fermionic DIS from a deformed string/gauge correspondence model
V1: 11 pages, 1 figure. Contribution to 19th International Conference on Hadron Spectroscopy and Structure (HADRON 2021) 26 July-1 August 2021. Mexico City, Mexico (C21-07-26.1)
Rev.Mex.Fis.Supl.3 (2022)3, 0308076
10.31349/SuplRevMexFis.3.0308076
null
hep-ph hep-th
http://creativecommons.org/licenses/by/4.0/
From a deformed AdS$_5$ space, we used the string/gauge duality to study the deep inelastic scattering for unpolarized fermions with spin 1/2, considering the large Bjorken $x$ parameter regime. Here, we also took into account an anomalous dimension of an operator which represents fermions at the boundary. From this analysis, we compute the corresponding structure functions, which are dependent on $x$ and on the photon virtuality $q$. The results achieved are in agreement with the experimental data.
[ { "created": "Tue, 14 Jun 2022 06:25:48 GMT", "version": "v1" } ]
2022-06-15
[ [ "Capossoli", "Eduardo Folco", "" ], [ "Contreras", "Miguel Angel Martín", "" ], [ "Li", "Danning", "" ], [ "Vega", "Alfredo", "" ], [ "Boschi-Filho", "Henrique", "" ] ]
From a deformed AdS$_5$ space, we used the string/gauge duality to study the deep inelastic scattering for unpolarized fermions with spin 1/2, considering the large Bjorken $x$ parameter regime. Here, we also took into account an anomalous dimension of an operator which represents fermions at the boundary. From this analysis, we compute the corresponding structure functions, which are dependent on $x$ and on the photon virtuality $q$. The results achieved are in agreement with the experimental data.
2108.11982
Carlo Marzo
Carlo Marzo
Ghost and Tachyon Free Propagation up to spin-3 in Lorentz Invariant Field Theories
Ancillary file provided with the new mixing operators connecting different spin/parity sectors. v2: added references and cosmetic-induced changes. Content unchanged. v3: matches published PRD version. Mixing operators are now added in the appendix. Some verbose comments removed, original content stressed, results unchanged
null
10.1103/PhysRevD.105.065017
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We complete the set of spin-projector operators for fields up to rank-3 by providing all operators connecting sectors with same spin and parity. In this way we can broaden the search for unitary and non-tachyonic particle propagation in quadratic lagrangian with inter-field mixing. We use the properties of projector algebra to reanalyze known theories and shed light towards new healthy ones. We do so with full control over the gauge constraints by working the form of the saturated propagator in an appropriate frame of reference.
[ { "created": "Thu, 26 Aug 2021 18:25:14 GMT", "version": "v1" }, { "created": "Mon, 20 Sep 2021 13:35:53 GMT", "version": "v2" }, { "created": "Sun, 27 Feb 2022 17:57:13 GMT", "version": "v3" } ]
2022-04-13
[ [ "Marzo", "Carlo", "" ] ]
We complete the set of spin-projector operators for fields up to rank-3 by providing all operators connecting sectors with same spin and parity. In this way we can broaden the search for unitary and non-tachyonic particle propagation in quadratic lagrangian with inter-field mixing. We use the properties of projector algebra to reanalyze known theories and shed light towards new healthy ones. We do so with full control over the gauge constraints by working the form of the saturated propagator in an appropriate frame of reference.
1201.3710
Saeed Uddin
Saeed Uddin, Waseem Bashir, Jan Shabir Ahmad and Riyaz Ahmad Bhat
Quark-hadron Phase Transition in Relativistic Mean-field Model
Pages 25, Figures 12
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We have studied the quark-hadron phase transition with RMFT motivated equation of state for a strongly interacting hadronic sector and lattice motivated equation of state for weakly interacting QGP sector. The interactions in hadronic sector are dominated by the exchange of scalar and vector mesons ({\sigma}_ {\sigma}, {\omega}, {\rho}, {\phi}) thereby allowing this phase to be modeled by the interacting baryonic, pionic and Kaonic fields. The pionic and Kaonic fields are incorporated on equal footing to baryonic field rather than including pions and Kaons as exchange particles only. The effect of interactions on quark-hadron phase transition curve was studied using Gibbs criteria for phase equilibrium. It was found that the first order quark hadron phase transition curve ends at a critical point, whose coordinates coincide with that of lattice gauge theory result involving lattice re-summation technique.
[ { "created": "Wed, 18 Jan 2012 07:03:27 GMT", "version": "v1" } ]
2012-01-19
[ [ "Uddin", "Saeed", "" ], [ "Bashir", "Waseem", "" ], [ "Ahmad", "Jan Shabir", "" ], [ "Bhat", "Riyaz Ahmad", "" ] ]
We have studied the quark-hadron phase transition with RMFT motivated equation of state for a strongly interacting hadronic sector and lattice motivated equation of state for weakly interacting QGP sector. The interactions in hadronic sector are dominated by the exchange of scalar and vector mesons ({\sigma}_ {\sigma}, {\omega}, {\rho}, {\phi}) thereby allowing this phase to be modeled by the interacting baryonic, pionic and Kaonic fields. The pionic and Kaonic fields are incorporated on equal footing to baryonic field rather than including pions and Kaons as exchange particles only. The effect of interactions on quark-hadron phase transition curve was studied using Gibbs criteria for phase equilibrium. It was found that the first order quark hadron phase transition curve ends at a critical point, whose coordinates coincide with that of lattice gauge theory result involving lattice re-summation technique.
hep-ph/9709435
null
S. Moretti and K. Odagiri (Cavendish Laboratory, Cambridge, UK)
Single-top production at future ep colliders
28 pages, latex, epsfig, 10 postscript figures, complete paper available at ftp://axpa.hep.phy.cam.ac.uk/moretti/cavendish_9704 and at http://www.hep.phy.cam.ac.uk/theory/papers/
Phys.Rev. D57 (1998) 3040-3050
10.1103/PhysRevD.57.3040
Cavendish-HEP-97/04
hep-ph
null
The production of top quarks in single mode at future ep colliders is studied, the attention being mainly focused to the case of the proposed LEPXLHC collider. We are motivated to reanalyse such a process following the discovery of the top quark at Fermilab. Thanks to the measurement of its mass one is now able to establish more accurately the relevance of single top production for itself and for many other processes to which it may act as a background. In addition, the recent improvement of our knowledge of the quark and gluon dynamics inside the proton now allows one to pin down the dependence of single top production on the partonic structure functions. Both the leptonic and hadronic decay channels of the top quark are studied and compared to the yield of the corresponding irreducible background in presence of b-tagging
[ { "created": "Tue, 23 Sep 1997 22:39:43 GMT", "version": "v1" } ]
2009-10-30
[ [ "Moretti", "S.", "", "Cavendish Laboratory, Cambridge, UK" ], [ "Odagiri", "K.", "", "Cavendish Laboratory, Cambridge, UK" ] ]
The production of top quarks in single mode at future ep colliders is studied, the attention being mainly focused to the case of the proposed LEPXLHC collider. We are motivated to reanalyse such a process following the discovery of the top quark at Fermilab. Thanks to the measurement of its mass one is now able to establish more accurately the relevance of single top production for itself and for many other processes to which it may act as a background. In addition, the recent improvement of our knowledge of the quark and gluon dynamics inside the proton now allows one to pin down the dependence of single top production on the partonic structure functions. Both the leptonic and hadronic decay channels of the top quark are studied and compared to the yield of the corresponding irreducible background in presence of b-tagging
1410.1384
Jose L. Goity
Ishara P. Fernando and Jose L. Goity
Baryon spin-flavor structure from an analysis of lattice QCD results of the baryon spectrum
35 pages, 5 figures
null
10.1103/PhysRevD.91.036005
JLAB-THY-14-1961
hep-ph hep-lat nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The excited baryon masses are analyzed in the framework of the $1/N_c$ expansion using the available physical masses and also the masses obtained in lattice QCD for different quark masses. The baryon states are organized into irreducible representations of $SU(6)\times O(3)$, where the $[{\bf{56}},\ell^P=0^+]$ ground state and excited baryons, and the $[{\bf{56}},2^+]$ and $[{\bf{70}},1^-]$ excited states are analyzed. The analyses are carried out to order 1/Nc and first order in the quark masses. The issue of state identifications is discussed. Numerous parameter independent mass relations result at those orders, among them the well known Gell-Mann-Okubo and Equal Spacing relations, as well as additional relations involving baryons with different spins. It is observed that such relations are satisfied at the expected level of precision. From the quark mass dependence of the coefficients in the baryon mass formulas an increasingly simpler picture of the spin-flavor composition of the baryons is observed with increasing quark masses, as measured by the number of significant mass operators.
[ { "created": "Mon, 6 Oct 2014 14:24:16 GMT", "version": "v1" } ]
2015-06-23
[ [ "Fernando", "Ishara P.", "" ], [ "Goity", "Jose L.", "" ] ]
The excited baryon masses are analyzed in the framework of the $1/N_c$ expansion using the available physical masses and also the masses obtained in lattice QCD for different quark masses. The baryon states are organized into irreducible representations of $SU(6)\times O(3)$, where the $[{\bf{56}},\ell^P=0^+]$ ground state and excited baryons, and the $[{\bf{56}},2^+]$ and $[{\bf{70}},1^-]$ excited states are analyzed. The analyses are carried out to order 1/Nc and first order in the quark masses. The issue of state identifications is discussed. Numerous parameter independent mass relations result at those orders, among them the well known Gell-Mann-Okubo and Equal Spacing relations, as well as additional relations involving baryons with different spins. It is observed that such relations are satisfied at the expected level of precision. From the quark mass dependence of the coefficients in the baryon mass formulas an increasingly simpler picture of the spin-flavor composition of the baryons is observed with increasing quark masses, as measured by the number of significant mass operators.
hep-ph/9801220
Gordon Chalmers
Gordon Chalmers and Warren Siegel
Simplifying Algebra in Feynman Graphs, Part II: Spinor Helicity from the Spacecone
18 pages, latex
Phys.Rev. D59 (1999) 045013
10.1103/PhysRevD.59.045013
ITP-SB-98-05
hep-ph hep-th
null
Manifestly Lorentz covariant Feynman rules are given in terms of a "scalar" field for each helicity, dramatically simplifying the calculation of amplitudes with massless particles. The spinor helicity formalism is properly identified as a null complex spacelike (not lightlike) gauge, where two massless external momenta define the reference frame. Usually this gauge is applied only to external line factors; we extend this method to vertices and propagators by modifying the action itself using lightcone methods.
[ { "created": "Mon, 5 Jan 1998 20:32:50 GMT", "version": "v1" } ]
2009-10-31
[ [ "Chalmers", "Gordon", "" ], [ "Siegel", "Warren", "" ] ]
Manifestly Lorentz covariant Feynman rules are given in terms of a "scalar" field for each helicity, dramatically simplifying the calculation of amplitudes with massless particles. The spinor helicity formalism is properly identified as a null complex spacelike (not lightlike) gauge, where two massless external momenta define the reference frame. Usually this gauge is applied only to external line factors; we extend this method to vertices and propagators by modifying the action itself using lightcone methods.
1703.02917
Dingli Hu
Dingli Hu, Tianjun Li, Adam Lux, James A. Maxin, Dimitri V. Nanopoulos
General No-Scale Supergravity: An ${\cal F}$-$SU(5)$ Tale
8 pages, 4 figures, 4 tables; Version accepted for publication in Physics Letters B
Physics Letters B771 (2017) 264-270
10.1016/j.physletb.2017.05.056
ACT-02-17, MI-TH-1747
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the grand unification model flipped $SU(5)$ with additional vector-like particle multiplets, or ${\cal F}$-$SU(5)$ for short, in the framework of General No-Scale Supergravity. In our analysis we allow the supersymmetry (SUSY) breaking soft terms to be generically non-zero, thereby extending the phenomenologically viable parameter space beyond the highly constrained one-parameter version of ${\cal F}$-$SU(5)$. In this initial inquiry, the mSUGRA/CMSSM SUSY breaking terms are implemented. We find this easing away from the vanishing SUSY breaking terms enables a more broad mass range of vector-like particles, dubbed flippons, including flippons less than 1 TeV that could presently be observed at the LHC2, as well as a lighter gluino mass and SUSY spectrum overall. This presents heightened odds that the General No-Scale ${\cal F}$-$SU(5)$ viable parameter space can be probed at the LHC2. The phenomenology comprises both bino and higgsino dark matter, including a Higgs funnel region. Particle states emerging from the SUSY cascade decays are presented to experimentally distinguish amongst the diverse phenomenological regions.
[ { "created": "Wed, 8 Mar 2017 17:07:01 GMT", "version": "v1" }, { "created": "Tue, 6 Jun 2017 01:13:58 GMT", "version": "v2" } ]
2017-06-07
[ [ "Hu", "Dingli", "" ], [ "Li", "Tianjun", "" ], [ "Lux", "Adam", "" ], [ "Maxin", "James A.", "" ], [ "Nanopoulos", "Dimitri V.", "" ] ]
We study the grand unification model flipped $SU(5)$ with additional vector-like particle multiplets, or ${\cal F}$-$SU(5)$ for short, in the framework of General No-Scale Supergravity. In our analysis we allow the supersymmetry (SUSY) breaking soft terms to be generically non-zero, thereby extending the phenomenologically viable parameter space beyond the highly constrained one-parameter version of ${\cal F}$-$SU(5)$. In this initial inquiry, the mSUGRA/CMSSM SUSY breaking terms are implemented. We find this easing away from the vanishing SUSY breaking terms enables a more broad mass range of vector-like particles, dubbed flippons, including flippons less than 1 TeV that could presently be observed at the LHC2, as well as a lighter gluino mass and SUSY spectrum overall. This presents heightened odds that the General No-Scale ${\cal F}$-$SU(5)$ viable parameter space can be probed at the LHC2. The phenomenology comprises both bino and higgsino dark matter, including a Higgs funnel region. Particle states emerging from the SUSY cascade decays are presented to experimentally distinguish amongst the diverse phenomenological regions.
2312.03672
Herschel A. Chawdhry
Herschel A. Chawdhry
p-adic reconstruction of rational functions in multi-loop amplitudes
11 pages
null
null
OUTP-23-14P
hep-ph hep-th
http://creativecommons.org/licenses/by-nc-sa/4.0/
Numerical reconstruction techniques are widely employed in the calculation of multi-loop scattering amplitudes. In recent years, it has been observed that the rational functions in multi-loop calculations greatly simplify under partial fractioning. In this article, we present a technique to reconstruct rational functions directly in partial-fractioned form, by evaluating the functions at special integer points chosen for their properties under a p-adic metric. As an application, we apply this technique to reconstruct the largest rational function in the integration-by-parts reduction of one of the rank-5 integrals appearing in 2-loop 5-point full-colour massless QCD amplitude calculations. The number of required numerical probes (per prime field) is found to be around 25 times smaller than in conventional techniques, and the obtained result is 130 times smaller. The reconstructed result displays signs of additional structure that could be used to further reduce its size and the number of required probes.
[ { "created": "Wed, 6 Dec 2023 18:37:51 GMT", "version": "v1" } ]
2023-12-07
[ [ "Chawdhry", "Herschel A.", "" ] ]
Numerical reconstruction techniques are widely employed in the calculation of multi-loop scattering amplitudes. In recent years, it has been observed that the rational functions in multi-loop calculations greatly simplify under partial fractioning. In this article, we present a technique to reconstruct rational functions directly in partial-fractioned form, by evaluating the functions at special integer points chosen for their properties under a p-adic metric. As an application, we apply this technique to reconstruct the largest rational function in the integration-by-parts reduction of one of the rank-5 integrals appearing in 2-loop 5-point full-colour massless QCD amplitude calculations. The number of required numerical probes (per prime field) is found to be around 25 times smaller than in conventional techniques, and the obtained result is 130 times smaller. The reconstructed result displays signs of additional structure that could be used to further reduce its size and the number of required probes.
1604.07358
Shreyashi Chakdar
Shreyashi Chakdar
New Physics at the TeV Scale
This is a PhD Dissertation in Particle physics Theory/Phenomenology
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Standard Model of particle physics is assumed to be a low-energy effective theory with new physics theoretically motivated to be around TeV scale. The dissertation presents theories with new physics beyond the Standard Model at the TeV scale testable in the current High Energy Colliders. The study on leptoquarks gauge bosons in reference to TopSU(5) model in chapter 2 showed that their discovery mass range extends upto 1.5 TeV at 14 TeV LHC with luminosity of 100 $fb^{-1}$. On the other hand, in chapter 3 we studied the collider phenomenology of TeV scale mirror fermions in Left-Right Mirror model finding that the reaches for the mirror quarks goes upto $750$ GeV at the $14$ TeV LHC with $~300 ~fb^{-1}$ luminosity. In chapter 4 we have enlarged the bosonic symmetry to fermi-bose symmetry e.g. supersymmetry and have shown that SUSY with non-universalities in gaugino or scalar masses within high scale SUGRA set up can still be accessible at LHC with 14 TeV. In chapter 5, we performed a study in respect to the $e^+e^-$ collider and find that precise measurements of the higgs boson mass splittings upto $\sim 100$ MeV may be possible with high luminosity in the International Linear Collider (ILC). In chapter 6 we have shown that the experimental data on neutrino masses and mixings are consistent with the proposed 4/5 parameter Dirac neutrino models yielding a solution for the neutrino masses with inverted mass hierarchy and large CP violating phase $\delta$ and thus can be tested experimentally. Chapter 7 incorporates a warm dark matter candidate in context of two Higgs doublet model. The model has several testable consequences at LHC. This dissertation presents an endeavor to study beyond standard model (BSM) physics at the TeV scale with testable signals in the Colliders.
[ { "created": "Mon, 25 Apr 2016 18:37:41 GMT", "version": "v1" } ]
2016-04-26
[ [ "Chakdar", "Shreyashi", "" ] ]
The Standard Model of particle physics is assumed to be a low-energy effective theory with new physics theoretically motivated to be around TeV scale. The dissertation presents theories with new physics beyond the Standard Model at the TeV scale testable in the current High Energy Colliders. The study on leptoquarks gauge bosons in reference to TopSU(5) model in chapter 2 showed that their discovery mass range extends upto 1.5 TeV at 14 TeV LHC with luminosity of 100 $fb^{-1}$. On the other hand, in chapter 3 we studied the collider phenomenology of TeV scale mirror fermions in Left-Right Mirror model finding that the reaches for the mirror quarks goes upto $750$ GeV at the $14$ TeV LHC with $~300 ~fb^{-1}$ luminosity. In chapter 4 we have enlarged the bosonic symmetry to fermi-bose symmetry e.g. supersymmetry and have shown that SUSY with non-universalities in gaugino or scalar masses within high scale SUGRA set up can still be accessible at LHC with 14 TeV. In chapter 5, we performed a study in respect to the $e^+e^-$ collider and find that precise measurements of the higgs boson mass splittings upto $\sim 100$ MeV may be possible with high luminosity in the International Linear Collider (ILC). In chapter 6 we have shown that the experimental data on neutrino masses and mixings are consistent with the proposed 4/5 parameter Dirac neutrino models yielding a solution for the neutrino masses with inverted mass hierarchy and large CP violating phase $\delta$ and thus can be tested experimentally. Chapter 7 incorporates a warm dark matter candidate in context of two Higgs doublet model. The model has several testable consequences at LHC. This dissertation presents an endeavor to study beyond standard model (BSM) physics at the TeV scale with testable signals in the Colliders.
hep-ph/9602224
Jun-ichi Kamoshita
J. Kamoshita(KEK), Y. Okada(KEK), M. Tanaka(Osaka) and I. Watanabe(Ochanomizu)
Studying the Higgs Potential via $e^+e^- \to Zhh$
10 pages, 7 figures included
null
null
KEK-TH-467, KEK Preprint 96-201, OCHA-PP-72, OU-HET 234
hep-ph
null
The physics prospect at future linear $e^+e^-$ colliders for the study of the Higgs triple self-coupling via the process of $e^+e^-$ $\rightarrow Zhh$ is investigated. The measurement of this cross section leads us to the first non-trivial information on the Higgs potential. We found that the Standard Model and the model without the Higgs self-coupling can be distinguished at the level of one standard deviation for a rather light Higgs mass with 100 fb$^{-1}$ integrated luminosity. In the MSSM, the cross section is enhanced if the production of at least one of heavy Higgs bosons ($H$ or $A$) and its subsequent decay ($H \rightarrow hh$, $A \rightarrow Zh$) are kinematically allowed. When such processes are not allowed, the cross section in the region of small $m_A$ is significantly suppressed relative to the SM cross section.
[ { "created": "Mon, 5 Feb 1996 12:58:27 GMT", "version": "v1" } ]
2007-05-23
[ [ "Kamoshita", "J.", "", "KEK" ], [ "Okada", "Y.", "", "KEK" ], [ "Tanaka", "M.", "", "Osaka" ], [ "Watanabe", "I.", "", "Ochanomizu" ] ]
The physics prospect at future linear $e^+e^-$ colliders for the study of the Higgs triple self-coupling via the process of $e^+e^-$ $\rightarrow Zhh$ is investigated. The measurement of this cross section leads us to the first non-trivial information on the Higgs potential. We found that the Standard Model and the model without the Higgs self-coupling can be distinguished at the level of one standard deviation for a rather light Higgs mass with 100 fb$^{-1}$ integrated luminosity. In the MSSM, the cross section is enhanced if the production of at least one of heavy Higgs bosons ($H$ or $A$) and its subsequent decay ($H \rightarrow hh$, $A \rightarrow Zh$) are kinematically allowed. When such processes are not allowed, the cross section in the region of small $m_A$ is significantly suppressed relative to the SM cross section.
1902.06723
Paolo Parotto
J. Noronha-Hostler, P. Parotto, C. Ratti, J. M. Stafford
Lattice-based equation of state at finite baryon number, electric charge and strangeness chemical potentials
14 pages, 6 figures; version published in Phys.Rev.C; clarified discussion of range of validity, added treatment of the speed of sound
Phys. Rev. C 100, 064910 (2019)
10.1103/PhysRevC.100.064910
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We construct an equation of state for Quantum Chromodynamics (QCD) at finite temperature and chemical potentials for baryon number $B$, electric charge $Q$ and strangeness $S$. We use the Taylor expansion method, up to the fourth power for the chemical potentials. This requires the knowledge of all diagonal and non-diagonal $BQS$ correlators up to fourth order: these results recently became available from lattice QCD simulations, albeit only at a finite lattice spacing $N_t=12$. We smoothly merge these results to the Hadron Resonance Gas (HRG) model, to be able to reach temperatures as low as 30 MeV; in the high temperature regime, we impose a smooth approach to the Stefan-Boltzmann limit. We provide a parameterization for each one of these $BQS$ correlators as functions of the temperature. We then calculate pressure, energy density, entropy density, baryonic, strangeness, electric charge densities and compare the two cases of strangeness neutrality and $\mu_S=\mu_Q=0$. We also calculate the isentropic trajectories and compare them in the two cases. Our equation of state can be readily used as an input of hydrodynamical simulations of matter created at the Relativistic Heavy Ion Collider (RHIC).
[ { "created": "Mon, 18 Feb 2019 18:50:53 GMT", "version": "v1" }, { "created": "Wed, 22 Jan 2020 14:31:38 GMT", "version": "v2" } ]
2020-01-23
[ [ "Noronha-Hostler", "J.", "" ], [ "Parotto", "P.", "" ], [ "Ratti", "C.", "" ], [ "Stafford", "J. M.", "" ] ]
We construct an equation of state for Quantum Chromodynamics (QCD) at finite temperature and chemical potentials for baryon number $B$, electric charge $Q$ and strangeness $S$. We use the Taylor expansion method, up to the fourth power for the chemical potentials. This requires the knowledge of all diagonal and non-diagonal $BQS$ correlators up to fourth order: these results recently became available from lattice QCD simulations, albeit only at a finite lattice spacing $N_t=12$. We smoothly merge these results to the Hadron Resonance Gas (HRG) model, to be able to reach temperatures as low as 30 MeV; in the high temperature regime, we impose a smooth approach to the Stefan-Boltzmann limit. We provide a parameterization for each one of these $BQS$ correlators as functions of the temperature. We then calculate pressure, energy density, entropy density, baryonic, strangeness, electric charge densities and compare the two cases of strangeness neutrality and $\mu_S=\mu_Q=0$. We also calculate the isentropic trajectories and compare them in the two cases. Our equation of state can be readily used as an input of hydrodynamical simulations of matter created at the Relativistic Heavy Ion Collider (RHIC).
1312.7664
Manan N. Shah
Manan Shah, Kaushal Thakkar, Arpit Parmar and P C Vinodkumar
Status of $\psi$ (3686), $\psi$ (4040), $\psi$ (4160), Y (4260), $\psi $ (4415) and X (4630) charmonia like states
null
null
null
null
hep-ph
http://creativecommons.org/licenses/by/3.0/
We examine the status of charmonia like states by looking into the behaviour of the energy level differences and regularity in the behaviour of the leptonic decay widths of the excited charmonia states. The spectroscopic states are studied using a phenomenological Martin-like confinement potential and their radial wave functions are employed to compute the di-leptonic decay widths. Their deviations from the expected behaviour provide a clue to consider them as admixtures of the nearby S and D states. The present analysis strongly favour \$$\backslash$psi \$ (3686) as admixture of $c \bar{c}$ (2S) and $c \bar{c}$g (4.1 GeV) hybrid, \$$\backslash$psi \$ (4040) and \$$\backslash$psi \$ (4160) as admixture states of charmonia (3S, 3D) states with mixing angle \$$\backslash$theta \$ = 11$^\circ$ and 45$^\circ$ respectively. We identify Y (4260) as a pure $c \bar{c}$ (4S) state whose leptonic decay is predicted as 0.65 keV. While X(4630) is closer to the $c \bar{c}$ (6S) state. The status of \$$\backslash$psi \$ (4415) is still not clear as it does not fit to be pure or admixture state.
[ { "created": "Mon, 30 Dec 2013 09:32:48 GMT", "version": "v1" } ]
2013-12-31
[ [ "Shah", "Manan", "" ], [ "Thakkar", "Kaushal", "" ], [ "Parmar", "Arpit", "" ], [ "Vinodkumar", "P C", "" ] ]
We examine the status of charmonia like states by looking into the behaviour of the energy level differences and regularity in the behaviour of the leptonic decay widths of the excited charmonia states. The spectroscopic states are studied using a phenomenological Martin-like confinement potential and their radial wave functions are employed to compute the di-leptonic decay widths. Their deviations from the expected behaviour provide a clue to consider them as admixtures of the nearby S and D states. The present analysis strongly favour \$$\backslash$psi \$ (3686) as admixture of $c \bar{c}$ (2S) and $c \bar{c}$g (4.1 GeV) hybrid, \$$\backslash$psi \$ (4040) and \$$\backslash$psi \$ (4160) as admixture states of charmonia (3S, 3D) states with mixing angle \$$\backslash$theta \$ = 11$^\circ$ and 45$^\circ$ respectively. We identify Y (4260) as a pure $c \bar{c}$ (4S) state whose leptonic decay is predicted as 0.65 keV. While X(4630) is closer to the $c \bar{c}$ (6S) state. The status of \$$\backslash$psi \$ (4415) is still not clear as it does not fit to be pure or admixture state.
1709.07058
Oleg Tarasov
O. V. Tarasov
Methods for deriving functional equations for Feynman integrals
11 pages, 2 figures, PdfLatex
null
10.1088/1742-6596/920/1/012004
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present short review of two methods for obtaining functional equations for Feynman integrals. Application of these methods for finding functional equations for one- and two- loop integrals is described in detail. It is shown that with the aid of functional equations Feynman integrals in general kinematics can be expressed in terms of simpler integrals. Similarities between functional equations for Feynman integrals and addition theorem for Abel integrals are shortly discussed.
[ { "created": "Wed, 20 Sep 2017 20:03:15 GMT", "version": "v1" } ]
2017-11-22
[ [ "Tarasov", "O. V.", "" ] ]
We present short review of two methods for obtaining functional equations for Feynman integrals. Application of these methods for finding functional equations for one- and two- loop integrals is described in detail. It is shown that with the aid of functional equations Feynman integrals in general kinematics can be expressed in terms of simpler integrals. Similarities between functional equations for Feynman integrals and addition theorem for Abel integrals are shortly discussed.
1608.02946
Carlos Arguelles Delgado
C.A. Arg\"uelles, G.H. Collin, J.M. Conrad, T. Katori, A. Kheirandish
Search for Lorentz Violation in km$^3$-Scale Neutrino Telescopes
Presented at the Seventh Meeting on CPT and Lorentz Symmetry, Bloomington, Indiana, June 20-24, 2016
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Kilometer$^3$-scale neutrino detectors such as IceCube, ANTARES, and the proposed Km3Net neutrino observatory in the Mediterranean have measured, and will continue to characterize, the atmospheric neutrino spectrum above 1 TeV. Such precise measurements enable us to probe new neutrino physics, in particular, those that arise from Lorentz violation. In this paper, we first relate the effective new physics hamiltonian terms with the Lorentz violating literature. Second, we calculate the oscillation probability formulas for the two-level $\nu_\mu-\nu_\tau$ sector. Finally, we comment on some of the challenges and outlook for this analysis.
[ { "created": "Tue, 9 Aug 2016 20:00:05 GMT", "version": "v1" } ]
2016-08-11
[ [ "Argüelles", "C. A.", "" ], [ "Collin", "G. H.", "" ], [ "Conrad", "J. M.", "" ], [ "Katori", "T.", "" ], [ "Kheirandish", "A.", "" ] ]
Kilometer$^3$-scale neutrino detectors such as IceCube, ANTARES, and the proposed Km3Net neutrino observatory in the Mediterranean have measured, and will continue to characterize, the atmospheric neutrino spectrum above 1 TeV. Such precise measurements enable us to probe new neutrino physics, in particular, those that arise from Lorentz violation. In this paper, we first relate the effective new physics hamiltonian terms with the Lorentz violating literature. Second, we calculate the oscillation probability formulas for the two-level $\nu_\mu-\nu_\tau$ sector. Finally, we comment on some of the challenges and outlook for this analysis.
hep-ph/9803365
null
H. Burkhardt, J. Lowe, G.J. Stephenson Jr., T. Goldman
Oscillations of recoil particles against mixed states
Several minor errors corrected and changes resulting from referee's comments included. Accepted for publication in Phys. Rev. D. Standard Latex
Phys.Rev.D59:054018,1999
10.1103/PhysRevD.59.054018
null
hep-ph nucl-th
null
Some consequences of the oscillations of neutral kaons and neutrinos are discussed, in particular, the possibility of oscillations of particles recoiling against kaons or neutrinos from the production process. We show that there are no stationary oscillations of these recoil particles in any order, and that the apparent long-wavelength oscillations, which might appear to result when an earlier treatment of ours was taken to higher order, are spurious. We show that the recoil particles may show a travelling interference pattern. It may be possible to observe this pattern for $\Lambda$s produced in a reaction, but there seems to be little hope of observing this for the case of neutrinos from muon decay.
[ { "created": "Mon, 16 Mar 1998 22:58:11 GMT", "version": "v1" }, { "created": "Thu, 31 Dec 1998 10:16:54 GMT", "version": "v2" } ]
2008-11-26
[ [ "Burkhardt", "H.", "" ], [ "Lowe", "J.", "" ], [ "Stephenson", "G. J.", "Jr." ], [ "Goldman", "T.", "" ] ]
Some consequences of the oscillations of neutral kaons and neutrinos are discussed, in particular, the possibility of oscillations of particles recoiling against kaons or neutrinos from the production process. We show that there are no stationary oscillations of these recoil particles in any order, and that the apparent long-wavelength oscillations, which might appear to result when an earlier treatment of ours was taken to higher order, are spurious. We show that the recoil particles may show a travelling interference pattern. It may be possible to observe this pattern for $\Lambda$s produced in a reaction, but there seems to be little hope of observing this for the case of neutrinos from muon decay.
1808.06233
Artem Lipatov
S.P. Baranov, A.V. Lipatov, M.A. Malyshev
Associated non-prompt $J/\psi + \mu$ and $J/\psi + J/\psi$ production at LHC as a test for TMD gluon density
14 pages, 12 figures
Eur. Phys. J. C 78, 820 (2018)
10.1140/epjc/s10052-018-6297-8
DESY 18-138
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider the associated production of $J/\psi$ mesons and muons originating from the $b$-flavored hadron decays and non-prompt double $J/\psi$ production at the LHC using the $k_T$-factorization approach. To describe the inclusive $b$-hadron decays into the different charmonium states we apply fragmentation approach and adopt fragmentation functions based on the non-relativistic QCD factorization. The transverse momentum dependent (TMD) gluon densities in a proton are determined using the Catani-Ciafaloni-Fiorani-Marchesini equation and Kimber-Martin-Ryskin prescription. We investigate the effects coming from parton showers, estimate the double parton scattering contribution and compare our predictions with the first experimental data taken by the ATLAS and LHCb Collaborations at $\sqrt s = 8$~TeV. These data can serve as an additional test for TMD gluon density function in a proton.
[ { "created": "Sun, 19 Aug 2018 17:47:38 GMT", "version": "v1" } ]
2018-11-14
[ [ "Baranov", "S. P.", "" ], [ "Lipatov", "A. V.", "" ], [ "Malyshev", "M. A.", "" ] ]
We consider the associated production of $J/\psi$ mesons and muons originating from the $b$-flavored hadron decays and non-prompt double $J/\psi$ production at the LHC using the $k_T$-factorization approach. To describe the inclusive $b$-hadron decays into the different charmonium states we apply fragmentation approach and adopt fragmentation functions based on the non-relativistic QCD factorization. The transverse momentum dependent (TMD) gluon densities in a proton are determined using the Catani-Ciafaloni-Fiorani-Marchesini equation and Kimber-Martin-Ryskin prescription. We investigate the effects coming from parton showers, estimate the double parton scattering contribution and compare our predictions with the first experimental data taken by the ATLAS and LHCb Collaborations at $\sqrt s = 8$~TeV. These data can serve as an additional test for TMD gluon density function in a proton.
1608.08410
Marco Traini
Marco Claudio Traini
Generalized Parton Distributions: confining potential effects within AdS/QCD
16 pages, 11 figures, major revision, title changed, new sections included, figures added, new references, version accepted for publication in EPJ C
Eur. Phys. J. C (2017) 77:246
10.1140/epjc/s10052-017-4775-z
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Generalized Parton Distributions are investigated within a holographic approach where the string modes in the fifth dimension describe the nucleon in a bottom-up or AdS/QCD framework. The aim is to bring the AdS/QCD results in the realm of phenomenology in order to extract consequences and previsions. Two main aspects are studied: i) the role of the confining potential needed for breaking conformal invariance and introducing confinement (both: classic Soft-Wall and recent Infra-Red potentials are investigated); ii) the extension of the predicted GPDs to the entire range of off-forward kinematics by means of Double-Distributions. Higher Fock states are included describing the nucleon as a superposition of three valence quarks and quark-antiquark pairs and gluons.
[ { "created": "Tue, 30 Aug 2016 11:52:43 GMT", "version": "v1" }, { "created": "Tue, 6 Sep 2016 12:40:04 GMT", "version": "v2" }, { "created": "Wed, 22 Mar 2017 09:09:43 GMT", "version": "v3" } ]
2017-04-25
[ [ "Traini", "Marco Claudio", "" ] ]
Generalized Parton Distributions are investigated within a holographic approach where the string modes in the fifth dimension describe the nucleon in a bottom-up or AdS/QCD framework. The aim is to bring the AdS/QCD results in the realm of phenomenology in order to extract consequences and previsions. Two main aspects are studied: i) the role of the confining potential needed for breaking conformal invariance and introducing confinement (both: classic Soft-Wall and recent Infra-Red potentials are investigated); ii) the extension of the predicted GPDs to the entire range of off-forward kinematics by means of Double-Distributions. Higher Fock states are included describing the nucleon as a superposition of three valence quarks and quark-antiquark pairs and gluons.
2212.12075
Darius Jurciukonis
Duarte Fontes, Darius Jur\v{c}iukonis and Lu\'is Lavoura
The $Z b \bar b$ vertex in a left-right model
57 pages, 8 figures; v2: added section 3, figure 2 and three references; v3: matches published version
Nucl.Phys.B 996 (2023) 116373
10.1016/j.nuclphysb.2023.116373
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider the one-loop corrections to the $Z b \bar b$ vertex in a $CP$-conserving left--right model (LRM), $viz$. a model with gauge group $SU(2)_L \times SU(2)_R \times U(1)$. We allow the gauge coupling constants of $SU(2)_L$ and $SU(2)_R$ to be different. The spontaneous symmetry breaking is accomplished only by doublets and/or singlets of $SU(2)_L$ and $SU(2)_R$. The lightest massive neutral gauge boson of our LRM is assumed to have the same Yukawa couplings to bottom-quark pairs as the $Z$ of the Standard Model (SM); this assumption has the advantage that, then, the infrared divergences automatically cancel down in the subtraction of the $Z b \bar b$ vertex in the SM from the same vertex in the LRM. We effect a proper renormalization of the $Z b \bar b$ vertex and check explicitly both its gauge invariance and the cancellation of all the ultraviolet divergences. We find out that a LRM with the above assumptions cannot achieve a better fit to the $Z b \bar b$ vertex than a multi-Higgs extension of the SM, $viz$. both models can only achieve a decent fit when one admits scalar particles with very low masses $\lesssim 50$ GeV. This is true even when we allow for markedly different gauge coupling constants of $SU(2)_L$ and $SU(2)_R$.
[ { "created": "Thu, 22 Dec 2022 23:12:00 GMT", "version": "v1" }, { "created": "Wed, 8 Mar 2023 19:32:33 GMT", "version": "v2" }, { "created": "Sat, 21 Oct 2023 17:08:22 GMT", "version": "v3" } ]
2023-10-24
[ [ "Fontes", "Duarte", "" ], [ "Jurčiukonis", "Darius", "" ], [ "Lavoura", "Luís", "" ] ]
We consider the one-loop corrections to the $Z b \bar b$ vertex in a $CP$-conserving left--right model (LRM), $viz$. a model with gauge group $SU(2)_L \times SU(2)_R \times U(1)$. We allow the gauge coupling constants of $SU(2)_L$ and $SU(2)_R$ to be different. The spontaneous symmetry breaking is accomplished only by doublets and/or singlets of $SU(2)_L$ and $SU(2)_R$. The lightest massive neutral gauge boson of our LRM is assumed to have the same Yukawa couplings to bottom-quark pairs as the $Z$ of the Standard Model (SM); this assumption has the advantage that, then, the infrared divergences automatically cancel down in the subtraction of the $Z b \bar b$ vertex in the SM from the same vertex in the LRM. We effect a proper renormalization of the $Z b \bar b$ vertex and check explicitly both its gauge invariance and the cancellation of all the ultraviolet divergences. We find out that a LRM with the above assumptions cannot achieve a better fit to the $Z b \bar b$ vertex than a multi-Higgs extension of the SM, $viz$. both models can only achieve a decent fit when one admits scalar particles with very low masses $\lesssim 50$ GeV. This is true even when we allow for markedly different gauge coupling constants of $SU(2)_L$ and $SU(2)_R$.
2103.11877
V. E. Troitsky
S.V. Troitsky and V.E. Troitsky
K0 and K+ meson electromagnetic form factors: a nonperturbative relativistic quark model versus experimental, perturbative and lattice Quantum-Chromodynamics results
7 pages, 5 figures. V2: updated uncertainty in the quark anomalous magnetic moment; version accepted by Phys. Rev. D
Phys. Rev. D 104, 034015 (2021)
10.1103/PhysRevD.104.034015
INR-TH-2021-005
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It has been previously shown that a particular nonperturbative constituent-quark model of hadrons describes experimental measurements of electromagnetic form factors of light charged mesons through a small number of common phenomenological parameters, matching at the same time the Quantum-Chromodynamics (QCD) asymptotics for the pi-meson form factor at large momentum transfer. Here we start with the determination of the K0 electromagnetic form factor in this approach. Precise measurement of the K0 charge radius makes it possible to constrain model parameters with high accuracy. Then, with all parameters fixed, we revisit the K+ form factor and find that it matches experimental measurements in the infrared, lattice results at moderate momentum transfer and the perturbative QCD asymptotics in the ultraviolet. In this way we obtain a narrow constraint on the K+ charge radius, <r_K+^2> = 0.403 +0.007 -0.006 fm^2, and extend the successful infrared-ultraviolet connection from pi to K mesons.
[ { "created": "Mon, 22 Mar 2021 14:11:06 GMT", "version": "v1" }, { "created": "Fri, 30 Jul 2021 09:03:18 GMT", "version": "v2" } ]
2021-08-25
[ [ "Troitsky", "S. V.", "" ], [ "Troitsky", "V. E.", "" ] ]
It has been previously shown that a particular nonperturbative constituent-quark model of hadrons describes experimental measurements of electromagnetic form factors of light charged mesons through a small number of common phenomenological parameters, matching at the same time the Quantum-Chromodynamics (QCD) asymptotics for the pi-meson form factor at large momentum transfer. Here we start with the determination of the K0 electromagnetic form factor in this approach. Precise measurement of the K0 charge radius makes it possible to constrain model parameters with high accuracy. Then, with all parameters fixed, we revisit the K+ form factor and find that it matches experimental measurements in the infrared, lattice results at moderate momentum transfer and the perturbative QCD asymptotics in the ultraviolet. In this way we obtain a narrow constraint on the K+ charge radius, <r_K+^2> = 0.403 +0.007 -0.006 fm^2, and extend the successful infrared-ultraviolet connection from pi to K mesons.
2111.12307
Wen-Fei Wang
Wen-Fei Wang
Subprocesses $\rho(770,1450)\to K\bar{K}$ for the three-body hadronic $D$ meson decays
10 pages, 3 figures, accepted for publication in Phys.Rev.D
Phys. Rev. D 104, 116019 (2021)
10.1103/PhysRevD.104.116019
null
hep-ph hep-ex
http://creativecommons.org/licenses/by-nc-nd/4.0/
We construct the theoretical framework for quasi-two-body $D$ meson decays with the help of pion and kaon electromagnetic form factors, and with which we study the contributions of the subprocesses $\rho(770,1450)\to K\bar{K}$ for the three-body $D$ decays within the flavour $SU(3)$ symmetry. Because of the limitations imposed by phase space and strong coupling, the contributions for kaon pair from the virtual bound state $\rho(770)$ are channel-dependent and generally small for the concerned three-body $D$ decays. But some quasi-two-body processes could still be observed in the Dalitz plot analyses for related decays, such as $D^0 \to K^-\rho(770)^+ \to K^- K^+K_S^0$ and $D^+ \to K_S^0\rho(770)^+ \to K_S^0 K^+K_S^0$, they are predicted to have the branching fractions $\mathcal{B}=(0.82\pm0.04)\times 10^{-4}$ and $\mathcal{B}=0.47^{+0.05}_{-0.03}\times 10^{-4}$, which are $(1.86\pm0.16)\%$ and $(1.84^{+0.21}_{-0.16})\%$, respectively, of the total branching fractions for the corresponding three-body $D$ decays. We find in this work that the normal subprocesses like $\rho(1450)^+\to \pi^+\pi^0$ or $\rho(1450)^+\to K^+\bar{K}^0$, which are bound by the masses of decaying initial states, will provide virtual contributions in some special decays.
[ { "created": "Wed, 24 Nov 2021 07:15:54 GMT", "version": "v1" }, { "created": "Thu, 2 Dec 2021 14:59:03 GMT", "version": "v2" }, { "created": "Wed, 22 Dec 2021 09:13:12 GMT", "version": "v3" } ]
2021-12-23
[ [ "Wang", "Wen-Fei", "" ] ]
We construct the theoretical framework for quasi-two-body $D$ meson decays with the help of pion and kaon electromagnetic form factors, and with which we study the contributions of the subprocesses $\rho(770,1450)\to K\bar{K}$ for the three-body $D$ decays within the flavour $SU(3)$ symmetry. Because of the limitations imposed by phase space and strong coupling, the contributions for kaon pair from the virtual bound state $\rho(770)$ are channel-dependent and generally small for the concerned three-body $D$ decays. But some quasi-two-body processes could still be observed in the Dalitz plot analyses for related decays, such as $D^0 \to K^-\rho(770)^+ \to K^- K^+K_S^0$ and $D^+ \to K_S^0\rho(770)^+ \to K_S^0 K^+K_S^0$, they are predicted to have the branching fractions $\mathcal{B}=(0.82\pm0.04)\times 10^{-4}$ and $\mathcal{B}=0.47^{+0.05}_{-0.03}\times 10^{-4}$, which are $(1.86\pm0.16)\%$ and $(1.84^{+0.21}_{-0.16})\%$, respectively, of the total branching fractions for the corresponding three-body $D$ decays. We find in this work that the normal subprocesses like $\rho(1450)^+\to \pi^+\pi^0$ or $\rho(1450)^+\to K^+\bar{K}^0$, which are bound by the masses of decaying initial states, will provide virtual contributions in some special decays.
hep-ph/0503126
Peihong Gu
Pei-Hong Gu and Hong Mao
Constraint on $B-L$ cosmic string from leptogenesis with degenerate neutrinos
12 pages, 3 figures; revised version, accepted for publication in Phys. Lett. B
Phys.Lett. B619 (2005) 226-232
10.1016/j.physletb.2005.05.053
null
hep-ph
null
In the early Universe, as a consequence of $U(1)_{B-L}$ gauge symmetry-breaking, the so-called $B-L$ cosmic strings are expected to be produced at the breaking scale $\eta_{B-L}$ according to the Kibble mechanism. The decaying, collapsing closed loops of these strings can release the right-handed neutrinos, whose subsequent decay can contribute to the baryon asymmetry of the Universe (BAU), through the "slow death"(SD) process and/or the "quick death"(QD) process. In this paper, we assume that the decay of the lightest heavy Majorana neutrinos released from the $B-L$ cosmic string loops can produce a baryon asymmetry consistent with the cosmic microwave background (CMB) observations. Considering the fact that both the neutrinoless double beta decay experiment and the cosmological data show a preference for degenerate neutrinos, we give the lower limits for the breaking scale $\eta_{B-L}$ with the neutrino masses $0.06 eV \leq \bar{m}=(m_{1}^{2}+m_{2}^{2}+m_{3}^{2})^{1/2} \leq 1.0 eV$, where the full possible cases of degenerate neutrinos are included. We obtain $\eta_{B-L}\gtrsim 3.3 \times 10^{15} GeV$, $5.3 \times 10^{15} GeV$ and $9.5 \times 10^{15} GeV$ for $\bar{m}=0.2 eV$, $0.4 eV$ and $1.0 eV$ respectively in the SD process, and find the $B-L$ cosmic string has a very small contribution to the BAU in the QD process.
[ { "created": "Mon, 14 Mar 2005 15:26:44 GMT", "version": "v1" }, { "created": "Mon, 23 May 2005 08:16:59 GMT", "version": "v2" } ]
2009-11-11
[ [ "Gu", "Pei-Hong", "" ], [ "Mao", "Hong", "" ] ]
In the early Universe, as a consequence of $U(1)_{B-L}$ gauge symmetry-breaking, the so-called $B-L$ cosmic strings are expected to be produced at the breaking scale $\eta_{B-L}$ according to the Kibble mechanism. The decaying, collapsing closed loops of these strings can release the right-handed neutrinos, whose subsequent decay can contribute to the baryon asymmetry of the Universe (BAU), through the "slow death"(SD) process and/or the "quick death"(QD) process. In this paper, we assume that the decay of the lightest heavy Majorana neutrinos released from the $B-L$ cosmic string loops can produce a baryon asymmetry consistent with the cosmic microwave background (CMB) observations. Considering the fact that both the neutrinoless double beta decay experiment and the cosmological data show a preference for degenerate neutrinos, we give the lower limits for the breaking scale $\eta_{B-L}$ with the neutrino masses $0.06 eV \leq \bar{m}=(m_{1}^{2}+m_{2}^{2}+m_{3}^{2})^{1/2} \leq 1.0 eV$, where the full possible cases of degenerate neutrinos are included. We obtain $\eta_{B-L}\gtrsim 3.3 \times 10^{15} GeV$, $5.3 \times 10^{15} GeV$ and $9.5 \times 10^{15} GeV$ for $\bar{m}=0.2 eV$, $0.4 eV$ and $1.0 eV$ respectively in the SD process, and find the $B-L$ cosmic string has a very small contribution to the BAU in the QD process.
2301.00728
Andrew Akeroyd
A.G. Akeroyd, S. Alanazi, Stefano Moretti
The decay $A^0\to h^0 Z^{(*)}$ in the inverted hierarchy scenario and its detection prospects at the Large Hadron Collider
35 pages, 8 figures
null
10.1088/1361-6471/ace3e1
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
Searches are being carried out at the Large Hadron Collider (LHC) for the decay of the CP-odd scalar ($A^0$) in Two-Higgs-Doublet Models (2HDMs) with Natural Flavour Conservation (NFC) in the channel $A^0\to h^0 Z$ (with $m_{h^0}=125$ GeV and $Z$ on-shell). In the absence of any signal, limits on the parameter space of $[\tan\beta, \cos(\beta-\alpha), m_{A^0}]$ in each 2HDM are derived for $m_{A^0} > 225$ GeV. In this work we consider the scenario of inverted hierarchy with $m_{h^0}<125$ GeV and $m_{H^0}=125$ GeV in which the decay $A^0\to h^0 Z^{(*)}$ (i.e. including the case of an off-shell $Z$) can have a large branching ratio in the 2HDM (Type I) for $m_{A^0}<225$ GeV. We calculate the signal cross section $\sigma(gg\to A^0)\times {\rm BR}(A^0\to h^0Z^{(*)})\times {\rm BR}(h^0\to b\overline b)$ in the 2HDM (Type I) with NFC and compare its magnitude with the cross section for the case of normal hierarchy ($m_{h^0}=125$ GeV) that is currently being searched for at the LHC. For the experimentally unexplored region $m_{A^0} < 225$ GeV it is shown that the above cross section for signal events in the scenario of inverted hierarchy can be of the order of a few picobarns. Such sizeable cross sections are several orders of magnitude larger than the cross sections for the case of normal hierarchy, thus motivating an extension of the ongoing searches for $A^0\to h^0 Z^{(*)}$ to probe the scenario of inverted hierarchy.
[ { "created": "Mon, 2 Jan 2023 15:44:51 GMT", "version": "v1" } ]
2023-08-09
[ [ "Akeroyd", "A. G.", "" ], [ "Alanazi", "S.", "" ], [ "Moretti", "Stefano", "" ] ]
Searches are being carried out at the Large Hadron Collider (LHC) for the decay of the CP-odd scalar ($A^0$) in Two-Higgs-Doublet Models (2HDMs) with Natural Flavour Conservation (NFC) in the channel $A^0\to h^0 Z$ (with $m_{h^0}=125$ GeV and $Z$ on-shell). In the absence of any signal, limits on the parameter space of $[\tan\beta, \cos(\beta-\alpha), m_{A^0}]$ in each 2HDM are derived for $m_{A^0} > 225$ GeV. In this work we consider the scenario of inverted hierarchy with $m_{h^0}<125$ GeV and $m_{H^0}=125$ GeV in which the decay $A^0\to h^0 Z^{(*)}$ (i.e. including the case of an off-shell $Z$) can have a large branching ratio in the 2HDM (Type I) for $m_{A^0}<225$ GeV. We calculate the signal cross section $\sigma(gg\to A^0)\times {\rm BR}(A^0\to h^0Z^{(*)})\times {\rm BR}(h^0\to b\overline b)$ in the 2HDM (Type I) with NFC and compare its magnitude with the cross section for the case of normal hierarchy ($m_{h^0}=125$ GeV) that is currently being searched for at the LHC. For the experimentally unexplored region $m_{A^0} < 225$ GeV it is shown that the above cross section for signal events in the scenario of inverted hierarchy can be of the order of a few picobarns. Such sizeable cross sections are several orders of magnitude larger than the cross sections for the case of normal hierarchy, thus motivating an extension of the ongoing searches for $A^0\to h^0 Z^{(*)}$ to probe the scenario of inverted hierarchy.
0908.4466
Aiichi Iwazaki
Aiichi Iwazaki
Pair Creation in Electric Flux Tube and Chiral Anomaly
7 pages, 4 figures
Phys.Rev.C80:052202,2009
10.1103/PhysRevC.80.052202
Nisho-3-2009
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Using chiral anomaly, we discuss the pair creation of massless fermions under the effect of magnetic field $\vec{B}$ when an electric flux tube $\vec{E}$ parallel to $\vec{B}$ is switched on. The tube is axial symmetric and infinitely long. In the limit $B\gg E$, we can analytically obtain the spatial and temporal behaviors of the number density of the fermions, the azimuthal magnetic field generated by the fermions etc.. We find that the life time $t_c$ of the electric field is shorter as the width of the tube is narrower. Applying it to the glasma in high-energy heavy-ion collisions, we find that color electric field decays fast such as $t_c\simeq Q_s^{-1}$ with saturation momentum $Q_s$.
[ { "created": "Mon, 31 Aug 2009 06:45:48 GMT", "version": "v1" } ]
2009-12-14
[ [ "Iwazaki", "Aiichi", "" ] ]
Using chiral anomaly, we discuss the pair creation of massless fermions under the effect of magnetic field $\vec{B}$ when an electric flux tube $\vec{E}$ parallel to $\vec{B}$ is switched on. The tube is axial symmetric and infinitely long. In the limit $B\gg E$, we can analytically obtain the spatial and temporal behaviors of the number density of the fermions, the azimuthal magnetic field generated by the fermions etc.. We find that the life time $t_c$ of the electric field is shorter as the width of the tube is narrower. Applying it to the glasma in high-energy heavy-ion collisions, we find that color electric field decays fast such as $t_c\simeq Q_s^{-1}$ with saturation momentum $Q_s$.
hep-ph/0501021
Richard F. Lebed
Richard F. Lebed
Baryon Resonances in the 1/N_c Expansion
12 pages, 4 eps figures, includes style files. Invited talk at ECT* Workshop on Large N_c QCD 2004, 5-9 July 2004, Trento, Italy
null
10.1142/9789812701725_0016
null
hep-ph
null
The 1/N_c expansion of QCD provides a valuable semiquantitative tool to study baryon scattering amplitudes and the short-lived baryon resonances embedded within them. A generalization of methods originally applied in chiral soliton models in the 1980's provides the key to deriving a rigorous 1/N_c expansion. One obtains model-independent relations among amplitudes that impose mass and width degeneracies among resonances of various quantum numbers. Phenomenological evidence confirms that patterns of resonant decay predicted by 1/N_c agree with data. One may extend the analysis to subleading orders in 1/N_c, where again agreement with data is evident, in both meson-baryon scattering and pion photoproduction.
[ { "created": "Tue, 4 Jan 2005 20:18:41 GMT", "version": "v1" } ]
2017-08-23
[ [ "Lebed", "Richard F.", "" ] ]
The 1/N_c expansion of QCD provides a valuable semiquantitative tool to study baryon scattering amplitudes and the short-lived baryon resonances embedded within them. A generalization of methods originally applied in chiral soliton models in the 1980's provides the key to deriving a rigorous 1/N_c expansion. One obtains model-independent relations among amplitudes that impose mass and width degeneracies among resonances of various quantum numbers. Phenomenological evidence confirms that patterns of resonant decay predicted by 1/N_c agree with data. One may extend the analysis to subleading orders in 1/N_c, where again agreement with data is evident, in both meson-baryon scattering and pion photoproduction.
hep-ph/9505368
Ed Yao
Paul Federbush (University of Michigan)
A New Formulation and Regularization of Gauge Theories Using a Non-Linear Wavelet Expansion
22 pages lateX. A better form of determinants is given in chapters 4 and 5
Prog.Theor.Phys. 94 (1995) 1135-1146
10.1143/PTP.94.1135
null
hep-ph hep-th
null
The Euclidean version of the Yang-Mills theory is studied in four dimensions. The field is expressed non-linearly in terms of the basic variables. The field is developed inductively, adding one excitation at a time. A given excitation is added into the ``background field'' of the excitations already added, the background field expressed in a radially axial gauge about the point where the excitation is centered. The linearization of the resultant expression for the field is an expansion $$ A_\mu(x) \ \cong \ \sum_\alpha \; c_\alpha \; \psi_\mu^\alpha(x) $$ where $\psi^\alpha_\mu(x)$ is a divergence-free wavelet and $c_\alpha$ is the associated basic variable, a Lie Algebra element of the gauge group. One is working in a particular gauge, regularization is simply cutoff regularization realized by omitting wavelet excitations below a certain length scale. We will prove in a later paper that only the usual gauge-invariant counterterms are required to renormalize perturbation theory. Using related ideas, but essentially independent of the rest of paper, we find an expression for the determinant of a gauged boson or fermion field in a fixed ``small'' external gauge field. This determinant is expressed in terms of explicitly gauge invariant quantities, and again may be regularized by a cutoff regularization. We leave to later work relating these regularizations to the usual dimensional regularization.
[ { "created": "Tue, 23 May 1995 17:46:53 GMT", "version": "v1" }, { "created": "Thu, 8 Jun 1995 13:09:50 GMT", "version": "v2" } ]
2016-09-01
[ [ "Federbush", "Paul", "", "University of Michigan" ] ]
The Euclidean version of the Yang-Mills theory is studied in four dimensions. The field is expressed non-linearly in terms of the basic variables. The field is developed inductively, adding one excitation at a time. A given excitation is added into the ``background field'' of the excitations already added, the background field expressed in a radially axial gauge about the point where the excitation is centered. The linearization of the resultant expression for the field is an expansion $$ A_\mu(x) \ \cong \ \sum_\alpha \; c_\alpha \; \psi_\mu^\alpha(x) $$ where $\psi^\alpha_\mu(x)$ is a divergence-free wavelet and $c_\alpha$ is the associated basic variable, a Lie Algebra element of the gauge group. One is working in a particular gauge, regularization is simply cutoff regularization realized by omitting wavelet excitations below a certain length scale. We will prove in a later paper that only the usual gauge-invariant counterterms are required to renormalize perturbation theory. Using related ideas, but essentially independent of the rest of paper, we find an expression for the determinant of a gauged boson or fermion field in a fixed ``small'' external gauge field. This determinant is expressed in terms of explicitly gauge invariant quantities, and again may be regularized by a cutoff regularization. We leave to later work relating these regularizations to the usual dimensional regularization.
2212.03424
Boris Kopeliovich
B. Z. Kopeliovich, I. K. Potashnikova, Ivan Schmidt
The Low theorem for diffractive bremsstrahlung and the soft photon puzzle
Presented at "Diffraction and Low-x 2022'', Corigliano Calabro (Italy), September 24-30, 2022
null
null
null
hep-ph hep-ex
http://creativecommons.org/licenses/by/4.0/
The anomalous excess of small-kT photons radiated along with multi-hadron production, is challenging the physics community over four decades, but no solution has been proposed so far. We argue that the problem is rooted in the comparison with an incorrect model, usually called bremsstrahlung model. It is believed to be an extension of the Low theorem from the 2 -> 2+gamma process to radiative multi-particle production 2 -> n+gamma, where either initial, or final charged hadrons participate in radiation. We demonstrate that this breaks down unitarity of the S-matrix, so contradicts the optical theorem.
[ { "created": "Wed, 7 Dec 2022 03:16:09 GMT", "version": "v1" }, { "created": "Sun, 18 Dec 2022 20:06:25 GMT", "version": "v2" } ]
2022-12-20
[ [ "Kopeliovich", "B. Z.", "" ], [ "Potashnikova", "I. K.", "" ], [ "Schmidt", "Ivan", "" ] ]
The anomalous excess of small-kT photons radiated along with multi-hadron production, is challenging the physics community over four decades, but no solution has been proposed so far. We argue that the problem is rooted in the comparison with an incorrect model, usually called bremsstrahlung model. It is believed to be an extension of the Low theorem from the 2 -> 2+gamma process to radiative multi-particle production 2 -> n+gamma, where either initial, or final charged hadrons participate in radiation. We demonstrate that this breaks down unitarity of the S-matrix, so contradicts the optical theorem.
2403.04644
Kevin Hinze
Kevin Hinze and Shaikh Saad
Leptoquark-Mediated Two-Loop Neutrino Mass in Unified Theory
Discussion on proton decay has been expanded. Accepted in PLB (to appear)
null
null
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
Scalar leptoquarks naturally arise within unified theories, offering a promising avenue for addressing one of the most significant challenges of the Standard Model--the existence of non-zero neutrino masses. In this work, we present a unified theory based on the SU(5) gauge group, where neutrino mass appears at the two-loop level via the propagation of scalar leptoquarks. Due to the unified framework, the charged fermion and neutrino masses and mixings are entangled and determined by a common set of Yukawa couplings. These exotic particles not only shed light on the neutrino mass generation mechanism but also help to achieve the unification of gauge couplings and are expected to lead to substantial lepton flavor violating rates, offering tangible opportunities for experimental verification. Reproducing the observed neutrino mass scale necessitates that a set of leptoquarks reside a few orders of magnitude below the unification scale--a specific feature of the proposed scenario. Moreover, maximizing the unification scale implies TeV scale new physics states, making them accessible at colliders. The diverse roles that leptoquarks play highlight the elegance and predictive ability of the proposed unified model.
[ { "created": "Thu, 7 Mar 2024 16:43:15 GMT", "version": "v1" }, { "created": "Tue, 21 May 2024 12:27:58 GMT", "version": "v2" } ]
2024-05-22
[ [ "Hinze", "Kevin", "" ], [ "Saad", "Shaikh", "" ] ]
Scalar leptoquarks naturally arise within unified theories, offering a promising avenue for addressing one of the most significant challenges of the Standard Model--the existence of non-zero neutrino masses. In this work, we present a unified theory based on the SU(5) gauge group, where neutrino mass appears at the two-loop level via the propagation of scalar leptoquarks. Due to the unified framework, the charged fermion and neutrino masses and mixings are entangled and determined by a common set of Yukawa couplings. These exotic particles not only shed light on the neutrino mass generation mechanism but also help to achieve the unification of gauge couplings and are expected to lead to substantial lepton flavor violating rates, offering tangible opportunities for experimental verification. Reproducing the observed neutrino mass scale necessitates that a set of leptoquarks reside a few orders of magnitude below the unification scale--a specific feature of the proposed scenario. Moreover, maximizing the unification scale implies TeV scale new physics states, making them accessible at colliders. The diverse roles that leptoquarks play highlight the elegance and predictive ability of the proposed unified model.
2308.12356
Miguel Echevarria
Miguel G. Echevarria, Samuel F. Romera and Ignazio Scimemi
Gluon TMD fragmentation function into quarkonium
v3: matches published version; v2: typos corrected; v1: 29 pages, 2 figures
null
10.1007/JHEP12(2023)181
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
We compute the gluon transverse-momentum-dependent fragmentation function (TMDFF) at next-to-leading order (NLO) into heavy quarkonium in the color-octet $^3S_1^{[8]}$ channel, based on the NRQCD factorization approach. The spurious rapidity divergences are explicitly shown to cancel in a well-defined TMDFF, which incorporates the needed soft factor. We also compute the integrated gluon FF at NLO in the same $^3S_1^{[8]}$ channel, and show that the matching coefficient of the TMDFF onto the FF at large transverse momentum is the expected one. These results are relevant to perform precise and sensible phenomenological studies of transverse-momentum spectra of quarkonium production, for which the production mechanism through fragmentation plays a relevant role, like in the future Electron-Ion Collider.
[ { "created": "Wed, 23 Aug 2023 18:03:01 GMT", "version": "v1" }, { "created": "Thu, 31 Aug 2023 07:54:49 GMT", "version": "v2" }, { "created": "Mon, 1 Jan 2024 08:18:02 GMT", "version": "v3" } ]
2024-01-02
[ [ "Echevarria", "Miguel G.", "" ], [ "Romera", "Samuel F.", "" ], [ "Scimemi", "Ignazio", "" ] ]
We compute the gluon transverse-momentum-dependent fragmentation function (TMDFF) at next-to-leading order (NLO) into heavy quarkonium in the color-octet $^3S_1^{[8]}$ channel, based on the NRQCD factorization approach. The spurious rapidity divergences are explicitly shown to cancel in a well-defined TMDFF, which incorporates the needed soft factor. We also compute the integrated gluon FF at NLO in the same $^3S_1^{[8]}$ channel, and show that the matching coefficient of the TMDFF onto the FF at large transverse momentum is the expected one. These results are relevant to perform precise and sensible phenomenological studies of transverse-momentum spectra of quarkonium production, for which the production mechanism through fragmentation plays a relevant role, like in the future Electron-Ion Collider.
hep-ph/0206051
Wolfram Weise
Wolfram Weise
Baryons 2002: Outlook
10 pages, to be publ.in: Proceedings Int. Conf. BARYONS 2002, Jefferson Lab., March 2002
null
10.1142/9789812704887_0025
Preprint ECT*-02-10
hep-ph
null
Summary and outlook presented at the 9th International Conference on the Structure of Baryons (BARYONS 2002), Jefferson Lab, March 3-8, 2002
[ { "created": "Wed, 5 Jun 2002 13:24:27 GMT", "version": "v1" } ]
2017-08-23
[ [ "Weise", "Wolfram", "" ] ]
Summary and outlook presented at the 9th International Conference on the Structure of Baryons (BARYONS 2002), Jefferson Lab, March 3-8, 2002
1509.01242
Konrad Tywoniuk
Wojciech Florkowski, Radoslaw Ryblewski, Nan Su, Konrad Tywoniuk
Transport coefficients of the Gribov-Zwanziger plasma
21 pages, 11 figures, minor changes: results obtained with momentum-dependent relaxation time are corrected, conclusions unmodified
Phys. Rev. C 94, 044904 (2016)
10.1103/PhysRevC.94.044904
null
hep-ph hep-th nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study dynamic features of a plasma consisting of gluons whose infrared dynamics is improved by the Gribov-Zwanziger quantization. This approach embodies essential features of color confinement which set the plasma apart from conventional quasiparticle systems in several aspects. Our study focusses on a boost-invariant expansion for in- and out-of-equilibrium settings, which at late times can be characterized by the sound velocity, $c_s$, and the shear, $\eta$, and bulk, $\zeta$, viscosities. We obtain explicit expressions for the transport coefficients $\eta$ and $\zeta$ and check that they are consistent with the numerical solutions of the kinetic equation. At high temperature, keeping both the Gribov parameter and the relaxation time constant, we find a scaling $\zeta/\eta \propto 1/3 - c_s^2$ which manifests strong breaking of conformal symmetry in contrast to the case of weakly coupled plasmas.
[ { "created": "Thu, 3 Sep 2015 19:56:43 GMT", "version": "v1" }, { "created": "Sun, 21 Feb 2016 19:52:55 GMT", "version": "v2" }, { "created": "Fri, 20 May 2016 08:36:31 GMT", "version": "v3" } ]
2016-10-19
[ [ "Florkowski", "Wojciech", "" ], [ "Ryblewski", "Radoslaw", "" ], [ "Su", "Nan", "" ], [ "Tywoniuk", "Konrad", "" ] ]
We study dynamic features of a plasma consisting of gluons whose infrared dynamics is improved by the Gribov-Zwanziger quantization. This approach embodies essential features of color confinement which set the plasma apart from conventional quasiparticle systems in several aspects. Our study focusses on a boost-invariant expansion for in- and out-of-equilibrium settings, which at late times can be characterized by the sound velocity, $c_s$, and the shear, $\eta$, and bulk, $\zeta$, viscosities. We obtain explicit expressions for the transport coefficients $\eta$ and $\zeta$ and check that they are consistent with the numerical solutions of the kinetic equation. At high temperature, keeping both the Gribov parameter and the relaxation time constant, we find a scaling $\zeta/\eta \propto 1/3 - c_s^2$ which manifests strong breaking of conformal symmetry in contrast to the case of weakly coupled plasmas.
hep-ph/0511175
Ivan Schmidt
Ivan Schmidt
Quark and Gluon Sivers Functions
8 Pages. Talk given at The International Workshop on Transverse Polarisation Phenomena in Hard Processes (Transversity 2005), Como, Italy, 7&#8722;10 September 2005
null
10.1142/9789812773272_0024
USM-TH-172
hep-ph
null
The physics of hadron single transverse spin asymmetries is discussed. Possible measurements of both the quark and gluon Sivers functions are proposed.
[ { "created": "Mon, 14 Nov 2005 19:15:53 GMT", "version": "v1" } ]
2017-08-23
[ [ "Schmidt", "Ivan", "" ] ]
The physics of hadron single transverse spin asymmetries is discussed. Possible measurements of both the quark and gluon Sivers functions are proposed.
2403.13494
Phung Van Dong
Doan Minh Luong, Phung Van Dong, Nguyen Huy Thao
Novel imprint of a dark photon from the 3-3-1-1 model
16 pages, 3 figures, 2 tables; A scalar triplet relabelled for clarity
null
null
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
We investigate a dark photon that arises from the UV model based upon $SU(3)_C\otimes SU(3)_L\otimes U(1)_X \otimes U(1)_G$ (3-3-1-1) gauge symmetry, where the last three factors enlarge the electroweak symmetry encompassing electric charge $Q=T_3 - 1/ \sqrt{3}T_8 +X$ and dark charge $D = -2/\sqrt{3} T_8 +G$. It is well-established that this model addresses the questions of family number, neutrino mass, and dark matter. It is shown in this work that if the 3-3-1-1 breaking scale is much bigger than the dark charge breaking scale, the relevant dark gauge boson $Z'$ is uniquely imprinted at TeV, avoiding dangerous FCNC processes, obeying precision electroweak measurements, as well as contributing to collider phenomena, even if no kinetic mixing is presented. The dark matter observables are perhaps governed by the dark charge breaking Higgs field instead of the dark photon.
[ { "created": "Wed, 20 Mar 2024 10:51:38 GMT", "version": "v1" }, { "created": "Sat, 23 Mar 2024 10:05:56 GMT", "version": "v2" } ]
2024-03-26
[ [ "Luong", "Doan Minh", "" ], [ "Van Dong", "Phung", "" ], [ "Thao", "Nguyen Huy", "" ] ]
We investigate a dark photon that arises from the UV model based upon $SU(3)_C\otimes SU(3)_L\otimes U(1)_X \otimes U(1)_G$ (3-3-1-1) gauge symmetry, where the last three factors enlarge the electroweak symmetry encompassing electric charge $Q=T_3 - 1/ \sqrt{3}T_8 +X$ and dark charge $D = -2/\sqrt{3} T_8 +G$. It is well-established that this model addresses the questions of family number, neutrino mass, and dark matter. It is shown in this work that if the 3-3-1-1 breaking scale is much bigger than the dark charge breaking scale, the relevant dark gauge boson $Z'$ is uniquely imprinted at TeV, avoiding dangerous FCNC processes, obeying precision electroweak measurements, as well as contributing to collider phenomena, even if no kinetic mixing is presented. The dark matter observables are perhaps governed by the dark charge breaking Higgs field instead of the dark photon.
hep-ph/9503452
Giovanni Amelino-Camelia
G. Amelino-Camelia (MIT), O. Pisanti (Univ. Napoli), L. Rosa (Univ. Napoli)
SO(10): a possible Scenario for new Physics in the Neutrino Sector and Baryogenesis
4 pages, LaTex (requires espcrc2.sty which is appended). Contribution to the Proceedings of Trends in Astroparticle Physics
Nucl.Phys.Proc.Suppl. 43 (1995) 86-89
10.1016/0920-5632(95)00458-L
MIT-CTP-2420
hep-ph
null
The implications on neutrino physics and on the dynamical generation of the baryonic asymmetry of a class of $SO(10)$ non-supersymmetric models are discussed.
[ { "created": "Mon, 27 Mar 1995 22:23:28 GMT", "version": "v1" } ]
2009-10-28
[ [ "Amelino-Camelia", "G.", "", "MIT" ], [ "Pisanti", "O.", "", "Univ. Napoli" ], [ "Rosa", "L.", "", "Univ.\n Napoli" ] ]
The implications on neutrino physics and on the dynamical generation of the baryonic asymmetry of a class of $SO(10)$ non-supersymmetric models are discussed.
2305.04943
David Morrissey
Andrea Gaspert, Pietro Giampa, Navin McGinnis, David E. Morrissey
Dark Matter Direct Detection on the Moon
7+4 pages, 3+3 figures, includes supplemental material
null
null
null
hep-ph hep-ex
http://creativecommons.org/licenses/by/4.0/
Direct searches for dark matter with large-scale noble liquid detectors have become sensitive enough to detect the coherent scattering of local neutrinos. This will become a very challenging background to dark matter discovery in planned future detectors. For dark matter with mass above 10 GeV, the dominant neutrino backgrounds on the Earth are atmospheric neutrinos created by cosmic ray collisions with the atmosphere. In contrast, the Moon has almost no atmosphere and nearly all cosmic rays incident on the Moon first collide with the lunar surface, producing a very different neutrino spectrum. In this work we estimate the total flux and spectrum of neutrinos near the surface of the Moon. We then use this to show that a large-scale liquid xenon or argon detector located on the Moon could potentially have significantly greater sensitivity to dark matter compared to an equivalent detector on the Earth due to effectively reduced neutrino backgrounds.
[ { "created": "Mon, 8 May 2023 18:00:00 GMT", "version": "v1" } ]
2023-05-10
[ [ "Gaspert", "Andrea", "" ], [ "Giampa", "Pietro", "" ], [ "McGinnis", "Navin", "" ], [ "Morrissey", "David E.", "" ] ]
Direct searches for dark matter with large-scale noble liquid detectors have become sensitive enough to detect the coherent scattering of local neutrinos. This will become a very challenging background to dark matter discovery in planned future detectors. For dark matter with mass above 10 GeV, the dominant neutrino backgrounds on the Earth are atmospheric neutrinos created by cosmic ray collisions with the atmosphere. In contrast, the Moon has almost no atmosphere and nearly all cosmic rays incident on the Moon first collide with the lunar surface, producing a very different neutrino spectrum. In this work we estimate the total flux and spectrum of neutrinos near the surface of the Moon. We then use this to show that a large-scale liquid xenon or argon detector located on the Moon could potentially have significantly greater sensitivity to dark matter compared to an equivalent detector on the Earth due to effectively reduced neutrino backgrounds.
hep-ph/0703255
Richard Williams M.Sci
R. Williams, C. S. Fischer, M. R. Pennington
Quark Condensates: Flavour Dependence
9 pages, 7 figures, uses appolb.cls, LaTeX. Talk presented by R. Williams at the EURIDICE Final Meeting, August 24-27th, 2006, Kazimierz, Poland
ActaPhys.Polon.B38:2803-2810,2007
null
null
hep-ph
null
We determine the q-bar q condensate for quark masses from zero up to that of the strange quark within a phenomenologically successful modelling of continuum QCD by solving the quark Schwinger-Dyson equation. The existence of multiple solutions to this equation is the key to an accurate and reliable extraction of this condensate using the operator product expansion. We explain why alternative definitions fail to give the physical condensate.
[ { "created": "Fri, 23 Mar 2007 16:19:28 GMT", "version": "v1" } ]
2008-11-26
[ [ "Williams", "R.", "" ], [ "Fischer", "C. S.", "" ], [ "Pennington", "M. R.", "" ] ]
We determine the q-bar q condensate for quark masses from zero up to that of the strange quark within a phenomenologically successful modelling of continuum QCD by solving the quark Schwinger-Dyson equation. The existence of multiple solutions to this equation is the key to an accurate and reliable extraction of this condensate using the operator product expansion. We explain why alternative definitions fail to give the physical condensate.
1302.1101
C\'eline Degrande
Celine Degrande
New physics in top decay
5 pages, 3 figures, Proceedings for Top2012
null
10.1088/1742-6596/452/1/012009
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
After a short introduction to effective field theories, most of their features are illustrated using the top decay. The effects of heavy new physics on the top decay are computed and the constraints on the coefficients of the dimension-six operators are derived from the available measurements.
[ { "created": "Tue, 5 Feb 2013 16:35:18 GMT", "version": "v1" } ]
2015-06-12
[ [ "Degrande", "Celine", "" ] ]
After a short introduction to effective field theories, most of their features are illustrated using the top decay. The effects of heavy new physics on the top decay are computed and the constraints on the coefficients of the dimension-six operators are derived from the available measurements.
hep-ph/9406248
My Account
T. Kamon, J. Lopez, P. McIntyre, and J. White
Supersymmetry at the DiTevatron
38 pages, Latex, 12 figures (not included). Figures are available via anonymous ftp from hplaa02.cern.ch (/pub/lopez) as one uuencoded file (DiTevFigs.uu, 0.731MB). CTP-TAMU-19/94
Phys.Rev.D50:5676-5691,1994
10.1103/PhysRevD.50.5676
null
hep-ph hep-ex
null
We study the signals for supersymmetry at the Tevatron and DiTevatron ($\sqrt{s}=4\TeV$) in various well-motivated supersymmetric models. We consider the trilepton signature in the decay of pair-produced charginos and neutralinos, the missing energy signature in gluino and squark production, and the $b\bar b$ signal in the decay of the lightest supersymmetric Higgs boson produced in association with a $W$ or $Z$ boson. In each case we perform signal and background studies, using Monte Carlo and/or real data to estimate the sensitivity to these signals at the Tevatron and DiTevatron with the Main Injector, for short- and long-term integrated luminosities of ${\cal L}=10$ and $25\ifb$, and $5\sigma$ statistical significance. We conclude that one could probe chargino masses as high as $m_{\chi^\pm_1}\sim180\,(200)\GeV$, gluino masses as high as $m_{\tilde g}\sim450\,(750)\GeV$, and lightest Higgs boson masses as high as $m_h\sim110\,(120)\GeV$ at the Tevatron (DiTevatron). A high-luminosity option at the Tevatron ($10^{33}\cm^{-2}\s^{-1}$) may compensate somewhat for the higher reach of the DiTevatron, but only in the trilepton and Higgs signals. However, these gains may be severely compromised once the multiple-interaction environment of the high-luminosity Tevatron is accounted for.
[ { "created": "Tue, 7 Jun 1994 22:11:05 GMT", "version": "v1" } ]
2011-08-17
[ [ "Kamon", "T.", "" ], [ "Lopez", "J.", "" ], [ "McIntyre", "P.", "" ], [ "White", "J.", "" ] ]
We study the signals for supersymmetry at the Tevatron and DiTevatron ($\sqrt{s}=4\TeV$) in various well-motivated supersymmetric models. We consider the trilepton signature in the decay of pair-produced charginos and neutralinos, the missing energy signature in gluino and squark production, and the $b\bar b$ signal in the decay of the lightest supersymmetric Higgs boson produced in association with a $W$ or $Z$ boson. In each case we perform signal and background studies, using Monte Carlo and/or real data to estimate the sensitivity to these signals at the Tevatron and DiTevatron with the Main Injector, for short- and long-term integrated luminosities of ${\cal L}=10$ and $25\ifb$, and $5\sigma$ statistical significance. We conclude that one could probe chargino masses as high as $m_{\chi^\pm_1}\sim180\,(200)\GeV$, gluino masses as high as $m_{\tilde g}\sim450\,(750)\GeV$, and lightest Higgs boson masses as high as $m_h\sim110\,(120)\GeV$ at the Tevatron (DiTevatron). A high-luminosity option at the Tevatron ($10^{33}\cm^{-2}\s^{-1}$) may compensate somewhat for the higher reach of the DiTevatron, but only in the trilepton and Higgs signals. However, these gains may be severely compromised once the multiple-interaction environment of the high-luminosity Tevatron is accounted for.
2107.08812
Oscar Garcia-Montero
Oscar Garcia-Montero, Jan Staudenmaier, Anna Sch\"afer, Juan M. Torres-Rincon and Hannah Elfner
The role of proton-antiproton regeneration in the late stages of heavy-ion collisions
6 pages, 4 figures
null
10.1103/PhysRevC.105.064906
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate the long-standing question of the effect of proton-antiproton annihilation on the (anti-)proton yield, while respecting detailed balance for the 5-body back-reaction for the first time in a full microscopic description of the late stages of heavy-ion collisions. This is achieved by employing a stochastic collision criterion in a hadronic transport approach (SMASH), which allows to treat arbitrary multi-particle reactions. It is used to account for the regeneration of (anti-)protons via $5\pi\rightarrow p\bar{p}$. Our results show that a back-reaction happens for a fraction of 15-20\% of all annihilations. Within a viscous hybrid approach Au+Au/Pb+Pb collisions from $\sqrt{s_{NN}}=17.3$ GeV$-5.02$ TeV are investigated and the quoted fraction is independent of the beam energy or centrality of the collision. Taking the back-reaction into account results in regeneration of half of the (anti-)proton yield that is lost due to annihilations at midrapidity. We also find that, concerning the multiplicities, treating the back-reaction as a chain of 2-body reactions is equivalent to a single 5-to-2 reaction.
[ { "created": "Mon, 19 Jul 2021 12:47:40 GMT", "version": "v1" } ]
2022-06-22
[ [ "Garcia-Montero", "Oscar", "" ], [ "Staudenmaier", "Jan", "" ], [ "Schäfer", "Anna", "" ], [ "Torres-Rincon", "Juan M.", "" ], [ "Elfner", "Hannah", "" ] ]
We investigate the long-standing question of the effect of proton-antiproton annihilation on the (anti-)proton yield, while respecting detailed balance for the 5-body back-reaction for the first time in a full microscopic description of the late stages of heavy-ion collisions. This is achieved by employing a stochastic collision criterion in a hadronic transport approach (SMASH), which allows to treat arbitrary multi-particle reactions. It is used to account for the regeneration of (anti-)protons via $5\pi\rightarrow p\bar{p}$. Our results show that a back-reaction happens for a fraction of 15-20\% of all annihilations. Within a viscous hybrid approach Au+Au/Pb+Pb collisions from $\sqrt{s_{NN}}=17.3$ GeV$-5.02$ TeV are investigated and the quoted fraction is independent of the beam energy or centrality of the collision. Taking the back-reaction into account results in regeneration of half of the (anti-)proton yield that is lost due to annihilations at midrapidity. We also find that, concerning the multiplicities, treating the back-reaction as a chain of 2-body reactions is equivalent to a single 5-to-2 reaction.
hep-ph/0210346
Dmitry Anchishkin
D. Anchishkin, V. Khryapa and V. Ruuskanen
Thermal Dilepton Radiation from Finite Fireball
17 pages, revtex, 9 figures
null
null
ITP-02-15E
hep-ph
null
We analyze the dilepton emission rates from the hot pion gas confined to a finite space-time volume. Two models of pion(+) pion(-) annihilation to dileptons are under consideration. The first model mimics an extreme influence of the dense hadron environment on the rho-meson mean free path and mean life time. The second model deals with the standard concept of vector meson dominance when the hadron medium is not accounted. Our results indicate that the dilepton rates are finite in the low invariant mass region M<2m_\pi. It is found that the rates experience an enhancement in the electron-positron production when invariant mass tends to the "real" threshold M=2m_e. The breaking of the detailled energy-momentum conservation in favour of the integral one due to broken translation invariance is discussed.
[ { "created": "Fri, 25 Oct 2002 09:34:50 GMT", "version": "v1" } ]
2007-05-23
[ [ "Anchishkin", "D.", "" ], [ "Khryapa", "V.", "" ], [ "Ruuskanen", "V.", "" ] ]
We analyze the dilepton emission rates from the hot pion gas confined to a finite space-time volume. Two models of pion(+) pion(-) annihilation to dileptons are under consideration. The first model mimics an extreme influence of the dense hadron environment on the rho-meson mean free path and mean life time. The second model deals with the standard concept of vector meson dominance when the hadron medium is not accounted. Our results indicate that the dilepton rates are finite in the low invariant mass region M<2m_\pi. It is found that the rates experience an enhancement in the electron-positron production when invariant mass tends to the "real" threshold M=2m_e. The breaking of the detailled energy-momentum conservation in favour of the integral one due to broken translation invariance is discussed.
hep-ph/0111180
Steven D. Bass
Steven D. Bass
Gluonic effects in eta and eta-prime physics
20 pages, 2 figures, Invited talk at the WASA Workshop on Eta Physics, October 2001, Uppsala, Sweden
Phys.Scripta T99 (2002) 96-103
10.1238/Physica.Topical.099a00096
ECT-01-030
hep-ph
null
We review the theory and phenomenology of the axial U(1) problem with emphasis on the role of gluonic degrees of freedom in eta and eta' production processes, especially the low-energy pN -> pN eta and pN -> pN eta' reactions.
[ { "created": "Wed, 14 Nov 2001 20:03:00 GMT", "version": "v1" } ]
2009-11-07
[ [ "Bass", "Steven D.", "" ] ]
We review the theory and phenomenology of the axial U(1) problem with emphasis on the role of gluonic degrees of freedom in eta and eta' production processes, especially the low-energy pN -> pN eta and pN -> pN eta' reactions.
1611.03240
Weijian Wang
Weijian Wang and Zhi-Long Han
Naturally Small Dirac Neutrino Mass with Intermediate $SU(2)_{L}$ Multiplet Fields
31 pages, 16 figures
JHEP04 (2017) 166
10.1007/JHEP04(2017)166
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
If neutrinos are Dirac fermions, certain new physics beyond the standard model should exist to account for the smallness of neutrino mass. With two additional scalars and a heavy intermediate fermion, in this paper, we systematically study the general mechanism that can natrally generate the tiny Dirac neutrino mass at tree and in one-loop level. For tree level models, we focus on natural ones, in which the additional scalars develop small vacuum expectation values without fine-tuning. For one-loop level models, we explore those having dark matter candidates under $Z_2^D$ symmetry. In both cases, we concentrate on $SU(2)_L$ multiplet scalars no larger than quintuplet, and derive the complete sets of viable models. Phenomenologies, such as lepton flavor violation, leptogenesis, and LHC signatures are briefly discussed.
[ { "created": "Thu, 10 Nov 2016 09:59:52 GMT", "version": "v1" }, { "created": "Mon, 14 Nov 2016 10:01:39 GMT", "version": "v2" }, { "created": "Thu, 16 Feb 2017 14:10:49 GMT", "version": "v3" }, { "created": "Mon, 1 May 2017 03:31:10 GMT", "version": "v4" } ]
2017-05-02
[ [ "Wang", "Weijian", "" ], [ "Han", "Zhi-Long", "" ] ]
If neutrinos are Dirac fermions, certain new physics beyond the standard model should exist to account for the smallness of neutrino mass. With two additional scalars and a heavy intermediate fermion, in this paper, we systematically study the general mechanism that can natrally generate the tiny Dirac neutrino mass at tree and in one-loop level. For tree level models, we focus on natural ones, in which the additional scalars develop small vacuum expectation values without fine-tuning. For one-loop level models, we explore those having dark matter candidates under $Z_2^D$ symmetry. In both cases, we concentrate on $SU(2)_L$ multiplet scalars no larger than quintuplet, and derive the complete sets of viable models. Phenomenologies, such as lepton flavor violation, leptogenesis, and LHC signatures are briefly discussed.
hep-ph/9607335
Emilio Torrente
Emilio Torrente-Lujan
Fermion Scattering in domain walls with a locally dependent phase
14 pages, 3 eps figures (epsfig macro neccesary). uuencoded. also avalaible at http://www-itp.unibe.ch/~torrente
null
null
butp-9612
hep-ph
null
We consider interactions of fermions with the domain wall bubbles produced during a first order phase transition. A new exact solution of the Dirac equations is obtained for a wall profile incorporating a position dependent phase factor. The reflection coefficients are obtained.
[ { "created": "Tue, 16 Jul 1996 12:15:15 GMT", "version": "v1" } ]
2007-05-23
[ [ "Torrente-Lujan", "Emilio", "" ] ]
We consider interactions of fermions with the domain wall bubbles produced during a first order phase transition. A new exact solution of the Dirac equations is obtained for a wall profile incorporating a position dependent phase factor. The reflection coefficients are obtained.
hep-ph/0603155
Kari J. Eskola
K. J. Eskola and H. Paukkunen
NuTeV $\sin ^2 \theta_{\rm W}$ anomaly and nuclear parton distributions revisited
17 pages, 7 figures
JHEP0606:008,2006
10.1088/1126-6708/2006/06/008
HIP-2006-15/TH
hep-ph
null
By studying the Paschos-Wolfenstein (PW) ratio of deep inelastic $\nu{\rm Fe}$ and $\bar \nu{\rm Fe}$ scattering cross sections, we show that it should be possible to explain the NuTeV $\sin ^2 \theta_{\rm W}$ anomaly with quite conventional physics, by introducing mutually different nuclear modifications for the valence-$u$ and valence-$d$ quark distributions of the protons in iron. Keeping the EKS98 nuclear modifications for $u_V+d_V$ as a baseline, we find that some 20-30 % nuclear modifications to the $u_V$ and $d_V$ distributions account for the change induced in the PW ratio by the NuTeV-suggested increase $\Delta \sin ^2 \theta_{\rm W}=0.005$. We show that introduction of such nuclear modifications in $u_V$ and $d_V$ individually, does not lead into contradiction with the present global DGLAP analyses of the nuclear parton distributions, where deep inelastic $lA$ scattering data and Drell-Yan dilepton data from $pA$ collisions are used as constraints. We thus suggest that the NuTeV result serves as an important further constraint in pinning down the nuclear effects of the bound nucleon PDFs. We also predict that if the NuTeV anomaly is explained by this mechanism, the NOMAD experiment should see an increase in the weak mixing angle quite close to the NuTeV result.
[ { "created": "Tue, 21 Mar 2006 08:32:40 GMT", "version": "v1" } ]
2009-11-11
[ [ "Eskola", "K. J.", "" ], [ "Paukkunen", "H.", "" ] ]
By studying the Paschos-Wolfenstein (PW) ratio of deep inelastic $\nu{\rm Fe}$ and $\bar \nu{\rm Fe}$ scattering cross sections, we show that it should be possible to explain the NuTeV $\sin ^2 \theta_{\rm W}$ anomaly with quite conventional physics, by introducing mutually different nuclear modifications for the valence-$u$ and valence-$d$ quark distributions of the protons in iron. Keeping the EKS98 nuclear modifications for $u_V+d_V$ as a baseline, we find that some 20-30 % nuclear modifications to the $u_V$ and $d_V$ distributions account for the change induced in the PW ratio by the NuTeV-suggested increase $\Delta \sin ^2 \theta_{\rm W}=0.005$. We show that introduction of such nuclear modifications in $u_V$ and $d_V$ individually, does not lead into contradiction with the present global DGLAP analyses of the nuclear parton distributions, where deep inelastic $lA$ scattering data and Drell-Yan dilepton data from $pA$ collisions are used as constraints. We thus suggest that the NuTeV result serves as an important further constraint in pinning down the nuclear effects of the bound nucleon PDFs. We also predict that if the NuTeV anomaly is explained by this mechanism, the NOMAD experiment should see an increase in the weak mixing angle quite close to the NuTeV result.
hep-ph/9902352
Toby Falk
Toby Falk
Higgsinos in SUSY Models with Gaugino Mass Unification
10 pages in LaTeX with 4 encapsulated postscript figures; uses epsf.sty. Version to appear in Physics Letters B
Phys.Lett. B456 (1999) 171-178
10.1016/S0370-2693(99)00501-8
MADPH-99-1104
hep-ph
null
In the MSSM, the assumptions of a common sfermion mass parameter m_0 and a common gaugino mass parameter m_1/2, along with the requirements from radiative electroweak symmetry breaking, lead to relatively large values of the Higgs mixing parameter mu, and consequently to a gaugino-like lightest neutralino. Lifting the requirement that the Higgs mass parameters unify with the sfermion masses is known to allow for smaller mu. We show that a mu parameter sufficiently small to yield a Higgsino-like neutralino requires a precise adjustment of the Higgs mass parameter m_Hu. Consequently a gaugino-type neutralino is still preferred in SUSY models with gaugino mass unification.
[ { "created": "Tue, 16 Feb 1999 01:10:56 GMT", "version": "v1" }, { "created": "Tue, 20 Apr 1999 14:39:44 GMT", "version": "v2" } ]
2009-10-31
[ [ "Falk", "Toby", "" ] ]
In the MSSM, the assumptions of a common sfermion mass parameter m_0 and a common gaugino mass parameter m_1/2, along with the requirements from radiative electroweak symmetry breaking, lead to relatively large values of the Higgs mixing parameter mu, and consequently to a gaugino-like lightest neutralino. Lifting the requirement that the Higgs mass parameters unify with the sfermion masses is known to allow for smaller mu. We show that a mu parameter sufficiently small to yield a Higgsino-like neutralino requires a precise adjustment of the Higgs mass parameter m_Hu. Consequently a gaugino-type neutralino is still preferred in SUSY models with gaugino mass unification.
1912.09106
Cedric Mezrag
C\'edric Mezrag, Nabil Chouika, Herv\'e Moutarde and Jose Rodriguez-Quintero
Basic properties of GPDs and modelling of the latter
Contribution to the proceedings of Lightcone 2019, \'Ecole Polytechnique, Palaiseau, France
null
null
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present here a new method based on the Radon transform to model Generalised Parton Distributions (GPDs). It allows to fulfil all theoretical constraints applying on GPDs, especially polynomiality and positivity at the same time. More specifically, we show how polynomiality can be systematically restored within the framework of the overlaps of Lightfront Wave Functions (LFWFs). It provides a systematic way to extend models defined solely in the DGLAP kinematical region to the ERBL one. We then exemplify our approach using LFWFs models.
[ { "created": "Thu, 19 Dec 2019 10:26:49 GMT", "version": "v1" } ]
2019-12-20
[ [ "Mezrag", "Cédric", "" ], [ "Chouika", "Nabil", "" ], [ "Moutarde", "Hervé", "" ], [ "Rodriguez-Quintero", "Jose", "" ] ]
We present here a new method based on the Radon transform to model Generalised Parton Distributions (GPDs). It allows to fulfil all theoretical constraints applying on GPDs, especially polynomiality and positivity at the same time. More specifically, we show how polynomiality can be systematically restored within the framework of the overlaps of Lightfront Wave Functions (LFWFs). It provides a systematic way to extend models defined solely in the DGLAP kinematical region to the ERBL one. We then exemplify our approach using LFWFs models.
2102.00661
Minoru Tanaka
Minoru Tanaka and Noboru Sasao
Alternative method of generating gamma rays with orbital angular momentum
16 pages, 3 figures. Title changed. Published
null
10.1142/S0218301321500403
OU-HET-1088
hep-ph
http://creativecommons.org/licenses/by-nc-sa/4.0/
We propose a new method of generating gamma rays with orbital angular momentum (OAM). Accelerated partially-stripped ions are used as an energy up-converter. Irradiating an optical laser beam with OAM on ultrarelativistic ions, they are excited to a state of large angular momentum. Gamma rays with OAM are emitted in their deexcitation process. We examine the excitation cross section and deexcitation rate.
[ { "created": "Mon, 1 Feb 2021 06:23:38 GMT", "version": "v1" }, { "created": "Mon, 28 Jun 2021 04:42:10 GMT", "version": "v2" } ]
2021-06-29
[ [ "Tanaka", "Minoru", "" ], [ "Sasao", "Noboru", "" ] ]
We propose a new method of generating gamma rays with orbital angular momentum (OAM). Accelerated partially-stripped ions are used as an energy up-converter. Irradiating an optical laser beam with OAM on ultrarelativistic ions, they are excited to a state of large angular momentum. Gamma rays with OAM are emitted in their deexcitation process. We examine the excitation cross section and deexcitation rate.
1810.01421
Han Gil Choi
Han Gil Choi and Sunghoon Jung
A New Probe of Dark Matter-Induced Fifth Force with Neutron Star Inspirals
12 pages, 3 figures
Phys. Rev. D 99, 015013 (2019)
10.1103/PhysRevD.99.015013
null
hep-ph astro-ph.CO gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A light scalar dark matter (DM) is allowed in a wide range of the mass and interaction types. We show that the light scalar DM may be probed in a new way from final years of neutron-star (NS) binary inspirals. If the DM interacts with the neutron, its long wave coherence in the background can induce the time-oscillating mass shift, to which the binary inspiral is inherently sensitive. But the sensitivity is found to be significantly enhanced by a large number of gravitational-wave (GW) cycles during year-long highest-frequency measurements in the broadband $f \simeq 0.01-1000$ Hz. The future broadband detector networks including LIGO-band detectors can probe unconstrained parameter space of the light scalar DM.
[ { "created": "Tue, 2 Oct 2018 18:00:02 GMT", "version": "v1" }, { "created": "Sun, 6 Jan 2019 09:56:52 GMT", "version": "v2" } ]
2019-01-16
[ [ "Choi", "Han Gil", "" ], [ "Jung", "Sunghoon", "" ] ]
A light scalar dark matter (DM) is allowed in a wide range of the mass and interaction types. We show that the light scalar DM may be probed in a new way from final years of neutron-star (NS) binary inspirals. If the DM interacts with the neutron, its long wave coherence in the background can induce the time-oscillating mass shift, to which the binary inspiral is inherently sensitive. But the sensitivity is found to be significantly enhanced by a large number of gravitational-wave (GW) cycles during year-long highest-frequency measurements in the broadband $f \simeq 0.01-1000$ Hz. The future broadband detector networks including LIGO-band detectors can probe unconstrained parameter space of the light scalar DM.
1009.1683
Aparajita Bhattacharya
A. Bhattacharya, A.Sagari, B.Chakrabarti
Nucleon in Nuclear Matter
null
Int.J.Mod.Phys.2:87,2011
10.4236/jmp.2011.22014
11 pages
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The modification of the properties of nucleon in nuclear medium have been investigated in the context of flux tube model. A nucleon has been described as diquark-quark system connected by flux tube and quasi particle diquark model has been used to describe the diquak constituting the nucleon. The modification of incompressiblity, the roper resonance etc in the nuclear medium have been investigated. The results are compared with recent experimental and theoretical predictions.
[ { "created": "Thu, 9 Sep 2010 04:24:38 GMT", "version": "v1" } ]
2013-09-05
[ [ "Bhattacharya", "A.", "" ], [ "Sagari", "A.", "" ], [ "Chakrabarti", "B.", "" ] ]
The modification of the properties of nucleon in nuclear medium have been investigated in the context of flux tube model. A nucleon has been described as diquark-quark system connected by flux tube and quasi particle diquark model has been used to describe the diquak constituting the nucleon. The modification of incompressiblity, the roper resonance etc in the nuclear medium have been investigated. The results are compared with recent experimental and theoretical predictions.
1205.1214
Xin Liu
Xin Liu, Hsiang-nan Li, and Zhen-Jun Xiao
Implications on $\eta$-$\eta'$-glueball mixing from $B_{d/s} \to J/\Psi \eta^{(')}$ Decays
Improved version, references added, 7 pages, 1 figure
null
10.1103/PhysRevD.86.011501
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We point out that the recent Belle measurements of the $B_{d/s} \to J/\Psi \eta^{(')}$ decays imply large pseudoscalar glueball contents in the $\eta^{(\prime)}$ meson. These decays are studied in the perturbative QCD (PQCD) approach, considering the $\eta$-$\eta'$-$G$ mixing, where $G$ represents the pseudoscalar glueball. It is shown that the PQCD predictions for the $B_{d/s} \to J/\Psi \eta^{(')}$ branching ratios agree well with the data for the mixing angle $\phi_G\approx 30^\circ$ between the flavor-singlet state and the pure pseudoscalar glueball. Extending the formalism to the $\eta$-$\eta'$-$G$-$\eta_c$ tetramixing, the abnormally large observed $B_d\to K\eta'$ branching ratios are also explained. The proposed mixing formalism is applicable to other heavy meson decays into $\eta^{(\prime)}$ mesons, and could be tested by future LHCb and Super-$B$ factory data.
[ { "created": "Sun, 6 May 2012 13:02:40 GMT", "version": "v1" }, { "created": "Wed, 23 May 2012 04:55:33 GMT", "version": "v2" } ]
2015-06-05
[ [ "Liu", "Xin", "" ], [ "Li", "Hsiang-nan", "" ], [ "Xiao", "Zhen-Jun", "" ] ]
We point out that the recent Belle measurements of the $B_{d/s} \to J/\Psi \eta^{(')}$ decays imply large pseudoscalar glueball contents in the $\eta^{(\prime)}$ meson. These decays are studied in the perturbative QCD (PQCD) approach, considering the $\eta$-$\eta'$-$G$ mixing, where $G$ represents the pseudoscalar glueball. It is shown that the PQCD predictions for the $B_{d/s} \to J/\Psi \eta^{(')}$ branching ratios agree well with the data for the mixing angle $\phi_G\approx 30^\circ$ between the flavor-singlet state and the pure pseudoscalar glueball. Extending the formalism to the $\eta$-$\eta'$-$G$-$\eta_c$ tetramixing, the abnormally large observed $B_d\to K\eta'$ branching ratios are also explained. The proposed mixing formalism is applicable to other heavy meson decays into $\eta^{(\prime)}$ mesons, and could be tested by future LHCb and Super-$B$ factory data.
2204.05348
Marcos Rodriguez Cardoso
M. C. Rodriguez
The Minimal Supersymmetric Standard Model (MSSM) with $R$-Parity Violation
17 pages, 1 figure
null
null
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
In this lectures, we give a review about the Minimal Supersymmetric Standard Model (MSSM) with $R$-Parity Violation because it provides an attractive way to generate neutrino masses, lepton mixing angles in acconcordance to present neutrino data.
[ { "created": "Mon, 11 Apr 2022 18:09:58 GMT", "version": "v1" } ]
2022-04-13
[ [ "Rodriguez", "M. C.", "" ] ]
In this lectures, we give a review about the Minimal Supersymmetric Standard Model (MSSM) with $R$-Parity Violation because it provides an attractive way to generate neutrino masses, lepton mixing angles in acconcordance to present neutrino data.
2210.00024
Henning Bahl
Henning Bahl, Marcela Carena, Nina M. Coyle, Aurora Ireland, and Carlos E.M. Wagner
New Tools for Dissecting the General 2HDM
39 pages, 6 figures; v2: matches published version
null
10.1007/JHEP03(2023)165
EFI 22-8, FERMILAB-PUB-22-740-T
hep-ph
http://creativecommons.org/licenses/by/4.0/
Two Higgs doublet models (2HDM) provide the low energy effective field theory (EFT) description in many well motivated extensions of the Standard Model. It is therefore relevant to study their properties, as well as the theoretical constraints on these models. In this article we concentrate on three relevant requirements for the validity of the 2HDM framework, namely the perturbative unitarity bounds, the bounded from below constraints, and the vacuum stability constraints. In this study, we concentrate on the most general renormalizable version of the 2HDM -- without imposing any parity symmetry, which may be violated in many UV extensions. We derive novel analytical expressions that generalize those previously obtained in more restrictive scenarios to the most general case. We also discuss the phenomenological implications of these bounds, focusing on CP violation.
[ { "created": "Fri, 30 Sep 2022 18:01:01 GMT", "version": "v1" }, { "created": "Mon, 1 May 2023 22:00:36 GMT", "version": "v2" } ]
2023-05-03
[ [ "Bahl", "Henning", "" ], [ "Carena", "Marcela", "" ], [ "Coyle", "Nina M.", "" ], [ "Ireland", "Aurora", "" ], [ "Wagner", "Carlos E. M.", "" ] ]
Two Higgs doublet models (2HDM) provide the low energy effective field theory (EFT) description in many well motivated extensions of the Standard Model. It is therefore relevant to study their properties, as well as the theoretical constraints on these models. In this article we concentrate on three relevant requirements for the validity of the 2HDM framework, namely the perturbative unitarity bounds, the bounded from below constraints, and the vacuum stability constraints. In this study, we concentrate on the most general renormalizable version of the 2HDM -- without imposing any parity symmetry, which may be violated in many UV extensions. We derive novel analytical expressions that generalize those previously obtained in more restrictive scenarios to the most general case. We also discuss the phenomenological implications of these bounds, focusing on CP violation.
hep-ph/9711203
Cao Fu-guang
Fu-Guang Cao, Yuan-Ben Dai and Chao-Shang Huang
Twist-3 contribution to the pion electromagnetic form factor
10 pages, 2 fgures, latex. More discussions on the Sudakov effect added, references added. To appear in European Physical Journal C (Zeitschrift fur Physik C)
Eur.Phys.J.C11:501-506,1999
10.1007/s100520050650
null
hep-ph
null
Non-leading contribution to the pion electromagnetic form factor which comes from the pion twist-3 wave function is analyzed in the modified hard scattering approach (MHSA) proposed by Li and Sterman. This contribution is enhanced significantly due to bound state effect (the twist-3 wave function is independent of the fractional momentum carried by the parton and has a large factor $\sim m_\pi^2/m_0$ with $m_\pi$ being the pion meson mass and $m_0$ being the mean u- and d-quark masses). Consequently, although it is suppressed by the factor $1/Q^2$, the twist-3 contribution is comparable with and even larger than the leading twist (twist-2) contribution at intermediate energy region of $Q^2$ being $2 \sim 40 {GeV}^2$.
[ { "created": "Mon, 3 Nov 1997 07:26:45 GMT", "version": "v1" }, { "created": "Mon, 1 Jun 1998 08:16:02 GMT", "version": "v2" } ]
2009-08-25
[ [ "Cao", "Fu-Guang", "" ], [ "Dai", "Yuan-Ben", "" ], [ "Huang", "Chao-Shang", "" ] ]
Non-leading contribution to the pion electromagnetic form factor which comes from the pion twist-3 wave function is analyzed in the modified hard scattering approach (MHSA) proposed by Li and Sterman. This contribution is enhanced significantly due to bound state effect (the twist-3 wave function is independent of the fractional momentum carried by the parton and has a large factor $\sim m_\pi^2/m_0$ with $m_\pi$ being the pion meson mass and $m_0$ being the mean u- and d-quark masses). Consequently, although it is suppressed by the factor $1/Q^2$, the twist-3 contribution is comparable with and even larger than the leading twist (twist-2) contribution at intermediate energy region of $Q^2$ being $2 \sim 40 {GeV}^2$.
2303.01789
Barbara Pasquini
Barbara Pasquini (Pavia U & INFN-Pavia), Simone Rodini (\'Ecole Polytechnique, CPHT), Simone Venturini (Pavia U & INFN-Pavia)
The valence quark, sea, and gluon content of the pion from the parton distribution functions and the electromagnetic form factor
18 pages, 3 figures; typos corrected, one reference added and discussion of the model extended; version to appear in Phys. Rev. D
null
10.1103/PhysRevD.107.114023
null
hep-ph hep-ex nucl-ex nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a light-front model calculation of the pion parton distribution functions (PDFs) and the pion electromagnetic form factor. The pion state is modeled in terms of light-front wave functions (LFWFs) for the $q\bar q$, $q\bar q q\bar q$, $q\bar q g$, and $q\bar q gg$ components. We design the LFWFs so that the parameters in the longitudinal and transverse momentum space enter separately in the fit of the pion PDFs and the electromagnetic form factor, respectively. We extract the pion PDFs within the xFitter framework using available Drell-Yan and photon-production data. With the obtained parameters in the longitudinal-momentum space, we then fit the available experimental data on the pion electromagnetic form factor to constrain the remaining parameters in the transverse-momentum space. The results for the pion PDFs are compatible with existing extractions and lattice calculations, and the fit to the pion electromagnetic form factor data works quite successfully. The obtained parametrization for the LFWFs marks a step forward towards a unified description of different hadron distribution functions in both the longitudinal- and transverse-momentum space and will be further applied to a phenomenological study of transverse-momentum dependent parton distribution functions and generalized parton distributions.
[ { "created": "Fri, 3 Mar 2023 08:57:35 GMT", "version": "v1" }, { "created": "Mon, 12 Jun 2023 20:14:51 GMT", "version": "v2" } ]
2023-06-28
[ [ "Pasquini", "Barbara", "", "Pavia U & INFN-Pavia" ], [ "Rodini", "Simone", "", "École\n Polytechnique, CPHT" ], [ "Venturini", "Simone", "", "Pavia U & INFN-Pavia" ] ]
We present a light-front model calculation of the pion parton distribution functions (PDFs) and the pion electromagnetic form factor. The pion state is modeled in terms of light-front wave functions (LFWFs) for the $q\bar q$, $q\bar q q\bar q$, $q\bar q g$, and $q\bar q gg$ components. We design the LFWFs so that the parameters in the longitudinal and transverse momentum space enter separately in the fit of the pion PDFs and the electromagnetic form factor, respectively. We extract the pion PDFs within the xFitter framework using available Drell-Yan and photon-production data. With the obtained parameters in the longitudinal-momentum space, we then fit the available experimental data on the pion electromagnetic form factor to constrain the remaining parameters in the transverse-momentum space. The results for the pion PDFs are compatible with existing extractions and lattice calculations, and the fit to the pion electromagnetic form factor data works quite successfully. The obtained parametrization for the LFWFs marks a step forward towards a unified description of different hadron distribution functions in both the longitudinal- and transverse-momentum space and will be further applied to a phenomenological study of transverse-momentum dependent parton distribution functions and generalized parton distributions.
hep-ph/9310253
Edward Shuryak
Edward Shuryak (Physics Department, SUNY at Stony Brook, NY and ITP, UCSB, Santa Barbara, CA)
Which chiral symmetry is restored in hot QCD?
null
Comments Nucl.Part.Phys. 21 (1994) 235-248
null
null
hep-ph hep-lat
null
We review the current status of the problem of chiral symmetry restoration, discussing an open question of whether at the $SU(N_f)_A$ restoration point $T=T_c$ the $U(1)_A$ chiral symmetry is or is not (approximately) restored. New lattice and instanton-based studies are considered, and some new calculations are suggested to clarify the issue. We also speculate on possible experimental manifestations of two possible scenarios.
[ { "created": "Fri, 8 Oct 1993 23:11:00 GMT", "version": "v1" } ]
2007-05-23
[ [ "Shuryak", "Edward", "", "Physics Department, SUNY at Stony Brook, NY and ITP,\n UCSB, Santa Barbara, CA" ] ]
We review the current status of the problem of chiral symmetry restoration, discussing an open question of whether at the $SU(N_f)_A$ restoration point $T=T_c$ the $U(1)_A$ chiral symmetry is or is not (approximately) restored. New lattice and instanton-based studies are considered, and some new calculations are suggested to clarify the issue. We also speculate on possible experimental manifestations of two possible scenarios.
1810.05790
Jun Jiang
Jun Jiang, Hao Yang, and Cong-Feng Qiao
Exploring Bosonic Mediator of Interaction at BESIII
To appear in EPJC; 26 pages, 13 figures; Fig.s (5, 6, 9, 11, 12, 13) are reploted and their discussion are updated; three paragraphs, two equations and 1 table are added; two errors are corrected
null
10.1140/epjc/s10052-019-6912-3
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a comprehensive investigation on the possibility of the search for new force mediator $X$ boson in $e^+e^-$ collision and $J/\psi$ decay at the BESIII experiment. The typical interactions of $X$ boson coupling to leptons and quarks are explored. The production and decay properties of this $X$ particle, the product/decay chains $e^+e^-\to X\gamma \to e^+e^-\gamma$ and $J/\psi \to X\gamma\to\mu^+\mu^-\gamma$, and exclusion limits on the reduced coupling strength parameters as functions of $X$ boson mass are presented. With the data set of tens of fb$^{-1}~e^+e^-$ or $10^{10}~J/\psi$, we find that the exclusion limits on the coupling strength parameters fall in the range of $10^{-3}\sim10^{-4}$, depending on $m_X$ assuming the decay width 10 eV$<\Gamma_X<$100 eV reasonably, for various hypotheses in the literature. According to our estimation, the search for new force mediator $X$ boson in both $e^+e^-$ collision and $J/\psi$ decay are accessible in nowadays BESIII experiment.
[ { "created": "Sat, 13 Oct 2018 03:05:39 GMT", "version": "v1" }, { "created": "Sat, 4 May 2019 08:25:24 GMT", "version": "v2" } ]
2019-06-05
[ [ "Jiang", "Jun", "" ], [ "Yang", "Hao", "" ], [ "Qiao", "Cong-Feng", "" ] ]
We present a comprehensive investigation on the possibility of the search for new force mediator $X$ boson in $e^+e^-$ collision and $J/\psi$ decay at the BESIII experiment. The typical interactions of $X$ boson coupling to leptons and quarks are explored. The production and decay properties of this $X$ particle, the product/decay chains $e^+e^-\to X\gamma \to e^+e^-\gamma$ and $J/\psi \to X\gamma\to\mu^+\mu^-\gamma$, and exclusion limits on the reduced coupling strength parameters as functions of $X$ boson mass are presented. With the data set of tens of fb$^{-1}~e^+e^-$ or $10^{10}~J/\psi$, we find that the exclusion limits on the coupling strength parameters fall in the range of $10^{-3}\sim10^{-4}$, depending on $m_X$ assuming the decay width 10 eV$<\Gamma_X<$100 eV reasonably, for various hypotheses in the literature. According to our estimation, the search for new force mediator $X$ boson in both $e^+e^-$ collision and $J/\psi$ decay are accessible in nowadays BESIII experiment.
1901.04746
Shiba Behera
S. P. Behera, D. K. Mishra, and L. M. Pant
Sensitivity to sterile neutrino mixing using reactor antineutrinos
10 pages, 11 figures; Published in Eur.Phys.J. C 79, 86 (2019)
null
10.1140/epjc/s10052-019-6591-0
null
hep-ph nucl-ex nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The reactor antineutrinos are used for the precise measurement of oscillation parameters in the 3-neutrino model, and also used to investigate active-sterile neutrino mixing sensitivity in the 3$+$1 neutrino framework. In the present work, we study the feasibility of sterile neutrino search with the Indian Scintillator Matrix for Reactor Anti-Neutrino (ISMRAN) experimental set-up using electron antineutrinos ($\overline{\nu}_e$) produced from reactor as a source. The so-called 3$+$1 scenario is considered for active-sterile neutrino mixing, which leads to projected exclusion curves in the sterile neutrino mass and mixing angle plane. The analysis is performed considering both the reactor and detector related parameters. It is found that, the ISMRAN set-up can observe the active-sterile neutrino mixing sensitivity for $\sin^{2}2\theta_{14} \geq$ 0.064 and $\Delta m^{2}_{41}$ = 1.0 eV$^2$ at 90$\%$ confidence level for an exposure of 1 ton-year by using neutrinos produced from the DHRUVA reactor with thermal power of 100 MW$_{th}$. It is also observed that, there is a significant improvement of the active-sterile neutrino mixing parameter $\sin^{2}2\theta_{14}$ to $\sim$ 0.03 at the same $\Delta m^{2}_{41}$ by putting the ISMRAN detector set-up at a distance of 20 m from the compact proto-type fast breeder reactor (PFBR) facility with thermal power of 1250 MW$_{th}$.
[ { "created": "Tue, 15 Jan 2019 10:22:06 GMT", "version": "v1" }, { "created": "Mon, 4 Feb 2019 12:26:11 GMT", "version": "v2" } ]
2019-02-05
[ [ "Behera", "S. P.", "" ], [ "Mishra", "D. K.", "" ], [ "Pant", "L. M.", "" ] ]
The reactor antineutrinos are used for the precise measurement of oscillation parameters in the 3-neutrino model, and also used to investigate active-sterile neutrino mixing sensitivity in the 3$+$1 neutrino framework. In the present work, we study the feasibility of sterile neutrino search with the Indian Scintillator Matrix for Reactor Anti-Neutrino (ISMRAN) experimental set-up using electron antineutrinos ($\overline{\nu}_e$) produced from reactor as a source. The so-called 3$+$1 scenario is considered for active-sterile neutrino mixing, which leads to projected exclusion curves in the sterile neutrino mass and mixing angle plane. The analysis is performed considering both the reactor and detector related parameters. It is found that, the ISMRAN set-up can observe the active-sterile neutrino mixing sensitivity for $\sin^{2}2\theta_{14} \geq$ 0.064 and $\Delta m^{2}_{41}$ = 1.0 eV$^2$ at 90$\%$ confidence level for an exposure of 1 ton-year by using neutrinos produced from the DHRUVA reactor with thermal power of 100 MW$_{th}$. It is also observed that, there is a significant improvement of the active-sterile neutrino mixing parameter $\sin^{2}2\theta_{14}$ to $\sim$ 0.03 at the same $\Delta m^{2}_{41}$ by putting the ISMRAN detector set-up at a distance of 20 m from the compact proto-type fast breeder reactor (PFBR) facility with thermal power of 1250 MW$_{th}$.
0901.0770
Stanley J. Brodsky
Stanley J. Brodsky and Guy de Teramond
Light-Front Holography and QCD Hadronization at the Amplitude Level
Talk presented by SJB at the International Conference on Particles and Nuclei (PANIC08), Eilat, Israel, November 9-14, 2008
null
null
SLAC-PUB-13504
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Light-front holography allows hadronic amplitudes in the AdS/QCD fifth dimension to be mapped to frame-independent light-front wavefunctions of hadrons in physical space-time, thus providing a relativistic description of hadrons at the amplitude level. The AdS coordinate z is identified with an invariant light-front coordinate zeta which separates the dynamics of quark and gluon binding from the kinematics of constituent spin and internal orbital angular momentum. The result is a single-variable light-front Schrodinger equation for QCD which determines the eigenspectrum and the light-front wavefunctions of hadrons for general spin and orbital angular momentum. A new method for computing the hadronization of quark and gluon jets at the amplitude level using AdS/QCD light-front wavefunctions is outlined.
[ { "created": "Wed, 7 Jan 2009 08:06:19 GMT", "version": "v1" } ]
2009-01-08
[ [ "Brodsky", "Stanley J.", "" ], [ "de Teramond", "Guy", "" ] ]
Light-front holography allows hadronic amplitudes in the AdS/QCD fifth dimension to be mapped to frame-independent light-front wavefunctions of hadrons in physical space-time, thus providing a relativistic description of hadrons at the amplitude level. The AdS coordinate z is identified with an invariant light-front coordinate zeta which separates the dynamics of quark and gluon binding from the kinematics of constituent spin and internal orbital angular momentum. The result is a single-variable light-front Schrodinger equation for QCD which determines the eigenspectrum and the light-front wavefunctions of hadrons for general spin and orbital angular momentum. A new method for computing the hadronization of quark and gluon jets at the amplitude level using AdS/QCD light-front wavefunctions is outlined.
hep-ph/9603218
Nestor Armesto Perez
N. Armesto and M. A. Braun
On the odderon intercept in perturbative QCD
LaTeX, 19 pages plus 1 postscript figure; some small change in the introduction
Z.Phys. C75 (1997) 709-716
null
US-FT/7-96
hep-ph
null
Arguments are presented for the odderon intercept being exactly equal to unity. A variational method is presented based on a complete system of one-gluon functions. For the odderon, the highest intercept calculated by this method is $1-(3\alpha_{s}/\pi)\,0.45$.
[ { "created": "Mon, 4 Mar 1996 19:54:44 GMT", "version": "v1" }, { "created": "Wed, 13 Mar 1996 18:27:27 GMT", "version": "v2" } ]
2008-02-03
[ [ "Armesto", "N.", "" ], [ "Braun", "M. A.", "" ] ]
Arguments are presented for the odderon intercept being exactly equal to unity. A variational method is presented based on a complete system of one-gluon functions. For the odderon, the highest intercept calculated by this method is $1-(3\alpha_{s}/\pi)\,0.45$.
1209.1149
Pol Bernard Gossiaux
Marcus Bluhm, Pol Bernard Gossiaux, Thierry Gousset and Joerg Aichelin
Radiative energy loss in the absorptive QGP: taming the long formation lengths in coherent emission
contribution to the International Meeting "Excited QCD", Peniche, Portugal, 06 - 12 May 2012
null
null
null
hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In an absorptive plasma, damping of radiation mechanisms can influence the bremsstrahlung formation in case of large radiation formation lengths. We study qualitatively the influence of this effect on the gluon bremsstrahlung spectrum off heavy quarks in the quark-gluon plasma. Independent of the heavy-quark mass, the spectrum is found to be strongly suppressed in an intermediate gluon energy region which grows with increasing gluon damping rate and increasing energy of the heavy quark. Thus, just as polarization effects in the plasma render the bremsstrahlung spectra independent of the quark mass in the soft gluon regime, damping effects tend to have a similar impact for larger gluon energies.
[ { "created": "Thu, 6 Sep 2012 00:41:18 GMT", "version": "v1" } ]
2012-09-07
[ [ "Bluhm", "Marcus", "" ], [ "Gossiaux", "Pol Bernard", "" ], [ "Gousset", "Thierry", "" ], [ "Aichelin", "Joerg", "" ] ]
In an absorptive plasma, damping of radiation mechanisms can influence the bremsstrahlung formation in case of large radiation formation lengths. We study qualitatively the influence of this effect on the gluon bremsstrahlung spectrum off heavy quarks in the quark-gluon plasma. Independent of the heavy-quark mass, the spectrum is found to be strongly suppressed in an intermediate gluon energy region which grows with increasing gluon damping rate and increasing energy of the heavy quark. Thus, just as polarization effects in the plasma render the bremsstrahlung spectra independent of the quark mass in the soft gluon regime, damping effects tend to have a similar impact for larger gluon energies.
hep-ph/0505143
Marcos Andre Betemps
M. A. Betemps (CAVG/UFPel and High Energy Physics Phenomenology Group, GFPAE), M. B. Gay Ducati (High Energy Physics Phenomenology Group, GFPAE)
Using dileptons to probe the Color Glass Condensate
5 pages, version to appear in Phys. Lett. B
null
10.1016/j.physletb.2006.03.021
null
hep-ph
null
The rapidity and transverse momentum dependence of the nuclear modification ratio for dilepton production at RHIC and LHC is presented, calculated in the Color Glass Condensate (CGC) framework. The transverse momentum ratio is compared for two distinct dilepton mass values and a suppression of the Cronin peak is verified even for large mass. The nuclear modification ratio suppression in the dilepton rapidity spectra, as obtained experimentally for hadrons at RHIC, is verified for LHC energies at large transverse momentum, although not present at RHIC energies. The ratio between LHC and RHIC nuclear modification ratios is evaluated in the CGC, showing the large saturation effects at LHC compared with the RHIC results. These results consolidate the dilepton as a most suitable observable to investigate the QCD high density approaches.
[ { "created": "Mon, 16 May 2005 19:42:28 GMT", "version": "v1" }, { "created": "Mon, 17 Apr 2006 13:43:08 GMT", "version": "v2" } ]
2009-11-11
[ [ "Betemps", "M. A.", "", "CAVG/UFPel and High Energy Physics Phenomenology Group,\n GFPAE" ], [ "Ducati", "M. B. Gay", "", "High Energy Physics Phenomenology Group, GFPAE" ] ]
The rapidity and transverse momentum dependence of the nuclear modification ratio for dilepton production at RHIC and LHC is presented, calculated in the Color Glass Condensate (CGC) framework. The transverse momentum ratio is compared for two distinct dilepton mass values and a suppression of the Cronin peak is verified even for large mass. The nuclear modification ratio suppression in the dilepton rapidity spectra, as obtained experimentally for hadrons at RHIC, is verified for LHC energies at large transverse momentum, although not present at RHIC energies. The ratio between LHC and RHIC nuclear modification ratios is evaluated in the CGC, showing the large saturation effects at LHC compared with the RHIC results. These results consolidate the dilepton as a most suitable observable to investigate the QCD high density approaches.
0812.4716
Alexander Studenikin
Alexander Studenikin
Neutrino magnetic moment: a window to new physics
based on the talk presented at the Neutrino Oscillation Workshop, Conca Specchiulla (Otranto, Italy) September 6-13, 2008, to apper in Nucl.Phys.B (Proc.Suppl.)
Nucl.Phys.Proc.Suppl.188:220-222,2009
10.1016/j.nuclphysbps.2009.02.053
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A short review on a neutrino magnetic moment is presented.
[ { "created": "Fri, 26 Dec 2008 22:15:16 GMT", "version": "v1" } ]
2009-04-17
[ [ "Studenikin", "Alexander", "" ] ]
A short review on a neutrino magnetic moment is presented.
hep-ph/0405031
Sabine Hossenfelder
S.Hossenfelder, M.Bleicher and H.Stocker
Signatures of Large Extra Dimensions
8 pages, no figures, Talk presented at the NATO Advanced Study Institute: Structure and Dynamics of Elementary Matter, Kemer, Turkey, 22 Sep - 2 Oct 2003. Proceedings to be published by Kluwer Academic publishers
null
10.1142/S0218271804005687
null
hep-ph
null
String theory suggests modifications of our spacetime such as extra dimensions and the existence of a mininal length scale. In models with addidional dimensions, the Planck scale can be lowered to values accessible by future colliders. Effective theories which extend beyond the standart-model by including extra dimensions and a minimal length allow computation of observables and can be used to make testable predictions. Expected effects that arise within these models are the production of gravitons and black holes. Furthermore, the Planck-length is a lower bound to the possible resolution of spacetime which might be reached soon.
[ { "created": "Tue, 4 May 2004 21:44:19 GMT", "version": "v1" } ]
2009-11-10
[ [ "Hossenfelder", "S.", "" ], [ "Bleicher", "M.", "" ], [ "Stocker", "H.", "" ] ]
String theory suggests modifications of our spacetime such as extra dimensions and the existence of a mininal length scale. In models with addidional dimensions, the Planck scale can be lowered to values accessible by future colliders. Effective theories which extend beyond the standart-model by including extra dimensions and a minimal length allow computation of observables and can be used to make testable predictions. Expected effects that arise within these models are the production of gravitons and black holes. Furthermore, the Planck-length is a lower bound to the possible resolution of spacetime which might be reached soon.
hep-ph/0005081
Francesco Murgia
M. Anselmino (1), M. Boglione (2), F. Murgia (3) ((1) University and INFN, Torino, Italy, (2) Vrije Universiteit, Amsterdam, The Netherlands, (3) University and INFN, Cagliari, Italy)
Phenomenology of transverse single spin asymmetries in inclusive processes
LaTeX, 11 pages + 2 ps figures, uses epsfig.sty. Talk delivered by M. Anselmino at the Fifth Workshop on Quantum Chromodynamics, January 3-7, 2000, Villefranche, France
null
null
DFTT 18/2000, INFNCA-TH0008, VUTH 00-13
hep-ph
null
A phenomenological description of single transverse spin asymmetries for the inclusive production of hadrons in proton-proton and lepton-proton processes is discussed within pQCD and a straightforward generalization of the factorization theorem with the inclusion of parton intrinsic transverse motion. Fits to existing data, predictions for new processes and interpretation of recent results are presented.
[ { "created": "Tue, 9 May 2000 15:38:35 GMT", "version": "v1" } ]
2007-05-23
[ [ "Anselmino", "M.", "" ], [ "Boglione", "M.", "" ], [ "Murgia", "F.", "" ] ]
A phenomenological description of single transverse spin asymmetries for the inclusive production of hadrons in proton-proton and lepton-proton processes is discussed within pQCD and a straightforward generalization of the factorization theorem with the inclusion of parton intrinsic transverse motion. Fits to existing data, predictions for new processes and interpretation of recent results are presented.
hep-ph/0507323
Schweizer Julia
J. Schweizer (Vienna U.)
Isospin odd pi K scattering length
11 pages
Phys.Lett.B625:217-224,2005
10.1016/j.physletb.2005.08.058
UWThPh-2005-12
hep-ph
null
We make use of the chiral two-loop representation of the pi K scattering amplitude [J. Bijnens, P. Dhonte and P. Talavera, JHEP 0405 (2004) 036] to investigate the isospin odd scattering length at next-to-next-to-leading order in the SU(3) expansion. This scattering length is protected against contributions of m_s in the chiral expansion, in the sense that the corrections to the current algebra result are of order M_pi^2. In view of the planned lifetime measurement on pi K atoms at CERN it is important to understand the size of these corrections.
[ { "created": "Thu, 28 Jul 2005 13:16:10 GMT", "version": "v1" } ]
2011-07-19
[ [ "Schweizer", "J.", "", "Vienna U." ] ]
We make use of the chiral two-loop representation of the pi K scattering amplitude [J. Bijnens, P. Dhonte and P. Talavera, JHEP 0405 (2004) 036] to investigate the isospin odd scattering length at next-to-next-to-leading order in the SU(3) expansion. This scattering length is protected against contributions of m_s in the chiral expansion, in the sense that the corrections to the current algebra result are of order M_pi^2. In view of the planned lifetime measurement on pi K atoms at CERN it is important to understand the size of these corrections.
hep-ph/0205014
Carlo Giunti
C. Giunti
Neutrino Wave Packets in Quantum Field Theory
25 pages
JHEP 0211:017,2002
10.1088/1126-6708/2002/11/017
null
hep-ph
null
We present a model of neutrino oscillations in the framework of quantum field theory in which the propagating neutrino and the particles participating to the production and detection processes are described by wave packets. The neutrino state is a superposition of massive neutrino wave packets determined by the production process, as naturally expected from causality. We show that the energies and momenta of the massive neutrino components relevant for neutrino oscillations are in general different from the average energies and momenta of the propagating massive neutrino wave packets, because of the effects of the detection process. Our results confirm the correctness of the standard expression for the oscillation length of extremely relativistic neutrinos and the existence of a coherence length.
[ { "created": "Thu, 2 May 2002 08:47:02 GMT", "version": "v1" }, { "created": "Wed, 26 Jun 2002 14:05:33 GMT", "version": "v2" } ]
2011-07-18
[ [ "Giunti", "C.", "" ] ]
We present a model of neutrino oscillations in the framework of quantum field theory in which the propagating neutrino and the particles participating to the production and detection processes are described by wave packets. The neutrino state is a superposition of massive neutrino wave packets determined by the production process, as naturally expected from causality. We show that the energies and momenta of the massive neutrino components relevant for neutrino oscillations are in general different from the average energies and momenta of the propagating massive neutrino wave packets, because of the effects of the detection process. Our results confirm the correctness of the standard expression for the oscillation length of extremely relativistic neutrinos and the existence of a coherence length.
1605.06765
Kenji Morita
Kenji Morita, Akira Ohnishi, Faisal Etminan, Tetsuo Hatsuda
Probing Multi-Strange Dibaryon with Proton-Omega Correlation in High-energy Heavy Ion Collisions
6 pages, 5 figures, to appear in Phys. Rev. C (Rapid Communication)
Phys. Rev. C 94, 031901 (2016)
10.1103/PhysRevC.94.031901
YITP-16-62, RIKEN-QHP-223
hep-ph nucl-ex nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Two-particle intensity correlation between the proton ($p$) and the Omega-baryon ($\Omega$) in high-energy heavy ion collisions is studied to unravel the possible spin-2 $p\Omega$ dibaryon recently suggested by lattice QCD simulations. The ratio of correlation functions between small and large collision systems, $C_{\rm SL}(Q)$, is proposed to be a new measure to extract the strong $p\Omega$ interaction without much contamination from the Coulomb attraction. Relevance of this quantity to the experimental observables in heavy-ion collisions is also discussed.
[ { "created": "Sun, 22 May 2016 09:56:42 GMT", "version": "v1" }, { "created": "Tue, 30 Aug 2016 06:00:05 GMT", "version": "v2" } ]
2016-09-14
[ [ "Morita", "Kenji", "" ], [ "Ohnishi", "Akira", "" ], [ "Etminan", "Faisal", "" ], [ "Hatsuda", "Tetsuo", "" ] ]
Two-particle intensity correlation between the proton ($p$) and the Omega-baryon ($\Omega$) in high-energy heavy ion collisions is studied to unravel the possible spin-2 $p\Omega$ dibaryon recently suggested by lattice QCD simulations. The ratio of correlation functions between small and large collision systems, $C_{\rm SL}(Q)$, is proposed to be a new measure to extract the strong $p\Omega$ interaction without much contamination from the Coulomb attraction. Relevance of this quantity to the experimental observables in heavy-ion collisions is also discussed.
hep-ph/9306307
Juergen Baacke
J. Baacke and S. Junker
Quantum Corrections to the Electroweak Sphaleron Transition
6pages, 2 figures (appended as uuencoded tar-compressed postscript files),DO-TH-93/15
Mod. Phys. Lett. A8 (1993) 2869-2874
10.1142/S0217732393003251
null
hep-ph
null
We have performed a new exact evaluation of the fluctuation determinant $\kappa$ of the electroweak sphaleron with $\Theta _W =0$. The results differ significantly from a previous calculation of this quantity by Carson et. al. . We find that $\kappa$ is of order 1 in units $(gv)^6$ while the previous results indicated a strong suppression of the sphaleron transition by this factor.
[ { "created": "Wed, 23 Jun 1993 17:11:28 GMT", "version": "v1" } ]
2015-06-25
[ [ "Baacke", "J.", "" ], [ "Junker", "S.", "" ] ]
We have performed a new exact evaluation of the fluctuation determinant $\kappa$ of the electroweak sphaleron with $\Theta _W =0$. The results differ significantly from a previous calculation of this quantity by Carson et. al. . We find that $\kappa$ is of order 1 in units $(gv)^6$ while the previous results indicated a strong suppression of the sphaleron transition by this factor.
hep-ph/9708419
null
JoAnne L. Hewett and Thomas G. Rizzo
Don't Stop Thinking About Leptoquarks: Constructing New Models
Modified text, added table, and updated references
Phys.Rev. D58 (1998) 055005
10.1103/PhysRevD.58.055005
SLAC-PUB-7549
hep-ph
null
We discuss the general framework for the construction of new models containing a single, fermion number zero scalar leptoquark of mass $\simeq 200-220$ GeV which can both satisfy the D0/CDF search constraints as well as low energy data, and can lead to both neutral and charged current-like final states at HERA. The class of models of this kind necessarily contain new vector-like fermions with masses at the TeV scale which mix with those of the Standard Model after symmetry breaking. In this paper we classify all models of this type and examine their phenomenological implications as well as their potential embedding into SUSY and non-SUSY GUT scenarios. The general coupling parameter space allowed by low energy as well as collider data for these models is described and requires no fine-tuning of the parameters.
[ { "created": "Wed, 20 Aug 1997 23:48:52 GMT", "version": "v1" }, { "created": "Wed, 12 Nov 1997 05:24:03 GMT", "version": "v2" } ]
2009-10-30
[ [ "Hewett", "JoAnne L.", "" ], [ "Rizzo", "Thomas G.", "" ] ]
We discuss the general framework for the construction of new models containing a single, fermion number zero scalar leptoquark of mass $\simeq 200-220$ GeV which can both satisfy the D0/CDF search constraints as well as low energy data, and can lead to both neutral and charged current-like final states at HERA. The class of models of this kind necessarily contain new vector-like fermions with masses at the TeV scale which mix with those of the Standard Model after symmetry breaking. In this paper we classify all models of this type and examine their phenomenological implications as well as their potential embedding into SUSY and non-SUSY GUT scenarios. The general coupling parameter space allowed by low energy as well as collider data for these models is described and requires no fine-tuning of the parameters.
1301.1078
Xiao-Gang He
Guan-Nan Li, Hsiu-Hsien Lin, Dong Xu, Xiao-Gang He
The $\beta$ angle as the CP violating phase in the CKM matrix
RevTex 7 pages with one figure. Version to be published in Phys. Lett. B. arXiv admin note: substantial text overlap with arXiv:1204.1230
null
10.1016/j.physletb.2012.12.067
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The CKM matrix describing quark mixing with three generations can be parameterized by three Euler mixing angles and one CP violating phase. In most of the parameterizations, the CP violating phase chosen is not a directly measurable quantity and is parametrization dependent. In this work, we propose to use the most accurately measured CP violating angle $\beta$ in the unitarity triangleas the phase in the CKM matrix, and construct an explicit $\beta$ parameterization. We also derive an approximate Wolfenstein-like expression for this parameterization.
[ { "created": "Sun, 6 Jan 2013 23:46:04 GMT", "version": "v1" } ]
2015-06-12
[ [ "Li", "Guan-Nan", "" ], [ "Lin", "Hsiu-Hsien", "" ], [ "Xu", "Dong", "" ], [ "He", "Xiao-Gang", "" ] ]
The CKM matrix describing quark mixing with three generations can be parameterized by three Euler mixing angles and one CP violating phase. In most of the parameterizations, the CP violating phase chosen is not a directly measurable quantity and is parametrization dependent. In this work, we propose to use the most accurately measured CP violating angle $\beta$ in the unitarity triangleas the phase in the CKM matrix, and construct an explicit $\beta$ parameterization. We also derive an approximate Wolfenstein-like expression for this parameterization.
2204.07334
Purushottam Sahu
Pritam Kumar Bishee, Purushottam Sahu and Sudhanwa Patra
Effect of right-handed currents and dark side of the solar neutrino parameter space to Neutrinoless Double Beta Decay
6 pages, 2 figures
STUDENT JOURNAL OF PHYSICS 2018 Vol. 7, No. 4 Oct-Dec. 2018
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Majorana nature of neutrinos will be the confirmed by the observation of the rare process called as neutrinoless double beta decay process, i.e. the simultaneous decay of two neutrons in the nucleus of an isotope (A, Z) into two protons and two electrons without the emission of any neutrinos i.e, $(A, Z) \to (A, Z + 2) + 2 e^-$. The non-observation of such a decay so far has been interpreted as a lower limit on the half life of the isotope under investigation, which puts severe constraints on any new physics giving rise to LNV in the electron sector. On the other hand, the standard mechanism with normal ordering and inverted ordering can not saturate the present experimental limit while quasi-degenerate light neutrinos are strongly disfavored by the upper limits on the sum of light neutrino masses from cosmological data sets. In this work, we show that how dark side of the solar neutrino parameter space and effect of new physics contributions from right-handed currents can saturate the experimental limit provided by KamLAND-Zen and GERDA.
[ { "created": "Fri, 15 Apr 2022 05:18:39 GMT", "version": "v1" }, { "created": "Tue, 26 Apr 2022 11:55:21 GMT", "version": "v2" } ]
2022-04-27
[ [ "Bishee", "Pritam Kumar", "" ], [ "Sahu", "Purushottam", "" ], [ "Patra", "Sudhanwa", "" ] ]
The Majorana nature of neutrinos will be the confirmed by the observation of the rare process called as neutrinoless double beta decay process, i.e. the simultaneous decay of two neutrons in the nucleus of an isotope (A, Z) into two protons and two electrons without the emission of any neutrinos i.e, $(A, Z) \to (A, Z + 2) + 2 e^-$. The non-observation of such a decay so far has been interpreted as a lower limit on the half life of the isotope under investigation, which puts severe constraints on any new physics giving rise to LNV in the electron sector. On the other hand, the standard mechanism with normal ordering and inverted ordering can not saturate the present experimental limit while quasi-degenerate light neutrinos are strongly disfavored by the upper limits on the sum of light neutrino masses from cosmological data sets. In this work, we show that how dark side of the solar neutrino parameter space and effect of new physics contributions from right-handed currents can saturate the experimental limit provided by KamLAND-Zen and GERDA.
hep-ph/0002017
Paul H. Frampton
Paul H. Frampton
Bilepton Resonance in Electron-Electron Scattering
9 pages LaTeX. Talk at Third International Workshop on Electron-Electron Interactions at TeV Energies, UC-Santa Cruz. December 10-12, 1999
Int.J.Mod.Phys.A15:2455-2460,2000
10.1142/S0217751X00002524
IFP-782-UNC
hep-ph
null
Theoretical backgound for bileptonic gauge bosons is reviewed, both the SU(15) GUT model and the 3-3-1 model. Mass limits on bileptons are discussed coming from $e^+e^-$ scattering, polarized muon decay and muonium-antimuonium conversion. Discovery in $e^-e^-$ at a linear collider at low energy (100GeV) and high luminosity ($10^{33}/cm^2/s$) is emphasised.}
[ { "created": "Tue, 1 Feb 2000 22:02:23 GMT", "version": "v1" } ]
2015-06-25
[ [ "Frampton", "Paul H.", "" ] ]
Theoretical backgound for bileptonic gauge bosons is reviewed, both the SU(15) GUT model and the 3-3-1 model. Mass limits on bileptons are discussed coming from $e^+e^-$ scattering, polarized muon decay and muonium-antimuonium conversion. Discovery in $e^-e^-$ at a linear collider at low energy (100GeV) and high luminosity ($10^{33}/cm^2/s$) is emphasised.}
hep-ph/0408270
Gi-Chol Cho
Gi-Chol Cho, Aya Omote (Ochanomizu Univ.)
Search for extra gauge bosons in Little Higgs models at a linear collider
4 pages, 2 figures. Talk given at the International Conference on Linear Colliders, LCWS04, 19-23 April 2004, Paris, France
null
null
OCHA-PP-233
hep-ph
null
A generic feature of little Higgs models is presence of extra neutral gauge bosons. In the littlest Higgs model, the neutral extra gauge boson A_H is lightest among the extra particles and could be as light as a few hundred GeV, which may be produced directly at an e^+ e^- linear collider. We study production and decay of A_H at the linear collider and compare them with those of Z' bosons in supersymmetric E_6 models.
[ { "created": "Wed, 25 Aug 2004 05:02:05 GMT", "version": "v1" } ]
2007-05-23
[ [ "Cho", "Gi-Chol", "", "Ochanomizu Univ." ], [ "Omote", "Aya", "", "Ochanomizu Univ." ] ]
A generic feature of little Higgs models is presence of extra neutral gauge bosons. In the littlest Higgs model, the neutral extra gauge boson A_H is lightest among the extra particles and could be as light as a few hundred GeV, which may be produced directly at an e^+ e^- linear collider. We study production and decay of A_H at the linear collider and compare them with those of Z' bosons in supersymmetric E_6 models.
hep-ph/0310300
Karol Kolodziej
K. Cieckiewicz, K. Kolodziej (University of Silesia)
Top quark pair production at a linear collider in the presence of an anomalous Wtb coupling
6 pages, 4 figures, presented by K. Cieckiewicz at the XXVII International Coference of Theoretical Physics "Matter to the Deepest: Recent Developments in Physics of Fundamental Interactions", Ustron, Poland, September 15-21, 2003
Acta Phys.Polon. B34 (2003) 5497-5502
null
null
hep-ph
null
Angular distributions of a mu+ and a b-quark resulting from the decay of a top quark produced at the e+e- linear collider with an unpolarized and a 100% longitudinally polarized electron beam are presented. The results of the standard model are compared with the results obtained in the presence of the anomalous Wtb coupling.
[ { "created": "Mon, 27 Oct 2003 17:22:23 GMT", "version": "v1" }, { "created": "Mon, 3 Nov 2003 15:00:09 GMT", "version": "v2" } ]
2007-05-23
[ [ "Cieckiewicz", "K.", "", "University of Silesia" ], [ "Kolodziej", "K.", "", "University of Silesia" ] ]
Angular distributions of a mu+ and a b-quark resulting from the decay of a top quark produced at the e+e- linear collider with an unpolarized and a 100% longitudinally polarized electron beam are presented. The results of the standard model are compared with the results obtained in the presence of the anomalous Wtb coupling.
1901.09862
Qixin Yu
Q. X. Yu, W. H. Liang, M. Bayar and E. Oset
Line shape and $D^{(\ast)}\bar D^{(\ast)}$ probabilities of $\psi(3770)$ from the $e^+e^-\to D\bar D$ reaction
30 pages, 12 figures
Phys. Rev. D 99, 076002 (2019)
10.1103/PhysRevD.99.076002
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We have performed a calculation of the $D\bar D$, $D\bar D^\ast$, $D^\ast\bar D$, $D^\ast\bar D^\ast$ components in the wave function of the $\psi(3770)$. For this we make use of the $^3P_0$ model to find the coupling of $\psi(3770)$ to these components, that with an elaborate angular momentum algebra can be obtained with only one parameter. Then we use data for the $e^+e^-\to D\bar D$ reaction, from where we determine a form factor needed in the theoretical frame work, as well as other parameters needed to evaluate the meson-meson selfenergy of the $\psi(3770)$. Once this is done we determine the $Z$ probability to still have a vector core and the probability to have the different meson components. We find $Z$ about $80\sim85\%$, and the individual meson-meson components are rather small, providing new empirical information to support the largely $q\bar q$ component of vector mesons, and the $\psi(3770)$ in particular.
[ { "created": "Mon, 28 Jan 2019 18:08:52 GMT", "version": "v1" } ]
2019-04-10
[ [ "Yu", "Q. X.", "" ], [ "Liang", "W. H.", "" ], [ "Bayar", "M.", "" ], [ "Oset", "E.", "" ] ]
We have performed a calculation of the $D\bar D$, $D\bar D^\ast$, $D^\ast\bar D$, $D^\ast\bar D^\ast$ components in the wave function of the $\psi(3770)$. For this we make use of the $^3P_0$ model to find the coupling of $\psi(3770)$ to these components, that with an elaborate angular momentum algebra can be obtained with only one parameter. Then we use data for the $e^+e^-\to D\bar D$ reaction, from where we determine a form factor needed in the theoretical frame work, as well as other parameters needed to evaluate the meson-meson selfenergy of the $\psi(3770)$. Once this is done we determine the $Z$ probability to still have a vector core and the probability to have the different meson components. We find $Z$ about $80\sim85\%$, and the individual meson-meson components are rather small, providing new empirical information to support the largely $q\bar q$ component of vector mesons, and the $\psi(3770)$ in particular.
hep-ph/0009313
E. Martynov
P. Desgrolard, A. Lengyel, E. Martynov
Damping of the HERA effect in DIS?
14 pages (LaTeX) including 7 figures, misprints are corrected
Nucl.Phys.Proc.Suppl.99A:168-171,2001
10.1016/S0920-5632(01)01328-7
LYCEN 2000-93 (IPNL, Lyon, France)
hep-ph hep-ex
null
The drastic rise of the proton structure function F_2(x,Q^2) when the Bj\"orken variable x decreases, seen at HERA for a large span of Q^2, negative values for the 4-momentum transfer, may be damped when Q^2 increases beyond several hundreds GeV^2. A new data analysis and a comparison with recent models for the proton structure function is proposed to discuss this phenomenon in terms of the derivative \partial ln F_2(x,Q^2)/\partial ln(1/x).
[ { "created": "Wed, 27 Sep 2000 13:29:22 GMT", "version": "v1" }, { "created": "Mon, 2 Oct 2000 09:32:18 GMT", "version": "v2" } ]
2014-11-17
[ [ "Desgrolard", "P.", "" ], [ "Lengyel", "A.", "" ], [ "Martynov", "E.", "" ] ]
The drastic rise of the proton structure function F_2(x,Q^2) when the Bj\"orken variable x decreases, seen at HERA for a large span of Q^2, negative values for the 4-momentum transfer, may be damped when Q^2 increases beyond several hundreds GeV^2. A new data analysis and a comparison with recent models for the proton structure function is proposed to discuss this phenomenon in terms of the derivative \partial ln F_2(x,Q^2)/\partial ln(1/x).
1707.04534
Arkaitz Rodas
A.Rodas (U. Complutense, Madrid)
Analytic approach to pion-kaon scattering and strange resonances
Proceedings of the Excited QCD 2017 Workshop, Sintra, Portugal, May 2017
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We review our analysis of $\pi K$ scattering using forward dispersion relations. The method yields a set of simple parameterizations that are compatible with forward dispersion relations up to 1.6 GeV while still describing the data. Once the partial waves are obtained, we calculate the poles in the complex plane by means of Pad\'e approximants, thus avoiding a particular model for the pole parameterization. The resonances calculated below 1.8 GeV are the much debated scalar $\kappa$-meson, nowadays known as $K_0^*(800)$, the scalar $K_0^*(1430)$, the $K^*(892)$ and $K_1^*(1410)$ vectors, the spin-two $K_2^*(1430)$ as well as the spin-three $K^*_3(1780)$.
[ { "created": "Fri, 14 Jul 2017 15:09:13 GMT", "version": "v1" } ]
2017-07-17
[ [ "Rodas", "A.", "", "U. Complutense, Madrid" ] ]
We review our analysis of $\pi K$ scattering using forward dispersion relations. The method yields a set of simple parameterizations that are compatible with forward dispersion relations up to 1.6 GeV while still describing the data. Once the partial waves are obtained, we calculate the poles in the complex plane by means of Pad\'e approximants, thus avoiding a particular model for the pole parameterization. The resonances calculated below 1.8 GeV are the much debated scalar $\kappa$-meson, nowadays known as $K_0^*(800)$, the scalar $K_0^*(1430)$, the $K^*(892)$ and $K_1^*(1410)$ vectors, the spin-two $K_2^*(1430)$ as well as the spin-three $K^*_3(1780)$.
1511.01160
Cheng-Yang Lee
Marco Dias and Cheng-Yang Lee
Constraints on mass dimension one fermionic dark matter from the Yukawa interaction
14 pages, 3 figures. Results clarified
Phys. Rev. D 94, 065020 (2016)
10.1103/PhysRevD.94.065020
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the loop corrections to the scalar propagator and the fermionic self-energy for the mass dimension one fermionic dark matter with the Yukawa interaction. We find, in the former case, there is a non-vanishing Lorentz-violating term while the later is Lorentz-invariant. Our study of the fermionic loop correction shows that unitarity demands the fermionic mass must be at least half of the bosonic mass and that the Lorentz-violating term makes a non-trivial correction to the bosonic propagator. We discuss what these results mean in the context of the Standard Model and the possibility of bypassing the unitarity constraint. In the simplest scenario, within the framework of standard quantum field theory, by identifying the scalar boson to be the Higgs boson with a mass of 125 GeV, the mass of the fermion must be at least 62.5 GeV.
[ { "created": "Tue, 3 Nov 2015 23:31:32 GMT", "version": "v1" }, { "created": "Thu, 5 Nov 2015 18:09:50 GMT", "version": "v2" }, { "created": "Thu, 24 Mar 2016 17:36:23 GMT", "version": "v3" }, { "created": "Sun, 16 Oct 2016 03:10:33 GMT", "version": "v4" } ]
2016-10-18
[ [ "Dias", "Marco", "" ], [ "Lee", "Cheng-Yang", "" ] ]
We study the loop corrections to the scalar propagator and the fermionic self-energy for the mass dimension one fermionic dark matter with the Yukawa interaction. We find, in the former case, there is a non-vanishing Lorentz-violating term while the later is Lorentz-invariant. Our study of the fermionic loop correction shows that unitarity demands the fermionic mass must be at least half of the bosonic mass and that the Lorentz-violating term makes a non-trivial correction to the bosonic propagator. We discuss what these results mean in the context of the Standard Model and the possibility of bypassing the unitarity constraint. In the simplest scenario, within the framework of standard quantum field theory, by identifying the scalar boson to be the Higgs boson with a mass of 125 GeV, the mass of the fermion must be at least 62.5 GeV.
hep-ph/9511219
null
E. Farhi, J. Goldstone, A. Lue and K. Rajagopal
Collision Induced Decays of Electroweak Solitons: Fermion Number Violation with Two and Few Initial Particles
64 pages, revtex, epsf, all figures included. Revised version. Section V replaced with a corrected version. Qualitative conclusions unchanged. Numerical value of one exponent has changed
Phys.Rev. D54 (1996) 5336-5360
10.1103/PhysRevD.54.5336
CTP-2483, HUTP-95-A039
hep-ph hep-th
null
We consider a variant of the standard electroweak theory in which the Higgs sector has been modified so that there is a classically stable weak scale soliton. We explore fermion number violating processes which involve soliton decay. A soliton can decay by tunnelling under the sphaleron barrier, or the decay can be collision induced if the energy is sufficient for the barrier to be traversed. We present a classical solution to the Minkowski space equations of motion in which a soliton is kicked over the barrier by an incoming pulse. This pulse corresponds to a quantum coherent state with mean number of $W$ quanta $\sim 2.5/g^2$ where $g$ is the $SU(2)$ gauge coupling constant. We also give a self-contained treatment of the relationship between classical solutions, including those in which solitons are destroyed, and tree-level quantum amplitudes. Furthermore, we consider a limit in which we can reliably estimate the amplitude for soliton decay induced by collision with a single $W$-boson. This amplitude depends on $g$ like $\exp (-cg^{-1/3})$, and is larger than that for spontaneous decay via tunnelling in the same limit. Finally we show that in soliton decays, light $SU(2)_L$ doublet fermions are anomalously produced. Thus we have a calculation of a two body process with energy above the sphaleron barrier in which fermion number is violated.
[ { "created": "Fri, 3 Nov 1995 00:14:11 GMT", "version": "v1" }, { "created": "Fri, 26 Jul 1996 23:39:23 GMT", "version": "v2" } ]
2009-10-28
[ [ "Farhi", "E.", "" ], [ "Goldstone", "J.", "" ], [ "Lue", "A.", "" ], [ "Rajagopal", "K.", "" ] ]
We consider a variant of the standard electroweak theory in which the Higgs sector has been modified so that there is a classically stable weak scale soliton. We explore fermion number violating processes which involve soliton decay. A soliton can decay by tunnelling under the sphaleron barrier, or the decay can be collision induced if the energy is sufficient for the barrier to be traversed. We present a classical solution to the Minkowski space equations of motion in which a soliton is kicked over the barrier by an incoming pulse. This pulse corresponds to a quantum coherent state with mean number of $W$ quanta $\sim 2.5/g^2$ where $g$ is the $SU(2)$ gauge coupling constant. We also give a self-contained treatment of the relationship between classical solutions, including those in which solitons are destroyed, and tree-level quantum amplitudes. Furthermore, we consider a limit in which we can reliably estimate the amplitude for soliton decay induced by collision with a single $W$-boson. This amplitude depends on $g$ like $\exp (-cg^{-1/3})$, and is larger than that for spontaneous decay via tunnelling in the same limit. Finally we show that in soliton decays, light $SU(2)_L$ doublet fermions are anomalously produced. Thus we have a calculation of a two body process with energy above the sphaleron barrier in which fermion number is violated.
1305.1313
Adam Martin
Graham D. Kribs, Adam Martin, Arjun Menon
Natural Supersymmetry and Implications for Higgs physics
18 pages, 8 figures
null
10.1103/PhysRevD.88.035025
CERN-PH-TH-2013-095
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We re-analyze the LHC bounds on light third generation squarks in Natural Supersymmetry, where the sparticles have masses inversely proportional to their leading-log contributions to the electroweak symmetry breaking scale. Higgsinos are the lightest supersymmetric particles; top and bottom squarks are the next-to-lightest sparticles that decay into both neutral and charged Higgsinos with well-defined branching ratios determined by Yukawa couplings and kinematics. The Higgsinos are nearly degenerate in mass, once the bino and wino masses are taken to their natural (heavy) values. We consider three scenarios for the stop and sbottom masses: (I) $\tilde{t}_R$ is light, (II) $\tilde{t}_L$ and $\tilde{b}_L$ are light, and (III) $\tilde{t}_R$, $\tilde{t}_L$, and $\tilde{b}_L$ are light. Dedicated stop searches are currently sensitive to Scenarios II and III, but not Scenario I. Sbottom-motivated searches ($2 b + \rm{MET}$) impact both squark flavors due to $\tilde{t} \ra b \charp_1$ as well as $\tilde{b} \ra b \neut_{1,2}$, constraining Scenarios I and III with somewhat weaker constraints on Scenario II. The totality of these searches yield relatively strong constraints on Natural Supersymmetry. Two regions that remain are: (1) the "compressed wedge", where $(m_{\tilde{q}} - |\mu|)/m_{\tilde{q}} \ll 1$, and (2) the "kinematic limit" region, where $m_{\tilde{q}} \gsim 600-750 GeV, at the kinematic limit of the LHC searches. We calculate the correlated predictions for Higgs physics, demonstrating that these regions lead to distinct predictions for the lightest Higgs couplings that are separable with $\simeq 10% measurements. We show that these conclusions remain largely unchanged once the MSSM is extended to the NMSSM in order to naturally obtain a large enough mass for the lightest Higgs boson consistent with LHC data.
[ { "created": "Mon, 6 May 2013 20:07:27 GMT", "version": "v1" } ]
2013-09-04
[ [ "Kribs", "Graham D.", "" ], [ "Martin", "Adam", "" ], [ "Menon", "Arjun", "" ] ]
We re-analyze the LHC bounds on light third generation squarks in Natural Supersymmetry, where the sparticles have masses inversely proportional to their leading-log contributions to the electroweak symmetry breaking scale. Higgsinos are the lightest supersymmetric particles; top and bottom squarks are the next-to-lightest sparticles that decay into both neutral and charged Higgsinos with well-defined branching ratios determined by Yukawa couplings and kinematics. The Higgsinos are nearly degenerate in mass, once the bino and wino masses are taken to their natural (heavy) values. We consider three scenarios for the stop and sbottom masses: (I) $\tilde{t}_R$ is light, (II) $\tilde{t}_L$ and $\tilde{b}_L$ are light, and (III) $\tilde{t}_R$, $\tilde{t}_L$, and $\tilde{b}_L$ are light. Dedicated stop searches are currently sensitive to Scenarios II and III, but not Scenario I. Sbottom-motivated searches ($2 b + \rm{MET}$) impact both squark flavors due to $\tilde{t} \ra b \charp_1$ as well as $\tilde{b} \ra b \neut_{1,2}$, constraining Scenarios I and III with somewhat weaker constraints on Scenario II. The totality of these searches yield relatively strong constraints on Natural Supersymmetry. Two regions that remain are: (1) the "compressed wedge", where $(m_{\tilde{q}} - |\mu|)/m_{\tilde{q}} \ll 1$, and (2) the "kinematic limit" region, where $m_{\tilde{q}} \gsim 600-750 GeV, at the kinematic limit of the LHC searches. We calculate the correlated predictions for Higgs physics, demonstrating that these regions lead to distinct predictions for the lightest Higgs couplings that are separable with $\simeq 10% measurements. We show that these conclusions remain largely unchanged once the MSSM is extended to the NMSSM in order to naturally obtain a large enough mass for the lightest Higgs boson consistent with LHC data.