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hep-ph/9305256
null
Boris Kopeliovich
Hadronization in Nuclear Matter
7 pages + 3 figs (available upon request), report# LPTHE 93-16
null
null
null
hep-ph
null
Nuclei are unique analyzers of the space-time development of jets at early stage. We argue that the gluon bremsstrahlung, rather than the color string, is the main mechanism of hadronization of highly virtual quarks produced in a hard interaction. It results in an energy- and time-independent density of energy loss, like a color string, but steeply dependent on the quark virtuality. Effects of formation zone (FZ) and color transparency (CT) substantially affect the jet quenching in a nuclear matter. The latter also plays an important role in the broadening of transverse momentum distribution of a quark passing a nucleus. Parameter-free calculations provide a good description of available data on nuclear effects in the leading hadron production in deep-inelastic lepton scattering, back-to-back high-$p_T$ hadron pair production, broadening of the transverse momentum distribution in the Drell-Yan process of lepton pair production on nuclei.
[ { "created": "Wed, 12 May 1993 17:08:12 GMT", "version": "v1" } ]
2007-05-23
[ [ "Kopeliovich", "Boris", "" ] ]
Nuclei are unique analyzers of the space-time development of jets at early stage. We argue that the gluon bremsstrahlung, rather than the color string, is the main mechanism of hadronization of highly virtual quarks produced in a hard interaction. It results in an energy- and time-independent density of energy loss, like a color string, but steeply dependent on the quark virtuality. Effects of formation zone (FZ) and color transparency (CT) substantially affect the jet quenching in a nuclear matter. The latter also plays an important role in the broadening of transverse momentum distribution of a quark passing a nucleus. Parameter-free calculations provide a good description of available data on nuclear effects in the leading hadron production in deep-inelastic lepton scattering, back-to-back high-$p_T$ hadron pair production, broadening of the transverse momentum distribution in the Drell-Yan process of lepton pair production on nuclei.
hep-ph/9309295
Francesco Sannino
Francesco Sannino
Violation Of The $\Delta I = 1/2$ Rule In $D \to \pi\pi$ Decays
Pages 13
Phys. Lett. B322 (1994) 259-262
10.1016/0370-2693(94)91117-7
SU-HEP-4240-551
hep-ph
null
A strong violation of the $\displaystyle{\Delta I = {1\over 2}} $ rule has experimentally been found in the $\displaystyle{D \to \pi\pi}$ decays [1]. In this letter we will show that the order of magnitude of this violation can be understood in terms of the pure quantum chromo dynamics corrections to the weak interactions.
[ { "created": "Mon, 20 Sep 1993 17:09:00 GMT", "version": "v1" } ]
2009-10-22
[ [ "Sannino", "Francesco", "" ] ]
A strong violation of the $\displaystyle{\Delta I = {1\over 2}} $ rule has experimentally been found in the $\displaystyle{D \to \pi\pi}$ decays [1]. In this letter we will show that the order of magnitude of this violation can be understood in terms of the pure quantum chromo dynamics corrections to the weak interactions.
1012.0824
Pedro David Ruiz-Femenia
M. Beneke, B. Jantzen and P. Ruiz-Femenia
Electroweak non-resonant corrections to top pair production close to threshold
Talk presented at the 35th International Conference of High Energy Physics - ICHEP2010, July 22-28, 2010, Paris France. 4 pages, 2 figures
null
10.22323/1.120.0076
TTK-10-53, SFB/CPP-10-124
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The production of W+ W- b bbar from e+ e- collisions at energies close to the t tbar threshold is dominated by the resonant process with a nearly on-shell t tbar intermediate state. The W b pairs in the final state can also be reached through the decay of off-shell tops or through background processes containing no or only single top quarks. This non-resonant production starts to contribute at NLO to the W+ W- b bbar total cross section in the non-relativistic power-counting v ~ alpha_s ~ sqrt(alpha_EW). The NLO non-resonant corrections presented in this talk represent the non-trivial NLO electroweak corrections to the e+ e- -> W+ W- b bbar cross section in the top anti-top resonance region. In contrast to the QCD corrections which have been calculated (almost) up to NNNLO, the parametrically larger NLO electroweak contributions have not been completely known so far, but are mandatory for the required accuracy at a future linear collider. We consider the total cross section of the e+ e- -> W+ W- b bbar process and additionally implement cuts on the invariant masses of the W+ b and W- bbar pairs.
[ { "created": "Fri, 3 Dec 2010 19:22:43 GMT", "version": "v1" } ]
2022-09-21
[ [ "Beneke", "M.", "" ], [ "Jantzen", "B.", "" ], [ "Ruiz-Femenia", "P.", "" ] ]
The production of W+ W- b bbar from e+ e- collisions at energies close to the t tbar threshold is dominated by the resonant process with a nearly on-shell t tbar intermediate state. The W b pairs in the final state can also be reached through the decay of off-shell tops or through background processes containing no or only single top quarks. This non-resonant production starts to contribute at NLO to the W+ W- b bbar total cross section in the non-relativistic power-counting v ~ alpha_s ~ sqrt(alpha_EW). The NLO non-resonant corrections presented in this talk represent the non-trivial NLO electroweak corrections to the e+ e- -> W+ W- b bbar cross section in the top anti-top resonance region. In contrast to the QCD corrections which have been calculated (almost) up to NNNLO, the parametrically larger NLO electroweak contributions have not been completely known so far, but are mandatory for the required accuracy at a future linear collider. We consider the total cross section of the e+ e- -> W+ W- b bbar process and additionally implement cuts on the invariant masses of the W+ b and W- bbar pairs.
1402.7360
Volodymyr Takhistov
Mu-Chun Chen and Volodymyr Takhistov
Charged Lepton Spectrum Approximation in a Three Body Nucleon Decay
4 pages, 2 figures
Phys. Rev. D 89, 095003 (2014)
10.1103/PhysRevD.89.095003
UCI-TR-2014-02
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Only phase space is typically used to obtain final state particle spectra in rare decay searches, which is a crude approximation in the case of three body processes. We will demonstrate how both dynamics and phase space can be approximately accounted for, in processes such as nucleon decays $p \rightarrow e^+ \bar{\nu} \nu$ or $p \rightarrow \mu^+ \bar{\nu} \nu$ originating from Grand Unification models, using general effective Fermi theory formalism of electroweak muon decay $\mu \rightarrow e^+ \bar{\nu} \nu$. This approach allows for a more precise and only weakly model dependent approximation of final particle spectra for these and similar decays, which may improve rare process searches in current and near-future experiments.
[ { "created": "Fri, 28 Feb 2014 20:04:35 GMT", "version": "v1" } ]
2014-05-14
[ [ "Chen", "Mu-Chun", "" ], [ "Takhistov", "Volodymyr", "" ] ]
Only phase space is typically used to obtain final state particle spectra in rare decay searches, which is a crude approximation in the case of three body processes. We will demonstrate how both dynamics and phase space can be approximately accounted for, in processes such as nucleon decays $p \rightarrow e^+ \bar{\nu} \nu$ or $p \rightarrow \mu^+ \bar{\nu} \nu$ originating from Grand Unification models, using general effective Fermi theory formalism of electroweak muon decay $\mu \rightarrow e^+ \bar{\nu} \nu$. This approach allows for a more precise and only weakly model dependent approximation of final particle spectra for these and similar decays, which may improve rare process searches in current and near-future experiments.
hep-ph/0111329
Bachir Moussallam
B. Moussallam (IPN, Orsay)
Virtual quarks, vacuum stability and scalar meson physics
7 pages, Talk given at " Chiral fluctuations in hadronic matter international workshop", Orsay, September 26-28, 2001
null
null
null
hep-ph
null
Results are reviewed, which provide relations between the response (and eventual instability) of the chiral QCD vacuum to an increase of the number of massless quarks in the theory and the observed violations of the large $N_c$ expansion in the scalar meson sector, by combining chiral perturbation theory expansions in $m_s$ with sum rule methods. An approach based on the construction of scalar form-factors was recently confirmed by an independent approach which uses the $\pi K$ scattering amplitudes.
[ { "created": "Mon, 26 Nov 2001 14:42:44 GMT", "version": "v1" } ]
2007-05-23
[ [ "Moussallam", "B.", "", "IPN, Orsay" ] ]
Results are reviewed, which provide relations between the response (and eventual instability) of the chiral QCD vacuum to an increase of the number of massless quarks in the theory and the observed violations of the large $N_c$ expansion in the scalar meson sector, by combining chiral perturbation theory expansions in $m_s$ with sum rule methods. An approach based on the construction of scalar form-factors was recently confirmed by an independent approach which uses the $\pi K$ scattering amplitudes.
hep-ph/0209295
Vladimir Smirnov
V.A. Smirnov
Evaluating double and triple (?) boxes
6 pages, LaTeX with axodraw.sty; Talk presented at the International Symposium Radcor 2002 and Loops and Legs 2002 (September 8--13, Kloster Banz, Germany); to appear in Nuclear Physics B (Proc. Suppl.); a wrong abstract is replaced
Nucl.Phys.Proc.Suppl. 116 (2003) 417-421
10.1016/S0920-5632(03)80211-6
null
hep-ph
null
A brief review of recent results on analytical evaluation of double-box Feynman integrals is presented. First steps towards evaluation of massless on-shell triple-box Feynman integrals within dimensional regularization are described. The leading power asymptotic behaviour of the dimensionally regularized massless on-shell master planar triple-box diagram in the Regge limit $t/s \to 0$ is evaluated. The evaluation of the unexpanded master planar triple box is outlined and explicit results for coefficients at $1/\ep^j$, j=2,...,6, are presented.
[ { "created": "Wed, 25 Sep 2002 11:42:10 GMT", "version": "v1" }, { "created": "Thu, 26 Sep 2002 06:20:49 GMT", "version": "v2" } ]
2009-11-07
[ [ "Smirnov", "V. A.", "" ] ]
A brief review of recent results on analytical evaluation of double-box Feynman integrals is presented. First steps towards evaluation of massless on-shell triple-box Feynman integrals within dimensional regularization are described. The leading power asymptotic behaviour of the dimensionally regularized massless on-shell master planar triple-box diagram in the Regge limit $t/s \to 0$ is evaluated. The evaluation of the unexpanded master planar triple box is outlined and explicit results for coefficients at $1/\ep^j$, j=2,...,6, are presented.
1405.0272
James Unwin
Adam Martin, Jessie Shelton, and James Unwin
Fitting the Galactic Center Gamma-Ray Excess with Cascade Annihilations
11 pages. v3: version to appear in PRD
Phys. Rev. D 90, 103513 (2014)
10.1103/PhysRevD.90.103513
null
hep-ph astro-ph.CO astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The apparent excess of gamma rays in an extended region in the direction of the galactic center has a spatial distribution and amplitude that are suggestive of dark matter annihilations. If this excess is indeed due to dark matter annihilations, it would indicate the presence of both dark matter and an additional particle beyond the Standard Model that mediates the interactions between the dark matter and Standard Model states. We introduce reference models describing dark matter annihilation to pairs of these new mediators, which decouples the SM-mediator coupling from the thermal annihilation cross section and easily explains the lack of direct detection signals. We determine the parameter regions that give good descriptions of the gamma ray excess for several motivated choices of mediator couplings to the SM. We find fermion dark matter with mass 7-26 GeV and a dark vector mediator, or scalar dark matter in the 10-50 GeV range (Higgs portal mediator) or 10-65 GeV range (gluophilic mediator) can provide a comparable or improved fit, compared to the case of direct annihilation. We demonstrate that these models can easily satisfy all constraints from collider experiments, direct detection, and cosmology.
[ { "created": "Thu, 1 May 2014 19:58:09 GMT", "version": "v1" }, { "created": "Wed, 21 May 2014 19:54:34 GMT", "version": "v2" }, { "created": "Mon, 20 Oct 2014 22:53:12 GMT", "version": "v3" } ]
2014-11-19
[ [ "Martin", "Adam", "" ], [ "Shelton", "Jessie", "" ], [ "Unwin", "James", "" ] ]
The apparent excess of gamma rays in an extended region in the direction of the galactic center has a spatial distribution and amplitude that are suggestive of dark matter annihilations. If this excess is indeed due to dark matter annihilations, it would indicate the presence of both dark matter and an additional particle beyond the Standard Model that mediates the interactions between the dark matter and Standard Model states. We introduce reference models describing dark matter annihilation to pairs of these new mediators, which decouples the SM-mediator coupling from the thermal annihilation cross section and easily explains the lack of direct detection signals. We determine the parameter regions that give good descriptions of the gamma ray excess for several motivated choices of mediator couplings to the SM. We find fermion dark matter with mass 7-26 GeV and a dark vector mediator, or scalar dark matter in the 10-50 GeV range (Higgs portal mediator) or 10-65 GeV range (gluophilic mediator) can provide a comparable or improved fit, compared to the case of direct annihilation. We demonstrate that these models can easily satisfy all constraints from collider experiments, direct detection, and cosmology.
1806.01714
Takaaki Nomura
Takaaki Nomura, Hiroshi Okada
An inverse seesaw model with $U(1)_R$ gauge symmetry
5 pages, 1 figure, version to be published in LHEP
null
null
KIAS-P18088, APCTP Pre2018-010
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose a natural realization of inverse seesaw model with right-handed and flavor dependent $U(1)$ gauge symmetries, in which we formulate the neutrino mass matrix to reproduce current neutrino oscillation data in a general way. Also we study a possibility to provide predictions to the neutrino sector by imposing an additional flavor dependent $U(1)_{L_\mu-L_\tau}$ gauge symmetry that also satisfies the gauge anomaly cancellation conditions associated with $U(1)_R$. Then we analyze collider physics on a extra gauge boson and show a possibility of detection.
[ { "created": "Tue, 5 Jun 2018 14:27:17 GMT", "version": "v1" }, { "created": "Mon, 20 Aug 2018 14:02:01 GMT", "version": "v2" } ]
2018-08-21
[ [ "Nomura", "Takaaki", "" ], [ "Okada", "Hiroshi", "" ] ]
We propose a natural realization of inverse seesaw model with right-handed and flavor dependent $U(1)$ gauge symmetries, in which we formulate the neutrino mass matrix to reproduce current neutrino oscillation data in a general way. Also we study a possibility to provide predictions to the neutrino sector by imposing an additional flavor dependent $U(1)_{L_\mu-L_\tau}$ gauge symmetry that also satisfies the gauge anomaly cancellation conditions associated with $U(1)_R$. Then we analyze collider physics on a extra gauge boson and show a possibility of detection.
1911.09438
Xin-Zhen Weng
Xin-Zhen Weng, Li-Ye Xiao, Wei-Zhen Deng, Xiao-Lin Chen, and Shi-Lin Zhu
Three body open flavor decays of higher vector charmonium and bottomonium
5 pages, 1 figure; contribution to the proceedings of the XVIII International Conference on Hadron Spectroscopy and Structure, HADRON-2019. August 16-21, Guilin, China
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
With an extended quark pair creation model we systematically study the OZI-allowed three body open flavor decays of higher vector charmonium and bottomonium states. We obtain that the $BB^*\pi$ and $B^*B^*\pi$ partial decay widths of $\Upsilon(10860)$ are consistent with experiment, and the corresponding partial decay widths of $\Upsilon(11020)$ can reach up to 2$\sim$3 MeV. Meanwhile the partial widths of $DD^*\pi$ and $D^*D^*\pi$ modes for most higher vector charmonium states can reach up to several MeV.
[ { "created": "Thu, 21 Nov 2019 12:31:20 GMT", "version": "v1" } ]
2019-11-22
[ [ "Weng", "Xin-Zhen", "" ], [ "Xiao", "Li-Ye", "" ], [ "Deng", "Wei-Zhen", "" ], [ "Chen", "Xiao-Lin", "" ], [ "Zhu", "Shi-Lin", "" ] ]
With an extended quark pair creation model we systematically study the OZI-allowed three body open flavor decays of higher vector charmonium and bottomonium states. We obtain that the $BB^*\pi$ and $B^*B^*\pi$ partial decay widths of $\Upsilon(10860)$ are consistent with experiment, and the corresponding partial decay widths of $\Upsilon(11020)$ can reach up to 2$\sim$3 MeV. Meanwhile the partial widths of $DD^*\pi$ and $D^*D^*\pi$ modes for most higher vector charmonium states can reach up to several MeV.
hep-ph/9603383
null
D. Apostolakis, P. Ditsas, and S. Katsanevas (Department of Physics, University of Crete and University of Athens)
The Standard Model process $e^+e^-\to \nu\bar{\nu}b\bar{b}$ and its Higgs signal at LEPI
18 pages + 12 compressed figures (use gunzip to decompress them)
Z.Phys. C76 (1997) 201-211
null
Crete 96-12
hep-ph
null
We present and study the results for the standard model process $e^+e^-\to \nu\bar{\nu}b\bar{b}$ at c.m energies 150$\leq \sqrt{s} (GeV) \leq $ 240 and for Higgs boson masses $80 GeV \leq m_H \leq 120 GeV$, obtained from all tree-level diagrams and including the most important radiative corrections. The $\sqrt{s}$ dependence and the interference properties of the Higgs boson contribution and of various coherent background contributions to the total cross section are examined. The effect of the QED initial state radiative corrections is estimated. The important differential distributions for the Higgs boson and the background components are studied, providing information usefull for choosing cuts in Higgs searches. We also examine the effect of a minimal set of cuts and evaluate the importance of the WW fusion for detecting a higher mass Higgs boson at LEPII.
[ { "created": "Fri, 22 Mar 1996 17:09:59 GMT", "version": "v1" }, { "created": "Mon, 25 Mar 1996 11:46:11 GMT", "version": "v2" } ]
2008-02-03
[ [ "Apostolakis", "D.", "", "Department of Physics,\n University of Crete and University of Athens" ], [ "Ditsas", "P.", "", "Department of Physics,\n University of Crete and University of Athens" ], [ "Katsanevas", "S.", "", "Department of Physics,\n University of Crete and University of Athens" ] ]
We present and study the results for the standard model process $e^+e^-\to \nu\bar{\nu}b\bar{b}$ at c.m energies 150$\leq \sqrt{s} (GeV) \leq $ 240 and for Higgs boson masses $80 GeV \leq m_H \leq 120 GeV$, obtained from all tree-level diagrams and including the most important radiative corrections. The $\sqrt{s}$ dependence and the interference properties of the Higgs boson contribution and of various coherent background contributions to the total cross section are examined. The effect of the QED initial state radiative corrections is estimated. The important differential distributions for the Higgs boson and the background components are studied, providing information usefull for choosing cuts in Higgs searches. We also examine the effect of a minimal set of cuts and evaluate the importance of the WW fusion for detecting a higher mass Higgs boson at LEPII.
hep-ph/9706295
Davor Palle
D. Palle (Rugjer Boskovic Institute, Zagreb, Croatia)
A new contribution to the flavour-changing lepton- photon vertex
7 pages, LaTeX style; IL NUOVO CIMENTO A (1997) in press
Nuovo Cim. A110 (1997) 143-147; Erratum-ibid. A110 (1997) 457
10.1007/BF03185553
null
hep-ph
null
We show that the correct perturbation theory for mixed fermion states leads to nonvanishing contributions of the dimension-four vertex operators for flavour-changing transitions. Their contributions to the amplitude are of the same order of magnitude as the dimension- five vertex operators. Considerations are valid irrespective of the electroweak model. A complete and correct evaluation of the neutrino lifetime for particular electroweak models could be of greate importance in the theoretical cosmology and astrophysics.
[ { "created": "Mon, 9 Jun 1997 14:26:23 GMT", "version": "v1" } ]
2022-03-02
[ [ "Palle", "D.", "", "Rugjer Boskovic Institute, Zagreb, Croatia" ] ]
We show that the correct perturbation theory for mixed fermion states leads to nonvanishing contributions of the dimension-four vertex operators for flavour-changing transitions. Their contributions to the amplitude are of the same order of magnitude as the dimension- five vertex operators. Considerations are valid irrespective of the electroweak model. A complete and correct evaluation of the neutrino lifetime for particular electroweak models could be of greate importance in the theoretical cosmology and astrophysics.
1609.00860
Fagner Correia
F. C. Correia, Svjetlana Fajfer
Restrained Dark $U(1)_d$ at Low Energies
13 pages, 10 figures
Phys. Rev. D 94, 115023 (2016)
10.1103/PhysRevD.94.115023
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate a spontaneously broken $U(1)_d$ gauge symmetry with a muon-specific dark Higgs. Our first goal is to verify how the presence of a new dark Higgs, $\phi$, and a dark gauge boson, $V$, can simultaneously face the anomalies from the muon magnetic moment and the proton charge radius. Secondly, by assuming that $V$ must decay to an electron-positron pair, we explore the corresponding parameter space determined with the low energy constraints coming from $ K \to \mu X$, electron $(g-2)_e$, $K \to \mu \nu_\mu e^+ e^-$, $K \to \mu \nu_\mu \mu^+ \mu^-$, $\tau \to \nu_\tau \mu \nu_\mu e^+ e^-$. We focus in the scenario where the $V$ mass is below $ \sim 2 m_\mu$ and the $\phi$ mass runs from few MeV till $250$ MeV, with V-photon mixing of the order $ \sim\mathcal{O}(10^{-3})$. Among weak process at low energies, we check the influence of the new light vector on kaon decays as well as on the scattering $e^+ e^- \rightarrow \mu^+ \mu^- e^+ e^-$ and discuss the impact of the dark Higgs on $e^+ e^- \rightarrow \mu^+ \mu^- \mu^+ \mu^- $. Finally, we consider contributions of the V-photon mixing in the decays $\pi^0 \to \gamma e^+ e^-$, $\eta \to \gamma e^+ e^-$, $\rho \to \pi e^+ e^-$, $K^* \to K e^+ e^-$ and $\phi (1020) \to \eta e^+ e^-$.
[ { "created": "Sat, 3 Sep 2016 20:30:44 GMT", "version": "v1" } ]
2016-12-28
[ [ "Correia", "F. C.", "" ], [ "Fajfer", "Svjetlana", "" ] ]
We investigate a spontaneously broken $U(1)_d$ gauge symmetry with a muon-specific dark Higgs. Our first goal is to verify how the presence of a new dark Higgs, $\phi$, and a dark gauge boson, $V$, can simultaneously face the anomalies from the muon magnetic moment and the proton charge radius. Secondly, by assuming that $V$ must decay to an electron-positron pair, we explore the corresponding parameter space determined with the low energy constraints coming from $ K \to \mu X$, electron $(g-2)_e$, $K \to \mu \nu_\mu e^+ e^-$, $K \to \mu \nu_\mu \mu^+ \mu^-$, $\tau \to \nu_\tau \mu \nu_\mu e^+ e^-$. We focus in the scenario where the $V$ mass is below $ \sim 2 m_\mu$ and the $\phi$ mass runs from few MeV till $250$ MeV, with V-photon mixing of the order $ \sim\mathcal{O}(10^{-3})$. Among weak process at low energies, we check the influence of the new light vector on kaon decays as well as on the scattering $e^+ e^- \rightarrow \mu^+ \mu^- e^+ e^-$ and discuss the impact of the dark Higgs on $e^+ e^- \rightarrow \mu^+ \mu^- \mu^+ \mu^- $. Finally, we consider contributions of the V-photon mixing in the decays $\pi^0 \to \gamma e^+ e^-$, $\eta \to \gamma e^+ e^-$, $\rho \to \pi e^+ e^-$, $K^* \to K e^+ e^-$ and $\phi (1020) \to \eta e^+ e^-$.
hep-ph/0212319
Kalmykov Mikhail
F.Jegerlehner (DESY, Zeuthen), M.Yu.Kalmykov (DESY, Zeuthen & Dubna, JINR), O.Veretin (Karlsruhe U., ITT)
MS Versus Pole Masses of Gauge Bosons II: Two-Loop Electroweak Fermion Corrections
62 pages, LaTeX, 18 eps-figures, version to appear in Nucl.Phys.B
Nucl.Phys. B658 (2003) 49-112
10.1016/S0550-3213(03)00177-9
DESY-02-156
hep-ph
null
We have calculated the fermion contributions to the shift of the position of the poles of the massive gauge boson propagators at two-loop order in the Standard Model. Together with the bosonic contributions calculated previously the full two-loop corrections are available. This allows us to investigate the full correction in the relationship between MS and pole masses of the vector bosons Z and W. Two-loop renormalization and the corresponding renormalization group equations are discussed. Analytical results for the master-integrals appearing in the massless fermion contributions are given. A new approach of summing multiple binomial sums has been developed.
[ { "created": "Fri, 20 Dec 2002 19:18:58 GMT", "version": "v1" }, { "created": "Tue, 25 Feb 2003 19:47:00 GMT", "version": "v2" } ]
2009-11-07
[ [ "Jegerlehner", "F.", "", "DESY, Zeuthen" ], [ "Kalmykov", "M. Yu.", "", "DESY, Zeuthen & Dubna,\n JINR" ], [ "Veretin", "O.", "", "Karlsruhe U., ITT" ] ]
We have calculated the fermion contributions to the shift of the position of the poles of the massive gauge boson propagators at two-loop order in the Standard Model. Together with the bosonic contributions calculated previously the full two-loop corrections are available. This allows us to investigate the full correction in the relationship between MS and pole masses of the vector bosons Z and W. Two-loop renormalization and the corresponding renormalization group equations are discussed. Analytical results for the master-integrals appearing in the massless fermion contributions are given. A new approach of summing multiple binomial sums has been developed.
1405.0495
Christopher McCabe
Jonathan H. Davis, Christopher McCabe and Celine Boehm
Quantifying the evidence for Dark Matter in CoGeNT data
26 pages, 17 figures. v1: Typeset with REVTeX. v2: Minor changes to the text to match the published version. Typeset with JCAP style
null
10.1088/1475-7516/2014/08/014
IPPP/14/32, DCPT/14/64
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We perform an independent analysis of data from the CoGeNT direct detection experiment to quantify the evidence for dark matter recoils. We critically re-examine the assumptions that enter the analysis, focusing specifically on the separation of bulk and surface events, the latter of which constitute a large background. This separation is performed using the event rise-time, with the surface events being slower on average. We fit the rise-time distributions for the bulk and surface events with a log-normal and Pareto distribution (which gives a better fit to the tail in the bulk population at high rise-times) and account for the energy-dependence of the bulk fraction using a cubic spline. Using Bayesian and frequentist techniques and additionally investigating the effect of varying the rise-time cut, the bulk background spectrum and bin-sizes, we conclude that the CoGeNT data show a preference for light dark matter recoils at less than 1 sigma.
[ { "created": "Fri, 2 May 2014 20:01:02 GMT", "version": "v1" }, { "created": "Wed, 6 Aug 2014 20:02:40 GMT", "version": "v2" } ]
2014-08-08
[ [ "Davis", "Jonathan H.", "" ], [ "McCabe", "Christopher", "" ], [ "Boehm", "Celine", "" ] ]
We perform an independent analysis of data from the CoGeNT direct detection experiment to quantify the evidence for dark matter recoils. We critically re-examine the assumptions that enter the analysis, focusing specifically on the separation of bulk and surface events, the latter of which constitute a large background. This separation is performed using the event rise-time, with the surface events being slower on average. We fit the rise-time distributions for the bulk and surface events with a log-normal and Pareto distribution (which gives a better fit to the tail in the bulk population at high rise-times) and account for the energy-dependence of the bulk fraction using a cubic spline. Using Bayesian and frequentist techniques and additionally investigating the effect of varying the rise-time cut, the bulk background spectrum and bin-sizes, we conclude that the CoGeNT data show a preference for light dark matter recoils at less than 1 sigma.
1411.0259
Nathan Hartland
Nathan Hartland
Proton structure at the LHC
231 pages, PhD Thesis
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A determination of Parton Distribution Functions (PDFs) from a global fit to a dataset including measurements from the LHC has been performed. The determinations have been carried out according to the NNPDF methodology, leading to a fit minimising parametrisation bias and with an accurate account of PDF uncertainty. In this thesis the importance of QCD measurements at the LHC to PDF extraction are discussed, and we summarise some of the technical difficulties in their inclusion into PDF fits. A number of methods are presented that permit the efficient inclusion of these observables into PDF determinations. Firstly a Bayesian reweighting procedure taking advantage of the Monte Carlo representation of PDF uncertainties in NNPDF sets is discussed, which is demonstrated by a study of the impact of early W production asymmetry measurements from ATLAS, CMS and LHCb upon an earlier PDF set. A package for the fast computation of observables in an automated NLO framework is presented, providing an interface between Monte Carlo event generators and NLO interpolation tools. Finally, a method of combining PDF evolution with interpolating codes for hadronic observable computation is described. This method largely overcomes the computational difficulties in performing fast perturbative QCD predictions for collider observables. The method has been applied to the determination of PDFs from a global dataset including vector boson production data from LHCb, ATLAS and CMS along with inclusive jet data from ATLAS. Finally, the method of closure testing is introduced, and the method is applied to the study of the NNPDF methodology. A number of improvements are found in the minimisation and stopping procedures, which are adopted for the development of the next NNPDF release, NNPDF3.0.
[ { "created": "Sun, 2 Nov 2014 14:22:50 GMT", "version": "v1" } ]
2014-11-04
[ [ "Hartland", "Nathan", "" ] ]
A determination of Parton Distribution Functions (PDFs) from a global fit to a dataset including measurements from the LHC has been performed. The determinations have been carried out according to the NNPDF methodology, leading to a fit minimising parametrisation bias and with an accurate account of PDF uncertainty. In this thesis the importance of QCD measurements at the LHC to PDF extraction are discussed, and we summarise some of the technical difficulties in their inclusion into PDF fits. A number of methods are presented that permit the efficient inclusion of these observables into PDF determinations. Firstly a Bayesian reweighting procedure taking advantage of the Monte Carlo representation of PDF uncertainties in NNPDF sets is discussed, which is demonstrated by a study of the impact of early W production asymmetry measurements from ATLAS, CMS and LHCb upon an earlier PDF set. A package for the fast computation of observables in an automated NLO framework is presented, providing an interface between Monte Carlo event generators and NLO interpolation tools. Finally, a method of combining PDF evolution with interpolating codes for hadronic observable computation is described. This method largely overcomes the computational difficulties in performing fast perturbative QCD predictions for collider observables. The method has been applied to the determination of PDFs from a global dataset including vector boson production data from LHCb, ATLAS and CMS along with inclusive jet data from ATLAS. Finally, the method of closure testing is introduced, and the method is applied to the study of the NNPDF methodology. A number of improvements are found in the minimisation and stopping procedures, which are adopted for the development of the next NNPDF release, NNPDF3.0.
1508.07962
Giovanni Antonio Chirilli
Giovanni A. Chirilli, Yuri V. Kovchegov, Douglas E. Wertepny
Regularization of the Light-Cone Gauge Gluon Propagator Singularities Using Sub-Gauge Conditions
19 pages, 2 figures
null
10.1007/JHEP12(2015)138
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Perturbative QCD calculations in the light-cone gauge have long suffered from the ambiguity associated with the regularization of the poles in the gluon propagator. In this work we study sub-gauge conditions within the light-cone gauge corresponding to several known ways of regulating the gluon propagator. Using the functional integral calculation of the gluon propagator, we rederive the known sub-gauge conditions for the theta-function gauges and identify the sub-gauge condition for the principal value (PV) regularization of the gluon propagator's light-cone poles. The obtained sub-gauge condition for the PV case is further verified by a sample calculation of the classical Yang-Mills field of two collinear ultrarelativistic point color charges. Our method does not allow one to construct a sub-gauge condition corresponding to the well-known Mandelstam-Leibbrandt prescription for regulating the gluon propagator poles.
[ { "created": "Mon, 31 Aug 2015 19:00:26 GMT", "version": "v1" } ]
2016-01-27
[ [ "Chirilli", "Giovanni A.", "" ], [ "Kovchegov", "Yuri V.", "" ], [ "Wertepny", "Douglas E.", "" ] ]
Perturbative QCD calculations in the light-cone gauge have long suffered from the ambiguity associated with the regularization of the poles in the gluon propagator. In this work we study sub-gauge conditions within the light-cone gauge corresponding to several known ways of regulating the gluon propagator. Using the functional integral calculation of the gluon propagator, we rederive the known sub-gauge conditions for the theta-function gauges and identify the sub-gauge condition for the principal value (PV) regularization of the gluon propagator's light-cone poles. The obtained sub-gauge condition for the PV case is further verified by a sample calculation of the classical Yang-Mills field of two collinear ultrarelativistic point color charges. Our method does not allow one to construct a sub-gauge condition corresponding to the well-known Mandelstam-Leibbrandt prescription for regulating the gluon propagator poles.
hep-ph/9511251
Dandi Wu
Dan-di Wu
Small Elements in Fermion Mass Matrices and Anomalous Dipole Moments
18 pages, 2 tabs, 2 figs. Reworded, to appear in Physics Letters B
Phys.Lett. B374 (1996) 100-110
10.1016/0370-2693(96)00121-9
Prairie View A&M, HEP-8-95
hep-ph
null
Assuming the small entries in the mass matrices are produced by fermion-scalar loops, we calculate the anomalous dipole moments of the leptons and quarks. The top quark appears in all the loops as the mass seed. When comparing the results with experimental data, including electric and magnetic dipole moments, and radiative transition rates, we obtain the mass limits which are typically larger than .1 TeV for the relevant neutral scalars, and 70 TeV for the relevant lepto-quarks. We then discuss the $P-\bar P$ mixing with a toy model. Rates of the known mixings require the masses of some neutral scalars to be large.
[ { "created": "Mon, 6 Nov 1995 18:44:13 GMT", "version": "v1" }, { "created": "Thu, 18 Jan 1996 23:12:13 GMT", "version": "v2" }, { "created": "Fri, 19 Jan 1996 16:55:20 GMT", "version": "v3" } ]
2015-06-25
[ [ "Wu", "Dan-di", "" ] ]
Assuming the small entries in the mass matrices are produced by fermion-scalar loops, we calculate the anomalous dipole moments of the leptons and quarks. The top quark appears in all the loops as the mass seed. When comparing the results with experimental data, including electric and magnetic dipole moments, and radiative transition rates, we obtain the mass limits which are typically larger than .1 TeV for the relevant neutral scalars, and 70 TeV for the relevant lepto-quarks. We then discuss the $P-\bar P$ mixing with a toy model. Rates of the known mixings require the masses of some neutral scalars to be large.
1208.6012
Arman Esmaili
Arman Esmaili and Yasaman Farzan
Implications of the Pseudo-Dirac Scenario for Ultra High Energy Neutrinos from GRBs
14 pages, 5 figures; v2: figures added, discussion improved, matches the version published in JCAP
JCAP 1212 (2012) 014
10.1088/1475-7516/2012/12/014
null
hep-ph astro-ph.CO astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The source of Ultra High Energy Cosmic Rays (UHECR) is still an unresolved mystery. Up until recently, sources of Gamma Ray Bursts (GRBs) had been considered as a suitable source for UHECR. Within the fireball model, the UHECR produced at GRBs should be accompanied with a neutrino flux detectable at the neutrino telescope such as IceCube. Recently, IceCube has set an upper bound on the neutrino flux accompanied by GRBs about 3.7 times below the prediction. We investigate whether this deficit can be explained by the oscillation of the active neutrinos to sterile neutrinos en route from the source to the detectors within the pseudo-Dirac scenario. We then discuss the implication of this scenario for diffuse supernova relic neutrinos.
[ { "created": "Wed, 29 Aug 2012 20:01:16 GMT", "version": "v1" }, { "created": "Thu, 7 Mar 2013 21:05:12 GMT", "version": "v2" } ]
2015-06-11
[ [ "Esmaili", "Arman", "" ], [ "Farzan", "Yasaman", "" ] ]
The source of Ultra High Energy Cosmic Rays (UHECR) is still an unresolved mystery. Up until recently, sources of Gamma Ray Bursts (GRBs) had been considered as a suitable source for UHECR. Within the fireball model, the UHECR produced at GRBs should be accompanied with a neutrino flux detectable at the neutrino telescope such as IceCube. Recently, IceCube has set an upper bound on the neutrino flux accompanied by GRBs about 3.7 times below the prediction. We investigate whether this deficit can be explained by the oscillation of the active neutrinos to sterile neutrinos en route from the source to the detectors within the pseudo-Dirac scenario. We then discuss the implication of this scenario for diffuse supernova relic neutrinos.
hep-ph/0212213
Mingzhe Li
Bo Feng and Mingzhe Li
Curvaton Reheating in Non-oscillatory Inflationary Models
4 pages, 1 figure
Phys.Lett. B564 (2003) 169-174
10.1016/S0370-2693(03)00589-6
BIHEP-TH-2002-57
hep-ph astro-ph
null
In non-oscillatory (NO) inflationary models, the reheating mechanism was usually based on gravitational particle production or the mechanism of instant preheating. In this paper we introduce the curvaton mechanism into NO models to reheat the universe and generate the curvature perturbation. Specifically we consider the Peebles-Vilenkin quintessential inflation model, where the reheating temperature can be extended from 1MeV to $10^{13}$GeV.
[ { "created": "Sun, 15 Dec 2002 21:39:36 GMT", "version": "v1" }, { "created": "Thu, 26 Jun 2003 06:29:46 GMT", "version": "v2" } ]
2009-11-07
[ [ "Feng", "Bo", "" ], [ "Li", "Mingzhe", "" ] ]
In non-oscillatory (NO) inflationary models, the reheating mechanism was usually based on gravitational particle production or the mechanism of instant preheating. In this paper we introduce the curvaton mechanism into NO models to reheat the universe and generate the curvature perturbation. Specifically we consider the Peebles-Vilenkin quintessential inflation model, where the reheating temperature can be extended from 1MeV to $10^{13}$GeV.
hep-ph/9602292
Jan Kalinowski
Jan Kalinowski, Maria Krawczyk (Warsaw Univ.)
Two-Higgs-doublet models and the Yukawa process at LEP1
9 pages, Latex, 2 figures in uuencoded Postscript format, for correspondence: kalino@fuw.edu.pl, krawczyk@fuw.edu.pl
Acta Phys.Polon. B27 (1996) 961-970
null
IFT 96-03
hep-ph
null
We investigate the production of Higgs bosons $A/h$ via the Yukawa process $Z\ra f\bar{f} \ra f\bar{f} A/h $ taking into account QCD corrections and fermion mass effects. We estimate the discovery reach of this process and/or bounds on the parameter space of two-Higgs doublet models which can be derived from the analysis of $b {\bar b} \tau^+ \tau^-$ events at LEP1. These limits have important consequences for extended models of electroweak interactions and their experimental verification/improvement are welcome.
[ { "created": "Tue, 13 Feb 1996 15:15:58 GMT", "version": "v1" } ]
2007-05-23
[ [ "Kalinowski", "Jan", "", "Warsaw Univ." ], [ "Krawczyk", "Maria", "", "Warsaw Univ." ] ]
We investigate the production of Higgs bosons $A/h$ via the Yukawa process $Z\ra f\bar{f} \ra f\bar{f} A/h $ taking into account QCD corrections and fermion mass effects. We estimate the discovery reach of this process and/or bounds on the parameter space of two-Higgs doublet models which can be derived from the analysis of $b {\bar b} \tau^+ \tau^-$ events at LEP1. These limits have important consequences for extended models of electroweak interactions and their experimental verification/improvement are welcome.
1912.08156
Petja Paakkinen
Petja Paakkinen
New constraints for nuclear parton distribution functions from hadron-nucleus collision processes
PhD thesis, introductory part
JYU Dissertations 115, 2019, ISBN:978-951-39-7828-0, ISSN 2489-9003
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This work studies collinearly factorizable nuclear parton distribution functions (nPDFs) in perturbative Quantum Chromodynamics (QCD) at next-to-leading order in the light of hadron-nucleus collision data which have not been included in nPDF analyses previously. The aim is at setting new constraints on the nuclear modifications of the gluon distribution and on the flavour separation of quark nuclear modifications. The introductory part provides an outline of the theoretical framework of QCD collinear factorization and the used statistical methods and relates the work presented here to other similar contemporary analyses. As a result, a new set of nPDFs, EPPS16, is presented, including for the first time electroweak-boson and dijet production data from CERN-LHC proton-lead collisions and allowing a full flavour separation in the fit. The flavour separation is constrained with Drell-Yan dilepton-production data from fixed target pion-nucleus experiments and neutrino-nucleus deep-inelastic scattering data, which are shown to give evidence for the similarity of the u and d valence-quark nuclear modifications. For studying the gluon degrees of freedom, collider data are essential and in the EPPS16 analysis new constraints are derived from the dijet production at the LHC. Possible further constraints for the gluons are investigated in terms of the LHC data on nuclear modification ratios of dijet and D-meson production. Using a non-quadratically improved Hessian reweighting method, these measurements are found to put stringent constraints on the gluon modifications in the lead nucleus, reaching smaller values of the nucleon momentum fraction than previously accessible. A study on the future prospects of constraining nPDFs within a multi-observable approach with the BNL-RHIC is also given.
[ { "created": "Tue, 17 Dec 2019 17:50:23 GMT", "version": "v1" } ]
2019-12-18
[ [ "Paakkinen", "Petja", "" ] ]
This work studies collinearly factorizable nuclear parton distribution functions (nPDFs) in perturbative Quantum Chromodynamics (QCD) at next-to-leading order in the light of hadron-nucleus collision data which have not been included in nPDF analyses previously. The aim is at setting new constraints on the nuclear modifications of the gluon distribution and on the flavour separation of quark nuclear modifications. The introductory part provides an outline of the theoretical framework of QCD collinear factorization and the used statistical methods and relates the work presented here to other similar contemporary analyses. As a result, a new set of nPDFs, EPPS16, is presented, including for the first time electroweak-boson and dijet production data from CERN-LHC proton-lead collisions and allowing a full flavour separation in the fit. The flavour separation is constrained with Drell-Yan dilepton-production data from fixed target pion-nucleus experiments and neutrino-nucleus deep-inelastic scattering data, which are shown to give evidence for the similarity of the u and d valence-quark nuclear modifications. For studying the gluon degrees of freedom, collider data are essential and in the EPPS16 analysis new constraints are derived from the dijet production at the LHC. Possible further constraints for the gluons are investigated in terms of the LHC data on nuclear modification ratios of dijet and D-meson production. Using a non-quadratically improved Hessian reweighting method, these measurements are found to put stringent constraints on the gluon modifications in the lead nucleus, reaching smaller values of the nucleon momentum fraction than previously accessible. A study on the future prospects of constraining nPDFs within a multi-observable approach with the BNL-RHIC is also given.
0804.4506
Chitta Ranjan Das
C.D. Froggatt, L.V. Laperashvili, R.B Nevzorov, H.B. Nielsen and C.R. Das
New Bound States of Top-anti-Top Quarks and T-balls Production at Colliders (Tevatron, LHC, etc.)
43 pages, 20 figures
null
null
CHEP-PKU-1-04-2008
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The present talk is based on the assumption that New Bound States (NBSs) of top-anti-top quarks (named T-balls) exist in the Standard Model (SM): a) there exists the scalar 1S - bound state of 6t+6\bar t - the bound state of 6 top-quarks with their 6 anti-top-quarks; b) the forces which bind these top-quarks are very strong and almost completely compensate the mass of the 12 top-anti-top-quarks forming this bound state; c) such strong forces are produced by the interactions of top-quarks via the virtual exchange of the scalar Higgs bosons having the large value of the top-quark Yukawa coupling constant g_t\simeq 1. Theory also predicts the existence of the NBS 6t + 5\bar t, which is a color triplet and a fermion similar to the t'-quark of the fourth generation. We have also considered "b-replaced" NBSs: n_b b + (6t + 6\bar t - n_b t) and n'_b b + (6t + 5\bar t - n'_b t), etc. We have estimated the masses of the lightest "b-replaced" NBS: M_{NBS}\simeq (300 - 400) GeV, and discussed the larger masses of the NBSs. We have developed a theory of the scalar T-ball's condensate, and predicted the existence of the three SM phases, calculating the top-quark Yukawa coupling constant at the border of two phases (with T-ball's condensate and without it) equal to: g_t \approx 1. The searching for the Higgs boson H and T-balls at the Tevatron and LHC is discussed.
[ { "created": "Mon, 28 Apr 2008 23:41:38 GMT", "version": "v1" }, { "created": "Thu, 26 Feb 2009 12:00:16 GMT", "version": "v2" } ]
2009-02-26
[ [ "Froggatt", "C. D.", "" ], [ "Laperashvili", "L. V.", "" ], [ "Nevzorov", "R. B", "" ], [ "Nielsen", "H. B.", "" ], [ "Das", "C. R.", "" ] ]
The present talk is based on the assumption that New Bound States (NBSs) of top-anti-top quarks (named T-balls) exist in the Standard Model (SM): a) there exists the scalar 1S - bound state of 6t+6\bar t - the bound state of 6 top-quarks with their 6 anti-top-quarks; b) the forces which bind these top-quarks are very strong and almost completely compensate the mass of the 12 top-anti-top-quarks forming this bound state; c) such strong forces are produced by the interactions of top-quarks via the virtual exchange of the scalar Higgs bosons having the large value of the top-quark Yukawa coupling constant g_t\simeq 1. Theory also predicts the existence of the NBS 6t + 5\bar t, which is a color triplet and a fermion similar to the t'-quark of the fourth generation. We have also considered "b-replaced" NBSs: n_b b + (6t + 6\bar t - n_b t) and n'_b b + (6t + 5\bar t - n'_b t), etc. We have estimated the masses of the lightest "b-replaced" NBS: M_{NBS}\simeq (300 - 400) GeV, and discussed the larger masses of the NBSs. We have developed a theory of the scalar T-ball's condensate, and predicted the existence of the three SM phases, calculating the top-quark Yukawa coupling constant at the border of two phases (with T-ball's condensate and without it) equal to: g_t \approx 1. The searching for the Higgs boson H and T-balls at the Tevatron and LHC is discussed.
1003.3410
Ernest Ma
Ernest Ma (UC Riverside)
Unifiable Supersymmetric Dark Left-Right Gauge Model
9 pages, no figure
Phys.Rev.D81:117703,2010
10.1103/PhysRevD.81.117703
UCRHEP-T488 (March 2010)
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The recently proposed dark left-right gauge model, with Z' and W_R bosons at the TeV scale, is shown to have a simple supersymmetric extension which is unifiable. Its one-loop gauge-coupling renormalization-group equations are shown to have identical solutions to those of the minimal supersymmetric standard model. It also has a rich dark sector, with at least three stable particles.
[ { "created": "Wed, 17 Mar 2010 17:13:00 GMT", "version": "v1" } ]
2011-11-23
[ [ "Ma", "Ernest", "", "UC Riverside" ] ]
The recently proposed dark left-right gauge model, with Z' and W_R bosons at the TeV scale, is shown to have a simple supersymmetric extension which is unifiable. Its one-loop gauge-coupling renormalization-group equations are shown to have identical solutions to those of the minimal supersymmetric standard model. It also has a rich dark sector, with at least three stable particles.
hep-ph/0608159
Kirill Tuchin
Kirill Tuchin
Pair production by boost-invariant fields in comoving coordinates
12 pages, 2 figures. Discussion added and typos fixed
J.Phys.G34:2633-2642,2007
10.1088/0954-3899/34/12/008
RBRC-688
hep-ph
null
We derive the pair-production probability in a constant electric field in Rindler coordinates in a quasi-classical approximation. Our result is different from the pair-production probability in an inertial frame (Schwinger formula). In particular, it exhibits non-trivial dependence on rapidity and deviation from Gaussian behavior at small transverse momenta. Our results can be important for analysis of particle production in heavy-ion collisions.
[ { "created": "Mon, 14 Aug 2006 18:11:01 GMT", "version": "v1" }, { "created": "Mon, 1 Oct 2007 14:48:40 GMT", "version": "v2" } ]
2008-11-26
[ [ "Tuchin", "Kirill", "" ] ]
We derive the pair-production probability in a constant electric field in Rindler coordinates in a quasi-classical approximation. Our result is different from the pair-production probability in an inertial frame (Schwinger formula). In particular, it exhibits non-trivial dependence on rapidity and deviation from Gaussian behavior at small transverse momenta. Our results can be important for analysis of particle production in heavy-ion collisions.
1408.2534
Joao Silva
Duarte Fontes, J. C. Rom\~ao, Jo\~ao P. Silva
$h \rightarrow Z \gamma$ in the complex two Higgs doublet model
31 pages, 15 figures
null
10.1007/JHEP12(2014)043
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The latest LHC data confirmed the existence of a Higgs-like particle and made interesting measurements on its decays into $\gamma \gamma$, $Z Z^\ast$, $W W^\ast$, $\tau^+ \tau^-$, and $b \bar{b}$. It is expected that a decay into $Z \gamma$ might be measured at the next LHC round, for which there already exists an upper bound. The Higgs-like particle could be a mixture of scalar with a relatively large component of pseudoscalar. We compute the decay of such a mixed state into $Z \gamma$, and we study its properties in the context of the complex two Higgs doublet model, analysing the effect of the current measurements on the four versions of this model. We show that a measurement of the $h \rightarrow Z \gamma$ rate at a level consistent with the SM can be used to place interesting constraints on the pseudoscalar component. We also comment on the issue of a wrong sign Yukawa coupling for the bottom in Type II models.
[ { "created": "Mon, 11 Aug 2014 20:03:37 GMT", "version": "v1" } ]
2015-06-22
[ [ "Fontes", "Duarte", "" ], [ "Romão", "J. C.", "" ], [ "Silva", "João P.", "" ] ]
The latest LHC data confirmed the existence of a Higgs-like particle and made interesting measurements on its decays into $\gamma \gamma$, $Z Z^\ast$, $W W^\ast$, $\tau^+ \tau^-$, and $b \bar{b}$. It is expected that a decay into $Z \gamma$ might be measured at the next LHC round, for which there already exists an upper bound. The Higgs-like particle could be a mixture of scalar with a relatively large component of pseudoscalar. We compute the decay of such a mixed state into $Z \gamma$, and we study its properties in the context of the complex two Higgs doublet model, analysing the effect of the current measurements on the four versions of this model. We show that a measurement of the $h \rightarrow Z \gamma$ rate at a level consistent with the SM can be used to place interesting constraints on the pseudoscalar component. We also comment on the issue of a wrong sign Yukawa coupling for the bottom in Type II models.
0801.0872
Alexander S. Sakharov
Nick E. Mavromatos, Anselmo Meregaglia, Andre Rubbia, Alexander Sakharov and Sarben Sarkar
Quantum-Gravity Decoherence Effects in Neutrino Oscillations: Expected Constraints from CNGS and J-PARC
40 pages, 8 figures, minor corrections
Phys.Rev.D77:053014,2008
10.1103/PhysRevD.77.053014
CERN-TH-PH/2007-267
hep-ph gr-qc hep-th
null
Quantum decoherence, the evolution of pure states into mixed states, may be a feature of quantum-gravity models. In most cases, such models lead to fewer neutrinos of all active flavours being detected in a long baseline experiment as compared to three-flavour standard neutrino oscillations. We discuss the potential of the CNGS and J-PARC beams in constraining models of quantum-gravity induced decoherence using neutrino oscillations as a probe. We use as much as possible model-independent parameterizations, even though they are motivated by specific microscopic models, for fits to the expected experimental data which yield bounds on quantum-gravity decoherence parameters.
[ { "created": "Sun, 6 Jan 2008 16:17:52 GMT", "version": "v1" }, { "created": "Fri, 11 Jan 2008 19:33:22 GMT", "version": "v2" } ]
2008-11-26
[ [ "Mavromatos", "Nick E.", "" ], [ "Meregaglia", "Anselmo", "" ], [ "Rubbia", "Andre", "" ], [ "Sakharov", "Alexander", "" ], [ "Sarkar", "Sarben", "" ] ]
Quantum decoherence, the evolution of pure states into mixed states, may be a feature of quantum-gravity models. In most cases, such models lead to fewer neutrinos of all active flavours being detected in a long baseline experiment as compared to three-flavour standard neutrino oscillations. We discuss the potential of the CNGS and J-PARC beams in constraining models of quantum-gravity induced decoherence using neutrino oscillations as a probe. We use as much as possible model-independent parameterizations, even though they are motivated by specific microscopic models, for fits to the expected experimental data which yield bounds on quantum-gravity decoherence parameters.
hep-ph/9508415
null
Tiehui (Ted) Liu
An Overview of $D^0\bar{D}^0$ Mixing Search Techniques: Current Status and Future Prospects
53 pages, 8 compressed figures appended at the end
AIP Conf.Proc.349:447-480,1996
null
PRINCETON/HEP/95-6
hep-ph
null
The search for $D^0\bar{D}^0$ mixing may carry a large discovery potential for new physics. This paper discusses the techniques, current experimental status, and future prospects for the mixing search. Some new ideas, applicable to future mixing searches, are introduced. In this paper, the importance of separately measuring the decay rate difference and the mass difference of the two CP eigenstates (in order to observe New Physics) has been emphasized, since the theoretical calculations for long distance effects are still plagued by large uncertainties.
[ { "created": "Thu, 31 Aug 1995 21:15:04 GMT", "version": "v1" }, { "created": "Fri, 1 Sep 1995 06:16:35 GMT", "version": "v2" } ]
2010-12-13
[ [ "Tiehui", "", "", "Ted" ], [ "Liu", "", "" ] ]
The search for $D^0\bar{D}^0$ mixing may carry a large discovery potential for new physics. This paper discusses the techniques, current experimental status, and future prospects for the mixing search. Some new ideas, applicable to future mixing searches, are introduced. In this paper, the importance of separately measuring the decay rate difference and the mass difference of the two CP eigenstates (in order to observe New Physics) has been emphasized, since the theoretical calculations for long distance effects are still plagued by large uncertainties.
1908.07524
Thomas Flacke
Giacomo Cacciapaglia, Thomas Flacke, Myeonghun Park, and Mengchao Zhang
Exotic decays of top partners: mind the search gap
10 pages, 6 figures, 3 tables; v2: typos fixed, references added, version published in PLB
null
10.1016/j.physletb.2019.135015
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Many standard model extensions, including composite Goldstone Higgs models, predict vector-like fermionic top-partners at the TeV scale. The intensive search programmes by ATLAS and CMS focus on decays into a 3$^{\rm rd}$ generation quark and an electroweak boson ($W,Z,h$). However, underlying models of partial compositeness contain additional states that give rise to exotic top partner decays. We consider a well-motivated scenario in which a charge-$2/3$ top-partner decays into a pseudo-scalar, $T\rightarrow t\ a$, with $a\rightarrow gg \mbox{ or } b\bar{b}$ dominating below the $t\bar{t}$ threshold. We show that the constraints on the top partner mass from QCD pair production are substantially weakened, still allowing a top partner mass as light as $400$ GeV.
[ { "created": "Tue, 20 Aug 2019 18:00:00 GMT", "version": "v1" }, { "created": "Mon, 21 Oct 2019 07:29:16 GMT", "version": "v2" } ]
2019-10-22
[ [ "Cacciapaglia", "Giacomo", "" ], [ "Flacke", "Thomas", "" ], [ "Park", "Myeonghun", "" ], [ "Zhang", "Mengchao", "" ] ]
Many standard model extensions, including composite Goldstone Higgs models, predict vector-like fermionic top-partners at the TeV scale. The intensive search programmes by ATLAS and CMS focus on decays into a 3$^{\rm rd}$ generation quark and an electroweak boson ($W,Z,h$). However, underlying models of partial compositeness contain additional states that give rise to exotic top partner decays. We consider a well-motivated scenario in which a charge-$2/3$ top-partner decays into a pseudo-scalar, $T\rightarrow t\ a$, with $a\rightarrow gg \mbox{ or } b\bar{b}$ dominating below the $t\bar{t}$ threshold. We show that the constraints on the top partner mass from QCD pair production are substantially weakened, still allowing a top partner mass as light as $400$ GeV.
hep-ph/0504168
Katri Huitu
E. Gabrielli, K. Huitu, and S. Khalil
Supersymmetric Models and CP violation in B decays
16 pages, 7 figures. Prepared for the proceedings of the 1st GUC workshop on High Energy Physics, Cairo, Jan 9-13, 2005
null
null
HIP-2005-11/TH
hep-ph
null
In this talk CP violation in the supersymmetric models, and especially in B-decays is discussed. We review our analysis of the supersymmetric contributions to the mixing CP asymmetries of $B\to \phi K_S$ and $B\to \eta^{\prime} K_S$ processes. Both gluino and chargino exchanges are considered in a model independent way by using the mass insertion approximation method. The QCD factorization method is used, and parametrization of this method in terms of Wilson coefficients is presented in both decay modes. Correlations between the CP asymmetries of these processes and the direct CP asymmetry in $b\to s \gamma$ decay are shown.
[ { "created": "Tue, 19 Apr 2005 15:03:27 GMT", "version": "v1" } ]
2007-05-23
[ [ "Gabrielli", "E.", "" ], [ "Huitu", "K.", "" ], [ "Khalil", "S.", "" ] ]
In this talk CP violation in the supersymmetric models, and especially in B-decays is discussed. We review our analysis of the supersymmetric contributions to the mixing CP asymmetries of $B\to \phi K_S$ and $B\to \eta^{\prime} K_S$ processes. Both gluino and chargino exchanges are considered in a model independent way by using the mass insertion approximation method. The QCD factorization method is used, and parametrization of this method in terms of Wilson coefficients is presented in both decay modes. Correlations between the CP asymmetries of these processes and the direct CP asymmetry in $b\to s \gamma$ decay are shown.
hep-ph/9602437
Chi-Keung Chow
Chi-Keung Chow
Spin Symmetry Without Heavy Quarks: Hyperon Form Factors In The Large $N_c$ Limit
11 pages in REVTeX, no figures
null
null
CLNS 96/1403
hep-ph
null
In the large $N_c$ limit, all hyperon decays involving the same quark diagram $Q\to Q'$ are described by a single weak form factor $\eta_{QQ'}(w)$. No assumption on the mass of $Q$ or $Q'$ is necessary, making our results applicable to both $b\to c$ and $c\to s$ transitions. This same form factor describes both $\Lambda_Q\to\Lambda_{Q'}$ and $\Sigma^{(*)}_Q\to\Sigma^{(*)}_{Q'}$ transitions. The (non-)commutativity between the heavy quark and the large $N_c$ limits is briefly discussed under the definite example of $\Lambda_b\to\Lambda_c$ decay.
[ { "created": "Thu, 29 Feb 1996 19:11:54 GMT", "version": "v1" } ]
2007-05-23
[ [ "Chow", "Chi-Keung", "" ] ]
In the large $N_c$ limit, all hyperon decays involving the same quark diagram $Q\to Q'$ are described by a single weak form factor $\eta_{QQ'}(w)$. No assumption on the mass of $Q$ or $Q'$ is necessary, making our results applicable to both $b\to c$ and $c\to s$ transitions. This same form factor describes both $\Lambda_Q\to\Lambda_{Q'}$ and $\Sigma^{(*)}_Q\to\Sigma^{(*)}_{Q'}$ transitions. The (non-)commutativity between the heavy quark and the large $N_c$ limits is briefly discussed under the definite example of $\Lambda_b\to\Lambda_c$ decay.
2002.01652
Felix Ringer
Jian-Wei Qiu, Felix Ringer, Nobuo Sato, Pia Zurita
QCD factorization and universality of jet cross sections in heavy-ion collisions
4 pages, 2 figures, XXVIIIth International Conference on Ultrarelativistic Nucleus-Nucleus Collisions (Quark Matter 2019)
null
10.1016/j.nuclphysa.2020.121853
null
hep-ph nucl-ex nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We review a recently proposed phenomenological framework to establish the notions of QCD factorization and universality of jet cross sections in the heavy-ion environment. First results of a global analysis of the nuclear modification factor of inclusive jets are presented where we extract medium modified jet functions using a Monte Carlo sampling approach. We observe that gluon jets are significantly more suppressed than quark jets. In addition, we study the jet radius dependence of the inclusive jet cross section in heavy-ion collisions and comment on a recent measurement from CMS. By considering for example jet substructure observables it will be possible to test the universality of the extracted medium jet functions. We thus expect that the presented results will eventually allow for extractions of medium properties with a reduced model bias.
[ { "created": "Wed, 5 Feb 2020 05:40:12 GMT", "version": "v1" } ]
2021-02-03
[ [ "Qiu", "Jian-Wei", "" ], [ "Ringer", "Felix", "" ], [ "Sato", "Nobuo", "" ], [ "Zurita", "Pia", "" ] ]
We review a recently proposed phenomenological framework to establish the notions of QCD factorization and universality of jet cross sections in the heavy-ion environment. First results of a global analysis of the nuclear modification factor of inclusive jets are presented where we extract medium modified jet functions using a Monte Carlo sampling approach. We observe that gluon jets are significantly more suppressed than quark jets. In addition, we study the jet radius dependence of the inclusive jet cross section in heavy-ion collisions and comment on a recent measurement from CMS. By considering for example jet substructure observables it will be possible to test the universality of the extracted medium jet functions. We thus expect that the presented results will eventually allow for extractions of medium properties with a reduced model bias.
1303.4021
Sergey Larin
S.A. Larin
The singlet contribution to the Bjorken sum rule for polarized deep inelastic scattering
7 pages
Phys.Lett. B723 (2013) 348-350
10.1016/j.physletb.2013.05.026
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It is shown that the existing four-loop result for the Bjorken polarized sum rule for deep inelastic electron-nucleon scattering obtained within perturbative Quantum Chromodynamics should be supplemented by the calculation of the diagrams of the so called singlet type. We also give an explanation of the interesting coincidence of two different classes of diagrams, one of the non-singlet and one of the singlet type, contributing the $\alpha_s^4$-approximation to the total cross-section of electron-positron annihilation into hadrons.
[ { "created": "Thu, 14 Mar 2013 16:43:05 GMT", "version": "v1" } ]
2015-06-15
[ [ "Larin", "S. A.", "" ] ]
It is shown that the existing four-loop result for the Bjorken polarized sum rule for deep inelastic electron-nucleon scattering obtained within perturbative Quantum Chromodynamics should be supplemented by the calculation of the diagrams of the so called singlet type. We also give an explanation of the interesting coincidence of two different classes of diagrams, one of the non-singlet and one of the singlet type, contributing the $\alpha_s^4$-approximation to the total cross-section of electron-positron annihilation into hadrons.
1710.06787
Sacha Davidson
Sacha Davidson, Yoshitaka Kuno and Albert Saporta
Spin-dependent ${\mu \to e}$ Conversion on Light Nuclei
typo corrected in eqn 33
null
10.1140/epjc/s10052-018-5584-8
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The experimental sensitivity to $\mu \to e$ conversion will improve by four or more orders of magnitude in coming years, making it interesting to consider the "spin-dependent" (SD) contribution to the rate. This process does not benefit from the atomic-number-squared enhancement of the spin-independent (SI) contribution, but probes different operators. We give details of our recent estimate of the spin dependent rate, expressed as a function of operator coefficients at the experimental scale, and explore the prospects for distinguishing coefficients by using different targets. For this purpose, a geometric representation of different targets as vectors in coefficient space is introduced. It is found that comparing the rate on isotopes with and without spin could allow to detect spin dependent coefficients that are at least a factor of few larger than the spin independent ones. Distinguishing among the axial, tensor and pseudoscalar operators that induce the SD rate would require calculating the nuclear matrix elements for the second two. Comparing the SD rate on nuclei with an odd proton vs odd neutron could allow to distinguish operators involving $u$ quarks from those involving $d$ quarks; this is interesting because the distinction is difficult to make for SI operators.
[ { "created": "Wed, 18 Oct 2017 15:34:26 GMT", "version": "v1" }, { "created": "Sat, 3 Feb 2018 06:34:52 GMT", "version": "v2" }, { "created": "Thu, 30 Aug 2018 10:52:35 GMT", "version": "v3" } ]
2018-08-31
[ [ "Davidson", "Sacha", "" ], [ "Kuno", "Yoshitaka", "" ], [ "Saporta", "Albert", "" ] ]
The experimental sensitivity to $\mu \to e$ conversion will improve by four or more orders of magnitude in coming years, making it interesting to consider the "spin-dependent" (SD) contribution to the rate. This process does not benefit from the atomic-number-squared enhancement of the spin-independent (SI) contribution, but probes different operators. We give details of our recent estimate of the spin dependent rate, expressed as a function of operator coefficients at the experimental scale, and explore the prospects for distinguishing coefficients by using different targets. For this purpose, a geometric representation of different targets as vectors in coefficient space is introduced. It is found that comparing the rate on isotopes with and without spin could allow to detect spin dependent coefficients that are at least a factor of few larger than the spin independent ones. Distinguishing among the axial, tensor and pseudoscalar operators that induce the SD rate would require calculating the nuclear matrix elements for the second two. Comparing the SD rate on nuclei with an odd proton vs odd neutron could allow to distinguish operators involving $u$ quarks from those involving $d$ quarks; this is interesting because the distinction is difficult to make for SI operators.
2006.00919
Victor Goncalves
V. P. Goncalves, L. Lazzari
Electrically charged strange stars with an interacting quark matter equation of state
9 pages, 4 figures. Improved version to be published in Physical Review D
Phys. Rev. D 102, 034031 (2020)
10.1103/PhysRevD.102.034031
null
hep-ph astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The properties of electrically charged strange quark stars predicted by an interacting quark matter equation of state (EoS) based on cold and dense perturbative quantum chromodynamics (pQCD) are investigated. The stability of strange stars is analyzed considering different models for the electric charge distribution inside the star as well as for distinct values for the total electric charge. A comparison with the predictions derived using the MIT bag model is also presented. We show that the presence of a net electric charge inside strange stars implies in a larger maximum mass in comparison to their neutral counterparts. Moreover, we demonstrate that the pQCD EoS implies larger values for the maximum mass of charged strange stars, with very heavy charged stars being stable systems against radial oscillations. For an electric charge distribution given by $q(r) = \beta r^3$, the pQCD EoS implies unstable configurations for large values of the renormalization scale as well as for large values of $\beta$, in contrast to the MIT bag model predictions.
[ { "created": "Mon, 1 Jun 2020 13:06:21 GMT", "version": "v1" }, { "created": "Mon, 17 Aug 2020 16:03:05 GMT", "version": "v2" } ]
2020-09-02
[ [ "Goncalves", "V. P.", "" ], [ "Lazzari", "L.", "" ] ]
The properties of electrically charged strange quark stars predicted by an interacting quark matter equation of state (EoS) based on cold and dense perturbative quantum chromodynamics (pQCD) are investigated. The stability of strange stars is analyzed considering different models for the electric charge distribution inside the star as well as for distinct values for the total electric charge. A comparison with the predictions derived using the MIT bag model is also presented. We show that the presence of a net electric charge inside strange stars implies in a larger maximum mass in comparison to their neutral counterparts. Moreover, we demonstrate that the pQCD EoS implies larger values for the maximum mass of charged strange stars, with very heavy charged stars being stable systems against radial oscillations. For an electric charge distribution given by $q(r) = \beta r^3$, the pQCD EoS implies unstable configurations for large values of the renormalization scale as well as for large values of $\beta$, in contrast to the MIT bag model predictions.
2002.01688
Axel Maas
Simon Fernbach, Lukas Lechner, Axel Maas, Simon Pl\"atzer, Robert Sch\"ofbeck
Constraining the Higgs valence contribution in the proton
19 pages, 7 figures, 2 tables; v2: Minor extensions and added references
Phys. Rev. D 101, 114018 (2020)
10.1103/PhysRevD.101.114018
UWTHPH-19-38
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Non-perturbative gauge-invariance under the strong and the weak interactions dictates that the proton contains a non-vanishing valence contribution from the Higgs particle. By introducing an additional parton distribution function (PDF), we investigate the experimental consequences of this prediction. The Herwig 7 event generator and a parametrized CMS detector simulation are used to obtain predictions for a scenario amounting to the LHC Run II data set. We use those to assess the impact of the Higgs PDF on the pp->ttbar process in the single lepton final state. Comparing to nominal simulation we derive expected limits as a function of the shape of the valence Higgs PDF. We also investigate the process pp->ttZ at the parton level to add further constraints.
[ { "created": "Wed, 5 Feb 2020 09:01:43 GMT", "version": "v1" }, { "created": "Fri, 19 Jun 2020 17:04:29 GMT", "version": "v2" } ]
2020-06-22
[ [ "Fernbach", "Simon", "" ], [ "Lechner", "Lukas", "" ], [ "Maas", "Axel", "" ], [ "Plätzer", "Simon", "" ], [ "Schöfbeck", "Robert", "" ] ]
Non-perturbative gauge-invariance under the strong and the weak interactions dictates that the proton contains a non-vanishing valence contribution from the Higgs particle. By introducing an additional parton distribution function (PDF), we investigate the experimental consequences of this prediction. The Herwig 7 event generator and a parametrized CMS detector simulation are used to obtain predictions for a scenario amounting to the LHC Run II data set. We use those to assess the impact of the Higgs PDF on the pp->ttbar process in the single lepton final state. Comparing to nominal simulation we derive expected limits as a function of the shape of the valence Higgs PDF. We also investigate the process pp->ttZ at the parton level to add further constraints.
hep-ph/9811418
null
S. Alekhin, V. Borodulin (IHEP, Protvino), A. Celikel, M. Kantar, S. Sultansoy (Ankara Univ., Ankara)
Probing a Nucleon Spin Structure at TESLA by the Real Polarized Gamma Beam
16 pages, LATEX, 6 figures (EPS)
Eur.Phys.J.C11:301-307,1999
10.1007/s100520050634
null
hep-ph
null
The recent proposals concerning the usage of the real polarized gamma beam, obtained by the Compton backscattering of the laser photons off the electron beams from either the linear or circular accelerators were considered. The heavy quark photoproduction process giving a unique opportunity to measure polarized gluon distribution was investigated.
[ { "created": "Fri, 20 Nov 1998 10:21:59 GMT", "version": "v1" } ]
2011-09-13
[ [ "Alekhin", "S.", "", "IHEP, Protvino" ], [ "Borodulin", "V.", "", "IHEP, Protvino" ], [ "Celikel", "A.", "", "Ankara Univ., Ankara" ], [ "Kantar", "M.", "", "Ankara Univ., Ankara" ], [ "Sultansoy", "S.", "", "Ankara Univ., Ankara" ] ]
The recent proposals concerning the usage of the real polarized gamma beam, obtained by the Compton backscattering of the laser photons off the electron beams from either the linear or circular accelerators were considered. The heavy quark photoproduction process giving a unique opportunity to measure polarized gluon distribution was investigated.
hep-ph/9905286
Abe Hiroyuki
H. Abe, J. Hashida, T. Muta and A. Purwanto
Path-Integral Formulation of Casimir Effects in Supersymmetric Quantum Electrodynamics
12 pages, 6 figures, REVTeX
Mod.Phys.Lett. A14 (1999) 1033-1042
10.1142/S0217732399001097
HUPD-9906
hep-ph
null
The Casimir effect is an interesting phenomenon in the sense that it provides us with one of the primitive means of extracting the energy out of the vacuum. Since the original work of Casimir a number of works have appeared in extending the result to the case of more general topological and dynamical configurations of the boundary condition and to the circumstances at finite temperature and gravity. In the studies of the Casimir effects it is common to assume the free electromagnetic field in the bounded region. It may be interesting to extend our arguments for fields other than the electromagnetic field. The Casimir effect due to the free fermionic fields has been investigated by several authors and has been found to result in an attractive force under the suitable physical boundary conditions.
[ { "created": "Mon, 10 May 1999 15:12:21 GMT", "version": "v1" } ]
2009-10-31
[ [ "Abe", "H.", "" ], [ "Hashida", "J.", "" ], [ "Muta", "T.", "" ], [ "Purwanto", "A.", "" ] ]
The Casimir effect is an interesting phenomenon in the sense that it provides us with one of the primitive means of extracting the energy out of the vacuum. Since the original work of Casimir a number of works have appeared in extending the result to the case of more general topological and dynamical configurations of the boundary condition and to the circumstances at finite temperature and gravity. In the studies of the Casimir effects it is common to assume the free electromagnetic field in the bounded region. It may be interesting to extend our arguments for fields other than the electromagnetic field. The Casimir effect due to the free fermionic fields has been investigated by several authors and has been found to result in an attractive force under the suitable physical boundary conditions.
1909.09740
Roman Pasechnik
Andrea Addazi, Antonino Marcian\`o, Ant\'onio P. Morais, Roman Pasechnik, Rahul Srivastava and Jos\'e W. F. Valle
Gravitational footprints of massive neutrinos and lepton number breaking
11 pages, 5 figures, 4 tables; invisible Higgs decay constraint incorporated; discussion extended; references added
null
10.1016/j.physletb.2020.135577
IFIC/19-XXX
hep-ph astro-ph.CO gr-qc hep-ex hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate the production of primordial Gravitational Waves (GWs) arising from First Order Phase Transitions (FOPTs) associated to neutrino mass generation in the context of type-I and inverse seesaw schemes. We examine both "high-scale" as well as "low-scale" variants, with either explicit or spontaneously broken lepton number symmetry $U(1)_L$ in the neutrino sector. In the latter case, a pseudo-Goldstone majoron-like boson may provide a candidate for cosmological dark matter. We find that schemes with softly-broken $U(1)_L$ and with single Higgs-doublet scalar sector lead to either no FOPTs or too weak FOPTs, precluding the detectability of GWs in present or near future measurements. Nevertheless, we found that, in the majoron-like seesaw scheme with spontaneously broken $U(1)_L$ at finite temperatures, one can have strong FOPTs and non-trivial primordial GW spectra which can fall well within the frequency and amplitude sensitivity of upcoming experiments, including LISA, BBO and u-DECIGO. However, GWs observability clashes with invisible Higgs decay constraints from the LHC. A simple and consistent fix is to assume the majoron-like mass to lie above the Higgs-decay kinematical threshold. We also found that the majoron-like variant of the low-scale seesaw mechanism implies a different GW spectrum than the one expected in the high-scale seesaw. This feature will be testable in future experiments. Our analysis shows that GWs can provide a new and complementary portal to test the neutrino mass generation mechanism.
[ { "created": "Fri, 20 Sep 2019 23:24:05 GMT", "version": "v1" }, { "created": "Sat, 2 May 2020 20:44:30 GMT", "version": "v2" } ]
2020-07-01
[ [ "Addazi", "Andrea", "" ], [ "Marcianò", "Antonino", "" ], [ "Morais", "António P.", "" ], [ "Pasechnik", "Roman", "" ], [ "Srivastava", "Rahul", "" ], [ "Valle", "José W. F.", "" ] ]
We investigate the production of primordial Gravitational Waves (GWs) arising from First Order Phase Transitions (FOPTs) associated to neutrino mass generation in the context of type-I and inverse seesaw schemes. We examine both "high-scale" as well as "low-scale" variants, with either explicit or spontaneously broken lepton number symmetry $U(1)_L$ in the neutrino sector. In the latter case, a pseudo-Goldstone majoron-like boson may provide a candidate for cosmological dark matter. We find that schemes with softly-broken $U(1)_L$ and with single Higgs-doublet scalar sector lead to either no FOPTs or too weak FOPTs, precluding the detectability of GWs in present or near future measurements. Nevertheless, we found that, in the majoron-like seesaw scheme with spontaneously broken $U(1)_L$ at finite temperatures, one can have strong FOPTs and non-trivial primordial GW spectra which can fall well within the frequency and amplitude sensitivity of upcoming experiments, including LISA, BBO and u-DECIGO. However, GWs observability clashes with invisible Higgs decay constraints from the LHC. A simple and consistent fix is to assume the majoron-like mass to lie above the Higgs-decay kinematical threshold. We also found that the majoron-like variant of the low-scale seesaw mechanism implies a different GW spectrum than the one expected in the high-scale seesaw. This feature will be testable in future experiments. Our analysis shows that GWs can provide a new and complementary portal to test the neutrino mass generation mechanism.
hep-ph/0305247
Donini Andrea
A. Donini
Using nu_e -> nu_tau: golden and silver channels at the Neutrino Factory
6 pages, 7 figs. using epsfig; proceedings of the NOON 2003 Workshop, February 10-14, 2003, Kanazawa, Japan
null
10.1142/9789812703101_0024
null
hep-ph
null
I briefly review the source of the so-called intrinsic ambiguity and show how the combination of ``golden'' and ``silver'' channel at the Neutrino Factory can solve the problem, in the absence of other sources of degeneracies. I then relaxed the hypothesis $\theta_{23} = 45^\circ$ and show how the different dependence of the two channels on $\theta_{23}$ can help in solving the intrinsic and $\theta_{23}$-octant ambiguity at the same time.
[ { "created": "Thu, 22 May 2003 10:38:23 GMT", "version": "v1" } ]
2017-08-23
[ [ "Donini", "A.", "" ] ]
I briefly review the source of the so-called intrinsic ambiguity and show how the combination of ``golden'' and ``silver'' channel at the Neutrino Factory can solve the problem, in the absence of other sources of degeneracies. I then relaxed the hypothesis $\theta_{23} = 45^\circ$ and show how the different dependence of the two channels on $\theta_{23}$ can help in solving the intrinsic and $\theta_{23}$-octant ambiguity at the same time.
1905.00588
Murat Koksal
E. Alici and M. K\"oksal
Probing the anomalous $tq\gamma$ couplings through single top production at the future lepton-hadron colliders
13 pages 8 figures and 4 tables
Modern Physics Letters A, Vol. 34, No. 36 (2019) 1950298
10.1142/S0217732319502985
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The measurements of the top quark flavor changing neutral current interactions are one of the most important goals of the top quark physics program in the present and the future collider experiments. These measurements provide direct information on non-standard interactions of the top quark. Within the framework of new physics beyond the Standard Model, these interactions can be defined by an effective Lagrangian. In this study, we have investigated the potential of the future $\mu p$ colliders on the top quark flavor changing neutral current interactions through the subprocesses $\gamma q \rightarrow t \rightarrow W b$ where $q=u,c$. These subprocesses have been produced through the main reaction $\mu p \rightarrow \mu \gamma p \rightarrow \mu W b X $ at the LHC$-\mu p$, the FCC$-\mu p$ and the SPPC-$\mu p$. For the main reaction, the total cross sections have been calculated as a function of the anomalous $ tq\gamma $ couplings. In addition, sensitivities on BR($t \rightarrow q \gamma$) at $95\%$ Confidence Level have been calculated. We obtain that the best constraints on BR($t \rightarrow q \gamma$) are at the order of 10$^{-7}$ which is four orders of magnitude better than the LHC's experimental results.
[ { "created": "Thu, 2 May 2019 06:49:55 GMT", "version": "v1" }, { "created": "Fri, 29 Nov 2019 15:14:49 GMT", "version": "v2" } ]
2019-12-02
[ [ "Alici", "E.", "" ], [ "Köksal", "M.", "" ] ]
The measurements of the top quark flavor changing neutral current interactions are one of the most important goals of the top quark physics program in the present and the future collider experiments. These measurements provide direct information on non-standard interactions of the top quark. Within the framework of new physics beyond the Standard Model, these interactions can be defined by an effective Lagrangian. In this study, we have investigated the potential of the future $\mu p$ colliders on the top quark flavor changing neutral current interactions through the subprocesses $\gamma q \rightarrow t \rightarrow W b$ where $q=u,c$. These subprocesses have been produced through the main reaction $\mu p \rightarrow \mu \gamma p \rightarrow \mu W b X $ at the LHC$-\mu p$, the FCC$-\mu p$ and the SPPC-$\mu p$. For the main reaction, the total cross sections have been calculated as a function of the anomalous $ tq\gamma $ couplings. In addition, sensitivities on BR($t \rightarrow q \gamma$) at $95\%$ Confidence Level have been calculated. We obtain that the best constraints on BR($t \rightarrow q \gamma$) are at the order of 10$^{-7}$ which is four orders of magnitude better than the LHC's experimental results.
1903.04977
Tomas Gonzalo
Djuna Croon, Tom\'as E. Gonzalo, Lukas Graf, Nejc Ko\v{s}nik, Graham White
GUT Physics in the era of the LHC
92 pages, 19 figures, 3 tables. Updated to match published version
Front.in Phys. 7 (2019) 76
10.3389/fphy.2019.00076
CoEPP-MN-19-01
hep-ph hep-th
http://creativecommons.org/licenses/by/4.0/
Grand Unified Theories (GUTs) are one of the most interesting high-energy completions of the Standard Model, because they provide a rich, powerful and elegant group-theoretical framework able to resolve a variety of problems remaining in our current understanding of particle physics. They usually act as motivators for many low energy BSM theories, such as left-right symmetric or supersymmetric models, and they serve to fill the gap between the experimentally reachable low energies and the physics in the ultraviolet. In recent years, however, they have fallen slightly from the spotlight, in favour of `simplified' models with more specific phenomenological predictions. The aim of this review is to summarize the state of the art on GUTs and argue for their importance in modern physics. Recent advances in experiments permit to test the predictions of GUTs at different energy scales. First, as GUTs can play a role in the inflationary dynamics of the early Universe, their imprints could be found in the CMB observations by the Planck satellite. Remarkably enough, GUTs could manifest themselves also in terrestrial tests; several planned experiments aim to probe the proton stability and to establish order of magnitude higher bounds on its lifetime. Moreover, the predictions of specific GUT models could be tested even at the LHC thanks to its high energy reach, via searches for exotic states or additional contributions to flavour anomalies.
[ { "created": "Tue, 12 Mar 2019 15:07:15 GMT", "version": "v1" }, { "created": "Thu, 11 Jul 2019 04:23:52 GMT", "version": "v2" } ]
2019-07-12
[ [ "Croon", "Djuna", "" ], [ "Gonzalo", "Tomás E.", "" ], [ "Graf", "Lukas", "" ], [ "Košnik", "Nejc", "" ], [ "White", "Graham", "" ] ]
Grand Unified Theories (GUTs) are one of the most interesting high-energy completions of the Standard Model, because they provide a rich, powerful and elegant group-theoretical framework able to resolve a variety of problems remaining in our current understanding of particle physics. They usually act as motivators for many low energy BSM theories, such as left-right symmetric or supersymmetric models, and they serve to fill the gap between the experimentally reachable low energies and the physics in the ultraviolet. In recent years, however, they have fallen slightly from the spotlight, in favour of `simplified' models with more specific phenomenological predictions. The aim of this review is to summarize the state of the art on GUTs and argue for their importance in modern physics. Recent advances in experiments permit to test the predictions of GUTs at different energy scales. First, as GUTs can play a role in the inflationary dynamics of the early Universe, their imprints could be found in the CMB observations by the Planck satellite. Remarkably enough, GUTs could manifest themselves also in terrestrial tests; several planned experiments aim to probe the proton stability and to establish order of magnitude higher bounds on its lifetime. Moreover, the predictions of specific GUT models could be tested even at the LHC thanks to its high energy reach, via searches for exotic states or additional contributions to flavour anomalies.
2208.02196
Yu Fu
Yu Fu, Jacopo Ghiglieri, Shahin Iqbal, Aleksi Kurkela
Thermalization of weakly coupled non-Abelian plasmas at next-to-leading order
null
Acta Phys. Pol. B Proc. Suppl. 16, 1-A31 (2023)
10.5506/APhysPolBSupp.16.1-A31
null
hep-ph
http://creativecommons.org/licenses/by/4.0/
We employ the QCD kinetic theory, including next-to-leading(NLO) order corrections in coupling constant, to study the evolution of weakly coupled non-Abelian plasmas towards thermal equilibrium. For two characteristic far-from-equilibrium systems with either under- or over-occupied initial conditions, the NLO corrections remain well under control for a wide range of couplings, and the overall effect of NLO corrections is a reduction in the time required for thermalization.
[ { "created": "Wed, 3 Aug 2022 16:30:18 GMT", "version": "v1" } ]
2023-03-27
[ [ "Fu", "Yu", "" ], [ "Ghiglieri", "Jacopo", "" ], [ "Iqbal", "Shahin", "" ], [ "Kurkela", "Aleksi", "" ] ]
We employ the QCD kinetic theory, including next-to-leading(NLO) order corrections in coupling constant, to study the evolution of weakly coupled non-Abelian plasmas towards thermal equilibrium. For two characteristic far-from-equilibrium systems with either under- or over-occupied initial conditions, the NLO corrections remain well under control for a wide range of couplings, and the overall effect of NLO corrections is a reduction in the time required for thermalization.
2003.08130
Helmut Satz
Helmut Satz
Self-Organized Criticality
9 pages, 4 figures, invited talk at the 40th Max-Born-Symposium, Wroclaw/Poland, Oct. 9-11, 2019
null
null
null
hep-ph hep-ex hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We apply the concept of self-organized criticality in statistical physics to the study of multihadron production in high energy collisions.
[ { "created": "Wed, 18 Mar 2020 10:10:00 GMT", "version": "v1" } ]
2020-03-19
[ [ "Satz", "Helmut", "" ] ]
We apply the concept of self-organized criticality in statistical physics to the study of multihadron production in high energy collisions.
1706.06326
Mario Mitter
Anton K. Cyrol, Mario Mitter, Jan M. Pawlowski, Nils Strodthoff
Non-perturbative quark, gluon and meson correlators of unquenched QCD
null
Phys. Rev. D 97, 054006 (2018)
10.1103/PhysRevD.97.054006
null
hep-ph hep-lat hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present non-perturbative first-principle results for quark-, gluon- and meson $1$PI correlation functions of two-flavour Landau-gauge QCD in the vacuum. These correlation functions carry the full information about the theory. They are obtained by solving their Functional Renormalisation Group equations in a systematic vertex expansion, aiming at apparent convergence. This work represents a crucial prerequisite for quantitative first-principle studies of the QCD phase diagram and the hadron spectrum within this framework. In particular, we have computed the gluon, ghost, quark and scalar-pseudoscalar meson propagators, as well as gluon, ghost-gluon, quark-gluon, quark, quark-meson, and meson interactions. Our results stress the crucial importance of the quantitatively correct running of different vertices in the semi-perturbative regime for describing the phenomena and scales of confinement and spontaneous chiral symmetry breaking without phenomenological input.
[ { "created": "Tue, 20 Jun 2017 09:03:29 GMT", "version": "v1" } ]
2018-03-14
[ [ "Cyrol", "Anton K.", "" ], [ "Mitter", "Mario", "" ], [ "Pawlowski", "Jan M.", "" ], [ "Strodthoff", "Nils", "" ] ]
We present non-perturbative first-principle results for quark-, gluon- and meson $1$PI correlation functions of two-flavour Landau-gauge QCD in the vacuum. These correlation functions carry the full information about the theory. They are obtained by solving their Functional Renormalisation Group equations in a systematic vertex expansion, aiming at apparent convergence. This work represents a crucial prerequisite for quantitative first-principle studies of the QCD phase diagram and the hadron spectrum within this framework. In particular, we have computed the gluon, ghost, quark and scalar-pseudoscalar meson propagators, as well as gluon, ghost-gluon, quark-gluon, quark, quark-meson, and meson interactions. Our results stress the crucial importance of the quantitatively correct running of different vertices in the semi-perturbative regime for describing the phenomena and scales of confinement and spontaneous chiral symmetry breaking without phenomenological input.
hep-ph/9902393
Xiangdong Ji
Xiangdong Ji and Jonathan Osborne (U. Maryland)
Simplification of Higher-Twist Evolution in the Large N_c Limit: Why and Why Not
8 pages, latex, figures included
Eur.Phys.J.C9:487-490,1999
10.1007/s100529900095
UMD PP#99-045
hep-ph
null
Working in the light-cone gauge, we find a simple procedure to calculate the autonomous one-loop Q^2 evolution of the twist-three part of the nucleon g_T(x, Q^2) structure function in the large-N_c limit. Our approach allows us to investigate the possibility of a similar large-N_c simplification for other higher-twist evolutions. In particular, we show that it does not occur for the twist-four part of the f_4(x, Q^2), g_3(x, Q^2) and h_3(x, Q^2) distributions. We also argue that the simplification of the twist-three evolution does not persist beyond one loop.
[ { "created": "Thu, 18 Feb 1999 20:44:31 GMT", "version": "v1" } ]
2011-09-13
[ [ "Ji", "Xiangdong", "", "U. Maryland" ], [ "Osborne", "Jonathan", "", "U. Maryland" ] ]
Working in the light-cone gauge, we find a simple procedure to calculate the autonomous one-loop Q^2 evolution of the twist-three part of the nucleon g_T(x, Q^2) structure function in the large-N_c limit. Our approach allows us to investigate the possibility of a similar large-N_c simplification for other higher-twist evolutions. In particular, we show that it does not occur for the twist-four part of the f_4(x, Q^2), g_3(x, Q^2) and h_3(x, Q^2) distributions. We also argue that the simplification of the twist-three evolution does not persist beyond one loop.
hep-ph/0211252
Rabindra Nath Mohapatra
R. N. Mohapatra
ICTP Lectures on Theoretical Aspects of Neutrino Masses and Mixings
60 pages, latex, no figures, UMD-PP-03-22
null
null
null
hep-ph
null
Recent neutrino oscillation experiments are yielding valuable information on the nature of neutrino masses and mixings even though we are far from a complete understanding of the new physics implied by them. In these lectures, I summarize the current theoretical status of neutrino mass physics.
[ { "created": "Fri, 15 Nov 2002 21:20:38 GMT", "version": "v1" } ]
2007-05-23
[ [ "Mohapatra", "R. N.", "" ] ]
Recent neutrino oscillation experiments are yielding valuable information on the nature of neutrino masses and mixings even though we are far from a complete understanding of the new physics implied by them. In these lectures, I summarize the current theoretical status of neutrino mass physics.
hep-ph/9809218
Konstantin Klimenko
K.G. Klimenko
Magnetic Catalysis and Oscillating Effects in Nambu -- Jona-Lasinio Model at Nonzero Chemical Potential
LaTeX, 17 pages; Minor corrections; Extended version of Poster Talk given at the "5th International Workshop on Thermal Field Theories and Their Application", 10-14 August 1998, Regensburg, Germany
null
null
preprint IHEP 98-56
hep-ph hep-th nucl-th
null
Phase structure of the four dimensional Nambu -- Jona-Lasinio model has been investigated in two cases: 1) in nonsimply connected space-time of the form $R^3\times S^1$ (space coordinate is compactified and the length of the circle $S^1$ is $L$) with nonzero chemical potential $\mu$ and 2) in Minkowski space-time at nonzero values of $\mu,H$, where $H$ is the external magnetic field. In both cases on phase portraits of the model there are infinitly many massless chirally symmetric phases as well as massive ones with spontaneously broken chiral invariance. Such phase structure leads unavoidably to oscillations of some physical parameters at $L\to\infty$ or $H\to 0$, including magnetization, pressure and particle density of the system as well as quark condensate and critical curve of chiral phase transitions. Phase transitions of 1st and 2nd orders and several tricritical points have been shown to exist on phase diagrams of the model.
[ { "created": "Tue, 1 Sep 1998 14:50:22 GMT", "version": "v1" }, { "created": "Tue, 8 Sep 1998 10:23:00 GMT", "version": "v2" } ]
2007-05-23
[ [ "Klimenko", "K. G.", "" ] ]
Phase structure of the four dimensional Nambu -- Jona-Lasinio model has been investigated in two cases: 1) in nonsimply connected space-time of the form $R^3\times S^1$ (space coordinate is compactified and the length of the circle $S^1$ is $L$) with nonzero chemical potential $\mu$ and 2) in Minkowski space-time at nonzero values of $\mu,H$, where $H$ is the external magnetic field. In both cases on phase portraits of the model there are infinitly many massless chirally symmetric phases as well as massive ones with spontaneously broken chiral invariance. Such phase structure leads unavoidably to oscillations of some physical parameters at $L\to\infty$ or $H\to 0$, including magnetization, pressure and particle density of the system as well as quark condensate and critical curve of chiral phase transitions. Phase transitions of 1st and 2nd orders and several tricritical points have been shown to exist on phase diagrams of the model.
hep-ph/0510132
Masaki Yasue
Ichiro Aizawa and Masaki Yasue
A New Type of Complex Neutrino Mass Texture and mu-tau Symmetry
12 pages, RevTex, references updated, version to appear in Phys. Rev. D
Phys.Rev.D73:015002,2006
10.1103/PhysRevD.73.015002
TOKAI-HEP/TH-0505
hep-ph
null
Relying upon the usefulness of the \mu-\tau symmetry, we find a new type of neutrino mass texture with a single phase parameter \delta that describes maximal atmospheric neutrino mixing and Dirac CP violation due to the presence of \delta. The Majorana phase associated with the third massive neutrino turns out to be identical to the Dirac phase while other Majorana phases vanish. The nonvanishing reactor neutrino mixing angle \theta_{13} is induced by a \mu-\tau symmetry breaking effect. Flavor neutrino masses that supply the \mu-\tau symmetry breaking terms become pure imaginary for \delta=\pm \pi/2, leading to maximal CP violation. There is a parameter denoted by \eta, which is either O(\sqrt{\Delta m^2_\odot/\Delta m^2_{atm}}) in the normal mass hierarchy, or O(\Delta m^2_\odot/\Delta m^2_{atm}) in the inverted mass hierarchy. In the inverted mass hierarchy, the contribution of O(\sin^2\theta_{13}) is found to be significant and cannot be neglected. Our texture also leads to quasi degenerate neutrinos with masses of O(\sqrt{\Delta m^2_{atm}}), which serves as the scale for the effective neutrino mass in (\beta\beta)_{0\nu}-decay. This texture does not include \eta, and \Delta m^2_\odot naturally arises from contributions of O(\sin^2\theta_{13}) to give \Delta m^2_\odot/\Delta m^2_{atm}\sim\sin^2\theta_{13}, yielding the prediction of \sin^2\theta_{13}=O(10^{-2}).
[ { "created": "Tue, 11 Oct 2005 15:01:36 GMT", "version": "v1" }, { "created": "Mon, 7 Nov 2005 07:29:22 GMT", "version": "v2" }, { "created": "Tue, 27 Dec 2005 07:01:16 GMT", "version": "v3" } ]
2014-11-18
[ [ "Aizawa", "Ichiro", "" ], [ "Yasue", "Masaki", "" ] ]
Relying upon the usefulness of the \mu-\tau symmetry, we find a new type of neutrino mass texture with a single phase parameter \delta that describes maximal atmospheric neutrino mixing and Dirac CP violation due to the presence of \delta. The Majorana phase associated with the third massive neutrino turns out to be identical to the Dirac phase while other Majorana phases vanish. The nonvanishing reactor neutrino mixing angle \theta_{13} is induced by a \mu-\tau symmetry breaking effect. Flavor neutrino masses that supply the \mu-\tau symmetry breaking terms become pure imaginary for \delta=\pm \pi/2, leading to maximal CP violation. There is a parameter denoted by \eta, which is either O(\sqrt{\Delta m^2_\odot/\Delta m^2_{atm}}) in the normal mass hierarchy, or O(\Delta m^2_\odot/\Delta m^2_{atm}) in the inverted mass hierarchy. In the inverted mass hierarchy, the contribution of O(\sin^2\theta_{13}) is found to be significant and cannot be neglected. Our texture also leads to quasi degenerate neutrinos with masses of O(\sqrt{\Delta m^2_{atm}}), which serves as the scale for the effective neutrino mass in (\beta\beta)_{0\nu}-decay. This texture does not include \eta, and \Delta m^2_\odot naturally arises from contributions of O(\sin^2\theta_{13}) to give \Delta m^2_\odot/\Delta m^2_{atm}\sim\sin^2\theta_{13}, yielding the prediction of \sin^2\theta_{13}=O(10^{-2}).
hep-ph/9806330
Howard E. Haber
John F. Gunion and Howard E. Haber
Low-Energy Supersymmetry at Future Colliders
21 pages, needs sprocl.sty, to appear in "Perspectives on Supersymmetry" (edited by Gordon L. Kane), to be published by World Scientific
null
null
SCIPP 97/37 and UCD-97-29
hep-ph
null
We classify the variety of low-energy supersymmetric signatures that can be probed at future colliders. We focus on phenomena associated with the minimal supersymmetric extension of the Standard Model. The structure of the supersymmetry-breaking introduces additional model assumptions. The approaches considered here are supergravity-mediated and gauge-mediated supersymmetry-breaking. Alternative phenomenologies arising in non-minimal and/or R-parity-violating approaches are also briefly examined.
[ { "created": "Wed, 10 Jun 1998 00:28:31 GMT", "version": "v1" } ]
2007-05-23
[ [ "Gunion", "John F.", "" ], [ "Haber", "Howard E.", "" ] ]
We classify the variety of low-energy supersymmetric signatures that can be probed at future colliders. We focus on phenomena associated with the minimal supersymmetric extension of the Standard Model. The structure of the supersymmetry-breaking introduces additional model assumptions. The approaches considered here are supergravity-mediated and gauge-mediated supersymmetry-breaking. Alternative phenomenologies arising in non-minimal and/or R-parity-violating approaches are also briefly examined.
1201.1543
Satyajit Seth
M. C. Kumar, Prakash Mathews, V. Ravindran, Satyajit Seth
Associated production of vector gauge boson & graviton to NLO QCD
8 pages, 5 figures, Proceeding: 10th International Symposium on Radiative Corrections (RADCOR 2011); Mamallapuram, India
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this talk, we discuss the next-to-leading order (NLO) QCD corrections to the associated production of the vector gauge boson (Z/W\pm) and the graviton in the large extra dimension model, namely the ADD model, at the LHC. After a brief review of the ADD model, we present the importance of QCD correction to these preferred processes and the impact of the QCD corrections on the total cross sections as well as the differential distributions of the gauge bosons. The dependence of the cross sections on the arbitrary factorization scale is studied and the reduction in the scale uncertainties at NLO level is shown. The ultraviolet sensitivity of the theoretical prediction is also presented.
[ { "created": "Sat, 7 Jan 2012 10:41:25 GMT", "version": "v1" } ]
2012-01-10
[ [ "Kumar", "M. C.", "" ], [ "Mathews", "Prakash", "" ], [ "Ravindran", "V.", "" ], [ "Seth", "Satyajit", "" ] ]
In this talk, we discuss the next-to-leading order (NLO) QCD corrections to the associated production of the vector gauge boson (Z/W\pm) and the graviton in the large extra dimension model, namely the ADD model, at the LHC. After a brief review of the ADD model, we present the importance of QCD correction to these preferred processes and the impact of the QCD corrections on the total cross sections as well as the differential distributions of the gauge bosons. The dependence of the cross sections on the arbitrary factorization scale is studied and the reduction in the scale uncertainties at NLO level is shown. The ultraviolet sensitivity of the theoretical prediction is also presented.
2311.05859
Ernest Ma
Ernest Ma
Softly Broken Hidden Symmetry in Every Renormalizable Field Theory
7 pages, no figure, text expanded to explain the difference between explicit and spontaneous $Z_4 \to Z_2$ breaking
null
null
UCRHEP-T626, Nov 10, 2023
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It is pointed out that every renormalizable field theory has a symmetry which is hidden in plain sight. In all practical cases, it is also broken softly, either explicitly or spontaneously. Implications for neutrino mass and dark matter are discussed.
[ { "created": "Fri, 10 Nov 2023 04:06:58 GMT", "version": "v1" }, { "created": "Thu, 28 Dec 2023 23:30:32 GMT", "version": "v2" } ]
2024-01-01
[ [ "Ma", "Ernest", "" ] ]
It is pointed out that every renormalizable field theory has a symmetry which is hidden in plain sight. In all practical cases, it is also broken softly, either explicitly or spontaneously. Implications for neutrino mass and dark matter are discussed.
2201.05412
Takashi Toma
Takumi Miyagi and Takashi Toma
Semi-annihilating dark matter coupled with Majorons
19 pages, 5 figures
JHEP 07 (2022) 027
10.1007/JHEP07(2022)027
KANAZAWA-22-01
hep-ph astro-ph.CO astro-ph.HE
http://creativecommons.org/licenses/by/4.0/
The thermal production mechanism of dark matter is attractive and well-motivated by predictivity. A representative of this type of dark matter candidate is the canonical, weakly interacting massive particles. An alternative is semi-annihilating dark matter, which exhibits different phenomenological aspects from the former example. In this study, we constructed a model of dark matter semi-annihilating into a pair of anti-dark matter and a Majoron based on a global $U(1)_{B-L}$ symmetry, and show that semi-annihilation induces the core formation of dark matter halos, which can alleviate the so-called small-scale problems. In addition, the box-shaped spectrum of neutrinos was produced by the subsequent decay of the Majoron. This can be a distinctive signature of the dark matter in the model. We find a parameter space where the produced neutrinos can be detected by the future large-volume neutrino detector Hyper-Kamiokande. We also compared the dark matter scenario with the case of halo core formation by the strongly self-interacting dark matter.
[ { "created": "Fri, 14 Jan 2022 12:09:25 GMT", "version": "v1" }, { "created": "Wed, 6 Jul 2022 09:39:59 GMT", "version": "v2" } ]
2022-07-07
[ [ "Miyagi", "Takumi", "" ], [ "Toma", "Takashi", "" ] ]
The thermal production mechanism of dark matter is attractive and well-motivated by predictivity. A representative of this type of dark matter candidate is the canonical, weakly interacting massive particles. An alternative is semi-annihilating dark matter, which exhibits different phenomenological aspects from the former example. In this study, we constructed a model of dark matter semi-annihilating into a pair of anti-dark matter and a Majoron based on a global $U(1)_{B-L}$ symmetry, and show that semi-annihilation induces the core formation of dark matter halos, which can alleviate the so-called small-scale problems. In addition, the box-shaped spectrum of neutrinos was produced by the subsequent decay of the Majoron. This can be a distinctive signature of the dark matter in the model. We find a parameter space where the produced neutrinos can be detected by the future large-volume neutrino detector Hyper-Kamiokande. We also compared the dark matter scenario with the case of halo core formation by the strongly self-interacting dark matter.
hep-ph/0206032
Dmitry Naumov
Dmitry V. Naumov (for the NOMAD Collaboration)
Measurement of Lambda and Lambda-bar polarization in muon neutrino charged current interactions in NOMAD
5 pages, a contrubution to DIS2002 Conference, Cracow (April, 29 - May, 4)
Acta Phys.Polon. B33 (2002) 3791-3796
null
null
hep-ph
null
The Lambda and Lambda-bar polarizations in muon neutrino charged current interactions have been measured in the NOMAD experiment. The event sample (8087 reconstructed Lambda's and 649 Lambda-bar's) is more than an order of magnitude larger than that of previous bubble chamber experiments, while the quality of event reconstruction is comparable. For the Lambda hyperons we observe negative polarization along the W-boson direction which is enhanced in the target fragmentation region: Px(xF < 0) = -0.21 +- 0.04 (stat) +- 0.02 (sys). In the current fragmentation region we find Px(xF > 0) = -0.09 +- 0.06 (stat) +- 0.03(sys). A significant transverse polarization (in the direction orthogonal to the Lambda production plane) has been observed for the first time in a neutrino experiment: Py = -0.22 +- 0.03 (stat) +- 0.01 (sys). The dependence of the absolute value of Py on the Lambda transverse momentum with respect to the hadronic jet direction is in qualitative agreement with the results from unpolarized hadron-hadron experiments. The polarization vector of Lambda-bar hyperons measured for the first time in neutrino interactions is found to be consistent with zero.
[ { "created": "Tue, 4 Jun 2002 15:51:04 GMT", "version": "v1" } ]
2007-05-23
[ [ "Naumov", "Dmitry V.", "", "for the NOMAD Collaboration" ] ]
The Lambda and Lambda-bar polarizations in muon neutrino charged current interactions have been measured in the NOMAD experiment. The event sample (8087 reconstructed Lambda's and 649 Lambda-bar's) is more than an order of magnitude larger than that of previous bubble chamber experiments, while the quality of event reconstruction is comparable. For the Lambda hyperons we observe negative polarization along the W-boson direction which is enhanced in the target fragmentation region: Px(xF < 0) = -0.21 +- 0.04 (stat) +- 0.02 (sys). In the current fragmentation region we find Px(xF > 0) = -0.09 +- 0.06 (stat) +- 0.03(sys). A significant transverse polarization (in the direction orthogonal to the Lambda production plane) has been observed for the first time in a neutrino experiment: Py = -0.22 +- 0.03 (stat) +- 0.01 (sys). The dependence of the absolute value of Py on the Lambda transverse momentum with respect to the hadronic jet direction is in qualitative agreement with the results from unpolarized hadron-hadron experiments. The polarization vector of Lambda-bar hyperons measured for the first time in neutrino interactions is found to be consistent with zero.
2208.01240
Hyun-Chul Kim
June-Young Kim, Bao-Dong Sun, Dongyan Fu, and Hyun-Chul Kim
Mechanical structure of a spin-1 particle
28 pages and 9 figures
null
10.1103/PhysRevD.107.054007
INHA-NTG-06/2022
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate the mechanical structure of a spin-1 particle. Introducing three different frameworks, i.e., the three-dimensional (3D) Breit frame, the two-dimensional (2D) Breit frame, and the 2D infinite momentum frame (equivalently the two-dimensional Drell-Yan frame), we scrutinize the 2D and 3D energy-momentum tensor (EMT) distributions in these frames. We first derive the EMT distributions in the 2D Breit frame by performing the Abel transformation. The mass distribution in the 2D Breit frame contains an additional monopole contribution induced geometrically. The pressure distribution in the 2D Breit frame also gets an induced monopole structure. When the Lorentz boost is carried out, the mass distribution in the 2D infinite-momentum frame acquires the induced dipole term. Similarly, we also have the induced dipole contributions to the pressure and shear-force densities. We visualize the 2D mass distributions when the spin-1 particle is polarized along the $x$- and $z$-axes. We observe that the 2D mass distribution in the infinite momentum frame exhibit clearly the induced dipole structure when the spin-1 particle is polarized along the $x$-axis. We also discuss the strong force fields inside a polarized spin-1 particle.
[ { "created": "Tue, 2 Aug 2022 04:15:44 GMT", "version": "v1" } ]
2023-03-15
[ [ "Kim", "June-Young", "" ], [ "Sun", "Bao-Dong", "" ], [ "Fu", "Dongyan", "" ], [ "Kim", "Hyun-Chul", "" ] ]
We investigate the mechanical structure of a spin-1 particle. Introducing three different frameworks, i.e., the three-dimensional (3D) Breit frame, the two-dimensional (2D) Breit frame, and the 2D infinite momentum frame (equivalently the two-dimensional Drell-Yan frame), we scrutinize the 2D and 3D energy-momentum tensor (EMT) distributions in these frames. We first derive the EMT distributions in the 2D Breit frame by performing the Abel transformation. The mass distribution in the 2D Breit frame contains an additional monopole contribution induced geometrically. The pressure distribution in the 2D Breit frame also gets an induced monopole structure. When the Lorentz boost is carried out, the mass distribution in the 2D infinite-momentum frame acquires the induced dipole term. Similarly, we also have the induced dipole contributions to the pressure and shear-force densities. We visualize the 2D mass distributions when the spin-1 particle is polarized along the $x$- and $z$-axes. We observe that the 2D mass distribution in the infinite momentum frame exhibit clearly the induced dipole structure when the spin-1 particle is polarized along the $x$-axis. We also discuss the strong force fields inside a polarized spin-1 particle.
1503.03382
Sebastian Wild
Alejandro Ibarra, Sebastian Wild
Dirac dark matter with a charged mediator: a comprehensive one-loop analysis of the direct detection phenomenology
20 pages, 5 figures. Matches published version
null
10.1088/1475-7516/2015/05/047
null
hep-ph astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We analyze the direct detection signals of a toy model consisting of a Dirac dark matter particle which couples to one Standard Model fermion via a scalar mediator. For all scenarios, the dark matter particle scatters off nucleons via one loop-induced electromagnetic and electroweak moments, as well as via the one-loop exchange of a Higgs boson. Besides, and depending on the details of the model, the scattering can also be mediated at tree level via the exchange of the scalar mediator or at one loop via gluon-gluon interactions. We show that, for thermally produced dark matter particles, the current limits from the LUX experiment on these scenarios are remarkably strong, even for dark matter coupling only to leptons. We also discuss future prospects for XENON1T and DARWIN and we argue that multi-ton xenon detectors will be able to probe practically the whole parameter space of the model consistent with thermal production and perturbativity. We also discuss briefly the implications of our results for the dark matter interpretation of the Galactic GeV excess.
[ { "created": "Wed, 11 Mar 2015 15:42:30 GMT", "version": "v1" }, { "created": "Fri, 29 May 2015 07:38:47 GMT", "version": "v2" } ]
2015-06-03
[ [ "Ibarra", "Alejandro", "" ], [ "Wild", "Sebastian", "" ] ]
We analyze the direct detection signals of a toy model consisting of a Dirac dark matter particle which couples to one Standard Model fermion via a scalar mediator. For all scenarios, the dark matter particle scatters off nucleons via one loop-induced electromagnetic and electroweak moments, as well as via the one-loop exchange of a Higgs boson. Besides, and depending on the details of the model, the scattering can also be mediated at tree level via the exchange of the scalar mediator or at one loop via gluon-gluon interactions. We show that, for thermally produced dark matter particles, the current limits from the LUX experiment on these scenarios are remarkably strong, even for dark matter coupling only to leptons. We also discuss future prospects for XENON1T and DARWIN and we argue that multi-ton xenon detectors will be able to probe practically the whole parameter space of the model consistent with thermal production and perturbativity. We also discuss briefly the implications of our results for the dark matter interpretation of the Galactic GeV excess.
hep-ph/0310043
Motoi Endo
Motoi Endo, Masahiro Yamaguchi and Akira Yotsuyanagi
Raising Sfermion Masses by Adding Extra Matter Fields
11 pages, 2 figures
Phys.Lett. B580 (2004) 243-248
10.1016/j.physletb.2003.11.039
null
hep-ph
null
The renormalization group flow of soft supersymmetry breaking masses is sensitive to the field contents of the theory one considers. We point out that the addition of extra vector-like matter fields to the minimal supersymmetric standard model raises the masses of squarks and sleptons relative to those of gauginos. We discuss its phenomenological implications. Besides an obvious effect to the superparticle mass spectrum, we find that radiative corrections from heavier stop loops increase the lightest CP-even Higgs boson mass. We also discuss impact on models with no-scale boundary conditions. It turns out that, unlike the minimal case, staus can become heavier than a B-ino like neutralino, which is cosmologically favored.
[ { "created": "Fri, 3 Oct 2003 07:15:49 GMT", "version": "v1" }, { "created": "Fri, 7 Nov 2003 07:58:38 GMT", "version": "v2" } ]
2015-06-25
[ [ "Endo", "Motoi", "" ], [ "Yamaguchi", "Masahiro", "" ], [ "Yotsuyanagi", "Akira", "" ] ]
The renormalization group flow of soft supersymmetry breaking masses is sensitive to the field contents of the theory one considers. We point out that the addition of extra vector-like matter fields to the minimal supersymmetric standard model raises the masses of squarks and sleptons relative to those of gauginos. We discuss its phenomenological implications. Besides an obvious effect to the superparticle mass spectrum, we find that radiative corrections from heavier stop loops increase the lightest CP-even Higgs boson mass. We also discuss impact on models with no-scale boundary conditions. It turns out that, unlike the minimal case, staus can become heavier than a B-ino like neutralino, which is cosmologically favored.
hep-ph/0005267
Tetsuo Shindou
Takahiro Miura, Tetsuo Shindou, Eiichi Takasugi, Masaki Yoshimura
Renormalization group effect and a democratic-type neutrino mass matrix
LaTeX file,22 pages, 2 postscript figures
Phys.Rev. D63 (2001) 053006
10.1103/PhysRevD.63.053006
OU-HET 347
hep-ph
null
In our previous paper, we proposed the democratic-type neutrino mass matrix which gives interesting predictions, $\theta_{23}=-\frac{\pi}4$, $|\tan \theta_{12}|=\sqrt{2-3\sin^2 \theta_{13}}$ and $\delta=\frac {\pi}2$, where $\theta_{ij}$ is the mixing angle between mass eigenstates $\nu_i$ and $\nu_j$, and $\delta$ is the CP violation angle in the standard parameterization of mixing matrix. In this paper, we examined how predictions behave at $m_Z$ by assuming that they are given at the right-handed neutrino mass scale, $M_R$.
[ { "created": "Fri, 26 May 2000 08:46:52 GMT", "version": "v1" }, { "created": "Wed, 20 Sep 2000 00:41:49 GMT", "version": "v2" }, { "created": "Wed, 22 Nov 2000 07:47:52 GMT", "version": "v3" } ]
2009-10-31
[ [ "Miura", "Takahiro", "" ], [ "Shindou", "Tetsuo", "" ], [ "Takasugi", "Eiichi", "" ], [ "Yoshimura", "Masaki", "" ] ]
In our previous paper, we proposed the democratic-type neutrino mass matrix which gives interesting predictions, $\theta_{23}=-\frac{\pi}4$, $|\tan \theta_{12}|=\sqrt{2-3\sin^2 \theta_{13}}$ and $\delta=\frac {\pi}2$, where $\theta_{ij}$ is the mixing angle between mass eigenstates $\nu_i$ and $\nu_j$, and $\delta$ is the CP violation angle in the standard parameterization of mixing matrix. In this paper, we examined how predictions behave at $m_Z$ by assuming that they are given at the right-handed neutrino mass scale, $M_R$.
0706.1125
Egle Tomasi-Gustafsson
C. Adamu\v{s}\v{c}\'in, G. I. Gakh, E. Tomasi-Gustafsson
Polarization effects in the reaction $e^++e^-\to \rho^+ +\rho^- $ and determination of the $\rho -$ meson form factors in the time--like region
19 pages, 2 figures, to appear in Phys Rev C
Phys.Rev.C75:065202,2007
10.1103/PhysRevC.75.065202
null
hep-ph
null
The electron positron annihilation reaction into four pion production has been studied, through the channel $e^++e^-\to \bar \rho+\rho $. The differential (and total) cross sections and various polarization observables for this reaction have been calculated in terms of the electromagnetic form factors of the corresponding $\gamma^*\rho\rho $ current. The elements of the spin--density matrix of the $\rho -$meson were also calculated. Numerical estimations have been done, with the help of phenomenological form factors obtained in the space--like region of the momentum transfer squared and analytically extended to the time-like region.
[ { "created": "Fri, 8 Jun 2007 07:58:00 GMT", "version": "v1" } ]
2008-12-18
[ [ "Adamuščín", "C.", "" ], [ "Gakh", "G. I.", "" ], [ "Tomasi-Gustafsson", "E.", "" ] ]
The electron positron annihilation reaction into four pion production has been studied, through the channel $e^++e^-\to \bar \rho+\rho $. The differential (and total) cross sections and various polarization observables for this reaction have been calculated in terms of the electromagnetic form factors of the corresponding $\gamma^*\rho\rho $ current. The elements of the spin--density matrix of the $\rho -$meson were also calculated. Numerical estimations have been done, with the help of phenomenological form factors obtained in the space--like region of the momentum transfer squared and analytically extended to the time-like region.
1610.01601
Iftah Galon
Iftah Galon, Arvind Rajaraman, Tim M. P. Tait
$H \rightarrow \tau^+ \tau^- \gamma$ as a Probe of the $\tau$ Magnetic Dipole Moment
13 pages, 3 figures
null
10.1007/JHEP12(2016)111
UCI-HEP-TR-2016-16, MITP/16-104
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Low energy observables involving the Standard Model fermions which are chirality-violating, such as anomalous electromagnetic moments, necessarily involve an insertion of the Higgs in order to maintain $SU(2) \times U(1)$ gauge invariance. As the result, the properties of the Higgs boson measured at the LHC impact our understanding of the associated low-energy quantities. We illustrate this feature with a discussion of the electromagnetic moments of the $\tau$-lepton, as probed by the rare decay $H \rightarrow \tau^+ \tau^- \gamma$. We assess the feasibility of measuring this decay at the LHC, and show that the current bounds from lower energy measurements imply that $13~\rm{TeV}$ running is very likely to improve our understanding of new physics contributing to the anomalous magnetic moment of the tau.
[ { "created": "Wed, 5 Oct 2016 20:00:02 GMT", "version": "v1" } ]
2017-02-01
[ [ "Galon", "Iftah", "" ], [ "Rajaraman", "Arvind", "" ], [ "Tait", "Tim M. P.", "" ] ]
Low energy observables involving the Standard Model fermions which are chirality-violating, such as anomalous electromagnetic moments, necessarily involve an insertion of the Higgs in order to maintain $SU(2) \times U(1)$ gauge invariance. As the result, the properties of the Higgs boson measured at the LHC impact our understanding of the associated low-energy quantities. We illustrate this feature with a discussion of the electromagnetic moments of the $\tau$-lepton, as probed by the rare decay $H \rightarrow \tau^+ \tau^- \gamma$. We assess the feasibility of measuring this decay at the LHC, and show that the current bounds from lower energy measurements imply that $13~\rm{TeV}$ running is very likely to improve our understanding of new physics contributing to the anomalous magnetic moment of the tau.
0808.1845
Robert Thorne S
R. S. Thorne
The Longitudinal Structure Function at HERA
4 pages, 6 figures. To appear in the proceedings of the 16th International Workshop on Deep-Inelastic Scattering and Related Subjects (DIS 2008), London, England, 7-11 April 2008
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
I investigate the theoretical uncertainties on the predictions for the longitudinal structure function. I compare the predictions using fixed-order perturbative QCD, higher twist corrections, small-x resummations and the dipole picture. I compare the various predictions to the recent HERA measurements and examine how the data still to be analysed may discriminate between the approaches.
[ { "created": "Wed, 13 Aug 2008 15:19:22 GMT", "version": "v1" } ]
2008-08-14
[ [ "Thorne", "R. S.", "" ] ]
I investigate the theoretical uncertainties on the predictions for the longitudinal structure function. I compare the predictions using fixed-order perturbative QCD, higher twist corrections, small-x resummations and the dipole picture. I compare the various predictions to the recent HERA measurements and examine how the data still to be analysed may discriminate between the approaches.
0803.0765
Aaron Pierce
Timothy Cohen and Aaron Pierce
Testing a U(1) Solution to the Mu Problem
16+1 pages, 4 figures
Phys.Rev.D78:055012,2008
10.1103/PhysRevD.78.055012
MCTP-08-06
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We discuss the collider phenomenology of TeV Z' gauge bosons related to the absence of a bare mu-term in the superpotential. Decays of the type Z' --> Higgsinos can directly test whether a gauge symmetry is responsible for forbidding the Higgsino mass. Decays to multi-lepton final states may allow these signatures to be observed at the Large Hadron Collider. We comment on whether it will be possible to state definitively that the mu-term is forbidden via a gauge symmetry.
[ { "created": "Thu, 6 Mar 2008 14:13:53 GMT", "version": "v1" } ]
2009-01-09
[ [ "Cohen", "Timothy", "" ], [ "Pierce", "Aaron", "" ] ]
We discuss the collider phenomenology of TeV Z' gauge bosons related to the absence of a bare mu-term in the superpotential. Decays of the type Z' --> Higgsinos can directly test whether a gauge symmetry is responsible for forbidding the Higgsino mass. Decays to multi-lepton final states may allow these signatures to be observed at the Large Hadron Collider. We comment on whether it will be possible to state definitively that the mu-term is forbidden via a gauge symmetry.
0806.0499
Yury Bystritskiy
A. I. Ahmadov, M. V. Galynskii, Yu. M. Bystritskiy, E. A. Kuraev, M. G. Shatnev
QED peripheral mechanism of pair production at colliders
25 pages, 5 figures
Phys.Rev.D78:074015,2008
10.1103/PhysRevD.78.074015
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Cross section of the processes of neutral pion production as well as pairs of charged fermions and bosons in peripherical interaction of leptons, photons are calculated in main logarithmical approximation. We investigate the phase volumes and differential cross sections. The differential cross section of few neutral pions and a few pairs production are written down explicitly. Considering the academic problem of summation on the number of pairs for the case of massless particles we reproduce the known results obtained in seventies of last century. The possibility to construct the generator for Monte-Carlo modeling of this processes basing of this results are discussed.
[ { "created": "Tue, 3 Jun 2008 11:28:43 GMT", "version": "v1" } ]
2008-11-26
[ [ "Ahmadov", "A. I.", "" ], [ "Galynskii", "M. V.", "" ], [ "Bystritskiy", "Yu. M.", "" ], [ "Kuraev", "E. A.", "" ], [ "Shatnev", "M. G.", "" ] ]
Cross section of the processes of neutral pion production as well as pairs of charged fermions and bosons in peripherical interaction of leptons, photons are calculated in main logarithmical approximation. We investigate the phase volumes and differential cross sections. The differential cross section of few neutral pions and a few pairs production are written down explicitly. Considering the academic problem of summation on the number of pairs for the case of massless particles we reproduce the known results obtained in seventies of last century. The possibility to construct the generator for Monte-Carlo modeling of this processes basing of this results are discussed.
1607.05556
Debasish Borah
Debasish Borah
Non-zero $\theta_{13}$ with Unbroken $\mu-\tau$ Symmetry of the Active Neutrino Mass Matrix in the Presence of a Light Sterile Neutrino
30 pages, 8 figures, to appear in Phys. Rev. D
Phys. Rev. D 95, 035016 (2017)
10.1103/PhysRevD.95.035016
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We revisit the possibility of generating non-zero reactor mixing angle in a scenario where there is a sterile neutrino at the eV scale apart from the usual three sub-eV scale active neutrinos. We show that the $3\times3$ active neutrino mass matrix can possess a $\mu-\tau$ symmetry and can still be consistent with non-zero value of the reactor mixing angle $\theta_{13}$, if this $\mu-\tau$ symmetry is broken in the sterile neutrino sector. We first propose a simple model based on the discrete flavour symmetry $A_4 \times Z_3 \times Z^{\prime}_3$ to realise such a scenario and then numerically evaluate the complete $3+1$ neutrino parameter space that allows such a possibility. We show that, such a possibility of generating non-zero $\theta_{13}$ can in general, remain valid even if the present $3+1$ neutrino global fit data get ruled out by future experiments. We also discuss the possible implications at neutrinoless double beta decay $(0\nu \beta \beta)$ experiments in view of the latest results from KamLAND-Zen experiment.
[ { "created": "Tue, 19 Jul 2016 12:51:06 GMT", "version": "v1" }, { "created": "Tue, 31 Jan 2017 04:44:26 GMT", "version": "v2" } ]
2017-02-22
[ [ "Borah", "Debasish", "" ] ]
We revisit the possibility of generating non-zero reactor mixing angle in a scenario where there is a sterile neutrino at the eV scale apart from the usual three sub-eV scale active neutrinos. We show that the $3\times3$ active neutrino mass matrix can possess a $\mu-\tau$ symmetry and can still be consistent with non-zero value of the reactor mixing angle $\theta_{13}$, if this $\mu-\tau$ symmetry is broken in the sterile neutrino sector. We first propose a simple model based on the discrete flavour symmetry $A_4 \times Z_3 \times Z^{\prime}_3$ to realise such a scenario and then numerically evaluate the complete $3+1$ neutrino parameter space that allows such a possibility. We show that, such a possibility of generating non-zero $\theta_{13}$ can in general, remain valid even if the present $3+1$ neutrino global fit data get ruled out by future experiments. We also discuss the possible implications at neutrinoless double beta decay $(0\nu \beta \beta)$ experiments in view of the latest results from KamLAND-Zen experiment.
hep-ph/0212257
Erasmo Ferreira
H. G. Dosch and E. Ferreira
Nonperturbative QCD treatment of $J/\psi$ photoproduction
24 pages, 10 figures, 4 tables
Eur.Phys.J.C29:45-58,2003
10.1140/epjc/s2003-01215-4
null
hep-ph
null
We present a nonperturbative QCD calculation of elastic $J/\psi$ meson production in photon-proton scattering at high energies. Using light cone wave functions of the photon and vector mesons, and the framework of the model of the stochastic QCD vacuum, we calculate the differential and integrated elastic cross sections for $\gamma p \goto J/\psi p $ . With an energy dependence following the two-pomeron model we are able to give a consistent description of the integrated cross sections and the differential cross sections at low $|t|$ in the range from 20 GeV up to the highest HERA energies. We discuss different approaches to introduce saturation and find no specific effects up to energies presently available. We also calculate and compare to experiments the cross section for $\upsilon$ photoproduction.
[ { "created": "Wed, 18 Dec 2002 01:15:38 GMT", "version": "v1" } ]
2009-01-07
[ [ "Dosch", "H. G.", "" ], [ "Ferreira", "E.", "" ] ]
We present a nonperturbative QCD calculation of elastic $J/\psi$ meson production in photon-proton scattering at high energies. Using light cone wave functions of the photon and vector mesons, and the framework of the model of the stochastic QCD vacuum, we calculate the differential and integrated elastic cross sections for $\gamma p \goto J/\psi p $ . With an energy dependence following the two-pomeron model we are able to give a consistent description of the integrated cross sections and the differential cross sections at low $|t|$ in the range from 20 GeV up to the highest HERA energies. We discuss different approaches to introduce saturation and find no specific effects up to energies presently available. We also calculate and compare to experiments the cross section for $\upsilon$ photoproduction.
hep-ph/9907291
Ritva Kinnunen
R. Kinnunen, D. Denegri
H(SUSY)->tau+tau->hadron+hadron channel, its advantages and potential instrumental drawbacks
null
null
null
CMS NOTE 1999/037
hep-ph
null
We present a first study of the channel H, A -> tau+tau -> h+ + h- + X in CMS at high m(A) values where no triggering difficulties are expected with QCD jets. At present the tau selection is based solely on the presence of a hard isolated track in the "tau" jet, but further refinements based on calorimeter collimation or impact parameter selections are obviously possible. The main irreducible background in these conditions is due to QCD jets with hard fragmentations. A large reduction of this background and improvement in the expected signal to background ratio is provided by Etmiss cuts. The expected high-mass reach in the m(A) tan(beta) parameter space for 3 x 10**4pb**-1 is shown. This H -> tau+tau channel provides the highest mass reach and the best mass resolution when compared to tau,tau -> lepton+hadron + Xand tau,tau -> electton + muon + X final states. To the extent that with further calorimetric and impact parameter based selection criteria the QCD background can be kept under control, i.e. below the irreducible Z,gamma* -> tau+tau background, we should strive to have a first level trigger allowing to explore the mass range down to ~ 150 - 200 GeV.
[ { "created": "Fri, 9 Jul 1999 16:22:18 GMT", "version": "v1" } ]
2007-05-23
[ [ "Kinnunen", "R.", "" ], [ "Denegri", "D.", "" ] ]
We present a first study of the channel H, A -> tau+tau -> h+ + h- + X in CMS at high m(A) values where no triggering difficulties are expected with QCD jets. At present the tau selection is based solely on the presence of a hard isolated track in the "tau" jet, but further refinements based on calorimeter collimation or impact parameter selections are obviously possible. The main irreducible background in these conditions is due to QCD jets with hard fragmentations. A large reduction of this background and improvement in the expected signal to background ratio is provided by Etmiss cuts. The expected high-mass reach in the m(A) tan(beta) parameter space for 3 x 10**4pb**-1 is shown. This H -> tau+tau channel provides the highest mass reach and the best mass resolution when compared to tau,tau -> lepton+hadron + Xand tau,tau -> electton + muon + X final states. To the extent that with further calorimetric and impact parameter based selection criteria the QCD background can be kept under control, i.e. below the irreducible Z,gamma* -> tau+tau background, we should strive to have a first level trigger allowing to explore the mass range down to ~ 150 - 200 GeV.
hep-ph/0401242
Athar Husain
H. Athar
Atmospheric and galactic tau neutrinos
8 pages, 4 figures, invited talk given at CosPA 2003, 13-15 Nov, 2003, Taipei, Taiwan
Mod.Phys.Lett. A19 (2004) 1171-1178
10.1142/S0217732304014525
null
hep-ph astro-ph
null
Neutrinos with energy greater than GeV are copiously produced in the p(A,p) interactions occurring in the earth atmosphere and in our galactic plane. A comparison of the tau and mu neutrino flux in the presence of neutrino oscillations from these two astrophysical sites is presented. It is pointed out that the galactic plane tau neutrino flux dominates over the downward going atmospheric tau neutrino flux at much lower energy value than that for the dominance of the mu neutrino flux from these two sites. Future prospects for possible observations of galactic tau neutrino flux are also briefly mentioned.
[ { "created": "Fri, 30 Jan 2004 07:08:32 GMT", "version": "v1" } ]
2009-11-10
[ [ "Athar", "H.", "" ] ]
Neutrinos with energy greater than GeV are copiously produced in the p(A,p) interactions occurring in the earth atmosphere and in our galactic plane. A comparison of the tau and mu neutrino flux in the presence of neutrino oscillations from these two astrophysical sites is presented. It is pointed out that the galactic plane tau neutrino flux dominates over the downward going atmospheric tau neutrino flux at much lower energy value than that for the dominance of the mu neutrino flux from these two sites. Future prospects for possible observations of galactic tau neutrino flux are also briefly mentioned.
hep-ph/0507085
Simone Pacetti
R. Baldini, C. Bini, P. Gauzzi, M. Mirazita, M. Negrini, S. Pacetti
A description of the ratio between electric and magnetic proton form factors by using space-like, time-like data and dispersion relations
12 pages, 7 Encapsulated Postscript figures, uses epsfig, rotating, exscale, amsmath, cite, latexsym, graphics, color packages, added references
Eur.Phys.J.C46:421-428,2006
10.1140/epjc/s2006-02499-4
null
hep-ph
null
We use the available information on the ratio between the electric and magnetic proton form factors coming from recently published space-like data and from the few available time-like data. We apply a dispersive procedure on these data to evaluate the behaviour of this ratio, as a complex function, for all values of q^2.
[ { "created": "Thu, 7 Jul 2005 11:55:53 GMT", "version": "v1" }, { "created": "Mon, 11 Jul 2005 13:50:44 GMT", "version": "v2" } ]
2009-01-07
[ [ "Baldini", "R.", "" ], [ "Bini", "C.", "" ], [ "Gauzzi", "P.", "" ], [ "Mirazita", "M.", "" ], [ "Negrini", "M.", "" ], [ "Pacetti", "S.", "" ] ]
We use the available information on the ratio between the electric and magnetic proton form factors coming from recently published space-like data and from the few available time-like data. We apply a dispersive procedure on these data to evaluate the behaviour of this ratio, as a complex function, for all values of q^2.
hep-ph/9704343
Alexander Belyaev
A.S.Belyaev, A.V.Gladyshev
Could we learn more about HERA high Q^2 anomaly from LEP200 and TEVATRON ?
7 pages, LaTeX, 9 figures included
null
null
null
hep-ph
null
The excess of high Q^2 events at HERA has been the subject of recent extensive studies in the framework of several models related to new physics. Here, we would like to concentrate on the most promising, from our point of view, model describing HERA anomaly. We investigate HERA events within the R-parity broken SUSY model and check its relation to LEP and TEVATRON colliders. This study shows that if a squark resonance really takes place at HERA, supersymmetry with broken R-parity can be revealed at either LEP200 or TEVATRON.
[ { "created": "Thu, 17 Apr 1997 08:01:35 GMT", "version": "v1" }, { "created": "Sat, 19 Apr 1997 11:43:12 GMT", "version": "v2" } ]
2008-02-03
[ [ "Belyaev", "A. S.", "" ], [ "Gladyshev", "A. V.", "" ] ]
The excess of high Q^2 events at HERA has been the subject of recent extensive studies in the framework of several models related to new physics. Here, we would like to concentrate on the most promising, from our point of view, model describing HERA anomaly. We investigate HERA events within the R-parity broken SUSY model and check its relation to LEP and TEVATRON colliders. This study shows that if a squark resonance really takes place at HERA, supersymmetry with broken R-parity can be revealed at either LEP200 or TEVATRON.
hep-ph/0407256
Neil Russell
Neil Russell
Testing Relativity with Orbiting Oscillators
11 pages, invited talk at HYPER symposium "Fundamental Physics and Applications of Cold Atoms in Space," Centre National d'Etudes Spatiales, Paris, France, 4-6 November 2002
null
10.1023/B:GERG.0000046187.55942.fa
null
hep-ph
null
Clock-comparison experiments using a satellite platform can give Planck-scale sensitivity to many parameters for Lorentz and CPT violation that are difficult to measure on Earth. A discussion of the theoretical framework for such tests is given, with emphasis on comparisons of output frequencies of atomic clocks and of electromagnetic cavity oscillators.
[ { "created": "Wed, 21 Jul 2004 19:27:51 GMT", "version": "v1" } ]
2009-11-10
[ [ "Russell", "Neil", "" ] ]
Clock-comparison experiments using a satellite platform can give Planck-scale sensitivity to many parameters for Lorentz and CPT violation that are difficult to measure on Earth. A discussion of the theoretical framework for such tests is given, with emphasis on comparisons of output frequencies of atomic clocks and of electromagnetic cavity oscillators.
hep-ph/9401312
null
N.N. Nikolaev and B.G. Zakharov (IKP(Theorie), KFA J\"ulich and L. D. Landau Institute for Theoretical Physics, Moscow)
BFKL evolution and universal structure function at very small $x$
14 pages, 3 figures on request from kph154@zam001.zam.kfa-juelich.de
Phys.Lett.B327:157-165,1994
10.1016/0370-2693(94)91544-X
Juelich preprint KFA-IKP(TH)-1994-5
hep-ph
null
The Balitskii-Fadin-Kuraev-Lipatov (BFKL) and the Gribov-Lipatov- Dokshitzer-Altarelli-Parisi (GLDAP) evolution equations for the diffractive deep inelastic scattering at ${1\over x} \gg 1$ are shown to have a common solution in the weak coupling limit: $F_{2}(x,Q^{2})\propto [\alpha_{S}(Q^{2})]^{-\gamma} \left({1\over x}\right)^{\Delta_{\Pom}}$. The exponent $\gamma$ and the pomeron intercept $\Delta_{\Pom}$ are related by $\gamma\Delta_{\Pom}={4\over 3}$ for the $N_{f}=3$ active flavors. The existence of this solution implies that there is no real clash between the BFKL and GLDAP descriptions at very small $x$. We present derivation of this solution in the framework of our generalized BFKL equation for the dipole cross section, discuss conditions for the onset of the universal scaling violations and analyse the pattern of transition from the conventional Double-Leading-Logarithm approximation for the GLDAP evolution to the BFKL evolution at large ${1\over x}$.
[ { "created": "Mon, 24 Jan 1994 12:05:48 GMT", "version": "v1" } ]
2016-08-14
[ [ "Nikolaev", "N. N.", "", "IKP" ], [ "Zakharov", "B. G.", "", "IKP" ] ]
The Balitskii-Fadin-Kuraev-Lipatov (BFKL) and the Gribov-Lipatov- Dokshitzer-Altarelli-Parisi (GLDAP) evolution equations for the diffractive deep inelastic scattering at ${1\over x} \gg 1$ are shown to have a common solution in the weak coupling limit: $F_{2}(x,Q^{2})\propto [\alpha_{S}(Q^{2})]^{-\gamma} \left({1\over x}\right)^{\Delta_{\Pom}}$. The exponent $\gamma$ and the pomeron intercept $\Delta_{\Pom}$ are related by $\gamma\Delta_{\Pom}={4\over 3}$ for the $N_{f}=3$ active flavors. The existence of this solution implies that there is no real clash between the BFKL and GLDAP descriptions at very small $x$. We present derivation of this solution in the framework of our generalized BFKL equation for the dipole cross section, discuss conditions for the onset of the universal scaling violations and analyse the pattern of transition from the conventional Double-Leading-Logarithm approximation for the GLDAP evolution to the BFKL evolution at large ${1\over x}$.
1805.10566
Vladimir Dzhunushaliev
Vladimir Dzhunushaliev and Vladimir Folomeev
Energy spectrum and the mass gap from nonperturbative quantization \`a la Heisenberg
19 pages, 19 figures
null
null
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Using approximate methods of nonperturbative quantization \`a la Heisenberg and taking into account the interaction of gauge fields with quarks, we find regular solutions describing the following configurations: (i) a spinball consisting of two virtual quarks with opposite spins; (ii) a quantum monopole; (iii) a spinball-plus-quantum-monopole system; and (iv) a spinball-plus-quantum-dyon system. A comparison with quasi-particles obtained by lattice and phenomenological analytical calculations is carried out. All these objects (except the spinball) are embedded in a bag created by the quantum coset condensate consisting of the SU(3)/(SU(2)~$\times$~U(1)) gauge fields. The existence of these objects is due to the Meissner effect, which implies that the SU(2)~$\times$~U(1) gauge fields are expelled from the condensate. The physical interpretation of these solutions is proposed in two different forms: (i) an approximate glueball model; and (ii) quantum fluctuations in the coset condensate of the nonperturbative vacuum or in a quark-gluon plasma. For the spinball and the spinball-plus-quantum-monopole configuration, we obtain energy spectra, in which mass gaps are present. The process of deconfinement is discussed qualitatively. It is shown that the quantum chromodynamics constant $\Lambda_{\text{QCD}}$ appears in the nonperturbative quantization \`a la Heisenberg as some constant controlling the correlation length of quantum fields in a spacelike direction.
[ { "created": "Sun, 27 May 2018 02:11:15 GMT", "version": "v1" }, { "created": "Mon, 6 Aug 2018 10:12:59 GMT", "version": "v2" } ]
2018-08-07
[ [ "Dzhunushaliev", "Vladimir", "" ], [ "Folomeev", "Vladimir", "" ] ]
Using approximate methods of nonperturbative quantization \`a la Heisenberg and taking into account the interaction of gauge fields with quarks, we find regular solutions describing the following configurations: (i) a spinball consisting of two virtual quarks with opposite spins; (ii) a quantum monopole; (iii) a spinball-plus-quantum-monopole system; and (iv) a spinball-plus-quantum-dyon system. A comparison with quasi-particles obtained by lattice and phenomenological analytical calculations is carried out. All these objects (except the spinball) are embedded in a bag created by the quantum coset condensate consisting of the SU(3)/(SU(2)~$\times$~U(1)) gauge fields. The existence of these objects is due to the Meissner effect, which implies that the SU(2)~$\times$~U(1) gauge fields are expelled from the condensate. The physical interpretation of these solutions is proposed in two different forms: (i) an approximate glueball model; and (ii) quantum fluctuations in the coset condensate of the nonperturbative vacuum or in a quark-gluon plasma. For the spinball and the spinball-plus-quantum-monopole configuration, we obtain energy spectra, in which mass gaps are present. The process of deconfinement is discussed qualitatively. It is shown that the quantum chromodynamics constant $\Lambda_{\text{QCD}}$ appears in the nonperturbative quantization \`a la Heisenberg as some constant controlling the correlation length of quantum fields in a spacelike direction.
hep-ph/9905513
Johannes Bluemlein
J. Bl\"umlein, V. Ravindran, and W.L. van Neerven
Relations among Higher Order QCD corrections
Contribution to the Proceedings of the 7th International Workshop on Deep Inelastic Scattering and QCD, DIS99, DESY-Zeuthen, April 1999; Nucl. Phys. B (Proc. Suppl.)
Nucl.Phys.Proc.Suppl. 79 (1999) 169-172
10.1016/S0920-5632(99)00665-9
null
hep-ph
null
We study the scheme transformation of next to leading order QCD corrections to various processes. An interesting relation by Drell, Levy and Yan (DLY) among space like and time like processes is studied carefully in the next to leading order level. We construct factorisation scheme invariants and show that they are DLY-invariant.
[ { "created": "Thu, 27 May 1999 20:19:08 GMT", "version": "v1" } ]
2009-10-31
[ [ "Blümlein", "J.", "" ], [ "Ravindran", "V.", "" ], [ "van Neerven", "W. L.", "" ] ]
We study the scheme transformation of next to leading order QCD corrections to various processes. An interesting relation by Drell, Levy and Yan (DLY) among space like and time like processes is studied carefully in the next to leading order level. We construct factorisation scheme invariants and show that they are DLY-invariant.
0903.0257
Akaki Rusetsky
J. Gasser (Bern U.), V.E. Lyubovitskij (Tuebingen U.), A. Rusetsky (Bonn U., HISKP)
Hadronic Atoms
Commissioned article for Ann. Rev. Nucl. Part. Sci., 34 pages, 5 figures, 3 references added
Ann.Rev.Nucl.Part.Sci.59:169-190,2009
10.1146/annurev.nucl.010909.083806
HISKP-TH-08/20
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We review the theory of hadronic atoms in QCD+QED. The non-relativistic effective Lagrangian approach, used to describe this type of bound states, is illustrated with the case of pi+pi- atoms. In addition, we discuss the evaluation of isospin-breaking corrections to hadronic atom observables by invoking chiral perturbation theory.
[ { "created": "Mon, 2 Mar 2009 13:16:29 GMT", "version": "v1" }, { "created": "Thu, 9 Apr 2009 12:24:37 GMT", "version": "v2" } ]
2009-12-15
[ [ "Gasser", "J.", "", "Bern U." ], [ "Lyubovitskij", "V. E.", "", "Tuebingen U." ], [ "Rusetsky", "A.", "", "Bonn U., HISKP" ] ]
We review the theory of hadronic atoms in QCD+QED. The non-relativistic effective Lagrangian approach, used to describe this type of bound states, is illustrated with the case of pi+pi- atoms. In addition, we discuss the evaluation of isospin-breaking corrections to hadronic atom observables by invoking chiral perturbation theory.
1411.1892
Yilei Tang
Yi-Lei Tang
One Right-handed Neutrino to Generate Complete Neutrino Mass Spectrum in the Framework of NMSSM
20 pages, 7 figures
Nucl. Phys. B 890, 263 2015
10.1016/j.nuclphysb.2014.11.012
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The see-saw mechanism is usually applied to explain the lightness of neutrinos. The traditional see-saw mechanism introduces at least two right-handed neutrinos for the realistic neutrino spectrum. In the case of supersymmetry, loop corrections can also contribute to neutrino masses, which lead to the possibility to generate the neutrino spectrum by introducing just one right-handed neutrino. To be realistic, MSSM suffers from the mu problem and other phenomenological difficulties, so we extend NMSSM (the MSSM with a singlet S) by introducing one single right-handed neutrino superfield (N) and relevant phenomenology is discussed
[ { "created": "Fri, 7 Nov 2014 12:05:43 GMT", "version": "v1" }, { "created": "Fri, 28 Nov 2014 07:13:46 GMT", "version": "v2" } ]
2014-12-01
[ [ "Tang", "Yi-Lei", "" ] ]
The see-saw mechanism is usually applied to explain the lightness of neutrinos. The traditional see-saw mechanism introduces at least two right-handed neutrinos for the realistic neutrino spectrum. In the case of supersymmetry, loop corrections can also contribute to neutrino masses, which lead to the possibility to generate the neutrino spectrum by introducing just one right-handed neutrino. To be realistic, MSSM suffers from the mu problem and other phenomenological difficulties, so we extend NMSSM (the MSSM with a singlet S) by introducing one single right-handed neutrino superfield (N) and relevant phenomenology is discussed
1109.2188
Mina Ketan Parida
R. N. Mohapatra (Maryland U., USA), Mina K. Parida (HRI, Allahabad)
Type II Seesaw Dominance in Non-supersymmetric and Split Susy SO(10) and Proton Life Time
7 pages LaTeX, 3 figures, related areas: hep-ex, hep-th, astro-ph; Reference added, typo corrected, version to appear in Physical Review D
Phys. Rev. D84, 095021 (2011)
10.1103/PhysRevD.84.095021
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Recently type II seesaw dominance in a supersymmetric SO(10) framework has been found useful in explaining large solar and atmospheric mixing angles as well as larger values of $theta_{13}$ while unifying quark and lepton masses. An important question in these models is whether there exists consistency between coupling unification and type II seesaw dominance. Scenarios where this consistency can be demonstrated have been given in a SUSY framework. In this paper we give examples where type II dominance occurs in SO(10) models without supersymmetry but with additional TeV scale particles and also in models with split-supersummetry. Grand unification is realized in a two-step process via breaking of SO(10) to SU(5) and then to a TeV scale standard model supplemented by extra fields and an SU(5) Higgs multiplet ${15}_H$ at a scale about $10^{12}$ GeV to give type-II seesaw. The predictions for proton lifetime in these models are in the range $\tau_p^0 = 2\times 10^{35}$ yrs. to $\tau_p^0 = 6\times 10^{35}$ yrs.. A number of recent numerical fits to GUT-scale fermion masses can be accommodated within this model.
[ { "created": "Sat, 10 Sep 2011 03:03:06 GMT", "version": "v1" }, { "created": "Sun, 25 Sep 2011 06:51:42 GMT", "version": "v2" }, { "created": "Fri, 28 Oct 2011 16:48:25 GMT", "version": "v3" } ]
2013-05-29
[ [ "Mohapatra", "R. N.", "", "Maryland U., USA" ], [ "Parida", "Mina K.", "", "HRI, Allahabad" ] ]
Recently type II seesaw dominance in a supersymmetric SO(10) framework has been found useful in explaining large solar and atmospheric mixing angles as well as larger values of $theta_{13}$ while unifying quark and lepton masses. An important question in these models is whether there exists consistency between coupling unification and type II seesaw dominance. Scenarios where this consistency can be demonstrated have been given in a SUSY framework. In this paper we give examples where type II dominance occurs in SO(10) models without supersymmetry but with additional TeV scale particles and also in models with split-supersummetry. Grand unification is realized in a two-step process via breaking of SO(10) to SU(5) and then to a TeV scale standard model supplemented by extra fields and an SU(5) Higgs multiplet ${15}_H$ at a scale about $10^{12}$ GeV to give type-II seesaw. The predictions for proton lifetime in these models are in the range $\tau_p^0 = 2\times 10^{35}$ yrs. to $\tau_p^0 = 6\times 10^{35}$ yrs.. A number of recent numerical fits to GUT-scale fermion masses can be accommodated within this model.
2205.01169
Alexandre Deur
A. Deur, V. Burkert, J.P. Chen and W. Korsch
Experimental determination of the QCD effective charge $\alpha_{g_1}(Q)$
16 pages, 1 figure. Published version. Prepared for the Special Issue of PARTICLES: "Strong Interactions in the Standard Model: Massless Bosons to Compact Stars"
Particles 5(2), 171 (2022)
10.3390/particles5020015
JLAB-PHY-22-3609
hep-ph hep-ex nucl-ex
http://creativecommons.org/licenses/by/4.0/
The QCD effective charge $\alpha_{g_1}(Q)$ is an observable that characterizes the magnitude of the strong interaction. At high momentum $Q$, it coincides with the QCD running coupling $\alpha_{\rm s}(Q)$. At low $Q$, it offers a nonperturbative definition of the running coupling. We have extracted $\alpha_{g_1}(Q)$ from measurements carried out at Jefferson Lab that span the very low to moderately high $Q$ domain, $0.14 \leq Q \leq 2.18$ GeV. The precision of the new results is much improved over the previous extractions and the reach in $Q$ at the lower end is significantly expanded. The data show that $\alpha_{g_1}(Q)$ becomes $Q$-independent at very low $Q$. They compare well with two recent predictions of the QCD effective charge based on Dyson-Schwinger equations and on the AdS/CFT duality.
[ { "created": "Mon, 2 May 2022 19:25:13 GMT", "version": "v1" }, { "created": "Mon, 30 May 2022 11:22:45 GMT", "version": "v2" } ]
2022-07-11
[ [ "Deur", "A.", "" ], [ "Burkert", "V.", "" ], [ "Chen", "J. P.", "" ], [ "Korsch", "W.", "" ] ]
The QCD effective charge $\alpha_{g_1}(Q)$ is an observable that characterizes the magnitude of the strong interaction. At high momentum $Q$, it coincides with the QCD running coupling $\alpha_{\rm s}(Q)$. At low $Q$, it offers a nonperturbative definition of the running coupling. We have extracted $\alpha_{g_1}(Q)$ from measurements carried out at Jefferson Lab that span the very low to moderately high $Q$ domain, $0.14 \leq Q \leq 2.18$ GeV. The precision of the new results is much improved over the previous extractions and the reach in $Q$ at the lower end is significantly expanded. The data show that $\alpha_{g_1}(Q)$ becomes $Q$-independent at very low $Q$. They compare well with two recent predictions of the QCD effective charge based on Dyson-Schwinger equations and on the AdS/CFT duality.
2106.00276
Silvia Ferrario Ravasio
Silvia Ferrario Ravasio
Infrared Renormalons in Collider Processes
Contribution to EPJ ST "Renormalons and Hyperasymptotics in QCD"
null
10.1140/epjs/s11734-021-00254-2
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Precise theoretical predictions are a key ingredient for an accurate determination of the structure of the Langrangian of particle physics, including its free parameters, which summarizes our understanding of the fundamental interactions among particles. Furthermore, due to the absence of clear new-physics signals, precise theoretical calculations are required in order to pin down possible subtle deviations from the Standard Model predictions. The error associated with such calculations must be scrutinized, as non-perturbative power corrections, dubbed infrared renormalons, can limit the ultimate precision of truncated perturbative expansions in quantum chromodynamics. In this review we focus on linear power corrections that can arise in certain kinematic distributions relevant for collider phenomenology where an operator product expansion is missing, e.g. those obtained from the top-quark decay products, shape observables and the transverse momentum of massive gauge bosons. Only the last one is found to be free from such corrections, while the mass of the system comprising the top decay products has a larger power correction if the perturbative expansion is expressed in terms of a short-distance mass instead of the pole mass. A proper modelization of non-perturbative corrections is crucial in the context of shape observables to obtain reliable strong coupling constant extractions.
[ { "created": "Tue, 1 Jun 2021 07:15:33 GMT", "version": "v1" } ]
2021-09-01
[ [ "Ravasio", "Silvia Ferrario", "" ] ]
Precise theoretical predictions are a key ingredient for an accurate determination of the structure of the Langrangian of particle physics, including its free parameters, which summarizes our understanding of the fundamental interactions among particles. Furthermore, due to the absence of clear new-physics signals, precise theoretical calculations are required in order to pin down possible subtle deviations from the Standard Model predictions. The error associated with such calculations must be scrutinized, as non-perturbative power corrections, dubbed infrared renormalons, can limit the ultimate precision of truncated perturbative expansions in quantum chromodynamics. In this review we focus on linear power corrections that can arise in certain kinematic distributions relevant for collider phenomenology where an operator product expansion is missing, e.g. those obtained from the top-quark decay products, shape observables and the transverse momentum of massive gauge bosons. Only the last one is found to be free from such corrections, while the mass of the system comprising the top decay products has a larger power correction if the perturbative expansion is expressed in terms of a short-distance mass instead of the pole mass. A proper modelization of non-perturbative corrections is crucial in the context of shape observables to obtain reliable strong coupling constant extractions.
1504.02334
Wayne W. Repko
Duane A. Dicus, Chung Kao and Wayne W. Repko
Interference effects and the use of Higgs boson pair production to study the Higgs trilinear self coupling
8 pages, 4 figures, additional references,publication version
Phys. Rev. D 92, 093003 (2015)
10.1103/PhysRevD.92.093003
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We show that the dominant channel proposed for the determination of the Higgs boson trilinear coupling, $pp\to HH+X$ via gluon fusion, exhibits an interference structure that is independent of the collider energy for collider energies in the range $8\,{\rm TeV}\leq \sqrt{s}\leq 100\,{\rm TeV}$ and is almost maximally destructive. This insensitivity to the collider energy remains approximately true for a variety of other two Higgs production mechanisms although the magnitude of the interference varies widely.
[ { "created": "Thu, 9 Apr 2015 14:38:15 GMT", "version": "v1" }, { "created": "Wed, 29 Apr 2015 19:56:37 GMT", "version": "v2" }, { "created": "Mon, 26 Oct 2015 18:04:26 GMT", "version": "v3" } ]
2015-11-11
[ [ "Dicus", "Duane A.", "" ], [ "Kao", "Chung", "" ], [ "Repko", "Wayne W.", "" ] ]
We show that the dominant channel proposed for the determination of the Higgs boson trilinear coupling, $pp\to HH+X$ via gluon fusion, exhibits an interference structure that is independent of the collider energy for collider energies in the range $8\,{\rm TeV}\leq \sqrt{s}\leq 100\,{\rm TeV}$ and is almost maximally destructive. This insensitivity to the collider energy remains approximately true for a variety of other two Higgs production mechanisms although the magnitude of the interference varies widely.
hep-ph/0102204
Takeo Moroi
Shinji Komine, Takeo Moroi and Masahiro Yamaguchi
Recent Result from E821 Experiment on Muon g-2 and Unconstrained Minimal Supersymemtric Standard Model
10 pages, 5 figures
Phys.Lett. B506 (2001) 93-98
10.1016/S0370-2693(01)00381-1
TU-611
hep-ph
null
Recently, the E821 experiment at the Brookhaven National Laboratory announced their latest result of their muon g-2 measurement which is about 2.6-\sigma away from the standard model prediction. Taking this result seriously, we examine the possibility to explain this discrepancy by the supersymmetric contribution. Our analysis is performed in the framework of the unconstrained supersymmetric standard model which has free seven parameters relevant to muon g-2. We found that, in the case of large \tan\beta, sparticle masses are allowed to be large in the region where the SUSY contribution to the muon g-2 is large enough, and hence the conventional SUSY search may fail even at the LHC. On the contrary, to explain the discrepancy in the case of small \tan\beta, we found that (i) sleptons and SU(2)_L gauginos should be light, and (ii) negative search for the Higgs boson severely constrains the model in the framework of the mSUGRA and gauge-mediated model.
[ { "created": "Fri, 16 Feb 2001 09:50:53 GMT", "version": "v1" } ]
2009-11-07
[ [ "Komine", "Shinji", "" ], [ "Moroi", "Takeo", "" ], [ "Yamaguchi", "Masahiro", "" ] ]
Recently, the E821 experiment at the Brookhaven National Laboratory announced their latest result of their muon g-2 measurement which is about 2.6-\sigma away from the standard model prediction. Taking this result seriously, we examine the possibility to explain this discrepancy by the supersymmetric contribution. Our analysis is performed in the framework of the unconstrained supersymmetric standard model which has free seven parameters relevant to muon g-2. We found that, in the case of large \tan\beta, sparticle masses are allowed to be large in the region where the SUSY contribution to the muon g-2 is large enough, and hence the conventional SUSY search may fail even at the LHC. On the contrary, to explain the discrepancy in the case of small \tan\beta, we found that (i) sleptons and SU(2)_L gauginos should be light, and (ii) negative search for the Higgs boson severely constrains the model in the framework of the mSUGRA and gauge-mediated model.
1609.02990
Takuya Morozumi
Takuya Morozumi, Keiko I. Nagao, Apriadi Salim Adam, Hiroyuki Takata
Creation and evolution of particle numberasymmetry in an expanding universe
5 pages 1 figure , Submitted to the proceedings of the conference International workshop for "Strong Field Problems in Quantum Theory" (June 6-11, Tomsk Russia 2016.)
null
10.1007/s11182-017-0986-x
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We introduce a model which may generate particle number asymmetry in an expanding Universe. The model includes CP violating and particle number violating interactions. The model consists of a real scalar field and a complex scalar field. Starting with an initial condition specified by a density matrix, we show how the asymmetry is created through the interaction and how it evolves at later time. We compute the asymmetry using non-equilibrium quantum field theory and as a first test of the model, we study how the asymmetry evolves in the flat limit.
[ { "created": "Sat, 10 Sep 2016 02:01:06 GMT", "version": "v1" } ]
2017-04-05
[ [ "Morozumi", "Takuya", "" ], [ "Nagao", "Keiko I.", "" ], [ "Adam", "Apriadi Salim", "" ], [ "Takata", "Hiroyuki", "" ] ]
We introduce a model which may generate particle number asymmetry in an expanding Universe. The model includes CP violating and particle number violating interactions. The model consists of a real scalar field and a complex scalar field. Starting with an initial condition specified by a density matrix, we show how the asymmetry is created through the interaction and how it evolves at later time. We compute the asymmetry using non-equilibrium quantum field theory and as a first test of the model, we study how the asymmetry evolves in the flat limit.
hep-ph/9207253
null
S. Kelley, J. Lopez, D. Nanopoulos, H. Pois, and K. Yuan
New Constraints on Neutralino Dark Matter in the Supersymmetric Standard Model
12 pages plus 6 figures (not included), CERN-TH.6584/92, CTP-TAMU-56/92, UAHEP9212
Phys.Rev.D47:2461-2467,1993
10.1103/PhysRevD.47.2461
null
hep-ph
null
We investigate the prospects for neutralino dark matter within the Supersymmetric Standard Model (SSM) including the constraints from universal soft supersymmetry breaking and radiative breaking of the electroweak symmetry. The latter is enforced by using the one-loop Higgs effective potential which automatically gives the one-loop corrected Higgs boson masses. We perform an exhaustive search of the allowed five-dimensional parameter space and find that the neutralino relic abundance $\Omega_\chi h^2_0$ depends most strongly on the ratio $\xi_0\equiv m_0/m_{1/2}$. For $\xi_0\gg1$ the relic abundance is almost always much too large, whereas for $\xi_0\ll1$ the opposite occurs. For $\xi_0\sim1$ there are wide ranges of the remaining parameters for which $\Omega_\chi\sim1$. We also determine that $m_{\tilde q}\gsim250\GeV$ and $m_{\tilde l}\gsim100\GeV$ are necessary in order to possibly achieve $\Omega_\chi\sim1$. These lower bounds are much weaker than the corresponding ones derived previously when radiative breaking was {\it not} enforced.
[ { "created": "Wed, 22 Jul 1992 19:51:00 GMT", "version": "v1" } ]
2008-11-26
[ [ "Kelley", "S.", "" ], [ "Lopez", "J.", "" ], [ "Nanopoulos", "D.", "" ], [ "Pois", "H.", "" ], [ "Yuan", "K.", "" ] ]
We investigate the prospects for neutralino dark matter within the Supersymmetric Standard Model (SSM) including the constraints from universal soft supersymmetry breaking and radiative breaking of the electroweak symmetry. The latter is enforced by using the one-loop Higgs effective potential which automatically gives the one-loop corrected Higgs boson masses. We perform an exhaustive search of the allowed five-dimensional parameter space and find that the neutralino relic abundance $\Omega_\chi h^2_0$ depends most strongly on the ratio $\xi_0\equiv m_0/m_{1/2}$. For $\xi_0\gg1$ the relic abundance is almost always much too large, whereas for $\xi_0\ll1$ the opposite occurs. For $\xi_0\sim1$ there are wide ranges of the remaining parameters for which $\Omega_\chi\sim1$. We also determine that $m_{\tilde q}\gsim250\GeV$ and $m_{\tilde l}\gsim100\GeV$ are necessary in order to possibly achieve $\Omega_\chi\sim1$. These lower bounds are much weaker than the corresponding ones derived previously when radiative breaking was {\it not} enforced.
1412.5011
Hartmut Abele
Hartmut Abele, Tobias Jenke, Gertrud Konrad
Spectroscopy with cold and ultra-cold neutrons
3 pages, 2 figures, Proceedings of the Fifteenth International Symposium on Capture Gamma-Ray Spectroscopy and Related Topics (CGS15), TU Dresden, August 25 to August 29, 2014
null
null
null
hep-ph gr-qc physics.ins-det
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present two new types of spectroscopy methods for cold and ultra-cold neutrons. The first method, which uses the \RB drift effect to disperse charged particles in a uniformly curved magnetic field, allows to study neutron $\beta$-decay. We aim for a precision on the 10$^{-4}$ level. The second method that we refer to as gravity resonance spectroscopy (GRS) allows to test Newton's gravity law at short distances. At the level of precision we are able to provide constraints on any possible gravity-like interaction. In particular, limits on dark energy chameleon fields are improved by several orders of magnitude.
[ { "created": "Tue, 16 Dec 2014 14:23:35 GMT", "version": "v1" } ]
2014-12-17
[ [ "Abele", "Hartmut", "" ], [ "Jenke", "Tobias", "" ], [ "Konrad", "Gertrud", "" ] ]
We present two new types of spectroscopy methods for cold and ultra-cold neutrons. The first method, which uses the \RB drift effect to disperse charged particles in a uniformly curved magnetic field, allows to study neutron $\beta$-decay. We aim for a precision on the 10$^{-4}$ level. The second method that we refer to as gravity resonance spectroscopy (GRS) allows to test Newton's gravity law at short distances. At the level of precision we are able to provide constraints on any possible gravity-like interaction. In particular, limits on dark energy chameleon fields are improved by several orders of magnitude.
hep-ph/0312148
Alessandro Vicini
Alessandro Vicini
The electric charge at the two-loop level in the Standard Model and the precision measurements of Delta alpha_{had}
Talk given at the workshop SIGHAD03, Pisa, 8-10 October 2003, two references added
null
10.1016/S0920-5632(04)00018-0
null
hep-ph
null
The complete calculation of the 2-loop electroweak corrections to the renormalization of the electric charge in the Standard Model allows to discuss in detail the value of the MSbar effective coupling $\hat e(m_Z)$. We discuss the phenomenological impact of these results in view of the increasing accuracy in the measurements of the cross-section of the reaction e+e- -->hadrons at low energies.
[ { "created": "Thu, 11 Dec 2003 14:52:16 GMT", "version": "v1" }, { "created": "Tue, 16 Dec 2003 13:14:15 GMT", "version": "v2" } ]
2009-11-10
[ [ "Vicini", "Alessandro", "" ] ]
The complete calculation of the 2-loop electroweak corrections to the renormalization of the electric charge in the Standard Model allows to discuss in detail the value of the MSbar effective coupling $\hat e(m_Z)$. We discuss the phenomenological impact of these results in view of the increasing accuracy in the measurements of the cross-section of the reaction e+e- -->hadrons at low energies.
1205.5411
Francesco Hautmann
F. Hautmann
Energy flow observables in hadronic collisions
6 pages, 4 figures. Contribution at MPI@LHC2011
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present recent QCD calculations of energy flow distributions associated with the production of jets at wide rapidity separations in high-energy hadron collisions, and discuss the role of these observables to analyze contributions from parton showering and from multiple parton collisions.
[ { "created": "Thu, 24 May 2012 12:08:42 GMT", "version": "v1" } ]
2012-05-25
[ [ "Hautmann", "F.", "" ] ]
We present recent QCD calculations of energy flow distributions associated with the production of jets at wide rapidity separations in high-energy hadron collisions, and discuss the role of these observables to analyze contributions from parton showering and from multiple parton collisions.
1607.00004
Michele Cicoli
Luis Aparicio, Michele Cicoli, Bhaskar Dutta, Francesco Muia, Fernando Quevedo
Light Higgsino Dark Matter from Non-thermal Cosmology
21 pages, 6 figures; references added and typos corrected
null
null
null
hep-ph astro-ph.CO hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the scenario of higgsino dark matter in the context of a non-standard cosmology with a period of matter-domination prior to Big-Bang nucleosynthesis. Matter-domination changes the dark matter relic abundance if it ends via reheating to a temperature below the higgsino thermal freeze-out temperature. We perform a model independent analysis of the higgsino dark matter production in such scenario. We show that light higgsino-type dark matter is possible for reheating temperatures close to 1 GeV. We study the impact of dark matter indirect detection and collider physics in this context. We show that Fermi-LAT data rules out non-thermal higgsinos with masses below 300 GeV. Future indirect dark matter searches from Fermi-LAT and CTA would be able to cover essentially the full parameter space. Contrary to the thermal case, collider signals from a 100 TeV collider could fully test the non-thermal higgsino. In the second part of the paper we discuss the motivation of such non-thermal cosmology from the perspective of string theory with late-time decaying moduli for both KKLT and LVS moduli stabilization mechanisms. We describe the impact of embedding dark matter higgsino in these scenarios.
[ { "created": "Thu, 30 Jun 2016 20:00:04 GMT", "version": "v1" }, { "created": "Wed, 2 Nov 2016 17:58:04 GMT", "version": "v2" } ]
2016-11-03
[ [ "Aparicio", "Luis", "" ], [ "Cicoli", "Michele", "" ], [ "Dutta", "Bhaskar", "" ], [ "Muia", "Francesco", "" ], [ "Quevedo", "Fernando", "" ] ]
We study the scenario of higgsino dark matter in the context of a non-standard cosmology with a period of matter-domination prior to Big-Bang nucleosynthesis. Matter-domination changes the dark matter relic abundance if it ends via reheating to a temperature below the higgsino thermal freeze-out temperature. We perform a model independent analysis of the higgsino dark matter production in such scenario. We show that light higgsino-type dark matter is possible for reheating temperatures close to 1 GeV. We study the impact of dark matter indirect detection and collider physics in this context. We show that Fermi-LAT data rules out non-thermal higgsinos with masses below 300 GeV. Future indirect dark matter searches from Fermi-LAT and CTA would be able to cover essentially the full parameter space. Contrary to the thermal case, collider signals from a 100 TeV collider could fully test the non-thermal higgsino. In the second part of the paper we discuss the motivation of such non-thermal cosmology from the perspective of string theory with late-time decaying moduli for both KKLT and LVS moduli stabilization mechanisms. We describe the impact of embedding dark matter higgsino in these scenarios.
hep-ph/9311241
My Account
J. Lopez, D. Nanopoulos, A. Zichichi
A Layman's guide to SUSY GUTs
25 pages, Latex, 11 figures (not included), CERN-TH.7077/93, CTP-TAMU-65/93. A complete ps file (1.31MB) with embedded figures is available by request from me@cryptons.tamu.edu
Riv.Nuovo Cim. 17N2 (1994) 1-20
10.1007/BF02724510
null
hep-ph
null
The determination of the most straightforward evidence for the existence of the Superworld requires a guide for non-experts (especially experimental physicists) for them to make their own judgement on the value of such predictions. For this purpose we review the most basic results of Super-Grand unification in a simple and clear way. We focus the attention on two specific models and their predictions. These two models represent an example of a direct comparison between a traditional unified-theory and a string-inspired approach to the solution of the many open problems of the Standard Model. We emphasize that viable models must satisfy {\em all} available experimental constraints and be as simple as theoretically possible. The two well defined supergravity models, $SU(5)$ and $SU(5)\times U(1)$, can be described in terms of only a few parameters (five and three respectively) instead of the more than twenty needed in the MSSM model, \ie, the Minimal Supersymmetric extension of the Standard Model. A case of special interest is the strict no-scale $SU(5)\times U(1)$ supergravity where all predictions depend on only one parameter (plus the top-quark mass). A general consequence of these analyses is that supersymmetric particles can be at the verge of discovery, lurking around the corner at present and near future facilities. This review should help anyone distinguish between well motivated predictions and predictions based on arbitrary choices of parameters in undefined models.
[ { "created": "Mon, 8 Nov 1993 20:14:12 GMT", "version": "v1" } ]
2015-06-25
[ [ "Lopez", "J.", "" ], [ "Nanopoulos", "D.", "" ], [ "Zichichi", "A.", "" ] ]
The determination of the most straightforward evidence for the existence of the Superworld requires a guide for non-experts (especially experimental physicists) for them to make their own judgement on the value of such predictions. For this purpose we review the most basic results of Super-Grand unification in a simple and clear way. We focus the attention on two specific models and their predictions. These two models represent an example of a direct comparison between a traditional unified-theory and a string-inspired approach to the solution of the many open problems of the Standard Model. We emphasize that viable models must satisfy {\em all} available experimental constraints and be as simple as theoretically possible. The two well defined supergravity models, $SU(5)$ and $SU(5)\times U(1)$, can be described in terms of only a few parameters (five and three respectively) instead of the more than twenty needed in the MSSM model, \ie, the Minimal Supersymmetric extension of the Standard Model. A case of special interest is the strict no-scale $SU(5)\times U(1)$ supergravity where all predictions depend on only one parameter (plus the top-quark mass). A general consequence of these analyses is that supersymmetric particles can be at the verge of discovery, lurking around the corner at present and near future facilities. This review should help anyone distinguish between well motivated predictions and predictions based on arbitrary choices of parameters in undefined models.
2203.07056
Sho Iwamoto
Motoi Endo, Koichi Hamaguchi, Sho Iwamoto, Shin-ichi Kawada, Teppei Kitahara, Takeo Moroi, Taikan Suehara
Stau study at the ILC and its implication for the muon g-2 anomaly
19 pages, 5 figures, contribution to Snowmass 2021
null
null
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Once all the sleptons as well as the Bino are observed at the ILC, the Bino contribution to the muon anomalous magnetic dipole moment (muon $g-2$) in supersymmetric (SUSY) models can be reconstructed. Motivated by the recently confirmed muon $g-2$ anomaly, we examine the reconstruction accuracy at the ILC with $\sqrt{s}$ = 500 GeV. For this purpose, measurements of stau parameters are important. We quantitatively study the determination of the mass and mixing parameters of the staus at the ILC. Furthermore, we discuss the implication of the stau study to the reconstruction of the SUSY contribution to the muon $g-2$. At the benchmark point of our choice, we find that the SUSY contribution to the muon $g-2$ can be determined with a precision of $\sim 1\%$ at the ILC.
[ { "created": "Mon, 14 Mar 2022 12:51:56 GMT", "version": "v1" }, { "created": "Mon, 30 May 2022 12:17:25 GMT", "version": "v2" } ]
2022-05-31
[ [ "Endo", "Motoi", "" ], [ "Hamaguchi", "Koichi", "" ], [ "Iwamoto", "Sho", "" ], [ "Kawada", "Shin-ichi", "" ], [ "Kitahara", "Teppei", "" ], [ "Moroi", "Takeo", "" ], [ "Suehara", "Taikan", "" ] ]
Once all the sleptons as well as the Bino are observed at the ILC, the Bino contribution to the muon anomalous magnetic dipole moment (muon $g-2$) in supersymmetric (SUSY) models can be reconstructed. Motivated by the recently confirmed muon $g-2$ anomaly, we examine the reconstruction accuracy at the ILC with $\sqrt{s}$ = 500 GeV. For this purpose, measurements of stau parameters are important. We quantitatively study the determination of the mass and mixing parameters of the staus at the ILC. Furthermore, we discuss the implication of the stau study to the reconstruction of the SUSY contribution to the muon $g-2$. At the benchmark point of our choice, we find that the SUSY contribution to the muon $g-2$ can be determined with a precision of $\sim 1\%$ at the ILC.
hep-ph/0006001
Keum Yong-Yeon
Yong-Yeon Keum and Hsiang-nan Li
Nonleptonic charmless B decays: factorization vs perturbative QCD
18 pages, revtex, aps.style, 5 figures
Phys.Rev.D63:074006,2001
10.1103/PhysRevD.63.074006
NCKU-HEP-00-03, IPAS-HEP-2003, APCTP-00-09
hep-ph
null
We compare the factorization approach, the perturbative QCD approach and the Beneke-Buchalla-Neubert-Sachrajda approach to nonleptonic charmless $B$ meson decays. We discuss their treatments of factorizable, nonfactorizable, and annihilation contributions, infrared-cutoff and scale dependences, and strong phases. It is proposed that measurement of CP asymmetries in two-body $B$ meson decays provides an appropriate test of the these approaches.
[ { "created": "Thu, 1 Jun 2000 05:54:44 GMT", "version": "v1" } ]
2009-08-25
[ [ "Keum", "Yong-Yeon", "" ], [ "Li", "Hsiang-nan", "" ] ]
We compare the factorization approach, the perturbative QCD approach and the Beneke-Buchalla-Neubert-Sachrajda approach to nonleptonic charmless $B$ meson decays. We discuss their treatments of factorizable, nonfactorizable, and annihilation contributions, infrared-cutoff and scale dependences, and strong phases. It is proposed that measurement of CP asymmetries in two-body $B$ meson decays provides an appropriate test of the these approaches.
hep-ph/0104151
Chao-Qiang Geng
Chuan-Hung Chen and C.Q. Geng
The Muon Anomalous Magnetic Moment from a Generic Charged Higgs with SUSY
10 pages, 3 Figures, LaTex file; squark masses discussed, references added
Phys.Lett.B511:77-84,2001
10.1016/S0370-2693(01)00651-7
null
hep-ph
null
We study the contribution of a generic charged Higgs $(H^+)$ to the muon anomalous magnetic moment $a_{\mu}$ with the SUSY soft breaking parameters. We find out that the deviation between the experimental data and the predicted SM value on $a_{\mu}$ can be explained by the two-loop charged Higgs diagrams even with $m_{H^+}\sim 400 GeV$.
[ { "created": "Mon, 16 Apr 2001 15:47:12 GMT", "version": "v1" }, { "created": "Tue, 8 May 2001 03:39:42 GMT", "version": "v2" } ]
2008-11-26
[ [ "Chen", "Chuan-Hung", "" ], [ "Geng", "C. Q.", "" ] ]
We study the contribution of a generic charged Higgs $(H^+)$ to the muon anomalous magnetic moment $a_{\mu}$ with the SUSY soft breaking parameters. We find out that the deviation between the experimental data and the predicted SM value on $a_{\mu}$ can be explained by the two-loop charged Higgs diagrams even with $m_{H^+}\sim 400 GeV$.
hep-ph/9503346
null
J.P. Ma
Gluon Fragmentation into $^3P_J$ Quarkonium
Type-errors in the text and equations are eliminated. Several sentences are added in Sect.4. The file is compressed and uuencoded (E-Mail contact ma@tauon.ph.unimelb.edu.au)
Nucl.Phys.B447:405-424,1995
10.1016/0550-3213(95)00270-3
UM--P-95--23, RECHP--95-9
hep-ph
null
The functions of the gluon fragmentation into $^3P_J$ quarkonium are calculated to order $\alpha_s^2$. With the recent progress in analysing quarkonium systems in QCD we show explicitly how the socalled divergence in the limit of the zero-binding energy, which is related to $P$-wave quarkonia, is treated correctly in the case of fragmentation functions. The obtained fragmentation functions satisfy explicitly at the order of $\alpha_s^2$ the Altarelli-Parisi equation and when $z\rightarrow 0$ they behave as $z^{-1}$ as expected. Some comments on the previous results are made.
[ { "created": "Thu, 16 Mar 1995 04:30:32 GMT", "version": "v1" }, { "created": "Tue, 23 May 1995 02:45:01 GMT", "version": "v2" } ]
2014-11-17
[ [ "Ma", "J. P.", "" ] ]
The functions of the gluon fragmentation into $^3P_J$ quarkonium are calculated to order $\alpha_s^2$. With the recent progress in analysing quarkonium systems in QCD we show explicitly how the socalled divergence in the limit of the zero-binding energy, which is related to $P$-wave quarkonia, is treated correctly in the case of fragmentation functions. The obtained fragmentation functions satisfy explicitly at the order of $\alpha_s^2$ the Altarelli-Parisi equation and when $z\rightarrow 0$ they behave as $z^{-1}$ as expected. Some comments on the previous results are made.
1509.09159
Helmut Eberl Dr.
Helmut Eberl, Vassilis C. Spanos
GravitinoPack and decays of supersymmetric metastable particles
32 pages, 8 figures, 7 tables. The package can be downloaded from http://www.hephy.at/susytools/gravitinopack
null
10.1016/j.cpc.2015.12.027
HEPHY-PUB 959/15
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present the package GravitinoPack that calculates the two- and three-body decays of unstable supersymmetric particles involving the gravitino in the final or initial state. In a previous paper, we already showed results for the gravitino decays into two and three particles. In this paper, we incorporate the processes where an unstable neutralino, stau or stop decays into a gravitino and Standard Model particles. This is the case in gravitino dark matter supersymmetric models, where the gravitino is the lightest SUSY particle. We give instructions for the installation and the use of the package. In the numerical analysis, we discuss various MSSM scenarios. We show that the calculation of all the decay channels and the three-body decay branching ratios is essential for the accurate application of cosmological bounds on these models.
[ { "created": "Wed, 30 Sep 2015 12:47:13 GMT", "version": "v1" } ]
2016-04-20
[ [ "Eberl", "Helmut", "" ], [ "Spanos", "Vassilis C.", "" ] ]
We present the package GravitinoPack that calculates the two- and three-body decays of unstable supersymmetric particles involving the gravitino in the final or initial state. In a previous paper, we already showed results for the gravitino decays into two and three particles. In this paper, we incorporate the processes where an unstable neutralino, stau or stop decays into a gravitino and Standard Model particles. This is the case in gravitino dark matter supersymmetric models, where the gravitino is the lightest SUSY particle. We give instructions for the installation and the use of the package. In the numerical analysis, we discuss various MSSM scenarios. We show that the calculation of all the decay channels and the three-body decay branching ratios is essential for the accurate application of cosmological bounds on these models.
2405.13275
Yajin Zhou
Ya-jin Zhou
Azimuthal angular correlations in lepton pair production in ultra-peripheral heavy ion collisions
1st International Workshop on the physics of Ultra Peripheral Collisions (UPC 2023)
null
null
null
hep-ph
http://creativecommons.org/licenses/by-nc-sa/4.0/
The coherent photons induced by relativistic heavy ions are highly linearly polarized, in close analogy to the linear polarization of gluons in a large nucleus. We proposed to measure the photon polarization through azimuthal asymmetries in dilepton production in ultra-peripheral collisions. Our prediction for the asymmetries were soon confirmed by the STAR experiment with high precision. We refined our analysis recently by including the final state soft photon radiation effect beyond the double leading logarithm approximation. The azimuthal asymmetries and acoplanarity at relatively high transverse momentum provide unique opportunities to test the resummation formalism thanks to the extremely high photon flux in UPCs. Our results clearly show the feasibility to access the sub-leading resummation effects in UPCs at the RHIC and LHC.
[ { "created": "Wed, 22 May 2024 01:11:16 GMT", "version": "v1" } ]
2024-05-24
[ [ "Zhou", "Ya-jin", "" ] ]
The coherent photons induced by relativistic heavy ions are highly linearly polarized, in close analogy to the linear polarization of gluons in a large nucleus. We proposed to measure the photon polarization through azimuthal asymmetries in dilepton production in ultra-peripheral collisions. Our prediction for the asymmetries were soon confirmed by the STAR experiment with high precision. We refined our analysis recently by including the final state soft photon radiation effect beyond the double leading logarithm approximation. The azimuthal asymmetries and acoplanarity at relatively high transverse momentum provide unique opportunities to test the resummation formalism thanks to the extremely high photon flux in UPCs. Our results clearly show the feasibility to access the sub-leading resummation effects in UPCs at the RHIC and LHC.
hep-ph/0511209
Jean-Marc Richard
J.M. Richard (LPSC)
Perspectives in hadron spectroscopy
Invited talk at the XIth International Conference on Elastic and Diffractive Scattering, Blois, France, May 15-20, 2005 - To appear in the proceedings
null
null
LPSC 05113
hep-ph
null
A brief survey is presented of selected recent results in hadron spectroscopy and related theoretical studies. This includes the pentaquarks and hadrons containing one or two charmed quarks or antiquarks.
[ { "created": "Thu, 17 Nov 2005 09:04:07 GMT", "version": "v1" }, { "created": "Mon, 21 Nov 2005 09:01:21 GMT", "version": "v2" } ]
2007-05-23
[ [ "Richard", "J. M.", "", "LPSC" ] ]
A brief survey is presented of selected recent results in hadron spectroscopy and related theoretical studies. This includes the pentaquarks and hadrons containing one or two charmed quarks or antiquarks.
hep-ph/9907546
Benjamin Earle White
B. E. White
Fracture functions in the very forward limit
4 pages, 3 figures, LaTeX 2e; talk at QCD99 Montpellier
Nucl.Phys.Proc.Suppl. 86 (2000) 126-129
10.1016/S0920-5632(00)00553-3
null
hep-ph
null
This talk gives a brief discussion of extended fracture functions, which parametrise the non-perturbative physics in the target fragmentation region of semi-inclusive DIS. In the forward limit z -> 1, it can be seen that fracture functions can be identified with insertions of composite operators. This enables polarised fracture functions to be used to test a target-independence hypothesis of the ``proton spin effect''.
[ { "created": "Thu, 29 Jul 1999 14:28:50 GMT", "version": "v1" }, { "created": "Fri, 27 Aug 1999 14:54:40 GMT", "version": "v2" } ]
2009-10-31
[ [ "White", "B. E.", "" ] ]
This talk gives a brief discussion of extended fracture functions, which parametrise the non-perturbative physics in the target fragmentation region of semi-inclusive DIS. In the forward limit z -> 1, it can be seen that fracture functions can be identified with insertions of composite operators. This enables polarised fracture functions to be used to test a target-independence hypothesis of the ``proton spin effect''.
hep-ph/0301030
Norma Mankoc Borstnik
N. Mankoc Borstnik, H. Bech Nielsen, C.D. Froggatt, D. Lukman, R. B. Nevzorov, K. A. Ter-Martirosyan, M. A. Trusov, L.V. Laperashvili, D.A. Ryzhikh, Y. Takanishi, R. Erdem
Proceedings to the workshops 'What comes beyond the Standard model', 2000, 2001, 2002, Volume 2: Proceedings (Part II)
Part II contains 8 articles by different authors inspired by the discussions at the Bled workshops (remaining 7 articles are included in Part I, which is available as hep-ph/0301029). The published Proceedings contains both parts. Editors were N. Mankoc Borstnik, H. Bech Nielsen, C.D. Froggatt, D. Lukman
Bled workshops in physics, Vol.3, No. 4, DMFA-Zaloznistvo, Ljubljana, Dec. 2002
null
null
hep-ph
null
Contents (Part 2): 8.Renormalization of Coupling Constants in the Minimal SUSY Models (R. B. Nevzorov, K. A. Ter-Martirosyan and M. A. Trusov) 9.Multiple Point Model and Phase Transition Couplings ...(L.V. Laperashvili, D.A. Ryzhikh and H.B. Nielsen) 10.Family Replicated Fit of All Quark and Lepton Masses and Mixings (H. B. Nielsen and Y. Takanishi) 11.Family Replicated Calculation of Baryogenesis (H. B. Nielsen and Y. Takanishi) 12. Neutrino Oscillations in Vacuum on the Large Distance (D.A. Ryzhikh and K.A. Ter-Martirosyan) 13. Possibility of an Additional Source of Time Reversal Violation for Neutrinos (R. Erdem) 14.Quark-Lepton Masses and the Neutrino Puzzle in the AGUT Model (C.D. Froggatt) 15.Neutrinos in the Family Replicated Gauge Group Model (C.D. Froggatt) (Contents of Part 1 [hep-ph/0301029]: 1.Derivation of Lorentz Invariance and Three Space Dimensions in Generic Field Theory (C D. Froggatt and H. B. Nielsen) 2.Unitary Representations, Noncompact Groups SO(q; d - q)...(N. Mankoc Borstnik, H. B. Nielsen and D. Lukman) 3.Weyl Spinor of SO(1; 13), Families of Spinors ...(A. Borstnik Bracic and N. Mankoc Borstnik) 4.A Tight Packing Problem (A. Kleppe) 5.Why so Few Particle Species? ... (D.L. Bennett and A. Kleppe) 6.About Number of Families (D. Lukman, A. Kleppe and N.S. Mankoc Borstnik) 7.Coupling Constant Unification in Spin-Charge Unifying Model ....(N. Mankoc Borstnik and H. B. Nielsen))
[ { "created": "Mon, 6 Jan 2003 14:42:31 GMT", "version": "v1" } ]
2007-05-23
[ [ "Borstnik", "N. Mankoc", "" ], [ "Nielsen", "H. Bech", "" ], [ "Froggatt", "C. D.", "" ], [ "Lukman", "D.", "" ], [ "Nevzorov", "R. B.", "" ], [ "Ter-Martirosyan", "K. A.", "" ], [ "Trusov", "M. A.", "" ], [ "Laperashvili", "L. V.", "" ], [ "Ryzhikh", "D. A.", "" ], [ "Takanishi", "Y.", "" ], [ "Erdem", "R.", "" ] ]
Contents (Part 2): 8.Renormalization of Coupling Constants in the Minimal SUSY Models (R. B. Nevzorov, K. A. Ter-Martirosyan and M. A. Trusov) 9.Multiple Point Model and Phase Transition Couplings ...(L.V. Laperashvili, D.A. Ryzhikh and H.B. Nielsen) 10.Family Replicated Fit of All Quark and Lepton Masses and Mixings (H. B. Nielsen and Y. Takanishi) 11.Family Replicated Calculation of Baryogenesis (H. B. Nielsen and Y. Takanishi) 12. Neutrino Oscillations in Vacuum on the Large Distance (D.A. Ryzhikh and K.A. Ter-Martirosyan) 13. Possibility of an Additional Source of Time Reversal Violation for Neutrinos (R. Erdem) 14.Quark-Lepton Masses and the Neutrino Puzzle in the AGUT Model (C.D. Froggatt) 15.Neutrinos in the Family Replicated Gauge Group Model (C.D. Froggatt) (Contents of Part 1 [hep-ph/0301029]: 1.Derivation of Lorentz Invariance and Three Space Dimensions in Generic Field Theory (C D. Froggatt and H. B. Nielsen) 2.Unitary Representations, Noncompact Groups SO(q; d - q)...(N. Mankoc Borstnik, H. B. Nielsen and D. Lukman) 3.Weyl Spinor of SO(1; 13), Families of Spinors ...(A. Borstnik Bracic and N. Mankoc Borstnik) 4.A Tight Packing Problem (A. Kleppe) 5.Why so Few Particle Species? ... (D.L. Bennett and A. Kleppe) 6.About Number of Families (D. Lukman, A. Kleppe and N.S. Mankoc Borstnik) 7.Coupling Constant Unification in Spin-Charge Unifying Model ....(N. Mankoc Borstnik and H. B. Nielsen))
2310.20194
Zilin Yuan
Zilin Yuan, Anping Huang, Wen-Hao Zhou, Guo-Liang Ma, Mei Huang
Evolution of topological charge through chiral anomaly transport
7 pages, 6 figures
null
null
null
hep-ph nucl-th
http://creativecommons.org/licenses/by/4.0/
Built upon the state-of-the-art model a multiphase transport (AMPT), we develop a new module of chiral anomaly transport (CAT), which can trace the evolution of the initial topological charge of gauge field created through sphaleron transition at finite temperature and external magnetic field in heavy ion collisions. The eventual experimental signals of chiral magnetic effect(CME) can be measured. The CAT explicitly shows the generation and evolution of the charge separation, and the signals of CME through the CAT are quantitatively in agreement with the experimental measurements in Au+Au collision at $\sqrt{s}=200 {\rm GeV}$, and the centrality dependence of the CME fraction follows that of the fireball temperature.
[ { "created": "Tue, 31 Oct 2023 05:39:38 GMT", "version": "v1" } ]
2023-11-01
[ [ "Yuan", "Zilin", "" ], [ "Huang", "Anping", "" ], [ "Zhou", "Wen-Hao", "" ], [ "Ma", "Guo-Liang", "" ], [ "Huang", "Mei", "" ] ]
Built upon the state-of-the-art model a multiphase transport (AMPT), we develop a new module of chiral anomaly transport (CAT), which can trace the evolution of the initial topological charge of gauge field created through sphaleron transition at finite temperature and external magnetic field in heavy ion collisions. The eventual experimental signals of chiral magnetic effect(CME) can be measured. The CAT explicitly shows the generation and evolution of the charge separation, and the signals of CME through the CAT are quantitatively in agreement with the experimental measurements in Au+Au collision at $\sqrt{s}=200 {\rm GeV}$, and the centrality dependence of the CME fraction follows that of the fireball temperature.
0909.5213
Martin Schmaltz
Christian W. Bauer, Zoltan Ligeti, Martin Schmaltz, Jesse Thaler, Devin G. E. Walker
Supermodels for early LHC
11 pages, 6 figures; v2, references added
Phys.Lett.B690:280-288,2010
10.1016/j.physletb.2010.05.032
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate what new physics signatures the LHC can discover in the 2009-2010 run, beyond the expected sensitivity of the Tevatron data by 2010. We construct "supermodels", for which the LHC sensitivity even with only 10 inverse picobarn is greater than that of the Tevatron with 10 inverse femtobarn. The simplest supermodels involve s-channel resonances in the quark-antiquark and especially in the quark-quark channels. We concentrate on easily visible final states with small standard model backgrounds, and find that there are simple searches, besides those for Z' states, which could discover new physics in early LHC data. Many of these are well-suited to test searches for "more conventional" models, often discussed for multi-inverse femtobarn data sets.
[ { "created": "Tue, 29 Sep 2009 16:55:42 GMT", "version": "v1" }, { "created": "Sun, 18 Oct 2009 16:51:17 GMT", "version": "v2" } ]
2014-11-20
[ [ "Bauer", "Christian W.", "" ], [ "Ligeti", "Zoltan", "" ], [ "Schmaltz", "Martin", "" ], [ "Thaler", "Jesse", "" ], [ "Walker", "Devin G. E.", "" ] ]
We investigate what new physics signatures the LHC can discover in the 2009-2010 run, beyond the expected sensitivity of the Tevatron data by 2010. We construct "supermodels", for which the LHC sensitivity even with only 10 inverse picobarn is greater than that of the Tevatron with 10 inverse femtobarn. The simplest supermodels involve s-channel resonances in the quark-antiquark and especially in the quark-quark channels. We concentrate on easily visible final states with small standard model backgrounds, and find that there are simple searches, besides those for Z' states, which could discover new physics in early LHC data. Many of these are well-suited to test searches for "more conventional" models, often discussed for multi-inverse femtobarn data sets.
2112.03963
Vin\'icius Oliveira
Vin\'icius Oliveira and C. A. de S. Pires
Pandax-4T limits on $Z^\prime$ mass in 3-3-1LHN model
15 pages, 8 figures, Matches version accepted in Phys. Rev. D
null
10.1103/PhysRevD.106.015031
null
hep-ph astro-ph.HE
http://creativecommons.org/licenses/by/4.0/
The framework of the so-called 3-3-1LHN model may accommodate two different, but viable, scenarios of dark matter: one involving a heavy Dirac neutrino , $N_1$, or another having a scalar, $\phi$, as dark matter candidate. In both cases the dark matter phenomenology, relic abundance and scattering cross section off of nuclei, is controlled by exchange of $Z^{\prime}$. We then investigate the impact on the parameter space $(M_{Z^{\prime}}\,,\,M_{(N_1\,,\, \phi)})$ due to the recent Pandax-4T experimental result in both scenarios. First, the Pandax-4T experiment excludes scenarios with dark matter mass below $1.9$ TeV. Concerning $Z^{\prime}$, we find the lower bound $M_{Z^{\prime}}> 4.1$ TeV for the case when $N_1$ as the dark matter and $ M_{Z^{\prime}}>5.7$ TeV for the other case. This implies that the 3-3-1 symmetry is spontaneously broken above $10$ TeV scale. We also comment on the contributions to the relic abundance of processes involving flavor changing neutral current mediated by $Z^{\prime}$.
[ { "created": "Tue, 7 Dec 2021 19:44:33 GMT", "version": "v1" }, { "created": "Sun, 31 Jul 2022 12:39:19 GMT", "version": "v2" } ]
2022-08-02
[ [ "Oliveira", "Vinícius", "" ], [ "Pires", "C. A. de S.", "" ] ]
The framework of the so-called 3-3-1LHN model may accommodate two different, but viable, scenarios of dark matter: one involving a heavy Dirac neutrino , $N_1$, or another having a scalar, $\phi$, as dark matter candidate. In both cases the dark matter phenomenology, relic abundance and scattering cross section off of nuclei, is controlled by exchange of $Z^{\prime}$. We then investigate the impact on the parameter space $(M_{Z^{\prime}}\,,\,M_{(N_1\,,\, \phi)})$ due to the recent Pandax-4T experimental result in both scenarios. First, the Pandax-4T experiment excludes scenarios with dark matter mass below $1.9$ TeV. Concerning $Z^{\prime}$, we find the lower bound $M_{Z^{\prime}}> 4.1$ TeV for the case when $N_1$ as the dark matter and $ M_{Z^{\prime}}>5.7$ TeV for the other case. This implies that the 3-3-1 symmetry is spontaneously broken above $10$ TeV scale. We also comment on the contributions to the relic abundance of processes involving flavor changing neutral current mediated by $Z^{\prime}$.
2109.06124
Albi Kerbizi
A. Kerbizi, X. Artru, A. Martin
Production of vector mesons in the String+${}^3P_0$ model of polarized quark fragmentation
21 pages, 23 figures, 2 appendices
null
10.1103/PhysRevD.104.114038
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The production of vector mesons in the fragmentation process of polarized quarks is studied within the recursive String+${}^3P_0$ model, improving a previous version of the model in which the production of pseudoscalar mesons only was considered. Two types of couplings of the vector meson to quarks are introduced, their coupling constants being the additional free parameters of the model. The angular distribution of the decay products of the polarized vector meson is deduced from the spin density matrix of the meson and the spin information is propagated along the fragmentation chain taking into account the entanglement of spin states. The new model is implemented in a stand alone Monte Carlo program utilized to investigate in detail kinematic distributions and transverse spin asymmetries. The sensitivity of these observables to the new free parameters is discussed and the Monte Carlo results are compared with experimental data on transverse spin asymmetries.
[ { "created": "Mon, 13 Sep 2021 16:59:07 GMT", "version": "v1" } ]
2022-01-12
[ [ "Kerbizi", "A.", "" ], [ "Artru", "X.", "" ], [ "Martin", "A.", "" ] ]
The production of vector mesons in the fragmentation process of polarized quarks is studied within the recursive String+${}^3P_0$ model, improving a previous version of the model in which the production of pseudoscalar mesons only was considered. Two types of couplings of the vector meson to quarks are introduced, their coupling constants being the additional free parameters of the model. The angular distribution of the decay products of the polarized vector meson is deduced from the spin density matrix of the meson and the spin information is propagated along the fragmentation chain taking into account the entanglement of spin states. The new model is implemented in a stand alone Monte Carlo program utilized to investigate in detail kinematic distributions and transverse spin asymmetries. The sensitivity of these observables to the new free parameters is discussed and the Monte Carlo results are compared with experimental data on transverse spin asymmetries.
hep-ph/9304285
null
Debajyoti Choudhury, Probir Roy and Rahul Sinha
Oblique electroweak corrections and triple vector boson couplings
LaTeX manuscript (11 pages, 3 figures -- uuencoded postscript file included) TIFR--TH/93--08. Revised. An error in the previous version has been corrected. Some expressions and the figures have changed slightly, but the qualitative conclusions are the same
null
null
null
hep-ph
null
We relate all $C$-- and $P$--invariant anomalous triple vector--boson couplings to the oblique electroweak parameters. LEP constraints on the latter then yield the strongest and most general simultaneous bounds to date on the former. Even if the oblique parameters assume their Standard Model values precisely, these bounds would not shrink to zero---thus underscoring the need for direct experimental probes at future colliders.
[ { "created": "Wed, 21 Apr 1993 21:55:10 GMT", "version": "v1" }, { "created": "Tue, 18 May 1993 12:58:59 GMT", "version": "v2" } ]
2008-02-03
[ [ "Choudhury", "Debajyoti", "" ], [ "Roy", "Probir", "" ], [ "Sinha", "Rahul", "" ] ]
We relate all $C$-- and $P$--invariant anomalous triple vector--boson couplings to the oblique electroweak parameters. LEP constraints on the latter then yield the strongest and most general simultaneous bounds to date on the former. Even if the oblique parameters assume their Standard Model values precisely, these bounds would not shrink to zero---thus underscoring the need for direct experimental probes at future colliders.