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2104.07047
Antonio Enrique C\'arcamo Hern\'andez
A. E. C\'arcamo Hern\'andez, Sergey Kovalenko, M. Maniatis, Ivan Schmidt
Fermion mass hierarchy and g-2 anomalies in an extended 3HDM Model
Matches published version in JHEP
JHEP 10 (2021) 036
10.1007/JHEP10(2021)036
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose an extension of the three-Higgs-doublet model (3HDM), where the Standard Model (SM) particle content is enlarged by the inclusion of two inert $SU_{2L}$ scalar doublets, three inert and two active electrically neutral gauge singlet scalars, charged vector like fermions and Majorana neutrinos. These additional particles are introduced to generate the SM fermion mass hierarchy from a sequential loop suppression mechanism. In our model the top and exotic fermion masses appear at tree level, whereas the remaining fermions get their masses radiatively. Specifically, bottom, charm, tau and muon masses appear at 1-loop; the masses for the light up, down and strange quarks as well as for the electron at 2-loop and masses for the light active neutrinos at 3-loop. Our model successfully accounts for SM fermion masses and mixings and accommodates the observed Dark Matter relic density, the electron and muon anomalous magnetic moments, as well the constraints arising from charged Lepton Flavor Violating (LFV) processes. The proposed model predicts charged LFV decays within the reach of forthcoming experiments.
[ { "created": "Wed, 14 Apr 2021 18:01:07 GMT", "version": "v1" }, { "created": "Mon, 11 Oct 2021 18:01:57 GMT", "version": "v2" } ]
2021-10-13
[ [ "Hernández", "A. E. Cárcamo", "" ], [ "Kovalenko", "Sergey", "" ], [ "Maniatis", "M.", "" ], [ "Schmidt", "Ivan", "" ] ]
We propose an extension of the three-Higgs-doublet model (3HDM), where the Standard Model (SM) particle content is enlarged by the inclusion of two inert $SU_{2L}$ scalar doublets, three inert and two active electrically neutral gauge singlet scalars, charged vector like fermions and Majorana neutrinos. These additional particles are introduced to generate the SM fermion mass hierarchy from a sequential loop suppression mechanism. In our model the top and exotic fermion masses appear at tree level, whereas the remaining fermions get their masses radiatively. Specifically, bottom, charm, tau and muon masses appear at 1-loop; the masses for the light up, down and strange quarks as well as for the electron at 2-loop and masses for the light active neutrinos at 3-loop. Our model successfully accounts for SM fermion masses and mixings and accommodates the observed Dark Matter relic density, the electron and muon anomalous magnetic moments, as well the constraints arising from charged Lepton Flavor Violating (LFV) processes. The proposed model predicts charged LFV decays within the reach of forthcoming experiments.
hep-ph/0508215
Fredrick Olness
Stefan Berge, Pavel M. Nadolsky, Fredrick I. Olness, C.-P. Yuan
q_T Uncertainties for W and Z Production
4 pages, 2 figures; contribution to the XIII International Workshop on Deep Inelastic Scattering (DIS 2005)
null
10.1063/1.2122139
ANL-HEP-PR-05-67
hep-ph
null
Analysis of semi-inclusive DIS hadroproduction suggests broadening of transverse momentum distributions at small x below 1E-3 ~ 1E-2 which can be modeled in the Collins-Soper-Sterman formalism by a modification of impact parameter dependent parton densities. We investigate these consequences for the production of electroweak bosons at the Tevatron and the LHC. If substantial small-x broadening is observed in forward Z boson production in the Tevatron Run-2, it will strongly affect the predicted q_T distributions for W and Z boson production at the LHC.
[ { "created": "Mon, 22 Aug 2005 15:45:11 GMT", "version": "v1" } ]
2015-06-25
[ [ "Berge", "Stefan", "" ], [ "Nadolsky", "Pavel M.", "" ], [ "Olness", "Fredrick I.", "" ], [ "Yuan", "C. -P.", "" ] ]
Analysis of semi-inclusive DIS hadroproduction suggests broadening of transverse momentum distributions at small x below 1E-3 ~ 1E-2 which can be modeled in the Collins-Soper-Sterman formalism by a modification of impact parameter dependent parton densities. We investigate these consequences for the production of electroweak bosons at the Tevatron and the LHC. If substantial small-x broadening is observed in forward Z boson production in the Tevatron Run-2, it will strongly affect the predicted q_T distributions for W and Z boson production at the LHC.
2303.12427
Wen Chen
Wen Chen
A Representation Transformation of Parametric Feynman Integrals
5 pages
null
null
null
hep-ph hep-th
http://creativecommons.org/licenses/by/4.0/
A transformation is applied to the parametric representation of Feynman integrals. The obtained representation and the original parametric representation are dual to each other. For integrals with momentum-space correspondences, the ``new'' representation is just the Baikov's representation.
[ { "created": "Wed, 22 Mar 2023 09:57:32 GMT", "version": "v1" } ]
2023-03-23
[ [ "Chen", "Wen", "" ] ]
A transformation is applied to the parametric representation of Feynman integrals. The obtained representation and the original parametric representation are dual to each other. For integrals with momentum-space correspondences, the ``new'' representation is just the Baikov's representation.
0709.3309
Yazid Delenda
Mrinal Dasgupta and Yazid Delenda
Aspects of power corrections in hadron-hadron collisions
15 pages, 1 figure, uses JHEP3.cls
JHEP0711:013,2007
10.1088/1126-6708/2007/11/013
MAN/HEP/2007/14
hep-ph
null
The program of understanding inverse-power law corrections to event shapes and energy flow observables in e+ e- annihilation to two jets and DIS (1+1) jets has been a significant success of QCD phenomenology over the last decade. The important extension of this program to similar observables in hadron collisions is not straightforward, being obscured by both conceptual and technical issues. In this paper we shed light on some of these issues by providing an estimate of power corrections to the inter-jet E_t flow distribution in hadron collisions using the techniques that were employed in the e+ e- annihilation and DIS cases.
[ { "created": "Thu, 20 Sep 2007 21:47:34 GMT", "version": "v1" } ]
2008-11-26
[ [ "Dasgupta", "Mrinal", "" ], [ "Delenda", "Yazid", "" ] ]
The program of understanding inverse-power law corrections to event shapes and energy flow observables in e+ e- annihilation to two jets and DIS (1+1) jets has been a significant success of QCD phenomenology over the last decade. The important extension of this program to similar observables in hadron collisions is not straightforward, being obscured by both conceptual and technical issues. In this paper we shed light on some of these issues by providing an estimate of power corrections to the inter-jet E_t flow distribution in hadron collisions using the techniques that were employed in the e+ e- annihilation and DIS cases.
hep-ph/0611287
Erik Barto\v{s} PhD.
E. Bartos, E. A. Kuraev, Yu. P. Peresunko, E. A. Vinokurov
Recoil proton distribution in high energy photoproduction processes
LaTeX2e, 4 pages, 3 figures
Eur.Phys.J.C52:173-176,2007
10.1140/epjc/s10052-007-0363-y
null
hep-ph
null
For high energy linearly polarized photon--proton scattering we have calculated the azimuthal and polar angle distributions in inclusive on recoil proton experimental setup. We have taken into account the production of lepton and pseudoscalar meson charged pairs. The typical values of cross sections are of order of hundreds of picobarn. The size of polarization effects are of order of several percents. The results are generalized for the case of electroproduction processes on the proton at rest and for high energy proton production process on resting proton.
[ { "created": "Wed, 22 Nov 2006 11:45:37 GMT", "version": "v1" } ]
2008-11-26
[ [ "Bartos", "E.", "" ], [ "Kuraev", "E. A.", "" ], [ "Peresunko", "Yu. P.", "" ], [ "Vinokurov", "E. A.", "" ] ]
For high energy linearly polarized photon--proton scattering we have calculated the azimuthal and polar angle distributions in inclusive on recoil proton experimental setup. We have taken into account the production of lepton and pseudoscalar meson charged pairs. The typical values of cross sections are of order of hundreds of picobarn. The size of polarization effects are of order of several percents. The results are generalized for the case of electroproduction processes on the proton at rest and for high energy proton production process on resting proton.
2011.09618
Lingyun Dai
Wen Qin, Ling-Yun Dai and Jorge Portoles
Two and Three Pseudoscalar Production in $e^{+}e^{-}$ annihilation and their contributions to $(g-2)_{\mu}$
41 pages, 2 figures, 4 tables, to be the same as the published version
null
10.1007/JHEP03(2021)092
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A coherent study of $e^{+}e^{-}$ annihilation into two ($\pi^{+}\pi^{-}$,$K^{+}K^{-}$) and three ($\pi^{+}\pi^{-}\pi^{0},\pi^{+}\pi^{-}\eta$) pseudoscalar meson production is carried out within the framework of resonance chiral theory in energy region $E\lesssim 2 \, \mathrm{GeV}$. The work of {[}L. Y. Dai, J. Portol\'es, and O. Shekhovtsova, Phys. Rev. D 88,056001 (2013){]} is revisited with the latest experimental data and a joint analysis of two pseudoscalar meson production. Hence, we evaluate the lowest order hadronic vacuum polarization contributions of those two and three pseudoscalar processes to the anomalous magnetic moment of the muon. We also estimate some higher-order additions led by the same hadronic vacuum polarization. Combined with the other contributions from the standard model, the theoretical prediction differs still by $(21.6 \pm 7.4)\times 10^{-10}$ (2.9$\sigma$) from the experimental value.
[ { "created": "Thu, 19 Nov 2020 02:35:28 GMT", "version": "v1" }, { "created": "Wed, 3 Mar 2021 19:03:17 GMT", "version": "v2" } ]
2021-03-31
[ [ "Qin", "Wen", "" ], [ "Dai", "Ling-Yun", "" ], [ "Portoles", "Jorge", "" ] ]
A coherent study of $e^{+}e^{-}$ annihilation into two ($\pi^{+}\pi^{-}$,$K^{+}K^{-}$) and three ($\pi^{+}\pi^{-}\pi^{0},\pi^{+}\pi^{-}\eta$) pseudoscalar meson production is carried out within the framework of resonance chiral theory in energy region $E\lesssim 2 \, \mathrm{GeV}$. The work of {[}L. Y. Dai, J. Portol\'es, and O. Shekhovtsova, Phys. Rev. D 88,056001 (2013){]} is revisited with the latest experimental data and a joint analysis of two pseudoscalar meson production. Hence, we evaluate the lowest order hadronic vacuum polarization contributions of those two and three pseudoscalar processes to the anomalous magnetic moment of the muon. We also estimate some higher-order additions led by the same hadronic vacuum polarization. Combined with the other contributions from the standard model, the theoretical prediction differs still by $(21.6 \pm 7.4)\times 10^{-10}$ (2.9$\sigma$) from the experimental value.
1009.3934
David Sanford
Jonathan L. Feng and David Sanford
Heart of Darkness: The Significance of the Zeptobarn Scale for Neutralino Direct Detection
35 pages, 11 figures; v2: references added, figures extended to 2 TeV neutralino masses, XENON100 results included, published version
JCAP 1105:018,2011
10.1088/1475-7516/2011/05/018
UCI-TR-2010-16
hep-ph astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The direct detection of dark matter through its elastic scattering off nucleons is among the most promising methods for establishing the particle identity of dark matter. The current bound on the spin-independent scattering cross section is sigma^SI < 10 zb for dark matter masses m_chi ~ 100 GeV, with improved sensitivities expected soon. We examine the implications of this progress for neutralino dark matter. We work in a supersymmetric framework well-suited to dark matter studies that is simple and transparent, with models defined in terms of four weak-scale parameters. We first show that robust constraints on electric dipole moments motivate large sfermion masses mtilde > 1 TeV, effectively decoupling squarks and sleptons from neutralino dark matter phenomenology. In this case, we find characteristic cross sections in the narrow range 1 zb < sigma^SI < 40 zb for m_chi > 70 GeV. As sfermion masses are lowered to near their experimental limit mtilde ~ 400 GeV, the upper and lower limits of this range are extended, but only by factors of around two, and the lower limit is not significantly altered by relaxing many particle physics assumptions, varying the strange quark content of the nucleon, including the effects of galactic small-scale structure, or assuming other components of dark matter. Experiments are therefore rapidly entering the heart of dark matter-favored supersymmetry parameter space. If no signal is seen, supersymmetric models must contain some level of fine-tuning, and we identify and analyze several possibilities. Barring large cancellations, however, in a large and generic class of models, if thermal relic neutralinos are a significant component of dark matter, experiments will discover them as they probe down to the zeptobarn scale.
[ { "created": "Mon, 20 Sep 2010 20:00:08 GMT", "version": "v1" }, { "created": "Thu, 12 May 2011 15:39:57 GMT", "version": "v2" } ]
2011-05-25
[ [ "Feng", "Jonathan L.", "" ], [ "Sanford", "David", "" ] ]
The direct detection of dark matter through its elastic scattering off nucleons is among the most promising methods for establishing the particle identity of dark matter. The current bound on the spin-independent scattering cross section is sigma^SI < 10 zb for dark matter masses m_chi ~ 100 GeV, with improved sensitivities expected soon. We examine the implications of this progress for neutralino dark matter. We work in a supersymmetric framework well-suited to dark matter studies that is simple and transparent, with models defined in terms of four weak-scale parameters. We first show that robust constraints on electric dipole moments motivate large sfermion masses mtilde > 1 TeV, effectively decoupling squarks and sleptons from neutralino dark matter phenomenology. In this case, we find characteristic cross sections in the narrow range 1 zb < sigma^SI < 40 zb for m_chi > 70 GeV. As sfermion masses are lowered to near their experimental limit mtilde ~ 400 GeV, the upper and lower limits of this range are extended, but only by factors of around two, and the lower limit is not significantly altered by relaxing many particle physics assumptions, varying the strange quark content of the nucleon, including the effects of galactic small-scale structure, or assuming other components of dark matter. Experiments are therefore rapidly entering the heart of dark matter-favored supersymmetry parameter space. If no signal is seen, supersymmetric models must contain some level of fine-tuning, and we identify and analyze several possibilities. Barring large cancellations, however, in a large and generic class of models, if thermal relic neutralinos are a significant component of dark matter, experiments will discover them as they probe down to the zeptobarn scale.
1711.11260
David Blaschke
Thomas Klaehn, David Blaschke
Strange matter in compact stars
8 pages, 1 figure, accepted for publication in Proceedings of "Strangeness in Quark Matter 2017", Utrecht (EPJ WoC)
null
10.1051/epjconf/201817108001
null
hep-ph astro-ph.HE nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We discuss possible scenarios for the existence of strange matter in compact stars. The appearance of hyperons leads to a hyperon puzzle in ab-initio approaches based on effective baryon-baryon potentials but is not a severe problem in relativistic mean field models. In general, the puzzle can be resolved in a natural way if hadronic matter gets stiffened at supersaturation densities, an effect based on the quark Pauli quenching between hadrons. We explain the conflict between the necessity to implement dynamical chiral symmetry breaking into a model description and the conditions for the appearance of absolutely stable strange quark matter that require both, approximately masslessness of quarks and a mechanism of confinement. The role of strangeness in compact stars (hadronic or quark matter realizations) remains unsettled. It is not excluded that strangeness plays no role in compact stars at all. To answer the question whether the case of absolutely stable strange quark matter can be excluded on theoretical grounds requires an understanding of dense matter that we have not yet reached.
[ { "created": "Thu, 30 Nov 2017 07:48:11 GMT", "version": "v1" } ]
2018-03-14
[ [ "Klaehn", "Thomas", "" ], [ "Blaschke", "David", "" ] ]
We discuss possible scenarios for the existence of strange matter in compact stars. The appearance of hyperons leads to a hyperon puzzle in ab-initio approaches based on effective baryon-baryon potentials but is not a severe problem in relativistic mean field models. In general, the puzzle can be resolved in a natural way if hadronic matter gets stiffened at supersaturation densities, an effect based on the quark Pauli quenching between hadrons. We explain the conflict between the necessity to implement dynamical chiral symmetry breaking into a model description and the conditions for the appearance of absolutely stable strange quark matter that require both, approximately masslessness of quarks and a mechanism of confinement. The role of strangeness in compact stars (hadronic or quark matter realizations) remains unsettled. It is not excluded that strangeness plays no role in compact stars at all. To answer the question whether the case of absolutely stable strange quark matter can be excluded on theoretical grounds requires an understanding of dense matter that we have not yet reached.
2006.04820
Philip S{\o}rensen
Sergey Sibiryakov, Philip S{\o}rensen, Tien-Tien Yu
BBN constraints on universally-coupled ultralight scalar dark matter
23 pages + appendices and bibliography, 6 figures, v2: typos corrected, expanded discussion around eq. 4.5, published version
J. High Energ. Phys. 2020, 75 (2020)
10.1007/JHEP12(2020)075
DESY-19-234, CERN-TH-2020-091, INR-TH-2020-001
hep-ph astro-ph.CO
http://creativecommons.org/licenses/by/4.0/
Ultralight scalar dark matter can interact with all massive Standard Model particles through a universal coupling. Such a coupling modifies the Standard Model particle masses and affects the dynamics of Big Bang Nucleosynthesis. We model the cosmological evolution of the dark matter, taking into account the modifications of the scalar mass by the environment as well as the full dynamics of Big Bang Nucleosynthesis. We find that precision measurements of the helium-4 abundance set stringent constraints on the available parameter space, and that these constraints are strongly affected by both the dark matter environmental mass and the dynamics of the neutron freeze-out. Furthermore, we perform the analysis in both the Einstein and Jordan frames, the latter of which allows us to implement the model into numerical Big Bang Nucleosynthesis codes and analyze additional light elements. The numerical analysis shows that the constraint from helium-4 dominates over deuterium, and that the effect on lithium is insufficient to solve the lithium problem. Comparing to several other probes, we find that Big Bang Nucleosynthesis sets the strongest constraints for the majority of the parameter space.
[ { "created": "Mon, 8 Jun 2020 18:00:02 GMT", "version": "v1" }, { "created": "Mon, 14 Dec 2020 19:55:53 GMT", "version": "v2" } ]
2020-12-16
[ [ "Sibiryakov", "Sergey", "" ], [ "Sørensen", "Philip", "" ], [ "Yu", "Tien-Tien", "" ] ]
Ultralight scalar dark matter can interact with all massive Standard Model particles through a universal coupling. Such a coupling modifies the Standard Model particle masses and affects the dynamics of Big Bang Nucleosynthesis. We model the cosmological evolution of the dark matter, taking into account the modifications of the scalar mass by the environment as well as the full dynamics of Big Bang Nucleosynthesis. We find that precision measurements of the helium-4 abundance set stringent constraints on the available parameter space, and that these constraints are strongly affected by both the dark matter environmental mass and the dynamics of the neutron freeze-out. Furthermore, we perform the analysis in both the Einstein and Jordan frames, the latter of which allows us to implement the model into numerical Big Bang Nucleosynthesis codes and analyze additional light elements. The numerical analysis shows that the constraint from helium-4 dominates over deuterium, and that the effect on lithium is insufficient to solve the lithium problem. Comparing to several other probes, we find that Big Bang Nucleosynthesis sets the strongest constraints for the majority of the parameter space.
1911.08486
Markus Ebert
Markus A. Ebert and Frank J. Tackmann
Impact of Isolation and Fiducial Cuts on $q_T$ and N-Jettiness Subtractions
27 pages, 4 figures; v2: minor changes, journal version
JHEP 03 (2020) 158
10.1007/JHEP03(2020)158
DESY 19-199, MIT-CTP/5158
hep-ph
http://creativecommons.org/licenses/by/4.0/
Kinematic selection cuts and isolation requirements are a necessity in experimental measurements for identifying prompt leptons and photons that originate from the hard-interaction process of interest. We analyze how such cuts affect the application of the $q_T$ and $N$-jettiness subtraction methods for fixed-order calculations. We consider both fixed-cone and smooth-cone isolation methods. We find that kinematic selection and isolation cuts both induce parametrically enhanced power corrections with considerably slower convergence compared to the standard power corrections that are already present in inclusive cross sections without additional cuts. Using analytic arguments at next-to-leading order we derive their general scaling behavior as a function of the subtraction cutoff. We also study their numerical impact for the case of gluon-fusion Higgs production in the $H\to\gamma\gamma$ decay mode and for $pp\to\gamma\gamma$ direct diphoton production. We find that the relative enhancement of the additional cut-induced power corrections tends to be more severe for $q_T$, where it can reach an order of magnitude or more, depending on the choice of parameters and subtraction cutoffs. We discuss how all such cuts can be incorporated without causing additional power corrections by implementing the subtractions differentially rather than through a global slicing method. We also highlight the close relation of this formulation of the subtractions to the projection-to-Born method.
[ { "created": "Tue, 19 Nov 2019 19:00:00 GMT", "version": "v1" }, { "created": "Wed, 1 Apr 2020 16:27:33 GMT", "version": "v2" } ]
2020-04-02
[ [ "Ebert", "Markus A.", "" ], [ "Tackmann", "Frank J.", "" ] ]
Kinematic selection cuts and isolation requirements are a necessity in experimental measurements for identifying prompt leptons and photons that originate from the hard-interaction process of interest. We analyze how such cuts affect the application of the $q_T$ and $N$-jettiness subtraction methods for fixed-order calculations. We consider both fixed-cone and smooth-cone isolation methods. We find that kinematic selection and isolation cuts both induce parametrically enhanced power corrections with considerably slower convergence compared to the standard power corrections that are already present in inclusive cross sections without additional cuts. Using analytic arguments at next-to-leading order we derive their general scaling behavior as a function of the subtraction cutoff. We also study their numerical impact for the case of gluon-fusion Higgs production in the $H\to\gamma\gamma$ decay mode and for $pp\to\gamma\gamma$ direct diphoton production. We find that the relative enhancement of the additional cut-induced power corrections tends to be more severe for $q_T$, where it can reach an order of magnitude or more, depending on the choice of parameters and subtraction cutoffs. We discuss how all such cuts can be incorporated without causing additional power corrections by implementing the subtractions differentially rather than through a global slicing method. We also highlight the close relation of this formulation of the subtractions to the projection-to-Born method.
hep-ph/9410365
null
E. Farhi, J. Goldstone, S. Gutmann, K. Rajagopal, R. Singleton
Fermion Production in the Background of Minkowski Space Classical Solutions in Spontaneously Broken Gauge Theory
Version to be published. Argument showing that the topological charge of solutions is undefined has been strengthened and clarified. Conclusions unchanged
Phys.Rev. D51 (1995) 4561-4572
10.1103/PhysRevD.51.4561
CTP-2370, HUTP-94/A038, BU-HEP-94-30
hep-ph hep-th
null
We investigate fermion production in the background of Minkowski space solutions to the equations of motion of $SU(2)$ gauge theory spontaneously broken via the Higgs mechanism. First, we attempt to evaluate the topological charge $Q$ of the solutions. We find that for solutions $Q$ is not well-defined as an integral over all space-time. Solutions can profitably be characterized by the (integer-valued) change in Higgs winding number $\Delta N_H$. We show that solutions which dissipate at early and late times and which have nonzero $\Delta N_H$ must have at least the sphaleron energy. We show that if we couple a quantized massive chiral fermion to a classical background given by a solution, the number of fermions produced is $\Delta N_H$, and is not related to $Q$.
[ { "created": "Tue, 25 Oct 1994 15:40:05 GMT", "version": "v1" }, { "created": "Fri, 3 Feb 1995 22:24:52 GMT", "version": "v2" } ]
2009-10-28
[ [ "Farhi", "E.", "" ], [ "Goldstone", "J.", "" ], [ "Gutmann", "S.", "" ], [ "Rajagopal", "K.", "" ], [ "Singleton", "R.", "" ] ]
We investigate fermion production in the background of Minkowski space solutions to the equations of motion of $SU(2)$ gauge theory spontaneously broken via the Higgs mechanism. First, we attempt to evaluate the topological charge $Q$ of the solutions. We find that for solutions $Q$ is not well-defined as an integral over all space-time. Solutions can profitably be characterized by the (integer-valued) change in Higgs winding number $\Delta N_H$. We show that solutions which dissipate at early and late times and which have nonzero $\Delta N_H$ must have at least the sphaleron energy. We show that if we couple a quantized massive chiral fermion to a classical background given by a solution, the number of fermions produced is $\Delta N_H$, and is not related to $Q$.
1010.1835
Fatemeh Taghavi Shahri
Fatemeh Taghavi Shahri, Firooz Arash
Non-Singlet spin structure function in the valon model and low x scaling behavior of $g_{1}^{NS}$ and $g_1^p$
16 pages, 10 figures
Phys.Rev.C82:035205,2010
10.1103/PhysRevC.82.035205
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A next-to-leading order QCD calculation of non-singlet spin structure function, $g_{1}^{NS} $ is presented within the valon representation of Hadrons. In the valon model, it is assumed that a nucleon is composed of three dressed valence quarks: the valons which have their own internal structure, the valence quark with its associated sea quarks and gluons. The results are in good agreement with all available data from SMC, E143, HERMES and with the newly released data from COMPASS experiments. It appears that the small x tail of $g_{1}^{NS}$ can be described by a single Regge-type exchange. The relevant parameter of this exchange is given. Finally we show that the polarized proton structure function has a scaling behavior at small x. The relevant parameters of this behavior are given too.
[ { "created": "Sat, 9 Oct 2010 11:26:01 GMT", "version": "v1" } ]
2014-11-21
[ [ "Shahri", "Fatemeh Taghavi", "" ], [ "Arash", "Firooz", "" ] ]
A next-to-leading order QCD calculation of non-singlet spin structure function, $g_{1}^{NS} $ is presented within the valon representation of Hadrons. In the valon model, it is assumed that a nucleon is composed of three dressed valence quarks: the valons which have their own internal structure, the valence quark with its associated sea quarks and gluons. The results are in good agreement with all available data from SMC, E143, HERMES and with the newly released data from COMPASS experiments. It appears that the small x tail of $g_{1}^{NS}$ can be described by a single Regge-type exchange. The relevant parameter of this exchange is given. Finally we show that the polarized proton structure function has a scaling behavior at small x. The relevant parameters of this behavior are given too.
hep-ph/0210420
Michael Klasen
Stefan Berge, Michael Klasen (Univ. Hamburg)
The Production of Gluino Pairs in High Energy e+ e- Collisions
Talk presented at the SUSY 2002 conference. 7+1 pages, 5 figures
null
null
null
hep-ph
null
In the Minimal Supersymmetric Standard Model (MSSM), the process e+ e- -> gluino gluino is mediated by quark/squark loops, dominantly of the third generation, where the mixing of left- and right-handed states can become large. Taking into account realistic beam polarization effects, photon and Z0-boson exchange, and current mass exclusion limits, we scan the MSSM parameter space for various e+e- center-of-mass energies to determine the regions, where gluino production should be visible.
[ { "created": "Wed, 30 Oct 2002 15:16:35 GMT", "version": "v1" } ]
2007-05-23
[ [ "Berge", "Stefan", "", "Univ. Hamburg" ], [ "Klasen", "Michael", "", "Univ. Hamburg" ] ]
In the Minimal Supersymmetric Standard Model (MSSM), the process e+ e- -> gluino gluino is mediated by quark/squark loops, dominantly of the third generation, where the mixing of left- and right-handed states can become large. Taking into account realistic beam polarization effects, photon and Z0-boson exchange, and current mass exclusion limits, we scan the MSSM parameter space for various e+e- center-of-mass energies to determine the regions, where gluino production should be visible.
hep-ph/9306250
Seongyoul Choi
S. Y. Choi, J. S. Shim, and H. S. Song
Factorization of gravitational Compton scattering amplitude in the linearized version of general relativity
11 pages, 1 figure(not included), Revtex 3.0, SNUTP 93-24
Phys.Rev.D48:2953-2956,1993
10.1103/PhysRevD.48.2953
null
hep-ph
null
Gravitational Compton scattering process with a massive fermion is studied in the context of the linearized gravity. Gravitational gauge invariance and graviton transversality cause the transition amplitude to be factorized into that of scalar QED Compton scattering and that of fermion QED Compton scattering with an overall kinematical factor. The factorization is shown explicitly and its physical implications are discussed.
[ { "created": "Wed, 9 Jun 1993 07:30:40 GMT", "version": "v1" } ]
2010-11-01
[ [ "Choi", "S. Y.", "" ], [ "Shim", "J. S.", "" ], [ "Song", "H. S.", "" ] ]
Gravitational Compton scattering process with a massive fermion is studied in the context of the linearized gravity. Gravitational gauge invariance and graviton transversality cause the transition amplitude to be factorized into that of scalar QED Compton scattering and that of fermion QED Compton scattering with an overall kinematical factor. The factorization is shown explicitly and its physical implications are discussed.
1707.04068
Vladimir Saleev
Anton Karpishkov, Maxim Nefedov, and Vladimir Saleev
$B{\bar B}$ angular correlations at the LHC in parton Reggeization approach merged with higher-order matrix elements
28 pages, 12 figures
Phys. Rev. D 96, 096019 (2017)
10.1103/PhysRevD.96.096019
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We calculate the angular distribution spectra between beauty ($B$) and anti-beauty ($\bar B$) mesons in proton-proton collisions in the leading order approximation of the parton Reggeization approach consistently merged with the next-to-leading order corrections from the emission of additional hard gluon. To describe b-quark hadronization we use the universal scale-depended parton-to-meson fragmentation functions extracted from the world $e^+e^-$ annihilation data. We have obtained good agreement between our predictions and data from the CMS Collaboration at the energy $\sqrt{S}=7$ TeV for $B \bar B$ angular correlations within uncertainties and without free parameters. Predictions for analogous correlation observables at $\sqrt{S}=13$ TeV are provided.
[ { "created": "Thu, 13 Jul 2017 11:19:33 GMT", "version": "v1" } ]
2017-11-29
[ [ "Karpishkov", "Anton", "" ], [ "Nefedov", "Maxim", "" ], [ "Saleev", "Vladimir", "" ] ]
We calculate the angular distribution spectra between beauty ($B$) and anti-beauty ($\bar B$) mesons in proton-proton collisions in the leading order approximation of the parton Reggeization approach consistently merged with the next-to-leading order corrections from the emission of additional hard gluon. To describe b-quark hadronization we use the universal scale-depended parton-to-meson fragmentation functions extracted from the world $e^+e^-$ annihilation data. We have obtained good agreement between our predictions and data from the CMS Collaboration at the energy $\sqrt{S}=7$ TeV for $B \bar B$ angular correlations within uncertainties and without free parameters. Predictions for analogous correlation observables at $\sqrt{S}=13$ TeV are provided.
2304.06010
Mikael Mieskolainen
Mikael Mieskolainen
GRANIITTI: towards a deep learning-enhanced Monte Carlo event generator for high-energy diffraction
Diffraction and Low-x 2022 proceedings (Acta Phys. Pol. B), 6 pages, 5 figures
null
null
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We introduce GRANIITTI, a new Monte Carlo event generator designed especially to solve the enigma of glueballs at the LHC. We discuss the available physics processes, compare the simulations against STAR data from RHIC and span ambitious future directions towards the first diffractive event generator with a deep learning-enhanced computational engine.
[ { "created": "Wed, 12 Apr 2023 17:34:36 GMT", "version": "v1" } ]
2023-04-13
[ [ "Mieskolainen", "Mikael", "" ] ]
We introduce GRANIITTI, a new Monte Carlo event generator designed especially to solve the enigma of glueballs at the LHC. We discuss the available physics processes, compare the simulations against STAR data from RHIC and span ambitious future directions towards the first diffractive event generator with a deep learning-enhanced computational engine.
0908.2567
Schoeffel Laurent
Laurent Schoeffel (CEA Saclay, Irfu/SPP)
Understanding the structure of the proton at the LHC
3 pages, 1 figure, proceedings of the 2009 Europhysics Conference on High Energy Physics, 16-22 July 2009 Krakow, Poland
PoS EPS-HEP2009 2009:381,2009
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Understanding the fundamental structure of matter requires an understanding of how quarks and gluons are assembled to form hadrons and of the structure of the protons which are the colliding particles at LHC. The arrangement of quarks and gluons inside nucleons can be probed by accelerating electrons, hadrons or nuclei to precisely controlled energies, smashing them into a target nucleus and examining in detail the final products. The LHC physics program is rich and has been widely described. It encompasses the searches for new particles up to masses of several TeV, including the elucidation of electroweak symmetry breaking and the possible observation of new symmetries at higher scales, and precision measurements of fundamental parameters in the electroweak and strong gauge sectors. Obviously, this program requires a precise understanding of the structure of the proton in terms of quarks and gluons, obtained from HERA and Tevatron. However, the knowledge on parton distribution functions (PDFs) is still limited for many aspects of LHC physics and the discovery potential is thus reduced. In this proceeding, we show on one example that it is possible to find some observables less sensitive to PDF uncertainties to probe with a high efficency new physics beyond the standard model.
[ { "created": "Tue, 18 Aug 2009 13:25:59 GMT", "version": "v1" } ]
2014-11-20
[ [ "Schoeffel", "Laurent", "", "CEA Saclay, Irfu/SPP" ] ]
Understanding the fundamental structure of matter requires an understanding of how quarks and gluons are assembled to form hadrons and of the structure of the protons which are the colliding particles at LHC. The arrangement of quarks and gluons inside nucleons can be probed by accelerating electrons, hadrons or nuclei to precisely controlled energies, smashing them into a target nucleus and examining in detail the final products. The LHC physics program is rich and has been widely described. It encompasses the searches for new particles up to masses of several TeV, including the elucidation of electroweak symmetry breaking and the possible observation of new symmetries at higher scales, and precision measurements of fundamental parameters in the electroweak and strong gauge sectors. Obviously, this program requires a precise understanding of the structure of the proton in terms of quarks and gluons, obtained from HERA and Tevatron. However, the knowledge on parton distribution functions (PDFs) is still limited for many aspects of LHC physics and the discovery potential is thus reduced. In this proceeding, we show on one example that it is possible to find some observables less sensitive to PDF uncertainties to probe with a high efficency new physics beyond the standard model.
2008.02095
Subhasmita Mishra
Subhasmita Mishra
Neutrino mixing and Leptogenesis with modular $S_3$ symmetry in the framework of type III seesaw
18 pages, 6 figures
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Discrete symmetries being preferred to explain the neutrino phenomenology, we chose the simplest $S_3$ group and explore the implication of its modular form on neutrino masses and mixing. Non-trivial transformations of Yukawa couplings under this symmetry, make the model phenomenologically interesting by reducing the requirement of multiple scalar fields. This symmetry imposes a specific flavor structure to the neutrino mass matrix within the framework of less frequented type III seesaw mechanism and helps to explore the neutrino mixing consistent with the current observation. Apart, we also explain the preferred scenario of leptogenesis to explain the baryon asymmetry of the universe by generating the lepton asymmetry from the decay of heavy fermion triplet at TeV scale.
[ { "created": "Wed, 5 Aug 2020 12:56:14 GMT", "version": "v1" } ]
2020-08-06
[ [ "Mishra", "Subhasmita", "" ] ]
Discrete symmetries being preferred to explain the neutrino phenomenology, we chose the simplest $S_3$ group and explore the implication of its modular form on neutrino masses and mixing. Non-trivial transformations of Yukawa couplings under this symmetry, make the model phenomenologically interesting by reducing the requirement of multiple scalar fields. This symmetry imposes a specific flavor structure to the neutrino mass matrix within the framework of less frequented type III seesaw mechanism and helps to explore the neutrino mixing consistent with the current observation. Apart, we also explain the preferred scenario of leptogenesis to explain the baryon asymmetry of the universe by generating the lepton asymmetry from the decay of heavy fermion triplet at TeV scale.
1407.3735
Ayse Kucukarslan
A. Kucukarslan, U.Ozdem and A. Ozpineci
Isovector axial vector and pseudoscalar transition form factors of $\Delta $ in QCD
9 pages, 9 figures. arXiv admin note: text overlap with arXiv:1405.5339
Phys. Rev. D90, 054002, 2014
10.1103/PhysRevD.90.054002
null
hep-ph
http://creativecommons.org/licenses/by/3.0/
We investigate the isovector axial vector and pseudoscalar form factors of $\Delta$ baryon by employing light-cone QCD sum rules. Numerical calculations show that the form factors can be well fitted by the exponential form. We make a comparison with the predictions of Lattice QCD, Chiral Perturbation Theory and Quark Model.
[ { "created": "Mon, 14 Jul 2014 17:25:22 GMT", "version": "v1" }, { "created": "Wed, 10 Dec 2014 13:19:25 GMT", "version": "v2" } ]
2015-06-22
[ [ "Kucukarslan", "A.", "" ], [ "Ozdem", "U.", "" ], [ "Ozpineci", "A.", "" ] ]
We investigate the isovector axial vector and pseudoscalar form factors of $\Delta$ baryon by employing light-cone QCD sum rules. Numerical calculations show that the form factors can be well fitted by the exponential form. We make a comparison with the predictions of Lattice QCD, Chiral Perturbation Theory and Quark Model.
hep-ph/0607143
Drago Alessandro
Marco Contalbrigo, Alessandro Drago and Paolo Lenisa (Ferrara U. & INFN, Ferrara, Italy)
Polarized sea measurements at JPARC
4 pages, 2 figures, Proceedings of DIS2006, Kyoto 2006
null
10.1142/9789812706706_0170
null
hep-ph
null
Large double spin-asymmetries can be foreseen for Drell-Yan production in $p p$ scattering at JPARC energies. The sign of the asymmetries can be used to discriminate between different model calculations of sea quark distributions.
[ { "created": "Wed, 12 Jul 2006 17:41:43 GMT", "version": "v1" } ]
2017-08-23
[ [ "Contalbrigo", "Marco", "", "Ferrara U. &\n INFN, Ferrara, Italy" ], [ "Drago", "Alessandro", "", "Ferrara U. &\n INFN, Ferrara, Italy" ], [ "Lenisa", "Paolo", "", "Ferrara U. &\n INFN, Ferrara, Italy" ] ]
Large double spin-asymmetries can be foreseen for Drell-Yan production in $p p$ scattering at JPARC energies. The sign of the asymmetries can be used to discriminate between different model calculations of sea quark distributions.
hep-ph/9812456
Alessandro Papa
V.S. Fadin, R. Fiore and A. Papa
The quark part of the non-forward BFKL kernel and the ``bootstrap'' for the gluon Reggeization
26 pages, LaTeX, uses axodraw.sty; revised final comment; to appear on Phys. Rev. D
Phys. Rev. D 60, 074025 (1999)
10.1103/PhysRevD.60.074025
UNICAL-TP 98/7, BUDKERINP/98-94
hep-ph
null
We calculate the quark part of the kernel of the generalized non-forward BFKL equation at non-zero momentum transfer $t$ in the next-to-leading logarithmic approximation. Along with the quark contribution to the gluon Regge trajectory, this part includes pieces coming from the quark-antiquark production and from the quark contribution to the radiative corrections in one-gluon production in the Reggeon-Reggeon collisions. The results obtained can be used for an arbitrary representation of the colour group in the $t-$channel. Using the results for the adjoint representation, we demonstrate explicitly the fulfillment of the ``bootstrap'' condition for the gluon Reggeization in the next-to-leading logarithmic approximation in the part concerning the quark contribution.
[ { "created": "Mon, 21 Dec 1998 12:11:05 GMT", "version": "v1" }, { "created": "Wed, 9 Jun 1999 17:53:21 GMT", "version": "v2" } ]
2016-08-25
[ [ "Fadin", "V. S.", "" ], [ "Fiore", "R.", "" ], [ "Papa", "A.", "" ] ]
We calculate the quark part of the kernel of the generalized non-forward BFKL equation at non-zero momentum transfer $t$ in the next-to-leading logarithmic approximation. Along with the quark contribution to the gluon Regge trajectory, this part includes pieces coming from the quark-antiquark production and from the quark contribution to the radiative corrections in one-gluon production in the Reggeon-Reggeon collisions. The results obtained can be used for an arbitrary representation of the colour group in the $t-$channel. Using the results for the adjoint representation, we demonstrate explicitly the fulfillment of the ``bootstrap'' condition for the gluon Reggeization in the next-to-leading logarithmic approximation in the part concerning the quark contribution.
1208.5320
Aiichi Iwazaki
Aiichi Iwazaki
Anomalous Gluon Production and Condensation in Glasma
9 pages, 2figures To be published in Phys. Rev. C
null
10.1103/PhysRevC.87.024903
Nisho-4-2012
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The collinear color electric and magnetic fields have been discussed to be produced immediately after high energy heavy ion collisions. We discuss anomalous gluon production under the background gauge fields. The gluons are Nielsen-Olesen unstable modes. The production rate of the modes by Schwinger mechanism has recently been found to be anomalously larger than the rate of quarks or other stable gluons. Analyzing classical evolutions of the modes with initial conditions given by vacuum fluctuations, we find that their production makes the color electric field decay very rapidly. The life time of the field is approximately given by the inverse of saturation momentum in the collisions. We also show that the mode with zero momentum form a Bose condensate and its gluon number density grows up to be of the order of $1/\alpha_g$. After the saturation of the gluon number density, the condensate melts into quark gluon plasma owing to nonlinear interactions in QCD.
[ { "created": "Mon, 27 Aug 2012 08:08:41 GMT", "version": "v1" }, { "created": "Fri, 18 Jan 2013 02:38:33 GMT", "version": "v2" } ]
2015-06-11
[ [ "Iwazaki", "Aiichi", "" ] ]
The collinear color electric and magnetic fields have been discussed to be produced immediately after high energy heavy ion collisions. We discuss anomalous gluon production under the background gauge fields. The gluons are Nielsen-Olesen unstable modes. The production rate of the modes by Schwinger mechanism has recently been found to be anomalously larger than the rate of quarks or other stable gluons. Analyzing classical evolutions of the modes with initial conditions given by vacuum fluctuations, we find that their production makes the color electric field decay very rapidly. The life time of the field is approximately given by the inverse of saturation momentum in the collisions. We also show that the mode with zero momentum form a Bose condensate and its gluon number density grows up to be of the order of $1/\alpha_g$. After the saturation of the gluon number density, the condensate melts into quark gluon plasma owing to nonlinear interactions in QCD.
1012.4260
Eliecer Hernandez-Gajate
E. Hern\'andez, J. Nieves, M. Valverde and M.J. Vicente-Vacas
New determination of the $N$-$\Delta(1232)$ axial form factors from weak pion production and coherent pion production off nuclei at T2K and MiniBooNE energies revisited
3 latex pages, 1 figure. Talk given at the NuFact10 Conference
null
10.1063/1.3644297
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We re-evaluate our model predictions in Phys. Rev. D 79, 013002 (2009) for different observables in neutrino induced coherent pion production. This comes as a result of the new improved fit to old bubble chamber data of the dominant axial C_5^A nucleon-to-Delta form factor. We find an increase of 20%-30% in the values for the total cross sections. Uncertainties induced by the errors in the determination of C_5^A are computed. Our new results turn out to be compatible within about $1\sigma$ with the former ones. We also stress the existing tension between the recent experimental determination of the \sigma(CC coh \pi^+)}/\sigma(NC coh \pi^0)} $ ratio by the SciBooNE Collaboration and the theoretical predictions.
[ { "created": "Mon, 20 Dec 2010 08:23:06 GMT", "version": "v1" } ]
2015-05-20
[ [ "Hernández", "E.", "" ], [ "Nieves", "J.", "" ], [ "Valverde", "M.", "" ], [ "Vicente-Vacas", "M. J.", "" ] ]
We re-evaluate our model predictions in Phys. Rev. D 79, 013002 (2009) for different observables in neutrino induced coherent pion production. This comes as a result of the new improved fit to old bubble chamber data of the dominant axial C_5^A nucleon-to-Delta form factor. We find an increase of 20%-30% in the values for the total cross sections. Uncertainties induced by the errors in the determination of C_5^A are computed. Our new results turn out to be compatible within about $1\sigma$ with the former ones. We also stress the existing tension between the recent experimental determination of the \sigma(CC coh \pi^+)}/\sigma(NC coh \pi^0)} $ ratio by the SciBooNE Collaboration and the theoretical predictions.
hep-ph/9910309
Anton Rebhan
J.-P. Blaizot, E. Iancu, A. Rebhan
Self-consistent hard-thermal-loop thermodynamics for the quark-gluon plasma
13 pages, 4 figures, LATEX file using elsart.sty; v2: minor rewording in introduction, obvious sign error corrected in sect. 4
Phys.Lett.B470:181-188,1999
10.1016/S0370-2693(99)01306-4
SACLAY-T99/113, CERN-TH/99-307, TUW-99/21
hep-ph hep-lat
null
Self-consistent approximations allowing the calculation of the entropy and the baryon density of a quark-gluon plasma are presented. These approximations incorporate the essential physics of the hard thermal loops, involve only ultraviolet-finite quantities, and are free from overcounting ambiguities. While being nonperturbative in the strong coupling constant $g$, agreement with ordinary perturbation theory is achieved up to and including order $g^3$. It is shown how the pressure can be reconstructed from the entropy and the baryon density taking into account the scale anomaly. The results obtained are in good agreement with available lattice data down to temperatures of about twice the critical temperature.
[ { "created": "Tue, 12 Oct 1999 13:49:05 GMT", "version": "v1" }, { "created": "Wed, 3 Nov 1999 19:48:52 GMT", "version": "v2" } ]
2008-11-26
[ [ "Blaizot", "J. -P.", "" ], [ "Iancu", "E.", "" ], [ "Rebhan", "A.", "" ] ]
Self-consistent approximations allowing the calculation of the entropy and the baryon density of a quark-gluon plasma are presented. These approximations incorporate the essential physics of the hard thermal loops, involve only ultraviolet-finite quantities, and are free from overcounting ambiguities. While being nonperturbative in the strong coupling constant $g$, agreement with ordinary perturbation theory is achieved up to and including order $g^3$. It is shown how the pressure can be reconstructed from the entropy and the baryon density taking into account the scale anomaly. The results obtained are in good agreement with available lattice data down to temperatures of about twice the critical temperature.
1405.7370
Jesse Thaler
Kaustubh Agashe, Yanou Cui, Lina Necib, Jesse Thaler
(In)direct Detection of Boosted Dark Matter
40 pages, 11 figures, 1 table; v2: references added, appendix B revised; v3: improved presentation of signal/background, added section 4.4 on earth attenuation, version to appear in JCAP; v4: typos fixed, appendix B bounds weakened, conclusions unchanged
null
10.1088/1475-7516/2014/10/062
MIT-CTP 4538, UMD-PP-014-005
hep-ph astro-ph.CO hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We initiate the study of novel thermal dark matter (DM) scenarios where present-day annihilation of DM in the galactic center produces boosted stable particles in the dark sector. These stable particles are typically a subdominant DM component, but because they are produced with a large Lorentz boost in this process, they can be detected in large volume terrestrial experiments via neutral-current-like interactions with electrons or nuclei. This novel DM signal thus combines the production mechanism associated with indirect detection experiments (i.e. galactic DM annihilation) with the detection mechanism associated with direct detection experiments (i.e. DM scattering off terrestrial targets). Such processes are generically present in multi-component DM scenarios or those with non-minimal DM stabilization symmetries. As a proof of concept, we present a model of two-component thermal relic DM, where the dominant heavy DM species has no tree-level interactions with the standard model and thus largely evades direct and indirect DM bounds. Instead, its thermal relic abundance is set by annihilation into a subdominant lighter DM species, and the latter can be detected in the boosted channel via the same annihilation process occurring today. Especially for dark sector masses in the 10 MeV-10 GeV range, the most promising signals are electron scattering events pointing toward the galactic center. These can be detected in experiments designed for neutrino physics or proton decay, in particular Super-K and its upgrade Hyper-K, as well as the PINGU/MICA extensions of IceCube. This boosted DM phenomenon highlights the distinctive signatures possible from non-minimal dark sectors.
[ { "created": "Wed, 28 May 2014 20:00:19 GMT", "version": "v1" }, { "created": "Wed, 18 Jun 2014 20:56:07 GMT", "version": "v2" }, { "created": "Sat, 18 Oct 2014 03:09:33 GMT", "version": "v3" }, { "created": "Wed, 31 Dec 2014 21:48:51 GMT", "version": "v4" } ]
2015-06-19
[ [ "Agashe", "Kaustubh", "" ], [ "Cui", "Yanou", "" ], [ "Necib", "Lina", "" ], [ "Thaler", "Jesse", "" ] ]
We initiate the study of novel thermal dark matter (DM) scenarios where present-day annihilation of DM in the galactic center produces boosted stable particles in the dark sector. These stable particles are typically a subdominant DM component, but because they are produced with a large Lorentz boost in this process, they can be detected in large volume terrestrial experiments via neutral-current-like interactions with electrons or nuclei. This novel DM signal thus combines the production mechanism associated with indirect detection experiments (i.e. galactic DM annihilation) with the detection mechanism associated with direct detection experiments (i.e. DM scattering off terrestrial targets). Such processes are generically present in multi-component DM scenarios or those with non-minimal DM stabilization symmetries. As a proof of concept, we present a model of two-component thermal relic DM, where the dominant heavy DM species has no tree-level interactions with the standard model and thus largely evades direct and indirect DM bounds. Instead, its thermal relic abundance is set by annihilation into a subdominant lighter DM species, and the latter can be detected in the boosted channel via the same annihilation process occurring today. Especially for dark sector masses in the 10 MeV-10 GeV range, the most promising signals are electron scattering events pointing toward the galactic center. These can be detected in experiments designed for neutrino physics or proton decay, in particular Super-K and its upgrade Hyper-K, as well as the PINGU/MICA extensions of IceCube. This boosted DM phenomenon highlights the distinctive signatures possible from non-minimal dark sectors.
hep-ph/9808228
Thomas Gutsche
M. Strohmeier-Presicek, T. Gutsche, A. Faessler and R. Vinh Mau
$4\pi$ Decay Modes of the $f_0(1500)$ Resonance
11 pages, 1 figure
Phys.Lett.B438:21-26,1998
10.1016/S0370-2693(98)01044-2
null
hep-ph
null
We investigate the two-body decay modes $\rho\rho, \pi\pi^{\ast}(1300)$ and $\sigma \sigma$ of the $f_0(1500)$, all leading to the $4\pi$ decay channel, in a three-state mixing scheme, where the $f_0(1500)$ is a mixture of the lowest-lying scalar glueball with the nearby isoscalar states of the $0^{++} Q\bar{Q}$ nonet. In the leading order of this scheme, the decay mechanism of the $f_0(1500)$ proceeds dominantly via its quarkonia components, which can be described in the framework of the $^3P_0$ $Q\bar Q$ pair creation model. We predict the hierarchy of decay branching ratios B with $B(\rho \rho) ^{>}_{\sim} B(\pi\pi) ^{>}_{\sim} B(\sigma \sigma) > B(\pi\pi^{\ast})$, providing a key signature for the proposed mixing scheme in this leading order approach.
[ { "created": "Wed, 5 Aug 1998 08:29:27 GMT", "version": "v1" } ]
2008-11-26
[ [ "Strohmeier-Presicek", "M.", "" ], [ "Gutsche", "T.", "" ], [ "Faessler", "A.", "" ], [ "Mau", "R. Vinh", "" ] ]
We investigate the two-body decay modes $\rho\rho, \pi\pi^{\ast}(1300)$ and $\sigma \sigma$ of the $f_0(1500)$, all leading to the $4\pi$ decay channel, in a three-state mixing scheme, where the $f_0(1500)$ is a mixture of the lowest-lying scalar glueball with the nearby isoscalar states of the $0^{++} Q\bar{Q}$ nonet. In the leading order of this scheme, the decay mechanism of the $f_0(1500)$ proceeds dominantly via its quarkonia components, which can be described in the framework of the $^3P_0$ $Q\bar Q$ pair creation model. We predict the hierarchy of decay branching ratios B with $B(\rho \rho) ^{>}_{\sim} B(\pi\pi) ^{>}_{\sim} B(\sigma \sigma) > B(\pi\pi^{\ast})$, providing a key signature for the proposed mixing scheme in this leading order approach.
hep-ph/9902312
Peres Orlando Luis Goulart
O.L.G. Peres and A.Y. Smirnov
Testing the Solar Neutrino Conversion with Atmospheric Neutrinos
Latex, 24 pages 5 PS figures, Minor changes, typos corrected
Phys.Lett. B456 (1999) 204-213
10.1016/S0370-2693(99)00487-6
null
hep-ph hep-ex
null
Neutrino oscillations with parameters relevant for the large mixing solution of the solar neutrino problem ($\Delta m^2_{21} = (2 - 20) \cdot 10^{-5}$ eV$^2$, $\sin^2 2\theta_{12} > 0.65$) can lead to observable (up to 10 - 12 %) excess of the e-like events in the sub-GeV atmospheric neutrino sample. The excess has a weak zenith angle dependence in the low energy part of the sample and strong zenith angle dependence in the high energy part. The effect rapidly decreases with energy of neutrinos, it is suppressed in the multi-GeV sample. These signatures allow to disentangle the effect from other possible explanations of the excess. The possibility of change of the sign of the up-down asymmetry of the excess with energy (positive in the sub-GeV region and negative in the multi-GeV region) is marked. The predicted properties of excess are in agreement with SuperKamiokande data.
[ { "created": "Thu, 11 Feb 1999 00:10:17 GMT", "version": "v1" }, { "created": "Fri, 12 Feb 1999 22:57:25 GMT", "version": "v2" } ]
2009-10-31
[ [ "Peres", "O. L. G.", "" ], [ "Smirnov", "A. Y.", "" ] ]
Neutrino oscillations with parameters relevant for the large mixing solution of the solar neutrino problem ($\Delta m^2_{21} = (2 - 20) \cdot 10^{-5}$ eV$^2$, $\sin^2 2\theta_{12} > 0.65$) can lead to observable (up to 10 - 12 %) excess of the e-like events in the sub-GeV atmospheric neutrino sample. The excess has a weak zenith angle dependence in the low energy part of the sample and strong zenith angle dependence in the high energy part. The effect rapidly decreases with energy of neutrinos, it is suppressed in the multi-GeV sample. These signatures allow to disentangle the effect from other possible explanations of the excess. The possibility of change of the sign of the up-down asymmetry of the excess with energy (positive in the sub-GeV region and negative in the multi-GeV region) is marked. The predicted properties of excess are in agreement with SuperKamiokande data.
1407.4889
Yonglu Liu
Yong-Lu Liu, Chun-Yu Cui, and Ming-Qiu Huang
Higher order light-cone distribution amplitudes of the Lambda baryon
17pages,10figures. arXiv admin note: text overlap with arXiv:1311.5960
Eur. Phys. J. C (2014) 74:3041
10.1140/epjc/s10052-014-3041-x
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The improved light-cone distribution amplitudes (LCDAs) of the $\Lambda$ baryon are examined on the basis of the QCD conformal partial wave expansion approach. The calculations are carried out to the next-to-leading order of conformal spin accuracy with consideration of twist 6. The next leading order conformal expansion coefficients are related to the nonperturbative parameters defined by the local three quark operator matrix elements with different Lorentz structures with a covariant derivative. The nonperturbative parameters are determined with the QCD sum rule method. The explicit expressions of the LCDAs are provided as the main results.
[ { "created": "Fri, 18 Jul 2014 05:36:30 GMT", "version": "v1" }, { "created": "Mon, 15 Sep 2014 14:13:46 GMT", "version": "v2" } ]
2014-09-16
[ [ "Liu", "Yong-Lu", "" ], [ "Cui", "Chun-Yu", "" ], [ "Huang", "Ming-Qiu", "" ] ]
The improved light-cone distribution amplitudes (LCDAs) of the $\Lambda$ baryon are examined on the basis of the QCD conformal partial wave expansion approach. The calculations are carried out to the next-to-leading order of conformal spin accuracy with consideration of twist 6. The next leading order conformal expansion coefficients are related to the nonperturbative parameters defined by the local three quark operator matrix elements with different Lorentz structures with a covariant derivative. The nonperturbative parameters are determined with the QCD sum rule method. The explicit expressions of the LCDAs are provided as the main results.
hep-ph/9906237
Giovanni M. Prosperi
G. M. Prosperi
Quark-antiquark Bethe-Salpeter formalism, spectrum and Regge Trajectories
11 pages, 2 figures, conference report: Proc. Int. Conf. on "Problems of Quantum Field Theory", Dubna, July 13-16, 1998
null
null
hpep-ph/9906237
hep-ph
null
Starting from a path integral representation of appropriate 4-point and 2-point gauge invariant Green functions and from the "Modified Area Law" model for the evaluation of the Wilson loop, a q \bar q Bethe-Salpeter like equation and a related Schwinger-Dyson equation can be obtained. From such equations an effective relativistic Hamiltonian can be derived by standard methods and then applied to the determination of the meson spectrum. The entire known heavy-heavy and heavy-light spectra and the lowest light-light Regge trajectories are rather well reproduced in terms of four parameters alone, the light quark masses being fixed a priori on typical current values.
[ { "created": "Thu, 3 Jun 1999 17:00:31 GMT", "version": "v1" } ]
2007-05-23
[ [ "Prosperi", "G. M.", "" ] ]
Starting from a path integral representation of appropriate 4-point and 2-point gauge invariant Green functions and from the "Modified Area Law" model for the evaluation of the Wilson loop, a q \bar q Bethe-Salpeter like equation and a related Schwinger-Dyson equation can be obtained. From such equations an effective relativistic Hamiltonian can be derived by standard methods and then applied to the determination of the meson spectrum. The entire known heavy-heavy and heavy-light spectra and the lowest light-light Regge trajectories are rather well reproduced in terms of four parameters alone, the light quark masses being fixed a priori on typical current values.
1211.5160
Sarah Andreas
Sarah Andreas
Update on Hidden Sectors with Dark Forces and Dark Matter
4 pages, 3 figures, contribution to the proceedings of the "8th Patras Workshop on Axions, WIMPs and WISPs", Chicago USA, 18 - 22 July 2012
null
null
DESY 12-217
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Recently there has been much interest in hidden sectors, especially in the context of dark matter and dark forces, since they are a common feature of beyond standard model scenarios like string theory and SUSY and additionally exhibit interesting phenomenological aspects. Various laboratory experiments place limits on the so-called hidden photon and continuously further probe and constrain the parameter space; an updated overview is presented here. Furthermore, for several hidden sector models with light dark matter we study the viability with respect to the relic abundance and direct detection experiments.
[ { "created": "Wed, 21 Nov 2012 22:06:06 GMT", "version": "v1" } ]
2012-11-26
[ [ "Andreas", "Sarah", "" ] ]
Recently there has been much interest in hidden sectors, especially in the context of dark matter and dark forces, since they are a common feature of beyond standard model scenarios like string theory and SUSY and additionally exhibit interesting phenomenological aspects. Various laboratory experiments place limits on the so-called hidden photon and continuously further probe and constrain the parameter space; an updated overview is presented here. Furthermore, for several hidden sector models with light dark matter we study the viability with respect to the relic abundance and direct detection experiments.
2304.11844
Debasish Borah
Debasish Borah, Suruj Jyoti Das, Rishav Roshan, Rome Samanta
Imprint of PBH domination on gravitational waves generated by cosmic strings
22 pages, 4 captioned figures, matches version accepted for publication in Phys. Rev. D
null
10.1103/PhysRevD.108.023531
null
hep-ph astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the effect of an ultra-light primordial black hole (PBH) dominated phase on the gravitational wave (GW) spectrum generated by a cosmic string (CS) network formed as a result of a high-scale $U(1)$ symmetry breaking. A PBH-dominated phase leads to tilts in the spectrum via entropy dilution and generates a new GW spectrum from PBH density fluctuations, detectable at ongoing and planned near-future GW detectors. The combined spectrum has a unique shape with a plateau, a sharp tilted peak over the plateau, and a characteristic fall-off, which can be distinguished from the one generated in the combination of CS and any other matter domination or new exotic physics. We discuss how ongoing and planned future experiments can probe such a unique spectrum for different values of $U(1)$ breaking scale and PBH parameters such as initial mass and energy fraction.
[ { "created": "Mon, 24 Apr 2023 06:22:31 GMT", "version": "v1" }, { "created": "Fri, 7 Jul 2023 05:08:42 GMT", "version": "v2" } ]
2023-08-09
[ [ "Borah", "Debasish", "" ], [ "Das", "Suruj Jyoti", "" ], [ "Roshan", "Rishav", "" ], [ "Samanta", "Rome", "" ] ]
We study the effect of an ultra-light primordial black hole (PBH) dominated phase on the gravitational wave (GW) spectrum generated by a cosmic string (CS) network formed as a result of a high-scale $U(1)$ symmetry breaking. A PBH-dominated phase leads to tilts in the spectrum via entropy dilution and generates a new GW spectrum from PBH density fluctuations, detectable at ongoing and planned near-future GW detectors. The combined spectrum has a unique shape with a plateau, a sharp tilted peak over the plateau, and a characteristic fall-off, which can be distinguished from the one generated in the combination of CS and any other matter domination or new exotic physics. We discuss how ongoing and planned future experiments can probe such a unique spectrum for different values of $U(1)$ breaking scale and PBH parameters such as initial mass and energy fraction.
2310.07553
Xiangyang Ju
Tuan Minh Pham, Xiangyang Ju
Simulation of Hadronic Interactions with Deep Generative Models
7 pages, 5 figures, Proceeding of 26th International Conference On Computing High Energy & Nuclear Physics (CHEP 2023)
null
null
null
hep-ph hep-ex
http://creativecommons.org/licenses/by-nc-sa/4.0/
Accurate simulation of detector responses to hadrons is paramount for all physics programs at the Large Hadron Collider (LHC). Central to this simulation is the modeling of hadronic interactions. Unfortunately, the absence of first-principle theoretical guidance has made this a formidable challenge. The state-of-the-art simulation tool, \textsc{Geant4}, currently relies on phenomenology-inspired parametric models. Each model is designed to simulate hadronic interactions within specific energy ranges and for particular types of hadrons. Despite dedicated tuning efforts, these models sometimes fail to describe the data in certain physics processes accurately. Furthermore, fine-tuning these models with new measurements is laborious. Our research endeavors to leverage generative models to simulate hadronic interactions. While our ultimate goal is to train a generative model using experimental data, we have taken a crucial step by training conditional normalizing flow models with \textsc{Geant4} simulation data. Our work marks a significant stride toward developing a fully differentiable and data-driven model for hadronic interactions in High Energy and Nuclear Physics.
[ { "created": "Wed, 11 Oct 2023 14:57:03 GMT", "version": "v1" } ]
2023-10-12
[ [ "Pham", "Tuan Minh", "" ], [ "Ju", "Xiangyang", "" ] ]
Accurate simulation of detector responses to hadrons is paramount for all physics programs at the Large Hadron Collider (LHC). Central to this simulation is the modeling of hadronic interactions. Unfortunately, the absence of first-principle theoretical guidance has made this a formidable challenge. The state-of-the-art simulation tool, \textsc{Geant4}, currently relies on phenomenology-inspired parametric models. Each model is designed to simulate hadronic interactions within specific energy ranges and for particular types of hadrons. Despite dedicated tuning efforts, these models sometimes fail to describe the data in certain physics processes accurately. Furthermore, fine-tuning these models with new measurements is laborious. Our research endeavors to leverage generative models to simulate hadronic interactions. While our ultimate goal is to train a generative model using experimental data, we have taken a crucial step by training conditional normalizing flow models with \textsc{Geant4} simulation data. Our work marks a significant stride toward developing a fully differentiable and data-driven model for hadronic interactions in High Energy and Nuclear Physics.
1505.03706
Sandro Uccirati
Margherita Ghezzi, Raquel Gomez-Ambrosio, Giampiero Passarino and Sandro Uccirati
NLO Higgs Effective Field Theory and kappa-framework
33 pages + appendices
null
10.1007/JHEP07(2015)175
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A consistent framework for studying Standard Model deviations is developed. It assumes that New Physics becomes relevant at some scale beyond the present experimental reach and uses the Effective Field Theory approach by adding higher-dimensional operators to the Standard Model Lagrangian and by computing relevant processes at the next-to-leading order, extending the original kappa-framework.
[ { "created": "Thu, 14 May 2015 12:47:57 GMT", "version": "v1" } ]
2015-09-02
[ [ "Ghezzi", "Margherita", "" ], [ "Gomez-Ambrosio", "Raquel", "" ], [ "Passarino", "Giampiero", "" ], [ "Uccirati", "Sandro", "" ] ]
A consistent framework for studying Standard Model deviations is developed. It assumes that New Physics becomes relevant at some scale beyond the present experimental reach and uses the Effective Field Theory approach by adding higher-dimensional operators to the Standard Model Lagrangian and by computing relevant processes at the next-to-leading order, extending the original kappa-framework.
2202.11497
Alexander Ilyichev Dr.
A. Afanasev, A. Ilyichev
Charge-asymmetric correlations in elastic lepton- and antilepton-proton scattering from real photon emission
17 pages, 7 figures
Eur.Phys.J. A (2022) 59:156
10.1140/epja/s10050-022-00805-8
null
hep-ph
http://creativecommons.org/publicdomain/zero/1.0/
Observation of charge asymmetry by comparing electron and positron, or muon and anti-muon, scattering on a hadronic target presently serves as an experimental tool to study two-photon exchange effects. In addition to two-photon exchange, real photon emission also contributes to the charge asymmetry. We present a theoretical formalism, explicit expressions, and a numerical analysis of hard photon emission for the charge asymmetry in lepton- and antilepton-proton scattering. Different kinematic conditions are considered, namely, either fixed transferred momentum squared or a fixed lepton scattering angle. The infrared divergence from real photon emission is treated by the Bardin-Shumeiko technique and canceled with the soft part of the two-photon exchange contribution extracted and calculated using Tsai approach. All final expressions are obtained beyond the ultrarelativistic approximation with respect to the lepton mass that allows to evaluate numerically of the considered effects not only for ultrarelativistic leptons (JLab) and but for moderately relativistic (MUSE) kinematics, too.
[ { "created": "Wed, 23 Feb 2022 13:29:50 GMT", "version": "v1" }, { "created": "Sat, 3 Sep 2022 08:31:08 GMT", "version": "v2" } ]
2022-09-07
[ [ "Afanasev", "A.", "" ], [ "Ilyichev", "A.", "" ] ]
Observation of charge asymmetry by comparing electron and positron, or muon and anti-muon, scattering on a hadronic target presently serves as an experimental tool to study two-photon exchange effects. In addition to two-photon exchange, real photon emission also contributes to the charge asymmetry. We present a theoretical formalism, explicit expressions, and a numerical analysis of hard photon emission for the charge asymmetry in lepton- and antilepton-proton scattering. Different kinematic conditions are considered, namely, either fixed transferred momentum squared or a fixed lepton scattering angle. The infrared divergence from real photon emission is treated by the Bardin-Shumeiko technique and canceled with the soft part of the two-photon exchange contribution extracted and calculated using Tsai approach. All final expressions are obtained beyond the ultrarelativistic approximation with respect to the lepton mass that allows to evaluate numerically of the considered effects not only for ultrarelativistic leptons (JLab) and but for moderately relativistic (MUSE) kinematics, too.
1208.5470
Francois Fillion-Gourdeau
Fran\c{c}ois Fillion-Gourdeau, Emmanuel Lorin and Andr\'e D. Bandrauk
Resonantly enhanced pair production in a simple diatomic model
11 pages, 4 figures
Phys. Rev. Lett. 110, 013002 (2013)
10.1103/PhysRevLett.110.013002
null
hep-ph physics.atom-ph quant-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A new mechanism for the production of electron-positron pairs from the interaction of a laser field and a fully stripped diatomic molecule in the tunneling regime is presented. When the laser field is turned off, the Dirac operator has resonances in both the positive and the negative energy continua while bound states are in the mass gap. When this system is immersed in a strong laser field, the resonances move in the complex energy plane: the negative energy resonances are pushed to higher energies while the bound states are Stark shifted. It is argued here that there is a pair production enhancement at the crossing of resonances by looking at a simple 1-D model: the nuclei are modeled simply by Dirac delta potential wells while the laser field is assumed to be static and of finite spatial extent. The average rate for the number of electron-positron pairs produced is evaluated and the results are compared to the single nucleus and to the free cases. It is shown that positrons are produced by the Resonantly Enhanced Pair Production (REPP) mechanism, which is analogous to the resonantly enhanced ionization of molecular physics. This phenomenon could be used to increase the number of pairs produced at low field strength, allowing the study of the Dirac vacuum.
[ { "created": "Mon, 27 Aug 2012 19:17:52 GMT", "version": "v1" } ]
2013-03-18
[ [ "Fillion-Gourdeau", "François", "" ], [ "Lorin", "Emmanuel", "" ], [ "Bandrauk", "André D.", "" ] ]
A new mechanism for the production of electron-positron pairs from the interaction of a laser field and a fully stripped diatomic molecule in the tunneling regime is presented. When the laser field is turned off, the Dirac operator has resonances in both the positive and the negative energy continua while bound states are in the mass gap. When this system is immersed in a strong laser field, the resonances move in the complex energy plane: the negative energy resonances are pushed to higher energies while the bound states are Stark shifted. It is argued here that there is a pair production enhancement at the crossing of resonances by looking at a simple 1-D model: the nuclei are modeled simply by Dirac delta potential wells while the laser field is assumed to be static and of finite spatial extent. The average rate for the number of electron-positron pairs produced is evaluated and the results are compared to the single nucleus and to the free cases. It is shown that positrons are produced by the Resonantly Enhanced Pair Production (REPP) mechanism, which is analogous to the resonantly enhanced ionization of molecular physics. This phenomenon could be used to increase the number of pairs produced at low field strength, allowing the study of the Dirac vacuum.
1409.8393
Shoaib Munir
Nils-Erik Bomark, Stefano Moretti, Shoaib Munir and Leszek Roszkowski
A light NMSSM pseudoscalar Higgs boson at the LHC redux
33 pages, 13 figures. Typos corrected, figures and some text improved, references added. Version to appear in JHEP
JHEP 1502 (2015) 044
10.1007/JHEP02(2015)044
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Next-to-Minimal Supersymmetric Standard Model (NMSSM) contains a singlet-like pseudoscalar Higgs boson in addition to the doublet-like pseudoscalar of the Minimal Supersymmetric Standard Model. This new pseudoscalar can have a very low mass without violating the LEP exclusion constraints and it can potentially provide a hallmark signature of non-minimal supersymmetry at the LHC. In this analysis we revisit the light pseudoscalar in the NMSSM with partial universality at some high unification scale. We delineate the regions of the model's parameter space that are consistent with the up-to-date theoretical and experimental constraints, from both Higgs boson searches and elsewhere (most notably $b$-physics), and examine to what extent they can be probed by the LHC. To this end we review the most important production channels of such a Higgs state and assess the scope of its observation at the forthcoming Run-2 of the LHC. We conclude that the $b\bar{b}$-associated production of the pseudoscalar, which has been emphasised in previous studies, does not carry much promise anymore, given the measured mass of the Higgs boson at the LHC. However, the decays of one of the heavier scalar Higgsbosons of the NMSSM can potentially lead to the discovery of its light pseudoscalar. Especially promising are the decays of one or both of the two lightest scalar states into a pseudoscalar pair and of the heaviest scalar into a pseudoscalar and a $Z$ boson. Since the latter channel has not been explored in detail in the literature so far, we provide details of some benchmark points which can be probed for establishing its signature.
[ { "created": "Tue, 30 Sep 2014 05:58:40 GMT", "version": "v1" }, { "created": "Sat, 14 Feb 2015 06:23:38 GMT", "version": "v2" } ]
2015-02-18
[ [ "Bomark", "Nils-Erik", "" ], [ "Moretti", "Stefano", "" ], [ "Munir", "Shoaib", "" ], [ "Roszkowski", "Leszek", "" ] ]
The Next-to-Minimal Supersymmetric Standard Model (NMSSM) contains a singlet-like pseudoscalar Higgs boson in addition to the doublet-like pseudoscalar of the Minimal Supersymmetric Standard Model. This new pseudoscalar can have a very low mass without violating the LEP exclusion constraints and it can potentially provide a hallmark signature of non-minimal supersymmetry at the LHC. In this analysis we revisit the light pseudoscalar in the NMSSM with partial universality at some high unification scale. We delineate the regions of the model's parameter space that are consistent with the up-to-date theoretical and experimental constraints, from both Higgs boson searches and elsewhere (most notably $b$-physics), and examine to what extent they can be probed by the LHC. To this end we review the most important production channels of such a Higgs state and assess the scope of its observation at the forthcoming Run-2 of the LHC. We conclude that the $b\bar{b}$-associated production of the pseudoscalar, which has been emphasised in previous studies, does not carry much promise anymore, given the measured mass of the Higgs boson at the LHC. However, the decays of one of the heavier scalar Higgsbosons of the NMSSM can potentially lead to the discovery of its light pseudoscalar. Especially promising are the decays of one or both of the two lightest scalar states into a pseudoscalar pair and of the heaviest scalar into a pseudoscalar and a $Z$ boson. Since the latter channel has not been explored in detail in the literature so far, we provide details of some benchmark points which can be probed for establishing its signature.
hep-ph/0006195
Clerbaux Barbara
Barbara Clerbaux
Results on Diffraction at HERA and Tevatron
Results presented at "La Thuile" conference, feb/mar 2000, Italy. To appear in the proceedings. 12 pages, 10 figures
null
null
null
hep-ph
null
Recent results on diffraction at HERA, from the H1 and ZEUS Collaborations, and at Tevatron, from the CDF and D0 Collaborations, are reviewed. The measurement of the diffractive structure function at HERA is presented, and the pomeron structure function is extracted from QCD fits. Diffractive dijet production is given as an example analysis of the diffractive final state. These analysis are consistent with a leading gluon partonic structure for the pomeron. Hard single diffraction, double diffraction and double pomeron exchange processes are studied at the Tevatron and complement the studies performed at HERA. Finally, HERA results on the diffractive (exclusive) production of a vector particle, either a vector meson or a photon, are presented and compared to models based on perturbative QCD.
[ { "created": "Fri, 16 Jun 2000 16:07:03 GMT", "version": "v1" } ]
2007-05-23
[ [ "Clerbaux", "Barbara", "" ] ]
Recent results on diffraction at HERA, from the H1 and ZEUS Collaborations, and at Tevatron, from the CDF and D0 Collaborations, are reviewed. The measurement of the diffractive structure function at HERA is presented, and the pomeron structure function is extracted from QCD fits. Diffractive dijet production is given as an example analysis of the diffractive final state. These analysis are consistent with a leading gluon partonic structure for the pomeron. Hard single diffraction, double diffraction and double pomeron exchange processes are studied at the Tevatron and complement the studies performed at HERA. Finally, HERA results on the diffractive (exclusive) production of a vector particle, either a vector meson or a photon, are presented and compared to models based on perturbative QCD.
hep-ph/9608250
Gavin Salam
G. P. Salam
Unitarity and Saturation in the Dipole Formulation
5 pages LaTeX2e, 2 figures; uses epsfig.sty and procl2e.sty (included). Talk presented at DIS96, International Workshop on Deep Inelastic Scattering and Related Phenomena, Rome. Postscript also available from http://www.hep.phy.cam.ac.uk/theory/papers/
null
null
Cavendish-HEP-96/12
hep-ph
null
This talk reviews briefly some of the main results of the small-x dipole formulation with regards to unitarity corrections. It illustrates the correspondence between unitarity and saturation corrections in the dipole approach and multiple t-channel pomeron exchange in the traditional BFKL view, and discusses how one can estimate and understand the effects of saturation.
[ { "created": "Wed, 7 Aug 1996 14:48:31 GMT", "version": "v1" } ]
2007-05-23
[ [ "Salam", "G. P.", "" ] ]
This talk reviews briefly some of the main results of the small-x dipole formulation with regards to unitarity corrections. It illustrates the correspondence between unitarity and saturation corrections in the dipole approach and multiple t-channel pomeron exchange in the traditional BFKL view, and discusses how one can estimate and understand the effects of saturation.
0912.3430
Chris White
C. Weydert, S. Frixione, M. Herquet, M. Klasen, E. Laenen, T. Plehn, G. Stavenga, C. D. White
Charged Higgs boson production in association with a top quark in MC@NLO
35 pages; 7 figures
Eur.Phys.J.C67:617-636,2010
10.1140/epjc/s10052-010-1320-8
LPSC-09-188, NIKHEF-2009-013, ITFA-2009-21, FERMILAB-PUB-09-626-T, IPPP/09/95, DCPT/09/190, CERN-TH/2009-251, ITF-UU-09/32
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We discuss the calculation of charged Higgs boson production in association with top quark in the MC@NLO framework for combining NLO matrix elements with a parton shower. The process is defined in a model independent manner for wide applicability, and can be used if the charged Higgs boson mass is either greater or less than the mass of the top quark. For the latter mass region, care is needed in defining the charged Higgs production mode due to interference with top pair production. We give a suitable definition applicable in an NLO (plus parton shower) context, and present example results for the LHC.
[ { "created": "Thu, 17 Dec 2009 15:28:44 GMT", "version": "v1" } ]
2014-11-20
[ [ "Weydert", "C.", "" ], [ "Frixione", "S.", "" ], [ "Herquet", "M.", "" ], [ "Klasen", "M.", "" ], [ "Laenen", "E.", "" ], [ "Plehn", "T.", "" ], [ "Stavenga", "G.", "" ], [ "White", "C. D.", ...
We discuss the calculation of charged Higgs boson production in association with top quark in the MC@NLO framework for combining NLO matrix elements with a parton shower. The process is defined in a model independent manner for wide applicability, and can be used if the charged Higgs boson mass is either greater or less than the mass of the top quark. For the latter mass region, care is needed in defining the charged Higgs production mode due to interference with top pair production. We give a suitable definition applicable in an NLO (plus parton shower) context, and present example results for the LHC.
0904.1743
Matthew Reece
Matthew Reece and Lian-Tao Wang
Searching for the light dark gauge boson in GeV-scale experiments
33 pages, 5 figures; v2: corrected discussion of Upsilon decays, updates to discussion of fixed-target experiments and QED constraints, numerous minor changes, references added; v3: typo corrected relative to the JHEP published version
JHEP 0907:051,2009
10.1088/1126-6708/2009/07/051
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study current constraints and search prospects for a GeV scale vector boson at a range of low energy experiments. It couples to the Standard Model charged particles with a strength <= 10^-3 to 10^-4 of that of the photon. The possibility of such a particle mediating dark matter self-interactions has received much attention recently. We consider searches at low energy high luminosity colliders, meson decays, and fixed target experiments. Based on available data, searches both at colliders and in meson decays can discover or exclude such a scenario if the coupling strength is on the larger side. We emphasize that a dedicated fixed target experiment has a much better potential in searching for such a gauge boson, and outline the desired properties of such an experiment. Two different optimal designs should be implemented to cover the range of coupling strength 10^-3 to 10^-5, and < 10^-5 of the photon, respectively. We also briefly comment on other possible ways of searching for such a gauge boson.
[ { "created": "Mon, 13 Apr 2009 15:58:17 GMT", "version": "v1" }, { "created": "Fri, 8 May 2009 00:08:46 GMT", "version": "v2" }, { "created": "Tue, 23 Feb 2010 02:04:27 GMT", "version": "v3" } ]
2010-02-23
[ [ "Reece", "Matthew", "" ], [ "Wang", "Lian-Tao", "" ] ]
We study current constraints and search prospects for a GeV scale vector boson at a range of low energy experiments. It couples to the Standard Model charged particles with a strength <= 10^-3 to 10^-4 of that of the photon. The possibility of such a particle mediating dark matter self-interactions has received much attention recently. We consider searches at low energy high luminosity colliders, meson decays, and fixed target experiments. Based on available data, searches both at colliders and in meson decays can discover or exclude such a scenario if the coupling strength is on the larger side. We emphasize that a dedicated fixed target experiment has a much better potential in searching for such a gauge boson, and outline the desired properties of such an experiment. Two different optimal designs should be implemented to cover the range of coupling strength 10^-3 to 10^-5, and < 10^-5 of the photon, respectively. We also briefly comment on other possible ways of searching for such a gauge boson.
1105.5472
Jian-Rong Zhang
Jian-Rong Zhang, Ming Zhong, and Ming-Qiu Huang
Could $Z_{b}(10610)$ be a $B^{*}\bar{B}$ molecular state?
6 pages, 3 figures; misprints corrected; the version accepted for publication in Phys. Lett. B
Phys.Lett.B704:312-315,2011
10.1016/j.physletb.2011.09.039
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Assuming the newly observed structure $Z_{b}(10610)$ as a bottomonium-like molecular state $B^{*}\bar{B}$, we calculate its mass in the framework of QCD sum rules. The numerical result is $10.54\pm0.22 GeV$ for $B^{*}\bar{B}$, which coincide with the mass of $Z_{b}(10610)$. This consolidates the statement made by Belle Collaboration that the $Z_{b}(10610)$ resonance could be a $B^{*}\bar{B}$ molecular state.
[ { "created": "Fri, 27 May 2011 03:28:24 GMT", "version": "v1" }, { "created": "Wed, 1 Jun 2011 13:35:13 GMT", "version": "v2" }, { "created": "Tue, 13 Sep 2011 08:29:52 GMT", "version": "v3" } ]
2011-10-11
[ [ "Zhang", "Jian-Rong", "" ], [ "Zhong", "Ming", "" ], [ "Huang", "Ming-Qiu", "" ] ]
Assuming the newly observed structure $Z_{b}(10610)$ as a bottomonium-like molecular state $B^{*}\bar{B}$, we calculate its mass in the framework of QCD sum rules. The numerical result is $10.54\pm0.22 GeV$ for $B^{*}\bar{B}$, which coincide with the mass of $Z_{b}(10610)$. This consolidates the statement made by Belle Collaboration that the $Z_{b}(10610)$ resonance could be a $B^{*}\bar{B}$ molecular state.
0706.1039
Jorge Portoles
V. Mateu and J. Portoles (IFIC, Valencia)
Form Factors in the radiative pion decay
14 pages, no figures. Typos corrected. Accepted for publication in The European Physical Journal C
Eur.Phys.J.C52:325-338,2007
10.1140/epjc/s10052-007-0393-5
IFIC/07-29, FTUV-07-0607
hep-ph hep-ex hep-lat
null
We perform an analysis of the form factors that rule the structure-dependent amplitude in the radiative pion decay. The resonance contributions to pion -> e nu_e gamma decays are computed through the proper construction of the vector and axial-vector form factors by setting the QCD driven asymptotic properties of the three-point Green functions VVP and VAP, and by demanding the smoothing of the form factors at high transfer of momentum. A comparison between theoretical and experimental determinations of the form factors is also carried out. We also consider and evaluate the role played by a non-standard tensor form factor. We conclude that, at present and due to the hadronic incertitudes, the search for New Physics in this process is not feasible.
[ { "created": "Thu, 7 Jun 2007 16:51:41 GMT", "version": "v1" }, { "created": "Tue, 7 Aug 2007 10:15:47 GMT", "version": "v2" } ]
2008-11-26
[ [ "Mateu", "V.", "", "IFIC, Valencia" ], [ "Portoles", "J.", "", "IFIC, Valencia" ] ]
We perform an analysis of the form factors that rule the structure-dependent amplitude in the radiative pion decay. The resonance contributions to pion -> e nu_e gamma decays are computed through the proper construction of the vector and axial-vector form factors by setting the QCD driven asymptotic properties of the three-point Green functions VVP and VAP, and by demanding the smoothing of the form factors at high transfer of momentum. A comparison between theoretical and experimental determinations of the form factors is also carried out. We also consider and evaluate the role played by a non-standard tensor form factor. We conclude that, at present and due to the hadronic incertitudes, the search for New Physics in this process is not feasible.
hep-ph/9701346
Masahiro Kawasaki
M. Kawasaki and T. Yanagida
Constraint on Cosmic Density of the String Moduli Field in Gauge-Mediated Supersymmetry-Breaking Theories
7 pages, a LaTeX2e file and two postscript figures
Phys.Lett. B399 (1997) 45-48
10.1016/S0370-2693(97)00282-7
null
hep-ph
null
We derive a constraint on the cosmic density of string moduli fields in gauge-mediated supersymmetry-breaking theories by requiring that photons emitted from the unstable moduli fields should not exceed the observed X-ray backgrounds. Since mass of the moduli field lies in the range between $O(0.1)$keV and $O(1)$MeV and the decay occurs through a gravitational interaction, the lifetime of the moduli field is much longer than the age of the present universe. The obtained upperbound on their cosmic density becomes more stringent than that from the unclosure condition for the present universe for the mass greater than about 100keV.
[ { "created": "Wed, 22 Jan 1997 10:43:40 GMT", "version": "v1" }, { "created": "Thu, 23 Jan 1997 02:15:05 GMT", "version": "v2" }, { "created": "Sun, 26 Jan 1997 06:05:28 GMT", "version": "v3" } ]
2015-06-25
[ [ "Kawasaki", "M.", "" ], [ "Yanagida", "T.", "" ] ]
We derive a constraint on the cosmic density of string moduli fields in gauge-mediated supersymmetry-breaking theories by requiring that photons emitted from the unstable moduli fields should not exceed the observed X-ray backgrounds. Since mass of the moduli field lies in the range between $O(0.1)$keV and $O(1)$MeV and the decay occurs through a gravitational interaction, the lifetime of the moduli field is much longer than the age of the present universe. The obtained upperbound on their cosmic density becomes more stringent than that from the unclosure condition for the present universe for the mass greater than about 100keV.
hep-ph/0006041
null
H. Davoudiasl, J.L. Hewett, and T.G. Rizzo
Experimental Probes of Localized Gravity: On and Off the Wall
62 pages, Latex, 22 figures
Phys.Rev.D63:075004,2001
10.1103/PhysRevD.63.075004
SLAC-PUB-8436
hep-ph hep-ex hep-th
null
The phenomenology of the Randall-Sundrum model of localized gravity is analyzed in detail for the two scenarios where the Standard Model (SM) gauge and matter fields are either confined to a TeV scale 3-brane or may propagate in a slice of five dimensional anti-deSitter space. In the latter instance, we derive the interactions of the graviton, gauge, and fermion Kaluza-Klein (KK) states. The resulting phenomenological signatures are shown to be highly dependent on the value of the 5-dimensional fermion mass and differ substantially from the case where the SM fields lie on the TeV-brane. In both scenarios, we examine the collider signatures for direct production of the graviton and gauge KK towers as well as their induced contributions to precision electroweak observables. These direct and indirect signatures are found to play a complementary role in the exploration of the model parameter space. In the case where the SM field content resides on the TeV-brane, we show that the LHC can probe the full parameter space and hence will either discover or exclude this model if the scale of electroweak physics on the 3-brane is less than 10 TeV. We also show that spontaneous electroweak symmetry breaking of the SM must take place on the TeV-brane.
[ { "created": "Mon, 5 Jun 2000 00:01:04 GMT", "version": "v1" } ]
2009-07-09
[ [ "Davoudiasl", "H.", "" ], [ "Hewett", "J. L.", "" ], [ "Rizzo", "T. G.", "" ] ]
The phenomenology of the Randall-Sundrum model of localized gravity is analyzed in detail for the two scenarios where the Standard Model (SM) gauge and matter fields are either confined to a TeV scale 3-brane or may propagate in a slice of five dimensional anti-deSitter space. In the latter instance, we derive the interactions of the graviton, gauge, and fermion Kaluza-Klein (KK) states. The resulting phenomenological signatures are shown to be highly dependent on the value of the 5-dimensional fermion mass and differ substantially from the case where the SM fields lie on the TeV-brane. In both scenarios, we examine the collider signatures for direct production of the graviton and gauge KK towers as well as their induced contributions to precision electroweak observables. These direct and indirect signatures are found to play a complementary role in the exploration of the model parameter space. In the case where the SM field content resides on the TeV-brane, we show that the LHC can probe the full parameter space and hence will either discover or exclude this model if the scale of electroweak physics on the 3-brane is less than 10 TeV. We also show that spontaneous electroweak symmetry breaking of the SM must take place on the TeV-brane.
0906.1263
Hans-Werner Hammer
David L. Canham, H.-W. Hammer (Bonn U.), Roxanne P. Springer (Duke U.)
On the scattering of D and D* mesons off the X(3872)
12 pages, 5 figures, revtex4
Phys.Rev.D80:014009,2009
10.1103/PhysRevD.80.014009
HISKP-TH-09/15
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Both the mass (just below the D^{*0}Dbar^0 threshold) and the likely quantum numbers (J^{PC}=1^{++}) of the X(3872) suggest that it is either a weakly-bound hadronic ``molecule'' or a virtual state of charmed mesons. Assuming the X(3872) is a weakly-bound molecule, the scattering of neutral D and D* mesons off the X(3872) can be predicted from the X(3872) binding energy. We calculate the phase shifts and cross section for scattering of D^0 and D^{*0} mesons and their antiparticles off the X(3872) in an effective field theory for short-range interactions. This provides another example of a three-body process, along with those in nuclear and atomic systems, that displays universal properties. It may be possible to extract the scattering within the final state interactions of B_c decays and/or other LHC events.
[ { "created": "Sat, 6 Jun 2009 10:40:30 GMT", "version": "v1" } ]
2009-09-02
[ [ "Canham", "David L.", "", "Bonn U." ], [ "Hammer", "H. -W.", "", "Bonn U." ], [ "Springer", "Roxanne P.", "", "Duke U." ] ]
Both the mass (just below the D^{*0}Dbar^0 threshold) and the likely quantum numbers (J^{PC}=1^{++}) of the X(3872) suggest that it is either a weakly-bound hadronic ``molecule'' or a virtual state of charmed mesons. Assuming the X(3872) is a weakly-bound molecule, the scattering of neutral D and D* mesons off the X(3872) can be predicted from the X(3872) binding energy. We calculate the phase shifts and cross section for scattering of D^0 and D^{*0} mesons and their antiparticles off the X(3872) in an effective field theory for short-range interactions. This provides another example of a three-body process, along with those in nuclear and atomic systems, that displays universal properties. It may be possible to extract the scattering within the final state interactions of B_c decays and/or other LHC events.
hep-ph/9605332
Mark Hindmarsh
Mark Hindmarsh (Sussex University)
Analytic scaling solutions for cosmic domain walls
7pp Plain LaTeX
Phys. Rev. Lett. 77, 4495 (1996)
10.1103/PhysRevLett.77.4495
SUSX-TH-96-005
hep-ph astro-ph cond-mat
null
A relativistic generalisation of a well-known method for approximating the dynamics of topological defects in condensed matter is constructed, and applied to the evolution of domain walls in a cosmological context. It is shown that there are self-similar ``scaling'' solutions, for which one can in principle calculate many quantities of interest without recourse to numerical simulations. Here, the area density in the scaling regime is calculated in various backgrounds. Remarkably good agreement with numerical simulations is obtained.
[ { "created": "Thu, 16 May 1996 15:20:19 GMT", "version": "v1" } ]
2016-08-24
[ [ "Hindmarsh", "Mark", "", "Sussex University" ] ]
A relativistic generalisation of a well-known method for approximating the dynamics of topological defects in condensed matter is constructed, and applied to the evolution of domain walls in a cosmological context. It is shown that there are self-similar ``scaling'' solutions, for which one can in principle calculate many quantities of interest without recourse to numerical simulations. Here, the area density in the scaling regime is calculated in various backgrounds. Remarkably good agreement with numerical simulations is obtained.
1603.02974
Danny van Dyk
Stefan Meinel, Danny van Dyk
Using $\Lambda_b\to \Lambda\mu^+\mu^-$ data within a Bayesian analysis of $|\Delta B| = |\Delta S| = 1$ decays
9 pages, 2 figures; v2 as published: added some clarifications, changed setup for model comparisons, expanded conclusions
Phys. Rev. D 94, 013007 (2016)
10.1103/PhysRevD.94.013007
EOS-2016-02, RBRC-1168, ZU-TH-7/16
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the impact of including the baryonic decay $\Lambda_b\to \Lambda(\to p \pi^-)\mu^+\mu^-$ in a Bayesian analysis of $|\Delta B | = |\Delta S| = 1$ transitions. We perform fits of the Wilson coefficients $C_{9}$, $C_{9'}$, $C_{10}$ and $C_{10'}$, in addition to the relevant nuisance parameters. Our analysis combines data for the differential branching fraction and three angular observables of $\Lambda_b\to \Lambda(\to p \pi^-)\mu^+\mu^-$ with data for the branching ratios of $B_s \to \mu^+\mu^-$ and inclusive $b \to s\ell^+\ell^-$ decays. Newly available precise lattice QCD results for the full set of $\Lambda_b \to \Lambda$ form factors are used to evaluate the observables of the baryonic decay. Our fits prefer shifts to $C_{9}$ that are opposite in sign compared to those found in global fits of only mesonic decays, and the posterior odds show no evidence of physics beyond the Standard Model. We investigate a possible hadronic origin of the observed tensions between theory and experiment.
[ { "created": "Wed, 9 Mar 2016 17:36:42 GMT", "version": "v1" }, { "created": "Tue, 2 Aug 2016 12:03:23 GMT", "version": "v2" } ]
2016-08-03
[ [ "Meinel", "Stefan", "" ], [ "van Dyk", "Danny", "" ] ]
We study the impact of including the baryonic decay $\Lambda_b\to \Lambda(\to p \pi^-)\mu^+\mu^-$ in a Bayesian analysis of $|\Delta B | = |\Delta S| = 1$ transitions. We perform fits of the Wilson coefficients $C_{9}$, $C_{9'}$, $C_{10}$ and $C_{10'}$, in addition to the relevant nuisance parameters. Our analysis combines data for the differential branching fraction and three angular observables of $\Lambda_b\to \Lambda(\to p \pi^-)\mu^+\mu^-$ with data for the branching ratios of $B_s \to \mu^+\mu^-$ and inclusive $b \to s\ell^+\ell^-$ decays. Newly available precise lattice QCD results for the full set of $\Lambda_b \to \Lambda$ form factors are used to evaluate the observables of the baryonic decay. Our fits prefer shifts to $C_{9}$ that are opposite in sign compared to those found in global fits of only mesonic decays, and the posterior odds show no evidence of physics beyond the Standard Model. We investigate a possible hadronic origin of the observed tensions between theory and experiment.
hep-ph/0306238
Daniele Fargion
D. Fargion
Ultra High Energy Cosmic Rays, Z-Shower and Neutrino Astronomy by Horizontal-Upward Tau Air-Showers
24 pages, 19 figures, Invited talk at the X International Workshop on Neutrino Telescopes, Venice, Italy, March 11-14, 2003
Xth Neutrino Telescope Conference-Venice,Ed. by Milla Baldo Ceolin, 11-14 March 2003,Ed.Papergraf.,Vol-II, 433-455,2003.
null
null
hep-ph astro-ph gr-qc
null
Ultra High Cosmic Rays (UHECR) Astronomy may be correlated to a primary parental Neutrino Astronomy: indeed any far BL Lac Jet or GRB, sources of UHECR, located at cosmic edges, may send its signal, overcoming the severe GZK cut-off, by help of UHE ZeV energetic neutrino primary. These UHE neutrino scattering on relic light ones (spread on wide Hot Local Groups Halos) maybe fine-tuned : E_(nu) =(M_Z)^2/m_(nu) = 4 10^(22) eV *((0.1eV)/m_(nu)), to combine at once the observed light neutrino masses and the UHECR spectra, leading to a relativistic Z-Shower in Hot Dark Halos (e few tens Mpc wide) whose final nuclear component traces the UHECR event on Earth. Therefore UHECR (with no longer volme GZK constrains) may point to far BL Lac sources. This Z-Burst (Z-Shower) model calls for large neutrino fluxes. Even if Nature do not follow the present Z-model, UHECR while being cut-off by Big Bang Radiation, must produce a minimal UHE neutrino flux, the GZK neutrino secondaries. For both reasons such UHE Neutrino Astronomy must be tested on Earth. Lowest High Energy Astronomy is searched by AMANDA, ANTARES underground deterctors by muons tracks. We suggest a complementary higher energy Neutrino Tau Astronomy inducing Horizontal and Upward Tau AirShowers. Possible early evidence of such a New Neutrino UPTAUs (Upward Tau Showers at PeVs energies) Astronomy may be in BATSE records of Upward Terrestrial Gamma Flashes. Future signals must be found in detectors as EUSO, seeking Upward-Horizontal events: indeed even minimal, guaranteed, GZK neutrino fluxes may be better observed if EUSO threshold reaches 10^(19) eV by enlarging its telescope size.
[ { "created": "Tue, 24 Jun 2003 18:15:18 GMT", "version": "v1" } ]
2007-05-23
[ [ "Fargion", "D.", "" ] ]
Ultra High Cosmic Rays (UHECR) Astronomy may be correlated to a primary parental Neutrino Astronomy: indeed any far BL Lac Jet or GRB, sources of UHECR, located at cosmic edges, may send its signal, overcoming the severe GZK cut-off, by help of UHE ZeV energetic neutrino primary. These UHE neutrino scattering on relic light ones (spread on wide Hot Local Groups Halos) maybe fine-tuned : E_(nu) =(M_Z)^2/m_(nu) = 4 10^(22) eV *((0.1eV)/m_(nu)), to combine at once the observed light neutrino masses and the UHECR spectra, leading to a relativistic Z-Shower in Hot Dark Halos (e few tens Mpc wide) whose final nuclear component traces the UHECR event on Earth. Therefore UHECR (with no longer volme GZK constrains) may point to far BL Lac sources. This Z-Burst (Z-Shower) model calls for large neutrino fluxes. Even if Nature do not follow the present Z-model, UHECR while being cut-off by Big Bang Radiation, must produce a minimal UHE neutrino flux, the GZK neutrino secondaries. For both reasons such UHE Neutrino Astronomy must be tested on Earth. Lowest High Energy Astronomy is searched by AMANDA, ANTARES underground deterctors by muons tracks. We suggest a complementary higher energy Neutrino Tau Astronomy inducing Horizontal and Upward Tau AirShowers. Possible early evidence of such a New Neutrino UPTAUs (Upward Tau Showers at PeVs energies) Astronomy may be in BATSE records of Upward Terrestrial Gamma Flashes. Future signals must be found in detectors as EUSO, seeking Upward-Horizontal events: indeed even minimal, guaranteed, GZK neutrino fluxes may be better observed if EUSO threshold reaches 10^(19) eV by enlarging its telescope size.
0912.0743
Matteo Bertolini
Riccardo Argurio, Matteo Bertolini, Gabriele Ferretti, Alberto Mariotti
Patterns of Soft Masses from General Semi-Direct Gauge Mediation
26 pages, 5 figures; v2: refs added; v3: minor corrections, clarifications added, mainly in section 4
JHEP 1003:008,2010
10.1007/JHEP03(2010)008
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We give a general formulation of semi-direct gauge mediation of supersymmetry breaking where the messengers interact with the hidden sector only through a weakly gauged group. Using this general formulation, we provide an explicit proof that the MSSM gaugino masses are vanishing to leading order in the gauge couplings. On the other hand, the MSSM sfermion masses have, generically, a non-vanishing leading contribution. We discuss how such a mechanism can successfully be combined with other mediation schemes which give tachyonic sfermions, such as sequestered anomaly mediation and some direct gauge mediation models.
[ { "created": "Fri, 4 Dec 2009 08:18:10 GMT", "version": "v1" }, { "created": "Mon, 14 Dec 2009 11:18:59 GMT", "version": "v2" }, { "created": "Mon, 22 Feb 2010 15:25:40 GMT", "version": "v3" } ]
2014-11-20
[ [ "Argurio", "Riccardo", "" ], [ "Bertolini", "Matteo", "" ], [ "Ferretti", "Gabriele", "" ], [ "Mariotti", "Alberto", "" ] ]
We give a general formulation of semi-direct gauge mediation of supersymmetry breaking where the messengers interact with the hidden sector only through a weakly gauged group. Using this general formulation, we provide an explicit proof that the MSSM gaugino masses are vanishing to leading order in the gauge couplings. On the other hand, the MSSM sfermion masses have, generically, a non-vanishing leading contribution. We discuss how such a mechanism can successfully be combined with other mediation schemes which give tachyonic sfermions, such as sequestered anomaly mediation and some direct gauge mediation models.
hep-ph/9504318
Shigetaka Moriyama
Shigetaka Moriyama (Department of Physics, School of Science, University of Tokyo)
A proposal to search for a monochromatic component of solar axions using $^{57}$Fe
9 pages, REVTeX, 2 PostScript figures
Phys.Rev.Lett.75:3222-3225,1995
10.1103/PhysRevLett.75.3222
null
hep-ph hep-ex
null
A new experimental scheme is proposed to search for almost monochromatic solar axions, whose existence has not been discussed heretofore. The axions would be produced when thermally excited $^{57}$Fe in the sun relaxes to its ground state and could be detected via resonant excitation of the same nuclide in a laboratory. A detailed calculation shows that the rate of the excitation is up to order 10 events/day/kg-$^{57}$Fe. The excitation can be detected efficiently using bolometers or liquid scintillators.
[ { "created": "Tue, 18 Apr 1995 03:46:40 GMT", "version": "v1" } ]
2008-11-26
[ [ "Moriyama", "Shigetaka", "", "Department of Physics, School of Science,\n University of Tokyo" ] ]
A new experimental scheme is proposed to search for almost monochromatic solar axions, whose existence has not been discussed heretofore. The axions would be produced when thermally excited $^{57}$Fe in the sun relaxes to its ground state and could be detected via resonant excitation of the same nuclide in a laboratory. A detailed calculation shows that the rate of the excitation is up to order 10 events/day/kg-$^{57}$Fe. The excitation can be detected efficiently using bolometers or liquid scintillators.
1409.1463
Maxim Dvornikov
Maxim Dvornikov (University of S\~ao Paulo, IZMIRAN)
Generation of cosmic magnetic fields in electroweak plasma
3 pages, 7 pdf figures, pdflatex, Elsevier style; Contribution to the Proceedings of 37th ICHEP
Nucl.Part.Phys.Proc. 273-275 (2015) 2342-2344
10.1016/j.nuclphysbps.2015.09.385
null
hep-ph astro-ph.CO astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the generation of strong magnetic fields in magnetars and in the early universe. For this purpose we calculate the antisymmetric contribution to the photon polarization tensor in a medium consisting of an electron-positron plasma and a gas of neutrinos and antineutrinos, interacting within the Standard Model. Such a contribution exactly takes into account the temperature and the chemical potential of plasma as well as the photon dispersion law in this background matter. It is shown that a nonvanishing Chern-Simons parameter, which appears if there is a nonzero asymmetry between neutrinos and antineutrinos, leads to the instability of a magnetic field resulting to its growth. We apply our result to the description of the magnetic field amplification in the first second of a supernova explosion. It is suggested that this mechanism can explain strong magnetic fields of magnetars. Then we use our approach to study the cosmological magnetic field evolution. We find a lower bound on the neutrino asymmetries consistent with the well-known Big Bang nucleosynthesis bound in a hot universe plasma. Finally we examine the issue of whether a magnetic field can be amplified in a background matter consisting of self-interacting electrons and positrons.
[ { "created": "Thu, 4 Sep 2014 15:15:57 GMT", "version": "v1" } ]
2016-08-10
[ [ "Dvornikov", "Maxim", "", "University of São Paulo, IZMIRAN" ] ]
We study the generation of strong magnetic fields in magnetars and in the early universe. For this purpose we calculate the antisymmetric contribution to the photon polarization tensor in a medium consisting of an electron-positron plasma and a gas of neutrinos and antineutrinos, interacting within the Standard Model. Such a contribution exactly takes into account the temperature and the chemical potential of plasma as well as the photon dispersion law in this background matter. It is shown that a nonvanishing Chern-Simons parameter, which appears if there is a nonzero asymmetry between neutrinos and antineutrinos, leads to the instability of a magnetic field resulting to its growth. We apply our result to the description of the magnetic field amplification in the first second of a supernova explosion. It is suggested that this mechanism can explain strong magnetic fields of magnetars. Then we use our approach to study the cosmological magnetic field evolution. We find a lower bound on the neutrino asymmetries consistent with the well-known Big Bang nucleosynthesis bound in a hot universe plasma. Finally we examine the issue of whether a magnetic field can be amplified in a background matter consisting of self-interacting electrons and positrons.
1102.1868
Kokoulina Elena Sergeevna
E.A. Kuraev, V.V. Bytev and E.S. Kokoulina
Azimuthal correlation of gluon jets created in proton-antiproton annihilation
7 pages, 4 figures
Nucl.Phys.B851:551-564,2011
10.1016/j.nuclphysb.2011.06.008
null
hep-ph nucl-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Annihilation process of proton and antiproton to guark antiquark pair accompanied by emission of two additional gluon jets with intermediate state of vector meson is considered.Strong azimuthal correlation is revealed of two gluonic jets,effectively created in the same plane.Some applications to cosmic ray events and to LHC experiments are discussed.
[ { "created": "Wed, 9 Feb 2011 14:15:19 GMT", "version": "v1" } ]
2011-08-11
[ [ "Kuraev", "E. A.", "" ], [ "Bytev", "V. V.", "" ], [ "Kokoulina", "E. S.", "" ] ]
Annihilation process of proton and antiproton to guark antiquark pair accompanied by emission of two additional gluon jets with intermediate state of vector meson is considered.Strong azimuthal correlation is revealed of two gluonic jets,effectively created in the same plane.Some applications to cosmic ray events and to LHC experiments are discussed.
1501.00459
Josef Pradler
Anthony Fradette, Maxim Pospelov, Josef Pradler, Adam Ritz
Nucleosynthesis constraints on the faint vector portal
6 pages, 4 figures, contribution to the Dark Matter, Hadron Physics and Fusion Physics (DHF2014) conference, Messina, Italy, Sept. 24-26, 2014
null
null
null
hep-ph astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
New Abelian U(1)' gauge bosons $V_{\mu}$ can couple to the Standard Model through mixing of the associated field strength tensor $V_{\mu\nu}$ with the one from hypercharge, $F_{\mu\nu}^Y$. Here we consider early Universe sensitivity to this vector portal and show that the effective mixing parameter with the photon, $\kappa$, is being probed for vector masses in the GeV ballpark down to values $10^{-10} \lesssim \kappa \lesssim 10^{-14}$ where no terrestrial probes exist. The ensuing constraints are based on a detailed calculation of the vector relic abundance and an in-depth analysis of relevant nucleosynthesis processes.
[ { "created": "Fri, 2 Jan 2015 19:13:02 GMT", "version": "v1" } ]
2015-01-05
[ [ "Fradette", "Anthony", "" ], [ "Pospelov", "Maxim", "" ], [ "Pradler", "Josef", "" ], [ "Ritz", "Adam", "" ] ]
New Abelian U(1)' gauge bosons $V_{\mu}$ can couple to the Standard Model through mixing of the associated field strength tensor $V_{\mu\nu}$ with the one from hypercharge, $F_{\mu\nu}^Y$. Here we consider early Universe sensitivity to this vector portal and show that the effective mixing parameter with the photon, $\kappa$, is being probed for vector masses in the GeV ballpark down to values $10^{-10} \lesssim \kappa \lesssim 10^{-14}$ where no terrestrial probes exist. The ensuing constraints are based on a detailed calculation of the vector relic abundance and an in-depth analysis of relevant nucleosynthesis processes.
2006.08616
Peihong Gu
Pei-Hong Gu
Weinberg dimension-5 operator by vector-like lepton doublets
5 pages, 6 figures
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It is well known that a Weinberg dimension-5 operator for small neutrino masses can be realized at tree level in three types of renormalizable models: (i) the type-I seesaw mediated by fermion singlets, (ii) the type-II seesaw mediated by Higgs triplets, (iii) the type-III seesaw mediated by fermion triplets. We here point out such operator can be also induced at tree level by vector-like lepton doublets in association with unusual fermion singlets, Higgs triplets or fermion triplets. If these unusual fermion singlets, Higgs triplets or fermion triplets are heavy enough, their decays can generate a lepton asymmetry to explain the cosmic baryon asymmetry, meanwhile, the vector-like lepton doublets can lead to a novel inverse or linear seesaw with rich observable phenomena. We further specify our scenario can be naturally embedded into a grand unification theory without the conventional type-I, type-II or type-III seesaw.
[ { "created": "Mon, 15 Jun 2020 17:01:58 GMT", "version": "v1" } ]
2020-06-17
[ [ "Gu", "Pei-Hong", "" ] ]
It is well known that a Weinberg dimension-5 operator for small neutrino masses can be realized at tree level in three types of renormalizable models: (i) the type-I seesaw mediated by fermion singlets, (ii) the type-II seesaw mediated by Higgs triplets, (iii) the type-III seesaw mediated by fermion triplets. We here point out such operator can be also induced at tree level by vector-like lepton doublets in association with unusual fermion singlets, Higgs triplets or fermion triplets. If these unusual fermion singlets, Higgs triplets or fermion triplets are heavy enough, their decays can generate a lepton asymmetry to explain the cosmic baryon asymmetry, meanwhile, the vector-like lepton doublets can lead to a novel inverse or linear seesaw with rich observable phenomena. We further specify our scenario can be naturally embedded into a grand unification theory without the conventional type-I, type-II or type-III seesaw.
1907.07188
Seodong Shin
Radovan Dermisek, Enrico Lunghi, Seodong Shin
Cascade decays of Heavy Higgs bosons through vectorlike quarks
21 pages, 9 figures
JHEP03, 029 (2020)
10.1007/JHEP03(2020)029
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study cascade decays of heavy neutral Higgs bosons through vectorlike quarks. We focus on scenarios where decay modes into pairs of vectorlike quarks are not kinematically open which extends the sensitivity of the LHC to larger masses. Assuming only mixing with the third family of standard model quarks the new decay modes of heavy Higgs bosons are: $H\to t_4 t \to Wbt, Zt t, ht t$ and $H\to b_4 b \to Wtb, Zb b, hb b$, where $t_4$ ($b_4$) is the new up-type (down-type) quark mass eigenstate. In the numerical analysis we assume the CP even Higgs boson in the two Higgs doublet model type-II but the signatures are relevant for many other scenarios. We identify the region of the parameter space where these decay modes are significant or can even dominate, and thus they provide the best opportunities for the simultaneous discovery of a new Higgs boson and vectorlike quarks. We further explore the reach of the High Luminosity LHC for two representative decay modes, $t_4\to Zt\to\ell\ell t$ and $b_4\to Zb\to\ell\ell b$, and found that cross sections at a 0.1 fb level can be probed with simple cut based analyses. We also find that the rates for Higgs cascade decays can be much larger than the rates for a single production of vectorlike quarks. Furthermore, the reach for vectorlike quarks in Higgs cascade decays and pair production extends to comparable masses.
[ { "created": "Tue, 16 Jul 2019 18:00:00 GMT", "version": "v1" }, { "created": "Sun, 8 Mar 2020 14:46:35 GMT", "version": "v2" } ]
2020-03-10
[ [ "Dermisek", "Radovan", "" ], [ "Lunghi", "Enrico", "" ], [ "Shin", "Seodong", "" ] ]
We study cascade decays of heavy neutral Higgs bosons through vectorlike quarks. We focus on scenarios where decay modes into pairs of vectorlike quarks are not kinematically open which extends the sensitivity of the LHC to larger masses. Assuming only mixing with the third family of standard model quarks the new decay modes of heavy Higgs bosons are: $H\to t_4 t \to Wbt, Zt t, ht t$ and $H\to b_4 b \to Wtb, Zb b, hb b$, where $t_4$ ($b_4$) is the new up-type (down-type) quark mass eigenstate. In the numerical analysis we assume the CP even Higgs boson in the two Higgs doublet model type-II but the signatures are relevant for many other scenarios. We identify the region of the parameter space where these decay modes are significant or can even dominate, and thus they provide the best opportunities for the simultaneous discovery of a new Higgs boson and vectorlike quarks. We further explore the reach of the High Luminosity LHC for two representative decay modes, $t_4\to Zt\to\ell\ell t$ and $b_4\to Zb\to\ell\ell b$, and found that cross sections at a 0.1 fb level can be probed with simple cut based analyses. We also find that the rates for Higgs cascade decays can be much larger than the rates for a single production of vectorlike quarks. Furthermore, the reach for vectorlike quarks in Higgs cascade decays and pair production extends to comparable masses.
hep-ph/0409291
Francisco Larios
F. Larios, F. Penunuri, M.A. Perez
Top-pions and single top production at HERA and THERA
5 pages, 2 figures. Paragraph and 1 reference added
Phys.Lett. B605 (2005) 301-305
10.1016/j.physletb.2004.11.053
null
hep-ph
null
We study single top quark production at the HERA and THERA colliders as coming from the FCNC vertices tcgamma and tcZ that appear at one loop level in Topcolor-assisted technicolor models (TC2). In contrast with previous expectations, we find that the production cross section is of order 10^-6 pb for HERA and 10^-4 pb for THERA (even lower that the SM prediction). Therefore, none of the two colliders are capable to probe the pseudoscalar top-pion or the scalar top-higgs predicted in TC2 models via single top production.
[ { "created": "Fri, 24 Sep 2004 20:26:10 GMT", "version": "v1" }, { "created": "Fri, 19 Nov 2004 20:58:54 GMT", "version": "v2" } ]
2010-04-05
[ [ "Larios", "F.", "" ], [ "Penunuri", "F.", "" ], [ "Perez", "M. A.", "" ] ]
We study single top quark production at the HERA and THERA colliders as coming from the FCNC vertices tcgamma and tcZ that appear at one loop level in Topcolor-assisted technicolor models (TC2). In contrast with previous expectations, we find that the production cross section is of order 10^-6 pb for HERA and 10^-4 pb for THERA (even lower that the SM prediction). Therefore, none of the two colliders are capable to probe the pseudoscalar top-pion or the scalar top-higgs predicted in TC2 models via single top production.
hep-ph/9904503
Gabor Papp
Gabor Papp, George Fai and Peter Levai
Hard Photons and Neutral Pions from RHIC
5 pages with 4 eps figures included. Proceeding of the APS Atlanta meeting
null
null
null
hep-ph nucl-th
null
In order to fix the parameters for predictions of hard photon and pion production in $Au+Au$ collisions at $\sqrt{s}=200$ GeV, proton-proton and proton-nucleus data are analyzed in perturbative QCD in the energy range $\sqrt{s} \approx 20-60$ GeV and a prediction at RHIC energy is given.
[ { "created": "Fri, 30 Apr 1999 15:06:12 GMT", "version": "v1" } ]
2007-05-23
[ [ "Papp", "Gabor", "" ], [ "Fai", "George", "" ], [ "Levai", "Peter", "" ] ]
In order to fix the parameters for predictions of hard photon and pion production in $Au+Au$ collisions at $\sqrt{s}=200$ GeV, proton-proton and proton-nucleus data are analyzed in perturbative QCD in the energy range $\sqrt{s} \approx 20-60$ GeV and a prediction at RHIC energy is given.
hep-ph/0507117
Jiaolin Xu
Jiao Lin Xu
Deducing Quark Rest Masses with Phenomenological Formulae
19 pages, 1 figure
null
null
null
hep-ph
null
Using phenomenological formulae, we can deduce the rest masses and intrinsic quantum numbers (I, S, C, B and Q) of quarks, baryons and mesons from only one unflavored elementary quark family. The deduced quantum numbers match experimental results exactly, and the deduced rest masses are 98.5% (or 97%) consistent with experimental results for baryons (or mesons). This paper predicts some quarks [d_{S}(773), d_{S}(1933) and u_{C}(6073)], baryons [$\Lambda_{c}(6599)$, $\Lambda_{b)(9959)$] and mesons [D(6231), B(9502)]. PACS: 12.39.-x; 14.65.-q; 14.20.-c. Keywords: phenomenological, beyond the standard model.
[ { "created": "Mon, 11 Jul 2005 18:23:40 GMT", "version": "v1" }, { "created": "Wed, 3 Aug 2005 19:12:09 GMT", "version": "v2" } ]
2007-05-23
[ [ "Xu", "Jiao Lin", "" ] ]
Using phenomenological formulae, we can deduce the rest masses and intrinsic quantum numbers (I, S, C, B and Q) of quarks, baryons and mesons from only one unflavored elementary quark family. The deduced quantum numbers match experimental results exactly, and the deduced rest masses are 98.5% (or 97%) consistent with experimental results for baryons (or mesons). This paper predicts some quarks [d_{S}(773), d_{S}(1933) and u_{C}(6073)], baryons [$\Lambda_{c}(6599)$, $\Lambda_{b)(9959)$] and mesons [D(6231), B(9502)]. PACS: 12.39.-x; 14.65.-q; 14.20.-c. Keywords: phenomenological, beyond the standard model.
1711.05999
Dipanwita Dutta
Dipanwita Dutta, Ruchi Chudasama
Photoproduction of Upsilon in Ultraperipheral Collisions at LHC Run2 energies
7 pages, 7 figures
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The exclusive $\Upsilon$ photoproduction in ultraperipheral proton-nucleus and nucleus-nucleus collisions at LHC energies is being investigated using pQCD framework which constrain the gluon distribution in the proton and nuclei at low $x$. Rapidity distributions of $\Upsilon$ photoproduction with different gluon distribution parameterization and gluon shadowing for nuclear PDFs including photon flux suppression for strong interaction, are being presented at LHC energies. Predictions done for ultraperipheral collisions at $\sqrt s$=$8.16$ TeV in pPb, and at $\sqrt s$=$5.02$ TeV in PbPb collisions which are LHC Run 2 Heavy Ion collision scenario and measurements of cross-section will be available soon.
[ { "created": "Thu, 16 Nov 2017 09:26:57 GMT", "version": "v1" } ]
2017-11-17
[ [ "Dutta", "Dipanwita", "" ], [ "Chudasama", "Ruchi", "" ] ]
The exclusive $\Upsilon$ photoproduction in ultraperipheral proton-nucleus and nucleus-nucleus collisions at LHC energies is being investigated using pQCD framework which constrain the gluon distribution in the proton and nuclei at low $x$. Rapidity distributions of $\Upsilon$ photoproduction with different gluon distribution parameterization and gluon shadowing for nuclear PDFs including photon flux suppression for strong interaction, are being presented at LHC energies. Predictions done for ultraperipheral collisions at $\sqrt s$=$8.16$ TeV in pPb, and at $\sqrt s$=$5.02$ TeV in PbPb collisions which are LHC Run 2 Heavy Ion collision scenario and measurements of cross-section will be available soon.
1712.02550
Qiang Zhao
Wen Qin, Qiang Zhao, and Xian-Hui Zhong
Revisiting the pseudoscalar meson and glueball mixing and key issues in the search for pseudscalar glueball state
17 pages, 5 figures; Revised version accepted by Phys. Rev. D
Phys. Rev. D 97, 096002 (2018)
10.1103/PhysRevD.97.096002
null
hep-ph hep-ex nucl-ex nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We revisit the mixing mechanism for pesudscalar mesons and glueball which is introduced by the axial vector anomaly. We demonstrate that the physical mass of the pseudoscalar glueball does not favor to be lower than 1.8 GeV if all the parameters are reasonably constrained. This conclusion, on the one hand, can accommodate the pseudoscalar glueball mass calculated by Lattice QCD, and on the other hand, is consistent with the high-statistics analyses at BESIII that all the available measurements do not support the presence of two closely overlapping pseudoscalar states in any exclusive channel. Such a result is in agreement with the recent claim that the slightly shifted peak positions for two possible states $\eta(1405)$ and $\eta(1475)$ observed in different channels are actually originated from one single state with the triangle singularity interferences. By resolving this long-standing paradox, one should pay more attention to higher mass region for the purpose of searching for the pseudoscalar glueball candidate.
[ { "created": "Thu, 7 Dec 2017 09:38:06 GMT", "version": "v1" }, { "created": "Wed, 4 Apr 2018 17:06:51 GMT", "version": "v2" } ]
2018-05-09
[ [ "Qin", "Wen", "" ], [ "Zhao", "Qiang", "" ], [ "Zhong", "Xian-Hui", "" ] ]
We revisit the mixing mechanism for pesudscalar mesons and glueball which is introduced by the axial vector anomaly. We demonstrate that the physical mass of the pseudoscalar glueball does not favor to be lower than 1.8 GeV if all the parameters are reasonably constrained. This conclusion, on the one hand, can accommodate the pseudoscalar glueball mass calculated by Lattice QCD, and on the other hand, is consistent with the high-statistics analyses at BESIII that all the available measurements do not support the presence of two closely overlapping pseudoscalar states in any exclusive channel. Such a result is in agreement with the recent claim that the slightly shifted peak positions for two possible states $\eta(1405)$ and $\eta(1475)$ observed in different channels are actually originated from one single state with the triangle singularity interferences. By resolving this long-standing paradox, one should pay more attention to higher mass region for the purpose of searching for the pseudoscalar glueball candidate.
hep-ph/9912497
Jusak Tandean
Jusak Tandean
New Physics and Short-Distance s->d gamma Transition in Omega^- -> Cascade^- gamma Decay
9 pages, latex, few minor changes and additions, to appear in Phys. Rev. D
Phys.Rev. D61 (2000) 114022
10.1103/PhysRevD.61.114022
ISU-HET-99-15
hep-ph hep-ex
null
We study the contributions of physics beyond the standard model to the short-distance s->d gamma transition in Omega^- -> Cascade^- gamma decay. We explore the possibility that the new interactions remove the chirality suppression which occurs in the standard-model contribution to s->d gamma and enhance the effect of this coupling by factors of a heavy-mass scale relative to the s-quark mass. We consider two of the popular models for new physics, and, after taking into account constraints from other processes, find that their contributions can be larger than that of the standard model by up to a few times, which suggests that the yet unobserved Omega^- -> Cascade^- gamma decay is a likely probe for new physics.
[ { "created": "Thu, 23 Dec 1999 23:56:08 GMT", "version": "v1" }, { "created": "Mon, 20 Mar 2000 18:49:56 GMT", "version": "v2" } ]
2009-10-31
[ [ "Tandean", "Jusak", "" ] ]
We study the contributions of physics beyond the standard model to the short-distance s->d gamma transition in Omega^- -> Cascade^- gamma decay. We explore the possibility that the new interactions remove the chirality suppression which occurs in the standard-model contribution to s->d gamma and enhance the effect of this coupling by factors of a heavy-mass scale relative to the s-quark mass. We consider two of the popular models for new physics, and, after taking into account constraints from other processes, find that their contributions can be larger than that of the standard model by up to a few times, which suggests that the yet unobserved Omega^- -> Cascade^- gamma decay is a likely probe for new physics.
1510.01715
Taushif Ahmed
Taushif Ahmed, Thomas Gehrmann, Prakash Mathews, Narayan Rana and V. Ravindran
Pseudo-scalar Form Factors at Three Loops in QCD
39 pages, version to appear in JHEP, minor typos corrected, a comment regarding LI and IBP identities is added in Sec. 3.1, reference updated
null
10.1007/JHEP11(2015)169
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The coupling of a pseudo-scalar Higgs boson to gluons is mediated through a heavy quark loop. In the limit of large quark mass, it is described by an effective Lagrangian that only admits light degrees of freedom. In this effective theory, we compute the three-loop massless QCD corrections to the form factor that describes the coupling of a pseudo-scalar Higgs boson to gluons. Due to the axial anomaly, the pseudo-scalar operator for the gluonic field strength mixes with the divergence of the axial vector current. Working in dimensional regularization and using the 't~Hooft-Veltman prescription for the axial vector current, we compute the three-loop pseudo-scalar form factors for massless quarks and gluons. Using the universal infrared factorization properties, we independently derive the three-loop operator mixing and finite operator renormalisation from the renormalisation group equation for the form factors, thereby confirming recent results in the operator product expansion. The finite part of the three-loop form factor is an important ingredient to the precise prediction of the pseudo-scalar Higgs boson production cross section at hadron colliders. We discuss potential applications and derive the hard matching coefficient in soft-collinear effective theory.
[ { "created": "Tue, 6 Oct 2015 19:33:57 GMT", "version": "v1" }, { "created": "Tue, 24 Nov 2015 14:17:59 GMT", "version": "v2" } ]
2016-01-20
[ [ "Ahmed", "Taushif", "" ], [ "Gehrmann", "Thomas", "" ], [ "Mathews", "Prakash", "" ], [ "Rana", "Narayan", "" ], [ "Ravindran", "V.", "" ] ]
The coupling of a pseudo-scalar Higgs boson to gluons is mediated through a heavy quark loop. In the limit of large quark mass, it is described by an effective Lagrangian that only admits light degrees of freedom. In this effective theory, we compute the three-loop massless QCD corrections to the form factor that describes the coupling of a pseudo-scalar Higgs boson to gluons. Due to the axial anomaly, the pseudo-scalar operator for the gluonic field strength mixes with the divergence of the axial vector current. Working in dimensional regularization and using the 't~Hooft-Veltman prescription for the axial vector current, we compute the three-loop pseudo-scalar form factors for massless quarks and gluons. Using the universal infrared factorization properties, we independently derive the three-loop operator mixing and finite operator renormalisation from the renormalisation group equation for the form factors, thereby confirming recent results in the operator product expansion. The finite part of the three-loop form factor is an important ingredient to the precise prediction of the pseudo-scalar Higgs boson production cross section at hadron colliders. We discuss potential applications and derive the hard matching coefficient in soft-collinear effective theory.
1408.5463
Timothy Hobbs
T. J. Hobbs
The Nonperturbative Structure of Hadrons
PhD dissertation, Indiana University --- 232 pages; to be separately published by ProQuest/UMI
null
null
null
hep-ph hep-th nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this thesis we explore a diverse array of issues that strike at the inherently nonperturbative structure of hadrons at momenta below the QCD confinement scale. In so doing, we mainly seek a better control over the partonic substructure of strongly-interacting matter, especially as this relates to the nonperturbative effects that both motivate and complicate experiments --- particularly DIS; among others, such considerations entail sub-leading corrections in $Q^2$, dynamical higher twist effects, and hadron mass corrections. We also present novel calculations of several examples of flavor symmetry violation, which also originates in the long-distance properties of QCD at low energy. Moreover, we outline a recently developed model, framed as a hadronic effective theory amenable to QCD global analysis, which provides new insights into the possibility of nonperturbative heavy quarks in the nucleon. This model can be extended to the scale of the lighter mesons, and we assess the accessibility of the structure function of the interacting pion in the resulting framework.
[ { "created": "Sat, 23 Aug 2014 06:38:20 GMT", "version": "v1" } ]
2014-08-26
[ [ "Hobbs", "T. J.", "" ] ]
In this thesis we explore a diverse array of issues that strike at the inherently nonperturbative structure of hadrons at momenta below the QCD confinement scale. In so doing, we mainly seek a better control over the partonic substructure of strongly-interacting matter, especially as this relates to the nonperturbative effects that both motivate and complicate experiments --- particularly DIS; among others, such considerations entail sub-leading corrections in $Q^2$, dynamical higher twist effects, and hadron mass corrections. We also present novel calculations of several examples of flavor symmetry violation, which also originates in the long-distance properties of QCD at low energy. Moreover, we outline a recently developed model, framed as a hadronic effective theory amenable to QCD global analysis, which provides new insights into the possibility of nonperturbative heavy quarks in the nucleon. This model can be extended to the scale of the lighter mesons, and we assess the accessibility of the structure function of the interacting pion in the resulting framework.
1108.4344
Sergey Mikhailov
A. P. Bakulev, S. V. Mikhailov, A. V. Pimikov, N. G. Stefanis
Pion-photon transition form factor using light-cone sum rules: theoretical results, expectations, and a global-data fit
8pages, 6 Figures, 2 Tables. Talk presented by the second and third authors at the 5th joint International HADRON STRUCTURE '11 Conference, Tatranska Strba (Slovak Republic),June 27--July 1, 2011.v2 minor corrections, 3 references are added
Nucl. Phys. B (Proc. Suppl.) 219--220 (2011) 133--140
10.1016/j.nuclphysbps.2011.10.083
RUB-TPII-04/2011
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A global fit to the data from different collaborations (CELLO, CLEO, BaBar) on the pion-photon transition form factor is carried out using light-cone sum rules. The analysis includes the next-to-leading QCD radiative corrections and the twist-four contributions, while the main next-to-next-to-leading term and the twist-six contribution are taken into account in the form of theoretical uncertainties. We use the information extracted from the data to investigate the pivotal characteristics of the pion distribution amplitude. This is done by dividing the data into two sets: one containing all data up to 9 GeV$^2$, whereas the other incorporates also the high-$Q^2$ tail of the BaBar data. We find that it is not possible to accommodate into the fit these BaBar data points with the same accuracy and conclude that it is difficult to explain these data in the standard scheme of OCD.
[ { "created": "Mon, 22 Aug 2011 15:21:37 GMT", "version": "v1" }, { "created": "Fri, 26 Aug 2011 11:06:42 GMT", "version": "v2" } ]
2012-01-17
[ [ "Bakulev", "A. P.", "" ], [ "Mikhailov", "S. V.", "" ], [ "Pimikov", "A. V.", "" ], [ "Stefanis", "N. G.", "" ] ]
A global fit to the data from different collaborations (CELLO, CLEO, BaBar) on the pion-photon transition form factor is carried out using light-cone sum rules. The analysis includes the next-to-leading QCD radiative corrections and the twist-four contributions, while the main next-to-next-to-leading term and the twist-six contribution are taken into account in the form of theoretical uncertainties. We use the information extracted from the data to investigate the pivotal characteristics of the pion distribution amplitude. This is done by dividing the data into two sets: one containing all data up to 9 GeV$^2$, whereas the other incorporates also the high-$Q^2$ tail of the BaBar data. We find that it is not possible to accommodate into the fit these BaBar data points with the same accuracy and conclude that it is difficult to explain these data in the standard scheme of OCD.
2103.08511
Matti Heikinheimo
Sebastian Sassi, Abolfazl Dinmohammadi, Matti Heikinheimo, Nader Mirabolfathi, Kai Nordlund, Hossein Safari, Kimmo Tuominen
Solar neutrinos and dark matter detection with diurnal modulation
10 pages, 9 figures
Phys. Rev. D 104, 063037 (2021)
10.1103/PhysRevD.104.063037
HIP-2021-3/TH
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate the diurnal modulation of the event rate for dark matter scattering on solid targets arising from the directionally dependent defect creation threshold energy. In particular, we quantify how this effect would help in separating dark matter signal from the neutrino background. We perform a benchmark analysis for a germanium detector and compute how the reach of the experiment is affected by including the timing information of the scattering events. We observe that for light dark matter just above the detection threshold the magnitude of the annual modulation is enhanced. In this mass range using either the annual or diurnal modulation information provides a similar gain in the reach of the experiment, while the additional reach from using both effects remains modest. Furthermore, we demonstrate that if the background contains a feature exhibiting an annual modulation similar to the one observed by DAMA experiment, the diurnal modulation provides for an additional handle to separate dark matter signal from the background.
[ { "created": "Mon, 15 Mar 2021 16:35:18 GMT", "version": "v1" }, { "created": "Sun, 18 Apr 2021 12:28:59 GMT", "version": "v2" } ]
2021-09-29
[ [ "Sassi", "Sebastian", "" ], [ "Dinmohammadi", "Abolfazl", "" ], [ "Heikinheimo", "Matti", "" ], [ "Mirabolfathi", "Nader", "" ], [ "Nordlund", "Kai", "" ], [ "Safari", "Hossein", "" ], [ "Tuominen", "Kimmo", ...
We investigate the diurnal modulation of the event rate for dark matter scattering on solid targets arising from the directionally dependent defect creation threshold energy. In particular, we quantify how this effect would help in separating dark matter signal from the neutrino background. We perform a benchmark analysis for a germanium detector and compute how the reach of the experiment is affected by including the timing information of the scattering events. We observe that for light dark matter just above the detection threshold the magnitude of the annual modulation is enhanced. In this mass range using either the annual or diurnal modulation information provides a similar gain in the reach of the experiment, while the additional reach from using both effects remains modest. Furthermore, we demonstrate that if the background contains a feature exhibiting an annual modulation similar to the one observed by DAMA experiment, the diurnal modulation provides for an additional handle to separate dark matter signal from the background.
hep-ph/9302321
null
Fred C. Adams
General Solutions for Tunneling of Scalar Fields with Quartic Potentials
17 pages, 6 figures not included but available upon request, UM AC 93-4
Phys.Rev. D48 (1993) 2800-2805
10.1103/PhysRevD.48.2800
null
hep-ph
null
For the theory of a single scalar field $\varphi$ with a quartic potential $V(\varphi)$, we find semi-analytic expressions for the Euclidean action in both four and three dimensions. The action in four dimensions determines the quantum tunneling rate at zero temperature from a false vacuum state to the true vacuum state; similarly, the action in three dimensions determines the thermal tunneling rate for a finite temperature theory. We show that for all quartic potentials, the action can be obtained from a one parameter family of instanton solutions corresponding to a one parameter family of differential equations. We find the solutions numerically and use polynomial fitting formulae to obtain expressions for the Euclidean action. These results allow one to calculate tunneling rates for the entire possible range of quartic potentials, from the thin-wall (nearly degenerate) limit to the opposite limit of vanishing barrier height. We also present a similar calculation for potentials containing $\varphi^4 \ln \varphi^2$ terms, which arise in the one-loop approximation to the effective potential in electroweak theory.
[ { "created": "Sun, 28 Feb 1993 18:53:17 GMT", "version": "v1" } ]
2009-10-22
[ [ "Adams", "Fred C.", "" ] ]
For the theory of a single scalar field $\varphi$ with a quartic potential $V(\varphi)$, we find semi-analytic expressions for the Euclidean action in both four and three dimensions. The action in four dimensions determines the quantum tunneling rate at zero temperature from a false vacuum state to the true vacuum state; similarly, the action in three dimensions determines the thermal tunneling rate for a finite temperature theory. We show that for all quartic potentials, the action can be obtained from a one parameter family of instanton solutions corresponding to a one parameter family of differential equations. We find the solutions numerically and use polynomial fitting formulae to obtain expressions for the Euclidean action. These results allow one to calculate tunneling rates for the entire possible range of quartic potentials, from the thin-wall (nearly degenerate) limit to the opposite limit of vanishing barrier height. We also present a similar calculation for potentials containing $\varphi^4 \ln \varphi^2$ terms, which arise in the one-loop approximation to the effective potential in electroweak theory.
2007.04506
Braden Kronheim
Braden Kronheim, Michelle Kuchera, Harrison Prosper, and Alexander Karbo
Bayesian Neural Networks for Fast SUSY Predictions
null
Phys. Let. B 813 (2021) 136041
10.1016/j.physletb.2020.136041
null
hep-ph cs.LG physics.comp-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
One of the goals of current particle physics research is to obtain evidence for new physics, that is, physics beyond the Standard Model (BSM), at accelerators such as the Large Hadron Collider (LHC) at CERN. The searches for new physics are often guided by BSM theories that depend on many unknown parameters, which, in some cases, makes testing their predictions difficult. In this paper, machine learning is used to model the mapping from the parameter space of the phenomenological Minimal Supersymmetric Standard Model (pMSSM), a BSM theory with 19 free parameters, to some of its predictions. Bayesian neural networks are used to predict cross sections for arbitrary pMSSM parameter points, the mass of the associated lightest neutral Higgs boson, and the theoretical viability of the parameter points. All three quantities are modeled with average percent errors of 3.34% or less and in a time significantly shorter than is possible with the supersymmetry codes from which the results are derived. These results are a further demonstration of the potential for machine learning to model accurately the mapping from the high dimensional spaces of BSM theories to their predictions.
[ { "created": "Thu, 9 Jul 2020 01:45:06 GMT", "version": "v1" }, { "created": "Mon, 13 Jul 2020 17:58:11 GMT", "version": "v2" }, { "created": "Sat, 12 Dec 2020 01:51:38 GMT", "version": "v3" } ]
2022-07-12
[ [ "Kronheim", "Braden", "" ], [ "Kuchera", "Michelle", "" ], [ "Prosper", "Harrison", "" ], [ "Karbo", "Alexander", "" ] ]
One of the goals of current particle physics research is to obtain evidence for new physics, that is, physics beyond the Standard Model (BSM), at accelerators such as the Large Hadron Collider (LHC) at CERN. The searches for new physics are often guided by BSM theories that depend on many unknown parameters, which, in some cases, makes testing their predictions difficult. In this paper, machine learning is used to model the mapping from the parameter space of the phenomenological Minimal Supersymmetric Standard Model (pMSSM), a BSM theory with 19 free parameters, to some of its predictions. Bayesian neural networks are used to predict cross sections for arbitrary pMSSM parameter points, the mass of the associated lightest neutral Higgs boson, and the theoretical viability of the parameter points. All three quantities are modeled with average percent errors of 3.34% or less and in a time significantly shorter than is possible with the supersymmetry codes from which the results are derived. These results are a further demonstration of the potential for machine learning to model accurately the mapping from the high dimensional spaces of BSM theories to their predictions.
hep-ph/0302028
Maxim V. Polyakov
K. Goeke, A. Metz, P.V. Pobylitsa and M.V. Polyakov
Lorentz invariance relations among parton distributions revisited
4 pages, minor changes, to appear in Phys. Lett. B
Phys.Lett. B567 (2003) 27-30
10.1016/S0370-2693(03)00870-0
null
hep-ph
null
We revisit the derivation of the so-called Lorentz invariance relations between parton distributions. In the most important cases these relations involve twist-3 and transverse momentum dependent parton distributions. It is shown that these relations are violated if the path-ordered exponential is taken into account in the quark correlator.
[ { "created": "Tue, 4 Feb 2003 17:32:13 GMT", "version": "v1" }, { "created": "Mon, 16 Jun 2003 13:42:33 GMT", "version": "v2" } ]
2009-11-10
[ [ "Goeke", "K.", "" ], [ "Metz", "A.", "" ], [ "Pobylitsa", "P. V.", "" ], [ "Polyakov", "M. V.", "" ] ]
We revisit the derivation of the so-called Lorentz invariance relations between parton distributions. In the most important cases these relations involve twist-3 and transverse momentum dependent parton distributions. It is shown that these relations are violated if the path-ordered exponential is taken into account in the quark correlator.
1007.4807
Duccio Pappadopulo
Duccio Pappadopulo and Alessandro Vichi
T-parity, its problems and their solution
25 pages, 2 appendices
JHEP 1103:072,2011
10.1007/JHEP03(2011)072
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We point out a basic difficulty in the construction of little-Higgs models with T-parity which is overlooked by large part of the present literature. Almost all models proposed so far fail to achieve their goal: they either suffer from sizable electroweak corrections or from a breakdown of collective breaking. We provide a model building recipe to bypass the above problem and apply it to build the simplest T-invariant extension of the Littlest Higgs. Our model predicts additional T-odd pseudo-Goldstone bosons with weak scale masses.
[ { "created": "Tue, 27 Jul 2010 20:00:02 GMT", "version": "v1" } ]
2011-03-21
[ [ "Pappadopulo", "Duccio", "" ], [ "Vichi", "Alessandro", "" ] ]
We point out a basic difficulty in the construction of little-Higgs models with T-parity which is overlooked by large part of the present literature. Almost all models proposed so far fail to achieve their goal: they either suffer from sizable electroweak corrections or from a breakdown of collective breaking. We provide a model building recipe to bypass the above problem and apply it to build the simplest T-invariant extension of the Littlest Higgs. Our model predicts additional T-odd pseudo-Goldstone bosons with weak scale masses.
1206.1033
Juan Antonio Aguilar-Saavedra
J. A. Aguilar-Saavedra, M. C. N. Fiolhais, A. Onofre
Top effective operators at the ILC
LaTeX 13 pages. Typos corrected. Final version in JHEP
null
10.1007/JHEP07(2012)180
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate the effect of top trilinear operators in t tbar production at the ILC. We find that the sensitivity to these operators largely surpasses the one achievable by the LHC either in neutral or charged current processes, allowing to probe new physics scales up to 4.5 TeV for a centre of mass energy of 500 GeV. We show how the use of beam polarisation and an eventual energy upgrade to 1 TeV allow to disentangle all effective operator contributions to the Ztt and gamma tt vertices.
[ { "created": "Tue, 5 Jun 2012 19:30:55 GMT", "version": "v1" }, { "created": "Mon, 30 Jul 2012 07:23:34 GMT", "version": "v2" } ]
2017-08-23
[ [ "Aguilar-Saavedra", "J. A.", "" ], [ "Fiolhais", "M. C. N.", "" ], [ "Onofre", "A.", "" ] ]
We investigate the effect of top trilinear operators in t tbar production at the ILC. We find that the sensitivity to these operators largely surpasses the one achievable by the LHC either in neutral or charged current processes, allowing to probe new physics scales up to 4.5 TeV for a centre of mass energy of 500 GeV. We show how the use of beam polarisation and an eventual energy upgrade to 1 TeV allow to disentangle all effective operator contributions to the Ztt and gamma tt vertices.
hep-ph/9410252
null
B.V.Geshkenbein, V.L.Morgunov
Hadronic contributions to the anomalous magnetic moment of the muon by QCD model with infinite number of vector mesons
in LaTeX, 7 pages, ITEP preprint 70-94
null
null
null
hep-ph
null
We computed the hadronic vacuum-polarization contributions to the muon anomalous magnetic moment $a_{\mu}(hadr.)$ by using the QCD model with infinite number of vector mesons [1,2]. The result is $a_{\mu}(hadr.) = 663(23) \times 10^{-10}$. }
[ { "created": "Mon, 10 Oct 1994 10:54:02 GMT", "version": "v1" } ]
2007-05-23
[ [ "Geshkenbein", "B. V.", "" ], [ "Morgunov", "V. L.", "" ] ]
We computed the hadronic vacuum-polarization contributions to the muon anomalous magnetic moment $a_{\mu}(hadr.)$ by using the QCD model with infinite number of vector mesons [1,2]. The result is $a_{\mu}(hadr.) = 663(23) \times 10^{-10}$. }
1908.03494
Martin Hentschinski
Martin Hentschinski and Krzysztof Kutak
Signs for the onset of gluon saturation in exclusive photo-production of vector mesons
7 pages, 6 figures. To appear in the Proceedings of the 7th Annual Conference on Large Hadron Collider Physics - LHCP2019 20-25 May, 2019 Puebla, Mexico
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate the energy dependence of the photo-production cross-section of vector mesons $J/\Psi$ and $\Upsilon$, measured by both HERA experiments H1 and ZEUS in electron-proton collisions and by LHC experiments ALICE, CMS and LHCb in ultra-peripheral proton-proton and ultra-peripheral proton-lead collisions. Our study uses 2 particular fits of inclusive unintegrated gluon distribution, based on non-linear Balitsky-Kovchegov evolution (Kutak-Sapeta gluon; KS) and next-to-leading order Balitsky-Fadin-Kuraev-Lipatov evolution (Hentschinski-Sabio Vera-Salas gluon; HSS). We find that linear next-to-leading order BFKL evolution can only describe production at highest energies, if perturbative corrections are increased to unnaturally large values; rendering this corrections small, the growth with energy is too strong in the LHC region and the description of $J/\Psi$ data fails. For the KS gluon we find that an accurate description of $J/\Psi$ data is possible if non-linear corrections to low x QCD evolution are taken into account; without such correction a description of data fails. We interpret this observation as a clear signal for the presence of high gluon densities in low x the proton, characteristic for the onset of gluon saturation.
[ { "created": "Fri, 9 Aug 2019 15:31:33 GMT", "version": "v1" } ]
2019-08-12
[ [ "Hentschinski", "Martin", "" ], [ "Kutak", "Krzysztof", "" ] ]
We investigate the energy dependence of the photo-production cross-section of vector mesons $J/\Psi$ and $\Upsilon$, measured by both HERA experiments H1 and ZEUS in electron-proton collisions and by LHC experiments ALICE, CMS and LHCb in ultra-peripheral proton-proton and ultra-peripheral proton-lead collisions. Our study uses 2 particular fits of inclusive unintegrated gluon distribution, based on non-linear Balitsky-Kovchegov evolution (Kutak-Sapeta gluon; KS) and next-to-leading order Balitsky-Fadin-Kuraev-Lipatov evolution (Hentschinski-Sabio Vera-Salas gluon; HSS). We find that linear next-to-leading order BFKL evolution can only describe production at highest energies, if perturbative corrections are increased to unnaturally large values; rendering this corrections small, the growth with energy is too strong in the LHC region and the description of $J/\Psi$ data fails. For the KS gluon we find that an accurate description of $J/\Psi$ data is possible if non-linear corrections to low x QCD evolution are taken into account; without such correction a description of data fails. We interpret this observation as a clear signal for the presence of high gluon densities in low x the proton, characteristic for the onset of gluon saturation.
hep-ph/0101236
Yukinari Sumino
Y. Sumino
Toward Determination of m_t at 50 MeV Accuracy
5 pages, 2 figures, Talk given at the Linear Colliders Workshop 2000, Fermilab, USA, October 2000
null
10.1063/1.1394335
TU-609
hep-ph
null
The top quark mass will be determined to high accuracy from the shape of the ttbar total production cross section in the threshold region at a future linear e+e- collider. Presently the estimated statistical error in the measurement of the MSbar mass of the top quark is \sim 50 MeV, while the estimated theoretical error is 150-200 MeV. In order to reduce the theoretical uncertainty to below 50 MeV, we have recently computed an important part of the higher-order corrections. We deomonstrate the significance of the calculated correction.
[ { "created": "Mon, 22 Jan 2001 08:45:26 GMT", "version": "v1" } ]
2009-11-07
[ [ "Sumino", "Y.", "" ] ]
The top quark mass will be determined to high accuracy from the shape of the ttbar total production cross section in the threshold region at a future linear e+e- collider. Presently the estimated statistical error in the measurement of the MSbar mass of the top quark is \sim 50 MeV, while the estimated theoretical error is 150-200 MeV. In order to reduce the theoretical uncertainty to below 50 MeV, we have recently computed an important part of the higher-order corrections. We deomonstrate the significance of the calculated correction.
hep-ph/0009297
Ivan Schmidt
Bo-Qiang Ma, Ivan Schmidt, and Jian-Jun Yang
Nucleon Transversity Distribution from Azimuthal Spin Asymmetry in Pion Electroproduction
11 latex pages, 1 figure, version to appear in PRD
Phys.Rev. D63 (2001) 037501
10.1103/PhysRevD.63.037501
USM-TH-99
hep-ph hep-ex nucl-ex nucl-th
null
The azimuthal asymmetry observed by the HERMES collaboration in semi-inclusive pion production in deep inelastic scattering of unpolarized positron on the longitudinally polarized proton target, can provide information of the quark transversity distributions of the nucleon. We show that the quark transversity distributions predicted both by the light-cone quark-spectator-diquark model and by a pQCD inspired model can give consistent descriptions of the available HERMES data for the analyzing powers $A_{UL}^{\sin \phi}$ and $A_{UL}^{\sin 2 \phi}$ for $\pi^+$ and $\pi^-$ productions. We also show that the two models give similar predictions of $A_{UL}^{\sin \phi}$ for $\pi^+$ production, whereas they give very different predictions of $A_{UL}^{\sin \phi}$ for $\pi^-$ production at large $x$. Further precision measurement of $A_{UL}^{\sin \phi}$ for $\pi^-$ production can provide a decisive test of different models.
[ { "created": "Tue, 26 Sep 2000 14:00:56 GMT", "version": "v1" }, { "created": "Tue, 21 Nov 2000 18:13:38 GMT", "version": "v2" } ]
2009-10-31
[ [ "Ma", "Bo-Qiang", "" ], [ "Schmidt", "Ivan", "" ], [ "Yang", "Jian-Jun", "" ] ]
The azimuthal asymmetry observed by the HERMES collaboration in semi-inclusive pion production in deep inelastic scattering of unpolarized positron on the longitudinally polarized proton target, can provide information of the quark transversity distributions of the nucleon. We show that the quark transversity distributions predicted both by the light-cone quark-spectator-diquark model and by a pQCD inspired model can give consistent descriptions of the available HERMES data for the analyzing powers $A_{UL}^{\sin \phi}$ and $A_{UL}^{\sin 2 \phi}$ for $\pi^+$ and $\pi^-$ productions. We also show that the two models give similar predictions of $A_{UL}^{\sin \phi}$ for $\pi^+$ production, whereas they give very different predictions of $A_{UL}^{\sin \phi}$ for $\pi^-$ production at large $x$. Further precision measurement of $A_{UL}^{\sin \phi}$ for $\pi^-$ production can provide a decisive test of different models.
hep-ph/9810514
Nick Evans
Nick Evans (Boston U.), Stephen Hsu (U. Oregon), Myckola Schwetz (Rutgers)
Non-Perturbative Couplings and Color Superconductivity
10 pages, LaTeX, 4 eps files, extra discussion
Phys.Lett. B449 (1999) 281-287
10.1016/S0370-2693(99)00093-3
null
hep-ph hep-th nucl-th
null
Quark matter at sufficiently high density exhibits color superconductivity, due to attractive gluonic interactions. At lower densities of order $\Lambda_{QCD}^3$, it has been proposed that instanton generated vertices may play an important role in the Cooper pair formation. We study the renormalization group flow to the Fermi surface of the full set of couplings generated by gluonic and instanton interactions. In earlier work we showed that if the gluonic interactions dominate at the matching scale, their running determines the scale of the Cooper pair formation Delta. Here we consider all possibilities, including the one in which the instanton interactions dominate all others at the matching scale. In the latter case we find that a number of additional induced couplings (including the gluonic ones) reach their Landau poles almost simultaneously with the instanton vertex. Presumably all contribute to the Cooper pair formation. The most important consequence of including all the couplings is a large increase in the gap size Delta.
[ { "created": "Wed, 28 Oct 1998 22:47:15 GMT", "version": "v1" }, { "created": "Wed, 20 Jan 1999 18:20:45 GMT", "version": "v2" } ]
2009-10-31
[ [ "Evans", "Nick", "", "Boston U." ], [ "Hsu", "Stephen", "", "U. Oregon" ], [ "Schwetz", "Myckola", "", "Rutgers" ] ]
Quark matter at sufficiently high density exhibits color superconductivity, due to attractive gluonic interactions. At lower densities of order $\Lambda_{QCD}^3$, it has been proposed that instanton generated vertices may play an important role in the Cooper pair formation. We study the renormalization group flow to the Fermi surface of the full set of couplings generated by gluonic and instanton interactions. In earlier work we showed that if the gluonic interactions dominate at the matching scale, their running determines the scale of the Cooper pair formation Delta. Here we consider all possibilities, including the one in which the instanton interactions dominate all others at the matching scale. In the latter case we find that a number of additional induced couplings (including the gluonic ones) reach their Landau poles almost simultaneously with the instanton vertex. Presumably all contribute to the Cooper pair formation. The most important consequence of including all the couplings is a large increase in the gap size Delta.
0704.2165
Per Osland
P. Osland and A. Vereshagin
CP violation in unpolarized e^+ e^- to charginos at one loop level
similar to Phys. Rev. D version, but corrected figs. 4, 5, 6 (factor four)
Phys.Rev.D76:036001,2007; Erratum-ibid.D76:036001,2007
10.1103/PhysRevD.76.036001
null
hep-ph
null
We study CP violation in e^+ e^- to \tilde\chi_i^+\tilde\chi_j^- in the framework of the MSSM. Though the cross section of this process is CP-even at the tree level even for polarized electron-positron beams, we show that it contains a CP-odd part at the one loop order and there are CP-odd observables that can in principle be measured even using unpolarized electron-positron beams. The relevant diagram calculations are briefly discussed and the results of selected (box) diagram computations are shown.
[ { "created": "Tue, 17 Apr 2007 14:45:58 GMT", "version": "v1" }, { "created": "Wed, 27 Jun 2007 19:15:04 GMT", "version": "v2" }, { "created": "Thu, 4 Oct 2007 11:48:11 GMT", "version": "v3" } ]
2008-11-26
[ [ "Osland", "P.", "" ], [ "Vereshagin", "A.", "" ] ]
We study CP violation in e^+ e^- to \tilde\chi_i^+\tilde\chi_j^- in the framework of the MSSM. Though the cross section of this process is CP-even at the tree level even for polarized electron-positron beams, we show that it contains a CP-odd part at the one loop order and there are CP-odd observables that can in principle be measured even using unpolarized electron-positron beams. The relevant diagram calculations are briefly discussed and the results of selected (box) diagram computations are shown.
1506.05742
Sergio Scopetta
M. Rinaldi, S. Scopetta, M. Traini, V. Vento
Double parton scattering: a study of the effective cross section within a Light-Front quark model
11 pages, 3 figures
null
10.1016/j.physletb.2015.11.031
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a calculation of the effective cross section $\sigma_{eff}$, an important ingredient in the description of double parton scattering in proton-proton collisions. Our theoretical approach makes use of a Light-Front quark model as framework to calculate the double parton distribution functions at low-resolution scale. QCD evolution is implemented to reach the experimental scale. The obtained $\sigma_{eff}$, when averaged over the longitudinal momentum fractions of the interacting partons, $x_i$, is consistent with the present experimental scenario. However the result of the complete calculation shows a dependence of $\sigma_{eff}$ on $x_i$, a feature not easily seen in the available data, probably because of their low accuracy. Measurements of $\sigma_{eff}$ in restricted $x_i$ regions are addressed to obtain indications on double parton correlations, a novel and interesting aspect of the three dimensional structure of the nucleon.
[ { "created": "Thu, 18 Jun 2015 16:31:40 GMT", "version": "v1" } ]
2015-12-09
[ [ "Rinaldi", "M.", "" ], [ "Scopetta", "S.", "" ], [ "Traini", "M.", "" ], [ "Vento", "V.", "" ] ]
We present a calculation of the effective cross section $\sigma_{eff}$, an important ingredient in the description of double parton scattering in proton-proton collisions. Our theoretical approach makes use of a Light-Front quark model as framework to calculate the double parton distribution functions at low-resolution scale. QCD evolution is implemented to reach the experimental scale. The obtained $\sigma_{eff}$, when averaged over the longitudinal momentum fractions of the interacting partons, $x_i$, is consistent with the present experimental scenario. However the result of the complete calculation shows a dependence of $\sigma_{eff}$ on $x_i$, a feature not easily seen in the available data, probably because of their low accuracy. Measurements of $\sigma_{eff}$ in restricted $x_i$ regions are addressed to obtain indications on double parton correlations, a novel and interesting aspect of the three dimensional structure of the nucleon.
hep-ph/0608325
Matthias Schindler
M. R. Schindler, S. Scherer
Nucleon Form Factors of the Isovector Axial-Vector Current: Situation of Experiments and Theory
5 pages, 3 figures. Talk given by M. R. Schindler at the International Workshop "From Parity Violation to Hadronic Structure and more...", Milos, Greece, May 16-20, 2006
Eur.Phys.J.A32:429-433,2007
10.1140/epja/i2006-10403-3
MKPH-T-06-15
hep-ph
null
The theoretical and experimental status of the isovector axial-vector current form factors G_A(q^2) and G_P(q^2) of the nucleon is reviewed. We also describe a new calculation of these form factors in manifestly Lorentz-invariant chiral perturbation theory (ChPT) with the inclusion of axial-vector mesons as explicit degrees of freedom.
[ { "created": "Wed, 30 Aug 2006 15:51:04 GMT", "version": "v1" } ]
2008-11-26
[ [ "Schindler", "M. R.", "" ], [ "Scherer", "S.", "" ] ]
The theoretical and experimental status of the isovector axial-vector current form factors G_A(q^2) and G_P(q^2) of the nucleon is reviewed. We also describe a new calculation of these form factors in manifestly Lorentz-invariant chiral perturbation theory (ChPT) with the inclusion of axial-vector mesons as explicit degrees of freedom.
1201.1275
David Wilson
D. J. Wilson and M. R. Pennington
Vertex Sensitivity in the Schwinger-Dyson Equations of QCD
12 pages, 8 figures. Contribution to the International Workshop on QCD Green's Functions, Confinement and Phenomenology, September 5-9 2011, Trento, Italy
PoS(QCD-TNT-II)052, 2011
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The non-perturbative gluon and ghost propagators in Landau gauge QCD are obtained using the Schwinger-Dyson equation approach. The propagator equations are solved in Euclidean space using Landau gauge with a range of vertex inputs. Initially we solve for the ghost alone, using a model gluon input, which leads us to favour a finite ghost dressing in the non-perturbative region. In order to then solve the gluon and ghost equations simultaneously, we find that non-trivial vertices are required, particularly for the gluon propagator in the small momentum limit. We focus on the properties of a number vertices and how these differences influence the final solutions. The self-consistent solutions we obtain are all qualitatively similar and contain a masslike term in the gluon propagator dressing in agreement with related studies, supporting the long-held proposal of Cornwall.
[ { "created": "Thu, 5 Jan 2012 20:14:42 GMT", "version": "v1" } ]
2015-03-19
[ [ "Wilson", "D. J.", "" ], [ "Pennington", "M. R.", "" ] ]
The non-perturbative gluon and ghost propagators in Landau gauge QCD are obtained using the Schwinger-Dyson equation approach. The propagator equations are solved in Euclidean space using Landau gauge with a range of vertex inputs. Initially we solve for the ghost alone, using a model gluon input, which leads us to favour a finite ghost dressing in the non-perturbative region. In order to then solve the gluon and ghost equations simultaneously, we find that non-trivial vertices are required, particularly for the gluon propagator in the small momentum limit. We focus on the properties of a number vertices and how these differences influence the final solutions. The self-consistent solutions we obtain are all qualitatively similar and contain a masslike term in the gluon propagator dressing in agreement with related studies, supporting the long-held proposal of Cornwall.
0707.1323
Jure Zupan
Jure Zupan
Predictions for sin 2(beta/phi_1)_eff in b->s penguin dominated modes
7 pages, 6 figures, talk at Flavor Physics and CP Violation Conference, Bled, 2007, referencing improved
ECONFC070512:012,2007
null
null
hep-ph
null
We provide a review of predictions for sin 2beta_eff in b->s penguin dominated modes based on 1/m_b expansion and/or SU(3) flavor symmetry. The experimental results are consistently lower than the theoretical predictions. In order to interpret whether this effect is a sign of new physics contributions or can be explained away within the Standard Model a theoretical input cannot be avoided. The effect survives at a level larger than 2.1 sigma in a conservative average over different modes that includes theoretical predictions.
[ { "created": "Mon, 9 Jul 2007 19:44:28 GMT", "version": "v1" }, { "created": "Wed, 19 Sep 2007 14:01:46 GMT", "version": "v2" } ]
2008-11-26
[ [ "Zupan", "Jure", "" ] ]
We provide a review of predictions for sin 2beta_eff in b->s penguin dominated modes based on 1/m_b expansion and/or SU(3) flavor symmetry. The experimental results are consistently lower than the theoretical predictions. In order to interpret whether this effect is a sign of new physics contributions or can be explained away within the Standard Model a theoretical input cannot be avoided. The effect survives at a level larger than 2.1 sigma in a conservative average over different modes that includes theoretical predictions.
hep-ph/0003096
Thorsten Feldmann
Th. Feldmann (RWTH Aachen), P. Kroll (Wuppertal Univ.)
Implications of light-quark admixtures on charmonium decays into meson pairs
21 pages, 3 figures (using epsfig.sty, a4wide.sty); v2 contains minor changes (1 paragraph in Sec.II and a few references added)
Phys.Rev.D62:074006,2000
10.1103/PhysRevD.62.074006
WU-B 00--01, PITHA 00/05
hep-ph hep-ex
null
We argue that charmonium decays into meson pairs fall into two distinct classes: one that is under control of perturbative QCD and another one that is governed by a soft mechanism. We concentrate on a systematic analysis of J/Psi (Psi') decays into a light pseudoscalar and a light vector meson and eta(c) decays into a pair of light vector mesons. These processes belong to the second class and are characterized by non-conserved hadronic helicity. It is assumed that, in these cases, the charmonium state decays dominantly through a light-quark Fock component by a soft mechanism which is characteristic of OZI-rule allowed strong decays. Estimating the light-quark admixture by meson mixing, we obtain a reasonable description of the branching ratios for these processes.
[ { "created": "Fri, 10 Mar 2000 13:03:40 GMT", "version": "v1" }, { "created": "Wed, 26 Jul 2000 07:57:03 GMT", "version": "v2" } ]
2009-08-25
[ [ "Feldmann", "Th.", "", "RWTH Aachen" ], [ "Kroll", "P.", "", "Wuppertal Univ." ] ]
We argue that charmonium decays into meson pairs fall into two distinct classes: one that is under control of perturbative QCD and another one that is governed by a soft mechanism. We concentrate on a systematic analysis of J/Psi (Psi') decays into a light pseudoscalar and a light vector meson and eta(c) decays into a pair of light vector mesons. These processes belong to the second class and are characterized by non-conserved hadronic helicity. It is assumed that, in these cases, the charmonium state decays dominantly through a light-quark Fock component by a soft mechanism which is characteristic of OZI-rule allowed strong decays. Estimating the light-quark admixture by meson mixing, we obtain a reasonable description of the branching ratios for these processes.
hep-ph/0010206
Kayser
Boris Kayser
Neutrino Mass: The Present and the Future
LaTeX, 6 pages, 4 embedded figures
null
null
null
hep-ph
null
We argue that the evidence for neutrino mass is quite compelling. This mass raises a number of questions, which we enumerate, about neutrinos. Then we focus on one of these questions---the issue of the possible neutrino mass spectra. In particular, we explain that one can have a four-neutrino spectrum which does not require significant sterile-neutrino involvement in either the atmospheric or solar neutrino oscillations.
[ { "created": "Wed, 18 Oct 2000 15:36:57 GMT", "version": "v1" } ]
2007-05-23
[ [ "Kayser", "Boris", "" ] ]
We argue that the evidence for neutrino mass is quite compelling. This mass raises a number of questions, which we enumerate, about neutrinos. Then we focus on one of these questions---the issue of the possible neutrino mass spectra. In particular, we explain that one can have a four-neutrino spectrum which does not require significant sterile-neutrino involvement in either the atmospheric or solar neutrino oscillations.
hep-ph/9405283
null
A. Ali and D. London
Implications of the Top Quark Mass Measurements for the CKM Parameters, $\xs$ and CP Asymmetries
18 pages and 5 figures (not included, can be obtained by request), LaTeX, CERN Report, CERN-TH.7248/94 (May 1994); UdeM-LPN-TH-94-117. (Corrected version; typos corrected in section 6 in the line following Eq. (34).)
Z.Phys. C65 (1995) 431-443
null
null
hep-ph
null
Motivated by the recent determination of the top quark mass by the CDF collaboration, $\mt =174 \pm 10 ^{+13}_{-12}$ GeV, we review and update constraints on the parameters of the quark flavour mixing matrix $V_{CKM}$ in the standard model. In performing these fits, we use inputs from the measurements of $\abseps$, the CP-violating parameter in $K$ decays, $\xd = (\delm)/\Gamma$, the mixing parameter in \bdbdbar\ mixing, the present measurements of the matrix elements $\absvcb$ and $\absvub$, and the $B$-hadron lifetimes. The CDF value for $\mt$ considerably reduces the CKM-parameter space previously allowed. An interesting result of our analysis is that the present data can be used to restrict the coupling constant product ratio $f_{B_d}\sqrt{B_{B_d}}$ to the range 110-270 MeV -- in comfortable agreement with existing theoretical estimates of this quantity. We use the updated CKM matrix to predict the \bsbsbar\ mixing ratio $\xs$, as well as the quantities $\sin 2\alpha$, $\sin 2\beta$ and $\sin^2\gamma$, which characterize CP-violating asymmetries in $B$-decays.
[ { "created": "Fri, 13 May 1994 17:56:34 GMT", "version": "v1" }, { "created": "Sat, 14 May 1994 15:39:50 GMT", "version": "v2" } ]
2009-09-25
[ [ "Ali", "A.", "" ], [ "London", "D.", "" ] ]
Motivated by the recent determination of the top quark mass by the CDF collaboration, $\mt =174 \pm 10 ^{+13}_{-12}$ GeV, we review and update constraints on the parameters of the quark flavour mixing matrix $V_{CKM}$ in the standard model. In performing these fits, we use inputs from the measurements of $\abseps$, the CP-violating parameter in $K$ decays, $\xd = (\delm)/\Gamma$, the mixing parameter in \bdbdbar\ mixing, the present measurements of the matrix elements $\absvcb$ and $\absvub$, and the $B$-hadron lifetimes. The CDF value for $\mt$ considerably reduces the CKM-parameter space previously allowed. An interesting result of our analysis is that the present data can be used to restrict the coupling constant product ratio $f_{B_d}\sqrt{B_{B_d}}$ to the range 110-270 MeV -- in comfortable agreement with existing theoretical estimates of this quantity. We use the updated CKM matrix to predict the \bsbsbar\ mixing ratio $\xs$, as well as the quantities $\sin 2\alpha$, $\sin 2\beta$ and $\sin^2\gamma$, which characterize CP-violating asymmetries in $B$-decays.
0712.3756
Michael Maziashvili
Michael Maziashvili
Dark energy due to effective quantum field theory
4 pages; Version to appear in PLB
Phys.Lett.B663:7-10,2008
10.1016/j.physletb.2008.03.044
null
hep-ph astro-ph gr-qc hep-th
null
In the cosmological context an effective quantum field theory describing the behavior of visible matter in the universe is characterized with its inherent UV cutoff and also with an IR scale that is set by the cosmological (particle) horizon. This UV - IR relation naturally defines a space-time grid over a horizon scale. Using the approach for determining of dark energy through the space-time uncertainty relation versus such a space-time grid, we estimate the energy density and pressure of a dark energy defined by this UV - IR relation. Such a dark energy shows up to decay linearly with time and exhibits a negative pressure only recently.
[ { "created": "Fri, 21 Dec 2007 17:31:18 GMT", "version": "v1" }, { "created": "Mon, 24 Dec 2007 21:52:21 GMT", "version": "v2" }, { "created": "Mon, 31 Mar 2008 05:45:03 GMT", "version": "v3" } ]
2008-11-26
[ [ "Maziashvili", "Michael", "" ] ]
In the cosmological context an effective quantum field theory describing the behavior of visible matter in the universe is characterized with its inherent UV cutoff and also with an IR scale that is set by the cosmological (particle) horizon. This UV - IR relation naturally defines a space-time grid over a horizon scale. Using the approach for determining of dark energy through the space-time uncertainty relation versus such a space-time grid, we estimate the energy density and pressure of a dark energy defined by this UV - IR relation. Such a dark energy shows up to decay linearly with time and exhibits a negative pressure only recently.
1301.4469
Antoni Szczurek
Rafal Maciula and Antoni Szczurek
Production of $c \bar c c \bar c$ in double-parton scattering within $k_{t}$-factorization approach -- meson-meson correlations
15 pages, 12 figures
null
10.1103/PhysRevD.87.074039
null
hep-ph hep-ex nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We discuss production of two pairs of $c \bar c$ in proton-proton collisions at the LHC. Both double-parton scattering (DPS) and single-parton scattering (SPS) contributions are included in the analysis. Each step of DPS is calculated within $k_t$-factorization approach, i.e. effectively including next-to-leading order corrections. The conditions how to identify the DPS contribution are presented. The discussed mechanism unavoidably leads to the production of pairs of mesons: $D_i D_j$ (each containing $c$ quarks) or $\bar D_i \bar D_j$ (each containing $\bar c$ antiquarks). We calculate corresponding production rates for different combinations of charmed mesons as well as some differential distribution for $(D^0 D^0$ + $\bar D^0 \bar D^0)$ production. Within large theoretical uncertainties the predicted DPS cross section is fairly similar to the cross section measured recently by the LHCb collaboration. The best description is obtained with the Kimber-Martin-Ryskin (KMR) unintegrated gluon distribution, which very well simulates higher-order corrections. The contribution of SPS, calculated in the high-energy approximation, turned out to be rather small. Finally, we emphasize significant contribution of DPS mechanism to inclusive charmed meson spectra measured recently by ALICE, ATLAS and LHCb.
[ { "created": "Fri, 18 Jan 2013 19:15:23 GMT", "version": "v1" } ]
2013-05-08
[ [ "Maciula", "Rafal", "" ], [ "Szczurek", "Antoni", "" ] ]
We discuss production of two pairs of $c \bar c$ in proton-proton collisions at the LHC. Both double-parton scattering (DPS) and single-parton scattering (SPS) contributions are included in the analysis. Each step of DPS is calculated within $k_t$-factorization approach, i.e. effectively including next-to-leading order corrections. The conditions how to identify the DPS contribution are presented. The discussed mechanism unavoidably leads to the production of pairs of mesons: $D_i D_j$ (each containing $c$ quarks) or $\bar D_i \bar D_j$ (each containing $\bar c$ antiquarks). We calculate corresponding production rates for different combinations of charmed mesons as well as some differential distribution for $(D^0 D^0$ + $\bar D^0 \bar D^0)$ production. Within large theoretical uncertainties the predicted DPS cross section is fairly similar to the cross section measured recently by the LHCb collaboration. The best description is obtained with the Kimber-Martin-Ryskin (KMR) unintegrated gluon distribution, which very well simulates higher-order corrections. The contribution of SPS, calculated in the high-energy approximation, turned out to be rather small. Finally, we emphasize significant contribution of DPS mechanism to inclusive charmed meson spectra measured recently by ALICE, ATLAS and LHCb.
hep-ph/9912458
Greg Mahlon
Gregory Mahlon and Stephen Parke
Single Top Quark Production at the LHC: Understanding Spin
12 pages with 3 figures
Phys.Lett. B476 (2000) 323-330
10.1016/S0370-2693(00)00149-0
Fermilab-Pub-99/361-T, McGill/99-39, SLAC-PUB-8317
hep-ph hep-ex
null
We show that the single top quarks produced in the Wg-fusion channel at a proton-proton collider at a center-of-mass energy sqrt{s}=14 TeV posses a high degree of polarization in terms of a spin basis which decomposes the top quark spin in its rest frame along the direction of the spectator jet. A second useful spin basis is the eta-beamline basis, which decomposes the top quark spin along one of the two beam directions, depending on which hemisphere contains the spectator jet. We elucidate the interplay between the two- and three-body final states contributing to this production cross section in the context of determining the spin decomposition of the top quarks, and argue that the zero momentum frame helicity is undefined. We show that the usefulness of the spectator and eta-beamline spin bases is not adversely affected by the cuts required to separate the Wg-fusion signal from the background.
[ { "created": "Wed, 22 Dec 1999 20:31:58 GMT", "version": "v1" } ]
2009-10-31
[ [ "Mahlon", "Gregory", "" ], [ "Parke", "Stephen", "" ] ]
We show that the single top quarks produced in the Wg-fusion channel at a proton-proton collider at a center-of-mass energy sqrt{s}=14 TeV posses a high degree of polarization in terms of a spin basis which decomposes the top quark spin in its rest frame along the direction of the spectator jet. A second useful spin basis is the eta-beamline basis, which decomposes the top quark spin along one of the two beam directions, depending on which hemisphere contains the spectator jet. We elucidate the interplay between the two- and three-body final states contributing to this production cross section in the context of determining the spin decomposition of the top quarks, and argue that the zero momentum frame helicity is undefined. We show that the usefulness of the spectator and eta-beamline spin bases is not adversely affected by the cuts required to separate the Wg-fusion signal from the background.
hep-ph/0212346
Dieter Mueller
B. Melic, D. M\"uller, and K. Passek-Kumericki
Next-to-next-to-leading order prediction for the photon-to-pion transition form factor
62 pages LaTeX, 2 figures, 9 tables; typos corrected, some references added, to appear in Phys. Rev. D
Phys.Rev. D68 (2003) 014013
10.1103/PhysRevD.68.014013
null
hep-ph
null
We evaluate the next-to-next-to-leading order corrections to the hard-scattering amplitude of the photon-to-pion transition form factor. Our approach is based on the predictive power of the conformal operator product expansion, which is valid for a vanishing $\beta$-function in the so-called conformal scheme. The Wilson--coefficients appearing in the non-forward kinematics are then entirely determined from those of the polarized deep-inelastic scattering known to next-to-next-to-leading accuracy. We propose different schemes to include explicitly also the conformal symmetry breaking term proportional to the $\beta$-function, and discuss numerical predictions calculated in different kinematical regions. It is demonstrated that the photon-to-pion transition form factor can provide a fundamental testing ground for our QCD understanding of exclusive reactions.
[ { "created": "Mon, 23 Dec 2002 19:07:52 GMT", "version": "v1" }, { "created": "Wed, 18 Jun 2003 13:24:10 GMT", "version": "v2" } ]
2009-11-07
[ [ "Melic", "B.", "" ], [ "Müller", "D.", "" ], [ "Passek-Kumericki", "K.", "" ] ]
We evaluate the next-to-next-to-leading order corrections to the hard-scattering amplitude of the photon-to-pion transition form factor. Our approach is based on the predictive power of the conformal operator product expansion, which is valid for a vanishing $\beta$-function in the so-called conformal scheme. The Wilson--coefficients appearing in the non-forward kinematics are then entirely determined from those of the polarized deep-inelastic scattering known to next-to-next-to-leading accuracy. We propose different schemes to include explicitly also the conformal symmetry breaking term proportional to the $\beta$-function, and discuss numerical predictions calculated in different kinematical regions. It is demonstrated that the photon-to-pion transition form factor can provide a fundamental testing ground for our QCD understanding of exclusive reactions.
1212.0854
Sven Krippendorf
Marcin Badziak, Sven Krippendorf, Hans Peter Nilles, Martin Wolfgang Winkler
The heterotic MiniLandscape and the 126 GeV Higgs boson
22 pages, 3 figures
null
10.1007/JHEP03(2013)094
null
hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The MSSM candidates arising from the heterotic MiniLandscape feature a very constrained supersymmetry breaking pattern. This includes a fully predictable gaugino mass pattern, which is compressed compared to the CMSSM, and an inverted sfermion hierarchy due to distinct geometric localisation, featuring stops as light as 1 TeV. The observed Higgs mass sets a lower bound m_{gluino} > 1.2 TeV on the gluino mass. The electroweak fine-tuning is reduced by a UV relation between the scalar mass of the two heavy families and the gluino mass. While large parts of the favoured parameter space escape detection at the LHC, the prospects to test the MiniLandscape models with future dark matter searches are very promising.
[ { "created": "Tue, 4 Dec 2012 21:00:00 GMT", "version": "v1" } ]
2015-06-12
[ [ "Badziak", "Marcin", "" ], [ "Krippendorf", "Sven", "" ], [ "Nilles", "Hans Peter", "" ], [ "Winkler", "Martin Wolfgang", "" ] ]
The MSSM candidates arising from the heterotic MiniLandscape feature a very constrained supersymmetry breaking pattern. This includes a fully predictable gaugino mass pattern, which is compressed compared to the CMSSM, and an inverted sfermion hierarchy due to distinct geometric localisation, featuring stops as light as 1 TeV. The observed Higgs mass sets a lower bound m_{gluino} > 1.2 TeV on the gluino mass. The electroweak fine-tuning is reduced by a UV relation between the scalar mass of the two heavy families and the gluino mass. While large parts of the favoured parameter space escape detection at the LHC, the prospects to test the MiniLandscape models with future dark matter searches are very promising.
2310.07532
Subhadeep Sarkar
Arghya Choudhury, Arpita Mondal, Subhadeep Mondal, Subhadeep Sarkar
Slepton searches in the trilinear RPV SUSY scenarios at the HL-LHC and HE-LHC
15 pages, 7 figures, 5 Tables
null
10.1140/epjs/s11734-024-01102-9
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this work we have studied a multi-lepton final state arising from sneutrino and left-handed slepton production at the high luminosity and high energy LHC in the context of R-parity violating supersymmetry when only the lepton number violating $\lambda_{121}$ and/or $\lambda_{122}$ couplings are non-zero. We have taken into account both pair production and associated production of the three generations of left-handed sleptons and sneutrinos, which are assumed to be mass degenerate. The lightest supersymmetric particle is assumed to be bino and it decays via the R-parity violating couplings into light leptons and neutrinos. Our final state has a large lepton multiplicity, $N_{l}\geq 4~(l=e,~\mu)$. We perform both cut-based and machine learning based analyses for comparison. We present our results in the bino-slepton/sneutrino mass plane in terms of exclusion and discovery reach at the LHC. Following our analysis, the slepton mass can be discovered upto $\sim$ 1.54 TeV and excluded upto $\sim$ 1.87 TeV at the high luminosity LHC while these ranges go upto $\sim$ 2.46 TeV and $\sim$ 3.06 TeV respectively at the high energy LHC.
[ { "created": "Wed, 11 Oct 2023 14:36:28 GMT", "version": "v1" } ]
2024-02-16
[ [ "Choudhury", "Arghya", "" ], [ "Mondal", "Arpita", "" ], [ "Mondal", "Subhadeep", "" ], [ "Sarkar", "Subhadeep", "" ] ]
In this work we have studied a multi-lepton final state arising from sneutrino and left-handed slepton production at the high luminosity and high energy LHC in the context of R-parity violating supersymmetry when only the lepton number violating $\lambda_{121}$ and/or $\lambda_{122}$ couplings are non-zero. We have taken into account both pair production and associated production of the three generations of left-handed sleptons and sneutrinos, which are assumed to be mass degenerate. The lightest supersymmetric particle is assumed to be bino and it decays via the R-parity violating couplings into light leptons and neutrinos. Our final state has a large lepton multiplicity, $N_{l}\geq 4~(l=e,~\mu)$. We perform both cut-based and machine learning based analyses for comparison. We present our results in the bino-slepton/sneutrino mass plane in terms of exclusion and discovery reach at the LHC. Following our analysis, the slepton mass can be discovered upto $\sim$ 1.54 TeV and excluded upto $\sim$ 1.87 TeV at the high luminosity LHC while these ranges go upto $\sim$ 2.46 TeV and $\sim$ 3.06 TeV respectively at the high energy LHC.
0908.4180
Cyrille Marquet
C. Marquet and B. Wu
Exclusive vs. diffractive vector meson production in DIS at small x or off nuclei
5 pages, 1 figure, Proceedings of the XVIIth International Workshop on Deep Inelastic Scattering (DIS09), Madrid, Spain, April 26-30 2009
null
null
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The diffractive production of vector mesons in deep inelastic scattering (DIS) is calculated in the McLerran-Venugopalan model. This is relevant when large parton densities are probed by the virtual photon, as is the case at small Bjorken x or in DIS off nuclei. We investigate differences between the exclusive production (when the target doesn't break up) which dominates at small momentum transfer squared |t|, and the diffractive production (when the target scatters inelastically) which dominates at large |t|.
[ { "created": "Fri, 28 Aug 2009 10:22:55 GMT", "version": "v1" } ]
2009-08-31
[ [ "Marquet", "C.", "" ], [ "Wu", "B.", "" ] ]
The diffractive production of vector mesons in deep inelastic scattering (DIS) is calculated in the McLerran-Venugopalan model. This is relevant when large parton densities are probed by the virtual photon, as is the case at small Bjorken x or in DIS off nuclei. We investigate differences between the exclusive production (when the target doesn't break up) which dominates at small momentum transfer squared |t|, and the diffractive production (when the target scatters inelastically) which dominates at large |t|.
1504.04621
Andreas Papaefstathiou
Andreas Papaefstathiou
Discovering Higgs boson pair production through rare final states at a 100 TeV collider
9 pages, 2 figures, 7 tables. Matches published version
Phys. Rev. D 91, 113016 (2015)
10.1103/PhysRevD.91.113016
null
hep-ph hep-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider Higgs boson pair production at a future proton collider with centre-of-mass energy of 100 TeV, focusing on rare final states that include a bottom-anti-bottom quark pair and multiple isolated leptons: $hh \rightarrow (b\bar{b}) + n \ell + X$, $n = \{2,4\}$, $X = \{ E_T^\mathrm{miss}, \gamma, -\}$. We construct experimental search strategies for observing the process through these channels and make suggestions on the desired requirements for the detector design of the future collider.
[ { "created": "Fri, 17 Apr 2015 20:00:29 GMT", "version": "v1" }, { "created": "Mon, 4 May 2015 16:55:08 GMT", "version": "v2" }, { "created": "Tue, 3 Nov 2015 07:53:33 GMT", "version": "v3" } ]
2015-11-04
[ [ "Papaefstathiou", "Andreas", "" ] ]
We consider Higgs boson pair production at a future proton collider with centre-of-mass energy of 100 TeV, focusing on rare final states that include a bottom-anti-bottom quark pair and multiple isolated leptons: $hh \rightarrow (b\bar{b}) + n \ell + X$, $n = \{2,4\}$, $X = \{ E_T^\mathrm{miss}, \gamma, -\}$. We construct experimental search strategies for observing the process through these channels and make suggestions on the desired requirements for the detector design of the future collider.
hep-ph/9906368
Joaquim Inacio da Silva Marcos
G.C. Branco, M.N. Rebelo and J.I. Silva-Marcos
Large Neutrino Mixing with Universal Strength of Yukawa Couplings
7 pages, ReVTeX, small comments added
Phys.Rev. D62 (2000) 073004
10.1103/PhysRevD.62.073004
null
hep-ph
null
We analyse, within the framework of universal strength for Yukawa couplings (USY), various structures for the Dirac and Majorana neutrino mass matrices giving rise, through the see-saw mechanism, to a degenerate mass spectrum. A specific USY ansatz is presented for the charged lepton and neutrino effective mass matrix, leading to quasi-degenerate neutrinos and a leptonic mixing matrix which provides a large angle solution for both the atmospheric and solar neutrino problems.
[ { "created": "Tue, 15 Jun 1999 11:26:35 GMT", "version": "v1" }, { "created": "Thu, 14 Oct 1999 13:34:55 GMT", "version": "v2" }, { "created": "Tue, 8 Feb 2000 14:31:08 GMT", "version": "v3" } ]
2009-10-31
[ [ "Branco", "G. C.", "" ], [ "Rebelo", "M. N.", "" ], [ "Silva-Marcos", "J. I.", "" ] ]
We analyse, within the framework of universal strength for Yukawa couplings (USY), various structures for the Dirac and Majorana neutrino mass matrices giving rise, through the see-saw mechanism, to a degenerate mass spectrum. A specific USY ansatz is presented for the charged lepton and neutrino effective mass matrix, leading to quasi-degenerate neutrinos and a leptonic mixing matrix which provides a large angle solution for both the atmospheric and solar neutrino problems.
1008.4987
Linxia Lu
Lin-Xia L\"u, Zhen-Jun Xiao, Shuai-Wei Wang and Wen-Jun Li
The double charm decays of B Mesons in the mSUGRA model
15 pages, 5tables, no figures
Commun.Theor.Phys.56:125-133,2011
10.1088/0253-6102/56/1/22
null
hep-ph
http://creativecommons.org/licenses/by/3.0/
Based on the low energy effective Hamiltonian with naive factorization, we calculate the branching ratios(BRs) and CP asymmetries (CPAs) for the twenty three double charm decays $B/B_s \to D^{(*)}_{(s)} D^{(*)}_{(s)}$ in both the standard model (SM) and the minimal supergravity (mSUGRA) model. Within the considered parameter space, we find that (a) the theoretical predictions for the BRs, CPAs and the polarization fractions in the SM and the mSUGRA model are all consistent with the currently available data within $\pm 2\sigma$ errors; (b) For all the considered decays, the supersymmetric contributions in the mSUGRA model are very small, less than $7\%$ numerically. It may be difficult to observe so small SUSY contributions even at LHC.
[ { "created": "Mon, 30 Aug 2010 02:40:28 GMT", "version": "v1" } ]
2011-08-04
[ [ "Lü", "Lin-Xia", "" ], [ "Xiao", "Zhen-Jun", "" ], [ "Wang", "Shuai-Wei", "" ], [ "Li", "Wen-Jun", "" ] ]
Based on the low energy effective Hamiltonian with naive factorization, we calculate the branching ratios(BRs) and CP asymmetries (CPAs) for the twenty three double charm decays $B/B_s \to D^{(*)}_{(s)} D^{(*)}_{(s)}$ in both the standard model (SM) and the minimal supergravity (mSUGRA) model. Within the considered parameter space, we find that (a) the theoretical predictions for the BRs, CPAs and the polarization fractions in the SM and the mSUGRA model are all consistent with the currently available data within $\pm 2\sigma$ errors; (b) For all the considered decays, the supersymmetric contributions in the mSUGRA model are very small, less than $7\%$ numerically. It may be difficult to observe so small SUSY contributions even at LHC.
2202.07830
Jason Evans
Jason L. Evans and Keith A. Olive
Higgsino Dark Matter in Pure Gravity Mediated Supersymmetry
20 pages, 18 figures
null
10.1103/PhysRevD.106.055026
UMN-TH-4114/22, FTPI-MINN-22/05
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider the prospects for the direct detection of dark matter in pure gravity meditation (PGM) models of supersymmetry breaking. Minimal PGM models require only two parameters, the gravitino mass, $m_{3/2}$, which sets the UV mass for all scalar masses, and $\tan\beta$. Gaugino masses are generated through anomaly mediation. Typically the lightest supersymmetric state (the dark matter candidate) is a wino. Here, we consider a one-parameter extension of the minimal model by allowing the Higgs soft masses to deviate from universality. For simplicity, we take these to be equal and use the $\mu$-term as a surrogate. We also consider non-universal stop masses. When $|\mu| \sim 1$ TeV, the Higgsino is a viable dark matter candidate when the gravitino mass is of order $\sim 1$ PeV and $\tan\beta \simeq 2$. We calculate the spin-dependent and spin-independent cross sections for dark matter scattering on protons. For spin-independent scattering, existing experimental limits place constraints on the PGM parameter space. Much of the currently allowed parameter space lies above the irreducible neutrino background. Thus, future direct detection experiments will be able to probe much of the remaining PGM parameter space.
[ { "created": "Wed, 16 Feb 2022 02:27:56 GMT", "version": "v1" } ]
2022-10-05
[ [ "Evans", "Jason L.", "" ], [ "Olive", "Keith A.", "" ] ]
We consider the prospects for the direct detection of dark matter in pure gravity meditation (PGM) models of supersymmetry breaking. Minimal PGM models require only two parameters, the gravitino mass, $m_{3/2}$, which sets the UV mass for all scalar masses, and $\tan\beta$. Gaugino masses are generated through anomaly mediation. Typically the lightest supersymmetric state (the dark matter candidate) is a wino. Here, we consider a one-parameter extension of the minimal model by allowing the Higgs soft masses to deviate from universality. For simplicity, we take these to be equal and use the $\mu$-term as a surrogate. We also consider non-universal stop masses. When $|\mu| \sim 1$ TeV, the Higgsino is a viable dark matter candidate when the gravitino mass is of order $\sim 1$ PeV and $\tan\beta \simeq 2$. We calculate the spin-dependent and spin-independent cross sections for dark matter scattering on protons. For spin-independent scattering, existing experimental limits place constraints on the PGM parameter space. Much of the currently allowed parameter space lies above the irreducible neutrino background. Thus, future direct detection experiments will be able to probe much of the remaining PGM parameter space.
2309.00374
Miguel Guti\'errez
Pablo de la Torre, Miguel Guti\'errez, Manuel Masip
Monochromatic neutrinos from dark matter through the Higgs portal
18 pages
null
null
null
hep-ph astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We define a minimal model of dark matter with a fermion singlet $\chi$ coupled to the visible sector through the Higgs portal and with a heavy Dirac neutrino $N$ that opens the annihilation channel $\chi \chi \to N \nu$. The model provides the observed relic abundance consistently with bounds from direct searches and implies a monochromatic neutrino signal at 10 GeV-1 TeV in indirect searches. In particular, we obtain the capture rate of $\chi$ by the Sun and show that the signal could be above the "neutrino floor" produced by cosmic rays showering in the solar surface. In most benchmark models this solar astrophysical background is above the expected dark matter signal, so the model that we propose is a canonical example of WIMP not excluded by direct searches that could be studied at neutrino telescopes and also at colliders.
[ { "created": "Fri, 1 Sep 2023 10:19:19 GMT", "version": "v1" } ]
2023-09-04
[ [ "de la Torre", "Pablo", "" ], [ "Gutiérrez", "Miguel", "" ], [ "Masip", "Manuel", "" ] ]
We define a minimal model of dark matter with a fermion singlet $\chi$ coupled to the visible sector through the Higgs portal and with a heavy Dirac neutrino $N$ that opens the annihilation channel $\chi \chi \to N \nu$. The model provides the observed relic abundance consistently with bounds from direct searches and implies a monochromatic neutrino signal at 10 GeV-1 TeV in indirect searches. In particular, we obtain the capture rate of $\chi$ by the Sun and show that the signal could be above the "neutrino floor" produced by cosmic rays showering in the solar surface. In most benchmark models this solar astrophysical background is above the expected dark matter signal, so the model that we propose is a canonical example of WIMP not excluded by direct searches that could be studied at neutrino telescopes and also at colliders.
hep-ph/0002073
Chung Ngoc Leung
C.N. Leung (U. of Delaware)
Neutrino Tests of General and Special Relativity
replaced incorrect abstract in earlier version; LaTeX, 10 pages; 1 postscript figure included at the end; to appear in the Proceedings of the 1999 Workshop on Neutrino Factories Based on a Muon Collider, Lyon, France, July 5-9, 1999
Nucl.Instrum.Meth.A451:81-85,2000
10.1016/S0168-9002(00)00376-4
null
hep-ph
null
We review the status of testing the principle of equivalence and Lorentz invariance from atmospheric and solar neutrino experiments.
[ { "created": "Mon, 7 Feb 2000 16:57:34 GMT", "version": "v1" }, { "created": "Tue, 8 Feb 2000 16:21:43 GMT", "version": "v2" } ]
2008-11-26
[ [ "Leung", "C. N.", "", "U. of Delaware" ] ]
We review the status of testing the principle of equivalence and Lorentz invariance from atmospheric and solar neutrino experiments.
1207.0014
Fredy Ochoa
C. Alvarado, R. Martinez, F. Ochoa
Quark mass hierarchy in 3-3-1 models
null
Phys. Rev. D86, 025027 (2012)
10.1103/PhysRevD.86.025027
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the mass spectrum of the quark sector in an special type I-like model with gauge symmetry $SU(3)_c \otimes SU(3)_L \otimes U(1)_X$. By considering couplings with scalar triplets at large ($\sim TeV$) and small ($\sim GeV$) scales, we obtain specific zero-texture mass matrices for the quarks which predict three massless quarks ($u,d,s$) and three massive quarks ($c,b,t$) at the electroweak scale ($\sim$ GeV). Taking into account mixing couplings with three heavy quarks at large scales predicted by the model, the three massless quarks obtain masses at small order that depends on the inverse of the large scale. Thus, masses of the form $m_u \lesssim m_d < m_s \sim MeV$ and $ m_{c,b,t} \sim GeV$ can be obtained naturally from the gauge structure of the model.
[ { "created": "Fri, 29 Jun 2012 20:27:36 GMT", "version": "v1" } ]
2012-07-27
[ [ "Alvarado", "C.", "" ], [ "Martinez", "R.", "" ], [ "Ochoa", "F.", "" ] ]
We study the mass spectrum of the quark sector in an special type I-like model with gauge symmetry $SU(3)_c \otimes SU(3)_L \otimes U(1)_X$. By considering couplings with scalar triplets at large ($\sim TeV$) and small ($\sim GeV$) scales, we obtain specific zero-texture mass matrices for the quarks which predict three massless quarks ($u,d,s$) and three massive quarks ($c,b,t$) at the electroweak scale ($\sim$ GeV). Taking into account mixing couplings with three heavy quarks at large scales predicted by the model, the three massless quarks obtain masses at small order that depends on the inverse of the large scale. Thus, masses of the form $m_u \lesssim m_d < m_s \sim MeV$ and $ m_{c,b,t} \sim GeV$ can be obtained naturally from the gauge structure of the model.
hep-ph/9809556
K. Matsuda
H.Nishiura, K.Matsuda, T.Fukuyama
Constraints of Mixing Angles from Lepton Number Violating Processes
15pp, LaTeX, 5 Figures
Mod.Phys.Lett. A14 (1999) 433-446
10.1142/S0217732399000493
null
hep-ph
null
We discuss the constraints of lepton mixing angles from lepton number violating processes such as neutrinoless double beta decay, (\mu^-)-(e^+) conversion and K decay, $K^- \to \pi^+\mu^-\mu^-$ which are allowed only if neutrinos are Majorana particles. The rates of these processes are proportional to the averaged neutrino mass defined by $<m_{\nu} >_{a b}\equiv |\sum_{j=1}^{3}U_{a j} U_{b j}m_j|$ in the absence of right-handed weak coupling. Here $a, b (j)$ are flavour(mass) eigen states and $U_{a j}$ is the left-handed lepton mixing matrix. We obtain the consistency conditions which are satisfied irrelevant to the concrete values of CP violation phases (three phases in Majorana neutrinos). These conditions constrain the lepton mixing angles, neutrino masses $m_i$ and (< m_{\nu} >_{a b}). By using these constraints we obtain the limits on the averaged neutrino masses for (\mu^-)-(e^+) conversion and K decay, $K^- \to \pi^+\mu^-\mu^-$.
[ { "created": "Mon, 28 Sep 1998 04:53:19 GMT", "version": "v1" } ]
2009-10-31
[ [ "Nishiura", "H.", "" ], [ "Matsuda", "K.", "" ], [ "Fukuyama", "T.", "" ] ]
We discuss the constraints of lepton mixing angles from lepton number violating processes such as neutrinoless double beta decay, (\mu^-)-(e^+) conversion and K decay, $K^- \to \pi^+\mu^-\mu^-$ which are allowed only if neutrinos are Majorana particles. The rates of these processes are proportional to the averaged neutrino mass defined by $<m_{\nu} >_{a b}\equiv |\sum_{j=1}^{3}U_{a j} U_{b j}m_j|$ in the absence of right-handed weak coupling. Here $a, b (j)$ are flavour(mass) eigen states and $U_{a j}$ is the left-handed lepton mixing matrix. We obtain the consistency conditions which are satisfied irrelevant to the concrete values of CP violation phases (three phases in Majorana neutrinos). These conditions constrain the lepton mixing angles, neutrino masses $m_i$ and (< m_{\nu} >_{a b}). By using these constraints we obtain the limits on the averaged neutrino masses for (\mu^-)-(e^+) conversion and K decay, $K^- \to \pi^+\mu^-\mu^-$.
hep-ph/0510065
Douglas Spolyar
Katherine Freese, James T. Liu and Douglas Spolyar
Devaluation: a dynamical mechanism for a naturally small cosmological constant
6 pages and prepared in ReV-TeX added notes on eltro-weak breaking and ds vacua
Phys.Lett. B634 (2006) 119-124
10.1016/j.physletb.2006.01.002
MCTP-05-94
hep-ph astro-ph hep-th
null
We propose a natural solution to the cosmological constant problem consistent with the standard cosmology and successful over a broad range of energies. This solution is based on the existence of a new field, the devaluton, with its potential modeled on a tilted cosine. After inflation, the universe reheats and populates the devaluton's many minima. As the universe cools, domain walls form between different regions. The domain wall network then evolves and sweeps away regions of higher vacuum energy in favor of lower energy ones. Gravitation itself provides a cutoff at a minimum vacuum energy, thus leaving the universe with a small cosmological constant comparable in magnitude to the present day dark energy density.
[ { "created": "Wed, 5 Oct 2005 19:29:10 GMT", "version": "v1" }, { "created": "Wed, 26 Oct 2005 17:59:01 GMT", "version": "v2" } ]
2009-11-11
[ [ "Freese", "Katherine", "" ], [ "Liu", "James T.", "" ], [ "Spolyar", "Douglas", "" ] ]
We propose a natural solution to the cosmological constant problem consistent with the standard cosmology and successful over a broad range of energies. This solution is based on the existence of a new field, the devaluton, with its potential modeled on a tilted cosine. After inflation, the universe reheats and populates the devaluton's many minima. As the universe cools, domain walls form between different regions. The domain wall network then evolves and sweeps away regions of higher vacuum energy in favor of lower energy ones. Gravitation itself provides a cutoff at a minimum vacuum energy, thus leaving the universe with a small cosmological constant comparable in magnitude to the present day dark energy density.
2401.12013
Jose Manuel Morgado Ch\'avez
P. Dall'Olio, F. De Soto, C. Mezrag, J.M. Morgado Ch\'avez, H. Moutarde, J. Rodr\'iguez-Quintero, P. Sznajder and J. Segovia
Unraveling Generalized Parton Distributions Through Lorentz Symmetry and Partial DGLAP Knowledge
20 pages, 10 figures
null
null
null
hep-ph nucl-th
http://creativecommons.org/licenses/by/4.0/
Relying on the polynomiality property of generalized parton distributions, which roots on Lorentz covariance, we prove that it is enough to know them at vanishing- and low-skewness within the DGLAP region to obtain a unique extension to their entire support up to a D-term. We put this idea in practice using two methods: Reconstruction using artificial neural networks and finite-elements methods. We benchmark our results against standard models for generalized parton distributions. In agreement with the formal expectation, we obtain a very accurate reconstructions for a maximal value of the skewness as low as 20% of the longitudinal momentum fraction. This result might be relevant for reconstruction of generalized parton distribution from experimental and lattice QCD data, where computations are for now, restricted in skewness.
[ { "created": "Mon, 22 Jan 2024 14:59:11 GMT", "version": "v1" }, { "created": "Mon, 25 Mar 2024 08:37:21 GMT", "version": "v2" } ]
2024-03-26
[ [ "Dall'Olio", "P.", "" ], [ "De Soto", "F.", "" ], [ "Mezrag", "C.", "" ], [ "Chávez", "J. M. Morgado", "" ], [ "Moutarde", "H.", "" ], [ "Rodríguez-Quintero", "J.", "" ], [ "Sznajder", "P.", "" ], [ ...
Relying on the polynomiality property of generalized parton distributions, which roots on Lorentz covariance, we prove that it is enough to know them at vanishing- and low-skewness within the DGLAP region to obtain a unique extension to their entire support up to a D-term. We put this idea in practice using two methods: Reconstruction using artificial neural networks and finite-elements methods. We benchmark our results against standard models for generalized parton distributions. In agreement with the formal expectation, we obtain a very accurate reconstructions for a maximal value of the skewness as low as 20% of the longitudinal momentum fraction. This result might be relevant for reconstruction of generalized parton distribution from experimental and lattice QCD data, where computations are for now, restricted in skewness.