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|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1310.1082 | Ulrich Haisch | Rhorry Gauld, Florian Goertz and Ulrich Haisch | An explicit Z'-boson explanation of the B->K*mu+mu- anomaly | 20 pages, 5 figures; v2: Eqs. (9.2), (9.4) and (9.5) corrected, typos
fixed and references added; matches version published in JHEP | null | 10.1007/JHEP01(2014)069 | null | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | A global fit to the recent B->K*mu+mu- data shows indications for a large
new-physics contribution to the Wilson coefficient of the semi-leptonic vector
operator. In this article we consider a simple Z'-boson model of 3-3-1 type
that can accommodate such an effect without violating any other constraint from
quark-flavour physics. Implications for yet unobserved decay modes such as
B->Xsnunubar and longstanding puzzles like B->piK are also discussed. The
Z'-boson masses required to address the observed anomaly lie in the range of 7
TeV. Such heavy Z' bosons evade the existing bounds from precision data and
direct searches, and will remain difficult to discover even at a
high-luminosity LHC. The potential of an ILC as well as the next generation of
low-energy parity-violation experiments in constraining the Z'-boson parameter
space is also examined.
| [
{
"created": "Thu, 3 Oct 2013 20:00:01 GMT",
"version": "v1"
},
{
"created": "Tue, 14 Jan 2014 08:03:20 GMT",
"version": "v2"
}
] | 2015-06-17 | [
[
"Gauld",
"Rhorry",
""
],
[
"Goertz",
"Florian",
""
],
[
"Haisch",
"Ulrich",
""
]
] | A global fit to the recent B->K*mu+mu- data shows indications for a large new-physics contribution to the Wilson coefficient of the semi-leptonic vector operator. In this article we consider a simple Z'-boson model of 3-3-1 type that can accommodate such an effect without violating any other constraint from quark-flavour physics. Implications for yet unobserved decay modes such as B->Xsnunubar and longstanding puzzles like B->piK are also discussed. The Z'-boson masses required to address the observed anomaly lie in the range of 7 TeV. Such heavy Z' bosons evade the existing bounds from precision data and direct searches, and will remain difficult to discover even at a high-luminosity LHC. The potential of an ILC as well as the next generation of low-energy parity-violation experiments in constraining the Z'-boson parameter space is also examined. |
1108.2442 | Xing-Gang Wu | Xian-You Wang and Xing-Gang Wu | A Trick to Improve the Efficiency of Generating Unweighted $B_c$ Events
from BCVEGPY | 4 pages, 2 figures. To be published in Computer Physics
Communications | Comput.Phys.Commun. 183, 442-445 (2012) | 10.1016/j.cpc.2011.08.024 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In the present paper, we provide an addendum to improve the efficiency of
generating unweighted events within PYTHIA environment for the generator
BCVEGPY2.1 [C.H. Chang, J.X. Wang and X.G. Wu, Comput.Phys.Commun.{\bf 174},
241(2006)]. This trick is helpful for experimental simulation. Moreover, the
BCVEGPY output has also been improved, i.e. one Les Houches Event common block
has been added so as to generate a standard Les Houches Event file that
contains the information of the generated $B_c$ meson and the accompanying
partons, which can be more conveniently used for further simulation.
| [
{
"created": "Thu, 11 Aug 2011 16:13:13 GMT",
"version": "v1"
}
] | 2011-11-18 | [
[
"Wang",
"Xian-You",
""
],
[
"Wu",
"Xing-Gang",
""
]
] | In the present paper, we provide an addendum to improve the efficiency of generating unweighted events within PYTHIA environment for the generator BCVEGPY2.1 [C.H. Chang, J.X. Wang and X.G. Wu, Comput.Phys.Commun.{\bf 174}, 241(2006)]. This trick is helpful for experimental simulation. Moreover, the BCVEGPY output has also been improved, i.e. one Les Houches Event common block has been added so as to generate a standard Les Houches Event file that contains the information of the generated $B_c$ meson and the accompanying partons, which can be more conveniently used for further simulation. |
1910.09981 | Zhi-Gang Wang | Zhi-Gang Wang | Two-particle contributions and nonlocal effects in the QCD sum rules for
the axialvector tetraquark candidate $Z_c(3900)$ | 23 pages, 24 figures | Int. J. Mod. Phys. A35 (2020) 2050138 | 10.1142/S0217751X20501389 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this article, we study the $Z_c(3900)$ with the QCD sum rules in details
by including the two-particle scattering state contributions and nonlocal
effects between the diquark and antidiquark constituents. The two-particle
scattering state contributions cannot saturate the QCD sum rules at the hadron
side, the contribution of the $Z_c(3900)$ plays an un-substitutable role, we
can saturate the QCD sum rules with or without the two-particle scattering
state contributions. If there exists a barrier or spatial separation between
the diquark and antidiquark constituents, the Feynman diagrams can be divided
into the factorizable and nonfactorizable diagrams. The factorizable diagrams
consist of two colored clusters and lead to a stable tetraquark state. The
nonfactorizable Feynman diagrams correspond to the tunnelling effects, which
play a minor important role in the QCD sum rules, and are consistent with the
small width of the $Z_c(3900)$. It is feasible to apply the QCD sum rules to
study the tetraquark states, which begin to receive contributions at the order
$\mathcal{O}(\alpha_s^0)$, not at the order $\mathcal{O}(\alpha_s^2)$.
| [
{
"created": "Tue, 22 Oct 2019 13:49:27 GMT",
"version": "v1"
},
{
"created": "Wed, 25 Dec 2019 01:45:28 GMT",
"version": "v2"
},
{
"created": "Sat, 22 Feb 2020 07:48:22 GMT",
"version": "v3"
},
{
"created": "Tue, 16 Jun 2020 13:47:45 GMT",
"version": "v4"
},
{
"c... | 2020-09-03 | [
[
"Wang",
"Zhi-Gang",
""
]
] | In this article, we study the $Z_c(3900)$ with the QCD sum rules in details by including the two-particle scattering state contributions and nonlocal effects between the diquark and antidiquark constituents. The two-particle scattering state contributions cannot saturate the QCD sum rules at the hadron side, the contribution of the $Z_c(3900)$ plays an un-substitutable role, we can saturate the QCD sum rules with or without the two-particle scattering state contributions. If there exists a barrier or spatial separation between the diquark and antidiquark constituents, the Feynman diagrams can be divided into the factorizable and nonfactorizable diagrams. The factorizable diagrams consist of two colored clusters and lead to a stable tetraquark state. The nonfactorizable Feynman diagrams correspond to the tunnelling effects, which play a minor important role in the QCD sum rules, and are consistent with the small width of the $Z_c(3900)$. It is feasible to apply the QCD sum rules to study the tetraquark states, which begin to receive contributions at the order $\mathcal{O}(\alpha_s^0)$, not at the order $\mathcal{O}(\alpha_s^2)$. |
0910.2435 | Albert Villanova del Moral | M. Hirsch, T. Kernreiter, J. C. Romao, and Albert Villanova del Moral | Minimal Supersymmetric Inverse Seesaw: Neutrino masses, lepton flavour
violation and LHC phenomenology | 26 pages, 4 figures; added explanatory comments, final version for
publication | JHEP 1001:103,2010 | 10.1007/JHEP01(2010)103 | IFIC/09-48, CFTP/09-033 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study neutrino masses in the framework of the supersymmetric inverse
seesaw model. Different from the non-supersymmetric version a minimal
realization with just one pair of singlets is sufficient to explain all
neutrino data. We compute the neutrino mass matrix up to 1-loop order and show
how neutrino data can be described in terms of the model parameters. We then
calculate rates for lepton flavour violating (LFV) processes, such as $\mu \to
e \gamma$, and chargino decays to singlet scalar neutrinos. The latter decays
are potentially observable at the LHC and show a characteristic decay pattern
dictated by the same parameters which generate the observed large neutrino
angles.
| [
{
"created": "Tue, 13 Oct 2009 17:26:49 GMT",
"version": "v1"
},
{
"created": "Mon, 8 Feb 2010 13:23:44 GMT",
"version": "v2"
}
] | 2010-02-08 | [
[
"Hirsch",
"M.",
""
],
[
"Kernreiter",
"T.",
""
],
[
"Romao",
"J. C.",
""
],
[
"del Moral",
"Albert Villanova",
""
]
] | We study neutrino masses in the framework of the supersymmetric inverse seesaw model. Different from the non-supersymmetric version a minimal realization with just one pair of singlets is sufficient to explain all neutrino data. We compute the neutrino mass matrix up to 1-loop order and show how neutrino data can be described in terms of the model parameters. We then calculate rates for lepton flavour violating (LFV) processes, such as $\mu \to e \gamma$, and chargino decays to singlet scalar neutrinos. The latter decays are potentially observable at the LHC and show a characteristic decay pattern dictated by the same parameters which generate the observed large neutrino angles. |
2108.03828 | Claude Duhr | Claude Duhr, Vladimir A. Smirnov, Lorenzo Tancredi | Analytic results for two-loop planar master integrals for Bhabha
scattering | 28 pages, 3 figures | null | 10.1007/JHEP09(2021)120 | BONN-TH-2021-06, OUTP-21-19P | hep-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We analytically evaluate the master integrals for the second type of planar
contributions to the massive two-loop Bhabha scattering in QED using
differential equa- tions with canonical bases. We obtain results in terms of
multiple polylogarithms for all the master integrals but one, for which we
derive a compact result in terms of elliptic mul- tiple polylogarithms. As a
byproduct, we also provide a compact analytic result in terms of elliptic
multiple polylogarithms for an integral belonging to the first family of planar
Bhabha integrals, whose computation in terms of polylogarithms was addressed
previously in the literature.
| [
{
"created": "Mon, 9 Aug 2021 06:21:44 GMT",
"version": "v1"
}
] | 2021-10-04 | [
[
"Duhr",
"Claude",
""
],
[
"Smirnov",
"Vladimir A.",
""
],
[
"Tancredi",
"Lorenzo",
""
]
] | We analytically evaluate the master integrals for the second type of planar contributions to the massive two-loop Bhabha scattering in QED using differential equa- tions with canonical bases. We obtain results in terms of multiple polylogarithms for all the master integrals but one, for which we derive a compact result in terms of elliptic mul- tiple polylogarithms. As a byproduct, we also provide a compact analytic result in terms of elliptic multiple polylogarithms for an integral belonging to the first family of planar Bhabha integrals, whose computation in terms of polylogarithms was addressed previously in the literature. |
hep-ph/9705301 | null | J.R. Pelaez (Dept. Fisica Teorica, Univ. Complutense. Madrid. Spain) | Strong WW scattering and resonances at LHC | 5 pages, Latex, uses epsf, one eps figure. Contribution to the 32nd
Rencontres de Moriond ``Electroweak Interactions and Unified Theories'' | null | null | FT/UCM-3/97 | hep-ph | null | The low energy dynamics of the general strongly interacting symmetry breaking
sector can be easily described using effective chiral Lagrangians. Indeed, the
enhancement in WW scattering at LHC, that would imply the existence of such an
strong interaction, can be described with just two chiral parameters. These
techniques have been shown to reproduce remarkably well the low-energy
pion-pion scattering data, which follows a similar formalism. In this work we
first review the LHC sensitivity to those two chiral parameters (in the hardest
case of non-resonant low-energy WW scattering). Later it is shown how we can
predict the general resonance spectrum of the strongly interacting symmetry
breaking sector. For that purpose, we use the inverse amplitude method which is
also very successful reproducing the lightest hadronic resonances from data in
the low-energy non resonant region. We thus present an study of the regions in
parameter space where one, two or no resonances may appear.
| [
{
"created": "Tue, 13 May 1997 11:49:38 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Pelaez",
"J. R.",
"",
"Dept. Fisica Teorica, Univ. Complutense. Madrid. Spain"
]
] | The low energy dynamics of the general strongly interacting symmetry breaking sector can be easily described using effective chiral Lagrangians. Indeed, the enhancement in WW scattering at LHC, that would imply the existence of such an strong interaction, can be described with just two chiral parameters. These techniques have been shown to reproduce remarkably well the low-energy pion-pion scattering data, which follows a similar formalism. In this work we first review the LHC sensitivity to those two chiral parameters (in the hardest case of non-resonant low-energy WW scattering). Later it is shown how we can predict the general resonance spectrum of the strongly interacting symmetry breaking sector. For that purpose, we use the inverse amplitude method which is also very successful reproducing the lightest hadronic resonances from data in the low-energy non resonant region. We thus present an study of the regions in parameter space where one, two or no resonances may appear. |
0805.3993 | Zvi Bern | Z. Bern, J. J. M. Carrasco and H. Johansson | New Relations for Gauge-Theory Amplitudes | 40 pages, 7 figures, RevTex, v2 minor corrections | Phys.Rev.D78:085011,2008 | 10.1103/PhysRevD.78.085011 | UCLA/07/TEP/15 | hep-ph gr-qc hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present an identity satisfied by the kinematic factors of diagrams
describing the tree amplitudes of massless gauge theories. This identity is a
kinematic analog of the Jacobi identity for color factors. Using this we find
new relations between color-ordered partial amplitudes. We discuss applications
to multi-loop calculations via the unitarity method. In particular, we
illustrate the relations between different contributions to a two-loop
four-point QCD amplitude. We also use this identity to reorganize gravity tree
amplitudes diagram by diagram, offering new insight into the structure of the
KLT relations between gauge and gravity tree amplitudes. This can be used to
obtain novel relations similar to the KLT ones. We expect this to be helpful in
higher-loop studies of the ultraviolet properties of gravity theories.
| [
{
"created": "Mon, 26 May 2008 18:56:06 GMT",
"version": "v1"
},
{
"created": "Fri, 10 Oct 2008 23:08:40 GMT",
"version": "v2"
}
] | 2008-11-26 | [
[
"Bern",
"Z.",
""
],
[
"Carrasco",
"J. J. M.",
""
],
[
"Johansson",
"H.",
""
]
] | We present an identity satisfied by the kinematic factors of diagrams describing the tree amplitudes of massless gauge theories. This identity is a kinematic analog of the Jacobi identity for color factors. Using this we find new relations between color-ordered partial amplitudes. We discuss applications to multi-loop calculations via the unitarity method. In particular, we illustrate the relations between different contributions to a two-loop four-point QCD amplitude. We also use this identity to reorganize gravity tree amplitudes diagram by diagram, offering new insight into the structure of the KLT relations between gauge and gravity tree amplitudes. This can be used to obtain novel relations similar to the KLT ones. We expect this to be helpful in higher-loop studies of the ultraviolet properties of gravity theories. |
hep-ph/0412127 | Hee-Jung Lee | Hee-Jung Lee, N.I. Kochelev, and V. Vento | Triquark correlations and pentaquarks in a QCD sum rule approach | 11 pages, 9 figures, corrected typos, reference added, introduction
and conclusions modified slightly | Phys.Lett. B610 (2005) 50-60 | 10.1016/j.physletb.2005.01.081 | FTUV-04-1209, IFIC-04-70 | hep-ph hep-ex nucl-th | null | The role of quark correlations in the description of hadron dynamics in many
domains of physics, from low energy dynamics to very hot(dense) systems, is
being appreciated. Strong correlations of two quarks (diquark) have been widely
investigated in this respect. Recently, we have proposed a dynamical scheme to
describe the $\Theta^+$ pentaquark in which also three quark correlations
(triquark) were instrumental in producing a low mass exotic state. We perform a
study, within the QCD sum rule approach including OPE and direct instanton
contributions, of triquark correlations and obtain two quasi-bound light
$ud\bar{s}$ color quark clusters of 800 MeV and 930 MeV respectively.
| [
{
"created": "Thu, 9 Dec 2004 15:08:58 GMT",
"version": "v1"
},
{
"created": "Fri, 10 Dec 2004 14:20:36 GMT",
"version": "v2"
},
{
"created": "Thu, 16 Dec 2004 16:37:06 GMT",
"version": "v3"
},
{
"created": "Wed, 26 Jan 2005 09:11:38 GMT",
"version": "v4"
}
] | 2009-11-10 | [
[
"Lee",
"Hee-Jung",
""
],
[
"Kochelev",
"N. I.",
""
],
[
"Vento",
"V.",
""
]
] | The role of quark correlations in the description of hadron dynamics in many domains of physics, from low energy dynamics to very hot(dense) systems, is being appreciated. Strong correlations of two quarks (diquark) have been widely investigated in this respect. Recently, we have proposed a dynamical scheme to describe the $\Theta^+$ pentaquark in which also three quark correlations (triquark) were instrumental in producing a low mass exotic state. We perform a study, within the QCD sum rule approach including OPE and direct instanton contributions, of triquark correlations and obtain two quasi-bound light $ud\bar{s}$ color quark clusters of 800 MeV and 930 MeV respectively. |
hep-ph/0407056 | Aleksey I. Alekseev | A.I. Alekseev, B.A. Arbuzov | Beta-Function in QCD and Gluon Condensate | LaTeX, 10 pages, 2 figures, added reference, not great elucidation
after eq.(3) and in abstract | null | null | null | hep-ph | null | Under assumption of singular behavior of alpha_s(q^2) at q^2 sim 0 and of
large q^2 behavior, corresponding to the perturbation theory up to four loops,
a procedure is considered of matching the beta-function at a boundary of
perturbative and non-perturbative regions. The contribution of the
non-perturbative region to the gluon condensate is calculated with varying
normalization condition alpha_s(m_tau^2) = 0.29, 0.30,..., 0.36 for two
different ways of definition of the non-perturbative invariant charge in the
infrared region. We obtain quite consistent results for values of the gluon
condensate, nonperturbative region scale q_0, and the string tension sigma.
| [
{
"created": "Mon, 5 Jul 2004 15:42:33 GMT",
"version": "v1"
},
{
"created": "Fri, 27 Aug 2004 09:36:31 GMT",
"version": "v2"
}
] | 2007-05-23 | [
[
"Alekseev",
"A. I.",
""
],
[
"Arbuzov",
"B. A.",
""
]
] | Under assumption of singular behavior of alpha_s(q^2) at q^2 sim 0 and of large q^2 behavior, corresponding to the perturbation theory up to four loops, a procedure is considered of matching the beta-function at a boundary of perturbative and non-perturbative regions. The contribution of the non-perturbative region to the gluon condensate is calculated with varying normalization condition alpha_s(m_tau^2) = 0.29, 0.30,..., 0.36 for two different ways of definition of the non-perturbative invariant charge in the infrared region. We obtain quite consistent results for values of the gluon condensate, nonperturbative region scale q_0, and the string tension sigma. |
0909.3196 | Krzysztof Rolbiecki | Krzysztof Rolbiecki, Jamie Tattersall and Gudrid Moortgat-Pick | Towards Measuring the Stop Mixing Angle at the LHC | 30 pages, 11 figures, version to appear in EPJC | Eur.Phys.J.C71:1517,2011 | 10.1140/epjc/s10052-010-1517-x | IPPP-09-55, DCPT-09-110 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We address the question of how to determine the stop mixing angle and its
CP-violating phase at the LHC. As an observable we discuss ratios of branching
ratios for different decay modes of the light stop ~t_1 to charginos and
neutralinos. These observables can have a very strong dependence on the
parameters of the stop sector. We discuss in detail the origin of these
effects. Using various combinations of the ratios of branching ratios we argue
that, depending on the scenario, the observable may be promising in exposing
the light stop mass, the mixing angle and the CP phase. This will, however,
require a good knowledge of the supersymmetric spectrum, which is likely to be
achievable only in combination with results from a linear collider.
| [
{
"created": "Thu, 17 Sep 2009 12:04:11 GMT",
"version": "v1"
},
{
"created": "Thu, 6 Jan 2011 13:17:54 GMT",
"version": "v2"
}
] | 2015-03-13 | [
[
"Rolbiecki",
"Krzysztof",
""
],
[
"Tattersall",
"Jamie",
""
],
[
"Moortgat-Pick",
"Gudrid",
""
]
] | We address the question of how to determine the stop mixing angle and its CP-violating phase at the LHC. As an observable we discuss ratios of branching ratios for different decay modes of the light stop ~t_1 to charginos and neutralinos. These observables can have a very strong dependence on the parameters of the stop sector. We discuss in detail the origin of these effects. Using various combinations of the ratios of branching ratios we argue that, depending on the scenario, the observable may be promising in exposing the light stop mass, the mixing angle and the CP phase. This will, however, require a good knowledge of the supersymmetric spectrum, which is likely to be achievable only in combination with results from a linear collider. |
1601.00602 | Karim Ghorbani | Karim Ghorbani (Arak U.) and Parsa Hossein Ghorbani (IPM, Tehran) | The LHC upper bounds for $pp \to \text{diboson}$, $t\bar t$ cross
section on fermionic dark matter | 14 pages, text modified by adding a computation on pp into dibosons
and tt, published version | null | 10.1142/S0217751X17501317 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The ATLAS report in August 2016 provided an upper limit for the $pp\to$
diboson and $t\bar t$ cross sections. We consider a pseudoscalar-mediated
fermionic dark matter together with gluon and photon effective operators
interacting with the pseudoscalar. Choosing the resonance mass being
$m_\rho=200, 750$ GeV and $2$ TeV, beside the relic density and the invisible
Higgs decay constraints we constrain more the space of parameters with the
diboson and $t\bar t$ cross section upper bounds. We finally provide some
benchmarks consistent with all the constraints. Having exploited a pseudoscalar
mediator, the DM-nucleon cross section is velocity suppressed so that the model
evades easily the bounds put by the future direct detection experiments such as
XENON1T.
| [
{
"created": "Mon, 4 Jan 2016 18:38:27 GMT",
"version": "v1"
},
{
"created": "Thu, 28 Apr 2016 06:04:00 GMT",
"version": "v2"
},
{
"created": "Sat, 29 Jul 2017 16:19:17 GMT",
"version": "v3"
}
] | 2017-08-01 | [
[
"Ghorbani",
"Karim",
"",
"Arak U."
],
[
"Ghorbani",
"Parsa Hossein",
"",
"IPM, Tehran"
]
] | The ATLAS report in August 2016 provided an upper limit for the $pp\to$ diboson and $t\bar t$ cross sections. We consider a pseudoscalar-mediated fermionic dark matter together with gluon and photon effective operators interacting with the pseudoscalar. Choosing the resonance mass being $m_\rho=200, 750$ GeV and $2$ TeV, beside the relic density and the invisible Higgs decay constraints we constrain more the space of parameters with the diboson and $t\bar t$ cross section upper bounds. We finally provide some benchmarks consistent with all the constraints. Having exploited a pseudoscalar mediator, the DM-nucleon cross section is velocity suppressed so that the model evades easily the bounds put by the future direct detection experiments such as XENON1T. |
0901.0283 | Itay Yavin | Matthew Baumgart, Clifford Cheung, Joshua T. Ruderman, Lian-Tao Wang,
and Itay Yavin | Non-Abelian Dark Sectors and Their Collider Signatures | 44 pages, 25 figures, version published in JHEP | JHEP 0904:014,2009 | 10.1088/1126-6708/2009/04/014 | null | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Motivated by the recent proliferation of observed astrophysical anomalies,
Arkani-Hamed et al. have proposed a model in which dark matter is charged under
a non-abelian "dark" gauge symmetry that is broken at ~ 1 GeV. In this paper,
we present a survey of concrete models realizing such a scenario, followed by a
largely model-independent study of collider phenomenology relevant to the
Tevatron and the LHC. We address some model building issues that are easily
surmounted to accommodate the astrophysics. While SUSY is not necessary, we
argue that it is theoretically well-motivated because the GeV scale is
automatically generated. Specifically, we propose a novel mechanism by which
mixed D-terms in the dark sector induce either SUSY breaking or a super-Higgs
mechanism precisely at a GeV. Furthermore, we elaborate on the original
proposal of Arkani-Hamed et al. in which the dark matter acts as a messenger of
gauge mediation to the dark sector. In our collider analysis we present
cross-sections for dominant production channels and lifetime estimates for
primary decay modes. We find that dark gauge bosons can be produced at the
Tevatron and the LHC, either through a process analogous to prompt photon
production or through a rare Z decay channel. Dark gauge bosons will decay back
to the SM via "lepton jets" which typically contain >2 and as many as 8
leptons, significantly improving their discovery potential. Since SUSY decays
from the MSSM will eventually cascade down to these lepton jets, the discovery
potential for direct electroweak-ino production may also be improved.
Exploiting the unique kinematics, we find that it is possible to reconstruct
the mass of the MSSM LSP. We also present decay channels with displaced
vertices and multiple leptons with partially correlated impact parameters.
| [
{
"created": "Mon, 5 Jan 2009 19:51:25 GMT",
"version": "v1"
},
{
"created": "Fri, 3 Apr 2009 12:11:45 GMT",
"version": "v2"
}
] | 2009-04-17 | [
[
"Baumgart",
"Matthew",
""
],
[
"Cheung",
"Clifford",
""
],
[
"Ruderman",
"Joshua T.",
""
],
[
"Wang",
"Lian-Tao",
""
],
[
"Yavin",
"Itay",
""
]
] | Motivated by the recent proliferation of observed astrophysical anomalies, Arkani-Hamed et al. have proposed a model in which dark matter is charged under a non-abelian "dark" gauge symmetry that is broken at ~ 1 GeV. In this paper, we present a survey of concrete models realizing such a scenario, followed by a largely model-independent study of collider phenomenology relevant to the Tevatron and the LHC. We address some model building issues that are easily surmounted to accommodate the astrophysics. While SUSY is not necessary, we argue that it is theoretically well-motivated because the GeV scale is automatically generated. Specifically, we propose a novel mechanism by which mixed D-terms in the dark sector induce either SUSY breaking or a super-Higgs mechanism precisely at a GeV. Furthermore, we elaborate on the original proposal of Arkani-Hamed et al. in which the dark matter acts as a messenger of gauge mediation to the dark sector. In our collider analysis we present cross-sections for dominant production channels and lifetime estimates for primary decay modes. We find that dark gauge bosons can be produced at the Tevatron and the LHC, either through a process analogous to prompt photon production or through a rare Z decay channel. Dark gauge bosons will decay back to the SM via "lepton jets" which typically contain >2 and as many as 8 leptons, significantly improving their discovery potential. Since SUSY decays from the MSSM will eventually cascade down to these lepton jets, the discovery potential for direct electroweak-ino production may also be improved. Exploiting the unique kinematics, we find that it is possible to reconstruct the mass of the MSSM LSP. We also present decay channels with displaced vertices and multiple leptons with partially correlated impact parameters. |
hep-ph/0310016 | Stefano Forte | Guido Altarelli, Richard D. Ball, Stefano Forte | An Improved Splitting Function for Small x Evolution | 5 pages, 2 figures, presented by G.A.at DIS2003 | null | null | CERN-TH/2003-238, Edinburgh 2003/18, IFUM-774/FT | hep-ph | null | We summarize our recent result for a splitting function for small x evolution
which includes resummed small x logarithms deduced from the leading order BFKL
equation with the inclusion of running coupling effects. We compare this
improved splitting function with alternative approaches.
| [
{
"created": "Wed, 1 Oct 2003 13:11:38 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Altarelli",
"Guido",
""
],
[
"Ball",
"Richard D.",
""
],
[
"Forte",
"Stefano",
""
]
] | We summarize our recent result for a splitting function for small x evolution which includes resummed small x logarithms deduced from the leading order BFKL equation with the inclusion of running coupling effects. We compare this improved splitting function with alternative approaches. |
hep-ph/0601052 | Joseph Schechter | Deirdre Black, Masayasu Harada and Joseph Schechter | Chiral approach to phi radiative decays | 26 pages, 10 figures, dedicated to celebration of sixtieth birthday
of Rafael Sorkin | Phys.Rev. D73 (2006) 054017 | 10.1103/PhysRevD.73.054017 | DPNU-05-19, SU-4252-820 | hep-ph | null | The radiative decays of the phi meson are known to be a good source of
information about the a0(980) and f0(980) scalar mesons. We discuss these
decays starting from a non-linear model Lagrangian which maintains the (broken)
chiral symmetry for the pseudoscalar (P), scalar (S) and vector (V) nonets
involved. The characteristic feature is derivative coupling for the SPP
interaction. In an initial approximation which models all the scalar nonet
radiative processes together with the help of a point like vertex, it is noted
that the derivative coupling prevents the a0 and f0 resonance peaks from
getting washed out (by falling phase space). However, the shapes of the two
final PP mass distributions do not agree well with the experimental ones. For
improving the situation we verify that the inclusion of the charged K meson
loop diagrams in the model does reproduce the experimental spectrum shapes in
the resonance region. The derivative coupling introduces quadratic as well as
logaritmic divergneces in this calculation. Using dimensional regularization we
show that these divergences actually cancel out among the four diagrams, as
expected from gauge invariance. We point out the features which are expected to
be important for further work on this model and for learning more about the
puzzling scalar mesons.
| [
{
"created": "Fri, 6 Jan 2006 19:06:28 GMT",
"version": "v1"
}
] | 2009-11-11 | [
[
"Black",
"Deirdre",
""
],
[
"Harada",
"Masayasu",
""
],
[
"Schechter",
"Joseph",
""
]
] | The radiative decays of the phi meson are known to be a good source of information about the a0(980) and f0(980) scalar mesons. We discuss these decays starting from a non-linear model Lagrangian which maintains the (broken) chiral symmetry for the pseudoscalar (P), scalar (S) and vector (V) nonets involved. The characteristic feature is derivative coupling for the SPP interaction. In an initial approximation which models all the scalar nonet radiative processes together with the help of a point like vertex, it is noted that the derivative coupling prevents the a0 and f0 resonance peaks from getting washed out (by falling phase space). However, the shapes of the two final PP mass distributions do not agree well with the experimental ones. For improving the situation we verify that the inclusion of the charged K meson loop diagrams in the model does reproduce the experimental spectrum shapes in the resonance region. The derivative coupling introduces quadratic as well as logaritmic divergneces in this calculation. Using dimensional regularization we show that these divergences actually cancel out among the four diagrams, as expected from gauge invariance. We point out the features which are expected to be important for further work on this model and for learning more about the puzzling scalar mesons. |
1105.5529 | Dorota Sokolowska | Maria Krawczyk, Dorota Sokolowska | The Inert Doublet Model and evolution of the Universe | 4 pages, 5 figures (eps), talk presented at 10th Hellenic School on
Elementary Particle Physics and Gravity, Corfu 2010. Proceedings are to be
published in Fortschritte der Physik | Fortschr. Phys. 59, No. 11 - 12, 1098 - 1102 (2011) | 10.1002/prop.201100070 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Inert Doublet Model (IDM) is a minimal extension of the Standard Model with
the second scalar doublet that may provide a Dark Matter candidate. In this
paper we consider the different variants of the evolution of the Universe after
inflation, that lead towards the Inert phase today.
| [
{
"created": "Fri, 27 May 2011 11:24:15 GMT",
"version": "v1"
}
] | 2016-02-03 | [
[
"Krawczyk",
"Maria",
""
],
[
"Sokolowska",
"Dorota",
""
]
] | Inert Doublet Model (IDM) is a minimal extension of the Standard Model with the second scalar doublet that may provide a Dark Matter candidate. In this paper we consider the different variants of the evolution of the Universe after inflation, that lead towards the Inert phase today. |
1203.3631 | Ibragim Alikhanov | I. Alikhanov | Single vector leptoquark production at hadron colliders due to direct
lepton-gluon interaction | 26 pages, 14 figures. A new figure inserted. Text in the conclusions
added. Accepted for publication in Phys. Lett. B | Phys.Lett.B717:425-429,2012 | 10.1016/j.physletb.2012.09.068 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The cross section of single vector leptoquark production in direct
lepton-gluon interaction is calculated. In a model independent analysis an
effective Lagrangian describing the most general $C$ and $P$ conserving
coupling of the leptoquarks to gluons is considered. An analytical expression
is derived for the cross section in the case of anomalous vector leptoquark
couplings to the gluon field. The cross sections of inclusive production of
($eq$)-, ($\mu q$)- and ($\tau q$)-type vector leptoquarks in $ep$ and $pp$
collisions due to direct lepton-gluon interaction are evaluated for $q=u, b,
t$. Dependences of the cross sections on the anomalous couplings are
investigated. The obtained results can be useful for studies at $ep$ colliders
and the LHC.
| [
{
"created": "Fri, 16 Mar 2012 08:22:12 GMT",
"version": "v1"
},
{
"created": "Thu, 4 Oct 2012 07:55:10 GMT",
"version": "v2"
}
] | 2012-10-17 | [
[
"Alikhanov",
"I.",
""
]
] | The cross section of single vector leptoquark production in direct lepton-gluon interaction is calculated. In a model independent analysis an effective Lagrangian describing the most general $C$ and $P$ conserving coupling of the leptoquarks to gluons is considered. An analytical expression is derived for the cross section in the case of anomalous vector leptoquark couplings to the gluon field. The cross sections of inclusive production of ($eq$)-, ($\mu q$)- and ($\tau q$)-type vector leptoquarks in $ep$ and $pp$ collisions due to direct lepton-gluon interaction are evaluated for $q=u, b, t$. Dependences of the cross sections on the anomalous couplings are investigated. The obtained results can be useful for studies at $ep$ colliders and the LHC. |
1305.3173 | Fu-Sheng Yu | Fu-Sheng Yu, Emi Kou, Cai-Dian L\"u | Photon Polarization in the b->s gamma processes in the Left-Right
Symmetric Model | 30pages, 5 figures, published version; references added | JHEP12(2013)102 | 10.1007/JHEP12(2013)102 | null | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The circular-polarization of the photon in the radiative B decays is
dominantly left-handed in the Standard Model (SM), but the right-handed
polarization may be enhanced in some new physics models with right-handed
currents, such as the Left-Right Symmetric Model (LRSM). In this article, we
investigate how large this wrong polarization could be within the allowed
parameter space of the LRSM. We show that in LRSM, the right-handed
polarization of the photon in the $b\to s\gamma$ processes could be largely
enhanced by the $W_L-W_R$ mixing contributions because of the helicity flip on
the internal top quark line of the penguin diagrams and the enhancement by the
CKM factor $V_{ts}^R/V_{ts}^L$. We discuss the sensitivity of the proposed
methods to determine the $b\to s\gamma$ photon polarization to the LRSM as well
as their complementary role compared to the direct search of right-handed
charged gauge bosons at LHC.
| [
{
"created": "Tue, 14 May 2013 14:58:36 GMT",
"version": "v1"
},
{
"created": "Fri, 3 Jan 2014 07:45:29 GMT",
"version": "v2"
}
] | 2014-01-06 | [
[
"Yu",
"Fu-Sheng",
""
],
[
"Kou",
"Emi",
""
],
[
"Lü",
"Cai-Dian",
""
]
] | The circular-polarization of the photon in the radiative B decays is dominantly left-handed in the Standard Model (SM), but the right-handed polarization may be enhanced in some new physics models with right-handed currents, such as the Left-Right Symmetric Model (LRSM). In this article, we investigate how large this wrong polarization could be within the allowed parameter space of the LRSM. We show that in LRSM, the right-handed polarization of the photon in the $b\to s\gamma$ processes could be largely enhanced by the $W_L-W_R$ mixing contributions because of the helicity flip on the internal top quark line of the penguin diagrams and the enhancement by the CKM factor $V_{ts}^R/V_{ts}^L$. We discuss the sensitivity of the proposed methods to determine the $b\to s\gamma$ photon polarization to the LRSM as well as their complementary role compared to the direct search of right-handed charged gauge bosons at LHC. |
hep-ph/9507201 | null | Riotto Antonio | Are oscillons present during a first order electroweak phase transition? | 13 pages, 2 figures available upon request | Phys.Lett.B365:64-71,1996 | 10.1016/0370-2693(95)01239-7 | SISSA-AP/95-79 preprint | hep-ph | null | It has been recently argued that localized, unstable, but extremely
long-lived configurations, called oscillons, could affect the dynamics of a
first order electroweak phase transition in an appreciable way. Treating the
amplitude and the size of subcritical bubbles as statistical degrees of
freedom, we show that thermal fluctuations are not strong enough to generate
subcritical configurations able to settle into a an oscillon long-lived regime.
| [
{
"created": "Mon, 3 Jul 1995 10:08:23 GMT",
"version": "v1"
}
] | 2010-11-19 | [
[
"Antonio",
"Riotto",
""
]
] | It has been recently argued that localized, unstable, but extremely long-lived configurations, called oscillons, could affect the dynamics of a first order electroweak phase transition in an appreciable way. Treating the amplitude and the size of subcritical bubbles as statistical degrees of freedom, we show that thermal fluctuations are not strong enough to generate subcritical configurations able to settle into a an oscillon long-lived regime. |
hep-ph/0112232 | Ernest Ma | Ernest Ma (UC Riverside) | New U(1) Gauge Symmetry of Quarks and Leptons | minor word changes, to appear in MPLA | Mod.Phys.Lett. A17 (2002) 535-541 | 10.1142/S0217732302006679 | UCRHEP-T327 (Dec 2001) | hep-ph | null | Instead of anchoring the seesaw mechanism with the conventional heavy
right-handed neutrino singlet, a small Majorana neutrino mass may be obtained
just as well with the addition of a heavy triplet of leptons per family to the
minimal standard model of particle interactions. The resulting model is shown
to have the remarkable property of accommodating a new U(1) symmetry which is
anomaly-free and may thus be gauged. There are many possible phenomenological
consequences of this proposal which may be already relevant in explaining one
or two recent potential experimental discrepancies.
| [
{
"created": "Mon, 17 Dec 2001 20:21:04 GMT",
"version": "v1"
},
{
"created": "Tue, 2 Apr 2002 16:23:59 GMT",
"version": "v2"
}
] | 2009-11-07 | [
[
"Ma",
"Ernest",
"",
"UC Riverside"
]
] | Instead of anchoring the seesaw mechanism with the conventional heavy right-handed neutrino singlet, a small Majorana neutrino mass may be obtained just as well with the addition of a heavy triplet of leptons per family to the minimal standard model of particle interactions. The resulting model is shown to have the remarkable property of accommodating a new U(1) symmetry which is anomaly-free and may thus be gauged. There are many possible phenomenological consequences of this proposal which may be already relevant in explaining one or two recent potential experimental discrepancies. |
0705.2617 | Zhang Xiao-Bing | Xiao-Bing Zhang | Note on color neutral solutions of the $K^0$ condensed color-flavor
locked phase | null | null | null | null | hep-ph | null | In the presence of nonzero strange quark mass $m_s$, we investigate color
neutrality in the $K^0$ condensed phase of color-flavor locked quark matter. By
treating the $m_s$ effects on both kaon condensate and Fermi-surface phenomenon
self-consistently, we develop a new treatment to evaluate color neutral
solutions within the model-independent framework. It is pointed out that, in
the general sense, the expectation values of gluon fields obtained from
dynamics of Goldstone bosons solely are not identified with the factual color
chemical potentials.
| [
{
"created": "Fri, 18 May 2007 00:19:41 GMT",
"version": "v1"
}
] | 2017-03-07 | [
[
"Zhang",
"Xiao-Bing",
""
]
] | In the presence of nonzero strange quark mass $m_s$, we investigate color neutrality in the $K^0$ condensed phase of color-flavor locked quark matter. By treating the $m_s$ effects on both kaon condensate and Fermi-surface phenomenon self-consistently, we develop a new treatment to evaluate color neutral solutions within the model-independent framework. It is pointed out that, in the general sense, the expectation values of gluon fields obtained from dynamics of Goldstone bosons solely are not identified with the factual color chemical potentials. |
0807.3791 | Mikhail Gorshteyn | M. Gorchtein and A.P. Szczepaniak | Low energy theorem for virtual Compton scattering and generalized sum
rules of the nucleon | 4 pages, 2 figures, revtex4 | Phys.Rev.Lett.101:141601,2008 | 10.1103/PhysRevLett.101.141601 | null | hep-ph hep-ex nucl-ex nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We formulate the low energy theorem for virtual Compton scattering off a
nucleon and examine its consequences for generalized nucleon polarizabilites.
As a result of a new, model independent definition of the low energy limit for
VVCS reaction, all generalized sum rules of the nucleon have continuous limit
for real photons and obtain contributions from the $t$-channel that were not
included previously.
| [
{
"created": "Thu, 24 Jul 2008 04:20:45 GMT",
"version": "v1"
}
] | 2008-11-26 | [
[
"Gorchtein",
"M.",
""
],
[
"Szczepaniak",
"A. P.",
""
]
] | We formulate the low energy theorem for virtual Compton scattering off a nucleon and examine its consequences for generalized nucleon polarizabilites. As a result of a new, model independent definition of the low energy limit for VVCS reaction, all generalized sum rules of the nucleon have continuous limit for real photons and obtain contributions from the $t$-channel that were not included previously. |
1001.2553 | Clark Downum | Frank Close, Clark Downum, Christopher E. Thomas | Novel Charmonium and Bottomonium Spectroscopies due to Deeply Bound
Hadronic Molecules from Single Pion Exchange | 14 pages, 5 figures and 5 tables | Phys.Rev.D81:074033,2010 | 10.1103/PhysRevD.81.074033 | OUTP-10-01P, JLAB-THY-10-1119 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Pion exchange in S-wave between hadrons that are themselves in a relative
S-wave is shown to shift energies by hundreds of MeV, leading to deeply bound
quasi-molecular states. In the case of charmed mesons $D^*,D_1$ a spectroscopy
arises consistent with enigmatic charmonium states observed above 4 GeV in
$e^+e^-$ annihilation. A possible explanation of $Y(4260)\to \psi\pi\pi$ and
$Y(4360) \to \psi'\pi\pi$ is found. We give results for all isospin and
charge-conjugation combinations, and comment on flavor exotic doubly charmed
states and bottomonium analogs. A search in $D\bar{D}3\pi$ is recommended to
test this hypothesis. An exotic $1^{-+}$ is predicted to occur in the vicinity
of the $Y$(4260).
| [
{
"created": "Thu, 14 Jan 2010 20:40:19 GMT",
"version": "v1"
}
] | 2010-05-12 | [
[
"Close",
"Frank",
""
],
[
"Downum",
"Clark",
""
],
[
"Thomas",
"Christopher E.",
""
]
] | Pion exchange in S-wave between hadrons that are themselves in a relative S-wave is shown to shift energies by hundreds of MeV, leading to deeply bound quasi-molecular states. In the case of charmed mesons $D^*,D_1$ a spectroscopy arises consistent with enigmatic charmonium states observed above 4 GeV in $e^+e^-$ annihilation. A possible explanation of $Y(4260)\to \psi\pi\pi$ and $Y(4360) \to \psi'\pi\pi$ is found. We give results for all isospin and charge-conjugation combinations, and comment on flavor exotic doubly charmed states and bottomonium analogs. A search in $D\bar{D}3\pi$ is recommended to test this hypothesis. An exotic $1^{-+}$ is predicted to occur in the vicinity of the $Y$(4260). |
1001.1938 | Ciaran Williams | Ciaran Williams | Higgs + 2 jets: Compact Analytic Results | Talk given at RADCOR 2009 - 9th International Symposium on Radiative
Corrections (Applications of Quantum Field Theory to Phenomenology) October
25 - 30 2009. 6 pages | PoS RADCOR2009:025,2010 | null | IPPP/09/98 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | This report describes the recent efforts to compute analytic formulae for the
Next-to-Leading-Order (NLO) QCD corrections to Higgs plus two jet production at
hadron colliders. In these calculations the Higgs boson couples to gluons via a
top-quark loop which is integrated out to form an effective vertex. The
amplitudes are further simplified by splitting the real Higgs scalar into the
sum of two complex scalars phi and phi^dagger. Four-dimensional unitarity is
used to construct the cut-containing pieces of the amplitude, while a variety
of bootstrap and Feynman diagram techniques are used to construct the rational
pieces. The results described here are valid in the limit of a large top quark
mass and when the transverse momenta of the jets are less than mt.
| [
{
"created": "Tue, 12 Jan 2010 19:07:13 GMT",
"version": "v1"
}
] | 2014-11-20 | [
[
"Williams",
"Ciaran",
""
]
] | This report describes the recent efforts to compute analytic formulae for the Next-to-Leading-Order (NLO) QCD corrections to Higgs plus two jet production at hadron colliders. In these calculations the Higgs boson couples to gluons via a top-quark loop which is integrated out to form an effective vertex. The amplitudes are further simplified by splitting the real Higgs scalar into the sum of two complex scalars phi and phi^dagger. Four-dimensional unitarity is used to construct the cut-containing pieces of the amplitude, while a variety of bootstrap and Feynman diagram techniques are used to construct the rational pieces. The results described here are valid in the limit of a large top quark mass and when the transverse momenta of the jets are less than mt. |
1907.12409 | Hyun Min Lee | Hyun Min Lee | Lectures on Physics Beyond the Standard Model | 61 pages, no figures, Lectures at 2019 IBS-CTPU Summer School on
Cosmology and Particle Physics, 22-26 July, 2019, Daejeon, Korea, v2:
references added, v3: typos corrected and improved discussion, v4: expanded
discussion with four-form flux relaxation, Journal version | J. Korean Phys. Soc. 78, 985 (2021) | 10.1007/s40042-021-00188-x | null | hep-ph | http://creativecommons.org/licenses/by-nc-sa/4.0/ | We give a brief overview on the successes and theoretical problems of the
Standard Model and discuss the basics of low-scale supersymmetry. We also
address some of recent proposals for physics beyond the Standard Model and the
connection to the production mechanisms for thermal dark matter.
| [
{
"created": "Mon, 29 Jul 2019 13:18:26 GMT",
"version": "v1"
},
{
"created": "Tue, 30 Jul 2019 14:52:47 GMT",
"version": "v2"
},
{
"created": "Tue, 10 Dec 2019 13:17:01 GMT",
"version": "v3"
},
{
"created": "Wed, 7 Apr 2021 07:51:06 GMT",
"version": "v4"
}
] | 2021-06-30 | [
[
"Lee",
"Hyun Min",
""
]
] | We give a brief overview on the successes and theoretical problems of the Standard Model and discuss the basics of low-scale supersymmetry. We also address some of recent proposals for physics beyond the Standard Model and the connection to the production mechanisms for thermal dark matter. |
hep-ph/0208048 | Marco Ciuchini | M. Ciuchini, E. Franco, G. Martinelli, M. Pierini, L. Silvestrini | Charming Penguins Saga | Invited talk at FPCP '02 given by M. Ciuchini, uses econfmacros.tex.
Final version with minor changes to appear in the proceedings | null | null | null | hep-ph | null | We briefly recall the main formulae for computing the B -> K pi branching
ratios within the "charming penguin" approach, present an updated fit to the
data, and explain why we believe that, in general, these fits can hardly be
used to extract gamma.
| [
{
"created": "Tue, 6 Aug 2002 09:44:25 GMT",
"version": "v1"
},
{
"created": "Mon, 9 Sep 2002 10:23:15 GMT",
"version": "v2"
}
] | 2007-05-23 | [
[
"Ciuchini",
"M.",
""
],
[
"Franco",
"E.",
""
],
[
"Martinelli",
"G.",
""
],
[
"Pierini",
"M.",
""
],
[
"Silvestrini",
"L.",
""
]
] | We briefly recall the main formulae for computing the B -> K pi branching ratios within the "charming penguin" approach, present an updated fit to the data, and explain why we believe that, in general, these fits can hardly be used to extract gamma. |
1505.02677 | Harri Niemi | H. Niemi, K. J. Eskola, R. Paatelainen | Event-by-event fluctuations in perturbative QCD + saturation + hydro
model: pinning down QCD matter shear viscosity in ultrarelativistic heavy-ion
collisions | 32 pages, 23 figures | Phys. Rev. C 93, 024907 (2016) | 10.1103/PhysRevC.93.024907 | null | hep-ph nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We introduce an event-by-event perturbative-QCD + saturation + hydro ("EKRT")
framework for ultrarelativistic heavy-ion collisions, where we compute the
produced fluctuating QCD-matter energy densities from next-to-leading order
perturbative QCD using a saturation conjecture to control soft particle
production, and describe the space-time evolution of the QCD matter with
dissipative fluid dynamics, event by event. We perform a simultaneous
comparison of the centrality dependence of hadronic multiplicities, transverse
momentum spectra, and flow coefficients of the azimuth-angle asymmetries,
against the LHC and RHIC measurements. We compare also the computed
event-by-event probability distributions of relative fluctuations of elliptic
flow, and event-plane angle correlations, with the experimental data from Pb+Pb
collisions at the LHC. We show how such a systematic multi-energy and
multi-observable analysis tests the initial state calculation and the
applicability region of hydrodynamics, and in particular how it constrains the
temperature dependence of the shear viscosity-to-entropy ratio of QCD matter in
its different phases in a remarkably consistent manner.
| [
{
"created": "Mon, 11 May 2015 15:52:23 GMT",
"version": "v1"
}
] | 2016-02-17 | [
[
"Niemi",
"H.",
""
],
[
"Eskola",
"K. J.",
""
],
[
"Paatelainen",
"R.",
""
]
] | We introduce an event-by-event perturbative-QCD + saturation + hydro ("EKRT") framework for ultrarelativistic heavy-ion collisions, where we compute the produced fluctuating QCD-matter energy densities from next-to-leading order perturbative QCD using a saturation conjecture to control soft particle production, and describe the space-time evolution of the QCD matter with dissipative fluid dynamics, event by event. We perform a simultaneous comparison of the centrality dependence of hadronic multiplicities, transverse momentum spectra, and flow coefficients of the azimuth-angle asymmetries, against the LHC and RHIC measurements. We compare also the computed event-by-event probability distributions of relative fluctuations of elliptic flow, and event-plane angle correlations, with the experimental data from Pb+Pb collisions at the LHC. We show how such a systematic multi-energy and multi-observable analysis tests the initial state calculation and the applicability region of hydrodynamics, and in particular how it constrains the temperature dependence of the shear viscosity-to-entropy ratio of QCD matter in its different phases in a remarkably consistent manner. |
1704.01757 | Francesco Hautmann | F. Hautmann, H. Jung, A. Lelek, V. Radescu, R. Zlebcik | Soft-gluon resolution scale in QCD evolution equations | Latex, 8 pages, 4 figures | null | 10.1016/j.physletb.2017.07.005 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | QCD evolution equations can be recast in terms of parton branching processes.
We present a new numerical solution of the equations. We show that this
parton-branching solution can be applied to analyze infrared contributions to
evolution, order-by-order in the strong coupling $\alpha_s$, as a function of
the soft-gluon resolution scale parameter. We examine the cases of
transverse-momentum ordering and angular ordering. We illustrate that this
approach can be used to treat distributions which depend both on longitudinal
and on transverse momenta.
| [
{
"created": "Thu, 6 Apr 2017 09:32:53 GMT",
"version": "v1"
}
] | 2017-08-23 | [
[
"Hautmann",
"F.",
""
],
[
"Jung",
"H.",
""
],
[
"Lelek",
"A.",
""
],
[
"Radescu",
"V.",
""
],
[
"Zlebcik",
"R.",
""
]
] | QCD evolution equations can be recast in terms of parton branching processes. We present a new numerical solution of the equations. We show that this parton-branching solution can be applied to analyze infrared contributions to evolution, order-by-order in the strong coupling $\alpha_s$, as a function of the soft-gluon resolution scale parameter. We examine the cases of transverse-momentum ordering and angular ordering. We illustrate that this approach can be used to treat distributions which depend both on longitudinal and on transverse momenta. |
1909.07429 | T\'essio B. de Melo | Tessio B. de Melo, Farinaldo S. Queiroz, Yoxara Villamizar | Doubly Charged Scalar at the High-Luminosity and High-Energy LHC | 7 pages, 7 figures, 1 table | null | 10.1142/S0217751X19501574 | IIPDM-2019 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Doubly charged scalars are common figures in several beyond the Standard
Model studies, especially those related to neutrino masses. In this work, we
estimate the High-Luminosity (HL-LHC) and High-Energy LHC (HE-LHC) sensitivity
to doubly charged scalars assuming they decay promptly and exclusively into
charged leptons. Our study focuses on the fit to the same-sign dilepton mass
spectra and it is based on proton-proton collisions at $13$ TeV, $14$ TeV and
$27$ TeV with integrated luminosity of $\mathcal{L}=139 fb^{-1}, 3 $ab$^{-1}$
and $15$ab$^{-1}$. We find that HL-LHC may probe doubly charged scalars masses
up to $2.3$ TeV, whereas HE-LHC can impressively probe masses up to $3$ TeV,
conclusively constituting a complementary and important probe to signs of
doubly charged scalars in lepton flavor violation decays and lepton-lepton
colliders.
| [
{
"created": "Mon, 16 Sep 2019 18:25:36 GMT",
"version": "v1"
}
] | 2019-10-23 | [
[
"de Melo",
"Tessio B.",
""
],
[
"Queiroz",
"Farinaldo S.",
""
],
[
"Villamizar",
"Yoxara",
""
]
] | Doubly charged scalars are common figures in several beyond the Standard Model studies, especially those related to neutrino masses. In this work, we estimate the High-Luminosity (HL-LHC) and High-Energy LHC (HE-LHC) sensitivity to doubly charged scalars assuming they decay promptly and exclusively into charged leptons. Our study focuses on the fit to the same-sign dilepton mass spectra and it is based on proton-proton collisions at $13$ TeV, $14$ TeV and $27$ TeV with integrated luminosity of $\mathcal{L}=139 fb^{-1}, 3 $ab$^{-1}$ and $15$ab$^{-1}$. We find that HL-LHC may probe doubly charged scalars masses up to $2.3$ TeV, whereas HE-LHC can impressively probe masses up to $3$ TeV, conclusively constituting a complementary and important probe to signs of doubly charged scalars in lepton flavor violation decays and lepton-lepton colliders. |
0801.2374 | Laura Reina | Fernando Febres Cordero, Laura Reina, Doreen Wackeroth | NLO QCD corrections to W-b-bbar and Z-b-bbar production | 6 pages, 6 eps figures, LaTeX, to appear in the proceedings of the
"8th International Symposium on Radiative Corrections (RADCOR 2007)",
Florence, Italy, October 1-5 | PoS RADCOR2007:012,2007 | null | null | hep-ph | null | We present NLO QCD results for W/Z gauge boson production with bottom quark
pairs at the Tevatron including full bottom-quark mass effects. We study the
impact of QCD corrections on both total cross-section and invariant mass
distribution of the bottom-quark pair. Including NLO QCD corrections greatly
reduces the dependence of the tree-level cross-section on the renormalization
and factorization scales. We also compare our calculation to a calculation that
considers massless bottom quarks and find that the bottom-quark mass effects
amount to about 8-10% of the total NLO QCD cross-section and can impact the
shape of the bottom-quark pair invariant mass distribution, in particular in
the low invariant mass region.
| [
{
"created": "Tue, 15 Jan 2008 20:45:26 GMT",
"version": "v1"
}
] | 2010-12-28 | [
[
"Cordero",
"Fernando Febres",
""
],
[
"Reina",
"Laura",
""
],
[
"Wackeroth",
"Doreen",
""
]
] | We present NLO QCD results for W/Z gauge boson production with bottom quark pairs at the Tevatron including full bottom-quark mass effects. We study the impact of QCD corrections on both total cross-section and invariant mass distribution of the bottom-quark pair. Including NLO QCD corrections greatly reduces the dependence of the tree-level cross-section on the renormalization and factorization scales. We also compare our calculation to a calculation that considers massless bottom quarks and find that the bottom-quark mass effects amount to about 8-10% of the total NLO QCD cross-section and can impact the shape of the bottom-quark pair invariant mass distribution, in particular in the low invariant mass region. |
1909.08443 | Johannes Erdmann | Maura Barros, Nuno Filipe Castro, Johannes Erdmann, Gregor Ge{\ss}ner,
Kevin Kr\"oninger, Salvatore La Cagnina, Ana Peixoto | Study of interference effects in the search for flavour-changing neutral
current interactions involving the top quark and a photon or a $Z$ boson at
the LHC | 8 pages, 3 figures, 2 tables | Eur. Phys. J. Plus 135 (2020) 339 | 10.1140/epjp/s13360-020-00346-3 | null | hep-ph hep-ex | http://creativecommons.org/licenses/by/4.0/ | Flavour-changing neutral-current interactions of the top quark can be
searched for in top-quark pair production with one top quark decaying to an
up-type quark and a neutral boson, and they can be searched for in the single
production of a top quark in association with such a boson. Both processes
interfere if an additional up-type quark is produced in the case of single
production. The impact of these interference effects on searches for
flavour-changing neutral currents at the LHC is studied for the case where the
neutral boson is a photon or a $Z$ boson. Interference effects are found to be
smaller than variations of the renormalisation and factorisation scales.
| [
{
"created": "Wed, 18 Sep 2019 13:37:30 GMT",
"version": "v1"
},
{
"created": "Tue, 24 Mar 2020 09:49:13 GMT",
"version": "v2"
}
] | 2020-04-01 | [
[
"Barros",
"Maura",
""
],
[
"Castro",
"Nuno Filipe",
""
],
[
"Erdmann",
"Johannes",
""
],
[
"Geßner",
"Gregor",
""
],
[
"Kröninger",
"Kevin",
""
],
[
"La Cagnina",
"Salvatore",
""
],
[
"Peixoto",
"Ana",
""
... | Flavour-changing neutral-current interactions of the top quark can be searched for in top-quark pair production with one top quark decaying to an up-type quark and a neutral boson, and they can be searched for in the single production of a top quark in association with such a boson. Both processes interfere if an additional up-type quark is produced in the case of single production. The impact of these interference effects on searches for flavour-changing neutral currents at the LHC is studied for the case where the neutral boson is a photon or a $Z$ boson. Interference effects are found to be smaller than variations of the renormalisation and factorisation scales. |
2112.11993 | Krzysztof Jod{\l}owski | Krzysztof Jod{\l}owski, Leszek Roszkowski, Sebastian Trojanowski | Indirect detection of long-lived particles in a rich dark sector with a
dark vector portal | 19 pages, 11 figures, overview paragraph added in the introduction,
accepted by PRD | null | null | CTPU-PTC-23-51 | hep-ph astro-ph.CO | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Simplified models of light new physics provide a convenient benchmark for
experimental searches for new physics signatures, including dark matter (DM).
However, additional detection modes can arise in less simplified and more
realistic scenarios where new degrees of freedom are invoked. In this study, we
introduce a non-minimal model based on a popular dark photon portal to DM where
the mediator mass is obtained by interactions with the dark Higgs boson which
acts as a long-lived particle. We further add to this scenario a new heavy DM
species secluded from the Standard Model. In this model, which involves light
and heavy particles in the dark sector, we find some new interesting
phenomenological features that lead to complementary probes in intensity
frontier searches for light long-lived particles, indirect detection searches
for dark matter, and cosmic microwave background surveys. We also find possible
non-local effects in the DM indirect detection searches that could
significantly affect the usual detection strategies.
| [
{
"created": "Wed, 22 Dec 2021 16:14:56 GMT",
"version": "v1"
},
{
"created": "Thu, 26 Oct 2023 05:21:20 GMT",
"version": "v2"
},
{
"created": "Tue, 5 Dec 2023 01:55:25 GMT",
"version": "v3"
}
] | 2023-12-06 | [
[
"Jodłowski",
"Krzysztof",
""
],
[
"Roszkowski",
"Leszek",
""
],
[
"Trojanowski",
"Sebastian",
""
]
] | Simplified models of light new physics provide a convenient benchmark for experimental searches for new physics signatures, including dark matter (DM). However, additional detection modes can arise in less simplified and more realistic scenarios where new degrees of freedom are invoked. In this study, we introduce a non-minimal model based on a popular dark photon portal to DM where the mediator mass is obtained by interactions with the dark Higgs boson which acts as a long-lived particle. We further add to this scenario a new heavy DM species secluded from the Standard Model. In this model, which involves light and heavy particles in the dark sector, we find some new interesting phenomenological features that lead to complementary probes in intensity frontier searches for light long-lived particles, indirect detection searches for dark matter, and cosmic microwave background surveys. We also find possible non-local effects in the DM indirect detection searches that could significantly affect the usual detection strategies. |
hep-ph/0412233 | Koske Nishihara | Koske Nishihara | K{\" a}hler Anomaly Effect in Anomaly Mediation Framework | 26 pages, 27 figures | null | null | OU-HET 508 | hep-ph | null | We extend the anomaly mediation mechanism by including the effect due to K{\"
a}hler anomaly. We give a general method analyzing the soft breaking terms in
MSSM by introducing a set of parameters. One of the parameters describes the
magnitude of the K{\" a}hler contribution as opposed to the ordinary super-Weyl
contribution. The other parameters come from the so-called bilinear terms which
are added to the K{\" a}hler potential in order for the gauge singlet scalar
masses squared to be positive. We explore allowed regions of these parameters
by considering present experimental bound and present a new way of looking at
model building.
| [
{
"created": "Thu, 16 Dec 2004 13:44:49 GMT",
"version": "v1"
},
{
"created": "Fri, 25 Mar 2005 08:20:19 GMT",
"version": "v2"
}
] | 2007-05-23 | [
[
"Nishihara",
"Koske",
""
]
] | We extend the anomaly mediation mechanism by including the effect due to K{\" a}hler anomaly. We give a general method analyzing the soft breaking terms in MSSM by introducing a set of parameters. One of the parameters describes the magnitude of the K{\" a}hler contribution as opposed to the ordinary super-Weyl contribution. The other parameters come from the so-called bilinear terms which are added to the K{\" a}hler potential in order for the gauge singlet scalar masses squared to be positive. We explore allowed regions of these parameters by considering present experimental bound and present a new way of looking at model building. |
hep-ph/0311295 | Jeonghyeon Song | Kingman Cheung (NCTS), C.S. Kim (Yonsei Univ.), and Jeonghyeon Song
(Konkuk Univ.) | Probing the Radion-Higgs mixing at hadronic colliders | RevTeX style, 21 pages with 10 eps files | Phys.Rev. D69 (2004) 075011 | 10.1103/PhysRevD.69.075011 | NSC-NCTS-031101, KIAS-P02085 | hep-ph | null | In the Randall-Sundrum model, the radion-Higgs mixing is weakly suppressed by
the effective electroweak scale. One of its novel features would be a sizable
three-point vertex of KK graviton-Higgs-radion. We explored the potential of
the Fermilab Tevatron and the CERN LHC in probing the radion-Higgs mixing via
the associated production of the radion with the Higgs boson. The observation
of the rare decay of the KK gravitons into a Higgs and a radion is then the
direct and exclusive signal of the radion-Higgs mixing. We also studied all the
partial decay widths of the KK gravitons in the presence of the radion-Higgs
mixing, and found that if the mixing parameter is of order one, the decay rate
into a radion and a Higgs boson becomes as large as that into a Higgs boson
pair, with the branching ratio of order 0.001.
| [
{
"created": "Mon, 24 Nov 2003 07:13:32 GMT",
"version": "v1"
}
] | 2009-11-10 | [
[
"Cheung",
"Kingman",
"",
"NCTS"
],
[
"Kim",
"C. S.",
"",
"Yonsei Univ."
],
[
"Song",
"Jeonghyeon",
"",
"Konkuk Univ."
]
] | In the Randall-Sundrum model, the radion-Higgs mixing is weakly suppressed by the effective electroweak scale. One of its novel features would be a sizable three-point vertex of KK graviton-Higgs-radion. We explored the potential of the Fermilab Tevatron and the CERN LHC in probing the radion-Higgs mixing via the associated production of the radion with the Higgs boson. The observation of the rare decay of the KK gravitons into a Higgs and a radion is then the direct and exclusive signal of the radion-Higgs mixing. We also studied all the partial decay widths of the KK gravitons in the presence of the radion-Higgs mixing, and found that if the mixing parameter is of order one, the decay rate into a radion and a Higgs boson becomes as large as that into a Higgs boson pair, with the branching ratio of order 0.001. |
0905.0168 | Christopher Lee | Christopher Lee, Andrew Hornig, and Grigory Ovanesyan | Probing the Structure of Jets: Factorized and Resummed Angularity
Distributions in SCET | 8 pages, 2 figures. Contribution to the proceedings of EFT'09,
International Workshop on Effective Field Theories: from the Pion to the
Upsilon, 2-6 February 2009, Valencia (Spain) | null | null | UCB-PTH-09/13 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Using the framework of soft-collinear effective theory (SCET), we factorize
and calculate $e^+e^-$ angularity distributions, including perturbative
resummation and the incorporation of a universal model for the nonperturbative
soft function. Angularities $\tau_a$ are a class of event shapes varying in
their sensitivity to the substructure of jets in the final state, controlled by
a continuous parameter $a<2$. We calculate the jet and soft functions in
factorized angularity distributions for all $a<1$ to first order in the strong
coupling $\alpha_s$ and resum large logarithms to next-to-leading logarithmic
(NLL) accuracy. We employ a universal model for the nonperturbative soft
function with a gap parameter which cancels the renormalon ambiguity in the
partonic soft function.
| [
{
"created": "Mon, 4 May 2009 17:59:42 GMT",
"version": "v1"
}
] | 2009-05-05 | [
[
"Lee",
"Christopher",
""
],
[
"Hornig",
"Andrew",
""
],
[
"Ovanesyan",
"Grigory",
""
]
] | Using the framework of soft-collinear effective theory (SCET), we factorize and calculate $e^+e^-$ angularity distributions, including perturbative resummation and the incorporation of a universal model for the nonperturbative soft function. Angularities $\tau_a$ are a class of event shapes varying in their sensitivity to the substructure of jets in the final state, controlled by a continuous parameter $a<2$. We calculate the jet and soft functions in factorized angularity distributions for all $a<1$ to first order in the strong coupling $\alpha_s$ and resum large logarithms to next-to-leading logarithmic (NLL) accuracy. We employ a universal model for the nonperturbative soft function with a gap parameter which cancels the renormalon ambiguity in the partonic soft function. |
hep-ph/9807202 | Tom Sizer | Andreas W. Schreiber, Tom Sizer and Anthony G. Williams | Dimensionally Regularized Study of Nonperturbative Quenched QED | 9 pages including 4 .eps files comprising 2 figures; uses sprocl.sty.
To appear in the proceedings of the Workshop on Methods in Nonperturbative
Field Theory, Adelaide, Australia, February 1998 | null | null | ADP-98-033/T306 | hep-ph hep-th | null | We study the dimensionally regularized fermion propagator Dyson-Schwinger
equation in quenched nonperturbative QED in an arbitrary covariant gauge using
the Curtis-Pennington vertex and perform nonperturbative renormalization
numerically. The nonperturbative fermion propagator is solved in D=4-2*epsilon
< 4 dimensional Euclidean space for a large number of values of epsilon for two
values of the coupling, alpha=0.6 and alpha=1.5. Results for D=4 are then
obtained by extrapolation to epsilon=0. We compare these results against
previous studies employing a modified ultraviolet cut-off regularization and
find agreement to within the numerical precision of the present calculations.
| [
{
"created": "Wed, 1 Jul 1998 06:00:09 GMT",
"version": "v1"
},
{
"created": "Wed, 8 Jul 1998 01:23:01 GMT",
"version": "v2"
}
] | 2007-05-23 | [
[
"Schreiber",
"Andreas W.",
""
],
[
"Sizer",
"Tom",
""
],
[
"Williams",
"Anthony G.",
""
]
] | We study the dimensionally regularized fermion propagator Dyson-Schwinger equation in quenched nonperturbative QED in an arbitrary covariant gauge using the Curtis-Pennington vertex and perform nonperturbative renormalization numerically. The nonperturbative fermion propagator is solved in D=4-2*epsilon < 4 dimensional Euclidean space for a large number of values of epsilon for two values of the coupling, alpha=0.6 and alpha=1.5. Results for D=4 are then obtained by extrapolation to epsilon=0. We compare these results against previous studies employing a modified ultraviolet cut-off regularization and find agreement to within the numerical precision of the present calculations. |
hep-ph/9211252 | null | S. Jadach, B.F.L. Ward and S.A. Yost | Exact Results on e+ e- --> e+ e- + 2 Photons at SLC/LEP Energies | 16 pages(LaTeX), UTHEP-92-0601 (contains corrected figures) | Phys.Rev. D47 (1993) 2682-2689 | 10.1103/PhysRevD.47.2682 | null | hep-ph | null | We use the spinor methods of the CALKUL collaboration, as realized by Xu,
Zhang and Chang, to calculate the differential cross section for e+ e- --> e+
e- + 2 photons for c.m.s. energies in the SLC/LEP regime. An explicit complete
formula for the respective cross section is obtained. The leading log
approximation is used to check the formula. Applications of the formula to high
precision luminosity calculations at SLC/LEP are discussed.
| [
{
"created": "Mon, 16 Nov 1992 16:20:38 GMT",
"version": "v1"
},
{
"created": "Wed, 30 Mar 1994 21:30:09 GMT",
"version": "v2"
}
] | 2009-10-22 | [
[
"Jadach",
"S.",
""
],
[
"Ward",
"B. F. L.",
""
],
[
"Yost",
"S. A.",
""
]
] | We use the spinor methods of the CALKUL collaboration, as realized by Xu, Zhang and Chang, to calculate the differential cross section for e+ e- --> e+ e- + 2 photons for c.m.s. energies in the SLC/LEP regime. An explicit complete formula for the respective cross section is obtained. The leading log approximation is used to check the formula. Applications of the formula to high precision luminosity calculations at SLC/LEP are discussed. |
2209.07391 | Manuel Toharia | Mariana Frank, Nima Pourtolami and Manuel Toharia | Additional Higgs bosons: Supersymmetry or warped extra dimensions? | 7 pages, 2 figures, 3 tables | null | 10.1016/j.physletb.2022.137547 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We investigate and compare additional CP-even, CP-odd and charged scalar
states appearing in two popular Beyond the Standard Model scenarios. We focus
on the simplest possible Higgs sector within warped extra-dimensions and
supersymmetry, with the aim to differentiate between them. In each case, we
analyze the couplings of the new Higgs states, looking for distinguishing
signatures. We show that the couplings of the Standard Model gauge bosons to
the first Kaluza-Klein Higgs states of the extra-dimensional setup (CP-even,
CP-odd and charged) are very similar to those of the heavy Higgs states of the
MSSM in the decoupling region. We also find that the Yukawa couplings in the
extra-dimensional scenario can mimic the different types of Yukawa couplings of
general Two-Higgs Doublet Models, in particular the so-called Type-II
couplings, which are similar to those in the MSSM.
| [
{
"created": "Thu, 15 Sep 2022 15:53:21 GMT",
"version": "v1"
}
] | 2022-11-09 | [
[
"Frank",
"Mariana",
""
],
[
"Pourtolami",
"Nima",
""
],
[
"Toharia",
"Manuel",
""
]
] | We investigate and compare additional CP-even, CP-odd and charged scalar states appearing in two popular Beyond the Standard Model scenarios. We focus on the simplest possible Higgs sector within warped extra-dimensions and supersymmetry, with the aim to differentiate between them. In each case, we analyze the couplings of the new Higgs states, looking for distinguishing signatures. We show that the couplings of the Standard Model gauge bosons to the first Kaluza-Klein Higgs states of the extra-dimensional setup (CP-even, CP-odd and charged) are very similar to those of the heavy Higgs states of the MSSM in the decoupling region. We also find that the Yukawa couplings in the extra-dimensional scenario can mimic the different types of Yukawa couplings of general Two-Higgs Doublet Models, in particular the so-called Type-II couplings, which are similar to those in the MSSM. |
hep-ph/9611405 | Bhaskar Dutta | B. Dutta and S. Nandi | Texture of fermion mass matrices in partially unified theories | 10 pages(Latex) | Phys.Rev. D59 (1999) 013013 | 10.1103/PhysRevD.59.013013 | OITS-617, OSURN-318, UTEXAS-HEP-96-18, DOE-ER 40757-087 | hep-ph | null | We investigate the texture of fermion mass matrices in theories with partial
unification (for example $ SU(2)_L\times SU(2)_R\times SU(4)_c$) at a scale
$\sim 10^{12}$ GeV. Starting with the low energy values of the masses and the
mixing angles, we find only two viable textures with atmost four texture zeros.
One of these corresponds to a somewhat modified Fritzsch textures. A
theoretical derivataion of these textures leads to new interesting relations
among the masses and the mixing angles.
| [
{
"created": "Sun, 24 Nov 1996 19:34:11 GMT",
"version": "v1"
}
] | 2009-10-30 | [
[
"Dutta",
"B.",
""
],
[
"Nandi",
"S.",
""
]
] | We investigate the texture of fermion mass matrices in theories with partial unification (for example $ SU(2)_L\times SU(2)_R\times SU(4)_c$) at a scale $\sim 10^{12}$ GeV. Starting with the low energy values of the masses and the mixing angles, we find only two viable textures with atmost four texture zeros. One of these corresponds to a somewhat modified Fritzsch textures. A theoretical derivataion of these textures leads to new interesting relations among the masses and the mixing angles. |
hep-ph/0509019 | Axel Weber | A. Weber | Fine and hyperfine structure in different bound systems | 36 pages, 2 figures | null | null | null | hep-ph hep-th nucl-th | null | We demonstrate that the generalized Gell-Mann-Low theorem permits for a
systematic expansion around the nonrelativistic limit when applied to bound
states in the Wick-Cutkosky model, Yukawa theory, and QED (in Coulomb gauge).
We apply this expansion to obtain new results for the fine and hyperfine
structure of bound states in the cases of the Wick-Cutkosky model and Yukawa
theory, and reproduce correctly the fine and hyperfine structure of hydrogenic
systems.
| [
{
"created": "Fri, 2 Sep 2005 17:49:25 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Weber",
"A.",
""
]
] | We demonstrate that the generalized Gell-Mann-Low theorem permits for a systematic expansion around the nonrelativistic limit when applied to bound states in the Wick-Cutkosky model, Yukawa theory, and QED (in Coulomb gauge). We apply this expansion to obtain new results for the fine and hyperfine structure of bound states in the cases of the Wick-Cutkosky model and Yukawa theory, and reproduce correctly the fine and hyperfine structure of hydrogenic systems. |
1612.07725 | Alexandre Alves | Alexandre Alves | Stacking machine learning classifiers to identify Higgs bosons at the
LHC | 20 pages, 4 figures, 3 tables. Version published in the Journal of
Instrumentation | null | 10.1088/1748-0221/12/05/T05005 | null | hep-ph cs.LG physics.data-an | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Machine learning (ML) algorithms have been employed in the problem of
classifying signal and background events with high accuracy in particle
physics. In this paper, we compare the performance of a widespread ML
technique, namely, \emph{stacked generalization}, against the results of two
state-of-art algorithms: (1) a deep neural network (DNN) in the task of
discovering a new neutral Higgs boson and (2) a scalable machine learning
system for tree boosting, in the Standard Model Higgs to tau leptons channel,
both at the 8 TeV LHC. In a cut-and-count analysis, \emph{stacking} three
algorithms performed around 16\% worse than DNN but demanding far less
computation efforts, however, the same \emph{stacking} outperforms boosted
decision trees. Using the stacked classifiers in a multivariate statistical
analysis (MVA), on the other hand, significantly enhances the statistical
significance compared to cut-and-count in both Higgs processes, suggesting that
combining an ensemble of simpler and faster ML algorithms with MVA tools is a
better approach than building a complex state-of-art algorithm for
cut-and-count.
| [
{
"created": "Wed, 21 Dec 2016 20:01:37 GMT",
"version": "v1"
},
{
"created": "Tue, 7 Feb 2017 01:07:42 GMT",
"version": "v2"
},
{
"created": "Tue, 30 May 2017 19:03:03 GMT",
"version": "v3"
}
] | 2017-06-01 | [
[
"Alves",
"Alexandre",
""
]
] | Machine learning (ML) algorithms have been employed in the problem of classifying signal and background events with high accuracy in particle physics. In this paper, we compare the performance of a widespread ML technique, namely, \emph{stacked generalization}, against the results of two state-of-art algorithms: (1) a deep neural network (DNN) in the task of discovering a new neutral Higgs boson and (2) a scalable machine learning system for tree boosting, in the Standard Model Higgs to tau leptons channel, both at the 8 TeV LHC. In a cut-and-count analysis, \emph{stacking} three algorithms performed around 16\% worse than DNN but demanding far less computation efforts, however, the same \emph{stacking} outperforms boosted decision trees. Using the stacked classifiers in a multivariate statistical analysis (MVA), on the other hand, significantly enhances the statistical significance compared to cut-and-count in both Higgs processes, suggesting that combining an ensemble of simpler and faster ML algorithms with MVA tools is a better approach than building a complex state-of-art algorithm for cut-and-count. |
0812.2564 | Christoph Englert | C. Englert, B. Jager, D. Zeppenfeld | QCD Corrections to Vector-Boson Fusion Processes in Warped Higgsless
Models | 22 pages, 20 figures | JHEP 0903:060,2009 | 10.1088/1126-6708/2009/03/060 | KA-TP-32-2008, SFB/CPP-08-103 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We discuss the signatures of a representative Higgsless model with ideal
fermion delocalization in vector-boson fusion processes, focusing on the gold-
and silver-plated decay modes of the gauge bosons at the CERN-Large Hadron
Collider. For this purpose, we have developed a fully-flexible parton-level
Monte-Carlo program, which allows for the calculation of cross sections and
kinematic distributions within experimentally feasible selection cuts at
NLO-QCD accuracy. We find that Kaluza-Klein resonances give rise to very
distinctive distributions of the decay leptons. Similar to the Standard Model
case, within the Higgsless scenario the perturbative treatment of the
vector-boson scattering processes is under excellent control.
| [
{
"created": "Sat, 13 Dec 2008 17:10:53 GMT",
"version": "v1"
}
] | 2009-03-27 | [
[
"Englert",
"C.",
""
],
[
"Jager",
"B.",
""
],
[
"Zeppenfeld",
"D.",
""
]
] | We discuss the signatures of a representative Higgsless model with ideal fermion delocalization in vector-boson fusion processes, focusing on the gold- and silver-plated decay modes of the gauge bosons at the CERN-Large Hadron Collider. For this purpose, we have developed a fully-flexible parton-level Monte-Carlo program, which allows for the calculation of cross sections and kinematic distributions within experimentally feasible selection cuts at NLO-QCD accuracy. We find that Kaluza-Klein resonances give rise to very distinctive distributions of the decay leptons. Similar to the Standard Model case, within the Higgsless scenario the perturbative treatment of the vector-boson scattering processes is under excellent control. |
hep-ph/0002002 | Raymond R. Volkas | Raymond R Volkas | Mirror Neutrinos and the Early Universe | 7 pages, 2 embedded figures, Latex, uses ws-p8-50x6-00. Invited talk
at COSMO99, to appear in the proceedings | null | 10.1142/9789812792129_0054 | null | hep-ph | null | I review the construction of the Exact Parity or Mirror Matter Model and
explain how it solves the solar and atmospheric neutrino problems. The
oscillation driven relic neutrino asymmetry amplification phenomenon is then
used to demonstrate the consistency of the model with Big Bang Nucleosynthesis.
| [
{
"created": "Tue, 1 Feb 2000 05:18:48 GMT",
"version": "v1"
}
] | 2016-11-03 | [
[
"Volkas",
"Raymond R",
""
]
] | I review the construction of the Exact Parity or Mirror Matter Model and explain how it solves the solar and atmospheric neutrino problems. The oscillation driven relic neutrino asymmetry amplification phenomenon is then used to demonstrate the consistency of the model with Big Bang Nucleosynthesis. |
1612.00032 | Srimoyee Sen | David B. Kaplan, Sanjay Reddy and Srimoyee Sen | Energy Conservation and the Chiral Magnetic Effect | We have corrected a sign error. But the main conclusions of the paper
remain unchanged | Phys. Rev. D 96, 016008 (2017) | 10.1103/PhysRevD.96.016008 | null | hep-ph astro-ph.HE nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We analyze the chiral magnetic effect in a homogeneous neutral plasma from
the point of view of energy conservation, and construct an effective potential
for the growth of maximally helical perturbations of the electromagnetic field.
We show that a negative curvature at the origin of the potential, indicating
instability of the plasma, is induced by a chiral asymmetry in electron Fermi
energy, as opposed to number density, while the potential grows at large field
value. It follows that the ground state for a plasma has zero magnetic
helicity; a nonzero electron mass will allow an excited state of a plasma with
nonzero helicity to relax to that ground state quickly. We conclude that a
chiral plasma instability triggered by weak interactions is not a viable
mechanism for explaining magnetic fields in stars except possibly when dynamics
drives the system far from equilibrium.
| [
{
"created": "Wed, 30 Nov 2016 21:11:34 GMT",
"version": "v1"
},
{
"created": "Mon, 29 May 2017 16:11:38 GMT",
"version": "v2"
}
] | 2017-07-19 | [
[
"Kaplan",
"David B.",
""
],
[
"Reddy",
"Sanjay",
""
],
[
"Sen",
"Srimoyee",
""
]
] | We analyze the chiral magnetic effect in a homogeneous neutral plasma from the point of view of energy conservation, and construct an effective potential for the growth of maximally helical perturbations of the electromagnetic field. We show that a negative curvature at the origin of the potential, indicating instability of the plasma, is induced by a chiral asymmetry in electron Fermi energy, as opposed to number density, while the potential grows at large field value. It follows that the ground state for a plasma has zero magnetic helicity; a nonzero electron mass will allow an excited state of a plasma with nonzero helicity to relax to that ground state quickly. We conclude that a chiral plasma instability triggered by weak interactions is not a viable mechanism for explaining magnetic fields in stars except possibly when dynamics drives the system far from equilibrium. |
hep-ph/9710490 | Lyndon Alvero | L. Alvero, J. C. Collins, M. Strikman and J. J. Whitmore (Penn. State
University, U.S.A.) | Probing small-x parton densities in proton- proton (-nucleus) collisions
in the very forward direction | 14 pages, LaTeX, 12 figures, uses revtex.sty | Phys. Rev. D 57, 4063 (1998) | 10.1103/PhysRevD.57.4063 | PSU/TH/190 | hep-ph | null | We present calculations of several pp scattering cross sections with
potential applications at the LHC. Significantly large rates for momentum
fraction, x, as low as 10^-7 are obtained, allowing for possible extraction of
quark and gluon densities in the proton and nuclei down to these small x values
provided a detector with good acceptance at maximal rapidities is used.
| [
{
"created": "Mon, 27 Oct 1997 22:19:47 GMT",
"version": "v1"
}
] | 2016-08-25 | [
[
"Alvero",
"L.",
"",
"Penn. State\n University, U.S.A."
],
[
"Collins",
"J. C.",
"",
"Penn. State\n University, U.S.A."
],
[
"Strikman",
"M.",
"",
"Penn. State\n University, U.S.A."
],
[
"Whitmore",
"J. J.",
"",
"Penn. State\n Universi... | We present calculations of several pp scattering cross sections with potential applications at the LHC. Significantly large rates for momentum fraction, x, as low as 10^-7 are obtained, allowing for possible extraction of quark and gluon densities in the proton and nuclei down to these small x values provided a detector with good acceptance at maximal rapidities is used. |
1006.2271 | Kazuya Yonekura | Tsutomu T. Yanagida, Kazuya Yonekura | A Conformal Gauge Mediation and Dark Matter with Only One Parameter | 17 pages | Phys.Lett.B693:281-286,2010 | 10.1016/j.physletb.2010.08.040 | UT-10-10, IPMU-10-0099 | hep-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | If the supersymmetry (SUSY) is a solution to the hierarchy problem, it is
puzzling that any SUSY particle has not been discovered yet. We show that there
is a low-scale conformal gauge mediation model which contains all necessary
ingredients, i.e. not only a SUSY-breaking dynamics and a gauge mediation
mechanism, but also a candidate for the dark matter. The model has only one
free parameter, that is, the mass for messengers. In this model, the dark
matter is provided by a composite particle in the SUSY-breaking sector, and the
observed value of the dark matter density uniquely fixes the mass of messengers
at the order of 10^2 TeV. Then, the sfermion and gaugino masses are fixed to be
of order 10^2~10^3 GEV without any arbitrariness, thus the SUSY particles are
expected not to be discovered at the Tevatron or LEP, while having a discovery
possibility at the LHC.
| [
{
"created": "Fri, 11 Jun 2010 11:47:25 GMT",
"version": "v1"
}
] | 2014-11-21 | [
[
"Yanagida",
"Tsutomu T.",
""
],
[
"Yonekura",
"Kazuya",
""
]
] | If the supersymmetry (SUSY) is a solution to the hierarchy problem, it is puzzling that any SUSY particle has not been discovered yet. We show that there is a low-scale conformal gauge mediation model which contains all necessary ingredients, i.e. not only a SUSY-breaking dynamics and a gauge mediation mechanism, but also a candidate for the dark matter. The model has only one free parameter, that is, the mass for messengers. In this model, the dark matter is provided by a composite particle in the SUSY-breaking sector, and the observed value of the dark matter density uniquely fixes the mass of messengers at the order of 10^2 TeV. Then, the sfermion and gaugino masses are fixed to be of order 10^2~10^3 GEV without any arbitrariness, thus the SUSY particles are expected not to be discovered at the Tevatron or LEP, while having a discovery possibility at the LHC. |
hep-ph/9503395 | Tetsuo Hatsuda | Tetsuo Hatsuda and Hiroyuki Shiomi | Vector Mesons in Nuclear Medium | 4 pages, Latex, talk at Quark Matter '95 | Nucl.Phys. A590 (1995) 545c-548c | 10.1016/0375-9474(95)00274-5 | null | hep-ph nucl-th | null | We summarize the current theoretical and experimental status of the spectral
change of the vector mesons in dense matter.
| [
{
"created": "Tue, 21 Mar 1995 06:58:59 GMT",
"version": "v1"
}
] | 2009-10-28 | [
[
"Hatsuda",
"Tetsuo",
""
],
[
"Shiomi",
"Hiroyuki",
""
]
] | We summarize the current theoretical and experimental status of the spectral change of the vector mesons in dense matter. |
2111.01820 | Alexander Penin A. | Tao Liu, Sneh Modi, Alexander A. Penin | Higgs Boson Production and Quark Scattering Amplitudes at High Energy
through the Next-to-Next-to-Leading Power in Quark Mass | 20 pages, 4 figures | null | 10.1007/JHEP02(2022)170 | ALBERTA-THY-32-21 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study the amplitudes of the quark scattering by an external
electromagnetic field and of the light quark mediated Higgs boson production
via gluon fusion in the high-energy limit. The asymptotic behavior of the quark
form factors is obtained in the double-logarithmic approximation to all orders
in strong coupling constant through ${\cal O}(m_q^3)$ in the small quark mass
expansion and the asymptotic formula is given in a closed analytic form. In the
case of the two-gluon Higgs boson form factor we obtain a complete analytic
result for the three-loop ${\cal O}(m_q^3)$ double-logarithmic term while the
all-order analysis is performed in the large-$N_c$ limit of QCD and for the
abelian gauge group. An estimate of the high-order high-power light quark mass
effect in the Higgs boson production and decay is given.
| [
{
"created": "Tue, 2 Nov 2021 18:04:43 GMT",
"version": "v1"
}
] | 2022-03-09 | [
[
"Liu",
"Tao",
""
],
[
"Modi",
"Sneh",
""
],
[
"Penin",
"Alexander A.",
""
]
] | We study the amplitudes of the quark scattering by an external electromagnetic field and of the light quark mediated Higgs boson production via gluon fusion in the high-energy limit. The asymptotic behavior of the quark form factors is obtained in the double-logarithmic approximation to all orders in strong coupling constant through ${\cal O}(m_q^3)$ in the small quark mass expansion and the asymptotic formula is given in a closed analytic form. In the case of the two-gluon Higgs boson form factor we obtain a complete analytic result for the three-loop ${\cal O}(m_q^3)$ double-logarithmic term while the all-order analysis is performed in the large-$N_c$ limit of QCD and for the abelian gauge group. An estimate of the high-order high-power light quark mass effect in the Higgs boson production and decay is given. |
1304.0711 | Rouzbeh Allahverdi | Rouzbeh Allahverdi and Bhaskar Dutta | Natural GeV Dark Matter and the Baryon-Dark Matter Coincidence Puzzle | 6 pages | null | 10.1103/PhysRevD.88.023525 | MIFPA-13-12 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present a simple extension of the standard model that gives rise to
baryogenesis a has a dark matter candidate of O(GeV) mass. A minimal set of new
fields required for baryogenesis includes two O(TeV) colored scalars and a
singlet fermion. The fermion also becomes a viable dark matter candidate when
its is nearly degenerate in mass with the proton. Dark matter and baryon
asymmetry are produced form the decay of heavy scalars, which can lead to a
natural explanation of the baryon-dark matter coincidence problem. The dark
matter candidate escapes direct and indirect detection, but can be probed at
the LHC. The supersymmetric extension of this model is straightforward and
leads to a multi-component dark matter scenario, which improves the direct and
indirect detection prospects.
| [
{
"created": "Tue, 2 Apr 2013 17:49:21 GMT",
"version": "v1"
}
] | 2013-08-09 | [
[
"Allahverdi",
"Rouzbeh",
""
],
[
"Dutta",
"Bhaskar",
""
]
] | We present a simple extension of the standard model that gives rise to baryogenesis a has a dark matter candidate of O(GeV) mass. A minimal set of new fields required for baryogenesis includes two O(TeV) colored scalars and a singlet fermion. The fermion also becomes a viable dark matter candidate when its is nearly degenerate in mass with the proton. Dark matter and baryon asymmetry are produced form the decay of heavy scalars, which can lead to a natural explanation of the baryon-dark matter coincidence problem. The dark matter candidate escapes direct and indirect detection, but can be probed at the LHC. The supersymmetric extension of this model is straightforward and leads to a multi-component dark matter scenario, which improves the direct and indirect detection prospects. |
2101.07421 | Alexander Ritter | Alexander C. Ritter and Raymond R. Volkas | Implementing Asymmetric Dark Matter and Dark Electroweak Baryogenesis in
a Mirror Two-Higgs-Doublet Model | 58 pages, 6 figures. Matches published version. New content added,
primarily in Sec.IV.A | Phys. Rev. D 104, 035032 (2021) | 10.1103/PhysRevD.104.035032 | null | hep-ph | http://creativecommons.org/licenses/by/4.0/ | Models of asymmetric dark matter (ADM) seek to explain the apparent
coincidence between the present-day mass densities of visible and dark matter,
$\Omega_{\mathrm{DM}} \simeq 5\Omega_{\mathrm{VM}}$. However, most ADM models
only relate the number densities of visible and dark matter without motivating
the similar particle masses. We expand upon a recent work that obtained a
natural mass relationship in a mirror matter ADM model with two Higgs doublets
in each sector, by looking to implement dark electroweak baryogenesis as the
means of asymmetry generation. We explore two aspects of the mechanism: the
nature of the dark electroweak phase transition, and the transfer of particle
asymmetries between the sectors by the use of portal interactions. We find that
both aspects can be implemented successfully for various regions of the
parameter space. We also analyse one portal interaction -- the neutron portal
-- in greater detail, in order to satisfy the observational constraints on dark
radiation.
| [
{
"created": "Tue, 19 Jan 2021 02:31:37 GMT",
"version": "v1"
},
{
"created": "Wed, 1 Sep 2021 03:33:35 GMT",
"version": "v2"
}
] | 2021-09-02 | [
[
"Ritter",
"Alexander C.",
""
],
[
"Volkas",
"Raymond R.",
""
]
] | Models of asymmetric dark matter (ADM) seek to explain the apparent coincidence between the present-day mass densities of visible and dark matter, $\Omega_{\mathrm{DM}} \simeq 5\Omega_{\mathrm{VM}}$. However, most ADM models only relate the number densities of visible and dark matter without motivating the similar particle masses. We expand upon a recent work that obtained a natural mass relationship in a mirror matter ADM model with two Higgs doublets in each sector, by looking to implement dark electroweak baryogenesis as the means of asymmetry generation. We explore two aspects of the mechanism: the nature of the dark electroweak phase transition, and the transfer of particle asymmetries between the sectors by the use of portal interactions. We find that both aspects can be implemented successfully for various regions of the parameter space. We also analyse one portal interaction -- the neutron portal -- in greater detail, in order to satisfy the observational constraints on dark radiation. |
hep-ph/0311113 | Abbas Nehme | A. Nehme | Isospin Breaking in $K_{\ell 4}$ Decays of the Neutral Kaon | 62 pages, LaTeX, 5 postscript figures, 1 table | Nucl.Phys. B682 (2004) 289-346 | 10.1016/j.nuclphysb.2004.01.017 | CPT-2003/P.4509 | hep-ph | null | In the presence of photons, the neutral $K_{\ell 4}$ decay,
$K^0\to\pi^0\pi^-\ell^+\nu_\ell$, can be parameterized in terms of three
vectorial, one anomalous, and one tensorial form factors. We present here
analytic expressions of two vectorial form factors, $f$ and $g$, calculated at
one-loop level in the framework of chiral perturbation theory based on the
effective Lagrangian including mesons, photons, and leptons. These expressions
may then be used to disentangle the Isospin breaking part from the measured
form factors and hence improve the accuracy in the determination of $\pi\pi$
scattering parameters from $K_{\ell 4}$ experiments.
| [
{
"created": "Mon, 10 Nov 2003 13:55:10 GMT",
"version": "v1"
}
] | 2009-11-10 | [
[
"Nehme",
"A.",
""
]
] | In the presence of photons, the neutral $K_{\ell 4}$ decay, $K^0\to\pi^0\pi^-\ell^+\nu_\ell$, can be parameterized in terms of three vectorial, one anomalous, and one tensorial form factors. We present here analytic expressions of two vectorial form factors, $f$ and $g$, calculated at one-loop level in the framework of chiral perturbation theory based on the effective Lagrangian including mesons, photons, and leptons. These expressions may then be used to disentangle the Isospin breaking part from the measured form factors and hence improve the accuracy in the determination of $\pi\pi$ scattering parameters from $K_{\ell 4}$ experiments. |
hep-ph/0501090 | Thomas D. Cohen | Thomas D. COhen | Excited Baryons in Large $N_c$ QCD | Talk at "Baryons 04", Palaiseau, October 2004 | Nucl.Phys. A755 (2005) 40-48 | 10.1016/j.nuclphysa.2005.03.022 | null | hep-ph | null | This talk reviews recent developments in the use of large $N_c$ QCD in the
description of baryonic resonances. The emphasis is on the model-independent
nature of the approach. Key issues discussed include the spin-flavor symmetry
which emerges at large $N_c$ and the direct use of scattering observables. The
connection to quark model approaches is stressed.
| [
{
"created": "Tue, 11 Jan 2005 19:17:05 GMT",
"version": "v1"
}
] | 2015-06-25 | [
[
"COhen",
"Thomas D.",
""
]
] | This talk reviews recent developments in the use of large $N_c$ QCD in the description of baryonic resonances. The emphasis is on the model-independent nature of the approach. Key issues discussed include the spin-flavor symmetry which emerges at large $N_c$ and the direct use of scattering observables. The connection to quark model approaches is stressed. |
hep-ph/9710249 | Chris Michael | Chris Michael | Hadronic Physics from the Lattice | to appear in Proceedings of the NATO Advanced Study Institute on
Confinement, Duality and Non-Perturbative Aspects of QCD. June 23 - July 4,
1997; 19 pages, Latex, 6 postscript figures | null | null | LTH 411 | hep-ph hep-lat | null | Topics covered in this review are the lattice gauge theory approach to the
evaluation of non-perturbative hadronic interactions from first principles,
particularly applications to glueballs, inter-quark potentials, the running
coupling constant and hybrid mesons. Also discussed are the limitations of the
quenched approximation.
| [
{
"created": "Mon, 6 Oct 1997 11:39:44 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Michael",
"Chris",
""
]
] | Topics covered in this review are the lattice gauge theory approach to the evaluation of non-perturbative hadronic interactions from first principles, particularly applications to glueballs, inter-quark potentials, the running coupling constant and hybrid mesons. Also discussed are the limitations of the quenched approximation. |
2105.04050 | Timofey Uglov | P. Pakhlov and T. Uglov | On measurement of photon polarization in radiative penguin $B$ decays to
baryons | 4 pages, 2 figures | European Physical Journal C 81 (2021) 759 | 10.1140/epjc/s10052-021-09528-4 | null | hep-ph hep-ex | http://creativecommons.org/licenses/by/4.0/ | A measurement of the photon polarization in radiative penguin $B$ decays
provides a test of the Standard Model and a probe for New Physics, that can
lead to a deviation from the Standard Model prediction of left-handed photons
in $b\to s \gamma$. We propose a new method to measure the photon polarization
using the baryonic decay $B^- \to \Lambda\bar{p} \gamma$. The $P$-violating
$\Lambda$-hyperon decay allows a measurement of the $\Lambda$ helicity to be
performed, which can be uniquely related to the photon polarization in a
model-independent way. The $B^- \to \Lambda\bar{p} \gamma$ decay was recently
measured to have a large branching fraction providing a possibility to get
meaningful results with the data already available at LHC and B-factory
experiments. An increase of the $B$-meson sample at high luminosity LHC
experiments and Belle II should provide a really stringent test by using this
method already in the near future.
| [
{
"created": "Sun, 9 May 2021 23:20:50 GMT",
"version": "v1"
},
{
"created": "Wed, 8 Sep 2021 16:55:12 GMT",
"version": "v2"
}
] | 2021-09-09 | [
[
"Pakhlov",
"P.",
""
],
[
"Uglov",
"T.",
""
]
] | A measurement of the photon polarization in radiative penguin $B$ decays provides a test of the Standard Model and a probe for New Physics, that can lead to a deviation from the Standard Model prediction of left-handed photons in $b\to s \gamma$. We propose a new method to measure the photon polarization using the baryonic decay $B^- \to \Lambda\bar{p} \gamma$. The $P$-violating $\Lambda$-hyperon decay allows a measurement of the $\Lambda$ helicity to be performed, which can be uniquely related to the photon polarization in a model-independent way. The $B^- \to \Lambda\bar{p} \gamma$ decay was recently measured to have a large branching fraction providing a possibility to get meaningful results with the data already available at LHC and B-factory experiments. An increase of the $B$-meson sample at high luminosity LHC experiments and Belle II should provide a really stringent test by using this method already in the near future. |
0905.0419 | Lisheng Geng | L. S. Geng, E. Oset, R. Molina, and D. Nicmorus | Dynamically generated resonances from vector meson-vector meson
interaction based on a hidden-gauge unitary approach | 7 pages, 1 figure, 4 tables; presented at the International Workshop
on Effective Field Theories: from the Pion to the Upsilon, 2-6 February 2009,
Valencia, Spain | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present a recent study of vector meson-vector meson interaction using a
unitary approach based on the hidden-gauge Lagrangians. We find that 11 states
get dynamically generated, corresponding to poles of the scattering matrices on
the second Riemann sheet. Five of them are associated to the $f_0(1370)$,
$f_0(1710)$, $f_2(1270)$, $f_2'(1525)$, and $K^*_2(1430)$, by comparing the
mass, width, and decay pattern of these states with those of their experimental
counterparts. Six others with the quantum numbers of $h_1$, $a_0$, $b_1$,
$a_2$, $K^*_0$, and $K_1$ can not be clearly identified with any experimentally
observed resonances and should be taken as predictions to be tested by future
experiments.
| [
{
"created": "Mon, 4 May 2009 16:41:34 GMT",
"version": "v1"
}
] | 2009-05-05 | [
[
"Geng",
"L. S.",
""
],
[
"Oset",
"E.",
""
],
[
"Molina",
"R.",
""
],
[
"Nicmorus",
"D.",
""
]
] | We present a recent study of vector meson-vector meson interaction using a unitary approach based on the hidden-gauge Lagrangians. We find that 11 states get dynamically generated, corresponding to poles of the scattering matrices on the second Riemann sheet. Five of them are associated to the $f_0(1370)$, $f_0(1710)$, $f_2(1270)$, $f_2'(1525)$, and $K^*_2(1430)$, by comparing the mass, width, and decay pattern of these states with those of their experimental counterparts. Six others with the quantum numbers of $h_1$, $a_0$, $b_1$, $a_2$, $K^*_0$, and $K_1$ can not be clearly identified with any experimentally observed resonances and should be taken as predictions to be tested by future experiments. |
1508.00308 | Harleen Dahiya Dr. | Aarti Girdhar, Harleen Dahiya and Monika Randhawa | Magnetic moments of $J^P=\frac{3}{2}^+$ decuplet baryons using effective
quark masses in chiral constituent quark model | 21 pages. To appear in Phys. Rev. D. arXiv admin note: text overlap
with arXiv:1505.03304 | Phys.Rev. D92 (2015) 3, 033012 | 10.1103/PhysRevD.92.033012 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The magnetic moments of $J^P=\frac{3}{2}^+$ decuplet baryons have been
calculated in the chiral constituent quark model ($\chi$CQM) with explicit
results for the contribution coming from the valence quark polarizations, sea
quark polarizations, and their orbital angular momentum. Since the
$J^P=\frac{3}{2}^+$ decuplet baryons have short lifetimes, the experimental
information about them is limited. The $\chi$CQM has important implications for
chiral symmetry breaking as well as SU(3) symmetry breaking since it works in
the region between the QCD confinement scale and the chiral symmetry breaking
scale. The predictions in the model not only give a satisfactory fit when
compared with the experimental data but also show improvement over the other
models. The effect of the confinement on quark masses has also been discussed
in detail and the results of $\chi$CQM are found to improve further with the
inclusion of effective quark masses.
| [
{
"created": "Mon, 3 Aug 2015 03:34:35 GMT",
"version": "v1"
}
] | 2015-09-30 | [
[
"Girdhar",
"Aarti",
""
],
[
"Dahiya",
"Harleen",
""
],
[
"Randhawa",
"Monika",
""
]
] | The magnetic moments of $J^P=\frac{3}{2}^+$ decuplet baryons have been calculated in the chiral constituent quark model ($\chi$CQM) with explicit results for the contribution coming from the valence quark polarizations, sea quark polarizations, and their orbital angular momentum. Since the $J^P=\frac{3}{2}^+$ decuplet baryons have short lifetimes, the experimental information about them is limited. The $\chi$CQM has important implications for chiral symmetry breaking as well as SU(3) symmetry breaking since it works in the region between the QCD confinement scale and the chiral symmetry breaking scale. The predictions in the model not only give a satisfactory fit when compared with the experimental data but also show improvement over the other models. The effect of the confinement on quark masses has also been discussed in detail and the results of $\chi$CQM are found to improve further with the inclusion of effective quark masses. |
hep-ph/0305029 | Cosmin Macesanu | C. Macesanu, A. Mitov and S. Nandi | Gravity and Matter in Extra Dimensions | 21 pages, 6 figures, Latex | Phys.Rev. D68 (2003) 084008 | 10.1103/PhysRevD.68.084008 | null | hep-ph | null | In this paper, we derive from the viewpoint of the effective 4D theory the
interaction terms between linearized gravity propagating in N>= 2 large extra
dimensions and matter propagating into one extra dimension. This generalizes
known results for the interactions between gravity and 4D matter in ADD-type
models. Although we assume that matter is described by an Universal Extra
Dimensions (UED) scenario (with all fields propagating into the fifth
dimension), we present our results in a general form that can be easily adapted
to various other scenarios of matter distribution. We then apply our results to
the UED model on a fat brane and consider some phenomenological applications.
Among these are the computation of the gravitational decay widths of the matter
KK excitations and the effect the width of the brane has on the interactions of
gravity with Standard Model particles. We also estimate the cross-section for
producing single KK excitations at colliders through KK number-violating
gravitational interaction.
| [
{
"created": "Fri, 2 May 2003 22:53:39 GMT",
"version": "v1"
}
] | 2009-11-10 | [
[
"Macesanu",
"C.",
""
],
[
"Mitov",
"A.",
""
],
[
"Nandi",
"S.",
""
]
] | In this paper, we derive from the viewpoint of the effective 4D theory the interaction terms between linearized gravity propagating in N>= 2 large extra dimensions and matter propagating into one extra dimension. This generalizes known results for the interactions between gravity and 4D matter in ADD-type models. Although we assume that matter is described by an Universal Extra Dimensions (UED) scenario (with all fields propagating into the fifth dimension), we present our results in a general form that can be easily adapted to various other scenarios of matter distribution. We then apply our results to the UED model on a fat brane and consider some phenomenological applications. Among these are the computation of the gravitational decay widths of the matter KK excitations and the effect the width of the brane has on the interactions of gravity with Standard Model particles. We also estimate the cross-section for producing single KK excitations at colliders through KK number-violating gravitational interaction. |
0811.3537 | John F. Gunion | Radovan Dermisek and John F. Gunion | Many Light Higgs Bosons in the NMSSM | 15 pages, 47 figures | Phys.Rev.D79:055014,2009 | 10.1103/PhysRevD.79.055014 | null | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The next-to-minimal supersymmetric model with a light doublet-like
CP-odd Higgs boson and small $\tan \beta$ can satisfy all experimental limits
on Higgs bosons even with light superpartners. In these scenarios, the two
lightest CP-even Higgs bosons, $\hi$ and $\hii$, and the charged Higgs boson,
$\hp$, can all be light enough to be produced at LEP and yet have decays that
have not been looked for or are poorly constrained by existing collider
experiments. The channel $\hi\to \ai\ai$ (where $\ai$ is the lightest CP-odd
boson and has mass below $2m_b$) with $\ai\to \tau^+\tau^-$ or $2j$ is still
awaiting LEP constraints for $\mhi>86\gev$ or $82\gev$, respectively. LEP data
may also contain $\epem\to \hii\ai$ events where $\hii\to Z\ai$ is the dominant
decay, a channel that was never examined. Decays of the charged Higgs bosons
are often dominated by $H^\pm \to W^{\pm (\star)} \ai$ with $\ai \to gg,c \bar
c, \tau^+ \tau^-$. This is a channel that has so far been ignored in the search
for $t\to \hp b$ decays at the Tevatron. A specialized analysis might reveal a
signal. The light $\ai$ might be within the reach of $B$ factories via
$\Upsilon\to \gamma \ai$ decays. We study typical mass ranges and branching
ratios of Higgs bosons in this scenario and compare these scenarios where the
$\ai$ has a large doublet component to the more general scenarios with
arbitrary singlet component for the $\ai$.
| [
{
"created": "Fri, 21 Nov 2008 09:29:54 GMT",
"version": "v1"
}
] | 2009-03-24 | [
[
"Dermisek",
"Radovan",
""
],
[
"Gunion",
"John F.",
""
]
] | The next-to-minimal supersymmetric model with a light doublet-like CP-odd Higgs boson and small $\tan \beta$ can satisfy all experimental limits on Higgs bosons even with light superpartners. In these scenarios, the two lightest CP-even Higgs bosons, $\hi$ and $\hii$, and the charged Higgs boson, $\hp$, can all be light enough to be produced at LEP and yet have decays that have not been looked for or are poorly constrained by existing collider experiments. The channel $\hi\to \ai\ai$ (where $\ai$ is the lightest CP-odd boson and has mass below $2m_b$) with $\ai\to \tau^+\tau^-$ or $2j$ is still awaiting LEP constraints for $\mhi>86\gev$ or $82\gev$, respectively. LEP data may also contain $\epem\to \hii\ai$ events where $\hii\to Z\ai$ is the dominant decay, a channel that was never examined. Decays of the charged Higgs bosons are often dominated by $H^\pm \to W^{\pm (\star)} \ai$ with $\ai \to gg,c \bar c, \tau^+ \tau^-$. This is a channel that has so far been ignored in the search for $t\to \hp b$ decays at the Tevatron. A specialized analysis might reveal a signal. The light $\ai$ might be within the reach of $B$ factories via $\Upsilon\to \gamma \ai$ decays. We study typical mass ranges and branching ratios of Higgs bosons in this scenario and compare these scenarios where the $\ai$ has a large doublet component to the more general scenarios with arbitrary singlet component for the $\ai$. |
hep-ph/9207216 | null | Mirjam Cveti\v{c} and Paul Langacker | $V'Z$ and $V'W$ Production as Tests of Heavy Gauge Boson Couplings at
Future Hadron Colliders | 27 pages, 14 figures (not included), PHYZZX and TABLES, UPR-0514T | Phys.Rev.D46:4943,1992; Erratum-ibid.D48:4484,1993;
Phys.Rev.D48:4484,1993 | 10.1103/PhysRevD.46.4943 10.1103/PhysRevD.48.4484 | null | hep-ph | null | We point out that the production cross section of $pp\to V'V$, with
$V'=W',Z'$ and $V=W,Z$ is a useful diagnostic of $V'$ gauge couplings at future
hadron colliders. For $M_{Z'}\simeq1$ TeV it would allow determination of
combinations of $Z'$ gauge couplings to the quarks to around 10 percent. An
analysis of the extraction of gauge couplings from the complementary tests:
forward-backward asymmetry, rare decays $pp\to V'\to f_1{\bar f_2}V$, and the
production cross section $pp\to V'V$ is given in a model-independent framework.
Four ratios of charges are needed to characterize a general gauge theory with
an additional family-independent $U_1'$ factor. We show that there are four
functions of these ratios observable at hadron colliders, but for projected SSC
and LHC luminosities only two combinations can be extracted. These yield a
significant discrimination between interesting GUT-motivated models. Clean
tests of whether a new $W'$ couples to right-handed currents, of the ratio
$g_R/g_L$ of gauge couplings, and of the non-abelian vertex in left-right
symmetric models are described.
| [
{
"created": "Sun, 5 Jul 1992 20:11:03 GMT",
"version": "v1"
}
] | 2014-11-17 | [
[
"Cvetič",
"Mirjam",
""
],
[
"Langacker",
"Paul",
""
]
] | We point out that the production cross section of $pp\to V'V$, with $V'=W',Z'$ and $V=W,Z$ is a useful diagnostic of $V'$ gauge couplings at future hadron colliders. For $M_{Z'}\simeq1$ TeV it would allow determination of combinations of $Z'$ gauge couplings to the quarks to around 10 percent. An analysis of the extraction of gauge couplings from the complementary tests: forward-backward asymmetry, rare decays $pp\to V'\to f_1{\bar f_2}V$, and the production cross section $pp\to V'V$ is given in a model-independent framework. Four ratios of charges are needed to characterize a general gauge theory with an additional family-independent $U_1'$ factor. We show that there are four functions of these ratios observable at hadron colliders, but for projected SSC and LHC luminosities only two combinations can be extracted. These yield a significant discrimination between interesting GUT-motivated models. Clean tests of whether a new $W'$ couples to right-handed currents, of the ratio $g_R/g_L$ of gauge couplings, and of the non-abelian vertex in left-right symmetric models are described. |
1111.6330 | Xiao-Gang He | Gang Guo, Xiao-Gang He | Dispersion Relations Explaining OPERA Data From Deformed Lorentz
Transformation | 8 pages, 2 figures. Several typos corrected and some references added | null | 10.1142/S2010194512005909 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | OPERA collaboration has reported evidence of superluminal phenomenon for
neutrinos. One of the possible ways to explain the superluminality is to have
Lorentz symmetry violated. It has been shown that dispersion relations put
forwards has the problem of physics laws vary in different inertial frames
leading to conflicting results on Cherenkov-like radiation, pion decay and high
energy neutrino cosmic ray. For theories with deformed Lorentz symmetry, by
modifying conservation laws corresponding to energy and momentum in the usual
Lorentz invariant theory, it is possible to have superluminal effect and at the
same time avoid to have conflicts encountered in Lorentz violating theories. We
study dispersion relations from deformed Lorentz symmetry. We find that it is
possible to have dispersion relations which can be consistent with data on
neutrinos. We show that once the superluminality $\delta v$ as a function of
energy is known the corresponding dispersion relation in the deformed Lorentz
symmetry can be determined.
| [
{
"created": "Mon, 28 Nov 2011 02:25:03 GMT",
"version": "v1"
},
{
"created": "Fri, 2 Dec 2011 01:17:50 GMT",
"version": "v2"
}
] | 2015-06-03 | [
[
"Guo",
"Gang",
""
],
[
"He",
"Xiao-Gang",
""
]
] | OPERA collaboration has reported evidence of superluminal phenomenon for neutrinos. One of the possible ways to explain the superluminality is to have Lorentz symmetry violated. It has been shown that dispersion relations put forwards has the problem of physics laws vary in different inertial frames leading to conflicting results on Cherenkov-like radiation, pion decay and high energy neutrino cosmic ray. For theories with deformed Lorentz symmetry, by modifying conservation laws corresponding to energy and momentum in the usual Lorentz invariant theory, it is possible to have superluminal effect and at the same time avoid to have conflicts encountered in Lorentz violating theories. We study dispersion relations from deformed Lorentz symmetry. We find that it is possible to have dispersion relations which can be consistent with data on neutrinos. We show that once the superluminality $\delta v$ as a function of energy is known the corresponding dispersion relation in the deformed Lorentz symmetry can be determined. |
hep-ph/0211298 | Sergei Chekanov | S. V. Chekanov (ANL) | Jet algorithms: a minireview | 8 pages, 2 eps figures, to be published in the proceedings of the
14th Topical Conference on Hadron Collider Physics, (28 Sep - 4 Oct 2002)
Karlsruhe, Germany | null | null | ANL-HEP-CP-02-103 | hep-ph | null | Many jet algorithms have been proposed in the past to study the hadronic
final state in E+E-, EP and PP collisions. Here we review some of the most
popular, mainly concentrating on the jet algorithms used at HERA and TEVATRON.
| [
{
"created": "Tue, 19 Nov 2002 10:44:57 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Chekanov",
"S. V.",
"",
"ANL"
]
] | Many jet algorithms have been proposed in the past to study the hadronic final state in E+E-, EP and PP collisions. Here we review some of the most popular, mainly concentrating on the jet algorithms used at HERA and TEVATRON. |
2008.08940 | Shihwen Hor | Koichi Hamaguchi, Shihwen Hor, and Natsumi Nagata | R-Symmetric Flipped SU(5) | 30 pages, 2 figures | null | 10.1007/JHEP11(2020)140 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We construct a supersymmetric flipped SU(5) grand unified model that
possesses an $R$ symmetry. This $R$ symmetry forbids dangerous
non-renormalizable operators suppressed by a cut-off scale up to sufficiently
large mass dimensions so that the SU(5)-breaking Higgs field develops a vacuum
expectation value of the order of the unification scale along the $F$- and
$D$-flat directions, with the help of the supersymmetry-breaking effect. The
mass terms of the Higgs fields are also forbidden by the $R$ symmetry, with
which the doublet-triplet splitting problem is solved with the missing partner
mechanism. The masses of right-handed neutrinos are generated by
non-renormalizable operators, which then yield a light neutrino mass spectrum
and mixing through the seesaw mechanism that are consistent with neutrino
oscillation data. This model predicts one of the color-triplet Higgs multiplets
to lie at an intermediate scale, and its mass is found to be constrained by
proton decay experiments to be $\gtrsim 5 \times 10^{11}$ GeV. If it is
$\lesssim 10^{12}$ GeV, future proton decay experiments at Hyper-Kamiokande can
test our model in the $p \to \pi^0 \mu^+$ and $p \to K^0 \mu^+$ decay modes, in
contrast to ordinary grand unified models where $p \to \pi^0 e^+ $ or $p \to
K^+ \bar{\nu}$ is the dominant decay mode. This characteristic prediction for
the proton decay branches enables us to distinguish our model from other
scenarios.
| [
{
"created": "Thu, 20 Aug 2020 12:49:02 GMT",
"version": "v1"
}
] | 2020-12-30 | [
[
"Hamaguchi",
"Koichi",
""
],
[
"Hor",
"Shihwen",
""
],
[
"Nagata",
"Natsumi",
""
]
] | We construct a supersymmetric flipped SU(5) grand unified model that possesses an $R$ symmetry. This $R$ symmetry forbids dangerous non-renormalizable operators suppressed by a cut-off scale up to sufficiently large mass dimensions so that the SU(5)-breaking Higgs field develops a vacuum expectation value of the order of the unification scale along the $F$- and $D$-flat directions, with the help of the supersymmetry-breaking effect. The mass terms of the Higgs fields are also forbidden by the $R$ symmetry, with which the doublet-triplet splitting problem is solved with the missing partner mechanism. The masses of right-handed neutrinos are generated by non-renormalizable operators, which then yield a light neutrino mass spectrum and mixing through the seesaw mechanism that are consistent with neutrino oscillation data. This model predicts one of the color-triplet Higgs multiplets to lie at an intermediate scale, and its mass is found to be constrained by proton decay experiments to be $\gtrsim 5 \times 10^{11}$ GeV. If it is $\lesssim 10^{12}$ GeV, future proton decay experiments at Hyper-Kamiokande can test our model in the $p \to \pi^0 \mu^+$ and $p \to K^0 \mu^+$ decay modes, in contrast to ordinary grand unified models where $p \to \pi^0 e^+ $ or $p \to K^+ \bar{\nu}$ is the dominant decay mode. This characteristic prediction for the proton decay branches enables us to distinguish our model from other scenarios. |
hep-ph/9708454 | null | T.G. Steele, J.C. Breckenridge, M. Benmerrouche, V. Elias, A.H.
Fariborz | QCD Sum Rules and the Pi(1300) Resonance | latex, 8 pages, 5 figures | Nucl.Phys. A624 (1997) 517-526 | 10.1016/S0375-9474(97)00472-7 | null | hep-ph | null | Global fits to the shape of the first QCD Laplace sum rule exhibiting
sensitivity to pion-resonance [$\Pi (1300)$] parameters are performed, leading
to predictions for the pion-resonance mass and decay constant. Two scenarios
are considered which differ only in their treatment of the dimension-six quark
condensate $< O_6>$. The first scenario assumes an effective scale for $< O_6>$
from other sum-rule applications which is assumed to be independent of the
physical value of the quark mass, while the second scenario requires
self-consistency between the value of $< O_6>$ and the current algebra
constraint $2m< \bar q q>=-f_\pi^2m_\pi^2$. Predictions of the pion-resonance
mass $M_\pi$ and decay constant $F_\pi$ are obtained in these two scenarios. A
byproduct of this analysis is a prediction of the renormalization-group
invariant quark mass $(\hat m_u+\hat m_d)/2$.
| [
{
"created": "Mon, 25 Aug 1997 20:01:42 GMT",
"version": "v1"
}
] | 2009-10-30 | [
[
"Steele",
"T. G.",
""
],
[
"Breckenridge",
"J. C.",
""
],
[
"Benmerrouche",
"M.",
""
],
[
"Elias",
"V.",
""
],
[
"Fariborz",
"A. H.",
""
]
] | Global fits to the shape of the first QCD Laplace sum rule exhibiting sensitivity to pion-resonance [$\Pi (1300)$] parameters are performed, leading to predictions for the pion-resonance mass and decay constant. Two scenarios are considered which differ only in their treatment of the dimension-six quark condensate $< O_6>$. The first scenario assumes an effective scale for $< O_6>$ from other sum-rule applications which is assumed to be independent of the physical value of the quark mass, while the second scenario requires self-consistency between the value of $< O_6>$ and the current algebra constraint $2m< \bar q q>=-f_\pi^2m_\pi^2$. Predictions of the pion-resonance mass $M_\pi$ and decay constant $F_\pi$ are obtained in these two scenarios. A byproduct of this analysis is a prediction of the renormalization-group invariant quark mass $(\hat m_u+\hat m_d)/2$. |
2102.07082 | Manu Kurian | Jai Prakash, Manu Kurian, Santosh K. Das, Vinod Chandra | Heavy quark transport in an anisotropic hot QCD medium: Collisional and
Radiative processes | 11 pages, 4 figures, Version accepted for publication in Physical
Review D | Phys. Rev. D 103, 094009 (2021) | 10.1103/PhysRevD.103.094009 | null | hep-ph nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The impact of momentum anisotropy on the heavy quark transport coefficients
due to collisional and radiative processes in the QCD medium has been studied
within the ambit of kinetic theory. Anisotropic aspects (momentum) are
incorporated into the heavy quark dynamics through the non-equilibrium momentum
distribution function of quarks, antiquarks, and gluons. These non-equilibrium
distribution functions that encode the physics of momentum anisotropy and
turbulent chromo-fields have been obtained by solving the ensemble-averaged
diffusive Vlasov-Boltzmann equation. The momentum dependence of heavy quark
transport coefficients in the medium is seen to be sensitive to the strength of
the anisotropy for both collisional and radiative processes. In addition, the
collisional and radiative energy loss of the heavy quark in the anisotropic hot
QCD medium have been analyzed. The effects of anisotropy on the drag and
diffusion coefficients are observed to have a visible impact on the nuclear
suppression factor both at the RHIC and LHC.
| [
{
"created": "Sun, 14 Feb 2021 06:29:35 GMT",
"version": "v1"
},
{
"created": "Sat, 1 May 2021 09:22:34 GMT",
"version": "v2"
}
] | 2021-05-14 | [
[
"Prakash",
"Jai",
""
],
[
"Kurian",
"Manu",
""
],
[
"Das",
"Santosh K.",
""
],
[
"Chandra",
"Vinod",
""
]
] | The impact of momentum anisotropy on the heavy quark transport coefficients due to collisional and radiative processes in the QCD medium has been studied within the ambit of kinetic theory. Anisotropic aspects (momentum) are incorporated into the heavy quark dynamics through the non-equilibrium momentum distribution function of quarks, antiquarks, and gluons. These non-equilibrium distribution functions that encode the physics of momentum anisotropy and turbulent chromo-fields have been obtained by solving the ensemble-averaged diffusive Vlasov-Boltzmann equation. The momentum dependence of heavy quark transport coefficients in the medium is seen to be sensitive to the strength of the anisotropy for both collisional and radiative processes. In addition, the collisional and radiative energy loss of the heavy quark in the anisotropic hot QCD medium have been analyzed. The effects of anisotropy on the drag and diffusion coefficients are observed to have a visible impact on the nuclear suppression factor both at the RHIC and LHC. |
hep-ph/9412321 | Vladimir Pascalutsa | V. Pascalutsa | On the interaction of spin 3/2 particles | 4 pages, latex, no figures | null | null | null | hep-ph | null | Lagrangian of a massive particle with spin 3/2 is considered in the
Rarita-Schwinger formalism. We discuss implications of the contact- and the
gauge-transformation on the physical content of free and interacting theories.
It is shown that the ``contact-invariance'' is trivial and has no physical
relevance. The requirement of the gauge-invariance of the free lagrangian fixes
the off-shell lower-spin content of the spin-3/2 field. The gauge-invariance of
the interaction lagrangian insures that these lower-spin components are not
coupled, and (probably always) leads to theories consistent with local
causality.
| [
{
"created": "Mon, 19 Dec 1994 21:39:36 GMT",
"version": "v1"
},
{
"created": "Tue, 20 Dec 1994 06:14:05 GMT",
"version": "v2"
},
{
"created": "Tue, 9 Jul 1996 16:14:40 GMT",
"version": "v3"
}
] | 2016-09-01 | [
[
"Pascalutsa",
"V.",
""
]
] | Lagrangian of a massive particle with spin 3/2 is considered in the Rarita-Schwinger formalism. We discuss implications of the contact- and the gauge-transformation on the physical content of free and interacting theories. It is shown that the ``contact-invariance'' is trivial and has no physical relevance. The requirement of the gauge-invariance of the free lagrangian fixes the off-shell lower-spin content of the spin-3/2 field. The gauge-invariance of the interaction lagrangian insures that these lower-spin components are not coupled, and (probably always) leads to theories consistent with local causality. |
1006.2431 | Guy F. de T\'eramond | Guy F. de Teramond and Stanley J. Brodsky | Gauge/Gravity Duality and Hadron Physics at the Light-Front | Invited talk presented by GdT at XI Hadron Physics, Maresias Beach,
Sao Paulo, Brazil, 21-26 March 2010 | AIP Conf.Proc.1296:128-139,2010 | 10.1063/1.3523157 | SLAC-PUB-14154, CP3-Origins-2010-22 | hep-ph hep-lat hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We discuss some remarkable features of the light-front holographic mapping of
classical gravity in anti-de Sitter space modified by a confining dilaton
background. In particular, we show that a positive-sign dilaton solution
$\exp(+\kappa^2 z^2)$ has better chances to describe the correct hadronic
phenomenology than the negative solution $\exp{(- \kappa^2 z^2)}$ extensively
studied in the literature. We also show that the use of twist-scaling
dimensions, instead of canonical dimensions, is required to give a good
description of the spectrum and form factors of hadrons. Another key element is
the explicit connection of AdS modes of total angular momentum $J$ with the
internal structure of hadrons and the proper identification of the orbital
angular momentum of the constituents.
| [
{
"created": "Sat, 12 Jun 2010 04:37:48 GMT",
"version": "v1"
},
{
"created": "Tue, 22 Jun 2010 17:25:21 GMT",
"version": "v2"
}
] | 2010-12-15 | [
[
"de Teramond",
"Guy F.",
""
],
[
"Brodsky",
"Stanley J.",
""
]
] | We discuss some remarkable features of the light-front holographic mapping of classical gravity in anti-de Sitter space modified by a confining dilaton background. In particular, we show that a positive-sign dilaton solution $\exp(+\kappa^2 z^2)$ has better chances to describe the correct hadronic phenomenology than the negative solution $\exp{(- \kappa^2 z^2)}$ extensively studied in the literature. We also show that the use of twist-scaling dimensions, instead of canonical dimensions, is required to give a good description of the spectrum and form factors of hadrons. Another key element is the explicit connection of AdS modes of total angular momentum $J$ with the internal structure of hadrons and the proper identification of the orbital angular momentum of the constituents. |
1808.00140 | Zhun Lu | Zhi-Lei Ma and Zhun Lu | Quark Wigner distribution of the pion meson in light-cone quark model | 9 pages, 3 figures | Phys. Rev. D 98, 054024 (2018) | 10.1103/PhysRevD.98.054024 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study the quark Wigner distributions of the pion meson which are the
phase-space distributions containing the most general one-parton
information.Using the pion wavefunctions deduced from a light-cone quark model,
we calculate the Wigner distributions of the unpolarized, longitudinally
polarized and transversely polarized quarks inside the pion meson via the
Fock-state overlap representation, respectively.We present the numerical
results of the transverse Wigner distributions in which the longitudinal
momentum fraction is integrated out. The mixed Wigner distributions as
functions of $b_y$ and $k_x$ are also presented.As a intermediate step, we
provide the analytic results for the generalized transverse momentum dependent
distributions of the pion meson in the same model.
| [
{
"created": "Wed, 1 Aug 2018 02:10:17 GMT",
"version": "v1"
}
] | 2018-10-03 | [
[
"Ma",
"Zhi-Lei",
""
],
[
"Lu",
"Zhun",
""
]
] | We study the quark Wigner distributions of the pion meson which are the phase-space distributions containing the most general one-parton information.Using the pion wavefunctions deduced from a light-cone quark model, we calculate the Wigner distributions of the unpolarized, longitudinally polarized and transversely polarized quarks inside the pion meson via the Fock-state overlap representation, respectively.We present the numerical results of the transverse Wigner distributions in which the longitudinal momentum fraction is integrated out. The mixed Wigner distributions as functions of $b_y$ and $k_x$ are also presented.As a intermediate step, we provide the analytic results for the generalized transverse momentum dependent distributions of the pion meson in the same model. |
1702.08666 | Yoshihiro Shigekami | P. Ko, Yuji Omura, Yoshihiro Shigekami and Chaehyun Yu | LHCb anomaly and $B$ physics in flavored Z$^{\prime}$ models with
flavored Higgs doublets | 28 pages, 5 figures, v2: texts and figures are improved | Phys. Rev. D 95, 115040 (2017) | 10.1103/PhysRevD.95.115040 | null | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study an extended Standard Model with a gauged U(1)$^{\prime}$ flavor
symmetry, motivated not only by the fermion mass hierarchy but also by the
excesses in $B \to K^{(*)} l l$ reported by the LHCb collaborations. The
U(1)$^{\prime}$ charges are assigned to quarks and leptons in a
flavor-dependent manner, and flavored Higgs doublets are also introduced in
order to detail the Yukawa couplings at the renormalizable level. Then, the
fermion mass hierarchy is realized by the vacuum alignment of the Higgs
doublets. In this model, flavor-changing currents involving the gauge boson of
U(1)$^{\prime}$ and the scalars generated by the Higgs doublets are predicted
and the observables in the $B \to K^{(*)} l l$ process possibly deviate from
the Standard Model predictions. We study the possibility that these new
flavor-changing interactions can explain the excesses in the $B \to K^{(*)} l
l$ process, and we derive some predictions for the other flavor-violating
processes based on the analysis. We specifically investigate the $\Delta F=2$
processes and the other $B$ decays: e.g., $B \to X_s \gamma$ and $B \to D^{(*)}
\tau \nu$, where the deviations are reported by the Belle and $BABAR$
collaborations.
| [
{
"created": "Tue, 28 Feb 2017 06:40:44 GMT",
"version": "v1"
},
{
"created": "Wed, 12 Jul 2017 09:58:46 GMT",
"version": "v2"
}
] | 2017-07-13 | [
[
"Ko",
"P.",
""
],
[
"Omura",
"Yuji",
""
],
[
"Shigekami",
"Yoshihiro",
""
],
[
"Yu",
"Chaehyun",
""
]
] | We study an extended Standard Model with a gauged U(1)$^{\prime}$ flavor symmetry, motivated not only by the fermion mass hierarchy but also by the excesses in $B \to K^{(*)} l l$ reported by the LHCb collaborations. The U(1)$^{\prime}$ charges are assigned to quarks and leptons in a flavor-dependent manner, and flavored Higgs doublets are also introduced in order to detail the Yukawa couplings at the renormalizable level. Then, the fermion mass hierarchy is realized by the vacuum alignment of the Higgs doublets. In this model, flavor-changing currents involving the gauge boson of U(1)$^{\prime}$ and the scalars generated by the Higgs doublets are predicted and the observables in the $B \to K^{(*)} l l$ process possibly deviate from the Standard Model predictions. We study the possibility that these new flavor-changing interactions can explain the excesses in the $B \to K^{(*)} l l$ process, and we derive some predictions for the other flavor-violating processes based on the analysis. We specifically investigate the $\Delta F=2$ processes and the other $B$ decays: e.g., $B \to X_s \gamma$ and $B \to D^{(*)} \tau \nu$, where the deviations are reported by the Belle and $BABAR$ collaborations. |
1209.3242 | Mikhail Vysotsky | M. I. Vysotsky | Screening of the Coulomb potential in superstrong magnetic field: atomic
levels and spontaneous production of positrons | The expanded variant of the lectures delivered at the 39th ITEP
Winter School in 2011. 22 pages, 7 figures, 6 tables | null | null | null | hep-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The expanded variant of the lectures delivered at the 39th ITEP Winter School
in 2011
| [
{
"created": "Fri, 14 Sep 2012 16:04:51 GMT",
"version": "v1"
},
{
"created": "Thu, 1 Nov 2012 11:19:38 GMT",
"version": "v2"
}
] | 2012-11-02 | [
[
"Vysotsky",
"M. I.",
""
]
] | The expanded variant of the lectures delivered at the 39th ITEP Winter School in 2011 |
1007.2645 | Michael Rauch | Sebastian Bock, Remi Lafaye, Tilman Plehn, Michael Rauch, Dirk Zerwas,
Peter M. Zerwas | Measuring Hidden Higgs and Strongly-Interacting Higgs Scenarios | 12 pages, 7 figures; version to be published in Phys. Lett. B | Phys.Lett.B694:44-53,2010 | 10.1016/j.physletb.2010.09.032 | KA-TP-20-2010, SFB/CPP-10-59 | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Higgs couplings can be affected by physics beyond the Standard Model. We
study modifications through interactions with a hidden sector and in specific
composite Higgs models accessible at the LHC. Both scenarios give rise to
congruent patterns of universal, or partially universal, shifts. In addition,
Higgs decays to the hidden sector may lead to invisible decay modes which we
also exploit. Experimental bounds on such potential modifications will measure
the concordance of an observed Higgs boson with the Standard Model.
| [
{
"created": "Thu, 15 Jul 2010 20:01:33 GMT",
"version": "v1"
},
{
"created": "Thu, 16 Sep 2010 20:08:17 GMT",
"version": "v2"
}
] | 2011-03-28 | [
[
"Bock",
"Sebastian",
""
],
[
"Lafaye",
"Remi",
""
],
[
"Plehn",
"Tilman",
""
],
[
"Rauch",
"Michael",
""
],
[
"Zerwas",
"Dirk",
""
],
[
"Zerwas",
"Peter M.",
""
]
] | Higgs couplings can be affected by physics beyond the Standard Model. We study modifications through interactions with a hidden sector and in specific composite Higgs models accessible at the LHC. Both scenarios give rise to congruent patterns of universal, or partially universal, shifts. In addition, Higgs decays to the hidden sector may lead to invisible decay modes which we also exploit. Experimental bounds on such potential modifications will measure the concordance of an observed Higgs boson with the Standard Model. |
hep-ph/0612167 | Ulrich Nierste | Alexander Lenz and Ulrich Nierste | Theoretical update of Bs-Bs-bar mixing | 38 pages, 7 figures, revised version to appear in JHEP, comments
added. We correct the incorrect use of an experimental input in eq. (93) and
Fig. 7. Our conclusions remain unchanged | JHEP 0706:072,2007 | 10.1088/1126-6708/2007/06/072 | TTP06-31 | hep-ph | null | We update the theory predictions for the mass difference $\dm_s$, the width
difference $\dg_s$ and the CP asymmetry in flavour-specific decays, $a_{\rm
fs}^{s}$, for the \bbs system. In particular we present a new expression for
the element $\Gamma_{12}^s$ of the decay matrix, which enters the predictions
of $\dg_s$ and $a_{\rm fs}^{s}$. To this end we introduce a new operator basis,
which reduces the troublesome sizes of the $1/m_b$ and $\alpha_s$ corrections
and diminishes the hadronic uncertainty in $\dg_s/\dm_s$ considerably.
Logarithms of the charm quark mass are summed to all orders. We find
$\dg_s/\dm_s= (49.7 \pm 9.4) \cdot 10^{-4}$ and $\dg_s =(f_{B_s}/240 {\rm
MeV})^2 [(0.105 \pm 0.016) B + (0.024 \pm 0.004) \tilde{B}_S' - 0.027 \pm
0.015] {ps}^{-1}$ in terms of the bag parameters $B$, $\tilde{B}_S'$ in the NDR
scheme and the decay constant $f_{B_s}$. The improved result for
$\Gamma_{12}^s$ also permits the extraction of the CP-violating \bbms phase
from $a_{\rm fs}^{s}$ with better accuracy. We show how the measurements of
$\Delta M_s$, $\Delta\Gamma_s$, $a_{\rm fs}^{s}$, $A_{\rm CP}^{\rm mix}(B_s\to
J/\psi \phi)$ and other observables can be efficiently combined to constrain
new physics. Applying our new formulae to data from the D{\O}experiment, we
find a 2$\sigma$ deviation of the \bbms phase from its Standard Model value. We
also briefly update the theory predictions for the \bbd system and find
$\dg_d/\dm_d = \lt(52.6 \epm{11.5}{12.8} \rt) \cdot 10^{-4}$ and $a_{\rm fs}^d
= \lt(-4.8\epm{1.0}{1.2} \rt) \cdot 10^{-4}$ in the Standard Model.
| [
{
"created": "Wed, 13 Dec 2006 20:33:10 GMT",
"version": "v1"
},
{
"created": "Tue, 12 Jun 2007 07:12:48 GMT",
"version": "v2"
},
{
"created": "Tue, 27 Nov 2007 15:59:36 GMT",
"version": "v3"
}
] | 2010-10-27 | [
[
"Lenz",
"Alexander",
""
],
[
"Nierste",
"Ulrich",
""
]
] | We update the theory predictions for the mass difference $\dm_s$, the width difference $\dg_s$ and the CP asymmetry in flavour-specific decays, $a_{\rm fs}^{s}$, for the \bbs system. In particular we present a new expression for the element $\Gamma_{12}^s$ of the decay matrix, which enters the predictions of $\dg_s$ and $a_{\rm fs}^{s}$. To this end we introduce a new operator basis, which reduces the troublesome sizes of the $1/m_b$ and $\alpha_s$ corrections and diminishes the hadronic uncertainty in $\dg_s/\dm_s$ considerably. Logarithms of the charm quark mass are summed to all orders. We find $\dg_s/\dm_s= (49.7 \pm 9.4) \cdot 10^{-4}$ and $\dg_s =(f_{B_s}/240 {\rm MeV})^2 [(0.105 \pm 0.016) B + (0.024 \pm 0.004) \tilde{B}_S' - 0.027 \pm 0.015] {ps}^{-1}$ in terms of the bag parameters $B$, $\tilde{B}_S'$ in the NDR scheme and the decay constant $f_{B_s}$. The improved result for $\Gamma_{12}^s$ also permits the extraction of the CP-violating \bbms phase from $a_{\rm fs}^{s}$ with better accuracy. We show how the measurements of $\Delta M_s$, $\Delta\Gamma_s$, $a_{\rm fs}^{s}$, $A_{\rm CP}^{\rm mix}(B_s\to J/\psi \phi)$ and other observables can be efficiently combined to constrain new physics. Applying our new formulae to data from the D{\O}experiment, we find a 2$\sigma$ deviation of the \bbms phase from its Standard Model value. We also briefly update the theory predictions for the \bbd system and find $\dg_d/\dm_d = \lt(52.6 \epm{11.5}{12.8} \rt) \cdot 10^{-4}$ and $a_{\rm fs}^d = \lt(-4.8\epm{1.0}{1.2} \rt) \cdot 10^{-4}$ in the Standard Model. |
2304.07080 | Kristjan Kannike | Kristjan Kannike | Dark matter induced dynamical symmetry breaking | 6 pages, 3 figures, contribution to the 2023 Electroweak session of
the 57th Rencontres de Moriond | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We consider the classically scale invariant Higgs-dilaton model of dynamical
symmetry breaking extended with an extra scalar field that plays the role of
dark matter. The Higgs boson is light near a critical boundary between
different symmetry breaking phases, where quantum corrections beyond the usual
Gildener-Weinberg approximation become relevant. The only large scale, which
generates the other scales, is given by the mass of dark matter. This implies a
tighter connection between dark matter and Higgs phenomenology. The model has
only three free parameters, yet it allows for the observed relic abundance of
dark matter while respecting all constraints. The direct detection cross
section mediated by the Higgs boson is determined by the dark matter mass alone
and is testable at future experiments.
| [
{
"created": "Fri, 14 Apr 2023 12:08:41 GMT",
"version": "v1"
}
] | 2023-04-17 | [
[
"Kannike",
"Kristjan",
""
]
] | We consider the classically scale invariant Higgs-dilaton model of dynamical symmetry breaking extended with an extra scalar field that plays the role of dark matter. The Higgs boson is light near a critical boundary between different symmetry breaking phases, where quantum corrections beyond the usual Gildener-Weinberg approximation become relevant. The only large scale, which generates the other scales, is given by the mass of dark matter. This implies a tighter connection between dark matter and Higgs phenomenology. The model has only three free parameters, yet it allows for the observed relic abundance of dark matter while respecting all constraints. The direct detection cross section mediated by the Higgs boson is determined by the dark matter mass alone and is testable at future experiments. |
hep-ph/0001240 | Anna Dubnickova | S. Dubnicka (SAS Bratislava), A.Z. Dubnickova, P. Weisenpacher
(Comenius University) | Non-Standard Model of the Nucleon Electromagnetic Structure and its
Predictability | Latex, 35 pages, 5 eps figures | null | null | null | hep-ph | null | Unitary and analytic ten-resonance model of the nucleon electromagnetic
(e.m.) structure with canonical normalizations and asymptotics is constructed
on a four-sheeted Riemann surface. It describes well all existing experimental
space-like and time-like data on the nucleon e.m. form factors (ff's),
including also FENICE (Frascati) results on the neutron, for the first time.
This is achieved without any external constraints on the isovector spectral
functions following from the piN-scattering data and pion e.m. ff behaviour
through the unitarity condition. Just opposite, the model itself predicts a
pronounced effect of the two-pion continuum on the isovector spectral functions
revealing the strong enhancement of the left wing of the rho(770)-resonance
close to two-pion threshold. The existence of the fourth excited state of the
rho(770) meson with parameters mass and width equal to 2506 MeV and 700 MeV,
respectively. The isoscalar spectral function behaviours are predicted by the
presented model.
| [
{
"created": "Mon, 24 Jan 2000 15:15:04 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Dubnicka",
"S.",
"",
"SAS Bratislava"
],
[
"Dubnickova",
"A. Z.",
"",
"Comenius University"
],
[
"Weisenpacher",
"P.",
"",
"Comenius University"
]
] | Unitary and analytic ten-resonance model of the nucleon electromagnetic (e.m.) structure with canonical normalizations and asymptotics is constructed on a four-sheeted Riemann surface. It describes well all existing experimental space-like and time-like data on the nucleon e.m. form factors (ff's), including also FENICE (Frascati) results on the neutron, for the first time. This is achieved without any external constraints on the isovector spectral functions following from the piN-scattering data and pion e.m. ff behaviour through the unitarity condition. Just opposite, the model itself predicts a pronounced effect of the two-pion continuum on the isovector spectral functions revealing the strong enhancement of the left wing of the rho(770)-resonance close to two-pion threshold. The existence of the fourth excited state of the rho(770) meson with parameters mass and width equal to 2506 MeV and 700 MeV, respectively. The isoscalar spectral function behaviours are predicted by the presented model. |
hep-ph/0110255 | Gino Isidori | Gino Isidori | Rare decays: theory vs. experiments | 20 pages, 9 figures, invited talk at 20th International Symposium on
Lepton and Photon Interactions at High Energies, Rome, August 2001; v2 & v3:
minor modifications, few references added | Int.J.Mod.Phys.A17:3078-3098,2002 | 10.1142/S0217751X02012612 | CERN-TH/2001-284 | hep-ph | null | We present an overview of rare K, D and B decays. Particular attention is
devoted to those flavour-changing neutral-current processes of K and B mesons
that offer the possibility of new significant tests of the Standard Model. The
sensitivity of these modes to physics beyond the Standard Model and the status
of their experimental study are also discussed.
| [
{
"created": "Thu, 18 Oct 2001 15:26:17 GMT",
"version": "v1"
},
{
"created": "Fri, 9 Nov 2001 17:28:40 GMT",
"version": "v2"
},
{
"created": "Tue, 20 Nov 2001 09:14:48 GMT",
"version": "v3"
}
] | 2010-11-23 | [
[
"Isidori",
"Gino",
""
]
] | We present an overview of rare K, D and B decays. Particular attention is devoted to those flavour-changing neutral-current processes of K and B mesons that offer the possibility of new significant tests of the Standard Model. The sensitivity of these modes to physics beyond the Standard Model and the status of their experimental study are also discussed. |
hep-ph/9602395 | Francesco Vissani | Francesco Vissani | $R$-Parity Breaking Phenomenology | LaTeX, 10 pages, 1 LaTeX figure; to appear in the proceedings of the
5th Hellenic School and Workshops on Elementary Particle Physics; minor
changes, 1 reference added | null | null | IC/96/32 | hep-ph | null | We review various features of the $R$-parity breaking phenomenology, with
particular attention to the low energy observables, and to the patterns of the
$R$-parity breaking interactions that arise in Grand Unified models.
| [
{
"created": "Mon, 26 Feb 1996 13:27:21 GMT",
"version": "v1"
},
{
"created": "Mon, 11 Mar 1996 18:41:40 GMT",
"version": "v2"
}
] | 2008-02-03 | [
[
"Vissani",
"Francesco",
""
]
] | We review various features of the $R$-parity breaking phenomenology, with particular attention to the low energy observables, and to the patterns of the $R$-parity breaking interactions that arise in Grand Unified models. |
1403.7503 | Vladyslav Pauk | Vladyslav Pauk, Marc Vanderhaeghen | Two-loop massive scalar three-point function in a dispersive approach | 13 pages, 11 figures | null | null | null | hep-ph nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present a dispersion relation formalism to calculate a massive scalar
two-loop vertex function. Such calculation is of direct relevance in the
evaluation of the hadronic light-by-light contribution to the muon's anomalous
magnetic moment due to meson poles. The discontinuity of the two-loop diagram
is obtained by a sum of two- and three-particle cut contributions, which
involve a phase space integration over the physical intermediate states. The
real part of the vertex function is subsequently reconstructed through
evaluation of a dispersion integral. We explicitly demonstrate that the
dispersive formalism yields exactly the same result as the direct two-loop
calculation.
| [
{
"created": "Fri, 28 Mar 2014 19:28:38 GMT",
"version": "v1"
},
{
"created": "Wed, 12 Nov 2014 14:59:17 GMT",
"version": "v2"
}
] | 2014-11-13 | [
[
"Pauk",
"Vladyslav",
""
],
[
"Vanderhaeghen",
"Marc",
""
]
] | We present a dispersion relation formalism to calculate a massive scalar two-loop vertex function. Such calculation is of direct relevance in the evaluation of the hadronic light-by-light contribution to the muon's anomalous magnetic moment due to meson poles. The discontinuity of the two-loop diagram is obtained by a sum of two- and three-particle cut contributions, which involve a phase space integration over the physical intermediate states. The real part of the vertex function is subsequently reconstructed through evaluation of a dispersion integral. We explicitly demonstrate that the dispersive formalism yields exactly the same result as the direct two-loop calculation. |
hep-ph/9807478 | Sasa Prelovsek | S. Prelovsek, S. Fajfer and P. Singer | Can FCNC transition $c\to ul^+l^-$ be seen in $D\to Vl^+l^-$ decays? | 3 pages, latex, 3 figures, Talk given by S. Prelovsek at the
Hyperons, Charm and Beauty Hadrons, Genova, Italy, 30 June -3 July 1998, to
appear as proceedings in Nucl. Phys. B | Nucl.Phys.Proc.Suppl.75B:141-143,1999 | 10.1016/S0920-5632(99)00224-8 | IJS-TP-98/17 | hep-ph | null | The decays $D\to Vl^+l^-$ present in principle the opportunity to observe the
short distance FCNC transition $c\to ul^+l^-$, which is sensitive to the
physics beyond the Standard Model. We analyze the $D \to V l^+ l^- $ decays
within the Standard Model, where in addition to the short distance dynamics
also the long distance dynamics is present. The short distance contribution due
to $c\to ul^+l^-$ transition, which is present only in the Cabibbo suppressed
decays, is found to be three orders of magnitude smaller than the long distance
contribution. The branching ratios well above $10^{-7}$ for Cabibbo suppressed
decays could signal new physics. The most frequent decays are the Cabibbo
allowed decays $D_s^+\to\rho^+\mu^+\mu^-$ and $D^0\to\bar K^{*0}\mu^+\mu^-$,
which are expected at the branching ratios of $3\cdot 10^{-5}$ and $1.7\cdot
10^{-6}$, respectively. These rates are not much lower than the present
experimental upper limit.
| [
{
"created": "Thu, 23 Jul 1998 14:06:02 GMT",
"version": "v1"
}
] | 2009-10-31 | [
[
"Prelovsek",
"S.",
""
],
[
"Fajfer",
"S.",
""
],
[
"Singer",
"P.",
""
]
] | The decays $D\to Vl^+l^-$ present in principle the opportunity to observe the short distance FCNC transition $c\to ul^+l^-$, which is sensitive to the physics beyond the Standard Model. We analyze the $D \to V l^+ l^- $ decays within the Standard Model, where in addition to the short distance dynamics also the long distance dynamics is present. The short distance contribution due to $c\to ul^+l^-$ transition, which is present only in the Cabibbo suppressed decays, is found to be three orders of magnitude smaller than the long distance contribution. The branching ratios well above $10^{-7}$ for Cabibbo suppressed decays could signal new physics. The most frequent decays are the Cabibbo allowed decays $D_s^+\to\rho^+\mu^+\mu^-$ and $D^0\to\bar K^{*0}\mu^+\mu^-$, which are expected at the branching ratios of $3\cdot 10^{-5}$ and $1.7\cdot 10^{-6}$, respectively. These rates are not much lower than the present experimental upper limit. |
hep-ph/0501018 | Sergey Troshin | S. M. Troshin, N. E. Tyurin | Cosmic rays and antishadowing | 6 pages, 3 figures, extended content | null | null | null | hep-ph astro-ph | null | We note that antishadowing could help in the explanation of cosmic rays
phenomena such as knee in the energetic spectrum and existence of penetrating
and long-flying particles.
| [
{
"created": "Tue, 4 Jan 2005 09:23:00 GMT",
"version": "v1"
},
{
"created": "Thu, 14 Apr 2005 07:22:46 GMT",
"version": "v2"
},
{
"created": "Fri, 27 May 2005 08:13:13 GMT",
"version": "v3"
}
] | 2007-05-23 | [
[
"Troshin",
"S. M.",
""
],
[
"Tyurin",
"N. E.",
""
]
] | We note that antishadowing could help in the explanation of cosmic rays phenomena such as knee in the energetic spectrum and existence of penetrating and long-flying particles. |
hep-ph/9906417 | Juergen Baacke | J. Baacke and C. Patzold | Out-of-equilibrium evolution of scalar fields in FRW cosmology:
renormalization and numerical simulations | 44 pages, uses latexsym, 6 pages with 11 figures in a .ps file | Phys.Rev. D61 (2000) 024016 | 10.1103/PhysRevD.61.024016 | DO-TH-99/09 | hep-ph | null | We present a renormalized computational framework for the evolution of a
self-interacting scalar field (inflaton) and its quantum fluctuations in an FRW
background geometry. We include a coupling of the field to the Ricci scalar
with a general coupling parameter $\xi$. We take into account the classical and
quantum back reactions, i.e., we consider the the dynamical evolution of the
cosmic scale factor. We perform, in the one-loop and in the large-N
approximation, the renormalization of the equation of motion for the inflaton
field, and of its energy momentum tensor. Our formalism is based on a
perturbative expansion for the mode functions, and uses dimensional
regularization. The renormalization procedure is manifestly covariant and the
counter terms are independent of the initial state. Some shortcomings in the
renormalization of the energy-momentum tensor in an earlier publication are
corrected. We avoid the occurence of initial singularities by constructing a
suitable class of initial states. The formalism is implemented numerically and
we present some results for the evolution in the post-inflationary preheating
era.
| [
{
"created": "Thu, 17 Jun 1999 15:52:03 GMT",
"version": "v1"
}
] | 2009-10-31 | [
[
"Baacke",
"J.",
""
],
[
"Patzold",
"C.",
""
]
] | We present a renormalized computational framework for the evolution of a self-interacting scalar field (inflaton) and its quantum fluctuations in an FRW background geometry. We include a coupling of the field to the Ricci scalar with a general coupling parameter $\xi$. We take into account the classical and quantum back reactions, i.e., we consider the the dynamical evolution of the cosmic scale factor. We perform, in the one-loop and in the large-N approximation, the renormalization of the equation of motion for the inflaton field, and of its energy momentum tensor. Our formalism is based on a perturbative expansion for the mode functions, and uses dimensional regularization. The renormalization procedure is manifestly covariant and the counter terms are independent of the initial state. Some shortcomings in the renormalization of the energy-momentum tensor in an earlier publication are corrected. We avoid the occurence of initial singularities by constructing a suitable class of initial states. The formalism is implemented numerically and we present some results for the evolution in the post-inflationary preheating era. |
0807.4474 | Markus Diehl | Daniela Amrath, Markus Diehl, Jean-Philippe Lansberg | Deeply virtual Compton scattering on a virtual pion target | 23 pages, 9 figures | Eur.Phys.J.C58:179-192,2008 | 10.1140/epjc/s10052-008-0769-1 | DESY 08-103, CPHT-RR007.0308 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study deeply virtual Compton scattering on a virtual pion that is emitted
by a proton. Using a range of models for the generalized parton distributions
of the pion, we evaluate the cross section, as well as the beam spin and beam
charge asymmetries in the leading-twist approximation. Studying Compton
scattering on the pion in suitable kinematics puts high demands on both beam
energy and luminosity, and we find that the corresponding requirements will
first be met after the energy upgrade at Jefferson Laboratory. As a by-product
of our study, we construct a parameterization of pion generalized parton
distributions that has a non-trivial interplay between the x and t dependence
and is in good agreement with form factor data and lattice calculations.
| [
{
"created": "Mon, 28 Jul 2008 15:33:54 GMT",
"version": "v1"
}
] | 2008-12-18 | [
[
"Amrath",
"Daniela",
""
],
[
"Diehl",
"Markus",
""
],
[
"Lansberg",
"Jean-Philippe",
""
]
] | We study deeply virtual Compton scattering on a virtual pion that is emitted by a proton. Using a range of models for the generalized parton distributions of the pion, we evaluate the cross section, as well as the beam spin and beam charge asymmetries in the leading-twist approximation. Studying Compton scattering on the pion in suitable kinematics puts high demands on both beam energy and luminosity, and we find that the corresponding requirements will first be met after the energy upgrade at Jefferson Laboratory. As a by-product of our study, we construct a parameterization of pion generalized parton distributions that has a non-trivial interplay between the x and t dependence and is in good agreement with form factor data and lattice calculations. |
hep-ph/9709236 | Hsiang-Nan Li | Hsiang-nan Li | A modified BFKL equation with unitarity | Conclusion is revised. One figure is added | Phys.Lett. B429 (1998) 121-126 | 10.1016/S0370-2693(98)00433-X | NCKU-HEP-97-05 | hep-ph | null | We propose a modified Balitskii-Fadin-Kuraev-Lipatov equation from the
viewpoint of the resummation technique, which satisfies the unitarity bound.
The idea is to relax the strong rapidity ordering and to restrict phase space
for real gluon emissions in the evaluation of the BFKL kernel. It is found that
the gluon distribution function rises as a power of the Bjorken variable $x$,
and then saturates at $x\to 0$. We estimate that the saturation begins to occur
for $x< 10^{-4}$.
| [
{
"created": "Thu, 4 Sep 1997 17:37:44 GMT",
"version": "v1"
},
{
"created": "Fri, 26 Sep 1997 06:30:21 GMT",
"version": "v2"
}
] | 2009-10-30 | [
[
"Li",
"Hsiang-nan",
""
]
] | We propose a modified Balitskii-Fadin-Kuraev-Lipatov equation from the viewpoint of the resummation technique, which satisfies the unitarity bound. The idea is to relax the strong rapidity ordering and to restrict phase space for real gluon emissions in the evaluation of the BFKL kernel. It is found that the gluon distribution function rises as a power of the Bjorken variable $x$, and then saturates at $x\to 0$. We estimate that the saturation begins to occur for $x< 10^{-4}$. |
2205.13118 | Yu-Qi Xiao | Shao-Long Chen and Yu-Qi Xiao | The Neutrinoless Double Beta Decay in the Colored Zee-Babu Model | 18 pages, 3 figures, references added | null | 10.1016/j.nuclphysb.2022.116041 | null | hep-ph | http://creativecommons.org/licenses/by/4.0/ | We study the neutrinoless double beta decay in the colored Zee-Babu model. We
consider three cases of the colored Zee-Babu model with a leptoquark and a
diquark introduced. The neutrino masses are generated at two-loop level, and
the constraints given by tree-level flavor violation processes and muon
anomalous magnetic moment $(g-2)_{\mu}$ have been considered. In our numerical
analysis, we find that the standard light neutrino exchange contribution can be
canceled by new physics contribution under certain assumption and condition,
leading to a hidden neutrinoless double beta decay. The condition can be
examined comprehensively by future complementary searches with different
isotopes.
| [
{
"created": "Thu, 26 May 2022 02:56:02 GMT",
"version": "v1"
},
{
"created": "Mon, 6 Jun 2022 07:53:43 GMT",
"version": "v2"
}
] | 2022-12-28 | [
[
"Chen",
"Shao-Long",
""
],
[
"Xiao",
"Yu-Qi",
""
]
] | We study the neutrinoless double beta decay in the colored Zee-Babu model. We consider three cases of the colored Zee-Babu model with a leptoquark and a diquark introduced. The neutrino masses are generated at two-loop level, and the constraints given by tree-level flavor violation processes and muon anomalous magnetic moment $(g-2)_{\mu}$ have been considered. In our numerical analysis, we find that the standard light neutrino exchange contribution can be canceled by new physics contribution under certain assumption and condition, leading to a hidden neutrinoless double beta decay. The condition can be examined comprehensively by future complementary searches with different isotopes. |
1411.2606 | Ariel Zhitnitsky | Ariel R. Zhitnitsky | The topological long range order in QCD. Applications to heavy ion
collisions and cosmology | Prepare for the proceedings of the 3rd International Conference on
New Frontiers in Physics (ICNFP-2014), Kolymbari, Crete, 2014, 14 pages, 4
figures | null | null | null | hep-ph gr-qc hep-lat hep-th nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We argue that the local violation of P invariance in heavy ion collisions is
a consequence of the long range topological order which is inherent feature of
strongly coupled QCD. A similar phenomenon is known to occur in some
topologically ordered condensed matter systems with a gap. We also discuss
possible cosmological applications of this long range order in strongly coupled
gauge theories. In particular, we argue that the de Sitter behaviour might be
dynamically generated as a result of the long range order. In this framework
the inflaton is an auxiliary field which effectively describes the dynamics of
topological sectors in a gauge theory in the expanding universe, rather than a
new dynamical degree of freedom.
| [
{
"created": "Mon, 10 Nov 2014 21:02:19 GMT",
"version": "v1"
}
] | 2014-11-12 | [
[
"Zhitnitsky",
"Ariel R.",
""
]
] | We argue that the local violation of P invariance in heavy ion collisions is a consequence of the long range topological order which is inherent feature of strongly coupled QCD. A similar phenomenon is known to occur in some topologically ordered condensed matter systems with a gap. We also discuss possible cosmological applications of this long range order in strongly coupled gauge theories. In particular, we argue that the de Sitter behaviour might be dynamically generated as a result of the long range order. In this framework the inflaton is an auxiliary field which effectively describes the dynamics of topological sectors in a gauge theory in the expanding universe, rather than a new dynamical degree of freedom. |
hep-ph/9705289 | Masayuki Uehara | S. Saito(Nagoya University) and M. Uehara(Saga University) | Do really the seagull terms survive for the electric polarizability of
the nucleon | 9 pages | Nucl.Phys. A628 (1998) 112-118 | 10.1016/S0375-9474(97)00621-0 | SAGA-HE-123 | hep-ph | null | The seagull terms for the electric polarizability of the nucleon are shown to
vanish, if one introduces fluctuations around the Skyrmion, and the origin of
the eletric polarizability cannot be attributed to the seagull terms in the
Skyrme model.
| [
{
"created": "Mon, 12 May 1997 06:08:15 GMT",
"version": "v1"
}
] | 2009-10-30 | [
[
"Saito",
"S.",
"",
"Nagoya University"
],
[
"Uehara",
"M.",
"",
"Saga University"
]
] | The seagull terms for the electric polarizability of the nucleon are shown to vanish, if one introduces fluctuations around the Skyrmion, and the origin of the eletric polarizability cannot be attributed to the seagull terms in the Skyrme model. |
1007.1151 | Ulrich Ellwanger | Debottam Das and Ulrich Ellwanger | Light dark matter in the NMSSM: upper bounds on direct detection cross
sections | 17 pages, 3 figures | JHEP 1009:085,2010 | 10.1007/JHEP09(2010)085 | LPT Orsay 10-53 | hep-ph astro-ph.HE | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In the Next-to-Minimal Supersymmetric Standard Model, a bino-like LSP can be
as light as a few GeV and satisfy WMAP constraints on the dark matter relic
density in the presence of a light CP-odd Higgs scalar. We study upper bounds
on the direct detection cross sections for such a light LSP in the mass range
2-20 GeV in the NMSSM, respecting all constraints from B-physics and LEP. The
OPAL constraints on e^+ e^- -> \chi^0_1 \chi^0_i (i > 1) play an important role
and are discussed in some detail. The resulting upper bounds on the
spin-independent and spin-dependent nucleon cross sections are ~ 10^{-42}
cm^{-2} and ~ 4\times 10^{-40} cm^{-2}, respectively. Hence the upper bound on
the spin-independent cross section is below the DAMA and CoGeNT regions, but
could be compatible with the two events observed by CDMS-II.
| [
{
"created": "Wed, 7 Jul 2010 14:45:13 GMT",
"version": "v1"
}
] | 2014-11-21 | [
[
"Das",
"Debottam",
""
],
[
"Ellwanger",
"Ulrich",
""
]
] | In the Next-to-Minimal Supersymmetric Standard Model, a bino-like LSP can be as light as a few GeV and satisfy WMAP constraints on the dark matter relic density in the presence of a light CP-odd Higgs scalar. We study upper bounds on the direct detection cross sections for such a light LSP in the mass range 2-20 GeV in the NMSSM, respecting all constraints from B-physics and LEP. The OPAL constraints on e^+ e^- -> \chi^0_1 \chi^0_i (i > 1) play an important role and are discussed in some detail. The resulting upper bounds on the spin-independent and spin-dependent nucleon cross sections are ~ 10^{-42} cm^{-2} and ~ 4\times 10^{-40} cm^{-2}, respectively. Hence the upper bound on the spin-independent cross section is below the DAMA and CoGeNT regions, but could be compatible with the two events observed by CDMS-II. |
hep-ph/9710406 | null | Gouranga C Nayak and V. Ravishankar (Dept. of Physics, Indian
Institute of Technology, Kanpur. INDIA) | Pre-equilibrium evolution of quark-gluon plasma | 22 pages Latex, 14 postscript figures; Minor changes are made: To
appear in Physical Reveiw C | Phys.Rev.C58:356-364,1998 | 10.1103/PhysRevC.58.356 | null | hep-ph nucl-th | null | We study the production and the evolution of quark-gluon plasma expected to
be formed in ultra relativistic heavy-ion collisions, within the color
flux-tube model. We introduce the gluonic component in the Boltzmann equation,
which we solve in the phase space which is extended to include the SU(3) color
degree of freedom. The color degree of freedom is shown to play a decisive role
in equilibration, and in fixing the temperature of the plasma. We further find
that the soft partons that we study here contribute substantially to the bulk
properties. Finally, the model is shown to provide a detailed picture of how
the quark-gluon plasma evolves and is driven towards a hydrodynamic flow, which
starts occuring around 1 $fm$.
| [
{
"created": "Mon, 20 Oct 1997 11:07:31 GMT",
"version": "v1"
},
{
"created": "Wed, 15 Apr 1998 05:02:40 GMT",
"version": "v2"
}
] | 2008-11-26 | [
[
"Nayak",
"Gouranga C",
"",
"Dept. of Physics, Indian\n Institute of Technology, Kanpur. INDIA"
],
[
"Ravishankar",
"V.",
"",
"Dept. of Physics, Indian\n Institute of Technology, Kanpur. INDIA"
]
] | We study the production and the evolution of quark-gluon plasma expected to be formed in ultra relativistic heavy-ion collisions, within the color flux-tube model. We introduce the gluonic component in the Boltzmann equation, which we solve in the phase space which is extended to include the SU(3) color degree of freedom. The color degree of freedom is shown to play a decisive role in equilibration, and in fixing the temperature of the plasma. We further find that the soft partons that we study here contribute substantially to the bulk properties. Finally, the model is shown to provide a detailed picture of how the quark-gluon plasma evolves and is driven towards a hydrodynamic flow, which starts occuring around 1 $fm$. |
1010.4623 | Ming Zhen Zhou | Jian-Mei Hou, Chang-Qiao Du, Hong Chen, Ming-Zhen Zhou | Radiative vertex $VP\gamma$ and $\eta-\eta'$ mixing in light-cone sum
rules | 9 pages, 12 figures, 2 tables | Phys.Lett.B696:51-57,2011 | 10.1016/j.physletb.2010.12.002 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this work, we calculate radiative vertex $VP\gamma$ ($V=\phi,\omega,\rho$
and $P=\eta,\eta'$) by utilizing $\omega-\phi$ mixing scheme and taking into
account the contributions of the three-particle twist-4 distribution amplitudes
of the photon in QCD sum rules on light cone. According to experimental data of
$V\rightarrow P\gamma$ and $P\rightarrow V\gamma$ from PDG, a value of the
$\eta-\eta^\prime$ mixing angle, $\phi=(40.9\pm0.5)^\circ$, is extracted in the
framework of the quark-flavor basis to describe the $\eta-\eta^\prime$ system.
| [
{
"created": "Fri, 22 Oct 2010 06:53:32 GMT",
"version": "v1"
},
{
"created": "Thu, 6 Jan 2011 02:13:31 GMT",
"version": "v2"
}
] | 2011-01-27 | [
[
"Hou",
"Jian-Mei",
""
],
[
"Du",
"Chang-Qiao",
""
],
[
"Chen",
"Hong",
""
],
[
"Zhou",
"Ming-Zhen",
""
]
] | In this work, we calculate radiative vertex $VP\gamma$ ($V=\phi,\omega,\rho$ and $P=\eta,\eta'$) by utilizing $\omega-\phi$ mixing scheme and taking into account the contributions of the three-particle twist-4 distribution amplitudes of the photon in QCD sum rules on light cone. According to experimental data of $V\rightarrow P\gamma$ and $P\rightarrow V\gamma$ from PDG, a value of the $\eta-\eta^\prime$ mixing angle, $\phi=(40.9\pm0.5)^\circ$, is extracted in the framework of the quark-flavor basis to describe the $\eta-\eta^\prime$ system. |
0903.0005 | Rikkert Frederix | John M. Campbell, Rikkert Frederix, Fabio Maltoni, Francesco
Tramontano | Next-to-leading-order predictions for t-channel single-top production at
hadron colliders | 5 pages, 5 figures. Updated results with more recent CTEQ6.6 PDF set.
Included PDF uncertainties | Phys.Rev.Lett.102:182003,2009 | 10.1103/PhysRevLett.102.182003 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present the predictions at next-to-leading order (NLO) in the strong
coupling for the single-top cross section in the t channel at the Tevatron and
the LHC. Our calculation starts from the 2 -> 3 Born amplitude g q -> t bbar
q', keeping the b-quark mass non-zero. A comparison is performed with a
traditional NLO calculation of this channel based on the 2 -> 2 Born process
with a bottom quark in the initial state. In particular, the effect of using
kinematic approximations and resumming logarithms of the form log(Q^2/m_b^2) in
the 2 -> 2 process is assessed. Our results show that the 2 -> 3 calculation is
very well behaved and in substantial agreement with the predictions based on
the 2 -> 2 process.
| [
{
"created": "Mon, 2 Mar 2009 11:18:31 GMT",
"version": "v1"
},
{
"created": "Fri, 1 May 2009 13:44:09 GMT",
"version": "v2"
}
] | 2009-06-30 | [
[
"Campbell",
"John M.",
""
],
[
"Frederix",
"Rikkert",
""
],
[
"Maltoni",
"Fabio",
""
],
[
"Tramontano",
"Francesco",
""
]
] | We present the predictions at next-to-leading order (NLO) in the strong coupling for the single-top cross section in the t channel at the Tevatron and the LHC. Our calculation starts from the 2 -> 3 Born amplitude g q -> t bbar q', keeping the b-quark mass non-zero. A comparison is performed with a traditional NLO calculation of this channel based on the 2 -> 2 Born process with a bottom quark in the initial state. In particular, the effect of using kinematic approximations and resumming logarithms of the form log(Q^2/m_b^2) in the 2 -> 2 process is assessed. Our results show that the 2 -> 3 calculation is very well behaved and in substantial agreement with the predictions based on the 2 -> 2 process. |
1903.05101 | Yonit Hochberg | Yonit Hochberg, Ilya Charaev, Sae-Woo Nam, Varun Verma, Marco
Colangelo, Karl K. Berggren | Detecting Dark Matter with Superconducting Nanowires | 7 pages, 4 figures | Phys. Rev. Lett. 123, 151802 (2019) | 10.1103/PhysRevLett.123.151802 | null | hep-ph cond-mat.supr-con hep-ex quant-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We propose the use of superconducting nanowires as both target and sensor for
direct detection of sub-GeV dark matter. With excellent sensitivity to small
energy deposits on electrons, and demonstrated low dark counts, such devices
could be used to probe electron recoils from dark matter scattering and
absorption processes. We demonstrate the feasibility of this idea using
measurements of an existing fabricated tungsten-silicide nanowire prototype
with 0.8 eV energy threshold and 4.3 nanograms with 10 thousand seconds of
exposure, which showed no dark counts. The results from this device already
place meaningful bounds on dark matter-electron interactions, including the
strongest terrestrial bounds on sub-eV dark photon absorption to date. Future
expected fabrication on larger scales and with lower thresholds should enable
probing new territory in the direct detection landscape, establishing the
complementarity of this approach to other existing proposals.
| [
{
"created": "Tue, 12 Mar 2019 18:00:06 GMT",
"version": "v1"
}
] | 2019-10-16 | [
[
"Hochberg",
"Yonit",
""
],
[
"Charaev",
"Ilya",
""
],
[
"Nam",
"Sae-Woo",
""
],
[
"Verma",
"Varun",
""
],
[
"Colangelo",
"Marco",
""
],
[
"Berggren",
"Karl K.",
""
]
] | We propose the use of superconducting nanowires as both target and sensor for direct detection of sub-GeV dark matter. With excellent sensitivity to small energy deposits on electrons, and demonstrated low dark counts, such devices could be used to probe electron recoils from dark matter scattering and absorption processes. We demonstrate the feasibility of this idea using measurements of an existing fabricated tungsten-silicide nanowire prototype with 0.8 eV energy threshold and 4.3 nanograms with 10 thousand seconds of exposure, which showed no dark counts. The results from this device already place meaningful bounds on dark matter-electron interactions, including the strongest terrestrial bounds on sub-eV dark photon absorption to date. Future expected fabrication on larger scales and with lower thresholds should enable probing new territory in the direct detection landscape, establishing the complementarity of this approach to other existing proposals. |
hep-ph/0004023 | Yoav Achiman | Yoav Achiman and Carsten Merten | Large Quark Rotations, Neutrino mixing and Proton Decay | Latex2e file with 3 PS figures, minor corrections,the final version
to be published in Nucl. Phys. B | Nucl.Phys. B584 (2000) 46-68 | 10.1016/S0550-3213(00)00353-9 | WUB 00-03, TAUP 2627-2000 | hep-ph | null | Right-handed (RH) rotations do not play a role in the Standard Model, and
only the differences of the LH mixing angles are involved in ${\bf V}_{\scr
\textrm{CKM}}$. This leads to the huge freedom in the fermionic mass matrices.
However, that is no more true in extensions of the Standard Model. For example
in GUTs large RH rotations of the quarks can be related to the observed large
neutrino mixing or in particular, all mixing angles are relevant for the proton
decay. We present a simple realistic non-SUSY SO(10) GUT with large RH and LH
mixing and study the corresponding nucleon decay rates.
| [
{
"created": "Tue, 4 Apr 2000 13:17:09 GMT",
"version": "v1"
},
{
"created": "Tue, 30 May 2000 11:40:22 GMT",
"version": "v2"
}
] | 2009-10-31 | [
[
"Achiman",
"Yoav",
""
],
[
"Merten",
"Carsten",
""
]
] | Right-handed (RH) rotations do not play a role in the Standard Model, and only the differences of the LH mixing angles are involved in ${\bf V}_{\scr \textrm{CKM}}$. This leads to the huge freedom in the fermionic mass matrices. However, that is no more true in extensions of the Standard Model. For example in GUTs large RH rotations of the quarks can be related to the observed large neutrino mixing or in particular, all mixing angles are relevant for the proton decay. We present a simple realistic non-SUSY SO(10) GUT with large RH and LH mixing and study the corresponding nucleon decay rates. |
hep-ph/0305212 | Keith Olive | J. Ellis (CERN), K.A. Olive (FTPI, U of Minnesota), Y. Santoso (FTPI,
U of Minnesota), V.C. Spanos (FTPI, U of Minnesota) | Phenomenological Constraints on Patterns of Supersymmetry Breaking | 17 pages LaTeX, 9 eps figures | Phys.Lett.B573:162-172,2003 | 10.1016/j.physletb.2003.08.056 | CERN-TH/2003-107,UMN-TH-2201/03,FTPI-MINN-03/12 | hep-ph astro-ph | null | Specific models of supersymmetry breaking predict relations between the
trilinear and bilinear soft supersymmetry breaking parameters A_0 and B_0 at
the input scale. In such models, the value of tan beta can be calculated as a
function of the scalar masses m_0 and the gaugino masses m_{1/2}, which we
assume to be universal. The experimental constraints on sparticle and Higgs
masses, b to s gamma decay and the cold dark matter density Omega_{CDM} h^2 can
then be used to constrain tan beta in such specific models of supersymmetry
breaking. In the simplest Polonyi model with A_0 = (3 - sqrt{3})m_0 = B_0 +
m_0, we find 11 < tan beta < 20 (tan beta ~ 4.15) for mu > 0 (mu < 0). We also
discuss other models with A_0 = B_0 + m_0, finding that only the range -1.9 <
A_0/m_0 < 2.5 is allowed for mu > 0, and the range 1.25 < A_0/m_0 < 4.8 for mu
< 0. In these models, we find no solutions in the rapid-annihilation `funnels'
or in the `focus-point' region. We also discuss the allowed range of tan beta
in the no-scale model with A_0 = B_0 = 0. In all these models, most of the
allowed regions are in the chi - stau_1 coannihilation `tail'.
| [
{
"created": "Tue, 20 May 2003 16:48:50 GMT",
"version": "v1"
}
] | 2008-11-26 | [
[
"Ellis",
"J.",
"",
"CERN"
],
[
"Olive",
"K. A.",
"",
"FTPI, U of Minnesota"
],
[
"Santoso",
"Y.",
"",
"FTPI,\n U of Minnesota"
],
[
"Spanos",
"V. C.",
"",
"FTPI, U of Minnesota"
]
] | Specific models of supersymmetry breaking predict relations between the trilinear and bilinear soft supersymmetry breaking parameters A_0 and B_0 at the input scale. In such models, the value of tan beta can be calculated as a function of the scalar masses m_0 and the gaugino masses m_{1/2}, which we assume to be universal. The experimental constraints on sparticle and Higgs masses, b to s gamma decay and the cold dark matter density Omega_{CDM} h^2 can then be used to constrain tan beta in such specific models of supersymmetry breaking. In the simplest Polonyi model with A_0 = (3 - sqrt{3})m_0 = B_0 + m_0, we find 11 < tan beta < 20 (tan beta ~ 4.15) for mu > 0 (mu < 0). We also discuss other models with A_0 = B_0 + m_0, finding that only the range -1.9 < A_0/m_0 < 2.5 is allowed for mu > 0, and the range 1.25 < A_0/m_0 < 4.8 for mu < 0. In these models, we find no solutions in the rapid-annihilation `funnels' or in the `focus-point' region. We also discuss the allowed range of tan beta in the no-scale model with A_0 = B_0 = 0. In all these models, most of the allowed regions are in the chi - stau_1 coannihilation `tail'. |
2101.08265 | Anders Eller Thomsen Ph.D. | Anders Eller Thomsen | RGBeta: A Mathematica Package for the Evaluation of Renormalization
Group $ \beta $-Functions | 27 pages, 3 tables. The package, tutorial notebook, and sample files
are available at https://github.com/aethomsen/RGBeta | null | null | null | hep-ph | http://creativecommons.org/licenses/by/4.0/ | In completely generic four-dimensional gauge-Yukawa theories, the
renormalization group $ \beta $-functions are known to the 3-2-2 loop order in
gauge, Yukawa, and quartic couplings, respectively. It does, however, remain
difficult to apply these results to specific models without the use of
dedicated computer tools. We describe a procedure for extracting $ \beta
$-functions using the general results and introduce RGBeta, a dedicated
Mathematica package for extracting the $ \overline{\text{MS}} $ $ \beta
$-functions in broad classes of models. The package and example notebooks are
available from the GitHub repository at https://github.com/aethomsen/RGBeta .
| [
{
"created": "Wed, 20 Jan 2021 19:00:00 GMT",
"version": "v1"
}
] | 2021-01-22 | [
[
"Thomsen",
"Anders Eller",
""
]
] | In completely generic four-dimensional gauge-Yukawa theories, the renormalization group $ \beta $-functions are known to the 3-2-2 loop order in gauge, Yukawa, and quartic couplings, respectively. It does, however, remain difficult to apply these results to specific models without the use of dedicated computer tools. We describe a procedure for extracting $ \beta $-functions using the general results and introduce RGBeta, a dedicated Mathematica package for extracting the $ \overline{\text{MS}} $ $ \beta $-functions in broad classes of models. The package and example notebooks are available from the GitHub repository at https://github.com/aethomsen/RGBeta . |
hep-ph/9905206 | Palash Baran Pal | Avijit K. Ganguly, Sushan Konar, Palash B. Pal | Faraday effect : a field theoretical point of view | 20 pages, Latex, uses axodraw.sty | Phys. Rev. D 60, 105014 (1999) | 10.1103/PhysRevD.60.105014 | SINP/TNP/99-15 | hep-ph | null | We analyze the structure of the vacuum polarization tensor in the presence of
a background electromagnetic field in a medium. We use various discrete
symmetries and crossing symmetry to constrain the form factors obtained for the
most general case. From these symmetry arguments, we show why the vacuum
polarization tensor has to be even in the background field when there is no
background medium. Taking then the background field to be purely magnetic, we
evaluate the vacuum polarization to linear order in it. The result shows the
phenomenon of Faraday rotation, i.e., the rotation of the plane of polarization
of a plane polarized light passing through this background. We find that the
usual expression for Faraday rotation, which is derived for a non-degenerate
plasma in the non-relativistic approximation, undergoes substantial
modification if the background is degenerate and/or relativistic. We give
explicit expressions for Faraday rotation in completely degenerate and
ultra-relativistic media.
| [
{
"created": "Mon, 3 May 1999 11:18:04 GMT",
"version": "v1"
},
{
"created": "Mon, 28 Jun 1999 04:51:09 GMT",
"version": "v2"
}
] | 2016-08-25 | [
[
"Ganguly",
"Avijit K.",
""
],
[
"Konar",
"Sushan",
""
],
[
"Pal",
"Palash B.",
""
]
] | We analyze the structure of the vacuum polarization tensor in the presence of a background electromagnetic field in a medium. We use various discrete symmetries and crossing symmetry to constrain the form factors obtained for the most general case. From these symmetry arguments, we show why the vacuum polarization tensor has to be even in the background field when there is no background medium. Taking then the background field to be purely magnetic, we evaluate the vacuum polarization to linear order in it. The result shows the phenomenon of Faraday rotation, i.e., the rotation of the plane of polarization of a plane polarized light passing through this background. We find that the usual expression for Faraday rotation, which is derived for a non-degenerate plasma in the non-relativistic approximation, undergoes substantial modification if the background is degenerate and/or relativistic. We give explicit expressions for Faraday rotation in completely degenerate and ultra-relativistic media. |
1409.6383 | Yasuhiko Tsue | Y. Tsue (Kochi Univ., Japan), J. da Providencia (Univ. de Coimbra,
Portugal), C. Providencia (Univ. de Coimbra, Portugal), M. Yamamura (Kansai
Univ., Japan), H. Bohr (Danish Technical Univ., Denmark) | Spin Polarization versus Color-Flavor-Locking in High Density Quark
Matter | 23 pages, 4 figures | null | 10.1093/ptep/ptu172 | null | hep-ph nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | It is shown that spin polarization with respect to each flavor in
three-flavor quark matter occurs instead of the color-flavor locking at high
baryon density by using the Nambu-Jona-Lasinio model with four-point
tensor-type interaction. Also, it is indicated that the order of phase
transition between the color-flavor locked phase and the spin polarized phase
is the first order by means of the second order perturbation theory.
| [
{
"created": "Tue, 23 Sep 2014 01:26:36 GMT",
"version": "v1"
},
{
"created": "Thu, 27 Nov 2014 02:03:04 GMT",
"version": "v2"
}
] | 2015-01-21 | [
[
"Tsue",
"Y.",
"",
"Kochi Univ., Japan"
],
[
"da Providencia",
"J.",
"",
"Univ. de Coimbra,\n Portugal"
],
[
"Providencia",
"C.",
"",
"Univ. de Coimbra, Portugal"
],
[
"Yamamura",
"M.",
"",
"Kansai\n Univ., Japan"
],
[
"Bohr",
... | It is shown that spin polarization with respect to each flavor in three-flavor quark matter occurs instead of the color-flavor locking at high baryon density by using the Nambu-Jona-Lasinio model with four-point tensor-type interaction. Also, it is indicated that the order of phase transition between the color-flavor locked phase and the spin polarized phase is the first order by means of the second order perturbation theory. |
1509.05615 | Lucien Heurtier | Otilia Ducu, Lucien Heurtier, and Julien Maurer | LHC signatures of a Z' mediator between dark matter and the SU(3) sector | 17 pages, 6 figures | null | 10.1007/JHEP03(2016)006 | null | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this paper, we study the experimental signatures of a gluophilic $Z'$ at
the LHC, in particular through the analysis of three jets or four tops events.
The $Z'$ couples to gluons through dimension six operators and the parameter
space is constrained with experimental searches released at 7 and 8
$\mathrm{TeV}$ by CMS along these two different channels. Existing constraints
coming from the study of dark matter where the $Z'$ represents a possible
mediator between the latter and the Standard Model are also included for
comparison. Prospects at $\sqrt s=13$ TeV allow us to evaluate for which values
of the parameter space a gluophilic $Z'$ could be discovered during the next
run of the LHC. In particular, we show that the analysis of the three jets
invariant mass could provide a clear signal ($>5\sigma$) for masses of the $Z'$
above 300 $\mathrm{GeV}$. Four tops events bring in addition further discovery
potential for heavy $Z'$ (above $\sim 2~\mathrm{TeV}$). A combination of both
signals in four top channels and three jets analyses during the next run of the
LHC could thus provide a clear signal of the presence of a heavy gluophilic
$Z'$.
| [
{
"created": "Fri, 18 Sep 2015 13:16:34 GMT",
"version": "v1"
}
] | 2016-03-23 | [
[
"Ducu",
"Otilia",
""
],
[
"Heurtier",
"Lucien",
""
],
[
"Maurer",
"Julien",
""
]
] | In this paper, we study the experimental signatures of a gluophilic $Z'$ at the LHC, in particular through the analysis of three jets or four tops events. The $Z'$ couples to gluons through dimension six operators and the parameter space is constrained with experimental searches released at 7 and 8 $\mathrm{TeV}$ by CMS along these two different channels. Existing constraints coming from the study of dark matter where the $Z'$ represents a possible mediator between the latter and the Standard Model are also included for comparison. Prospects at $\sqrt s=13$ TeV allow us to evaluate for which values of the parameter space a gluophilic $Z'$ could be discovered during the next run of the LHC. In particular, we show that the analysis of the three jets invariant mass could provide a clear signal ($>5\sigma$) for masses of the $Z'$ above 300 $\mathrm{GeV}$. Four tops events bring in addition further discovery potential for heavy $Z'$ (above $\sim 2~\mathrm{TeV}$). A combination of both signals in four top channels and three jets analyses during the next run of the LHC could thus provide a clear signal of the presence of a heavy gluophilic $Z'$. |
1303.3271 | Matthew Reece | JiJi Fan, Andrey Katz, Lisa Randall, Matthew Reece | A Dark-Disk Universe | Concise companion to arXiv:1303.1521; v2: published in PRL,
references added | null | 10.1103/PhysRevLett.110.211302 | null | hep-ph astro-ph.CO | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We point out that current constraints on dark matter imply only that the
majority of dark matter is cold and collisionless. A subdominant fraction of
dark matter could have much stronger interactions. In particular, it could
interact in a manner that dissipates energy, thereby cooling into a
rotationally-supported disk, much as baryons do. We call this proposed new dark
matter component Double-Disk Dark Matter (DDDM). We argue that DDDM could
constitute a fraction of all matter roughly as large as the fraction in
baryons, and that it could be detected through its gravitational effects on the
motion of stars in galaxies, for example. Furthermore, if DDDM can annihilate
to gamma rays, it would give rise to an indirect detection signal distributed
across the sky that differs dramatically from that predicted for ordinary dark
matter. DDDM and more general partially interacting dark matter scenarios
provide a large unexplored space of testable new physics ideas.
| [
{
"created": "Wed, 13 Mar 2013 20:00:02 GMT",
"version": "v1"
},
{
"created": "Sat, 3 Aug 2013 17:53:40 GMT",
"version": "v2"
}
] | 2013-08-06 | [
[
"Fan",
"JiJi",
""
],
[
"Katz",
"Andrey",
""
],
[
"Randall",
"Lisa",
""
],
[
"Reece",
"Matthew",
""
]
] | We point out that current constraints on dark matter imply only that the majority of dark matter is cold and collisionless. A subdominant fraction of dark matter could have much stronger interactions. In particular, it could interact in a manner that dissipates energy, thereby cooling into a rotationally-supported disk, much as baryons do. We call this proposed new dark matter component Double-Disk Dark Matter (DDDM). We argue that DDDM could constitute a fraction of all matter roughly as large as the fraction in baryons, and that it could be detected through its gravitational effects on the motion of stars in galaxies, for example. Furthermore, if DDDM can annihilate to gamma rays, it would give rise to an indirect detection signal distributed across the sky that differs dramatically from that predicted for ordinary dark matter. DDDM and more general partially interacting dark matter scenarios provide a large unexplored space of testable new physics ideas. |
hep-ph/9604409 | W. S. Hou | George Wei-Shu Hou (National Taiwan University) | Like Sign Top Pair Production via $e^+e^-\to h^0A^0 \to tt\bar c\bar c$ | 10 pages, latex, no figures. Talk presented at LCWS95, September
1995, Morioka-Appi, Japan | null | null | NTUTH-96-02 | hep-ph | null | We discuss the possibility and likelihood that one may observe {\it like
sign} top quark pair production at the Linear Collider. In general two Higgs
models, flavor changing couplings involving top quark could be quite sizable.
Exotic neutral Higgs bosons may decay dominantly via $t\bar c$ or $\bar tc$
channels. At the linear collider, $e^+e^- \to h^0A^0$ or $H^0A^0$ production
processes could lead to $b\bar bt\bar c$, $W^+W^-t\bar c$ or $tt\bar c\bar c$
(or $\bar t\bar tcc$) final states. These would mimic $T$-$\bar T$ mixing
effect, except that $T$ mesons do not even form.
| [
{
"created": "Fri, 26 Apr 1996 20:11:33 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Hou",
"George Wei-Shu",
"",
"National Taiwan University"
]
] | We discuss the possibility and likelihood that one may observe {\it like sign} top quark pair production at the Linear Collider. In general two Higgs models, flavor changing couplings involving top quark could be quite sizable. Exotic neutral Higgs bosons may decay dominantly via $t\bar c$ or $\bar tc$ channels. At the linear collider, $e^+e^- \to h^0A^0$ or $H^0A^0$ production processes could lead to $b\bar bt\bar c$, $W^+W^-t\bar c$ or $tt\bar c\bar c$ (or $\bar t\bar tcc$) final states. These would mimic $T$-$\bar T$ mixing effect, except that $T$ mesons do not even form. |
2002.03013 | Howard Baer | Howard Baer, Vernon Barger, Shadman Salam, Dibyashree Sengupta and
Kuver Sinha | Midi-review: Status of weak scale supersymmetry after LHC Run 2 and
ton-scale noble liquid WIMP searches | 47 pages; version 2 includes typo fixes and some added discussion;
version 3 contains minor re-wording on weak scale limits from Agrawal et al | null | 10.1140/epjst/e2020-000020-x | OU-HEP-191231 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | While LHC has discovered a very Standard Model-like Higgs boson of mass m_h~
125 GeV, no solid signal for physics beyond the Standard Model has emerged so
far at LHC or at WIMP seach experiments. For the case of weak scale
supersymmetry (SUSY), LHC has found rather generally that gluinos are beyond
about 2.2 TeV whilst top squark must lie beyond 1.1 TeV. These limits
contradict older simplistic notions of naturalness that emerged in the
1980s-1990s, leading to the rather pessimistic view that SUSY is now excluded
except for perhaps some remaining narrow corners of parameter space. Yet, this
picture ignores several important developments in SUSY/string theory that
emerged in the 21st century: 1. the emergence of the string theory landscape
and its solution to the cosmological constant problem, 2. a more nuanced view
of naturalness including the notion of "stringy naturalness", 3. the emergence
of anomaly-free discrete R-symmetries and their connection to R-parity,
Peccei-Quinn symmetry, the SUSY mu problem and proton decay and 4. the
importance of including a solution to the strong CP problem. Rather general
considerations from the string theory landscape favor large values of soft
terms, subject to the vacuum selection criteria that electroweak symmetry is
properly broken (no CCB minima) and the resulting magnitude of the weak scale
is not too far from our measured value. Then stringy naturalness predicts a
Higgs mass m_h~ 125 GeV whilst sparticle masses are typically lifted beyond
present LHC bounds. In light of these refinements in theory perspective
confronted by LHC and dark matter search results, we review the most likely
LHC, ILC and dark matter signatures that are expected to arise from weak scale
SUSY as we understand it today.
| [
{
"created": "Fri, 7 Feb 2020 21:15:57 GMT",
"version": "v1"
},
{
"created": "Thu, 28 May 2020 18:27:54 GMT",
"version": "v2"
},
{
"created": "Tue, 10 Nov 2020 16:35:08 GMT",
"version": "v3"
}
] | 2020-12-30 | [
[
"Baer",
"Howard",
""
],
[
"Barger",
"Vernon",
""
],
[
"Salam",
"Shadman",
""
],
[
"Sengupta",
"Dibyashree",
""
],
[
"Sinha",
"Kuver",
""
]
] | While LHC has discovered a very Standard Model-like Higgs boson of mass m_h~ 125 GeV, no solid signal for physics beyond the Standard Model has emerged so far at LHC or at WIMP seach experiments. For the case of weak scale supersymmetry (SUSY), LHC has found rather generally that gluinos are beyond about 2.2 TeV whilst top squark must lie beyond 1.1 TeV. These limits contradict older simplistic notions of naturalness that emerged in the 1980s-1990s, leading to the rather pessimistic view that SUSY is now excluded except for perhaps some remaining narrow corners of parameter space. Yet, this picture ignores several important developments in SUSY/string theory that emerged in the 21st century: 1. the emergence of the string theory landscape and its solution to the cosmological constant problem, 2. a more nuanced view of naturalness including the notion of "stringy naturalness", 3. the emergence of anomaly-free discrete R-symmetries and their connection to R-parity, Peccei-Quinn symmetry, the SUSY mu problem and proton decay and 4. the importance of including a solution to the strong CP problem. Rather general considerations from the string theory landscape favor large values of soft terms, subject to the vacuum selection criteria that electroweak symmetry is properly broken (no CCB minima) and the resulting magnitude of the weak scale is not too far from our measured value. Then stringy naturalness predicts a Higgs mass m_h~ 125 GeV whilst sparticle masses are typically lifted beyond present LHC bounds. In light of these refinements in theory perspective confronted by LHC and dark matter search results, we review the most likely LHC, ILC and dark matter signatures that are expected to arise from weak scale SUSY as we understand it today. |
1204.5477 | Alexander Kartavtsev | F. Bezrukov, A. Kartavtsev, M. Lindner | Leptogenesis in models with keV sterile neutrino dark matter | 6 pages, 1 figure | null | 10.1088/0954-3899/40/9/095202 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We analyze leptogenesis in gauge extensions of the Standard Model with keV
sterile neutrino dark matter. We find that both the observed dark matter
abundance and the correct baryon asymmetry of the Universe can simultaneously
emerge in these models. Both the dark matter abundance and the leptogenesis are
controlled by the out of equilibrium decays of the same heavy right handed
neutrino.
| [
{
"created": "Tue, 24 Apr 2012 20:00:03 GMT",
"version": "v1"
},
{
"created": "Wed, 31 Jul 2013 15:29:11 GMT",
"version": "v2"
}
] | 2015-06-04 | [
[
"Bezrukov",
"F.",
""
],
[
"Kartavtsev",
"A.",
""
],
[
"Lindner",
"M.",
""
]
] | We analyze leptogenesis in gauge extensions of the Standard Model with keV sterile neutrino dark matter. We find that both the observed dark matter abundance and the correct baryon asymmetry of the Universe can simultaneously emerge in these models. Both the dark matter abundance and the leptogenesis are controlled by the out of equilibrium decays of the same heavy right handed neutrino. |
0905.2097 | Neda Sadooghi | Neda Sadooghi | Chiral MHD description of a perfect magnetized QGP using the effective
NJL model in a strong magnetic field | 40 pages, 9 figures | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | To study the effect of a strong magnetic field $B$ on the sound velocity
$v_{s}$ of plane waves propagating in a strongly magnetized quark-gluon plasma
(QGP), a chiral magnetohydrodynamical (MHD) description of a perfect
(non-dissipative) QGP exhibiting dynamical chiral symmetry breaking (D$\chi$SB)
is developed using the effective action of the Nambu-Jona-Lasinio (NJL) model
of QCD at finite temperature, finite baryon chemical potential and in the
presence of a strong magnetic field. Here, the D$\chi$SB arises due to the
phenomenon of magnetic catalysis. Apart from an interesting frequency
dependence, for plane waves propagating in the transverse or longitudinal
direction with respect to the $B$ field, the sound velocity is anisotropic and
depends on the angle between the corresponding wave vectors and the direction
of the $B$ field. Moreover, for plane waves propagating in the transverse
(longitudinal) direction to the external $B$ field, the sound velocity has a
maximum (minimum) at $T<T_{c}$, reaches a local minimum (maximum) at $T\sim
T_{c}$ and remains constant at $T\gtrsim T_{c}$. Here, $T_{c}$ is the critical
temperature of the chiral phase transition. Thus, the constant value $v_{s}\sim
1.5 c_{s}$ at $T \gtrsim T_{c}$ turns out to be a lower (upper) bound for waves
propagating in the transverse (longitudinal) direction with respect to the
external $B$ field. Here, $c_{s}=1/\sqrt{3}$ is the sound velocity in an ideal
gas.
| [
{
"created": "Wed, 13 May 2009 18:20:16 GMT",
"version": "v1"
}
] | 2009-05-14 | [
[
"Sadooghi",
"Neda",
""
]
] | To study the effect of a strong magnetic field $B$ on the sound velocity $v_{s}$ of plane waves propagating in a strongly magnetized quark-gluon plasma (QGP), a chiral magnetohydrodynamical (MHD) description of a perfect (non-dissipative) QGP exhibiting dynamical chiral symmetry breaking (D$\chi$SB) is developed using the effective action of the Nambu-Jona-Lasinio (NJL) model of QCD at finite temperature, finite baryon chemical potential and in the presence of a strong magnetic field. Here, the D$\chi$SB arises due to the phenomenon of magnetic catalysis. Apart from an interesting frequency dependence, for plane waves propagating in the transverse or longitudinal direction with respect to the $B$ field, the sound velocity is anisotropic and depends on the angle between the corresponding wave vectors and the direction of the $B$ field. Moreover, for plane waves propagating in the transverse (longitudinal) direction to the external $B$ field, the sound velocity has a maximum (minimum) at $T<T_{c}$, reaches a local minimum (maximum) at $T\sim T_{c}$ and remains constant at $T\gtrsim T_{c}$. Here, $T_{c}$ is the critical temperature of the chiral phase transition. Thus, the constant value $v_{s}\sim 1.5 c_{s}$ at $T \gtrsim T_{c}$ turns out to be a lower (upper) bound for waves propagating in the transverse (longitudinal) direction with respect to the external $B$ field. Here, $c_{s}=1/\sqrt{3}$ is the sound velocity in an ideal gas. |
2108.04285 | Drew Backhouse | Drew Backhouse | The Phenomenological Motivation of Axions: A Review | 42 pages | null | null | null | hep-ph | http://creativecommons.org/licenses/by/4.0/ | Setting aside anthropic arguments, there is no reason for CP symmetry to be
obeyed within the theory of quantum chromodynamics. However, no such violation
of CP symmetry has ever been observed in a strongly interacting experiment.
This is known as the strong CP problem which, in its simplest manifestations,
can be quantitatively formulated via a calculation of the pion masses and the
neutron electric dipole moment. The former yields a larger mass for the neutral
pion than its charged counterparts, the latter yields a far larger result than
is experimentally measured, where in both cases the discrepancies are
parameterised by the physical quantity $\bar{\theta}$. The strong CP problem
can be solved via the inclusion of a new particle, the axion, which dynamically
sets $\bar{\theta}$ to zero, eliminating these two manifestations. Thus,
experimental searches for such a particle are an active field of research. This
dissertation acts as a review of the aforementioned concepts.
| [
{
"created": "Mon, 9 Aug 2021 18:21:29 GMT",
"version": "v1"
}
] | 2021-08-11 | [
[
"Backhouse",
"Drew",
""
]
] | Setting aside anthropic arguments, there is no reason for CP symmetry to be obeyed within the theory of quantum chromodynamics. However, no such violation of CP symmetry has ever been observed in a strongly interacting experiment. This is known as the strong CP problem which, in its simplest manifestations, can be quantitatively formulated via a calculation of the pion masses and the neutron electric dipole moment. The former yields a larger mass for the neutral pion than its charged counterparts, the latter yields a far larger result than is experimentally measured, where in both cases the discrepancies are parameterised by the physical quantity $\bar{\theta}$. The strong CP problem can be solved via the inclusion of a new particle, the axion, which dynamically sets $\bar{\theta}$ to zero, eliminating these two manifestations. Thus, experimental searches for such a particle are an active field of research. This dissertation acts as a review of the aforementioned concepts. |
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