id stringlengths 9 14 | submitter stringlengths 1 56 ⌀ | authors stringlengths 5 7.68k | title stringlengths 3 299 | comments stringlengths 1 1.15k ⌀ | journal-ref stringlengths 9 298 ⌀ | doi stringlengths 12 97 ⌀ | report-no stringlengths 3 341 ⌀ | categories stringclasses 869 values | license stringclasses 9 values | orig_abstract stringlengths 16 2.44k | versions listlengths 1 39 | update_date stringlengths 10 10 | authors_parsed listlengths 1 565 | abstract stringlengths 13 2.44k |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
hep-ph/0101082 | Karsten Tabelow | K. Tabelow | Self-Organized Criticality in Gluon Systems and its Consequences | Presented at 30th International Symposium on Multiparticle Dynamics
(ISMD 2000), Tihany, Lake Balaton, Hungary, 9-15 Oct 2000 | null | null | null | hep-ph | null | It is pointed out, that color-singlet gluon clusters can be formed in hadrons
as a consequence of self-organized criticality (SOC) in systems of interacting
soft gluons, and that the properties of such spatiotemporal complexities can be
probed experimentally by examing inelastic diffractive scattering. Theoretical
arguments and experimental evidence supporting the proposed picture are
presented. As a consequence of the space-time properties of the color-singlet
gluon clusters due to SOC in gluon systems, a simple analytical formula for the
differential cross section for inelastic diffractive hadron-hadron scattering
can be derived. The obtained results are in good agreement with the existing
data. Furthermore, it is shown that meson radii can be extracted from inelastic
diffractive scattering experiments. The obtained results for pion and kaon
charge radii are compared with those determined in meson form factor
measurements.
| [
{
"created": "Tue, 9 Jan 2001 16:51:05 GMT",
"version": "v1"
},
{
"created": "Mon, 29 Jan 2001 16:12:58 GMT",
"version": "v2"
}
] | 2007-05-23 | [
[
"Tabelow",
"K.",
""
]
] | It is pointed out, that color-singlet gluon clusters can be formed in hadrons as a consequence of self-organized criticality (SOC) in systems of interacting soft gluons, and that the properties of such spatiotemporal complexities can be probed experimentally by examing inelastic diffractive scattering. Theoretical arguments and experimental evidence supporting the proposed picture are presented. As a consequence of the space-time properties of the color-singlet gluon clusters due to SOC in gluon systems, a simple analytical formula for the differential cross section for inelastic diffractive hadron-hadron scattering can be derived. The obtained results are in good agreement with the existing data. Furthermore, it is shown that meson radii can be extracted from inelastic diffractive scattering experiments. The obtained results for pion and kaon charge radii are compared with those determined in meson form factor measurements. |
2010.09451 | Valentin Hirschi Dr | Matteo Becchetti, Roberto Bonciani, Vittorio Del Duca, Valentin
Hirschi, Francesco Moriello, and Armin Schweitzer | NLO Corrections to Light-Quark Mixed QCD-EW Contributions to Higgs
Production | 7 pages, 4 figures | Phys. Rev. D 103, 054037 (2021) | 10.1103/PhysRevD.103.054037 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present for the first time the exact NLO QCD corrections to the
light-quark part of the mixed QCD-EW contributions to Higgs production via
gluon fusion at LHC13, with exact EW-boson mass dependence. The relevant
two-loop real-emission matrix element is computed using a dynamic
one-dimensional series expansion strategy whose stability and speed allows for
a numerical phase-space integration using local IR subtraction counterterms.
For $\mu_R=\mu_F=M_H$, we find:
\begin{equation}\sigma^{(\alpha_s^2\alpha^2+\alpha_s^3\alpha^2)}_{g
g\rightarrow H+X} = 1.467(2)^{\;+18.7\%}_{\;-14.6\%}\;(\mu_R\;\text{var.})\;\pm
2\%\;(\text{PDF}) \ \textrm{pb},\end{equation} which we use to provide the best
result including an estimate of suppressed contributions:
\begin{equation}\sigma^{(\text{EW},\textrm{best})}_{p p\rightarrow H+X} = 2.11
\pm 0.28 \ (\textrm{theory}) \ \mathrm{pb}.\end{equation}
| [
{
"created": "Mon, 19 Oct 2020 13:00:01 GMT",
"version": "v1"
}
] | 2021-03-31 | [
[
"Becchetti",
"Matteo",
""
],
[
"Bonciani",
"Roberto",
""
],
[
"Del Duca",
"Vittorio",
""
],
[
"Hirschi",
"Valentin",
""
],
[
"Moriello",
"Francesco",
""
],
[
"Schweitzer",
"Armin",
""
]
] | We present for the first time the exact NLO QCD corrections to the light-quark part of the mixed QCD-EW contributions to Higgs production via gluon fusion at LHC13, with exact EW-boson mass dependence. The relevant two-loop real-emission matrix element is computed using a dynamic one-dimensional series expansion strategy whose stability and speed allows for a numerical phase-space integration using local IR subtraction counterterms. For $\mu_R=\mu_F=M_H$, we find: \begin{equation}\sigma^{(\alpha_s^2\alpha^2+\alpha_s^3\alpha^2)}_{g g\rightarrow H+X} = 1.467(2)^{\;+18.7\%}_{\;-14.6\%}\;(\mu_R\;\text{var.})\;\pm 2\%\;(\text{PDF}) \ \textrm{pb},\end{equation} which we use to provide the best result including an estimate of suppressed contributions: \begin{equation}\sigma^{(\text{EW},\textrm{best})}_{p p\rightarrow H+X} = 2.11 \pm 0.28 \ (\textrm{theory}) \ \mathrm{pb}.\end{equation} |
hep-ph/0003021 | Urs Wiedemann | Urs Achim Wiedemann | Transverse Dynamics of Hard Partons in Nuclear Media and the QCD Dipole | 23 pages, LaTeX, 12 eps-figures included, typos corrected, discussion
extended, to appear in NPB | Nucl.Phys. B582 (2000) 409-450 | 10.1016/S0550-3213(00)00286-8 | null | hep-ph nucl-th | null | We derive the non-abelian generalization of the Furry approximation which
describes the transverse dynamical evolution of a hard projectile parton inside
a spatially extended colour target field. This provides a unified starting
point for the target rest frame description of the nuclear dependence of a
large class of observables. For the case of the virtual gamma -> q-qbar
photoabsorption cross section, we investigate then in detail under which
conditions the nuclear dependence encoded in the Furry wavefunctions can be
parametrized by a q-qbar QCD dipole cross section. The important condition is
colour triviality, i.e., the property that for arbitrary N-fold rescattering
contributions the only non-vanishing colour trace is N_c C_F^N. We give proofs
for the colour triviality of the inelastic, diffractive and total
photoabsorption cross section measured inclusively or with one jet resolved in
the final state. Also, we list examples for which colour interference effects
remain. Colour triviality allows us to write the gamma -> q qbar contribution
to the DIS nuclear structure function F_2 for small Bjorken x in terms of a
path integral which describes the transverse size evolution of the q-qbar pair
in the nuclear colour field. This expression reduces in an opacity expansion to
the N=1 result of Nikolaev and Zakharov, and in the eikonal approximation to
the Glauber-type rescattering formulas first derived by Mueller. In the
harmonic oscillator approximation of the path integral, we quantify deviations
from the eikonal limit. Their onset is characterized by the scales L/l_f and
E_t L which relate the longitudinal extension L of the nuclear target to the
coherence length l_f and the total transverse energy E_t accumulated by the
q-qbar pair.
| [
{
"created": "Fri, 3 Mar 2000 10:26:41 GMT",
"version": "v1"
},
{
"created": "Thu, 15 Jun 2000 09:33:49 GMT",
"version": "v2"
}
] | 2009-10-31 | [
[
"Wiedemann",
"Urs Achim",
""
]
] | We derive the non-abelian generalization of the Furry approximation which describes the transverse dynamical evolution of a hard projectile parton inside a spatially extended colour target field. This provides a unified starting point for the target rest frame description of the nuclear dependence of a large class of observables. For the case of the virtual gamma -> q-qbar photoabsorption cross section, we investigate then in detail under which conditions the nuclear dependence encoded in the Furry wavefunctions can be parametrized by a q-qbar QCD dipole cross section. The important condition is colour triviality, i.e., the property that for arbitrary N-fold rescattering contributions the only non-vanishing colour trace is N_c C_F^N. We give proofs for the colour triviality of the inelastic, diffractive and total photoabsorption cross section measured inclusively or with one jet resolved in the final state. Also, we list examples for which colour interference effects remain. Colour triviality allows us to write the gamma -> q qbar contribution to the DIS nuclear structure function F_2 for small Bjorken x in terms of a path integral which describes the transverse size evolution of the q-qbar pair in the nuclear colour field. This expression reduces in an opacity expansion to the N=1 result of Nikolaev and Zakharov, and in the eikonal approximation to the Glauber-type rescattering formulas first derived by Mueller. In the harmonic oscillator approximation of the path integral, we quantify deviations from the eikonal limit. Their onset is characterized by the scales L/l_f and E_t L which relate the longitudinal extension L of the nuclear target to the coherence length l_f and the total transverse energy E_t accumulated by the q-qbar pair. |
0808.0874 | Lance Labun | Lance Labun and Johann Rafelski | Vacuum Decay Time in Strong External Fields | 4 pages, 2 figures; improved representation of eq. 12, improved
figures, added references, improved introductory material, and corrected
typos | Phys.Rev.D79:057901,2009 | 10.1103/PhysRevD.79.057901 | null | hep-ph nucl-th physics.optics | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We consider dynamics of vacuum decay and particle production in the context
of short pulse laser experiments. We identify and evaluate the invariant
"materialization time," $\tau$, the timescale for the conversion of an
electromagnetic field energy into particles, and we compare to the laser
related time scales.
| [
{
"created": "Wed, 6 Aug 2008 16:23:54 GMT",
"version": "v1"
},
{
"created": "Wed, 22 Oct 2008 17:41:41 GMT",
"version": "v2"
}
] | 2009-03-12 | [
[
"Labun",
"Lance",
""
],
[
"Rafelski",
"Johann",
""
]
] | We consider dynamics of vacuum decay and particle production in the context of short pulse laser experiments. We identify and evaluate the invariant "materialization time," $\tau$, the timescale for the conversion of an electromagnetic field energy into particles, and we compare to the laser related time scales. |
hep-ph/0102125 | Alexander Dolgov | A.D. Dolgov | Neutrino oscillations in the early universe. Resonant case | 25 pages, latex | Nucl.Phys. B610 (2001) 411-429 | 10.1016/S0550-3213(01)00323-6 | null | hep-ph | null | Lepton asymmetry generated in the early universe by neutrino oscillations
into sterile partners is calculated. Kinetic equations are analytically reduced
to a simple form that permits an easy numerical treatment. Asymptotic values of
the asymmetry are at the level of 0.2-0.3 and are reasonably close to those
obtained by other groups, though the approach to asymptotics in some cases is
noticeably slower. No chaoticity is observed.
| [
{
"created": "Sat, 10 Feb 2001 18:16:03 GMT",
"version": "v1"
}
] | 2009-11-07 | [
[
"Dolgov",
"A. D.",
""
]
] | Lepton asymmetry generated in the early universe by neutrino oscillations into sterile partners is calculated. Kinetic equations are analytically reduced to a simple form that permits an easy numerical treatment. Asymptotic values of the asymmetry are at the level of 0.2-0.3 and are reasonably close to those obtained by other groups, though the approach to asymptotics in some cases is noticeably slower. No chaoticity is observed. |
1503.06470 | Dean Robinson | Marco Farina, Yuval Grossman and Dean J. Robinson | Probing CP Violation in $h \to Z\gamma$ with Background Interference | 20 pages, 4 figures | Phys. Rev. D 92, 073007 (2015) | 10.1103/PhysRevD.92.073007 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We show that the parity of the $h Z\gamma$ vertex can be probed by
interference between the gluon fusion Higgs production, $gg \to h \to \gamma Z
\to \gamma \ell^+\ell^-$, and the background, $gg \to \gamma Z \to \gamma
\ell^+\ell^-$, amplitudes. In the presence of a parity violating $hZ\gamma$
vertex, this interference alters the kinematic distribution of the leptons and
photon compared to Standard Model (SM) expectations. For a Higgs with SM-sized
width and couplings, we find that the size of the effect enters at most at the
$10^{-2}$ level. Such a small effect cannot be seen at the LHC, even with
futuristic high luminosities. Should there exist other broader scalar particles
with larger production cross-section times branching ratio to $Z\gamma$, then
the parity structure of their $Z\gamma$ couplings can be probed with this
technique.
| [
{
"created": "Sun, 22 Mar 2015 19:52:25 GMT",
"version": "v1"
}
] | 2015-10-14 | [
[
"Farina",
"Marco",
""
],
[
"Grossman",
"Yuval",
""
],
[
"Robinson",
"Dean J.",
""
]
] | We show that the parity of the $h Z\gamma$ vertex can be probed by interference between the gluon fusion Higgs production, $gg \to h \to \gamma Z \to \gamma \ell^+\ell^-$, and the background, $gg \to \gamma Z \to \gamma \ell^+\ell^-$, amplitudes. In the presence of a parity violating $hZ\gamma$ vertex, this interference alters the kinematic distribution of the leptons and photon compared to Standard Model (SM) expectations. For a Higgs with SM-sized width and couplings, we find that the size of the effect enters at most at the $10^{-2}$ level. Such a small effect cannot be seen at the LHC, even with futuristic high luminosities. Should there exist other broader scalar particles with larger production cross-section times branching ratio to $Z\gamma$, then the parity structure of their $Z\gamma$ couplings can be probed with this technique. |
hep-ph/0406047 | Zhi-Zhong Xing | Zhi-zhong Xing | Universal Neutrino Mass Hierarchy and Cosmological Baryon Number
Asymmetry | RevTex 8 pages (1 PS figure included). Fig. 1 changed. Accepted for
publication in PRD | Phys.Rev. D70 (2004) 071302 | 10.1103/PhysRevD.70.071302 | null | hep-ph astro-ph | null | We conjecture that three light Majorana neutrinos and their right-handed
counterparts may have a universal geometric mass hierarchy. Incorporating this
phenomenological conjecture with the Fritzsch texture of lepton mass matrices
in a simple seesaw mechanism, we show that it is possible to simultaneously
account for current neutrino oscillation data and the cosmological baryon
number asymmetry via leptogenesis.
| [
{
"created": "Fri, 4 Jun 2004 08:07:47 GMT",
"version": "v1"
},
{
"created": "Mon, 7 Jun 2004 19:50:07 GMT",
"version": "v2"
},
{
"created": "Wed, 29 Sep 2004 02:42:16 GMT",
"version": "v3"
}
] | 2009-11-10 | [
[
"Xing",
"Zhi-zhong",
""
]
] | We conjecture that three light Majorana neutrinos and their right-handed counterparts may have a universal geometric mass hierarchy. Incorporating this phenomenological conjecture with the Fritzsch texture of lepton mass matrices in a simple seesaw mechanism, we show that it is possible to simultaneously account for current neutrino oscillation data and the cosmological baryon number asymmetry via leptogenesis. |
1805.06049 | Pat Scott | Pat Scott (for the GAMBIT Collaboration) | Global analyses of supersymmetry with GAMBIT | 4 pages, 3 figures, proceedings of invited contribution to Rencontres
de Moriond QCD 2018 | null | null | gambit-proceedings-2018 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | I provide a brief summary of the status of supersymmetric models with
parameters defined at either the unification or weak scale, based on global
fits using the GAMBIT framework.
| [
{
"created": "Tue, 15 May 2018 22:16:36 GMT",
"version": "v1"
}
] | 2020-08-19 | [
[
"Scott",
"Pat",
"",
"for the GAMBIT Collaboration"
]
] | I provide a brief summary of the status of supersymmetric models with parameters defined at either the unification or weak scale, based on global fits using the GAMBIT framework. |
1701.08780 | Felix Kahlhoefer | Michael Duerr, Alexander Grohsjean, Felix Kahlhoefer, Bjoern Penning,
Kai Schmidt-Hoberg, Christian Schwanenberger | Hunting the dark Higgs | 22 pages, 7 figures; v2: references added, matches published version | JHEP 1704 (2017) 143 | 10.1007/JHEP04(2017)143 | DESY-17-016 | hep-ph hep-ex | http://creativecommons.org/licenses/by/4.0/ | We discuss a novel signature of dark matter production at the LHC resulting
from the emission of an additional Higgs boson in the dark sector. The presence
of such a dark Higgs boson is motivated simultaneously by the need to generate
the masses of the particles in the dark sector and the possibility to relax
constraints from the dark matter relic abundance by opening up a new
annihilation channel. If the dark Higgs boson decays into Standard Model states
via a small mixing with the Standard Model Higgs boson, one obtains
characteristic large-radius jets in association with missing transverse
momentum that can be used to efficiently discriminate signal from backgrounds.
We present the sensitivities achievable in LHC searches for dark Higgs bosons
with already collected data and demonstrate that such searches can probe large
regions of parameter space that are inaccessible to conventional mono-jet or
di-jet searches.
| [
{
"created": "Mon, 30 Jan 2017 19:01:21 GMT",
"version": "v1"
},
{
"created": "Tue, 9 May 2017 07:47:28 GMT",
"version": "v2"
}
] | 2017-05-10 | [
[
"Duerr",
"Michael",
""
],
[
"Grohsjean",
"Alexander",
""
],
[
"Kahlhoefer",
"Felix",
""
],
[
"Penning",
"Bjoern",
""
],
[
"Schmidt-Hoberg",
"Kai",
""
],
[
"Schwanenberger",
"Christian",
""
]
] | We discuss a novel signature of dark matter production at the LHC resulting from the emission of an additional Higgs boson in the dark sector. The presence of such a dark Higgs boson is motivated simultaneously by the need to generate the masses of the particles in the dark sector and the possibility to relax constraints from the dark matter relic abundance by opening up a new annihilation channel. If the dark Higgs boson decays into Standard Model states via a small mixing with the Standard Model Higgs boson, one obtains characteristic large-radius jets in association with missing transverse momentum that can be used to efficiently discriminate signal from backgrounds. We present the sensitivities achievable in LHC searches for dark Higgs bosons with already collected data and demonstrate that such searches can probe large regions of parameter space that are inaccessible to conventional mono-jet or di-jet searches. |
hep-ph/9505325 | Katsuhiko Suzuki | Katsuhiko Suzuki | Pion structure function in nuclear medium | 16 pages (LaTeX), 5 figures are available as uuencoded PS files upon
request | Phys.Lett. B368 (1996) 1-6 | 10.1016/0370-2693(95)01462-4 | TMU-NT950501 | hep-ph | null | We study the pion structure function in nuclear medium using the Nambu and
Jona-Lasinio model, and its implication for the nuclear pion enhancement of the
sea quark distribution in nuclei. By using the operator product expansion,
medium effect of the nuclear matter is incorporated in calculations of the
twist-2 operators. We find density dependence of the pion structure function is
rather weak around the nuclear matter density. We also discuss how the medium
modification of the pion structure affects the sea quark enhancement in the
nucleus.
| [
{
"created": "Wed, 17 May 1995 11:10:47 GMT",
"version": "v1"
}
] | 2009-10-28 | [
[
"Suzuki",
"Katsuhiko",
""
]
] | We study the pion structure function in nuclear medium using the Nambu and Jona-Lasinio model, and its implication for the nuclear pion enhancement of the sea quark distribution in nuclei. By using the operator product expansion, medium effect of the nuclear matter is incorporated in calculations of the twist-2 operators. We find density dependence of the pion structure function is rather weak around the nuclear matter density. We also discuss how the medium modification of the pion structure affects the sea quark enhancement in the nucleus. |
hep-ph/0508092 | Peter Uwer | J.H. Kuhn, A. Scharf, P.Uwer | Electroweak corrections to top-quark pair production in quark--antiquark
annihilation | null | Eur.Phys.J.C45:139-150,2006 | 10.1140/epjc/s2005-02423-6 | CERN-PH-TH/2005-145, TTP05-12, SFB/CPP-05-36 | hep-ph | null | Top-quark physics plays an important role at hadron colliders such as the
Tevatron at Fermilab or the LHC at CERN. Given the planned precision at these
colliders, precise theoretical predictions are required. In this paper we
present the complete electroweak corrections to QCD-induced top-quark pair
production in quark--antiquark annihilation. In particular we provide compact
analytic expressions for the differential partonic cross section, which will be
useful for further theoretical investigations.
| [
{
"created": "Mon, 8 Aug 2005 08:01:15 GMT",
"version": "v1"
}
] | 2009-01-07 | [
[
"Kuhn",
"J. H.",
""
],
[
"Scharf",
"A.",
""
],
[
"Uwer",
"P.",
""
]
] | Top-quark physics plays an important role at hadron colliders such as the Tevatron at Fermilab or the LHC at CERN. Given the planned precision at these colliders, precise theoretical predictions are required. In this paper we present the complete electroweak corrections to QCD-induced top-quark pair production in quark--antiquark annihilation. In particular we provide compact analytic expressions for the differential partonic cross section, which will be useful for further theoretical investigations. |
hep-ph/9407392 | B. de Carlos | B. de Carlos and M. Moretti | Soft Supersymmetry Breaking from Gaugino Condensation | Latex, 18 pages, 4 postcript figures appended at the end (they can be
inserted in the text using the macro epsf.tex), OUTP-94-16P | Phys.Lett. B341 (1995) 302-312 | 10.1016/0370-2693(95)80008-L | null | hep-ph | null | We study the structure of soft breaking terms in the context of a gaugino
condensation scenario. Assuming that the Supergravity Lagrangian is the correct
quantum field theory limit, at some momentum scale $\mu_{UV}$, of a more
fundamental one, we demonstrate that the correct result is obtained simply by
substituting, in the tree level Supergravity Lagrangian, $\lambda \lambda$ (the
gaugino condensate) by its vacuum expectation value $\Lambda^3$. In string
inspired scenarios this implies, in particular, that the scalar masses are
vanishing at the string tree-level and receive a contribution, at the one loop
level, which is proportional to the Green Schwarz coefficient $\delta_{GS}$.
Our results do not agree with the ones obtained in the effective Lagrangian
approach. We study in detail the origin of this discrepancy, and we argue that
the use of the supertrace anomaly to determine the effective theory for the
condensate does not fix its gravitational interactions, leaving the soft
breaking terms and the vacua of the theory unspecified.
| [
{
"created": "Thu, 28 Jul 1994 10:03:36 GMT",
"version": "v1"
}
] | 2015-06-25 | [
[
"de Carlos",
"B.",
""
],
[
"Moretti",
"M.",
""
]
] | We study the structure of soft breaking terms in the context of a gaugino condensation scenario. Assuming that the Supergravity Lagrangian is the correct quantum field theory limit, at some momentum scale $\mu_{UV}$, of a more fundamental one, we demonstrate that the correct result is obtained simply by substituting, in the tree level Supergravity Lagrangian, $\lambda \lambda$ (the gaugino condensate) by its vacuum expectation value $\Lambda^3$. In string inspired scenarios this implies, in particular, that the scalar masses are vanishing at the string tree-level and receive a contribution, at the one loop level, which is proportional to the Green Schwarz coefficient $\delta_{GS}$. Our results do not agree with the ones obtained in the effective Lagrangian approach. We study in detail the origin of this discrepancy, and we argue that the use of the supertrace anomaly to determine the effective theory for the condensate does not fix its gravitational interactions, leaving the soft breaking terms and the vacua of the theory unspecified. |
1203.4381 | Zhi Hui Guo | Zhi-Hui Guo, J. A. Oller and J. Ruiz de Elvira | Chiral dynamics in U(3) unitary chiral perturbation theory | To match the version accepted by Phys.Lett.B | null | 10.1016/j.physletb.2012.05.021 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We perform a complete one-loop calculation of meson-meson scattering, and of
the scalar and pseudoscalar form factors in U(3) chiral perturbation theory
with the inclusion of explicit resonance fields. This effective field theory
takes into account the low-energy effects of the QCD U_A(1) anomaly explicitly
in the dynamics. The calculations are supplied by non-perturbative
unitarization techniques that provide the final results for the meson-meson
scattering partial waves and the scalar form factors considered. We present
thorough analyses on the scattering data, resonance spectroscopy, spectral
functions, Weinberg-like sum rules and semi-local duality. The last two
requirements establish relations between the scalar spectrum with the
pseudoscalar and vector ones, respectively. The Nc extrapolation of the various
quantities is studied as well. The fulfillment of all these non-trivial aspects
of the QCD dynamics by our results gives a strong support to the emerging
picture for the scalar dynamics and its related spectrum.
| [
{
"created": "Tue, 20 Mar 2012 10:42:44 GMT",
"version": "v1"
},
{
"created": "Tue, 15 May 2012 13:32:51 GMT",
"version": "v2"
}
] | 2015-06-04 | [
[
"Guo",
"Zhi-Hui",
""
],
[
"Oller",
"J. A.",
""
],
[
"de Elvira",
"J. Ruiz",
""
]
] | We perform a complete one-loop calculation of meson-meson scattering, and of the scalar and pseudoscalar form factors in U(3) chiral perturbation theory with the inclusion of explicit resonance fields. This effective field theory takes into account the low-energy effects of the QCD U_A(1) anomaly explicitly in the dynamics. The calculations are supplied by non-perturbative unitarization techniques that provide the final results for the meson-meson scattering partial waves and the scalar form factors considered. We present thorough analyses on the scattering data, resonance spectroscopy, spectral functions, Weinberg-like sum rules and semi-local duality. The last two requirements establish relations between the scalar spectrum with the pseudoscalar and vector ones, respectively. The Nc extrapolation of the various quantities is studied as well. The fulfillment of all these non-trivial aspects of the QCD dynamics by our results gives a strong support to the emerging picture for the scalar dynamics and its related spectrum. |
1012.0853 | Cristiano Germani | Cristiano Germani (ASC, Munich) and Alex Kehagias (NTUA, Athens) | UV-Protected Inflation | 5 pages; v3: Minkowski limit of the "strong coupling scale"
corrected; results unchanged; accepted in Phys. Rev. Lett. 2011 | Phys.Rev.Lett.106:161302,2011 | 10.1103/PhysRevLett.106.161302 | LMU-ASC 101/10 | hep-ph astro-ph.CO gr-qc hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In Natural Inflation, the Inflaton is a pseudo-Nambu-Goldstone boson which
acquires a mass by explicit breaking of a global shift symmetry at scale f. In
this case, for small field values, the potential is flat and stable under
radiative corrections. Nevertheless, slow roll conditions enforce f>>M_p making
the validity of the whole scenario questionable. In this letter, we show that a
coupling of the Inflaton kinetic term to the Einstein tensor allows f<<M_p by
enhancing the gravitational friction acting on the Inflaton during inflation.
This new unique interaction, a) keeps the theory perturbative in the whole
inflationary trajectory, b) preserves the tree-level shift invariance of the
pseudo-Nambu-Goldstone Boson and c) avoids the introduction of any new degrees
of freedom with respect the standard Natural Inflation.
| [
{
"created": "Fri, 3 Dec 2010 21:22:28 GMT",
"version": "v1"
},
{
"created": "Mon, 13 Dec 2010 16:18:43 GMT",
"version": "v2"
},
{
"created": "Fri, 1 Apr 2011 21:44:02 GMT",
"version": "v3"
}
] | 2011-05-09 | [
[
"Germani",
"Cristiano",
"",
"ASC, Munich"
],
[
"Kehagias",
"Alex",
"",
"NTUA, Athens"
]
] | In Natural Inflation, the Inflaton is a pseudo-Nambu-Goldstone boson which acquires a mass by explicit breaking of a global shift symmetry at scale f. In this case, for small field values, the potential is flat and stable under radiative corrections. Nevertheless, slow roll conditions enforce f>>M_p making the validity of the whole scenario questionable. In this letter, we show that a coupling of the Inflaton kinetic term to the Einstein tensor allows f<<M_p by enhancing the gravitational friction acting on the Inflaton during inflation. This new unique interaction, a) keeps the theory perturbative in the whole inflationary trajectory, b) preserves the tree-level shift invariance of the pseudo-Nambu-Goldstone Boson and c) avoids the introduction of any new degrees of freedom with respect the standard Natural Inflation. |
1404.2640 | Kunal Kumar | Katy Hartling, Kunal Kumar, Heather E. Logan | The decoupling limit in the Georgi-Machacek model | 40 pages, 12 figures, v2 : typo in Eq. 61 corrected, Reference added,
v3: typos in Eq. A8 line 2 and Eq. 28 corrected, version to be published in
PRD | Phys. Rev. D 90, 015007 (2014) | 10.1103/PhysRevD.90.015007 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study the most general scalar potential of the Georgi-Machacek model,
which adds isospin-triplet scalars to the Standard Model (SM) in a way that
preserves custodial SU(2) symmetry. We show that this model possesses a
decoupling limit, in which the predominantly-triplet states become heavy and
degenerate while the couplings of the remaining light neutral scalar approach
those of the SM Higgs boson. We find that the SM-like Higgs boson couplings to
fermion pairs and gauge boson pairs can deviate from their SM values by
corrections as large as $\mathcal{O}(v^2/M_{\rm new}^2)$, where $v$ is the SM
Higgs vacuum expectation value and $M_{\rm new}$ is the mass scale of the
predominantly-triplet states. In particular, the SM-like Higgs boson couplings
to $W$ and $Z$ boson pairs can decouple much more slowly than in two Higgs
doublet models, in which they deviate from their SM values like
$\mathcal{O}(v^4/M_{\rm new}^4)$. Furthermore, near the decoupling limit the
SM-like Higgs boson couplings to $W$ and $Z$ pairs are always larger than their
SM values, which cannot occur in two Higgs doublet models. As such, a precision
measurement of Higgs couplings to $W$ and $Z$ pairs may provide an effective
method of distinguishing the Georgi-Machacek model from two Higgs doublet
models. Using numerical scans, we show that the coupling deviations can reach
10% for $M_{\rm new}$ as large as 800~GeV.
| [
{
"created": "Wed, 9 Apr 2014 21:50:39 GMT",
"version": "v1"
},
{
"created": "Thu, 24 Apr 2014 17:17:03 GMT",
"version": "v2"
},
{
"created": "Fri, 11 Jul 2014 20:59:50 GMT",
"version": "v3"
}
] | 2014-07-16 | [
[
"Hartling",
"Katy",
""
],
[
"Kumar",
"Kunal",
""
],
[
"Logan",
"Heather E.",
""
]
] | We study the most general scalar potential of the Georgi-Machacek model, which adds isospin-triplet scalars to the Standard Model (SM) in a way that preserves custodial SU(2) symmetry. We show that this model possesses a decoupling limit, in which the predominantly-triplet states become heavy and degenerate while the couplings of the remaining light neutral scalar approach those of the SM Higgs boson. We find that the SM-like Higgs boson couplings to fermion pairs and gauge boson pairs can deviate from their SM values by corrections as large as $\mathcal{O}(v^2/M_{\rm new}^2)$, where $v$ is the SM Higgs vacuum expectation value and $M_{\rm new}$ is the mass scale of the predominantly-triplet states. In particular, the SM-like Higgs boson couplings to $W$ and $Z$ boson pairs can decouple much more slowly than in two Higgs doublet models, in which they deviate from their SM values like $\mathcal{O}(v^4/M_{\rm new}^4)$. Furthermore, near the decoupling limit the SM-like Higgs boson couplings to $W$ and $Z$ pairs are always larger than their SM values, which cannot occur in two Higgs doublet models. As such, a precision measurement of Higgs couplings to $W$ and $Z$ pairs may provide an effective method of distinguishing the Georgi-Machacek model from two Higgs doublet models. Using numerical scans, we show that the coupling deviations can reach 10% for $M_{\rm new}$ as large as 800~GeV. |
2003.12249 | Jiangshan Lan | Jiangshan Lan, Chandan Mondal, Shaoyang Jia, Xingbo Zhao, James P.
Vary | Light Meson Parton Distribution Functions from Basis Light-Front
Quantization and QCD Evolution | Conference: C19-08-16 | Hadron 2019, 581-585 | 10.1142/9789811219313_0099 | null | hep-ph nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We investigate the parton distribution functions (PDFs) of the pion and kaon
from the eigenstates of a light-front effective Hamiltonian in the constituent
quark-antiquark representation suitable for low-momentum scale applications. By
taking these scales as the only free parameters, the valence quark distribution
functions of the pion, after QCD evolving, are consistent with the E615
experiment at Fermilab. In addition, the ratio of the up quark distribution in
the kaon to that in the pion also agrees with the NA3 experimental result at
CERN.
| [
{
"created": "Fri, 27 Mar 2020 06:09:14 GMT",
"version": "v1"
}
] | 2020-09-07 | [
[
"Lan",
"Jiangshan",
""
],
[
"Mondal",
"Chandan",
""
],
[
"Jia",
"Shaoyang",
""
],
[
"Zhao",
"Xingbo",
""
],
[
"Vary",
"James P.",
""
]
] | We investigate the parton distribution functions (PDFs) of the pion and kaon from the eigenstates of a light-front effective Hamiltonian in the constituent quark-antiquark representation suitable for low-momentum scale applications. By taking these scales as the only free parameters, the valence quark distribution functions of the pion, after QCD evolving, are consistent with the E615 experiment at Fermilab. In addition, the ratio of the up quark distribution in the kaon to that in the pion also agrees with the NA3 experimental result at CERN. |
1806.06857 | Joseph Bramante | Amit Bhoonah, Joseph Bramante, Fatemeh Elahi, Sarah Schon | Calorimetric Dark Matter Detection With Galactic Center Gas Clouds | 2 figures, 7 pages | Phys. Rev. Lett. 121, 131101 (2018) | 10.1103/PhysRevLett.121.131101 | null | hep-ph astro-ph.GA | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We demonstrate that dark matter heating of gas clouds hundreds of parsecs
from the Milky Way Galactic center provides a powerful new test of dark matter
interactions. To illustrate, we set a leading bound on nucleon scattering for
10-100 MeV mass dark matter. We also constrain millicharged dark matter models,
including those proposed to match the recent EDGES 21 cm absorption anomaly.
For Galactic center gas clouds, galactic fields' magnetic deflection of
electromagnetically charged dark matter is mitigated, because the magnetic
fields around the Galactic center are poloidal, as opposed to being aligned
parallel to the Milky Way disk. We discuss prospects for detecting dark matter
using a population of Galactic center gas clouds warmed by dark matter.
| [
{
"created": "Mon, 18 Jun 2018 18:00:00 GMT",
"version": "v1"
}
] | 2018-10-03 | [
[
"Bhoonah",
"Amit",
""
],
[
"Bramante",
"Joseph",
""
],
[
"Elahi",
"Fatemeh",
""
],
[
"Schon",
"Sarah",
""
]
] | We demonstrate that dark matter heating of gas clouds hundreds of parsecs from the Milky Way Galactic center provides a powerful new test of dark matter interactions. To illustrate, we set a leading bound on nucleon scattering for 10-100 MeV mass dark matter. We also constrain millicharged dark matter models, including those proposed to match the recent EDGES 21 cm absorption anomaly. For Galactic center gas clouds, galactic fields' magnetic deflection of electromagnetically charged dark matter is mitigated, because the magnetic fields around the Galactic center are poloidal, as opposed to being aligned parallel to the Milky Way disk. We discuss prospects for detecting dark matter using a population of Galactic center gas clouds warmed by dark matter. |
1212.0358 | Jan Uphoff | Jan Uphoff, Oliver Fochler, Zhe Xu, Carsten Greiner | Open heavy flavor and J/psi at RHIC and LHC within a transport model | 4 pages, 4 figures, to appear in the conference proceedings of Hot
Quarks 2012 | null | 10.1088/1742-6596/446/1/012044 | null | hep-ph nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The production and space-time evolution of heavy quarks and J/psi in the
quark gluon plasma is studied within the partonic transport model Boltzmann
Approach to MultiParton Scatterings (BAMPS). This framework allows interactions
among all partons: gluons, light quarks and heavy quarks. Heavy quarks, in
particular, interact with the rest of the medium via binary scatterings with a
running coupling and a more precise Debye screening which is derived from hard
thermal loop calculations. We compare our results of the elliptic flow and
nuclear modification factor not only to experimental data of heavy flavor
electrons at RHIC, but also to LHC data of heavy flavor electrons, muons, D
mesons, and non-prompt J/psi. Where no data is available yet, we make
predictions for those observables. Furthermore, results on prompt J/psi
elliptic flow are reported for RHIC energy within the same framework, taking
the dissociation as well as regeneration of J/psi in the quark-gluon plasma
into account.
| [
{
"created": "Mon, 3 Dec 2012 11:50:45 GMT",
"version": "v1"
}
] | 2015-06-12 | [
[
"Uphoff",
"Jan",
""
],
[
"Fochler",
"Oliver",
""
],
[
"Xu",
"Zhe",
""
],
[
"Greiner",
"Carsten",
""
]
] | The production and space-time evolution of heavy quarks and J/psi in the quark gluon plasma is studied within the partonic transport model Boltzmann Approach to MultiParton Scatterings (BAMPS). This framework allows interactions among all partons: gluons, light quarks and heavy quarks. Heavy quarks, in particular, interact with the rest of the medium via binary scatterings with a running coupling and a more precise Debye screening which is derived from hard thermal loop calculations. We compare our results of the elliptic flow and nuclear modification factor not only to experimental data of heavy flavor electrons at RHIC, but also to LHC data of heavy flavor electrons, muons, D mesons, and non-prompt J/psi. Where no data is available yet, we make predictions for those observables. Furthermore, results on prompt J/psi elliptic flow are reported for RHIC energy within the same framework, taking the dissociation as well as regeneration of J/psi in the quark-gluon plasma into account. |
hep-ph/9701203 | Salman Habib | Fred Cooper | From Landau's Hydrodynamical Model to Field Theory Models of
Multiparticle Production: A Tribute to Peter Carruthers on his 61st Birthday | 13 pages (14 figures), RevTeX (plus macro), uses epsf. CARRUTHERS61 | null | null | LA-UR-96-4514 | hep-ph | null | We review the assumptions and domain of applicability of Landau's
Hydrodynamical Model. By considering two models of particle production, pair
production from strong electric fields and particle production in the linear
sigma model, we demonstrate that many of Landau's ideas are verified in
explicit field theory calculations.
| [
{
"created": "Thu, 2 Jan 1997 18:20:39 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Cooper",
"Fred",
""
]
] | We review the assumptions and domain of applicability of Landau's Hydrodynamical Model. By considering two models of particle production, pair production from strong electric fields and particle production in the linear sigma model, we demonstrate that many of Landau's ideas are verified in explicit field theory calculations. |
hep-ph/9912367 | Yuri V. Kovchegov | Yuri V. Kovchegov (BNL), Eugene Levin (BNL/Tel Aviv University), Larry
McLerran (BNL) | Large Scale Rapidity Correlations in Heavy Ion Collisions | REVTeX, 13 pages, 3 figures | Phys.Rev. C63 (2001) 024903 | 10.1103/PhysRevC.63.024903 | BNL-NT-99/7, TAUP-2613-99 | hep-ph nucl-ex nucl-th | null | We discuss particle production mechanisms for heavy ion collisions. We
present an argument demonstrating how the fluctuations of the number of
produced particles in a series of classical emissions can account for KNO
scaling. We predict rapidity correlations in the particle production in the
event by event analysis of heavy ion collisions on the rapidity scales of the
order of one over the strong coupling constant.
| [
{
"created": "Wed, 15 Dec 1999 22:06:35 GMT",
"version": "v1"
}
] | 2009-10-31 | [
[
"Kovchegov",
"Yuri V.",
"",
"BNL"
],
[
"Levin",
"Eugene",
"",
"BNL/Tel Aviv University"
],
[
"McLerran",
"Larry",
"",
"BNL"
]
] | We discuss particle production mechanisms for heavy ion collisions. We present an argument demonstrating how the fluctuations of the number of produced particles in a series of classical emissions can account for KNO scaling. We predict rapidity correlations in the particle production in the event by event analysis of heavy ion collisions on the rapidity scales of the order of one over the strong coupling constant. |
hep-ph/0304215 | Xiao-Gang He | X.-G. He and G. Valencia | $A^b_{FB}$ and $R_b$ at LEP and New Right-Handed Gauge Bosons | Revtex 28 pages, 10 figure | Phys.Rev. D68 (2003) 033011 | 10.1103/PhysRevD.68.033011 | null | hep-ph | null | We explore models with additional right-handed gauge bosons that couple
predominantly to the third generation in the context of $b\bar{b}$ production
at LEP. In particular we investigate potential new contributions to $\delta
g_{Rb}$ that are needed if the measured $A^b_{FB}$ at the $Z$ peak is
interpreted as a signal of new physics. We identify two sources of large
$\delta g_{Rb}$ corrections: $Z-Z^\prime$ mixing at tree-level, and one-loop
effects from a new $SU_R(2)$ triplet of gauge bosons. We find that the latter
can contribute to $\delta g_{Rb}$ at the 1%-level. We place bounds on the mass
of the additional $Z^\prime$ gauge boson that occurs in these models using the
$R_b$ measurements from LEP-II. We find that even in cases where the $Z^\prime$
couples almost exclusively to the $b$ and $t$-quarks, masses lighter than about
500 GeV are already excluded.
| [
{
"created": "Wed, 23 Apr 2003 04:38:57 GMT",
"version": "v1"
}
] | 2009-11-10 | [
[
"He",
"X. -G.",
""
],
[
"Valencia",
"G.",
""
]
] | We explore models with additional right-handed gauge bosons that couple predominantly to the third generation in the context of $b\bar{b}$ production at LEP. In particular we investigate potential new contributions to $\delta g_{Rb}$ that are needed if the measured $A^b_{FB}$ at the $Z$ peak is interpreted as a signal of new physics. We identify two sources of large $\delta g_{Rb}$ corrections: $Z-Z^\prime$ mixing at tree-level, and one-loop effects from a new $SU_R(2)$ triplet of gauge bosons. We find that the latter can contribute to $\delta g_{Rb}$ at the 1%-level. We place bounds on the mass of the additional $Z^\prime$ gauge boson that occurs in these models using the $R_b$ measurements from LEP-II. We find that even in cases where the $Z^\prime$ couples almost exclusively to the $b$ and $t$-quarks, masses lighter than about 500 GeV are already excluded. |
hep-ph/0611086 | Kuang-Ta Chao | Yu-Jie Zhang, Kuang-Ta Chao | Double charm production e^+ e^- \to J/\psi + c \bar{c} at B factories
with next-to-leading order QCD corrections | a reference updated in the published version | Phys.Rev.Lett.98:092003,2007 | 10.1103/PhysRevLett.98.092003 | null | hep-ph hep-ex | null | The inclusive $J/\psi$ production in $e^+ e^- \to J/\psi c\bar c$ at B
factories is one of the most challenging open problems in heavy quarkonium
physics. The observed cross section of this double charm production process is
larger than existing leading order (LO) QCD predictions by a factor of 5. In
the nonrelativistic QCD (NRQCD) factorization formalism, we calculate the
next-to-leading order (NLO) QCD virtual and real corrections to this process,
and find that these corrections can substantially enhance the cross section
with a $K$ factor of about 1.8. We further take into account the feeddown
contributions from higher charmonium states (mainly the $\psi(2S)$ as well as
$\chi_{cJ}$) and the two-photon contributions, and find that the discrepancy
between theory and experiment can be largely removed.
| [
{
"created": "Tue, 7 Nov 2006 17:48:24 GMT",
"version": "v1"
},
{
"created": "Tue, 14 Nov 2006 16:37:29 GMT",
"version": "v2"
},
{
"created": "Thu, 1 Feb 2007 18:00:35 GMT",
"version": "v3"
},
{
"created": "Mon, 5 Mar 2007 15:53:15 GMT",
"version": "v4"
}
] | 2008-11-26 | [
[
"Zhang",
"Yu-Jie",
""
],
[
"Chao",
"Kuang-Ta",
""
]
] | The inclusive $J/\psi$ production in $e^+ e^- \to J/\psi c\bar c$ at B factories is one of the most challenging open problems in heavy quarkonium physics. The observed cross section of this double charm production process is larger than existing leading order (LO) QCD predictions by a factor of 5. In the nonrelativistic QCD (NRQCD) factorization formalism, we calculate the next-to-leading order (NLO) QCD virtual and real corrections to this process, and find that these corrections can substantially enhance the cross section with a $K$ factor of about 1.8. We further take into account the feeddown contributions from higher charmonium states (mainly the $\psi(2S)$ as well as $\chi_{cJ}$) and the two-photon contributions, and find that the discrepancy between theory and experiment can be largely removed. |
0901.0166 | David Blaschke | D. Prorok, L. Turko, D. Blaschke | Charmonium suppression at RHIC and SPS: a hadronic baseline | 16 pages, 6 figures, final version accepted for publication in Phys.
Lett. B | Phys.Lett.B690:352-357,2010 | 10.1016/j.physletb.2010.05.050 | null | hep-ph nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | A kinetic equation approach is applied to model anomalous J/psi suppression
at RHIC and SPS by absorption in a hadron resonance gas which successfully
describes statistical hadron production in both experiments. The puzzling
rapidity dependence of the PHENIX data is reproduced as a geometric effect due
to a longer absorption path for J/psi production at forward rapidity.
| [
{
"created": "Thu, 1 Jan 2009 21:17:18 GMT",
"version": "v1"
},
{
"created": "Mon, 2 Nov 2009 16:00:23 GMT",
"version": "v2"
},
{
"created": "Mon, 17 May 2010 09:54:03 GMT",
"version": "v3"
}
] | 2014-11-18 | [
[
"Prorok",
"D.",
""
],
[
"Turko",
"L.",
""
],
[
"Blaschke",
"D.",
""
]
] | A kinetic equation approach is applied to model anomalous J/psi suppression at RHIC and SPS by absorption in a hadron resonance gas which successfully describes statistical hadron production in both experiments. The puzzling rapidity dependence of the PHENIX data is reproduced as a geometric effect due to a longer absorption path for J/psi production at forward rapidity. |
hep-ph/0411375 | Hanqing Zheng | Z. X. Sun, L. Y. Xiao, Z. G. Xiao, H. Q. Zheng, Z. Y. Zhou | On the nature of the lightest scalar resonances | Talk presented by Zheng at ``Quark Confinement and Hadron
Spectroscopy VI'', 21--25 Sept. 2004, Cagliari, Italy. 3 pages with 2 figures | null | 10.1063/1.1920981 | null | hep-ph | null | We briefly review the recent progresses in the new unitarization approach
being developed by us. Especially we discuss the large $N_c$ $\pi\pi$
scatterings by making use of the partial wave $S$ matrix parametrization form.
We find that the $\sigma$ pole may move to the negative real axis on the second
sheet of the complex $s$ plane, therefore it raises the interesting question
that this `$\sigma$' pole may be related to the $\sigma$ in the linear $\sigma$
model.
| [
{
"created": "Mon, 29 Nov 2004 18:00:35 GMT",
"version": "v1"
}
] | 2009-11-10 | [
[
"Sun",
"Z. X.",
""
],
[
"Xiao",
"L. Y.",
""
],
[
"Xiao",
"Z. G.",
""
],
[
"Zheng",
"H. Q.",
""
],
[
"Zhou",
"Z. Y.",
""
]
] | We briefly review the recent progresses in the new unitarization approach being developed by us. Especially we discuss the large $N_c$ $\pi\pi$ scatterings by making use of the partial wave $S$ matrix parametrization form. We find that the $\sigma$ pole may move to the negative real axis on the second sheet of the complex $s$ plane, therefore it raises the interesting question that this `$\sigma$' pole may be related to the $\sigma$ in the linear $\sigma$ model. |
2311.09475 | Roberto Vega-Morales | Mar Bastero-Gil, Paulo B. Ferraz, Lorenzo Ubaldi, Roberto Vega-Morales | Super heavy dark matter from inflationary Schwinger production | 4 pages, 1 figure | null | null | UG-FT 328-23, CAFPE 198-23, CA21106 | hep-ph | http://creativecommons.org/licenses/by/4.0/ | We consider a simple setup with a dark sector containing dark electrons
charged under an abelian $U(1)_D$ gauge symmetry. We show that if the massless
dark photon associated to the $U(1)_D$ is produced during inflation in such a
way as to form a classical dark electric field, then dark electron-positron
pairs are also produced close to the end of inflation via the Schwinger
mechanism. Their mass is larger than the Hubble scale so they are
non-relativistic at production and remain so for the rest of their cosmic
evolution following reheating. They can account for the dark matter abundance
today in scenarios with a high scale of inflation and efficient reheating.This
points to a very heavy mass for the dark electrons of order $10^{14}$ GeV. Even
with a dark gauge coupling comparable to the visible one of electromagnetism,
the dark electrons are so heavy that they do not thermalize with the dark
photons throughout their cosmic history. Assuming negligible kinetic mixing
with the visible $U(1)$ the dark electrons remain decoupled from the Standard
Model thermal bath as well.
| [
{
"created": "Thu, 16 Nov 2023 00:37:22 GMT",
"version": "v1"
}
] | 2023-12-27 | [
[
"Bastero-Gil",
"Mar",
""
],
[
"Ferraz",
"Paulo B.",
""
],
[
"Ubaldi",
"Lorenzo",
""
],
[
"Vega-Morales",
"Roberto",
""
]
] | We consider a simple setup with a dark sector containing dark electrons charged under an abelian $U(1)_D$ gauge symmetry. We show that if the massless dark photon associated to the $U(1)_D$ is produced during inflation in such a way as to form a classical dark electric field, then dark electron-positron pairs are also produced close to the end of inflation via the Schwinger mechanism. Their mass is larger than the Hubble scale so they are non-relativistic at production and remain so for the rest of their cosmic evolution following reheating. They can account for the dark matter abundance today in scenarios with a high scale of inflation and efficient reheating.This points to a very heavy mass for the dark electrons of order $10^{14}$ GeV. Even with a dark gauge coupling comparable to the visible one of electromagnetism, the dark electrons are so heavy that they do not thermalize with the dark photons throughout their cosmic history. Assuming negligible kinetic mixing with the visible $U(1)$ the dark electrons remain decoupled from the Standard Model thermal bath as well. |
1810.06717 | Stefan Evans | Stefan Evans and Johann Rafelski | Virtual axion-like particle complement to Euler-Heisenberg-Schwinger
action | 5 pages, 2 figures | null | 10.1016/j.physletb.2019.03.008 | null | hep-ph nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We modify action in an external electromagnetic field to include effects of
virtual axion-like particle (ALP) excitations. A measurable addition to
QED-Euler-Heisenberg-Schwinger (EHS) action is obtained and incorporated into
experimental constraints placed on ALP mass and coupling to two photons. The
regime of these constraints in which the ALP vacuum effect surpasses the EHS
effect is characterized. We show that probing of the virtual vacuum effect
offers an alternative method in search for physics related to ALPs.
| [
{
"created": "Mon, 15 Oct 2018 21:55:15 GMT",
"version": "v1"
}
] | 2019-03-13 | [
[
"Evans",
"Stefan",
""
],
[
"Rafelski",
"Johann",
""
]
] | We modify action in an external electromagnetic field to include effects of virtual axion-like particle (ALP) excitations. A measurable addition to QED-Euler-Heisenberg-Schwinger (EHS) action is obtained and incorporated into experimental constraints placed on ALP mass and coupling to two photons. The regime of these constraints in which the ALP vacuum effect surpasses the EHS effect is characterized. We show that probing of the virtual vacuum effect offers an alternative method in search for physics related to ALPs. |
hep-ph/0506210 | Dennis D. Dietrich | Dennis D. Dietrich, Stefan Hofmann | Lorentz invariant ensembles of vector backgrounds | 6 pages, no figures, submitted to PLB | Phys.Lett. B632 (2006) 439-444 | 10.1016/j.physletb.2005.10.071 | null | hep-ph | null | We consider gauge field theories in the presence of ensembles of vector
backgrounds. While Lorentz invariance is explicitely broken in the presence of
any single background, here, the Lorentz invariance of the theory is restored
by averaging over a Lorentz invariant ensemble of backgrounds, i.e. a set of
background vectors that is mapped onto itself under Lorentz transformations.
This framewkork is used to study the effects of a non-trivial but Lorentz
invariant vacuum structure or mass dimension two vector condensates by
identifying the background with a shift of the gauge field. Up to now, the
ensembles used in the literature comprise configurations corresponding to
non-zero field tensors together with such with vanishing field strength. We
find that even when constraining the ensembles to pure gauge configurations,
the usual high-energy degrees of freedom are removed from the spectrum of
asymptotic states in the presence of said backgrounds in euclidean and in
Minkowski space. We establish this result not only for the propagators to all
orders in the background and otherwise at tree level but for the full
propagator.
| [
{
"created": "Wed, 22 Jun 2005 11:23:32 GMT",
"version": "v1"
}
] | 2009-11-11 | [
[
"Dietrich",
"Dennis D.",
""
],
[
"Hofmann",
"Stefan",
""
]
] | We consider gauge field theories in the presence of ensembles of vector backgrounds. While Lorentz invariance is explicitely broken in the presence of any single background, here, the Lorentz invariance of the theory is restored by averaging over a Lorentz invariant ensemble of backgrounds, i.e. a set of background vectors that is mapped onto itself under Lorentz transformations. This framewkork is used to study the effects of a non-trivial but Lorentz invariant vacuum structure or mass dimension two vector condensates by identifying the background with a shift of the gauge field. Up to now, the ensembles used in the literature comprise configurations corresponding to non-zero field tensors together with such with vanishing field strength. We find that even when constraining the ensembles to pure gauge configurations, the usual high-energy degrees of freedom are removed from the spectrum of asymptotic states in the presence of said backgrounds in euclidean and in Minkowski space. We establish this result not only for the propagators to all orders in the background and otherwise at tree level but for the full propagator. |
1212.0394 | Anirban Kundu | Indrani Chakraborty and Anirban Kundu | Controlling the fine-tuning problem with singlet scalar dark matter | 8 pages, 2 figures, added discussions on dark matter constraints and
an extra figure, conclusions unchanged, version accepted in Phys. Rev. D | null | 10.1103/PhysRevD.87.055015 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Assuming that no other conventional new physics is found immediately at the
LHC, we investigate how just the consistent solution of the scalar mass
hierarchy problem points towards the minimal necessary field content. We show
that to ameliorate the fine-tuning problem, one needs to introduce more scalar
degrees of freedom. The simplest solution is one or more real singlets (with
the possibility of combining two of them in a complex singlet), which may act
as viable cold dark matter candidates, because the constraints on the scalar
potential disfavor any mixing between the new scalar(s) with the SM doublet.
Furthermore, the fine-tuning problem of the new scalars necessitates the
introduction of vector-like fermions. Thus, singlet scalar(s) and vector
fermions are minimal enhancements over the Standard Model to alleviate the
fine-tuning problem. We also show that the model predicts Landau poles for all
the scalar couplings, whose positions depend only on the number of such
singlets. Thus, introduction of some new physics at that scale becomes
inevitable. We also discuss how the model confronts the LHC constraints and the
latest XENON100 data.
| [
{
"created": "Mon, 3 Dec 2012 14:06:15 GMT",
"version": "v1"
},
{
"created": "Tue, 5 Mar 2013 03:11:27 GMT",
"version": "v2"
}
] | 2015-06-12 | [
[
"Chakraborty",
"Indrani",
""
],
[
"Kundu",
"Anirban",
""
]
] | Assuming that no other conventional new physics is found immediately at the LHC, we investigate how just the consistent solution of the scalar mass hierarchy problem points towards the minimal necessary field content. We show that to ameliorate the fine-tuning problem, one needs to introduce more scalar degrees of freedom. The simplest solution is one or more real singlets (with the possibility of combining two of them in a complex singlet), which may act as viable cold dark matter candidates, because the constraints on the scalar potential disfavor any mixing between the new scalar(s) with the SM doublet. Furthermore, the fine-tuning problem of the new scalars necessitates the introduction of vector-like fermions. Thus, singlet scalar(s) and vector fermions are minimal enhancements over the Standard Model to alleviate the fine-tuning problem. We also show that the model predicts Landau poles for all the scalar couplings, whose positions depend only on the number of such singlets. Thus, introduction of some new physics at that scale becomes inevitable. We also discuss how the model confronts the LHC constraints and the latest XENON100 data. |
0801.1256 | Tadafumi Ohsaku | Tadafumi Ohsaku | Dynamical Dirac Mass Generation in the Supersymmetric
Nambu--Jona-Lasinio Model with the Seesaw Mechanism of Neutrinos | 8 pages, 10 figures, submitted for publication | null | null | null | hep-ph cond-mat.mes-hall cond-mat.str-el cond-mat.supr-con gr-qc hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The dynamical generation of Dirac mass in the supersymmetric
Nambu$-$Jona-Lasinio (SNJL) model with the seesaw mechanism of neutrino is
investigeted. The right and left handed Majorana mass parameters are introduced
into the SNJL model; we regard them as external model parameters. The question
on the origin of these Majorana masses are set aside, and we concentrate on the
examination of the effect of the Majorana mass parameters on the dynamical
generation of Dirac mass. The effective potential of the model and the gap
equation for the self-consistent determination of Dirac mass are derived and
solved. We use both the four-dimensional covariant and three-dimensional
non-covariant cutoff schemes for the regularizations of the effective
potential. We find there are cases of the first and second order phase
transitions with respect to variation of the coupling constant of the
Nambu$-$Jona-Lasinio-type four-body interaction of the SNJL model. In the case
of second-order phase transition, the dynamically generated Dirac mass
$|\phi_{S}|$ can arbitrarily be small compared with the right-handed Majorana
mass parameter $|M|$ and thus the seesaw condition $0<|\phi_{S}|\ll|M|$ can be
satisfied by a fine tuning of the coupling constant, while at the first-order
case it seems very difficult and/or "unnatural" to satisfy the condition. The
numerical results do not depend on the difference of the cutoff schemes
qualitatively.
| [
{
"created": "Tue, 8 Jan 2008 15:29:45 GMT",
"version": "v1"
},
{
"created": "Wed, 23 Jan 2008 22:08:41 GMT",
"version": "v2"
},
{
"created": "Sun, 27 Jan 2008 15:41:20 GMT",
"version": "v3"
},
{
"created": "Mon, 28 Apr 2008 10:34:00 GMT",
"version": "v4"
},
{
"created": "Thu, 9 Oct 2008 19:04:59 GMT",
"version": "v5"
}
] | 2016-09-08 | [
[
"Ohsaku",
"Tadafumi",
""
]
] | The dynamical generation of Dirac mass in the supersymmetric Nambu$-$Jona-Lasinio (SNJL) model with the seesaw mechanism of neutrino is investigeted. The right and left handed Majorana mass parameters are introduced into the SNJL model; we regard them as external model parameters. The question on the origin of these Majorana masses are set aside, and we concentrate on the examination of the effect of the Majorana mass parameters on the dynamical generation of Dirac mass. The effective potential of the model and the gap equation for the self-consistent determination of Dirac mass are derived and solved. We use both the four-dimensional covariant and three-dimensional non-covariant cutoff schemes for the regularizations of the effective potential. We find there are cases of the first and second order phase transitions with respect to variation of the coupling constant of the Nambu$-$Jona-Lasinio-type four-body interaction of the SNJL model. In the case of second-order phase transition, the dynamically generated Dirac mass $|\phi_{S}|$ can arbitrarily be small compared with the right-handed Majorana mass parameter $|M|$ and thus the seesaw condition $0<|\phi_{S}|\ll|M|$ can be satisfied by a fine tuning of the coupling constant, while at the first-order case it seems very difficult and/or "unnatural" to satisfy the condition. The numerical results do not depend on the difference of the cutoff schemes qualitatively. |
hep-ph/9910266 | Rajen Kundu | Rajen Kundu (Saha Institute of Nuclear Physics, Calcutta) | Selected Topics in Light Front Field Theory and Applications to the High
Energy Phenomena | PhD Thesis (using axodraw.sty in revtex) | null | null | null | hep-ph | null | In this thesis, we have presented some of the aspects of light-front (LF)
field theory through their successful application in the Deep Inelastic
Scattering (DIS). We have developed a LFQCD Hamiltonian description of the DIS
structure functions starting from Bjorken-Johnson-Low limit of virtual forward
Compton scattering amplitude and using LF current commutators. We worked in the
LF gauge $A^+=0$ and used the old-fashioned LFQCD perturbation theory in our
calculations. The importance of our work are summarized below.
Our approach shares the intution of parton model and addresses directly the
structure functions, which are experimental objects, instead of its moments as
in OPE method. Moreover, it can potentially incorporate the non-perturbative
contents of the structure functions as we have demonstrated by introducing a
new factorization scheme.
In the context of nucleonic helicity structure, the well known gauge fixed LF
helicity operator is shown to provide consistent physical information and helps
us defining new relevant structure functions. The anomalous dimensions relevant
for the $Q^2$-evolution of such structure functions are calculated.
Our study is important in establishing the equivalance of LF field theory and
the usual equal-time one through perturbative calculations of the dressed
parton structure functions reproducing the well known results. Also the
importance of Gallilean boost symmetry in understanding the correctness of any
higher order calculation using ($x^+$)-ordered LFQCD perturbation theory are
emphasized.
| [
{
"created": "Thu, 7 Oct 1999 12:31:46 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Kundu",
"Rajen",
"",
"Saha Institute of Nuclear Physics, Calcutta"
]
] | In this thesis, we have presented some of the aspects of light-front (LF) field theory through their successful application in the Deep Inelastic Scattering (DIS). We have developed a LFQCD Hamiltonian description of the DIS structure functions starting from Bjorken-Johnson-Low limit of virtual forward Compton scattering amplitude and using LF current commutators. We worked in the LF gauge $A^+=0$ and used the old-fashioned LFQCD perturbation theory in our calculations. The importance of our work are summarized below. Our approach shares the intution of parton model and addresses directly the structure functions, which are experimental objects, instead of its moments as in OPE method. Moreover, it can potentially incorporate the non-perturbative contents of the structure functions as we have demonstrated by introducing a new factorization scheme. In the context of nucleonic helicity structure, the well known gauge fixed LF helicity operator is shown to provide consistent physical information and helps us defining new relevant structure functions. The anomalous dimensions relevant for the $Q^2$-evolution of such structure functions are calculated. Our study is important in establishing the equivalance of LF field theory and the usual equal-time one through perturbative calculations of the dressed parton structure functions reproducing the well known results. Also the importance of Gallilean boost symmetry in understanding the correctness of any higher order calculation using ($x^+$)-ordered LFQCD perturbation theory are emphasized. |
hep-ph/0611150 | Daniel Zwanziger | Daniel Zwanziger | On the Equation of State of the Gluon Plasma | 8 pages, Talk given at Quark Confinement and Hadron Spectrum VII, 2-7
September, 2006, Ponta Delgada, Azores, Portugal | AIPConf.Proc.892:121-127,2007 | 10.1063/1.2714355 | null | hep-ph | null | We consider a local, renormalizable, BRST-invariant action for QCD in Coulomb
gauge that contains auxiliary bose and fermi ghost fields. It possess a
non-perturbative vacuum that spontaneously breaks BRST-invariance. The vacuum
condition leads to a gap equation that introduces a mass scale. Calculations
are done to one-loop order in a perturbative expansion about this vacuum. They
are free of the finite-$T$ infrared divergences found by Lind\'{e} and which
occur in the order $g^6$ corrections to the Stefan-Boltzmann equation of state.
We obtain a finite result for these corrections.
| [
{
"created": "Fri, 10 Nov 2006 16:58:51 GMT",
"version": "v1"
}
] | 2008-11-26 | [
[
"Zwanziger",
"Daniel",
""
]
] | We consider a local, renormalizable, BRST-invariant action for QCD in Coulomb gauge that contains auxiliary bose and fermi ghost fields. It possess a non-perturbative vacuum that spontaneously breaks BRST-invariance. The vacuum condition leads to a gap equation that introduces a mass scale. Calculations are done to one-loop order in a perturbative expansion about this vacuum. They are free of the finite-$T$ infrared divergences found by Lind\'{e} and which occur in the order $g^6$ corrections to the Stefan-Boltzmann equation of state. We obtain a finite result for these corrections. |
hep-ph/9211203 | null | Herbert Dreiner | Bell's Inequality and $\tau$-Physics at LEP | 7 pages, no figures, Oxford Preprint OUTP-92-27P | null | null | null | hep-ph | null | In this talk given at the TAU92 Workshop, Columbus, OH, Sept. 92, we
summarize results presented in more detail in a recent paper by S. Abel, M.
Dittmar and the author where we gave a general proof that Bell's inequality can
not be tested at a collider experiment. In particular, a measurement of
correlated tau-spins at LEP does not constitute a test of local realistic
theories via Bell's inequality. The central point of the argument is that such
tests, where the spins of two particles are inferred from a scattering
distribution, can always be described by a local hidden variable theory. In
response to questions at the workshop we go beyond the paper and show that an
old experiment involving the measurement of the correlated spins of the two
photons emitted in positronium decay via Compton-scattering is also not a
viable test of Bell's inequality.
| [
{
"created": "Mon, 2 Nov 1992 17:43:00 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Dreiner",
"Herbert",
""
]
] | In this talk given at the TAU92 Workshop, Columbus, OH, Sept. 92, we summarize results presented in more detail in a recent paper by S. Abel, M. Dittmar and the author where we gave a general proof that Bell's inequality can not be tested at a collider experiment. In particular, a measurement of correlated tau-spins at LEP does not constitute a test of local realistic theories via Bell's inequality. The central point of the argument is that such tests, where the spins of two particles are inferred from a scattering distribution, can always be described by a local hidden variable theory. In response to questions at the workshop we go beyond the paper and show that an old experiment involving the measurement of the correlated spins of the two photons emitted in positronium decay via Compton-scattering is also not a viable test of Bell's inequality. |
2210.04917 | Duncan Adams | Duncan Adams, Daniel Baxter, Hannah Day, Rouven Essig, Yonatan Kahn | Measuring the Migdal effect in semiconductors for dark matter detection | 17 pages, 5 figures | Phys. Rev. D 107, L041303 (2023) | 10.1103/PhysRevD.107.L041303 | FERMILAB-PUB-22-705-PPD-QIS-T | hep-ph astro-ph.IM hep-ex physics.ins-det | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The Migdal effect has received much attention from the dark matter direct
detection community, in particular due to its power in setting limits on
sub-GeV particle dark matter. Currently, there is no experimental confirmation
of the Migdal effect through nuclear scattering using Standard Model probes. In
this work, we extend existing calculations of the Migdal effect to the case of
neutron-nucleus scattering, with a particular focus on neutron scattering angle
distributions in silicon. We identify kinematic regimes wherein the assumptions
present in current calculations of the Migdal effect hold for neutron
scattering, and demonstrate that these include viable neutron calibration
schemes. We then apply this framework to propose an experimental strategy to
measure the Migdal effect in cryogenic silicon detectors using an upgrade to
the NEXUS facility at Fermilab.
| [
{
"created": "Mon, 10 Oct 2022 18:00:03 GMT",
"version": "v1"
},
{
"created": "Wed, 22 Mar 2023 21:09:03 GMT",
"version": "v2"
}
] | 2023-03-24 | [
[
"Adams",
"Duncan",
""
],
[
"Baxter",
"Daniel",
""
],
[
"Day",
"Hannah",
""
],
[
"Essig",
"Rouven",
""
],
[
"Kahn",
"Yonatan",
""
]
] | The Migdal effect has received much attention from the dark matter direct detection community, in particular due to its power in setting limits on sub-GeV particle dark matter. Currently, there is no experimental confirmation of the Migdal effect through nuclear scattering using Standard Model probes. In this work, we extend existing calculations of the Migdal effect to the case of neutron-nucleus scattering, with a particular focus on neutron scattering angle distributions in silicon. We identify kinematic regimes wherein the assumptions present in current calculations of the Migdal effect hold for neutron scattering, and demonstrate that these include viable neutron calibration schemes. We then apply this framework to propose an experimental strategy to measure the Migdal effect in cryogenic silicon detectors using an upgrade to the NEXUS facility at Fermilab. |
hep-ph/0005012 | Adam Para | Adam Para | Neutrino Oscillations Experiments at Fermilab | null | Acta Phys.Polon.B31:1313-1328,2000 | null | null | hep-ph | null | Neutrino oscillations provide an unique opportunity to probe physics beyond
the Standard Model. Fermilab is constructing two new neutrino beams to provide
a decicive test of two of the recent positive indications for neutrino
oscillations: MiniBOONE experiment will settle the LSND controversy, MINOS will
provide detailed studies of the region indicated by the SuperK results.
| [
{
"created": "Mon, 1 May 2000 18:25:48 GMT",
"version": "v1"
}
] | 2011-04-20 | [
[
"Para",
"Adam",
""
]
] | Neutrino oscillations provide an unique opportunity to probe physics beyond the Standard Model. Fermilab is constructing two new neutrino beams to provide a decicive test of two of the recent positive indications for neutrino oscillations: MiniBOONE experiment will settle the LSND controversy, MINOS will provide detailed studies of the region indicated by the SuperK results. |
hep-ph/0511154 | Wim de Boer | W. de Boer (1), C. Sander (1), V. Zhukov (1), A.V. Gladyshev (2), D.I.
Kazakov (2) ((1) Univ. Karlsruhe (2) JINR (Dubna)) | The supersymmetric interpretation of the EGRET excess of diffuse
Galactic gamma rays | 11 pages, 6 figures, extended version with more figures, as accepted
for publication in Phys. Letters B | Phys.Lett.B636:13-19,2006 | 10.1016/j.physletb.2006.03.028 | null | hep-ph astro-ph | null | Recently it was shown that the excess of diffuse Galactic gamma rays above 1
GeV traces the Dark Matter halo, as proven by reconstructing the peculiar shape
of the rotation curve of our Galaxy from the gamma ray excess. This can be
interpreted as a Dark Matter annihilation signal. In this paper we investigate
if this interpretation is consistent with Supersymmetry. It is found that the
EGRET excess combined with all electroweak constraints is fully consistent with
the minimal mSUGRA model for scalars in the TeV range and gauginos below 500
GeV.
| [
{
"created": "Sat, 12 Nov 2005 16:22:47 GMT",
"version": "v1"
},
{
"created": "Sat, 11 Mar 2006 13:21:57 GMT",
"version": "v2"
}
] | 2008-11-26 | [
[
"de Boer",
"W.",
"",
"Univ. Karlsruhe"
],
[
"Sander",
"C.",
"",
"Univ. Karlsruhe"
],
[
"Zhukov",
"V.",
"",
"Univ. Karlsruhe"
],
[
"Gladyshev",
"A. V.",
"",
"JINR"
],
[
"Kazakov",
"D. I.",
"",
"JINR"
]
] | Recently it was shown that the excess of diffuse Galactic gamma rays above 1 GeV traces the Dark Matter halo, as proven by reconstructing the peculiar shape of the rotation curve of our Galaxy from the gamma ray excess. This can be interpreted as a Dark Matter annihilation signal. In this paper we investigate if this interpretation is consistent with Supersymmetry. It is found that the EGRET excess combined with all electroweak constraints is fully consistent with the minimal mSUGRA model for scalars in the TeV range and gauginos below 500 GeV. |
hep-ph/0203135 | Mikolaj Misiak | Andrzej J. Buras, Andrzej Czarnecki, Mikolaj Misiak and Joerg Urban | Completing the NLO QCD calculation of B -> Xs gamma | 18 pages, 2 figures, uses graphicx | Nucl.Phys. B631 (2002) 219-238 | 10.1016/S0550-3213(02)00261-4 | TUM-HEP-455/02, Alberta Thy 05-02, IFT-5/2002 | hep-ph | null | We evaluate two-loop b -> s gamma matrix elements of all the four-quark
operators containing no derivatives. Contrary to previous calculations, no
expansion in the mass ratio mc/mb is performed, and all the possible Dirac and
flavor structures are included. Consequently, we are able to provide the last
item in the NLO analysis of B -> Xs gamma that has been missing so far, namely
the two-loop matrix elements of the QCD-penguin operators. Due to smallness of
the Wilson coefficients of those operators in the Standard Model, their effect
on the branching ratio is small: a reduction by roughly 1%. We find BR[ B -> Xs
gamma]_{E_gamma > 1.6 GeV} = (3.57 +_ 0.30)*10^{-4}.
| [
{
"created": "Thu, 14 Mar 2002 20:34:39 GMT",
"version": "v1"
}
] | 2009-11-07 | [
[
"Buras",
"Andrzej J.",
""
],
[
"Czarnecki",
"Andrzej",
""
],
[
"Misiak",
"Mikolaj",
""
],
[
"Urban",
"Joerg",
""
]
] | We evaluate two-loop b -> s gamma matrix elements of all the four-quark operators containing no derivatives. Contrary to previous calculations, no expansion in the mass ratio mc/mb is performed, and all the possible Dirac and flavor structures are included. Consequently, we are able to provide the last item in the NLO analysis of B -> Xs gamma that has been missing so far, namely the two-loop matrix elements of the QCD-penguin operators. Due to smallness of the Wilson coefficients of those operators in the Standard Model, their effect on the branching ratio is small: a reduction by roughly 1%. We find BR[ B -> Xs gamma]_{E_gamma > 1.6 GeV} = (3.57 +_ 0.30)*10^{-4}. |
1807.09736 | Claudia Garcia-Garcia | E. Arganda, C. Garcia-Garcia, M. J. Herrero | Probing the Higgs self-coupling through double Higgs production in
vector boson scattering at the LHC | 18 figures (34 plots), 7 tables, 30 pages. Definitive version
published in Nuclear Physics B 945 (2019) 114687 with enlarged discussion
section | Nuclear Physics B 945 (2019) 114687 | 10.1016/j.nuclphysb.2019.114687 | IFT-UAM/CSIC-18-66, FTUAM-18-17 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this work we explore the sensitivity to the Higgs self-coupling $\lambda$
in the production of two Higgs bosons via vector boson scattering at the LHC.
Although these production channels, concretely $W^+W^- \to HH$ and $ ZZ \to
HH$, have lower rates than gluon-gluon fusion, they benefit from being tree
level processes, being independent of top physics and having very distinctive
kinematics that allow to obtain very clean experimental signatures. This makes
them competitive channels concerning the sensitivity to the Higgs
self-coupling. In order to give predictions for the sensitivity to this
coupling, we first study the role of $\lambda$ at the subprocess level, both in
and beyond the Standard Model, to move afterwards to the LHC scenario. We
characterize the $pp\to HHjj$ case first and then provide quantitative results
for the values of $\lambda$ that can be probed at the LHC in vector boson
scattering processes after considering the Higgs boson decays. We focus mainly
in $pp\to b\bar{b}b\bar{b}jj$, since it has the largest signal rates, and also
comment on the potential of other channels, such as $pp\to b\bar{b}\gamma\gamma
jj$, as they lead to cleaner, although smaller, signals. Our whole study is
performed for a center of mass energy of $\sqrt{s}=14$ TeV and for various
future expected LHC luminosities.
| [
{
"created": "Wed, 25 Jul 2018 17:30:15 GMT",
"version": "v1"
},
{
"created": "Thu, 15 Nov 2018 18:46:22 GMT",
"version": "v2"
},
{
"created": "Mon, 15 Jul 2019 15:08:27 GMT",
"version": "v3"
}
] | 2019-07-16 | [
[
"Arganda",
"E.",
""
],
[
"Garcia-Garcia",
"C.",
""
],
[
"Herrero",
"M. J.",
""
]
] | In this work we explore the sensitivity to the Higgs self-coupling $\lambda$ in the production of two Higgs bosons via vector boson scattering at the LHC. Although these production channels, concretely $W^+W^- \to HH$ and $ ZZ \to HH$, have lower rates than gluon-gluon fusion, they benefit from being tree level processes, being independent of top physics and having very distinctive kinematics that allow to obtain very clean experimental signatures. This makes them competitive channels concerning the sensitivity to the Higgs self-coupling. In order to give predictions for the sensitivity to this coupling, we first study the role of $\lambda$ at the subprocess level, both in and beyond the Standard Model, to move afterwards to the LHC scenario. We characterize the $pp\to HHjj$ case first and then provide quantitative results for the values of $\lambda$ that can be probed at the LHC in vector boson scattering processes after considering the Higgs boson decays. We focus mainly in $pp\to b\bar{b}b\bar{b}jj$, since it has the largest signal rates, and also comment on the potential of other channels, such as $pp\to b\bar{b}\gamma\gamma jj$, as they lead to cleaner, although smaller, signals. Our whole study is performed for a center of mass energy of $\sqrt{s}=14$ TeV and for various future expected LHC luminosities. |
hep-ph/9501226 | Kim Yeong Gyun | Yeong Gyun Kim, Jae Yong Lee, Kang Young Lee and Jae Kwan Kim | $B \rightarrow {\tau}{\nu}X$ decays in a two Higgs doublet model | 15 pages, revtex, 1 postscript figure is attached. | null | null | KAIST--CHEP--94/13 | hep-ph | null | We calculate the decay rate for inclusive $B \rightarrow {\tau}{\nu}X$ decays
in a two Higgs doublet model using heavy quark expansion and operator product
expansion. Combined with the recent measurement of Br($B \ra \tau \nu X$), we
find a limit $\tan \beta < 0.58 m_H/\mbox{GeV}$ at 90\%\ C.L..
| [
{
"created": "Fri, 6 Jan 1995 19:36:59 GMT",
"version": "v1"
},
{
"created": "Mon, 9 Jan 1995 18:18:32 GMT",
"version": "v2"
}
] | 2016-09-01 | [
[
"Kim",
"Yeong Gyun",
""
],
[
"Lee",
"Jae Yong",
""
],
[
"Lee",
"Kang Young",
""
],
[
"Kim",
"Jae Kwan",
""
]
] | We calculate the decay rate for inclusive $B \rightarrow {\tau}{\nu}X$ decays in a two Higgs doublet model using heavy quark expansion and operator product expansion. Combined with the recent measurement of Br($B \ra \tau \nu X$), we find a limit $\tan \beta < 0.58 m_H/\mbox{GeV}$ at 90\%\ C.L.. |
1008.1621 | Kang Zhao-Feng | Zhaofeng Kang, Tianjun Li | Decaying Dark Matter in the Supersymmetric Standard Model with Freeze-in
and Seesaw mechanims | 24 pages,3 figures | JHEP 1102:035,2011 | 10.1007/JHEP02(2011)035 | null | hep-ph astro-ph.CO | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Inspired by the decaying dark matter (DM) which can explain cosmic ray
anomalies naturally, we consider the supersymmetric Standard Model with three
right-handed neutrinos (RHNs) and R-parity, and introduce a TeV-scale DM sector
with two fields \phi_{1,2} and a $Z_3$ discrete symmetry. The DM sector only
interacts with the RHNs via a very heavy field exchange and then we can explain
the cosmic ray anomalies. With the second right-handed neutrino N_2 dominant
seesaw mechanism at the low scale around 10^4 GeV, we show that \phi_{1,2} can
obtain the vacuum expectation values around the TeV scale, and then the
lightest state from \phi_{1,2} is the decay DM with lifetime around \sim
10^{26}s. In particular, the DM very long lifetime is related to the tiny
neutrino masses, and the dominant DM decay channels to \mu and \tau are related
to the approximate \mu-\tau symmetry. Furthermore, the correct DM relic density
can be obtained via the freeze-in mechanism, the small-scale problem for power
spectrum can be solved due to the decays of the R-parity odd meta-stable states
in the DM sector, and the baryon asymmetry can be generated via the soft
leptogensis.
| [
{
"created": "Tue, 10 Aug 2010 02:41:41 GMT",
"version": "v1"
}
] | 2011-02-15 | [
[
"Kang",
"Zhaofeng",
""
],
[
"Li",
"Tianjun",
""
]
] | Inspired by the decaying dark matter (DM) which can explain cosmic ray anomalies naturally, we consider the supersymmetric Standard Model with three right-handed neutrinos (RHNs) and R-parity, and introduce a TeV-scale DM sector with two fields \phi_{1,2} and a $Z_3$ discrete symmetry. The DM sector only interacts with the RHNs via a very heavy field exchange and then we can explain the cosmic ray anomalies. With the second right-handed neutrino N_2 dominant seesaw mechanism at the low scale around 10^4 GeV, we show that \phi_{1,2} can obtain the vacuum expectation values around the TeV scale, and then the lightest state from \phi_{1,2} is the decay DM with lifetime around \sim 10^{26}s. In particular, the DM very long lifetime is related to the tiny neutrino masses, and the dominant DM decay channels to \mu and \tau are related to the approximate \mu-\tau symmetry. Furthermore, the correct DM relic density can be obtained via the freeze-in mechanism, the small-scale problem for power spectrum can be solved due to the decays of the R-parity odd meta-stable states in the DM sector, and the baryon asymmetry can be generated via the soft leptogensis. |
2211.12516 | Martin Hoferichter | Andreas Crivellin, Martin Hoferichter | Width effects of broad new resonances in loop observables and
application to $(g-2)_\mu$ | 13 pages, 4 figures; journal version | Phys. Rev. D 108, 013005 (2023) | 10.1103/PhysRevD.108.013005 | PSI-PR-22-33, ZU-TH 55/22 | hep-ph hep-ex hep-lat nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In the phenomenology of strong interactions most physical states acquire a
substantial width, and thus can only be defined in a model-independent way by
pole positions and residues of the $S$-matrix. This information is incorporated
in the K\"all\'en-Lehmann representation, whose spectral function characterizes
the shape of the resonance and can be constrained by the dominant decay
channels. Here, we argue that similar effects become important whenever
beyond-the-Standard-Model particles possess a sizable decay width - as possible
for instance in cases with a large branching fraction to a dark sector or
strongly coupled scenarios - and show how their widths can be incorporated in
the calculation of loop observables. As an application, we consider the
anomalous magnetic moment of the muon, including both the direct effect of new
physics and the possible indirect impact of a broad light $Z'$ on
$e^+e^-\to\text{hadrons}$ cross sections. Throughout, we provide results for a
general spectral function and its reconstruction from the one-loop imaginary
part, where the latter captures the leading two-loop effects.
| [
{
"created": "Tue, 22 Nov 2022 19:00:00 GMT",
"version": "v1"
},
{
"created": "Mon, 17 Jul 2023 14:55:14 GMT",
"version": "v2"
}
] | 2023-07-18 | [
[
"Crivellin",
"Andreas",
""
],
[
"Hoferichter",
"Martin",
""
]
] | In the phenomenology of strong interactions most physical states acquire a substantial width, and thus can only be defined in a model-independent way by pole positions and residues of the $S$-matrix. This information is incorporated in the K\"all\'en-Lehmann representation, whose spectral function characterizes the shape of the resonance and can be constrained by the dominant decay channels. Here, we argue that similar effects become important whenever beyond-the-Standard-Model particles possess a sizable decay width - as possible for instance in cases with a large branching fraction to a dark sector or strongly coupled scenarios - and show how their widths can be incorporated in the calculation of loop observables. As an application, we consider the anomalous magnetic moment of the muon, including both the direct effect of new physics and the possible indirect impact of a broad light $Z'$ on $e^+e^-\to\text{hadrons}$ cross sections. Throughout, we provide results for a general spectral function and its reconstruction from the one-loop imaginary part, where the latter captures the leading two-loop effects. |
hep-ph/9802302 | null | G. Montagna, O. Nicrosini and F. Piccinini | Precision Physics at LEP | Review paper to appear in the RIVISTA DEL NUOVO CIMENTO; 160 pages,
LateX, 70 eps figures included | Riv.Nuovo Cim. 21N9 (1998) 1-162 | 10.1007/BF02845546 | FNT/T 97/19 | hep-ph hep-ex nucl-ex nucl-th | null | 1 - Introduction
2 - Small-Angle Bhabha Scattering and the Luminosity Measurement
3 - Z^0 Physics
4 - Fits to Precision Data
5 - Physics at LEP2
6 - Conclusions
| [
{
"created": "Wed, 11 Feb 1998 18:38:02 GMT",
"version": "v1"
}
] | 2015-06-25 | [
[
"Montagna",
"G.",
""
],
[
"Nicrosini",
"O.",
""
],
[
"Piccinini",
"F.",
""
]
] | 1 - Introduction 2 - Small-Angle Bhabha Scattering and the Luminosity Measurement 3 - Z^0 Physics 4 - Fits to Precision Data 5 - Physics at LEP2 6 - Conclusions |
1212.5903 | Zhenjun Xiao | Wen-Fei Wang, Ying-Ying Fan and Zhen-Jun Xiao | Semileptonic decays $B_c\to(\eta_c,J/\Psi)l\nu$ in the perturbative QCD
approach | 12 pages, 2 figures, typos removed, some modifications in content and
the numerical results. To be published in Chinese Physics C | null | 10.1088/1674-1137/37/9/093102 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this paper we study the semileptonic decays of $B_c^- \to
(\eta_c,J/\psi)l^-\bar\nu_l$. We firstly evaluate the $B_c \to (\eta_c,J/\Psi)$
transition form factors $F_0(q^2)$, $F_+(q^2)$, $V(q^2)$ and $A_{0,1,2}(q^2)$
by employing the pQCD factorization approach, and then we calculate the
branching ratios for all considered semileptonic decays. Based on the numerical
results and the phenomenological analysis, we find that: (a) the pQCD
predictions for the values of the $B_c \to \eta_c$ and $B_c \to J/\Psi$
transition form factors agree well with those obtained by using other methods;
(b) the pQCD predictions for the branching ratios of the considered decays are
$Br\left(B_c^- \to\eta_c e^-\bar\nu_e(\mu^-\bar\nu_\mu)\right)
=(4.41^{+1.22}_{-1.09})\times10^{-3}$, $Br\left(B_c^-
\to\eta_c\tau^-\bar\nu_\tau\right) =(1.37^{+0.37}_{-0.34})\times10^{-3}$,
$Br(B_c^- \to J/\Psi e^-\bar\nu_e(\mu^-\bar\nu_\mu))
=(10.03^{+1.33}_{-1.18})\times10^{-3}$, and $Br\left(B_c^- \to
J/\Psi\tau^-\bar\nu_\tau\right) =(2.92^{+0.40}_{-0.34})\times10^{-3}$; and (c)
we also define and calculate two ratios of the branching ratios $R_{\eta_c}$
and $R_{J/\Psi}$, which will be tested by LHCb and the forthcoming Super-B
experiments.
| [
{
"created": "Mon, 24 Dec 2012 12:24:30 GMT",
"version": "v1"
},
{
"created": "Wed, 30 Jan 2013 14:41:50 GMT",
"version": "v2"
}
] | 2015-06-12 | [
[
"Wang",
"Wen-Fei",
""
],
[
"Fan",
"Ying-Ying",
""
],
[
"Xiao",
"Zhen-Jun",
""
]
] | In this paper we study the semileptonic decays of $B_c^- \to (\eta_c,J/\psi)l^-\bar\nu_l$. We firstly evaluate the $B_c \to (\eta_c,J/\Psi)$ transition form factors $F_0(q^2)$, $F_+(q^2)$, $V(q^2)$ and $A_{0,1,2}(q^2)$ by employing the pQCD factorization approach, and then we calculate the branching ratios for all considered semileptonic decays. Based on the numerical results and the phenomenological analysis, we find that: (a) the pQCD predictions for the values of the $B_c \to \eta_c$ and $B_c \to J/\Psi$ transition form factors agree well with those obtained by using other methods; (b) the pQCD predictions for the branching ratios of the considered decays are $Br\left(B_c^- \to\eta_c e^-\bar\nu_e(\mu^-\bar\nu_\mu)\right) =(4.41^{+1.22}_{-1.09})\times10^{-3}$, $Br\left(B_c^- \to\eta_c\tau^-\bar\nu_\tau\right) =(1.37^{+0.37}_{-0.34})\times10^{-3}$, $Br(B_c^- \to J/\Psi e^-\bar\nu_e(\mu^-\bar\nu_\mu)) =(10.03^{+1.33}_{-1.18})\times10^{-3}$, and $Br\left(B_c^- \to J/\Psi\tau^-\bar\nu_\tau\right) =(2.92^{+0.40}_{-0.34})\times10^{-3}$; and (c) we also define and calculate two ratios of the branching ratios $R_{\eta_c}$ and $R_{J/\Psi}$, which will be tested by LHCb and the forthcoming Super-B experiments. |
1507.04962 | Jonathan Davis | Jonathan H. Davis, Joseph Silk, Celine Boehm, Kumiko Kotera, Colin
Norman | Shocking Signals of Dark Matter Annihilation | 9 pages, 4 figures | Phys. Rev. D 93, 103523 (2016) | 10.1103/PhysRevD.93.103523 | null | hep-ph astro-ph.HE | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We examine whether charged particles injected by self-annihilating Dark
Matter into regions undergoing Diffuse Shock Acceleration (DSA) can be
accelerated to high energies. We consider three astrophysical sites where shock
acceleration is supposed to occur, namely the Galactic Centre, galaxy clusters
and Active Galactic Nuclei (AGN). For the Milky Way, we find that the
acceleration of cosmic rays injected by dark matter could lead to a bump in the
cosmic ray spectrum provided that the product of the efficiency of the
acceleration mechanism and the concentration of DM particles is high enough.
Among the various acceleration sources that we consider (namely supernova
remnants (SNRs), Fermi bubbles and AGN jets), we find that the Fermi bubbles
are a potentially more efficient accelerator than SNRs. However both could in
principle accelerate electrons and protons injected by dark matter to very high
energies. At the extragalactic level, the acceleration of dark matter
annihilation products could be responsible for enhanced radio emission from
colliding clusters and prediction of an increase of the anti-deuteron flux
generated near AGNs.
| [
{
"created": "Fri, 17 Jul 2015 13:16:30 GMT",
"version": "v1"
}
] | 2016-05-26 | [
[
"Davis",
"Jonathan H.",
""
],
[
"Silk",
"Joseph",
""
],
[
"Boehm",
"Celine",
""
],
[
"Kotera",
"Kumiko",
""
],
[
"Norman",
"Colin",
""
]
] | We examine whether charged particles injected by self-annihilating Dark Matter into regions undergoing Diffuse Shock Acceleration (DSA) can be accelerated to high energies. We consider three astrophysical sites where shock acceleration is supposed to occur, namely the Galactic Centre, galaxy clusters and Active Galactic Nuclei (AGN). For the Milky Way, we find that the acceleration of cosmic rays injected by dark matter could lead to a bump in the cosmic ray spectrum provided that the product of the efficiency of the acceleration mechanism and the concentration of DM particles is high enough. Among the various acceleration sources that we consider (namely supernova remnants (SNRs), Fermi bubbles and AGN jets), we find that the Fermi bubbles are a potentially more efficient accelerator than SNRs. However both could in principle accelerate electrons and protons injected by dark matter to very high energies. At the extragalactic level, the acceleration of dark matter annihilation products could be responsible for enhanced radio emission from colliding clusters and prediction of an increase of the anti-deuteron flux generated near AGNs. |
1009.2400 | Jeronimo Peralta Ramos | E. Calzetta and J. Peralta-Ramos | Linking the hydrodynamic and kinetic description of a dissipative
relativistic conformal theory | v2: 23 pages, no figures, accepted in Phys. Rev. D | Phys.Rev.D82:106003,2010 | 10.1103/PhysRevD.82.106003 | null | hep-ph nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We use the entropy production variational method to associate a one particle
distribution function to the assumed known energy-momentum and entropy currents
describing a relativistic conformal fluid. Assuming a simple form for the
collision operator we find this one particle distribution function explicitly,
and show that this method of linking the hydro and kinetic description is a non
trivial generalization of Grad's ansatz. The resulting constitutive relations
are the same as in the conformal dissipative type theories discussed in J.
Peralta-Ramos and E. Calzetta, Phys. Rev. D {\bfseries 80}, 126002 (2009). Our
results may prove useful in the description of freeze-out in ultrarelativistic
heavy-ion collisions.
| [
{
"created": "Mon, 13 Sep 2010 14:06:57 GMT",
"version": "v1"
},
{
"created": "Tue, 19 Oct 2010 22:25:20 GMT",
"version": "v2"
}
] | 2011-05-18 | [
[
"Calzetta",
"E.",
""
],
[
"Peralta-Ramos",
"J.",
""
]
] | We use the entropy production variational method to associate a one particle distribution function to the assumed known energy-momentum and entropy currents describing a relativistic conformal fluid. Assuming a simple form for the collision operator we find this one particle distribution function explicitly, and show that this method of linking the hydro and kinetic description is a non trivial generalization of Grad's ansatz. The resulting constitutive relations are the same as in the conformal dissipative type theories discussed in J. Peralta-Ramos and E. Calzetta, Phys. Rev. D {\bfseries 80}, 126002 (2009). Our results may prove useful in the description of freeze-out in ultrarelativistic heavy-ion collisions. |
hep-ph/0601270 | Nikolaos Stefanis | N. G. Stefanis, A. P. Bakulev, A. I. Karanikas, S. V. Mikhailov | Fractional Analytic Perturbation Theory in QCD and Exclusive Reactions | 7 pages, 1 figure, 1 table, needs hsqcd.cls. Invited plenary talk
presented by the first author at Hadron Structure and QCD: from Low to High
Energies, St. Petersburg, Russia, 20-24 September 2005 | null | null | RUB-TPII-01/06 | hep-ph | null | Different ``analytization'' procedures for the factorized pion form factor
are discussed in comparison with the standard QCD perturbation theory at NLO.
It is argued that demanding the analyticity of the exclusive amplitude as a
\emph{whole}, entails insensitivity of the results on all scheme and
scale-setting parameters, including the factorization scale. This enables us to
develop an approach of optimized perturbation theory within the MS-bar scheme
and to generalize the Analytic Perturbation Theory to non-integer (fractional)
powers of the strong running coupling in the complex Q^2 plane
| [
{
"created": "Tue, 31 Jan 2006 17:14:14 GMT",
"version": "v1"
},
{
"created": "Wed, 1 Feb 2006 14:01:21 GMT",
"version": "v2"
}
] | 2007-05-23 | [
[
"Stefanis",
"N. G.",
""
],
[
"Bakulev",
"A. P.",
""
],
[
"Karanikas",
"A. I.",
""
],
[
"Mikhailov",
"S. V.",
""
]
] | Different ``analytization'' procedures for the factorized pion form factor are discussed in comparison with the standard QCD perturbation theory at NLO. It is argued that demanding the analyticity of the exclusive amplitude as a \emph{whole}, entails insensitivity of the results on all scheme and scale-setting parameters, including the factorization scale. This enables us to develop an approach of optimized perturbation theory within the MS-bar scheme and to generalize the Analytic Perturbation Theory to non-integer (fractional) powers of the strong running coupling in the complex Q^2 plane |
0803.1160 | Ulrich Baur | U. Baur (Buffalo) and L.H. Orr (Rochester) | Searching for t-bar t Resonances at the Large Hadron Collider | revtex3, 27 pages, 5 tables, 6 figures | Phys.Rev.D77:114001,2008 | 10.1103/PhysRevD.77.114001 | UB-HET-08-01 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Many new physics models predict resonances with masses in the TeV range which
decay into a pair of top quarks. With its large cross section, t-bar t
production at the Large Hadron Collider (LHC) offers an excellent opportunity
to search for such particles. We present a detailed study of the discovery
potential of the CERN Large Hadron Collider for Kaluza-Klein (KK) excitations
of the gluon in bulk Randall-Sundrum (RS) models in the t-bar t -> ell^+/- nu
b-bar bq-bar q' (ell=e, mu) final state. We utilize final states with one or
two tagged b-quarks, and two, three or four jets (including b-jets). Our
calculations take into account the finite resolution of detectors, the energy
loss due to b-quark decays, the expected reduced b-tagging efficiency at large
t-bar t invariant masses, and include the background originating from Wb-bar
b+jets, (Wb+W-bar b)+jets, W+jets, and single top + jets production. We derive
semi-realistic 5 sigma discovery limits for nine different KK gluon scenarios,
and compare them with those for KK gravitons, and a Z_H boson in the Littlest
Higgs model. We also analyze the capabilities of the LHC experiments to
differentiate between individual KK gluon models and measure the couplings of
KK gluons to quarks. We find that, for the parameters and models chosen, KK
gluons with masses up to about 4 TeV can be discovered at the LHC. The ability
of the LHC to discriminate between different bulk RS models, and to measure the
couplings of the KK gluons is found to be highly model dependent.
| [
{
"created": "Fri, 7 Mar 2008 19:43:44 GMT",
"version": "v1"
}
] | 2008-11-26 | [
[
"Baur",
"U.",
"",
"Buffalo"
],
[
"Orr",
"L. H.",
"",
"Rochester"
]
] | Many new physics models predict resonances with masses in the TeV range which decay into a pair of top quarks. With its large cross section, t-bar t production at the Large Hadron Collider (LHC) offers an excellent opportunity to search for such particles. We present a detailed study of the discovery potential of the CERN Large Hadron Collider for Kaluza-Klein (KK) excitations of the gluon in bulk Randall-Sundrum (RS) models in the t-bar t -> ell^+/- nu b-bar bq-bar q' (ell=e, mu) final state. We utilize final states with one or two tagged b-quarks, and two, three or four jets (including b-jets). Our calculations take into account the finite resolution of detectors, the energy loss due to b-quark decays, the expected reduced b-tagging efficiency at large t-bar t invariant masses, and include the background originating from Wb-bar b+jets, (Wb+W-bar b)+jets, W+jets, and single top + jets production. We derive semi-realistic 5 sigma discovery limits for nine different KK gluon scenarios, and compare them with those for KK gravitons, and a Z_H boson in the Littlest Higgs model. We also analyze the capabilities of the LHC experiments to differentiate between individual KK gluon models and measure the couplings of KK gluons to quarks. We find that, for the parameters and models chosen, KK gluons with masses up to about 4 TeV can be discovered at the LHC. The ability of the LHC to discriminate between different bulk RS models, and to measure the couplings of the KK gluons is found to be highly model dependent. |
hep-ph/0108020 | Arcadi Santamaria | Josep F. Oliver and Arcadi Santamaria | Neutrino masses from operator mixing | 11 pages, 1 figure, revtex | Phys.Rev. D65 (2002) 033003 | 10.1103/PhysRevD.65.033003 | FTUV-01-0802, IFIC/01-41 | hep-ph | null | We show that in theories that reduce, at the Fermi scale, to an extension of
the standard model with two doublets, there can be additional dimension five
operators giving rise to neutrino masses. In particular there exists a singlet
operator which can not generate neutrino masses at tree level but generates
them through operator mixing. Under the assumption that only this operator
appears at tree level we calculate the neutrino mass matrix. It has the Zee
mass matrix structure and leads naturally to bimaximal mixing. However, the
maximal mixing prediction for solar neutrinos is very sharp even when higher
order corrections are considered. To allow for deviations from maximal mixing a
fine tuning is needed in the neutrino mass matrix parameters. However, this
fine tuning relates the departure from maximal mixing in solar neutrino
oscillations with the neutrinoless double beta decay rate.
| [
{
"created": "Thu, 2 Aug 2001 16:34:46 GMT",
"version": "v1"
}
] | 2009-11-07 | [
[
"Oliver",
"Josep F.",
""
],
[
"Santamaria",
"Arcadi",
""
]
] | We show that in theories that reduce, at the Fermi scale, to an extension of the standard model with two doublets, there can be additional dimension five operators giving rise to neutrino masses. In particular there exists a singlet operator which can not generate neutrino masses at tree level but generates them through operator mixing. Under the assumption that only this operator appears at tree level we calculate the neutrino mass matrix. It has the Zee mass matrix structure and leads naturally to bimaximal mixing. However, the maximal mixing prediction for solar neutrinos is very sharp even when higher order corrections are considered. To allow for deviations from maximal mixing a fine tuning is needed in the neutrino mass matrix parameters. However, this fine tuning relates the departure from maximal mixing in solar neutrino oscillations with the neutrinoless double beta decay rate. |
1106.2392 | Thorsten Renk | Thorsten Renk, Jussi Auvinen, Kari J. Eskola, Ulrich Heinz, Hannu
Holopainen, Risto Paatelainen and Chun Shen | Systematics of parton-medium interaction from RHIC to LHC | Talk given at Quark Matter 2011, 22-28 May 2011, Annecy, France | null | 10.1088/0954-3899/38/12/124089 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Despite a wealth of experimental data for high-P_T processes in heavy-ion
collisions, discriminating between different models of hard parton-medium
interactions has been difficult. A key reason is that the pQCD parton spectrum
at RHIC is falling so steeply that distinguishing even a moderate shift in
parton energy from complete parton absorption is essentially impossible. In
essence, energy loss models are effectively only probed in the vicinity of zero
energy loss and, as a result, at RHIC energies only the pathlength dependence
of energy loss offers some discriminating power. At LHC however, this is no
longer the case: Due to the much flatter shape of the parton p_T spectra
originating from 2.76 AGeV collisions, the available data probe much deeper
into the model dynamics. A simultaneous fit of the nuclear suppression at both
RHIC and LHC energies thus has great potential for discriminating between
various models that yield equally good descriptions of RHIC data alone.
| [
{
"created": "Mon, 13 Jun 2011 07:34:29 GMT",
"version": "v1"
}
] | 2015-05-28 | [
[
"Renk",
"Thorsten",
""
],
[
"Auvinen",
"Jussi",
""
],
[
"Eskola",
"Kari J.",
""
],
[
"Heinz",
"Ulrich",
""
],
[
"Holopainen",
"Hannu",
""
],
[
"Paatelainen",
"Risto",
""
],
[
"Shen",
"Chun",
""
]
] | Despite a wealth of experimental data for high-P_T processes in heavy-ion collisions, discriminating between different models of hard parton-medium interactions has been difficult. A key reason is that the pQCD parton spectrum at RHIC is falling so steeply that distinguishing even a moderate shift in parton energy from complete parton absorption is essentially impossible. In essence, energy loss models are effectively only probed in the vicinity of zero energy loss and, as a result, at RHIC energies only the pathlength dependence of energy loss offers some discriminating power. At LHC however, this is no longer the case: Due to the much flatter shape of the parton p_T spectra originating from 2.76 AGeV collisions, the available data probe much deeper into the model dynamics. A simultaneous fit of the nuclear suppression at both RHIC and LHC energies thus has great potential for discriminating between various models that yield equally good descriptions of RHIC data alone. |
0806.2832 | Julia Garayoa | Sacha Davidson (Lyon, IPN), Julia Garayoa (Valencia U. & Valencia U.,
IFIC), Federica Palorini (Lyon, IPN), Nuria Rius (Valencia U. & Valencia U.,
IFIC) | CP Violation in the SUSY Seesaw: Leptogenesis and Low Energy | 30 pages, 7 figures | JHEP 0809:053,2008 | 10.1088/1126-6708/2008/09/053 | LYCEN 2008-06, IFIC/08-28, FTUV-08-0419 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We suppose that the baryon asymmetry is produced by thermal leptogenesis
(with flavour effects), at temperatures $\sim 10^{9} - 10^{10}$ GeV, in the
supersymmetric seesaw with universal and real soft terms. The parameter space
is restricted by assuming that $l_\alpha \to l_\beta \gamma$ processes will be
seen in upcoming experiments. We study the sensitivity of the baryon asymmetry
to the phases of the lepton mixing matrix, and find that leptogenesis can work
for any value of the phases. We also estimate the contribution to the electric
dipole moment of the electron, arising from the seesaw, and find that it is
(just) beyond the sensitivity of next generation experiments ($\lsim 10^{-29}
e$ cm). The fourteen dimensional parameter space is efficiently explored with a
Monte Carlo Markov Chain, which concentrates on the regions of interest.
| [
{
"created": "Tue, 17 Jun 2008 16:36:57 GMT",
"version": "v1"
},
{
"created": "Sat, 28 Jun 2008 20:46:56 GMT",
"version": "v2"
},
{
"created": "Tue, 30 Sep 2008 12:44:00 GMT",
"version": "v3"
}
] | 2009-01-06 | [
[
"Davidson",
"Sacha",
"",
"Lyon, IPN"
],
[
"Garayoa",
"Julia",
"",
"Valencia U. & Valencia U.,\n IFIC"
],
[
"Palorini",
"Federica",
"",
"Lyon, IPN"
],
[
"Rius",
"Nuria",
"",
"Valencia U. & Valencia U.,\n IFIC"
]
] | We suppose that the baryon asymmetry is produced by thermal leptogenesis (with flavour effects), at temperatures $\sim 10^{9} - 10^{10}$ GeV, in the supersymmetric seesaw with universal and real soft terms. The parameter space is restricted by assuming that $l_\alpha \to l_\beta \gamma$ processes will be seen in upcoming experiments. We study the sensitivity of the baryon asymmetry to the phases of the lepton mixing matrix, and find that leptogenesis can work for any value of the phases. We also estimate the contribution to the electric dipole moment of the electron, arising from the seesaw, and find that it is (just) beyond the sensitivity of next generation experiments ($\lsim 10^{-29} e$ cm). The fourteen dimensional parameter space is efficiently explored with a Monte Carlo Markov Chain, which concentrates on the regions of interest. |
2311.14945 | Pouya Bakhti | Pouya Bakhti, Meshkat Rajaee, Seodong Shin | Uncovering Secret Neutrino Interactions at Tau Neutrino Experiments | 16 pages, 6 figures | null | null | null | hep-ph hep-ex | http://creativecommons.org/licenses/by/4.0/ | We investigate the potential of future tau neutrino experiments for
identifying the $\nu_\tau$ appearance in probing secret neutrino interactions.
The reference experiments include the DUNE far detector utilizing the
atmospheric data, which is for the first time in probing the secret
interactions, the Forward Liquid Argon Experiment (FLArE100) detector at the
Forward Physics Facility (FPF), and emulsion detector experiments such as
SND@LHC, AdvSND, FASER$\nu$2, and SND@SHiP. For concreteness, we consider a
reference scenario in which the hidden interactions among the neutrinos are
mediated by a single light gauge boson $Z'$ with a mass at most below the
sub-GeV scale and an interaction strength $g_{\alpha \beta}$ between the active
neutrinos. We confirm that these experiments have the capability to
significantly enhance the current sensitivities on $g_{\alpha \beta }$ for
$m_{Z'} \lesssim 500$ MeV due to the production of high energy neutrinos and
excellent ability to detect tau neutrinos. Our analysis highlights the crucial
role of downward-going DUNE atmospheric data in the search for secret neutrino
interactions because of the rejection of backgrounds dominated in the
upward-going events. Specifically, 10 years of DUNE atmospheric data can
provide the best sensitivities on $g_{\alpha \beta}$ which is about two orders
of magnitude improvement. In addition, the beam-based experiments such as
FLArE100 and FASER$\nu$2 can improve the current constraint on $g_{e\tau}$ and
$g_{\mu\tau}$ by more than an order of magnitude after the full running of the
high luminosity LHC with the integrated luminosity of 3 ab$^{-1}$. For
$g_{e\mu}$ and $g_{ee}$ the SHiP experiment can play the most important role in
the high energy region of $E> few~100$ MeV.
| [
{
"created": "Sat, 25 Nov 2023 06:39:24 GMT",
"version": "v1"
}
] | 2023-11-28 | [
[
"Bakhti",
"Pouya",
""
],
[
"Rajaee",
"Meshkat",
""
],
[
"Shin",
"Seodong",
""
]
] | We investigate the potential of future tau neutrino experiments for identifying the $\nu_\tau$ appearance in probing secret neutrino interactions. The reference experiments include the DUNE far detector utilizing the atmospheric data, which is for the first time in probing the secret interactions, the Forward Liquid Argon Experiment (FLArE100) detector at the Forward Physics Facility (FPF), and emulsion detector experiments such as SND@LHC, AdvSND, FASER$\nu$2, and SND@SHiP. For concreteness, we consider a reference scenario in which the hidden interactions among the neutrinos are mediated by a single light gauge boson $Z'$ with a mass at most below the sub-GeV scale and an interaction strength $g_{\alpha \beta}$ between the active neutrinos. We confirm that these experiments have the capability to significantly enhance the current sensitivities on $g_{\alpha \beta }$ for $m_{Z'} \lesssim 500$ MeV due to the production of high energy neutrinos and excellent ability to detect tau neutrinos. Our analysis highlights the crucial role of downward-going DUNE atmospheric data in the search for secret neutrino interactions because of the rejection of backgrounds dominated in the upward-going events. Specifically, 10 years of DUNE atmospheric data can provide the best sensitivities on $g_{\alpha \beta}$ which is about two orders of magnitude improvement. In addition, the beam-based experiments such as FLArE100 and FASER$\nu$2 can improve the current constraint on $g_{e\tau}$ and $g_{\mu\tau}$ by more than an order of magnitude after the full running of the high luminosity LHC with the integrated luminosity of 3 ab$^{-1}$. For $g_{e\mu}$ and $g_{ee}$ the SHiP experiment can play the most important role in the high energy region of $E> few~100$ MeV. |
hep-ph/0403055 | Zack Sullivan | Zack Sullivan | Faster Parton Distribution Evaluation in Monte Carlos | 7 pages | null | null | null | hep-ph hep-ex | null | I recommend a few trivial changes to the routines that evaluate CTEQ parton
distribution functions. These changes allow modern compilers to optimize the
evaluation routines, while having no quantitative effect on the results.
Computation time is reduced by a factor of 2 in matrix-element calculations,
and by 1.3-1.5 in the showering Monte Carlo event generators with fast detector
effects included. The results suggest that additional time should be invested
in optimizing these routines.
| [
{
"created": "Thu, 4 Mar 2004 23:20:12 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Sullivan",
"Zack",
""
]
] | I recommend a few trivial changes to the routines that evaluate CTEQ parton distribution functions. These changes allow modern compilers to optimize the evaluation routines, while having no quantitative effect on the results. Computation time is reduced by a factor of 2 in matrix-element calculations, and by 1.3-1.5 in the showering Monte Carlo event generators with fast detector effects included. The results suggest that additional time should be invested in optimizing these routines. |
2210.01446 | Sorin Ciulli | Alexandre Ciulli and Sorin Ciulli | On the possible implications of Dark Matter in the rings of Saturn: a
conjecture | 14 pages, 9 figures | null | null | null | hep-ph astro-ph.EP gr-qc math-ph math.MP | http://creativecommons.org/licenses/by/4.0/ | In this article we discuss some consequences of the well-known proposition of
Fritz Zwicky [1], published in the nineteen thirties, that Dark Matter `mimics'
the inertia-gravitational behaviour of usual matter. In particular, we consider
some special dynamical regions such as those of the Ring Systems of the gaseous
giants at the edge of the Planetary System. This article is a continuation of
an earlier paper [2], where it was shown that gravitationally interacting
particles may remain near the Lagrange Points L4 and L5 for many thousands of
years. This provides enough time for the Dark Matter, if present there, to
interact with the usual matter. We discuss also a number of questions related
to places which might be considered singular in the mathematical sense.
| [
{
"created": "Tue, 4 Oct 2022 08:17:38 GMT",
"version": "v1"
}
] | 2022-10-05 | [
[
"Ciulli",
"Alexandre",
""
],
[
"Ciulli",
"Sorin",
""
]
] | In this article we discuss some consequences of the well-known proposition of Fritz Zwicky [1], published in the nineteen thirties, that Dark Matter `mimics' the inertia-gravitational behaviour of usual matter. In particular, we consider some special dynamical regions such as those of the Ring Systems of the gaseous giants at the edge of the Planetary System. This article is a continuation of an earlier paper [2], where it was shown that gravitationally interacting particles may remain near the Lagrange Points L4 and L5 for many thousands of years. This provides enough time for the Dark Matter, if present there, to interact with the usual matter. We discuss also a number of questions related to places which might be considered singular in the mathematical sense. |
hep-ph/0505040 | Youngshin Kwon | Youngshin Kwon (RCNP, Osaka Univ., Japan and Dept. of Phys., Yonsei
Univ., Korea), Atsushi Hosaka (RCNP, Osaka Univ., Japan), Su Houng Lee (Dept.
of Phys., Yonsei Univ., Korea) | Non-interacting KN contribution in the QCD sum rule for the pentaquark
Theta^+(1540) | 7 pages, 5 figures, Talk given at Quark Nuclear Physics 2005 at
Pyongchang, Korea, February 22-24, 2005 | null | null | null | hep-ph | null | We perform a QCD sum rule analysis for the pentaquark baryon Theta^+ with the
non-interacting $KN$ contribution treated carefully. The coupling of the
Theta^+ current to the $KN$ state is evaluated by applying the soft kaon
theorem and vacuum saturation. When using a five-quark current including scalar
and pseudo-scalar diquarks, the KN contribution turns out not to be very
important and the previous result of the negative parity Theta^+ is reproduced
again. The Borel analysis of the correlation function for Theta^+ with the KN
continuum states subtracted yields the mass of the J^P= 1/2^- Theta^+ around
1.5 GeV.
| [
{
"created": "Fri, 6 May 2005 07:31:42 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Kwon",
"Youngshin",
"",
"RCNP, Osaka Univ., Japan and Dept. of Phys., Yonsei\n Univ., Korea"
],
[
"Hosaka",
"Atsushi",
"",
"RCNP, Osaka Univ., Japan"
],
[
"Lee",
"Su Houng",
"",
"Dept.\n of Phys., Yonsei Univ., Korea"
]
] | We perform a QCD sum rule analysis for the pentaquark baryon Theta^+ with the non-interacting $KN$ contribution treated carefully. The coupling of the Theta^+ current to the $KN$ state is evaluated by applying the soft kaon theorem and vacuum saturation. When using a five-quark current including scalar and pseudo-scalar diquarks, the KN contribution turns out not to be very important and the previous result of the negative parity Theta^+ is reproduced again. The Borel analysis of the correlation function for Theta^+ with the KN continuum states subtracted yields the mass of the J^P= 1/2^- Theta^+ around 1.5 GeV. |
1102.3480 | Davison E. Soper | Davison E. Soper and Michael Spannowsky | Finding physics signals with shower deconstruction | Revised version with improvements to the algorithm and a
normalization error corrected. Performance is improved compared to version 1 | null | 10.1103/PhysRevD.84.074002 | null | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We introduce shower deconstruction, a method to look for new physics in a
hadronic environment. The method aims to be a full information approach using
small jets. It assigns to each event a number chi that is an estimate of the
ratio of the probability for a signal process to produce that event to the
probability for a background process to produce that event. The analytic
functions we derive to calculate these probabilities mimic what full event
generators like Pythia or Herwig do and can be depicted in a diagrammatic way.
As an example, we apply this method to a boosted Higgs boson produced in
association with a Z-boson and show that this method can be useful to
discriminate this signal from the Z+jets background.
| [
{
"created": "Thu, 17 Feb 2011 03:04:56 GMT",
"version": "v1"
},
{
"created": "Tue, 2 Aug 2011 18:38:18 GMT",
"version": "v2"
}
] | 2013-05-29 | [
[
"Soper",
"Davison E.",
""
],
[
"Spannowsky",
"Michael",
""
]
] | We introduce shower deconstruction, a method to look for new physics in a hadronic environment. The method aims to be a full information approach using small jets. It assigns to each event a number chi that is an estimate of the ratio of the probability for a signal process to produce that event to the probability for a background process to produce that event. The analytic functions we derive to calculate these probabilities mimic what full event generators like Pythia or Herwig do and can be depicted in a diagrammatic way. As an example, we apply this method to a boosted Higgs boson produced in association with a Z-boson and show that this method can be useful to discriminate this signal from the Z+jets background. |
1006.3231 | Debasish Majumdar | Abhijit Bandyopadhyay, Debasish Majumdar | On Diurnal and Annual Variations of Directional Detection Rates of Dark
Matter | 11 pages, 17 figures | The Astrophysical Journal, 746:107 (14pp), 2012 | 10.1088/0004-637X/746/1/107 | SINP/APC-2010/01 | hep-ph astro-ph.CO | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Direction sensitive direct detection of Weakly Interacting Massive Particles
(WIMPs) as dark matter would provide an unambiguous non-gravitational signature
of dark matter (DM). The diurnal variation of DM signal due to earth's rotation
around its own axis can be a significant signature for galactic WIMPs. Because
of particular orientation of earth's axis of rotation with respect to WIMP wind
direction, the apparent direction of WIMP wind as observed at a detector can
alter widely over a day. In this work we calculate the directional detection
rates with their daily and yearly modulations in earth-bound dark matter
experiments considering detailed features of the geometry and dynamics of the
earth-sun system along with the solar motion in galactic frame. A separate halo
model namely the dark disc model other than the usual standard halo model for
dark matter halo is also considered and the results for two models are
compared. We demonstrate the results for two types of gas detectors namely
DRIFT (target material CS2) and NEWAGE (target material CF4) that use Time
Projection Chamber techniques for measuring directionality of the recoil
nucleus. The WIMP mass and recoil energy dependence of the daily variation of
event rates are computed for specific detector and the sensitive ranges of mass
and recoil energies for the considered detector are probed.
| [
{
"created": "Wed, 16 Jun 2010 14:27:47 GMT",
"version": "v1"
},
{
"created": "Fri, 13 Apr 2012 07:20:48 GMT",
"version": "v2"
}
] | 2012-04-16 | [
[
"Bandyopadhyay",
"Abhijit",
""
],
[
"Majumdar",
"Debasish",
""
]
] | Direction sensitive direct detection of Weakly Interacting Massive Particles (WIMPs) as dark matter would provide an unambiguous non-gravitational signature of dark matter (DM). The diurnal variation of DM signal due to earth's rotation around its own axis can be a significant signature for galactic WIMPs. Because of particular orientation of earth's axis of rotation with respect to WIMP wind direction, the apparent direction of WIMP wind as observed at a detector can alter widely over a day. In this work we calculate the directional detection rates with their daily and yearly modulations in earth-bound dark matter experiments considering detailed features of the geometry and dynamics of the earth-sun system along with the solar motion in galactic frame. A separate halo model namely the dark disc model other than the usual standard halo model for dark matter halo is also considered and the results for two models are compared. We demonstrate the results for two types of gas detectors namely DRIFT (target material CS2) and NEWAGE (target material CF4) that use Time Projection Chamber techniques for measuring directionality of the recoil nucleus. The WIMP mass and recoil energy dependence of the daily variation of event rates are computed for specific detector and the sensitive ranges of mass and recoil energies for the considered detector are probed. |
1111.6838 | Korinna Zapp | Korinna C. Zapp, Frank Krauss, Urs A. Wiedemann | Explaining jet quenching with perturbative QCD alone | 4 pages, 3 figures, v2: extended fig. 3 to large pt + minor changes | null | null | IPPP/11/41; DCPT/11/82; MCnet-11-26; CERN-PH-TH/2011-299 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present a new formulation of jet quenching in perturbative QCD beyond the
eikonal approximation. Multiple scattering in the medium is modelled through
infra-red-continued (2 -> 2) scattering matrix elements in QCD and the parton
shower describing further emissions. The interplay between these processes is
arranged in terms of a formation time constraint such that coherent emissions
can be treated consistently. Emerging partons are hadronised by the Lund string
model, tuned to describe LEP data in conjunction with the parton shower. Based
on this picture we obtain a good description of the nuclear modification factor
R_AA at RHIC and LHC.
| [
{
"created": "Tue, 29 Nov 2011 15:20:07 GMT",
"version": "v1"
},
{
"created": "Fri, 30 Mar 2012 21:37:52 GMT",
"version": "v2"
}
] | 2012-04-03 | [
[
"Zapp",
"Korinna C.",
""
],
[
"Krauss",
"Frank",
""
],
[
"Wiedemann",
"Urs A.",
""
]
] | We present a new formulation of jet quenching in perturbative QCD beyond the eikonal approximation. Multiple scattering in the medium is modelled through infra-red-continued (2 -> 2) scattering matrix elements in QCD and the parton shower describing further emissions. The interplay between these processes is arranged in terms of a formation time constraint such that coherent emissions can be treated consistently. Emerging partons are hadronised by the Lund string model, tuned to describe LEP data in conjunction with the parton shower. Based on this picture we obtain a good description of the nuclear modification factor R_AA at RHIC and LHC. |
hep-ph/9711505 | Colin Froggatt | C. D. Froggatt | The Fermion Mass Hierarchy and Neutrino Mixing Problem | 8 page LaTeX file plus FEYNMAN style file; to appear in the
Proceedings of the 8th Lomonosov Conference on Elementary Particle Physics,
Moscow, 25-30 August 1997 | null | null | GUTPA/97/11/2 | hep-ph | null | The fermion mass problem is briefly reviewed. The observed hierarchy of quark
and charged lepton masses strongly suggests the existence of an approximately
conserved chiral flavour symmetry beyond the Standard Model. It is argued that
in models of this type, the requirement of a natural explanation for both the
atmospheric and solar neutrino problems leads to an essentially unique picture
of neutrino masses and mixing angles. The anti-grand unification model is used
as an explicit example to illustrate these ideas.
| [
{
"created": "Fri, 28 Nov 1997 10:34:14 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Froggatt",
"C. D.",
""
]
] | The fermion mass problem is briefly reviewed. The observed hierarchy of quark and charged lepton masses strongly suggests the existence of an approximately conserved chiral flavour symmetry beyond the Standard Model. It is argued that in models of this type, the requirement of a natural explanation for both the atmospheric and solar neutrino problems leads to an essentially unique picture of neutrino masses and mixing angles. The anti-grand unification model is used as an explicit example to illustrate these ideas. |
2406.12961 | Juan Rojo | Juan Cruz-Martinez, Stefano Forte, Niccolo Laurenti, Tanjona R.
Rabemananjara, Juan Rojo | LO, NLO, and NNLO Parton Distributions for LHC Event Generators | 14 pages, 9 figures, PDF sets available from
https://nnpdf.mi.infn.it/nnpdf4-0-mc/ | null | null | CERN-TH-2024-080, TIF-UNIMI-2024-4 | hep-ph hep-ex | http://creativecommons.org/licenses/by/4.0/ | We present NNPDF4.0MC, a variant of the NNPDF4.0 set of parton distributions
(PDFs) at LO, NLO and NNLO, with and without inclusion of the photon PDF,
suitable for use with Monte Carlo (MC) event generators, which require PDFs to
satisfy additional constraints in comparison to standard PDF sets. These
requirements include PDF positivity down to a low scale $Q\sim 1$ GeV, smooth
extrapolation in the very small and large $x$ regions, and numerically stable
results even in extreme regions of phase space for all PDFs. We compare the
NNPDF4.0MC PDFs to their baseline NNPDF4.0 counterparts, and to the NNPDF2.3LO
set entering the Monash tune of the Pythia8 event generator. We briefly assess
the phenomenological impact of these PDFs on the cross-sections for hard and
soft QCD processes at the LHC.
| [
{
"created": "Tue, 18 Jun 2024 18:00:00 GMT",
"version": "v1"
}
] | 2024-06-21 | [
[
"Cruz-Martinez",
"Juan",
""
],
[
"Forte",
"Stefano",
""
],
[
"Laurenti",
"Niccolo",
""
],
[
"Rabemananjara",
"Tanjona R.",
""
],
[
"Rojo",
"Juan",
""
]
] | We present NNPDF4.0MC, a variant of the NNPDF4.0 set of parton distributions (PDFs) at LO, NLO and NNLO, with and without inclusion of the photon PDF, suitable for use with Monte Carlo (MC) event generators, which require PDFs to satisfy additional constraints in comparison to standard PDF sets. These requirements include PDF positivity down to a low scale $Q\sim 1$ GeV, smooth extrapolation in the very small and large $x$ regions, and numerically stable results even in extreme regions of phase space for all PDFs. We compare the NNPDF4.0MC PDFs to their baseline NNPDF4.0 counterparts, and to the NNPDF2.3LO set entering the Monash tune of the Pythia8 event generator. We briefly assess the phenomenological impact of these PDFs on the cross-sections for hard and soft QCD processes at the LHC. |
hep-ph/9402249 | null | T. D. Cohen and J. Milana | Model Independent Extraction of $|V_{\rm bc}|$ Without Heavy Quark
Symmetry | 10 pages revtex3 manuscript. No figures, U. of MD PP #94--086. With
our apologies, some innocuous errors corrected and some references added that
had been brought to our attention | Phys.Rev.D50:21-25,1994 | 10.1103/PhysRevD.50.R21 | null | hep-ph | null | A new method to extract $|V_{\rm bc}|$ is proposed based on a sum--rule for
semileptonic decays of the $B$ meson. The method relies on much weaker
assumptions than previous approaches which are based on heavy--quark symmetry.
This sum--rule only relies on the assumption that the virtual $c \overline{c}$
pair content of the $B$ meson can be neglected. The extraction of the CKM
matrix element also requires that the sum--rule saturates in the kinematically
accessible region.
| [
{
"created": "Tue, 8 Feb 1994 17:08:58 GMT",
"version": "v1"
},
{
"created": "Wed, 16 Feb 1994 21:32:05 GMT",
"version": "v2"
}
] | 2010-11-01 | [
[
"Cohen",
"T. D.",
""
],
[
"Milana",
"J.",
""
]
] | A new method to extract $|V_{\rm bc}|$ is proposed based on a sum--rule for semileptonic decays of the $B$ meson. The method relies on much weaker assumptions than previous approaches which are based on heavy--quark symmetry. This sum--rule only relies on the assumption that the virtual $c \overline{c}$ pair content of the $B$ meson can be neglected. The extraction of the CKM matrix element also requires that the sum--rule saturates in the kinematically accessible region. |
1511.04107 | Fatemeh Elahi | Fatemeh Elahi and Adam Martin | Constraints on $L_\mu - L_\tau$ interactions at the LHC and beyond | version accepted for publication in PRD | Phys. Rev. D 93, 015022 (2016) | 10.1103/PhysRevD.93.015022 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this paper we examine the constraints dedicated LHC multi lepton searches
can place on $Z'$ bosons coming from gauged muon number minus tau number,
$L_{\mu}-L_{\tau}$. As the $L_{\mu}-L_{\tau}$ gauge boson does not couple to
proton constituents or electrons at tree level, the current bounds are fairly
loose, especially for $M_{Z'} \gtrsim 1\, \rm GeV$. For $2m_{\mu} < M_{Z'} <
M_Z/2$ we develop search strategies using the $pp \rightarrow Z \to 4\, \mu$
channel. The cleanliness of the final state, combined with the fact that $pp
\to Z \to 4 e$, $Z \to 2e\,2\mu$ can be used as background control samples,
allow us to spot $L_{\mu}-L_{\tau}$ $Z'$ with couplings $\mathcal O(10^{-3})$
times the Standard Model couplings. For lighter $Z'$, we propose the mode $pp
\rightarrow 2\mu + \displaystyle{\not} E_T$. The presence of missing energy
means there is a wider set of backgrounds to consider in this final state, such
as Drell-Yan production of leptonically decaying $\tau$ pairs, however we find
these can be controlled with careful cuts. Combining the $4\, \mu$ and $2\,\mu
+ \displaystyle{\not} E_T$ modes, we find that with $\sim3 \, \text{ab}^{-1}$
of integrated luminosity we are sensitive to couplings $g_{Z'} \gtrsim 0.005\,
g_1$ and $0.5\, \rm GeV \le M_{Z'} \le 40\, \rm GeV$ and $g_{Z'} \gtrsim
0.001\, g_1$ for $M_{Z'} < 2\, m_{\mu}$. This region includes the parameter
space where $L_{\mu}-L_{\tau}$ models can ameliorate the muon $g-2$ anomaly. We
repeat these analyses at a future $e^+e^-$ Z-factory, where we find improved
sensitivity. Specifically, given $2.6\, \rm ab^{-1}$ of luminosity, we can
exclude $g_{Z'} \gtrsim 0.001\, g_1$ for $2\, m_{\mu} \le M_{Z'} \le M_Z/2$.
| [
{
"created": "Thu, 12 Nov 2015 21:59:15 GMT",
"version": "v1"
},
{
"created": "Wed, 13 Jan 2016 22:07:27 GMT",
"version": "v2"
}
] | 2016-02-03 | [
[
"Elahi",
"Fatemeh",
""
],
[
"Martin",
"Adam",
""
]
] | In this paper we examine the constraints dedicated LHC multi lepton searches can place on $Z'$ bosons coming from gauged muon number minus tau number, $L_{\mu}-L_{\tau}$. As the $L_{\mu}-L_{\tau}$ gauge boson does not couple to proton constituents or electrons at tree level, the current bounds are fairly loose, especially for $M_{Z'} \gtrsim 1\, \rm GeV$. For $2m_{\mu} < M_{Z'} < M_Z/2$ we develop search strategies using the $pp \rightarrow Z \to 4\, \mu$ channel. The cleanliness of the final state, combined with the fact that $pp \to Z \to 4 e$, $Z \to 2e\,2\mu$ can be used as background control samples, allow us to spot $L_{\mu}-L_{\tau}$ $Z'$ with couplings $\mathcal O(10^{-3})$ times the Standard Model couplings. For lighter $Z'$, we propose the mode $pp \rightarrow 2\mu + \displaystyle{\not} E_T$. The presence of missing energy means there is a wider set of backgrounds to consider in this final state, such as Drell-Yan production of leptonically decaying $\tau$ pairs, however we find these can be controlled with careful cuts. Combining the $4\, \mu$ and $2\,\mu + \displaystyle{\not} E_T$ modes, we find that with $\sim3 \, \text{ab}^{-1}$ of integrated luminosity we are sensitive to couplings $g_{Z'} \gtrsim 0.005\, g_1$ and $0.5\, \rm GeV \le M_{Z'} \le 40\, \rm GeV$ and $g_{Z'} \gtrsim 0.001\, g_1$ for $M_{Z'} < 2\, m_{\mu}$. This region includes the parameter space where $L_{\mu}-L_{\tau}$ models can ameliorate the muon $g-2$ anomaly. We repeat these analyses at a future $e^+e^-$ Z-factory, where we find improved sensitivity. Specifically, given $2.6\, \rm ab^{-1}$ of luminosity, we can exclude $g_{Z'} \gtrsim 0.001\, g_1$ for $2\, m_{\mu} \le M_{Z'} \le M_Z/2$. |
1412.4899 | Ayon Patra Dr. | Sin Kyu Kang and Ayon Patra | keV Sterile Neutrino Dark Matter and Low Scale Leptogenesis | 15 pages, 3 figures | null | 10.3938/jkps.69.1375 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We consider a simple extension of the Standard Model to consistently explain
the observation of a peak in the galactic X-ray spectrum at 3.55 keV and the
light neutrino masses along with the baryon asymmetry of the universe. The
baryon asymmetry is generated through leptogenesis, the lepton asymmetry being
generated by the decay of a heavy neutrino with TeV mass scale. The extra
singlet fermion introduced in the model can be identified as a dark matter
candidate of mass 7.1 keV. It decays with a lifetime much larger than the age
of the universe, producing a final state photon. The Yukawa interactions
between the extra singlet neutrino and a heavier right-handed neutrino play a
crucial role in simultaneously achieving low scale leptogenesis and relic
density of the keV dark matter candidate.
| [
{
"created": "Tue, 16 Dec 2014 07:41:06 GMT",
"version": "v1"
},
{
"created": "Fri, 26 Dec 2014 06:48:25 GMT",
"version": "v2"
}
] | 2018-01-17 | [
[
"Kang",
"Sin Kyu",
""
],
[
"Patra",
"Ayon",
""
]
] | We consider a simple extension of the Standard Model to consistently explain the observation of a peak in the galactic X-ray spectrum at 3.55 keV and the light neutrino masses along with the baryon asymmetry of the universe. The baryon asymmetry is generated through leptogenesis, the lepton asymmetry being generated by the decay of a heavy neutrino with TeV mass scale. The extra singlet fermion introduced in the model can be identified as a dark matter candidate of mass 7.1 keV. It decays with a lifetime much larger than the age of the universe, producing a final state photon. The Yukawa interactions between the extra singlet neutrino and a heavier right-handed neutrino play a crucial role in simultaneously achieving low scale leptogenesis and relic density of the keV dark matter candidate. |
1908.04208 | Raghunath Sahoo | Rutuparna Rath, Arvind Khuntia, Raghunath Sahoo, and Jean Cleymans | Event multiplicity, transverse momentum and energy dependence of charged
particle production, and system thermodynamics in $pp$ collisions at the
Large Hadron Collider | Same as the published version | J. Phys. G: Nucl. Part. Phys. 47 (2020) 055111 | 10.1088/1361-6471/ab783b | null | hep-ph hep-ex nucl-ex nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In the present work, we study the recent collision energy and multiplicity
dependence of the charged particle transverse momentum spectra as measured by
the ALICE collaboration in $pp$ collisions at $\sqrt{s}$ = 5.02 and 13 TeV
using the non-extensive Tsallis distribution and the Boltzmann-Gibbs Blast Wave
(BGBW) model. A thermodynamically consistent form of the Tsallis distribution
is used to extract the kinetic freeze-out parameters from the transverse
momentum spectra of charged particles at mid-rapidity. In addition, a
comprehensive study of fitting range dependence of transverse momentum spectra
on the freeze-out parameters is done using Tsallis statistics. The
applicability of BGBW model is verified by fitting the transverse momentum
spectra of the bulk part ($\sim 2.5~ {\rm GeV}/c$)for both 5.02 and 13 TeV
energies and also in different multiplicity classes. The radial flow, $<\beta>$
is almost independent of collision energy and multiplicity whereas the behavior
of kinetic freeze-out temperature significantly depends on multiplicity
classes. It is found that the Tsallis distribution generally leads to a better
description for the complete transverse momentum spectra whereas the BGBW model
explains the bulk part of the system.
| [
{
"created": "Mon, 12 Aug 2019 15:38:42 GMT",
"version": "v1"
},
{
"created": "Thu, 9 Apr 2020 15:16:14 GMT",
"version": "v2"
}
] | 2020-04-10 | [
[
"Rath",
"Rutuparna",
""
],
[
"Khuntia",
"Arvind",
""
],
[
"Sahoo",
"Raghunath",
""
],
[
"Cleymans",
"Jean",
""
]
] | In the present work, we study the recent collision energy and multiplicity dependence of the charged particle transverse momentum spectra as measured by the ALICE collaboration in $pp$ collisions at $\sqrt{s}$ = 5.02 and 13 TeV using the non-extensive Tsallis distribution and the Boltzmann-Gibbs Blast Wave (BGBW) model. A thermodynamically consistent form of the Tsallis distribution is used to extract the kinetic freeze-out parameters from the transverse momentum spectra of charged particles at mid-rapidity. In addition, a comprehensive study of fitting range dependence of transverse momentum spectra on the freeze-out parameters is done using Tsallis statistics. The applicability of BGBW model is verified by fitting the transverse momentum spectra of the bulk part ($\sim 2.5~ {\rm GeV}/c$)for both 5.02 and 13 TeV energies and also in different multiplicity classes. The radial flow, $<\beta>$ is almost independent of collision energy and multiplicity whereas the behavior of kinetic freeze-out temperature significantly depends on multiplicity classes. It is found that the Tsallis distribution generally leads to a better description for the complete transverse momentum spectra whereas the BGBW model explains the bulk part of the system. |
2302.12382 | Ahmad Jafar Arifi | Ahmad Jafar Arifi, Parada. T. P. Hutauruk, Kazuo Tsushima | In-medium properties of the light and heavy-light mesons in a
light-front quark model | 17 pages, 11 figures | Phys. Rev. D 107, 114010 (2023) | 10.1103/PhysRevD.107.114010 | LFTC-23-1/74 | hep-ph hep-ex nucl-ex nucl-th | http://creativecommons.org/licenses/by/4.0/ | We investigate the in-medium properties of pseudoscalar and vector mesons
with the light-light and heavy-light quarks in a light-front quark model, using
the in-medium quark properties computed by the quark-meson coupling model. Both
models are constructed on an equal footing with the constituent quark degree of
freedom. Here, we particularly focus on the weak decay constants and
distribution amplitudes (DAs) of the mesons in symmetric nuclear matter. We
find that the weak decay constants decrease as nuclear density increases for
$\pi$, $K$, $D$, and $B$ pseudoscalar as well as $\rho$, $K^{*}$, $D^{*}$, and
$B^*$ vector mesons, where their properties in free space have good agreement
with the available experimental and lattice QCD data. A larger reduction is
found for the light-light quark pseudoscalar mesons, while a smaller reduction
is found for the heavy-light quark vector mesons, in particular, with the
bottom quark. We discuss the effect of the vector potential on the weak decay
constants and present our predictions for the in-medium modifications of DAs.
Also, a comparison with the free space lattice QCD data is made.
| [
{
"created": "Fri, 24 Feb 2023 01:01:55 GMT",
"version": "v1"
},
{
"created": "Mon, 19 Jun 2023 11:40:30 GMT",
"version": "v2"
}
] | 2023-06-21 | [
[
"Arifi",
"Ahmad Jafar",
""
],
[
"Hutauruk",
"Parada. T. P.",
""
],
[
"Tsushima",
"Kazuo",
""
]
] | We investigate the in-medium properties of pseudoscalar and vector mesons with the light-light and heavy-light quarks in a light-front quark model, using the in-medium quark properties computed by the quark-meson coupling model. Both models are constructed on an equal footing with the constituent quark degree of freedom. Here, we particularly focus on the weak decay constants and distribution amplitudes (DAs) of the mesons in symmetric nuclear matter. We find that the weak decay constants decrease as nuclear density increases for $\pi$, $K$, $D$, and $B$ pseudoscalar as well as $\rho$, $K^{*}$, $D^{*}$, and $B^*$ vector mesons, where their properties in free space have good agreement with the available experimental and lattice QCD data. A larger reduction is found for the light-light quark pseudoscalar mesons, while a smaller reduction is found for the heavy-light quark vector mesons, in particular, with the bottom quark. We discuss the effect of the vector potential on the weak decay constants and present our predictions for the in-medium modifications of DAs. Also, a comparison with the free space lattice QCD data is made. |
1605.08012 | Fredrick Olness | D.B. Clark, E. Godat, F.I. Olness | ManeParse: a Mathematica reader for Parton Distribution Functions | 15 pages, 16 figures, 3 tables, pdflatex. Version 2: Update to
published CPC version. Source files available at: http://ncteq.hepforge.org | Comput.Phys.Commun. 216 (2017) 126-137 | 10.1016/j.cpc.2017.03.004 | NSF-KITP-16-032, SMU-HEP-16-05 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Parton Distribution Functions (PDFs) are essential non-perturbative inputs
for calculation of any observable with hadronic initial states. These PDFs are
released by individual groups as discrete grids as a function of the Bjorken-x
and energy scale Q. The LHAPDF project at HepForge maintains a repository of
PDFs from various groups in a new standardized LHAPDF6 format, as well as older
formats such as the CTEQ PDS grid format. ManeParse is a package that provides
PDFs within the Mathematica framework to facilitate calculating and plotting.
The program is self-contained so there are no external links to any Fortran, C
or C++ programs. The package includes the option to use the built-in
Mathematica interpolation or a custom cubic Lagrange interpolation routine
which allows for flexibility in the extrapolation (particularly at small x
values). ManeParse is fast enough to enable simple calculations (involving even
one or two integrations) to be easily computed in the Mathematica framework.
| [
{
"created": "Wed, 25 May 2016 19:20:06 GMT",
"version": "v1"
},
{
"created": "Fri, 4 Oct 2019 23:52:46 GMT",
"version": "v2"
}
] | 2019-10-08 | [
[
"Clark",
"D. B.",
""
],
[
"Godat",
"E.",
""
],
[
"Olness",
"F. I.",
""
]
] | Parton Distribution Functions (PDFs) are essential non-perturbative inputs for calculation of any observable with hadronic initial states. These PDFs are released by individual groups as discrete grids as a function of the Bjorken-x and energy scale Q. The LHAPDF project at HepForge maintains a repository of PDFs from various groups in a new standardized LHAPDF6 format, as well as older formats such as the CTEQ PDS grid format. ManeParse is a package that provides PDFs within the Mathematica framework to facilitate calculating and plotting. The program is self-contained so there are no external links to any Fortran, C or C++ programs. The package includes the option to use the built-in Mathematica interpolation or a custom cubic Lagrange interpolation routine which allows for flexibility in the extrapolation (particularly at small x values). ManeParse is fast enough to enable simple calculations (involving even one or two integrations) to be easily computed in the Mathematica framework. |
1303.6929 | Danning Li | Danning Li and Mei Huang | Dynamical holographic QCD model for glueball and light meson spectra | 49 pages, 23 figures, version accepted by JHEP | JHEP11(2013)088 | 10.1007/JHEP11(2013)088 | null | hep-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this work, we offer a dynamical soft-wall model to describe the
gluodynamics and chiral dynamics in one systematical framework. We firstly
construct a quenched dynamical holographic QCD (hQCD) model in the
graviton-dilaton framework for the pure gluon system, then develop a dynamical
hQCD model for the two flavor system in the graviton-dilaton-scalar framework
by adding light flavors on the gluodynamical background. For two forms of
dilaton background field $\Phi=\mu_G^2z^2$ and
$\Phi=\mu_G^2z^2\tanh(\mu_{G^2}^4z^2/\mu_G^2)$, the quadratic correction to
dilaton background field at infrared encodes important non-perturbative
gluodynamics and naturally induces a deformed warp factor of the metric. By
self-consistently solving the deformed metric induced by the dilaton background
field, we find that the scalar glueball spectra in the quenched dynamical model
is in very well agreement with lattice data. For two flavor system in the
graviton-dilaton-scalar framework, the deformed metric is self-consistently
solved by considering both the chiral condensate and nonperturbative
gluodynamics in the vacuum, which are responsible for the chiral symmetry
breaking and linear confinement, respectively. It is found that the mixing
between the chiral condensate and gluon condensate is important to produce the
correct light flavor meson spectra. The pion form factor and the vector
couplings are also investigated in the dynamical hQCD model. Besides, we give
the criteria for the existence of linear quark potential from the metric
structure, and show a negative quadratic dilaton background field is not
favored in the graviton-dilaton framework.
| [
{
"created": "Wed, 27 Mar 2013 19:08:22 GMT",
"version": "v1"
},
{
"created": "Wed, 30 Oct 2013 01:41:57 GMT",
"version": "v2"
}
] | 2013-11-15 | [
[
"Li",
"Danning",
""
],
[
"Huang",
"Mei",
""
]
] | In this work, we offer a dynamical soft-wall model to describe the gluodynamics and chiral dynamics in one systematical framework. We firstly construct a quenched dynamical holographic QCD (hQCD) model in the graviton-dilaton framework for the pure gluon system, then develop a dynamical hQCD model for the two flavor system in the graviton-dilaton-scalar framework by adding light flavors on the gluodynamical background. For two forms of dilaton background field $\Phi=\mu_G^2z^2$ and $\Phi=\mu_G^2z^2\tanh(\mu_{G^2}^4z^2/\mu_G^2)$, the quadratic correction to dilaton background field at infrared encodes important non-perturbative gluodynamics and naturally induces a deformed warp factor of the metric. By self-consistently solving the deformed metric induced by the dilaton background field, we find that the scalar glueball spectra in the quenched dynamical model is in very well agreement with lattice data. For two flavor system in the graviton-dilaton-scalar framework, the deformed metric is self-consistently solved by considering both the chiral condensate and nonperturbative gluodynamics in the vacuum, which are responsible for the chiral symmetry breaking and linear confinement, respectively. It is found that the mixing between the chiral condensate and gluon condensate is important to produce the correct light flavor meson spectra. The pion form factor and the vector couplings are also investigated in the dynamical hQCD model. Besides, we give the criteria for the existence of linear quark potential from the metric structure, and show a negative quadratic dilaton background field is not favored in the graviton-dilaton framework. |
hep-ph/0201140 | Subir Sarkar | Subir Sarkar (Oxford) | New results in cosmology | 15 pages (JHEP LaTeX), 12 figures; Plenary talk at EPS-HEP 2001,
Budapest, 12-18 July 2001; Revisions: refs updated, typos fixed | EPS International Conference on High Energy Physics, Budapest,
2001 (D. Horvath, P. Levai, A. Patkos,eds.), JHEP Proceedings Section,
PrHEP-hep2001/299 | null | null | hep-ph astro-ph hep-th | null | From an observational perspective cosmology is today in excellent shape -
advances in instrumentation and data processing have enabled us to study the
universe in detail back to when the first galaxies formed, map the fluctuations
in the cosmic microwave background which provide a measure of the overall
geometry, and reconstruct the thermal history reliably back to at least the
primordial nucleosynthesis era. However recent deep studies of the Hubble
expansion rate have suggested that the universe is accelerating, driven by some
form of `dark' (vacuum) energy. If true, this implies a new energy scale in
Nature of order 0.001 eV, well below any known scale of fundamental physics.
This has refocussed attention on the notorious cosmological constant problem at
the interface of general relativity and quantum field theory. It is possible
that the resolution of this situation will require fundamental modifications to
our ideas about gravity.
| [
{
"created": "Tue, 15 Jan 2002 20:38:36 GMT",
"version": "v1"
},
{
"created": "Sun, 14 Apr 2002 13:31:38 GMT",
"version": "v2"
}
] | 2007-05-23 | [
[
"Sarkar",
"Subir",
"",
"Oxford"
]
] | From an observational perspective cosmology is today in excellent shape - advances in instrumentation and data processing have enabled us to study the universe in detail back to when the first galaxies formed, map the fluctuations in the cosmic microwave background which provide a measure of the overall geometry, and reconstruct the thermal history reliably back to at least the primordial nucleosynthesis era. However recent deep studies of the Hubble expansion rate have suggested that the universe is accelerating, driven by some form of `dark' (vacuum) energy. If true, this implies a new energy scale in Nature of order 0.001 eV, well below any known scale of fundamental physics. This has refocussed attention on the notorious cosmological constant problem at the interface of general relativity and quantum field theory. It is possible that the resolution of this situation will require fundamental modifications to our ideas about gravity. |
2005.00459 | Soumya Bhattacharyya | Soumya Bhattacharyya (TIFR Mumbai) and Basudeb Dasgupta (TIFR Mumbai) | Fast Neutrino Flavor Conversion at Late Time | 15 pages, 9 figures | Phys. Rev. D 102, 063018 (2020) | 10.1103/PhysRevD.102.063018 | TIFR/TH/20-15 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study the fully nonlinear fast flavor evolution of neutrinos in 1+1
dimensions. Our numerical analysis shows that at late time the system reaches
an approximately steady state. Using the steady state approximation we
analytically show that the spatial variation of the polarization vectors is
given by their precession around a common axis, which itself has a motion
reminiscent of a gyroscopic pendulum. We then show that the steady state
solution to the equations of motion cannot be separated in position and
velocity, that is the motion is not collective in the usual sense. However, the
fast evolution allows spectral-swap-like dynamics leading to partial
decoherence over a range of velocities, constrained by conservation of lepton
number(s). Finally, we numerically show that at late time the transverse
components of the polarization vectors become randomly oriented at different
spatial locations for any velocity mode and lepton asymmetry.
| [
{
"created": "Fri, 1 May 2020 15:53:28 GMT",
"version": "v1"
},
{
"created": "Mon, 25 May 2020 17:42:14 GMT",
"version": "v2"
}
] | 2020-09-23 | [
[
"Bhattacharyya",
"Soumya",
"",
"TIFR Mumbai"
],
[
"Dasgupta",
"Basudeb",
"",
"TIFR Mumbai"
]
] | We study the fully nonlinear fast flavor evolution of neutrinos in 1+1 dimensions. Our numerical analysis shows that at late time the system reaches an approximately steady state. Using the steady state approximation we analytically show that the spatial variation of the polarization vectors is given by their precession around a common axis, which itself has a motion reminiscent of a gyroscopic pendulum. We then show that the steady state solution to the equations of motion cannot be separated in position and velocity, that is the motion is not collective in the usual sense. However, the fast evolution allows spectral-swap-like dynamics leading to partial decoherence over a range of velocities, constrained by conservation of lepton number(s). Finally, we numerically show that at late time the transverse components of the polarization vectors become randomly oriented at different spatial locations for any velocity mode and lepton asymmetry. |
hep-ph/9503406 | Kazuhiro Tanaka | K. Tanaka (Dept. of Physics, Hiroshima Univ.) | Fermionic excitation in quark matter | 10pages, latex, 3 figures obtainable from author, talk presented at
YITP Workshop on ``From Hadronic Matter to Quark Matter: Evolving View of
Hadronic Matter'', YITP, Kyoto Japan, October (1994). | Prog.Theor.Phys.Suppl.120:177-186,1995 | 10.1143/PTPS.120.177 | HUPD-9511 | hep-ph | null | We discuss the fermionic excitation spectra of the dense QCD and QED plasma
at zero temperature, and analyze the stability of the normal (perturbative)
ground state. The standard re-summed perturbation theory breaks down because
the infrared (IR) divergences show up in the spectra near the Fermi surface. We
employ the effective field theory approach and the renormalization group to
investigate the dynamics near the Fermi surface. Our results indicate that the
dense QCD and QED plasma are non-Fermi-liquids.
| [
{
"created": "Wed, 22 Mar 1995 07:14:14 GMT",
"version": "v1"
}
] | 2008-11-26 | [
[
"Tanaka",
"K.",
"",
"Dept. of Physics, Hiroshima Univ."
]
] | We discuss the fermionic excitation spectra of the dense QCD and QED plasma at zero temperature, and analyze the stability of the normal (perturbative) ground state. The standard re-summed perturbation theory breaks down because the infrared (IR) divergences show up in the spectra near the Fermi surface. We employ the effective field theory approach and the renormalization group to investigate the dynamics near the Fermi surface. Our results indicate that the dense QCD and QED plasma are non-Fermi-liquids. |
hep-ph/9601285 | Ananthanarayan "b." | B. Ananthanarayan and P. B\"uttiker | The Chiral Coupling Constants $\lb{1}$ and $\lb{2}$ from \pipi Phase
Shifts | 36 pages using latex with 1 figure embedded using epsf | Phys.Rev. D54 (1996) 1125-1135 | 10.1103/PhysRevD.54.1125 | BUTP-96/3 | hep-ph | null | A Roy equation analysis of the available $\pi\pi$ phase shift data is
performed with the $I=0$ S- wave scattering length $a^0_0$ in the range
predicted by the one-loop standard chiral perturbation theory. A suitable
dispersive framework is developed to extract the chiral coupling constants
\lb{1}, \lb{2} and yields \lb{1}$=-1.70\pm0.15$ and \lb{2}$\approx 5.0$. We
remark on the implications of this determination to (combinations of) threshold
parameter predictions of the three lowest partial waves.
| [
{
"created": "Wed, 17 Jan 1996 17:41:41 GMT",
"version": "v1"
}
] | 2009-10-28 | [
[
"Ananthanarayan",
"B.",
""
],
[
"Büttiker",
"P.",
""
]
] | A Roy equation analysis of the available $\pi\pi$ phase shift data is performed with the $I=0$ S- wave scattering length $a^0_0$ in the range predicted by the one-loop standard chiral perturbation theory. A suitable dispersive framework is developed to extract the chiral coupling constants \lb{1}, \lb{2} and yields \lb{1}$=-1.70\pm0.15$ and \lb{2}$\approx 5.0$. We remark on the implications of this determination to (combinations of) threshold parameter predictions of the three lowest partial waves. |
hep-ph/0605105 | Yongseok Oh | Yongseok Oh, Hungchong Kim | Scalar kappa meson in K* photoproduction | 9 pages, 4 figures, REVTeX | Phys.Rev.C74:015208,2006 | 10.1103/PhysRevC.74.015208 | null | hep-ph nucl-th | null | We propose that the scalar $\kappa(800)$ meson may play an important role in
$K^*$ photoproduction. In the reactions of $\gamma p \to K^{*+} \Lambda$ and
$\gamma p \to K^{*0} \Sigma^+$, we consider the production mechanisms including
$t$-channel $K^*$, $K$, $\kappa$ exchanges, s-channel $N$, $\Delta$ diagrams,
and $u$-channel $\Lambda$, $\Sigma$, $\Sigma^*$ diagrams within the tree level
approximation, and find that the $\kappa$-meson exchange may contribute
significantly to $K^*\Sigma$ photoproduction, while it is rather supplementary
in $K^*\Lambda$ photoproduction. We demonstrate how the observables of $K^*$
photoproduction can be used to constrain the $\kappa$ meson properties. In
particular, the parity asymmetry can separate the $\kappa$ meson contribution
in $K^*$ photoproduction.
| [
{
"created": "Wed, 10 May 2006 03:29:59 GMT",
"version": "v1"
}
] | 2008-11-26 | [
[
"Oh",
"Yongseok",
""
],
[
"Kim",
"Hungchong",
""
]
] | We propose that the scalar $\kappa(800)$ meson may play an important role in $K^*$ photoproduction. In the reactions of $\gamma p \to K^{*+} \Lambda$ and $\gamma p \to K^{*0} \Sigma^+$, we consider the production mechanisms including $t$-channel $K^*$, $K$, $\kappa$ exchanges, s-channel $N$, $\Delta$ diagrams, and $u$-channel $\Lambda$, $\Sigma$, $\Sigma^*$ diagrams within the tree level approximation, and find that the $\kappa$-meson exchange may contribute significantly to $K^*\Sigma$ photoproduction, while it is rather supplementary in $K^*\Lambda$ photoproduction. We demonstrate how the observables of $K^*$ photoproduction can be used to constrain the $\kappa$ meson properties. In particular, the parity asymmetry can separate the $\kappa$ meson contribution in $K^*$ photoproduction. |
hep-ph/9902394 | Jac Verbaarschot | J.J.M. Verbaarschot | The Infrared Limit of the QCD Dirac Spectrum and Applications oc chiral
Random Matrix Theory to QCD | Lectures given at the APCTP-RCNP Joint International School on
Physics of Hadrons and QCD (Osaka, 1998) and the 1998 YITP-Workshop on QCD
and Hadron Physics (Kyoto, 1998), 58 pages, 7 figures, Latex | null | null | SUNY-NTG-99/2 | hep-ph | null | In the first part of these lectures we discuss the infrared limit of the
spectrum of the QCD Dirac operator. We discuss the global symmetries of the QCD
partition function and show that the Dirac spectrum near zero virtuality is
determined by the pattern of spontaneous chiral symmetry breaking of a QCD-like
partition function with additional bosonic valence quarks and their
super-symmetric partners. We show the existence of an energy scale below which
the fluctuations of the QCD Dirac spectrum are given by a chiral Random Matrix
Theory (chRMT) with the global symmetries of the QCD partition function.
Physically, for valence quark masses below this scale the partition function is
dominated by the zero momentum modes. In the theory of disordered systems, this
energy scale is known as the Thouless energy. In the second part of these
lectures we discuss chRMT as a schematic model for the QCD partition function
at nonzero temperature and chemical potential. We discuss novel features
resulting from the non-Hermiticity of the Dirac operator. The analysis by
Stephanov of the failure of the quenched approximation, the phase diagram of
the chRMT partition function, as well as the properties of Yang-Lee zeros are
discussed. We argue that a localization transition does not occur in the
presence of light quarks. Several results will be derived in full detail. We
mention the flavor symmetries of the QCD Dirac operator for two colors, the
calculation of the valence quark mass dependence of the chiral condensate and
the reduction of the chRMT partition function to the finite volume partition
function.
| [
{
"created": "Thu, 18 Feb 1999 23:11:42 GMT",
"version": "v1"
},
{
"created": "Fri, 26 Feb 1999 20:29:18 GMT",
"version": "v2"
}
] | 2007-05-23 | [
[
"Verbaarschot",
"J. J. M.",
""
]
] | In the first part of these lectures we discuss the infrared limit of the spectrum of the QCD Dirac operator. We discuss the global symmetries of the QCD partition function and show that the Dirac spectrum near zero virtuality is determined by the pattern of spontaneous chiral symmetry breaking of a QCD-like partition function with additional bosonic valence quarks and their super-symmetric partners. We show the existence of an energy scale below which the fluctuations of the QCD Dirac spectrum are given by a chiral Random Matrix Theory (chRMT) with the global symmetries of the QCD partition function. Physically, for valence quark masses below this scale the partition function is dominated by the zero momentum modes. In the theory of disordered systems, this energy scale is known as the Thouless energy. In the second part of these lectures we discuss chRMT as a schematic model for the QCD partition function at nonzero temperature and chemical potential. We discuss novel features resulting from the non-Hermiticity of the Dirac operator. The analysis by Stephanov of the failure of the quenched approximation, the phase diagram of the chRMT partition function, as well as the properties of Yang-Lee zeros are discussed. We argue that a localization transition does not occur in the presence of light quarks. Several results will be derived in full detail. We mention the flavor symmetries of the QCD Dirac operator for two colors, the calculation of the valence quark mass dependence of the chiral condensate and the reduction of the chRMT partition function to the finite volume partition function. |
hep-ph/9503431 | null | A. Datta and M. Guchait (Calcutta) and M. Drees (Madison). | Hunting virtual LSPs at LEP200. | LaTeX with equations.sty; 14 pages with 6 figures (not included).
Entire PS file (including figures) will be available via anonymous ftp from
at ftp://phenom.physics.wisc.edu/pub/preprints/1995 | Z.Phys. C69 (1996) 347-358 | null | MAD-PH-881, DO-TH 94/28. | hep-ph | null | Relatively light sneutrinos, which are experimentally allowed, may
significantly affect the currently popular search strategies for supersymmetric
particles by decaying dominantly into an invisible channel. In certain cases
the second lightest neutralino may also decay invisibly leading to two extra
carriers of missing energy -- in addition to the lightest supersymmetric
particle (LSP) \zi\ -- the virtual LSPs (VLSPs). It is shown that these VLSPs
are allowed in supergravity models with common scalar and gaugino masses at the
unification scale for a sizable region of parameter space and are consistent
with all constraints derived so far from SUSY searches. The pair production of
right handed sleptons, which can very well be the lightest charged SUSY
particles in this scenario, at LEP 200 and their decay signatures are
discussed. The signal survives kinematical cuts required to remove the standard
model background. Charginos are also pair produced copiously if kinematically
accessible; they also decay dominantly into hadronically quiet di--lepton +
\etmiss\ modes leading to interesting unlike sign dilepton events which are
again easily separable from the Standard Model backgrounds at LEP 200 energies.
| [
{
"created": "Fri, 24 Mar 1995 19:01:00 GMT",
"version": "v1"
}
] | 2009-09-25 | [
[
"Datta",
"A.",
"",
"Calcutta"
],
[
"Guchait",
"M.",
"",
"Calcutta"
],
[
"Drees",
"M.",
"",
"Madison"
],
[
".",
"",
""
]
] | Relatively light sneutrinos, which are experimentally allowed, may significantly affect the currently popular search strategies for supersymmetric particles by decaying dominantly into an invisible channel. In certain cases the second lightest neutralino may also decay invisibly leading to two extra carriers of missing energy -- in addition to the lightest supersymmetric particle (LSP) \zi\ -- the virtual LSPs (VLSPs). It is shown that these VLSPs are allowed in supergravity models with common scalar and gaugino masses at the unification scale for a sizable region of parameter space and are consistent with all constraints derived so far from SUSY searches. The pair production of right handed sleptons, which can very well be the lightest charged SUSY particles in this scenario, at LEP 200 and their decay signatures are discussed. The signal survives kinematical cuts required to remove the standard model background. Charginos are also pair produced copiously if kinematically accessible; they also decay dominantly into hadronically quiet di--lepton + \etmiss\ modes leading to interesting unlike sign dilepton events which are again easily separable from the Standard Model backgrounds at LEP 200 energies. |
hep-ph/0106311 | Wim deBoer | W. de Boer, M. Huber, C. Sander (Univ. Karlsruhe), D. I. Kazakov
(JINR, Dubna) | A gobal fit to the anomalous magnetic moment, b->s gamma and Higgs
limits in the constrained MSSM | 12 pages, 7 figs. Refs. updated | null | 10.1016/S0370-2693(01)00895-4 | IEKP-KA/2001-014 | hep-ph | null | New data on the anomalous magnetic moment a_mu of the muon together with the
b->s gamma decay rate are considered within the supergravity inspired
constrained minimal supersymmetric model. We perform a global statistical chi^2
analysis of these data and show that the allowed region of parameter space is
bounded from below by the Higgs limit, which depends on the trilinear coupling
and from above by the anomalous magnetic moment a_mu. The newest b->s gamma
data deviate 1.7 sigma from recent SM calculations and prefer a similar
parameter region as the 2.6 sigma deviation from a_mu.
| [
{
"created": "Wed, 27 Jun 2001 17:15:28 GMT",
"version": "v1"
},
{
"created": "Fri, 29 Jun 2001 17:16:55 GMT",
"version": "v2"
}
] | 2009-11-07 | [
[
"de Boer",
"W.",
"",
"Univ. Karlsruhe"
],
[
"Huber",
"M.",
"",
"Univ. Karlsruhe"
],
[
"Sander",
"C.",
"",
"Univ. Karlsruhe"
],
[
"Kazakov",
"D. I.",
"",
"JINR, Dubna"
]
] | New data on the anomalous magnetic moment a_mu of the muon together with the b->s gamma decay rate are considered within the supergravity inspired constrained minimal supersymmetric model. We perform a global statistical chi^2 analysis of these data and show that the allowed region of parameter space is bounded from below by the Higgs limit, which depends on the trilinear coupling and from above by the anomalous magnetic moment a_mu. The newest b->s gamma data deviate 1.7 sigma from recent SM calculations and prefer a similar parameter region as the 2.6 sigma deviation from a_mu. |
1308.1112 | David Latimer | David C. Latimer | Dispersive Light Propagation at Cosmological Distances: Matter Effects | version to appear in Phys. Rev. D | null | 10.1103/PhysRevD.88.063517 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Searches for dispersive effects in the propagation of light at cosmological
distances have been touted as sensitive probes of Lorentz invariance violation
(LIV) and of theories of quantum gravity. Frequency-dependent time lags between
simultaneously emitted pulses of light can signal a modification in the photon
dispersion relation; however, matter engenders the cosmos with a dispersive
index of refraction to similar effect. We construct a theoretical framework for
the analysis of such effects, contrasting these dispersive terms with those
from LIV models. We consider all matter, both luminous and dark. Though the
only known mode of interaction for dark matter (DM) is gravitational, most
models of dark matter also allow for electromagnetic interactions, if only at
the one-loop level in perturbation theory. Generically, the leading order
dispersive effects due to matter scale with photon energy as \omega^{-2} for a
charged DM candidate and \omega^2 for a neutral DM candidate. Terms linear in
\omega can arise in the index of refraction if parity and charge-parity
asymmetries are present at the Lagrangian or system level. Herein, we compute
the index of refraction for a millicharged dark matter candidate at the
one-loop level, a neutral scalar DM candidate introduced by Boehm and Fayet,
and the MSSM's neutralino. For a neutral DM candidate, we determine that matter
effects can compete with LIV effects that depend quadratically on energy
whenever the photon energy is beyond 10^{29} GeV, well beyond the GZK cutoff.
The dispersive matter effects that scale linearly with \omega are model
dependent, and their existence results in circular birefringence.
| [
{
"created": "Mon, 5 Aug 2013 20:37:55 GMT",
"version": "v1"
},
{
"created": "Fri, 6 Sep 2013 02:38:39 GMT",
"version": "v2"
}
] | 2013-09-18 | [
[
"Latimer",
"David C.",
""
]
] | Searches for dispersive effects in the propagation of light at cosmological distances have been touted as sensitive probes of Lorentz invariance violation (LIV) and of theories of quantum gravity. Frequency-dependent time lags between simultaneously emitted pulses of light can signal a modification in the photon dispersion relation; however, matter engenders the cosmos with a dispersive index of refraction to similar effect. We construct a theoretical framework for the analysis of such effects, contrasting these dispersive terms with those from LIV models. We consider all matter, both luminous and dark. Though the only known mode of interaction for dark matter (DM) is gravitational, most models of dark matter also allow for electromagnetic interactions, if only at the one-loop level in perturbation theory. Generically, the leading order dispersive effects due to matter scale with photon energy as \omega^{-2} for a charged DM candidate and \omega^2 for a neutral DM candidate. Terms linear in \omega can arise in the index of refraction if parity and charge-parity asymmetries are present at the Lagrangian or system level. Herein, we compute the index of refraction for a millicharged dark matter candidate at the one-loop level, a neutral scalar DM candidate introduced by Boehm and Fayet, and the MSSM's neutralino. For a neutral DM candidate, we determine that matter effects can compete with LIV effects that depend quadratically on energy whenever the photon energy is beyond 10^{29} GeV, well beyond the GZK cutoff. The dispersive matter effects that scale linearly with \omega are model dependent, and their existence results in circular birefringence. |
1801.02906 | Peter Filip | Peter Filip | Magnetic Polarizability of Virtual (ss') and (cc') Pairs in the Nucleon | 4 pages, 1 figure, prepared for DSPIN 2017 conference proceedings | Journal of Physics: Conference Series 938 (2017) 012045 | 10.1088/1742-6596/938/1/012045 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We suggest 3P0 quantum state of virtual (ss') pairs in the nucleon can be
polarised by the internal fields permeating the volume of the nucleon (proton
or neutron). Due to the quadratic Zeeman interaction, 3P0 wavefunction of
virtual (qq') pairs acquires the admixture of 1P10 quantum state in the
magnetic field, which generates the antiparallel polarization of s and s'
quarks (in the nucleon). Considering the internal magnetic fields of neutron
and proton (originating from their measured magnetic dipole moments), we
suggest the induced s-quark polarization in the neutron to be of the oposite
direction compared to the proton case. We mention the influence of the internal
chromo-magnetic fields on the quantum state of (qq') pairs in the nucleon and
we discuss also the expected behaviour of virtual (cc') pairs.
| [
{
"created": "Tue, 9 Jan 2018 12:14:02 GMT",
"version": "v1"
}
] | 2018-01-10 | [
[
"Filip",
"Peter",
""
]
] | We suggest 3P0 quantum state of virtual (ss') pairs in the nucleon can be polarised by the internal fields permeating the volume of the nucleon (proton or neutron). Due to the quadratic Zeeman interaction, 3P0 wavefunction of virtual (qq') pairs acquires the admixture of 1P10 quantum state in the magnetic field, which generates the antiparallel polarization of s and s' quarks (in the nucleon). Considering the internal magnetic fields of neutron and proton (originating from their measured magnetic dipole moments), we suggest the induced s-quark polarization in the neutron to be of the oposite direction compared to the proton case. We mention the influence of the internal chromo-magnetic fields on the quantum state of (qq') pairs in the nucleon and we discuss also the expected behaviour of virtual (cc') pairs. |
hep-ph/0003018 | Lev Kofman | Patrick B. Greene (Toronto U.), Lev Kofman (CITA) | On the Theory of Fermionic Preheating | 14 pages, latex, 12 figures, submitted for publication | Phys.Rev. D62 (2000) 123516 | 10.1103/PhysRevD.62.123516 | CITA-2000-05 | hep-ph | null | In inflationary cosmology, the particles constituting the Universe are
created after inflation due to their interaction with moving inflaton field(s)
in the process of preheating. In the fermionic sector, the leading channel is
out-of equilibrium particle production in the non-perturbative regime of
parametric excitation, which respects Pauli blocking but differs significantly
from the perturbative expectation. We develop theory of fermionic preheating
coupling to the inflaton, without and with expansion of the universe, for light
and massive fermions, to calculate analytically the occupation number of
created fermions, focusing on their spectra and time evolution. In the case of
large resonant parameter $q$ we extend for rermions the method of successive
parabolic scattering, earlier developed for bosonic preheating. In an expanding
universe parametric excitation of fermions is stochastic. Created fermions very
quickly, within tens of inflaton oscillations, fill up a sphere of radius
$\simeq q^{1/4}$ in monetum space. We extend our formalism to the production of
superheavy fermions and to `instant' fermion creation.
| [
{
"created": "Fri, 3 Mar 2000 23:49:33 GMT",
"version": "v1"
}
] | 2009-10-31 | [
[
"Greene",
"Patrick B.",
"",
"Toronto U."
],
[
"Kofman",
"Lev",
"",
"CITA"
]
] | In inflationary cosmology, the particles constituting the Universe are created after inflation due to their interaction with moving inflaton field(s) in the process of preheating. In the fermionic sector, the leading channel is out-of equilibrium particle production in the non-perturbative regime of parametric excitation, which respects Pauli blocking but differs significantly from the perturbative expectation. We develop theory of fermionic preheating coupling to the inflaton, without and with expansion of the universe, for light and massive fermions, to calculate analytically the occupation number of created fermions, focusing on their spectra and time evolution. In the case of large resonant parameter $q$ we extend for rermions the method of successive parabolic scattering, earlier developed for bosonic preheating. In an expanding universe parametric excitation of fermions is stochastic. Created fermions very quickly, within tens of inflaton oscillations, fill up a sphere of radius $\simeq q^{1/4}$ in monetum space. We extend our formalism to the production of superheavy fermions and to `instant' fermion creation. |
hep-ph/0207345 | Igor Ivanov | I.F. Ginzburg (1), I.P. Ivanov (1 and 2), N.N. Nikolaev (2 and 3) ((1)
Sobolev Institute of Mathematics, Novosibirsk, Russia, (2) IKP,
Forschungszentrum Juelich, Germany, (3) Landau ITP, Moscow, Russia) | Possibility of the odderon discovery via observation of charge asymmetry
in the diffractive pi+pi- production at HERA | LaTeX, 16 pages, 2 figures, expanded discussion, changes to abstract,
slight correction of the title | Eur.Phys.J.direct C5:02,2003; Eur.Phys.J.direct C30:002,2003 | null | FZJ-IKP(Th)-2002/15 | hep-ph hep-ex | null | The interference between the Pomeron and possible odderon mechanisms of
diffractive pi+pi- photoproduction results in charge asymmetry of the produced
pions. The observation of charge asymmetry of pions at moderate M_{pi+pi-} will
be an undoubted signal of odderon existence. To make numeral estimates more
definite, we limit ourselves by the region M_{pi+pi-} = 1.1 -- 1.5 GeV, where
in the odderon mechanism of dipion production, the production via single
f_2(1270) resonance is expected to be dominant. We find a very statistically
significant effect of the odderon induced charge asymmetry even with very
modest estimates for the f_2 photoproduction cross section (without referring
to any particular model of the odderon).
| [
{
"created": "Mon, 29 Jul 2002 16:39:26 GMT",
"version": "v1"
},
{
"created": "Mon, 3 Feb 2003 15:37:00 GMT",
"version": "v2"
}
] | 2014-11-17 | [
[
"Ginzburg",
"I. F.",
"",
"1 and 2"
],
[
"Ivanov",
"I. P.",
"",
"1 and 2"
],
[
"Nikolaev",
"N. N.",
"",
"2 and 3"
]
] | The interference between the Pomeron and possible odderon mechanisms of diffractive pi+pi- photoproduction results in charge asymmetry of the produced pions. The observation of charge asymmetry of pions at moderate M_{pi+pi-} will be an undoubted signal of odderon existence. To make numeral estimates more definite, we limit ourselves by the region M_{pi+pi-} = 1.1 -- 1.5 GeV, where in the odderon mechanism of dipion production, the production via single f_2(1270) resonance is expected to be dominant. We find a very statistically significant effect of the odderon induced charge asymmetry even with very modest estimates for the f_2 photoproduction cross section (without referring to any particular model of the odderon). |
1810.11872 | Nelson R. F. Braga | Nelson R. F. Braga and Luiz F. Ferreira | Quasinormal modes and dispersion relations for quarkonium in a plasma | V2: enlarged version with clarifications, more comparison with
previous articles and additional references included. 11 figures, 2 tables,
62 references. Version accepted for publication in JHEP | null | 10.1007/JHEP01(2019)082 | null | hep-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Recent investigations show that the thermal spectral function of heavy $ {b
\bar b } $ and $ {c \bar c} $ vector mesons can be described using holography.
These studies consider a bottom up model that captures the heavy flavour
spectroscopy of masses and decay constants in the vacuum and is consistently
extended to finite temperature. The corresponding spectral functions provide a
picture of the dissociation process in terms of the decrease of the quasi-state
peaks with temperature.
Another related tool that provides important information about the thermal
behaviour is the analysis of the quasinormal modes. They are field solutions in
a curved background assumed to represent, in gauge/gravity duality,
quasi-particle states in a thermal medium. The associated complex frequencies
are related to the thermal mass and width. We present here the calculation of
quasinormal modes for charmonium and bottomonium using the holographic
approach. The temperature dependence of mass and thermal width are
investigated. Solutions corresponding to heavy mesons moving into the plasma
are also studied. They provide the dependence of the real and imaginary parts
of the frequency with the quasi-particle momenta, the so called dispersion
relations.
| [
{
"created": "Sun, 28 Oct 2018 19:59:06 GMT",
"version": "v1"
},
{
"created": "Sat, 5 Jan 2019 18:45:46 GMT",
"version": "v2"
}
] | 2019-01-30 | [
[
"Braga",
"Nelson R. F.",
""
],
[
"Ferreira",
"Luiz F.",
""
]
] | Recent investigations show that the thermal spectral function of heavy $ {b \bar b } $ and $ {c \bar c} $ vector mesons can be described using holography. These studies consider a bottom up model that captures the heavy flavour spectroscopy of masses and decay constants in the vacuum and is consistently extended to finite temperature. The corresponding spectral functions provide a picture of the dissociation process in terms of the decrease of the quasi-state peaks with temperature. Another related tool that provides important information about the thermal behaviour is the analysis of the quasinormal modes. They are field solutions in a curved background assumed to represent, in gauge/gravity duality, quasi-particle states in a thermal medium. The associated complex frequencies are related to the thermal mass and width. We present here the calculation of quasinormal modes for charmonium and bottomonium using the holographic approach. The temperature dependence of mass and thermal width are investigated. Solutions corresponding to heavy mesons moving into the plasma are also studied. They provide the dependence of the real and imaginary parts of the frequency with the quasi-particle momenta, the so called dispersion relations. |
0712.3300 | Ryuichiro Kitano | Masahiro Ibe, Ryuichiro Kitano | Supersymmetric Model Building (and Sweet Spot Supersymmetry) | Based on lectures given at Summer Institute 2007, Fuji-Yoshida,
Japan, Aug. 3-10, 2007. 13 pages, 4 figures, 1 table | null | null | LA-UR-07-7938, SLAC-PUB-13059 | hep-ph | null | It has been more than twenty years since theorists started discussing
supersymmetric model building/phenomenology. We review mechanisms of
supersymmetry breaking/mediation and problems in each scenario. We propose a
simple model to address those problems and discuss its phenomenology.
| [
{
"created": "Wed, 19 Dec 2007 22:18:14 GMT",
"version": "v1"
}
] | 2007-12-21 | [
[
"Ibe",
"Masahiro",
""
],
[
"Kitano",
"Ryuichiro",
""
]
] | It has been more than twenty years since theorists started discussing supersymmetric model building/phenomenology. We review mechanisms of supersymmetry breaking/mediation and problems in each scenario. We propose a simple model to address those problems and discuss its phenomenology. |
1907.05616 | Giancarlo D'Ambrosio | Giancarlo D'Ambrosio | Theory perspectives on rare Kaon decays and CPV | FPCP 2019 proceedings. 4 pages, 5 figures | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The following proceedings contain a theory perspective on rare Kaon decays. I
review rare kaon decays in the LHC era: we discuss interplay with B-anomalies
and possible New Physics in direct CP violation in $K\to 2\pi$: very rare kaon
decays like $K \to \pi \nu \bar{\nu}$ are very important to this purpose. We
discuss also the decays $K^0 \to \mu ^+ \mu ^-$ due to the LHCB measurement
| [
{
"created": "Fri, 12 Jul 2019 08:28:24 GMT",
"version": "v1"
}
] | 2019-07-15 | [
[
"D'Ambrosio",
"Giancarlo",
""
]
] | The following proceedings contain a theory perspective on rare Kaon decays. I review rare kaon decays in the LHC era: we discuss interplay with B-anomalies and possible New Physics in direct CP violation in $K\to 2\pi$: very rare kaon decays like $K \to \pi \nu \bar{\nu}$ are very important to this purpose. We discuss also the decays $K^0 \to \mu ^+ \mu ^-$ due to the LHCB measurement |
hep-ph/0408007 | Makiko Nagashima | Wei-Shu Hou and Makiko Nagashima | Resolving the B-> phi K^* Polarization Anomaly | 4 pages, 9 figures, minor updates, slight changes of numerics for
figures, more acknowledgements | null | null | null | hep-ph | null | The experimental observation of sizable transverse components for B-> phi K^*
decay is in strong contrast to all other VV modes, and poses a challenge to our
understanding of B decay dynamics. Observing that the gluon emitted from b->
sg^{(*)} chromodipole transition is transverse, we give a heuristic model where
the transverse phi descends from the emitted gluon, hence similar phenomena
should occur for B-> omega K^* but not for B-> rho^0 K^*. New physics in bsg
chromodipole coupling, perhaps needed for the \bar B -> phi K_S CP violation
anomaly, may lead to different patterns of CP and T violation in transverse
components of \bar B -> phi \bar K^*, omega \bar K^* decays.
| [
{
"created": "Sun, 1 Aug 2004 15:14:11 GMT",
"version": "v1"
},
{
"created": "Fri, 13 Aug 2004 07:14:10 GMT",
"version": "v2"
}
] | 2007-05-23 | [
[
"Hou",
"Wei-Shu",
""
],
[
"Nagashima",
"Makiko",
""
]
] | The experimental observation of sizable transverse components for B-> phi K^* decay is in strong contrast to all other VV modes, and poses a challenge to our understanding of B decay dynamics. Observing that the gluon emitted from b-> sg^{(*)} chromodipole transition is transverse, we give a heuristic model where the transverse phi descends from the emitted gluon, hence similar phenomena should occur for B-> omega K^* but not for B-> rho^0 K^*. New physics in bsg chromodipole coupling, perhaps needed for the \bar B -> phi K_S CP violation anomaly, may lead to different patterns of CP and T violation in transverse components of \bar B -> phi \bar K^*, omega \bar K^* decays. |
0707.0381 | Ansgar Denner | M. Ciccolini, A. Denner, S. Dittmaier | Strong and electroweak corrections to the production of Higgs+2jets via
weak interactions at the LHC | 5 pages, LaTeX, 5 postscript figures | Phys.Rev.Lett.99:161803,2007 | 10.1103/PhysRevLett.99.161803 | MPP-2007-82, PSI-PR-07-03 | hep-ph | null | Radiative corrections of strong and electroweak interactions are presented at
next-to-leading order for the production of a Higgs boson plus two hard jets
via weak interactions at the LHC. The calculation includes all weak-boson
fusion and quark-antiquark annihilation diagrams as well as the corresponding
interferences. The electroweak corrections, which are discussed here for the
first time, reduce the cross sections by 5%, and thus are of the same order of
magnitude as the QCD corrections. As argued in previous papers, where s-channel
diagrams and interferences were neglected, the QCD corrections connected to
interference effects are small.
| [
{
"created": "Tue, 3 Jul 2007 10:49:36 GMT",
"version": "v1"
}
] | 2008-11-26 | [
[
"Ciccolini",
"M.",
""
],
[
"Denner",
"A.",
""
],
[
"Dittmaier",
"S.",
""
]
] | Radiative corrections of strong and electroweak interactions are presented at next-to-leading order for the production of a Higgs boson plus two hard jets via weak interactions at the LHC. The calculation includes all weak-boson fusion and quark-antiquark annihilation diagrams as well as the corresponding interferences. The electroweak corrections, which are discussed here for the first time, reduce the cross sections by 5%, and thus are of the same order of magnitude as the QCD corrections. As argued in previous papers, where s-channel diagrams and interferences were neglected, the QCD corrections connected to interference effects are small. |
0901.1647 | Raphael Granier de Cassagnac | R. Granier de Cassagnac | Cold nuclear effects on heavy flavours (a review) | 8 pages, 6x2 figures, SQM08 proceedings, version accepted by
J.Phys.G. Figure 4 left and 5 right remade | J.Phys.G36:064024,2009 | 10.1088/0954-3899/36/6/064024 | null | hep-ph nucl-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Before wondering about the quark-gluon plasma (QGP), one has to take into
account various cold (normal) nuclear matter effects, that can be probed
through p+A like collisions. This article aims at reviewing the current results
(and understanding) of these effects on heavy quarks and quarkonia production.
| [
{
"created": "Mon, 12 Jan 2009 19:46:57 GMT",
"version": "v1"
},
{
"created": "Sun, 8 Mar 2009 13:51:16 GMT",
"version": "v2"
}
] | 2010-01-15 | [
[
"de Cassagnac",
"R. Granier",
""
]
] | Before wondering about the quark-gluon plasma (QGP), one has to take into account various cold (normal) nuclear matter effects, that can be probed through p+A like collisions. This article aims at reviewing the current results (and understanding) of these effects on heavy quarks and quarkonia production. |
0909.0381 | Cecilia Tarantino | Cecilia Tarantino | FCNC Processes in the LHT Model: a 2009 Look | 3 pages, Proceedings of the 2009 Europhysics Conference on High
Energy Physics, July 2009, Krakow | PoS EPS-HEP2009 2009:185,2009 | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present a summary of our recent analysis update of flavour changing
neutral current (FCNC) processes in the Littlest Higgs model with T-parity
(LHT). The essential novelties of our update are: the removal of the
logarithmic UV cutoff dependence by the inclusion of the new contribution to
the Z^0-penguin diagrams identified by Goto et al. and by del Aguila et al.,
the study of the decay K_L -> mu^+ mu^-, a discussion of fine-tuning in
epsilon_K and Br(mu -> e gamma).
| [
{
"created": "Wed, 2 Sep 2009 10:45:05 GMT",
"version": "v1"
}
] | 2014-11-20 | [
[
"Tarantino",
"Cecilia",
""
]
] | We present a summary of our recent analysis update of flavour changing neutral current (FCNC) processes in the Littlest Higgs model with T-parity (LHT). The essential novelties of our update are: the removal of the logarithmic UV cutoff dependence by the inclusion of the new contribution to the Z^0-penguin diagrams identified by Goto et al. and by del Aguila et al., the study of the decay K_L -> mu^+ mu^-, a discussion of fine-tuning in epsilon_K and Br(mu -> e gamma). |
1604.03598 | Martin Wolfgang Winkler | Hans Peter Nilles, Martin Wolfgang Winkler | 750 GeV Diphotons and Supersymmetric Grand Unification | 20 pages, 6 figures | null | 10.1007/JHEP05(2016)182 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We investigate the 750 GeV diphoton excess in terms of supersymmetric models
which preserve grand unification in the ultraviolet. We show that minimal
extensions of the MSSM by a singlet and a vector-like 5-plet or 10-plet of
SU(5) can explain the observed signal while remaining perturbative up to the
GUT scale. Different from previous analyses we rely on light sfermions in the
loops which - compared to the analog non-supersymmetric models - enhance the
diphoton cross section by up to a factor of seven. While the resonance decay
width is narrow, mass splitting of the scalar and pseudoscalar components may
result in a double resonance. We perform a likelihood analysis on the ATLAS and
CMS data to show that the significance of the diphoton excess increases from
3.3 sigma (single narrow resonance) to 3.9 sigma for the double resonance. We
also provide signal predictions in other diboson channels to be tested at
LHC-13.
| [
{
"created": "Tue, 12 Apr 2016 21:57:58 GMT",
"version": "v1"
}
] | 2016-06-29 | [
[
"Nilles",
"Hans Peter",
""
],
[
"Winkler",
"Martin Wolfgang",
""
]
] | We investigate the 750 GeV diphoton excess in terms of supersymmetric models which preserve grand unification in the ultraviolet. We show that minimal extensions of the MSSM by a singlet and a vector-like 5-plet or 10-plet of SU(5) can explain the observed signal while remaining perturbative up to the GUT scale. Different from previous analyses we rely on light sfermions in the loops which - compared to the analog non-supersymmetric models - enhance the diphoton cross section by up to a factor of seven. While the resonance decay width is narrow, mass splitting of the scalar and pseudoscalar components may result in a double resonance. We perform a likelihood analysis on the ATLAS and CMS data to show that the significance of the diphoton excess increases from 3.3 sigma (single narrow resonance) to 3.9 sigma for the double resonance. We also provide signal predictions in other diboson channels to be tested at LHC-13. |
hep-ph/0408125 | Naveen Gaur | S. Rai Choudhury, Naveen Gaur, G.C.Joshi and B.H.J.McKellar | $K_L \to \pi^0 \nu \bar{\nu}$ in Little Higgs model | formatting changed, some typos in expressions corrected, some
references added | null | null | null | hep-ph | null | Little Higgs models provides us a new solution of the {\it hierarchy problem}
of the SM. The problem is associated with the large difference in scales of SM
and plank scale. One of the main features of these models is the existence of a
vector like top quark. The CP violating $K_L \to \pi^0 \nu \bar{\nu}$ process n
the SM model is dominated by top quark penguin & box graphs. We examine this
process in the Little Higgs model where the top quark sector has significant
differences from the Standard Model.
| [
{
"created": "Tue, 10 Aug 2004 08:25:55 GMT",
"version": "v1"
},
{
"created": "Wed, 26 Jan 2005 07:49:09 GMT",
"version": "v2"
}
] | 2007-05-23 | [
[
"Choudhury",
"S. Rai",
""
],
[
"Gaur",
"Naveen",
""
],
[
"Joshi",
"G. C.",
""
],
[
"McKellar",
"B. H. J.",
""
]
] | Little Higgs models provides us a new solution of the {\it hierarchy problem} of the SM. The problem is associated with the large difference in scales of SM and plank scale. One of the main features of these models is the existence of a vector like top quark. The CP violating $K_L \to \pi^0 \nu \bar{\nu}$ process n the SM model is dominated by top quark penguin & box graphs. We examine this process in the Little Higgs model where the top quark sector has significant differences from the Standard Model. |
hep-ph/9611408 | null | A. Giovannini (Univ. Torino and INFN) | Clan concept in multiparticle dynamics and the NB ``enigma'' | LaTeX, 11 pages, uses sprocl.sty, to appear in the Proc. of the XXVI
INternational Symposium on Multiparticle Dynamics, Faro, Portugal, September
1st-5th, 1996 | null | null | DFTT 70-96 | hep-ph | null | A summary of main results on NB (Negative Binomial) regularity and related
clan concept since their first appearance in multiparticle dynamics is
presented.
| [
{
"created": "Mon, 25 Nov 1996 11:16:37 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Giovannini",
"A.",
"",
"Univ. Torino and INFN"
]
] | A summary of main results on NB (Negative Binomial) regularity and related clan concept since their first appearance in multiparticle dynamics is presented. |
1110.3688 | Elizabeth H. Simmons | R. Sekhar Chivukula, Pawin Ittisamai, Jing Ren, and Elizabeth H.
Simmons | Technipion Limits from LHC Higgs Searches | 15 pages, 5 figures, PDF-LaTeX | Phys.Rev. D84 (2011) 115025; (Erratum) Phys.Rev. D85 (2012) 119903 | 10.1103/PhysRevD.84.115025 | MSUHEP-111013 | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | LHC searches for the standard model Higgs Boson in di-photon or di-tau decay
modes place strong constraints on the light top-pion state predicted in
technicolor models that include colored technifermions. Compared with the
standard Higgs Boson, the top-pions have an enhanced production rate (largely
because the technipion decay constant is smaller than the weak scale) and also
enhanced branching ratios into di-photon and di-tau final states (largely due
to the suppression of WW decays of the technipions). These factors combine to
make the technipions more visible in both channels than a standard model Higgs
would be. Hence, the recent ATLAS and CMS searches for Higgs bosons exclude the
presence of technipions with masses from 110 GeV to nearly twice the top-quark
mass in technicolor models that (a) include colored technifermions (b) feature
topcolor dynamics and (c) have technicolor groups with three or more
technicolors. For certain models, the limits also apply out to higher
technipion masses or down to the minimum number of technicolors. The limits may
be softened somewhat in models where extended technicolor plays a significant
role in producing the top quark's mass. Additional LHC data on di-tau and
di-photon final states will be extremely valuable in further exploring
technicolor parameter space.
| [
{
"created": "Mon, 17 Oct 2011 15:00:38 GMT",
"version": "v1"
}
] | 2016-11-25 | [
[
"Chivukula",
"R. Sekhar",
""
],
[
"Ittisamai",
"Pawin",
""
],
[
"Ren",
"Jing",
""
],
[
"Simmons",
"Elizabeth H.",
""
]
] | LHC searches for the standard model Higgs Boson in di-photon or di-tau decay modes place strong constraints on the light top-pion state predicted in technicolor models that include colored technifermions. Compared with the standard Higgs Boson, the top-pions have an enhanced production rate (largely because the technipion decay constant is smaller than the weak scale) and also enhanced branching ratios into di-photon and di-tau final states (largely due to the suppression of WW decays of the technipions). These factors combine to make the technipions more visible in both channels than a standard model Higgs would be. Hence, the recent ATLAS and CMS searches for Higgs bosons exclude the presence of technipions with masses from 110 GeV to nearly twice the top-quark mass in technicolor models that (a) include colored technifermions (b) feature topcolor dynamics and (c) have technicolor groups with three or more technicolors. For certain models, the limits also apply out to higher technipion masses or down to the minimum number of technicolors. The limits may be softened somewhat in models where extended technicolor plays a significant role in producing the top quark's mass. Additional LHC data on di-tau and di-photon final states will be extremely valuable in further exploring technicolor parameter space. |
0809.4934 | Simone Marzani | Simone Marzani, Richard D. Ball, Vittorio Del Duca, Stefano Forte,
Alessandro Vicini | Finite-top-mass effects in NNLO Higgs production | 4 pages, 4 figures; to be published in the proceedings of QCD2008.
Reference added | Nuclear Physics B 186C (Proceedings Supplements) (2009) pp. 98-101 | 10.1016/j.nuclphysbps.2008.12.019 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We construct an accurate approximation to the exact NNLO cross section for
Higgs production in gluon-gluon fusion by matching the dominant finite top mass
corrections recently computed by us to the known result in the infinite mass
limit. The ensuing corrections to the partonic cross section are very large
when the center of mass energy of the partonic collision is much larger than
the Higgs mass, but lead to a moderate correction at the percent level to the
total Higgs production cross section at the LHC. Our computation thus reduces
the uncertainty related to these corrections at the LHC from the percent to the
per mille level.
| [
{
"created": "Mon, 29 Sep 2008 11:16:24 GMT",
"version": "v1"
},
{
"created": "Tue, 30 Sep 2008 17:08:34 GMT",
"version": "v2"
}
] | 2009-02-24 | [
[
"Marzani",
"Simone",
""
],
[
"Ball",
"Richard D.",
""
],
[
"Del Duca",
"Vittorio",
""
],
[
"Forte",
"Stefano",
""
],
[
"Vicini",
"Alessandro",
""
]
] | We construct an accurate approximation to the exact NNLO cross section for Higgs production in gluon-gluon fusion by matching the dominant finite top mass corrections recently computed by us to the known result in the infinite mass limit. The ensuing corrections to the partonic cross section are very large when the center of mass energy of the partonic collision is much larger than the Higgs mass, but lead to a moderate correction at the percent level to the total Higgs production cross section at the LHC. Our computation thus reduces the uncertainty related to these corrections at the LHC from the percent to the per mille level. |
hep-ph/9508248 | Elena Balandina | E.V.Balandina, A.F.Krutov and V.E.Troitsky | Elastic Charge Form Factors of $\pi$ and K Mesons | 9 pages, LaTeX, 2 uuencoded PostScript figures | J.Phys.G22:1585-1592,1996 | 10.1088/0954-3899/22/11/006 | 95-27/391 | hep-ph | null | The elastic charge form factors of the charged $\pi$ and $K$ mesons are
calculated in modified impulse approximation using instant form of relativistic
Hamiltonian dynamics. Our approach gives pion and kaon electromagnetic form
factors in the large range of momentum transfer. The results are in good
agreement with the available data. Relativistic effects are large at all values
of momentum transfers. The pion and kaon form factors at large $Q^2$ depend
strongly on the choice of model. The experiments on pion form factor at large
momentum transfer planned at CEBAF will choose between such models. In the case
of kaon such a choosing may be performed only if supplemented by accurate
measurements of kaon MSR.
| [
{
"created": "Mon, 7 Aug 1995 14:09:43 GMT",
"version": "v1"
}
] | 2008-11-26 | [
[
"Balandina",
"E. V.",
""
],
[
"Krutov",
"A. F.",
""
],
[
"Troitsky",
"V. E.",
""
]
] | The elastic charge form factors of the charged $\pi$ and $K$ mesons are calculated in modified impulse approximation using instant form of relativistic Hamiltonian dynamics. Our approach gives pion and kaon electromagnetic form factors in the large range of momentum transfer. The results are in good agreement with the available data. Relativistic effects are large at all values of momentum transfers. The pion and kaon form factors at large $Q^2$ depend strongly on the choice of model. The experiments on pion form factor at large momentum transfer planned at CEBAF will choose between such models. In the case of kaon such a choosing may be performed only if supplemented by accurate measurements of kaon MSR. |
hep-ph/9905495 | Arnd Brandenburg | A. Brandenburg, P.N. Burrows, D. Muller, N. Oishi, P. Uwer | Measurement of the running b-quark mass using $e^+e^- \to b\bar{b}g$
events | 22 pages (LaTeX), 1 Postscript figure. Version to appear in Phys.
Lett. B. Several clarifying remarks added in the text, typos corrected, and
theoretical results for very small masses added in the figure | Phys.Lett.B468:168-177,1999 | 10.1016/S0370-2693(99)01194-6 | SLAC-PUB-7915, OUNP-99-06, Saclay/SPhT-T99/047, PITHA 99/12 | hep-ph hep-ex | null | We have studied the determination of the running b-quark mass, $m_b(M_Z)$,
using $Z^0$ decays into 3 or more hadronic jets. We calculated the ratio of
$\geq3$-jet fractions in $e^+e^-\to b\bar{b}$ vs. $e^+e^-\to q_l\bar{q_l}$
($q_l$ = u or d or s) events at next-to-leading order in perturbative QCD using
six different infra-red- and collinear-safe jet-finding algorithms. We compared
with corresponding measurements from the SLD Collaboration and found a
significant algorithm-dependence of the fitted $m_b(M_Z)$ value. Our best
estimate, taking correlations into account, is $m_b(M_Z) = 2.56 \pm 0.27
(stat.) ^{+0.28}_{-0.38} (syst.) ^{+0.49}_{-1.48} (theor.) GeV/c^2$.
| [
{
"created": "Wed, 26 May 1999 15:26:53 GMT",
"version": "v1"
},
{
"created": "Mon, 20 Sep 1999 12:46:36 GMT",
"version": "v2"
}
] | 2008-11-26 | [
[
"Brandenburg",
"A.",
""
],
[
"Burrows",
"P. N.",
""
],
[
"Muller",
"D.",
""
],
[
"Oishi",
"N.",
""
],
[
"Uwer",
"P.",
""
]
] | We have studied the determination of the running b-quark mass, $m_b(M_Z)$, using $Z^0$ decays into 3 or more hadronic jets. We calculated the ratio of $\geq3$-jet fractions in $e^+e^-\to b\bar{b}$ vs. $e^+e^-\to q_l\bar{q_l}$ ($q_l$ = u or d or s) events at next-to-leading order in perturbative QCD using six different infra-red- and collinear-safe jet-finding algorithms. We compared with corresponding measurements from the SLD Collaboration and found a significant algorithm-dependence of the fitted $m_b(M_Z)$ value. Our best estimate, taking correlations into account, is $m_b(M_Z) = 2.56 \pm 0.27 (stat.) ^{+0.28}_{-0.38} (syst.) ^{+0.49}_{-1.48} (theor.) GeV/c^2$. |
1309.7300 | Antoni Szczurek | Piotr Lebiedowicz, Roman Pasechnik and Antoni Szczurek | Search for technipions in exclusive production of diphotons with large
invariant masses at the LHC | 20 pages, 12 figures, 1 table | null | 10.1016/j.nuclphysb.2014.02.008 | null | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We focus on exclusive production of neutral technipion $\tilde \pi^0$ in $pp$
collisions at the LHC, i.e. on $p p \to p p \tilde \pi^0$ reaction. The
dependence of the cross section on parameters of recently proposed vector-like
Technicolor model is studied. Characteristic features of the differential
distributions are discussed. For not too large technipion masses the diphoton
decay channel has the dominant branching fraction. This is also the main reason
for an enhanced production of neutral technipions in $\gamma\gamma$-fusion
reaction. We discuss potential backgrounds of the QCD and QED origin to the $p
p \to p p (\tilde{\pi}^0 \to \gamma \gamma)$ process at large invariant
$\gamma\gamma$ masses. We conclude that compared to inclusive case the
signal-to-background ratio in the considered exclusive reaction is vary
favorable which thereby could serve as a good probe for Technicolor dynamics
searches at the LHC.
| [
{
"created": "Fri, 27 Sep 2013 17:12:29 GMT",
"version": "v1"
}
] | 2015-06-17 | [
[
"Lebiedowicz",
"Piotr",
""
],
[
"Pasechnik",
"Roman",
""
],
[
"Szczurek",
"Antoni",
""
]
] | We focus on exclusive production of neutral technipion $\tilde \pi^0$ in $pp$ collisions at the LHC, i.e. on $p p \to p p \tilde \pi^0$ reaction. The dependence of the cross section on parameters of recently proposed vector-like Technicolor model is studied. Characteristic features of the differential distributions are discussed. For not too large technipion masses the diphoton decay channel has the dominant branching fraction. This is also the main reason for an enhanced production of neutral technipions in $\gamma\gamma$-fusion reaction. We discuss potential backgrounds of the QCD and QED origin to the $p p \to p p (\tilde{\pi}^0 \to \gamma \gamma)$ process at large invariant $\gamma\gamma$ masses. We conclude that compared to inclusive case the signal-to-background ratio in the considered exclusive reaction is vary favorable which thereby could serve as a good probe for Technicolor dynamics searches at the LHC. |
1306.1597 | Alfredo Vega Dr. | Alfredo Vega, Ivan Schmidt, Thomas Gutsche and Valery E. Lyubovitskij | Nucleon GPDs in a light-front quark model derived from soft-wall AdS/QCD | null | null | null | null | hep-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study the helicity-independent generalized parton distributions of
nucleons in the zero skewness case, based on a particular light-front quark
model derived in a soft-wall AdS/QCD approach.
| [
{
"created": "Fri, 7 Jun 2013 03:17:59 GMT",
"version": "v1"
}
] | 2013-06-10 | [
[
"Vega",
"Alfredo",
""
],
[
"Schmidt",
"Ivan",
""
],
[
"Gutsche",
"Thomas",
""
],
[
"Lyubovitskij",
"Valery E.",
""
]
] | We study the helicity-independent generalized parton distributions of nucleons in the zero skewness case, based on a particular light-front quark model derived in a soft-wall AdS/QCD approach. |
hep-ph/9212284 | Daniel Ng | Daniel Ng | The electroweak theory of SU(3) $\times$ U(1) | 19 pages (3 figures are not included), TRI-PP-92-125 | Phys.Rev.D49:4805-4811,1994 | 10.1103/PhysRevD.49.4805 | null | hep-ph | null | An electroweak model of SU(3) $\times$ U(1) gauge group is studied. {}From
the group theoretical constraint, the symmetry breaking of this model to the
standard model occurs at 1.7~TeV or lower. Hence the mass of the new neutral
gauge boson is less than 1.7 TeV. The $Y^\pm$ and $Y^{\pm\pm}$ masses are found
to be less than half of the $Z_2$ mass. Thus, the decays $Z_2 \to Y^{++}
Y^{--}$ with $Y^{++} \to 2\ell^+ \: (\ell \!=\! e,\mu,\tau)$ is allowed,
providing spectacular signatures at future colliders. {}From the
flavor-changing neutral current processes, the representations of quarks can be
uniquely determined. The neutrino-isoscalar scattering experiments are also
considered.
| [
{
"created": "Fri, 18 Dec 1992 19:49:04 GMT",
"version": "v1"
}
] | 2011-07-19 | [
[
"Ng",
"Daniel",
""
]
] | An electroweak model of SU(3) $\times$ U(1) gauge group is studied. {}From the group theoretical constraint, the symmetry breaking of this model to the standard model occurs at 1.7~TeV or lower. Hence the mass of the new neutral gauge boson is less than 1.7 TeV. The $Y^\pm$ and $Y^{\pm\pm}$ masses are found to be less than half of the $Z_2$ mass. Thus, the decays $Z_2 \to Y^{++} Y^{--}$ with $Y^{++} \to 2\ell^+ \: (\ell \!=\! e,\mu,\tau)$ is allowed, providing spectacular signatures at future colliders. {}From the flavor-changing neutral current processes, the representations of quarks can be uniquely determined. The neutrino-isoscalar scattering experiments are also considered. |
hep-ph/9212308 | Bern | Z. Bern, L. Dixon and D.A. Kosower | Dimensionally Regulated One-Loop Integrals | 13 pages, SLAC-PUB-6001 (T), CERN-TH.6756/92, UCLA/92/42 | Phys.Lett.B302:299-308,1993; ERRATUM-ibid.B318:649,1993 | 10.1016/0370-2693(93)90400-C | null | hep-ph hep-th | null | We describe methods for evaluating one-loop integrals in $4-2\e$ dimensions.
We give a recursion relation that expresses the scalar $n$-point integral as a
cyclicly symmetric combination of $(n-1)$-point integrals. The computation of
such integrals thus reduces to the calculation of box diagrams ($n=4$). The
tensor integrals required in gauge theory may be obtained by differentiating
the scalar integral with respect to certain combinations of the kinematic
variables. Such relations also lead to differential equations for scalar
integrals. For box integrals with massless internal lines these differential
equations are easy to solve.
| [
{
"created": "Thu, 24 Dec 1992 22:32:49 GMT",
"version": "v1"
}
] | 2008-11-26 | [
[
"Bern",
"Z.",
""
],
[
"Dixon",
"L.",
""
],
[
"Kosower",
"D. A.",
""
]
] | We describe methods for evaluating one-loop integrals in $4-2\e$ dimensions. We give a recursion relation that expresses the scalar $n$-point integral as a cyclicly symmetric combination of $(n-1)$-point integrals. The computation of such integrals thus reduces to the calculation of box diagrams ($n=4$). The tensor integrals required in gauge theory may be obtained by differentiating the scalar integral with respect to certain combinations of the kinematic variables. Such relations also lead to differential equations for scalar integrals. For box integrals with massless internal lines these differential equations are easy to solve. |
2103.11593 | Suraj Prakash | Supratim Das Bakshi, Joydeep Chakrabortty, Suraj Prakash, Shakeel Ur
Rahaman, Michael Spannowsky | EFT Diagrammatica: UV Roots of the CP-conserving SMEFT | 37 pages, 11 figures | null | null | IPPP/20/86 | hep-ph hep-ex hep-th | http://creativecommons.org/licenses/by-nc-sa/4.0/ | Effective Field Theories are an established framework to bridge the gap
between UV and low energy theories. In the context of the Standard Model, the
bottom-up approach extends its operator set and thus equips us to astutely
probe its observables while encapsulating indirect evidence of unknown high
scale theories. While the top-down approach, on the other hand, employs
functional techniques to integrate out the heavy fields from a BSM Lagrangian
leading to a set of SMEFT operators. An intricate interplay of the two
approaches enhances the efficacy of the SMEFT in making meaningful predictions
while providing a platform for conducting a coherent comparison of new physics
scenarios. However, while the bottom-up approach fails to indicate the origin
of the effective operators, the top-down approach is highly dependent on the
specific model assumptions of the UV theory. We, for the first time, are
proposing a diagrammatic approach to establish selection criteria for the
allowed heavy field representations corresponding to each SMEFT operator. This,
in turn, paves the way to construct observable driven new physics models. While
we take a predominantly minimalistic approach, we also highlight the necessity
for non-minimal interactions for certain operators.
| [
{
"created": "Mon, 22 Mar 2021 05:42:37 GMT",
"version": "v1"
}
] | 2021-03-23 | [
[
"Bakshi",
"Supratim Das",
""
],
[
"Chakrabortty",
"Joydeep",
""
],
[
"Prakash",
"Suraj",
""
],
[
"Rahaman",
"Shakeel Ur",
""
],
[
"Spannowsky",
"Michael",
""
]
] | Effective Field Theories are an established framework to bridge the gap between UV and low energy theories. In the context of the Standard Model, the bottom-up approach extends its operator set and thus equips us to astutely probe its observables while encapsulating indirect evidence of unknown high scale theories. While the top-down approach, on the other hand, employs functional techniques to integrate out the heavy fields from a BSM Lagrangian leading to a set of SMEFT operators. An intricate interplay of the two approaches enhances the efficacy of the SMEFT in making meaningful predictions while providing a platform for conducting a coherent comparison of new physics scenarios. However, while the bottom-up approach fails to indicate the origin of the effective operators, the top-down approach is highly dependent on the specific model assumptions of the UV theory. We, for the first time, are proposing a diagrammatic approach to establish selection criteria for the allowed heavy field representations corresponding to each SMEFT operator. This, in turn, paves the way to construct observable driven new physics models. While we take a predominantly minimalistic approach, we also highlight the necessity for non-minimal interactions for certain operators. |
hep-ph/0611300 | Mikko Laine | M. Laine, O. Philipsen, P. Romatschke, M. Tassler | Real-time static potential in hot QCD | 20 pages. v2: a number of clarifications and a few references added;
published version | JHEP 0703:054,2007 | 10.1088/1126-6708/2007/03/054 | null | hep-ph | null | We derive a static potential for a heavy quark-antiquark pair propagating in
Minkowski time at finite temperature, by defining a suitable gauge-invariant
Green's function and computing it to first non-trivial order in Hard Thermal
Loop resummed perturbation theory. The resulting Debye-screened potential could
be used in models that attempt to describe the ``melting'' of heavy quarkonium
at high temperatures. We show, in particular, that the potential develops an
imaginary part, implying that thermal effects generate a finite width for the
quarkonium peak in the dilepton production rate. For quarkonium with a very
heavy constituent mass M, the width can be ignored for T \lsim g^2 M/12\pi,
where g^2 is the strong gauge coupling; for a physical case like bottomonium,
it could become important at temperatures as low as 250 MeV. Finally, we point
out that the physics related to the finite width originates from the
Landau-damping of low-frequency gauge fields, and could be studied
non-perturbatively by making use of the classical approximation.
| [
{
"created": "Thu, 23 Nov 2006 16:00:10 GMT",
"version": "v1"
},
{
"created": "Wed, 14 Mar 2007 14:02:28 GMT",
"version": "v2"
}
] | 2010-10-27 | [
[
"Laine",
"M.",
""
],
[
"Philipsen",
"O.",
""
],
[
"Romatschke",
"P.",
""
],
[
"Tassler",
"M.",
""
]
] | We derive a static potential for a heavy quark-antiquark pair propagating in Minkowski time at finite temperature, by defining a suitable gauge-invariant Green's function and computing it to first non-trivial order in Hard Thermal Loop resummed perturbation theory. The resulting Debye-screened potential could be used in models that attempt to describe the ``melting'' of heavy quarkonium at high temperatures. We show, in particular, that the potential develops an imaginary part, implying that thermal effects generate a finite width for the quarkonium peak in the dilepton production rate. For quarkonium with a very heavy constituent mass M, the width can be ignored for T \lsim g^2 M/12\pi, where g^2 is the strong gauge coupling; for a physical case like bottomonium, it could become important at temperatures as low as 250 MeV. Finally, we point out that the physics related to the finite width originates from the Landau-damping of low-frequency gauge fields, and could be studied non-perturbatively by making use of the classical approximation. |
2006.15333 | Fu-Hu Liu | Li-Li Li, Fu-Hu Liu, Khusniddin K. Olimov | Excitation Functions of Tsallis-like Parameters in High-Energy
Nucleus-Nucleus Collisions | 22 pages, 7 figures. Special Issue "Hydrodynamics and Thermodynamics
in High Energy Physics" in Entropy, accepted | Entropy 23, 478 (2021) (23 pages) | 10.3390/e23040478 | null | hep-ph hep-ex nucl-ex nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The transverse momentum spectra of charged pions, kaons, and protons produced
at mid-rapidity in central nucleus-nucleus (AA) collisions at high energies are
analyzed by considering particles to be created from two participant partons
which are assumed to be contributors from the collision system. Each
participant (contributor) parton is assumed to contribute to the transverse
momentum by a Tsallis-like function. The contributions of the two participant
partons are regarded as the two components of transverse momentum of the
identified particle. The experimental data measured in high-energy AA
collisions by international collaborations are studied. The excitation
functions of kinetic freeze-out temperature and transverse flow velocity are
extracted. The two parameters increase quickly from $\approx3$ to $\approx10$
GeV (exactly from 2.7 to 7.7 GeV) and then slowly at above 10 GeV with the
increase of collision energy. In particular, there is a plateau from near 10
GeV to 200 GeV in the excitation function of kinetic freeze-out temperature.
| [
{
"created": "Sat, 27 Jun 2020 10:06:55 GMT",
"version": "v1"
},
{
"created": "Tue, 17 Nov 2020 00:36:22 GMT",
"version": "v2"
},
{
"created": "Mon, 22 Mar 2021 16:39:12 GMT",
"version": "v3"
},
{
"created": "Sun, 18 Apr 2021 09:49:08 GMT",
"version": "v4"
}
] | 2021-04-20 | [
[
"Li",
"Li-Li",
""
],
[
"Liu",
"Fu-Hu",
""
],
[
"Olimov",
"Khusniddin K.",
""
]
] | The transverse momentum spectra of charged pions, kaons, and protons produced at mid-rapidity in central nucleus-nucleus (AA) collisions at high energies are analyzed by considering particles to be created from two participant partons which are assumed to be contributors from the collision system. Each participant (contributor) parton is assumed to contribute to the transverse momentum by a Tsallis-like function. The contributions of the two participant partons are regarded as the two components of transverse momentum of the identified particle. The experimental data measured in high-energy AA collisions by international collaborations are studied. The excitation functions of kinetic freeze-out temperature and transverse flow velocity are extracted. The two parameters increase quickly from $\approx3$ to $\approx10$ GeV (exactly from 2.7 to 7.7 GeV) and then slowly at above 10 GeV with the increase of collision energy. In particular, there is a plateau from near 10 GeV to 200 GeV in the excitation function of kinetic freeze-out temperature. |
2210.03199 | Patrick Draper | Matthew Baumgart, Fady Bishara, Tomas Brauner, Joachim Brod, Giovanni
Cabass, Timothy Cohen, Nathaniel Craig, Claudia de Rham, Patrick Draper, A.
Liam Fitzpatrick, Martin Gorbahn, Sean Hartnoll, Mikhail Ivanov, Pavel
Kovtun, Sandipan Kundu, Matthew Lewandowski, Hong Liu, Xiaochuan Lu, Mark
Mezei, Mehrdad Mirbabayi, Ulserik Moldanazarova, Alberto Nicolis, Riccardo
Penco, Walter Goldberger, Matthew Reece, Nicholas L. Rodd, Ira Rothstein,
Shu-Heng Shao, Will Shepherd, Marko Simonovic, Mikhail Solon, Dam Thanh Son,
Robert Szafron, Andrew Tolley, Zhengkang Zhang, Shuang-Yong Zhou, Jure Zupan | Snowmass Theory Frontier: Effective Field Theory | 12 pages | null | null | null | hep-ph astro-ph.CO hep-ex hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We summarize recent progress in the development, application, and
understanding of effective field theories and highlight promising directions
for future research. This Report is prepared as the TF02 "Effective Field
Theory" topical group summary for the Theory Frontier as part of the Snowmass
2021 process.
| [
{
"created": "Thu, 6 Oct 2022 20:41:14 GMT",
"version": "v1"
}
] | 2022-10-10 | [
[
"Baumgart",
"Matthew",
""
],
[
"Bishara",
"Fady",
""
],
[
"Brauner",
"Tomas",
""
],
[
"Brod",
"Joachim",
""
],
[
"Cabass",
"Giovanni",
""
],
[
"Cohen",
"Timothy",
""
],
[
"Craig",
"Nathaniel",
""
],
[
"de Rham",
"Claudia",
""
],
[
"Draper",
"Patrick",
""
],
[
"Fitzpatrick",
"A. Liam",
""
],
[
"Gorbahn",
"Martin",
""
],
[
"Hartnoll",
"Sean",
""
],
[
"Ivanov",
"Mikhail",
""
],
[
"Kovtun",
"Pavel",
""
],
[
"Kundu",
"Sandipan",
""
],
[
"Lewandowski",
"Matthew",
""
],
[
"Liu",
"Hong",
""
],
[
"Lu",
"Xiaochuan",
""
],
[
"Mezei",
"Mark",
""
],
[
"Mirbabayi",
"Mehrdad",
""
],
[
"Moldanazarova",
"Ulserik",
""
],
[
"Nicolis",
"Alberto",
""
],
[
"Penco",
"Riccardo",
""
],
[
"Goldberger",
"Walter",
""
],
[
"Reece",
"Matthew",
""
],
[
"Rodd",
"Nicholas L.",
""
],
[
"Rothstein",
"Ira",
""
],
[
"Shao",
"Shu-Heng",
""
],
[
"Shepherd",
"Will",
""
],
[
"Simonovic",
"Marko",
""
],
[
"Solon",
"Mikhail",
""
],
[
"Son",
"Dam Thanh",
""
],
[
"Szafron",
"Robert",
""
],
[
"Tolley",
"Andrew",
""
],
[
"Zhang",
"Zhengkang",
""
],
[
"Zhou",
"Shuang-Yong",
""
],
[
"Zupan",
"Jure",
""
]
] | We summarize recent progress in the development, application, and understanding of effective field theories and highlight promising directions for future research. This Report is prepared as the TF02 "Effective Field Theory" topical group summary for the Theory Frontier as part of the Snowmass 2021 process. |
1212.4825 | T. Lappi | T. Lappi and H. M\"antysaari | On the running coupling in the JIMWLK equation | 13 pages, 11 figures, RevTeX | Eur. Phys. J. C73 (2013) 2307 | 10.1140/epjc/s10052-013-2307-z | null | hep-ph nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We propose a new method to implement the running coupling constant in the
JIMWLK equation, imposing the scale dependence on the correlation function of
the random noise in the Langevin formulation. We interpret this scale choice as
the transverse momentum of the emitted gluon in one step of the evolution and
show that it is related to the "Balitsky" prescription for the BK equation.
This slows down the evolution speed of a practical solution of the JIMWLK
equation, bringing it closer to the x-dependence inferred from fits to HERA
data. We further study our proposal by a numerical comparison of the BK and
JIMWLK equations.
| [
{
"created": "Wed, 19 Dec 2012 20:44:30 GMT",
"version": "v1"
}
] | 2013-03-29 | [
[
"Lappi",
"T.",
""
],
[
"Mäntysaari",
"H.",
""
]
] | We propose a new method to implement the running coupling constant in the JIMWLK equation, imposing the scale dependence on the correlation function of the random noise in the Langevin formulation. We interpret this scale choice as the transverse momentum of the emitted gluon in one step of the evolution and show that it is related to the "Balitsky" prescription for the BK equation. This slows down the evolution speed of a practical solution of the JIMWLK equation, bringing it closer to the x-dependence inferred from fits to HERA data. We further study our proposal by a numerical comparison of the BK and JIMWLK equations. |
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