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|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
hep-ph/0101260 | Wolfgang Hollik | A. Freitas, S. Heinemeyer, W. Hollik, W. Walter, G. Weiglein | Two-loop electroweak contributions to $\Delta r$ | 14 pages, including 4 figures. Presented at the 5th International
Symposium on Radiative Corrections, (RADCOR-2000), Carmel CA, USA, 11-15
September 2000 | null | null | null | hep-ph | null | A review is given on the quantum correction $\Delta r$ in the $W$--$Z$ mass
correlation at the electroweak two-loop level, as derived from the calculation
of the muon lifetime in the Standard Model. Exact results for $\Delta r$ and
the $W$-mass prediction including ${\mathcal{O}}(\alpha^2)$ corrections with
fermion loops are presented and compared with previous results of a
next-to-leading order expansion in the top-quark mass.
| [
{
"created": "Tue, 23 Jan 2001 13:53:23 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Freitas",
"A.",
""
],
[
"Heinemeyer",
"S.",
""
],
[
"Hollik",
"W.",
""
],
[
"Walter",
"W.",
""
],
[
"Weiglein",
"G.",
""
]
] | A review is given on the quantum correction $\Delta r$ in the $W$--$Z$ mass correlation at the electroweak two-loop level, as derived from the calculation of the muon lifetime in the Standard Model. Exact results for $\Delta r$ and the $W$-mass prediction including ${\mathcal{O}}(\alpha^2)$ corrections with fermion loops are presented and compared with previous results of a next-to-leading order expansion in the top-quark mass. |
1111.6346 | Chung-Lin Shan | Chung-Lin Shan | Analyzing direct dark matter detection data with unrejected background
events by the AMIDAS website | 9 pages, 10 eps figures, 1 table, to appear in the proceedings of the
Seventh International Workshop on the Dark Side of the Universe (DSU 2011),
September 26-30, 2011, Beijing, China | null | 10.1088/1742-6596/384/1/012006 | null | hep-ph astro-ph.HE hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this talk I have presented the data analysis results of extracting
properties of halo WIMPs: the mass and the (ratios between the)
spin-independent and spin-dependent couplings/cross sections on nucleons by the
AMIDAS website by taking into account possible unrejected background events in
the analyzed data sets. Although non-standard astronomical setup has been used
to generate pseudodata sets for our analyses, it has been found that, without
prior information/assumption about the local density and velocity distribution
of halo Dark Matter, these WIMP properties have been reconstructed with ~ 2% to
<~ 30% deviations from the input values.
| [
{
"created": "Mon, 28 Nov 2011 05:18:24 GMT",
"version": "v1"
}
] | 2015-06-03 | [
[
"Shan",
"Chung-Lin",
""
]
] | In this talk I have presented the data analysis results of extracting properties of halo WIMPs: the mass and the (ratios between the) spin-independent and spin-dependent couplings/cross sections on nucleons by the AMIDAS website by taking into account possible unrejected background events in the analyzed data sets. Although non-standard astronomical setup has been used to generate pseudodata sets for our analyses, it has been found that, without prior information/assumption about the local density and velocity distribution of halo Dark Matter, these WIMP properties have been reconstructed with ~ 2% to <~ 30% deviations from the input values. |
2112.01412 | Renaud Boussarie | Renaud Boussarie and Yacine Mehtar-Tani | Gluon-mediated inclusive Deep Inelastic Scattering from Regge to Bjorken
kinematics | 53 pages, 7 figures | null | 10.1007/JHEP07(2022)080 | null | hep-ph nucl-th | http://creativecommons.org/licenses/by/4.0/ | We revisit high energy factorization for gluon mediated inclusive Deep
Inelastic Scattering (DIS) for which we propose a new semi-classical approach
that accounts systematically for the longitudinal extent of the target in
contrast with the shockwave limit. In this framework, based on a partial twist
expansion, we derive a factorization formula that involves a new gauge
invariant unintegrated gluon distribution which depends explicitly on the
Feynman $x$ variable. It is shown that both the Regge and Bjorken limits are
recovered in this approach. We reproduce in particular the full one loop
inclusive DIS cross-section in the leading twist approximation and the
all-twist dipole factorization formula in the strict $x=0$ limit. Although
quantum evolution is not discussed explicitly in this work, we argue that the
proper treatment of the $x$ dependence of the gluon distribution encompasses
the kinematic constraint that must be imposed on the phase-space of gluon
fluctuations in the target to ensure stability of small-$x$ evolution.
| [
{
"created": "Thu, 2 Dec 2021 17:00:16 GMT",
"version": "v1"
}
] | 2022-08-10 | [
[
"Boussarie",
"Renaud",
""
],
[
"Mehtar-Tani",
"Yacine",
""
]
] | We revisit high energy factorization for gluon mediated inclusive Deep Inelastic Scattering (DIS) for which we propose a new semi-classical approach that accounts systematically for the longitudinal extent of the target in contrast with the shockwave limit. In this framework, based on a partial twist expansion, we derive a factorization formula that involves a new gauge invariant unintegrated gluon distribution which depends explicitly on the Feynman $x$ variable. It is shown that both the Regge and Bjorken limits are recovered in this approach. We reproduce in particular the full one loop inclusive DIS cross-section in the leading twist approximation and the all-twist dipole factorization formula in the strict $x=0$ limit. Although quantum evolution is not discussed explicitly in this work, we argue that the proper treatment of the $x$ dependence of the gluon distribution encompasses the kinematic constraint that must be imposed on the phase-space of gluon fluctuations in the target to ensure stability of small-$x$ evolution. |
1210.1994 | Gilberto Tavares-Velasco | A. Moyotl, G. Tavares-Velasco | Weak properties of the tau lepton via a spin-0 unparticle | 9 pages, 10 figures, 2 tables | Phys.Rev. D86 (2012) 013014 | 10.1103/PhysRevD.86.013014 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We consider a spin-0 unparticle and calculate its contribution to the weak
properties of a fermion, which in the proper limit reduce to previously
reported results for the electromagnetic properties. We then obtain an estimate
for the electromagnetic and weak properties of the tau lepton. For the
unparticle parameters, we consider the most recent bounds from the lepton
flavor violating decay tau -> 3 mu, the muon anomalous magnetic moment, and the
data for monojet production plus missing transverse energy at the LHC. In the
most promising promising scenario, it is found that the unparticle
contributions to the tau electromagnetic properties can be larger than the
contributions predicted by the standard model (SM) and some of its extensions,
such as the SeeSaw model and extensions of the minimal supersymmetric standard
model (MSSM) with a mirror fourth generation and vectorlike multiplets. As for
the contributions to the weak properties, they are larger than the SM
contributions but are much smaller than the current experimental limits. We
also discuss the case of the electromagnetic and weak properties of the bottom
and top quarks.
| [
{
"created": "Sat, 6 Oct 2012 19:48:41 GMT",
"version": "v1"
}
] | 2012-10-09 | [
[
"Moyotl",
"A.",
""
],
[
"Tavares-Velasco",
"G.",
""
]
] | We consider a spin-0 unparticle and calculate its contribution to the weak properties of a fermion, which in the proper limit reduce to previously reported results for the electromagnetic properties. We then obtain an estimate for the electromagnetic and weak properties of the tau lepton. For the unparticle parameters, we consider the most recent bounds from the lepton flavor violating decay tau -> 3 mu, the muon anomalous magnetic moment, and the data for monojet production plus missing transverse energy at the LHC. In the most promising promising scenario, it is found that the unparticle contributions to the tau electromagnetic properties can be larger than the contributions predicted by the standard model (SM) and some of its extensions, such as the SeeSaw model and extensions of the minimal supersymmetric standard model (MSSM) with a mirror fourth generation and vectorlike multiplets. As for the contributions to the weak properties, they are larger than the SM contributions but are much smaller than the current experimental limits. We also discuss the case of the electromagnetic and weak properties of the bottom and top quarks. |
0909.1535 | Antonio Palazzo | A. Palazzo, J. W. F. Valle | Confusing non-zero theta_13 with non-standard interactions in the solar
neutrino sector | 5 pages, 3 figures; minor changes in the text; references added;
matches version published in PRD (Rapid Communications) | Phys.Rev.D80:091301,2009 | 10.1103/PhysRevD.80.091301 | IFIC/09-41 | hep-ph astro-ph.SR hep-ex nucl-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Solar and KamLAND data are in slight tension when interpreted in the standard
two-flavor oscillations framework and this may be alleviated allowing for a
non-zero value of the mixing angle theta_13. Here we show that, likewise,
non-standard flavor-changing interactions (FCI), possibly intervening in the
propagation of solar neutrinos, are equally able to alleviate this tension and
therefore constitute a potential source of confusion in the determination of
theta_13. By performing a full three-flavor analysis of solar and KamLAND data
in presence of FCI we provide a quantitative description of the degeneracy
existing between theta_13 and the vectorial coupling eps_e\tau^dV
characterizing the non-standard transitions between nu_e and nu_tau in the
forward scattering process with d-type quarks. We find that couplings with
magnitude eps_e\tau^dV ~ 10%, compatible with the existing bounds, can mimic
the non-zero values of theta_13 indicated by the latest analyses.
| [
{
"created": "Tue, 8 Sep 2009 18:12:35 GMT",
"version": "v1"
},
{
"created": "Tue, 1 Dec 2009 16:41:45 GMT",
"version": "v2"
}
] | 2009-12-01 | [
[
"Palazzo",
"A.",
""
],
[
"Valle",
"J. W. F.",
""
]
] | Solar and KamLAND data are in slight tension when interpreted in the standard two-flavor oscillations framework and this may be alleviated allowing for a non-zero value of the mixing angle theta_13. Here we show that, likewise, non-standard flavor-changing interactions (FCI), possibly intervening in the propagation of solar neutrinos, are equally able to alleviate this tension and therefore constitute a potential source of confusion in the determination of theta_13. By performing a full three-flavor analysis of solar and KamLAND data in presence of FCI we provide a quantitative description of the degeneracy existing between theta_13 and the vectorial coupling eps_e\tau^dV characterizing the non-standard transitions between nu_e and nu_tau in the forward scattering process with d-type quarks. We find that couplings with magnitude eps_e\tau^dV ~ 10%, compatible with the existing bounds, can mimic the non-zero values of theta_13 indicated by the latest analyses. |
hep-ph/9701242 | Yu-Qi Chen | Eric Braaten and Yu-Qi Chen | Calculation of P-Wave Charmonium Decay Rates Using Dimensional
Regularization | 29 pages, LaTex, 5 figes | Phys.Rev. D55 (1997) 7152-7164 | 10.1103/PhysRevD.55.7152 | OHSTPY-HEP-T-97-001 | hep-ph | null | Contributions to the decay rates of P-wave charmonium states that are
proportional to $n_f \alpha_s^3$, where $n_f$ is the number of flavors of light
quarks, are calculated in the framework of nonrelativistic QCD using the
threshold expansion method. Dimensional regularization is used to regularize
the infrared divergences that arise from the emission of a soft gluon. Our
results are consistent with the original calculations of Barbieri et al.
| [
{
"created": "Tue, 7 Jan 1997 17:47:23 GMT",
"version": "v1"
}
] | 2009-10-30 | [
[
"Braaten",
"Eric",
""
],
[
"Chen",
"Yu-Qi",
""
]
] | Contributions to the decay rates of P-wave charmonium states that are proportional to $n_f \alpha_s^3$, where $n_f$ is the number of flavors of light quarks, are calculated in the framework of nonrelativistic QCD using the threshold expansion method. Dimensional regularization is used to regularize the infrared divergences that arise from the emission of a soft gluon. Our results are consistent with the original calculations of Barbieri et al. |
hep-ph/0208167 | Zuo-Hong Li | Zuo-Hong Li, Xiang-Yao Wu and Tao Huang | Reexamined radiative Decay $ B_{q}^*\to B_{q}\gamma $ in Light Cone QCD | Latex, 15 pages, 2 figures. To appear in JPG | null | null | null | hep-ph | null | The radiative decay $ B_{q}^*\to B_{q}\gamma(q=u,d, or s) $ is reexamined
with a modified light-cone QCD sum rule method, in which adequate chiral
operators are chosen as the interpolating fields in the correlators used for a
sum rule estimate of the relevant coupling $ g_{B_{q}^*B_{q}\gamma} $. The
resulting sum rules not only show the physical picture consistent with the
underlying physics in $ B_{q}^*\to B_{q}\gamma $ but also avoid the pollution
by the nonlocal matrix element $< \gamma(q) | \bar{q}(x)
\gamma_{\mu}\gamma_{5}q(0) | 0>$, which starts with twist-3 and thus may bring
a large uncertainty to the sum rule predictions. Also, a comparison is made
with the previous results from light-cone QCD sum rules and chiral perturbation
theory.
| [
{
"created": "Sat, 17 Aug 2002 02:26:07 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Li",
"Zuo-Hong",
""
],
[
"Wu",
"Xiang-Yao",
""
],
[
"Huang",
"Tao",
""
]
] | The radiative decay $ B_{q}^*\to B_{q}\gamma(q=u,d, or s) $ is reexamined with a modified light-cone QCD sum rule method, in which adequate chiral operators are chosen as the interpolating fields in the correlators used for a sum rule estimate of the relevant coupling $ g_{B_{q}^*B_{q}\gamma} $. The resulting sum rules not only show the physical picture consistent with the underlying physics in $ B_{q}^*\to B_{q}\gamma $ but also avoid the pollution by the nonlocal matrix element $< \gamma(q) | \bar{q}(x) \gamma_{\mu}\gamma_{5}q(0) | 0>$, which starts with twist-3 and thus may bring a large uncertainty to the sum rule predictions. Also, a comparison is made with the previous results from light-cone QCD sum rules and chiral perturbation theory. |
1310.2825 | Jan Heisig | Jan Heisig, J\"orn Kersten, Boris Panes, Tania Robens | A survey for low stau yields in the MSSM | 60 pages + refereces, 60 eps figures, v2: references added,
presentation improved, figure 9 changed, results and conclusions unchanged,
matches journal version | JHEP04(2014)053 | 10.1007/JHEP04(2014)053 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study the implications of LHC results for the abundance of long-lived
staus after freeze-out from thermal equilibrium in a super-WIMP dark matter
scenario. We classify regions in the MSSM parameter space according to the stau
yield, considering all possible co-annihilation effects as well as the effects
of resonances and large Higgs-sfermion couplings. Afterwards, we examine the
viability of these regions after imposing experimental and theoretical
constraints, in particular a Higgs mass around 125 GeV and null-searches for
heavy stable charged particles (HSCP) at the LHC. We work in a pMSSM framework
and perform a Monte Carlo scan over the parameter space. To interpret the HSCP
searches in our scenario, we consider all potentially important superparticle
production processes, developing a fast estimator for NLO cross sections for
electroweak and strong production at the LHC. After applying all constraints,
we find that stau yields below 10^-14 occur only for resonant annihilation via
a heavy Higgs in combination with either co-annihilation or large left-right
stau mixing. We encounter allowed points with yields as low as 2x10^-16, thus
satisfying limits from big bang nucleosynthesis even for large stau lifetimes.
| [
{
"created": "Thu, 10 Oct 2013 14:13:15 GMT",
"version": "v1"
},
{
"created": "Fri, 4 Apr 2014 10:30:03 GMT",
"version": "v2"
}
] | 2014-04-16 | [
[
"Heisig",
"Jan",
""
],
[
"Kersten",
"Jörn",
""
],
[
"Panes",
"Boris",
""
],
[
"Robens",
"Tania",
""
]
] | We study the implications of LHC results for the abundance of long-lived staus after freeze-out from thermal equilibrium in a super-WIMP dark matter scenario. We classify regions in the MSSM parameter space according to the stau yield, considering all possible co-annihilation effects as well as the effects of resonances and large Higgs-sfermion couplings. Afterwards, we examine the viability of these regions after imposing experimental and theoretical constraints, in particular a Higgs mass around 125 GeV and null-searches for heavy stable charged particles (HSCP) at the LHC. We work in a pMSSM framework and perform a Monte Carlo scan over the parameter space. To interpret the HSCP searches in our scenario, we consider all potentially important superparticle production processes, developing a fast estimator for NLO cross sections for electroweak and strong production at the LHC. After applying all constraints, we find that stau yields below 10^-14 occur only for resonant annihilation via a heavy Higgs in combination with either co-annihilation or large left-right stau mixing. We encounter allowed points with yields as low as 2x10^-16, thus satisfying limits from big bang nucleosynthesis even for large stau lifetimes. |
1908.05588 | Christoph Englert | Christoph Englert, Peter Galler, Chris D. White | Effective field theory and scalar extensions of the top quark sector | 12 pages, 9 figures, v2: version published in PRD | Phys. Rev. D 101, 035035 (2020) | 10.1103/PhysRevD.101.035035 | QMUL-PH-19-19 | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Effective field theory (EFT) approaches are widely used at the LHC, such that
it is important to study their validity, and ease of matching to specific new
physics models. In this paper, we consider an extension of the SM in which a
top quark couples to a new heavy scalar. We find the dimension six operators
generated by this theory at low energy, and match the EFT to the full theory up
to NLO precision in the simplified model coupling. We then examine the range of
validity of the EFT description in top pair production, finding excellent
validity even if the scalar mass is only slightly above LHC energies, provided
NLO corrections are included. In the absence of the latter, the LO EFT
overestimates kinematic distributions, such that over-optimistic constraints on
BSM contributions are obtained. We next examine the constraints on the EFT and
full models that are expected to be obtained from both top pair and four top
production at the LHC, finding for low scalar masses that both processes show
similar exclusion power. However, for larger masses, estimated LHC
uncertainties push constraints into the non-perturbative regime, where the full
model is difficult to analyse, and thus not perturbatively matchable to the
EFT. This highlights the necessity to improve uncertainties of SM hypotheses in
top final states.
| [
{
"created": "Thu, 15 Aug 2019 15:34:57 GMT",
"version": "v1"
},
{
"created": "Mon, 10 Feb 2020 10:53:45 GMT",
"version": "v2"
}
] | 2020-03-04 | [
[
"Englert",
"Christoph",
""
],
[
"Galler",
"Peter",
""
],
[
"White",
"Chris D.",
""
]
] | Effective field theory (EFT) approaches are widely used at the LHC, such that it is important to study their validity, and ease of matching to specific new physics models. In this paper, we consider an extension of the SM in which a top quark couples to a new heavy scalar. We find the dimension six operators generated by this theory at low energy, and match the EFT to the full theory up to NLO precision in the simplified model coupling. We then examine the range of validity of the EFT description in top pair production, finding excellent validity even if the scalar mass is only slightly above LHC energies, provided NLO corrections are included. In the absence of the latter, the LO EFT overestimates kinematic distributions, such that over-optimistic constraints on BSM contributions are obtained. We next examine the constraints on the EFT and full models that are expected to be obtained from both top pair and four top production at the LHC, finding for low scalar masses that both processes show similar exclusion power. However, for larger masses, estimated LHC uncertainties push constraints into the non-perturbative regime, where the full model is difficult to analyse, and thus not perturbatively matchable to the EFT. This highlights the necessity to improve uncertainties of SM hypotheses in top final states. |
1105.1332 | Spencer Chang | Spencer Chang, Can Kilic, and Takemichi Okui | Measuring Top Squark Interactions With The Standard Model Through
Associated Production | 5 pages, 3 figures, revtex; v2, added reference and small changes | Phys.Rev. D84 (2011) 035015 | 10.1103/PhysRevD.84.035015 | RUNHETC-2011-10 | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | A new particle's interactions can be measured at colliders, by observing its
associated production with Standard Model particles. We focus on the case of a
collider-stable right-handed top squark and study the LHC sensitivities to its
couplings to the photon, Z, and the Higgs boson. Such measurements determine
the top squark's charge, mixing angle and coupling to the electroweak symmetry
breaking sector. Determining these couplings can provide strong evidence for
the supersymmetric solution to the hierarchy problem. Our analysis shows that
the LHC has great prospects for measuring the photon and Higgs couplings, but
will require a very high luminosity to measure the Z coupling.
| [
{
"created": "Fri, 6 May 2011 17:08:15 GMT",
"version": "v1"
},
{
"created": "Tue, 24 May 2011 21:06:07 GMT",
"version": "v2"
}
] | 2013-03-11 | [
[
"Chang",
"Spencer",
""
],
[
"Kilic",
"Can",
""
],
[
"Okui",
"Takemichi",
""
]
] | A new particle's interactions can be measured at colliders, by observing its associated production with Standard Model particles. We focus on the case of a collider-stable right-handed top squark and study the LHC sensitivities to its couplings to the photon, Z, and the Higgs boson. Such measurements determine the top squark's charge, mixing angle and coupling to the electroweak symmetry breaking sector. Determining these couplings can provide strong evidence for the supersymmetric solution to the hierarchy problem. Our analysis shows that the LHC has great prospects for measuring the photon and Higgs couplings, but will require a very high luminosity to measure the Z coupling. |
2305.11760 | Michael Fucilla | Francesco Giovanni Celiberto, Michael Fucilla, Dmitry Yu. Ivanov,
Mohammed M.A. Mohammed and Alessandro Papa | Higgs boson production at next-to-leading logarithmic accuracy | 4 pages. Contribution to the 2023 QCD session of the 57th Rencontres
de Moriond | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | It has been recently argued that the inclusive hadroproduction at the LHC of
a Higgs boson in association with a jet can be sensitive to the high-energy
dynamics. Moreover, the impact of the resummation at FCC energies is expected
to be large also in the inclusive cross section for the main Higgs production
channel in proton-proton collisions, namely the gluon fusion. As the energy
increases, a pure $k_t$-factorization framework or a collinear-factorization
approach supplemented by the high-energy resummation are adequate formalisms to
describe these processes. In both cases, the fundamental missing ingredient for
a next-to-leading logarithmic description is the Higgs boson impact factor. We
present the full next-to-leading result for the forward Higgs impact factor,
obtained in the infinite top-mass limit, discussing possible future extensions,
such as the calculation of the impact factor in the central rapidity region.
| [
{
"created": "Fri, 19 May 2023 15:45:54 GMT",
"version": "v1"
}
] | 2023-05-22 | [
[
"Celiberto",
"Francesco Giovanni",
""
],
[
"Fucilla",
"Michael",
""
],
[
"Ivanov",
"Dmitry Yu.",
""
],
[
"Mohammed",
"Mohammed M. A.",
""
],
[
"Papa",
"Alessandro",
""
]
] | It has been recently argued that the inclusive hadroproduction at the LHC of a Higgs boson in association with a jet can be sensitive to the high-energy dynamics. Moreover, the impact of the resummation at FCC energies is expected to be large also in the inclusive cross section for the main Higgs production channel in proton-proton collisions, namely the gluon fusion. As the energy increases, a pure $k_t$-factorization framework or a collinear-factorization approach supplemented by the high-energy resummation are adequate formalisms to describe these processes. In both cases, the fundamental missing ingredient for a next-to-leading logarithmic description is the Higgs boson impact factor. We present the full next-to-leading result for the forward Higgs impact factor, obtained in the infinite top-mass limit, discussing possible future extensions, such as the calculation of the impact factor in the central rapidity region. |
hep-ph/0106153 | David H. Lyth | David H. Lyth | The primordial curvature perturbation in the ekpyrotic Universe | 6 pages. The Guth-Pi-Olson formalism of the original ekpyrotic paper
translated, results from a forthcoming paper reported | Phys.Lett. B524 (2002) 1-4 | 10.1016/S0370-2693(01)01374-0 | null | hep-ph astro-ph gr-qc hep-th | null | In the ekpyrotic scenario the Universe is initially collapsing, the energy
density coming from a scalar field with a negative exponential potential. On
the basis of a calculation ignoring the gravitational back-reaction the authors
of the scenario claim that during collapse the vacuum fluctuation creates a
perturbation in the comoving curvature, which has a flat spectrum in accordance
with observation. In this note the back-reaction is included, and it is found
that the spectrum during collapse is strongly scale-dependent with negligible
magnitude. The spectrum is continuous across the bounce if the spacetime is
smooth, making it unlikely that the ekpyrotic scenario can be compatible with
observation.
| [
{
"created": "Thu, 14 Jun 2001 17:33:55 GMT",
"version": "v1"
},
{
"created": "Thu, 12 Jul 2001 15:21:40 GMT",
"version": "v2"
},
{
"created": "Sun, 19 Aug 2001 10:02:43 GMT",
"version": "v3"
}
] | 2009-11-07 | [
[
"Lyth",
"David H.",
""
]
] | In the ekpyrotic scenario the Universe is initially collapsing, the energy density coming from a scalar field with a negative exponential potential. On the basis of a calculation ignoring the gravitational back-reaction the authors of the scenario claim that during collapse the vacuum fluctuation creates a perturbation in the comoving curvature, which has a flat spectrum in accordance with observation. In this note the back-reaction is included, and it is found that the spectrum during collapse is strongly scale-dependent with negligible magnitude. The spectrum is continuous across the bounce if the spacetime is smooth, making it unlikely that the ekpyrotic scenario can be compatible with observation. |
1512.06426 | Spencer Chang | Spencer Chang | A Simple $U(1)$ Gauge Theory Explanation of the Diphoton Excess | 5 pages, 2 figures, revtex; added references, discussion and
predictions for phi decays into heavy A_x gauge boson | Phys. Rev. D 93, 055016 (2016) | 10.1103/PhysRevD.93.055016 | null | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The recent ATLAS and CMS diphoton resonance excesses are explored in a simple
$U(1)$ gauge theory extension of the Standard Model where the resonance is the
Higgs boson of the $U(1)$ symmetry breaking, $\phi$. This particle couples to
exotic quarks which, through loops, can produce a large enough rate to explain
the excess. Due to the choice of $U(1)$ charges, flavor constraints are
naturally suppressed, allowing arbitrary flavor violation in the decays of the
new quarks to up-type quarks, modifying their signal topologies. An additional
heavy quark in the model decays to the lighter exotic quark by emitting either
$\phi$ or the $U(1)$ gauge boson, $A_x$, giving extra signals containing
diphoton and digluon resonances. Finally, the new Higgs can decay into $\gamma
A_x$ and $Z A_x$, followed by $A_x$ decaying into Standard Model fermions
through kinetic mixing. Thus, this model gives interesting modified signals to
the general class of exotic quark models explaining the diphoton resonance.
| [
{
"created": "Sun, 20 Dec 2015 20:05:29 GMT",
"version": "v1"
},
{
"created": "Thu, 7 Jan 2016 01:21:37 GMT",
"version": "v2"
}
] | 2016-03-23 | [
[
"Chang",
"Spencer",
""
]
] | The recent ATLAS and CMS diphoton resonance excesses are explored in a simple $U(1)$ gauge theory extension of the Standard Model where the resonance is the Higgs boson of the $U(1)$ symmetry breaking, $\phi$. This particle couples to exotic quarks which, through loops, can produce a large enough rate to explain the excess. Due to the choice of $U(1)$ charges, flavor constraints are naturally suppressed, allowing arbitrary flavor violation in the decays of the new quarks to up-type quarks, modifying their signal topologies. An additional heavy quark in the model decays to the lighter exotic quark by emitting either $\phi$ or the $U(1)$ gauge boson, $A_x$, giving extra signals containing diphoton and digluon resonances. Finally, the new Higgs can decay into $\gamma A_x$ and $Z A_x$, followed by $A_x$ decaying into Standard Model fermions through kinetic mixing. Thus, this model gives interesting modified signals to the general class of exotic quark models explaining the diphoton resonance. |
1805.06460 | Marco Bonvini | Marco Bonvini and Simone Marzani | Four-loop splitting functions at small $x$ | 34 pages, 5 figures, 2 appendices. Version published in JHEP | JHEP 06 (2018) 145 | 10.1007/JHEP06(2018)145 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We consider the expansion of small-$x$ resummed DGLAP splitting functions at
next-to-leading logarithmic (NLL) accuracy to four-loop order, namely
next-to-next-to-next-to-leading order (N$^3$LO). From this, we extract the
exact LL and NLL small-$x$ contributions to the yet unknown N$^3$LO splitting
functions, both in the standard $\overline{MS}$ scheme and in the $Q_0
\overline{MS}$ scheme usually considered in small-$x$ literature. We show that
the impact of unknown subleading logarithmic contributions (NNLL and beyond) at
N$^3$LO is significant, thus motivating future work towards their computation.
Our results will be also needed in future to match NLL resummation to N$^3$LO
evolution. In turn, we propose an improved implementation of the small-$x$
resummation and therefore release a new version of the resummation code (HELL
3.0) which contains these changes.
| [
{
"created": "Wed, 16 May 2018 18:00:02 GMT",
"version": "v1"
},
{
"created": "Thu, 5 Jul 2018 12:01:56 GMT",
"version": "v2"
}
] | 2018-07-06 | [
[
"Bonvini",
"Marco",
""
],
[
"Marzani",
"Simone",
""
]
] | We consider the expansion of small-$x$ resummed DGLAP splitting functions at next-to-leading logarithmic (NLL) accuracy to four-loop order, namely next-to-next-to-next-to-leading order (N$^3$LO). From this, we extract the exact LL and NLL small-$x$ contributions to the yet unknown N$^3$LO splitting functions, both in the standard $\overline{MS}$ scheme and in the $Q_0 \overline{MS}$ scheme usually considered in small-$x$ literature. We show that the impact of unknown subleading logarithmic contributions (NNLL and beyond) at N$^3$LO is significant, thus motivating future work towards their computation. Our results will be also needed in future to match NLL resummation to N$^3$LO evolution. In turn, we propose an improved implementation of the small-$x$ resummation and therefore release a new version of the resummation code (HELL 3.0) which contains these changes. |
1305.7023 | Edmond Iancu | Edmond Iancu | From jet quenching to wave turbulence | 6 pages, 4 figures. Based on a talk presented at the 48th Rencontres
de Moriond: QCD and Hadronic Interactions, La Thuile, Italy, 9-16 Mar 2013 | null | null | null | hep-ph hep-ex nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We discuss average properties of the gluon cascade generated by an energetic
parton propagating through a dense QCD medium. The cascade is mostly made with
relatively soft gluons, whose production is not suppressed by the LPM effect.
Unlike for usual QCD cascades in the vacuum, where the typical splittings are
very asymmetric (soft and collinear), the medium-induced branchings are
quasi-democratic and lead to wave turbulence. This results in a very efficient
mechanism for the transport of energy at large angles with respect to the jet
axis, which might explain the di-jet asymmetry observed in Pb-Pb collisions at
the LHC.
| [
{
"created": "Thu, 30 May 2013 07:12:43 GMT",
"version": "v1"
}
] | 2013-05-31 | [
[
"Iancu",
"Edmond",
""
]
] | We discuss average properties of the gluon cascade generated by an energetic parton propagating through a dense QCD medium. The cascade is mostly made with relatively soft gluons, whose production is not suppressed by the LPM effect. Unlike for usual QCD cascades in the vacuum, where the typical splittings are very asymmetric (soft and collinear), the medium-induced branchings are quasi-democratic and lead to wave turbulence. This results in a very efficient mechanism for the transport of energy at large angles with respect to the jet axis, which might explain the di-jet asymmetry observed in Pb-Pb collisions at the LHC. |
hep-ph/0109065 | Karsten Tabelow | Meng Ta-chung | Electron as Spatiotemporal Complexity due to Self-Organized Criticality | 14 pages, including 1 figure | null | null | null | hep-ph | null | The electron, which has been pictured as an elementary particle ever since
J.J. Thomson's e/m-measurement in 1897, and the relativistic motion of which is
described by the Dirac equation, is discussed in the light of the recent
progress made in Science of Complex Systems. Theoretical arguments and
experimental evidences are presented which show that such an electron exhibits
characteristic properties of spatiotemporal complexities due to Self-Organized
Criticality (SOC). This implies in particular that, conceptually and logically,
it is neither possible nor meaningful to identify such an object with an
ordinary particle, which by definition is something that has a fixed mass
(size), a fixed lifetime, and a fixed structure.
| [
{
"created": "Fri, 7 Sep 2001 22:20:14 GMT",
"version": "v1"
}
] | 2016-09-06 | [
[
"Ta-chung",
"Meng",
""
]
] | The electron, which has been pictured as an elementary particle ever since J.J. Thomson's e/m-measurement in 1897, and the relativistic motion of which is described by the Dirac equation, is discussed in the light of the recent progress made in Science of Complex Systems. Theoretical arguments and experimental evidences are presented which show that such an electron exhibits characteristic properties of spatiotemporal complexities due to Self-Organized Criticality (SOC). This implies in particular that, conceptually and logically, it is neither possible nor meaningful to identify such an object with an ordinary particle, which by definition is something that has a fixed mass (size), a fixed lifetime, and a fixed structure. |
1207.3245 | Alexei P. Martynenko | A. P. Martynenko (Samara State U. and Samara State Aerospace U.) and
A. M. Trunin (Samara State Aerospace U.) | Relativistic corrections to double charmonium production in high energy
proton-proton interaction | 18 pages, 5 figures | null | 10.1103/PhysRevD.86.094003 | SSU-HEP-12/07 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | On the basis of pertubative QCD and the relativistic quark model we calculate
relativistic corrections to the process of pair $J/\psi$ production in
proton-proton collisions at LHC energy $\sqrt S=7$ TeV. Relativistic terms in
the production amplitude connected with the relative motion of heavy quarks and
the transformation law of the bound state wave functions to the reference frame
of moving $J/\psi$ mesons are taken into account. For the gluon and quark
propagators entering the amplitude we use a truncated expansion in relative
quark momenta up to the second order. Relativistic corrections to the quark
bound state wave functions are considered by means of the Breit-like potential.
It turns out that the examined effects decrease initial nonrelativistic cross
section more than two times. The final result lies below the experimental value
measured by LHCb.
| [
{
"created": "Fri, 13 Jul 2012 13:55:42 GMT",
"version": "v1"
}
] | 2013-05-30 | [
[
"Martynenko",
"A. P.",
"",
"Samara State U. and Samara State Aerospace U."
],
[
"Trunin",
"A. M.",
"",
"Samara State Aerospace U."
]
] | On the basis of pertubative QCD and the relativistic quark model we calculate relativistic corrections to the process of pair $J/\psi$ production in proton-proton collisions at LHC energy $\sqrt S=7$ TeV. Relativistic terms in the production amplitude connected with the relative motion of heavy quarks and the transformation law of the bound state wave functions to the reference frame of moving $J/\psi$ mesons are taken into account. For the gluon and quark propagators entering the amplitude we use a truncated expansion in relative quark momenta up to the second order. Relativistic corrections to the quark bound state wave functions are considered by means of the Breit-like potential. It turns out that the examined effects decrease initial nonrelativistic cross section more than two times. The final result lies below the experimental value measured by LHCb. |
0912.3149 | M. E. Carrington | M.E. Carrington and E. Kovalchuk | Next-to-Leading Order Transport Coefficients from the Four-Particle
Irreducible Effective Action | 24 pages, 18 figures. Added references and minor rewordings:
published version | Phys.Rev.D81:065017,2010 | 10.1103/PhysRevD.81.065017 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Transport coefficients can be obtained from 2-point correlators using the
Kubo formulae. It has been shown that the full leading order result for
electrical conductivity and (QCD) shear viscosity is contained in the re-summed
2-point function that is obtained from the 3-loop 3PI re-summed effective
action. The theory produces all leading order contributions without the
necessity for power counting, and in this sense it provides a natural framework
for the calculation. In this article we study the 4-loop 4PI effective action
for a scalar theory with cubic and quartic interactions in the presence of
spontaneous symmetry breaking. We obtain a set of integral equations that
determine the re-summed 2-point vertex function. A next-to-leading order
contribution to the viscosity could be obtained from this set of coupled
equations.
| [
{
"created": "Wed, 16 Dec 2009 14:34:24 GMT",
"version": "v1"
},
{
"created": "Sun, 7 Mar 2010 14:08:47 GMT",
"version": "v2"
}
] | 2010-04-29 | [
[
"Carrington",
"M. E.",
""
],
[
"Kovalchuk",
"E.",
""
]
] | Transport coefficients can be obtained from 2-point correlators using the Kubo formulae. It has been shown that the full leading order result for electrical conductivity and (QCD) shear viscosity is contained in the re-summed 2-point function that is obtained from the 3-loop 3PI re-summed effective action. The theory produces all leading order contributions without the necessity for power counting, and in this sense it provides a natural framework for the calculation. In this article we study the 4-loop 4PI effective action for a scalar theory with cubic and quartic interactions in the presence of spontaneous symmetry breaking. We obtain a set of integral equations that determine the re-summed 2-point vertex function. A next-to-leading order contribution to the viscosity could be obtained from this set of coupled equations. |
hep-ph/0611187 | Hai-Xia Zhang | S. S. Wu, H. B. Yao and Y. J. Yao (Center for Theoretical Physics and
School of Physics, JiLin University, Changchun, P.R.China) | Extension of Renormalizability | 9 pages, 3 figures | null | null | null | hep-ph | null | Arguments are provided which show that extension of renormalizability in
quantum field theory is possible. A dressed scheme for the perturbation
expansion is proposed. It is proven that in this scheme a nonrenormalizable
interaction becomes renormalizable in the restrictive sense, i.e. its
ultraviolet divergences can be cancelled by a finite number of counterterms
included in the Lagrangian. As an illustration, the renormalization of the
$\pi$-nucleon pseudovector interaction is discussed in some detail.
| [
{
"created": "Tue, 14 Nov 2006 13:54:03 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Wu",
"S. S.",
"",
"Center for Theoretical Physics and\n School of Physics, JiLin University, Changchun, P.R.China"
],
[
"Yao",
"H. B.",
"",
"Center for Theoretical Physics and\n School of Physics, JiLin University, Changchun, P.R.China"
],
[
"Yao",
"Y. J.",
"",
"Center for Theoretical Physics and\n School of Physics, JiLin University, Changchun, P.R.China"
]
] | Arguments are provided which show that extension of renormalizability in quantum field theory is possible. A dressed scheme for the perturbation expansion is proposed. It is proven that in this scheme a nonrenormalizable interaction becomes renormalizable in the restrictive sense, i.e. its ultraviolet divergences can be cancelled by a finite number of counterterms included in the Lagrangian. As an illustration, the renormalization of the $\pi$-nucleon pseudovector interaction is discussed in some detail. |
1207.5666 | York Schroder | Y. Schroder | A fresh look on three-loop sum-integrals | 19 pages | null | 10.1007/JHEP08(2012)095 | BI-TP 2012/29 | hep-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In order to prepare the ground for evaluating classes of three-loop
sum-integrals that are presently needed for thermodynamic observables, we take
a fresh and systematic look on the few known cases, and review their evaluation
in a unified way using coherent notation. We do this for three important cases
of massless bosonic three-loop vacuum sum-integrals that have been frequently
used in the literature, and aim for a streamlined exposition as compared to the
original evaluations. In passing, we speculate on options for generalization of
the computational techniques that have been employed.
| [
{
"created": "Tue, 24 Jul 2012 11:55:19 GMT",
"version": "v1"
}
] | 2015-06-05 | [
[
"Schroder",
"Y.",
""
]
] | In order to prepare the ground for evaluating classes of three-loop sum-integrals that are presently needed for thermodynamic observables, we take a fresh and systematic look on the few known cases, and review their evaluation in a unified way using coherent notation. We do this for three important cases of massless bosonic three-loop vacuum sum-integrals that have been frequently used in the literature, and aim for a streamlined exposition as compared to the original evaluations. In passing, we speculate on options for generalization of the computational techniques that have been employed. |
2205.07889 | Mohamed Jakha | S. Mouslih, M. Jakha, S. El Asri, S. Taj, B. Manaut, R. Benbrik and E
Siher | Laser-assisted charged Higgs boson decay in Two Higgs Doublet Model --
type II | 17 pages, 7 figures, 1 table | null | 10.1016/j.physletb.2022.137339 | null | hep-ph | http://creativecommons.org/licenses/by/4.0/ | In this paper, we investigate the charged Higgs boson decay in the context of
the type-II two-Higgs-doublet model in the presence of a circularly polarized
electromagnetic field of laser radiation. The calculations are performed by
adopting the Furry picture approach of non-perturbative interactions with the
external electromagnetic field. Using the method of exact solutions for charged
particles states in the presence of a circularly polarized electromagnetic wave
field and evaluating the $S$-matrix elements, an exact analytic expression is
derived for the decay width of leptonic, hadronic and bosonic decay modes. The
branching ratios of different decay modes with multiple photon emission and
absorption from the laser beam are analyzed and found to be dramatically
modified in the region of superstrong fields. The dependencies of the decay
width on the laser field strength and frequency are also examined. The results
obtained may be interesting for future experimental and theoretical
investigations.
| [
{
"created": "Mon, 16 May 2022 16:58:37 GMT",
"version": "v1"
}
] | 2022-09-14 | [
[
"Mouslih",
"S.",
""
],
[
"Jakha",
"M.",
""
],
[
"Asri",
"S. El",
""
],
[
"Taj",
"S.",
""
],
[
"Manaut",
"B.",
""
],
[
"Benbrik",
"R.",
""
],
[
"Siher",
"E",
""
]
] | In this paper, we investigate the charged Higgs boson decay in the context of the type-II two-Higgs-doublet model in the presence of a circularly polarized electromagnetic field of laser radiation. The calculations are performed by adopting the Furry picture approach of non-perturbative interactions with the external electromagnetic field. Using the method of exact solutions for charged particles states in the presence of a circularly polarized electromagnetic wave field and evaluating the $S$-matrix elements, an exact analytic expression is derived for the decay width of leptonic, hadronic and bosonic decay modes. The branching ratios of different decay modes with multiple photon emission and absorption from the laser beam are analyzed and found to be dramatically modified in the region of superstrong fields. The dependencies of the decay width on the laser field strength and frequency are also examined. The results obtained may be interesting for future experimental and theoretical investigations. |
hep-ph/9811247 | Gordon Ramsey | L. E. Gordon and G. P. Ramsey | Spin Structure of the Proton and Large p_T Processes in Polarized pp
Collisions | 34 pages, including 18 postscript figures, REVTeX | Phys.Rev.D59:074018,1999 | 10.1103/PhysRevD.59.074018 | null | hep-ph | null | QCD motivated polarized parton distributions, evolved directly in x-space,
are used to predict rates for prompt photon and Jet production at RHIC and
HERA-N center of mass energies. Various scenarios for the polarized gluon
distributions are considered and compared, and the possibility of using large
p_T processes in polarized pp collision experients to choose between them is
analyzed.
| [
{
"created": "Wed, 4 Nov 1998 21:42:49 GMT",
"version": "v1"
}
] | 2014-11-17 | [
[
"Gordon",
"L. E.",
""
],
[
"Ramsey",
"G. P.",
""
]
] | QCD motivated polarized parton distributions, evolved directly in x-space, are used to predict rates for prompt photon and Jet production at RHIC and HERA-N center of mass energies. Various scenarios for the polarized gluon distributions are considered and compared, and the possibility of using large p_T processes in polarized pp collision experients to choose between them is analyzed. |
0806.4036 | Aparajita Bhattacharya | B.Chakrabarti, A. Bhattachary, S. Mani | On Some properties of Di-hadronic states | 11 pages | Phys.Scripta 79:025103,2009 | 10.1088/0031-8949/79/02/025103 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The binding energies of di- hadronic states have been calculated assuming a
'molecular' interaction provided by the asymptotic expression of the residual
confined gluon exchange potential between the component hadrons in the system.
Meson- meson and meson- baryon states have been studied in detail and a mass
formula has been used to calculate total mass of the 'molecules'.
| [
{
"created": "Wed, 25 Jun 2008 07:35:53 GMT",
"version": "v1"
}
] | 2013-09-05 | [
[
"Chakrabarti",
"B.",
""
],
[
"Bhattachary",
"A.",
""
],
[
"Mani",
"S.",
""
]
] | The binding energies of di- hadronic states have been calculated assuming a 'molecular' interaction provided by the asymptotic expression of the residual confined gluon exchange potential between the component hadrons in the system. Meson- meson and meson- baryon states have been studied in detail and a mass formula has been used to calculate total mass of the 'molecules'. |
hep-ph/0512112 | Xinjian Wen | G.X. Peng, X.J.Wen, Y.D. Chen | New solutions for the color-flavor locked strangelets | 5 pages, 4 figures, Revtex4 style | Phys.Lett.B633:314-318,2006 | 10.1016/j.physletb.2005.11.081 | null | hep-ph | null | Recent publications rule out the negatively charged beta equilibrium
strangelets in ordinary phase, and the color-flavor locked (CFL) strangelets
are reported to be also positively charged. This letter presents new solutions
to the system equations where CFL strangelets are slightly negatively charged.
If the ratio of the square-root bag constant to the gap parameter is smaller
than 170 MeV, the CFL strangelets are more stable than iron and the normal
unpaired strangelets. For the same parameters, however, the positively charged
CFL strangelets are more stable.
| [
{
"created": "Fri, 9 Dec 2005 04:11:24 GMT",
"version": "v1"
}
] | 2014-11-18 | [
[
"Peng",
"G. X.",
""
],
[
"Wen",
"X. J.",
""
],
[
"Chen",
"Y. D.",
""
]
] | Recent publications rule out the negatively charged beta equilibrium strangelets in ordinary phase, and the color-flavor locked (CFL) strangelets are reported to be also positively charged. This letter presents new solutions to the system equations where CFL strangelets are slightly negatively charged. If the ratio of the square-root bag constant to the gap parameter is smaller than 170 MeV, the CFL strangelets are more stable than iron and the normal unpaired strangelets. For the same parameters, however, the positively charged CFL strangelets are more stable. |
hep-ph/0212195 | Xing ZhiZhong | Harald Fritzsch and Zhi-zhong Xing | Four-Zero Texture of Hermitian Quark Mass Matrices and Current
Experimental Tests | LaTex 9 pages | Phys.Lett.B555:63-70,2003 | 10.1016/S0370-2693(03)00048-0 | null | hep-ph | null | We show that the four-zero texture of Hermitian quark mass matrices can
survive current experimental tests: it is able to yield sufficiently large
predictions for the flavor mixing parameter $|V_{ub}/V_{cb}|$ and the
CP-violating parameter $\sin 2\beta$, without fine-tuning of the input values
of quark masses, provided the (2,2), (2,3) and (3,3) elements of up and down
mass matrices roughly satisfy a geometrical hierarchy. The successful relations
$|V_{us}| \approx \sqrt{m_u/m_c + m_d/m_s}$ and $|V_{td}/V_{ts}| \approx
\sqrt{m_d/m_s}$ obtained previously from the six-zero texture of Hermitian
quark mass matrices remain unchanged in the new ansatz.
| [
{
"created": "Fri, 13 Dec 2002 16:41:04 GMT",
"version": "v1"
}
] | 2010-11-23 | [
[
"Fritzsch",
"Harald",
""
],
[
"Xing",
"Zhi-zhong",
""
]
] | We show that the four-zero texture of Hermitian quark mass matrices can survive current experimental tests: it is able to yield sufficiently large predictions for the flavor mixing parameter $|V_{ub}/V_{cb}|$ and the CP-violating parameter $\sin 2\beta$, without fine-tuning of the input values of quark masses, provided the (2,2), (2,3) and (3,3) elements of up and down mass matrices roughly satisfy a geometrical hierarchy. The successful relations $|V_{us}| \approx \sqrt{m_u/m_c + m_d/m_s}$ and $|V_{td}/V_{ts}| \approx \sqrt{m_d/m_s}$ obtained previously from the six-zero texture of Hermitian quark mass matrices remain unchanged in the new ansatz. |
0906.2391 | Alexander Studenikin | I.Balantsev, Yu.Popov, A.Studenikin | Neutrino magnetic moment and neutrino energy quantization in rotating
media | 7 pagex in LaTex, to appear in Proceedings of the XXIII Recontres de
Physique de la Vallee D'Aoste on "Results and Perspectives in Particle
Physics" (La Thuile, Italy, March 1-7, 2009) | Nuovo Cim.C32N5-6:53-61,2009 | 10.1393/ncc/i2010-10539-7 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | After a brief discussion on neutrino electromagnetic properties, we consider
the problem of neutrino energy spectra in different media. It is shown that in
two particular cases (i.e., neutrino propagation in a) transversally moving
with increasing speed medium and b) rotating medium) neutrino energies are
quantized. These phenomena can be important for astrophysical applications, for
instance, for physics of rotating neutron stars.
| [
{
"created": "Fri, 12 Jun 2009 17:57:51 GMT",
"version": "v1"
}
] | 2010-09-27 | [
[
"Balantsev",
"I.",
""
],
[
"Popov",
"Yu.",
""
],
[
"Studenikin",
"A.",
""
]
] | After a brief discussion on neutrino electromagnetic properties, we consider the problem of neutrino energy spectra in different media. It is shown that in two particular cases (i.e., neutrino propagation in a) transversally moving with increasing speed medium and b) rotating medium) neutrino energies are quantized. These phenomena can be important for astrophysical applications, for instance, for physics of rotating neutron stars. |
1603.07232 | Andreas Krassnigg | A. Krassnigg, M. Gomez-Rocha, T. Hilger | Leptonic decays of D-wave vector quarkonia | 5 pages, 4 figures, 1 table, revised after reviewer comments; to
appear in the proceedings of the FAIRNESS2016 workshop | J. Phys. Conf. Ser. 742, 012032 (2016) | 10.1088/1742-6596/742/1/012032 | null | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We give a short and basic introduction to our covariant
Dyson-Schwinger-Bethe-Salpeter-equation approach using a rainbow-ladder
truncated model of QCD, in which we investigate the leptonic decay properties
of heavy quarkonium states in the pseudoscalar and vector channels. Comparing
the magnitudes of decay constants, we identify radial 1-- excitations in our
calculation with experimental excitations of J/\Psi and \Upsilon. Particular
attention is paid to those states regarded as D-wave states in the quark model.
We predict e+e- decay width of the \Upsilon(1^3D_1) and \Upsilon(2^3D_1) states
of the order of ca. 15 eV or more. We also provide a set of predictions for
decay constants of pseudoscalar radial excitations in heavy quarkonia.
| [
{
"created": "Wed, 23 Mar 2016 15:21:22 GMT",
"version": "v1"
},
{
"created": "Fri, 22 Apr 2016 08:58:55 GMT",
"version": "v2"
}
] | 2016-11-07 | [
[
"Krassnigg",
"A.",
""
],
[
"Gomez-Rocha",
"M.",
""
],
[
"Hilger",
"T.",
""
]
] | We give a short and basic introduction to our covariant Dyson-Schwinger-Bethe-Salpeter-equation approach using a rainbow-ladder truncated model of QCD, in which we investigate the leptonic decay properties of heavy quarkonium states in the pseudoscalar and vector channels. Comparing the magnitudes of decay constants, we identify radial 1-- excitations in our calculation with experimental excitations of J/\Psi and \Upsilon. Particular attention is paid to those states regarded as D-wave states in the quark model. We predict e+e- decay width of the \Upsilon(1^3D_1) and \Upsilon(2^3D_1) states of the order of ca. 15 eV or more. We also provide a set of predictions for decay constants of pseudoscalar radial excitations in heavy quarkonia. |
0801.0344 | Jae Yong Lee | Jae Yong Lee | Not T-parity but C-parity | 14 pages, 2 figures | null | null | KIAS-P07100 | hep-ph | null | We revisit the Littlest Higgs model with $T$-parity, and discover a $Z_2$
symmetry on collective symmetry. It is dubbed collective parity
($\EuScript{C}$-parity). We demonstrate that $T$-parity is consistent with
$\EuScript{C}$-parity. We further investigate the origin of the collective
symmetry in the context of composite Higgs and find a new path to the UV
complete theory of the model. In addition, we demonstrate that $T$-parity
violating processes naturally take place.
| [
{
"created": "Wed, 2 Jan 2008 06:42:23 GMT",
"version": "v1"
}
] | 2008-01-03 | [
[
"Lee",
"Jae Yong",
""
]
] | We revisit the Littlest Higgs model with $T$-parity, and discover a $Z_2$ symmetry on collective symmetry. It is dubbed collective parity ($\EuScript{C}$-parity). We demonstrate that $T$-parity is consistent with $\EuScript{C}$-parity. We further investigate the origin of the collective symmetry in the context of composite Higgs and find a new path to the UV complete theory of the model. In addition, we demonstrate that $T$-parity violating processes naturally take place. |
hep-ph/9608347 | Christian Weiss | M.K. Volkov (JINR Dubna) and C. Weiss (Ruhr-Univ. Bochum) | A chiral Lagrangian for excited pions | 19 pages, LaTeX, 3 Postscript figures included using epsf | Phys.Rev. D56 (1997) 221-229 | 10.1103/PhysRevD.56.221 | RUB-TPII-12/96 | hep-ph | null | We construct a chiral Lagrangian containing besides the usual pion field (pi)
also its first radial excitation (pi'). The Lagrangian is derived by
bosonization of a Nambu--Jona-Lasinio quark model with separable non-local
interactions, with form factors corresponding to 3-dimensional ground and
excited state wave functions. Chiral symmetry breaking is governed by the NJL
gap equation. The effective Lagrangian for pi- and pi'-mesons shows the
decoupling of the Goldstone pion and the vanishing of the pi' leptonic decay
constant, f_pi', in the chiral limit, as required by axial current
conservation. We derive the excited states' contribution to the axial current
of the model using Noether's theorem. For finite pion mass and pi' masses in
the range of 750 MeV -- 1300 MeV, f_pi' / f_pi is found to be of the order of 1
percent.
| [
{
"created": "Fri, 16 Aug 1996 13:49:57 GMT",
"version": "v1"
}
] | 2009-10-28 | [
[
"Volkov",
"M. K.",
"",
"JINR Dubna"
],
[
"Weiss",
"C.",
"",
"Ruhr-Univ. Bochum"
]
] | We construct a chiral Lagrangian containing besides the usual pion field (pi) also its first radial excitation (pi'). The Lagrangian is derived by bosonization of a Nambu--Jona-Lasinio quark model with separable non-local interactions, with form factors corresponding to 3-dimensional ground and excited state wave functions. Chiral symmetry breaking is governed by the NJL gap equation. The effective Lagrangian for pi- and pi'-mesons shows the decoupling of the Goldstone pion and the vanishing of the pi' leptonic decay constant, f_pi', in the chiral limit, as required by axial current conservation. We derive the excited states' contribution to the axial current of the model using Noether's theorem. For finite pion mass and pi' masses in the range of 750 MeV -- 1300 MeV, f_pi' / f_pi is found to be of the order of 1 percent. |
hep-ph/9506312 | null | K.C. Chou (CAS) and Yue-Liang Wu (OSU) | A Predictive Superunification $SO(10)\times \Delta_{48}(SU(3))\times
U(1)$ Model for Fermion Masses and Mixings | 9 pages, REVTeX, no figures, two tables i), The superpotentials in
eqs. (2) and (3) are simplified and the corresponding notations are redefined
below eq. (3); ii), one sentence in the paragraph below eq.(3) is extended to
: `Once ..., the resulting Yukawa coupling matrices at the GUT scale will be
automatically forced, due to the special features of $\Delta_{48}(SU(3))$, to
an interesting texture structure with four non-zero textures `33', `32', `22'
and `12' ...'. iii) "All other results and conclusions as well as predictions
are unchanged!!!" | null | null | CAS-HEP-T-95-06/001; OHSTPY-HEP-T-95-016 | hep-ph | null | Based on a few basic assumptions, a predictive supersymmetric grand
unification $G_{U}=SO(10)\times \Delta_{48}(SU(3))\times U(1)$ model is
proposed. Thus, all the observed 45 chiral fermions with additional 3
right-handed neutrinos are unified into an irreducible triplet 16-dimensional
spinor representation of $G_{U}$. Electroweak symmetry breaking naturally
requires two Higgs doublets which belong to a single 10 representation of
$SO(10)$. The model provides an unified description for all the Yukawa and
gauge couplings. With a given structure of the physical vacuum, the fermion
masses and mixings are predicted in terms of two basic parameters.
| [
{
"created": "Tue, 13 Jun 1995 14:21:26 GMT",
"version": "v1"
},
{
"created": "Tue, 27 Jun 1995 15:32:00 GMT",
"version": "v2"
}
] | 2008-02-03 | [
[
"Chou",
"K. C.",
"",
"CAS"
],
[
"Wu",
"Yue-Liang",
"",
"OSU"
]
] | Based on a few basic assumptions, a predictive supersymmetric grand unification $G_{U}=SO(10)\times \Delta_{48}(SU(3))\times U(1)$ model is proposed. Thus, all the observed 45 chiral fermions with additional 3 right-handed neutrinos are unified into an irreducible triplet 16-dimensional spinor representation of $G_{U}$. Electroweak symmetry breaking naturally requires two Higgs doublets which belong to a single 10 representation of $SO(10)$. The model provides an unified description for all the Yukawa and gauge couplings. With a given structure of the physical vacuum, the fermion masses and mixings are predicted in terms of two basic parameters. |
1406.2291 | Valentin V. Khoze | Valentin V. Khoze and Gunnar Ro | Dark matter monopoles, vectors and photons | 24 pages, 10 figures v2: Reference added; v3: minor typos corrected,
References added | null | 10.1007/JHEP10(2014)061 | IPPP/14/53, DCPT/14/106 | hep-ph astro-ph.CO hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In a secluded dark sector which is coupled to the Standard Model via a Higgs
portal interaction we arrange for the existence of 't Hooft-Polyakov magnetic
monopoles and study their implications for cosmology. We point out that a dark
sector which can accommodate stable monopoles will also contain massless dark
photons gamma' as well as charged massive vector bosons W'. The dark matter in
this scenario will be a combination of magnetically and electrically charged
species under the unbroken U(1) subgroup of the dark sector. We estimate the
cosmological production rate of monopoles and the rate of
monopole-anti-monopole annihilation and conclude that monopoles with masses of
few hundred TeV or greater, can produce sizeable contributions to the observed
dark matter relic density. We scan over the parameter space and compute the
relic density for monopoles and vector bosons. Turning to the dark photon
radiation, we compute their contribution to the measured density of
relativistic particles Neff and also apply observational constraints from the
Bullet cluster and other large scale galaxies on long-range interactions for
the self-interacting dark matter components made out of monopoles and out of
dark vector bosons. At scales relevant for dwarf galaxies we identify regions
on the parameter space where self-interacting monopole and vector dark mater
components can aid solving the core-cusp and the too-big-to-fail problems.
| [
{
"created": "Mon, 9 Jun 2014 19:27:08 GMT",
"version": "v1"
},
{
"created": "Tue, 10 Jun 2014 19:31:18 GMT",
"version": "v2"
},
{
"created": "Thu, 18 Feb 2016 12:04:18 GMT",
"version": "v3"
}
] | 2016-02-19 | [
[
"Khoze",
"Valentin V.",
""
],
[
"Ro",
"Gunnar",
""
]
] | In a secluded dark sector which is coupled to the Standard Model via a Higgs portal interaction we arrange for the existence of 't Hooft-Polyakov magnetic monopoles and study their implications for cosmology. We point out that a dark sector which can accommodate stable monopoles will also contain massless dark photons gamma' as well as charged massive vector bosons W'. The dark matter in this scenario will be a combination of magnetically and electrically charged species under the unbroken U(1) subgroup of the dark sector. We estimate the cosmological production rate of monopoles and the rate of monopole-anti-monopole annihilation and conclude that monopoles with masses of few hundred TeV or greater, can produce sizeable contributions to the observed dark matter relic density. We scan over the parameter space and compute the relic density for monopoles and vector bosons. Turning to the dark photon radiation, we compute their contribution to the measured density of relativistic particles Neff and also apply observational constraints from the Bullet cluster and other large scale galaxies on long-range interactions for the self-interacting dark matter components made out of monopoles and out of dark vector bosons. At scales relevant for dwarf galaxies we identify regions on the parameter space where self-interacting monopole and vector dark mater components can aid solving the core-cusp and the too-big-to-fail problems. |
hep-ph/0201305 | Fulvia De Fazio | P. Colangelo and F. De Fazio | On three-body $B^0 \to D^{*-} D^{(*)0} K^+$ decays and couplings of
heavy mesons to light pseudoscalar mesons | LaTex, 16 pages, 5 figures | Phys.Lett. B532 (2002) 193-201 | 10.1016/S0370-2693(02)01548-4 | null | hep-ph | null | We analyze the decay modes $B^0 \to D^{*-} D^0 K^+$ and $B^0 \to D^{*-}
D^{*0} K^+$ and, using the available experimental data, we find bounds for the
constants g and h describing the strong coupling of heavy mesons to light
pseudoscalar mesons. Both the decay channels are dominated by broad L=1 charm
resonances; the dominance is effective also in $B^0 \to D^{-} D^0 K^+$ and $B^0
\to D^{-} D^{*0} K^+$.
| [
{
"created": "Thu, 31 Jan 2002 16:06:45 GMT",
"version": "v1"
}
] | 2009-11-07 | [
[
"Colangelo",
"P.",
""
],
[
"De Fazio",
"F.",
""
]
] | We analyze the decay modes $B^0 \to D^{*-} D^0 K^+$ and $B^0 \to D^{*-} D^{*0} K^+$ and, using the available experimental data, we find bounds for the constants g and h describing the strong coupling of heavy mesons to light pseudoscalar mesons. Both the decay channels are dominated by broad L=1 charm resonances; the dominance is effective also in $B^0 \to D^{-} D^0 K^+$ and $B^0 \to D^{-} D^{*0} K^+$. |
1210.3531 | Milovan Vasilic | Branislav Sazdovi\'c and Milovan Vasili\'c | Oscillations of neutrino velocity | 17 pages, 5 figures | JHEP 03 (2013) 047 | 10.1007/JHEP03(2013)047 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this paper, we consider the problem of quantum measurement of neutrino
velocity. We show, that the well known neutrino flavor oscillations are always
accompanied by the oscillations of neutrino velocity. In particular, the
velocity of a freely moving neutrino is demonstrated to periodically exceed the
speed of light. Unfortunately, the superluminal effect turns out to be too
small to be experimentally detected. It is also shown that neutrino velocity
significantly depends on the energy, size and shape of the neutrino wave
packet. Owing to the big experimental error of the recent experiments, these
dependences remained unnoticeable. Finally, we have shown that the recent
claims that superluminal neutrinos should loose energy during their flight is
not true. Instead, our formula suggests the approximate conservation of energy
along neutrino trajectory. All these results have been obtained without
violation of special theory of relativity.
| [
{
"created": "Fri, 12 Oct 2012 14:32:28 GMT",
"version": "v1"
}
] | 2015-04-02 | [
[
"Sazdović",
"Branislav",
""
],
[
"Vasilić",
"Milovan",
""
]
] | In this paper, we consider the problem of quantum measurement of neutrino velocity. We show, that the well known neutrino flavor oscillations are always accompanied by the oscillations of neutrino velocity. In particular, the velocity of a freely moving neutrino is demonstrated to periodically exceed the speed of light. Unfortunately, the superluminal effect turns out to be too small to be experimentally detected. It is also shown that neutrino velocity significantly depends on the energy, size and shape of the neutrino wave packet. Owing to the big experimental error of the recent experiments, these dependences remained unnoticeable. Finally, we have shown that the recent claims that superluminal neutrinos should loose energy during their flight is not true. Instead, our formula suggests the approximate conservation of energy along neutrino trajectory. All these results have been obtained without violation of special theory of relativity. |
1206.6599 | Richard Williams | Helios Sanchis-Alepuz, Reinhard Alkofer, Richard Williams | Baryon properties from the covariant Faddeev equation | 6 pages, 2 figures, contribution to the proceedings of the Sixth
International Conference on Quarks and Nuclear Physics (QNP2012), April
16-20, 2012, Palaiseau, France | PoS QNP2012 (2012) 112 | null | null | hep-ph hep-lat nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | A calculation of the masses and electromagnetic properties of the Delta and
Omega baryon together with their evolution with the current quark mass is
presented. Hereby a generalized Bethe-Salpeter approach with the interaction
truncated to a dressed one-gluon exchange is employed. The model dependence is
explored by investigating two forms for the dressed gluon exchange.
| [
{
"created": "Thu, 28 Jun 2012 09:09:10 GMT",
"version": "v1"
}
] | 2012-07-03 | [
[
"Sanchis-Alepuz",
"Helios",
""
],
[
"Alkofer",
"Reinhard",
""
],
[
"Williams",
"Richard",
""
]
] | A calculation of the masses and electromagnetic properties of the Delta and Omega baryon together with their evolution with the current quark mass is presented. Hereby a generalized Bethe-Salpeter approach with the interaction truncated to a dressed one-gluon exchange is employed. The model dependence is explored by investigating two forms for the dressed gluon exchange. |
2209.07241 | Sabarnya Mitra | Sabarnya Mitra, Prasad Hegde, Christian Schmidt | A new way of determining the Lattice QCD equation of state at a finite
chemical potential | 9 pages, 8 figures, Contribution to The 39th International Symposium
on Lattice Field Theory (Lattice 2022), minor changes, 2 new references added | PoS LATTICE2022 (2023) 153 | 10.22323/1.430.0153 | null | hep-ph hep-lat nucl-ex nucl-th | http://creativecommons.org/licenses/by/4.0/ | The Taylor expansion of thermodynamic observables at a finite baryon chemical
potential $\mu_B$ is an oft-used method to circumvent the well-known sign
problem of Lattice QCD. Owing to the associated difficulty and limitations of
precision in calculating these high-ordered Taylor coefficients, it becomes
essential to look for various resummation schemes which can mitigate the
computational cost, besides providing trustworthy estimates of different
thermodynamic observables. Recently, a way to exponentially resum the
contribution of the first $N$ charge density correlation functions
$D_1,\dots,D_N$ to the Taylor series to all orders in $\mu_B$ was proposed in
Phys. Rev. Lett. 128, 2, 022001 (2022). Since the correlation functions $D_n$
are calculated stochastically using estimates from different random volume
sources, the resummation formulation gets affected by the biased estimates.
These estimates can become very drastic and can radically misdirect the
calculations for large values of $N$ and $\mu$ and also for observables which
are higher order $\mu$ derivatives of free energy, specially at lower
temperatures. In this work, we present a cumulant expansion procedure that
allows to investigate and regulate these biased estimates at different orders
in $\mu$. We find that the unbiased estimates in the cumulant expansion can
truly capture the genuine higher-order stochastic fluctuations of the higher
order correlation functions, which got suppressed by the exponential
resummation formulation. Finally, we discover an unbiased formalism of the
exponential resummation, which when expanded in a series, can exactly reproduce
the Taylor series upto a desired power in $\mu$. We are also able to regain the
knowledge of reweighting factor and many other important properties of the
partition function, which got entirely lost through the implementation of
cumulant expansion scheme.
| [
{
"created": "Thu, 15 Sep 2022 12:20:17 GMT",
"version": "v1"
},
{
"created": "Mon, 26 Sep 2022 12:47:41 GMT",
"version": "v2"
}
] | 2023-02-14 | [
[
"Mitra",
"Sabarnya",
""
],
[
"Hegde",
"Prasad",
""
],
[
"Schmidt",
"Christian",
""
]
] | The Taylor expansion of thermodynamic observables at a finite baryon chemical potential $\mu_B$ is an oft-used method to circumvent the well-known sign problem of Lattice QCD. Owing to the associated difficulty and limitations of precision in calculating these high-ordered Taylor coefficients, it becomes essential to look for various resummation schemes which can mitigate the computational cost, besides providing trustworthy estimates of different thermodynamic observables. Recently, a way to exponentially resum the contribution of the first $N$ charge density correlation functions $D_1,\dots,D_N$ to the Taylor series to all orders in $\mu_B$ was proposed in Phys. Rev. Lett. 128, 2, 022001 (2022). Since the correlation functions $D_n$ are calculated stochastically using estimates from different random volume sources, the resummation formulation gets affected by the biased estimates. These estimates can become very drastic and can radically misdirect the calculations for large values of $N$ and $\mu$ and also for observables which are higher order $\mu$ derivatives of free energy, specially at lower temperatures. In this work, we present a cumulant expansion procedure that allows to investigate and regulate these biased estimates at different orders in $\mu$. We find that the unbiased estimates in the cumulant expansion can truly capture the genuine higher-order stochastic fluctuations of the higher order correlation functions, which got suppressed by the exponential resummation formulation. Finally, we discover an unbiased formalism of the exponential resummation, which when expanded in a series, can exactly reproduce the Taylor series upto a desired power in $\mu$. We are also able to regain the knowledge of reweighting factor and many other important properties of the partition function, which got entirely lost through the implementation of cumulant expansion scheme. |
hep-ph/9312259 | Gianpiero Mangano | G. Mangano, G. Miele and G. Migliore | Quantum statistical effects on parton distribution scaling behaviour | 12 pages; latex; FERMILAB-Pub-93/380-A | null | null | null | hep-ph | null | Starting from the old idea that Fermi statistics for quarks play a
fundamental role to explain some features of hadron structure, we study the
modification of the scaling behaviour of parton distributions due to quantum
statistical effects. In particular, by following an interesting formal analogy
which holds between the Altarelli-Parisi evolution equations, in leading-log
approximation, and a set of Boltzmann equations, we generalize the evolution
equations to take into account Pauli exclusion principle and gluon induced
emission.
| [
{
"created": "Fri, 10 Dec 1993 10:31:55 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Mangano",
"G.",
""
],
[
"Miele",
"G.",
""
],
[
"Migliore",
"G.",
""
]
] | Starting from the old idea that Fermi statistics for quarks play a fundamental role to explain some features of hadron structure, we study the modification of the scaling behaviour of parton distributions due to quantum statistical effects. In particular, by following an interesting formal analogy which holds between the Altarelli-Parisi evolution equations, in leading-log approximation, and a set of Boltzmann equations, we generalize the evolution equations to take into account Pauli exclusion principle and gluon induced emission. |
2208.08747 | Markus Risse | Markus Risse | Using ultra-high energy cosmic rays and air showers to test Lorentz
invariance within modified Maxwell theory | Presented at the Ninth Meeting on CPT and Lorentz Symmetry,
Bloomington, Indiana, May 17-26, 2022 | null | null | null | hep-ph astro-ph.HE | http://creativecommons.org/licenses/by/4.0/ | Cosmic rays and air showers at ultra-high energy are unique tools to test the
validity of Lorentz invariance. A brief overview is given on such tests
focusing on isotropic, non-birefringent Lorentz violation (LV) in the photon
sector. Based on the apparent absence of vacuum Cherenkov radiation and photon
decay, the LV parameter $\kappa$ is bound to $-0.6 \cdot 10^{-20} < \kappa < 6
\cdot 10^{-20}$ (98\% CL). We report an updated limit from cosmic-ray photon
observations and preliminary results on testing vacuum Cherenkov radiation in
air showers.
| [
{
"created": "Thu, 18 Aug 2022 10:05:29 GMT",
"version": "v1"
}
] | 2022-08-19 | [
[
"Risse",
"Markus",
""
]
] | Cosmic rays and air showers at ultra-high energy are unique tools to test the validity of Lorentz invariance. A brief overview is given on such tests focusing on isotropic, non-birefringent Lorentz violation (LV) in the photon sector. Based on the apparent absence of vacuum Cherenkov radiation and photon decay, the LV parameter $\kappa$ is bound to $-0.6 \cdot 10^{-20} < \kappa < 6 \cdot 10^{-20}$ (98\% CL). We report an updated limit from cosmic-ray photon observations and preliminary results on testing vacuum Cherenkov radiation in air showers. |
hep-ph/0605154 | Sebastian Sapeta | S.Sapeta | DGLAP improved saturation model with heavy flavours | 4 pages, 2 figures; Talk presented at the 41th Rencontres de Moriond
on QCD and High Energy Hadronic Interactions, La Thuile, Italy, March 18-25,
2006 | null | null | null | hep-ph | null | The DGLAP improved saturation model of Bartels, Golec and Kowalski is
supplemented by the contribution from the heavy quarks: charm and beauty. It is
shown to give good description of both the total proton structure function F2
and, as a prediction, the heavy quarks contribution F2c and F2b. The reasonable
agreement for the longitudinal and diffractive structure functions is also
found.
| [
{
"created": "Sat, 13 May 2006 10:17:07 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Sapeta",
"S.",
""
]
] | The DGLAP improved saturation model of Bartels, Golec and Kowalski is supplemented by the contribution from the heavy quarks: charm and beauty. It is shown to give good description of both the total proton structure function F2 and, as a prediction, the heavy quarks contribution F2c and F2b. The reasonable agreement for the longitudinal and diffractive structure functions is also found. |
hep-ph/9607211 | Ken Williams | K.Williams | Revisiting the Eichten - Feinberg - Gromes Q \bar{Q} Spin-Orbit
Interaction | Latex, 22 pages (added appendix) | null | null | null | hep-ph | null | Invariant and covariant forms of the quark-antiquark interaction derived by
the method of Eichten and Feinberg are considered. Relations between the
various terms imposed by Lorentz transformation constraints, here called Gromes
relations, are found to exist in neither case. Details of the Gromes relation
proper are reconsidered and inconsistencies found that lead to a violation of
covariance.
| [
{
"created": "Mon, 1 Jul 1996 20:05:31 GMT",
"version": "v1"
},
{
"created": "Fri, 17 Dec 1999 15:55:39 GMT",
"version": "v2"
}
] | 2008-02-03 | [
[
"Williams",
"K.",
""
]
] | Invariant and covariant forms of the quark-antiquark interaction derived by the method of Eichten and Feinberg are considered. Relations between the various terms imposed by Lorentz transformation constraints, here called Gromes relations, are found to exist in neither case. Details of the Gromes relation proper are reconsidered and inconsistencies found that lead to a violation of covariance. |
2003.04157 | Simon May | Simon May (Westf\"alische Wilhelms-Universit\"at M\"unster) | Minimal dark matter models with radiative neutrino masses: From
Lagrangians to observables | 226 pages, 32 figures; master's thesis at Westf\"alische
Wilhelms-Universit\"at M\"unster | null | null | null | hep-ph astro-ph.CO | http://creativecommons.org/licenses/by-sa/4.0/ | In this master's thesis, the minimal dark matter models with radiative
neutrino masses introduced in arXiv:1308.3655 are examined both in general and,
using the model T1-3-B ($\alpha = 0$) as a representative, in more detail. In
the process, it is both shown how such models are built and a numerical
analysis tool chain is established, automating as many steps as possible from
the very beginning (deriving the Lagrangian from a given field content) to the
very end (calculating observables such as the dark matter relic density, the
direct detection cross section and the neutrino masses and mixing matrices).
As an important result in laying out the mathematical groundwork, a
convention for representations of SU(2) is established which, in this form, is
not found in previous works. Another major result is the development of the
program minimal-lagrangians, whose capabilities are described in the thesis. It
is of great use both for the construction of Lagrangians for new models as well
their verification or quick surveys. minimal-lagrangians can be applied to any
model within the class it is designed to handle, extending its utility far
beyond a one-time result that is only obtained for a single model.
Finally, the first steps in the analysis of the model T1-3-B ($\alpha = 0$)
are taken. It is shown that the model can reproduce both the singlet-doublet
fermion dark matter model and the inert triplet model in the appropriate
limits. Moreover, the neutrino mass matrix is found and it is demonstrated that
the model can accommodate current constraints on the neutrino masses. Lastly,
the behavior of the dark matter relic density as it depends on the parameter
responsible for the generation of neutrino masses is investigated.
Further in-depth study of the model T1-3-B ($\alpha = 0$) was performed in a
separate publication (arXiv:1812.11133).
| [
{
"created": "Mon, 9 Mar 2020 14:05:20 GMT",
"version": "v1"
}
] | 2020-03-10 | [
[
"May",
"Simon",
"",
"Westfälische Wilhelms-Universität Münster"
]
] | In this master's thesis, the minimal dark matter models with radiative neutrino masses introduced in arXiv:1308.3655 are examined both in general and, using the model T1-3-B ($\alpha = 0$) as a representative, in more detail. In the process, it is both shown how such models are built and a numerical analysis tool chain is established, automating as many steps as possible from the very beginning (deriving the Lagrangian from a given field content) to the very end (calculating observables such as the dark matter relic density, the direct detection cross section and the neutrino masses and mixing matrices). As an important result in laying out the mathematical groundwork, a convention for representations of SU(2) is established which, in this form, is not found in previous works. Another major result is the development of the program minimal-lagrangians, whose capabilities are described in the thesis. It is of great use both for the construction of Lagrangians for new models as well their verification or quick surveys. minimal-lagrangians can be applied to any model within the class it is designed to handle, extending its utility far beyond a one-time result that is only obtained for a single model. Finally, the first steps in the analysis of the model T1-3-B ($\alpha = 0$) are taken. It is shown that the model can reproduce both the singlet-doublet fermion dark matter model and the inert triplet model in the appropriate limits. Moreover, the neutrino mass matrix is found and it is demonstrated that the model can accommodate current constraints on the neutrino masses. Lastly, the behavior of the dark matter relic density as it depends on the parameter responsible for the generation of neutrino masses is investigated. Further in-depth study of the model T1-3-B ($\alpha = 0$) was performed in a separate publication (arXiv:1812.11133). |
2405.02415 | Thomas Steingasser | Thomas Steingasser | Higgs criticality in and beyond the Standard Model | 24 pages, Proceedings of the "Workshop on the Standard Model and
Beyond", Corfu Summer Institute, 2023 (CORFU2023-SM) | null | null | MIT-CTP/5717 | hep-ph astro-ph.CO hep-th | http://creativecommons.org/licenses/by/4.0/ | The properties of the Higgs potential are determined by three parameters: the
mass parameter, the quartic self-coupling, and a constant term. Remarkably, all
three of these parameters seem subject to a significant amount of fine-tuning.
All these tunings can be seen as their corresponding parameters being close to
critical values marking quantum phase transitions. While such behavior is
surprising from a conventional particle physics perspective, it is a common
feature of dynamical systems. This has motivated the conjecture that the values
of the Higgs' parameters are the result of some dynamical mechanism. This
possibility suggests the construction of mechanisms dynamically choosing sets
of Higgs parameters. In these notes, I discuss a complementary approach. Taking
seriously that such a mechanism could exist in nature, it is plausible to
assume that it also influences Beyond-Standard-Model physics. This suggests
considering near-criticality in any model of interest and investigating its
consequences more generally, in particular independent of a concrete mechanism
responsible for it. I first explain what it means for the parameters of the
Higgs potential to be near-critical. This includes a discussion of the recently
discovered "metastability bound" on the Higgs mass, which can be understood
through a critical point. I then review two concrete examples of mechanisms in
which the parameters of the Higgs potential are dynamically driven towards
critical values. These mechanisms also serve as an important proof on concept
for the feasibility of the assumptions at the foundation of these notes. Using
a simple example for concreteness, the final part of these notes then
explicitly demonstrates how to approach a given model in the light of the
near-criticality conjecture.
| [
{
"created": "Fri, 3 May 2024 18:16:36 GMT",
"version": "v1"
}
] | 2024-05-07 | [
[
"Steingasser",
"Thomas",
""
]
] | The properties of the Higgs potential are determined by three parameters: the mass parameter, the quartic self-coupling, and a constant term. Remarkably, all three of these parameters seem subject to a significant amount of fine-tuning. All these tunings can be seen as their corresponding parameters being close to critical values marking quantum phase transitions. While such behavior is surprising from a conventional particle physics perspective, it is a common feature of dynamical systems. This has motivated the conjecture that the values of the Higgs' parameters are the result of some dynamical mechanism. This possibility suggests the construction of mechanisms dynamically choosing sets of Higgs parameters. In these notes, I discuss a complementary approach. Taking seriously that such a mechanism could exist in nature, it is plausible to assume that it also influences Beyond-Standard-Model physics. This suggests considering near-criticality in any model of interest and investigating its consequences more generally, in particular independent of a concrete mechanism responsible for it. I first explain what it means for the parameters of the Higgs potential to be near-critical. This includes a discussion of the recently discovered "metastability bound" on the Higgs mass, which can be understood through a critical point. I then review two concrete examples of mechanisms in which the parameters of the Higgs potential are dynamically driven towards critical values. These mechanisms also serve as an important proof on concept for the feasibility of the assumptions at the foundation of these notes. Using a simple example for concreteness, the final part of these notes then explicitly demonstrates how to approach a given model in the light of the near-criticality conjecture. |
1407.3192 | Juan Jose Sanz-Cillero | P. Roig, J.J. Sanz-Cillero | Assessing the accuracy of the Brodsky-Lepage prediction | 4 pages. Proceedings of the talk given at the 17th International
Conference on Quantum Chromodynamics (QCD 14), 30 Jun-04 Jul 2014,
Montpellier, France. To be published at Nucl.Phys.Proc.Suppl | null | null | FTUAM-14-26, IFT-UAM/CSIC-14-064 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We show that a consistent set of short-distance conditions on the
odd-intrinsic parity resonance chiral Lagrangian couplings can be derived in
the large-$N_C$ limit and the single resonance approximation. These constraints
are satisfied both by the VVP Green function and all its associated
form-factors. Moreover, they are in agreement with earlier results found in the
normal parity sector, which further supports the overall consistency of the
approach. Here we take a new perspective and examine the consequences of these
high-energy relations on the precise coefficient of the $1/Q^2$-term of meson
form-factors, which rules their asymptotic behavior. In particular, we show
that the coefficient derived using our consistent set of short-distance
constraints is in remarkable accordance with the Brodsky-Lepage prediction,
being alternative results for these coefficients disfavored.
| [
{
"created": "Fri, 11 Jul 2014 15:07:08 GMT",
"version": "v1"
}
] | 2014-07-14 | [
[
"Roig",
"P.",
""
],
[
"Sanz-Cillero",
"J. J.",
""
]
] | We show that a consistent set of short-distance conditions on the odd-intrinsic parity resonance chiral Lagrangian couplings can be derived in the large-$N_C$ limit and the single resonance approximation. These constraints are satisfied both by the VVP Green function and all its associated form-factors. Moreover, they are in agreement with earlier results found in the normal parity sector, which further supports the overall consistency of the approach. Here we take a new perspective and examine the consequences of these high-energy relations on the precise coefficient of the $1/Q^2$-term of meson form-factors, which rules their asymptotic behavior. In particular, we show that the coefficient derived using our consistent set of short-distance constraints is in remarkable accordance with the Brodsky-Lepage prediction, being alternative results for these coefficients disfavored. |
hep-ph/0506109 | Celso C. Nishi | C. C. Nishi | First quantized approaches to neutrino oscillations and second
quantization | version accepted for publication | Phys.Rev. D73 (2006) 053013 | 10.1103/PhysRevD.73.053013 | null | hep-ph | null | Neutrino oscillations are treated from the point of view of relativistic
first quantized theories and compared to second quantized treatments. Within
first quantized theories, general oscillation probabilities can be found for
Dirac fermions and charged spin 0 bosons. A clear modification in the
oscillation formulas can be obtained and its origin is elucidated and confirmed
to be inevitable from completeness and causality requirements. The left-handed
nature of created and detected neutrinos can also be implemented in the first
quantized Dirac theory in presence of mixing; the probability loss due to the
changing of initially left-handed neutrinos to the undetected right-handed
neutrinos can be obtained in analytic form. Concerning second quantized
approaches, it is shown in a calculation using virtual neutrino propagation
that both neutrinos and antineutrinos may also contribute as intermediate
particles. The sign of the contributing neutrino energy may have to be chosen
explicitly without being automatic in the formalism. At last, a simple second
quantized description of the flavor oscillation phenomenon is devised. In this
description there is no interference terms between positive and negative
components, but it still gives simple normalized oscillation probabilities. A
new effect appearing in this context is an inevitable but tiny violation of the
initial flavor of neutrinos. The probability loss due to the conversion of
left-handed neutrinos to right-handed neutrinos is also presented.
| [
{
"created": "Sat, 11 Jun 2005 06:33:46 GMT",
"version": "v1"
},
{
"created": "Tue, 13 Sep 2005 03:41:08 GMT",
"version": "v2"
},
{
"created": "Tue, 4 Apr 2006 12:40:48 GMT",
"version": "v3"
}
] | 2009-11-11 | [
[
"Nishi",
"C. C.",
""
]
] | Neutrino oscillations are treated from the point of view of relativistic first quantized theories and compared to second quantized treatments. Within first quantized theories, general oscillation probabilities can be found for Dirac fermions and charged spin 0 bosons. A clear modification in the oscillation formulas can be obtained and its origin is elucidated and confirmed to be inevitable from completeness and causality requirements. The left-handed nature of created and detected neutrinos can also be implemented in the first quantized Dirac theory in presence of mixing; the probability loss due to the changing of initially left-handed neutrinos to the undetected right-handed neutrinos can be obtained in analytic form. Concerning second quantized approaches, it is shown in a calculation using virtual neutrino propagation that both neutrinos and antineutrinos may also contribute as intermediate particles. The sign of the contributing neutrino energy may have to be chosen explicitly without being automatic in the formalism. At last, a simple second quantized description of the flavor oscillation phenomenon is devised. In this description there is no interference terms between positive and negative components, but it still gives simple normalized oscillation probabilities. A new effect appearing in this context is an inevitable but tiny violation of the initial flavor of neutrinos. The probability loss due to the conversion of left-handed neutrinos to right-handed neutrinos is also presented. |
hep-ph/9806202 | Ram Brustein | Ram Brustein, Merav Hadad | Dark Matter Axions in Models of String Cosmology | 11 pages, no figures, revtex | Phys.Lett. B442 (1998) 74-81 | 10.1016/S0370-2693(98)01206-4 | BGU-PH-98/05, TAUP-2486-98 | hep-ph astro-ph hep-th | null | Axions are produced during a period of dilaton-driven inflation by
amplification of quantum fluctuations. We show that for some range of string
cosmology parameters and some range of axion masses, primordial axions may
constitute a large fraction of the present energy density in the universe in
the form of cold dark matter. Due to the periodic nature of the axion potential
energy density fluctuations are strongly suppressed. The spectrum of primordial
axions is not thermal, allowing a small fraction of the axions to remain
relativistic until quite late.
| [
{
"created": "Sat, 30 May 1998 10:39:07 GMT",
"version": "v1"
}
] | 2009-10-31 | [
[
"Brustein",
"Ram",
""
],
[
"Hadad",
"Merav",
""
]
] | Axions are produced during a period of dilaton-driven inflation by amplification of quantum fluctuations. We show that for some range of string cosmology parameters and some range of axion masses, primordial axions may constitute a large fraction of the present energy density in the universe in the form of cold dark matter. Due to the periodic nature of the axion potential energy density fluctuations are strongly suppressed. The spectrum of primordial axions is not thermal, allowing a small fraction of the axions to remain relativistic until quite late. |
hep-ph/0208100 | Wei Min Yang | Wei Min Yang and Dong Sheng Du | Associated production of a Higgs boson with tau sleptons in the CP
violating MSSM at future e^+ e^- colliders | 14 pages, 5 figures, LaTex2e. Figures updated with new calculation
results, and references added | Commun.Theor.Phys. 40 (2003) 85-90 | null | null | hep-ph | null | We investigate the production of the lightest neutral Higgs boson in
association with tau sleptons in the CP violating minimal supersymmetric
standard model (MSSM) at future high-energy $e^{+}e^{-}$ linear colliders. In
parameter space of the constrained MSSM, the production cross section of
$e^{+}e^{-}\to h^0\widetilde{\tau}^+_1\widetilde{\tau}^-_1$ can be very
substantial at high energies. This process would provide a new production
mechanism of neutral Higgs bosons and open a window to probe the Higgs-stau
coupling and some soft supersymmetric breaking parameters at next linear
colliders.
| [
{
"created": "Sat, 10 Aug 2002 02:27:26 GMT",
"version": "v1"
},
{
"created": "Wed, 21 Aug 2002 16:18:38 GMT",
"version": "v2"
},
{
"created": "Fri, 6 Sep 2002 08:17:56 GMT",
"version": "v3"
}
] | 2014-01-17 | [
[
"Yang",
"Wei Min",
""
],
[
"Du",
"Dong Sheng",
""
]
] | We investigate the production of the lightest neutral Higgs boson in association with tau sleptons in the CP violating minimal supersymmetric standard model (MSSM) at future high-energy $e^{+}e^{-}$ linear colliders. In parameter space of the constrained MSSM, the production cross section of $e^{+}e^{-}\to h^0\widetilde{\tau}^+_1\widetilde{\tau}^-_1$ can be very substantial at high energies. This process would provide a new production mechanism of neutral Higgs bosons and open a window to probe the Higgs-stau coupling and some soft supersymmetric breaking parameters at next linear colliders. |
1601.03973 | Keith Thrasher | Marc Sher and Keith Thrasher | Flavor Changing Leptonic Decays of Heavy Higgs Bosons | 7 pages, 2 figures, additional references added, version to be
published in Physical Review D | Phys. Rev. D 93, 055021 (2016) | 10.1103/PhysRevD.93.055021 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | CMS has reported indications (2.4\sigma) of the decay of the Higgs boson into
\mu\tau. The simplest explanation for such a decay would be a general Two Higgs
Doublet Model (2HDM). In this case, one would expect the heavy neutral Higgs
bosons, H and A, to also decay in a similar manner. We study two specific
models. The first is the type III 2HDM, and the second is a 2HDM, originally
proposed by Branco et al., in which all flavor-changing neutral processes are
given by the weak mixing matrix. In the latter model, since mixing between the
second and third generations in the lepton sector is large, flavor-changing
interactions are large. In this model it is found that the decays of H and A to
\mu\tau can be as high as 60 percent. This work has nothing to do with the 750
GeV diphoton resonance.
| [
{
"created": "Fri, 15 Jan 2016 15:49:23 GMT",
"version": "v1"
},
{
"created": "Thu, 21 Jan 2016 14:21:55 GMT",
"version": "v2"
},
{
"created": "Wed, 24 Feb 2016 18:38:23 GMT",
"version": "v3"
}
] | 2016-03-23 | [
[
"Sher",
"Marc",
""
],
[
"Thrasher",
"Keith",
""
]
] | CMS has reported indications (2.4\sigma) of the decay of the Higgs boson into \mu\tau. The simplest explanation for such a decay would be a general Two Higgs Doublet Model (2HDM). In this case, one would expect the heavy neutral Higgs bosons, H and A, to also decay in a similar manner. We study two specific models. The first is the type III 2HDM, and the second is a 2HDM, originally proposed by Branco et al., in which all flavor-changing neutral processes are given by the weak mixing matrix. In the latter model, since mixing between the second and third generations in the lepton sector is large, flavor-changing interactions are large. In this model it is found that the decays of H and A to \mu\tau can be as high as 60 percent. This work has nothing to do with the 750 GeV diphoton resonance. |
1806.10854 | Ramni Gupta Dr | Rohni Sharma and Ramni Gupta | Scaling Properties of Multiplicity Fluctuations in the AMPT Model | 6 pages, 5 figures | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | From the events generated from the MC code of a multi-phase transport (AMPT)
model with string melting, the properties of multiplicity fluctuations of
charged particles in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=\rm{~2.76
\,TeV}$ are studied. Normalized factorial moments, $F_{q}$, of spatial
distributions of the particles have been determined in the framework of
intermittency. Those moments are found in some kinematic regions to exhibit
scaling behavior at small bin sizes, but not in most regions. However, in
relating $F_{q}$ to $F_{2}$ scaling behavior is found in nearly all regions.
The corresponding scaling exponents, $\nu$, determined in the low transverse
momentum ($p_{\rm{T}}$) region $\le$ 1.0 GeV/c are observed to be independent
of the $p_{\rm{T}}$ bin position and width. The value of $\nu$ is found to be
larger than 1.304, which is the value that characterizes the Ginzburg-Landau
type second order phase transition. Thus there is no known signature for phase
transition in the AMPT model. This study demonstrates that, for the system
under investigation, the method of analysis is effective in extracting features
that are relevant to the question of whether the dynamical processes leading
phase transition are there or not.
| [
{
"created": "Thu, 28 Jun 2018 09:45:17 GMT",
"version": "v1"
},
{
"created": "Sat, 30 Jun 2018 02:12:01 GMT",
"version": "v2"
},
{
"created": "Mon, 29 Oct 2018 19:01:07 GMT",
"version": "v3"
}
] | 2018-10-31 | [
[
"Sharma",
"Rohni",
""
],
[
"Gupta",
"Ramni",
""
]
] | From the events generated from the MC code of a multi-phase transport (AMPT) model with string melting, the properties of multiplicity fluctuations of charged particles in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=\rm{~2.76 \,TeV}$ are studied. Normalized factorial moments, $F_{q}$, of spatial distributions of the particles have been determined in the framework of intermittency. Those moments are found in some kinematic regions to exhibit scaling behavior at small bin sizes, but not in most regions. However, in relating $F_{q}$ to $F_{2}$ scaling behavior is found in nearly all regions. The corresponding scaling exponents, $\nu$, determined in the low transverse momentum ($p_{\rm{T}}$) region $\le$ 1.0 GeV/c are observed to be independent of the $p_{\rm{T}}$ bin position and width. The value of $\nu$ is found to be larger than 1.304, which is the value that characterizes the Ginzburg-Landau type second order phase transition. Thus there is no known signature for phase transition in the AMPT model. This study demonstrates that, for the system under investigation, the method of analysis is effective in extracting features that are relevant to the question of whether the dynamical processes leading phase transition are there or not. |
2403.17614 | Davide Iacobacci | Alessandra D'Alise, Giuseppe Fabiano, Domenico Frattulillo, Davide
Iacobacci, Francesco Sannino, Pietro Santorelli, Natascia Vignaroli | New Physics Pathways from B Processes | 39 pages, 5 figures | null | null | null | hep-ph hep-th | http://creativecommons.org/licenses/by/4.0/ | We re-consider recent measures of $R_{K}$ and $R_{K^*}$, now compatible with
the Standard Model expectations, as well as the results for the process
$\text{BR}(B_s \rightarrow \mu^+ \mu^-)$ alongside earlier determinations of
$R_{D^{(\ast)}}$ and $\text{BR}(B_c \rightarrow \tau \nu)$. We provide analytic
constraints on the associated Wilson coefficients in both the $b \to s$ and the
$b \to c$ sectors. These allow us to estimate the scale of potential New
Physics for generic extensions of the Standard Model. We then use the results
to constrain the leptoquark landscape.
| [
{
"created": "Tue, 26 Mar 2024 11:48:23 GMT",
"version": "v1"
}
] | 2024-03-27 | [
[
"D'Alise",
"Alessandra",
""
],
[
"Fabiano",
"Giuseppe",
""
],
[
"Frattulillo",
"Domenico",
""
],
[
"Iacobacci",
"Davide",
""
],
[
"Sannino",
"Francesco",
""
],
[
"Santorelli",
"Pietro",
""
],
[
"Vignaroli",
"Natascia",
""
]
] | We re-consider recent measures of $R_{K}$ and $R_{K^*}$, now compatible with the Standard Model expectations, as well as the results for the process $\text{BR}(B_s \rightarrow \mu^+ \mu^-)$ alongside earlier determinations of $R_{D^{(\ast)}}$ and $\text{BR}(B_c \rightarrow \tau \nu)$. We provide analytic constraints on the associated Wilson coefficients in both the $b \to s$ and the $b \to c$ sectors. These allow us to estimate the scale of potential New Physics for generic extensions of the Standard Model. We then use the results to constrain the leptoquark landscape. |
2209.14605 | Bowen Fu | Bowen Fu and Stephen F. King | Gravitational wave signals from leptoquark-induced first order
electroweak phase transitions | 17 pages, 4 figures | JCAP05(2023)055 | 10.1088/1475-7516/2023/05/055 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We consider the extension of the Standard Model (SM) with scalar leptoquarks
in $SU(2)$ singlet, doublet and triplet representations. Through the coupling
between leptoquark and the SM Higgs field, the electroweak phase transition
(EWPT) can turn into first order and consequently produce gravitational wave
signals. We compute the required value of the leptoquark-Higgs for first order
EWPT to happen and discuss about the possible constraint from Higgs
phenomenology. Choosing some benchmarks, we present the strength of the
gravitational waves produced during the leptoquark-induced first order EWPT and
compare them to detector sensitivities. We find that the $SU(2)$
representations of the leptoquark can be distinguished by gravitational waves
in the parameter space where first order EWPT can happen as a function of the
Higgs portal coupling.
| [
{
"created": "Thu, 29 Sep 2022 07:52:28 GMT",
"version": "v1"
},
{
"created": "Wed, 5 Oct 2022 13:28:23 GMT",
"version": "v2"
},
{
"created": "Fri, 19 May 2023 09:56:09 GMT",
"version": "v3"
}
] | 2023-05-30 | [
[
"Fu",
"Bowen",
""
],
[
"King",
"Stephen F.",
""
]
] | We consider the extension of the Standard Model (SM) with scalar leptoquarks in $SU(2)$ singlet, doublet and triplet representations. Through the coupling between leptoquark and the SM Higgs field, the electroweak phase transition (EWPT) can turn into first order and consequently produce gravitational wave signals. We compute the required value of the leptoquark-Higgs for first order EWPT to happen and discuss about the possible constraint from Higgs phenomenology. Choosing some benchmarks, we present the strength of the gravitational waves produced during the leptoquark-induced first order EWPT and compare them to detector sensitivities. We find that the $SU(2)$ representations of the leptoquark can be distinguished by gravitational waves in the parameter space where first order EWPT can happen as a function of the Higgs portal coupling. |
2203.13107 | Marzia Bordone | Marzia Bordone, Paolo Gambino | The semileptonic $B_s$ and $\Lambda_b$ widths | Contribution to the 11th International Workshop on the CKM Unitarity
Triangle (CKM2021) | null | null | CERN-TH-2022-050 | hep-ph hep-ex | http://creativecommons.org/licenses/by/4.0/ | We present estimates of the semileptonic widths of the $B_s$ and $\Lambda_b$
hadrons. We employ the latest fit to the $B$ inclusive semileptonic data, the
heavy quark expansion and lattice QCD results. Our results suffer from large
uncertainties that could be reduced with dedicated measurements and new lattice
QCD calculations.
| [
{
"created": "Thu, 24 Mar 2022 15:05:26 GMT",
"version": "v1"
}
] | 2022-03-28 | [
[
"Bordone",
"Marzia",
""
],
[
"Gambino",
"Paolo",
""
]
] | We present estimates of the semileptonic widths of the $B_s$ and $\Lambda_b$ hadrons. We employ the latest fit to the $B$ inclusive semileptonic data, the heavy quark expansion and lattice QCD results. Our results suffer from large uncertainties that could be reduced with dedicated measurements and new lattice QCD calculations. |
hep-ph/0701241 | Sergey Troshin | S.M. Troshin, N.E. Tyurin | Reflective scattering from unitarity saturation | 15 pages, 3 figures, extended version | Int.J.Mod.Phys.A22:4437-4449,2007 | 10.1142/S0217751X0703697X | null | hep-ph | null | Proceeding from optical analogy we propose a new physical interpretation of
unitarity saturation leading to antishadowing as a reflective scattering. This
interpretation of antishadowing is related to the non-perturbative aspects of
strong interactions and follows from the specific property of the unitarity
saturation when elastic $S$-matrix $S(s,b)|_{b=0}\to -1$ at $s\to \infty$. The
analogy with Berry phase and experimental consequences of the proposed
interpretation as reflective scattering at the LHC and in the cosmic rays
studies are discussed.
| [
{
"created": "Mon, 29 Jan 2007 14:20:46 GMT",
"version": "v1"
},
{
"created": "Wed, 31 Jan 2007 11:59:56 GMT",
"version": "v2"
},
{
"created": "Tue, 8 May 2007 09:26:32 GMT",
"version": "v3"
},
{
"created": "Mon, 4 Jun 2007 12:23:27 GMT",
"version": "v4"
}
] | 2008-11-26 | [
[
"Troshin",
"S. M.",
""
],
[
"Tyurin",
"N. E.",
""
]
] | Proceeding from optical analogy we propose a new physical interpretation of unitarity saturation leading to antishadowing as a reflective scattering. This interpretation of antishadowing is related to the non-perturbative aspects of strong interactions and follows from the specific property of the unitarity saturation when elastic $S$-matrix $S(s,b)|_{b=0}\to -1$ at $s\to \infty$. The analogy with Berry phase and experimental consequences of the proposed interpretation as reflective scattering at the LHC and in the cosmic rays studies are discussed. |
hep-ph/9801278 | M. A. Braun | M.A.Braun | On the diffraction in the perturbative QCD | 9 pages, 1 table, LaTex | Phys.Lett. B425 (1998) 354-358 | 10.1016/S0370-2693(98)00253-6 | SPbU-IP-1998-2 | hep-ph | null | In the framework of the hard pomeron model it is shown that at large $Q^2$
the diffractive contribution to the structure functions rises as $Q^{0.3362}$
and much slowlier than the total contribution rising as $Q$.
| [
{
"created": "Tue, 13 Jan 1998 09:28:49 GMT",
"version": "v1"
}
] | 2009-10-31 | [
[
"Braun",
"M. A.",
""
]
] | In the framework of the hard pomeron model it is shown that at large $Q^2$ the diffractive contribution to the structure functions rises as $Q^{0.3362}$ and much slowlier than the total contribution rising as $Q$. |
hep-ph/0401060 | Torbjorn Sjostrand | T. Sjostrand and P. Skands | Multiple Interactions and Beam Remnants | LaTeX, 5 pages, submitted to the proceedings of the Workshop on
Physics at TeV Colliders, Les Houches, France, 26 May - 6 June 2003 | null | null | LU TP 04-04 | hep-ph | null | Open issues on the structure of multiple interactions are outlined. An
improved model is summarized, with a new approach to correlated parton
densities in flavour, colour, longitudinal and transverse momenta, for both
hard-scattering partons and beam-remnant ones.
| [
{
"created": "Sat, 10 Jan 2004 12:42:35 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Sjostrand",
"T.",
""
],
[
"Skands",
"P.",
""
]
] | Open issues on the structure of multiple interactions are outlined. An improved model is summarized, with a new approach to correlated parton densities in flavour, colour, longitudinal and transverse momenta, for both hard-scattering partons and beam-remnant ones. |
1410.0362 | Matthew Walters | Christopher Brust, Petar Maksimovic, Alice Sady, Prashant Saraswat,
Matthew T. Walters, Yongjie Xin | Identifying boosted new physics with non-isolated leptons | 15 pages plus references, 11 figures; references added | JHEP 04 (2015) 079 | 10.1007/JHEP04(2015)079 | UMD-PP-014-011 | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We demonstrate the utility of leptons which fail standard isolation criteria
in searches for new physics at the LHC. Such leptons can arise in any event
containing a highly boosted particle which decays to both leptons and quarks.
We begin by considering multiple extensions to the Standard Model which
primarily lead to events with non-isolated leptons and are therefore missed by
current search strategies. We emphasize the failure of standard isolation
variables to adequately discriminate between signal and SM background for any
value of the isolation cuts. We then introduce a new approach which makes use
of jet substructure techniques to distinguish a broad range of signals from QCD
events. We proceed with a simulated, proof-of-principle search for R-parity
violating supersymmetry to demonstrate both the experimental reach possible
with the use of non-isolated leptons and the utility of new substructure
variables over existing techniques
| [
{
"created": "Wed, 1 Oct 2014 20:00:10 GMT",
"version": "v1"
},
{
"created": "Sun, 25 Jan 2015 22:21:49 GMT",
"version": "v2"
}
] | 2015-05-14 | [
[
"Brust",
"Christopher",
""
],
[
"Maksimovic",
"Petar",
""
],
[
"Sady",
"Alice",
""
],
[
"Saraswat",
"Prashant",
""
],
[
"Walters",
"Matthew T.",
""
],
[
"Xin",
"Yongjie",
""
]
] | We demonstrate the utility of leptons which fail standard isolation criteria in searches for new physics at the LHC. Such leptons can arise in any event containing a highly boosted particle which decays to both leptons and quarks. We begin by considering multiple extensions to the Standard Model which primarily lead to events with non-isolated leptons and are therefore missed by current search strategies. We emphasize the failure of standard isolation variables to adequately discriminate between signal and SM background for any value of the isolation cuts. We then introduce a new approach which makes use of jet substructure techniques to distinguish a broad range of signals from QCD events. We proceed with a simulated, proof-of-principle search for R-parity violating supersymmetry to demonstrate both the experimental reach possible with the use of non-isolated leptons and the utility of new substructure variables over existing techniques |
0912.0477 | Saul Ramos-Sanchez | Oleg Lebedev and Saul Ramos-Sanchez | The NMSSM and String Theory | 10 pages; v2: typos corrected | Phys.Lett.B684:48-51,2010 | 10.1016/j.physletb.2009.12.058 | DESY-09-213 | hep-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study the possibility of constructing the NMSSM from the heterotic string.
String derived NMSSMs are much more rare than MSSMs due to the extra
requirement that there exist a light singlet which couples to the Higgs pairs.
They share the common feature that the singlet self-interactions are typically
suppressed, leading to either the "decoupling" or the Peccei-Quinn limit of the
NMSSM. In the latter case, the spectrum contains a light pseudoscalar which may
be relevant to the MSSM fine-tuning problem. We provide a Z_6 heterotic
orbifold example of the NMSSM with approximate Peccei-Quinn symmetry, whose
origin lies in the string selection rules combined with our choice of the
vacuum configuration.
| [
{
"created": "Wed, 2 Dec 2009 17:47:46 GMT",
"version": "v1"
},
{
"created": "Fri, 11 Dec 2009 15:50:36 GMT",
"version": "v2"
}
] | 2010-04-30 | [
[
"Lebedev",
"Oleg",
""
],
[
"Ramos-Sanchez",
"Saul",
""
]
] | We study the possibility of constructing the NMSSM from the heterotic string. String derived NMSSMs are much more rare than MSSMs due to the extra requirement that there exist a light singlet which couples to the Higgs pairs. They share the common feature that the singlet self-interactions are typically suppressed, leading to either the "decoupling" or the Peccei-Quinn limit of the NMSSM. In the latter case, the spectrum contains a light pseudoscalar which may be relevant to the MSSM fine-tuning problem. We provide a Z_6 heterotic orbifold example of the NMSSM with approximate Peccei-Quinn symmetry, whose origin lies in the string selection rules combined with our choice of the vacuum configuration. |
1804.05068 | Benjamin Fuks | Stefano Colucci, Benjamin Fuks, Federica Giacchino, Laura Lopez
Honorez, Michel H.G. Tytgat and J\'er\^ome Vandecasteele | Top-philic Vector-Like Portal to Scalar Dark Matter | 15 pages, 11 figures; version accepted by PRD | Phys. Rev. D 98, 035002 (2018) | 10.1103/PhysRevD.98.035002 | ULB-TH/18-04 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We investigate the phenomenology of scalar singlet dark matter candidates
that couple dominantly to the Standard Model via a Yukawa interaction with the
top quark and a colored vector-like fermion. We estimate the viability of this
vector-like portal scenario with respect to the most recent bounds from dark
matter direct and indirect detection, as well as to dark matter and vector-like
mediator searches at colliders. Moreover, we take QCD radiative corrections
into account in all our theoretical calculations. This work complements
analyses related both to models featuring a scalar singlet coupled through a
vector-like portal to light quarks, and to scenarios in which the dark matter
is a Majorana singlet coupled to the Standard Model through scalar colored
particles (akin to simplified models inspired by supersymmetry). Our study puts
especially forward the complementarity of different search strategies from
different contexts, and we show that current experiments allow for testing dark
matter masses ranging up to 700 GeV and mediator masses ranging up to 6 TeV.
| [
{
"created": "Fri, 13 Apr 2018 18:00:04 GMT",
"version": "v1"
},
{
"created": "Thu, 26 Jul 2018 12:44:17 GMT",
"version": "v2"
}
] | 2018-08-08 | [
[
"Colucci",
"Stefano",
""
],
[
"Fuks",
"Benjamin",
""
],
[
"Giacchino",
"Federica",
""
],
[
"Honorez",
"Laura Lopez",
""
],
[
"Tytgat",
"Michel H. G.",
""
],
[
"Vandecasteele",
"Jérôme",
""
]
] | We investigate the phenomenology of scalar singlet dark matter candidates that couple dominantly to the Standard Model via a Yukawa interaction with the top quark and a colored vector-like fermion. We estimate the viability of this vector-like portal scenario with respect to the most recent bounds from dark matter direct and indirect detection, as well as to dark matter and vector-like mediator searches at colliders. Moreover, we take QCD radiative corrections into account in all our theoretical calculations. This work complements analyses related both to models featuring a scalar singlet coupled through a vector-like portal to light quarks, and to scenarios in which the dark matter is a Majorana singlet coupled to the Standard Model through scalar colored particles (akin to simplified models inspired by supersymmetry). Our study puts especially forward the complementarity of different search strategies from different contexts, and we show that current experiments allow for testing dark matter masses ranging up to 700 GeV and mediator masses ranging up to 6 TeV. |
2112.03375 | Maxim Khlopov | Maxim Yu. Khlopov | BSM Cosmology from BSM Physics | Prepared for Proceedings of XXIV Bled Workshop "What comes beyond the
Standard models?" | null | null | null | hep-ph astro-ph.CO astro-ph.HE | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Now Standard $\Lambda$CDM cosmology is based on physics Beyond the Standard
Model (BSM), which in turn needs cosmological probes for its study. This
vicious circle of problems can be resolved by methods of cosmoparticle physics,
in which cosmological messengers of new physics provide sensitive model
dependent probes for BSM physics. Such messengers, which are inevitably present
in any BSM basis for now Standard cosmology, lead to deviations from the
Standard cosmological paradigm. We give brief review of some possible
cosmological features and messengers of BSM physics, which include balancing of
baryon asymmetry and dark matter by sphaleron transitions, hadronic dark matter
and exotic cosmic ray components, a solution for puzzles of direct dark matter
searches in dark atom model, antimatter in baryon asymmetrical Universe as
sensitive probe for models of inflation and baryosynthesis and its possible
probe in AMS02 experiment, PBH and GW messengers of BSM models and phase
transitions in early Universe. These aspects are discussed in the general
framework of methods of cosmoparticle physics.
| [
{
"created": "Mon, 6 Dec 2021 22:00:28 GMT",
"version": "v1"
}
] | 2021-12-08 | [
[
"Khlopov",
"Maxim Yu.",
""
]
] | Now Standard $\Lambda$CDM cosmology is based on physics Beyond the Standard Model (BSM), which in turn needs cosmological probes for its study. This vicious circle of problems can be resolved by methods of cosmoparticle physics, in which cosmological messengers of new physics provide sensitive model dependent probes for BSM physics. Such messengers, which are inevitably present in any BSM basis for now Standard cosmology, lead to deviations from the Standard cosmological paradigm. We give brief review of some possible cosmological features and messengers of BSM physics, which include balancing of baryon asymmetry and dark matter by sphaleron transitions, hadronic dark matter and exotic cosmic ray components, a solution for puzzles of direct dark matter searches in dark atom model, antimatter in baryon asymmetrical Universe as sensitive probe for models of inflation and baryosynthesis and its possible probe in AMS02 experiment, PBH and GW messengers of BSM models and phase transitions in early Universe. These aspects are discussed in the general framework of methods of cosmoparticle physics. |
1305.2715 | Mundur Murthy | M V N Murthy and G Rajasekaran | Anomalous Kolar events revisited: Dark Matter? | 6 pages; 1 figure added | Pramana, J.Phys. 82 (2014) L609 | 10.1007/s12043-014-0718-5 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The possibility of the unexplained Kolar events, recorded in the 70's and
80's, being due to the decays of dark matter particles of mass in the range of
5--10 GeV is pointed out.
| [
{
"created": "Mon, 13 May 2013 09:23:43 GMT",
"version": "v1"
},
{
"created": "Sat, 1 Jun 2013 05:01:31 GMT",
"version": "v2"
},
{
"created": "Fri, 18 Apr 2014 06:50:24 GMT",
"version": "v3"
}
] | 2015-06-15 | [
[
"Murthy",
"M V N",
""
],
[
"Rajasekaran",
"G",
""
]
] | The possibility of the unexplained Kolar events, recorded in the 70's and 80's, being due to the decays of dark matter particles of mass in the range of 5--10 GeV is pointed out. |
1308.3797 | Zack Sullivan | Zack Sullivan | Next-to-leading order pp -> W^\prime -> tb production at 14 TeV and 33
TeV | 6 pages, to appear in the Proceedings of the 2013 Community Summer
Study - Snowmass on the Mississippi | null | null | IIT-CAPP-13-07 | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | I update the predicted leading order and next-to-leading order cross sections
and total widths for W^\prime bosons that decay to top and bottom quarks at 14
TeV and 33 TeV pp colliders (pp -> W^\prime -> tb). Separate tables are
included for right- and left-handed bosons. Theoretical uncertainties are
completely dominated by parton distribution function uncertainties, and are
computed for W^\prime_+- production at a 14 TeV pp collider.
| [
{
"created": "Sat, 17 Aug 2013 17:17:23 GMT",
"version": "v1"
}
] | 2013-08-20 | [
[
"Sullivan",
"Zack",
""
]
] | I update the predicted leading order and next-to-leading order cross sections and total widths for W^\prime bosons that decay to top and bottom quarks at 14 TeV and 33 TeV pp colliders (pp -> W^\prime -> tb). Separate tables are included for right- and left-handed bosons. Theoretical uncertainties are completely dominated by parton distribution function uncertainties, and are computed for W^\prime_+- production at a 14 TeV pp collider. |
hep-ph/0011374 | Tatsuya Noguchi | Masako Bando (Aichi U.) and Tatsuya Noguchi (Kyoto U.) | Brane Fluctuation and New Counting Rules for Kaluza-Klein Towers | 9 pages, LaTeX, typos corrected and a KUNS preprint number changed | null | null | KUNS-1698 | hep-ph | null | In models with extra dimensions, branes have been usually treated as solid
bodies though they are prohibited by the relativity. In the previous letter, we
proposed a method of taking account of brane fluctuation by introducing
Nambu-Goldstone bosons, and prove that when a tension of the brane is small,
the interaction between boundary fields and Kaluza-Klein modes is suppressed
exponentially. In this letter, we further investigate this suppression in more
generic configuration, and obtain three counting rules, ``AND'', ``OR'' and
``STACK'' rules, depending on the softness of branes and the character of
fields on the branes four dimensions. The choice determines the number of
Kaluza-Klein towers contributing to renormalization group equations, leading to
a remarkable change in the running behavior of coupling constants.
| [
{
"created": "Wed, 29 Nov 2000 18:49:41 GMT",
"version": "v1"
},
{
"created": "Fri, 19 Jan 2001 08:10:54 GMT",
"version": "v2"
}
] | 2007-05-23 | [
[
"Bando",
"Masako",
"",
"Aichi U."
],
[
"Noguchi",
"Tatsuya",
"",
"Kyoto U."
]
] | In models with extra dimensions, branes have been usually treated as solid bodies though they are prohibited by the relativity. In the previous letter, we proposed a method of taking account of brane fluctuation by introducing Nambu-Goldstone bosons, and prove that when a tension of the brane is small, the interaction between boundary fields and Kaluza-Klein modes is suppressed exponentially. In this letter, we further investigate this suppression in more generic configuration, and obtain three counting rules, ``AND'', ``OR'' and ``STACK'' rules, depending on the softness of branes and the character of fields on the branes four dimensions. The choice determines the number of Kaluza-Klein towers contributing to renormalization group equations, leading to a remarkable change in the running behavior of coupling constants. |
2102.11292 | Federico Meloni | Rodolfo Capdevilla, Federico Meloni, Rosa Simoniello, Jose Zurita | Hunting wino and higgsino dark matter at the muon collider with
disappearing tracks | 32 pages, 18 figures, 3 tables, v2: corrected numerical error for
non-integer log10(lifetime) | null | 10.1007/JHEP06(2021)133 | DESY 21-019, IFIC/21-03 | hep-ph | http://creativecommons.org/licenses/by/4.0/ | We study the capabilities of a muon collider experiment to detect
disappearing tracks originating when a heavy and electrically charged
long-lived particle decays via $X^+ \to Y^+ Z^0$, where $X^+$ and $Z^0$ are two
almost mass degenerate new states and $Y^+$ is a charged Standard Model
particle. The backgrounds induced by the in-flight decays of the muon beams
(BIB) can create detector hit combinations that mimic long-lived particle
signatures, making the search a daunting task. We design a simple strategy to
tame the BIB, based on a detector-hit-level selection exploiting timing
information and hit-to-hit correlations, followed by simple requirements on the
quality of reconstructed tracks. Our strategy allows us to reduce the number of
tracks from BIB to an average of 0.08 per event, hence being able to design a
cut-and-count analysis that shows that it is possible to cover weak doublets
and triplets with masses close to $\sqrt{s}/2$ in the 0.1-10 ns range. In
particular, this implies that a 10 TeV muon collider is able to probe thermal
MSSM higgsinos and thermal MSSM winos, thus rivaling the FCC-hh in that
respect, and further enlarging the physics program of the muon collider into
the territory of WIMP dark matter and long-lived signatures. We also provide
parton-to-reconstructed level efficiency maps, allowing an estimation of the
coverage of disappearing tracks at muon colliders for arbitrary models.
| [
{
"created": "Mon, 22 Feb 2021 19:00:08 GMT",
"version": "v1"
},
{
"created": "Fri, 18 Aug 2023 16:13:13 GMT",
"version": "v2"
}
] | 2023-08-21 | [
[
"Capdevilla",
"Rodolfo",
""
],
[
"Meloni",
"Federico",
""
],
[
"Simoniello",
"Rosa",
""
],
[
"Zurita",
"Jose",
""
]
] | We study the capabilities of a muon collider experiment to detect disappearing tracks originating when a heavy and electrically charged long-lived particle decays via $X^+ \to Y^+ Z^0$, where $X^+$ and $Z^0$ are two almost mass degenerate new states and $Y^+$ is a charged Standard Model particle. The backgrounds induced by the in-flight decays of the muon beams (BIB) can create detector hit combinations that mimic long-lived particle signatures, making the search a daunting task. We design a simple strategy to tame the BIB, based on a detector-hit-level selection exploiting timing information and hit-to-hit correlations, followed by simple requirements on the quality of reconstructed tracks. Our strategy allows us to reduce the number of tracks from BIB to an average of 0.08 per event, hence being able to design a cut-and-count analysis that shows that it is possible to cover weak doublets and triplets with masses close to $\sqrt{s}/2$ in the 0.1-10 ns range. In particular, this implies that a 10 TeV muon collider is able to probe thermal MSSM higgsinos and thermal MSSM winos, thus rivaling the FCC-hh in that respect, and further enlarging the physics program of the muon collider into the territory of WIMP dark matter and long-lived signatures. We also provide parton-to-reconstructed level efficiency maps, allowing an estimation of the coverage of disappearing tracks at muon colliders for arbitrary models. |
hep-ph/0412301 | Ramona Vogt | R. Vogt | Heavy Ion Physics at the LHC | 10 pages, 2 figures, proceedings of INPC 04 in Goteborg, Sweden, July
2004, includes conference style file | Nucl.Phys. A752 (2005) 447-456 | 10.1016/j.nuclphysa.2005.02.050 | null | hep-ph | null | The ion-ion center of mass energies at the LHC will exceed that at RHIC by
nearly a factor of 30, providing exciting opportunities for addressing unique
physics issues in a completely new energy domain. Some highlights of this new
physics domain are presented here. We briefly describe how these collisions
will provide new insights into the high density, low momentum gluon content of
the nucleus expected to dominate the dynamics of the early state of the system.
We then discuss how the dense initial state of the nucleus affects the lifetime
and temperature of the produced system. Finally, we explain how the high energy
domain of the LHC allows abundant production of `rare' processes, hard probes
calculable in perturbative quantum chromodynamics, QCD. At the LHC, high
momentum jets and $b \bar b$ bound states, the $\Upsilon$ family, will be
produced with high statistics for the first time in heavy ion collisions.
| [
{
"created": "Tue, 21 Dec 2004 00:45:17 GMT",
"version": "v1"
}
] | 2009-11-10 | [
[
"Vogt",
"R.",
""
]
] | The ion-ion center of mass energies at the LHC will exceed that at RHIC by nearly a factor of 30, providing exciting opportunities for addressing unique physics issues in a completely new energy domain. Some highlights of this new physics domain are presented here. We briefly describe how these collisions will provide new insights into the high density, low momentum gluon content of the nucleus expected to dominate the dynamics of the early state of the system. We then discuss how the dense initial state of the nucleus affects the lifetime and temperature of the produced system. Finally, we explain how the high energy domain of the LHC allows abundant production of `rare' processes, hard probes calculable in perturbative quantum chromodynamics, QCD. At the LHC, high momentum jets and $b \bar b$ bound states, the $\Upsilon$ family, will be produced with high statistics for the first time in heavy ion collisions. |
1909.12899 | Tobias Wistisen | T. N. Wistisen and A. Di Piazza | Numerical approach to the semiclassical method of radiation emission for
arbitrary electron spin and photon polarization | null | Phys. Rev. D 100, 116001 (2019) | 10.1103/PhysRevD.100.116001 | null | hep-ph physics.plasm-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We show how the semiclassical formulas for radiation emission of Baier,
Katkov and Strakhovenko for arbitrary initial and final spins of the electron
and arbitrary polarization of the emitted photon can be rewritten in a form
which numerically converges quickly. We directly compare the method in the case
of a background plane wave with the result obtained by using the Volkov state
solution of the Dirac equation, and confirm that we obtain the same result. We
then investigate the interaction of a circularly polarized short laser pulse
scattering with GeV electrons and see that the finite duration of the pulse
leads to a lower transfer of circular polarization than that predicted by the
known formulas in the monochromatic case. We also see how the transfer of
circular polarization from the laser beam to the gamma ray beam is gradually
deteriorated as the laser intensity increases, entering the nonlinear regime.
However, this is shown to be recovered if the scattered photon beam is
collimated to only allow for passage of photons emitted with angles smaller
than $1/\gamma$ with respect to the initial electron direction, where $\gamma$
is the approximately constant Lorentz factor of the electron. The obtained
formulas also allow us to answer questions regarding radiative polarization of
the emitting particles. In this respect we briefly discuss an application of
the present approach to the case of a bent crystal and high-energy positrons.
| [
{
"created": "Fri, 27 Sep 2019 20:33:34 GMT",
"version": "v1"
}
] | 2019-12-11 | [
[
"Wistisen",
"T. N.",
""
],
[
"Di Piazza",
"A.",
""
]
] | We show how the semiclassical formulas for radiation emission of Baier, Katkov and Strakhovenko for arbitrary initial and final spins of the electron and arbitrary polarization of the emitted photon can be rewritten in a form which numerically converges quickly. We directly compare the method in the case of a background plane wave with the result obtained by using the Volkov state solution of the Dirac equation, and confirm that we obtain the same result. We then investigate the interaction of a circularly polarized short laser pulse scattering with GeV electrons and see that the finite duration of the pulse leads to a lower transfer of circular polarization than that predicted by the known formulas in the monochromatic case. We also see how the transfer of circular polarization from the laser beam to the gamma ray beam is gradually deteriorated as the laser intensity increases, entering the nonlinear regime. However, this is shown to be recovered if the scattered photon beam is collimated to only allow for passage of photons emitted with angles smaller than $1/\gamma$ with respect to the initial electron direction, where $\gamma$ is the approximately constant Lorentz factor of the electron. The obtained formulas also allow us to answer questions regarding radiative polarization of the emitting particles. In this respect we briefly discuss an application of the present approach to the case of a bent crystal and high-energy positrons. |
2012.09986 | Wenyu Wang | Guo-Li Liu, Fei Wang, Wenyu Wang | The Lepton Flavor Changing Decays and One-loop Muon Anomalous Magnetic
Moment in the Extended Mirror Twin Higgs Models | 24 pages, 12 figures | null | null | null | hep-ph | http://creativecommons.org/licenses/by/4.0/ | Mirror Twin Higgs(MTH) models always contain heavy gauge bosons and extra
Higgses. Besides, to accommodate tiny neutrino masses via seesaw mechanism, new
heavy neutrinos can also be introduced in MTH extension models. Such new
particles and interactions may lead to new contributions to the lepton flavor
violating (LFV) processes, including $\ell_i \to \ell_j\gamma$ and $\ell_i \to
\ell_j\ell_k\ell_l$. We find that current experimental data can stringently
constrain the parameter spaces and certain LFV processes can possibly be tested
by the next generation colliders. One-loop contributions of the new particles
to the muon anomalous magnetic momentumare also calculated. Such contributions
can still not solve the discrepancy between the experiments and the prediction
of the standard model.
| [
{
"created": "Fri, 18 Dec 2020 00:18:08 GMT",
"version": "v1"
}
] | 2020-12-21 | [
[
"Liu",
"Guo-Li",
""
],
[
"Wang",
"Fei",
""
],
[
"Wang",
"Wenyu",
""
]
] | Mirror Twin Higgs(MTH) models always contain heavy gauge bosons and extra Higgses. Besides, to accommodate tiny neutrino masses via seesaw mechanism, new heavy neutrinos can also be introduced in MTH extension models. Such new particles and interactions may lead to new contributions to the lepton flavor violating (LFV) processes, including $\ell_i \to \ell_j\gamma$ and $\ell_i \to \ell_j\ell_k\ell_l$. We find that current experimental data can stringently constrain the parameter spaces and certain LFV processes can possibly be tested by the next generation colliders. One-loop contributions of the new particles to the muon anomalous magnetic momentumare also calculated. Such contributions can still not solve the discrepancy between the experiments and the prediction of the standard model. |
1506.09082 | Stanislaw Mrowczynski | Margaret E. Carrington, Katarzyna Deja and Stanislaw Mrowczynski | Energy Loss in Unstable Quark-Gluon Plasma | 23 pages, 11 figures, minor changes, to appear in Phys. Rev. C | Phys. Rev. C 92, 044914 (2015) | 10.1103/PhysRevC.92.044914 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The momentum distribution of quark-gluon plasma at the early stage of a
relativistic heavy-ion collision is anisotropic and consequently the system,
which is assumed to be weakly coupled, is unstable due chromomagnetic plasma
modes. We consider a high-energy parton which flies across such an unstable
plasma, and the energy transfer between the parton and the medium is studied as
an initial value problem. In the case of equilibrium plasmas, the well-known
formula of collisional energy loss is reproduced. The unstable plasma case is
much more complex, and the parton can lose or gain energy depending on the
initial conditions. The extremely prolate and extremely oblate systems are
considered as examples of unstable plasmas, and two classes of initial
conditions are discussed. When the initial chromodynamic field is uncorrelated
with the color state of the parton, it typically looses energy, and the
magnitude of the energy loss is comparable to that in an equilibrium plasma of
the same density. When the initial chromodynamic field is induced by the
parton, it can be either accelerated or decelerated depending on the relative
phase factor. With a correlated initial condition, the energy transfer grows
exponentially in time and its magnitude can much exceed the absolute value of
energy loss in an equilibrium plasma. The energy transfer is also strongly
directionally dependent. Consequences of our findings for the phenomenology of
jet quenching in relativistic heavy-ion collisions are briefly discussed.
| [
{
"created": "Tue, 30 Jun 2015 13:38:21 GMT",
"version": "v1"
},
{
"created": "Thu, 8 Oct 2015 10:20:58 GMT",
"version": "v2"
}
] | 2015-11-04 | [
[
"Carrington",
"Margaret E.",
""
],
[
"Deja",
"Katarzyna",
""
],
[
"Mrowczynski",
"Stanislaw",
""
]
] | The momentum distribution of quark-gluon plasma at the early stage of a relativistic heavy-ion collision is anisotropic and consequently the system, which is assumed to be weakly coupled, is unstable due chromomagnetic plasma modes. We consider a high-energy parton which flies across such an unstable plasma, and the energy transfer between the parton and the medium is studied as an initial value problem. In the case of equilibrium plasmas, the well-known formula of collisional energy loss is reproduced. The unstable plasma case is much more complex, and the parton can lose or gain energy depending on the initial conditions. The extremely prolate and extremely oblate systems are considered as examples of unstable plasmas, and two classes of initial conditions are discussed. When the initial chromodynamic field is uncorrelated with the color state of the parton, it typically looses energy, and the magnitude of the energy loss is comparable to that in an equilibrium plasma of the same density. When the initial chromodynamic field is induced by the parton, it can be either accelerated or decelerated depending on the relative phase factor. With a correlated initial condition, the energy transfer grows exponentially in time and its magnitude can much exceed the absolute value of energy loss in an equilibrium plasma. The energy transfer is also strongly directionally dependent. Consequences of our findings for the phenomenology of jet quenching in relativistic heavy-ion collisions are briefly discussed. |
0802.4015 | Yuji Kajiyama | Andi Hektor, Yuji Kajiyama and Kristjan Kannike | Muon Anomalous Magnetic Moment and Lepton Flavor Violating Tau Decay in
Unparticle Physics | 12 pages, 7 figures | Phys.Rev.D78:053008,2008 | 10.1103/PhysRevD.78.053008 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study effects of unparticle physics on muon g-2 and LFV tau decay
processes. LFV interactions between the Standard Model sector and unparticles
can explain the difference of experimental value of muon g-2 from the Standard
Model prediction. While the same couplings generate LFV tau decay, we found
that LFV coupling can be of O(0.1 ... 1) without conflict with experimental
bounds of LFV tau decay if the scaling dimension of unparticle operator d_{U} >
1.6.
| [
{
"created": "Wed, 27 Feb 2008 13:15:17 GMT",
"version": "v1"
},
{
"created": "Thu, 2 Oct 2008 17:06:18 GMT",
"version": "v2"
}
] | 2008-11-26 | [
[
"Hektor",
"Andi",
""
],
[
"Kajiyama",
"Yuji",
""
],
[
"Kannike",
"Kristjan",
""
]
] | We study effects of unparticle physics on muon g-2 and LFV tau decay processes. LFV interactions between the Standard Model sector and unparticles can explain the difference of experimental value of muon g-2 from the Standard Model prediction. While the same couplings generate LFV tau decay, we found that LFV coupling can be of O(0.1 ... 1) without conflict with experimental bounds of LFV tau decay if the scaling dimension of unparticle operator d_{U} > 1.6. |
2001.00017 | Nathaniel Craig | Nathaniel Craig, Minyuan Jiang, Ying-Ying Li, Dave Sutherland | Loops and trees in generic EFTs | 29+1 pages, 5 figures, 6 tables | null | 10.1007/JHEP08(2020)086 | FERMILAB-PUB-19-646-T | hep-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We consider aspects of tree and one-loop behavior in a generic 4d EFT of
massless scalars, fermions, and vectors, with a particular eye to the
high-energy limit of the Standard Model EFT at operator dimensions 6 and 8.
First, we classify the possible Lorentz structures of operators and the subset
of these that can arise at tree-level in a weakly coupled UV completion,
extending the tree/loop classification through dimension 8 using functional
methods. Second, we investigate how operators contribute to tree and one-loop
helicity amplitudes, exploring the impact of non-renormalization theorems
through dimension 8. We further observe that many dimension 6 contributions to
helicity amplitudes, including rational parts, vanish exactly at one-loop
level. This suggests the impact of helicity selection rules extends beyond one
loop in non-supersymmetric EFTs.
| [
{
"created": "Tue, 31 Dec 2019 19:00:00 GMT",
"version": "v1"
}
] | 2023-01-10 | [
[
"Craig",
"Nathaniel",
""
],
[
"Jiang",
"Minyuan",
""
],
[
"Li",
"Ying-Ying",
""
],
[
"Sutherland",
"Dave",
""
]
] | We consider aspects of tree and one-loop behavior in a generic 4d EFT of massless scalars, fermions, and vectors, with a particular eye to the high-energy limit of the Standard Model EFT at operator dimensions 6 and 8. First, we classify the possible Lorentz structures of operators and the subset of these that can arise at tree-level in a weakly coupled UV completion, extending the tree/loop classification through dimension 8 using functional methods. Second, we investigate how operators contribute to tree and one-loop helicity amplitudes, exploring the impact of non-renormalization theorems through dimension 8. We further observe that many dimension 6 contributions to helicity amplitudes, including rational parts, vanish exactly at one-loop level. This suggests the impact of helicity selection rules extends beyond one loop in non-supersymmetric EFTs. |
1310.8410 | Christian Schubert | Jose Manuel Davila, Christian Schubert, Maria Anabel Trejo | Photonic processes in Born-Infeld theory | 22 pages, 7 figures, final published version (minor additions and
corrections) | International Journal of Modern Physics A Vol. 29 (2014) 1450174 | 10.1142/S0217751X14501747 | null | hep-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study the processes of photon-photon scattering and photon splitting in a
magnetic field in Born-Infeld theory. In both cases we combine the terms from
the tree-level Born-Infeld Lagrangian with the usual one-loop QED
contributions, where those are approximated by the Euler-Heisenberg Lagrangian,
including also the interference terms. For photon-photon scattering we obtain
the total cross section in the low-energy approximation. For photon splitting
we compute the total absorption coefficient in the hexagon (weak field)
approximation, and also show that, due to the non-birefringence property of
Born-Infeld theory, the selection rules found by Adler for the QED case
continue to hold in this more general setting. We discuss the bounds on the
free parameter of Born-Infeld theory that may be obtained from this type of
processes.
| [
{
"created": "Thu, 31 Oct 2013 07:10:21 GMT",
"version": "v1"
},
{
"created": "Mon, 1 Dec 2014 18:57:01 GMT",
"version": "v2"
}
] | 2014-12-02 | [
[
"Davila",
"Jose Manuel",
""
],
[
"Schubert",
"Christian",
""
],
[
"Trejo",
"Maria Anabel",
""
]
] | We study the processes of photon-photon scattering and photon splitting in a magnetic field in Born-Infeld theory. In both cases we combine the terms from the tree-level Born-Infeld Lagrangian with the usual one-loop QED contributions, where those are approximated by the Euler-Heisenberg Lagrangian, including also the interference terms. For photon-photon scattering we obtain the total cross section in the low-energy approximation. For photon splitting we compute the total absorption coefficient in the hexagon (weak field) approximation, and also show that, due to the non-birefringence property of Born-Infeld theory, the selection rules found by Adler for the QED case continue to hold in this more general setting. We discuss the bounds on the free parameter of Born-Infeld theory that may be obtained from this type of processes. |
hep-ph/0402013 | Anupam Mazumdar | A. Mazumdar | MSSM: source for generating perturbations | 4 pages, To appear in the Proceedings of SUSY 2003, held at the
University of Arizona, Tucson, AZ, 5-10 June 2003 | null | null | null | hep-ph | null | In this talk I describe how MSSM flat directions act as a source for
generating all matter and scale invariant adiabatic density perturbations with
a spectral index slightly depending upon the choice of a particular flat
direction.
| [
{
"created": "Sun, 1 Feb 2004 23:37:04 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Mazumdar",
"A.",
""
]
] | In this talk I describe how MSSM flat directions act as a source for generating all matter and scale invariant adiabatic density perturbations with a spectral index slightly depending upon the choice of a particular flat direction. |
hep-ph/0603071 | Kemal Ozeren | K.J. Ozeren and W.J. Stirling | Scattering amplitudes with massive fermions using BCFW recursion | 21 pages | Eur.Phys.J.C48:159-168,2006 | 10.1140/epjc/s10052-006-0007-7 | IPPP/06/15, DCPT/06/30 | hep-ph | null | We study the QCD scattering amplitudes for \bar{q}q \to gg and \bar{q}q \to
ggg where q is a massive fermion. Using a particular choice of massive fermion
spinor we are able to derive very compact expressions for the partial spin
amplitudes for the 2 \to 2 process. We then investigate the corresponding 2 \to
3 amplitudes using the BCFW recursion technique. For the helicity conserving
partial amplitudes we again derive very compact expressions, but were unable to
treat the helicity-flip amplitudes recursively, except for the case where all
the gluon helicities are the same. We therefore evaluate the remaining partial
amplitudes using standard Feynman diagram techniques.
| [
{
"created": "Thu, 9 Mar 2006 12:47:33 GMT",
"version": "v1"
}
] | 2009-01-07 | [
[
"Ozeren",
"K. J.",
""
],
[
"Stirling",
"W. J.",
""
]
] | We study the QCD scattering amplitudes for \bar{q}q \to gg and \bar{q}q \to ggg where q is a massive fermion. Using a particular choice of massive fermion spinor we are able to derive very compact expressions for the partial spin amplitudes for the 2 \to 2 process. We then investigate the corresponding 2 \to 3 amplitudes using the BCFW recursion technique. For the helicity conserving partial amplitudes we again derive very compact expressions, but were unable to treat the helicity-flip amplitudes recursively, except for the case where all the gluon helicities are the same. We therefore evaluate the remaining partial amplitudes using standard Feynman diagram techniques. |
0711.3169 | Kyrill Bugaev | Kyrill A. Bugaev | Exactly Solvable Model for the QCD Tricritcal Endpoint | 14 pages, 3 figures, invited talk given at the International Workshop
``Relativistic Nuclear Physics: from Nuclotron to LHC Energies'', Kiev,
Ukraine, June 18-22, 2007 | Phys.Atom.Nucl.71:1585-1593,2008 | 10.1134/S1063778808090147 | null | hep-ph | null | An inclusion of temperature and chemical potential dependent surface tension
into the gas of quark-gluon bags model resolves a long standing problem of a
unified description of the first and second order phase transition with the
cross-over. The suggested model has an exact analytical solution and allows one
to rigorously study the vicinity of the critical endpoint of the deconfinement
phase transition. It is found that at the curve of a zero surface tension
coefficient there must exist the surface induced phase tranition of the 2-nd or
higher order. The present model predicts that the critical endpoint (CEP) of
quantum chromodynamics is the tricritical endpoint.
| [
{
"created": "Tue, 20 Nov 2007 16:24:11 GMT",
"version": "v1"
}
] | 2008-11-26 | [
[
"Bugaev",
"Kyrill A.",
""
]
] | An inclusion of temperature and chemical potential dependent surface tension into the gas of quark-gluon bags model resolves a long standing problem of a unified description of the first and second order phase transition with the cross-over. The suggested model has an exact analytical solution and allows one to rigorously study the vicinity of the critical endpoint of the deconfinement phase transition. It is found that at the curve of a zero surface tension coefficient there must exist the surface induced phase tranition of the 2-nd or higher order. The present model predicts that the critical endpoint (CEP) of quantum chromodynamics is the tricritical endpoint. |
1512.06728 | Yang Zhang | Junjie Cao, Chengcheng Han, Liangliang Shang, Wei Su, Jin Min Yang,
Yang Zhang | Interpreting the 750 GeV diphoton excess by the singlet extension of the
Manohar-Wise Model | 19 pages, 3 figures | null | 10.1016/j.physletb.2016.02.045 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The evidence of a new scalar particle $X$ from the 750 GeV diphoton excess,
and the absence of any other signal of new physics at the LHC so far suggest
the existence of new colored scalars, which may be moderately light and thus
can induce sizable $X g g$ and $X \gamma \gamma$ couplings without resorting to
very strong interactions. Motivated by this speculation, we extend the
Manohar-Wise model by adding one gauge singlet scalar field. The resulting
theory then predicts one singlet dominated scalar $\phi$ as well as three kinds
of color-octet scalars, which can mediate through loops the $\phi gg$ and $\phi
\gamma \gamma$ interactions. After fitting the model to the diphoton data at
the LHC, we find that in reasonable parameter regions the excess can be
explained at $1\sigma$ level by the process $ g g \to \phi \to \gamma \gamma$,
and the best points predict the central value of the excess rate with
$\chi_{min}^2=2.32$, which corresponds to a $p$-value of $0.68$. We also
consider the constraints from various LHC Run I signals, and we conclude that,
although these constraints are powerful in excluding the parameter space of the
model, the best points are still experimentally allowed.
| [
{
"created": "Mon, 21 Dec 2015 17:49:35 GMT",
"version": "v1"
},
{
"created": "Tue, 22 Dec 2015 14:51:43 GMT",
"version": "v2"
},
{
"created": "Mon, 1 Feb 2016 03:28:04 GMT",
"version": "v3"
}
] | 2016-03-09 | [
[
"Cao",
"Junjie",
""
],
[
"Han",
"Chengcheng",
""
],
[
"Shang",
"Liangliang",
""
],
[
"Su",
"Wei",
""
],
[
"Yang",
"Jin Min",
""
],
[
"Zhang",
"Yang",
""
]
] | The evidence of a new scalar particle $X$ from the 750 GeV diphoton excess, and the absence of any other signal of new physics at the LHC so far suggest the existence of new colored scalars, which may be moderately light and thus can induce sizable $X g g$ and $X \gamma \gamma$ couplings without resorting to very strong interactions. Motivated by this speculation, we extend the Manohar-Wise model by adding one gauge singlet scalar field. The resulting theory then predicts one singlet dominated scalar $\phi$ as well as three kinds of color-octet scalars, which can mediate through loops the $\phi gg$ and $\phi \gamma \gamma$ interactions. After fitting the model to the diphoton data at the LHC, we find that in reasonable parameter regions the excess can be explained at $1\sigma$ level by the process $ g g \to \phi \to \gamma \gamma$, and the best points predict the central value of the excess rate with $\chi_{min}^2=2.32$, which corresponds to a $p$-value of $0.68$. We also consider the constraints from various LHC Run I signals, and we conclude that, although these constraints are powerful in excluding the parameter space of the model, the best points are still experimentally allowed. |
2403.08583 | Paolo Ciafaloni | Paolo Ciafaloni, Giampaolo Co', Dimitri Colferai and Denis Comelli | Electroweak Evolution Equations and Isospin Conservation | 10 pages, minor typos corrected | null | null | null | hep-ph hep-ex hep-th | http://creativecommons.org/licenses/by/4.0/ | In processes taking place at energies much higher than the weak scale,
electroweak corrections can be taken into account by using electroweak
evolution equations, that are analogous to the DGLAP equations in QCD. We show
that weak isospin conservation in these equations imposes to modify the
expressions of the splitting functions commonly used in the literature. These
modifications have a profound impact on the parton distribution functions.
| [
{
"created": "Wed, 13 Mar 2024 14:36:09 GMT",
"version": "v1"
},
{
"created": "Fri, 22 Mar 2024 09:34:18 GMT",
"version": "v2"
}
] | 2024-03-26 | [
[
"Ciafaloni",
"Paolo",
""
],
[
"Co'",
"Giampaolo",
""
],
[
"Colferai",
"Dimitri",
""
],
[
"Comelli",
"Denis",
""
]
] | In processes taking place at energies much higher than the weak scale, electroweak corrections can be taken into account by using electroweak evolution equations, that are analogous to the DGLAP equations in QCD. We show that weak isospin conservation in these equations imposes to modify the expressions of the splitting functions commonly used in the literature. These modifications have a profound impact on the parton distribution functions. |
1508.01458 | Heinrich P\"as | Arjun Berera, Roman V. Buniy, Thomas W. Kephart, Heinrich P\"as,
Jo\~ao G. Rosa | Knotty inflation and the dimensionality of spacetime | 5 pages | null | null | null | hep-ph astro-ph.CO gr-qc hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We suggest a structure for the vacuum comprised of a network of tightly
knotted/linked flux tubes formed in a QCD-like cosmological phase transition
and show that such a network can drive cosmological inflation. As the network
can be topologically stable only in three space dimensions, this scenario
provides a dynamical explanation for the existence of exactly three large
spatial dimensions in our Universe.
| [
{
"created": "Thu, 6 Aug 2015 17:11:25 GMT",
"version": "v1"
}
] | 2015-08-07 | [
[
"Berera",
"Arjun",
""
],
[
"Buniy",
"Roman V.",
""
],
[
"Kephart",
"Thomas W.",
""
],
[
"Päs",
"Heinrich",
""
],
[
"Rosa",
"João G.",
""
]
] | We suggest a structure for the vacuum comprised of a network of tightly knotted/linked flux tubes formed in a QCD-like cosmological phase transition and show that such a network can drive cosmological inflation. As the network can be topologically stable only in three space dimensions, this scenario provides a dynamical explanation for the existence of exactly three large spatial dimensions in our Universe. |
2405.00086 | Christopher Cappiello | Christopher Cappiello, Qinrui Liu, Gopolang Mohlabeng, Aaron C.
Vincent | Cosmic Ray-Boosted Dark Matter at IceCube | 7 pages, 5 figures | null | null | null | hep-ph astro-ph.CO astro-ph.HE | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Cosmic ray (CR) upscattering of dark matter is considered as one of the most
straightforward mechanisms to accelerate ambient dark matter, making it
detectable at high threshold, large volume experiments. In this work, we
revisit CR upscattered dark matter signals at the IceCube detector, focusing on
lower energy data than was considered before. We consider both scattering with
electrons and nuclei. In the latter, we include both elastic and deep-inelastic
scattering computations. As concrete examples, we consider two benchmark
models; Fermion dark matter with vector and scalar mediators. We compare our
model projections with the most current constraints and show that the IceCube
detector can detect CR-boosted dark matter especially with masses below $\sim$
100 keV when scattering with electrons and $\sim$ MeV in the nucleon scattering
case.
| [
{
"created": "Tue, 30 Apr 2024 18:00:00 GMT",
"version": "v1"
}
] | 2024-05-02 | [
[
"Cappiello",
"Christopher",
""
],
[
"Liu",
"Qinrui",
""
],
[
"Mohlabeng",
"Gopolang",
""
],
[
"Vincent",
"Aaron C.",
""
]
] | Cosmic ray (CR) upscattering of dark matter is considered as one of the most straightforward mechanisms to accelerate ambient dark matter, making it detectable at high threshold, large volume experiments. In this work, we revisit CR upscattered dark matter signals at the IceCube detector, focusing on lower energy data than was considered before. We consider both scattering with electrons and nuclei. In the latter, we include both elastic and deep-inelastic scattering computations. As concrete examples, we consider two benchmark models; Fermion dark matter with vector and scalar mediators. We compare our model projections with the most current constraints and show that the IceCube detector can detect CR-boosted dark matter especially with masses below $\sim$ 100 keV when scattering with electrons and $\sim$ MeV in the nucleon scattering case. |
1108.5599 | Andreas Papaefstathiou | Andreas Papaefstathiou | Phenomenological aspects of new physics at high energy hadron colliders | PhD Thesis submitted to the University of Cambridge in April 2011,
examined in May 2011 and approved in July 2011. 225 pages. Abstract shortened
in arXiv submission | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | A general introduction is given in chapter 1. Chapter 2 outlines the main
features of the Standard Model (SM) of particle physics and the theoretical
motivations for going beyond it. We subsequently provide brief descriptions of
a few popular models that aim to solve the issues that arise within the SM. In
chapter 3 we describe the general Monte Carlo method and show how it can be
used to construct a class of computational tools called Monte Carlo event
generators. We describe the main generic features of event generators and how
these are implemented in the HERWIG++ event generator. By applying resummation
techniques, we provide, in chapter 4, analytical calculations of two types of
hadron collider observables: global inclusive variables and the transverse
energy of the QCD initial state radiation (ET), associated with the either
Drell-Yan gauge boson production or Higgs boson production. In both cases we
provide comparisons to results obtained from Monte Carlo event generators. In
chapter 5 we examine two well-motivated models for new physics: one of new
heavy charged vector bosons (W prime) and a model motivated by strong dynamics
electroweak symmetry breaking that contains new resonances, leptoquarks, that
couple primarily to quarks and leptons of the third generation. In the prior
model, we improve the current treatment of the W' by considering interference
effects with the SM W and construct an event generator accurate to
next-to-leading order which we use to conduct a phenomenological analysis. For
the leptoquark model, we provide an implementation in the HERWIG++ event
generator and use it to form a strategy for mass reconstruction.
| [
{
"created": "Mon, 29 Aug 2011 15:20:28 GMT",
"version": "v1"
}
] | 2011-08-30 | [
[
"Papaefstathiou",
"Andreas",
""
]
] | A general introduction is given in chapter 1. Chapter 2 outlines the main features of the Standard Model (SM) of particle physics and the theoretical motivations for going beyond it. We subsequently provide brief descriptions of a few popular models that aim to solve the issues that arise within the SM. In chapter 3 we describe the general Monte Carlo method and show how it can be used to construct a class of computational tools called Monte Carlo event generators. We describe the main generic features of event generators and how these are implemented in the HERWIG++ event generator. By applying resummation techniques, we provide, in chapter 4, analytical calculations of two types of hadron collider observables: global inclusive variables and the transverse energy of the QCD initial state radiation (ET), associated with the either Drell-Yan gauge boson production or Higgs boson production. In both cases we provide comparisons to results obtained from Monte Carlo event generators. In chapter 5 we examine two well-motivated models for new physics: one of new heavy charged vector bosons (W prime) and a model motivated by strong dynamics electroweak symmetry breaking that contains new resonances, leptoquarks, that couple primarily to quarks and leptons of the third generation. In the prior model, we improve the current treatment of the W' by considering interference effects with the SM W and construct an event generator accurate to next-to-leading order which we use to conduct a phenomenological analysis. For the leptoquark model, we provide an implementation in the HERWIG++ event generator and use it to form a strategy for mass reconstruction. |
1903.01883 | Shuntaro Sakai | Wei-Hong Liang, S. Sakai and E. Oset | Theoretical description of the $\boldsymbol{J/\psi \to \eta (\eta')
h_1(1380)}$, $\boldsymbol{J/\psi \to \eta (\eta') h_1(1170)}$ and
$\boldsymbol{J/\psi \to \pi^0 b_1(1235)^0}$ reactions | 21 pages, 6 figures | Phys. Rev. D 99, 094020 (2019) | 10.1103/PhysRevD.99.094020 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We have made a study of the $J/\psi \to \eta' h_1, \eta h_1$ (with $h_1$
being $h_1(1170)$ and $h_1(1380)$) and $J/\psi \to \pi^0 b_1(1235)^0$ assuming
the axial vector mesons to be dynamically generated from the
pseudoscalar-vector meson interaction. We have taken the needed input from
previous studies of the $J/\psi \to \phi \pi \pi, \omega \pi \pi$ reactions.
We obtain fair agreement with experimental data and provide an explanation on
why the recent experiment on $J/\psi \to \eta' h_1(1380), h_1(1380) \to K^{*+}
K^- +c.c.$ observed in the $K^+ K^- \pi^0$ mode observes the peak of the
$h_1(1380)$ at a higher energy than its nominal mass.
| [
{
"created": "Tue, 5 Mar 2019 15:10:19 GMT",
"version": "v1"
}
] | 2019-05-22 | [
[
"Liang",
"Wei-Hong",
""
],
[
"Sakai",
"S.",
""
],
[
"Oset",
"E.",
""
]
] | We have made a study of the $J/\psi \to \eta' h_1, \eta h_1$ (with $h_1$ being $h_1(1170)$ and $h_1(1380)$) and $J/\psi \to \pi^0 b_1(1235)^0$ assuming the axial vector mesons to be dynamically generated from the pseudoscalar-vector meson interaction. We have taken the needed input from previous studies of the $J/\psi \to \phi \pi \pi, \omega \pi \pi$ reactions. We obtain fair agreement with experimental data and provide an explanation on why the recent experiment on $J/\psi \to \eta' h_1(1380), h_1(1380) \to K^{*+} K^- +c.c.$ observed in the $K^+ K^- \pi^0$ mode observes the peak of the $h_1(1380)$ at a higher energy than its nominal mass. |
hep-ph/0303035 | Radhey Shyam | R. Shyam and U. Mosel | Role of baryonic resonances in the dilepton emission in nucleon-nucleon
collisions | 22 pages, 7 figures, more details of the calculations added, version
to appear in Phys. Rev C | Phys.Rev. C67 (2003) 065202 | 10.1103/PhysRevC.67.065202 | null | hep-ph nucl-ex nucl-th | null | Within an effective Lagrangian model, we present calculations for cross
sections of the dilepton production in proton-proton and proton-neutron
collisions at laboratory kinetic energies in 1-5 GeV range. Production
amplitudes include contributions from the nucleon-nucleon bremsstrahlung as
well as from the mechanism of excitation, propagation, and radiative decay of
Delta(1232) and N*(1520) intermediate baryonic resonances. It is found that the
delta isobar terms dominate the cross sections in the entire considered beam
energy range. Our calculations are able to explain the data of the DLS
collaboration on the dilepton production in proton-proton collisions for beam
energies below 1.3 GeV. However, for incident energies higher than this the
inclusion of contributions from other dilepton sources like Dalitz decay of pi0
and eta mesons, and direct decay of rho and omega mesons is necessary to
describe the data.
| [
{
"created": "Wed, 5 Mar 2003 13:58:39 GMT",
"version": "v1"
},
{
"created": "Fri, 9 May 2003 14:45:39 GMT",
"version": "v2"
}
] | 2009-11-10 | [
[
"Shyam",
"R.",
""
],
[
"Mosel",
"U.",
""
]
] | Within an effective Lagrangian model, we present calculations for cross sections of the dilepton production in proton-proton and proton-neutron collisions at laboratory kinetic energies in 1-5 GeV range. Production amplitudes include contributions from the nucleon-nucleon bremsstrahlung as well as from the mechanism of excitation, propagation, and radiative decay of Delta(1232) and N*(1520) intermediate baryonic resonances. It is found that the delta isobar terms dominate the cross sections in the entire considered beam energy range. Our calculations are able to explain the data of the DLS collaboration on the dilepton production in proton-proton collisions for beam energies below 1.3 GeV. However, for incident energies higher than this the inclusion of contributions from other dilepton sources like Dalitz decay of pi0 and eta mesons, and direct decay of rho and omega mesons is necessary to describe the data. |
2209.00369 | Diogo Boito | D. Boito, G. das Neves, J. Piclum | $H\to \gamma\gamma$ to all orders in $\alpha_s$ in the large-$\beta_0$
limit of QCD | 15 pages, 3 figures. Extended results to include the first two terms
in the heavy-top expansion. Matches published version | Phys.Rev. D 106 (2022) 9, 094026 | 10.1103/PhysRevD.106.094026 | SI-HEP-2022-25, P3H-22-093 | hep-ph | http://creativecommons.org/licenses/by/4.0/ | In this note, we present the result for the QCD corrections to the decay of
the Higgs boson into two photons in the large-$\beta_0$ limit of QCD, providing
the first two terms in the heavy-top expansion. From our results, one can
easily read off the exact leading-$n_f$ QCD contributions in analytic form to
all orders in the strong coupling, $\alpha_s$, where $n_f$ is the number of
massless quarks, and identify the leading renormalon singularities. We give
explicit results for the leading-$n_f$ coefficients at 6 and 7 loops and use
the large-$\beta_0$ result to speculate about the size of yet unknown (but
small) higher-order contributions to the QCD series.
| [
{
"created": "Thu, 1 Sep 2022 11:27:13 GMT",
"version": "v1"
},
{
"created": "Wed, 7 Dec 2022 01:11:15 GMT",
"version": "v2"
}
] | 2022-12-08 | [
[
"Boito",
"D.",
""
],
[
"Neves",
"G. das",
""
],
[
"Piclum",
"J.",
""
]
] | In this note, we present the result for the QCD corrections to the decay of the Higgs boson into two photons in the large-$\beta_0$ limit of QCD, providing the first two terms in the heavy-top expansion. From our results, one can easily read off the exact leading-$n_f$ QCD contributions in analytic form to all orders in the strong coupling, $\alpha_s$, where $n_f$ is the number of massless quarks, and identify the leading renormalon singularities. We give explicit results for the leading-$n_f$ coefficients at 6 and 7 loops and use the large-$\beta_0$ result to speculate about the size of yet unknown (but small) higher-order contributions to the QCD series. |
1604.01102 | Pedro Cavalcanti Malta | Y.M.P. Gomes and P.C. Malta | Lab-based limits on the Carroll-Field-Jackiw Lorentz-violating
electrodynamics | Reviewed version in two columns (8 pages, 1 figure): small
corrections. Matches the version accepted for publication (Phys. Rev. D) | Phys. Rev. D 94, 025031 (2016) | 10.1103/PhysRevD.94.025031 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The CPT-odd and Lorentz-violating Carroll-Field-Jackiw modification of
electrodynamics is discussed and we study its effects on the energy spectrum of
hydrogen, as well as in the generation of a momentum-dependent electric dipole
moment for charged leptons. We also briefly comment on the possibility of the
detection of Lorentz violation in measurements of vacuum birefringence in
resonant cavities. The bounds found are based on local laboratory experimental
limits and are not competitive with the ones coming from astrophysical
considerations.
| [
{
"created": "Tue, 5 Apr 2016 00:58:30 GMT",
"version": "v1"
},
{
"created": "Tue, 10 May 2016 20:05:19 GMT",
"version": "v2"
},
{
"created": "Tue, 24 May 2016 22:30:27 GMT",
"version": "v3"
},
{
"created": "Mon, 11 Jul 2016 11:14:47 GMT",
"version": "v4"
}
] | 2016-07-27 | [
[
"Gomes",
"Y. M. P.",
""
],
[
"Malta",
"P. C.",
""
]
] | The CPT-odd and Lorentz-violating Carroll-Field-Jackiw modification of electrodynamics is discussed and we study its effects on the energy spectrum of hydrogen, as well as in the generation of a momentum-dependent electric dipole moment for charged leptons. We also briefly comment on the possibility of the detection of Lorentz violation in measurements of vacuum birefringence in resonant cavities. The bounds found are based on local laboratory experimental limits and are not competitive with the ones coming from astrophysical considerations. |
hep-ph/9710339 | Andre Likhoded | A.V.Berezhnoy, V.V.Kiselev, A.K.Likhoded, A.I.Onishchenko | Doubly Charmed Baryon Production in Hadronic Experiments | 30 pages, epsf-style, 12 figures | Phys.Rev. D57 (1998) 4385-4392 | 10.1103/PhysRevD.57.4385 | IHEP 97-37 | hep-ph | null | In the leading order of perturbative QCD one calculates the total and
differential cross-sections for the hadronic production of doubly charmed
baryons $\Xi_{cc}$ and $\Xi_{cc}^*$ in different experiments. The experimental
evaluation of cross-sections for the $J/\Psi +D + \bar D$ production would
allow one to decrease the uncertainty in the determination of cross-sections
for the doubly charmed baryons due to the choice of $\alpha_s$ and $m_c$. One
shows that in the HERA-B and E781 experiments with fixed tagets the suppression
of the $\Xi_{cc}$ and $\Xi_{cc}^*$ production to the yield of $c \bar c$-pairs
is the value of the order of $10^{-6}-10^{-5}$, whereas at the TEVATRON and LHC
colliders it is about $10^{-4}-10^{-3}$. In the E781 experiment the observation
of $\Xi_{cc}$ and $\Xi_{cc}^*$ is practically unpossible. At the HERA-B and
TEVATRON facilities one can expect $10^5$ events with the double charm, and at
LHC one has about $10^9$ ones.
| [
{
"created": "Tue, 14 Oct 1997 06:02:07 GMT",
"version": "v1"
}
] | 2009-10-30 | [
[
"Berezhnoy",
"A. V.",
""
],
[
"Kiselev",
"V. V.",
""
],
[
"Likhoded",
"A. K.",
""
],
[
"Onishchenko",
"A. I.",
""
]
] | In the leading order of perturbative QCD one calculates the total and differential cross-sections for the hadronic production of doubly charmed baryons $\Xi_{cc}$ and $\Xi_{cc}^*$ in different experiments. The experimental evaluation of cross-sections for the $J/\Psi +D + \bar D$ production would allow one to decrease the uncertainty in the determination of cross-sections for the doubly charmed baryons due to the choice of $\alpha_s$ and $m_c$. One shows that in the HERA-B and E781 experiments with fixed tagets the suppression of the $\Xi_{cc}$ and $\Xi_{cc}^*$ production to the yield of $c \bar c$-pairs is the value of the order of $10^{-6}-10^{-5}$, whereas at the TEVATRON and LHC colliders it is about $10^{-4}-10^{-3}$. In the E781 experiment the observation of $\Xi_{cc}$ and $\Xi_{cc}^*$ is practically unpossible. At the HERA-B and TEVATRON facilities one can expect $10^5$ events with the double charm, and at LHC one has about $10^9$ ones. |
hep-ph/9712469 | Nikolai N. Nikolaev | J.Nemchik (Inst. Exp. Physics, Kosice), N.N.Nikolaev (IKP, FZ Juelich
& Landau Inst., Moscow), E.Predazzi (Univ. Torino), B.G.Zakharov (Landau
Inst., Moscow) and V.R. Zoller (ITEP, Moscow) | The diffraction cone for exclusive vector meson production in deep
inelastic scattering | 36 pages, 19 figures | J.Exp.Theor.Phys. 86 (1998) 1054-1073; Zh.Eksp.Teor.Fiz. 113
(1998) 1930-1962 | 10.1134/1.558573 | FZ-IKP-97-23 | hep-ph | null | We develop the color dipole gBFKL phenomenology of a diffraction cone for
photo- and electroproduction $\gamma^{*}N \to VN$ of heavy vector mesons
(charmonium & bottonium) at HERA and in fixed target experiments. We predict a
substantial shrinkage of the diffraction cone from the CERN/FNAL to the HERA
range of c.m.s. energy $W$. The $Q^{2}$-controlled selectivity to the color
dipole size (scanning phenomenon) is shown to lead to a decrease of the
diffraction slope with $Q^{2}$ (which is supported by the available
experimental data). We predict an approximate flavor independence of the
diffraction slope in the scaling variable $Q^{2}+m_{V}^{2}$. For diffractive
production of the radially excited $2S$ states ($\Psi',\Upsilon'$) the
counterintuitive inequality of diffraction slopes $B(2S) \lsim B(1S)$ is
predicted, which defies the common wisdom that diffraction slopes are larger
for reactions with larger size particles.
| [
{
"created": "Sat, 20 Dec 1997 18:54:49 GMT",
"version": "v1"
}
] | 2009-10-30 | [
[
"Nemchik",
"J.",
"",
"Inst. Exp. Physics, Kosice"
],
[
"Nikolaev",
"N. N.",
"",
"IKP, FZ Juelich\n & Landau Inst., Moscow"
],
[
"Predazzi",
"E.",
"",
"Univ. Torino"
],
[
"Zakharov",
"B. G.",
"",
"Landau\n Inst., Moscow"
],
[
"Zoller",
"V. R.",
"",
"ITEP, Moscow"
]
] | We develop the color dipole gBFKL phenomenology of a diffraction cone for photo- and electroproduction $\gamma^{*}N \to VN$ of heavy vector mesons (charmonium & bottonium) at HERA and in fixed target experiments. We predict a substantial shrinkage of the diffraction cone from the CERN/FNAL to the HERA range of c.m.s. energy $W$. The $Q^{2}$-controlled selectivity to the color dipole size (scanning phenomenon) is shown to lead to a decrease of the diffraction slope with $Q^{2}$ (which is supported by the available experimental data). We predict an approximate flavor independence of the diffraction slope in the scaling variable $Q^{2}+m_{V}^{2}$. For diffractive production of the radially excited $2S$ states ($\Psi',\Upsilon'$) the counterintuitive inequality of diffraction slopes $B(2S) \lsim B(1S)$ is predicted, which defies the common wisdom that diffraction slopes are larger for reactions with larger size particles. |
1403.6217 | Bhaskar Dutta | Bhaskar Dutta | Dark Matter Searches at Accelerator Facilities | 26 pages, 15 figures, Plenary talk at the Symposium on Cosmology and
Particle Astrophysics 2013 Honolulu, HI, November 12- 15, 2013 | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | About 80 percent of the matter content of the universe is dark matter.
However, the particle origin of dark matter is yet to be established. Many
extensions of the Standard Model (SM) contain candidates of dark matter. The
search for the particle origin is currently ongoing at the large hadron
collider (LHC). In this review, I will summarize the different search
strategies for this elusive particle.
| [
{
"created": "Tue, 25 Mar 2014 03:00:46 GMT",
"version": "v1"
}
] | 2014-03-26 | [
[
"Dutta",
"Bhaskar",
""
]
] | About 80 percent of the matter content of the universe is dark matter. However, the particle origin of dark matter is yet to be established. Many extensions of the Standard Model (SM) contain candidates of dark matter. The search for the particle origin is currently ongoing at the large hadron collider (LHC). In this review, I will summarize the different search strategies for this elusive particle. |
1212.3310 | Diego Aristizabal | D. Aristizabal Sierra, D. Restrepo, S. Spinner | LSP sneutrino decays into heavy standard model pairs | 26 pages, 8 figures. Different-flavor charged lepton modes included
and their relevance discussed. Several plots updated to include these
channels. New plot for sneutrino absolute decay branching ratios added.
Conclusions unchanged. Version matches publication in JHEP (title changed in
journal) | null | 10.1007/JHEP05(2013)046 | null | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In bilinear R-parity violation (BRpV), in which the superpotential includes a
bilinear term between the lepton doublet and the up-type Higgs superfields, a
sneutrino LSP can decay into pairs of heavy standard model states: W's, Z's,
tops or Higgs bosons. These finals states can dominate over the traditionally
considered bottom pair final state. This would lead to unique and novel
supersymmetric signals with each supersymmetric event possibly producing two
pairs of these heavy standard model fields. We investigate this possibility and
find that the branching ratio into heavier states dominates when the bilinear
term is much smaller than the sneutrino vacuum expectation value for a given
sneutrino flavor. When BRpV is the only source of neutrino masses these decays
can only dominate for one of the sneutrino generations. Relaxing this
constraint opens these channels for all three generations.
| [
{
"created": "Thu, 13 Dec 2012 20:35:40 GMT",
"version": "v1"
},
{
"created": "Mon, 19 May 2014 15:54:57 GMT",
"version": "v2"
}
] | 2014-05-20 | [
[
"Sierra",
"D. Aristizabal",
""
],
[
"Restrepo",
"D.",
""
],
[
"Spinner",
"S.",
""
]
] | In bilinear R-parity violation (BRpV), in which the superpotential includes a bilinear term between the lepton doublet and the up-type Higgs superfields, a sneutrino LSP can decay into pairs of heavy standard model states: W's, Z's, tops or Higgs bosons. These finals states can dominate over the traditionally considered bottom pair final state. This would lead to unique and novel supersymmetric signals with each supersymmetric event possibly producing two pairs of these heavy standard model fields. We investigate this possibility and find that the branching ratio into heavier states dominates when the bilinear term is much smaller than the sneutrino vacuum expectation value for a given sneutrino flavor. When BRpV is the only source of neutrino masses these decays can only dominate for one of the sneutrino generations. Relaxing this constraint opens these channels for all three generations. |
hep-ph/9603326 | null | Edmond L. Berger and Harry Contopanagos (Argonne) | The Perturbative Resummed Series for Top Quark Production in Hadron
Reactions | 61 pages, LaTeX, plus 21 postscript figures; Fig. 1a inadvertently
omitted from the March 15 submission is now included | Phys.Rev. D54 (1996) 3085-3113 | 10.1103/PhysRevD.54.3085 | ANL-HEP-PR-95-82 | hep-ph | null | Our calculation of the total cross section for inclusive production of
$t\bar{t}$ pairs in hadron collisions is presented. The principal ingredient of
the calculation is resummation of the universal leading-logarithm effects of
gluon radiation to all orders in the quantum chromodynamics coupling strength,
restricted to the region of phase space that is demonstrably perturbative. We
derive the perturbative regime of the resummed series, starting from the
principal-value resummation approach, and we isolate the perturbative domain in
both moment space and, upon inversion of the corresponding Mellin transform, in
momentum space. We show that our perturbative result does not depend on the
manner non-perturbative or infrared effects are handled in principal-value
resummation. We treat both the quark-antiquark and gluon-gluon production
channels consistently in the $\overline{{\rm MS}}$ factorization scheme. We
compare our method and results with other resummation methods that rely on the
choice of infrared cutoffs. We derive the renormalization/factorization scale
dependence of our resummed cross section, and we discuss factorization scheme
dependence and remaining theoretical uncertainties, including estimates of
possible non-perturbative contributions. We include the full content of the
exact next-to-leading order calculation in obtaining our final results. We
present predictions of the physical cross section as a function of top quark
mass in proton-antiproton reactions at center-of-mass energies of 1.8 and 2.0
TeV. We also provide the differential cross section as a function of the
parton-parton subenergy.
| [
{
"created": "Sat, 16 Mar 1996 02:51:58 GMT",
"version": "v1"
},
{
"created": "Mon, 18 Mar 1996 19:24:13 GMT",
"version": "v2"
}
] | 2009-10-28 | [
[
"Berger",
"Edmond L.",
"",
"Argonne"
],
[
"Contopanagos",
"Harry",
"",
"Argonne"
]
] | Our calculation of the total cross section for inclusive production of $t\bar{t}$ pairs in hadron collisions is presented. The principal ingredient of the calculation is resummation of the universal leading-logarithm effects of gluon radiation to all orders in the quantum chromodynamics coupling strength, restricted to the region of phase space that is demonstrably perturbative. We derive the perturbative regime of the resummed series, starting from the principal-value resummation approach, and we isolate the perturbative domain in both moment space and, upon inversion of the corresponding Mellin transform, in momentum space. We show that our perturbative result does not depend on the manner non-perturbative or infrared effects are handled in principal-value resummation. We treat both the quark-antiquark and gluon-gluon production channels consistently in the $\overline{{\rm MS}}$ factorization scheme. We compare our method and results with other resummation methods that rely on the choice of infrared cutoffs. We derive the renormalization/factorization scale dependence of our resummed cross section, and we discuss factorization scheme dependence and remaining theoretical uncertainties, including estimates of possible non-perturbative contributions. We include the full content of the exact next-to-leading order calculation in obtaining our final results. We present predictions of the physical cross section as a function of top quark mass in proton-antiproton reactions at center-of-mass energies of 1.8 and 2.0 TeV. We also provide the differential cross section as a function of the parton-parton subenergy. |
hep-ph/9707253 | Heath O'Connell | A.G. Williams, H.B. O'Connell and A.W. Thomas | On extracting the rho-omega mixing amplitude from the pion form-factor | 8 pages, uses espcrc1.sty (provided in uufile). Talk given at the
Int. Conf. on Quark Lepton Nuclear Physics, Osaka, May 20 - 23, 1997 | Nucl.Phys.A629:464c-470c,1998 | 10.1016/S0375-9474(97)00723-9 | ADP-97-19/T256, UK/97-15 | hep-ph | null | In this paper we improve and extend a recent analysis which showed that the
rho-omega mixing amplitude cannot be unambiguously extracted from the pion
electromagnetic form-factor in a model independent way. In particular, we focus
on the argument that the extraction is sensitive to the presence of any
intrinsic omega_I -> pi pi coupling. Our extended analysis confirms the
original conclusion, with only minor, quantitative differences. The extracted
mixing amplitude is shown to be sensitive to both the intrinsic coupling
omega_I -> pi pi and to the value assumed for the mass of the rho^0-meson.
| [
{
"created": "Sat, 5 Jul 1997 18:52:13 GMT",
"version": "v1"
}
] | 2008-11-26 | [
[
"Williams",
"A. G.",
""
],
[
"O'Connell",
"H. B.",
""
],
[
"Thomas",
"A. W.",
""
]
] | In this paper we improve and extend a recent analysis which showed that the rho-omega mixing amplitude cannot be unambiguously extracted from the pion electromagnetic form-factor in a model independent way. In particular, we focus on the argument that the extraction is sensitive to the presence of any intrinsic omega_I -> pi pi coupling. Our extended analysis confirms the original conclusion, with only minor, quantitative differences. The extracted mixing amplitude is shown to be sensitive to both the intrinsic coupling omega_I -> pi pi and to the value assumed for the mass of the rho^0-meson. |
1009.5961 | Ravi Kuchimanchi | Ravi Kuchimanchi | P/CP Conserving CP/P Violation Solves Strong CP Problem | Added equation 12 for {\theta} -- equivalent to eqn 11 but
independent of light quark basis. 9 pages, 2 figures. Published in Phys Rev D | Phys.Rev.D82:116008,2010 | 10.1103/PhysRevD.82.116008 | null | hep-ph hep-ex hep-lat hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We find a solution to the Strong CP problem that may be testable at the LHC
and future colliders. In this solution CP is broken by parity conserving terms,
while parity breaking VEVs conserve CP. The quark mass matrix is Hermitian at
the tree-level and strong CP phase is generated only in loops where CP and P
violating sectors interact. A full vector-like quark family with parity
symmetric mass-terms that violate CP softly is predicted. Since no Higgs VEVs
(other than the SU(2)_L breaking weak-scale VEV) contribute to the masses of
the new quarks, they can be naturally light, independent of parity breaking and
other high energy scales.
| [
{
"created": "Wed, 29 Sep 2010 18:02:08 GMT",
"version": "v1"
},
{
"created": "Wed, 22 Dec 2010 17:21:52 GMT",
"version": "v2"
}
] | 2011-01-05 | [
[
"Kuchimanchi",
"Ravi",
""
]
] | We find a solution to the Strong CP problem that may be testable at the LHC and future colliders. In this solution CP is broken by parity conserving terms, while parity breaking VEVs conserve CP. The quark mass matrix is Hermitian at the tree-level and strong CP phase is generated only in loops where CP and P violating sectors interact. A full vector-like quark family with parity symmetric mass-terms that violate CP softly is predicted. Since no Higgs VEVs (other than the SU(2)_L breaking weak-scale VEV) contribute to the masses of the new quarks, they can be naturally light, independent of parity breaking and other high energy scales. |
1812.08750 | Richard Ruiz | Silvia Pascoli, Richard Ruiz, Cedric Weiland | Heavy Neutrinos with Dynamic Jet Vetoes: Multilepton Searches at
$\sqrt{s} = 14,~27,$ and $100$ TeV | Journal version, results unchanged: 101 pages, 26 figures (116 eps
files), 8 tables. Dirac neutrino FeynRules model libraries available from
https://feynrules.irmp.ucl.ac.be/wiki/HeavyN | JHEP 1906 (2019) 049 | 10.1007/JHEP06(2019)049 | CP3-18-77, IPPP/18/111, PITT-PACC-1821, VBSCAN-PUB-10-18 | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Heavy neutrinos $(N)$ remain one of most promising explanations for the
origin of neutrinos' tiny masses and large mixing angles. In light of broad
advances in understanding and modeling of hadron collisions at large momentum
transfer, we revisit the long-standard search strategy for heavy $N$ decaying
to multiple charged leptons $(\ell)$, $pp \to N\ell X \to 3\ell \nu X$. For
electroweak and TeV-scale $N$, we propose a qualitatively new collider analysis
premised on a dynamic jet veto and discriminating, on an event-by-event basis,
according to the relative amount of hadronic and leptonic activity. We report
that the sensitivity to $N$ at the Large Hadron Collider (LHC) can be improved
by roughly an order of magnitude over the collider's lifetime. At $\sqrt{s}=14$
TeV with $\mathcal{L}=3~{\rm ab}^{-1}$, active-sterile mixing as small as
$\vert V_{\ell N}\vert^2 = 10^{-2} ~(10^{-3})~[5\times10^{-4}]$ can be probed
at $95\%$ CL for Dirac neutrinos masses $m_N \lesssim 1200~(300)~[200]$ GeV,
well beyond present constraints for such heavy states. The improvement holds
also for Majorana $N$, and is largely independent of whether charged lepton
flavor is conserved or violated. The analysis, built almost entirely from
inclusive, transverse observables, is designed to be robust across increasing
collider energies, and hence serves as a basis for searches at future
colliders: With $\mathcal{L}=15~{\rm ab}^{-1}$ at $\sqrt{s}=27$ TeV, one can
probe mixing below $\vert V_{\ell N}\vert^2 = 10^{-2}
~(10^{-3})~[2\times10^{-4}]$ for $m_N \lesssim 3500~(700)~[200]$ GeV. At a
hypothetical 100 TeV $pp$ collider with $\mathcal{L}=30~{\rm ab}^{-1}$, one can
probe below $\vert V_{\ell N}\vert^2 = 9\times10^{-5}~(10^{-3})~[10^{-2}]$ for
$m_N \lesssim 200$ GeV ($4$ TeV) [$15$ TeV]. We anticipate these results can be
further improved with detector-specific tuning and application of machines
learning techniques.
| [
{
"created": "Thu, 20 Dec 2018 18:31:47 GMT",
"version": "v1"
},
{
"created": "Thu, 27 Jun 2019 12:45:53 GMT",
"version": "v2"
}
] | 2019-06-28 | [
[
"Pascoli",
"Silvia",
""
],
[
"Ruiz",
"Richard",
""
],
[
"Weiland",
"Cedric",
""
]
] | Heavy neutrinos $(N)$ remain one of most promising explanations for the origin of neutrinos' tiny masses and large mixing angles. In light of broad advances in understanding and modeling of hadron collisions at large momentum transfer, we revisit the long-standard search strategy for heavy $N$ decaying to multiple charged leptons $(\ell)$, $pp \to N\ell X \to 3\ell \nu X$. For electroweak and TeV-scale $N$, we propose a qualitatively new collider analysis premised on a dynamic jet veto and discriminating, on an event-by-event basis, according to the relative amount of hadronic and leptonic activity. We report that the sensitivity to $N$ at the Large Hadron Collider (LHC) can be improved by roughly an order of magnitude over the collider's lifetime. At $\sqrt{s}=14$ TeV with $\mathcal{L}=3~{\rm ab}^{-1}$, active-sterile mixing as small as $\vert V_{\ell N}\vert^2 = 10^{-2} ~(10^{-3})~[5\times10^{-4}]$ can be probed at $95\%$ CL for Dirac neutrinos masses $m_N \lesssim 1200~(300)~[200]$ GeV, well beyond present constraints for such heavy states. The improvement holds also for Majorana $N$, and is largely independent of whether charged lepton flavor is conserved or violated. The analysis, built almost entirely from inclusive, transverse observables, is designed to be robust across increasing collider energies, and hence serves as a basis for searches at future colliders: With $\mathcal{L}=15~{\rm ab}^{-1}$ at $\sqrt{s}=27$ TeV, one can probe mixing below $\vert V_{\ell N}\vert^2 = 10^{-2} ~(10^{-3})~[2\times10^{-4}]$ for $m_N \lesssim 3500~(700)~[200]$ GeV. At a hypothetical 100 TeV $pp$ collider with $\mathcal{L}=30~{\rm ab}^{-1}$, one can probe below $\vert V_{\ell N}\vert^2 = 9\times10^{-5}~(10^{-3})~[10^{-2}]$ for $m_N \lesssim 200$ GeV ($4$ TeV) [$15$ TeV]. We anticipate these results can be further improved with detector-specific tuning and application of machines learning techniques. |
1909.13802 | Jose Rodriguez-Quintero | Jos\'e Rodr\'iguez-Quintero, Lei Chang, Kh\'epani Raya, Craig D.
Roberts | Process-independent effective coupling and the pion structure function | INPC 2019 proceedings | null | 10.1088/1742-6596/1643/1/012177 | null | hep-ph nucl-ex nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We sketch the calculation of the pion structure functions within the DSE
framework, following two alternative albeit consistent approaches, and discuss
then their QCD evolution, the running driven by an effective charge, from a
hadronic scale up to any larger one accessible to experiment.
| [
{
"created": "Mon, 30 Sep 2019 15:55:37 GMT",
"version": "v1"
}
] | 2021-02-03 | [
[
"Rodríguez-Quintero",
"José",
""
],
[
"Chang",
"Lei",
""
],
[
"Raya",
"Khépani",
""
],
[
"Roberts",
"Craig D.",
""
]
] | We sketch the calculation of the pion structure functions within the DSE framework, following two alternative albeit consistent approaches, and discuss then their QCD evolution, the running driven by an effective charge, from a hadronic scale up to any larger one accessible to experiment. |
0811.0775 | Akaki Rusetsky | Gilberto Colangelo (University of Bern), Juerg Gasser (University of
Bern), Akaki Rusetsky (University of Bonn) | Isospin breaking in Kl4 decays | 33 pages, 12 figures | Eur.Phys.J.C59:777-793,2009 | 10.1140/epjc/s10052-008-0818-9 | HISKP-TH-08/13 | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Data on Ke4 decays allow one to extract experimental information on the
elastic pi pi scattering amplitude near threshold, and to confront the outcome
of the analysis with predictions made in the framework of QCD. These
predictions concern an isospin symmetric world, while experiments are carried
out in the real world, where isospin breaking effects - generated by
electromagnetic interactions and by the mass difference of the up and down
quarks - are always present. We discuss the corrections required to account for
these, so that a meaningful comparison with the predictions becomes possible.
In particular, we note that there is a spectacular isospin breaking effect in
Ke4 decays. Once it is taken into account, the previous discrepancy between
NA48/2 data on Ke4 decays and the prediction of pi pi scattering lengths
disappears.
| [
{
"created": "Wed, 5 Nov 2008 17:48:59 GMT",
"version": "v1"
}
] | 2009-05-20 | [
[
"Colangelo",
"Gilberto",
"",
"University of Bern"
],
[
"Gasser",
"Juerg",
"",
"University of\n Bern"
],
[
"Rusetsky",
"Akaki",
"",
"University of Bonn"
]
] | Data on Ke4 decays allow one to extract experimental information on the elastic pi pi scattering amplitude near threshold, and to confront the outcome of the analysis with predictions made in the framework of QCD. These predictions concern an isospin symmetric world, while experiments are carried out in the real world, where isospin breaking effects - generated by electromagnetic interactions and by the mass difference of the up and down quarks - are always present. We discuss the corrections required to account for these, so that a meaningful comparison with the predictions becomes possible. In particular, we note that there is a spectacular isospin breaking effect in Ke4 decays. Once it is taken into account, the previous discrepancy between NA48/2 data on Ke4 decays and the prediction of pi pi scattering lengths disappears. |
1812.01585 | Sebastian Baum | Sebastian Baum, Riccardo Catena, Martin B. Krauss | Constraints on New Scalar and Vector Mediators from LHC Dijet Searches | 34 pages, 8 figures, 4 tables. v3: matches the published version | J. Phys. G: Nucl. Part. Phys. 47 (2020) 055001 | 10.1088/1361-6471/ab6949 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present a reanalysis of the latest results from CMS dijet searches for an
integrated luminosity of $36\,$fb$^{-1}$ together with preliminary results for
$78\,$fb$^{-1}$ in the framework of simplified models for dark matter
interacting with quarks through the exchange of a scalar, pseudoscalar, vector
or pseudovector mediator particle. Within the same framework, we also project
the sensitivity of dijet searches in future LHC runs and study how well the
parameters of a simplified model could be reconstructed in case of a future
discovery at the high luminosity (HL) LHC. Finally, we explore the possibility
of discriminating different mediator scenarios by extending the sensitivity of
dijet searches for simplified models through the use of angular information. It
is the first time that these studies are performed systematically for the case
of spin 0 mediators. Among other results we find: 1) no evidence for a dijet
signal in the simplified model framework; 2) improvements due to an increased
luminosity at the HL-LHC are significant, but mostly for heavy mediators, where
dijet searches are limited by statistical, rather than systematical
uncertainties; 3) Information on the angular separation of dijets could be used
at the HL-LHC to discriminate different mediator scenarios.
| [
{
"created": "Tue, 4 Dec 2018 18:41:19 GMT",
"version": "v1"
},
{
"created": "Mon, 4 Nov 2019 18:26:21 GMT",
"version": "v2"
},
{
"created": "Wed, 11 Mar 2020 12:43:05 GMT",
"version": "v3"
}
] | 2020-03-12 | [
[
"Baum",
"Sebastian",
""
],
[
"Catena",
"Riccardo",
""
],
[
"Krauss",
"Martin B.",
""
]
] | We present a reanalysis of the latest results from CMS dijet searches for an integrated luminosity of $36\,$fb$^{-1}$ together with preliminary results for $78\,$fb$^{-1}$ in the framework of simplified models for dark matter interacting with quarks through the exchange of a scalar, pseudoscalar, vector or pseudovector mediator particle. Within the same framework, we also project the sensitivity of dijet searches in future LHC runs and study how well the parameters of a simplified model could be reconstructed in case of a future discovery at the high luminosity (HL) LHC. Finally, we explore the possibility of discriminating different mediator scenarios by extending the sensitivity of dijet searches for simplified models through the use of angular information. It is the first time that these studies are performed systematically for the case of spin 0 mediators. Among other results we find: 1) no evidence for a dijet signal in the simplified model framework; 2) improvements due to an increased luminosity at the HL-LHC are significant, but mostly for heavy mediators, where dijet searches are limited by statistical, rather than systematical uncertainties; 3) Information on the angular separation of dijets could be used at the HL-LHC to discriminate different mediator scenarios. |
2003.08391 | Daniele Barducci | Daniele Barducci, Enrico Bertuzzo, Andrea Caputo, Pilar Hernandez | Minimal flavor violation in the see-saw portal | 28 pages, 3 Figures. References added, typos corrected. Added
clarification on the contraction of the flavor indices. Matches the published
version | null | 10.1007/JHEP06(2020)185 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We consider an extension of the Standard Model with two singlet leptons, with
masses in the electroweak range, that induce neutrino masses via the see-saw
mechanism, plus a generic new physics sector at a higher scale, $\Lambda$. We
apply the minimal flavor violation (MFV) principle to the corresponding
Effective Field Theory ($\nu$SMEFT) valid at energy scales $E \ll \Lambda$. We
identify the irreducible sources of lepton flavor and lepton number violation
at the renormalizable level, and apply the MFV ans\"atz to derive the scaling
of the Wilson coefficients of the $\nu$SMEFT operators up to dimension six. We
highlight the most important phenomenological consequences of this hypothesis
in the rates for exotic Higgs decays, the decay length of the heavy neutrinos,
and their production modes at present and future colliders. We also comment on
possible astrophysical implications.
| [
{
"created": "Wed, 18 Mar 2020 18:00:01 GMT",
"version": "v1"
},
{
"created": "Tue, 7 Jul 2020 18:16:21 GMT",
"version": "v2"
}
] | 2020-07-15 | [
[
"Barducci",
"Daniele",
""
],
[
"Bertuzzo",
"Enrico",
""
],
[
"Caputo",
"Andrea",
""
],
[
"Hernandez",
"Pilar",
""
]
] | We consider an extension of the Standard Model with two singlet leptons, with masses in the electroweak range, that induce neutrino masses via the see-saw mechanism, plus a generic new physics sector at a higher scale, $\Lambda$. We apply the minimal flavor violation (MFV) principle to the corresponding Effective Field Theory ($\nu$SMEFT) valid at energy scales $E \ll \Lambda$. We identify the irreducible sources of lepton flavor and lepton number violation at the renormalizable level, and apply the MFV ans\"atz to derive the scaling of the Wilson coefficients of the $\nu$SMEFT operators up to dimension six. We highlight the most important phenomenological consequences of this hypothesis in the rates for exotic Higgs decays, the decay length of the heavy neutrinos, and their production modes at present and future colliders. We also comment on possible astrophysical implications. |
1509.01597 | Dorival Goncalves | Dorival Goncalves, Frank Krauss, Silvan Kuttimalai, Philipp
Maierh\"ofer | Higgs-Strahlung: Merging the NLO Drell-Yan and Loop-Induced 0+1 jet
Multiplicities | 13 pages, 12 figures and 3 tables | Phys. Rev. D 92, 073006 (2015) | 10.1103/PhysRevD.92.073006 | IPPP/15/57, DCPT/15/114 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We analyse the production of a Higgs boson in association with a Z boson at
hadron colliders in the Standard Model and some simple extensions. We show how
multi-jet merging algorithms at leading and next-to-leading order for the
loop-induced gluon fusion and the Drell-Yan like quark-induced processes,
respectively, improve the descriptions for various differential distributions,
in particular those that involve the production of additional jets. The
phenomenological studies focus on two relevant channels of Higgs boson decays,
namely $H\rightarrow invisible$ and $H\rightarrow b\bar{b}$. We find sizable
and phenomenologically relevant corrections to the transverse momentum and
invariant mass distributions for the Higgs boson candidate. Thanks to the large
destructive interference for the top Yukawa terms, this process is very
sensitive to the magnitude and sign of a possible non-standard top-Higgs
coupling. We analyse the impact of this anomalous interaction on distributions
and estimate constraints from LHC Run II.
| [
{
"created": "Fri, 4 Sep 2015 20:21:51 GMT",
"version": "v1"
}
] | 2015-10-14 | [
[
"Goncalves",
"Dorival",
""
],
[
"Krauss",
"Frank",
""
],
[
"Kuttimalai",
"Silvan",
""
],
[
"Maierhöfer",
"Philipp",
""
]
] | We analyse the production of a Higgs boson in association with a Z boson at hadron colliders in the Standard Model and some simple extensions. We show how multi-jet merging algorithms at leading and next-to-leading order for the loop-induced gluon fusion and the Drell-Yan like quark-induced processes, respectively, improve the descriptions for various differential distributions, in particular those that involve the production of additional jets. The phenomenological studies focus on two relevant channels of Higgs boson decays, namely $H\rightarrow invisible$ and $H\rightarrow b\bar{b}$. We find sizable and phenomenologically relevant corrections to the transverse momentum and invariant mass distributions for the Higgs boson candidate. Thanks to the large destructive interference for the top Yukawa terms, this process is very sensitive to the magnitude and sign of a possible non-standard top-Higgs coupling. We analyse the impact of this anomalous interaction on distributions and estimate constraints from LHC Run II. |
0805.0385 | Richard Neufeld Jr. | R. B. Neufeld | Fast partons as a source of energy and momentum in a perturbative
quark-gluon plasma | As accepted for publication in Phys Rev D. Introduction is
significantly expanded, some corrections made | Phys.Rev.D78:085015,2008 | 10.1103/PhysRevD.78.085015 | null | hep-ph nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | I derive the space-time distribution of energy and momentum deposited by a
fast parton traversing a perturbative quark-gluon plasma by considering the
fast parton as the source of an external color field interacting with the
medium. I include the medium's response to screen the fast parton's color field
by incorporating dielectric functions and compare to the unscreened result.
| [
{
"created": "Mon, 5 May 2008 14:42:32 GMT",
"version": "v1"
},
{
"created": "Thu, 24 Jul 2008 14:48:38 GMT",
"version": "v2"
},
{
"created": "Fri, 10 Oct 2008 15:42:27 GMT",
"version": "v3"
}
] | 2008-11-26 | [
[
"Neufeld",
"R. B.",
""
]
] | I derive the space-time distribution of energy and momentum deposited by a fast parton traversing a perturbative quark-gluon plasma by considering the fast parton as the source of an external color field interacting with the medium. I include the medium's response to screen the fast parton's color field by incorporating dielectric functions and compare to the unscreened result. |
2309.15912 | Samuel Bright-Thonney | Samuel Bright-Thonney, Philip Harris, Patrick McCormack, Simon Rothman | Chained Quantile Morphing with Normalizing Flows | 13 pages, 7 figures, 3 tables | null | null | null | hep-ph hep-ex | http://creativecommons.org/licenses/by/4.0/ | Accounting for inaccuracies in Monte Carlo simulations is a crucial step in
any high energy physics analysis. It becomes especially important when training
machine learning models, which can amplify simulation inaccuracies and
introduce large discrepancies and systematic uncertainties when the model is
applied to data. In this paper, we introduce a method to transform simulated
events to better match data using normalizing flows, a class of deep
learning-based density estimation models. Our proposal uses a technique called
chained quantile morphing, which corrects a set of observables by iteratively
shifting each entry according to a conditonal cumulative density function. We
demonstrate the technique on a realistic particle physics dataset, and compare
it to a neural network-based reweighting method. We also introduce a new
contrastive learning technique to correct high dimensional particle-level
inputs, which naively cannot be efficiently corrected with morphing strategies.
| [
{
"created": "Wed, 27 Sep 2023 18:00:03 GMT",
"version": "v1"
}
] | 2023-09-29 | [
[
"Bright-Thonney",
"Samuel",
""
],
[
"Harris",
"Philip",
""
],
[
"McCormack",
"Patrick",
""
],
[
"Rothman",
"Simon",
""
]
] | Accounting for inaccuracies in Monte Carlo simulations is a crucial step in any high energy physics analysis. It becomes especially important when training machine learning models, which can amplify simulation inaccuracies and introduce large discrepancies and systematic uncertainties when the model is applied to data. In this paper, we introduce a method to transform simulated events to better match data using normalizing flows, a class of deep learning-based density estimation models. Our proposal uses a technique called chained quantile morphing, which corrects a set of observables by iteratively shifting each entry according to a conditonal cumulative density function. We demonstrate the technique on a realistic particle physics dataset, and compare it to a neural network-based reweighting method. We also introduce a new contrastive learning technique to correct high dimensional particle-level inputs, which naively cannot be efficiently corrected with morphing strategies. |
0907.3374 | Wojciech Broniowski | Wojciech Broniowski, Alexandr E. Dorokhov, Enrique Ruiz Arriola | Photon interactions and chiral dynamics | 7 pages, 4 figures, contribution to the proceedings of PHOTON 09 | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Twist-2 components of the real and virtual photon distribution amplitudes are
evaluated in several chiral quark models. The results, obtained at the quark
model scale, are then evolved to higher scales, probed in experiments or in
lattice QCD. We also analyze the related form factors and coupling constants.
Our results are a genuine dynamical prediction, following from the chiral
dynamics.
| [
{
"created": "Mon, 20 Jul 2009 11:12:01 GMT",
"version": "v1"
},
{
"created": "Sat, 1 Aug 2009 05:49:26 GMT",
"version": "v2"
}
] | 2009-08-01 | [
[
"Broniowski",
"Wojciech",
""
],
[
"Dorokhov",
"Alexandr E.",
""
],
[
"Arriola",
"Enrique Ruiz",
""
]
] | Twist-2 components of the real and virtual photon distribution amplitudes are evaluated in several chiral quark models. The results, obtained at the quark model scale, are then evolved to higher scales, probed in experiments or in lattice QCD. We also analyze the related form factors and coupling constants. Our results are a genuine dynamical prediction, following from the chiral dynamics. |
1004.1075 | Gerald V. Dunne | Gerald V. Dunne and Alex Kovner | U_A(1) Anomaly at high temperature: the scalar-pseudoscalar splitting in
QCD | 5 pp | Phys.Rev.D82:065014,2010 | 10.1103/PhysRevD.82.065014 | null | hep-ph hep-lat hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We estimate the splitting between the spatial correlation lengths in the
scalar and pseudoscalar channels in QCD at high temperature. The splitting is
due to the contribution of the instanton/anti-instanton chains in the thermal
ensemble, even though instanton contributions to thermodynamic quantities are
suppressed. The splitting vanishes at asymptotically high temperatures as
$\Delta M/M\propto (\Lambda_{QCD}/T)^b$, where $b$ is the beta function
coefficient.
| [
{
"created": "Wed, 7 Apr 2010 12:51:38 GMT",
"version": "v1"
}
] | 2010-11-11 | [
[
"Dunne",
"Gerald V.",
""
],
[
"Kovner",
"Alex",
""
]
] | We estimate the splitting between the spatial correlation lengths in the scalar and pseudoscalar channels in QCD at high temperature. The splitting is due to the contribution of the instanton/anti-instanton chains in the thermal ensemble, even though instanton contributions to thermodynamic quantities are suppressed. The splitting vanishes at asymptotically high temperatures as $\Delta M/M\propto (\Lambda_{QCD}/T)^b$, where $b$ is the beta function coefficient. |
0904.3014 | Paul F. Harrison | P. F. Harrison, D. R. J. Roythorne and W. G. Scott | Is the Unitarity Triangle Right? | Talk given at the International Conference on Particles And Nuclei
(PANIC08), Eilat, Israel, 13th November 2008. 4 pages | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The latest fits to the CKM matrix indicate that alpha=(90.7+4.5-2.9) degrees.
The proximity of alpha to a right-angle raises the question: is it merely
accidental or is it due to some physics beyond the Standard Model? In the
framework of our recently-proposed flavour permutation symmetry, we consider
the similarities between the quark and lepton mixing matrices, V and U, arguing
that the relative smallness of one element in each suggests common constraints.
These constraints link the smallness of V_ub and U_e3 with each other, and with
the approximate mu-tau symmetry observed in leptonic mixing, together with a
prediction of a large Dirac CP phase in both the quark and lepton sectors. In
the quark case, we predict alpha=(89.0\pm 0.2) degrees, in agreement with data
and suggesting that the unitarity triangle is in fact very nearly, but not
exactly right.
| [
{
"created": "Mon, 20 Apr 2009 19:21:47 GMT",
"version": "v1"
}
] | 2009-04-21 | [
[
"Harrison",
"P. F.",
""
],
[
"Roythorne",
"D. R. J.",
""
],
[
"Scott",
"W. G.",
""
]
] | The latest fits to the CKM matrix indicate that alpha=(90.7+4.5-2.9) degrees. The proximity of alpha to a right-angle raises the question: is it merely accidental or is it due to some physics beyond the Standard Model? In the framework of our recently-proposed flavour permutation symmetry, we consider the similarities between the quark and lepton mixing matrices, V and U, arguing that the relative smallness of one element in each suggests common constraints. These constraints link the smallness of V_ub and U_e3 with each other, and with the approximate mu-tau symmetry observed in leptonic mixing, together with a prediction of a large Dirac CP phase in both the quark and lepton sectors. In the quark case, we predict alpha=(89.0\pm 0.2) degrees, in agreement with data and suggesting that the unitarity triangle is in fact very nearly, but not exactly right. |
2206.05038 | Gerrit Bickendorf | Gerrit Bickendorf and Manuel Drees | Constraints on Light Leptophilic Dark Matter Mediators from Decay
Experiments | 18 pages, 8 figures | null | 10.1140/epjc/s10052-022-11128-9 | null | hep-ph | http://creativecommons.org/licenses/by/4.0/ | We study the influence of leptophilic dark matter interactions on decays of
muons and ground state mesons in existing experiments. We consider a secluded
dark sector exclusively interacting with leptons via either a (leptophilic)
scalar or vector mediator. These interactions will therefore influence leptonic
decays and deform the energy spectra. We first study the Michel decay of muons,
$\mu^+\rightarrow e^+\nu_e \bar{\nu}_\mu$, which allow us to constrain the
parameter space reasonably well. Secondly, the rare $\pi^\pm$, $K^\pm$, $D^\pm$
and $D_s^\pm$ decays to $e\nu$ will be considered. Scalar mediators would
remove the Standard Model helicity suppression, so that strong constraints can
be derived. The resulting bounds on the couplings of the light mediators to
electrons and muons still turn out to be somewhat weaker than those from
searches at low--energy $e^+e^-$ colliders and the magnetic moment of the muon,
respectively. Finally, we show that kaon and pion decays basically exclude a
''Co--SIMP'' scenario where a scalar dark matter particle has a dimension--5
coupling to electrons.
| [
{
"created": "Fri, 10 Jun 2022 12:22:20 GMT",
"version": "v1"
}
] | 2023-01-18 | [
[
"Bickendorf",
"Gerrit",
""
],
[
"Drees",
"Manuel",
""
]
] | We study the influence of leptophilic dark matter interactions on decays of muons and ground state mesons in existing experiments. We consider a secluded dark sector exclusively interacting with leptons via either a (leptophilic) scalar or vector mediator. These interactions will therefore influence leptonic decays and deform the energy spectra. We first study the Michel decay of muons, $\mu^+\rightarrow e^+\nu_e \bar{\nu}_\mu$, which allow us to constrain the parameter space reasonably well. Secondly, the rare $\pi^\pm$, $K^\pm$, $D^\pm$ and $D_s^\pm$ decays to $e\nu$ will be considered. Scalar mediators would remove the Standard Model helicity suppression, so that strong constraints can be derived. The resulting bounds on the couplings of the light mediators to electrons and muons still turn out to be somewhat weaker than those from searches at low--energy $e^+e^-$ colliders and the magnetic moment of the muon, respectively. Finally, we show that kaon and pion decays basically exclude a ''Co--SIMP'' scenario where a scalar dark matter particle has a dimension--5 coupling to electrons. |
hep-ph/0410172 | Sorina Lazanu | S. Lazanu, I. Lazanu | Some possible explanations of the discrepancies in the results of
modelling the leakage current of detectors after hadron irradiation | null | null | null | null | hep-ph cond-mat.mtrl-sci physics.ins-det | null | In this contribution we argue that the main discrepancies between model
calculations and experimental data for leakage current after hadron irradiation
could be explained considering the contributions of primary defects in silicon:
vacancy, interstitial and Si_FFCD defect. The source of discrepancies between
data and previous modelling was tentatively attributed to the Si_FFCD defect.
Vacancies and interstitials have a major contribution to the current short time
after irradiation. If these hypotheses are correct, thus, in conditions of
continuous long time irradiation, as e.g. LHC and its upgrades in energy and
luminosity, S-LHC and V-LHC respectively, these contributions will represent a
major problem.
| [
{
"created": "Tue, 12 Oct 2004 17:42:59 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Lazanu",
"S.",
""
],
[
"Lazanu",
"I.",
""
]
] | In this contribution we argue that the main discrepancies between model calculations and experimental data for leakage current after hadron irradiation could be explained considering the contributions of primary defects in silicon: vacancy, interstitial and Si_FFCD defect. The source of discrepancies between data and previous modelling was tentatively attributed to the Si_FFCD defect. Vacancies and interstitials have a major contribution to the current short time after irradiation. If these hypotheses are correct, thus, in conditions of continuous long time irradiation, as e.g. LHC and its upgrades in energy and luminosity, S-LHC and V-LHC respectively, these contributions will represent a major problem. |
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