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|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
hep-ph/9409306 | Matthias Neubert | Matthias Neubert | Theoretical Uncertainties in the Extraction of $|V_{cb}|$ from $\bar
B\to D^*\ell\,\bar\nu$ Decays near Zero Recoil | invited talk presented at the 27th International Conference on High
Energy Physics, Glasgow, Scotland, July 1994, 9 pages LaTeX, 1 figure
appended after \end{document}, CERN-TH.7396/94 | null | null | null | hep-ph | null | I discuss the theoretical uncertainties in the extraction of $|\,V_{cb}|$
from a measurement of the $\bar B\to D^*\ell\,\bar\nu$ decay rate close to zero
recoil. In particular, I combine previous estimates of the $1/m_Q^2$
corrections to the normalization of the hadronic form factor at zero recoil
with sum rules derived by Shifman {\it et al}.\ to obtain a new prediction with
less uncertainty. I also give a prediction for the slope of the form factor
$\widehat\xi(w)$ at zero recoil: $\widehat\varrho^2=0.7\pm 0.2$. Using the most
recent experimental results, I obtain the model-independent value
$|\,V_{cb}|=0.0395\pm 0.0030$.
| [
{
"created": "Wed, 14 Sep 1994 12:09:35 GMT",
"version": "v1"
},
{
"created": "Fri, 16 Sep 1994 15:50:46 GMT",
"version": "v2"
}
] | 2008-02-03 | [
[
"Neubert",
"Matthias",
""
]
] | I discuss the theoretical uncertainties in the extraction of $|\,V_{cb}|$ from a measurement of the $\bar B\to D^*\ell\,\bar\nu$ decay rate close to zero recoil. In particular, I combine previous estimates of the $1/m_Q^2$ corrections to the normalization of the hadronic form factor at zero recoil with sum rules derived by Shifman {\it et al}.\ to obtain a new prediction with less uncertainty. I also give a prediction for the slope of the form factor $\widehat\xi(w)$ at zero recoil: $\widehat\varrho^2=0.7\pm 0.2$. Using the most recent experimental results, I obtain the model-independent value $|\,V_{cb}|=0.0395\pm 0.0030$. |
1905.12953 | Veronica Sanz | M. B. Gavela, J. M. No, V. Sanz and J. F. de Troc\'oniz | Non-Resonant Searches for Axion-Like Particles at the LHC | 10 pages, 7 figures. New version includes interference effects in
dijets | Phys. Rev. Lett. 124, 051802 (2020) | 10.1103/PhysRevLett.124.051802 | null | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We propose a new collider probe for axion-like particles (ALPs), and more
generally for pseudo-Goldstone bosons: non-resonant searches which take
advantage of the derivative nature of their interactions with Standard Model
particles. ALPs can participate as off-shell mediators in the $s$-channel of $2
\to 2$ scattering processes at colliders like the LHC. We exemplify the power
of this novel type of search by deriving new limits on ALP couplings to gauge
bosons via the processes $p p \to Z Z$, $p p \to \gamma \gamma$ and $p p \to j
j$ using Run 2 CMS public data, probing previously unexplored areas of the ALP
parameter space. In addition, we propose future non-resonant searches involving
the ALP coupling to other electroweak bosons and/or the Higgs particle.
| [
{
"created": "Thu, 30 May 2019 10:42:23 GMT",
"version": "v1"
},
{
"created": "Tue, 10 Sep 2019 16:03:44 GMT",
"version": "v2"
}
] | 2020-02-12 | [
[
"Gavela",
"M. B.",
""
],
[
"No",
"J. M.",
""
],
[
"Sanz",
"V.",
""
],
[
"de Trocóniz",
"J. F.",
""
]
] | We propose a new collider probe for axion-like particles (ALPs), and more generally for pseudo-Goldstone bosons: non-resonant searches which take advantage of the derivative nature of their interactions with Standard Model particles. ALPs can participate as off-shell mediators in the $s$-channel of $2 \to 2$ scattering processes at colliders like the LHC. We exemplify the power of this novel type of search by deriving new limits on ALP couplings to gauge bosons via the processes $p p \to Z Z$, $p p \to \gamma \gamma$ and $p p \to j j$ using Run 2 CMS public data, probing previously unexplored areas of the ALP parameter space. In addition, we propose future non-resonant searches involving the ALP coupling to other electroweak bosons and/or the Higgs particle. |
2012.03563 | Piotr Lebiedowicz | Piotr Lebiedowicz, Josef Leutgeb, Otto Nachtmann, Anton Rebhan, Antoni
Szczurek | Central exclusive production of axial-vector $f_{1}$ mesons in
proton-proton collisions | 6 pages, 5 figures, Proceedings of The 40th International Conference
on High Energy physics - ICHEP2020, July 28 - August 6, 2020, Prague, Czech
Republic (virtual meeting) | null | null | null | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The production of $f_{1}$ ($J^{PC} = 1^{++}$) mesons in proton-proton
collisions via pomeron-pomeron fusion is discussed. Two ways to construct the
pomeron-pomeron-$f_{1}$ coupling are presented. Comparisons with data from the
WA102 experiment are made and predictions for RHIC and LHC experiments are
given.
| [
{
"created": "Mon, 7 Dec 2020 10:10:06 GMT",
"version": "v1"
}
] | 2020-12-08 | [
[
"Lebiedowicz",
"Piotr",
""
],
[
"Leutgeb",
"Josef",
""
],
[
"Nachtmann",
"Otto",
""
],
[
"Rebhan",
"Anton",
""
],
[
"Szczurek",
"Antoni",
""
]
] | The production of $f_{1}$ ($J^{PC} = 1^{++}$) mesons in proton-proton collisions via pomeron-pomeron fusion is discussed. Two ways to construct the pomeron-pomeron-$f_{1}$ coupling are presented. Comparisons with data from the WA102 experiment are made and predictions for RHIC and LHC experiments are given. |
hep-ph/0009066 | Martin Hirsch | M. Hirsch and J.W.F. Valle | Reconciling neutrino anomalies in a simple four-neutrino scheme with
R-parity violation | 15 pages, requires axodraw.sty and elsart.cls | Phys.Lett.B495:121-130,2000 | 10.1016/S0370-2693(00)01229-6 | IFIC/00-048 | hep-ph | null | We propose a simple extension of the MSSM based on extra compact dimensions
which includes an $SU(2) \otimes U(1)$ singlet superfield. The fermion present
in this superfield is the sterile neutrino, which combines with one linear
combination of $\nu_e-\nu_{\mu}-\nu_{\tau}$ to form a Dirac pair whose mass
accounts for the LSND anomaly. Its small mass can be ascribed to a volume
suppression factor associated with extra compact dimensions. On the other hand
the sterile neutrino scalar partner can trigger the spontaneous violation of
R-parity, thereby inducing the necessary mass splittings to fit also the solar
and atmospheric neutrino data. Thus the model can explain all neutrino
oscillation data. It leads to four predictions for the neutrino oscillation
parameters and implies that the atmospheric neutrino problem must include at
least some $\nu_{\mu} \to \nu_s$ oscillations, which will be testable in the
near future. Moreover it also predicts that the lightest supersymmetric
particle (LSP) decays visibly via lepton number violating modes, which could be
searched for at present and future accelerators.
| [
{
"created": "Wed, 6 Sep 2000 14:56:59 GMT",
"version": "v1"
}
] | 2009-09-17 | [
[
"Hirsch",
"M.",
""
],
[
"Valle",
"J. W. F.",
""
]
] | We propose a simple extension of the MSSM based on extra compact dimensions which includes an $SU(2) \otimes U(1)$ singlet superfield. The fermion present in this superfield is the sterile neutrino, which combines with one linear combination of $\nu_e-\nu_{\mu}-\nu_{\tau}$ to form a Dirac pair whose mass accounts for the LSND anomaly. Its small mass can be ascribed to a volume suppression factor associated with extra compact dimensions. On the other hand the sterile neutrino scalar partner can trigger the spontaneous violation of R-parity, thereby inducing the necessary mass splittings to fit also the solar and atmospheric neutrino data. Thus the model can explain all neutrino oscillation data. It leads to four predictions for the neutrino oscillation parameters and implies that the atmospheric neutrino problem must include at least some $\nu_{\mu} \to \nu_s$ oscillations, which will be testable in the near future. Moreover it also predicts that the lightest supersymmetric particle (LSP) decays visibly via lepton number violating modes, which could be searched for at present and future accelerators. |
hep-ph/9911480 | Oh Yongseok | Nikolai I. Kochelev, Dong-Pil Min, Yongseok Oh, Vicente Vento, Andrey
V. Vinnikov | New anomalous trajectory in Regge theory | 20 pages, REVTeX, 8 figures (9 eps files), version to appear in Phys.
Rev. D | Phys.Rev. D61 (2000) 094008 | 10.1103/PhysRevD.61.094008 | SNUTP-99-049 | hep-ph hep-ex nucl-th | null | We show that a new Regge trajectory with \alpha_{f_1} (0) \approx 1 and slope
\alpha_{f_1}'(0) \approx 0 explains the features of hadron-hadron scattering
and photoproduction of the rho and phi mesons at large energy and momentum
transfer. This trajectory with quantum numbers P = C = +1 and odd signature can
be considered as a natural partner of the Pomeron which has even signature. The
odd signature of the new exchange leads to contributions to the spin-dependent
cross sections, which do not vanish at large energy. The links between the
anomalous properties of this trajectory, the axial anomaly and the flavor
singlet axial vector f_1 (1285) meson are discussed.
| [
{
"created": "Thu, 25 Nov 1999 06:44:16 GMT",
"version": "v1"
},
{
"created": "Mon, 17 Jan 2000 10:27:55 GMT",
"version": "v2"
}
] | 2009-10-31 | [
[
"Kochelev",
"Nikolai I.",
""
],
[
"Min",
"Dong-Pil",
""
],
[
"Oh",
"Yongseok",
""
],
[
"Vento",
"Vicente",
""
],
[
"Vinnikov",
"Andrey V.",
""
]
] | We show that a new Regge trajectory with \alpha_{f_1} (0) \approx 1 and slope \alpha_{f_1}'(0) \approx 0 explains the features of hadron-hadron scattering and photoproduction of the rho and phi mesons at large energy and momentum transfer. This trajectory with quantum numbers P = C = +1 and odd signature can be considered as a natural partner of the Pomeron which has even signature. The odd signature of the new exchange leads to contributions to the spin-dependent cross sections, which do not vanish at large energy. The links between the anomalous properties of this trajectory, the axial anomaly and the flavor singlet axial vector f_1 (1285) meson are discussed. |
0808.2298 | Ayres Freitas | M. Carena, A. Freitas, C.E.M. Wagner | Light Stop Searches at the LHC in Events with One Hard Photon or Jet and
Missing Energy | 17 pages, 6 figures | JHEP 0810:109,2008 | 10.1088/1126-6708/2008/10/109 | ANL-HEP-PR-08-46, EFI-08-22, FERMILAB-PUB-08-269-T | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Low energy supersymmetric models provide a solution to the hierarchy problem
and also have the necessary ingredients to solve two of the most outstanding
issues in cosmology: the origin of the baryon asymmetry and the source of dark
matter. In the MSSM, weak scale generation of the baryon asymmetry may be
achieved in the presence of light stops, with masses lower than about 130 GeV.
Moreover, the proper dark matter density may be obtained in the stop-neutralino
co-annihilation region, where the stop-neutralino mass difference is smaller
than a few tens of GeV. Searches for scalar top quarks (stops) in pair
production processes at the Tevatron and at the Large Hadron Collider (LHC)
become very challenging in this region of parameters. At the LHC, however,
light stops proceeding from the decay of gluino pairs may be identified,
provided the gluino mass is smaller than about 900 GeV. In this article we
propose an alternative method for stop searches in the co-annihilation region,
based on the search for these particles in events with missing energy plus one
hard photon or jet. We show that this method is quite efficient and, when
complemented with ongoing Tevatron searches, allows to probe stop masses up to
about 160 GeV, fully probing the region of parameters consistent with
electroweak baryogenesis in the MSSM.
| [
{
"created": "Sun, 17 Aug 2008 16:40:04 GMT",
"version": "v1"
}
] | 2009-05-08 | [
[
"Carena",
"M.",
""
],
[
"Freitas",
"A.",
""
],
[
"Wagner",
"C. E. M.",
""
]
] | Low energy supersymmetric models provide a solution to the hierarchy problem and also have the necessary ingredients to solve two of the most outstanding issues in cosmology: the origin of the baryon asymmetry and the source of dark matter. In the MSSM, weak scale generation of the baryon asymmetry may be achieved in the presence of light stops, with masses lower than about 130 GeV. Moreover, the proper dark matter density may be obtained in the stop-neutralino co-annihilation region, where the stop-neutralino mass difference is smaller than a few tens of GeV. Searches for scalar top quarks (stops) in pair production processes at the Tevatron and at the Large Hadron Collider (LHC) become very challenging in this region of parameters. At the LHC, however, light stops proceeding from the decay of gluino pairs may be identified, provided the gluino mass is smaller than about 900 GeV. In this article we propose an alternative method for stop searches in the co-annihilation region, based on the search for these particles in events with missing energy plus one hard photon or jet. We show that this method is quite efficient and, when complemented with ongoing Tevatron searches, allows to probe stop masses up to about 160 GeV, fully probing the region of parameters consistent with electroweak baryogenesis in the MSSM. |
1509.08214 | D.N. Triantafyllopoulos | E. Iancu, J.D. Madrigal, A.H. Mueller, G. Soyez, D.N.
Triantafyllopoulos | Resumming large higher-order corrections in non-linear QCD evolution | 4 pages, 4 figures, based on talk given at Hard Probes 2015, 29 June
- 3 July 2015, Montreal, Canada | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Linear and non-linear QCD evolutions at high energy suffer from severe issues
related to convergence, due to higher order corrections enhanced by large
double and single transverse logarithms. We resum double logarithms to all
orders by taking into account successive soft gluon emissions strongly ordered
in lifetime. We further resum single logarithms generated by the first
non-singular part of the splitting functions and by the one-loop running of the
coupling. The resulting collinearly improved BK equation admits stable
solutions, which are used to successfully fit the HERA data at small-x for
physically acceptable initial conditions and reasonable values of the fit
parameters.
| [
{
"created": "Mon, 28 Sep 2015 06:51:21 GMT",
"version": "v1"
}
] | 2015-09-29 | [
[
"Iancu",
"E.",
""
],
[
"Madrigal",
"J. D.",
""
],
[
"Mueller",
"A. H.",
""
],
[
"Soyez",
"G.",
""
],
[
"Triantafyllopoulos",
"D. N.",
""
]
] | Linear and non-linear QCD evolutions at high energy suffer from severe issues related to convergence, due to higher order corrections enhanced by large double and single transverse logarithms. We resum double logarithms to all orders by taking into account successive soft gluon emissions strongly ordered in lifetime. We further resum single logarithms generated by the first non-singular part of the splitting functions and by the one-loop running of the coupling. The resulting collinearly improved BK equation admits stable solutions, which are used to successfully fit the HERA data at small-x for physically acceptable initial conditions and reasonable values of the fit parameters. |
1811.06619 | Jordan Smolinsky | Arvind Rajaraman, Jordan Smolinsky | Self-Interacting Dark Matter With a Neutrinophilic Scalar Mediator | 9 pages, 4 figures; v3: published version | null | null | UCI-TR-2018-16 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We examine the phenomenology of a simplified model of fermionic dark matter
coupled to a light scalar mediator carrying lepton number 2. We find that the
mediator can be very light and still consistent with laboratory and
cosmological bounds. This model satisfies the thermal relic condition for
natural values of dimensionless coupling constants and admits a mediator in the
$10 - 100 ~\text{MeV}$ mass range favored by small scale structure
observations. As such, this model provides an excellent candidate for
self-interacting dark matter.
| [
{
"created": "Thu, 15 Nov 2018 23:01:52 GMT",
"version": "v1"
},
{
"created": "Tue, 18 Dec 2018 01:42:02 GMT",
"version": "v2"
},
{
"created": "Thu, 25 Jun 2020 21:05:11 GMT",
"version": "v3"
}
] | 2020-06-29 | [
[
"Rajaraman",
"Arvind",
""
],
[
"Smolinsky",
"Jordan",
""
]
] | We examine the phenomenology of a simplified model of fermionic dark matter coupled to a light scalar mediator carrying lepton number 2. We find that the mediator can be very light and still consistent with laboratory and cosmological bounds. This model satisfies the thermal relic condition for natural values of dimensionless coupling constants and admits a mediator in the $10 - 100 ~\text{MeV}$ mass range favored by small scale structure observations. As such, this model provides an excellent candidate for self-interacting dark matter. |
1012.4480 | Frank Tackmann | Carola F. Berger, Claudio Marcantonini, Iain W. Stewart, Frank
J.Tackmann and Wouter J. Waalewijn | Higgs Production with a Central Jet Veto at NNLL+NNLO | 38 pages + appendices, 21 figures, v2: extended discussion section,
added figure with individual scale variations, journal version | null | 10.1007/JHEP04(2011)092 | MIT-CTP 4122 | hep-ph hep-ex nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | A major ingredient in Higgs searches at the Tevatron and LHC is the
elimination of backgrounds with jets. In current H -> WW -> lnulnu searches,
jet algorithms are used to veto central jets to obtain a 0-jet sample, which is
then analyzed to discover the Higgs signal. Imposing this tight jet veto
induces large double logarithms which significantly modify the Higgs production
cross section. These jet-veto logarithms are presently only accounted for at
fixed order or with the leading-logarithmic summation from parton-shower Monte
Carlos. Here we consider Higgs production with an inclusive event-shape
variable for the jet veto, namely beam thrust Tau_cm, which has a close
correspondence with a traditional p_T jet veto. Tau_cm allows us to
systematically sum the large jet-veto logarithms to higher orders and to
provide better estimates for theoretical uncertainties. We present results for
the 0-jet Higgs production cross section from gluon fusion at
next-to-next-to-leading-logarithmic order (NNLL), fully incorporating
fixed-order results at next-to-next-to-leading order (NNLO). At this order the
scale uncertainty is 15-20%, depending on the cut, implying that a larger scale
uncertainty should be used in current Tevatron bounds on the Higgs.
| [
{
"created": "Mon, 20 Dec 2010 21:21:44 GMT",
"version": "v1"
},
{
"created": "Sat, 9 Apr 2011 00:14:36 GMT",
"version": "v2"
}
] | 2015-05-20 | [
[
"Berger",
"Carola F.",
""
],
[
"Marcantonini",
"Claudio",
""
],
[
"Stewart",
"Iain W.",
""
],
[
"Tackmann",
"Frank J.",
""
],
[
"Waalewijn",
"Wouter J.",
""
]
] | A major ingredient in Higgs searches at the Tevatron and LHC is the elimination of backgrounds with jets. In current H -> WW -> lnulnu searches, jet algorithms are used to veto central jets to obtain a 0-jet sample, which is then analyzed to discover the Higgs signal. Imposing this tight jet veto induces large double logarithms which significantly modify the Higgs production cross section. These jet-veto logarithms are presently only accounted for at fixed order or with the leading-logarithmic summation from parton-shower Monte Carlos. Here we consider Higgs production with an inclusive event-shape variable for the jet veto, namely beam thrust Tau_cm, which has a close correspondence with a traditional p_T jet veto. Tau_cm allows us to systematically sum the large jet-veto logarithms to higher orders and to provide better estimates for theoretical uncertainties. We present results for the 0-jet Higgs production cross section from gluon fusion at next-to-next-to-leading-logarithmic order (NNLL), fully incorporating fixed-order results at next-to-next-to-leading order (NNLO). At this order the scale uncertainty is 15-20%, depending on the cut, implying that a larger scale uncertainty should be used in current Tevatron bounds on the Higgs. |
hep-ph/9902439 | Linux User Rhs | O. Bertolami and F.M. Nunes | Nucleosynthesis Constraints on a Scale-Dependent New Intermediate Range
Interaction | 14 pages, Latex plus 2 eps figures. To be published in Physics
Letters B | Phys.Lett. B452 (1999) 108-114 | 10.1016/S0370-2693(99)00253-1 | DF/IST-4.98 | hep-ph astro-ph gr-qc | null | We derive constraints on the strength of a new intermediate range interaction
that couples to baryon number from primordial nucleosynthesis yields. The
nucleosysnthesis limits here used arise from matching observations and
predictions of standard and inhomogeneous primordial scenarios. We show that
the standard nucleosynthesis scenario is more restrictive ($\alpha_5 \lsim
0.2$) when the range of the interaction is greater than about 1 m. We further
discuss the implications of considering the scalar particle responsible for the
new interaction as the main component of the dark matter in the galactic halo
such that its decay can account for the ionization of hydrogen in the
interstellar medium and the temperature of Lyman-$\alpha$ clouds.
| [
{
"created": "Tue, 23 Feb 1999 11:20:31 GMT",
"version": "v1"
}
] | 2009-10-31 | [
[
"Bertolami",
"O.",
""
],
[
"Nunes",
"F. M.",
""
]
] | We derive constraints on the strength of a new intermediate range interaction that couples to baryon number from primordial nucleosynthesis yields. The nucleosysnthesis limits here used arise from matching observations and predictions of standard and inhomogeneous primordial scenarios. We show that the standard nucleosynthesis scenario is more restrictive ($\alpha_5 \lsim 0.2$) when the range of the interaction is greater than about 1 m. We further discuss the implications of considering the scalar particle responsible for the new interaction as the main component of the dark matter in the galactic halo such that its decay can account for the ionization of hydrogen in the interstellar medium and the temperature of Lyman-$\alpha$ clouds. |
1309.3093 | A. V. Luchinsky | V.V. Braguta, A.K. Likhoded, A.V. Luchinsky, S.V. Poslavsky | Analytical calculation of heavy quarkonia production processes in
computer | minor changes | null | 10.1088/1742-6596/523/1/012038 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | This report is devoted to the analytical calculation of heavy quarkonia
production processes in modern experiments such as LHC, B-factories and
superB-factories in computer. Theoretical description of heavy quarkonia is
based on the factorization theorem. This theorem leads to special structure of
the production amplitudes which can be used to develop computer algorithm which
calculates these amplitudes automatically. This report is devoted to the
description of this algorithm. As an example of its application we present the
results of the calculation of double charmonia production in bottomonia decays
and inclusive the $\chi_{cJ}$ mesons production in pp-collisions.
| [
{
"created": "Thu, 12 Sep 2013 10:14:33 GMT",
"version": "v1"
},
{
"created": "Fri, 13 Sep 2013 07:57:06 GMT",
"version": "v2"
},
{
"created": "Mon, 7 Oct 2013 06:06:50 GMT",
"version": "v3"
}
] | 2015-06-17 | [
[
"Braguta",
"V. V.",
""
],
[
"Likhoded",
"A. K.",
""
],
[
"Luchinsky",
"A. V.",
""
],
[
"Poslavsky",
"S. V.",
""
]
] | This report is devoted to the analytical calculation of heavy quarkonia production processes in modern experiments such as LHC, B-factories and superB-factories in computer. Theoretical description of heavy quarkonia is based on the factorization theorem. This theorem leads to special structure of the production amplitudes which can be used to develop computer algorithm which calculates these amplitudes automatically. This report is devoted to the description of this algorithm. As an example of its application we present the results of the calculation of double charmonia production in bottomonia decays and inclusive the $\chi_{cJ}$ mesons production in pp-collisions. |
hep-ph/9805350 | Massimiliano Grazzini | M. Grazzini | Fracture functions: factorization and evolution | latex, 4 pages including 2 postscript figures; Talk given at the
DIS98 Workshop, Brussels, 4-8, 1998 | null | null | null | hep-ph | null | Fracture functions and their evolution equations are reviewed. Some
phenomenological applications are briefly discussed.
| [
{
"created": "Mon, 18 May 1998 09:35:44 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Grazzini",
"M.",
""
]
] | Fracture functions and their evolution equations are reviewed. Some phenomenological applications are briefly discussed. |
2109.11815 | Lara Mason | Alan S. Cornell, Wesley Doorsamy, Benjamin Fuks, Gerhard Harmsen, Lara
Mason | Boosted decision trees in the era of new physics: a smuon analysis case
study | 35 pages, 7 images | JHEP 04 (2022) 015 | 10.1007/JHEP04(2022)015 | null | hep-ph hep-ex physics.comp-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Machine learning algorithms are growing increasingly popular in particle
physics analyses, where they are used for their ability to solve difficult
classification and regression problems. While the tools are very powerful, they
may often be under- or mis-utilised. In the following, we investigate the use
of gradient boosting techniques as applicable to a generic particle physics
problem. We use as an example a Beyond the Standard Model smuon collider
analysis which applies to both current and future hadron colliders, and we
compare our results to a traditional cut-and-count approach. In particular, we
interrogate the use of metrics in imbalanced datasets which are characteristic
of high energy physics problems, offering an alternative to the widely used
area under the curve (auc) metric through a novel use of the F-score metric. We
present an in-depth comparison of feature selection and investigation using a
principal component analysis, Shapley values, and feature permutation methods
in a way which we hope will be widely applicable to future particle physics
analyses. Moreover, we show that a machine learning model can extend the 95%
confidence level exclusions obtained in a traditional cut-and-count analysis,
while potentially bypassing the need for complicated feature selections.
Finally, we discuss the possibility of constructing a general machine learning
model which is applicable to probe a two-dimensional mass plane.
| [
{
"created": "Fri, 24 Sep 2021 08:58:16 GMT",
"version": "v1"
},
{
"created": "Wed, 25 May 2022 08:52:00 GMT",
"version": "v2"
}
] | 2022-05-26 | [
[
"Cornell",
"Alan S.",
""
],
[
"Doorsamy",
"Wesley",
""
],
[
"Fuks",
"Benjamin",
""
],
[
"Harmsen",
"Gerhard",
""
],
[
"Mason",
"Lara",
""
]
] | Machine learning algorithms are growing increasingly popular in particle physics analyses, where they are used for their ability to solve difficult classification and regression problems. While the tools are very powerful, they may often be under- or mis-utilised. In the following, we investigate the use of gradient boosting techniques as applicable to a generic particle physics problem. We use as an example a Beyond the Standard Model smuon collider analysis which applies to both current and future hadron colliders, and we compare our results to a traditional cut-and-count approach. In particular, we interrogate the use of metrics in imbalanced datasets which are characteristic of high energy physics problems, offering an alternative to the widely used area under the curve (auc) metric through a novel use of the F-score metric. We present an in-depth comparison of feature selection and investigation using a principal component analysis, Shapley values, and feature permutation methods in a way which we hope will be widely applicable to future particle physics analyses. Moreover, we show that a machine learning model can extend the 95% confidence level exclusions obtained in a traditional cut-and-count analysis, while potentially bypassing the need for complicated feature selections. Finally, we discuss the possibility of constructing a general machine learning model which is applicable to probe a two-dimensional mass plane. |
2401.05989 | Ping Chen | Ping Chen, Zhan-Wei Liu, Zi-Le Zhang, Si-Qiang Luo, Fu-Lai Wang,
Jun-Zhang Wang, Xiang Liu | The role of electromagnetic interaction in the $X(3872)$ and its analogs | 17 pages, 8 figures, 7 tables | Phys.Rev.D 109, 094002 (2024) | 10.1103/PhysRevD.109.094002 | null | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We investigate the role of the electromagnetic interaction in the formation
and decay of the $X(3872)$. The binding properties of the $X(3872)$ are studied
by assuming the molecular nature and considering the $S$-$D$ wave mixing,
isospin breaking, and coupled channel effects, and in particular the correction
from the electromagnetic interaction. The radiative decays can better reflect
the difference between the charged and neutral $D\bar D^*$ components, since
the electromagnetic interaction explicitly breaks the isospin symmetry. We
further study the radiative decay widths with the obtained wave functions for
different $D\bar D^*$ channels. We also explore other similar hidden-charm
molecular states. The electromagnetic interaction can make the molecule
tighter. Our result of the radiative decay width for $X(3872)\rightarrow \gamma
J/\psi$ is in agreement with the experiment. The branching ratio
$R_{\gamma\psi}$ is less than 1 in our framework, which supports the Belle and
BESIII measurements.
| [
{
"created": "Thu, 11 Jan 2024 15:45:15 GMT",
"version": "v1"
},
{
"created": "Wed, 20 Mar 2024 01:48:02 GMT",
"version": "v2"
},
{
"created": "Thu, 2 May 2024 03:38:53 GMT",
"version": "v3"
}
] | 2024-05-03 | [
[
"Chen",
"Ping",
""
],
[
"Liu",
"Zhan-Wei",
""
],
[
"Zhang",
"Zi-Le",
""
],
[
"Luo",
"Si-Qiang",
""
],
[
"Wang",
"Fu-Lai",
""
],
[
"Wang",
"Jun-Zhang",
""
],
[
"Liu",
"Xiang",
""
]
] | We investigate the role of the electromagnetic interaction in the formation and decay of the $X(3872)$. The binding properties of the $X(3872)$ are studied by assuming the molecular nature and considering the $S$-$D$ wave mixing, isospin breaking, and coupled channel effects, and in particular the correction from the electromagnetic interaction. The radiative decays can better reflect the difference between the charged and neutral $D\bar D^*$ components, since the electromagnetic interaction explicitly breaks the isospin symmetry. We further study the radiative decay widths with the obtained wave functions for different $D\bar D^*$ channels. We also explore other similar hidden-charm molecular states. The electromagnetic interaction can make the molecule tighter. Our result of the radiative decay width for $X(3872)\rightarrow \gamma J/\psi$ is in agreement with the experiment. The branching ratio $R_{\gamma\psi}$ is less than 1 in our framework, which supports the Belle and BESIII measurements. |
2211.11780 | Francesco Giovanni Celiberto | Francesco Giovanni Celiberto | Stabilizing BFKL via heavy-flavor and NRQCD fragmentation | 6 pages, 1 figure. Presented at Diffraction and Low-x 2022, 24-30
September 2022 | null | null | null | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We bring evidence that the recently discovered property of natural stability
of the high-energy resummation is directly connected to the fragmentation
mechanism of heavy hadrons. As a phenomenological support, we provide
predictions for differential distributions sensitive to heavy-hadron tags,
calculated at the next-to-leading logarithmic level of the hybrid
high-energy/collinear factorization (NLL/NLO), as implemented in the JETHAD
multimodular code. We show that the stabilizing mechanism is encoded in gluon
channels of both heavy-flavor collinear fragmentation functions extracted from
data and the ones evolved from a non-relativistic QCD input.
| [
{
"created": "Mon, 21 Nov 2022 19:00:02 GMT",
"version": "v1"
}
] | 2022-11-23 | [
[
"Celiberto",
"Francesco Giovanni",
""
]
] | We bring evidence that the recently discovered property of natural stability of the high-energy resummation is directly connected to the fragmentation mechanism of heavy hadrons. As a phenomenological support, we provide predictions for differential distributions sensitive to heavy-hadron tags, calculated at the next-to-leading logarithmic level of the hybrid high-energy/collinear factorization (NLL/NLO), as implemented in the JETHAD multimodular code. We show that the stabilizing mechanism is encoded in gluon channels of both heavy-flavor collinear fragmentation functions extracted from data and the ones evolved from a non-relativistic QCD input. |
hep-ph/9302268 | Felix Schlumpf | Felix Schlumpf | The Electric and Magnetic Form Factors of the Neutron | 6 pages, LaTeX, SLAC-PUB-6050 | Mod.Phys.Lett. A8 (1993) 2135-2140 | 10.1142/S0217732393001859 | null | hep-ph | null | We derive the electric and magnetic form factors of the neutron in the
framework of a relativistic constituent quark model. Our parameter free
prediction agrees well with a recent, accurate measurement. The relativistic
features of the model and the specific form of the wave function are essential
for the result. Comparisons are made to other models based on VMD, PQCD and QCD
sum rules.
| [
{
"created": "Wed, 17 Feb 1993 18:15:47 GMT",
"version": "v1"
}
] | 2015-06-25 | [
[
"Schlumpf",
"Felix",
""
]
] | We derive the electric and magnetic form factors of the neutron in the framework of a relativistic constituent quark model. Our parameter free prediction agrees well with a recent, accurate measurement. The relativistic features of the model and the specific form of the wave function are essential for the result. Comparisons are made to other models based on VMD, PQCD and QCD sum rules. |
hep-ph/0305146 | Olga Mena Requejo | O. Mena | Puzzling out Neutrino Mixing Through Golden and Silver Measurements | 6 pages, 8 figures. Presented at XXXVIII Rencontre De Moriond:
Electroweak Interactions and Unified Theories Les Arcs, France, March 15--22,
2003 | null | null | null | hep-ph | null | We update a recent work devoted to resolve the degeneracies that appear in
the simultaneous extraction of $\theta_{13}$ and $\delta$ at future Neutrino
Factories (NF, that exploit the \emph{golden} channels, i.e. $\nu_e\to\nu_\mu$
($\bar{\nu}_e\to\bar{\nu}_\mu$)) and Superbeam experiments (SB, that measure
the $\nu_\mu\to\nu_e$ ($\bar{\nu}_\mu\to\bar{\nu}_e$) transitions). We consider
the neutrino fluxes obtained with a new optics design for the CERN-SPL SB and
assume the solar parameters within the LMA-I and the LMA-II regions indicated
by recent KamLAND data. The dangerous fake solution associated with the
$\theta_{23}$-ambiguity remains after the combination of data from these two
facilities: in this perspective, we analyze the impact of the NF-\emph{silver}
channels, i.e. $\nu_e\to\nu_\tau$ ($\bar{\nu}_e\to\bar{\nu}_\tau$). The
combination of data from these three experiments -NF(\emph{golden} and
\emph{silver} channels) plus SPL SB- can discover leptonic CP violation for
values of $\theta_{13}\ge 1^{\circ}$.
| [
{
"created": "Wed, 14 May 2003 08:38:58 GMT",
"version": "v1"
},
{
"created": "Mon, 19 May 2003 13:32:41 GMT",
"version": "v2"
}
] | 2007-05-23 | [
[
"Mena",
"O.",
""
]
] | We update a recent work devoted to resolve the degeneracies that appear in the simultaneous extraction of $\theta_{13}$ and $\delta$ at future Neutrino Factories (NF, that exploit the \emph{golden} channels, i.e. $\nu_e\to\nu_\mu$ ($\bar{\nu}_e\to\bar{\nu}_\mu$)) and Superbeam experiments (SB, that measure the $\nu_\mu\to\nu_e$ ($\bar{\nu}_\mu\to\bar{\nu}_e$) transitions). We consider the neutrino fluxes obtained with a new optics design for the CERN-SPL SB and assume the solar parameters within the LMA-I and the LMA-II regions indicated by recent KamLAND data. The dangerous fake solution associated with the $\theta_{23}$-ambiguity remains after the combination of data from these two facilities: in this perspective, we analyze the impact of the NF-\emph{silver} channels, i.e. $\nu_e\to\nu_\tau$ ($\bar{\nu}_e\to\bar{\nu}_\tau$). The combination of data from these three experiments -NF(\emph{golden} and \emph{silver} channels) plus SPL SB- can discover leptonic CP violation for values of $\theta_{13}\ge 1^{\circ}$. |
hep-ph/9906526 | Kimball A. Milton | Leonard Gamberg, George R. Kalbfleisch, and Kimball A. Milton | Direct and Indirect Searches for Low-Mass Magnetic Monopoles | 20 pages, 1 ps figure, contributed to Kurt Haller's festschrift | Found.Phys. 30 (2000) 543-565 | 10.1023/A:1003668812097 | OKHEP-99-04 | hep-ph | null | Recently, there has been renewed interest in the search for low-mass magnetic
monopoles. At the University of Oklahoma we are performing an experiment
(Fermilab E882) using material from the old D0 and CDF detectors to set limits
on the existence of Dirac monopoles of masses of the order of 500 GeV. To set
such limits, estimates must be made of the production rate of such monopoles at
the Tevatron collider, and of the binding strength of any such produced
monopoles to matter. Here we sketch the still primitive theory of such
interactions, and indicate why we believe a credible limit may still be
obtained. On the other hand, there have been proposals that the classic
Euler-Heisenberg Lagrangian together with duality could be employed to set
limits on magnetic monopoles having masses less than 1 TeV, based on virtual,
rather than real processes. The D0 collaboration at Fermilab has used such a
proposal to set mass limits based on the nonobservation of pairs of photons
each with high transverse momentum. We critique the underlying theory, by
showing that the cross section violates unitarity at the quoted limits and is
unstable with respect to radiative corrections. We therefore believe that no
significant limit can be obtained from the current experiments, based on
virtual monopole processes.
| [
{
"created": "Mon, 28 Jun 1999 20:47:25 GMT",
"version": "v1"
}
] | 2022-10-12 | [
[
"Gamberg",
"Leonard",
""
],
[
"Kalbfleisch",
"George R.",
""
],
[
"Milton",
"Kimball A.",
""
]
] | Recently, there has been renewed interest in the search for low-mass magnetic monopoles. At the University of Oklahoma we are performing an experiment (Fermilab E882) using material from the old D0 and CDF detectors to set limits on the existence of Dirac monopoles of masses of the order of 500 GeV. To set such limits, estimates must be made of the production rate of such monopoles at the Tevatron collider, and of the binding strength of any such produced monopoles to matter. Here we sketch the still primitive theory of such interactions, and indicate why we believe a credible limit may still be obtained. On the other hand, there have been proposals that the classic Euler-Heisenberg Lagrangian together with duality could be employed to set limits on magnetic monopoles having masses less than 1 TeV, based on virtual, rather than real processes. The D0 collaboration at Fermilab has used such a proposal to set mass limits based on the nonobservation of pairs of photons each with high transverse momentum. We critique the underlying theory, by showing that the cross section violates unitarity at the quoted limits and is unstable with respect to radiative corrections. We therefore believe that no significant limit can be obtained from the current experiments, based on virtual monopole processes. |
1006.4293 | Michal Praszalowicz | Larry McLerran and Michal Praszalowicz | Saturation and Scaling of Multiplicity, Mean p_T and p_T Distributions
from 200 GeV < sqrt{s} < 7 TeV | 10 pages, 6 figures. In v2 references added, minor typos corrected | Acta Phys.Polon.B41:1917-1926,2010 | null | null | hep-ph nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The multiplicity, average transverse momentum, and charged particle
transverse momentum distributions have recently been measured in LHC
experiments. The multiplicity and average transverse momentum grow with beam
energy. Such growth is expected in the theory of the Color Glass Condensate, a
theory that incorporates the physics of saturation into the evolution of the
gluon distribution. We show that the energy dependence of the $p\overline{p}$
data and the LHC data for $pp$ scattering at \sqrt{s} > 200 GeV may be simply
described using a minimal amount of model input. Such a description uses
parameters consistent with the Color Glass Condensate descriptions of HERA and
RHIC experimental data.
| [
{
"created": "Tue, 22 Jun 2010 13:46:01 GMT",
"version": "v1"
},
{
"created": "Thu, 8 Jul 2010 10:38:22 GMT",
"version": "v2"
}
] | 2014-11-21 | [
[
"McLerran",
"Larry",
""
],
[
"Praszalowicz",
"Michal",
""
]
] | The multiplicity, average transverse momentum, and charged particle transverse momentum distributions have recently been measured in LHC experiments. The multiplicity and average transverse momentum grow with beam energy. Such growth is expected in the theory of the Color Glass Condensate, a theory that incorporates the physics of saturation into the evolution of the gluon distribution. We show that the energy dependence of the $p\overline{p}$ data and the LHC data for $pp$ scattering at \sqrt{s} > 200 GeV may be simply described using a minimal amount of model input. Such a description uses parameters consistent with the Color Glass Condensate descriptions of HERA and RHIC experimental data. |
0709.2204 | Masahiro Inui | M. Inui, H. Kohyama, A. Ni\'egawa | Ferromagnetism of two-flavor quark matter in chiral and/or
color-superconducting phases at zero and finite temperatures | 25 pages, 10 figures | null | null | null | hep-ph | null | We study the phase structure of the unpolarized and polarized two-flavor
quark matters at zero and finite temperatures within the Nambu--Jona-Lasinio
(NJL) model. We focus on the region, which includes the coexisting phase of
quark-antiquark and diquark condensates. Generalizing the NJL model so as to
describe the polarized quark matter, we compute the thermodynamic potential as
a function of the quark chemical potential ($\mu$), the temperature ($T$), and
the polarization parameter. The result heavily depends on the ratio $G_D /
G_S$, where $G_S$ is the quark-antiquark coupling constant and $G_D$ is the
diquark coupling constant. We find that, for small $G_D / G_S$, the
"ferromagnetic" phase is energetically favored over the "paramagnetic" phase.
On the other hand, for large $G_D / G_S$, there appears the window in the
($\mu, T$)-plane, in which the "paramagnetic" phase is favored.
| [
{
"created": "Fri, 14 Sep 2007 04:03:53 GMT",
"version": "v1"
}
] | 2007-09-17 | [
[
"Inui",
"M.",
""
],
[
"Kohyama",
"H.",
""
],
[
"Niégawa",
"A.",
""
]
] | We study the phase structure of the unpolarized and polarized two-flavor quark matters at zero and finite temperatures within the Nambu--Jona-Lasinio (NJL) model. We focus on the region, which includes the coexisting phase of quark-antiquark and diquark condensates. Generalizing the NJL model so as to describe the polarized quark matter, we compute the thermodynamic potential as a function of the quark chemical potential ($\mu$), the temperature ($T$), and the polarization parameter. The result heavily depends on the ratio $G_D / G_S$, where $G_S$ is the quark-antiquark coupling constant and $G_D$ is the diquark coupling constant. We find that, for small $G_D / G_S$, the "ferromagnetic" phase is energetically favored over the "paramagnetic" phase. On the other hand, for large $G_D / G_S$, there appears the window in the ($\mu, T$)-plane, in which the "paramagnetic" phase is favored. |
hep-ph/0402189 | Amjad Gilani | Fayyazuddin | Final state phases in B -> D\pi, \bar{D}\pi decays and CP-asymmetry | 6 pages, no figure | Phys.Rev. D70 (2004) 114018 | 10.1103/PhysRevD.70.114018 | NCP-QAU/0218-2004 | hep-ph | null | Final state phases \delta_f and \delta_f' in B-> D pi, barD pi decays are
shown to be equal i.e. \delta =\delta_f-\delta_f' = 0. Thus CP-violating
asymmetry A(t) is independent of final state phases. The estimate for the
phases \delta_f and \delta_f' is also given.
| [
{
"created": "Wed, 18 Feb 2004 15:24:35 GMT",
"version": "v1"
},
{
"created": "Thu, 22 Apr 2004 09:24:24 GMT",
"version": "v2"
},
{
"created": "Sat, 11 Sep 2004 16:36:30 GMT",
"version": "v3"
}
] | 2009-11-10 | [
[
"Fayyazuddin",
"",
""
]
] | Final state phases \delta_f and \delta_f' in B-> D pi, barD pi decays are shown to be equal i.e. \delta =\delta_f-\delta_f' = 0. Thus CP-violating asymmetry A(t) is independent of final state phases. The estimate for the phases \delta_f and \delta_f' is also given. |
hep-ph/9404279 | null | V.M.Belyaev | $\pi$-$A_1$ electromagnetic form factors and light-cone QCD sum rules | LATEX, 15 pages, 4 figures (only changes in the references) | Z.Phys.C65:93-100,1995 | 10.1007/BF01571308 | null | hep-ph | null | Electromagnetic form factors of the transition $\pi+\gamma_{virt.}\ra A_1$
are calculated by QCD sum rules technique with the description of the pion in
terms of the set of wave functions of increasing twist. Obtained results are
compared with standard QCD sum rule calculations.
| [
{
"created": "Mon, 18 Apr 1994 15:48:50 GMT",
"version": "v1"
},
{
"created": "Thu, 21 Apr 1994 15:29:53 GMT",
"version": "v2"
}
] | 2014-11-17 | [
[
"Belyaev",
"V. M.",
""
]
] | Electromagnetic form factors of the transition $\pi+\gamma_{virt.}\ra A_1$ are calculated by QCD sum rules technique with the description of the pion in terms of the set of wave functions of increasing twist. Obtained results are compared with standard QCD sum rule calculations. |
1003.1960 | Jens Mueller | Christian S. Fischer, Axel Maas and Jens A. Mueller | Chiral and deconfinement transition from correlation functions: SU(2)
vs. SU(3) | 15 pages, 9 figures. For clarification one paragraph and two
references added in the introduction and two sentences at the end of the
first and last paragraph of the summary. Appeared in EPJC | Eur.Phys.J.C68:165-181,2010 | 10.1140/epjc/s10052-010-1343-1 | null | hep-ph hep-lat nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study a gauge invariant order parameter for deconfinement and the chiral
condensate in SU(2) and SU(3) Yang-Mills theory in the vicinity of the
deconfinement phase transition using the Landau gauge quark and gluon
propagators. We determine the gluon propagator from lattice calculations and
the quark propagator from its Dyson-Schwinger equation, using the gluon
propagator as input. The critical temperature and a deconfinement order
parameter are extracted from the gluon propagator and from the dependency of
the quark propagator on the temporal boundary conditions. The chiral transition
is determined using the quark condensate as order parameter. We investigate
whether and how a difference in the chiral and deconfinement transition between
SU(2) and SU(3) is manifest.
| [
{
"created": "Tue, 9 Mar 2010 19:32:26 GMT",
"version": "v1"
},
{
"created": "Mon, 20 Sep 2010 10:19:56 GMT",
"version": "v2"
}
] | 2010-09-21 | [
[
"Fischer",
"Christian S.",
""
],
[
"Maas",
"Axel",
""
],
[
"Mueller",
"Jens A.",
""
]
] | We study a gauge invariant order parameter for deconfinement and the chiral condensate in SU(2) and SU(3) Yang-Mills theory in the vicinity of the deconfinement phase transition using the Landau gauge quark and gluon propagators. We determine the gluon propagator from lattice calculations and the quark propagator from its Dyson-Schwinger equation, using the gluon propagator as input. The critical temperature and a deconfinement order parameter are extracted from the gluon propagator and from the dependency of the quark propagator on the temporal boundary conditions. The chiral transition is determined using the quark condensate as order parameter. We investigate whether and how a difference in the chiral and deconfinement transition between SU(2) and SU(3) is manifest. |
hep-ph/0209070 | Mikhail Vysotsky | M. Vysotsky | $\mu_\nu$ | Review talk at the workshop ``Search for Dark Matter and Neutrino
Magnetic Moment'', ITEP, 11.12.2001 | Mod.Phys.Lett. A18 (2003) 877-884 | 10.1142/S0217732303010764 | preprint ITEP 17-02 | hep-ph hep-ex nucl-ex | null | The present situation and hopes on bounding (founding) neutrino magnetic
moment in future are reviewed.
| [
{
"created": "Fri, 6 Sep 2002 09:59:38 GMT",
"version": "v1"
}
] | 2009-11-07 | [
[
"Vysotsky",
"M.",
""
]
] | The present situation and hopes on bounding (founding) neutrino magnetic moment in future are reviewed. |
hep-ph/0008288 | Antonio Lopez Maroto | Antonio L. Maroto | Primordial magnetic fields from metric perturbations | 10 pages, 1 figure. Final version to appear in Phys. Rev. D | Phys.Rev.D64:083006,2001 | 10.1103/PhysRevD.64.083006 | CERN-TH/2000-258 | hep-ph astro-ph gr-qc | null | We study the amplification of electromagnetic vacuum fluctuations induced by
the evolution of scalar metric perturbations at the end of inflation. Such
perturbations break the conformal invariance of Maxwell equations in
Friedmann-Robertson-Walker backgrounds and allow the growth of magnetic fields
on super-Hubble scales. We relate the strength of the fields generated by this
mechanism with the power spectrum of scalar perturbations and estimate the
amplification on galactic scales for different values of the spectral index.
Finally we discuss the possible effects of finite conductivity during
reheating.
| [
{
"created": "Mon, 28 Aug 2000 13:41:02 GMT",
"version": "v1"
},
{
"created": "Thu, 18 Jan 2001 15:06:30 GMT",
"version": "v2"
},
{
"created": "Tue, 17 Jul 2001 14:16:33 GMT",
"version": "v3"
}
] | 2008-11-26 | [
[
"Maroto",
"Antonio L.",
""
]
] | We study the amplification of electromagnetic vacuum fluctuations induced by the evolution of scalar metric perturbations at the end of inflation. Such perturbations break the conformal invariance of Maxwell equations in Friedmann-Robertson-Walker backgrounds and allow the growth of magnetic fields on super-Hubble scales. We relate the strength of the fields generated by this mechanism with the power spectrum of scalar perturbations and estimate the amplification on galactic scales for different values of the spectral index. Finally we discuss the possible effects of finite conductivity during reheating. |
2207.08510 | Jobin Sebastian | Jobin Sebastian, Mohammad Yousuf Jamal and Najmul Haque | Li\'enard-Wiechert potential of a heavy quark moving in QGP medium | 10 pages, 7 figures | Phys.Rev.D 107 (2023), 054040 | 10.1103/PhysRevD.107.054040 | null | hep-ph nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We investigate the nature of the complex retarded potential of a heavy
quarkonium moving in a hot and dense static deconfined nuclear medium. The
well-known concept of the retarded potential in electrodynamics is extended to
the context of the heavy-quark by modifying the static vacuum Cornell potential
through Lorentz transformation to the static frame of the medium. The resulting
potential in the vacuum is further corrected to incorporate the screening
effect offered by the thermal medium. To do so, the retarded Cornell potential
is modified by the dielectric function of the static quark-gluon plasma (QGP)
medium. We present the numerical results for the real and imaginary parts of
the potential along with the analytical expression of the potential
approximated by a small velocity limit. Finally, we present the thermal width
of quarkonia in the QGP medium derived using the imaginary part of the
potential and study its dependence on velocity and temperature.
| [
{
"created": "Mon, 18 Jul 2022 11:04:04 GMT",
"version": "v1"
},
{
"created": "Mon, 3 Apr 2023 09:54:45 GMT",
"version": "v2"
}
] | 2023-04-04 | [
[
"Sebastian",
"Jobin",
""
],
[
"Jamal",
"Mohammad Yousuf",
""
],
[
"Haque",
"Najmul",
""
]
] | We investigate the nature of the complex retarded potential of a heavy quarkonium moving in a hot and dense static deconfined nuclear medium. The well-known concept of the retarded potential in electrodynamics is extended to the context of the heavy-quark by modifying the static vacuum Cornell potential through Lorentz transformation to the static frame of the medium. The resulting potential in the vacuum is further corrected to incorporate the screening effect offered by the thermal medium. To do so, the retarded Cornell potential is modified by the dielectric function of the static quark-gluon plasma (QGP) medium. We present the numerical results for the real and imaginary parts of the potential along with the analytical expression of the potential approximated by a small velocity limit. Finally, we present the thermal width of quarkonia in the QGP medium derived using the imaginary part of the potential and study its dependence on velocity and temperature. |
hep-ph/0110253 | James Simone | Shoji Hashimoto, Andreas S. Kronfeld, Paul B. Mackenzie, Sinead M.
Ryan and James N. Simone | Lattice calculation of the zero-recoil form factor of anti-B --> D*
lepton anti-neutrino: toward a model independent determination of |V(cb)| | 31 pages, 9 eps figures, RevTeX; PACS numbers: 12.38.Gc, 12.15.Hh,
13.20.He | Phys.Rev.D66:014503,2002 | 10.1103/PhysRevD.66.014503 | FERMILAB-PUB-01/317-T | hep-ph hep-lat | null | We develop a new method in lattice QCD to calculate the form factor F(1) at
zero recoil. This is the main theoretical ingredient needed to determine
|V(cb)| from the exclusive decay anti-B --> D* lepton anti-neutrino. We
introduce three ratios, in which most of statistical and systematic error
cancels, making a precise calculation possible. We fit the heavy-quark mass
dependence directly, and extract the 1/m_Q^2 and three of the four 1/m_Q^3
corrections in the heavy-quark expansion. In this paper we show how the method
works in the quenched approximation, obtaining F(1) = 0.913
(+0.024-0.017)(+/-0.016)(+0.003-0.014)(+0.000-0.016)(+0.006-0.014) where the
uncertainties come, respectively, from statistics and fitting, matching lattice
gauge theory to QCD, lattice spacing dependence, light quark mass effects, and
the quenched approximation. We also discuss how to reduce these uncertainties
and, thus, to obtain a model-independent determination of |V(cb)|.
| [
{
"created": "Thu, 18 Oct 2001 14:39:45 GMT",
"version": "v1"
}
] | 2014-11-17 | [
[
"Hashimoto",
"Shoji",
""
],
[
"Kronfeld",
"Andreas S.",
""
],
[
"Mackenzie",
"Paul B.",
""
],
[
"Ryan",
"Sinead M.",
""
],
[
"Simone",
"James N.",
""
]
] | We develop a new method in lattice QCD to calculate the form factor F(1) at zero recoil. This is the main theoretical ingredient needed to determine |V(cb)| from the exclusive decay anti-B --> D* lepton anti-neutrino. We introduce three ratios, in which most of statistical and systematic error cancels, making a precise calculation possible. We fit the heavy-quark mass dependence directly, and extract the 1/m_Q^2 and three of the four 1/m_Q^3 corrections in the heavy-quark expansion. In this paper we show how the method works in the quenched approximation, obtaining F(1) = 0.913 (+0.024-0.017)(+/-0.016)(+0.003-0.014)(+0.000-0.016)(+0.006-0.014) where the uncertainties come, respectively, from statistics and fitting, matching lattice gauge theory to QCD, lattice spacing dependence, light quark mass effects, and the quenched approximation. We also discuss how to reduce these uncertainties and, thus, to obtain a model-independent determination of |V(cb)|. |
hep-ph/0505245 | Leonid Satarov | L.M. Satarov, H. Stoecker, I.N. Mishustin | Mach shocks induced by partonic jets in expanding quark-gluon plasma | 13 pages, 4 figures | Phys.Lett. B627 (2005) 64-70 | 10.1016/j.physletb.2005.08.102 | null | hep-ph | null | We study Mach shocks generated by fast partonic jets propagating through a
deconfined strongly-interacting matter. Our main goal is to take into account
different types of collective motion during the formation and evolution of this
matter. We predict a significant deformation of Mach shocks in central Au+Au
collisions at RHIC and LHC energies as compared to the case of jet propagation
in a static medium. The observed broadening of the near-side two-particle
correlations in pseudorapidity space is explained by the Bjorken-like
longitudinal expansion. Three-particle correlation measurements are proposed
for a more detailed study of the Mach shock waves.
| [
{
"created": "Sun, 29 May 2005 14:37:18 GMT",
"version": "v1"
}
] | 2009-11-11 | [
[
"Satarov",
"L. M.",
""
],
[
"Stoecker",
"H.",
""
],
[
"Mishustin",
"I. N.",
""
]
] | We study Mach shocks generated by fast partonic jets propagating through a deconfined strongly-interacting matter. Our main goal is to take into account different types of collective motion during the formation and evolution of this matter. We predict a significant deformation of Mach shocks in central Au+Au collisions at RHIC and LHC energies as compared to the case of jet propagation in a static medium. The observed broadening of the near-side two-particle correlations in pseudorapidity space is explained by the Bjorken-like longitudinal expansion. Three-particle correlation measurements are proposed for a more detailed study of the Mach shock waves. |
hep-ph/0703062 | Feng-Kun Guo | Feng-Kun Guo, Peng-Nian Shen, Zhi-Gang Wang, Wei-Hong Liang, and L.S.
Kisslinger | Light vector hybrid states via QCD sum rules | 7 pages, 1 figure | null | null | null | hep-ph hep-ex | null | Vector hybrid states with light quarks $u,d,s$ are investigated via QCD sum
rules. The results show that the masses of the $q{\bar q}g$ $(q=u,d)$, $q{\bar
s}g$, and $s{\bar s}g$ states with $J^{PC}=1^{--}$ are about 2.3-2.4, 2.3-2.5,
and 2.5-2.6 GeV, respectively. It suggests that the recently discovered Y(2175)
could not be a pure $s{\bar s}g$ vector hybrid state.
| [
{
"created": "Tue, 6 Mar 2007 15:55:01 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Guo",
"Feng-Kun",
""
],
[
"Shen",
"Peng-Nian",
""
],
[
"Wang",
"Zhi-Gang",
""
],
[
"Liang",
"Wei-Hong",
""
],
[
"Kisslinger",
"L. S.",
""
]
] | Vector hybrid states with light quarks $u,d,s$ are investigated via QCD sum rules. The results show that the masses of the $q{\bar q}g$ $(q=u,d)$, $q{\bar s}g$, and $s{\bar s}g$ states with $J^{PC}=1^{--}$ are about 2.3-2.4, 2.3-2.5, and 2.5-2.6 GeV, respectively. It suggests that the recently discovered Y(2175) could not be a pure $s{\bar s}g$ vector hybrid state. |
hep-ph/0310071 | Vladimir Kopeliovich Benedikt | Vladimir Kopeliovich (Moscow, INR) | Exotic baryons and multibaryons in chiral soliton models | 14 pages, 3 Fig. Presented at the International Symposium on
Electrophoto-production of Strangeness on Nucleons and Nuclei (Sendai, Japan,
June 16-18, 2003) | null | 10.1142/9789812702920_0009 | null | hep-ph | null | Recently observed exotic baryon resonance with positive strangeness is
discussed. The chiral soliton model, which allowed to predict the mass and
width of this state, predicts also a number of other exotic states, strange and
non-strange, some of them are, probably, observed in experiments. The existence
of exotic multibaryons is expected as well, with positive strangeness or
beauty, and negative charm. The possibility of binding of anticharm and
antibeauty is pointed out.
| [
{
"created": "Mon, 6 Oct 2003 16:43:50 GMT",
"version": "v1"
}
] | 2017-08-23 | [
[
"Kopeliovich",
"Vladimir",
"",
"Moscow, INR"
]
] | Recently observed exotic baryon resonance with positive strangeness is discussed. The chiral soliton model, which allowed to predict the mass and width of this state, predicts also a number of other exotic states, strange and non-strange, some of them are, probably, observed in experiments. The existence of exotic multibaryons is expected as well, with positive strangeness or beauty, and negative charm. The possibility of binding of anticharm and antibeauty is pointed out. |
hep-ph/0305001 | Olivier R. Espinosa | Olivier Espinosa, Edgardo Stockmeyer | An operator representation for Matsubara sums | 4 figures; references added, minor changes in notation, final version
accepted for publication | Phys.Rev. D69 (2004) 065004 | 10.1103/PhysRevD.69.065004 | null | hep-ph hep-th math-ph math.MP | null | In the context of the imaginary-time formalism for a scalar thermal field
theory, it is shown that the result of performing the sums over Matsubara
frequencies associated with loop Feynman diagrams can be written, for some
classes of diagrams, in terms of the action of a simple linear operator on the
corresponding energy integrals of the Euclidean theory at T=0. In its simplest
form the referred operator depends only on the number of internal propagators
of the graph.
More precisely, it is shown explicitly that this \emph{thermal operator
representation} holds for two generic classes of diagrams, namely, the
two-vertex diagram with an arbitrary number of internal propagators, and the
one-loop diagram with an arbitrary number of vertices.
The validity of the thermal operator representation for diagrams of more
complicated topologies remains an open problem. Its correctness is shown to be
equivalent to the correctness of some diagrammatic rules proposed a few years
ago.
| [
{
"created": "Wed, 30 Apr 2003 23:44:01 GMT",
"version": "v1"
},
{
"created": "Thu, 11 Dec 2003 17:35:38 GMT",
"version": "v2"
}
] | 2009-11-10 | [
[
"Espinosa",
"Olivier",
""
],
[
"Stockmeyer",
"Edgardo",
""
]
] | In the context of the imaginary-time formalism for a scalar thermal field theory, it is shown that the result of performing the sums over Matsubara frequencies associated with loop Feynman diagrams can be written, for some classes of diagrams, in terms of the action of a simple linear operator on the corresponding energy integrals of the Euclidean theory at T=0. In its simplest form the referred operator depends only on the number of internal propagators of the graph. More precisely, it is shown explicitly that this \emph{thermal operator representation} holds for two generic classes of diagrams, namely, the two-vertex diagram with an arbitrary number of internal propagators, and the one-loop diagram with an arbitrary number of vertices. The validity of the thermal operator representation for diagrams of more complicated topologies remains an open problem. Its correctness is shown to be equivalent to the correctness of some diagrammatic rules proposed a few years ago. |
hep-ph/0503030 | Mary Hall Reno | M. H. Reno (Iowa), I. Sarcevic (Arizona), S. Su (Arizona) | Propagation of supersymmetric charged sleptons at high energies | 7 pages, 8 figures, version accepted for publication in Astroparticle
Physics | Astropart.Phys. 24 (2005) 107-115 | 10.1016/j.astropartphys.2005.06.002 | null | hep-ph astro-ph | null | The potential for neutrino telescopes to discover charged stau production in
neutrino-nucleon interactions in Earth depends in part on the stau lifetime and
range. In some supersymmetric scenarios, the next lightest supersymmetric
particle is a stau with a decay length on the scale of 10 km. We evaluate the
electromagnetic energy loss as a function of energy and stau mass. The energy
loss parameter $\beta$ scales as the inverse stau mass for the dominating
electromagnetic processes, photonuclear and $e^+e^-$ pair production. The range
can be parameterized as a function of stau mass, initial energy and minimum
final energy. In comparison to earlier estimates of the stau range, our results
are as much as a factor of two larger, improving the potential for stau
discovery in neutrino telescopes.
| [
{
"created": "Thu, 3 Mar 2005 17:45:50 GMT",
"version": "v1"
},
{
"created": "Thu, 30 Jun 2005 20:07:27 GMT",
"version": "v2"
}
] | 2009-11-11 | [
[
"Reno",
"M. H.",
"",
"Iowa"
],
[
"Sarcevic",
"I.",
"",
"Arizona"
],
[
"Su",
"S.",
"",
"Arizona"
]
] | The potential for neutrino telescopes to discover charged stau production in neutrino-nucleon interactions in Earth depends in part on the stau lifetime and range. In some supersymmetric scenarios, the next lightest supersymmetric particle is a stau with a decay length on the scale of 10 km. We evaluate the electromagnetic energy loss as a function of energy and stau mass. The energy loss parameter $\beta$ scales as the inverse stau mass for the dominating electromagnetic processes, photonuclear and $e^+e^-$ pair production. The range can be parameterized as a function of stau mass, initial energy and minimum final energy. In comparison to earlier estimates of the stau range, our results are as much as a factor of two larger, improving the potential for stau discovery in neutrino telescopes. |
hep-ph/0403216 | Daniel Boyanovsky | D. Boyanovsky and C. M. Ho | Oscillations and evolution of a hot and dense gas of flavor neutrinos: a
quantum field theory study | 28 pages, 3 eps figs. version accepted in PRD | Phys.Rev. D69 (2004) 125012 | 10.1103/PhysRevD.69.125012 | null | hep-ph | null | We study the time evolution of the distribution functions for hot and or
degenerate gases of two flavors of Dirac neutrinos as a result of flavor mixing
and dephasing. This is achieved by obtaining the time evolution of the flavor
density matrix directly from quantum field theory at finite temperature and
density. The time evolution features a rich hierarchy of scales which are
widely separated in the nearly degenerate or relativistic cases and originate
in interference phenomena between particle and antiparticle states. In the
degenerate case the flavor asymmetry $\Delta N(t)$ relaxes to the asymptotic
limit $\Delta N(\infty)=\Delta N(0)\cos^2(2\theta)$ via dephasing resulting
from the oscillations between flavor modes that are not Pauli blocked, with a
power law $1/t$ for $t>t_s \approx 2 k_F/\Delta M^2$. $k_F$ is the largest of
the Fermi momenta. The distribution function for flavor neutrinos and
antineutrinos as well as off-diagonal densities are obtained. Flavor
particle-antiparticle pairs are produced by mixing and oscillations with
typical momentum $k\sim \bar{M}$ the average mass of the neutrinos. An
effective field theory description emerges on long time scales in which the
Heisenberg operators obey a Bloch-type equation of motion valid in the
relativistic and nearly degenerate cases. We find the non-equilibrium
propagators and correlation functions in this effective theory and discuss its
regime of validity as well as the potential corrections.
| [
{
"created": "Fri, 19 Mar 2004 16:42:26 GMT",
"version": "v1"
},
{
"created": "Fri, 9 Apr 2004 19:30:11 GMT",
"version": "v2"
}
] | 2009-11-10 | [
[
"Boyanovsky",
"D.",
""
],
[
"Ho",
"C. M.",
""
]
] | We study the time evolution of the distribution functions for hot and or degenerate gases of two flavors of Dirac neutrinos as a result of flavor mixing and dephasing. This is achieved by obtaining the time evolution of the flavor density matrix directly from quantum field theory at finite temperature and density. The time evolution features a rich hierarchy of scales which are widely separated in the nearly degenerate or relativistic cases and originate in interference phenomena between particle and antiparticle states. In the degenerate case the flavor asymmetry $\Delta N(t)$ relaxes to the asymptotic limit $\Delta N(\infty)=\Delta N(0)\cos^2(2\theta)$ via dephasing resulting from the oscillations between flavor modes that are not Pauli blocked, with a power law $1/t$ for $t>t_s \approx 2 k_F/\Delta M^2$. $k_F$ is the largest of the Fermi momenta. The distribution function for flavor neutrinos and antineutrinos as well as off-diagonal densities are obtained. Flavor particle-antiparticle pairs are produced by mixing and oscillations with typical momentum $k\sim \bar{M}$ the average mass of the neutrinos. An effective field theory description emerges on long time scales in which the Heisenberg operators obey a Bloch-type equation of motion valid in the relativistic and nearly degenerate cases. We find the non-equilibrium propagators and correlation functions in this effective theory and discuss its regime of validity as well as the potential corrections. |
1903.11602 | Pablo Guerrero-Rodr\'iguez | Pablo Guerrero-Rodr\'iguez | Topological charge fluctuations in the Glasma | arXiv admin note: text overlap with arXiv:1808.00795 | null | 10.1007/JHEP08(2019)026 | null | hep-ph nucl-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The early-time evolution of the system generated in ultra-relativistic heavy
ion collisions is dominated by the presence of strong color fields known as
Glasma fields. These can be described following the classical approach embodied
in the Color Glass Condensate effective theory, which approximates QCD in the
high gluon density regime. In this framework we perform an analytical
first-principles calculation of the two-point correlator of the divergence of
the Chern-Simons current at proper time $\tau\!=\!0^+$, which characterizes the
early fluctuations of axial charge density in the plane transverse to the
collision axis. This object plays a crucial role in the description of
anomalous transport phenomena such as the Chiral Magnetic Effect. We compare
our results to those obtained under the Glasma Graph approximation, which
assumes gluon field correlators to obey Gaussian statistics. While this
approach proves to be equivalent to the exact calculation in the limit of short
transverse separations, important differences arise at larger distances, where
our expression displays a remarkably slower fall-off than the Glasma Graph
result ($1/r^4$ vs.\ $1/r^8$ power-law decay). This discrepancy emerges from
the non-linear dynamics mapping the Gaussianly-distributed color source
densities onto the Glasma fields, encoded in the classical Yang-Mills
equations. Our results support the conclusions reached in a previous work,
where we found indications that the color screening of correlations in the
transverse plane occurs at relatively large distances.
| [
{
"created": "Wed, 27 Mar 2019 16:52:09 GMT",
"version": "v1"
}
] | 2019-09-04 | [
[
"Guerrero-Rodríguez",
"Pablo",
""
]
] | The early-time evolution of the system generated in ultra-relativistic heavy ion collisions is dominated by the presence of strong color fields known as Glasma fields. These can be described following the classical approach embodied in the Color Glass Condensate effective theory, which approximates QCD in the high gluon density regime. In this framework we perform an analytical first-principles calculation of the two-point correlator of the divergence of the Chern-Simons current at proper time $\tau\!=\!0^+$, which characterizes the early fluctuations of axial charge density in the plane transverse to the collision axis. This object plays a crucial role in the description of anomalous transport phenomena such as the Chiral Magnetic Effect. We compare our results to those obtained under the Glasma Graph approximation, which assumes gluon field correlators to obey Gaussian statistics. While this approach proves to be equivalent to the exact calculation in the limit of short transverse separations, important differences arise at larger distances, where our expression displays a remarkably slower fall-off than the Glasma Graph result ($1/r^4$ vs.\ $1/r^8$ power-law decay). This discrepancy emerges from the non-linear dynamics mapping the Gaussianly-distributed color source densities onto the Glasma fields, encoded in the classical Yang-Mills equations. Our results support the conclusions reached in a previous work, where we found indications that the color screening of correlations in the transverse plane occurs at relatively large distances. |
1111.2981 | Heather E. Logan | Heather E. Logan (Carleton U.) | LHC Phenomenology | 8 pages, no figures, invited plenary talk at XXXI Physics In
Collision, Vancouver, Canada, Aug 28-Sep 1, 2011 | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The analyses of the first 1-2/fb of Large Hadron Collider (LHC) data are
already having significant impacts on a wide range of models. In this talk I
give my perspective on why we expect to find new physics at the LHC, and how
such a discovery might unfold.
| [
{
"created": "Sun, 13 Nov 2011 01:22:34 GMT",
"version": "v1"
}
] | 2011-11-15 | [
[
"Logan",
"Heather E.",
"",
"Carleton U."
]
] | The analyses of the first 1-2/fb of Large Hadron Collider (LHC) data are already having significant impacts on a wide range of models. In this talk I give my perspective on why we expect to find new physics at the LHC, and how such a discovery might unfold. |
hep-ph/0312324 | Carl R. Schmidt | Roshan Foadi, Shrihari Gopalakrishna, Carl Schmidt | Higgsless Electroweak Symmetry Breaking from Theory Space | 21 pages, 8 figures, JHEP format (published version, some minor
clarifying sentences added) | JHEP 0403 (2004) 042 | 10.1088/1126-6708/2004/03/042 | MSUHEP-031216 | hep-ph | null | We investigate unitarity of $W^+W^-$ scattering in the context of theory
space models of the form $U(1)\times {[SU(2)]}^N\times SU(2)_{N+1}$, which are
broken down to $U(1)_{EM}$ by non-linear $\Sigma$ fields, without the presence
of a physical Higgs Boson. By allowing the couplings of the U(1) and the final
$SU(2)_{N+1}$ to vary, we can fit the $W$ and $Z$ masses, and we find that the
coefficient of the term in the amplitude that grows as $E^2/m_W^2$ at high
energies is suppressed by a factor of $(N+1)^{-2}$. In the $N+1\to\infty$ limit
the model becomes a 5-dimensional SU(2) gauge theory defined on an interval,
where boundary terms at the two ends of the interval break the SU(2) down to
$U(1)_{EM}$. These boundary terms also modify the Kaluza-Klein (KK) mass
spectrum, so that the lightest KK states can be identified as the $W$ and $Z$
bosons. The $T$ parameter, which measures custodial symmetry breaking, is
naturally small in these models. Depending on how matter fields are included,
the strongest experimental constraints come from precision electroweak limits
on the $S$ parameter.
| [
{
"created": "Mon, 22 Dec 2003 21:44:04 GMT",
"version": "v1"
},
{
"created": "Sat, 27 Mar 2004 19:19:13 GMT",
"version": "v2"
}
] | 2009-11-10 | [
[
"Foadi",
"Roshan",
""
],
[
"Gopalakrishna",
"Shrihari",
""
],
[
"Schmidt",
"Carl",
""
]
] | We investigate unitarity of $W^+W^-$ scattering in the context of theory space models of the form $U(1)\times {[SU(2)]}^N\times SU(2)_{N+1}$, which are broken down to $U(1)_{EM}$ by non-linear $\Sigma$ fields, without the presence of a physical Higgs Boson. By allowing the couplings of the U(1) and the final $SU(2)_{N+1}$ to vary, we can fit the $W$ and $Z$ masses, and we find that the coefficient of the term in the amplitude that grows as $E^2/m_W^2$ at high energies is suppressed by a factor of $(N+1)^{-2}$. In the $N+1\to\infty$ limit the model becomes a 5-dimensional SU(2) gauge theory defined on an interval, where boundary terms at the two ends of the interval break the SU(2) down to $U(1)_{EM}$. These boundary terms also modify the Kaluza-Klein (KK) mass spectrum, so that the lightest KK states can be identified as the $W$ and $Z$ bosons. The $T$ parameter, which measures custodial symmetry breaking, is naturally small in these models. Depending on how matter fields are included, the strongest experimental constraints come from precision electroweak limits on the $S$ parameter. |
1004.1607 | Wschebor Nicolas | Matthieu Tissier and Nicolas Wschebor | Infrared propagators of Yang-Mills theory from perturbation theory | 4 pages, 4 figures. | Phys.Rev.D82:101701,2010 | 10.1103/PhysRevD.82.101701 | null | hep-ph hep-lat hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We show that the correlation functions of ghosts and gluons for the pure
Yang-Mills theory in Landau gauge can be accurately reproduced for all momenta
by a one-loop calculation. The key point is to use a massive extension of the
Faddeev-Popov action. The agreement with lattice simulation is excellent in
d=4. The one-loop calculation also reproduces all the characteristic features
of the lattice simulations in d=3 and naturally explains the pecularities of
the propagators in d=2.
| [
{
"created": "Fri, 9 Apr 2010 17:05:24 GMT",
"version": "v1"
}
] | 2010-11-11 | [
[
"Tissier",
"Matthieu",
""
],
[
"Wschebor",
"Nicolas",
""
]
] | We show that the correlation functions of ghosts and gluons for the pure Yang-Mills theory in Landau gauge can be accurately reproduced for all momenta by a one-loop calculation. The key point is to use a massive extension of the Faddeev-Popov action. The agreement with lattice simulation is excellent in d=4. The one-loop calculation also reproduces all the characteristic features of the lattice simulations in d=3 and naturally explains the pecularities of the propagators in d=2. |
2405.03996 | Junichiro Kawamura | Tae Hyun Jung and Junichiro Kawamura | Finite modular majoron | 21 pages, 5 figures | null | null | CTPU-PTC-24-13 | hep-ph astro-ph.CO hep-ex hep-th | http://creativecommons.org/licenses/by/4.0/ | We point out that the accidental $U(1)_{B-L}$ symmetry can arise from a
finite modular symmetry $\Gamma_N$ in the type-I seesaw. The finite modular
symmetry is spontaneously broken in such a way that the residual
$\mathbb{Z}^T_N$ discrete symmetry, associated with the $T$-transformation
which shifts the modulus $\tau \to \tau+ 1$, remains unbroken. This discrete
$\mathbb{Z}^T_N$ symmetry mimics $U(1)_{B-L}$, and hence the majoron appears as
a pseudo Nambu-Goldstone boson of $U(1)_{B-L}$. Without introducing additional
interactions, the modulus $\tau$ can be stabilized by the Coleman-Weinberg (CW)
potential given by the Majorana mass terms of the right-handed neutrinos. We
study cosmological implications of the majoron, with particular interests in
the dark matter and dark radiation, where the latter may alleviate the Hubble
tension. We also find that the CW potential can have a wide range of nearly
exponential shape which prevents $\tau$ from overshooting, and makes the amount
of dark radiation not too large.
| [
{
"created": "Tue, 7 May 2024 04:19:07 GMT",
"version": "v1"
}
] | 2024-05-08 | [
[
"Jung",
"Tae Hyun",
""
],
[
"Kawamura",
"Junichiro",
""
]
] | We point out that the accidental $U(1)_{B-L}$ symmetry can arise from a finite modular symmetry $\Gamma_N$ in the type-I seesaw. The finite modular symmetry is spontaneously broken in such a way that the residual $\mathbb{Z}^T_N$ discrete symmetry, associated with the $T$-transformation which shifts the modulus $\tau \to \tau+ 1$, remains unbroken. This discrete $\mathbb{Z}^T_N$ symmetry mimics $U(1)_{B-L}$, and hence the majoron appears as a pseudo Nambu-Goldstone boson of $U(1)_{B-L}$. Without introducing additional interactions, the modulus $\tau$ can be stabilized by the Coleman-Weinberg (CW) potential given by the Majorana mass terms of the right-handed neutrinos. We study cosmological implications of the majoron, with particular interests in the dark matter and dark radiation, where the latter may alleviate the Hubble tension. We also find that the CW potential can have a wide range of nearly exponential shape which prevents $\tau$ from overshooting, and makes the amount of dark radiation not too large. |
hep-ph/0309269 | Matthias Burkardt | Matthias Burkardt (New Mexico State University) | Chromodynamic Lensing and $\perp$ Single Spin Asymmetries | 8 pages, invited talk given at workshop on `light-cone 2003: Hadrons
and Beyond' (Durham, August 2003) and at `NAPP 2003' (Dubrovnik, Croatia, May
2003) | Fizika B13 (2004) 565-576 | null | null | hep-ph | null | The physical interpretation of generalized parton distributions (in the limit
$\xi=0$) as Fourier transforms of impact parameter dependent parton
distributions is discussed. Particular emphasis is put on the role of the
target polarization. For transversely polarized targets we expect a significant
deviation from axial symmetry for the distribution in the transverse plane. We
conjecture that this transverse distortion, in combination with the final state
provides a natural explanation for the sign of the Sivers contribution to
semi-inclusive single-spin asymmetries.
| [
{
"created": "Tue, 23 Sep 2003 23:54:33 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Burkardt",
"Matthias",
"",
"New Mexico State University"
]
] | The physical interpretation of generalized parton distributions (in the limit $\xi=0$) as Fourier transforms of impact parameter dependent parton distributions is discussed. Particular emphasis is put on the role of the target polarization. For transversely polarized targets we expect a significant deviation from axial symmetry for the distribution in the transverse plane. We conjecture that this transverse distortion, in combination with the final state provides a natural explanation for the sign of the Sivers contribution to semi-inclusive single-spin asymmetries. |
1509.01249 | Robert Ziegler | Adam Falkowski, Marco Nardecchia, Robert Ziegler | Lepton Flavor Non-Universality in B-meson Decays from a U(2) Flavor
Model | 23 pages, 2 figures, references added, matches published version | null | 10.1007/JHEP11(2015)173 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We address the recent anomalies in semi-leptonic $B$-meson decays using a
model of fermion masses based on the $U(2)$ flavor symmetry. The new
contributions to $b \to s \ell \ell$ transitions arise due to a tree-level
exchange of a $Z^\prime$ vector boson gauging a $U(1)$ subgroup of the flavor
symmetry. They are controlled by a single parameter and are approximately
aligned to the Standard Model prediction, with constructive interference in the
$e$-channel and destructive interference in the $\mu$-channel. The current
experimental data on semi-leptonic $B$-meson decays can be very well reproduced
without violating existing constraints from flavor violation in the quark and
lepton sectors. Our model will be tested by new measurements of $b \to s \ell
\ell$ transitions and also by future electroweak precision tests, direct
$Z^\prime$ searches, and $\mu$-$e$ conversion in nuclei.
| [
{
"created": "Thu, 3 Sep 2015 20:04:18 GMT",
"version": "v1"
},
{
"created": "Tue, 10 Nov 2015 10:15:23 GMT",
"version": "v2"
}
] | 2016-01-20 | [
[
"Falkowski",
"Adam",
""
],
[
"Nardecchia",
"Marco",
""
],
[
"Ziegler",
"Robert",
""
]
] | We address the recent anomalies in semi-leptonic $B$-meson decays using a model of fermion masses based on the $U(2)$ flavor symmetry. The new contributions to $b \to s \ell \ell$ transitions arise due to a tree-level exchange of a $Z^\prime$ vector boson gauging a $U(1)$ subgroup of the flavor symmetry. They are controlled by a single parameter and are approximately aligned to the Standard Model prediction, with constructive interference in the $e$-channel and destructive interference in the $\mu$-channel. The current experimental data on semi-leptonic $B$-meson decays can be very well reproduced without violating existing constraints from flavor violation in the quark and lepton sectors. Our model will be tested by new measurements of $b \to s \ell \ell$ transitions and also by future electroweak precision tests, direct $Z^\prime$ searches, and $\mu$-$e$ conversion in nuclei. |
0712.0903 | Cecilia Jarlskog | C. Jarlskog | Neutrino Sector with Majorana Mass Terms and Friedberg-Lee Symmetry | null | Phys.Rev.D77:073002,2008 | 10.1103/PhysRevD.77.073002 | null | hep-ph | null | We examine a recently proposed symmetry/condition by Friedberg and Lee in the
framework where three right-handed neutrinos are added to the spectrum of the
three-family Minimal Standard Model. It is found that the right-handed
neutrinos are very special, with respect to this symmetry. In the symmetry
limit the neutrinos are massless and that may be a hint about why they are
light. Imposed as a condition and not as a full symmetry, we find that one of
the three right-handed neutrinos simply decouples (has only gravitational
interactions) and that there is a massless interacting neutrino. The possible
relation of the model to the see-saw mechanism is briefly discussed.
| [
{
"created": "Thu, 6 Dec 2007 10:29:23 GMT",
"version": "v1"
}
] | 2008-11-26 | [
[
"Jarlskog",
"C.",
""
]
] | We examine a recently proposed symmetry/condition by Friedberg and Lee in the framework where three right-handed neutrinos are added to the spectrum of the three-family Minimal Standard Model. It is found that the right-handed neutrinos are very special, with respect to this symmetry. In the symmetry limit the neutrinos are massless and that may be a hint about why they are light. Imposed as a condition and not as a full symmetry, we find that one of the three right-handed neutrinos simply decouples (has only gravitational interactions) and that there is a massless interacting neutrino. The possible relation of the model to the see-saw mechanism is briefly discussed. |
0706.3875 | Fritz W. Bopp | J.Ranft, F.W.Bopp, R.Engel and S.Roesler | Inclusive distributions at the LHC as predicted from the DPMJET-III
model with chain fusion | Presented at "Heavy Ion Collisions at the LHC: last call for
predictions", Geneva Switzerland, May 14th-June 8th | null | null | SI-HEP-2007-10 | hep-ph | null | DPMJET-III with chain fusion is used to calculate inclusive distributions of
Pb-Pb collisions at LHC energies. We present rapidity distributions as well as
scaled multiplicities at mid-rapidity as function of the collision energy and
the number of participants.
| [
{
"created": "Tue, 26 Jun 2007 17:01:09 GMT",
"version": "v1"
}
] | 2007-06-27 | [
[
"Ranft",
"J.",
""
],
[
"Bopp",
"F. W.",
""
],
[
"Engel",
"R.",
""
],
[
"Roesler",
"S.",
""
]
] | DPMJET-III with chain fusion is used to calculate inclusive distributions of Pb-Pb collisions at LHC energies. We present rapidity distributions as well as scaled multiplicities at mid-rapidity as function of the collision energy and the number of participants. |
2003.12272 | Sukadev Sahoo | P. Maji, S. Mahata, P. Nayek, S. Biswas and S. Sahoo | Investigation of rare semileptonic $ B_c$ decays into
$(D_(s,d)^((*))){\mu}^+ {\mu}^-$ decays with non-universal $ Z'$ effect | Accepted for publication in Chinese Physics C | Chinese Physics C, 2020 | 10.1088/1674-1137/44/7/073106 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this paper, we analyze different decay observables of semileptonic $ B_c$
decays into $(D_(s,d)^((*))){\mu}^+ {\mu}^-$ such as branching ratio,
forward-backward asymmetry, polarization fraction and lepton polarization
asymmetry in the non-universal Z' model. We have also studied the dependence of
branching fraction to the new model parameters. Here, we have found that the
values of different decay parameters increase in the Z' model, which provides a
possible way out for the search of new physics as well as the unknown phenomena
of charm B meson.
| [
{
"created": "Fri, 27 Mar 2020 08:15:03 GMT",
"version": "v1"
}
] | 2020-08-26 | [
[
"Maji",
"P.",
""
],
[
"Mahata",
"S.",
""
],
[
"Nayek",
"P.",
""
],
[
"Biswas",
"S.",
""
],
[
"Sahoo",
"S.",
""
]
] | In this paper, we analyze different decay observables of semileptonic $ B_c$ decays into $(D_(s,d)^((*))){\mu}^+ {\mu}^-$ such as branching ratio, forward-backward asymmetry, polarization fraction and lepton polarization asymmetry in the non-universal Z' model. We have also studied the dependence of branching fraction to the new model parameters. Here, we have found that the values of different decay parameters increase in the Z' model, which provides a possible way out for the search of new physics as well as the unknown phenomena of charm B meson. |
1604.03497 | Abdel Nasser Tawfik | Abdel Nasser Tawfik (Egyptian Ctr. Theor. Phys., Cairo, WLCAPP,
Cairo), L. I. Abou-Salem (Benha U.), Asmaa G. Shalaby, and M. Hanafy (Benha
U., WLCAPP, Cairo) | On dynamical net-charge fluctuations within a hadron resonance gas
approach | 8 pages, 1 figure, accepted for publication in Advances in High
Energy Physics | Adv.High Energy Phys. 2016 (2016) 2475916 | 10.1155/2016/2475916 | ECTP-2016-01, WLCAPP-2016-01 | hep-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The dynamical net-charge fluctuations (${\nu}_{dyn}$) in different particle
ratios $K/{\pi}$, $K/p$, and $p/{\pi}$ are calculated from the hadron resonance
gas (HRG) model and compared with STAR central Au+Au collisions at
$\sqrt{s_{NN}}=7.7-200~$GeV and NA49 central Pb+Pb collisions at
$\sqrt{s_{NN}}=6.3-17.3~$GeV. The three charged-particle ratios ($K/{\pi}$,
$K/p$, and $p/{\pi}$) are determined as total and average of opposite and
average of same charges. We find an excellent agreement between the HRG
calculations and the experimental measurements, especially from STAR beam
energy scan (BES) program, while the strange particles in the NA49 experiment
at lower Super Proton Synchrotron (SPS) energies are not reproduced by the HRG
approach. We conclude that the utilized HRG version seems to take into
consideration various types of correlations including strong interactions
through the heavy resonances and their decays especially at BES energies.
| [
{
"created": "Mon, 11 Apr 2016 14:28:44 GMT",
"version": "v1"
}
] | 2016-04-29 | [
[
"Tawfik",
"Abdel Nasser",
"",
"Egyptian Ctr. Theor. Phys., Cairo, WLCAPP,\n Cairo"
],
[
"Abou-Salem",
"L. I.",
"",
"Benha U."
],
[
"Shalaby",
"Asmaa G.",
"",
"Benha\n U., WLCAPP, Cairo"
],
[
"Hanafy",
"M.",
"",
"Benha\n U., WLCAPP, Cairo"
]
] | The dynamical net-charge fluctuations (${\nu}_{dyn}$) in different particle ratios $K/{\pi}$, $K/p$, and $p/{\pi}$ are calculated from the hadron resonance gas (HRG) model and compared with STAR central Au+Au collisions at $\sqrt{s_{NN}}=7.7-200~$GeV and NA49 central Pb+Pb collisions at $\sqrt{s_{NN}}=6.3-17.3~$GeV. The three charged-particle ratios ($K/{\pi}$, $K/p$, and $p/{\pi}$) are determined as total and average of opposite and average of same charges. We find an excellent agreement between the HRG calculations and the experimental measurements, especially from STAR beam energy scan (BES) program, while the strange particles in the NA49 experiment at lower Super Proton Synchrotron (SPS) energies are not reproduced by the HRG approach. We conclude that the utilized HRG version seems to take into consideration various types of correlations including strong interactions through the heavy resonances and their decays especially at BES energies. |
1809.07562 | Michael Andreas Schmidt | Shyam Balaji, Robert Foot, Michael A. Schmidt | A chiral SU(4) explanation of the $b\to s$ anomalies | 10 pages, 4 figures; references added, minor changes to match version
published in PRD | Phys. Rev. D 99, 015029 (2019) | 10.1103/PhysRevD.99.015029 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We propose a variant of the Pati-Salam model, with gauge group $SU(4)_C\times
SU(2)_L\times U(1)_{Y'}$, in which the chiral left-handed quarks and leptons
are unified into a $\underline{4}$ of $SU(4)_C$, while the right-handed quarks
and leptons have quite a distinct treatment. The $SU(4)_C$ leptoquark gauge
bosons can explain the measured deviation of lepton flavour universality in the
rare decays: $\bar B \to \bar K^{(*)}\bar\ell\ell, \ell=\mu,e$ (taken as a hint
of new physics). The model satisfies the relevant experimental constraints and
makes predictions for the important $B$ and $\tau$ decays. These predictions
will be tested at the LHCb and Belle II experiments when increased statistics
become available.
| [
{
"created": "Thu, 20 Sep 2018 10:44:02 GMT",
"version": "v1"
},
{
"created": "Sat, 12 Jan 2019 00:14:08 GMT",
"version": "v2"
}
] | 2019-01-30 | [
[
"Balaji",
"Shyam",
""
],
[
"Foot",
"Robert",
""
],
[
"Schmidt",
"Michael A.",
""
]
] | We propose a variant of the Pati-Salam model, with gauge group $SU(4)_C\times SU(2)_L\times U(1)_{Y'}$, in which the chiral left-handed quarks and leptons are unified into a $\underline{4}$ of $SU(4)_C$, while the right-handed quarks and leptons have quite a distinct treatment. The $SU(4)_C$ leptoquark gauge bosons can explain the measured deviation of lepton flavour universality in the rare decays: $\bar B \to \bar K^{(*)}\bar\ell\ell, \ell=\mu,e$ (taken as a hint of new physics). The model satisfies the relevant experimental constraints and makes predictions for the important $B$ and $\tau$ decays. These predictions will be tested at the LHCb and Belle II experiments when increased statistics become available. |
1405.6308 | Alexei P. Martynenko | R.N. Faustov (Dorodnicyn Computing Centre), A.P. Martynenko (Samara
State U. and Samara State Aerospace U.), G.A. Martynenko and V.V. Sorokin
(Samara State U.) | Hyperfine structure of S-states in muonic deuterium | 18 pages, 7 figures | Phys. Rev. A 90, 012520 (2014) | 10.1103/PhysRevA.90.012520 | SSU-HEP-14/06 | hep-ph quant-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | On the basis of quasipotential method in quantum electrodynamics we calculate
corrections of order $\alpha^5$ and $\alpha^6$ to hyperfine structure of S-wave
energy levels of muonic deuterium. Relativistic corrections, effects of vacuum
polarization in first, second and third orders of perturbation theory, nuclear
structure and recoil corrections are taken into account. The obtained numerical
values of hyperfine splitting $\Delta E^{hfs}(1S)=50.2814$ meV (1S state) and
$\Delta E^{hfs}(2S)=6.2804$ meV (2S state) represent reliable estimate for a
comparison with forthcoming experimental data of CREMA collaboration. The
hyperfine structure interval $\Delta_{12}=8\Delta E^{hfs}(2S)-\Delta
E^{hfs}(1S)=-0.0379$ meV can be used for precision check of quantum
electrodynamics predictions for muonic deterium.
| [
{
"created": "Sat, 24 May 2014 14:57:06 GMT",
"version": "v1"
},
{
"created": "Thu, 29 May 2014 14:06:50 GMT",
"version": "v2"
}
] | 2014-07-30 | [
[
"Faustov",
"R. N.",
"",
"Dorodnicyn Computing Centre"
],
[
"Martynenko",
"A. P.",
"",
"Samara\n State U. and Samara State Aerospace U."
],
[
"Martynenko",
"G. A.",
"",
"Samara State U."
],
[
"Sorokin",
"V. V.",
"",
"Samara State U."
]
] | On the basis of quasipotential method in quantum electrodynamics we calculate corrections of order $\alpha^5$ and $\alpha^6$ to hyperfine structure of S-wave energy levels of muonic deuterium. Relativistic corrections, effects of vacuum polarization in first, second and third orders of perturbation theory, nuclear structure and recoil corrections are taken into account. The obtained numerical values of hyperfine splitting $\Delta E^{hfs}(1S)=50.2814$ meV (1S state) and $\Delta E^{hfs}(2S)=6.2804$ meV (2S state) represent reliable estimate for a comparison with forthcoming experimental data of CREMA collaboration. The hyperfine structure interval $\Delta_{12}=8\Delta E^{hfs}(2S)-\Delta E^{hfs}(1S)=-0.0379$ meV can be used for precision check of quantum electrodynamics predictions for muonic deterium. |
1012.1562 | Margarete Muhlleitner | Ramona Grober, Margarete Muhlleitner | Composite Higgs Boson Pair Production at the LHC | null | JHEP 1106:020,2011 | 10.1007/JHEP06(2011)020 | KA-TP-37-2010 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The measurement of the trilinear and quartic Higgs self-couplings is
necessary for the reconstruction of the Higgs potential. This way the Higgs
mechanism as the origin of electroweak symmetry breaking can be tested. The
couplings are accessible in multi-Higgs production processes at the LHC. In
this paper we investigate the prospects of measuring the trilinear Higgs
coupling in composite Higgs models. In these models, the Higgs boson emerges as
a pseudo-Goldstone boson of a strongly interacting sector, and the Higgs
potential is generated by loops of the Standard Model (SM) gauge bosons and
fermions. The Higgs self-couplings are modified compared to the SM and
controlled by the compositeness parameter $\xi$ in addition to the Higgs boson
mass. We construct areas of sensitivity to the trilinear Higgs coupling in the
relevant parameter space for various final states.
| [
{
"created": "Tue, 7 Dec 2010 17:38:26 GMT",
"version": "v1"
}
] | 2015-03-17 | [
[
"Grober",
"Ramona",
""
],
[
"Muhlleitner",
"Margarete",
""
]
] | The measurement of the trilinear and quartic Higgs self-couplings is necessary for the reconstruction of the Higgs potential. This way the Higgs mechanism as the origin of electroweak symmetry breaking can be tested. The couplings are accessible in multi-Higgs production processes at the LHC. In this paper we investigate the prospects of measuring the trilinear Higgs coupling in composite Higgs models. In these models, the Higgs boson emerges as a pseudo-Goldstone boson of a strongly interacting sector, and the Higgs potential is generated by loops of the Standard Model (SM) gauge bosons and fermions. The Higgs self-couplings are modified compared to the SM and controlled by the compositeness parameter $\xi$ in addition to the Higgs boson mass. We construct areas of sensitivity to the trilinear Higgs coupling in the relevant parameter space for various final states. |
hep-ph/0010277 | Peter John | Peter John | No Spontaneous CP Violation at Finite Temperature in the MSSM? | 5 pages, 1 figure. To appear in the Proceedings of Strong and
Electroweak Matter 2000 (SEWM2000), Marseilles | null | 10.1142/9789812799913_0035 | null | hep-ph | null | In order to generate the baryon asymmetry of the Universe sufficiently strong
CP violation is needed. It was therefore proposed that at finite temperature
there might be spontaneous (transitional) CP violation within the bubble walls
at the electroweak phase transition in supersymmetric models. We investigate
this question in the MSSM.
| [
{
"created": "Tue, 24 Oct 2000 15:56:51 GMT",
"version": "v1"
}
] | 2017-08-23 | [
[
"John",
"Peter",
""
]
] | In order to generate the baryon asymmetry of the Universe sufficiently strong CP violation is needed. It was therefore proposed that at finite temperature there might be spontaneous (transitional) CP violation within the bubble walls at the electroweak phase transition in supersymmetric models. We investigate this question in the MSSM. |
2312.17367 | York Schroder | Andrei I. Davydychev, Pablo Navarrete, York Schr\"oder | Factorizing two-loop vacuum sum-integrals | 20 pages, 2 figures | null | null | null | hep-ph hep-th | http://creativecommons.org/licenses/by/4.0/ | We derive analytic results for scalar massless bosonic vacuum sum-integrals
at two loops. Building upon a recent factorization proof of massive two-loop
vacuum integrals, we are able to solve the corresponding Matsubara sums and map
the result onto one-loop structures, thereby proving factorization also in the
sum-integral setting. Analytic results are provided for generic integer-valued
propagator- and numerator-powers of the class of sum-integrals under
consideration, allowing to eliminate them from any perturbative expansion,
dramatically simplifying the evaluation of some observables encountered e.g. in
hot QCD.
| [
{
"created": "Thu, 28 Dec 2023 21:24:07 GMT",
"version": "v1"
}
] | 2024-01-01 | [
[
"Davydychev",
"Andrei I.",
""
],
[
"Navarrete",
"Pablo",
""
],
[
"Schröder",
"York",
""
]
] | We derive analytic results for scalar massless bosonic vacuum sum-integrals at two loops. Building upon a recent factorization proof of massive two-loop vacuum integrals, we are able to solve the corresponding Matsubara sums and map the result onto one-loop structures, thereby proving factorization also in the sum-integral setting. Analytic results are provided for generic integer-valued propagator- and numerator-powers of the class of sum-integrals under consideration, allowing to eliminate them from any perturbative expansion, dramatically simplifying the evaluation of some observables encountered e.g. in hot QCD. |
hep-ph/0701181 | David London | Seungwon Baek and David London | Is There Still a B -> pi K Puzzle? | 4 pages, revtex, no figures. References changed; analysis and
conclusions unaltered | Phys.Lett.B653:249-253,2007 | 10.1016/j.physletb.2007.08.001 | UdeM-GPP-TH-07-156 | hep-ph | null | We perform a fit to the 2006 B -> pi K data and show that there is a
disagreement with the standard model. That is, the B -> pi K puzzle is still
present. In fact, it has gotten worse than in earlier years. Assuming that one
new-physics (NP) operator dominates, we show that a good fit is obtained only
when the electroweak penguin amplitude is modified. The NP amplitude must be
sizeable, with a large weak phase.
| [
{
"created": "Mon, 22 Jan 2007 14:27:01 GMT",
"version": "v1"
},
{
"created": "Thu, 25 Jan 2007 13:34:40 GMT",
"version": "v2"
}
] | 2008-11-26 | [
[
"Baek",
"Seungwon",
""
],
[
"London",
"David",
""
]
] | We perform a fit to the 2006 B -> pi K data and show that there is a disagreement with the standard model. That is, the B -> pi K puzzle is still present. In fact, it has gotten worse than in earlier years. Assuming that one new-physics (NP) operator dominates, we show that a good fit is obtained only when the electroweak penguin amplitude is modified. The NP amplitude must be sizeable, with a large weak phase. |
hep-ph/9902258 | Satoko Hino | S. Hino and S. Kumano (Saga University) | Structure functions in the polarized Drell-Yan processes with spin-1/2
and spin-1 hadrons: II. parton model | 27 pages, REVTeX, amsmath.sty, epsfig.sty, revtex.cls, 2 eps figures.
Phys. Rev. D in press. Complete postscript file is available at
http://www2.cc.saga-u.ac.jp/saga-u/riko/physics/quantum1/structure.html
Email: 97sm16@edu.cc.saga-u.ac.jp, kumanos@cc.saga-u.ac.jp | Phys.Rev. D60 (1999) 054018 | 10.1103/PhysRevD.60.054018 | SAGA-HE-139-98 | hep-ph hep-ex nucl-th | null | We analyze the polarized Drell-Yan processes with spin-1/2 and spin-1 hadrons
in a parton model. Quark and antiquark correlation functions are expressed in
terms of possible combinations of Lorentz vectors and pseudovectors with the
constrains of Hermiticity, parity conservation, and time-reversal invariance.
Then, we find tensor polarized distributions for a spin-1 hadron. The naive
parton model predicts that there exist 19 structure functions. However, there
are only four or five non-vanishing structure functions, depending on whether
the cross section is integrated over the virtual-photon transverse momentum
\vec Q_T or the limit Q_T->0 is taken. One of the finite structure functions is
related to the tensor polarized distribution b_1, and it does not exist in the
proton-proton reactions. The vanishing structure functions should be associated
with higher-twist physics. The tensor distributions can be measured by the
quadrupole polarization measurements. The Drell-Yan process has an advantage
over the lepton reaction in the sense that the antiquark tensor polarization
could be extracted rather easily.
| [
{
"created": "Sat, 6 Feb 1999 07:09:20 GMT",
"version": "v1"
},
{
"created": "Thu, 13 May 1999 03:35:25 GMT",
"version": "v2"
}
] | 2009-10-31 | [
[
"Hino",
"S.",
"",
"Saga University"
],
[
"Kumano",
"S.",
"",
"Saga University"
]
] | We analyze the polarized Drell-Yan processes with spin-1/2 and spin-1 hadrons in a parton model. Quark and antiquark correlation functions are expressed in terms of possible combinations of Lorentz vectors and pseudovectors with the constrains of Hermiticity, parity conservation, and time-reversal invariance. Then, we find tensor polarized distributions for a spin-1 hadron. The naive parton model predicts that there exist 19 structure functions. However, there are only four or five non-vanishing structure functions, depending on whether the cross section is integrated over the virtual-photon transverse momentum \vec Q_T or the limit Q_T->0 is taken. One of the finite structure functions is related to the tensor polarized distribution b_1, and it does not exist in the proton-proton reactions. The vanishing structure functions should be associated with higher-twist physics. The tensor distributions can be measured by the quadrupole polarization measurements. The Drell-Yan process has an advantage over the lepton reaction in the sense that the antiquark tensor polarization could be extracted rather easily. |
hep-ph/9802417 | Haim Goldberg | Haim Goldberg | Evidence for a Non-Zero Mass in the Dispersion Relation of Transverse
Photons in the Stellar Core | 11 pages, LaTeX, 1 figure using axodraw.sty | null | null | NUB-3172/98-Th | hep-ph | null | The electromagnetic two-body interaction energy is modified in the thermal
environment of the solar core. The modifications are shown to imply a gross
violation of standard solar physics unless the dispersion relation \omega_t(k)
for the transverse modes of the photon is altered to include a transverse mass.
A non-zero transverse mass $m_t^2\simeq e^2 n_e/m_e$ is, of course,
theoretically predicted to exist; the discussion in this paper implies that
such a mass is required in order to maintain the success of the standard solar
model. In that sense one may claim observational evidence for a non-trivial
dispersion relation for transverse photon frequencies in the solar core.
| [
{
"created": "Wed, 25 Feb 1998 15:38:45 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Goldberg",
"Haim",
""
]
] | The electromagnetic two-body interaction energy is modified in the thermal environment of the solar core. The modifications are shown to imply a gross violation of standard solar physics unless the dispersion relation \omega_t(k) for the transverse modes of the photon is altered to include a transverse mass. A non-zero transverse mass $m_t^2\simeq e^2 n_e/m_e$ is, of course, theoretically predicted to exist; the discussion in this paper implies that such a mass is required in order to maintain the success of the standard solar model. In that sense one may claim observational evidence for a non-trivial dispersion relation for transverse photon frequencies in the solar core. |
2105.09309 | Doojin Kim | P. S. Bhupal Dev, Doojin Kim, Kuver Sinha, Yongchao Zhang | New Interference Effects from Light Gauge Bosons in Neutrino-Electron
Scattering | 7 pages, 2 figures, 1 table, Journal version, Comments are welcome | Phys. Rev. D 104, 075001 (2021) | 10.1103/PhysRevD.104.075001 | MI-TH-2110 | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We point out that light gauge boson mediators could induce new interference
effects in neutrino-electron scattering that can be used to enhance the
sensitivity of neutrino-flavor-selective high-intensity neutrino experiments,
such as DUNE. We particularly emphasize a destructive interference effect,
leading to a deficit between the Standard Model expectation and the
experimental measurement of the differential cross-sections, which is prominent
only in either the neutrino or the antineutrino mode, depending on the mediator
couplings. Therefore, the individual neutrino (or antineutrino) mode could
allow for sensitivity reaches superior to the combined analysis, and moreover,
could distinguish between different types of gauge boson mediators.
| [
{
"created": "Wed, 19 May 2021 17:59:51 GMT",
"version": "v1"
},
{
"created": "Tue, 14 Sep 2021 21:27:49 GMT",
"version": "v2"
}
] | 2021-10-13 | [
[
"Dev",
"P. S. Bhupal",
""
],
[
"Kim",
"Doojin",
""
],
[
"Sinha",
"Kuver",
""
],
[
"Zhang",
"Yongchao",
""
]
] | We point out that light gauge boson mediators could induce new interference effects in neutrino-electron scattering that can be used to enhance the sensitivity of neutrino-flavor-selective high-intensity neutrino experiments, such as DUNE. We particularly emphasize a destructive interference effect, leading to a deficit between the Standard Model expectation and the experimental measurement of the differential cross-sections, which is prominent only in either the neutrino or the antineutrino mode, depending on the mediator couplings. Therefore, the individual neutrino (or antineutrino) mode could allow for sensitivity reaches superior to the combined analysis, and moreover, could distinguish between different types of gauge boson mediators. |
hep-ph/0310274 | Urs Wiedemann A. | A. Accardi, F. Arleo, N. Armesto, R. Baier, D. d'Enterria, R.J. Fries,
O. Kodololva, I.P. Lokhtin, A. Morsch, A. Nikitenko, S. Petrushanko, J.W.
Qiu, C. Roland, C.A. Salgado, L.I. Sarycheva, S.V. Shmatov, A.M. Snigirev, S.
Tapprogge, I. Vardanian, I. Vitev, R. Vogt, E. Wang, X.N. Wang, U.A.
Wiedemann, P.I. Zarubin, B. Zhang | Hard Probes in Heavy Ion Collisions at the LHC: Jet Physics | The writeup of the working group "Jet Physics" for the CERN Yellow
Report on "Hard Probes in Heavy Ion Collisions at the LHC", 123 pages.
Subgroup convenors: R. Baier, X.N. Wang, U.A. Wiedemann (theory) and I.P.
Lokhtin, A. Morsch (experiment). Editor: U.A. Wiedemann | null | null | null | hep-ph | null | We discuss the importance of high-pT hadron and jet measurements in
nucleus-nucleus collisions at the CERN Large Hadron Collider.
| [
{
"created": "Thu, 23 Oct 2003 13:04:14 GMT",
"version": "v1"
}
] | 2009-09-29 | [
[
"Accardi",
"A.",
""
],
[
"Arleo",
"F.",
""
],
[
"Armesto",
"N.",
""
],
[
"Baier",
"R.",
""
],
[
"d'Enterria",
"D.",
""
],
[
"Fries",
"R. J.",
""
],
[
"Kodololva",
"O.",
""
],
[
"Lokhtin",
"I. P.",
""
],
[
"Morsch",
"A.",
""
],
[
"Nikitenko",
"A.",
""
],
[
"Petrushanko",
"S.",
""
],
[
"Qiu",
"J. W.",
""
],
[
"Roland",
"C.",
""
],
[
"Salgado",
"C. A.",
""
],
[
"Sarycheva",
"L. I.",
""
],
[
"Shmatov",
"S. V.",
""
],
[
"Snigirev",
"A. M.",
""
],
[
"Tapprogge",
"S.",
""
],
[
"Vardanian",
"I.",
""
],
[
"Vitev",
"I.",
""
],
[
"Vogt",
"R.",
""
],
[
"Wang",
"E.",
""
],
[
"Wang",
"X. N.",
""
],
[
"Wiedemann",
"U. A.",
""
],
[
"Zarubin",
"P. I.",
""
],
[
"Zhang",
"B.",
""
]
] | We discuss the importance of high-pT hadron and jet measurements in nucleus-nucleus collisions at the CERN Large Hadron Collider. |
1506.06658 | Ernest Ma | Ernest Ma (UC Riverside & JCIAS, HKUST) | Radiative Mixing of the One Higgs Boson and Emergent Self-Interacting
Dark Matter | 10 pages, 4 figures | null | 10.1016/j.physletb.2016.01.033 | UCRHEP-T553 (June 2015) | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In all scalar extensions of the standard model of particle interactions, the
one Higgs boson responsible for electroweak symmetry breaking always mixes with
other neutral scalars at tree level unless a symmetry prevents it. An
unexplored important option is that the mixing may be radiative, and thus
guaranteed to be small. Two first such examples are discussed. One is based on
the soft breaking of the discrete symmetry $Z_3$. The other starts with the
non-Abelian discrete symmetry $A_4$ which is then softly broken to $Z_3$, and
results in the emergence of an interesting dark-matter candidate together with
a light mediator for the dark matter to have its own long-range interaction.
| [
{
"created": "Mon, 22 Jun 2015 15:46:33 GMT",
"version": "v1"
}
] | 2016-02-17 | [
[
"Ma",
"Ernest",
"",
"UC Riverside & JCIAS, HKUST"
]
] | In all scalar extensions of the standard model of particle interactions, the one Higgs boson responsible for electroweak symmetry breaking always mixes with other neutral scalars at tree level unless a symmetry prevents it. An unexplored important option is that the mixing may be radiative, and thus guaranteed to be small. Two first such examples are discussed. One is based on the soft breaking of the discrete symmetry $Z_3$. The other starts with the non-Abelian discrete symmetry $A_4$ which is then softly broken to $Z_3$, and results in the emergence of an interesting dark-matter candidate together with a light mediator for the dark matter to have its own long-range interaction. |
1111.5147 | Maik Stuke | Dominik J. Schwarz, Glenn D. Starkman, and Maik Stuke | First second of leptons | 4 pages, 2 figures; prepared for the 12th international conference on
Topics in Astroparticle and Underground Physics, TAUP2011. v2: matches
accepted version | null | 10.1088/1742-6596/375/1/032005 | BI-TP 2011/36 | hep-ph astro-ph.CO | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | A poorly constrained parameter in the Standard Model of Cosmology is the
lepton asymmetry l = \sum_f l_f=\sum_f(n_f+n_{\nu_f})/s. Each flavour asymmetry
l_f with f=e, \mu, {\tau} is the sum of the net particle density of the charged
leptons n_f and their corresponding neutrinos, normalized with the entropy
density s. Constraints on l_f \leq O(0.1) from BBN and CMB allow for lepton
flavour asymmetries orders of magnitudes larger then the baryon asymmetry b ~
10^{-10}. In this article we show how such large lepton (flavour) asymmetries
influence the early universe, in particular the freeze out of WIMPs and the
cosmic QCD transition.
| [
{
"created": "Tue, 22 Nov 2011 10:35:02 GMT",
"version": "v1"
},
{
"created": "Tue, 28 Feb 2012 07:46:29 GMT",
"version": "v2"
}
] | 2015-06-03 | [
[
"Schwarz",
"Dominik J.",
""
],
[
"Starkman",
"Glenn D.",
""
],
[
"Stuke",
"Maik",
""
]
] | A poorly constrained parameter in the Standard Model of Cosmology is the lepton asymmetry l = \sum_f l_f=\sum_f(n_f+n_{\nu_f})/s. Each flavour asymmetry l_f with f=e, \mu, {\tau} is the sum of the net particle density of the charged leptons n_f and their corresponding neutrinos, normalized with the entropy density s. Constraints on l_f \leq O(0.1) from BBN and CMB allow for lepton flavour asymmetries orders of magnitudes larger then the baryon asymmetry b ~ 10^{-10}. In this article we show how such large lepton (flavour) asymmetries influence the early universe, in particular the freeze out of WIMPs and the cosmic QCD transition. |
1010.0089 | Robert Fleischer | Kristof De Bruyn, Robert Fleischer, Patrick Koppenburg | Extracting gamma and Penguin Topologies through CP Violation in B_s^0 ->
J/psi K_S | 20 pages, 8 figures | Eur.Phys.J.C70:1025-1035,2010 | 10.1140/epjc/s10052-010-1495-z | Nikhef-2010-033 | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The B_s^0 -> J/psi K_S decay has recently been observed by the CDF
collaboration and will be of interest for the LHCb experiment. This channel
will offer a new tool to extract the angle gamma of the unitarity triangle and
to control doubly Cabibbo-suppressed penguin corrections to the determination
of sin(2beta) from the well-known B_d^0 -> J/psi K_S mode with the help of the
U-spin symmetry of strong interactions. While any competitive determination of
gamma is interesting, the latter aspect is particularly relevant as LHCb will
enter a territory of precision which makes the control of doubly
Cabibbo-suppressed Standard-Model corrections mandatory. Using the data from
CDF and the e^+e^- B factories as a guideline, we explore the sensitivity for
gamma and the penguin parameters and point out that the B_s^0-\bar B_s^0 mixing
phase phi_s, which is only about -2 deg in the Standard Model but may be
enhanced through new physics, is a key parameter for these analyses. We find
that the mixing-induced CP violation S(B_s^0 -> J/psi K_S) shows an interesting
correlation with sin(phi_s), which serves as a target region for the first
measurement of this observable at LHCb.
| [
{
"created": "Fri, 1 Oct 2010 08:00:59 GMT",
"version": "v1"
}
] | 2011-01-28 | [
[
"De Bruyn",
"Kristof",
""
],
[
"Fleischer",
"Robert",
""
],
[
"Koppenburg",
"Patrick",
""
]
] | The B_s^0 -> J/psi K_S decay has recently been observed by the CDF collaboration and will be of interest for the LHCb experiment. This channel will offer a new tool to extract the angle gamma of the unitarity triangle and to control doubly Cabibbo-suppressed penguin corrections to the determination of sin(2beta) from the well-known B_d^0 -> J/psi K_S mode with the help of the U-spin symmetry of strong interactions. While any competitive determination of gamma is interesting, the latter aspect is particularly relevant as LHCb will enter a territory of precision which makes the control of doubly Cabibbo-suppressed Standard-Model corrections mandatory. Using the data from CDF and the e^+e^- B factories as a guideline, we explore the sensitivity for gamma and the penguin parameters and point out that the B_s^0-\bar B_s^0 mixing phase phi_s, which is only about -2 deg in the Standard Model but may be enhanced through new physics, is a key parameter for these analyses. We find that the mixing-induced CP violation S(B_s^0 -> J/psi K_S) shows an interesting correlation with sin(phi_s), which serves as a target region for the first measurement of this observable at LHCb. |
hep-ph/0305290 | Tai-Fu Feng | Tai-Fu Feng, Tao Huang, Xue-Qian Li, Xin-Min Zhang, Shu-Min Zhao | Lepton Dipole Moments and Rare Decays in the CP-violating MSSM with
Nonuniversal Soft-Supersymmetry Breaking | Latex, 26 pages, 8 figures, accepted for publication in Phys. Rev. D | Phys.Rev. D68 (2003) 016004 | 10.1103/PhysRevD.68.016004 | null | hep-ph | null | We investigate the muon anomalous magnetic dipole moment (MDM), the muon
electric dipole moment (EDM) and the lepton-flavour-violating decays of the
$\tau-$lepton, $\tau \to \mu \gamma$ and $\tau\to 3\mu$, in the CP-violating
Minimal Supersymmetric Standard Model (MSSM) with nonuniversal
soft-supersymmetry breaking. We evaluate numerically the muon EDM and the
branching ratios $B(\tau \to \mu\gamma)$ and $B(\tau \to 3\mu)$, after taking
into account the experimental constraints from the electron EDM and muon MDM.
Upon imposition of the experimental limits on our theoretical predictions for
the aforementioned branching ratios and the muon MDM, we obtain an upper bound
of about $10^{-23} e\cdot cm$ on the muon EDM which lies well within the
explorable reach of the proposed experiment at BNL.
| [
{
"created": "Mon, 26 May 2003 10:37:49 GMT",
"version": "v1"
}
] | 2009-11-10 | [
[
"Feng",
"Tai-Fu",
""
],
[
"Huang",
"Tao",
""
],
[
"Li",
"Xue-Qian",
""
],
[
"Zhang",
"Xin-Min",
""
],
[
"Zhao",
"Shu-Min",
""
]
] | We investigate the muon anomalous magnetic dipole moment (MDM), the muon electric dipole moment (EDM) and the lepton-flavour-violating decays of the $\tau-$lepton, $\tau \to \mu \gamma$ and $\tau\to 3\mu$, in the CP-violating Minimal Supersymmetric Standard Model (MSSM) with nonuniversal soft-supersymmetry breaking. We evaluate numerically the muon EDM and the branching ratios $B(\tau \to \mu\gamma)$ and $B(\tau \to 3\mu)$, after taking into account the experimental constraints from the electron EDM and muon MDM. Upon imposition of the experimental limits on our theoretical predictions for the aforementioned branching ratios and the muon MDM, we obtain an upper bound of about $10^{-23} e\cdot cm$ on the muon EDM which lies well within the explorable reach of the proposed experiment at BNL. |
1101.0498 | Hiranmaya Mishra | Bhaswar Chatterjee, Hiranmaya Mishra, Amruta Mishra | Vacuum structure and chiral symmetry breaking in strong magnetic fields
for hot and dense quark matter | 24 pages with 12 figures. three new figures, discussions added;
version to appear in Phys Rev. D | Phys.Rev.D84:014016,2011 | 10.1103/PhysRevD.84.014016 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We investigate chiral symmetry breaking in strong magnetic fields at finite
temperature and densities in a 3 flavor Nambu Jona Lasinio (NJL) model
including the Kobayashi Maskawa t-Hooft (KMT) determinant term, using an
explicit structure for the ground state in terms of quark antiquark
condensates. The mass gap equations are solved self consistently and are used
to compute the thermodynamic potential. We also derive the equation of state
for strange quark matter in the presence of strong magnetic fields which could
be relevant for proto-neutron stars. ~
| [
{
"created": "Mon, 3 Jan 2011 11:45:19 GMT",
"version": "v1"
},
{
"created": "Mon, 30 May 2011 06:43:29 GMT",
"version": "v2"
}
] | 2011-08-08 | [
[
"Chatterjee",
"Bhaswar",
""
],
[
"Mishra",
"Hiranmaya",
""
],
[
"Mishra",
"Amruta",
""
]
] | We investigate chiral symmetry breaking in strong magnetic fields at finite temperature and densities in a 3 flavor Nambu Jona Lasinio (NJL) model including the Kobayashi Maskawa t-Hooft (KMT) determinant term, using an explicit structure for the ground state in terms of quark antiquark condensates. The mass gap equations are solved self consistently and are used to compute the thermodynamic potential. We also derive the equation of state for strange quark matter in the presence of strong magnetic fields which could be relevant for proto-neutron stars. ~ |
hep-ph/9711217 | null | Andrzej J. Buras (Technische Universitaet Muenchen, Physik Department) | CKM Matrix: Present and Future | Invited talk given at the Symposium on Heavy Flavours, Santa Barbara,
July 7-July 11, 1997, to appear in the proceedings. 33 pages, 5 PS and 1 EPS
figure (included), uses sprocl.sty (included) | null | null | TUM-HEP-299/97 | hep-ph | null | We review the present status of the CKM matrix and we offer some visions of
its future. After a brief presentation of the theoretical framework for weak
decays we discuss the following topics: i) CKM matrix from tree level decays,
ii) Standard analysis of the unitarity triangle, iii) CKM matrix from rare and
CP violating K- and B-decays, iv) CKM matrix from CP violation in two-body
B-decays. In particular we compare the CKM potentials of the standard analysis
of the unitarity triangle, of the very clean K --> \pi\nu\bar\nu decays and of
CP asymmetries in B-decays.
| [
{
"created": "Tue, 4 Nov 1997 00:13:19 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Buras",
"Andrzej J.",
"",
"Technische Universitaet Muenchen, Physik Department"
]
] | We review the present status of the CKM matrix and we offer some visions of its future. After a brief presentation of the theoretical framework for weak decays we discuss the following topics: i) CKM matrix from tree level decays, ii) Standard analysis of the unitarity triangle, iii) CKM matrix from rare and CP violating K- and B-decays, iv) CKM matrix from CP violation in two-body B-decays. In particular we compare the CKM potentials of the standard analysis of the unitarity triangle, of the very clean K --> \pi\nu\bar\nu decays and of CP asymmetries in B-decays. |
1202.3812 | Walter Tarantino | Walter Tarantino | Flavour Condensate and the Dark Sector of the Universe | PhD Thesis, King's College London, May 2011 | null | null | null | hep-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | This thesis is devoted to the development of a nonperturbative quantum field
theoretical approach to flavour physics, with special attention to cosmological
applications. Neutrino flavour oscillation is nowadays a fairly
well-established experimental fact. However, the formulation of flavour
oscillations in a relativistic field theoretical framework presents non-trivial
difficulties. A nonperturbative approach for building flavour states has been
proposed by Blasone, Vitiello and coworkers. The formalism implies a
non-trivial physical vacuum (called "flavour vacuum"), which might act as a
source of Dark Energy. Furthermore, such a vacuum has been recognized as the
effective vacuum state arising in the low energy limit of a string theoretical
model, D-particle Foam Model. In the attempt of probing the observable
phenomenology of the D-particle foam model, a simple toy model (two scalars
with mixing \`a la Blasone & Vitiello on a adiabatically expanding background)
has been studied, proving that the flavour vacuum might behave as Dark Energy
under certain assumptions. The first work presented in this thesis represents a
development of this approach. A more realistic model is considered, which
includes two flavoured Dirac fermions on a generic Friedmann-Robertson-Walker
universe. In this framework we show that the flavour vacuum presents different
features, which are incompatible with Dark Energy. Motivated by this
discrepancy, we next embark on the analysis of a simple supersymmetric model in
flat spacetime (free Wess-Zumino), proving that the bosonic component of
flavour vacuum acts as Dark Energy, whereas the fermionic as a source of Dark
Matter. Finally we develop a new method of calculation that open the way to a
nonperturbative extension of these results for interactive theories.
| [
{
"created": "Thu, 16 Feb 2012 22:48:30 GMT",
"version": "v1"
}
] | 2012-02-20 | [
[
"Tarantino",
"Walter",
""
]
] | This thesis is devoted to the development of a nonperturbative quantum field theoretical approach to flavour physics, with special attention to cosmological applications. Neutrino flavour oscillation is nowadays a fairly well-established experimental fact. However, the formulation of flavour oscillations in a relativistic field theoretical framework presents non-trivial difficulties. A nonperturbative approach for building flavour states has been proposed by Blasone, Vitiello and coworkers. The formalism implies a non-trivial physical vacuum (called "flavour vacuum"), which might act as a source of Dark Energy. Furthermore, such a vacuum has been recognized as the effective vacuum state arising in the low energy limit of a string theoretical model, D-particle Foam Model. In the attempt of probing the observable phenomenology of the D-particle foam model, a simple toy model (two scalars with mixing \`a la Blasone & Vitiello on a adiabatically expanding background) has been studied, proving that the flavour vacuum might behave as Dark Energy under certain assumptions. The first work presented in this thesis represents a development of this approach. A more realistic model is considered, which includes two flavoured Dirac fermions on a generic Friedmann-Robertson-Walker universe. In this framework we show that the flavour vacuum presents different features, which are incompatible with Dark Energy. Motivated by this discrepancy, we next embark on the analysis of a simple supersymmetric model in flat spacetime (free Wess-Zumino), proving that the bosonic component of flavour vacuum acts as Dark Energy, whereas the fermionic as a source of Dark Matter. Finally we develop a new method of calculation that open the way to a nonperturbative extension of these results for interactive theories. |
1511.05989 | Stephen Barr | S.M. Barr and Heng-Yu Chen | A Model of Quark and Lepton Mixing and Mass Hierarchy | 13 pages, 1 figure | Phys. Rev. D 93, 053009 (2016) | 10.1103/PhysRevD.93.053009 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | It is shown that an idea proposed in 1996 that relates in a qualitatively
correct way the inter-family mass hierarchies of the up quarks, down quarks,
charged leptons, and neutrinos, can be combined with a predictive scheme
recently proposed for relating quark mixing and neutrino mixing. In the
resulting model, the entire flavor structure of the quarks and leptons is
expressible in terms of two "master matrices": a diagonal matrix that gives the
inter-family mass ratios, and an off-diagonal matrix that controls all flavor
mixing.
| [
{
"created": "Wed, 18 Nov 2015 21:36:41 GMT",
"version": "v1"
}
] | 2016-03-23 | [
[
"Barr",
"S. M.",
""
],
[
"Chen",
"Heng-Yu",
""
]
] | It is shown that an idea proposed in 1996 that relates in a qualitatively correct way the inter-family mass hierarchies of the up quarks, down quarks, charged leptons, and neutrinos, can be combined with a predictive scheme recently proposed for relating quark mixing and neutrino mixing. In the resulting model, the entire flavor structure of the quarks and leptons is expressible in terms of two "master matrices": a diagonal matrix that gives the inter-family mass ratios, and an off-diagonal matrix that controls all flavor mixing. |
hep-ph/9502384 | G. T. Gabadadze | G.T. Gabadadze, A.L. Kataev | On Connection between Coefficient Functions for Deep-Inelastic and
Annihilation Processes | 5 p., LATEX file. | JETP Lett. 61 (1995) 448-452; Pisma Zh.Eksp.Teor.Fiz. 61 (1995)
439 | null | Preprint JINR E2-95-76 (1995), to be published in "Pisma JETP" v.
61, 1995. | hep-ph | null | It has been shown that the one-loop behavior of the axial anomaly, occurring
when the axial current is appropriately normalized, leads to the cancellation
of the corrections of type $C_F^N{\bar \alpha}_s^N,~~ (N\geq 1) $ in the
Crewther relation for the coefficient functions of deep-inelastic and
annihilation processes. The arguments in favour of the overall factorization of
the factor $\beta({\bar \alpha}_s)/ {\bar \alpha}_s$ in all orders of
perturbation theory in this relation are presented.
| [
{
"created": "Fri, 24 Feb 1995 12:48:25 GMT",
"version": "v1"
}
] | 2016-09-01 | [
[
"Gabadadze",
"G. T.",
""
],
[
"Kataev",
"A. L.",
""
]
] | It has been shown that the one-loop behavior of the axial anomaly, occurring when the axial current is appropriately normalized, leads to the cancellation of the corrections of type $C_F^N{\bar \alpha}_s^N,~~ (N\geq 1) $ in the Crewther relation for the coefficient functions of deep-inelastic and annihilation processes. The arguments in favour of the overall factorization of the factor $\beta({\bar \alpha}_s)/ {\bar \alpha}_s$ in all orders of perturbation theory in this relation are presented. |
1605.00061 | Pyungwon Ko | P. Ko | EW scale DM models with dark gauge symmetries | Proceeding for DSU2015, Corfu 2015, CosPA 2015 with similar titles.
arXiv admin note: text overlap with arXiv:1503.05412 | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this talk, I describe a class of electroweak (EW) scale dark matter (DM)
models where its stability or longevity are the results of underlying dark
gauge symmetries: stable due to unbroken local dark gauge symmetry or topology,
or long-lived due to the accidental global symmetry of dark gauge theories.
Compared with the usual phenomenological dark matter models (including DM EFT
or simplified DM models), DM models with local dark gauge symmetries include
dark gauge bosons, dark Higgs bosons and sometimes excited dark matter. And
dynamics among these fields are completely fixed by local gauge principle. The
idea of singlet portals including the Higgs portal can thermalize these hidden
sector dark matter very efficiently, so that these DM could be easily thermal
DM. I also discuss the limitation of the usual DM effective field theory or
simplified DM models without the full SM gauge symmetry, and emphasize the
importance of the full SM gauge symmetry and renormalizability especially for
collider searches for DM.
| [
{
"created": "Sat, 30 Apr 2016 04:17:45 GMT",
"version": "v1"
}
] | 2016-05-03 | [
[
"Ko",
"P.",
""
]
] | In this talk, I describe a class of electroweak (EW) scale dark matter (DM) models where its stability or longevity are the results of underlying dark gauge symmetries: stable due to unbroken local dark gauge symmetry or topology, or long-lived due to the accidental global symmetry of dark gauge theories. Compared with the usual phenomenological dark matter models (including DM EFT or simplified DM models), DM models with local dark gauge symmetries include dark gauge bosons, dark Higgs bosons and sometimes excited dark matter. And dynamics among these fields are completely fixed by local gauge principle. The idea of singlet portals including the Higgs portal can thermalize these hidden sector dark matter very efficiently, so that these DM could be easily thermal DM. I also discuss the limitation of the usual DM effective field theory or simplified DM models without the full SM gauge symmetry, and emphasize the importance of the full SM gauge symmetry and renormalizability especially for collider searches for DM. |
1902.00893 | Abhishek Iyer M | G. D'Ambrosio, A. M. Iyer, F. Piccinini and A.D. Polosa | Confronting $B$ anomalies with low energy parity violation | 8 pages, 7 Figures. Title modified, improved plots and discussion.
Added analysis with the inclusion of the muon. Added references and
acknowledgement. Matches version to appear in PRD | Phys. Rev. D 101, 035025 (2020) | 10.1103/PhysRevD.101.035025 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Indirect searches have the potential to probe scales beyond the realm of
direct searches. In this letter we consider the implications of two parity
violating experiments: weak charge of proton $Q_W^p$ and the Caesium atom
$Q_W^{Cs}$ on the solutions to lepton flavour non-universality violations
(LFUV) in the decay of $B$ mesons. Working in a generic implementation of a
minimal $Z^\prime$ model, we assume the primary contribution being due to the
electron to facilitate comparison with the low $q^2$ parity violating
experiments. We demonstrate that the conclusion is characterized by different
limiting behavior depending on the chirality of the lepton current. The
correlation developed in this study demonstrates the effectiveness in studying
the synergy between different experiments leading to a deeper understanding of
the interpretation of the existing data. It is shown that a possible future
improvement in the parity violating experiments can have far reaching
implications in the context of direct searches. We also comment on the prospect
of addition of the muon to the fits and the role it plays in ameliorating the
constraints on models of $Z'$. This offers a complimentary understanding of the
pattern of the coupling of the NP to the leptons, strongly suggesting either a
muon only or a combination of solutions to the anomalies.
| [
{
"created": "Sun, 3 Feb 2019 13:36:07 GMT",
"version": "v1"
},
{
"created": "Tue, 18 Feb 2020 11:02:07 GMT",
"version": "v2"
}
] | 2020-02-26 | [
[
"D'Ambrosio",
"G.",
""
],
[
"Iyer",
"A. M.",
""
],
[
"Piccinini",
"F.",
""
],
[
"Polosa",
"A. D.",
""
]
] | Indirect searches have the potential to probe scales beyond the realm of direct searches. In this letter we consider the implications of two parity violating experiments: weak charge of proton $Q_W^p$ and the Caesium atom $Q_W^{Cs}$ on the solutions to lepton flavour non-universality violations (LFUV) in the decay of $B$ mesons. Working in a generic implementation of a minimal $Z^\prime$ model, we assume the primary contribution being due to the electron to facilitate comparison with the low $q^2$ parity violating experiments. We demonstrate that the conclusion is characterized by different limiting behavior depending on the chirality of the lepton current. The correlation developed in this study demonstrates the effectiveness in studying the synergy between different experiments leading to a deeper understanding of the interpretation of the existing data. It is shown that a possible future improvement in the parity violating experiments can have far reaching implications in the context of direct searches. We also comment on the prospect of addition of the muon to the fits and the role it plays in ameliorating the constraints on models of $Z'$. This offers a complimentary understanding of the pattern of the coupling of the NP to the leptons, strongly suggesting either a muon only or a combination of solutions to the anomalies. |
0801.1901 | Thomas Walcher | Thomas Walcher | Hadron structure at small momentum transfer | 7 pages, 9 figures. Contribution to the International School of
Nuclear Physics, 29th Ccourse, "Quarks in Hadrons and Nuclei", Erice, Sicily,
16 - 24 September 2007 | Prog.Part.Nucl.Phys.61:106-112,2008 | 10.1016/j.ppnp.2007.12.027 | null | hep-ph | null | Giving three examples, the form factors of the nucleon, the polarisability of
the charged pion and the interference of the $S_{11}(1535)$ with the
$D_{13}(1520)$ excitation of the nucleon in the $\eta p$-decay channel, it is
argued that the hadron structure at low momentum transfer is highly significant
for studying QCD.
| [
{
"created": "Sat, 12 Jan 2008 13:15:49 GMT",
"version": "v1"
}
] | 2008-11-26 | [
[
"Walcher",
"Thomas",
""
]
] | Giving three examples, the form factors of the nucleon, the polarisability of the charged pion and the interference of the $S_{11}(1535)$ with the $D_{13}(1520)$ excitation of the nucleon in the $\eta p$-decay channel, it is argued that the hadron structure at low momentum transfer is highly significant for studying QCD. |
2301.05618 | Mat\v{e}j Vacul\v{c}iak | Matej Vaculciak, Jesus Guillermo Contreras, Jan Cepila | Role of rapidity choice for the impact-parameter dependent
Balitsky-Kovchegov equation | The contribution was presented at the Hot Quarks 2022 - Workshop for
young scientists on the physics of ultrarelativistic nucleus-nucleus
collisions, Dao House, Colorado, USA, October 11-17 2022 | null | null | null | hep-ph | http://creativecommons.org/licenses/by/4.0/ | Reaching higher energies of electron-ion collisions with facilities like EIC
is expected to provide a probe of a kinematic region where the parton densities
should start to exhibit signs of saturation. This phenomenon is theoretically
implemented by the Balitsky--Kovchegov (BK) equation, which, within the colour
dipole model, describes the evolution of the dipole scattering amplitude with
respect to rapidity. There are two possible formulations of the BK equation
based on which rapidity, projectile or target, is considered. Besides this
variable, there are four more degrees of freedom, two of which have been so far
incorporated into the numerical solutions. We present a comparative solution of
the two-dimensional BK equation formulated in both projectile and target
rapidity together with their impact on quantities to be observed at EIC such as
proton structure functions.
| [
{
"created": "Fri, 13 Jan 2023 15:38:06 GMT",
"version": "v1"
}
] | 2023-01-16 | [
[
"Vaculciak",
"Matej",
""
],
[
"Contreras",
"Jesus Guillermo",
""
],
[
"Cepila",
"Jan",
""
]
] | Reaching higher energies of electron-ion collisions with facilities like EIC is expected to provide a probe of a kinematic region where the parton densities should start to exhibit signs of saturation. This phenomenon is theoretically implemented by the Balitsky--Kovchegov (BK) equation, which, within the colour dipole model, describes the evolution of the dipole scattering amplitude with respect to rapidity. There are two possible formulations of the BK equation based on which rapidity, projectile or target, is considered. Besides this variable, there are four more degrees of freedom, two of which have been so far incorporated into the numerical solutions. We present a comparative solution of the two-dimensional BK equation formulated in both projectile and target rapidity together with their impact on quantities to be observed at EIC such as proton structure functions. |
hep-ph/0412414 | Benjamin Grinstein | Benjamin Grinstein | CKM Sides: Theory | Talk presented at FPCP04, submitted as proceedings; 10 pages, 4
figures | null | null | UCSD/PTH 04-23 | hep-ph | null | We review the theory of the determination of the CKM elements Vcb and Vub.
Particular attention is paid to the determination of Vcb through inclusive
semileptonic B decays to charm using a moment analysis, since this has shown
most progress recently. A precise method for the determination of Vub via
exclusive decays is described.
| [
{
"created": "Thu, 30 Dec 2004 01:54:48 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Grinstein",
"Benjamin",
""
]
] | We review the theory of the determination of the CKM elements Vcb and Vub. Particular attention is paid to the determination of Vcb through inclusive semileptonic B decays to charm using a moment analysis, since this has shown most progress recently. A precise method for the determination of Vub via exclusive decays is described. |
hep-ph/9401275 | null | Enrico Nardi | Neutrino Phenomenology from Unconventional E$_6$ models | Talk given at the ``International School on Cosmological Dark
Matter'' Valencia, Spain, October 4-8, 1993, Plain Tex, 8 pages + 2 figures
available upon request (nardi@umiphys.bitnet) | null | null | UM-TH 94-01 | hep-ph | null | Superstring derived $\E$ models can accommodate small neutrino masses if a
discrete symmetry is imposed which forbids tree level Dirac neutrino masses but
allows for radiative mass generation. The only possible symmetries of this kind
are known to be generation dependent. We explore the possibility that, as a
consequence of such a symmetry, the three sets of light states in each
generation do not have the same assignments with respect to the {\bf 27} of
$E_6$, implying that the gauge interactions under the additional $U(1)^\pr$
factors are non universal. Models realising such a scenario are found to be
viable, and by requiring the number of light neutral states to be minimal, an
almost unique pattern of neutrino masses and mixings arises. We briefly discuss
a model in which, with a natural choice of the parameters, $m_{\nu_\tau}\sim
0.1-10\,$eV is generated at one loop, $m_{\nu_\mu} \sim 10^{-3}\,$eV is
generated at two loops and ${\nu_e}$ remains massless.
| [
{
"created": "Mon, 17 Jan 1994 21:14:59 GMT",
"version": "v1"
}
] | 2009-09-25 | [
[
"Nardi",
"Enrico",
""
]
] | Superstring derived $\E$ models can accommodate small neutrino masses if a discrete symmetry is imposed which forbids tree level Dirac neutrino masses but allows for radiative mass generation. The only possible symmetries of this kind are known to be generation dependent. We explore the possibility that, as a consequence of such a symmetry, the three sets of light states in each generation do not have the same assignments with respect to the {\bf 27} of $E_6$, implying that the gauge interactions under the additional $U(1)^\pr$ factors are non universal. Models realising such a scenario are found to be viable, and by requiring the number of light neutral states to be minimal, an almost unique pattern of neutrino masses and mixings arises. We briefly discuss a model in which, with a natural choice of the parameters, $m_{\nu_\tau}\sim 0.1-10\,$eV is generated at one loop, $m_{\nu_\mu} \sim 10^{-3}\,$eV is generated at two loops and ${\nu_e}$ remains massless. |
1210.8265 | Singh N.Nimai | Chandan Duarah, Abhijeet Das and N. Nimai Singh | Dependence of $\tan^2 \theta_{12}$ on Dirac CP phase $\delta$ in
tri-bimaximal neutrino mixing under charged lepton correction | 8 pages, 4 figures | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We consider charged lepton correction to Tri-bimaximal(TBM) neutrino mixing,
defined by the relation $U_{PMNS}=U^{\dagger}_l U_{TB}$ and find possible form
of $U_l$ which can impart non-zero value of $\sin \theta_{13}$ as well as
$\tan^2 \theta_{23}<1$, consistent with latest global analysis data. We adopt a
new parametrization, other than the standard PDG parametrization, to introduce
Dirac CP violating phase $\delta$ in the PMNS matrix which is discussed by
Fritzsch. Under such charged lepton correction pattern we note that $\tan^2
\theta_{12}$ becomes dependent on the CP phase $\delta$ from where constraints
on $\delta$ phase can be obtained after employing experimental range of mixing
angles. To compute the values of mixing angles we assume the charged lepton
correction to be of Cabibbo-Kobayashi-Maskawa(CKM) like. Since all the mixing
matrices involved in the calculation, are derived from three dimensional
rotation matrices they satisfy unitarity condition.
| [
{
"created": "Wed, 31 Oct 2012 08:38:21 GMT",
"version": "v1"
}
] | 2012-11-01 | [
[
"Duarah",
"Chandan",
""
],
[
"Das",
"Abhijeet",
""
],
[
"Singh",
"N. Nimai",
""
]
] | We consider charged lepton correction to Tri-bimaximal(TBM) neutrino mixing, defined by the relation $U_{PMNS}=U^{\dagger}_l U_{TB}$ and find possible form of $U_l$ which can impart non-zero value of $\sin \theta_{13}$ as well as $\tan^2 \theta_{23}<1$, consistent with latest global analysis data. We adopt a new parametrization, other than the standard PDG parametrization, to introduce Dirac CP violating phase $\delta$ in the PMNS matrix which is discussed by Fritzsch. Under such charged lepton correction pattern we note that $\tan^2 \theta_{12}$ becomes dependent on the CP phase $\delta$ from where constraints on $\delta$ phase can be obtained after employing experimental range of mixing angles. To compute the values of mixing angles we assume the charged lepton correction to be of Cabibbo-Kobayashi-Maskawa(CKM) like. Since all the mixing matrices involved in the calculation, are derived from three dimensional rotation matrices they satisfy unitarity condition. |
1204.5925 | Florian Staub | H. K. Dreiner, K. Nickel, F. Staub, A. Vicente | New bounds on trilinear R-parity violation from lepton flavor violating
observables | 21 pages; 5 figures; v2: corrected bug, conclusion unchanged | Phys. Rev. D 86, 015003 (2012) | 10.1103/PhysRevD.86.015003 | BONN-TH-2012-07; LPT-12-37 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Many extensions of the leptonic sector of the Minimal Supersymmetric Standard
Model (MSSM) are known, most of them leading to observable flavor violating
effects. It has been recently shown that the 1-loop contributions to lepton
flavor violating three-body decays $l_i \to 3 l_j$ involving the $Z^0$ boson
may be dominant, that is, much more important than the usual photonic penguins.
Other processes like $\mu$-$e$ conversion in nuclei and flavor violating $\tau$
decays into mesons are also enhanced by the same effect. This is for instance
also the case in the MSSM with trilinear R-parity violation. The aim of this
work is to derive new bounds on the relevant combinations of R-parity violating
couplings and to compare them with previous results in the literature. For
heavy supersymmetric spectra the limits are improved by several orders of
magnitude. For completeness, also constraints coming from flavor violating
$Z^0$-decays and tree-level decay channels $l \to l_i l_j l_k$ are presented
for a set of benchmark points.
| [
{
"created": "Thu, 26 Apr 2012 13:56:51 GMT",
"version": "v1"
},
{
"created": "Sat, 9 Jun 2012 07:07:28 GMT",
"version": "v2"
}
] | 2012-07-09 | [
[
"Dreiner",
"H. K.",
""
],
[
"Nickel",
"K.",
""
],
[
"Staub",
"F.",
""
],
[
"Vicente",
"A.",
""
]
] | Many extensions of the leptonic sector of the Minimal Supersymmetric Standard Model (MSSM) are known, most of them leading to observable flavor violating effects. It has been recently shown that the 1-loop contributions to lepton flavor violating three-body decays $l_i \to 3 l_j$ involving the $Z^0$ boson may be dominant, that is, much more important than the usual photonic penguins. Other processes like $\mu$-$e$ conversion in nuclei and flavor violating $\tau$ decays into mesons are also enhanced by the same effect. This is for instance also the case in the MSSM with trilinear R-parity violation. The aim of this work is to derive new bounds on the relevant combinations of R-parity violating couplings and to compare them with previous results in the literature. For heavy supersymmetric spectra the limits are improved by several orders of magnitude. For completeness, also constraints coming from flavor violating $Z^0$-decays and tree-level decay channels $l \to l_i l_j l_k$ are presented for a set of benchmark points. |
2006.09425 | Graham Shore | Jamie I. McDonald and Graham M. Shore | Dynamical Evolution of Gravitational Leptogenesis | 59 pages, 19 figures. JHEP published version | null | 10.1007/JHEP10(2020)025 | null | hep-ph gr-qc hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Radiatively-induced gravitational leptogenesis is a potential mechanism to
explain the observed matter-antimatter asymmetry of the universe. Gravitational
tidal effects at the quantum loop level modify the dynamics of the leptons in
curved spacetime and may be encoded in a low-energy effective action Seff. It
has been shown in previous work how in a high-scale BSM theory the CP odd
curvature-induced interactions in Seff modify the dispersion relations of
leptons and antileptons differently in an expanding universe, giving rise to an
effective chemical potential and a non-vanishing equilibrium lepton-antilepton
asymmetry. In this paper, the CP even curvature interactions are shown to break
lepton number current conservation and modify the evolution of the lepton
number density as the universe expands. These effects are implemented in a
generalised Boltzmann equation and used to trace the dynamical evolution of the
lepton number density in different cosmological scenarios. The theory predicts
a potentially significant gravitationally-induced lepton-antilepton asymmetry
at very early times in the evolution of the universe.
| [
{
"created": "Tue, 16 Jun 2020 18:13:09 GMT",
"version": "v1"
},
{
"created": "Tue, 1 Sep 2020 15:13:52 GMT",
"version": "v2"
}
] | 2020-10-28 | [
[
"McDonald",
"Jamie I.",
""
],
[
"Shore",
"Graham M.",
""
]
] | Radiatively-induced gravitational leptogenesis is a potential mechanism to explain the observed matter-antimatter asymmetry of the universe. Gravitational tidal effects at the quantum loop level modify the dynamics of the leptons in curved spacetime and may be encoded in a low-energy effective action Seff. It has been shown in previous work how in a high-scale BSM theory the CP odd curvature-induced interactions in Seff modify the dispersion relations of leptons and antileptons differently in an expanding universe, giving rise to an effective chemical potential and a non-vanishing equilibrium lepton-antilepton asymmetry. In this paper, the CP even curvature interactions are shown to break lepton number current conservation and modify the evolution of the lepton number density as the universe expands. These effects are implemented in a generalised Boltzmann equation and used to trace the dynamical evolution of the lepton number density in different cosmological scenarios. The theory predicts a potentially significant gravitationally-induced lepton-antilepton asymmetry at very early times in the evolution of the universe. |
0907.3877 | Simone Morelli | Simone Morelli | Stueckelberg Axions and Anomalous Abelian Extensions of the Standard
Model | 218 pages, Ph.D. Thesis (Advisor: Claudio Coriano') | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | This thesis work analyzes basic field theoretical aspects of a class of
models motivated by orientifold vacua of string theory and some of their
phenomenological applications at the Large Hadron Collider. They extend the
gauge structure of the Standard Model by anomalous extra U(1) symmetries, which
involve Stuckelberg axions for anomaly cancellation and are accompanied by
Chern-Simons interactions. In particular, these effective actions are
characterized by a physical pseudoscalar (the axi-Higgs) in the CP-odd
spectrum, which has the properties of a generalized Peccei-Quinn axion, with
independent mass and couplings to the gauge fields. Amplitudes mediated by
anomalous gauge interactions are studied at the new collider in some specific
channels such as Drell-Yan and double prompt-photon and shown to be small.
Finally, we address the problem of the relation between the Green-Schwarz and
the Wess-Zumino mechanism(s) for anomaly cancellations in effective lagrangeans
involving anomalous gauge interactions, with their gauge symmetry restored
either with local or non-local counterterms and identify some unitarity bounds
in the Wess-Zumino case. These are due to the presence of anomaly poles in
scattering amplitudes mediated by the anomaly (BIM amplitudes) and whose
cancellation requires necessarly non-local counterterms. While the axi-Higgs
appears in the Wess-Zumino case, two axion-like particles are needed for the
cancellation of the gauge anomalies at all scales, one of them being a ghost.
| [
{
"created": "Wed, 22 Jul 2009 16:29:53 GMT",
"version": "v1"
}
] | 2009-07-23 | [
[
"Morelli",
"Simone",
""
]
] | This thesis work analyzes basic field theoretical aspects of a class of models motivated by orientifold vacua of string theory and some of their phenomenological applications at the Large Hadron Collider. They extend the gauge structure of the Standard Model by anomalous extra U(1) symmetries, which involve Stuckelberg axions for anomaly cancellation and are accompanied by Chern-Simons interactions. In particular, these effective actions are characterized by a physical pseudoscalar (the axi-Higgs) in the CP-odd spectrum, which has the properties of a generalized Peccei-Quinn axion, with independent mass and couplings to the gauge fields. Amplitudes mediated by anomalous gauge interactions are studied at the new collider in some specific channels such as Drell-Yan and double prompt-photon and shown to be small. Finally, we address the problem of the relation between the Green-Schwarz and the Wess-Zumino mechanism(s) for anomaly cancellations in effective lagrangeans involving anomalous gauge interactions, with their gauge symmetry restored either with local or non-local counterterms and identify some unitarity bounds in the Wess-Zumino case. These are due to the presence of anomaly poles in scattering amplitudes mediated by the anomaly (BIM amplitudes) and whose cancellation requires necessarly non-local counterterms. While the axi-Higgs appears in the Wess-Zumino case, two axion-like particles are needed for the cancellation of the gauge anomalies at all scales, one of them being a ghost. |
2406.03096 | Gerrit Bickendorf | Gerrit Bickendorf, Manuel Drees | Learning to see R-parity violating scalar top decays | 13 pages, 9 figures | null | null | null | hep-ph hep-ex | http://creativecommons.org/licenses/by/4.0/ | With this article we introduce recent, improved machine learning methods from
computer vision to the problem of event classification in particle physics.
Supersymmetric scalar top decays to top quarks and weak scale bino-like
neutralinos, where the neutralinos decay via the $UDD$ operator to three
quarks, are difficult to search for and therefore weakly constrained. The jet
substructure of the boosted decay products can be used to differentiate signal
from background events. We apply transformer-based computer vision models
CoAtNet and MaxViT to images built from jet constituents and compare the
classification performance to a more classical convolutional neural network
(CNN). We find that results from computer vision translate well onto physics
applications and both transformer-based models perform better than the CNN. By
replacing the CNN with MaxViT we find an improvement of $S/\sqrt{B}$ by a
factor of almost 2 for some neutralino masses. We show that combining this
classifier with additional features results in a strong separation of
background and signal. We also find that replacing a CNN with a MaxViT model in
a simple mock analysis can push the 95% C.L. exclusion limit of stop masses by
about $100$ GeV and $60$ GeV for neutralino masses of $100$ GeV and $500$ GeV.
| [
{
"created": "Wed, 5 Jun 2024 09:39:15 GMT",
"version": "v1"
}
] | 2024-06-07 | [
[
"Bickendorf",
"Gerrit",
""
],
[
"Drees",
"Manuel",
""
]
] | With this article we introduce recent, improved machine learning methods from computer vision to the problem of event classification in particle physics. Supersymmetric scalar top decays to top quarks and weak scale bino-like neutralinos, where the neutralinos decay via the $UDD$ operator to three quarks, are difficult to search for and therefore weakly constrained. The jet substructure of the boosted decay products can be used to differentiate signal from background events. We apply transformer-based computer vision models CoAtNet and MaxViT to images built from jet constituents and compare the classification performance to a more classical convolutional neural network (CNN). We find that results from computer vision translate well onto physics applications and both transformer-based models perform better than the CNN. By replacing the CNN with MaxViT we find an improvement of $S/\sqrt{B}$ by a factor of almost 2 for some neutralino masses. We show that combining this classifier with additional features results in a strong separation of background and signal. We also find that replacing a CNN with a MaxViT model in a simple mock analysis can push the 95% C.L. exclusion limit of stop masses by about $100$ GeV and $60$ GeV for neutralino masses of $100$ GeV and $500$ GeV. |
hep-ph/9510240 | 65247 | Tsung-Wen Yeh, Chien-er Lee | On the mass correction of heavy hadrons of arbitrary spin in heavy
hadron effective theory | 10 pages, revtex, no figures | null | null | NCKU-HEP-95-03 | hep-ph | null | The mass correction forms of the arbitrary spin heavy hadrons are derived by
using the projection operator method. The Bjorken sum rule for finite mass is
derived by using the results of here.
| [
{
"created": "Fri, 6 Oct 1995 17:00:33 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Yeh",
"Tsung-Wen",
""
],
[
"Lee",
"Chien-er",
""
]
] | The mass correction forms of the arbitrary spin heavy hadrons are derived by using the projection operator method. The Bjorken sum rule for finite mass is derived by using the results of here. |
2310.16967 | Francesco Giovanni Celiberto | Francesco Giovanni Celiberto, Luigi Delle Rose, Michael Fucilla,
Gabriele Gatto, Alessandro Papa | Towards high-energy Higgs+jet distributions at NLL matched to NLO | 6 pages, 1 figure, presented by F.G. Celiberto at the European
Physical Society Conference on High Energy Physics (EPS-HEP) 2023, 20-25
August 2023, Universit\"at Hamburg | null | null | null | hep-ph hep-ex | http://creativecommons.org/licenses/by/4.0/ | We report progress on the study of the inclusive semi-hard hadroproduction of
a Higgs+jet system at LHC and FCC collision energies. We describe a prototype
matching procedure aimed at combining NLO fixed-order computations via POWHEG,
with the NLL resummation of energy logarithms from JETHAD. We present
preliminary analyses on assessing the weight of systematic uncertainties, such
as the ones coming from finite top- and bottom-quark masses.
| [
{
"created": "Wed, 25 Oct 2023 20:07:28 GMT",
"version": "v1"
}
] | 2023-10-27 | [
[
"Celiberto",
"Francesco Giovanni",
""
],
[
"Rose",
"Luigi Delle",
""
],
[
"Fucilla",
"Michael",
""
],
[
"Gatto",
"Gabriele",
""
],
[
"Papa",
"Alessandro",
""
]
] | We report progress on the study of the inclusive semi-hard hadroproduction of a Higgs+jet system at LHC and FCC collision energies. We describe a prototype matching procedure aimed at combining NLO fixed-order computations via POWHEG, with the NLL resummation of energy logarithms from JETHAD. We present preliminary analyses on assessing the weight of systematic uncertainties, such as the ones coming from finite top- and bottom-quark masses. |
1909.05888 | Xabier Marcano | Xabier Marcano and Roberto A. Morales | Flavor techniques for LFV processes: Higgs decays in a general seesaw
model | 9 pages, 10 figures. Invited contribution to the research topic
"Lepton-Flavor-Violating Decays of the Higgs Boson" in Frontiers in Physics.
Extended numerical analysis and references. Matches published version | Front. in Phys. 7 (2020) 228 | 10.3389/fphy.2019.00228 | IFT-UAM/CSIC-19-110, FTUAM-19-17, LPT-Orsay-19-30 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Lepton flavor violating processes are optimal observables to test new
physics, since they are forbidden in the Standard Model while they may be
generated in new theories. The usual approach to these processes is to perform
the computations in the physical basis; nevertheless this may lose track of the
dependence on some of the fundamental parameters, in particular on those at the
origin of the flavor violation. Consequently, in order to obtain analytical
expressions directly in terms of these parameters, flavor techniques are often
preferred. In this work, we focus on the mass insertion approximation
technique, which works with the interaction states instead of the physical
ones, and provides diagrammatic expansions of the observables. After reviewing
the basics of this technique with two simple examples, we apply it to the
lepton flavor violating Higgs decays in the framework of a general type-I
seesaw model with an arbitrary number of right-handed neutrinos. We derive an
effective vertex valid to compute these observables when the right-handed
neutrino masses are above the electroweak scale and show that we recover
previous results obtained for low scale seesaws. Finally, we apply current
constraints on the model to conclude on maximum Higgs decay rates, which
unfortunately are far from current experimental sensitivities.
| [
{
"created": "Thu, 12 Sep 2019 18:06:35 GMT",
"version": "v1"
},
{
"created": "Mon, 17 Feb 2020 13:29:03 GMT",
"version": "v2"
}
] | 2020-02-18 | [
[
"Marcano",
"Xabier",
""
],
[
"Morales",
"Roberto A.",
""
]
] | Lepton flavor violating processes are optimal observables to test new physics, since they are forbidden in the Standard Model while they may be generated in new theories. The usual approach to these processes is to perform the computations in the physical basis; nevertheless this may lose track of the dependence on some of the fundamental parameters, in particular on those at the origin of the flavor violation. Consequently, in order to obtain analytical expressions directly in terms of these parameters, flavor techniques are often preferred. In this work, we focus on the mass insertion approximation technique, which works with the interaction states instead of the physical ones, and provides diagrammatic expansions of the observables. After reviewing the basics of this technique with two simple examples, we apply it to the lepton flavor violating Higgs decays in the framework of a general type-I seesaw model with an arbitrary number of right-handed neutrinos. We derive an effective vertex valid to compute these observables when the right-handed neutrino masses are above the electroweak scale and show that we recover previous results obtained for low scale seesaws. Finally, we apply current constraints on the model to conclude on maximum Higgs decay rates, which unfortunately are far from current experimental sensitivities. |
hep-ph/9405385 | Jihn E. Kim | Hang Bae Kim and Jihn E. Kim | Dark Matter and Structure Formation with Late Decaying Particles | Latex file, 21 pages plus 3 figures (3 postscript file) | Nucl.Phys.B433:421-434,1995 | 10.1016/0550-3213(94)00406-5 | null | hep-ph astro-ph | null | Since it became evident that the CDM model for cosmic structure formation
predicts smaller power on large scales than observed, many alternatives have
been suggested. Among them, the existence of late decaying particle can cure it
by delaying the beginning of the matter domination and increasing the horizon
length at that time. We discuss the realization of this scenario and present
the light neutrino and the light axino as possible examples of working particle
physics model. We point out that the increased power at sub-galaxy scale
predicted by this scenario could lead to rich sub-galaxy structures.
| [
{
"created": "Thu, 26 May 1994 09:39:20 GMT",
"version": "v1"
},
{
"created": "Fri, 27 May 1994 00:24:30 GMT",
"version": "v2"
}
] | 2010-12-09 | [
[
"Kim",
"Hang Bae",
""
],
[
"Kim",
"Jihn E.",
""
]
] | Since it became evident that the CDM model for cosmic structure formation predicts smaller power on large scales than observed, many alternatives have been suggested. Among them, the existence of late decaying particle can cure it by delaying the beginning of the matter domination and increasing the horizon length at that time. We discuss the realization of this scenario and present the light neutrino and the light axino as possible examples of working particle physics model. We point out that the increased power at sub-galaxy scale predicted by this scenario could lead to rich sub-galaxy structures. |
1104.1056 | Jose Bernabeu | J. Bernabeu | T and CPT Symmetries in Entangled Neutral Meson Systems | Proc. DISCRETE 2010, Symposium on Prospects in the Physics of
Discrete Symmetries, December 2010, Roma | null | 10.1088/1742-6596/335/1/012011 | IFIC/11-15 | hep-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Genuine tests of an asymmetry under T and/or CPT transformations imply the
interchange between in-states and out-states. I explain a methodology to
perform model-indepedent separate measurements of the three CP, T and CPT
symmetry violations for transitions involving the decay of the neutral meson
systems in B- and {\Phi}-factories. It makes use of the quantum-mechanical
entanglement only, for which the individual state of each neutral meson is not
defined before the decay of its orthogonal partner. The final proof of the
independence of the three asymmetries is that no other theoretical ingredient
is involved and that the event sample corresponding to each case is different
from the other two. The experimental analysis for the measurements of these
three asymmetries as function of the time interval {\Delta}t > 0 between the
first and second decays is discussed, as well as the significance of the
expected results. In particular, one may advance a first observation of true,
direct, evidence of Time-Reserval-Violation in B-factories by many standard
deviations from zero, without any reference to, and independent of,
CP-Violation. In some quantum gravity framework the CPT-transformation is
ill-defined, so there is a resulting loss of particle-antiparticle identity.
This mechanism induces a breaking of the EPR correlation in the entanglement
imposed by Bose statistics to the neutral meson system, the so-called
{\omega}-effect. I present results and prospects for the {\omega}-parameter in
the correlated neutral meson-antimeson states.
| [
{
"created": "Wed, 6 Apr 2011 11:02:22 GMT",
"version": "v1"
}
] | 2015-05-27 | [
[
"Bernabeu",
"J.",
""
]
] | Genuine tests of an asymmetry under T and/or CPT transformations imply the interchange between in-states and out-states. I explain a methodology to perform model-indepedent separate measurements of the three CP, T and CPT symmetry violations for transitions involving the decay of the neutral meson systems in B- and {\Phi}-factories. It makes use of the quantum-mechanical entanglement only, for which the individual state of each neutral meson is not defined before the decay of its orthogonal partner. The final proof of the independence of the three asymmetries is that no other theoretical ingredient is involved and that the event sample corresponding to each case is different from the other two. The experimental analysis for the measurements of these three asymmetries as function of the time interval {\Delta}t > 0 between the first and second decays is discussed, as well as the significance of the expected results. In particular, one may advance a first observation of true, direct, evidence of Time-Reserval-Violation in B-factories by many standard deviations from zero, without any reference to, and independent of, CP-Violation. In some quantum gravity framework the CPT-transformation is ill-defined, so there is a resulting loss of particle-antiparticle identity. This mechanism induces a breaking of the EPR correlation in the entanglement imposed by Bose statistics to the neutral meson system, the so-called {\omega}-effect. I present results and prospects for the {\omega}-parameter in the correlated neutral meson-antimeson states. |
1007.2256 | Roman Nikolaevich Lee | R.N. Lee | Calculating multiloop integrals using dimensional recurrence relation
and D-analyticity | Talk presented at 10th DESY Workshop on Elementary Particle Theory:
Loops and Legs in Quantum Field Theory, Worlitz, Germany, 25-30 April 2010 | Nucl.Phys.Proc.Suppl.205-206:135-140,2010 | 10.1016/j.nuclphysbps.2010.08.032 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We review the method of the calculation of multiloop integrals recently
suggested in Ref.[Lee2010]. A simple method of derivation of the dimensional
recurrence relation suitable for automatization is given. Some new analytic
results are given.
| [
{
"created": "Wed, 14 Jul 2010 05:08:47 GMT",
"version": "v1"
}
] | 2010-12-13 | [
[
"Lee",
"R. N.",
""
]
] | We review the method of the calculation of multiloop integrals recently suggested in Ref.[Lee2010]. A simple method of derivation of the dimensional recurrence relation suitable for automatization is given. Some new analytic results are given. |
hep-ph/0703042 | Lianyi He | Lianyi He and Pengfei Zhuang | Relativistic BCS-BEC Crossover at Zero Temperature | 8 pages, 3 figures. V2: typos corrected, a comment on mean field
theory added | Phys.Rev.D75:096003,2007 | 10.1103/PhysRevD.75.096003 | null | hep-ph cond-mat.supr-con hep-th nucl-th | null | We investigate the BCS-BEC crossover at zero temperature in the frame of a
relativistic model. The universality of the BCS-BEC crossover for
non-relativistic systems breaks down in relativistic case and the crossover can
be induced by changing the density. When the effective scattering length is
much less than the fermion Compton wavelength, we recover the non-relativistic
result if the gas is initially in non-relativistic state. At ultra-strong
coupling where the scattering length is of the order of the Compton wavelength,
a new BEC state appears. In this state the condensed bosons become nearly
massless and anti-fermions are excited. The behavior of the Goldstone mode and
the mixing between the amplitude and phase modes are significantly different in
different condensed regions.
| [
{
"created": "Mon, 5 Mar 2007 02:50:23 GMT",
"version": "v1"
},
{
"created": "Wed, 18 Apr 2007 08:18:45 GMT",
"version": "v2"
}
] | 2008-11-26 | [
[
"He",
"Lianyi",
""
],
[
"Zhuang",
"Pengfei",
""
]
] | We investigate the BCS-BEC crossover at zero temperature in the frame of a relativistic model. The universality of the BCS-BEC crossover for non-relativistic systems breaks down in relativistic case and the crossover can be induced by changing the density. When the effective scattering length is much less than the fermion Compton wavelength, we recover the non-relativistic result if the gas is initially in non-relativistic state. At ultra-strong coupling where the scattering length is of the order of the Compton wavelength, a new BEC state appears. In this state the condensed bosons become nearly massless and anti-fermions are excited. The behavior of the Goldstone mode and the mixing between the amplitude and phase modes are significantly different in different condensed regions. |
hep-ph/9808411 | Salvatore Mele | Salvatore Mele (CERN) | Experimental Constraints on the Cabibbo-Kobayashi-Maskawa Matrix | 10 pages, to be published in the proceedings of the Workshop on CP
Violation, Adelaide, Australia, July 3-8, 1998 | null | null | CERN-OPEN-98-022 | hep-ph | null | The LEP investigation of the Bd and Bs oscillations and of the
Cabibbo-Kobayashi-Maskawa matrix element Vub improve the constraints on the
other elements of this matrix.
From a fit to the experimental data and the theory calculations it is
possible to determine the vertex of the unitarity triangle as:
rho = 0.155 -0.105 +0.115 eta = 0.383 -0.060 +0.063.
The corresponding values of its angles, in their customary definition in
terms of sines for alpha and beta, are:
sin(2 alpha) = 0.08 -0.50 +0.43 sin(2 beta) = 0.75 +/- 0.10 gamma = 68 +/-
15o.
The fit also yields indirect information on the compatibility with zero of
the CP violating phase of the matrix, on some non-perturbative QCD parameters
and on the Bs oscillation frequency.
| [
{
"created": "Tue, 25 Aug 1998 13:00:23 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Mele",
"Salvatore",
"",
"CERN"
]
] | The LEP investigation of the Bd and Bs oscillations and of the Cabibbo-Kobayashi-Maskawa matrix element Vub improve the constraints on the other elements of this matrix. From a fit to the experimental data and the theory calculations it is possible to determine the vertex of the unitarity triangle as: rho = 0.155 -0.105 +0.115 eta = 0.383 -0.060 +0.063. The corresponding values of its angles, in their customary definition in terms of sines for alpha and beta, are: sin(2 alpha) = 0.08 -0.50 +0.43 sin(2 beta) = 0.75 +/- 0.10 gamma = 68 +/- 15o. The fit also yields indirect information on the compatibility with zero of the CP violating phase of the matrix, on some non-perturbative QCD parameters and on the Bs oscillation frequency. |
0708.0916 | Matthias Steinhauser | Marco Schreck, Matthias Steinhauser | Higgs Decay to Gluons at NNLO | 13 pages, minor corrections, references corrected and added, to be
published in Phys. Lett. B | Phys.Lett.B655:148-155,2007 | 10.1016/j.physletb.2007.08.080 | SFB/CPP-07-46, TTP07-20 | hep-ph | null | We present an analytical calculation of the next-to-next-to-leading order
corrections to the partial decay width $H\to gg$ for a Higgs boson in the
intermediate mass range. We apply an asymptotic expansion for $M_H\ll 2M_t$ and
compute three terms in the expansion. The leading term confirms the results
present in the literature. It is argued that our result is equivalent to an
exact calculation up to $M_H\approx M_t$. For a Higgs boson mass of 120 GeV the
power-suppressed terms lead to corrections of about 9% in the
next-to-next-to-leading order coefficient.
| [
{
"created": "Tue, 7 Aug 2007 10:05:30 GMT",
"version": "v1"
},
{
"created": "Thu, 13 Sep 2007 05:34:36 GMT",
"version": "v2"
}
] | 2008-11-26 | [
[
"Schreck",
"Marco",
""
],
[
"Steinhauser",
"Matthias",
""
]
] | We present an analytical calculation of the next-to-next-to-leading order corrections to the partial decay width $H\to gg$ for a Higgs boson in the intermediate mass range. We apply an asymptotic expansion for $M_H\ll 2M_t$ and compute three terms in the expansion. The leading term confirms the results present in the literature. It is argued that our result is equivalent to an exact calculation up to $M_H\approx M_t$. For a Higgs boson mass of 120 GeV the power-suppressed terms lead to corrections of about 9% in the next-to-next-to-leading order coefficient. |
hep-ph/0002128 | Gi-Chol Cho | Gi-Chol Cho (Scuola Normale Superiore, Pisa) | Looking for Z' bosons in Supersymmetric E_6 Models through Electroweak
Precision Data | 20 pages, 3 figures. submitted to the Brief Review section of
Mod.Phys.Lett.A | Mod.Phys.Lett.A15:311-332,2000 | 10.1016/S0217-7323(00)00030-X | SNS-PH/00-03 | hep-ph | null | We review constraints on additional Z' bosons predicted in supersymmetric
(SUSY) E_6 models from electroweak experiments - Z-pole experiments, mW
measurements and the low-energy neutral current (LENC) experiments. Four
representative models - \chi,\psi, \eta, \nu models - are studied in some
detail. We find that the improved data of parity violation in cesium atom,
which is 2.2-\sigma away from the Standard Model (SM) prediction, could be
explained by the exchange of the heavy mass eigenstate Z_2 in the intermediate
state. The improvement over the SM can be found in \chi, \eta, \nu models,
where the total \chi^2 of the fit to the 26 data points decreases by about five
units, owing to the better fit to the atomic parity violation. Impacts of the
kinetic mixing between the U(1)_Y and U(1)' gauge bosons on the \chi^2-analysis
are studied. We find that the Z' model with (\beta_E, \delta)=(-\pi/4,0.2),
where \beta_E is the mixing angle between Z_\chi and Z_\psi bosons and \delta
denotes the kinetic mixing, shows the most excellent fit to the data: the total
\chi^2 decreases by about seven units as compared to the SM. We introduce the
effective mixing parameter \zeta, a combination of the mass and the kinetic
mixing parameters. The 95% CL lower mass bound of Z_2 can be shown as a
function of \zeta. A theoretical prediction on \zeta and the U(1)'gauge
coupling g_E is studied for the \chi,\psi,\eta and \nu models by assuming the
minimal particle content of the SUSY E_6 models.
| [
{
"created": "Fri, 11 Feb 2000 15:12:52 GMT",
"version": "v1"
}
] | 2008-11-26 | [
[
"Cho",
"Gi-Chol",
"",
"Scuola Normale Superiore, Pisa"
]
] | We review constraints on additional Z' bosons predicted in supersymmetric (SUSY) E_6 models from electroweak experiments - Z-pole experiments, mW measurements and the low-energy neutral current (LENC) experiments. Four representative models - \chi,\psi, \eta, \nu models - are studied in some detail. We find that the improved data of parity violation in cesium atom, which is 2.2-\sigma away from the Standard Model (SM) prediction, could be explained by the exchange of the heavy mass eigenstate Z_2 in the intermediate state. The improvement over the SM can be found in \chi, \eta, \nu models, where the total \chi^2 of the fit to the 26 data points decreases by about five units, owing to the better fit to the atomic parity violation. Impacts of the kinetic mixing between the U(1)_Y and U(1)' gauge bosons on the \chi^2-analysis are studied. We find that the Z' model with (\beta_E, \delta)=(-\pi/4,0.2), where \beta_E is the mixing angle between Z_\chi and Z_\psi bosons and \delta denotes the kinetic mixing, shows the most excellent fit to the data: the total \chi^2 decreases by about seven units as compared to the SM. We introduce the effective mixing parameter \zeta, a combination of the mass and the kinetic mixing parameters. The 95% CL lower mass bound of Z_2 can be shown as a function of \zeta. A theoretical prediction on \zeta and the U(1)'gauge coupling g_E is studied for the \chi,\psi,\eta and \nu models by assuming the minimal particle content of the SUSY E_6 models. |
1407.1833 | Archana Anandakrishnan | Archana Anandakrishnan, Linda M. Carpenter, Stuart Raby | Degenerate gaugino mass region and mono-boson collider signatures | null | Phys. Rev. D 90, 055004 (2014) | 10.1103/PhysRevD.90.055004 | OHSTPY-HEP-T-14-004 | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this paper we discuss search strategies at the LHC for light electroweak
gauginos which are mostly Wino-like, Higgsino-like or an admixture. These
states are typically degenerate with decay products that are less energetic and
hence difficult to detect. In addition, their production cross-sections at a
hadron collider are suppressed compared to colored states such as the gluinos.
In order to detect these states one needs to trigger on initial or final state
radiation. Many previous analyses have focussed on mono-jet and mono-photon
triggers. In the paper we argue and show that these triggers are unlikely to
succeed, due to the large background from QCD backgrounds for the mono-jet
searches and the fact that the $p_T$ distribution of the mono-photons are
rapidly decreasing functions of $p_T$. We show this with both an analytic
calculation of photons in the initial state radiation and also a detailed
numerical analysis. We then argue that mono-Z triggers, from Z decaying into
charged leptons may well provide the best search strategy, in particular for
Higgsino-like and mixed cases.
| [
{
"created": "Mon, 7 Jul 2014 20:00:00 GMT",
"version": "v1"
}
] | 2014-09-10 | [
[
"Anandakrishnan",
"Archana",
""
],
[
"Carpenter",
"Linda M.",
""
],
[
"Raby",
"Stuart",
""
]
] | In this paper we discuss search strategies at the LHC for light electroweak gauginos which are mostly Wino-like, Higgsino-like or an admixture. These states are typically degenerate with decay products that are less energetic and hence difficult to detect. In addition, their production cross-sections at a hadron collider are suppressed compared to colored states such as the gluinos. In order to detect these states one needs to trigger on initial or final state radiation. Many previous analyses have focussed on mono-jet and mono-photon triggers. In the paper we argue and show that these triggers are unlikely to succeed, due to the large background from QCD backgrounds for the mono-jet searches and the fact that the $p_T$ distribution of the mono-photons are rapidly decreasing functions of $p_T$. We show this with both an analytic calculation of photons in the initial state radiation and also a detailed numerical analysis. We then argue that mono-Z triggers, from Z decaying into charged leptons may well provide the best search strategy, in particular for Higgsino-like and mixed cases. |
hep-ph/9712501 | Colin Froggatt | A.T. Davies, C.D. Froggatt and A. Usai | Spontaneous CP violation and Higgs spectrum in a Next to Minimal
Supersymmetric Model | 5 page LaTeX file; to appear in the Proceedings of the International
Europhysics Conference on High Energy Physics, Jerusalem, August 1997 | null | null | GUTPA/97/11/3 | hep-ph | null | We explore the possibility of spontaneous CP violation within the Next to
Minimal Supersymmetric Standard Model. In the most general form of the model,
without a discrete $Z_3$ symmetry, we find that even at tree level spontaneous
CP violation can occur, while also permitting Higgs masses consistent with
experiment.
| [
{
"created": "Tue, 23 Dec 1997 10:20:35 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Davies",
"A. T.",
""
],
[
"Froggatt",
"C. D.",
""
],
[
"Usai",
"A.",
""
]
] | We explore the possibility of spontaneous CP violation within the Next to Minimal Supersymmetric Standard Model. In the most general form of the model, without a discrete $Z_3$ symmetry, we find that even at tree level spontaneous CP violation can occur, while also permitting Higgs masses consistent with experiment. |
0709.1019 | Peihong Gu | Pei-Hong Gu, Hong-Jian He, Utpal Sarkar | Realistic Neutrinogenesis with Radiative Vertex Correction | 7 pages, 3 figures. Version accepted by PLB (minor rewording, refs
added) | Phys.Lett.B659:634-639,2008 | 10.1016/j.physletb.2007.11.061 | null | hep-ph | null | We propose a new model for naturally light Dirac neutrinos and explain the
baryon asymmetry of the universe through neutrinogenesis. We extend the
standard model with a real singlet scalar, a heavy singlet Dirac fermion and a
heavy doublet scalar besides three right-handed neutrinos, respecting lepton
number conservation and a Z_2 symmetry. The neutrinos acquire small Dirac
masses due to the suppression of the weak scale over the heavy mass scale. As a
key feature of our construction, once the heavy Dirac fermion and doublet
scalar go out of equilibrium, their decays induce the CP asymmetry from the
interference of tree-level processes with the \textit{radiative vertex
corrections} (rather than the self-energy corrections). Although there is no
lepton number violation, an equal and opposite amount of CP asymmetry is
generated in the left-handed and the right-handed neutrinos. The left-handed
lepton asymmetry would then be converted to the baryon asymmetry in the
presence of the sphalerons, while the right-handed lepton asymmetry remains
unaffected.
| [
{
"created": "Fri, 7 Sep 2007 08:28:21 GMT",
"version": "v1"
},
{
"created": "Wed, 14 Nov 2007 11:48:19 GMT",
"version": "v2"
}
] | 2008-11-26 | [
[
"Gu",
"Pei-Hong",
""
],
[
"He",
"Hong-Jian",
""
],
[
"Sarkar",
"Utpal",
""
]
] | We propose a new model for naturally light Dirac neutrinos and explain the baryon asymmetry of the universe through neutrinogenesis. We extend the standard model with a real singlet scalar, a heavy singlet Dirac fermion and a heavy doublet scalar besides three right-handed neutrinos, respecting lepton number conservation and a Z_2 symmetry. The neutrinos acquire small Dirac masses due to the suppression of the weak scale over the heavy mass scale. As a key feature of our construction, once the heavy Dirac fermion and doublet scalar go out of equilibrium, their decays induce the CP asymmetry from the interference of tree-level processes with the \textit{radiative vertex corrections} (rather than the self-energy corrections). Although there is no lepton number violation, an equal and opposite amount of CP asymmetry is generated in the left-handed and the right-handed neutrinos. The left-handed lepton asymmetry would then be converted to the baryon asymmetry in the presence of the sphalerons, while the right-handed lepton asymmetry remains unaffected. |
hep-ph/9504358 | Arnd Leike | Arnd Leike | SEMIANALYTIC DISTRIBUTIONS IN FOUR FERMION NEUTRAL CURRENT PROCESSES | 10 latex pages; typing errors in eqs. (A.9), (A.11) and (A.12) are
now corrected | null | null | LMU-11/95 | hep-ph | null | Analytical formulae for triple differential distributions ${\rm
d}^3\sigma/({\rm d}\cos\theta{\rm d}s_1{\rm d}s_2)$ in the neutral current
process $e^+e^-\rightarrow f_1\bar f_1 f_2\bar f_2$ are given. They allow to
obtain angular distributions, rapidity distributions and transversal momentum
distributions of one fermion pair by only two numerical integrations. Cuts can
be applied to the integration variables.
| [
{
"created": "Fri, 21 Apr 1995 10:12:11 GMT",
"version": "v1"
},
{
"created": "Fri, 12 May 1995 17:32:06 GMT",
"version": "v2"
}
] | 2008-02-03 | [
[
"Leike",
"Arnd",
""
]
] | Analytical formulae for triple differential distributions ${\rm d}^3\sigma/({\rm d}\cos\theta{\rm d}s_1{\rm d}s_2)$ in the neutral current process $e^+e^-\rightarrow f_1\bar f_1 f_2\bar f_2$ are given. They allow to obtain angular distributions, rapidity distributions and transversal momentum distributions of one fermion pair by only two numerical integrations. Cuts can be applied to the integration variables. |
1407.3082 | Dominik St\"ockinger | Christoph Gnendiger, Adrian Signer, Marcus Sperling, Dominik
St\"ockinger, Alexander Voigt | Two-loop results on the renormalization of vacuum expectation values and
infrared divergences in the FDH scheme | 8 pages, proceedings for Loops and Legs in Quantum Field Theory 2014,
Weimar, Germany | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Recent progress in the understanding of vacuum expectation values and of
infrared divergences in different regularization schemes is reviewed. Vacuum
expectation values are gauge and renormalization-scheme dependent quantities.
Using a method based on Slavnov-Taylor identities, the renormalization
properties could be better understood. The practical outcome is the computation
of the beta functions for vacuum expectation values in general gauge theories.
The infrared structure of gauge theory amplitudes depends on the regularization
scheme. The well-known prediction of the infrared structure in CDR can be
generalized to the FDH and DRED schemes and is in agreement with explicit
computations of the quark and gluon form factors. We discuss particularly the
correct renormalization procedure and the distinction between MSbar and DRbar
renormalization. An important practical outcome are transition rules between
CDR and FDH amplitudes.
| [
{
"created": "Fri, 11 Jul 2014 09:29:50 GMT",
"version": "v1"
}
] | 2014-07-14 | [
[
"Gnendiger",
"Christoph",
""
],
[
"Signer",
"Adrian",
""
],
[
"Sperling",
"Marcus",
""
],
[
"Stöckinger",
"Dominik",
""
],
[
"Voigt",
"Alexander",
""
]
] | Recent progress in the understanding of vacuum expectation values and of infrared divergences in different regularization schemes is reviewed. Vacuum expectation values are gauge and renormalization-scheme dependent quantities. Using a method based on Slavnov-Taylor identities, the renormalization properties could be better understood. The practical outcome is the computation of the beta functions for vacuum expectation values in general gauge theories. The infrared structure of gauge theory amplitudes depends on the regularization scheme. The well-known prediction of the infrared structure in CDR can be generalized to the FDH and DRED schemes and is in agreement with explicit computations of the quark and gluon form factors. We discuss particularly the correct renormalization procedure and the distinction between MSbar and DRbar renormalization. An important practical outcome are transition rules between CDR and FDH amplitudes. |
1012.5919 | Martin Jung | Martin Jung | Flavour Physics in two-Higgs-doublet models | 6 pages, 3 figures. Proceedings of CKM2010, the 6th International
Workshop on the CKM Unitarity Triangle, University of Warwick, UK, 6-10
September 2010 | null | null | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Despite the tremendous success of the Standard Model, the arguments for the
necessity of an extension are compelling. An attractive option is provided by
Two-Higgs-Doublet models, due to their simplicity and them being the low-energy
limit of some more complete theories. In the most general version of the model,
the fermionic couplings of the neutral scalars are non-diagonal in flavour and,
therefore, generate unwanted flavour-changing neutral-current phenomena.
Different ways to suppress FCNCs have been developed, giving rise to a variety
of specific implementations of the 2HDM. Three of these are discussed in this
talk, comparing their phenomenological influence in flavour observables: The
use of a discrete Z2-symmetry, an expansion around this limit in a minimal
flavour violation scenario assuming the decoupling limit, and the Aligned
Two-Higgs-Doublet Model. All of these result in the absence of tree-level
flavour-changing neutral currents. Their different phenomenological
consequences are demonstrated for a selection of observables, namely (semi-)
leptonic decays, B->X_s gamma and mixing in the B0_d,s-systems.
| [
{
"created": "Wed, 29 Dec 2010 12:10:35 GMT",
"version": "v1"
}
] | 2010-12-30 | [
[
"Jung",
"Martin",
""
]
] | Despite the tremendous success of the Standard Model, the arguments for the necessity of an extension are compelling. An attractive option is provided by Two-Higgs-Doublet models, due to their simplicity and them being the low-energy limit of some more complete theories. In the most general version of the model, the fermionic couplings of the neutral scalars are non-diagonal in flavour and, therefore, generate unwanted flavour-changing neutral-current phenomena. Different ways to suppress FCNCs have been developed, giving rise to a variety of specific implementations of the 2HDM. Three of these are discussed in this talk, comparing their phenomenological influence in flavour observables: The use of a discrete Z2-symmetry, an expansion around this limit in a minimal flavour violation scenario assuming the decoupling limit, and the Aligned Two-Higgs-Doublet Model. All of these result in the absence of tree-level flavour-changing neutral currents. Their different phenomenological consequences are demonstrated for a selection of observables, namely (semi-) leptonic decays, B->X_s gamma and mixing in the B0_d,s-systems. |
1611.09043 | Dieter Schildknecht | Dieter Schildknecht | On the Color Dipole Picture | 4 pages, 8 figures, AIP Conference Proceedings of Diffraction 2016,
Acireale (Catania, Sicily) September 2-8, 2016, ed. by A. Papa , to be
published | null | 10.1063/1.4977125 | null | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We give a brief representation of the theoretical results from the color
dipole picture, covering the total photoabsorption cross section, high-energy
$J/\psi$ photoproduction with respect to recent experimental data from the LHCb
Collaboration at CERN, and ultra-high energy neutrino scattering, relevant for
the ICE-CUBE experiment.
| [
{
"created": "Mon, 28 Nov 2016 10:07:39 GMT",
"version": "v1"
}
] | 2017-04-05 | [
[
"Schildknecht",
"Dieter",
""
]
] | We give a brief representation of the theoretical results from the color dipole picture, covering the total photoabsorption cross section, high-energy $J/\psi$ photoproduction with respect to recent experimental data from the LHCb Collaboration at CERN, and ultra-high energy neutrino scattering, relevant for the ICE-CUBE experiment. |
hep-ph/0409127 | Aaron Pierce | Alexander Maloney, Aaron Pierce, Jay G. Wacker (SLAC and Stanford) | D-Terms, Unification, and the Higgs Mass | 30+1 pages, 7 figures | JHEP 0606 (2006) 034 | 10.1088/1126-6708/2006/06/034 | SLAC-PUB-10701 | hep-ph hep-th | null | We study gauge extensions of the MSSM that contain non-decoupling D-terms,
which contribute to the Higgs boson mass. These models naturally maintain gauge
coupling unification and raise the Higgs mass without fine-tuning. Unification
constrains the structure of the gauge extensions, limiting the Higgs mass in
these models to roughly less than 150 GeV. The D-terms contribute to the Higgs
mass only if the extended gauge symmetry is broken at energies of a few TeV,
leading to new heavy gauge bosons in this mass range.
| [
{
"created": "Fri, 10 Sep 2004 21:30:15 GMT",
"version": "v1"
}
] | 2015-06-25 | [
[
"Maloney",
"Alexander",
"",
"SLAC and Stanford"
],
[
"Pierce",
"Aaron",
"",
"SLAC and Stanford"
],
[
"Wacker",
"Jay G.",
"",
"SLAC and Stanford"
]
] | We study gauge extensions of the MSSM that contain non-decoupling D-terms, which contribute to the Higgs boson mass. These models naturally maintain gauge coupling unification and raise the Higgs mass without fine-tuning. Unification constrains the structure of the gauge extensions, limiting the Higgs mass in these models to roughly less than 150 GeV. The D-terms contribute to the Higgs mass only if the extended gauge symmetry is broken at energies of a few TeV, leading to new heavy gauge bosons in this mass range. |
1907.13520 | Yuta Orikasa | Hiroshi Okada, Yuta Orikasa | A radiative seesaw model in modular $A_4$ symmetry | 13 pages, 3 figures, 2 tables. arXiv admin note: substantial text
overlap with arXiv:1907.04716 | null | null | APCTP Pre2019 - 018 | hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study one-loop induced radiative seesaw model applying a modular $A_4$
flavor symmetry, in which the neutrino mass matrix is achieved by two different
Yukawa couplings one of which also contributes to positive value of muon
anomalous magnetic moment as well as lepton flavor violations. Thanks to the
specific mass matrix via $A_4$ symmetry and its modular weight, we find several
predictions for lepton sector through our numerical analysis.
| [
{
"created": "Tue, 30 Jul 2019 08:41:31 GMT",
"version": "v1"
}
] | 2019-08-01 | [
[
"Okada",
"Hiroshi",
""
],
[
"Orikasa",
"Yuta",
""
]
] | We study one-loop induced radiative seesaw model applying a modular $A_4$ flavor symmetry, in which the neutrino mass matrix is achieved by two different Yukawa couplings one of which also contributes to positive value of muon anomalous magnetic moment as well as lepton flavor violations. Thanks to the specific mass matrix via $A_4$ symmetry and its modular weight, we find several predictions for lepton sector through our numerical analysis. |
1601.00652 | Norimi Yokozaki | Masaki Asano and Norimi Yokozaki | Light Higgsino as the tail of the $\mu$-$B_\mu$ solution | 14 pages, 4 figures, typo corrected, references added | Phys. Rev. D 93, 095002 (2016) | 10.1103/PhysRevD.93.095002 | null | hep-ph hep-ex | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Gauge mediation predicts 10 TeV or heavier squarks because such a heavy stop
is required to explain the observed 125 GeV Higgs boson mass without a large
trilinear soft mass term in the minimal supersymmetric standard model. Although
such a high scale cannot be searched by the LHC directly, gauge mediation also
predicts a hierarchy $\mu^2 \ll B_\mu$ by a simple and naive solution of the
$\mu$ problem. We point out that this simple and naive way of generating the
$\mu$ ($B_\mu$) term works in the case of 10 TeV or heavier squarks with a
slight breaking of a GUT relation among messenger B-terms (or supersymmetric
mass terms). Furthermore, the upper bound on the Higgsino mass is obtained from
the observed Higgs boson mass, perturbativity of a relevant coupling, and
conditions avoiding tachyonic sneutrinos and stop. It turns out that the light
Higgsino of O(100) GeV is a promising signal of gauge mediation.
| [
{
"created": "Mon, 4 Jan 2016 21:00:09 GMT",
"version": "v1"
},
{
"created": "Mon, 9 May 2016 10:03:20 GMT",
"version": "v2"
}
] | 2016-05-11 | [
[
"Asano",
"Masaki",
""
],
[
"Yokozaki",
"Norimi",
""
]
] | Gauge mediation predicts 10 TeV or heavier squarks because such a heavy stop is required to explain the observed 125 GeV Higgs boson mass without a large trilinear soft mass term in the minimal supersymmetric standard model. Although such a high scale cannot be searched by the LHC directly, gauge mediation also predicts a hierarchy $\mu^2 \ll B_\mu$ by a simple and naive solution of the $\mu$ problem. We point out that this simple and naive way of generating the $\mu$ ($B_\mu$) term works in the case of 10 TeV or heavier squarks with a slight breaking of a GUT relation among messenger B-terms (or supersymmetric mass terms). Furthermore, the upper bound on the Higgsino mass is obtained from the observed Higgs boson mass, perturbativity of a relevant coupling, and conditions avoiding tachyonic sneutrinos and stop. It turns out that the light Higgsino of O(100) GeV is a promising signal of gauge mediation. |
hep-ph/9705212 | null | G. Mangano and L. Rosa | Cosmological implications of a class of SO(10) models | latex file, 3 pages, appeared in Proceedings of TAUP 95, Toledo, 17
-21 September 1995. Nucl. Phys. B (Proc. Suppl.) 48 (1996) 272, Eds. A.
Morales, J. Morales and J. A. Villar | Nucl.Phys.Proc.Suppl. 48 (1996) 272 | 10.1016/0920-5632(96)00260-5 | null | hep-ph | null | The cosmological implications of a class of SO(10) models are discussed. In
particular we show how a good prediction for neutrino masses is obtained in
order to fit with the MSW mechanism to explain the solar neutrino flux deficit
and with the predicted amount of the dark matter hot component. A possible
scenario for baryogenesis is also considered.
| [
{
"created": "Fri, 2 May 1997 08:46:39 GMT",
"version": "v1"
}
] | 2009-10-30 | [
[
"Mangano",
"G.",
""
],
[
"Rosa",
"L.",
""
]
] | The cosmological implications of a class of SO(10) models are discussed. In particular we show how a good prediction for neutrino masses is obtained in order to fit with the MSW mechanism to explain the solar neutrino flux deficit and with the predicted amount of the dark matter hot component. A possible scenario for baryogenesis is also considered. |
0912.4510 | Qing-Hong Cao | Qing-Hong Cao, Ian Low, Gabe Shaughnessy | From Pamela to CDMS and Back | 4 pages, 4 figures. Version to appear in Phys. Lett. B | Phys.Lett.B691:73-76,2010 | 10.1016/j.physletb.2010.06.023 | null | hep-ph astro-ph.CO | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We take the recent result from the CDMS collaboration as a hint that the dark
matter has an elastic scattering cross section with the nucleon in the vicinity
of 10^-7 pb. By crossing symmetry such a cross section implies annihilation of
dark matter into hadrons inside the halo, resulting in an anti-proton flux that
could be constrained by data from the PAMELA collaboration if one includes a
large boost factor necessary to explain the PAMELA excess in the positron
fraction. As an illustration, we present a model-independent analysis for a
fermionic dark matter and study the upper bound on the boost factor using the
PAMELA anti-proton flux.
| [
{
"created": "Tue, 22 Dec 2009 20:52:07 GMT",
"version": "v1"
},
{
"created": "Wed, 23 Jun 2010 08:45:10 GMT",
"version": "v2"
}
] | 2014-11-20 | [
[
"Cao",
"Qing-Hong",
""
],
[
"Low",
"Ian",
""
],
[
"Shaughnessy",
"Gabe",
""
]
] | We take the recent result from the CDMS collaboration as a hint that the dark matter has an elastic scattering cross section with the nucleon in the vicinity of 10^-7 pb. By crossing symmetry such a cross section implies annihilation of dark matter into hadrons inside the halo, resulting in an anti-proton flux that could be constrained by data from the PAMELA collaboration if one includes a large boost factor necessary to explain the PAMELA excess in the positron fraction. As an illustration, we present a model-independent analysis for a fermionic dark matter and study the upper bound on the boost factor using the PAMELA anti-proton flux. |
0801.1592 | Bakmaev Sabir | E. Bartos, S. Bakmaev, E. A. Kuraev, M. G. Shatnev, M. Secansky | $2\gamma$ and $3\gamma$ annihilation as calibration processes for high
energy $e^+ e^-$ colliders | 9 pages, 1 figure | JETP Lett.87:73-77,2008 | 10.1007/s11448-008-2002-8 | null | hep-ph | null | Born differential cross sections and the lowest-order radiative correction to
them are obtained in the kinematics of large-angle final photons emission in
high-energy electron-positron annihilation processes. Taking into account
possible emission of real soft and hard photons in collinear kinematics we show
the validity of the Drell-Yan form of differential cross section with the
nonsinglet structure functions of initial leptons. The leading and next-to
leading contribution to the cross sections is obtained. The relevant numerical
estimations are presented.
| [
{
"created": "Thu, 10 Jan 2008 12:55:03 GMT",
"version": "v1"
}
] | 2009-04-30 | [
[
"Bartos",
"E.",
""
],
[
"Bakmaev",
"S.",
""
],
[
"Kuraev",
"E. A.",
""
],
[
"Shatnev",
"M. G.",
""
],
[
"Secansky",
"M.",
""
]
] | Born differential cross sections and the lowest-order radiative correction to them are obtained in the kinematics of large-angle final photons emission in high-energy electron-positron annihilation processes. Taking into account possible emission of real soft and hard photons in collinear kinematics we show the validity of the Drell-Yan form of differential cross section with the nonsinglet structure functions of initial leptons. The leading and next-to leading contribution to the cross sections is obtained. The relevant numerical estimations are presented. |
hep-ph/9703239 | Khalil Shaaban Said | Yoshiharu Kawamura, Shaaban Khalil and Tatsuo Kobayashi | Phenomenological implications of moduli-dominant SUSY breaking | Version to be appeared in Nucl. Phys. B | Nucl.Phys.B502:37-58,1997 | 10.1016/S0550-3213(97)00460-4 | null | hep-ph hep-th | null | We study moduli-dominated SUSY breaking within the framework of string
models. This type of SUSY breaking in general leads to non-universal soft
masses, i.e. soft scalar masses and gaugino masses. Further gauginos are
lighter than sfermions. This non-universality has phenomenologically important
implications. We investigate radiative electroweak symmetry breaking in the
mass spectrum derived from moduli-dominated SUSY breaking, where the lightest
chargino and neutralino are almost gauginos. Moreover, constraints from the
branching ratio of $b \to s \gamma$ and the relic abundance of the LSP are also
considered. The mass spectrum of moduli-dominated SUSY breaking is favorable to
the experimental bound of the $b \to s \gamma$ decay decreasing its branching
ratio. We obtain an upper bound for the gravitino mass from the cosmological
constraint.
| [
{
"created": "Wed, 5 Mar 1997 12:42:45 GMT",
"version": "v1"
},
{
"created": "Mon, 14 Jul 1997 14:13:40 GMT",
"version": "v2"
}
] | 2011-07-19 | [
[
"Kawamura",
"Yoshiharu",
""
],
[
"Khalil",
"Shaaban",
""
],
[
"Kobayashi",
"Tatsuo",
""
]
] | We study moduli-dominated SUSY breaking within the framework of string models. This type of SUSY breaking in general leads to non-universal soft masses, i.e. soft scalar masses and gaugino masses. Further gauginos are lighter than sfermions. This non-universality has phenomenologically important implications. We investigate radiative electroweak symmetry breaking in the mass spectrum derived from moduli-dominated SUSY breaking, where the lightest chargino and neutralino are almost gauginos. Moreover, constraints from the branching ratio of $b \to s \gamma$ and the relic abundance of the LSP are also considered. The mass spectrum of moduli-dominated SUSY breaking is favorable to the experimental bound of the $b \to s \gamma$ decay decreasing its branching ratio. We obtain an upper bound for the gravitino mass from the cosmological constraint. |
hep-ph/0003244 | Jan Nemcik | J. Nemchik | Anomalous t-dependence in diffractive electroproduction of 2S radially
excited light vector mesons at HERA | 15 pages and 2 figures | Eur.Phys.J.C18:711-718,2001 | 10.1007/s100520100572 | null | hep-ph | null | Within the color dipole gBFKL dynamics applied to the diffraction slope we
predict an anomalous t dependence of the differential cross section as a
function of energy and Q^2 for production of radially excited V'(2S) light
vector mesons in contradiction with a well known standard monotonous t-
behaviour for V(1S) mesons. The origin of this phenomenon is based on the
interplay of the nodal structure of V'(2S) radial wave function with the energy
and dipole size dependence of the color dipole cross section and of the
diffraction slope. We present how a different position of the node in V'(2S)
wave function leads to a different form of anomalous t- behaviour of the
differential cross section and discuss a possibility how to determine this
position from the low energy and HERA data.
| [
{
"created": "Fri, 24 Mar 2000 12:48:00 GMT",
"version": "v1"
}
] | 2009-01-07 | [
[
"Nemchik",
"J.",
""
]
] | Within the color dipole gBFKL dynamics applied to the diffraction slope we predict an anomalous t dependence of the differential cross section as a function of energy and Q^2 for production of radially excited V'(2S) light vector mesons in contradiction with a well known standard monotonous t- behaviour for V(1S) mesons. The origin of this phenomenon is based on the interplay of the nodal structure of V'(2S) radial wave function with the energy and dipole size dependence of the color dipole cross section and of the diffraction slope. We present how a different position of the node in V'(2S) wave function leads to a different form of anomalous t- behaviour of the differential cross section and discuss a possibility how to determine this position from the low energy and HERA data. |
hep-ph/0503146 | Marieke Postma | Rachel Jeannerot, Marieke Postma | Confronting hybrid inflation in supergravity with CMB data | 36 pages, 15 figures | JHEP0505:071,2005 | 10.1088/1126-6708/2005/05/071 | null | hep-ph astro-ph hep-th | null | $F$-term GUT inflation coupled to N=1 Supergravity is confronted with CMB
data. Corrections to the string mass-per-unit-length away from the Bogomolny
limit are taken into account. We find that a superpotential coupling
$10^{-7}/\mcN \lesssim \kappa \lesssim 10^{-2}/\mcN$, with $\mcN$ the dimension
of the Higgs-representation, is still compatible with the data. The parameter
space is enlarged in warm inflation, as well as in the curvaton and
inhomogeneous reheat scenario. $F$-strings formed at the end of $P$-term
inflation are also considered. Because these strings satisfy the Bogomolny
bound the bounds are stronger: the gauge coupling is constrained to the range
$10^{-7} < g <10^{-4}$.
| [
{
"created": "Tue, 15 Mar 2005 16:05:21 GMT",
"version": "v1"
}
] | 2009-11-11 | [
[
"Jeannerot",
"Rachel",
""
],
[
"Postma",
"Marieke",
""
]
] | $F$-term GUT inflation coupled to N=1 Supergravity is confronted with CMB data. Corrections to the string mass-per-unit-length away from the Bogomolny limit are taken into account. We find that a superpotential coupling $10^{-7}/\mcN \lesssim \kappa \lesssim 10^{-2}/\mcN$, with $\mcN$ the dimension of the Higgs-representation, is still compatible with the data. The parameter space is enlarged in warm inflation, as well as in the curvaton and inhomogeneous reheat scenario. $F$-strings formed at the end of $P$-term inflation are also considered. Because these strings satisfy the Bogomolny bound the bounds are stronger: the gauge coupling is constrained to the range $10^{-7} < g <10^{-4}$. |
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