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|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
hep-ph/0104028
|
Hans Volker Klapdor
|
H.V. Klapdor-Kleingrothaus (MPI-Kernphysik, Heidelberg, Germany)
|
New Underground Neutrino Observatory - GENIUS- in the New Millenium :
for Solar Neutrinos, Dark Matter and Double Beta Decay
|
16 pages, revtex, 8 figures,, Talk was presented at International
Workshop on Low Energy Solar Neutrinos (LowNu2), December 4 and 5, 2000,
Tokyo, Japan, to be published in World Scientific (2001) (eds) Y. Suzuki et
al., Conference Info -
http://www-sk.icrr.u-tokyo.ac.jp/neutlowe/2/transparency/index.html, Home
Page of Heidelberg Non-Accelerator Particle Physics Group:
http://www.mpi-hd.mpg.de/non_acc/
| null |
10.1142/9789812778000_0013
| null |
hep-ph
| null |
Double beta decay is indispensable to solve the question of the neutrino mass
matrix together with $\nu$ oscillation experiments. The most sensitive
experiment since eight years - the Heidelberg-Moscow experiment in Gran-Sasso -
already now, with the experimental limit of < m_\nu > < 0.26 eV excludes
degenerate $\nu$ mass scenarios allowing neutrinos as hot dark matter in the
universe for the small angle MSW solution of the solar neutrino problem. It
probes cosmological models including hot dark matter already now on the level
of future satellite experiments MAP and PLANCK. It further probes many topics
of beyond Standard Model physics at the TeV scale. Future experiments should
give access to the multi-TeV range and complement on many ways the search for
new physics at future colliders like LHC and NLC. For neutrino physics GENIUS
will allow to test almost all neutrino mass scenarios allowed by the present
neutrino oscillation experiments. At the same time GENIUS will cover a wide
range of the parameter space of predictions of SUSY for neutralinos as cold
dark matter. Further it has the potential to be a real-time detector for
low-energy (pp and 7Be) solar neutrinos. A GENIUS Test Facility has just been
funded and will come into operation by end of 2001.
|
[
{
"created": "Tue, 3 Apr 2001 11:11:05 GMT",
"version": "v1"
}
] |
2017-08-23
|
[
[
"Klapdor-Kleingrothaus",
"H. V.",
"",
"MPI-Kernphysik, Heidelberg, Germany"
]
] |
Double beta decay is indispensable to solve the question of the neutrino mass matrix together with $\nu$ oscillation experiments. The most sensitive experiment since eight years - the Heidelberg-Moscow experiment in Gran-Sasso - already now, with the experimental limit of < m_\nu > < 0.26 eV excludes degenerate $\nu$ mass scenarios allowing neutrinos as hot dark matter in the universe for the small angle MSW solution of the solar neutrino problem. It probes cosmological models including hot dark matter already now on the level of future satellite experiments MAP and PLANCK. It further probes many topics of beyond Standard Model physics at the TeV scale. Future experiments should give access to the multi-TeV range and complement on many ways the search for new physics at future colliders like LHC and NLC. For neutrino physics GENIUS will allow to test almost all neutrino mass scenarios allowed by the present neutrino oscillation experiments. At the same time GENIUS will cover a wide range of the parameter space of predictions of SUSY for neutralinos as cold dark matter. Further it has the potential to be a real-time detector for low-energy (pp and 7Be) solar neutrinos. A GENIUS Test Facility has just been funded and will come into operation by end of 2001.
|
hep-ph/0309085
|
Xiangdong Ji
|
Pervez Hoodbhoy, Xiangdong Ji, Feng Yuan
|
Probing Quark Distribution Amplitudes Through Generalized Parton
Distributions at Large Momentum Transfer
|
7 pages, 4 figures; new references and figure added, errors corrected
|
Phys.Rev.Lett. 92 (2004) 012003
|
10.1103/PhysRevLett.92.012003
|
DOE/ER/40762-292, UM-PP#04-001
|
hep-ph
| null |
In the large momentum transfer limit, generalized parton distributions can be
calculated through a QCD factorization theorem which involves
perturbatively-calculable hard kernels and light-cone parton distribution
amplitudes of hadrons. We illustrate this through the $H_q(x,\xi,t)$
distribution for the pion and proton, presenting the hard kernels at leading
order. As a result, experimental data on the generalized parton distributions
in this regime can be used to determine the functional form of the parton
distribution amplitudes which has thus far been quite challenging to obtain.
Our result can also be used as a constraint in phenomenological GPD
parametrizations.
|
[
{
"created": "Mon, 8 Sep 2003 21:59:19 GMT",
"version": "v1"
},
{
"created": "Wed, 17 Sep 2003 21:34:58 GMT",
"version": "v2"
}
] |
2009-11-10
|
[
[
"Hoodbhoy",
"Pervez",
""
],
[
"Ji",
"Xiangdong",
""
],
[
"Yuan",
"Feng",
""
]
] |
In the large momentum transfer limit, generalized parton distributions can be calculated through a QCD factorization theorem which involves perturbatively-calculable hard kernels and light-cone parton distribution amplitudes of hadrons. We illustrate this through the $H_q(x,\xi,t)$ distribution for the pion and proton, presenting the hard kernels at leading order. As a result, experimental data on the generalized parton distributions in this regime can be used to determine the functional form of the parton distribution amplitudes which has thus far been quite challenging to obtain. Our result can also be used as a constraint in phenomenological GPD parametrizations.
|
hep-ph/9409439
|
Kfti
|
Igor A. Bandos, Aleksey Yu. Nurmagambetov Dmitrij P. Sorokin and
Dmitrij V. Volkov
|
On another version of the twistor--like approach to superparticles
|
8 pages, LATEX
|
JETP Lett. 60 (1994) 621-626
| null | null |
hep-ph
| null |
Considered is a worldsheet supersymmetric generalization of the D=3
Ferber--Schirafuji twistor--superparticle action.
|
[
{
"created": "Thu, 29 Sep 1994 08:40:01 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Bandos",
"Igor A.",
""
],
[
"Sorokin",
"Aleksey Yu. Nurmagambetov Dmitrij P.",
""
],
[
"Volkov",
"Dmitrij V.",
""
]
] |
Considered is a worldsheet supersymmetric generalization of the D=3 Ferber--Schirafuji twistor--superparticle action.
|
hep-ph/0203131
|
George Lazarides
|
M.E. Gomez (IST, Lisbon), G. Lazarides (Aristotle University of
Thessaloniki), C. Pallis (SISSA)
|
Yukawa Quasi-Unification
|
27 pages including 10 figures, Revtex, minor corrections, version to
appear in Nucl. Phys. B
|
Nucl.Phys.B638:165-185,2002
|
10.1016/S0550-3213(02)00483-2
|
UT-STPD-1/02, FISIST/05-2002/CFIF
|
hep-ph
| null |
We construct concrete supersymmetric grand unified theories based on the
Pati-Salam gauge group SU(4)_c x SU(2)_L x SU(2)_R which naturally lead to a
moderate violation of "asymptotic" Yukawa unification and thus can allow an
acceptable b-quark mass even with universal boundary conditions. We consider
the constrained minimal supersymmetric standard model which emerges from one of
these theories with a deviation from Yukawa unification which is adequate for
mu>0. We show that this model possesses a wide and natural range of parameters
which is consistent with the data on b --> s gamma, the muon anomalous magnetic
moment, the cold dark matter abundance in the universe, and the Higgs boson
masses. The lightest supersymmetric particle can be as light as about 107 GeV.
|
[
{
"created": "Thu, 14 Mar 2002 12:45:06 GMT",
"version": "v1"
},
{
"created": "Wed, 12 Jun 2002 08:33:58 GMT",
"version": "v2"
},
{
"created": "Tue, 16 Jul 2002 16:04:23 GMT",
"version": "v3"
}
] |
2008-11-26
|
[
[
"Gomez",
"M. E.",
"",
"IST, Lisbon"
],
[
"Lazarides",
"G.",
"",
"Aristotle University of\n Thessaloniki"
],
[
"Pallis",
"C.",
"",
"SISSA"
]
] |
We construct concrete supersymmetric grand unified theories based on the Pati-Salam gauge group SU(4)_c x SU(2)_L x SU(2)_R which naturally lead to a moderate violation of "asymptotic" Yukawa unification and thus can allow an acceptable b-quark mass even with universal boundary conditions. We consider the constrained minimal supersymmetric standard model which emerges from one of these theories with a deviation from Yukawa unification which is adequate for mu>0. We show that this model possesses a wide and natural range of parameters which is consistent with the data on b --> s gamma, the muon anomalous magnetic moment, the cold dark matter abundance in the universe, and the Higgs boson masses. The lightest supersymmetric particle can be as light as about 107 GeV.
|
hep-ph/0004260
|
Nobuhiro Maekawa
|
Nobuhiro Maekawa
|
Vacuum selection by recollapsing
|
17 pages, no figure,argument on PBH formation is revised, typos are
corrected
| null | null |
KUNS-1660
|
hep-ph astro-ph
| null |
We discuss the possibility that the vacuum is dynamically determined in the
history of the universe. The point is that some of the bubbles with a certain
vacuum shrink by the evolution of the universe via gravity and may become black
holes. When the temperature of the phase transition T_{PT} is higher than 10^9
GeV, these black holes evaporate until now. If T_{PT}<10^9 GeV, we may see
these black holes in our universe. It is interesting that in many cases false
vacua are favored in the context of cosmology. By using this argument,
supersymmetry(SUSY), if it exists, can be broken cosmologically. We can guess
the SUSY breaking scale from the mass of the black holes.
|
[
{
"created": "Fri, 28 Apr 2000 01:45:32 GMT",
"version": "v1"
},
{
"created": "Wed, 19 Jul 2000 11:26:01 GMT",
"version": "v2"
}
] |
2007-05-23
|
[
[
"Maekawa",
"Nobuhiro",
""
]
] |
We discuss the possibility that the vacuum is dynamically determined in the history of the universe. The point is that some of the bubbles with a certain vacuum shrink by the evolution of the universe via gravity and may become black holes. When the temperature of the phase transition T_{PT} is higher than 10^9 GeV, these black holes evaporate until now. If T_{PT}<10^9 GeV, we may see these black holes in our universe. It is interesting that in many cases false vacua are favored in the context of cosmology. By using this argument, supersymmetry(SUSY), if it exists, can be broken cosmologically. We can guess the SUSY breaking scale from the mass of the black holes.
|
2202.01228
|
Ennio Salvioni
|
Gauthier Durieux, Matthew McCullough, Ennio Salvioni
|
Gegenbauer's Twin
|
7 pages, 2 figures; v2: minor changes and added Figure 1, matches
published version
|
JHEP 05 (2022) 140
|
10.1007/JHEP05(2022)140
|
CERN-TH-2022-012
|
hep-ph hep-ex
|
http://creativecommons.org/licenses/by/4.0/
|
In Twin Higgs models the dominant source of fine-tuning is the cancellation
of order $v^2/f^2$ required to obtain a Standard Model-like Higgs, where $v$
and $f$ are the electroweak and new physics scales, respectively. Recently
proposed Gegenbauer Goldstone models naturally realise $v^2/f^2 \ll 1$ and
hence remove this source of fine-tuning. By combining the two into
`Gegenbauer's Twin', we obtain a symmetry-based model for Higgs sector
naturalness consistent with current collider measurements without fine-tuning
of parameters. Single-Higgs coupling deviations of a few percent and trilinear
self-coupling deviations of order one are irreducible in the natural parameter
space. Thus, notably, the fingerprints of Gegenbauer's Twin could emerge first
through di-Higgs measurements at the High-Luminosity LHC.
|
[
{
"created": "Wed, 2 Feb 2022 19:00:01 GMT",
"version": "v1"
},
{
"created": "Tue, 24 May 2022 20:46:58 GMT",
"version": "v2"
}
] |
2022-05-26
|
[
[
"Durieux",
"Gauthier",
""
],
[
"McCullough",
"Matthew",
""
],
[
"Salvioni",
"Ennio",
""
]
] |
In Twin Higgs models the dominant source of fine-tuning is the cancellation of order $v^2/f^2$ required to obtain a Standard Model-like Higgs, where $v$ and $f$ are the electroweak and new physics scales, respectively. Recently proposed Gegenbauer Goldstone models naturally realise $v^2/f^2 \ll 1$ and hence remove this source of fine-tuning. By combining the two into `Gegenbauer's Twin', we obtain a symmetry-based model for Higgs sector naturalness consistent with current collider measurements without fine-tuning of parameters. Single-Higgs coupling deviations of a few percent and trilinear self-coupling deviations of order one are irreducible in the natural parameter space. Thus, notably, the fingerprints of Gegenbauer's Twin could emerge first through di-Higgs measurements at the High-Luminosity LHC.
|
1010.4131
|
Scientific Information Service Cern
|
P. Hernandez
|
Neutrino physics
|
49 pages, 47 figures, Lectures given at the 5th CERN-Latin-American
School of High-Energy Physics, Recinto Quirama, Colombia, 15 - 28 Mar 2009
|
CERN Yellow Report CERN-2010-001, pp. 229-278
| null |
CERN-2010-001-4
|
hep-ph
|
http://creativecommons.org/licenses/by/3.0/
|
The topics discussed in this lecture include: general properties of neutrinos
in the SM, the theory of neutrino masses and mixings (Dirac and Majorana),
neutrino oscillations both in vacuum and in matter, an overview of the
experimental evidence for neutrino masses and of the prospects in neutrino
oscillation physics. We also briefly review the relevance of neutrinos in
leptogenesis and in beyond-the-Standard-Model physics.
|
[
{
"created": "Wed, 20 Oct 2010 08:47:48 GMT",
"version": "v1"
}
] |
2010-10-21
|
[
[
"Hernandez",
"P.",
""
]
] |
The topics discussed in this lecture include: general properties of neutrinos in the SM, the theory of neutrino masses and mixings (Dirac and Majorana), neutrino oscillations both in vacuum and in matter, an overview of the experimental evidence for neutrino masses and of the prospects in neutrino oscillation physics. We also briefly review the relevance of neutrinos in leptogenesis and in beyond-the-Standard-Model physics.
|
1310.4380
|
Wayne W. Repko
|
Duane A. Dicus, Chung Kao and Wayne W. Repko
|
Comparison of $H\to\ell\bar{\ell}\gamma$ and $H\to\gamma\,Z,
Z\to\ell\bar{\ell}$ including the ATLAS cuts
|
4 pages, 3 figures, 2 tables
|
Phys. Rev. D 89, 033013 (2014)
|
10.1103/PhysRevD.89.033013
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
A precise comparison is made between the Dalitz decay
$H\to\ell\bar{\ell}\gamma$ and the two body decay $H\to\gamma
Z,Z\to\ell\bar{\ell}$ for electrons and for muons including experimental cuts
appropriate for the ATLAS detector. The widths for these two processes differ
by 8% for electrons and 3% for muons. Given that there remain QCD radiative
corrections of this order that are not included, this suggests that the
isolation of the Dalitz decay will be challenging.
|
[
{
"created": "Wed, 16 Oct 2013 13:57:54 GMT",
"version": "v1"
}
] |
2014-03-05
|
[
[
"Dicus",
"Duane A.",
""
],
[
"Kao",
"Chung",
""
],
[
"Repko",
"Wayne W.",
""
]
] |
A precise comparison is made between the Dalitz decay $H\to\ell\bar{\ell}\gamma$ and the two body decay $H\to\gamma Z,Z\to\ell\bar{\ell}$ for electrons and for muons including experimental cuts appropriate for the ATLAS detector. The widths for these two processes differ by 8% for electrons and 3% for muons. Given that there remain QCD radiative corrections of this order that are not included, this suggests that the isolation of the Dalitz decay will be challenging.
|
1808.09311
|
Tom\'a\v{s} Je\v{z}o
|
Tom\'a\v{s} Je\v{z}o
|
NLO matching for $t\bar{t}b\bar{b}$ production with massive $b$ quarks
|
Proceedings of XXVI International Workshop on Deep-Inelastic
Scattering and Related Subjects (DIS2018), 16-20 April 2018, Kobe, Japan
| null | null |
ZU-TH 34/18
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Measurements of $t\bar{t} H$ production in the $H\to b\bar{b}$ channel depend
in a critical way on the theoretical uncertainty associated with the
irreducible QCD $t\bar{t}+b$-jet background. We introduce a new $pp\to
t\bar{t}b\bar{b}$ POWHEG generator in the 4F scheme based on POWHEG-BOX-RES and
on OpenLoops for fast evaluation of the scattering amplitudes. We present
predictions and uncertainties for $t\bar{t}+b$-jet observables at the 13 TeV
LHC. We also consider theoretical uncertainties related to the POWHEG matching
method and to the parton shower (PS) modelling, with emphasis on $g\to
b\bar{b}$ splittings. In general, matching and shower uncertainties turn out to
be remarkably small. This is confirmed by a consistent comparison against
SHERPA+OpenLoops.
|
[
{
"created": "Tue, 28 Aug 2018 14:07:29 GMT",
"version": "v1"
}
] |
2018-08-29
|
[
[
"Ježo",
"Tomáš",
""
]
] |
Measurements of $t\bar{t} H$ production in the $H\to b\bar{b}$ channel depend in a critical way on the theoretical uncertainty associated with the irreducible QCD $t\bar{t}+b$-jet background. We introduce a new $pp\to t\bar{t}b\bar{b}$ POWHEG generator in the 4F scheme based on POWHEG-BOX-RES and on OpenLoops for fast evaluation of the scattering amplitudes. We present predictions and uncertainties for $t\bar{t}+b$-jet observables at the 13 TeV LHC. We also consider theoretical uncertainties related to the POWHEG matching method and to the parton shower (PS) modelling, with emphasis on $g\to b\bar{b}$ splittings. In general, matching and shower uncertainties turn out to be remarkably small. This is confirmed by a consistent comparison against SHERPA+OpenLoops.
|
hep-ph/9207226
| null |
Thomas Appelquist and George Triantaphyllou
|
Technicolor Enhancement of $t \bar{t}$ Production at TeV-Colliders
|
12 pages
|
Phys.Rev.Lett. 69 (1992) 2750-2753
|
10.1103/PhysRevLett.69.2750
|
YCTP-P26-92
|
hep-ph
| null |
It is shown that a technicolor theory containing a color-octet technipion,
usually denoted by $P^{0'}_{8}$, will give rise to an enhancement of $t \bar t$
production at the Tevatron, LHC and SSC, via the process $gg \rightarrow
P^{0'}_{8} \rightarrow t \bar t$. The relevant cross-sections are computed
taking into account the large lower bound on the top mass coming from the "top
search" experiments at LEP and CDF.
At the LHC and SSC, the signal is found to be comparable to the QCD
background, making the process quite accesible.
|
[
{
"created": "Thu, 9 Jul 1992 15:19:00 GMT",
"version": "v1"
}
] |
2009-10-22
|
[
[
"Appelquist",
"Thomas",
""
],
[
"Triantaphyllou",
"George",
""
]
] |
It is shown that a technicolor theory containing a color-octet technipion, usually denoted by $P^{0'}_{8}$, will give rise to an enhancement of $t \bar t$ production at the Tevatron, LHC and SSC, via the process $gg \rightarrow P^{0'}_{8} \rightarrow t \bar t$. The relevant cross-sections are computed taking into account the large lower bound on the top mass coming from the "top search" experiments at LEP and CDF. At the LHC and SSC, the signal is found to be comparable to the QCD background, making the process quite accesible.
|
hep-ph/0112293
|
Akaki Rusetsky
|
J. Gasser (Bern University), A. Rusetsky (Bern University and Tbilisi
University), J. Schacher (Bern University)
|
HadAtom01
|
30 pages, 5 postscript figures
| null | null |
Preprints BUTP-2001/23, BUHE-2001-07
|
hep-ph
| null |
These are the proceedings of the workshop "HadAtom01", held at the Institut
fuer Theoretische Physik, Universitaet Bern, October 11 - 12, 2001. The main
topics discussed at the workshop were the physics of hadronic atoms and in this
context recent results in experiment and theory. Included here are the list of
participants, the scientific program and a short contribution from each
speaker.
|
[
{
"created": "Fri, 21 Dec 2001 10:49:25 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Gasser",
"J.",
"",
"Bern University"
],
[
"Rusetsky",
"A.",
"",
"Bern University and Tbilisi\n University"
],
[
"Schacher",
"J.",
"",
"Bern University"
]
] |
These are the proceedings of the workshop "HadAtom01", held at the Institut fuer Theoretische Physik, Universitaet Bern, October 11 - 12, 2001. The main topics discussed at the workshop were the physics of hadronic atoms and in this context recent results in experiment and theory. Included here are the list of participants, the scientific program and a short contribution from each speaker.
|
hep-ph/9711436
|
Ruben A. Alanakyan
|
R.A. Alanakyan, V.H.Grabski
|
Single Charged and Neutral Supersymmetric Higgs Bosons Production with
Jet at pp Colliders
|
7 pages, LaTeX file, using eps.sty, 1 ps figures included
| null | null |
Preprint YerPHI 1496(13)-97
|
hep-ph
| null |
In the framework of Minimal Supersymmetric Standard Model Higgs bosons
production via gluino/squark loop in the processes $gu \to H^{+}d$, $gd \to
H^{-}u$,$gq \to H^{0}_iq$ are studied.
|
[
{
"created": "Mon, 24 Nov 1997 12:27:59 GMT",
"version": "v1"
}
] |
2019-08-17
|
[
[
"Alanakyan",
"R. A.",
""
],
[
"Grabski",
"V. H.",
""
]
] |
In the framework of Minimal Supersymmetric Standard Model Higgs bosons production via gluino/squark loop in the processes $gu \to H^{+}d$, $gd \to H^{-}u$,$gq \to H^{0}_iq$ are studied.
|
0811.2969
|
Are R. Raklev
|
N.-E. Bomark, S. Lola, P. Osland and A.R. Raklev
|
Gravitino Dark Matter and the Flavour Structure of R-violating Operators
|
20 pages, 7 figures; v2 also includes photons from three-body decays
in coupling limits, one additional author, matches version to appear in PLB
|
Phys.Lett.B677:62-70,2009
|
10.1016/j.physletb.2009.05.011
|
NORDITA-2008-51, CAVENDISH-HEP-2008-12, DAMTP-2008-88
|
hep-ph astro-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We study gravitino dark matter and slow gravitino decays within the framework
of R-violating supersymmetry, with particular emphasis on the flavour
dependence of the branching ratios and the allowed R-violating couplings. The
dominant decay modes and final state products turn out to be very sensitive to
the R-violating hierarchies. Mixing effects can be crucial in correctly
deriving the relative magnitude of the various contributions, particularly for
heavy flavours with phase space suppression. The study of the strength of
different decay rates for the gravitino is also correlated to collider
signatures expected from decays of the Next-to-Lightest Supersymmetric Particle
(NLSP) and to single superparticle production.
|
[
{
"created": "Tue, 18 Nov 2008 19:00:24 GMT",
"version": "v1"
},
{
"created": "Fri, 1 May 2009 17:29:34 GMT",
"version": "v2"
}
] |
2009-06-11
|
[
[
"Bomark",
"N. -E.",
""
],
[
"Lola",
"S.",
""
],
[
"Osland",
"P.",
""
],
[
"Raklev",
"A. R.",
""
]
] |
We study gravitino dark matter and slow gravitino decays within the framework of R-violating supersymmetry, with particular emphasis on the flavour dependence of the branching ratios and the allowed R-violating couplings. The dominant decay modes and final state products turn out to be very sensitive to the R-violating hierarchies. Mixing effects can be crucial in correctly deriving the relative magnitude of the various contributions, particularly for heavy flavours with phase space suppression. The study of the strength of different decay rates for the gravitino is also correlated to collider signatures expected from decays of the Next-to-Lightest Supersymmetric Particle (NLSP) and to single superparticle production.
|
hep-ph/0212373
|
Cai-Dian Lu
|
Cai-Dian Lu and Mao-Zhi Yang (IHEP, Beijing)
|
B to light meson transition form factors calculated in perturbative QCD
approach
|
21 pages, with 2 figures
|
Eur.Phys.J.C28:515-523,2003
|
10.1140/epjc/s2003-01199-y
|
BIHEP-TH-2002-62
|
hep-ph hep-ex
| null |
We calculate the $B\to P$, $B\to V$ (P: light pseudoscalar meson, V light
vector meson) form factors in the large-recoil limit in perturbative QCD
approach, including both the vector (axial vector) and tensor operators. In
general there are two leading components $\phi_B$ and $\bar{\phi}_B$ for $B$
meson wave functions. We consider both contributions of them. Sudakov effects
($k_{\perp}$ and threshold resummation) are included to regulate the soft
end-point singularity. By choosing the hard scale as the maximum virtualities
of internal particles in the hard $b$-quark decay amplitudes, Sudakov factors
can effectively suppress the long-distance soft contribution. Hard contribution
can be dominant in these approaches.
|
[
{
"created": "Thu, 26 Dec 2002 15:35:16 GMT",
"version": "v1"
},
{
"created": "Tue, 31 Dec 2002 04:26:09 GMT",
"version": "v2"
}
] |
2014-11-17
|
[
[
"Lu",
"Cai-Dian",
"",
"IHEP, Beijing"
],
[
"Yang",
"Mao-Zhi",
"",
"IHEP, Beijing"
]
] |
We calculate the $B\to P$, $B\to V$ (P: light pseudoscalar meson, V light vector meson) form factors in the large-recoil limit in perturbative QCD approach, including both the vector (axial vector) and tensor operators. In general there are two leading components $\phi_B$ and $\bar{\phi}_B$ for $B$ meson wave functions. We consider both contributions of them. Sudakov effects ($k_{\perp}$ and threshold resummation) are included to regulate the soft end-point singularity. By choosing the hard scale as the maximum virtualities of internal particles in the hard $b$-quark decay amplitudes, Sudakov factors can effectively suppress the long-distance soft contribution. Hard contribution can be dominant in these approaches.
|
2308.06812
|
Yang Li
|
Xianghui Cao, Yang Li, and James P. Vary
|
Forces inside a strongly-coupled scalar nucleon
|
30 pages, 21 figures
|
Phys. Rev. D 108, 056026 (2023)
|
10.1103/PhysRevD.108.056026
| null |
hep-ph hep-th nucl-th
|
http://creativecommons.org/licenses/by/4.0/
|
We investigate the gravitational form factors of a strongly coupled scalar
theory that mimic the interaction between the nucleon and the pion. The
non-perturbative calculation is based on the light-front Hamiltonian formalism.
We renormalize the energy-momentum tensor with a Fock sector dependent scheme.
We also systematically analyze the Lorentz structure of the energy-momentum
tensor and identify the suitable hadron matrix elements to extract the form
factors, avoiding the contamination of spurious contributions. We verify that
the extracted form factors obey momentum conservation as well as the mechanical
stability condition. From the gravitational form factors, we compute the energy
and pressure distributions of the system. Furthermore, we show that utilizing
the Hamiltonian eigenvalue equation, the off-diagonal Fock sector contributions
from the interaction term can be converted to diagonal Fock sector
contributions, yielding a systematic non-perturbative light-front wave function
representation of the energies and forces inside the system.
|
[
{
"created": "Sun, 13 Aug 2023 16:54:51 GMT",
"version": "v1"
},
{
"created": "Sat, 30 Sep 2023 12:14:36 GMT",
"version": "v2"
}
] |
2023-10-03
|
[
[
"Cao",
"Xianghui",
""
],
[
"Li",
"Yang",
""
],
[
"Vary",
"James P.",
""
]
] |
We investigate the gravitational form factors of a strongly coupled scalar theory that mimic the interaction between the nucleon and the pion. The non-perturbative calculation is based on the light-front Hamiltonian formalism. We renormalize the energy-momentum tensor with a Fock sector dependent scheme. We also systematically analyze the Lorentz structure of the energy-momentum tensor and identify the suitable hadron matrix elements to extract the form factors, avoiding the contamination of spurious contributions. We verify that the extracted form factors obey momentum conservation as well as the mechanical stability condition. From the gravitational form factors, we compute the energy and pressure distributions of the system. Furthermore, we show that utilizing the Hamiltonian eigenvalue equation, the off-diagonal Fock sector contributions from the interaction term can be converted to diagonal Fock sector contributions, yielding a systematic non-perturbative light-front wave function representation of the energies and forces inside the system.
|
hep-ph/0310080
|
Simon Hands
|
Simon Hands (University of Wales Swansea)
|
High Density Effective Theory Confronts the Fermi Liquid
|
15 pages, 2 figures; conclusion expanded, reference added
|
Phys.Rev. D69 (2004) 014020
|
10.1103/PhysRevD.69.014020
|
SWAT/03/382
|
hep-ph hep-lat nucl-th
| null |
The high density effective theory recently introduced by Hong and Hsu to
describe ultradense relativistic fermionic matter is used to calculate the
tree-level forward scattering amplitude between two particles at the Fermi
surface. While the direct term correctly reproduces that of the underlying
gauge theory, the exchange term has the wrong sign. The physical consequences
are discussed in the context of Landau's theoretical description of the Fermi
liquid.
|
[
{
"created": "Tue, 7 Oct 2003 08:55:00 GMT",
"version": "v1"
},
{
"created": "Thu, 20 Nov 2003 16:04:24 GMT",
"version": "v2"
}
] |
2009-11-10
|
[
[
"Hands",
"Simon",
"",
"University of Wales Swansea"
]
] |
The high density effective theory recently introduced by Hong and Hsu to describe ultradense relativistic fermionic matter is used to calculate the tree-level forward scattering amplitude between two particles at the Fermi surface. While the direct term correctly reproduces that of the underlying gauge theory, the exchange term has the wrong sign. The physical consequences are discussed in the context of Landau's theoretical description of the Fermi liquid.
|
hep-ph/0604042
|
Manuel Valverde
|
M. Valverde, J. E. Amaro and J. Nieves
|
Theoretical uncertainties on quasielastic charged-current
neutrino-nucleus cross sections
|
10 pages, 6 figures. Few errors corrected. Accepted in Physics
Letters B
|
Phys.Lett.B638:325-332,2006
|
10.1016/j.physletb.2006.05.053
| null |
hep-ph nucl-th
| null |
We estimate the theoretical uncertainties of the model developed in Phys.
Rev. C70 055503 for inclusive quasielastic charged-current neutrino-nucleus
reactions at intermediate energies. Besides we quantify the deviations of the
predictions of this many body framework from those obtained within a simple
Fermi gas model. An special attention has been paid to the ratio
\sigma(\mu)/\sigma(e) of interest for experiments on atmospheric neutrinos. We
show that uncertainties affecting this ratio are likely smaller than 5%
|
[
{
"created": "Wed, 5 Apr 2006 11:36:06 GMT",
"version": "v1"
},
{
"created": "Sat, 20 May 2006 14:54:56 GMT",
"version": "v2"
}
] |
2008-11-26
|
[
[
"Valverde",
"M.",
""
],
[
"Amaro",
"J. E.",
""
],
[
"Nieves",
"J.",
""
]
] |
We estimate the theoretical uncertainties of the model developed in Phys. Rev. C70 055503 for inclusive quasielastic charged-current neutrino-nucleus reactions at intermediate energies. Besides we quantify the deviations of the predictions of this many body framework from those obtained within a simple Fermi gas model. An special attention has been paid to the ratio \sigma(\mu)/\sigma(e) of interest for experiments on atmospheric neutrinos. We show that uncertainties affecting this ratio are likely smaller than 5%
|
hep-ph/9905227
|
Jeonghyeon Song
|
Kang Young Lee, H.S. Song, JeongHyeon Song and Chaehyun Yu (SNU)
|
Large Extra Dimension Effects on the Spin Configuration of the Top Quark
Pair at e^+ e^- Colliders
|
A discussion on the angular distribution is added with a table
|
Phys.Rev. D60 (1999) 093002
|
10.1103/PhysRevD.60.093002
|
SNUTP 99-022
|
hep-ph
| null |
Large extra dimension effects on the spin configuration of the top quark pair
at the $e^+ e^-\to t\bar{t}$ process are studied. It is shown that the TeV
scale quantum gravity effects cause significant deviations from the Standard
Model predictions for the spin configuration in the off-diagonal basis: they
lead to substantial cross sections of the like-spin states of the top quark
pair, which vanish in the SM; they weaken the pure dominance of the processes,
the Up-Down (Down-Up) spin states for the left-handed (right-handed) beam. In
addition it is shown that the angular cut $-0.5<\cos\theta<0$ is very effective
to determine the sign of the quantum gravity corrections.
|
[
{
"created": "Tue, 4 May 1999 07:58:26 GMT",
"version": "v1"
},
{
"created": "Fri, 7 May 1999 07:29:00 GMT",
"version": "v2"
}
] |
2009-10-31
|
[
[
"Lee",
"Kang Young",
"",
"SNU"
],
[
"Song",
"H. S.",
"",
"SNU"
],
[
"Song",
"JeongHyeon",
"",
"SNU"
],
[
"Yu",
"Chaehyun",
"",
"SNU"
]
] |
Large extra dimension effects on the spin configuration of the top quark pair at the $e^+ e^-\to t\bar{t}$ process are studied. It is shown that the TeV scale quantum gravity effects cause significant deviations from the Standard Model predictions for the spin configuration in the off-diagonal basis: they lead to substantial cross sections of the like-spin states of the top quark pair, which vanish in the SM; they weaken the pure dominance of the processes, the Up-Down (Down-Up) spin states for the left-handed (right-handed) beam. In addition it is shown that the angular cut $-0.5<\cos\theta<0$ is very effective to determine the sign of the quantum gravity corrections.
|
hep-ph/9605392
|
Vladimir Smirnov
|
J. Fleischer, V.A. Smirnov and O.V. Tarasov
|
Calculation of Feynman diagrams with zero mass threshold from their
small momentum expansion
|
17 pages with figures and tables, PostScript file gzip'ed and
uuencoded
|
Z.Phys. C74 (1997) 379-386
|
10.1016/S0920-5632(96)90039-0
|
BI-TP-9539
|
hep-ph hep-th
| null |
A method of calculating Feynman diagrams from their small momentum expansion
[1] is extended to diagrams with zero mass thresholds. We start from the
asymptotic expansion in large masses [2] (applied to the case when all $M_i^2$
are large compared to all momenta squared). Using dimensional regularization, a
finite result is obtained in terms of powers of logarithms (describing the
zero-threshold singularity) times power series in the momentum squared.
Surprisingly, these latter ones represent functions, which not only have the
expected physical `second threshold' but have a branchcut singularity as well
below threshold at a mirror position. These can be understood as
pseudothresholds corresponding to solutions of the Landau equations. In the
spacelike region the imaginary parts from the various contributions cancel. For
the two-loop examples with one mass $M$, in the timelike region for $q^2
\approx M^2$ we obtain approximations of high precision. This will be of
relevance in particular for the calculation of the decay $Z \to b\bar{b}$ in
the $m_b=0$ approximation.
|
[
{
"created": "Fri, 24 May 1996 23:27:33 GMT",
"version": "v1"
}
] |
2015-06-25
|
[
[
"Fleischer",
"J.",
""
],
[
"Smirnov",
"V. A.",
""
],
[
"Tarasov",
"O. V.",
""
]
] |
A method of calculating Feynman diagrams from their small momentum expansion [1] is extended to diagrams with zero mass thresholds. We start from the asymptotic expansion in large masses [2] (applied to the case when all $M_i^2$ are large compared to all momenta squared). Using dimensional regularization, a finite result is obtained in terms of powers of logarithms (describing the zero-threshold singularity) times power series in the momentum squared. Surprisingly, these latter ones represent functions, which not only have the expected physical `second threshold' but have a branchcut singularity as well below threshold at a mirror position. These can be understood as pseudothresholds corresponding to solutions of the Landau equations. In the spacelike region the imaginary parts from the various contributions cancel. For the two-loop examples with one mass $M$, in the timelike region for $q^2 \approx M^2$ we obtain approximations of high precision. This will be of relevance in particular for the calculation of the decay $Z \to b\bar{b}$ in the $m_b=0$ approximation.
|
1110.3729
|
Nikolaos Mavromatos
|
Nick E. Mavromatos
|
Neutrinos and the Universe
|
8 pages, latex, Invited talk at Nufact 11, CERN and U. of Geneva, 1-6
August 2011, submitted to IOP J. Conference Series
| null | null |
CERN-PH-TH/2011-252, KCL-PH-TH/2011-34, LCTS/2011-17
|
hep-ph gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
In this talk, I review the potential connection of neutrinos to the Physics
of the Early Universe, in particular the r\^ole of (sterile) neutrinos to
leptogenesis/baryogenesis and the dark sector of the Universe. The possibility
of CPT Violation among active neutrinos at early times and its role in
leptogenesis/baryogenesis without sterile neutrinos is also touched upon.
|
[
{
"created": "Mon, 17 Oct 2011 16:50:25 GMT",
"version": "v1"
}
] |
2011-10-24
|
[
[
"Mavromatos",
"Nick E.",
""
]
] |
In this talk, I review the potential connection of neutrinos to the Physics of the Early Universe, in particular the r\^ole of (sterile) neutrinos to leptogenesis/baryogenesis and the dark sector of the Universe. The possibility of CPT Violation among active neutrinos at early times and its role in leptogenesis/baryogenesis without sterile neutrinos is also touched upon.
|
hep-ph/0501039
|
Andre de Gouvea
|
Andre de Gouvea
|
See-Saw Energy Scale and the LSND Anomaly
|
revtex, 4 pages, no figures
|
Phys.Rev. D72 (2005) 033005
|
10.1103/PhysRevD.72.033005
|
NUHEP-TH/05-02
|
hep-ph
| null |
The most general, renormalizable Lagrangian that includes massive neutrinos
contains ``right-handed neutrino'' Majorana masses of order M. While there are
prejudices in favor of M much larger than the weak scale, virtually nothing is
known about the magnitude of M. I argue that the LSND anomaly provides,
currently, the only experimental hint: M around 1 eV. If this is the case, the
LSND mixing angles are functions of the active neutrino masses and mixing and,
remarkably, adequate fits to all data can be naturally obtained. I also discuss
consequences of this ``eV-seesaw'' for supernova neutrino oscillations, tritium
beta-decay, neutrinoless double-beta decay, and cosmology.
|
[
{
"created": "Fri, 7 Jan 2005 00:02:50 GMT",
"version": "v1"
}
] |
2009-11-11
|
[
[
"de Gouvea",
"Andre",
""
]
] |
The most general, renormalizable Lagrangian that includes massive neutrinos contains ``right-handed neutrino'' Majorana masses of order M. While there are prejudices in favor of M much larger than the weak scale, virtually nothing is known about the magnitude of M. I argue that the LSND anomaly provides, currently, the only experimental hint: M around 1 eV. If this is the case, the LSND mixing angles are functions of the active neutrino masses and mixing and, remarkably, adequate fits to all data can be naturally obtained. I also discuss consequences of this ``eV-seesaw'' for supernova neutrino oscillations, tritium beta-decay, neutrinoless double-beta decay, and cosmology.
|
1401.2364
|
Petr Zavada
|
Petr Zavada
|
Spin-orbital composition in relativistic many-fermion systems
|
5 pages, 2 tables. Presented at the Workshop DSPIN 2013, October
8-11, 2013, Dubna, Russia
| null | null | null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The interplay of spins and orbital angular moments of the fermions play an
important role for the structure of the many-fermion systems like atoms,
nuclei, nucleons (baryons) or mesons. We start our study from the one-fermion
eigenstates of angular momentum represented by the spinor spherical harmonics.
Afterwards we study the properties of many-fermion states resulting from a
multiple angular momentum composition of the one-fermion states, giving the
total angular momentum $J=\left\langle L\right\rangle+ \left\langle
S\right\rangle $, which is identified with the spin of the composite particle.
We demonstrate how the composition rules affect the relativistic interplay
between the sums of the spins $\left\langle S\right\rangle $ and orbital
angular moments $\left\langle L\right\rangle $ of the constituents, which
collectively generate the spin of composite particle. It is suggested that in a
relativistic case, when the masses of the constituent fermions are much less
than their energy (in the rest frame of the composite particle), then the spin
of the composite particle is dominated by the orbital angular moments
$\left\langle L\right\rangle $ of the constituents, while $\left\vert
\left\langle \mathbb{S}\right\rangle \right\vert \leq$ $J/3$. A special
attention is paid to the case $J=1/2$ that is related to the spin of proton
generated by the composition of spins and orbital angular moments of the
quarks.
|
[
{
"created": "Fri, 10 Jan 2014 15:07:46 GMT",
"version": "v1"
}
] |
2014-01-13
|
[
[
"Zavada",
"Petr",
""
]
] |
The interplay of spins and orbital angular moments of the fermions play an important role for the structure of the many-fermion systems like atoms, nuclei, nucleons (baryons) or mesons. We start our study from the one-fermion eigenstates of angular momentum represented by the spinor spherical harmonics. Afterwards we study the properties of many-fermion states resulting from a multiple angular momentum composition of the one-fermion states, giving the total angular momentum $J=\left\langle L\right\rangle+ \left\langle S\right\rangle $, which is identified with the spin of the composite particle. We demonstrate how the composition rules affect the relativistic interplay between the sums of the spins $\left\langle S\right\rangle $ and orbital angular moments $\left\langle L\right\rangle $ of the constituents, which collectively generate the spin of composite particle. It is suggested that in a relativistic case, when the masses of the constituent fermions are much less than their energy (in the rest frame of the composite particle), then the spin of the composite particle is dominated by the orbital angular moments $\left\langle L\right\rangle $ of the constituents, while $\left\vert \left\langle \mathbb{S}\right\rangle \right\vert \leq$ $J/3$. A special attention is paid to the case $J=1/2$ that is related to the spin of proton generated by the composition of spins and orbital angular moments of the quarks.
|
0705.2275
|
Yoshio Koide
|
Yoshio Koide
|
S_4 Flavor Symmetry Embedded into SU(3) and Lepton Masses and Mixing
|
12 pages, no figure, to appear on JHEP
|
JHEP 0708:086,2007
|
10.1088/1126-6708/2007/08/086
| null |
hep-ph
| null |
Based on an assumption that an S_4 flavor symmetry is embedded into SU(3), a
lepton mass matrix model is investigated. A Frogatt-Nielsen type model is
assumed, and the flavor structures of the masses and mixing are caused by VEVs
of SU(2)_L-singlet scalars \phi_u and \phi_d which are nonets (8+1) of the
SU(3) flavor symmetry, and which are broken into 2+3+3' and 1 of S_4. If we
require the invariance under the transformation (\phi^{(8)},\phi^{(1)}) \to
(-\phi^{(8)},+\phi^{(1)}) for the superpotential of the nonet field
\phi^{(8+1)}, the model leads to a beautiful relation for the charged lepton
masses. The observed tribimaximal neutrino mixing is understood by assuming two
SU(3) singlet right-handed neutrinos \nu_R^{(\pm)} and an SU(3) triplet scalar
\chi.
|
[
{
"created": "Wed, 16 May 2007 03:16:43 GMT",
"version": "v1"
},
{
"created": "Thu, 24 May 2007 08:23:30 GMT",
"version": "v2"
},
{
"created": "Wed, 27 Jun 2007 02:55:01 GMT",
"version": "v3"
},
{
"created": "Mon, 20 Aug 2007 05:29:52 GMT",
"version": "v4"
}
] |
2009-01-06
|
[
[
"Koide",
"Yoshio",
""
]
] |
Based on an assumption that an S_4 flavor symmetry is embedded into SU(3), a lepton mass matrix model is investigated. A Frogatt-Nielsen type model is assumed, and the flavor structures of the masses and mixing are caused by VEVs of SU(2)_L-singlet scalars \phi_u and \phi_d which are nonets (8+1) of the SU(3) flavor symmetry, and which are broken into 2+3+3' and 1 of S_4. If we require the invariance under the transformation (\phi^{(8)},\phi^{(1)}) \to (-\phi^{(8)},+\phi^{(1)}) for the superpotential of the nonet field \phi^{(8+1)}, the model leads to a beautiful relation for the charged lepton masses. The observed tribimaximal neutrino mixing is understood by assuming two SU(3) singlet right-handed neutrinos \nu_R^{(\pm)} and an SU(3) triplet scalar \chi.
|
1108.2856
|
Artem Lipatov
|
S.P. Baranov, A.V. Lipatov, N.P. Zotov
|
Prompt J/Psi production at LHC: new evidence for the kt-factorization
|
14 pages, 3 figures
|
Phs. Rev. D 85, 014034 (2012)
|
10.1103/PhysRevD.85.014034
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
In the framework of the kt-factorization approach, the production and
polarization of prompt J/Psi mesons in pp collisions at the LHC energy 7 TeV is
studied. Both the direct production mechanism as well as feed-down
contributions from chic1, chic2 and psi' decays are taken into account. Our
consideration is based on the color singlet model supplemented with the
off-shell matrix elements for the corresponding partonic subprocesses. The
unintegrated gluon densities in a proton are determined using the CCFM
evolution equation as well the Kimber-Martin-Ryskin prescription. We compare
our numerical predictions with the first experimental data taken by the CMS,
ATLAS and LHCb collaborations. The estimation of all polarization parameters
which determine J/Psi spin density matrix is performed.
|
[
{
"created": "Sun, 14 Aug 2011 10:21:59 GMT",
"version": "v1"
}
] |
2015-05-30
|
[
[
"Baranov",
"S. P.",
""
],
[
"Lipatov",
"A. V.",
""
],
[
"Zotov",
"N. P.",
""
]
] |
In the framework of the kt-factorization approach, the production and polarization of prompt J/Psi mesons in pp collisions at the LHC energy 7 TeV is studied. Both the direct production mechanism as well as feed-down contributions from chic1, chic2 and psi' decays are taken into account. Our consideration is based on the color singlet model supplemented with the off-shell matrix elements for the corresponding partonic subprocesses. The unintegrated gluon densities in a proton are determined using the CCFM evolution equation as well the Kimber-Martin-Ryskin prescription. We compare our numerical predictions with the first experimental data taken by the CMS, ATLAS and LHCb collaborations. The estimation of all polarization parameters which determine J/Psi spin density matrix is performed.
|
0806.4351
|
Frans Klinkhamer
|
F.R. Klinkhamer, M. Risse
|
Addendum: Ultrahigh-energy cosmic-ray bounds on nonbirefringent
modified-Maxwell theory
|
5 pages with revtex4
|
Phys.Rev.D77:117901,2008
|
10.1103/PhysRevD.77.117901
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Nonbirefringent modified-Maxwell theory, coupled to standard Dirac particles,
involves nine dimensionless parameters, which can be bounded by the inferred
absence of vacuum Cherenkov radiation for ultrahigh-energy cosmic rays
(UHECRs). With selected UHECR events, two-sided bounds on the eight
nonisotropic parameters are obtained at the 10^{-18} level, together with an
improved one-sided bound on the single isotropic parameter at the 10^{-19}
level.
|
[
{
"created": "Thu, 26 Jun 2008 15:56:13 GMT",
"version": "v1"
}
] |
2008-11-26
|
[
[
"Klinkhamer",
"F. R.",
""
],
[
"Risse",
"M.",
""
]
] |
Nonbirefringent modified-Maxwell theory, coupled to standard Dirac particles, involves nine dimensionless parameters, which can be bounded by the inferred absence of vacuum Cherenkov radiation for ultrahigh-energy cosmic rays (UHECRs). With selected UHECR events, two-sided bounds on the eight nonisotropic parameters are obtained at the 10^{-18} level, together with an improved one-sided bound on the single isotropic parameter at the 10^{-19} level.
|
hep-ph/0211187
|
Othmar Steinmann
|
Othmar Steinmann (University of Bielefeld, Germany)
|
What is the Magnetic Moment of the Electron?
|
24 pages, 4 figures, uses axodraw.sty
|
Commun.Math.Phys. 237 (2003) 181-201
|
10.1007/s00220-003-0847-z
| null |
hep-ph hep-th math-ph math.MP
| null |
A direct definition of the intrinsic magnetic moment of the electron is
given, which does not use infrared regularizations and interactions with
external fields. The expression does not depend on the unavoidable ambiguities
of the definition of a 1-electron state (exact form of its soft photon cloud).
The method leads to the same analytic expression as the conventional approach,
thus preserving the excellent agreement between theory and experiment.
|
[
{
"created": "Tue, 12 Nov 2002 22:15:19 GMT",
"version": "v1"
}
] |
2009-11-07
|
[
[
"Steinmann",
"Othmar",
"",
"University of Bielefeld, Germany"
]
] |
A direct definition of the intrinsic magnetic moment of the electron is given, which does not use infrared regularizations and interactions with external fields. The expression does not depend on the unavoidable ambiguities of the definition of a 1-electron state (exact form of its soft photon cloud). The method leads to the same analytic expression as the conventional approach, thus preserving the excellent agreement between theory and experiment.
|
2004.12877
|
Simone Biondini
|
Simone Biondini
|
Perturbative unitarity bounds for fermions composite models
|
10 pages, 3 figures, Contribution to Corfu Summer Institute 2019
"School and Workshops on Elementary Particle Physics and Gravity"
(CORFU2019). Drawn from arXiv:1903.12285
| null | null | null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Perturbative unitarity is a powerful tool for inferring the range of validity
of a given effective field theory. Here, we study such a bound in the parameter
space of dimension-5 and dimension-6 effective operators that arise in a
scenario of fermion compositeness. These operators are routinely used in
experimental searches at the LHC to constraint contact and gauge interactions
between ordinary Standard Model fermions and excited states of mass $M$. We
derive the unitarity bound for the production process of an excited neutrino,
then we implement such bound and compare it with the recent experimental
exclusion curves for Run 2, the High-Luminosity and High-Energy configurations
of the LHC. The results also apply to the searches where a generic single
excited state is produced via dimension-6 contact interactions. The unitarity
bound, so far overlooked in these effective models, is quite compelling and can
serve as a guide for exploring the parameter space ($M,\Lambda$) in addition to
the standard request $M \le \Lambda$.
|
[
{
"created": "Mon, 27 Apr 2020 15:32:38 GMT",
"version": "v1"
}
] |
2020-04-28
|
[
[
"Biondini",
"Simone",
""
]
] |
Perturbative unitarity is a powerful tool for inferring the range of validity of a given effective field theory. Here, we study such a bound in the parameter space of dimension-5 and dimension-6 effective operators that arise in a scenario of fermion compositeness. These operators are routinely used in experimental searches at the LHC to constraint contact and gauge interactions between ordinary Standard Model fermions and excited states of mass $M$. We derive the unitarity bound for the production process of an excited neutrino, then we implement such bound and compare it with the recent experimental exclusion curves for Run 2, the High-Luminosity and High-Energy configurations of the LHC. The results also apply to the searches where a generic single excited state is produced via dimension-6 contact interactions. The unitarity bound, so far overlooked in these effective models, is quite compelling and can serve as a guide for exploring the parameter space ($M,\Lambda$) in addition to the standard request $M \le \Lambda$.
|
1209.0701
|
Victor Goncalves
|
V.P. Goncalves, D. T. da Silva, W. K. Sauter
|
Meson production in two-photon interactions at energies available at
CERN Large Hadron Collider
|
5 pages, 1 figure, 4 tables. Version published in Physical Review C
|
Phys. Rev. C87, 028201 (2013)
|
10.1103/PhysRevC.87.028201
| null |
hep-ph hep-ex nucl-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The meson production cross sections are estimated considering photon-photon
interactions in hadron - hadron collisions at CERN LHC energies. We consider a
large number of mesons with photon-photon partial decay width well constrained
by the experiment and some mesons which are currently considered as hadronic
molecule and glueball candidates. Our results demonstrate that the experimental
analysis of these states is feasible at CERN - LHC.
|
[
{
"created": "Tue, 4 Sep 2012 16:47:55 GMT",
"version": "v1"
},
{
"created": "Fri, 5 Jul 2013 14:35:24 GMT",
"version": "v2"
}
] |
2014-05-27
|
[
[
"Goncalves",
"V. P.",
""
],
[
"da Silva",
"D. T.",
""
],
[
"Sauter",
"W. K.",
""
]
] |
The meson production cross sections are estimated considering photon-photon interactions in hadron - hadron collisions at CERN LHC energies. We consider a large number of mesons with photon-photon partial decay width well constrained by the experiment and some mesons which are currently considered as hadronic molecule and glueball candidates. Our results demonstrate that the experimental analysis of these states is feasible at CERN - LHC.
|
2205.05950
|
Jorge Segovia
|
B. Mart\'in-Gonz\'alez, P. G. Ortega, D. R. Entem, F. Fern\'andez and
J. Segovia
|
Towards the discovery of novel $B_c$ states: radiative and hadronic
transitions
|
13 pages, 9 tables. arXiv admin note: text overlap with
arXiv:1601.05093
| null |
10.1103/PhysRevD.106.054009
| null |
hep-ph hep-ex hep-lat nucl-ex nucl-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The properties of the $B_c$-meson family ($c\bar b$) are still not well
determined experimentally because the specific mechanisms of formation and
decay remain poorly understood. Unlike heavy quarkonia, i.e. the hidden heavy
quark-antiquark sectors of charmonium ($c\bar c$) and bottomonium ($b\bar b$),
the $B_c$-mesons cannot annihilate into gluons and they are, consequently, more
stable. The excited $B_c$ states, lying below the lowest strong-decay
$BD$-threshold, can only undergo through radiative decays and hadronic
transitions to the $B_c$ ground state, which then decays weakly. As a result of
this, a rich spectrum of narrow excited states below the $BD$-threshold appear,
whose total widths are two orders of magnitude smaller than those of the
excited levels of charmonium and bottomonium. In a different article, we
determined bottom-charmed meson masses using a non-relativistic constituent
quark model which has been applied to a wide range of hadron physical
observables, and thus the model parameters are completely constrained. Herein,
continuing to our study of the $B_c$ sector, we calculate the relevant
radiative decay widths and hadronic transition rates between $c\bar b$ states
which are below $BD$-threshold. This shall provide the most promising signals
for discovering excited $B_c$ states that are below the lowest strong-decay
$BD$-threshold. Finally, our results are compared with other models to measure
the reliability of the predictions and point out differences.
|
[
{
"created": "Thu, 12 May 2022 08:38:28 GMT",
"version": "v1"
},
{
"created": "Mon, 16 May 2022 13:16:02 GMT",
"version": "v2"
}
] |
2022-10-05
|
[
[
"Martín-González",
"B.",
""
],
[
"Ortega",
"P. G.",
""
],
[
"Entem",
"D. R.",
""
],
[
"Fernández",
"F.",
""
],
[
"Segovia",
"J.",
""
]
] |
The properties of the $B_c$-meson family ($c\bar b$) are still not well determined experimentally because the specific mechanisms of formation and decay remain poorly understood. Unlike heavy quarkonia, i.e. the hidden heavy quark-antiquark sectors of charmonium ($c\bar c$) and bottomonium ($b\bar b$), the $B_c$-mesons cannot annihilate into gluons and they are, consequently, more stable. The excited $B_c$ states, lying below the lowest strong-decay $BD$-threshold, can only undergo through radiative decays and hadronic transitions to the $B_c$ ground state, which then decays weakly. As a result of this, a rich spectrum of narrow excited states below the $BD$-threshold appear, whose total widths are two orders of magnitude smaller than those of the excited levels of charmonium and bottomonium. In a different article, we determined bottom-charmed meson masses using a non-relativistic constituent quark model which has been applied to a wide range of hadron physical observables, and thus the model parameters are completely constrained. Herein, continuing to our study of the $B_c$ sector, we calculate the relevant radiative decay widths and hadronic transition rates between $c\bar b$ states which are below $BD$-threshold. This shall provide the most promising signals for discovering excited $B_c$ states that are below the lowest strong-decay $BD$-threshold. Finally, our results are compared with other models to measure the reliability of the predictions and point out differences.
|
hep-ph/9508278
|
Douglas O. Carlson
|
Douglas O. Carlson
|
Physics of Single-Top Quark Production at Hadron Colliders
|
Thesis, 102 pages, Latex, needs 45 figures (not included). All Tex
files and the associated analysis package ONETOP may be obtained via
anonymous ftp at ftp://cteq14.pa.msu.edu/pub/carlson_d/
| null | null |
MSUHEP-050795
|
hep-ph
| null |
We discuss the physics of single-top quark production and decay at hadron
colliders, such as the Tevatron, the \tevstar~and the LHC. Our study includes
how to measure the mass and the width of the top quark produced from a
{\hbox{single-$t$}} or a single-$\bar t$ process. We also show how to probe new
physics by studying the couplings of $t$-${b}$-$W$ and show what can be
improved from measuring the production rate of single-top events. We also
discuss how to probe CP properties of the top quark by measuring the single-top
production rate. Finally, we present a Monte Carlo study on the detection of
single-top events in hadron collisions.
|
[
{
"created": "Wed, 9 Aug 1995 21:23:45 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Carlson",
"Douglas O.",
""
]
] |
We discuss the physics of single-top quark production and decay at hadron colliders, such as the Tevatron, the \tevstar~and the LHC. Our study includes how to measure the mass and the width of the top quark produced from a {\hbox{single-$t$}} or a single-$\bar t$ process. We also show how to probe new physics by studying the couplings of $t$-${b}$-$W$ and show what can be improved from measuring the production rate of single-top events. We also discuss how to probe CP properties of the top quark by measuring the single-top production rate. Finally, we present a Monte Carlo study on the detection of single-top events in hadron collisions.
|
1510.08261
|
Poonam Mehta
|
Mehedi Masud, Animesh Chatterjee, Poonam Mehta
|
Probing CP violation signal at DUNE in presence of non-standard neutrino
interactions
|
v2 : to appear in J. Phys. G
|
Journal of Physics G: Nuclear and Particle Physics, 43, 9, 095005
(2016)
|
10.1088/0954-3899/43/9/095005
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We discuss the impact of non-standard neutrino matter interactions (NSI) in
propagation on the determination of CP phase in the context of the long
baseline accelerator experiments such as Deep Underground Neutrino Experiment
(DUNE). DUNE will mainly address the issue of CP violation in the leptonic
sector. Here we study the role of NSI and its impact on the question of
observing the CP violation signal at DUNE. We consider two scenarios of
oscillation with three active neutrinos in absence and presence of NSI. We
elucidate the importance of ruling out subdominant new physics effects
introduced by NSI in inferring CP violation signal at DUNE by considering NSI
terms collectively as well as by exploiting the non-trivial interplay of moduli
and phases of the NSI terms. We demonstrate the existence of NSI-SI
degeneracies which need to be eliminated in reliable manner in order to make
conclusive statements about the CP phase.
|
[
{
"created": "Wed, 28 Oct 2015 11:31:56 GMT",
"version": "v1"
},
{
"created": "Wed, 22 Jun 2016 17:12:21 GMT",
"version": "v2"
}
] |
2016-08-24
|
[
[
"Masud",
"Mehedi",
""
],
[
"Chatterjee",
"Animesh",
""
],
[
"Mehta",
"Poonam",
""
]
] |
We discuss the impact of non-standard neutrino matter interactions (NSI) in propagation on the determination of CP phase in the context of the long baseline accelerator experiments such as Deep Underground Neutrino Experiment (DUNE). DUNE will mainly address the issue of CP violation in the leptonic sector. Here we study the role of NSI and its impact on the question of observing the CP violation signal at DUNE. We consider two scenarios of oscillation with three active neutrinos in absence and presence of NSI. We elucidate the importance of ruling out subdominant new physics effects introduced by NSI in inferring CP violation signal at DUNE by considering NSI terms collectively as well as by exploiting the non-trivial interplay of moduli and phases of the NSI terms. We demonstrate the existence of NSI-SI degeneracies which need to be eliminated in reliable manner in order to make conclusive statements about the CP phase.
|
hep-ph/9512274
| null |
Piotr Zenczykowski (Inst.Nucl.Physics, Krakow)
|
The puzzle of the quark model: Weak radiative hyperon decays
|
10 pages, LaTeX, reformatted to dispense with the use of the
espcrc2.sty file, to appear in the Proceedings of the conference "Production
and Decay of Hyperons, Charm and Beauty Hadrons", Strasbourg, September 5-8,
1995
|
Nucl.Phys.Proc.Suppl. 50 (1996) 211-215
|
10.1016/0920-5632(96)00393-3
|
1702/PH - INP, Krakow, November 1995
|
hep-ph
| null |
Weak radiative hyperon decays present us with a long-standing puzzle, namely
the question of validity of a hadron-level theorem proved by Hara. We briefly
discuss the conflict between expectations based on Hara's theorem and
experiment as well as the way in which the quark model evades the theorem.
Violation of Hara's theorem in the quark model is traced back to the issue of
hadron compositeness and the nonequivalence of standard ways of imposing
gauge-invariance condition at quark and hadron levels. This suggests that our
understanding of nonlocal composite nature of hadrons may require some
important change.
|
[
{
"created": "Mon, 11 Dec 1995 13:36:00 GMT",
"version": "v1"
},
{
"created": "Thu, 14 Dec 1995 12:09:00 GMT",
"version": "v2"
}
] |
2009-10-28
|
[
[
"Zenczykowski",
"Piotr",
"",
"Inst.Nucl.Physics, Krakow"
]
] |
Weak radiative hyperon decays present us with a long-standing puzzle, namely the question of validity of a hadron-level theorem proved by Hara. We briefly discuss the conflict between expectations based on Hara's theorem and experiment as well as the way in which the quark model evades the theorem. Violation of Hara's theorem in the quark model is traced back to the issue of hadron compositeness and the nonequivalence of standard ways of imposing gauge-invariance condition at quark and hadron levels. This suggests that our understanding of nonlocal composite nature of hadrons may require some important change.
|
0907.3403
|
Marco Ruggieri
|
Marco Ruggieri
|
On the critical end point of the QCD and the NJL model phase diagrams
|
6 pages, 1 figure. Talk given at IFAE 2009, Bari, 15-17 April 2009.
The original publication is available at:
http://www.sif.it/SIF/en/portal/journals
|
Nuovo Cim.C32N3-4:77-80,2009
|
10.1393/ncc/i2009-10441-5
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
In this talk I compare the knowledge on the critical end point of the QCD
phase diagram grasped from lattice calculations, with that obtained from
Nambu--Jona-Lasinio (NJL) model computations. The original publication is
available at http://www.sif.it/SIF/en/portal/journals
|
[
{
"created": "Mon, 20 Jul 2009 13:56:05 GMT",
"version": "v1"
}
] |
2014-11-20
|
[
[
"Ruggieri",
"Marco",
""
]
] |
In this talk I compare the knowledge on the critical end point of the QCD phase diagram grasped from lattice calculations, with that obtained from Nambu--Jona-Lasinio (NJL) model computations. The original publication is available at http://www.sif.it/SIF/en/portal/journals
|
1001.3432
|
Ho-Meoyng Choi
|
Ho-Meoyng Choi (Kyungpook National University)
|
Light-front quark model analysis of the exclusive rare $B_c\to
D_{(s)}(\ell^+\ell^-,\nu_{\ell}\bar{\nu}_{\ell})$ decays
|
11 pages, 8figures, version to appear in Phys. Rev. D
|
Phys.Rev.D81:054003,2010
|
10.1103/PhysRevD.81.054003
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We investigate the exclusive rare $B_c\to D_{(s)}\nu_{\ell}\bar{\nu_{\ell}}$
and $B\to D_{(s)}\ell^+\ell^-$ ($\ell=e,\mu,\tau$) decays within the standard
model and the light-front quark model constrained by the variational principle
for the QCD motivated effective Hamiltonian. The form factors $f_{\pm}(q^2)$
and $f_T(q^2)$ are obtained from the analytic continuation method in the
$q^+=0$ frame. While the form factors $f_+(q^2)$ and $f_T(q^2)$ are free from
the zero-mode, the form factor $f_-(q^2)$ is not free from the zero-mode in the
$q^+=0$ frame. We discuss the covariance(i.e. frame-independence) of our model
calculation and quantify the zero-mode contributions to $f_-(q^2)$ for $B_c\to
D_{(s)}$ decays. The branching ratios and the longitudinal lepton polarization
asymmetries are calculated with and without the long-distance contributions.
Our numerical results for the non-resonant branching ratios for $B_c\to
D(D_s)\sum\nu_{\ell}\bar{\nu_{\ell}}$ and $B_c\to D(D_s)\ell^+\ell^-$ are in
the order of $10^{-8} (10^{-7})$ and $10^{-9} (10^{-8})$, respectively. The
averaged values of the lepton polarization asymmetries obtained from the linear
(harmonic oscillator) potential parameters are found to be $-0.99 (-0.99)$ for
$B_c\to D\mu^+\mu^-$ and $-0.16 (-0.15)$ for $B_c\to D\tau^+\tau^-$, and $-0.98
(-0.98)$ for $B_c\to D_s\mu^+\mu^-$ and $-0.14 (-0.12)$ for $B_c\to
D_s\tau^+\tau^-$, respectively.
|
[
{
"created": "Tue, 19 Jan 2010 23:34:34 GMT",
"version": "v1"
},
{
"created": "Sat, 30 Jan 2010 02:28:15 GMT",
"version": "v2"
},
{
"created": "Fri, 12 Feb 2010 00:48:41 GMT",
"version": "v3"
}
] |
2010-04-06
|
[
[
"Choi",
"Ho-Meoyng",
"",
"Kyungpook National University"
]
] |
We investigate the exclusive rare $B_c\to D_{(s)}\nu_{\ell}\bar{\nu_{\ell}}$ and $B\to D_{(s)}\ell^+\ell^-$ ($\ell=e,\mu,\tau$) decays within the standard model and the light-front quark model constrained by the variational principle for the QCD motivated effective Hamiltonian. The form factors $f_{\pm}(q^2)$ and $f_T(q^2)$ are obtained from the analytic continuation method in the $q^+=0$ frame. While the form factors $f_+(q^2)$ and $f_T(q^2)$ are free from the zero-mode, the form factor $f_-(q^2)$ is not free from the zero-mode in the $q^+=0$ frame. We discuss the covariance(i.e. frame-independence) of our model calculation and quantify the zero-mode contributions to $f_-(q^2)$ for $B_c\to D_{(s)}$ decays. The branching ratios and the longitudinal lepton polarization asymmetries are calculated with and without the long-distance contributions. Our numerical results for the non-resonant branching ratios for $B_c\to D(D_s)\sum\nu_{\ell}\bar{\nu_{\ell}}$ and $B_c\to D(D_s)\ell^+\ell^-$ are in the order of $10^{-8} (10^{-7})$ and $10^{-9} (10^{-8})$, respectively. The averaged values of the lepton polarization asymmetries obtained from the linear (harmonic oscillator) potential parameters are found to be $-0.99 (-0.99)$ for $B_c\to D\mu^+\mu^-$ and $-0.16 (-0.15)$ for $B_c\to D\tau^+\tau^-$, and $-0.98 (-0.98)$ for $B_c\to D_s\mu^+\mu^-$ and $-0.14 (-0.12)$ for $B_c\to D_s\tau^+\tau^-$, respectively.
|
hep-ph/9411252
|
Mikko Laine
|
M. Laine
|
Gauge Dependence of the High-Temperature 2-Loop Effective Potential for
the Higgs Field
|
13 LaTeX-pages + 2 ps-figure (Instructions added to uudecode the
ps-file.)
|
Phys.Rev.D51:4525-4532,1995
|
10.1103/PhysRevD.51.4525
|
HU-TFT-94-46
|
hep-ph
| null |
The high-temperature limit of the 2-loop effective potential for the Higgs
field is calculated from an effective 3d theory, in a general covariant gauge.
It is shown explicitly that a gauge-independent result can be extracted for the
equation of state from the gauge-dependent effective potential. The convergence
of perturbation theory is estimated in the broken phase, utilizing the gauge
dependence of the effective potential.
|
[
{
"created": "Wed, 9 Nov 1994 14:29:38 GMT",
"version": "v1"
},
{
"created": "Thu, 10 Nov 1994 08:42:53 GMT",
"version": "v2"
}
] |
2010-11-01
|
[
[
"Laine",
"M.",
""
]
] |
The high-temperature limit of the 2-loop effective potential for the Higgs field is calculated from an effective 3d theory, in a general covariant gauge. It is shown explicitly that a gauge-independent result can be extracted for the equation of state from the gauge-dependent effective potential. The convergence of perturbation theory is estimated in the broken phase, utilizing the gauge dependence of the effective potential.
|
2101.12111
|
Thomas Heinzl
|
T. Heinzl, A. Ilderton and B. King
|
Classical resummation and breakdown of strong-field QED
|
8 pages, 2 figures; v2: Journal version with Supplementaries added
|
Phys. Rev. Lett. 127, 061601 (2021)
|
10.1103/PhysRevLett.127.061601
| null |
hep-ph
|
http://creativecommons.org/licenses/by-nc-nd/4.0/
|
QED perturbation theory has been conjectured to break down in sufficiently
strong backgrounds, obstructing the analysis of strong-field physics. We show
that the breakdown occurs even in classical electrodynamics, at lower field
strengths than previously considered, and that it may be cured by resummation.
As a consequence, an analogous resummation is required in QED. A detailed
investigation shows, for a range of observables, that unitarity removes
diagrams previously believed to be responsible for the breakdown of QED
perturbation theory.
|
[
{
"created": "Thu, 28 Jan 2021 16:58:33 GMT",
"version": "v1"
},
{
"created": "Mon, 26 Jul 2021 16:26:13 GMT",
"version": "v2"
}
] |
2021-08-11
|
[
[
"Heinzl",
"T.",
""
],
[
"Ilderton",
"A.",
""
],
[
"King",
"B.",
""
]
] |
QED perturbation theory has been conjectured to break down in sufficiently strong backgrounds, obstructing the analysis of strong-field physics. We show that the breakdown occurs even in classical electrodynamics, at lower field strengths than previously considered, and that it may be cured by resummation. As a consequence, an analogous resummation is required in QED. A detailed investigation shows, for a range of observables, that unitarity removes diagrams previously believed to be responsible for the breakdown of QED perturbation theory.
|
2110.14826
|
Alfredo Vega Dr.
|
Alfredo Vega and Amanda Rodriguez
|
Effects of beta function on mass and melting temperature for scalar
glueballs in AdS/QCD models at finite temperature
|
6 pages, 3 figures
| null |
10.1140/epja/s10050-022-00807-6
| null |
hep-ph hep-th
|
http://creativecommons.org/publicdomain/zero/1.0/
|
We consider an extension to finite temperature in an AdS/ QCD model, which
regards anomalous dimension contributions to get a bulk mass depending on beta
function. We study the effect of beta function on mass as a function of
temperature and melting temperature for scalar glueballs.
|
[
{
"created": "Thu, 28 Oct 2021 00:27:52 GMT",
"version": "v1"
}
] |
2022-09-21
|
[
[
"Vega",
"Alfredo",
""
],
[
"Rodriguez",
"Amanda",
""
]
] |
We consider an extension to finite temperature in an AdS/ QCD model, which regards anomalous dimension contributions to get a bulk mass depending on beta function. We study the effect of beta function on mass as a function of temperature and melting temperature for scalar glueballs.
|
0908.0251
|
Ted Rogers
|
T.C. Rogers, M. Strikman
|
Multiple Hard Partonic Collisions with Correlations in Proton-Proton
Scattering
|
Typos fixed, Figures 2,9 and 10 added, matches version published in
Phys. Rev. D
|
Phys.Rev.D81:016013,2010
|
10.1103/PhysRevD.81.016013
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We propose a simple method for incorporating correlations into the impact
parameter space description of multiple (semi-)hard partonic collisions in high
energy hadron-hadron scattering. The perturbative QCD input is the standard
factorization theorem for inclusive dijet production with a lower cutoff on
transverse momentum. The width of the transverse distribution of hard partons
is fixed by parameterizations of the two-gluon form factor. We then reconstruct
the hard contribution to the total inelastic profile function and obtain
corrections due to correlations to the more commonly used eikonal description.
Estimates of the size of double correlation corrections are based on the rate
of double collisions measured at the Tevatron. We find that, if typical values
for the lower transverse momentum cutoff are used in the calculation of the
inclusive hard dijet cross section, then the correlation corrections are
necessary for maintaining consistency with expectations for the total inelastic
proton-proton cross section at LHC energies.
|
[
{
"created": "Mon, 3 Aug 2009 13:50:07 GMT",
"version": "v1"
},
{
"created": "Mon, 25 Jan 2010 12:55:02 GMT",
"version": "v2"
}
] |
2010-04-06
|
[
[
"Rogers",
"T. C.",
""
],
[
"Strikman",
"M.",
""
]
] |
We propose a simple method for incorporating correlations into the impact parameter space description of multiple (semi-)hard partonic collisions in high energy hadron-hadron scattering. The perturbative QCD input is the standard factorization theorem for inclusive dijet production with a lower cutoff on transverse momentum. The width of the transverse distribution of hard partons is fixed by parameterizations of the two-gluon form factor. We then reconstruct the hard contribution to the total inelastic profile function and obtain corrections due to correlations to the more commonly used eikonal description. Estimates of the size of double correlation corrections are based on the rate of double collisions measured at the Tevatron. We find that, if typical values for the lower transverse momentum cutoff are used in the calculation of the inclusive hard dijet cross section, then the correlation corrections are necessary for maintaining consistency with expectations for the total inelastic proton-proton cross section at LHC energies.
|
0905.1572
|
Vincent Tisserand
|
Vincent Tisserand (CKMFitter group)
|
CKM fits as of winter 2009 and sensitivity to New Physics
|
proceedings for the Moriond 2009 EW session
| null | null | null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We present the status of the CKM matrix parameters in the framework of the
Standard Model. We perform a model independent analysis to set constraints on
additional effective parameters accounting for possible New Physics effects and
to evaluate the present allowed space for these effects both from $B_d$ and
$B_s$ mesons.
|
[
{
"created": "Mon, 11 May 2009 08:48:01 GMT",
"version": "v1"
},
{
"created": "Mon, 25 May 2009 09:15:36 GMT",
"version": "v2"
}
] |
2009-05-25
|
[
[
"Tisserand",
"Vincent",
"",
"CKMFitter group"
]
] |
We present the status of the CKM matrix parameters in the framework of the Standard Model. We perform a model independent analysis to set constraints on additional effective parameters accounting for possible New Physics effects and to evaluate the present allowed space for these effects both from $B_d$ and $B_s$ mesons.
|
1107.5925
|
Hayriye Sundu
|
K. Azizi, Y. Sarac, H. Sundu
|
Light cone QCD sum rules study of the semileptonic heavy $\Xi_{Q}$ and
$\Xi'_{Q}$ transitions to $\Xi$ and $\Sigma $ baryons
|
30 Pages, 5 Figures and 18 Tables
| null |
10.1140/epja/i2012-12002-1
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The semileptonic decays of heavy spin--1/2, $\Xi_{b(c)}$ and $\Xi'_{b(c)}$
baryons to the light spin-- 1/2, $\Xi$ and $\Sigma $ baryons are investigated
in the framework of the light cone QCD sum rules. In particular, using the most
general form of the interpolating currents for the heavy baryons as well as the
distribution amplitudes of the $\Xi$ and $\Sigma $ baryons, we calculate all
form factors entering the matrix elements of the corresponding effective
Hamiltonians in full QCD. Having calculated the responsible form factors, we
evaluate the decay rates and branching fractions of the related transitions.
|
[
{
"created": "Fri, 29 Jul 2011 10:51:55 GMT",
"version": "v1"
},
{
"created": "Sun, 27 Nov 2011 21:53:42 GMT",
"version": "v2"
}
] |
2015-05-30
|
[
[
"Azizi",
"K.",
""
],
[
"Sarac",
"Y.",
""
],
[
"Sundu",
"H.",
""
]
] |
The semileptonic decays of heavy spin--1/2, $\Xi_{b(c)}$ and $\Xi'_{b(c)}$ baryons to the light spin-- 1/2, $\Xi$ and $\Sigma $ baryons are investigated in the framework of the light cone QCD sum rules. In particular, using the most general form of the interpolating currents for the heavy baryons as well as the distribution amplitudes of the $\Xi$ and $\Sigma $ baryons, we calculate all form factors entering the matrix elements of the corresponding effective Hamiltonians in full QCD. Having calculated the responsible form factors, we evaluate the decay rates and branching fractions of the related transitions.
|
1904.05893
|
Jeong Han Kim
|
Jeong Han Kim, Samuel D. Lane, Hye-Sung Lee, Ian M. Lewis, and Matthew
Sullivan
|
Searching for Dark Photons with Maverick Top Partners
|
40 pages and 11 figures
|
Phys. Rev. D 101, 035041 (2020)
|
10.1103/PhysRevD.101.035041
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
In this paper, we present a model in which an up-type vector-like quark (VLQ)
is charged under a new $U(1)_d$ gauge force which kinetically mixes with the SM
hypercharge. The gauge boson of the $U(1)_d$ is the dark photon, $\gamma_d$.
Traditional searches for VLQs rely on decays into Standard Model electroweak
bosons $W,Z$ or Higgs. However, since no evidence for VLQs has been found at
the Large Hadron Collider (LHC), it is imperative to search for other novel
signatures of VLQs beyond their traditional decays. As we will show, if the
dark photon is much less massive than the Standard Model electroweak sector,
$M_{\gamma_d}\ll M_Z$, for the large majority of the allowed parameter space
the VLQ predominately decays into the dark photon and the dark Higgs that
breaks the $U(1)_d$ . That is, this VLQ is a `maverick top partner' with
nontraditional decays. One of the appeals of this scenario is that pair
production of the VLQ at the LHC occurs through the strong force and the rate
is determined by the gauge structure. Hence, the production of the dark photon
at the LHC only depends on the strong force and is largely independent of the
small kinetic mixing with hypercharge. This scenario provides a robust
framework to search for a light dark sector via searches for heavy colored
particles at the LHC.
|
[
{
"created": "Thu, 11 Apr 2019 18:00:00 GMT",
"version": "v1"
},
{
"created": "Mon, 24 Apr 2023 15:26:38 GMT",
"version": "v2"
}
] |
2023-04-25
|
[
[
"Kim",
"Jeong Han",
""
],
[
"Lane",
"Samuel D.",
""
],
[
"Lee",
"Hye-Sung",
""
],
[
"Lewis",
"Ian M.",
""
],
[
"Sullivan",
"Matthew",
""
]
] |
In this paper, we present a model in which an up-type vector-like quark (VLQ) is charged under a new $U(1)_d$ gauge force which kinetically mixes with the SM hypercharge. The gauge boson of the $U(1)_d$ is the dark photon, $\gamma_d$. Traditional searches for VLQs rely on decays into Standard Model electroweak bosons $W,Z$ or Higgs. However, since no evidence for VLQs has been found at the Large Hadron Collider (LHC), it is imperative to search for other novel signatures of VLQs beyond their traditional decays. As we will show, if the dark photon is much less massive than the Standard Model electroweak sector, $M_{\gamma_d}\ll M_Z$, for the large majority of the allowed parameter space the VLQ predominately decays into the dark photon and the dark Higgs that breaks the $U(1)_d$ . That is, this VLQ is a `maverick top partner' with nontraditional decays. One of the appeals of this scenario is that pair production of the VLQ at the LHC occurs through the strong force and the rate is determined by the gauge structure. Hence, the production of the dark photon at the LHC only depends on the strong force and is largely independent of the small kinetic mixing with hypercharge. This scenario provides a robust framework to search for a light dark sector via searches for heavy colored particles at the LHC.
|
hep-ph/9806541
|
Sharon Jensen
|
John R. Hiller and Stanley J. Brodsky
|
Nonperturbative renormalization and the electron's anomalous moment in
large-alpha QED
|
RevTex, 35 pages
|
Phys.Rev.D59:016006,1999
|
10.1103/PhysRevD.59.016006
|
SLAC-PUB-7833 and UMN-D-98-2
|
hep-ph
| null |
We study the physical electron in quantum electrodynamics expanded on the
light-cone Fock space in order to address two problems: (1) the physics of the
electron's anomalous magnetic moment $a_e$ in nonperturbative QED, and (2) the
practical problems of ultraviolet regularization and renormalization in
truncated nonperturbative light-cone Hamiltonian theory. We present results for
$a_e$ computed in a light-cone gauge Fock space truncated to include one bare
electron and at most two photons; i.e., up to two photons in flight. The
calculational scheme uses an invariant mass cutoff, discretized light-cone
quantization (DLCQ), a Tamm--Dancoff truncation of the Fock space, and a photon
mass regulator. We introduce new weighting methods which greatly improve
convergence to the continuum within DLCQ. Nonperturbative renormalization of
the coupling and electron mass are carried out, and a limit on the magnitude of
the effective physical coupling strength is computed. A large renormalized
coupling strength $\alpha_R= 0.1$ is then used to make the nonperturbative
effects in the electron anomalous moment from the one-electron, two-photon Fock
state sector numerically detectable.
|
[
{
"created": "Tue, 30 Jun 1998 23:25:54 GMT",
"version": "v1"
}
] |
2009-09-11
|
[
[
"Hiller",
"John R.",
""
],
[
"Brodsky",
"Stanley J.",
""
]
] |
We study the physical electron in quantum electrodynamics expanded on the light-cone Fock space in order to address two problems: (1) the physics of the electron's anomalous magnetic moment $a_e$ in nonperturbative QED, and (2) the practical problems of ultraviolet regularization and renormalization in truncated nonperturbative light-cone Hamiltonian theory. We present results for $a_e$ computed in a light-cone gauge Fock space truncated to include one bare electron and at most two photons; i.e., up to two photons in flight. The calculational scheme uses an invariant mass cutoff, discretized light-cone quantization (DLCQ), a Tamm--Dancoff truncation of the Fock space, and a photon mass regulator. We introduce new weighting methods which greatly improve convergence to the continuum within DLCQ. Nonperturbative renormalization of the coupling and electron mass are carried out, and a limit on the magnitude of the effective physical coupling strength is computed. A large renormalized coupling strength $\alpha_R= 0.1$ is then used to make the nonperturbative effects in the electron anomalous moment from the one-electron, two-photon Fock state sector numerically detectable.
|
hep-ph/9305246
|
Kim Milton
|
Carl M. Bender, Lawrence R. Mead, and Kimball A. Milton
|
Discrete Time Quantum Mechanics
|
52 pages, OKHEP-93-07
| null | null | null |
hep-ph
| null |
This paper summarizes a research program that has been underway for a decade.
The objective is to find a fast and accurate scheme for solving quantum
problems which does not involve a Monte Carlo algorithm. We use an alternative
strategy based on the method of finite elements. We are able to formulate fully
consistent quantum-mechanical systems directly on a lattice in terms of
operator difference equations. One advantage of this discretized formulation of
quantum mechanics is that the ambiguities associated with operator ordering are
eliminated. Furthermore, the scheme provides an easy way in which to obtain the
energy levels of the theory numerically. A generalized version of this
discretization scheme can be applied to quantum field theory problems. The
difficulties normally associated with fermion doubling are eliminated. Also,
one can incorporate local gauge invariance in the finite-element formulation.
Results for some field theory models are summarized. In particular, we review
the calculation of the anomaly in two-dimensional quantum electrodynamics (the
Schwinger model). Finally, we discuss nonabelian gauge theories.
|
[
{
"created": "Tue, 11 May 1993 21:25:42 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Bender",
"Carl M.",
""
],
[
"Mead",
"Lawrence R.",
""
],
[
"Milton",
"Kimball A.",
""
]
] |
This paper summarizes a research program that has been underway for a decade. The objective is to find a fast and accurate scheme for solving quantum problems which does not involve a Monte Carlo algorithm. We use an alternative strategy based on the method of finite elements. We are able to formulate fully consistent quantum-mechanical systems directly on a lattice in terms of operator difference equations. One advantage of this discretized formulation of quantum mechanics is that the ambiguities associated with operator ordering are eliminated. Furthermore, the scheme provides an easy way in which to obtain the energy levels of the theory numerically. A generalized version of this discretization scheme can be applied to quantum field theory problems. The difficulties normally associated with fermion doubling are eliminated. Also, one can incorporate local gauge invariance in the finite-element formulation. Results for some field theory models are summarized. In particular, we review the calculation of the anomaly in two-dimensional quantum electrodynamics (the Schwinger model). Finally, we discuss nonabelian gauge theories.
|
1207.5771
|
K. S. Babu
|
K. S. Babu, R. N. Mohapatra
|
B-L Violating Proton Decay Modes and New Baryogenesis Scenario in SO(10)
|
To be published in Phys. Rev. Lett., 9 pages. arXiv admin note: text
overlap with arXiv:1203.5544
| null |
10.1103/PhysRevLett.109.091803
|
OSU-HEP-12-08
|
hep-ph hep-ex
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We show that grand unified theories based on SO(10) generate quite naturally
baryon number violating dimension seven operators that violate (B-L), and lead
to novel nucleon decay modes such as n \to e^-K^+, e^- \pi^+ and p \to \nu
\pi^+. We find that in two-step breaking schemes of non-supersymmetric SO(10),
the partial lifetimes for these modes can be within reach of experiments. The
interactions responsible for these decay modes also provide a new way to
understand the origin of matter in the universe via the decays of GUT scale
scalar bosons of SO(10). Their (B-L)-violating nature guarantees that the GUT
scale induced baryon asymmetry is not washed out by the electroweak sphaleron
interactions. In minimal SO(10) models this asymmetry is closely tied to the
masses of quarks, leptons and the neutrinos.
|
[
{
"created": "Tue, 24 Jul 2012 18:59:27 GMT",
"version": "v1"
}
] |
2015-06-05
|
[
[
"Babu",
"K. S.",
""
],
[
"Mohapatra",
"R. N.",
""
]
] |
We show that grand unified theories based on SO(10) generate quite naturally baryon number violating dimension seven operators that violate (B-L), and lead to novel nucleon decay modes such as n \to e^-K^+, e^- \pi^+ and p \to \nu \pi^+. We find that in two-step breaking schemes of non-supersymmetric SO(10), the partial lifetimes for these modes can be within reach of experiments. The interactions responsible for these decay modes also provide a new way to understand the origin of matter in the universe via the decays of GUT scale scalar bosons of SO(10). Their (B-L)-violating nature guarantees that the GUT scale induced baryon asymmetry is not washed out by the electroweak sphaleron interactions. In minimal SO(10) models this asymmetry is closely tied to the masses of quarks, leptons and the neutrinos.
|
1911.00213
|
Jiajun Liao
|
Jiajun Liao, Newton Nath, TseChun Wang, Ye-Ling Zhou
|
Nonstandard neutrino interactions and mu-tau reflection symmetry
|
24 pages, 6 figures. Version to appear in PRD
|
Phys. Rev. D 101, 095036 (2020)
|
10.1103/PhysRevD.101.095036
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Nonstandard interactions (NSIs), possible subleading effects originating from
new physics beyond the Standard Model, may affect the propagation of neutrinos
and eventually contribute to measurements of neutrino oscillations. Besides
this, $ \mu-\tau $ reflection symmetry, naturally predicted by non-Abelian
discrete flavor symmetries, has been very successful in explaining the observed
leptonic mixing patterns. In this work, we study the combined effect of both.
We present an $S_4$ flavor model with $\mu-\tau$ reflection symmetry realized
in both neutrino masses and NSIs. Under this formalism, we perform a detailed
study for the upcoming neutrino experiments DUNE and T2HK. Our simulation
results show that under the $\mu-\tau $ reflection symmetry, NSI parameters are
further constrained and the mass ordering sensitivity is less affected by the
presence of NSIs.
|
[
{
"created": "Fri, 1 Nov 2019 05:58:35 GMT",
"version": "v1"
},
{
"created": "Wed, 27 May 2020 09:13:13 GMT",
"version": "v2"
}
] |
2020-06-03
|
[
[
"Liao",
"Jiajun",
""
],
[
"Nath",
"Newton",
""
],
[
"Wang",
"TseChun",
""
],
[
"Zhou",
"Ye-Ling",
""
]
] |
Nonstandard interactions (NSIs), possible subleading effects originating from new physics beyond the Standard Model, may affect the propagation of neutrinos and eventually contribute to measurements of neutrino oscillations. Besides this, $ \mu-\tau $ reflection symmetry, naturally predicted by non-Abelian discrete flavor symmetries, has been very successful in explaining the observed leptonic mixing patterns. In this work, we study the combined effect of both. We present an $S_4$ flavor model with $\mu-\tau$ reflection symmetry realized in both neutrino masses and NSIs. Under this formalism, we perform a detailed study for the upcoming neutrino experiments DUNE and T2HK. Our simulation results show that under the $\mu-\tau $ reflection symmetry, NSI parameters are further constrained and the mass ordering sensitivity is less affected by the presence of NSIs.
|
hep-ph/0011144
|
Liangsb
|
Chongxing Yue, Guoli Liu, Jiantao Li
|
The bound on the mass of the new gauge boson $Z^{\prime}$ from the
process $\mu\longrightarrow 3e$
|
Latex file, 9 Pages 2 eps figures. to be published Phys.Lett.B
|
Phys.Lett. B496 (2000) 89-92
|
10.1016/S0370-2693(00)01257-0
| null |
hep-ph
| null |
The new gauge boson $Z^{\prime}$ predicted by the strong top dynamical
symmetry breaking models has significant contributions to the lepton flavor
changing process $\mu\longrightarrow 3e $. We consider the bound on the mass of
the new gauge boson $Z^{\prime}$ from the experimental value of the branching
ratio $Br(\mu\longrightarrow 3e)$ in the framework of topcolor assisted
technicolor models. We find that the precision experimental value of
$Br(\mu\longrightarrow 3e)$ gives a severe bound on the $Z^{\prime}$ mass
$M_{Z^{\prime}}$. For $k_1 \leq 1$, $M_{Z^{\prime}}$ must be larger than 1.64
$TeV$.
|
[
{
"created": "Fri, 10 Nov 2000 07:40:55 GMT",
"version": "v1"
}
] |
2009-10-31
|
[
[
"Yue",
"Chongxing",
""
],
[
"Liu",
"Guoli",
""
],
[
"Li",
"Jiantao",
""
]
] |
The new gauge boson $Z^{\prime}$ predicted by the strong top dynamical symmetry breaking models has significant contributions to the lepton flavor changing process $\mu\longrightarrow 3e $. We consider the bound on the mass of the new gauge boson $Z^{\prime}$ from the experimental value of the branching ratio $Br(\mu\longrightarrow 3e)$ in the framework of topcolor assisted technicolor models. We find that the precision experimental value of $Br(\mu\longrightarrow 3e)$ gives a severe bound on the $Z^{\prime}$ mass $M_{Z^{\prime}}$. For $k_1 \leq 1$, $M_{Z^{\prime}}$ must be larger than 1.64 $TeV$.
|
2008.10742
|
Cristian Villavicencio
|
C. A. Dominguez, Luis A. Hern\'andez, Marcelo Loewe, Cristian
Villavicencio, R. Zamora
|
Magnetic field dependence of nucleon parameters from QCD sum rules
|
Note added in proof. Accepted for publication in Phys. Rev. D
|
Phys. Rev. D 102, 094007 (2020)
|
10.1103/PhysRevD.102.094007
| null |
hep-ph nucl-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Finite energy QCD sum rules involving nucleon current correlators are used to
determine several QCD and hadronic parameters in the presence of an external,
uniform, large magnetic field. The continuum hadronic threshold $s_0$, nucleon
mass $m_N$, current-nucleon coupling $\lambda_N$, transverse velocity
$v_\perp$, the spin polarization condensate $\langle\bar q\sigma_{12}
q\rangle$, and the magnetic susceptibility of the quark condensate $\chi_q$,
are obtained for the case of protons and neutrons. Due to the magnetic field,
and charge asymmetry of light quarks up and down, all the obtained quantities
evolve differently with the magnetic field, for each nucleon or quark flavor.
With this approach it is possible to obtain the evolution of the above
parameters up to a magnetic field strength $eB < 1.4$ GeV$^2$.
|
[
{
"created": "Mon, 24 Aug 2020 23:14:42 GMT",
"version": "v1"
},
{
"created": "Mon, 31 Aug 2020 15:05:38 GMT",
"version": "v2"
},
{
"created": "Fri, 6 Nov 2020 04:47:06 GMT",
"version": "v3"
}
] |
2020-11-18
|
[
[
"Dominguez",
"C. A.",
""
],
[
"Hernández",
"Luis A.",
""
],
[
"Loewe",
"Marcelo",
""
],
[
"Villavicencio",
"Cristian",
""
],
[
"Zamora",
"R.",
""
]
] |
Finite energy QCD sum rules involving nucleon current correlators are used to determine several QCD and hadronic parameters in the presence of an external, uniform, large magnetic field. The continuum hadronic threshold $s_0$, nucleon mass $m_N$, current-nucleon coupling $\lambda_N$, transverse velocity $v_\perp$, the spin polarization condensate $\langle\bar q\sigma_{12} q\rangle$, and the magnetic susceptibility of the quark condensate $\chi_q$, are obtained for the case of protons and neutrons. Due to the magnetic field, and charge asymmetry of light quarks up and down, all the obtained quantities evolve differently with the magnetic field, for each nucleon or quark flavor. With this approach it is possible to obtain the evolution of the above parameters up to a magnetic field strength $eB < 1.4$ GeV$^2$.
|
2107.09493
|
Rui Santos
|
Felipe F. Freitas, Carlos A. R. Herdeiro, Ant\'onio P. Morais,
Ant\'onio Onofre, Roman Pasechnik, Eugen Radu, Nicolas Sanchis-Gual, Rui
Santos
|
Ultralight bosons for strong gravity applications from simple Standard
Model extensions
|
27 pages, 2 figures
| null |
10.1088/1475-7516/2021/12/047
| null |
hep-ph astro-ph.HE gr-qc hep-th
|
http://creativecommons.org/licenses/by/4.0/
|
We construct families, and concrete examples, of simple extensions of the
Standard Model that can yield ultralight {real or} complex vectors or scalars
with potential astrophysical relevance. Specifically, the mass range for these
putative fundamental bosons ($\sim 10^{-10}-10^{-20}$ eV) would lead
dynamically to both new non-black hole compact objects (bosonic stars) and new
non-Kerr black holes, with masses of $\sim M_\odot$ to $\sim 10^{10} M_\odot$,
corresponding to the mass range of astrophysical black hole candidates (from
stellar mass to supermassive). For each model, we study the properties of the
mass spectrum and interactions after spontaneous symmetry breaking, discuss its
theoretical viability and caveats, as well as some of its potential and most
relevant phenomenological implications {linking them to the} physics of compact
objects.
|
[
{
"created": "Tue, 20 Jul 2021 13:42:40 GMT",
"version": "v1"
},
{
"created": "Sun, 19 Dec 2021 12:04:32 GMT",
"version": "v2"
}
] |
2022-01-05
|
[
[
"Freitas",
"Felipe F.",
""
],
[
"Herdeiro",
"Carlos A. R.",
""
],
[
"Morais",
"António P.",
""
],
[
"Onofre",
"António",
""
],
[
"Pasechnik",
"Roman",
""
],
[
"Radu",
"Eugen",
""
],
[
"Sanchis-Gual",
"Nicolas",
""
],
[
"Santos",
"Rui",
""
]
] |
We construct families, and concrete examples, of simple extensions of the Standard Model that can yield ultralight {real or} complex vectors or scalars with potential astrophysical relevance. Specifically, the mass range for these putative fundamental bosons ($\sim 10^{-10}-10^{-20}$ eV) would lead dynamically to both new non-black hole compact objects (bosonic stars) and new non-Kerr black holes, with masses of $\sim M_\odot$ to $\sim 10^{10} M_\odot$, corresponding to the mass range of astrophysical black hole candidates (from stellar mass to supermassive). For each model, we study the properties of the mass spectrum and interactions after spontaneous symmetry breaking, discuss its theoretical viability and caveats, as well as some of its potential and most relevant phenomenological implications {linking them to the} physics of compact objects.
|
1209.6403
|
Alexander Kusenko
|
Alexander Kusenko, Michael Loewenstein, Tsutomu T. Yanagida
|
Moduli dark matter and the search for its decay line using Suzaku X-ray
telescope
|
8 pages, 5 figures, revtex
|
Phys. Rev. D 87, 043508 (2013)
|
10.1103/PhysRevD.87.043508
|
IPMU12-0180
|
hep-ph astro-ph.CO hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Light scalar fields called moduli arise from a variety of different models
involving supersymmetry and/or string theory; thus their existence is a generic
prediction of leading theories for physics beyond the standard model. They also
present a formidable, long-standing problem for cosmology. We argue that an
anthropic solution to the moduli problem exists in the case of small moduli
masses, and that it automatically leads to dark matter in the form of moduli.
The recent discovery of the 125 GeV Higgs boson implies a lower bound on the
moduli mass of about a keV. This form of dark matter is consistent with the
observed properties of structure formation, and it is amenable to detection
with the help of X-ray telescopes. We present the results of a search for such
dark matter particles using spectra extracted from the first deep X-ray
observations of the Draco and Ursa Minor dwarf spheroidal galaxies, which are
dark matter dominated systems with extreme mass-to-light ratios and low
intrinsic backgrounds. No emission line is positively detected, and we set new
constraints on the relevant new physics.
|
[
{
"created": "Fri, 28 Sep 2012 01:07:47 GMT",
"version": "v1"
},
{
"created": "Fri, 3 May 2013 22:53:31 GMT",
"version": "v2"
}
] |
2013-05-07
|
[
[
"Kusenko",
"Alexander",
""
],
[
"Loewenstein",
"Michael",
""
],
[
"Yanagida",
"Tsutomu T.",
""
]
] |
Light scalar fields called moduli arise from a variety of different models involving supersymmetry and/or string theory; thus their existence is a generic prediction of leading theories for physics beyond the standard model. They also present a formidable, long-standing problem for cosmology. We argue that an anthropic solution to the moduli problem exists in the case of small moduli masses, and that it automatically leads to dark matter in the form of moduli. The recent discovery of the 125 GeV Higgs boson implies a lower bound on the moduli mass of about a keV. This form of dark matter is consistent with the observed properties of structure formation, and it is amenable to detection with the help of X-ray telescopes. We present the results of a search for such dark matter particles using spectra extracted from the first deep X-ray observations of the Draco and Ursa Minor dwarf spheroidal galaxies, which are dark matter dominated systems with extreme mass-to-light ratios and low intrinsic backgrounds. No emission line is positively detected, and we set new constraints on the relevant new physics.
|
1905.04865
|
Jun Gao
|
Jun Gao
|
Higgs boson decay into four bottom quarks in the SM and beyond
|
references added; version to appear on JHEP
| null |
10.1007/JHEP08(2019)174
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We present predictions for the Higgs boson decay into four bottom quarks in
the standard model and via light exotic scalars retaining full bottom-quark
mass dependence. In the SM the decay can be induced either by the Yukawa
couplings of bottom quarks and top quarks or the electroweak couplings. We
calculate the partial decay width and various differential distributions up to
next-to-leading order in QCD. We find large QCD corrections for decay via
Yukawa couplings, as large as 90% for the partial decay width, and reduced
scale variations. The results of this paper are therefore helpful for the
measurement of this multi-jets final state at future Higgs factory of
electron-positron colliders. We also propose several observables that can
differentiate the SM decay channel and the exotic decay channel and compare
their next-to-leading order predictions.
|
[
{
"created": "Mon, 13 May 2019 05:22:45 GMT",
"version": "v1"
},
{
"created": "Fri, 17 May 2019 13:50:39 GMT",
"version": "v2"
},
{
"created": "Tue, 3 Sep 2019 05:51:34 GMT",
"version": "v3"
}
] |
2019-10-02
|
[
[
"Gao",
"Jun",
""
]
] |
We present predictions for the Higgs boson decay into four bottom quarks in the standard model and via light exotic scalars retaining full bottom-quark mass dependence. In the SM the decay can be induced either by the Yukawa couplings of bottom quarks and top quarks or the electroweak couplings. We calculate the partial decay width and various differential distributions up to next-to-leading order in QCD. We find large QCD corrections for decay via Yukawa couplings, as large as 90% for the partial decay width, and reduced scale variations. The results of this paper are therefore helpful for the measurement of this multi-jets final state at future Higgs factory of electron-positron colliders. We also propose several observables that can differentiate the SM decay channel and the exotic decay channel and compare their next-to-leading order predictions.
|
hep-ph/0111328
|
George Lazarides
|
G. Lazarides (Aristotle University of Thessaloniki)
|
Inflationary Cosmology
|
40 pages; uses svmult.cls, physprbb.sty, subeqnar.sty, cropmark.sty,
sprmindx.sty; minor corrections; lectures given at the "First Aegean Summer
School on Cosmology", September 21-29 2001, Karlovassi, Samos, Greece (to
appear in the proceedings)
|
Lect.NotesPhys.592:351-391,2002
| null |
UT-STPD-3-01
|
hep-ph
| null |
The big bang model and the history of the early universe according to the
grand unified theories are introduced. The shortcomings of big bang are
discussed together with their resolution by inflationary cosmology. Inflation,
the subsequent oscillation and decay of the inflaton, and the resulting
"reheating" of the universe are studied. The density perturbations produced by
inflation and the temperature fluctuations of the cosmic background radiation
are discussed. The hybrid inflationary model is described. Two "natural"
extensions of this model which avoid the disaster encountered in its standard
realization from the overproduction of monopoles are presented. Successful
"reheating" satisfying the gravitino constraint takes place after the end of
inflation in all three versions of hybrid inflation. Adequate baryogenesis via
a primordial leptogenesis occurs consistently with the solar and atmospheric
neutrino oscillation data. The primordial lepton asymmetry is turned partly
into baryon asymmetry via the sphalerons which are summarized.
|
[
{
"created": "Mon, 26 Nov 2001 10:35:50 GMT",
"version": "v1"
},
{
"created": "Fri, 26 Apr 2002 08:12:29 GMT",
"version": "v2"
}
] |
2008-11-26
|
[
[
"Lazarides",
"G.",
"",
"Aristotle University of Thessaloniki"
]
] |
The big bang model and the history of the early universe according to the grand unified theories are introduced. The shortcomings of big bang are discussed together with their resolution by inflationary cosmology. Inflation, the subsequent oscillation and decay of the inflaton, and the resulting "reheating" of the universe are studied. The density perturbations produced by inflation and the temperature fluctuations of the cosmic background radiation are discussed. The hybrid inflationary model is described. Two "natural" extensions of this model which avoid the disaster encountered in its standard realization from the overproduction of monopoles are presented. Successful "reheating" satisfying the gravitino constraint takes place after the end of inflation in all three versions of hybrid inflation. Adequate baryogenesis via a primordial leptogenesis occurs consistently with the solar and atmospheric neutrino oscillation data. The primordial lepton asymmetry is turned partly into baryon asymmetry via the sphalerons which are summarized.
|
2406.01678
|
Mudit Jain
|
Mudit Jain, Angelo Maggi, Wen-Yuan Ai, David J.E. Marsh
|
New insights into axion freeze-in
|
18 pages, 10 figures, 3 appendices
| null | null |
KCL-PH-TH/2024-31
|
hep-ph astro-ph.CO hep-th
|
http://creativecommons.org/licenses/by/4.0/
|
Freeze-in via the axion-photon coupling, $g_{\phi\gamma}$, can produce axions
in the early Universe. At low reheating temperatures close to the minimum
allowed value $T_{\rm reh}\approx T_{\rm BBN}\approx 10\,{\rm MeV}$, the
abundance peaks for axion masses $m_\phi\approx T_{\rm reh}$. Such heavy axions
are unstable and subsequently decay, leading to strong constraints on
$g_{\phi\gamma}$ from astrophysics and cosmology. In this work, we revisit the
computation of the freeze-in abundance and clarify important issues. We begin
with a complete computation of the collision terms for the Primakoff process,
electron-positron annihilation, and photon-to-axion (inverse-)decay, while
approximately taking into account plasma screening and threshold effects. We
then solve the Boltzmann equation for the full axion distribution function. We
confirm previous results about the importance of both processes to the
effective "relic abundance" (defined as density prior to decay), and provide
useful fitting formulae to estimate the freeze-in abundance from the
equilibrium interaction rate. For the distribution function, we find an
out-of-equilibrium population of axions and introduce an effective temperature
for them. We follow the evolution right up until decay, and find that the
average axion kinetic energy is larger than a thermal relic by between 20\% and
80\%, which may have implications for limits on decaying axions from X-ray
spectra. We extend our study to a two-axion system with quartic cross-coupling,
and find that for typical/expected couplings, freeze-in of a second axion
flavour by annihilations leads to a negligibly small contribution to the relic
density.
|
[
{
"created": "Mon, 3 Jun 2024 18:00:01 GMT",
"version": "v1"
}
] |
2024-06-05
|
[
[
"Jain",
"Mudit",
""
],
[
"Maggi",
"Angelo",
""
],
[
"Ai",
"Wen-Yuan",
""
],
[
"Marsh",
"David J. E.",
""
]
] |
Freeze-in via the axion-photon coupling, $g_{\phi\gamma}$, can produce axions in the early Universe. At low reheating temperatures close to the minimum allowed value $T_{\rm reh}\approx T_{\rm BBN}\approx 10\,{\rm MeV}$, the abundance peaks for axion masses $m_\phi\approx T_{\rm reh}$. Such heavy axions are unstable and subsequently decay, leading to strong constraints on $g_{\phi\gamma}$ from astrophysics and cosmology. In this work, we revisit the computation of the freeze-in abundance and clarify important issues. We begin with a complete computation of the collision terms for the Primakoff process, electron-positron annihilation, and photon-to-axion (inverse-)decay, while approximately taking into account plasma screening and threshold effects. We then solve the Boltzmann equation for the full axion distribution function. We confirm previous results about the importance of both processes to the effective "relic abundance" (defined as density prior to decay), and provide useful fitting formulae to estimate the freeze-in abundance from the equilibrium interaction rate. For the distribution function, we find an out-of-equilibrium population of axions and introduce an effective temperature for them. We follow the evolution right up until decay, and find that the average axion kinetic energy is larger than a thermal relic by between 20\% and 80\%, which may have implications for limits on decaying axions from X-ray spectra. We extend our study to a two-axion system with quartic cross-coupling, and find that for typical/expected couplings, freeze-in of a second axion flavour by annihilations leads to a negligibly small contribution to the relic density.
|
hep-ph/0701033
|
Jens O. Andersen
|
Jens O. Andersen and Lars Kyllingstad
|
Pion Condensation in a two-flavor NJL model: the role of charge
neutrality
|
16 pages. 13 figs. Second version expanded significantly: Discussion
and results now include finite quark masses as well as comparison with other
approaches. More appropriate title. Third version matches published paper
|
J. Phys. G: Nucl. Part. Phys. 37 015003 (2010)
| null | null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We study pion condensation and the phase structure in a two-flavor
Nambu-Jona-Lasinio model in the presence of baryon chemical potential $\mu$ and
isospin chemical potential $\mu_I$at zero and finite temperature. There is a
competition between the chiral condensate and a Bose-Einstein condensate of
charged pions. In the chiral limit, the chiral condensate vanishes for any
finite value of the isospin chemical potential, while there is a charged pion
condensate that depends on the chemical potentials and the temperature. At the
physical point, the chiral condensate is always nonzero, while the charged pion
condensate depends on $\mu_I$ and $T$. For $T=\mu=0$, the critical isospin
chemical potential $\mu_I^c$ for the onset of Bose-Einstein condensation is
always equal to the pion mass. For $\mu=0$, we compare our results with chiral
perturbation theory, sigma-model calculations, and lattice simulations. We
examine the effects of imposing electric charge neutrality and weak equilibrium
on the phase structure of the model. In the chiral limit, there is a window of
baryon chemical potential and temperature where the charged pions condense. At
the physical point, the charged pions do not condense.
|
[
{
"created": "Thu, 4 Jan 2007 20:00:26 GMT",
"version": "v1"
},
{
"created": "Thu, 22 Jan 2009 13:54:16 GMT",
"version": "v2"
},
{
"created": "Wed, 2 Dec 2009 08:16:12 GMT",
"version": "v3"
}
] |
2009-12-02
|
[
[
"Andersen",
"Jens O.",
""
],
[
"Kyllingstad",
"Lars",
""
]
] |
We study pion condensation and the phase structure in a two-flavor Nambu-Jona-Lasinio model in the presence of baryon chemical potential $\mu$ and isospin chemical potential $\mu_I$at zero and finite temperature. There is a competition between the chiral condensate and a Bose-Einstein condensate of charged pions. In the chiral limit, the chiral condensate vanishes for any finite value of the isospin chemical potential, while there is a charged pion condensate that depends on the chemical potentials and the temperature. At the physical point, the chiral condensate is always nonzero, while the charged pion condensate depends on $\mu_I$ and $T$. For $T=\mu=0$, the critical isospin chemical potential $\mu_I^c$ for the onset of Bose-Einstein condensation is always equal to the pion mass. For $\mu=0$, we compare our results with chiral perturbation theory, sigma-model calculations, and lattice simulations. We examine the effects of imposing electric charge neutrality and weak equilibrium on the phase structure of the model. In the chiral limit, there is a window of baryon chemical potential and temperature where the charged pions condense. At the physical point, the charged pions do not condense.
|
2111.14891
|
Avi Loeb
|
Abraham Loeb
|
A New Way to Limit the Interaction of Dark Matter with Baryons
|
Submitted to Physical Review Letters
|
Physical Review D, 105, 9 (2022)
|
10.1103/PhysRevD.105.L091903
| null |
hep-ph astro-ph.CO hep-ex
|
http://creativecommons.org/licenses/by/4.0/
|
Recently, there had been renewed interest in limiting the interaction between
dark matter particles and known particles. I propose a new way to set upper
limits on the coupling of ions or electrons to dark matter particles of
arbitrary mass, based on Faraday's Law in a spinning conductor.
|
[
{
"created": "Mon, 29 Nov 2021 19:02:13 GMT",
"version": "v1"
},
{
"created": "Wed, 1 Dec 2021 10:37:20 GMT",
"version": "v2"
},
{
"created": "Fri, 11 Feb 2022 15:34:17 GMT",
"version": "v3"
}
] |
2022-08-29
|
[
[
"Loeb",
"Abraham",
""
]
] |
Recently, there had been renewed interest in limiting the interaction between dark matter particles and known particles. I propose a new way to set upper limits on the coupling of ions or electrons to dark matter particles of arbitrary mass, based on Faraday's Law in a spinning conductor.
|
1807.08167
|
Nabarun Chakrabarty
|
Nabarun Chakrabarty, Cheng-Wei Chiang, Takahiro Ohata, Koji Tsumura
|
Charged scalars confronting neutrino mass and muon g-2 anomaly
|
4 tables, 14 captioned figures
| null |
10.1007/JHEP12(2018)104
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The present work introduces two possible extensions of the Standard Model
Higgs sector. In the first case, the Zee-Babu type model for the generation of
neutrino mass is augmented with a scalar triplet and additional singly charged
scalar singlets. The second scenario, on the other hand, generalizes the
Type-II seesaw model by replicating the number of the scalar triplets. A
$\mathbb{Z}_3$ symmetry is imposed in case of both the scenarios, but, allowed
to be violated by terms of mass dimension two and three for generating neutrino
masses and mixings. We examine how the models so introduced can explain the
experimental observation on the muon anomalous magnetic moment. We estimate the
two-loop contribution to neutrino mass induced by the scalar triplet, in
addition to what comes from the doubly charged singlet in the usual Zee-Babu
framework, in the first model. On the other hand, the neutrino mass arises in
the usual Type-II fashion in the second model. In addition, the role of the
$\mathbb{Z}_3$ symmetry in suppressing lepton flavor violation is also
elucidated.
|
[
{
"created": "Sat, 21 Jul 2018 15:19:29 GMT",
"version": "v1"
}
] |
2019-01-30
|
[
[
"Chakrabarty",
"Nabarun",
""
],
[
"Chiang",
"Cheng-Wei",
""
],
[
"Ohata",
"Takahiro",
""
],
[
"Tsumura",
"Koji",
""
]
] |
The present work introduces two possible extensions of the Standard Model Higgs sector. In the first case, the Zee-Babu type model for the generation of neutrino mass is augmented with a scalar triplet and additional singly charged scalar singlets. The second scenario, on the other hand, generalizes the Type-II seesaw model by replicating the number of the scalar triplets. A $\mathbb{Z}_3$ symmetry is imposed in case of both the scenarios, but, allowed to be violated by terms of mass dimension two and three for generating neutrino masses and mixings. We examine how the models so introduced can explain the experimental observation on the muon anomalous magnetic moment. We estimate the two-loop contribution to neutrino mass induced by the scalar triplet, in addition to what comes from the doubly charged singlet in the usual Zee-Babu framework, in the first model. On the other hand, the neutrino mass arises in the usual Type-II fashion in the second model. In addition, the role of the $\mathbb{Z}_3$ symmetry in suppressing lepton flavor violation is also elucidated.
|
1208.4104
|
Susanne Westhoff
|
Stefan Berge and Susanne Westhoff
|
Top-Quark Charge Asymmetry with a Jet Handle
|
29 pages, 12 figures
| null |
10.1103/PhysRevD.86.094036
| null |
hep-ph hep-ex
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Pairs of top and antitop quarks are produced at the LHC to a large extent in
association with a hard jet. We investigate the charge asymmetry in top pair +
jet production in quantum chromodynamics (QCD) and with additional massive
color-octet vector bosons. The total charge asymmetry at the LHC is suppressed
by the large charge-symmetric background from gluon-gluon fusion. We show to
what extent the asymmetry can be enhanced by suitable phase space cuts and, in
particular, elaborate on the kinematics of the hard jet in the top pair + jet
final state. We demonstrate that in QCD, the asymmetry amounts to -1.5% for
central jets without an excessive reduction of the cross section. By applying
additional kinematical cuts, the asymmetry can be enhanced to -4%, but at the
cost of a strong reduction of the cross section. Massive color-octet states can
generate sizeable effects in top pair + jet production, both on the charge
asymmetry and on the cross section. The charge asymmetry probes both vector and
axial-vector couplings to quarks. We show that massive color octets can
generate asymmetries up to +-10% for moderate and up to +-30% for strong
kinematical cuts to be used in experimental analyses at the LHC. Jet kinematics
can be used to obtain further information about the nature of the couplings and
thereby to discriminate between different models.
|
[
{
"created": "Mon, 20 Aug 2012 20:00:02 GMT",
"version": "v1"
},
{
"created": "Fri, 9 Nov 2012 14:15:00 GMT",
"version": "v2"
}
] |
2013-05-30
|
[
[
"Berge",
"Stefan",
""
],
[
"Westhoff",
"Susanne",
""
]
] |
Pairs of top and antitop quarks are produced at the LHC to a large extent in association with a hard jet. We investigate the charge asymmetry in top pair + jet production in quantum chromodynamics (QCD) and with additional massive color-octet vector bosons. The total charge asymmetry at the LHC is suppressed by the large charge-symmetric background from gluon-gluon fusion. We show to what extent the asymmetry can be enhanced by suitable phase space cuts and, in particular, elaborate on the kinematics of the hard jet in the top pair + jet final state. We demonstrate that in QCD, the asymmetry amounts to -1.5% for central jets without an excessive reduction of the cross section. By applying additional kinematical cuts, the asymmetry can be enhanced to -4%, but at the cost of a strong reduction of the cross section. Massive color-octet states can generate sizeable effects in top pair + jet production, both on the charge asymmetry and on the cross section. The charge asymmetry probes both vector and axial-vector couplings to quarks. We show that massive color octets can generate asymmetries up to +-10% for moderate and up to +-30% for strong kinematical cuts to be used in experimental analyses at the LHC. Jet kinematics can be used to obtain further information about the nature of the couplings and thereby to discriminate between different models.
|
1608.08205
|
Oleksii Gryniuk
|
Oleksii Gryniuk and Marc Vanderhaeghen
|
Accessing the real part of the forward $J/\psi$-p scattering amplitude
from $J/\psi$ photo-production on protons around threshold
| null |
Phys. Rev. D 94, 074001 (2016)
|
10.1103/PhysRevD.94.074001
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We provide an updated analysis of the forward $J/\psi$-p scattering
amplitude, relating its imaginary part to $\gamma p \to J/\psi p$ and $\gamma p
\to c \bar c X$ cross section data, and calculating its real part through a
once-subtracted dispersion relation. From a global fit to both differential and
total cross section data, we extract a value for the spin-averaged $J/\psi$-p
s-wave scattering length $a_{\psi p} = 0.046 \pm 0.005$ fm, which can be
translated into a $J/\psi$ binding energy in nuclear matter of $B_\psi = 2.7
\pm 0.3$ MeV. We estimate the forward-backward asymmetry to the $\gamma p \to
e^- e^+ p$ process around the $J/\psi$ resonance, which results from
interchanging the leptons in the interference between the $J/\psi$ production
and the Bethe-Heitler mechanisms. We show that to good approximation this
asymmetry depends linearly on $a_{\psi p}$, and can reach values around -25%
for forthcoming $J/\psi$ threshold production experiments at Jefferson Lab. Its
measurement can thus provide a very sensitive observable for a refined
extraction of $a_{\psi p}$.
|
[
{
"created": "Mon, 29 Aug 2016 19:58:16 GMT",
"version": "v1"
}
] |
2016-10-12
|
[
[
"Gryniuk",
"Oleksii",
""
],
[
"Vanderhaeghen",
"Marc",
""
]
] |
We provide an updated analysis of the forward $J/\psi$-p scattering amplitude, relating its imaginary part to $\gamma p \to J/\psi p$ and $\gamma p \to c \bar c X$ cross section data, and calculating its real part through a once-subtracted dispersion relation. From a global fit to both differential and total cross section data, we extract a value for the spin-averaged $J/\psi$-p s-wave scattering length $a_{\psi p} = 0.046 \pm 0.005$ fm, which can be translated into a $J/\psi$ binding energy in nuclear matter of $B_\psi = 2.7 \pm 0.3$ MeV. We estimate the forward-backward asymmetry to the $\gamma p \to e^- e^+ p$ process around the $J/\psi$ resonance, which results from interchanging the leptons in the interference between the $J/\psi$ production and the Bethe-Heitler mechanisms. We show that to good approximation this asymmetry depends linearly on $a_{\psi p}$, and can reach values around -25% for forthcoming $J/\psi$ threshold production experiments at Jefferson Lab. Its measurement can thus provide a very sensitive observable for a refined extraction of $a_{\psi p}$.
|
1106.5739
|
Claude Duhr
|
Stephan Buehler, Claude Duhr
|
CHAPLIN - Complex Harmonic Polylogarithms in Fortran
|
29 pages, 1 figure, 5 tables
| null | null |
IPPP/11/36, DCPT/11/72
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We present a new Fortran library to evaluate all harmonic polylogarithms up
to weight four numerically for any complex argument. The algorithm is based on
a reduction of harmonic polylogarithms up to weight four to a minimal set of
basis functions that are computed numerically using series expansions allowing
for fast and reliable numerical results.
|
[
{
"created": "Tue, 28 Jun 2011 17:43:07 GMT",
"version": "v1"
}
] |
2011-06-29
|
[
[
"Buehler",
"Stephan",
""
],
[
"Duhr",
"Claude",
""
]
] |
We present a new Fortran library to evaluate all harmonic polylogarithms up to weight four numerically for any complex argument. The algorithm is based on a reduction of harmonic polylogarithms up to weight four to a minimal set of basis functions that are computed numerically using series expansions allowing for fast and reliable numerical results.
|
hep-ph/0612032
|
Makoto Sakaguchi
|
Holger B. Nielsen and Masao Ninomiya
|
Future Dependent Initial Conditions from Imaginary Part in Lagrangian
|
48 pages
| null | null |
YITP-06-62, OIQP-06-18
|
hep-ph hep-th
| null |
We want to unify usual equation of motion laws of nature with "laws" about
initial conditions, second law of thermodynamics, cosmology. By introducing an
imaginary part -- of a similar form but different parameters as the usual real
part -- for the action to be used in the Feynmann path way integral we obtain a
model determining (not only equations of motion but) also the initial
conditions, for say a quantum field theory. We set up the formalism for e.g.
expectation values, classical approximation in such a model and show that
provided the imaginary part gets unimportant except in the Big Bang era the
model can match the usual theory. Speculatively requiring that there be place
for Dirac strings and thus in principle monopoles in the model we can push away
the effects of the imaginary part to be involved only with particles not yet
found. Most promising for seeing the initial condition determining effects from
the imaginary part is thus the Higgs particle. We predict that the width of the
Higgs particle shall likely turn out to be (appreciably perhaps) broader than
calculated by summing usual decay rates. Higgs machines will be hit by bad
luck.
|
[
{
"created": "Tue, 5 Dec 2006 00:53:20 GMT",
"version": "v1"
},
{
"created": "Thu, 7 Dec 2006 09:14:23 GMT",
"version": "v2"
}
] |
2007-05-23
|
[
[
"Nielsen",
"Holger B.",
""
],
[
"Ninomiya",
"Masao",
""
]
] |
We want to unify usual equation of motion laws of nature with "laws" about initial conditions, second law of thermodynamics, cosmology. By introducing an imaginary part -- of a similar form but different parameters as the usual real part -- for the action to be used in the Feynmann path way integral we obtain a model determining (not only equations of motion but) also the initial conditions, for say a quantum field theory. We set up the formalism for e.g. expectation values, classical approximation in such a model and show that provided the imaginary part gets unimportant except in the Big Bang era the model can match the usual theory. Speculatively requiring that there be place for Dirac strings and thus in principle monopoles in the model we can push away the effects of the imaginary part to be involved only with particles not yet found. Most promising for seeing the initial condition determining effects from the imaginary part is thus the Higgs particle. We predict that the width of the Higgs particle shall likely turn out to be (appreciably perhaps) broader than calculated by summing usual decay rates. Higgs machines will be hit by bad luck.
|
1602.05514
|
John Gracey
|
J.M. Bell, J.A. Gracey
|
Bilinear quark operator renormalization at generalized symmetric point
|
19 latex pages, 4 figures, anc directory contains electronic version
of amplitudes
|
Phys. Rev. D 93, 065031 (2016)
|
10.1103/PhysRevD.93.065031
|
LTH 1077
|
hep-ph hep-lat
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We compute Green's functions with a bilinear quark operator inserted at
non-zero momentum for a generalized momentum configuration to two loops. These
are required to assist lattice gauge theory measurements of the same quantity
in matching to the high energy behaviour. The flavour non-singlet operators
considered are the scalar, vector and tensor currents as well as the second
moment of the twist-2 Wilson operator used in deep inelastic scattering for the
measurement of nucleon structure functions.
|
[
{
"created": "Wed, 17 Feb 2016 18:03:11 GMT",
"version": "v1"
}
] |
2016-03-30
|
[
[
"Bell",
"J. M.",
""
],
[
"Gracey",
"J. A.",
""
]
] |
We compute Green's functions with a bilinear quark operator inserted at non-zero momentum for a generalized momentum configuration to two loops. These are required to assist lattice gauge theory measurements of the same quantity in matching to the high energy behaviour. The flavour non-singlet operators considered are the scalar, vector and tensor currents as well as the second moment of the twist-2 Wilson operator used in deep inelastic scattering for the measurement of nucleon structure functions.
|
hep-ph/0007116
|
Ian D. Lawrie
|
I. D. Lawrie and D. B. McKernan
|
Nonequilibrium perturbation theory for spin-1/2 fields
|
16 pages; no figures; submitted to Phys. Rev. D
|
Phys.Rev. D62 (2000) 105032
|
10.1103/PhysRevD.62.105032
| null |
hep-ph gr-qc hep-th
| null |
A partial resummation of perturbation theory is described for field theories
containing spin-1/2 particles in states that may be far from thermal
equilibrium. This allows the nonequilibrium state to be characterized in terms
of quasiparticles that approximate its true elementary excitations. In
particular, the quasiparticles have dispersion relations that differ from those
of free particles, finite thermal widths and occupation numbers which, in
contrast to those of standard perturbation theory evolve with the changing
nonequilibrium environment. A description of this kind is essential for
estimating the evolution of the system over extended periods of time. In
contrast to the corresponding description of scalar particles, the structure of
nonequilibrium fermion propagators exhibits features which have no counterpart
in the equilibrium theory.
|
[
{
"created": "Wed, 12 Jul 2000 13:56:24 GMT",
"version": "v1"
}
] |
2009-10-31
|
[
[
"Lawrie",
"I. D.",
""
],
[
"McKernan",
"D. B.",
""
]
] |
A partial resummation of perturbation theory is described for field theories containing spin-1/2 particles in states that may be far from thermal equilibrium. This allows the nonequilibrium state to be characterized in terms of quasiparticles that approximate its true elementary excitations. In particular, the quasiparticles have dispersion relations that differ from those of free particles, finite thermal widths and occupation numbers which, in contrast to those of standard perturbation theory evolve with the changing nonequilibrium environment. A description of this kind is essential for estimating the evolution of the system over extended periods of time. In contrast to the corresponding description of scalar particles, the structure of nonequilibrium fermion propagators exhibits features which have no counterpart in the equilibrium theory.
|
1704.02615
|
Michio Hashimoto
|
Michio Hashimoto
|
Revisiting Vector-like Quark Model with Enhanced Top Yukawa Coupling
|
21 pages, 1 table, 6 figures. Discussions of Sec.III are extended.
References added. version published in PRD
|
Phys. Rev. D 96, 035020 (2017)
|
10.1103/PhysRevD.96.035020
| null |
hep-ph hep-ex
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We revisit a scenario with an enhanced top yukawa coupling in vector-like
quark (VLQ) models, where the top yukawa coupling is larger than the standard
model value and the lightest VLQ has a negative yukawa coupling. We find that
the parameter space satisfying the LHC bounds of the Higgs signal strengths
consistently with the precision measurements is rather wide. Because the
Lagrangian parameters of the yukawa couplings are large, such scenario can be
realized in some strongly interacting theories. It also turns out that there is
a noticeable relation between the contributions of the triangle and box
diagrams in the $gg \to hh$ process by using the lowest order of the $1/M$
expansion where $M$ is the heavy mass running in the loops.
|
[
{
"created": "Sun, 9 Apr 2017 15:09:59 GMT",
"version": "v1"
},
{
"created": "Mon, 17 Apr 2017 11:07:20 GMT",
"version": "v2"
},
{
"created": "Thu, 3 Aug 2017 12:00:18 GMT",
"version": "v3"
}
] |
2017-08-30
|
[
[
"Hashimoto",
"Michio",
""
]
] |
We revisit a scenario with an enhanced top yukawa coupling in vector-like quark (VLQ) models, where the top yukawa coupling is larger than the standard model value and the lightest VLQ has a negative yukawa coupling. We find that the parameter space satisfying the LHC bounds of the Higgs signal strengths consistently with the precision measurements is rather wide. Because the Lagrangian parameters of the yukawa couplings are large, such scenario can be realized in some strongly interacting theories. It also turns out that there is a noticeable relation between the contributions of the triangle and box diagrams in the $gg \to hh$ process by using the lowest order of the $1/M$ expansion where $M$ is the heavy mass running in the loops.
|
2210.09272
|
Wan-Li Ju
|
Wan-Li Ju, Marek Sch\"onherr
|
Projected transverse momentum resummation in top-antitop pair production
at LHC
| null |
JHEP02(2023)075
|
10.1007/JHEP02(2023)075
|
IPPP/22/73 MCnet-22-20
|
hep-ph
|
http://creativecommons.org/licenses/by/4.0/
|
The transverse momentum distribution of the $t\bar{t}$ system is of both
experimental and theoretical interest. In the presence of the azimuthally
asymmetric divergences, pursuing the resummation at the high logarithmic
precision is rather demanding in general. In this paper, we propose the
projected transverse momentum spectrum $\mathrm{d}\sigma_{t\bar{t}}/\mathrm{d}
q_{\tau}$, which is derived from the classical $\vec{q}_{\mathrm{T}}$ spectrum
by integrating out the rejection component $q_{\tau_{\perp}}$ with respect to a
reference unit vector $\vec{\tau}$, to serve as an alternative resolution to
curb those asymmetric influences, in additional to the azimuthally averaged
case $\mathrm{d}\sigma_{t\bar{t}}/\mathrm{d} |\vec{q}_{\mathrm{T}}|$. In the
context of the effective field theories, SCET$_{\mathrm{II}}$ and HQET, we will
demonstrate that in spite of the $q_{\tau_{\perp}}$ integrations, the leading
asymptotic terms of $\mathrm{d}\sigma_{t\bar{t}}/\mathrm{d} q_{\tau}$ still
observe the factorization pattern in terms of the hard, beam, and soft
functions in the vicinity of $ q_{\tau}=0$~GeV. With the help of the
renormalisation group equation techniques, we evaluate the resummed spectra
$\mathrm{d}\sigma_{t\bar{t}}/\mathrm{d} q_{\mathrm{T,in}}$,
$\mathrm{d}\sigma_{t\bar{t}}/\mathrm{d} q_{\mathrm{T,out}}$, and
$\mathrm{d}\sigma_{t\bar{t}}/\mathrm{d} \Delta\Phi_{t\bar{t}}$ at NLL+NLO,
NNLL+NNLO, and approximate NNLL'+NNLO accuracy. This is the first time the
azimuthal spectrum $\Delta\Phi_{t\bar{t}}$ is appraised at or beyond the NNLL
level including a consistent treatment of both beam collinear and soft
radiation.
|
[
{
"created": "Mon, 17 Oct 2022 17:22:06 GMT",
"version": "v1"
},
{
"created": "Mon, 24 Oct 2022 11:49:02 GMT",
"version": "v2"
},
{
"created": "Sat, 11 Feb 2023 10:47:12 GMT",
"version": "v3"
}
] |
2023-02-14
|
[
[
"Ju",
"Wan-Li",
""
],
[
"Schönherr",
"Marek",
""
]
] |
The transverse momentum distribution of the $t\bar{t}$ system is of both experimental and theoretical interest. In the presence of the azimuthally asymmetric divergences, pursuing the resummation at the high logarithmic precision is rather demanding in general. In this paper, we propose the projected transverse momentum spectrum $\mathrm{d}\sigma_{t\bar{t}}/\mathrm{d} q_{\tau}$, which is derived from the classical $\vec{q}_{\mathrm{T}}$ spectrum by integrating out the rejection component $q_{\tau_{\perp}}$ with respect to a reference unit vector $\vec{\tau}$, to serve as an alternative resolution to curb those asymmetric influences, in additional to the azimuthally averaged case $\mathrm{d}\sigma_{t\bar{t}}/\mathrm{d} |\vec{q}_{\mathrm{T}}|$. In the context of the effective field theories, SCET$_{\mathrm{II}}$ and HQET, we will demonstrate that in spite of the $q_{\tau_{\perp}}$ integrations, the leading asymptotic terms of $\mathrm{d}\sigma_{t\bar{t}}/\mathrm{d} q_{\tau}$ still observe the factorization pattern in terms of the hard, beam, and soft functions in the vicinity of $ q_{\tau}=0$~GeV. With the help of the renormalisation group equation techniques, we evaluate the resummed spectra $\mathrm{d}\sigma_{t\bar{t}}/\mathrm{d} q_{\mathrm{T,in}}$, $\mathrm{d}\sigma_{t\bar{t}}/\mathrm{d} q_{\mathrm{T,out}}$, and $\mathrm{d}\sigma_{t\bar{t}}/\mathrm{d} \Delta\Phi_{t\bar{t}}$ at NLL+NLO, NNLL+NNLO, and approximate NNLL'+NNLO accuracy. This is the first time the azimuthal spectrum $\Delta\Phi_{t\bar{t}}$ is appraised at or beyond the NNLL level including a consistent treatment of both beam collinear and soft radiation.
|
hep-ph/9312255
|
Eletsky Vladimir
|
V.L. Eletsky and Ian I. Kogan
|
The Goldberger -- Treiman Relation, $g_A$ and $g_{\pi NN}$ at $T\neq 0$
|
7p, NSF-ITP-93-145, BUTP-93/27, PUTP-1433, November 1993
|
Phys.Rev.D49:3083-3086,1994
|
10.1103/PhysRevD.49.R3083
| null |
hep-ph nucl-th
| null |
The Goldberger-Treiman relation is shown to persist in the chiral limit at
finite temperatures to order $O(T^2)$. The $T$ dependence of $g_A$ turns out to
be the same as for $F_{\pi}$, $g_{A}(T)=g_{A}(0)(1-T^2/12F^2)$, while $g_{\pi
NN}$ is temperature independent to this order. The baryon octet ${\cal D}$ and
${\cal F}$ couplings also behave as $F_{\pi}$ if only pions are massless in the
pseudoscalar meson octet.
|
[
{
"created": "Fri, 10 Dec 1993 00:53:00 GMT",
"version": "v1"
}
] |
2009-12-30
|
[
[
"Eletsky",
"V. L.",
""
],
[
"Kogan",
"Ian I.",
""
]
] |
The Goldberger-Treiman relation is shown to persist in the chiral limit at finite temperatures to order $O(T^2)$. The $T$ dependence of $g_A$ turns out to be the same as for $F_{\pi}$, $g_{A}(T)=g_{A}(0)(1-T^2/12F^2)$, while $g_{\pi NN}$ is temperature independent to this order. The baryon octet ${\cal D}$ and ${\cal F}$ couplings also behave as $F_{\pi}$ if only pions are massless in the pseudoscalar meson octet.
|
hep-ph/0609134
|
Fulvia de Fazio
|
Fulvia De Fazio
|
Constraining Universal Extra Dimensions through B decays
|
Invited talk at "Continuous Advances in QCD 2006", May 11-14 2006,
Minneapolis (Minnesota). LaTex, 7 pages, 8 Figures
| null |
10.1142/9789812708267_0015
|
BARI-TH/541-06
|
hep-ph
| null |
We analyze the exclusive rare $B \to K^{(*)} \ell^+ \ell^-$, $B \to K^{(*)}
\nu \bar \nu$ and $B \to K^* \gamma$ decays in the Applequist-Cheng-Dobrescu
model, an extension of the Standard Model in presence of universal extra
dimensions. In the case of a single universal extra dimension, we study the
dependence of several observables on the compactification parameter 1/R, and
discuss whether the hadronic uncertainty due to the form factors obscures or
not such a dependence. We find that, using present data, it is possible in many
cases to put a sensible lower bound to 1/R, the most stringent one coming from
$B \to K^* \gamma$.
|
[
{
"created": "Thu, 14 Sep 2006 07:43:39 GMT",
"version": "v1"
}
] |
2017-08-23
|
[
[
"De Fazio",
"Fulvia",
""
]
] |
We analyze the exclusive rare $B \to K^{(*)} \ell^+ \ell^-$, $B \to K^{(*)} \nu \bar \nu$ and $B \to K^* \gamma$ decays in the Applequist-Cheng-Dobrescu model, an extension of the Standard Model in presence of universal extra dimensions. In the case of a single universal extra dimension, we study the dependence of several observables on the compactification parameter 1/R, and discuss whether the hadronic uncertainty due to the form factors obscures or not such a dependence. We find that, using present data, it is possible in many cases to put a sensible lower bound to 1/R, the most stringent one coming from $B \to K^* \gamma$.
|
2109.10377
|
Timea Vitos
|
Rikkert Frederix and Timea Vitos
|
The colour matrix at next-to-leading-colour accuracy for tree-level
multi-parton processes
|
36 pages, 6 figures, 10 tables
| null |
10.1007/JHEP12(2021)157
|
LU-TP 21-42
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We investigate the next-to-leading-colour (NLC) contributions to the colour
matrix in the fundamental and the colour-flow decompositions for tree-level
processes with all gluons, one quark pair and two quark pairs. By analytical
examination of the colour factors, we find the non-zero elements in the colour
matrix at NLC. At this colour order, together with the symmetry of the
phase-space, it is reduced from factorial to polynomial the scaling of the
contributing dual amplitudes as the number of partons participating in the
scattering process is increased. This opens a path to an accurate tree-level
matrix element generator of which all factorial complexity is removed, without
resulting to Monte Carlo sampling over colour.
|
[
{
"created": "Tue, 21 Sep 2021 18:01:21 GMT",
"version": "v1"
},
{
"created": "Fri, 5 Nov 2021 16:01:31 GMT",
"version": "v2"
}
] |
2022-01-05
|
[
[
"Frederix",
"Rikkert",
""
],
[
"Vitos",
"Timea",
""
]
] |
We investigate the next-to-leading-colour (NLC) contributions to the colour matrix in the fundamental and the colour-flow decompositions for tree-level processes with all gluons, one quark pair and two quark pairs. By analytical examination of the colour factors, we find the non-zero elements in the colour matrix at NLC. At this colour order, together with the symmetry of the phase-space, it is reduced from factorial to polynomial the scaling of the contributing dual amplitudes as the number of partons participating in the scattering process is increased. This opens a path to an accurate tree-level matrix element generator of which all factorial complexity is removed, without resulting to Monte Carlo sampling over colour.
|
hep-ph/0011026
|
Gerhard Ecker
|
G. Ecker
|
Strong interactions of light flavours
|
Lectures given at the Advanced School on QCD 2000, Benasque, Spain,
July 2000, to appear in the Proceedings; 25 pages, 3 figures
| null | null |
UWThPh-2000-43
|
hep-ph
| null |
After an introduction to chiral perturbation theory, the effective field
theory of the standard model at low energies, a brief overview is given of
applications to light-flavour physics. Three topics in the strong interactions
of pseudoscalar mesons are then discussed in some detail: loops and chiral
logs, pion-pion scattering and isospin violation.
|
[
{
"created": "Thu, 2 Nov 2000 10:22:01 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Ecker",
"G.",
""
]
] |
After an introduction to chiral perturbation theory, the effective field theory of the standard model at low energies, a brief overview is given of applications to light-flavour physics. Three topics in the strong interactions of pseudoscalar mesons are then discussed in some detail: loops and chiral logs, pion-pion scattering and isospin violation.
|
2408.08033
|
Kei Yagyu
|
Shinya Kanemura, Mariko Kikuchi, Kei Yagyu
|
New renormalization scheme in the two Higgs doublet models
|
22 pages, 4 figures
| null | null |
OU-HET-1239, NU-EHET 003
|
hep-ph
|
http://creativecommons.org/licenses/by/4.0/
|
We propose a new renormalization scheme in the two Higgs doublet models with
a softly-broken $Z_2$ symmetry and CP-conservation in the Higgs sector. In this
scheme, counterterms for mixing angles of the Higgs bosons are determined by
using the decay rates of the discovered Higgs boson $h$, $i.e.$, $h \to
\tau^+\tau^-$ and $h \to ZZ^* \to Z\ell^+\ell^-$ at next leading order (NLO)
instead of using the renormalized two-point functions which are adopted in the
previous scheme. We require that the decay rates at NLO are determined to be
the corresponding predictions at NLO in the Standard Model (SM) times square of
the scaling factor which describes the deviation of $h$ couplings at tree level
from the SM value. The mixing angles then maintain the meaning of the
``alignmentness", $i.e.$, how the properties of $h$ are close to the SM
predictions, while they lose such meaning in the previous scheme. We compare
the predictions of the decay rates at NLO given in the new scheme and those in
the previous scheme.
|
[
{
"created": "Thu, 15 Aug 2024 08:59:34 GMT",
"version": "v1"
}
] |
2024-08-16
|
[
[
"Kanemura",
"Shinya",
""
],
[
"Kikuchi",
"Mariko",
""
],
[
"Yagyu",
"Kei",
""
]
] |
We propose a new renormalization scheme in the two Higgs doublet models with a softly-broken $Z_2$ symmetry and CP-conservation in the Higgs sector. In this scheme, counterterms for mixing angles of the Higgs bosons are determined by using the decay rates of the discovered Higgs boson $h$, $i.e.$, $h \to \tau^+\tau^-$ and $h \to ZZ^* \to Z\ell^+\ell^-$ at next leading order (NLO) instead of using the renormalized two-point functions which are adopted in the previous scheme. We require that the decay rates at NLO are determined to be the corresponding predictions at NLO in the Standard Model (SM) times square of the scaling factor which describes the deviation of $h$ couplings at tree level from the SM value. The mixing angles then maintain the meaning of the ``alignmentness", $i.e.$, how the properties of $h$ are close to the SM predictions, while they lose such meaning in the previous scheme. We compare the predictions of the decay rates at NLO given in the new scheme and those in the previous scheme.
|
0906.1925
|
Bernd Kniehl
|
G. Cvetic, A.Yu. Illarionov, B.A. Kniehl, A.V. Kotikov
|
Small-x behavior of the structure function F_2 and its slope partial
ln(F_2)/partial ln(1/x) for "frozen" and analytic strong-coupling constants
|
new curves added to Figs. 1 and 2, minor changes to the text,
accepted for publication in Phys. Lett. B
|
Phys.Lett.B679:350-354,2009
|
10.1016/j.physletb.2009.07.057
|
DESY 09-086
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Using the leading-twist approximation of the Wilson operator product
expansion with "frozen" and analytic versions of the strong-coupling constant,
we show that the Bessel-inspired behavior of the structure function F_2 and its
slope\break partial ln(F_2)/partial ln(1/x) at small values of x, obtained for
a flat initial condition in the DGLAP evolution equations, leads to good
agreement with experimental data of deep-inelastic scattering at DESY HERA.
|
[
{
"created": "Wed, 10 Jun 2009 12:49:23 GMT",
"version": "v1"
},
{
"created": "Sat, 15 Aug 2009 11:16:09 GMT",
"version": "v2"
}
] |
2009-10-02
|
[
[
"Cvetic",
"G.",
""
],
[
"Illarionov",
"A. Yu.",
""
],
[
"Kniehl",
"B. A.",
""
],
[
"Kotikov",
"A. V.",
""
]
] |
Using the leading-twist approximation of the Wilson operator product expansion with "frozen" and analytic versions of the strong-coupling constant, we show that the Bessel-inspired behavior of the structure function F_2 and its slope\break partial ln(F_2)/partial ln(1/x) at small values of x, obtained for a flat initial condition in the DGLAP evolution equations, leads to good agreement with experimental data of deep-inelastic scattering at DESY HERA.
|
0903.0317
|
Roberto Iengo
|
R. Iengo (SISSA, Trieste)
|
Sommerfeld enhancement for a Yukawa potential
|
5 pages, figures showing the P wave resonance pattern added
| null | null | null |
hep-ph astro-ph.HE hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We show how easy it is to get the Sommerfeld enhancement for a Yukawa
potential, for definite partial waves, beyond the S wave analyzed in previous
literature. In particular, we report results for the P wave (for which there is
a resonant pattern and the enhancement can be of several orders of magnitude
even far from the resonance) that could be relevant for the analysis of
experimental cosmic rays data possibly signaling the annihilation of dark
matter particles.
|
[
{
"created": "Mon, 2 Mar 2009 17:19:08 GMT",
"version": "v1"
},
{
"created": "Thu, 19 Mar 2009 09:32:36 GMT",
"version": "v2"
}
] |
2009-03-19
|
[
[
"Iengo",
"R.",
"",
"SISSA, Trieste"
]
] |
We show how easy it is to get the Sommerfeld enhancement for a Yukawa potential, for definite partial waves, beyond the S wave analyzed in previous literature. In particular, we report results for the P wave (for which there is a resonant pattern and the enhancement can be of several orders of magnitude even far from the resonance) that could be relevant for the analysis of experimental cosmic rays data possibly signaling the annihilation of dark matter particles.
|
hep-ph/9812329
|
Gao Yanmin
|
Chen Gang, Liu Lianshou and Gao Yanmin
|
On the Factorial Moment Analysis of High Energy Experimental Data with
Non-integer Partition Number
|
18 pages 8 PS figures Record-No: HZPP-9811
|
Int.J.Mod.Phys. A14 (1999) 3687-3698
| null | null |
hep-ph
| null |
It is pointed out that in doing the factorial moment analysis with
non-integer partition $M$ of phase space, the influence of the phase-space
variation of two- (or more-) particle correlations has to be considered
carefully. In this paper this problem is studied and a systematic method is
developed to minimize this influence. The efficiency and self-consistency of
this method are shown using the data of 250 GeV/$c$ $\pi^+$p and K$^+$p
collisions from the NA22 experiment as example.
|
[
{
"created": "Fri, 11 Dec 1998 08:02:08 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Gang",
"Chen",
""
],
[
"Lianshou",
"Liu",
""
],
[
"Yanmin",
"Gao",
""
]
] |
It is pointed out that in doing the factorial moment analysis with non-integer partition $M$ of phase space, the influence of the phase-space variation of two- (or more-) particle correlations has to be considered carefully. In this paper this problem is studied and a systematic method is developed to minimize this influence. The efficiency and self-consistency of this method are shown using the data of 250 GeV/$c$ $\pi^+$p and K$^+$p collisions from the NA22 experiment as example.
|
hep-ph/0511213
|
Alexander Dolgov
|
A.D. Dolgov
|
CP violation in cosmology
|
Lectures presented at Varenna School "CP Violation: From Quarks to
Leptons", Varenna, Italy, July, 2005; a few references and discussion are
added
| null | null | null |
hep-ph
| null |
Cosmological implications of asymmetry between particles and antiparticles
are reviewed. Three possible mechanisms of CP-violation in cosmology are
described. General features of kinetics of generation of cosmological charge
asymmetry are discussed in detail. In particular, the cyclic balance condition,
which plays the same role in time non-invariant theory as detailed balance does
in T-invariant case, is derived. Several scenarios of baryogenesis are
described with an emphasis on CP-violation mechanisms. Production of cosmic
antimatter and a possibility of its ``living'' in our neighborhood is
discussed.
|
[
{
"created": "Thu, 17 Nov 2005 13:13:25 GMT",
"version": "v1"
},
{
"created": "Fri, 3 Feb 2006 10:50:27 GMT",
"version": "v2"
}
] |
2007-05-23
|
[
[
"Dolgov",
"A. D.",
""
]
] |
Cosmological implications of asymmetry between particles and antiparticles are reviewed. Three possible mechanisms of CP-violation in cosmology are described. General features of kinetics of generation of cosmological charge asymmetry are discussed in detail. In particular, the cyclic balance condition, which plays the same role in time non-invariant theory as detailed balance does in T-invariant case, is derived. Several scenarios of baryogenesis are described with an emphasis on CP-violation mechanisms. Production of cosmic antimatter and a possibility of its ``living'' in our neighborhood is discussed.
|
hep-ph/0103276
|
Alfred Tang
|
Alfred Tang and John W. Norbury
|
The Nystrom plus Correction Method for Solving Bound State Equations in
Momentum Space
|
Revtex, 21 pages, 4 tables, to be published in Physical Review E
|
Phys.Rev. E63 (2001) 066703
|
10.1103/PhysRevE.63.066703
| null |
hep-ph physics.comp-ph
| null |
A new method is presented for solving the momentum-space Schrodinger equation
with a linear potential. The Lande-subtracted momentum space integral equation
can be transformed into a matrix equation by the Nystrom method. The method
produces only approximate eigenvalues in the cases of singular potentials such
as the linear potential. The eigenvalues generated by the Nystrom method can be
improved by calculating the numerical errors and adding the appropriate
corrections. The end results are more accurate eigenvalues than those generated
by the basis function method. The method is also shown to work for a
relativistic equation such as the Thompson equation.
|
[
{
"created": "Mon, 26 Mar 2001 19:22:32 GMT",
"version": "v1"
}
] |
2009-11-07
|
[
[
"Tang",
"Alfred",
""
],
[
"Norbury",
"John W.",
""
]
] |
A new method is presented for solving the momentum-space Schrodinger equation with a linear potential. The Lande-subtracted momentum space integral equation can be transformed into a matrix equation by the Nystrom method. The method produces only approximate eigenvalues in the cases of singular potentials such as the linear potential. The eigenvalues generated by the Nystrom method can be improved by calculating the numerical errors and adding the appropriate corrections. The end results are more accurate eigenvalues than those generated by the basis function method. The method is also shown to work for a relativistic equation such as the Thompson equation.
|
1210.7863
|
Aleksander Kusina
|
S. Jadach, A. Kusina, M. Skrzypek, M. Slawinska
|
NLO parton shower for LHC physics - hard processes and beyond
|
Contribution to Loops and Legs in Quantum Field Theory 2012
|
PoS(LL2012)019
| null |
IFJPAN-IV-2012-10
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The new methodology of adding QCD NLO corrections in the initial state Monte
Carlo parton shower (hard process part) is presented using process of the heavy
boson production at the LHC as an example. Despite the simplified model of the
process, presented numerical results prove that the basic concept of the new
methodology works correctly in the numerical environment of the Monte Carlo
parton shower event generator. The presented method is an alternative to the
well established methods, MC@NLO and POWHEG. Refinements of the new method with
better computer CPU time efficiency are also discussed.
|
[
{
"created": "Mon, 29 Oct 2012 23:12:53 GMT",
"version": "v1"
}
] |
2012-10-31
|
[
[
"Jadach",
"S.",
""
],
[
"Kusina",
"A.",
""
],
[
"Skrzypek",
"M.",
""
],
[
"Slawinska",
"M.",
""
]
] |
The new methodology of adding QCD NLO corrections in the initial state Monte Carlo parton shower (hard process part) is presented using process of the heavy boson production at the LHC as an example. Despite the simplified model of the process, presented numerical results prove that the basic concept of the new methodology works correctly in the numerical environment of the Monte Carlo parton shower event generator. The presented method is an alternative to the well established methods, MC@NLO and POWHEG. Refinements of the new method with better computer CPU time efficiency are also discussed.
|
hep-ph/9511431
|
Tomohiro Hotta
|
T. Hotta, K.-I. Izawa and T. Yanagida
|
Quantum Restoration of the U(1)_Y Symmetry in Dynamically Broken
SUSY-GUT's
|
12 pages, LaTeX, 1 Postscript figure
|
Phys.Lett.B409:245-250,1997
|
10.1016/S0370-2693(97)00797-1
|
UT-733
|
hep-ph
| null |
We propose a supersymmetric hypercolor SU(3)_H gauge theory interacting
strongly at the grand unification scale, in which the hyperquark condensation
breaks SU(5)_GUT down to SU(3)_C x SU(2)_L without unbroken U(1)_Y at the
classical level. However, we show that the broken U(1)_Y symmetry is restored
by quantum mechanical effects and hence there remains the standard-model gauge
symmetry at the electroweak scale. The dynamics of the strong interactions also
produces naturally a pair of massless Higgs doublets. In addition to these
Higgs doublets, we have a pair of massless singlets which contributes to the
renormalization-group equations of gauge coupling constants and hence affects
the GUT unification. We discuss a simple solution to this problem.
|
[
{
"created": "Tue, 28 Nov 1995 09:42:54 GMT",
"version": "v1"
}
] |
2009-02-19
|
[
[
"Hotta",
"T.",
""
],
[
"Izawa",
"K. -I.",
""
],
[
"Yanagida",
"T.",
""
]
] |
We propose a supersymmetric hypercolor SU(3)_H gauge theory interacting strongly at the grand unification scale, in which the hyperquark condensation breaks SU(5)_GUT down to SU(3)_C x SU(2)_L without unbroken U(1)_Y at the classical level. However, we show that the broken U(1)_Y symmetry is restored by quantum mechanical effects and hence there remains the standard-model gauge symmetry at the electroweak scale. The dynamics of the strong interactions also produces naturally a pair of massless Higgs doublets. In addition to these Higgs doublets, we have a pair of massless singlets which contributes to the renormalization-group equations of gauge coupling constants and hence affects the GUT unification. We discuss a simple solution to this problem.
|
1708.05389
|
Yue Zhao
|
Aaron Pierce, Bibhushan Shakya, Yuhsin Tsai and Yue Zhao
|
Searching for Confining Hidden Valleys at the LHC(b)
|
6 pages, 3 figures
|
Phys. Rev. D 97, 095033 (2018)
|
10.1103/PhysRevD.97.095033
|
MCTP-17-13, PP-017-28
|
hep-ph hep-ex
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We explore strategies for probing Hidden Valley scenarios exhibiting
confinement. Such scenarios lead to a multiplicity of light hidden hadrons from
showering processes. Their decays are typically soft and displaced, making them
challenging to probe with traditional LHC searches. We show the low trigger
thresholds and excellent track and vertex reconstruction at LHCb provide an
ideal environment to search for such signals -- in both muonic and hadronic
channels. We also explore the potential of ATLAS/CMS and discuss modifications
to present searches that might make these experiments competitive with the LHCb
reach. Our proposed searches can probe $Z^{\prime}$ models with dominant decays
to dark sectors as well as exotic Higgs boson decays in Twin Higgs models.
|
[
{
"created": "Thu, 17 Aug 2017 18:00:01 GMT",
"version": "v1"
}
] |
2018-05-30
|
[
[
"Pierce",
"Aaron",
""
],
[
"Shakya",
"Bibhushan",
""
],
[
"Tsai",
"Yuhsin",
""
],
[
"Zhao",
"Yue",
""
]
] |
We explore strategies for probing Hidden Valley scenarios exhibiting confinement. Such scenarios lead to a multiplicity of light hidden hadrons from showering processes. Their decays are typically soft and displaced, making them challenging to probe with traditional LHC searches. We show the low trigger thresholds and excellent track and vertex reconstruction at LHCb provide an ideal environment to search for such signals -- in both muonic and hadronic channels. We also explore the potential of ATLAS/CMS and discuss modifications to present searches that might make these experiments competitive with the LHCb reach. Our proposed searches can probe $Z^{\prime}$ models with dominant decays to dark sectors as well as exotic Higgs boson decays in Twin Higgs models.
|
1005.0066
|
Xiang Liu
|
Dian-Yong Chen, Yu-Bing Dong and Xiang Liu
|
Long-distant contribution and $\chi_{c1}$ radiative decays to light
vector meson
|
7 pages, 2 figures. Accepted for publication in Eur. Phys. J. C
|
Eur.Phys.J.C70:177-182,2010
|
10.1140/epjc/s10052-010-1449-5
| null |
hep-ph hep-ex nucl-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The discrepancy between the PQCD calculation and the CLEO data for
$\chi_{c1}\to \gamma V$ ($V=\rho^0,\,\omega,\,\phi$) stimulates our interest in
exploring extra mechanism of $\chi_{c1}$ decay. In this work, we apply an
important non-perturbative QCD effect, i.e., hadronic loop mechanism, to study
$\chi_{c1}\to \gamma V$ radiative decay. Our numerical result shows that the
theoretical results including the hadronic loop contribution and the PQCD
calculation of $\chi_{c1}\to \gamma V$ are consistent with the corresponding
CLEO data of $\chi_{c1}\to \gamma V$. We expect further experimental
measurement of $\chi_{c1}\to \gamma V$ at BES-III, which will be helpful to
test the hadronic loop effect on $\chi_{c1}$ decay.
|
[
{
"created": "Sat, 1 May 2010 12:57:39 GMT",
"version": "v1"
},
{
"created": "Wed, 5 May 2010 08:20:06 GMT",
"version": "v2"
},
{
"created": "Wed, 16 Jun 2010 00:21:46 GMT",
"version": "v3"
},
{
"created": "Wed, 8 Sep 2010 04:59:04 GMT",
"version": "v4"
}
] |
2010-11-23
|
[
[
"Chen",
"Dian-Yong",
""
],
[
"Dong",
"Yu-Bing",
""
],
[
"Liu",
"Xiang",
""
]
] |
The discrepancy between the PQCD calculation and the CLEO data for $\chi_{c1}\to \gamma V$ ($V=\rho^0,\,\omega,\,\phi$) stimulates our interest in exploring extra mechanism of $\chi_{c1}$ decay. In this work, we apply an important non-perturbative QCD effect, i.e., hadronic loop mechanism, to study $\chi_{c1}\to \gamma V$ radiative decay. Our numerical result shows that the theoretical results including the hadronic loop contribution and the PQCD calculation of $\chi_{c1}\to \gamma V$ are consistent with the corresponding CLEO data of $\chi_{c1}\to \gamma V$. We expect further experimental measurement of $\chi_{c1}\to \gamma V$ at BES-III, which will be helpful to test the hadronic loop effect on $\chi_{c1}$ decay.
|
1410.2417
|
Alfredo Vega Dr.
|
Alfredo Vega and Jorge Flores
|
Heavy quarkonium properties from Cornell potential using variational
method and supersymmetric quantum mechanic
| null | null | null | null |
hep-ph nucl-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Using the variational method and supersymmetric quantum mechanic we calculate
in a approximate way eigenvalues, eigenfunctions and wave functions at origin
of Cornell potential. We compare results with numerical solutions for heavy
quarkonia $c\bar{c}$, $b\bar{b}$ y $b\bar{c}$.
|
[
{
"created": "Thu, 9 Oct 2014 10:43:41 GMT",
"version": "v1"
}
] |
2014-10-10
|
[
[
"Vega",
"Alfredo",
""
],
[
"Flores",
"Jorge",
""
]
] |
Using the variational method and supersymmetric quantum mechanic we calculate in a approximate way eigenvalues, eigenfunctions and wave functions at origin of Cornell potential. We compare results with numerical solutions for heavy quarkonia $c\bar{c}$, $b\bar{b}$ y $b\bar{c}$.
|
0812.2341
|
W. James Stirling
|
W. James Stirling
|
Progress in Parton Distribution Functions
|
9 pages, 5 figures, presented at ISMD08, DESY, Hamburg, September
2008
| null | null |
CAVENDISH-HEP-08-15
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Parton distribution functions (pdfs) are an important ingredient for LHC
phenomenology. Recent progress in determining pdfs from global analyses is
reviewed, and some of the most important outstanding issues are highlighted.
Particular attention is paid to the precision with which predictions for LHC
`standard-candle' cross sections can be made, and also to new information that
LHC can provide on pdfs.
|
[
{
"created": "Fri, 12 Dec 2008 10:32:00 GMT",
"version": "v1"
}
] |
2008-12-15
|
[
[
"Stirling",
"W. James",
""
]
] |
Parton distribution functions (pdfs) are an important ingredient for LHC phenomenology. Recent progress in determining pdfs from global analyses is reviewed, and some of the most important outstanding issues are highlighted. Particular attention is paid to the precision with which predictions for LHC `standard-candle' cross sections can be made, and also to new information that LHC can provide on pdfs.
|
hep-ph/9707384
|
Davison E. Soper
|
Davison E. Soper
|
Diffraction in DIS and Elsewhere
|
Talk at DIS97 Conference, Chicago, April 1997. Eleven pages including
nine figures
| null |
10.1063/1.53586
| null |
hep-ph
| null |
I review some of the results presented in the working group on diffraction at
DIS97, with a particular emphasis on the theory of diffractive hard scattering.
|
[
{
"created": "Thu, 17 Jul 1997 22:32:54 GMT",
"version": "v1"
}
] |
2009-10-30
|
[
[
"Soper",
"Davison E.",
""
]
] |
I review some of the results presented in the working group on diffraction at DIS97, with a particular emphasis on the theory of diffractive hard scattering.
|
2310.19853
|
Fabian Rennecke
|
Jens Braun, Yong-rui Chen, Wei-jie Fu, Fei Gao, Chuang Huang,
Friederike Ihssen, Jan M. Pawlowski, Fabian Rennecke, Franz R. Sattler,
Yang-yang Tan, Rui Wen, Shi Yin
|
Soft modes in hot QCD matter
|
7+8 pages, 5+4 figures
| null | null | null |
hep-ph hep-lat hep-th nucl-th
|
http://creativecommons.org/licenses/by/4.0/
|
The chiral crossover of QCD at finite temperature and vanishing baryon
density turns into a second order phase transition if lighter than physical
quark masses are considered. If this transition occurs sufficiently close to
the physical point, its universal critical behaviour would largely control the
physics of the QCD phase transition. We quantify the size of this region in QCD
using functional approaches, both Dyson-Schwinger equations and the functional
renormalisation group. The latter allows us to study both critical and
non-critical effects on an equal footing, facilitating a precise determination
of the scaling regime. We find that the physical point is far away from the
critical region. Importantly, we show that the physics of the chiral crossover
is dominated by soft modes even far beyond the critical region. While scaling
functions determine all thermodynamic properties of the system in the critical
region, the order parameter potential is the relevant quantity away from it. We
compute this potential in QCD using the functional renormalisation group and
Dyson-Schwinger equations and provide a simple parametrisation for
phenomenological applications.
|
[
{
"created": "Mon, 30 Oct 2023 16:00:30 GMT",
"version": "v1"
}
] |
2023-11-01
|
[
[
"Braun",
"Jens",
""
],
[
"Chen",
"Yong-rui",
""
],
[
"Fu",
"Wei-jie",
""
],
[
"Gao",
"Fei",
""
],
[
"Huang",
"Chuang",
""
],
[
"Ihssen",
"Friederike",
""
],
[
"Pawlowski",
"Jan M.",
""
],
[
"Rennecke",
"Fabian",
""
],
[
"Sattler",
"Franz R.",
""
],
[
"Tan",
"Yang-yang",
""
],
[
"Wen",
"Rui",
""
],
[
"Yin",
"Shi",
""
]
] |
The chiral crossover of QCD at finite temperature and vanishing baryon density turns into a second order phase transition if lighter than physical quark masses are considered. If this transition occurs sufficiently close to the physical point, its universal critical behaviour would largely control the physics of the QCD phase transition. We quantify the size of this region in QCD using functional approaches, both Dyson-Schwinger equations and the functional renormalisation group. The latter allows us to study both critical and non-critical effects on an equal footing, facilitating a precise determination of the scaling regime. We find that the physical point is far away from the critical region. Importantly, we show that the physics of the chiral crossover is dominated by soft modes even far beyond the critical region. While scaling functions determine all thermodynamic properties of the system in the critical region, the order parameter potential is the relevant quantity away from it. We compute this potential in QCD using the functional renormalisation group and Dyson-Schwinger equations and provide a simple parametrisation for phenomenological applications.
|
hep-ph/0612023
|
Vedat N. Senoguz
|
Mansoor ur Rehman, V. N. Senoguz, Qaisar Shafi
|
Supersymmetric And Smooth Hybrid Inflation In The Light Of WMAP3
|
21 pages, 12 figures, revtex4. v2: minor revisions, additional
references, to appear in PRD
|
Phys.Rev.D75:043522,2007
|
10.1103/PhysRevD.75.043522
|
BA-06-18
|
hep-ph
| null |
In their minimal form both supersymmetric and smooth hybrid inflation yield a
scalar spectral index n_s close to 0.98, to be contrasted with the result
n_s=0.951+0.015-0.019 from WMAP3. To realize better agreement, following
hep-ph/0604198, we extend the parameter space of these models by employing a
non-minimal Kaehler potential. We also discuss non-thermal leptogenesis by
inflaton decay and obtain new bounds in these models on the reheat temperature
to explain the observed baryon asymmetry.
|
[
{
"created": "Mon, 4 Dec 2006 17:33:18 GMT",
"version": "v1"
},
{
"created": "Mon, 5 Feb 2007 18:03:57 GMT",
"version": "v2"
}
] |
2008-11-26
|
[
[
"Rehman",
"Mansoor ur",
""
],
[
"Senoguz",
"V. N.",
""
],
[
"Shafi",
"Qaisar",
""
]
] |
In their minimal form both supersymmetric and smooth hybrid inflation yield a scalar spectral index n_s close to 0.98, to be contrasted with the result n_s=0.951+0.015-0.019 from WMAP3. To realize better agreement, following hep-ph/0604198, we extend the parameter space of these models by employing a non-minimal Kaehler potential. We also discuss non-thermal leptogenesis by inflaton decay and obtain new bounds in these models on the reheat temperature to explain the observed baryon asymmetry.
|
hep-ph/9712237
|
Ugo Aglietti UA
|
U. Aglietti (Rome I University), G. Corbo` (Rome I University), L.
Trentadue (Parma University)
|
Leading Logarithms in Field Theory
|
Latex file, 20 pages, no figures, corrected some typos
|
Int.J.Mod.Phys. A14 (1999) 1769-1788
|
10.1142/S0217751X99000907
|
Rome I preprint ROME1 1187/97 and Parma preprint UPRF-97-020
|
hep-ph
| null |
We consider the Sudakov form factor in effective theories and we show that
one can derive correctly the double logarithms of the original, high-energy,
theory. We show that in effective theories it is possible to separate
explicitely soft and hard dynamics being these two regimes related to velocity
conserving and to velocity changing operators respectively. A new effective
theory is sketched which extracts the leading collinear singularities of the
full theory amplitudes. Finally, we show how all leading logarithmic effects in
field theory can be obtained by means of simple effective theories, where they
correspond to a renormalization effect.
|
[
{
"created": "Tue, 2 Dec 1997 19:46:39 GMT",
"version": "v1"
},
{
"created": "Fri, 5 Dec 1997 14:22:22 GMT",
"version": "v2"
}
] |
2009-10-30
|
[
[
"Aglietti",
"U.",
"",
"Rome I University"
],
[
"Corbo`",
"G.",
"",
"Rome I University"
],
[
"Trentadue",
"L.",
"",
"Parma University"
]
] |
We consider the Sudakov form factor in effective theories and we show that one can derive correctly the double logarithms of the original, high-energy, theory. We show that in effective theories it is possible to separate explicitely soft and hard dynamics being these two regimes related to velocity conserving and to velocity changing operators respectively. A new effective theory is sketched which extracts the leading collinear singularities of the full theory amplitudes. Finally, we show how all leading logarithmic effects in field theory can be obtained by means of simple effective theories, where they correspond to a renormalization effect.
|
2203.11736
|
Sumit Ghosh
|
James B. Dent, Bhaskar Dutta, Sumit Ghosh, Jason Kumar, Jack Runburg
|
Sensitivity to Dark Sector Scales from Gravitational Wave Signatures
|
Matches the journal version. Minor updates in text
|
JHEP 08 (2022) 300
|
10.1007/JHEP08(2022)300
|
MI-HET-774, KIAS-P22016
|
hep-ph astro-ph.CO
|
http://creativecommons.org/licenses/by/4.0/
|
We consider gravitational wave signals produced by a first-order phase
transition in a theory with a generic renormalizable thermal effective
potential of power law form. We find the frequency and amplitude of the
gravitational wave signal can be related in a straightforward manner to the
parameters of the thermal effective potential. This leads to a general
conclusion; if the mass of the dark Higgs is less than 1% of the dark Higgs
vacuum expectation value, then the gravitational wave signal will be
unobservable at all upcoming and planned gravitational wave observatories.
|
[
{
"created": "Tue, 22 Mar 2022 13:44:25 GMT",
"version": "v1"
},
{
"created": "Wed, 7 Sep 2022 06:21:11 GMT",
"version": "v2"
}
] |
2022-09-08
|
[
[
"Dent",
"James B.",
""
],
[
"Dutta",
"Bhaskar",
""
],
[
"Ghosh",
"Sumit",
""
],
[
"Kumar",
"Jason",
""
],
[
"Runburg",
"Jack",
""
]
] |
We consider gravitational wave signals produced by a first-order phase transition in a theory with a generic renormalizable thermal effective potential of power law form. We find the frequency and amplitude of the gravitational wave signal can be related in a straightforward manner to the parameters of the thermal effective potential. This leads to a general conclusion; if the mass of the dark Higgs is less than 1% of the dark Higgs vacuum expectation value, then the gravitational wave signal will be unobservable at all upcoming and planned gravitational wave observatories.
|
2110.07199
|
Toru Nishimura
|
Toru Nishimura, Masakiyo Kitazawa and Teiji Kunihiro
|
Dilepton production rate near the critical temperature of color
superconductivity
|
6 pages, 9 figures. Proceedings for the International Conference on
Critical Point and Onset of Deconfinement - CPOD2021, 15 - 19 March 2021,
Online - zoom
| null | null |
J-PARC-TH-0251
|
hep-ph
|
http://creativecommons.org/licenses/by/4.0/
|
We investigate modification of the dilepton production rate by the diquark
fluctuations that form well-developed collective modes near the critical
temperature of color superconductivity. Through the analysis of the photon
self-energy called the Aslamasov-Larkin, Maki-Thompson and density of states
terms in the theory of metalic superconductivity, it is shown that the
collective mode in the diquark channel affects the photon self-energy
significantly and thereby gives rise to an anomalous enhacement of the dilepton
production rate in the low invariant-mass region.
|
[
{
"created": "Thu, 14 Oct 2021 07:47:32 GMT",
"version": "v1"
}
] |
2021-10-15
|
[
[
"Nishimura",
"Toru",
""
],
[
"Kitazawa",
"Masakiyo",
""
],
[
"Kunihiro",
"Teiji",
""
]
] |
We investigate modification of the dilepton production rate by the diquark fluctuations that form well-developed collective modes near the critical temperature of color superconductivity. Through the analysis of the photon self-energy called the Aslamasov-Larkin, Maki-Thompson and density of states terms in the theory of metalic superconductivity, it is shown that the collective mode in the diquark channel affects the photon self-energy significantly and thereby gives rise to an anomalous enhacement of the dilepton production rate in the low invariant-mass region.
|
2209.10902
|
Volodymyr Takhistov
|
Muping Chen, Graciela B. Gelmini, Volodymyr Takhistov
|
Halo-Independent Dark Matter Electron Scattering Analysis with In-Medium
Effects
|
9 pages, 5 figures
| null |
10.1016/j.physletb.2023.137922
|
KEK-QUP-2022-0002, KEK-TH-2450, KEK-Cosmo-0296, IPMU22-0048
|
hep-ph astro-ph.CO hep-ex
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Dark matter (DM)-electron scattering is a prime target of a number of direct
DM detection experiments and constitutes a promising avenue for exploring
interactions of DM in the sub-GeV mass-range, challenging to probe with nuclear
recoils. We extend the recently proposed halo-independent analysis method for
DM-electron scattering, which allows to infer the local DM halo properties
without any additional assumptions about them, to include in-medium effects
through dielectric functions of the target material. We show that in-medium
effects could significantly affect halo-independent analysis response functions
for germanium and silicon and thus are essential for proper inference of local
DM halo characteristics from direct DM detection data.
|
[
{
"created": "Thu, 22 Sep 2022 10:19:54 GMT",
"version": "v1"
}
] |
2023-05-17
|
[
[
"Chen",
"Muping",
""
],
[
"Gelmini",
"Graciela B.",
""
],
[
"Takhistov",
"Volodymyr",
""
]
] |
Dark matter (DM)-electron scattering is a prime target of a number of direct DM detection experiments and constitutes a promising avenue for exploring interactions of DM in the sub-GeV mass-range, challenging to probe with nuclear recoils. We extend the recently proposed halo-independent analysis method for DM-electron scattering, which allows to infer the local DM halo properties without any additional assumptions about them, to include in-medium effects through dielectric functions of the target material. We show that in-medium effects could significantly affect halo-independent analysis response functions for germanium and silicon and thus are essential for proper inference of local DM halo characteristics from direct DM detection data.
|
1307.6764
|
Federico Marquez
|
M. Loewe, F. Marquez and C. Villavicencio
|
The nNJL model with a fractional Lorentzian regulator in the real time
formalism
|
New figures, new references and new comments were added to the
manuscript. To appear in Phys. Rev. D
| null |
10.1103/PhysRevD.88.056004
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
In this article we study the finite temperature and chemical potential
effects in a nonlocal Nambu-Jona-Lasinio (nNJL) model in the real time
formalism. We make the usual Wick rotation to get from imaginary to real time
formalism. In doing so, we need to define our regulator in the complex plane
q^2. This deffinition will be crucial in our later analysis. We study the poles
in the propagator of this model and conclude that only some of them are of
interst to us. Once we have a well defined model in real time formalism, we
look at the chiral condensate to find the temperature at which chiral symmetry
restoration will occur. We find a second order phase transition that turns to a
first order one for high enough values of the chemical potential.
|
[
{
"created": "Thu, 25 Jul 2013 14:56:29 GMT",
"version": "v1"
},
{
"created": "Mon, 26 Aug 2013 19:57:17 GMT",
"version": "v2"
},
{
"created": "Fri, 30 Aug 2013 16:03:07 GMT",
"version": "v3"
}
] |
2013-09-11
|
[
[
"Loewe",
"M.",
""
],
[
"Marquez",
"F.",
""
],
[
"Villavicencio",
"C.",
""
]
] |
In this article we study the finite temperature and chemical potential effects in a nonlocal Nambu-Jona-Lasinio (nNJL) model in the real time formalism. We make the usual Wick rotation to get from imaginary to real time formalism. In doing so, we need to define our regulator in the complex plane q^2. This deffinition will be crucial in our later analysis. We study the poles in the propagator of this model and conclude that only some of them are of interst to us. Once we have a well defined model in real time formalism, we look at the chiral condensate to find the temperature at which chiral symmetry restoration will occur. We find a second order phase transition that turns to a first order one for high enough values of the chemical potential.
|
1809.06175
|
Adolfo Guevara
|
Adolfo Guevara, Pablo Roig, JJ Sanz Cillero
|
Pseudoscalar pole contribution to the hadronic light-by-light piece of
$a_\mu$
|
7 pages, 3 figures, Proceedings for the workshop QCD@Work
| null |
10.1051/epjconf/201819200027
| null |
hep-ph
|
http://creativecommons.org/licenses/by/4.0/
|
We have studied the $P\to\gamma^\star\gamma^\star$ form factor in Resonance
Chiral Theory, with $P = \pi^0,\eta,\eta'$, to compute the contribution of the
pseudoscalar pole to the hadronic light-by-light piece of the anomalous
magnetic moment of the muon. In this work we allow the leading $U(3)$ chiral
symmetry breaking terms, obtaining the most general expression for the form
factor of order $\mathcal{O}(m_P^2)$. The parameters of the Effective Field
Theory are obtained by means of short distance constraints on the form factor
and matching with the expected behavior from QCD. Those parameters that cannot
be fixed in this way are fitted to experimental determinations of the form
factor within the spacelike momentum region of the virtual photon. Chiral
symmetry relations among the transition form factors for $\pi^0,\eta$ and
$\eta'$ allow for a simultaneous fit to experimental data for the three mesons.
This shows an inconsistency between the BaBar $\pi^0$ data and the rest of the
experimental inputs. Thus, we find a total pseudoscalar pole contribution of
$a_\mu^{P,HLbL}=(8.47\pm 0.16)\cdot 10^{-10}$ for our best fit (neglecting the
BaBar $\pi^0$ data). Also, a preliminary rough estimate of the impact of NLO in
$1/N_C$ corrections and higher vector multiplets (asym) enlarges the
uncertainty up to $a_\mu^{P,HLbL}=(8.47\pm 0.16_{\rm stat}\pm
0.09_{N_C}{}^{+0.5}_{-0.0_{\rm asym}})$
|
[
{
"created": "Mon, 17 Sep 2018 13:04:30 GMT",
"version": "v1"
}
] |
2018-12-05
|
[
[
"Guevara",
"Adolfo",
""
],
[
"Roig",
"Pablo",
""
],
[
"Cillero",
"JJ Sanz",
""
]
] |
We have studied the $P\to\gamma^\star\gamma^\star$ form factor in Resonance Chiral Theory, with $P = \pi^0,\eta,\eta'$, to compute the contribution of the pseudoscalar pole to the hadronic light-by-light piece of the anomalous magnetic moment of the muon. In this work we allow the leading $U(3)$ chiral symmetry breaking terms, obtaining the most general expression for the form factor of order $\mathcal{O}(m_P^2)$. The parameters of the Effective Field Theory are obtained by means of short distance constraints on the form factor and matching with the expected behavior from QCD. Those parameters that cannot be fixed in this way are fitted to experimental determinations of the form factor within the spacelike momentum region of the virtual photon. Chiral symmetry relations among the transition form factors for $\pi^0,\eta$ and $\eta'$ allow for a simultaneous fit to experimental data for the three mesons. This shows an inconsistency between the BaBar $\pi^0$ data and the rest of the experimental inputs. Thus, we find a total pseudoscalar pole contribution of $a_\mu^{P,HLbL}=(8.47\pm 0.16)\cdot 10^{-10}$ for our best fit (neglecting the BaBar $\pi^0$ data). Also, a preliminary rough estimate of the impact of NLO in $1/N_C$ corrections and higher vector multiplets (asym) enlarges the uncertainty up to $a_\mu^{P,HLbL}=(8.47\pm 0.16_{\rm stat}\pm 0.09_{N_C}{}^{+0.5}_{-0.0_{\rm asym}})$
|
1603.09691
|
George De Conto
|
G. De Conto and V. Pleitez
|
Electron and muon anomalous magnetic dipole moment in a 3-3-1 model
|
34 pages, 19 figures
| null |
10.1007/JHEP05(2017)104
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We calculate, in the context of a 3-3-1 model with heavy charged leptons,
constraints on some parameters of the extra particles in the model by imposing
that their contributions to both the electron and muon $(g-2)$ factors are in
agreement with experimental data up to 1$\sigma$-3$\sigma$. In order to obtain
realistic results we use some of the possible solutions of the left- and right-
unitary matrices that diagonalize the lepton mass matrices, giving the observed
lepton masses and at the same time allowing to accommodate the
Pontecorvo-Maki-Nakagawa-Sakata (PMNS) mixing matrix. We show that, at least up
to 1-loop order, in the particular range of the space parameter that we have
explored, it is not possible to fit the observed electron and muon $(g-2)$
factors at the same time unless one of the extra leptons has a mass of the
order of 20-40 GeVs and the energy scale of the 331 symmetry to be of around
60-80 TeVs.
|
[
{
"created": "Thu, 31 Mar 2016 17:21:41 GMT",
"version": "v1"
},
{
"created": "Mon, 22 May 2017 15:06:35 GMT",
"version": "v2"
}
] |
2017-05-23
|
[
[
"De Conto",
"G.",
""
],
[
"Pleitez",
"V.",
""
]
] |
We calculate, in the context of a 3-3-1 model with heavy charged leptons, constraints on some parameters of the extra particles in the model by imposing that their contributions to both the electron and muon $(g-2)$ factors are in agreement with experimental data up to 1$\sigma$-3$\sigma$. In order to obtain realistic results we use some of the possible solutions of the left- and right- unitary matrices that diagonalize the lepton mass matrices, giving the observed lepton masses and at the same time allowing to accommodate the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) mixing matrix. We show that, at least up to 1-loop order, in the particular range of the space parameter that we have explored, it is not possible to fit the observed electron and muon $(g-2)$ factors at the same time unless one of the extra leptons has a mass of the order of 20-40 GeVs and the energy scale of the 331 symmetry to be of around 60-80 TeVs.
|
2309.04055
|
Rafael Cardoso MSc
|
William R. Tavares, Sidney S. Avancini, Ricardo L. S. Farias and
Rafael P. Cardoso
|
Artificial first-order phase transition in a magnetized
Nambu--Jona-Lasinio model with a quark anomalous magnetic moment
|
Typos corrected, comments added and new structure. Matches published
version
|
Phys. Rev. D 109 (2024) 016011
|
10.1103/PhysRevD.109.016011
| null |
hep-ph hep-lat hep-th nucl-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Recently, first-order phase transitions have been predicted as an effect of
the inclusion of quark anomalous magnetic moment (AMM) in the hot and
magnetized Nambu--Jona-Lasinio model (NJL). These transitions appear in the
chiral condensate for different combinations of AMM and magnetic fields and
could lead to inverse magnetic catalysis. However, in this work, we show that
the predicted first-order phase transitions are related to
regularization-dependent issues. To show this, we explore, in the context of
the vacuum magnetic regularization (VMR) scheme, two different scenarios: when
mass-dependent (MD) and mass-independent (MI) terms are present in the
subtraction of the divergences. In the MD case, as we increase the AMM value,
it is observed the appearance of a nonmassive minimum in the thermodynamical
potential, which induces a first-order phase transition from the massive
minimum. We argue that the MD terms must be avoided in order to satisfy the
predictions of Lattice QCD, and we propose a MI solution that is valid in the
limit which the magnetic fields are smaller than the squared of vacuum
effective quark mass.
|
[
{
"created": "Fri, 8 Sep 2023 01:03:23 GMT",
"version": "v1"
},
{
"created": "Tue, 9 Jan 2024 18:35:19 GMT",
"version": "v2"
}
] |
2024-01-10
|
[
[
"Tavares",
"William R.",
""
],
[
"Avancini",
"Sidney S.",
""
],
[
"Farias",
"Ricardo L. S.",
""
],
[
"Cardoso",
"Rafael P.",
""
]
] |
Recently, first-order phase transitions have been predicted as an effect of the inclusion of quark anomalous magnetic moment (AMM) in the hot and magnetized Nambu--Jona-Lasinio model (NJL). These transitions appear in the chiral condensate for different combinations of AMM and magnetic fields and could lead to inverse magnetic catalysis. However, in this work, we show that the predicted first-order phase transitions are related to regularization-dependent issues. To show this, we explore, in the context of the vacuum magnetic regularization (VMR) scheme, two different scenarios: when mass-dependent (MD) and mass-independent (MI) terms are present in the subtraction of the divergences. In the MD case, as we increase the AMM value, it is observed the appearance of a nonmassive minimum in the thermodynamical potential, which induces a first-order phase transition from the massive minimum. We argue that the MD terms must be avoided in order to satisfy the predictions of Lattice QCD, and we propose a MI solution that is valid in the limit which the magnetic fields are smaller than the squared of vacuum effective quark mass.
|
1404.1033
|
Andreas Metz
|
K. Kanazawa, Y. Koike, A. Metz, D. Pitonyak
|
Towards an explanation of transverse single-spin asymmetries in
proton-proton collisions: the role of fragmentation in collinear
factorization
|
minor changes, matches journal version
| null |
10.1103/PhysRevD.89.111501
|
RBRC-1065
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We study the transverse single-spin asymmetry for single-hadron production in
proton-proton collisions within the framework of collinear twist-3
factorization in Quantum Chromodynamics. By taking into account the
contribution due to parton fragmentation we obtain a very good description of
all high transverse-momentum data for neutral and charged pion production from
the Relativistic Heavy Ion Collider. Our study may provide the crucial step
towards a final solution to the longstanding problem of what causes transverse
single-spin asymmetries in hadronic collisions within Quantum Chromodynamics.
We show for the first time that it is possible to simultaneously describe
spin/azimuthal asymmetries in proton-proton collisions, semi-inclusive
deep-inelastic scattering, and electron-positron annihilation by using
collinear twist-3 factorization in the first process along with transverse
momentum dependent functions extracted from the latter two reactions.
|
[
{
"created": "Thu, 3 Apr 2014 18:35:46 GMT",
"version": "v1"
},
{
"created": "Fri, 30 May 2014 12:26:38 GMT",
"version": "v2"
}
] |
2015-06-19
|
[
[
"Kanazawa",
"K.",
""
],
[
"Koike",
"Y.",
""
],
[
"Metz",
"A.",
""
],
[
"Pitonyak",
"D.",
""
]
] |
We study the transverse single-spin asymmetry for single-hadron production in proton-proton collisions within the framework of collinear twist-3 factorization in Quantum Chromodynamics. By taking into account the contribution due to parton fragmentation we obtain a very good description of all high transverse-momentum data for neutral and charged pion production from the Relativistic Heavy Ion Collider. Our study may provide the crucial step towards a final solution to the longstanding problem of what causes transverse single-spin asymmetries in hadronic collisions within Quantum Chromodynamics. We show for the first time that it is possible to simultaneously describe spin/azimuthal asymmetries in proton-proton collisions, semi-inclusive deep-inelastic scattering, and electron-positron annihilation by using collinear twist-3 factorization in the first process along with transverse momentum dependent functions extracted from the latter two reactions.
|
2006.11938
|
Motoo Suzuki
|
Keisuke Harigaya, Yuichiro Nakai, Motoo Suzuki
|
Inelastic Dark Matter Electron Scattering and the XENON1T Excess
|
7 pages, 5 figures, version to be published in Physics Letters B
| null |
10.1016/j.physletb.2020.135729
| null |
hep-ph astro-ph.CO hep-ex
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Detection of electron recoils by dark matter (DM) may reveal the structure of
the dark sector. We consider a scenario where a heavier DM particle
inelastically scatters off an electron and is converted into a lighter DM
particle. A small mass difference between the two DM particles is transferred
into electron recoil energy. We investigate the DM-electron interaction
mediated by a massive dark photon and evaluate the inelastic DM scattering
rate, taking account of the atomic structure. It is found that the scattering
rate is significantly enhanced because of the small mass splitting, which
allows for a small momentum transfer matched with the size of the electron wave
function. We show that there exists a viable parameter space which explains the
excess of electron recoil events around 2-3 keV recently reported by the
XENON1T experiment.
|
[
{
"created": "Sun, 21 Jun 2020 23:35:22 GMT",
"version": "v1"
},
{
"created": "Mon, 29 Jun 2020 13:19:04 GMT",
"version": "v2"
},
{
"created": "Fri, 28 Aug 2020 04:42:35 GMT",
"version": "v3"
}
] |
2020-09-02
|
[
[
"Harigaya",
"Keisuke",
""
],
[
"Nakai",
"Yuichiro",
""
],
[
"Suzuki",
"Motoo",
""
]
] |
Detection of electron recoils by dark matter (DM) may reveal the structure of the dark sector. We consider a scenario where a heavier DM particle inelastically scatters off an electron and is converted into a lighter DM particle. A small mass difference between the two DM particles is transferred into electron recoil energy. We investigate the DM-electron interaction mediated by a massive dark photon and evaluate the inelastic DM scattering rate, taking account of the atomic structure. It is found that the scattering rate is significantly enhanced because of the small mass splitting, which allows for a small momentum transfer matched with the size of the electron wave function. We show that there exists a viable parameter space which explains the excess of electron recoil events around 2-3 keV recently reported by the XENON1T experiment.
|
2103.04576
|
Ushak Rahaman
|
Ushak Rahaman
|
Looking for Lorentz invariance violation (LIV) in the latest long
baseline accelerator neutrino oscillation data
|
25 pages, 12 figures, Accepted in EPJC
| null |
10.1140/epjc/s10052-021-09598-4
| null |
hep-ph hep-ex hep-th
|
http://creativecommons.org/licenses/by/4.0/
|
In this paper, we have analysed the latest data from NO$\nu$A and T2K with
the Lorentz invariance violation along with the standard oscillation
hypothesis. We have found that the NO$\nu$A data cannot distinguish between the
two hypotheses at $1\, \sigma$ confidence level. T2K data and the combined data
analysis excluded standard oscillation at $1\, \sigma$. All three cases do not
have any hierarchy sensitivity when analysed with LIV. There is a mild tension
between the two experiments, when analysed with LIV, as $\theta_{23}$ at \nova
best-fit is at higher octant but the same for T2K is at lower octant. NO$\nu$A
has a new degeneracy over $\sin^2 \theta_{23}$ value, when analysed with LIV.
|
[
{
"created": "Mon, 8 Mar 2021 07:09:30 GMT",
"version": "v1"
},
{
"created": "Sat, 28 Aug 2021 09:58:19 GMT",
"version": "v2"
}
] |
2023-02-22
|
[
[
"Rahaman",
"Ushak",
""
]
] |
In this paper, we have analysed the latest data from NO$\nu$A and T2K with the Lorentz invariance violation along with the standard oscillation hypothesis. We have found that the NO$\nu$A data cannot distinguish between the two hypotheses at $1\, \sigma$ confidence level. T2K data and the combined data analysis excluded standard oscillation at $1\, \sigma$. All three cases do not have any hierarchy sensitivity when analysed with LIV. There is a mild tension between the two experiments, when analysed with LIV, as $\theta_{23}$ at \nova best-fit is at higher octant but the same for T2K is at lower octant. NO$\nu$A has a new degeneracy over $\sin^2 \theta_{23}$ value, when analysed with LIV.
|
1106.4538
|
Amir Fariborz
|
Amir H. Fariborz, Renata Jora, Joseph Schechter, M. Naeem Shahid
|
Chiral Nonet Mixing in pi pi Scattering
| null | null |
10.1103/PhysRevD.84.113004
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Pion pion scattering is studied in a generalized linear sigma model which
contains two scalar nonets (one of quark-antiquark type and the other of
diquark-antidiquark type) and two corresponding pseudoscalar nonets. An
interesting feature concerns the mixing of the four isosinglet scalar mesons
which yield poles in the scattering amplitude. Some realism is introduced by
enforcing exact unitarity via the K-matrix method.
It is shown that a reasonable agreement with experimental data is obtained up
to about 1 GeV. The poles in the unitarized scattering amplitude are studied in
some detail. The lowest pole clearly represents the sigma meson (or f0(600))
with a mass and decay width around 500 MeV. The second pole invites comparison
with the f0(980) which has a mass around 1 GeV and decay width around 100 MeV.
The third and fourth poles, resemble some of the isosinglet state in the
complicated 1-2 GeV region. Some comparison is made to the situation in the
usual SU(3) linear sigma model with a single scalar nonet.
|
[
{
"created": "Wed, 22 Jun 2011 19:33:24 GMT",
"version": "v1"
}
] |
2015-05-28
|
[
[
"Fariborz",
"Amir H.",
""
],
[
"Jora",
"Renata",
""
],
[
"Schechter",
"Joseph",
""
],
[
"Shahid",
"M. Naeem",
""
]
] |
Pion pion scattering is studied in a generalized linear sigma model which contains two scalar nonets (one of quark-antiquark type and the other of diquark-antidiquark type) and two corresponding pseudoscalar nonets. An interesting feature concerns the mixing of the four isosinglet scalar mesons which yield poles in the scattering amplitude. Some realism is introduced by enforcing exact unitarity via the K-matrix method. It is shown that a reasonable agreement with experimental data is obtained up to about 1 GeV. The poles in the unitarized scattering amplitude are studied in some detail. The lowest pole clearly represents the sigma meson (or f0(600)) with a mass and decay width around 500 MeV. The second pole invites comparison with the f0(980) which has a mass around 1 GeV and decay width around 100 MeV. The third and fourth poles, resemble some of the isosinglet state in the complicated 1-2 GeV region. Some comparison is made to the situation in the usual SU(3) linear sigma model with a single scalar nonet.
|
1607.00701
|
Zhi-Gang Wang
|
Zhi-Gang Wang
|
Reanalysis of the $X(4140)$ as axialvector tetraquark state with QCD sum
rules
|
20 pages, 15 figures
|
Eur. Phys. J. C76 (2016) 657
|
10.1140/epjc/s10052-016-4515-9
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
In this article, we take the $X(4140)$ as the diquark-antidiquark type
$cs\bar{c}\bar{s}$ tetraquark state with $J^{PC}=1^{++}$, and study the mass
and pole residue with the QCD sum rules in details by constructing two types
interpolating currents. The numerical results
$M_{X_{L,+}}=3.95\pm0.09\,\rm{GeV}$ and $M_{X_{H,+}}=5.00\pm0.10\,\rm{GeV}$
disfavor assigning the $X(4140)$ to be the $J^{PC}=1^{++}$ diquark-antidiquark
type $cs\bar{c}\bar{s}$ tetraquark state. Moreover, we obtain the masses of the
$J^{PC}=1^{+-}$ diquark-antidiquark type $cs\bar{c}\bar{s}$ tetraquark states
as a byproduct. The present predictions can be confronted to the experimental
data in the future.
|
[
{
"created": "Sun, 3 Jul 2016 23:49:11 GMT",
"version": "v1"
},
{
"created": "Tue, 9 Aug 2016 12:38:36 GMT",
"version": "v2"
},
{
"created": "Wed, 26 Oct 2016 02:04:56 GMT",
"version": "v3"
}
] |
2016-11-30
|
[
[
"Wang",
"Zhi-Gang",
""
]
] |
In this article, we take the $X(4140)$ as the diquark-antidiquark type $cs\bar{c}\bar{s}$ tetraquark state with $J^{PC}=1^{++}$, and study the mass and pole residue with the QCD sum rules in details by constructing two types interpolating currents. The numerical results $M_{X_{L,+}}=3.95\pm0.09\,\rm{GeV}$ and $M_{X_{H,+}}=5.00\pm0.10\,\rm{GeV}$ disfavor assigning the $X(4140)$ to be the $J^{PC}=1^{++}$ diquark-antidiquark type $cs\bar{c}\bar{s}$ tetraquark state. Moreover, we obtain the masses of the $J^{PC}=1^{+-}$ diquark-antidiquark type $cs\bar{c}\bar{s}$ tetraquark states as a byproduct. The present predictions can be confronted to the experimental data in the future.
|
1807.01453
|
Carlos Alvarado
|
Carlos Alvarado and Alfredo Aranda
|
Standard Model Extension with Flipped Generations
|
8 pages, 3 figures, 2 tables. Discussion on W' boson and RH neutrinos
extended, references added, typos corrected, title changed. Matches published
version in PLB
|
Phys. Lett. B 787 (2018) 1-7
|
10.1016/j.physletb.2018.10.047
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
An extension of the Standard Model is presented that leads to the possible
existence of new gauge bosons with masses in the range of a few TeV. Due to the
fact that their couplings to Standard Model fermions are strongly suppressed,
it is possible for them to be hidden from current searches. The model contains
additional generations of fermions with quantum numbers resembling those of the
Standard Model fermion generations but with a twist: their charge assignments
are such that their electric charges and chiralities are flipped with respect
to those of their corresponding Standard Model counterparts. This feature
provides a way to obtain potential dark matter candidates and the interesting
possibility for a Lepton number conserving dimension-five operator for Dirac
neutrino masses. The model implications associated to electroweak precision
parameters, flavor changing neutral currents, and diphoton rate contributions
are briefly discussed. The general assumptions of this set up are also used to
sketch a couple of variants of the model with peculiar features that could
motivate further study.
|
[
{
"created": "Wed, 4 Jul 2018 05:32:26 GMT",
"version": "v1"
},
{
"created": "Tue, 30 Oct 2018 07:37:00 GMT",
"version": "v2"
}
] |
2018-10-31
|
[
[
"Alvarado",
"Carlos",
""
],
[
"Aranda",
"Alfredo",
""
]
] |
An extension of the Standard Model is presented that leads to the possible existence of new gauge bosons with masses in the range of a few TeV. Due to the fact that their couplings to Standard Model fermions are strongly suppressed, it is possible for them to be hidden from current searches. The model contains additional generations of fermions with quantum numbers resembling those of the Standard Model fermion generations but with a twist: their charge assignments are such that their electric charges and chiralities are flipped with respect to those of their corresponding Standard Model counterparts. This feature provides a way to obtain potential dark matter candidates and the interesting possibility for a Lepton number conserving dimension-five operator for Dirac neutrino masses. The model implications associated to electroweak precision parameters, flavor changing neutral currents, and diphoton rate contributions are briefly discussed. The general assumptions of this set up are also used to sketch a couple of variants of the model with peculiar features that could motivate further study.
|
1602.04798
|
Daniel Nowakowski
|
Daniel Nowakowski and Stefano Carignano
|
Color-superconductivity and inhomogeneous chiral symmetry breaking in
isospin-asymmetric quark matter
|
14 pages and 7 figures. Contribution to the proceedings of Modern
Physics of Compact Stars 2015-Yerevan
| null | null | null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We investigate the effects of isospin asymmetry on the competition between
color-superconductivity and inhomogeneous chiral symmetry breaking in dense
two-flavor quark matter using an extended Nambu--Jona-Lasinio model. We confirm
the appearance of a coexistence window where chiral symmetry is inhomogeneously
broken and a nonzero spatially homogeneous diquark gap is present, consistently
with previous works, and show that such a phase survives at nonzero isospin
chemical potentials. We also discuss how the model phase structure becomes
modified as large isospin asymmetries are considered.
|
[
{
"created": "Mon, 15 Feb 2016 20:42:03 GMT",
"version": "v1"
}
] |
2016-02-16
|
[
[
"Nowakowski",
"Daniel",
""
],
[
"Carignano",
"Stefano",
""
]
] |
We investigate the effects of isospin asymmetry on the competition between color-superconductivity and inhomogeneous chiral symmetry breaking in dense two-flavor quark matter using an extended Nambu--Jona-Lasinio model. We confirm the appearance of a coexistence window where chiral symmetry is inhomogeneously broken and a nonzero spatially homogeneous diquark gap is present, consistently with previous works, and show that such a phase survives at nonzero isospin chemical potentials. We also discuss how the model phase structure becomes modified as large isospin asymmetries are considered.
|
hep-ph/9902245
|
G. Baur
|
Gerhard Baur and Albrecht Leuschner
|
Bethe-Heitler cross-section for very high photon energies and large muon
scattering angles
|
9 pages, 2 figures, to be published in Eur.Phys.J.C
|
Eur.Phys.J.C8:631-635,1999
|
10.1007/s100529900028
| null |
hep-ph
| null |
The cross-section for the process $\gamma + A \to \mu^+ + \mu^- + X$ is
studied where the photon energy is of the order of several hundreds of GeV and
where one of the leptons is scattered to large angles. This is of practical
importance for muon shielding calculations at future linear electron colliders.
In addition to the photon pole contribution which was previously considered
especially by Y.S.Tsai, we identify another component due to the muon pole
(equivalent photon and equivalent muon approximation). This is discussed
following the usual Bethe-Heitler formula. Then we give practically useful
formulae for inclusive lepton (muon) production along with some numerical
examples.
|
[
{
"created": "Fri, 5 Feb 1999 09:47:38 GMT",
"version": "v1"
}
] |
2011-09-13
|
[
[
"Baur",
"Gerhard",
""
],
[
"Leuschner",
"Albrecht",
""
]
] |
The cross-section for the process $\gamma + A \to \mu^+ + \mu^- + X$ is studied where the photon energy is of the order of several hundreds of GeV and where one of the leptons is scattered to large angles. This is of practical importance for muon shielding calculations at future linear electron colliders. In addition to the photon pole contribution which was previously considered especially by Y.S.Tsai, we identify another component due to the muon pole (equivalent photon and equivalent muon approximation). This is discussed following the usual Bethe-Heitler formula. Then we give practically useful formulae for inclusive lepton (muon) production along with some numerical examples.
|
0805.0760
|
Alexander E. Dorokhov
|
Alexander E. Dorokhov, Wojciech Broniowski
|
Pion pole light-by-light contribution to g-2 of the muon in a nonlocal
chiral quark model
|
15 pages, 7 figures
|
Phys.Rev.D78:073011,2008
|
10.1103/PhysRevD.78.073011
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We calculate the pion pole term of the light-by-light contribution to the
$g-2$ of the muon in the framework of an effective chiral quark model with
instanton-like nonlocal quark--quark interaction. The full kinematic dependence
of the pion-photon transition form factors is taken into account. The
dependence of form factors on the pion virtuality decreases the result by about
15% in comparison to the calculation where this dependence is neglected.
Further, it is demonstrated that the QCD constraints suggested by Melnikov and
Vainshtein are satisfied within the model. The corresponding contributions
originate from the box diagram as well from the pion-pole term. Our chiral
nonlocal model result for the pion-pole light-by-light contribution to
$(g-2)/2$ of the muon is $(6.3-6.7) \cdot10^{-10}$, which is in the ball park
of other effective-model calculations.
|
[
{
"created": "Tue, 6 May 2008 17:36:18 GMT",
"version": "v1"
},
{
"created": "Fri, 26 Sep 2008 05:59:47 GMT",
"version": "v2"
},
{
"created": "Mon, 13 Oct 2008 15:17:42 GMT",
"version": "v3"
}
] |
2008-11-26
|
[
[
"Dorokhov",
"Alexander E.",
""
],
[
"Broniowski",
"Wojciech",
""
]
] |
We calculate the pion pole term of the light-by-light contribution to the $g-2$ of the muon in the framework of an effective chiral quark model with instanton-like nonlocal quark--quark interaction. The full kinematic dependence of the pion-photon transition form factors is taken into account. The dependence of form factors on the pion virtuality decreases the result by about 15% in comparison to the calculation where this dependence is neglected. Further, it is demonstrated that the QCD constraints suggested by Melnikov and Vainshtein are satisfied within the model. The corresponding contributions originate from the box diagram as well from the pion-pole term. Our chiral nonlocal model result for the pion-pole light-by-light contribution to $(g-2)/2$ of the muon is $(6.3-6.7) \cdot10^{-10}$, which is in the ball park of other effective-model calculations.
|
hep-ph/0412283
|
Walter Grimus
|
W. Grimus, L. Lavoura
|
On a model with two zeros in the neutrino mass matrix
|
13 pages, no figures, plain LaTeX; one equation added, published
references updated, final version for J. Phys. G
|
J.Phys.G31:693-702,2005
|
10.1088/0954-3899/31/7/014
|
UWThPh-2004-35
|
hep-ph
| null |
We consider a Majorana neutrino mass matrix $\mathcal{M}_\nu$ with
$(\mathcal{M}_\nu)_{\mu\mu} = (\mathcal{M}_\nu)_{\tau\tau} = 0$, in the basis
where the charged-lepton mass matrix is diagonal. We show that this pattern for
the lepton mass matrices can be enforced by extending the Standard Model with
three scalar SU(2) triplets and by using a horizontal symmetry group
$\mathbbm{Z}_4$. The Ma--Sarkar (type-II seesaw) mechanism leads to very small
vacuum expectation values for the triplets, thus explaining the smallness of
the neutrino masses; at the same time, that mechanism renders the physical
scalars originating in the triplets very heavy. We show that the conditions
$(\mathcal{M}_\nu)_{\mu\mu} = (\mathcal{M}_\nu)_{\tau\tau} = 0$ allow both for
a normal neutrino mass spectrum and for an inverted one. In the first case, the
neutrino masses must be larger than $0.1 {eV}$ and the atmospheric mixing angle
$\theta_{23}$ must be practically equal to $45^\circ$. In the second case, the
product $\sin{\theta_{13}} | \tan{2 \theta_{23}} |$ must be of order one or
larger, thus correlating the large or maximal atmospheric neutrino mixing with
the smallness of the mixing angle $\theta_{13}$.
|
[
{
"created": "Mon, 20 Dec 2004 08:02:10 GMT",
"version": "v1"
},
{
"created": "Thu, 23 Dec 2004 07:54:18 GMT",
"version": "v2"
},
{
"created": "Wed, 20 Apr 2005 14:51:20 GMT",
"version": "v3"
}
] |
2011-07-19
|
[
[
"Grimus",
"W.",
""
],
[
"Lavoura",
"L.",
""
]
] |
We consider a Majorana neutrino mass matrix $\mathcal{M}_\nu$ with $(\mathcal{M}_\nu)_{\mu\mu} = (\mathcal{M}_\nu)_{\tau\tau} = 0$, in the basis where the charged-lepton mass matrix is diagonal. We show that this pattern for the lepton mass matrices can be enforced by extending the Standard Model with three scalar SU(2) triplets and by using a horizontal symmetry group $\mathbbm{Z}_4$. The Ma--Sarkar (type-II seesaw) mechanism leads to very small vacuum expectation values for the triplets, thus explaining the smallness of the neutrino masses; at the same time, that mechanism renders the physical scalars originating in the triplets very heavy. We show that the conditions $(\mathcal{M}_\nu)_{\mu\mu} = (\mathcal{M}_\nu)_{\tau\tau} = 0$ allow both for a normal neutrino mass spectrum and for an inverted one. In the first case, the neutrino masses must be larger than $0.1 {eV}$ and the atmospheric mixing angle $\theta_{23}$ must be practically equal to $45^\circ$. In the second case, the product $\sin{\theta_{13}} | \tan{2 \theta_{23}} |$ must be of order one or larger, thus correlating the large or maximal atmospheric neutrino mixing with the smallness of the mixing angle $\theta_{13}$.
|
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