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|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
hep-ph/9412254
|
PostDoc Its
|
Darwin Chang, Xiao-Gang He and Sandip Pakvasa
|
CP Violation In Hyperon Decays Due To Left-Right Mixing
|
11 pages, Revtex
|
Phys.Rev.Lett.74:3927-3930,1995
|
10.1103/PhysRevLett.74.3927
|
OITS-564, UH-511-810-94, NHCU-HEP-94-30
|
hep-ph
| null |
We consider CP violation due to left-right mixing in a class of Left-Right
symmetric models and show that it leads to observable effects in hyperon
decays. For S-wave, the contribution to CP violating asymmetry A of the
polarization in hyperon and anti-hyperon decays is proportional to
$\epsilon'/\epsilon$. While the tree level L-R operators contribution is
constrained to be less than $ 10^{-5}$, the gluon penguin operator contribution
can be as large as $10^{-4}$. For P-wave, the contribution is not directly
related to $\epsilon'/\epsilon$. Its contribution to A can be larger and may
reach $6\times 10^{-4}$ in $\Lambda \rightarrow p\pi^-$. This is much larger
than the value expected for A in the Standard Model.
|
[
{
"created": "Wed, 7 Dec 1994 18:59:33 GMT",
"version": "v1"
}
] |
2010-11-01
|
[
[
"Chang",
"Darwin",
""
],
[
"He",
"Xiao-Gang",
""
],
[
"Pakvasa",
"Sandip",
""
]
] |
We consider CP violation due to left-right mixing in a class of Left-Right symmetric models and show that it leads to observable effects in hyperon decays. For S-wave, the contribution to CP violating asymmetry A of the polarization in hyperon and anti-hyperon decays is proportional to $\epsilon'/\epsilon$. While the tree level L-R operators contribution is constrained to be less than $ 10^{-5}$, the gluon penguin operator contribution can be as large as $10^{-4}$. For P-wave, the contribution is not directly related to $\epsilon'/\epsilon$. Its contribution to A can be larger and may reach $6\times 10^{-4}$ in $\Lambda \rightarrow p\pi^-$. This is much larger than the value expected for A in the Standard Model.
|
2203.04561
|
Hai-Yang Cheng
|
Hai-Yang Cheng, Cheng-Wei Chiang, Zhi-Qing Zhang
|
Two- and three-body hadronic decays of charmed mesons involving a tensor
meson
|
18 pages
|
Phys. Rev. D 105, 093006 (2022)
|
10.1103/PhysRevD.105.093006
| null |
hep-ph hep-ex
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We study the quasi-two-body $D\to TP$ decays and the three-body $D$ decays
proceeding through intermediate tensor resonances, where $T$ and $P$ denote
tensor and pseudoscalar mesons, respectively. We employ $D\to T$ transition
form factors based upon light-cone sum rules and the covariant light-front
quark model to evaluate the decay rates, with the former giving a better
agreement with current data. Though the tree amplitudes with the emitted meson
being a tensor meson vanish under factorization approximation, contributions
proportional to the tensor decay constant $f_T$ can be produced from vertex and
hard spectator-scattering corrections. We also investigate the finite-width
effects of the tensor mesons and find that, contrary to three-body $B$ decays,
the tensor-mediated $D$ decays are more seriously affected and the narrow width
approximation has to be corrected. More experimental data are required in order
to extract information topological amplitudes associated with quasi-two-body
$D\to TP$ decays. Among the data, the $D^+\to f_2\pi^+$ and $D^+\to \bar
K_2^{*0}\pi^+$ branching fractions are not self consistent and further
clarification is called for.
|
[
{
"created": "Wed, 9 Mar 2022 07:47:38 GMT",
"version": "v1"
}
] |
2022-06-01
|
[
[
"Cheng",
"Hai-Yang",
""
],
[
"Chiang",
"Cheng-Wei",
""
],
[
"Zhang",
"Zhi-Qing",
""
]
] |
We study the quasi-two-body $D\to TP$ decays and the three-body $D$ decays proceeding through intermediate tensor resonances, where $T$ and $P$ denote tensor and pseudoscalar mesons, respectively. We employ $D\to T$ transition form factors based upon light-cone sum rules and the covariant light-front quark model to evaluate the decay rates, with the former giving a better agreement with current data. Though the tree amplitudes with the emitted meson being a tensor meson vanish under factorization approximation, contributions proportional to the tensor decay constant $f_T$ can be produced from vertex and hard spectator-scattering corrections. We also investigate the finite-width effects of the tensor mesons and find that, contrary to three-body $B$ decays, the tensor-mediated $D$ decays are more seriously affected and the narrow width approximation has to be corrected. More experimental data are required in order to extract information topological amplitudes associated with quasi-two-body $D\to TP$ decays. Among the data, the $D^+\to f_2\pi^+$ and $D^+\to \bar K_2^{*0}\pi^+$ branching fractions are not self consistent and further clarification is called for.
|
2308.01401
|
N\'estor Armesto
|
Tolga Altinoluk, N\'estor Armesto, Alexander Kovner, Michael Lublinsky
|
Single inclusive particle production in pA collisions at forward
rapidities: beyond the hybrid model
|
LaTeX, 7 pages, contribution to DIS2023: XXX International Workshop
on Deep-Inelastic Scattering and Related Subjects, Michigan State University,
USA, 27-31 March 2023
| null | null | null |
hep-ph nucl-th
|
http://creativecommons.org/licenses/by/4.0/
|
In this contribution we reconsider the calculation at next-to-leading order
of forward inclusive single hadron production in $pA$ collisions within the
hybrid approach. We conclude that the proper framework to compute this cross
section beyond leading order is not collinear factorization as assumed so far,
but the TMD factorized framework.
|
[
{
"created": "Wed, 2 Aug 2023 19:49:29 GMT",
"version": "v1"
}
] |
2023-08-04
|
[
[
"Altinoluk",
"Tolga",
""
],
[
"Armesto",
"Néstor",
""
],
[
"Kovner",
"Alexander",
""
],
[
"Lublinsky",
"Michael",
""
]
] |
In this contribution we reconsider the calculation at next-to-leading order of forward inclusive single hadron production in $pA$ collisions within the hybrid approach. We conclude that the proper framework to compute this cross section beyond leading order is not collinear factorization as assumed so far, but the TMD factorized framework.
|
hep-ph/9407381
|
Dam Thanh Son
|
M.V.Libanov, V.A.Rubakov, D.T.Son and S.V.Troitsky
|
Exponentiation of Multiparticle Amplitudes in Scalar Theories
|
Revtex 3.0, 45 pages, 11 figures (some requires bezier.sty, two
postscript figures appended after \end{document}), INR-866/94
|
Phys.Rev.D50:7553-7569,1994
|
10.1103/PhysRevD.50.7553
| null |
hep-ph
| null |
It is argued that the amplitudes of the production of $n$ soft scalar
particles by one or a few energetic ones in theories like $\lambda\phi^4$ has
the exponential form, $A_n\propto\sqrt{n!}\exp[{1\over\lambda}F(\lambda
n,\epsilon)]$, in the regime $\lambda\to 0$, $\lambda n={fixed}$,
$\epsilon={fixed}$, where $\epsilon$ is the typical kinetic energy of outgoing
particles. Existing results support this conjecture. Several new analytical and
numerical results in favor of the exponential behavior of multiparticle
amplitudes are presented.
|
[
{
"created": "Tue, 26 Jul 1994 17:13:40 GMT",
"version": "v1"
}
] |
2008-11-26
|
[
[
"Libanov",
"M. V.",
""
],
[
"Rubakov",
"V. A.",
""
],
[
"Son",
"D. T.",
""
],
[
"Troitsky",
"S. V.",
""
]
] |
It is argued that the amplitudes of the production of $n$ soft scalar particles by one or a few energetic ones in theories like $\lambda\phi^4$ has the exponential form, $A_n\propto\sqrt{n!}\exp[{1\over\lambda}F(\lambda n,\epsilon)]$, in the regime $\lambda\to 0$, $\lambda n={fixed}$, $\epsilon={fixed}$, where $\epsilon$ is the typical kinetic energy of outgoing particles. Existing results support this conjecture. Several new analytical and numerical results in favor of the exponential behavior of multiparticle amplitudes are presented.
|
2309.00132
|
Jae Kim
|
Jae Jun Kim
|
When a complementarity in the neutrino and the quark mixing meets a
parameter symmetry and its implications to the unitarity
| null | null | null | null |
hep-ph
|
http://creativecommons.org/licenses/by/4.0/
|
We present a complementarity that addresses relationships among the
parameters in the neutrino and the quark mixing matrix, use it to estimate the
size of the uncertainty among the elements in the matrix and address its
implications to the unitarity of the quark mixing matrix and Wolfenstein
parameterization and the tension in the first row. First, we describe how a
complementarity with a phase being introduced as an extra parameter can be held
in the nine independent schemes of parameterizing the matrix introducing a
discrete parameter symmetry within a certain size of uncertainty and how it can
be related to a combination of sine functions. With that, for the first time,
we describe a method that we can use to constrain the size of the uncertainty
associated with the parameters, not the central values, complementing that
among the diagonal elements in the neutrino mixing matrix. Then we do the same
for the quark sector and discuss its implication in the relation to the size of
the uncertainty among the elements. Seeing that our estimation is larger than
that was reported by running the global fit in the quark sector, our result
could be an indication that we may need to be cautious when addressing the
tension in the first row of the matrix in the quark sector and when running
global fit to constrain the size of the uncertainty, where Wolfenstein
parameterization, one that is not unitarity guaranteed, is used, as opposed to
the combination of the three rotational matrix. Given that the size of the
uncertainty for the individual diagonal element in the second and the third
row, our result also could be an indication that we may need to wait until the
size of uncertainty for the second and the third row goes down further before
addressing the tension. It could be an opening of considering the possibility
of a mixing between the neutrino and the quark sector too.
|
[
{
"created": "Thu, 31 Aug 2023 20:48:49 GMT",
"version": "v1"
},
{
"created": "Fri, 24 May 2024 18:53:14 GMT",
"version": "v2"
},
{
"created": "Fri, 12 Jul 2024 15:31:43 GMT",
"version": "v3"
}
] |
2024-07-15
|
[
[
"Kim",
"Jae Jun",
""
]
] |
We present a complementarity that addresses relationships among the parameters in the neutrino and the quark mixing matrix, use it to estimate the size of the uncertainty among the elements in the matrix and address its implications to the unitarity of the quark mixing matrix and Wolfenstein parameterization and the tension in the first row. First, we describe how a complementarity with a phase being introduced as an extra parameter can be held in the nine independent schemes of parameterizing the matrix introducing a discrete parameter symmetry within a certain size of uncertainty and how it can be related to a combination of sine functions. With that, for the first time, we describe a method that we can use to constrain the size of the uncertainty associated with the parameters, not the central values, complementing that among the diagonal elements in the neutrino mixing matrix. Then we do the same for the quark sector and discuss its implication in the relation to the size of the uncertainty among the elements. Seeing that our estimation is larger than that was reported by running the global fit in the quark sector, our result could be an indication that we may need to be cautious when addressing the tension in the first row of the matrix in the quark sector and when running global fit to constrain the size of the uncertainty, where Wolfenstein parameterization, one that is not unitarity guaranteed, is used, as opposed to the combination of the three rotational matrix. Given that the size of the uncertainty for the individual diagonal element in the second and the third row, our result also could be an indication that we may need to wait until the size of uncertainty for the second and the third row goes down further before addressing the tension. It could be an opening of considering the possibility of a mixing between the neutrino and the quark sector too.
|
1609.03955
|
Li Lin Yang
|
Yinqiang Gong, Zhao Li, Xiaofeng Xu, Li Lin Yang and Xiaoran Zhao
|
Mixed QCD-EW corrections for Higgs boson production at $e^+e^-$
colliders
|
Version published in Phys.Rev.D
|
Phys. Rev. D 95, 093003 (2017)
|
10.1103/PhysRevD.95.093003
|
CP3-16-54; MCnet-16-40
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Since the discovery of the Higgs boson at the Large Hadron Collider, a future
electron-position collider has been proposed for precisely studying its
properties. We investigate the production of the Higgs boson at such an
$e^+e^-$ collider associated with a $Z$ boson, and calculate for the first time
the mixed QCD-electroweak corrections to the total cross sections. We provide
an approximate analytic formula for the cross section and show that it
reproduces the exact numeric results rather well for collider energies up to
350 GeV. We also provide numeric results for $\sqrt{s}=500$ GeV, where the
approximate formula is no longer valid. We find that the
$\mathcal{O}(\alpha\alpha_s)$ corrections amount to a 1.3% increase of the
cross section for a center-of-mass energy around 240 GeV. This is significantly
larger than the expected experimental accuracy and has to be included for
extracting the properties of the Higgs boson from the measurements of the cross
sections in the future.
|
[
{
"created": "Tue, 13 Sep 2016 18:05:00 GMT",
"version": "v1"
},
{
"created": "Fri, 28 Oct 2016 04:56:20 GMT",
"version": "v2"
},
{
"created": "Tue, 5 Sep 2017 13:56:56 GMT",
"version": "v3"
}
] |
2017-09-06
|
[
[
"Gong",
"Yinqiang",
""
],
[
"Li",
"Zhao",
""
],
[
"Xu",
"Xiaofeng",
""
],
[
"Yang",
"Li Lin",
""
],
[
"Zhao",
"Xiaoran",
""
]
] |
Since the discovery of the Higgs boson at the Large Hadron Collider, a future electron-position collider has been proposed for precisely studying its properties. We investigate the production of the Higgs boson at such an $e^+e^-$ collider associated with a $Z$ boson, and calculate for the first time the mixed QCD-electroweak corrections to the total cross sections. We provide an approximate analytic formula for the cross section and show that it reproduces the exact numeric results rather well for collider energies up to 350 GeV. We also provide numeric results for $\sqrt{s}=500$ GeV, where the approximate formula is no longer valid. We find that the $\mathcal{O}(\alpha\alpha_s)$ corrections amount to a 1.3% increase of the cross section for a center-of-mass energy around 240 GeV. This is significantly larger than the expected experimental accuracy and has to be included for extracting the properties of the Higgs boson from the measurements of the cross sections in the future.
|
2212.12172
|
Peter Krachkov
|
P. A. Krachkov, A. I. Milstein, and N. Yu. Muchnoi
|
Resonant amplification of a relativistic electron bremsstrahlung on an
atom in the undulator field
|
5 pages, 2 figures
| null |
10.1016/j.physletb.2023.137756
| null |
hep-ph hep-ex physics.atom-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
It is shown that the influence of the undulator field on the motion of a
relativistic electron leads to a significant increase of the bremsstrahlung
cross section on an atom near the end of the spectrum of undulator radiation.
Observation of this effect is quite a realistic task.
|
[
{
"created": "Fri, 23 Dec 2022 06:58:11 GMT",
"version": "v1"
}
] |
2023-02-15
|
[
[
"Krachkov",
"P. A.",
""
],
[
"Milstein",
"A. I.",
""
],
[
"Muchnoi",
"N. Yu.",
""
]
] |
It is shown that the influence of the undulator field on the motion of a relativistic electron leads to a significant increase of the bremsstrahlung cross section on an atom near the end of the spectrum of undulator radiation. Observation of this effect is quite a realistic task.
|
hep-ph/0407079
|
Junpei Fujimoto
|
F. Boudjema (1), J. Fujimoto (2), T. Ishikawa (2), T. Kaneko (2),
K.Kato (3), Y. Kurihara (2), and Y. Shimizu (2) ((1) LAPTH, (2) KEK, (3)
Kogakuin Univ.)
|
Multi-leg calculations with the GRACE/1-LOOP system. --Toward Radiative
Corrections to e+e- -> mu nu-bar u d-bar --
|
5 pages,invited talk at "Loops & Legs in Quantum Field Theory 2004",
Zinnowitz, Germany, April 2004
| null |
10.1016/j.nuclphysbps.2004.09.016
| null |
hep-ph
| null |
We performed the calculation of the full O(alpha) corrections to e+e- -> mu-
nu-bar u d-bar with the help of the GRACE/1-LOOP system. We discuss how a
finite decay width introduces a serious gauge invariance breaking, particularly
for infrared 5-point functions. This is related to the way the reduction of
those functions is performed and to the treatment of the width in the
reduction.
|
[
{
"created": "Wed, 7 Jul 2004 04:19:27 GMT",
"version": "v1"
}
] |
2009-11-10
|
[
[
"Boudjema",
"F.",
""
],
[
"Fujimoto",
"J.",
""
],
[
"Ishikawa",
"T.",
""
],
[
"Kaneko",
"T.",
""
],
[
"Kato",
"K.",
""
],
[
"Kurihara",
"Y.",
""
],
[
"Shimizu",
"Y.",
""
]
] |
We performed the calculation of the full O(alpha) corrections to e+e- -> mu- nu-bar u d-bar with the help of the GRACE/1-LOOP system. We discuss how a finite decay width introduces a serious gauge invariance breaking, particularly for infrared 5-point functions. This is related to the way the reduction of those functions is performed and to the treatment of the width in the reduction.
|
2312.14052
|
Giorgio Arcadi
|
Giorgio Arcadi, Juan Carlos Criado, Abdelhak Djouadi
|
Iteration on the Higgs-portal for vector Dark Matter and its effective
field theory description
|
16 pages, 3 figures
| null | null | null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We reanalyze the effective field theory (EFT) approach for the scenario in
which the particles that account for the dark matter (DM) in the universe are
vector states that interact only through the Standard Model-like Higgs boson.
These DM particles are searched for in direct and indirect detection in
astrophysical experiments and in invisible Higgs decays at the LHC. The
constraints obtained in these two search types are complementary and
correlated. In recent years, it has been advocated that the EFT approach is
problematic for small DM mass and that it does not capture all the aspects of
vector DM; one should thus rather interpret the searches in ultraviolet
complete theories that are more realistic. In this note, we show that a more
appropriate definition of the EFT with the introduction of an effective New
Physics scale parameter, can encompass such issues. We illustrate this by
matching the EFT to two examples of ultraviolet completions for it: the U(1)
model with a dark photon and a model that was recently adopted by the LHC
experiments in which vector-like fermions generate an effective interaction
between the Higgs and the DM states at the one-loop level. Additionally, we
find that the region of parameter space that is relevant for DM phenomenology
is well inside the range of validity of the EFT. It thus provides a general
parametrization of the effects of any ultraviolet model in the regime under
exploration, making it the ideal framework for model-independent analyses of
the vector DM Higgs-portal.
|
[
{
"created": "Thu, 21 Dec 2023 17:20:12 GMT",
"version": "v1"
}
] |
2023-12-22
|
[
[
"Arcadi",
"Giorgio",
""
],
[
"Criado",
"Juan Carlos",
""
],
[
"Djouadi",
"Abdelhak",
""
]
] |
We reanalyze the effective field theory (EFT) approach for the scenario in which the particles that account for the dark matter (DM) in the universe are vector states that interact only through the Standard Model-like Higgs boson. These DM particles are searched for in direct and indirect detection in astrophysical experiments and in invisible Higgs decays at the LHC. The constraints obtained in these two search types are complementary and correlated. In recent years, it has been advocated that the EFT approach is problematic for small DM mass and that it does not capture all the aspects of vector DM; one should thus rather interpret the searches in ultraviolet complete theories that are more realistic. In this note, we show that a more appropriate definition of the EFT with the introduction of an effective New Physics scale parameter, can encompass such issues. We illustrate this by matching the EFT to two examples of ultraviolet completions for it: the U(1) model with a dark photon and a model that was recently adopted by the LHC experiments in which vector-like fermions generate an effective interaction between the Higgs and the DM states at the one-loop level. Additionally, we find that the region of parameter space that is relevant for DM phenomenology is well inside the range of validity of the EFT. It thus provides a general parametrization of the effects of any ultraviolet model in the regime under exploration, making it the ideal framework for model-independent analyses of the vector DM Higgs-portal.
|
2311.10145
|
A. Herrero-Brocal
|
Antonio Herrero-Brocal, Avelino Vicente
|
The majoron coupling to charged leptons
|
36 pages, 2 figures; v3: added leptoquark contributions, minor
corrections and new references, matches version accepted by JHEP
| null | null |
IFIC/23-49
|
hep-ph
|
http://creativecommons.org/licenses/by/4.0/
|
The particle spectrum of all Majorana neutrino mass models with spontaneous
violation of global lepton number include a Goldstone boson, the so-called
majoron. The presence of this massless pseudoscalar changes the phenomenology
dramatically. In this work we derive general analytical expressions for the
1-loop coupling of the majoron to charged leptons. These can be applied to any
model featuring a majoron that have a clear hierarchy of energy scales,
required for an expansion in powers of the low-energy scale to be valid. We
show how to use our general results by applying them to some example models,
finding full agreement with previous results in several popular scenarios and
deriving novel ones in other setups.
|
[
{
"created": "Thu, 16 Nov 2023 19:00:17 GMT",
"version": "v1"
},
{
"created": "Mon, 27 Nov 2023 16:32:04 GMT",
"version": "v2"
},
{
"created": "Tue, 26 Dec 2023 11:49:54 GMT",
"version": "v3"
},
{
"created": "Wed, 17 Jan 2024 10:17:36 GMT",
"version": "v4"
}
] |
2024-01-18
|
[
[
"Herrero-Brocal",
"Antonio",
""
],
[
"Vicente",
"Avelino",
""
]
] |
The particle spectrum of all Majorana neutrino mass models with spontaneous violation of global lepton number include a Goldstone boson, the so-called majoron. The presence of this massless pseudoscalar changes the phenomenology dramatically. In this work we derive general analytical expressions for the 1-loop coupling of the majoron to charged leptons. These can be applied to any model featuring a majoron that have a clear hierarchy of energy scales, required for an expansion in powers of the low-energy scale to be valid. We show how to use our general results by applying them to some example models, finding full agreement with previous results in several popular scenarios and deriving novel ones in other setups.
|
hep-ph/9608385
| null |
L.Micu
|
The decay constants of pseudoscalar mesons in a relativistic quark model
|
11 pages, LaTex
|
Phys.Rev. D55 (1997) 4151-4156
|
10.1103/PhysRevD.55.4151
|
FT-417-1996
|
hep-ph
| null |
The decay constants of pseudoscalar mesons are calculated in a relativistic
quark model which assumes that mesons are made of a valence quark antiquark
pair and of an effective vacuum like component. The results are given in terms
of quark masses and of some free parameters entering the expression of the
internal wave functions of the mesons. By using the pion and kaon decay
constants $F_{\pi^+}=130.7~MeV,~F_{K^+}=159.8~MeV$ to fix the parameters of the
model one gets $60~MeV\leq F_{D^+}\leq 185~MeV,~95~MeV\leq
F_{D_s}\leq230~MeV,~80~MeV\leq F_{B^+}\leq205~MeV$ for the light quark masses
$m_u=5.1~MeV,~m_d=9.3~MeV,~m_s=175~MeV$ and the heavy quark masses in the
range: $1.~GeV\leq m_c\leq1.6~GeV,~4.1~GeV\leq m_b\leq4.5~GeV$. In the case of
light neutral mesons one obtains with the same set of parameters
$F_{\pi^0}\approx 138~MeV,~F_\eta\approx~130~MeV,F_{\eta'} \approx~78~MeV$. The
values are in agreement with the experimental data and other theoretical
results.
|
[
{
"created": "Tue, 20 Aug 1996 10:56:31 GMT",
"version": "v1"
}
] |
2009-10-28
|
[
[
"Micu",
"L.",
""
]
] |
The decay constants of pseudoscalar mesons are calculated in a relativistic quark model which assumes that mesons are made of a valence quark antiquark pair and of an effective vacuum like component. The results are given in terms of quark masses and of some free parameters entering the expression of the internal wave functions of the mesons. By using the pion and kaon decay constants $F_{\pi^+}=130.7~MeV,~F_{K^+}=159.8~MeV$ to fix the parameters of the model one gets $60~MeV\leq F_{D^+}\leq 185~MeV,~95~MeV\leq F_{D_s}\leq230~MeV,~80~MeV\leq F_{B^+}\leq205~MeV$ for the light quark masses $m_u=5.1~MeV,~m_d=9.3~MeV,~m_s=175~MeV$ and the heavy quark masses in the range: $1.~GeV\leq m_c\leq1.6~GeV,~4.1~GeV\leq m_b\leq4.5~GeV$. In the case of light neutral mesons one obtains with the same set of parameters $F_{\pi^0}\approx 138~MeV,~F_\eta\approx~130~MeV,F_{\eta'} \approx~78~MeV$. The values are in agreement with the experimental data and other theoretical results.
|
hep-ph/9501404
|
Stefan Dittmaier
|
S. Dittmaier, M. Kuroda, and D. Schildknecht
|
Refined Analysis of the Electroweak Precision Data
|
28 pages latex, 9 figures in uuencoded form, trivial misprint
corrected
|
Nucl.Phys.B448:3-29,1995
|
10.1016/0550-3213(95)00219-I
|
BI-TP 94/62
|
hep-ph
| null |
We refine our recent analysis of the electroweak precision data at the \PZO\
pole by including the hadronic decay modes of the \PZO. Within the framework of
an effective Lagrangian we parametrize $SU(2)$ violation by the additional
process-specific parameters $\De y_\nu$, $\De\yh$, and $\De\yb$ (for the
$\PZO\nu\bar\nu$, $\PZO\Pq\bar\Pq$, and $\PZO\Pb\bar\Pb$ vertices) together
with the previously introduced parameters $\De x$, $\De y$, and $\eps$. We find
that a six-parameter analysis of the experimental data is indeed feasible, and
it is carried out in addition to a four-parameter fit for $\De x$, $\De y$,
$\eps$, and $\De\yb$ only. We reemphasize that the experimental data have
become sensitive to the (combined) magnitude of the vertex corrections at the
$\PWp\Pl\bar\nu$ ($\PWm\nu\bar\Pl$) and $\PZO\Pl\bar\Pl$ vertices, $\De y$,
which is insensitive to the notion of the Higgs mechanism but dependent on the
non-Abelian, trilinear vector-boson coupling. Full explicit analytical results
for the standard one-loop predictions for the above-mentioned parameters are
given, and the leading two-loop top-quark effects are included. The analytic
formluae for the analysis of the experimental data in terms of the parameters
$\De x$, $\De y$ etc.\ are presented in order to encourage experimentalists to
persue such an analysis by themselves with future data.
|
[
{
"created": "Mon, 30 Jan 1995 15:29:21 GMT",
"version": "v1"
},
{
"created": "Mon, 6 Feb 1995 16:24:40 GMT",
"version": "v2"
},
{
"created": "Thu, 2 Mar 1995 17:30:30 GMT",
"version": "v3"
}
] |
2010-11-01
|
[
[
"Dittmaier",
"S.",
""
],
[
"Kuroda",
"M.",
""
],
[
"Schildknecht",
"D.",
""
]
] |
We refine our recent analysis of the electroweak precision data at the \PZO\ pole by including the hadronic decay modes of the \PZO. Within the framework of an effective Lagrangian we parametrize $SU(2)$ violation by the additional process-specific parameters $\De y_\nu$, $\De\yh$, and $\De\yb$ (for the $\PZO\nu\bar\nu$, $\PZO\Pq\bar\Pq$, and $\PZO\Pb\bar\Pb$ vertices) together with the previously introduced parameters $\De x$, $\De y$, and $\eps$. We find that a six-parameter analysis of the experimental data is indeed feasible, and it is carried out in addition to a four-parameter fit for $\De x$, $\De y$, $\eps$, and $\De\yb$ only. We reemphasize that the experimental data have become sensitive to the (combined) magnitude of the vertex corrections at the $\PWp\Pl\bar\nu$ ($\PWm\nu\bar\Pl$) and $\PZO\Pl\bar\Pl$ vertices, $\De y$, which is insensitive to the notion of the Higgs mechanism but dependent on the non-Abelian, trilinear vector-boson coupling. Full explicit analytical results for the standard one-loop predictions for the above-mentioned parameters are given, and the leading two-loop top-quark effects are included. The analytic formluae for the analysis of the experimental data in terms of the parameters $\De x$, $\De y$ etc.\ are presented in order to encourage experimentalists to persue such an analysis by themselves with future data.
|
hep-ph/0112060
|
Orlando L. G. Peres
|
A. M. Gago, M. M. Guzzo, P. C. de Holanda, H. Nunokawa, O. L. G.
Peres, V. Pleitez and R. Zukanovich Funchal
|
Global Analysis of the post-SNO Solar Neutrino Data for Standard and
Non-Standard Oscillation Mechanisms
|
Minor changes in the solar magnetic field profile used, and some
refferences added. Final version to appear in PRD
|
Phys.Rev. D65 (2002) 073012
|
10.1103/PhysRevD.65.073012
| null |
hep-ph astro-ph hep-ex
| null |
What can we learn from solar neutrino observations? Is there any solution to
the solar neutrino anomaly which is favored by the present experimental
panorama? After SNO results, is it possible to affirm that neutrinos have mass?
In order to answer such questions we analyze the current available data from
the solar neutrino experiments, including the recent SNO result, in view of
many acceptable solutions to the solar neutrino problem based on different
conversion mechanisms, for the first time, using the same statistical
procedure. This allows us to do a direct comparison of the goodness of the fit
among different solutions, from which we can discuss and conclude on the
current status of each proposed dynamical mechanism. These solutions are based
on different assumptions: (a) neutrino mass and mixing, (b) non-vanishing
neutrino magnetic moment, (c) the existence of non-standard flavor-changing and
non-universal neutrino interactions and (d) the tiny violation of the
equivalence principle. We investigate the quality of the fit provided by each
one of these solutions not only to the total rate measured by all the solar
neutrino experiments but also to the recoil electron energy spectrum measured
at different zenith angles by the Super-Kamiokande collaboration. We conclude
that several non-standard neutrino flavor conversion mechanisms provide a very
good fit to the experimental data which is comparable with (or even slightly
better than) the most famous solution to the solar neutrino anomaly based on
the neutrino oscillation induced by mass.
|
[
{
"created": "Tue, 4 Dec 2001 21:00:09 GMT",
"version": "v1"
},
{
"created": "Thu, 21 Mar 2002 09:07:34 GMT",
"version": "v2"
}
] |
2009-11-07
|
[
[
"Gago",
"A. M.",
""
],
[
"Guzzo",
"M. M.",
""
],
[
"de Holanda",
"P. C.",
""
],
[
"Nunokawa",
"H.",
""
],
[
"Peres",
"O. L. G.",
""
],
[
"Pleitez",
"V.",
""
],
[
"Funchal",
"R. Zukanovich",
""
]
] |
What can we learn from solar neutrino observations? Is there any solution to the solar neutrino anomaly which is favored by the present experimental panorama? After SNO results, is it possible to affirm that neutrinos have mass? In order to answer such questions we analyze the current available data from the solar neutrino experiments, including the recent SNO result, in view of many acceptable solutions to the solar neutrino problem based on different conversion mechanisms, for the first time, using the same statistical procedure. This allows us to do a direct comparison of the goodness of the fit among different solutions, from which we can discuss and conclude on the current status of each proposed dynamical mechanism. These solutions are based on different assumptions: (a) neutrino mass and mixing, (b) non-vanishing neutrino magnetic moment, (c) the existence of non-standard flavor-changing and non-universal neutrino interactions and (d) the tiny violation of the equivalence principle. We investigate the quality of the fit provided by each one of these solutions not only to the total rate measured by all the solar neutrino experiments but also to the recoil electron energy spectrum measured at different zenith angles by the Super-Kamiokande collaboration. We conclude that several non-standard neutrino flavor conversion mechanisms provide a very good fit to the experimental data which is comparable with (or even slightly better than) the most famous solution to the solar neutrino anomaly based on the neutrino oscillation induced by mass.
|
1409.6311
|
Aurel Schneider
|
Alexander Merle and Aurel Schneider
|
Production of Sterile Neutrino Dark Matter and the 3.5 keV line
|
Appendix added; slight change in distribution function, main results
not affected
| null |
10.1016/j.physletb.2015.07.080
|
MPP--2014--348
|
hep-ph astro-ph.CO
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The recent observation of an X-ray line at an energy of 3.5 keV mainly from
galaxy clusters has initiated a discussion about whether we may have seen a
possible dark matter signal. If confirmed, this signal could stem from a
decaying sterile neutrino of a mass of 7.1 keV. Such a particle could make up
all the dark matter, but it is not clear how it was produced in the early
Universe. In this letter we show that it is possible to discriminate between
different production mechanisms with present-day astronomical data. The most
stringent constraint comes from the Lyman-{\alpha} forest and seems to disfavor
all but one of the main production mechanisms proposed in the literature, which
is the production via decay of heavy scalar singlets. Pinning down the
production mechanism will help to decide whether the X-ray signal indeed
comprises an indirect detection of dark matter.
|
[
{
"created": "Mon, 22 Sep 2014 20:00:15 GMT",
"version": "v1"
},
{
"created": "Wed, 11 Feb 2015 14:23:30 GMT",
"version": "v2"
}
] |
2015-09-30
|
[
[
"Merle",
"Alexander",
""
],
[
"Schneider",
"Aurel",
""
]
] |
The recent observation of an X-ray line at an energy of 3.5 keV mainly from galaxy clusters has initiated a discussion about whether we may have seen a possible dark matter signal. If confirmed, this signal could stem from a decaying sterile neutrino of a mass of 7.1 keV. Such a particle could make up all the dark matter, but it is not clear how it was produced in the early Universe. In this letter we show that it is possible to discriminate between different production mechanisms with present-day astronomical data. The most stringent constraint comes from the Lyman-{\alpha} forest and seems to disfavor all but one of the main production mechanisms proposed in the literature, which is the production via decay of heavy scalar singlets. Pinning down the production mechanism will help to decide whether the X-ray signal indeed comprises an indirect detection of dark matter.
|
1005.1882
|
Xiong Wei Liu
|
Zhao Zhang, Teiji Kunihiro
|
Multiple critical point structure for chiral phase transition induced by
charge neutrality and vector interaction
|
9 pages, 1 table, 1 figure. To appear in Proceedings for "Compact
stars in the QCD phase diagram II (CSQCD II), May 20-24, 2009, KIAA at Peking
University, Beijing - P. R. China [http://vega.bac.pku.edu.cn/rxxu/csqcd.htm]
| null | null | null |
hep-ph astro-ph.SR
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The combined effect of the repulsive vector interaction and the positive
electric chemical potential on the chiral phase transition is investigated by
considering neutral color superconductivity. Under the charge-neutrality
constraint, the chiral condensate, diquark condensate and quark number
densities are obtained in two-plus-one-flavor Nambu-Jona-Lasinio model with the
so called Kobayashi-Maskawa-'t Hooft term. We demonstrate that multiple chiral
critical-point structures always exist in the Nambu-Jona-Lasinio model within
the self-consistent mean-field approximation, and that the number of chiral
critical points can vary from zero to four, which is dependent on the
magnitudes of vector interaction and the diquark coupling.
|
[
{
"created": "Tue, 11 May 2010 16:33:13 GMT",
"version": "v1"
},
{
"created": "Wed, 19 Jan 2011 11:29:05 GMT",
"version": "v2"
}
] |
2011-01-20
|
[
[
"Zhang",
"Zhao",
""
],
[
"Kunihiro",
"Teiji",
""
]
] |
The combined effect of the repulsive vector interaction and the positive electric chemical potential on the chiral phase transition is investigated by considering neutral color superconductivity. Under the charge-neutrality constraint, the chiral condensate, diquark condensate and quark number densities are obtained in two-plus-one-flavor Nambu-Jona-Lasinio model with the so called Kobayashi-Maskawa-'t Hooft term. We demonstrate that multiple chiral critical-point structures always exist in the Nambu-Jona-Lasinio model within the self-consistent mean-field approximation, and that the number of chiral critical points can vary from zero to four, which is dependent on the magnitudes of vector interaction and the diquark coupling.
|
hep-ph/0404111
|
Sven-Olaf Moch
|
A. Vogt, S. Moch and J.A.M. Vermaseren
|
The Three-Loop Splitting Functions in QCD: The Singlet Case
|
41 pages, Latex, 12 figures
|
Nucl.Phys. B691 (2004) 129-181
|
10.1016/j.nuclphysb.2004.04.024
|
NIKHEF 04-004, DESY 04-060, SFB/CPP-04-12
|
hep-ph
| null |
We compute the next-to-next-to-leading order (NNLO) contributions to the
splitting functions governing the evolution of the unpolarized flavour-singlet
parton densities in perturbative QCD. The exact expressions are presented in
both Mellin-N and Bjorken-x space. We also provide accurate parametrizations
for practical applications. Our results agree with all partial results
available in the literature. As in the non-singlet case, the correct leading
logarithmic predictions for small momentum fractions x do not provide good
estimates of the respective complete splitting functions. We investigate the
size of the corrections and the stability of the NNLO evolution under variation
of the renormalization scale. The perturbative expansion appears to converge
rapidly at x >~ 10^-3. Relatively large third-order corrections are found at
smaller values of x.
|
[
{
"created": "Wed, 14 Apr 2004 07:02:13 GMT",
"version": "v1"
}
] |
2010-04-05
|
[
[
"Vogt",
"A.",
""
],
[
"Moch",
"S.",
""
],
[
"Vermaseren",
"J. A. M.",
""
]
] |
We compute the next-to-next-to-leading order (NNLO) contributions to the splitting functions governing the evolution of the unpolarized flavour-singlet parton densities in perturbative QCD. The exact expressions are presented in both Mellin-N and Bjorken-x space. We also provide accurate parametrizations for practical applications. Our results agree with all partial results available in the literature. As in the non-singlet case, the correct leading logarithmic predictions for small momentum fractions x do not provide good estimates of the respective complete splitting functions. We investigate the size of the corrections and the stability of the NNLO evolution under variation of the renormalization scale. The perturbative expansion appears to converge rapidly at x >~ 10^-3. Relatively large third-order corrections are found at smaller values of x.
|
0808.2462
|
Josef Pradler
|
Josef Pradler, Frank Daniel Steffen
|
Thermal relic abundances of long-lived staus
|
34 pages, 8 figures; one reference added; matches published version
|
Nucl.Phys.B809:318-346,2009
|
10.1016/j.nuclphysb.2008.10.009
|
MPP-2008-107
|
hep-ph astro-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
In supersymmetric models with a long-lived stau being the lightest Standard
Model superpartner, the stau abundance during primordial nucleosynthesis is
tightly constrained. Considering the complete set of stau annihilation channels
in the minimal supersymmetric Standard Model (MSSM) with real parameters for
scenarios in which sparticle coannihilations are negligible, we calculate the
decoupling of the lighter stau from the primordial plasma and identify
processes which are capable to deplete the resulting stau abundance
significantly. We find particularly efficient stau annihilation at the
resonance of the heavy CP-even Higgs boson and for a lighter stau with a
sizeable left-right mixing due to enhanced stau-Higgs couplings. Even within
the constrained MSSM, we encounter both effects leading to exceptionally small
values of the resulting stau abundance. Prospects for collider phenomenology
are discussed and possible implications of our findings are addressed with
emphasis on gravitino dark matter scenarios.
|
[
{
"created": "Mon, 18 Aug 2008 19:58:21 GMT",
"version": "v1"
},
{
"created": "Thu, 28 Aug 2008 19:16:36 GMT",
"version": "v2"
},
{
"created": "Wed, 22 Oct 2008 18:21:09 GMT",
"version": "v3"
}
] |
2010-04-05
|
[
[
"Pradler",
"Josef",
""
],
[
"Steffen",
"Frank Daniel",
""
]
] |
In supersymmetric models with a long-lived stau being the lightest Standard Model superpartner, the stau abundance during primordial nucleosynthesis is tightly constrained. Considering the complete set of stau annihilation channels in the minimal supersymmetric Standard Model (MSSM) with real parameters for scenarios in which sparticle coannihilations are negligible, we calculate the decoupling of the lighter stau from the primordial plasma and identify processes which are capable to deplete the resulting stau abundance significantly. We find particularly efficient stau annihilation at the resonance of the heavy CP-even Higgs boson and for a lighter stau with a sizeable left-right mixing due to enhanced stau-Higgs couplings. Even within the constrained MSSM, we encounter both effects leading to exceptionally small values of the resulting stau abundance. Prospects for collider phenomenology are discussed and possible implications of our findings are addressed with emphasis on gravitino dark matter scenarios.
|
1512.03978
|
Andrea Donini
|
A. Donini
|
A scalar field coupled to a brane in ${\cal M}_4 \times {\cal S}_1$.
Part I: Kaluza-Klein spectrum and zero-mode localization
|
Replaced version with significant changes: shorter introduction;
computation of the exact spectrum with BLKT; KK-decomposition of the model
when a self-interaction is added. 32 pages, 7 pdf figures
| null | null |
IFIC 15-90
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
A toy model where a massless, real, scalar field $\Phi$ in a compact
space-time ${\cal M}_4 \times {\cal S}_1$ is coupled to a brane (parametrized
as a $\delta$-function) through the unique relevant operator $\delta (y) \Phi^2
(x,y)$ is considered. The exact Kaluza-Klein spectrum of the model is computed
for any value of the coupling between field and brane using the
Burniston-Siewert method to solve analytically transcendental equations. The
exact KK-spectrum of a model with a Brane-Localized Kinetic Term is also
computed. Weak- and strong-coupling limits are derived, matching or extending
mathematically equivalent existing results. For a negative coupling, the
would-be zero-mode $\psi_{0^-}^e$ is found to localize into the brane, behaving
as an effective four-dimensional field. The 4-dimensional KK-decomposition of
the model once a renormalizable cubic self-interaction $\Phi^3 (x,y)$ is added
to the action is derived computing the overlaps between the KK-modes. It is
found that the localized would-be zero-mode $\psi_{0^-}^e$ decouples from the
massive KK-spectrum in the limit of large brane-to-bulk coupling.
|
[
{
"created": "Sat, 12 Dec 2015 23:46:46 GMT",
"version": "v1"
},
{
"created": "Fri, 2 Dec 2016 12:03:05 GMT",
"version": "v2"
}
] |
2016-12-05
|
[
[
"Donini",
"A.",
""
]
] |
A toy model where a massless, real, scalar field $\Phi$ in a compact space-time ${\cal M}_4 \times {\cal S}_1$ is coupled to a brane (parametrized as a $\delta$-function) through the unique relevant operator $\delta (y) \Phi^2 (x,y)$ is considered. The exact Kaluza-Klein spectrum of the model is computed for any value of the coupling between field and brane using the Burniston-Siewert method to solve analytically transcendental equations. The exact KK-spectrum of a model with a Brane-Localized Kinetic Term is also computed. Weak- and strong-coupling limits are derived, matching or extending mathematically equivalent existing results. For a negative coupling, the would-be zero-mode $\psi_{0^-}^e$ is found to localize into the brane, behaving as an effective four-dimensional field. The 4-dimensional KK-decomposition of the model once a renormalizable cubic self-interaction $\Phi^3 (x,y)$ is added to the action is derived computing the overlaps between the KK-modes. It is found that the localized would-be zero-mode $\psi_{0^-}^e$ decouples from the massive KK-spectrum in the limit of large brane-to-bulk coupling.
|
1810.02588
|
Joel Oredsson
|
Joel Oredsson, Johan Rathsman
|
$Z_2$ breaking effects in 2-loop RG evolution of 2HDM
|
33 pages, journal version
| null |
10.1007/JHEP02(2019)152
|
LU TP 18-31
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We investigate the effects of a $Z_2$ symmetry in the CP-conserving
Two-Higgs-Doublet-Model (2HDM); which is often imposed to prevent
Flavor-Changing-Neutral-Currents (FCNCs) at tree-level. Specifically, we
analyze how a breaking of the $Z_2$ symmetry spreads during renormalization
group evolution; employing general 2-loop renormalization group equations that
we have derived. Evolving the model from the electroweak to the Planck scale,
we find that while the case of an exact $Z_2$ symmetric 2HDM is very
constrained, a soft breaking of the $Z_2$ symmetry extends the valid parameter
space regions. The effects of a hard $Z_2$ breaking in the scalar sector as
well as the stability of the flavor alignment ansatz are also investigated. We
find that while a hard breaking of the $Z_2$ symmetry in the potential is
problematic, since it speeds up the growth of quartic couplings, the generated
FCNCs are heavily suppressed. Conversely, we also find that hard $Z_2$ breaking
in the Yukawa sector at most gives moderate $Z_2$ breaking in the potential;
whereas the FCNCs can become quite sizable far away from the $Z_2$ symmetric
regions.
|
[
{
"created": "Fri, 5 Oct 2018 09:53:38 GMT",
"version": "v1"
},
{
"created": "Thu, 7 Mar 2019 16:41:38 GMT",
"version": "v2"
}
] |
2019-03-27
|
[
[
"Oredsson",
"Joel",
""
],
[
"Rathsman",
"Johan",
""
]
] |
We investigate the effects of a $Z_2$ symmetry in the CP-conserving Two-Higgs-Doublet-Model (2HDM); which is often imposed to prevent Flavor-Changing-Neutral-Currents (FCNCs) at tree-level. Specifically, we analyze how a breaking of the $Z_2$ symmetry spreads during renormalization group evolution; employing general 2-loop renormalization group equations that we have derived. Evolving the model from the electroweak to the Planck scale, we find that while the case of an exact $Z_2$ symmetric 2HDM is very constrained, a soft breaking of the $Z_2$ symmetry extends the valid parameter space regions. The effects of a hard $Z_2$ breaking in the scalar sector as well as the stability of the flavor alignment ansatz are also investigated. We find that while a hard breaking of the $Z_2$ symmetry in the potential is problematic, since it speeds up the growth of quartic couplings, the generated FCNCs are heavily suppressed. Conversely, we also find that hard $Z_2$ breaking in the Yukawa sector at most gives moderate $Z_2$ breaking in the potential; whereas the FCNCs can become quite sizable far away from the $Z_2$ symmetric regions.
|
hep-ph/9901206
|
Apostolos Pilaftsis
|
Apostolos Pilaftsis
|
Radiatively Induced Neutrino Masses and Large Higgs-Neutrino Couplings
in the Standard Model with Majorana Fields
|
Making the text of an old paper electronically available
|
Z.Phys. C55 (1992) 275-282
|
10.1007/BF01482590
| null |
hep-ph
| null |
The Higgs sector of the Standard Model with one right-handed neutrino per
family is systematically analyzed. In a model with intergenerational
independent mixings between families, we can account for very light neutrinos
acquiring Majorana masses radiatively at the first electroweak loop level. We
also find that in such a scenario the Higgs coupling to the light-heavy
neutrinos and to the heavy-heavy ones may be remarkably enhanced with
significant implications for the production of these heavy neutrinos at high
energy colliders.
|
[
{
"created": "Sat, 2 Jan 1999 15:30:04 GMT",
"version": "v1"
}
] |
2015-06-25
|
[
[
"Pilaftsis",
"Apostolos",
""
]
] |
The Higgs sector of the Standard Model with one right-handed neutrino per family is systematically analyzed. In a model with intergenerational independent mixings between families, we can account for very light neutrinos acquiring Majorana masses radiatively at the first electroweak loop level. We also find that in such a scenario the Higgs coupling to the light-heavy neutrinos and to the heavy-heavy ones may be remarkably enhanced with significant implications for the production of these heavy neutrinos at high energy colliders.
|
hep-ph/0308302
|
Yu Jia
|
Yu Jia (Michigan State U.)
|
Heavy-quark recombination in Z^0 decay
|
4 pages, 2 figures, prepared for CIPANP2003: Conference on the
Intersections of Particle and Nuclear Physics, New York City, May 19-24, 2003
| null |
10.1063/1.1664279
| null |
hep-ph
| null |
We briefly review the recent advances of heavy-quark recombination mechanism.
This mechanism predicts a class of power-suppressed 3-jet events in $Z^0$
decay, such as $b\bar{b}q$ and $b\bar{b}\bar{q}$. Furthermore, heavy quark
fragmentation function also receives a contribution from this mechanism. Some
light can be shed on the scaling of the maximum of the fragmentation function
for S-wave heavy hadrons. We finally comment on a new variant of this mechanism
which has important impact on the precision electroweak physics.
|
[
{
"created": "Thu, 28 Aug 2003 18:39:02 GMT",
"version": "v1"
}
] |
2009-11-10
|
[
[
"Jia",
"Yu",
"",
"Michigan State U."
]
] |
We briefly review the recent advances of heavy-quark recombination mechanism. This mechanism predicts a class of power-suppressed 3-jet events in $Z^0$ decay, such as $b\bar{b}q$ and $b\bar{b}\bar{q}$. Furthermore, heavy quark fragmentation function also receives a contribution from this mechanism. Some light can be shed on the scaling of the maximum of the fragmentation function for S-wave heavy hadrons. We finally comment on a new variant of this mechanism which has important impact on the precision electroweak physics.
|
1508.06640
|
Doojin Kim
|
Doojin Kim, Jong-Chul Park
|
An alternative interpretation for cosmic ray peaks
|
9 pages, 3 figures
| null |
10.1016/j.physletb.2015.09.070
|
CETUP2015-019
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We propose an alternative mechanism based upon dark matter (DM)
interpretation for anomalous peak signatures in cosmic ray measurements,
assuming an extended dark sector with two DM species. This is contrasted with
previous effort to explain various line-like cosmic-ray excesses in the context
of DM models where the relevant DM candidate directly annihilates into Standard
Model (SM) particles. The heavier DM is assumed to annihilate to an on-shell
intermediate state. As the simplest choice, it decays directly into the lighter
DM along with an unstable particle which in turn decays to a pair of SM states
corresponding to the interesting cosmic anomaly. We show that a sharp continuum
energy peak can be readily generated under the proposed DM scenario, depending
on dark sector particle mass spectra. Remarkably, such a peak is robustly
identified as half the mass of the unstable particle. Furthermore, other
underlying mass parameters are analytically related to the shape of energy
spectrum. We apply this idea to the two well-known line excesses in the cosmic
photon spectrum: 130 GeV gamma-ray line and 3.5 keV X-ray line. Each observed
peak spectrum is well-reproduced by theoretical expectation predicated upon our
suggested mechanism, and moreover, our resulting best fits provide rather
improved chi-square values.
|
[
{
"created": "Wed, 26 Aug 2015 20:09:56 GMT",
"version": "v1"
}
] |
2015-10-07
|
[
[
"Kim",
"Doojin",
""
],
[
"Park",
"Jong-Chul",
""
]
] |
We propose an alternative mechanism based upon dark matter (DM) interpretation for anomalous peak signatures in cosmic ray measurements, assuming an extended dark sector with two DM species. This is contrasted with previous effort to explain various line-like cosmic-ray excesses in the context of DM models where the relevant DM candidate directly annihilates into Standard Model (SM) particles. The heavier DM is assumed to annihilate to an on-shell intermediate state. As the simplest choice, it decays directly into the lighter DM along with an unstable particle which in turn decays to a pair of SM states corresponding to the interesting cosmic anomaly. We show that a sharp continuum energy peak can be readily generated under the proposed DM scenario, depending on dark sector particle mass spectra. Remarkably, such a peak is robustly identified as half the mass of the unstable particle. Furthermore, other underlying mass parameters are analytically related to the shape of energy spectrum. We apply this idea to the two well-known line excesses in the cosmic photon spectrum: 130 GeV gamma-ray line and 3.5 keV X-ray line. Each observed peak spectrum is well-reproduced by theoretical expectation predicated upon our suggested mechanism, and moreover, our resulting best fits provide rather improved chi-square values.
|
2405.02899
|
Mohammed Boukidi
|
Rachid Benbrik (1), Mohammed Boukidi (1), Stefano Moretti (2) (3) ((1)
Polydisciplinary Faculty, Laboratory of Fundamental and Applied Physics, Cadi
Ayyad University, Sidi Bouzid, Safi, Morocco, (2) School of Physics and
Astronomy, University of Southampton, United Kingdom, (3) Department of
Physics and Astronomy, Uppsala University, Uppsala, Sweden)
|
Superposition of CP-Even and CP-Odd Higgs Resonances: Explaining the 95
GeV Excesses within a Two-Higgs Doublet Model
|
10 pages, 7 figures. arXiv admin note: text overlap with
arXiv:2306.09029
| null | null | null |
hep-ph
|
http://creativecommons.org/licenses/by/4.0/
|
We propose an explanation for the observed excesses around 95 GeV in the
di-photon and di-tau invariant mass distributions, as reported by the CMS
collaboration at the Large Hadron Collider (LHC). These findings are
complemented by a long-standing discrepancy in the $b\bar{b}$ invariant mass at
the Large Electron-Positron (LEP) Collider. Additionally, the ATLAS
collaboration has reported a corroborative excess in the di-photon final state
within the same mass range, albeit with slightly lower significance. Our
approach involves the superposition of CP-even and CP-odd Higgs bosons within
the Type-III Two-Higgs Doublet Model (2HDM) to simultaneously explain these
excesses at 1$\sigma$ Confidence Level (C.L.), while remaining consistent with
current theoretical and experimental constraints.
|
[
{
"created": "Sun, 5 May 2024 11:33:08 GMT",
"version": "v1"
}
] |
2024-05-07
|
[
[
"Benbrik",
"Rachid",
""
],
[
"Boukidi",
"Mohammed",
""
],
[
"Moretti",
"Stefano",
""
]
] |
We propose an explanation for the observed excesses around 95 GeV in the di-photon and di-tau invariant mass distributions, as reported by the CMS collaboration at the Large Hadron Collider (LHC). These findings are complemented by a long-standing discrepancy in the $b\bar{b}$ invariant mass at the Large Electron-Positron (LEP) Collider. Additionally, the ATLAS collaboration has reported a corroborative excess in the di-photon final state within the same mass range, albeit with slightly lower significance. Our approach involves the superposition of CP-even and CP-odd Higgs bosons within the Type-III Two-Higgs Doublet Model (2HDM) to simultaneously explain these excesses at 1$\sigma$ Confidence Level (C.L.), while remaining consistent with current theoretical and experimental constraints.
|
1407.5053
|
Kei Yagyu
|
Cheng-Wei Chiang, Shinya Kanemura and Kei Yagyu
|
Novel Constraint on Parameter Space of the Georgi-Machacek Model by
Current LHC Data
|
10 pages, 3 figures, references added, Fig. 1 modified
|
Phys. Rev. D 90, 115025 (2014)
|
10.1103/PhysRevD.90.115025
|
UT-HET-096
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The same-sign diboson process $pp\to W^\pm W^\pm jj$ has been measured at the
LHC using leptonic decay channels of the $W$ bosons, with production cross
sections of two fiducial regions reported to be consistent with the standard
model expectations within 1 sigma. These results constrain new physics models
with a modified $W^+W^+W^-W^-$ vertex. We consider in particular the
Georgi-Machacek model in which the quartic $W$ boson vertex is effectively
modified due to mediations of new Higgs bosons in the model. The relevant
gauge-gauge-scalar couplings are all proportional to the vacuum expectation
value of the isospin triplets, which can be of $\mathcal{O}(10)$ GeV because of
custodial vacuum alignment. Using the current 8-TeV data at the LHC, we exclude
parameter space on the plane of the triplet vacuum expectation value and the
new Higgs boson mass. The expected discovery reach at the 14-TeV LHC is also
studied.
|
[
{
"created": "Fri, 18 Jul 2014 16:13:33 GMT",
"version": "v1"
},
{
"created": "Sat, 15 Nov 2014 03:03:48 GMT",
"version": "v2"
}
] |
2015-01-07
|
[
[
"Chiang",
"Cheng-Wei",
""
],
[
"Kanemura",
"Shinya",
""
],
[
"Yagyu",
"Kei",
""
]
] |
The same-sign diboson process $pp\to W^\pm W^\pm jj$ has been measured at the LHC using leptonic decay channels of the $W$ bosons, with production cross sections of two fiducial regions reported to be consistent with the standard model expectations within 1 sigma. These results constrain new physics models with a modified $W^+W^+W^-W^-$ vertex. We consider in particular the Georgi-Machacek model in which the quartic $W$ boson vertex is effectively modified due to mediations of new Higgs bosons in the model. The relevant gauge-gauge-scalar couplings are all proportional to the vacuum expectation value of the isospin triplets, which can be of $\mathcal{O}(10)$ GeV because of custodial vacuum alignment. Using the current 8-TeV data at the LHC, we exclude parameter space on the plane of the triplet vacuum expectation value and the new Higgs boson mass. The expected discovery reach at the 14-TeV LHC is also studied.
|
1605.07040
|
Sergey Afonin
|
S. S. Afonin
|
Lower and upper bounds on the mass of light quark-antiquark scalar
resonance in the SVZ sum rules
|
Matches the published version
|
Int. J. Mod. Phys. A31, 1650164 (2016)
|
10.1142/S0217751X16501645
| null |
hep-ph hep-th nucl-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The calculation of the mass of light scalar isosinglet meson within the
Shifman-Vainshtein-Zakharov (SVZ) sum rules is revisited. We develop simple
analytical methods for estimation of hadron masses in the SVZ approach and try
to reveal the origin of their numerical values. The calculations of hadron
parameters in the SVZ sum rules are known to be heavily based on a choice of
the perturbative threshold. This choice requires some important ad hoc
information. We show analytically that the scalar mass under consideration has
a lower and upper bound which are independent of this choice: $0.78\lesssim
m_s\lesssim1.28$ GeV.
|
[
{
"created": "Mon, 23 May 2016 14:51:28 GMT",
"version": "v1"
},
{
"created": "Thu, 24 Nov 2016 13:28:37 GMT",
"version": "v2"
}
] |
2016-11-28
|
[
[
"Afonin",
"S. S.",
""
]
] |
The calculation of the mass of light scalar isosinglet meson within the Shifman-Vainshtein-Zakharov (SVZ) sum rules is revisited. We develop simple analytical methods for estimation of hadron masses in the SVZ approach and try to reveal the origin of their numerical values. The calculations of hadron parameters in the SVZ sum rules are known to be heavily based on a choice of the perturbative threshold. This choice requires some important ad hoc information. We show analytically that the scalar mass under consideration has a lower and upper bound which are independent of this choice: $0.78\lesssim m_s\lesssim1.28$ GeV.
|
hep-ph/0608318
|
Zsolt Szep
|
T. Herpay and Zs. Szep
|
The boundary of the first order chiral phase transition in the
m_pi-m_K--plane with a linear sigma model
|
4 pages, 1 figure, uses espcrc1.sty; to appear in the proceedings of
Strong and Electroweak Matter 2006 (SEWM06), BNL, May 2006
|
Nucl.Phys.A785:174-177,2007
|
10.1016/j.nuclphysa.2006.11.060
| null |
hep-ph
| null |
Tree-level and complete one-loop parametrisation of the linear sigma model
(LSM) is performed and the phase boundary between first order and crossover
transition regions of the m_pi-m_K-plane is determined using the optimised
perturbation theory (OPT) as a resummation tool of perturbative series. Away
from the physical point the parameters of the model were determined by making
use of chiral perturbation theory (ChPT). The location of the phase boundary
for m_pi=m_K and of the tricritical point (TCP) on the m_pi=0 were estimated.
|
[
{
"created": "Wed, 30 Aug 2006 10:42:35 GMT",
"version": "v1"
}
] |
2008-11-26
|
[
[
"Herpay",
"T.",
""
],
[
"Szep",
"Zs.",
""
]
] |
Tree-level and complete one-loop parametrisation of the linear sigma model (LSM) is performed and the phase boundary between first order and crossover transition regions of the m_pi-m_K-plane is determined using the optimised perturbation theory (OPT) as a resummation tool of perturbative series. Away from the physical point the parameters of the model were determined by making use of chiral perturbation theory (ChPT). The location of the phase boundary for m_pi=m_K and of the tricritical point (TCP) on the m_pi=0 were estimated.
|
hep-ph/9409330
|
Paul Frampton
|
Paul H. Frampton and Thomas W. Kephart
|
Simple Non-Abelian Finite Flavor Groups and Fermion Masses
|
23 pages, IFP-702-UNC and VAND-TH-94-8
|
Int.J.Mod.Phys.A10:4689-4704,1995
|
10.1142/S0217751X95002187
| null |
hep-ph
| null |
The use of nonabelian discrete groups G as family symmetries is discussed in
detail. Out of all such groups up to order g = 31, the most appealing
candidates are two subgroups of SU(2): the dicyclic [double dihedral] group G =
$Q_6 ={ }^{(d)}D_3$ ( g = 12 ) and the double tetrahedral group $^{(d)}T =
Q_4\tilde{\times}Z_3$ ( g = 24 ). Both can allow a hierarchy $t > b, \tau > c >
s, \mu > u, d, e$. The top quark is uniquely allowed to have a G symmetric
mass. Sequential breaking of G and radiative corrections give the smaller
masses. Anomaly freedom for gauging $G \subset SU(2)$ is a strong constraint in
assignment of fermions to representations of G.
|
[
{
"created": "Thu, 15 Sep 1994 17:13:23 GMT",
"version": "v1"
}
] |
2011-01-13
|
[
[
"Frampton",
"Paul H.",
""
],
[
"Kephart",
"Thomas W.",
""
]
] |
The use of nonabelian discrete groups G as family symmetries is discussed in detail. Out of all such groups up to order g = 31, the most appealing candidates are two subgroups of SU(2): the dicyclic [double dihedral] group G = $Q_6 ={ }^{(d)}D_3$ ( g = 12 ) and the double tetrahedral group $^{(d)}T = Q_4\tilde{\times}Z_3$ ( g = 24 ). Both can allow a hierarchy $t > b, \tau > c > s, \mu > u, d, e$. The top quark is uniquely allowed to have a G symmetric mass. Sequential breaking of G and radiative corrections give the smaller masses. Anomaly freedom for gauging $G \subset SU(2)$ is a strong constraint in assignment of fermions to representations of G.
|
2012.14034
|
Harri Waltari
|
Amit Chakraborty, Stefano Moretti, Claire H. Shepherd-Themistocleous
and Harri Waltari
|
Extraction of neutrino Yukawa parameters from displaced vertices of
sneutrinos
|
21 pages, 7 figures. Revised version, matches the version accepted to
JHEP
|
JHEP 06 (2021) 027
|
10.1007/JHEP06(2021)027
| null |
hep-ph
|
http://creativecommons.org/licenses/by/4.0/
|
We study displaced signatures of sneutrino pairs potentially emerging at the
Large Hadron Collider (LHC) in a Next-to-Minimal Supersymmetric Standard Model
supplemented with right-handed neutrinos triggering a Type-I seesaw mechanism.
We show how such signatures can be established through a heavy Higgs portal in
the presence of both leptonic and hadronic decays of the sneutrinos. We finally
illustrate how the Yukawa parameters of the latter can be extracted from
fitting kinematical quantities pertaining to the corresponding two displaced
vertices, thereby characterising the dynamics of the underlying mechanism of
neutrino mass generation. We show our numerical results for the case of both
the current and High-Luminosity LHC.
|
[
{
"created": "Sun, 27 Dec 2020 23:43:33 GMT",
"version": "v1"
},
{
"created": "Fri, 21 May 2021 10:28:50 GMT",
"version": "v2"
}
] |
2021-06-07
|
[
[
"Chakraborty",
"Amit",
""
],
[
"Moretti",
"Stefano",
""
],
[
"Shepherd-Themistocleous",
"Claire H.",
""
],
[
"Waltari",
"Harri",
""
]
] |
We study displaced signatures of sneutrino pairs potentially emerging at the Large Hadron Collider (LHC) in a Next-to-Minimal Supersymmetric Standard Model supplemented with right-handed neutrinos triggering a Type-I seesaw mechanism. We show how such signatures can be established through a heavy Higgs portal in the presence of both leptonic and hadronic decays of the sneutrinos. We finally illustrate how the Yukawa parameters of the latter can be extracted from fitting kinematical quantities pertaining to the corresponding two displaced vertices, thereby characterising the dynamics of the underlying mechanism of neutrino mass generation. We show our numerical results for the case of both the current and High-Luminosity LHC.
|
1012.4377
|
Krishna Kingkar Pathak
|
Bhaskar Jyoti Hazarika, Krishna Kingkar Pathak and D K Choudhury
|
Isgur-Wise function in a QCD potential model with coulombic potential as
perturbation
|
paper has been modified in Airy functions calculation upto o(r^3)
|
Mod. Phys. Lett. A, Vol. 26, No. 21 (2011) 1547-1554
|
10.1142/S0217732311036000
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We study heavy light mesons in a QCD inspired quark model with the Cornell
potential$-\frac{4\alpha_{S}}{3r}+br+c$. Here we consider the linear term $br$
as the parent and $-\frac{4\alpha_{S}}{3r}+c$ i.e.the Coloumbic part as the
perturbation.The linear parent leads to Airy function as the unperturbed
wavefunction. We then use the Dalgarno method of perturbation theory to obtain
the total wavefunction corrected upto first order with Coulombic peice as the
perturbation.With these wavefunctions, we study the Isgur-Wise function and
calculate its slope and curvature.
|
[
{
"created": "Mon, 20 Dec 2010 16:10:55 GMT",
"version": "v1"
},
{
"created": "Mon, 28 Mar 2011 01:22:28 GMT",
"version": "v2"
},
{
"created": "Fri, 26 Aug 2011 15:01:11 GMT",
"version": "v3"
}
] |
2015-05-20
|
[
[
"Hazarika",
"Bhaskar Jyoti",
""
],
[
"Pathak",
"Krishna Kingkar",
""
],
[
"Choudhury",
"D K",
""
]
] |
We study heavy light mesons in a QCD inspired quark model with the Cornell potential$-\frac{4\alpha_{S}}{3r}+br+c$. Here we consider the linear term $br$ as the parent and $-\frac{4\alpha_{S}}{3r}+c$ i.e.the Coloumbic part as the perturbation.The linear parent leads to Airy function as the unperturbed wavefunction. We then use the Dalgarno method of perturbation theory to obtain the total wavefunction corrected upto first order with Coulombic peice as the perturbation.With these wavefunctions, we study the Isgur-Wise function and calculate its slope and curvature.
|
hep-ph/9510266
| null |
Thomas Hambye
|
Symmetry breaking induced by top quark loops from a model without scalar
mass
|
latex
|
Phys.Lett.B371:87-92,1996
|
10.1016/0370-2693(95)01570-1
|
UCL-IPT-95-16
|
hep-ph
| null |
Considering the standard model as an effective electroweak theory, in which
we have no scalar mass term in the Higgs potential $(\mu^2=0)$, we show that
the spontaneous symmetry breaking of $SU(2)_L \times U(1)$ can be induced by
top loops. The Higgs boson mass obtained is smaller than 300 GeV.
|
[
{
"created": "Tue, 10 Oct 1995 11:47:12 GMT",
"version": "v1"
}
] |
2011-01-13
|
[
[
"Hambye",
"Thomas",
""
]
] |
Considering the standard model as an effective electroweak theory, in which we have no scalar mass term in the Higgs potential $(\mu^2=0)$, we show that the spontaneous symmetry breaking of $SU(2)_L \times U(1)$ can be induced by top loops. The Higgs boson mass obtained is smaller than 300 GeV.
|
1212.4856
|
David Morrissey
|
Karol Krizka, Abhishek Kumar, and David E. Morrissey
|
Very Light Scalar Top Quarks at the LHC
|
38 pages, 5 figures, 2 tables, added references and comments to match
journal version
| null |
10.1103/PhysRevD.87.095016
| null |
hep-ph hep-ex
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
A very light scalar top (stop) superpartner is motivated by naturalness and
electroweak baryogenesis. When the mass of the stop is less than the sum of the
masses of the top quark and the lightest neutralino superpartner, as well as
the of the masses of the lightest chargino and the bottom quark, the dominant
decay channels of the stop will be three-body, four-body, or flavour violating.
In this work, we investigate the direct and indirect constraints on a light
stop, we compute the relative decay branching fractions to these channels, and
we study the sensitivity of existing LHC searches to each of them.
|
[
{
"created": "Wed, 19 Dec 2012 21:19:38 GMT",
"version": "v1"
},
{
"created": "Wed, 18 Dec 2013 17:59:52 GMT",
"version": "v2"
}
] |
2013-12-19
|
[
[
"Krizka",
"Karol",
""
],
[
"Kumar",
"Abhishek",
""
],
[
"Morrissey",
"David E.",
""
]
] |
A very light scalar top (stop) superpartner is motivated by naturalness and electroweak baryogenesis. When the mass of the stop is less than the sum of the masses of the top quark and the lightest neutralino superpartner, as well as the of the masses of the lightest chargino and the bottom quark, the dominant decay channels of the stop will be three-body, four-body, or flavour violating. In this work, we investigate the direct and indirect constraints on a light stop, we compute the relative decay branching fractions to these channels, and we study the sensitivity of existing LHC searches to each of them.
|
1208.4513
|
Pablo Roig
|
P. Roig, I. M. Nugent, T. Przedzinski, O. Shekhovtsova, Z. Was
|
Theoretical inputs and errors in the new hadronic currents in TAUOLA
|
5 pages, no figures, contribution to the Proceedings of the
QCD@Work12 Conference
| null |
10.1063/1.4763492
|
UAB-FT-718
|
hep-ph hep-ex
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The new hadronic currents implemented in the TAUOLA library are obtained in
the unified and consistent framework of Resonance Chiral Theory: a Lagrangian
approach in which the resonances exchanged in the hadronic tau decays are
active degrees of freedom included in a way that reproduces the low-energy
results of Chiral Perturbation Theory. The short-distance QCD constraints on
the imaginary part of the spin-one correlators yield relations among the
couplings that render the theory predictive.
In this communication, the obtaining of the two- and three-meson form factors
is sketched. One of the criticisms to our framework is that the error may be as
large as 1/3, since it is a realization of the large-N_C limit of QCD in a
meson theory. A number of arguments are given which disfavor that claim
pointing to smaller errors, which would explain the phenomenological success of
our description in these decays. Finally, other minor sources of error and
current improvements of the code are discussed.
|
[
{
"created": "Wed, 22 Aug 2012 14:43:20 GMT",
"version": "v1"
}
] |
2015-06-11
|
[
[
"Roig",
"P.",
""
],
[
"Nugent",
"I. M.",
""
],
[
"Przedzinski",
"T.",
""
],
[
"Shekhovtsova",
"O.",
""
],
[
"Was",
"Z.",
""
]
] |
The new hadronic currents implemented in the TAUOLA library are obtained in the unified and consistent framework of Resonance Chiral Theory: a Lagrangian approach in which the resonances exchanged in the hadronic tau decays are active degrees of freedom included in a way that reproduces the low-energy results of Chiral Perturbation Theory. The short-distance QCD constraints on the imaginary part of the spin-one correlators yield relations among the couplings that render the theory predictive. In this communication, the obtaining of the two- and three-meson form factors is sketched. One of the criticisms to our framework is that the error may be as large as 1/3, since it is a realization of the large-N_C limit of QCD in a meson theory. A number of arguments are given which disfavor that claim pointing to smaller errors, which would explain the phenomenological success of our description in these decays. Finally, other minor sources of error and current improvements of the code are discussed.
|
hep-ph/9512284
|
Thomas Gehrmann
|
T. Gehrmann
|
Production of $J/\psi$-pairs at HERA-$\vec{{\rm N}}$
|
8 pages, LATeX, 3 figures availabe as .uu-file
|
Phys.Rev. D53 (1996) 5310-5313
|
10.1103/PhysRevD.53.5310
|
DTP/95/80
|
hep-ph
| null |
The production of $J/\psi$-pairs as a possible measure of the polarized gluon
distribution $\Delta G(x)$ is studied for proton--nucleon collisions at
$\sqrt{s} =40\;\mbox{GeV}^2$ (HERA-$\vec{{\rm N}}$). Possibilities of
reconstructing the helicity state of at least one of the $J/\psi$'s are
critically reviewed. The observation of production asymmetries in the single
polarized mode of HERA-$\vec{{\rm N}}$ is found to be not feasible.
|
[
{
"created": "Tue, 12 Dec 1995 11:36:42 GMT",
"version": "v1"
}
] |
2009-10-28
|
[
[
"Gehrmann",
"T.",
""
]
] |
The production of $J/\psi$-pairs as a possible measure of the polarized gluon distribution $\Delta G(x)$ is studied for proton--nucleon collisions at $\sqrt{s} =40\;\mbox{GeV}^2$ (HERA-$\vec{{\rm N}}$). Possibilities of reconstructing the helicity state of at least one of the $J/\psi$'s are critically reviewed. The observation of production asymmetries in the single polarized mode of HERA-$\vec{{\rm N}}$ is found to be not feasible.
|
0810.3863
|
Michal Malinsky
|
Stefan Antusch, Stephen F. King, Michal Malinsky
|
Perturbative Estimates of Lepton Mixing Angles in Unified Models
|
21 pages; v2: minor corrections
|
Nucl.Phys.B820:32-46,2009
|
10.1016/j.nuclphysb.2009.05.006
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Many unified models predict two large neutrino mixing angles, with the
charged lepton mixing angles being small and quark-like, and the neutrino
masses being hierarchical. Assuming this, we present simple approximate
analytic formulae giving the lepton mixing angles in terms of the underlying
high energy neutrino mixing angles together with small perturbations due to
both charged lepton corrections and renormalisation group (RG) effects,
including also the effects of third family canonical normalization (CN). We
apply the perturbative formulae to the ubiquitous case of tri-bimaximal
neutrino mixing at the unification scale, in order to predict the theoretical
corrections to mixing angle predictions and sum rule relations, and give a
general discussion of all limiting cases.
|
[
{
"created": "Tue, 21 Oct 2008 15:53:28 GMT",
"version": "v1"
},
{
"created": "Thu, 6 Nov 2008 16:11:39 GMT",
"version": "v2"
}
] |
2010-04-15
|
[
[
"Antusch",
"Stefan",
""
],
[
"King",
"Stephen F.",
""
],
[
"Malinsky",
"Michal",
""
]
] |
Many unified models predict two large neutrino mixing angles, with the charged lepton mixing angles being small and quark-like, and the neutrino masses being hierarchical. Assuming this, we present simple approximate analytic formulae giving the lepton mixing angles in terms of the underlying high energy neutrino mixing angles together with small perturbations due to both charged lepton corrections and renormalisation group (RG) effects, including also the effects of third family canonical normalization (CN). We apply the perturbative formulae to the ubiquitous case of tri-bimaximal neutrino mixing at the unification scale, in order to predict the theoretical corrections to mixing angle predictions and sum rule relations, and give a general discussion of all limiting cases.
|
1912.12494
|
Alexander Studenikin
|
Alexander Studenikin
|
Neutrino oscillations and evolution in external environments: New
effects
|
6 pages in LaTex, to appear in the proceedings of the European
Physical Society Conference on High Energy Physics - EPS-HEP2019 - 10-17
July, 2019, Ghent, Belgium. arXiv admin note: text overlap with
arXiv:1912.12491
|
Pos EPS-HEP2019 374
| null | null |
hep-ph astro-ph.HE
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
During a period of about two decades we have realized a programme of
systematic investigations of different aspects of neutrino propagation in
extreme external environments and have predicted and studied several new
phenomena that are engendered by the presence of external magnetic fields and
dense matter. The starting point that underlies the research is the fact that
the electromagnetic properties of neutrinos open a window to new physics
\cite{Giunti:2014ixa,Studenikin:2008bd, Studenikin:2018vnp}. In these brief
notes, we recall several new phenomena that have been proposed and investigated
earlier. In particular, we discuss: 1) the spin light of neutrino in matter, 2)
the neutrino energy quantization in rotating matter, and 3) neutrino start
turning mechanism. Then we dwell on results of recent studies: 4) the effects
of interplay of neutrino flavour and spin oscillations in a magnetic field, 5)
the quantum theory of neutrino spin and spin-flavour oscillations engendered by
the transversal mater currents, 6) the amplitude modulation of the flavour
neutrino oscillation probability by the transversal matter current. As for
references to the literature, only those papers are included in which a
particular effect was proposed and considered for the first time and in a
number of cases references are also be given to the most recent articles, which
contain detailed references to the available literature on the issue.
|
[
{
"created": "Sat, 28 Dec 2019 18:05:52 GMT",
"version": "v1"
}
] |
2020-09-04
|
[
[
"Studenikin",
"Alexander",
""
]
] |
During a period of about two decades we have realized a programme of systematic investigations of different aspects of neutrino propagation in extreme external environments and have predicted and studied several new phenomena that are engendered by the presence of external magnetic fields and dense matter. The starting point that underlies the research is the fact that the electromagnetic properties of neutrinos open a window to new physics \cite{Giunti:2014ixa,Studenikin:2008bd, Studenikin:2018vnp}. In these brief notes, we recall several new phenomena that have been proposed and investigated earlier. In particular, we discuss: 1) the spin light of neutrino in matter, 2) the neutrino energy quantization in rotating matter, and 3) neutrino start turning mechanism. Then we dwell on results of recent studies: 4) the effects of interplay of neutrino flavour and spin oscillations in a magnetic field, 5) the quantum theory of neutrino spin and spin-flavour oscillations engendered by the transversal mater currents, 6) the amplitude modulation of the flavour neutrino oscillation probability by the transversal matter current. As for references to the literature, only those papers are included in which a particular effect was proposed and considered for the first time and in a number of cases references are also be given to the most recent articles, which contain detailed references to the available literature on the issue.
|
1507.04431
|
Takaaki Nomura
|
Chuan-Hung Chen, Takaaki Nomura
|
2 TeV Higgs boson and diboson excess at the LHC
|
12 pages, 7 figures, title changed, Fig.2 corrected, comments and
references added, version to appear in PLB
| null |
10.1016/j.physletb.2015.08.028
| null |
hep-ph hep-ex
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Diboson resonance with mass around 2 TeV in the dijet invariant mass spectrum
is reported by ATLAS experiment in proton-proton collisions at $\sqrt{s}=8$
TeV. We propose that the candidate of resonance is a heavy neutral Higgs $H^0$
or charged Higgs $H^\pm$ and use the extended two-Higgs-doublet (THD) to
demonstrate the potentiality. We find that the large Yukawa coupling to the
first generation of quarks can be realized in THD and the required value for
producing the right resonance production cross section is of ${\cal
O}(0.06-0.2)$. Besides $WW/ZZ$ channels, we find that if the mass of
pseudoscalar $A^0$ satisfies the jet mass tagging condition $|m_j - m_{Z/W}|<
13$ GeV, the diboson excess could be also caused by $ZA^0$ or $WA^0$ channel.
|
[
{
"created": "Thu, 16 Jul 2015 01:55:06 GMT",
"version": "v1"
},
{
"created": "Mon, 20 Jul 2015 13:56:18 GMT",
"version": "v2"
},
{
"created": "Tue, 18 Aug 2015 12:17:32 GMT",
"version": "v3"
}
] |
2015-09-30
|
[
[
"Chen",
"Chuan-Hung",
""
],
[
"Nomura",
"Takaaki",
""
]
] |
Diboson resonance with mass around 2 TeV in the dijet invariant mass spectrum is reported by ATLAS experiment in proton-proton collisions at $\sqrt{s}=8$ TeV. We propose that the candidate of resonance is a heavy neutral Higgs $H^0$ or charged Higgs $H^\pm$ and use the extended two-Higgs-doublet (THD) to demonstrate the potentiality. We find that the large Yukawa coupling to the first generation of quarks can be realized in THD and the required value for producing the right resonance production cross section is of ${\cal O}(0.06-0.2)$. Besides $WW/ZZ$ channels, we find that if the mass of pseudoscalar $A^0$ satisfies the jet mass tagging condition $|m_j - m_{Z/W}|< 13$ GeV, the diboson excess could be also caused by $ZA^0$ or $WA^0$ channel.
|
1305.2172
|
A. D. Polosa
|
L Maiani, AD Polosa, V Riquer
|
Bounds to the Higgs Sector Masses in Minimal Supersymmetry from LHC Data
|
5 pages, 5 figures, comments added, references updated
|
Physics Letters B 724 (2013) 274-277
|
10.1016/j.physletb.2013.06.026
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We update our analysis of the Higgs sector masses in Minimal Supersymmetry
and in the Two-Higgs Doublet Model to the final ATLAS and CMS data from the
2011-2012 LHC run.
|
[
{
"created": "Thu, 9 May 2013 18:35:37 GMT",
"version": "v1"
},
{
"created": "Sun, 16 Jun 2013 08:05:04 GMT",
"version": "v2"
}
] |
2013-07-11
|
[
[
"Maiani",
"L",
""
],
[
"Polosa",
"AD",
""
],
[
"Riquer",
"V",
""
]
] |
We update our analysis of the Higgs sector masses in Minimal Supersymmetry and in the Two-Higgs Doublet Model to the final ATLAS and CMS data from the 2011-2012 LHC run.
|
hep-ph/0006324
|
V. A. Ilyin
|
V.A. Ilyin, M. Maltoni, V.A. Novikov, L.B. Okun, A.N. Rozanov and M.I.
Vysotsky
|
On the search for 50 GeV neutrinos
|
Standard LaTeX, 9 pages, 2 tables, 3 figures
|
Phys.Lett. B503 (2001) 126-132
|
10.1016/S0370-2693(01)00243-X
|
ITEP-PH-2/2000, IFIC-00/39, SINP MSU 2000-20/624
|
hep-ph
| null |
Using the computer code CompHEP we estimate the number of events and the
background, at LEP II and TESLA, for the reaction $e^+ e^- \to N\bar{N}\gamma$,
where $N$ is a hypothetical Dirac neutrino with mass of the order of 50 GeV.
|
[
{
"created": "Wed, 28 Jun 2000 17:28:40 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Ilyin",
"V. A.",
""
],
[
"Maltoni",
"M.",
""
],
[
"Novikov",
"V. A.",
""
],
[
"Okun",
"L. B.",
""
],
[
"Rozanov",
"A. N.",
""
],
[
"Vysotsky",
"M. I.",
""
]
] |
Using the computer code CompHEP we estimate the number of events and the background, at LEP II and TESLA, for the reaction $e^+ e^- \to N\bar{N}\gamma$, where $N$ is a hypothetical Dirac neutrino with mass of the order of 50 GeV.
|
hep-ph/9310237
|
Pankaj Jain
|
Pankaj Jain and John P. Ralston
|
Three Successful Tests of Color Transparency and Nuclear Filtering
|
(To be published in the Proceedings of the V Rencontre de Blois
meeting on Elastic and Diffractive Phenomenon, edited C. I. Tan and H. M.
Fried (Brown University 1993) (World Scientific, in press)), 6 pages, 1
figure (hard copy available upon request), report # KUHEP-93-47
| null | null | null |
hep-ph
| null |
We review the theoretical formalism for hard exclusive processes in a nuclear
medium. Theory suggests that these processes will show the very interesting
phenomena of color transparency and nuclear filtering. The survival probability
in nuclear media has also been predicted to show a scaling behavior at large
momentum and large nuclear number. We show that all of these effects may have
already been seen experimentally.
|
[
{
"created": "Wed, 6 Oct 1993 16:51:24 GMT",
"version": "v1"
}
] |
2009-09-25
|
[
[
"Jain",
"Pankaj",
""
],
[
"Ralston",
"John P.",
""
]
] |
We review the theoretical formalism for hard exclusive processes in a nuclear medium. Theory suggests that these processes will show the very interesting phenomena of color transparency and nuclear filtering. The survival probability in nuclear media has also been predicted to show a scaling behavior at large momentum and large nuclear number. We show that all of these effects may have already been seen experimentally.
|
hep-ph/0008107
|
Gursevil Turan
|
E.O.Iltan (METU, Ankara) and G.Turan (METU, Ankara)
|
b --> s \tau^+ \tau^- decay in the two Higgs doublet model with flavor
changing neutral currents
|
16 pages, 15 figures
|
Phys.Rev. D63 (2001) 115007
|
10.1103/PhysRevD.63.115007
| null |
hep-ph
| null |
We study the decay width and forward-backward asymmetry of the lepton pair
for the inclusive decay b --> s \tau^+ \tau^- in the two Higgs doublet model
with three level flavor changing neutral currents (model III) and analyse the
dependencies of these quantities on the model III parameters, including the
leading order QCD corrections. We found that there is a considerable
enhancement in the decay width and neutral Higgs effects are detectable for
large values of the parameter \bar{\xi}_{N,\tau\tau}^D.
|
[
{
"created": "Fri, 11 Aug 2000 08:33:22 GMT",
"version": "v1"
},
{
"created": "Wed, 2 May 2001 12:04:33 GMT",
"version": "v2"
}
] |
2009-10-31
|
[
[
"Iltan",
"E. O.",
"",
"METU, Ankara"
],
[
"Turan",
"G.",
"",
"METU, Ankara"
]
] |
We study the decay width and forward-backward asymmetry of the lepton pair for the inclusive decay b --> s \tau^+ \tau^- in the two Higgs doublet model with three level flavor changing neutral currents (model III) and analyse the dependencies of these quantities on the model III parameters, including the leading order QCD corrections. We found that there is a considerable enhancement in the decay width and neutral Higgs effects are detectable for large values of the parameter \bar{\xi}_{N,\tau\tau}^D.
|
hep-ph/0201008
|
Danny Marfatia
|
Paul H. Frampton, Sheldon L. Glashow and Danny Marfatia
|
Zeroes of the Neutrino Mass Matrix
|
Version to appear in PLB
|
Phys.Lett. B536 (2002) 79-82
|
10.1016/S0370-2693(02)01817-8
|
IFP-805-UNC
|
hep-ph
| null |
We assume there to be precisely three left-handed neutrino states whose
Majorana masses are generated by an unspecified mechanism. Were CP conserved,
the symmetric neutrino mass matrix M would be real and all six of its distinct
entries could be experimentally determined. But CP is not conserved so that M
is likely to be complex. As a result, not all nine of its
convention-independent real parameters can be determined without an appeal to
theory. Thus we examine the possibility that a restricted class of neutrino
mass matrices may suffice to describe current data, namely those complex
symmetric matrices several of whose entries vanish. We find that there are
seven acceptable textures with two independent zeroes, and we explore their
contrasting phenomenological implications. Textures with more than two
independent zeroes appear to be excluded by experiment.
|
[
{
"created": "Wed, 2 Jan 2002 21:00:06 GMT",
"version": "v1"
},
{
"created": "Fri, 26 Apr 2002 20:15:27 GMT",
"version": "v2"
}
] |
2009-11-07
|
[
[
"Frampton",
"Paul H.",
""
],
[
"Glashow",
"Sheldon L.",
""
],
[
"Marfatia",
"Danny",
""
]
] |
We assume there to be precisely three left-handed neutrino states whose Majorana masses are generated by an unspecified mechanism. Were CP conserved, the symmetric neutrino mass matrix M would be real and all six of its distinct entries could be experimentally determined. But CP is not conserved so that M is likely to be complex. As a result, not all nine of its convention-independent real parameters can be determined without an appeal to theory. Thus we examine the possibility that a restricted class of neutrino mass matrices may suffice to describe current data, namely those complex symmetric matrices several of whose entries vanish. We find that there are seven acceptable textures with two independent zeroes, and we explore their contrasting phenomenological implications. Textures with more than two independent zeroes appear to be excluded by experiment.
|
hep-ph/0608087
|
Jong-Phil Lee
|
Jong-Phil Lee (KIAS)
|
Radiative $B\to K_1$ decays in the light-cone sum rules
|
15 pages, 4 figures
|
Phys.Rev.D74:074001,2006
|
10.1103/PhysRevD.74.074001
| null |
hep-ph
| null |
The weak form factor for $B\to K_{1B}$ where $K_{1B}$ is the $^1P_1$ state is
calculated in the light-cone sum rules (LCSR). Combining the quark model result
for the form factor of $B\to K_{1A}$ with $K_{1A}$ being the $^3P_1$ state, we
have larger values for $B\to K_1$ form factors than the previous LCSR results.
The increased form factors reduce the discrepancy between theory and the
experimental data for $B\to K_1 \gamma$. Some phenomenological meanings are
also discussed.
|
[
{
"created": "Tue, 8 Aug 2006 08:22:50 GMT",
"version": "v1"
}
] |
2008-11-26
|
[
[
"Lee",
"Jong-Phil",
"",
"KIAS"
]
] |
The weak form factor for $B\to K_{1B}$ where $K_{1B}$ is the $^1P_1$ state is calculated in the light-cone sum rules (LCSR). Combining the quark model result for the form factor of $B\to K_{1A}$ with $K_{1A}$ being the $^3P_1$ state, we have larger values for $B\to K_1$ form factors than the previous LCSR results. The increased form factors reduce the discrepancy between theory and the experimental data for $B\to K_1 \gamma$. Some phenomenological meanings are also discussed.
|
1504.07196
|
P. S. Bhupal Dev
|
P. S. Bhupal Dev and Rabindra N. Mohapatra
|
A TeV Scale Model for Baryon and Lepton Number Violation and Resonant
Baryogenesis
|
7 pages, 6 figures; some typos fixed and references added
|
Phys. Rev. D 92, 016007 (2015)
|
10.1103/PhysRevD.92.016007
|
MAN/HEP/2015/07, UMD-PP-015-008
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
A simple TeV scale model for baryon and lepton number violation is presented,
where neutrino mass arises via a one-loop radiative seesaw effect and
B-violation obeys $\Delta B=2$ selection rule. The stability of proton is
connected to the neutrino mass generation. Matter-antimatter asymmetry is
generated in this model via resonant baryogenesis mechanism.
|
[
{
"created": "Mon, 27 Apr 2015 18:24:25 GMT",
"version": "v1"
},
{
"created": "Fri, 5 Jun 2015 18:13:49 GMT",
"version": "v2"
}
] |
2015-07-29
|
[
[
"Dev",
"P. S. Bhupal",
""
],
[
"Mohapatra",
"Rabindra N.",
""
]
] |
A simple TeV scale model for baryon and lepton number violation is presented, where neutrino mass arises via a one-loop radiative seesaw effect and B-violation obeys $\Delta B=2$ selection rule. The stability of proton is connected to the neutrino mass generation. Matter-antimatter asymmetry is generated in this model via resonant baryogenesis mechanism.
|
hep-ph/0001003
| null |
I.I. Bigi
|
The Lifetimes of Heavy Flavour Hadrons - a Case Study in Quark-Hadron
Duality
|
12 pages, LATEX, no figures, 2 tables; slightly extended version of
Invited Talk given at the 3rd International Conference on B Physics and CP
Violation, Taipeh, Taiwan, Dec. 3 - 7, 1999
| null |
10.1142/9789812791870_0027
|
UND-HEP-99-BIG 07
|
hep-ph
| null |
The status of heavy quark expansions for charm and beauty lifetime ratios is
reviewed. Taking note of the surprising semiquantitative success of this
description for charm hadrons I interprete the new data on $\tau (D_s)$ and
re-iterate the call for more precise measurements of $\tau (\Xi_c^{0,+})$ and
$\tau (\Omega_c)$. A slightly larger $B^-$ than $B_d$ lifetime is starting to
emerge as predicted; the largest lifetime difference in the beauty sector,
namely in $\tau (B_c)$ vs. $\tau (B)$ has correctly been predicted; the problem
posed by the short $\Lambda_b$ lifetime remains. The need for more accurate
data also on $\tau (B_s)$ and $\tau (\Xi_b^{-,0})$ is emphasized. I discuss
quark-hadron duality as the central theoretical issue at stake here.
|
[
{
"created": "Sat, 1 Jan 2000 21:42:56 GMT",
"version": "v1"
}
] |
2016-11-23
|
[
[
"Bigi",
"I. I.",
""
]
] |
The status of heavy quark expansions for charm and beauty lifetime ratios is reviewed. Taking note of the surprising semiquantitative success of this description for charm hadrons I interprete the new data on $\tau (D_s)$ and re-iterate the call for more precise measurements of $\tau (\Xi_c^{0,+})$ and $\tau (\Omega_c)$. A slightly larger $B^-$ than $B_d$ lifetime is starting to emerge as predicted; the largest lifetime difference in the beauty sector, namely in $\tau (B_c)$ vs. $\tau (B)$ has correctly been predicted; the problem posed by the short $\Lambda_b$ lifetime remains. The need for more accurate data also on $\tau (B_s)$ and $\tau (\Xi_b^{-,0})$ is emphasized. I discuss quark-hadron duality as the central theoretical issue at stake here.
|
hep-ph/0007208
|
Pallante
|
Elisabetta Pallante, Antonio Pich
|
Final State Interactions in Kaon Decays
|
30 pages, 1 eps figure
|
Nucl.Phys.B592:294-320,2001
|
10.1016/S0550-3213(00)00601-5
|
FTUV/00-0717, IFIC/00-30
|
hep-ph hep-lat
| null |
We quantify the important effect of strong final state interactions in the
weak $K\to 2\pi$ amplitudes, using the measured $\pi$-$\pi$ phase shifts with
J=0 and $I=0,2$. The main results of this analysis, with their implications for
$\epsilon'/\epsilon$ and the $\Delta I =1/2$ rule, have been already presented
in a previous paper [1]. Here we provide a detailed formal derivation of those
results and further discuss the Standard Model prediction of
$\epsilon'/\epsilon$.
|
[
{
"created": "Wed, 19 Jul 2000 15:02:53 GMT",
"version": "v1"
}
] |
2014-11-17
|
[
[
"Pallante",
"Elisabetta",
""
],
[
"Pich",
"Antonio",
""
]
] |
We quantify the important effect of strong final state interactions in the weak $K\to 2\pi$ amplitudes, using the measured $\pi$-$\pi$ phase shifts with J=0 and $I=0,2$. The main results of this analysis, with their implications for $\epsilon'/\epsilon$ and the $\Delta I =1/2$ rule, have been already presented in a previous paper [1]. Here we provide a detailed formal derivation of those results and further discuss the Standard Model prediction of $\epsilon'/\epsilon$.
|
hep-ph/0009030
|
R. D. Peccei
|
R. D. Peccei
|
Light Scalars in Cosmology
|
10 pages. To appear in the Proceedings of Dark Matter 2000, Santa
Monica, California, February 2000
| null | null | null |
hep-ph
| null |
I discuss here some of the constraints imposed by quantum and gravitational
corrections on two hypothetical excitations, axions and quintessence, which
have important cosmological implications. Although these corrections can be
kept under control, the resulting constraints are not too natural. In
particular, to keep the quintessence field light one must essentially decouple
it from ordinary matter. Some possible suggestions of how to avoid these
troubles are briefly touched upon.
|
[
{
"created": "Mon, 4 Sep 2000 20:49:17 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Peccei",
"R. D.",
""
]
] |
I discuss here some of the constraints imposed by quantum and gravitational corrections on two hypothetical excitations, axions and quintessence, which have important cosmological implications. Although these corrections can be kept under control, the resulting constraints are not too natural. In particular, to keep the quintessence field light one must essentially decouple it from ordinary matter. Some possible suggestions of how to avoid these troubles are briefly touched upon.
|
hep-ph/9701390
|
Timo van Ritbergen
|
T. van Ritbergen, J.A.M. Vermaseren, S.A. Larin
|
The four-loop beta-function in Quantum Chromodynamics
|
9 pages, Latex, 1 figure, uses axodraw.sty
|
Phys.Lett.B400:379-384,1997
|
10.1016/S0370-2693(97)00370-5
|
UM-TH-97-01, NIKHEF-97-001
|
hep-ph
| null |
We present the analytical calculation of the four-loop QCD beta-function
within the minimal subtraction scheme.
|
[
{
"created": "Mon, 27 Jan 1997 19:39:05 GMT",
"version": "v1"
}
] |
2008-11-26
|
[
[
"van Ritbergen",
"T.",
""
],
[
"Vermaseren",
"J. A. M.",
""
],
[
"Larin",
"S. A.",
""
]
] |
We present the analytical calculation of the four-loop QCD beta-function within the minimal subtraction scheme.
|
1011.3341
|
Ulrich Langenfeld
|
Ulrich Langenfeld
|
Threshold Improved QCD Corrections for Stop-Antistop production at
Hadron colliders
|
19 pages, 6 figures
|
JHEP 1107:052,2011
|
10.1007/JHEP07(2011)052
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
I present improved predictions for the total hadronic cross section of
stop-antistop production at hadron colliders including
next-to-next-to-leading-order threshold corrections and approximated Coulomb
corrections. The results are based on soft corrections, which are
logarithmically enhanced near threshold. I present analytic formulas for the
NNLO scaling functions at threshold and explicit numbers for the total hadronic
cross sections for the Tevatron and the LHC. Finally I discuss the systematic
error, the scale uncertainty and the PDF error of the hadronic cross section.
|
[
{
"created": "Mon, 15 Nov 2010 11:04:04 GMT",
"version": "v1"
},
{
"created": "Fri, 8 Jul 2011 09:37:04 GMT",
"version": "v2"
},
{
"created": "Mon, 11 Jul 2011 07:54:53 GMT",
"version": "v3"
}
] |
2011-07-15
|
[
[
"Langenfeld",
"Ulrich",
""
]
] |
I present improved predictions for the total hadronic cross section of stop-antistop production at hadron colliders including next-to-next-to-leading-order threshold corrections and approximated Coulomb corrections. The results are based on soft corrections, which are logarithmically enhanced near threshold. I present analytic formulas for the NNLO scaling functions at threshold and explicit numbers for the total hadronic cross sections for the Tevatron and the LHC. Finally I discuss the systematic error, the scale uncertainty and the PDF error of the hadronic cross section.
|
0812.4267
|
Christian Gross
|
Christian Gross, Arthur Hebecker
|
A Realistic Unified Gauge Coupling from the Micro-Landscape of Orbifold
GUTs
|
v3: 27 pages; added comments
|
Nucl.Phys.B821:354-379,2009
|
10.1016/j.nuclphysb.2009.06.030
|
HD-THEP-08-32
|
hep-ph hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We consider 5-dimensional supersymmetric field theories where supersymmetry
is broken by the Scherk-Schwarz mechanism (or, equivalently, by the F-term VEV
of the radion). In such models, the radion effective potential is calculable in
terms of the 5d gauge coupling, the UV cutoff of the 5d field theory, and the
field content. We provide simple, explicit formulae for the leading part of the
two-loop effective potential. Our analysis applies in particular to 5d orbifold
GUTs motivated by heterotic orbifold models. We focus on potentially realistic
models of this type and make the additional assumption that the UV cutoff scale
is identical with the strong-coupling scale of the 5d gauge theory. Given our
stabilization mechanism, the 5d radius is now fixed in terms of the 5d gauge
coupling and the field content of the model. This implies a prediction for the
effective 4d gauge coupling only in terms of the field content of the model.
Given the `micro-landscape' provided by the different possible distributions of
Standard Model fields between bulk and branes, we find a subset of models with
a realistic unified gauge coupling. We also discuss two possibilities for the
`uplifting' of our SUSY-breaking AdS vacua: One is based on the possible
presence of a weak warping, the other appeals to F-terms in an extra
brane-localized SUSY-breaking sector.
|
[
{
"created": "Mon, 22 Dec 2008 18:57:55 GMT",
"version": "v1"
},
{
"created": "Wed, 20 May 2009 21:33:31 GMT",
"version": "v2"
},
{
"created": "Fri, 14 Aug 2009 17:19:19 GMT",
"version": "v3"
}
] |
2010-04-15
|
[
[
"Gross",
"Christian",
""
],
[
"Hebecker",
"Arthur",
""
]
] |
We consider 5-dimensional supersymmetric field theories where supersymmetry is broken by the Scherk-Schwarz mechanism (or, equivalently, by the F-term VEV of the radion). In such models, the radion effective potential is calculable in terms of the 5d gauge coupling, the UV cutoff of the 5d field theory, and the field content. We provide simple, explicit formulae for the leading part of the two-loop effective potential. Our analysis applies in particular to 5d orbifold GUTs motivated by heterotic orbifold models. We focus on potentially realistic models of this type and make the additional assumption that the UV cutoff scale is identical with the strong-coupling scale of the 5d gauge theory. Given our stabilization mechanism, the 5d radius is now fixed in terms of the 5d gauge coupling and the field content of the model. This implies a prediction for the effective 4d gauge coupling only in terms of the field content of the model. Given the `micro-landscape' provided by the different possible distributions of Standard Model fields between bulk and branes, we find a subset of models with a realistic unified gauge coupling. We also discuss two possibilities for the `uplifting' of our SUSY-breaking AdS vacua: One is based on the possible presence of a weak warping, the other appeals to F-terms in an extra brane-localized SUSY-breaking sector.
|
hep-ph/0512120
|
Antoni Szczurek
|
M. Luszczak and A. Szczurek
|
Gluon transverse momenta and charm quark-antiquark pair production in
$p-\bar p$ collisions at Tevatron
|
30 pages, 16 figures
|
Phys.Rev.D73:054028,2006
|
10.1103/PhysRevD.73.054028
| null |
hep-ph
| null |
We discuss and compare different approaches to include gluon transverse
momenta for heavy quark-antiquark pair production. The correlations in
azimuthal angle and in heavy quark, heavy antiquark transverse momenta are
studied in detail. The results are illustrated with the help of different
unintegrated gluon distribution functons (UGDF) from the literature. We compare
results obtained with on-shell and off-shell matrix elements and kinematics and
quantify where these effects are negligible and where they are essential. We
concentrate on the region of asymmetric transverse momenta of charm quark and
charm antiquark. Most of UGDFs lead in this corner of the phase space to almost
full decorellation in azimuthal angle. We propose correlation observables to be
best suited in order to test the existing models of UGDFs.
|
[
{
"created": "Fri, 9 Dec 2005 10:46:34 GMT",
"version": "v1"
}
] |
2011-07-19
|
[
[
"Luszczak",
"M.",
""
],
[
"Szczurek",
"A.",
""
]
] |
We discuss and compare different approaches to include gluon transverse momenta for heavy quark-antiquark pair production. The correlations in azimuthal angle and in heavy quark, heavy antiquark transverse momenta are studied in detail. The results are illustrated with the help of different unintegrated gluon distribution functons (UGDF) from the literature. We compare results obtained with on-shell and off-shell matrix elements and kinematics and quantify where these effects are negligible and where they are essential. We concentrate on the region of asymmetric transverse momenta of charm quark and charm antiquark. Most of UGDFs lead in this corner of the phase space to almost full decorellation in azimuthal angle. We propose correlation observables to be best suited in order to test the existing models of UGDFs.
|
1205.3036
|
Alberto Reis
|
I. Bediaga, I. I. Bigi, A. Gomes, J. Miranda, J. Otalora, A. C. dos
Reis and A. Veiga
|
Second Generation of 'Miranda Procedure' for CP Violation in Dalitz
Studies of B (\& D \& \tau) Decays
|
29 pages, 7 figures
| null |
10.1103/PhysRevD.86.036005
| null |
hep-ph hep-ex
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The `Miranda Procedure' proposed for analyzing Dalitz plots for CP
asymmetries in charged B and D decays in a model-independent manner is extended
and refined. The complexity of CKM CP phenomenology through order $\lambda^6$
is needed in searches for New Dynamics (ND). Detailed analyses of three-body
final states other great advantages: (i) They give us more powerful tools for
deciding whether an observed CP asymmetry rep- resents the manifestation of ND
and its features. (ii) Many advantages can already be obtained by the `Miranda
Procedure' without construction of a detailed Dalitz plot de- scription. (iii)
One studies CP asymmetries independent of production asymmetries. We illustrate
the power of a second generation Miranda Procedure with examples with time
integrated rates for $B_d/\bar B_d$ decays to final states $K_S\pi+\pi-$ as
trial runs with comments on $B^{\pm} \to K^{\pm}\pi^+\pi^-/K^{\pm}K^+K^-$.
|
[
{
"created": "Mon, 14 May 2012 14:14:31 GMT",
"version": "v1"
}
] |
2013-05-30
|
[
[
"Bediaga",
"I.",
""
],
[
"Bigi",
"I. I.",
""
],
[
"Gomes",
"A.",
""
],
[
"Miranda",
"J.",
""
],
[
"Otalora",
"J.",
""
],
[
"Reis",
"A. C. dos",
""
],
[
"Veiga",
"A.",
""
]
] |
The `Miranda Procedure' proposed for analyzing Dalitz plots for CP asymmetries in charged B and D decays in a model-independent manner is extended and refined. The complexity of CKM CP phenomenology through order $\lambda^6$ is needed in searches for New Dynamics (ND). Detailed analyses of three-body final states other great advantages: (i) They give us more powerful tools for deciding whether an observed CP asymmetry rep- resents the manifestation of ND and its features. (ii) Many advantages can already be obtained by the `Miranda Procedure' without construction of a detailed Dalitz plot de- scription. (iii) One studies CP asymmetries independent of production asymmetries. We illustrate the power of a second generation Miranda Procedure with examples with time integrated rates for $B_d/\bar B_d$ decays to final states $K_S\pi+\pi-$ as trial runs with comments on $B^{\pm} \to K^{\pm}\pi^+\pi^-/K^{\pm}K^+K^-$.
|
hep-ph/9911456
| null |
B. Magradze (A. Razmadze Mathematical Institute, Tbilisi Georgia)
|
Analytic Approach to Perturbative QCD
|
Latex-file, 19 pages, 2 tables, 51 references, to be published in
Int. J. Mod. Phys.A
|
Int.J.Mod.Phys. A15 (2000) 2715-2734
|
10.1142/S0217751X00001117
|
RMI-99-06
|
hep-ph hep-th
| null |
The two-loop invariant (running) coupling of QCD is written in terms of the
Lambert W function. The analyticity structure of the coupling in the complex
Q^2-plane is established. The corresponding analytic coupling is reconstructed
via a dispersion relation. We also consider some other approximations to the
QCD beta-function, when the corresponding couplings are solved in terms of the
Lambert function. The Landau gauge gluon propagator has been considered in the
renormalization group invariant analytic approach (IAA). It is shown that there
is a nonperturbative ambiguity in determination of the anomalous dimension
function of the gluon field. Several analytic solutions for the propagator at
the one-loop order are constructed. Properties of the obtained analytical
solutions are discussed.
|
[
{
"created": "Tue, 23 Nov 1999 20:41:23 GMT",
"version": "v1"
}
] |
2016-12-28
|
[
[
"Magradze",
"B.",
"",
"A. Razmadze Mathematical Institute, Tbilisi Georgia"
]
] |
The two-loop invariant (running) coupling of QCD is written in terms of the Lambert W function. The analyticity structure of the coupling in the complex Q^2-plane is established. The corresponding analytic coupling is reconstructed via a dispersion relation. We also consider some other approximations to the QCD beta-function, when the corresponding couplings are solved in terms of the Lambert function. The Landau gauge gluon propagator has been considered in the renormalization group invariant analytic approach (IAA). It is shown that there is a nonperturbative ambiguity in determination of the anomalous dimension function of the gluon field. Several analytic solutions for the propagator at the one-loop order are constructed. Properties of the obtained analytical solutions are discussed.
|
hep-ph/9805396
|
Hannes Jung
|
H. Jung (Lund), L. Joensson (Lund), H. Kuester (Lund)
|
Resolved photon processes in DIS and small x dynamics
|
15 pages (Latex), 6 figures (Postscript), replaced version because of
wrong references
| null | null |
DESY 98-051, LUNFD6/(NFFL-7156) 1998
|
hep-ph
| null |
It has been found that recent results on forward jet production from deep
inelastic scattering can neither be reproduced by models which are based on
leading order alpha_s QCD matrix elements and parton showers nor by
next-to-leading order calculations. The measurement of forward jet cross
sections has been suggested as a promising probe of new small x dynamics and
the question is whether these data provide an indication of this. The same
question arises for other experimental data in deep inelastic scattering at
small x which can not be described by conventional models for deep inelastic
scattering. In this paper the influence of resolved photon processes has been
investigated and it has been studied to what extent such processes are able to
reproduce the data. It is shown that two DGLAP evolution chains from the hard
scattering process towards the proton and the photon, respectively, are
sufficient to describe effects, observed in the HERA data, which have been
attributed to BFKL dynamics.
|
[
{
"created": "Wed, 20 May 1998 14:21:43 GMT",
"version": "v1"
},
{
"created": "Fri, 22 May 1998 08:22:26 GMT",
"version": "v2"
}
] |
2007-05-23
|
[
[
"Jung",
"H.",
"",
"Lund"
],
[
"Joensson",
"L.",
"",
"Lund"
],
[
"Kuester",
"H.",
"",
"Lund"
]
] |
It has been found that recent results on forward jet production from deep inelastic scattering can neither be reproduced by models which are based on leading order alpha_s QCD matrix elements and parton showers nor by next-to-leading order calculations. The measurement of forward jet cross sections has been suggested as a promising probe of new small x dynamics and the question is whether these data provide an indication of this. The same question arises for other experimental data in deep inelastic scattering at small x which can not be described by conventional models for deep inelastic scattering. In this paper the influence of resolved photon processes has been investigated and it has been studied to what extent such processes are able to reproduce the data. It is shown that two DGLAP evolution chains from the hard scattering process towards the proton and the photon, respectively, are sufficient to describe effects, observed in the HERA data, which have been attributed to BFKL dynamics.
|
1112.2705
|
David Morrissey
|
Yuk Fung Chan, Matthew Low, David E. Morrissey and Andrew P. Spray
|
LHC Signatures of a Minimal Supersymmetric Hidden Valley
|
45 pages, 15 figures; typos corrected but conclusions unchanged
|
Journal of High Energy Physics, Volume 2012, Number 5 (2012), 155
|
10.1007/JHEP05(2012)155
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We investigate the LHC signals of a minimal supersymmetric hidden valley. Our
theory consists of the supersymmetric Standard Model along with a light hidden
U(1)_x gauge multiplet and a pair of hidden chiral superfields that
spontaneously break the new Abelian gauge symmetry near a GeV. The visible and
hidden sectors interact exclusively through supersymmetric gauge kinetic
mixing. We perform a thorough examination of the hidden decay cascades
initiated by the lightest Standard Model superpartner and we study the range of
LHC signals they can produce. In particular, we find parameter regions that
give rise to missing energy, single and multiple lepton jets, and displaced
vertices. Given the simplicity of the underlying theory and the broad range of
collider signals it can produce, we propose that this model is a useful
benchmark for LHC studies of (supersymmetric) hidden valleys.
|
[
{
"created": "Mon, 12 Dec 2011 21:00:03 GMT",
"version": "v1"
},
{
"created": "Wed, 27 Jun 2012 19:23:14 GMT",
"version": "v2"
},
{
"created": "Fri, 31 Jan 2014 00:59:17 GMT",
"version": "v3"
}
] |
2014-02-03
|
[
[
"Chan",
"Yuk Fung",
""
],
[
"Low",
"Matthew",
""
],
[
"Morrissey",
"David E.",
""
],
[
"Spray",
"Andrew P.",
""
]
] |
We investigate the LHC signals of a minimal supersymmetric hidden valley. Our theory consists of the supersymmetric Standard Model along with a light hidden U(1)_x gauge multiplet and a pair of hidden chiral superfields that spontaneously break the new Abelian gauge symmetry near a GeV. The visible and hidden sectors interact exclusively through supersymmetric gauge kinetic mixing. We perform a thorough examination of the hidden decay cascades initiated by the lightest Standard Model superpartner and we study the range of LHC signals they can produce. In particular, we find parameter regions that give rise to missing energy, single and multiple lepton jets, and displaced vertices. Given the simplicity of the underlying theory and the broad range of collider signals it can produce, we propose that this model is a useful benchmark for LHC studies of (supersymmetric) hidden valleys.
|
1811.03572
|
Subhayan Mandal
|
Karam Chand and Subhayan Mandal
|
Probing Pseudoscalars with Pulsar Polarisation Data Sets
|
16 pages, 3 figures, 5 tables
| null | null | null |
hep-ph astro-ph.HE
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Recently a data set containing linear and circular polarisation information
of a collection of six hundred pulsars has been released. The operative radio
wavelength for the same was 21 cm. Pulsars radio emission process is modelled
either with synchroton / superconducting self-Compton route or with curvature
radiation route. These theories fall short of accounting for the circular
polarisation observed, as they are predisposed towards producing, solely,
linear polarisation. Here we invoke (pseudo)scalars and their interaction with
photons mediated by colossal magnetic fields of pulsars, to account for the
circular part of polarisation data. This enables us to estimate the
pseudoscalar parameters such as its coupling to photons and its mass in
conjunction as product. To obtain these values separately, we turn our
attention to recent observation on 47 pulsars, whose absolute polarisation
position angles have been made available. Except, a third of the latter set,
the rest of it overlaps with the expansive former data set on polarisation type
\& degree. This helps us figure out, both the pseudoscalar parameters
individually, that we report here.
|
[
{
"created": "Thu, 8 Nov 2018 17:52:27 GMT",
"version": "v1"
},
{
"created": "Wed, 30 Oct 2019 03:35:09 GMT",
"version": "v2"
},
{
"created": "Fri, 8 Nov 2019 04:31:47 GMT",
"version": "v3"
}
] |
2019-11-11
|
[
[
"Chand",
"Karam",
""
],
[
"Mandal",
"Subhayan",
""
]
] |
Recently a data set containing linear and circular polarisation information of a collection of six hundred pulsars has been released. The operative radio wavelength for the same was 21 cm. Pulsars radio emission process is modelled either with synchroton / superconducting self-Compton route or with curvature radiation route. These theories fall short of accounting for the circular polarisation observed, as they are predisposed towards producing, solely, linear polarisation. Here we invoke (pseudo)scalars and their interaction with photons mediated by colossal magnetic fields of pulsars, to account for the circular part of polarisation data. This enables us to estimate the pseudoscalar parameters such as its coupling to photons and its mass in conjunction as product. To obtain these values separately, we turn our attention to recent observation on 47 pulsars, whose absolute polarisation position angles have been made available. Except, a third of the latter set, the rest of it overlaps with the expansive former data set on polarisation type \& degree. This helps us figure out, both the pseudoscalar parameters individually, that we report here.
|
hep-ph/9510277
|
Junji Hisano
|
J.Hisano (TIT, ITP) and T.Yanagida (Univ. of Tokyo, TIT)
|
An N=2 SUSY Gauge Model for Dynamical Breaking of the Grand Unified
SU(5) Symmetry
|
7 pages
|
Mod.Phys.Lett.A10:3097-3102,1995
|
10.1142/S0217732395003240
|
NSF-ITP-95-124,TIT-HEP-303,UT-726
|
hep-ph
| null |
We construct an extension of the recently proposed dynamical model for the
breaking of SU(5)$_{\rm GUT}$ gauge symmetry, in which a pair of massless
chiral supermultiplets for Higgs doublets are naturally obtained. We point out
that a model at a specific point in the parameter space of superpotential is
regarded as a low-energy effective theory of an N=2 supersymmetric gauge model
for the strongly interacting hypercolor sector.
|
[
{
"created": "Wed, 11 Oct 1995 21:03:32 GMT",
"version": "v1"
}
] |
2008-11-26
|
[
[
"Hisano",
"J.",
"",
"TIT, ITP"
],
[
"Yanagida",
"T.",
"",
"Univ. of Tokyo, TIT"
]
] |
We construct an extension of the recently proposed dynamical model for the breaking of SU(5)$_{\rm GUT}$ gauge symmetry, in which a pair of massless chiral supermultiplets for Higgs doublets are naturally obtained. We point out that a model at a specific point in the parameter space of superpotential is regarded as a low-energy effective theory of an N=2 supersymmetric gauge model for the strongly interacting hypercolor sector.
|
1807.08938
|
Fernand M Renard
|
Fernand M. Renard
|
Z polarization in $e^+e^-\to ZWW $ for testing special interactions of
massive particles
|
12 pages, 6 figures
| null | null | null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We show that the $ZWW$ production process may give complementary informations
about scale dependent heavy particle masses and possible final state
interactions as compared to previously studied top quark production processes.
We illustrate the $p_Z$ distribution of the rate of longitudinal $Z_L$
component showing its sensitivity to these effects which may arise from heavy
particle substructure or a dark matter (DM) environment.
|
[
{
"created": "Tue, 24 Jul 2018 07:46:56 GMT",
"version": "v1"
}
] |
2018-07-25
|
[
[
"Renard",
"Fernand M.",
""
]
] |
We show that the $ZWW$ production process may give complementary informations about scale dependent heavy particle masses and possible final state interactions as compared to previously studied top quark production processes. We illustrate the $p_Z$ distribution of the rate of longitudinal $Z_L$ component showing its sensitivity to these effects which may arise from heavy particle substructure or a dark matter (DM) environment.
|
hep-ph/0003031
|
Kimball A. Milton
|
K.A. Milton, I.L. Solovtsov, and O.P. Solovtsova
|
Timelike and spacelike QCD characteristics of the $e^+e^-$ annihilation
process
|
11 pages, 4 eps figures, revtex
|
Eur.Phys.J.C13:497-502,2000
|
10.1007/s100520050712
|
OKHEP-99-07
|
hep-ph
| null |
We consider the Adler $D$-function, which is defined in the spacelike region,
and the $e^+e^-$ annihilation ratio smeared, according to the Poggio, Quinn,
and Weinberg method, which is determined for timelike argument. We show that
the method of the nonperturbative $a$-expansion allows one to describe these
Euclidean and Minkowskian characteristics of the process of $e^+e^-$
annihilation down to the lowest energy scales.
|
[
{
"created": "Fri, 3 Mar 2000 23:23:26 GMT",
"version": "v1"
}
] |
2011-09-13
|
[
[
"Milton",
"K. A.",
""
],
[
"Solovtsov",
"I. L.",
""
],
[
"Solovtsova",
"O. P.",
""
]
] |
We consider the Adler $D$-function, which is defined in the spacelike region, and the $e^+e^-$ annihilation ratio smeared, according to the Poggio, Quinn, and Weinberg method, which is determined for timelike argument. We show that the method of the nonperturbative $a$-expansion allows one to describe these Euclidean and Minkowskian characteristics of the process of $e^+e^-$ annihilation down to the lowest energy scales.
|
hep-ph/0507134
|
Yuri V. Kovchegov
|
Yuri V. Kovchegov
|
Thoughts on Non-Perturbative Thermalization and Jet Quenching in Heavy
Ion Collisions
|
26 pages, no figures
|
Nucl.Phys. A764 (2006) 476-497
|
10.1016/j.nuclphysa.2005.09.010
| null |
hep-ph nucl-th
| null |
We start by presenting physical arguments for the impossibility of
perturbative thermalization leading to (non-viscous) Bjorken hydrodynamic
description of heavy ion collisions. These arguments are complimentary to our
more formal argument presented in [hep-ph/0503038]. We argue that the success
of hydrodynamic models in describing the quark-gluon system produced in heavy
ion collisions could only be due to non-perturbative strong coupling effects.
We continue by studying non-perturbative effects in heavy ion collisions at
high energies. We model non-perturbative phenomena by an instanton ensemble. We
show that non-perturbative instanton vacuum fields may significantly contribute
to jet quenching in nuclear collisions. At the same time, the instanton
ensemble contribution to thermalization is likely to be rather weak, leading to
non-perturbative thermalization time comparable to the time of hadronization.
This example illustrates that jet quenching is not necessarily a signal of a
thermalized medium. Indeed, since the instanton models do not capture all the
effects of QCD vacuum (e.g. they do not account for confinement), there may be
other non-perturbative effects facilitating thermalization of the system.
|
[
{
"created": "Mon, 11 Jul 2005 22:25:29 GMT",
"version": "v1"
}
] |
2009-11-11
|
[
[
"Kovchegov",
"Yuri V.",
""
]
] |
We start by presenting physical arguments for the impossibility of perturbative thermalization leading to (non-viscous) Bjorken hydrodynamic description of heavy ion collisions. These arguments are complimentary to our more formal argument presented in [hep-ph/0503038]. We argue that the success of hydrodynamic models in describing the quark-gluon system produced in heavy ion collisions could only be due to non-perturbative strong coupling effects. We continue by studying non-perturbative effects in heavy ion collisions at high energies. We model non-perturbative phenomena by an instanton ensemble. We show that non-perturbative instanton vacuum fields may significantly contribute to jet quenching in nuclear collisions. At the same time, the instanton ensemble contribution to thermalization is likely to be rather weak, leading to non-perturbative thermalization time comparable to the time of hadronization. This example illustrates that jet quenching is not necessarily a signal of a thermalized medium. Indeed, since the instanton models do not capture all the effects of QCD vacuum (e.g. they do not account for confinement), there may be other non-perturbative effects facilitating thermalization of the system.
|
2309.10043
|
Jordan Koechler
|
Jordan Koechler
|
X-rays constraints on sub-GeV Dark Matter
|
Contribution to the 34th Rencontres de Blois on Particle Physics and
Cosmology (Blois 2023), the XVIII International Conference on Topics in
Astroparticle and Underground Physics (TAUP 2023) and TeV Particle
Astrophysics (TeVPA) 2023
| null |
10.22323/1.441.0044
| null |
hep-ph astro-ph.CO astro-ph.HE
|
http://creativecommons.org/licenses/by-nc-nd/4.0/
|
We present updated constraints on 'light' Dark Matter (DM) particles with
masses between 1 MeV and 5 GeV. In this range, we can expect DM-produced
$e^\pm$ pairs to up-scatter low-energy ambient photons in the Milky Way via the
Inverse Compton process, and produce a flux of X-rays that can be probed by a
range of space observatories. Using diffuse X-ray data from XMM-Newton,
INTEGRAL, NuSTAR and Suzaku, we compute the strongest constraints to date on
annihilating DM for 200 MeV $< m_{\rm DM} <$ 5 GeV and decaying DM for 100 MeV
$< m_{\rm DM} <$ 5 GeV.
|
[
{
"created": "Mon, 18 Sep 2023 18:00:18 GMT",
"version": "v1"
},
{
"created": "Tue, 16 Jan 2024 08:51:06 GMT",
"version": "v2"
}
] |
2024-01-17
|
[
[
"Koechler",
"Jordan",
""
]
] |
We present updated constraints on 'light' Dark Matter (DM) particles with masses between 1 MeV and 5 GeV. In this range, we can expect DM-produced $e^\pm$ pairs to up-scatter low-energy ambient photons in the Milky Way via the Inverse Compton process, and produce a flux of X-rays that can be probed by a range of space observatories. Using diffuse X-ray data from XMM-Newton, INTEGRAL, NuSTAR and Suzaku, we compute the strongest constraints to date on annihilating DM for 200 MeV $< m_{\rm DM} <$ 5 GeV and decaying DM for 100 MeV $< m_{\rm DM} <$ 5 GeV.
|
2308.01347
|
Aidan Reilly
|
Aidan Reilly and Natalia Toro
|
Ultraviolet Running Constraints on Low Mass Dark Sectors
|
30 pages, 12 figures, 2 tables; added references in section 3; minor
revisions
| null | null | null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We analyze the UV breakdown of Sub-GeV dark matter models that live in a new,
dark U(1) sector. Many of these models include a scalar field, which is either
the dark matter itself or a dark Higgs field that generates mass terms for the
dark matter particle via spontaneous symmetry breaking. A quartic self coupling
of this scalar field is generically allowed, and we show that its running is
largely governed by the strength of the U(1) gauge field, $\alpha_D$.
Furthermore, it consistently has a lower Landau pole than the gauge coupling.
Link fields, which couple to both the dark sector and the Standard Model (SM),
connect these Landau poles to constraints on SM charged particles. Current LHC
constraints on link fields are compatible with $\alpha_D \lesssim 0.5 - 1$ for
most of the mass range in most models, while smaller values, $\alpha_D \lesssim
0.15$, are favored for Majorana DM.
|
[
{
"created": "Wed, 2 Aug 2023 18:00:04 GMT",
"version": "v1"
},
{
"created": "Tue, 5 Sep 2023 02:56:28 GMT",
"version": "v2"
},
{
"created": "Tue, 14 Nov 2023 23:28:32 GMT",
"version": "v3"
}
] |
2023-11-16
|
[
[
"Reilly",
"Aidan",
""
],
[
"Toro",
"Natalia",
""
]
] |
We analyze the UV breakdown of Sub-GeV dark matter models that live in a new, dark U(1) sector. Many of these models include a scalar field, which is either the dark matter itself or a dark Higgs field that generates mass terms for the dark matter particle via spontaneous symmetry breaking. A quartic self coupling of this scalar field is generically allowed, and we show that its running is largely governed by the strength of the U(1) gauge field, $\alpha_D$. Furthermore, it consistently has a lower Landau pole than the gauge coupling. Link fields, which couple to both the dark sector and the Standard Model (SM), connect these Landau poles to constraints on SM charged particles. Current LHC constraints on link fields are compatible with $\alpha_D \lesssim 0.5 - 1$ for most of the mass range in most models, while smaller values, $\alpha_D \lesssim 0.15$, are favored for Majorana DM.
|
1609.03895
|
Vo Van Vien
|
V. V. Vien and H. N. Long
|
Lepton mass and mixing in a simple extension of the Standard Model based
on T7 flavor symmetry
|
23 pages, 6 figures
|
Physics of Atomic Nuclei, Vol. 82, No 2, (2019), pp. 168--182
|
10.1134/S1063778819020133
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
A simple Standard Model Extension based on $T_7$ flavor symmetry which
accommodates lepton mass and mixing with non-zero $\theta_{13}$ and CP
violation phase is proposed. At the tree- level, the realistic lepton mass and
mixing pattern is derived through the spontaneous symmetry breaking by just one
vacuum expectation value ($v$) which is the same as in the Standard Model.
Neutrinos get small masses from one $SU(2)_L$ doublet and two $SU(2)_L$
singlets in which one being in $\underline{1}$ and the two others in
$\underline{3}$ and $\underline{3}^*$ under $T_7$ , respectively. The model
also gives a remarkable prediction of Dirac CP violation
$\delta_{CP}=172.598^\circ$ in both normal and inverted hierarchies which is
still missing in the neutrino mixing matrix.
|
[
{
"created": "Tue, 13 Sep 2016 15:25:13 GMT",
"version": "v1"
}
] |
2019-05-01
|
[
[
"Vien",
"V. V.",
""
],
[
"Long",
"H. N.",
""
]
] |
A simple Standard Model Extension based on $T_7$ flavor symmetry which accommodates lepton mass and mixing with non-zero $\theta_{13}$ and CP violation phase is proposed. At the tree- level, the realistic lepton mass and mixing pattern is derived through the spontaneous symmetry breaking by just one vacuum expectation value ($v$) which is the same as in the Standard Model. Neutrinos get small masses from one $SU(2)_L$ doublet and two $SU(2)_L$ singlets in which one being in $\underline{1}$ and the two others in $\underline{3}$ and $\underline{3}^*$ under $T_7$ , respectively. The model also gives a remarkable prediction of Dirac CP violation $\delta_{CP}=172.598^\circ$ in both normal and inverted hierarchies which is still missing in the neutrino mixing matrix.
|
1107.4473
|
Marcin Badziak
|
Marcin Badziak
|
Yukawa unification in SUSY SO(10) for mu<0 consistent with muon g-2 and
b->s gamma
|
Talk given at 46th Rencontres de Moriond on Electroweak Interactions
and Unified Theories, 13-20 March 2011
| null | null |
Cavendish-HEP-11/11, DAMTP-2011-37
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
It is shown that top-bottom-tau Yukawa unification for \mu<0 can be
consistent with (g-2)_\mu and b->s \gamma. This happens for non-universal
gaugino masses which are assumed to be generated by the F-term vev in a
54-dimensional representation of SO(10). The requirement of (g-2)_\mu and b->s
\gamma being within 2\sigma from the experimental central values, together with
the correct relic abundance of neutralinos, leads to rather definite
predictions for sparticle spectrum. In particular, the gluino mass is predicted
to be between 500 and 700 GeV or between 900 GeV and 1.6 TeV.
|
[
{
"created": "Fri, 22 Jul 2011 10:36:04 GMT",
"version": "v1"
}
] |
2011-07-25
|
[
[
"Badziak",
"Marcin",
""
]
] |
It is shown that top-bottom-tau Yukawa unification for \mu<0 can be consistent with (g-2)_\mu and b->s \gamma. This happens for non-universal gaugino masses which are assumed to be generated by the F-term vev in a 54-dimensional representation of SO(10). The requirement of (g-2)_\mu and b->s \gamma being within 2\sigma from the experimental central values, together with the correct relic abundance of neutralinos, leads to rather definite predictions for sparticle spectrum. In particular, the gluino mass is predicted to be between 500 and 700 GeV or between 900 GeV and 1.6 TeV.
|
1502.04589
|
Nan Su
|
Nan Su
|
Recent progress in hard-thermal-loop QCD thermodynamics and collective
excitations
|
18 pages, 7 figures; Invited review for International Journal of
Modern Physics A; v2, references updated and typos corrected, published
version
|
Int. J. Mod. Phys. A, Vol. 30, 1530025 (2015)
|
10.1142/S0217751X15300252
|
BI-TP 2015/08
|
hep-ph hep-lat hep-th nucl-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
I review recent developments in QCD thermodynamics and collective excitations
from the hard-thermal-loop effective theory. I begin by motivating the
discussion with open questions from heavy-ion collisions. I then discuss a
finite-temperature and -density calculation of QCD thermodynamics at NNLO from
the hard-thermal-loop perturbation theory. Finally I discuss a recent
exploration of generalizing the hard-thermal-loop framework to the
(chromo)magnetic scale $g^2T$, from which a novel massless mode is uncovered.
|
[
{
"created": "Mon, 16 Feb 2015 16:02:53 GMT",
"version": "v1"
},
{
"created": "Fri, 27 Mar 2015 21:28:43 GMT",
"version": "v2"
}
] |
2015-03-31
|
[
[
"Su",
"Nan",
""
]
] |
I review recent developments in QCD thermodynamics and collective excitations from the hard-thermal-loop effective theory. I begin by motivating the discussion with open questions from heavy-ion collisions. I then discuss a finite-temperature and -density calculation of QCD thermodynamics at NNLO from the hard-thermal-loop perturbation theory. Finally I discuss a recent exploration of generalizing the hard-thermal-loop framework to the (chromo)magnetic scale $g^2T$, from which a novel massless mode is uncovered.
|
hep-ph/0205129
|
Giacomo Cacciapaglia
|
G.Cacciapaglia (Scuola Normale Superiore & INFN, Pisa)
|
Higgs boson decay rate into gluons in a 5 dimensional calculable model
|
2 pp, contribution to the XXXVIIth Rencontres de Moriond,
"Electroweak interactions and unified theories", Les Arcs, France, 9-16 Mar
2002
| null | null | null |
hep-ph
| null |
In an extension of the Standard Model with one compact extra dimension and
N=1 supersymmetry, we compute the Higgs boson decay rate into two gluons,
relevant to the Higgs production in hadronic collisions. We find that at one
loop the decay width is significantly suppressed with respect to the SM. In
particular, for a compactification radius 1/R=370 /pm 70 GeV and a Higgs mass
m_H = 127 /pm 8 GeV we find it to be less than 15% of the SM result.
|
[
{
"created": "Mon, 13 May 2002 17:08:49 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Cacciapaglia",
"G.",
"",
"Scuola Normale Superiore & INFN, Pisa"
]
] |
In an extension of the Standard Model with one compact extra dimension and N=1 supersymmetry, we compute the Higgs boson decay rate into two gluons, relevant to the Higgs production in hadronic collisions. We find that at one loop the decay width is significantly suppressed with respect to the SM. In particular, for a compactification radius 1/R=370 /pm 70 GeV and a Higgs mass m_H = 127 /pm 8 GeV we find it to be less than 15% of the SM result.
|
hep-ph/0501003
|
Anisovich Vladimir V.
|
V.V. Anisovich, M.A. Matveev, J. Nyiri, A.V. Sarantsev
|
Determination of the quarkonium--gluonium content of the isoscalar
tensor resonances $f_2(1920)$, $f_2(2020)$, $f_2(2240)$, $f_2(2300)$ and of
the broad state $f_2(2000)$ based on decay couplings to
$\pi^0\pi^0,\eta\eta,\eta\eta'$
|
9 pages, 4 figures
| null | null | null |
hep-ph
| null |
In the reactions $p\bar p\to\pi^0\pi^0,\eta\eta,\eta\eta'$ there are four
relatively narrow resonances $f_2(1920)$, $f_2(2020)$, $f_2(2240)$,
$f_2(2300)$, and a broad one $f_2(2000)$ in the mass region 1990--2400 MeV. In
the framework of quark combinatorics we carry out an analysis of the decay
constants for all five resonances. It is shown that the relations for the decay
constants corresponding to the broad resonance
$f_2(2000)\to\pi^0\pi^0,\eta\eta, \eta\eta'$ are the same as those
corresponding to a glueball. An additional argument in favour of the
glueball--nature of $f_2(2000)$ is the fact that $f_2(1920)$, $f_2(2020)$,
$f_2(2240)$, $f_2(2300)$ fit well the $q\bar q$ trajectories in the
$(n,M^2)$-plane (where $n$ is the radial quantum number), while the broad
$f_2(2000)$ resonance turns out to be an unnecessary extra state for these
trajectories.
|
[
{
"created": "Sat, 1 Jan 2005 14:06:38 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Anisovich",
"V. V.",
""
],
[
"Matveev",
"M. A.",
""
],
[
"Nyiri",
"J.",
""
],
[
"Sarantsev",
"A. V.",
""
]
] |
In the reactions $p\bar p\to\pi^0\pi^0,\eta\eta,\eta\eta'$ there are four relatively narrow resonances $f_2(1920)$, $f_2(2020)$, $f_2(2240)$, $f_2(2300)$, and a broad one $f_2(2000)$ in the mass region 1990--2400 MeV. In the framework of quark combinatorics we carry out an analysis of the decay constants for all five resonances. It is shown that the relations for the decay constants corresponding to the broad resonance $f_2(2000)\to\pi^0\pi^0,\eta\eta, \eta\eta'$ are the same as those corresponding to a glueball. An additional argument in favour of the glueball--nature of $f_2(2000)$ is the fact that $f_2(1920)$, $f_2(2020)$, $f_2(2240)$, $f_2(2300)$ fit well the $q\bar q$ trajectories in the $(n,M^2)$-plane (where $n$ is the radial quantum number), while the broad $f_2(2000)$ resonance turns out to be an unnecessary extra state for these trajectories.
|
1702.01099
|
Danny Marfatia
|
Alakabha Datta, Jiajun Liao, Danny Marfatia
|
A light $Z^\prime$ for the $R_K$ puzzle and nonstandard neutrino
interactions
|
5 pages, 2 figures. Typos corrected
|
Phys. Lett. B 768 : 265-269 (2017)
|
10.1016/j.physletb.2017.02.058
| null |
hep-ph hep-ex
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We show that the $R_K$ puzzle in LHCb data and the discrepancy in the
anomalous magnetic moment of the muon can be simultaneously explained if a 10
MeV mass $Z^\prime$ boson couples to the muon but not the electron, and that
clear evidence of the nonstandard matter interactions of neutrinos induced by
this coupling may be found at DUNE.
|
[
{
"created": "Fri, 3 Feb 2017 18:08:18 GMT",
"version": "v1"
},
{
"created": "Sat, 25 Feb 2017 17:57:33 GMT",
"version": "v2"
},
{
"created": "Sun, 23 Apr 2017 19:16:06 GMT",
"version": "v3"
}
] |
2017-04-25
|
[
[
"Datta",
"Alakabha",
""
],
[
"Liao",
"Jiajun",
""
],
[
"Marfatia",
"Danny",
""
]
] |
We show that the $R_K$ puzzle in LHCb data and the discrepancy in the anomalous magnetic moment of the muon can be simultaneously explained if a 10 MeV mass $Z^\prime$ boson couples to the muon but not the electron, and that clear evidence of the nonstandard matter interactions of neutrinos induced by this coupling may be found at DUNE.
|
2312.14679
|
Andreas Ringwald
|
Andreas Ringwald
|
Prospects to scrutinise or smash SM*A*S*H
|
13 pages, 9 pages, contribution to the proceedings of the 1st General
Meeting and 1st Training School of the COST Action COSMIC WISPers
(COSMICWISPers)
| null | null |
DESY-23-225
|
hep-ph astro-ph.CO hep-ex
|
http://creativecommons.org/licenses/by/4.0/
|
SM*A*S*H is an extension of the Standard Model of particle physics which has
just the minimal number of fields in order to solve six puzzles of particle
physics and cosmology in one smash: vacuum stability, inflation, baryon
asymmetry, neutrino masses, strong CP, and dark matter. The parameters of
SM*A*S*H are constrained by symmetries and requirements to solve these puzzles.
This provides various firm predictions for observables which can be confronted
with experiments. We discuss the prospects and timeline to scrutinise or smash
SM*A*S*H by cosmic microwave background polarisation experiments, axion
haloscopes, and future space-borne gravitational wave detectors.
|
[
{
"created": "Fri, 22 Dec 2023 13:30:42 GMT",
"version": "v1"
}
] |
2023-12-25
|
[
[
"Ringwald",
"Andreas",
""
]
] |
SM*A*S*H is an extension of the Standard Model of particle physics which has just the minimal number of fields in order to solve six puzzles of particle physics and cosmology in one smash: vacuum stability, inflation, baryon asymmetry, neutrino masses, strong CP, and dark matter. The parameters of SM*A*S*H are constrained by symmetries and requirements to solve these puzzles. This provides various firm predictions for observables which can be confronted with experiments. We discuss the prospects and timeline to scrutinise or smash SM*A*S*H by cosmic microwave background polarisation experiments, axion haloscopes, and future space-borne gravitational wave detectors.
|
0912.4955
|
Laszlo Jenkovszky
|
R. Fiore, L. Jenkovszky, E. Kuraev, A. Lengyel, Z. Tarics
|
Predictions for high-energy pp and \bar pp scattering from a finite sum
of gluon ladders
|
15 pages, 2 figures
|
Phys.Rev.D81:056001,2010
|
10.1103/PhysRevD.81.056001
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
An eikonalized elastic proton-proton and proton-antiproton scattering
amplitude F(s,t), calculated from QCD as a finite sum of gluon ladders, is
compared with the existing experimental data on the total cross section and the
ratio \rho(s,0)=Re F(s,0)/Im F(s,0) of the real part to the imaginary part of
the forward amplitude. Predictions for the expected LHC energies are given.
|
[
{
"created": "Fri, 25 Dec 2009 09:16:30 GMT",
"version": "v1"
}
] |
2010-04-06
|
[
[
"Fiore",
"R.",
""
],
[
"Jenkovszky",
"L.",
""
],
[
"Kuraev",
"E.",
""
],
[
"Lengyel",
"A.",
""
],
[
"Tarics",
"Z.",
""
]
] |
An eikonalized elastic proton-proton and proton-antiproton scattering amplitude F(s,t), calculated from QCD as a finite sum of gluon ladders, is compared with the existing experimental data on the total cross section and the ratio \rho(s,0)=Re F(s,0)/Im F(s,0) of the real part to the imaginary part of the forward amplitude. Predictions for the expected LHC energies are given.
|
1112.0682
|
Emiliano Molinaro
|
Emiliano Molinaro
|
Indirect Signatures of Type I See-Saw Scenarios
|
4 pages, 2 figures. Contributions to the Proceedings of the 12th
International Conference on Topics in Astroparticle and Underground Physics
(TAUP 2011), Munich, Germany, 5-9 September 2011
| null |
10.1088/1742-6596/375/1/042002
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We consider the low energy constraints that can be applied to type I see-saw
extensions of the Standard Model in which the right-handed neutrinos are taken
at the electroweak scale. In the reported scenarios, the flavour structure of
the charged current and neutral current weak interactions of the Standard Model
leptons with the heavy right-handed neutrinos is essentially determined by the
neutrino oscillation parameters. In this case, correlations among different
measurable phenomena in the lepton sector may provide compelling indirect
evidence of low energy see-saw mechanism of neutrino mass generation.
|
[
{
"created": "Sat, 3 Dec 2011 18:55:02 GMT",
"version": "v1"
}
] |
2015-06-03
|
[
[
"Molinaro",
"Emiliano",
""
]
] |
We consider the low energy constraints that can be applied to type I see-saw extensions of the Standard Model in which the right-handed neutrinos are taken at the electroweak scale. In the reported scenarios, the flavour structure of the charged current and neutral current weak interactions of the Standard Model leptons with the heavy right-handed neutrinos is essentially determined by the neutrino oscillation parameters. In this case, correlations among different measurable phenomena in the lepton sector may provide compelling indirect evidence of low energy see-saw mechanism of neutrino mass generation.
|
2308.02240
|
Alexey Drutskoy
|
E. Antonov, A. Drutskoy, M. Dubinin
|
A possible search for Majorana neutrinos at future lepton colliders
|
8 pages, 5 figures, 3 tables, published in JETP Letters
| null |
10.1134/S0021364023602518
| null |
hep-ph hep-ex
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We discuss the process $\ell^+\ell^- \to N W^{\pm} \ell^{\mp}$, where $N$ is
a heavy Majorana neutrino and $\ell = e, \mu$. Large cross sections are
expected for these processes at high center-of-mass energies, which can be
reached at future lepton-lepton colliders. The Monte Carlo simulation of the
studied processes is produced within the framework of the seesaw type-I model,
where the Majorana neutrinos (or heavy neutral leptons, HNL), are introduced in
the standard leptonic sector. Recently the possibility to search for the direct
HNL production was studied in the $\ell^+\ell^- \to N \nu_{\ell}$ process with
the subsequent decay $N \to W^{\pm} \ell^{\mp}$. In this paper we investigate
an alternative process $\ell^+\ell^- \to N W^{\pm} \ell^{\mp} \to
W^{\pm}W^{\pm}\,\ell^{\mp}\,\ell^{\mp}$ with the lepton number violation by two
units. The similar processes appear in collisions with the same-sign beams,
$e^-e^- \to N W^-\,e^- \to W^-\,W^-\,e^+\,e^-$ or $\mu^+\mu^+ \to N W^+\,\mu^+
\to W^+\,W^+\,\mu^+\,\mu^-$. The cross sections of the processes under
consideration are enhanced by the soft photon exchange in the $t$-channel. We
calculate the cross sections for the signals and potential Standard Model
backgrounds for the $e^+e^-$ beam collisions at the 1 TeV center-of-mass energy
and the $\mu^+\mu^-$ collisions at 3 TeV and 10 TeV. Due to the diagrams with
soft $t$-channel photons and respective interference the promptly emitted
leptons are produced in the direction close to the corresponding beam. These
leptons will be lost in the beam pipe or badly measured by forward detectors.
However, the signal events can be well separated from backgrounds using the
rest of the event containing the $WW\ell$ particles. Finally, the expected
upper limits on the mixing parameters $|V_{\ell N}|^2$ as a function of M($N$)
are calculated.
|
[
{
"created": "Fri, 4 Aug 2023 10:39:31 GMT",
"version": "v1"
},
{
"created": "Thu, 28 Sep 2023 15:49:52 GMT",
"version": "v2"
}
] |
2023-09-29
|
[
[
"Antonov",
"E.",
""
],
[
"Drutskoy",
"A.",
""
],
[
"Dubinin",
"M.",
""
]
] |
We discuss the process $\ell^+\ell^- \to N W^{\pm} \ell^{\mp}$, where $N$ is a heavy Majorana neutrino and $\ell = e, \mu$. Large cross sections are expected for these processes at high center-of-mass energies, which can be reached at future lepton-lepton colliders. The Monte Carlo simulation of the studied processes is produced within the framework of the seesaw type-I model, where the Majorana neutrinos (or heavy neutral leptons, HNL), are introduced in the standard leptonic sector. Recently the possibility to search for the direct HNL production was studied in the $\ell^+\ell^- \to N \nu_{\ell}$ process with the subsequent decay $N \to W^{\pm} \ell^{\mp}$. In this paper we investigate an alternative process $\ell^+\ell^- \to N W^{\pm} \ell^{\mp} \to W^{\pm}W^{\pm}\,\ell^{\mp}\,\ell^{\mp}$ with the lepton number violation by two units. The similar processes appear in collisions with the same-sign beams, $e^-e^- \to N W^-\,e^- \to W^-\,W^-\,e^+\,e^-$ or $\mu^+\mu^+ \to N W^+\,\mu^+ \to W^+\,W^+\,\mu^+\,\mu^-$. The cross sections of the processes under consideration are enhanced by the soft photon exchange in the $t$-channel. We calculate the cross sections for the signals and potential Standard Model backgrounds for the $e^+e^-$ beam collisions at the 1 TeV center-of-mass energy and the $\mu^+\mu^-$ collisions at 3 TeV and 10 TeV. Due to the diagrams with soft $t$-channel photons and respective interference the promptly emitted leptons are produced in the direction close to the corresponding beam. These leptons will be lost in the beam pipe or badly measured by forward detectors. However, the signal events can be well separated from backgrounds using the rest of the event containing the $WW\ell$ particles. Finally, the expected upper limits on the mixing parameters $|V_{\ell N}|^2$ as a function of M($N$) are calculated.
|
2401.12571
|
Zhi-Gang Wang
|
Zhi-Gang Wang
|
The $B_c$ meson and its scalar cousin with the QCD sum rules
|
15 pages, 10 figures
|
Chin. Phys. C48 (2024) 103104
|
10.1088/1674-1137/ad5a71
| null |
hep-ph
|
http://creativecommons.org/licenses/by/4.0/
|
In the present work, we use optical theorem to calculate the next-to-leading
order corrections to the QCD spectral densities directly in the QCD sum rules
for the pseudoscalar and scalar $B_c$ mesons. We take the experimental data as
guides to perform updated analysis, and obtain the masses and decay constants,
especially the decay constants, which are the fundamental input parameters in
the high energy physics, therefore the pure leptonic decay widths, which can be
confronted to the experimental data in the future.
|
[
{
"created": "Tue, 23 Jan 2024 09:03:54 GMT",
"version": "v1"
},
{
"created": "Sat, 20 Apr 2024 09:09:00 GMT",
"version": "v2"
},
{
"created": "Thu, 6 Jun 2024 13:04:34 GMT",
"version": "v3"
}
] |
2024-08-13
|
[
[
"Wang",
"Zhi-Gang",
""
]
] |
In the present work, we use optical theorem to calculate the next-to-leading order corrections to the QCD spectral densities directly in the QCD sum rules for the pseudoscalar and scalar $B_c$ mesons. We take the experimental data as guides to perform updated analysis, and obtain the masses and decay constants, especially the decay constants, which are the fundamental input parameters in the high energy physics, therefore the pure leptonic decay widths, which can be confronted to the experimental data in the future.
|
2102.06159
|
Daniel Adamiak
|
Daniel Adamiak, Yuri V. Kovchegov, W. Melnitchouk, Daniel Pitonyak,
Nobuo Sato, Matthew D. Sievert
|
First analysis of world polarized DIS data with small-$x$ helicity
evolution
|
7 pages, 5 figures; v2: Discussion extended, typos corrected, data
set expanded, figure added. To appear in Phys. Rev. D
|
Phys. Rev. D 104, 031501 (2021)
|
10.1103/PhysRevD.104.L031501
|
JLAB-THY-21-3318
|
hep-ph hep-ex nucl-ex nucl-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We present a Monte Carlo based analysis of the combined world data on
polarized lepton-nucleon deep-inelastic scattering at small Bjorken $x$ within
the polarized quark dipole formalism. We show for the first time that
double-spin asymmetries at $x<0.1$ can be successfully described using only
small-$x$ evolution derived from first-principles QCD, allowing predictions to
be made for the $g_1$ structure function at much smaller $x$. Anticipating
future data from the Electron-Ion Collider, we assess the impact of
electromagnetic and parity-violating polarization asymmetries on $g_1$ and
demonstrate an extraction of the individual flavor helicity PDFs at small $x$.
|
[
{
"created": "Thu, 11 Feb 2021 18:04:54 GMT",
"version": "v1"
},
{
"created": "Tue, 27 Jul 2021 21:37:52 GMT",
"version": "v2"
}
] |
2021-08-11
|
[
[
"Adamiak",
"Daniel",
""
],
[
"Kovchegov",
"Yuri V.",
""
],
[
"Melnitchouk",
"W.",
""
],
[
"Pitonyak",
"Daniel",
""
],
[
"Sato",
"Nobuo",
""
],
[
"Sievert",
"Matthew D.",
""
]
] |
We present a Monte Carlo based analysis of the combined world data on polarized lepton-nucleon deep-inelastic scattering at small Bjorken $x$ within the polarized quark dipole formalism. We show for the first time that double-spin asymmetries at $x<0.1$ can be successfully described using only small-$x$ evolution derived from first-principles QCD, allowing predictions to be made for the $g_1$ structure function at much smaller $x$. Anticipating future data from the Electron-Ion Collider, we assess the impact of electromagnetic and parity-violating polarization asymmetries on $g_1$ and demonstrate an extraction of the individual flavor helicity PDFs at small $x$.
|
1203.5557
|
John P. Ralston
|
John P. Ralston
|
Quantum Theory without Planck's Constant
|
42 pages, 9 figures
| null | null | null |
hep-ph physics.hist-ph quant-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Planck's constant was introduced as a fundamental scale in the early history
of quantum mechanics. We find a modern approach where Planck's constant is
absent: it is unobservable except as a constant of human convention. Despite
long reference to experiment, review shows that Planck's constant cannot be
obtained from the data of Ryberg, Davisson and Germer, Compton, or that used by
Planck himself. In the new approach Planck's constant is tied to macroscopic
conventions of Newtonian origin, which are dispensable. The precision of other
fundamental constants is substantially improved by eliminating Planck's
constant. The electron mass is determined about 67 times more precisely, and
the unit of electric charge determined 139 times more precisely. Improvement in
the experimental value of the fine structure constant allows new types of
experiment to be compared towards finding "new physics." The long-standing goal
of eliminating reliance on the artifact known as the International Prototype
Kilogram can be accomplished to assist progress in fundamental physics.
|
[
{
"created": "Sun, 25 Mar 2012 23:58:06 GMT",
"version": "v1"
}
] |
2012-03-27
|
[
[
"Ralston",
"John P.",
""
]
] |
Planck's constant was introduced as a fundamental scale in the early history of quantum mechanics. We find a modern approach where Planck's constant is absent: it is unobservable except as a constant of human convention. Despite long reference to experiment, review shows that Planck's constant cannot be obtained from the data of Ryberg, Davisson and Germer, Compton, or that used by Planck himself. In the new approach Planck's constant is tied to macroscopic conventions of Newtonian origin, which are dispensable. The precision of other fundamental constants is substantially improved by eliminating Planck's constant. The electron mass is determined about 67 times more precisely, and the unit of electric charge determined 139 times more precisely. Improvement in the experimental value of the fine structure constant allows new types of experiment to be compared towards finding "new physics." The long-standing goal of eliminating reliance on the artifact known as the International Prototype Kilogram can be accomplished to assist progress in fundamental physics.
|
1606.09576
|
Ma{\l}gorzata Janik
|
Ma{\l}gorzata Anna Janik and {\L}ukasz Kamil Graczykowski and Adam
Kisiel
|
Influence of quantum conservation laws on particle production in hadron
collisions
|
Quark Matter 2015 conference
| null |
10.1016/j.nuclphysa.2016.02.018
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Conservation laws strongly influence production of particles in high-energy
particle collisions. Effects connected to these mechanisms were studied in
details using correlation techniques in \ee\ collisions. At the time, models
were tuned to correctly reproduce the measurements. Similar studies for
hadron-hadron collisions have never been performed, until recent ALICE
measurements. ALICE has reported on studies of untriggered two-particle angular
correlations of identified particles ($\pi$, $K$, and p) measured in pp
collisions at center-of-mass energy of $\sqrt{s}=$ 7 TeV. Those preliminary
results confirm that also in hadron-hadron collisions, at much higher energies,
conservation laws strongly influence the shape of the correlation functions for
different particle types and must be taken into account while analysing the
data. Moreover, they show that the contemporary models (PYTHIA, PHOJET) no
longer reproduce the experimental data well.
|
[
{
"created": "Fri, 22 Jan 2016 14:20:38 GMT",
"version": "v1"
}
] |
2016-11-23
|
[
[
"Janik",
"Małgorzata Anna",
""
],
[
"Graczykowski",
"Łukasz Kamil",
""
],
[
"Kisiel",
"Adam",
""
]
] |
Conservation laws strongly influence production of particles in high-energy particle collisions. Effects connected to these mechanisms were studied in details using correlation techniques in \ee\ collisions. At the time, models were tuned to correctly reproduce the measurements. Similar studies for hadron-hadron collisions have never been performed, until recent ALICE measurements. ALICE has reported on studies of untriggered two-particle angular correlations of identified particles ($\pi$, $K$, and p) measured in pp collisions at center-of-mass energy of $\sqrt{s}=$ 7 TeV. Those preliminary results confirm that also in hadron-hadron collisions, at much higher energies, conservation laws strongly influence the shape of the correlation functions for different particle types and must be taken into account while analysing the data. Moreover, they show that the contemporary models (PYTHIA, PHOJET) no longer reproduce the experimental data well.
|
2104.05685
|
Van Que Tran
|
Mingxuan Du, Jinhan Liang, Zuowei Liu, Van Que Tran
|
A vector leptoquark interpretation of the muon $g-2$ and $B$ anomalies
|
6 pages, 3 figures
| null | null | null |
hep-ph
|
http://creativecommons.org/licenses/by/4.0/
|
We show that a single vector leptoquark can explain both the muon $g-2$
anomaly recently measured by the Muon g-2 experiment at Fermilab, and the
various $B$ decay anomalies, including the $R_{D^{(*)}}$ and $R_{K^{(*)}}$
anomalies which have been recently reported by the LHCb experiment. In order to
provide sizeable positive new physics contributions to the muon $g-2$, we
assume that the vector leptoquark particle couples to both left-handed and
right-handed fermions with equal strength. Our model is found to satisfy the
experimental constraints from the large hadron collider.
|
[
{
"created": "Mon, 12 Apr 2021 17:48:53 GMT",
"version": "v1"
}
] |
2021-04-13
|
[
[
"Du",
"Mingxuan",
""
],
[
"Liang",
"Jinhan",
""
],
[
"Liu",
"Zuowei",
""
],
[
"Tran",
"Van Que",
""
]
] |
We show that a single vector leptoquark can explain both the muon $g-2$ anomaly recently measured by the Muon g-2 experiment at Fermilab, and the various $B$ decay anomalies, including the $R_{D^{(*)}}$ and $R_{K^{(*)}}$ anomalies which have been recently reported by the LHCb experiment. In order to provide sizeable positive new physics contributions to the muon $g-2$, we assume that the vector leptoquark particle couples to both left-handed and right-handed fermions with equal strength. Our model is found to satisfy the experimental constraints from the large hadron collider.
|
0801.0360
|
Hank Miller
|
Justin M. Conroy, H. G. Miller
|
Color Superconductivity and Tsallis Statistics
| null |
Phys.Rev.D78:054010,2008
|
10.1103/PhysRevD.78.054010
| null |
hep-ph cond-mat.supr-con nucl-th
| null |
The generalized non-extensive statistics proposed by Tsallis have been
successfully utilized in many systems where long range interactions are
present. For high density quark matter an attractive long range interaction
arising from single gluon exchange suggests the formation of a diquark
condensate. We study the effects on this color superconducting phase for two
quark flavors due to a change to Tsallis statistics. By numerically solving the
gap equation we obtain a generalization of the universality condition,
$\frac{2\phi_{0}}{T_{C}}\approx 3.52$ and determine the temperature dependence
of the gap. For the Tsallis parameter $q\approx 1$ the specific heat is
exponential becoming more linear as q increases. This suggests that for larger
values of q s-wave color superconductors behave like high $T_c$ superconductors
rather than weak superconductors.
|
[
{
"created": "Wed, 2 Jan 2008 09:27:14 GMT",
"version": "v1"
}
] |
2009-01-09
|
[
[
"Conroy",
"Justin M.",
""
],
[
"Miller",
"H. G.",
""
]
] |
The generalized non-extensive statistics proposed by Tsallis have been successfully utilized in many systems where long range interactions are present. For high density quark matter an attractive long range interaction arising from single gluon exchange suggests the formation of a diquark condensate. We study the effects on this color superconducting phase for two quark flavors due to a change to Tsallis statistics. By numerically solving the gap equation we obtain a generalization of the universality condition, $\frac{2\phi_{0}}{T_{C}}\approx 3.52$ and determine the temperature dependence of the gap. For the Tsallis parameter $q\approx 1$ the specific heat is exponential becoming more linear as q increases. This suggests that for larger values of q s-wave color superconductors behave like high $T_c$ superconductors rather than weak superconductors.
|
1109.1508
|
Julian Heeck
|
Julian Heeck, Werner Rodejohann
|
Kinetic and mass mixing with three abelian groups
|
8 pages, references added, matches published version
|
Phys.Lett.B705:369-374,2011
|
10.1016/j.physletb.2011.10.050
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We present the possible mixing effects associated with the low-energy limit
of a Standard-Model extension by two abelian gauge groups U(1)_1 x U(1)_2. We
derive general formulae and approximate expressions that connect the gauge
eigenstates to the mass eigenstates. Applications using the well-studied groups
U(1)_B, U(1)_(B-L), U(1)_(L_alpha - L_beta) (L_alpha being lepton flavor
numbers), and U(1)_DM (a symmetry acting only on the dark matter sector) are
discussed briefly.
|
[
{
"created": "Wed, 7 Sep 2011 16:37:33 GMT",
"version": "v1"
},
{
"created": "Sat, 29 Oct 2011 07:36:07 GMT",
"version": "v2"
}
] |
2011-11-01
|
[
[
"Heeck",
"Julian",
""
],
[
"Rodejohann",
"Werner",
""
]
] |
We present the possible mixing effects associated with the low-energy limit of a Standard-Model extension by two abelian gauge groups U(1)_1 x U(1)_2. We derive general formulae and approximate expressions that connect the gauge eigenstates to the mass eigenstates. Applications using the well-studied groups U(1)_B, U(1)_(B-L), U(1)_(L_alpha - L_beta) (L_alpha being lepton flavor numbers), and U(1)_DM (a symmetry acting only on the dark matter sector) are discussed briefly.
|
2404.18996
|
Subrata Samanta
|
Debtosh Chowdhury, Poulami Mondal, Subrata Samanta
|
Next-to-Leading Order Unitarity Fits in the Extended Georgi-Machacek
Model
|
58 pages, 13 figures. Comments are welcome
| null | null | null |
hep-ph hep-ex
|
http://creativecommons.org/licenses/by/4.0/
|
Minimal triplet scalar extension of the Standard Model demanding custodial
symmetry gives rise to the extended Georgi-Machacek (eGM) model. We compute
one-loop corrections to all $2 \rightarrow 2$ bosonic scattering amplitudes in
the eGM model, and place next-to-leading order (NLO) unitarity bounds on the
quartic couplings. Additionally, we derive state-of-the-art constraints on the
quartic couplings demanding the stability of the scalar potential. We perform a
global fit of the eGM model to these theoretical bounds and to the latest Higgs
signal strength results from the LHC detectors. In addition to the custodial
symmetry, imposing a global $SU(2)_L\otimes SU(2)_R$ symmetry on the scalar
potential at the electroweak scale results in the well-known Georgi-Machacek
(GM) model. We assess the impact of the state-of-the-art theoretical
constraints on the fit to the Higgs signal strength data in the GM model, with
particular emphasis on the NLO unitarity bounds. We observe that the global fit
disfavors the region where $\kappa_V$ is greater than $1.05$ with a 95.4\%
confidence level. We obtain an upper limit on the absolute values of the
quartic couplings to be 1.9 (4.2) and see that the absolute mass differences
between the heavy Higgs bosons cannot exceed 400 GeV (380 GeV) in the GM (eGM)
model. Finally, we find that the maximal mass splitting within the members of
custodial symmetric multiplets is restricted to be smaller than 210 GeV in the
eGM model.
|
[
{
"created": "Mon, 29 Apr 2024 18:00:01 GMT",
"version": "v1"
}
] |
2024-05-01
|
[
[
"Chowdhury",
"Debtosh",
""
],
[
"Mondal",
"Poulami",
""
],
[
"Samanta",
"Subrata",
""
]
] |
Minimal triplet scalar extension of the Standard Model demanding custodial symmetry gives rise to the extended Georgi-Machacek (eGM) model. We compute one-loop corrections to all $2 \rightarrow 2$ bosonic scattering amplitudes in the eGM model, and place next-to-leading order (NLO) unitarity bounds on the quartic couplings. Additionally, we derive state-of-the-art constraints on the quartic couplings demanding the stability of the scalar potential. We perform a global fit of the eGM model to these theoretical bounds and to the latest Higgs signal strength results from the LHC detectors. In addition to the custodial symmetry, imposing a global $SU(2)_L\otimes SU(2)_R$ symmetry on the scalar potential at the electroweak scale results in the well-known Georgi-Machacek (GM) model. We assess the impact of the state-of-the-art theoretical constraints on the fit to the Higgs signal strength data in the GM model, with particular emphasis on the NLO unitarity bounds. We observe that the global fit disfavors the region where $\kappa_V$ is greater than $1.05$ with a 95.4\% confidence level. We obtain an upper limit on the absolute values of the quartic couplings to be 1.9 (4.2) and see that the absolute mass differences between the heavy Higgs bosons cannot exceed 400 GeV (380 GeV) in the GM (eGM) model. Finally, we find that the maximal mass splitting within the members of custodial symmetric multiplets is restricted to be smaller than 210 GeV in the eGM model.
|
0709.4259
|
Jing Shao
|
Gordon L. Kane, Piyush Kumar and Jing Shao
|
Unravelling Strings at the LHC
|
34 pages, 16 figures
|
Phys.Rev.D77:116005,2008
|
10.1103/PhysRevD.77.116005
| null |
hep-ph hep-ex hep-th
| null |
We construct LHC signature footprints for four semi-realistic string/$M$
theory vacua with an MSSM visible sector. We find that they all give rise to
limited regions in LHC signature space, and are qualitatively different from
each other for understandable reasons. We also propose a technique in which
correlations of LHC signatures can be effectively used to distinguish among
these string theory vacua. We expect the technique to be useful for more
general string vacua. We argue that further systematic analysis with this
approach will allow LHC data to disfavor or exclude major ``corners'' of
string/$M$ theory and favor others. The technique can be used with limited
integrated luminosity and improved.
|
[
{
"created": "Wed, 26 Sep 2007 20:34:09 GMT",
"version": "v1"
}
] |
2008-06-18
|
[
[
"Kane",
"Gordon L.",
""
],
[
"Kumar",
"Piyush",
""
],
[
"Shao",
"Jing",
""
]
] |
We construct LHC signature footprints for four semi-realistic string/$M$ theory vacua with an MSSM visible sector. We find that they all give rise to limited regions in LHC signature space, and are qualitatively different from each other for understandable reasons. We also propose a technique in which correlations of LHC signatures can be effectively used to distinguish among these string theory vacua. We expect the technique to be useful for more general string vacua. We argue that further systematic analysis with this approach will allow LHC data to disfavor or exclude major ``corners'' of string/$M$ theory and favor others. The technique can be used with limited integrated luminosity and improved.
|
hep-ph/0103320
|
Shaaban Khalil
|
S. Abel, S. Khalil, and O. Lebedev
|
EDM Constraints in Supersymmetric Theories
|
34 pages, 18 figures, to appear in Nucl. Phys. B
|
Nucl.Phys.B606:151-182,2001
|
10.1016/S0550-3213(01)00233-4
|
SUSX-TH/01-016
|
hep-ph
| null |
We systematically analyze constraints on supersymmetric theories imposed by
the experimental bounds on the electron, neutron, and mercury electric dipole
moments. We critically reappraise the known mechanisms to suppress the EDMs and
conclude that only the scenarios with approximate CP-symmetry or
flavour-off-diagonal CP violation remain attractive after the addition of the
mercury EDM constraint.
|
[
{
"created": "Thu, 29 Mar 2001 14:34:15 GMT",
"version": "v1"
},
{
"created": "Mon, 14 May 2001 11:36:17 GMT",
"version": "v2"
}
] |
2010-05-28
|
[
[
"Abel",
"S.",
""
],
[
"Khalil",
"S.",
""
],
[
"Lebedev",
"O.",
""
]
] |
We systematically analyze constraints on supersymmetric theories imposed by the experimental bounds on the electron, neutron, and mercury electric dipole moments. We critically reappraise the known mechanisms to suppress the EDMs and conclude that only the scenarios with approximate CP-symmetry or flavour-off-diagonal CP violation remain attractive after the addition of the mercury EDM constraint.
|
hep-ph/9812420
|
Michel C. Vetterli
|
Michel C. Vetterli (TRIUMF)
|
The Spin Structure of the Nucleon (Lectures at the 13th Lake Louise
Winter Institute)
|
51 pages, 24 figures, Latex, psfigure.sty, rotating.sty, sprocl.sty
| null | null | null |
hep-ph
| null |
This paper gives a pedagogical introduction to our knowledge of the spin
structure of the nucleon. In particular, polarised deep inelastic lepton
scattering is presented as a tool to study how the nucleon's constituents
combine to generate its spin. The importance of semi-inclusive measurements is
discussed and a window on future experiments in the field is given.
|
[
{
"created": "Thu, 17 Dec 1998 20:24:09 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Vetterli",
"Michel C.",
"",
"TRIUMF"
]
] |
This paper gives a pedagogical introduction to our knowledge of the spin structure of the nucleon. In particular, polarised deep inelastic lepton scattering is presented as a tool to study how the nucleon's constituents combine to generate its spin. The importance of semi-inclusive measurements is discussed and a window on future experiments in the field is given.
|
0803.4176
|
Carl Albright
|
Carl H. Albright
|
Differentiating Neutrino Models on the Basis of $\theta_{13}$ and Lepton
Flavor Violation
|
10 pages, 7 figures, to appear in Proceedings of the International
Workshop on Grand Unified Theories: Current Status and Future Prospects
(GUT07), December 17-19, 2007, Kusatsu, Japan
|
AIP Conf.Proc.1015:42-51,2008
|
10.1063/1.2939060
|
FERMILAB-CONF-08-050-T
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We show how models of neutrino masses and mixings can be differentiated on
the basis of their predictions for $\theta_{13}$ and lepton flavor violation in
radiative charged lepton decays and $\mu - e$ conversion. We illustrate the
lepton flavor violation results for five predictive SO(10) SUSY GUT models and
point out the relative importance of their heavy right-handed neutrino mass
spectra and $\theta_{13}$ predictions.
|
[
{
"created": "Fri, 28 Mar 2008 19:05:08 GMT",
"version": "v1"
}
] |
2009-03-09
|
[
[
"Albright",
"Carl H.",
""
]
] |
We show how models of neutrino masses and mixings can be differentiated on the basis of their predictions for $\theta_{13}$ and lepton flavor violation in radiative charged lepton decays and $\mu - e$ conversion. We illustrate the lepton flavor violation results for five predictive SO(10) SUSY GUT models and point out the relative importance of their heavy right-handed neutrino mass spectra and $\theta_{13}$ predictions.
|
1804.10017
|
Stefano Frixione
|
R. Frederix, S. Frixione, V. Hirschi, D. Pagani, H.-S. Shao, M. Zaro
|
The automation of next-to-leading order electroweak calculations
|
121 pages, 16 figures; this version is identical to the JHEP one,
including the erratum to the latter
| null |
10.1007/JHEP07(2018)185
|
Nikhef/2018-015, TUM-HEP-1138/18
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We present the key features relevant to the automated computation of all the
leading- and next-to-leading order contributions to short-distance cross
sections in a mixed-coupling expansion, with special emphasis on the first
subleading NLO term in the QCD+EW scenario, commonly referred to as NLO EW
corrections. We discuss, in particular, the FKS subtraction in the context of a
mixed-coupling expansion; the extension of the FKS subtraction to processes
that include final-state tagged particles, defined by means of fragmentation
functions; and some properties of the complex mass scheme. We combine the
present paper with the release of a new version of MadGraph5_aMC@NLO, capable
of dealing with mixed-coupling expansions. We use the code to obtain
illustrative inclusive and differential results for the 13-TeV LHC.
|
[
{
"created": "Thu, 26 Apr 2018 12:31:08 GMT",
"version": "v1"
},
{
"created": "Thu, 21 Oct 2021 12:48:15 GMT",
"version": "v2"
}
] |
2021-10-22
|
[
[
"Frederix",
"R.",
""
],
[
"Frixione",
"S.",
""
],
[
"Hirschi",
"V.",
""
],
[
"Pagani",
"D.",
""
],
[
"Shao",
"H. -S.",
""
],
[
"Zaro",
"M.",
""
]
] |
We present the key features relevant to the automated computation of all the leading- and next-to-leading order contributions to short-distance cross sections in a mixed-coupling expansion, with special emphasis on the first subleading NLO term in the QCD+EW scenario, commonly referred to as NLO EW corrections. We discuss, in particular, the FKS subtraction in the context of a mixed-coupling expansion; the extension of the FKS subtraction to processes that include final-state tagged particles, defined by means of fragmentation functions; and some properties of the complex mass scheme. We combine the present paper with the release of a new version of MadGraph5_aMC@NLO, capable of dealing with mixed-coupling expansions. We use the code to obtain illustrative inclusive and differential results for the 13-TeV LHC.
|
hep-ph/9908500
|
Thomas Gehrmann
|
T.Gehrmann (TTP, Karlsruhe)
|
Summary: Spin Physics
|
LaTeX, 13 pages, Summary talk presented at the Workshop ``Polarized
Protons at High Energies - Accelerator Challenges and Physics
Opportunities'', DESY Hamburg, 17-20 May, 1999; The complete paper, including
figures, is also available via anonymous ftp at
ftp://ttpux2.physik.uni-karlsruhe.de/ttp99/ttp99-36/ or via www at
http://www-ttp.physik.uni-karlsruhe.de/Preprints/
| null | null |
TTP99-36
|
hep-ph
| null |
The spin physics parallel sessions at this workshop made a critical review of
the physics potential of future experiments on polarized nucleons, with an
emphasis on the potential impact of polarized electron-proton collisions at
HERA. A summary of the results and discussions from these sessions is presented
in this article.
|
[
{
"created": "Mon, 30 Aug 1999 09:06:22 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Gehrmann",
"T.",
"",
"TTP, Karlsruhe"
]
] |
The spin physics parallel sessions at this workshop made a critical review of the physics potential of future experiments on polarized nucleons, with an emphasis on the potential impact of polarized electron-proton collisions at HERA. A summary of the results and discussions from these sessions is presented in this article.
|
hep-ph/0408144
|
Kim Maltman
|
Kim Maltman
|
Quark Model Perspectives on Pentaquark Exotics
|
12 pages, Invited Talk, Workshop on the Physics of Excited Nucleons
(NSTAR 2004), Grenoble, France, March 24-27, 2004
| null |
10.1142/9789812702272_0005
|
YU-PP-I/E-KM-04-1
|
hep-ph
| null |
Expectations and predictions for pentaquark exotics based on the quark model
perspective are presented. Recent quark model scenarios, and calculations
performed in different realizations of the quark model approach, up to the end
of March 2004, are also reviewed and discussed.
|
[
{
"created": "Wed, 11 Aug 2004 22:03:31 GMT",
"version": "v1"
}
] |
2017-08-23
|
[
[
"Maltman",
"Kim",
""
]
] |
Expectations and predictions for pentaquark exotics based on the quark model perspective are presented. Recent quark model scenarios, and calculations performed in different realizations of the quark model approach, up to the end of March 2004, are also reviewed and discussed.
|
1109.4846
|
Yue-Liang Wu
|
Da Huang, Yong Tang, Yue-Liang Wu
|
Note on Higgs Decay into Two Photons $H\to \gamma\gamma$
|
13 pages, 2 figures, references added, advantage of loop
regularization method with the concept of irreduciable loop integral is
emphasized, published version
|
Commun.Theor.Phys. 57 (2012) 427-434
|
10.1088/0253-6102/57/3/14
| null |
hep-ph hep-ex
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The Higgs decay $H\to \gamma\gamma$ duo to the virtual $W$-loop effect is
revisited in the unitary gauge by using the symmetry-preserving and
divergent-behavior-preserving loop regularization method, which is realized in
the four dimensional space-time without changing original theory. Though the
one-loop amplitude of $H\to \gamma\gamma$ is finite as the Higgs boson in the
standard model has no direct interaction with the massless photons at tree
level, while it involves both tensor-type and scalar-type divergent integrals
which can in general destroy the gauge invariance without imposing a proper
regularization scheme to make them well-defined. As the loop regularization
scheme can ensure the consistency conditions between the regularized
tensor-type and scalar-type divergent irreducible loop integrals to preserve
gauge invariance, we explicitly show the absence of decoupling in the limit
$M_W/M_H\to0$ and obtain a result agreed exactly with the earlier one in the
literature. We then clarify the discrepancy between the earlier result and the
recent one obtained by R. Gastmans, S.L. Wu and T.T. Wu. The advantage of
calculation in the unitary gauge becomes manifest that the non-decoupling
arises from the longitudinal contribution of the $W$ gauge boson.
|
[
{
"created": "Thu, 22 Sep 2011 15:14:17 GMT",
"version": "v1"
},
{
"created": "Wed, 18 Jan 2012 12:33:21 GMT",
"version": "v2"
}
] |
2012-04-12
|
[
[
"Huang",
"Da",
""
],
[
"Tang",
"Yong",
""
],
[
"Wu",
"Yue-Liang",
""
]
] |
The Higgs decay $H\to \gamma\gamma$ duo to the virtual $W$-loop effect is revisited in the unitary gauge by using the symmetry-preserving and divergent-behavior-preserving loop regularization method, which is realized in the four dimensional space-time without changing original theory. Though the one-loop amplitude of $H\to \gamma\gamma$ is finite as the Higgs boson in the standard model has no direct interaction with the massless photons at tree level, while it involves both tensor-type and scalar-type divergent integrals which can in general destroy the gauge invariance without imposing a proper regularization scheme to make them well-defined. As the loop regularization scheme can ensure the consistency conditions between the regularized tensor-type and scalar-type divergent irreducible loop integrals to preserve gauge invariance, we explicitly show the absence of decoupling in the limit $M_W/M_H\to0$ and obtain a result agreed exactly with the earlier one in the literature. We then clarify the discrepancy between the earlier result and the recent one obtained by R. Gastmans, S.L. Wu and T.T. Wu. The advantage of calculation in the unitary gauge becomes manifest that the non-decoupling arises from the longitudinal contribution of the $W$ gauge boson.
|
1710.08086
|
Riley Patrick
|
Riley Patrick, Pankaj Sharma and Anthony G. Williams
|
Triple top signal as a probe of charged Higgs in a 2HDM
|
5 pages, 5 figures, 2 tables
| null |
10.1016/j.physletb.2018.03.033
|
ADP-17-34/T1040
|
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Within the framework of the type-II Two Higgs Doublet Model (2HDM-II) we
study the production of three top quarks at the Large Hadron Collider (LHC). In
the Standard Model the production cross section of three tops is low ($\approx
3$fb), while it is expected to be significant in the 2HDM-II for reasonable
choices of the parameters. We study the production of a charged Higgs in
association with a top quark, followed by the decays $H^{\pm} \to W^{\pm}A$ and
$A \to t\bar{t}$. We undertake a full detector simulation of the signal, and
use simple conservative cuts, focusing on the final states that contain three
or more leptons, and exactly one same sign di-lepton pair. Finally, we present
the exclusion bounds dependent on charged Higgs and pseudoscalar Higgs masses
expected in the near future at the 14TeV LHC.
|
[
{
"created": "Mon, 23 Oct 2017 04:58:22 GMT",
"version": "v1"
}
] |
2018-03-16
|
[
[
"Patrick",
"Riley",
""
],
[
"Sharma",
"Pankaj",
""
],
[
"Williams",
"Anthony G.",
""
]
] |
Within the framework of the type-II Two Higgs Doublet Model (2HDM-II) we study the production of three top quarks at the Large Hadron Collider (LHC). In the Standard Model the production cross section of three tops is low ($\approx 3$fb), while it is expected to be significant in the 2HDM-II for reasonable choices of the parameters. We study the production of a charged Higgs in association with a top quark, followed by the decays $H^{\pm} \to W^{\pm}A$ and $A \to t\bar{t}$. We undertake a full detector simulation of the signal, and use simple conservative cuts, focusing on the final states that contain three or more leptons, and exactly one same sign di-lepton pair. Finally, we present the exclusion bounds dependent on charged Higgs and pseudoscalar Higgs masses expected in the near future at the 14TeV LHC.
|
1810.09886
|
Leonid Glozman
|
L. Ya. Glozman
|
Chiralspin symmetry and its implications for QCD
|
11 pages; Talk given at 7th International Conference on New Frontiers
in Physics (ICNFP 2018), Crete, 4-12 July 2018; Symposium "Quantum
Chromodynamics and its Symmetries", Oberwoelz, Austria, 9-15 September 2018;
final version; to appear in Universe
| null | null | null |
hep-ph hep-lat hep-th nucl-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
In a local gauge-invariant theory with massless Dirac fermions a symmetry of
the Lorentz-invariant fermion charge is larger than a symmetry of the
Lagrangian as a whole. While the Dirac Lagrangian exhibits only a chiral
symmetry, the fermion charge operator is invariant under a larger symmetry
group, SU(2N_F), that includes chiral transformations as well as SU(2)_{CS}
chiralspin transformations that mix the right- and left-handed components of
fermions. Consequently a symmetry of the electric interaction, that is driven
by the charge density, is larger than a symmetry of the magnetic interaction
and of the kinetic term. This allows to separate in some situations electric
and magnetic contributions. In particutar, in QCD the chromo-magnetic
interaction contributes only to the near-zero modes of the Dirac operator,
while confining chromo-electric interaction contributes to all modes. At high
temperatures, above the chiral restoration crossover, QCD exhibits approximate
SU(2)_{CS} and SU(2N_F) symmetries that are incompatible with free deconfined
quarks. Consequently elementary objects in QCD in this regime are quarks with a
definite chirality bound by the chromo-electric field, without the
chromo-magnetic effects. In this regime QCD can be described as a stringy
fluid.
|
[
{
"created": "Tue, 23 Oct 2018 14:39:39 GMT",
"version": "v1"
},
{
"created": "Thu, 1 Nov 2018 15:54:13 GMT",
"version": "v2"
},
{
"created": "Fri, 11 Jan 2019 14:14:51 GMT",
"version": "v3"
}
] |
2019-01-14
|
[
[
"Glozman",
"L. Ya.",
""
]
] |
In a local gauge-invariant theory with massless Dirac fermions a symmetry of the Lorentz-invariant fermion charge is larger than a symmetry of the Lagrangian as a whole. While the Dirac Lagrangian exhibits only a chiral symmetry, the fermion charge operator is invariant under a larger symmetry group, SU(2N_F), that includes chiral transformations as well as SU(2)_{CS} chiralspin transformations that mix the right- and left-handed components of fermions. Consequently a symmetry of the electric interaction, that is driven by the charge density, is larger than a symmetry of the magnetic interaction and of the kinetic term. This allows to separate in some situations electric and magnetic contributions. In particutar, in QCD the chromo-magnetic interaction contributes only to the near-zero modes of the Dirac operator, while confining chromo-electric interaction contributes to all modes. At high temperatures, above the chiral restoration crossover, QCD exhibits approximate SU(2)_{CS} and SU(2N_F) symmetries that are incompatible with free deconfined quarks. Consequently elementary objects in QCD in this regime are quarks with a definite chirality bound by the chromo-electric field, without the chromo-magnetic effects. In this regime QCD can be described as a stringy fluid.
|
hep-ph/0307003
|
George Rupp
|
M. D. Scadron, G. Rupp, E. van Beveren, and F. Kleefeld
|
SU(3) Mass Splittings for $\bar{q}q$ Mesons and $qqq$ Baryons
|
8 Pages, AIP Proc. Style; Contribution to the High-Energy Physics
Workshop "Scalar Mesons: an Interesting Puzzle for QCD", May 16-18, 2003,
SUNY Institute of Technology, Utica (NY)
|
AIPConf.Proc.688:183-190,2003
|
10.1063/1.1632205
| null |
hep-ph
| null |
By comparing SU(3)-breaking scales of linear mass formulae, it is shown that
the lowest vector, axial-vector, and scalar mesons all have a $\bar{q}q$
configuration, while the ground-state octet and decuplet baryons are $qqq$.
Also, the quark-level linear $\sigma$ model is employed to predict similar
$\bar{q}q$ and $qqq$ states. Finally, the approximate mass degeneracy of the
scalar $a_0$(980) and $f_0$(980) mesons is demonstrated to be accidental.
|
[
{
"created": "Mon, 30 Jun 2003 21:31:08 GMT",
"version": "v1"
}
] |
2008-11-26
|
[
[
"Scadron",
"M. D.",
""
],
[
"Rupp",
"G.",
""
],
[
"van Beveren",
"E.",
""
],
[
"Kleefeld",
"F.",
""
]
] |
By comparing SU(3)-breaking scales of linear mass formulae, it is shown that the lowest vector, axial-vector, and scalar mesons all have a $\bar{q}q$ configuration, while the ground-state octet and decuplet baryons are $qqq$. Also, the quark-level linear $\sigma$ model is employed to predict similar $\bar{q}q$ and $qqq$ states. Finally, the approximate mass degeneracy of the scalar $a_0$(980) and $f_0$(980) mesons is demonstrated to be accidental.
|
2403.11862
|
Parham Dehghani
|
Parham Dehghani, Mariana Frank, Benjamin Fuks
|
Collider imprint of vector-like leptons in light of anomalous magnetic
moment and neutrino data
|
9 figures, 6 tables
| null | null | null |
hep-ph
|
http://creativecommons.org/licenses/by/4.0/
|
We investigate the impact of incorporating anomaly-free representations of
vector-like leptons into the Standard Model, aiming to address longstanding
puzzles related to the anomalous magnetic moments of the muon and electron
while maintaining consistency with neutrino masses and mixings. We find that
among the various representations of vector-like leptons permitted by the
Standard Model gauge symmetry, only weak doublets and singlets offer
satisfactory solutions, all associated with a significantly constrained
parameter space. Our analysis delves into the associated parameter space,
identifying representative benchmark scenarios suitable for collider studies.
These setups yield a distinctive six-lepton signature whose associated signals
can easily be distinguished from the Standard Model background, providing a
clear signal indicative of new physics models featuring vector-like leptons.
Our work hence sheds light on the potential implications of vector-like leptons
in resolving discrepancies inherent to the Standard Model, while also offering
insights into experimental avenues for further exploration.
|
[
{
"created": "Mon, 18 Mar 2024 15:15:29 GMT",
"version": "v1"
}
] |
2024-03-19
|
[
[
"Dehghani",
"Parham",
""
],
[
"Frank",
"Mariana",
""
],
[
"Fuks",
"Benjamin",
""
]
] |
We investigate the impact of incorporating anomaly-free representations of vector-like leptons into the Standard Model, aiming to address longstanding puzzles related to the anomalous magnetic moments of the muon and electron while maintaining consistency with neutrino masses and mixings. We find that among the various representations of vector-like leptons permitted by the Standard Model gauge symmetry, only weak doublets and singlets offer satisfactory solutions, all associated with a significantly constrained parameter space. Our analysis delves into the associated parameter space, identifying representative benchmark scenarios suitable for collider studies. These setups yield a distinctive six-lepton signature whose associated signals can easily be distinguished from the Standard Model background, providing a clear signal indicative of new physics models featuring vector-like leptons. Our work hence sheds light on the potential implications of vector-like leptons in resolving discrepancies inherent to the Standard Model, while also offering insights into experimental avenues for further exploration.
|
1809.07474
|
Subhaditya Bhattacharya
|
Subhaditya Bhattacharya, Purusottam Ghosh, Narendra Sahu
|
Multipartite Dark Matter with Scalars, Fermions and signatures at LHC
|
A section discussing the possible connection to inflation is added.
The version is published in JHEP
|
JHEP02(2019)059
|
10.1007/JHEP02(2019)059
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Basic idea of this analysis is to achieve a two-component dark matter (DM)
framework composed of a scalar and a fermion, with non-negligible DM-DM
interaction contributing to thermal freeze out (hence relic density), but
hiding them from direct detection bounds. We therefore augment the Standard
Model (SM) with a scalar singlet ($S$) and three vectorlike fermions: two
singlets ($\chi_1,\chi_2$) and a doublet ($N$). Stability of the two DM
components is achieved by a discrete $\mathcal{Z}_2 \times
{\mathcal{Z}^\prime}_2$ symmetry, under which the additional fields transform
suitably. Fermion fields having same $\mathcal{Z}_2 \times
{\mathcal{Z}^\prime}_2$ charge ($N,\chi_1$ in the model) mix after electroweak
symmetry breaking (EWSB) and the lightest component becomes one of the DM
candidates, while scalar singlet $S$ is the other DM component connected to
visible sector by Higgs portal coupling. The heavy fermion ($\chi_2$) plays the
role of mediator to connect the two DM candidates through Yukawa interaction.
This opens up a large parameter space for the heavier DM component through
DM-DM conversion. Hadronically quiet dilepton signature, arising from the
fermion dark sector, can be observed at Large Hadron Collider (LHC) aided by
the presence of a lighter scalar DM component, satisfying relic density and
direct search bounds through DM-DM conversion.
|
[
{
"created": "Thu, 20 Sep 2018 04:39:30 GMT",
"version": "v1"
},
{
"created": "Tue, 19 Feb 2019 11:58:56 GMT",
"version": "v2"
}
] |
2019-02-20
|
[
[
"Bhattacharya",
"Subhaditya",
""
],
[
"Ghosh",
"Purusottam",
""
],
[
"Sahu",
"Narendra",
""
]
] |
Basic idea of this analysis is to achieve a two-component dark matter (DM) framework composed of a scalar and a fermion, with non-negligible DM-DM interaction contributing to thermal freeze out (hence relic density), but hiding them from direct detection bounds. We therefore augment the Standard Model (SM) with a scalar singlet ($S$) and three vectorlike fermions: two singlets ($\chi_1,\chi_2$) and a doublet ($N$). Stability of the two DM components is achieved by a discrete $\mathcal{Z}_2 \times {\mathcal{Z}^\prime}_2$ symmetry, under which the additional fields transform suitably. Fermion fields having same $\mathcal{Z}_2 \times {\mathcal{Z}^\prime}_2$ charge ($N,\chi_1$ in the model) mix after electroweak symmetry breaking (EWSB) and the lightest component becomes one of the DM candidates, while scalar singlet $S$ is the other DM component connected to visible sector by Higgs portal coupling. The heavy fermion ($\chi_2$) plays the role of mediator to connect the two DM candidates through Yukawa interaction. This opens up a large parameter space for the heavier DM component through DM-DM conversion. Hadronically quiet dilepton signature, arising from the fermion dark sector, can be observed at Large Hadron Collider (LHC) aided by the presence of a lighter scalar DM component, satisfying relic density and direct search bounds through DM-DM conversion.
|
1812.08189
|
Markus Ebert
|
Markus A. Ebert, Ian Moult, Iain W. Stewart, Frank J. Tackmann,
Gherardo Vita, and Hua Xing Zhu
|
Subleading Power Rapidity Divergences and Power Corrections for $q_T$
|
40 pages + appendices, 3 figures; v2: TMD collaboration included in
acknowledgement; v3: minor changes, journal version
|
JHEP04(2019)123
|
10.1007/JHEP04(2019)123
|
MIT-CTP 5087, DESY 18-207
|
hep-ph nucl-th
|
http://creativecommons.org/licenses/by/4.0/
|
A number of important observables exhibit logarithms in their perturbative
description that are induced by emissions at widely separated rapidities. These
include transverse-momentum ($q_T$) logarithms, logarithms involving
heavy-quark or electroweak gauge boson masses, and small-$x$ logarithms. In
this paper, we initiate the study of rapidity logarithms, and the associated
rapidity divergences, at subleading order in the power expansion. This is
accomplished using the soft collinear effective theory (SCET). We discuss the
structure of subleading-power rapidity divergences and how to consistently
regulate them. We introduce a new pure rapidity regulator and a corresponding
$\overline{\rm MS}$-like scheme, which handles rapidity divergences while
maintaining the homogeneity of the power expansion. We find that power-law
rapidity divergences appear at subleading power, which give rise to derivatives
of parton distribution functions. As a concrete example, we consider the $q_T$
spectrum for color-singlet production, for which we compute the complete
$q_T^2/Q^2$ suppressed power corrections at $\mathcal{O}(\alpha_s)$, including
both logarithmic and nonlogarithmic terms. Our results also represent an
important first step towards carrying out a resummation of subleading-power
rapidity logarithms.
|
[
{
"created": "Wed, 19 Dec 2018 19:00:27 GMT",
"version": "v1"
},
{
"created": "Mon, 14 Jan 2019 22:20:46 GMT",
"version": "v2"
},
{
"created": "Tue, 23 Apr 2019 15:23:17 GMT",
"version": "v3"
}
] |
2019-04-24
|
[
[
"Ebert",
"Markus A.",
""
],
[
"Moult",
"Ian",
""
],
[
"Stewart",
"Iain W.",
""
],
[
"Tackmann",
"Frank J.",
""
],
[
"Vita",
"Gherardo",
""
],
[
"Zhu",
"Hua Xing",
""
]
] |
A number of important observables exhibit logarithms in their perturbative description that are induced by emissions at widely separated rapidities. These include transverse-momentum ($q_T$) logarithms, logarithms involving heavy-quark or electroweak gauge boson masses, and small-$x$ logarithms. In this paper, we initiate the study of rapidity logarithms, and the associated rapidity divergences, at subleading order in the power expansion. This is accomplished using the soft collinear effective theory (SCET). We discuss the structure of subleading-power rapidity divergences and how to consistently regulate them. We introduce a new pure rapidity regulator and a corresponding $\overline{\rm MS}$-like scheme, which handles rapidity divergences while maintaining the homogeneity of the power expansion. We find that power-law rapidity divergences appear at subleading power, which give rise to derivatives of parton distribution functions. As a concrete example, we consider the $q_T$ spectrum for color-singlet production, for which we compute the complete $q_T^2/Q^2$ suppressed power corrections at $\mathcal{O}(\alpha_s)$, including both logarithmic and nonlogarithmic terms. Our results also represent an important first step towards carrying out a resummation of subleading-power rapidity logarithms.
|
2403.08021
|
Tzihu\'e Cisneros P\'erez
|
T. Cisneros-P\'erez, M. A. Hern\'andez-Ru\'iz, A. Ramirez-Morales, A.
Guti\'errez-Rodr\'iguez, and J. Monta\~no-Dom\'inguez
|
Top anomalous chromomagnetic dipole moment in the Bestest Little Higgs
Model
| null | null | null | null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We investigate the anomalous Chromomagnetic Dipole Moment (CMDM),
$\hat{\mu}^{BLHM}_t$ of the top quark in the Bestest Little Higgs Model (BLHM).
We include new interactions with the involvement of the extended CKM matrix of
the BLHM and we explore most of the allowed parameter space, obtaining multiple
CMDM in the range of $10^{-4}-10^{-2}$. We consider experimental and model
parameter uncertainties to integrate them into all our calculations using a
Monte Carlo method. This enables us to determine the extent to which deviations
arising from experimental errors can be accommodated within the statistical
errors of the model and which relate to the physics framework of the BLHM,
guiding future theory, phenomenological, and experimental research.
|
[
{
"created": "Tue, 12 Mar 2024 18:38:29 GMT",
"version": "v1"
}
] |
2024-03-14
|
[
[
"Cisneros-Pérez",
"T.",
""
],
[
"Hernández-Ruíz",
"M. A.",
""
],
[
"Ramirez-Morales",
"A.",
""
],
[
"Gutiérrez-Rodríguez",
"A.",
""
],
[
"Montaño-Domínguez",
"J.",
""
]
] |
We investigate the anomalous Chromomagnetic Dipole Moment (CMDM), $\hat{\mu}^{BLHM}_t$ of the top quark in the Bestest Little Higgs Model (BLHM). We include new interactions with the involvement of the extended CKM matrix of the BLHM and we explore most of the allowed parameter space, obtaining multiple CMDM in the range of $10^{-4}-10^{-2}$. We consider experimental and model parameter uncertainties to integrate them into all our calculations using a Monte Carlo method. This enables us to determine the extent to which deviations arising from experimental errors can be accommodated within the statistical errors of the model and which relate to the physics framework of the BLHM, guiding future theory, phenomenological, and experimental research.
|
hep-ph/9909385
|
A. J. Buchmann
|
A. J. Buchmann
|
N->Delta Quadrupole Transition in the Constituent Quark Model
|
12 pages, published in the Proceedings of the 8th International
Conference on the Structure of Baryons, Bonn, Germany, Sept. 22-26, 1998,
Baryons' 98, eds. D. W. Menze and B. Ch. Metsch, World Scientific, Singapore,
1999, pg. 731
| null | null | null |
hep-ph nucl-th
| null |
Information on the intrinsic deformation of the proton can be obtained by
studying the electromagnetic p-->Delta+ quadrupole transition. Recent
experiments have shown that the electric quadrupole (E2) strength in gamma p
--> Delta+ is about 10 times larger than predicted by the simple quark model
using only one-body currents. Our analysis provides evidence for the dominance
of exchange currents in the N-->Delta quadrupole transition and identifies the
physical mechanism leading to the observed E2 strength.
|
[
{
"created": "Wed, 15 Sep 1999 16:22:22 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Buchmann",
"A. J.",
""
]
] |
Information on the intrinsic deformation of the proton can be obtained by studying the electromagnetic p-->Delta+ quadrupole transition. Recent experiments have shown that the electric quadrupole (E2) strength in gamma p --> Delta+ is about 10 times larger than predicted by the simple quark model using only one-body currents. Our analysis provides evidence for the dominance of exchange currents in the N-->Delta quadrupole transition and identifies the physical mechanism leading to the observed E2 strength.
|
2001.08093
|
Pablo G. Ortega
|
Pablo G. Ortega, Jorge Segovia, David R. Entem and Francisco Fernandez
|
Spectroscopy of $\mathbf{B_c}$ mesons and the possibility of finding
exotic $\mathbf{B_c}$-like structures
|
7 pages, 4 tables
| null |
10.1140/epjc/s10052-020-7764-6
| null |
hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The bottom-charmed ($B_c$) mesons are more stable than their charmonium
($c\bar c$) and bottomium ($b\bar b$) partners because they cannot annihilate
into gluons. However, the low production cross-sections and
signal-to-background ratios avoided until now their clear identification. The
recent experimental results reported by CMS and LHCb at CERN open the
possibility of having a $B_c$ spectrum as complete as the ones of charmonium
and bottomonium. Motivated by this expectation, we compute bottom-charmed meson
masses in the region energies in which decay meson-meson thresholds are opened,
looking for the analogs to the $X(3872)$ in the $B_c$ spectroscopy. We use a
constituent quark model in which quark-antiquark degrees of freedom are
complemented by four-body Fock states configurations. The model has been
applied to a wide range of hadronic observables, in particular to the
$X(3872)$, and thus the model parameters are completely constrained. No extra
states are found in the $J^P=0^+$ and $J^P=1^+$ sectors. However, in the
$J^P=2^+$ sector we found an additional state very close to the $D^*B^*$
threshold which could be experimentally detected.
|
[
{
"created": "Wed, 22 Jan 2020 15:56:16 GMT",
"version": "v1"
},
{
"created": "Tue, 28 Jan 2020 11:44:57 GMT",
"version": "v2"
},
{
"created": "Tue, 18 Feb 2020 11:54:59 GMT",
"version": "v3"
}
] |
2020-04-22
|
[
[
"Ortega",
"Pablo G.",
""
],
[
"Segovia",
"Jorge",
""
],
[
"Entem",
"David R.",
""
],
[
"Fernandez",
"Francisco",
""
]
] |
The bottom-charmed ($B_c$) mesons are more stable than their charmonium ($c\bar c$) and bottomium ($b\bar b$) partners because they cannot annihilate into gluons. However, the low production cross-sections and signal-to-background ratios avoided until now their clear identification. The recent experimental results reported by CMS and LHCb at CERN open the possibility of having a $B_c$ spectrum as complete as the ones of charmonium and bottomonium. Motivated by this expectation, we compute bottom-charmed meson masses in the region energies in which decay meson-meson thresholds are opened, looking for the analogs to the $X(3872)$ in the $B_c$ spectroscopy. We use a constituent quark model in which quark-antiquark degrees of freedom are complemented by four-body Fock states configurations. The model has been applied to a wide range of hadronic observables, in particular to the $X(3872)$, and thus the model parameters are completely constrained. No extra states are found in the $J^P=0^+$ and $J^P=1^+$ sectors. However, in the $J^P=2^+$ sector we found an additional state very close to the $D^*B^*$ threshold which could be experimentally detected.
|
hep-ph/9802234
|
Mikhail Voloshin
|
B.M. Chibisov, M.B. Voloshin
|
Top quark longitudinal polarization near the threshold in l+ l-
annihilation
|
6 pages, LaTeX, no figures, added references, corrected typos
|
Mod.Phys.Lett. A13 (1998) 973-978
|
10.1142/S0217732398001042
|
TPI-MINN-98/02-T, UMN-TH-1623-98
|
hep-ph
| null |
We show that the longitudinal polarization of the top quarks produced in the
annihilation of e+ e- or mu+ mu- into tbar t at energies near the threshold is
not affected by the large Coulomb-type corrections, which greatly modify the
total cross section. Thus the longitudinal polarization, although small, may
provide an independent information on the mass and the width of the top quark,
largely independent of the uncertainty in alpha_s.
|
[
{
"created": "Tue, 3 Feb 1998 20:52:12 GMT",
"version": "v1"
},
{
"created": "Thu, 5 Feb 1998 23:00:58 GMT",
"version": "v2"
}
] |
2009-10-31
|
[
[
"Chibisov",
"B. M.",
""
],
[
"Voloshin",
"M. B.",
""
]
] |
We show that the longitudinal polarization of the top quarks produced in the annihilation of e+ e- or mu+ mu- into tbar t at energies near the threshold is not affected by the large Coulomb-type corrections, which greatly modify the total cross section. Thus the longitudinal polarization, although small, may provide an independent information on the mass and the width of the top quark, largely independent of the uncertainty in alpha_s.
|
2109.07851
|
Andreas Maier
|
Jeppe R. Andersen and Andreas Maier
|
Unbiased Elimination of Negative Weights in Monte Carlo Samples
|
22 pages, 7 figures
| null |
10.1140/epjc/s10052-022-10372-3
|
DCPT/21/54, DESY 21-135, IPPP/21/27, MCNET-21-14, SAGEX-21-29
|
hep-ph hep-ex
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We propose a novel method for the elimination of negative Monte Carlo event
weights. The method is process-agnostic, independent of any analysis, and
preserves all physical observables. We demonstrate the overall performance and
systematic improvement with increasing event sample size, based on predictions
for the production of a W boson with two jets calculated at next-to-leading
order perturbation theory.
|
[
{
"created": "Thu, 16 Sep 2021 10:31:52 GMT",
"version": "v1"
},
{
"created": "Mon, 16 May 2022 14:35:41 GMT",
"version": "v2"
}
] |
2022-06-01
|
[
[
"Andersen",
"Jeppe R.",
""
],
[
"Maier",
"Andreas",
""
]
] |
We propose a novel method for the elimination of negative Monte Carlo event weights. The method is process-agnostic, independent of any analysis, and preserves all physical observables. We demonstrate the overall performance and systematic improvement with increasing event sample size, based on predictions for the production of a W boson with two jets calculated at next-to-leading order perturbation theory.
|
1706.07046
|
Asher Berlin
|
Asher Berlin, Nikita Blinov
|
Thermal Dark Matter Below an MeV
|
5 pages, 4 figures; discussion and references added
|
Phys. Rev. Lett. 120, 021801 (2018)
|
10.1103/PhysRevLett.120.021801
|
SLAC-PUB-16989
|
hep-ph astro-ph.CO
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We consider a class of models in which thermal dark matter is lighter than an
MeV. If dark matter thermalizes with the Standard Model below the temperature
of neutrino-photon decoupling, equilibration and freeze-out cools and heats the
Standard Model bath comparably, alleviating constraints from measurements of
the effective number of neutrino species. We demonstrate this mechanism in a
model consisting of fermionic dark matter coupled to a light scalar mediator.
Thermal dark matter can be as light as a few keV, while remaining compatible
with existing cosmological and astrophysical observations. This framework
motivates new experiments in the direct search for sub-MeV thermal dark matter
and light force carriers.
|
[
{
"created": "Wed, 21 Jun 2017 18:00:00 GMT",
"version": "v1"
},
{
"created": "Fri, 2 Mar 2018 01:01:11 GMT",
"version": "v2"
}
] |
2018-03-05
|
[
[
"Berlin",
"Asher",
""
],
[
"Blinov",
"Nikita",
""
]
] |
We consider a class of models in which thermal dark matter is lighter than an MeV. If dark matter thermalizes with the Standard Model below the temperature of neutrino-photon decoupling, equilibration and freeze-out cools and heats the Standard Model bath comparably, alleviating constraints from measurements of the effective number of neutrino species. We demonstrate this mechanism in a model consisting of fermionic dark matter coupled to a light scalar mediator. Thermal dark matter can be as light as a few keV, while remaining compatible with existing cosmological and astrophysical observations. This framework motivates new experiments in the direct search for sub-MeV thermal dark matter and light force carriers.
|
hep-ph/9707501
|
Dar Arnon
|
Arnon Dar
|
Supernova 1987A - Ten Years After
|
Invited talk, to appear in the Proceedings of the 1997 Rencontre de
Physique de la Vallee d'Aoste, Italy
| null | null | null |
hep-ph astro-ph
| null |
Supernova 1987A became a milestone in physics and astronomy. The most
important things that have been learned from it, the most important problems
yet to be solved and the prospects for learning important new physics from
future observations of nearby supernova explosions are shortly summarized.
|
[
{
"created": "Tue, 29 Jul 1997 06:19:42 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Dar",
"Arnon",
""
]
] |
Supernova 1987A became a milestone in physics and astronomy. The most important things that have been learned from it, the most important problems yet to be solved and the prospects for learning important new physics from future observations of nearby supernova explosions are shortly summarized.
|
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