1,958 research outputs found
Footprints of Supersymmetry on Higgs Decay
Motivated by future collider proposals that aim to measure the Higgs
properties precisely, we study the partial decay widths of the lightest Higgs
boson in the minimal supersymmetric standard model with an emphasis on the
parameter region where all superparticles and heavy Higgs bosons are not
accessible at the LHC. Taking account of phenomenological constraints such as
the Higgs mass, flavor constraints, vacuum stability, and perturbativity of
coupling constants up to the grand unification scale, we discuss how large the
deviations of the partial decay widths from the standard model predictions can
be. These constraints exclude large fraction of the parameter region where the
Higgs widths show significant deviation from the standard model predictions.
Nevertheless, even if superparticles and the heavy Higgses are out of the reach
of 14TeV LHC, the deviation may be large enough to be observed at future
collider experiments.Comment: 24 pages, 8 figures, version accepted in JHE
Supersymmetric Heavy Higgses at e^+e^- Linear Collider and Dark-Matter Physics
We consider the capability of the e^+e^- linear collider (which is recently
called as the International Linear Collider, or ILC) for studying the
properties of the heavy Higgs bosons in the supersymmetric standard model. We
pay special attention to the large \tan\beta region which is motivated, in
particular, by explaining the dark-matter density of the universe (i.e.,
so-called ``rapid-annihilation funnels''). We perform a systematic analysis to
estimate expected uncertainties in the masses and widths of the heavy Higgs
bosons assuming an energy and integrated luminosity of \sqrt{s}=1 TeV and L=1
ab^{-1}. We also discuss its implication to the reconstruction of the
dark-matter density of the universe.Comment: 28 pages, 13 figures, version to appear in PR
Gravitino Dark Matter with Weak-Scale Right-Handed Sneutrino
We consider cosmological implications of supersymmetric models with
right-handed (s)neutrinos where the neutrino masses are purely Dirac-type. We
pay particular attention to the case where gravitino is the lightest
superparticle while one of the right-handed sneutrinos is next-to-the-lightest
superparticle. We study constraints from big-bang nuleosynthesis and show that
the constraints could be relaxed compared to the case without right-handed
sneutrinos. As a result, the gravitino-dark-matter scenario becomes viable with
relatively large value of the gravitino mass. We also discuss constraints from
the structure formation; in our model, the free-streaming length of the
gravitino dark matter may be as long as O(1 Mpc), which is comparable to the
present observational upper bound on the scale of free-streaming.Comment: 18 pages, 6 figure
Renormalization-Scale Uncertainty in the Decay Rate of False Vacuum
We study radiative corrections to the decay rate of false vacua, paying
particular attention to the renormalization-scale dependence of the decay rate.
The decay rate exponentially depends on the bounce action. The bounce action
itself is renormalization scale dependent. To make the decay rate
scale-independent, radiative corrections, which are due to the field
fluctuations around the bounce, have to be included. We show quantitatively
that the inclusion of the fluctuations suppresses the scale dependence, and
hence is important for the precise calculation of the decay rate. We also apply
our analysis to a supersymmetric model and show that the radiative corrections
are important for the Higgs-stau system with charge breaking minima.Comment: 15 pages, 2 figures; added reference
On the Gauge Invariance of the Decay Rate of False Vacuum
We study the gauge invariance of the decay rate of the false vacuum for the
model in which the scalar field responsible for the false vacuum decay has
gauge quantum number. In order to calculate the decay rate, one should
integrate out the field fluctuations around the classical path connecting the
false and true vacua (i.e., so-called bounce). Concentrating on the case where
the gauge symmetry is broken in the false vacuum, we show a systematic way to
perform such an integration and present a manifestly gauge-invariant formula of
the decay rate of the false vacuum.Comment: 17 pages, published versio
The 19-Vertex Model at critical regime
We study the 19-vertex model associated with the quantum group
at critical regime . We give the realizations of the
type-I vertex operators in terms of free bosons and free fermions. Using these
free field realizations, we give the integral representations for the
correlation functions.Comment: LaTEX2e, 19page
Higher-dimensional WZW Model on K\"ahler Manifold and Toroidal Lie Algebra
We construct a generalization of the two-dimensional Wess-Zumino-Witten model
on a -dimensional K\"ahler manifold as a group-valued non-linear sigma
model with an anomaly term containing the K\"ahler form. The model is shown to
have an infinite-dimensional symmetry which generates an -toroidal Lie
algebra. The classical equation of motion turns out to be the
Donaldson-Uhlenbeck-Yau equation, which is a -dimensional generalization of
the self-dual Yang-Mills equation.Comment: 12 pages, Late
Diagonalization of infinite transfer matrix of boundary face model
We study infinitely many commuting operators , which we call infinite
transfer matrix of boundary face model. We diagonalize
infinite transfer matrix by using free field realizations of the
vertex operators of the elliptic quantum group .Comment: 36 pages, Dedicated to Professor Etsuro Date on the occassion of the
60th birthda
Difference equations for the higher rank XXZ model with a boundary
The higher rank analogue of the XXZ model with a boundary is considered on
the basis of the vertex operator approach. We derive difference equations of
the quantum Knizhnik-Zamolodchikov type for 2N-point correlations of the model.
We present infinite product formulae of two point functions with free boundary
condition by solving those difference equations with N=1.Comment: LaTEX 16 page
Synchrotron Radiation from the Galactic Center in Decaying Dark Matter Scenario
We discuss the synchrotron radiation flux from the Galactic center in
unstable dark matter scenario. Motivated by the anomalous excess of the
positron fraction recently reported by the PAMELA collaboration, we consider
the case that the dark matter particle is unstable (and long-lived), and that
energetic electron and positron are produced by the decay of dark matter. Then,
the emitted electron and positron becomes the source of the synchrotron
radiation. We calculate the synchrotron radiation flux for models of decaying
dark matter, which can explain the PAMELA positron excess. Taking the lifetime
of the dark matter of O(10^26 sec), which is the suggested value to explain the
PAMELA anomaly, the synchrotron radiation flux is found to be O(1 kJy/str) or
smaller, depending on the particle-physics and cosmological parameters.Comment: 20 pages, 6 figure
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