26 research outputs found
Probing the messenger of supersymmetry breaking by the muon anomalous magnetic moment
Motivated by the recently measured muon's anomalous magnetic moment
, we examine the supersymmetry contribution to in various
mediation models of supersymmetry breaking which lead to predictive flavor
conserving soft parameters at high energy scale. The studied models include
dilaton/modulus-mediated models in heterotic string/ theory, gauge-mediated
model, no-scale or gaugino-mediated model, and also the minimal and deflected
anomaly-mediated models. For each model, the range of allowed
by other experimental constraints, e.g. b --> s\gamma and the collider bounds
on superparticle masses, is obtained together with the corresponding parameter
region of the model. Gauge-mediated models with low messenger scale can give
any within the bound. In many other models, b -->
s\gamma favors smaller than either the value
() or the central value ().Comment: RevTeX, 29 pages, 14 eps figures, figure for deflected anomaly
mediation is corrected, reference adde
Higgsino mass matrix ansatz for MSSM
An ansatz, Det. for the Higgsino mass matrix in string
orbifold trinification is suggested toward the minimal supersymmetric standard
model(MSSM). Small instanton solutions effective around the GUT scale can
fulfil this condition. An argument that the couplings contain a moduli field is
given for a dynamical realization of this Higgsino mass matrix ansatz.Comment: 15 pages of LaTeX fil
String theoretic axion coupling and the evolution of cosmic structures
We examine the effects of the axion coupling to on the evolution
of cosmic structures. It is shown that the evolutions of the scalar- and
vector-type perturbations are not affected by this axion coupling. However the
axion coupling causes an asymmetric evolution of the two polarization states of
the tensor-type perturbation, which may lead to a sizable polarization
asymmetry in the cosmological gravitational wave if inflation involves a period
in which the axion coupling is important. The polarization asymmetry produced
during inflation are conserved over the subsequent evolution as long as the
scales remain in the large-scale limit, and thus this may lead to an observable
trace in the cosmic microwave background radiation.Comment: 10 pages, REVte
Sneutrino-Antisneutrino Mixing and Neutrino Mass in Anomaly--mediated Supersymmetry Breaking Scenario
In supersymmetric models with nonzero Majorana neutrino mass, the sneutrino
and antisneutrino mix, which may lead to same sign dilepton signals in future
collider experiments. We point out that the anomaly-mediated supersymmetry
breaking scenario has a good potential to provide an observable rate of such
signals for the neutrino masses suggested by the atmospheric and solar neutrino
oscillations. The sneutrino mixing rate is naturally enhanced by
m_{3/2}/m_{\tilde{\nu}}={\cal O}(4\pi/\alpha) while the sneutrino decay rate is
small enough on a sizable portion of the parameter space. We point out also
that the sneutrino-antisneutrino mixing can provide much stronger information
on some combinations of the neutrino masses and mixing angles than neutrino
experiments.Comment: Revtex, 13 pages, 2 figure