26 research outputs found
Tauonic B decays in the Minimal Supersymmetric Standard Model
We study new physics effects on B decay processes including a final
particle, namely and . An important feature
of these processes is that a charged Higgs boson can contribute to the decay
amplitude at the tree level in models such as Two Higgs Doublet Model and the
Minimal Supersymmetric Standard Model (MSSM). We derive a resummed effective
Lagrangian for charged-Higgs mediated interactions in the MSSM with the Minimal
Flavor Violation. Including supersymmetric (SUSY) loop corrections for
down-type-quark and charged-lepton Yukawa couplings, we calculate the branching
ratios of the and processes. We find that
SUSY correction due to gluino-sbottom diagrams can change the Higgs exchange
contribution by %, whereas stau-neutralino diagrams can make corrections
up to 20%. We also discuss relationship between SUSY corrections in the tauonic
decays and flavor changing neutral current processes such as and .Comment: 29 pages, 22 figure
No-Scale Scenarios in the Light of New Measurement of Muon Anomalous Magnetic Moment
Supersymmetric contribution to the muon anomalous magnetic moment a_\mu is
discussed in the no-scale-type supersymmetry breaking scenarios. Taking the
correlation between the supersymmetric contributions to a_\mu and Br(b\to
s\gamma), it is shown that the precise measurements of these quantities serve
an important constraint on the relative sign of the gaugino masses; combining
the 2.6-\sigma deviation in a_\mu from the standard-model prediction measured
by the E821 experiment and Br(b\to s\gamma) measured by CLEO, the sign of the
product M_2M_3 is strongly preferred to be positive, where M_2 and M_3 are
SU(2)_L and SU(3)_C gaugino mass parameters, respectively. In particular,
no-scale-type models with universal gaugino masses are in accord with the two
constraints and also with the Higgs mass bound. In addition, it is also shown
that future improvements in the measurements of a_\mu and Br(b\to s\gamma) may
provide serious test of the cases with M_2M_3<0.Comment: 10 pages, 4 figures, published versio
Low-Scale Anomalous U(1) and Decoupling Solution to Supersymmetric Flavor Problem
Supersymmetric standard models where the ultraviolet cut-off scale is only a
few orders of magnitude higher than the electroweak scale are considered.
Phenomenological consequences of this class of models are expected to be very
different from, for example, the conventional supergravity scenario. We apply
this idea to a model with an anomalous U(1) gauge group and construct a viable
model in which some difficulties of the decoupling solution to the
supersymmetric flavor problem are ameliorated.Comment: 15 pages, 1 figur
Recent Result from E821 Experiment on Muon g-2 and Unconstrained Minimal Supersymemtric Standard Model
Recently, the E821 experiment at the Brookhaven National Laboratory announced
their latest result of their muon g-2 measurement which is about 2.6-\sigma
away from the standard model prediction. Taking this result seriously, we
examine the possibility to explain this discrepancy by the supersymmetric
contribution. Our analysis is performed in the framework of the unconstrained
supersymmetric standard model which has free seven parameters relevant to muon
g-2. We found that, in the case of large \tan\beta, sparticle masses are
allowed to be large in the region where the SUSY contribution to the muon g-2
is large enough, and hence the conventional SUSY search may fail even at the
LHC. On the contrary, to explain the discrepancy in the case of small
\tan\beta, we found that (i) sleptons and SU(2)_L gauginos should be light, and
(ii) negative search for the Higgs boson severely constrains the model in the
framework of the mSUGRA and gauge-mediated model.Comment: 10 pages, 5 figure
Bottom-Tau Unification in SUSY SU(5) GUT and Constraints from b to s gamma and Muon g-2
An analysis is made on bottom-tau Yukawa unification in supersymmetric (SUSY)
SU(5) grand unified theory (GUT) in the framework of minimal supergravity, in
which the parameter space is restricted by some experimental constraints
including Br(b to s gamma) and muon g-2. The bottom-tau unification can be
accommodated to the measured branching ratio Br(b to s gamma) if superparticle
masses are relatively heavy and higgsino mass parameter \mu is negative. On the
other hand, if we take the latest muon g-2 data to require positive SUSY
contributions, then wrong-sign threshold corrections at SUSY scale upset the
Yukawa unification with more than 20 percent discrepancy. It has to be
compensated by superheavy threshold corrections around the GUT scale, which
constrains models of flavor in SUSY GUT. A pattern of the superparticle masses
preferred by the three requirements is also commented.Comment: 21pages, 6figure
Supersymmetric Relations Among Electromagnetic Dipole Operators
Supersymmetric contributions to all leptonic electromagnetic dipole operators
have essentially identical diagramatic structure. With approximate slepton
universality this allows the muon anomalous magnetic moment to be related to
the electron electric dipole moment in terms of supersymmetric phases, and to
radiative flavor changing lepton decays in terms of small violations of slepton
universality. If the current discrepancy between the measured and Standard
Model values of the muon anomalous magnetic moment is due to supersymmetry, the
current bound on the electron electric dipole moment then implies that the
phase of the electric dipole operator is less than . Likewise
the current bound on decay implies that the fractional
selectron-smuon mixing in the left-left mass squared matrix, \delta m_{\smuon
\selectron}^2 / m_{\slepton}^2, is less than . These relations and
constraints are fairly insensitive to details of the superpartner spectrum for
moderate to large .Comment: Latex, 38 pages, 2 figure
Exercise training enhances in vivo clearance of endotoxin and attenuates inflammatory responses by potentiating Kupffer cell phagocytosis
The failure of Kupffer cells (KCs) to remove endotoxin is an important factor in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). In this study, the effects of exercise training on KC function were studied in terms of in vivo endotoxin clearance and inflammatory responses. Mice were allocated into rest and exercise groups. KC bead phagocytic capacity and plasma steroid hormone levels were determined following exercise training. Endotoxin and inflammatory cytokine levels in plasma were determined over time following endotoxin injection. KC bead phagocytic capacity was potentiated and clearance of exogenously-injected endotoxin was increased in the exercise group. Inflammatory cytokine (TNF-α and IL-6) levels were lower in the exercise group. We found that only DHEA was increased in the plasma of the exercise group. In an in vitro experiment, the addition of DHEA to RAW264.7 cells increased bead phagocytic capacity and attenuated endotoxin-induced inflammatory responses. These results suggest that exercise training modulates in vivo endotoxin clearance and inflammatory responses in association with increased DHEA production. These exercise-induced changes in KC capacity may contribute to a slowing of disease progression in NAFLD patients
Higgs-mediated muon-electron conversion process in supersymmetric seesaw model
We study the effect of the Higgs-exchange diagram for the lepton flavor
violating muon-electron conversion process in nuclei in the supersymmetric
seesaw model. The contribution is significant for a large value of tan beta and
a small value of a neutral heavy Higgs boson mass, in which case the ratio of
the branching ratios of B(mu N -> e N) / B(mu -> e gamma) is enhanced. We also
show that the target atom dependence of the conversion branching ratio provides
information on the size of the Higgs exchange diagram.Comment: 12 pages, 2 figures, a reference adde
CP Violation in Kaon System in Supersymmetric SU(5) Model with Seesaw-Induced Neutrino Masses
CP violations in the kaon system are studied in supersymmetric SU(5) model
with right-handed neutrinos. We pay a special attention to the renormalization
group effect on the off-diagonal elements of the squark mass matrices. In
particular, if the Yukawa couplings and mixings in the neutrino sector are
sizable, off-diagonal elements of the right-handed down-type squark mass matrix
are generated, which affect CP and flavor violations in decay processes of the
kaon. We calculate supersymmetric contributions to epsilon (as well as Delta
m_K), Br(K_L -> pi^0 nu \bar{nu}), and epsilon'/epsilon in this framework. We
will see that the supersymmetric contribution to the epsilon parameter can be
as large as (and in some case, larger than) the experimentally measured value.
We also discuss its implication to future tests of the unitarity triangle of
the Kobayashi-Maskawa matrix.Comment: 30 pages, 5 figue