70 research outputs found
R-Invariant Dilaton Fixing
We consider dilaton stabilization with R invariance, which insures a
vanishing cosmological constant at the scale of stabilization. We construct a
few models which accommodate weak gauge couplings with large or small gauge
groups. Matter condensation plays a central role in the dilaton stabilization.Comment: 8 pages, references adde
A Gauge-Mediation Model with a Light Gravitino of Mass O(10) eV and the Messenger Dark Matter
In the light of recent experimental data on gaugino searches, we revisit the
direct-transmission model of dynamical supersymmery breaking with the gravitino
mass m_{\tilde{G}}\leq 16 eV, which does not have any cosmological or
astrophysical problems. We find that in the consistent regions of parameter
space, the model predicts not only upper bounds on superparticle masses (1.1
TeV, 320 GeV, 160 GeV, 5 TeV, 1.5 TeV and 700 GeV for gluino, Wino, Bino,
squarks, left-handed sleptons and right-handed sleptons, respectively), but
also a mass of the lightest messenger particle in the range of 10-50 TeV. The
lightest messenger particle can naturally be a messenger sneutrino. Therefore,
this may suggest that the messenger sneutrino could be the dark matter, as
proposed recently by Hooper and March-Russel to account for the gamma-ray
spectrum from the galactic center observed by HESS experiment.Comment: 11 pages, 3 figure
Neutrino-induced lepton flavor violation in gauge-mediated supersymmetry breaking
Gauge-mediated supersymmetry breaking is known to greatly suppress flavor
changing neutral current effects. However, we show that gauge mediation in the
context of leptogenesis implies potentially large lepton flavor violating
signals. If the heavy right-handed neutrinos that participate in leptogenesis
are lighter than the messenger scale of gauge mediation, they will induce
flavor off-diagonal masses to the sleptons which in turn can induce large
effects in mu to e gamma, tau to mu gamma, and mu-e conversion in nuclei. We
demonstrate this result and compute numerically the lepton-flavor violating
decay and conversion rates in scenarios of direct gauge mediation.Comment: 18 pages, 5 figure
Eluding the Gravitino Overproduction in Inflaton Decay
It is known that gravitinos are non-thermally produced in inflaton decay
processes, which excludes many inflation models for a wide range of the
gravitino mass. We find that the constraints from the gravitino overproduction
can be greatly relaxed if the supersymmetry breaking field is much lighter than
the inflaton, and if the dynamical scale of the supersymmetry breaking is
higher than the inflaton mass. In particular, we show that many inflation
models then become consistent with the pure gravity mediation with O(100)TeV
gravitino which naturally explains the recently observed Higgs boson mass of
about 125GeV.Comment: 19 pages, 2 figures; to appear in Phys.Lett.
Effects of home-based exercise on pre-dialysis chronic kidney disease patients: a randomized pilot and feasibility trial
Simplified R-Symmetry Breaking and Low-Scale Gauge Mediation
We argue that some of the difficulties in constructing realistic models of
low-scale gauge mediation are artifacts of the narrow set of models that have
been studied. In particular, much attention has been payed to the scenario in
which the Goldstino superfield in an O'Raifeartaigh model is responsible for
both supersymmetry breaking and R-symmetry breaking. In such models, the
competing problems of generating sufficiently massive gauginos while preserving
an acceptably light gravitino can be quite challenging. We show that by sharing
the burdens of breaking supersymmetry and R-symmetry with a second field, these
problems are easily solved even within the O'Raifeartaigh framework. We present
explicit models realizing minimal gauge mediation with a gravitino mass in the
eV range that are both calculable and falsifiable.Comment: 31 pages, 4 figures, references added, minor change
Dark Matter from Split Seesaw
The seesaw mechanism in models with extra dimensions is shown to be
generically consistent with a broad range of Majorana masses. The resulting
democracy of scales implies that the seesaw mechanism can naturally explain the
smallness of neutrino masses for an arbitrarily small right-handed neutrino
mass. If the scales of the seesaw parameters are split, with two right-handed
neutrinos at a high scale and one at a keV scale, one can explain the
matter-antimatter asymmetry of the universe, as well as dark matter. The dark
matter candidate, a sterile right-handed neutrino with mass of several keV, can
account for the observed pulsar velocities and for the recent data from Chandra
X-ray Observatory, which suggest the existence of a 5 keV sterile right-handed
neutrino.Comment: 15 pages. v2: references added, a version accepted by PL
Cancer of the Pancreas in 125 Patients
In this report, we did a retrospective study of 125 patients with cancer of the pancreas. Seventeen (36.2%) of the 47 patients with cancer of the pancreatic head underwent resection; 11.2% died within 30 days of surgery, 33.3 survived the first year, and 13.3 survived the first three years. The longest survival was for five years. Nine (23%) of the 39 patients with cancer of the pancreatic body and tail underwent resection; 11.1% died within 30 days, 37.5% survived the first year, and none survived more than three years. The longest survival was for 35 months. Important factors affecting the prognosis were invasion by the cancer of veins or lymph vessels in the surrounding tissues, and metastasis to regional lymph nodes. Lymphatic drainage of small cancers of the pancreatic head were established early. Invasion to the retroperitoneal tissue in cancer of the pancreatic body and tail was more common than in cancer of the pancreatic head. For the patient of early cancer of the pancreas, we strongly recommend total pancreatectomy over WHIPPLE\u27s pancreatoduodenectomy, based on results of our analysis of the outcome in our patients following these two operations. Key words: Cancer of the pancreas, Total pancreatectomy, WHIPPLE\u27s pancreatoduodenectom
Higgs Boson Mass in Low Scale Gauge Mediation Models
We consider low scale gauge mediation models with a very light gravitino
m_{3/2}~16 eV, in the light of recent experimental hints on the Higgs boson
mass. The light gravitino is very interesting since there is no gravitino
over-production problem, but it seems difficult to explain the Higgs boson mass
of ~125 GeV. This is because of the conflict between the light gravitino mass
and heavy SUSY particle masses needed for producing the relatively heavy Higgs
boson mass. We consider two possible extensions in this paper: a singlet
extension of the Higgs sector, and strongly coupled gauge mediation. We show
that there is a large parameter space, in both scenarios, where the Higgs boson
mass of ~125 GeV is explained without any conflict with such a very light
gravitino.Comment: 23 pages, 5 figure
The Lightest Higgs Boson Mass in Pure Gravity Mediation Model
We discuss the lightest Higgs boson mass in the minimal supersymmetric
Standard Model with "pure gravity mediation". By requiring that the model
provides the observed dark matter density, we find that the lightest Higgs
boson is predicted to be below 132GeV. We also find that the upper limit on the
lightest Higgs boson mass becomes 128GeV, if we further assume thermal
leptogenesis mechanism as the origin of baryon asymmetry of universe. The
interrelations between the Higgs boson mass and the gaugino masses are also
discussed.Comment: 18 pages, 5 figures, minor correction
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