831 research outputs found
A New Inflation Model with Anomaly-mediated Supersymmetry Breaking
If there are a large number of vacua, multi-inflation may be a more mediocre
phenomenon rather than a single inflation. In the multi-inflation scenario, new
inflation is most likely the last inflation, since its energy scale is
naturally low. Furthermore, it may explain the observed spectral index of the
cosmic microwave background radiations. We show, in this letter, that a new
inflation model proposed in supergravity accounts for all the present
observations assuming anomaly mediation of supersymmetry breaking. As a result,
we find that the relic density of the winos is consistent with the observed
dark matter density in a wide range of the wino mass, 100 GeV lsim m_{tilde{w}}
lsim 2 TeV, albeit for a low reheating temperature T_{R} simeq 10^{6-7},GeV.Comment: 14 pages, 4 figures, the title is correcte
R-invariant New Inflation Model vs Supersymmetric Standard Model
We revisit the implications of the R-invariant New Inflation model to the
supersymmetric standard model in light of recent discussion of gravitino
production processes by the decay of the inflaton or the supersymmetry breaking
field. We show that the models with supergravity mediation do not go well with
the R-invariant New Inflation model, where the gravitino abundance produced by
the decay of the inflaton or the supersymmetry breaking field significantly
exceeds the bounds from cosmological observations without fine-tuning. We also
show that the models with gauge mediation can go together with R-invariant New
Inflation model, where the dark matter and the baryon asymmetry are
consistently explained without severe fine-tuning.Comment: 19 pages, 3 figure
Strongly Coupled Semi-Direct Mediation of Supersymmetry Breaking
Strongly coupled semi-direct gauge mediation models of supersymmetry breaking
through massive mediators with standard model charges are investigated by means
of composite degrees of freedom. Sizable mediation is realized to generate the
standard model gaugino masses for a small mediator mass without breaking the
standard model symmetries.Comment: 7 pages; v2: the model generalized, gaugino mass corrected; v3:
explanations expanded, references adde
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
The Polonyi Problem and Upper bound on Inflation Scale in Supergravity
We reconsider the Polonyi problem in gravity-mediation models for
supersymmetry (SUSY) breaking. It has been argued that there is no problem in
the dynamical SUSY breaking scenarios, since the Polonyi field acquires a
sufficiently large mass of the order of the dynamical SUSY-breaking scale
Lamada_{SUSY}. However, we find that a linear term of the Polonyi field in the
Kahler potential brings us back to the Polonyi problem, unless the inflation
scale is sufficiently low, H_{inf} < 10^{8} GeV, or the reheating temperature
is extremely low, T_{R} < 100 GeV. Here, this Polonyi problem is more serious
than the original one, since the Polonyi field mainly decays into a pair of
gravitinos.Comment: 17 pages, 1 figure, minor corrections, published versio
A 125GeV Higgs Boson and Muon g-2 in More Generic Gauge Mediation
Recently, the ATLAS and CMS collaborations reported exciting hints of a
Standard Model-like Higgs boson with a mass around 125GeV. A Higgs boson this
heavy is difficult to realize in conventional models of gauge mediation. Here
we revisit the lightest Higgs boson mass in "more generic gauge mediation,"
where the Higgs doublets mix with the messenger doublets. We show that a Higgs
boson mass around 125GeV can be realized in more generic gauge mediation
models, even for a relatively light gluino mass ~1TeV. We also show that the
muon anomalous magnetic moment can be within 1sigma of the experimental value
for these models, even when the Higgs boson is relatively heavy. We also
discuss the LHC constraints and the prospects of discovery.Comment: 28 pages, 7 figures. Corrections and references are adde
Dark Matter and Pseudo-flat Directions in Weakly Coupled SUSY Breaking Sectors
We consider candidates for dark matter in models of gauge mediated
supersymmetry breaking, in which the supersymmetry breaking sector is weakly
coupled and calculable. Such models typically contain classically flat
directions, that receive one-loop masses of a few TeV. These pseudo-flat
directions provide a new mechanism to account for the cold dark matter relic
abundance. We discuss also the possibility of heavy gravitino dark matter in
such models.Comment: 16 pages, 2 figures. v2: comments, refs adde
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