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

Possible Signals of Wino LSP at the Large Hadron Collider

We consider a class of anomaly-mediated supersymmetry breaking models where gauginos acquire masses mostly from anomaly mediation while masses of other superparticles are from Kahler interactions, which are as large as gravitino mass, O(10-100) TeV. In this class of models, the neutral Wino becomes the lightest superparticle in a wide parameter region. The mass splitting between charged and neutral Winos are very small and experimental discovery of such Winos is highly non-trivial. We discuss how we should look for Wino-induced signals at Large Hadron Collider.Comment: 15 pages, 3 figure

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

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

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

Conformal Gauge Mediation

We propose a one-parameter theory for gauge mediation of supersymmetry (SUSY) breaking. The spectrum of SUSY particles such as squarks and sleptons in the SUSY standard-model and the dynamics of SUSY-breaking sector are, in principle, determined only by one parameter in the theory, that is, the mass of messengers. Above the messenger threshold all gauge coupling and Yukawa coupling constants in the SUSY-breaking sector are on the infrared fixed point. We find that the present theory may predict a split spectrum of the standard-model SUSY particles, m_{gaugino} < m_{sfermion}, where m_{gaugino} and m_{sfermion} are SUSY-breaking masses for gauginos and squarks/sleptons, respectively.Comment: 17 page

Minimal Supergravity, Inflation, and All That

We consider an inflationary model in the hidden-sector broken supergravity with an effectively large cutoff. The inflaton decay into right-handed neutrinos naturally causes the observed baryon asymmetry of the universe with a reheating temperature low enough to avoid the gravitino overproduction. We emphasize that all the phenomenological requirements from cosmology and particle physics are satisfied in the large-cutoff theory.Comment: 15pages, 4figures, text and refs. adde

Conformal Gauge Mediation and Light Gravitino of Mass m_{3/2} <O(10) eV

We discuss a class of gauge mediated supersymmetry breaking models with conformal invariance above the messenger mass scale (conformal gauge mediation). The spectrum of the supersymmetric particles including the gravitino is uniquely determined by the messenger mass. When the conformal fixed point is strongly interacting, it predicts a light gravitino of mass m_{3/2}<O(10) eV, which is attractive since such a light gravitino causes no problem in cosmology.Comment: 14 page