Related papers: The Case for an EeV Gravitino
Motivated by the absence of signals of new physics in both searches for new particles at LHC and for a Weakly Interacting Massive Particle (WIMP) dark matter candidate, we consider a scenario where supersymmetry is broken at a scale above…
The production and the final abundance of gravitino dark matter appear to depend crucially on the restoration of the global U(1) $R$-symmetry of GMSB sectors in a threefold way. An $R$-symmetric phase effectively suppresses the production…
We discuss the gravitino problem in contest of the Exotic see-saw mechanism for neutrinos and Leptogenesis, UV completed by intersecting D-branes Pati-Salam models. In the Exotic see-saw model, supersymmetry is broken at high scales…
We propose a novel reformulation of supersymmetric (more precisely $\mu$-) hybrid inflation based on a local U(1) or any suitable extension of the minimal supersymmetric standard model (MSSM) which also resolves the $\mu$ problem. We employ…
The scale at which supersymmetry is broken and the mechanism by which supersymmetry breaking is fed down to the observable sector has rich implications on the way Nature may have chosen to accomplish inflation. We discuss a simple model for…
In all supersymmetric theories, gravitinos, with mass suppressed by the Planck scale, are an obvious candidate for dark matter; but if gravitinos ever reached thermal equilibrium, such dark matter is apparently either too abundant or too…
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…
We derive cosmological constraints on the masses of generic scalar fields which decay only through gravitationally suppressed interactions into unstable gravitinos and ordinary particles in the supersymmetric standard model. For the…
We reconsider the problems of cosmological inflation in effective supergravity theories. A singlet field in a hidden sector is demonstrated to yield an acceptable inflationary potential, without fine tuning. In the simplest such model, the…
We point out that there is no cosmological gravitino problem in a certain class of gauge-mediated supersymmetry-breaking (GMSB) models. The constant term in the superpotential naturally causes small mixings between the standard-model and…
We consider the abundance of gravitinos created from the vacuum fluctuation, in a class of `new' inflation models for which global supersymmetry is a good approximation. Immediately after inflation, gravitinos are produced, with number…
We show that an oscillating scalar field in supergravity of mass of the order of $\sim$ TeV with a nonzero vacuum expectation value ($\sim 10^{10}$ GeV) can be a candidate of cold dark matter (CDM). To avoid the gravitino problem, we need a…
We investigate an inflation model with the inflaton being identified with a Higgs boson responsible for the breaking of U(1)B-L symmetry. We show that supersymmetry must remain a good symmetry at scales one order of magnitude below the…
Present data require a spectral index $n\gsim 0.95$ at something like 1-$\sigma$ level. If this lower bound survives it will constrain `new' and `modular' inflation models, while raising it to 1.00 would rule out all of these models plus…
It is quite possible that the reheat temperature of the universe is extremely low close to the scale of Big Bang nucleosynthesis, i.e. $T_{R}\sim 1-10$ MeV. At such low reheat temperatures generating matter anti-matter asymmetry and…
We discuss gravitino production from reheating in models where the splitting between particle and sparticle masses can be larger than TeV, as naturally arising in the context of split supersymmetry. We show that such a production typically…
We discuss the upper bound on the gluino mass in supersymmetric models with vector-like extra matters. In order to realize the observed Higgs mass of 125 GeV, the gluino mass is bounded from above in supersymmetric models. With the…
In some supergravity models, the superlight gravitino is accompanied by a light weakly coupled scalar (S) and pseudo-scalar (P) particle. The coupling of these particles to matter is inversely proportional to the product of the gravitino…
The viability of a possible cosmological scenario is investigated. The theoretical framework is the constrained next-to-minimal supersymmetric standard model (cNMSSM), with a gravitino playing the role of the lightest supersymmetric…
We elaborate on a minimal inflation scenario based entirely on the general properties of supersymmetry breaking in supergravity models. We identify the inflaton as the scalar component of the Goldstino superfield. We write plausible…