The degenerate gravitino scenario

We propose an alternative solution to the gravitino problem in supersymmetric theories. In the 'degenerate gravitino' scenario the mass difference between the gravitino and the LOSP (lightest ordinary MSSM particle) is much smaller than the gravitino mass itself. As a consequence, the energy released in the decay of the next to lightest sypersymmetric particle (NLSP) is reduced. The cosmological and astrophysical constraints on the gravitino abundance, and hence on the reheating temperature, become softer than in the usual case. We explore the parameter space of this scenario and confront it with the above mentioned constraints. In the case of neutralinos LOSP, mass splittings of order 10-2 GeV are possible, while for stau LOSP the splitting can be of order tens of GeVs. In both cases, maximal reheating temperatures, compatible with thermal leptogenesis are reached.