Affleck-Dine leptogenesis via right-handed sneutrino fields in a supersymmetric hybrid inflation model

The onset of inflation in hybrid models require fine tuning in the initial conditions. The inflaton field should have an initial value close to the Pl anck scale Mp, whereas the auxiliary "orthogonal" field must be close to ze ro with an extreme accuracy. This problem can be alleviated if the orthogon al field decays fast into some states not coupled to the inflaton. Natural candidates for such states can be the right-handed neutrinos. We show that a non-trivial evolution of the classic sneutrino fields after inflation off ers an interesting mechanism for generating a correct amount of lepton asym metry, which being reprocessed by sphalerons can explain the observed baryo n asymmetry of the Universe. Our scenario implies interesting bounds for th e neutrino masses in the context of seesaw mechanism. (C) 2001 Elsevier Sci ence B.V. All rights reserved.