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 Planck scale Mp, whereas the auxiliary "orthogonal" field must be close to zero with an extreme accuracy. This problem can be alleviated if the orthogonal 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 offers an interesting mechanism for generating a correct amount of lepton asymmetry, which being reprocessed by sphalerons can explain the observed baryon asymmetry of the Universe. Our scenario implies interesting bounds for the neutrino masses in the context of seesaw mechanism. (C) 2001 Elsevier Science B.V. All rights reserved.