Leptogenesis in the light of Super-Kamiokande data and a realistic string model

We discuss leptogenesis in the light of indications of neutrino masses and mixings from Super-Kamiokande and other data on atmospheric neutrinos, as w ell as the solar neutrino deficit. Neutrino masses and mixings consistent w ith these data may produce in a natural and generic way a lepton asymmetry that is sufficient to provide the observed baryon asymmetry, after processi ng via non-perturbative electroweak effects. We illustrate this discussion in the framework of the string-derived flipped SU(5) model, using particle assignments and choices of vacuum parameters that are known to give realist ic masses to quarks and charged leptons. We display one scenario for neutri no masses that also accommodates leptogenesis. (C) 1999 Published by Elsevi er Science B.V. All rights reserved.