GUT Scale Inflation, Non-Thermal Leptogenesis, and Atmospheric Neutrino Oscillations

Leptogenesis scenarios in supersymmetric hybrid inflation models are considered. Sufficient lepton asymmetry leading to successful baryogenesis can be obtained if the reheat temperature T_r>10^6 GeV and the superpotential coupling parameter kappa is in the range 10^-6<kappa<10^-2. For this range of kappa the scalar spectral index n_s=0.99±0.01. Constraints from neutrino mixing further restrict the range of kappa that is allowed. We analyze in detail the case where the inflaton predominantly decays into the next-to-lightest right handed Majorana neutrino taking into account especially the constraints from atmospheric neutrino oscillations.