Supersymmetric model of neutrino mass and leptogenesis with string-scale unification

Abstract

Adjoint supermultiplets (1,3,0) and (8,1,0) modify the evolution of gauge couplings. If the unification of gauge couplings occurs at the string scale, their masses are fixed at around 10¹³ GeV. This scale coincides with expected gaugino condensation scale in the hidden sector M_string ^⅔m^⅓_3/2~10¹³ GeV. We show how neutrino masses arise in this unified model which naturally explain the present atmospheric and solar neutrino data. The out-of-equilibrium decay of the superfield (1,3,0) at 10¹³ GeV may also lead to a lepton asymmetry which then gets converted into the present observed baryon asymmetry of the Universe.