Successful type I leptogenesis with [formula omitted]-inspired mass relations

Abstract

It is well known that thermal leptogenesis through the decays of the lightest right-handed neutrinos encounters serious difficulties when SO ( 10 ) -inspired mass conditions are imposed on the Dirac neutrino mass matrix and light neutrino masses are generated through the type I see-saw mechanism. We show that these can be circumvented when the production from the next-to-lightest right-handed neutrinos and flavor effects are properly taken into account. Some conditions on the low energy parameters have to be satisfied in order to explain the observed matter–antimatter asymmetry. In particular we find m 1 ≳ 10 −3 eV , where m 1 is the mass of the lightest left-handed neutrino and that non-vanishing values of the mixing angle θ 13 are preferred in the case of a normal fully hierarchical spectrum of light neutrinos.