Successful type I leptogenesis with SO(10)-inspired mass relations

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 front 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-anti matter asymmetry. In particular we find m(1) greater than or similar to 10(-3) eV, where m(1) is the mass of the lightest left-handed neutrino and that non-vanishing values of the mixing angle theta(13) are preferred in the case of a normal fully hierarchical spectrum of light neutrinos. (C) 2008 Elsevier B.V. All rights reserved.