Fermion masses, Leptogenesis and Supersymmetric SO(10) Unification

Abstract

Current neutrino oscillation data indicate the existence of two large lepton mixing angles, while Kobayashi-Maskawa matrix elements are all small. Here we show how supersymmetric SO(10) with extra chiral singlets can easily reconcile large lepton mixing angles with small quark mixing angles within the framework of the successful Fritzsch ansatz. Moreover we show how this is fully consistent with the thermal leptogenesis scenario, avoiding the so-called gravitino problem. A sizeable asymmetry can be generated at relatively low scales. We present our results in terms of the leptonic CP violation parameter that characterizes neutrino oscillations.

18 pages, 9 figures, 1 table, new section discussing washout factor added, matches version published in Phys. Rev. D