PROTON DECAY AND NEUTRINO MASSES IN SO(10)

In the last few years physicists have been looking at SO(10) GUT models with renewed attention because it has been realized that the SU(5) minimal model cannot unify the strong, electromagnetic and weak interactions in a way consistent with the experimental values of alpha(M(Z)), sin2theta(w)(M(Z)) and alpha(S)(M(Z)). In this paper we derive lower limits on neutrino masses, relevant for cosmology and for the solar-neutrino problem, from necessary consistency conditions on a class of SO(10) models with SU(4)ps x SU(2)L x SU(2)R or SU(3)c x SU(2)L x SU(2)R x U(1)B-L intermediate gauge symmetry.