Masses and mixing of neutral leptons in a grand unified E6 model with intermediate pati-salam symmetry

Abstract

A brief review of the assignment of elementary fermions and bosons to irreducible multiplets in grand unified models is followed by a discussion of different, hierarchical symmetry breaking chains from down to . We concentrate here on a model with an intermediate Pati-Salam symmetry for which is conserved. In particular, the mass/mixing matrix of electrically neutral fermions (i.e.neutrinos) that would be derived from Yukawa couplings is constructed. The pattern of neutrino masses and some bounds on mixing parameters are discussed.