LARGE NEUTRINO MIXING ANGLES IN UNIFIED THEORIES

Typically in unified theories the neutrino mixing angles, like the Cab ibbo-Kobayashi-Maskawa (CKM) angles of the quarks, are related to the small mass ratios between fermions of different generations and are th erefore quite small. A new approach for explaining the intergeneration al mass hierarchies is proposed here which, while giving small CKM ang les, naturally leads to neutrino angles of order unity. Such large mix ing angles may be required for a resolution of the atmospheric neutrin o anomaly and may also be relevant for the solar neutrino puzzle. The mechanism presented here provides a framework in which novel approache s to the fermion mass question can arise. In particular, within this f ramework a variant of the texture idea allows highly predictive models to be constructed, an illustrative example of which is given. It is s hown how the neutrino mixing angles may be completely determined in su ch schemes.