FERMIONIC MASS MATRICES WITH LARGE NEUTRINO MIXING IN A GUT SCENARIO

We present a GUT scenario which can reproduce the observed regularities and irregularities in the spectrum of the fermionic masses and mixings. All mass matrices are proportional to each other on the tree level. Radiative corrections, induced via superheavy neutral leptons, generate the mixings and explain the diversity in the mass spectra of the different flavors. In particular, mu and me are naturally small. The leptonic mass matrices are dictated by the quark sector. They give large neutrino mixings in a way that enables us to solve the solar neutrino puzzle in terms of vacuum oscillations, without coming in conflict with the observations of neutrinos from supernova 1987a. The quark mixings, on the other hand, are automatically small, without the need for fine tuning of mass ratios. CP violation is generated at GUT energies, so th0t it can trigger the baryon asymmetry in the universe. The same phase is carried down to the low energy K0-decay, via the radiative corrections. © 1990.