DISCRETE '08: Symposium on Prospects in the Physics of Discrete Symmetries

Embedding discrete symmetries: Large neutrino mixingin SO(10) GUT

11 Dec 2008, 15:50

20m

Valencia, Spain

Family Symmetries Parallel Session B. Family symmetries-I

Speaker

Prof. emilio torrente-lujan (dept. fisica)

Description

We present a common explanation of the fermion mass hierarchy and the large lepton mixing angles in the context of a grand unified flavor and gauge theory (GUTF). Our starting point is a SU(3)xU(1) flavor symmetry and a SO(10) GUT, a basic ingredient of our theory which plays a major role is that two different breaking pattern of the flavor symmetry are at work. On one side, the dynamical breaking of SU(3)xU(1) flavor symmetry into U(2)xZ_3 explains why one family is much heavier than the others. On the other side, an explicit symmetry breaking of SU(3) into a discrete flavor symmetry leads to the observed tribimaximal mixing for the leptons. We write an explicit model where this discrete symmetry group is A4. Naturalness of the charged fermion mass hierarchy appears as a consequence of the continuous SU(3) flavor symmetry. Moreover, the same discrete A4-GUT invariant operators are the root of the large lepton mixing, small Cabibbo angle, and neutrino masses. *based on work made in collaboration: F. Bazzocchi, S. Morisi, M. Picariello, E. Torrente-Lujan