SESZIONE DI TORINO
Discrete flavour symmetry A4 explain very well neutrino data at low energy, but it seems difficult to extend it to SO(10) grand unified model since, in most of the models, left-handed and right-handed fields belongs to different representations of A4. Recently a model has been proposed by E.Ma where all fermions transform equally under A4. We study a SO(10)xA4 realization of such a model with type-I seesaw dominance which preserves tribimaximal leptonic mixing. Charged fermion mass hierarchies are fitted, however we assume quark mixing angles to be zero. By embedding A4 into left-right flavour symmetry it is possible to predict heavy 3rd family, tribimaximal mixing and we suggest a possible origin of Cabibbo angle in quark sector.

DATA: 05-02-2008