SO(3) gauge model for neutrino masses and oscillations

Abstract

I mainly describe neutrino masses and oscillations in the gauge model with SO(3) F lepton flavor symmetry and with two Higgs triplets. It is shown how the maximal mixing between v μ and v τ neutrinos comes out naturally after spontaneous breaking of the symmetry. The nearly two-flavor mixing scenario is resulted naturally from an approximate permutation symmetry between the two Higgs triplets. The hierarchy between the neutrino mass-squared differences, which is needed for reconciling both solar and atmospheric neutrino data, leads to an almost maximal mixing between v e and v μ neutrinos. Thus the model favors the intriguing bi-maximal mixing scenario. The three Majorana neutrino masses are allowed to be nearly degenerate and large enough to play a significant cosmological role. The model can also lead to interesting phenomena on lepton-flavor violations via the SO(3) F gauge interactions.