SO(3) Gauge model for neutrino masses and oscillations

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 νμ and ντ 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 νe and νμ 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. ∗Supported in part by Outstanding Young Scientist Research Fund of China, under grant No. of NSF of China: 19625514.