Fermion Masses, Neutrino Oscillations and SUSY Grand Unification

The origin of fermion masses and mixing remains a puzzle in particle physics. In this talk, I will describe how the number of parameters in the Yukawa sector that parameterized all fermion masses and mixing angles can be reduced by imposing symmetries, and argue why small neutrino masses and their large mixing are closely connected to the unification of the strong, weak and electromagnetic forces. This is demonstrated in a specific model based on SUSY SO(10) combined with an SU(2) family symmetry in which a set of symmetric matrices with five texture-zeros (having eleven parameters) can lead to values of twenty-two measurable masses and mixing angles of quarks and leptons; the available experimental data is in agreement in atmospheric and solar neutrino cases, leaving the predicted masses of neutrinos and some lepton mixing angles to be verified by future experiments. The predictions for the branching ratios of the lepton flavor violating charged lepton decays in this model are accessible to the next generation of experiments. Current status of the theoretical predictions for proton decay will also be reviewed. Finally, I will delineate a possible connection between neutrino oscillations and the baryon asymmetry of the Universe.