Fermion Masses and Neutrino Oscillations in SO(10) SUSY GUT with D_3 x U(1) Family Symmetry

Abstract

Discrete nonabelian gauge symmetries appear to be the most advantageous candidates for a family symmetry. We present a predictive SO(10) SUSY GUT model with $D_3 \times U(1)$ family symmetry (D_3 is the dihedral group of order 6). The hierarchy in fermion masses is generated by the family symmetry breaking $D_3 \times U(1) \to Z_N \to $ nothing. This model fits the low energy data in the charged fermion sector quite well and naturally provides large angle $\nu_{\mu}$-$\nu_{\tau}$ mixing describing atmospheric neutrino oscillation data and small angle $\nu_e$-$\nu_s$ mixing consistent with the small mixing angle MSW solution to the solar neutrino data. In addition, the non-abelian family symmetry D_3 is sufficient to suppress large flavor violations.