Neutrino Mixings and Fermion Masses in Supersymmetric SU(5)

Abstract

We consider neutrino mixings in supersymmetric SU(5) supplemented by a U(1) flavor symmetry. In particular, we show how bi-maximal neutrino mixings can be realized. Two scenarios for implementing the small mixing angle MSW solution, with one involving a sterile state ${\nu }_s$ and maximal ${\nu }_{\mu }-{\nu }_s$ mixing to resolve the atmospheric anomaly, are also discussed. Finally, a new mechanism for eliminating the asymptotic relations $m_{\mu }^{(0)}=m_s^{(0)}$ and $m_e^{(0)}=m_d^{(0)}$, while retaining $m_{\tau }^{(0)}=m_b^{(0)}$, is presented. It employs `matter' multiplets in the $15+\overline{15}$ of SU(5), and is consistent with the various oscillation scenarios, as well as with the unification at $M_{GUT}$ of the three gauge couplings.

Comments: 11 pp, LATEX. Typos are corrected, accepted for Phys. Lett. B