Grand unification of $μ-τ$ Symmetry

Abstract

Near maximal neutrino mixing needed to understand atmospheric neutrino data can be interpreted to be a consequence of an interchange symmetry between the muon and tau neutrinos in the neutrino mass matrix in the flavor basis. This idea can be tested by a measurement of the neutrino mixing parameter $θ_{13}$ and looking for its correlation with $θ_{23}-π/4$. We present a supersymmetric SU(5) grand unified model for quarks and leptons which obeys this exchange symmetry and is a realistic model that can fit all observations. GUT embedding shifts $θ_{13}$ from its zero $μ-τ$ symmetric value to a nonzero value keeping it under an upper limit.

13 pages and 4 figures