Sin θ 13 and neutrino mass matrix with an approximate flavor symmetry

Abstract

For a neutrino mass matrix whose texture has an approximate flavor symmetry and where one has near degenerate neutrino mass, it is shown that the tribimaximal values for atmospheric angle sin2 $ {\theta_{{23}}} = \frac{1}{2} $ and solar angle sin2 $ {\theta_{{12}}} = \frac{1}{3} $ can be maintained even when the reactor angle θ 13 ≠ 0. The non zero sin θ 13 implies approximate ν μ → −ν τ symmetry instead of ν μ → ν τ symmetry.