Realistic Tri-Bi-Maximal neutrino mixing

Abstract

We propose a generalized version of the Tri-Bi-Maximal (TBM) ansatz for lepton mixing, leading to non-zero reactor angle $\theta_{13}$ and CP violation. The latter is characterized by two CP phases. The Dirac phase affecting neutrino oscillations is nearly maximal ($\delta_{CP} \sim \pm \pi/2$), while the Majorana phase implies narrow allowed ranges for the neutrinoless double beta decay amplitude. The solar angle $\theta_{12}$ lies nearly at its TBM value, while the atmospheric angle $\theta_{23}$ has the TBM value for maximal $\delta_{CP}$. Neutrino oscillation predictions can be tested in present and upcoming experiments.