Cobimaximal Neutrino Mixing from $A_4$ and its Possible Deviation

Abstract

It has recently been shown that the phenomenologically successful pattern of cobimaximal neutrino mixing (${\theta }_{13}\ne 0$, ${\theta }_{23}=\pi /4$, and ${\delta }_{CP}=\pm \pi /2$) may be achieved in the context of the non-Abelian discrete symmetry $A_4$, if the neutrino mass matrix is diagonalized by an orthogonal matrix $\mathcal{O}$. We study how this pattern would deviate if $\mathcal{O}$ is replaced by an unitary matrix.

Comments: 10 pages, no figure