Maximal CP Violation in Flavor Neutrino Masses

Abstract

Since flavor neutrino masses $M_{\mu\mu,\tau\tau,\mu\tau}$ can be expressed in terms of $M_{ee,e\mu,e\tau}$, mutual dependence among $M_{\mu\mu,\tau\tau,\mu\tau}$ is derived by imposing some constraints on $M_{ee,e\mu,e\tau}$. For appropriately imposed constraints on $M_{ee,e\mu,e\tau}$, we show a texture of neutrino mass matrix giving rise to maximal CP violation. When the atmospheric neutrino mixing is also maximal, we discuss various specific textures of neutrino mass matrices including the texture with $M_{\tau\tau}=M^\ast_{\mu\mu}$ derived as the simplest solution to the constraint of $M_{\tau\tau}-M_{\mu\mu}$=imaginary, which is required by the constraint of $M_{e\mu}\cos\theta_{23}-M_{e\tau}\sin\theta_{23}$=real for $\cos 2\theta_{23}=0$. It is found that Majorana CP violation depends on the phase of $M_{ee}$.