Large CP Violation, Large Mixings of Neutrinos and Democratic-type Neutrino Mass Matrix

Abstract

We propose a democratic-type neutrino mass matrix based on $Z_3$ symmetry. This mass matrix predicts the CP violation phase, $\delta =\pi /2$, and the mixing angle between the mass eigenstates ${\nu }_2$ and ${\nu }_3$, ${\sin }^2{\theta }_{23}={\cos }^2{\theta }_{23}=1/2$ which is essential for the large atmospheric neutrino mixing, between ${\nu }_{\mu }$ and ${\nu }_{\tau }$. In this model, the large CP violation effect may be expected.

Comments: LaTeX, 22pages, corrected some terminologies, reference added