Update on two-zero textures of the Majorana neutrino mass matrix in light of recent T2K, Super-Kamiokande and NO$\nu$A results

Abstract

The latest results from atmospheric and accelerator neutrino experiments indicate that the normal neutrino mass ordering $m^{}_1 < m^{}_2 < m^{}_3$, a maximal leptonic CP-violating phase $\delta = 270^\circ$ and the second octant of neutrino mixing angle $\theta^{}_{23} > 45^\circ$ are favored. In light of new experimental results, we update previous phenomenological studies on two-zero textures of the Majorana neutrino mass matrix $M^{}_\nu$, in the flavor basis where the charged-lepton mass matrix $M^{}_l$ is diagonal. When the $1\sigma$ ranges of neutrino mixing parameters are taken into account, only four (i.e., ${\bf A}^{}_{1, 2}$ and ${\bf B}^{}_{2,4}$) among seven two-zero patterns of $M^{}_\nu$ show the aforementioned features of neutrino mass spectrum, mixing angle $\theta^{}_{23}$ and CP-violating phase $\delta$, and thus are compatible with the latest neutrino oscillation data. The correlative relations among neutrino masses and mixing parameters have been derived analytically for these four patterns, and the allowed regions of neutrino mixing angles and the CP-violating phase are also given. Possible realizations of four viable two-zero textures via non-Abelian discrete flavor symmetries are discussed.