Nonzeroθ13signals nonmaximal atmospheric neutrino mixing

Abstract

From recent groundbreaking experiments, it is now known that the Pontecorvo-Maki-Nakagawa-Sakata mixing differs significantly from the tribimaximal model in which ${\ensuremath{\theta}}_{13}=0$ and ${\ensuremath{\theta}}_{23}=\ensuremath{\pi}/4$. Flavor symmetry can require that the departures from these two equations are linearly related. ${T}^{\ensuremath{'}}$ and ${A}_{4}$, which successfully accommodated the pre-T2K Pontecorvo-Maki-Nakagawa-Sakata matrix, predict that $38.07\ifmmode^\circ\else\textdegree\fi{}\ensuremath{\le}{\ensuremath{\theta}}_{23}\ensuremath{\le}39.52\ifmmode^\circ\else\textdegree\fi{}$ at 95% C.L. The best fit values, combining the model predictions with T2K, MINOS, Double Chooz, Daya Bay, and RENO data, are ${\ensuremath{\theta}}_{23}=38.7\ifmmode^\circ\else\textdegree\fi{}$ and ${\ensuremath{\theta}}_{13}=8.9\ifmmode^\circ\else\textdegree\fi{}$.