S_4 Flavored CP Symmetry for Neutrinos
  A generalized CP symmetry for leptons is presented where CP transformations are part of an $S_4$ symmetry that connects different families. We study its implications for lepton mixings in a gauge model realization of the idea using type II seesaw for neutrino masses. The model predicts maximal atmospheric mixing, nonzero $\theta_{13}$ and maximal Dirac phase $\delta_{D}= \pm\pi/2$. 
R. N. Mohapatra, C. C. Nishi
hep-ph