A Scan for Models of Neutrino Mixing from Non-Abelian Discrete Symmetries

Abstract

The structure of the neutrino mixing matrix is indicative of an underlying family symmetry that interrelates the three generations of fermions in the Standard Model. We systematically scan the parameter space of 76 discrete non-Abelian family symmetries and construct all models with the Standard Model particle content and up to three flavon fields where we include non-renormalizable interactions of mass dimension five and six. We find that of the 76 groups that we considered, 44 groups can accommodate models that are consistent with experiment at 3sigma, and 38 groups can have models that are tribimaximal. One immediate consequence is that A4 is not "special", but should be considered on equal footing with other groups such as T7 that is the smallest group for which we find tribimaximal mixing, and T13 that has the largest fraction of TBM models. We present the details of a model with theta12=33.9, theta23=49.1, theta13=5.1 to show that a non-zero theta13 can easily be accommodated.Comment: Contribution to the proceedings of "The 2011 Europhysics Conference on High Energy Physics-HEP 2011", July 21-27, 2011, Grenoble, Franc