Tribimaximal Mixing From Small Groups

TL;DR

This paper systematically explores small finite groups capable of producing tribimaximal neutrino mixing, identifying specific groups like T7 and T13 as promising candidates, and presents a model consistent with recent experimental hints of non-zero theta13.

Contribution

It provides a comprehensive scan of 76 flavor groups, identifying those compatible with tribimaximal mixing and proposing a new model with testable predictions for neutrino mixing angles.

Findings

44 groups can accommodate models consistent with experiment at 3 sigma

38 groups can produce tribimaximal mixing

A specific model predicts theta13=5.1 degrees, testable soon

Abstract

Current experimental data on the neutrino parameters is in good agreement with tribimaximal mixing and may indicate the presence of an underlying family symmetry. For 76 flavor groups, we perform a systematic scan for models: The particle content is that of the Standard Model plus up to three flavon fields, and the effective Lagrangian contains all terms of mass dimension <=6. We find that 44 groups can accommodate models that are consistent with experiment at 3 sigma, and 38 groups can have models that are tribimaximal. For one particular group, we look at correlations between the mixing angles and make a prediction for theta13 that will be testable in the near future. We present the details of a model with theta12=33.9, theta23=40.9, theta13=5.1 to show that the recent tentative hints of a non-zero theta13 can easily be accommodated. The smallest group for which we find tribimaximal mixing is T7. We argue that T7 and T13 are as suited to produce tribimaximal mixing as A4 and should therefore be considered on equal footing. In the appendices, we present some new mathematical methods and results that may prove useful for future model building efforts.