Intrinsic deviation from the tri-bimaximal neutrino mixing in a class of A 4 flavor models

摘要

It is well known that the tri-bimaximal neutrino mixing patternV0can be derived from a class of flavor models with the non-AbelianA4symmetry. We point out that small corrections toV0, which are inherent in theA4models and arise from both the charged-lepton and neutrino sectors, have been omitted in the previous works. We show that such corrections may lead the3×3neutrino mixing matrixVto a non-unitary deviation fromV0, but they cannot result in a nonzero value ofθ13or any new CP-violating phases. Current experimental constraints on the unitarity ofVallow us to constrain the model parameters to some extent.