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We study a class of models for neutrino mass matrix in Type-II seesaw with A 4 family symmetry. The resulting neutrino mass matrix can be naturally made to respect a μ – τ exchange plus CP conjugate symmetry (GLS) with the CP violating phase δ and the mixing angle θ 23 predicted to be ± π / 2 and π / 4 , respectively. When GLS is explicitly broken by complex Yukawa couplings, the model predictions for δ and θ 23 can be significantly modified. Should future experiments indeed determine θ 23 and δ CP away from the GLS limit values, one then had to consider models with broken GLS. We study several simple scenarios to show how the modifications arise w̱hen GLS is broken and how future experiments can test this class of models. [ABSTRACT FROM AUTHOR]

Abstract: We carry out a U-spin symmetry analysis for CP violation in decays into three light , , and mesons. We clarify some subtle points in constructing decay amplitudes with formed by the two negatively charged light mesons in the final states. U-spin conserving momentum independent and momentum dependent decay amplitudes, and U-spin violating decay amplitudes due to quark mass difference are constructed. [Copyright &y& Elsevier]