U(2)-like flavor symmetries and approximate bimaximal neutrino mixing

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Abstract
Models involving a U(2) flavor symmetry, or any of a number of its non-Abelian discrete subgroups, can explain the observed hierarchy of charged fermion masses and Cabibbo-Kobayashi-Maskawa angles. It is known that a large neutrino mixing angle connecting second and third generation fields may arise via the seesaw mechanism in these models, without a fine-tuning of the parameters. Here we show that it is possible to obtain approximate bimaximal mixing in a class of models with U(2)-like Yukawa textures. We find a minimal form for Dirac and Majorana neutrino mass matrices that leads to two large mixing angles, and show that our result can quantitatively explain atmospheric neutrino oscillations while accommodating the favored, large-angle Mikheyev-Smirnov-Wolfenstein solution to the solar neutrino problem. We demonstrate that these textures can arise in models by presenting a number of explicit examples.