Minimal lepton flavour structures lead to non-maximal 2-3 mixing

Abstract

Present data prefer a large but non-maximal 2-3 mixing in the lepton sector. We argue that this value, in connection with $\sin {\theta }_{13}\simeq 0.15$, is the generic outcome of minimal flavour structures. We present a few different incarnations of this statement, in terms of lepton mass matrices depending on a small number of parameters, that can be justified by discrete flavour symmetries. We also propose a general procedure to study the correlation between ${\theta }_{23}$, the absolute scale and ordering of the neutrino masses, and the leptonic CP-violating phases.

Comments: 24 pages, 10 figures