Trimaximal mixing with predicted θ13 from a new type of constrained sequential dominance

Following the recent T2K indication of a sizeable reactor angle, we present a class of models which fix theta(13) while preserving trimaximal solar mixing. The models are based on a new type of constrained sequential dominance involving new vacuum alignments, along the (1, 2, 0)(T) or (1, 0, 2)(T) directions in flavour space. We show that such alignments are easily achieved using orthogonality, and may replace the role of the subdominant flavon alignment (1, 1, 1)(T) in constrained sequential dominance. In such models, with a normal hierarchical spectrum, the reactor angle is related to a ratio of neutrino masses by theta(13) = root 2/3 m(2)(nu)/m(3)(nu), leading to theta(13) similar to 5 degrees-6 degrees, while the atmospheric angle is given by the sum rule theta(23) approximate to 45 degrees + root 2 theta(13) cos delta. We find that leptogenesis is unsuppressed due to the violation of form dominance and that the CP violating phase responsible for leptogenesis is precisely equal to the Dirac CP phase delta, providing a direct link between leptogenesis and neutrino mixing in this class of models. (C) 2011 Elsevier B.V. All rights reserved.