A supersymmetric S4 x CP model for leptons - all in one: maximal CP violation, maximal theta_{23} and small theta_{13}

by Dr Claudia Hagedorn (University of Padua)

Tuesday 11 Jun 2013, 14:00 → 15:00 Europe/Paris

Room 149, Batiment 1

I will discuss a supersymmetric model for leptons with the flavour symmetry S4 x Z3 and a CP symmetry. These symmetries are broken in a non-trivial way such that the neutrino sector is invariant under Z2 x CP and the charged lepton one under Z3^(D), which is the diagonal subgroup of a Z3 subgroup of S4 and the external Z3 factor. Lepton mixing angles and Dirac as well as Majorana phases are predicted in terms of a single parameter. This parameter is directly related to the reactor mixing angle and is naturally of the correct size in this model. Furthermore, the atmospheric mixing angle and the Dirac phase are both maximal, while the two Majorana phases are trivial. The solar mixing angle is constrained by sin^2 theta_{12} >= 1/3. Since neutrino masses depend effectively only on two real parameters at leading order, they have to be normally ordered and the absolute neutrino mass scale and the sum of neutrino masses are predicted. The hierarchy among the charged lepton masses is correctly reproduced without tuning. The vacuum alignment and subleading corrections are studied in detail and the latter are in general small.