CPV predictions from flavour symmetries

In the reference 3-neutrino mixing scheme leptonic CP violation can be caused by the Dirac, δ, and/or Majorana, α21 and α31, CP-violating phases present in the unitary neutrino mixing matrix U. Using the fact that U=U†eUν, Ue and Uν being unitary matrices diagonalising the charged lepton and neutrino mass matrices, respectively, we consider in a systematic way forms of Ue and Uν allowing us to derive sum rules for cosδ, α21 and α31, i.e., to express them in terms of the measured neutrino mixing angles present in U and the angles (and phases in the case of sum rules for α21 and α31) contained in Uν, whose values are fixed by a discrete flavour symmetry (a generalised CP symmetry). We consider several concrete forms of Uν, including the bimaximal, tri-bimaximal and golden ratio mixing forms. For each of these forms and forms of Ue allowing to reproduce the measured values of the neutrino mixing angles, we obtain numerical predictions for δ, α21 and α31. Using the obtained values of the CP-violating phases, we present predictions for the effective Majorana mass in neutrinoless double beta decay.