Neutrino masses and lepton mixing from A5 and CP

Abstract

We analyse in details the phenomenological implications for lepton masses and mixing due to the breaking of the discrete symmetries A5 and CP into the subgroups Z2×CP and Z5 for the neutrino and charged-lepton sectors. The direct product of Z2 and CP in the neutrino sector allows for a complete determination of masses, mixing and CP phases in terms of only four real parameters. Consequently, we derive accurate analytic expressions for the sum of the neutrino masses as well as the effective Majorana masses, mβ and mββ, under different hypotheses for the flavon vevs. Finally, we compare our predictions with the exact numerical results obtained from the diagonalisation of the neutrino mass matrix and discuss their accuracy.