Relating neutrino masses and mixings by discrete symmetries

Lepton mixing can originate from the breaking of a flavor symmetry in different ways in the neutrino and the charged lepton sector. We propose an extension of this framework that allows us to connect the mixing parameters with masses and, more precisely, with certain types of degeneracy of the neutrino mass spectrum. We obtain relations between the mixing parameters for the cases of partial degeneracy, m(1) = m(2), and complete degeneracy, m(1) = m(2) = m(3). These relations determine also the Majorana phases. It is shown that relatively small corrections to these lowest-order results can produce the required mass splitting and modify the mixing without significant changes of the other symmetry results.