Muon-Tau Symmetry and Leptogenesis in the Minimal Seesaw Model

Abstract

The measured values for the mixture angles in neutrino oscillations suggest the existence of a symmetry of interchange of flavor between muon and tau neutrinos. Using this symmetry we analyzed the minimal seesaw model for neutrino masses, where the Majorana mass was diagonalized, and it is demonstrated that the model supports at most 3 CP violation phases and 5 real masses at high energies. Nevertheless, at low energies, only 4 parameters of mass and one relative Majorana CP phase remain. Therefore using the experimental values of the masses square differences, the mixture angles and the hierarchy, we can determine some parameters of the model but not all. Also we propose the use of the parameter of baryonic asymmetry of the universe due to leptogenesis to determine one more phase of the model. Finally we used a normal hierarchy for the masses of the right handed neutrinos to make an approximation, that allowed us to completely reconstruct the mass matrix for left handed neutrinos. In special the value of mee is determined which can be compared with the results of the neutrinoless double decay beta.Comment: This is a thesis written to obtain a Master in Science degree, made under the advise of Abdel Perez Lorenzana, Ph