QUANTUM CORRECTIONS TO NEUTRINO MASSES AND MIXING ANGLES

Abstract

Neutrino masses originate most likely at some high energy scale M≫MZ. To obtain reliable predictions for neutrino masses and mixing angles one has to take into account quantum corrections which, in cases of degenerate or partly degenerate neutrino spectra, can significantly change the pattern of the mixing angles. We review the calculation of these quantum corrections in the case in which the neutrino masses are effectively described by the single dimension 5 operator. In the framework of the Standard Model or its minimal supersymmetric extension we discuss both the corrections described by the renormalization group equations (RGE) and the low energy threshold corrections. We emphasize that the infrared fixed points of the RGE predict a relation between the mixing angles which is incompatible with the presently favoured LMA solution to the solar neutrino problem. We also show that in the MSSM the threshold corrections can lead to qualitatively different predictions for the mixing angles.