Vacuum oscillations of quasi degenerate solar neutrinos

TL;DR

This paper explores how nearly degenerate neutrino masses can explain solar and atmospheric neutrino oscillations, emphasizing the role of symmetries in maintaining degeneracy and the implications for neutrino mixing angles.

Contribution

It demonstrates that neutrino mass matrices from symmetries can sustain high degeneracy despite radiative corrections, constraining mixing angles near bi-maximal values.

Findings

Degenerate neutrino spectra can explain solar and atmospheric oscillations.

Symmetry-generated mass matrices preserve degeneracy against radiative corrections.

Mixing angles are constrained to be close to bi-maximal.

Abstract

The atmospheric neutrino oscillations and the vacuum oscillation solution of the solar neutrino problem can be consistently described by a doubly or triply degenerate neutrino spectrum as long as the high level of degeneracy required is not spoiled by radiative corrections. We show that this is the case for neutrino mass matrices generated by symmetries. This imposes a strong constraint on the mixing angles and requires the mixing should be close to bi-maximal. We briefly discuss the relevance of our results for the measurability of the neutrino spectrum.