CP-violation in oscillations of three neutrino generations: the case of degenerate masses

TL;DR

This paper investigates how CP-violation in neutrino oscillations is affected by degenerate neutrino masses and explores mechanisms for restoring CP-violation when two neutrino masses are degenerate.

Contribution

It demonstrates different mechanisms by which CP-violation can be recovered in the case of two degenerate neutrino mass states.

Findings

CP-violation vanishes when two neutrino masses are degenerate

Mechanisms for CP-violation recovery are identified and demonstrated

The role of the complex phase in the PMNS matrix is analyzed

Abstract

CP-symmetry violates in oscillations of neutrinos in vacuum in presence of three generations. In this case there is an inherent complex phase in PMNS-matrix. When any two neutrino masses degenerate the CP-violation vanishes. In the present article different mechanisms of CP-symmetry recovery are demonstrated in case of two degenerate neutrino mass-states.