The effect of Majorana phase in degenerate neutrinos

TL;DR

This paper investigates how the Majorana phase influences the stability of maximal neutrino flavor mixing under quantum corrections, especially in degenerate neutrino mass scenarios.

Contribution

It reveals the critical role of the Majorana phase in maintaining maximal mixing stability against quantum corrections in degenerate neutrino cases.

Findings

Majorana phase of π stabilizes maximal mixing against quantum corrections.

Majorana phase of zero spoils maximal mixing with O(eV) degenerate masses.

Large mass hierarchy prevents quantum correction effects on mixing.

Abstract

There are physical Majorana phases in the lepton flavor mixing matrix when neutrinos are Majorana fermions. In the case of two degenerate neutrinos, the physical Majorana phase plays the crucial role for the stability of the maximal flavor mixing between the second and the third generations against quantum corrections. The physical Majorana phase of $\pi$ guarantees the maximal mixing to be stable against quantum corrections, while the Majorana phase of zero lets the maximal mixing be spoiled by quantum corrections when neutrino masses are of O(eV). The continuous change of the Majorana phase from $\pi$ to 0 makes the maximal mixing be spoiled by quantum corrections with O(eV) degenerate neutrino masses. On the other hand, when there is the large mass hierarchy between neutrinos, the maximal flavor mixing is not spoiled by quantum corrections independently of the Majorana phase.