Majorana phases in neutrino-antineutrino oscillations

TL;DR

This paper explores CP violation in neutrino-antineutrino oscillations for Majorana neutrinos, highlighting how these processes can reveal Majorana phases beyond neutrinoless double beta decay experiments.

Contribution

It systematically analyzes CP violation in neutrino-antineutrino oscillations, identifying key parameters and asymmetries that can inform on Majorana phases.

Findings

Identification of six CP-conserving mass terms

Nine Jarlskog-like parameters for CP violation

Illustration of CP asymmetries using current data

Abstract

If the massive neutrinos are Majorana particles, neutrinoless double beta ($0\nu\beta\beta$) decay experiments are not enough to determine the Majorana phases. We carry out a systematic study of CP violation in neutrino-antineutrino oscillations. In these processes, CP-conserving parts involve six independent $0\nu\beta\beta$-like mass terms $\langle m\rangle_{\alpha\beta}$ and CP-violating parts are associated with nine independent Jarlskog-like parameters ${\cal V}^{ij}_{\alpha\beta}$ (for $\alpha, \beta = e, \mu, \tau$ and $i, j = 1, 2,3$). With the help of current neutrino oscillation data, we illustrate the salient features of six independent CP-violating asymmetries between $\nu_\alpha \to \bar{\nu}_\beta$ and $\bar{\nu}_\alpha \to \nu_\beta$ oscillations.