Collective neutrinos oscillation in matter and CP-violation

TL;DR

This paper investigates how CP violation influences neutrino oscillations in dense astrophysical environments, revealing that flux differences between muon and tau neutrinos can lead to CP-dependent effects in electron neutrino fluxes.

Contribution

It demonstrates that CP violation effects become significant in supernova neutrino oscillations when muon and tau neutrino fluxes differ, highlighting the role of non-linear evolution equations.

Findings

Electron neutrino fluxes are insensitive to CP phase if muon and tau neutrinos interact similarly.

Differences in muon and tau neutrino fluxes induce CP-dependent oscillation features.

Radiative corrections can also induce CP effects in neutrino refractive index.

Abstract

We explore CP violation effects on the neutrino propagation in dense environments, such as in core-collapse supernovae, where the neutrino self-interaction induces non-linear evolution equations. We demonstrate that the electron (anti)neutrino fluxes are not sensitive to the CP violating phase if the muon and tau neutrinos interact similarly with matter. On the other hand, we numerically show that new features arise, because of the non-linearity and the flux dependence of the evolution equations, when the muon and tau neutrinos have different fluxes at the neutrinosphere (due to loop corrections or of physics beyond the Standard Model). In particular, the electron (anti)neutrino probabilities and fluxes depend upon the CP violating phase. We also discuss the CP effects induced by radiative corrections to the neutrino refractive index.