Neutrino-antineutrino correlations in dense anisotropic media

TL;DR

This paper derives comprehensive evolution equations for neutrino-antineutrino propagation in dense, anisotropic media, highlighting the role of correlations and helicity coherence, with implications for astrophysical phenomena like supernovae.

Contribution

It presents the most general mean-field equations accounting for neutrino-antineutrino mixing, including pair correlations and helicity coherence, in anisotropic environments.

Findings

Correlations are sourced by neutrino and antineutrino densities in anisotropic media.

The equations apply to both Dirac and Majorana neutrinos.

Implications for supernova neutrino physics are discussed.

Abstract

We derive the most general evolution equations describing in-medium (anti)neutrino propagation in the mean-field approximation. In particular, we consider various types of neutrino-antineutrino mixing, for both Dirac and Majorana fields, resulting either from nontrivial pair correlations or from helicity coherence due to the nonvanishing neutrino masses. We show that, unless the medium is spatially homogeneous and isotropic, these correlations are sourced by the usual neutrino and antineutrino densities. This may be of importance in astrophysical environments such as core-collapse supernovae.