Pauli blocking: probing beyond-mean-field effects in neutrino flavor evolution

TL;DR

This paper investigates how beyond-mean-field effects, specifically neutrino degeneracy, influence neutrino flavor evolution in dense astrophysical environments, revealing shifts in stability regions and potential suppression or emergence of flavor instabilities.

Contribution

It heuristically explores the impact of beyond-mean-field effects on neutrino flavor stability, highlighting limitations of the mean-field approximation in dense environments.

Findings

Degeneracy effects can damp flavor conversion in some cases.

Angular distributions can become unstable beyond mean-field predictions.

Stability regions are shifted by beyond-mean-field corrections.

Abstract

Neutrino quantum kinetics in dense astrophysical environments is investigated relying on the mean-field approximation. In this paper, we heuristically explore whether beyond-mean-field effects due to neutrino degeneracy could hinder flavor instabilities that are otherwise foreseen. Our results show that these corrections shift the stability regions for a suite of (anti)neutrino ensembles: the flavor conversion of previously unstable distributions can be damped, but angular distributions that are stable in the mean-field case can also become unstable. Our work should serve as a motivation to further investigate the limitations of the mean-field treatment.