Supernova neutrino halo and the suppression of self-induced flavor conversion

TL;DR

This paper investigates how a neutrino halo from supernovae affects neutrino flavor conversion, finding that despite the halo's broadening of neutrino angles, matter effects still suppress flavor changes during the accretion phase.

Contribution

It provides a detailed analysis of the supernova neutrino halo's impact on flavor conversion, highlighting the continued suppression by matter effects.

Findings

Neutrino halo dominates at large distances during accretion.

Multiangle matter effects suppress flavor conversion despite the halo.

Halo broadening increases the matter effect's influence.

Abstract

Neutrinos streaming from a supernova (SN) core occasionally scatter in the envelope, producing a small "neutrino halo" with a much broader angle distribution than the primary flux originating directly from the core. Cherry et al. (2012) have recently pointed out that, during the accretion phase, the halo actually dominates neutrino-neutrino refraction at distances exceeding some 100 km. However, the multiangle matter effect (which increases if the angle distribution is broader) still appears to suppress self-induced flavor conversion during the accretion phase.