Suppression of Self-Induced Flavor Conversion in the Supernova Accretion Phase

TL;DR

This study analyzes supernova neutrino flavor conversions during the accretion phase, finding that realistic matter and neutrino profiles suppress self-induced conversions, leaving only the MSW effect, which can help determine the neutrino mass hierarchy.

Contribution

It provides a linearized stability analysis with realistic energy and angle distributions, demonstrating suppression of self-induced flavor conversions in supernova conditions.

Findings

Self-induced flavor conversions are suppressed during the accretion phase.

Flavor conversions are limited to the MSW effect under realistic conditions.

The neutrino mass hierarchy can be distinguished if theta_13 is large.

Abstract

Self-induced flavor conversions of supernova (SN) neutrinos can strongly modify the flavor dependent fluxes. We perform a linearized flavor stability analysis with accretion-phase matter profiles of a 15 M_sun spherically symmetric model and corresponding neutrino fluxes. We use realistic energy and angle distributions, the latter deviating strongly from quasi-isotropic emission, thus accounting for both multi-angle and multi-energy effects. For our matter and neutrino density profile we always find stable conditions: flavor conversions are limited to the usual MSW effect. In this case one may distinguish the neutrino mass hierarchy in a SN neutrino signal if the mixing angle theta_13 is as large as suggested by recent experiments.