Density Fluctuation Effects on Collective Neutrino Oscillations in O-Ne-Mg Core-Collapse Supernovae

TL;DR

This study uses detailed simulations to examine how matter density fluctuations in O-Ne-Mg core-collapse supernovae influence neutrino flavor oscillations, revealing complex effects on neutrino survival probabilities and implications for supernova neutrino detection.

Contribution

It provides the first full multi-angle, 3-flavor simulation analysis of matter density fluctuation effects on neutrino oscillations in supernovae, highlighting the impact of density bumps on neutrino survival.

Findings

Density bumps can increase electron neutrino survival probability.

Matter fluctuations complicate supernova neutrino burst signals.

Neutrino self-coupling and fluctuations can raise low-energy neutrino survival.

Abstract

We investigate the effect of matter density fluctuations on supernova collective neutrino flavor oscillations. In particular, we use full multi-angle, 3-flavor, self-consistent simulations of the evolution of the neutrino flavor field in the envelope of an O-Ne-Mg core collapse supernova at shock break-out (neutrino neutronization burst) to study the effect of the matter density "bump" left by the He-burning shell. We find a seemingly counterintuitive increase in the overall electron neutrino survival probability created by this matter density feature. We discuss this behavior in terms of the interplay between the matter density profile and neutrino collective effects. While our results give new insights into this interplay, they also suggest an immediate consequence for supernova neutrino burst detection: it will be difficult to use a burst signal to extract information on fossil burning shells or other fluctuations of this scale in the matter density profile. Consistent with previous studies, our results also show that the interplay of neutrino self-coupling and matter fluctuation could cause a significant increase in the electron neutrino survival probability at very low energy