Multiple Spectral Splits of Supernova Neutrinos

TL;DR

This paper explores the complex phenomena of spectral swaps and splits in supernova neutrino oscillations, revealing their general occurrence across different hierarchies and conditions, and analyzing their stability and features.

Contribution

It demonstrates that multiple spectral splits are common in supernova neutrino oscillations, extending previous understanding to both hierarchies and various spectral conditions.

Findings

Spectral swaps occur around spectral crossings and infinite energies.

Multiple swaps and splits are typical in both hierarchies.

Splits can remain sharp despite decoherence effects.

Abstract

Collective oscillations of supernova neutrinos swap the electron neutrino and antineutrino spectra with those of another flavor in certain energy intervals bounded by sharp spectral splits. This phenomenon is far more general than previously appreciated: typically one finds one or more swaps and accompanying splits in the neutrino and antineutrino channels for both inverted and normal neutrino mass hierarchies. Depending on an instability condition, swaps develop around spectral crossings (energies where the electron neutrino or antineutrino fluxes are equal to that of another flavor, as well as infinite E where all fluxes vanish), and the widths of swaps are determined by the spectra and fluxes. Wash-out by multi-angle decoherence varies across the spectrum and splits can survive as sharp spectral features.