Mu-tau neutrino refraction and collective three-flavor transformations in supernovae

TL;DR

This paper investigates how three-flavor neutrino transformations in supernovae are affected by mu-tau matter effects, revealing a resonance that significantly alters neutrino survival probabilities depending on mixing parameters.

Contribution

It introduces the impact of the mu-tau matter term on collective neutrino oscillations, highlighting a resonance that modifies flavor survival probabilities in supernovae.

Findings

Identification of a mu-tau matter resonance at high density

Significant modifications to electron neutrino survival probabilities

Sensitivity of effects to deviations from maximal 23-mixing

Abstract

We study three-flavor collective neutrino transformations in the dense-neutrino region above the neutrino sphere of a supernova core. We find that two-flavor conversions driven by the atmospheric mass difference and the 13-mixing angle capture the full effect if one neglects the second-order difference between the muon and tau neutrino refractive index. Including this "mu-tau matter term" provides a resonance at a density of approximately 3 x 10^7 g cm^-3 that typically causes significant modifications of the overall electron neutrino and antineutrino survival probabilities. This effect is surprisingly sensitive to deviations from maximal 23-mixing, being different for each octant.