Three flavor neutrino conversions in supernovae: Slow $\&$ Fast instabilities

TL;DR

This paper presents the first linear stability analysis of three-flavor neutrino fast instabilities in supernovae, revealing new dynamics and potential influences on flavor conversion growth rates compared to two-flavor models.

Contribution

It introduces a novel linearized approach to study three-flavor fast neutrino instabilities, expanding understanding beyond the traditional two-flavor framework.

Findings

Fast modes grow at the neutrino-neutrino interaction scale, independent of neutrino mass.

Three-flavor effects can alter the growth rates of flavor instabilities.

Qualitative agreement with previous three-flavor nonlinear studies for slow oscillations.

Abstract

Self induced neutrino flavor conversions in the dense regions of stellar core collapse are almost exclusively studied in the standard two flavor scenario. Linear stability analysis has been successfully used to understand these flavor conversions. This is the first linearized study of $\textit{three flavor}$ fast instabilities. The `fast' conversions are fascinating distinctions of the dense neutrino systems. In the fast modes the collective oscillation dynamics are independent of the neutrino mass, growing at the scale of the large neutrino-neutrino interaction strength ($10^5$ km$^{-1}$) of the dense core. This is extremely fast, in comparison to the usual `slow' collective modes driven by much smaller vacuum oscillation frequencies ($10^0$ km$^{-1}$). The three flavor analysis shows distinctive characteristics for both the slow and the fast conversions. The slow oscillation results are in qualitative agreement with the existing nonlinear three flavor studies. For the fast modes, addition of the third flavor opens up possibilities of influencing the growth rates of flavor instabilities when compared to a two flavor scenario.