Landau Damping of Collective Neutrino Oscillation Waves

TL;DR

This paper investigates Landau damping in collective neutrino oscillation waves within dense astrophysical environments, finding that damping rates are typically negligible, thus not hindering flavor conversions crucial for supernovae and neutron star mergers.

Contribution

It demonstrates that Landau damping rates of fast neutrino oscillation modes are generally very small and vanish in the pure fast limit, clarifying their impact on flavor conversions.

Findings

Damping rates are usually very small.

Damping vanishes in the pure fast limit.

Unstable modes driving flavor conversions are unaffected.

Abstract

Dense neutrino media in core-collapse supernovae and neutron star mergers can experience collective flavor transformations in the form of neutrino oscillation waves. It was recently reported that the stable fast modes of collective oscillations can be damped through a mechanism similar to the Landau damping of plasma waves. In this work, we show that the actual damping rates of fast oscillation waves are usually very small and vanishes in the pure fast limit. This result does not affect the unstable modes that eventually drive collective neutrino flavor conversions in supernovae and neutron star mergers.