Neutrino flavor dynamics in post-bounce supernovae: the role of the electron component

Abstract

In this paper we study the dynamics of flavor transformation for neutrinos propagating in the very dense environment of astrophysical compact objects as Type II supernova in post collapse phase and proto-neutron stars. The analysis is based on the generalized Boltzmann equation, which incorporates the neutrinoneutrino interaction. We focus the analysis on the possible collective flavor dynamics, which can displays bipolar and synchronized flavor oscillations, and the associated transition from single-angle to multi-angle regime. To solve the kinetic equations we use an expansion in Legendre polynomials and a two-flavor scheme. On the basis of the numerical simulations we argue that neutrino flavor dynamics is suppressed by the presence of the electron component up to a certain distance from the neutrino sphere, where a transition to multi-angle regime occurs. This distance will move towards the neutrino sphere as the neutrino emission epoch proceeds.