Neutrino damping rate at finite temperature and density

TL;DR

This paper derives the neutrino damping rate at finite temperature and density using thermal field theory, providing explicit formulas and analyzing the relation between damping and scattering in a medium of particles.

Contribution

It offers a first-principles derivation of neutrino damping rates at finite temperature and density, connecting thermal field theory with scattering amplitude approaches.

Findings

Explicit formulas for neutrino damping rate in various media.

Relation between damping rate and forward scattering amplitude.

Analysis of neutrino dispersion relation in thermal environments.

Abstract

A first principle derivation is given of the neutrino damping rate in real-time thermal field theory. Starting from the discontinuity of the neutrino self energy at the two loop level, the damping rate can be expressed as integrals over space phase of amplitudes squared, weighted with statistical factors that account for the possibility of particle absorption or emission from the medium. Specific results for a background composed of neutrinos, leptons, protons and neutrons are given. Additionally, for the real part of the dispersion relation we discuss the relation between the results obtained from the thermal field theory, and those obtained by the thermal average of the forward scattering amplitude.