Thermal effects on neutrino-nucleus inelastic scattering in stellar environments

TL;DR

This paper investigates how finite temperature effects influence neutrino inelastic scattering on nuclei in stellar environments, revealing significant cross section enhancements at low neutrino energies during supernova core collapse.

Contribution

It extends the quasiparticle random phase approximation to finite temperatures using Thermo-Field-Dynamics, providing new insights into thermal effects on neutrino-nucleus interactions.

Findings

Thermal population increases cross sections at low neutrino energies.

Enhancement mainly due to neutrino up-scattering at finite temperatures.

Results agree with large-scale shell-model studies.

Abstract

Thermal effects for inelastic neutrino-nucleus scattering off even-even nuclei in the iron region are studied. Allowed and first-forbidden contributions to the cross sections are calculated within the quasiparticle random phase approximation, extended to finite temperatures within the Thermo-Field-Dynamics formalism. The GT$_0$ strength distribution at finite temperatures is calculated for the sample nucleus $^{54}$Fe. The neutral-current neutrino-nucleus inelastic cross section is calculated for relevant temperatures during the supernova core collapse. The thermal population of the excited states significantly enhances the cross section at low neutrino energies. In agreement with studies using a large scale shell-model approach the enhancement is mainly due to neutrino up-scattering at finite temperatures.