Neutrino pair emission from thermally excited nuclei in stellar collapse

TL;DR

This paper calculates neutrino-antineutrino pair emission rates from hot nuclei during stellar core collapse, using a finite-temperature quasiparticle random phase approximation to model Gamow-Teller transitions.

Contribution

It introduces a method to compute neutrino emission rates from thermally excited nuclei in supernova conditions using an extended RPA approach.

Findings

Decay rates for ${}^{56}$Fe and ${}^{82}$Ge are quantified at relevant temperatures.

The model provides a framework for understanding neutrino emissions in supernovae.

Results help improve supernova collapse simulations.

Abstract

We examine the rate of neutrino-antineutrino pair emission by hot nuclei in collapsing stellar cores. The rates are calculated assuming that only allowed charge-neutral Gamow-Teller (GT$_0$) transitions contribute to the decay of thermally excited nuclear states. To obtain the GT$_0$ transition matrix elements, we employ the quasiparticle random phase approximation extended to finite temperatures within the thermo field dynamics formalism. The decay rates and the energy emission rates are calculated for the sample nuclei ${}^{56}$Fe and $^{82}$Ge at temperatures relevant to core collapse supernovae.