Charged current neutrino processes in hot nuclear matter with a recent Skyrme parametrization constrained by microscopic calculations

TL;DR

This study evaluates neutrino processes in hot nuclear matter relevant to supernovae and neutron stars using a recent Skyrme interaction, revealing significant differences from previous models and suggesting improvements for astrophysical simulations.

Contribution

It introduces the use of the recent Sky3s Skyrme parametrization for calculating neutrino rates, showing notable differences from the SLy4 interaction and assessing their impact on astrophysical models.

Findings

Neutrino rates with Sky3s differ by up to an order of magnitude from SLy4.

The standard β equilibrium condition is less violated at finite temperature with Sky3s.

Differences between full RPA and Landau approximation are minor for astrophysical relevance.

Abstract

Neutrino processes are important in the modeling of supernova explosions, proto-neutron star evolution, and binary neutron star mergers. We study neutrino production and absorption in proto-neutron star and supernova matter and direct Urca neutrino emission of neutron star matter in the framework of the random phase approximation (RPA). As interactions, we employ the recent extended Skyrme parametrization Sky3s whose effective masses and spin-dependent terms were adjusted to microscopic calculations, and the SLy4 parametrization that was used in previous calculations of neutrino rates. The rates obtained for Sky3s differ from those for SLy4 by up to one order of magnitude for some processes and energy regions. We also determine the electron, muon, and proton fractions that lead to a stationary composition of matter for a density above the direct Urca threshold, and find that with Sky3s the standard $\beta$ equilibrium condition is not as badly violated at finite temperature as predicted in the literature. There are also minor differences between the full RPA and the common Landau approximation, but they are probably not significant for astrophysical simulations. We conclude that it would be worthwhile to repeat the calculation of neutrino rates for the use in astrophysical simulations, and the corresponding simulations, with several and better constrained interactions than SLy4, such as Sky3s.