Gamow-Teller strength distributions and electron capture rates for 55Co and 56Ni

TL;DR

This paper calculates Gamow-Teller strength distributions and electron capture rates for 55Co and 56Ni using the proton-neutron quasiparticle random phase approximation, highlighting differences with shell model results across a wide temperature and density range.

Contribution

It introduces a comprehensive calculation of weak interaction rates for key nuclei in supernovae using the QRPA method, providing new insights into their behavior at various astrophysical conditions.

Findings

Electron capture rates are enhanced at presupernova temperatures.

GT strength is fragmented over many final states.

Differences observed compared to shell model calculations.

Abstract

The Gamow-Teller strength (GT) distributions and electron capture rates on 55Co and 56Ni have been calculated using the proton-neutron quasiparticle random phase approximation theory. We calculate these weak interaction mediated rates over a wide temperature (0.01x109 - 30x109 K) and density (10 - 1011 g cm-3) domain. Electron capture process is one of the essential ingredients involved in the complex dynamics of supernova explosion. Our calculations of electron capture rates show differences with the reported shell model diagonalization approach calculations and are comparatively enhanced at presupernova temperatures. We note that the GT strength is fragmented over many final states.