GT strengths and electron-capture rates for pf-shell nuclei of relevance for late stellar evolution

TL;DR

This study evaluates how well theoretical models reproduce experimental Gamow-Teller strengths in pf-shell nuclei and assesses the impact on stellar electron-capture rates relevant for supernovae.

Contribution

It systematically compares shell-model and QRPA predictions with experimental data for pf-shell nuclei, highlighting their accuracy and implications for astrophysical models.

Findings

Shell-model with KB3G and GXPF1a closely matches experimental GT strengths.

QRPA models show larger deviations from experimental data.

Differences in GT distributions significantly affect stellar electron-capture rate calculations.

Abstract

This paper presents a systematic evaluation of the ability of theoretical models to reproduce experimental Gamow-Teller transition strength distributions measured via (n,p)-type charge-exchange reactions at intermediate beam energies. The focus is on transitions from stable nuclei in the pf shell (45<A<64). The impact of deviations between experimental and theoretical Gamow-Teller strength distributions on derived stellar electron-capture rates at densities and temperatures of relevance for Type Ia and Type II supernovae is investigated. The theoretical models included in the study are based on the shell-model, using the KB3G and GXPF1a interactions, and quasiparticle random-phase approximation (QRPA) using ground-state deformation parameters and masses from the finite-range droplet model.