Comparing experimental and calculated electron-capture rates of pf-shell nuclei in explosive stellar environments

Abstract

In explosive stellar environments electron-capture rates on pf-shell nuclei are needed to model core-collapse and thermonuclear supernovae. Electron-capture (EC) rates can be determined from Gamow-Teller (GT) transitions in the β + direction with strength B(GT+). These distributions can be extracted from charge-exchange measurements and from distributions calculated with theoretical models. In a recent study of 13 pf-shell nuclei with measured B(GT+) distributions, we presented a systematic comparison between the electron-capture rates determined from measurements and those determined from shell model (with KB3G and GXPF1a interaction Hamiltonians) and quasiparticle random phase approximation (QRPA) calculations of B(GT+) distributions. The electron-capture rates derived from calculations were compared to rates derived from measurements at two stellar density (temperature) conditions, ρYe=107 g/cm3 (3×109 K) and ρYe=109 g/cm3 (10×109 K). In this work we summarize the results of the study.