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.
