QRPA calculations of stellar weak-interaction rates

Abstract

Weak-decay rates under various stellar density and temperature conditions are studied in several mass regions including neutron-deficient mediummass waiting-point nuclei involved in the rp-process, neutron-rich mediummass isotopes involved in the r-process, and pf-shell nuclei of special importance as constituents in presupernova formations. Weak rates are relevant to understand the late stages of the stellar evolution, as well as the nucleosynthesis of heavy nuclei. The nuclear structure involved in the weakdecay processes is described within a microscopic deformed quasiparticle random-phase approximation (QRPA) based on a selfconsistent mean field obtained from Skyrme Hartree–Fock + BCS calculations. This approach reproduces reasonably well both the experimental β-decay half-lives and the Gamow–Teller strength distributions measured under terrestrial conditions.