Weak decay rates for waiting-point nuclei involved in the rp-process

Abstract

We study weak interaction rates under the stellar density and temperature conditions encountered in the rp process. Special attention is paid to neutron-deficient waiting-point nuclei. The nuclear structure part of the problem is described within a deformed Skyrme Hartree-Fock + BCS + QRPA approach, which reproduces not only the beta-decay half-lives but also the available Gamow-Teller strength distributions, measured under terrestrial conditions. The various sensitivities of the decay rates to both density and temperature are discussed. In particular, we study the contributions coming from excited states in the parent nucleus, which are thermally populated, and the competition between beta-decays and continuum electron captures.