Shell-model half-lives including first-forbidden contributions for r-process waiting-point nuclei

We have performed large-scale shell-model calculations of the half-lives and neutron-branching probabilities of the r-process waiting-point nuclei at the magic neutron numbers N = 50, 82, and 126. The calculations include contributions from allowed Gamow-Teller and first-forbidden transitions. We find good agreement with the measured half-lives for the N = 50 nuclei with charge numbers Z = 28-32 and for the N = 82 nuclei Ag-129 and Cd-130. The contribution of forbidden transitions reduce the half-lives of the N = 126 waiting-point nuclei significantly, while they have only a small effect on the half-lives of the N = 50 and 82 r-process nuclei. DOI: 10.1103/PhysRevC.87.025803