Beta decay of deformed $r$-process nuclei near $A\sim 80$ and $A\sim 160$, including odd-$A$ and odd-odd nuclei, with the Skyrme finite-amplitude method

T. Shafer, J. Engel, C. Fröhlich, G. C. McLaughlin, M. Mumpower, R. Surman

PRC 94 055802 (2016)

After identifying the nuclei in the regions near $A=80$ and $A=160$ for which $\beta$-decay rates have the greatest effect on weak and main $r$-process abundance patterns, we apply the finite-amplitude method (FAM) with Skyrme energy-density functionals (EDFs) to calculate $\beta$-decay half-lives of those nuclei in the quasiparticle random-phase approximation (QRPA). We use the equal filling approximation to extend our implementation of the charge-changing FAM, which incorporates pairing correlations and allows axially symmetric deformation, to odd-A and odd-odd nuclei. Within this framework we find differences of up to a factor of seven between our calculated $\beta$-decay half-lives and those of previous efforts. Repeated calculations with nuclei near $A=160$ and multiple EDFs show a spread of two to four in $\beta$-decay half-lives, with differences in calculated Q values playing an important role. We investigate the implications of these results for $r$-process simulations.