Superheavy Elements from r-Process Calculations with an Energy-Density Mass Formula

Abstract

Astrophysical superheavy-element synthesis by rapid neutron capture is studied by utilizing nuclear masses from energy-density functional calculations and a new $\beta$-decay formula in a modified r-process code. We find reduced abundances for elements with large atomic numbers relative to those predicted by conventional mass formulas. Calculations have been performed with fission barriers corresponding to both large and small values of the surface-symmetry contribution to the deformation energy. Our results, based on a different mass-formula parametrization, show that it is possible to synthesize superheavy elements in the r process even for very large surface-symmetry contributions if certain mass-formula terms are modified. Also, a more realistic formula for $\beta$-decay rates yields r-process fission-cycle times which are about 1 order of magnitude shorter than previous values.