s-process stellar enhancement factors obtained within the statistical model with parity-dependent level densities

Abstract.

In stellar environments the medium modifications of the neutron capture cross-sections required for s-process nucleosynthesis simulations are accounted for by the stellar enhancement factors. We have calculated these enhancement factors using the statistical model for compound reactions. Improving previous calculations we take the parity distribution of states at all stages of the reaction into account by using parity-dependent level densities. The effect of this improvement on the stellar enhancement factors is small, although not negligible if one attempts to describe the stellar capture rates with an accuracy of order 10%. We observe, however, that the uncertainties introduced by the insufficient knowledge of the total level densities are noticeably larger.