Statistical Hauser-Feshbach model description of $(n,α)$ reaction cross sections for the weak s-process

Abstract

The (n, α) reaction contributes in many processes of energy generation and nucleosynthesis in stellar environment. Since experimental data are available for a limited number of nuclei and in restricted energy ranges, at present only theoretical studies can provide predictions for all astrophysically relevant (n, α) reaction cross sections. The purpose of this work is to study (n, α) reaction cross sections for a set of nuclei contributing in the s-process nucleosynthesis. Theory framework is based on the statistical Hauser-Feshbach model implemented in TALYS code and supplemented with nuclear properties based on Skyrme energy density functional. In addition to the analysis of the properties of calculated (n, α) cross sections, the Mawellian averaged cross sections are described and analyzed for the range of temperatures in stellar environment. Model calculations determined astrophysically relevant energy windows in which (n, α) reactions occur in massive stars. In order to reduce the uncertainties in modeling (n, α) reaction cross sections for the s-process, novel experimental studies are called for. The results on the predicted relevant (n, α) reaction energy windows for the s-process nuclei provide a guidance for the priority energy ranges for the future experimental studies.