Investigation of ( <i>n</i> , <i>γ</i> ) rates of ^79,81 Br and ^85,87 Rb in the <i>s</i> -process nucleosynthesis

Abstract We report a systematic investigation of neutron capture reactions on 79,81 Br and 85,87 Rb under conditions characteristic of the weak s -process in massive stars. Employing the Hauser–Feshbach frameworks in TALYS v1.97 and YAHFC v3.66, we explore a broad suite of nuclear level density and γ strength models, both phenomenological and microscopic, to assess their influence on Maxwellian-averaged cross sections. By benchmarking our predictions against available experimental data, we identify model combinations that consistently reproduce observed trends, thereby greatly reducing uncertainties in the cross sections. The results provide experimentally validated reaction rates that can strengthen the reliability of s -process nucleosynthesis simulations.