Radiative neutron capture reactions and their sensitivity to the astrophysical s-process

Radiative neutron capture reactions play important roles in heavy element nucleosynthesis processes, e.g., s-, r- and p-processes. Relativistic-mean-field calculations have been performed to obtain nuclear radial density profile in nuclei that lie in and around various proton and neutron shell closures in the nucleosynthesis path of s-process. Microscopic nucleon-nucleon interactions, namely, the density dependent M3Y interaction have been folded with these radial matter densities of target nuclei to obtain the complex microscopic neutron optical model potential (OMP). This potential has been utilized to study the low energy neutron capture reactions in the compound nuclear Hauser-Feshbach formalism for nuclei that take part in various heavy element nucleosynthesis processes. A simplified network for the s-process, taking into consideration suitable astrophysical conditions, has been constructed and subsequently solved numerically to yield the desired abundances. In this large and coupled network involving more than 350 nuclei, we have utilized our calculated neutron capture rates as inputs. A study of neutron capture rate sensitivity has been performed and rates having high impact on the main component of the s-process nucleosynthesis are identified. Using this sensitivity study, the impact of these statistical model rates on the s-process has also been studied. (author)