Sensitivity studies for the weak r-process: neutron capture*

The heaviest elements in our universe are manufactured via the rapid neutron capture process (r-process). The solar r-process pattern exhibits three distinct peaks at A ~ 80, 130, and 195 where the positions of the higher-mass, main r-process (A ~130, 195) peaks and the lighter-mass, weak r-process peak (A~80) roughly correspond to more and less neutron-rich conditions, respectively. Comparing the solar r-process pattern to the elemental abundance patterns of metal-poor stars in our Galaxy shows there is better agreement in the main r-process regime compared to the lighter elements making the weak r-process region (70 < A < 120) pivotal to explore r-process origins. While many of the relevant pieces of nuclear data such as masses and half-lives are measured for weak r-process species, little is known about their neutron capture rates. Here we describe a set of neutron capture sensitivity studies for weak r-process species, including both individual and global Monte Carlo variations. We aim to better understand the nuclear physics uncertainties of r-process simulations that are compared with observational data and to inform experimentalists of potentially impactful measurements.