Exploring Key Reactions for Heavy Element Production in the Weak r-process*

The remarkable multi-messenger observation of the merger of two binary neutron stars has significantly advanced our understanding of heavy element synthesis through the rapid neutron capture process (r-process). However, investigations into ultra-metal-poor stars provide compelling evidence that suggests the existence of an additional r-process site responsible for generating the lightest heavy elements. Among the potential candidates for the production of weak r-process elements, neutrino-driven winds following core-collapse supernova explosions have emerged as a promising avenue. However, recent sensitivity studies have revealed that uncertainties in (α,n) reaction rates hinder the accurate prediction of elemental abundances in this specific astrophysical scenario. Unfortunately, our current knowledge of these essential reaction rates remains limited, primarily due to the challenges associated with low-intensity radioactive beams and the inherently small cross sections.

 

Fortunately, recent progress in experimental techniques and the expanding capabilities of radioactive ion beam facilities have enabled us to experimentally explore these important reactions. In this talk, I will present the latest experimental endeavors focused on constraining these reactions, utilizing the Multi Sampling Ionization Chamber (MUSIC) detector.