r-process nucleosynthesis studies meet the next generation of observation and experiment

Nicole Vassh, University of Notre Dame
Monday, Dec 02, 11:00 AM - FRIB Theory Fellow Candidate Seminar
1200 FRIB Laboratory

Abstract:  The astrophysical site(s) for the rapid neutron capture process which synthesizes the heaviest elements observed in nature has been a long outstanding question. The era of multi-messanger astronomy now permits unprecedented insights into astrophysical events, as evidenced by LIGO/VIRGO's ability to direct the telescope community to perform detailed electromagnetic follow-up for merger events such as GW170817. Nuclear physics experiment is simultaneously undergoing its own era of revolution by beginning to probe the very neutron-rich regions populated at crucial times during the r process, as is being done by the CPT at CARIBU. The next generation of nuclear physics experiment will push the boundary of explored nuclei even further. FRIB will produce hundreds of neutron-rich species for the first time, making them accessible for numerous studies which determine properties such as masses or beta-decay half-lives. But what exactly do these revolutions in experiment and observation mean for our understanding of the origin of the heaviest elements in our galaxy? The r-process nucleosynthesis studies I will present explicitly connect these avenues of exploration via considering how nuclear data influences r-process observational signatures. We will discuss the current uncertainties affecting r-process calculations and how these will be reduced by next generation experiments. Since the electromagnetic signal from merger events is highly influenced by the presence of high opacity lanthanide elements, we will focus our discussion on a feature of enhanced lanthanide production, the r-process rare-earth abundance peak, which could be intimately linked to the nuclear structure and deformation of neutron-rich lanthanide species. The alternative means by which the rare-earth peak can be produced is via late-time fission deposition which we will also examine in the context of new theoretical fission yields for neutron-rich nuclei. The question of where nature primarily produces the heavy elements can only be answered through such collaborative efforts between theory, experiment, and observation.