Impact of new data for neutron-rich heavy nuclei on theoretical models for $r$-process nucleosynthesis

TL;DR

This paper reviews how recent measurements of neutron-rich heavy nuclei influence theoretical models of the r-process nucleosynthesis, highlighting the impact of nuclear physics inputs on astrophysical site predictions.

Contribution

It provides a comprehensive analysis of new nuclear data and their effects on r-process models, emphasizing the importance of shell quenching and site conditions.

Findings

New nuclear measurements constrain r-process site models.

Shell quenching affects nucleosynthesis pathways.

Neutron star mergers and supernovae are key sites.

Abstract

Current models for the $r$ process are summarized with an emphasis on the key constraints from both nuclear physics measurements and astronomical observations. In particular, we analyze the importance of nuclear physics input such as beta-decay rates; nuclear masses; neutron-capture cross sections; beta-delayed neutron emission; probability of spontaneous fission, beta- and neutron-induced fission, fission fragment mass distributions; neutrino-induced reaction cross sections, etc. We highlight the effects on models for $r$-process nucleosynthesis of newly measured $\beta$-decay half-lives, masses, and spectroscopy of neutron-rich nuclei near the $r$-process path. We overview r-process nucleosynthesis in the neutrino driven wind above the proto-neutron star in core collapse supernovae along with the possibility of magneto-hydrodynamic jets from rotating supernova explosion models. We also consider the possibility of neutron star mergers as an r-process environment. A key outcome of newly measured nuclear properties far from stability is the degree of shell quenching for neutron rich isotopes near the closed neutron shells. This leads to important constraints on the sites for $r$-process nucleosynthesis in which freezeout occurs on a rapid timescale.