Neutron rich matter in the laboratory and in the heavens after GW170817

TL;DR

The paper discusses how GW170817 has enhanced our understanding of neutron-rich matter, r-process nucleosynthesis, and neutron star properties, highlighting recent experimental and observational advances and future prospects.

Contribution

It reviews recent observational, experimental, and theoretical progress in understanding neutron-rich matter and r-process nucleosynthesis following GW170817.

Findings

Neutron star mergers are confirmed as key sites for heavy element production.

GW170817 provided constraints on neutron star equation of state and deformability.

Upcoming experiments like FRIB and PREX II will refine nuclear physics inputs.

Abstract

The historic observations of the neutron star merger GW170817 advanced our understanding of r-process nucleosynthesis and the equation of state (EOS) of neutron rich matter. Simple neutrino physics suggests that supernovae are not the site of the main r-process. Instead, the very red color of the kilonova associated with GW170817 shows that neutron star (NS) mergers are an important r-process site. We now need to measure the masses and beta decay half-lives of very neutron rich heavy nuclei so that we can more accurately predict the abundances of heavy elements that are produced. This can be done with new radioactive beam accelerators such as the Facility for Rare Isotope Beams (FRIB). GW170817 provided information on the deformability of NS and the equation of state of dense matter. The PREX II experiment will measure the neutron skin of ${}^{208}$Pb and help constrain the low density EOS. As the sensitivity of gravitational wave detectors improve, we expect to observe many more events. We look forward to exciting advances and surprises!