Neutron rich nuclei and neutron stars

TL;DR

This paper discusses measurements of neutron-rich nuclei and neutron star properties, highlighting recent experimental results, observational constraints, and a new energy functional that links nuclear data with neutron star structure.

Contribution

It introduces a new energy functional fitted to nuclear and neutron star data, reducing reliance on microscopic calculations and improving predictions of neutron-rich nuclei.

Findings

PREX experiment measures neutron radius of 208Pb.

Neutron star observations constrain the equation of state.

New energy functional predicts drip lines and properties of neutron-rich nuclei.

Abstract

The PREX experiment at Jefferson Laboratory measures the neutron radius of 208Pb with parity violating electron scattering in a way that is free from most strong interaction uncertainties. The 208Pb radius has important implications for neutron rich matter and the structure of neutron stars. We present first PREX results, describe future plans, and discuss a follow on measurement of the neutron radius of 48Ca. We review radio and X-ray observations of neutron star masses and radii. These constrain the equation of state (pressure versus density) of neutron rich matter. We present a new energy functional that is simultaneously fit to both nuclear and neutron star properties. In this approach, neutron star masses and radii constrain the energy of neutron matter. This avoids having to rely on model dependent microscopic calculations of neutron matter. The functional is then used to predict the location of the drip lines and the properties of very neutron rich heavy nuclei.