Neutron skins and neutron stars

Abstract

Background: The neutron skin of a heavy nucleus as well as many neutron-star properties are highly sensitive to the poorly constrained density dependence of the symmetry energy.Purpose: To provide for the first time meaningful theoretical errors and to assess the degree of correlation between the neutron-skin thickness of ${}^{208}$Pb and several neutron-star properties.Methods: A proper covariance analysis based on the predictions of an accurately calibrated relativistic functional ``FSUGold'' is used to quantify theoretical errors and correlation coefficients.Results: We find correlation coefficients of nearly 1 (or $\ensuremath{-}1$) between the neutron-skin thickness of ${}^{208}$Pb and a host of observables of relevance to the structure, dynamics, and composition of neutron stars.Conclusions: We suggest that a follow-up Lead Radius Experiment (PREX) measurement, ideally with a $0.5%$ accuracy, could significantly constrain the equation of state of neutron-star matter.