Neutron skins and neutron stars

TL;DR

This paper uses covariance analysis on a relativistic model to quantify the correlation between neutron skin thickness in lead-208 and neutron star properties, highlighting the potential of precise measurements to constrain neutron-star matter equations of state.

Contribution

It provides the first theoretical error estimates and correlation analysis linking neutron skin measurements to neutron star characteristics.

Findings

Strong correlation between neutron skin and neutron star observables

Theoretical errors are quantified using covariance analysis

Precise measurements could significantly constrain neutron-star matter models

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 {\sl "FSUGold"} is used to quantify theoretical errors and correlation coefficients. Results: We find correlation coefficients of nearly one (or minus one) 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 PREX measurement, ideally with a 0.5% accuracy, could significantly constrain the equation of state of neutron-star matter.