Has a thick neutron skin in ${}^{208}$Pb been ruled out?

TL;DR

This study investigates whether a thick neutron skin in lead-208, suggested by recent experiments, is compatible with existing laboratory and astrophysical data, finding no strong evidence to exclude such models.

Contribution

The paper assesses the compatibility of large neutron-skin thickness in lead-208 with various experimental and astrophysical observations using relativistic models.

Findings

Large neutron skins in ${}^{208}$Pb are not ruled out by current observables.

Models with neutron-skin thickness up to 0.33 fm remain consistent with data.

No decisive evidence excludes the thick neutron skin suggested by PREX.

Abstract

The Lead Radius Experiment (PREX) has provided the first model-independent evidence in favor of a neutron-rich skin in ${}^{208}$Pb. Although the error bars are large, the reported large central value of 0.33\,fm is particularly intriguing. To test whether such a thick neutron-skin in ${}^{208}$Pb is already incompatible with laboratory experiments or astrophysical observations, we employ relativistic models with neutron-skin thickness in ${}^{208}$Pb ranging from 0.16 to 0.33 fm to compute ground state properties of finite nuclei, their collective monopole and dipole response, and mass-{\sl vs}-radius relations for neutron stars. No compelling reason was found to rule out models with large neutron skins in ${}^{208}$Pb from the set of observables considered in this work.