Information Content of the Parity-Violating Asymmetry in 208 Pb

Abstract

The parity-violating asymmetry PV in 208Pb, recently measured by the PREX-2 Collaboration, is studied using modern relativistic (covariant) and nonrelativistic energy density functionals. We first assess the theoretical uncertainty on PV which is intrinsic to the adopted approach. To this end, we use quantified functionals that are able to accommodate our previous knowledge on nuclear observables such as binding energies, charge radii, and the dipole polarizability of 208Pb. We then add the quantified value of PV together with to our calibration dataset to optimize new functionals. Based on these results, we predict a neutron skin thickness in 208Pb skin=0.19±0.02 fm and the symmetry-energy slope =54±8 MeV. These values are consistent with other estimates based on astrophysical data and are significantly lower than those recently reported using a particular set of relativistic energy density functionals. We also make a prediction for the PV value in 48Ca that will be soon available from the CREX measurement.