Electroweak Measurements of Neutron Densities in PREX and CREX at JLab, USA

TL;DR

This paper discusses measurements of neutron densities in lead and calcium nuclei using parity-violating electron scattering at Jefferson Lab, providing insights into neutron distributions with minimal model dependence.

Contribution

It introduces the PREX and CREX experiments that measure neutron radii in nuclei through weak charge distribution, a novel approach in nuclear physics.

Findings

Successful measurement of neutron skin in ${}^{208}$Pb

Development of experimental techniques for weak charge distribution

Preparation for further runs to improve data accuracy

Abstract

Measurement of the parity-violating electron scattering asymmetry from ${}^{208}$Pb has demonstrated a new opportunity at Jefferson Lab to measure the weak charge distribution and hence pin down the neutron radius in nuclei in a relatively clean and model-independent way. This is because the Z boson of the weak interaction couples primarily to neutrons. We will describe the PREX and CREX experiments on ${}^{208}$Pb and ${}^{48}$Ca respectively. PREX-I ran in 2010, and CREX and a second run of PREX are currently in preparation.