Electroweak Measurements of Neutron Densities at JLab, USA

Conference · Sat Sep 01 04:00:00 EDT 2018

DOI:https://doi.org/10.2172/1984019· OSTI ID:1984019

Michaels, Robert ^[1]

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1. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

Measurement of the parity-violating electron scattering asymmetry from 208Pb has demonstrated a new opportunity at Jefferson Lab to measure the weak charge distribution and hence pin down the neutron radius and the density-dependence of the symmetry energy 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 208Pb and 48Ca respectively. PREX-I ran in 2010, and CREX and a second run of PREX are currently in preparation to run in 2019. These are both doubly-magic nuclei whose first excited state can be discriminated by the high resolution spectrometers at JLab. The heavier lead nucleus, with a neutron excess, provides an interpretation of the neutron skin thickness in terms of properties of bulk neutron matter. For the lighter 48Ca nucleus, which is also rich in neutrons, microscopic nuclear theory calculations are feasible and are sensitive to poorly constrained 3-neutron forces.

• Research Organization: Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP)
• DOE Contract Number: AC05-06OR23177
• OSTI ID: 1984019
• Report Number(s): JLAB-PHY-18-2921; DOE/OR/23177-6324
• Country of Publication: United States
• Language: English