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Current Experiments Archive

E06-002: PREX - A clean measurement of the neutron skin of 208Pb through parity violating electron scattering

In a heavy nucleus like lead (208Pb), the difference between the neutron radius and the proton radius is believed to be several percent. This neutron skin has not been well established experimentally in stable nuclei. The PREx collaboration plans to measure the neutron charge radius Rn in a clean and model-independent way analogous to the classic measurements of the proton radius Rp and with unprecedented accuracy.

Experimentally, Rn is rather poorly known (to probably only 5 percent). The best estimates of Rn appear to come from nuclear theory, where models have been constrained primarily by data other than measurements of neutron radii. Therefore, a measurement of Rn will provide a powerful independent check of basic nuclear theory. In addition, Rn measures the density dependence of the symmetry energy of neutron rich nuclear matter, which will constrain neutron star theory.

Technical Paper