Neutron skin of Pb208, nuclear symmetry energy, and the parity radius experiment

Abstract

A precise determination of the neutron skin Δrnp of a heavy nucleus sets a basic constraint on the nuclear symmetry energy (Δrnp is the difference of the neutron and proton rms radii of the nucleus). The parity radius experiment (PREX) may achieve it by electroweak parity-violating electron scattering (PVES) on Pb208. We investigate PVES in nuclear mean field approach to allow the accurate extraction of Δr np of Pb208 from the parity-violating asymmetry APV probed in the experiment. We demonstrate a high linear correlation between A PV and Δrnp in successful mean field forces as the best means to constrain the neutron skin of Pb208 from PREX, without assumptions on the neutron density shape. Continuation of the experiment with higher precision in APV is motivated since the present method can support it to constrain the density slope of the nuclear symmetry energy to new accuracy. © 2011 American Physical Society.