Complete Electric Dipole Response and the Neutron Skin in 208Pb.

A benchmark experiment on 208Pb shows that polarized proton inelastic scattering at very forward angles including 00 is a powerful tool for high-resolution studies of electric dipole (El) and spin magnetic dipole (MI) modes in nuclei over a broad excitation energy range to test up-to-date nuclear models. The extracted El polarizability leads to a neutron skin thickness rSkin = 0. 156+0.025-0.021 fm in 208Pb derived within a mean-field model [Phys. Rev. C 81, 051303 (2010)], thereby constraining the symmetry energy and its density dependence relevant to the description of neutron stars. [ABSTRACT FROM AUTHOR]