Implications of PREX-2 on the electric dipole polarizability of neutron rich nuclei

Understand

The recent announcement by the PREX collaboration of an unanticipated thick neutron skin in 208Pb (Rskin208) has challenged our understanding of neutron rich matter in the vicinity of nuclear saturation density.

• Whereas earlier constraints indicate that the symmetry energy is relatively soft, the PREX-2 result seems to suggest the opposite.
• We confront constraints on the symmetry energy obtained from measurements of the electric dipole polarizability against those informed by the PREX-2 measurement of Rskin208 and by the correlations that it entails.
• Covariant energy density functionals informed by the properties of finite nuclei are used to compute the electric dipole response of 48Ca, 68Ni, 132Sn, and 208Pb.