Anomaly in the charge radii of Pb isotopes

The anomalous behaviour of the charge radii of the isotopic chain of Pb nuclei has been studied in the relativistic mean-field theory. It has been shown that relativistic mean field provides an excellent description of the anomalous kink in the isotopic shifts about ²⁰⁸Pb. This contrasts strongly from the Skyrme mean field, where the density-dependent Skyrme forces fail to reproduce the observed trend in the emperical data on the charge radii. The results have been discussed in the perspective of differences in the ansätze of the relativistic and the Skyrme mean-field theories.