Impact of intrinsic electromagnetic structure on the nuclear charge radius in relativistic density functional theory

In this study, the effects of the nucleon's intrinsic electromagnetic (EM) structure on the nuclear charge radius have been explored within the framework of the relativistic Hartree-Bogoliubov theory. It is found that the intrinsic EM structure corrections could make an effect for accurately describing the evolution of nuclear charge radius. After taking into account the intrinsic EM structure corrections, the descriptions of the evolution of charge radii for Pb, Sn, and Cd isotopes have been improved within relativistic density functional theory. Using the Pb isotopic chain as an example, the improvement in charge radii can be primarily attributed to the intrinsic neutron and neutron spin-orbit terms of the intrinsic EM structure. Additionally, nuclear charge densities and corresponding isotopic evolution in Pb isotopes have been discussed.