Abstract :
Bulk nuclear observables such as charge radii and binding energies are well described by both nonrelativistic and covariant mean-field models. However, predictions of neutron radii, which are not tightly constrained by reliable data, vary significantly. The nature of this variation is investigated using correlations between basic properties of the models and the neutron skin thickness in lead. The results suggest that conventional covariant models are too limited. The study is guided by principles and insights of effective field theory (EFT), such as power counting, and the relation of mean-field models to a more general EFT approach to nuclei is discussed.
