Neutron-Matter Radii from an Analysis of Pionic Atoms

Abstract
We use the low-energy pion-nucleus interaction as a means for investigating the distribution of nucleons in nuclei. An optical-model analysis of existing experimental data on pionic atoms is used to study possible differences in the rms radii of the neutron and proton densities. The difference in these radii, assumed to be independent of mass number, was found to be -0.01 ± 0.16 F. The absence of any significant difference in these radii should be considered an average behavior for a wide range of nuclei.