Explanation of the apparent charge dependence of the pion-nucleon coupling

A recent, careful analysis of the world data on {ital pp} scattering concluded that the {ital pp}{pi}{sup 0} coupling constant was 3%--4% less than expected from charge independence and the known {ital pn}{pi}{sup +} coupling constant. We propose a much simpler interpretation of the analysis of the {ital pp} data which involves no unreasonable level of charge dependence. Instead one must recognize that the pion-nucleon form factor needed in a boson-exchange model of the nucleon-nucleon force differs significantly from that relevant to a free nucleon.