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

Abstract

A recent, careful analysis of the world data on pp scattering concluded that the pp${\pi }^0$ coupling constant was 3%–4% less than expected from charge independence and the known pn${\pi }^{+}$ coupling constant. We propose a much simpler interpretation of the analysis of the 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.