Nucleon-NucleonT-Violating Force from Electromagnetic Interaction

A $T$-violating nucleon-nucleon potential is calculated with a model in which the basic violation is in the electromagnetic interaction. The conditions of Hermiticity and current conservation are applied to choose a $T$-violating matrix element of the nucleon electromagnetic current. Since current conservation requires that the $T$-violating term vanish on the mass shell, the longest-range force comes from diagrams corresponding to the exchange of one photon and one pion. In leading nonrelativistic order, there are three spindependent $T$-violating forces of range roughly equal to the Compton wavelength of the pion and of "strength" about 0.01% of the one-pion-exchange potential.