Charge asymmetry of the nucleon-nucleon interaction

Based upon the Bonn meson-exchange model for the nucleon-nucleon (NN) interaction, we study systematically the charge-symmetry-breaking (CSB) of the NN interaction due to nucleon mass splitting. Particular attention is paid to CSB generated by the 2 pi-exchange contribution to the NN interaction, pi p diagrams, and other multimeson exchanges. We calculate the CSB differences in the S-1(0) effective range parameters as well as phase shift differences in S, P, and higher partial waves up to 300 MeV laboratory energy. We find a total CSB difference in the singlet scattering length of 1.6 fm which explains the empirical value accurately. The corresponding CSB phase-shift differences are appreciable at low energy in the S-1(0) state. In the other partial waves, the CSB splitting of the phase shifts is small and increases with energy, with typical values in the order of 0.1 degrees at 300 MeV in P and D waves.