On the Present Status of the Problem of Charge Dependence and Charge Asymmetry of the Nucleon‐Nucleon Force

Abstract

AbstractThe charge dependence of the nucleon‐nucleon force can be derived from the low‐energy scattering parameters. The p‐p and n‐p parameters were measured in direct scattering experiments. The n‐n parameters ann = (‐16.70 ± 0.38) fm and rnn = (2.78 ± 0.13) fm have been determined from few particle reactions. The difference of the scattering lengths (ann ‐ ann) ≈ 7 fm demonstrates the violation of the charge independence. Information on the charge symmetry is still doubtful due to the inaccuracy of the charge correction for the p‐p parameters. Whereas the n‐n and the charge corrected p‐p parameters known at present yield a weaker n‐n force than the p‐p force, the opposite result follows from the binding energy difference for 3He and 3H and the meson theory of the nuclear forces.