The aim is to give you an overview over central features of the nucleon-nucleon interaction and how it is constructed, with both technical and theoretical approaches.

• The existence of the deuteron with \( J^{\pi}=1^+ \) indicates that the force between protons and neutrons is attractive at least for the \( ^3S_1 \) partial wave. Interference between Coulomb and nuclear scattering for the proton-proton partial wave \( ^1S_0 \) shows that the NN force is attractive at least for the \( ^1S_0 \) partial wave.
• It has a short range and strong intermediate attraction.
• Spin dependent, scattering lengths for triplet and singlet states are different,
• Spin-orbit force. Observation of large polarizations of scattered nucleons perpendicular to the plane of scattering.