Meson-Theoretical Origin of the Spin-Orbit Coupling Between Two Nucleons

It is generally agreed that the phenomenological analysis of p-p scattering data at high energies by means of a potential energy function suggests strongly the action of a spin-orbit force in triplet odd states. The situation with respect to the triplet even states is less conclusive, the existing evidence indicating that the spin-orbit coupling is at least weaker and perhaps appeciably weaker here. A conservative meson-theoretical approach is described which yields qualitative results in agreement with the above remarks. Though hardly definitive from a quantitative viewpoint, its essential elements should be contained in a more complete theory. (W.D.M.)