Spin-Orbit Coupling in the Proton-Proton Interaction

The proton-proton interaction is examined at high energies. A phenomenological potential is derived from the scattering data. In the triplet state, this potential has a strong short-range ({~}0.4×{}10^-13 cm) repulsive core region, outside of which a long-ranged tensor force and extremely short-range spin-orbit (L·{}S) force are effective. Good fits can be obtained to all the p-p data below 310 Mev. More important, at 310 Mev the calculated phase shifts are very close to the phase shifts which give the best fit found in a phase-shift analysis of the 310-Mev data, and at all lower energies precision fits to the experimental data can be obtained by very slight (if any) changes in the calculated phase shifts.