Mesons and the structure of nucleons. Part IV. The nucleon-nucleon potential

Abstract

The atomic model, in which physical nucleons are described as compound systems of a nucleon core plus a single pion, has been used as the basis for a computation of the low-energy interaction between two physical nucleons. Advantage is taken of previous work for the specification of the interaction between the pion and the nucleon core in the different possible states of total angular momentum and isotopic spin. An initial simplification, where we replace one of the “atoms” by an “effective scattering center” is only moderately successful in reproducing the gross features of the observed nucleon-nucleon interaction. The full computation (approached in the spirit of the Heitler-London approximation to the H-H interaction) improves on the qualitative fit, but it turns out to be impossible to reproduce simultaneously the asymptotic behavior of both the central and tensor terms in the nucleon-nucleon potential using a reasonable set of pion-core interactions. A significant result is the derivation, using the simplified model, of a nucleon-nucleon spin-orbit interaction whose range is shorter than that of the other terms in the potential. Our computation thus provides a strong indication that the spin-orbit interaction may arise from the same features of the pion-nucleon interaction as give rise to the resonant pion-nucleon scattering in the state of T = J = 3 2 .