Effects of Instantons on the Excited Baryons and Two-Nucleon Systems

Abstract

The effects of the spin-orbit and the tensor parts of the instanton-induced interaction on the excited nonstrange baryons up to $N$=2 and on the two-nucleon systems are investigated. The spin-orbit force from the instanton-induced interaction cancels most of that from the one-gluon exchange in the excited baryons while the spin-orbit force in the nucleon systems remains strong after the inclusion of the instanton-induced interaction. The model including the spin-orbit and the tensor terms of the instanton-induced interaction as well as the one-gluon exchange is found to reproduce successfully the excited baryon mass spectrum and the scattering phase shifts of two nucleons in the spin-triplet relative $P$-wave state.