Spin-orbit terms of the heavy-quark potential in the presence of instantons

Abstract

Spin-orbit ($\overrightarrow{\sigma }·\overrightarrow{\mathrm{L}}$) terms of the heavy-quark potential are calculated taking into account the effect of instantons in the dilute-gas approximation. It is shown that these terms can be expressed by means of differential operators acting on a certain potential $\tilde{V}$ which is not related to the spin-independent potential of Callan et al. A rough estimate of the terms is also presented.