Instanton effects on the heavy-quark static potential
  We investigate the instanton effects on the heavy-quark potential,including its spin-dependent part, based on the instanton liquid model. Starting with the central potential derived from the instanton vacuum, we obtain the spin-dependent part of the heavy-quark potential. We discuss the results of the heavy-quark potential from the instanton vacuum. We finally solve the nonrelativistic two-body problem, associating with the heavy-quark potential from the instanton vacuum. The instanton effects on the quarkonia spectra are marginal but are required for quantitative description of the spectra. 
U. Yakhshiev, Hyun-Chul Kim, B. Turimov, M.M. Musakhanov, and Emiko   Hiyama
hep-ph hep-ex hep-lat