Evidence for the role of instantons in hadron structure from lattice QCD

Abstract Cooling is used as a filter on a set of gluon fields sampling the Wilson action to selectively remove essentially all fluctuations of the gluon field except for the instantons. The close agreement between quenched lattice QCD results with cooled and uncooled configurations for vacuum correlation functions of hadronic currents and for density-density correlation functions in hadronic sound states provides strong evidence for the dominant role of instantons in determining light hadron structure and quark propagation in the QCD vacuum.