QCD correlation functions and instantons

Abstract

QCD point-to-point correlation functions at distances .2-1 fm are very different for different channels, and they tell us a lot about inter-quark interactions. Recent studies based on experimental data, ‘instanton liquid’ approach and lattice measurements are reviewed. Agreement between all of them show that instanton-induced forces dominate the light quark physics, and new findings by Negele et al, that hadrons survive ‘cooling’, make this statement obvious. We also argue that chiral symmetry restoration is due to breaking of the ‘instanton liquid’ into polarized ‘instanton molecules’.