STRUCTURE OF THE QCD VACUUM AND HADRONS

Recent studies have provided strong arguments in favor of the idea tha t most hadrons (including the nucleon) are actually bound not because of confining forces, but mainly due to the instanton-induced forces. Q uite different effective interactions in various mesonic and baryonic channels can be explained in this way. Moreover, many hadronic paramet ers and even the point-to-point correlation functions are quantitative ly reproduced by the simplest possible ensemble of instantons, the so- called ''Random Instanton Liquid Model'' (RILM). Recent lattice works have confirmed it, essentially deriving the ''instanton vacuum'' from lattice configuration by their ''cooling''. At non-zero temperatures t he (quark-induced) interaction between instantons becomes much stronge r, and at the critical temperature T = T-c the chiral symmetry becomes restored, due to ''pairing'' of the instantons and the anti-instanton s into a kind of ''(I) over bar I molecules''.