INSTANTONS AND THE NON-PERTURBATIVE QUARK DYNAMICS IN THE CHIRAL REGIME

We use th Interacting Instanton Liquid Model to investigate the non-perturbative interaction associated to spontaneous chiral symmetry breaking. In particular, we study how hadrons' structure changes as a function of the quark mass. To support the validity of this model in the chiral regime, the quark mass dependencies of several properties are shown to agree with chiral perturbation theory, including the density of eigenmodes of the Dirac operator and the masses of the pion and nucleon. We identify a natural mass scale m* = 80 MeV which sets the boundary of the mass regime where the non-perturbative QCD dynamics is determined by chiral effects.