Chiral effects in the confining QCD vacuum

Confining configurations are introduced into the standard instanton vacuum model. This drastically improves the theoretical properties of the vacuum: the instanton size density d(ρ) is stabilized at ρ ∼ 0.2 fm, all of the chiral effects are formulated in a gauge-invariant way, and quarks are confined. An interesting interplay of chiral and confining dynamics is observed; for the realistic values of parameters, the Georgi-Manohar picture emerges with the chiral radius Rch ∼ ρ ∼ 0.2 fm much smaller than the confirming radius Rc and hadron radius ∼ 1 fm. In the limit Rch much-lt Rc, the chiral mass Mch(p) is not affected by confinement and can be taken in the local limit Mch(p = 0). Different types of effective chiral Lagrangians (ECL) are obtained, which contain all or a part of gluon, quark and Nambu-Goldstone meson fields. The ECL are manifestly gauge-invariant, and in the limit of no gluon fields, they coincide with those found previously. The problem of the double role of the pion, namely, as a Goldstone meson or as a q bar q system, is briefly discussed using confining ECL with quarks, mesons, and gluons. 34 refs., 4 figs