Confinement, chiral symmetry breaking and Faddeev-Niemi decomposition in QCD

We identify two distinct, complementary classes of gauge field configuratio ns for QCD with SU(2) gauge group, one (instanton-like configurations) havi ng to do with chiral symmetry breaking but not with confinement, the other (regularized Wu-Yang monopoles) very likely responsible for confinement but unrelated to chiral symmetry breaking. Our argument is based on a semiclas sical analysis of fermion zero modes in these backgrounds, made by use of a gauge field decomposition recently introduced by Faddeev and Niemi. Our re sult suggests that the two principal dynamical phenomena in QCD, confinemen t and chiral symmetry breaking, are distinct effects, caused by two competi ng classes of gauge field configurations. (C) 2001 Elsevier Science B.V. Al l rights reserved.