Fermion guides: a mechanism for spontaneous breakdown of chiral symmetry in QCD

It is suggested that spontaneous breakdown of chiral symmetry in QCD takes place because a special class of gauge-field configurations (''fermion guides'') allow massless quarks to propagate to arbitrarily large distance with an undiminished amplitude. By functional averaging over fermion guide fields an estimate of the pseudoscalar correlation functions reveals the formation of light pseudoscalar q-barq bound states with mass proportional to (m/sub 1/+m/sub 2/)/sup 1/2/..lambda.. for quark masses m/sub 1/,m/sub 2/ much smaller than the QCD mass scale ..lambda... It is shown that unwanted light scalar, vector, or axial-vector states are not produced by this mechanism. The dynamical scheme by which the would-be axial-U(1) Goldstone particle acquires a mass is also discussed.