Recent developments provided evidence that the dimension 2 gluon condensate
is important for the nonperturbative regime of Yang-Mills theories
(quantized in the Landau gauge). We show that it may be relevant for the
Dyson-Schwinger approach to QCD. In order that this approach leads to a
successful hadronic phenomenology, an enhancement of the effective quark-gluon
interaction seems to be needed at intermediate (p^2 \sim 0.5 GeV^2) momenta. It
is shown that the gluon condensate provides such an enhancement. It is
also shown that the resulting effective strong running coupling leads to the
sufficiently strong dynamical chiral symmetry breaking and successful
phenomenology at least in the light sector of pseudoscalar mesons.Comment: revtex4, 4 eps figures, 8 pages, improved presentation, to appear in
Phys. Rev.
