QUARK PROPAGATOR AND MESON CORRELATORS IN THE QCD VACUUM

Equal time, point to point correlation functions for spatially separat ed meson currents are calculated with respect to a variational constru ct for the ground state of QCD. Given such an ansatz we make no furthe r approximations in the evaluation of the correlators. Our calculation s for the vector, axial vector and scalar channels show qualitative ag reement with the phenomenological predictions, whereas the pseudoscala r channel does not. However, the pseudoscalar correlator, when approxi mated by saturating with intermediate one-pion states agrees with resu lts obtained from spectral density functions parameterised by pion dec ay constant and [-<(psi)over bar psi>)] value obtained from chiral per turbation theory. We discuss this departure in the pseudoscalar channe l, in the context of the quark propagation in the vacuum.