Operator product expansion and quark condensate from LQCD in coordinate space

Abstract

We perform an exploratory study of the operator product expansion of the quark propagator on the lattice at short distance in coordinate space. This permits a simple determination of the quark condensate, <qq>^MS(2 GeV)=(-265\pm 5\pm 22 MeV)^3, and of the renormalization constant of the quark field, Z^MS(2 GeV)=0.871 \pm 0.003 \pm 0.020. This new method also provides a remarkable non-perturbative test of the OPE predictions at short distance in QCD.

6 pp. Talk given at the 23rd International Symposium on Lattice Field Theory: Lattice 2005, Trinity College, Dublin, Ireland, 25-30 July 2005