Operator product expansion and quark condensate from lattice QCD in coordinate space

Abstract

We present a lattice QCD determination of the chiral quark condensate based on a new method. We extract the quark condensate from the operator product expansion of the quark propagator at short euclidean distances, where it represents the leading contribution in the chiral limit. From this study we obtain $ {\left\langle {\bar{q}q} \right\rangle }^{{\overline{{{\text{MS}}}} }} {\left( {2\;{\text{GeV}}} \right)} = - {\left( {265 \pm 5 \pm 22\;{\text{MeV}}} \right)}^{3} $ , in good agreement with determinations of this quantity based on different approaches. The simulation is performed by using the ${\cal O}(a)$ -improved Wilson action at $\beta = 6.45$ on a volume 323 × 70 in the quenched approximation.