On the renormalized scalar density in quenched QCD

We present a non-perturbative determination of the renormalization factor ZS of the scalar density in quenched QCD with overlap fermions. Results are obtained at four values of the lattice spacing. By combining ZS with results for the low-energy constant Σ we are able to compute the renormalization group invariant scalar condensate Σ in the continuum limit with a total accuracy of 7%, excluding dynamical quark effects. Our result translates to ΣMS(2 GeV)=(285 ± 9 MeV)3 if the scale is set by the kaon decay constant. We have also performed scaling studies of the pseudoscalar decay constant and the vector mass. Our results indicate that quantities computed using overlap quarks exhibit excellent scaling behaviour, with small residual lattice artifacts. (orig.)