On the renormalized scalar density in quenched QCD

TL;DR

This paper non-perturbatively determines the scalar density renormalization factor in quenched QCD with overlap fermions, enabling precise calculation of the scalar condensate and demonstrating excellent scaling behavior of computed quantities.

Contribution

It provides the first non-perturbative determination of Z_S in quenched QCD with overlap fermions and computes the scalar condensate with high accuracy.

Findings

Renormalization factor Z_S determined with 7% accuracy.

Scalar condensate value obtained as (285±9 MeV)^3.

Overlap quarks show excellent scaling with small lattice artifacts.

Abstract

We present a non-perturbative determination of the renormalization factor Z_S of the scalar density in quenched QCD with overlap fermions. Results are obtained at four values of the lattice spacing. By combining Z_S with results for the low-energy constant Sigma we are able to compute the renormalization group invariant scalar condensate in the continuum limit with a total accuracy of 7%, excluding dynamical quark effects. Our result translates to Sigma_msbar(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.