Mass-improvement of the vector current in three-flavor QCD

TL;DR

This paper accurately determines two improvement coefficients in three-flavor QCD to cancel mass-dependent cutoff effects, using non-perturbative simulations with improved Wilson fermions, marking a systematic first in this area.

Contribution

It provides the first systematic non-perturbative determination of mass-dependent cutoff effects in three-flavor QCD using a robust simulation strategy.

Findings

Accurate estimate of a counterterm for dynamical quark cutoff effects.

First systematic determination of such effects with large significance.

Methodology applicable to other lattice QCD calculations.

Abstract

We determine two improvement coefficients which are relevant to cancel mass-dependent cutoff effects in correlation functions with operator insertions of the non-singlet local QCD vector current. This determination is based on degenerate three-flavor QCD simulations of non-perturbatively O(a) improved Wilson fermions with tree-level improved gauge action. Employing a very robust strategy that has been pioneered in the quenched approximation leads to an accurate estimate of a counterterm cancelling dynamical quark cutoff effects linear in the trace of the quark mass matrix. To our knowledge this is the first time that such an effect has been determined systematically with large significance.