Non-perturbative improvement of quark mass renormalization in two-flavour lattice QCD

TL;DR

This paper non-perturbatively determines key renormalization constants and improvement coefficients in two-flavour lattice QCD using the Schrödinger functional scheme, covering both weak-coupling and typical simulation regimes.

Contribution

It provides non-perturbative results for renormalization and improvement coefficients in two-flavour lattice QCD, applicable to heavy and charm quark physics.

Findings

Results cover weak-coupling and typical simulation regions.

Enables non-perturbative renormalization for heavy quarks.

Supports charm physics applications.

Abstract

We non-perturbatively determine the renormalization constant and the improvement coefficients relating the renormalized current and subtracted quark mass in O(a) improved two-flavour lattice QCD. We employ the Schr\"odinger functional scheme and fix the physical extent of the box by working at a constant value of the renormalized coupling. Our calculation yields results which cover two regions of bare parameter space. One is the weak-coupling region suitable for volumes of about half a fermi. By making simulations in this region, quarks as heavy as the bottom can be propagated with the full relativistic QCD action and renormalization problems in HQET can be solved non-perturbatively by a matching to QCD in finite volume. The other region refers to the common parameter range in large-volume simulations of two-flavour lattice QCD, where our results have particular relevance for charm physics applications.