Cutoff effects in twisted mass lattice QCD

TL;DR

This paper investigates cutoff effects in twisted mass lattice QCD with O(a) improvement, showing residual discretization errors are small at typical lattice spacings, thus validating the approach for precise QCD computations.

Contribution

First numerical study of cutoff effects in O(a) improved twisted mass lattice QCD using Schroedinger functional correlation functions.

Findings

Residual cutoff effects are at the few percent level at 0.1 fm lattice spacing.

Precise results for meson masses and decay constants are obtained in the quenched approximation.

The approach allows detailed study of continuum limit with moderate computational effort.

Abstract

We present a first numerical study of lattice QCD with O(a) improved Wilson quarks and a chirally twisted mass term. Renormalized correlation functions are derived from the Schroedinger functional and evaluated in an intermediate space-time volume of size 0.75^3 x 1.5 fm^4. In the quenched approximation precise results are then obtained with a moderate computational effort, allowing for a detailed study of the continuum approach. The latter is discussed in terms of observables which converge to meson masses and decay constants in the limit of large space-time volume. In the O(a) improved theory we find residual cutoff effects to be at the level of a few percent for lattice spacings of about 0.1 fm.