Lattice cutoff effects for F_Ds with improved Wilson fermions - a final lesson from the quenched case

TL;DR

This paper investigates lattice cutoff effects on the decay constant f_Ds using improved Wilson fermions in the quenched approximation, highlighting the importance of fine lattice spacing for accurate continuum limit extrapolation.

Contribution

It provides a detailed analysis of lattice cutoff effects and scaling behavior for f_Ds and related quantities in quenched lattice QCD with improved Wilson fermions.

Findings

Linear scaling observed for a<~0.08fm

Significant cutoff contaminations on coarser lattices

Insights into charm quark mass and decay constant ratios

Abstract

In view of the recent excitement about a tension between determinations of f_Ds from experiment and from simulations of lattice QCD with dynamical quarks, we try to clear up the picture of lattice determinations in the continuum limit of the quenched approximation. For O(a) improved Wilson quarks we see linear scaling in the squared lattice spacing a^2 only for a<~0.08fm. For coarser lattices we observe significant contaminations from higher order cutoff effects. As an aside we also study the scaling of the charm quark mass and the ratio of the vector to the pseudo-scalar decay constant and the spin-splitting.