Nucleon average quark momentum fraction with $N_\mathrm{f}=2+1$ Wilson fermions

TL;DR

This paper presents a lattice QCD study of the nucleon’s average quark momentum fraction using $N_f=2+1$ Wilson fermions, employing multiple ensembles and advanced techniques to reduce excited-state contamination, with preliminary results on nucleon charges.

Contribution

It introduces a comprehensive lattice QCD analysis of the nucleon quark momentum fraction with improved excited-state contamination control using the generalized pencil-of-functions method.

Findings

Preliminary results for isovector nucleon charges obtained.

Multiple lattice spacings and pion masses used for robust analysis.

Implementation of generalized pencil-of-functions to reduce excited-state effects.

Abstract

We report on an analysis of the average quark momentum fraction of the nucleon and related quantities using $N_\mathrm{f}=2+1$ Wilson fermions. Computations are performed on four CLS ensembles covering three values of the lattice spacing at pion masses down to $M_\pi \approx 200\,\mathrm{MeV}$. Several source-sink separations ($\sim 1.0\,\mathrm{fm}$ to $\sim 1.4\,\mathrm{fm}$) are used to assess the excited-state contamination. To gain further insight, the generalized pencil-of-functions approach has been implemented to reduce the excited-state contamination in the relevant two- and three-point functions. Preliminary results are shown for the isovector nucleon charges from vector, axial vector and tensor derivative (twist-2) operators.