Nucleon form factors and couplings with $N_\mathrm{f} = 2 + 1$ Wilson fermions

TL;DR

This paper reports on calculations of nucleon form factors and axial coupling using advanced lattice QCD techniques with Wilson fermions, highlighting challenges from excited state contamination and the use of variance reduction methods.

Contribution

It provides updated lattice QCD results for nucleon properties with near-physical pion masses using large, fine lattices and the truncated-solver method.

Findings

Results on nucleon electromagnetic form factors

Measurements of axial coupling at near-physical pion masses

Identification of excited state contamination challenges

Abstract

We present updated results on the nucleon electromagnetic form factors and axial coupling calculated using CLS ensembles with $N_\mathrm{f}=2+1$ dynamical flavours of Wilson fermions. The measurements are performed on large, fine lattices with a pseudoscalar mass reaching down to 200 MeV. The truncated-solver method is employed to reduce the variance of the measurements. Estimation of the matrix elements is challenging due to large contamination from excited states and further investigation is necessary to bring these effects under control.