Structure functions and form factors close to the chiral limit from lattice QCD

TL;DR

This paper presents lattice QCD calculations of nucleon structure functions and form factors near the chiral limit, analyzing effects of lattice spacing, quenching, and quark mass to understand systematic uncertainties.

Contribution

It compares results from various fermion formulations and quenching conditions to assess systematic effects in lattice QCD near the chiral regime.

Findings

Small lattice spacing errors observed.

Quenching effects are minimal.

Chiral regime reached only at light quark masses.

Abstract

Results for nucleon matrix elements (arising from moments of structure functions) and form factors from a mixture of runs using Wilson, clover and overlap fermions (both quenched and unquenched) are presented and compared in an effort to explore the size of the chiral `regime', lattice spacing errors and quenching artefacts. While no run covers this whole range of effects the partial results indicate a picture of small lattice spacing errors, small quenching effects and only reaching the chiral regime at rather light quark masses.