Nucleon electromagnetic form factors at high $Q^2$ from Wilson-clover fermions

TL;DR

This study computes nucleon electromagnetic form factors at high momentum transfer using lattice QCD with Wilson-clover fermions, achieving good agreement with experimental ratios but noting discrepancies in individual form factors.

Contribution

It provides high-$Q^2$ lattice QCD results for nucleon form factors using Wilson-clover fermions and advanced techniques to control excited state effects.

Findings

Good agreement with experimental ratios $G_E/G_M$ and $F_2/F_1$.

Discrepancies observed in individual form factors $F_1$ and $F_2$.

Analysis of systematic uncertainties.

Abstract

We present results on the nucleon electromagnetic form factors from Lattice QCD at momentum transfer up to about $12$~GeV$^2$. We analyze two gauge ensembles with the Wilson-clover fermion action, a lattice spacing of $a\approx 0.09$~fm and pion masses $m_\pi\approx 170$~MeV and $m_\pi\approx 280$~MeV. In our analysis we employ momentum smearing as well as a set of techniques to investigate excited state effects. Good agreement with experiment and phenomenology is found for the ratios $G_E/G_M$ and $F_2/F_1$, whereas discrepancies are observed for the individual form factors $F_1$ and $F_2$. We discuss various systematics that may affect our calculation.