Nucleon electromagnetic form factors from lattice QCD

TL;DR

This paper discusses recent lattice QCD calculations of nucleon electromagnetic form factors, highlighting progress in extrapolating to physical quark masses and comparing with experimental data.

Contribution

It presents new lattice QCD results for nucleon form factors using advanced extrapolation techniques to reach the physical quark mass limit.

Findings

Good agreement with experimental form factors below 1 GeV$^2$

Progress in extrapolating lattice data to the chiral limit

Enhanced understanding of nucleon structure from lattice QCD

Abstract

It is imperative that lattice QCD serve to develop our understanding of hadron structure and, where possible, to guide the interpretation of experimental data. There is now a great deal of effort directed at the calculation of the electroweak form factors of the nucleon, where for example, measurements at Jefferson Laboratory have recently revealed surprising behaviour in the ratio $G_E/G_M$. While, for the present, calculations within the framework of lattice QCD are limited to relatively large quark mass, there has been considerable progress in our understanding of how to extrapolate to the chiral limit. Here we report the results of the application of these techniques to the most recent form factor data from the QCDSF Collaboration. The level of agreement with all of the form factors, for $Q^2$ below 1 GeV$^2$, is already impressive.