Overview of nucleon structure studies

TL;DR

This paper reviews recent advances in nucleon structure research, highlighting improved measurement techniques, the role of two-photon exchange, insights from form factors and lattice QCD, and the significance of generalized parton distributions.

Contribution

It provides a comprehensive overview of recent experimental and theoretical progress in understanding nucleon structure, emphasizing new measurement methods and the unifying role of generalized parton distributions.

Findings

Enhanced data quality from double polarization experiments

Insights into quark charge distributions within nucleons

Progress in lattice QCD calculations and resonance studies

Abstract

A brief overview of the recent activity in the measurement of the elastic electromagnetic proton and neutron form factors is presented. It is discussed how the quality of the data has been greatly improved by performing double polarization experiments, and the role of two-photon exchange processes will be highlighted. The spatial information on the quark charge distribibutions in the nucleon resulting from the form factors measurements will be discussed, as well as the steady rate of improvements made in the lattice QCD calculations. It is discussed how generalized parton distributions have emerged as a unifying theme in hadron physics linking the spatial densities extracted from form factors with the quark momentum distribution information residing in quark structure functions. The recent progress in the electromagnetic excitation of the $\Delta(1232)$ resonance will also briefly be discussed.