Final Results of the GEp-III Experiment and the Status of the Proton Form Factors

TL;DR

This paper reports extended measurements of the proton's electric and magnetic form factors up to high momentum transfer, providing new data that refine the understanding of proton structure.

Contribution

It presents the final results of the GEp-III experiment, extending the Q^2 range of recoil polarization measurements and offering a comprehensive global fit of proton form factors.

Findings

Extended Q^2 coverage of form factor measurements to 8.5 GeV^2

Improved global fit of G_E^p and G_M^p data

Enhanced understanding of proton structure at high momentum transfer

Abstract

The recently published final results of experiment E04-108 in Jefferson Lab Hall C extend the recoil polarization measurements of the ratio of the proton electric and magnetic form factors to $Q^2 = 8.5$ GeV$^2$, an increase in $Q^2$ coverage of more than 50\%. A global fit of $G_E^p$ and $G_M^p$ to selected data for electron-proton elastic scattering cross sections and polarization observables is presented, illustrating the statistical impact of the new results.