Form factor ratio from unpolarized elastic electron proton scattering

TL;DR

This paper reanalyzes unpolarized electron-proton scattering data to extract the electric to magnetic form factor ratio, providing more reliable insights and addressing discrepancies in proton form factor behavior.

Contribution

It introduces a robust analysis method for form factor ratios from unpolarized data and clarifies their consistency with polarized measurements.

Findings

Form factor ratio is a reliable observable.

Results are compatible with polarized scattering data.

Provides constraints on kinematic regions for form factor extraction.

Abstract

A reanalysis of unpolarized electron-proton elastic scattering data is done in terms of the electric to magnetic form factor squared ratio. This observable is in principle more robust against experimental correlations and global normalizations. The present analysis shows indeed that it is a useful quantity that contains reliable and coherent information. The comparison with the ratio extracted from the measurement of the longitudinal to transverse polarization of the recoil proton in polarized electron-proton scattering shows that the results are compatible within the experimental errors. Limits are set on the kinematics where the physical information on the form factors can be safely extracted. The results presented in this work bring a decisive piece of information to the controversy on the deviation of the proton form factors from the dipole dependence.