Global analysis of proton elastic form factor data with two-photon exchange corrections

TL;DR

This paper provides a comprehensive analysis of proton elastic form factor data by incorporating two-photon exchange corrections, leading to more accurate extractions of the proton's electric and magnetic form factors across all measured momentum transfers.

Contribution

It introduces the first extraction of G_Ep and G_Mp that explicitly includes two-photon exchange corrections and their uncertainties, improving the accuracy of form factor measurements.

Findings

Corrected form factors show improved consistency between different measurement methods.

Angular dependence of cross sections suggests potential nonlinearities in epsilon.

Two-photon exchange effects are significant in precise form factor extraction.

Abstract

We use the world's data on elastic electron--proton scattering and calculations of two-photon exchange effects to extract corrected values of the proton's electric and magnetic form factors over the full Q^2 range of the existing data. Our analysis combines the corrected Rosenbluth cross section and polarization transfer data, and is the first extraction of G_Ep and G_Mp including explicit two-photon exchange corrections and their associated uncertainties. In addition, we examine the angular dependence of the corrected cross sections, and discuss the possible nonlinearities of the cross section as a function of epsilon.