Determination of two-photon exchange amplitudes from elastic electron-proton scattering data

TL;DR

This paper extracts two-photon exchange amplitudes from elastic electron-proton scattering data at Q^2 ≈ 2.5 GeV^2 and predicts the e^+ p / e^- p cross section ratio for upcoming experiments.

Contribution

It provides the first extraction of two-photon exchange amplitudes at a specific momentum transfer from existing data and predicts a measurable cross section ratio.

Findings

Extracted two-photon exchange amplitudes at Q^2 ≈ 2.5 GeV^2

Predicted e^+ p / e^- p elastic scattering cross section ratio

Provides data-driven insights for upcoming experiments

Abstract

Using the available cross section and polarization data for elastic electron-proton scattering, we provide an extraction of the two-photon exchange amplitudes at a common value of four-momentum transfer, around Q^2 = 2.5 GeV^2. This analysis also predicts the e^+ p / e^- p elastic scattering cross section ratio, which will be measured by forthcoming experiments.