Abstract
Two-photon-exchange (TPE) contributions to elastic electron-proton scattering in the forward regime in leading logarithmic approximation in the momentum transfer are considered. The imaginary part of the TPE amplitude in the forward kinematics is related to the total photoabsorption cross section. The real part of the TPE amplitude is obtained from an unsubtracted fixed- dispersion relation. This allows a clean prediction of the real part of the TPE amplitude at forward angles with the leading term . Numerical estimates are comparable with or exceed the experimental precision in extracting the charge radius from the experimental data.
- Received 13 June 2014
- Revised 13 August 2014
DOI:https://doi.org/10.1103/PhysRevC.90.052201
©2014 American Physical Society