Regular Article - Theoretical Physics
Forward two-photon exchange in elastic lepton–proton scattering and hyperfine-splitting correction
Institut für Kernphysik and PRISMA Cluster of Excellence, Johannes Gutenberg Universität, Mainz, Germany
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Accepted: 14 July 2017
Published online: 4 August 2017
We relate the forward two-photon exchange (TPE) amplitudes to integrals of the inclusive lepton–proton scattering cross sections. These relations yield an alternative way for the evaluation of the TPE correction to hyperfine-splitting (HFS) in the hydrogen-like atoms with an equivalent to the standard approach (Iddings, Drell and Sullivan) result implying the Burkhardt–Cottingham sum rule. For evaluation of the individual effects (e.g., elastic contribution) our approach yields a distinct result. We compare both methods numerically on examples of the elastic contribution and the full TPE correction to HFS in electronic and muonic hydrogen.
© The Author(s), 2017