Separation of contributions from deeply virtual Compton scattering and its interference with the Bethe--Heitler process in measurements on a hydrogen target

TL;DR

This paper analyzes hard exclusive leptoproduction of real photons from an unpolarized proton to separate contributions from deeply virtual Compton scattering and its interference with the Bethe--Heitler process, enhancing understanding of generalized parton distributions.

Contribution

It introduces a method to disentangle DVCS and Bethe--Heitler contributions in experimental data, providing more precise asymmetry measurements related to generalized parton distributions.

Findings

Successful separation of DVCS and Bethe--Heitler contributions

Most precise measurement of beam charge dependence

Identification of correlated asymmetry dependences on kinematic variables

Abstract

Hard exclusive leptoproduction of real photons from an unpolarized proton target is studied in an effort to elucidate generalized parton distributions. The data accumulated during the years 1996--2005 with the HERMES spectrometer are analyzed to yield asymmetries with respect to the combined dependence of the cross section on beam helicity and charge, thereby revealing previously unseparated contributions from deeply virtual Compton scattering and its interference with the Bethe--Heitler process. The integrated luminosity is sufficient to show correlated dependences on two kinematic variables, and provides the most precise determination of the dependence on only the beam charge.