Abstract
The unpolarized and polarized Beam Charge Asymmetries (BCAs) of the \(\vec {e}^{\pm }p \rightarrow e^{\pm }p \gamma \) process off unpolarized hydrogen are discussed. The measurement of BCAs with the CLAS12 spectrometer at the Thomas Jefferson National Accelerator Facility, using polarized positron and electron beams at 10.6 GeV is investigated. This experimental configuration allows to measure azimuthal and t-dependences of the unpolarized and polarized BCAs over a large \((x_B,Q^2)\) phase space, providing a direct access to the real part of the Compton Form Factor (CFF) \({{\mathcal {H}}}\). Additionally, these measurements confront the Bethe-Heitler dominance hypothesis and eventual effects beyond leading twist. The impact of potential positron beam data on the determination of CFFs is also investigated within a local fitting approach of experimental observables. Positron data are shown to strongly reduce correlations between CFFs and consequently improve significantly the determination of \(\mathfrak {R}\mathrm{e} [{\mathcal {H}}]\).
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Data Availability Statement
This manuscript has no associated data or the data will not be deposited. [Authors’ comment: The present work involves only simulated pseudo-data.]
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Acknowledgements
This article is part of a project that has received funding from the European Union’s Horizon 2020 research and innovation program under agreement STRONG - 2020 - No 824093. It is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
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Communicated by Nicolas Alamanos.
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Burkert, V., Elouadrhiri, L., Girod, FX. et al. Beam charge asymmetries for deeply virtual Compton scattering off the proton. Eur. Phys. J. A 57, 186 (2021). https://doi.org/10.1140/epja/s10050-021-00474-z
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DOI: https://doi.org/10.1140/epja/s10050-021-00474-z