Measurement of double-spin asymmetries associated with deeply virtual Compton scattering on a transversely polarized hydrogen target

TL;DR

This paper reports measurements of double-spin asymmetries in deeply virtual Compton scattering on a transversely polarized hydrogen target, providing insights into the underlying generalized parton distributions.

Contribution

It presents the first measurement of specific double-spin asymmetries related to DVCS on a transversely polarized target, comparing results with GPD-based theoretical predictions.

Findings

Asymmetries are consistent with zero within uncertainties.

Results are compatible with existing GPD models.

Provides new experimental data for transverse target spin asymmetries.

Abstract

Double-spin asymmetries in exclusive electroproduction of real photons from a transversely polarized hydrogen target are measured with respect to the product of target polarization with beam helicity and beam charge, and with respect to the product of target polarization with beam helicity alone. The asymmetries arise from the deeply virtual Compton scattering process and its interference with the Bethe--Heitler process. They are related to the real part of the same combination of Compton form factors as that determining the previously published transverse target single-spin asymmetries through the imaginary part. The results for the double-spin asymmetries are found to be compatible with zero within the uncertainties of the measurement, and are not incompatible with the predictions of the only available GPD-based calculation.