First CLAS12 Measurement of Deeply Virtual Compton Scattering Beam-Spin Asymmetries in the Extended Valence Region

Abstract

Deeply virtual Compton scattering (DVCS) allows one to probe generalized parton distributions describing the 3D structure of the nucleon. We report the first measurement of the DVCS beam-spin asymmetry using the CLAS12 spectrometer with a 10.2 and 10.6 GeV electron beam scattering from unpolarized protons. The results greatly extend the Q2 and Bjorken-x phase space beyond the existing data in the valence region and provide 1600 new data points measured with unprecedented statistical uncertainty, setting new, tight constraints for future phenomenological studies.

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Funding Information: We acknowledge the outstanding efforts of the staff of the Accelerator, the Nuclear Physics Division, Hall B, and the Detector Support Group at JLab that have contributed to the design, construction, installation, and operation of the CLAS12 detector. We thank Maurizio Ungaro for his contributions in the CLAS12 simulations. We also thank the CLAS Collaboration for staffing shifts and taking high quality data. This work was supported by the U.S. Department of Energy under JSA/DOE Award No. DE-AC05-06OR23177. This work was also supported in part by the U.S. National Science Foundation, State Committee of Science of the Republic of Armenia, Chilean Agencia Nacional de Investigación y Desarrollo, Italian Istituto Nazionale di Fisica Nucleare, French Centre National de la Recherche Scientifique, French Commissariat a l’Energie Atomique, Scottish Universities Physics Alliance (SUPA), United Kingdom Science and Technology Facilities Council (STFC), National Research Foundation of Korea, and Deutsche Forschungsgemeinschaft (DFG). This research was funded in part by the French Agence Nationale de la Recherche Contract No. 37. This work was supported as well by the EU Horizon 2020 Research and Innovation Program under the Marie Sklodowska-Curie Grant Agreement No. 101003460 and the Ile-de-France region via the Blaise Pascal Chair of International Excellence. This work has been funded by the U.K. Science and Technology Facilities Council under Grants No. ST/P004458/1 and No. ST/V00106X/1 and in part by the Chilean National Agency of Research and Development ANID PIA/APOYO AFB180002. Publisher Copyright: © 2023 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.

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