Document Type


Publication Date




Publication Title

Physics Letters B.




138459 (1-6)


The new experimental measurements of beam spin asymmetry were performed for the deeply virtual exclusive π0 production in a wide kinematic region with the photon virtualities Q2 up to 6.6 GeV2and the Bjorken scaling variable 𝓍B in the valence regime. The data were collected by the CEBAF Large Acceptance Spectrometer (CLAS12) at Jefferson Lab with longitudinally polarized 10.6 GeV electrons scattered on an unpolarized liquid-hydrogen target. Sizable asymmetry values indicate a substantial contribution from transverse virtual photon amplitudes to the polarized structure functions. The interpretation of these measurements in terms of the Generalized Parton Distributions (GPDs) demonstrates their sensitivity to the chiral-odd GPD E¯T, which contains information on quark transverse spin densities in unpolarized and polarized nucleons and provides access to the nucleon's transverse anomalous magnetic moment. Additionally, the data were compared to a theoretical model based on a Regge formalism that was extended to the high photon virtualities.


© 2024 The Authors.

This article is published under a Creative Commons Attribution 4.0 International (CC BY 4.0) License.

Data Availability

Article states: Data will be made available on request.

Original Publication Citation

Kim, A., Diehl, S., Joo, K., Kubarovsky, V., Achenbach, P., Akbar, Z., Alvarado, J. S., Armstrong, W. R., Atac, H., Avakian, H., Ayerbe Gayoso, C., Barion, L., Battaglieri, M., Bedlinskiy, I., Benkel, B., Bianconi, A., Biselli, A. S., Bondi, M., Bossù, F., . . . Zurek, M. (2024). Beam spin asymmetry measurements of deeply virtual π0 production with CLAS12. Physics Letters B, 849, 1-6, Article 138459.


0000-0003-2086-2807 (Hattawy), 0000-0002-1265-2212 (Hauenstein), 0000-0003-2243-6836 (Kuhn), 0000-0002-3598-4594 (Pandey), 0000-0001-6345-2360 (Poudel)

Kuhn-2024-BeamSpinAsymmetrySupplemental.pdf (132 kB)
Supplemental Material