First Measurement of Hard Exclusive π- Δ++ Electroproduction Beam-Spin Asymmetries off the Proton
DOI
10.1103/PhysRevLett.131.021901
Document Type
Journal Article
Publication Date
7-14-2023
Publication Title
Physical Review Letters
Volume
131
Issue
2
ISSN
319007
Abstract
The polarized cross-section ratio σLT′/σ0 from hard exclusive π-Δ++ electroproduction off an unpolarized hydrogen target has been extracted based on beam-spin asymmetry measurements using a 10.2 GeV/10.6 GeV incident electron beam and the CLAS12 spectrometer at Jefferson Lab. The study, which provides the first observation of this channel in the deep-inelastic regime, focuses on very forward-pion kinematics in the valence regime, and photon virtualities ranging from 1.5 GeV2 up to 7 GeV2. The reaction provides a novel access to the d-quark content of the nucleon and to p→Δ++ transition generalized parton distributions. A comparison to existing results for hard exclusive π+n and π0p electroproduction is provided, which shows a clear impact of the excitation mechanism, encoded in transition generalized parton distributions, on the asymmetry.
Open Access
Hybrid_Gold
Repository Citation
Diehl, S., Trotta, N., Joo, K., Achenbach, P., Akbar, Z., Armstrong, W., Atac, H., Avakian, H., Baashen, L., Baltzell, N., Barion, L., Bashkanov, M., Battaglieri, M., Bedlinskiy, I., Benmokhtar, F., Bianconi, A., Biselli, A., Bossù, F., & Brinkmann, K. (2023). First Measurement of Hard Exclusive π- Δ++ Electroproduction Beam-Spin Asymmetries off the Proton. Physical Review Letters, 131 (2). https://doi.org/10.1103/PhysRevLett.131.021901