Measurement of the Helicity Asymmetry E for the 𝛾p → p𝛑⁰ Reaction in the Resonance Region

Authors

C. W. Kim
N. Zachariou
M. Bashkanov
W. J. Briscoe
S. Fegan
V. L. Kashevarov
K. Nikonov
A. Sarantsev
A. Schmidt
I. I. Strakovsky
D. P. Watts
R. L. Workman
P. Achenbach
Z. Akbar
M. J. Amaryan, Old Dominion UniversityFollow
G. Angelini
W. R. Armstrong
H. Atac
L. Baashen
M. Zurek
et al.
The CLAS Collaboration

Document Type

Article

Publication Date

2023

DOI

10.1140/epja/s10050-023-01123-3

Publication Title

The European Physical Journal A

Volume

59

Issue

9

Pages

217 (1-12)

Abstract

The double-spin-polarization observable E for 𝛾^→ p^→ → p𝛑⁰ has been measured with the CEBAF Large Acceptance Spectrometer (CLAS) at photon beam energies E𝛾 from 0.367 to 2.173 GeV (corresponding to center-of-mass energies from 1.240 to 2.200 GeV) for pion center-of-mass angles, cos θ^c.m._𝛑⁰, between - 0.86 and 0.82. These new CLAS measurements cover a broader energy range and have smaller uncertainties compared to previous CBELSA data and provide an important independent check on systematics. These measurements are compared to predictions as well as new global fits from The George Washington University, Mainz, and Bonn-Gatchina groups. Their inclusion in multipole analyses will allow us to refine our understanding of the single-pion production contribution to the Gerasimov-Drell-Hearn sum rule and improve the determination of resonance properties, which will be presented in a future publication.

Rights

This article is licensed under a Creative Commons Attribution 4.0 International (CC BY 4.0) License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.

Data Availability

Article states: "This manuscript has associated data in a data repository [Author's comment: Numerical CLAS FROST E data are available in the SAID [58], CLAS [59] and University of York Pure databases [60]."

Original Publication Citation

Kim, C. W., Zachariou, N., Bashkanov, M., Briscoe, W. J., Fegan, S., Kashevarov, V. L., Nikonov, K., Sarantsev, A., Schmidt, A., Strakovsky, I. I., Watts, D. P., Workman, R. L., Achenbach, P., Akbar, Z., Amaryan, M. J., Angelini, G., Armstrong, W. R., Atac, H., Baashen, L., . . . Zurek, M. (2023). Measurement of the helicity asymmetry E for the 𝛾^→ p^→ → p𝛑⁰ reaction in the resonance region. The European Physical Journal A, 59(9), 1-12, Article 217. https://doi.org/10.1140/epja/s10050-023-01123-3

ORCID

0000-0003-2086-2807 (Hattawy), 0000-0002-1265-2212 (Hauenstein), 0000-0002-3598-4594 (Pandey)

Repository Citation

Kim, C. W.; Zachariou, N.; Bashkanov, M.; Briscoe, W. J.; Fegan, S.; Kashevarov, V. L.; Nikonov, K.; Sarantsev, A.; Schmidt, A.; Strakovsky, I. I.; Watts, D. P.; Workman, R. L.; Achenbach, P.; Akbar, Z.; Amaryan, M. J.; Angelini, G.; Armstrong, W. R.; Atac, H.; Baashen, L.; Zurek, M.; et al.; and The CLAS Collaboration, "Measurement of the Helicity Asymmetry E for the 𝛾p → p𝛑⁰ Reaction in the Resonance Region" (2023). Physics Faculty Publications. 822.
https://digitalcommons.odu.edu/physics_fac_pubs/822