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Publication Date




Publication Title

The European Physical Journal A






217 (1-12)


The double-spin-polarization observable E for ๐›พโ†’ pโ†’ โ†’ p๐›‘โฐ has been measured with the CEBAF Large Acceptance Spectrometer (CLAS) at photon beam energies E๐›พ 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 ฮธc.m.๐›‘โฐ, 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.


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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 ๐›พโ†’ pโ†’ โ†’ p๐›‘โฐ reaction in the resonance region. The European Physical Journal A, 59(9), 1-12, Article 217.


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

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