U.S. Department of Energy Office of Scientific and Technical Information
Measurement of the helicity asymmetry $$$${\mathbb {E}}$$$$ for the $$$$\vec {\gamma }\vec {p} \rightarrow p \pi ^0$$$$ reaction in the resonance region: The CLAS Collaboration
Journal Article·· European Physical Journal. A, Hadrons and Nuclei (Online)
The double-spin-polarization observable $$$${\mathbb {E}}$$$$ for $$$$\vec {\gamma }\vec {p}\rightarrow p\pi ^0$$$$ has been measured with the CEBAF Large Acceptance Spectrometer (CLAS) at photon beam energies $$$$E_\gamma $$$$ from 0.367 to $$$$2.173~\textrm{GeV}$$$$ (corresponding to center-of-mass energies from 1.240 to $$$$2.200~\textrm{GeV}$$$$ ) for pion center-of-mass angles, $$$$\cos \theta _{\pi ^0}^{c.m.}$$$$ , between $$-$$ 0.86 and 0.82. These new CLAS measurements cover a broader energy range and have smaller uncertainties compared to previous CBELSA data and provide an important independent check on systematics. These measurements are compared to predictions as well as new global fits from The George Washington University, Mainz, and Bonn-Gatchina groups. Their inclusion in multipole analyses will allow us to refine our understanding of the single-pion production contribution to the Gerasimov-Drell-Hearn sum rule and improve the determination of resonance properties, which will be presented in a future publication.
Kim, C. W., et al. "Measurement of the helicity asymmetry $${\mathbb {E}}$$ for the $$\vec {\gamma }\vec {p} \rightarrow p \pi ^0$$ reaction in the resonance region: The CLAS Collaboration." European Physical Journal. A, Hadrons and Nuclei (Online), vol. 59, no. 9, Sep. 2023. https://doi.org/10.1140/epja/s10050-023-01123-3
Kim, C. W., Zachariou, N., Bashkanov, M., Briscoe, W. J., Fegan, S., Kashevarov, V. L., Nikonov, K., Sarantsev, A., Schmidt, A., Strakovsky, I. I., Watts, D. P., Workman, R. L., Achenbach, P., Akbar, Z., Amaryan, M. J., Angelini, G., Armstrong, W. R., Atac, H., ... Zurek, M. (2023). Measurement of the helicity asymmetry $${\mathbb {E}}$$ for the $$\vec {\gamma }\vec {p} \rightarrow p \pi ^0$$ reaction in the resonance region: The CLAS Collaboration. European Physical Journal. A, Hadrons and Nuclei (Online), 59(9). https://doi.org/10.1140/epja/s10050-023-01123-3
Kim, C. W., Zachariou, N., Bashkanov, M., et al., "Measurement of the helicity asymmetry $${\mathbb {E}}$$ for the $$\vec {\gamma }\vec {p} \rightarrow p \pi ^0$$ reaction in the resonance region: The CLAS Collaboration," European Physical Journal. A, Hadrons and Nuclei (Online) 59, no. 9 (2023), https://doi.org/10.1140/epja/s10050-023-01123-3
@article{osti_2006520,
author = {Kim, C. W. and Zachariou, N. and Bashkanov, M. and Briscoe, W. J. and Fegan, S. and Kashevarov, V. L. and Nikonov, K. and Sarantsev, A. and Schmidt, A. and Strakovsky, I. I. and others},
title = {Measurement of the helicity asymmetry $${\mathbb {E}}$$ for the $$\vec {\gamma }\vec {p} \rightarrow p \pi ^0$$ reaction in the resonance region: The CLAS Collaboration},
annote = {Abstract The double-spin-polarization observable $${\mathbb {E}}$$ E for $$\vec {\gamma }\vec {p}\rightarrow p\pi ^0$$ γ → p → → p π 0 has been measured with the CEBAF Large Acceptance Spectrometer (CLAS) at photon beam energies $$E_\gamma $$ E γ from 0.367 to $$2.173~\textrm{GeV}$$ 2.173 GeV (corresponding to center-of-mass energies from 1.240 to $$2.200~\textrm{GeV}$$ 2.200 GeV ) for pion center-of-mass angles, $$\cos \theta _{\pi ^0}^{c.m.}$$ cos θ π 0 c . m . , between $$-$$ - 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. },
doi = {10.1140/epja/s10050-023-01123-3},
url = {https://www.osti.gov/biblio/2006520},
journal = {European Physical Journal. A, Hadrons and Nuclei (Online)},
issn = {ISSN 1434-601X},
number = {9},
volume = {59},
place = {Germany},
publisher = {Springer Science + Business Media},
year = {2023},
month = {09}}
USDOE Office of Science (SC), Nuclear Physics (NP)
Grant/Contract Number:
SC0016583
OSTI ID:
2006520
Alternate ID(s):
OSTI ID: 2202972
Journal Information:
European Physical Journal. A, Hadrons and Nuclei (Online), Journal Name: European Physical Journal. A, Hadrons and Nuclei (Online) Journal Issue: 9 Vol. 59; ISSN 1434-601X
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