Abstract
The double-polarization observable E was studied for the reaction γp → pω using the CEBAF Large Acceptance Spectrometer (CLAS) in Hall B at the Thomas Jefferson National Accelerator Facility and the longitudinally polarized frozen-spin target (FROST). The observable was measured from the charged decay mode of the meson, ω → π+π−π0, using a circularly polarized tagged-photon beam with energies ranging from the ω threshold at 1.1 to 2.3 GeV. A partial-wave analysis within the Bonn-Gatchina framework found dominant contributions from the 3/2+ partial wave near threshold, which is identified with the subthreshold N(1720)3/2+ nucleon resonance. To describe the entire data set, which consisted of ω differential cross sections and a large variety of polarization observables, further contributions from other nucleon resonances were found to be necessary. With respect to nonresonant mechanisms, π exchange in the t channel was found to remain small across the analyzed energy range, while Pomeron t-channel exchange gradually grew from the reaction threshold to dominate all other contributions above W ≈ 2 GeV.
Document Type
Article
Publication Date
12-28-2017
Digital Object Identifier (DOI)
https://doi.org/10.1103/PhysRevC.96.065209
Funding Information
This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Contract No. DE-AC05-06OR23177. This work was also supported by the U.S. National Science Foundation, the State Committee of Science of the Republic of Armenia, the Chilean Comisión Nacional de Investigación Científica y Tecnológica (CONICYT), the Italian Istituto Nazionale di Fisica Nucleare, the French Centre National de la Recherche Scientifique, the French Commissariat a l’Energie Atomique, the Scottish Universities Physics Alliance (SUPA), the United Kingdom’s Science and Technology Facilities Council, the National Research Foundation of Korea, the Deutsche Forschungsgemeinschaft (SFB/TR110), and the Russian Science Foundation under Grant No. 16-12-10267.
Repository Citation
Akbar, Z.; Roy, P.; Park, S.; Crede, V.; Anisovich, A. V.; Denisenko, I.; Klempt, E.; Nikonov, V. A.; Sarantsev, A. V.; Adhikari, K. P.; Adhikari, S.; Amaryan, M. J.; Anefalos Pereira, S.; Avakian, H.; Ball, J.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Boiarinov, S.; Briscoe, W. J.; Brock, J.; Brooks, W. K.; Burkert, V. D.; Cao, F. T.; Carlin, C.; Carman, D. S.; Celentano, A.; Charles, G.; Chetry, T.; Ciullo, G.; and Gohn, Wesley P., "Measurement of the Helicity Asymmetry E in ω → π+π−π0 Photoproduction" (2017). Physics and Astronomy Faculty Publications. 547.
https://uknowledge.uky.edu/physastron_facpub/547
Notes/Citation Information
Published in Physical Review C, v. 96, issue 6, 065209, p. 1-11.
©2017 American Physical Society
The copyright holder has granted permission for posting the article here.
Due to the large number of authors, only the first 30 and the authors affiliated with the University of Kentucky are listed in the author section above. For the complete list of authors, please download this article or visit: https://doi.org/10.1103/PhysRevC.96.065209
This group of authors is collectively known as the CLAS Collaboration.