The photoproduction of ω mesons off the proton has been studied in the reaction γp → pω using the CEBAF Large Acceptance Spectrometer (CLAS) and the frozen-spin target in Hall B at the Thomas Jefferson National Accelerator Facility. For the first time, the target asymmetry T has been measured in photoproduction from the decay ω → π+π−π0, using a transversely polarized target with energies ranging from just above the reaction threshold up to 2.8 GeV. Significant nonzero values are observed for these asymmetries, reaching about 30–40% in the third-resonance region. New measurements for the photon-beam asymmetry Σ are also presented, which agree well with previous CLAS results and extend the world database up to 2.1 GeV. These data and additional ω photoproduction observables from CLAS were included in a partial-wave analysis within the Bonn-Gatchina framework. Significant contributions from s-channel resonance production were found in addition to t-channel exchange processes.
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This material is based upon work supported by the US Department of Energy, Office of Science, Office of Nuclear Physics, under Contract No. DE-AC05-06OR23177. The group at Florida State University acknowledges additional support from the US Department of Energy, Office of Science, Office of Nuclear Physics, under Contract No. DE-FG02-92ER40735. This work was also supported by the US National Science Foundation, the State Committee of Science of Republic of Armenia, the Chilean Comisión Nacional de Investigación Cientifica 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, and the National Research Foundation of Korea, the Deutsche Forschungsgemeinschaft (DFG) (SFB/TR110), and the Russian Science Foundation (RSF) under Grant No. 16-12-10267.
See Supplemental Material at http://link.aps.org/supplemental/10.1103/PhysRevC.97.055202 for the numerical values of the presented data.
Roy, P.; Akbar, Z.; Park, S.; Crede, V.; Anisovich, A. V.; Denisenko, I.; Klempt, E.; Nikonov, V. A.; Sarantsev, A. V.; Adhikari, K. P.; Adhikari, S.; Anefalos Pereira, S.; Ball, J.; Balossino, I.; Bashkanov, M.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A. S.; Boiarinov, S.; Briscoe, W. J.; Brock, J.; Brooks, W. K.; Burkert, V. D.; Carlin, C.; Carman, D. S.; Celentano, A.; Charles, G.; Chetry, T.; Ciullo, G.; and Gohn, Wesley P., "Measurement of the Beam Asymmetry Σ and the Target Asymmetry T in the Photoproduction of ω Mesons Off the Proton Using CLAS at Jefferson Laboratory" (2018). Physics and Astronomy Faculty Publications. 578.