Physical Review C
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.
Original Publication Citation
Akbar, Z., Roy, P., Park, S., Crede, V., Anisovich, A. V., Denisenko, I., . . . Zhao, Z. W. (2017). Measurement of the helicity asymmetry e in ω→π+π-π0 photoproduction. Physical Review C, 96(6), 065209. doi:10.1103/PhysRevC.96.065209
Akbar, Z.; Roy, P.; Park, S.; Crede, V.; Anisovich, A. V.; Denisenko, I.; Klempt, E.; Nikonov, V. A.; Sarantsev, A. V.; Adhikari, K. P.; Amaryan, M. J.; Charles, G.; Klein, A.; Prok, Y.; Zhang, J.; and Zhao, Z. W., "Measurement of the Helicity Asymmetry e in ω→π+πˉπᵒ Photoproduction" (2017). Physics Faculty Publications. 113.