Measurement of the helicity asymmetry E in ω → π+π−π0 photoproduction

Akbar, Z. et al. (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)

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.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Sokhan, Dr Daria and McKinnon, Dr Bryan and Ireland, Professor David and Clark, Ms Louise and Livingston, Dr Kenneth and MacGregor, Professor Douglas and Rosner, Professor Guenther and Protopopescu, Dr Dan
• Authors: 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., Clark, L., Cole, P. L., Contalbrigo, M., Cortes, O., D'Angelo, A., Dashyan, N., De Vita, R., De Sanctis, E., Deur, A., Djalali, C., Dugger, M., Dupre, R., Egiyan, H., El Fassi, L., Eugenio, P., Fedotov, G., Fersch, R., Filippi, A., Fradi, A., Garcon, M., Gevorgyan, N., Giovanetti, K. L., Girod, F. X., Gleason, C., Gohn, W., Golovatch, E., Gothe, R. W., Griffioen, K. A., Guidal, M., Guo, L., Hafidi, K., Hakobyan, H., Hanretty, C., Harrison, N., Hattawy, M., Heddle, D., Hicks, K., Hollis, G., Holtrop, M., Ireland, D.G., Ishkhanov, B. S., Isupov, E. L., Jenkins, D., Joosten, S., Keith, C. D., Keller, D., Khachatryan, G., Khachatryan, M., Khandaker, M., Kim, A., Kim, W., Klein, A., Klein, F. J., Kubarovsky, V., Lanza, L., Livingston, K., MacGregor, I.J.D., Markov, N., McKinnon, B., Meekins, D. G., Mineeva, T., Mokeev, V., Movsisyan, A., Munoz Camacho, C., Nadel-Turonski, P., Niccolai, S., Osipenko, M., Ostrovidov, A. I., Paolone, M., Paremuzyan, R., Park, K., Pasyuk, E., Phelps, W., Pogorelko, O., Price, J. W., Prok, Y., Protopopescu, D., Raue, B. A., Ripani, M., Ritchie, B. G., Rizzo, A., Rosner, G., Sabatié, F., Salgado, C., Schumacher, R. A., Sharabian, Y. G., Skorodumina, I., Smith, G. D., Sober, D. I., Sokhan, D., Sparveris, N., Stepanyan, S., Strakovsky, I. I., Strauch, S., Taiuti, M., Ungaro, M., Voskanyan, H., Voutier, E., Wei, X., Wood, M. H., Zachariou, N., Zana, L., Zhang, J., and Zhao, Z. W.
• College/School: College of Science and Engineering > School of Physics and Astronomy
• Journal Name: Physical Review C
• Publisher: American Physical Society
• ISSN: 0556-2813
• ISSN (Online): 1089-490X
• Published Online: 28 December 2017
• Copyright Holders: Copyright © 2017 American Physical Society
• First Published: First published in Physical Review C 96(6):065209
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher