Measurement of target and double-spin asymmetries for the e p → eπ+(n) reaction in the nucleon resonance region at low Q2

Zheng, X. et al. (2016) Measurement of target and double-spin asymmetries for the e p → eπ+(n) reaction in the nucleon resonance region at low Q2. Physical Review C, 94(4), 045206. (doi: 10.1103/PhysRevC.94.045206)

Abstract

We report measurements of target- and double-spin asymmetries for the exclusive channel ep → eπ+(n) in the nucleon resonance region at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). These asymmetries were extracted from data obtained using a longitudinally polarized NH3 target and a longitudinally polarized electron beam with energies 1.1, 1.3, 2.0, 2.3, and 3.0 GeV. The new results are consistent with previous CLAS publications but are extended to a low Q2 range from 0.0065 to 0.35 (GeV/c) 2. The Q2 access was made possible by a custom-built Cherenkov detector that allowed the detection of electrons for scattering angles as low as 6◦. These results are compared with the unitary isobar models JANR and MAID, the partial-wave analysis prediction from SAID, and the dynamic model DMT. In many kinematic regions our results, in particular results on the target asymmetry, help to constrain the polarization-dependent components of these models.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Murdoch, Mr Gavin and 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
• Authors: Zheng, X., Adhikari, K. P., Bosted, P., Deur, A., Drozdov, V., El Fassi, L., Kang, H., Kovacs, K., Kuhn, S., Long, E., Phillips, S. K., Ripani, M., Slifer, K., Smith, L. C., Adikaram, D., Akbar, Z., Amaryan, M. J., Anefalos Pereira, S., Asryan, G., Avakian, H., Badui, R. A., Ball, J., Baltzell, N. A., Battaglieri, M., Batourine, V., Bedlinskiy, I., Biselli, A. S., Briscoe, W. J., Bültmann, S., Burkert, V. D., Carman, D. S., Celentano, A., Chandavar, S., Charles, G., Chen, J.-P., Chetry, T., Choi, S., Ciullo, G., Clark, L., Colaneri, L., Cole, P. L., Compton, N., Contalbrigo, M., Crede, V., D'Angelo, A., Dashyan, N., De Vita, R., De Sanctis, E., Djalali, C., Dodge, G. E., Dupre, R., Egiyan, H., El Alaoui, A., Elouadrhiri, L., Eugenio, P., Fanchini, E., Fedotov, G., Fersch, R., Filippi, A., Fleming, J. A., Gevorgyan, N., Ghandilyan, Y., Gilfoyle, G. P., Giovanetti, K. L., Girod, F. X., Gleason, C., Golovach, E., Gothe, R. W., Griffioen, K. A., Guidal, M., Guler, N., Guo, L., Hanretty, C., Harrison, N., Hattawy, M., Hicks, K., Holtrop, M., Hughes, S. M., Ilieva, Y., Ireland, D.G., Ishkhanov, B. S., Isupov, E. L., Jenkins, D., Jiang, H., Jo, H. S., Joosten, S., Keller, D., Khachatryan, G., Khandaker, M., Kim, A., Kim, W., Klein, F. J., Kubarovsky, V., Lanza, L., Lenisa, P., Livingston, K., MacGregor, I.J.D., Markov, N., McKinnon, B., Mirazita, M., Mokeev, V., Movsisyan, A., Munevar, E., Munoz Camacho, C., Murdoch, G., Nadel-Turonski, P., Net, L. A., Ni, A., Niccolai, S., Niculescu, G., Niculescu, I., Osipenko, M., Ostrovidov, A. I., Paolone, M., Paremuzyan, R., Park, K., Pasyuk, E., Peng, P., Pisano, S., Pogorelko, O., Price, J. W., Puckett, A. J. R., Raue, B. A., Rizzo, A., Rosner, G., Rossi, P., Roy, P., Sabatié, F., Salgado, C., Schumacher, R. A., Sharabian, Y. G., Skorodumina, I., Smith, G. D., Sokhan, D., Sparveris, N., Stankovic, I., Strakovsky, I. I., Strauch, S., Taiuti, M., Tian, Y., Ungaro, M., Voskanyan, H., Voutier, E., Walford, N. K., Watts, D. P., Wei, X., Weinstein, L. B., Wood, M. H., Zachariou, N., Zhang, J., and Zonta, I.
• 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: 19 October 2016
• Copyright Holders: Copyright © 2016 American Physical Society
• First Published: First published in Physical Review C 94(4):045206
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
65308	2	Glasgow nuclear physics consolidated grant	David Ireland	Science & Technologies Facilities Council (STFC)	ST/L005719/1	S&E P&A - PHYSICS & ASTRONOMY