Beam–target helicity asymmetry E in K+Σ photoproduction on the neutron

The CLAS Collaboration, H Egiyan, M Ehrhart, A El Alaoui, P Eugenio, R. Fersch, A. Filippi, G. Gavalian, N. Gevorgyan, Y. Ghandilyan, G.P. Gilfoyle, F.X. Girod, W. Gohn, E. Golovatch, R.W. Gothe, K.A. Griffoen, M. Guidal, K. Hafidi, H. Hakobyan, M. HattawyD. Heddle, K. Hicks , D. Ho, M. Holtrop, Y. Ilieva, D.G. Ireland , B.S. Ishkanov, E.L. Isupov, D. Jenkins, H.S. Jo, K. Joo, S.J. Joosten, D. Keller, M. Khachatryan, A. Khanal, M. Khandaker , C.W. Kim, W. Kim, V. Kubarovsky, L. Lanza, M. Leali, P. Lenisa, K. Livingston, I.J.D. MacGregor , D. Marchand, N. Markov, L. Marsicano, V. Mascagna, M. Mayer, B. McKinnon, Z.E. Meziani, T. Mineeva, V. Mokeev, E. Munevar, C. Munoz Camacho, P. Nadal Turonski, T.R. O'Connell, M. Osipenko, A.I. Ostrovidov, M. Paolone, L.L. Pappalardo, K. Park , E. Pasyuk, P. Peng, W. Phelps, O. Pogorelko, J. Poudel, J.W. Price, Y. Prok, A.J.R. Puckett, B.R. Raue, M. Ripani, A. Rizzo, G. Rosner, C. Salgado, A. Schmidt, R.A. Schumacher, U. Shrestha, D. Sokhan, O. Soto, N. Sparveris, I.I. Strakovsky, S. Strauch, J.A. Tan, N. Tyler, M. Ungaro, L. Venturelli, H. Voskanyan, E. Voutier, N.K. Walford, C.S. Whisnant, M.H. Wood, J. Zhang, Z.W. Zhao

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We report a measurement of a beam–target double-polarisation observable (E) for the γ→n→(p)→K+Σ(p) reaction. The data were obtained impinging the circularly-polarised energy-tagged photon beam of Hall B at Jefferson Lab on a longitudinally-polarised frozen-spin hydrogen deuteride (HD) nuclear target. The E observable for an effective neutron target was determined for centre-of-mass energies 1.70≤W≤2.30 GeV, with reaction products detected over a wide angular acceptance by the CLAS spectrometer. These new double-polarisation data give unique constraints on the strange decays of excited neutron states. Inclusion of the new data within the Bonn-Gatchina theoretical model results in significant changes for the extracted photocouplings of a number of established nucleon resonances. Possible improvements in the PWA description of the experimental data with additional “missing” resonance states, including the N(2120)3/2 resonance, are also quantified.

Original languageEnglish
Article number135662
Number of pages7
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Early online date30 Jul 2020
Publication statusPublished - 10 Sept 2020

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