501. First measurement of the helicity asymmetry $E$ in $\eta$ photoproduction on the proton
- Author
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Senderovich, I., Morrison, B. T., Dugger, M., Ritchie, B. G., Pasyuk, E., Tucker, R., Brock, J., Carlin, C., Keith, C. D., Meekins, D. G., Seely, M. L., R, D., D, M., Collins, P., Adhikari, K. P., Adikaram, D., Akbar, Z., Anderson, M. D., Pereira, S. Anefalos, Badui, R. A., Ball, J., Baltzell, N. A., Battaglieri, M., Batourine, V., Bedlinskiy, I., Biselli, A. S., Boiarinov, S., Briscoe, W. J., Brooks, W. K., Burkert, V. D., Carman, D. S., Celentano, A., Chandavar, S., Charles, G., Colaneri, L., Cole, P. L., Contalbrigo, M., Cortes, O., Crede, V., D'Angelo, A., Dashyan, N., De Vita, R., De Sanctis, E., Deur, A., Djalali, C., Dupre, R., Egiyan, H., Alaoui, A. El, Fassi, L. El, Fradi, A., Elouadrhiri, L., Eugenio, P., Fedotov, G., Fegan, S., Filippi, A., Fleming, J. A., Garillon, B., Ghandilyan, Y., Gilfoyle, G. P., Giovanetti, K. L., Girod, F. -X., Glazier, D. I., Goetz, J. T., Gohn, W., Golovatch, E., Gothe, R. W., Griffioen, K. A., Guidal, M., Guo, L., Hafidi, K., Hakobyan, H., Hanretty, C., Hattawy, M., Hicks, K., Ho, D., Holtrop, M., Hughes, S. M., Ilieva, Y., Ireland, D. G., Ishkhanov, B. S., Jenkins, D., Jiang, H., Jo, H. S., Joo, K., Joosten, S., Keller, D., Khachatryan, G., Khandaker, M., Kim, A., Klein, F. J., Kubarovsky, V., Kunkel, M. C., Lenisa, P., Livingston, K., Lu, H. Y., MacGregor, I. J. D., Mattione, P., McKinnon, B., Meyer, C. A., Mineeva, T., Mokeev, V., Montgomery, R. A., Movsisyan, A., Camacho, C. Munoz, Nadel-Turonski, P., Net, L. A., Niccolai, S., Niculescu, G., Niculescu, I., Osipenko, M., Park, K., Park, S., Peng, P., Phelps, W., Pisano, S., Pogorelko, O., Price, J. W., Prok, Y., Puckett, A. J. R., Ripani, M., Rizzo, A., Rosner, G., Roy, P., Sabatie, F., Salgado, C., Schott, D., Schumacher, R. A., Seder, E., Simonyan, A., Skorodumina, Iu., Smith, G. D., Sober, D. I., Sokhan, D., Sparveris, N., Stepanyan, S., Stoler, P., Strakovsky, I. I., Strauch, S., Sytnik, V., Tian, Ye, Ungaro, M., Voskanyan, H., Voutier, E., Walford, N. K., Wei, X., Wood, M. H., Zachariou, N., Zana, L., Zhang, J., Zhao, Z. W., and Zonta, I.
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Nuclear Experiment - Abstract
Results are presented for the first measurement of the double-polarization helicity asymmetry E for the $\eta$ photoproduction reaction $\gamma p \rightarrow \eta p$. Data were obtained using the FROzen Spin Target (FROST) with the CLAS spectrometer in Hall B at Jefferson Lab, covering a range of center-of-mass energy W from threshold to 2.15 GeV and a large range in center-of-mass polar angle. As an initial application of these data, the results have been incorporated into the J\"ulich model to examine the case for the existence of a narrow $N^*$ resonance between 1.66 and 1.70 GeV. The addition of these data to the world database results in marked changes in the predictions for the E observable using that model. Further comparison with several theoretical approaches indicates these data will significantly enhance our understanding of nucleon resonances.
- Published
- 2015
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