Electroexcitation of the Roper resonance for 1.7 Q(2) en pi(+)

I. G. Aznauryan, V. D. Burkert, W. Kim, K. Park, G. Adams, M. J. Amaryan, P. Ambrozewicz, M. Anghinolfi, G. Asryan, H. Avakian, H. Bagdasaryan, N. Baillie, J. P. Ball, N. A. Baltzell, S. Barrow, V. Batourine, M. Battaglieri, I. Bedlinskiy, M. Bektasoglu, M. BellisN. Benmouna, B. L. Berman, A. S. Biselli, L. Blaszczyk, B. E. Bonner, C. Bookwalter, S. Bouchigny, S. Boiarinov, R. Bradford, D. Branford, W. J. Briscoe, W. K. Brooks, S. Bueltmann, C. Butuceanu, J. R. Calarco, S. L. Careccia, D. S. Carman, L. Casey, A. Cazes, S. Chen, L. Cheng, P. L. Cole, P. Collins, P. Coltharp, D. Cords, P. Corvisiero, D. Crabb, V. Crede, J. P. Cummings, D. Dale, N. Dashyan, R. De Masi, R. De Vita, E. De Sanctis, P. V. Degtyarenko, H. Denizli, L. Dennis, A. Deur, S. Dhamija, K. V. Dharmawardane, K. S. Dhuga, R. Dickson, C. Djalali, G. E. Dodge, J. Donnelly, D. Doughty, M. Dugger, S. Dytman, O. P. Dzyubak, H. Egiyan, K. S. Egiyan, L. El 05 Fassi, L. Elouadrhiri, P. Eugenio, R. Fatemi, G. Fedotov, G. Feldman, R. J. Feuerbach, T. A. Forest, A. Fradi, H. Funsten, M. Y. Gabrielyan, M. Garcon, G. Gavalian, N. Gevorgyan, G. P. Gilfoyle, K. L. Giovanetti, F. X. Girod, J. T. Goetz, W. Gohn, E. Golovatch, A. Gonenc, C. I. O. Gordon, R. W. Gothe, L. Graham, K. A. Griffioen, M. Guidal, M. Guillo, N. Guler, L. Guo, V. Gyurjyan, C. Hadjidakis, K. Hafidi, K. Hafnaoui, H. Hakobyan, R. S. Hakobyan, C. Hanretty, J. Hardie, N. Hassall, D. Heddle, F. W. Hersman, K. Hicks, I. Hleiqawi, M. Holtrop, C. E. Hyde, Y. Ilieva, D. G. Ireland, B. S. Ishkhanov, E. L. Isupov, M. M. Ito, D. Jenkins, H. S. Jo, J. R. Johnstone, K. Joo, H. G. Juengst, N. Kalantarians, D. Keller, J. D. Kellie, M. Khandaker, K. Y. Kim, A. Klein, F. J. Klein, A. V. Klimenko, M. Kossov, Z. Krahn, L. H. Kramer, V. Kubarovsky, J. Kuhn, S. E. Kuhn, S. V. Kuleshov, V. Kuznetsov, J. Lachniet, J. M. Laget, J. Langheinrich, D. Lawrence, T. Lee, Ji Li, A. C. S. Lima, K. Livingston, H. Y. Lu, K. Lukashin, M. MacCormick, N. Markov, P. Mattione, S. McAleer, B. McKinnon, J. W. C. McNabb, B. A. Mecking, S. Mehrabyan, J. J. Melone, M. D. Mestayer, C. A. Meyer, T. Mibe, K. Mikhailov, R. Minehart, M. Mirazita, R. Miskimen, V. Mokeev, L. Morand, B. Moreno, K. Moriya, S. A. Morrow, M. Moteabbed, J. Mueller, E. Munevar, G. S. Mutchler, P. Nadel-Turonski, R. Nasseripour, S. Niccolai, G. Niculescu, I. Niculescu, B. B. Niczyporuk, M. R. Niroula, R. A. Niyazov, M. Nozar, G. V. O'Rielly, M. Osipenko, A. I. Ostrovidov, S. Park, E. Pasyuk, C. Paterson, S. Anefalos Pereira, S. A. Philips, J. Pierce, N. Pivnyuk, D. Pocanic, O. Pogorelko, E. Polli, I. Popa, S. Pozdniakov, B. M. Preedom, J. W. Price, Y. Prok, D. Protopopescu, L. M. Qin, B. A. Raue, G. Riccardi, G. Ricco, M. Ripani, B. G. Ritchie, G. Rosner, P. Rossi, D. Rowntree, P. D. Rubin, F. Sabatie, M. S. Saini, J. Salamanca, C. Salgado, J. P. Santoro, V. Sapunenko, D. Schott, R. A. Schumacher, V. S. Serov, Y. G. Sharabian, D. Sharov, J. Shaw, N. V. Shvedunov, A. V. Skabelin, E. S. Smith, L. C. Smith, D. I. Sober, D. Sokhan, A. Stavinsky, S. S. Stepanyan, S. Stepanyan, B. E. Stokes, P. Stoler, I. I. Strakovsky, S. Strauch, R. Suleiman, M. Taiuti, T. Takeuchi, D. J. Tedeschi, A. Tkabladze, S. Tkachenko, L. Todor, C. Tur, M. Ungaro, M. F. Vineyard, A. V. Vlassov, D. P. Watts, L. B. Weinstein, D. P. Weygand, M. Williams, E. Wolin, M. H. Wood, A. Yegneswaran, J. Yun, M. Yurov, L. Zana, B. Zhang, J. Zhang, B. Zhao, Z. W. Zhao

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Abstract

The helicity amplitudes of the electroexcitation of the Roper resonance are extracted for 1.7 < Q(2)< 4.5 GeV2 from recent high precision JLab-CLAS cross section and longitudinally polarized beam asymmetry data for pi(+) electroproduction on protons at W=1.15-1.69 GeV. The analysis is made using two approaches, dispersion relations and a unitary isobar model, which give consistent Q(2) behavior of the helicity amplitudes for the gamma(*)p -> N(1440)P-11 transition. It is found that the transverse helicity amplitude A(1/2), which is large and negative at Q(2)=0, becomes large and positive at Q(2)similar or equal to 2 GeV2, and then drops slowly with Q(2). The longitudinal helicity amplitude S-1/2, which was previously found from CLAS ep -> ep pi(0),en pi(+) data to be large and positive at Q(2)=0.4,0.65 GeV2, drops with Q(2). Available model predictions for gamma(*)p -> N(1440)P-11 allow us to conclude that these results provide strong evidence in favor of N(1440)P-11 as a first radial excitation of the 3q ground state. The results of the present paper also confirm the conclusion of our previous analysis for Q(2)< 1 GeV2 that the presentation of N(1440)P-11 as a q(3)G hybrid state is ruled out.

Original languageEnglish
Article number045209
Pages (from-to)-
Number of pages7
JournalPhysical Review C
Volume78
Issue number4
DOIs
Publication statusPublished - Oct 2008

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