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Cross sections for hard exclusive electroproduction of π + mesons on a hydrogen target

2007; Elsevier BV; Volume: 659; Issue: 3 Linguagem: Inglês

10.1016/j.physletb.2007.11.079

1873-2445

A. Airapetian, Н. Акопов, Z. Akopov, E. C. Aschenauer, W. Augustyniak, A. Avetissian, E. Avetissian, L. Barion, S. Belostotski, N. Bianchi, H.P. Blok, H. Böttcher, C. Bonomo, A. Borissov, V. Bryzgalov, J. Burns, M. Capiluppi, G. P. Capitani, E. Cisbani, G. Ciullo, M. Contalbrigo, P.F. Dalpiaz, W. Deconinck, R. De Leo, M. Demey, L. De Nardo, E. De Sanctis, M. Diefenthaler, P. Di Nezza, J. Dreschler, M. Düren, M. Ehrenfried, G. Elbakian, F. Ellinghaus, R. Fabbri, A. Fantoni, S. Frullani, D. Gabbert, G. Gapienko, В. А. Гапиенко, F. Garibaldi, G. Gavrilov, V. Gharibyan, F. Giordano, S. Gliske, H. Guler, C. Hadjidakis, D. Hasch, G. C. Hill, A. Hillenbrand, M. Hoek, I. Hristova, A. Ilyichev, Y. Imazu, A. Ivanilov, H. E. Jackson, S. Joosten, R. Kaiser, T. Keri, E. Kinney, A. Kisselev, M. Kopytin, В. А. Коротков, P. Kravchenko, V. G. Krivokhijine, L. Lagamba, R. Lamb, L. Lapikás, I. Lehmann, P. Lenisa, L. A. Linden-Levy, A. López Ruiz, W. Lorenzon, Shichao Lu, X.-G. Lu, D. Mahon, N. C. R. Makins, B. Mariański, H. Marukyan, C. A. Miller, Y. Miyachi, V. Muccifora, M. Murray, A. Mussgiller, E. Nappi, Y. Naryshkin, A. Nass, M. Negodaev, W.‐D. Nowak, L. L. Pappalardo, R. Pérez-Benito, N. Pickert, M. Raithel, P. E. Reimer, A. R. Reolon, C. Riedl, K. Rith, S. E. Rock, G. Rosner, A. Rostomyan, L. Rubáček, J. Rubin, D. Ryckbosch, Y. Salomatin, A. Schäfer, G. Schnell, K. P. Schüler, B. Seitz, C. Shearer, T.-A. Shibata, V. Shutov, M. Stancari, M. Statera, J. J. M. Steijger, H. Stenzel, J. Stewart, F. Stinzing, J. Streit, S. Taroian, E. Thomas, A. Trzciński, M. Tytgat, A. Vandenbroucke, P. B. van der Nat, G. van der Steenhoven, Y. Van Haarlem, C. Van Hulse, M. Varanda, D. Veretennikov, V. Vikhrov, I. Vilardi, Christian Vogel, S. Wang, S. Yaschenko, H. Ye, Z. Ye, S. Yen, W. Yu, D. Zeiler, B. Zihlmann, P. Żuprański,

High-Energy Particle Collisions Research

The exclusive electroproduction of π+ mesons was studied with the HERMES spectrometer at the DESY laboratory by scattering 27.6 GeV positron and electron beams off an internal hydrogen gas target. The virtual-photon cross sections were measured as a function of the Mandelstam variable t and the squared four momentum −Q2 of the exchanged virtual photon. A model calculation based on Generalized Parton Distributions is in fair agreement with the data at low values of |t| if power corrections are included. A model calculation based on the Regge formalism gives a good description of the magnitude and the t and Q2 dependences of the cross section.