Search for a two-photon exchange contribution to inclusive deep-inelastic scattering

Airapetian, A.; Akopov, N.; Akopov, Z.; Aschenauer, E.; Augustyniak, W.; Avakian, R.; Avetissian, A.; Avetisyan, E.; Ball, B.; Belostotski, S.; Bianchi, N.; Blok, H.; Böttcher, H.; Bonomo, C.; Borissov, A.; Bowles, J.; Bryzgalov, V.; Burns, J.; Capitani, G.; Cisbani, E.; Ciullo, Giuseppe; Contalbrigo, Marco; Ferretti, Paola; Deconinck, W.; Nardo, L. D.; Sanctis, E. D.; Diefenthaler, M.; Nezza, P. D.; Düren, M.; Ehrenfried, M.; Elbakian, G.; Ellinghaus, F.; Fabbri, R.; Fantoni, A.; Felawka, L.; Frullani, S.; Gabbert, D.; Gapienko, G.; Gapienko, V.; Garibaldi, F.; Gharibyan, V.; Giordano, Francesca; Gliske, S.; Hadjidakis, C.; Hartig, M.; Hasch, D.; Hill, G.; Hillenbrand, A.; Hoek, M.; Holler, Y.; Hristova, I.; Imazu, Y.; Ivanilov, A.; Jackson, H.; Jo, H.; Joosten, S.; Kaiser, R.; Karyan, G.; Keri, T.; Kinney, E.; Kisselev, A.; Korotkov, V.; Kozlov, V.; Kravchenko, P.; Lagamba, L.; Lamb, R.; Lapikás, L.; Lehmann, I.; Lenisa, Paolo; Ruiz, A. L.; Lorenzon, W.; Lu, X.; Lu, X.; Ma, B.; Mahon, D.; Makins, N.; Manfré, L.; Mao, Y.; Marianski, B.; de la Ossa, A. M.; Marukyan, H.; Miller, C.; Miyachi, Y.; Movsisyan, A.; Muccifora, V.; Murray, M.; Mussgiller, A.; Naryshkin, Y.; Nass, A.; Negodaev, M.; Nowak, W.; Pappalardo, Luciano Libero; Perez Benito, R.; Raithel, M.; Reimer, P.; Reolon, A.; Riedl, C.; Rith, K.; Rosner, G.; Rostomyan, A.; Rubin, J.; Ryckbosch, D.; Salomatin, Y.; Sanftl, F.; Schäfer, A.; Schnell, G.; Schüler, K.; Seitz, B.; Shibata, T.; Shutov, V.; Stancari, Michelle Dawn; Statera, Marco; Steffens, E.; Steijger, J.; Stenzel, H.; Stewart, J.; Stinzing, F.; Taroian, S.; Terkulov, A.; Trzcinski, A.; Tytgat, M.; Vandenbroucke, A.; der Nat, P. v.; Haarlem, Y. V.; Hulse, C. V.; Varanda, M.; Veretennikov, D.; Vikhrov, V.; Vilardi, I.; Wang, S.; Yaschenko, S.; Ye, H.; Ye, Z.; Yu, W.; Zeiler, D.; Zihlmann, B.; Zupranski, P.

doi:10.1016/j.physletb.2009.11.041

The transverse-target single-spin asymmetry for inclusive deep-inelastic scattering with effectively unpolarized electron and positron beams off a transversely polarized hydrogen target was measured, with the goal of searching for a two-photon exchange signal in the kinematic range 0.007<xB<0.9 and . In two separate regions and , and for both electron and positron beams, the asymmetries are found to be consistent with zero within statistical and systematic uncertainties, which are of order 10-3 for the asymmetries integrated over xB.