Photoproduction of the ρ0 Meson on the Proton at Large Momentum Transfer

Battaglieri, M.; Anciant, E.; Anghinolfi, M.; De Vita, R.; Golovach, E.; Laget, J.; Mokeev, V.; Ripani, M.; Adams, G.; Amaryan, M.; Armstrong, D.; Asavapibhop, B.; Asryan, G.; Audit, G.; Auger, T.; Avakian, H.; Barrow, S.; Beard, K.; Bektasoglu, M.; Berman, B.; Bianchi, N.; Biselli, A.; Boiarinov, S.; Branford, D.; Briscoe, W.; Brooks, W.; Burkert, V.; Calarco, J.; Capitani, G.; Carman, D.; Carnahan, B.; Cazes, A.; Cetina, C.; Cole, P.; Coleman, A.; Cords, D.; Corvisiero, Pietro; Crabb, D.; Crannell, H.; Cummings, J.; Desanctis, E.; Degtyarenko, P.; Demirchyan, R.; Denizli, H.; Dennis, L.; Dharmawardane, K.; Dhuga, K.; Djalali, C.; Dodge, G.; Doughty, D.; Dragovitsch, P.; Dugger, M.; Dytman, S.; Eckhause, M.; Egiyan, H.; Egiyan, K.; Elouadrhiri, L.; Farhi, L.; Feuerbach, R.; Ficenec, J.; Forest, T.; Freyberger, A.; Frolov, V.; Funsten, H.; Gaff, S.; Gai, M.; Gilad, S.; Gilfoyle, G.; Giovanetti, K.; Griffioen, K.; Guidal, M.; Guillo, M.; Gyurjyan, V.; Hancock, D.; Hardie, J.; Heddle, D.; Hersman, F.; Hicks, K.; Hicks, R.; Holtrop, M.; Hyde Wright, C.; Ito, M.; Joo, K.; Kelley, J.; Khandaker, M.; Kim, W.; Klein, A.; Klein, F.; Klusman, M.; Kossov, M.; Kramer, L.; Kuang, Y.; Kuhn, S.; Lawrence, D.; Lucas, M.; Lukashin, K.; Major, R.; Manak, J.; Marchand, C.; Mcaleer, S.; Mccarthy, J.; Mcnabb, J.; Mecking, B.; Mestayer, M.; Meyer, C.; Mikhailov, K.; Minehart, R.; Mirazita, M.; Miskimen, R.; Muccifora, V.; Mueller, J.; Mutchler, G.; Napolitano, J.; Nelson, S.; Niczyporuk, B.; Niyazov, R.; O'Brien, J.; Opper, A.; Peterson, G.; Philips, S.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Polli, E.; Preedom, B.; Price, J.; Protopopescu, D.; Qin, L.; Raue, B.; Reolon, A.; Riccardi, G.; Ricco, Giovanni; Ritchie, B.; Ronchetti, F.; Rossi, P.; Rowntree, D.; Rubin, P.; Sabourov, K.; Salgado, C.; Sanzone, Marcella; Sapunenko, V.; Schumacher, R.; Serov, V.; Shafi, A.; Sharabian, Y.; Shaw, J.; Skabelin, A.; Smith, E.; Smith, T.; Smith, L.; Sober, D.; Spraker, M.; Stavinsky, A.; Stepanyan, S.; Stoler, P.; Taiuti, MAURO GINO; Taylor, S.; Tedeschi, D.; Todor, L.; Thompson, R.; Vineyard, M.; Vlassov, A.; Weinstein, L.; Weisberg, A.; Weller, H.; Weygand, D.; Whisnant, C.; Wolin, E.; Wood, M.; Yegneswaran, A.; Yun, J.; Zhang, B.; Zhao, J.; Zhou, Z.

doi:10.1103/PhysRevLett.87.172002

The differential cross section, dσ/dt, for ρ0 meson photoproduction on the proton above the resonance region was measured up to a momentum transfer -t = 5GeV2 using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The ρ0 channel was extracted from the measured two charged-pion cross sections by fitting the π+π- and pπ+ invariant masses. The low momentum transfer region shows the typical diffractive pattern expected from Reggeon exchange. The flatter behavior at large -t cannot be explained solely in terms of QCD-inspired two-gluon exchange models. The data indicate that other processes, like quark interchange, are important to fully describe ρ photoproduction.