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Skorodko, T.; Bashkanov, M.; Bogoslawsky, D.; Calen, H.; Clement, H.; Doroshkevich, E.; Demiroers, L.; Ekstrom, C.; Fransson, K.; Gustafsson, L.; Hoistad, B.; Ivanov, G.; Jacewicz, M.; Jiganov, E.; Johansson, T.; Khakimova, O.; Keleta, S.; Koch, I.; Kren, F.; Kullander, S.; Kupsc, A.; Marciniewski, P.; Meier, R.; Morosov, B.; Pauly, C.; Petren, H.; Petukhov, Y.; Povtorejko, A.; Ruber, R. J. M. Y.; Schonning, K.; Scobel, W.; Shwartz, B.; Stepaniak, J.; Thörngren Engblom, Pia; Tikhomirov, V.; Wagner, G. J.; Wolke, M.; Yamamoto, A.; Zabierowski, J.; Zlomanczuk, J.
Physics letters. B, 2011, Letnik: 695, Številka: 1-4Journal Article
Exclusive measurements of the pp -> pp pi(0)pi(0) reaction have been performed at CELSIUS/WASA at energies from threshold up to T(p) = 1.3 GeV. Total and differential cross sections have been obtained. Here we concentrate on energies T(p) >= GeV. where the Delta Delta excitation becomes the leading process. No evidence is found for a significant ABC effect beyond that given by the conventional t-channel Delta Delta excitation. This holds also for the double-pionic fusion to the quasibound (2)He. The data are compared to model predictions, which are based on both pi- and rho-exchange. Total and differential cross sections are at variance with these predictions and call for a profound modification of the rho-exchange. A phenomenological modification allowing only a small rho-exchange contribution leads to a quantitative description of the data.
