E-viri
PDF
Recenzirano
Odprti dostop
-
Clement, H.; Bashkanov, M.; Bargholtz, C.; Bogoslawsky, D.; Calen, H.; Cappellaro, F.; Demiroers, L.; Doroshkevich, E.; Duniec, D.; Ekström, C.; Franssen, K.; Geren, L.; Gustafsson, L.; Höistad, B.; Ivanov, G.; Jacewicz, M.; Jiganov, E.; Johansson, T.; Kaskulov, M.; Khakimova, O.; Keleta, S.; Koch, I.; Kren, F.; Kullander, S.; Kupść, A.; Kuznetsov, A.; Lindberg, K.; Marciniewski, P.; Meier, R.; Morosov, B.; Pauly, C.; Petterson, H.; Petukhov, Y.; Povtorejko, A.; Pricking, A.; Schönning, K.; Scobel, W.; Shwartz, B.; Skorodko, T.; Sopov, V.; Stepeniak, J.; Tegner, P.-E.; Thörngren-Engblom, P.; Tikhomirov, V.; Wagner, G.J.; Wolke, M.; Yamamoto, A.; Zabierowski, J.; Zartova, I.; Złomanczuk, J.
Progress in particle and nuclear physics, 07/2008, Letnik: 61, Številka: 1Journal Article
The ABC effect–an intriguing low-mass enhancement in the π π invariant mass spectrum–is known from inclusive measurements of two-pion production in nuclear fusion reactions. First exclusive measurements carried out at CELSIUS-WASA for the fusion reactions leading to d or 3He reveal this effect to be a σ -channel phenomenon associated with the formation of a Δ Δ system in the intermediate state and combined with a resonance-like behavior in the total cross-section. Together with the observation that the differential distributions do not change in shape over the resonance region the features fulfill the criteria of an isoscalar s-channel resonance in p n and N N π π systems, if the two emitted nucleons are bound. It obviously is robust enough to survive in nuclei as a dibaryonic resonance configuration. In this context also the phenomenon of N Δ resonances is reexamined.
