ΔΔ excitation in proton–proton induced π0π0 production
- Skorodko, T.
- Bashkanov, M.
- Bogoslawsky, D.
- Calén, H.
- Clement, H.
- Doroshkevich, E.
- Demiroers, L.
- Ekström, C.
- Fransson, K.
- Gustafsson, L.
- Höistad, B.
- Ivanov, G.
- Jacewicz, M.
- Jiganov, E.
- Johansson, T.
- Khakimova, O.
- Keleta, S.
- Koch, I.
- Kren, F.
- Kullander, S.
- Kupść, A.
- Marciniewski, P.
- Meier, R.
- Morosov, B.
- Pauly, C.
- Petrén, H.
- Petukhov, Y.
- Povtorejko, A.
- Ruber, R.J.M.Y.
- Schönning, K.
- Scobel, W.
- Shwartz, B.
- Stepaniak, J.
- Thörngren-Engblom, P.
- Tikhomirov, V.
- Wagner, G.J.
- Wolke, M.
- Yamamoto, A.
- Zabierowski, J.
- Zlomanczuk, J.
DOIAbstract
AbstractExclusive measurements of the pp→ppπ0π0 reaction have been performed at CELSIUS/WASA at energies from threshold up to Tp=1.3 GeV. Total and differential cross sections have been obtained. Here we concentrate on energies Tp⩾1 GeV, where the ΔΔ excitation becomes the leading process. No evidence is found for a significant ABC effect beyond that given by the conventional t-channel ΔΔ excitation. This holds also for the double-pionic fusion to the quasibound 2He. The data are compared to model predictions, which are based on both π- and ρ-exchange. Total and differential cross sections are at variance with these predictions and call for a profound modification of the ρ-exchange. A phenomenological modification allowing only a small ρ-ex...