Double Pion Production in the dd to αππ reaction
2008 (English)Doctoral thesis, monograph (Other academic)
The reaction dd → 4Heππ has been measured exclusively for the first time. The measurements were performed at Td = 712 MeV and Td = 1029 MeV, with the WASA detector assembly at CELSIUS (Uppsala-Sweden). The aim was to investigate a long standing puzzle, the so called ABC effect. This is a peculiar feature of double pion production in light nuclei collisions. In addition to confirming previous experimental observations in this regard, our results also reveal a strong angular dependence of the pions in the overall center of mass system as well as non-isotropic angular distribution of the low mass enhancement in the ππ invariant mass. The results are qualitatively reproduced by a theoretical model, according to which, the ABC effect is described as a result of kinematical enhancement in the independent production of the pion pairs from two parallel and independent NN → dπ reactions.
Place, publisher, year, edition, pages
Uppsala: Avdelningen för kärnfysik , 2008. , 107 p.
Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1104-2516 ; 77
Nuclear physics, ABC effect, double pion
Research subject Nuclear Physics
IdentifiersURN: urn:nbn:se:uu:diva-8926ISBN: 978-91-554-7231-3OAI: oai:DiVA.org:uu-8926DiVA: diva2:172240
2008-06-13, Polhemsalen, Ångström lab., Lägerhyddsv. 1, Uppsala, 10:00
Ströher, Hans, Prof.
Thörngren Engblom, Pia, Ass. Prof.Höistad, Bo, Prof.