THE pp -> d pi(+)pi(0) REACTION - A CASE OF Delta Delta EXCITATION WITHOUT ABC-EFFECT
2009 (English)In: International Journal of Modern Physics A, ISSN 0217-751X, E-ISSN 1793-656X, Vol. 24, no 2-3, 561-563 p.Article in journal (Refereed) Published
The ABC effect, a low-mass enhancement in the invariant pp mass, is observed in double-pionic fusion reactions leading to a bound nuclear system in the final state. From previous measurements there have been indications that this phenomenon is resctricted to the sigma channel of the pp system. With exclusive measurements of the pp -> d pi(+)pi(0) reaction at T-p = 1.1 GeV we demonstrate that, indeed, the ABC effect does not occur in the vector-isovector Delta Delta channel (rho channel) despite the fact that the Delta Delta excitation is oberved to be the dominant reaction process. We also show that this reaction is well described by a t-channel Delta Delta excitation with the subsequent decay into the vector-isovector Delta Delta channel given by the rho channel operator.
Place, publisher, year, edition, pages
2009. Vol. 24, no 2-3, 561-563 p.
ABC effect, rho channel, Delta Delta excitation
IdentifiersURN: urn:nbn:se:uu:diva-149123DOI: 10.1142/S0217751X09044073ISI: 000263880300064OAI: oai:DiVA.org:uu-149123DiVA: diva2:404082