Abstract
The ABC effect—a puzzling low‐mass enhancement in the ππ invariant mass spectrum—is known from inclusive measurements of two‐pion production in nuclear fusion reactions. Exclusive measurements conducted at CELSIUS‐WASA for the fusion reactions leading to d and 3He in the final state reveal the ABC effect to be of scalar‐isoscalar nature and to be associated with the formation of a resonance in the pn↔ΔΔ systems in the intermediate state. The differential distributions for the π0π0 channels can be well described, if a quasi‐bound state within the ΔΔ system is assumed, which gives rise to a resonance structure in the total cross section. This ansatz is capable of describing all differential cross sections including the results of previous inclusive measurements on 4He as well as the energy dependence of the total cross sections.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
