TITLE

# LOW-MASS Ï€Ï€ ENHANCEMENT IN BARYONIC Ï€Ï€ PRODUCTION:: ABC EFFECT REVISED BY EXCLUSIVE MEASUREMENTS

AUTHOR(S)
Bashkanov, M.; Khakimova, O.; Skorodko, T.; Bargholtz, C.; Bogoslowsky, D.; Calén, H.; Cappellaro, F.; Clement, H.; Ekström, C.; Fransson, K.; Geren, L.; Gustafsson, L.; Höistad, B.; Ivanov, G.; Jacewicz, M.; Jiganov, E.; Johansson, T.; Kaskulov, M. M.; Keleta, S.; Koch, I.
PUB. DATE
January 2007
SOURCE
International Journal of Modern Physics A: Particles & Fields; G;1/30/2007, Vol. 22 Issue 2/3, p625
SOURCE TYPE
DOC. TYPE
Article
ABSTRACT
The ABC effect - a puzzling threshold enhancement in the Ï€Ï€ invariant mass spectrum of double-pionic fusion to nuclear bound states - has been investigated since 40 years by inclusive measurements without providing a conclusive interpretation. First exclusive measurements to this topic have now been carried out at CELSIUS-WASA. They confirm a huge Ï€Ï€ threshold enhancement, prove it to be of scalar-isoscalar nature, i.e., a Ïƒ-channel phenomenon and reveal the theoretically predicted high-mass enhancement in inclusive spectra to be of Ï€Ï€Ï€ rather than of Ï€Ï€ nature - falsifying thus corresponding model predictions for the ABC effect. From the kinematically complete data samples we infer that the interaction between the two Î” particles created in this process is of crucial importance.
ACCESSION #
24098902

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