Münster 2017 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 27: Poster
HK 27.13: Poster
Tuesday, March 28, 2017, 16:45–18:45, F Foyer
Search for C-violation in η → π0 e+ e− with WASA-at-COSY* — •Kay Demmich, Florian Bergmann, Nils Hüsken, and Alfons Khoukaz for the WASA-at-COSY collaboration — Institut für Kernphysik, Westfälische Wilhelms-Universität Münster, Germany
The electromagnetic decay η → π0 e+ e− via a virtual photon violates the C-parity and is therefore forbidden within the standard model. Higher order processes are C-convserving but highly suppressed. Hence, this η-decay is a perfect probe to test the C-parity conservation to search for physics beyond the standard model, e.g., for dark bosons. The WASA-at-COSY setup was utilized to collect a huge pp→ ppη data set of ≈5 × 108 η-mesons dedicated for studies on rare and forbidden η-decays. Based on this data set the relative branching ratio can be determined with a significantly higher sensitivity than the current upper limit of 4× 10−5 as quoted by the PDG. Preliminary results of the analysis will be presented and discussed. In a further contribution by the WASA-at-COSY collaboration recent results of the corresponding analysis based on the reaction pd → 3Heη will be presented. 1em *Supported by FFE program of the Forschungszentrum Jülich.