1210.3156 (Małgorzata Hodana et al.)

Study of the η-->e+e-γ Decay using WASA-at-COSY Detector
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Małgorzata Hodana, Paweł Moskal, for the WASA-at-COSY Collaboration

At the turn of October and November 2008, the WASA-at-COSY collaboration performed an experiment to collect data on the \eta meson decays in pd-->3He\eta{} reactions. This report presents results of a study of the \eta-->e+e\gamma{} conversion decay. The desired feature of this decay is that the final state e+e- pairs come from the conversion of a virtual \gamma{} quantum and, therefore, they constitute a rich source of knowledge about the electromagnetic structure of decaying meson. This is a very important characteristic when it comes to study of a short-lived neutral particle like the \eta{} meson, because the classical methods of particle scattering are not applicable here. The analysis performed on one third of the p-d data sample collected using the WASA-at-COSY detector, lead to the extraction of the \eta{} transition form factor as a function of the e+e- mass and to the calculation of the slope parameter, related to the charge radius of the \eta{} meson.

View original: http://arxiv.org/abs/1210.3156