The Dalitz decay η→e+e-γ has been measured in the γp→ηp reaction with the Crystal Ball and TAPS multiphoton spectrometers, together with the photon-tagging facility at the Mainz Microtron MAMI. The experimental statistic used in this work is one order of magnitude greater than in any previous measurement of η→e+e-γ. The value obtained for the slope parameter Λ-2 of the η transition form factor, Λ-2=(1.95±0.15stat±0.10syst) GeV-2, is in good agreement with recent measurements conducted in η→e+e-γ and η→μ+μ-γ decays, as well as with recent form-factor calculations. The uncertainty obtained in the value of Λ-2 is lower compared to results from previous measurements of the η→e+e-γ decay.
ASJC Scopus subject areas
- Nuclear and High Energy Physics