Abstract:
The Dalitz decays η → e+e−γ andω → π0e+e− have been measured in the γp → ηp and γp → ωp reactions,
respectively, with the A2 tagged-photon facility at the Mainz Microtron. The value obtained for the slope parameter
of the electromagnetic transition form factor of η, −2
η = (1.97 ± 0.11tot) GeV−2
, is in good agreement with
previous measurements of the η → e+e−γ and η → μ+μ−γ decays. The uncertainty obtained in the value of −2
η
is lower than in previous results based on the η → e+e−γ decay. The value obtained for the ω slope parameter,
−2
ωπ0 = (1.99 ± 0.21tot) GeV−2
, is somewhat lower than previous measurements based on ω → π0μ+μ−, but
the results for the ω transition form factor are in better agreement with theoretical calculations, compared to
earlier experiments
