Towards the ωπ transition form factor

One of the major physics motivation of the WASA-at-COSY experiment is to determine transition form factors of light mesons. The ωπ transition form factor is observed through the conversion decay ω → π0γ* → π0 e+e−. The squared four-momentum transferred by virtual photon γ* corresponds to the squared invariant mass distribution of lepton and antilepton pairs. The comparison of the lepton-antilepton mass distribution with the QED prediction, based on the assumption that mesons are point-like particles, gives information about the structure arising at the transition. While these form factors are important properties of hadrons, the information on transition form factors is also required for the interpretation of the g-2 and π0 → e+e− experiments. One of the prominent decay channels, ω → π0γ, is the reference channel in the extraction of the form factor as it is the real photon case. In this paper, the ongoing analysis towards the ωπ transition form factor where the first step is the observation of the ω → π0γ decay will be reported