Results on the analysis of the η→3π circle decay with WASA-at-COSY

During the first production run of the WASA experiment at the COSY storage ring the η→3π circle decay has been measured in proton-proton interactions at an excess energy of Q=56 MeV. The goal of the experiment is the measurement of the 3π circle Dalitz plot density distribution which allows a precise test of chiral perturbation theory calculations. The decay system was tagged by the WASA forward detector using the recoil protons. The η decay was reconstructed in the central detector by the subsequent π circle →γγ decays. A kinematic fit with constraints was applied in order to optimally use the measured information. The constraints used in the fit are the masses of the subsequently decayed pions, as well as the mass of final state particles of in the eta-meson decay system. We report on the final results of the analysis.