International Journal of Modern Physics A c © World Scientific Publishing Company Measurement of the η → pi+pi−pi0 decay with WASA-at-COSY detector

One of the objectives of the physics programme of the WASA-at-COSY facility is to study the isospin violating η hadronic decays into pi+pi−pi0 systems driven by the term of QCD Lagrangian which depends on the d and u quark mass difference. These studies can be made in terms of the Dalitz plot parameters describing the density population which is proportional to the square of the amplitude |A(x, y)|2. This contribution describes the current status of the analysis of the η → pi+pi−pi0 decay in the pd →3 Heη and as well in the pp → ppη reaction with WASA-at-COSY