Studies of the η→π+π−e+e− decay channel

Predictions for invariant mass distributions of electron and pion pairs from the η→π+π−e+e− decay have been recently given in a chiral unitary approach. They have to wait for experimental verification since up to now only few events were observed. The WASA‐at‐COSY collaboration has started investigations of this channel with high statistics. The analysis tools could also be used in future for of the analogous decay of the η′ meson.