Light quark mass ratio from the Dalitz plot of η→π+π-π0 decay

High statistics Dalitz-plot distribution of η→π+π-π0 decay obtained recently by KLOE collaboration is fitted to the results of corresponding theoretical calculations in Chiral Perturbation Theory (ChPT) with unitarity corrections taken into account. The quark mass ratio Q=√([ms2-(md+mu)2/4]/(md2-mu2)) can be obtained from this analysis. We get Q=22.8±0.4 which differs from the value QDT=24.2 that follows from Dashen's theorem and agrees with recently calculated electromagnetic kaon mass difference