Determination of the m_u and m_d quark masses from eta\rightarrow 3pi decay

Abstract

Chiral analysis of η → 3π decay can provide us with information on isospin breaking effects, which is still needed for precise determination of light quark masses using lattice techniques or QCD sum rules. However, this process is affected by large chiral corrections and there are observed discrepancies between the values of Dalitz plot parameters stemming from the standard ChPT computation of its amplitude and those experimentally measured. By using an analytic dispersive representation we have attempted to obtain the information on the masses by taking this discrepancy into account independently of its exact origin. We have performed two distinct analyses of KLOE experimental data on the charged η → π + π − π 0 decay using two general sets of assumptions on the physical amplitude and found that both of the sets are compatible with the data and both of them lead to compatible values for R = PoS(EPS-HEP2011)411Determination of the m u and m d quark masses from η → 3π decay Martin ZDRÁHAL