In view of the recent high-statistic KLOE data for the η→π+π−π0 decay, a new determination of the quark mass double ratio has been done. Our approach relies on a dispersive model that takes into account rescattering effects between three pions via subenergy unitarity. The latter is essential to reproduce the Dalitz plot distribution. A simultaneous description of the KLOE and WASA-at-COSY data is achieved in terms of just two real parameters. From a global fit, we determine Q=21.6±1.1. The predicted slope parameter for the neutral channel α=−0.025±0.004 is in reasonable agreement with the PDG average value.
@article{arxiv.1608.01447,
title = {Three-body final state interaction in $\eta \to 3 \pi$ updated},
author = {P. Guo and I. V. Danilkin and C. Fernández-Ramírez and V. Mathieu and A. P. Szczepaniak},
journal= {arXiv preprint arXiv:1608.01447},
year = {2017}
}