Chiral dynamics predictions for η → ηππ

The hadronic decays η → ηππ are studied in the frameworks of large-NC Chiral Perturbation Theory, at lowest and next-to-leading orders, and Resonance Chiral Theory in the leading 1/NC approximation. Higher order effects such as ππ final state interactions are taken into account through a detailed unitarization procedure. The inclusion of finite-width effects in the case of RChT is also discussed. The Dalitz plot distribution and the differential branching ratio are computed in both approaches. The predicted Dalitz plot parameters obtained from the different treatments are compared with the most recent measured values. We find that the η → ηππ branching ratios are easily understood, while the Dalitz plot parameters require the inclusion of ππ loops in order to achieve a reasonable agreement. Our final predictions agree with the experimental measurements. We hope our results to be of relevance for present and future experimental analyses of these decays. © SISSA 2011.