Chiral dynamics predictions for $\eta\prime\rightarrow \eta \pi \pi$

We study the decay η ′ → ηππ in two different chiral invariant approaches: Large-N c Chiral Perturbation Theory (ChPT) and Large-N c Resonance Chiral Theory (RChT).We analyze the Dalitz plot and the invariant mass spectra.We also compare the relevance of the isoscalar and isovector channels in these approaches.While the predictions of Large-N c ChPT at next-to-leading order slightly disagree with the measured decay width (showing the need for final state interactions and higher order local contributions), a reasonable agreement is obtained for the case of RChT.Forthcoming experimental analyses at Bonn, Frascati, Jülich and Mainz will decide among the different frameworks.