Chiral Dynamics Predictions for $\eta'\to\eta\pi\pi$

TL;DR

This paper compares two chiral invariant theoretical approaches, Large-Nc ChPT and RChT, to predict the decay properties of eta' to eta pi pi, highlighting their agreement and discrepancies with experimental data.

Contribution

It provides a detailed analysis of eta' decay using two advanced chiral theories and assesses their predictions against experimental results.

Findings

RChT shows better agreement with experimental decay width.

ChPT predictions at next-to-leading order need refinement for accuracy.

Future experiments will help distinguish between the theoretical frameworks.

Abstract

We study the decay $\eta'\to\eta\pi\pi$ 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, J\"ulich and Mainz will decide among the different frameworks.