Convergence properties of $\eta\to 3\pi$ decays in chiral perturbation theory

Understand

Theoretical efforts to describe and explain the $\eta\to 3\pi$ decays reach far back in time.

• Even today, the convergence of the decay widths and some of the Dalitz plot parameters seems problematic in low energy QCD.
• In the framework of resummed CHPT, we explore the question of compatibility of experimental data with a reasonable convergence of a carefully defined chiral series, where NNLO remainders are assumed to be small.
• By treating the uncertainties in the higher orders statistically, we numerically generate a large set of theoretical predictions, which are then confronted with experimental information.