The eta decay constant in `resummed' chiral perturbation theory

Abstract

The recently developed 'Resummed' ChPT is illustrated on the case of pseudoscalar meson decay constants. We try to get an estimate of the eta decay constant, which is not well known from experiments, while using several ways including the Generalized ChPT Lagrangian to gather information beyond Standard next-to-leading order. We compare the results to published ChPT predictions, our own Standard ChPT calculations and available phenomenological estimates.