We apply Bayesian inference to the order-by-order chiral perturbation theory ( χ PT) expansions for the axial-vector coupling constant g A and the nucleon mass m N , and thereby infer the scales at which χ PT breaks down for these two observables. Using a pointwise Bayesian analysis, we find that the inferred breakdown scales are notably different for the two observables. For the chiral expansion of g A , we obtain 251 − 50 + 20 MeV and 211 − 30 + 20 MeV using two distinct sets of low-energy constants, while for the chiral expansion of m N we infer a significantly larger breakdown scale of 491 − 90 + 60 MeV.
Ekström et al. (Sun,) studied this question.