Assessing the BUQEYE Model for Effective Field Theory Correlated Truncation Errors

The BUQEYE model is a Bayesian model of correlated effective field theory (EFT) truncation errors. It hypothesizes that dimensionless coefficient functions extracted from the order-by-order corrections to observables can be treated as draws from a Gaussian process (GP). Recent work applied to nucleon-nucleon observables combines a variety of graphical and statistical diagnostics to assess when predicted observables have a chiral EFT convergence pattern consistent with the hypothesized GP statistical model. We have demonstrated the BUQEYE model's success in describing truncation errors for Reinert, Krebs, and Epelbaum's 500 MeV semi-local momentum-space potential. The analysis has yielded recommendations for model-specific parametrization choices and generated preliminary estimates for the soft scale and breakdown scale of the theory. However, the analysis has also identified issues with assumed GP stationarity. Work reported here extends to comparisons (a) within regulation schemes (potentials) across regulator scales (cutoffs), (b) across schemes, with implications for scheme choice and "hard" vs. "soft" cutoffs; and (c) using nonstationary GP kernels.