Rigorous constraints on three-nucleon forces in chiral effective field theory from fast and accurate calculations of few-body observables
S. Wesolowski🇺🇸 · I. Svensson🇸🇪 · A. Ekström🇸🇪 · C. Forssén🇸🇪 · R. J. Furnstahl🇺🇸 · J. A. Melendez🇺🇸 · D. R. Phillips🇺🇸
We explore the constraints on the three-nucleon force (3NF) of chiral effective field theory (EFT) that are provided by bound-state observables in the and sectors. Our statistically rigorous analysis incorporates experimental error, computational method uncertainty, and the uncertainty due to truncation of the EFT expansion at next-to-next-to-leading order. A consistent solution for the H binding energy, the He binding energy and radius, and the H -decay rate can only be obtained if EFT truncation errors are included in the analysis. All of these except the -decay rate give essentially degenerate constraints on the 3NF low-energy constants, so it is crucial for estimating these parameters. We use eigenvector continuation for fast and accurate emulation of No-Core Shell Model calculations of the considered few-nucleon observables. This facilitates sampling of the posterior probability distribution, allowing us to also determine the distributions of the hyperparameters that quantify the truncation error. We find a EFT expansion parameter of for these observables.