Exploring Bayesian parameter estimation for chiral effective field theory using nucleon-nucleon phase shifts

Understand

We recently developed a Bayesian framework for parameter estimation in general effective field theories.

• Here we present selected results from using that framework to estimate parameters with a nucleon-nucleon (NN) potential derived using chiral effective field theory ($\chi$EFT): the semi-local NN potential of Epelbaum, Krebs, and Mei{\ss}ner (EKM).
• There are many NN scattering data, up to high energies, and with rather small errors, so imposing a penalty for unnatural low-energy constants (LECs) usually has a small effect on the fits.
• In contrast, we have found that including an estimate of higher orders in $\chi$EFT plays an important role in robust parameter estimation.We present two case studies where our Bayesian machinery illuminates physics issues.