Quantifying the breakdown scale of pionless effective field theory

Abstract

We use Bayesian statistics to infer the breakdown scale of pionless effective field theory in its standard power counting and with renormalization of observables carried out using the power-divergence subtraction scheme and cutoff regularization. We condition our inference on predictions of the total neutron-proton scattering cross section up next-to-next-to leading order. We quantify a median breakdown scale of approximately 1.4$m_\pi$. The 68% degree of belief interval is $[0.96,1.69]m_\pi$. This result confirms the canonical expectation that the pion mass is a relevant scale in low-energy nuclear physics.