Perturbative $NN$ scattering in chiral effective field theory

Abstract

Within the framework of chiral effective field theory, perturbative calculation for $NN$ scattering is carried out in partial waves with orbital angular momentum $L⩾1$. The primary goal is to identify the lowest angular momenta at which perturbative treatment of chiral forces can apply. Results up to the order where the subleading two-pion exchange appears are shown. It is concluded that perturbation theory applies to all partial waves but ${}^1{S}_0$, ${}^3{S}_1-{}^3{D}_1$, and ${}^3{P}_0$. Where it is applicable, perturbation theory with the delta-less chiral forces produces good agreement with the empirical phase shifts up to $k_{\text{c.m.}}\simeq 300$ MeV.

Comments: Matches published version; suppression of TPEs accounted for at referee's suggestion; main conclusion unchanged, that most P waves and higher waves are perturbative