Nuclear forces with Δ excitations up to next-to-next-to-leading order, part I:: Peripheral nucleon-nucleon waves

We study the two-nucleon force at next-to- next-to- leading order in a chiral effective field theory with explicit Delta degrees of freedom. Fixing the appearing low-energy constants from a next-to-leading-order calculation of pion-nucleon threshold parameters, we find an improved convergence of most peripheral nucleon- nucleon phases compared to the theory with pions and nucleons only. In the delta-full theory, the next-to-leading-order corrections are dominant in most partial waves considered.