Few-nucleon forces from chiral Lagrangians

Abstract

Few-nucleon forces are considered from the point of view of effective chiral Lagrangians. It is argued that such forces naturally arise at the same order in chiral perturbation theory as some important features of the two-nucleon force. In particular, the leading few-nucleon forces cancel against the leading recoil correction in the iteration of the two-body potential. The remaining three-body potential is presented in momentum and coordinate spaces. It is dominated by contributions of the delta isobar of (i) two-pion range, which are not new, and (ii) shorter range, which involve an undetermined parameter.