Hyperon–nucleon interaction in chiral effective field theory at next-to-next-to-leading order

Abstract

A hyperon–nucleon potential for the strangeness S=-1 sector (varLambda N, varSigma N) up to third order in the chiral expansion is presented. SU(3) flavor symmetry is imposed for constructing the interaction, however, the explicit SU(3) symmetry breaking by the physical masses of the pseudoscalar mesons and in the leading-order contact terms is taken into account. A novel regularization scheme is employed which has already been successfully used in studies of the nucleon–nucleon interaction within chiral effective field theory up to high orders. An excellent description of the low-energy varLambda p, varSigma ^- p and varSigma ^+ p scattering data is achieved. New data from J-PARC on angular distributions for the varSigma N channels are analyzed. Results for the hypertriton and A=4 hyper-nuclear separation energies are presented. An uncertainty estimate for the chiral expansion is performed for selected hyperon–nucleon observables.