Hyperon–nucleon interaction within chiral effective field theory revisited

Abstract

AbstractThe $$\varLambda N$$ΛN and $$\varSigma N$$ΣN interactions are considered at next-to-leading order in SU(3) chiral effective field theory. Different options for the low-energy constants that determine the strength of the contact interactions are explored. Two variants are analysed in detail which yield equivalent results for $$\varLambda N$$ΛN and $$\varSigma N$$ΣN scattering observables but differ in the strength of the $$\varLambda N \rightarrow \varSigma N$$ΛN→ΣN transition potential. The influence of this difference on predictions for light hypernuclei and on the properties of the $$\varLambda $$Λ and $$\varSigma $$Σ hyperons in nuclear matter is investigated and discussed. The effect of the variation in the potential strength of the $$\varLambda N$$ΛN-$$\varSigma N$$ΣN coupling (also called $$\varLambda -\varSigma $$Λ-Σ conversion) is found to be moderate for the considered $$^3_\varLambda {{\mathrm{H}}}$$Λ3H and $$^4_\varLambda \mathrm{He}$$Λ4He hypernuclei but sizable in case of the matter properties. Further, the size of three-body forces and their relation to different approaches to hypernuclear interactions is discussed.