L-L Interaction and ll6He

A one-boson exchange (OBE) potential model, based on the Nijmegen model D potential, for the ${}^{1}{S}_{0},$ $S=\ensuremath{-}2$ interaction is analyzed with emphasis on the role of coupling between the \ensuremath{\Lambda}\ensuremath{\Lambda}, $N\ensuremath{\Xi},$ and \ensuremath{\Sigma}\ensuremath{\Sigma} channels. Singlet scalar exchange, an approximation to two-pion exchange, is significant in all channels; surprisingly, the one-pion exchange component is almost negligible. The size of the channel coupling as a function of the overall strength of the OBE model potential is examined. Implications of the analysis for the binding energy of ${}_{\ensuremath{\Lambda}\ensuremath{\Lambda}}^{6}\mathrm{He}$ are considered; the new experimental datum may suggest a consistency between the extracted \ensuremath{\Lambda}\ensuremath{\Lambda} matrix element and the relation implied by SU(3) among OBE baryon-baryon interactions.