4 ΛΛ bond energy from the Nijmegen potentials

The ΛΛ bond energy ∆B ΛΛ in ΛΛ hypernuclei is obtained from a G-matrix calculation which includes the coupling between the ΛΛ, ΞN and ΣΣ channels, as well as the effect of Pauli blocking to all orders. The Nijmegen NSC97e model is used as bare baryon-baryon interaction in the strangeness S = −2 sector. The ΛΛ-ΞN coupling increases substantially the bond energy with respect to the uncoupled ΛΛ case. However, the additional incorporation of the ΣΣ channel, which couples simultaneously to ΛΛ and ΞN states, has a surprisingly drastic effect and reduces the bond energy down to a value closer to that obtained in an uncoupled calculation. We find that a complete treatment of Pauli blocking reduces the repulsive effect on the bond energy to about half of what was claimed before.