A-dependence of ΛΛ bond energies in double-Λ hypernuclei

The A-dependence of the bond energy ΔBΛΛ of the ΛΛ hypernuclear ground states is calculated in a three-body Λ + Λ +AZ model and in the Skyrme-Hartree-Fock approach. Various ΛΛ and Λ-nucleus or ΛN potentials are used and the sensitivity of ΔBΛΛ to the interactions is discussed. It is shown that in medium and heavy ΛΛ hypernuclei, ΔBΛΛ is a linear function of rΛ− 3, where rΛ is rms radius of the hyperon orbital. It looks unlikely that it will be possible to extract ΛΛ interaction from the double-Λ hypernuclear energies only, the additional information about the Λ- core interaction, in particular, on rΛ is needed.