Implications of an increased Λ-separation energy of the hypertriton

Abstract

Stimulated by recent indications that the binding energy of the hypertriton could be significantly larger than so far assumed, requirements of a more strongly bound HΛ3 state for the hyperon-nucleon interaction and consequences for the binding energies of A=4,5 and 7 hypernuclei are investigated. As basis, a YN potential derived at next-to-leading order in chiral effective field theory is employed. Faddeev and Yakubovsky equations are solved to obtain the corresponding 3- and 4-body binding energies, respectively, and the Jacobi no-core shell model is used for Λ5He and Λ7Li. It is found that the spin-singlet Λp interaction would have to be much more attractive which can be, however, accommodated within the bounds set by the available Λp scattering data. The binding energies of the HeΛ4 hypernucleus are predicted to be closer to the empirical values than for YN interactions that produce a more weakly bound HΛ3. The quality of the description of the separation energy and excitation spectrum for Λ7Li remains essentially unchanged.