The structure of hypernuclei and hyperon mixing in neutron-star matter

We review our recent studies of the structure of Λ hypernuclei within the framework of the Gaussian expansion method for s- and p-shell hypernuclei and the mean-field approach for sd-shell hypernuclei. Specifically, we focus on the structures of (i) the energy splittings of the – and – levels in Be and within the framework of and , three- and four-body cluster models for the hyperon–nucleon (Y–N) spin–orbit force; (ii) the system for coupling; (iii) the weakly bound states or resonant states of neutron-rich Λ hypernuclei such as and He within the framework of and four-body models; and (iv) the tensor correlation effect and super-deformation structure of Λ hypernuclei based on sd-shell nuclei with mass using the deformed Skyrme–Hartree–Fock model and the antisymmetrized molecular dynamics model. As an extreme limit of nuclei including multiple hyperons, we review hyperon effects in neutron-star matter in the high-density region using recent Y–N interactions.