A DENSITY-DEPENDENT RELATIVISTIC HARTREE APPROACH FOR HYPERNUCLEI

Lambda, Sigma, and Xi (multi-)hypernuclei are investigated within a de nsity-dependent relativistic Hartree approach. To this end, the covari ant field theory recently developed by Lenske and Fuchs is extended to hypernuclear systems, leading to rearrangement self-energies in the b aryonic field equations. Self-consistent solutions, including omega-hy peron tensor couplings, are obtained in the Hartree limit with the sig ma- and omega-nucleon couplings adjusted to Dirac-Brueckner-Hartree-Fo ck results for infinite nuclear matter, utilizing a local density appr oximation. With the meson-nucleon couplings compatible with realistic nucleon-nucleon potentials, the description remains free of adjustable parameters on the nucleonic side, while meson-hyperon couplings are f ixed by SU(6) symmetry or fitted to available experimental data. In ad dition, results for A hypernuclei are presented within a purely phenom enological relativistic mean-field model including sigma and omega sel f-interactions. Special attention is devoted to the impact of the rho- meson field in Sigma and Xi hypernuclei. Finally, the 'hyperon-halo' o f multi-hypernuclei and the way it is affected by rearrangement effect s is studied.