The density dependent relativistic hadron field (DDRH) theory, previously introduced and applied to isospin nuclei, is extended to hypernuclei by including the octet hyperons. Infinite matter Dirac-Brueckner theory for octet baryons and the derivation of in-medium DDRH baryon-meson vertices is discussed. From the properties of Dirac-Brueckner interactions it is found that hyperon and nucleon self-energies and vertices are related by the ratios of free space coupling constants. This leads to simple scaling laws for the in-medium hyperon and nucleon vertices. The model is applied in relativistic DDRH mean-field calculations to single Λ nuclei. Free space $N\Lambda$ T-matrix results are used for the scalar vertex. As the only free parameter the hyperon vector vertex scaling factor is adjusted to a selected set of hypernuclear data. Spectroscopic data of single Λ hypernuclei over the full mass range are well described. A reduction of the Λ spin-orbit splitting is found to be related closely to the medium dependence of scalar and vector interactions.

• Received 4 November 1999

DOI:https://doi.org/10.1103/PhysRevC.61.064309