ΛN-interaction and spin-orbit coupling in hypernuclei

The spin-orbit interaction for a Λ in a hypernucleus is discussed within the framework of a relativistic Hartree model using effective scalar and vector boson exchange interactions as input. Meson exchange models of such ΛN-interactions indicate that the relevant parts of them should be much weaker than the corresponding pieces of the nucleon-nucleon force. As a consequence, the central Hartree potential for a Λ is considerably less attractive than that for a nucleon, and the spin-orbit splitting in the p-shell of ¹⁶O is reduced to about 1 MeV.