Description of single-Λ hypernuclei with a relativistic point-coupling model

We extend the relativistic point-coupling model to single-Λ hypernuclei. For this purpose, we add N-Λ effective contact couplings to the model Lagrangian and determine the parameters by fitting to the experimental data for Λ binding energies. Our model well reproduces the data over a wide range of mass region although some of our interactions yield the reverse ordering of the spin-orbit partners from that of nucleons for heavy hypernuclei. The consistency of the interaction with the quark model predictions is also discussed.