Description of single-Lambda hypernuclei with relativistic point coupling model

We extend the relativistic point coupling model to single-$Lambda$ hypernuclei. For this purpose, we add $N$-$Lambda$ effective contact couplings to the model Lagrangian, and determine the parameters by fitting to the experimental data for $Lambda$ 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.