The Isospin Independent Spin-Orbit Force in the Extended Skyrme Model

By using the product ansatz as an approximation for the two-baryon system we investigate the isoscalar nucleon-nucleon spin-orbit potential in an extended Skyrme model including both fourth- and sixth-order terms. As it is the case for the Skyrme model, we still obtain the wrong sign for this interaction. Nevertheless, concerning the order of magnitude, the extended Skyrme model provides a better agreement with phenomenological potentials, as compared to the standard one.