Improved effective interaction for the hyperspherical formalism

An improvement of the recently developed effective interaction method for the hyperspherical formalism is presented. The method is extended to include contributions of three-body effective forces and of the nonadiabatic kinetic energy term. The role of these two additional contributions is tested on the binding energy of ⁴He and ⁶Li using semirealistic and more realistic NN potential models. The rate of convergence is improved considerably, opening up the possibility to use the method with realistic two- and three-body potentials for the α-particle and for few-body nuclei with more than four nucleons.