A different interpretation of the nuclear shell model

The standard nuclear shell model emerged in the fifties from the study of the properties of the ground state of nuclei such as the discontinuities in binding energies, the pairing energy between two nucleons, the spin of odd nuclei etc., leading to the concept of ''Magic Numbers''. It appeared soon that the ground and low lying excited states can be constructed, in the first approximation, from the Harmonic Oscillator (H.O.) states when a suitable spin-orbit interaction is introduced. As the harmonic oscillator is an independent particle model it has been concluded that each nucleon is moving into a common average field generated by the interaction of one particle with the others. It is an independent particle model (IPM). But the H.O. is a confining potential preventing any nucleon to escape from the nucleus. Therefore another potential, like the Woods-Saxon well, vanishing at infinity has been substituted for the H.O. potential in order to allow nucleons to be separated from nuclei and generate a better charge density. Ultimately the Hartree-Fock method has been used for generating an average field from a potential (e.g. Skyrme), adapted to the method, yielding good binding energies and densities for nuclei. The author's approach starts also from the H.O. Model but leads to another conclusion