A microscopic model beyond mean-field: from giant resonance properties to the fit of new effective interactions

Self-consistent mean-field models are able to reproduce well the overall properties of nuclei for a wide range of masses. Nevertheless, they are intrinsically unsuitable for the description of some important observables like the single-particle strength distribution or, in connection with collective states, their damping width and their gamma decay to the ground state or to low lying states. For this reason, a completely microscopic approach beyond mean- field has been implemented recently, based on the Skyrme functional. When beyond mean-field theories are handled, the mean-field-fitted effective interaction should be refitted at the desired level of approximation. If zero-range interactions are used, divergences arise. We present some steps towards the refitting of Skyrme interactions, for its application in finite nuclei.