Configuration mixing of mean-field wave-functions projected on angular momentum and particle number; application to Mg-24

We present in this talk the general framework of a method which permits to restore the, rotational and particle number symmetries of wave functions ob tained in Skyrme HF+BCS calculations. This restoration is nothing but a pro jection of mean-field intrinsic wave functions onto good particle number an d good angular momentum. The method allows also to mix projected wave funct ions. Such a configuration mixing is discussed for sets of HF+BCS intrinsic states generated in constrained calculations with suitable collective vari ables. This procedure gives collective states which are eigenstates of the particle number and the angular momentum operators and between which transi tion probabilities axe calculated. A test application to Mg-24 is presented with mean-field wave functions generated by axial quadrupole constraints. Theoretical spectra and transition probabilities are compared to the experi ment. Some preliminary results for Mg-32 and O-16 are also reported.