Configuration mixing description of the nucleus ${}^{44}$S

We study the structure of the neutron rich ${}^{44}$S isotope with modern configuration mixing methods based on the Gogny interaction including beyond-mean-field effects. Restoration of particle number and rotational symmetries are taken into account as well as shape mixing in the whole triaxial $({\beta }_2,\gamma )$ plane. We obtain a qualitative agreement between the calculated spectrum and the experimental data reported recently. Very extended collective wave functions in the $({\beta }_2,\gamma )$ plane are found for the lowest states, corresponding to very flat potentials, indicating strong configuration mixing and supporting the weakening of the N=28 magic number.