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, which indicate wide configuration mixing and support the weakening of the $N=28$ magic number.

• Received 6 September 2011

DOI:https://doi.org/10.1103/PhysRevC.84.051307