%0 Journal Article
%T Evolution of shell structure in neutron-rich calcium isotopes
%A G. Hagen
%A M. Hjorth-Jensen
%A G. R. Jansen
%A R. Machleidt
%A T. Papenbrock
%J Physics
%D 2012
%I arXiv
%R 10.1103/PhysRevLett.109.032502
%X We employ interactions from chiral effective field theory and compute the binding energies and low-lying excitations of calcium isotopes with the coupled-cluster method. Effects of three-nucleon forces are included phenomenologically as in-medium two-nucleon interactions, and the coupling to the particle continuum is taken into account using a Berggren basis. The computed ground-state energies and the low-lying 2+ states for the isotopes 42,48,50,52Ca are in good agreement with data, and we predict the excitation energy of the first 2+ state in 54Ca at 1.9 MeV, displaying only a weak sub-shell closure. In the odd-mass nuclei 53,55,61Ca we find that the positive parity states deviate strongly from the naive shell model.
%U http://arxiv.org/abs/1204.3612v2