Evolution of shell structure in neutron-rich calcium isotopes
Abstract
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.
Cite
@article{arxiv.1204.3612,
title = {Evolution of shell structure in neutron-rich calcium isotopes},
author = {G. Hagen and M. Hjorth-Jensen and G. R. Jansen and R. Machleidt and T. Papenbrock},
journal= {arXiv preprint arXiv:1204.3612},
year = {2012}
}
Comments
5 pages, 4 figures; small correction of effective 3NF and slight change of the corresponding parameters; updated figures and tables; main results and conclusions unchanged