English

Shell evolution in neutron-rich carbon isotopes: Unexpected enhanced role of neutron-neutron correlation

Nuclear Theory 2012-09-26 v1

Abstract

Full shell-model diagonalization has been performed to study the structure of neutron-rich nuclei around 20^{20}C. We investigate in detail the roles played by the different monopole components of the effective interaction in the evolution of the N=14 shell in C, N and O isotopes. It is found that the relevant neutron-neutron monopole terms, Vd5/2d5/2nnV^{nn}_{d_{5/2}d_{5/2}} and Vs1/2s1/2nnV^{nn}_{s_{1/2}s_{1/2}}, contribute significantly to the reduction of the N=14 shell gap in C and N isotopes in comparison with that in O isotopes. The origin of this unexpectedly large effect, which is comparable with (sometimes even larger than) that caused by the proton-neutron interaction, is related to the enhanced configuration mixing in those nuclei due to many-body correlations. Such a scheme is also supported by the large B(E2) value in the nucleus 20^{20}C which has been measured recently.

Keywords

Cite

@article{arxiv.1209.5583,
  title  = {Shell evolution in neutron-rich carbon isotopes: Unexpected enhanced role of neutron-neutron correlation},
  author = {Cenxi Yuan and Chong Qi and Furong Xu},
  journal= {arXiv preprint arXiv:1209.5583},
  year   = {2012}
}