English

Collapse of the N=28 shell closure in $^{42}$Si

Nuclear Experiment 2008-11-26 v1

Abstract

The energies of the excited states in very neutron-rich 42^{42}Si and 41,43^{41,43}P have been measured using in-beam γ\gamma-ray spectroscopy from the fragmentation of secondary beams of 42,44^{42,44}S at 39 A.MeV. The low 2+^+ energy of 42^{42}Si, 770(19) keV, together with the level schemes of 41,43^{41,43}P provide evidence for the disappearance of the Z=14 and N=28 spherical shell closures, which is ascribed mainly to the action of proton-neutron tensor forces. New shell model calculations indicate that 42^{42}Si is best described as a well deformed oblate rotor.

Keywords

Cite

@article{arxiv.0705.4526,
  title  = {Collapse of the N=28 shell closure in $^{42}$Si},
  author = {B. Bastin and S. Grévy and D. Sohler and O. Sorlin and Zs. Dombrádi and N. L. Achouri and J. C. Angélique and F. Azaiez and D. Baiborodin and R. Borcea and C. Bourgeois and A. Buta and A. Bürger and R. Chapman and J. C. Dalouzy and Z. Dlouhy and A. Drouard and Z. Elekes and S. Franchoo and S. Iacob and B. Laurent and M. Lazar and X. Liang and E. Liénard and J. Mrazek and L. Nalpas and F. Negoita and N. A. Orr and Y. Penionzhkevich and Zs. Podolyák and F. Pougheon and P. Roussel-Chomaz and M. G. Saint-Laurent and M. Stanoiu and I. Stefan and F. Nowacki and A. Poves},
  journal= {arXiv preprint arXiv:0705.4526},
  year   = {2008}
}

Comments

4 pages, 3 figures, accepted for publication in Phys. Rev. lett