Spectroscopy of Na28: Shell evolution toward the drip line

A. Lepailleur et al.
Phys. Rev. C 92, 054309 – Published 16 November 2015

Abstract

Excited states have been studied in Na28 using the β-decay of implanted Ne28 ions at the Grand Accélérateur National d'Ions Lourds/LISE as well as the in-beam γ-ray spectroscopy at the National Superconducting Cyclotron Laboratory/S800 facility. New states of positive (Jπ=3+,4+) and negative (Jπ=15) parity are proposed. The former arise from the coupling between 0d5/2 protons and 0d3/2 neutrons, while the latter are attributable to couplings of 0d5/2 protons with 1p3/2 or 0f7/2 neutrons. While the relative energies between the Jπ=1+4+ states are well reproduced with the USDA interaction in the N=17 isotones, a progressive shift in the ground-state binding energy (by about 500 keV) is observed between F26 and Al30. This points to a possible change in the proton-neutron 0d5/20d3/2 effective interaction when moving from stability to the drip line. The presence of Jπ=14 negative-parity states around 1.5 MeV as well as of a candidate for a Jπ=5 state around 2.5 MeV give further support to the collapse of the N=20 gap and to the inversion between the neutron 0f7/2 and 1p3/2 levels below Z=12. These features are discussed in the framework of shell-model and energy-density-functional calculations, leading to predicted negative-parity states in the low-energy spectra of the F26 and O25 nuclei.

  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
5 More
  • Received 26 March 2015
  • Revised 15 May 2015

DOI:https://doi.org/10.1103/PhysRevC.92.054309

©2015 American Physical Society

Physics Subject Headings (PhySH)

Nuclear Physics

Authors & Affiliations

Click to Expand

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 92, Iss. 5 — November 2015

Reuse & Permissions
Access Options
CHORUS

Article Available via CHORUS

Download Accepted Manuscript
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review C

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×