Identification of the crossing point at N=21 between normal and intruder configurations

R. Licǎ, F. Rotaru, M. J G Borge, S. Grévy, F. Negoiţǎ, A. Poves, O. Sorlin, Andrei Andreyev, R. Borcea, C. Costache, H. De Witte, L. M. Fraile, P. T. Greenlees, M. Huyse, A. Ionescu, S. Kisyov, J. Konki, I. Lazarus, M. Madurga, N. MǎrgineanR. Mǎrginean, C. Mihai, R. E. Mihai, A. Negret, R. D. Page, J. Pakarinen, S. Pascu, V. Pucknell, P. Rahkila, E. Rapisarda, A. Şerban, C. O. Sotty, L. Stan, M. Stǎnoiu, O. Tengblad, A. Turturicǎ, P. Van Duppen, R. Wadsworth, N. Warr

Research output: Contribution to journalArticlepeer-review


The β− decay of 34Mg was used to study the 34Al
nucleus through g-ray spectroscopy at the Isotope Separator On-Line facility of CERN. Previous studies identified two β-decaying states in 34Al having spin-parity assignments Jπ=4−dominated by the normal configurationπ
(d5/2)−1⊗ν(f7/2) and Jπ=1+ by the intruder configuration π(d5/2)−1⊗ν(d3/2)−1(f7/2)2 . Their unknown ordering and relative energy have been the subject of debate for the placement of 34Al inside or outside the N=20 “island of inversion.” We report here that the 1+ intruder lies only 46.6 keV above the 4− ground state. In addition, a new half-life of T1/2=44.9(4)ms, that is twice as long as the previously measured 20(10) ms, has been determined for 34Mg. Large-scale shell-model calculations with the recently developed sdpf-u-mix interaction are compared with the new data and used to interpret the mechanisms at play at the very border of the N=20 island of inversion.
Original languageEnglish
Article number021301(R)
Pages (from-to)21301
Number of pages1
JournalPhysical Review C
Issue number2
Publication statusPublished - 9 Feb 2017

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