Exploring the Low-$Z$ Shore of the Island of Inversion at $N = 19$

G. Christian; N. Frank; S. Ash; T. Baumann; D. Bazin; J. Brown; P. A. DeYoung; J. E. Finck; A. Gade; G. F. Grinyer; A. Grovom; J. D. Hinnefeld; E. M. Lunderberg; B. Luther; M. Mosby; S. Mosby; T. Nagi; G. F. Peaslee; W. F. Rogers; J. K. Smith; J. Snyder; A. Spyrou; M. J. Strongman; M. Thoennessen; M. Warren; D. Weisshaar; A. Wersal

doi:10.1103/physrevlett.108.032501

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arXiv · 1201.1267

Exploring the Low-$Z$ Shore of the Island of Inversion at $N = 19$

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Abstract

The technique of invariant mass spectroscopy has been used to measure, for the first time, the ground state energy of neutron-unbound $^{28}\textrm{F},$ determined to be a resonance in the $^{27}\textrm{F} + n$ continuum at $2\underline{2}0 (\underline{5}0)$ keV. States in $^{28}\textrm{F}$ were populated by the reactions of a 62 MeV/u $^{29}\textrm{Ne}$ beam impinging on a 288 $\textrm{mg/cm}^2$ beryllium target. The measured $^{28}\textrm{F}$ ground state energy is in good agreement with USDA/USDB shell model predictions, indicating that $pf$ shell intruder configurations play only a small role in the ground state structure of $^{28}\textrm{F}$ and establishing a low-$Z$ boundary of the island of inversion for N=19 isotones.

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G. Christian, N. Frank, S. Ash, T. Baumann, D. Bazin, J. Brown, P. A. DeYoung, J. E. Finck, A. Gade, G. F. Grinyer, A. Grovom, J. D. Hinnefeld, E. M. Lunderberg, B. Luther, M. Mosby, S. Mosby, T. Nagi, G. F. Peaslee, W. F. Rogers, J. K. Smith, J. Snyder, A. Spyrou, M. J. Strongman, M. Thoennessen, M. Warren, D. Weisshaar, A. Wersal. 2012-01-05. Exploring the Low-$Z$ Shore of the Island of Inversion at $N = 19$. https://doi.org/10.1103/physrevlett.108.032501

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