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arXiv · 2006.02712

Examining the $N$ = 28 shell closure through high-precision mass measurements of $^{46-48}$Ar

Maxime Mougeot·Dinko Atanasov·Carlo Barbieri·Klaus Blaum·Martin Breitenfeld·Antoine de Roubin·Thomas Duguet·Sebastian George·Frank Herfurth·Alexander Herlert·Jason D. Holt·Jonas Karthein·David Lunney·Vladimir Manea·Petr Navràtil·Dennis Neidherr·Marco Rosenbusch·Lutz Schweikhard·Achim Schwenk·Vittorio Somà·Andree Welker·Frank Wienholtz·Robert N. Wolf·Kai Zuber
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Abstract

The strength of the $N$ = 28 magic number in neutron-rich argon isotopes is examined through high-precision mass measurements of $^{46-48}$Ar, performed with the ISOLTRAP mass spectrometer at ISOLDE/CERN. The new mass values are up to 90 times more precise than previous measurements. While they suggest the persistence of the $N$ = 28 shell closure for argon, we show that this conclusion has to be nuanced in light of the wealth of spectroscopic data and theoretical investigations performed with the \emph{SDPF-U} phenomenological shell model interaction. Our results are also compared with \emph{ab initio} calculations using the Valence Space In-Medium Similarity Renormalization Group and the Self-Consistent Green's Function approaches. Both calculations provide a very good account of mass systematics at and around $Z$ = 18 and, generally, a consistent description of the physics in this region. This combined analysis indicates that $^{46}$Ar is the transition between the closed-shell $^{48}$Ca and collective $^{44}$S.

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Maxime Mougeot, Dinko Atanasov, Carlo Barbieri, Klaus Blaum, Martin Breitenfeld, Antoine de Roubin, Thomas Duguet, Sebastian George, Frank Herfurth, Alexander Herlert, Jason D. Holt, Jonas Karthein, David Lunney, Vladimir Manea, Petr Navràtil, Dennis Neidherr, Marco Rosenbusch, Lutz Schweikhard, Achim Schwenk, Vittorio Somà, Andree Welker, Frank Wienholtz, Robert N. Wolf, Kai Zuber. 2020-06-04. Examining the $N$ = 28 shell closure through high-precision mass measurements of $^{46-48}$Ar. https://doi.org/10.1103/physrevc.102.014301

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