Observation and spectroscopy of proton-unbound nucleus ${}^{21}$Al

Abstract

We report on the observation of previously-unknown isotope ${}^{21}$Al, the first unbound aluminum isotope located beyond the proton dripline. The ${}^{21}$Al nucleus decays by one-proton (1p) emission, and its in-flight decays were detected by tracking trajectories of all decay products with micro-strip silicon detectors. The 1p-emission processes were studied by analyses of the measured angular correlations of decay products ${}^{20}$Mg+p. The 1p-decay energies of ground and low-lying excited states of ${}^{21}$Al, its mass excess and proton separation energy value $S_p$=$-1.1(1)$ MeV were determined.

6 pages, 7 figures

References in corpus (4)

• Three-body forces and proton-rich nuclei
• Beyond the proton drip line: Bayesian analysis of proton-emitting nuclei
• Two-proton emission and related phenomena
• Description of proton-rich nuclei in the $A\sim 20$ region with the Gamow shell model

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• Gamow shell model calculations for the Thomas-Ehrman shift in new isotopes 21Al
• Gamow shell model predictions for six-proton unbound nucleus ${}^{20}$Si
• Gamow shell model study of the 17Ne(p, p) reaction and of isospin symmetry breaking in 18Na