Exotic Nucleus Helium-9 and its Excited States
1987; American Physical Society; Volume: 58; Issue: 19 Linguagem: Inglês
10.1103/physrevlett.58.1930
ISSN1092-0145
AutoresKamal K. Seth, M. Artuso, D. Barlow, S. Iversen, M. Kaletka, H. Nann, B. Parker, R. Soundranayagam,
Tópico(s)Advanced Chemical Physics Studies
ResumoThe ground state and several excited states of $^{9}\mathrm{He}$, the most neutron-rich nucleus to date, have been identified by means of the reaction $^{9}\mathrm{Be}({\ensuremath{\pi}}^{\ensuremath{-}}, {\ensuremath{\pi}}^{+})^{9}\mathrm{He}$. The mass excess of the ground state has been measured and it is found that the nucleus is unbound against single-neutron decay by 1.13\ifmmode\pm\else\textpm\fi{}0.10 MeV only. It is found that the excited-state spectrum of this nucleus, which is very far from the valley of stability, is in good agreement with the predictions of "no-core" shell-model calculations whose parameters were optimized for the stable nuclei in the valley.
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