Direct Evidence for the Breakdown of theN=8Shell Closure inB12e
| Autor: | P. G. Hansen, M. Steiner, B. M. Sherrill, Andreas Wagner, J. A. Tostevin, Boris Pritychenko, B. A. Brown, K. L. Miller, Y. Blumenfeld, P. A. Lofy, D. W. Anthony, E. J. Spears, T. Glasmacher, V. Maddalena, John Yurkon, R. W. Ibbotson, A. Navin, Thomas Aumann, D. Bazin, Thomas Baumann, Takashi Nakamura |
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| Rok vydání: | 2000 |
| Předmět: | |
| Zdroj: | Physical Review Letters. 85:266-269 |
| ISSN: | 1079-7114 0031-9007 |
| DOI: | 10.1103/physrevlett.85.266 |
| Popis: | Partial cross sections and corresponding momentum distributions have been studied in the one-neutron knockout reaction ( ${}^{12}\mathrm{Be}{,}^{11}\mathrm{Be}+\ensuremath{\gamma}$) on a ${}^{9}\mathrm{Be}$ target at 78 MeV/nucleon. The resulting spectroscopic factors for the only two bound states of ${}^{11}\mathrm{Be}$ are $0.42\ifmmode\pm\else\textpm\fi{}0.06$ ( $1/{2}^{+}$) and $0.37\ifmmode\pm\else\textpm\fi{}0.06$ ( $1/{2}^{\ensuremath{-}}$), where the errors are experimental only. This result shows that $N\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}8$ is not a good closed shell in the neutron-rich ${}^{12}\mathrm{Be}$ and that the last neutron pair is two-thirds in the ( ${1s}^{2}{+0d}^{2}$) intruder configuration. |
| Databáze: | OpenAIRE |
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