Higher-spin structures inF21andNa25
| Autor: | J. M. VonMoss, P. C. Bender, Vandana Tripathi, Saul L. Miller, R. Dungan, D. D. Caussyn, B. Abromeit, J. J. Parker, Konstantinos Kravvaris, Alexander Volya, M. P. Kuchera, S. L. Tabor, P.-L. Tai, R. S. Lubna |
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| Rok vydání: | 2015 |
| Předmět: | |
| Zdroj: | Physical Review C. 92 |
| ISSN: | 1089-490X 0556-2813 |
| DOI: | 10.1103/physrevc.92.034301 |
| Popis: | Excited states were investigated in $^{21}\mathrm{F}$ and $^{25}\mathrm{Na}$ using the $^{9}\mathrm{Be}(^{14}\mathrm{C},pn\ensuremath{\gamma})$ reaction at 30, 35, and 45 MeV and the $^{9}\mathrm{Be}(^{18}\mathrm{O},pn\ensuremath{\gamma})$ reaction at 35 MeV. Protons were detected and identified in an $E\ensuremath{-}\mathrm{\ensuremath{\Delta}}E$ telescope at ${0}^{\ensuremath{\circ}}$ in coincidence with one or more $\ensuremath{\gamma}$ radiations in the FSU Compton-suppressed Ge detector array. Many new levels and electromagnetic decays were observed, especially among the higher spin states. Angular distributions and mean lifetimes were measured wherever possible in both nuclei. The energy levels of the positive-parity states in the two nuclei agree rather well with shell model calculations using both the USDA and WBP interactions up to the highest spins observed of $13/2\phantom{\rule{0.28em}{0ex}}\ensuremath{\hbar}$. Both a weak coupling approximation and shell model calculations using the WBP interaction generally reproduce the negative-parity states in $^{21}\mathrm{F}$. The shell model calculations reproduce relatively well the measured $M1$ and $E2$ transitions in both nuclei, but overpredict the parity-changing $E1$ transitions in $^{21}\mathrm{F}$, the only nucleus in which negative-parity states were observed in the present experiment. |
| Databáze: | OpenAIRE |
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