Enhanced Electric Dipole Strength for the Weakly Bound States in Ne27
| Autor: | I. Syndikus, Brenden Longfellow, Naofumi Tsunoda, P. C. Bender, Brandon Elman, H. Iwasaki, E. Lunderberg, C. Loelius, Takaharu Otsuka, B. A. Brown, N. Kobayashi, A. Hufnagel, D. Weisshaar, Marina Petri, M. Grinder, D. Bazin, R. Elder, Alexandra Gade, K. Whitmore, Sebastian Heil, M. Mathy, J. Belarge |
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| Rok vydání: | 2018 |
| Předmět: | |
| Zdroj: | Physical Review Letters. 121 |
| ISSN: | 1079-7114 0031-9007 |
| Popis: | An enhanced low-energy electric dipole ($E1$) strength is identified for the weakly bound excited states of the neutron-rich isotope $^{27}\mathrm{Ne}$. The Doppler-shift lifetime measurements employing a combination of the $\ensuremath{\gamma}$-ray tracking array GRETINA, the plunger device, and the S800 spectrograph determine the lower limit of $0.030\text{ }\text{ }{e}^{2}\text{ }{\mathrm{fm}}^{2}$ or 0.052 W.u. for the $1/{2}^{+}\ensuremath{\rightarrow}3/{2}^{\ensuremath{-}}\text{ }\text{ }E1$ transition in $^{27}\mathrm{Ne}$, representing one of the strongest $E1$ strengths observed among the bound discrete states in this mass region. This value is at least 30 times larger than that measured for the $3/{2}^{\ensuremath{-}}$ decay to the $3/{2}_{gs}^{+}$ ground state. A comparison of the present results to large-scale shell-model calculations points to an important role of core excitations and deformation in the observed $E1$ enhancement, suggesting a novel example of the electric dipole modes manifested in weakly bound deformed systems. |
| Databáze: | OpenAIRE |
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