1. Simultaneous impacts of nuclear shell structure and collectivity on $\beta$-decay: evidence from $^{80}$Ga$_{49}$
- Author
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Li, R., Verney, D., De Gregorio, G., Mancino, R., Matea, I., Coraggio, L., Itaco., N., Harakeh, M. N., Delafosse, C., Didierjean, F., Ayoubi, L. A., Falou, H. Al, Benzoni, G., Blanc, F. Le, Bozkurt, V., Ciemała, M., Deloncle, I., Fallot, M., Gaulard, C., Gottardo, A., Guadilla, V., Guillot, J., Hadyńska-Klęk, K., Ibrahim, F., Jovancevic, N., Kankainen, A., Lebois, M., Martínez, T., Napiorkowski, P., Roussiere, B., Sobolev, Yu. G., Stefan, I., Stukalov, S., Thisse, D., and Tocabens, G.
- Subjects
Nuclear Experiment - Abstract
The Gamow-Teller strength distribution covering the entire $\beta$-decay window, up to 10.312(4) MeV, of $^{80g+m}$Ga was measured for the first time in photo-fission of UC$_x$ induced by 50 MeV electron beam. The new data show significant enhancement in the high-energy region with a jump-structure. Simultaneously, the $\gamma$ de-exciting behavior of $\beta$-populated states presents a competition between de-excitation to 2$_1^+$ [$\beta_2$ = 0.155(9)] and to 2$_2^+$ [$\beta_2$ = 0.053$_{0.009}^{0.008}$)] in $^{80}$Ge. Based on these facts and combined with a realistic shell model calculation and systematic analysis of logft ratio between precursor $\beta$-decay to 2$_2^+$ and to 2$_1^+$ of Ga isotopes, we conclude that these phenomena evidence simultaneous impacts of nuclear shell structure and collectivity on B(GT) and its distribution and, therefore, the half-life of the precursor. These data prove that the nucleus as a multi-nucleon correlated quantum system reacts as a whole when $\beta$-decay occurs in contrast to simple single-particle excitation. Additionally, the comparison with the theoretical results evidence how challenging is the description of the experimental data obtained, and render this experimental outcome a sound test for the theoretical models.
- Published
- 2024