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arXiv · 2103.05291

Medium-spin states of the neutron-rich nucleus $^{87}$Br

B. M. Nyakó·J. Timár·M. Csatlós·Zs. Dombrádi·A. Krasznahorkay·I. Kuti·D. Sohler·T. G. Tornyi·M. Czerwiński·T. Rzcaca-Urban·W. Urban·P. Bcaczyk·L. Atanasova·D. L. Balabanski·K. Sieja·A. Blanc·M. Jentschel·U. Köster·P. Mutti·T. Soldner·G. de France·G. S. Simpson·C. A. Ur
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Abstract

Medium-spin excited states of the neutron-rich nucleus $^{87}$Br were observed and studied for the first time. They were populated in fission of $^{235}$U induced by the cold-neutron beam of the PF1B facility of the Institut Laue-Langevin, Grenoble. The measurement of $γ$ radiation following fission has been performed using the EXILL array of Ge detectors. The observed level scheme was compared with results of large valence space shell model calculations. The medium-spin level scheme consists of three band-like structures, which can be understood as bands built on the $πf_{5/2}$, $π(p_{3/2}+f_{5/2})$ and $πg_{9/2}$ configurations. The behavior of the observed $πg_{9/2}$ band at high spins shows a considerable deviation from the shell model predictions. This deviation in this band is probably the result of an increased collectivity, which can be understood assuming that the $πg_{9/2}$ high-$\it j$ proton polarizes the core.

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B. M. Nyakó, J. Timár, M. Csatlós, Zs. Dombrádi, A. Krasznahorkay, I. Kuti, D. Sohler, T. G. Tornyi, M. Czerwiński, T. Rzcaca-Urban, W. Urban, P. Bcaczyk, L. Atanasova, D. L. Balabanski, K. Sieja, A. Blanc, M. Jentschel, U. Köster, P. Mutti, T. Soldner, G. de France, G. S. Simpson, C. A. Ur. 2021-03-09. Medium-spin states of the neutron-rich nucleus $^{87}$Br. https://doi.org/10.1103/physrevc.103.034304

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