Medium-spin excited states of the neutron-rich nucleus 87Br were observed and studied for the first time. They were populated in fission of 235U 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 πf5/2, π(p3/2+f5/2) and πg9/2 configurations. The behavior of the observed πg9/2 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 πg9/2 high-j proton polarizes the core.
@article{arxiv.2103.05291,
title = {Medium-spin states of the neutron-rich nucleus $^{87}$Br},
author = {B. M. Nyakó and J. Timár and M. Csatlós and Zs. Dombrádi and A. Krasznahorkay and I. Kuti and D. Sohler and T. G. Tornyi and M. Czerwiński and T. Rzcaca-Urban and W. Urban and P. Bcaczyk and L. Atanasova and D. L. Balabanski and K. Sieja and A. Blanc and M. Jentschel and U. Köster and P. Mutti and T. Soldner and G. de France and G. S. Simpson and C. A. Ur},
journal= {arXiv preprint arXiv:2103.05291},
year = {2021}
}