Nature of seniority symmetry breaking in the semimagic nucleus 94 Ru

Das, B, Cederwall, B, Qi, C, Górska, M, Regan, PH, Aktas, Ö, Albers, HM, Banerjee, A, Chishti, MMR, Gerl, J
et al (show 77 more authors) (2022) Nature of seniority symmetry breaking in the semimagic nucleus 94 Ru. Physical Review C, 105 (3). l031304-.

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Direct lifetime measurements via γ-γ coincidences using a fast timing detector array consisting of LaBr3(Ce) scintillators has been applied to determine the lifetime of low-lying states in the semimagic (N=50) nucleus Ru94. The experiment was carried out as the first in a series of "FAIR-0"experiments with the DESPEC experimental setup at the Facility for Antiproton and Ion Research (FAIR). Excited states in Ru94 were populated primarily via the β-delayed proton emission of Pd95 nuclei, produced in the projectile fragmentation of an 850 MeV/nucleon Xe124 beam impinging on a 4 g/cm2Be9 target. While the deduced E2 strength for the 2+→0+ transition in the yrast cascade follows the expected behavior for conserved seniority symmetry, the intermediate 4+→2+ transition exhibits a drastic enhancement of transition strength in comparison with pure-seniority model predictions as well as standard shell model predictions in the fpg proton hole space with respect to doubly magic Sn100. The anomalous behavior is ascribed to a subtle interference between the wave function of the lowest seniority ν=2, Iπ=4+ state and that of a close-lying ν=4 state that exhibits partial dynamic symmetry. In addition, the observed strongly prohibitive 6+→4+ transition can be attributed to the same mechanism but with a destructive interference. It is noted that such effects may provide stringent tests of the nucleon-nucleon interactions employed in state-of-The-Art theoretical model calculations.

Item Type: Article
Divisions: Faculty of Science and Engineering > School of Physical Sciences
Depositing User: Symplectic Admin
Date Deposited: 20 Apr 2022 10:38
Last Modified: 17 Mar 2024 13:42
DOI: 10.1103/physrevc.105.l031304
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