Browsing by Author "Lawrie, Elena A."

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    Exotic collective excitation patterns in triaxially deformed 131Ba
    (Institute of Physics, Chinese Academy of Sciences, 2024) Wei, Rui; Lawrie, Elena A.; Zhou, Hou-Bing
    In the last two decades, several unique phenomena in triaxially deformed nuclei, such as chiral doublet bands and wobbling motion have been revealed. Up to now, there are still many open questions which require further experimental and theoretical studies. To explore the collective motion in 131Ba, an experiment was performed using the XTU Tandem accelerator in the Legnaro laboratory, Italy. High-spin states of 131Ba have been populated via the heavy-ion fusion-evaporation 122Sn(13C, 4n) reaction. g-rays, charged particles and neutrons emitted from the residues were detected by the GALILEO array, EUCLIDES silicon ball, and the Neutron Wall, respectively. A total of 1.2 ×109 triple- or higher-fold events were collected by the GALILEO data acquisition system. The g-g-g coincidence events were sorted into a three-dimensional histogram (cube) and the analysis was carried out with the RADWARE and GASPWARE software packages. Through analysis of the coincidences between g-rays, the most comprehensive level schemes of 131Ba to date was deduced from the present work. The extended level-scheme consists of 15 rotational bands, and newly observed transitions are marked in red. Three nearly degenerate pairs of doublet bands (Band 3–8) are identified in 131Ba. Two pairs of chiral doublets (Band 3–6) with configuration πh11/2(g7/2,d5/2)×νh11/2 are interpreted as a set of pseudospin-chiral quartet bands.
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    Triaxiality and rotational bands in 133ce
    (University of Western Cape, 2021) Wakudyanaye, Ignasio; Lawrie, Elena A.; Orce, Jos e N.
    The neutron-de cient nuclei between the N = 50 and N = 82 shell closures provide rich information on the shape and structure of the nucleus. The isotones of 133Ce and 131Ba (N = 75) lie in this region of the nuclear chart. The properties of two recently discovered positive-parity rotational bands based on the g7=2 orbital were studied in this work. The rotational bands in both nuclei are based on the 7=2+ state. The quasiparticle+triaxial rotor (QTR) model was used to understand the dependence of the excitation energies and the signature splitting in these bands as a function of triaxiality. In addition to triaxiality, the e ects of the Coriolis interaction on the excitation energies and the signature splitting was also investigated.