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Nuclear Theory·nucl-th

Friday·September 15, 2023

10 papers—2 primary·8 cross-listed

All10Primary2Cross-lists8
  1. 01

    [Submitted on 14 Sept 2023]

    At the borderline of shape coexistence: Mo and Ru

    E. Maya-Barbecho · S. Baid · J.M. Arias · J.E. García-Ramos

    Background Even-even isotopes of Mo () and Ru () are nuclei close to the subshell closure at , where shape coexistence plays a significant role. As a result, their spectroscopic properties are expected to resemble those of Sr () and Zr (). Exploring the evolution of these properties as they move away from the subshell closure is of great interest. Purpose The purpose of this study is to reproduce the spectroscopic properties of even-even Mo and Ru isotopes and to determine the influence of shape coexistence. Method We have employed the interacting boson model with configuration mixing as the framework to calculate all the observables for Mo and Ru isotopes. We have considered two types of configurations: 0-particle-0-hole and 2-particle-2-hole excitations. The model parameters have been determined using a least-squares fitting to match the excitation energies and the transition rates. Results We have obtained the excitation energies, values, two-neutron separation energies, nuclear radii, and isotope shifts for the entire chain of isotopes. Our theoretical results have shown good agreement with experimental data. Furthermore, we have conducted a detailed analysis of the wave functions and obtained the mean-field energy surfaces and the nuclear deformation parameter, , for all considered isotopes. Conclusions Our findings reveal that shape coexistence plays a significant role in Mo isotopes, with the crossing of intruder and regular configurations occurring at neutron number (), which induces a quantum phase transition. In contrast, in Ru isotopes, the intruder states have minimal influence, remaining at higher energies. However, at neutron number , also a quantum phase transition occurs in Ru isotopes.

    Comments:
    Accepted for publication in Physical Review C. arXiv admin note: text overlap with arXiv:2203.05324
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2309.07426 [pdf]
    PRC(2023)·10 citations
  2. 02

    [Submitted on 14 Sept 2023]

    Shell-model study for allowed and forbidden decay properties in the mass region "south" of Pb

    Shweta Sharma · Praveen C. Srivastava · Anil Kumar · Toshio Suzuki · Cenxi Yuan · Noritaka Shimizu

    The large-scale shell-model calculations have been performed for the neutron-rich nuclei in the south region of Pb in the nuclear chart. The -decay properties, such as the , average shape factor values, half-lives, and partial decay rates are calculated for these neutron-rich nuclei using recent effective interaction for the Pb region. These calculations have been performed without truncation in a particular model space for nuclei ; additionally, particle-hole excitations are included in the case of core-breaking nuclei (). An extensive comparison with the experimental data has been made, and spin parities of several states have been proposed.

    Comments:
    16 pages, 6 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2309.07903 [pdf]
    PRC(2024)·6 citations

Affiliations

first authorsco-authorsvia INSPIRE