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Nuclear Theory·nucl-th

Monday·February 4, 2019

9 papers—4 primary·5 cross-listed

All9Primary4Cross-lists5
  1. 01

    [Submitted on 31 Jan 2019]

    Spectrum of light- and heavy-baryons

    Si-Xue Qin🇨🇳 · Craig D. Roberts🇺🇸 · Sebastian M. Schmidt🇩🇪

    A symmetry-preserving truncation of the strong-interaction bound-state equations is used to calculate the spectrum of ground-state , -baryons, where , their first positive-parity excitations and parity partners. Using two parameters, a description of the known spectrum of 39 such states is obtained, with a mean-absolute-relative-difference between calculation and experiment of 3.6(2.7)%. From this foundation, the framework is subsequently used to predict the masses of 90 states not yet seen empirically.

    Comments:
    18 pages, 4 figures, 4 tables. Contribution to a Special Issue of Few Body Systems, dedicated to Ludwig Faddeev
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    1902.00026 [pdf]
    Few Body Syst.(2019)·123 citations
  2. 02

    [Submitted on 31 Jan 2019]

    Unified description of pairing and quarteting correlations within the particle-hole-boson approach

    V.V. Baran · D.S. Delion

    We study the description of single-species and isovector pairing correlations in the framework of the projected-BCS (PBCS) and the Quartet Condensation Model (QCM) from a particle-hole perspective and we introduce the representation of the QCM quartet condensate state in terms of particle-hole excitations with respect to the Hartree-Fock state. We also present a new bosonic approximation for both PBCS and QCM. In each case, the starting point is the reformulation of the pair/quartet condensate state in terms of particle-hole excitations with respect to the Hartree-Fock state. The main simplification of our approach is the assumption that the pair operators corresponding to both particle and hole states obey bosonic commutation relations. This simplifies tremendously the computations and allows for an analytic derivation of the averaged Hamiltonian on the condenstate state as a function of the mixing amplitudes. We study both the pure bosonic approach and the renormalized version, and compare the particle-hole bosonic version to the naive prescription of applying the boson approximation directly to the original condensate state. We compare the fermionic and the renormalized particle-hole bosonic approach in the case of a picket fence model of doubly degenerate states and in a realistic shell model space with an effective interaction for the nuclei above Sn.

    Comments:
    17 pages, 8 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1902.00065 [pdf]
    PRC(2019)·6 citations
  3. 03

    [Submitted on 1 Feb 2019]

    Multiple chiral doublet bands with octupole correlations in reflection-asymmetric triaxial particle rotor model

    Y. Y. Wang · S. Q. Zhang · P. W. Zhao · J. Meng

    A reflection-asymmetric triaxial particle rotor model (RAT-PRM) with a quasi-proton and a quasi-neutron coupled with a reflection-asymmetric triaxial rotor is developed and applied to investigate the multiple chiral doublet (MD) bands candidates with octupole correlations in Br. The calculated excited energies, energy staggering parameters, and ratios are in a reasonable agreement with the data of the chiral doublet bands with positive- and negative-parity. The influence of the triaxial deformation on the calculated is found to be significant. By changing from 16 to 21, the values will be enhanced and better agreement with the data is achieved. The chiral geometry based on the angular momenta for the rotor, the valence proton and valence neutron is discussed in details.

    Comments:
    17 pages, 5 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1902.00191 [pdf]
    PLB(2019)·46 citations
  4. 04

    [Submitted on 1 Feb 2019]

    Evidence for Triangular D'(3h) Symmetry in 13C

    R. Bijker🇲🇽 · F. Iachello🇺🇸

    We derive the rotation-vibration spectrum of a 3alpha+1 neutron (proton) configuration with triangular D(3h) symmetry by exploiting the properties of the double group D'(3h), and show evidence for this symmetry to occur in the rotation-vibration spectra of 13C. Our results, based on purely symmetry considerations, provide benchmarks for microscopic calculations of the cluster structure of light nuclei.

    Comments:
    5 pages, 6 figures, 1 table, final version, accepted for publication in Physical Review Letters (2019)
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    1902.00451 [pdf]
    PRL(2019)·31 citations

Affiliations

first authorsco-authorsvia INSPIRE