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Nuclear Theory·nucl-th

Thursday·July 11, 2024

10 papers—3 primary·7 cross-listed

All10Primary3Cross-lists7
  1. 01

    [Submitted on 22 Jun 2024]

    Mean-field derived IBM-1 Hamiltonian with intrinsic triaxial deformation

    Polytimos Vasileiou (1) · Dennis Bonatsos (2) · Theo J. Mertzimekis (1) ((1) Department of Physics, National & Kapodistrian University of Athens, Zografou Campus, Greece, (2) Institute of Nuclear and Particle Physics, National Center for Scientific Research "Demokritos'', Aghia Paraskevi, Greece)

    An interacting-boson-model-1 (IBM-1) Hamiltonian, derived from self-consistent mean-field calculations using a Skyrme energy density functional is employed for the study of energy spectra and transition strengths in the even-even and . An intrinsic triaxial deformation, derived from fermionic proxy-SU(3) irreps, is incorporated into the IBM-1 potential energy curve, which is subsequently mapped to the fermionic one, in order to derive the parameters of the IBM-1 Hamiltonian. It is shown that the inclusion of the intrinsic triaxial deformation derived from the proxy-SU(3) irreps leads to a significantly improved agreement between the theoretical predictions and experimental data for the low-lying quadrupole bands in the examined isotopes, without the need of higher-order terms in the IBM-1 Hamiltonian. The calculated transition strengths are also improved, compared to the axially symmetric case. The recently suggested preponderance of triaxial deformation over extended regions of the nuclear chart is obtained as a by-product. Future potential improvements and extensions to this mapping approach are also discussed.

    Comments:
    20 pages, 9 figures. Accepted for publication to Phys. Rev. C
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2407.07101 [pdf]
    PRC(2024)·6 citations
  2. 02

    [Submitted on 9 Jul 2024]

    Triply-heavy/strange baryons with Cornell potential on a quantum computer

    Nicolás Martínez de Arenaza🇪🇸 · Juan J. Gálvez-Viruet🇪🇸 · Felipe J. Llanes-Estrada (Univ. Complutense de Madrid)🇪🇸

    We present a computation of triply-heavy baryons on a quantum computer, employing the Cornell quark model in line with the earlier quarkonium work of Gallimore and Liao. These baryons are some of the most interesting Standard Model particles which have not yet been detected, as they bear on the short range (colour) behaviour of the nuclear force. The spectrum here obtained is compatible with predictions from earlier works, with our uncertainty dominated by traditional few-body approximations (size of the variational basis, center of mass recoil, parameter estimation...) and not by the statistical error from the quantum computer (deployed here as a small diagonalizer), which turns out to be negligible respect to the other sources of uncertainty, at least in the present unsophisticated few-body approximation. We have also substituted one or more heavy quarks for strange quarks.

    Comments:
    16 pages, 7 plots, uses quantikz2
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2407.07232 [pdf]
    EPJA(2024)·11 citations
  3. 03

    [Submitted on 8 Jul 2024]

    Angular anisotropy of secondary neutron spectra in Th+n

    V.M. Maslov

    Neutron emission spectra (NES) of Th+n interaction provide strong evidence of angular anisotropy of secondary neutron emission, another evidence might be predicted in Th%(n,F)% prompt fission neutron spectra (PFNS). In case of NES observed angular anisotropy is presumably due to angular dependence of elastic scattering, direct excitation of collective levels and preequilibrium emission of (n,nX) neutrons. In Th+n direct excitation data analysis, ground state band levels are coupled within rigid rotator model, while those of beta bands, gamma bands and octupole band theta are coupled within soft deformable rotator model. NES of Th+n at En of 6, 12, 14, 18 MeV exhaustively described. The net effect of these procedures for En up to 20 MeV is the adequate approximation of angular distributions of Th first neutron inelastic scattering in continuum, which corresponds to U of 1.2-6 MeV excitations of Th. The contribution of Th PFNS to the NES is exceptionally low. PFNS anisotropy occurs because some portion of neutrons might be involved in exclusive prefission neutron spectra. In Th reactions PFNS demonstrate different response to forward and backward (n,xnf) neutron emission relative to the incident neutron momentum, when compared with U or 239Pu(n,xnf) reactions. Average energy of (n,xnf) neutrons depends on the neutron emission angle theta, i.e. fission cross section, prompt neutron number and total kinetic energy are shown to vary with the angle theta as well. Exclusive neutron spectra ( at theta equal to 90 degrees are consistent with observed Th and Th reaction cross sections within En from 1 to 20 MeV energy range.

    Comments:
    16 pages, 8 figures. arXiv admin note: text overlap with arXiv:2407.06242
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2407.07274 [pdf]
    0 citations

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first authorsco-authorsvia INSPIRE