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Nuclear Theory·nucl-th

Friday·December 8, 2023

12 papers—5 primary·7 cross-listed

All12Primary5Cross-lists7
  1. 01

    [Submitted on 6 Dec 2023]

    Excitation of multipolar transitions in nuclei by twisted photons

    P.O. Kazinski · A.A. Sokolov

    The explicit expression for the probability of absorption of a twisted photon by an atomic nucleus has been obtained. It is shown that photoabsorption obeys the selection rule , where is the multipolarity of the nuclear transition, when the nuclei lie near the axis along which a twisted photon with a projection of the total angular momentum propagates. In the long-wave limit, the main contribution to the probability of absorption of a twisted photon comes from the multipole transition with . The absorption coefficient for twisted photons in a target consisting of many nuclei has been found.

    Comments:
    15 pp; some misprints corrected
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2312.03803 [pdf]
    Phys.Atom.Nucl.(2024)·10 citations
  2. 02

    [Submitted on 6 Dec 2023]

    On the Destabilization of High-Mass Neutron Stars by the Emergence of -Hexaquarks

    Marcos O. Celi🇦🇷 · Mikhail Bashkanov🇬🇧 · Mauro Mariani🇦🇷 · Milva G. Orsaria🇦🇷 · Alessandro Pastore🇫🇷 · Ignacio F. Ranea-Sandoval🇦🇷 · Fridolin Weber🇺🇸

    We study the effects of the first nontrivial hexaquark, (2380), on the equation of state of dense neutron star matter and investigate the consequences of its existence for neutron stars. The matter in the core regions of neutron stars is described using density-dependent relativistic mean-field theory. Our results show that within the parameter spaces examined in our paper, (i) the critical density at which the condensate emerges lies between 4 and 5 times the nuclear saturation density, (ii) hexaquarks are found to exist only in rather massive neutron stars, (iii) only relatively small fractions of the matter in the core of a massive neutron star may contain hexaquarks.

    Comments:
    15 pages, 7 figures. Accepted for publication in Physical Review D
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
    arXiv:
    2312.03880 [pdf]
    PRD(2024)·12 citations
  3. 03

    [Submitted on 7 Dec 2023]

    Global density-dependent -nucleon interaction for -nucleus elastic scattering

    T. Furumoto · K. Tsubakihara · S. Ebata · W. Horiuchi

    We provide a global density-dependent He-nucleon (DD-) interaction to construct the -nucleus optical model potential (OMP) in a wide range of incident energies. The global parametrization for the DD- interaction is obtained based on the proton-He OMP which reproduces the elastic scattering cross-section data very well in the incident energies of 12.04--500 MeV per nucleon. We derive the -nucleus potential by a folding procedure with the point-nucleon density obtained by a microscopic mean-field model using the present DD- interaction. The density dependence of the DD- interaction is fixed phenomenologically to reproduce the -nucleus elastic scattering cross-section data by the O, Ca, Ni, Zr, and Pb targets at 10--342.5 MeV. We also show the total reaction cross sections, which are helpful in fixing one free parameter, the renormalization factor for the imaginary part of the -nucleus potential. Lastly, we show some examples, which clearly demonstrate the validity and power of the present DD- approach.

    Comments:
    20 pages, 11 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2312.03960 [pdf]
    PTEP(2024)·2 citations
  4. 04

    [Submitted on 7 Dec 2023]

    The charge density and neutron skin thickness of Skyrmions

    Alberto García Martín-Caro🇪🇸 · Chris Halcrow🇸🇪

    Motivated by recent parity violating electron scattering experiments, we compute the Neutron Skin Thickness (NST) of nuclei modelled as (quantized) Skyrmions, the topological solitons of the Skyrme model. We show how in a certain approximation, the result for the NST is oblivious to the fine details of the (generally very complicated) quantum state of the soliton and only depends on the total baryon number and the isospin number. Moreover, in the leading order, the linear dependence on the asymmetry parameter is recovered, as expected both from experimental data and other models of nuclei such as the liquid drop model.

    Comments:
    14 pages, 7 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Theory (hep-th)
    arXiv:
    2312.04335 [pdf]
    4 citations
  5. 05

    [Submitted on 6 Dec 2023]

    Multimodality of Ir fission studied by Langevin approach

    Y.G. Huang · F.C. Gu · Y.J. Feng · H. Wang · E.X. Xiao · X. Lei · L. Zhu · J. Su

    [Background] The fission mechanism of sub-lead nuclides remains unclear, especially the types of fission modes involved and their corresponding shell effects. [Purpose] The aim is to identify the different modes in the fission of Ir, and investigate the corresponding mechanism. [Method] The three-dimensional Langevin approach considering nucleus elongation, deformation, and mass asymmetry is applied to simulate fission dynamics. The macro-microscopic models are used to calculate the transport coefficients. [Results] The fragment mass, deformation, and total kinetic energy (TKE) of Ir fission at different excitation energies are calculated. Based on the mass-TKE correlations, four fission modes are identified, namely two asymmetric standard modes, a symmetric super-long mode, and a symmetric liquid-drop mode. Strong excitation-energy resistance of two asymmetric modes is found. The mass distributions show the dominance of single-peak shape, which is in good agreement with experimental data. The fission potential energy surface and the fission dynamics are analyzed to investigate the origins of the modes and the competition between neutron and proton shell effects. [Conclusions] Multiple fission modes are included in the Ir fission behind the single-peak-like distribution of observables. The proton and neutron magic numbers with different asymmetry parameter might heighten the sensitivity to the uncertainties of shell corrections.

    Comments:
    18 pages, 9 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2312.04568 [pdf]
    PRC(2024)·4 citations

Affiliations

first authorsco-authorsvia INSPIRE