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Nuclear Theory·nucl-th

Monday·September 11, 2023

7 papers—3 primary·4 cross-listed

All7Primary3Cross-lists4
  1. 01

    [Submitted on 8 Sept 2023]

    Efimov states in excited nuclear halos

    Shimpei Endo · Junki Tanaka

    Universality -- an essential concept in physics -- implies that different systems show the same phenomenon and can be described by a unified theory. A prime example of the universal quantum phenomena is the Efimov effect, which is the appearance of multiples of low-energy three-body bound states with progressively large sizes dictated by the discrete scale invariance. The Efimov effect, originally proposed in the nuclear physics context, has been observed in cold atoms and molecules. The search for the Efimov effect in nuclear physics, however, has been a long-standing challenge owing to the difficulty in identifying ideal nuclides with a large -wave scattering length; such nuclides can be unambiguously considered as Efimov states. Here, we propose a systematic method to identify nuclides that exhibit Efimov states in their excited states in the vicinity of the neutron separation threshold. These nuclei are characterised by their enormous low-energy neutron capture cross-sections, hence giant -wave scattering length. Using our protocol, we identified Zr and Gd as novel candidate nuclides that show the Efimov states. They are well inside the valley of stability in the nuclear chart, and are suited for experimental realisation of the Efimov states in nuclear physics.

    Comments:
    13 pages, 3 figures, 2 tables
    Subjects:
    Nuclear Theory (nucl-th); Quantum Gases (cond-mat.quant-gas); Nuclear Experiment (nucl-ex)
    arXiv:
    2309.04131 [pdf]
    4 citations
  2. 02

    [Submitted on 8 Sept 2023]

    Microscopic optical potentials for medium-mass isotopes derived at the first order of the Watson multiple scattering theory

    Matteo Vorabbi🇬🇧 · Carlo Barbieri🇮🇹 · Vittorio Somà🇫🇷 · Paolo Finelli🇮🇹 · Carlotta Giusti🇮🇹

    We perform a first-principle calculation of optical potentials for nucleon elastic scattering off medium-mass isotopes. Fully based on a saturating chiral Hamiltonian, the optical potentials are derived by folding nuclear density distributions computed with ab initio self-consistent Green's function theory with a nucleon-nucleon matrix computed with a consistent chiral interaction. The dependence on the folding interaction as well as the convergence of the target densities are investigated. Numerical results are presented and discussed for differential cross sections and analyzing powers, with focus on elastic proton scattering off Calcium and Nickel isotopes. Our optical potentials generally show a remarkable agreement with the available experimental data for laboratory energies in the range 65-200 MeV. We study the evolution of the scattering observables with increasing proton-neutron asymmetry by computing theoretical predictions of the cross section and analyzing power over the Calcium and Nickel isotopic chains.

    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2309.04226 [pdf]
    PRC(2024)·15 citations
  3. 03

    [Submitted on 8 Sept 2023]

    Microscopic analysis of dipole electric and magnetic strengths in Gd

    V.O. Nesterenko · P.I. Vishnevskiy · P.-G. Reinhard · A. Repko · J. Kvasil

    The dipole electric () and magnetic () strengths in strongly deformed Gd are investigated within a fully self-consistent Quasiparticle Random Phase Approximation (QRPA) with Skyrme forces SVbas, SLy6 and SG2. We inspect, on the same theoretical footing, low-lying dipole states and the isovector giant dipole resonance in channel and the orbital scissors resonance as well as the spin-flip giant resonance (SFGR) in channel. Besides, toroidal mode and low-energy spin-flip excitations are considered. The deformation splitting and dipole-octupole coupling of electric excitations are analyzed. The origin of SFGR gross structure, impact of the residual interaction and interference of orbital and spin contributions to SFGR are discussed. The effect of the central exchange -term from the Skyrme functional is demonstrated. The calculations show a satisfactory agreement with available experimental data, except for the recent NRF measurements of M. Tamkas et al for strength at 4-6 MeV, where, in contradiction with our calculations and previous data, almost no strength was observed.

    Comments:
    13 pages, 6 figures, 8 tables
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2309.04294 [pdf]
    EPJA(2024)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE