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Nuclear Theory·nucl-th

Friday·February 7, 2020

13 papers—7 primary·6 cross-listed

All13Primary7Cross-lists6
  1. 01

    [Submitted on 6 Feb 2020]

    Two quasiparticle wobbling in the even-even nucleus 130Ba

    Y. K. Wang · F. Q. Chen · P. W. Zhao

    Two newly observed bands built on a two-quasiparticle configuration in 130Ba have been investigated for the first time with the microscopic projected shell model. The experimental energy spectra and the available electromagnetic transition probabilities are well reproduced. The wobbling character of the higher band is revealed by the angular momentum projected wavefunctions via the K plot and the azimuthal plot. This provides the first strong microscopic evidence for wobbling motion based on a two-quasiparticle configuration in even-even nuclei.

    Comments:
    12 pages, 4 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2002.02093 [pdf]
    PLB(2020)·29 citations
  2. 02

    [Submitted on 6 Feb 2020]

    Application of the coherent density fluctuation model to study the nuclear matter properties of finite nuclei within the relativistic mean-field formalism

    Ankit Kumar🇮🇳 · H. C. Das🇮🇳 · Manpreet Kaur🇮🇳 · M. Bhuyan🇲🇾 · S. K. Patra🇮🇳

    We obtained a density-dependent analytical expression of binding energy per nucleon for different neutron-proton asymmetry of the nuclear matter (NM) with a polynomial fitting, which manifests the results of effective field theory motivated relativistic mean-field (E-RMF) model. This expression has the edge over the Brckner energy density functional [Phys. Rev. {\bf 171}, 1188 (1968)] since it resolves the Coster-Band problem. The NM parameters like incompressibility, neutron pressure, symmetry energy, and its derivatives are calculated using the acquired expression of energy per nucleon. Further, the weight function calculated by E-RMF densities are folded with calculated NM parameters within coherent density fluctuation model to find the properties of closed/semi-closed-shell even-even O, Ca, Ca, Ni, Zr, Sn, and Pb nuclei. The values obtained for the neutron pressure , symmetry energy and its derivative known as slope parameter, lie within a narrow domain whereas there is a large variation in isoscalar incompressibility and surface incompressibility while moving from light to heavy nuclei. The sizable variation in and for light and heavy nuclei depicts their structural dependence due to the peculiar density distribution of each nucleus. A comparison of surface quantities calculated in the present work has also been made with ones obtained via Brckner energy density functional.

    Comments:
    8 pages, 5 figures, 3 tables. Published in Phys. Rev. C 103 , 024305 (2021)
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2002.02135 [pdf]
    PRC(2021)·13 citations
  3. 03

    [Submitted on 6 Feb 2020]

    Ab initio computation of charge densities for Sn and Xe isotopes

    P. Arthuis🇬🇧 · C. Barbieri🇬🇧 · M. Vorabbi🇺🇸 · P. Finelli🇮🇹

    We present the first ab initio calculations for open-shell nuclei past the tin isotopic line, focusing on Xe isotopes as well as doubly-magic Sn isotopes. We show that, even for moderately hard interactions, it is possible to obtain meaningful predictions and that the NNLOsat chiral interaction predicts radii and charge density distributions close to the experiment. We then make a new prediction for Sn. This paves the way for ab initio studies of exotic charge density distributions at the limit of the present ab initio mass domain, where experimental data is becoming available. The present study closes the gap between the largest isotopes reachable by ab initio methods and the smallest exotic nuclei accessible to electron scattering experiments.

    Comments:
    6 pages, 4 figures and 2 tables
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2002.02214 [pdf]
    PRL(2020)·68 citations
  4. 04

    [Submitted on 5 Feb 2020]

    Nuclear effects in proton transport and dose calculations

    Francesc Salvat · José Manuel Quesada

    Interactions of protons with nuclei are modeled in a form that is suitable for Monte Carlo simulation of proton transport. The differential cross section (DCS) for elastic collisions of protons with neutral atoms is expressed as the product of the Rutherford DCS, which describes scattering by a bare point nucleus, and two correction factors that account for the screening of the nuclear charge by the atomic electrons and for the effect of the structure of the nucleus. The screening correction is obtained by considering the scattering of the projectile by an atom with a point nucleus and the atomic electron cloud described by a parameterization of the Dirac-Hartree-Fock-Slater self-consistent electron density. The DCS for scattering by this point nucleus atom is calculated by means of the eikonal approximation. The nuclear correction to the DCS for elastic collisions is calculated by conventional partial-wave analysis with a global optical-model potential that describes the interaction with the bare nucleus. Inelastic interactions of the projectile with target nuclei are described by using information from data files in ENDF-6 format, which provide cross sections, multiplicities, and angle-energy distributions of all reaction products: light ejectiles (neutrons, protons, . . . ), gammas, as well as recoiling heavy residuals. These interaction data have been used in the Monte Carlo transport code PENH, an extension of the electron-gamma code PENELOPE, which originally accounted for electromagnetic interactions only. The combined code system PENH/PENELOPE performs simulations of coupled electron-photon-proton transport. A few examples of simulation results are presented to reveal the influence of nuclear interactions on proton transport processes and on the calculation of dose distributions from proton beams.

    Subjects:
    Nuclear Theory (nucl-th); physics.app-ph (physics.app-ph); Atomic Physics (physics.atom-ph)
    arXiv:
    2002.02300 [pdf]
    Nucl.Instrum.Meth.B(2020)·4 citations
  5. 05

    [Submitted on 6 Feb 2020]

    Beyond-mean-field effects on the symmetry energy and its slope from the low-lying dipole response of Ni

    M. Grasso🇫🇷 · D. Gambacurta🇮🇹

    We study low-energy dipole excitations in the unstable nucleus Ni with the beyond-mean-field (BMF) subtracted second random-phase-approximation (SSRPA) model based on Skyrme interactions. First, strength distributions are compared with available experimental data and transition densities of some selected peaks are analyzed. The so-called isospin splitting is also discussed by studying the isoscalar/isovector character of such excitations. We estimate then in an indirect way BMF effects on the symmetry energy of infinite matter and on its slope starting from the BMF SSRPA low-lying strength distribution. For this, several linear correlations are used, the first one being a correlation existing between the contribution (associated with the low-energy strength) to the total energy-weighted sum rule (EWSR) and the slope of the symmetry energy. BMF estimates for the slope of the symmetry energy can be extracted in this way. Correlations between such a slope and the neutron-skin thickness of Ni and correlations between the neutron-skin thickness of Ni and the electric dipole polarizability times the symmetry energy are then used to deduce BMF effects on the symmetry energy.

    Comments:
    10 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2002.02331 [pdf]
    PRC(2020)·12 citations
  6. 06

    [Submitted on 5 Feb 2020]

    A theoretical approach to study J/ suppression in relativistic heavy ion collisions

    Santosh K. Karn (Department of Physics, School of Basic Sciences and Research, Sharda University)🇮🇳

    With a view to understanding J/ suppression in relativistic heavy ion collisions, we compute the suppression rate within the framework of hydrodynamical evolution model. For this, we consider an ellipsoidal flow and use an ansatz for temperature profile function which accounts for time and the three dimensional space evolution of the quark-gluon plasma. We have calculated the survival probability separately as the function of transverse and longitudinal momentum. We have shown that previous calculations are special cases of this model.

    Comments:
    06 pages
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2002.02412 [pdf]
    Open J.Microphys.(2020)·0 citations
  7. 07

    [Submitted on 6 Feb 2020]

    Constraints and correlations of nuclear matter parameters from a density-dependent van der Waals model

    M. Dutra · B. M. Santos · O. Lourenço

    A recently proposed density-dependent van der Waals model, with only free parameters adjusted to fix binding energy, saturation density, symmetry energy, and incompressibility, is analyzed under symmetric and asymmetric nuclear matter constraints. In a previous paper, it was shown that this model is fully consistent with the constraints related to the binary neutron star merger event named GW170817 and reported by the LIGO and Virgo collaboration. Here, we show that it also describes satisfactorily the low and high-density regions of symmetric nuclear matter, with all the main constraints satisfied. We also found a linear correlation between the incompressibility and the skewness parameter, both at the saturation density and show how it relates to the crossing point presented in the incompressibility as a function of the density. In the asymmetric matter regime, other linear correlations are found, namely, the one between the symmetry energy () and its slope (), and other one establishing the symmetry energy curvature as a function of the combination given by .

    Comments:
    20 pages, 7 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2002.02437 [pdf]
    J.Phys.G(2020)·12 citations

Affiliations

first authorsco-authorsvia INSPIRE