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Nuclear Theory·nucl-th

Thursday·January 13, 2022

10 papers—6 primary·4 cross-listed

All10Primary6Cross-lists4
  1. 01

    A semimicroscopic description of Isoscalar Giant Multiple Resonances in medium-mass closed-shell nuclei

    M.L. Gorelik · S. Shlomo · B.A. Tulupov · M.H. Urin

    Main properties of isoscalar giant multipole resonances (up to L=3), including L=0,2 overtones, in medium-mass closed-shell nuclei are described within the semimicroscopic particle-hole dispersive optical model. Main properties are characterized by the energy-averaged strength distribution, projected (one-body) transition density, and probabilities of direct one-nucleon decay. Calculation results obtained for the parameters of the mentioned resonances in the 48Ca, 90Zr, and 132Sn nuclei are compared with available experimental data.

    nucl-thPRC(2023)·7 citations
  2. 02

    Large enhancement of total reaction cross sections at the edge of the island of inversion in Ti, Cr, and Fe isotopes

    W. Horiuchi · T. Inakura · S. Michimasa

    A systematic analysis of nuclear deformation is made for neutron-rich Ti, Cr, and Fe isotopes to explore the nuclear structure in the island of inversion near N = 40, where strong nuclear deformation is predicted. The nuclear ground states are obtained by the Skyrme Hartree-Fock method in three-dimensional coordinate space, which properly describes any nuclear shape. Three types of Skyrme interactions are employed to generate various deformed states in its isotopic chain. We find that in the island of inversion the occupation of highly elongated intruder orbits induces not only large quadrupole deformation but also large hexadecapole deformation. This appears as a sizable enhancement of the nuclear matter radius, showing the characteristic shell effect of the density profile near the nuclear surface. We show that the edge of the island of inversion, where the intruder orbit starts being occupied, can be determined by measuring the enhancement of the total reaction cross section at high incident energy. The possibility of constraining the hexadecapole deformation by a measurement of the total reaction cross sections is discussed.

    nucl-thnucl-exPRC(2022)·14 citations
  3. 03

    Diabatic Hamiltonian matrix elements made simple

    K. Hagino · G.F. Bertsch

    With a view to applying the Generator Coordinate Method to large configuration spaces, we propose a simple approximate formula to compute diabatic many-body matrix elements without having to evaluate two-body interaction matrix elements. The method is illustrated with two analytically solvable Hamiltonians based on the harmonic oscillator.

    nucl-thPRC(2022)·6 citations
  4. 04

    Global polarization in heavy-ion collisions at energies 2.4--7.7 GeV: Effect of Meson-Field Interaction

    Yu. B. Ivanov🇷🇺 · A. A. Soldatov🇷🇺

    Based on the three-fluid model, the global polarization in Au+Au collisions at 2.4 7.7 GeV is calculated, including its rapidity and centrality dependence. Contributions from the thermal vorticity and meson-field term (proposed by Csernai, Kapusta and Welle) to the global polarization are considered. The results are compared with data from recent and ongoing STAR and HADES experiments. It is predicted that the polarization maximum is reached at 3 GeV, if the measurements are performed with the same acceptance. The value of the polarization is very sensitive to interplay of the aforementioned contributions. In particular, the thermal vorticity results in quite strong increase of the polarization from the midrapidity to forward/backward rapidities, while the meson-field contribution considerably flattens the rapidity dependence. The polarization turns out to be very sensitive to details of the equation of state. While collision dynamics become less equilibrium with decreasing collision energy, the present approach to polarization is based on the assumption of thermal equilibrium. It is found that equilibrium is achieved at the freeze-out stage, but this equilibration takes longer at moderately relativistic energies.

    nucl-thhep-phnucl-exPRC(2022)·17 citations
  5. 05

    The yield ratio of anti-nuclei and nuclei of relativistic nuclear collisions in the central rapidity region

    A.I Malakhov🇷🇺 · A.A. Zaitsev🇷🇺

    This article describes calculations of the yield ratio of anti-particles to the yield of particles (, ,/He) in proton-proton and nuclear-nuclear interactions using the self-similarity parameter in the central rapidity region. The used approach is based on the study of relativistic nuclear interactions in the four-velocity space. The results of the calculations are compared with the existing experimental data in a wide center-of-mass energy range (, , ). Within this approach the inclusive spectra of pions and kaons and ratios of their yields in collisions have been successfully described earlier.

    nucl-thnucl-exJ.Exp.Theor.Phys.(2022)·2 citations
  6. 06

    Theoretical Methods for Giant Resonances

    Gianluca Colo'

    The Random Phase Approximation (RPA) and its variations and extensions are, without any doubt, the most widely used tools to describe Giant Resonances within a microscopic theory. In this chapter, we will start by discussing how RPA comes out naturally if one seeks a state with a harmonic time dependence in the space of one particle-one hole excitations on top of the ground state. It will be also shown that RPA is the simplest approach in which a ``collective'' state emerges. These are basic arguments that appear in other textbooks but are also unavoidable as a starting point for further discussions. In the rest of the chapter, we will give emphasis to developments that have taken place in the last decades: alternatives to RPA like the Finite Amplitude Method (FAM), state-of-the-art calculations with well-established Energy Density Functionals (EDFs), and progress in {\em ab initio} calculations. We will discuss extensions of RPA using as a red thread the various enlargements of the one particle-one hole model space. The importance of the continuum, and the exclusive observables like the decay products of Giant Resonances, will be also touched upon.

    nucl-thnucl-ex6 citations

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first authorsco-authorsvia INSPIRE