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Nuclear Theory·nucl-th

Thursday·September 17, 2015

9 papers—4 primary·5 cross-listed

All9Primary4Cross-lists5
  1. 01

    [Submitted on 16 Sept 2015]

    In-medium and isospin effects on particle production near threshold energies in heavy-ion collisions

    Zhao-Qing Feng🇨🇳 · Wen-Jie Xie🇨🇳 · Peng-Hui Chen🇨🇳 · Jie Chen🇨🇳 · Gen-Ming Jin🇨🇳

    Dynamics of pseudoscalar mesons (, , and ) and hyperons ( and ) produced in heavy-ion collisions near threshold energies has been investigated within the Lanzhou quantum molecular dynamics (LQMD) transport model. The in-medium modifications on particle production in dense nuclear matter are implemented in the model through corrections on the elementary cross sections and by inclusion of the meson (hyperon)-nucleon potentials, in which the isospin effects are considered. It is found that the transportation of particles are influenced with the in-medium corrections. The total number of pions is reduced with an isospin, density and momentum dependent pion-nucleon potential. However, the ratios of charged pions is enhanced with inclusion of the potential. The production of eta in the domain of mid-rapidities and high momenta is sensitive to the -nucleon potential, but weakly depends on symmetry energy. The attractive antikaon-nucleon potential enhances the subthreshold production and also influences the structure of phase-space distributions. Dynamics of etas, kaons, antikaons and hyperons is also influenced by the pion potential because of collisions between pions and nucleons (resonances). The impacts of mean-field potentials on particle dynamics are investigated, such as the phase-space distributions from rapidity and transverse momentum spectra, inclusive invariant spectra, collective flows etc.

    Comments:
    18 pages, 13 figures. arXiv admin note: text overlap with arXiv:1310.8072
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1509.04792 [pdf]
    PRC(2015)·35 citations
  2. 02

    [Submitted on 16 Sept 2015]

    Effects of potentials on nuclides in the A100-120 region

    C. Lahiri · S. K. Biswal · S. K. Patra

    Microscopic optical potentials for low energy proton reactions have been obtained by folding density dependent M3Y interaction derived from nuclear matter calculation with densities from mean field approach to study astrophysically important proton rich nuclei in mass 100-120 region. We compare S factors for low-energy reactions with available experimental data and further calculate astrophysical reaction rates for and reactions. Again we choose some nonlinear R3Y interactions from RMF calculation and folded them with corresponding RMF densities to reproduce experimental S factor values in this mass region. Finally the effect of nonlinearity on our result is discussed.

    Comments:
    9 pages, 10 figures, 2 tables
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1509.04816 [pdf]
    IJMPE(2016)·24 citations
  3. 03

    [Submitted on 16 Sept 2015]

    Effect of Delta potential on the pion-/pion+ ratio in heavy-ion collisions at intermediate energies

    Wen-Mei Guo🇨🇳 · Gao-Chan Yong🇨🇳 · Wei Zuo🇨🇳

    Based on the isospin-dependent Boltzmann-Uehling-Uhlenbeck(IBUU) transport model, effects of resonance potential on the free n/p and ratios in the central collision of at beam energies of 200 and 400 MeV/A are studied. It is found that the effect of potential on the ratio of pre-equilibrium free is invisible. The effect of isovector potential on the kinetic energy integrating ratio of may be observable only at lower incident beam energies and with stiffer symmetry energy. The strength of the isoscalar potential affects the height of the ratio around the Coulomb peak but does not affect the kinetic energy integrating ratio of . In heavy-ion collisions at intermediate energies, relating to the question of non-conservation of energy on or productions, one can replace the potential by nucleon isoscalar potential especially a soft symmetry energy is employed.

    Comments:
    5 pages, 9 figures, revised version, accepted by PRC
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    1509.04861 [pdf]
    PRC(2015)·17 citations
  4. 04

    [Submitted on 16 Sept 2015]

    Thermal shape fluctuation model study of the giant dipole resonance in Gd

    A. K. Rhine Kumar · P. Arumugam

    We have studied the giant dipole resonance (GDR) in the hot and rotating nucleus Gd within the framework of thermal shape fluctuation model (TSFM) built on the microscopic-macroscopic calculations of the free energies with a macroscopic approach for the GDR. Our results for GDR cross sections are in good agreement with the experimental values except for a component peaking around 17 MeV where the data has large uncertainties. Such a component is beyond our description which properly takes care of the splitting of GDR components due to the deformation and Coriolis effects. Around this 17 MeV lies the half maximum in experimental cross sections, and hence the extracted GDR widths and deformations (estimated from these widths) turn out to be overestimated and less reliable. Reproducing these widths with empirical formulae could conceal the information contained in the cross sections. Fully microscopic GDR calculations and a more careful look at the data could be useful to understand the GDR component around 17 MeV. We also discuss the occurrence of -softness in the free energy surfaces of Gd and its role on GDR.

    Comments:
    17 pages, 7 figures, Accepted for publication in Physical Review C
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1509.04986 [pdf]
    PRC(2015)·16 citations

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first authorsco-authorsvia INSPIRE