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Nuclear Theory·nucl-th

Monday·June 19, 2017

5 papers—4 primary·1 cross-listed

All5Primary4Cross-lists1
  1. 01

    [Submitted on 15 Jun 2017]

    Transport properties of isospin asymmetric nuclear matter using TDHF

    A.S. Umar · C. Simenel · W. Ye

    Background: The study of deep-inelastic reactions of nuclei provide a vehicle to investigate nuclear transport phenomena for a full range of equilibration dynamics. These inquires provide us the ingredients to model such phenomena and help answer important questions about the nuclear Equation of State (EOS) and its evolution as a function of neutron-to-proton ratio. Purpose: The motivation is to examine the real-time dynamics of nuclear transport phenomena and its dependence on asymmetry from a microscopic point of view to avoid any pre-conceived assumptions about the involved processes. Method: Time-dependent Hartree-Fock (TDHF) method in full 3D is employed to calculate deep-inelastic reactions of Kr+Pb and Kr+Pb systems at 8.5~MeV. The impact parameter and energy-loss dependence of relevant observables are calculated. In addition, density constrained TDHF method is used to compute excitation energies of the primary fragments. The statistical deexcitation code GEMINI is utilized to examine the final reaction products. Results: The kinetic energy loss and sticking times as a function of impact parameter are calculated. Final properties of the fragments (charge, mass, scattering angle, kinetic energy) are computed. Conclusions: We find a smooth dependence of the energy loss, , on the impact parameter for both systems. On the other hand the transfer properties for low values are very different for the two systems but become similar in the higher regime. The mean life time of the charge equilibration process, obtained from the final value of the fragments, is shown to be ~zs. This value is slightly larger (but of the same order) than the value obtained from reactions at Fermi energies.

    Comments:
    12 pages, 13 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1706.05024 [pdf]
    PRC(2017)·53 citations
  2. 02

    [Submitted on 16 Jun 2017]

    New results for the astrophysical S-factor and reaction rate of radiative 3He4He capture

    S. B. Dubovichenko · A. V. Dzhazairov-Kakhramanov · N.A. Burkova

    In the frame of modified potential cluster model based on the classification of orbital states by Young diagrams and revised interaction potential parameters for the bound states of 7Be in 3He4He cluster model with forbidden states the astrophysical S-factor for the radiative capture reaction has been calculated from the 10 keV. Obtained results S(23 keV) = 0.561 keV b reproduce the latest experimental data at 23 keV. Calculated and parametrized reaction rate is compared to some results known in the range of temperatures from 0.05 to 5 T9.

    Comments:
    7p., 4 fig., 1 tabl
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1706.05245 [pdf]
    Indian J.Phys.(2019)·6 citations
  3. 03

    [Submitted on 16 Jun 2017]

    In-medium bound states and pairing gap

    O.A. Rubtsova · V.I. Kukulin · V.N. Pomerantsev · H. Muether

    The propagator of two nucleons in infinite nuclear matter is evaluated by a diagonalization of the RPA Hamiltonian. This effective Hamiltonian is non-Hermitian and, for specific density domains and partial waves, yields pairs of complex conjugated eigenvalues representing in-medium bound states of two nucleons. The occurrence of these complex poles in the two-particle Greens function is tightly related to the well known BCS pairing approach. It is demonstrated that these complex eigenvalues and the corresponding bound state wavefunctions contain all information about the BCS gap function. This is illustrated by calculations for and pairing gaps in neutron matter which essentially coincide with the corresponding gap functions extracted from conventional solutions of the gap equation. Differences between the bound states in the conventional BCS approach and the RPA are arising in the case of channel in symmetric nuclear matter at low densities. These differences are discussed in the context of transition from BEC for quasi-deuterons to the formation of BCS pairing.

    Comments:
    7 pages, 7 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1706.05299 [pdf]
    PRC(2017)·12 citations
  4. 04

    [Submitted on 16 Jun 2017]

    Effect of intense magnetic fields on reduced-MHD evolution in = 200 GeV Au+Au collisions

    Victor Roy🇮🇳 · Shi Pu🇯🇵 · Luciano Rezzolla🇩🇪 · Dirk H. Rischke🇩🇪

    We investigate the effect of large magnetic fields on the dimensional reduced-magnetohydrodynamical expansion of hot and dense nuclear matter produced in = 200 GeV Au+Au collisions. For the sake of simplicity, we consider the case where the magnetic field points in the direction perpendicular to the reaction plane. We also consider this field to be external, with energy density parametrized as a two-dimensional Gaussian. The width of the Gaussian along the directions orthogonal to the beam axis varies with the centrality of the collision. The dependence of the magnetic field on proper time () for the case of zero electrical conductivity of the QGP is parametrized following [Deng 2012], and for finite electrical conductivity following [Tuchin 2013]. We solve the equations of motion of ideal hydrodynamics for such an external magnetic field. For collisions with non-zero impact parameter we observe considerable changes in the evolution of the momentum eccentricities of the fireball when comparing the case when the magnetic field decays in a conducting QGP medium and when no magnetic field is present. The elliptic-flow coefficient of is shown to increase in the presence of an external magnetic field and the increment in is found to depend on the evolution and the initial magnitude of the magnetic field.

    Comments:
    12 pages, 6 figures, new discussion added, published in Phys.Rev.C
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1706.05326 [pdf]
    PRC(2017)·83 citations

Affiliations

first authorsco-authorsvia INSPIRE