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Nuclear Theory·nucl-th

Wednesday·July 15, 2015

12 papers—4 primary·8 cross-listed

All12Primary4Cross-lists8
  1. 01

    [Submitted on 14 Jul 2015]

    Microscopic derivation of the quadrupole collective Hamiltonian for shape coexistence/mixing dynamics

    Kenichi Matsuyanagi · Masayuki Matsuo · Takashi Nakatsukasa · Kenichi Yoshida · Nobuo Hinohara · Koichi Sato

    Assuming that the time-evolution of the self-consistent mean field is determined by five pairs of collective coordinate and collective momentum, we microscopically derive the collective Hamiltonian for low-frequency quadrupole modes of excitation. We show that the five-dimensional collective Schrödinger equation is capable of describing large-amplitude quadrupole shape dynamics seen as shape coexistence/mixing phenomena. We focus on basic ideas and recent advances of the approaches based on the time-dependent mean-field theory, but relations to other time-independent approaches are also briefly discussed.

    Comments:
    24 pages, 4 figures. Contribution to the Focus Issue of Journal of Physics G on "Shape Coexistence in Atomic Nuclei" edited by John Wood and Kris Heyde
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1507.03709 [pdf]
    J.Phys.G(2016)·18 citations
  2. 02

    [Submitted on 14 Jul 2015]

    Relativistic Effects in 3-Nucleon Forces for Nuclear Matter and Finite Nuclei

    A.H. Lippok · H. Müther

    In order to simulate the relativistic effects of the Dirac Brueckner Hartree Fock approach for finite nuclei the part of the Urbana 3 nucleon (3N) force is considered, which represents the enhancement of the small components of the Dirac spinors for the nucleons in the nuclear medium. This 3N force is included in a Brueckner Hartree Fock calculation with rearrangement terms using a realistic model for the NN interaction. The strength of the 3N force is adjusted to reproduce the empirical saturation point of nuclear matter and then used in corresponding studies of the closed shell nuclei O and Ca. Special attention is paid to a consistent treatment of the spectrum of particle states in the NN propagator of the Bethe-Goldstone equation.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1507.03756 [pdf]
    PRC(2015)·6 citations
  3. 03

    [Submitted on 14 Jul 2015]

    Dirac Coupled Channel Analyses of Proton Inelastic Scattering from Ar Nucleus

    Sugie Shim

    0.8 GeV proton inelastic scatterings from Ar nucleus are analyzed using an optical potential model in the Dirac coupled channel formalism. A rotational collective model is used to obtain the transition optical potentials for the low lying excited states of the rotational band. The optical potential parameters of a Woods-Saxon shape and the deformation parameters of the excited states are searched phenomenologically to reproduce the experimental differential cross-section data by using the sequential iteration method. The effect of a multistep process is investigated by including the channel coupling between two excited states in addition to the couplings between the ground state and the excited states. The calculated deformation parameters of the excited states are compared with those obtained by using the nonrelativistic calculations. The results of the Dirac coupled channel calculations are found to show pretty good agreements with the experimental data of the ground state and the low-lying excited states. The multistep excitation process via the channel coupling with the second state is found to be important for the excitation of the state at the inelastic scatterings from the deformed nucleus, Ar.

    Comments:
    10 pages, 5 figures. arXiv admin note: substantial text overlap with arXiv:1501.00650
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1507.03774 [pdf]
    J.Korean Phys.Soc.(2015)·1 citation
  4. 04

    [Submitted on 14 Jul 2015]

    Collision Geometry and Flow in Uranium+Uranium Collisions

    Andy Goldschmidt🇺🇸 · Zhi Qiu🇺🇸 · Chun Shen🇨🇦 · Ulrich Heinz🇺🇸

    Using event-by-event viscous fluid dynamics to evolve fluctuating initial density profiles from the Monte-Carlo Glauber model for U+U collisions, we report a "knee"-like structure in the elliptic flow as a function of collision centrality, located around the 0.5% most central collisions as measured by the final charged multiplicity. This knee is due to the preferential selection of tip-on-tip collision geometries by a high-multiplicity trigger. Such a knee structure is not seen in the STAR data. This rules out the two-component MC-Glauber model for initial energy and entropy production. Hence an enrichment of tip-tip configurations by triggering solely on high-multiplicity in the U+U collisions does not work. On the other hand, by using the Zero Degree Calorimeters (ZDCs) coupled with event-shape engineering such a selection is possible. We identify the selection purity of body-body and tip-tip events in full-overlap U+U collisions. By additionally constraining the asymmetry of the ZDC signals we can further increase the probability of selecting tip-tip events in U+U collisions.

    Comments:
    7 pages, 5 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    1507.03910 [pdf]
    PRC(2015)·53 citations

Affiliations

first authorsco-authorsvia INSPIRE