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Nuclear Theory·nucl-th

Thursday·December 8, 2016

11 papers—5 primary·6 cross-listed

All11Primary5Cross-lists6
  1. 01

    [Submitted on 7 Dec 2016]

    Cluster states in stable and unstable nuclei

    M. Kimura🇯🇵

    In this contribution, I will discuss two topics related to the clustering of atomic nuclei. The first is dual character of the ground state. Recently, it was pointed out that the ground states of atomic nuclei have dual character of shell and cluster implying that both of the single-particle excitation and cluster excitation occur as the fundamental excitation modes. The isoscalar monopole and dipole transitions are regarded as the triggers to induce the cluster excitation. By referring the Hartree-Fock and antisymmetrized molecular dynamics calculations, the dual character and those transitions are explained. The second is the linear-chain state of in which the linearly aligned 3 particles are sustained by the valence neutrons. The rather convincing evidences for this exotic state are very recently reported by several experiments. Here, I introduce a couple of theoretical analysis and predictions.

    Comments:
    23 pages, to be published in the ebook "Progress of time-dependent nuclear reaction theory" (Betham Science Publishers 2016) honoring Prof. Joachim Maruhn's retirement
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    1612.02086 [pdf]
    2 citations
  2. 02

    [Submitted on 7 Dec 2016]

    Internal Charmonium Evolution in the Quark-Gluon Plasma

    Baoyi Chen · Xiaojian Du🇺🇸 · Ralf Rapp🇺🇸

    We employ a time-dependent Schrödinger equation to study the evolution of a dipole in a quark-gluon plasma (QGP). Medium effects on the heavy-quark potential in the QGP are found to significantly affect the timescales of the internal evolution of the dipole. Color-screening can enhance the overlap of the expanding wavepackage with excited states at high temperature, while it is reduced at lower temperatures where the dipole favors the formation of the charmonium ground state. We investigate the consequences of this mechanism on the double ratio of charmonium nuclear modification factors, , in heavy-ion collisions. The impact of the transition mechanisms on this ratio turns out to be rather sensitive to the attractive strength of the potential, and to its temperature dependence.

    Comments:
    4 pages, 4 figures, proceeding for Hard Probe 2016
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1612.02089 [pdf]
    Nucl.Part.Phys.Proc.(2017)·6 citations
  3. 03

    [Submitted on 7 Dec 2016]

    Fission barriers of two odd-neutron actinide nuclei taking into account the time-reversal symmetry breaking at the mean-field level

    Meng-Hock Koh🇫🇷 · L. Bonneau🇫🇷 · P. Quentin🇫🇷 · T. V. Nhan Hao🇺🇸 · Wagiran Husin🇲🇾

    Background: Fission barriers of actinide nuclei have been mostly and for long been microscopi- cally calculated for even-even fissioning systems. Calculations in the case of odd nuclei have been performed merely within a so-called equal-filling approximation (EFA) as opposed to an approach taking explicitly into account the time reversal breaking properties at the mean field level- and for only one single-particle configuration. Purpose: We study the dependence of the fission barriers on various relevant configurations (e.g. to evaluate the so-called specialization energy). Besides, we want to assess the relevance as a func- tion of the deformation of the EFA approach which has been already found out at ground state deformation. Methods: Calculations within the Hartree-Fock plus BCS with self-consistent particle blocking have been performed using the SkM* Skyrme effective interaction in the particle-hole channel and a seniority force in the particle-particle channel. Axial symmetry has been imposed throughout the whole fission path while the intrinsic parity symmetry has been allowed to be broken in the outer fission barrier region. Results: Potential energy curves have been determined for six different configurations in U-235 and four in Pu-239. Inner and outer fission barriers have been calculated along with some spectroscopic properties in the fission isomeric well. These results have been compared with available data. The influence of time-reversal breaking mean fields on the solutions has been investigated. Conclusions: A sizeable configuration dependence of the fission barrier (width and height) has been demonstrated. A reasonable agreement with available systematic evaluations of fission barrier heights has been found. The EFA approach has been validated at the large elongations occurring at the outer barrier region.

    Comments:
    25 pages, 11 figures, accepted for publication in PRC
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1612.02118 [pdf]
    PRC(2017)·11 citations
  4. 04

    [Submitted on 7 Dec 2016]

    Microscopic Study of Superfluidity in Dilute Neutron Matter

    G. E. Pavlou · E. Mavrommatis · Ch. Moustakidis · J. W. Clark

    Singlet -wave superfluidity of dilute neutron matter is studied within the correlated BCS method, which takes into account both pairing and short-range correlations. First, the equation of state (EOS) of normal neutron matter is calculated within the Correlated Basis Function (CBF) method in lowest cluster order using the and components of the Argonne potential, assuming trial Jastrow-type correlation functions. The superfluid gap is then calculated with the corresponding component of the Argonne potential and the optimally determined correlation functions. The dependence of our results on the chosen forms for the correlation functions is studied, and the role of the -wave channel is investigated. Where comparison is meaningful, the values obtained for the gap within this simplified scheme are consistent with the results of similar and more elaborate microscopic methods.

    Comments:
    9 pages, 6 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Quantum Gases (cond-mat.quant-gas); Superconductivity (cond-mat.supr-con)
    arXiv:
    1612.02188 [pdf]
    EPJA(2017)·14 citations
  5. 05

    [Submitted on 7 Dec 2016]

    Study of chiral vortical and magnetic effects in the anomalous transport model

    Yifeng Sun🇺🇸 · Che Ming Ko🇺🇸

    We extend our recent study of chiral magnetic effect in relativistic heavy ion collisions based on an anomalous transport model by including also the chiral vortical effect. We find that although vorticities in the chirally restored quark matter, which result from the large angular momentum in non-central collisions, can generate an axial charge dipole moment in the transverse plane of a heavy ion collision, it does not produce a difference in the eccentricities of negatively and positively charged particles. As a result, including the chiral vortical effect alone cannot lead to a splitting between the elliptic flows of negatively and positively charged particles. On the other hand, negatively and positively charged particles do develop a splitting in their elliptic flows if the effect due to a strong and long-lived magnetic field is also included. However, to have a positive slope in the dependence of the elliptic flow splitting on the charge asymmetry of the quark matter, as seen in experiments, requires the neglect of the effect of the Lorentz force. In this case, an elliptic flow splitting appears even at vanishing charge asymmetry.

    Comments:
    7 pages, 7 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1612.02408 [pdf]
    PRC(2017)·32 citations

Affiliations

first authorsco-authorsvia INSPIRE