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Nuclear Theory·nucl-th

Friday·July 24, 2020

6 papers—5 primary·1 cross-listed

All6Primary5Cross-lists1
  1. 01

    [Submitted on 23 Jul 2020]

    Parameterizing Smooth Viscous Fluid Dynamics With a Viscous Blast Wave

    Zhidong Yang🇺🇸 · Rainer J. Fries🇺🇸

    Blast wave fits are widely used in high energy nuclear collisions to capture essential features of global properties of systems near kinetic equilibrium. They usually provide temperature fields and collective velocity fields on a given hypersurface. We systematically compare blast wave fits of fluid dynamic simulations for Au+Au collisions at GeV and Pb+Pb collisions at TeV with the original simulations. In particular, we investigate how faithful the viscous blast wave introduced in \cite{Yang:2022yxa} can reproduce the given temperature and specific shear viscosity fixed at freeze-out of a viscous fluid dynamic calculation, if the final spectrum and elliptic flow of several particle species are fitted. We find that viscous blast wave fits describe fluid dynamic pseudodata rather well and reproduce the specific shear viscosities to good accuracy. However, extracted temperatures tend to be underpredicted, especially for peripheral collisions. We investigate possible reasons for these deviations. We establish maps from true to fitted values. These maps can be used to improve raw fit results from viscous blast wave fits. Although our work is limited to two specific, albeit important, parameters and two collision systems, the same procedure can be easily generalized to other parameters and collision systems.

    Comments:
    14 pages, 7 figures; v2: a few references added; v3: major update to strengthen conclusions and reduce overlap with 1807.03410, figures 4-10 added or updated
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2007.11777 [pdf]
    J.Phys.G(2024)·13 citations
  2. 02

    [Submitted on 23 Jul 2020]

    Temperature evolution of the nuclear shell structure and the dynamical nucleon effective mass

    Herlik Wibowo🇺🇸 · Elena Litvinova🇺🇸 · Yinu Zhang🇺🇸 · Paolo Finelli🇮🇹

    We study the fermionic Matsubara Green functions in medium-mass nuclei at finite temperature. The single-fermion Dyson equation with the dynamical kernel of the particle-vibration-coupling (PVC) origin is formulated and solved in the basis of Dirac spinors, which minimize the grand canonical potential with the meson-nucleon covariant energy density functional. The PVC correlations beyond mean field are taken into account in the leading approximation for the energy-dependent self-energy, and the full solution of the finite-temperature Dyson equation is obtained for the fermionic propagators. Within this approach, we investigate the fragmentation of the single-particle states and its evolution with temperature for the nuclear systems Ni and Fe relevant for the core-collapse supernova. The energy-dependent, or dynamical, nucleon effective mass is extracted from the PVC self-energy at various temperatures.

    Comments:
    Article: 10 pages, 11 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2007.11793 [pdf]
    PRC(2020)·4 citations
  3. 03

    [Submitted on 23 Jul 2020]

    Coupled-cluster computations of optical potential for medium-mass nuclei

    J. Rotureau

    Recent progress in the numerical solution of the nuclear many-body problem and in the development of nuclear Hamiltonians rooted in Quantum Chromodynamics, has opened the door to first-principle computations of nuclear reactions. In this article, we discuss the current status of ab initio calculations of nucleon-nucleus optical potentials for medium-mass systems, with a focus on results obtained with the coupled-cluster method.

    Comments:
    17 pages, 4 figures, to be published in Frontiers in Physics as a contribution to the Research Topic "The Future of Nuclear Structure: Challenges and Opportunities in the Microscopic Description of Nuclei"
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2007.11913 [pdf]
    Front.in Phys.(2020)·12 citations
  4. 04

    [Submitted on 23 Jul 2020]

    Constraining the in-medium nucleon-nucleon cross section from the width of nuclear giant dipole resonance

    Rui Wang · Zhen Zhang · Lie-Wen Chen · Che Ming Ko · Yu-Gang Ma

    We develop a new lattice Hamiltonian method for solving the Boltzmann-Uehling-Uhlenbeck (BUU) equation. Adopting the stochastic approach to treat the collision term and using the GPU parallel computing to carry out the calculations allows for a rather high accuracy in evaluating the collision term, especially its Pauli blocking, leading thus to a new level of precision in solving the BUU equation. Applying this lattice BUU method to study the width of giant dipole resonance (GDR) in nuclei, where the accurate treatment of the collision term is crucial, we find that the obtained GDR width of shows a strong dependence on the in-medium nucleon-nucleon cross section . A very large medium reduction of is needed to reproduce the measured value of the GDR width of at the Research Center for Nuclear Physics in Osaka, Japan.

    Comments:
    7 pages, 3 figures. Accepted for publication in Physics Letters B
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2007.12011 [pdf]
    PLB(2020)·31 citations
  5. 05

    [Submitted on 23 Jul 2020]

    Complex scaling : physics of unbound light nuclei and perspective

    Takayuki Myo · Kiyoshi Kato

    The complex scaling method (CSM) is one of the most powerful methods of describing the resonances with complex energy eigenstates, based on non-Hermitian quantum mechanics. We present the basic application of CSM to the properties of the unbound phenomena of light nuclei. In particular, we focus on many-body resonant and non-resonant continuum states observed in unstable nuclei. We also investigate the continuum level density (CLD) in the scattering problem in terms of the Green's function with CSM. We discuss the explicit effects of resonant and non-resonant contributions in CLD and transition strength functions.

    Comments:
    38 pages, 33 figures, to be published in Progress of Theoretical and Experimental Physics
    Subjects:
    Nuclear Theory (nucl-th); Atomic Physics (physics.atom-ph)
    arXiv:
    2007.12172 [pdf]
    PTEP(2020)·56 citations
  6. 06

    [Submitted on 23 Jul 2020] (cross-list from hep-ph)

    Reggeon Field Theory and Self Duality: Making Ends Meet

    Alex Kovner🇺🇸 · Eugene Levin🇨🇱 · Ming Li🇺🇸 · Michael Lublinsky🇮🇱

    Motivated by the question of unitarity of Reggeon Field Theory, we use the effective field theory philosophy to find possible Reggeon Field Theory Hamiltonians . We require that is self dual, reproduce all known limits (dilute-dense and dilute-dilute) and exhibits all the symmetries of the JIMWLK Hamiltonian. We find a family of Hamiltonians which satisfy all the above requirements. One of these is identical in form to the so called "diamond action" discussed in \cite{diamond,Balitsky05}. However we show by explicit calculation that the so called "diamond condition" is not satisfied beyond leading perturbative order.

    Comments:
    42 pages, 7 figures; revised version responding to referee report
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2007.12132 [pdf]
    JHEP(2020)·15 citations

Affiliations

first authorsco-authorsvia INSPIRE