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Nuclear Theory·nucl-th

Tuesday·August 16, 2022

10 papers—6 primary·4 cross-listed

All10Primary6Cross-lists4
  1. 01

    [Submitted on 12 Aug 2022]

    Skyrme-Hartree-Fock-Bogoliubov mass models on a 3D mesh: II. Time-reversal symmetry breaking

    Wouter Ryssens🇧🇪 · Guillaume Scamps🇧🇪 · S. Goriely🇧🇪 · Michael Bender🇫🇷

    Models based on nuclear energy density functionals can provide access to a multitude of observables for thousands of nuclei in a single framework with microscopic foundations. Such models can rival the accuracy of more phenomenological approaches, but doing so requires adjusting parameters to thousands of nuclear masses. To keep such large-scale fits feasible, several symmetry restrictions are generally imposed on the nuclear configurations. One such example is time-reversal invariance, which is generally enforced via the Equal Filling Approximation (EFA). Here we lift this assumption, enabling us to access the spin and current densities in the ground states of odd-mass and odd-odd nuclei and which contribute to the total energy of such nuclei through so-called "time-odd" terms. We present here the Skyrme-based BSkG2 model whose parameters were adjusted to essentially all known nuclear masses without relying on the EFA, refining our earlier work [G. Scamps et al., EPJA 57, 333 (2021), arXiv:2011.07904]. Moving beyond ground state properties, we also incorporated information on the fission barriers of actinide nuclei in the parameter adjustment. The resulting model achieves a root-mean-square (rms) deviation of (i) 0.678 MeV on 2457 known masses, (ii) 0.027 fm on 884 measured charge radii, (iii) 0.44 MeV and 0.47 MeV, respectively, on 45 reference values for primary and secondary fission barriers of actinide nuclei, and (iv) 0.49 MeV on 28 fission isomer excitation energies. We limit ourselves here to a description of the model and the study the impact of lifting the EFA on ground state properties such as binding energies, deformation and pairing, deferring a detailed discussion of fission to a forthcoming paper.

    Comments:
    30 pages, 15 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2208.06455 [pdf]
    EPJA(2022)·43 citations
  2. 02

    [Submitted on 14 Aug 2022]

    There and Sharp Again: The Circle Journey of Nucleons and Energy Deposition

    Giuliano Giacalone🇩🇪

    A central question in high-energy nuclear phenomenology is how the geometry of the quark-gluon plasma (QGP) formed in relativistic nuclear collisions is precisely shaped. In our understanding of such processes, two features are especially crucial for the determination of the QGP geometry, respectively, the nucleon size and the energy deposition scheme. This contribution reports on the (circular) evolution of such features in state-of-the-art model incarnations of heavy-ion collisions over the past seven years. Ideas for future directions of investigation are pointed out.

    Comments:
    9 pages; 1 figure
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2208.06839 [pdf]
    14 citations
  3. 03

    [Submitted on 14 Aug 2022]

    Testing the collectivity in large and small colliding systems with test particles

    Han-Sheng Wang🇨🇳 · Guo-Liang Ma🇨🇳

    We propose a test-particle method to probe the transport dynamics of the establishment and development of collective flow in large and small systems of heavy-ion collisions. We place test particles as passengers into the partonic medium created by AuAu midcentral collisions at = 200 GeV and Pb central collisions at = 5.02 TeV, using a multiphase transport model. With the help of test particles in two extreme test cases, we demonstrate that parton collisions play an important role in establishing and developing collectivity in large and small colliding systems. The collectivity established by final state parton collisions is much stronger in large colliding systems compared to small colliding systems. The collectivity from the initial state can persist or survive more easily in small colliding systems than in large colliding systems due to fewer parton collisions. Our study provides a new method to understand the origin of collectivity in large and small colliding systems at the BNL Relativistic Heavy Ion Collider and the CERN Large Hadron Collider.

    Comments:
    11 pages, 17 figures, final published version
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2208.06854 [pdf]
    PRC(2022)·4 citations
  4. 04

    [Submitted on 15 Aug 2022]

    Relativistic correction to the dissociation temperature of B_c mesons in the hot medium

    Guangyu Li🇨🇳 · Baoyi Chen🇨🇳 · Yunpeng Liu🇨🇳

    By solving two body Dirac equations with potentials at finite temperature, we calculated the dissociation temperature T_d of B_c mesons in the quark-gluon plasma. It is found that the T_d becomes higher with the relativistic correction than the T_d from the Schroedinger equation. Both the short range interaction and the constant term of the potential at the long-range scale have a contribution to the shift of T_d, while the spin interaction is negligible.

    Comments:
    5 pages, 5 figures, accepted by Chinese Physics C
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2208.06986 [pdf]
    CPC(2023)·1 citation
  5. 05

    [Submitted on 15 Aug 2022]

    Unified description of high-energy nuclear collisions based on dynamical core--corona picture

    Yuuka Kanakubo🇯🇵

    I establish the dynamical core--corona initialization framework (DCCI2) as a state-of-the-art dynamical framework that is capable of describing small and large colliding systems at the LHC energies. Under the core--corona picture, contributions from both equilibrated (core) and non-equilibrated (corona) components are implemented. I describe the dynamical separation of the system into the core and corona at the initial stage by incorporating the core--corona picture into the novel dynamical initialization framework. With DCCI2, I simulate + collisions at TeV and + collisions at TeV. Especially, I extract the fractions of core and corona components in final hadron yields in + and + collisions as functions of multiplicity, and reveal that the core components become dominant at . I also find that the corona contribution at very low (below GeV) is non-negligible even in + collisions and show that such contributions significantly affect -integrated flow coefficients. These results strongly suggest the importance of considering non-equilibrated components to extract transport coefficients of quark-gluon plasma from model-to-data comparisons quantitatively.

    Comments:
    183 pages, Ph.D. thesis, overlap with arXiv:2207.13966 and arXiv:2108.07943
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2208.07029 [pdf]
    2 citations
  6. 06

    [Submitted on 15 Aug 2022]

    A Semi-analytical Method of Calculating Nuclear Collision Trajectory in the QCD Phase Diagram

    Zi-Wei Lin🇺🇸 · Todd Mendenhall🇺🇸

    The finite nuclear thickness affects the energy density and conserved-charge densities such as the net-baryon density produced in heavy ion collisions. While the effect is small at high collision energies where the Bjorken energy density formula for the initial state is valid, the effect is large at low collision energies, where the nuclear crossing time is not small compared to the parton formation time. The temperature and chemical potentials of the dense matter can be extracted from the densities for a given equation of state (EOS). Therefore, including the nuclear thickness is essential for the determination of the - trajectory in the QCD phase diagram for relativistic nuclear collisions at low to moderate energies such as the RHIC-BES energies. In this proceeding, we will first discuss our semi-analytical method that includes the nuclear thickness effect and its results on the densities , and . Then, we will show the extracted , and for a quark-gluon plasma using the ideal gas EOS with quantum or Boltzmann statistics. Finally, we will show the results on the - trajectories in relation to the possible location of the QCD critical end point. This semi-analytical model provides a convenient tool for exploring the trajectories of nuclear collisions in the QCD phase diagram.

    Comments:
    7 pages, 5 figures, proceedings for the 37th Winter Workshop on Nuclear Dynamics
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2208.07203 [pdf]
    Rev.Mex.Fis.Suppl.(2022)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE