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Nuclear Theory·nucl-th

Tuesday·December 6, 2022

12 papers—6 primary·6 cross-listed

All12Primary6Cross-lists6
  1. 01

    [Submitted on 5 Dec 2022]

    A Kohn-Sham Scheme Based Neural Network for Nuclear Systems

    Zu-Xing Yang · Xiao-Hua Fan · Zhi-Pan Li · Haozhao Liang

    A Kohn-Sham scheme based multi-task neural network is elaborated for the supervised learning of nuclear shell evolution. The training set is composed of the single-particle wave functions and occupation probabilities of 320 nuclei, calculated by the Skyrme density functional theory. It is found that the deduced density distributions, momentum distributions, and charge radii are in good agreements with the benchmarking results for the untrained nuclei. In particular, accomplishing shell evolution leads to a remarkable improvement in the extrapolation of nuclear density. After a further charge-radius-based calibration, the network evolves a stronger predictive capability. This opens the possibility to infer correlations among observables by combining experimental data for nuclear complex systems.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2212.02093 [pdf]
    PLB(2023)·14 citations
  2. 02

    [Submitted on 5 Dec 2022]

    Charge-dependent anisotropic flow in high-energy heavy-ion collisions from relativistic resistive magneto-hydrodynamic expansion

    Kouki Nakamura🇯🇵 · Takahiro Miyoshi🇯🇵 · Chiho Nonaka🇯🇵 · Hiroyuki R. Takahashi🇯🇵

    We have investigated the charge-dependent anisotropic flow in high-energy heavy-ion collisions, using relativistic resistive magneto-hydrodynamics (RRMHD). We consider the optical Glauber model as an initial model of the quark-gluon plasma (QGP) and the solution of the Maxwell equations with source term of the charged particles in two colliding nuclei as initial electromagnetic fields. The RRMHD simulation is performed with these initial conditions in Au-Au and Cu-Au collisions at GeV. We have calculated the charge-odd contribution to the directed flow and elliptic flow in both collisions based on electric charge distributions as a consequence of RRMHD. Our results show that the and are approximately proportional to the electrical conductivity () of the medium. In the case, our result of is consistent with STAR data in Au-Au collisions. Furthermore, in Cu-Au collisions, has a non-zero value at . We conclude that the charge-dependent anisotropic flow is a good probe to extract the electrical conductivity of the QGP medium in high-energy heavy-ion experiments.

    Comments:
    10 pages, 9 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2212.02124 [pdf]
    PRC(2023)·17 citations
  3. 03

    [Submitted on 5 Dec 2022]

    Progress in Nuclear Astrophysics: a multi-disciplinary field with still many open questions

    S. Goriely · A. Choplin · W. Ryssens · I. Kullmann

    Nuclear astrophysics is a multi-disciplinary field with a huge demand for nuclear data. Among its various fields, stellar evolution and nucleosynthesis are clearly the most closely related to nuclear physics. The need for nuclear data for astrophysics applications challenges experimental techniques as well as the robustness and predictive power of present nuclear models. Despite impressive progress for the last years, major problems and puzzles remain. In the present contribution, only a few nuclear astrophysics specific aspects are discussed. These concern some experimental progress related to the measurement of key reactions of relevance for the so-called s-and p-processes of nucleosynthesis, the theoretical effort in predicting nuclear properties of exotic neutron-rich nuclei of interest for the r-process nucleosynthesis, and the recent introduction of machine learning techniques in nuclear astrophysics applications.

    Comments:
    8 pages, 4 figures; Contribution to the proceedings of INPC 2022, Cape Town, South Africa
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Experiment (nucl-ex)
    arXiv:
    2212.02156 [pdf]
    J.Phys.Conf.Ser.(2023)·1 citation
  4. 04

    [Submitted on 5 Dec 2022]

    Influence of hyperon-hyperon interaction on the properties of neutron stars

    R. M. Aguirre🇦🇷

    The properties of neutron stars are studied in a composite model of the strong interaction. In the regime of low to medium baryonic densities a covariant hadronic model is adopted which includes an exclusive channel for the hyperon-hyperon interaction mediated by hidden strangeness mesons, which in turn couple to other mesons through polynomial vertices. The new coupling constants are subject to phenomenological constraints. The presence of free quarks in the core of the star is considered by using the Nambu-Jona Lasinio model supplemented with a vector interaction. The deconfinement process is described by a continuous coexistence of phases. Several structure parameters of neutron stars, such as mass-radius relation, moment of inertia, tidal deformability, and the propagation of nonradial f and g-modes within the relativistic Cowling approximation are studied. The predictions of the model are in good agreement with recent observational data, in particular the maximum inertial mass is greater than the observational lower limit of two solar masses.

    Comments:
    Accepted for publication in Journal of Physics G. The present version matches the accepted for publication manuscript. The title has been changed. This Accepted Manuscript is available for reuse under a CC BY-NC-ND licence after the 12 month embargo period provided that all the terms and conditions of the licence are adhered to
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2212.02273 [pdf]
    J.Phys.G(2024)·2 citations
  5. 05

    [Submitted on 5 Dec 2022]

    Complex eigenenergy of GDR for O by the Jost function within RPA framework

    K. Mizuyama · N. Nhu Le · T. V. Nhan Hao · N. Hoang Tung · T. Dieu Thuy

    The Jost function method is extended within the framework of the RPA theory to find poles on the complex energy plane that exhibit complex RPA eigenenergies. Poles corresponding to the RPA excited states such as the giant resonance of O electric dipole excitations were successfully found on the complex energy plane. Although the giant resonance has been known as a single resonance with large strength and width, it is found that, at least within the RPA framework, the O electric dipole giant resonance is formed by multiple poles, each of which is an independent pole with different widths, origins, response properties to residual interactions, and components structures of the density fluctuation.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2212.02276 [pdf]
    PRC(2023)·4 citations
  6. 06

    [Submitted on 5 Dec 2022]

    Metric anisotropies and nonequilibrium attractor for expanding plasma

    Nisarg Vyas🇮🇳 · Sunil Jaiswal🇮🇳 · Amaresh Jaiswal🇮🇳

    We consider the evolution of a system of chargeless and massless particles in an anisotropic space-time given by the Bianchi type I metric. Specializing to the axis-symmetric case, we derive the framework of anisotropic hydrodynamics from the Boltzmann equation in the relaxation-time approximation. We consider the case of the axis-symmetric Kasner metric and study the approach to the emergent attractor in near and far-off-equilibrium regimes. Further, by relaxing the Kasner conditions on metric coefficients, we study the effect of expansion geometries on the far-off-equilibrium attractor and discuss its implications in the context of relativistic heavy-ion collisions.

    Comments:
    9 pages, 6 figures. Published version
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th)
    arXiv:
    2212.02451 [pdf]
    PLB(2023)·6 citations

Affiliations

first authorsco-authorsvia INSPIRE