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Nuclear Theory·nucl-th

Friday·May 26, 2023

12 papers—3 primary·9 cross-listed

All12Primary3Cross-lists9
  1. 01

    [Submitted on 25 May 2023]

    Dineutron-dineutron correlation in He

    Y. Yamaguchi · W. Horiuchi · T. Ichikawa · N. Itagaki

    Background: The four-neutron correlation has been attracting much attention for decades. In addition to the study on the tetra-neutron system, it is worthwhile to investigate the correlation in bound systems. Purpose: The He nucleus is a system where four neutrons are weakly bound around the He core. The dineutron () correlation has been long discussed in various weakly-bound neutron-rich nuclei such as He and Li, whereas the He nucleus gives us an opportunity to investigate the - type four-neutron correlation. Methods: We introduce a microscopic model and describe the ground-state structure of He. The mixing of the two- component in the ground state is examined. The ground-state wave function is verified by investigating various observables including high-energy scattering cross sections. Results: Our model reasonably reproduces the available experimental data, the binding energy, charge radius, total reaction cross section, and proton-nucleus elastic scattering cross section data. We find that the significant mixing of the two- cluster configurations around He in the ground state of He: The ground state has a squared overlap of about 45% with a -He- configuration with the He- distance of 3 fm and opening angle of 80. Conclusion: The ground state of He contains a certain amount of the two- cluster component, indicating the strong nuclear deformation, which was experimentally observed recently.

    Comments:
    8 pages, 6 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2305.15624 [pdf]
    PRC(2023)·9 citations
  2. 02

    [Submitted on 25 May 2023]

    The Impact of Anisotropy on Neutron Star Properties: Insights from I-f-C Universal Relations

    Sailesh Ranjan Mohanty🇮🇳 · Sayantan Ghosh🇮🇳 · Pinku Routaray🇮🇳 · H. C. Das🇮🇳 · Bharat Kumar🇮🇳

    This study presents a universal relation for anisotropic neutron stars, called the relation, which accounts for the local anisotropic pressure using the Quasi-Local (QL) Model proposed by Horvat et al. \cite{QL_Model} to describe the anisotropy inside the neutron star. This study analyzes approximately 60 unified tabulated EoS-ensembles, spanning from relativistic to non-relativistic mean-field models, that comply with multimessenger constraints and cover a broad range of stiffness. The results indicate that the relationship between the parameters becomes more robust with positive anisotropy, while it weakens with negative anisotropy. With the help of the GW170817 \& GW190814 tidal deformability limit, a theoretical limit for the canonical -mode frequency for both isotropic and anisotropic stars is established. For isotropic case the canonical -mode frequency for event GW170817 \& GW190814 is and respectively. These established relationships have the potential to serve as a reliable tool to limit the equation of state of nuclear matter when measurements of relevant observables are obtained.

    Comments:
    Comments are welcome
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2305.15724 [pdf]
    JCAP(2024)·27 citations
  3. 03

    [Submitted on 25 May 2023]

    Equation of state of nuclear matter and neutron stars: Quark mean-field model versus relativistic mean-field model

    Zhenyu Zhu🇨🇳 · Ang Li🇨🇳 · Jinniu Hu🇨🇳 · Hong Shen🇨🇳

    The equation of state of neutron-rich nuclear matter is of interest to both nuclear physics and astrophysics. We have demonstrated the consistency between laboratory and astrophysical nuclear matter in neutron stars by considering low-density nuclear physics constraints (from Pb neutron-skin thickness) and high-density astrophysical constraints (from neutron star global properties). We have used both quark-level and hadron-level models, taking the quark mean-field (QMF) model and the relativistic mean-field (RMF) model as examples, respectively. We have constrained the equation of states of neutron stars and some key nuclear matter parameters within the Bayesian statistical approach, using the first multi-messenger event GW170817/AT 2017gfo, as well as the mass-radius simultaneous measurements of PSR J0030+0451 and PSR J0740+6620 from NICER, and the neutron-skin thickness of Pb from both PREX-II measurement and ab initio calculations. Our results show that, compared with the RMF model, QMF model's direct coupling of quarks with mesons and gluons leads to the evolution of the in-medium nucleon mass with the quark mass correction. This feature enables QMF model a wider range of model applicability, as shown by a slow drop of the nucleon mass with density and a large value at saturation that is jointly constrained by nuclear physics and astronomy.

    Comments:
    14 pages, 4 figures, 3 tables, Phys. Rev. C (2023) accepted
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2305.16058 [pdf]
    PRC(2023)·18 citations

Affiliations

first authorsco-authorsvia INSPIRE