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Nuclear Theory·nucl-th

Friday·May 2, 2025

7 papers—4 primary·3 cross-listed

All7Primary4Cross-lists3
  1. 01

    [Submitted on 1 May 2025]

    Neutron Star Radii from Laboratory Experiments

    M. D. Cozma🇷🇴 · W. Trautmann🇩🇪

    Our present knowledge of the nuclear equation of state is briefly reviewed in this article intended for a wider readership. Particular emphasis is given to the asymmetric-matter equation of state required for modeling neutron stars, neutron-star mergers, and r-process nucleosynthesis. Recent analyses based on combining information obtained from nuclear theory, heavy-ion collisions and astrophysical observations confine the obtained radii of the canonical 1.4-solar-mass neutron star to values between 12 km and 13 km. The remaining uncertainty is primarily related to missing information in the density interval between nuclear saturation density and about twice that value which, however, is accessible with laboratory experiments.

    Comments:
    28 pages, 12 figures, invited review to appear in Int. J. Mod. Phys. E, v2 after minor corrections
    Subjects:
    Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Experiment (nucl-ex)
    arXiv:
    2505.00390 [pdf]
    IJMPE(2025)·4 citations
  2. 02

    [Submitted on 1 May 2025]

    Relativistic orbital-free kinetic energy density functional for one-particle nuclear systems

    X. H. Wu · Z. X. Ren · H. Z. Liang · P. W. Zhao

    This letter aims to derive the exact relativistic orbital-free kinetic energy density functional for one-particle nuclear systems in one-dimensional case. The kinetic energy is expressed as a functional of both vector and scalar densities. The functional derivatives of the kinetic energy density functional are also derived. Both the kinetic energy density functional and its functional derivatives are validated to be correct. This serves as a foundation for further exploration of more general relativistic orbital-free kinetic energy density functionals.

    Comments:
    6pages, 1figure
    Subjects:
    Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
    arXiv:
    2505.00397 [pdf]
    PRC(2025)·3 citations
  3. 03

    [Submitted on 1 May 2025]

    Unified QMF equation of state for neutron star matter: Static and dynamic properties

    Zhonghao Tu🇨🇳 · Xiangdong Sun🇨🇳 · Shuochong Han🇨🇳 · Zhiqiang Miao🇨🇳 · Ang Li🇨🇳

    We construct a set of unified equations of state based on the quark mean field (QMF) model, calibrated to different values of nuclear symmetry energy slope at the saturation density (), with the aim of exploring both the static properties and dynamical behavior of neutron stars (NSs), and building a coherent picture of their internal structure. We assess the performance of these QMF models in describing the mass-radius relation, the cooling evolution of isolated NSs and X-ray transients, and the instabilities (e.g., the r-mode). In comparison to relativistic mean field (RMF) models formulated at the hadronic level, the QMF model predicts heavier nuclear clusters and larger Wigner-Seitz cell sizes in the NS crust, while the density of the free neutron gas remains largely similar between the two approaches. For the cooling of isolated NSs, the thermal evolution is found to be insensitive to both the many-body model and the symmetry energy slope in the absence of the direct Urca (dUrca) process. However, when rapid cooling via the dUrca process is allowed, in the case of large values (e.g., MeV) in our study, the QMF model predicts a longer thermal relaxation time. Both the QMF and RMF models can reproduce cooling curves consistent with observations of X-ray transients (e.g., KS 1731--260) during their crustal cooling phase, although stellar parameters show slight variations depending on the model and symmetry energy slope. Within our unified framework, a larger value generally results in a wider instability window, while increasing the stellar mass tends to suppress the instability window. We also provide simple power-law parameterizations that quantify the dependence of bulk and shear viscosities on the symmetry energy slope for nuclear matter at saturation density.

    Comments:
    16 pages, 10 figures, 3 tables, version accepted for publication in Phys. Rev. D. (2025)
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
    arXiv:
    2505.00539 [pdf]
    PRD(2025)·3 citations
  4. 04

    [Submitted on 1 May 2025]

    Gluon Parts of Gravitational Form Factors and Mass Distribution

    Peter C. Tandy🇺🇸

    The parton structure of the nucleon and pion is investigated in an exploratory model that allows one to assess whether the dressing of quarks can, by itself, produce realistic gluon contributions to light-cone momentum fractions, gravitational form factors, mass/energy distributions and their radii. The model is the Dyson-Schwinger Equations in Rainbow-Ladder truncation. For the parton mass/energy distributions as a function of momentum transfer, we directly calculate matrix elements of the Energy-Momentum Tensor by utilizing its similarity to the momentum fraction moment of GPDs associated with deep inelastic scattering. A variety of gravitational form factors are obtained including the D-term.

    Comments:
    Contribution to International Conference QCHSC24, August 2024, Cairns, Australia; 11 pages, 3 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th)
    arXiv:
    2505.00583 [pdf]
    PoS(2025)·3 citations
  5. 05

    [Submitted on 30 Apr 2025] (cross-list from hep-ph)

    Quarkonia Theory: From Open Quantum System to Classical Transport

    Xiaojun Yao🇺🇸

    This is a theoretical overview of quarkonium production in relativistic heavy ion collisions given for the Hard Probes 2024 conference in Nagasaki. The talk focuses on the application of the open quantum system framework and the formulation of the chromoelectric correlator that uniquely encodes properties of the quark-gluon plasma relevant for quarkonium dynamics and thus can be extracted from theory-experiment comparison.

    Comments:
    8 pages, 2 figures, contribution to the proceedings of the 12th International Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collisions (Hard Probes 2024) in Nagasaki
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
    arXiv:
    2505.00098 [pdf]
    EPJ Web Conf.(2025)·2 citations
  6. 06

    [Submitted on 30 Apr 2025] (cross-list from astro-ph.HE)

    Enhanced Nuclear Binding Near the Proton Dripline Opens Possible Bypass of the rp-process Waiting Point

    Z. Meisel · W.-J. Ong · J.S. Randhawa

    We performed astrophysics model calculations with updated nuclear data to identify a possible bypass of the waiting-point, a defining feature of the rapid-proton capture (rp-) process that powers type-I x-ray bursts on accreting neutron stars. We find that the rp-process flow through the bypass could be up to 36\% for astrophysically relevant conditions. Our results call for new studies of , including the nuclear mass, -delayed proton emission branching, and nuclear structure as it pertains to the reaction rate at x-ray burst temperatures.

    Comments:
    Accepted to ApJ
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
    arXiv:
    2505.00143 [pdf]
    ApJ(2025)·1 citation
  7. 07

    [Submitted on 30 Apr 2025] (cross-list from astro-ph.HE)

    Bayesian Inference of Hybrid Star Properties from Future High-Precision Measurements of Their Radii

    Bao-An Li🇺🇸 · Xavier Grundler🇺🇸 · Wen-Jie Xie🇺🇸 · Nai-Bo Zhang🇺🇸

    Future high-precision X-ray and gravitational-wave observations of neutron stars (NSs) are expected to constrain NS radii with uncertainties as small as ~km. Such unprecedented precision offers a unique opportunity to extract new information about the nature and equation of state (EOS) of supradense matter in NS cores. Using mock radius data with uncertainties ranging from to ~km, together with a flexible meta-model NS EOS that allows for a first-order hadron-quark phase transition, we perform a Bayesian statistical analysis to assess the impact of radius measurements on EOS constraints. We find that high-precision radius measurements, particularly for massive NSs, significantly tighten constraints on the hadron-quark transition density , the quark matter mass fraction in NS cores, and several parameters characterizing the EOS of supranuclear hadronic matter, although the degree of improvement depends on the assumed prior range of . In contrast, even with the highest precision considered, NS radii -- including those of massive stars -- remain largely insensitive to the stiffness of quark matter, independent of the measurement accuracy or the prior range adopted for .

    Comments:
    Version accepted for publication by APJ
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2505.00194 [pdf]
    ApJ(2026)·16 citations

Affiliations

first authorsco-authorsvia INSPIRE