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Nuclear Theory·nucl-th

Friday·May 2, 2025

7 papers—4 primary·3 cross-listed

All7Primary4Cross-lists3
  1. 01

    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.

    nucl-thastro-ph.SRnucl-exIJMPE(2025)·4 citations
  2. 02

    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.

    nucl-thquant-phPRC(2025)·3 citations
  3. 03

    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.

    nucl-thastro-ph.HEPRD(2025)·3 citations
  4. 04

    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.

    nucl-thhep-phhep-thPoS(2025)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE