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Nuclear Theory·nucl-th

Friday·June 19, 2026

9 papers—3 primary·6 cross-listed

All9Primary3Cross-lists6
  1. 01

    [Submitted on 18 Jun 2026]

    Parameter-free deformation variables of the proxy-SU(3) symmetry in even-even actinide, superheavy and hyperheavy nuclei with Z=82-126, N=82-258

    Dennis Bonatsos · V. K. B. Kota · Andriana Martinou · S. K. Peroulis · D. Petrellis · P. Vasileiou · T. J. Mertzimekis · N. Minkov

    Superheavy and hyperheavy nuclei are one of the frontiers of nuclear structure nowadays, while also for many actinides rather limited experimental information exists. Therefore, theoretical methods providing parameter-independent predictions for these nuclei are of particular interest. Such a method is the proxy-SU(3) approximation to the shell model, which has been adequately tested against experimental data in medium-mass and heavy nuclei up to the rare earth region, and has been found to provide reliable, parameter-independent predictions for the collective deformation variables beta and gamma. Within the proxy-SU(3) approach, the SU(3) symmetry of the 3-dimensional harmonic oscillator, which is destroyed beyond the sd shell by the strong spin-orbit interaction, is restored through a unitary transformation. For each nucleus, the most symmetric irreducible representation (irrep) allowed by the Pauli principle and the short-range nature of the nucleon-nucleon interaction, called the highest-weight (hw ) irrep in mathematical language, is found to suffice, except in cases in which the hw irrep turns out to be completely symmetric, so that the next highest weight (nhw) irrep has also to be included. In this article we provide a full collection of the hw and nhw irreps, as well as of the corresponding parameter-free predictions for the deformation variables beta and gamma, for all atomic nuclei ranging from Z=82, N=82 to Z=126, N=258. Several cases exemplifying the use of the collected results for studying the prolate to oblate shape transition, mirror symmetries, as well as the evolution of the collective variables along the valley of stability are also considered.

    Comments:
    36 pages, 3 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2606.19829 [pdf]
    Symmetry(2026)·0 citations
  2. 02

    [Submitted on 18 Jun 2026]

    Hybrid stars with hyperons: structure based on QCD sum rule coupling constants

    F. Moradi Jangal🇮🇷 · H. R. Moshfegh🇮🇷 · K. Azizi🇮🇷

    We present a comprehensive study of hybrid stars composed of hadrons, leptons, and quarks within a relativistic mean-field framework. Using coupling constants derived from QCD sum rules (QCDSR), we first determine the bulk properties of nuclear matter and evaluate the single-particle potentials of nucleons and hyperons to constrain the hadronic sector. The equation of state (EOS) under beta equilibrium is then constructed employing the model for the hadronic phase, while the quark phase is described using both the MIT bag model and the Nambu-Jona-Lasinio (NJL) model. The hadron-quark phase transition is analyzed through both Gibbs and Maxwell constructions. Based on resulting EOSs, we obtain the mass-radius relations of hybrid stars, investigate particle fractions and their radial distributions, and calculate the tidal Love number () and the dimensionless tidal deformability (). Our results provide quantitative predictions relevant for comparison with current multimessenger astrophysical observations.

    Comments:
    25 pages, 6 figures, 4 tables
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2606.20111 [pdf]
    0 citations
  3. 03

    [Submitted on 18 Jun 2026]

    Trace anomaly and interior curvature of neutron stars in energy-momentum squared gravity

    Ratikanta Swain🇮🇳 · Sayantan Ghosh🇮🇳 · Bharat Kumar🇮🇳

    In energy-momentum squared gravity (EMSG), the spacetime inside a neutron star is sourced by effective thermodynamic variables that need not coincide with the physical fluid pressure and energy density. It is therefore an open question whether the trace anomaly of dense matter -- the QCD measure of how strongly conformal symmetry is broken -- still organizes interior profiles and curvature in the same way it does in general relativity (GR). We adopt a clear matter-geometry separation: the trace anomaly is computed from the fluid sector alone, while spacetime curvature scalars are built from the variables that actually source the modified Tolman-Oppenheimer-Volkoff equations. For five relativistic mean-field equations of state, the radial trace-anomaly profiles increase monotonically from core to surface in all accepted EMSG models, as in GR, but split systematically with the EMSG coupling strength; the splitting grows with stellar compactness. Despite this deformation, curvature invariants still fall onto organized bands when plotted against the trace anomaly, extending the GR thermodynamic-geometric correspondence. The Ricci contraction shows the tightest organization, whereas the Ricci scalar remains the most equation-of-state sensitive. EMSG effects are modest for observationally accessible stars but largest in stiff, ultracompact configurations, indicating that the trace anomaly remains a useful thermodynamic label for interior geometry even when gravity couples nonlinearly to matter.

    Comments:
    Comments are welcome and appreciated
    Subjects:
    Nuclear Theory (nucl-th); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2606.20203 [pdf]
    1 citation

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