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Nuclear Theory·nucl-th

Friday·September 5, 2025

10 papers—7 primary·3 cross-listed

All10Primary7Cross-lists3
  1. 08

    [Submitted on 3 Sept 2025] (cross-list from hep-ph)

    Strong CP Violation and large- spin-flavor symmetry

    Thomas R. Richardson🇺🇸

    We revisit the contribution of the QCD term to the CP violating pion-nucleon couplings and the nucleon electric dipole moment in a combined large- and chiral perturbation theory framework. In particular, we approach this issue through the emergent spin-flavor symmetry of the baryon sector at large but finite . We obtain good agreement with previous analyses for the pion-nucleon couplings and show that the large- framework indicates that tree-level contributions to the electric dipole moment possibly play a dominant role. The spin-flavor symmetry also enables us to provide novel constraints on CP violating pion- couplings as well as the electric dipole moment and transition moment.

    Comments:
    9 pages, version published in Phys. Rev. D
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
    arXiv:
    2509.03613 [pdf]
    PRD(2025)·3 citations
  2. 09

    [Submitted on 4 Sept 2025] (cross-list from astro-ph.HE)

    Stability analysis of two-fluid neutron stars featuring twin star and ultradense configurations

    Ankit Kumar🇯🇵 · Hajime Sotani🇯🇵

    We perform a detailed analysis of radial oscillations to discuss dynamical stability in two-fluid neutron stars composed of ordinary nuclear matter and a gravitationally coupled dark matter component. Using a fully relativistic two-fluid formalism, we solve the eigenvalue problem for a coupled system of equations with small-amplitude radial perturbations and derive the critical line corresponding to stability boundaries. We also compare these stability boundary lines obtained from the radial perturbations with those obtained from a generalized turning-point criterion based on extremization of mass and particle numbers, and find that the two methods agree to within better than across the parameter space explored. We consider both mirror dark matter and self-interacting fermionic dark matter models, and examine how microphysical propertiessuch as nuclear equations of state, dark matter mass, and vector coupling strengthreshape the topology of the stability boundary and gravitational mass contours. Our results reveal the emergence of ultra-dense and compact stars, with nuclear central densities exceeding single-fluid instability thresholds by factors of two or more, and the appearance of twin-star configurations with identical masses but distinct radii and internal fluid compositions. These findings have direct implications for the interpretation of neutron star observables and motivate future studies involving phase transitions, density discontinuities, or additional interactions in multi-component stellar systems. In particular, the emergence of exotic stable configurations beyond conventional stability limits underscores the need to reassess standard criteria in light of multi-fluid dynamics, with significant consequences for multimessenger probes of dense matterincluding gravitational wave signals, mass-radius constraints, and post-merger remnants.

    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    2509.03862 [pdf]
    PRD(2025)·10 citations
  3. 10

    [Submitted on 4 Sept 2025] (cross-list from hep-ph)

    Jet broadening and radiation in the early anisotropic plasma in heavy-ion collisions

    Alois Altenburger🇦🇹 · Kirill Boguslavski🇦🇹 · Florian Lindenbauer🇦🇹

    Measuring the energy loss of energetic jet partons may provide experimental opportunities to constrain the initial nonequilibrium stages in heavy-ion collisions, which requires theoretical predictions for the jet-medium potential. In this letter, we go beyond the usual harmonic approximation, extract this potential for the first time using QCD kinetic theory simulations, and provide a simple cutoff-independent small-distance form. We find significant differences to thermal media at early times in momentum and position space, as well as substantial angular dependence. Applying our results to the gluon splitting rates using a novel computational method reveals tensions in the current kinetic theory implementations for early times.

    Comments:
    5+7 pages, 3+3 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2509.03868 [pdf]
    14 citations

Affiliations

first authorsco-authorsvia INSPIRE