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Nuclear Theory·nucl-th

Tuesday·July 21, 2026

14 papers—11 primary·3 cross-listed

All14Primary11Cross-lists3
  1. 12

    [Submitted on 17 Jul 2026] (cross-list from hep-ph)

    Transverse Charge Distribution as a Probe of Nucleon Transversity

    Wanchen Li🇨🇳 · Xiaohui Liu🇨🇳 · Ding Yu Shao🇨🇳

    We introduce the transverse charge distribution as a spin-sensitive charge-flow probe for fragmentation and nucleon tomography. By measuring the angular distribution of net electric charge around a fragmenting quark, this observable relies entirely on the tracking of charged-particle directions and charge signs, strictly bypassing the need for calorimetric energy measurements. At leading twist, the distribution decomposes into an unpolarized charge monopole and a chiral-odd transverse charge dipole. We derive the operator product expansion of these distributions onto charge-weighted collinear moments: a charge monopole and a charge dipole governed by the Collins effect and couples directly to transversity. Applying this formalism to transversely polarized collisions at RHIC, we show that charge weighting suppresses the unpolarized monopole background and causes the spin-dependent dipoles from oppositely charged hadrons to add coherently. This coherence strongly enhances the resulting azimuthal asymmetries, establishing a theoretically clean and experimentally precise track-only avenue for extracting transversity.

    Comments:
    7 pages, 4 figures + Supplemental Material (5 pages, 1 figure)
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2607.16392 [pdf]
    1 citation
  2. 13

    [Submitted on 17 Jul 2026] (cross-list from hep-ph)

    Attractodynamics in 0+1D

    Jean F. Du Plessis🇺🇸 · Bruno Scheihing-Hitschfeld🇺🇸 · Rachel Steinhorst🇺🇸

    Hydrodynamics is a macroscopic theory of long-wavelength dynamics around local thermal equilibrium. We develop attractodynamics, the analogous construction around a far-from-equilibrium attractor. Dynamics near a far-from-equilibrium attractor retains some non-hydrodynamic microscopic information, which attractodynamics systematically organizes. We move towards this general structure by starting in 0+1D, and consider a model for which an anisotropic far-from-equilibrium attractor solution is exactly known. This setting provides a clean benchmark in which the ideal attractodynamic equations and a leading transient residual extension can be compared directly with the full kinetic evolution. The resulting hierarchy gives an improvable description of near-attractor dynamics: the ideal theory captures evolution close to the attracting manifold, while retaining the leading off-attractor moments extends the regime of agreement until the finite truncation breaks down. This example identifies the ingredients needed for local 3+1D attractodynamics and for macroscopic attractodynamic theories not derived from an underlying kinetic description.

    Comments:
    34 pages, 12 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    2607.16393 [pdf]
    0 citations
  3. 14

    [Submitted on 20 Jul 2026] (cross-list from astro-ph.HE)

    Quantifying the Information Gain from Future High-Precision Radius Measurements for Identifying Twin Neutron Stars

    Bao-An Li🇺🇸 · Xavier Grundler🇺🇸

    Twin neutron stars (NSs), characterized by identical gravitational masses but different radii, are among the most promising astrophysical signatures of a strong first-order hadron--quark phase transition in supradense matter. We investigate how increasingly precise NS radius measurements improve the Bayesian inference of twin-star observability using mock radius data for a canonical NS. Radius uncertainties are varied from the current level of about km to the km precision anticipated from future X-ray and gravitational-wave observations. We quantify the information gained using the posterior distribution of the maximum twin-star radius separation together with an analytical model of branch distinguishability and complementary information-theoretic measures based on the branch observational efficiency and the Shannon entropy. The combined analyses reveal three inference regimes: a prior-dominated regime for km, a rapid information-gain regime for km, and an information-saturation regime for km. These complementary analyses consistently indicate that radius measurements with a precision of about km already extract most of the information available for identifying twin NSs within the present Bayesian framework. Beyond establishing a quantitative observational benchmark for future high-precision radius measurements, this work provides a general Bayesian framework for quantifying the information gain from progressively more precise observations and identifying the point of diminishing scientific returns.

    Comments:
    Version accepted by Phys. Lett. B
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2607.18124 [pdf]
    PLB(2026)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE