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Nuclear Theory·nucl-th

Thursday·April 9, 2026

10 papers—3 primary·7 cross-listed

All10Primary3Cross-lists7
  1. 04

    [Submitted on 7 Apr 2026] (cross-list from astro-ph.HE)

    Anisotropic hybrid stars: Interplay of superconductivity and magnetic field leading to gravitational waves

    Zenia Zuraiq🇮🇳 · Banibrata Mukhopadhyay🇮🇳

    Neutron stars, at their cores, are highly dense and, thus, are expected to have a number of exotic processes. This includes a possible phase transition to deconfined quark matter at the core, leading to a hybrid star. The quark matter is expected to additionally be color superconducting. The physics of superconductivity plays an important role in understanding the high density matter in the interiors of neutron/hybrid stars. At their high densities, additionally, both proton superconductivity and neutron superfluidity are expected. We study the effect of superconducting (quark/proton) matter, along with the internal magnetic field, leading to pressure anisotropy within hybrid stars. We aim to probe the effect of superconductivity, especially from color superconducting quarks, in hybrid star structure. We propose new phenomenological model anisotropy profiles within a one-dimensional framework. We model quark matter using the vector interaction enhanced Bag model, and hadron matter with the DD2 equation of state. A Maxwell construction joins both phases. We further investigate the possible observational signatures of these hybrid stars. These include mass enhancement and continuous gravitational waves, possibly arising from the anisotropy induced deformation, helping us further constrain our model and its physical parameters.

    Comments:
    15 pages, 8 figures (16 pdf files), 4 tables
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
    arXiv:
    2604.06308 [pdf]
    1 citation
  2. 05

    [Submitted on 7 Apr 2026] (cross-list from hep-ph)

    Distribution amplitudes and functions of ground-state scalar and pseudoscalar charmonia

    X.-Y. Zeng🇨🇳 · Y.-Y. Xiao🇨🇳 · Z.-N. Xu🇨🇳 · C. D. Roberts🇨🇳 · J. Rodríguez-Quintero🇨🇳

    Charmonia are often supposed to provide simple hydrogen-like ``atomic'' systems that can be used to obtain insights into heavier-quark QCD. We use continuum Schwinger function methods to analyse this hypothesis in connection with ground-state scalar and pseudoscalar charmonia and find that a more complex picture of these states may be necessary. For instance, considering orbital angular momentum, the is not a simple -wave system; similarly, the wave function contains more than merely -wave contributions. The distribution amplitudes (DAs) and distribution functions (DFs) of these mesons are also nontrivial. For instance, the DA is not positive definite: owing to QCD symmetries, it possesses domains of balanced negative and positive support. This feature is also expressed in the DF, but differences between and DFs diminish under scale evolution. Notably, the light-front momentum fraction carried by glue is the same in both states: it is 10\% less than the in-pion glue momentum fraction. Whilst experimental confirmation of the predictions herein is unlikely, our results should serve as benchmarks for complementary theory attempts to understand local and global structural features of heavier-quark hadrons.

    Comments:
    9 pages, 5 figures, 6 tables
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2604.06510 [pdf]
    1 citation
  3. 06

    [Submitted on 8 Apr 2026] (cross-list from hep-lat)

    Quantum simulation of baryon scattering in SU(2) lattice gauge theory

    João Barata🇨🇭 · Juan Hormaza🇨🇴 · Zhong-Bo Kang🇺🇸 · Wenyang Qian🇨🇳

    We present a first real-time study of hadronic scattering in a -dimensional SU(2) lattice gauge theory with fundamental fermions using tensor-network techniques. Working in the gaugeless Hamiltonian formulation, we investigate scattering processes across sectors of fixed global baryon number , corresponding respectively to meson--meson, meson--baryon, and baryon--baryon collisions. At strong coupling, the and channels exhibit predominantly elastic dynamics closely resembling the U(1) Schwinger model. The mixed sector displays qualitatively new behavior: meson and baryon wavepackets become entangled during the collision, with the slower state becoming spatially delocalized while the faster one propagates ballistically. We characterize these processes through local observables, entanglement entropy, and the information lattice.

    Comments:
    4 pages (without ref), 1 figure, Proceedings of the 2025 International Conference on the Structure of Baryons (Baryons 2025), 10-14 Nov. 2025, Jeju, South Korea
    Subjects:
    High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
    arXiv:
    2604.06716 [pdf]
    J.Subatomic Part.Cosmol.(2026)·0 citations
  4. 07

    [Submitted on 8 Apr 2026] (cross-list from nucl-ex)

    Measurement of inclusive polarization in Ru+Ru and Zr+Zr collisions at GeV at STAR

    STAR Collaboration

    The first measurement of inclusive J/psi polarization at mid-rapidity (|y^{J/psi}| < 0.8) in 200 GeV Ru+Ru and Zr+Zr collisions at sqrt(s_NN) = 200 GeV with the STAR experiment at RHIC is presented. J/psi mesons are reconstructed through their di-electron (e+e-) decay channel. The polarization parameters (lambda_theta, lambda_phi) are measured as a function of the J/psi transverse momentum (p_T) and collision centrality in both the helicity and the Collins-Soper frames. These polarization parameters are found to be consistent with zero across the measured J/psi p_T range of 0.2 < p_T < 10 GeV/c and across collision centralities within 0-80 percent in both frames. These results are consistent with corresponding measurements p+p collisions at the same collision energy and with transport-model calculations.

    Subjects:
    Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2604.07005 [pdf]
    0 citations
  5. 08

    [Submitted on 8 Apr 2026] (cross-list from hep-ph)

    QED radiative corrections in inverse beta decay from virtual pions

    Oleksandr Tomalak🇨🇳

    Inverse beta decay (IBD), , is the main detection channel for reactor and supernova antineutrinos. To provide precise IBD cross sections at antineutrino energies , we evaluate radiative corrections from virtual pions within the framework of heavy baryon chiral perturbation theory. At leading order, only the pion isospin-breaking contributions are not suppressed by the electron mass. At next-to-leading order, besides recoil effects, only the Wilson coefficient contributes to the kinematic dependence. However, its precise value is not relevant for IBD at relatively low energies since all next-to-leading order radiative corrections are relatively small. We find the kinematic dependence of the pion-induced QED radiative corrections at the level and below the uncertainty from the momentum dependence of the nucleon form factors. Our results enable sub-permille theoretical precision of charged-current elastic (anti)neutrino-nucleon scattering at antineutrino energies .

    Comments:
    20 pages, 9 figures, journal version, brief summary to section 4 added, equation 3.19 corrected, minor text changes
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2604.07113 [pdf]
    JHEP(2026)·2 citations
  6. 09

    [Submitted on 8 Apr 2026] (cross-list from nucl-ex)

    Recent ALICE results from light-ion collision systems

    Abhi Modak (on behalf of the ALICE Collaboration)🇮🇹

    This article presents recent measurements by the ALICE Collaboration in proton--oxygen (pO), oxygen--oxygen (OO), and neon--neon (Ne--Ne) collisions delivered by the LHC in July 2025. Measurements of the primary charged-particle pseudorapidity density and the elliptic and triangular flow coefficients of charged particles are reported. Experimental evidence of the suppression of neutral pion yields in OO collisions relative to the proton--proton baseline is also discussed. Comparisons of these new data with theoretical models provide key input to understand particle production, collective phenomena, and parton energy loss in small collision systems.

    Comments:
    8 pages, 4 figures; Conference proceedings the 32 Cracow Epiphany Conference on the recent results from Heavy Ion Physics
    Subjects:
    Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
    arXiv:
    2604.07184 [pdf]
    2 citations
  7. 10

    [Submitted on 8 Apr 2026] (cross-list from hep-ph)

    Light mesons in the symmetric-vertex approximation

    M.N. Ferreira🇧🇷 · A.S. Miramontes🇪🇸 · J.M. Morgado🇪🇸 · J. Papavassiliou🇪🇸

    We compute the spectrum of light mesons, composed by up, down, and strange quarks, using a symmetry-preserving approximation that permits the inclusion of fully-dressed quark-gluon vertices in the key dynamical equations. This method is characterized by the use of the standard symmetric kinematic configuration as a seed in the corresponding Schwinger-Dyson equation, yielding finally the full kinematic dependence of all eight form factors composing the transversely-projected quark-gluon vertex. The extension of this approach to the case of distinct nonvanishing current quark masses is discussed, and the compatibility with the fundamental Ward-Takahashi identities demonstrated. The corresponding Bethe-Salpeter kernel is composed by three different diagrammatic structures, which may be deduced from the attendant quark gap equation by applying the standard "cutting" rules. The masses of the light mesons are computed by first determining the eigenvalue of the Bethe-Salpeter equation as a function of Euclidean momenta, and then using the Schlessinger extrapolation method to determine the Minkowski momentum for which this eigenvalue becomes unity. The resulting meson masses are in good agreement with experimental values, and substantially improve upon predictions from the rainbow-ladder approximation.

    Comments:
    33 pages, 12 Figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
    arXiv:
    2604.07221 [pdf]
    EPJC(2026)·7 citations

Affiliations

first authorsco-authorsvia INSPIRE