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Nuclear Theory·nucl-th

Friday·August 29, 2025

14 papers—7 primary·7 cross-listed

All14Primary7Cross-lists7
  1. 08

    [Submitted on 28 Aug 2025] (cross-list from hep-ph)

    Signals for fluctuating constituent numbers in small systems

    Andreas Kirchner🇺🇸 · Steffen A. Bass🇺🇸

    We propose an extension of the initial condition model TRENTo for sampling the number of partons inside the nucleons that participate in a heavy-ion collision. This sampling method is based on parton distribution functions (PDFs) and therefore has a natural dependence on the momentum transferred in the collision and the scale being probed during the collision. We examine the resulting distributions and their dependence on the momentum transfer. Additionally, we explore the sensitivity of different observables on the number of partons using the TRENTo framework and the estimators available therein for final-state observables.

    Comments:
    8 pages, 10 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2508.20390 [pdf]
    1 citation
  2. 09

    [Submitted on 28 Aug 2025] (cross-list from hep-ph)

    Electromagnetic properties of heavy-light mesons

    A. S. Miramontes🇪🇸 · J. Papavassiliou🇪🇸 · J. M. Pawlowski🇩🇪

    Within the Bethe-Salpeter framework, we present a computation of space-like electromagnetic form factors for pseudoscalar mesons, including light and heavy-light systems. Our approach employs a flavour-dependent variation of the standard Taylor effective charge, which contains key contributions from the quark-gluon vertices. This effective interaction is a common ingredient of all relevant dynamical equations, and accommodates the crucial mass differences between the various quark flavours. Particular attention is paid to the nonperturbative determination of the quark-photon vertex. The computed electromagnetic form factors for the pion and the kaon mesons show excellent agreement with experimental determinations. In addition, the predictions for the charge radii of heavy-light systems are in overall good agreement with lattice QCD.

    Comments:
    22 pages, 9 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
    arXiv:
    2508.20631 [pdf]
    EPJC(2025)·10 citations
  3. 10

    [Submitted on 28 Aug 2025] (cross-list from hep-ph)

    The (3+1)D structure of the dilute Glasma

    Andreas Ipp🇦🇹 · Markus Leuthner🇦🇹 · David I. Müller🇦🇹 · Sören Schlichting🇩🇪 · Kayran Schmidt🇦🇹 · Pragya Singh🇫🇮

    We study the (3+1)D structure of the Glasma in the dilute approximation, which allows us to describe the longitudinal dynamics that arise from the three-dimensional nuclear structure. We employ a nuclear model with tunable longitudinal and transverse fluctuation scales that generalizes the McLerran-Venugopalan model. We discuss the longitudinal profiles of the energy-momentum tensor and the transverse structure of the local rest frame energy density.

    Comments:
    4 pages, 2 figures, parallel talk given at the Quark Matter 2025 conference
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2508.20725 [pdf]
    EPJ Web Conf.(2026)·1 citation
  4. 11

    [Submitted on 28 Aug 2025] (cross-list from hep-ph)

    Updated Astrophysical Equation-of-State Constraints on the Color-Superconducting Gap

    Aleksi Kurkela🇳🇴 · Krishna Rajagopal🇺🇸 · Rachel Steinhorst🇺🇸

    We summarize and update using new NICER measurements the results of arXiv:2401.16253, in which we used various astrophysical neutron-star observations to set an upper bound on the CFL color-superconducting gap in a range of baryon chemical potentials , above those reached within neutron stars. We also corroborate the ``reasonable" constraint from arXiv:2401.16253 on the maximum value of the color-superconducting gap by performing a new Bayesian analysis using a prior that extends a two-segment Gaussian process connecting the whole density range between CEFT and pQCD.

    Comments:
    5 pages, 2 figures, proceedings of Quark Matter 2025
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
    arXiv:
    2508.20763 [pdf]
    EPJ Web Conf.(2026)·1 citation
  5. 12

    [Submitted on 28 Aug 2025] (cross-list from hep-ph)

    Impact of new results from the ultraperipheral collision on modeling the proton and neutron emission in photon-induced nuclear processes

    P. Jucha🇵🇱 · K. Mazurek🇵🇱 · A. Szczurek🇵🇱 · K. Pysz🇵🇱

    The ultrarelativistic collisions of heavy ions provide rich spectrum of possibilities to discuss the response of the nucleus to photons. Newly published neutron and proton multiplicities measured in the ALICE experiment in ultraperipheral collisions allow investigating the influence of the electromagnetic fields on colliding nuclei for the Pb+Pb at =5.02~TeV. The theoretical predictions are done within hybrid model including equivalent photon approximations (EPA), GiBUU modeling of pre-equilibrium processes and generation of the exited nuclear remnants, which decay is modeled by statistical approach: GEM2 or GEMINI++. The cross-sections of the mass-charge distributions of nuclear remnants as well as the neutron, proton and other charged particle multiplicities are estimated. We concentrate on production of protons and isotopes coming from the electromagnetic dissociation. Special attention is devoted to emission of a single proton. The cross section for emission is very close to maximal available one based on reactions of photon with individual nucleons. Our pre-equilibrium processes explain simultaneously the tail of neutron energy distributions in the nuclear rest frame observed in collisions.

    Comments:
    17 pages, 13 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2508.20791 [pdf]
    PRC(2026)·0 citations
  6. 13

    [Submitted on 28 Aug 2025] (cross-list from math.NA)

    Curvilinear coordinates and curvature in radiative transport

    Johannes Krotz · Ryan G. McClarren

    We derive a general expression for the streaming term in radiative transport equa- tions and other transport problems when formulated in curvilinear coordinates, emphasizing coordinate systems adapted to the geometry of the domain and the directional dependence of particle transport. By parametrizing the angular vari- able using a local orthonormal frame, we express directional derivatives in terms of curvature-related quantities that reflect the geometry of underlying spatial man- ifolds. Our formulation highlights how the interaction between coordinate choices and curvature influences the streaming operator, offering geometric interpretations of its components. The resulting framework offers intuitive insight into when and how angular dependence can be simplified and may guide the selection of coordinate systems that balance analytical tractability and computational efficiency.

    Subjects:
    math.NA (math.NA); cs.NA (cs.NA); math.AP (math.AP); Nuclear Theory (nucl-th)
    arXiv:
    2508.20852 [pdf]
    0 citations
  7. 14

    [Submitted on 28 Aug 2025] (cross-list from hep-ph)

    Deep learning for jet modification in the presence of the QGP background

    Ran Li🇨🇳 · Yi-Lun Du🇨🇳 · Shanshan Cao🇨🇳

    Jet interactions with the color-deconfined QCD medium in relativistic heavy-ion collisions are conventionally assessed by measuring the modification of the distributions of jet observables with respect to their baselines in proton-proton collisions. Deep learning methods enable per-jet evaluation of these modifications, enhancing the use of jets as precision probes of the nuclear medium. In this work, we predict the jet-by-jet fractional energy loss for jets evolving through a quark-gluon plasma (QGP) medium using a Linear Boltzmann Transport (LBT) model. To approximate realistic experimental conditions, we embed medium-modified jets in a thermal background and apply Constituent Subtraction for background removal. Two network architectures are studied: convolutional neural networks (CNNs) using jet images, and dynamic graph convolutional neural networks (DGCNNs) using particle clouds. We find that CNNs achieve accurate predictions for background-free jets but degrade in the presence of the QGP background and remain below the background-free baseline even after background subtraction. In contrast, DGCNNs applied to background-subtracted particle clouds maintain high accuracy across the entire range, demonstrating the advantage of point-cloud-based graph neural networks that exploit full jet structure under realistic conditions.

    Comments:
    10 pages, 8 figures. Updated version for the publication in PRC
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2508.20856 [pdf]
    PRC(2026)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE