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Nuclear Theory·nucl-th

Monday·September 29, 2025

6 papers—3 primary·3 cross-listed

All6Primary3Cross-lists3
  1. 01

    [Submitted on 25 Sept 2025]

    Neutron Skin from Conserved Charge Measurements at Collider Experiments

    Grégoire Pihan🇺🇸 · Akihiko Monnai🇯🇵 · Björn Schenke🇺🇸 · Chun Shen🇺🇸

    We propose a novel method for measuring the neutron skin of heavy nuclei using collider experiments. Specifically, we demonstrate that the neutron skin thickness of the lead nucleus can be extracted in +Pb collisions by analyzing a double ratio: The ratio of net electric charge to net baryon number measured near the lead-going rapidity, taken for high-multiplicity events and divided by the same ratio for low-multiplicity events. We compute the expected sensitivity of the double ratio to the neutron skin within a comprehensive (3+1)D relativistic hydrodynamic framework that incorporates multiple conserved charge currents and a charge-dependent lattice-QCD-based equation of state. We provide predictions for both +Pb collisions at ~GeV and ~TeV, corresponding to the center of mass energies realized in the SMOG2 fixed-target setup at LHCb and the LHC collider mode, respectively.

    Comments:
    6 pages, 3 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2509.21644 [pdf]
    7 citations
  2. 02

    [Submitted on 26 Sept 2025]

    Isoenergetic description of induced fission pathways within energy-density functional theory

    Alan A. Dzhioev · N. V. Antonenko

    A thermodynamically consistent description of induced fission pathways in the superheavy nucleus Lv is presented within the framework of nuclear energy-density functional theory. Using self-consistent finite-temperature Hartree-Fock-Bogoliubov calculations with the Skyrme-type energy-density functional SkM, we derive and compare effective potentials corresponding to different thermodynamic processes -- isothermal (), isentropic (), and isoenergetic () -- as functions of quadrupole deformation and excitation energy. At the same amount of excitation energy the isoenergetic description predicts the highest fission barrier and the largest damping factor. The suppression of the isoenergetic fission barrier is analyzed by examining how the driving force changes with increasing excitation energy and by studying the contribution of the nonpotential term to the effective potential. Within the framework of the three thermodynamic schemes considered, the different behavior of temperature and entropy along the fission pathway is also emphasized. A transition of the effective level-density parameter from a deformation-sensitive quantity at low excitation energies to a nearly constant value at high energies is observed, in line with the Fermi-gas model expectations.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2509.22006 [pdf]
    PRC(2025)·0 citations
  3. 03

    [Submitted on 26 Sept 2025]

    Cumulative proton production in collisions

    A.B. Larionov🇷🇺

    The model of backward proton production in the exclusive reaction at proton beam momenta up to several GeV/c is constructed on the basis of Feynman diagrams for one- and two-step amplitudes. The latter include nucleon and resonance intermediate scattering states with propagators reduced to eikonal form using the generalized eikonal approximation. The model calculations are compared with available experimental data on the energy spectra of protons at backward polar angles in the deuteron rest frame. It is shown that inclusion of two-step amplitudes significantly increases the production of backward protons with energies above 50 MeV, thereby significantly improving the agreement with experiment. The remaining theoretical problem related to the description of the off-shell behavior of the elementary amplitudes of the and transitions is discussed. Partial discrepancies between different sets of experimental data do not allow for conclusion that exotic effects, such as proton interactions with density fluctuations and/or clusters in the deuteron, are present.

    Comments:
    35 pages, 16 figures, discussion extended, conclusions unchanged, version accepted in Phys. Rev. C
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2509.22433 [pdf]
    PRC(2026)·1 citation
  4. 04

    [Submitted on 25 Sept 2025] (cross-list from astro-ph.HE)

    Stochastic analysis of ultra-high energy cosmic ray interactions

    Leonel Morejon🇩🇪 · Karl-Heinz Kampert🇩🇪

    Photonuclear interactions between ultra-high-energy cosmic ray (UHECR) nuclei and surrounding photon fields are key to understanding the connection between the compositions observed at Earth and those emitted from the sources. These interactions can completely disintegrate a nucleus of iron over trajectory lengths of a few and up to hundreds of megaparsecs, depending on the energy of the UHECR. The stochastic nature of these interactions means that it is not possible to describe them deterministically for a single cosmic ray, and an exact formulation of the probability distributions is not yet available. Current approaches describe these interactions using either Monte Carlo simulations or solving ordinary differential equations that neglect stochasticity. Because of the limitations of these approaches, only partial capture of the process is achieved. This paper presents an analytic probabilistic description of UHECR interactions and the resulting nuclear cascades, establishing their connection to Markov jump processes. The fundamental properties of these cascades are presented, as is the computation of the usual quantities of interest, such as the horizon, spectrum, and composition. The benefits of this description are outlined using astrophysical examples related to extragalactic propagation and UHECR sources.

    Comments:
    Accepted for publication in Astronomy & Astrophysics (A&A)
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2509.21461 [pdf]
    Astron.Astrophys.(2026)·1 citation
  5. 05

    [Submitted on 26 Sept 2025] (cross-list from hep-ph)

    Dynamical gluon effects in the three-dimensional structure of pion

    Jiangshan Lan🇨🇳 · Kaiyu Fu🇨🇳 · Satvir Kaur🇨🇳 · Zhimin Zhu🇨🇳 · Chandan Mondal🇨🇳 · Xingbo Zhao🇨🇳 · James P. Vary🇺🇸

    We investigate the internal structure of the pion, including the contributions from one dynamical gluon, using the basis light-front quantization (BLFQ) approach. By solving a light-front QCD Hamiltonian with a three-dimensional confining potential, we obtain the light-front wavefunctions (LFWFs) for both the quark-antiquark and quark-antiquark-gluon Fock sectors. These wavefunctions are then employed to compute the unpolarized generalized parton distributions (GPDs) and the transverse-momentum-dependent parton distributions (TMDs) of valence quarks and gluons. We also extract the transverse spatial distributions, providing the squared radii of quark and gluon densities in the impact-parameter space. This work contributes toward a three-dimensional understanding of the pion's internal structure in both momentum and coordinate space.

    Comments:
    23 pages, 9 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    2509.22016 [pdf]
    PRD(2026)·3 citations
  6. 06

    [Submitted on 26 Sept 2025] (cross-list from hep-ph)

    Recent progress in modeling neutrino-nucleus interactions for oscillation experiments

    Maria B. Barbaro🇮🇹

    The analysis of accelerator-based neutrino experiments crucially depends on the good control of nuclear effects in the neutrino interactions with the detectors. Recently the focus of both experimental measurements and theoretical studies has moved from the inclusive channel, where only the final lepton is detected, to the more challenging semi-inclusive reactions, where one or more hadrons are detected in coincidence with the lepton. In this contribution we present our recent research of the semi-inclusive reaction on carbon for the quasielastic and the two-particle-two-hole channels. We show some representative results and their comparison with experimental data, illustrating the robustness of the theoretical approach and discussing possible improvements to the model.

    Comments:
    6 pages, 3 figures. Submitted to MAYORANA (2025) conference proceedings
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2509.22371 [pdf]
    Nuovo Cim.C(2026)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE