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Nuclear Theory·nucl-th

Tuesday·April 28, 2026

14 papers—5 primary·9 cross-listed

All14Primary5Cross-lists9
  1. 01

    [Submitted on 25 Apr 2026]

    On the Cancellation of Nuclear Effects in the Valence Region

    S.A. Kulagin · R. Petti

    Deep-inelastic scattering data on targets ranging from deuterium to lead indicate that nuclear modifications to the structure functions of bound nucleons are minimal in the kinematic region where valence quark distributions peak. A global analysis of measurements of the isoscalar cross-section ratios in the range reveals a remarkable cancellation of nuclear effects across all nuclei, yielding a mean value of . We discuss these results and explore potential interpretations within a microscopic model for the nuclear modifications of the structure functions.

    Comments:
    17 pages, 7 figures, 2 tables
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2604.23110 [pdf]
    0 citations
  2. 02

    [Submitted on 27 Apr 2026]

    Nuclear non-resonant photoexcitation assisted by electron recombination

    Nan Xue · Zuoye Liu · Ziwen Li · Adriana Pálffy · Jianmin Yuan · Yuanbin Wu · Xiangjin Kong · Yu-Gang Ma

    We investigate theoretically a nuclear excitation mechanism involving absorption of non-resonant photons leveraged by the coupling to the atomic shell. The nuclear non-resonant photoexcitation is assisted by electron recombination which compensates the energy mismatch between photon and nuclear transition energies, reminiscent of parametric up-conversion in non-linear media. This third-order process proceeds via a virtual nuclear state rather than virtual electronic states, distinguishing this mechanism from the electronic bridge. We investigate the process on the example of a so-far not observed 14.2 keV hard x-ray transition in 193Pt driven by an x-ray free-electron laser. Although the calculated cross section is small, it can be compensated by the vast number of non-resonant photons from the x-ray laser pulse. By enabling nuclear excitation through non-resonant photons, this up-conversion-like mechanism suggests new directions for non-linear x-ray interactions mediated by nuclear transitions.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2604.24045 [pdf]
    SCPMA(2026)·0 citations
  3. 03

    [Submitted on 27 Apr 2026]

    Survival of Pairing Correlations and Shell Effects at Scission in Finite-Temperature Nuclear Fission: Implications for Odd-Even Staggering

    K. Pomorski · A. Augustyn · T. Cap · Y. J. Chen · M. Kowal · M. Warda · Z. G. Xiao

    We investigate the finite-temperature evolution of microscopic free-energy corrections in nuclear fission, focusing on pairing and shell effects near scission. The analysis is based on a finite-temperature BCS treatment combined with the Strutinsky method and is performed for representative deformation points along the fission path. Both pairing and shell contributions exhibit regular thermal attenuation, but their deformation dependencies differ substantially. In particular, pairing remains strongly deformation-dependent in the scission region, and its free-energy contribution differs markedly between the constant and surface-dependent pairing-strength prescriptions. The shell correction near scission is also significant at low temperature and is progressively suppressed with increasing excitation energy. These results support the interpretation of odd-even staggering in fragment charge yields as a manifestation of pairing correlations surviving into the strongly deformed pre-scission configuration. They also show that pairing and shell effects should be treated separately in finite-temperature dynamical calculations, with distinct deformation- and temperature-dependent attenuation laws.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2604.24174 [pdf]
    PRC(2026)·0 citations
  4. 04

    [Submitted on 27 Apr 2026]

    Field-theoretical description of the deuteron breakup in the clothed particle representation

    O. Shebeko🇺🇦 · A. Arslanaliev🇺🇦 · Y. Kostylenko🇺🇦 · V. Chahar🇵🇱 · J. Golak🇵🇱 · H. Kamada🇯🇵 · W. N. Polyzou🇺🇸 · D. Ramírez🇵🇱 · R. Skibiński🇵🇱 · K. Topolnicki🇵🇱 · H. Witała🇵🇱

    We present a field-theoretical description of the deuteron electrodisintegration reaction d(e,e'p)n induced by unpolarized and polarized electrons. The approach combines the Lehmann-Symanzik-Zimmermann in(out) formalism with the clothed particle representation in the instant form of relativistic dynamics, providing a fully relativistic and gauge-independent framework based on the Fock-Weyl criterion. Within the method of unitary clothing transformations, one and the same transformation that generates the relativistic nucleon-nucleon interaction (the Kharkiv potential) also induces a fresh family of electromagnetic current operators. As a result, one-body and two-body (meson-exchange) currents emerge on a common footing. We compute differential cross sections and polarization observables with the inclusion of final-state interaction effects and meson-exchange current contributions, and compare the results with Saclay and Jefferson Lab data as well as with earlier theoretical predictions. The role of relativistic ingredients (one- and two-body currents, Fermi-motion effects, etc.) and the interplay between them are analyzed in several kinematic regimes of the experiments at Saclay and Jefferson Lab.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2604.24457 [pdf]
    0 citations
  5. 05

    [Submitted on 27 Apr 2026]

    Neutrino Cross Sections: Low Energy

    Omar Benhar🇮🇹

    Low-energy neutrino interactions with isolated nucleons are accurately described by the effective theory based on Fermi's groundbreaking description of neutron -decay. On the other hand, the extension of this scheme to the case of neutrino interactions with nuclear matter -- the understanding of which is critical for the description of a variety of astrophysical processes -- involves non trivial difficulties, originating from the complexity of nuclear structure and dynamics. This chapter provides a concise introduction to the formalism of nuclear many-body theory, suitable to perform theoretical calculations of the nuclear matter response to neutrino interactions, as well as a detailed analysis of the relevant reaction mechanisms. The neutrino mean free path in nuclear matter and its implications for the description of astrophysical processes are also discussed.

    Comments:
    Paper prepared as a chapter of the forthcoming Encyclopedia of Particle Physics
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2604.24577 [pdf]
    0 citations

Affiliations

first authorsco-authorsvia INSPIRE