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Nuclear Theory·nucl-th

Thursday·April 3, 2025

12 papers—6 primary·6 cross-listed

All12Primary6Cross-lists6
  1. 01

    [Submitted on 2 Apr 2025]

    Proton cumulants from hydrodynamics in light of new STAR data

    Volodymyr Vovchenko🇺🇸 · Volker Koch🇺🇸

    New measurements of proton number cumulants from the Beam Energy Scan Phase II (BES-II) program at RHIC by the STAR Collaboration provide unprecedented precision and insights into the properties of strongly interacting matter. This report discusses the measurements in the context of predictions from hydrodynamics, emphasizing the enhanced sensitivity of factorial cumulants and their implications for the search for the QCD critical point. The experimental data shows enhancement of second-order factorial cumulants and suppression of third-order factorial cumulants relative to the non-critical baseline at GeV. We discuss implications of this observation for the possible location of the critical point in the QCD phase diagram and opportunities for future measurements of acceptance dependence of factorial cumulants.

    Comments:
    6 pages, 4 figures, presented at EMMI Workshop "Aspects of Criticality II" (July 2-4, 2024)
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2504.01368 [pdf]
    J.Subatomic Part.Cosmol.(2025)·5 citations
  2. 02

    [Submitted on 2 Apr 2025]

    A simple schematic model for a cross section deficit in C+C fusion reactions

    K. Hagino

    A cross section deficit phenomenon has been observed in C+C fusion reactions at astrophysical energies, at which fusion cross sections are suppressed in the off-resonance regions as compared to fusion cross sections for the C+C system. I here construct a simple schematic model which simulates this phenomenon. The model consists of a random matrix Hamiltonian based on the Gaussian Orthogonal Ensemble (GOE), which is coupled to an entrance channel Hamiltonian in the discrete basis representation. I show that the transmission coefficients are almost unity when both the level density and the decay widths of the GOE configurations are large, realizing the strong absorption regime. On the other hand, when these parameters are small, the transmission coefficients are significantly structured as a function of energy. In that situation, the transmission coefficients at resonance energies reach unity in this model, that is consistent with the experimental finding of the cross section deficit.

    Comments:
    5 pages, 5 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2504.01371 [pdf]
    0 citations
  3. 03

    [Submitted on 2 Apr 2025]

    Systematic study of {\alpha}-decay half-lives of superheavy nuclei based on Coulomb and proximity potential models with temperature effects

    Panpan Qi · Xuanpeng Xiao · Gongming Yu · Haitao Yang · Qiang Hu

    By employing the Coulomb proximity potential model (CPPM) in conjunction with 22 distinct proximity potential models, we investigated the temperature dependence and the effects of proton number and neutron number on the diffusion parameters that determine the {\alpha}-decay half-lives of superheavy nuclei. The results indicate that the Prox.77-3 T-DEP proximity potential model yields the best performance, with the lowest root mean square deviation ({\sigma}=0.515), reflecting a high consistency with experimental data. In contrast, Bass77, AW95, Ngo80, and Guo2013 display larger deviations. The inclusion of temperature dependence significantly improves the accuracy of models such as Prox.77-3, Prox.77-6, and Prox.77-7. The -decay half-lives of 36 potential superheavy nuclei were further predicted using the five most accurate proximity potential models and Ni's empirical formula, with the results aligning well with experimental data. These predictions underscore the high reliability of the CPPM combined with proximity potential models in the theoretical calculation of {\alpha}-decay half-lives of superheavy nuclei, offering valuable theoretical insights for future experimental investigations of superheavy nuclei.

    Comments:
    24 pages, 2 figures, 4 Tables
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2504.01401 [pdf]
    Eur.Phys.J.Plus(2026)·0 citations
  4. 04

    [Submitted on 2 Apr 2025]

    Reaction and interaction nucleus-nucleus cross sections in the complete Glauber theory

    Yu.M. Shabelski🇷🇺 · A.G. Shuvaev🇷🇺

    The straightforward calculations of the reaction and interaction cross sections of the nuclear scattering are carried out in Glauber approach using the generating function method. It allows for the resummation of all orders of Glauber theory. The results are obtained for He, Li, C scattering on C target. The difference between the reaction and the differential cross section is shown to be not exceeding several percents

    Comments:
    10 pages, no figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2504.01433 [pdf]
    0 citations
  5. 05

    [Submitted on 2 Apr 2025]

    A microscopic calculation of fission cross sections with the non-equilibrium Green function method

    K. Uzawa · K. Hagino

    We apply the non-equilibrium Green function (NEGF) method to microscopically evaluate fission cross sections for the neutron induced U reaction. While the model space was restricted only to seniority zero configurations in the previous applications of the NEGF method, we remove this restriction and include seniority non-zero configurations as well. In such model space, a proton-neutron interaction is active, for which we introduce a random interaction. We find that the seniority non-zero configurations significantly increase the fission cross sections, and thus the fission-to-capture branching ratios, even though they are still underestimated by about one order of magnitude as compared to the experimental data. In addition, we also find that the fission dynamics is governed by only a small number of eigenstates of the model Hamiltonian.

    Comments:
    12 pages, 12 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2504.01572 [pdf]
    PRC(2025)·1 citation
  6. 06

    [Submitted on 2 Apr 2025]

    Energy Density Functional of Confined Quarks: an Improved Ansatz

    Udita Shukla🇵🇱 · Pok Man Lo🇵🇱

    Density Functional Theory (DFT) is a robust framework for modeling interacting many-body systems, including the equation of state (EoS) of dense matter. Many models, however, rely on energy functionals based on assumptions that have not been rigorously validated. We critically analyze a commonly used ansatz for confinement, where the energy functional scales with density as . Our findings, derived from a systematic non-local energy functional, reveal that this scaling does not capture the dynamics of confinement. Instead, the energy functional evolves from at low densities to at high densities, governed by an infrared cutoff. These results suggest that models relying on such assumptions should be revisited to ensure more reliable EoS construction.

    Comments:
    typos corrected, version appears in JSPC
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th)
    arXiv:
    2504.01814 [pdf]
    J.Subatomic Part.Cosmol.(2025)·4 citations

Affiliations

first authorsco-authorsvia INSPIRE