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Nuclear Theory·nucl-th

Wednesday·October 22, 2025

7 papers—5 primary·2 cross-listed

All7Primary5Cross-lists2
  1. 01

    [Submitted on 21 Oct 2025]

    Nonlocality Effect in the Tunneling of Alpha Radioactivity with the Aid of Machine Learning

    Jinyu Hu🇨🇳 · Chen Wu🇨🇳

    Recently, building upon the research findings of E. L. Medeiros, we have extended the alpha-particle non-locality effect to the two-potential approach (TPA). This extension demonstrates that the integration of the alpha-particle nonlocality effect into TPA yields relatively favorable results. In the present work, we employ machine learning methods to further optimize the aforementioned approach, specifically utilizing three classical machine learning models: decision tree regression, random forest regression, and XGBRegressor. Among these models, both the decision tree regression and XGBRegressor models exhibit the highest degree of agreement with the reference data, whereas the random forest regression model shows inferior performance. In terms of standard deviation, the results derived from the decision tree regression and XGBRegressor models represent improvements of 54.5% and 53.7%, respectively, compared to the TPA that does not account for the coordinate-dependent effective mass of alpha particles. Furthermore, we extend the decision tree regression and XGBRegressor models to predict the alpha-decay half-lives of 20 even-even nuclei with atomic numbers Z=118 and Z=120. Subsequently, the superheavy nucleus half-life predictions generated by our proposed models are compared with those from two established benchmarks: the improved eight-parameter Deng-Zhang-Royer (DZR) model and the new empirical expression (denoted as "New+D") proposed by V. Yu. Denisov, which explicitly incorporates nuclear deformation effects. Overall, the predictions from these models and formulas are generally consistent. Notably, the predictions of the decision tree regression model show a high level of consistency with those of the New+D expression, while the XGBRegressor model exhibits deviations from the other two comparative models.

    Comments:
    12 pages, 5 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2510.18199 [pdf]
    EPJA(2026)·1 citation
  2. 02

    [Submitted on 21 Oct 2025]

    Neutron emission during fission and its impact on fission-fragment mass distribution studied by Langevin model

    S. Takagi · S. Harada · Y. Aritomo · K. Hirose · K. Nishio

    Actinide nuclei exhibit mass-asymmetric fission at low energy due to shell structure. The fission-fragment mass distributions produced at high energy tend to have a symmetric shape due to smearing of shell effects. On the other hand, the distribution can be changed by neutron emission occurring before fission, as this decreases the excitation energy of the fissioning nucleus, and thus revives the shell structure. In so called multichance fission, neutron emission is considered prior to fission at the initial nuclear shape, and competition between fission and neutron emission is determined with the framework of the statistical model. In the present work, we describe fission in the Langevin equations, and neutron emission is treated throughout the fission process. The calculation reproduces experimentally observed mass distributions, and for a wide range of initial compound-nucleus excitation energy up to 60 MeV. The results show that, while neutron emission dominates at the ground-state shape, it occurs along the shape evolution path to the scission point.

    Comments:
    Published in Physical Review C on 20 October, 2025. 9 pages, 5 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2510.18205 [pdf]
    PRC(2025)·1 citation
  3. 03

    [Submitted on 21 Oct 2025]

    Probing momentum dependence of hydrodynamization in heavy-ion collisions

    Akihiko Monnai🇯🇵

    The fluidity of the hot and dense QCD matter is a key characteristic of the medium created in high-energy heavy-ion collisions. We extend the framework of the relativistic hydrodynamic model to incorporate non-thermal momentum distributions that may emerge during the dynamical evolution of the collision system. Numerical simulations are performed to elucidate the phenomenological implications of these modifications on charged hadrons and direct photons measured in collider experiments.

    Comments:
    4 pages, 4 figures; Proceedings of the 29th International Nuclear Physics Conference (INPC 2025), May 25-30, 2025, Daejeon, South Korea
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2510.18522 [pdf]
    EPJ Web Conf.(2026)·0 citations
  4. 04

    [Submitted on 21 Oct 2025]

    -decay systematics for superheavy nucleus: the effect of deformation of daughter nucleus

    Jinyu Hu🇨🇳 · Chen Wu🇨🇳

    Recently, V.Yu. Denisov proposed a new empirical formula incorporating the deformation of the daughter nucleus, which has significantly improved the description of -decay half-lives for even-even nuclei compared to formulas neglecting the deformation of the daughter nucleus. In this work, we generalize the deformation of the daughter nucleus proposed by V.Yu. Denisov to the DUR model, the AKRA model, the New Geiger-Nuttall law, generating three improved versions of these models. We then employ both the original and modified the DUR model, the AKRA model, and the New Geiger-Nuttall law to investigate the -decay half-lives of 400 isotopes. Results show that among the six models, the modified AKRA model provides the closest agreement with experimental -decay half-life data. For comparative analysis, we use the new empirical formulas developed for the DUR model (DUR+D), the AKRA model (AKRA+D) and a new empirical (ND) proposed by V.Yu. Denisov to predict the -decay properties of 71 even-even nuclei with Z = 118, 120, 122, and 124. The predictions from the DUR+D model, the AKRA+D model, and ND are largely consistent overall. Notably, when the neutron number , the predictions from the DUR+D model and the AKRA+D model exceed those of ND, which may be attributed to additional physical contributions (e.g., the hexadecapole and the hexacontatetrapole deformation of the deformed daughter nucleus) incorporated in the DUR+D model and the AKRA+D model but not in ND.

    Comments:
    12 pages, 8 tables and 8 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2510.18577 [pdf]
    NPA(2026)·0 citations
  5. 05

    [Submitted on 21 Oct 2025]

    Charm-strange meson production in relativistic heavy ion collisions

    Sungtae Cho🇰🇷 · Su Houng Lee🇰🇷

    We study charm-strange mesons, or , , , and mesons by focusing on their production by coalescence from a quark-gluon plasma in relativistic heavy ion collisions at TeV. Starting from the investigation of the transverse momentum distribution of both charm and strange quarks through transverse momentum distributions of and mesons, we calculate the transverse momentum distributions and yields of , , , and mesons based on the coalescence model. We find that the yield and transverse momentum distribution of the meson agree well with the experimental measurements at TeV at LHC. We further evaluate the transverse momentum ratio between and mesons, and investigate the role of light and strange quarks in the production of charmed mesons in heavy ion collisions. Finally, we calculate the transverse momentum distribution and yield of the meson in a four-quark state, and compare to those of meson in a two-quark state.

    Comments:
    12 pages, 7 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2510.18673 [pdf]
    1 citation

Affiliations

first authorsco-authorsvia INSPIRE