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Nuclear Theory·nucl-th

Monday·October 6, 2025

9 papers—7 primary·2 cross-listed

All9Primary7Cross-lists2
  1. 01

    Implications of a Weakening N = 126 Shell Closure Away from Stability for r-Process Astrophysical Conditions

    Mengke Li · Gail C. McLaughlin · Rebecca Surman

    The formation of the third r-process abundance peak near A = 195 is highly sensitive to both nuclear structure far from stability and the astrophysical conditions that produce the heaviest elements. In particular, the N = 126 shell closure plays a crucial role in shaping this peak. Experimental data hints that the shell weakens as proton number departs from Z = 82, a trend largely missed by global mass models. To investigate its impact on r-process nucleosynthesis, we employ both standard global models with strong closures and modified Duflo-Zuker (DZ) models that reproduce the weakening, combined with three sets of beta minus decay rates. Strong shell closures generate sharply peaked abundances, whereas weakened closures consistent with the experimental trend produce broader, flatter patterns. Accurately reproducing the solar third peak under weakened shell strength requires highly neutron-rich conditions (Ye <= 0.175) and slower decay rates. These results demonstrate that a weakening N = 126 shell closure away from stability imposes significant constraints on the astrophysical environments of the r-process and underscores the need for precise mass measurements and improved characterization of beta minus decay properties in this region.

    nucl-thPLB(2026)·4 citations
  2. 02

    Role of universal function of the nuclear proximity potential: A systematic study on the alpha-decay of heavy/super-heavy nuclei and {\alpha}-induced reactions

    S. Mohammadi · R. Gharaei · S. A. Alavi

    The idea of the universal function is fundamental advantage of proximity potential model. We present a systematic study of the role of universal function of the proximity potential model on alpha decay process for 250 ground state to ground state transitions using WKB approximation. In order to realize this goal, five universal functions proposed in the proximity models gp 77, Guo 2013, Ngo 80, Zhang 2013 and Prox. 2010 have been incorporated into the formalism of Prox. 77. The obtained results show that the radial behavior of universal function affects the penetration probability of the {\alpha} particle. The theoretical {\alpha} decay half lives are calculated and compared with the corresponding experimental data. It is shown that the Prox. 77 with Guo 2013 universal function provides the best fit to the available data. The role of the different universal functions in the {\alpha} decay half lives of super heavy nuclei (SHN) with Z from 104 to 118 are also studied. It is shown that the experimental half lives in the super heavy mass region are described well using the Prox. 77 with Zhang 2013 universal function. In this paper, the validity of the original and modified forms of the proximity 77 potential is also examined for complete fusion reactions between {\alpha} particle and 10 different target nuclei. Our results show that the measured {\alpha} induced fusion reaction cross sections can be well reproduced using the Prox. 77 with Zhang 2013 universal function for the reactions involving light and medium nuclei. Whereas, the Prox. 77 with Guo 2013 universal function model demonstrates a reliable agreement with the experimental data at sub-barrier energies for heavier systems.

    nucl-thhep-phnucl-exPRC(2025)·1 citation
  3. 03

    Imprints of dynamic fluidization on dilepton production

    Renan Góes-Hirayama🇩🇪 · Zuzana Paulínyová🇸🇰 · Joscha Egger🇩🇪 · Iurii Karpenko🇨🇿 · Hannah Elfner🇩🇪

    We present a newly developed hybrid hadronic transport + hydrodynamics framework geared towards heavy ion collisions at low to intermediate beam energies, and report on the resulting excitation function of dileptons. In this range of energies, it is unclear how to properly initialize the hydrodynamic evolution. Due to the cumulative electromagnetic radiation throughout the collision, dilepton observables are sensitive to the initial condition. In this work, we study how the dilepton ``thermometer'' is affected by employing dynamical initial conditions, in contrast to the traditional fixed-time approach.

    nucl-thhep-phEPJ Web Conf.(2026)·2 citations
  4. 04

    Production of spectator neutrons, protons and light fragments on fixed targets at NICA

    A.O. Svetlichny (1 and 2)🇷🇺 · E.Y. Vasyagina (1 and 2)🇷🇺 · S.D. Savenkov (1 and 2)🇷🇺 · I.A. Pshenichnov (1 and 2) ((1) Institute for Nuclear Research, Russian Academy of Sciences, Moscow, Russia, (2) Moscow Institute of Physics and Technology, Dolgoprudny, Russia)🇷🇺

    The Ultrarelativistic Quantum Molecular Dynamics (UrQMD) model was connected to a set of models called Ablation Monte Carlo (AMC) to identify excited spectator fragments on completion of the UrQMD modeling of nucleus-nucleus collisions and then simulate spectator decays. The UrQMD-AMC approach combines the Minimum Spanning Tree (MST) clustering algorithm, which associates individual nucleons with excited clusters termed prefragments, with decay models of excited nuclei from the Geant4 toolkit. The relevant decay model for the prefragments decay is selected based on their mass and excitation energy, and includes nuclear evaporation, statistical multifragmentation, and Fermi breakup models. The UrQMD-AMC approach was validated by comparing its results with data on the rapidity and transverse momentum distributions of neutrons and light fragments from 600A MeV Sn + Sn and 10.6A GeV Au + Ag collisions. This approach supplements the evolution of individual nucleons during a nucleus-nucleus collision simulated with UrQMD with nucleon clustering to simulate also the production of spectator nuclear fragments, which are not produced in the UrQMD model alone.

    nucl-thIJMPE(2026)·1 citation
  5. 05

    Principal Components of Nuclear Mass Model Residuals

    Y. Y. Huang · X. H. Wu

    Principal Component Analysis (PCA) is applied to the residuals of six widely used nuclear mass models to uncover systematic deviations and identify missing physical effects in theoretical nuclear mass predictions. By analyzing the principal components of nuclear mass model residuals, this study reveals that no single dominant pattern governs the discrepancies across models. Instead, the residual structures are largely uncorrelated, indicating that current nuclear mass models fail to capture underlying nuclear residual effects in distinct and model-specific ways. These findings suggest that improvements to nuclear mass models should be guided by model-specific residual analyses rather than a one-size-fits-all approach.

    nucl-thnucl-exPLB(2026)·0 citations
  6. 06

    Predictions in modified Glauber model of total charged-particle yields centrality dependence in O+O and Ne+Ne collisions at LHC

    Svetlana Simak · Grigory Feofilov

    In this article we present the results of application of the Monte Carlo modified Glauber model for the predictions of collision centrality dependence of the total charged-particle yields for 16O +16O and 20Ne+20Ne colliding systems at the LHC. Our model differs from the Standard Glauber model by the effective account of the energy losses in successive inelastic nucleon-nucleon collisions. For this purpose, a single model parameter k is defined as a mean fraction of the momentum loss that happens in any binary nucleon collision due to the production of multiple particles. Therefore, the decrease of the nucleon momentum after each inelastic collision leads to a corresponding reduction of the inelastic cross section and the mean multiplicity yield in the subsequent interaction. All these effects are taken into account in the MC model in each of the subsequent inelastic binary interactions. We discuss the purely geometrical effects for these light colliding systems that could be considered useful in future studies of QGP properties in energy density scanning. Predictions in this single parameter model are based on the previous successful analysis of non-linear centrality dependence of charged particle yields observed in Pb+Pb collisions by ALICE at the LHC.

    nucl-thhep-ph0 citations
  7. 07

    Application of the holographic equations of state for modeling experiments on heavy ion collisions

    A. V. Anufriev🇷🇺 · V. N. Kovalenko🇷🇺

    In this paper, we propose a method for numerical modeling of the nuclear matter properties within the framework of relativistic heavy-ion collisions using a holographic equation of state. Machine learning methods were applied to address the regression and optimization issues during the calibration of the relevant parameters using the LQCD results for quark masses that approximate the physical values. Numerical simulations are performed using the iEBE-MUSIC and vHLLE-SMASH frameworks, which incorporate certain relativistic hydrodynamics solvers. We modify the code by implementing a tabulated holographic equation of state, enabling simulations of quark-gluon plasma evolution with dynamically generated initial conditions via the 3D Monte Carlo Glauber Model and SMASH. Finally, the spectra of produced hadrons are computed using a hybrid iSS+UrQMD and Hadron Sampler+SMASH approaches at the freeze-out stage.12 p

    nucl-thgr-qchep-phhep-thIJMPE(2026)·1 citation

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first authorsco-authorsvia INSPIRE