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Nuclear Theory·nucl-th

Wednesday·March 26, 2025

11 papers—5 primary·6 cross-listed

All11Primary5Cross-lists6
  1. 01

    Tables of Neutron Thermal Cross Sections, Westcott Factors, Resonance Integrals, Maxwellian Averaged Cross Sections, Astrophysical Reaction Rates, and r-process Abundances Calculated from Evaluated Nuclear Data Libraries

    B. Pritychenko

    We present calculations of neutron thermal cross sections, Westcott factors, resonance integrals, Maxwellian-averaged cross sections, astrophysical reaction rates, and solar system -process abundances using the latest data from the major evaluated nuclear libraries for 849 ENDF target materials. The recent release of ENDF/B-VIII.1 library, progress in Cf(SF) evaluation, extensive analysis of newly-evaluated neutron reaction cross sections, neutron covariances, and improvements in data processing techniques motivated us to calculate the nuclear industry and neutron physics parameters, produce -process Maxwellian-averaged cross sections and astrophysical reaction rates, extract -process abundances, systematically calculate uncertainties, and provide additional insights on currently available neutron-induced reaction data.

    nucl-thAtom.Data Nucl.Data Tabl.(2025)·4 citations
  2. 02

    Spherical and Deformed Shell Effect Competition in Quasifission of Superheavy Nuclei

    Richard Gumbel · Kyle Godbey

    Quasifission, along with fusion-fission, represent the two most likely reaction outcomes to occur post-capture in collisions leading to superheavy nuclei. As such, understanding these mechanisms and how they relate to one another is key to understanding the intricate dynamics that drive the formation (or dissociation) of the nascent compound nuclei formed in fusion reactions. This understanding directly translates to a more informed picture of suitable reaction partners and can provide vital information for experimental efforts to study the physics and chemistry of superheavy elements. In this work we report results from time-dependent simulations of Ca + U and Ti + Th reactions at incident energies just above the Coulomb barrier with a focus on the quasifission process that prevent the formation of a fully equilibrated Cn compound nucleus. We study these reactions systematically and consider a wide range of initial configurations to extract a robust estimate of primary fragment yields for the quasifission process. Multiple preferred exit channels are observed, with both spherical and deformed shell effects in the heavy and light fragments driving contributions to the production yields depending on the initial configuration of the system. Orientation effects of the deformed actinide targets are found to be a primary driver of which exit channels are populated. Furthermore, the impact of moving away from a doubly-magic projectile is explored with implications towards the reactions considered for current and future superheavy searches.

    nucl-thPRC(2025)·0 citations
  3. 03

    Deep learning approaches for nuclear binding energy prediction: a comparative study of RNN, GRU and LSTM Models

    Amir Jalili · Feng Pan · Ai Xi Chen · Jerry P. Draayer

    This study investigates the application of deep learning models-recurrent neural networks, gated recurrent units, and long short-term memory networks-for predicting nuclear binding energies. Utilizing data from the Atomic Mass Evaluation (AME2020), we incorporate key nuclear structure features, including proton and neutron numbers, as well as additional terms from the liquid drop model and shell effects. Our comparative analysis demonstrates that the gated recurrent units model achieves the lowest root-mean-square error ({\sigma}RMSE) of 0.326 MeV, surpassing traditional regression-based approaches. To assess model reliability, we validate predictions using the GarveyKelson relations, obtaining an error of 0.202 MeV, and further test extrapolation capabilities using the WS, WS3, and WS4 models. The extrapolation analysis confirms the robustness of our approach, particularly in predicting binding energies for nuclei near the driplines. These results highlight the effectiveness of deep learning in nuclear BE predictions, highlighting its potential to enhance the accuracy and reliability of theoretical nuclear models.

    nucl-thPRC(2025)·8 citations
  4. 04

    I-C-Q relations for rapidly rotating stable hybrid stars

    Sujan Kumar Roy · Gargi Chaudhuri

    A number of hadronic equations of state for neutron stars have been investigated for the purpose of the present paper, considering the fact that at sufficiently high density, heavy baryons and quark phases may appear. The observational limits from NICER, GW170817, etc., are obeyed by our choice of equations of state. The universal relations are investigated for both slowly and rapidly rotating neutron stars with heavy baryons present inside the core. For slowly rotating stars, the universality of the I-Love-Q relations is verified, and the I-C-Q relations are inferred to be universal for rapidly rotating stars. Further, we extend the investigation to obtain the universal relations for compact stars containing the quark core, where the connected stable branch of such hybrid stars is considered. The parameters of the I-Love-Q and I-C-Q universal relations are obtained for slowly rotating and rapidly rotating hybrid stars, respectively. These relations would enable extracting information, within the context of general relativity, from astrophysical systems involving rapidly rotating neutron stars.

    nucl-thgr-qcAstropart.Phys.(2025)·5 citations
  5. 05

    Quantum molecular dynamics model based on relativistic mean field theory for light nucleus fragmentation in hadron therapy

    Akihiro Haga · Yoshi-hide Sato · Hana Fujiwara · Dousatsu Sakata · David Bolst · Edward C. Simpson · Susanna Guatelli

    This study evaluates the accuracy of nuclear fragmentation simulations using a quantum molecular dynamics (QMD) model based on relativistic mean field (RMF) theory for an energy range of 50-400 MeV/u, relevant to hadron therapy. A total of 16 parameter sets within the RMF framework are assessed based on their ability to reproduce ground-state properties such as the mean squared radius and binding energy, as obtained in QMD simulations. Among these, the NS2 parameter set is identified as the most suitable for describing stable nuclei over a wide mass range, with the use of an adaptive Gaussian wave packet width. Fragmentation cross sections of carbon ion projectiles on light nuclei targets (H, C, O, Al, Ti, and Cu) are simulated at incident energies of 50, 95, 290, and 400 MeV/u and compared with experimental data. The results indicate that the RQMD.RMF model provides superior reproductions for fragmentation at lower energies (50 and 95 MeV/u) compared to the Light Ion QMD (LIQMD) model implemented in Geant4 version 11.2. At higher energies (290 and 400 MeV/u), the RQMD.RMF model performs comparably to the LIQMD. This study demonstrates that the RQMD.RMF model provides a reliable framework for analyzing nuclear fragmentation and holds potential for applications in the planning and quality assurance of hadron therapy.

    nucl-thPRC(2025)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE