Nuclear Physics A最新文献

英文中文

Accurate prediction of Gamow-Teller beta-decay matrix elements via machine learning: implications for nuclear structure 通过机器学习准确预测伽莫夫-泰勒β衰变矩阵元素：对核结构的影响

IF 2.5 4区物理与天体物理 Q2 PHYSICS, NUCLEAR

Nuclear Physics A

Pub Date : 2025-12-20 DOI: 10.1016/j.nuclphysa.2025.123318

Cafer Mert Yeşilkanat , Serkan Akkoyun

Accurate prediction of Gamow-Teller (GT) beta decay matrix elements [

M (G T)

] is essential for elucidating complex nuclear structure phenomena and understanding astrophysical processes. In this study, we employed five advanced machine learning models (Cubist, Support Vector Regression, Extreme Gradient Boosting, Random Forest, and Bayesian Regularized Neural Networks) to predict GT beta decay matrix elements in

s d

-shell nuclei, using experimental data from NNDC/ENSDF, NUBASE2016, and AME2016. This study systematically compared the predictive performance of traditional theoretical approaches (including the USDB, IM-SRG, CCEI, and CEFT) to that of advanced machine learning models trained based on experimental observations. Our primary objective was to determine whether data-driven models could achieve higher predictive accuracy than computationally expensive theoretical models by learning the complex and nonlinear relationships among experimental parameters that reflect nuclear structure and decay dynamics. The results demonstrate that the Cubist model achieves a significantly lower RMSE (0.073 in the full parameter modeling approach and 0.112 in the reduced parameter modeling approach) and high coefficients of determination (R² = 0.901 and 0.919, respectively), thereby outperforming traditional methods. Furthermore, SHapley Additive exPlanations (SHAP) analysis revealed that a minimal set of critical nuclear parameters predominantly governs GT decay dynamics, thereby enhancing model interpretability without compromising predictive accuracy. Complementing these findings, an online calculator was developed to facilitate rapid, high-fidelity predictions of GT matrix elements. Overall, our study demonstrates that a data-driven approach outperforms established theoretical models. More importantly, by identifying the minimal set of physical observables that govern GT transitions, our work provides crucial insights into the underlying physics of nuclear structure and offers a new benchmark for refining future theoretical models and astrophysical calculations.

准确预测Gamow-Teller (GT) β衰变矩阵元素[M(GT)]对于阐明复杂的核结构现象和理解天体物理过程至关重要。在这项研究中，我们使用了五种先进的机器学习模型（Cubist、支持向量回归、极端梯度增强、随机森林和贝叶斯正则化神经网络）来预测sd壳核中的GT β衰变矩阵元素，实验数据来自NNDC/ENSDF、NUBASE2016和AME2016。本研究系统地比较了传统理论方法（包括USDB、IM-SRG、CCEI和CEFT）与基于实验观察训练的先进机器学习模型的预测性能。我们的主要目标是通过学习反映核结构和衰变动力学的实验参数之间的复杂和非线性关系，确定数据驱动模型是否可以比计算昂贵的理论模型获得更高的预测精度。结果表明，立体主义模型的RMSE较低（全参数建模方法为0.073，约参数建模方法为0.112），决定系数较高（R²分别= 0.901和0.919），优于传统方法。此外，SHapley加性解释（SHAP）分析表明，最小的临界核参数集主要控制GT衰变动力学，从而在不影响预测精度的情况下提高模型的可解释性。为了补充这些发现，开发了一个在线计算器，以促进快速、高保真地预测GT矩阵元素。总体而言，我们的研究表明，数据驱动的方法优于已建立的理论模型。更重要的是，通过确定控制GT跃迁的最小物理观测集，我们的工作为核结构的潜在物理提供了至关重要的见解，并为完善未来的理论模型和天体物理计算提供了新的基准。

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引用次数: 0

Exploring the effect of entrance channel mass asymmetry in the fission of 197Tl* nucleus 探讨入口通道质量不对称对197Tl*核裂变的影响

IF 2.5 4区物理与天体物理 Q2 PHYSICS, NUCLEAR

Nuclear Physics A

Pub Date : 2025-12-18 DOI: 10.1016/j.nuclphysa.2025.123310

Golda Komalan Satheedas , H. Singh , Kavita Kavita , Mohit Kumar , N. Saneesh , A. Jhingan , P. Sugathan , C. Yadav , R. Kumar , R. Dubey , Abhishek Yadav , Neeraj Kumar , A. Banerjee , Anjali Rani , Kavita Rani , J.R. Acharya , S. Noor , S.K. Duggi

Fission fragment mass ratio distributions have been measured for the reactions ¹⁹F+¹⁷⁸Hf and ¹⁶O + ¹⁸¹Ta, both leading to the same compound nucleus, ¹⁹⁷Tl, at near-Coulomb barrier energies. The measured fission fragment mass width for both these systems does not show any substantial deviation from the statistical model predictions, which indicates the absence of non-compound nuclear reactions like quasi-fission. The measured mass widths of both the reactions at the same excitation energy are comparable within the experimental uncertainty and show a gradual increase with excitation energy. No noticeable influence of effect of entrance channel mass asymmetry on fragment mass distribution in these reactions, which differs from the previously reported entrance channel-dependent variation in average pre-scission neutron multiplicity.

对19F+178Hf和16O + 181Ta反应的裂变碎片质量比分布进行了测量，这两个反应都在近库仑势垒能下生成了相同的化合物核197Tl。这两种体系的裂变碎片质量宽度的测量结果与统计模型的预测没有任何实质性的偏差，这表明不存在像准裂变这样的非复合核反应。在相同激发能下，两种反应的测量质量宽度在实验不确定度范围内具有可比性，且随激发能的增加而逐渐增大。在这些反应中，入口通道质量不对称对碎片质量分布没有明显的影响，这与之前报道的平均裂变前中子多重度随入口通道的变化不同。

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引用次数: 0

Observation of novel features in heavy-ion induced fission using charged particle emissions 利用带电粒子发射观察重离子诱导裂变的新特征

IF 2.5 4区物理与天体物理 Q2 PHYSICS, NUCLEAR

Nuclear Physics A

Pub Date : 2025-12-18 DOI: 10.1016/j.nuclphysa.2025.123315

Y.K. Gupta , G.K. Prajapati , Pawan Singh , N. Sirswal , B.N. Joshi

Despite substantial advances in nuclear physics, certain subtle aspects remain unresolved, such as the neck rupture process during fission. Particle emission near the scission stage provides valuable insights into this process. This work discusses recent experimental results from the BARC-TIFR Pelletron LINAC Facility (PLF) at Mumbai on heavy-ion induced fission using charged particle emissions. Fission and fission like processes have direct relevance to research pertaining to super heavy elements synthesis. Fission process also facilitates study about a fundamental property of finite nuclear matter; nuclear viscosity. Several questions about the nuclear viscosity are still unanswered. Particle emission during the fission process presents a potential probe to study entire fission process and nuclear viscosity. Recent observations on some novel aspects about nuclear scission from our ongoing program at PLF are presented here.

尽管核物理学取得了长足的进步，但某些微妙的方面仍未得到解决，例如裂变过程中的颈破裂过程。在裂解阶段附近的粒子发射为这一过程提供了有价值的见解。本文讨论了位于孟买的BARC-TIFR Pelletron LINAC设施（PLF）利用带电粒子发射进行重离子诱导裂变的最新实验结果。裂变和类裂变过程与超重元素合成的研究直接相关。裂变过程还有助于研究有限核物质的基本性质；核粘度。关于核粘度的几个问题仍然没有答案。裂变过程中的粒子发射为研究整个裂变过程和核粘度提供了一个潜在的探针。我们在PLF正在进行的项目最近对核分裂的一些新方面的观察在这里提出。

引用次数: 0

The role of nuclear symmetry energy and neutron skin thickness of 208Pb in controlling the underlying physics of neutron star 核对称能和208Pb的中子蒙皮厚度在中子星基础物理控制中的作用

IF 2.5 4区物理与天体物理 Q2 PHYSICS, NUCLEAR

Nuclear Physics A

Pub Date : 2025-12-17 DOI: 10.1016/j.nuclphysa.2025.123307

Queena, Mukul Kumar, Sunil Kumar, Raj K. Jagota, Shashi K. Dhiman

The nuclear symmetry energy is fundamental in nuclear astrophysics, influencing phenomena from nuclear structure to gravitational collapse and neutron star formation. Both the symmetry energy and its linear density dependence (L), are critical inputs for numerous nuclear physics and astrophysics applications, as they play a key role in determining properties such as neutron skin thickness (Δr_np) and neutron star radius. Recent results from parity-violating electron scattering experiments on ²⁰⁸Pb (PREX-II: The Lead Radius Experiment)) have offered new insights into these fields. Specifically, the PREX-II experiment has provided a neutron skin thickness for ²⁰⁸Pb of

Δ r_{n p} = 0.283 \pm 0.071

fm. This measurement helps to constrain the nuclear symmetry energy in laboratory environments. In this study, we propose several interactions (SRQs) based on relativistic energy density functionals that correspond to different values of Δr_np for ²⁰⁸Pb, as derived from the PREX-II limits. We observe a correlation between Δr_np of ²⁰⁸Pb and L. We compute the equations of state for nucleonic matter under β - equilibrium conditions for proposed interactions. We also discuss in detail the effects of Δr_np and L on nuclear matter and neutron star properties. Additionally, these interactions are utilized to explore the characteristics of rotating neutron stars.

核对称能是核天体物理学的基础，影响着从核结构到引力坍缩和中子星形成的各种现象。对称能和它的线性密度依赖关系(L)都是许多核物理和天体物理应用的关键输入，因为它们在确定中子表皮厚度（Δrnp）和中子星半径等特性方面起着关键作用。最近在208Pb上进行的违反宇称的电子散射实验（PREX-II：铅半径实验）的结果为这些领域提供了新的见解。具体来说，PREX-II实验为208Pb提供了Δrnp=0.283±0.071 fm的中子皮厚。这种测量有助于约束实验环境下的核对称能。在这项研究中，我们提出了几种基于相对论能量密度泛函的相互作用（srq），它们对应于208Pb的不同值Δrnp，这些值来自PREX-II极限。我们观察到208Pb和l的Δrnp之间存在相关性。我们在β -平衡条件下计算了核物质的状态方程。我们还详细讨论了Δrnp和L对核物质和中子星性质的影响。此外，这些相互作用被用来探索旋转中子星的特性。

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引用次数: 0

Bohr-Mottelson Hamiltonian with octic potential applied to the 106−116Cd isotopes 带光势的玻尔-莫特尔森哈密顿量应用于106−116Cd同位素

IF 2.5 4区物理与天体物理 Q2 PHYSICS, NUCLEAR

Nuclear Physics A

Pub Date : 2025-12-16 DOI: 10.1016/j.nuclphysa.2025.123311

P. Buganu , R. Budaca

The Bohr-Mottelson Hamiltonian, with an octic potential in the β deformation variable, is numerically solved for a γ-unstable symmetry of the nuclear system. The analytical structure of the model allows the description of multiple phenomena of great interest for the nuclear structure such as ground-state shape phase transitions and their critical points, dynamical shape phase transitions, shape coexistence with and without mixing, anomalous in-band E2 transitions, large E2 intra-band transitions and large monopole transition between the first excited

0^{+}

state and the ground state, respectively. As a first application of the present model is selected the

^{106 - 116}

Cd isotopic chain known in literature to manifest shape phase transition, respectively shape coexistence and mixing.

对核系统的γ-不稳定对称性的Bohr-Mottelson哈密顿量进行了数值求解。该模型的解析结构允许描述对核结构非常感兴趣的多种现象，如基态形状相变及其临界点、动态形状相变、混合和不混合的形状共存、带内异常E2相变、带内大E2相变以及第一激发态与基态之间的大单极子相变。作为本模型的第一个应用，选择了文献中已知的106−116Cd同位素链，分别表现为形状相变，形状共存和混合。

引用次数: 0

Cross-section measurement of 181Ta(n,γ)182Ta with covariance analysis 181Ta(n,γ)182Ta的横截面测量与协方差分析

IF 2.5 4区物理与天体物理 Q2 PHYSICS, NUCLEAR

Nuclear Physics A

Pub Date : 2025-12-16 DOI: 10.1016/j.nuclphysa.2025.123312

Mahima Upadhyay , Punit Dubey , Mahesh Choudhary , Namrata Singh , Shweta Singh , Sriya Paul , G. Mishra , G. Mohanto , Sukanya De , L.S. Danu , B. Lalremruata , Yu N. Kopatch , I.N. Ruskov , Ajay Kumar , R.G. Thomas , A. Kumar

The current study presents the cross-section measurement of ¹⁸¹Ta(n,γ)¹⁸²Ta reaction at 1.37  ±  0.13, 2.06  ±  0.14, 2.56  ±  0.15, and 3.05  ±  0.17 MeV neutron energies utilizing offline γ-ray spectroscopy. The neutrons were generated through the ⁷Li(p,n)⁷Be reaction. The ¹¹⁵In(n,n’γ)^115mIn reaction served as a monitor reaction. The present study provides detailed information on the propagation of uncertainty in the overall result. The required corrections for low energy background neutron and γ-ray coincidence summing effect have been made in the present measurement. The output is compared with the pre-existing cross-section data from the EXFOR database, evaluated data libraries and theoretical model predictions like level density models and γ-ray strength functions.

本研究利用脱机γ射线能谱法测量了181Ta(n,γ)182Ta反应在1.37 ± 0.13,2.06 ± 0.14,2.56 ± 0.15和3.05 ± 0.17 MeV中子能量下的截面。中子是通过7Li(p,n)7Be反应产生的。115In(n,n′γ)115mIn反应作为监测反应。本研究提供了总体结果中不确定性传播的详细信息。对低能背景中子和γ射线的重合和效应进行了必要的修正。输出结果与EXFOR数据库中已有的截面数据、评估数据库和理论模型预测（如水平密度模型和γ射线强度函数）进行比较。

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引用次数: 0

Collective enhancement in nuclear level density and shape transitions in 169Tm 169Tm中核能级密度和形状转变的集体增强

IF 2.5 4区物理与天体物理 Q2 PHYSICS, NUCLEAR

Nuclear Physics A

Pub Date : 2025-12-16 DOI: 10.1016/j.nuclphysa.2025.123309

V. Parvathi, A. K. Rhine Kumar

Collective enhancement in nuclear level density (CELD) is a key phenomenon in the calculation of nuclear level density (NLD) arising from the coupling of intrinsic excitations with collective rotational and vibrational modes. This effect is especially pronounced in well-deformed nuclei, where rotational motion significantly increases the density of states at low excitation energies. However, increasing excitation energy leads to a gradual fadeout of this enhancement. In this study, we investigate CELD and its fadeout in the ¹⁶⁹Tm nucleus, using the Finite-Temperature BCS (FTBCS) approach to calculate the intrinsic level density and incorporating rotational effects through a deformation-dependent enhancement factor. By examining free energy surfaces and shape transitions across different excitation energies and angular momenta, we aim to investigate the relationship between nuclear deformation and the emergence or suppression of collective effects. The results provide a comprehensive understanding of how shape evolution influences CELD behaviour in excited nuclear systems. However, the theoretically predicted fadeout energy is significantly higher than the experimentally observed value.

核能级密度集体增强（CELD）是计算核能级密度（NLD）的一个关键现象，它是由于本征激励与集体旋转和振动模式的耦合而产生的。这种效应在形变良好的原子核中尤其明显，在那里旋转运动显著地增加了低激发能态的密度。然而，增加激发能导致这种增强逐渐消退。在这项研究中，我们使用有限温度BCS （FTBCS）方法来计算内在能级密度，并通过变形相关的增强因子纳入旋转效应，研究了169Tm核中的CELD及其衰减。通过考察不同激发能和角动量下的自由能表面和形状转变，我们旨在研究核变形与集体效应的产生或抑制之间的关系。结果提供了一个全面的理解如何形状演变影响CELD行为在激发核系统。然而，理论预测的衰减能量明显高于实验观测值。

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引用次数: 0

Optimizing electron bunch characteristics through longitudinal density tailoring in laser wakefield acceleration 激光尾流场加速中纵向密度裁剪优化电子束特性

IF 2.5 4区物理与天体物理 Q2 PHYSICS, NUCLEAR

Nuclear Physics A

Pub Date : 2025-12-13 DOI: 10.1016/j.nuclphysa.2025.123308

Ravina, Devki Nandan Gupta

We investigate advanced electron acceleration in the laser wakefield acceleration (LWFA) regime by exploiting longitudinally tailored plasma density profiles. By engineering the plasma density along the propagation direction, we demonstrate the enhanced control over the injection dynamics and subsequent acceleration of electron bunches. Using a parabolic longitudinal density profile, we show that both the energy and quality of the accelerated electron beams–characterized by energy spread and emittance can be significantly optimized. The study reveals a powerful synergy between the longitudinal plasma density gradient and electron bunch properties, enabling beam characteristics suitable for high-precision applications. Our results provide a practical pathway for designing plasma channels that maximize energy gain while maintaining beam quality, offering new strategies for next-generation compact electron accelerators.

我们通过利用纵向定制等离子体密度分布来研究激光尾流场加速（LWFA）机制中的高级电子加速。通过设计等离子体密度沿传播方向，我们证明了对注入动力学和随后的电子束加速的增强控制。利用抛物线纵向密度曲线，我们发现加速电子束的能量和质量——以能量扩散和发射度为特征——都可以得到显著优化。该研究揭示了纵向等离子体密度梯度和电子束特性之间的强大协同作用，使光束特性适合高精度应用。我们的研究结果为等离子体通道的设计提供了一条实用的途径，使能量增益最大化，同时保持束流质量，为下一代紧凑型电子加速器提供了新的策略。

引用次数: 0

Corrigendum to “Macroscopic-microscopic analysis of deformation energy, Q20 electric quadrupole moments, and equilibrium shapes in even-even barium and cerium isotopes” [Nuclear Physics A, Volume 1062, 2025, 123172] “变形能的宏观-微观分析，Q20电四极矩，平衡形状在偶数钡和铈同位素”的勘误表[核物理学A卷1062,2025,123172]

IF 2.5 4区物理与天体物理 Q2 PHYSICS, NUCLEAR

Nuclear Physics A

Pub Date : 2025-12-08 DOI: 10.1016/j.nuclphysa.2025.123304

Hadj Mouloudj , Fethi Redjem , Oussama Zeggai , Mousaab Belarbi , Youcef Belgaid , Abdelkader Ghalem

引用次数: 0

Elastic scattering of α-particles from nα-cluster nuclei using the high-energy approximation and São Paulo potential 基于高能近似和<s:1>圣保罗势的nα团簇核α-粒子弹性散射

IF 2.5 4区物理与天体物理 Q2 PHYSICS, NUCLEAR

Nuclear Physics A

Pub Date : 2025-12-04 DOI: 10.1016/j.nuclphysa.2025.123306

Awad A Ibraheem , M.N. El-Hammamy , F. Algahatani , Rehab Yajzey , Sh. Hamada , A. Attia

This work investigates α-particle elastic scattering from nα-cluster nuclei (¹²C - ⁴⁰Ca, n = 3–10) at 240 MeV, 386 MeV, with emphasis on refining the α-nucleus optical potential. The relative wave function of the alpha-cluster is used to derive cluster densities for constructing the High-Energy Approximation (HEA) and São Paulo (SPP) potentials. The excellent agreement between theoretical results and experimental data highlights the strength of these methods in describing α-nucleus interactions and underscores their relevance in nuclear reaction studies.

本文研究了nα-团簇核（12C - 40Ca, n = 3-10）在240 MeV， 386 MeV下α-粒子的弹性散射，重点研究了α-核光势的细化。利用α -簇的相对波函数推导出簇密度，用于构造高能近似（HEA）和圣保罗（SPP）势。理论结果和实验数据之间的良好一致性突出了这些方法在描述α-核相互作用方面的优势，并强调了它们在核反应研究中的相关性。

引用次数: 0

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