钙同位素中N=32壳层演化：从宏观到微观模型的证据
N = 32 Shell Evolution in Calcium Isotopes: Evidence from Macroscopic to Microscopic Models
- KIIT Deemed to be University（KIIT大学）
- Anchalika Mahavidyalaya Gadia（安查利卡玛哈维迪亚拉加迪亚学院）
- Inter University Accelerator Centre（大学间加速器中心）
机构由 AI 辅助整理，请以论文原文为准。
中文总结 AI 辅助
针对钙同位素N=32子壳层闭合与钾同位素电荷半径测量间的矛盾，本研究用宏观、RMF和壳模型方法分析Ca同位素，证实N=32处结构演化特征，并揭示不同相互作用对子壳层的影响。
中文摘要 AI 辅助
钙中公认的N=32子壳层闭合是核结构向富中子核演化的一个重要基准。近期钾同位素的电荷半径测量[Nat. Phys. 17, 439-443 (2021)]显示，在相同中子数下没有相应的增强稳定性特征。受这一差异的启发，我们利用宏观方法、相对论平均场（RMF）和大规模壳模型方法，在KSHELL框架中使用KB3G、GXPF1A、GXPF1B和FPD6相互作用，研究了从N=22到36的偶偶Ca同位素的结构演化。宏观分析在七个理论框架和NNDC数据下进行评估，揭示了N=32处中子结构的连贯变化，最明显体现在壳隙能量$\Delta E$和三点结合能滤波器中，并得到电荷半径滤波器的佐证。具有NL3*的RMF谱显示出清晰的$\nu2p_{3/2}$-$\nu2p_{1/2}$分离，与此特征一致。KB3G和FPD6重现了N=32处$E(2_1^+)$的增强和$R_{4/2}$的降低，而GXPF1A和GXPF1B给出的N=32特征弱于N=34特征，与实验模式相反，表明两个子壳层对单极相互作用的依赖不同。利用上述四种相互作用获得了形变参数和B(E2)值，与实验结果吻合良好。
英文摘要
The well-established N=32 subshell closure in calcium serves as an important benchmark for nuclear structure evolution toward neutron-rich nuclei. Recent charge-radius measurements of potassium isotopes [Nat. Phys. 17, 439-443 (2021)] reveal no corresponding signature of enhanced stability at the same neutron number. Motivated by this discrepancy, we investigate the structural evolution of even-even Ca isotopes from N=22 to 36 using macroscopic, relativistic mean-field (RMF), and large-scale shell-model approaches, with the KB3G, GXPF1A, GXPF1B, and FPD6 interactions in the KSHELL framework. The macroscopic analysis, evaluated against seven theoretical frameworks and NNDC data, reveals a coherent change in neutron structure at N=32, most clearly in the shell-gap energy $ΔE$ and the three-point binding-energy filter, corroborated by the charge-radius filter. The RMF spectrum with NL3* shows a clear $\nu2p_{3/2}$-$\nu2p_{1/2}$ separation consistent with this signature. KB3G and FPD6 reproduce the N=32 enhancement of $E(2_1^+)$ and reduction of $R_{4/2}$, whereas GXPF1A and GXPF1B give a weaker N=32 signature than N=34 signature, the reverse of the experimental pattern, showing that the two subshells depend differently on the monopole interaction. The deformation parameter and B(E2) values have been obtained with above four interactions and are in good agreement with the experimental results.
