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arXiv 2503.08070nucl-th
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76Se的核结构性质与恒星弱过程速率：伽莫夫-泰勒强度的解阻塞

Nuclear Structure Properties and Stellar Weak Rates for 76Se: Unblocking of the Gamow Teller Strength

Jameel-Un Nabi, Mavra Ishfaq, Mahmut Boyukata, Muhammad Riaz

备注：
32 Pages, 5 Tables, 9 Figures
发表信息：
Nuclear Physics A, 966, 1-19 (2017)
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AI总结：

本文利用IBM-1研究76Se核结构，并用形变pn-QRPA模型逐态计算其GT跃迁与恒星弱过程速率，确认GT强度解阻塞，指出高温低密度下β+衰变不可忽略。

摘要：

在有限温度（≥10^7 K）下，76Se在大质量恒星核心中丰度较高，76Se上的电子俘获在核心坍缩动力学中具有重要作用。本工作可分为两个主要部分。在第一阶段，我们利用相互作用玻色子模型-1（IBM-1）研究76Se的核结构性质。IBM-1研究包括能级、B(E2)值以及几何形状的预测。我们进行了扩展一致Q形式（ECQF）计算，随后进行了三轴形式计算（通过在ECQF中加入立方项构建）。76Se的几何形状可以在基于IBM-1模型经典极限的势能面形式框架内加以描述。在第二阶段，我们重新确认了76Se中伽莫夫-泰勒（GT）强度的解阻塞（作为N > 40且Z < 40原子核的一个检验案例）。利用形变pn-QRPA模型，我们计算了76Se的GT跃迁、恒星电子俘获截面（在低动量转移极限内）以及恒星弱过程速率。我们计算的显著特点是以完全微观的方式对恒星弱过程速率进行逐态评估。结果与实验数据及先前计算进行了比较。计算得到的GT分布满足Ikeda求和规则。还计算了β延迟中子速率和发射概率。我们的研究表明，在高等恒星温度和低密度条件下，76Se上的β+衰变不应被忽略，需要与电子俘获速率一并考虑，以用于大质量恒星前超新星演化的模拟。

英文摘要：

At finite temperatures ($\geq 10^7$K), $^{76}$Se is abundant in the core of massive stars and electron capture on $^{76}$Se has a consequential role to play in the dynamics of core collapse. The present work may be classified into two main categories. In the first phase, we study the nuclear structure properties of $^{76}$Se using the interacting boson model-1 (IBM-1). The IBM-1 investigations include the energy levels, $B(E2)$ values, and the prediction of the geometry. We performed the extended consistent-Q formalism (ECQF) calculation and later the triaxial formalism calculation (constructed by adding the cubic term to the ECQF). The geometry of $^{76}$Se can be envisioned within the formalism of the potential energy surface based on the classical limit of the IBM-1 model. In the second phase, we reconfirm the unblocking of the Gamow-Teller (GT) strength in $^{76}$Se (a test case for nuclei having $N > 40$ and $Z < 40$). Using the deformed pn-QRPA model, we calculate GT transitions, stellar electron capture cross section (within the limit of low momentum transfer), and stellar weak rates for $^{76}$Se. The distinguishing feature of our calculation is a state-by-state evaluation of stellar weak rates in a fully microscopic fashion. Results are compared with experimental data and previous calculations. The calculated GT distribution fulfills the Ikeda sum rule. Rates for $β$-delayed neutrons and emission probabilities are also calculated. Our study suggests that at high stellar temperatures and low densities, the $β^+$-decay on $^{76}$Se should not be neglected and needs to be taken into consideration along with electron capture rates for simulation of presupernova evolution of massive stars.

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