论文标题
基于壳模的基于富含中子核的直接捕获的研究
Shell-model based study of the direct capture in neutron-rich nuclei
论文作者
论文摘要
天体物理兴趣同位素的辐射性中子捕获率通常在统计的Hauser-Feshbach反应模型中计算出来。假设化合物系统中的高水平密度可以在光和富含中子的核中质疑这种方法，只有少数或没有共鸣状态可用。因此，在这项工作中，我们关注直接中子捕获过程。我们在具有良好建立有效相互作用的几个模型空间中采用了壳模型方法，以计算不同质量区域的一组50个中子型靶核（包括双重，半魔术和变形的）中的光谱和光谱因子。这些理论能量和光谱因子用于评估直接中子捕获率，并使用基于Hartree-fock-Bogoliubov和组合方法的平均光谱因子和水平密度测试全球理论模型。壳模型和全球模型结果的比较揭示了几种可能与水平密度问题有关的差异。然而，所有结果表明，与依从默认的Hauser-feshbach预测相对于最重要的中子核，直接捕获不可忽略不计，甚至可能比中子滴水线接近最重要的核。
The radiative neutron capture rates for isotopes of astrophysical interest are commonly calculated within the statistical Hauser-Feshbach reaction model. Such an approach, assuming a high level density in the compound system, can be questioned in light and neutron-rich nuclei for which only a few or no resonant states are available. Therefore, in this work we focus on the direct neutron-capture process. We employ a shell-model approach in several model spaces with well-established effective interactions to calculate spectra and spectroscopic factors in a set of 50 neutron-rich target nuclei in different mass regions, including doubly-, semi-magic and deformed ones. Those theoretical energies and spectroscopic factors are used to evaluate direct neutron capture rates and to test global theoretical models using average spectroscopic factors and level densities based on the Hartree-Fock-Bogoliubov plus combinatorial method. The comparison of shell-model and global model results reveals several discrepancies that can be related to problems in level densities. All the results show however that the direct capture is non-negligible with respect to the by-default Hauser-Feshbach predictions and can be even 100 times more important for the most neutron-rich nuclei close to the neutron drip line.
