利用改进的pn-QRPA模型研究等待点原子核的β衰变性质  

β-decay Properties of Waiting-point Nuclei in an Improved pn-QRPA Model

作　　者：郑启宇 倪冬冬 柏栋 任中洲 ZHENG Qiyu;NI Dongdong;BAI Dong;REN Zhongzhou(School of Physics Science and Engineering,Tongji University,Shanghai 200092,China;State Key Laboratory of Lunar and Planetary Sciences,Macao University of Science and Technology,Macao 519020,China;Key Laboratory of Advanced Microstructure Materials,Ministry of Education,Shanghai 200092,China)

机构地区：[1]同济大学物理科学与工程学院,上海200092 [2]澳门科技大学月球与行星科学国家重点实验室,中国澳门519020 [3]先进微结构材料教育部重点实验室,上海200092

出　　处：《原子核物理评论》2021年第4期361-367,共7页Nuclear Physics Review

基　　金：国家自然科学基金资助项目(11975167,12035011,11961141003,1535004,11761161001,12022517,11947211,11905103);国家重点研发计划项目(2018YFA0404403,2016YFE0129300);澳门科技发展基金资助项目(0048/2020/A1,008/2017/AFJ);中央高校基本科研业务费资助项目(22120200101);中国博士后科学基金资助项目(2020T130478,2019M660095)。

摘　　要：r-过程等待点原子核的β衰变半衰期对研究宇宙中重元素起源有重要意义。质子-中子准粒子无规相位近似(pn-QRPA)是研究原子核β衰变的重要理论模型。本工作提出了一个改进的pn-QRPA模型,系统研究了满壳附近原子核的β衰变性质。与之前的工作相比,改进的模型采用了中子数和质子数依赖的新粒子-粒子和粒子-空穴相互作用形式。本工作首先计算了满壳附近一些已知原子核的β衰变半衰期和GamowTeller强度分布,发现理论结果与实验数据符合较好,检验了新模型的可靠性。随后,理论预测了N=50,N=82和N=126附近未知的等待点原子核的β衰变半衰期,如^(124)Mo,^(126)Ru,^(128)Pd,^(186)Nd,^(188)Sm,^(192)Dy,^(194)Er,^(196)Yb,^(198)Hf等,预测结果与之前的模型相近。这些结果对未来满壳层附近的r-过程物理研究有参考价值。β-decay half-lives of r-process waiting-point nuclei are the crucial physical data for understanding the origin of heavy elements in the universe.Proton-neutron quasi-particle random phase approximation(pn-QRPA) is an important theoretical model to study nuclear β decays.In this work,we propose an improved pn-QRPA model to systematically study β decays from nuclei near closed shells.Compared with previous works,new forms of particle-particle and particle-hole interactions are adopted in the improved model,which depend on both the neutron number and the proton number.We first validate our new model by calculating β-decay half-lives and GamowTeller strength distributions of some known nuclei around closed shells.The theoretical results agree well with experimental data.We then predict the β-decay half-lives of various unknown waiting points nuclei near N=50,N=824,and N=126,such as ^(124)Mo,^(126)Ru,^(128)Pd,^(186)Nd,^(188)Sm,^(192)Dy,^(194)Er,^(196)Yb,^(198)Hf.The predic-tions are consistent with the previous model.These results are good references for the future physics research of r-process near the closed shell.

关 键 词：准粒子无规相位近似 r-过程 等待点 β衰变寿命 

分 类 号：O571.53[理学—粒子物理与原子核物理]