探索四极形变和单粒子共振态在N=28壳闭核^(40)Mg中的作用  

Exploring the role of quadrupole deformation and single-particle resonances in the neutron-rich^(40)Mg at the N=28 shell closure

作　　者：曹雪能 吴雪 何晨 方基宇 周鲜鲜 CAO Xue-Neng;WU Xue;HE Chen;FANG Ji-Yu;ZHOU Xian-Xian(School of Management Science and Engineering,Anhui University of Finance and Economics,Bengbu 233030,China;Department of Mathematics and Physics,Bengbu Medical University,Bengbu 233030,China;School of Mechanics and Optoelectronic Physics,Anhui University of Science and Technology,Huainan 232001,China)

机构地区：[1]安徽财经大学管理科学与工程学院,蚌埠233030 [2]蚌埠医科大学公共基础学院,蚌埠233030 [3]安徽理工大学力学与光电物理学院,淮南232001

出　　处：《中国科学：物理学、力学、天文学》2024年第10期147-156,共10页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家自然科学基金(编号:12205001);安徽财经大学科研计划项目(编号:ACKYC22080)资助。

摘　　要：共振在许多物理现象的形成中起着至关重要的作用.本文首先介绍了单粒子共振态的研究意义和研究方法,其次详细阐述了复动量表象(CMR)方法在研究奇特核方面的优势,最后介绍了极其丰中子核^(40)Mg的研究意义.^(40)Mg的基态表现得像一个单中子晕.为了弄清导致这种晕现象的原因,如大的形变或零势能面附近的共振态等.本文采用CMR方法探讨了^(40)Mg的弱束缚结构,计算了随四极形变演化的束缚态与共振态的能量及宽度.结果显示,p-f轨道反转、幻数N=28消失和一定的形变存在.本文还进一步分析了价中子所占能级主要组分的占比、密度分布和波函数,发现^(40)Mg是一个由p-波配置主导的长椭晕核.这一晕现象可能源自强的四极相关和混合p-f轨道驱动的长椭形变,使得具有低-l组分的单粒子态数量增加.这些发现揭示了弱束缚态或连续谱中的低-l组分轨道有助于晕的形成.本发现对进一步探索更多奇特核中晕特征与形变效应和连续谱耦合之间的关系是必要的.Resonance is critical in the formation of many physical phenomena.Herein,the significance and methods of studying single-particle resonances were introduced.Moreover,the advantages of complex momentum representation(CMR)method in studying exotic nuclei were elaborately provided,and the importance of studying the extremely neutron-rich^(40)Mg was elucidated.Notably,the ground state of^(40)Mg behaves like a one-neutron halo.To understand what causes halo phenomena,such as large deformation or resonances near the zero potential energy surface,we explored the weakly bound structures of^(40)Mg using CMR method.Calculated energies and widths of bound and resonant states show an inversion of the involved p-f orbitals,disappearance of the magic number N=28,and presence of certain deformations.We further analyze the occupation probabilities,density distributions,and wavefunctions of the valence neutron levels,finding that^(40)Mg is a prolate halo nucleus dominated by p-wave configurations.Halo phenomena may result from strong quadrupole correlations and prolate deformations driven by mixed p-f orbitals,leading to an increase in the number of single-particle states with low-l components.These findings reveal that the low-l configuration orbitals in weakly bound states or the continuum contribute to the halo.Our findings are of significant importance for understanding the relationship among halo features,deformation effects,and the coupling of continuum spectra in more exotic nuclei.The mentioned relationship is essential and interesting for future research on exotic phenomena.

关 键 词：四极形变 单粒子共振态 CMR方法 晕 

分 类 号：O571[理学—粒子物理与原子核物理]