基于实稳定方法的原子核单粒子共振相对论Hartree-Fock模型  

Relativistic Hartree-Fock model of nuclear single-particle resonances based on real stabilization method

作　　者：杨威[1,2] 丁士缘 孙保元 Yang Wei;Ding Shi-Yuan;Sun Bao-Yuan(MOE Frontiers Science Center for Rare Isotopes,Lanzhou University,Lanzhou 730000,China;School of Nuclear Science and Technology,Lanzhou University,Lanzhou 730000,China)

机构地区：[1]兰州大学教育部稀有同位素前沿科学中心,兰州730000 [2]兰州大学核科学与技术学院,兰州730000

出　　处：《物理学报》2024年第6期166-175,共10页Acta Physica Sinica

基　　金：中央高校基本科研业务费专项资金(批准号:lzujbky-2022-sp02,lzujbky-2023-stlt01);国家自然科学基金(批准号:11875152)资助的课题。

摘　　要：利用坐标空间的实稳定方法,在相对论Hartree-Fock(RHF)理论框架下发展了原子核单粒子共振态结构模型.具体以^(120)Sn的低激发中子共振态为例,探讨了交换项在影响共振能量、宽度以及自旋-轨道劈裂等性质中的作用.相较于一般的相对论平均场(RMF)理论,RHF中交换项的引入改变了核介质中有效核力的动力学平衡机制,进而影响共振态单粒子势的描述.对于一般的宽共振态,这可能导致相对更低的共振能量和更小的共振宽度.此外,对^(120)Sn共振态中νi_(13/2)与νi_(11/2)自旋伙伴态,还分析了交换项对其自旋-轨道劈裂的相关效应.与束缚态情形相比,共振态中自旋伙伴态的波函数可能存在显著区别,单粒子有效势与能量也相应发生改变.结果表明,不仅自旋-轨道相互作用,单粒子有效势中其他成分也是影响共振态自旋-轨道劈裂的重要因素.With the development of radioactive ion beam devices along with associated nuclear experimental detection technologies,the research areas in atomic nuclei have been further expanded,illustrating many new aspects of nuclear excitation as well as the physics of exotic nuclei far from theβ-stability line.For weakly bound nuclei,the Fermi surface may lie near the continuum,which facilitates the easy scattering of valence nucleons into the continuum to occupy the resonance state.These continuum effects are of crucial importance in explaining the unusual structure of unstable nuclei.In this work,with the real stabilization method in coordinate space,nuclear structure model for single-particle resonances is developed within the framework of the relativistic Hartree-Fock(RHF)theory.In order to extract potential single-particle resonance structures,we study the evolution of single-particle states with box size in the continuum.To avoid the instability of nuclear binding energy,the pairing correlations are not taken into account in the calculation.As an important motivation,the roles of Fock terms in determining the energy,widths and spin-orbit splitting are discussed for low-lying neutron resonance states of^(120)Sn.By comparing with the relativistic mean field(RMF)model,it is found that the inclusion of exchange terms in the RHF model changes the in-medium balance of nuclear interactions and the equilibrium of nuclear dynamics,which in turn affects the description of the single-particle effective potential.For several neutron resonance states in^(120)Sn with finite resonant width,RHF model predicts lower resonant energy and smaller widths than RMF.For the single-particle states around the continuum threshold,the featured signals of resonance can depend sensitively on the effective interactions.In addition,for the spin-partner statesνi_(13/2)andνi_(11/2)in resonance states,the effect of Fock terms on their spin-orbit splitting is analyzed.In comparison with the bound states,the wave functions of resonant spin-partner s

关 键 词：单粒子共振态 实稳定方法 相对论Hartree-Fock理论 自旋-轨道劈裂 

分 类 号：O571[理学—粒子物理与原子核物理]