核力的同位旋对称性破缺及其效应研究进展  

Progress on isospin-symmetry-breaking in nuclear forces and its effects

作　　者：董建敏[1] Jianmin Dong(Institute of Modern Physics,Chinese Academy of Sciences,Lanzhou 730000,China)

机构地区：[1]中国科学院近代物理研究所,兰州730000

出　　处：《科学通报》2024年第14期1857-1865,共9页Chinese Science Bulletin

基　　金：国家自然科学基金(12222511);中国科学院战略性先导科技专项(B类)(XDB34000000)资助。

摘　　要：核力的电荷对称性和电荷无关性被视为核物理的基本准则.然而,核子-核子散射实验已经揭示了核力存在同位旋对称性破缺成分,在核结构研究中受到越来越广泛的关注.本文介绍了近些年国内外在核力的同位旋对称性破缺及其效应方面的研究历程、面临的困难和解决的方法,重点阐述了我们取得的最新研究进展,包括基于微观核多体理论结合裸相互作用提取了核力的同位旋对称性破缺成分对核物质平均单核子能量的影响,并以此构建了电荷对称性破缺和电荷无关性破缺有效两体相互作用;建立了推广的同位旋多重态质量公式,用于解释Nolen-Schiffer反常以及Wigner同位旋多重态质量公式失效的现象;结合电荷对称性破缺有效相互作用和镜像核结合能之差的实验值,对质子间库仑力做了进一步的考虑和修正,并且建立了新的Skyrme相互作用IMP1和IMP2用以探索同位旋对称性破缺相关的问题.同时,同位旋对称性破缺相关的核结构问题也是我国兰州和惠州大科学装置上重点研究的科学问题之一.The charge-symmetry and charge-independence of strong nuclear forces are regarded as fundamental criteria in nuclearphysics. However, the nucleon-nucleon scattering data suggest the charge-violating components of the nuclear force, thatis, neutron-neutron interaction vnn is slightly more attractive than proton-proton strong interaction vpp, and neutron-protoninteraction vnp is stronger than (vnn+vpp)/2. This review introduces the research progress on the isospin-symmetry-breakingcomponent of nuclear forces and its effects, the challenges faced and the methods used to address them. In particular ourrecent work is reviewed. By employing the microscopic theory combined with bare nuclear forces, the effects of chargeviolatingcomponents of the nuclear force on the average single-nucleon energy in nuclear matter are extracted, which arecharacterized by the correspondingly symmetry energy coefficients. With these results as calibrations, we constructedcharge-symmetry-breaking (CSB) and charge-independence-breaking (CIB) effective two-body interactions in the Skyrmeenergy density functional theory. A generalized isobaric multiplet mass equation (GIMME) is established to address theNolen-Schiffer anomaly (theoretically calculated Coulomb displacement energy turns out to be several percents smallerthan the experimental ones persistently over a wide range of nuclei) and the breakdown of the Wigner’s quadratic isobaricmultiplet mass equation (IMME). For the first time, the high-order terms dTz3and eTz4 as well as the specific expressionsfor d and e coefficients for the isobaric quartets and quintets are derived. The CSB interaction in the nuclear medium,combined with the core polarization effect induced by the Coulomb force, is responsible for the breakdown of the quadraticIMME. The magnitude of the calculated d coefficient exhibits an oscillation-like behavior with mass number, modulated bythe shell effect, and the experimental d values extracted from the measured masses agree with the oscillation patternqualitatively. If

关 键 词：同位旋对称性 同位旋对称性破缺 核力 同位旋多重态质量公式 Nolen-Schiffer反常 

分 类 号：O571[理学—粒子物理与原子核物理]