核电荷半径的同位旋相关性及其微观诠释  

Isospin Dependence of Nuclear Charge Radii and Its Microscopic Demonstration

作　　者：雷奕安[1] 曾谨言[1] 

机构地区：[1]北京大学物理学院,北京100871

出　　处：《高能物理与核物理》2007年第8期731-735,共5页High Energy Physics and Nuclear Physics

基　　金：国家自然科学基金(10575004;10675006;10435010)资助~~

摘　　要：原子核电荷半径R_c所有的实验数据都表明,R_c系统偏离A^(1/3)律,即随A增大R_c/A^(1/3)系统地递减,而R_c/Z^(1/3)则比较接近于一个常量.原子核巨单极共振能量E_x∝R^(-1)的大量实验数据也支持这一结论.根本原因在于A^(1/3)律与同位旋无关,而Z^(1/3)律已部分反映了同位旋的影响.基于壳模型,给出了Z^(1/3)律的微观诠释.壳模型中质子和中子谐振子势强度参数ω_p和ω_n的差异,可以用Z^(1/3)律说明.基于与Wigner的原子核同位旋多重态质量公式(IMME)相似的理论考虑,提出了核电荷半径改进的Z^(1/3)律.The analysis of experimental nuclear charge radii Rc indicates that Rc deviates systematically from the A^1/3 law, i.e., Rc/A^1/3 gradually decreases with increasing A, whereas Rc/Z^1/3 remains almost a constant. This statement is also supported by the analysis of a large amount of experimental nulcear giant monopole resonance energy data Ex ∝ R^-1. The deviation of nuclear charge radii from the A^1/3 law is basically caused by the isospin independence of A^1/3 law, and the isospin dependence has been partly included in Z^1/3 law. In the frame of nuclear shell model, a microscopic demonstration of the Z^1/3 law is given. The difference in the harmonic oscillator potential strength between proton and neutron （ωp and ωn） can be accounted for by the Z^1/3 law. Similar to Wigner＇s nuclear isobaric multiplet mass equation （IMME）, a modified Z^1/3 law for nuclear charge radii is proposed.

关 键 词：核电荷半径 同位旋相关性 改进的z/1/3律 巨单极共振能量 

分 类 号：O571.21[理学—粒子物理与原子核物理]