弱形变双奇核^(158)Tm中的旋称反转  

Signature Inversion in Weakly-Deformed Doubly-Odd ^(158)Tm

作　　者：周文平[1] 马英君[1] 陆景彬[1] 赵广义[1] 王守宇[1] 孙亮[1] 杨东[1] 赵延新[1] 李险峰[1] 刘运祚[1] 竺礼华[2] 吴晓光[2] 崔兴柱[2] 贺创业[2] 李明非[3] 

机构地区：[1]吉林大学物理学院,长春130021 [2]中国原子能科学研究院,北京102413 [3]东北师范大学物理学院,长春130024

出　　处：《高能物理与核物理》2006年第10期988-995,共8页High Energy Physics and Nuclear Physics

基　　金：国家自然科学基金(10205006);国家重点基础研究发展规划项目(G2000077400)资助~~

摘　　要：通过融合蒸发反应144Nd(19F,5n)布居了双奇核158Tm的高自旋态．扩展了原来已知的带结构,并建立了一条新转动带．通过与相邻核的比较,讨论158Tm核中两条四准粒子带的内禀组态,并分别指定为πh11／2vh9／2(α=+1／2)(vi1312)2和πh／2vh9／2(α=-1／2)(vi13／2)2组态．建立在πh11／2vi13／2组态上的转动带被观测到呈现持续旋称反转现象,而前述的两条高自旋区的四准粒子转动带也呈旋称反转．对这两种类型的旋称反转现象的可能机制进行了简单而定性的讨论．High-spin states in ^158 Tm were populated via the ^144 Nd（^19 F, 5n） fusion-evaporation reaction at beam energies of 108 and ll2MeV. The previously known level structures have been extended and a new band structure has been identified. In addition, a previously identified four-quasiparticle band has been firmly connected to lower known states. This four-quasiparticle band is assigned to the πh11/2×νh9/2（α=-1/2）×（νi13/2）^2 configuration and thus form a pair of signature partners with another four-quasiparticle band known as being built on the πh11/2×νh9/2（α=-1/2）×（νi13/2）^2 configuration. The band based on the πh11/2×νi13/2 configuration is observed to show anomalous signature splitting persistently, across the spin where a restoration to normal signature splitting is expected from systematics. Signature inversion is also established in the doublet πh11/2×νh9/2×（νi13/2）^2 bands. Positive triaxial deformation is supposed to play an important role in the occurrence of the unusual signature inversions in the weakly-deformed doubly-odd nucleus ^158 Tm.

关 键 词：旋称反转 双奇核 带结构 组态指定 高自旋态 

分 类 号：O571.2[理学—粒子物理与原子核物理]