Spin Assignments of Superdeformed Bands in Europium

系统分析了142，143，144，147Eu中的8条超形变带. 在对跃迁能量进行光滑化处理，采用ab拟合或改进的ab拟合，确切地指定了其中7条超形变带的自旋值. 首次指出了147Eu的1，5两带和2，3两带可能都分别构成旋称伙伴带，且均为K=1/2带，脱耦合常数约为-1. 讨论了它们可能的组态结构.A comprehensive investigation of the superdeformed bands observed in 142,143,144,147 Eu was given. The fluctuation in the transition energies has been removed. The smoothed transition energies were fitted by the ab-expression or its modification. The spins of these bands, except for band 4 of 147 Eu, have been assigned conclusively. The exit spin in 143 Eu was proposed to be 29/2, different from that asserted to be determined experimentally but remains to be confirmed. The corresponding values in 142 Eu and 144 Eu(a) are 21 and 28, lower than those proposed in the literature by 6 and 8 units, respectively. Two pairs of superdeformed bands in 147 Eu, i.e. bands 1,5 and bands 2,3 were proposed to be signature partners. The exit spins are 53/2 and 63/2 for the former pair, and 43/2 and 41/2 for the latter pair. In addition, both of them have a rather large de-coupling constant(≈-1),implying they are of K=1/2 and built on the single particle level ν［651］↓ or π［530］↑. This assignment may be helpful for the studies of the so-called identical bands and pseudo-spin problem. The signature partner pairs observed in 144,148 Eu are not included in the investigation.国家自然科学基金中文核心期刊要目总览(PKU)中国科学引文数据库(CSCD)02121-1282