^(80)Sr核yrast带形状相变的微观sdIBM-2研究

Understanding shape phase transitions in the yrast-bands of ^(80)Sr nuclei from the microscopic sdIBM-2 approach

γ射线能量-自旋曲线分析方法指认:^(80)Sr 核的 yrast 带存在从 U(5)振动基态到 O(6)γ-软转子基态的结构相变;借助微观 sdIBM-2方案和实验单粒子能量值,用了除 K(np)外,完全相同的一组参数成功地再现了它们相应的形状相变.计算结果揭示:^(80)Sr 的 yrast 带从基态起直到24^+态都是集体态,还没有出现回弯.理论分析和计算结果表明:对于有相互作用的中子-质子玻色子两流体,在给定的 g(σ),G(σ),K(σ)下,增大 K(np)意味着增强了核子对反抗Coriolis 力拆对-顺排的能力,势必促成"顺排滞后"现象;并从有序性的角度对形状相变给予理解.

It has been identified that the phase transitions from the U（5） vibrational ground-state to γ- soft rotor one occupy in the yrast-band in ^80 Sr nuclei, according to the γ-ray energy over spin curves, then based on the microscopic sdIBM-2 approach and experimental values on single-particle energies, their phase transitions have been reproduced successfully by a same equal parameters except for K^（np）. The calculated results reveal that all yrast-states up to the 24^＋ state are the collective state, and the back bending does not exist in its yrast-band. Theoretical analysis and calculated results show that for interacting neutron-proton boson fluid bodies with the given, the more K^（np） , the more ability to anti brokenaligning from Coriolis force by nucleon-pair, which will result in ＂Alignment Delay＂. Finally, this phase transition is understood from the point of view of ordered structure in ground states.