在IBM2中研究了混合对称态．发现某些较高自旋的混合对称态随着Majorana相互作用很快变化．这个结果改变了传统的关于混合对称态的观点：最大F旋态的能量最低，F旋越小，能量越高．Fmin或Fmin-1的态会成为yrast或yrare态．这些态很难向下衰变，因而很稳定．这个研究的结果表明可能存在一种由于质子和中子自由度的特殊性质而引起的新的同质异能态．
Mixed symmetry states were studied in the framework of theneutron-proton interacting boson model(IBM2). It was found that some of the mixed symmetry states with moderate high spins changed very fast with respect to the Majorana interaction. This changes our traditional picture that the maximum F-spin states are the lowest in energy, the smaller the F-spin, the higher the energy. The minimum F-spin states or the state with F-spin next to minimum may become the yrast or yrare state. These states are difficult to decay and become very stable. This study suggests that a possible new mode of isomers may exists due to the special nature in their proton and neutron degrees of freedom.
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