Statistical Properties of E(5) and X(5) Symmetries
  We study the energy level statistics of the states in E(5) and X(5) transitional dynamical symmetries. The calculated results indicate that the statistics of E(5) symmetry is regular and follows Poisson statistics, while the statistics of X(5) symmetry involves two maxima in the nearest neighbor level spacing distribution $P(s)$ and the $\Delta_{3}$ statistics follows the GOE statistics. It provides an evidence that the X(5) symmetry is at the critical point exhibiting competing degree of freedom. 
Jing Shu, Hong-Bo Jia, Yu-Xin Liu