Level spacing distribution of scissors mode states in heavy deformed nuclei

We analyse the level spacing distributions of scissors mode states in heavy deformed nuclei. To this end, we use an ensemble of photon scattering data of 13 nuclei. The results are consistent with a Poissonian behaviour which indicates that the correlations between the states are weak only. The significance of this finding is critically investigated. With numerical simulations we study the possible influence of detection thresholds in the photon scattering experiments. A similar analysis of other dipole modes suggests that the collective nature shown for the scissors mode may be a general phenomenon of low-lying states in deformed nuclei. (C) 2000 Elsevier Science B.V. All rights reserved.