Scissors states with and without g-bosons in the interacting boson-fermion model for even-odd nuclei in the N = 82–126 shell

Abstract

The M1 excited scissors states for even-odd nuclei in the N = 82–126 shell are studied, with 185W as the example, in the SU(3) limit of the proton-neutron interacting boson-fermion model with sd- and sgd-bosons. The sd-results are recovered as a special case of the sdg-model; the latter model admits two different (SU)(3)⊗U(2) and U(15)⊗U(2)) coupling schemes and the M1-operator in this limit has two pieces (that behave as (11) and (33) SU(3) tensors), unlike one each in the sd-case. The scissors M1-states in the SU(3)⊗U(2) and U(15)⊗U(2) limits are classified and the location of these states and the corresponding B(M1) values are predicted for the SU(3)⊗U(2) limit. The results given for 185W are directly applicable for the nuclei 187, 189Os. Results for other even-odd nuclei in the N = 82–126 shell are also given.