Is there a proton-neutron interacting boson model rule for M1 properties? art. no. 037302

We investigate the robustness of the purported correlation between the g-fa ctor ratios in the gamma and ground bands and the corresponding E2/M1 mixin g ratios in the proton-neutron interacting boson model. We show that this c orrelation is dependent on the choice of the Hamiltonian and can be transgr essed, when the parameters are chosen appropriately. The recent M1 data in Er-168, which do not exhibit such a correlation, are analyzed in the light of these results. [S0556-2813(99)05608-3].