Shears mechanism in {sup 109}Cd

Lifetimes of high-spin states in two {delta}I=1 bands and one {delta}I=2 band in {sup 109}Cd have been measured using the Doppler shift attenuation method in an experiment performed using the {sup 96}Zr({sup 18}O,5n) reaction with the GAMMASPHERE array. Experimental total angular momenta and reduced transition strengths for both {delta}I=1 bands were compared with tilted axis cranking (shears mechanism) predictions and the {delta}I=2 band with principal axis cranking predictions, based on configurations involving two proton g{sub 9/2} holes and one or three valence quasineutrons from the h{sub 11/2} and mixed g{sub 7/2}/d{sub 5/2} orbitals. Good overall agreement for angular momentum versus rotational frequency has been observed in each case. The {delta}I=2 band is shown to have a large J{sup (2)}/B(E2) ratio suggestive of antimagnetic rotation. Additionally, both dipole bands show a decreasing trend in B(M1) strength as a function of spin, a feature of the shears mechanism. The experimental results are also compared with a semiclassical model that employs effective interactions between the proton holes and neutrons as an alternate interpretation for the shears mechanism. (c) 2000 The American Physical Society.