6533b870fe1ef96bd12cefd4

RESEARCH PRODUCT

Shears mechanism in109Cd

subject

description

Lifetimes of high-spin states in two $\ensuremath{\Delta}I=1$ bands and one $\ensuremath{\Delta}I=2$ band in ${}^{109}\mathrm{Cd}$ have been measured using the Doppler shift attenuation method in an experiment performed using the ${}^{96}\mathrm{Zr}{(}^{18}\mathrm{O},5n)$ reaction with the GAMMASPHERE array. Experimental total angular momenta and reduced transition strengths for both $\ensuremath{\Delta}I=1$ bands were compared with tilted axis cranking (shears mechanism) predictions and the $\ensuremath{\Delta}I=2$ band with principal axis cranking predictions, based on configurations involving two proton ${g}_{9/2}$ holes and one or three valence quasineutrons from the ${h}_{11/2}$ and mixed ${g}_{7/2}{/d}_{5/2}$ orbitals. Good overall agreement for angular momentum versus rotational frequency has been observed in each case. The $\ensuremath{\Delta}I=2$ band is shown to have a large ${\mathcal{J}}^{(2)}/B(E2)$ 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.