Recoil-distance Doppler-shift lifetime measurement of low-lying superdeformed states in194Hg

The lifetimes of three low-lying states in the superdeformed (SD) yrast band of ${}^{194}$Hg were measured applying the recoil-distance Doppler-shift method. As the deduced transition quadrupole moments $Q_t$ are equal within the experimental uncertainties to those extracted from a Doppler-shift attenuation method (DSAM) measurement for the high-lying states of the band, the assumption that the decay out of SD bands does not strongly affect the structure of the corresponding states is corroborated. By a simple mixing model, the decay can be described assuming a very small admixture of normal-deformed (ND) states to the decaying SD states. The deduced ND mixing amplitudes for the yrast SD bands in ${}^{192,194}$Hg and ${}^{194}$Pb are presented along with average transition quadrupole moments for the lower parts of the excited SD bands in ${}^{194}$Hg.