Four-, Six- and Eight-quasiparticle Isomers in $^{174}$Lu

We report on new studies of $^{174}$Lu using a $^{136}$Xe beam from the ATLAS accelerator at Argonne National Laboratory that was incident on targets of natural Lu and enriched (to 47\%) $^ {176}$Lu. The targets were 6 mg/cm$^{2}$ in thickness with 25 mg/cm$^{2}$ of Au backing. The beam was pulsed approximately 1 ns on/825 ns off at energies of 6 MeV per nucleon. The recoils were stopped at the target position in the focus of the Gammasphere spectrometer, comprised for this experiment of 96 Compton-suppressed Ge detectors. Several high-K isomers were discovered in $^{174}$Lu and their structure characterized, including K$^{\pi}$=13$^{+}$ ($\tau$=280 (25) ns), 14$^{-}$ ($\tau$=55 (6) ns), (21$^{+}$) ($\tau$=140 (15) ns) and (26$^{-} $) ($\tau$=350 (28) ns). The 13$^{+}$ isomer was found to decay to both low-K (K$^{\pi}$=0$^{+}$) and high-K (K$^{\pi}$=7$^{+} $) states originating from couplings of the $\pi$ $7/2[404]$ and $\nu$ $7/2[633]$ orbitals. The path via the K$^{\pi}$=0$^{+} $ band cannot be explained through conventional Coriolis mixings and the accidental mixing scenario between the isomer and a nearby collective level was invoked [1]. Details of these measurements will be presented, together with a comparison with predictions from multi-quasiparticle calculations. \\ $[1]$ G.D. Dracoulis et al., submitted to Phys. Rev. Lett. \\