High-spin level structure in ${}^{184}\mathrm{Au}$ has been reinvestigated using the multidetector array of GASP via the ${}^{159}\mathrm{Tb}\left({}^{29}\mathrm{Si},4\mathrm{n}\gamma \right){}^{184}\mathrm{Au}$ reaction at a beam energy of $140\mathrm{MeV}$. The ground-state band and the excited $\pi i_{13∕2}\otimes \nu i_{13∕2}$ 2-qp band have been extended up to lower and higher spin states. An upbend has been observed in the excited band at $\hslash \omega \sim 0.25\mathrm{MeV}$ and is interpreted as resulting from a pair of $\pi h_{9∕2}$ alignment. This low-frequency ${\left(\pi h_{9∕2}\right)}^2$ alignment is supported by the measured $B\left(M1\right)∕B\left(E2\right)$ ratios and alignment properties in neighboring odd-$A$ nuclei. The linking transitions between the two bands and to the ground state have been established leading to a firm spin-and-parity assignment for the $\pi i_{13∕2}\otimes \nu i_{13∕2}$ band in ${}^{184}\mathrm{Au}$. This result provides strong evidence for the low-spin signature inversion in the $\pi i_{13∕2}\otimes \nu i_{13∕2}$ bands of odd-odd nuclei in the $A\sim 180$ mass region.

• Received 17 July 2004

DOI:https://doi.org/10.1103/PhysRevC.70.057303