A study of the nucleus ${}^{106}\mathrm{Ag}$ has revealed the presence of two strongly coupled negative-parity rotational bands up to the ${19}^{-}$ and ${20}^{-}$ states, respectively, which cross each other at spin $I\sim 14$. The data suggest that near the crossover point the bands correspond to different shapes, which is different to the behavior expected from a pair of chiral bands. Inspection of the properties of these bands indicates a triaxial and a planar nature of rotation for the two structures. Possible causes for this may be understood in terms of a shape transformation resulting from the large degree of $\gamma$ softness of ${}^{106}\mathrm{Ag}$. These data, along with the systematics of the odd-odd structures in the mass 100 region, suggest that $\gamma$ softness has marked implications for the phenomenon of nuclear chirality.

• Received 26 September 2006

DOI:https://doi.org/10.1103/PhysRevLett.98.102501