Identification of Triaxial Strongly Deformed Bands in $^{164}$Hf

A Gammasphere experiment has been performed at the ATLAS facility to search for triaxial strongly deformed (TSD) bands in $^{164}$Hf through the $^{94}$Zr($^{74}$Ge,4n) reaction. TSD bands, including families of wobbling bands, have been observed in several neighboring Lu and Ta isotopes and in $^{168}$Hf as well. Theoretical studies suggest that the elevated yrast line of $N=92$ isotope $^{164}$Hf may reduce the excitation energy of the predicted TSD structure relative to the normal deformed yrast line. This effect, together with the proton and neutron shell gaps at large triaxiality, makes $^{164}$Hf a better candidate for TSD structures. To date, two candidate TSD bands that are stronger and at lower spins than those in $^{168}$Hf [1] have been identified. Another new band was suggested to be associated with near-prolate shape with an enhanced deformation relative to normal deformed structures, similar to the ED bands systematically observed in heavier Hf isotopes in recent years.\\[4pt] [1] R. B. Yadav {\it et al.}, Phys. Rev. C {\bf 78}, 04316 (2008) and references therein.