K-hindered decay of a six-quasiparticle isomer in (176)Hf

The structure and decay properties of high-K isomers in {sup 176}Hf have been studied using beam sweeping techniques and the Gammasphere multidetector array. A new {Delta}K = 8 decay branch, from a K{sup {pi}} = 22{sup -}, six-quasiparticle, isomeric (t{sub 1/2} = 43 {micro}s) state at 4864 keV to the 20{sup -} state of a K{sup {pi}} = 14{sup -} band, has been identified. The reduced hindrance factor per degree of K forbiddenness for this decay is measured to be unusually low (f{sub ?} = 3.2), which suggests K mixing in the states involved. The deduced interaction matrix elements are discussed within the context of relevant K-mixing scenarios. The 3266-keV state, previously interpreted as a K{sup {pi}} = 16{sup +} intrinsic state, is reassigned as the J{sup {pi}} = 16{sup +} member of the band based on the K{sup {pi}} = 15{sup +} state at 3080 keV. The systematics of f{sub ?} values as a function of the degree of forbiddenness is discussed in light of this change.