Parity-Violating and Normal Multipole Mixing Ratios of the 57-keV Gamma Transition ofHf180

The parity-violating forward-backward asymmetry of the 57-keV $\gamma$ radiation from low-temperature polarized ${}_{}{}^{180m}{}_{}{}^{}\mathrm{Hf}$ has been measured to be -(19.4 ± 9.2) × ${10}^{-4\mathrm{}}$, indicating the lack of any large parity-violating effect for this very strongly hindered $E1\mathrm{}$ transition, in agreement with our calculations. The $\frac{M2\mathrm{}}{E1\mathrm{}}$ and $\frac{E3\mathrm{}}{E1\mathrm{}}$ multipole mixing ratios of the 57-keV transition have been determined to be ${\delta }_1\left(\frac{M2\mathrm{}}{E1\mathrm{}}\right)=-\left({0.009}_{-0.085\mathrm{}}^{+0.065\mathrm{}}\right)$ and ${\delta }_2\left(\frac{E3\mathrm{}}{E1\mathrm{}}\right)=+0.013\mathrm{}\pm 0.020$.