High-precision half-life determination of $^{14}$O via direct $\beta $ counting

The half-life of the superallowed Fermi $\beta ^+$ emitter $^{14}$O was determined to high precision via a direct $\beta $ counting experiment performed at the Isotope Separator and Accelerator (ISAC) facility at TRIUMF. The result, $T_{1/2}$($^{14}$O) = 70619.2(76) ms, is consistent with, but is more precise than, the world average obtained from 11 previous measurements. Combining the $^{14}$O half-life deduced in the present work with the previous most precise measurements of this quantity leads to a reduction in the overall uncertainty, by nearly a factor of 2. The new world average is $T_{1/2}$($^{14}$O) = 70619.6(63) ms with a reduced $\chi ^2$ value of 0.87 obtained from 8 degrees of freedom.