High-precision half-life determination for the superallowed beta(+) emitter Ga-62

The half-life of the superallowed beta(+) emitter Ga-62 has been measured at TRIUMF's Isotope Separator and Accelerator facility using a fast-tape-transport system and 4 pi continuous-flow gas proportional counter to detect the positrons from the decay of Ga-62 to the daughter Zn-62. The result, T-1/2=116.100 +/- 0.025 ms, represents the most precise measurement to date (0.022%) for any superallowed beta-decay half-life. When combined with six previous measurements of the Ga-62 half-life, a new world average of T-1/2=116.121 +/- 0.021 ms is obtained. This new half-life measurement results in a 20% improvement in the precision of the Ga-62 superallowed ft value while reducing its mean by 0.9 sigma to ft=3074.3(12) s. The impact of this half-life measurement on precision tests of the CVC hypothesis and isospin symmetry breaking corrections for A >= 62 superallowed decays is discussed.