Precision Measurement Of The He-6 Half-Life And The Weak Axial Current In Nuclei

Studies of He-6 beta decay along with tritium can play an important role in testing ab initio nuclear wave-function calculations and may allow for fixing low-energy constants in effective-field theories. Here, we present an improved determination of the He-6 half-life to a relative precision of 3 X 10(-4). Our value of 806.89 +/- 0.11(stat-0.19syst)(+0.23) ms resolves a major discrepancy between previous measurements. Calculating the statistical rate function we determined the ft value to be 803.04(-0.23)(+0.26) s. The extracted Gamow-Teller matrix element agrees within a few percent with ab initio calculations.