Precision half-life determination of a mirror β transition: The decay of 31S

The half-life of the mirror \(\beta\) decay of 31S has been measured at the IGISOL facility at the University of Jyvaskyla. The value obtained is \(T_{1/2}(^{31}S)=(2553.4\pm 1.8)\) ms, in agreement with previous measurements, but with a precision that is better by a factor of ten than the literature value previously adopted. When the new result is combined with the QEC value measured recently at JYFLTRAP, a precision of better than \(10^{-3}\) is obtained for the ft value.