Parametrization of the statistical rate function for select superallowed transitions

We present a parametrization of the statistical rate function, f, for 20 superallowed 0(+) -> 0(+) nuclear beta transitions between T = 1 analog states, and for 18 superallowed mirror transitions between analog T = 1/2 states. All these transitions are of interest in the determination of V-ud. Although most of the transition Q(EC) values have been measured, their precision will undoubtedly be improved in the future. Our parametrization allows a user to easily calculate the corresponding new f value to high precision (+/- 0.01%) without complicated computing.