Parameterization of the statistical rate function for select superallowed transitions

We present a parameterization of the statistical rate function, f, for 20 superallowed 0±to-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 future. Our parameterization allows a user to easily calculate the corresponding new f value to high precision (+/-0.01%) without complicated computing.