Superallowed 0+→0+ nuclear β-decays and Cabibbo universality

Recent experimental data have significantly improved the overall consistency of ft values for superallowed 0+ → 0+ nuclear β-decays. All relevant data are collated in this paper and theoretical electromagnetic corrections applied. The resulting corrected Ft values are constant to within two parts in 3000. This constitutes an exacting experimental confirmation of the CVC hypothesis. Statistical tests applied to the data gave no positive indication of any inadequacies in the theoretical corrections. These tests also set a new limit for the Fierz interference constant, bsub(F)<=0.006, which is an order of magnitude smaller than previous determinations. The value of the vector coupling constant of nuclear β-decay, established from these data, is compared with muon and hyperon β-decays as a test of Cabibbo universality. It is shown that universality is achieved under specific conditions on the mass of the neutral vector boson. (Auth.)