Current status of superallowed 0+ ->0+ nuclear β decay and the value of Vud

Currently, the results from superallowed 0⁺ ->0⁺ nuclear β decays provide the most precise value for V_ud, the up-down element of the Cabibbo-Kobayashi-Maskawa (CKM) quark-mixing matrix. According to the most recent critical survey of world data, the ft values for 14 of these superallowed transitions have been established to a precision of order 0.1% or better. These results, which cover a wide range of parent nuclei from ¹⁰C to ⁷⁴Rb, constitute a very robust data set. After radiative and isospin-symmetry-breaking corrections have been applied, the resulting corrected Ft values are all consistent with one another, demonstrating agreement with conservation of the vector current (CVC). With CVC upheld, the Ft -value results can then be averaged to obtain a value for G_V, the vector coupling constant, and for V_ud. Since the last survey closed, new measurements have appeared, which do not significantly change the conclusions in but do reflect constructively on isospin symmetry breaking and on possible scalar currents. Up-to-date outcomes will be presented.