Half-lives and branching ratios for the Fermi decays of Ne18, Mg22, Si26, and Ar34 have been studied in experiments which employed a gas-transport system. The ft values for the last two are compared with the mirror decays of Alm26 and Cl34. A difference of (4.6 1.7)% is observed for mass 34 and may be attributable to unexpectedly large charge-dependent mixing. Possible implications are discussed with respect to Cabibbo theory and the existence of an intermediate vector boson. 1972 The American Physical Society.
