DELTA-TAU=1,0+-]0+ BETA-DECAY OF MG-28

The isospin-forbidden beta-decay branching ratio of the 0+, T=2 Mg28 ground state to the 972-keV 0+, T=1 level of Al28 is measured to be (0.31 ± 0.04)% corresponding to ft=(9.20±1.1)×107s, logft=7.96±0.06. A charge-dependent matrix element between the 0+, T=2 analog state at 5992 keV in Al28 and the anti-analog level at 972 keV of 20.6 ± 1.6 keV is deduced from this branching ratio. This is in good agreement with a previous result. RADIOACTIVITY Mg28 [from Mg26(t,p)]; measured - coin; deduced branching ratio to A128(0.972), logft, isospin mixing matrix element. Magnetic spectrometer, NaI(T1) detector. © 1979 The American Physical Society.