ΔT = 1, 0+ → 0+ beta decay of 28Mg

The isospin-forbidden beta-decay branching ratio of the 0+, T = 2 28Mg ground state to the 972-keV 0+, T = 1 level of 28Al is measured to be (0.31 +- 0.04) % corresponding to ft = (9.20 +- 1.1) x 107, logft = 7.96 +- 0.06. A charge-dependent matrix element between the 0+, T = 2 analog state at 5992 keV in 28Al 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