Decay of Co-58(m)

We have studied some of the nuclear decay properties of Co-58(m). The half-life is found to be (8.853 +/- 0.023) hours, which is significantly different from the evaluations found in the literature. The absolute intensity of the 24.9-keV gamma ray emitted in the internal transition decay is (0.0387 +/- 0.0016)%, in agreement with the calculated yield of a transition of M3 multipolarity. We observe gamma-ray photons from a previously unreported branch for electron capture decay, with an intensity of (0.00120 +/- 0.00005)%, consistent with expectations from the calculation of log ft.