The beta decay of C16 to N16(0-, 120 keV) has been observed. The branching ratio is (0.68-0.11+0.09)% and the log f0t=6.70-0.05+0.07. The rate of this 0+0- transition is dominated by the time component of the axial-vector current, which is expected to receive a large enhancement from pion-exchange currents. An upper limit of <0.1% has also been set for the beta-decay branching ratio of N16(1-, 398 keV). RADIOACTIVITY C16 from C14(t, p): measured (t), (t), n(t); deduced branching ratios; first-forbidden transitions. 1983 The American Physical Society.
