The beta decay of ${}_{}{}^{16}{}_{}{}^{}\mathrm{C}$ to ${}_{}{}^{16}{}_{}{}^{}\mathrm{N}$($0^{-}$, 120 keV) has been observed. The branching ratio is (${0.68}_{-0.11\mathrm{}}^{+0.09\mathrm{}}$)% and the $log f_{0}t={6.70}_{-0.05\mathrm{}}^{+0.07\mathrm{}}$. 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 ${}_{}{}^{16}{}_{}{}^{}\mathrm{N}$($1^{-}$, 398 keV).

RADIOACTIVITY ${}_{}{}^{16}{}_{}{}^{}\mathrm{C}$ from ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}(t, p)$: measured $\beta \mathrm{}\left(t\right)\mathrm{}$, $\gamma \mathrm{}\left(t\right)\mathrm{}$, $n\left(t\right)\mathrm{}$; deduced branching ratios; first-forbidden transitions.

• Received 22 November 1982

DOI:https://doi.org/10.1103/PhysRevC.27.1353