Search for axion emission in the decay of excited states ofC12

We report on a search for axion emission in the ground-state decay of the $T=1\mathrm{}$, $J^P=1^{+}$ (15.1 MeV) and the $T=0\mathrm{}$, $J^P=1^{+}$ (12.7 MeV) states of ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$. The experiment is sensitive to axions decaying by emission of $e^{+}{e}^{-}$ pairs. We see no evidence for the existence of the axion and our results rule out a range of possible axion masses and mixing angles in the mass region between 1 and 15 MeV.