Exclusive decay study of the 16.62\,MeV (2$^-$, T=1) resonance in $^{12}$C

Abstract

The 3$\alpha$ decay of the 16.62\,MeV (2$^-$, T=1) resonance in $^{12}$C has been studied for nearly a century starting with one of the first nuclear reaction studies at the Cavendish Laboratory in the 1930s. In the hitherto latest study published a decade ago a model based on earlier work from the 1960s was found to give a good account of a set of inclusive data. This model describes the decay as an l=3 $\alpha$-particle populating the 2$^+$ state of $^8$Be. Here we provide new exclusive data on the 3$\alpha$ decay of the 16.62\,MeV resonance, and demonstrate that the decay is best described by a model with predominantly l=1 emission with an admixture of l=3.