Evidence for the statistical and sequential nature of O16 breakup into four alphas

The relation between the folding angle distributions observed in the decay of O16 into four alphas and the final alpha-alpha interactions is discussed and inferred from model calculations. Likewise, the excitation energy dependence of the four-alpha decay channel probability is studied. A lack of alpha-alpha interactions is deduced from the analysis and the observed energy dependence is found to be characteristic of a statistical decay. This reveals the statistical nature of the disassembly and suggests a sequential breakup as the decay method.