The lifetime of positive heavy mesons

Summary  Over two hundred examples of the decay in flight of positive heavy mesons produced at the Bevatron have been observed in the photographic emulsions, and from these the lifetime of the particles has been estimated. The lifetime averaged over all modes of decay is found to be 1.35 −0.13 +0.16 s. The effect of experimental biases is discussed, and the final result is compared with that of other authors.