Measurement of Charmed-Particle Lifetimes and Decay Branching Ratios

The lifetimes of charmed hadrons photoproduced in nuclear emulsion have been computed from a practically background-free sample of 44 neutral particle decays and 42 charged-particle decays including 27D ± , 11Λ c + , 1D s + and 3 ambiguous decays. The values obtained are τ(D 0 , 0 ) = (3.6 -0.8 +1.2 ± 0.7) 10 -13 s, τ(D ± ) = (5.0 -1.0 +1.5 ± 1.9) 10 -13 s, τ(Λ c + ) = = (2.3 -0.6 +0.9 ± 0.4) 10 -13 s. Branching ratios of various decay topologies were also obtained.