Preliminary Lifetime Measurement from SELEX

We report the results of a new lifetime measurement from hadroproduction data taken by the SELEX (E781) experiment. Fermilab charged hyperon beam (Σ−, π− and p) at 600 GeV is used to produce charm particles in Cu and diamond targets. This measurement was made using decays into the , , and modes. We used binned maximum likelihood method and 301 ± 31 events yield a lifetime of 430 ± 22 ± 9 fs.