Mean lifetimes of V-particles and heavy mesons

A maximum-likelihood procedure for determining mean lifetimes of V-particles from cloud-chamber data is applied to samples taken from a group of 134 neutral V-particle decays. For 74 events which were consistent with a decay into a proton and a negative π-meson, a lifetime of (2.5±0.7)×10-10 sec is obtained. Dividing the data into "low Q" and "high Q" groups on the basis of the calculated energy release in the decay, a value of τL=(2.9±0.8)×10-10 sec is found for those cases with 0<~Q<~50 Mev and a value of τH=(1.6±0.5)×10-10 sec is found for those cases with 50