Observation of J/Ψ production in multihadronic Z0 decays

Abstract The production of J/ψ mesons in multihadronic Z 0 decays has been observed in the e + e − and β + β − final states. From a sample of approximately 45 reconstructed J ψ mesons, the inclusive branching fraction is measured to be Br(Z 0 →J/ ψ + X) = (4.5±0.8±0.4±0.6) × 10 −3 , where the first error is statistical, the second systematic, and the third error is due to the uncertainty in the leptonic decay rate of the J/ψ. The J/ψ energy distribution is consistent with the distribution expected from B hadron decays. The average B hadron lifetime is calculated from the measured distances between the primary and J/ψ vertices, resulting in τ B = 1.32 −0.25 +0.31 ±0.15 ps, where the first error is statistical and the second systematic.