Measurement of the average lifetime of B hadrons produced in pp¯ collisions at √s =1.8 TeV

The average b-hadron lifetime has been measured using a high statistics sample of B→J/ψ X decays recorded with the Collider Detector at Fermilab. The decay vertices of 5344 inclusive J/ψ→${\mathrm{\mu }}^{+}$${\mathrm{\mu }}^{\mathrm{-}}$ candidates have been reconstructed using information from a silicon vertex detector. The measured B lifetime, which is the average over all b hadrons produced in pp¯ collisions at √s =1.8 TeV weighted by their branching ratios into J/ψ, is 1.46±0.06(stat)±0.06(syst) ps.