B-lifetime Measurements at CDF.

Book excerpt: The average b-hadron lifetime has been measured using a high statistics sample of B → J/?X decays recorded with the Collider Detector at Fermilab. The decay vertices of J/? →??− 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 p{bar p} collisions at √s = 1.8 TeV, weighted by their branching ratios into J/? is:?B = 1.46 ± 0.06(stat.) ± 0.06(sys.)ps (preliminary); In addition we used the fully reconstructed final states B{sup ±} → J/?K{sup ±} and B° → J/?K°* to measure the exclusive lifetime of charged and neutral B-mesons. We measure:?{sub B}{sup ±} = 1.59 ± 0.27(stat.) ± 0.17(sys.) ps (preliminary);?{sub B}° = 1. 34 ± 0.31 (stat.) {plus_minus} 0.17 (sys.) ps (preliminary); From this we obtain the following result for the lifetime ratio:?{sub B}{sup {plus_minus}}/? {sub B}° = 1.19 {plus_minus} 0.35(stat.) {plus_minus} 0.12(sys.) (preliminary); This represents the first measurements of the b-lifetime at a hadron collider.