B-lifetime measurements at CDF.

摘要

The average b-hadron lifetime has been measured using a high statistics sample of B (yields) J/(psi)X decays recorded with the Collider Detector at Fermilab. The decay vertices of J/(psi) (yields) (mu)(sup +)(mu)(sup (minus)) 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 (radical)s = 1.8 TeV, weighted by their branching ratios into J/(psi) is: (tau)B = 1.46 (plus minus) 0.06(stat.) (plus minus) 0.06(sys.)ps (preliminary); In addition we used the fully reconstructed final states B(sup (plus minus)) (yields) J/(psi)K(sup (plus minus)) and B(sup 0) (yields) J/(psi)K(sup 0)* to measure the exclusive lifetime of charged and neutral B-mesons. We measure: (tau)(sub B)(sup (plus minus)) = 1.59 (plus minus) 0.27(stat.) (plus minus) 0.17(sys.) ps (preliminary); (tau)(sub B)(sup 0) = 1. 34 (plus minus) 0.31 (stat.) (plus minus) 0.17 (sys.) ps (preliminary); From this we obtain the following result for the lifetime ratio: (tau)(sub B)(sup (plus minus))/(tau) (sub B)(sup 0) = 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.