The average b-hadron lifetime has been measured using a high statistics sample of[ital B][r-arrow][ital J]/[psi][Chi] decays recorded with the Collider Detector at Fermilab. We use a sample with an integrated luminosity of[approx] 90[ital pb][sup -1] recorded during the 1994-95 running period. The decay vertices of[approx] 62656 inclusive[ital J]/[psi][r-arrow][mu][sup+][mu][sup -] candidates have been reconstructed using information from a silicon vertex-detector. The measured[ital B]lifetime, which is the average over all b-hadrons produced in[ital p][ital[anti p]] collisions at[radical]s= 1.8 TeV weighted by their branching ratios into[ital J]/[psi], is 1.524[+-] 0.015 ([ital stat])[sup+0.035][sub -0.026] ([ital sys]) ps. The precision of this measurement is significantly improved compared to the inclusive lifetime measurement published previously using[approx] 10[ital pb][sup -1].

This dissertation describes the measurement of the average B hadron lifetime using a high statistics sample of B--> J/psi X decays produced in proton antiproton collisions at a center of mass energy of 1.8 TeV at the Fermilab Tevatron. The integrated luminosity of the sample is 10.1 pb-1 recorded with the Collider Detector at Fermilab (CDF). In this analysis the decay vertex of the decay J/psi -->mu^+ mu^-$ as reconstructed by a silicon vertex detector is used to extract the lifetime from the data. We find the following value for the average b hadron lifetime: [ tau_{B} = 1.46 pm 0.06; (stat.); pm 0.06; (syst.); ps] This is the first measurement of the b-hadron lifetime at a hadron collider. It demonstrates that it is possible to access the large b-quark production cross section in $poverline{p}$ collisions and to achieve high statistics even in modes which have small product branching ratios as in this case: $BR(Brightarrow J/psi X) cdot BR(J/psi rightarrow mu^+ mu^-) = 7.7 times 10^{-4}$.

During the run period from May 1992 to begin of June 1993 the Collider Detector at Fermilab (CDF) has recorded [approx] 21.4 pb[sup [minus]1] of p[anti p] collider data at [radical]s = 1.8 TeV. For this run the detector had been upgraded which significantly enhanced its b-physics capabilities. The upgrades include a high precision Silicon VerteX detector (SVX) which enables CDF to reconstruct the decay vertex and decay length of b-hadrons. In this article the author reports on several measurements of the lifetime of b-flavored hadrons. The determination of the average b-lifetime using inclusive J/[psi]'s, the measurement of the B[sup [+-]] and B[sup 0] lifetimes by reconstructing exclusive final states including a J/[psi] or [psi](2S) and a measurement of the B[sub s][sup 0] meson lifetime exploiting the decay: B[sub s] [yields] l[nu]D[sub s][sup +] [yields] l[nu][phi][pi][sup +] [yields] l[nu]K[sup +]K[sup [minus]][pi][sup +].

Bottom hadron lifetime measurements have been performed using B → J/[psi] → [mu]+[mu]−X dacays recorded with the collider Detector at Fermilab (CDF) during the first half of the 1992--1993 Tevatron collider run. These decays have been reconstructed in a silicon vertex detector. Using 5344 ± 73 inclusive J/[psi] events, the average lifetime of all bottom hadrons produced in 1.8 TeV p{bar p} collisions and decaying into a J/[psi] events, the average lifetime of all bottom hadrons produced in 1.8 TeV p{bar p} collisions and decaying into a J/[psi] is found to be 1.46 ± 0.06(stat) ±0.06(sys)ps. The charged and neutral B meson lifetimes have been measured separately using 75 ±10 (charged) and 61±9 (neutral) fully reconstructed decays; preliminary results are [tau]{sup ±} = 1.63 ± 0.21(stat) ± 0.16(sys) ± 0. 10(sys) ps, yielding a lifetime ratio of [tau]{sup ±}/[tau]° = 1.06{plus_minus} 0.20(stat){plus_minus}0.12(sys).