The authors present recent CDF measurements of [tau], [tau]°, and [tau]/[tau]° using exclusive B 2![psi]K decays, where B = B+ or B°, [psi] = J/[psi] or [psi](2S), and K = K+, K*(892)°, K{sub S}°, or K*(892)+. The precision of these results is less than 10% and is nearly identical to that previously reported at LEP.

The lifetimes of the B− and {bar B}° mesons are measured using the partially reconstructed semileptonic decays in the CDF experiment.

Two measurements of the lifetime of neutral and charged B mesons in p{bar p} collisions at √s = 1.8 TeV by the CDF experiment are presented. The first relies on the study of exclusive decays of the type B → [psi] K, the second on semileptonic decays of a B meson into a D° or a D. The combined results are [tau](B+) = 1.62 ± 0.09 ps, [tau](B0) = 1.60 ± 0.09 ps and [tau](B+)/[tau](B°) = 1.00 ± 0.07.

The authors present recent CDF measurements of[tau][sup+], [tau][sup 0], and[tau][sup+]/[tau][sup 0] using exclusive B[yields][psi]K decays, where B= B[sup+] or B[sup 0], [psi]= J/[psi] or[psi](2S), and K= K[sup+], K*(892)[sup 0], K[sub S][sup 0], or K*(892)[sup+]. The precision of these results is less than 10% and is nearly identical to that previously reported at LEP.

Data collected with the BABAR detector at the PEP-II asymmetric B Factory at SLAC are used to study the lifetimes of the B° and B mesons. The data sample consists of 7.4 fb−1 collected near the Upsilon(4S) resonance. B° and B mesons are fully reconstructed in several exclusive hadronic decay modes to charm and charmonium final states. The B lifetimes are determined from the flight length difference between the two B mesons which are pair-produced in the Upsilon(4S) decay. The preliminary measurements of the lifetimes are tau{sub B0} = 1.506 " 0.052 (stat) " 0.029 (syst) ps, tau{sub B+} = 1.602 " 0.049 (stat) " 0.035 (syst) ps, and of their ratio is tau{sub B+}/tau{sub B0} = 1.065 " 0.044 (stat) " 0.021 (syst).

A method is presented to simultaneously separate the contributions to a sample of B{sub (s)}° 2!hh{sup {prime}-} decays, where h = [pi] or K, and measure the B meson lifetimes in the sample while correcting for the bias in the lifetime distributions due to the hadronic trigger at the CDF experiment. Using 1 fb−1 of data collected at CDF the B° lifetime is measured as [tau]{sub B°} = 1.558{sub -0.047}{sup +0.050}{sub stat} ± 0.028{sub syst} ps, in agreement with the world average measurement. The B{sub s}° lifetime in the B{sub s}° 2!KK− decay is measured as [tau]{sub B{sub s}° 2!K+K−} = 1.51{sub -0.11}{sup +0.13}{sub stat} ± 0.04{sub syst} ps. No difference is observed between the lifetime and other measurements of the average B{sub s}° lifetime or the lifetime of the light B{sub s}° mass eigenstate determined from B{sub s}° 2!J/[psi][phi] decays. With the assumptions that B{sub s}° 2!K+K− is 100% CP-even and that [tau]{sub B{sub s}°} = [tau]{sub B°} the width difference in the B{sub s}{sup 0} system is determined as [Delta][Lambda]{sup CP}/[Lambda] = 0.03{sub -0.15}{sup +0.17}{sub stat} ± 0.05{sub syst} using the current world average B{sup 0} lifetime. This is consistent with zero and with the current world average measurement.