Measurement of theB+andB0Lifetimes Using Topological Reconstruction of Inclusive and Semileptonic Decays

The lifetimes of $B^{+}$ and $B^0$ mesons are measured using a sample of 150 000 hadronic $Z^0$ decays collected by the SLD experiment at the SLAC Linear Collider between 1993 and 1995. Two analyses are presented in which the decay length and charge of the B meson are reconstructed. The first method uses a novel topological vertexing technique while the second uses semi-inclusively reconstructed semileptonic decays. The topological analysis yields a sample of 6033 (3665) charged (neutral) vertices with good charge purity, whereas the semileptonic analysis yields a smaller sample of 634 (584) charged (neutral) decays with excellent charge purity. Combining the results from both analyses, we find ${\tau }_{B^{+}}=1.66\mathrm{}\pm 0.06\left(\mathrm{stat}\right)\pm 0.05\left(\mathrm{syst}\right)\mathrm{p}\mathrm{s},$ ${\tau }_{B^0}=1.64\mathrm{}\pm 0.08\left(\mathrm{stat}\right)\pm 0.08\left(\mathrm{syst}\right)\mathrm{p}\mathrm{s},$ and ${\tau }_{B^{+}}/{\tau }_{B^0}=1.01\mathrm{}\pm 0.07\left(\mathrm{stat}\right)\pm 0.06\left(\mathrm{syst}\right)$.