Measurement of the B+ and B0 Lifetimes from Semileptonic Decays

Abstract

The lifetimes of B+ and B0 mesons are measured using a sample of 150,000 hadronic Z0 decays collected by the SLD experiment at the SLC between 1993 and 1995. The analysis identifies the semileptonic decays of B mesons and reconstructs the B meson decay length and charge by vertexing the lepton with a partially reconstructed D meson. This new method results in a sample of 634 (584) charged (neutral) decays with high charge purity. The ratio of B+ : B0 decays in the charged (neutral) sample is 3:1 (1:3). A maximum likelihood fit yields t(B+) = 1.61 +0.13 -0.12(stat) +/- 0.07(syst) ps, t(B0) = 1.56 +0.14 -0.13(stat) +/- 0.10(syst) ps, and t(B+)/t(B0) = 1.03 +0.16 -0.14(stat) +/- 0.09(syst).