| Lifetime measurements for B0 and B+ are presented using semileptonic decays of B mesons from 360 pb-1 of data collected by CDF's lepton plus displaced track trigger. The decays B → ℓnuDX, where D is either D +, D0, or D* +, are partially reconstructed from a muon or electron, a displaced track, and a fully reconstructed charm meson. The B 0 and B+ lifetimes are obtained from an unbinned maximum-likelihood fit to the proper decay length distributions. The measured lifetimes are tauB 0 = 1.527 +/- 0.012(stat.) +/- 0.023( syst.)ps and tauB + = 1.629 +/- 0.013(stat.) +/- 0.025( syst.)ps. |
