Measurement of the B^- and B⁻⁰ meson lifetimes using semileptonic decays

The lifetimes of the B^- and B⁻⁰ mesons are measured using the partially reconstructed semileptonic decays B⁻→D1-v⁻X, where D is either a D⁰ or D^*+ meson. The data were collected by the CDF detector at the Fermilab Tevatron collider during 1992-1993 and correspond to 19.3 pb⁻¹ of p⁻p collisions at s = 1.8 TeV. We measure the decay length distributions and find the lifetimes to be τ(B⁻) = 1.56±0.13±0.06 ps and τ(B⁻⁰) = 1.54±0.08±0.06 ps, and the ratio of lifetimes to be τ(B⁻)/τ(B⁻⁰) = 1.01±0.11±0.02, where the first uncertainties are statistical and the second are systematic.