Measurement of the B⁰ - B^-0 oscillation frequency using π-B meson charge-flavor correlations in pp collisions at √ s = 1.8 TeV

We present a measurement of the B⁰ ↔ B^-0 oscillation frequency using a flavor tagging method based on correlations of B meson flavor with the charge of other particles produced in pp collisions at √ s = 1.8 TeV. Such correlations are expected to arise from b quark hadronization and from B** decays. We partially reconstruct B mesons using the semileptonic decays B⁰ → l⁺D^(*)-X and B⁺ → l⁺D^-0X. From the oscillation frequency, we obtain the mass difference between the two B⁰ mass eigenstates, Δm_d = 0.471^+0.078 _-0.068(stat) ± 0.034(syst) ħps^-1, and measure the efficiency and purity of this flavor tagging method for both charged and neutral B mesons.