Neutral B meson - neutral anti-B meson oscillation in electron-positron collisions at the Z boson resonance
Abstract
The frequency of the particle - anti-particle oscillation is measured in B$\sbsp{\rm d}{0}$ mesons produced in e$\sp+$e$\sp-$ collisions with$\sqrt{s}\approx M\sb{Z\sp0}$ center of mass energy at the L$\sb3$ detector on the Large Electron Positron storage ring of CERN. Semileptonic B decays are selected by requiring at least one lepton with high transverse momentum with respect to the associated jet. The proper time of the B meson decay is measured by reconstructing the production and decay vertices and estimating the B meson momentum with an effective average. Two tagging methods are applied to statistically independent data samples. Charge correlations between two leptons in opposite thrust hemispheres indicate the mixing in the dilepton method. Charge correlations between a lepton and the combined hemisphere (or jet) charge of the two thrust hemispheres are studied in the lepton - jet charge method. The combined result of the two measurements corresponds to a mass difference of$$\Delta m\sb{d}=0.446\pm0.042\ \rm ps\sp{-1}$$between the two $\rm B\sbsp{d}{0}$ mass eigenstates.
Degree
Ph.D.
Advisors
Gutay, Purdue University.
Subject Area
Particle physics
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