Measurement of e+e- → b bar b forward-backward charge asymmetry

This dissertation describes the measurement of the forward-backward charge symmetry, Ab, for e+e- → b bar b at TRISTAN by the e+e- → b bar b to the theoretical QED cross section for e+e- →μ+μ- is also obtained. Ab is an effect of the weak-electromagnetic interference. The measurement of Ab is therefore is the only e+e- collider in the world to explore the center-of-mass energy region of 50 GeV to 62 GeV, where the effects of weak-electromagnetic interference becomes maximum. T he data were collected between June 1987 and July 1989 with a total integrated luminosity of 33.3 pb-1 and center-of-mass energies ranging from 52 GeV to 61.8 GeV. Multihadronic events with a muon were used for the analysis. The measured values were Ab = -82 ± 0.25 (stat) ± 0.14(syst.) and Rb = 0.47 ± 0.12 ± 0.12 at an average center-of-mass energy of 57.2 GeV. These results were consistent with the standard model electroweak theory predictions of Ab = -0.58 and Rb = 0.56 at this energy. The measurement of the charge asymmetry is used to set on B0-bar B0 of χ < 0.20 at the 90% confidence level