A Combination of Preliminary Electroweak Measurements and Constraints on the Standard Model

This note presents a combination of published and preliminary electroweak results from the four LEP collaborations and the SLD collaboration which were prepared for the 2000 summer conferences. Averages from Z0 resonance results are derived for hadronic and leptonic cross sections, the leptonic forward-backward asymmetries, the tau polarisation asymmetries, the bbbar and ccbar partial widths and forward-backward asymmetries and the qqbar charge asymmetry. Above the Z0 resonance, averages are derived for di-fermion cross sections and asymmetries, W-pair, Z-pair and single-W production cross section, electroweak gauge boson couplings and W mass and decay branching ratios. The major changes with respect to results presented in summer 1999 are final Z0 lineshape results from LEP, updates to the W mass and gauge-boson couplings from LEP, and ALR from SLD. The results are compared with precise electroweak measurements from other experiments. The parameters of the Standard Model are evaluated, first using the combined LEP electroweak measurements, and then using the full set of electroweak results.