A Combination of Preliminary Electroweak Measurements and Constraints on the Standard Model, 2000

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 1999 summer conferences. Averages are derived for hadronic and leptonic cross sections, the leptonic forward-backward asymmetries, the $\tau$ polarisation asymmetries, the $\bb$ and $\cc$ partial widths and forward-backward asymmetries and the $\qq$ charge asymmetry. The major changes with respect to results presented in summer 1998 are updates to the lineshape, W mass and triple-gauge-boson couplings from LEP, and $\cAb$ and $\cAc$ from SLD. The results are compared with precise electroweak measurements from other experiments. A significant update here are new W mass measurements from CDF and D\O. The parameters of the Standard Model are evaluated, first using the combined LEP electroweak measurements, and then using the full set of electroweak results.