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

TL;DR

This paper combines electroweak measurements from LEP and SLD collaborations to refine Standard Model parameters, update results, and explore phenomena like photon-Z interference and W-pair correlations, providing comprehensive constraints on the model.

Contribution

It presents the first combined analysis of various electroweak measurements, including new results and correlations, to improve Standard Model parameter constraints.

Findings

Updated Z-pole heavy flavour results from SLD and LEP.

New combination of results above the Z pole.

Analysis of photon-Z interference and W-pair correlations.

Abstract

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 2002 summer conferences. Averages from Z resonance results are derived for hadronic and leptonic cross sections, the leptonic forward-backward asymmetries, the tau polarisation asymmetries, the b-bbar and c-cbar partial widths and forward-backward asymmetries and the q-qbar charge asymmetry. Above the Z resonance, averages are derived for di-fermion cross sections and forward-backward asymmetries, photon-pair, W-pair, Z-pair, single-W and single-Z cross sections, electroweak gauge boson couplings, W mass and width and W decay branching ratios. The main changes with respect to the experimental results presented in summer 2001 are updates to the Z-pole heavy flavour results from SLD and LEP, and new combinations of results above the Z pole. A new investigation of the interference of photon and Z-boson exchange is presented. For the first time, colour reconnection and Bose-Einstein correlation analyses in W-pair production are combined. The results are compared with precise electroweak measurements from other experiments, notably the recent final result on the electroweak mixing angle determined in neutrino-nucleon scattering by the NuTeV collaboration. The parameters of the Standard Model are evaluated, first using the combined LEP electroweak measurements, and then using the full set of electroweak results.