Electroweak Working Group Report
D. Bardin, W. Beenakker, M. Bilenky, W. Hollik, M. Martinez, G. Montagna, O. Nicrosini, V. Novikov, L. Okun, A. Olshevsky, G. Passarino, F. Piccinini, S. Riemann, T. Riemann, A. Rozanov, F. Teubert, M. Vysotsky
TL;DR
This report consolidates precision electroweak calculations for Z-resonance observables from LEP1/SLC data by formalizing a common language of effective couplings and comparing multiple independent codes. It details the input parameter set, notably the running electromagnetic coupling at the Z scale, and outlines how pseudo-observables and realistic observables are derived within different renormalization schemes (on-shell, MSbar, Born-like frameworks). The study assesses theoretical uncertainties due to missing higher-order terms, finds small code-to-code differences relative to experimental errors, and emphasizes the need for full two-loop electroweak calculations as data precision improves. It also discusses the structure of radiative corrections, including leading heavy-top and QCD effects, and provides guidance on how to interpret, compare, and combine results across codes for robust MSM tests and new-physics sensitivity.
Abstract
The report summarizes the results of the activities of the Working Group on Precision Calculations for the Z Resonance at CERN during 1994.