The ratio R of hadronic and electronic Z widths and the strong coupling constants αs

Abstract

We review the relation between the ratio of hadronic and electronic Z widths, R = Γ(Z → qq)/Γ(Z → e+e-) and the strong coupling constant at the Z mass, αs. The theoretical uncertainty of αs derived from R is estimated to be Δαs = ±0.002 (electroweak) ± 0.002 (QCD)-0.003+0.004 (mtop, mHiggs). © 1994.