Measurement of the ratio R≡σ W Br(W→μν)/σ z Br (Z→μμ) and Γ W tot at the CERN proton-antiproton collider

An analysis of W and Z boson production at UA1, using 4.66 pb -1 of data from the 1988 and 1989 CERN pp Collider runs at s=0.63 TeV, yields R≡σ W Br(W→μv)/σ z Br (Z→μμ)=10.4 -1.5 +1.8 stat.± 0.8(syst.) We find R=9.5 -1.0 +1.1 (stat.+syst.) when combining all available UA1 data, in both the electron and muon channel, taken in the period 1983-1989. In the framework of the standard model, the value of R is used to infer the total width of the W boson, Γ W tot =2.18 -0.24 +0.26 (exp.)±0.04(theory) GeV/c 2 . © 1991.