Measurement of the polar-angle distribution of leptons from W boson decay as a function of the W transverse momentum in pp[over ¯] collisions at sqrt[s]=1.8 TeV

We present a measurement of the polar-angle distribution of leptons from W boson decay, as a function of the W transverse momentum. The measurement uses an 80±4 pb-1 sample of pp̅ collisions at sqrt[s]=1.8 TeV collected by the CDF detector and includes data from both the W→e+ν and W→μ+ν decay channels. We fit the W boson transverse mass distribution to a set of templates from a Monte Carlo event generator and detector simulation in several ranges of the W transverse momentum. The measurement agrees with the standard model expectation, whereby the ratio of longitudinally to transversely polarized W bosons, in the Collins-Soper W rest frame, increases with the W transverse momentum at a rate of approximately 15% per 10 GeV/c

Combination of CDF and D0 results on the W boson mass and width

The results based on 1992–95 data (Run 1) from the CDF and D0 experiments on the measurements of the W boson mass and width are presented, along with the combined results. We report a Tevatron collider average MW=80.456±0.059  GeV. We also report the Tevatron collider average of the directly measured W boson width ΓW=2.115±0.105  GeV. We describe a new joint analysis of the direct W mass and width measurements. Assuming the validity of the standard model, we combine the directly measured W boson width with the width extracted from the ratio of W and Z boson leptonic partial cross sections. This combined result for the Tevatron is ΓW=2.135±0.050  GeV. Finally, we use the measurements of the direct total W width and the leptonic branching ratio to extract the leptonic partial width Γ(W→eν)=224±13  MeV

Measurement of the W boson mass with the collider detector at Fermilab

We present a measurement of the W boson mass using data collected with the CDF detector during the 1994–1995 collider run at the Fermilab Tevatron. A fit to the transverse mass spectrum of a sample of 30115 W→eν events recorded in an integrated luminosity of 84 pb-1 gives mass MW=80.473±0.065(stat)±0.092(syst) GeV/c2. A fit to the transverse mass spectrum of a sample of 14740 W→μν events from 80 pb-1 gives a mass MW=80.465±0.100(stat)±0.103(syst) GeV/c2. The dominant contributions to the sys- tematic uncertainties are the uncertainties in the electron energy scale and the muon momentum scale, 0.075 GeV/c2 and 0.085 GeV/c2, respectively. The combined value for the electron and muon channel is MW=80.470±0.089 GeV/c2. When combined with previously published CDF measurements, we obtain MW=80.433±0.079 GeV/c2