Extraction of the Width of the W Boson from Measurements of sigma(ppbar->W+X)B(W->e nu) and sigma(ppbar->Z+X)B(Z->e e) and their Ratio

TL;DR

This paper measures the production cross sections and decay properties of W and Z bosons in proton-antiproton collisions at 1.8 TeV, deriving the W boson width and setting limits on non-standard decay modes.

Contribution

It provides new precise measurements of W and Z boson production rates and decay widths, including the W width and limits on invisible decay channels, using data from the Fermilab Tevatron.

Findings

Measured sigma(ppbar->W+X)B(W->e nu) = 2310 pb

Derived W boson width Gamma_W = 2.130 GeV

Set upper limit on invisible decay width Gamma_W^{inv} = 0.168 GeV

Abstract

We report on measurements of inclusive cross sections times branching fractions into electrons for W and Z bosons produced in ppbar collisions at sqrts=1.8 TeV.From an integrated luminosity of 84.5 inverse pb recorded in 1994--1995 using the D0 detector at the Fermilab Tevatron, we determine sigma(ppbar->W+X)B(W->e nu) = 2310 +- 10(stat) +- 50(syst) +- 100(lum) pb and sigma(ppbar->Z+X)B(Z->e e) = 221 +- 3(stat) +- 4(syst) +- 10(lum) pb. From these, we derive their Ratio R = 10.43 +- 0.15(stat) +- 0.20(syst) +- 0.10(NLO), B(W->e nu) = 0.1066 +- 0.0015(stat) +- 0.0021(syst) +- 0.0011(theory)+- 0.0011(NLO), and Gamma_W = 2.130 +- 0.030(stat) +- 0.041(syst) +- 0.022(theory) +- 0.021(NLO) GeV. We use the latter to set a 95% confidence level upper limit on the partial decay width of the W boson into non-standard model final states, Gamma_W^{inv}, of 0.168 GeV. Combining these results with those from the 1992--1993 data gives R = 10.54 +- 0.24, Gamma_W = 2.107 +- 0.054 GeV, and a 95% C.L. upper limit on Gamma_W^{inv} of 0.132 GeV. Using a sample with a luminosity of 505 inverse nb taken at sqrts=630 GeV, we measure sigma(ppbar->W+X)B(W->e nu) = 658 +- 67 pb.