DØ WZ Cross Section

DØ WZ Cross Section Subgroup

The measurement of the production cross sections times leptonic branching ratios for W and Z bosons can be used to test QCD predictions of W and Z production and to make a determination of the width of the W boson. Precise measurements of the total width of the W boson can, in principle, be used to constrain the Higgs boson mass and are also sensitive to non-standard-model decay modes of the W boson.

We have new results (Spring 99) on the W and Z cross sections times slectronic brancing fraction and on the W width (see plots below).

Our Run 1a results have been published, see
W and Z Boson Production in pbarp Collisions at sqrt s = 1.8 TeV
Phys. Rev. Letters {75} 1456 (1995), FERMILAB PUB-95/130-E

and

Measurement of W and Z boson production cross sections (Run Ia).
Submitted to Phys. Rev. D. {xx} pppp 1999 , FERMILAB PUB-99/015-E, hep-ex/9901040.

We also have results on the W -> tau nu decay channel.

DØ W -> e nu and Z -> ee Cross Section Results and Plots
(Click on the plot to get the postscript file)

Using Run 1b data corresponding to 84.5 pb^-1, we observe 67078 W -> e nu candidate events and 5397 Z -> ee candidate events. We determine the cross section times branching ratio for W and Z production to be

sigma(p pbar -> W + X) * B(W -> e nu) = 2310 +- 10(stat) +- 50(syst) +- 100 (lum) pb

sigma(p pbar -> Z + X) * B(Z -> ee) = 221 +- 3(stat) +- 4(syst) +- 10(lum) pb

The ratio R = sigmaW*B(W->e nu) / sigmaZ*B(Z->ee) is determined to be

R = 10.43 +- 0.15(stat) +- 0.20(syst) +- 0.10 (NLO)

In this ratio many of the systematic uncertainties cancel, including that in the integrated luminosity.

A preliminary combination with the CDF 1a+1b results gives:

DØ+CDF (1a+1b) preliminary W branching ratio to e nu: B(W -> e nu) = 0.1043 +- 0.0025

DØ+CDF (1a+1b) preliminary W inclusive width: Gamma(W) = 2.171 +- 0.052 GeV

p pbar -> W + X; W -> e nu and p pbar -> Z + X; Z -> ee cross section times branching fraction measurements from DØ and CDF. Note that DØ and CDF use different total ppbar cross sections to determine their luminosities. Consequently, there is a 6.2% offset in the normalizations, i.e. divide the CDF cross sections shown here by 1.062 to get the DØ normalization.

Summary of W branching ratio measurements.

Summary of W width measurements.

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This page maintained by John Ellison
Last modified: Fri Mar 10 14:37:13 CST 2000

	p pbar -> W + X; W -> e nu and p pbar -> Z + X; Z -> ee cross section times branching fraction measurements from DØ and CDF. Note that DØ and CDF use different total ppbar cross sections to determine their luminosities. Consequently, there is a 6.2% offset in the normalizations, i.e. divide the CDF cross sections shown here by 1.062 to get the DØ normalization.
	Summary of W branching ratio measurements.
	Summary of W width measurements.