Measurement of the W-Pair Production Cross Section and W-Decay Branching Fractions in e+e- Interactions at sqrt{s}=189GeV

TL;DR

This paper reports measurements of W-pair production cross section and W decay branching fractions at 189 GeV using LEP data, confirming Standard Model predictions with high precision.

Contribution

First precise measurement of W-pair production cross section and W decay branching fractions at 189 GeV at LEP, aligning with Standard Model expectations.

Findings

W-pair production cross section measured as 16.24 pb

W hadronic branching fraction determined as 68.20%

Results agree with Standard Model predictions

Abstract

The data collected by the L3 experiment at LEP at a centre-of-mass energy of 188.6 GeV are used to measure the W-pair production cross section and the W-boson decay branching fractions. These data correspond to an integrated luminosity of 176.8pb^-1. The total cross section for W-pair production, combining all final states, is measured to be sigma_WW = 16.24 +/- 0.37(stat.) +/- 0.22(syst.) pb. Including our data collected at lower centre-of-mass energies, the hadronic branching fraction of the W-boson is determined to be B(W ->qq) = [68.20 +/- 0.68 (stat.) +/- 0.33 (syst.) ] %. The results agree with the Standard Model predictions.