Research output: Contribution to Journal/Magazine › Journal article › peer-review
| <mark>Journal publication date</mark> | 29/01/2004 |
|---|---|
| <mark>Journal</mark> | Physics Letters B |
| Issue number | 1-2 |
| Volume | 580 |
| Number of pages | 20 |
| Pages (from-to) | 17-36 |
| Publication Status | Published |
| <mark>Original language</mark> | English |
A study of W+W- events accompanied by hard photon radiation, Egamma > 2.5 GeV, produced in e(+)e(-) collisions at LEP is presented. Events consistent with being two on-shell W-bosons and an isolated photon are selected from 681 pb(-1) of data recorded at 180 GeV < roots < 209 GeV. From the sample of 187 selected W(+)W(-)gamma candidates with photon energies greater than 2.5 GeV, the W(+)W(-)gamma cross-section is determined at five values of roots. The results are consistent with the Standard Model expectation. Averaging over all energies, the ratio of the observed cross-section to the Standard Model expectation is
R(data/SM) = 0.99 +/- 0.09 +/- 0.04,
where the errors represent the statistical and systematic uncertainties respectively. These data provide constraints on the related O(alpha) systematic uncertainties on the measurement of the W-boson mass at LEP. Finally, the data are used to derive 95% confidence level upper limits on possible anomalous contributions to the W(+)W(-)gammagamma and W(+)W(-)Z(0)y vertices:
-0.020 GeV-2 < a(0)/Lambda(2) < 0.020 GeV-2,
-0.053 GeV-2 < a(c)/Lambda(2) < 0.037 GeV-2,
-0.16 GeV-2 < a(n)/Lambda(2) < 0.15 GeV-2,
where Lambda represents the energy scale for new physics and a(0), a(c) and a(n) are dimensionless coupling constants. (C) 2003 Elsevier B.V. All rights reserved.