\(\mathrm{W^+W^-}\) production and triple gauge boson couplings at LEP energies up to 183 GeV

  • The OPAL Collaboration
  • G. Abbiendi et al.
Experimental physics


A study of W-pair production in \({\rm e^+e^-}\) annihilations at LEP is presented, based on \(877\,{\rm W^+W^-}\) candidates corresponding to an integrated luminosity of 57 pb\(^{-1}\) at \(\sqrt s=183\) GeV. Assuming that the angular distributions of the W-pair production and decay, as well as their branching fractions, are described by the Standard Model, the W-pair production cross-section is measured to be \(15.43\pm 0.61 ({\rm stat.}) \pm 0.26 ({\rm syst.})\) pb. Assuming lepton universality and combining with our results from lower centre-of-mass energies, the W branching fraction to hadrons is determined to be \(67.9 \pm 1.2 ({\rm stat.})\pm 0.5 ({\rm syst.})\)%. The number of W-pair candidates and the angular distributions for each final state (\({\rm q \bar q} \bar \ell \nu_\ell\), \({\rm q \bar q q \bar q}, \bar \ell \nu_\ell \ell^\prime \bar \nu_{\ell^\prime })\) are used to determine the triple gauge boson couplings. After combining these values with our results from lower centre-of-mass energies we obtain \(\Delta \kappa_\gamma = 0.11^{+0.52}_{-0.37}\), \(\Delta g^{\rm z}_1 = 0.01^{+ 0.13}_{-0.12}\) and \(\lambda = -0.10^{+0.13}_{-0.12}\), where the errors include both statistical and systematic uncertainties and each coupling is determined by setting the other two couplings to the Standard Model value. The fraction of W bosons produced with a longitudinal polarisation is measured to be \(0.242 \pm 0.091({\rm stat.}) \pm 0.023 ({\rm syst.})\). All these measurements are consistent with the Standard Model expectations.


Angular Distribution Gauge Boson Systematic Uncertainty Model Expectation Longitudinal Polarisation 
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Copyright information

© Springer-Verlag Berlin Heidelberg 1999

Authors and Affiliations

  • The OPAL Collaboration
  • G. Abbiendi et al.
    • 1
  1. 1. Dipartimento di Fisica dell' Università di Bologna and INFN, I-40126 Bologna, Italy IT

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