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Measurement of the W+W−γ cross-section and first direct limits on anomalous electroweak quartic gauge couplings

Research output: Contribution to Journal/MagazineJournal articlepeer-review

  • G Abbiendi
  • K Ackerstaff
  • P F Akesson
  • G Alexander
  • J Allison
  • K J Anderson
  • S Arcelli
  • S Asai
  • S F Ashby
  • D Axen
  • G Azuelos
  • I Bailey
  • A H Ball
  • E Barberio
  • R J Barlow
  • J R Batley
  • S Baumann
  • T Behnke
  • K W Bell
  • G Bella
  • A Bellerive
  • S Bentvelsen
  • S Bethke
  • S Betts
  • O Biebel
  • A Biguzzi
  • I J Bloodworth
  • P Bock
  • J Bohme
  • O Boeriu
  • D Bonacorsi
  • M Boutemeur
  • S Braibant
  • P Bright-Thomas
  • L Brigliadori
  • R M Brown
  • H J Burckhart
  • P Capiluppi
  • R K Carnegie
  • A A Carter
  • J R Carter
  • C Y Chang
  • D G Charlton
  • D Chrisman
  • C Ciocca
  • P E L Clarke
  • E Clay
  • I Cohen
  • J E Conboy
  • V Kartvelishvili
  • OPAL Collaboration
<mark>Journal publication date</mark>30/12/1999
<mark>Journal</mark>Physics Letters B
Issue number2-3
Number of pages15
Pages (from-to)293-307
Publication StatusPublished
<mark>Original language</mark>English


A study of W+W- events accompanied by hard photon radiation produced in e(+)e(-) collisions at LEP is presented. Events consistent with two on-shell W-bosons and an isolated photon are selected from 183 pb(-1) of data recorded at root s = 189 GeV. From these data, 17 W+W- gamma candidates are selected with photon energy greater than 10 GeV, consistent with the Standard Model expectation. These events are used to measure the e(+)e(-) --> W+W- gamma cross-section within a set of geometric and kinematic cuts, <(sigma)over cap>(WW gamma) = 136 +/- 37 +/- 8 fb, where the first error is statistical and the second systematic. The photon energy spectrum is used to set the first direct, albeit weak, limits on possible anomalous contributions to the W+W- gamma gamma and W+W- gamma Z(0) vertices:

0.070GeV(-2) < a(0)/Lambda(2) < 0.070 GeV-2,

0.13GeV(-2) < a(c)/Lambda(2) < 0.19 GeV-2,

0.61GeV(-2) < a(n)/Lambda(2) < 0.57 GeV-2,

where Lambda represents the energy scale for new physics. (C) 1999 Published by Elsevier Science B.V. All rights reserved.