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 √S = 189 GeV. From these data, 17 W+W- γ 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-γ cross-section within a set of geometric and kinematic cuts, σwwγ = 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- γ and W+W- γZ(o) vertices: -0.070GeV-2 < a(o)/Λ2 < 0.070 GeV-2, -0.13GeV-2 < a(c)/Λ2 < 0.19GeV-2, -0.61GeV-2 < a(n)/Λ2 < 0.57 GeV-2, where A represents the energy scale for new physics. (C) 1999 Published by Elsevier Science B.V.
|Number of pages||15|
|Journal||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|State||Published - 30 Dec 1999|