M. Acciarri et al., Measurement of the W+W-gamma cross section and direct limits on anomalous quartic gauge boson couplings at LEP, PHYS LETT B, 490(3-4), 2000, pp. 187-195
The process e(+)e(-)-->W(+)W(-)gamma is analysed using the data collected w
ith the L3 detector at LEP at a centre-of-mass energy of 188.6 GeV, corresp
onding to an integrated luminosity of 176.8 pb(-1). Based on a sample of 42
selected W+W- candidates containing an isolated hard photon, the W(+)W(-)g
amma cross section, defined within phase-space cuts, is measured to be: sig
ma(WW gamma) = 290 +/- 80 +/- 16 fb, consistent with the Standard Model exp
ectation. Including the process e(+)c(-)-->upsilon<(upsilon)over bar>gamma
gamma, limits are derived on anomalous contributions to the Standard Model
quartic vertices W(+)W(-)gamma gamma and W(+)W(-)Z gamma at 95% CL: -0.043
GeV-2 < a(0)/Lambda(2) < 0.043 GeV-2, -0.08 GeV-2 < a(c)/Lambda(2) < 0.13 G
eV-2, -0.41 GeV-2 < a(n)/Lambda(2) < 0.37 GeV-2. (C) 2000 Elsevier Science
B.V. All rights reserved.