Anomalous quartic couplings between the electroweak gauge bosons may contribute to the ννγγ and qq̄γγ final states produced in e+e- collisions. This analysis uses the LEP2 OPAL data sample at center-of-mass energies up to 209 GeV. Event selections identify ννγγ and qq̄γγ events in which the two photons are reconstructed within the detector acceptance. The cross section for the process e+e-→qq̄γγ is measured. Averaging over all energies, the ratio of the observed e +e-→qq̄γγ cross section to the standard model expectation is R(data/SM) = 0.92±0.07±0.04, where the errors represent the statistical and systematic uncertainties respectively. The ννγγ and qq̄γγ data are used to constrain possible anomalous W+W- γγ and ZZγγ couplings. Combining with previous OPAL results from the W + W- γ final state, the 95% confidence level limits on the anomalous coupling parameters a0Z, a cZ, a0W and ac W are found to be -0.007 GeV-2<a0 Z/Λ2 <0.023 GeV-2, -0.029 GeV -2<acZ/Λ2<0.029 GeV-2, -0.020 GeV-2<a0W/ Λ2<0.020 GeV-2, -0.052 GeV -2<acW/Λ2<0.037 GeV-2, where Λ is the energy scale of the new physics. Limits found when allowing two or more parameters to vary are also presented.
|Journal||Physical Review D - Particles, Fields, Gravitation and Cosmology|
|Publication status||Published - Aug 15 2004|
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)