Research output: Contribution to journal › Journal article
|Journal publication date||08/2004|
|Journal||Physical Review D|
|Number of pages||11|
Anomalous quartic couplings between the electroweak gauge bosons may contribute to the nu(nu) over bar gammagamma and q (q) over bar gammagamma 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 nu(nu) over bar gammagamma and q (q) over bar gammagamma events in which the two photons are reconstructed within the detector acceptance. The cross section for the process e(+)e(-)-->q (q) over bar gammagamma is measured. Averaging over all energies, the ratio of the observed e(+)e(-)-->q (q) over bar gammagamma 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 nu(nu) over bar gammagamma and q (q) over bar gammagamma data are used to constrain possible anomalous W(+)W(-)gammagamma and ZZgammagamma couplings. Combining with previous OPAL results from the W(+)W(-)gamma final state, the 95% confidence level limits on the anomalous coupling parameters a(0)(Z), a(c)(Z), a(0)(W) and a(c)(W) are found to be -0.007 GeV-2<a(0)(Z)/Lambda(2)<0.023 GeV-2, -0.029 GeV-2<a(c)(Z)/Lambda(2)<0.029 GeV-2, -0.020 GeV-2<a(0)(W)/Lambda(2)<0.020 GeV-2, -0.052 GeV-2<a(c)(W)/Lambda(2)<0.037 GeV-2, where Lambda is the energy scale of the new physics. Limits found when allowing two or more parameters to vary are also presented.