A first measurement of the cross section of the process e(+)e(-) --> Z gamma gamma is reported using a total integrated luminosity of 231 pb(-1) collected with the L3 detector at centre-of-mass energies of 182.7 GeV and 188.7 GeV. By selecting hadronic events with two isolated photons the e(+)e(-) --> Z gamma gamma cross section is measured to be 0.49(-0.17)(+0.20) +/- 0.04 pb at 182.7 GeV and 0.47 +/- 0.10 +/- 0.04 pb at 188.7 GeV. The measurements are consistent with Standard Model expectations. Limits on Quartic Gauge Boson Couplings a(0)/Lambda(2) and a(c)/Lambda(2) of -0.009 GeV-2 < a(0)/Lambda(2) < 0.008 GeV-2 and -0.007 GeV-2 < a(c)/Lambda(2) < 0.013 GeV-2 are derived at 95% confidence level.
Measurement of the e+ e- ---> Z gamma gamma cross-section and determination of quartic gauge boson couplings at LEP
BATTISTON, Roberto;BERTUCCI, Bruna;AMBROSI, Giovanni;BURGER, WILLIAM J.;FIANDRINI, Emanuele;M. Pauluzzi
2000
Abstract
A first measurement of the cross section of the process e(+)e(-) --> Z gamma gamma is reported using a total integrated luminosity of 231 pb(-1) collected with the L3 detector at centre-of-mass energies of 182.7 GeV and 188.7 GeV. By selecting hadronic events with two isolated photons the e(+)e(-) --> Z gamma gamma cross section is measured to be 0.49(-0.17)(+0.20) +/- 0.04 pb at 182.7 GeV and 0.47 +/- 0.10 +/- 0.04 pb at 188.7 GeV. The measurements are consistent with Standard Model expectations. Limits on Quartic Gauge Boson Couplings a(0)/Lambda(2) and a(c)/Lambda(2) of -0.009 GeV-2 < a(0)/Lambda(2) < 0.008 GeV-2 and -0.007 GeV-2 < a(c)/Lambda(2) < 0.013 GeV-2 are derived at 95% confidence level.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
