We have searched for anomalous Z --> gamma gamma gamma events with the L3 detector at LEP. No significant deviations from the expected QED e(+)e(-)-->gamma gamma gamma events are observed. The branching ratio upper limit for a composite Z decaying directly into three photons is found to be 1.0 x 10(-1) at 95% C.L. The branching ratio upper limits for the process Z-->gamma X,X-->gamma gamma are in the range of 0.4 to 1.3 x 10(-5), depending on the mass and width of the scalar particle X. In the context of a model with magnetic monopoles coupling to the Z, we find BR(Z-->gamma gamma gamma) < 0.8 x 10(-5) at 95% C.L; this results in a lower mass limit of 510 GeV for a magnetic monopole.
Search for anomalous Z → γγγ events at LEP
MONACO, Vincenzo;
1995-01-01
Abstract
We have searched for anomalous Z --> gamma gamma gamma events with the L3 detector at LEP. No significant deviations from the expected QED e(+)e(-)-->gamma gamma gamma events are observed. The branching ratio upper limit for a composite Z decaying directly into three photons is found to be 1.0 x 10(-1) at 95% C.L. The branching ratio upper limits for the process Z-->gamma X,X-->gamma gamma are in the range of 0.4 to 1.3 x 10(-5), depending on the mass and width of the scalar particle X. In the context of a model with magnetic monopoles coupling to the Z, we find BR(Z-->gamma gamma gamma) < 0.8 x 10(-5) at 95% C.L; this results in a lower mass limit of 510 GeV for a magnetic monopole.File | Dimensione | Formato | |
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