We have studied the process e(+)e(-)-->n gamma (n greater than or equal to 2) at an average center-of-mass energy of 133 GeV using the L3 detector at LEP. For an integrated luminosity of 4.95 pb(-1) we find one gamma gamma gamma gamma(gamma) final state with only hard photons. The rates of both gamma gamma gamma and gamma gamma events are consistent with QED expectations. The cross section of the reaction e(+)e(-) -->gamma gamma(gamma) in the polar range 16 degrees<164 degrees is measured to be 22.6+/-2.2 ph. Decays into photons of narrow scalar resonances with masses between 90 and 130 GeV are not observed. The observation of the event with four energetic photons is consistent with QED although the kinematic configuration of the photons is atypical.

Observation of multiple hard photon final states at root s=130-140 GeV at LEP

FERRONI, Fernando
1996

Abstract

We have studied the process e(+)e(-)-->n gamma (n greater than or equal to 2) at an average center-of-mass energy of 133 GeV using the L3 detector at LEP. For an integrated luminosity of 4.95 pb(-1) we find one gamma gamma gamma gamma(gamma) final state with only hard photons. The rates of both gamma gamma gamma and gamma gamma events are consistent with QED expectations. The cross section of the reaction e(+)e(-) -->gamma gamma(gamma) in the polar range 16 degrees<164 degrees is measured to be 22.6+/-2.2 ph. Decays into photons of narrow scalar resonances with masses between 90 and 130 GeV are not observed. The observation of the event with four energetic photons is consistent with QED although the kinematic configuration of the photons is atypical.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/20.500.12571/2952
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