par Abreu, Pedro;Bertrand, Daniel 
;Bricman, Claude ;Chorowicz, Ingrid ;Grard, Fernand ;Herquet, Philippe ;Lemonne, Jacques ; [et al.]
Référence Physics letters. Section B, 268, 2, page (296-304)
Publication Publié, 1991
;Bricman, Claude ;Chorowicz, Ingrid ;Grard, Fernand ;Herquet, Philippe ;Lemonne, Jacques ; [et al.]Référence Physics letters. Section B, 268, 2, page (296-304)
Publication Publié, 1991
Article révisé par les pairs
| Résumé : | The total and differential cross-sections for the reaction e+e- → γγ(γ) are measured at centre of mass energies around 91 GeV using an integrated luminosity of 4.7 pb-1. The aggreement with QED prediction is good. Consequently there is no evidence for non-standard channels which would have the same experimental signature. The lower limits on the QED cuttoff parameters are Λ+ > 113 GeV and Λ- > 95 GeV. An upper limit on the effective coupling between a possible excited electron and the gamma is derived. At 95% confidence level the branching ratios for Z0 decay into π0γ, ηψ and γγγ are below 1.5 × 10-4, 2.8 × 10-4 and 1.4 × 10-4 respectively. |
