The reaction e+e- → γγ(γ) at Z0 energies

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...

詳細記述

書誌詳細
主要な著者: Abreu, P, Adam, W, Adami, F, Adye, T, Akesson, T, Alekseev, G, Allen, P, Almehed, S, Alted, F, Alvsvaag, S, Amaldi, U, Anassontzis, E, Antilogus, P, Apel, W, Apsimon, R, Åsman, B, Astier, P, Augustin, J, Augustinus, A, Baillon, P, Bambade, P, Barao, F, Barbiellini, G, Bardin, D, Baroncelli, A
フォーマット: Journal article
言語:English
出版事項: 1991
その他の書誌記述
要約: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. © 1991.