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  • Tests of QED at LEP energie...
    Alviggi, M.G.; An, Q.; Arefiev, A.; Baschirotto, A.; Basile, M.; Battiston, R.; Berdugo, J.; Betev, B.L.; Biland, A.; Bourquin, M.; Branson, J.G.; Buytenhuijs, A.; Capell, M.; Carlino, G.; Casaus, J.; Cerrada, M.; Chamizo, M.; Chen, C.; Chen, G.; Chen, M.; Chien, C.Y.; Cindolo, F.; Colino, N.; Cui, X.T.; Cui, X.Y.; Degré, A.; Dénes, E.; Dionisi, C.; Engler, A.; Eppling, F.J.; Fabre, M.; Favara, A.; Felcini, M.; Ferguson, T.; Field, J.H.; Forconi, G.; Gougas, A.; He, J.T.; Innocente, V.; Kasser, A.; Kim, J.K.; Kinnison, W.W.; Kirsch, S.; Klimentov, A.; Kramer, T.; Kuijten, H.; Lapoint, C.; Leggett, C.; Leonardi, E.; Lin, W.T.; Lindemann, B.; Lohmann, W.; Lu, Y.S.; Lübelsmeyer, K.; Luci, C.; Malinin, A.; Mele, S.; Meschini, M.; Mihul, A.; Monaco, V.; Paoletti, S.; Pascale, G.; Pinto, J.C.; Pistolesi, E.; Read, K.; Reucroft, S.; Rosier-Lees, S.; Rosselet, Ph; van Rossum, W.; Roth, S.; Salicio, J.; Schmitz, P.; Schneegans, M.; Schoeneich, B.; Seiler, P.G.; Shevchenko, S.; Spickermann, T.; Stickland, D.P.; Stoyanov, B.; Sudhakar, K.; Susinno, G.F.; Syed, A.A.; Ting, Samuel C.C.; Valente, E.; Vikas, P.; Vorobyov, An.A.; Wallraff, W.; Wang, J.C.; Weber, A.; Wittgenstein, F.; Yao, X.Y.; Ye, C.H.; Yunus, N.; Zaccardelli, C.; Zalite, An; Zemp, P.; Zeng, M.; Zhu, G.Y.; Zhu, R.Y.; Zichichi, A.

    Physics letters. B, 06/1995, Letnik: 353, Številka: 1
    Journal Article

    Total and differential cross sections for the process e +e − → γγ( γ), and the total cross section for the process e +e − → γγγ, are measured at energies around 91 GeV using the data collected with the L3 detector from 1991 to 1993. We set lower limits, at 95% CL, on a contact interaction energy scale parameter Λ > 602 GeV, on the mass of an excited electron m e ∗ >146 GeV and on the QED cut-off parameters Λ + > 149 GeV and Λ_ > 143 GeV. Upper limits are also set o branching fractions of Z decaying into γγ, π° and ηγ of 5.2 × 10 −5, 5.2 × 10 −5 and 7.6 × 10 −5 respectively. The reactions e +e − → ℓ +ℓ − nγ (ℓ = e, μ, τ) are studied using the data collected from 1990 to 1994. The data are consistent with the QED expectations.