Determination of the e(+)e(-)->gamma gamma(gamma) cross-section at centre-of-mass energies ranging from 189 GeV to 202 GeV

Determination of the e(+)e(-)->gamma gamma(gamma) cross-section at centre-of-mass energies ranging from 189 GeV to 202 GeV

A test of the QED process e+e- → γγ(γ) is reported. The data analysed were collected with the DELPHI detector in 1998 and 1999 at the highest energies achieved at LEP, reaching 202 GeV in the centre-of-mass. The total integrated luminosity amounts to 375.7 pb-1. The differential and total cross-sect...

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Bibliographic Details
Main Authors: Abreu, P, Adam, W, Adye, T, Adzic, P, Albrecht, Z, Alderweireld, T, Alekseev, G, Alemany, R, Allmendinger, T, Allport, P, Almehed, S, Amaldi, U, Amapane, N, Amato, S, Anassontzis, E, Andersson, P, Andreazza, A, Andringa, S, Antilogus, P, Apel, W, Arnoud, Y, Asman, B, Augustin, J, Augustinus, A, Baillon, P
Format: Journal article
Language:English
Published: 2000
Description
Summary:A test of the QED process e+e- → γγ(γ) is reported. The data analysed were collected with the DELPHI detector in 1998 and 1999 at the highest energies achieved at LEP, reaching 202 GeV in the centre-of-mass. The total integrated luminosity amounts to 375.7 pb-1. The differential and total cross-sections for the process e+e- → γγ were measured, and found to be in agreement with the QED prediction. 95% confidence level (C.L.) lower limits on the QED cut-off parameters of Λ+ > 330 GeV and λ- > 320 GeV were derived. A 95% C.L. lower bound on the mass of an excited electron of 311 GeV/c2 (for λγ = 1) was obtained, s-channel virtual graviton exchange was searched for, resulting in 95% C.L. lower limits on the string mass scale, M(S): M(S) > 713 GeV/c2 (λ = 1) and M(S) > 691 GeV/c2 (γ = -1). (C) 2000 Published by Elsevier Science B.V.

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