Measurement of the e(+)e(-)->gamma gamma(gamma) cross section at the LEP energies

The total and the differential cross-sections for the reaction e(+)e(-) --> gamma gamma(gamma) have been measured with the DELPHI detector at LEP at centre-of-mass energies from 130 to 183 GeV for an integrated luminosity of 78.19 pb(-1). The results agree with the QED predictions. The lower limits (obtained including previously published results at the Z(0) energies) on the QED cutoff parameters are Lambda(+) > 253 GeV and Lambda(-) > 225 GeV and the lower bound on the mass of an excited electron with an effective coupling constant lambda(gamma) = 1 is 231 GeV/c(2). All the Limits are at the 95% confidence level. (C) 1998 Published by Elsevier Science B.V. All rights reserved.