The process e+e- → γγ(γ) is studied using data recorded with the OPAL detector at LEP. The data sample corresponds to a total integrated luminosity of 56.2 pb-1 taken at a centre-of-mass energy of 183 GeV. The measured cross-section agrees well with the expectation from QED. A fit to the angular distribution is used to obtain improved limits at 95% CL on the QED cut-off parameters: Λ+> 233 GeV and Λ_> 265 GeV as well as a mass limit for an excited electron, Me* > 227 GeV assuming equal e * eγ and eeγ couplings. No evidence for resonance production is found in the invariant mass spectrum of photon pairs. Limits are obtained for the cross-section times branching ratio for a resonance decaying into two photons.
|Number of pages||12|
|Journal||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|State||Published - 22 Oct 1998|
ASJC Scopus subject areas
- Nuclear and High Energy Physics