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Multi-photon final states in e+e− collisions at ∝s =130-172 GeV

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<mark>Journal publication date</mark>03/1998
<mark>Journal</mark>European Physical Journal C: Particles and Fields
Issue number1
Number of pages10
Pages (from-to)21-30
Publication StatusPublished
<mark>Original language</mark>English


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 25.38 pb−1 taken at centre-of-mass energies of 130–172 GeV. The measured cross-sections agree well with the expectation from QED. In a combined fit using data from all centre-of-mass energies, the angular distribution is used to obtain improved limits on the cut-off parameters: Λ+ > 195 GeV and Λ− > 210 GeV (95% CL). In addition, limits on nonstandard e+e−γ couplings and contact interactions, as well as a 95% CL mass limit for an excited electron,Me*= > 194 GeV for an e+e−γ coupling κ = 1, are determined.