Multi-photon production in e+e− collisions at √s = 189 GeV

Kartvelishvili, Vakhtang (1999) Multi-photon production in e+e− collisions at √s = 189 GeV. Physics Letters B, 465 (1-4). pp. 303-314. ISSN 0370-2693

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Abstract

The process e+e−→γγ(γ) is studied using data recorded with the OPAL detector at LEP. The data sample taken at a centre-of-mass energy of 189 GeV corresponds to a total integrated luminosity of 178 pb−1. 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+> 304 GeV and Λ−> 295 GeV as well as a mass limit for an excited electron, Me* > 306 GeV assuming equal e*ey and eeγ couplings. Graviton exchange in the context of theories with higher dimensions is excluded for scales G+< 660 GeV and G−< 634 GeV. 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 and produced in association with another photon.

Item Type: Journal Article
Journal or Publication Title: Physics Letters B
Uncontrolled Keywords: /dk/atira/pure/subjectarea/asjc/3100/3106
Subjects:
Departments: Faculty of Science and Technology > Physics
ID Code: 82825
Deposited By: ep_importer_pure
Deposited On: 14 Nov 2016 10:36
Refereed?: Yes
Published?: Published
Last Modified: 29 Jan 2020 03:34
URI: https://eprints.lancs.ac.uk/id/eprint/82825

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