Abstract
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.
Original language | English |
---|---|
Pages (from-to) | 379-390 |
Number of pages | 12 |
Journal | Physics Letters B |
Volume | 438 |
Issue number | 3-4 |
DOIs | |
State | Published - Oct 22 1998 |
Externally published | Yes |
Funding
We particularly wish to thank the SL Division for the efficient operation of the LEP accelerator at all energies and for their continuing close cooperation with our experimental group. We thank our colleagues from CEA, DAPNIA/SPP, CE-Saclay for their efforts over the years on the time-of-flight and trigger systems which we continue to use. In addition to the support staff at our own institutions we are pleased to acknowledge the Department of Energy, USA; National Science Foundation, USA; Particle Physics and Astronomy Research Council, UK; Natural Sciences and Engineering Research Council, Canada; Israel Science Foundation, administered by the Israel Academy of Science and Humanities; Minerva Gesellschaft; Benoziyo Center for High Energy Physics; Japanese Ministry of Education, Science and Culture (the Monbusho) and a grant under the Monbusho International Science Research Program; German Israeli Bi-national Science Foundation (GIF).
Funders | Funder number |
---|---|
German Israeli Bi-national Science Foundation | |
Minerva Gesellschaft | |
National Science Foundation | |
U.S. Department of Energy | |
Natural Sciences and Engineering Research Council of Canada | |
Ministry of Education, Culture, Sports, Science and Technology | |
Israel Academy of Sciences and Humanities | |
Israel Science Foundation |