Abstract
Cross-sections and angular distributions for the production of events with single and multiple photons are measured from data recorded with the OPAL detector at the recently upgraded LEP collider. The measured cross-sections are generally consistent with Standard Model expectations for the e+e- → vv̄γ(γ) and e+e- → γγ(γ) processes. Six events with an acoplanar photon pair and large missing mass are found. The observed number of events is larger than expected from e+e- → vv̄γγ; however, the missing mass distribution is compatible with the Z0 resonance. Deviations from QED are constrained by the data on e+e- → γγ(γ). Lower limits are set at 95% confidence level on the QED cut-off parameters Λ+ and Λ- of 152 GeV and 142 GeV, respectively, and also on the mass of an excited electron of 147 GeV.
Original language | English |
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Pages (from-to) | 222-234 |
Number of pages | 13 |
Journal | Physics Letters B |
Volume | 377 |
Issue number | 1-3 |
DOIs | |
State | Published - Jun 6 1996 |
Externally published | Yes |
Funding
Forschung und Technologie, Germany, National Research Council of Canada, Hungarian Foundation for Scientific Research,O TKA T-01 6660, and OTKA F-015089. We particularly wish to thank the SL Division for the excellent start-up and performance of the LEP acceleratori n the data taking run at centre-of-mass energies of 130-140 GeV and for their continuing close cooperation with our experimental group. In addition to the support staff at our own institutions we are pleasedt o acknowledget he Departmento f Energy, USA, National Science Foundation, USA, Particle Physics and Astronomy Research Council. UK Natural Sciences and Engineering Research Council, Canada, Israel Ministry of Science, Israel Science Foundation, administeredb y the Israel Academy of Science and Humanities, Minerva Gesellschaft, Japanese Ministry of Education, Science and Culture (the Monbusho) and a grant under the Monbusho International Science ResearchP rogram. German Israeli Bi-national Science Foundation (GIF), Direction des Sciences de la Matike du Commissariat a 1’Energie Atomique, France, Bundesministerium fur Bildung, Wissenschaft,
Funders | Funder number |
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Hungarian Foundation for Scientific Research | OTKA F-015089, O TKA T-01 6660 |
Israel Ministry of Science, Israel Science Foundation | |
Minerva Gesellschaft | |
Monbusho International Science ResearchP rogram | |
Natural Sciences and Engineering Research Council of Canada | |
National Research Council Canada | |
Ministry of Education, Culture, Sports, Science and Technology | |
Israel Academy of Sciences and Humanities |