Determination of the e+ e- --> gamma gamma (gamma) cross-section at centre-of-mass energies ranging from 189-GeV to 202-GeV
Collaboration
18 pages
Published in:
- Phys.Lett.B 491 (2000) 67-80
e-Print:
- hep-ex/0103005 [hep-ex]
PDG: Mass Limits on
Report number:
- CERN-EP-2000-094
Experiments:
View in:
Citations per year
Abstract: (Elsevier)
A test of the QED process e + e − → γγ ( γ ) is reported. The data analysed were collected with the DELPHI detector in 1998 and 1999 at the highest energies achieved at LEP, reaching 202 GeV in the centre-of-mass. The total integrated luminosity amounts to 375.7 pb −1 . The differential and total cross-sections for the process e + e − → γγ were measured, and found to be in agreement with the QED prediction. 95% confidence level (C.L.) lower limits on the QED cut-off parameters of Λ + >330 GeV and Λ − >320 GeV were derived. A 95% C.L. lower bound on the mass of an excited electron of 311 GeV/ c 2 (for λ γ =1) was obtained. s-channel virtual graviton exchange was searched for, resulting in 95% C.L. lower limits on the string mass scale, M S : M S >713 GeV/ c 2 ( λ =1) and M S >691 GeV/ c 2 ( λ =−1).Note:
- 18 pages, 4 figures Report-no: CERN-EP/2000-094 Journal-ref: Phys. Lett. B 491 (2000) 67-80
- electron positron: colliding beams
- electron positron: annihilation
- photon: multiple production
- quantum electrodynamics: validity test
- quantum electrodynamics: Lambda parameter
- e*
- mass: lower limit
- exchange: graviton
- cross section: energy dependence
- angular distribution
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