Multiphoton final states in e+ e- collisions at s**(1/2) = 130-GeV - 172-GeV
Collaboration
25 pages
Published in:
- Eur.Phys.J.C 1 (1998) 21-30
e-Print:
- hep-ex/9709002 [hep-ex]
Report number:
- CERN-PPE-97-109
Experiments:
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Abstract:
The process e^+e^- -> gamma gamma (gamma) 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: Lambda_+ > 195 GeV and Lambda_- > 210 GeV (95% CL). In addition, limits on non-standard e^+e^-gamma couplings and contact interactions, as well as a 95% CL mass limit for an excited electron, M_{e^*} > 194 GeV for an e^+e^-gamma coupling kappa = 1, are determined.- electron positron: colliding beams
- electron positron: annihilation
- photon: multiple production
- photon: multiplicity
- quantum electrodynamics: Lambda parameter
- angular distribution
- coupling: (positron electron photon)
- search for: new interaction
- resonance: search for
- channel cross section
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