Measurement of the e+ e- ---> gamma gamma (gamma) cross-section at LEP energies
(1994) Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics — Vol. 327, n° 3-4, p. 386-396 (1994)
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- et. al.
- Abstract
- The total and the differential cross sections for the reaction e+e− → γγ(γ) have been measured with the DELPHI detector at LEP using an integrated luminosity of 36.9 pb−1. The results agree with the QED predictions and consequently there is no evidence for non-standard channels with the same experimental signature. The lower limits obtained on the QED cutoff parameters are Λ+ > 143 GeV and Λ− > 120 GeV, and the lower bound on the mass of an excited electron with an effective coupling constant λγ = 1 is 132 GeV/c2. Upper limits on the branching ratios for the decays Z0 → γγ, Z0 → π0γ, Z0 → ηγ and Z0 → γγγ have been determined to be 5.5 × 10−5, 5.5 × 10−5, 8.0 × 10−5, and 1.7 × 10−5 respectively. All the limits are at the 95% confidence level.
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Abreu, P., Adam, W., Adye, T., Agasi, E., Ajinenko, I., Cortina Gil, E., DELPHI Collaboration, & et al. (1994). Measurement of the e+ e- ---> gamma gamma (gamma) cross-section at LEP energies. Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics, 327(3-4), 386-396. https://doi.org/10.1016/0370-2693(94)90745-5 (Original work published 1994)