First evidence of hard scattering processes in single tagged gamma gamma collisions

Abreu, P.;Adam, W.;Adye, T.;Agasi, E.;DELPHI Collaboration;et.al.
(1995) Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics — Vol. 342, n° 1–4, p. 402-416 (1995)

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Authors
  • Abreu, P.
    Author
  • Adam, W.
    Author
  • Adye, T.
    Author
  • Agasi, E.
    Author
  • Author
  • DELPHI Collaboration
    Author
  • et. al.
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Abstract
For the first time, multihadronic production from single tagged γγ collisions has been studied, where one of the scattered leptons was tagged at very low virtual photon absolute mass squared (〈Q2〉 = 0.06 (GeV/c2)2). Data collected during 1991 and 1992 in the DELPHI experiment at LEP are shown to agree well with predictions which included the non-perturbative vector meson dominance model in which the interacting photons are assumed to have converted into a vector meson (ϱ, ω or π), a quark-parton model which describes direct photon interactions and a QCD-based model which considers the photon to have quark and gluon structure functions. Five different parametrizations of these structure functions were used and the predictions compared with the data. This study confirms recent results from no-tag experiments in requiring a QCD-based component to successfully describe the data, indicating that the photon has a significant partonic content.
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Citations

Abreu, P., Adam, W., Adye, T., Agasi, E., Cortina Gil, E., DELPHI Collaboration, & et al. (1995). First evidence of hard scattering processes in single tagged gamma gamma collisions. Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics, 342(1–4), 402-416. https://doi.org/10.1016/0370-2693(94)01522-E (Original work published 1995)