The early experiments on photon-photon collisions

  • G. Barbiellini
Session I
Part of the Lecture Notes in Physics book series (LNP, volume 134)


  1. 1)

    The fourth order QED calculation agrees with the experiment and the exact calculation differs from the equivalent photon approximation by less than 30%.

  2. 2)

    Two methods of seaparating YY events from annihilation events have been experimentally checked: the tagging of the forward e+e and no tagging. Both methods have been successful.

  3. 3)

    The first indication of hadron production from yy shows that the cross-section for γγ → ππ is not very different from the pointlike cross-section.

  4. 4)

    From the reaction γγ → nh an upper limit on η′ radiative decay has been derived: γη′→γγ ≤ 16 KeV, 95% C.L.L.



Storage Ring Hadron Production Annihilation Event Cerenkov Counter Energy Acceptance 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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    V.E. Balakin et al., Phys. Lett. 34B (1971).Google Scholar
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    G. Barbiellini et al., Phys. Rev. Lett. 32 (1974) 385.CrossRefGoogle Scholar
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    L. Paoluzi et al., Lett. Nuovo Cimento 10 (1976) 435.Google Scholar
  5. 5).
    R. Baldini et al., Phys. Lett. 86B (1979) 239.Google Scholar

Copyright information

© Springer-Verlag 1980

Authors and Affiliations

  • G. Barbiellini
    • 1
    • 2
  1. 1.Laboratori Nazionali INFNFrascatiItaly
  2. 2.CERNGenevaSwitzerland

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