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  • Search for Exclusive {gamma...
    Aaltonen, T.; Maki, T.; Mehtala, P.; Orava, R.; Osterberg, K.; Saarikko, H.; Remortel, N. van; Abulencia, A.; Budd, S.; Ciobanu, C. I.; Errede, D.; Errede, S.; Gerberich, H.; Grundler, U.; Junk, T. R.; Kraus, J.; Marino, C. P.; Pitts, K.; Rogers, E.; Taffard, A.

    Physical review letters, 12/2007, Letnik: 99, Številka: 24
    Journal Article

    We have searched for exclusive {gamma}{gamma} production in proton-antiproton collisions at {radical}(s)=1.96 TeV, using 532 pb{sup -1} of integrated luminosity taken by the run II Collider Detector at Fermilab. The event signature requires two electromagnetic showers, each with transverse energy E{sub T}>5 GeV and pseudorapidity |{eta}|<1.0, with no other particles detected in the event. Three candidate events are observed. We discuss the consistency of the three events with {gamma}{gamma}, {pi}{sup 0}{pi}{sup 0}, or {eta}{eta} production. The probability that other processes fluctuate to {>=}3 events is 1.7x10{sup -4}. An upper limit on the cross section of pp{yields}p+{gamma}{gamma}+p production is set at 410 fb with 95% confidence level.