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Open Access item Observation of Exclusive γγ Production in pp̅ Collisions at √s=1.96  TeV

Authors:Aaltonen, T.
Álvarez González, B.
Casal, Bruno
Gómez, G.
Gómez-Ceballos, Guillelmo
Palencia, Enrique
Rodrigo, Teresa
Scodellaro, Luca
Vila, Iván
Vilar, Rocío
Vizán, J.
CDF Collaboration
Issue Date:2012
Publisher:American Physical Society
Citation:Physical Review Letters 108(8): 081801 (2012)
Abstract:We have observed exclusive γγ production in proton-antiproton collisions at √s=1.96  TeV, using data from 1.11±0.07  fb-1 integrated luminosity taken by the Run II Collider Detector at Fermilab. We selected events with two electromagnetic showers, each with transverse energy ET>2.5  GeV and pseudorapidity |η|<1.0, with no other particles detected in -7.4<η<+7.4. The two showers have similar ET and azimuthal angle separation Δϕ∼π; 34 events have two charged particle tracks, consistent with the QED process pp̅ →p+e+e-+p̅ by two-photon exchange, while 43 events have no charged tracks. The number of these events that are exclusive π0π0 is consistent with zero and is <15 at 95% C.L. The cross section for pp̅ →p+γγ+p̅ with |η(γ)|<1.0 and ET(γ)>2.5  GeV is 2.48-0.35+0.40(stat)-0.51+0.40(syst)  pb.
Identifiers:doi: 10.1103/PhysRevLett.108.081801
issn: 0031-9007
e-issn: 1079-7114
Appears in Collections:(IFCA) Artículos

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