We have observed exclusive γγ production in proton-antiproton collisions at √s=1.96TeV, using data from 1.11±0.07fb -1 integrated luminosity taken by the Run II Collider Detector at Fermilab. We selected events with two electromagnetic showers, each with transverse energy E T>2.5GeV and pseudorapidity |η|<1.0, with no other particles detected in -7.4<+7.4. The two showers have similar E T and azimuthal angle separation Δψ∼π; 34 events have two charged particle tracks, consistent with the QED process pp̄→p+e +e -+p̄ 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 pp̄→p+γγ+p̄ with |η(γ)|<1.0 and E T(γ)>2.5GeV is 2.48-0.35+0.40(stat)-0.51+0.40(syst)pb. © 2012 American Physical Society.

Observation of exclusive γγ production in pp̄ collisions at √s=1.96TeV

Sforza F.;
2012-01-01

Abstract

We have observed exclusive γγ production in proton-antiproton collisions at √s=1.96TeV, using data from 1.11±0.07fb -1 integrated luminosity taken by the Run II Collider Detector at Fermilab. We selected events with two electromagnetic showers, each with transverse energy E T>2.5GeV and pseudorapidity |η|<1.0, with no other particles detected in -7.4<+7.4. The two showers have similar E T and azimuthal angle separation Δψ∼π; 34 events have two charged particle tracks, consistent with the QED process pp̄→p+e +e -+p̄ 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 pp̄→p+γγ+p̄ with |η(γ)|<1.0 and E T(γ)>2.5GeV is 2.48-0.35+0.40(stat)-0.51+0.40(syst)pb. © 2012 American Physical Society.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11567/970626
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