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

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 pseud...

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Detalles Bibliográficos
Autores: Aaltonen, T., Álvarez González, B., Casal, Bruno, Gómez, Gervasio, Palencia, Enrique, Rodrigo Anoro, Teresa, Scodellaro, Luca, Vila, Iván, Vilar Cortabitarte, R., Vizán, J., CDF Collaboration
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2012
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/52034
Acceso en línea:http://hdl.handle.net/10261/52034
Access Level:acceso abierto
Palabra clave:ddc:500.2
Descripción
Sumario: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.