@article{10902/2151,
year = {2012},
month = {2},
url = {http://hdl.handle.net/10902/2151},
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.},
publisher = {American Physical Society},
publisher = {Physical review letters, vol. 108, iss. 8, art. num. 081801 (2012)},
title = {Observation of Exclusive γγ Production in pp̅ Collisions at √s=1.96  TeV},
author = {Aaltonen, Timo Antero and Álvarez González, Bárbara and Amerio, Silvia and Amidei, Dante and Anastassov, Anton and Annovi, Alberto and Antos, Jaroslav and Apollinari, Giorgio and Casal Laraña, Bruno and Cuevas Maestro, Francisco Javier and Gómez Gramuglio, Gervasio and Palencia Cortezón, José Enrique and Rodrigo Anoro, Teresa and Ruiz Jimeno, Alberto and Scodellaro, Luca and Vila Álvarez, Iván  and Vilar Cortabitarte, Rocío and Vizán García, Jesús Manuel and Appel, Jeffrey A. and Albrow, Michael G.},
}