Observation of exclusive electron-positron production in hadron-hadron collisions

Abstract

We present the first observation of exclusive e+e- production in hadron-hadron collisions, using pp̄ collision data at s=1.96TeV taken by the run II Collider Detector at Fermilab, and corresponding to an integrated luminosity of 532pb-1. We require the absence of any particle signatures in the detector except for an electron and a positron candidate, each with transverse energy ET>5GeV and pseudorapidity |η|<2. With these criteria, 16 events are observed compared to a background expectation of 1.9±0.3 events. These events are consistent in cross section and properties with the QED process pp̄→p+e+e-+p̄ through two-photon exchange. The measured cross section is 1.6-0.3+0.5(stat)±0.3(syst)pb. This agrees with the theoretical prediction of 1.71±0.01pb. © 2007 The American Physical Society.