Abstract: A search for exclusive or semi-exclusive ?? production, pp ? p(*) + ?? + p(*) (where p* stands for a diffractively-dissociated proton), and the observation of exclusive and semi-exclusive e+e? production, pp ? p(*) +?e+e? + p(*), in proton-proton collisions at s?=7s=7 TeV, are presented. The analysis is based on a data sample corresponding to an integrated luminosity of 36 pb?1 recorded by the CMS experiment at the LHC at low instantaneous luminosities. Candidate ?? or e+e? events are selected by requiring the presence of two photons or a positron and an electron, each with transverse energy E T? >?5.5 GeV and pseudorapidity |?| < 2.5, and no other particles in the region |?| < 5.2. No exclusive or semi-exclusive diphoton candidates are found in the data. An upper limit on the cross section for the reaction pp ? p(*) + ?? + p(*), within the above kinematic selections, is set at 1.18 pb at 95% confidence level. Seventeen exclusive or semi-exclusive dielectron candidates are observed, with an estimated background of 0.85?±?0.28 (stat.) events, in agreement with the QED-based prediction of 16.3?±?1.3 (syst.) events.

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