Search for exclusive or semi-exclusive photon pair production and observation of exclusive and semi-exclusive electron pair production in pp collisions at sqrt(s) = 7 TeV

Understand

A search for exclusive or semi-exclusive photon pair production, pp to p(*) + photon pair + p(*) (where p(*) stands for a diffractively-dissociated proton), and the observation of exclusive and semi-exclusive electron pair production, pp to p(*) + ee + p(*), in proton-proton collisions at sqrt(s) = 7 TeV, are presented.

• The analysis is based on a data sample corresponding to an integrated luminosity of 36 inverse picobarns recorded by the CMS experiment at the LHC at low instantaneous luminosities.
• Candidate photon pair or electron pair events are selected by requiring the presence of two photons or a positron and an electron, each with transverse energy ET > 5.5 GeV and pseudorapidity abs(eta) < 2.5, and no other particles in the region abs(eta) < 5.2.
• No exclusive or semi-exclusive diphoton candidates are found in the data.