Search for exclusive or semi-exclusive γγ production and observation of exclusive and semi-exclusive e+e− production in pp collisions at √s=7 TeV
Name
Chatrchyan2012_Article_SearchForExclusiveOrSemi-exclu.pdf
Description
Published version
Size
795.17 KB
Format
Adobe PDF
Checksum (MD5)
135f5cf6a6464308521e4ac734b1050d
Author(s)
The CMS Collaboration
Date Issued
2012
Journal
Journal of High Energy Physics
Publisher
Springer Science and Business Media LLC
Citation
Chatrchyan, S., et al. "Search for Exclusive or Semi-Exclusive Gamma Gamma Production and Observation of Exclusive and Semi-Exclusive E(+)E(-) Production in Pp Collisions at Root S=7 Tev." Journal of High Energy Physics 11 (2012): 35.
Version
Final published version
Abstract
A search for exclusive or semi-exclusive production, pp → p(*) +γ γ+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 = 7TeV, 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 γ γor e+e - 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 |η| < 2.5, and no other particles in the region |η| < 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(*) +γ γ+ 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. © SISSA 2012.
MIT Department
Massachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology. Laboratory for Nuclear Science
Terms of Use
Creative Commons Attribution 4.0 International license
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1007/JHEP11(2012)080
