Title Search for exclusive or semi-exclusive $\gamma\gamma$ production and observation of exclusive and semi-exclusive $e^{+}e^{-}$ production in pp collisions $\sqrt{s}=7TeV$Search for exclusive or semi-exclusive $\gamma\gamma$ production and observation of exclusive and semi-exclusive $e^{+}e^{-}$ production in pp collisions $\sqrt{s}=7TeV$ Author Chatrchyan, S. Khachatryan, V. Sirunyan, A. M. Bansal, S. Cornelis, T. de Wolf, E.A. Janssen, X. Luyckx, S. Mucibello, L. Roland, B. Rougny, R. Selvaggi, M. van Haevermaet, H. Van Mechelen, P. Van Remortel, N. Van Spilbeeck, A. et al. Faculty/Department Faculty of Sciences. Physics Research group Elementary Particle Physics Publication type article Publication 2012Bristol, 2012 Subject Physics Source (journal) Journal of high energy physics. - Bristol Volume/pages (2012):11, p. 1-35 ISSN 1126-6708 1029-8479 Article Reference 080 Carrier E-only publicatie Target language English (eng) Full text (Publishers DOI) Affiliation University of Antwerp Abstract A search for exclusive or semi-exclusive gamma gamma production, pp -> p(()*()) + gamma gamma + 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 root s = 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 gamma gamma 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 vertical bar eta vertical bar < 2.5, and no other particles in the region vertical bar eta vertical bar < 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(()*()) + gamma gamma + 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. Full text (open access) https://repository.uantwerpen.be/docman/irua/ed9290/5073.pdf E-info http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000312198500015&DestLinkType=RelatedRecords&DestApp=ALL_WOS&UsrCustomerID=ef845e08c439e550330acc77c7d2d848 http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000312198500015&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=ef845e08c439e550330acc77c7d2d848 http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000312198500015&DestLinkType=CitingArticles&DestApp=ALL_WOS&UsrCustomerID=ef845e08c439e550330acc77c7d2d848 Handle