2026-10-18T23:59:40Zhttps://ebyu-rdlopen.rawdatalibrary.net/oai/requestoai:ebyu-rdlopen.rawdatalibrary.net:ebyu/156032026-10-18T20:30:27Zopenairedrivercom_ebyu_10000col_ebyu_10001Search for exclusive or semi-exclusive γ γ production and observation of exclusive and semi-exclusive e+e- production in pp collisions at √ s = 7 TeVChatrchyan, S.Khachatryan, V.Sirunyan, A.M.Tumasyan, A.Adam, W.Bergauer, T.Dragicevic, M.Erö, J.Fabjan, C.Friedl, M.Frühwirth, R.Ghete, V.M.Hammer, J.Hörmann, N.Hrubec, J.Jeitler, M.Kiesenhofer, W.Knünz, V.Krammer, M.Liko, D.Mikulec, I.Pernicka, M.Rahbaran, B.Rohringer, C.Rohringer, H.Schöfbeck, R.Strauss, J.Taurok, A.Wagner, P.Waltenberger, W.Walzel, G.Widl, E.Wulz, C.-E.Mossolov, V.Shumeiko, N.Suarez Gonzalez, J.Bansal, S.Cornelis, T.De Wolf, E.A.Janssen, X.Luyckx, S.Maes, T.Mucibello, L.Ochesanu, S.Roland, B.Rougny, R.Selvaggi, M.Staykova, Z.Van Haevermaet, H.Van Mechelen, P.Hadron-Hadron ScatteringA 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.Springer Verlag2012Articlehttps://rdlopen.rawdatalibrary.net/r/ebyu/15603https://doi.org/10.1007/jhep11(2012)0801126-6708enJournal of High Energy Physicsinfo:eu-repo/semantics/openAccessinfo:eu-repo/semantics/articlehttps://ebyu-rdlopen.rawdatalibrary.net/tr/items/ebyu/15603