Search for exclusive or semi-exclusive γ γ production and observation of exclusive and semi-exclusive e+e- production in pp collisions at √ s = 7 TeV

The CMS Collaboration

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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.

Original languageEnglish
Article number080
JournalJournal of High Energy Physics
Volume2012
Issue number11
DOIs
Publication statusPublished - 2012 Jan 1

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collisions
protons
luminosity
confidence
positrons
kinematics
cross sections
photons
predictions
electrons
energy

Keywords

  • Hadron-Hadron Scattering

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

Cite this

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title = "Search for exclusive or semi-exclusive γ γ production and observation of exclusive and semi-exclusive e+e- production in pp collisions at √ s = 7 TeV",
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.",
keywords = "Hadron-Hadron Scattering",
author = "{The CMS Collaboration} and S. Chatrchyan and V. Khachatryan and Sirunyan, {A. M.} and A. Tumasyan and W. Adam and T. Bergauer and M. Dragicevic and J. Er{\"o} and C. Fabjan and M. Friedl and R. Fr{\"u}hwirth and Ghete, {V. M.} and J. Hammer and N. H{\"o}rmann and J. Hrubec and M. Jeitler and W. Kiesenhofer and V. Kn{\"u}nz and M. Krammer and D. Liko and I. Mikulec and M. Pernicka and B. Rahbaran and C. Rohringer and H. Rohringer and R. Sch{\"o}fbeck and J. Strauss and A. Taurok and P. Wagner and W. Waltenberger and G. Walzel and E. Widl and Wulz, {C. E.} and V. Mossolov and N. Shumeiko and {Suarez Gonzalez}, J. and S. Bansal and T. Cornelis and {De Wolf}, {E. A.} and X. Janssen and S. Luyckx and T. Maes and L. Mucibello and S. Ochesanu and B. Roland and R. Rougny and M. Selvaggi and Z. Staykova and {Van Haevermaet}, H. and Su-Yong Choi",
year = "2012",
month = "1",
day = "1",
doi = "10.1007/JHEP11(2012)080",
language = "English",
volume = "2012",
journal = "Journal of High Energy Physics",
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T1 - Search for exclusive or semi-exclusive γ γ production and observation of exclusive and semi-exclusive e+e- production in pp collisions at √ s = 7 TeV

AU - The CMS Collaboration

AU - Chatrchyan, S.

AU - Khachatryan, V.

AU - Sirunyan, A. M.

AU - Tumasyan, A.

AU - Adam, W.

AU - Bergauer, T.

AU - Dragicevic, M.

AU - Erö, J.

AU - Fabjan, C.

AU - Friedl, M.

AU - Frühwirth, R.

AU - Ghete, V. M.

AU - Hammer, J.

AU - Hörmann, N.

AU - Hrubec, J.

AU - Jeitler, M.

AU - Kiesenhofer, W.

AU - Knünz, V.

AU - Krammer, M.

AU - Liko, D.

AU - Mikulec, I.

AU - Pernicka, M.

AU - Rahbaran, B.

AU - Rohringer, C.

AU - Rohringer, H.

AU - Schöfbeck, R.

AU - Strauss, J.

AU - Taurok, A.

AU - Wagner, P.

AU - Waltenberger, W.

AU - Walzel, G.

AU - Widl, E.

AU - Wulz, C. E.

AU - Mossolov, V.

AU - Shumeiko, N.

AU - Suarez Gonzalez, J.

AU - Bansal, S.

AU - Cornelis, T.

AU - De Wolf, E. A.

AU - Janssen, X.

AU - Luyckx, S.

AU - Maes, T.

AU - Mucibello, L.

AU - Ochesanu, S.

AU - Roland, B.

AU - Rougny, R.

AU - Selvaggi, M.

AU - Staykova, Z.

AU - Van Haevermaet, H.

AU - Choi, Su-Yong

PY - 2012/1/1

Y1 - 2012/1/1

N2 - 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.

AB - 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.

KW - Hadron-Hadron Scattering

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U2 - 10.1007/JHEP11(2012)080

DO - 10.1007/JHEP11(2012)080

M3 - Article

VL - 2012

JO - Journal of High Energy Physics

JF - Journal of High Energy Physics

SN - 1126-6708

IS - 11

M1 - 080

ER -