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Observation of proton-tagged, central (semi)exclusive production of high-mass lepton pairs in pp collisions at 13 TeV with the CMS-TOTEM precision proton spectrometer

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    0502336 - FZÚ 2019 RIV US eng J - Journal Article
    Sirunyan, A.M. - Tumasyan, A. - Adam, W. - Kašpar, Jan - Kundrát, Vojtěch - Lokajíček, Miloš V. - Procházka, Jiří … Total 2357 authors
    Observation of proton-tagged, central (semi)exclusive production of high-mass lepton pairs in pp collisions at 13 TeV with the CMS-TOTEM precision proton spectrometer.
    Journal of High Energy Physics. Roč. 2018, č. 7 (2018), s. 1-45, č. článku 153. ISSN 1029-8479. E-ISSN 1029-8479
    Institutional support: RVO:68378271
    Keywords : forward physics * proton-proton scattering * photon-production
    OECD category: Particles and field physics
    Impact factor: 5.833, year: 2018

    The process pp → pℓ + ℓ − p (*) , with ℓ + ℓ − a muon or an electron pair produced at midrapidity with mass larger than 110 GeV, has been observed for the first time at the LHC in pp collisions at s=13 TeV. One of the two scattered protons is measured in the CMS-TOTEM precision proton spectrometer (CT-PPS), which operated for the first time in 2016. The second proton either remains intact or is excited and then dissociates into a low-mass state p * , which is undetected. The measurement is based on an integrated luminosity of 9.4 fb −1 collected during standard, high-luminosity LHC operation. A total of 12 μ + μ − and 8 e + e − pairs with m(ℓ + ℓ − ) > 110 GeV, and matching forward proton kinematics, are observed, with expected backgrounds of 1.49 ± 0.07 (stat) ± 0.53 (syst) and 2.36 ± 0.09 (stat) ± 0.47 (syst), respectively. This corresponds to an excess of more than five standard deviations over the expected background. The present result constitutes the first observation of proton-tagged γγ collisions at the electroweak scale. This measurement also demonstrates that CT-PPS performs according to the design specifications.
    Permanent Link: http://hdl.handle.net/11104/0294282

     
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