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
Yükleniyor...
Tarih
2018
Yazarlar
Dergi Başlığı
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Cilt Başlığı
Yayıncı
Springer Link
Erişim Hakkı
Özet
The process pp ? p?+??p(*), with ?+?? 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?=13s=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 ?+?? and 8 e+e? pairs with m(?+??) > 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 ?? collisions at the electroweak scale. This measurement also demonstrates that CT-PPS performs according to the design specifications..
Açıklama
Anahtar Kelimeler
Forward physics, Hadron-Hadron scattering, Photon production, proton-proton scattering
Kaynak
WoS Q Değeri
Q1
Scopus Q Değeri
Q2
