2018/03/31 by CMS Collaboration, A. M. Sirunyan, TOTEM Collaboration +99 · 2 citations
Chemistry · Physics and Astronomy · #Analytical Chemistry (journal) #Astrophysics #Chemistry #Electron #Electroweak interaction #High-Energy Particle Collisions Research #Large Hadron Collider #Lepton #Luminosity #Muon #Nuclear physics #Particle Detector Development and Performance #Particle physics #Particle physics theoretical and experimental studies #Physics #Proton #Standard Model (mathematical formulation) #hep-ex
paper · pdf · doi:10.1007/jhep07(2018)153
published as JHEP 07 (2018) 153 · Replaced with published version. All figures and tables can be found at http://cms-results.web.cern.ch/cms-results/public-results/publications/PPS-17-001 (CMS Public Pages)
openalex created_date 2018/04/06 · openalex publication_date 2018/07/01 · arxiv created 2018/08/11 · arxiv updated 2018/08/14 · openalex updated_date 2026/08/06
A bstract The process pp → p ℓ + 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 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> <mml:mo>=</mml:mo> <mml:mn>13</mml:mn> </mml:math> 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.