2017/11/30 by A. M. Sirunyan, CMS Collaboration, A. Tumasyan +98 · 1 citation
Physics and Astronomy · #High-Energy Particle Collisions Research #Materials science #Particle Detector Development and Performance #Particle physics theoretical and experimental studies #Physics #hep-ex
paper · pdf · doi:10.1007/jhep08(2018)011
published as JHEP 08 (2018) 011 · Replaced with the published version. Added the journal reference and the DOI. All the figures and tables, including additional supplementary figures, can be found at http://cms-results.web.cern.ch/cms-results/public-results/publications/TOP-17-005 (CMS Public Pages)
openalex created_date 2017/12/04 · openalex publication_date 2018/08/01 · arxiv created 2018/08/14 · arxiv updated 2018/08/16 · openalex updated_date 2026/08/06
A bstract A measurement is performed of the cross section of top quark pair production in association with a W or Z boson using proton-proton collisions at a center-of-mass energy of 13 TeV at the LHC. The data sample corresponds to an integrated luminosity of 35.9 fb −1 , collected by the CMS experiment in 2016. The measurement is performed in the same-sign dilepton, three- and four-lepton final states. The production cross sections are measured to be σ (ttW)=0.77-0.11+0.12(stat)-0.12+0.13(syst)pb <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>σ</mml:mi> <mml:mfenced> <mml:mrow> <mml:mi>t</mml:mi> <mml:mover> <mml:mi>t</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> <mml:mi>W</mml:mi> </mml:mrow> </mml:mfenced> <mml:mo>=</mml:mo> <mml:msubsup> <mml:mn>0.77</mml:mn> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.11</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.12</mml:mn> </mml:mrow> </mml:msubsup> <mml:msubsup> <mml:mfenced> <mml:mi>stat</mml:mi> </mml:mfenced> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.12</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.13</mml:mn> </mml:mrow> </mml:msubsup> <mml:mfenced> <mml:mi>syst</mml:mi> </mml:mfenced> <mml:mi>p</mml:mi> <mml:mi>b</mml:mi> </mml:math> and σ (ttZ)=0.99-0.08+0.09(stat)-0.10+0.12(syst)pb <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>σ</mml:mi> <mml:mfenced> <mml:mrow> <mml:mi>t</mml:mi> <mml:mover> <mml:mi>t</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> <mml:mi>Z</mml:mi> </mml:mrow> </mml:mfenced> <mml:mo>=</mml:mo> <mml:msubsup> <mml:mn>0.99</mml:mn> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.08</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.09</mml:mn> </mml:mrow> </mml:msubsup> <mml:msubsup> <mml:mfenced> <mml:mi>stat</mml:mi> </mml:mfenced> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.10</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.12</mml:mn> </mml:mrow> </mml:msubsup> <mml:mfenced> <mml:mi>syst</mml:mi> </mml:mfenced> <mml:mi>p</mml:mi> <mml:mi>b</mml:mi> </mml:math> . The expected (observed) signal significance for the ttW <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>t</mml:mi> <mml:mover> <mml:mi>t</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> <mml:mi>W</mml:mi> </mml:math> production in same-sign dilepton channel is found to be 4.5 (5.3) standard deviations, while for the ttZ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>t</mml:mi> <mml:mover> <mml:mi>t</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> <mml:mi>Z</mml:mi> </mml:math> production in three- and four-lepton channels both the expected and the observed significances are found to be in excess of 5 standard deviations. The results are in agreement with the standard model predictions and are used to constrain the Wilson coefficients for eight dimension-six operators describing new interactions that would modify ttW <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>t</mml:mi> <mml:mover> <mml:mi>t</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> <mml:mi>W</mml:mi> </mml:math> and ttZ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>t</mml:mi> <mml:mover> <mml:mi>t</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> <mml:mi>Z</mml:mi> </mml:math> production.