# Measurement of the cross section for top quark pair production in association with a W or Z boson in proton-proton collisions at $\sqrt{s}=13$ TeV

CMS Collaboration; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Asilar, E.; Bergauer, T.; Brandstetter, J.; Brondolin, E.; Dragicevic, M.; Erö, J.; Escalante Del Valle, A.; Flechl, M.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Grossmann, J.; Hrubec, J.; Jeitler, M.; König, A.; Krammer, N.; ... mehr

Abstract:
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(tt¯W)=0.77+0.12−0.11(stat)+0.13−0.12(syst)pb and σ(tt¯Z)=0.99+0.09−0.08(stat)+0.12−0.10(syst)pb. The expected (observed) signal significance for the tt¯W production in same-sign dilepton channel is found to be 4.5 (5.3) standard deviations, while for the tt¯Z 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 tt¯W and tt¯Z production.

 Zugehörige Institution(en) am KIT Institut für Experimentelle Kernphysik (IEKP) Publikationstyp Zeitschriftenaufsatz Jahr 2018 Sprache Englisch Identifikator ISSN: 1029-8479 urn:nbn:de:swb:90-862027 KITopen-ID: 1000086202 Erschienen in Journal of high energy physics Band 2018 Heft 8 Seiten Article: 11 Bemerkung zur Veröffentlichung Gefördert durch SCOAP3 Vorab online veröffentlicht am 03.08.2018 Schlagworte Hadron-Hadron scattering (experiments); Top physics Nachgewiesen in Scopus
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