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URN: urn:nbn:de:swb:90-453172
DOI: 10.1140/epjc/s10052-014-3060-7

Measurement of top quark - antiquark pair production in association with a W or Z boson in pp collisions at $\sqrts$ = 8 TeV

The CMS Collaboration; Khachatryan, V.; Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Erö, J.; Fabjan, C.; Friedl, M.; Frühwirth, R.; Ghete, V.M.; Hartl, C.; Hörmann, N.; Hrubec, J.; Jeitler, M.; Kiesenhofer, W.; Knünz, V.; Krammer, M.; Krätschmer, I.; ... mehr

A measurement of the cross section for the production of top quark–antiquark pairs ( tt¯ ) in association with a vector boson V (W or Z) in proton-proton collisions at s=8 TeV is presented. The results are based on a dataset corresponding to an integrated luminosity of 19.5 fb -1 recorded with the CMS detector at the LHC. The measurement is performed in three leptonic (e and μ ) channels: a same-sign dilepton analysis targeting tt¯W events, and trilepton and four-lepton analyses designed for tt¯Z events. In the same-sign dilepton channel, the tt¯W cross section is measured as σtt¯W=170-80+90(stat)±70(syst)fb , corresponding to a significance of 1.6 standard deviations over the background-only hypothesis. Combining the trilepton and four-lepton channels, a direct measurement of the tt¯Z cross section, σtt¯Z=200-70+80(stat)-30+40(syst)fb-1 , is obtained with a significance of 3.1 standard deviations. The measured cross sections are compatible with standard model predictions within their experimental uncertainties. The inclusive tt¯V process is observed with a significance of 3.7 standard deviations ... mehr

Zugehörige Institution(en) am KIT Institut für Experimentelle Kernphysik (IEKP)
Publikationstyp Zeitschriftenaufsatz
Jahr 2014
Sprache Englisch
Identifikator ISSN: 1434-6044
KITopen ID: 1000045317
Erschienen in European Physical Journal C
Band 74
Heft 9
Seiten 1-26
Bemerkung zur Veröffentlichung Gefördert durch SCOAP3
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