Title Measurement of top quark-antiquark pair production in association with a W or Z boson in pp collisions $\sqrt{s}$ =8 TeV Measurement of top quark-antiquark pair production in association with a W or Z boson in pp collisions $\sqrt{s}$ =8 TeV Author Khachatryan, V. Sirunyan, A.M. Tumasyan, A. Alderweireldt, S. Bansal, M. Bansal, S. Cornelis, T. de Wolf, E.A. Janssen, X. Knutsson, A. Luyckx, S. Ochesanu, S. Roland, B. Rougny, R. van de Klundert, M. van Haevermaet, H. Van Mechelen, P. Van Remortel, N. Van Spilbeeck, A. et al. Faculty/Department Faculty of Sciences. Physics Publication type article Publication 2014 Berlin , 2014 Subject Physics Source (journal) European physical journal : C : particles and fields. - Berlin Volume/pages 74(2014) :9 , 26 p. ISSN 1434-6044 1434-6044 Article Reference 3060 Carrier E-only publicatie Target language English (eng) Full text (Publishers DOI) Affiliation University of Antwerp Abstract A measurement of the cross section for the production of top quark-antiquark pairs (t (t) over bar) in association with a vector boson V (W or Z) in proton-proton collisions at root 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 mu) channels: a same-sign dilepton analysis targeting t (t) over barW events, and trilepton and four-lepton analyses designed for t (t) over barZ events. In the same-sign dilepton channel, the t (t) over barW cross section is measured as sigma(t (t) over barW) = 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 t (t) over barZ cross section, sigma(t (t) over barZ) = 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 t (t) over barV process is observed with a significance of 3.7 standard deviations from the combination of all three leptonic channels. Full text (open access) https://repository.uantwerpen.be/docman/irua/fdc6d1/9905.pdf E-info http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000350142400001&DestLinkType=RelatedRecords&DestApp=ALL_WOS&UsrCustomerID=ef845e08c439e550330acc77c7d2d848 http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000350142400001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=ef845e08c439e550330acc77c7d2d848 http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000350142400001&DestLinkType=CitingArticles&DestApp=ALL_WOS&UsrCustomerID=ef845e08c439e550330acc77c7d2d848 Handle