Naslov
Measurement of associated production of vector bosons and top quark-antiquark pairs at sqrt(s) = 7 TeV

Autori
Chatrchyan, S. ; ... ; Godinović, Nikola ; Lelas, Damir ; Pleština, Roko ; Polić, Dunja ; Puljak, Ivica ; Antunović, Željko ; Kovač, Marko ; Brigljević, Vuko ; Đurić, Senka ; Kadija, Krešo ; Luetić, Jelena ; Mekterović, Darko ; Morović, Srećko ; Tikvica, Lucija ; ... ; Swanson, J.

Izvornik
Physical Review Letters (0031-9007) 110 (2013); 172002-1

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
LHC; CMS; top quark; vector bosons; associated production

Sažetak
The first measurement of vector-boson production associated with a top quark-antiquark pair in proton-proton collisions at sqrt(s) = 7 TeV is presented. The results are based on a data set corresponding to an integrated luminosity of 5.0 inverse femtobarms, recorded by the CMS detector at the LHC in 2011. The measurement is performed in two independent channels through a trilepton analysis of t t-bar Z events and a same-sign dilepton analysis of t t-bar V (V = W or Z) events. In the trilepton channel a direct measurement of the t t-bar Z cross section sigma(t t-bar Z) = 0.28 +0.14/-0.11 (stat) +0.06/-0.03 (syst) pb is obtained. In the dilepton channel a measurement of the t t-bar V cross section yields sigma(t t-bar V) = 0.43 +0.17/-0.15 (stat) +0.09/-0.07 (syst) pb. These measurements have a significance, respectively, of 3.3 and 3.0 standard deviations from the background hypotheses and are compatible, within uncertainties, with the corresponding next-to- leading order predictions of 0.137 +0.012/-0.016 and 0.306 +0.031/-0.053 pb.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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