The first measurement of vector-boson production associated with a top quark-antiquark pair in protonproton collisions at sqrt(s) 7 TeV is presented. The results are based on a data set corresponding to an integrated luminosity of 5:0 fb1, recorded by the CMS detector at the LHC in 2011. The measurement is performed in two independent channels through a trilepton analysis of ttZ events and a same-sign dilepton analysis of ttV (V = W or Z) events. In the trilepton channel a direct measurement of the ttZ cross section ttZ is obtained. In the dilepton channel a measurement of the ttV cross section yields ttV = 0:43þ0:17 0:15 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 0:137þ0:012 0:016 and 0:306þ0:031 0:053 pb.
Measurement of associated production of vector bosons and top quark-antiquark pairs in pp collisions at sqrt[s]=7 TeV
V. Sola;AMAPANE, Nicola Carlo;ARGIRO', Stefano;CASASSO, STEFANO;COSTA, Marco;MIGLIORE, Ernesto;MONACO, Vincenzo;MUSICH, MARCO;OBERTINO, Maria Margherita;PELLICCIONI, Mario;ROMERO, Alessandra;SACCHI, Roberto;SOLANO, Ada Maria;BELLAN, Riccardo;COVARELLI, Roberto;
2013-01-01
Abstract
The first measurement of vector-boson production associated with a top quark-antiquark pair in protonproton collisions at sqrt(s) 7 TeV is presented. The results are based on a data set corresponding to an integrated luminosity of 5:0 fb1, recorded by the CMS detector at the LHC in 2011. The measurement is performed in two independent channels through a trilepton analysis of ttZ events and a same-sign dilepton analysis of ttV (V = W or Z) events. In the trilepton channel a direct measurement of the ttZ cross section ttZ is obtained. In the dilepton channel a measurement of the ttV cross section yields ttV = 0:43þ0:17 0:15 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 0:137þ0:012 0:016 and 0:306þ0:031 0:053 pb.File | Dimensione | Formato | |
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PhysRevLett.110.172002.pdf
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