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| CMS-TOP-12-036 ; CERN-PH-EP-2014-136 | ||
| Measurement of top quark-antiquark pair production in association with a W or Z boson in pp collisions at $\sqrt{s}$ = 8 TeV | ||
| CMS Collaboration | ||
| 30 June 2014 | ||
| Eur. Phys. J. C 74 (2014) 3060 | ||
| Abstract: A measurement of the cross section for the production of top quark-antiquark pairs ($\mathrm{ t\bar{t} }$) in association with a vector boson V (W or Z) in proton-proton collisions at $\sqrt{s}$ = 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 $\mathrm{ t\bar{t}W }$ events, and trilepton and four-lepton analyses designed for $\mathrm{ t\bar{t}Z}$ events. In the same-sign dilepton channel, the $\mathrm{ t\bar{t}W}$ cross section is measured as $\sigma_{\mathrm{ t\bar{t}W}}$ = 170 $^{+90}_{-80}$ (stat) $\pm$ 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 $\mathrm{ t\bar{t}Z }$ cross section, $\sigma_{\mathrm{ t\bar{t}Z} } =$ 200 $^{+80}_{-70}$ (stat) $^{+40}_{-30}$ (syst) fb, is obtained with a significance of 3.2 standard deviations. The measured cross sections are compatible with standard model predictions within their experimental uncertainties. The inclusive $\mathrm{ t\bar{t}V }$ process is observed with a significance of 3.7 standard deviations from the combination of all three leptonic channels. | ||
| Links: e-print arXiv:1406.7830 [hep-ex] (PDF) ; CDS record ; inSPIRE record ; Public twiki page ; CADI line (restricted) ; | ||
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