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# Measurement of the t t ¯ W $$t\overline{t}W$$ and t t ¯ Z $$t\overline{t}Z$$ production cross sections in pp collisions at √s = 8 TeV with the ATLAS detector

CollaborationWith : Ancu, Lucian Stefan / Bell, William / Benhar Noccioli, Eleonora / Bilbao De Mendizabal, Javier / Calace, Noemi / Clark, Allan Geoffrey / Coccaro, Andrea / Delitzsch, Chris Malena / Della Volpe, Domenico / Ferrere, Didier / Gadomski, Szymon / Golling, Tobias / Gonzalez Sevilla, Sergio / Gramling, Johanna Léna / Guescini, Francesco / Iacobucci, Giuseppe / Katre, Akshay / Mermod, Philippe / Miucci, Antonio / Muenstermann, Daniel / Nessi, Marzio / Paolozzi, Lorenzo / Picazio, Attilio / Ristic, Branislav / Schramm, Steven / Tykhonov, Andrii / Vallecorsa, Sofia / Wu, Xin
Published in Journal of High Energy Physics. 2015, vol. 1511, p. 172-220
Collection Open Access - SCOAP3
Abstract The production cross sections of top-quark pairs in association with massive vector bosons have been measured using data from pp collisions at √s = 8 TeV. The dataset corresponds to an integrated luminosity of 20.3 fb −1 collected by the ATLAS detector in 2012 at the LHC. Final states with two, three or four leptons are considered. A fit to the data considering the t t ¯ W $$t\overline{t}W$$ and t t ¯ Z $$t\overline{t}Z$$ processes simultaneously yields a significance of 5.0 σ (4.2 σ ) over the background-only hypothesis for t t ¯ W $$t\overline{t}W$$ ( t t ¯ Z $$t\overline{t}Z$$ ) production. The measured cross sections are σ t t ¯ W = 369 − 91 + 100 $${\sigma}_{t\overline{t}W}={369}_{-91}^{+100}$$ fb and σ t t ¯ Z = 176 − 52 + 58 $${\sigma}_{t\overline{t}Z}={176}_{-52}^{+58}$$ fb. The background-only hypothesis with neither t t ¯ W $$t\overline{t}W$$ nor t t ¯ Z $$t\overline{t}Z$$ production is excluded at 7.1 σ . All measurements are consistent with next-to-leading-order calculations for the t t ¯ W $$t\overline{t}W$$ and t t ¯ Z $$t\overline{t}Z$$ processes.
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arXiv: 1509.05276
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ATLAS COLLABORATION. Measurement of the t t ¯ W $$t\overline{t}W$$ and t t ¯ Z $$t\overline{t}Z$$ production cross sections in pp collisions at √s = 8 TeV with the ATLAS detector. In: Journal of High Energy Physics, 2015, vol. 1511, p. 172-220. https://archive-ouverte.unige.ch/unige:79083

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