A measurement of the cross section for the production of top quark–antiquark pairs (tt¯) in association with a vector boson V (W or Z) in proton-proton collisions at √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 μ) channels: a same-sign dilepton analysis targeting tt¯W events, and trilepton and four-lepton analyses designed for (Formula presented.) events. In the same-sign dilepton channel, the (Formula presented.) cross section is measured as (Formula presented.), 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 (Formula presented.) cross section, (Formula presented.), 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 (Formula presented.) process is observed with a significance of 3.7 standard deviations from the combination of all three leptonic channels.

The CMS Collaboration, N., Khachatryan, V., Sirunyan, A., Tumasyan, A., Adam, W., Bergauer, T., et al. (2014). Measurement of top quark–antiquark pair production in association with a W or Z boson in pp collisions at √s = 8 TeV. THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS, 74(9), 3060 [10.1140/epjc/s10052-014-3060-7].

Measurement of top quark–antiquark pair production in association with a W or Z boson in pp collisions at √s = 8 TeV

DINARDO, MAURO EMANUELE;FIORENDI, SARA;GEROSA, RAFFAELE ANGELO;GHEZZI, ALESSIO;GOVONI, PIETRO;LUCCHINI, MARCO TOLIMAN;MANZONI, RICCARDO ANDREA;MARTELLI, ARABELLA;MARZOCCHI, BADDER;MORONI, LUIGI;PAGANONI, MARCO;RAGAZZI, STEFANO;TABARELLI DE FATIS, TOMMASO;Branca, A;De Guio, F;
2014

Abstract

A measurement of the cross section for the production of top quark–antiquark pairs (tt¯) in association with a vector boson V (W or Z) in proton-proton collisions at √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 μ) channels: a same-sign dilepton analysis targeting tt¯W events, and trilepton and four-lepton analyses designed for (Formula presented.) events. In the same-sign dilepton channel, the (Formula presented.) cross section is measured as (Formula presented.), 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 (Formula presented.) cross section, (Formula presented.), 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 (Formula presented.) process is observed with a significance of 3.7 standard deviations from the combination of all three leptonic channels.
Articolo in rivista - Articolo scientifico
Engineering (miscellaneous); Physics and Astronomy (miscellaneous)
English
2014
74
9
3060
3060
open
The CMS Collaboration, N., Khachatryan, V., Sirunyan, A., Tumasyan, A., Adam, W., Bergauer, T., et al. (2014). Measurement of top quark–antiquark pair production in association with a W or Z boson in pp collisions at √s = 8 TeV. THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS, 74(9), 3060 [10.1140/epjc/s10052-014-3060-7].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/154055
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