Measurement of top quark antiquark pair production in association with aW or Z boson in pp collisions at root s 8 TeV
Yazarlar (1)
Doç. Dr. Mustafa Numan BAKIRCI Tokat Gaziosmanpaşa Üniversitesi, Türkiye
Makale Türü Açık Erişim Özgün Makale (SSCI, AHCI, SCI, SCI-Exp dergilerinde yayınlanan tam makale)
Dergi Adı European Physical Journal C (Q4)
Dergi ISSN 1434-6044 Wos Dergi Scopus Dergi
Dergi Tarandığı Indeksler SCI
Makale Dili İngilizce Basım Tarihi 01-2014
Cilt / Sayı / Sayfa 74 / 9 / – DOI 10.1140/epjc/s10052-014-3060-7
UAK Araştırma Alanları
Yüksek Enerji ve Parçacık Fiziği
Özet
A measurement of the cross section for the production of top quark-antiquark pairs (t (t) over bar) in association with a vector boson V (W or Z) in proton-proton collisions at root 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 t (t) over barW events, and trilepton and four-lepton analyses designed for t (t) over barZ events. In the same-sign dilepton channel, the t (t) over barW cross section is measured as sigma(t (t) over barW) = 170(-80)(+90) (stat) +/- 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 t (t) over barZ cross section, sigma(t (t) over barZ) = 200(-70)(+80) (stat)(-30)(+40) (syst)fb(-1), 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 t (t) over barV process is observed with a significance of 3.7 standard deviations from the combination of all three leptonic channels.
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