Measurement of the single-top-quark t-channel cross section in pp collisions at = 7 TeV using a multivariate analysis

Abstract

Electroweak top-quark production offers a unique access to search for new physics phenomena. The measurement of the t-channel cross section allows to determine the Cabibbo-Kobayashi-Maskawa matrix element |Vtb| with high precision and without assuming its unitarity. We present the precise measurement of the t-channel single-top-quark production cross section with a multivariate analysis. Data collected with the CMS experiment in proton-proton collisions at a center-of-mass energy of 7 TeV, corresponding to 1.17 fb−1 for muon final states and 1.56 fb−1 for electron final states, are used for this measurement. The measured t-channel single-top-quark production cross section is 67.2 ± 6.1 pb, compatible with the approximate next-to-next-to-leading-order Standard Model prediction. The CKM matrix element |Vtb| is measured to be 1.020 ± 0.046 (meas.) ± 0.017 (theor.).