Measurement of the production cross-section of a single top quark in association with a W boson at 8TeV with the ATLAS experiment Aad, G. Aguilar Saavedra, Juan Antonio Atlas Collaboration, / Hadron-Hadron scattering Top physics The cross-section for the production of a single top quark in association with a W boson in proton-proton collisions at √s = 8TeV is measured. The dataset corresponds to an integrated luminosity of 20.3 fb−1, collected by the ATLAS detector in 2012 at the Large Hadron Collider at CERN. Events containing two leptons and one central b-jet are selected. The W t signal is separated from the backgrounds using boosted decision trees, each of which combines a number of discriminating variables into one classifier. Production of W t events is observed with a significance of 7.7σ. The cross-section is extracted in a profile likelihood fit to the classifier output distributions. The W t cross-section, inclusive of decay modes, is measured to be 23.0 ± 1.3(stat.) + 3.2 − 3.5 (syst.)±1.1(lumi.) pb. The measured cross-section is used to extract a value for the CKM matrix element |V tb | of 1.01 ± 0.10 and a lower limit of 0.80 at the 95% confidence level. The cross-section for the production of a top quark and a W boson is also measured in a fiducial acceptance requiring two leptons with p T > 25 GeV and |η| < 2.5, one jet with p T > 20 GeV and |η| < 2.5, and E miss T  > 20 GeV, including both W t and top-quark pair events as signal. The measured value of the fiducial cross-section is 0.85 ± 0.01(stat.) + 0.07 − 0.07 (syst.)±0.03(lumi.) pb. 2024-10-16T10:18:19Z 2024-10-16T10:18:19Z 2016-01-11 journal article Aad, G. & Aguilar Saavedra, J.A. & ATLAS collaboration. J. High Energ. Phys. 2016, 64 (2016). [https://doi.org/10.1007/JHEP01(2016)064] https://hdl.handle.net/10481/96009 10.1007/JHEP01(2016)064 eng http://creativecommons.org/licenses/by/4.0/ open access Atribución 4.0 Internacional Springer