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.)− 3.5+ 3.2(syst.)±1.1(lumi.) pb. The measured cross-section is used to extract a value for the CKM matrix element |Vtb| 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 pT> 25 GeV and |η| < 2.5, one jet with pT> 20 GeV and |η| < 2.5, and ETmiss > 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.

Measurement of the production cross-section of a single top quark in association with a $W$ boson at 8 TeV with the ATLAS experiment / Aad, G., Abbott, B., Abdallah, J., Khalek, S.A., Abdinov, O., Aben, R., Abi, B., Abolins, M., Abouzeid, O.S., Abramowicz, H., Abreu, H., Abreu, R., Abulaiti, Y., Acharya, B.S., Adamczyk, L., Adams, D.L., Adelman, J., Adomeit, S., Adye, T., Agatonovic Jovin, T., et al.. - In: JOURNAL OF HIGH ENERGY PHYSICS. - ISSN 1126-6708. - STAMPA. - 01:(2016). [10.1007/JHEP01(2016)064]

Measurement of the production cross-section of a single top quark in association with a $W$ boson at 8 TeV with the ATLAS experiment

Artoni, G.;BAGNAIA, Paolo;BINI, Cesare;DE CECCO, Sandro;DI DOMENICO, Antonio;GAUZZI, Paolo;GENTILE, Simonetta;GIAGU, Stefano;Kado, M.;LACAVA, Francesco;LUCI, Claudio;MESSINA, Andrea;Policicchio, A.;
2016

Abstract

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.)− 3.5+ 3.2(syst.)±1.1(lumi.) pb. The measured cross-section is used to extract a value for the CKM matrix element |Vtb| 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 pT> 25 GeV and |η| < 2.5, one jet with pT> 20 GeV and |η| < 2.5, and ETmiss > 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.
2016
01 Pubblicazione su rivista::01a Articolo in rivista
Measurement of the production cross-section of a single top quark in association with a $W$ boson at 8 TeV with the ATLAS experiment / Aad, G., Abbott, B., Abdallah, J., Khalek, S.A., Abdinov, O., Aben, R., Abi, B., Abolins, M., Abouzeid, O.S., Abramowicz, H., Abreu, H., Abreu, R., Abulaiti, Y., Acharya, B.S., Adamczyk, L., Adams, D.L., Adelman, J., Adomeit, S., Adye, T., Agatonovic Jovin, T., et al.. - In: JOURNAL OF HIGH ENERGY PHYSICS. - ISSN 1126-6708. - STAMPA. - 01:(2016). [10.1007/JHEP01(2016)064]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/948227
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