Observation of tW production in the single-lepton channel in pp collisions at ?s = 13 TeV

Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Chatterjee, S.; Dragicevic, M.; Escalante Del Valle, A.; Frühwirth, R.; Jeitler, M.; Krammer, N.; Lechner, L.; Liko, D.; Mikulec, I.; Paulitsch, P.; Pitters, F. M.; Schieck, J.; Schöfbeck, R.; Spanring, M.; Templ, S.; Waltenberger, W.; Wulz, C. E.; Chekhovsky, V.; Litomin, A.; Makarenko, V.; Darwish, M. R.; De Wolf, E. A.; Janssen, X.; Kello, T.; Lelek, A.; Rejeb Sfar, H.; Van Mechelen, P.; Van Putte, S.; Van Remortel, N.; Blekman, F.; Bols, E. S.; D'Hondt, J.; De Clercq, J.; Delcourt, M.; El Faham, H.; Lowette, S.; Moortgat, S.; Morton, A.; Müller, D.; Sahasransu, A. R.; Tavernier, S.; Van Doninck, W.; Van Mulders, P.; Beghin, D.; Bilin, B.; Clerbaux, B.; De Lentdecker, G.; Favart, L.; Grebenyuk, A.; Kalsi, A. K.; Lee, K.; Mahdavikhorrami, M.; Makarenko, I.; Moureaux, L.; Pétré, L.; Popov, A.; Postiau, N.; Starling, E.; Thomas, L.; Vanden Bemden, M.; Vander Velde, C.; Vanlaer, P.; Vannerom, D.; Wezenbeek, L.; Cornelis, T.; Dobur, D.; Knolle, J.; Lambrecht, L.; Mestdach, G.; Niedziela, M.; Roskas, C.; Samalan, A.; Skovpen, K.; Tytgat, M.; Verbeke, W.; Vermassen, B.; Vit, M.; Bethani, A.; Bruno, G.; Bury, F.; Caputo, C.; David, P.; Delaere, C.; Donertas, I. S.; Giammanco, A.; Jaffel, K.; Jain, Sa; Lemaitre, V.; Mondal, K.; Prisciandaro, J.; Taliercio, A.; Teklishyn, M.; Tran, T. T.; Vischia, P.; Wertz, S.; Alves, G. A.; Moscatelli, F.; Asenov, P.

doi:10.1007/JHEP11(2021)111

A measurement of the cross section of the associated production of a single top quark and a W boson in final states with a muon or electron and jets in proton-proton collisions at s = 13 TeV is presented. The data correspond to an integrated luminosity of 36 fb collected with the CMS detector at the CERN LHC in 2016. A boosted decision tree is used to separate the tW signal from the dominant tt ¯ background, whilst the subleading W+jets and multijet backgrounds are constrained using data-based estimates. This result is the first observation of the tW process in final states containing a muon or electron and jets, with a significance exceeding 5 standard deviations. The cross section is determined to be 89 ± 4 (stat) ± 12 (syst) pb, consistent with the standard model. [Figure not available: see fulltext.]