Observation of tW production in the single-lepton channel in pp collisions at $$ \sqrt{s} $$ = 13 TeV

Abstract

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 $$ \sqrt{s} $$ s = 13 TeV is presented. The data correspond to an integrated luminosity of 36 fb−1 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 t$$ \overline{\mathrm{t}} $$ t ¯ 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.

One-loop squared amplitudes for hadronic tW production at next-to-next-to-leading order in QCD

“…tW -channel, as shown in the leading order (LO) Feynman diagrams in figure 1, can be used to probe the coupling between the W boson and the top quark, including the Cabibbo-Kobayashi-Maskawa matrix element V tb . The ATLAS and CMS collaborations at the CERN large hadron collider (LHC) have already observed the signal of this process based on the data accumulated at center-of-mass energies of 7, 8, 13 TeV [2][3][4][5][6][7][8][9][10]. So far, only the data recorded in 2016, corresponding to 35.9 fb −1 integrated luminosity, have been taken into account in the public analyses, and the uncertainty of the measured cross section is about 11% [11].…”

One-loop squared amplitudes for hadronic $tW$ production at next-to-next-to-leading order in QCD

“…tW -channel, as shown in the leading order (LO) Feynman diagrams in figure 1, can be used to probe the coupling between the W boson and the top quark, including the Cabibbo-Kobayashi-Maskawa matrix element V tb . The ATLAS and CMS collaborations at the CERN large hadron collider (LHC) have already observed the signal of this process based on the data accumulated at center-of-mass energies of 7, 8, 13 TeV [2][3][4][5][6][7][8][9][10]. So far, only the data recorded in 2016, corresponding to 35.9 fb −1 integrated luminosity, have been taken into account in the public analyses, and the uncertainty of the measured cross section is about 11% [11].…”

Analytic two-loop amplitudes for $tW$ production: leading color and light fermion-loop contributions

“…TeV [1][2][3][4]. More precise experimental results will be available in the near future after the launch of the Large Hadron Collider (LHC) Run-3.…”