Measurements of ttW differential cross sections and the leptonic charge asymmetry at $\sqrt{s}$ = 13 TeV

Abstract

Measurements of properties of top quark-antiquark pair production in association with a W boson in proton-proton collisions at a center-of-mass energy of 13 TeV are presented, using a data sample corresponding to an integrated luminosity of 138 fb$^{-1}$, recorded by the CMS experiment at the CERN LHC. Events are selected based on the presence of either two leptons with the same electric charge or three leptons, and multiple jets and b-tagged jets. We present measurements of differential production cross sections as a function of kinematic variables sensitive to different aspects of the process modeling, using a multivariate discriminator in the two-lepton selection region and a simple selection-based method in the three-lepton region. The normalized cross section measurements are generally consistent with the standard model expectations, while we observe larger values compared to the expectations in the absolute cross section measurements, consistent with previous inclusive cross section measurements. In addition, we measure the leptonic charge asymmetry of this process, obtaining an observed value of $A_\text{c}^{\ell}$ = $-$0.19 $^{+0.16}_{-0.18}$, consistent with the expectation of $-$0.085 $\pm$ 0.006 predicted by next-to-leading order simulations.

Figures (28)

• Figure 1: Examples of Feynman diagrams for $\ttbar\PW$ production: at LO (left) and one of the NLO diagrams introducing sizeable electroweak corrections (right).
• Figure 2: An overview of all control regions (CR) and signal regions (SR) used in the analysis.
• Figure 3: of the sub-leading lepton (left) and $\abs{\eta}$ of the subleading lepton (right), in a VR enriched with nonprompt leptons by applying requirements on the number of (-tagged) jets orthogonal to the SR, for data (points) and predictions (filled histograms) after the fit to the data in the SR and CR as described in Section \ref{['sec:differential']} for the tight lepton selection. The lower panels show the ratio of the data to the sum of the postfit predictions (points) and the ratio of the data to the prefit predictions (red line). The vertical lines on the data points represent the statistical uncertainty in the data and the hatched (filled) band corresponds to the total uncertainty in the postfit (prefit) prediction. Events that exceed the range of the plot are included in the last bin. The bin contents are divided by bin width.
• Figure 4: Number of selected -tagged jets in the event (upper left), number of selected jets in the event (upper right), of the sub-leading lepton (lower left), and $\abs{\eta}$ of the sub-leading lepton (lower right), in a CR enriched with nonprompt leptons by inverting the requirement, for data (points) and predictions (filled histograms) after the fit to the data in the SR and CR as described in Section \ref{['sec:differential']} for the loose lepton selection. The lower panels show the ratio of the data to the sum of the postfit predictions (points) and the ratio of the data to the prefit predictions (red line). The vertical lines on the data points represent the statistical uncertainty in the data and the hatched (filled) band corresponds to the total uncertainty in the postfit (prefit) prediction. Events that exceed the range of the plot are included in the last bin.
• Figure 5: of the leading lepton (left), $\abs{\eta}$ of the leading lepton (right), in a CR enriched with charge-misidentified leptons and additional jets for data (points) and predictions (filled histograms) after the fit to the data in the SR and CR as described in Section \ref{['sec:differential']} for the loose lepton selection. The lower panels show the ratio of the data to the sum of the postfit predictions (points) and the ratio of the data to the prefit predictions (red line). The vertical lines on the data points represent the statistical uncertainty in the data and the hatched (filled) band corresponds to the total uncertainty in the postfit (prefit) prediction. Events that exceed the range of the plot are included in the last bin.