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| CMS-TOP-23-004 ; CERN-EP-2024-251 | ||
| Measurements of inclusive and differential cross sections for top quark production in association with a Z boson in proton-proton collisions at $ \sqrt{s}= $ 13 TeV | ||
| CMS Collaboration | ||
| 30 October 2024 | ||
| Submitted to J. High Energy Phys. | ||
| Abstract: Measurements are presented of inclusive and differential cross sections for Z boson associated production of top quark pairs ($ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $) and single top quarks ($ \mathrm{t}\mathrm{Z}\mathrm{q} $ or $ \mathrm{t}\mathrm{W}\mathrm{Z} $). The data were recorded in proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 fb$ ^{-1} $. Events with three or more leptons, electrons or muons, are selected and a multiclass deep neural network is used to separate three event categories, the $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ processes, the $ \mathrm{t}\mathrm{Z}\mathrm{q} $ process, and the backgrounds. A profile likelihood approach is used to unfold the differential cross sections, to account for systematic uncertainties, and to determine the correlations between the two signal categories in one global fit. The inclusive cross sections for a dilepton invariant mass between 70 and 110 GeV are measured to be 1.14 $ \pm $ 0.07 pb for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $, and 0.81 $ \pm $ 0.10 pb for $ \mathrm{t}\mathrm{Z}\mathrm{q} $, in good agreement with theoretical predictions. | ||
| Links: e-print arXiv:2410.23475 [hep-ex] (PDF) ; CDS record ; inSPIRE record ; HepData record ; CADI line (restricted) ; | ||
| Figures | |
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Figure 1:
Leading order Feynman diagrams for the $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ (left), $ \mathrm{t}\mathrm{W}\mathrm{Z} $ (middle), and $ \mathrm{t}\mathrm{Z}\mathrm{q} $ (right) processes. |
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Figure 1-a:
Leading order Feynman diagrams for the $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ (left), $ \mathrm{t}\mathrm{W}\mathrm{Z} $ (middle), and $ \mathrm{t}\mathrm{Z}\mathrm{q} $ (right) processes. |
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Figure 1-b:
Leading order Feynman diagrams for the $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ (left), $ \mathrm{t}\mathrm{W}\mathrm{Z} $ (middle), and $ \mathrm{t}\mathrm{Z}\mathrm{q} $ (right) processes. |
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Figure 1-c:
Leading order Feynman diagrams for the $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ (left), $ \mathrm{t}\mathrm{W}\mathrm{Z} $ (middle), and $ \mathrm{t}\mathrm{Z}\mathrm{q} $ (right) processes. |
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Figure 2:
Distributions after final event selection: the $ p_{\mathrm{T}} $ of the lepton with the highest (upper left) and second highest (upper right) $ p_{\mathrm{T}} $, the number of jets (middle left), the number of b jets (middle right), and the $ |\eta| $ of the jet with the highest $ |\eta| $ (lower). The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 2-a:
Distributions after final event selection: the $ p_{\mathrm{T}} $ of the lepton with the highest (upper left) and second highest (upper right) $ p_{\mathrm{T}} $, the number of jets (middle left), the number of b jets (middle right), and the $ |\eta| $ of the jet with the highest $ |\eta| $ (lower). The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 2-b:
Distributions after final event selection: the $ p_{\mathrm{T}} $ of the lepton with the highest (upper left) and second highest (upper right) $ p_{\mathrm{T}} $, the number of jets (middle left), the number of b jets (middle right), and the $ |\eta| $ of the jet with the highest $ |\eta| $ (lower). The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 2-c:
Distributions after final event selection: the $ p_{\mathrm{T}} $ of the lepton with the highest (upper left) and second highest (upper right) $ p_{\mathrm{T}} $, the number of jets (middle left), the number of b jets (middle right), and the $ |\eta| $ of the jet with the highest $ |\eta| $ (lower). The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 2-d:
Distributions after final event selection: the $ p_{\mathrm{T}} $ of the lepton with the highest (upper left) and second highest (upper right) $ p_{\mathrm{T}} $, the number of jets (middle left), the number of b jets (middle right), and the $ |\eta| $ of the jet with the highest $ |\eta| $ (lower). The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 2-e:
Distributions after final event selection: the $ p_{\mathrm{T}} $ of the lepton with the highest (upper left) and second highest (upper right) $ p_{\mathrm{T}} $, the number of jets (middle left), the number of b jets (middle right), and the $ |\eta| $ of the jet with the highest $ |\eta| $ (lower). The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 3:
Distributions after final event selection: the $ p_{\mathrm{T}} $ of the reconstructed Z boson (upper left), the $ p_{\mathrm{T}} $ of the lepton arising from the W boson $ p_{\mathrm{T}}({{\ell}{\mathrm{W}}} ) $ (upper right), $ \Delta R(\mathrm{Z},{{\ell}{\mathrm{W}}} ) $ (middle left), $ \Delta\phi({{\ell}^{+}},{{\ell}^{-}} ) $ (middle right), and the cosine of the angle $ \cos\theta^\ast_{\mathrm{Z}} $ between the Z boson and its negatively charged decay lepton in the Z boson rest frame (lower). The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 3-a:
Distributions after final event selection: the $ p_{\mathrm{T}} $ of the reconstructed Z boson (upper left), the $ p_{\mathrm{T}} $ of the lepton arising from the W boson $ p_{\mathrm{T}}({{\ell}{\mathrm{W}}} ) $ (upper right), $ \Delta R(\mathrm{Z},{{\ell}{\mathrm{W}}} ) $ (middle left), $ \Delta\phi({{\ell}^{+}},{{\ell}^{-}} ) $ (middle right), and the cosine of the angle $ \cos\theta^\ast_{\mathrm{Z}} $ between the Z boson and its negatively charged decay lepton in the Z boson rest frame (lower). The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 3-b:
Distributions after final event selection: the $ p_{\mathrm{T}} $ of the reconstructed Z boson (upper left), the $ p_{\mathrm{T}} $ of the lepton arising from the W boson $ p_{\mathrm{T}}({{\ell}{\mathrm{W}}} ) $ (upper right), $ \Delta R(\mathrm{Z},{{\ell}{\mathrm{W}}} ) $ (middle left), $ \Delta\phi({{\ell}^{+}},{{\ell}^{-}} ) $ (middle right), and the cosine of the angle $ \cos\theta^\ast_{\mathrm{Z}} $ between the Z boson and its negatively charged decay lepton in the Z boson rest frame (lower). The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 3-c:
Distributions after final event selection: the $ p_{\mathrm{T}} $ of the reconstructed Z boson (upper left), the $ p_{\mathrm{T}} $ of the lepton arising from the W boson $ p_{\mathrm{T}}({{\ell}{\mathrm{W}}} ) $ (upper right), $ \Delta R(\mathrm{Z},{{\ell}{\mathrm{W}}} ) $ (middle left), $ \Delta\phi({{\ell}^{+}},{{\ell}^{-}} ) $ (middle right), and the cosine of the angle $ \cos\theta^\ast_{\mathrm{Z}} $ between the Z boson and its negatively charged decay lepton in the Z boson rest frame (lower). The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 3-d:
Distributions after final event selection: the $ p_{\mathrm{T}} $ of the reconstructed Z boson (upper left), the $ p_{\mathrm{T}} $ of the lepton arising from the W boson $ p_{\mathrm{T}}({{\ell}{\mathrm{W}}} ) $ (upper right), $ \Delta R(\mathrm{Z},{{\ell}{\mathrm{W}}} ) $ (middle left), $ \Delta\phi({{\ell}^{+}},{{\ell}^{-}} ) $ (middle right), and the cosine of the angle $ \cos\theta^\ast_{\mathrm{Z}} $ between the Z boson and its negatively charged decay lepton in the Z boson rest frame (lower). The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 3-e:
Distributions after final event selection: the $ p_{\mathrm{T}} $ of the reconstructed Z boson (upper left), the $ p_{\mathrm{T}} $ of the lepton arising from the W boson $ p_{\mathrm{T}}({{\ell}{\mathrm{W}}} ) $ (upper right), $ \Delta R(\mathrm{Z},{{\ell}{\mathrm{W}}} ) $ (middle left), $ \Delta\phi({{\ell}^{+}},{{\ell}^{-}} ) $ (middle right), and the cosine of the angle $ \cos\theta^\ast_{\mathrm{Z}} $ between the Z boson and its negatively charged decay lepton in the Z boson rest frame (lower). The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 4:
Distributions for events selected in the region with $ |m({{\ell}^{+}} {{\ell}^{-}} )-m(\mathrm{Z})| > $ 20 GeV for: the $ p_{\mathrm{T}} $ of the lepton with the highest (upper left) and second highest (upper right) $ p_{\mathrm{T}} $, the number of jets (lower left), and the number of b jets (lower right). The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 4-a:
Distributions for events selected in the region with $ |m({{\ell}^{+}} {{\ell}^{-}} )-m(\mathrm{Z})| > $ 20 GeV for: the $ p_{\mathrm{T}} $ of the lepton with the highest (upper left) and second highest (upper right) $ p_{\mathrm{T}} $, the number of jets (lower left), and the number of b jets (lower right). The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 4-b:
Distributions for events selected in the region with $ |m({{\ell}^{+}} {{\ell}^{-}} )-m(\mathrm{Z})| > $ 20 GeV for: the $ p_{\mathrm{T}} $ of the lepton with the highest (upper left) and second highest (upper right) $ p_{\mathrm{T}} $, the number of jets (lower left), and the number of b jets (lower right). The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 4-c:
Distributions for events selected in the region with $ |m({{\ell}^{+}} {{\ell}^{-}} )-m(\mathrm{Z})| > $ 20 GeV for: the $ p_{\mathrm{T}} $ of the lepton with the highest (upper left) and second highest (upper right) $ p_{\mathrm{T}} $, the number of jets (lower left), and the number of b jets (lower right). The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 4-d:
Distributions for events selected in the region with $ |m({{\ell}^{+}} {{\ell}^{-}} )-m(\mathrm{Z})| > $ 20 GeV for: the $ p_{\mathrm{T}} $ of the lepton with the highest (upper left) and second highest (upper right) $ p_{\mathrm{T}} $, the number of jets (lower left), and the number of b jets (lower right). The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 5:
Distributions of the output values in the three DNN output nodes for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ (upper), $ \mathrm{t}\mathrm{Z}\mathrm{q} $ (middle), and background (lower). The data are compared with expectations. In the left column, the inclusive distributions are shown, i.e.,, each selected event enters each of the output nodes. In the right column, each event enters exactly one of the three distributions, namely the one for which the output score is largest. The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 5-a:
Distributions of the output values in the three DNN output nodes for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ (upper), $ \mathrm{t}\mathrm{Z}\mathrm{q} $ (middle), and background (lower). The data are compared with expectations. In the left column, the inclusive distributions are shown, i.e.,, each selected event enters each of the output nodes. In the right column, each event enters exactly one of the three distributions, namely the one for which the output score is largest. The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 5-b:
Distributions of the output values in the three DNN output nodes for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ (upper), $ \mathrm{t}\mathrm{Z}\mathrm{q} $ (middle), and background (lower). The data are compared with expectations. In the left column, the inclusive distributions are shown, i.e.,, each selected event enters each of the output nodes. In the right column, each event enters exactly one of the three distributions, namely the one for which the output score is largest. The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 5-c:
Distributions of the output values in the three DNN output nodes for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ (upper), $ \mathrm{t}\mathrm{Z}\mathrm{q} $ (middle), and background (lower). The data are compared with expectations. In the left column, the inclusive distributions are shown, i.e.,, each selected event enters each of the output nodes. In the right column, each event enters exactly one of the three distributions, namely the one for which the output score is largest. The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 5-d:
Distributions of the output values in the three DNN output nodes for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ (upper), $ \mathrm{t}\mathrm{Z}\mathrm{q} $ (middle), and background (lower). The data are compared with expectations. In the left column, the inclusive distributions are shown, i.e.,, each selected event enters each of the output nodes. In the right column, each event enters exactly one of the three distributions, namely the one for which the output score is largest. The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 5-e:
Distributions of the output values in the three DNN output nodes for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ (upper), $ \mathrm{t}\mathrm{Z}\mathrm{q} $ (middle), and background (lower). The data are compared with expectations. In the left column, the inclusive distributions are shown, i.e.,, each selected event enters each of the output nodes. In the right column, each event enters exactly one of the three distributions, namely the one for which the output score is largest. The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 5-f:
Distributions of the output values in the three DNN output nodes for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ (upper), $ \mathrm{t}\mathrm{Z}\mathrm{q} $ (middle), and background (lower). The data are compared with expectations. In the left column, the inclusive distributions are shown, i.e.,, each selected event enters each of the output nodes. In the right column, each event enters exactly one of the three distributions, namely the one for which the output score is largest. The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 6:
Distributions of the b jet multiplicity in the four lepton region (left) and the jet multiplicity in the zero b jet control region (right). The data are compared to the expectation. The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 6-a:
Distributions of the b jet multiplicity in the four lepton region (left) and the jet multiplicity in the zero b jet control region (right). The data are compared to the expectation. The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 6-b:
Distributions of the b jet multiplicity in the four lepton region (left) and the jet multiplicity in the zero b jet control region (right). The data are compared to the expectation. The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 7:
Postfit distributions of the b jet multiplicity in events with four leptons (upper left) and the jet multiplicity distribution in events with zero b jets (upper right). Postfit distributions in the output nodes for $ \mathrm{t}\mathrm{Z}\mathrm{q} $ (middle left), $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z}\text{+}\mathrm{t}\mathrm{W}\mathrm{Z} $ (middle right), and the background (lower). The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 7-a:
Postfit distributions of the b jet multiplicity in events with four leptons (upper left) and the jet multiplicity distribution in events with zero b jets (upper right). Postfit distributions in the output nodes for $ \mathrm{t}\mathrm{Z}\mathrm{q} $ (middle left), $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z}\text{+}\mathrm{t}\mathrm{W}\mathrm{Z} $ (middle right), and the background (lower). The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 7-b:
Postfit distributions of the b jet multiplicity in events with four leptons (upper left) and the jet multiplicity distribution in events with zero b jets (upper right). Postfit distributions in the output nodes for $ \mathrm{t}\mathrm{Z}\mathrm{q} $ (middle left), $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z}\text{+}\mathrm{t}\mathrm{W}\mathrm{Z} $ (middle right), and the background (lower). The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 7-c:
Postfit distributions of the b jet multiplicity in events with four leptons (upper left) and the jet multiplicity distribution in events with zero b jets (upper right). Postfit distributions in the output nodes for $ \mathrm{t}\mathrm{Z}\mathrm{q} $ (middle left), $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z}\text{+}\mathrm{t}\mathrm{W}\mathrm{Z} $ (middle right), and the background (lower). The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 7-d:
Postfit distributions of the b jet multiplicity in events with four leptons (upper left) and the jet multiplicity distribution in events with zero b jets (upper right). Postfit distributions in the output nodes for $ \mathrm{t}\mathrm{Z}\mathrm{q} $ (middle left), $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z}\text{+}\mathrm{t}\mathrm{W}\mathrm{Z} $ (middle right), and the background (lower). The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 7-e:
Postfit distributions of the b jet multiplicity in events with four leptons (upper left) and the jet multiplicity distribution in events with zero b jets (upper right). Postfit distributions in the output nodes for $ \mathrm{t}\mathrm{Z}\mathrm{q} $ (middle left), $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z}\text{+}\mathrm{t}\mathrm{W}\mathrm{Z} $ (middle right), and the background (lower). The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 8:
Profile likelihood ratio of the two measured inclusive cross sections normalized to the SM predictions $ \mu_{{\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z}\text{+}\mathrm{t}\mathrm{W}\mathrm{Z}} $ and $ \mu_{\mathrm{t}\mathrm{Z}\mathrm{q}} $. The color axis shows twice the negative log-likelihood difference. The measurement is indicated by a cross, and the SM prediction by a diamond. The 68% and 95% confidence levels (CL) ($ -2\Delta\ln{L}= $ 2.30 and 5.99, respectively) are indicated by the red lines. |
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Figure 9:
Prefit (upper) and postfit (lower) output node distributions for the sum of the $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ processes. Separate templates are shown for each bin of reconstructed $ p_{\mathrm{T}}(\mathrm{Z}) $. The signal samples are further split into four components each, shown by different colors, according to the generator-level bins of $ p_{\mathrm{T}}(\mathrm{Z}) $. The fit is performed simultaneously on this distribution and that in Fig. 10. The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 9-a:
Prefit (upper) and postfit (lower) output node distributions for the sum of the $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ processes. Separate templates are shown for each bin of reconstructed $ p_{\mathrm{T}}(\mathrm{Z}) $. The signal samples are further split into four components each, shown by different colors, according to the generator-level bins of $ p_{\mathrm{T}}(\mathrm{Z}) $. The fit is performed simultaneously on this distribution and that in Fig. 10. The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 9-b:
Prefit (upper) and postfit (lower) output node distributions for the sum of the $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ processes. Separate templates are shown for each bin of reconstructed $ p_{\mathrm{T}}(\mathrm{Z}) $. The signal samples are further split into four components each, shown by different colors, according to the generator-level bins of $ p_{\mathrm{T}}(\mathrm{Z}) $. The fit is performed simultaneously on this distribution and that in Fig. 10. The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 10:
Prefit (upper) and postfit (lower) output node distributions for the $ \mathrm{t}\mathrm{Z}\mathrm{q} $ process. Separate templates are shown for each bin of reconstructed $ p_{\mathrm{T}}(\mathrm{Z}) $. The signal samples are further split into four components each, shown by different colors, according to the generator-level bins of $ p_{\mathrm{T}}(\mathrm{Z}) $. The fit is performed simultaneously on this distribution and that in Fig. 9. The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
png pdf |
Figure 10-a:
Prefit (upper) and postfit (lower) output node distributions for the $ \mathrm{t}\mathrm{Z}\mathrm{q} $ process. Separate templates are shown for each bin of reconstructed $ p_{\mathrm{T}}(\mathrm{Z}) $. The signal samples are further split into four components each, shown by different colors, according to the generator-level bins of $ p_{\mathrm{T}}(\mathrm{Z}) $. The fit is performed simultaneously on this distribution and that in Fig. 9. The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
png pdf |
Figure 10-b:
Prefit (upper) and postfit (lower) output node distributions for the $ \mathrm{t}\mathrm{Z}\mathrm{q} $ process. Separate templates are shown for each bin of reconstructed $ p_{\mathrm{T}}(\mathrm{Z}) $. The signal samples are further split into four components each, shown by different colors, according to the generator-level bins of $ p_{\mathrm{T}}(\mathrm{Z}) $. The fit is performed simultaneously on this distribution and that in Fig. 9. The data are displayed as points with statistical error bars and the expectation is shown with a histogram with the systematic uncertainty given by the hatched area. |
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Figure 11:
Differential cross sections for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ production (left column) and $ \mathrm{t}\mathrm{Z}\mathrm{q} $ production (right column) as a function of $ p_{\mathrm{T}}(\mathrm{Z}) $ (upper), $ p_{\mathrm{T}}({{\ell}{\mathrm{W}}} ) $ (middle), and $ \Delta\phi({{\ell}^{+}},{{\ell}^{-}} ) $ (lower). The inner (outer) error bars indicate the statistical (total) uncertainty, while the shaded area refers to the uncertainty in the theory prediction. The lower panel shows the ratio of the prediction with the data. The points at unity show the uncertainty of the data. |
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Figure 11-a:
Differential cross sections for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ production (left column) and $ \mathrm{t}\mathrm{Z}\mathrm{q} $ production (right column) as a function of $ p_{\mathrm{T}}(\mathrm{Z}) $ (upper), $ p_{\mathrm{T}}({{\ell}{\mathrm{W}}} ) $ (middle), and $ \Delta\phi({{\ell}^{+}},{{\ell}^{-}} ) $ (lower). The inner (outer) error bars indicate the statistical (total) uncertainty, while the shaded area refers to the uncertainty in the theory prediction. The lower panel shows the ratio of the prediction with the data. The points at unity show the uncertainty of the data. |
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Figure 11-b:
Differential cross sections for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ production (left column) and $ \mathrm{t}\mathrm{Z}\mathrm{q} $ production (right column) as a function of $ p_{\mathrm{T}}(\mathrm{Z}) $ (upper), $ p_{\mathrm{T}}({{\ell}{\mathrm{W}}} ) $ (middle), and $ \Delta\phi({{\ell}^{+}},{{\ell}^{-}} ) $ (lower). The inner (outer) error bars indicate the statistical (total) uncertainty, while the shaded area refers to the uncertainty in the theory prediction. The lower panel shows the ratio of the prediction with the data. The points at unity show the uncertainty of the data. |
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Figure 11-c:
Differential cross sections for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ production (left column) and $ \mathrm{t}\mathrm{Z}\mathrm{q} $ production (right column) as a function of $ p_{\mathrm{T}}(\mathrm{Z}) $ (upper), $ p_{\mathrm{T}}({{\ell}{\mathrm{W}}} ) $ (middle), and $ \Delta\phi({{\ell}^{+}},{{\ell}^{-}} ) $ (lower). The inner (outer) error bars indicate the statistical (total) uncertainty, while the shaded area refers to the uncertainty in the theory prediction. The lower panel shows the ratio of the prediction with the data. The points at unity show the uncertainty of the data. |
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Figure 11-d:
Differential cross sections for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ production (left column) and $ \mathrm{t}\mathrm{Z}\mathrm{q} $ production (right column) as a function of $ p_{\mathrm{T}}(\mathrm{Z}) $ (upper), $ p_{\mathrm{T}}({{\ell}{\mathrm{W}}} ) $ (middle), and $ \Delta\phi({{\ell}^{+}},{{\ell}^{-}} ) $ (lower). The inner (outer) error bars indicate the statistical (total) uncertainty, while the shaded area refers to the uncertainty in the theory prediction. The lower panel shows the ratio of the prediction with the data. The points at unity show the uncertainty of the data. |
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Figure 11-e:
Differential cross sections for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ production (left column) and $ \mathrm{t}\mathrm{Z}\mathrm{q} $ production (right column) as a function of $ p_{\mathrm{T}}(\mathrm{Z}) $ (upper), $ p_{\mathrm{T}}({{\ell}{\mathrm{W}}} ) $ (middle), and $ \Delta\phi({{\ell}^{+}},{{\ell}^{-}} ) $ (lower). The inner (outer) error bars indicate the statistical (total) uncertainty, while the shaded area refers to the uncertainty in the theory prediction. The lower panel shows the ratio of the prediction with the data. The points at unity show the uncertainty of the data. |
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Figure 11-f:
Differential cross sections for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ production (left column) and $ \mathrm{t}\mathrm{Z}\mathrm{q} $ production (right column) as a function of $ p_{\mathrm{T}}(\mathrm{Z}) $ (upper), $ p_{\mathrm{T}}({{\ell}{\mathrm{W}}} ) $ (middle), and $ \Delta\phi({{\ell}^{+}},{{\ell}^{-}} ) $ (lower). The inner (outer) error bars indicate the statistical (total) uncertainty, while the shaded area refers to the uncertainty in the theory prediction. The lower panel shows the ratio of the prediction with the data. The points at unity show the uncertainty of the data. |
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Figure 12:
Differential cross sections for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ production (left column) and $ \mathrm{t}\mathrm{Z}\mathrm{q} $ production (right column) as a function of $ \Delta R(\mathrm{Z},{{\ell}{\mathrm{W}}} ) $ (upper), and $ \cos\theta^\ast_{\mathrm{Z}} $ (lower). The inner (outer) error bars indicate the statistical (total) uncertainty, while the shaded area refers to the uncertainty in the theory prediction. The lower panel shows the ratio of the prediction with the data. The points at unity show the uncertainty of the data. |
png pdf |
Figure 12-a:
Differential cross sections for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ production (left column) and $ \mathrm{t}\mathrm{Z}\mathrm{q} $ production (right column) as a function of $ \Delta R(\mathrm{Z},{{\ell}{\mathrm{W}}} ) $ (upper), and $ \cos\theta^\ast_{\mathrm{Z}} $ (lower). The inner (outer) error bars indicate the statistical (total) uncertainty, while the shaded area refers to the uncertainty in the theory prediction. The lower panel shows the ratio of the prediction with the data. The points at unity show the uncertainty of the data. |
png pdf |
Figure 12-b:
Differential cross sections for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ production (left column) and $ \mathrm{t}\mathrm{Z}\mathrm{q} $ production (right column) as a function of $ \Delta R(\mathrm{Z},{{\ell}{\mathrm{W}}} ) $ (upper), and $ \cos\theta^\ast_{\mathrm{Z}} $ (lower). The inner (outer) error bars indicate the statistical (total) uncertainty, while the shaded area refers to the uncertainty in the theory prediction. The lower panel shows the ratio of the prediction with the data. The points at unity show the uncertainty of the data. |
png pdf |
Figure 12-c:
Differential cross sections for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ production (left column) and $ \mathrm{t}\mathrm{Z}\mathrm{q} $ production (right column) as a function of $ \Delta R(\mathrm{Z},{{\ell}{\mathrm{W}}} ) $ (upper), and $ \cos\theta^\ast_{\mathrm{Z}} $ (lower). The inner (outer) error bars indicate the statistical (total) uncertainty, while the shaded area refers to the uncertainty in the theory prediction. The lower panel shows the ratio of the prediction with the data. The points at unity show the uncertainty of the data. |
png pdf |
Figure 12-d:
Differential cross sections for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ production (left column) and $ \mathrm{t}\mathrm{Z}\mathrm{q} $ production (right column) as a function of $ \Delta R(\mathrm{Z},{{\ell}{\mathrm{W}}} ) $ (upper), and $ \cos\theta^\ast_{\mathrm{Z}} $ (lower). The inner (outer) error bars indicate the statistical (total) uncertainty, while the shaded area refers to the uncertainty in the theory prediction. The lower panel shows the ratio of the prediction with the data. The points at unity show the uncertainty of the data. |
png pdf |
Figure 13:
Normalized differential cross sections for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ production (left column) and $ \mathrm{t}\mathrm{Z}\mathrm{q} $ production (right column) as a function of $ p_{\mathrm{T}}(\mathrm{Z}) $ (upper), $ p_{\mathrm{T}}({{\ell}{\mathrm{W}}} ) $ (middle), and $ \Delta\phi({{\ell}^{+}},{{\ell}^{-}} ) $ (lower). The inner (outer) error bars indicate the statistical (total) uncertainty, while the shaded area refers to the uncertainty in the theory prediction. The lower panel shows the ratio of the prediction with the data. The points at unity show the uncertainty of the data. |
png pdf |
Figure 13-a:
Normalized differential cross sections for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ production (left column) and $ \mathrm{t}\mathrm{Z}\mathrm{q} $ production (right column) as a function of $ p_{\mathrm{T}}(\mathrm{Z}) $ (upper), $ p_{\mathrm{T}}({{\ell}{\mathrm{W}}} ) $ (middle), and $ \Delta\phi({{\ell}^{+}},{{\ell}^{-}} ) $ (lower). The inner (outer) error bars indicate the statistical (total) uncertainty, while the shaded area refers to the uncertainty in the theory prediction. The lower panel shows the ratio of the prediction with the data. The points at unity show the uncertainty of the data. |
png pdf |
Figure 13-b:
Normalized differential cross sections for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ production (left column) and $ \mathrm{t}\mathrm{Z}\mathrm{q} $ production (right column) as a function of $ p_{\mathrm{T}}(\mathrm{Z}) $ (upper), $ p_{\mathrm{T}}({{\ell}{\mathrm{W}}} ) $ (middle), and $ \Delta\phi({{\ell}^{+}},{{\ell}^{-}} ) $ (lower). The inner (outer) error bars indicate the statistical (total) uncertainty, while the shaded area refers to the uncertainty in the theory prediction. The lower panel shows the ratio of the prediction with the data. The points at unity show the uncertainty of the data. |
png pdf |
Figure 13-c:
Normalized differential cross sections for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ production (left column) and $ \mathrm{t}\mathrm{Z}\mathrm{q} $ production (right column) as a function of $ p_{\mathrm{T}}(\mathrm{Z}) $ (upper), $ p_{\mathrm{T}}({{\ell}{\mathrm{W}}} ) $ (middle), and $ \Delta\phi({{\ell}^{+}},{{\ell}^{-}} ) $ (lower). The inner (outer) error bars indicate the statistical (total) uncertainty, while the shaded area refers to the uncertainty in the theory prediction. The lower panel shows the ratio of the prediction with the data. The points at unity show the uncertainty of the data. |
png pdf |
Figure 13-d:
Normalized differential cross sections for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ production (left column) and $ \mathrm{t}\mathrm{Z}\mathrm{q} $ production (right column) as a function of $ p_{\mathrm{T}}(\mathrm{Z}) $ (upper), $ p_{\mathrm{T}}({{\ell}{\mathrm{W}}} ) $ (middle), and $ \Delta\phi({{\ell}^{+}},{{\ell}^{-}} ) $ (lower). The inner (outer) error bars indicate the statistical (total) uncertainty, while the shaded area refers to the uncertainty in the theory prediction. The lower panel shows the ratio of the prediction with the data. The points at unity show the uncertainty of the data. |
png pdf |
Figure 13-e:
Normalized differential cross sections for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ production (left column) and $ \mathrm{t}\mathrm{Z}\mathrm{q} $ production (right column) as a function of $ p_{\mathrm{T}}(\mathrm{Z}) $ (upper), $ p_{\mathrm{T}}({{\ell}{\mathrm{W}}} ) $ (middle), and $ \Delta\phi({{\ell}^{+}},{{\ell}^{-}} ) $ (lower). The inner (outer) error bars indicate the statistical (total) uncertainty, while the shaded area refers to the uncertainty in the theory prediction. The lower panel shows the ratio of the prediction with the data. The points at unity show the uncertainty of the data. |
png pdf |
Figure 13-f:
Normalized differential cross sections for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ production (left column) and $ \mathrm{t}\mathrm{Z}\mathrm{q} $ production (right column) as a function of $ p_{\mathrm{T}}(\mathrm{Z}) $ (upper), $ p_{\mathrm{T}}({{\ell}{\mathrm{W}}} ) $ (middle), and $ \Delta\phi({{\ell}^{+}},{{\ell}^{-}} ) $ (lower). The inner (outer) error bars indicate the statistical (total) uncertainty, while the shaded area refers to the uncertainty in the theory prediction. The lower panel shows the ratio of the prediction with the data. The points at unity show the uncertainty of the data. |
png pdf |
Figure 14:
Normalized differential cross sections for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ production (left column) and $ \mathrm{t}\mathrm{Z}\mathrm{q} $ production (right column) as a function of $ \Delta R(\mathrm{Z},{{\ell}{\mathrm{W}}} ) $ (upper), and $ \cos\theta^\ast_{\mathrm{Z}} $ (lower). The inner (outer) error bars indicate the statistical (total) uncertainty, while the shaded area refers to the uncertainty in the theory prediction. The lower panel shows the ratio of the prediction with the data. The points at unity show the uncertainty of the data. |
png pdf |
Figure 14-a:
Normalized differential cross sections for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ production (left column) and $ \mathrm{t}\mathrm{Z}\mathrm{q} $ production (right column) as a function of $ \Delta R(\mathrm{Z},{{\ell}{\mathrm{W}}} ) $ (upper), and $ \cos\theta^\ast_{\mathrm{Z}} $ (lower). The inner (outer) error bars indicate the statistical (total) uncertainty, while the shaded area refers to the uncertainty in the theory prediction. The lower panel shows the ratio of the prediction with the data. The points at unity show the uncertainty of the data. |
png pdf |
Figure 14-b:
Normalized differential cross sections for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ production (left column) and $ \mathrm{t}\mathrm{Z}\mathrm{q} $ production (right column) as a function of $ \Delta R(\mathrm{Z},{{\ell}{\mathrm{W}}} ) $ (upper), and $ \cos\theta^\ast_{\mathrm{Z}} $ (lower). The inner (outer) error bars indicate the statistical (total) uncertainty, while the shaded area refers to the uncertainty in the theory prediction. The lower panel shows the ratio of the prediction with the data. The points at unity show the uncertainty of the data. |
png pdf |
Figure 14-c:
Normalized differential cross sections for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ production (left column) and $ \mathrm{t}\mathrm{Z}\mathrm{q} $ production (right column) as a function of $ \Delta R(\mathrm{Z},{{\ell}{\mathrm{W}}} ) $ (upper), and $ \cos\theta^\ast_{\mathrm{Z}} $ (lower). The inner (outer) error bars indicate the statistical (total) uncertainty, while the shaded area refers to the uncertainty in the theory prediction. The lower panel shows the ratio of the prediction with the data. The points at unity show the uncertainty of the data. |
png pdf |
Figure 14-d:
Normalized differential cross sections for the sum of $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ production (left column) and $ \mathrm{t}\mathrm{Z}\mathrm{q} $ production (right column) as a function of $ \Delta R(\mathrm{Z},{{\ell}{\mathrm{W}}} ) $ (upper), and $ \cos\theta^\ast_{\mathrm{Z}} $ (lower). The inner (outer) error bars indicate the statistical (total) uncertainty, while the shaded area refers to the uncertainty in the theory prediction. The lower panel shows the ratio of the prediction with the data. The points at unity show the uncertainty of the data. |
png pdf |
Figure 15:
Covariance matrices for the simultaneous measurement of the differential cross section as a function of $ p_{\mathrm{T}}(\mathrm{Z}) $, (upper left), $ p_{\mathrm{T}}({{\ell}{\mathrm{W}}} ) $ (upper right), $ \Delta R(\mathrm{Z},{{\ell}{\mathrm{W}}} ) $ (middle left), $ \Delta\phi({{\ell}^{+}},{{\ell}^{-}} ) $ (middle right), and $ \cos\theta^\ast_{\mathrm{Z}} $ (lower). The last digits in the axis labels refer to the respective bin of the corresponding differential cross section measurement. |
png pdf |
Figure 15-a:
Covariance matrices for the simultaneous measurement of the differential cross section as a function of $ p_{\mathrm{T}}(\mathrm{Z}) $, (upper left), $ p_{\mathrm{T}}({{\ell}{\mathrm{W}}} ) $ (upper right), $ \Delta R(\mathrm{Z},{{\ell}{\mathrm{W}}} ) $ (middle left), $ \Delta\phi({{\ell}^{+}},{{\ell}^{-}} ) $ (middle right), and $ \cos\theta^\ast_{\mathrm{Z}} $ (lower). The last digits in the axis labels refer to the respective bin of the corresponding differential cross section measurement. |
png pdf |
Figure 15-b:
Covariance matrices for the simultaneous measurement of the differential cross section as a function of $ p_{\mathrm{T}}(\mathrm{Z}) $, (upper left), $ p_{\mathrm{T}}({{\ell}{\mathrm{W}}} ) $ (upper right), $ \Delta R(\mathrm{Z},{{\ell}{\mathrm{W}}} ) $ (middle left), $ \Delta\phi({{\ell}^{+}},{{\ell}^{-}} ) $ (middle right), and $ \cos\theta^\ast_{\mathrm{Z}} $ (lower). The last digits in the axis labels refer to the respective bin of the corresponding differential cross section measurement. |
png pdf |
Figure 15-c:
Covariance matrices for the simultaneous measurement of the differential cross section as a function of $ p_{\mathrm{T}}(\mathrm{Z}) $, (upper left), $ p_{\mathrm{T}}({{\ell}{\mathrm{W}}} ) $ (upper right), $ \Delta R(\mathrm{Z},{{\ell}{\mathrm{W}}} ) $ (middle left), $ \Delta\phi({{\ell}^{+}},{{\ell}^{-}} ) $ (middle right), and $ \cos\theta^\ast_{\mathrm{Z}} $ (lower). The last digits in the axis labels refer to the respective bin of the corresponding differential cross section measurement. |
png pdf |
Figure 15-d:
Covariance matrices for the simultaneous measurement of the differential cross section as a function of $ p_{\mathrm{T}}(\mathrm{Z}) $, (upper left), $ p_{\mathrm{T}}({{\ell}{\mathrm{W}}} ) $ (upper right), $ \Delta R(\mathrm{Z},{{\ell}{\mathrm{W}}} ) $ (middle left), $ \Delta\phi({{\ell}^{+}},{{\ell}^{-}} ) $ (middle right), and $ \cos\theta^\ast_{\mathrm{Z}} $ (lower). The last digits in the axis labels refer to the respective bin of the corresponding differential cross section measurement. |
png pdf |
Figure 15-e:
Covariance matrices for the simultaneous measurement of the differential cross section as a function of $ p_{\mathrm{T}}(\mathrm{Z}) $, (upper left), $ p_{\mathrm{T}}({{\ell}{\mathrm{W}}} ) $ (upper right), $ \Delta R(\mathrm{Z},{{\ell}{\mathrm{W}}} ) $ (middle left), $ \Delta\phi({{\ell}^{+}},{{\ell}^{-}} ) $ (middle right), and $ \cos\theta^\ast_{\mathrm{Z}} $ (lower). The last digits in the axis labels refer to the respective bin of the corresponding differential cross section measurement. |
| Tables | |
png pdf |
Table 1:
Systematic uncertainty sources and their relative impact on the inclusive $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z}\text{+}\mathrm{t}\mathrm{W}\mathrm{Z} $ and $ \mathrm{t}\mathrm{Z}\mathrm{q} $ cross section measurements. |
| Summary |
| A first simultaneous measurement of single and pair production of top quarks in association with a Z boson is presented. The data were recorded by the CMS experiment in proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 fb$ ^{-1} $. Events with three or more leptons (electrons or muons) are analysed. The separation between the signals is achieved using a deep neural network classifier with three output nodes for the combined $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ and $ \mathrm{t}\mathrm{W}\mathrm{Z} $ processes, the $ \mathrm{t}\mathrm{Z}\mathrm{q} $ process, and the backgrounds. The inclusive cross sections are measured to be $ \sigma({\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z}\text{+}\mathrm{t}\mathrm{W}\mathrm{Z})= $ 1.14 $ \pm $ 0.07 pb for the sum of the $ \mathrm{t}\mathrm{W}\mathrm{Z} $ and $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z} $ processes, and $ \sigma(\mathrm{t}\mathrm{Z}\mathrm{q})= $ 0.81 $ \pm $ 0.10 pb for $ \mathrm{t}\mathrm{Z}\mathrm{q} $ production. Both results are evaluated for a dilepton invariant mass between 70 and 110 GeV. The cross sections are measured differentially as functions of several observables. Good agreement with theoretical predictions is found for the $ \mathrm{t}\mathrm{Z}\mathrm{q} $ process, while for $ {\mathrm{t}\overline{\mathrm{t}}} \mathrm{Z}\text{+}\mathrm{t}\mathrm{W}\mathrm{Z} $ production, the slope in the transverse momentum distribution of the lepton that originates from the W boson is found to be somewhat steeper than predicted. |
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Compact Muon Solenoid LHC, CERN |
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