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| CMS-PAS-TOP-20-010 | ||
| Inclusive and differential cross section measurements of single top quark production in association with a Z boson in proton-proton collisions at $\sqrt{s} = $ 13 TeV | ||
| CMS Collaboration | ||
| June 2021 | ||
| Abstract: Inclusive and differential cross sections of single top quark production in association with a Z boson are measured in proton-proton collisions at a center-of-mass energy of 13 TeV with an integrated luminosity of 138 fb$^{-1}$ recorded by the CMS experiment. Events are selected based on the presence of three leptons, electrons or muons, associated with leptonic Z boson and top quark decays. The measurement yields an inclusive cross section of 87.9 ${}_{-7.3}^{+7.5}$ (stat) ${}_{-6.0}^{+7.3}$ (syst) fb for a dilepton invariant mass greater than 30 GeV, in agreement with standard model (SM) calculations. The ratio between the cross sections for the top quark and the top antiquark production in association with a Z boson is measured as 2.37 ${}_{-0.42}^{+0.56}$ (stat) ${}_{-0.13}^{+0.27}$ (syst). Differential measurements at parton and particle levels are performed for the first time. Several kinematic observables are considered to study the modeling of the process. Results are compared to theoretical predictions with different assumptions on the source of the initial-state b quark and found to be in agreement, within the uncertainties. Additionally, the spin asymmetry, which is sensitive to the top quark polarization, is determined from the differential distribution of the polarization angle at parton level to be 0.58 ${}^{+0.15}_{-0.16}$ (stat) $\pm$ 0.06 (syst), in agreement with SM predictions using the MADGRAPH_aMC@NLO event generator at next-to-leading order. | ||
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These preliminary results are superseded in this paper, Submitted to JHEP. The superseded preliminary plots can be found here. |
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| Figures | |
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Figure 1:
Representative leading-order Feynman diagrams for the tZq production process. The production mechanism of nonresonant dilepton pairs (lower right) is included in the signal definition to correctly account for interference effects. |
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Figure 1-a:
Representative leading-order Feynman diagrams for the tZq production process. The production mechanism of nonresonant dilepton pairs (lower right) is included in the signal definition to correctly account for interference effects. |
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Figure 1-b:
Representative leading-order Feynman diagrams for the tZq production process. The production mechanism of nonresonant dilepton pairs (lower right) is included in the signal definition to correctly account for interference effects. |
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Figure 1-c:
Representative leading-order Feynman diagrams for the tZq production process. The production mechanism of nonresonant dilepton pairs (lower right) is included in the signal definition to correctly account for interference effects. |
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Figure 1-d:
Representative leading-order Feynman diagrams for the tZq production process. The production mechanism of nonresonant dilepton pairs (lower right) is included in the signal definition to correctly account for interference effects. |
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Figure 1-e:
Representative leading-order Feynman diagrams for the tZq production process. The production mechanism of nonresonant dilepton pairs (lower right) is included in the signal definition to correctly account for interference effects. |
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Figure 1-f:
Representative leading-order Feynman diagrams for the tZq production process. The production mechanism of nonresonant dilepton pairs (lower right) is included in the signal definition to correctly account for interference effects. |
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Figure 2:
An example of the LO (left) and NLO (right) Feynman diagrams for the tZq production process in the 4FS, in the final state with three leptons. The Z/$\gamma ^{*}$ interference term is included in the MC event simulation. In the case of the NLO generation, the gg- and ${\mathrm{q} \mathrm{\bar{q}}} $-initiated processes are possible, with an additional quark or gluon present in the final state. |
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Figure 2-a:
An example of the LO (left) and NLO (right) Feynman diagrams for the tZq production process in the 4FS, in the final state with three leptons. The Z/$\gamma ^{*}$ interference term is included in the MC event simulation. In the case of the NLO generation, the gg- and ${\mathrm{q} \mathrm{\bar{q}}} $-initiated processes are possible, with an additional quark or gluon present in the final state. |
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Figure 2-b:
An example of the LO (left) and NLO (right) Feynman diagrams for the tZq production process in the 4FS, in the final state with three leptons. The Z/$\gamma ^{*}$ interference term is included in the MC event simulation. In the case of the NLO generation, the gg- and ${\mathrm{q} \mathrm{\bar{q}}} $-initiated processes are possible, with an additional quark or gluon present in the final state. |
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Figure 3:
Distributions of the most powerful discriminating variables in the signal region: The scalar ${p_{\mathrm {T}}}$ sum of all jets (upper left), the maximum invariant mass of any two-jet system (upper right), the maximum DeepJet score of any jet (middle left), the maximum ${p_{\mathrm {T}}}$ value of any two-jet system (middle right), the number of jets in the event (lower left), and the $ {{| \eta |}} $ of the recoiling jet (lower right). The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 3-a:
Distributions of the most powerful discriminating variables in the signal region: The scalar ${p_{\mathrm {T}}}$ sum of all jets (upper left), the maximum invariant mass of any two-jet system (upper right), the maximum DeepJet score of any jet (middle left), the maximum ${p_{\mathrm {T}}}$ value of any two-jet system (middle right), the number of jets in the event (lower left), and the $ {{| \eta |}} $ of the recoiling jet (lower right). The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 3-b:
Distributions of the most powerful discriminating variables in the signal region: The scalar ${p_{\mathrm {T}}}$ sum of all jets (upper left), the maximum invariant mass of any two-jet system (upper right), the maximum DeepJet score of any jet (middle left), the maximum ${p_{\mathrm {T}}}$ value of any two-jet system (middle right), the number of jets in the event (lower left), and the $ {{| \eta |}} $ of the recoiling jet (lower right). The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 3-c:
Distributions of the most powerful discriminating variables in the signal region: The scalar ${p_{\mathrm {T}}}$ sum of all jets (upper left), the maximum invariant mass of any two-jet system (upper right), the maximum DeepJet score of any jet (middle left), the maximum ${p_{\mathrm {T}}}$ value of any two-jet system (middle right), the number of jets in the event (lower left), and the $ {{| \eta |}} $ of the recoiling jet (lower right). The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 3-d:
Distributions of the most powerful discriminating variables in the signal region: The scalar ${p_{\mathrm {T}}}$ sum of all jets (upper left), the maximum invariant mass of any two-jet system (upper right), the maximum DeepJet score of any jet (middle left), the maximum ${p_{\mathrm {T}}}$ value of any two-jet system (middle right), the number of jets in the event (lower left), and the $ {{| \eta |}} $ of the recoiling jet (lower right). The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 3-e:
Distributions of the most powerful discriminating variables in the signal region: The scalar ${p_{\mathrm {T}}}$ sum of all jets (upper left), the maximum invariant mass of any two-jet system (upper right), the maximum DeepJet score of any jet (middle left), the maximum ${p_{\mathrm {T}}}$ value of any two-jet system (middle right), the number of jets in the event (lower left), and the $ {{| \eta |}} $ of the recoiling jet (lower right). The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 3-f:
Distributions of the most powerful discriminating variables in the signal region: The scalar ${p_{\mathrm {T}}}$ sum of all jets (upper left), the maximum invariant mass of any two-jet system (upper right), the maximum DeepJet score of any jet (middle left), the maximum ${p_{\mathrm {T}}}$ value of any two-jet system (middle right), the number of jets in the event (lower left), and the $ {{| \eta |}} $ of the recoiling jet (lower right). The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 4:
Distributions in the WZ-enriched control region of the transverse mass of the W boson (upper left) and the number of selected jets (upper right). Distributions of the number of b-tagged jets in the ${{\mathrm{t} {}\mathrm{\bar{t}}}}$Z-enriched control region (lower left), and the number of jets in the ZZ-enriched control region (lower right). The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 4-a:
Distributions in the WZ-enriched control region of the transverse mass of the W boson (upper left) and the number of selected jets (upper right). Distributions of the number of b-tagged jets in the ${{\mathrm{t} {}\mathrm{\bar{t}}}}$Z-enriched control region (lower left), and the number of jets in the ZZ-enriched control region (lower right). The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 4-b:
Distributions in the WZ-enriched control region of the transverse mass of the W boson (upper left) and the number of selected jets (upper right). Distributions of the number of b-tagged jets in the ${{\mathrm{t} {}\mathrm{\bar{t}}}}$Z-enriched control region (lower left), and the number of jets in the ZZ-enriched control region (lower right). The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 4-c:
Distributions in the WZ-enriched control region of the transverse mass of the W boson (upper left) and the number of selected jets (upper right). Distributions of the number of b-tagged jets in the ${{\mathrm{t} {}\mathrm{\bar{t}}}}$Z-enriched control region (lower left), and the number of jets in the ZZ-enriched control region (lower right). The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 4-d:
Distributions in the WZ-enriched control region of the transverse mass of the W boson (upper left) and the number of selected jets (upper right). Distributions of the number of b-tagged jets in the ${{\mathrm{t} {}\mathrm{\bar{t}}}}$Z-enriched control region (lower left), and the number of jets in the ZZ-enriched control region (lower right). The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 5:
Distributions in the Z${\gamma} $-enriched control region of the number of selected muons (left) and the invariant mass of the three-lepton system (right) for the data and the MC simulation. The contributions in the simulation from "external'' photon conversions, where a real photon converts into a pair of (mostly) electrons from its interaction in the detector material, and so-called "internal'' conversions, where a virtual photon decays into a pair of leptons, are shown separately. The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 5-a:
Distributions in the Z${\gamma} $-enriched control region of the number of selected muons (left) and the invariant mass of the three-lepton system (right) for the data and the MC simulation. The contributions in the simulation from "external'' photon conversions, where a real photon converts into a pair of (mostly) electrons from its interaction in the detector material, and so-called "internal'' conversions, where a virtual photon decays into a pair of leptons, are shown separately. The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 5-b:
Distributions in the Z${\gamma} $-enriched control region of the number of selected muons (left) and the invariant mass of the three-lepton system (right) for the data and the MC simulation. The contributions in the simulation from "external'' photon conversions, where a real photon converts into a pair of (mostly) electrons from its interaction in the detector material, and so-called "internal'' conversions, where a virtual photon decays into a pair of leptons, are shown separately. The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 6:
Distributions of the number of selected muons per event (left) and the event BDT discriminant used for the signal extraction (right) in a control region enriched with nonprompt leptons. The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 6-a:
Distributions of the number of selected muons per event (left) and the event BDT discriminant used for the signal extraction (right) in a control region enriched with nonprompt leptons. The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 6-b:
Distributions of the number of selected muons per event (left) and the event BDT discriminant used for the signal extraction (right) in a control region enriched with nonprompt leptons. The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 7:
Distributions of the event BDT discriminant in the signal region for data (points) and from MC predictions (histograms). The results are shown for pre-fit (left) and post-fit (right) distributions in orthogonal event categories: exactly one b-tagged jet, 2-3 jets (upper); exactly one b-tagged jet, $\geq $4 jets (middle); $\geq $2 b-tagged jets (lower). The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 7-a:
Distributions of the event BDT discriminant in the signal region for data (points) and from MC predictions (histograms). The results are shown for pre-fit (left) and post-fit (right) distributions in orthogonal event categories: exactly one b-tagged jet, 2-3 jets (upper); exactly one b-tagged jet, $\geq $4 jets (middle); $\geq $2 b-tagged jets (lower). The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 7-b:
Distributions of the event BDT discriminant in the signal region for data (points) and from MC predictions (histograms). The results are shown for pre-fit (left) and post-fit (right) distributions in orthogonal event categories: exactly one b-tagged jet, 2-3 jets (upper); exactly one b-tagged jet, $\geq $4 jets (middle); $\geq $2 b-tagged jets (lower). The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 7-c:
Distributions of the event BDT discriminant in the signal region for data (points) and from MC predictions (histograms). The results are shown for pre-fit (left) and post-fit (right) distributions in orthogonal event categories: exactly one b-tagged jet, 2-3 jets (upper); exactly one b-tagged jet, $\geq $4 jets (middle); $\geq $2 b-tagged jets (lower). The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 7-d:
Distributions of the event BDT discriminant in the signal region for data (points) and from MC predictions (histograms). The results are shown for pre-fit (left) and post-fit (right) distributions in orthogonal event categories: exactly one b-tagged jet, 2-3 jets (upper); exactly one b-tagged jet, $\geq $4 jets (middle); $\geq $2 b-tagged jets (lower). The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 7-e:
Distributions of the event BDT discriminant in the signal region for data (points) and from MC predictions (histograms). The results are shown for pre-fit (left) and post-fit (right) distributions in orthogonal event categories: exactly one b-tagged jet, 2-3 jets (upper); exactly one b-tagged jet, $\geq $4 jets (middle); $\geq $2 b-tagged jets (lower). The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 7-f:
Distributions of the event BDT discriminant in the signal region for data (points) and from MC predictions (histograms). The results are shown for pre-fit (left) and post-fit (right) distributions in orthogonal event categories: exactly one b-tagged jet, 2-3 jets (upper); exactly one b-tagged jet, $\geq $4 jets (middle); $\geq $2 b-tagged jets (lower). The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 8:
Summary of the dominant systematic uncertainties affecting the inclusive tZq cross section measurement. The left column lists the sources of systematic uncertainty, treated as nuisance parameters in the fit, in order of importance. In the middle column, the black points with the horizontal bars show for each source the difference between the observed best-fit value ($\hat{\theta}$) and the nominal value ($\theta _0$), divided by the expected standard deviation ($\Delta \theta $). The right column plots the change in the tZq signal strength $\mu $ if a nuisance parameter is varied one standard deviation up (red), or down (blue). The gray, red and blue bands display the same quantity as their corresponding markers, but using a simulated data set where all nuisance parameters are set to their expected values. |
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Figure 9:
Distributions at the detector level of some of the important variables used in the tZq analysis for a tZq -enriched region. The selection criteria discussed in Section 4 have been used, along with the requirement that the event BDT discriminant be larger than 0.5. The variables shown are as follows: upper left: transverse momentum of the lepton associated with the decay of the top quark, upper right: number of muons in the event, lower left: reconstructed transverse momentum of the Z boson, lower right: transverse mass of the W boson. The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 9-a:
Distributions at the detector level of some of the important variables used in the tZq analysis for a tZq -enriched region. The selection criteria discussed in Section 4 have been used, along with the requirement that the event BDT discriminant be larger than 0.5. The variables shown are as follows: upper left: transverse momentum of the lepton associated with the decay of the top quark, upper right: number of muons in the event, lower left: reconstructed transverse momentum of the Z boson, lower right: transverse mass of the W boson. The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 9-b:
Distributions at the detector level of some of the important variables used in the tZq analysis for a tZq -enriched region. The selection criteria discussed in Section 4 have been used, along with the requirement that the event BDT discriminant be larger than 0.5. The variables shown are as follows: upper left: transverse momentum of the lepton associated with the decay of the top quark, upper right: number of muons in the event, lower left: reconstructed transverse momentum of the Z boson, lower right: transverse mass of the W boson. The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 9-c:
Distributions at the detector level of some of the important variables used in the tZq analysis for a tZq -enriched region. The selection criteria discussed in Section 4 have been used, along with the requirement that the event BDT discriminant be larger than 0.5. The variables shown are as follows: upper left: transverse momentum of the lepton associated with the decay of the top quark, upper right: number of muons in the event, lower left: reconstructed transverse momentum of the Z boson, lower right: transverse mass of the W boson. The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 9-d:
Distributions at the detector level of some of the important variables used in the tZq analysis for a tZq -enriched region. The selection criteria discussed in Section 4 have been used, along with the requirement that the event BDT discriminant be larger than 0.5. The variables shown are as follows: upper left: transverse momentum of the lepton associated with the decay of the top quark, upper right: number of muons in the event, lower left: reconstructed transverse momentum of the Z boson, lower right: transverse mass of the W boson. The lower panels show the ratio of the data to the predictions. The vertical lines on the data points represent the statistical uncertainty in the data; the shaded area corresponds to the total uncertainty in the prediction; the gray area in the ratio indicates the uncertainty related to the limited statistical precision in the prediction. |
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Figure 10:
Measured values of the inclusive tZq cross section signal strength $\mu $, the top quark and antiquark cross section signal strengths $\mu _{{{\mathrm{t}}{\mathrm{Z}}{\mathrm{q}} (\ell ^+_\mathrm {t})}}$ and $\mu _{{{\mathrm{\bar{t}}}{\mathrm{Z}}{\mathrm{q}} (\ell ^-_\mathrm {t})}}$, and their ratio $R$. The black points show the central values, while the blue and yellow bands refer to the statistical and total uncertainties, respectively. |
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Figure 11:
Response matrices of the ${{p_{\mathrm {T}}} (\mathrm{Z})}$ at parton level (left) and ${{p_{\mathrm {T}}} (\mathrm{t})}$ at particle level (right) for tZq events in the full and visible phase space, respectively. The expected number of reconstructed events is given for each bin. The color indicates the transition probability for an event in a generator-level bin, to have a reconstructed value corresponding to a given detector-level bin. The efficiency $\times $ acceptance values of reconstructing events are plotted in the middle panel. The lower panel shows the stability and purity values as they are defined in the text. |
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Figure 11-a:
Response matrices of the ${{p_{\mathrm {T}}} (\mathrm{Z})}$ at parton level (left) and ${{p_{\mathrm {T}}} (\mathrm{t})}$ at particle level (right) for tZq events in the full and visible phase space, respectively. The expected number of reconstructed events is given for each bin. The color indicates the transition probability for an event in a generator-level bin, to have a reconstructed value corresponding to a given detector-level bin. The efficiency $\times $ acceptance values of reconstructing events are plotted in the middle panel. The lower panel shows the stability and purity values as they are defined in the text. |
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Figure 11-b:
Response matrices of the ${{p_{\mathrm {T}}} (\mathrm{Z})}$ at parton level (left) and ${{p_{\mathrm {T}}} (\mathrm{t})}$ at particle level (right) for tZq events in the full and visible phase space, respectively. The expected number of reconstructed events is given for each bin. The color indicates the transition probability for an event in a generator-level bin, to have a reconstructed value corresponding to a given detector-level bin. The efficiency $\times $ acceptance values of reconstructing events are plotted in the middle panel. The lower panel shows the stability and purity values as they are defined in the text. |
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Figure 12:
Pre-fit (upper) and post-fit (lower) distributions of the neural network score of the tZq output node for events in the signal region with less than four jets, used for the ${{p_{\mathrm {T}}} (\mathrm {j}')}$ differential cross section measurement at particle level. The data are shown by the points and the MC predictions by the colored histograms. The vertical lines on the points represent the statistical uncertainty in the data, and the hatched region the total uncertainty in the prediction. The events are split into three subregions based on the value of ${{p_{\mathrm {T}}} (\mathrm{t})}$ measured at the detector level. Three different tZq templates, defined by the same values of ${{p_{\mathrm {T}}} (\mathrm {j}')}$ at particle level and shown in different shades of orange and red, are used to model the contribution of each particle-level bin. Reconstructed tZq events that are outside of the fiducial phase space are labeled as "${\mathrm{t}}{\mathrm{Z}}{\mathrm{q}}$ (others)'' and represent a minor contribution. The lower panels show the ratio of the data to the prediction, with the grey band indicating the uncertainty from the finite number of MC events. |
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Figure 12-a:
Pre-fit (upper) and post-fit (lower) distributions of the neural network score of the tZq output node for events in the signal region with less than four jets, used for the ${{p_{\mathrm {T}}} (\mathrm {j}')}$ differential cross section measurement at particle level. The data are shown by the points and the MC predictions by the colored histograms. The vertical lines on the points represent the statistical uncertainty in the data, and the hatched region the total uncertainty in the prediction. The events are split into three subregions based on the value of ${{p_{\mathrm {T}}} (\mathrm{t})}$ measured at the detector level. Three different tZq templates, defined by the same values of ${{p_{\mathrm {T}}} (\mathrm {j}')}$ at particle level and shown in different shades of orange and red, are used to model the contribution of each particle-level bin. Reconstructed tZq events that are outside of the fiducial phase space are labeled as "${\mathrm{t}}{\mathrm{Z}}{\mathrm{q}}$ (others)'' and represent a minor contribution. The lower panels show the ratio of the data to the prediction, with the grey band indicating the uncertainty from the finite number of MC events. |
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Figure 12-b:
Pre-fit (upper) and post-fit (lower) distributions of the neural network score of the tZq output node for events in the signal region with less than four jets, used for the ${{p_{\mathrm {T}}} (\mathrm {j}')}$ differential cross section measurement at particle level. The data are shown by the points and the MC predictions by the colored histograms. The vertical lines on the points represent the statistical uncertainty in the data, and the hatched region the total uncertainty in the prediction. The events are split into three subregions based on the value of ${{p_{\mathrm {T}}} (\mathrm{t})}$ measured at the detector level. Three different tZq templates, defined by the same values of ${{p_{\mathrm {T}}} (\mathrm {j}')}$ at particle level and shown in different shades of orange and red, are used to model the contribution of each particle-level bin. Reconstructed tZq events that are outside of the fiducial phase space are labeled as "${\mathrm{t}}{\mathrm{Z}}{\mathrm{q}}$ (others)'' and represent a minor contribution. The lower panels show the ratio of the data to the prediction, with the grey band indicating the uncertainty from the finite number of MC events. |
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Figure 13:
Pre-fit (upper) and post-fit (lower) distributions of the neural network score of the tZq output node for events in the signal region with less than four jets, used for the ${m(3\ell)}$ differential cross section measurement at parton level. The data are shown by the points and the MC predictions by the colored histograms. The vertical lines on the points represent the statistical uncertainty in the data, and the hatched region the total uncertainty in the prediction. The events are split into four subregions based on the value of ${{p_{\mathrm {T}}} (\mathrm{t})}$ measured at the detector level. Four different tZq templates, defined by the same values of ${m(3\ell)}$ at parton level and shown in different shades of orange and red, are used to model the contribution of each parton-level bin. The lower panels show the ratio of the data to the prediction, with the grey band indicating the uncertainty from the finite number of MC events. |
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Figure 13-a:
Pre-fit (upper) and post-fit (lower) distributions of the neural network score of the tZq output node for events in the signal region with less than four jets, used for the ${m(3\ell)}$ differential cross section measurement at parton level. The data are shown by the points and the MC predictions by the colored histograms. The vertical lines on the points represent the statistical uncertainty in the data, and the hatched region the total uncertainty in the prediction. The events are split into four subregions based on the value of ${{p_{\mathrm {T}}} (\mathrm{t})}$ measured at the detector level. Four different tZq templates, defined by the same values of ${m(3\ell)}$ at parton level and shown in different shades of orange and red, are used to model the contribution of each parton-level bin. The lower panels show the ratio of the data to the prediction, with the grey band indicating the uncertainty from the finite number of MC events. |
png pdf |
Figure 13-b:
Pre-fit (upper) and post-fit (lower) distributions of the neural network score of the tZq output node for events in the signal region with less than four jets, used for the ${m(3\ell)}$ differential cross section measurement at parton level. The data are shown by the points and the MC predictions by the colored histograms. The vertical lines on the points represent the statistical uncertainty in the data, and the hatched region the total uncertainty in the prediction. The events are split into four subregions based on the value of ${{p_{\mathrm {T}}} (\mathrm{t})}$ measured at the detector level. Four different tZq templates, defined by the same values of ${m(3\ell)}$ at parton level and shown in different shades of orange and red, are used to model the contribution of each parton-level bin. The lower panels show the ratio of the data to the prediction, with the grey band indicating the uncertainty from the finite number of MC events. |
png pdf |
Figure 14:
Absolute differential cross sections as a function of ${{p_{\mathrm {T}}} (\mathrm{Z})}$ measured at parton (upper left) and particle levels (upper right), as well as a function of ${{p_{\mathrm {T}}} (\mathrm {j}')}$ (lower left) and ${{{| \eta |}} (\mathrm {j}')}$ (lower right) at particle level. The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 14-a:
Absolute differential cross sections as a function of ${{p_{\mathrm {T}}} (\mathrm{Z})}$ measured at parton (upper left) and particle levels (upper right), as well as a function of ${{p_{\mathrm {T}}} (\mathrm {j}')}$ (lower left) and ${{{| \eta |}} (\mathrm {j}')}$ (lower right) at particle level. The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 14-b:
Absolute differential cross sections as a function of ${{p_{\mathrm {T}}} (\mathrm{Z})}$ measured at parton (upper left) and particle levels (upper right), as well as a function of ${{p_{\mathrm {T}}} (\mathrm {j}')}$ (lower left) and ${{{| \eta |}} (\mathrm {j}')}$ (lower right) at particle level. The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 14-c:
Absolute differential cross sections as a function of ${{p_{\mathrm {T}}} (\mathrm{Z})}$ measured at parton (upper left) and particle levels (upper right), as well as a function of ${{p_{\mathrm {T}}} (\mathrm {j}')}$ (lower left) and ${{{| \eta |}} (\mathrm {j}')}$ (lower right) at particle level. The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 14-d:
Absolute differential cross sections as a function of ${{p_{\mathrm {T}}} (\mathrm{Z})}$ measured at parton (upper left) and particle levels (upper right), as well as a function of ${{p_{\mathrm {T}}} (\mathrm {j}')}$ (lower left) and ${{{| \eta |}} (\mathrm {j}')}$ (lower right) at particle level. The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 15:
Absolute differential cross sections at parton (left) and particle level (right) measured as a function of ${\Delta \phi (\ell,\ell ')}$ (upper), ${{p_{\mathrm {T}}} (\ell _{\mathrm{t}})}$ (middle) and ${m(3\ell)}$ (lower). The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 15-a:
Absolute differential cross sections at parton (left) and particle level (right) measured as a function of ${\Delta \phi (\ell,\ell ')}$ (upper), ${{p_{\mathrm {T}}} (\ell _{\mathrm{t}})}$ (middle) and ${m(3\ell)}$ (lower). The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 15-b:
Absolute differential cross sections at parton (left) and particle level (right) measured as a function of ${\Delta \phi (\ell,\ell ')}$ (upper), ${{p_{\mathrm {T}}} (\ell _{\mathrm{t}})}$ (middle) and ${m(3\ell)}$ (lower). The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 15-c:
Absolute differential cross sections at parton (left) and particle level (right) measured as a function of ${\Delta \phi (\ell,\ell ')}$ (upper), ${{p_{\mathrm {T}}} (\ell _{\mathrm{t}})}$ (middle) and ${m(3\ell)}$ (lower). The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 15-d:
Absolute differential cross sections at parton (left) and particle level (right) measured as a function of ${\Delta \phi (\ell,\ell ')}$ (upper), ${{p_{\mathrm {T}}} (\ell _{\mathrm{t}})}$ (middle) and ${m(3\ell)}$ (lower). The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 15-e:
Absolute differential cross sections at parton (left) and particle level (right) measured as a function of ${\Delta \phi (\ell,\ell ')}$ (upper), ${{p_{\mathrm {T}}} (\ell _{\mathrm{t}})}$ (middle) and ${m(3\ell)}$ (lower). The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 15-f:
Absolute differential cross sections at parton (left) and particle level (right) measured as a function of ${\Delta \phi (\ell,\ell ')}$ (upper), ${{p_{\mathrm {T}}} (\ell _{\mathrm{t}})}$ (middle) and ${m(3\ell)}$ (lower). The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 16:
Absolute differential cross sections at parton (left) and particle level (right) measured as a function of ${{p_{\mathrm {T}}} (\mathrm{t})}$ (upper), ${m(\mathrm{t},\mathrm{Z})}$ (middle) and ${\cos(\theta ^{\star}_{\text {pol}})}$ (lower). The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 16-a:
Absolute differential cross sections at parton (left) and particle level (right) measured as a function of ${{p_{\mathrm {T}}} (\mathrm{t})}$ (upper), ${m(\mathrm{t},\mathrm{Z})}$ (middle) and ${\cos(\theta ^{\star}_{\text {pol}})}$ (lower). The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 16-b:
Absolute differential cross sections at parton (left) and particle level (right) measured as a function of ${{p_{\mathrm {T}}} (\mathrm{t})}$ (upper), ${m(\mathrm{t},\mathrm{Z})}$ (middle) and ${\cos(\theta ^{\star}_{\text {pol}})}$ (lower). The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 16-c:
Absolute differential cross sections at parton (left) and particle level (right) measured as a function of ${{p_{\mathrm {T}}} (\mathrm{t})}$ (upper), ${m(\mathrm{t},\mathrm{Z})}$ (middle) and ${\cos(\theta ^{\star}_{\text {pol}})}$ (lower). The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 16-d:
Absolute differential cross sections at parton (left) and particle level (right) measured as a function of ${{p_{\mathrm {T}}} (\mathrm{t})}$ (upper), ${m(\mathrm{t},\mathrm{Z})}$ (middle) and ${\cos(\theta ^{\star}_{\text {pol}})}$ (lower). The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 16-e:
Absolute differential cross sections at parton (left) and particle level (right) measured as a function of ${{p_{\mathrm {T}}} (\mathrm{t})}$ (upper), ${m(\mathrm{t},\mathrm{Z})}$ (middle) and ${\cos(\theta ^{\star}_{\text {pol}})}$ (lower). The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 16-f:
Absolute differential cross sections at parton (left) and particle level (right) measured as a function of ${{p_{\mathrm {T}}} (\mathrm{t})}$ (upper), ${m(\mathrm{t},\mathrm{Z})}$ (middle) and ${\cos(\theta ^{\star}_{\text {pol}})}$ (lower). The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 17:
Normalized differential cross sections measured as a function of ${{p_{\mathrm {T}}} (\mathrm{Z})}$ at parton (upper left) and particle level (upper right), as well as a function of ${{p_{\mathrm {T}}} (\mathrm {j}')}$ (lower left) and ${{{| \eta |}} (\mathrm {j}')}$ (lower right) at particle level. The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 17-a:
Normalized differential cross sections measured as a function of ${{p_{\mathrm {T}}} (\mathrm{Z})}$ at parton (upper left) and particle level (upper right), as well as a function of ${{p_{\mathrm {T}}} (\mathrm {j}')}$ (lower left) and ${{{| \eta |}} (\mathrm {j}')}$ (lower right) at particle level. The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 17-b:
Normalized differential cross sections measured as a function of ${{p_{\mathrm {T}}} (\mathrm{Z})}$ at parton (upper left) and particle level (upper right), as well as a function of ${{p_{\mathrm {T}}} (\mathrm {j}')}$ (lower left) and ${{{| \eta |}} (\mathrm {j}')}$ (lower right) at particle level. The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 17-c:
Normalized differential cross sections measured as a function of ${{p_{\mathrm {T}}} (\mathrm{Z})}$ at parton (upper left) and particle level (upper right), as well as a function of ${{p_{\mathrm {T}}} (\mathrm {j}')}$ (lower left) and ${{{| \eta |}} (\mathrm {j}')}$ (lower right) at particle level. The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 17-d:
Normalized differential cross sections measured as a function of ${{p_{\mathrm {T}}} (\mathrm{Z})}$ at parton (upper left) and particle level (upper right), as well as a function of ${{p_{\mathrm {T}}} (\mathrm {j}')}$ (lower left) and ${{{| \eta |}} (\mathrm {j}')}$ (lower right) at particle level. The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 18:
Normalized differential cross sections measured at parton (left) and particle level (right) as a function of ${\Delta \phi (\ell,\ell ')}$ (upper), ${{p_{\mathrm {T}}} (\ell _{\mathrm{t}})}$ (middle) and ${m(3\ell)}$ (lower). The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 18-a:
Normalized differential cross sections measured at parton (left) and particle level (right) as a function of ${\Delta \phi (\ell,\ell ')}$ (upper), ${{p_{\mathrm {T}}} (\ell _{\mathrm{t}})}$ (middle) and ${m(3\ell)}$ (lower). The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 18-b:
Normalized differential cross sections measured at parton (left) and particle level (right) as a function of ${\Delta \phi (\ell,\ell ')}$ (upper), ${{p_{\mathrm {T}}} (\ell _{\mathrm{t}})}$ (middle) and ${m(3\ell)}$ (lower). The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 18-c:
Normalized differential cross sections measured at parton (left) and particle level (right) as a function of ${\Delta \phi (\ell,\ell ')}$ (upper), ${{p_{\mathrm {T}}} (\ell _{\mathrm{t}})}$ (middle) and ${m(3\ell)}$ (lower). The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 18-d:
Normalized differential cross sections measured at parton (left) and particle level (right) as a function of ${\Delta \phi (\ell,\ell ')}$ (upper), ${{p_{\mathrm {T}}} (\ell _{\mathrm{t}})}$ (middle) and ${m(3\ell)}$ (lower). The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 18-e:
Normalized differential cross sections measured at parton (left) and particle level (right) as a function of ${\Delta \phi (\ell,\ell ')}$ (upper), ${{p_{\mathrm {T}}} (\ell _{\mathrm{t}})}$ (middle) and ${m(3\ell)}$ (lower). The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 18-f:
Normalized differential cross sections measured at parton (left) and particle level (right) as a function of ${\Delta \phi (\ell,\ell ')}$ (upper), ${{p_{\mathrm {T}}} (\ell _{\mathrm{t}})}$ (middle) and ${m(3\ell)}$ (lower). The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 19:
Normalized differential cross sections measured at parton (left) and particle level (right) as a function of ${{p_{\mathrm {T}}} (\mathrm{t})}$ (upper), ${m(\mathrm{t},\mathrm{Z})}$ (middle) and ${\cos(\theta ^{\star}_{\text {pol}})}$ (lower). The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 19-a:
Normalized differential cross sections measured at parton (left) and particle level (right) as a function of ${{p_{\mathrm {T}}} (\mathrm{t})}$ (upper), ${m(\mathrm{t},\mathrm{Z})}$ (middle) and ${\cos(\theta ^{\star}_{\text {pol}})}$ (lower). The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 19-b:
Normalized differential cross sections measured at parton (left) and particle level (right) as a function of ${{p_{\mathrm {T}}} (\mathrm{t})}$ (upper), ${m(\mathrm{t},\mathrm{Z})}$ (middle) and ${\cos(\theta ^{\star}_{\text {pol}})}$ (lower). The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 19-c:
Normalized differential cross sections measured at parton (left) and particle level (right) as a function of ${{p_{\mathrm {T}}} (\mathrm{t})}$ (upper), ${m(\mathrm{t},\mathrm{Z})}$ (middle) and ${\cos(\theta ^{\star}_{\text {pol}})}$ (lower). The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 19-d:
Normalized differential cross sections measured at parton (left) and particle level (right) as a function of ${{p_{\mathrm {T}}} (\mathrm{t})}$ (upper), ${m(\mathrm{t},\mathrm{Z})}$ (middle) and ${\cos(\theta ^{\star}_{\text {pol}})}$ (lower). The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 19-e:
Normalized differential cross sections measured at parton (left) and particle level (right) as a function of ${{p_{\mathrm {T}}} (\mathrm{t})}$ (upper), ${m(\mathrm{t},\mathrm{Z})}$ (middle) and ${\cos(\theta ^{\star}_{\text {pol}})}$ (lower). The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 19-f:
Normalized differential cross sections measured at parton (left) and particle level (right) as a function of ${{p_{\mathrm {T}}} (\mathrm{t})}$ (upper), ${m(\mathrm{t},\mathrm{Z})}$ (middle) and ${\cos(\theta ^{\star}_{\text {pol}})}$ (lower). The observed values are shown as black points with the inner and outer vertical bars giving the systematic and total uncertainties, respectively. The SM predictions for the tZq process are based on events simulated in the 5FS (green) and 4FS (blue) and the $p$-values of $\chi ^2$ tests are given to quantify their compatibility with the measurement. The lower panels show the ratio of the MC prediction to the measurement. |
png pdf |
Figure 20:
Pre-fit (upper) and post-fit (lower) distributions of the neural network score of the tZq output node for events in the signal region with less than four jets, used for the measurement of the spin asymmetry from ${\cos(\theta ^{\star}_{\text {pol}})}$ at parton level. The data are shown by the points and the MC predictions by the colored histograms. The vertical lines on the points represent the statistical uncertainty in the data, and the hatched region the total uncertainty in the prediction. The events are split into three subregions based on the value of ${{p_{\mathrm {T}}} (\mathrm{t})}$ measured at the detector level. Three different tZq templates, defined by the same values of ${\cos(\theta ^{\star}_{\text {pol}})}$ at parton level and shown in different shades of orange and red, are used to model the contribution of each parton-level bin. The lower panels show the ratio of the data to the prediction, with the grey band indicating the uncertainty from the finite number of MC events. |
png pdf |
Figure 20-a:
Pre-fit (upper) and post-fit (lower) distributions of the neural network score of the tZq output node for events in the signal region with less than four jets, used for the measurement of the spin asymmetry from ${\cos(\theta ^{\star}_{\text {pol}})}$ at parton level. The data are shown by the points and the MC predictions by the colored histograms. The vertical lines on the points represent the statistical uncertainty in the data, and the hatched region the total uncertainty in the prediction. The events are split into three subregions based on the value of ${{p_{\mathrm {T}}} (\mathrm{t})}$ measured at the detector level. Three different tZq templates, defined by the same values of ${\cos(\theta ^{\star}_{\text {pol}})}$ at parton level and shown in different shades of orange and red, are used to model the contribution of each parton-level bin. The lower panels show the ratio of the data to the prediction, with the grey band indicating the uncertainty from the finite number of MC events. |
png pdf |
Figure 20-b:
Pre-fit (upper) and post-fit (lower) distributions of the neural network score of the tZq output node for events in the signal region with less than four jets, used for the measurement of the spin asymmetry from ${\cos(\theta ^{\star}_{\text {pol}})}$ at parton level. The data are shown by the points and the MC predictions by the colored histograms. The vertical lines on the points represent the statistical uncertainty in the data, and the hatched region the total uncertainty in the prediction. The events are split into three subregions based on the value of ${{p_{\mathrm {T}}} (\mathrm{t})}$ measured at the detector level. Three different tZq templates, defined by the same values of ${\cos(\theta ^{\star}_{\text {pol}})}$ at parton level and shown in different shades of orange and red, are used to model the contribution of each parton-level bin. The lower panels show the ratio of the data to the prediction, with the grey band indicating the uncertainty from the finite number of MC events. |
| Tables | |
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Table 1:
Summary of the $p$-values of the $\chi ^2$ test between the unfolded measurements and theoretical predictions from the 4FS and 5FS. The test is performed on the measurements of the absolute and normalized differential cross sections at parton and particle level for the various observables used in this note. All numbers are given in percentage. |
| Summary |
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Inclusive and differential cross section measurements of single top quark production in association with a Z boson (tZq) are presented using events with three leptons (electrons or muons). The data sample collected by the CMS experiment at the LHC in proton-proton collisions at a center-of-mass energy of 13 TeV corresponds to an integrated luminosity of 138 fb$^{-1}$}. Including nonresonant dilepton pairs, an inclusive cross section of $ \sigma_{\mathrm{tZq}} = $ 87.9 ${}_{-7.3}^{+7.5}$ (stat) ${}_{-6.0}^{+7.3}$ (syst) fb is obtained for ${m_{\ell\ell'}} > $ 30 GeV. This result represents the most precise inclusive tZq cross section measurement to date, leading to an improvement in relative precision of about 30% with respect to the previously published results. For the first time, the inclusive tZq cross sections are also measured separately for top quark and antiquark production, obtaining $ \sigma_{{\mathrm{tZq}} (\ell^+_\mathrm{t})}= $ 62.2 ${}_{-5.7}^{+5.9}$ (stat) ${}_{-3.7}^{+4.4}$ (syst) fb and $ \sigma_{{\mathrm{\bar{t}Zq} (\ell^-_\mathrm{t})} } = $ 26.1 ${}_{-4.6}^{+4.8}$ (stat) ${}_{-2.8}^{+3.0}$ (syst) fb, respectively, with the ratio of 2.37 ${}_{-0.42}^{+0.56}$ (stat) ${}_{-0.13}^{+0.27}$ (syst). The differential tZq cross sections are measured for the first time at parton and particle levels using a binned maximum likelihood-based unfolding. The studied observables are the transverse momenta of the top quark, the Z boson, and the lepton associated with the top quark decay, as well as the invariant masses of the three leptons and the top-Z system. Also used as observables are the difference in azimuthal angle between the two leptons from the Z boson decay, the cosine of the top quark polarization angle, and, at particle level, the transverse momentum and absolute pseudorapidity of the jet associated with the spectator quark. The results are mostly compatible with the standard model predictions using both the four- and five-flavor schemes. From the differential distribution of the top quark polarization angle, the top quark spin asymmetry is measured to be $A_{\ell} = $ 0.58 ${}^{+0.15}_{-0.16}$ (stat) $\pm$ 0.06 (syst), in agreement with the standard model prediction. |
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Compact Muon Solenoid LHC, CERN |
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