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| CMS-PAS-TOP-23-008 | ||
| Measurement of inclusive and differential cross sections for single top quark production in association with a W boson in proton-proton collisions at $ \sqrt{s}= $ 13.6 TeV | ||
| CMS Collaboration | ||
| 27 March 2024 | ||
| Abstract: The first measurement of the inclusive and normalised differential cross sections for the production of single top quarks in association with a W boson in proton-proton collisions at a centre-of-mass energy of 13.6 TeV are presented. The data used were recorded with the CMS detector at the LHC during 2022, and correspond to an integrated luminosity of 34.7 fb$^{-1}$. The analyzed events contain one muon and one electron in the final state. For the inclusive measurement, multivariate discriminants are used exploiting the kinematic properties of the events to separate the signal from the dominant top quark antiquark production background. A cross section of 84.1 $ \pm $ 2.1 (stat) $^{+9.8}_{-10.2}$ (syst) $\pm$ 3.3 (lumi) pb is obtained, consistent with the predictions of the standard model. A fiducial region is defined according to the detector acceptance for performing the differential measurements. The resulting differential distributions are unfolded to particle level and show good agreement with the predictions at next-to-leading order in perturbative quantum chromodynamics. | ||
| Links: CDS record (PDF) ; Physics Briefing ; CADI line (restricted) ; | ||
| Figures | |
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Figure 1:
Leading-order Feynman diagrams for single top quark production in the $ \mathrm{t}\mathrm{W} $ mode. The charge-conjugate modes are implicitly included. |
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Figure 1-a:
Leading-order Feynman diagrams for single top quark production in the $ \mathrm{t}\mathrm{W} $ mode. The charge-conjugate modes are implicitly included. |
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Figure 1-b:
Leading-order Feynman diagrams for single top quark production in the $ \mathrm{t}\mathrm{W} $ mode. The charge-conjugate modes are implicitly included. |
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Figure 2:
Feynman diagrams for $ \mathrm{t}\mathrm{W} $ single top quark production at NLO that are removed from the signal definition in the DR scheme. The charge-conjugate modes are implicitly included. |
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Figure 2-a:
Feynman diagrams for $ \mathrm{t}\mathrm{W} $ single top quark production at NLO that are removed from the signal definition in the DR scheme. The charge-conjugate modes are implicitly included. |
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Figure 2-b:
Feynman diagrams for $ \mathrm{t}\mathrm{W} $ single top quark production at NLO that are removed from the signal definition in the DR scheme. The charge-conjugate modes are implicitly included. |
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Figure 2-c:
Feynman diagrams for $ \mathrm{t}\mathrm{W} $ single top quark production at NLO that are removed from the signal definition in the DR scheme. The charge-conjugate modes are implicitly included. |
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Figure 3:
Left: the number of events observed in data (points) and predicted from simulation (filled histograms) in the $ \mathrm{e}^\pm\mu^\mp $ sample as a function of the number of jets and b-tagged jets before the maximum likelihood fit. Right: the number of loose jets per event in the $ \mathrm{e}^\pm\mu^\mp $ sample from the 1j1b region before the maximum likelihood fit. The vertical bars on the points show the statistical uncertainties in the data. The hatched band represents the sum of the statistical and systematic uncertainties in the MC predictions. The lower panels show the ratio of data to the sum of the expected yields. |
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Figure 3-a:
Left: the number of events observed in data (points) and predicted from simulation (filled histograms) in the $ \mathrm{e}^\pm\mu^\mp $ sample as a function of the number of jets and b-tagged jets before the maximum likelihood fit. Right: the number of loose jets per event in the $ \mathrm{e}^\pm\mu^\mp $ sample from the 1j1b region before the maximum likelihood fit. The vertical bars on the points show the statistical uncertainties in the data. The hatched band represents the sum of the statistical and systematic uncertainties in the MC predictions. The lower panels show the ratio of data to the sum of the expected yields. |
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Figure 3-b:
Left: the number of events observed in data (points) and predicted from simulation (filled histograms) in the $ \mathrm{e}^\pm\mu^\mp $ sample as a function of the number of jets and b-tagged jets before the maximum likelihood fit. Right: the number of loose jets per event in the $ \mathrm{e}^\pm\mu^\mp $ sample from the 1j1b region before the maximum likelihood fit. The vertical bars on the points show the statistical uncertainties in the data. The hatched band represents the sum of the statistical and systematic uncertainties in the MC predictions. The lower panels show the ratio of data to the sum of the expected yields. |
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Figure 4:
Distributions from data (points) and MC simulations (filled histograms) before the maximum likelihood fit of the four most discriminating variables used for the RF training of the 1j1b region: (upper left) the $ p_{\mathrm{T}} $ of the leading loose jet; (upper right) the $ p_{\mathrm{T}} $ of the leading lepton; (lower left) the magnitude of the transverse momentum of the dilepton + jet system; and (lower right) the invariant mass of the dilepton system. The last bin of each distribution includes the overflow events, except for the leading loose jet $ p_{\mathrm{T}} $ distribution, which is only defined up to 30 GeV. The first bin in the upper left plot contains events with 0 loose jets. The vertical bars on the points give the statistical uncertainty in the data, and the hatched band represents the sum of the statistical and systematic uncertainties in the MC predictions. The lower panels show the ratio of the data to the sum of the MC predictions. |
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Figure 4-a:
Distributions from data (points) and MC simulations (filled histograms) before the maximum likelihood fit of the four most discriminating variables used for the RF training of the 1j1b region: (upper left) the $ p_{\mathrm{T}} $ of the leading loose jet; (upper right) the $ p_{\mathrm{T}} $ of the leading lepton; (lower left) the magnitude of the transverse momentum of the dilepton + jet system; and (lower right) the invariant mass of the dilepton system. The last bin of each distribution includes the overflow events, except for the leading loose jet $ p_{\mathrm{T}} $ distribution, which is only defined up to 30 GeV. The first bin in the upper left plot contains events with 0 loose jets. The vertical bars on the points give the statistical uncertainty in the data, and the hatched band represents the sum of the statistical and systematic uncertainties in the MC predictions. The lower panels show the ratio of the data to the sum of the MC predictions. |
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Figure 4-b:
Distributions from data (points) and MC simulations (filled histograms) before the maximum likelihood fit of the four most discriminating variables used for the RF training of the 1j1b region: (upper left) the $ p_{\mathrm{T}} $ of the leading loose jet; (upper right) the $ p_{\mathrm{T}} $ of the leading lepton; (lower left) the magnitude of the transverse momentum of the dilepton + jet system; and (lower right) the invariant mass of the dilepton system. The last bin of each distribution includes the overflow events, except for the leading loose jet $ p_{\mathrm{T}} $ distribution, which is only defined up to 30 GeV. The first bin in the upper left plot contains events with 0 loose jets. The vertical bars on the points give the statistical uncertainty in the data, and the hatched band represents the sum of the statistical and systematic uncertainties in the MC predictions. The lower panels show the ratio of the data to the sum of the MC predictions. |
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Figure 4-c:
Distributions from data (points) and MC simulations (filled histograms) before the maximum likelihood fit of the four most discriminating variables used for the RF training of the 1j1b region: (upper left) the $ p_{\mathrm{T}} $ of the leading loose jet; (upper right) the $ p_{\mathrm{T}} $ of the leading lepton; (lower left) the magnitude of the transverse momentum of the dilepton + jet system; and (lower right) the invariant mass of the dilepton system. The last bin of each distribution includes the overflow events, except for the leading loose jet $ p_{\mathrm{T}} $ distribution, which is only defined up to 30 GeV. The first bin in the upper left plot contains events with 0 loose jets. The vertical bars on the points give the statistical uncertainty in the data, and the hatched band represents the sum of the statistical and systematic uncertainties in the MC predictions. The lower panels show the ratio of the data to the sum of the MC predictions. |
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Figure 4-d:
Distributions from data (points) and MC simulations (filled histograms) before the maximum likelihood fit of the four most discriminating variables used for the RF training of the 1j1b region: (upper left) the $ p_{\mathrm{T}} $ of the leading loose jet; (upper right) the $ p_{\mathrm{T}} $ of the leading lepton; (lower left) the magnitude of the transverse momentum of the dilepton + jet system; and (lower right) the invariant mass of the dilepton system. The last bin of each distribution includes the overflow events, except for the leading loose jet $ p_{\mathrm{T}} $ distribution, which is only defined up to 30 GeV. The first bin in the upper left plot contains events with 0 loose jets. The vertical bars on the points give the statistical uncertainty in the data, and the hatched band represents the sum of the statistical and systematic uncertainties in the MC predictions. The lower panels show the ratio of the data to the sum of the MC predictions. |
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Figure 5:
The measured distributions from data (points) and MC simulations (filled histograms) before the maximum likelihood fit of the six observables used to measure the $ \mathrm{t}\mathrm{W} $ differential cross sections. Signal events in the 1j1b region with 0 loose jets (0 $ \mathrm{j}_{\text{l}} $) are selected. The last bin of each distribution contains the overflow events. The vertical bars on the data show the statistical uncertainty. The hatched band displays the sum of the statistical and systematic uncertainties in the MC predictions. The lower panels show the ratio of the data to the sum of the MC expectations. |
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Figure 5-a:
The measured distributions from data (points) and MC simulations (filled histograms) before the maximum likelihood fit of the six observables used to measure the $ \mathrm{t}\mathrm{W} $ differential cross sections. Signal events in the 1j1b region with 0 loose jets (0 $ \mathrm{j}_{\text{l}} $) are selected. The last bin of each distribution contains the overflow events. The vertical bars on the data show the statistical uncertainty. The hatched band displays the sum of the statistical and systematic uncertainties in the MC predictions. The lower panels show the ratio of the data to the sum of the MC expectations. |
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Figure 5-b:
The measured distributions from data (points) and MC simulations (filled histograms) before the maximum likelihood fit of the six observables used to measure the $ \mathrm{t}\mathrm{W} $ differential cross sections. Signal events in the 1j1b region with 0 loose jets (0 $ \mathrm{j}_{\text{l}} $) are selected. The last bin of each distribution contains the overflow events. The vertical bars on the data show the statistical uncertainty. The hatched band displays the sum of the statistical and systematic uncertainties in the MC predictions. The lower panels show the ratio of the data to the sum of the MC expectations. |
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Figure 5-c:
The measured distributions from data (points) and MC simulations (filled histograms) before the maximum likelihood fit of the six observables used to measure the $ \mathrm{t}\mathrm{W} $ differential cross sections. Signal events in the 1j1b region with 0 loose jets (0 $ \mathrm{j}_{\text{l}} $) are selected. The last bin of each distribution contains the overflow events. The vertical bars on the data show the statistical uncertainty. The hatched band displays the sum of the statistical and systematic uncertainties in the MC predictions. The lower panels show the ratio of the data to the sum of the MC expectations. |
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Figure 5-d:
The measured distributions from data (points) and MC simulations (filled histograms) before the maximum likelihood fit of the six observables used to measure the $ \mathrm{t}\mathrm{W} $ differential cross sections. Signal events in the 1j1b region with 0 loose jets (0 $ \mathrm{j}_{\text{l}} $) are selected. The last bin of each distribution contains the overflow events. The vertical bars on the data show the statistical uncertainty. The hatched band displays the sum of the statistical and systematic uncertainties in the MC predictions. The lower panels show the ratio of the data to the sum of the MC expectations. |
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Figure 5-e:
The measured distributions from data (points) and MC simulations (filled histograms) before the maximum likelihood fit of the six observables used to measure the $ \mathrm{t}\mathrm{W} $ differential cross sections. Signal events in the 1j1b region with 0 loose jets (0 $ \mathrm{j}_{\text{l}} $) are selected. The last bin of each distribution contains the overflow events. The vertical bars on the data show the statistical uncertainty. The hatched band displays the sum of the statistical and systematic uncertainties in the MC predictions. The lower panels show the ratio of the data to the sum of the MC expectations. |
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Figure 5-f:
The measured distributions from data (points) and MC simulations (filled histograms) before the maximum likelihood fit of the six observables used to measure the $ \mathrm{t}\mathrm{W} $ differential cross sections. Signal events in the 1j1b region with 0 loose jets (0 $ \mathrm{j}_{\text{l}} $) are selected. The last bin of each distribution contains the overflow events. The vertical bars on the data show the statistical uncertainty. The hatched band displays the sum of the statistical and systematic uncertainties in the MC predictions. The lower panels show the ratio of the data to the sum of the MC expectations. |
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Figure 6:
The distributions of the RF outputs for events in the 1j1b (upper left) and 2j1b (upper right) regions, and the subleading jet $ p_{\mathrm{T}} $ for the 2j2b region (lower). The data (points) and the MC predictions (filled histograms) after the maximum likelihood fit are shown. The vertical bars on the points represent the statistical uncertainty in the data, and the hatched band the total uncertainty in the MC prediction. The lower panels display the ratio of the data to the sum of the MC (points) predictions after the fit, with the bands giving the corresponding uncertainties. |
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Figure 6-a:
The distributions of the RF outputs for events in the 1j1b (upper left) and 2j1b (upper right) regions, and the subleading jet $ p_{\mathrm{T}} $ for the 2j2b region (lower). The data (points) and the MC predictions (filled histograms) after the maximum likelihood fit are shown. The vertical bars on the points represent the statistical uncertainty in the data, and the hatched band the total uncertainty in the MC prediction. The lower panels display the ratio of the data to the sum of the MC (points) predictions after the fit, with the bands giving the corresponding uncertainties. |
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Figure 6-b:
The distributions of the RF outputs for events in the 1j1b (upper left) and 2j1b (upper right) regions, and the subleading jet $ p_{\mathrm{T}} $ for the 2j2b region (lower). The data (points) and the MC predictions (filled histograms) after the maximum likelihood fit are shown. The vertical bars on the points represent the statistical uncertainty in the data, and the hatched band the total uncertainty in the MC prediction. The lower panels display the ratio of the data to the sum of the MC (points) predictions after the fit, with the bands giving the corresponding uncertainties. |
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Figure 6-c:
The distributions of the RF outputs for events in the 1j1b (upper left) and 2j1b (upper right) regions, and the subleading jet $ p_{\mathrm{T}} $ for the 2j2b region (lower). The data (points) and the MC predictions (filled histograms) after the maximum likelihood fit are shown. The vertical bars on the points represent the statistical uncertainty in the data, and the hatched band the total uncertainty in the MC prediction. The lower panels display the ratio of the data to the sum of the MC (points) predictions after the fit, with the bands giving the corresponding uncertainties. |
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Figure 7:
The $ \mathrm{t}\mathrm{W} $ cross section as a function of $ \sqrt{s} $, as obtained in this analysis (red filled circle) and in previous measurements by the CMS experiment [22,4,28,29 ] (black markers), with vertical bars on the markers indicating the total uncertainty in the measurements. Points corresponding to measurements at the same $ \sqrt{s} $ are horizontally shifted for better visibility. The SM prediction [15,16,17] is shown with a black line and blue uncertainty bands. |
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Figure 8:
The twenty largest impacts $ \Delta\hat{\mu} $ (right column) and fit constraints $ (\hat{\theta}-\theta_0)/\Delta\theta $ (middle column) of the nuisance parameters listed in the left column from the ML fit used to determine the inclusive $ \mathrm{t}\mathrm{W} $ cross section. The horizontal bars on the fit constraints show the ratio of the uncertainties of the fit result to the previous ones, effectively giving the constraint on the nuisance parameter. If the period is specified alongside the uncertainty name, it indicates that this is the component of the uncertainty uncorrelated by periods. There are two possible periods, before (2022PreEE) and after (2022PostEE) ECAL water leak. The JES uncertainties are divided into several sources, where ``JES - absolute'' groups contributions from scale corrections in the barrel, pileup corrections, and initial- and final-state radiation corrections; ``JES - relative sample'' encodes the uncertainty in the $ \eta $-dependent calibration of the jets; ``JES - BBEC1'' refers to pileup removal in the barrel (BB) and the first part of the endcaps (1.3 $ < |\eta| < $ 2.5; EC1) and also a contribution from scale corrections in the barrel; and ``JES - flavour QCD'' comes from the corrections applied to correct the different detector response to gluon and quark jets. This last uncertainty is split by jet flavour in three components. These components are: light for the gluon and up, down and strange quark jets, charm for the c jets and bottom for the b jets. |
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Figure 9:
Normalised fiducial differential $ \mathrm{t}\mathrm{W} $ production cross section as functions of the $ p_{\mathrm{T}} $ of the leading lepton (upper left), $ p_\mathrm{z}(\mathrm{e}^\pm, \mu^\mp, j) $ (upper right), $ p_{\mathrm{T}} $ of the jet (middle left), $ m(\mathrm{e}^\pm, \mu^\mp, j) $ (middle right), $ \Delta\varphi(\mathrm{e}^\pm, \mu^\mp) $ (lower left), and $ m_{\mathrm{T}}(\mathrm{e}^\pm, \mu^\mp, j, {\vec p}_{\mathrm{T}}^{\kern1pt\text{miss}}) $ (lower right). The vertical bars on the points give the statistical uncertainty in the data, the horizontal bars show the bin width. Predictions from POWHEG (PH) + PYTHIA8 (P8) DR and DS, POWHEG + HERWIG 7 (H7) DR, MadGraph-5_aMC@NLO (aMC) + PYTHIA8 DR, DR2, DS, and DS with a dynamic factor are also shown. The grey band represents the statistical uncertainty and the orange band the total uncertainty. In the lower panels, the ratio of the predictions to the data is shown. |
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Figure 9-a:
Normalised fiducial differential $ \mathrm{t}\mathrm{W} $ production cross section as functions of the $ p_{\mathrm{T}} $ of the leading lepton (upper left), $ p_\mathrm{z}(\mathrm{e}^\pm, \mu^\mp, j) $ (upper right), $ p_{\mathrm{T}} $ of the jet (middle left), $ m(\mathrm{e}^\pm, \mu^\mp, j) $ (middle right), $ \Delta\varphi(\mathrm{e}^\pm, \mu^\mp) $ (lower left), and $ m_{\mathrm{T}}(\mathrm{e}^\pm, \mu^\mp, j, {\vec p}_{\mathrm{T}}^{\kern1pt\text{miss}}) $ (lower right). The vertical bars on the points give the statistical uncertainty in the data, the horizontal bars show the bin width. Predictions from POWHEG (PH) + PYTHIA8 (P8) DR and DS, POWHEG + HERWIG 7 (H7) DR, MadGraph-5_aMC@NLO (aMC) + PYTHIA8 DR, DR2, DS, and DS with a dynamic factor are also shown. The grey band represents the statistical uncertainty and the orange band the total uncertainty. In the lower panels, the ratio of the predictions to the data is shown. |
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Figure 9-b:
Normalised fiducial differential $ \mathrm{t}\mathrm{W} $ production cross section as functions of the $ p_{\mathrm{T}} $ of the leading lepton (upper left), $ p_\mathrm{z}(\mathrm{e}^\pm, \mu^\mp, j) $ (upper right), $ p_{\mathrm{T}} $ of the jet (middle left), $ m(\mathrm{e}^\pm, \mu^\mp, j) $ (middle right), $ \Delta\varphi(\mathrm{e}^\pm, \mu^\mp) $ (lower left), and $ m_{\mathrm{T}}(\mathrm{e}^\pm, \mu^\mp, j, {\vec p}_{\mathrm{T}}^{\kern1pt\text{miss}}) $ (lower right). The vertical bars on the points give the statistical uncertainty in the data, the horizontal bars show the bin width. Predictions from POWHEG (PH) + PYTHIA8 (P8) DR and DS, POWHEG + HERWIG 7 (H7) DR, MadGraph-5_aMC@NLO (aMC) + PYTHIA8 DR, DR2, DS, and DS with a dynamic factor are also shown. The grey band represents the statistical uncertainty and the orange band the total uncertainty. In the lower panels, the ratio of the predictions to the data is shown. |
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Figure 9-c:
Normalised fiducial differential $ \mathrm{t}\mathrm{W} $ production cross section as functions of the $ p_{\mathrm{T}} $ of the leading lepton (upper left), $ p_\mathrm{z}(\mathrm{e}^\pm, \mu^\mp, j) $ (upper right), $ p_{\mathrm{T}} $ of the jet (middle left), $ m(\mathrm{e}^\pm, \mu^\mp, j) $ (middle right), $ \Delta\varphi(\mathrm{e}^\pm, \mu^\mp) $ (lower left), and $ m_{\mathrm{T}}(\mathrm{e}^\pm, \mu^\mp, j, {\vec p}_{\mathrm{T}}^{\kern1pt\text{miss}}) $ (lower right). The vertical bars on the points give the statistical uncertainty in the data, the horizontal bars show the bin width. Predictions from POWHEG (PH) + PYTHIA8 (P8) DR and DS, POWHEG + HERWIG 7 (H7) DR, MadGraph-5_aMC@NLO (aMC) + PYTHIA8 DR, DR2, DS, and DS with a dynamic factor are also shown. The grey band represents the statistical uncertainty and the orange band the total uncertainty. In the lower panels, the ratio of the predictions to the data is shown. |
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Figure 9-d:
Normalised fiducial differential $ \mathrm{t}\mathrm{W} $ production cross section as functions of the $ p_{\mathrm{T}} $ of the leading lepton (upper left), $ p_\mathrm{z}(\mathrm{e}^\pm, \mu^\mp, j) $ (upper right), $ p_{\mathrm{T}} $ of the jet (middle left), $ m(\mathrm{e}^\pm, \mu^\mp, j) $ (middle right), $ \Delta\varphi(\mathrm{e}^\pm, \mu^\mp) $ (lower left), and $ m_{\mathrm{T}}(\mathrm{e}^\pm, \mu^\mp, j, {\vec p}_{\mathrm{T}}^{\kern1pt\text{miss}}) $ (lower right). The vertical bars on the points give the statistical uncertainty in the data, the horizontal bars show the bin width. Predictions from POWHEG (PH) + PYTHIA8 (P8) DR and DS, POWHEG + HERWIG 7 (H7) DR, MadGraph-5_aMC@NLO (aMC) + PYTHIA8 DR, DR2, DS, and DS with a dynamic factor are also shown. The grey band represents the statistical uncertainty and the orange band the total uncertainty. In the lower panels, the ratio of the predictions to the data is shown. |
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Figure 9-e:
Normalised fiducial differential $ \mathrm{t}\mathrm{W} $ production cross section as functions of the $ p_{\mathrm{T}} $ of the leading lepton (upper left), $ p_\mathrm{z}(\mathrm{e}^\pm, \mu^\mp, j) $ (upper right), $ p_{\mathrm{T}} $ of the jet (middle left), $ m(\mathrm{e}^\pm, \mu^\mp, j) $ (middle right), $ \Delta\varphi(\mathrm{e}^\pm, \mu^\mp) $ (lower left), and $ m_{\mathrm{T}}(\mathrm{e}^\pm, \mu^\mp, j, {\vec p}_{\mathrm{T}}^{\kern1pt\text{miss}}) $ (lower right). The vertical bars on the points give the statistical uncertainty in the data, the horizontal bars show the bin width. Predictions from POWHEG (PH) + PYTHIA8 (P8) DR and DS, POWHEG + HERWIG 7 (H7) DR, MadGraph-5_aMC@NLO (aMC) + PYTHIA8 DR, DR2, DS, and DS with a dynamic factor are also shown. The grey band represents the statistical uncertainty and the orange band the total uncertainty. In the lower panels, the ratio of the predictions to the data is shown. |
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Figure 9-f:
Normalised fiducial differential $ \mathrm{t}\mathrm{W} $ production cross section as functions of the $ p_{\mathrm{T}} $ of the leading lepton (upper left), $ p_\mathrm{z}(\mathrm{e}^\pm, \mu^\mp, j) $ (upper right), $ p_{\mathrm{T}} $ of the jet (middle left), $ m(\mathrm{e}^\pm, \mu^\mp, j) $ (middle right), $ \Delta\varphi(\mathrm{e}^\pm, \mu^\mp) $ (lower left), and $ m_{\mathrm{T}}(\mathrm{e}^\pm, \mu^\mp, j, {\vec p}_{\mathrm{T}}^{\kern1pt\text{miss}}) $ (lower right). The vertical bars on the points give the statistical uncertainty in the data, the horizontal bars show the bin width. Predictions from POWHEG (PH) + PYTHIA8 (P8) DR and DS, POWHEG + HERWIG 7 (H7) DR, MadGraph-5_aMC@NLO (aMC) + PYTHIA8 DR, DR2, DS, and DS with a dynamic factor are also shown. The grey band represents the statistical uncertainty and the orange band the total uncertainty. In the lower panels, the ratio of the predictions to the data is shown. |
| Tables | |
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Table 1:
Selection requirements for particle-level objects. |
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Table 2:
Definition of the fiducial region. |
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Table 3:
The number of observed and MC predicted events after the fit in the 1j1b, 2j1b, and 2j2b regions. The statistical uncertainties in the data and the total uncertainties in the predictions are given. |
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Table 4:
The $ p $-values from the goodness-of-fit tests comparing the six differential cross section measurements with the predictions from POWHEG (PH) + PYTHIA8 (P8) DR and DS and POWHEG + HERWIG 7 (H7) DR. The complete covariance matrix from the results and the statistical uncertainties in the predictions are taken into account. |
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Table 5:
The $ p $-values from the goodness-of-fit tests comparing the six differential cross section measurements with the predictions from MadGraph-5_aMC@NLO (aMC) + PYTHIA8 DR, DR2, DS, and DS with a dynamic factor. The complete covariance matrix from the results and the statistical uncertainties in the predictions are taken into account. |
| Summary |
| Inclusive and normalised differential cross sections for the production of a top quark in association with a W boson are measured in proton-proton collision data at $ \sqrt{s}=$ 13.6 TeV. The selected data, corresponding to an integrated luminosity of 34.7 fb$^{-1}$, recorded by the CMS detector, contain events with an electron and a muon of opposite charge. For the inclusive measurement, the events have been categorised depending on the number of jets and jets originating from the fragmentation of bottom quarks. The signal is measured using a maximum likelihood fit to the distribution of random forest discriminants in two of the categories, and to the transverse momentum ($ p_{\mathrm{T}} $) distribution of the second-highest-$ p_{\mathrm{T}} $ jet in a third category. The measured inclusive cross section is 84.1 $ \pm $ 2.1 (stat) $^{+9.8}_{-10.2} $ (syst) $ \pm $ 3.3 (lumi) pb, with a total relative uncertainty of about 13%. This measurement is in agreement with the latest predictions and measurements. The differential cross section measurements are performed as a function of six kinematical observables of the events in the fiducial phase space corresponding to the selection criteria. The results have relative uncertainties in the range of 30-40%, depending on the measured observable. The uncertainties are overall statistically dominated. There is good agreement between the measurements and the predictions from the different event generators. The different approaches used to simulate $ \mathrm{t}\mathrm{W} $ events give similar values in all distributions, which points to small effects of $ \mathrm{t}\mathrm{W} $/ $ \mathrm{t} \overline{\mathrm{t}} $ interference on these distributions in the defined fiducial region. |
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