Measurement of differential $t\overline{t}$ production cross sections in the full kinematic range using $\mathrm{lepton}+\text{jets}$ events from proton-proton collisions at $\sqrt{s}=13\text{ }\text{ }\mathrm{TeV}$

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Measurement of differential $t \bar{t}$ production cross sections in the full kinematic range using $lepton + jets$ events from proton-proton collisions at $\sqrt{s} = 13 TeV$

A. Tumasyan et al. (CMS Collaboration)

Phys. Rev. D 104, 092013 – Published 30 November 2021

Abstract

Measurements of differential and double-differential cross sections of top-quark pair ( $t \bar{t}$ ) production are presented in the $lepton + jets$ channels with a single electron or muon and jets in the final state. The analysis combines for the first time signatures of top quarks with low transverse momentum $p_{T}$ , where the top-quark decay products can be identified as separated jets and isolated leptons, and with high $p_{T}$ , where the decay products are collimated and overlap. The measurements are based on proton-proton collision data at $\sqrt{s} = 13 TeV$ collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of $137 {fb}^{- 1}$ . The cross sections are presented at the parton and particle levels, where the latter minimizes extrapolations based on theoretical assumptions. Most of the measured differential cross sections are well described by standard model predictions with the exception of some double-differential distributions. The inclusive $t \bar{t}$ production cross section is measured to be $σ_{t \bar{t}} = 791 \pm 25 pb$ , which constitutes the most precise measurement in the $lepton + jets$ channel to date.

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Received 5 August 2021
Accepted 5 October 2021

DOI:https://doi.org/10.1103/PhysRevD.104.092013

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP³.

Physics Subject Headings (PhySH)

Particle production

Top quark

Hadron colliders

Particles & Fields

Authors & Affiliations

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Article Text

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References

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Issue

Vol. 104, Iss. 9 — 1 November 2021

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Images

Figure 1
Comparison between the $p_{T} (t_{h})$ distributions at the particle and parton levels, extracted from the powheg+pythia simulation. Left: the percentage of $p_{T}$ -bin migration between the particle and parton levels, shown using the color scale to the right of the plot. The bin boundaries are those shown in the lower panel. Each column is normalized such that the sum of its entries corresponds to the fraction of particle-level events in this bin at the parton level in the full phase space. Lower: fraction of parton-level top quarks in the same $p_{T}$ bin at the particle level (purity), fraction of particle-level top quarks in the same $p_{T}$ bin at the parton level (stability), ratio of the number of particle- to parton-level top quarks (bin efficiency), and the fraction of particle-level events that are not signal events at the parton level.
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Figure 2
Upper: Normalized two-dimensional mass distribution of the correctly reconstructed hadronically decaying $W$ bosons and the correctly reconstructed $t_{h}$ candidate. Lower: Normalized distributions of the reconstructed $m (t_{ℓ})$ for correctly (solid red curve) and incorrectly (dashed blue curve) selected $b_{ℓ}$ . The distributions are taken from the powheg+pythia $t \bar{t}$ simulation for the parton-level measurement.
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Figure 3
Distributions of the negative log-likelihood for the selected best permutation in the (upper) 2t and (lower) 1t1l categories. The comparisons of data (points) and predictions (colored histograms) are shown for the (left) parton- and (right) particle-level measurements. Events generated with powheg+pythia describe $t \bar{t}$ production. The contribution of multijet, DY, and $W$ -boson background events is extracted from the data (cf. Sec. 10). Combined systematic (cf. Sec. 13) and statistical uncertainties (hatched area) are shown for the total predicted yields. The vertical bars on the points show the statistical uncertainty. The ratio of the data to the sum of the predicted yields is provided in the lower portion of each panel.
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Figure 4
Distributions of the output discriminant $L_{NN}$ used in the boosted $t_{ℓ}$ identification for the low- $p_{T} (t_{ℓ})$ (upper) and high- $p_{T} (t_{ℓ})$ (lower) regions. The data (points) and predictions from simulation (colored histograms) are shown. The hatched area gives the combined statistical and systematic uncertainties in the prediction. The vertical bars on the points show the statistical uncertainty in the data. The ratio of the data to the sum of the individual predictions is displayed in the lower portion of each panel.
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Figure 5
The selection efficiency for background jets as a function of the signal selection efficiency in three $p_{T} (t_{h})$ ranges for 3Q (solid curves) and $2 Q + 3 Q$ (dashed curves) jets from simulation. An efficiency of 100% corresponds to the preselection of $| η | < 2.4$ and $m_{jet} > 120 GeV$ .
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Figure 6
Schematic overview of the categories and how they are used in the analysis.
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Figure 7
Comparisons of various reconstructed kinematic distributions between data (points) and predictions (colored histograms) obtained for the parton-level measurement. Contributions of the various reconstruction categories are obtained from the powheg+pythia $t \bar{t}$ simulation. The contributions of multijet, DY, and $W$ -boson background events in the 2t and 1t1l categories are extracted from the data (cf. Sec. 10). All other background contributions are taken from simulation. Combined systematic (cf. Sec. 13) and statistical uncertainties (hatched area) are shown for the total predicted yields. The data points are shown with statistical uncertainties. The ratio of the data to the sum of the predicted yields is provided in the lower portion of each panel.
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Figure 8
The $p_{T} (t_{h})$ (upper) and $p_{T} (t_{ℓ})$ (lower) distributions for the multijet and $DY / W$ -boson backgrounds from data (points) in the control region and from simulation (colored histograms) in the signal region for the 1t1l category. The red lines show the variations in the control region distribution when shifting the discriminant selection range up (solid lines) and down (dotted lines). The blue dashed line gives the sum of the multijet and $DY / W$ -boson predictions in the control region. The hatched band shows the statistical uncertainties in the prediction. The data points are shown with statistical uncertainties. The ratio of the data to the predicted yields is provided in the lower portion of each panel.
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Figure 9
The postfit $H_{NN}$ distributions in bins of $p_{T} (t_{h})$ (left) and $m (t \bar{t})$ (right) for the data (points) and simulation (colored histograms). The electron and muon events and all three years of data taking have been combined. The hatched area shows the total uncertainties from the fit. The vertical bars on the points represent the statistical uncertainty in the data. The ratio of the data to the sum of the fitted yields is provided in the lower portion of each panel.
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Figure 10
Distributions of $p_{T} (t_{h})$ (upper left), $m (t \bar{t})$ (upper right), $p_{T} (t \bar{t})$ (lower left), and $m (t \bar{t}) vs | y (t \bar{t}) |$ (lower right) after background subtraction. The points show the data, and the dashed lines indicate the predictions for the various event types. The ratio of the data to the predictions is provided in the lower portion of each panel. The vertical bars on the points give the statistical uncertainties, and the horizontal bars give the bin widths.
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Figure 11
Combined response matrices of all reconstruction categories for the measurements of $p_{T} (t_{h})$ at parton (upper left) and particle (lower left) levels from the powheg+pythia simulation. The purity (fraction of parton-/particle-level events that are reconstructed in the same bin at the detector level), stability (fraction of detector-level events that belong in the same bin at the parton/particle level), the efficiency per bin, and the fraction of $t \bar{t}$ background for the corresponding parton and particle levels are shown in the right plots.
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Figure 12
The $p$ values of the $χ^{2}$ fits for the listed variables are shown for the parton- (upper) and particle-level (lower) measurements.
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Figure 13
The individual sources of systematic uncertainties in the various parton (left) and particle (right) measurements, and their relative contributions to the overall uncertainty. Sources with a maximum uncertainty below 1.5% are combined in the category “Other.”
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Figure 14
The $Z$ scores from the corresponding $χ^{2}$ tests comparing the measured differential cross sections for the shown variables at the parton (upper) and particle (lower) levels to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), the multiparton simulation mg5_amc@nlo(MG)+pythia FxFx, and the NNLO QCD calculations obtained with matrix. The $Z$ scores are truncated at an upper limit of 6. The uncertainties in the measurements and the predictions are taken into account in the $χ^{2}$ calculation.
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Figure 15
Differential cross sections at the parton level as functions of $p_{T} (t_{h})$ , $p_{T} (t_{ℓ})$ , $p_{T} (t_{high})$ , $p_{T} (t_{low})$ , and $S_{T}$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg combined with pythia (P8) or herwig (H7), the multiparton simulation mg5_amc@nlo (MG)+pythia FxFx, and the NNLO QCD calculations obtained with matrix. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 16
Differential cross sections at the particle level as functions of $p_{T} (t_{h})$ , $p_{T} (t_{ℓ})$ , $p_{T} (t_{high})$ , $p_{T} (t_{low})$ , and $S_{T}$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 17
Differential cross sections at the parton level as functions of $| y (t_{h}) |$ , $| y (t_{ℓ}) |$ , and the differences $Δ | y_{t / \bar{t}} |$ and $| Δ y_{t / \bar{t}} |$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg combined with pythia (P8) or herwig (H7), the multiparton simulation mg5_amc@nlo (MG)+pythia FxFx, and the NNLO QCD calculations obtained with matrix. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 18
Differential cross sections at the particle level as functions of $| y (t_{h}) |$ , $| y (t_{ℓ}) |$ , and the differences $Δ | y_{t / \bar{t}} |$ and $| Δ y_{t / \bar{t}} |$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 19
Differential cross sections at the parton level as functions of kinematic variables of the $t \bar{t}$ system. The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg combined with pythia (P8) or herwig (H7), the multiparton simulation mg5_amc@nlo (MG)+pythia FxFx, and the NNLO QCD calculations obtained with matrix. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 20
Differential cross sections at the particle level as functions of kinematic variables of the $t \bar{t}$ system. The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 21
Double-differential cross section at the parton level as a function of $p_{T} (t_{h}) vs | y (t_{h}) |$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg combined with pythia (P8) or herwig (H7), the multiparton simulation mg5_amc@nlo (MG)+pythia FxFx, and the NNLO QCD calculations obtained with matrix. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 22
Double-differential cross section at the particle level as a function of $p_{T} (t_{h}) vs | y (t_{h}) |$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 23
Double-differential cross section at the parton level as a function of $m (t \bar{t}) vs | y (t \bar{t}) |$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg combined with pythia (P8) or herwig (H7), the multiparton simulation mg5_amc@nlo (MG)+pythia FxFx, and the NNLO QCD calculations obtained with matrix. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 24
Double-differential cross section at the particle level as a function of $m (t \bar{t}) vs | y (t \bar{t}) |$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 25
Double-differential cross section at the parton level as a function of $m (t \bar{t}) vs \cos (θ^{*})$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg combined with pythia (P8) or herwig (H7), the multiparton simulation mg5_amc@nlo (MG)+pythia FxFx, and the NNLO QCD calculations obtained with matrix. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 26
Double-differential cross section at the particle level as a function of $m (t \bar{t}) vs \cos (θ^{*})$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 27
Double-differential cross section at the parton level as a function of $m (t \bar{t}) vs p_{T} (t_{h})$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg combined with pythia (P8) or herwig (H7), the multiparton simulation mg5_amc@nlo (MG)+pythia FxFx, and the NNLO QCD calculations obtained with matrix. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 28
Double-differential cross section at the particle level as a function of $m (t \bar{t}) vs p_{T} (t_{h})$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 29
Double-differential cross section at the parton level as a function of $p_{T} (t \bar{t}) vs p_{T} (t_{h})$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg combined with pythia (P8) or herwig (H7), the multiparton simulation mg5_amc@nlo (MG)+pythia FxFx, and the NNLO QCD calculations obtained with matrix. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 30
Double-differential cross section at the particle level as a function of $p_{T} (t \bar{t}) vs p_{T} (t_{h})$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 31
Double-differential cross section at the parton level as a function of $| Δ y_{t / \bar{t}} | vs m (t \bar{t})$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg combined with pythia (P8) or herwig (H7), the multiparton simulation mg5_amc@nlo (MG)+pythia FxFx, and the NNLO QCD calculations obtained with matrix. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 32
Double-differential cross section at the particle level as a function of $| Δ y_{t / \bar{t}} | vs m (t \bar{t})$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 33
Double-differential cross section at the parton level as a function of $m (t \bar{t}) vs Δ | y_{t / \bar{t}} |$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg combined with pythia (P8) or herwig (H7), the multiparton simulation mg5_amc@nlo (MG)+pythia FxFx, and the NNLO QCD calculations obtained with matrix. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 34
Double-differential cross section at the particle level as a function of $m (t \bar{t}) vs Δ | y_{t / \bar{t}} |$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 35
Double-differential cross section at the parton level as a function of $| y (t) | vs | y (\bar{t}) |$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg combined with pythia (P8) or herwig (H7), the multiparton simulation mg5_amc@nlo (MG)+pythia FxFx, and the NNLO QCD calculations obtained with matrix. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel. Lower right: ratio of $| y (\bar{t}) | / | y (t) |$ .
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Figure 36
Double-differential cross section at the particle level as a function of $| y (t) | vs | y (\bar{t}) |$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel. Lower right: ratio of $| y (\bar{t}) | / | y (t) |$ .
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Figure 37
Measurements of the $t \bar{t}$ production cross sections $σ_{e / μ + jets}$ , with their total uncertainty obtained as the sum of the cross sections in all bins of a distribution as a function of the kinematic variable used in the determination. The results are compared to the top++ and the matrix predictions with their corresponding uncertainties.
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Figure 38
Measurements of the $t \bar{t}$ production cross sections $σ_{particle}$ at the particle level, and their total uncertainties as a function of the kinematic variable used in the determination. The results are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo(MG)+pythia.
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Figure 39
Differential cross sections at the particle level as functions of $p_{T} (ℓ)$ , jet multiplicity, $H_{T}$ , and $m_{evt}$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 40
Differential cross section at the particle level as a function of $p_{T} (t_{h})$ in bins of jet multiplicity. The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 41
Differential cross section at the particle level as a function of $m (t \bar{t})$ in bins of jet multiplicity. The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 42
Differential cross section at the particle level as a function of $p_{T} (t \bar{t})$ in bins of jet multiplicity. The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 43
Normalized differential cross sections at the parton level as functions of $p_{T} (t_{h})$ , $p_{T} (t_{ℓ})$ , $p_{T} (t_{high})$ , $p_{T} (t_{low})$ , and $S_{T}$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg combined with pythia (P8) or herwig (H7), the multiparton simulation mg5_amc@nlo (MG)+pythia FxFx, and the NNLO QCD calculations obtained with matrix. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 44
Normalized differential cross sections at the particle level as functions of $p_{T} (t_{h})$ , $p_{T} (t_{ℓ})$ , $p_{T} (t_{high})$ , $p_{T} (t_{low})$ , and $S_{T}$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 45
Normalized differential cross sections at the parton level as functions of $| y (t_{h}) |$ , $| y (t_{ℓ}) |$ , and the differences $Δ | y_{t / \bar{t}} |$ and $| Δ y_{t / \bar{t}} |$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg combined with pythia (P8) or herwig (H7), the multiparton simulation mg5_amc@nlo (MG)+pythia FxFx, and the NNLO QCD calculations obtained with matrix. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 46
Normalized differential cross sections at the particle level as functions of $| y (t_{h}) |$ , $| y (t_{ℓ}) |$ , and the differences $Δ | y_{t / \bar{t}} |$ and $| Δ y_{t / \bar{t}} |$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 47
Normalized differential cross sections at the parton level as functions of kinematic variables of the $t \bar{t}$ system. The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg combined with pythia (P8) or herwig (H7), the multiparton simulation mg5_amc@nlo (MG)+pythia FxFx, and the NNLO QCD calculations obtained with matrix. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 48
Normalized differential cross sections at the particle level as functions of kinematic variables of the $t \bar{t}$ system. The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 49
Normalized double-differential cross section at the parton level as a function of $p_{T} (t_{h}) vs | y (t_{h}) |$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg combined with pythia (P8) or herwig (H7), the multiparton simulation mg5_amc@nlo (MG)+pythia FxFx, and the NNLO QCD calculations obtained with matrix. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 50
Normalized double-differential cross section at the particle level as a function of $p_{T} (t_{h}) vs | y (t_{h}) |$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 51
Normalized double-differential cross section at the parton level as a function of $m (t \bar{t}) vs | y (t \bar{t}) |$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg combined with pythia (P8) or herwig (H7), the multiparton simulation mg5_amc@nlo (MG)+pythia FxFx, and the NNLO QCD calculations obtained with matrix. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 52
Normalized double-differential cross section at the particle level as a function of $m (t \bar{t}) vs | y (t \bar{t}) |$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 53
Normalized double-differential cross section at the parton level as a function of $m (t \bar{t}) vs \cos (θ^{*})$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg combined with pythia (P8) or herwig (H7), the multiparton simulation mg5_amc@nlo (MG)+pythia FxFx, and the NNLO QCD calculations obtained with matrix. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 54
Normalized double-differential cross section at the particle level as a function of $m (t \bar{t}) vs \cos (θ^{*})$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 55
Normalized double-differential cross section at the parton level as a function of $m (t \bar{t}) vs p_{T} (t_{h})$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg combined with pythia (P8) or herwig (H7), the multiparton simulation mg5_amc@nlo (MG)+pythia FxFx, and the NNLO QCD calculations obtained with matrix. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 56
Normalized double-differential cross section at the particle level as a function of $m (t \bar{t}) vs p_{T} (t_{h})$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 57
Normalized double-differential cross section at the parton level as a function of $p_{T} (t \bar{t}) vs p_{T} (t_{h})$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg combined with pythia (P8) or herwig (H7), the multiparton simulation mg5_amc@nlo (MG)+pythia FxFx, and the NNLO QCD calculations obtained with matrix. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 58
Normalized double-differential cross section at the particle level as a function of $p_{T} (t \bar{t}) vs p_{T} (t_{h})$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 59
Normalized double-differential cross section at the parton level as a function of $| Δ y_{t / \bar{t}} | vs m (t \bar{t})$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg combined with pythia (P8) or herwig (H7), the multiparton simulation mg5_amc@nlo (MG)+pythia FxFx, and the NNLO QCD calculations obtained with matrix. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 60
Normalized double-differential cross section at the particle level as a function of $| Δ y_{t / \bar{t}} | vs m (t \bar{t})$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 61
Normalized double-differential cross section at the parton level as a function of $m (t \bar{t}) vs Δ | y_{t / \bar{t}} |$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg combined with pythia (P8) or herwig (H7), the multiparton simulation mg5_amc@nlo (MG)+pythia FxFx, and the NNLO QCD calculations obtained with matrix. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 62
Normalized double-differential cross section at the particle level as a function of $m (t \bar{t}) vs Δ | y_{t / \bar{t}} |$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 63
Normalized double-differential cross section at the parton level as a function of $| y (t) | vs | y (\bar{t}) |$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg combined with pythia (P8) or herwig (H7), the multiparton simulation mg5_amc@nlo (MG)+pythia FxFx, and the NNLO QCD calculations obtained with matrix. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 64
Normalized double-differential cross section at the particle level as a function of $| y (t) | vs | y (\bar{t}) |$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 65
Normalized differential cross sections at the particle level as functions of $p_{T} (ℓ)$ , jet multiplicity, $H_{T}$ , and $m_{evt}$ . The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 66
Normalized differential cross section at the particle level as a function of $p_{T} (t_{h})$ in bins of jet multiplicity. The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 67
Normalized differential cross section at the particle level as a function of $m (t \bar{t})$ in bins of jet multiplicity. The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 68
Normalized differential cross section at the particle level as a function of $p_{T} (t \bar{t})$ in bins of jet multiplicity. The data are shown as points with gray (yellow) bands indicating the statistical (statistical and systematic) uncertainties. The cross sections are compared to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), and the multiparton simulation mg5_amc@nlo (MG)+pythia. The ratios of the various predictions to the measured cross sections are shown in the lower portion of each panel.
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Figure 69
Results of $χ^{2}$ tests in $Z$ scores comparing the measured normalized cross sections at the parton (upper) and particle (lower) levels to the predictions of powheg+pythia (P8) for the CP5 and CUETP8M2T4 (T4) tunes, powheg+herwig (H7), the multiparton simulation mg5_amc@nlo (MG)+pythia FxFx, and the NNLO QCD calculations obtained with matrix. The $Z$ scores are truncated at an upper limit of 6. The uncertainties in the measurements and the predictions are taken into account for the calculation of the $χ^{2}$ .
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Physical Review D

covering particles, fields, gravitation, and cosmology

Measurement of differential $t \bar{t}$ production cross sections in the full kinematic range using $lepton + jets$ events from proton-proton collisions at $\sqrt{s} = 13 TeV$

A. Tumasyan et al. (CMS Collaboration)

Phys. Rev. D 104, 092013 – Published 30 November 2021

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Physical Review D

covering particles, fields, gravitation, and cosmology

Measurement of differential tt¯ production cross sections in the full kinematic range using lepton+jets events from proton-proton collisions at s=13 TeV

A. Tumasyan et al. (CMS Collaboration)

Phys. Rev. D 104, 092013 – Published 30 November 2021

Abstract

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Measurement of differential $t \bar{t}$ production cross sections in the full kinematic range using $lepton + jets$ events from proton-proton collisions at $\sqrt{s} = 13 TeV$