CMS-TOP-22-013 ; CERN-EP-2023-090 | ||
Observation of four top quark production in proton-proton collisions at $ \sqrt{s}= $ 13 TeV | ||
CMS Collaboration | ||
22 May 2023 | ||
Phys. Lett. B 847 (2023) 138290 | ||
Abstract: The observation of the production of four top quarks in proton-proton collisions is reported, based on a data sample collected by the CMS experiment at a center-of-mass energy of 13 TeV in 2016--2018 at the CERN LHC and corresponding to an integrated luminosity of 138 fb$ ^{-1} $. Events with two same-sign, three, or four charged leptons (electrons and muons) and additional jets are analyzed. Compared to previous results in these channels, updated identification techniques for charged leptons and jets originating from the hadronization of b quarks, as well as a revised multivariate analysis strategy to distinguish the signal process from the main backgrounds, lead to an improved expected signal significance of 4.9 standard deviations above the background-only hypothesis. Four top quark production is observed with a significance of 5.6 standard deviations, and its cross section is measured to be 17.7 $ ^{+3.7}_{-3.5} $ (stat) $ ^{+2.3}_{-1.9} $ (syst) fb, in agreement with the available standard model predictions. | ||
Links: e-print arXiv:2305.13439 [hep-ex] (PDF) ; CDS record ; inSPIRE record ; HepData record ; Physics Briefing ; CADI line (restricted) ; |
Figures & Tables | Summary | Additional Figures & Tables | References | CMS Publications |
---|
Figures | |
png pdf |
Figure 1:
Examples of Feynman diagrams that provide important contributions to $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ production. The first diagram (left) involves only the strong interaction, while the other two involve both strong and electroweak interactions with the exchange of a Z boson or virtual photon (middle), or a Higgs boson (right). |
png pdf |
Figure 1-a:
Example of Feynman diagram that provides important contribution to $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ production. The diagram involves only the strong interaction. |
png pdf |
Figure 1-b:
Example of Feynman diagram that provides important contribution to $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ production. The diagram involves both strong and electroweak interactions with the exchange of a Z boson or virtual photon. |
png pdf |
Figure 1-c:
Example of Feynman diagram that provides important contribution to $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ production. The diagram involves both strong and electroweak interactions with the exchange of a Higgs boson. |
png pdf |
Figure 2:
Efficiency of selecting prompt leptons as a function of the misidentification probability for nonprompt leptons evaluated in simulated $ \mathrm{t} \bar{\mathrm{t}} $ events for the electron (red solid line) and muon (blue dashed line) ID BDT, shown for leptons with 10 $ < p_{\mathrm{T}} < $ 25 GeV (left) and $ p_{\mathrm{T}} > $ 25 GeV (right). Indicated with filled markers are the efficiencies for the ID criteria applied in this measurement and with empty markers those for the ID criteria applied in Ref. [41], where red circles and blue squares are used for electron and muon criteria, respectively. |
png pdf |
Figure 2-a:
Efficiency of selecting prompt leptons as a function of the misidentification probability for nonprompt leptons evaluated in simulated $ \mathrm{t} \bar{\mathrm{t}} $ events for the electron (red solid line) and muon (blue dashed line) ID BDT, shown for leptons with 10 $ < p_{\mathrm{T}} < $ 25 GeV. Indicated with filled markers are the efficiencies for the ID criteria applied in this measurement and with empty markers those for the ID criteria applied in Ref. [41], where red circles and blue squares are used for electron and muon criteria, respectively. |
png pdf |
Figure 2-b:
Efficiency of selecting prompt leptons as a function of the misidentification probability for nonprompt leptons evaluated in simulated $ \mathrm{t} \bar{\mathrm{t}} $ events for the electron (red solid line) and muon (blue dashed line) ID BDT, shown for leptons with $ p_{\mathrm{T}} > $ 25 GeV. Indicated with filled markers are the efficiencies for the ID criteria applied in this measurement and with empty markers those for the ID criteria applied in Ref. [41], where red circles and blue squares are used for electron and muon criteria, respectively. |
png pdf |
Figure 3:
Schematic representation of the event selection and categorization. |
png pdf |
Figure 4:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ {\mathrm{t}\bar{\mathrm{t}}} \mathrm{}$X in the $ {\mathrm{t}\bar{\mathrm{t}}} \mathrm{}$X classes of SR-2$\ell $ in the $ \mu\mu $ category (left), of SR-3$\ell $ (middle), and of SR-4$\ell $ (right). The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with their best fit normalizations from the simultaneous fit to the data (``postfit''). |
png pdf |
Figure 4-a:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ {\mathrm{t}\bar{\mathrm{t}}} \mathrm{}$X in the $ {\mathrm{t}\bar{\mathrm{t}}} \mathrm{}$X classes of SR-2$\ell $ in the $ \mu\mu $ category. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with their best fit normalizations from the simultaneous fit to the data (``postfit''). |
png pdf |
Figure 4-b:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ {\mathrm{t}\bar{\mathrm{t}}} \mathrm{}$X in the $ {\mathrm{t}\bar{\mathrm{t}}} \mathrm{}$X classes of SR-3$\ell $. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with their best fit normalizations from the simultaneous fit to the data (``postfit''). |
png pdf |
Figure 4-c:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ {\mathrm{t}\bar{\mathrm{t}}} \mathrm{}$X in the $ {\mathrm{t}\bar{\mathrm{t}}} \mathrm{}$X classes of SR-4$\ell $. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with their best fit normalizations from the simultaneous fit to the data (``postfit''). |
png pdf |
Figure 5:
Comparison of the number of observed (points) and predicted (colored histograms) events in the number of jets distribution in CR-3$\ell$-Z (left), and in the number of b jets distribution in CR-3$\ell$-Z (middle) and CR-4$\ell$-Z (right). The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with their best fit normalizations from the simultaneous fit to the data (``postfit''). |
png pdf |
Figure 5-a:
Comparison of the number of observed (points) and predicted (colored histograms) events in the number of jets distribution in CR-3$\ell$-Z. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with their best fit normalizations from the simultaneous fit to the data (``postfit''). |
png pdf |
Figure 5-b:
Comparison of the number of observed (points) and predicted (colored histograms) events in the number of b jets distribution in CR-3$\ell$-Z. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with their best fit normalizations from the simultaneous fit to the data (``postfit''). |
png pdf |
Figure 5-c:
Comparison of the number of observed (points) and predicted (colored histograms) events in the number of b jets distribution in CR-4$\ell$-Z. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with their best fit normalizations from the simultaneous fit to the data (``postfit''). |
png pdf |
Figure 6:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ \mathrm{t} \bar{\mathrm{t}} $ in the combined CR-2$\ell$-23j1b and CR-2$\ell$-45j2b (left), in the event yields with negative and positive sum of lepton charges in CR-3$\ell$-2j1b (middle), and in the number of jets distribution in the $ \mathrm{t} \bar{\mathrm{t}} $ class of the combined SR-2$\ell $ and SR-3$\ell $ (right). The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with their best fit normalizations from the simultaneous fit to the data (``postfit''). |
png pdf |
Figure 6-a:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ \mathrm{t} \bar{\mathrm{t}} $ in the combined CR-2$\ell$-23j1b and CR-2$\ell$-45j2b. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with their best fit normalizations from the simultaneous fit to the data (``postfit''). |
png pdf |
Figure 6-b:
Comparison of the number of observed (points) and predicted (colored histograms) events in the event yields with negative and positive sum of lepton charges in CR-3$\ell$-2j1b. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with their best fit normalizations from the simultaneous fit to the data (``postfit''). |
png pdf |
Figure 6-c:
Comparison of the number of observed (points) and predicted (colored histograms) events in the number of jets distribution in the $ \mathrm{t} \bar{\mathrm{t}} $ class of the combined SR-2$\ell $ and SR-3$\ell $. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with their best fit normalizations from the simultaneous fit to the data (``postfit''). |
png pdf |
Figure 7:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ in the $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ classes of SR-2$\ell $, shown for the $ \mathrm{e}\mathrm{e} $ (upper left), $ \mathrm{e}\mu $ (upper middle), and $ \mu\mu $ (upper right) categories, of SR-3$\ell $ (lower left) and of SR-4$\ell $ (lower middle). Additionally, the comparison is shown for all SRs combined as a function of $ \log_{10}(\mathrm{S}/\mathrm{B}) $ (lower right), where S and B are evaluated for each bin of the fitted distributions as the predicted signal and background yields before the fit to data. Bins with $ \log_{10}(\mathrm{S}/\mathrm{B}) < - $1 are not included, and bins with $ \log_{10}(\mathrm{S}/\mathrm{B}) > $ 0.5 are included in the last bin. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with their best fit normalizations from the simultaneous fit to the data (``postfit''). |
png pdf |
Figure 7-a:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ in the $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ class of SR-2$\ell $, shown for the $ \mathrm{e}\mathrm{e} $ category. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with their best fit normalizations from the simultaneous fit to the data (``postfit''). |
png pdf |
Figure 7-b:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ in the $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ class of SR-2$\ell $, shown for the $ \mathrm{e}\mu $ category. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with their best fit normalizations from the simultaneous fit to the data (``postfit''). |
png pdf |
Figure 7-c:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ in the $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ class of SR-2$\ell $, shown for the $ \mu\mu $ category. |
png pdf |
Figure 7-d:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ in the $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ class of SR-3$\ell $. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with their best fit normalizations from the simultaneous fit to the data (``postfit''). |
png pdf |
Figure 7-e:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ in the $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ class of SR-4$\ell $. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with their best fit normalizations from the simultaneous fit to the data (``postfit''). |
png pdf |
Figure 7-f:
Comparison for all SRs combined as a function of $ \log_{10}(\mathrm{S}/\mathrm{B}) $, where S and B are evaluated for each bin of the fitted distributions as the predicted signal and background yields before the fit to data. Bins with $ \log_{10}(\mathrm{S}/\mathrm{B}) < - $1 are not included, and bins with $ \log_{10}(\mathrm{S}/\mathrm{B}) > $ 0.5 are included in the last bin. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with their best fit normalizations from the simultaneous fit to the data (``postfit''). |
png pdf |
Figure 8:
Comparison of fit results in the channels individually and in their combination. The left panel shows the values of the measured cross section relative to the SM prediction from Ref. [6], where the displayed uncertainty does not include the uncertainty in the SM prediction. The right panel shows the expected and observed significance, with the printed values rounded to the first decimal. |
png pdf |
Figure 9:
For the nuisance parameters listed in the left column, the pulls $ (\widehat{\theta}-\theta_0)/\Delta\theta $ (middle column) and impacts $ \Delta\widehat{r} $ (right column) are displayed. The 20 nuisance parameters with the largest impacts in the fit used to determine the $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ cross section are shown. The impact $ \Delta\widehat{r} $ is obtained from varying the nuisance parameter $ \theta $ by $ \pm $ 1 SD and evaluating the induced shift in the $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ signal strength $ r $. The pull $ (\widehat{\theta}-\theta_0)/\Delta\theta $ is calculated from the values $ \widehat{\theta} $ and $ \theta_0 $ after and before the fit of $ \theta $, respectively, and from its uncertainty $ \Delta\theta $ before the fit. The label ``corr.'' and the per-year labels indicate nuisance parameters associated with the correlated and uncorrelated parts of a systematic uncertainty, respectively. The nuisance parameters labeled ``MC stat.''\ refer to the per-bin statistical uncertainties in the predicted yields. The uncertainty associated with additional jets in $ {\mathrm{t}\bar{\mathrm{t}}} \mathrm{W} $ production corresponds to a one-sided variation of the nominal template before the fit, and thus a one-sided impact after the fit is expected. |
png pdf |
Figure A1:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ {\mathrm{t}\bar{\mathrm{t}}} \mathrm{}$X in the $ {\mathrm{t}\bar{\mathrm{t}}} \mathrm{}$X classes of SR-2$\ell $ in the $ \mu\mu $ category (left), of SR-3$\ell $ (middle), and of SR-4$\ell $ (right). The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data (``prefit''). |
png pdf |
Figure A1-a:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ {\mathrm{t}\bar{\mathrm{t}}} \mathrm{}$X in the $ {\mathrm{t}\bar{\mathrm{t}}} \mathrm{}$X classes of SR-2$\ell $ in the $ \mu\mu $ category. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data (``prefit''). |
png pdf |
Figure A1-b:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ {\mathrm{t}\bar{\mathrm{t}}} \mathrm{}$X in the $ {\mathrm{t}\bar{\mathrm{t}}} \mathrm{}$X classes of SR-3$\ell $. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data (``prefit''). |
png pdf |
Figure A1-c:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ {\mathrm{t}\bar{\mathrm{t}}} \mathrm{}$X in the $ {\mathrm{t}\bar{\mathrm{t}}} \mathrm{}$X classes of SR-4$\ell $. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data (``prefit''). |
png pdf |
Figure A2:
Comparison of the number of observed (points) and predicted (colored histograms) events in the number of jets distribution in CR-3$\ell$-Z (left), and in the number of b jets distribution in CR-3$\ell$-Z (middle) and CR-4$\ell$-Z (right). The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data (``prefit''). |
png pdf |
Figure A2-a:
Comparison of the number of observed (points) and predicted (colored histograms) events in the number of jets distribution in CR-3$\ell$-Z. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data (``prefit''). |
png pdf |
Figure A2-b:
Comparison of the number of observed (points) and predicted (colored histograms) events in the number of b jets distribution in CR-3$\ell$-Z. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data (``prefit''). |
png pdf |
Figure A2-c:
Comparison of the number of observed (points) and predicted (colored histograms) events in the number of b jets distribution in CR-4$\ell$-Z. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data (``prefit''). |
png pdf |
Figure A3:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ \mathrm{t} \bar{\mathrm{t}} $ in the combined CR-2$\ell$-23j1b and CR-2$\ell$-45j2b (left), in the event yields with negative and positive sum of lepton charges in CR-3$\ell$-2j1b (middle), and in the number of jets distribution in the $ \mathrm{t} \bar{\mathrm{t}} $ class of the combined SR-2$\ell $ and SR-3$\ell $ (right). The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data (``prefit''). |
png pdf |
Figure A3-a:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ \mathrm{t} \bar{\mathrm{t}} $ in the combined CR-2$\ell$-23j1b and CR-2$\ell$-45j2b. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data (``prefit''). |
png pdf |
Figure A3-b:
Comparison of the number of observed (points) and predicted (colored histograms) events in the event yields with negative and positive sum of lepton charges in CR-3$\ell$-2j1b. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data (``prefit''). |
png pdf |
Figure A3-c:
Comparison of the number of observed (points) and predicted (colored histograms) events in the number of jets distribution in the $ \mathrm{t} \bar{\mathrm{t}} $ class of the combined SR-2$\ell $ and SR-3$\ell $. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data (``prefit''). |
png pdf |
Figure A4:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ in the $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ classes of SR-2$\ell $, shown for the $ \mathrm{e}\mathrm{e} $ (upper left), $ \mathrm{e}\mu $ (upper middle), and $ \mu\mu $ (upper right) categories, of SR-3$\ell $ (lower left) and of SR-4$\ell $ (lower right). The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data (``prefit''). |
png pdf |
Figure A4-a:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ in the $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ classes of SR-2$\ell $, shown for the $ \mathrm{e}\mathrm{e} $ category. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data (``prefit''). |
png pdf |
Figure A4-b:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ in the $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ classes of SR-2$\ell $, shown for the $ \mathrm{e}\mu $ category. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data (``prefit''). |
png pdf |
Figure A4-c:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ in the $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ classes of SR-2$\ell $, shown for the $ \mu\mu $ category. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data (``prefit''). |
png pdf |
Figure A4-d:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ in the $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ classes of SR-3$\ell $. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data (``prefit''). |
png pdf |
Figure A4-e:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ in the $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ classes of SR-4$\ell $. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data (``prefit''). |
Tables | |
png pdf |
Table 1:
List of the input variables to the event multiclassification BDTs. The last two columns indicate the importance rank of the observables in the 2$ \ell $ and 3$ \ell $+4$ \ell $ BDT trainings, respectively, and a dash indicates that the observable is not used in that training. The $ m_{\mathrm{T2}} $ variable, defined in Refs. [96,97], is constructed from $ {\vec p}_{\mathrm{T}}^{\,\text{miss}} $ and two four-momenta of the particles or particle systems specified in the table. |
png pdf |
Table 2:
Number of predicted and observed events in the SR-2$\ell $ and SR-3$\ell {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ classes, both before the fit to the data (``prefit'') and with their best fit normalizations (``postfit''). The uncertainties in the predicted number of events include both the statistical and systematic components. The uncertainties in the total number of predicted background and background plus signal events are also given. A dash indicates that the corresponding background does not contribute. |
Summary |
A measurement of the production of four top quarks ($ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $) in proton-proton collisions at $ \sqrt{s}= $ 13 TeV has been presented, using events with two same-sign, three, and four charged leptons (electrons and muons) and additional jets from a data set corresponding to an integrated luminosity of 138 fb$ ^{-1} $ recorded with the CMS detector at the LHC. Multivariate discriminants are employed in the identification of prompt leptons and jets originating from the decay of b hadrons, and to distinguish between selected events from the $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ signal and the main background contributions. A profile likelihood fit is performed to the data in signal and control regions for the extraction of the $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ cross section. The improvements in object identification and analysis strategy bring the sensitivity of the analysis to the observation level, with an observed (expected) significance of the $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ signal above the background-only hypothesis of 5.6 (4.9) standard deviations. The signal cross section is measured to be $ \sigma({\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} )= $ 17.7 $^{+3.7}_{-3.5} $ (stat) $ ^{+2.3}_{-1.9} $ (syst) fb, in agreement with the available standard model predictions. This result marks a significant milestone in the top quark physics program of the LHC. |
Additional Figures | |
png pdf |
Additional Figure 1:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ \mathrm{t\bar{t}}$X in the $ \mathrm{t\bar{t}}$X class of SR-2$\ell$ in the ee category. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with their best fit normalizations from the simultaneous fit to the data ("postfit"). |
png pdf |
Additional Figure 2:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ \mathrm{t\bar{t}}$X in the $ \mathrm{t\bar{t}}$X class of SR-2$\ell$ in the e$ \mu $ category. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with their best fit normalizations from the simultaneous fit to the data ("postfit"). |
png pdf |
Additional Figure 3:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ \mathrm{t\bar{t}} $ in the $ \mathrm{t\bar{t}} $ class of SR-2$\ell$. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with their best fit normalizations from the simultaneous fit to the data ("postfit"). |
png pdf |
Additional Figure 4:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ \mathrm{t\bar{t}} $ in the $ \mathrm{t\bar{t}} $ class of SR-3$\ell $. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with their best fit normalizations from the simultaneous fit to the data ("postfit"). |
png pdf |
Additional Figure 5:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ \mathrm{t\bar{t}} $ in the CR-2$\ell$-45j2b. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with their best fit normalizations from the simultaneous fit to the data ("postfit"). |
png pdf |
Additional Figure 6:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ \mathrm{t\bar{t}} $ in the CR-2$\ell$-23j1b. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with their best fit normalizations from the simultaneous fit to the data ("postfit"). |
png pdf |
Additional Figure 7:
Comparison of the number of observed (points) and predicted (colored histograms) events in the number of jets distribution in CR-4$\ell$-Z. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with their best fit normalizations from the simultaneous fit to the data ("postfit"). |
png pdf |
Additional Figure 8:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ \mathrm{t\bar{t}}$X in the $ \mathrm{t\bar{t}}$X class of SR-2$\ell$ in the ee category. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data ("prefit"). |
png pdf |
Additional Figure 9:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ \mathrm{t\bar{t}}$X in the $ \mathrm{t\bar{t}}$X class of SR-2$\ell$ in the e$ \mu $ category. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data ("prefit"). |
png pdf |
Additional Figure 10:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ \mathrm{t\bar{t}} $ in the $ \mathrm{t\bar{t}} $ class of SR-2$\ell$. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data ("prefit"). |
png pdf |
Additional Figure 11:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ \mathrm{t\bar{t}} $ in the $ \mathrm{t\bar{t}} $ class of SR-3$\ell $. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data ("prefit"). |
png pdf |
Additional Figure 12:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ \mathrm{t\bar{t}} $ in the CR-2$\ell$-45j2b. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data ("prefit"). |
png pdf |
Additional Figure 13:
Comparison of the number of observed (points) and predicted (colored histograms) events in the BDT score $ \mathrm{t\bar{t}} $ in the CR-2$\ell$-23j1b. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data ("prefit"). |
png pdf |
Additional Figure 14:
Comparison of the number of observed (points) and predicted (colored histograms) events in the number of jets distribution in CR-4$\ell$-Z. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data ("prefit"). |
png pdf |
Additional Figure 15:
Comparison of the number of observed (points) and predicted (colored histograms) events in the $ H_{\mathrm{T}} $ distribution in CR-3$\ell$-Z. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with the best fit normalizations from the simultaneous fit of the BDT score distributions to the data ("postfit"). The last bin includes the overflow contribution. |
png pdf |
Additional Figure 16:
Comparison of the number of observed (points) and predicted (colored histograms) events in the number of medium b jets distribution in CR-3$\ell$-Z. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with the best fit normalizations from the simultaneous fit of the BDT score distributions to the data ("postfit"). The last bin includes the overflow contribution. |
png pdf |
Additional Figure 17:
Comparison of the number of observed (points) and predicted (colored histograms) events in the $ H_{\mathrm{T}} $ distribution in the $ \mathrm{t\bar{t}t\bar{t}} $ class of the combined SR-2$\ell$ and SR-3$\ell $. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with the best fit normalizations from the simultaneous fit of the BDT score distributions to the data ("postfit"). The last bin includes the overflow contribution. |
png pdf |
Additional Figure 18:
Comparison of the number of observed (points) and predicted (colored histograms) events in the $ p_{\mathrm{T}}^{\mathrm{miss}} $ distribution in the $ \mathrm{t\bar{t}t\bar{t}} $ class of the combined SR-2$\ell$ and SR-3$\ell $. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with the best fit normalizations from the simultaneous fit of the BDT score distributions to the data ("postfit"). The last bin includes the overflow contribution. |
png pdf |
Additional Figure 19:
Comparison of the number of observed (points) and predicted (colored histograms) events in the number of b jets distribution in the $ \mathrm{t\bar{t}t\bar{t}} $ class of the combined SR-2$\ell$ and SR-3$\ell $. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with the best fit normalizations from the simultaneous fit of the BDT score distributions to the data ("postfit"). The last bin includes the overflow contribution. |
png pdf |
Additional Figure 20:
Comparison of the number of observed (points) and predicted (colored histograms) events in the number of medium b jets distribution in the $ \mathrm{t\bar{t}t\bar{t}} $ class of the combined SR-2$\ell$ and SR-3$\ell $. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with the best fit normalizations from the simultaneous fit of the BDT score distributions to the data ("postfit"). The last bin includes the overflow contribution. |
png pdf |
Additional Figure 21:
Comparison of the number of observed (points) and predicted (colored histograms) events in the number of jets distribution in the $ \mathrm{t\bar{t}t\bar{t}} $ class of the combined SR-2$\ell$ and SR-3$\ell $. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with the best fit normalizations from the simultaneous fit of the BDT score distributions to the data ("postfit"). The last bin includes the overflow contribution. |
png pdf |
Additional Figure 22:
Comparison of the number of observed (points) and predicted (colored histograms) events in the $ H_{\mathrm{T}} $ distribution in the $ \mathrm{t\bar{t}} $ class of the combined SR-2$\ell$ and SR-3$\ell $. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with the best fit normalizations from the simultaneous fit of the BDT score distributions to the data ("postfit"). The last bin includes the overflow contribution. |
png pdf |
Additional Figure 23:
Comparison of the number of observed (points) and predicted (colored histograms) events in the $ p_{\mathrm{T}}^{\mathrm{miss}} $ distribution in the $ \mathrm{t\bar{t}} $ class of the combined SR-2$\ell$ and SR-3$\ell $. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with the best fit normalizations from the simultaneous fit of the BDT score distributions to the data ("postfit"). The last bin includes the overflow contribution. |
png pdf |
Additional Figure 24:
Comparison of the number of observed (points) and predicted (colored histograms) events in the number of b jets distribution in the $ \mathrm{t\bar{t}} $ class of the combined SR-2$\ell$ and SR-3$\ell $. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with the best fit normalizations from the simultaneous fit of the BDT score distributions to the data ("postfit"). The last bin includes the overflow contribution. |
png pdf |
Additional Figure 25:
Comparison of the number of observed (points) and predicted (colored histograms) events in the number of medium b jets distribution in the $ \mathrm{t\bar{t}} $ class of the combined SR-2$\ell$ and SR-3$\ell $. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with the best fit normalizations from the simultaneous fit of the BDT score distributions to the data ("postfit"). The last bin includes the overflow contribution. |
png pdf |
Additional Figure 26:
Comparison of the number of observed (points) and predicted (colored histograms) events in the number of jets distribution in the $ \mathrm{t\bar{t}} $ class of the combined SR-2$\ell$ and SR-3$\ell $. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with the best fit normalizations from the simultaneous fit of the BDT score distributions to the data ("postfit"). The last bin includes the overflow contribution. |
png pdf |
Additional Figure 27:
Comparison of the number of observed (points) and predicted (colored histograms) events in the $ H_{\mathrm{T}} $ distribution in the $ \mathrm{t\bar{t}}$X class of the combined SR-2$\ell$ and SR-3$\ell $. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with the best fit normalizations from the simultaneous fit of the BDT score distributions to the data ("postfit"). The last bin includes the overflow contribution. |
png pdf |
Additional Figure 28:
Comparison of the number of observed (points) and predicted (colored histograms) events in the $ p_{\mathrm{T}}^{\mathrm{miss}} $ distribution in the $ \mathrm{t\bar{t}}$X class of the combined SR-2$\ell$ and SR-3$\ell $. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with the best fit normalizations from the simultaneous fit of the BDT score distributions to the data ("postfit"). The last bin includes the overflow contribution. |
png pdf |
Additional Figure 29:
Comparison of the number of observed (points) and predicted (colored histograms) events in the number of b jets distribution in the $ \mathrm{t\bar{t}}$X class of the combined SR-2$\ell$ and SR-3$\ell $. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with the best fit normalizations from the simultaneous fit of the BDT score distributions to the data ("postfit"). The last bin includes the overflow contribution. |
png pdf |
Additional Figure 30:
Comparison of the number of observed (points) and predicted (colored histograms) events in the number of medium b jets distribution in the $ \mathrm{t\bar{t}}$X class of the combined SR-2$\ell$ and SR-3$\ell $. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with the best fit normalizations from the simultaneous fit of the BDT score distributions to the data ("postfit"). The last bin includes the overflow contribution. |
png pdf |
Additional Figure 31:
Comparison of the number of observed (points) and predicted (colored histograms) events in the number of jets distribution in the $ \mathrm{t\bar{t}}$X class of the combined SR-2$\ell$ and SR-3$\ell $. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with the best fit normalizations from the simultaneous fit of the BDT score distributions to the data ("postfit"). The last bin includes the overflow contribution. |
png pdf |
Additional Figure 32:
Two-dimensional scan of the $ \mathrm{t\bar{t}t\bar{t}} $ and $ \mathrm{ttt} $ cross sections. The shading quantified by the color scale on the right reflects the negative log-likelihood difference with respect to the best fit value that is indicated by the white filled star. The 68% (solid line) and 95% (dashed line) CL contours are shown for the observed result. The white empty cross indicates the SM prediction. The correlation $ \rho $ between the two measured cross sections is $-$0.94. |
png pdf |
Additional Figure 33:
Shape comparison of the predicted $ \mathrm{t\bar{t}t\bar{t}} $ (solid red line), $ \mathrm{ttt} $ (dashed green line), and combined other background (dotted black line) contributions in the BDT score $ \mathrm{t\bar{t}t\bar{t}} $ in the $ \mathrm{t\bar{t}t\bar{t}} $ class of SR-2$\ell$. |
png pdf |
Additional Figure 34:
Comparison of the number of observed (points) and predicted (colored histograms) events in the SR-2$\ell$ distribution of $ \Delta R $ between the leading and subleading lepton. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data ("prefit"). The last bin includes the overflow contribution. |
png pdf |
Additional Figure 35:
Comparison of the number of observed (points) and predicted (colored histograms) events in the SR-3$\ell $ distribution of $ \Delta R $ between the leading and subleading lepton. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data ("prefit"). The last bin includes the overflow contribution. |
png pdf |
Additional Figure 36:
Comparison of the number of observed (points) and predicted (colored histograms) events in the SR-2$\ell$ distribution of the smallest $ \Delta R $ between any two b jets. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data ("prefit"). The last bin includes the overflow contribution. No values smaller than 0.4 are found since this is the jet radius. |
png pdf |
Additional Figure 37:
Comparison of the number of observed (points) and predicted (colored histograms) events in the SR-3$\ell $ distribution of the smallest $ \Delta R $ between any two b jets. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data ("prefit"). The last bin includes the overflow contribution. No values smaller than 0.4 are found since this is the jet radius. |
png pdf |
Additional Figure 38:
Comparison of the number of observed (points) and predicted (colored histograms) events in the SR-2$\ell$ distribution of the three-jet mass closest to the top quark mass. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data ("prefit"). The first and last bins include the under- and overflow contributions, respectively. |
png pdf |
Additional Figure 39:
Comparison of the number of observed (points) and predicted (colored histograms) events in the SR-3$\ell $ distribution of the three-jet mass closest to the top quark mass. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data ("prefit"). The first and last bins include the under- and overflow contributions, respectively. |
png pdf |
Additional Figure 40:
Comparison of the number of observed (points) and predicted (colored histograms) events in the SR-2$\ell$ distribution of the second-highest DEEPJET score of any jet. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data ("prefit"). The last bin includes the overflow contribution. No values smaller than 0.04 are found because of the event selection requirement of two b jets. |
png pdf |
Additional Figure 41:
Comparison of the number of observed (points) and predicted (colored histograms) events in the SR-3$\ell $ distribution of the second-highest DEEPJET score of any jet. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown before the fit to the data ("prefit"). The last bin includes the overflow contribution. No values smaller than 0.04 are found because of the event selection requirement of two b jets. |
png pdf |
Additional Figure 42:
Two-dimensional scan of the $ \mathrm{t\bar{t}t\bar{t}} $ and $ \mathrm{t\bar{t}W} $ cross sections as obtained from the fit with the $ \mathrm{t\bar{t}t\bar{t}} $, $ \mathrm{t\bar{t}W} $, and $ \mathrm{t\bar{t}W} $ cross sections as free parameters. The shading quantified by the color scale on the right reflects the negative log-likelihood difference with respect to the best fit value that is indicated by the white filled star. The 68% (solid line) and 95% (dashed line) CL contours are shown for the observed result. The white empty cross indicates the SM prediction. The correlation $ \rho $ between the two measured cross sections is $ + $0.07. |
png pdf |
Additional Figure 43:
Two-dimensional scan of the $ \mathrm{t\bar{t}t\bar{t}} $ and $ \mathrm{t\bar{t}Z} $ cross sections as obtained from the fit with the $ \mathrm{t\bar{t}t\bar{t}} $, $ \mathrm{t\bar{t}W} $, and $ \mathrm{t\bar{t}W} $ cross sections as free parameters. The shading quantified by the color scale on the right reflects the negative log-likelihood difference with respect to the best fit value that is indicated by the white filled star. The 68% (solid line) and 95% (dashed line) CL contours are shown for the observed result. The white empty cross indicates the SM prediction. The correlation $ \rho $ between the two measured cross sections is $ + $0.11. |
png pdf |
Additional Figure 44:
Two-dimensional scan of the $ \mathrm{t\bar{t}W} $ and $ \mathrm{t\bar{t}Z} $ cross sections as obtained from the fit with the $ \mathrm{t\bar{t}t\bar{t}} $, $ \mathrm{t\bar{t}W} $, and $ \mathrm{t\bar{t}W} $ cross sections as free parameters. The shading quantified by the color scale on the right reflects the negative log-likelihood difference with respect to the best fit value that is indicated by the white filled star. The 68% (solid line) and 95% (dashed line) CL contours are shown for the observed result. The white empty cross indicates the SM prediction. The correlation $ \rho $ between the two measured cross sections is $ + $0.12. |
png pdf |
Additional Figure 45:
Comparison of the number of observed (points) and predicted (colored histograms) events in the $ H_{\mathrm{T}} $ distribution in the combined $ \mathrm{t\bar{t}t\bar{t}} $ and $ \mathrm{t\bar{t}X} $ class of SR-2$\ell$ in the $ \mu\mu $ category. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with the best fit normalizations from the simultaneous fit of the BDT score distributions to the data ("postfit"). The last bin includes the overflow contribution. |
png pdf |
Additional Figure 46:
Comparison of the number of observed (points) and predicted (colored histograms) events in the $ p_{\mathrm{T}}^{\mathrm{miss}} $ distribution in the combined $ \mathrm{t\bar{t}t\bar{t}} $ and $ \mathrm{t\bar{t}X} $ class of SR-2$\ell$ in the $ \mu\mu $ category. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with the best fit normalizations from the simultaneous fit of the BDT score distributions to the data ("postfit"). The last bin includes the overflow contribution. |
png pdf |
Additional Figure 47:
Comparison of the number of observed (points) and predicted (colored histograms) events in the number of b jets distribution in the combined $ \mathrm{t\bar{t}t\bar{t}} $ and $ \mathrm{t\bar{t}X} $ class of SR-2$\ell$ in the $ \mu\mu $ category. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with the best fit normalizations from the simultaneous fit of the BDT score distributions to the data ("postfit"). The last bin includes the overflow contribution. |
png pdf |
Additional Figure 48:
Comparison of the number of observed (points) and predicted (colored histograms) events in the number of medium b jets distribution in the combined $ \mathrm{t\bar{t}t\bar{t}} $ and $ \mathrm{t\bar{t}X} $ class of SR-2$\ell$ in the $ \mu\mu $ category. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with the best fit normalizations from the simultaneous fit of the BDT score distributions to the data ("postfit"). The last bin includes the overflow contribution. |
png pdf |
Additional Figure 49:
Comparison of the number of observed (points) and predicted (colored histograms) events in the number of jets distribution in the combined $ \mathrm{t\bar{t}t\bar{t}} $ and $ \mathrm{t\bar{t}X} $ class of SR-2$\ell$ in the $ \mu\mu $ category. The vertical bars on the points represent the statistical uncertainties in the data, and the hatched bands the total uncertainty in the predictions. The signal and background yields are shown with the best fit normalizations from the simultaneous fit of the BDT score distributions to the data ("postfit"). The last bin includes the overflow contribution. |
Additional Tables | |
png pdf |
Additional Table 1:
List of the input variables to the prompt-lepton ID BDTs. The nearest jet ($ \mathrm{j}_{\text{near}} $) is defined as the jet that includes the PF particle corresponding to the reconstructed lepton, and its momentum is recalibrated after subtracting the contribution from the lepton. The last two rows list input variables only used in the electron or muon ID BDTs, respectively, and are defined in Refs. [80, 83]. |
References | ||||
1 | G. Bevilacqua and M. Worek | Constraining BSM physics at the LHC: Four top final states with NLO accuracy in perturbative QCD | JHEP 07 (2012) 111 | 1206.3064 |
2 | J. Alwall et al. | The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations | JHEP 07 (2014) 079 | 1405.0301 |
3 | F. Maltoni, D. Pagani, and I. Tsinikos | Associated production of a top-quark pair with vector bosons at NLO in QCD: impact on $ {{\mathrm{t}\bar{\mathrm{t}}} \mathrm{H}} $ searches at the LHC | JHEP 02 (2016) 113 | 1507.05640 |
4 | R. Frederix, D. Pagani, and M. Zaro | Large NLO corrections in $ {{\mathrm{t}\bar{\mathrm{t}}} \mathrm{W}^{\pm}} $ and $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ hadroproduction from supposedly subleading EW contributions | JHEP 02 (2018) 031 | 1711.02116 |
5 | T. Ježo and M. Kraus | Hadroproduction of four top quarks in the POWHEG \textscbox | PRD 105 (2022) 114024 | 2110.15159 |
6 | M. van Beekveld, A. Kulesza, and L. Moreno Valero | Threshold resummation for the production of four top quarks at the LHC | 2212.03259 | |
7 | Q.-H. Cao, S.-L. Chen, and Y. Liu | Probing Higgs width and top quark Yukawa coupling from $ {\mathrm{t}\bar{\mathrm{t}}} \mathrm{H} $ and $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ productions | PRD 95 (2017) 053004 | 1602.01934 |
8 | Q.-H. Cao et al. | Limiting top quark-Higgs boson interaction and Higgs-boson width from multitop productions | PRD 99 (2019) 113003 | 1901.04567 |
9 | CMS Collaboration | Measurement of the Higgs boson production rate in association with top quarks in final states with electrons, muons, and hadronically decaying tau leptons at $ \sqrt{s}= $ 13 TeV | EPJC 81 (2021) 378 | CMS-HIG-19-008 2011.03652 |
10 | CMS Collaboration | Measurement of the top quark Yukawa coupling from $ \mathrm{t} \bar{\mathrm{t}} $ kinematic distributions in the lepton+jets final state in proton-proton collisions at $ \sqrt{s}= $ 13 TeV | PRD 100 (2019) 072007 | CMS-TOP-17-004 1907.01590 |
11 | CMS Collaboration | Measurement of the top quark Yukawa coupling from $ \mathrm{t} \bar{\mathrm{t}} $ kinematic distributions in the dilepton final state in proton-proton collisions at $ \sqrt{s}= $ 13 TeV | PRD 102 (2020) 092013 | CMS-TOP-19-008 2009.07123 |
12 | D. Dicus, A. Stange, and S. Willenbrock | Higgs decay to top quarks at hadron colliders | PLB 333 (1994) 126 | hep-ph/9404359 |
13 | N. Craig et al. | The hunt for the rest of the Higgs bosons | JHEP 06 (2015) 137 | 1504.04630 |
14 | N. Craig et al. | Heavy Higgs bosons at low $ \tan\beta $: from the LHC to 100 TeV | JHEP 01 (2017) 018 | 1605.08744 |
15 | Anisha et al. | On the BSM reach of four top production at the LHC | Submitted to JHEP, 2023 | 2302.08281 |
16 | H. Nilles | Supersymmetry, supergravity and particle physics | Phys. Rept. 110 (1984) 1 | |
17 | G. Farrar and P. Fayet | Phenomenology of the production, decay, and detection of new hadronic states associated with supersymmetry | PLB 76 (1978) 575 | |
18 | M. Toharia and J. Wells | Gluino decays with heavier scalar superpartners | JHEP 02 (2006) 015 | hep-ph/0503175 |
19 | T. Plehn and T. Tait | Seeking sgluons | JPG 36 (2009) 075001 | 0810.3919 |
20 | S. Calvet, B. Fuks, P. Gris, and L. Valery | Searching for sgluons in multitop events at a center-of-mass energy of 8 TeV | JHEP 04 (2013) 043 | 1212.3360 |
21 | L. Beck et al. | Probing top-philic sgluons with LHC Run I data | PLB 746 (2015) 48 | 1501.07580 |
22 | L. Darmé , B. Fuks, and M. Goodsell | Cornering sgluons with four-top-quark events | PLB 784 (2018) 223 | 1805.10835 |
23 | K. Kumar, T. M. P. Tait, and R. Vega-Morales | Manifestations of top compositeness at colliders | JHEP 05 (2009) 022 | 0901.3808 |
24 | G. Cacciapaglia et al. | Composite scalars at the LHC: the Higgs, the sextet and the octet | JHEP 11 (2015) 201 | 1507.02283 |
25 | O. Ducu, L. Heurtier, and J. Maurer | LHC signatures of a Z' mediator between dark matter and the SU(3) sector | JHEP 03 (2016) 006 | 1509.05615 |
26 | C. Degrande et al. | Non-resonant new physics in top pair production at hadron colliders | JHEP 03 (2011) 125 | 1010.6304 |
27 | C. Zhang | Constraining $ {\mathrm{q}\mathrm{q}\mathrm{t}\mathrm{t}} $ operators from four-top production: a case for enhanced EFT sensitivity | Chin. Phys. C 42 (2018) 023104 | 1708.05928 |
28 | N. Hartland et al. | A Monte Carlo global analysis of the standard model effective field theory: the top quark sector | JHEP 04 (2019) 100 | 1901.05965 |
29 | C. Englert, G. F. Giudice, A. Greljo, and M. McCullough | The $ \hat{\mathrm{H}} $-parameter: an oblique Higgs view | JHEP 09 (2019) 041 | 1903.07725 |
30 | G. Banelli et al. | The present and future of four top operators | JHEP 02 (2021) 043 | 2010.05915 |
31 | L. Darmé , B. Fuks, and F. Maltoni | Top-philic heavy resonances in four-top final states and their EFT interpretation | JHEP 09 (2021) 143 | 2104.09512 |
32 | SMEFiT Collaboration | Combined SMEFT interpretation of Higgs, diboson, and top quark data from the LHC | JHEP 11 (2021) 089 | 2105.00006 |
33 | R. Aoude, H. El Faham, F. Maltoni, and E. Vryonidou | Complete SMEFT predictions for four top quark production at hadron colliders | JHEP 10 (2022) 163 | 2208.04962 |
34 | ATLAS Collaboration | The ATLAS experiment at the CERN Large Hadron Collider | JINST 3 (2008) S08003 | |
35 | CMS Collaboration | The CMS experiment at the CERN LHC | JINST 3 (2008) S08004 | |
36 | CMS Collaboration | Search for physics beyond the standard model in events with two leptons of same sign, missing transverse momentum, and jets in proton-proton collisions at $ \sqrt{s}= $ 13 TeV | EPJC 77 (2017) 578 | CMS-SUS-16-035 1704.07323 |
37 | CMS Collaboration | Search for standard model production of four top quarks with same-sign and multilepton final states in proton-proton collisions at $ \sqrt{s}= $ 13 TeV | EPJC 78 (2018) 140 | CMS-TOP-17-009 1710.10614 |
38 | ATLAS Collaboration | Search for new phenomena in events with same-charge leptons and b jets in pp collisions at $ \sqrt{s}=$ 13 TeV with the ATLAS detector | JHEP 12 (2018) 039 | 1807.11883 |
39 | ATLAS Collaboration | Search for four-top-quark production in the single-lepton and opposite-sign dilepton final states in pp collisions at $ \sqrt{s}=$ 13 TeV with the ATLAS detector | PRD 99 (2019) 052009 | 1811.02305 |
40 | CMS Collaboration | Search for the production of four top quarks in the single-lepton and opposite-sign dilepton final states in proton-proton collisions at $ \sqrt{s}= $ 13 TeV | JHEP 11 (2019) 082 | CMS-TOP-17-019 1906.02805 |
41 | CMS Collaboration | Search for production of four top quarks in final states with same-sign or multiple leptons in proton-proton collisions at $ \sqrt{s}= $ 13 TeV | EPJC 80 (2020) 75 | CMS-TOP-18-003 1908.06463 |
42 | ATLAS Collaboration | Evidence for $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ production in the multilepton final state in proton-proton collisions at $ \sqrt{s}=$ 13 TeV with the ATLAS detector | EPJC 80 (2020) 1085 | 2007.14858 |
43 | ATLAS Collaboration | Measurement of the $ {\mathrm{t}\bar{\mathrm{t}}} {\mathrm{t}\bar{\mathrm{t}}} $ production cross section in pp collisions at $ \sqrt{s}=$ 13 TeV with the ATLAS detector | JHEP 11 (2021) 118 | 2106.11683 |
44 | CMS Collaboration | Evidence for four-top quark production in proton-proton collisions at $ \sqrt{s}= $ 13 TeV | Submitted to PLB, 2023 | CMS-TOP-21-005 2303.03864 |
45 | F. Blekman, F. Déliot, V. Dutta, and E. Usai | Four-top quark physics at the LHC | Universe 8 (2022) 638 | 2208.04085 |
46 | L. Lyons and N. Wardle | Statistical issues in searches for new phenomena in high energy physics | JPG 45 (2018) 033001 | |
47 | ATLAS Collaboration | Observation of four-top-quark production in the multilepton final state with the ATLAS detector | Submitted to EPJC, 2023 | 2303.15061 |
48 | CMS Collaboration | HEPData record for this analysis | link | |
49 | CMS Collaboration | Performance of the CMS Level-1 trigger in proton-proton collisions at $ \sqrt{s}= $ 13 TeV | JINST 15 (2020) P10017 | CMS-TRG-17-001 2006.10165 |
50 | CMS Collaboration | The CMS trigger system | JINST 12 (2017) P01020 | CMS-TRG-12-001 1609.02366 |
51 | CMS Collaboration | Particle-flow reconstruction and global event description with the CMS detector | JINST 12 (2017) P10003 | CMS-PRF-14-001 1706.04965 |
52 | CMS Collaboration | Technical proposal for the Phase-II upgrade of the Compact Muon Solenoid | CMS Technical Proposal CERN-LHCC-2015-010, CMS-TDR-15-02, 2015 CDS |
|
53 | M. Cacciari, G. P. Salam, and G. Soyez | The anti-$ k_{\mathrm{T}} $ jet clustering algorithm | JHEP 04 (2008) 063 | 0802.1189 |
54 | M. Cacciari, G. P. Salam, and G. Soyez | FASTJET user manual | EPJC 72 (2012) 1896 | 1111.6097 |
55 | CMS Collaboration | Jet energy scale and resolution in the CMS experiment in pp collisions at 8 TeV | JINST 12 (2017) P02014 | CMS-JME-13-004 1607.03663 |
56 | CMS Collaboration | Performance of missing transverse momentum reconstruction in proton-proton collisions at $ \sqrt{s}= $ 13 TeV using the CMS detector | JINST 14 (2019) P07004 | CMS-JME-17-001 1903.06078 |
57 | CMS Collaboration | Identification of heavy-flavour jets with the CMS detector in pp collisions at 13 TeV | JINST 13 (2018) P05011 | CMS-BTV-16-002 1712.07158 |
58 | E. Bols et al. | Jet flavour classification using DeepJet | JINST 15 (2020) P12012 | 2008.10519 |
59 | CMS Collaboration | Performance summary of AK4 jet b tagging with data from proton-proton collisions at 13 TeV with the CMS detector | CMS Detector Performance Note CMS-DP-2023-005, 2023 CDS |
|
60 | P. Artoisenet, R. Frederix, O. Mattelaer, and R. Rietkerk | Automatic spin-entangled decays of heavy resonances in Monte Carlo simulations | JHEP 03 (2013) 015 | 1212.3460 |
61 | P. Nason | A new method for combining NLO QCD with shower Monte Carlo algorithms | JHEP 11 (2004) 040 | hep-ph/0409146 |
62 | S. Frixione, G. Ridolfi, and P. Nason | A positive-weight next-to-leading-order Monte Carlo for heavy flavour hadroproduction | JHEP 09 (2007) 126 | 0707.3088 |
63 | S. Frixione, P. Nason, and C. Oleari | Matching NLO QCD computations with parton shower simulations: the POWHEG method | JHEP 11 (2007) 070 | 0709.2092 |
64 | S. Alioli, P. Nason, C. Oleari, and E. Re | NLO single-top production matched with shower in POWHEG: $ s $- and $ t $-channel contributions | JHEP 09 (2009) 111 | 0907.4076 |
65 | P. Nason and C. Oleari | NLO Higgs boson production via vector-boson fusion matched with shower in POWHEG | JHEP 02 (2010) 037 | 0911.5299 |
66 | S. Alioli, P. Nason, C. Oleari, and E. Re | A general framework for implementing NLO calculations in shower Monte Carlo programs: the POWHEG box | JHEP 06 (2010) 043 | 1002.2581 |
67 | E. Re | Single-top $ {\mathrm{W}\mathrm{t}} $-channel production matched with parton showers using the POWHEG method | EPJC 71 (2011) 1547 | 1009.2450 |
68 | E. Bagnaschi, G. Degrassi, P. Slavich, and A. Vicini | Higgs production via gluon fusion in the POWHEG approach in the SM and in the MSSM | JHEP 02 (2012) 088 | 1111.2854 |
69 | P. Nason and G. Zanderighi | $ {\mathrm{W^+}\mathrm{W^-}} $, $ {\mathrm{W}\mathrm{Z}} $ and $ {\mathrm{Z}\mathrm{Z}} $ production in the POWHEG-box-v2 | EPJC 74 (2014) 2702 | 1311.1365 |
70 | J. M. Campbell and R. K. Ellis | An update on vector boson pair production at hadron colliders | PRD 60 (1999) 113006 | hep-ph/9905386 |
71 | J. M. Campbell, R. K. Ellis, and C. Williams | Vector boson pair production at the LHC | JHEP 07 (2011) 018 | 1105.0020 |
72 | J. M. Campbell, R. K. Ellis, and W. T. Giele | A multi-threaded version of MCFM | EPJC 75 (2015) 246 | 1503.06182 |
73 | NNPDF Collaboration | Parton distributions from high-precision collider data | EPJC 77 (2017) 663 | 1706.00428 |
74 | T. Sjöstrand et al. | An introduction to PYTHIA8.2 | Comput. Phys. Commun. 191 (2015) 159 | 1410.3012 |
75 | CMS Collaboration | Extraction and validation of a new set of CMS PYTHIA8 tunes from underlying-event measurements | EPJC 80 (2020) 4 | CMS-GEN-17-001 1903.12179 |
76 | R. Frederix and S. Frixione | Merging meets matching in MC@NLO | JHEP 12 (2012) 061 | 1209.6215 |
77 | J. Alwall et al. | Comparative study of various algorithms for the merging of parton showers and matrix elements in hadronic collisions | EPJC 53 (2008) 473 | 0706.2569 |
78 | S. Bolognesi et al. | On the spin and parity of a single-produced resonance at the LHC | PRD 86 (2012) 095031 | 1208.4018 |
79 | GEANT4 Collaboration | GEANT 4---a simulation toolkit | NIM A 506 (2003) 250 | |
80 | CMS Collaboration | Electron and photon reconstruction and identification with the CMS experiment at the CERN LHC | JINST 16 (2021) P05014 | CMS-EGM-17-001 2012.06888 |
81 | CMS Collaboration | ECAL 2016 refined calibration and Run2 summary plots | CMS Detector Performance Note CMS-DP-2020-021, 2020 CDS |
|
82 | CMS Collaboration | Performance of electron reconstruction and selection with the CMS detector in proton-proton collisions at $ \sqrt{s}= $ 8 TeV | JINST 10 (2015) P06005 | CMS-EGM-13-001 1502.02701 |
83 | CMS Collaboration | Performance of the CMS muon detector and muon reconstruction with proton-proton collisions at $ \sqrt{s}= $ 13 TeV | JINST 13 (2018) P06015 | CMS-MUO-16-001 1804.04528 |
84 | CMS Collaboration | Performance of CMS muon reconstruction in cosmic-ray events | JINST 5 (2010) T03022 | CMS-CFT-09-014 0911.4994 |
85 | CMS Collaboration | Performance of the reconstruction and identification of high-momentum muons in proton-proton collisions at $ \sqrt{s}= $ 13 TeV | JINST 15 (2020) P02027 | CMS-MUO-17-001 1912.03516 |
86 | K. Rehermann and B. Tweedie | Efficient identification of boosted semileptonic top quarks at the LHC | JHEP 03 (2011) 059 | 1007.2221 |
87 | T. Chen and C. Guestrin | XGBoost: A scalable tree boosting system | in 22nd ACM SIGKDD Int. Conf. on Knowledge Discovery and Data Mining, San Francisco, 2016 link |
1603.02754 |
88 | CMS Collaboration | Evidence for associated production of a Higgs boson with a top quark pair in final states with electrons, muons, and hadronically decaying $ \tau $ leptons at $ \sqrt{s}= $ 13 TeV | JHEP 08 (2018) 066 | CMS-HIG-17-018 1803.05485 |
89 | CMS Collaboration | Observation of single top quark production in association with a Z boson in proton-proton collisions at $ \sqrt{s}= $ 13 TeV | PRL 122 (2019) 132003 | CMS-TOP-18-008 1812.05900 |
90 | CMS Collaboration | Search for electroweak production of charginos and neutralinos in proton-proton collisions at $ \sqrt{s}= $ 13 TeV | JHEP 04 (2022) 147 | CMS-SUS-19-012 2106.14246 |
91 | CMS Collaboration | Measurements of the electroweak diboson production cross sections in proton-proton collisions at $ \sqrt{s}= $ 5.02 TeV using leptonic decays | PRL 127 (2021) 191801 | CMS-SMP-20-012 2107.01137 |
92 | CMS Collaboration | 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 | JHEP 02 (2022) 107 | CMS-TOP-20-010 2111.02860 |
93 | CMS Collaboration | Identification of prompt and isolated muons using multivariate techniques at the CMS experiment in proton-proton collisions at $ \sqrt{s}= $ 13 TeV | CMS Physics Analysis Summary, 2023 CMS-PAS-MUO-22-001 |
CMS-PAS-MUO-22-001 |
94 | Particle Data Group , R. L. Workman et al. | Review of particle physics | Prog. Theor. Exp. Phys. 2022 (2022) 083C01 | |
95 | H. Voss, A. Höcker, J. Stelzer, and F. Tegenfeldt | TMVA, the toolkit for multivariate data analysis with ROOT | in 11th Int. Workshop on Advanced Computing and Analysis Techniques in Phys. Research (ACAT), Amsterdam, 2017 link |
physics/0703039 |
96 | C. G. Lester and D. J. Summers | Measuring masses of semiinvisibly decaying particles pair produced at hadron colliders | PLB 463 (1999) 99 | hep-ph/9906349 |
97 | C. G. Lester | The stransverse mass, $ m_{\mathrm{T2}} $, in special cases | JHEP 05 (2011) 076 | 1103.5682 |
98 | R. Frederix and I. Tsinikos | On improving NLO merging for $ {{\mathrm{t}\bar{\mathrm{t}}} \mathrm{W}} $ production | JHEP 11 (2021) 029 | 2108.07826 |
99 | A. Kulesza et al. | Associated top quark pair production with a heavy boson: differential cross sections at NLO+NNLL accuracy | EPJC 80 (2020) 428 | 2001.03031 |
100 | G. Durieux | Triple top-quark production at NLO in QCD | link | |
101 | CMS Collaboration | Measurement of the associated production of a single top quark and a Z boson in pp collisions at $ \sqrt{s}= $ 13 TeV | PLB 779 (2018) 358 | CMS-TOP-16-020 1712.02825 |
102 | CMS Collaboration | Measurement of top quark pair production in association with a Z boson in proton-proton collisions at $ \sqrt{s}= $ 13 TeV | JHEP 03 (2020) 056 | CMS-TOP-18-009 1907.11270 |
103 | CMS Collaboration | Search for new physics in same-sign dilepton events in proton-proton collisions at $ \sqrt{s}= $ 13 TeV | EPJC 76 (2016) 439 | CMS-SUS-15-008 1605.03171 |
104 | CMS Collaboration | Precision luminosity measurement in proton-proton collisions at $ \sqrt{s}= $ 13 TeV in 2015 and 2016 at CMS | EPJC 81 (2021) 800 | CMS-LUM-17-003 2104.01927 |
105 | CMS Collaboration | CMS luminosity measurement for the 2017 data-taking period at $ \sqrt{s}= $ 13 TeV | CMS Physics Analysis Summary, 2018 CMS-PAS-LUM-17-004 |
CMS-PAS-LUM-17-004 |
106 | CMS Collaboration | CMS luminosity measurement for the 2018 data-taking period at $ \sqrt{s}= $ 13 TeV | CMS Physics Analysis Summary, 2019 CMS-PAS-LUM-18-002 |
CMS-PAS-LUM-18-002 |
107 | CMS Collaboration | Measurements of inclusive W and Z cross sections in pp collisions at $ \sqrt{s}= $ 7 TeV | JHEP 01 (2011) 080 | CMS-EWK-10-002 1012.2466 |
108 | CMS Collaboration | Measurements of the $ {\mathrm{p}\mathrm{p}\to\mathrm{W}\mathrm{Z}} $ inclusive and differential production cross section and constraints on charged anomalous triple gauge couplings at $ \sqrt{s}= $ 13 TeV | JHEP 04 (2019) 122 | CMS-SMP-18-002 1901.03428 |
109 | CMS Collaboration | Measurements of the $ {\mathrm{p}\mathrm{p}\to\mathrm{Z}\mathrm{Z}} $ production cross section and the $ {\mathrm{Z}\to4\ell} $ branching fraction, and constraints on anomalous triple gauge couplings at $ \sqrt{s}= $ 13 TeV | EPJC 78 (2018) 165 | CMS-SMP-16-017 1709.08601 |
110 | CMS Collaboration | $ {\mathrm{W^+}\mathrm{W^-}} $ boson pair production in proton-proton collisions at $ \sqrt{s}= $ 13 TeV | PRD 102 (2020) 092001 | CMS-SMP-18-004 2009.00119 |
111 | CMS Collaboration | Measurement of the inclusive and differential $ {{\mathrm{t}\bar{\mathrm{t}}} \gamma} $ cross sections in the dilepton channel and effective field theory interpretation in proton-proton collisions at $ \sqrt{s}= $ 13 TeV | JHEP 05 (2022) 091 | CMS-TOP-21-004 2201.07301 |
112 | M. Cacciari et al. | The $ \mathrm{t} \bar{\mathrm{t}} $ cross-section at 1.8 and 1.96 TeV: a study of the systematics due to parton densities and scale dependence | JHEP 04 (2004) 068 | hep-ph/0303085 |
113 | J. Butterworth et al. | PDF4LHC recommendations for LHC Run II | JPG 43 (2016) 023001 | 1510.03865 |
114 | CMS Collaboration | Measurement of the cross section for $ \mathrm{t} \bar{\mathrm{t}} $ production with additional jets and b jets in pp collisions at $ \sqrt{s}= $ 13 TeV | JHEP 07 (2020) 125 | CMS-TOP-18-002 2003.06467 |
115 | ATLAS and CMS Collaborations, and LHC Higgs Combination Group | Procedure for the LHC Higgs boson search combination in Summer 2011 | Technical Report CMS-NOTE-2011-005, ATL-PHYS-PUB-2011-11, 2011 | |
116 | G. Cowan, K. Cranmer, E. Gross, and O. Vitells | Asymptotic formulae for likelihood-based tests of new physics | EPJC 71 (2011) 1554 | 1007.1727 |
117 | R. Barlow and C. Beeston | Fitting using finite Monte Carlo samples | Comput. Phys. Commun. 77 (1993) 219 | |
118 | J. S. Conway | Incorporating nuisance parameters in likelihoods for multisource spectra | in Workshop on Statistical Issues Related to Discovery Claims in Search Experiments and Unfolding (PHYSTAT), Geneva, 2011 link |
1103.0354 |
119 | CMS Collaboration | Measurement of the cross section of top quark-antiquark pair production in association with a W boson in proton-proton collisions at $ \sqrt{s}= $ 13 TeV | Accepted by JHEP, 2022 | CMS-TOP-21-011 2208.06485 |
Compact Muon Solenoid LHC, CERN |