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CMS-B2G-17-011 ; CERN-EP-2018-069
Search for vector-like T and B quark pairs in final states with leptons at $\sqrt{s} = $ 13 TeV
JHEP 08 (2018) 177
Abstract: A search is presented for pair production of heavy vector-like T and B quarks in proton-proton collisions at $\sqrt{s} = $ 13 TeV. The data sample corresponds to an integrated luminosity of 35.9 fb$^{-1}$, collected with the CMS detector at the CERN LHC in 2016. Pair production of T quarks would result in a wide range of final states, since vector-like T quarks of charge 2$e$/3 are predicted to decay to bW, tZ, and tH. Likewise, vector-like B quarks are predicted to decay to tW, bZ, and bH. Three channels are considered, corresponding to final states with a single lepton, two leptons with the same sign of the electric charge, or at least three leptons. The results exclude T quarks with masses below 1140-1300 GeV and B quarks with masses below 910-1240 GeV for various branching fraction combinations, extending the reach of previous CMS searches by 200-600 GeV. These are the strongest exclusion limits to date for T quarks with a branching fraction to tZ greater than ${\approx}$ 0.5 and for B quarks with a branching fraction to tW less than ${\approx}$ 0.6.
Figures & Tables Summary References CMS Publications
Figures

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Figure 1:
Leading order Feynman diagrams showing pair production and decays of $ {{\mathrm {T}} {\overline {\mathrm {T}}}} $ (left) and $ {{\mathrm {B}} {\overline {\mathrm {B}}}} $ (right).

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Figure 1-a:
Leading order Feynman diagrams showing pair production and decays of $ {{\mathrm {T}} {\overline {\mathrm {T}}}} $.

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Figure 1-b:
Leading order Feynman diagrams showing pair production and decays of $ {{\mathrm {B}} {\overline {\mathrm {B}}}} $.

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Figure 2:
Distributions of W and H tagging input variables after all selection requirements: pruned mass in AK8 jets with $\tau _2/\tau _1 < $ 0.6 (upper left), $N$-subjettiness $\tau _2/\tau _1$ ratio in AK8 jets with pruned mass between 65-105 GeV (upper right), pruned mass in AK8 jets with two b-tagged subjets (lower left), and number of b-tagged subjets in AK8 jets with pruned mass in the range 60-160 GeV (lower right). Vertical dashed lines mark the selection windows for each distribution. The black points are the data and the filled histograms show the simulated background distributions, grouped into categories as described in Section 3. The expected signal is shown by solid and dotted lines for T quark masses of 1.0 and 1.2 TeV. The final bin includes overflow events. Uncertainties, indicated by the hatched area, include both statistical and systematic components. The lower panel shows the difference between data and background divided by the total uncertainty.

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Figure 2-a:
Distributions of W and H tagging input variables after all selection requirements: pruned mass in AK8 jets with $\tau _2/\tau _1 < $ 0.6. Vertical dashed lines mark the selection windows for each distribution. The black points are the data and the filled histograms show the simulated background distributions, grouped into categories as described in Section 3. The expected signal is shown by solid and dotted lines for T quark masses of 1.0 and 1.2 TeV. The final bin includes overflow events. Uncertainties, indicated by the hatched area, include both statistical and systematic components. The lower panel shows the difference between data and background divided by the total uncertainty.

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Figure 2-b:
Distributions of W and H tagging input variables after all selection requirements: pruned mass in AK8 jets with $N$-subjettiness $\tau _2/\tau _1$ ratio in AK8 jets with pruned mass between 65-105 GeV. Vertical dashed lines mark the selection windows for each distribution. The black points are the data and the filled histograms show the simulated background distributions, grouped into categories as described in Section 3. The expected signal is shown by solid and dotted lines for T quark masses of 1.0 and 1.2 TeV. The final bin includes overflow events. Uncertainties, indicated by the hatched area, include both statistical and systematic components. The lower panel shows the difference between data and background divided by the total uncertainty.

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Figure 2-c:
Distributions of W and H tagging input variables after all selection requirements: pruned mass in AK8 jets with pruned mass in AK8 jets with two b-tagged subjets.Vertical dashed lines mark the selection windows for each distribution. The black points are the data and the filled histograms show the simulated background distributions, grouped into categories as described in Section 3. The expected signal is shown by solid and dotted lines for T quark masses of 1.0 and 1.2 TeV. The final bin includes overflow events. Uncertainties, indicated by the hatched area, include both statistical and systematic components. The lower panel shows the difference between data and background divided by the total uncertainty.

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Figure 2-d:
Distributions of W and H tagging input variables after all selection requirements: pruned mass in AK8 jets with number of b-tagged subjets in AK8 jets with pruned mass in the range 60-160 GeV. Vertical dashed lines mark the selection windows for each distribution. The black points are the data and the filled histograms show the simulated background distributions, grouped into categories as described in Section 3. The expected signal is shown by solid and dotted lines for T quark masses of 1.0 and 1.2 TeV. The final bin includes overflow events. Uncertainties, indicated by the hatched area, include both statistical and systematic components. The lower panel shows the difference between data and background divided by the total uncertainty.

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Figure 3:
The $ {{H_{\mathrm {T}}} ^{\text {lep}}} $ distributions in events with at least two jets after the SS dilepton selection and Z-boson/quarkonia vetoes, for the $ {\mathrm {e}} {\mathrm {e}}$, $ {\mathrm {e}}\mu $, and $\mu \mu $ categories, and for the combination of all categories. The black points are the data and the filled histograms show the background distributions, with simulated backgrounds grouped into categories as described in Section 3. The expected signal is shown by solid and dotted lines for T quark masses of 1.0 and 1.2 TeV. The final bin includes overflow events. Uncertainties, indicated by the hatched area, include both statistical and systematic components. The lower panel shows the difference between data and background divided by the total uncertainty. Accepted events are required to have $ {{H_{\mathrm {T}}} ^{\text {lep}}} > $ 1200 GeV.

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Figure 3-a:
The $ {{H_{\mathrm {T}}} ^{\text {lep}}} $ distribution in events with at least two jets after the SS dilepton selection and Z-boson/quarkonia vetoes, for the $ {\mathrm {e}} {\mathrm {e}}$ category. The black points are the data and the filled histograms show the background distributions, with simulated backgrounds grouped into categories as described in Section 3. The expected signal is shown by solid and dotted lines for T quark masses of 1.0 and 1.2 TeV. The final bin includes overflow events. Uncertainties, indicated by the hatched area, include both statistical and systematic components. The lower panel shows the difference between data and background divided by the total uncertainty. Accepted events are required to have $ {{H_{\mathrm {T}}} ^{\text {lep}}} > $ 1200 GeV.

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Figure 3-b:
The $ {{H_{\mathrm {T}}} ^{\text {lep}}} $ distribution in events with at least two jets after the SS dilepton selection and Z-boson/quarkonia vetoes, for the $ {\mathrm {e}}\mu $ category. The black points are the data and the filled histograms show the background distributions, with simulated backgrounds grouped into categories as described in Section 3. The expected signal is shown by solid and dotted lines for T quark masses of 1.0 and 1.2 TeV. The final bin includes overflow events. Uncertainties, indicated by the hatched area, include both statistical and systematic components. The lower panel shows the difference between data and background divided by the total uncertainty. Accepted events are required to have $ {{H_{\mathrm {T}}} ^{\text {lep}}} > $ 1200 GeV.

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Figure 3-c:
The $ {{H_{\mathrm {T}}} ^{\text {lep}}} $ distribution in events with at least two jets after the SS dilepton selection and Z-boson/quarkonia vetoes, for the $\mu \mu $ categories. The black points are the data and the filled histograms show the background distributions, with simulated backgrounds grouped into categories as described in Section 3. The expected signal is shown by solid and dotted lines for T quark masses of 1.0 and 1.2 TeV. The final bin includes overflow events. Uncertainties, indicated by the hatched area, include both statistical and systematic components. The lower panel shows the difference between data and background divided by the total uncertainty. Accepted events are required to have $ {{H_{\mathrm {T}}} ^{\text {lep}}} > $ 1200 GeV.

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Figure 3-d:
The $ {{H_{\mathrm {T}}} ^{\text {lep}}} $ distribution in events with at least two jets after the SS dilepton selection and Z-boson/quarkonia vetoes, for the combination of $ {\mathrm {e}} {\mathrm {e}}$, $ {\mathrm {e}}\mu $, and $\mu \mu $ category. The black points are the data and the filled histograms show the background distributions, with simulated backgrounds grouped into categories as described in Section 3. The expected signal is shown by solid and dotted lines for T quark masses of 1.0 and 1.2 TeV. The final bin includes overflow events. Uncertainties, indicated by the hatched area, include both statistical and systematic components. The lower panel shows the difference between data and background divided by the total uncertainty. Accepted events are required to have $ {{H_{\mathrm {T}}} ^{\text {lep}}} > $ 1200 GeV.

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Figure 4:
Distributions of lepton $ {p_{\mathrm {T}}} $ (left) and $ {S_\mathrm {T}} $ (right) in the control region of the trilepton channel. The black points are the data (horizontal bars indicate the bin width) and the filled histograms show the background distributions, with simulated backgrounds grouped into categories as described in Section 3. The expected signal is shown by solid and dotted lines for T quark masses of 1.0 and 1.2 TeV. The final bin includes overflow events. Uncertainties, indicated by the hatched area, include both statistical and systematic components. The lower panel shows the difference between data and background divided by the total uncertainty.

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Figure 4-a:
Distribution of lepton $ {p_{\mathrm {T}}} $ in the control region of the trilepton channel. The black points are the data (horizontal bars indicate the bin width) and the filled histograms show the background distributions, with simulated backgrounds grouped into categories as described in Section 3. The expected signal is shown by solid and dotted lines for T quark masses of 1.0 and 1.2 TeV. The final bin includes overflow events. Uncertainties, indicated by the hatched area, include both statistical and systematic components. The lower panel shows the difference between data and background divided by the total uncertainty.

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Figure 4-b:
Distribution of lepton $ {S_\mathrm {T}} $ in the control region of the trilepton channel. The black points are the data (horizontal bars indicate the bin width) and the filled histograms show the background distributions, with simulated backgrounds grouped into categories as described in Section 3. The expected signal is shown by solid and dotted lines for T quark masses of 1.0 and 1.2 TeV. The final bin includes overflow events. Uncertainties, indicated by the hatched area, include both statistical and systematic components. The lower panel shows the difference between data and background divided by the total uncertainty.

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Figure 5:
Distributions of $ \mathrm{min}{[M(\ell, {\mathrm {b}})]} $ before the fit to data in the single-lepton W0 (left) or W1 (right) categories with 1, 2, or ${\geq}$3 (upper to lower) b-tagged jets. The black points are the data (horizontal bars indicate the bin width) and the filled histograms show the simulated background distributions, grouped into categories as described in Section 3. The expected signal is shown by solid and dotted lines for T quark masses of 1.0 and 1.2 TeV. The final bin includes overflow events. Uncertainties, indicated by the hatched area, include both statistical and systematic components The lower panel shows the difference between data and background divided by the total uncertainty.

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Figure 5-a:
Distribution of $ \mathrm{min}{[M(\ell, {\mathrm {b}})]} $ before the fit to data in the single-lepton W0 category with 1 b-tagged jet. The black points are the data (horizontal bars indicate the bin width) and the filled histograms show the simulated background distributions, grouped into categories as described in Section 3. The expected signal is shown by solid and dotted lines for T quark masses of 1.0 and 1.2 TeV. The final bin includes overflow events. Uncertainties, indicated by the hatched area, include both statistical and systematic components The lower panel shows the difference between data and background divided by the total uncertainty.

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Figure 5-b:
Distribution of $ \mathrm{min}{[M(\ell, {\mathrm {b}})]} $ before the fit to data in the single-lepton W1 category with 1 b-tagged jet. The black points are the data (horizontal bars indicate the bin width) and the filled histograms show the simulated background distributions, grouped into categories as described in Section 3. The expected signal is shown by solid and dotted lines for T quark masses of 1.0 and 1.2 TeV. The final bin includes overflow events. Uncertainties, indicated by the hatched area, include both statistical and systematic components The lower panel shows the difference between data and background divided by the total uncertainty.

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Figure 5-c:
Distribution of $ \mathrm{min}{[M(\ell, {\mathrm {b}})]} $ before the fit to data in the single-lepton W0 category with 2 b-tagged jets. The black points are the data (horizontal bars indicate the bin width) and the filled histograms show the simulated background distributions, grouped into categories as described in Section 3. The expected signal is shown by solid and dotted lines for T quark masses of 1.0 and 1.2 TeV. The final bin includes overflow events. Uncertainties, indicated by the hatched area, include both statistical and systematic components The lower panel shows the difference between data and background divided by the total uncertainty.

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Figure 5-d:
Distribution of $ \mathrm{min}{[M(\ell, {\mathrm {b}})]} $ before the fit to data in the single-lepton W1 category with 2 b-tagged jets. The black points are the data (horizontal bars indicate the bin width) and the filled histograms show the simulated background distributions, grouped into categories as described in Section 3. The expected signal is shown by solid and dotted lines for T quark masses of 1.0 and 1.2 TeV. The final bin includes overflow events. Uncertainties, indicated by the hatched area, include both statistical and systematic components The lower panel shows the difference between data and background divided by the total uncertainty.

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Figure 5-e:
Distribution of $ \mathrm{min}{[M(\ell, {\mathrm {b}})]} $ before the fit to data in the single-lepton W0 category with ${\geq}$3 b-tagged jets. The black points are the data (horizontal bars indicate the bin width) and the filled histograms show the simulated background distributions, grouped into categories as described in Section 3. The expected signal is shown by solid and dotted lines for T quark masses of 1.0 and 1.2 TeV. The final bin includes overflow events. Uncertainties, indicated by the hatched area, include both statistical and systematic components The lower panel shows the difference between data and background divided by the total uncertainty.

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Figure 5-f:
Distribution of $ \mathrm{min}{[M(\ell, {\mathrm {b}})]} $ before the fit to data in the single-lepton W1 category with ${\geq}$3 b-tagged jets. The black points are the data (horizontal bars indicate the bin width) and the filled histograms show the simulated background distributions, grouped into categories as described in Section 3. The expected signal is shown by solid and dotted lines for T quark masses of 1.0 and 1.2 TeV. The final bin includes overflow events. Uncertainties, indicated by the hatched area, include both statistical and systematic components The lower panel shows the difference between data and background divided by the total uncertainty.

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Figure 6:
Distributions of $ {S_\mathrm {T}} $ before the fit to data in the single-lepton H1b (left) or H2b (right) categories. Uncertainties, indicated by the hatched area, include both statistical and systematic components. The black points are the data (horizontal bars indicate the bin width) and the filled histograms show the simulated background distributions, grouped into categories as described in Section 3. The final bin includes overflow events. The expected signal is shown by solid and dotted lines for T quark masses of 1.0 and 1.2 TeV. The lower panel shows the difference between data and background divided by the total uncertainty.

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Figure 6-a:
Distribution of $ {S_\mathrm {T}} $ before the fit to data in the single-lepton H1b category. Uncertainties, indicated by the hatched area, include both statistical and systematic components. The black points are the data (horizontal bars indicate the bin width) and the filled histograms show the simulated background distributions, grouped into categories as described in Section 3. The final bin includes overflow events. The expected signal is shown by solid and dotted lines for T quark masses of 1.0 and 1.2 TeV. The lower panel shows the difference between data and background divided by the total uncertainty.

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Figure 6-b:
Distribution of $ {S_\mathrm {T}} $ before the fit to data in the single-lepton H2b category. Uncertainties, indicated by the hatched area, include both statistical and systematic components. The black points are the data (horizontal bars indicate the bin width) and the filled histograms show the simulated background distributions, grouped into categories as described in Section 3. The final bin includes overflow events. The expected signal is shown by solid and dotted lines for T quark masses of 1.0 and 1.2 TeV. The lower panel shows the difference between data and background divided by the total uncertainty.

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Figure 7:
Distributions of $ {S_\mathrm {T}} $ in the trilepton final state before the fit to data, in the four flavor categories. The black points are the data (horizontal bars indicate the bin width) and the filled histograms show the background distributions, with simulated backgrounds grouped into categories as described in Section 3. The expected signal is shown by solid and dotted lines for T quark masses of 1.0 and 1.2 TeV. The final bin includes overflow events. Uncertainties, indicated by the hatched area, include both statistical and systematic components. The lower panel shows the difference between data and background divided by the total uncertainty.

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Figure 7-a:
Distribution of $ {S_\mathrm {T}} $ in the trilepton final state before the fit to data, in the $eee$ category. The black points are the data (horizontal bars indicate the bin width) and the filled histograms show the background distributions, with simulated backgrounds grouped into categories as described in Section 3. The expected signal is shown by solid and dotted lines for T quark masses of 1.0 and 1.2 TeV. The final bin includes overflow events. Uncertainties, indicated by the hatched area, include both statistical and systematic components. The lower panel shows the difference between data and background divided by the total uncertainty.

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Figure 7-b:
Distribution of $ {S_\mathrm {T}} $ in the trilepton final state before the fit to data, in the $ee\mu$ category. The black points are the data (horizontal bars indicate the bin width) and the filled histograms show the background distributions, with simulated backgrounds grouped into categories as described in Section 3. The expected signal is shown by solid and dotted lines for T quark masses of 1.0 and 1.2 TeV. The final bin includes overflow events. Uncertainties, indicated by the hatched area, include both statistical and systematic components. The lower panel shows the difference between data and background divided by the total uncertainty.

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Figure 7-c:
Distribution of $ {S_\mathrm {T}} $ in the trilepton final state before the fit to data, in the $e\mu\mu$ category. The black points are the data (horizontal bars indicate the bin width) and the filled histograms show the background distributions, with simulated backgrounds grouped into categories as described in Section 3. The expected signal is shown by solid and dotted lines for T quark masses of 1.0 and 1.2 TeV. The final bin includes overflow events. Uncertainties, indicated by the hatched area, include both statistical and systematic components. The lower panel shows the difference between data and background divided by the total uncertainty.

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Figure 7-d:
Distribution of $ {S_\mathrm {T}} $ in the trilepton final state before the fit to data, in the $\mu\mu\mu$ category. The black points are the data (horizontal bars indicate the bin width) and the filled histograms show the background distributions, with simulated backgrounds grouped into categories as described in Section 3. The expected signal is shown by solid and dotted lines for T quark masses of 1.0 and 1.2 TeV. The final bin includes overflow events. Uncertainties, indicated by the hatched area, include both statistical and systematic components. The lower panel shows the difference between data and background divided by the total uncertainty.

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Figure 8:
The 95% CL expected and observed upper limits on the cross section of $ {{\mathrm {T}} {\overline {\mathrm {T}}}} $ (upper row) and $ {{\mathrm {B}} {\overline {\mathrm {B}}}} $ (lower row) production after combining all channels for the singlet (left) and doublet (right) branching fraction scenarios. The predicted cross sections are shown by the red curve, with the uncertainty indicated by the width of the line.

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Figure 8-a:
The 95% CL expected and observed upper limits on the cross section of $ {{\mathrm {T}} {\overline {\mathrm {T}}}} $ production after combining all channels for the singlet branching fraction scenario. The predicted cross sections are shown by the red curve, with the uncertainty indicated by the width of the line.

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Figure 8-b:
The 95% CL expected and observed upper limits on the cross section of $ {{\mathrm {T}} {\overline {\mathrm {T}}}} $ production after combining all channels for the doublet branching fraction scenario. The predicted cross sections are shown by the red curve, with the uncertainty indicated by the width of the line.

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Figure 8-c:
The 95% CL expected and observed upper limits on the cross section of $ {{\mathrm {B}} {\overline {\mathrm {B}}}} $ production after combining all channels for the singlet branching fraction scenario. The predicted cross sections are shown by the red curve, with the uncertainty indicated by the width of the line.

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Figure 8-d:
The 95% CL expected and observed upper limits on the cross section of $ {{\mathrm {B}} {\overline {\mathrm {B}}}} $ production after combining all channels for the doublet branching fraction scenario. The predicted cross sections are shown by the red curve, with the uncertainty indicated by the width of the line.

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Figure 9:
The 95% CL expected (left) and observed (right) lower limits on the T quark (upper row) and B quark (lower row) mass, expressed in GeV, after combining all channels for various branching fraction scenarios.

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Figure 9-a:
The 95% CL expected lower limits on the T quark mass, expressed in GeV, after combining all channels for various branching fraction scenarios.

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Figure 9-b:
The 95% CL observed lower limits on the T quark mass, expressed in GeV, after combining all channels for various branching fraction scenarios.

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Figure 9-c:
The 95% CL expected lower limits on the B quark mass, expressed in GeV, after combining all channels for various branching fraction scenarios.

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Figure 9-d:
The 95% CL observed lower limits on the B quark mass, expressed in GeV, after combining all channels for various branching fraction scenarios.
Tables

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Table 1:
Theoretical cross sections of $ {{\mathrm {T}} {\overline {\mathrm {T}}}} $ or $ {{\mathrm {B}} {\overline {\mathrm {B}}}} $ production, for various masses, assuming a width of 10 GeV at each mass point. The cross section uncertainties include contributions from uncertainties in the PDFs and uncertainties estimated by varying factorization and renormalization scales by a factor of two.

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Table 2:
Predicted and observed event yields in the aggregated control region categories of the single-lepton channel. Uncertainties include both statistical and systematic components.

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Table 3:
Summary of values for normalization uncertainties and dependencies for shape uncertainties. The symbol $\sigma $ denotes one standard deviation of the uncertainty and "env'' denotes an envelope of values. Background from opposite-sign dilepton events is denoted "OS'', background from nonprompt leptons is denoted "NP'', while other backgrounds modeled from simulation are denoted "MC''. For signals, theoretical uncertainties are labeled as "Shape'' for shape-based searches, and "Accept.'' for counting experiments. Additionally, "CR'' denotes control region and "RMS'' denotes root mean square.

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Table 4:
Signal efficiencies in the single-lepton, same-sign dilepton, and trilepton channels, split into the six possible final states of both $ {{\mathrm {T}} {\overline {\mathrm {T}}}} $ and $ {{\mathrm {B}} {\overline {\mathrm {B}}}} $ production, for three mass points. Efficiencies, stated in percent, are calculated with respect to the expected number of events in the corresponding decay mode, before any selection. The most sensitive decay modes for each channel are noted in bold. The efficiency for bWbW events in the same-sign dilepton and trilepton channels is negligible, as is the efficiency for bZbZ events in the same-sign dilepton channel.

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Table 5:
Numbers of predicted and observed events for signal region categories of the single-lepton channel before the fit to data. Uncertainties include both statistical and systematic components.

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Table 6:
Numbers of predicted and observed events for lepton flavor categories in the same-sign dilepton channel before the fit to data. Uncertainties include both statistical and systematic components.

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Table 7:
Numbers of predicted and observed events for lepton flavor categories in the trilepton channel before the fit to data. Uncertainties include both statistical and systematic components.
Summary
A search has been presented for pair-produced vector-like T and B quarks in a data sample of proton-proton collisions recorded during 2016 by the CMS experiment, and corresponding to an integrated luminosity of 35.9 fb$^{-1}$. The search is performed in channels with one lepton, two same-sign leptons, or at least three leptons in the final state and makes use of techniques to identify Lorentz-boosted hadronically decaying W and Higgs bosons. Combining these channels, we exclude T (B) quarks at 95% confidence level with masses below 1200 (1170) GeV in the singlet branching fraction scenario and 1280 (940) GeV in the doublet branching fraction scenario. For other branching fraction scenarios this search excludes T (B) quark masses below 1140-1300 GeV (910-1240 GeV). This represents an improvement in sensitivity of typically 200-600 GeV, compared to previous CMS results. These results are the strongest exclusion limits to date for T quarks with $\mathcal{B}(\mathrm{t}\mathrm{Z})$ greater than ${\approx}$0.5 and for B quarks with $\mathcal{B}(\mathrm{t}\mathrm{W})$ less than ${\approx}$0.6.
References
1 ATLAS Collaboration Observation of a new particle in the search for the standard model Higgs boson with the ATLAS detector at the LHC PLB 716 (2012) 1 1207.7214
2 CMS Collaboration Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC PLB 716 (2012) 30 CMS-HIG-12-028
1207.7235
3 CMS Collaboration Observation of a new boson with mass near 125 GeV in pp collisions at $ \sqrt{s} = $ 7 and 8 TeV JHEP 06 (2013) 081 CMS-HIG-12-036
1303.4571
4 M. Perelstein, M. E. Peskin, and A. Pierce Top quarks and electroweak symmetry breaking in little Higgs models PRD 69 (2004) 075002 hep-ph/0310039
5 O. Matsedonskyi, G. Panico, and A. Wulzer Light top partners for a light composite Higgs JHEP 01 (2013) 164 1204.6333
6 R. Contino, L. Da Rold, and A. Pomarol Light custodians in natural composite Higgs models PRD 75 (2007) 055014 hep-ph/0612048
7 R. Contino, T. Kramer, M. Son, and R. Sundrum Warped/composite phenomenology simplified JHEP 05 (2007) 074 hep-ph/0612180
8 D. B. Kaplan Flavor at SSC energies: A new mechanism for dynamically generated fermion masses NPB 365 (1991) 259
9 M. J. Dugan, H. Georgi, and D. B. Kaplan Anatomy of a composite higgs model NPB 254 (1985) 299
10 J. A. Aguilar-Saavedra Mixing with vector-like quarks: constraints and expectations EPJ Web Conf. 60 (2013) 16012 1306.4432
11 F. del Aguila, J. A. Aguilar-Saavedra, and R. Miquel Constraints on top couplings in models with exotic quarks PRL 82 (1999) 1628 hep-ph/9808400
12 ALEPH, DELPHI, L3, and OPAL Collaborations Electroweak Measurements in Electron-Positron Collisions at W-Boson-Pair Energies at LEP PR 532 (2013) 119 1302.3415
13 O. Eberhardt et al. Impact of a Higgs boson at a mass of 126 GeV on the standard model with three and four fermion generations PRL 109 (2012) 241802 1209.1101
14 A. Djouadi and A. Lenz Sealing the fate of a fourth generation of fermions PLB 715 (2012) 310 1204.1252
15 CMS Collaboration Searches for Higgs bosons in pp collisions at $ \sqrt{s}= $ 7 and 8 TeV in the context of four-generation and fermiophobic models PLB 725 (2013) 36 CMS-HIG-12-013
1302.1764
16 J. A. Aguilar-Saavedra, R. Benbrik, S. Heinemeyer, and M. P\'erez-Victoria Handbook of vectorlike quarks: Mixing and single production PRD 88 (2013) 094010 1306.0572
17 A. De Simone, O. Matsedonskyi, R. Rattazzi, and A. Wulzer A first top partner hunter's guide JHEP 04 (2013) 1 1211.5663
18 F. del Aguila, L. Ametller, G. L. Kane, and J. Vidal Vector-like fermion and standard Higgs production at hadron colliders NPB 334 (1990) 1
19 CMS Collaboration Search for a vector-like quark with charge 2/3 in t + Z events from pp collisions at $ \sqrt{s}= $ 7 TeV PRL 107 (2011) 271802 CMS-EXO-11-005
1109.4985
20 CMS Collaboration Search for pair produced fourth-generation up-type quarks in pp collisions at $ \sqrt{s}= $ 7 TeV with a lepton in the final state PLB 718 (2012) 307 CMS-EXO-11-099
1209.0471
21 ATLAS Collaboration Search for pair production of a new quark that decays to a Z boson and a bottom quark with the ATLAS detector PRL 109 (2012) 071801 1204.1265
22 CMS Collaboration Search for vector-like charge 2/3 T quarks in proton-proton collisions at $ \sqrt{s} = $ 8 TeV PRD 92 (2016) 012003 CMS-B2G-13-005
1509.04177
23 CMS Collaboration Inclusive search for a vector-like T quark with charge $ \frac{2}{3} $ in pp collisions at $ \sqrt{s} = $ 8 TeV PLB 729 (2014) 149 CMS-B2G-12-015
1311.7667
24 ATLAS Collaboration Search for pair production of a new heavy quark that decays into a $ W $ boson and a light quark in $ pp $ collisions at $ \sqrt{s} = $ 8 TeV with the ATLAS detector PRD 92 (2015) 112007 1509.04261
25 ATLAS Collaboration Search for production of vector-like quark pairs and of four top quarks in the lepton-plus-jets final state in $ pp $ collisions at $ \sqrt{s}= $ 8 TeV with the ATLAS detector JHEP 08 (2015) 105 1505.04306
26 ATLAS Collaboration Search for pair production of vector-like top quarks in events with one lepton, jets, and missing transverse momentum in $ \sqrt{s}=13 TeV pp $ collisions with the ATLAS detector JHEP 08 (2017) 052 1705.10751
27 ATLAS Collaboration Search for pair production of heavy vector-like quarks decaying to high-p$ _{T} $ W bosons and b quarks in the lepton-plus-jets final state in pp collisions at $ \sqrt{s}= $ 13 TeV with the ATLAS detector JHEP 10 (2017) 141 1707.03347
28 CMS Collaboration Search for pair production of vector-like T and B quarks in single-lepton final states using boosted jet substructure in proton-proton collisions at $ \sqrt{s}= $ 13 TeV JHEP 11 (2017) 085 CMS-B2G-16-024
1706.03408
29 CMS Collaboration Search for pair production of vector-like quarks in the bW$ \overline{\mathrm{b}} $W channel from proton-proton collisions at $ \sqrt{s} = $ 13 TeV PLB 779 (2018) 82 CMS-B2G-17-003
1710.01539
30 ATLAS Collaboration Search for pair production of up-type vector-like quarks and for four-top-quark events in final states with multiple $ b $-jets with the ATLAS detector Submitted to \it JHEP 1803.09678
31 CMS Collaboration The CMS experiment at the CERN LHC JINST 3 (2008) S08004 CMS-00-001
32 CMS Collaboration Particle-flow reconstruction and global event description with the CMS detector JINST 12 (2017) P10003 CMS-PRF-14-001
1706.04965
33 M. Cacciari, G. P. Salam, and G. Soyez The anti-$ {k_{\mathrm{T}}} $ jet clustering algorithm JHEP 04 (2008) 063 0802.1189
34 M. Cacciari, G. P. Salam, and G. Soyez FastJet user manual EPJC 72 (2012) 1896 1111.6097
35 M. Cacciari, G. P. Salam, and G. Soyez The catchment area of jets JHEP 04 (2008) 005 0802.1188
36 CMS Collaboration Determination of jet energy calibration and transverse momentum resolution in CMS JINST 6 (2011) P11002 CMS-JME-10-011
1107.4277
37 CMS Collaboration Jet algorithms performance in 13 TeV data CMS-PAS-JME-16-003 CMS-PAS-JME-16-003
38 CMS Collaboration The CMS trigger system JINST 12 (2017) P01020 CMS-TRG-12-001
1609.02366
39 NNPDF Collaboration Parton distributions for the LHC Run II JHEP 04 (2015) 040 1410.8849
40 P. Nason A new method for combining NLO QCD with shower Monte Carlo algorithms JHEP 11 (2004) 040 hep-ph/0409146
41 S. Frixione, P. Nason, and C. Oleari Matching NLO QCD computations with Parton Shower simulations: the POWHEG method JHEP 11 (2007) 070 0709.2092
42 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
43 S. Frixione, P. Nason, and G. Ridolfi A positive-weight next-to-leading-order Monte Carlo for heavy flavour hadroproduction JHEP 09 (2007) 126 0707.3088
44 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
45 R. Frederix and S. Frixione Merging meets matching in MC@NLO JHEP 12 (2012) 061 1209.6215
46 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
47 T. Sjostrand, S. Mrenna, and P. Skands PYTHIA 6.4 physics and manual JHEP 05 (2006) 026 hep-ph/0603175
48 T. Sjostrand et al. An introduction to PYTHIA 8.2 CPC 191 (2015) 159 1410.3012
49 CMS Collaboration Investigations of the impact of the parton shower tuning in Pythia 8 in the modelling of $ \mathrm{t\overline{t}} $ at $ \sqrt{s}= $ 8 and 13 TeV CMS-PAS-TOP-16-021 CMS-PAS-TOP-16-021
50 CMS Collaboration Event generator tunes obtained from underlying event and multiparton scattering measurements EPJC 76 (2016) 155 CMS-GEN-14-001
1512.00815
51 GEANT4 Collaboration GEANT4---a simulation toolkit NIMA 506 (2003) 250
52 M. Czakon and A. Mitov Top++: A Program for the calculation of the top-pair cross-section at hadron colliders CPC 185 (2014) 2930 1112.5675
53 M. Czakon, P. Fiedler, and A. Mitov Total top-quark pair-production cross section at hadron colliders through $ \mathcal{O}(\alpha^{4}_{S}) $ PRL 110 (2013) 252004 1303.6254
54 M. Czakon and A. Mitov NNLO corrections to top pair production at hadron colliders: the quark-gluon reaction JHEP 01 (2013) 080 1210.6832
55 M. Czakon and A. Mitov NNLO corrections to top-pair production at hadron colliders: the all-fermionic scattering channels JHEP 12 (2012) 054 1207.0236
56 P. Barnreuther, M. Czakon, and A. Mitov Percent level precision physics at the Tevatron: first genuine NNLO QCD corrections to $ q \bar{q} \to t \bar{t} + X $ PRL 109 (2012) 132001 1204.5201
57 M. Cacciari et al. Top-pair production at hadron colliders with next-to-next-to-leading logarithmic soft-gluon resummation PLB 710 (2012) 612 1111.5869
58 CMS Collaboration Description and performance of track and primary-vertex reconstruction with the CMS tracker JINST 9 (2014) P10009 CMS-TRK-11-001
1405.6569
59 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
60 CMS Collaboration Performance of CMS muon reconstruction in $ pp $ collision events at $ \sqrt{s} = $ 7 TeV JINST 7 (2012) P10002 CMS-MUO-10-004
1206.4071
61 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
62 J. Thaler and K. Van Tilburg Identifying boosted objects with N-subjettiness JHEP 03 (2011) 015 1011.2268
63 S. D. Ellis, C. K. Vermilion, and J. R. Walsh Techniques for improved heavy particle searches with jet substructure PRD 80 (2009) 051501 0903.5081
64 A. J. Larkoski, S. Marzani, G. Soyez, and J. Thaler Soft drop JHEP 05 (2014) 146 1402.2657
65 M. Dasgupta, A. Fregoso, S. Marzani, and G. P. Salam Towards an understanding of jet substructure JHEP 09 (2013) 029 1307.0007
66 CMS Collaboration Measurement of differential cross sections for top quark pair production using the lepton+jets final state in proton-proton collisions at 13 TeV PRD 95 (2017) 092001 CMS-TOP-16-008
1610.04191
67 CMS Collaboration Search for electroweak production of a vector-like quark decaying to a top quark and a Higgs boson using boosted topologies in fully hadronic final states JHEP 04 (2017) 136 CMS-B2G-16-005
1612.05336
68 CMS Collaboration Search for single production of vector-like quarks decaying into a b quark and a W boson in proton-proton collisions at $ \sqrt s = $ 13 TeV PLB 772 (2017) 634 CMS-B2G-16-006
1701.08328
69 CMS Collaboration Search for new physics with same-sign isolated dilepton events with jets and missing transverse energy at the LHC JHEP 06 (2011) 077 CMS-SUS-10-004
1104.3168
70 CMS Collaboration CMS luminosity measurement for the 2016 data taking period CMS-PAS-LUM-17-001 CMS-PAS-LUM-17-001
71 CMS Collaboration Measurement of the $ {\mathrm{W}}^{+}\mathrm{W}^{-} $ cross section in pp collisions at $ \sqrt{s}= $ 8 TeV and limits on anomalous gauge couplings EPJC 76 (2016) 401 CMS-SMP-14-016
1507.03268
72 CMS Collaboration Measurement of the WZ production cross section in pp collisions at $ \sqrt{s} = $ 13 TeV PLB 766 (2017) 268 CMS-SMP-16-002
1607.06943
73 CMS Collaboration Measurement of the ZZ production cross section and $ \mathrm{Z}\to\ell^+\ell^-\ell'^+\ell'^- $ branching fraction in pp collisions at $ \sqrt{s}= $ 13 TeV PLB 763 (2016) 280 CMS-SMP-16-001
1607.08834
74 CMS Collaboration Measurement of the inelastic proton-proton cross section at $ \sqrt{s}= $ 13 TeV Submitted to \it JHEP CMS-FSQ-15-005
1802.02613
75 J. Ott Theta--A framework for template-based modeling and inference 2010 \url http://www-ekp.physik.uni-karlsruhe.de/\ ott/theta/theta-auto
76 Particle Data Group, C. Patrignani et al. Review of particle physics CPC 40 (2016) 100001
77 R. J. Barlow and C. Beeston Fitting using finite Monte Carlo samples CPC 77 (1993) 219
78 J. S. Conway Incorporating nuisance parameters in likelihoods for multisource spectra in Proceedings, PHYSTAT 2011 Workshop on Statistical Issues Related to Discovery Claims in Search Experiments and Unfolding, address = CERN,Geneva, Switzerland, month = January, p. 115 2011 1103.0354
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