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| CMS-PAS-B2G-24-016 | ||
| Search for pair-produced vector-like top quarks decaying to Lorentz-boosted topquarks and scalar bosons in proton-proton collisions at $ \sqrt{s}= $ 13 TeV | ||
| CMS Collaboration | ||
| 2026-05-18 | ||
| Abstract: The first search for pair-produced vector-like top quarks, T, decaying to a new scalar boson $ \phi $ and a standard model (SM) top quark is presented. The search targets events containing a photon pair originating from the decay of one of the scalar bosons, accompanied by all-hadronic decays of the SM top quark pair. The analysis is optimized for boosted top quark signatures in which the decay products of the top quarks are reconstructed as large-radius jets. The search is based on proton-proton collision data at a center-of-mass energy of $ \sqrt{s}= $ 13 TeV, collected by the CMS experiment at the CERN LHC during 2016, 2017, and 2018, corresponding to an integrated luminosity of 138 fb$ ^{-1} $. The search is performed in the two-dimensional $ (m_{\mathrm{T}}, m_{\phi}) $ plane. No significant deviation from the standard model prediction is observed. Assuming a branching fraction of 100$ % $ for $ \phi \to \gamma\gamma $, upper limits at 95$ % $ confidence level are set on the $ \mathrm{T}\bar{\mathrm{T}} $ production cross section. Vector-like top quark masses below 1.39 TeV are excluded. | ||
| Links: CDS record (PDF) ; CADI line (restricted) ; | ||
| Figures | |
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Figure 1:
A representative leading order Feynman diagram for the pair production of vector-like top quarks $ {\mathrm{T}} $ with subsequent $ {\mathrm{T}} \to \phi\mathrm{t} $ decays. |
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Figure 2:
Distribution of reconstructed {\HepParticleT} candidates in the $ m^\mathrm{reco}_{{\mathrm{T}} } $--$ m^\mathrm{reco}_{\phi} $ plane for data (top) and simulated $ \mathrm{t}\overline{\mathrm{t}} $ events (bottom), shown for the SR (left) and CR (right). |
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Figure 2-a:
Distribution of reconstructed {\HepParticleT} candidates in the $ m^\mathrm{reco}_{{\mathrm{T}} } $--$ m^\mathrm{reco}_{\phi} $ plane for data (top) and simulated $ \mathrm{t}\overline{\mathrm{t}} $ events (bottom), shown for the SR (left) and CR (right). |
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Figure 2-b:
Distribution of reconstructed {\HepParticleT} candidates in the $ m^\mathrm{reco}_{{\mathrm{T}} } $--$ m^\mathrm{reco}_{\phi} $ plane for data (top) and simulated $ \mathrm{t}\overline{\mathrm{t}} $ events (bottom), shown for the SR (left) and CR (right). |
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Figure 2-c:
Distribution of reconstructed {\HepParticleT} candidates in the $ m^\mathrm{reco}_{{\mathrm{T}} } $--$ m^\mathrm{reco}_{\phi} $ plane for data (top) and simulated $ \mathrm{t}\overline{\mathrm{t}} $ events (bottom), shown for the SR (left) and CR (right). |
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Figure 2-d:
Distribution of reconstructed {\HepParticleT} candidates in the $ m^\mathrm{reco}_{{\mathrm{T}} } $--$ m^\mathrm{reco}_{\phi} $ plane for data (top) and simulated $ \mathrm{t}\overline{\mathrm{t}} $ events (bottom), shown for the SR (left) and CR (right). |
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Figure 3:
Comparison of data and the postfit background prediction from the background-only fit in the VR. The VR-CR (left) and VR-SR (right) regions are shown. The distributions are projected onto $ m^\mathrm{reco}_{{\mathrm{T}} } $ in three intervals of $ m^\mathrm{reco}_{\phi} $: 25 $ < m^\mathrm{reco}_{\phi} < $ 75 GeV (top), 75 $ < m^\mathrm{reco}_{\phi} < $ 325 GeV (middle), and 325 $ < m^\mathrm{reco}_{\phi} < $ 625 GeV (bottom). The $ \mathrm{t}\overline{\mathrm{t}} $ component scaled by the transfer function is shown in red and the $ \mathrm{W}/\mathrm{Z} $+jets contribution in green. Signal distributions for the mass hypotheses $ m_{{\mathrm{T}} }= $ 1200 GeV, $ m_{\phi}= $ 200 GeV and $ m_{{\mathrm{T}} }= $ 900 GeV, $ m_{\phi}= $ 100 GeV are overlaid as thin lines. The lower panels show the difference between the data and the background prediction. |
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Figure 3-a:
Comparison of data and the postfit background prediction from the background-only fit in the VR. The VR-CR (left) and VR-SR (right) regions are shown. The distributions are projected onto $ m^\mathrm{reco}_{{\mathrm{T}} } $ in three intervals of $ m^\mathrm{reco}_{\phi} $: 25 $ < m^\mathrm{reco}_{\phi} < $ 75 GeV (top), 75 $ < m^\mathrm{reco}_{\phi} < $ 325 GeV (middle), and 325 $ < m^\mathrm{reco}_{\phi} < $ 625 GeV (bottom). The $ \mathrm{t}\overline{\mathrm{t}} $ component scaled by the transfer function is shown in red and the $ \mathrm{W}/\mathrm{Z} $+jets contribution in green. Signal distributions for the mass hypotheses $ m_{{\mathrm{T}} }= $ 1200 GeV, $ m_{\phi}= $ 200 GeV and $ m_{{\mathrm{T}} }= $ 900 GeV, $ m_{\phi}= $ 100 GeV are overlaid as thin lines. The lower panels show the difference between the data and the background prediction. |
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Figure 3-b:
Comparison of data and the postfit background prediction from the background-only fit in the VR. The VR-CR (left) and VR-SR (right) regions are shown. The distributions are projected onto $ m^\mathrm{reco}_{{\mathrm{T}} } $ in three intervals of $ m^\mathrm{reco}_{\phi} $: 25 $ < m^\mathrm{reco}_{\phi} < $ 75 GeV (top), 75 $ < m^\mathrm{reco}_{\phi} < $ 325 GeV (middle), and 325 $ < m^\mathrm{reco}_{\phi} < $ 625 GeV (bottom). The $ \mathrm{t}\overline{\mathrm{t}} $ component scaled by the transfer function is shown in red and the $ \mathrm{W}/\mathrm{Z} $+jets contribution in green. Signal distributions for the mass hypotheses $ m_{{\mathrm{T}} }= $ 1200 GeV, $ m_{\phi}= $ 200 GeV and $ m_{{\mathrm{T}} }= $ 900 GeV, $ m_{\phi}= $ 100 GeV are overlaid as thin lines. The lower panels show the difference between the data and the background prediction. |
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Figure 3-c:
Comparison of data and the postfit background prediction from the background-only fit in the VR. The VR-CR (left) and VR-SR (right) regions are shown. The distributions are projected onto $ m^\mathrm{reco}_{{\mathrm{T}} } $ in three intervals of $ m^\mathrm{reco}_{\phi} $: 25 $ < m^\mathrm{reco}_{\phi} < $ 75 GeV (top), 75 $ < m^\mathrm{reco}_{\phi} < $ 325 GeV (middle), and 325 $ < m^\mathrm{reco}_{\phi} < $ 625 GeV (bottom). The $ \mathrm{t}\overline{\mathrm{t}} $ component scaled by the transfer function is shown in red and the $ \mathrm{W}/\mathrm{Z} $+jets contribution in green. Signal distributions for the mass hypotheses $ m_{{\mathrm{T}} }= $ 1200 GeV, $ m_{\phi}= $ 200 GeV and $ m_{{\mathrm{T}} }= $ 900 GeV, $ m_{\phi}= $ 100 GeV are overlaid as thin lines. The lower panels show the difference between the data and the background prediction. |
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Figure 3-d:
Comparison of data and the postfit background prediction from the background-only fit in the VR. The VR-CR (left) and VR-SR (right) regions are shown. The distributions are projected onto $ m^\mathrm{reco}_{{\mathrm{T}} } $ in three intervals of $ m^\mathrm{reco}_{\phi} $: 25 $ < m^\mathrm{reco}_{\phi} < $ 75 GeV (top), 75 $ < m^\mathrm{reco}_{\phi} < $ 325 GeV (middle), and 325 $ < m^\mathrm{reco}_{\phi} < $ 625 GeV (bottom). The $ \mathrm{t}\overline{\mathrm{t}} $ component scaled by the transfer function is shown in red and the $ \mathrm{W}/\mathrm{Z} $+jets contribution in green. Signal distributions for the mass hypotheses $ m_{{\mathrm{T}} }= $ 1200 GeV, $ m_{\phi}= $ 200 GeV and $ m_{{\mathrm{T}} }= $ 900 GeV, $ m_{\phi}= $ 100 GeV are overlaid as thin lines. The lower panels show the difference between the data and the background prediction. |
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Figure 3-e:
Comparison of data and the postfit background prediction from the background-only fit in the VR. The VR-CR (left) and VR-SR (right) regions are shown. The distributions are projected onto $ m^\mathrm{reco}_{{\mathrm{T}} } $ in three intervals of $ m^\mathrm{reco}_{\phi} $: 25 $ < m^\mathrm{reco}_{\phi} < $ 75 GeV (top), 75 $ < m^\mathrm{reco}_{\phi} < $ 325 GeV (middle), and 325 $ < m^\mathrm{reco}_{\phi} < $ 625 GeV (bottom). The $ \mathrm{t}\overline{\mathrm{t}} $ component scaled by the transfer function is shown in red and the $ \mathrm{W}/\mathrm{Z} $+jets contribution in green. Signal distributions for the mass hypotheses $ m_{{\mathrm{T}} }= $ 1200 GeV, $ m_{\phi}= $ 200 GeV and $ m_{{\mathrm{T}} }= $ 900 GeV, $ m_{\phi}= $ 100 GeV are overlaid as thin lines. The lower panels show the difference between the data and the background prediction. |
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Figure 3-f:
Comparison of data and the postfit background prediction from the background-only fit in the VR. The VR-CR (left) and VR-SR (right) regions are shown. The distributions are projected onto $ m^\mathrm{reco}_{{\mathrm{T}} } $ in three intervals of $ m^\mathrm{reco}_{\phi} $: 25 $ < m^\mathrm{reco}_{\phi} < $ 75 GeV (top), 75 $ < m^\mathrm{reco}_{\phi} < $ 325 GeV (middle), and 325 $ < m^\mathrm{reco}_{\phi} < $ 625 GeV (bottom). The $ \mathrm{t}\overline{\mathrm{t}} $ component scaled by the transfer function is shown in red and the $ \mathrm{W}/\mathrm{Z} $+jets contribution in green. Signal distributions for the mass hypotheses $ m_{{\mathrm{T}} }= $ 1200 GeV, $ m_{\phi}= $ 200 GeV and $ m_{{\mathrm{T}} }= $ 900 GeV, $ m_{\phi}= $ 100 GeV are overlaid as thin lines. The lower panels show the difference between the data and the background prediction. |
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Figure 4:
Comparison of data and the postfit background prediction from the background-only fit in the VR. The VR-CR (left) and VR-SR (right) regions are shown. The distributions are projected onto $ m^\mathrm{reco}_{\phi} $ in three intervals of $ m^\mathrm{reco}_{{\mathrm{T}} } $: 625 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 825 GeV (top), 825 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 1125 GeV (middle), and 1125 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 1525 GeV (bottom). The $ \mathrm{t}\overline{\mathrm{t}} $ component scaled by the transfer function is shown in red and the $ \mathrm{W}/\mathrm{Z} $+jets contribution in green. Signal distributions for the mass hypotheses $ m_{{\mathrm{T}} }= $ 1200 GeV, $ m_{\phi}= $ 200 GeV and $ m_{{\mathrm{T}} }= $ 900 GeV, $ m_{\phi}= $ 100 GeV are overlaid as thin lines. The lower panels show the difference between the data and the background prediction. |
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Figure 4-a:
Comparison of data and the postfit background prediction from the background-only fit in the VR. The VR-CR (left) and VR-SR (right) regions are shown. The distributions are projected onto $ m^\mathrm{reco}_{\phi} $ in three intervals of $ m^\mathrm{reco}_{{\mathrm{T}} } $: 625 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 825 GeV (top), 825 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 1125 GeV (middle), and 1125 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 1525 GeV (bottom). The $ \mathrm{t}\overline{\mathrm{t}} $ component scaled by the transfer function is shown in red and the $ \mathrm{W}/\mathrm{Z} $+jets contribution in green. Signal distributions for the mass hypotheses $ m_{{\mathrm{T}} }= $ 1200 GeV, $ m_{\phi}= $ 200 GeV and $ m_{{\mathrm{T}} }= $ 900 GeV, $ m_{\phi}= $ 100 GeV are overlaid as thin lines. The lower panels show the difference between the data and the background prediction. |
png pdf |
Figure 4-b:
Comparison of data and the postfit background prediction from the background-only fit in the VR. The VR-CR (left) and VR-SR (right) regions are shown. The distributions are projected onto $ m^\mathrm{reco}_{\phi} $ in three intervals of $ m^\mathrm{reco}_{{\mathrm{T}} } $: 625 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 825 GeV (top), 825 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 1125 GeV (middle), and 1125 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 1525 GeV (bottom). The $ \mathrm{t}\overline{\mathrm{t}} $ component scaled by the transfer function is shown in red and the $ \mathrm{W}/\mathrm{Z} $+jets contribution in green. Signal distributions for the mass hypotheses $ m_{{\mathrm{T}} }= $ 1200 GeV, $ m_{\phi}= $ 200 GeV and $ m_{{\mathrm{T}} }= $ 900 GeV, $ m_{\phi}= $ 100 GeV are overlaid as thin lines. The lower panels show the difference between the data and the background prediction. |
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Figure 4-c:
Comparison of data and the postfit background prediction from the background-only fit in the VR. The VR-CR (left) and VR-SR (right) regions are shown. The distributions are projected onto $ m^\mathrm{reco}_{\phi} $ in three intervals of $ m^\mathrm{reco}_{{\mathrm{T}} } $: 625 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 825 GeV (top), 825 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 1125 GeV (middle), and 1125 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 1525 GeV (bottom). The $ \mathrm{t}\overline{\mathrm{t}} $ component scaled by the transfer function is shown in red and the $ \mathrm{W}/\mathrm{Z} $+jets contribution in green. Signal distributions for the mass hypotheses $ m_{{\mathrm{T}} }= $ 1200 GeV, $ m_{\phi}= $ 200 GeV and $ m_{{\mathrm{T}} }= $ 900 GeV, $ m_{\phi}= $ 100 GeV are overlaid as thin lines. The lower panels show the difference between the data and the background prediction. |
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Figure 4-d:
Comparison of data and the postfit background prediction from the background-only fit in the VR. The VR-CR (left) and VR-SR (right) regions are shown. The distributions are projected onto $ m^\mathrm{reco}_{\phi} $ in three intervals of $ m^\mathrm{reco}_{{\mathrm{T}} } $: 625 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 825 GeV (top), 825 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 1125 GeV (middle), and 1125 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 1525 GeV (bottom). The $ \mathrm{t}\overline{\mathrm{t}} $ component scaled by the transfer function is shown in red and the $ \mathrm{W}/\mathrm{Z} $+jets contribution in green. Signal distributions for the mass hypotheses $ m_{{\mathrm{T}} }= $ 1200 GeV, $ m_{\phi}= $ 200 GeV and $ m_{{\mathrm{T}} }= $ 900 GeV, $ m_{\phi}= $ 100 GeV are overlaid as thin lines. The lower panels show the difference between the data and the background prediction. |
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Figure 4-e:
Comparison of data and the postfit background prediction from the background-only fit in the VR. The VR-CR (left) and VR-SR (right) regions are shown. The distributions are projected onto $ m^\mathrm{reco}_{\phi} $ in three intervals of $ m^\mathrm{reco}_{{\mathrm{T}} } $: 625 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 825 GeV (top), 825 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 1125 GeV (middle), and 1125 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 1525 GeV (bottom). The $ \mathrm{t}\overline{\mathrm{t}} $ component scaled by the transfer function is shown in red and the $ \mathrm{W}/\mathrm{Z} $+jets contribution in green. Signal distributions for the mass hypotheses $ m_{{\mathrm{T}} }= $ 1200 GeV, $ m_{\phi}= $ 200 GeV and $ m_{{\mathrm{T}} }= $ 900 GeV, $ m_{\phi}= $ 100 GeV are overlaid as thin lines. The lower panels show the difference between the data and the background prediction. |
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Figure 4-f:
Comparison of data and the postfit background prediction from the background-only fit in the VR. The VR-CR (left) and VR-SR (right) regions are shown. The distributions are projected onto $ m^\mathrm{reco}_{\phi} $ in three intervals of $ m^\mathrm{reco}_{{\mathrm{T}} } $: 625 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 825 GeV (top), 825 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 1125 GeV (middle), and 1125 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 1525 GeV (bottom). The $ \mathrm{t}\overline{\mathrm{t}} $ component scaled by the transfer function is shown in red and the $ \mathrm{W}/\mathrm{Z} $+jets contribution in green. Signal distributions for the mass hypotheses $ m_{{\mathrm{T}} }= $ 1200 GeV, $ m_{\phi}= $ 200 GeV and $ m_{{\mathrm{T}} }= $ 900 GeV, $ m_{\phi}= $ 100 GeV are overlaid as thin lines. The lower panels show the difference between the data and the background prediction. |
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Figure 5:
Comparison of the data and the postfit background prediction projected onto $ m^\mathrm{reco}_{{\mathrm{T}} } $ for the signal hypothesis $ m_{{\mathrm{T}} }= $ 900 GeV and $ m_{\phi}= $ 150 GeV. The CR (left) and SR (right) regions are shown. The distributions are shown in three intervals of $ m^\mathrm{reco}_{\phi} $: 25 $ < m^\mathrm{reco}_{\phi} < $ 75 GeV (top), 75 $ < m^\mathrm{reco}_{\phi} < $ 325 GeV (middle), and 325 $ < m^\mathrm{reco}_{\phi} < $ 625 GeV (bottom). The transferred $ \mathrm{t}\overline{\mathrm{t}} $ contribution is shown in red and the $ \mathrm{W}/\mathrm{Z} $+jets contribution in green. Signal distributions are overlaid as thin lines. The lower panels show the difference between the data and the background prediction. |
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Figure 5-a:
Comparison of the data and the postfit background prediction projected onto $ m^\mathrm{reco}_{{\mathrm{T}} } $ for the signal hypothesis $ m_{{\mathrm{T}} }= $ 900 GeV and $ m_{\phi}= $ 150 GeV. The CR (left) and SR (right) regions are shown. The distributions are shown in three intervals of $ m^\mathrm{reco}_{\phi} $: 25 $ < m^\mathrm{reco}_{\phi} < $ 75 GeV (top), 75 $ < m^\mathrm{reco}_{\phi} < $ 325 GeV (middle), and 325 $ < m^\mathrm{reco}_{\phi} < $ 625 GeV (bottom). The transferred $ \mathrm{t}\overline{\mathrm{t}} $ contribution is shown in red and the $ \mathrm{W}/\mathrm{Z} $+jets contribution in green. Signal distributions are overlaid as thin lines. The lower panels show the difference between the data and the background prediction. |
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Figure 5-b:
Comparison of the data and the postfit background prediction projected onto $ m^\mathrm{reco}_{{\mathrm{T}} } $ for the signal hypothesis $ m_{{\mathrm{T}} }= $ 900 GeV and $ m_{\phi}= $ 150 GeV. The CR (left) and SR (right) regions are shown. The distributions are shown in three intervals of $ m^\mathrm{reco}_{\phi} $: 25 $ < m^\mathrm{reco}_{\phi} < $ 75 GeV (top), 75 $ < m^\mathrm{reco}_{\phi} < $ 325 GeV (middle), and 325 $ < m^\mathrm{reco}_{\phi} < $ 625 GeV (bottom). The transferred $ \mathrm{t}\overline{\mathrm{t}} $ contribution is shown in red and the $ \mathrm{W}/\mathrm{Z} $+jets contribution in green. Signal distributions are overlaid as thin lines. The lower panels show the difference between the data and the background prediction. |
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Figure 5-c:
Comparison of the data and the postfit background prediction projected onto $ m^\mathrm{reco}_{{\mathrm{T}} } $ for the signal hypothesis $ m_{{\mathrm{T}} }= $ 900 GeV and $ m_{\phi}= $ 150 GeV. The CR (left) and SR (right) regions are shown. The distributions are shown in three intervals of $ m^\mathrm{reco}_{\phi} $: 25 $ < m^\mathrm{reco}_{\phi} < $ 75 GeV (top), 75 $ < m^\mathrm{reco}_{\phi} < $ 325 GeV (middle), and 325 $ < m^\mathrm{reco}_{\phi} < $ 625 GeV (bottom). The transferred $ \mathrm{t}\overline{\mathrm{t}} $ contribution is shown in red and the $ \mathrm{W}/\mathrm{Z} $+jets contribution in green. Signal distributions are overlaid as thin lines. The lower panels show the difference between the data and the background prediction. |
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Figure 5-d:
Comparison of the data and the postfit background prediction projected onto $ m^\mathrm{reco}_{{\mathrm{T}} } $ for the signal hypothesis $ m_{{\mathrm{T}} }= $ 900 GeV and $ m_{\phi}= $ 150 GeV. The CR (left) and SR (right) regions are shown. The distributions are shown in three intervals of $ m^\mathrm{reco}_{\phi} $: 25 $ < m^\mathrm{reco}_{\phi} < $ 75 GeV (top), 75 $ < m^\mathrm{reco}_{\phi} < $ 325 GeV (middle), and 325 $ < m^\mathrm{reco}_{\phi} < $ 625 GeV (bottom). The transferred $ \mathrm{t}\overline{\mathrm{t}} $ contribution is shown in red and the $ \mathrm{W}/\mathrm{Z} $+jets contribution in green. Signal distributions are overlaid as thin lines. The lower panels show the difference between the data and the background prediction. |
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Figure 5-e:
Comparison of the data and the postfit background prediction projected onto $ m^\mathrm{reco}_{{\mathrm{T}} } $ for the signal hypothesis $ m_{{\mathrm{T}} }= $ 900 GeV and $ m_{\phi}= $ 150 GeV. The CR (left) and SR (right) regions are shown. The distributions are shown in three intervals of $ m^\mathrm{reco}_{\phi} $: 25 $ < m^\mathrm{reco}_{\phi} < $ 75 GeV (top), 75 $ < m^\mathrm{reco}_{\phi} < $ 325 GeV (middle), and 325 $ < m^\mathrm{reco}_{\phi} < $ 625 GeV (bottom). The transferred $ \mathrm{t}\overline{\mathrm{t}} $ contribution is shown in red and the $ \mathrm{W}/\mathrm{Z} $+jets contribution in green. Signal distributions are overlaid as thin lines. The lower panels show the difference between the data and the background prediction. |
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Figure 5-f:
Comparison of the data and the postfit background prediction projected onto $ m^\mathrm{reco}_{{\mathrm{T}} } $ for the signal hypothesis $ m_{{\mathrm{T}} }= $ 900 GeV and $ m_{\phi}= $ 150 GeV. The CR (left) and SR (right) regions are shown. The distributions are shown in three intervals of $ m^\mathrm{reco}_{\phi} $: 25 $ < m^\mathrm{reco}_{\phi} < $ 75 GeV (top), 75 $ < m^\mathrm{reco}_{\phi} < $ 325 GeV (middle), and 325 $ < m^\mathrm{reco}_{\phi} < $ 625 GeV (bottom). The transferred $ \mathrm{t}\overline{\mathrm{t}} $ contribution is shown in red and the $ \mathrm{W}/\mathrm{Z} $+jets contribution in green. Signal distributions are overlaid as thin lines. The lower panels show the difference between the data and the background prediction. |
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Figure 6:
Comparison of the data and the postfit background prediction projected onto $ m^\mathrm{reco}_{\phi} $ for the signal hypothesis $ m_{{\mathrm{T}} }= $ 900 GeV and $ m_{\phi}= $ 150 GeV. The CR (left) and SR (right) regions are shown. The distributions are shown in three intervals of $ m^\mathrm{reco}_{{\mathrm{T}} } $: 625 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 825 GeV (top), 825 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 1125 GeV (middle), and 1125 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 1525 GeV (bottom). The transferred $ \mathrm{t}\overline{\mathrm{t}} $ contribution is shown in red and the $ \mathrm{W}/\mathrm{Z} $+jets contribution in green. Signal distributions are overlaid as thin lines. The lower panels show the difference between the data and the background prediction. |
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Figure 6-a:
Comparison of the data and the postfit background prediction projected onto $ m^\mathrm{reco}_{\phi} $ for the signal hypothesis $ m_{{\mathrm{T}} }= $ 900 GeV and $ m_{\phi}= $ 150 GeV. The CR (left) and SR (right) regions are shown. The distributions are shown in three intervals of $ m^\mathrm{reco}_{{\mathrm{T}} } $: 625 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 825 GeV (top), 825 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 1125 GeV (middle), and 1125 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 1525 GeV (bottom). The transferred $ \mathrm{t}\overline{\mathrm{t}} $ contribution is shown in red and the $ \mathrm{W}/\mathrm{Z} $+jets contribution in green. Signal distributions are overlaid as thin lines. The lower panels show the difference between the data and the background prediction. |
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Figure 6-b:
Comparison of the data and the postfit background prediction projected onto $ m^\mathrm{reco}_{\phi} $ for the signal hypothesis $ m_{{\mathrm{T}} }= $ 900 GeV and $ m_{\phi}= $ 150 GeV. The CR (left) and SR (right) regions are shown. The distributions are shown in three intervals of $ m^\mathrm{reco}_{{\mathrm{T}} } $: 625 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 825 GeV (top), 825 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 1125 GeV (middle), and 1125 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 1525 GeV (bottom). The transferred $ \mathrm{t}\overline{\mathrm{t}} $ contribution is shown in red and the $ \mathrm{W}/\mathrm{Z} $+jets contribution in green. Signal distributions are overlaid as thin lines. The lower panels show the difference between the data and the background prediction. |
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Figure 6-c:
Comparison of the data and the postfit background prediction projected onto $ m^\mathrm{reco}_{\phi} $ for the signal hypothesis $ m_{{\mathrm{T}} }= $ 900 GeV and $ m_{\phi}= $ 150 GeV. The CR (left) and SR (right) regions are shown. The distributions are shown in three intervals of $ m^\mathrm{reco}_{{\mathrm{T}} } $: 625 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 825 GeV (top), 825 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 1125 GeV (middle), and 1125 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 1525 GeV (bottom). The transferred $ \mathrm{t}\overline{\mathrm{t}} $ contribution is shown in red and the $ \mathrm{W}/\mathrm{Z} $+jets contribution in green. Signal distributions are overlaid as thin lines. The lower panels show the difference between the data and the background prediction. |
png pdf |
Figure 6-d:
Comparison of the data and the postfit background prediction projected onto $ m^\mathrm{reco}_{\phi} $ for the signal hypothesis $ m_{{\mathrm{T}} }= $ 900 GeV and $ m_{\phi}= $ 150 GeV. The CR (left) and SR (right) regions are shown. The distributions are shown in three intervals of $ m^\mathrm{reco}_{{\mathrm{T}} } $: 625 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 825 GeV (top), 825 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 1125 GeV (middle), and 1125 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 1525 GeV (bottom). The transferred $ \mathrm{t}\overline{\mathrm{t}} $ contribution is shown in red and the $ \mathrm{W}/\mathrm{Z} $+jets contribution in green. Signal distributions are overlaid as thin lines. The lower panels show the difference between the data and the background prediction. |
png pdf |
Figure 6-e:
Comparison of the data and the postfit background prediction projected onto $ m^\mathrm{reco}_{\phi} $ for the signal hypothesis $ m_{{\mathrm{T}} }= $ 900 GeV and $ m_{\phi}= $ 150 GeV. The CR (left) and SR (right) regions are shown. The distributions are shown in three intervals of $ m^\mathrm{reco}_{{\mathrm{T}} } $: 625 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 825 GeV (top), 825 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 1125 GeV (middle), and 1125 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 1525 GeV (bottom). The transferred $ \mathrm{t}\overline{\mathrm{t}} $ contribution is shown in red and the $ \mathrm{W}/\mathrm{Z} $+jets contribution in green. Signal distributions are overlaid as thin lines. The lower panels show the difference between the data and the background prediction. |
png pdf |
Figure 6-f:
Comparison of the data and the postfit background prediction projected onto $ m^\mathrm{reco}_{\phi} $ for the signal hypothesis $ m_{{\mathrm{T}} }= $ 900 GeV and $ m_{\phi}= $ 150 GeV. The CR (left) and SR (right) regions are shown. The distributions are shown in three intervals of $ m^\mathrm{reco}_{{\mathrm{T}} } $: 625 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 825 GeV (top), 825 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 1125 GeV (middle), and 1125 $ < m^\mathrm{reco}_{{\mathrm{T}} } < $ 1525 GeV (bottom). The transferred $ \mathrm{t}\overline{\mathrm{t}} $ contribution is shown in red and the $ \mathrm{W}/\mathrm{Z} $+jets contribution in green. Signal distributions are overlaid as thin lines. The lower panels show the difference between the data and the background prediction. |
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Figure 7:
Expected (top) and observed (bottom) upper limits on $ \sigma_{{\mathrm{T}} {\mathrm{T}} } \times B({\mathrm{T}} \to \phi \mathrm{t})^2 \times B(\phi \to \gamma\gamma) $ in the $ (m_{{\mathrm{T}} }, m_{\phi}) $ plane. |
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Figure 7-a:
Expected (top) and observed (bottom) upper limits on $ \sigma_{{\mathrm{T}} {\mathrm{T}} } \times B({\mathrm{T}} \to \phi \mathrm{t})^2 \times B(\phi \to \gamma\gamma) $ in the $ (m_{{\mathrm{T}} }, m_{\phi}) $ plane. |
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Figure 7-b:
Expected (top) and observed (bottom) upper limits on $ \sigma_{{\mathrm{T}} {\mathrm{T}} } \times B({\mathrm{T}} \to \phi \mathrm{t})^2 \times B(\phi \to \gamma\gamma) $ in the $ (m_{{\mathrm{T}} }, m_{\phi}) $ plane. |
png pdf |
Figure 8:
Observed (solid) and expected (dashed) upper limits on the $ {\mathrm{T}} {\mathrm{T}} $ production cross section as a function of $ m_{{\mathrm{T}} } $ for different values of $ m_{\phi} $. The first row shows $ m_{\phi}= $ 100 and 150 GeV (left to right), the second row shows $ m_{\phi}= $ 200 and 250 GeV (left to right), and the third row shows $ m_{\phi}= $ 300 GeV. Theoretical cross section times $ \phi $ branching fractions are shown for $ B(\phi \to \gamma\gamma)= $ 1.0 (blue) and 0.004 (magenta). |
png pdf |
Figure 8-a:
Observed (solid) and expected (dashed) upper limits on the $ {\mathrm{T}} {\mathrm{T}} $ production cross section as a function of $ m_{{\mathrm{T}} } $ for different values of $ m_{\phi} $. The first row shows $ m_{\phi}= $ 100 and 150 GeV (left to right), the second row shows $ m_{\phi}= $ 200 and 250 GeV (left to right), and the third row shows $ m_{\phi}= $ 300 GeV. Theoretical cross section times $ \phi $ branching fractions are shown for $ B(\phi \to \gamma\gamma)= $ 1.0 (blue) and 0.004 (magenta). |
png pdf |
Figure 8-b:
Observed (solid) and expected (dashed) upper limits on the $ {\mathrm{T}} {\mathrm{T}} $ production cross section as a function of $ m_{{\mathrm{T}} } $ for different values of $ m_{\phi} $. The first row shows $ m_{\phi}= $ 100 and 150 GeV (left to right), the second row shows $ m_{\phi}= $ 200 and 250 GeV (left to right), and the third row shows $ m_{\phi}= $ 300 GeV. Theoretical cross section times $ \phi $ branching fractions are shown for $ B(\phi \to \gamma\gamma)= $ 1.0 (blue) and 0.004 (magenta). |
png pdf |
Figure 8-c:
Observed (solid) and expected (dashed) upper limits on the $ {\mathrm{T}} {\mathrm{T}} $ production cross section as a function of $ m_{{\mathrm{T}} } $ for different values of $ m_{\phi} $. The first row shows $ m_{\phi}= $ 100 and 150 GeV (left to right), the second row shows $ m_{\phi}= $ 200 and 250 GeV (left to right), and the third row shows $ m_{\phi}= $ 300 GeV. Theoretical cross section times $ \phi $ branching fractions are shown for $ B(\phi \to \gamma\gamma)= $ 1.0 (blue) and 0.004 (magenta). |
png pdf |
Figure 8-d:
Observed (solid) and expected (dashed) upper limits on the $ {\mathrm{T}} {\mathrm{T}} $ production cross section as a function of $ m_{{\mathrm{T}} } $ for different values of $ m_{\phi} $. The first row shows $ m_{\phi}= $ 100 and 150 GeV (left to right), the second row shows $ m_{\phi}= $ 200 and 250 GeV (left to right), and the third row shows $ m_{\phi}= $ 300 GeV. Theoretical cross section times $ \phi $ branching fractions are shown for $ B(\phi \to \gamma\gamma)= $ 1.0 (blue) and 0.004 (magenta). |
png pdf |
Figure 8-e:
Observed (solid) and expected (dashed) upper limits on the $ {\mathrm{T}} {\mathrm{T}} $ production cross section as a function of $ m_{{\mathrm{T}} } $ for different values of $ m_{\phi} $. The first row shows $ m_{\phi}= $ 100 and 150 GeV (left to right), the second row shows $ m_{\phi}= $ 200 and 250 GeV (left to right), and the third row shows $ m_{\phi}= $ 300 GeV. Theoretical cross section times $ \phi $ branching fractions are shown for $ B(\phi \to \gamma\gamma)= $ 1.0 (blue) and 0.004 (magenta). |
| Tables | |
png pdf |
Table 1:
Event selection for the signal and control regions |
png pdf |
Table 2:
Theoretical NNLO cross sections for {\HepParticleT} pair production [48]. |
| Summary |
| A search for the pair production of vector-like top quarks $ {\mathrm{T}} $ in a scenario involving an additional scalar boson is presented. The search uses proton-proton collision data collected by the CMS experiment at the LHC during 2016--2018, corresponding to an integrated luminosity of 138 fb$ ^{-1} $. The analysis considers $ {\mathrm{T}} {\mathrm{T}} $ production, with each $ {\mathrm{T}} $ decaying to a standard model top quark and a scalar boson $ \phi $. The top quarks are required to decay hadronically, and one of the scalar bosons is required to decay to a pair of photons, while the second $ \phi $ boson is treated inclusively. The top quarks are reconstructed as large-radius jets and identified using a ParticleNet discriminant, while a multivariate discriminant is used for photon identification. A data-driven method is used to predict the background in the signal region from the $ \mathrm{t}\overline{\mathrm{t}} $ distribution in a control region via a transfer function. No significant deviation from the background prediction is observed. Assuming a branching fraction $ B(\phi \to \gamma\gamma)=100% $, vector-like top quark masses below 1.39 TeV are excluded. |
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