CMS-PAS-B2G-20-007 | ||
Search for heavy resonances decaying to a pair of boosted Higgs bosons in final states with leptons and a bottom quark-antiquark pair at √s= 13 TeV | ||
CMS Collaboration | ||
July 2021 | ||
Abstract: A search for new heavy resonances decaying to a pair of Higgs bosons in proton-proton collisions at a center-of-mass energy of 13 TeV is presented. Data were collected by the CMS detector at the LHC from 2016 to 2018, corresponding to an integrated luminosity of 138 fb−1. The search considers resonances with a mass between 0.8 and 4.5 TeV using events in which one Higgs boson decays into a bottom quark-antiquark pair and the other decays into final states with either one or two charged leptons. Specifically, these include the single-lepton final state of the HH→bˉbWW∗→bˉbℓνqˉq decay and the dilepton final states of both the HH→bˉbWW∗→bˉbℓνℓν and HH→bˉbττ→bˉbℓννℓνν decays, where ℓ in the final state corresponds to e or μ. The signal is extracted using a two-dimensional maximum likelihood fit of the H→bˉb jet mass and HH invariant mass distributions. No significant excess above the standard model expectation is observed in data. Model-independent exclusion limits are placed on the the product of the cross section and branching fraction (σB) for spin-0 and spin-2 massive bosons decaying to HH. The results are interpreted in the context of radion and bulk graviton production in models with a warped extra spatial dimension. | ||
Links:
CDS record (PDF) ;
CADI line (restricted) ;
These preliminary results are superseded in this paper, JHEP 05 (2022) 005. The superseded preliminary plots can be found here. |
Figures | |
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Figure 1:
Single-lepton channel variables: distributions of important variables are shown for data (points), simulated SM processes (filled histograms), and simulated signal (solid lines). The statistical uncertainty of the simulated sample is shown as the hatched band. Spin-0 signals for mX of 1.0 and 3.0 TeV are displayed. For both signal models, σB(X→HH) is set to 1.0 pb. The bottom panes of each plot show the ratio of the data to the sum of all background processes. |
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Figure 1-a:
Single-lepton channel variables: distributions of important variables are shown for data (points), simulated SM processes (filled histograms), and simulated signal (solid lines). The statistical uncertainty of the simulated sample is shown as the hatched band. Spin-0 signals for mX of 1.0 and 3.0 TeV are displayed. For both signal models, σB(X→HH) is set to 1.0 pb. The bottom panes of each plot show the ratio of the data to the sum of all background processes. |
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Figure 1-b:
Single-lepton channel variables: distributions of important variables are shown for data (points), simulated SM processes (filled histograms), and simulated signal (solid lines). The statistical uncertainty of the simulated sample is shown as the hatched band. Spin-0 signals for mX of 1.0 and 3.0 TeV are displayed. For both signal models, σB(X→HH) is set to 1.0 pb. The bottom panes of each plot show the ratio of the data to the sum of all background processes. |
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Figure 1-c:
Single-lepton channel variables: distributions of important variables are shown for data (points), simulated SM processes (filled histograms), and simulated signal (solid lines). The statistical uncertainty of the simulated sample is shown as the hatched band. Spin-0 signals for mX of 1.0 and 3.0 TeV are displayed. For both signal models, σB(X→HH) is set to 1.0 pb. The bottom panes of each plot show the ratio of the data to the sum of all background processes. |
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Figure 1-d:
Single-lepton channel variables: distributions of important variables are shown for data (points), simulated SM processes (filled histograms), and simulated signal (solid lines). The statistical uncertainty of the simulated sample is shown as the hatched band. Spin-0 signals for mX of 1.0 and 3.0 TeV are displayed. For both signal models, σB(X→HH) is set to 1.0 pb. The bottom panes of each plot show the ratio of the data to the sum of all background processes. |
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Figure 1-e:
Single-lepton channel variables: distributions of important variables are shown for data (points), simulated SM processes (filled histograms), and simulated signal (solid lines). The statistical uncertainty of the simulated sample is shown as the hatched band. Spin-0 signals for mX of 1.0 and 3.0 TeV are displayed. For both signal models, σB(X→HH) is set to 1.0 pb. The bottom panes of each plot show the ratio of the data to the sum of all background processes. |
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Figure 2:
Dilepton channel variables: distributions of important variables are shown for data (points), simulated SM processes (filled histograms), and simulated signal (solid lines). The statistical uncertainty of the simulated sample is shown as the hatched band. Spin-0 signals for mX of 1.0 and 3.0 TeV are displayed. For both signal models, σB(X→HH) is set to 0.1 pb. The bottom panes of each plot show the ratio of the data to the sum of all background processes. |
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Figure 2-a:
Dilepton channel variables: distributions of important variables are shown for data (points), simulated SM processes (filled histograms), and simulated signal (solid lines). The statistical uncertainty of the simulated sample is shown as the hatched band. Spin-0 signals for mX of 1.0 and 3.0 TeV are displayed. For both signal models, σB(X→HH) is set to 0.1 pb. The bottom panes of each plot show the ratio of the data to the sum of all background processes. |
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Figure 2-b:
Dilepton channel variables: distributions of important variables are shown for data (points), simulated SM processes (filled histograms), and simulated signal (solid lines). The statistical uncertainty of the simulated sample is shown as the hatched band. Spin-0 signals for mX of 1.0 and 3.0 TeV are displayed. For both signal models, σB(X→HH) is set to 0.1 pb. The bottom panes of each plot show the ratio of the data to the sum of all background processes. |
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Figure 2-c:
Dilepton channel variables: distributions of important variables are shown for data (points), simulated SM processes (filled histograms), and simulated signal (solid lines). The statistical uncertainty of the simulated sample is shown as the hatched band. Spin-0 signals for mX of 1.0 and 3.0 TeV are displayed. For both signal models, σB(X→HH) is set to 0.1 pb. The bottom panes of each plot show the ratio of the data to the sum of all background processes. |
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Figure 2-d:
Dilepton channel variables: distributions of important variables are shown for data (points), simulated SM processes (filled histograms), and simulated signal (solid lines). The statistical uncertainty of the simulated sample is shown as the hatched band. Spin-0 signals for mX of 1.0 and 3.0 TeV are displayed. For both signal models, σB(X→HH) is set to 0.1 pb. The bottom panes of each plot show the ratio of the data to the sum of all background processes. |
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Figure 2-e:
Dilepton channel variables: distributions of important variables are shown for data (points), simulated SM processes (filled histograms), and simulated signal (solid lines). The statistical uncertainty of the simulated sample is shown as the hatched band. Spin-0 signals for mX of 1.0 and 3.0 TeV are displayed. For both signal models, σB(X→HH) is set to 0.1 pb. The bottom panes of each plot show the ratio of the data to the sum of all background processes. |
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Figure 2-f:
Dilepton channel variables: distributions of important variables are shown for data (points), simulated SM processes (filled histograms), and simulated signal (solid lines). The statistical uncertainty of the simulated sample is shown as the hatched band. Spin-0 signals for mX of 1.0 and 3.0 TeV are displayed. For both signal models, σB(X→HH) is set to 0.1 pb. The bottom panes of each plot show the ratio of the data to the sum of all background processes. |
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Figure 3:
The post-fit model compared to data in the top CR (upper plots) and non-top CR (lower plots), projected into mbˉb (left) and mHH (right). Events from all categories are combined. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty is shown as the hatched band. The bottom panes of each plot show ratio of the data to the fit result. |
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Figure 3-a:
The post-fit model compared to data in the top CR (upper plots) and non-top CR (lower plots), projected into mbˉb (left) and mHH (right). Events from all categories are combined. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty is shown as the hatched band. The bottom panes of each plot show ratio of the data to the fit result. |
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Figure 3-b:
The post-fit model compared to data in the top CR (upper plots) and non-top CR (lower plots), projected into mbˉb (left) and mHH (right). Events from all categories are combined. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty is shown as the hatched band. The bottom panes of each plot show ratio of the data to the fit result. |
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Figure 3-c:
The post-fit model compared to data in the top CR (upper plots) and non-top CR (lower plots), projected into mbˉb (left) and mHH (right). Events from all categories are combined. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty is shown as the hatched band. The bottom panes of each plot show ratio of the data to the fit result. |
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Figure 3-d:
The post-fit model compared to data in the top CR (upper plots) and non-top CR (lower plots), projected into mbˉb (left) and mHH (right). Events from all categories are combined. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty is shown as the hatched band. The bottom panes of each plot show ratio of the data to the fit result. |
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Figure 4:
The fit result compared to data projected into mbˉb for both the single- and dilepton channels. The label for each search category is in the upper left of each plot. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty from the fit is shown as the hatched band. Example spin-0 signal distributions for mX= 1.0 and 3.0 TeV are shown as solid lines, with σB(X→HH) set to 0.2 and 0.1 pb for the SL and DL channels, respectively. The bottom panes show the ratio of the data to the fit result. |
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Figure 4-a:
The fit result compared to data projected into mbˉb for both the single- and dilepton channels. The label for each search category is in the upper left of each plot. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty from the fit is shown as the hatched band. Example spin-0 signal distributions for mX= 1.0 and 3.0 TeV are shown as solid lines, with σB(X→HH) set to 0.2 and 0.1 pb for the SL and DL channels, respectively. The bottom panes show the ratio of the data to the fit result. |
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Figure 4-b:
The fit result compared to data projected into mbˉb for both the single- and dilepton channels. The label for each search category is in the upper left of each plot. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty from the fit is shown as the hatched band. Example spin-0 signal distributions for mX= 1.0 and 3.0 TeV are shown as solid lines, with σB(X→HH) set to 0.2 and 0.1 pb for the SL and DL channels, respectively. The bottom panes show the ratio of the data to the fit result. |
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Figure 4-c:
The fit result compared to data projected into mbˉb for both the single- and dilepton channels. The label for each search category is in the upper left of each plot. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty from the fit is shown as the hatched band. Example spin-0 signal distributions for mX= 1.0 and 3.0 TeV are shown as solid lines, with σB(X→HH) set to 0.2 and 0.1 pb for the SL and DL channels, respectively. The bottom panes show the ratio of the data to the fit result. |
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Figure 4-d:
The fit result compared to data projected into mbˉb for both the single- and dilepton channels. The label for each search category is in the upper left of each plot. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty from the fit is shown as the hatched band. Example spin-0 signal distributions for mX= 1.0 and 3.0 TeV are shown as solid lines, with σB(X→HH) set to 0.2 and 0.1 pb for the SL and DL channels, respectively. The bottom panes show the ratio of the data to the fit result. |
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Figure 4-e:
The fit result compared to data projected into mbˉb for both the single- and dilepton channels. The label for each search category is in the upper left of each plot. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty from the fit is shown as the hatched band. Example spin-0 signal distributions for mX= 1.0 and 3.0 TeV are shown as solid lines, with σB(X→HH) set to 0.2 and 0.1 pb for the SL and DL channels, respectively. The bottom panes show the ratio of the data to the fit result. |
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Figure 4-f:
The fit result compared to data projected into mbˉb for both the single- and dilepton channels. The label for each search category is in the upper left of each plot. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty from the fit is shown as the hatched band. Example spin-0 signal distributions for mX= 1.0 and 3.0 TeV are shown as solid lines, with σB(X→HH) set to 0.2 and 0.1 pb for the SL and DL channels, respectively. The bottom panes show the ratio of the data to the fit result. |
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Figure 4-g:
The fit result compared to data projected into mbˉb for both the single- and dilepton channels. The label for each search category is in the upper left of each plot. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty from the fit is shown as the hatched band. Example spin-0 signal distributions for mX= 1.0 and 3.0 TeV are shown as solid lines, with σB(X→HH) set to 0.2 and 0.1 pb for the SL and DL channels, respectively. The bottom panes show the ratio of the data to the fit result. |
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Figure 4-h:
The fit result compared to data projected into mbˉb for both the single- and dilepton channels. The label for each search category is in the upper left of each plot. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty from the fit is shown as the hatched band. Example spin-0 signal distributions for mX= 1.0 and 3.0 TeV are shown as solid lines, with σB(X→HH) set to 0.2 and 0.1 pb for the SL and DL channels, respectively. The bottom panes show the ratio of the data to the fit result. |
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Figure 4-i:
The fit result compared to data projected into mbˉb for both the single- and dilepton channels. The label for each search category is in the upper left of each plot. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty from the fit is shown as the hatched band. Example spin-0 signal distributions for mX= 1.0 and 3.0 TeV are shown as solid lines, with σB(X→HH) set to 0.2 and 0.1 pb for the SL and DL channels, respectively. The bottom panes show the ratio of the data to the fit result. |
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Figure 4-j:
The fit result compared to data projected into mbˉb for both the single- and dilepton channels. The label for each search category is in the upper left of each plot. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty from the fit is shown as the hatched band. Example spin-0 signal distributions for mX= 1.0 and 3.0 TeV are shown as solid lines, with σB(X→HH) set to 0.2 and 0.1 pb for the SL and DL channels, respectively. The bottom panes show the ratio of the data to the fit result. |
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Figure 4-k:
The fit result compared to data projected into mbˉb for both the single- and dilepton channels. The label for each search category is in the upper left of each plot. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty from the fit is shown as the hatched band. Example spin-0 signal distributions for mX= 1.0 and 3.0 TeV are shown as solid lines, with σB(X→HH) set to 0.2 and 0.1 pb for the SL and DL channels, respectively. The bottom panes show the ratio of the data to the fit result. |
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Figure 4-l:
The fit result compared to data projected into mbˉb for both the single- and dilepton channels. The label for each search category is in the upper left of each plot. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty from the fit is shown as the hatched band. Example spin-0 signal distributions for mX= 1.0 and 3.0 TeV are shown as solid lines, with σB(X→HH) set to 0.2 and 0.1 pb for the SL and DL channels, respectively. The bottom panes show the ratio of the data to the fit result. |
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Figure 5:
The fit result compared to data projected into mHH for both the single- and dilepton channels. The label for each search category is in the upper left of each plot. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty from the fit is shown as the hatched band. Example spin-0 signal distributions for mX= 1.0 and 3.0 TeV are shown as solid lines, with σB(X→HH) set to 0.2 and 0.1 pb for the SL and DL channels, respectively. The bottom panes of each plot show the ratio of the data to the fit result. |
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Figure 5-a:
The fit result compared to data projected into mHH for both the single- and dilepton channels. The label for each search category is in the upper left of each plot. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty from the fit is shown as the hatched band. Example spin-0 signal distributions for mX= 1.0 and 3.0 TeV are shown as solid lines, with σB(X→HH) set to 0.2 and 0.1 pb for the SL and DL channels, respectively. The bottom panes of each plot show the ratio of the data to the fit result. |
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Figure 5-b:
The fit result compared to data projected into mHH for both the single- and dilepton channels. The label for each search category is in the upper left of each plot. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty from the fit is shown as the hatched band. Example spin-0 signal distributions for mX= 1.0 and 3.0 TeV are shown as solid lines, with σB(X→HH) set to 0.2 and 0.1 pb for the SL and DL channels, respectively. The bottom panes of each plot show the ratio of the data to the fit result. |
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Figure 5-c:
The fit result compared to data projected into mHH for both the single- and dilepton channels. The label for each search category is in the upper left of each plot. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty from the fit is shown as the hatched band. Example spin-0 signal distributions for mX= 1.0 and 3.0 TeV are shown as solid lines, with σB(X→HH) set to 0.2 and 0.1 pb for the SL and DL channels, respectively. The bottom panes of each plot show the ratio of the data to the fit result. |
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Figure 5-d:
The fit result compared to data projected into mHH for both the single- and dilepton channels. The label for each search category is in the upper left of each plot. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty from the fit is shown as the hatched band. Example spin-0 signal distributions for mX= 1.0 and 3.0 TeV are shown as solid lines, with σB(X→HH) set to 0.2 and 0.1 pb for the SL and DL channels, respectively. The bottom panes of each plot show the ratio of the data to the fit result. |
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Figure 5-e:
The fit result compared to data projected into mHH for both the single- and dilepton channels. The label for each search category is in the upper left of each plot. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty from the fit is shown as the hatched band. Example spin-0 signal distributions for mX= 1.0 and 3.0 TeV are shown as solid lines, with σB(X→HH) set to 0.2 and 0.1 pb for the SL and DL channels, respectively. The bottom panes of each plot show the ratio of the data to the fit result. |
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Figure 5-f:
The fit result compared to data projected into mHH for both the single- and dilepton channels. The label for each search category is in the upper left of each plot. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty from the fit is shown as the hatched band. Example spin-0 signal distributions for mX= 1.0 and 3.0 TeV are shown as solid lines, with σB(X→HH) set to 0.2 and 0.1 pb for the SL and DL channels, respectively. The bottom panes of each plot show the ratio of the data to the fit result. |
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Figure 5-g:
The fit result compared to data projected into mHH for both the single- and dilepton channels. The label for each search category is in the upper left of each plot. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty from the fit is shown as the hatched band. Example spin-0 signal distributions for mX= 1.0 and 3.0 TeV are shown as solid lines, with σB(X→HH) set to 0.2 and 0.1 pb for the SL and DL channels, respectively. The bottom panes of each plot show the ratio of the data to the fit result. |
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Figure 5-h:
The fit result compared to data projected into mHH for both the single- and dilepton channels. The label for each search category is in the upper left of each plot. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty from the fit is shown as the hatched band. Example spin-0 signal distributions for mX= 1.0 and 3.0 TeV are shown as solid lines, with σB(X→HH) set to 0.2 and 0.1 pb for the SL and DL channels, respectively. The bottom panes of each plot show the ratio of the data to the fit result. |
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Figure 5-i:
The fit result compared to data projected into mHH for both the single- and dilepton channels. The label for each search category is in the upper left of each plot. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty from the fit is shown as the hatched band. Example spin-0 signal distributions for mX= 1.0 and 3.0 TeV are shown as solid lines, with σB(X→HH) set to 0.2 and 0.1 pb for the SL and DL channels, respectively. The bottom panes of each plot show the ratio of the data to the fit result. |
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Figure 5-j:
The fit result compared to data projected into mHH for both the single- and dilepton channels. The label for each search category is in the upper left of each plot. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty from the fit is shown as the hatched band. Example spin-0 signal distributions for mX= 1.0 and 3.0 TeV are shown as solid lines, with σB(X→HH) set to 0.2 and 0.1 pb for the SL and DL channels, respectively. The bottom panes of each plot show the ratio of the data to the fit result. |
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Figure 5-k:
The fit result compared to data projected into mHH for both the single- and dilepton channels. The label for each search category is in the upper left of each plot. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty from the fit is shown as the hatched band. Example spin-0 signal distributions for mX= 1.0 and 3.0 TeV are shown as solid lines, with σB(X→HH) set to 0.2 and 0.1 pb for the SL and DL channels, respectively. The bottom panes of each plot show the ratio of the data to the fit result. |
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Figure 5-l:
The fit result compared to data projected into mHH for both the single- and dilepton channels. The label for each search category is in the upper left of each plot. The fit result is the filled histogram, with the different colors indicating different background categories. The background shape uncertainty from the fit is shown as the hatched band. Example spin-0 signal distributions for mX= 1.0 and 3.0 TeV are shown as solid lines, with σB(X→HH) set to 0.2 and 0.1 pb for the SL and DL channels, respectively. The bottom panes of each plot show the ratio of the data to the fit result. |
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Figure 6:
Expected upper limits at 95% confidence level (CL) for each of the 12 search categories individually. |
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Figure 7:
Observed and expected 95% CL upper limits on the product of the cross section and branching fraction to HH for a generic spin-0 (left) and spin-2 (right) boson X, as a function of mass. Example radion and bulk graviton predictions are also shown. The HH branching fraction is assumed to be 25 and 10%, respectively. |
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Figure 7-a:
Observed and expected 95% CL upper limits on the product of the cross section and branching fraction to HH for a generic spin-0 (left) and spin-2 (right) boson X, as a function of mass. Example radion and bulk graviton predictions are also shown. The HH branching fraction is assumed to be 25 and 10%, respectively. |
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Figure 7-b:
Observed and expected 95% CL upper limits on the product of the cross section and branching fraction to HH for a generic spin-0 (left) and spin-2 (right) boson X, as a function of mass. Example radion and bulk graviton predictions are also shown. The HH branching fraction is assumed to be 25 and 10%, respectively. |
Tables | |
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Table 1:
SL channel event categorization and corresponding category labels. All combinations of the two lepton flavor, two bˉb jet tagging, and two H→WW∗ decay purity selections are used to form eight independent event categories. The lower τ2/τ1 working point is 0.55 in 2016 and 0.45 in 2017 and 2018. |
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Table 2:
DL channel event categorization and corresponding category labels. All combinations of the two lepton flavor and two bˉb jet tagging selections are used to form four independent event categories. |
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Table 3:
SL channel: the efficiency of each selection criterion with the rest of the full selection applied. The efficiencies for the total expected SM background and signal at 1.0 TeV and 3.0 TeV are shown. |
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Table 4:
DL channel: the efficiency of each selection criterion with the rest of the full selection applied. The efficiencies for the total expected SM background and signal at 1.0 TeV and 3.0 TeV are shown. |
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Table 5:
The four background components with their kinematical properties and defining number of generator-level quarks within ΔR< 0.8 of the bˉb jet axis. |
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Table 6:
Background systematic uncertainties included in the maximum likelihood fit. The Np column indicates the number of nuisance parameters used to model the uncertainty. In the last two columns, σI refers to the initial estimate of the uncertainty, and σC refers to the constrained uncertainty obtained post-fit. For the q/g,tˉt, and lostt/W shape uncertainties, "scale'' uncertainties are those implemented with alternative templates with multiplicative parameters proportional to mass m, and "inverse scale'' are for proportional to 1/m. |
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Table 7:
Signal systematic uncertainties included in the maximum likelihood fit. The Np column indicates the number of nuisance parameters used to model the uncertainty. In the "Uncertainty values'' column, some uncertainties are noted to affect both the yield (Y) and mHH shape (S for scale, R for resolution) of the signal. All other uncertainties, except the SD jet mass uncertainties, are uncertainties on the signal yield. |
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Table 8:
Event yields broken down by search category. For each category, shown are the event yields observed in data, expected after a fit to the B-only model, and the corresponding relative uncertainty. |
Summary |
A search has been presented for new bosons decaying to a pair of Higgs bosons (H) where one decays into a bottom quark pair (bˉb) and the other decays via one of three different modes into final states with leptons. The large Lorentz boost of the Higgs bosons produces a distinct experimental signature with one large-radius jet with substructure consistent with the decay H→bˉb. For the Higgs boson that does not decay to bˉb, considered are the single-lepton decay H→WW∗→ℓgnqˉq and the dilepton decays H→WW∗→ℓνℓν and H→ττ→ℓννℓνν. In the single-lepton channel, the experimental signature also contains a second large-radius jet with a nearby lepton, which is consistent with the decay of H→WW∗. In the dilepton channel, the experimental signature contains two leptons and significant missing transverse momentum. This search uses a sample of proton-proton collisions at √s= 13 TeV collected by the CMS detector at the LHC. The primary Standard Model backgrounds -- production of top quark pairs and Z/γ∗+jets in the dilepton channel only -- are suppressed by reconstructing the HH decay chain and applying selections to discriminate signal from background. The signal and background yields are estimated by a two-dimensional template fit in the plane of the bˉb jet mass and the HH resonance mass. The templates are validated in a variety of data control regions and are shown to model the data well. The data are consistent with the expected Standard Model background. Upper limits are set on the product of the cross section and branching fraction for new bosons decaying to HH. The observed limit at 95% confidence level for a spin-0 boson ranges from 24.5 fb at 0.8 TeV to 0.78 fb at 4.5 TeV, while the limit for a spin-2 boson is 16.7 fb at 0.8 TeV and 0.67 fb at 4.5 TeV. This search produces the most stringent exclusion limits to date for X→HH production modes with leptons in the final state. The current sensitivity to X→HH production is stronger than or comparable to those from searches in other channels for HH resonances with masses above 800 GeV. |
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Compact Muon Solenoid LHC, CERN |
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