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CMS-HIG-14-034 ; CERN-PH-EP-2015-211
Searches for a heavy scalar boson H decaying to a pair of 125 GeV Higgs bosons hh or for a heavy pseudoscalar boson A decaying to Zh, in the final states with hττ
Phys. Lett. B 755 (2016) 217
Abstract: A search for a heavy scalar boson H decaying into a pair of lighter standard-model-like 125 GeV Higgs bosons h and a search for a heavy pseudoscalar boson A decaying into a Z and an h boson are presented. The searches are performed on a dataset corresponding to an integrated luminosity of 19.7 fb1 of pp collision data at a centre-of-mass energy of 8 TeV, collected by CMS in 2012. A final state consisting of two τ leptons and two b jets is used to search for the Hhh decay. A final state consisting of two τ leptons from the h boson decay, and two additional leptons from the Z boson decay, is used to search for the decay AZh. The results are interpreted in the context of both the minimal supersymmetric extension of the standard model and two-Higgs-doublet models. No excess is found above the standard model expectation and upper limits are set on the heavy boson production cross sections in the mass ranges 260 <mH< 350 GeV and 220 <mA< 350 GeV.
Figures Summary Additional Figures CMS Publications
Figures

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Figure 1:
Distribution of mT for events in the μτh final state, containing at least two additional jets. The W+jets background is included in the ``electroweak" category. Multijet events are indicated as QCD. The hhhbbττ selection requires mT< 30 GeV for the μτh and eτh final states.

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Figure 2:
Distribution of the variable LhT for events in the τhτh final state. The reducible background is estimated from data, instead the ZZ irreducible background from simulation.

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Figure 3-a:
Distributions of the reconstructed four-body mass with the kinematic fit after applying mass selections on mττ and mbb in the μτh channel. The plots are shown for events in the 2jet--0tag (a), 2jet--1tag (b), and 2jet--2tag (c) categories. The expected signal scaled by a factor 10 is shown superimposed as an open dashed histogram for tanβ= 2 and mh= 300 GeV in the low tanβ scenario of the MSSM. Expected background contributions are shown for the values of nuisance parameters (systematic uncertainties) obtained after fitting the signal plus background hypothesis to the data.

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Figure 3-b:
Distributions of the reconstructed four-body mass with the kinematic fit after applying mass selections on mττ and mbb in the μτh channel. The plots are shown for events in the 2jet--0tag (a), 2jet--1tag (b), and 2jet--2tag (c) categories. The expected signal scaled by a factor 10 is shown superimposed as an open dashed histogram for tanβ= 2 and mh= 300 GeV in the low tanβ scenario of the MSSM. Expected background contributions are shown for the values of nuisance parameters (systematic uncertainties) obtained after fitting the signal plus background hypothesis to the data.

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Figure 3-c:
Distributions of the reconstructed four-body mass with the kinematic fit after applying mass selections on mττ and mbb in the μτh channel. The plots are shown for events in the 2jet--0tag (a), 2jet--1tag (b), and 2jet--2tag (c) categories. The expected signal scaled by a factor 10 is shown superimposed as an open dashed histogram for tanβ= 2 and mh= 300 GeV in the low tanβ scenario of the MSSM. Expected background contributions are shown for the values of nuisance parameters (systematic uncertainties) obtained after fitting the signal plus background hypothesis to the data.

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Figure 4-a:
Distributions of the reconstructed four-body mass with the kinematic fit after applying mass selections on mττ and mbb in the eτh channel. The plots are shown for events in the 2jet--0tag (a), 2jet--1tag (b), and 2jet--2tag (c) categories. The expected signal scaled by a factor 10 is shown superimposed as an open dashed histogram for tanβ= 2 and mh= 300 GeV in the low tanβ scenario of the MSSM. Expected background contributions are shown for the values of nuisance parameters (systematic uncertainties) obtained after fitting the signal plus background hypothesis to the data.

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Figure 4-b:
Distributions of the reconstructed four-body mass with the kinematic fit after applying mass selections on mττ and mbb in the eτh channel. The plots are shown for events in the 2jet--0tag (a), 2jet--1tag (b), and 2jet--2tag (c) categories. The expected signal scaled by a factor 10 is shown superimposed as an open dashed histogram for tanβ= 2 and mh= 300 GeV in the low tanβ scenario of the MSSM. Expected background contributions are shown for the values of nuisance parameters (systematic uncertainties) obtained after fitting the signal plus background hypothesis to the data.

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Figure 4-c:
Distributions of the reconstructed four-body mass with the kinematic fit after applying mass selections on mττ and mbb in the eτh channel. The plots are shown for events in the 2jet--0tag (a), 2jet--1tag (b), and 2jet--2tag (c) categories. The expected signal scaled by a factor 10 is shown superimposed as an open dashed histogram for tanβ= 2 and mh= 300 GeV in the low tanβ scenario of the MSSM. Expected background contributions are shown for the values of nuisance parameters (systematic uncertainties) obtained after fitting the signal plus background hypothesis to the data.

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Figure 5-a:
Distributions of the reconstructed four-body mass with the kinematic fit after applying mass selections on mττ and mbb in the τhτh channel. The plots are shown for events in the 2jet--0tag (a), 2jet--1tag (b), and 2jet--2tag (c) categories. The expected signal scaled by a factor 10 is shown superimposed as an open dashed histogram for tanβ= 2 and mh= 300 GeV in the low tanβ scenario of the MSSM. Expected background contributions are shown for the values of nuisance parameters (systematic uncertainties) obtained after fitting the signal plus background hypothesis to the data.

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Figure 5-b:
Distributions of the reconstructed four-body mass with the kinematic fit after applying mass selections on mττ and mbb in the τhτh channel. The plots are shown for events in the 2jet--0tag (a), 2jet--1tag (b), and 2jet--2tag (c) categories. The expected signal scaled by a factor 10 is shown superimposed as an open dashed histogram for tanβ= 2 and mh= 300 GeV in the low tanβ scenario of the MSSM. Expected background contributions are shown for the values of nuisance parameters (systematic uncertainties) obtained after fitting the signal plus background hypothesis to the data.

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Figure 5-c:
Distributions of the reconstructed four-body mass with the kinematic fit after applying mass selections on mττ and mbb in the τhτh channel. The plots are shown for events in the 2jet--0tag (a), 2jet--1tag (b), and 2jet--2tag (c) categories. The expected signal scaled by a factor 10 is shown superimposed as an open dashed histogram for tanβ= 2 and mh= 300 GeV in the low tanβ scenario of the MSSM. Expected background contributions are shown for the values of nuisance parameters (systematic uncertainties) obtained after fitting the signal plus background hypothesis to the data.

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Figure 6-a:
Invariant mass distributions for different final states of the AZh process where Z decays to ee. The expected signal scaled by a factor 5 is shown superimposed as an open dashed histogram for tanβ= 2 and mA= 300 GeV in the low tanβ scenario of MSSM. Expected background contributions are shown for the values of nuisance parameters (systematic uncertainties) obtained after fitting the signal plus background hypothesis to the data.

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Figure 6-b:
Invariant mass distributions for different final states of the AZh process where Z decays to ee. The expected signal scaled by a factor 5 is shown superimposed as an open dashed histogram for tanβ= 2 and mA= 300 GeV in the low tanβ scenario of MSSM. Expected background contributions are shown for the values of nuisance parameters (systematic uncertainties) obtained after fitting the signal plus background hypothesis to the data.

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Figure 6-c:
Invariant mass distributions for different final states of the AZh process where Z decays to ee. The expected signal scaled by a factor 5 is shown superimposed as an open dashed histogram for tanβ= 2 and mA= 300 GeV in the low tanβ scenario of MSSM. Expected background contributions are shown for the values of nuisance parameters (systematic uncertainties) obtained after fitting the signal plus background hypothesis to the data.

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Figure 6-d:
Invariant mass distributions for different final states of the AZh process where Z decays to ee. The expected signal scaled by a factor 5 is shown superimposed as an open dashed histogram for tanβ= 2 and mA= 300 GeV in the low tanβ scenario of MSSM. Expected background contributions are shown for the values of nuisance parameters (systematic uncertainties) obtained after fitting the signal plus background hypothesis to the data.

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Figure 7-a:
Invariant mass distributions for different final states of the AZh process where Z decays to μμ. The expected signal scaled by a factor 5 is shown superimposed as an open dashed histogram for tanβ= 2 and mA= 300 GeV in the low tanβ scenario of MSSM. Expected background contributions are shown for the values of nuisance parameters (systematic uncertainties) obtained after fitting the signal plus background hypothesis to the data.

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Figure 7-b:
Invariant mass distributions for different final states of the AZh process where Z decays to μμ. The expected signal scaled by a factor 5 is shown superimposed as an open dashed histogram for tanβ= 2 and mA= 300 GeV in the low tanβ scenario of MSSM. Expected background contributions are shown for the values of nuisance parameters (systematic uncertainties) obtained after fitting the signal plus background hypothesis to the data.

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Figure 7-c:
Invariant mass distributions for different final states of the AZh process where Z decays to μμ. The expected signal scaled by a factor 5 is shown superimposed as an open dashed histogram for tanβ= 2 and mA= 300 GeV in the low tanβ scenario of MSSM. Expected background contributions are shown for the values of nuisance parameters (systematic uncertainties) obtained after fitting the signal plus background hypothesis to the data.

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Figure 7-d:
Invariant mass distributions for different final states of the AZh process where Z decays to μμ. The expected signal scaled by a factor 5 is shown superimposed as an open dashed histogram for tanβ= 2 and mA= 300 GeV in the low tanβ scenario of MSSM. Expected background contributions are shown for the values of nuisance parameters (systematic uncertainties) obtained after fitting the signal plus background hypothesis to the data.

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Figure 8-a:
Upper limits at 95% CL on the hhhbbττ cross section times branching fraction for the μτh (a), eτh (b), τhτh (c), and for final states combined (d)

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Figure 8-b:
Upper limits at 95% CL on the hhhbbττ cross section times branching fraction for the μτh (a), eτh (b), τhτh (c), and for final states combined (d)

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Figure 8-c:
Upper limits at 95% CL on the hhhbbττ cross section times branching fraction for the μτh (a), eτh (b), τhτh (c), and for final states combined (d)

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Figure 8-d:
Upper limits at 95% CL on the hhhbbττ cross section times branching fraction for the μτh (a), eτh (b), τhτh (c), and for final states combined (d)

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Figure 9-a:
Upper limits at 95% CL on cross section times branching fraction on AZhLLττ for eμ (a), μτh (b), eτh (c), and τhτh (d) final states.

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Figure 9-b:
Upper limits at 95% CL on cross section times branching fraction on AZhLLττ for eμ (a), μτh (b), eτh (c), and τhτh (d) final states.

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Figure 9-c:
Upper limits at 95% CL on cross section times branching fraction on AZhLLττ for eμ (a), μτh (b), eτh (c), and τhτh (d) final states.

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Figure 9-d:
Upper limits at 95% CL on cross section times branching fraction on AZhLLττ for eμ (a), μτh (b), eτh (c), and τhτh (d) final states.

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Figure 10-a:
Upper limits at 95% CL on cross section times branching fraction on AZhLLττ for all ττ final states combined (a) and comparison of the different final states (b).

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Figure 10-b:
Upper limits at 95% CL on cross section times branching fraction on AZhLLττ for all ττ final states combined (a) and comparison of the different final states (b).

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Figure 11:
The 95% CL exclusion region in the mA-tanβ plane for the low-tanβ scenario as discussed in the introduction, combining the results of the hhhbbττ and the AZhττ analysis. The area highlighted in blue below the black curve marks the observed exclusion. The dashed curve and the grey bands show the expected exclusion limit with the relative uncertainty. The red area with the back-slash lines at the lower-left corner of the plot indicates the region excluded by the mass of the SM-like scalar boson being 125 GeV. The limit falls off rapidly as mA approaches 350 GeV because decays of the A to two top quarks are becoming kinematically allowed.

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Figure 12:
The 95% CL exclusion regions in the cos(βα) vs. tanβ plane of 2HDM Type II model for mA=mh=300 GeV, combining the results of the hhhbbττ and AZhττ analysis. The areas highlighted in blue bounded by the black curves mark the observed exclusion. The dashed curves and the grey bands show the expected exclusion limit with the relative uncertainty.
Summary
A search for a heavy scalar Higgs boson (H) decaying into a pair of SM-like Higgs bosons (hh) and a search for a heavy neutral pseudoscalar Higgs boson (A) decaying into a Z boson and a SM-like Higgs boson (h), have been performed using events recorded by the CMS experiment at the LHC. The dataset corresponds to an integrated luminosity of 19.7 fb1, recorded at 8 TeV centre-of-mass energy in 2012. No evidence for a signal has been found and exclusion limits on the production cross section times branching fraction for the processes Hhhbbττ and AZhLLττ are presented. The results are also interpreted in the context of the MSSM and 2HDM models.
Additional Figures

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Additional Figure 1:
Observed and predicted mA distributions in the +eμ channel, for the A Zh ττ analysis. The normalization of the predicted background distributions corresponds to the result of the global fit. The signal distribution is normalized to the MSSM low-tanβ scenario with tan β=2.

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Additional Figure 2:
Observed and predicted mA distributions in the +eτh channel, for the A Zh ττ analysis. The normalization of the predicted background distributions corresponds to the result of the global fit. The signal distribution is normalized to the MSSM low-tanβ scenario with tan β=2.

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Additional Figure 3:
Observed and predicted mA distributions in the +μτh channel, for the A Zhττ analysis. The normalization of the predicted background distributions corresponds to the result of the global fit. The signal distribution is normalized to the MSSM low-tanβ scenario with tan β=2.

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Additional Figure 4:
Observed and predicted mA distributions in the +τhτh channel, for the A Zhττ analysis. The normalization of the predicted background distributions corresponds to the result of the global fit. The signal distribution is normalized to the MSSM low-tanβ scenario with tan β=2.

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Additional Figure 5:
Observed and predicted mA distributions in all eight final states combined, for the A Zhττ analysis. The normalization ofthe predicted background distributions corresponds to the result of the global fit. The signal distribution is normalized to the MSSM low-tanβ scenario with tan β=2.

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Additional Figure 6:
Values of cross-section times branching ratio for the AZhLLττ process in the low-tanβ scenario. The points indicate the values available from the theoretical calculations.

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Additional Figure 7:
The 95% CL exclusion region in the mA - tanβ plane for the low-tanβ scenario as discussed in the introduction, using the results of the A Zh ττ analysis. The red area indicates the region excluded by the mass of the SM-like scalar being inconsistent with 125 GeV.

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Additional Figure 8:
Values of cross-section times branching ratio for the AZhLLττ process in 2HDM Type II model. The points indicate the values available from the theoretical calculations. Areas in white have a value lower than that indicated in the legend, and are far from exclusion.

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Additional Figure 9:
The 95% CL exclusion regions in the cos(βα) - tanβ plane of 2HDM Type II model for mA = mH = 300 GeV, using the results of the A Zh ττ analysis.

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Additional Figure 10:
Rate with which jets are misidentified as electrons, in +eμ final states, in the barrel, as a function of the pT of the closest jet to the electron for A Zh ττ analysis.

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Additional Figure 11:
Rate with which jets are identified as electrons, in +eμ final states, in the endcap, as a function of the pT of the closest jet to the electron for A Zh ττ analysis.

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Additional Figure 12:
Rate with which jets are misidentified as muons, in +eμ final states, in the barrel, as a function of the pT of the closest jet to the muon for A Zh ττ analysis.

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Additional Figure 13:
Rate with which jets are misidentified as muons, in +eμ final states, in the endcap, as a function of the pT of the closest jet to the muon for A Zh ττ analysis.

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Additional Figure 14:
Rate with which jets are misidentified as electrons, in +eτh final states, in the endcap, as a function of the pT of the closest jet to the electron forA Zh ττ analysis.

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Additional Figure 15:
Rate with which jets are misidentified as muons, in +μτh final states, in the barrel and the endcap regions combined, as a function of the pT of the closest jet to the muon for A Zh ττ analysis.

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Additional Figure 16:
Rate with which jets are misidentified as hadronically decaying taus, in +τh final states, in the barrel, as a function of the pT of the closest jet to the tau for A Zh ττ analysis.

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Additional Figure 17:
Rate with which jets are misidentified as hadronically decaying taus, in +τh final states, in the endcap, as a function of the pT of the closest jet to the tau for A Zh ττ analysis.

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Additional Figure 18:
Rate with which jets are misidentified as hadronically decaying taus, in +τhτh final states, in the barrel, as a function of the pT of the closest jet to the tau for A Zh analysis.

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Additional Figure 19:
Rate with which jets are misidentified as hadronically decaying taus, in ll+τhτh final states, in the endcap, as a function of the pT of the closest jet to the tau for A Zh analysis.

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Additional Figure 20:
Comparison between 4-body mass distribution with and without the kinematic fit applied for signal events in the μτh channel and 2jet-1tag category of the Hhh bbττ analysis with mH = 300 GeV.

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Additional Figure 21:
Mass of the candidate di-tau pair mττ for events in the μτh final state and 2jet-1tag category of the Hhh bbττ analysis. Events in a window around mh=125 GeV of 90 < mττ < 150 GeV are used for signal extraction.

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Additional Figure 22:
Mass of the candidate di-jet pair mjj for events in the μτh final state and 2jet-1tag category of the Hhh bbττ analysis. Events in a window around mh=125 GeV of 70 < mjj < 150 GeV are used for signal extraction.

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Additional Figure 23:
Mass of the candidate di-tau pair mττ for events in the μτh final state and 2jet-2tag category of the Hhh bbττ analysis. Events in a window around mh=125 GeV of 90 < mττ < 150 GeV are used for signal extraction.

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Additional Figure 24:
Mass of the candidate di-jet pair mjj for events in the μτh final state and 2jet-2tag category of the Hhh bbττ analysis. Events in a window around mh=125 GeV of 70 < mjj < 150 GeV are used for signal extraction.

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Additional Figure 25:
Mass of the candidate di-tau pair mττ for events in the eτh final state and 2jet-1tag category of the Hhh bbττ analysis. Events in a window around mh=125 GeV of 90 < mττ < 150 GeV are used for signal extraction.

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Additional Figure 26:
Mass of the candidate di-jet pair mjj for events in the eτh final state and 2jet-1tag category of the Hhh bbττ analysis. Events in a window around mh=125 GeV of 70 < mjj < 150 GeV are used for signal extraction.

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Additional Figure 27:
Mass of the candidate di-tau pair mττ for events in the eτh final state and 2jet-2tag category of the Hhh bbττ analysis. Events in a window around mh=125 GeV of 90 < mττ < 150 GeV are used for signal extraction.

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Additional Figure 28:
Mass of the candidate di-jet pair mjj for events in the eτh final state and 2jet-2tag category of the Hhh bbττ analysis. Events in a window around mh=125 GeV of 70 < mjj < 150 GeV are used for signal extraction.

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Additional Figure 29:
Mass of the candidate di-tau pair mττ for events in the τhτh final state and 2jet-1tag category of the Hhh bbττ analysis. Events in a window around mh=125 GeV of 90 < mττ < 150 GeV are used for signal extraction.

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Additional Figure 30:
Mass of the candidate di-jet pair mjj for events in the τhτh final state and 2jet-1tag category of the Hhh bbττ analysis. Events in a window around mh=125 GeV of 70 < mjj < 150 GeV are used for signal extraction.

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Additional Figure 31:
Mass of the candidate di-tau pair mττ for events in the τhτh final state and 2jet-2tag category of the Hhhbbττ analysis. Events in a window around mh=125 GeV of 90 < mττ < 150 GeV are used for signal extraction.

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Additional Figure 32:
Mass of the candidate di-jet pair mjj for events in the τhτh final state and 2jet-2tag category of the Hhh bbττ analysis. Events in a window around mh=125 GeV of 70 < mjj < 150 GeV are used for signal extraction.

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Additional Figure 33:
Comparison of the expected limits for the Hhh bbττ analysis, separated by final state.

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Additional Figure 34:
Values of cross-section times branching ratio for the Hhh bbττ process in the in the mA -tanβ plane for the low-tanβ scenario. The points indicate the values available from the theoretical calculations. Areas in white have a value lower than that indicated in the legend, and are far from exclusion.

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Additional Figure 35:
Values of cross-section times branching ratio for the Hhhbbττ process in the type 2 2HDM scenario. The points indicate the values available from the theoretical calculations. Areas in white have a value lower than that indicated in the legend, and are far from exclusion.

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Additional Figure 36:
The 95% CL exclusion regions in the cos(βα) - tanβ plane of 2HDM Type II model for mA = mH = 300 GeV, using the results of the H hh bbττ analysis

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Additional Figure 37:
Comparison of limits on cross section times branching ratio for the Hhh process with analyses in other final states.
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