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Leading order Feynman diagrams for SM nonresonant \HH production via gluon fusion, including the ``triangle'' diagram (left) and the ``box'' diagram (right).

Leading order Feynman diagrams for SM nonresonant \HH production via gluon fusion, including the ``triangle'' diagram (left) and the ``box'' diagram (right).

Leading order Feynman diagrams for nonresonant \HH production via gluon fusion in an EFT approach, where loop-mediated contact interactions between (\cmsLeft) two gluons and one \PH boson, (\cmsMid) two gluons and two \PH bosons, and (\cmsRight) two top quarks and two \PH bosons are parametrized by three effective couplings: \cg, \cgg, and \ctwo.

Leading order Feynman diagrams for nonresonant \HH production via gluon fusion in an EFT approach, where loop-mediated contact interactions between (\cmsLeft) two gluons and one \PH boson, (\cmsMid) two gluons and two \PH bosons, and (\cmsRight) two top quarks and two \PH bosons are parametrized by three effective couplings: \cg, \cgg, and \ctwo.

Leading order Feynman diagrams for nonresonant \HH production via gluon fusion in an EFT approach, where loop-mediated contact interactions between (\cmsLeft) two gluons and one \PH boson, (\cmsMid) two gluons and two \PH bosons, and (\cmsRight) two top quarks and two \PH bosons are parametrized by three effective couplings: \cg, \cgg, and \ctwo.

Leading order Feynman diagram for resonant \HH production.

Distributions in a few observables used as inputs to the BDT classifiers in the \llss and \lllnot categories: the scalar \pt sum, denoted as \HT, of the two reconstructed \lep and all small-radius jets in the \llss category (\cmsTop \cmsLeft); the angular separation $\Delta R$ between the two \lep in the \llss category (\cmsTop \cmsRight); the angular separation between $\lep_{3}$ and the nearest small-radius jet in the \lllnot category (\cmsBottom \cmsLeft); and \metLD in the \lllnot category (\cmsBottom \cmsRight). The $\lep_{3}$ in the \lllnot category is defined as the \lep that is not part of the opposite-sign \leplep pair of lowest mass. The normalization and shape of the distributions expected for the different background processes are shown for the values of nuisance parameters obtained from an ML fit in which the \HH signal is constrained to be zero. The gray shaded area indicates the sum of statistical and systematic uncertainties on the background prediction obtained from this ML fit.

Distributions in a few observables used as inputs to the BDT classifiers in the \llss and \lllnot categories: the scalar \pt sum, denoted as \HT, of the two reconstructed \lep and all small-radius jets in the \llss category (\cmsTop \cmsLeft); the angular separation $\Delta R$ between the two \lep in the \llss category (\cmsTop \cmsRight); the angular separation between $\lep_{3}$ and the nearest small-radius jet in the \lllnot category (\cmsBottom \cmsLeft); and \metLD in the \lllnot category (\cmsBottom \cmsRight). The $\lep_{3}$ in the \lllnot category is defined as the \lep that is not part of the opposite-sign \leplep pair of lowest mass. The normalization and shape of the distributions expected for the different background processes are shown for the values of nuisance parameters obtained from an ML fit in which the \HH signal is constrained to be zero. The gray shaded area indicates the sum of statistical and systematic uncertainties on the background prediction obtained from this ML fit.

Distributions in a few observables used as inputs to the BDT classifiers in the \llss and \lllnot categories: the scalar \pt sum, denoted as \HT, of the two reconstructed \lep and all small-radius jets in the \llss category (\cmsTop \cmsLeft); the angular separation $\Delta R$ between the two \lep in the \llss category (\cmsTop \cmsRight); the angular separation between $\lep_{3}$ and the nearest small-radius jet in the \lllnot category (\cmsBottom \cmsLeft); and \metLD in the \lllnot category (\cmsBottom \cmsRight). The $\lep_{3}$ in the \lllnot category is defined as the \lep that is not part of the opposite-sign \leplep pair of lowest mass. The normalization and shape of the distributions expected for the different background processes are shown for the values of nuisance parameters obtained from an ML fit in which the \HH signal is constrained to be zero. The gray shaded area indicates the sum of statistical and systematic uncertainties on the background prediction obtained from this ML fit.

Distributions in a few observables used as inputs to the BDT classifiers in the \llss and \lllnot categories: the scalar \pt sum, denoted as \HT, of the two reconstructed \lep and all small-radius jets in the \llss category (\cmsTop \cmsLeft); the angular separation $\Delta R$ between the two \lep in the \llss category (\cmsTop \cmsRight); the angular separation between $\lep_{3}$ and the nearest small-radius jet in the \lllnot category (\cmsBottom \cmsLeft); and \metLD in the \lllnot category (\cmsBottom \cmsRight). The $\lep_{3}$ in the \lllnot category is defined as the \lep that is not part of the opposite-sign \leplep pair of lowest mass. The normalization and shape of the distributions expected for the different background processes are shown for the values of nuisance parameters obtained from an ML fit in which the \HH signal is constrained to be zero. The gray shaded area indicates the sum of statistical and systematic uncertainties on the background prediction obtained from this ML fit.

Distributions in \mT in the \threeLeptonCR CR (\cmsLeft) and in $m_{4\lep}$ in the \fourLeptonCR CR (\cmsRight). The normalization and shape of the distributions expected for $\PW\PZ$, $\PZ\PZ$, and other background processes are shown for the values of nuisance parameters obtained from the ML fit described in Section~\ref{sec:results}. The gray shaded area indicates the sum of statistical and systematic uncertainties on the background prediction obtained from the ML fit.

Distributions in \mT in the \threeLeptonCR CR (\cmsLeft) and in $m_{4\lep}$ in the \fourLeptonCR CR (\cmsRight). The normalization and shape of the distributions expected for $\PW\PZ$, $\PZ\PZ$, and other background processes are shown for the values of nuisance parameters obtained from the ML fit described in Section~\ref{sec:results}. The gray shaded area indicates the sum of statistical and systematic uncertainties on the background prediction obtained from the ML fit.

Distributions in \mT in the \llss CR (\cmsLeft) and in the mass of the \HH candidate in the \lltt CR (\cmsRight). The normalization and shape of the distributions expected for the misidentified \lep/\tauh background and other background processes are shown for the values of nuisance parameters obtained from an ML fit in which the \HH signal is constrained to be zero. The gray shaded area indicates the sum of statistical and systematic uncertainties on the background prediction obtained from this ML fit.

Distributions in \mT in the \llss CR (\cmsLeft) and in the mass of the \HH candidate in the \lltt CR (\cmsRight). The normalization and shape of the distributions expected for the misidentified \lep/\tauh background and other background processes are shown for the values of nuisance parameters obtained from an ML fit in which the \HH signal is constrained to be zero. The gray shaded area indicates the sum of statistical and systematic uncertainties on the background prediction obtained from this ML fit.

Distribution in the output of the BDT trained for nonresonant \HH production and evaluated for the benchmark scenario JHEP04 BM7 for the \llss (\cmsTop \cmsLeft), \lllnot (\cmsTop \cmsRight), and \llll (\cmsBottom) categories. The SM \HH signal is shown for a cross section amounting to 30 times the value predicted in the SM. The normalization and shape of the distributions expected for the background processes are shown for the values of nuisance parameters obtained from the ML fit of the signal+background hypothesis to the data. The gray shaded area indicates the sum of statistical and systematic uncertainties on the background prediction obtained from the ML fit. No data events are observed in the three rightmost bins of the BDT output distribution in the \llll category.

Distribution in the output of the BDT trained for nonresonant \HH production and evaluated for the benchmark scenario JHEP04 BM7 for the \llss (\cmsTop \cmsLeft), \lllnot (\cmsTop \cmsRight), and \llll (\cmsBottom) categories. The SM \HH signal is shown for a cross section amounting to 30 times the value predicted in the SM. The normalization and shape of the distributions expected for the background processes are shown for the values of nuisance parameters obtained from the ML fit of the signal+background hypothesis to the data. The gray shaded area indicates the sum of statistical and systematic uncertainties on the background prediction obtained from the ML fit. No data events are observed in the three rightmost bins of the BDT output distribution in the \llll category.

Distribution in the output of the BDT trained for nonresonant \HH production and evaluated for the benchmark scenario JHEP04 BM7 for the \llss (\cmsTop \cmsLeft), \lllnot (\cmsTop \cmsRight), and \llll (\cmsBottom) categories. The SM \HH signal is shown for a cross section amounting to 30 times the value predicted in the SM. The normalization and shape of the distributions expected for the background processes are shown for the values of nuisance parameters obtained from the ML fit of the signal+background hypothesis to the data. The gray shaded area indicates the sum of statistical and systematic uncertainties on the background prediction obtained from the ML fit. No data events are observed in the three rightmost bins of the BDT output distribution in the \llll category.

Distribution in the output of the BDT trained for nonresonant \HH production and evaluated for the benchmark scenario JHEP04 BM7 for the \lllt (\cmsTop \cmsLeft), \lltt (\cmsTop \cmsRight), \lttt (\cmsBottom \cmsLeft), and \noltttt (\cmsBottom \cmsRight) categories. The SM \HH signal is shown for a cross section amounting to 30 times the value predicted in the SM. The normalization and shape of the distributions expected for the background processes are shown for the values of nuisance parameters obtained from the ML fit of the signal+background hypothesis to the data. The gray shaded area indicates the sum of statistical and systematic uncertainties on the background prediction obtained from the ML fit.

Distribution in the output of the BDT trained for nonresonant \HH production and evaluated for the benchmark scenario JHEP04 BM7 for the \lllt (\cmsTop \cmsLeft), \lltt (\cmsTop \cmsRight), \lttt (\cmsBottom \cmsLeft), and \noltttt (\cmsBottom \cmsRight) categories. The SM \HH signal is shown for a cross section amounting to 30 times the value predicted in the SM. The normalization and shape of the distributions expected for the background processes are shown for the values of nuisance parameters obtained from the ML fit of the signal+background hypothesis to the data. The gray shaded area indicates the sum of statistical and systematic uncertainties on the background prediction obtained from the ML fit.

Distribution in the output of the BDT trained for nonresonant \HH production and evaluated for the benchmark scenario JHEP04 BM7 for the \lllt (\cmsTop \cmsLeft), \lltt (\cmsTop \cmsRight), \lttt (\cmsBottom \cmsLeft), and \noltttt (\cmsBottom \cmsRight) categories. The SM \HH signal is shown for a cross section amounting to 30 times the value predicted in the SM. The normalization and shape of the distributions expected for the background processes are shown for the values of nuisance parameters obtained from the ML fit of the signal+background hypothesis to the data. The gray shaded area indicates the sum of statistical and systematic uncertainties on the background prediction obtained from the ML fit.

Distribution in the output of the BDT trained for nonresonant \HH production and evaluated for the benchmark scenario JHEP04 BM7 for the \lllt (\cmsTop \cmsLeft), \lltt (\cmsTop \cmsRight), \lttt (\cmsBottom \cmsLeft), and \noltttt (\cmsBottom \cmsRight) categories. The SM \HH signal is shown for a cross section amounting to 30 times the value predicted in the SM. The normalization and shape of the distributions expected for the background processes are shown for the values of nuisance parameters obtained from the ML fit of the signal+background hypothesis to the data. The gray shaded area indicates the sum of statistical and systematic uncertainties on the background prediction obtained from the ML fit.

Observed and expected 95\% \CL upper limits on the SM \HH production cross section, obtained for both individual search categories and from a simultaneous fit of all seven categories combined.

Observed and expected 95\% \CL upper limits on the \HH production cross section as a function of the \PH boson self-coupling strength modifier \kappal. All \PH boson couplings other than $\lambda$ are assumed to have the values predicted in the SM. The left plot shows the result obtained by combining all seven search categories, while the right plot shows the limits obtained for each category separately. The red curve in the left plot represents the SM prediction for the \HH production cross section as a function of \kappal, and the red shaded band the theoretical uncertainty in this prediction.

Observed and expected 95\% \CL upper limits on the \HH production cross section as a function of the \PH boson self-coupling strength modifier \kappal. All \PH boson couplings other than $\lambda$ are assumed to have the values predicted in the SM. The left plot shows the result obtained by combining all seven search categories, while the right plot shows the limits obtained for each category separately. The red curve in the left plot represents the SM prediction for the \HH production cross section as a function of \kappal, and the red shaded band the theoretical uncertainty in this prediction.

Observed and expected 95\% \CL upper limits on the \HH production cross section for the twelve benchmark scenarios from Ref.~\cite{Carvalho:2015ttv}, the additional benchmark scenario 8a from Ref.~\cite{Buchalla:2018yce}, the seven benchmark scenarios from Ref.~\cite{Capozi:2019xsi}, and for the SM. The upper plot shows the result obtained by combining all seven search categories, while the lower plot shows the limits obtained for each category separately, and the combined limit.

Observed and expected 95\% \CL upper limits on the \HH production cross section for the twelve benchmark scenarios from Ref.~\cite{Carvalho:2015ttv}, the additional benchmark scenario 8a from Ref.~\cite{Buchalla:2018yce}, the seven benchmark scenarios from Ref.~\cite{Capozi:2019xsi}, and for the SM. The upper plot shows the result obtained by combining all seven search categories, while the lower plot shows the limits obtained for each category separately, and the combined limit.

Observed and expected limits on the \HH production cross section as a function of the effective coupling \ctwo (\cmsLeft), and the region excluded in the \kappat--\,\ctwo plane (\cmsRight). All limits are computed at 95\% \CL. \PH boson couplings other than the ones shown in the plots (\ctwo in the left plot and \ctwo and \kappat in the right plot) are assumed to have the values predicted by the SM.

Observed and expected limits on the \HH production cross section as a function of the effective coupling \ctwo (\cmsLeft), and the region excluded in the \kappat--\,\ctwo plane (\cmsRight). All limits are computed at 95\% \CL. \PH boson couplings other than the ones shown in the plots (\ctwo in the left plot and \ctwo and \kappat in the right plot) are assumed to have the values predicted by the SM.

Observed and expected regions excluded in the \kappat--\,\kappal (\cmsLeft) and \kappal--\,\ctwo (\cmsRight) planes. \PH boson couplings other than the ones shown in the plots (\kappal and \kappat in the left plot, and \ctwo and \kappal in the right plot) are assumed to have the values predicted by the SM.

Observed and expected regions excluded in the \kappat--\,\kappal (\cmsLeft) and \kappal--\,\ctwo (\cmsRight) planes. \PH boson couplings other than the ones shown in the plots (\kappal and \kappat in the left plot, and \ctwo and \kappal in the right plot) are assumed to have the values predicted by the SM.

Observed and expected 95\% \CL upper limits on the production of new particles \X of spin 0 (upper) and spin 2 (lower) and mass $m_{\X}$ in the range 250--1000\GeV, which decay to \PH boson pairs. The plot on the left shows the result obtained by combining all seven search categories, while the plot on the right shows the limits obtained for each category separately, and the combined limit.

Observed and expected 95\% \CL upper limits on the production of new particles \X of spin 0 (upper) and spin 2 (lower) and mass $m_{\X}$ in the range 250--1000\GeV, which decay to \PH boson pairs. The plot on the left shows the result obtained by combining all seven search categories, while the plot on the right shows the limits obtained for each category separately, and the combined limit.

Observed and expected 95\% \CL upper limits on the production of new particles \X of spin 0 (upper) and spin 2 (lower) and mass $m_{\X}$ in the range 250--1000\GeV, which decay to \PH boson pairs. The plot on the left shows the result obtained by combining all seven search categories, while the plot on the right shows the limits obtained for each category separately, and the combined limit.

Observed and expected 95\% \CL upper limits on the production of new particles \X of spin 0 (upper) and spin 2 (lower) and mass $m_{\X}$ in the range 250--1000\GeV, which decay to \PH boson pairs. The plot on the left shows the result obtained by combining all seven search categories, while the plot on the right shows the limits obtained for each category separately, and the combined limit.

Observed and expected 95\% \CL upper limits on the production of new particles \X of spin 0 (upper) and spin 2 (lower) and mass $m_{\X}$ in the range 250--1000\GeV, which decay to \PH boson pairs. The plot on the left shows the result obtained by combining all seven search categories, while the plot on the right shows the limits obtained for each category separately, and the combined limit.

Observed and expected 95\% \CL upper limits on the production of new particles \X of spin 0 (upper) and spin 2 (lower) and mass $m_{\X}$ in the range 250--1000\GeV, which decay to \PH boson pairs. The plot on the left shows the result obtained by combining all seven search categories, while the plot on the right shows the limits obtained for each category separately, and the combined limit.

Distribution in BDT classifier output for resonances of spin 2 and mass 750\GeV in the \twoLeptonssZeroTau (\cmsLeft) and \threeLeptonZeroTau (\cmsRight) categories. The resonant \HH signal is shown for a cross section amounting to 1\pb. The distributions expected for the background processes are shown for the values of nuisance parameters obtained from the ML fit of the signal+background hypothesis to the data.

Distribution in BDT classifier output for resonances of spin 2 and mass 750\GeV in the \twoLeptonssZeroTau (\cmsLeft) and \threeLeptonZeroTau (\cmsRight) categories. The resonant \HH signal is shown for a cross section amounting to 1\pb. The distributions expected for the background processes are shown for the values of nuisance parameters obtained from the ML fit of the signal+background hypothesis to the data.