CMSPASHIG16024  
Search for Higgs boson pair production in the $\mathrm{b}\overline{\mathrm{b}} \ell\nu \ell\nu$ final state at $ \sqrt{s} = $ 13 TeV  
CMS Collaboration  
August 2016  
Abstract: A search for pairproduced Higgs bosons decaying respectively into $\mathrm{b}\overline{\mathrm{b}}$ and VV (with V either a W or a Z boson), with subsequent VV decays into two leptons and two neutrinos, is presented. The analysis is based on a sample of protonproton collisions at $ \sqrt{s} = $ 13 TeV at the LHC corresponding to an integrated luminosity of 2.30 fb$^{1}$. The search signature is a resonance in the invariant mass distribution of the bjet pair at the Higgs boson mass in combination with high scores of a boosted decision tree discriminant based on kinematic information. Data and predictions from the standard model (SM) are in agreement within uncertainties. For the SM hh hypothesis, the data are observed (expected) to exclude a production crosssection times branching ratio of 166.7 (92.8$^{+59.9}_{33.4}$) fb, corresponding to approximately 400 times the SM cross section. Lack of deviation from the SM predictions in the observations is used to place constraints on different scenarios considering anomalous couplings which could affect the rate and kinematics of hh production.  
Links: CDS record (PDF) ; inSPIRE record ; CADI line (restricted) ; 
Figures & Tables  Summary  Additional Figures & Material  References  CMS Publications 

Figures  
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Figure 1a:
Higgs pair production diagrams via gluon fusion for both SM (a,b,c) and BSM (d,e). 
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Figure 1b:
Higgs pair production diagrams via gluon fusion for both SM (a,b,c) and BSM (d,e). 
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Figure 1c:
Higgs pair production diagrams via gluon fusion for both SM (a,b,c) and BSM (d,e). 
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Figure 1d:
Higgs pair production diagrams via gluon fusion for both SM (a,b,c) and BSM (d,e). 
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Figure 1e:
Higgs pair production diagrams via gluon fusion for both SM (a,b,c) and BSM (d,e). 
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Figure 2a:
The $ {p_{\mathrm {T}}} ^{ {\ell} {\ell} }$ (a) and $ {p_{\mathrm {T}}} ^{ {\mathrm {j}} {\mathrm {j}} }$ (b) distributions for data and simulated events after requiring two leptons, two btagged jets, and $ {\mathrm {m}_{ {\ell} {\ell} }} < \rm {m}_{ {\mathrm {Z}} }  15$GeV, for all dilepton channels ($ {\mathrm {e}} {\mathrm {e}}$, $ {\mathrm {e}} {\mu } $, $ {\mu } {\mathrm {e}}$ and $ {\mu } {\mu } $). Four BMs along with the SM signal are shown as solid lines. The signal crosssections times branching fraction are arbitrarily normalized to 5pb for display purposes. Hashed area corresponds to postfit uncertainties, as described in section 6. 
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Figure 2b:
The $ {p_{\mathrm {T}}} ^{ {\ell} {\ell} }$ (a) and $ {p_{\mathrm {T}}} ^{ {\mathrm {j}} {\mathrm {j}} }$ (b) distributions for data and simulated events after requiring two leptons, two btagged jets, and $ {\mathrm {m}_{ {\ell} {\ell} }} < \rm {m}_{ {\mathrm {Z}} }  15$GeV, for all dilepton channels ($ {\mathrm {e}} {\mathrm {e}}$, $ {\mathrm {e}} {\mu } $, $ {\mu } {\mathrm {e}}$ and $ {\mu } {\mu } $). Four BMs along with the SM signal are shown as solid lines. The signal crosssections times branching fraction are arbitrarily normalized to 5pb for display purposes. Hashed area corresponds to postfit uncertainties, as described in section 6. 
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Figure 3a:
The BDT output (a) and ${\mathrm {m}_{ {\mathrm {j}} {\mathrm {j}} }}$ (b) distributions for data and simulated events for all dilepton channels ($ {\mathrm {e}} {\mathrm {e}}$, $ {\mathrm {e}} {\mu } $, $ {\mu } {\mathrm {e}}$ and $ {\mu } {\mu } $) after requiring all selection cuts. Four BMs along with the SM signal are shown as solid lines. The signal crosssections times branching fraction are arbitrarily normalized to 5 pb. Hashed area corresponds to postfit uncertainties, as described in section 6. 
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Figure 3b:
The BDT output (a) and ${\mathrm {m}_{ {\mathrm {j}} {\mathrm {j}} }}$ (b) distributions for data and simulated events for all dilepton channels ($ {\mathrm {e}} {\mathrm {e}}$, $ {\mathrm {e}} {\mu } $, $ {\mu } {\mathrm {e}}$ and $ {\mu } {\mu } $) after requiring all selection cuts. Four BMs along with the SM signal are shown as solid lines. The signal crosssections times branching fraction are arbitrarily normalized to 5 pb. Hashed area corresponds to postfit uncertainties, as described in section 6. 
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Figure 4:
BDT output distribution for data and simulated events for all dilepton channels ($ {\mathrm {e}} {\mathrm {e}}$, $ {\mathrm {e}} {\mu } $, $ {\mu } {\mathrm {e}}$ and $ {\mu } {\mu } $) in three different ${\mathrm {m}_{ {\mathrm {j}} {\mathrm {j}} }}$ regions: $ {\mathrm {m}_{ {\mathrm {j}} {\mathrm {j}} }} < $ 75 GeV (a), $ {\mathrm {m}_{ {\mathrm {j}} {\mathrm {j}} }} \in $ [75, 140[ GeV (b) and $ {\mathrm {m}_{ {\mathrm {j}} {\mathrm {j}} }} \geq $ 140 GeV (c). Four BMs along with the SM signal are shown as solid lines. The signal crosssections times branching fraction are arbitrarily normalized to 5pb. Hashed area corresponds to postfit uncertainties, as described in section 6. 
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Figure 5a:
Expected and observed 95% CL upper limits on the Higgs pair production cross section times branching fraction for $ {\mathrm {h}} {\mathrm {h}} \to { {\mathrm {b}} {\overline {\mathrm {b}}} } {\mathrm {V}} {\mathrm {V}} \to { {\mathrm {b}} {\overline {\mathrm {b}}} } {\ell} {\nu } {\ell} {\nu } $ as a function of $\kappa _{\lambda }$ (top) and $\kappa _{t}$ (bottom). The $\kappa _{\lambda }$ ($\kappa _{t}$) scans are performed assuming $c_{2} =0$, $c_{g} = 0$, and $c_{2g} = 0$, while $\kappa _{t} = 1$ ($\kappa _{\lambda } =1$). These limits are computed using the asymptotic CL$_s$ method. Theory predictions are extracted from [9,10,11,12,13,14,54]. 
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Figure 5b:
Expected and observed 95% CL upper limits on the Higgs pair production cross section times branching fraction for $ {\mathrm {h}} {\mathrm {h}} \to { {\mathrm {b}} {\overline {\mathrm {b}}} } {\mathrm {V}} {\mathrm {V}} \to { {\mathrm {b}} {\overline {\mathrm {b}}} } {\ell} {\nu } {\ell} {\nu } $ as a function of $\kappa _{\lambda }$ (top) and $\kappa _{t}$ (bottom). The $\kappa _{\lambda }$ ($\kappa _{t}$) scans are performed assuming $c_{2} =0$, $c_{g} = 0$, and $c_{2g} = 0$, while $\kappa _{t} = 1$ ($\kappa _{\lambda } =1$). These limits are computed using the asymptotic CL$_s$ method. Theory predictions are extracted from [9,10,11,12,13,14,54]. 
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Figure 6a:
Allowed (empty halfcircles) and excluded (solid halfcircles) points of the BSM parameter space at expected and observed 95% CL in the $\kappa _{\lambda }$ vs $\kappa _{t}$ plane. Theoretical crosssection times branching fraction isolines for $ {\mathrm {h}} {\mathrm {h}} \to { {\mathrm {b}} {\overline {\mathrm {b}}} } {\mathrm {V}} {\mathrm {V}} \to { {\mathrm {b}} {\overline {\mathrm {b}}} } {\ell} {\nu } {\ell} {\nu } $ are shown as dashed lines. Other BSM couplings are set to their (null) SM value in the upper figure, and to $c_{2} =3$, $c_{g} = 0$, and $c_{2g} = 0$ in the bottom figure. The limits are computed using the asymptotic CL$_s$ method. Theory predictions are extracted from [9,10,11,12,13,14,54]. 
png pdf 
Figure 6b:
Allowed (empty halfcircles) and excluded (solid halfcircles) points of the BSM parameter space at expected and observed 95% CL in the $\kappa _{\lambda }$ vs $\kappa _{t}$ plane. Theoretical crosssection times branching fraction isolines for $ {\mathrm {h}} {\mathrm {h}} \to { {\mathrm {b}} {\overline {\mathrm {b}}} } {\mathrm {V}} {\mathrm {V}} \to { {\mathrm {b}} {\overline {\mathrm {b}}} } {\ell} {\nu } {\ell} {\nu } $ are shown as dashed lines. Other BSM couplings are set to their (null) SM value in the upper figure, and to $c_{2} =3$, $c_{g} = 0$, and $c_{2g} = 0$ in the bottom figure. The limits are computed using the asymptotic CL$_s$ method. Theory predictions are extracted from [9,10,11,12,13,14,54]. 
Tables  
png pdf 
Table 1:
Summary of the systematic uncertainties and their impact range on total background yields and on the SM signal in the final region. 
Summary 
We have presented a search for Higgs boson pair production, hh, where one of the h decays as $\mathrm{h} \to \mathrm{ b \bar{b} }$, and the other as $\mathrm{h} \to \mathrm{V}\mathrm{V} \to \ell\nu \ell\nu$, using LHC protonproton collision data at $\sqrt{s} =$ 13 TeV corresponding to an integrated luminosity of 2.30 fb$^{1}$. Data and standard model predictions are in agreement within uncertainties. For the SM hh hypothesis, the data are observed (expected) to exclude a production cross section times branching ratio of 166.7 (92.8$^{+59.9}_{33.4}$) fb, corresponding to approximately 400 times the SM cross section. Searching for deviations from the SM, upper limits are set on $\mathrm{h}\mathrm{h} \to \mathrm{ b \bar{b} }\mathrm{V}\mathrm{V} \to \mathrm{ b \bar{b} }\ell\nu\ell\nu$ cross section in scenarios considering five anomalous couplings: $\kappa_{\lambda}$, $\kappa_{t}$, $c_{2}$, $c_{g}$, and $c_{2g}$. The search for Higgs boson pair production in the $\mathrm{ b \bar{b} }\ell\nu\ell\nu$ final state is performed for the first time using LHC data. With the present luminosity, the analysis is insensitive to SM hh production but is already excluding some regions of the BSM parameter space. 
Additional Figures  
png pdf 
Additional Figure 1:
Expected and observed 95% CL upper limits on the Higgs pair production cross section times branching fraction for $\mathrm{h} \mathrm{h} \to {\mathrm{ b \bar{b} } } \mathrm {V}\mathrm {V} \to {\mathrm{ b \bar{b} } } \ell \nu \ell \nu $ as a function of $\kappa _{\lambda }$. The scan is performed assuming $\kappa _{\mathrm{ t } } = 1.5, c_{2} = 2$, $c_{\mathrm{g} } = 0$, and $c_{2\mathrm{g} } = 0$, These limits are computed using the asymptotic CL$_s$ method. 
png pdf 
Additional Figure 2:
Expected and observed 95% CL upper limits on the Higgs pair production cross section times branching fraction for $\mathrm{h} \mathrm{h} \to {\mathrm{ b \bar{b} } } \mathrm {V}\mathrm {V} \to {\mathrm{ b \bar{b} } } \ell \nu \ell \nu $ as a function of $c_{2}$. The scan is performed assuming $\kappa _{\lambda } = 1, \kappa _{\mathrm{ t } } = 1, c_{\mathrm{g} } = 0$, and $c_{2\mathrm{g} } = 0$, These limits are computed using the asymptotic CL$_s$ method. 
png pdf 
Additional Figure 3:
Expected and observed 95% CL upper limits on the Higgs pair production cross section times branching fraction for $\mathrm{h} \mathrm{h} \to {\mathrm{ b \bar{b} } } \mathrm {V}\mathrm {V} \to {\mathrm{ b \bar{b} } } \ell \nu \ell \nu $ as a function of $c_{\mathrm{g} }$. The scan is performed assuming $\kappa _{\lambda } = 1, \kappa _{\mathrm{ t } } = 1, c_{2} = 0$, and $c_{2\mathrm{g} } = 0$, These limits are computed using the asymptotic CL$_s$ method. 
png pdf 
Additional Figure 4:
Expected and observed 95% CL upper limits on the Higgs pair production cross section times branching fraction for $\mathrm{h} \mathrm{h} \to {\mathrm{ b \bar{b} } } \mathrm {V}\mathrm {V} \to {\mathrm{ b \bar{b} } } \ell \nu \ell \nu $ as a function of $c_{2\mathrm{g} }$. The scan is performed assuming $\kappa _{\lambda } = 1, \kappa _{\mathrm{ t } } = 1, c_{2} = 0$, and $c_{\mathrm{g} } = 0$, These limits are computed using the asymptotic CL$_s$ method. 
png pdf 
Additional Figure 5:
Expected and observed 95% CL upper limits on the Higgs pair production cross section times branching fraction for $\mathrm{h} \mathrm{h} \to {\mathrm{ b \bar{b} } } \mathrm {V}\mathrm {V} \to {\mathrm{ b \bar{b} } } \ell \nu \ell \nu $ for each benchmark of the analysis, in addition to the SM case. These limits are computed using the asymptotic CL$_s$ method. 
png pdf 
Additional Figure 6:
Expected and observed 95% CL upper limits on the Higgs pair production cross section times branching fraction for $\mathrm{h} \mathrm{h} \to {\mathrm{ b \bar{b} } } \mathrm {V}\mathrm {V} \to {\mathrm{ b \bar{b} } } \ell \nu \ell \nu $ for each benchmark of the analysis, in addition to the SM case. These limits are computed using the asymptotic CL$_s$ method. 
Additional Material  
Complete set of results for expected and observed 95% CL upper limits on the Higgs pair production cross section times branching fraction 
The complete set of results consist of the experimental observations for all 1459 points of the parameter space that were studied. The results are available both in


Note that:

Please find below an excerpt of the file in JSON format:

Please find below an excerpt of the file in CSV format:

ResultsComplete set of results for expected and observed 95% CL upper limits on the Higgs pair production cross section times branching fraction

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