CMS-PAS-FTR-21-004

CMS-PAS-FTR-21-004
Prospects for non-resonant Higgs boson pair production measurement in bb$\gamma\gamma$ final states in proton-proton collisions at $\sqrt{s}=$ 14 TeV at the High-Luminosity LHC
CMS Collaboration
March 2022

Abstract: The nonresonant production of a Higgs boson pair, followed by decays to a pair of bottom quarks and a pair of photons, is studied in the context of the high luminosity operation of the LHC machine. The standard model signal sensitivity is studied with a fast simulation of the Phase-2 upgraded CMS detector with an average of 200 interactions per bunch crossing at $\sqrt{s}=$ 14 TeV and corresponding to an integrated luminosity of 3000 fb$^{-1}$.
Links: CDS record (PDF) ; CADI line (restricted) ;

Figures & Tables	Summary	References	CMS Publications

Figures
png pdf	Figure 1: Representative Feynman diagrams, referred to as the triangle and the box respectively, that contribute to the ggHH production at the leading order in the SM.
png pdf	Figure 1-a: Representative Feynman diagrams, referred to as the triangle and the box respectively, that contribute to the ggHH production at the leading order in the SM.
png pdf	Figure 1-b: Representative Feynman diagrams, referred to as the triangle and the box respectively, that contribute to the ggHH production at the leading order in the SM.
png pdf	Figure 2: Representative Feynman diagrams for the production of Higgs boson pairs via VBF processes at the leading order. The left-most diagram involves the HHH vertex ($\lambda $), the middle one involves HHVV vertex ($C_{2V}$) while the right-most features neither of those couplings, but includes two HVV vertices ($C_{V}$).
png pdf	Figure 2-a: Representative Feynman diagrams for the production of Higgs boson pairs via VBF processes at the leading order. The left-most diagram involves the HHH vertex ($\lambda $), the middle one involves HHVV vertex ($C_{2V}$) while the right-most features neither of those couplings, but includes two HVV vertices ($C_{V}$).
png pdf	Figure 2-b: Representative Feynman diagrams for the production of Higgs boson pairs via VBF processes at the leading order. The left-most diagram involves the HHH vertex ($\lambda $), the middle one involves HHVV vertex ($C_{2V}$) while the right-most features neither of those couplings, but includes two HVV vertices ($C_{V}$).
png pdf	Figure 2-c: Representative Feynman diagrams for the production of Higgs boson pairs via VBF processes at the leading order. The left-most diagram involves the HHH vertex ($\lambda $), the middle one involves HHVV vertex ($C_{2V}$) while the right-most features neither of those couplings, but includes two HVV vertices ($C_{V}$).
png pdf	Figure 3: Distributions of the $ {\mathrm m_{\gamma \gamma}} $ variable for the ggHH- (left) and VBFHH- (right) selected events corresponding to $\mathcal {L} =$ 3000 fb$^{-1}$; ggHH signal (in red), VBFHH signal (in blue) are overlaid on different background processes (filled stacks in different colours).
png pdf	Figure 3-a: Distributions of the $ {\mathrm m_{\gamma \gamma}} $ variable for the ggHH- (left) and VBFHH- (right) selected events corresponding to $\mathcal {L} =$ 3000 fb$^{-1}$; ggHH signal (in red), VBFHH signal (in blue) are overlaid on different background processes (filled stacks in different colours).
png pdf	Figure 3-b: Distributions of the $ {\mathrm m_{\gamma \gamma}} $ variable for the ggHH- (left) and VBFHH- (right) selected events corresponding to $\mathcal {L} =$ 3000 fb$^{-1}$; ggHH signal (in red), VBFHH signal (in blue) are overlaid on different background processes (filled stacks in different colours).
png pdf	Figure 4: Distributions of the $ {\rm m_{\rm bb}} $ variable for the ggHH- (left) and VBFHH- (right) selected events corresponding to $\mathcal {L} =$ 3000 fb$^{-1}$; ggHH signal (in red), VBFHH signal (in blue) are overlaid on different background processes (filled stacks in different colours).
png pdf	Figure 4-a: Distributions of the $ {\rm m_{\rm bb}} $ variable for the ggHH- (left) and VBFHH- (right) selected events corresponding to $\mathcal {L} =$ 3000 fb$^{-1}$; ggHH signal (in red), VBFHH signal (in blue) are overlaid on different background processes (filled stacks in different colours).
png pdf	Figure 4-b: Distributions of the $ {\rm m_{\rm bb}} $ variable for the ggHH- (left) and VBFHH- (right) selected events corresponding to $\mathcal {L} =$ 3000 fb$^{-1}$; ggHH signal (in red), VBFHH signal (in blue) are overlaid on different background processes (filled stacks in different colours).
png pdf	Figure 5: Distributions of the $ {\rm \tilde{M}_X} $ variable for the ggHH- (left) and VBFHH- (right) selected events corresponding to $\mathcal {L} =$ 3000 fb$^{-1}$; ggHH signal (in red), VBFHH signal (in blue) are overlaid on different background processes (filled stacks in different colours).
png pdf	Figure 5-a: Distributions of the $ {\rm \tilde{M}_X} $ variable for the ggHH- (left) and VBFHH- (right) selected events corresponding to $\mathcal {L} =$ 3000 fb$^{-1}$; ggHH signal (in red), VBFHH signal (in blue) are overlaid on different background processes (filled stacks in different colours).
png pdf	Figure 5-b: Distributions of the $ {\rm \tilde{M}_X} $ variable for the ggHH- (left) and VBFHH- (right) selected events corresponding to $\mathcal {L} =$ 3000 fb$^{-1}$; ggHH signal (in red), VBFHH signal (in blue) are overlaid on different background processes (filled stacks in different colours).
png pdf	Figure 6: Distribution of the ggHH-ttHKiller and the VBFHH-ttHKiller discriminant scores for the ggHH- (left) and VBFHH- (right) selected events corresponding to $\mathcal {L} =$ 3000 fb$^{-1}$; ggHH signal (in red), VBFHH signal (in blue) are overlaid on different background processes (filled stacks in different colours).
png pdf	Figure 6-a: Distribution of the ggHH-ttHKiller and the VBFHH-ttHKiller discriminant scores for the ggHH- (left) and VBFHH- (right) selected events corresponding to $\mathcal {L} =$ 3000 fb$^{-1}$; ggHH signal (in red), VBFHH signal (in blue) are overlaid on different background processes (filled stacks in different colours).
png pdf	Figure 6-b: Distribution of the ggHH-ttHKiller and the VBFHH-ttHKiller discriminant scores for the ggHH- (left) and VBFHH- (right) selected events corresponding to $\mathcal {L} =$ 3000 fb$^{-1}$; ggHH signal (in red), VBFHH signal (in blue) are overlaid on different background processes (filled stacks in different colours).
png pdf	Figure 7: Distributions of the ggHH-Tagger and the VBFHH-Tagger discriminant scores for the ggHH- (left) and VBFHH- (right) selected events corresponding to $\mathcal {L} =$ 3000 fb$^{-1}$; ggHH signal (in red), VBFHH signal (in blue) are overlaid on different background processes (filled stacks in different colours).
png pdf	Figure 7-a: Distributions of the ggHH-Tagger and the VBFHH-Tagger discriminant scores for the ggHH- (left) and VBFHH- (right) selected events corresponding to $\mathcal {L} =$ 3000 fb$^{-1}$; ggHH signal (in red), VBFHH signal (in blue) are overlaid on different background processes (filled stacks in different colours).
png pdf	Figure 7-b: Distributions of the ggHH-Tagger and the VBFHH-Tagger discriminant scores for the ggHH- (left) and VBFHH- (right) selected events corresponding to $\mathcal {L} =$ 3000 fb$^{-1}$; ggHH signal (in red), VBFHH signal (in blue) are overlaid on different background processes (filled stacks in different colours).
png pdf	Figure 8: Distributions of the $ {\mathrm m_{\gamma \gamma}} $ (left) and the $ {\rm m_{\rm bb}} $ (right) for the ggHH signal sample in ggHH CAT4 (high $ {\rm \tilde{M}_X} $ and medium purity).
png pdf	Figure 8-a: Distributions of the $ {\mathrm m_{\gamma \gamma}} $ (left) and the $ {\rm m_{\rm bb}} $ (right) for the ggHH signal sample in ggHH CAT4 (high $ {\rm \tilde{M}_X} $ and medium purity).
png pdf	Figure 8-b: Distributions of the $ {\mathrm m_{\gamma \gamma}} $ (left) and the $ {\rm m_{\rm bb}} $ (right) for the ggHH signal sample in ggHH CAT4 (high $ {\rm \tilde{M}_X} $ and medium purity).
png pdf	Figure 9: Distributions of the $ {\mathrm m_{\gamma \gamma}} $ (left) and the $ {\rm m_{\rm bb}} $ (right) for the selected pseudo-data events (black points) corresponding to $\mathcal {L} = $ 3000 fb$^{-1}$ shown for ggHH CAT4 (high $ {\rm \tilde{M}_X} $ and medium purity) along with the expectations as estimated from the simulation. The curves correspond to continuum background only (green dashed), total background (continuum + single Higgs boson) (solid blue), and the signal + background (solid red). The signal contribution is shown in solid magenta line at the bottom of the plot.
png pdf	Figure 9-a: Distributions of the $ {\mathrm m_{\gamma \gamma}} $ (left) and the $ {\rm m_{\rm bb}} $ (right) for the selected pseudo-data events (black points) corresponding to $\mathcal {L} = $ 3000 fb$^{-1}$ shown for ggHH CAT4 (high $ {\rm \tilde{M}_X} $ and medium purity) along with the expectations as estimated from the simulation. The curves correspond to continuum background only (green dashed), total background (continuum + single Higgs boson) (solid blue), and the signal + background (solid red). The signal contribution is shown in solid magenta line at the bottom of the plot.
png pdf	Figure 9-b: Distributions of the $ {\mathrm m_{\gamma \gamma}} $ (left) and the $ {\rm m_{\rm bb}} $ (right) for the selected pseudo-data events (black points) corresponding to $\mathcal {L} = $ 3000 fb$^{-1}$ shown for ggHH CAT4 (high $ {\rm \tilde{M}_X} $ and medium purity) along with the expectations as estimated from the simulation. The curves correspond to continuum background only (green dashed), total background (continuum + single Higgs boson) (solid blue), and the signal + background (solid red). The signal contribution is shown in solid magenta line at the bottom of the plot.

Tables
png pdf	Table 1: Definitions of the analysis categories.
png pdf	Table 2: Sources of experimental uncertainties and impacts on event yields (in %) estimated for the Run 2 [6] studies and used in this analysis.
png pdf	Table 3: Sources of theoretical uncertainties and impacts on event yields (in %) estimated for the Phase-2 studies and used in this analysis according to CERN Yellow Report IV [34].

Summary

The expected signal sensitivity for the standard model production of non-resonant Higgs boson pair in the inclusive bb$\gamma\gamma$ final state is determined to be 2.16$\sigma$. The study has been carried out using Delphes fast simulation of the Phase-2 upgraded CMS detector and corresponding to an average pileup scenario of 200 and integrated luminosity of 3000 fb$^{-1}$ of proton-proton collisions at $\sqrt{s}=$ 14 TeV. Anticipating better analysis techniques and reduced systematic uncertainties, it is expected that the combination of various final states will pave the way for the CMS and ATLAS experiment towards a 5$\sigma$ discovery for the Higgs boson pair production at the HL-LHC.

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