Figure 01a

Example Feynman diagrams of the probed processes: (a) associated production of a Higgs boson and a Z boson, where the Higgs boson decays into DM particles, (b) production of a Z boson and a mediator from a quark initial state in the simplified DM models, and (c) gg- and (d) bb-initiated 2HDM+a diagrams.

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Figure 01b

Example Feynman diagrams of the probed processes: (a) associated production of a Higgs boson and a Z boson, where the Higgs boson decays into DM particles, (b) production of a Z boson and a mediator from a quark initial state in the simplified DM models, and (c) gg- and (d) bb-initiated 2HDM+a diagrams.

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Figure 01c

Example Feynman diagrams of the probed processes: (a) associated production of a Higgs boson and a Z boson, where the Higgs boson decays into DM particles, (b) production of a Z boson and a mediator from a quark initial state in the simplified DM models, and (c) gg- and (d) bb-initiated 2HDM+a diagrams.

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Figure 01d

Example Feynman diagrams of the probed processes: (a) associated production of a Higgs boson and a Z boson, where the Higgs boson decays into DM particles, (b) production of a Z boson and a mediator from a quark initial state in the simplified DM models, and (c) gg- and (d) bb-initiated 2HDM+a diagrams.

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Figure 02a

Distributions in data compared with simulated events in the different CRs after (a, b, c) the simultaneous ZH→ ℓ ℓ+inv fit and (d) a fit in the context of the simplified DM models (axial-vector signal with (m_χ, m_med) = (150, 900) GeV): (a) E_T^miss distribution in the 3ℓ CR, (b) E_T^miss′ distribution in the 4ℓ CR, (c) BDT distribution in the eμ CR, (d) m_T distribution in the eμ CR. As defined in the text, `Non-res.' includes WW, tt̄, single-top and Z→ττ processes, while `Other' stands for triboson, tt̄+V, and ZZ → 4ℓ production. Events recorded below (above) the x-range of the BDT plot are included in the first (last) bin shown. The bottom panel in each figure shows the ratio of the observed data to the predicted yields. The shaded bands in top and bottom panels represent the total statistical and systematic error of the background.

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Figure 02b

Distributions in data compared with simulated events in the different CRs after (a, b, c) the simultaneous ZH→ ℓ ℓ+inv fit and (d) a fit in the context of the simplified DM models (axial-vector signal with (m_χ, m_med) = (150, 900) GeV): (a) E_T^miss distribution in the 3ℓ CR, (b) E_T^miss′ distribution in the 4ℓ CR, (c) BDT distribution in the eμ CR, (d) m_T distribution in the eμ CR. As defined in the text, `Non-res.' includes WW, tt̄, single-top and Z→ττ processes, while `Other' stands for triboson, tt̄+V, and ZZ → 4ℓ production. Events recorded below (above) the x-range of the BDT plot are included in the first (last) bin shown. The bottom panel in each figure shows the ratio of the observed data to the predicted yields. The shaded bands in top and bottom panels represent the total statistical and systematic error of the background.

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Figure 02c

Distributions in data compared with simulated events in the different CRs after (a, b, c) the simultaneous ZH→ ℓ ℓ+inv fit and (d) a fit in the context of the simplified DM models (axial-vector signal with (m_χ, m_med) = (150, 900) GeV): (a) E_T^miss distribution in the 3ℓ CR, (b) E_T^miss′ distribution in the 4ℓ CR, (c) BDT distribution in the eμ CR, (d) m_T distribution in the eμ CR. As defined in the text, `Non-res.' includes WW, tt̄, single-top and Z→ττ processes, while `Other' stands for triboson, tt̄+V, and ZZ → 4ℓ production. Events recorded below (above) the x-range of the BDT plot are included in the first (last) bin shown. The bottom panel in each figure shows the ratio of the observed data to the predicted yields. The shaded bands in top and bottom panels represent the total statistical and systematic error of the background.

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Figure 02d

Distributions in data compared with simulated events in the different CRs after (a, b, c) the simultaneous ZH→ ℓ ℓ+inv fit and (d) a fit in the context of the simplified DM models (axial-vector signal with (m_χ, m_med) = (150, 900) GeV): (a) E_T^miss distribution in the 3ℓ CR, (b) E_T^miss′ distribution in the 4ℓ CR, (c) BDT distribution in the eμ CR, (d) m_T distribution in the eμ CR. As defined in the text, `Non-res.' includes WW, tt̄, single-top and Z→ττ processes, while `Other' stands for triboson, tt̄+V, and ZZ → 4ℓ production. Events recorded below (above) the x-range of the BDT plot are included in the first (last) bin shown. The bottom panel in each figure shows the ratio of the observed data to the predicted yields. The shaded bands in top and bottom panels represent the total statistical and systematic error of the background.

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Figure 03a

(a) BDT and (b) m_T distributions in the signal region, after the respective simultaneous fits. The H → inv signal, with a branching ratio of B = 100%, is shown in (a) and an example DM axial-vector signal with (m_χ, m_med) = (150, 900) GeV is shown in (b). As defined in the text, `Non-res.' includes WW, tt̄, single top-quark and Z→ττ processes, while `Other' stands for triboson, tt̄+V, and ZZ → 4ℓ production. Events recorded below (above) the x-range of the BDT plot are included in the first (last) bin shown. The bottom panel in each figure shows the ratio of the observed data to the predicted yields. The shaded bands in top and bottom panels represent the total statistical and systematic error of the background.

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Figure 03b

(a) BDT and (b) m_T distributions in the signal region, after the respective simultaneous fits. The H → inv signal, with a branching ratio of B = 100%, is shown in (a) and an example DM axial-vector signal with (m_χ, m_med) = (150, 900) GeV is shown in (b). As defined in the text, `Non-res.' includes WW, tt̄, single top-quark and Z→ττ processes, while `Other' stands for triboson, tt̄+V, and ZZ → 4ℓ production. Events recorded below (above) the x-range of the BDT plot are included in the first (last) bin shown. The bottom panel in each figure shows the ratio of the observed data to the predicted yields. The shaded bands in top and bottom panels represent the total statistical and systematic error of the background.

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Figure 04a

Exclusion limits for simplified DM models with g_χ = 1.0, g_q = 0.25, and g_ℓ = 0, when assuming (a) an axial-vector mediator or (b) a vector mediator. The region below the solid black line is excluded at the 95% CL. The dashed black line indicates the expected limit in the absence of signal, and the yellow band the corresponding ± 1 σ uncertainty band. The dashed red line labelled `Relic density' corresponds to combinations of DM and mediator mass values that are consistent with a DM density of Ω h² = 0.118 and a standard thermal history, as computed in Ref. [13]. Below the line, annihilation processes described by the simplified model mostly predict too high a relic density while regions with too low a relic density are mostly found for m_med closer to the DM mass. The dashed magenta line indicates the previous ATLAS result from a 36.1 fb^-1 dataset [22].

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Figure 04b

Exclusion limits for simplified DM models with g_χ = 1.0, g_q = 0.25, and g_ℓ = 0, when assuming (a) an axial-vector mediator or (b) a vector mediator. The region below the solid black line is excluded at the 95% CL. The dashed black line indicates the expected limit in the absence of signal, and the yellow band the corresponding ± 1 σ uncertainty band. The dashed red line labelled `Relic density' corresponds to combinations of DM and mediator mass values that are consistent with a DM density of Ω h² = 0.118 and a standard thermal history, as computed in Ref. [13]. Below the line, annihilation processes described by the simplified model mostly predict too high a relic density while regions with too low a relic density are mostly found for m_med closer to the DM mass. The dashed magenta line indicates the previous ATLAS result from a 36.1 fb^-1 dataset [22].

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Figure 05a

Exclusion limits within the context of 2HDM+a models with different parameter choices and in various planes [21]. Subfigures (a, b) show the tanβ vs m_a exclusion limits with m_A = 600 GeV, (c, d) the tanβ vs m_A exclusion limits with m_a = 250 GeV, and (e, f) the m_A vs m_a exclusion limit with tanβ = 1.0. The region contained by the solid black line and the hashed black contour is excluded at the 95% CL. The solid blue line indicates the expected limit in the absence of signal, and the dashed blue lines the corresponding ± 1 σ uncertainty band. Subfigures (a, c, e) assume sin θ = 0.35, while (b, d, f) assume sin θ = 0.7. Where included, the dashed magenta lines represent the 36.1 fb^-1 36.1 results from Ref. [26]. The hashed red area indicates that the width of one of the Higgs bosons is larger than 20% of its mass.

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Figure 05b

Exclusion limits within the context of 2HDM+a models with different parameter choices and in various planes [21]. Subfigures (a, b) show the tanβ vs m_a exclusion limits with m_A = 600 GeV, (c, d) the tanβ vs m_A exclusion limits with m_a = 250 GeV, and (e, f) the m_A vs m_a exclusion limit with tanβ = 1.0. The region contained by the solid black line and the hashed black contour is excluded at the 95% CL. The solid blue line indicates the expected limit in the absence of signal, and the dashed blue lines the corresponding ± 1 σ uncertainty band. Subfigures (a, c, e) assume sin θ = 0.35, while (b, d, f) assume sin θ = 0.7. Where included, the dashed magenta lines represent the 36.1 fb^-1 36.1 results from Ref. [26]. The hashed red area indicates that the width of one of the Higgs bosons is larger than 20% of its mass.

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Figure 05c

Exclusion limits within the context of 2HDM+a models with different parameter choices and in various planes [21]. Subfigures (a, b) show the tanβ vs m_a exclusion limits with m_A = 600 GeV, (c, d) the tanβ vs m_A exclusion limits with m_a = 250 GeV, and (e, f) the m_A vs m_a exclusion limit with tanβ = 1.0. The region contained by the solid black line and the hashed black contour is excluded at the 95% CL. The solid blue line indicates the expected limit in the absence of signal, and the dashed blue lines the corresponding ± 1 σ uncertainty band. Subfigures (a, c, e) assume sin θ = 0.35, while (b, d, f) assume sin θ = 0.7. Where included, the dashed magenta lines represent the 36.1 fb^-1 36.1 results from Ref. [26]. The hashed red area indicates that the width of one of the Higgs bosons is larger than 20% of its mass.

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Figure 05d

Exclusion limits within the context of 2HDM+a models with different parameter choices and in various planes [21]. Subfigures (a, b) show the tanβ vs m_a exclusion limits with m_A = 600 GeV, (c, d) the tanβ vs m_A exclusion limits with m_a = 250 GeV, and (e, f) the m_A vs m_a exclusion limit with tanβ = 1.0. The region contained by the solid black line and the hashed black contour is excluded at the 95% CL. The solid blue line indicates the expected limit in the absence of signal, and the dashed blue lines the corresponding ± 1 σ uncertainty band. Subfigures (a, c, e) assume sin θ = 0.35, while (b, d, f) assume sin θ = 0.7. Where included, the dashed magenta lines represent the 36.1 fb^-1 36.1 results from Ref. [26]. The hashed red area indicates that the width of one of the Higgs bosons is larger than 20% of its mass.

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Figure 05e

Exclusion limits within the context of 2HDM+a models with different parameter choices and in various planes [21]. Subfigures (a, b) show the tanβ vs m_a exclusion limits with m_A = 600 GeV, (c, d) the tanβ vs m_A exclusion limits with m_a = 250 GeV, and (e, f) the m_A vs m_a exclusion limit with tanβ = 1.0. The region contained by the solid black line and the hashed black contour is excluded at the 95% CL. The solid blue line indicates the expected limit in the absence of signal, and the dashed blue lines the corresponding ± 1 σ uncertainty band. Subfigures (a, c, e) assume sin θ = 0.35, while (b, d, f) assume sin θ = 0.7. Where included, the dashed magenta lines represent the 36.1 fb^-1 36.1 results from Ref. [26]. The hashed red area indicates that the width of one of the Higgs bosons is larger than 20% of its mass.

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Figure 05f

Exclusion limits within the context of 2HDM+a models with different parameter choices and in various planes [21]. Subfigures (a, b) show the tanβ vs m_a exclusion limits with m_A = 600 GeV, (c, d) the tanβ vs m_A exclusion limits with m_a = 250 GeV, and (e, f) the m_A vs m_a exclusion limit with tanβ = 1.0. The region contained by the solid black line and the hashed black contour is excluded at the 95% CL. The solid blue line indicates the expected limit in the absence of signal, and the dashed blue lines the corresponding ± 1 σ uncertainty band. Subfigures (a, c, e) assume sin θ = 0.35, while (b, d, f) assume sin θ = 0.7. Where included, the dashed magenta lines represent the 36.1 fb^-1 36.1 results from Ref. [26]. The hashed red area indicates that the width of one of the Higgs bosons is larger than 20% of its mass.

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Figure 06a

sinθ exclusion limits for 2HDM+a signals with tanβ = 1.0 and m_χ = 10 GeV. The solid black line shows the observed limit, while the dashed black line indicates the expected limit in the absence of signal, with the corresponding 1σ and 2σ uncertainty bands in green and yellow. The dashed red line shows the result from the 36 fb^-1 analysis [26]. The region below μ^95%_upper = 1 is excluded at the 95% CL. In (a), m_A = 600 GeV and ma = 200 GeV, while in (b) m_A = 1000 GeV and ma = 350 GeV.

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Figure 06b

sinθ exclusion limits for 2HDM+a signals with tanβ = 1.0 and m_χ = 10 GeV. The solid black line shows the observed limit, while the dashed black line indicates the expected limit in the absence of signal, with the corresponding 1σ and 2σ uncertainty bands in green and yellow. The dashed red line shows the result from the 36 fb^-1 analysis [26]. The region below μ^95%_upper = 1 is excluded at the 95% CL. In (a), m_A = 600 GeV and ma = 200 GeV, while in (b) m_A = 1000 GeV and ma = 350 GeV.

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Figure 07

Comparison between the 90% CL upper limits on the spin-independent WIMP--nucleon scattering cross-section from direct-detection experiments [1-5] and a reinterpretation of the B(H → inv) limit obtained in this analysis, as a function of the WIMP mass. Higgs portal scenarios are assumed, where the 125 GeV Higgs boson decays into a pair of DM particles [105] that are either scalars or Majorana fermions. The uncertainties from the nuclear form factor are indicated by the hatched band. The regions above the limit contours are excluded in the σ _WIMP-N range shown in the plot.

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Figure 08a

Comparison of the upper limits at 90% CL from direct-detection experiments [1-8] with the exclusion obtained in the simplified DM models in the plane of the dark matter mass and (a) the spin-dependent WIMP--proton scattering cross-section or (b) the spin-independent WIMP--nucleon scattering cross-section [12]. The area within the shaded lines is excluded by this analysis in the context of the simplified models.

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Figure 08b

Comparison of the upper limits at 90% CL from direct-detection experiments [1-8] with the exclusion obtained in the simplified DM models in the plane of the dark matter mass and (a) the spin-dependent WIMP--proton scattering cross-section or (b) the spin-independent WIMP--nucleon scattering cross-section [12]. The area within the shaded lines is excluded by this analysis in the context of the simplified models.

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