Summary plots from the ATLAS Higgs physics group

Content	Preview
Summary plots from the ATLAS Higgs physics group
Contact: ATLAS Higgs conveners
Higgs mass: Summary of the Higgs boson mass measurements from the individual and combined analyses performed here, compared with the combined Run 1 measurement by ATLAS and CMS [6]. The statistical-only (horizontal yellow-shaded bands) and total (black error bars) uncertainties are indicated. The (red) vertical line and corresponding (grey) shaded column indicate the central value and the total uncertainty of the combined ATLAS Run 1 + 2 measurement, respectively. Reference: Figure 4 in arXiv:1806.00242 png 62kB, pdf 6kB This and previous plot versions
Run 1 Spin/CP: Distributions of the test statistic q for the SM Higgs boson and for the J^P alternative hypotheses. They are obtained by combining the H → ZZ^* → 4 ℓ , H → WW^* → e ν μ ν and H → γ γ decay channels. The expected median (black dashed line) and the ±1, ±2 and ±3 σ regions for the SM Higgs boson (blue) and for the alternative J^P hypotheses (red) are shown for the signal strength fitted to data. The observed q values are indicated by the black points. Reference: Auxiliary Figure 5 in Eur. Phys. J. C75 (2015) 476 png 55kB, pdf 6kB This and previous plot versions
*Total pp → H + X cross section as function of sqrt(s) from H→ γ γ and H→ ZZ^ → 4ℓ*: Total pp → H + X cross sections measured at centre-of-mass energies of 7, 8, and 13 TeV, compared to Standard Model predictions at up to N³LO in QCD. Shown are the measurements in the H→ γ γ channel (red triangles), the H→ ZZ^ → 4ℓ channel (green rectangles), and the combinations of these two channels (black dots). The individual channel results are offset along the x-axis for display purposes. The grey bands on the combined measurements represent the systematic uncertainty, while the error bars show the total uncertainty. The light (dark) blue band shows the estimated uncertainty due to missing higher-order corrections (the total uncertainty). The total theoretical uncertainty corresponds to the higher-order-correction uncertainty summed in quadrature with the sum of the PDF and α_S uncertainties, and is partially correlated across values of the centre-of-mass energy. Reference: Figure 1 in ATLAS-CONF-2017-047 png 24kB, pdf 15kB This and previous plot versions
Run 1 cross section and partial decay width ratios: The gg→ H→ WW^* cross section, ratios of cross sections and of partial decay widths relative to their SM values at m_H=125.36 GeV from the combined analyses of the √s=7 and 8 TeV data. The inner and outer error bars on the measurements are 68% CL and 95% CL intervals. The SM predictions are shown as the vertical line at unity with grey bands representing theoretical uncertainties on the ratios of inclusive cross sections and of partial decay widths. Reference: Figure 6 in Eur. Phys. J. C (2016) 76:6 png 59kB, pdf 93kB This and previous plot versions
Run 2 cross section and partial decay width ratios: Results of a simultaneous fit for σ_ggF^ZZ, σ_VBF/σ_ggF, σ_WH/σ_ggF, σ_ZH/σ_ggF, σ_tt̄H+tH/σ_ggF, B_γγ/B_ZZ, B_WW/B_ZZ, B_ττ/B_ZZ, and B_bb/B_ZZ. The fit results are normalized to the SM predictions. The black error bars, blue boxes and yellow boxes show the total, systematic, and statistical uncertainties in the measurements, respectively. The grey bands show the theory uncertainties in the predictions.Reference: Figure 6 in ATLAS-CONF-2018-031 png 115kB, pdf 16kB This and previous plot versions
Run 2 cross sections: Cross-sections for ggF, VBF, WH, ZH and tt̄H+tH normalized to their SM predictions, measured with the assumption of SM branching fractions. The black error bars, blue boxes and yellow boxes show the total, systematic, and statistical uncertainties in the measurements, respectively. The grey bands indicate the theory uncertainties in the cross-section predictions. Reference: Figure 2 in ATLAS-CONF-2018-031 png 45kB, pdf 15kB This and previous plot versions
Run 1 signal strength in decay modes: The observed signal strengths and uncertainties for different Higgs boson decay channels and their combination for m_H=125.36 GeV. Higgs boson signals corresponding to the same decay channel are combined together for all analyses, assuming SM values for the cross-section ratios of different production processes. The best-fit values are shown by the solid vertical lines. The total ±1σ uncertainties are indicated by green shaded bands, with the individual contributions from the statistical uncertainty (top), the total (experimental and theoretical) systematic uncertainty (middle), and the signal theoretical uncertainty (bottom) on the signal strength shown as horizontal error bars. Reference: Figure 2 in Eur. Phys. J. C (2016) 76:6 png 91kB, pdf 18kB This and previous plot versions
Run 1 signal strength in decay modes (simple version): The observed and expected signal strengths and uncertainties for different Higgs boson decay channels and their combination for m_H=125.36 GeV. Higgs boson signals of the same decay in all analyses are combined together. The best-fit values are shown by the solid vertical lines. The observed total ±1σ uncertainties are indicated by green shaded bands and blue error bars, whereas the expected ±1σ total uncertainties are indicated by red error bars, centered at the expected signal strength of 1. Reference: Auxiliary Figure 7 in Eur. Phys. J. C (2016) 76:6 png 143kB, pdf 17kB This and previous plot versions
Run 1 signal strength in production modes: The best-fit signal-strength values of different production modes determined from the combined fit to the √s=7 and 8 TeV data. The inner and outer error bars correspond to 68% CL and 95% CL intervals. Total uncertainties combining statistical, experimental and theoretical systematic uncertainties are shown. The fit assumes the SM values of the Higgs boson decay branching ratios for m_H=125.36 GeV. Reference: Figure 3 in Eur. Phys. J. C (2016) 76:6 png 34kB, pdf 89kB This and previous plot versions
Run 2 kF vs kV coupling strength: Observed contours at 68% and 95% CL in the (κ_F, κ_V) plane, defined in the asymptotic approximation by -2logΛ = 2.28 and 5.99, respectively, for individual channels and the combined fit. The crosses indicate the best-fit values and the star the SM prediction. Reference: Figure 8 in ATLAS-CONF-2018-031 png 30kB, pdf 20kB This and previous plot versions
Run 2 coupling strength: Best-fit values and uncertainties of Higgs boson coupling modifiers per particle type with effective photon and gluon couplings and either B_BSM = 0 (left), or B_BSM included as a free parameter (right). The SM corresponds to B_BSM = 0 and all κ parameters set to unity. All parameters except κ_t are assumed to be positive. In the model with B_BSM included as a free parameter, the conditions κ_W,Z ≤ 1 are also applied and an upper limit on B_BSM is reported. Reference: Figure 11 in ATLAS-CONF-2018-031 png 36kB, pdf 15kB This and previous plot versions
Run 2 coupling strength ratios: Measured ratios of coupling modifiers. The dashed line indicates the SM value of unity for each parameter. Reference: Figure 12 in ATLAS-CONF-2018-031 png 28kB, pdf 14kB This and previous plot versions
Run 2 coupling strengths vs particle mass: Reduced coupling strength modifiers κ_Fm_F/v for fermions (F = t, b, τ, μ) and √κ_Vm_V/v for weak gauge bosons (V = W, Z) as a function of their masses m_F and m_V, respectively, and the vacuum expectation value of the Higgs field v = 246 GeV. The SM prediction for both cases is also shown (dotted line). The couplings modifiers κ_F and κ_V are measured assuming no BSM contributions to the Higgs boson decays, and the SM structure of loop processes such as ggF, H→γγ and H→gg. Reference: Figure 10 in ATLAS-CONF-2018-031 png 42kB, pdf 15kB This and previous plot versions
BSM Higgs exclusion in the hMSSM: Regions of the [m_A, tanβ] plane excluded in the hMSSM model via direct searches for heavy Higgs bosons and fits to the measured rates of observed Higgs boson production and decays. Limits are quoted at 95% CL and are indicated for the data (solid lines) and the expectation for the SM Higgs sector (dashed lines). The light shaded or hashed regions indicate the observed exclusions. The cross sections for the Higgs boson production in the hMSSM [Eur. Phys. J. C73, 2650,JHEP 06, 168(2015)] are calculated using up to NNLO QCD corrections for gluon-gluon fusion and b-associated production in the five-flavour scheme as implemented in `Sushi` [Comput. Phys. Commun., 184:1605-1617,JHEP 12, 015(2015),Phys. Rev. D 68, 013001,Phys. Rev. Lett. 88, 201801]. For b-associated production a cross section in the four-flavour scheme is calculated as described in Refs. [Phys. Rev. D 69, 074027,Phys. Rev. D 70, 074010] and the results are combined with the five-flavour scheme calculation following Ref. [arXiv:1112.3478 (hep-ph)]. The Higgs boson widths and branching ratios have been calculated using `HDECAY` [Comput. Phys. Commun., 108:56-74]. The procedure for the calculation of the cross sections and the branching ratios follows Ref. [arXiv:1610.07922 (hep-ph)]. Observed limits only Expected limits only png 201kB, pdf 25kB, eps 41kB This and previous plot versions
BSM Higgs exclusion in the hMSSM (large m_A range): Regions of the [m_A, tanβ] plane excluded in the hMSSM model via direct searches for heavy Higgs bosons and fits to the measured rates of observed Higgs boson production and decays. Limits are quoted at 95% CL and are indicated for the data (solid lines) and the expectation for the SM Higgs sector (dashed lines). The light shaded or hashed regions indicate the observed exclusions. The cross sections for the Higgs boson production in the hMSSM [Eur. Phys. J. C73, 2650,JHEP 06, 168(2015)] are calculated using up to NNLO QCD corrections for gluon-gluon fusion and b-associated production in the five-flavour scheme as implemented in `Sushi` [Comput. Phys. Commun., 184:1605-1617,JHEP 12, 015(2015),Phys. Rev. D 68, 013001,Phys. Rev. Lett. 88, 201801]. For b-associated production a cross section in the four-flavour scheme is calculated as described in Refs. [Phys. Rev. D 69, 074027,Phys. Rev. D 70, 074010] and the results are combined with the five-flavour scheme calculation following Ref. [arXiv:1112.3478 (hep-ph)]. The Higgs boson widths and branching ratios have been calculated using `HDECAY` [Comput. Phys. Commun., 108:56-74]. The procedure for the calculation of the cross sections and the branching ratios follows Ref. [arXiv:1610.07922 (hep-ph)]. png 188kB, pdf 25kB, eps 38kB This and previous plot versions
Summary of HH results: The 95% C.L. upper limit of Higgs boson pair (HH) production normalized by the SM prediction for gluon–gluon fusion produced HH of σ_SM (pp → HH) = 33.41 fb, which is calculated with m_H = 125.09 GeV at next-to-leading order in QCD considering the full top-quark mass dependence in Ref. [Phys. Rev. Lett. 117 (2016) 012001 , Phys. Rev. Lett. 117 (2016) 079901 (Err.)]. The upper limits are obtained separately from several final states of HH decaying to bb̅τ⁺τ^-, bb̅bb̅, bb̅γγ and W⁺W^-γγ. png 31kB, pdf 17kB This and previous plot versions

ATLAS Collaboration, 2019