Measurements of the properties of the new boson with a mass near 125 GeV

This is a condensed description with plots for the analysis CMS-PAS-HIG-13-005.

Sensitivities and significances of the observed excess in the individual decay modes

  Significance (mH = 125.7 GeV)
Combination Expected (pre-fit) Expected (post-fit) Observed
H→ZZ 7.1 σ 7.1 σ 6.7 σ
H→γγ 4.2 σ 3.9 σ 3.2 σ
H→WW 5.6 σ 5.3 σ 3.9 σ
H→bb 2.1 σ 2.2 σ 2.0 σ
H→ττ 2.7 σ 2.6 σ 2.8 σ
H→ττ and H→bb 3.5 σ 3.4 σ 3.4 σ

The expected significance is computed for the background + SM signal hypothesis (with μ=1). The pre-fit expected significance is computed for the nominal value of the nuisance parameters, while the post-fit expected significance is computed setting the nuisance parameters to their best-fit values.

Mass of the observed state

Plot Caption
(Left) 1D test statistics q(mH) scan vs hypothesized Higgs boson mass mH for the γγ and 4l final states separately and for their combination. In this combination, three independent signal strengths gg → H → γγ, VBF+VH → H → γγ, and H → ZZ → 4l are profiled together with all other nuisance parameters.
(Right) 2D 68% CL contours for a hypothesized Higgs boson mass mH and signal strength σ/σSM for the γγ and 4l, and their combination. In this combination, the relative signal strengths are constrained by the expectations for the SM Higgs boson.
1D test statistics q(mH) scan vs hypothesized Higgs boson mass mH for the combination of the high resolution channels. 1D-scans of the test statistic q(mX) versus hypothesized boson mass mX for the combination of the γγ and 4l final states. The solid line is obtained with all nuisance parameters profiled and, hence, includes both statistical and systematic uncertainties. The dashed line is obtained with all nuisance parameters fixed to their best-fit values and, hence, includes only statistical uncertainties. The crossings with the thick (thin) horizontal lines define the 68% (95%) CL interval for the measured mass.

Additional plots

Plot Caption
\ 1D test statistics –2 ln Q vs hypothesized Higgs boson mass mH for the diphoton final state. The solid line is obtained with all nuisance parameters profiled and, hence, includes both statistical and systematic uncertainties. The dashed line is obtained with all nuisance parameters fixed to their best-fit values and, hence, includes only statistical uncertainties. The crossings with the thick (thin) horizontal lines define the 68% (95%) CL interval for the measured mass.
\ 1D test statistics –2 ln Q vs hypothesized Higgs boson mass mH for the four-lepton final state. The solid line is obtained with all nuisance parameters profiled and, hence, includes both statistical and systematic uncertainties. The dashed line is obtained with all nuisance parameters fixed to their best-fit values and, hence, includes only statistical uncertainties. The crossings with the thick (thin) horizontal lines define the 68% (95%) CL interval for the measured mass.
2D test statistics –2 ln Q vs hypothesized Higgs boson mass mH and signal strength σ/σSM for the combination of the high resolution channels. The cross indicates the best-fit values. The solid, dashed, and dotted contours show the 68%, 95%, and 99.7% CL ranges, respectively. In this combination, the relative signal strengths for the various final states are constrained by the expectations for the SM Higgs boson.
2D test statistics –2 ln Q vs hypothesized Higgs boson mass mH and signal strength σ/σSM for the diphoton final state. The cross indicates the best-fit values. The solid, dashed, and dotted contours show the 68%, 95%, and 99.7% CL ranges, respectively. In this combination, the relative signal strengths for the various production modes are constrained by the expectations for the SM Higgs boson.
2D test statistics –2 ln Q vs hypothesized Higgs boson mass mH and signal strength σ/σSM for the four-lepton final state. The cross indicates the best-fit values. The solid, dashed, and dotted contours show the 68%, 95%, and 99.7% CL ranges, respectively.

Compatibility of the observed state with the SM Higgs boson hypothesis: signal strengths

Plot Caption
Values of μ̂ = σ/σSM for the combination (solid vertical line) and for contributing channels (points). The vertical band shows the overall μ̂ value 0.80 ± 0.14. The horizontal bars indicate the ±1σ uncertainties on the μ̂ values for individual channels; they include both statistical and systematic uncertainties.
Values of μ̂ = σ/σSM for the combination (solid vertical line) and for sub-combinations grouped by decay mode (points). The vertical band shows the overall μ̂ value 0.80 ± 0.14. The horizontal bars indicate the ±1σ uncertainties on the μ̂ values for individual channels; they include both statistical and systematic uncertainties.
Values of μ̂ = σ/σSM for the combination (solid vertical line) and for sub-combinations grouped by a signature enhancing specific production mechanisms (points). The vertical band shows the overall μ̂ value 0.80 ± 0.14. The horizontal bars indicate the ±1σ uncertainties on the μ̂ values for individual channels; they include both statistical and systematic uncertainties.
(Left plot) The 68% CL intervals for signal strength in the gluon-gluon-fusion-plus-ttH and in VBF-plus-VH production mechanisms: μggH,ttH and μ VBF,VH, respectively. The different colors show the results obtained by combining data from each of the five analayzed decay modes: γγ (green), WW (blue), ZZ(red), ττ (violet), bb (cyan). The crosses indicate the best-fit values. The diamond at (1,1) indicates the expected values for the SM Higgs boson.

Additional plots not in PAS

Plot Caption
Values of μ̂ = σ/σSM for the the individual channels. The horizontal bars indicate the ±1σ uncertainties on the μ̂ values for individual channels; they include both statistical and systematic uncertainties. The vertical dashed line indicates the prediction for a SM Higgs boson.
Values of μ̂ = σ/σSM for the sub-combinations by decay mode. The horizontal bars indicate the ±1σ uncertainties on the μ̂ values for individual channels; they include both statistical and systematic uncertainties. The vertical dashed line indicates the prediction for a SM Higgs boson.
Values of μ̂ = σ/σSM for the sub-combinations grouped by a signature enhancing specific production mechanisms. The horizontal bars indicate the ±1σ uncertainties on the μ̂ values for individual channels; they include both statistical and systematic uncertainties. The vertical dashed line indicates the prediction for a SM Higgs boson.

Numeric values

The tables below contain the same information that is shown in figures 3a-3c of the HIG-13-005 PAS.

Channel μ̂ = σ/σSM (mH = 125.7 GeV)
by production tag and decay mode value uncertainty
H → bb (VH tag) 1.306 -0.608 / +0.682
H → bb (ttH tag) -0.150 -2.903 / +2.820
H → γγ (untagged) 0.700 -0.289 / +0.326
H → γγ (VBF tag) 1.010 -0.535 / +0.628
H → γγ (VH tag) 0.571 -1.135 / +1.340
H → WW (VBF tag) -0.047 -0.555 / +0.747
H → WW (0/1 jet) 0.725 -0.197 / +0.220
H → WW (VH tag) 0.510 -0.942 / +1.256
H → ττ (0/1 jet) 0.770 -0.551 / +0.577
H → ττ (VBF tag) 1.423 -0.637 / +0.696
H → ττ (VH tag) 0.981 -1.496 / +1.680
H → ZZ (0/1 jet) 0.858 -0.258 / +0.321
H → ZZ (2 jets) 1.235 -0.583 / +0.852
by decay mode value uncertainty
H → bb 1.148 -0.595 / +0.646
H → ττ 1.100 -0.397 / +0.432
H → γγ 0.772 -0.259 / +0.289
H → WW 0.679 -0.186 / +0.205
H → ZZ 0.919 -0.247 / +0.301
by production tag value uncertainty
Untagged 0.779 -0.150 / +0.169
VBF tag 1.017 -0.312 / +0.357
VH tag 1.020 -0.468 / +0.503
ttH tag -0.150 -2.903 / +2.820

Production modes

Likelihood scan results for a fit to the data assuming independent signal strengths for each of the four production modes, while the decay branching fractions are assumed to be as in the SM.

Plot Caption
1D test statistics q(μggH) scan vs the signal strength modifier for gluon-fusion production μggH, profiling the signal strength modifiers for the other production modes μVBFVHttH and all other nuisances. The decay branching fractions are assumed to be as in the SM.
1D test statistics q(μVBF) scan vs the signal strength modifier for vector-boson-fusion production μVBF, profiling the signal strength modifiers for the other production modes μggHVHttH and all other nuisances. The decay branching fractions are assumed to be as in the SM.
1D test statistics q(μVH) scan vs the signal strength modifier for associated VH production μVH, profiling the signal strength modifiers for the other production modes μggHVBFttH and all other nuisances. The decay branching fractions are assumed to be as in the SM.

Impact of theoretical uncertainties on inclusive production cross sections (not in PAS)

Likelihood scan results for a fit to the data assuming independent signal strengths for each of the four production modes, while the decay branching fractions are assumed to be as in the SM. Results are shown with and without the theoretical uncertainties from higher order terms on inclusive production cross sections; acceptance, jet-bin, PDF and underlying-event uncertainties are always included.

Plot Caption
1D test statistics q(μggH) scan vs the signal strength modifier for gluon-fusion production μggH, profiling the signal strength modifiers for the other production modes μVBFVHttH and all other nuisances. The decay branching fractions are assumed to be as in the SM.
1D test statistics q(μVBF) scan vs the signal strength modifier for vector-boson-fusion production μVBF, profiling the signal strength modifiers for the other production modes μggHVHttH and all other nuisances. The decay branching fractions are assumed to be as in the SM.
1D test statistics q(μVH) scan vs the signal strength modifier for associated VH production μVH, profiling the signal strength modifiers for the other production modes μggHVBFttH and all other nuisances. The decay branching fractions are assumed to be as in the SM.

Ratio of production modes (not in PAS)

Likelihood scan results for a fit to the data of the ratio of signal strengths in associated VBF and VH production (μVBF,VH) and the other productions modes (μggH,ttH). Using this ratio (μVBF,VHggH,ttH) the branching fractions fractions cancel out in each decay channel and the results of the different channels can be combined.

The best-fit μVBF,VHggH,ttH = 1.538+1.161-0.743 for a 3.21 standard deviation significance against a zero ratio.

Plot Caption
1D test statistics q(μVBF,VHggH,ttH) scan vs the ratio of signal strength modifiers μVBF,VHggH,ttH, profiling all other nuisances, for the different decay channels considered and their combination. The cross-section ratios σVBFVH and σggHttH assumed to be as in the SM.
1D test statistics q(μVBF,VHggH,ttH) scan vs the ratio of signal strength modifiers μVBF,VHggH,ttH, profiling all other nuisances, for the combination of different decay channels as well as the SM expectation. The cross-section ratios σVBFVH and σggHttH assumed to be as in the SM.

Tests for deviations of the couplings

Test of Fermion and Vector Boson Couplings

Plot Caption
2D test statistics q(κV, κF) scan.
2D test statistics q(κV, κF) scan, including individual channels.

Additional plots not in PAS

1D test statistics q(κV) scan, profiling κF.
1D test statistics q(κF) scan, profiling κV.
1D test statistics q(κV) scan, if κF is fixed to the SM value (κF=1).
1D test statistics q(κF) scan, if κV is fixed to the SM value (κV=1).

Test of Custodial Symmetry

Using only untagged WW and ZZ events and assuming SM couplings to fermions

Plot Caption
1D test statistics q(λWZ) scan vs the coupling modifier ratio λWZ, profiling the coupling modifier κZ and all other nuisances. The coupling to fermions is taken to be the SM one (κF = 1).

Additional correlation plot not in PAS

Plot Caption
2D test statistics q(λWZ, κZ) scan, profiling κF and all other nuisances. The coupling to fermions is taken to be the SM one (κF = 1).

Using all channels, and without assumption on the couplings to fermions (except their universality)

Plot Caption
1D test statistics q(λWZ) scan vs the coupling modifier ratio λWZ, profiling the coupling modifiers κZ and κF and all other nuisances.

Additional correlation plots not in PAS

Plot Caption
2D test statistics q(λWZ, κZ) scan, profiling the coupling modifier to fermions κF and all other nuisances.
2D test statistics q(λWZ, κF) scan, profiling the coupling modifier to the Z boson κZ and all other nuisances.

Test of Fermion Universality

Up-type vs Down-type Fermions

Plot Caption
1D test statistics q(λdu) scan vs the coupling modifier ratio λdu, profiling the coupling modifiers κu and κV and all other nuisances. κu and κV are always taken to be positive.

Additional correlation plots not in PAS

Plot Caption
2D test statistics q(λdu, κu) scan, profiling the coupling modifier to vector bosons κV and all other nuisances. κu and κV are always taken to be positive.
2D test statistics q(κV, κu) scan, profiling the modifier to the ratio of up-type and down-type couplings λdu and all other nuisances.

Leptons vs Quarks

Plot Caption
1D test statistics q(λlq) scan vs the coupling modifier ratio λlq, profiling the coupling modifiers κq and κV and all other nuisances. κq and κV are always taken to be positive.

Additional correlation plots not in PAS

Plot Caption
2D test statistics q(λlq, κq) scan, profiling the coupling modifier to vector bosons κV and all other nuisances. κq and κV are always taken to be positive.
2D test statistics q(λlq, κV) scan, profiling the coupling modifier to the quarks κq and all other nuisances. κq and κV are always taken to be positive.
2D test statistics q(κV, κq) scan, profiling the modifier to the ratio of lepton to quark couplings λlq and all other nuisances.

Search for Beyond Standard Model Physics in Loops

Plot Caption
2D test statistics q(κg, κγ) scan.

Additional plots not in PAS

PlotSorted ascending Caption
1D test statistics q(κg) scan, profiling the modifier to the effective coupling to photons κγ.
1D test statistics q(κγ) scan, profiling the modifier to the effective coupling to gluons κg.

Additional plots including Zγ (not in PAS)

For this fit, the Zγ analysis from HIG-13-006 is included, and an extra coupling modifier κ is added to the model to parametrize this loop-induced coupling.
Limits are set in the 2D plane (κγ, κ), profiling the modifier to the gluon effective coupling κg, and assuming the tree-level couplings to be as in the SM (κ = 1).
Plot Caption
2D test statistics q(κg, κ) scan, profiling the modifier to the effective coupling to gluons κg.

Search for Beyond Standard Model Physics in Loops and Decays

Plot Caption
1D test statistics q(BRBSM) scan, profiling the modifier to the effective coupling to photons and gluons κγ, κg.
2D test statistics q(κg, BRBSM) scan, profiling the modifier to the effective coupling to photons κγ.

Generic search for deviations in the couplings (with effective photon and gluon couplings)

The search is performed with five independent coupling modifiers: κV, κb, κτ, κt, κg, κγ.
Plot Caption
1D test statistics q(κV) scan, profiling the other five coupling modifiers.
1D test statistics q(κb) scan, profiling the other five coupling modifiers.
1D test statistics q(κτ) scan, profiling the other five coupling modifiers.
1D test statistics q(κt) scan, profiling the other five coupling modifiers.
1D test statistics q(κγ) scan, profiling the other five coupling modifiers.
1D test statistics q(κg) scan, profiling the other five coupling modifiers.

Including BSM decays

Plot Caption
The likelihood scan versus BRBSM = ΓBSMtot. The solid curve is the data and the dashed line indicates the expected median results in the presence of the SM Higgs boson. The modifiers for both the tree-level and loop-induced couplings are profiled, but the couplings to the electroweak bosons are assumed to be bound by the SM expectation (κV ≤ 1)

Generic search for deviations in the couplings (assuming SM loop structure) (not in PAS)

The search is performed with five independent coupling modifiers: κW, κZ, κb, κτ, κt.

Plot Caption
1D test statistics q(κW) scan, profiling the other four coupling modifiers.
1D test statistics q(κZ) scan, profiling the other four coupling modifiers.
1D test statistics q(κb) scan, profiling the other four coupling modifiers.
1D test statistics q(κτ) scan, profiling the other four coupling modifiers.
1D test statistics q(κt) scan, profiling the other four coupling modifiers.

Summary plots of couplings

Plot Caption
Summary of the fits for deviations in the coupling for the LHC XS WG benchmark models (arXiv:1209.0040). For each model, the best fit values of the most interesting parameters are shown, with the corresponding 68% and 95% CL intervals, and the overall p-value pSM of the SM Higgs hypothesis is given. The list of parameters for each model and the numerical values of the intervals are provided in Table 3 of the PAS.
Summary of the fits for deviations in the coupling for the generic six-parameter model including effective loop couplings. The best fit of the parameters are shown, with the corresponding 68% and 95% CL intervals, and the overall p-value pSM of the SM Higgs hypothesis is given. The result of the fit when extending the model to allow for beyond-SM decays while restricting the effective coupling to vector bosons to not exceed unity (κV ≤ 1.0) is also shown.
Summary of the fits for deviations in the coupling for the generic five-parameter model not effective loop couplings. In this model, loop-induced couplings are assumed to follow the SM structure as in arXiv:1209.0040. The best fit values of the parameters are shown, with the corresponding 68% and 95% CL intervals, and the overall p-value pSM of the SM Higgs hypothesis is given.
Summary of the fits for deviations in the coupling for the generic five-parameter model not effective loop couplings, expressed as function of the particle mass. For the fermions, the values of the fitted yukawa couplings hff are shown, while for vector bosons the square-root of the coupling for the hVV vertex divided by twice the vacuum expectation value of the Higgs boson field. Particle masses (in the MS-bar scheme) and the vacuum expectation value of the Higgs boson are taken from the PDG. In this model, loop-induced couplings are assumed to follow the SM structure as in arXiv:1209.0040.
Summary of the fits for deviations in the coupling for the generic five-parameter model not effective loop couplings, expressed as function of the particle mass. For the fermions, the values of the fitted yukawa couplings hff are shown, while for vector bosons the square-root of the coupling for the hVV vertex divided by twice the vacuum expectation value of the Higgs boson field. Particle masses for leptons and weak boson, and the vacuum expectation value of the Higgs boson are taken from the PDG. For the top quark the same mass used in theoretical calculations is used (172.5 GeV) and for the bottom quark the running mass mb(mH=125.7 GeV)=2.763 GeV is used. In this model, loop-induced couplings are assumed to follow the SM structure as in arXiv:1209.0040.

Combined WW + ZZ results for spin 2

Plot Caption
Post-fit model distributions of the test statistic comparing the signal JP hypotheses 0+ and 2+m(gg) in the best fit to the data.
The observed value is indicated by the arrow and disfavours the 2+m(gg) signal hypothesis with a CLs value of 0.6%.
Pre-fit model distributions of the test statistic comparing the signal JP hypotheses 0+ and 2+m(gg).
The median expected CLs value of the 2+m(gg) hypothesis for a SM Higgs boson is 0.2%.

Additional plots for WW and ZZ alone

Plot Caption
H→ZZ: post-fit model distributions of the test statistic comparing the signal JP hypotheses 0+ and 2+m(gg) in the best fit to the data.
The observed value is indicated by the arrow and disfavours the 2+m(gg) signal hypothesis with a CLs value of 1.3%.
H→ZZ: pre-fit model distributions of the test statistic comparing the signal JP hypotheses 0+ and 2+m(gg).
The median expected CLs value of the 2+m(gg) hypothesis for a SM Higgs boson is 6.8%.
H→WW: post-fit model distributions of the test statistic comparing the signal JP hypotheses 0+ and 2+m(gg) in the best fit to the data.
The observed value is indicated by the arrow and disfavours the 2+m(gg) signal hypothesis with a CLs value of 14.0%
H→WW: pre-fit model distributions of the test statistic comparing the signal JP hypotheses 0+ and 2+m(gg).
The median expected CLs value of the 2+m(gg) hypothesis for a SM Higgs boson is 1.4%.


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