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| CMS-PAS-HIG-16-033 | ||
| Measurements of properties of the Higgs boson and search for an additional resonance in the four-lepton final state at $\sqrt{s} =$ 13 TeV | ||
| CMS Collaboration | ||
| August 2016 | ||
| Abstract: Studies of Higgs boson properties are presented using the ${\rm H}\rightarrow{\rm Z}{\rm Z}\rightarrow4\ell$ ($\ell={\rm e},\mu$) decay channel. These studies are performed using a data sample corresponding to an integrated luminosity of 12.9 fb$^{-1}$ of pp collisions at a center-of-mass energy of 13 TeV collected by the CMS experiment at the LHC during 2016. The observed significance for the standard model Higgs boson with $m_{{\rm H}}=$ 125.09 GeV is 6.2$\sigma$, where the expected significance is 6.5$\sigma$. The signal strength modifier $\mu$, defined as the production cross section of the Higgs boson times its branching fraction to four leptons relative to the standard model expectation, is measured to be $\mu=$ 0.99$^{+0.33}_{-0.26}$ at $m_{\rm H}=$ 125.09 GeV. The signal-strength modifiers for the main Higgs boson production modes have also been constrained. The model independent fiducial cross section is measured to be 2.29$^{+0.74}_{-0.64}$ (stat) $^{+0.30}_{-0.23}$ (syst) $^{+0.01}_{-0.05}$ (model dep.) fb and differential cross sections as a function of the $p_{\rm T}$ of the Higgs boson and the number of associated jets are determined. The mass is measured to be $m_{{\rm H}}=$ 124.50$^{+0.48}_{-0.46}$ GeV and the width is constrained to be $\Gamma_{{\rm H}}< $ 41 MeV. The anomalous effects in the Higgs interactions with a pair of Z bosons are constrained under the assumption of a spin-zero resonance. Finally, a search for an additional resonance decaying to ZZ is performed for a range of masses up to 2.5 TeV and with various widths and no significant excess is observed. | ||
| Links: CDS record (PDF) ; inSPIRE record ; CADI line (restricted) ; | ||
| Figures & Tables | Summary | Additional Figures & Material | References | CMS Publications |
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| Figures | |
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Figure 1:
Signal relative purity of the six event categories in terms of the 5 main production mechanisms of the H(125) boson in a 118 $< {m_{4\ell }}<$ 130 GeV window. The $ { {\mathrm {W}} {\mathrm {H}} }$, $ { {\mathrm {Z}} {\mathrm {H}} }$ and $ { {\mathrm {t}}\bar{ \mathrm {t} } {\mathrm {H}} }$ processes are split according to the decay of associated objects, whereby X denotes anything else than a lepton. |
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Figure 2:
Comparison between the observed data and MC prediction in the 2P2F (top left), 3P1F (top right), ${\rm 2P2L_{SS}}$ (bottom left) control regions. The MC prediction is not used in the analysis and is only shown for comparison. Bottom right: combination of the OS and SS method predictions for the reducible background in the signal region and the parametrized $m_{4\ell }$ shape. The yellow band shows the total uncertainty on the prediction. |
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Figure 2-a:
Comparison between the observed data and MC prediction in the 2P2F control region. The MC prediction is not used in the analysis and is only shown for comparison. |
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Figure 2-b:
Comparison between the observed data and MC prediction in the 3P1F control region. The MC prediction is not used in the analysis and is only shown for comparison. |
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Figure 2-c:
Comparison between the observed data and MC prediction in the ${\rm 2P2L_{SS}}$ control region. The MC prediction is not used in the analysis and is only shown for comparison. |
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Figure 2-d:
Combination of the OS and SS method predictions for the reducible background in the signal region and the parametrized $m_{4\ell }$ shape. The yellow band shows the total uncertainty on the prediction. |
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Figure 3:
Distribution of the four-lepton reconstructed invariant mass $ {m_{4\ell }}$ in the full mass range (top) and the low-mass range (bottom left) and high-mass range (bottom right). Points with error bars represent the data and stacked histograms represent expected distributions. The 125 GeV Higgs boson signal and the ZZ backgrounds are normalized to the SM expectation, the Z+X background to the estimation from data. No events are observed with $ {m_{4\ell }}> $ 850 GeV. |
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Figure 3-a:
Distribution of the four-lepton reconstructed invariant mass $ {m_{4\ell }}$ in the full mass range. Points with error bars represent the data and stacked histograms represent expected distributions. The 125 GeV Higgs boson signal and the ZZ backgrounds are normalized to the SM expectation, the Z+X background to the estimation from data. No events are observed with $ {m_{4\ell }}> $ 850 GeV. |
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Figure 3-b:
Distribution of the four-lepton reconstructed invariant mass $ {m_{4\ell }}$ in the low-mass range. Points with error bars represent the data and stacked histograms represent expected distributions. The 125 GeV Higgs boson signal and the ZZ backgrounds are normalized to the SM expectation, the Z+X background to the estimation from data. No events are observed with $ {m_{4\ell }}> $ 850 GeV. |
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Figure 3-c:
Distribution of the four-lepton reconstructed invariant mass $ {m_{4\ell }}$ in the high-mass range. Points with error bars represent the data and stacked histograms represent expected distributions. The ZZ backgrounds are normalized to the SM expectation, the Z+X background to the estimation from data. No events are observed with $ {m_{4\ell }}> $ 850 GeV. |
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Figure 4:
Distribution of the $ {\mathrm {Z}}_1$ (left) and $ {\mathrm {Z}}_2$ (center) reconstructed invariant masses and correlation between the two (right) in the mass region 118 $< {m_{4\ell }}< $ 130 GeV. The stacked histograms and the gray scale represent expected distributions, and points represent the data. The 125 GeV Higgs boson signal and the ZZ backgrounds are normalized to the SM expectation, the Z+X background to the estimation from data. |
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Figure 4-a:
Distribution of the $ {\mathrm {Z}}_1$ reconstructed invariant mass in the mass region 118 $< {m_{4\ell }}< $ 130 GeV. The stacked histograms represent expected distributions, and points represent the data. The 125 GeV Higgs boson signal and the ZZ backgrounds are normalized to the SM expectation, the Z+X background to the estimation from data. |
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Figure 4-b:
Distribution of the $ {\mathrm {Z}}_2$ reconstructed invariant mass in the mass region 118 $< {m_{4\ell }}< $ 130 GeV. The stacked histograms represent expected distributions, and points represent the data. The 125 GeV Higgs boson signal and the ZZ backgrounds are normalized to the SM expectation, the Z+X background to the estimation from data. |
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Figure 4-c:
Correlation between the $ {\mathrm {Z}}_1$ and $ {\mathrm {Z}}_2$ reconstructed invariant masses in the mass region 118 $< {m_{4\ell }}< $ 130 GeV. The gray scale represents expected distributions, and points represent the data. The 125 GeV Higgs boson signal and the ZZ backgrounds are normalized to the SM expectation, the Z+X background to the estimation from data. |
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Figure 5:
Left: Distribution of the kinematic discriminant $ {{\cal D}^{\rm kin}_{\rm bkg}} $ in the mass region 118 $< {m_{4\ell }}< $ 130 GeV. Points with error bars represent the data and stacked histograms represent expected distributions. The 125 GeV Higgs boson signal and the ZZ backgrounds are normalized to the SM expectation, the Z+X background to the estimation from data. Right: Distribution of $ {{\cal D}^{\rm kin}_{\rm bkg}} $ versus $ {m_{4\ell }}$ in the mass region 100 $ < {m_{4\ell }}< $ 170 GeV. The gray scale represents the expected relative density of ZZ background plus Higgs boson signal for $ {m_{ {\mathrm {H}} }}=$ 125 GeV. The points show the data and the horizontal bars represent the measured event-by-event mass uncertainties. Different marker styles are used to denote the categorization of the events. |
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Figure 5-a:
Distribution of the kinematic discriminant $ {{\cal D}^{\rm kin}_{\rm bkg}} $ in the mass region 118 $< {m_{4\ell }}< $ 130 GeV. Points with error bars represent the data and stacked histograms represent expected distributions. The 125 GeV Higgs boson signal and the ZZ backgrounds are normalized to the SM expectation, the Z+X background to the estimation from data. |
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Figure 5-b:
Distribution of $ {{\cal D}^{\rm kin}_{\rm bkg}} $ versus $ {m_{4\ell }}$ in the mass region 100 $ < {m_{4\ell }}< $ 170 GeV. The gray scale represents the expected relative density of ZZ background plus Higgs boson signal for $ {m_{ {\mathrm {H}} }}=$ 125 GeV. The points show the data and the horizontal bars represent the measured event-by-event mass uncertainties. Different marker styles are used to denote the categorization of the events. |
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Figure 6:
Distribution of categorization discriminants in the mass region 118 $ < {m_{4\ell }} < $ 130 GeV. Points with error bars represent the data and stacked histograms represent expected distributions. The 125 GeV Higgs boson signal and the ZZ backgrounds are normalized to the SM expectation, the Z+X background to the estimation from data. The vertical gray dashed lines denote the working points used in the event categorization. |
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Figure 6-a:
Distribution of categorization discriminant $ {{\cal D}_{\text{2jet}}} $ in the mass region 118 $ < {m_{4\ell }} < $ 130 GeV. Points with error bars represent the data and stacked histograms represent expected distributions. The 125 GeV Higgs boson signal and the ZZ backgrounds are normalized to the SM expectation, the Z+X background to the estimation from data. The vertical gray dashed line denotes the working points used in the event categorization. |
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Figure 6-b:
Distribution of categorization discriminant $ {{\cal D}_{\text{2jet}}} $ in the mass region 118 $ < {m_{4\ell }} < $ 130 GeV. Points with error bars represent the data and stacked histograms represent expected distributions. The 125 GeV Higgs boson signal and the ZZ backgrounds are normalized to the SM expectation, the Z+X background to the estimation from data. The vertical gray dashed line denotes the working points used in the event categorization. |
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Figure 6-c:
Distribution of categorization discriminant $ {{\cal D}_{\mathrm{WH}}} $ in the mass region 118 $ < {m_{4\ell }} < $ 130 GeV. Points with error bars represent the data and stacked histograms represent expected distributions. The 125 GeV Higgs boson signal and the ZZ backgrounds are normalized to the SM expectation, the Z+X background to the estimation from data. The vertical gray dashed line denotes the working points used in the event categorization. |
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Figure 6-d:
Distribution of categorization discriminant $ {{\cal D}_{\mathrm{ZH}}} $ in the mass region 118 $ < {m_{4\ell }} < $ 130 GeV. Points with error bars represent the data and stacked histograms represent expected distributions. The 125 GeV Higgs boson signal and the ZZ backgrounds are normalized to the SM expectation, the Z+X background to the estimation from data. The vertical gray dashed line denotes the working points used in the event categorization. |
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Figure 7:
Left: Significance of the local fluctuation with respect to the SM expectation as a function of the Higgs boson mass. Dashed lines show the mean expected significance of the SM Higgs boson for a given mass hypothesis. Right: Observed values of the signal strength $\mu =\sigma /\sigma _{SM}$ for the six event categories, compared to the combined $\mu $ shown as a vertical line. The horizontal bars and the filled band indicate the $\pm $1$\sigma $ uncertainties. The uncertainties include both statistical and systematic sources. |
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Figure 7-a:
Significance of the local fluctuation with respect to the SM expectation as a function of the Higgs boson mass. Dashed lines show the mean expected significance of the SM Higgs boson for a given mass hypothesis. |
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Figure 7-b:
Observed values of the signal strength $\mu =\sigma /\sigma _{SM}$ for the six event categories, compared to the combined $\mu $ shown as a vertical line. The horizontal bars and the filled band indicate the $\pm $1$\sigma $ uncertainties. The uncertainties include both statistical and systematic sources. |
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Figure 8:
Left: Result of the 2D likelihood scan for the $ {\mu _{ {\mathrm {g}} {\mathrm {g}} {\mathrm {H}} , {\mathrm {t}\overline {\mathrm {t}}} {\mathrm {H}} }} $ and $ {\mu _{\mathrm {VBF},\mathrm {V {\mathrm {H}} }}} $ signal-strength modifiers. The solid and dashed contours show the 68% and 95% CL regions, respectively. The cross indicates the best-fit values, and the diamond represents the expected values for the SM Higgs boson. Right: Results of likelihood scans for the signal strength modifiers corresponding to the five main Higgs boson production modes, compared to the combined $\mu $ shown as a vertical line. The horizontal bars and the filled band indicate the $\pm $1$\sigma $ uncertainties. The uncertainties include both statistical and systematic sources. |
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Figure 8-a:
Result of the 2D likelihood scan for the $ {\mu _{ {\mathrm {g}} {\mathrm {g}} {\mathrm {H}} , {\mathrm {t}\overline {\mathrm {t}}} {\mathrm {H}} }} $ and $ {\mu _{\mathrm {VBF},\mathrm {V {\mathrm {H}} }}} $ signal-strength modifiers. The solid and dashed contours show the 68% and 95% CL regions, respectively. The cross indicates the best-fit values, and the diamond represents the expected values for the SM Higgs boson. |
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Figure 8-b:
Results of likelihood scans for the signal strength modifiers corresponding to the five main Higgs boson production modes, compared to the combined $\mu $ shown as a vertical line. The horizontal bars and the filled band indicate the $\pm $1$\sigma $ uncertainties. The uncertainties include both statistical and systematic sources. |
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Figure 9:
Left: The measured fiducial cross section as a function of $\sqrt {s}$. The acceptance is calculated using POWHEG at $\sqrt {s}=$ 13 TeV and HRes [50,52] at $\sqrt {s} =$ 7 and 8 TeV and the theoretical uncertainty on the gluon fusion contribution is taken from Ref. [25]. The model dependence uses experimental constraints on the relative fraction of the various production modes, as described in the text, and is much less than 1% for the $\sqrt {s} =$ 7 and 8 TeV measurements. Right: measured fiducial cross section in each final state. The sub-dominant component of the the signal (VBF $+$ VH $+ { {\mathrm {t}}\bar{ \mathrm {t} } {\mathrm {H}} }$) is denoted as XH. |
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Figure 9-a:
The measured fiducial cross section as a function of $\sqrt {s}$. The acceptance is calculated using POWHEG at $\sqrt {s}=$ 13 TeV and HRes [50,52] at $\sqrt {s} =$ 7 and 8 TeV and the theoretical uncertainty on the gluon fusion contribution is taken from Ref. [25]. The model dependence uses experimental constraints on the relative fraction of the various production modes, as described in the text, and is much less than 1% for the $\sqrt {s} =$ 7 and 8 TeV measurements. |
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Figure 9-b:
Measured fiducial cross section in each final state. The sub-dominant component of the the signal (VBF $+$ VH $+ { {\mathrm {t}}\bar{ \mathrm {t} } {\mathrm {H}} }$) is denoted as XH. |
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Figure 10:
Result of the differential cross section measurement for $ {p_{\mathrm {T}}} ({\rm H})$ (left) and $N(\text{jets})$ (right). The acceptance and theoretical uncertainties in the differential bins are are calculated using POWHEG. |
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Figure 10-a:
Result of the differential cross section measurement for $ {p_{\mathrm {T}}} ({\rm H})$. The acceptance and theoretical uncertainties in the differential bins are are calculated using POWHEG. |
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Figure 10-b:
Result of the differential cross section measurement for $N(\text{jets})$. The acceptance and theoretical uncertainties in the differential bins are are calculated using POWHEG. |
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Figure 11:
left: 1D likelihood scan as a function of mass for the 1D, 2D, and 3D measurement. right: 1D likelihood scan as a function of mass for the different final states and the combination of all final states for the 3D measurement. Solid lines represents the scan with full uncertainties included, dashed lines statistical error only. |
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Figure 11-a:
1D likelihood scan as a function of mass for the 1D, 2D, and 3D measurement. Solid lines represents the scan with full uncertainties included, dashed lines statistical error only. |
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Figure 11-b:
1D likelihood scan as a function of mass for the different final states and the combination of all final states for the 3D measurement. Solid lines represents the scan with full uncertainties included, dashed lines statistical error only. |
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Figure 12:
Observed likelihood scan of $m_{\mathrm{H}}$ and $\Gamma _{\mathrm{H}}$ using the full mass range 100 $ < m_{4\ell } < $ 1600 GeV between 0 $ < \Gamma _{\mathrm{H}} < $ 100 MeV and the signal range 105 $ < m_{4\ell } < $ 140 GeV between 0 $ < \Gamma _{\mathrm{H}} < $ 5 GeV with 12.9 fb$^{-1}$ data. |
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Figure 12-a:
Observed likelihood scan of $m_{\mathrm{H}}$ and $\Gamma _{\mathrm{H}}$ using the full mass range 100 $ < m_{4\ell } < $ 1600 GeV between 0 $ < \Gamma _{\mathrm{H}} < $ 100 MeV with 12.9 fb$^{-1}$ data. |
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Figure 12-b:
Observed likelihood scan of $m_{\mathrm{H}}$ and $\Gamma _{\mathrm{H}}$ using the signal range 105 $ < m_{4\ell } < $ 140 GeV between 0 $ < \Gamma _{\mathrm{H}} < $ 5 GeV with 12.9 fb$^{-1}$ data. |
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Figure 13:
Observed and expected likelihood scan of $\Gamma _{\mathrm{H}}$ using the full mass range 100 $ < m_{4\ell } < $ 1600 GeV (left) or on-shell only range 105 $ < m_{4\ell } < $ 140 GeV (right) with 12.9 fb$^{-1}$ data, with $m_{\mathrm{H}}$ floated. |
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Figure 13-a:
Observed and expected likelihood scan of $\Gamma _{\mathrm{H}}$ using the full mass range 100 $ < m_{4\ell } < $ 1600 GeV with 12.9 fb$^{-1}$ data, with $m_{\mathrm{H}}$ floated. |
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Figure 13-b:
Observed and expected likelihood scan of $\Gamma _{\mathrm{H}}$ using the on-shell only range 105 $ < m_{4\ell } < $ 140 GeV with 12.9 fb$^{-1}$ data, with $m_{\mathrm{H}}$ floated. |
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Figure 14:
Distributions of events (data points) and expectations (histograms) in the following kinematic discriminants: $\mathcal {D}_\text {bkg}$ (top left), $\mathcal {D}_{0-}$ (top right), $\mathcal {D}_{CP}$ (middle left), $\mathcal {D}_\text {int}$ (middle right), $\mathcal {D}_{0h+}$ (bottom left), $\mathcal {D}_{\Lambda 1}$ (bottom right). |
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Figure 14-a:
Distributions of events (data points) and expectations (histograms) in the kinematic discriminant $\mathcal {D}_\text {bkg}$. |
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Figure 14-b:
Distributions of events (data points) and expectations (histograms) in the kinematic discriminant $\mathcal {D}_{0-}$. |
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Figure 14-c:
Distributions of events (data points) and expectations (histograms) in the kinematic discriminant $\mathcal {D}_{CP}$. |
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Figure 14-d:
Distributions of events (data points) and expectations (histograms) in the kinematic discriminant $\mathcal {D}_\text {int}$. |
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Figure 14-e:
Distributions of events (data points) and expectations (histograms) in the kinematic discriminant $\mathcal {D}_{0h+}$. |
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Figure 14-f:
Distributions of events (data points) and expectations (histograms) in the kinematic discriminant $\mathcal {D}_{\Lambda 1}$. |
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Figure 15:
Observed and expected likelihood scan of the $f_{a3}\cos(\phi _{a3})$ (top), $f_{a2}\cos(\phi _{a2})$ (middle), $f_{\Lambda 1}\cos(\phi _{\Lambda 1})$ (bottom) parameters with 15.7 fb$^{-1}$ of data at 13 TeV. It is assumed that ratios of anomalous couplings are real and therefore $\cos(\phi _{ai})= \pm$1. |
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Figure 15-a:
Observed and expected likelihood scan of the $f_{a3}\cos(\phi _{a3})$ parameter with 15.7 fb$^{-1}$ of data at 13 TeV. It is assumed that ratios of anomalous couplings are real and therefore $\cos(\phi _{ai})= \pm$1. |
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Figure 15-b:
Observed and expected likelihood scan of the $f_{a2}\cos(\phi _{a2})$ parameter with 15.7 fb$^{-1}$ of data at 13 TeV. It is assumed that ratios of anomalous couplings are real and therefore $\cos(\phi _{ai})= \pm$1. |
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Figure 15-c:
Observed and expected likelihood scan of the $f_{\Lambda 1}\cos(\phi _{\Lambda 1})$ parameter with 15.7 fb$^{-1}$ of data at 13 TeV. It is assumed that ratios of anomalous couplings are real and therefore $\cos(\phi _{ai})= \pm$1. |
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Figure 16:
Top: Observed and expected upper limits at the 95% CL on the $\mathrm{X}\to ZZ \to 4\ell $ cross section $\sigma _\mathrm{X}$ (including four-lepton branching fraction) as a function of $m_\mathrm{X}$ at several $\Gamma _\mathrm{X}$ values with $f_{\rm VBF}$ floated, with 12.9 fb$^{-1}$ of data at 13 TeV. Bottom: Same as above but with $f_{\rm VBF}=1$ fixed. |
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Figure 16-a:
Observed and expected upper limits at the 95% CL on the $\mathrm{X}\to ZZ \to 4\ell $ cross section $\sigma _\mathrm{X}$ (including four-lepton branching fraction) as a function of $m_\mathrm{X}$ at several $\Gamma _\mathrm{X}$ values with $f_{\rm VBF}$ floated, with 12.9 fb$^{-1}$ of data at 13 TeV. |
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Figure 16-b:
Observed and expected upper limits at the 95% CL on the $\mathrm{X}\to ZZ \to 4\ell $ cross section $\sigma _\mathrm{X}$ (including four-lepton branching fraction) as a function of $m_\mathrm{X}$ at several $\Gamma _\mathrm{X}$ values with $f_{\rm VBF}=1$ fixed, with 12.9 fb$^{-1}$ of data at 13 TeV. |
| Tables | |
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Table 1:
List of observables $\vec{x}$ used in the analysis of the HVV anomalous couplings. The $\mathcal {D}_{0h+}$ discriminant is included in the $f_{\Lambda 1}$ measurement in order to allow a joint fit with $f_{a2}$. For more details, see Ref. [15]. |
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Table 2:
The number of observed candidate events compared to the mean expected background and signal rates for each final state, for the full mass range $ {m_{4\ell }}>$ 70 GeV. Uncertainties include statistical and systematic sources. |
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Table 3:
The number of observed candidate events compared to the mean expected background and signal rates for each final state, for the mass range 118 $< {m_{4\ell }}<$ 130 GeV. Uncertainties include statistical and systematic sources. |
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Table 4:
The number of observed candidate events compared to the mean expected background and signal rates for each event category, for the mass range 118 $ < {m_{4\ell }}<$ 130 GeV. |
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Table 5:
Summary of the systematic uncertainties in the $ { {\mathrm {H}} \to 4\ell }$ measurements. |
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Table 6:
Summary of requirements and selections used in the definition of the fiducial phase space for the $ { {\mathrm {H}} \to 4\ell }$ cross section measurements. |
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Table 7:
Summary of different Standard Model signal models. For all production modes the values given are for $m_{\rm H}=$ 125 GeV. The uncertainties listed are statistical uncertainties only, and the statistical uncertainty on the acceptance is $\sim$0.001. |
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Table 8:
Best fit values for the mass of the new boson measured in the $4\ell $, $\ell = {\mathrm {e}}, {{\mu }}$ final states, with 1D, 2D and 3D fit, respectively, as described in the text along with the uncertainty. For the 1D and 2D we give the total uncertainty only, while for the nominal 3D fit we separate the contribution from statistical and systematic uncertainty. |
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Table 9:
Summary of allowed 68%CL (central values with uncertainties) and 95%CL (ranges in square brackets) intervals on the width $\Gamma _{\mathrm{H}}$ of the ${\rm H}(125)$ boson. The expected results are quoted for the SM signal production cross section ($\mu _{\rm VBF+VH}=\mu _{\rm ggH+mathrm{ t \bar{t} }H}=1$) and the values of $m_{\mathrm{H}}=$ 125 GeV and $\Gamma _{\mathrm{H}}=$ 0.0041 GeV. |
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Table 10:
Summary of allowed 68%CL (central values with uncertainties) and 95%CL (ranges in square brackets) intervals on anomalous coupling parameters in HZZ interactions under the assumption that all the coupling ratios are real ($\phi _{ai}=$ 0 or $\pi $). The $f_{\Lambda 1}\cos(\phi _{\Lambda 1})$ observed 68%CL interval allows values below $-1$ in order to include the range $ [0.91,1.00]$. The expected results are quoted for the SM signal production cross section ($\mu =$ 1). |
| Summary |
| Several studies of Higgs boson production in the four-lepton final state at $ \sqrt{s} = $ 13 TeV have been presented, using data samples corresponding to an integrated luminosity of 12.9 fb$^{-1}$. The observed significance for the SM Higgs boson at a mass of $m_{\mathrm{ H }}=$ 125.09 GeV is 6.2$\sigma$, where the expected significance is 6.5$\sigma$. The measured signal strength is $\mu =$ 0.99$^{+0.33}_{-0.26} $, and the measured signal strength modifiers associated with fermions and vector bosons are ${\mu_{\mathrm{gg}\mathrm{ H },\,\mathrm{ t \bar{t} }\mathrm{ H }}} =$ 1.00$^{+0.39}_{-0.32}$ and ${\mu_{\mathrm{VBF},\mathrm{V\mathrm{ H }}}} =$ 0.91$^{+1.56}_{-0.91}$, respectively. The model-independent fiducial cross section at $ \sqrt{s} = $ 13 TeV for this boson is measured to be 2.29$^{+0.74}_{-0.64}$ (stat)$^{+0.30}_{-0.23}$ (syst)$^{+0.01}_{-0.05}$ (model dep.) fb. The mass is measured to be $m_{{\rm H}}=$ 124.50$^{+0.48}_{-0.46} $ GeV and the width is constrained to be $\Gamma_{{\rm H}}<$ 41 MeV. Constraints on spin-zero anomalous couplings are set. All results are consistent, within their uncertainties, with the expectations for the SM Higgs boson. In addition, upper limits at a 95% CL are set on the production of an additional Higgs boson for masses up to 2.5 TeV and for various widths. The details of the exclusions depend on the assumptions of width and production, but in general no significant excesses appear under any of the scenarios considered. |
| Additional Figures | |
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Additional Figure 1:
Distribution of the $\mathrm{ Z } _1$ (left) and $\mathrm{ Z } _2$ (middle) reconstructed invariant masses in the region $m_{4\ell } > $ 70 GeV. The stacked histograms represent expected distributions, and points represent the data. The 125 GeV Higgs boson signal and the ZZ backgrounds are normalized to the SM expectation and the Z+X background to the estimation from data. Right: Correlation between the reconstructed invariant masses $\mathrm{ Z } _1$ and $\mathrm{ Z } _2$ in the region $m_{4\ell }> $ 70 GeV. The gray scale represents the expected relative density of ZZ background plus Higgs boson signal for $m_{\rm H}=$ 125 GeV. |
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Additional Figure 1-a:
Distribution of the $\mathrm{ Z } _1$ reconstructed invariant mass in the region $m_{4\ell } > $ 70 GeV. The stacked histograms represent expected distributions, and points represent the data. The 125 GeV Higgs boson signal and the ZZ backgrounds are normalized to the SM expectation and the Z+X background to the estimation from data. |
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Additional Figure 1-b:
Distribution of the $\mathrm{ Z } _2$ reconstructed invariant mass in the region $m_{4\ell } > $ 70 GeV. The stacked histograms represent expected distributions, and points represent the data. The 125 GeV Higgs boson signal and the ZZ backgrounds are normalized to the SM expectation and the Z+X background to the estimation from data. |
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Additional Figure 1-c:
Correlation between the reconstructed invariant masses $\mathrm{ Z } _1$ and $\mathrm{ Z } _2$ in the region $m_{4\ell }> $ 70 GeV. The gray scale represents the expected relative density of ZZ background plus Higgs boson signal for $m_{\rm H}=$ 125 GeV. |
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Additional Figure 2:
Left: Distribution of ${\cal D}^{\rm kin}_{\rm bkg}$ in the region $m_{4\ell }> $ 70 GeV. The stacked histograms represent the expected distributions, and points represent the data. The 125 GeV Higgs boson signal and the ZZ backgrounds are normalized to the SM expectation and the Z+X background to the estimation from data. Right: 2D distribution of ${\cal D}^{\rm kin}_{\rm bkg}$ vs $m_{4\ell }$ in the region 170 $ < m_{4\ell } < $ 850 GeV. The gray scale represents the expected relative density of ZZ background plus Higgs boson signal for $m_{\rm H}=$ 125 GeV. The points show the data and the horizontal bars represent the measured event-by-event mass uncertainties. |
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Additional Figure 2-a:
Distribution of ${\cal D}^{\rm kin}_{\rm bkg}$ in the region $m_{4\ell }> $ 70 GeV. The stacked histograms represent the expected distributions, and points represent the data. The 125 GeV Higgs boson signal and the ZZ backgrounds are normalized to the SM expectation and the Z+X background to the estimation from data. |
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Additional Figure 2-b:
2D distribution of ${\cal D}^{\rm kin}_{\rm bkg}$ vs $m_{4\ell }$ in the region 170 $ < m_{4\ell } < $ 850 GeV. The gray scale represents the expected relative density of ZZ background plus Higgs boson signal for $m_{\rm H}=$ 125 GeV. The points show the data and the horizontal bars represent the measured event-by-event mass uncertainties. |
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Additional Figure 3:
2D distributions of ${\mathcal D}_{\rm 1jet}$ (top left), ${\mathcal D}_{\rm 2jet}$ (top right), ${\mathcal D}_{\rm WH}$ (bottom left) and ${\mathcal D}_{\rm ZH}$ (bottom right) vs $m_{4\ell }$ in the region 100 $ < m_{4\ell } < $ 170 GeV. The gray scale represents the expected relative density of ZZ background plus Higgs boson signal for $m_{\rm H}=$ 125 GeV. The points show the data and the horizontal bars represent the measured event-by-event mass uncertainties. The gray dashed lines denote the working points used in the event categorization and different marker styles are used to denote the final categorization of the events. |
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Additional Figure 3-a:
2D distribution of ${\mathcal D}_{\rm 1jet}$ vs $m_{4\ell }$ in the region 100 $ < m_{4\ell } < $ 170 GeV. The gray scale represents the expected relative density of ZZ background plus Higgs boson signal for $m_{\rm H}=$ 125 GeV. The points show the data and the horizontal bars represent the measured event-by-event mass uncertainties. The gray dashed lines denote the working points used in the event categorization and different marker styles are used to denote the final categorization of the events. |
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Additional Figure 3-b:
2D distribution of ${\mathcal D}_{\rm 2jet}$ vs $m_{4\ell }$ in the region 100 $ < m_{4\ell } < $ 170 GeV. The gray scale represents the expected relative density of ZZ background plus Higgs boson signal for $m_{\rm H}=$ 125 GeV. The points show the data and the horizontal bars represent the measured event-by-event mass uncertainties. The gray dashed lines denote the working points used in the event categorization and different marker styles are used to denote the final categorization of the events. |
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Additional Figure 3-c:
2D distribution of ${\mathcal D}_{\rm WH}$ vs $m_{4\ell }$ in the region 100 $ < m_{4\ell } < $ 170 GeV. The gray scale represents the expected relative density of ZZ background plus Higgs boson signal for $m_{\rm H}=$ 125 GeV. The points show the data and the horizontal bars represent the measured event-by-event mass uncertainties. The gray dashed lines denote the working points used in the event categorization and different marker styles are used to denote the final categorization of the events. |
png pdf |
Additional Figure 3-d:
2D distribution of ${\mathcal D}_{\rm ZH}$ vs $m_{4\ell }$ in the region 100 $ < m_{4\ell } < $ 170 GeV. The gray scale represents the expected relative density of ZZ background plus Higgs boson signal for $m_{\rm H}=$ 125 GeV. The points show the data and the horizontal bars represent the measured event-by-event mass uncertainties. The gray dashed lines denote the working points used in the event categorization and different marker styles are used to denote the final categorization of the events. |
png pdf |
Additional Figure 4:
Significance of the local fluctuation with respect to the SM expectation as a function of the Higgs boson mass using the 1D (gray) and 2D (black) likelihood. Dashed lines show the mean expected significance of the SM Higgs boson for a given mass hypothesis and solid lines show the observed significance. |
png pdf |
Additional Figure 5:
Comparison of measured mass resolution with the predicted dilepton mass resolution using the event-by-event mass uncertainty for $\mathrm{ Z } \to \ell \ell $ events in data. The dashed lines denote a $\pm$20% region, used as the systematic uncertainty on the resolution. |
png pdf |
Additional Figure 6:
Distribution of $m_{4\ell }$ for events in the reduced selection electron category used in the search for a high mass resonance. The ZZ backgrounds are normalized to the SM expectation and the Z+X background to the estimation from data. |
| Additional Material |
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Higgs and associated vector boson event recorded by CMS (Run 2, 13 TeV)
The following figures display a real proton-proton collision event at 13 TeV in the CMS detector in which two high-energy electrons (green lines), two high-energy muons (red lines), and two high-energy jets (dark yellow cones) are observed. The event shows characteristics expected in the production of a Higgs boson in association with a vector boson with the decay of the Higgs boson in four leptons and the decay of the vector boson in two jets, and is also consistent with background standard model physics processes. Photograph: Mc Cauley, Thomas Link to CDS record: CMS-PHO-EVENTS-2016-006. |
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Higgs boson produced via vector boson fusion event recorded by CMS (Run 2, 13 TeV)
The following figures display a real proton-proton collision event at 13 TeV in the CMS detector in which two high-energy electrons (green lines), two high-energy muons (red lines), and two-high energy jets (dark yellow cones) are observed. The event shows characteristics expected from Higgs boson production via vector boson fusion with subsequent decay of the Higgs boson in four leptons, and is also consistent with background standard model physics processes. Photograph: Mc Cauley, Thomas Link to CDS record: CMS-PHO-EVENTS-2016-007. |
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