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Search for resonant and nonresonant new phenomena in high-mass dilepton final states at $\sqrt{s} =$ 13 TeV

The collaboration
CMS-EXO-19-019, 2021.

Abstract (data abstract)
A search for physics beyond the standard model (SM) is presented using electron or muon pairs with high invariant mass. A data set of proton-proton collisions collected by the CMS experiment at the LHC at $\sqrt{s}=13$ TeV recorded in years 2016 to 2018 and corresponding to a total integrated luminosity of up to 140 $\mathrm{fb}^{-1}$ is analyzed. No significant deviation is observed with respect to the expectation from the SM backgrounds. Upper limits are set on the ratio of the product of production cross section and branching fraction in a dilepton channel of a new narrow resonance to that of the Z boson and converted into lower limits on the masses of various hypothetical particles. A spin-1 $\mathrm{Z}^{\prime}_{\mathrm{SSM}}$ ($\mathrm{Z}^{\prime}_{\psi}$) particle, arising in the sequential SM (superstring-inspired model) is excluded below a mass of 5.15 (4.56) TeV at 95% confidence level. Lower limits of 2.47--4.78 TeV on the mass of spin-2 gravitons in the Randall-Sundrum are set for values of the dimensionless coupling parameter $k/\overline{M}_{\mathrm{Pl}}$ between 0.01 and 0.1. Limits on the mass of a spin-1 mediator between the SM and dark matter particles ranging from 1.04 to 4.64 TeV are set in multiple signal models. In case of a four-fermion contact interaction, lower limits on the ultraviolet cutoff parameter $\Lambda$ ranging from 23.6 to 36.6,\TeV are set. In the Arkani-Hamed, Dimopoulos, and Dvali model with large extra dimensions, lower limits on $\Lambda$ ranging from 6.0 to 8.9 TeV are set, depending on the parameter convention. For the first time in the same-flavor final state, lepton flavor universality is tested at high mass comparing the dimuon and dielectron mass spectra, corrected for detector effects. No significant deviation from the SM expectation of unity is observed.

• #### Acceptance x Efficiency as a function of dielectron mass

Data from Figure 1 (left).

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Product of acceptance and efficiency for dielectron pairs as a function of generated mass in simulated events. The DY samples...

• #### Acceptance x Efficiency as a function of dimuon mass

Data from Figure 1 (right).

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Product of acceptance and efficiency for dimuon pairs as a function of generated mass in simulated events. The DY samples...

• #### Dielectron mass distribution

Data from Figure 2, left panel.

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The invariant mass spectra of dielectron events. The points with error bars represent the observed yield. The histogram represents the...

• #### Dimuon mass distribution

Data from Figure 2, right panel.

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The invariant mass spectra of dimuon events. The points with error bars represent the observed yield. The histogram represents the...

• #### Dielectron mass distribution for negative $\cos\theta^*$

Data from Figure 3, upper left panel.

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• #### Dimuon mass distribution for negative $\cos \theta^*$

Data from Figure 3, lower left panel.

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• #### Data and estimated background yields in the dielectron channel

Data from Table 4 (upper half).

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Observed and expected background yields for different mass ranges in the dielectron channel. The sum of all background contributions is...

• #### Data and estimated background yields in the dimuon channel

Data from Table 4 (lower half).

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Observed and expected background yields for different mass ranges in the dimuon channel. The sum of all background contributions is...

• #### Observed limit in narrow width, spin 1

Data from all panels of Figure 4.

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The observed upper limits at 95% CL on the product of production cross section and branching fraction for a spin-1...

• #### Expected limits in narrow width, spin 1

Data from all panels of Figure 4.

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The expected upper limits together with the 68 and 95% quantiles at 95% CL on the product of production cross...

• #### Observed limits for different widths, spin 1

Data from all panels of Figure 5.

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The observed upper limits at 95% CL on the product of production cross section and branching fraction for a spin-1...

• #### Expected limits for different widths, spin 1

Data from all panels of Figure 5.

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The expected upper limits at 95% CL on the product of production cross section and branching fraction for a spin-1...

• #### Curve for GSM models in the $c_{u}$-$c_{d}$ scan in Figure 6

Data from Figure 6.

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Limits in the ( $c_{d}$ , $c_{u}$ ) plane obtained by recasting the combined limit at 95% CL on the...

• #### Curve for LR models in the $c_{u}$-$c_{d}$ scan in Figure 6

Data from Figure 6.

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Limits in the ( $c_{d}$ , $c_{u}$ ) plane obtained by recasting the combined limit at 95% CL on the...

• #### Curve for E6 models in the $c_{u}$-$c_{d}$ scan in Figure 6

Data from Figure 6.

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Limits in the ( $c_{d}$ , $c_{u}$ ) plane obtained by recasting the combined limit at 95% CL on the...

• #### Local p-Values for different widths in the dielectron channel

Data from Figure 7, top left panel.

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The observed local p-value for the dielectron channel as a function of the dilepton invariant mass.

• #### Local p-Values for different widths in the dimuon channel

Data from Figure 7, top left panel.

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The observed local p-value for the dimuon channel as a function of the dilepton invariant mass.

• #### Local p-Values for different widths in the combined channel

Data from Figure 7, top left panel.

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The observed local p-value for the combined channel as a function of the dilepton invariant mass.

• #### Observed limit in narrow width, spin 2

Data from all panels of Figure 8.

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The observed upper limits at 95% CL on the product of production cross section and branching fraction for a spin-2...

• #### Expected limits in narrow width, spin 2

Data from all panels of Figure 8.

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The expected upper limits together with the 68 and 95% quantiles at 95% CL on the product of production cross...

• #### DM exclusion contour (Vector, Expected)

Data from Figure 9 (left).

10.17182/hepdata.101186.v1/t23

Limits at 95% confidence level for the masses of the DM particle, which is assumed to be Dirac fermion, and...

• #### First DM exclusion contour (Vector, Observed)

Data from Figure 9 (left).

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Limits at 95% confidence level for the masses of the DM particle, which is assumed to be Dirac fermion, and...

• #### DM exclusion contour (Axial, Expected)

Data from Figure 9 (right).

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Limits at 95% confidence level for the masses of the DM particle, which is assumed to be Dirac fermion, and...

• #### DM exclusion contour (Axial, Observed)

Data from Figure 9 (right).

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Limits at 95% confidence level for the masses of the DM particle, which is assumed to be Dirac fermion, and...

• #### Limits on the UV cutoff in the ADD model in the electron channel

Data from the upper left panel of Figure 10.

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Exclusion limits at 95% CL on the ultraviolet cutoff for the dielectron channel, with $m_{\ell\ell}>1.8$ TeV ($m_{\ell\ell}>1.9$ TeV for 2016)...

• #### Limits on the UV cutoff in the ADD model in the dimuon channel

Data from the lower panel of Figure 10.

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Exclusion limits at 95% CL on the ultraviolet cutoff for the dimuon channel, with $m_{\ell\ell}>1.8$ TeV ($m_{\ell\ell}>1.9$ TeV for 2016)...

• #### Limits on the UV cutoff in the ADD model in the combined channel

Data from the lower panel of Figure 10.

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Exclusion limits at 95% CL on the ultraviolet cutoff for the combination of the dielectron and dimuon channel, with $m_{\ell\ell}>1.8$...

• #### Limits on the CI scale Lambda in the dielectron channel

Data from the upper left panel of Figure 11.

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Dilepton lower exclusion limits at 95% CL on the CI scale ($\Lambda$) for the eight CI models considered, for the...

• #### Limits on the CI scale Lambda in the dimuon channel

Data from the upper right panel of Figure 11.

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Dilepton lower exclusion limits at 95% CL on the CI scale ($\Lambda$) for the eight CI models considered, for the...

• #### Limits on the CI scale Lambda for the combined channels

Data from the lower panel of Figure 11.

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Dilepton lower exclusion limits at 95% CL on the CI scale ($\Lambda$) for the eight CI models considered, for the...

• #### Flavor ratio as a function of mass for central leptons.

Data from Figure 12 (left).

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Ratio of the differential dilepton production cross section in the dimuon and dielectron channels $R_{\mu^{+}\mu^{-}/e^{+}e^{-}}$, as a function of $m_{\ell\ell}$...

• #### Flavor ratio as a function of mass for forward leptons.

Data from Figure 12 (right).

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Ratio of the differential dilepton production cross section in the dimuon and dielectron channels $R_{\mu^{+}\mu^{-}/e^{+}e^{-}}$, as a function of $m_{\ell\ell}$...

• #### Dielectron mass resolution as a function of dielectron mass

Data from supplemenatary Figure 1.

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Invariant mass resolution for dielectron pairs as obtained from simulated DY samples as a function of generated mass.

• #### Dimuon mass resolution as a function of dimuon mass

Data from supplemenatary Figure 2.

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Invariant mass resolution for dimuon pairs as obtained from simulated DY samples as a function of generated mass.

• #### Data and background estimate for the CI limit calculation.

Supplementary material.

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Observed data and total background estimate in all bins used in the limit calculation for the CI limits. The total...

• #### Data and background estimate for the ADD limit calculation.

Supplementary material.

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Observed data and total background estimate in all bins used in the limit calculation for the ADD limits. The total...

• #### Bin-by-bin correlation for the CI limit calculation.

Supplementary material.

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Bin-by-bin correlation for the limit calculation for the CI limits. The bin names indicate the $\cos\theta^*$ bin (cspos for positive...

• #### Bin-by-bin correlation for the ADD limit calculation.

Supplementary material.

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Bin-by-bin correlation for the limit calculation for the ADD limits. The bin names indicate the $\cos\theta^*$ bin (cspos for positive...