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The distribution of events passing the selection requirements in the electron-pair channel as a function of dilepton invariant mass \Mll\ (left) and electron pseudorapidity $\eta$ (right). Events are shown for the \Mll\ range $46 \GeV$ to $150 \GeV$. The MC signal sample (yellow) is simulated using \Powheg{}+\Pythia{}. The statistical uncertainties on the data points are smaller than the size of the markers and the systematic uncertainties are not plotted. The prediction is normalised to the integral of the data. The vertical dashed lines on the left-hand plot at \Mll{} values of $66 \GeV$ and $116 \GeV$ indicate the boundaries between the three principal \Mll{} regions employed in the analysis. The small discontinuities in the \Mll{} distribution at $66 \GeV$ and $116 \GeV$ are due to the absence of the isolation requirement around the \Zboson{}-boson mass peak.

The distribution of events passing the selection requirements in the electron-pair channel as a function of dilepton invariant mass \Mll\ (left) and electron pseudorapidity $\eta$ (right). Events are shown for the \Mll\ range $46 \GeV$ to $150 \GeV$. The MC signal sample (yellow) is simulated using \Powheg{}+\Pythia{}. The statistical uncertainties on the data points are smaller than the size of the markers and the systematic uncertainties are not plotted. The prediction is normalised to the integral of the data. The vertical dashed lines on the left-hand plot at \Mll{} values of $66 \GeV$ and $116 \GeV$ indicate the boundaries between the three principal \Mll{} regions employed in the analysis. The small discontinuities in the \Mll{} distribution at $66 \GeV$ and $116 \GeV$ are due to the absence of the isolation requirement around the \Zboson{}-boson mass peak.

The distribution of events passing the selection requirements in the muon-pair channel as a function of dilepton invariant mass \Mll\ (left) and muon pseudorapidity $\eta$ (right). Events are shown for the \Mll\ range $46 \GeV$ to $150 \GeV$. The MC signal sample (yellow) is simulated using \Powheg{}+\Pythia{}. The statistical uncertainties on the data points are smaller than the size of the markers and the systematic uncertainties are not plotted. The prediction is normalised to the integral of the data. The vertical dashed lines on the left hand plot at \Mll{} values of $66 \GeV$ and $116 \GeV$ indicate the boundaries between the three principal \Mll{} regions employed in the analysis.

The distribution of events passing the selection requirements in the muon-pair channel as a function of dilepton invariant mass \Mll\ (left) and muon pseudorapidity $\eta$ (right). Events are shown for the \Mll\ range $46 \GeV$ to $150 \GeV$. The MC signal sample (yellow) is simulated using \Powheg{}+\Pythia{}. The statistical uncertainties on the data points are smaller than the size of the markers and the systematic uncertainties are not plotted. The prediction is normalised to the integral of the data. The vertical dashed lines on the left hand plot at \Mll{} values of $66 \GeV$ and $116 \GeV$ indicate the boundaries between the three principal \Mll{} regions employed in the analysis.

Left: the distribution of the smallest of the isolation variables of the two electrons \Iemin{}. Right: the distribution of the muon isolation variable \Imu. The data for $66 \GeV < \Mll < 116 \GeV$ are compared to the sum of the estimated multi-jet background and all other processes, which are estimated from MC simulation. The red dashed lines indicate the range over which the fit is performed.

Left: the distribution of the smallest of the isolation variables of the two electrons \Iemin{}. Right: the distribution of the muon isolation variable \Imu. The data for $66 \GeV < \Mll < 116 \GeV$ are compared to the sum of the estimated multi-jet background and all other processes, which are estimated from MC simulation. The red dashed lines indicate the range over which the fit is performed.

Uncertainty from various sources on $(1/\sigma)\, \mathrm{d}\sigma / \mathrm{d}\phistar$ (top) and $(1/\sigma)\, \mathrm{d}\sigma / \mathrm{d}\Zpt$ (bottom) for events with $66 \GeV < \Mll < 116 \GeV$ and $\mody<2.4$. Left: electron-pair channel at dressed level. Right: muon-pair channel at bare level.

Uncertainty from various sources on $(1/\sigma)\, \mathrm{d}\sigma / \mathrm{d}\phistar$ (top) and $(1/\sigma)\, \mathrm{d}\sigma / \mathrm{d}\Zpt$ (bottom) for events with $66 \GeV < \Mll < 116 \GeV$ and $\mody<2.4$. Left: electron-pair channel at dressed level. Right: muon-pair channel at bare level.

Uncertainty from various sources on $(1/\sigma)\, \mathrm{d}\sigma / \mathrm{d}\phistar$ (top) and $(1/\sigma)\, \mathrm{d}\sigma / \mathrm{d}\Zpt$ (bottom) for events with $66 \GeV < \Mll < 116 \GeV$ and $\mody<2.4$. Left: electron-pair channel at dressed level. Right: muon-pair channel at bare level.

Uncertainty from various sources on $(1/\sigma)\, \mathrm{d}\sigma / \mathrm{d}\phistar$ (top) and $(1/\sigma)\, \mathrm{d}\sigma / \mathrm{d}\Zpt$ (bottom) for events with $66 \GeV < \Mll < 116 \GeV$ and $\mody<2.4$. Left: electron-pair channel at dressed level. Right: muon-pair channel at bare level.

The Born-level distributions of $(1/\sigma)\, \mathrm{d}\sigma / \mathrm{d}\phistar$ for the combination of the electron-pair and muon-pair channels, shown in three \Mll\ regions from $46 \GeV$ to $150 \GeV$ for $\mody<2.4$. The central panel of each plot shows the ratios of the values from the individual channels to the combined values, where the error bars on the individual-channel measurements represent the total uncertainty uncorrelated between bins. The light-green band represents the data statistical uncertainty on the combined value and the dark-green band represents the total uncertainty (statistical and systematic). The $\chi^2$ per degree of freedom is given. The lower panel of each plot shows the pull, defined as the difference between the electron-pair and muon-pair values divided by the uncertainty on that difference.

The Born-level distributions of $(1/\sigma)\, \mathrm{d}\sigma / \mathrm{d}\phistar$ for the combination of the electron-pair and muon-pair channels, shown in three \Mll\ regions from $46 \GeV$ to $150 \GeV$ for $\mody<2.4$. The central panel of each plot shows the ratios of the values from the individual channels to the combined values, where the error bars on the individual-channel measurements represent the total uncertainty uncorrelated between bins. The light-green band represents the data statistical uncertainty on the combined value and the dark-green band represents the total uncertainty (statistical and systematic). The $\chi^2$ per degree of freedom is given. The lower panel of each plot shows the pull, defined as the difference between the electron-pair and muon-pair values divided by the uncertainty on that difference.

The Born-level distributions of $(1/\sigma)\, \mathrm{d}\sigma / \mathrm{d}\phistar$ for the combination of the electron-pair and muon-pair channels, shown in three \Mll\ regions from $46 \GeV$ to $150 \GeV$ for $\mody<2.4$. The central panel of each plot shows the ratios of the values from the individual channels to the combined values, where the error bars on the individual-channel measurements represent the total uncertainty uncorrelated between bins. The light-green band represents the data statistical uncertainty on the combined value and the dark-green band represents the total uncertainty (statistical and systematic). The $\chi^2$ per degree of freedom is given. The lower panel of each plot shows the pull, defined as the difference between the electron-pair and muon-pair values divided by the uncertainty on that difference.

The Born-level distributions of $(1/\sigma)\, \mathrm{d}\sigma / \mathrm{d}\Zpt$ for the combination of the electron-pair and muon-pair channels, shown in six \Mll\ regions for $\mody<2.4$. The central panel of each plot shows the ratios of the values from the individual channels to the combined values, where the error bars on the individual-channel measurements represent the total uncertainty uncorrelated between bins. The light-blue band represents the data statistical uncertainty on the combined value and the dark-blue band represents the total uncertainty (statistical and systematic). The $\chi^2$ per degree of freedom is given. The lower panel of each plot shows the pull, defined as the difference between the electron-pair and muon-pair values divided by the uncertainty on that difference.

The Born-level distributions of $(1/\sigma)\, \mathrm{d}\sigma / \mathrm{d}\Zpt$ for the combination of the electron-pair and muon-pair channels, shown in six \Mll\ regions for $\mody<2.4$. The central panel of each plot shows the ratios of the values from the individual channels to the combined values, where the error bars on the individual-channel measurements represent the total uncertainty uncorrelated between bins. The light-blue band represents the data statistical uncertainty on the combined value and the dark-blue band represents the total uncertainty (statistical and systematic). The $\chi^2$ per degree of freedom is given. The lower panel of each plot shows the pull, defined as the difference between the electron-pair and muon-pair values divided by the uncertainty on that difference.

The Born-level distributions of $(1/\sigma)\, \mathrm{d}\sigma / \mathrm{d}\Zpt$ for the combination of the electron-pair and muon-pair channels, shown in six \Mll\ regions for $\mody<2.4$. The central panel of each plot shows the ratios of the values from the individual channels to the combined values, where the error bars on the individual-channel measurements represent the total uncertainty uncorrelated between bins. The light-blue band represents the data statistical uncertainty on the combined value and the dark-blue band represents the total uncertainty (statistical and systematic). The $\chi^2$ per degree of freedom is given. The lower panel of each plot shows the pull, defined as the difference between the electron-pair and muon-pair values divided by the uncertainty on that difference.

The Born-level distributions of $(1/\sigma)\, \mathrm{d}\sigma / \mathrm{d}\Zpt$ for the combination of the electron-pair and muon-pair channels, shown in six \Mll\ regions for $\mody<2.4$. The central panel of each plot shows the ratios of the values from the individual channels to the combined values, where the error bars on the individual-channel measurements represent the total uncertainty uncorrelated between bins. The light-blue band represents the data statistical uncertainty on the combined value and the dark-blue band represents the total uncertainty (statistical and systematic). The $\chi^2$ per degree of freedom is given. The lower panel of each plot shows the pull, defined as the difference between the electron-pair and muon-pair values divided by the uncertainty on that difference.

The Born-level distributions of $(1/\sigma)\, \mathrm{d}\sigma / \mathrm{d}\Zpt$ for the combination of the electron-pair and muon-pair channels, shown in six \Mll\ regions for $\mody<2.4$. The central panel of each plot shows the ratios of the values from the individual channels to the combined values, where the error bars on the individual-channel measurements represent the total uncertainty uncorrelated between bins. The light-blue band represents the data statistical uncertainty on the combined value and the dark-blue band represents the total uncertainty (statistical and systematic). The $\chi^2$ per degree of freedom is given. The lower panel of each plot shows the pull, defined as the difference between the electron-pair and muon-pair values divided by the uncertainty on that difference.

The Born-level distributions of $(1/\sigma)\, \mathrm{d}\sigma / \mathrm{d}\Zpt$ for the combination of the electron-pair and muon-pair channels, shown in six \Mll\ regions for $\mody<2.4$. The central panel of each plot shows the ratios of the values from the individual channels to the combined values, where the error bars on the individual-channel measurements represent the total uncertainty uncorrelated between bins. The light-blue band represents the data statistical uncertainty on the combined value and the dark-blue band represents the total uncertainty (statistical and systematic). The $\chi^2$ per degree of freedom is given. The lower panel of each plot shows the pull, defined as the difference between the electron-pair and muon-pair values divided by the uncertainty on that difference.

Born-level fiducial cross sections in bins of \Mll\ for the combination of the electron-pair and muon-pair channels. The middle plot shows the ratios of the values from the individual channels to the combined values, where the error bars on the individual-channel measurements represent the total uncertainty uncorrelated between bins. The light-blue band represents the data statistical uncertainty on the combined value. The dark-blue band represents the total uncertainty (statistical and systematic), except for the uncertainty of 2.8\% on the integrated luminosity, which is fully correlated between channels and among all \Mll\ bins. The $\chi^2$ per degree of freedom is given. The lower plot shows the pull, defined as the difference between the electron-pair and muon-pair values divided by the uncertainty on that difference. The fiducial regions to which these cross sections correspond are specified in Table~\protect\ref{tab:FiducialDefinition}. Note that \Zpt{} is required to be greater than $45 \GeV$ for $\Mll{}<46 \GeV$.

The ratio of the predictions of \Resbos\ for the $Z$-boson mass peak and for \mody~$<$~2.4 to the combined Born-level data for $(1/\sigma)\,\mathrm{d}\sigma / \mathrm{d}\phistar$ (top) and $(1/\sigma)\,\mathrm{d}\sigma / \mathrm{d}\Zpt$ (bottom). The light-green (light-blue) band represents the statistical uncertainty on the data for \phistar\ (\Zpt) and the dark-green (dark-blue) band represents the total uncertainty (statistical and systematic) on the data. The yellow band represents the uncertainty in the \Resbos{} calculation arising from varying~\cite{ScaleVariations} the QCD scales, the non-perturbative parameter $a_Z$, and PDFs.

The ratio of the predictions of \Resbos\ for the $Z$-boson mass peak and for \mody~$<$~2.4 to the combined Born-level data for $(1/\sigma)\,\mathrm{d}\sigma / \mathrm{d}\phistar$ (top) and $(1/\sigma)\,\mathrm{d}\sigma / \mathrm{d}\Zpt$ (bottom). The light-green (light-blue) band represents the statistical uncertainty on the data for \phistar\ (\Zpt) and the dark-green (dark-blue) band represents the total uncertainty (statistical and systematic) on the data. The yellow band represents the uncertainty in the \Resbos{} calculation arising from varying~\cite{ScaleVariations} the QCD scales, the non-perturbative parameter $a_Z$, and PDFs.

The ratio of $(1/\sigma)\,\mathrm{d}\sigma / \mathrm{d}\phistar$ as predicted by \Resbos{} to the combined Born-level data, for the six \mody{} regions at the \Zboson{}-boson mass peak. The light-green band represents the statistical uncertainty on the data and the dark-green band represents the total uncertainty (statistical and systematic) on the data. The yellow band represents the uncertainty in the \Resbos{} calculation arising from varying~\cite{ScaleVariations} the QCD scales, the non-perturbative parameter $a_Z$, and PDFs.

The ratio of $(1/\sigma)\,\mathrm{d}\sigma / \mathrm{d}\phistar$ as predicted by \Resbos{} to the combined Born-level data, for the three \mody{} regions in the two \Mll\ regions adjacent to the $Z$-boson mass peak. The light-green band represents the statistical uncertainty on the data and the dark-green band represents the total uncertainty (statistical and systematic) on the data. The yellow band represents the uncertainty in the \Resbos{} calculation arising from varying~\cite{ScaleVariations} the QCD scales, the non-perturbative parameter $a_Z$, and PDFs.

The distribution of $(1/\sigma)\,\mathrm{d}\sigma/ \mathrm{d}\phistar$ at Born level in each region of \mody, shown as a ratio to the central rapidity region ($\mody<0.4$), for events at the \Zboson{}-boson mass peak. The data, shown as points, are compared to the predictions of \Resbos{}. The light-green band represents the statistical uncertainty on the data and the dark-green band represents the total uncertainty on the data (treating systematic uncertainties as uncorrelated between regions of \mody). The yellow band represents the uncertainty in the \Resbos{} calculation arising from varying~\cite{ScaleVariations} the QCD scales, the non-perturbative parameter $a_Z$, and PDFs.

The distribution of $(1/\sigma)\,\mathrm{d}\sigma/ \mathrm{d}\phistar$ at Born level in each region of \mody, shown as a ratio to the central rapidity region ($\mody<0.8$), for events with \Mll{} between $46 \GeV$ to $66 \GeV$ (upper plots) and $116 \GeV$ to $150 \GeV$ (lower plots). The data, shown as points, are compared to the predictions of \Resbos{}. The light-green band represents the statistical uncertainty on the data and the dark-green band represents the total uncertainty on the data (treating systematic uncertainties as uncorrelated between regions of \mody). The yellow band represents the uncertainty in the \Resbos{} calculation arising from varying~\cite{ScaleVariations} the QCD scales, the non-perturbative parameter $a_Z$, and PDFs.

The distribution of $(1/\sigma)\,\mathrm{d}\sigma/ \mathrm{d}\phistar$ at Born level in each region of \mody, shown as a ratio to the central rapidity region ($\mody<0.8$), for events with \Mll{} between $46 \GeV$ to $66 \GeV$ (upper plots) and $116 \GeV$ to $150 \GeV$ (lower plots). The data, shown as points, are compared to the predictions of \Resbos{}. The light-green band represents the statistical uncertainty on the data and the dark-green band represents the total uncertainty on the data (treating systematic uncertainties as uncorrelated between regions of \mody). The yellow band represents the uncertainty in the \Resbos{} calculation arising from varying~\cite{ScaleVariations} the QCD scales, the non-perturbative parameter $a_Z$, and PDFs.

The ratio of $(1/\sigma)\,\mathrm{d}\sigma/ \mathrm{d}\phistar$ in the \Mll{} region from $116 \GeV$ to $150 \GeV$ to that in the \Mll{} region from $46 \GeV$ to $66 \GeV$, for three regions of \mody. The data, shown as points, are compared to the predictions of \Resbos{}. The light-green band represents the statistical uncertainty on the data and the dark-green band represents the total uncertainty on the data (treating systematic uncertainties as uncorrelated between the mass regions). The yellow band represents the uncertainty in the \Resbos{} calculation arising from varying~\cite{ScaleVariations} the QCD scales, the non-perturbative parameter $a_Z$, and PDFs.

The ratio of $(1/\sigma)\,\mathrm{d}\sigma / \mathrm{d}\Zpt$ as predicted by various MC generators to the combined Born-level data, in six different regions of \Mll\ for $\mody < 2.4$. The light-blue band represents the statistical uncertainty on the data and the dark-blue band represents the total uncertainty (statistical and systematic) on the data.

The ratio of $(1/\sigma)\,\mathrm{d}\sigma / \mathrm{d}\Zpt$ as predicted by various MC generators to the combined Born-level data, in different \mody\ ranges for events at the \Zboson{}-boson mass peak. The light-blue band represents the statistical uncertainty on the data and the dark-blue band represents the total uncertainty (statistical and systematic) on the data.

The distribution of $(1/\sigma)\,\mathrm{d}\sigma/ \mathrm{d}\Zpt$ at Born level in each region of \mody, shown as a ratio to the central rapidity region ($\mody<0.4$), for events at the \Zboson{}-boson mass peak. The data, shown as points, are compared to the predictions of various MC generators. The light-blue band represents the statistical uncertainty on the data and the dark-blue band represents the total uncertainty on the data (treating systematic uncertainties as uncorrelated between regions of \mody).

The ratio of $(1/\sigma)\,\mathrm{d}\sigma / \mathrm{d}\phistar$ as predicted by various MC generators to the combined Born-level data, in three different regions of \Mll\ for $\mody < 2.4$. The light-green band represents the statistical uncertainty on the data and the dark-green band represents the total uncertainty (statistical and systematic) on the data.

The ratio of $\mathrm{d}\sigma / \mathrm{d}\Zpt$ as predicted by the \Dynnlo{} MC generator to the combined Born-level data, for six regions of \Mll from $12 \GeV$ to $150 \GeV$. Two sets of \Dynnlo{} predictions are shown, one of which includes NLO EW corrections while the other does not. The error bars on the \Dynnlo\ predictions represent the uncertainty arising from varying the QCD scales and PDFs. Additional uncertainties introduced by the inclusion of the EW corrections are at the level of 2--4\% and are always significantly smaller than the QCD scale and PDF uncertainties. Therefore for clarity these points are shown without uncertainty bars. The light-blue band represents the statistical uncertainty on the data and the dark-blue band represents the total uncertainty (statistical and systematic) on the data.