Fig. 2: μ_had background normalization.

A region enriched in μ_had events is defined by selecting events with two same-sign muons. This control region is used to extract normalization factors to correct the μ_had prediction to match the data. The probe muon tranverse impact parameter (left, \(| {d}_{0}^{\mu }|\)) and transverse momentum (right, \({p}_{{\rm{T}}}^{\mu }\)) distributions in this region are shown. The data are shown by black markers and the different components contributing to this region, taken from simulation, are shown by stacked histograms. The different contributions are the primary process of interest, μ_had (μ (hadron decay)), along with the main backgrounds from events involving a top quark pair produced in association with a W or Z boson (\(t\overline{t}+V\) processes), a pair of W and/or Z bosons (Di-boson processes) and the grouping of all remaining SM processes (Other SM processes). The y-axis label includes the value that defines the scaling of the variable bin width histogram. The extracted normalization factor is applied to the μ_had prediction, along with the effect of any constraints and pulls on the systematic uncertainties from the fit to the signal region data. The bottom panels show the ratio of the data to the predicted expectation after the fit. The uncertainties on the data are the Poisson errors due to the limited size of the data sample. Blue bands indicate the ±1σ systematic uncertainties on the prediction with the constraints from the analysis fit applied. The open blue arrowheads in the ratio panel indicate points where the ratio values lie outside the y-axis range shown.