2016 and 2017 analyses, respectively, while a detailed simulation of the CMS detector is based on the  [@geant4] package. Finally, uncertainties in renormalization and factorization scale, and parton distribution functions (PDFs) have been obtained using the <span style="font-variant:small-caps;">SysCalc</span> package [@Kalogeropoulos:2018cke]. Models of direct pair production are generated with at LO precision up to the production of leptons, with their decay modeled by  8.212 and 8.230 for the analysis of 2016 and 2017 data, respectively. The CUETP8M1 [@Khachatryan:2015pea] (CUETP8M2T4 [@CMS-PAS-TOP-16-021] for ) and CP5 [@Sirunyan:2019dfx] underlying-event tunes are used with for the 2016 and 2017 analyses, respectively. The 2016 analysis uses the NNPDF3.0LO [@Ball:2014uwa] set of PDFs in generating [$\PW$+jets]{}, DY+jets, and signal events, while the NNPDF3.0NLO PDFs are used for other processes. The NNPDF3.1NLO PDFs are used for all simulated events in the 2017 analysis.

Simulated events are reweighted to match the pileup profile observed in data. Differences between data and simulation in electron, muon, and identification and isolation efficiencies, jet, electron, muon, and energy scales, and tagging efficiency are taken into account by applying scale factors to the simulation. We improve the modeling of initial-state radiation (ISR) in simulated signal events by reweighting the $\pt^{\mathrm{ISR}}$ distribution, where $\pt^{\mathrm{ISR}}$ corresponds 