Determination of Fake Electrons, Muons and Taus in the $tbH^+$ Search for the 2lSS1tau Channel Using Template Fit Method - Summer Student Report

This study contributes to the search for the charged Higgs boson $tbH^+$. In this search with two same-sign electrically charged light leptons and one hadronically decaying tau ($2\ell$SS1$\tau$ channel), the $t\bar t$, $t\bar t W$, and $t\bar tZ$ backgrounds are dominant for fake lepton contributions. The estimation of fake events for these backgrounds by a data-driven method is particularly important. For the data-driven background determination, the Template Fit method is used. The resulting normalization factors including statistical and systematic uncertainties, for fake light lepton events from heavy flavour decays are $0.84\pm 0.15$ for electrons, $0.94\pm 0.08$ for muons, and $1.05\pm 0.02$ for taus.