Search for H± → τν and fake τ background estimation in the ATLAS experiment

Important part of particle physics experiments at the Large Hadron Collider (LHC) at CERN concentrate on searching for potential signs of processes beyond the Standard Model. Example of such phenomena would be the discovery of the charged Higgs boson decaying into τ lepton and neutrino, that is predicted by theories such as Supersymmetry. Identification of hadronically decaying τ leptons plays a crucial role in τ -related studies and misidentification of such decays can lead to extra background events. This paper presents an overview of the H± → τν analysis based on 2015+2016 data recorded with the ATLAS detector at the LHC and shows an usage of the data-driven Fake Factor method for fake τ background modelling. The systematics associated with the method and startegy improvements for upcoming analysis using 2015-2018 dataset are also discussed.