Data-Driven Fake Tau Backgrounds in the Search for SH → bb τ_hτ_h Decays at the ATLAS Experiment

Searches for extended Higgs sectors, including processes where X → SH with S → b b̄ and H → τ⁺τ⁻, are well-motivated and a key part of the ATLAS search program. This work is part of the first ATLAS analysis targeting SH → bbττ, and it is strongly motivated by the established ATLAS HH → bbττ searches. A major challenge arises from jets misidentified as hadronic tau leptons ("fake taus"), which are modeled using data-driven methods. In this project, we evaluate the modeling of the fake-tau background estimates developed in the HH → bbττ framework when selections motivated by the SH → bbττ search are applied. The bbττ final state is experimentally accessible; here we focus on the fully hadronic topology (bb τhτh).