Search for Pair Production of Bottom-Squarks in Final States with Hadronically Decaying Tau-leptons, b-jets and missing transverse momentum with the ATLAS Detector at the Large Hadron Collider

In this thesis a search for beyond the Standard Model physics, in particular for bottom-squark pairs in events with missing transverse momentum, b-tagged jets and hadronically decaying tau leptons is documented. The dataset used is recorded by the ATLAS detector from the proton-proton collisions at 13 TeV centre-of-mass energy at the Large Hadron Collider during the 2015-2018 period. The full dataset corresponds to an integrated luminosity of 139 fb^{-1}. No significant excess was observed, the results are compatible with the predictions of the Standard Model. Exclusion limits on bottom- squark mass are set at the 95% confidence level. Model-independent upper limits are set on the cross sections of new physics.