Flavour Tagging in Hadronic $B_s^0$ Decays for the ATLAS Experiment at the Large Hadron Collider

The determination of the initial b quark content of neutral B mesons using various tech- niques of flavour tagging has been studied for the ATLAS experiment at the Large Hadron Collider at CERN near Geneva. This work mainly focuses on opposite side soft muon flavour tagging on the hadronic decay channels Bs0 → Ds−π+ and Bs0 → Ds−a+1 with Ds− → φ(K+,K−)π− and a+1 → ρ0(π+,π−)π+. These hadronic decay channels will be used for the measurement of the Bs0 oscillation frequency ∆ms. This study has been performed on fully simulated and reconstructed Monte Carlo data sets.