Prospects for the measurement of $B_s$ oscillations with the ATLAS detector at LHC

The capabilities of the ATLAS detector to measure the ${s}^{0}$ oscillations in proton-proton interactions at the Large Hadron Collider were evaluated. $B_{s}^{0}$ candidates in the $D_{s}^{-} \pi^{+}$ and D_{s}^{-} a_{1}^{+}$ decay modes from semileptonic exclusive events were fully simulated and reconstructed, using a detailed detector description. The sensitivity and the expected accuracy for the from unbinned maximum likelihood amplitude fits as functions of the integrated luminosity. A detailed treatment of the systematic uncertainties was performed. The dependence of the measurement sensitivity on various parameters was also evaluated.