Performance of Track and Vertex Reconstruction and $b$-Tagging Studies with ATLAS in pp Collisions at $\sqrt{s}$ = 7 TeV

First 7 TeV proton-proton collisions produced by the Large Hadron Collider (LHC) at CERN have been recorded by the ATLAS experiment. The ability to accurately and efficiently reconstruct the trajectories of charged particles produced in these collisions as well as their origin, the primary event vertex, is a critical component in many analyses. This note presents results of the track and vertex reconstruction performance using the ATLAS tracking system as well as first results from algorithms used for the identification of $b$-quark jets, so-called $b$-tagging. These algorithms take advantage of displaced tracks or a displaced vertex caused by the long-lived decay of a $b$-hadron via the weak force. As a result key ingredients to $b$-tagging algorithms are the precise trajectory measurement of charged particle tracks. The distributions of the corresponding observables - track impact parameters and secondary vertices - were measured in pp collisions at $sqrt{s}$~=~7~TeV, and compared to the predictions from Monte Carlo simulation. $b$-Tagging is an important tool for various physics programs of the ATLAS experiment.