Track Reconstruction Performance of the ATLAS Inner Detector at $\sqrt{s}=13$~TeV

This document summarizes the basic track reconstruction performance of the ATLAS inner detector using the first $\sqrt{s}=$ 13 TeV data from proton-proton collisions collected at the LHC. It focuses on results obtained with the baseline track quality selection used within ATLAS. Track properties such as hits on track and measured impact parameter resolution are compared between data and simulation. The properties of hits on track are also studied in the core of jets. Overall, a good agreement between data and simulation is observed, while some discrepancies remain.