Commissioning of the ATLAS $b$-tagging algorithms using $t\bar{t}$ events in early Run-2 data

The efficient and accurate identification of $b$-jets is a vital element for much of the ATLAS Run-2 physics program. Substantial changes to both the inner tracking detector, track reconstruction and $b$-tagging algorithms, have been made between Run-1 and 2, which are expected to significantly improve the $b$-tagging performance. This note contains a first study of the modelling of the $b$-tagging in Run-2 using a topologically selected $t\bar{t}$ sample, which has a high $b$-jet purity. Good agreement is found between the data and simulated events.