The design and performance of the inner detector trigger for the highlevel trigger of the ATLAS experiment at the Large Hadron Colliderduring the 2016-2018 data taking period is discussed. In 2016, 2017, and2018 the ATLAS detector recorded 35.6 fb(-1), 46.9 fb(-1), and 60.6fb(-1) respectively of proton-proton collision data at a centre-of-massenergy of 13TeV. In order to deal with the very high interactionmultiplicities per bunch crossing expected with the 13TeV collisions theinner detector trigger was redesigned during the long shutdown of theLarge Hadron Collider from 2013 until 2015. An overview of thesedevelopments is provided and the performance of the tracking in thetrigger for the muon, electron, tau and b-jet signatures is discussed.The high performance of the inner detector trigger with these extremeinteraction multiplicities demonstrates how the inner detector trackingcontinues to lie at the heart of the trigger performance and isessential in enabling the ATLAS physics programme.

The ATLAS inner detector trigger performance in pp collisions at 13 TeV during LHC Run 2

Capua, M.;Mastroberardino, A.;Meoni, E.;