Towards a Level-1 tracking trigger for the ATLAS experiment at the High Luminosity LHC

At the high luminosity HL-LHC, upwards of 160 individual proton-proton interactions (pileup) are expected per bunch-crossing at luminosities of around $5\times10^{34}$ cm$^{-2}$s$^{-1}$. A proposal by the ATLAS collaboration to split the ATLAS first level trigger in to two stages is briefly detailed. The use of fast track finding in the new first level trigger is explored as a method to provide the discrimination required to reduce the event rate to acceptable levels for the read out system while maintaining high efficiency on the selection of the decay products of electroweak bosons at HL-LHC luminosities. It is shown that available bandwidth in the proposed new strip tracker is sufficiency for a region of interest based track trigger given certain optimisations, further methods for improving upon the proposal are discussed.