For Run 3 of ATLAS significant upgrades to the capabilities of the tracking software used in the online High Level Trigger have enabled a suite of triggers specifically targeted at long-lived particles. In runs 1 and 2 tracking at the trigger was only able to reconstruct tracks from prompt particles, for Run 3 significant improvements in the performance of the tracking code have enabled this tracking to be extended to reconstruct tracks from long-lived particles. (Large Radius Tracking). The addition of LRT to the trigger has enabled new triggers which make use of this capability to reconstruct the tracks produced by the decay of an LLP. This enables significant gains in sensitivity to long-lived particles.
The development of a trigger for a long-lived scalar produced in association with a jet will be presented.