A proposed DT-seeded Muon Track Trigger for the HL-LHC

The LHC program after the observation of the candidate SM Higgs boson will continue with collisions at 13 and 14 TeV, which will help clarify future subjects of study and shape the tools needed to carry them on. Any upgrade of the LHC experiments for unprecedented luminosities, such as the HL-LHC ones, must then maintain the acceptance on electroweak processes that can lead to a detailed study of the properties of the candidate Higgs boson. The acceptance of the key leptonic, photonic and hadronic trigger objects should be kept such that the overall physics acceptance, in particular for low-mass scale processes, can be the same as the one the experiments featured in 2012. In such a scenario, a new approach to early trigger implementation is needed. One of the major steps to be taken is the exploitation of high-granularity tracking sub-detectors, such as the CMS Silicon Tracker, in taking the early trigger decision. Their inclusion into the trigger chain can be crucial in several tasks, including the confirmation of triggers in other subsystems, and the improvement of the on-line momentum measurement resolution. A muon track-trigger for the CMS experiment at the HL-LHC is presented. A back-extrapolation of DT trigger primitives is proposed in order to match tracks found at Level 1 with muon candidates. Given the better momentum resolution of the CMS silicon tracker, the crucial role of the muon trigger will be to provide good spatial information to enhance the association with Level 1 tracks. The main figures-of-merit are presented, featuring sharp thresholds and less contamination from lower momentum muons, and an expected rate reduction of a factor 5 to 10 at typical thresholds with respect to an upgrade-less scenario.