Tracking trigger CMS

Abstract

The planned High Luminosity Phase of the LHC (HL-LHC) will increase the collision rate in the ATLAS and CMS detectors by nearly an order of magnitude beyond the maximum luminosity for which the detectors have been designed. In that scenario, the number of proton-proton interactions per bunch crossing is expected to be about 140, on average. This very high pileup environment represents a major challenge for the L1 trigger of the experiments. The inclusion of the high granularity information coming from the Silicon Tracking detectors increases the performance of traditional triggers, based on Muon and Calorimeter information only. This poses new challenges in the design and integration of the novel inner tracking detectors in both ATLAS and CMS. On one hand, this is accomplished by modules capable of transverse momentum (p T ) discrimination, to only readout hits from relatively high p T particles. A second stage performs pattern recognition and tracking at the first level trigger in a few µs, then combined with the rest of the Muon and Calorimeter information. This presentation will discuss the track trigger strategies, the expected performances of L1 tracking, and use of the L1 tracks in the trigger. INFN Workshop on Future Detectors for HL-LHC,