Combined L1 Trigger Tracker studies for HL-LHC upgrade

Abstract

The high-luminosity upgrade of the Large Hadron Collider (HL-LHC) scheduled for 2022-2023 focuses on increasing the intensity of proton beams to produce a higher number of collisions per second, making it easier to collect large amount of data needed for the studies on the Higgs sector. The upgrade also includes improvements on the detectors sensitivity to rare processes presenting signs of new physics, which could hold keys to the origins of dark matter and baryon asymmetry in the Universe, non-vanishing neutrino mass and many other phenomena not explained by the Standard Model. However, many more colliding particles will substantively increase the the density and rate of particles traversing particle detectors, including the CMS experiment at the LHC, imposing a challenge on the high efficiency triggering. The trigger, which is the system responsible for ultra-fast online selection of potentially interesting data to diminish the rate of data to the level at which the data can be written to disk for offline analysis, must necessarily be upgraded to be able to properly handle the vast amount of data. The proposed upgrade of the CMS tracking system to acquire triggering capabilities is expected to address some of these difficulties, but a whole class of possible processes signifying presence of new physics via decays of long lived particles may become inaccessible to CMS. We propose and investigate a conceptually new trigger algorithm for reconstructing and measuring momenta of displaced muons using information from muon spectrometers only, which can be implemented as part of the re-design of the CMS Level-1 muon trigger for the HL-LHC to maintain CMS sensitivity to signatures with displaced muons.