First Level Track Jet Trigger for Displaced Jets at High Luminosity LHC

The CMS detector for the planned high luminosity LHC run will have a new first level (L1) hardware track trigger. The impact of the L1 track trigger is explored based on the potential increase of CMS sensitivity to signals beyond the standard model in final states with multiple jets and low total transverse energy. In particular, there is currently an blind spot for lifetimes of order 1 cm in searches for new long-lived scalars $\phi$ in Higgs decays, i.e. $\text{H}(125)\to \phi\phi \to 4j$. It is found that a plausible extension of the L1 track trigger to tracks with an impact parameter of a few centimeters results in dramatic gains in the trigger efficiency. The gains are even larger for additional heavy SM-like Higgs bosons with the same decay.