New trigger strategies for CMS during Run 3

Abstract

The CMS experiment at the Large Hadron Collider (LHC) features a sophisticated two-level triggering system composed of the Level 1 (L1) trigger, instrumented by custom-design hardware boards, and the High Level Trigger (HLT), a software based trigger exploiting a complete event information and full detector resolution. The CMS L1 trigger relies on separate calorimeter and muon trigger systems that provide jet, e/$\gamma$, $\tau$, and muon candidates along with calculations of energy sums to the global trigger (GT), where selections are based on the candidate kinematics. During Run 2, the L1 trigger hardware was entirely upgraded to handle proton-proton collisions at a center-of-mass energy of 13~TeV with a peak instantaneous luminosity of $2.2 \times 10^{34}$~$\textrm{cm}^{-2}\textrm{s}^{-1}$, more than double the design luminosity of the machine. In view of Run 3 of the LHC, an optimized selection at both the L1 trigger and HLT is crucial to achieving the ambitious CMS physics program. A wide range of measurements and searches will profit from the new features and strategies implemented in the trigger system. Dedicated variables and non-standard trigger techniques to target long-lived particles searches and identify unconventional physics signatures have been developed. Moreover, the implementation of new kinematic computations in the L1 GT will improve b physics measurements and resonance searches. This talk will present these new features and their expected performance measured on benchmark physics signals.