The CMS Trigger System

Abstract

The CMS experiment at CERN uses a two-stage triggering system composed of the Level-1 (L1), instrumented with custom-designed hardware boards with an output rate of 100 kHz, and the High Level Trigger (HLT), streamlined version of the offline software reconstruction that runs on the computing farm, allowing to store around 1.5 kHz of rate. New trigger algorithms and new features, as well as optimized trigger menus at both L1 and HLT are mandatory in order to be able to successfully record the events at higher data loads due to increasing luminosity and pileup at the LHC in Run 3. Many measurements and searches will profit from the updates implemented in the CMS trigger. The highlights of Run 2 CMS trigger results will be presented, together with the improvements for Run 3.