The CMS Level-1 muon trigger for the LHC Run II

The CMS experiment uses a sophisticated two-level triggering system composed of hardware-based Level-1 Trigger, and a software-based High Level Trigger to select 1 kHz of events out of 40 MHz for later analysis. A new Level-1 trigger architecture improves the data taking performance at high luminosity experienced during Run II. The upgraded muon trigger increases the redundancy of the three muon detectors - Cathode Strip Chambers (CSC), Drift Tubes (DT), and Resistive Plate Chambers (RPC) - by combining information in the muon track finders with new track reconstruction, which yields a better efficiency and lower rates. The upgraded muon trigger system and the algorithms designed to select events for both precision measurements and new physics searches are described. The performance of the upgraded muon trigger system is demonstrated using proton-proton collision data collected in Run II.