The CMS Level-1 Calorimeter Trigger Upgrade for the Run II of the LHC

The CMS experiment has implemented a sophisticated two-level online selection system that achieves a rejection factor of nearly 10 5 . The first level (L1) is based on coarse information coming from the calorimeters and the muon detectors while the High-Level Trigger combines fine-grain information from all sub-detectors. During Run II, the LHC will increase its centre-of- mass energy up to 13 TeV and progressively reach an instantaneous luminosity of 2 34 cm...