The CMS Level-1 Trigger at LHC and Super-LHC

TL;DR

This paper describes the design, implementation, and validation of the CMS Level-1 trigger system at CERN, including its performance, limitations, and plans for upgrades to handle future higher luminosities at the Super-LHC.

Contribution

It presents the detailed design and validation of the CMS Level-1 trigger system and proposes a new tracking trigger for the Super-LHC upgrade.

Findings

Trigger performance matches expectations from simulations.

System successfully installed and commissioned at CERN.

Limitations identified for future luminosity increases.

Abstract

The Level-1 trigger of the CMS experiment at CERN has been designed to select proton-proton interactions whose final state includes signatures of new physics in the form of high transverse energy electrons, photons, jets, or high missing transverse energy. The Level-1 trigger system process data in a pipeline fashion at a rate of 40 MHz, has a design latency of 128 bunch crossings and an output rate of 100 KHz. The design of this system is presented with emphasis on the calorimeter triggers. After a long period of testing and validation of its performance the Level-1 trigger system has been installed and commissioned at the CMS experiment at CERN. Cosmic ray data and Monte Carlo events have been used to compare the actual performance of the trigger with expectations from off-line emulation models. Results from these studies are presented here. The limitations of this system to cope with future luminosity upgrades of the LHC, the Super-LHC, are discussed. The current CMS plan for a new CMS Level-1 trigger system at the Super-LHC is presented. The center point of the new system is a Level-1 tracking trigger which uses data from a new CMS silicon tracking detector.