The CMS trigger system

• Main Authors: Apyan, Aram (Author), Barbieri, Richard Alexander (Author), Baty, Austin Alan (Author), Bierwagen, Katharina (Author), Brandt, Stephanie Akemi (Author), Busza, Wit (Author), Cali, Ivan Amos (Author), Demiragli, Zeynep (Author), Di Matteo, Leonardo (Author), Gomez-Ceballos, Guillelmo (Author), Goncharov, Maxim (Author), Gulhan, Doga Can (Author), Iiyama, Yutaro (Author), Innocenti, Gian Michele (Author), Klute, Markus (Author), Kovalskyi, Dmytro (Author), Lai, Y. S. (Author), Lee, Y.-J (Author), Levin, A. (Author), Luckey Jr, P David (Author), Marini, Andrea Carlo (Author), McGinn, Christopher Francis (Author), Mironov, Camelia Maria (Author), Narayanan, Sruthi A. (Author), Niu, Xinmei (Author), Paus, Christoph M. E. (Author), Ralph, Duncan Kelley (Author), Roland, Christof E (Author), Roland, Gunther M (Author), Salfeld-Nebgen, Jakob Maxillian Henry (Author), Stephans, George S. F. (Author), Sumorok, Konstanty C (Author), Varma, Mukund Madhav (Author), Velicanu, Dragos Alexandru (Author), Veverka, Jan (Author), Wang, J. (Author), Wang, T.W (Author), Wyslouch, Boleslaw (Author), Yang, M. (Author), Wyslouch, Victoria (Author), CMS Collaboration (Author)
• Other Authors: Massachusetts Institute of Technology. Department of Physics (Contributor), Massachusetts Institute of Technology. Department of Nuclear Science and Engineering (Contributor), Massachusetts Institute of Technology. Laboratory for Nuclear Science (Contributor)
• Format: Article
• Language: English
• Published: IOP Publishing, 2019-07-25T18:12:58Z.
• Subjects: Article
• Online Access: Get fulltext

 This paper describes the CMS trigger system and its performance during Run 1 of the LHC. The trigger system consists of two levels designed to select events of potential physics interest from a GHz (MHz) interaction rate of proton-proton (heavy ion) collisions. The first level of the trigger is implemented in hardware, and selects events containing detector signals consistent with an electron, photon, muon, τ lepton, jet, or missing transverse energy. A programmable menu of up to 128 object-based algorithms is used to select events for subsequent processing. The trigger thresholds are adjusted to the LHC instantaneous luminosity during data taking in order to restrict the output rate to 100 kHz, the upper limit imposed by the CMS readout electronics. The second level, implemented in software, further refines the purity of the output stream, selecting an average rate of 400 Hz for offline event storage. The objectives, strategy and performance of the trigger system during the LHC Run 1 are described.