Concept of the First Level Global Trigger for the CMS Experiment at LHC

Abstract The requirements, the principles and the design of the First Level Global Trigger Processor of the CMS experiment under construction at the CERN Large Hadron Collider are described. A trigger decision based on trigger objects delivered by the detector subsystems is provided for each beam crossing at a rate of 40 MHz . The Global Trigger comprises a novel concept where event selection is not only based on objects exceeding energy or momentum thresholds but also on complex event topology, which is made possible by the availability of space, charge and quality information in the algorithm calculations. The trigger logic is largely programmable in order to satisfy all possible physics requirements.

[1]  Clara Gaspar,et al.  Architecture and performance of the DELPHI trigger system , 1992, IEEE Conference on Nuclear Science Symposium and Medical Imaging.

[2]  Nicolas Produit,et al.  First-level charged particle trigger for the L3 detector , 1991 .

[3]  R. Carlin,et al.  The trigger of ZEUS, a flexible system for a high bunch crossing rate collider , 1996 .

[4]  J. Hauser.  Primitives for the CMS Cathode Strip Muon Trigger , 1999 .

[5]  F. Sefkow,et al.  Experience with the first level trigger of H1 , 1995 .

[7]  B. G. Taylor,et al.  TTC distribution for LHC detectors , 1997 .

[8]  Anton Taurok,et al.  Implementation and synchronisation of the First Level Global Trigger for the CMS experiment at LHC , 2001 .

[9]  R. Springer,et al.  The trigger system of the OPAL experiment at LEP , 1992 .

[10]  R. Männer,et al.  Pattern Comparator Trigger (PACT) for the muon system of the CMS experiment , 1996 .

[11]  M. Lancaster,et al.  The Zeus First Level Tracking Trigger , 1992 .

[13]  A. Marchioro,et al.  Performance of the Aleph Detector At Lep , 1995 .

[14]  S. Gentile,et al.  The first level energy trigger of the L3 experiment. Description of the hardware , 1992 .

[15]  Grzegorz Wrochna,et al.  Bunch crossing identification at LHC using a mean timer technique , 1993 .

[16]  M. Abolins,et al.  The fast trigger for the DØ experiment , 1990 .

[17]  Jay Hauser,et al.  The CDF trigger , 1988 .

[18]  Alexander Kluge,et al.  The Hardware Muon Trigger Track Finder Processor in CMS - Architecture and Algorithm , 1997 .