CMS IN-2004/009 --- TRIGGER

• Status: OK
• http://cmsdoc.cern.ch/documents/04/in/in04_009 - .pdf (811K) - .ps.Z (1835K)
• Submitter: P. Chumney
• Format: WORD
• Authors: J. Brooke, D. Cussans, G. Heath, D. Newbold, University of Bristol, UK/ P. Chumney, S. Dasu, T. Gorski M. Jaworski, J. Lackey, W. H. Smith, University of Wisconsin, Madison, WI, USA
• Abstract: An update to the interface between the CMS Level-1 Regional Calorimeter Trigger electronics crates and the Global Calorimeter Trigger (GCT) is specified. The cabling, data format, and timing are described. It includes the provision that the GCT will include the functionality of the Cluster Crate as specified in the previous document CMS IN/01-0017.

CMS IN-2004/008 --- TRIGGER

• Status: OK
• http://cmsdoc.cern.ch/documents/04/in/in04_008 - .pdf (457K) - .ps.Z (1925K)
• Submitter: P. Chumney
• Format: Mac OS 10.2.8, Word X
• Authors: E. Machado, J. Rohlf, Boston University, Boston, MA, USA/ J. Elias, FNAL, Batavia, IL, USA/ J. da Silva, J. Varela, LIP, Lisbon, Portugal/ P. Busson, LLR, Palaiseau, France/ D. Baden, T. Grassi, University of Maryland, College Park, MD, USA/ C. Tully, Princeton University, Princeton, NJ, USA/ P. Chumney, S. Dasu, M. Jaworski, J. Lackey, W. H. Smith, University of Wisconsin, Madison, WI, USA
• Abstract: The specification of the interface between the CMS Calorimeter Trigger Primitive Generator and the Level 1 Regional Calorimeter Trigger (RCT) electronics crates is updated. The cabling, data format, and timing are described. Changes from CMS Internal Note 2001/016 include the mapping and destination of the Forward Calorimeter towers, crate arrangement in the USC55 racks, and bunch crossing zero (BC0) specification instead of the ÒGap FlagÓ.

CMS IN-2004/003 --- TRIGGER ACQUISITION

• Status: OK
• http://cmsdoc.cern.ch/documents/04/in/in04_003 - .pdf (285K) - .ps.Z (8641K)
• Submitter: D. Cussans
• Format: OpenOffice .sxw
• Authors: J. Brooke, D. Cussans, University of Bristol, UK/ P. Chumney, T. Gorski, W. Smith, University of Wisconsin, Madison, USA
• Abstract: Data were passed form a CMS RCT Jet Summary Card to a prototype GCT input module. Apart from errors due to clock distribution no errors were observed.

CMS CR-2003/046 --- ACQUISITION TRIGGER

• Status: OK
• http://cmsdoc.cern.ch/documents/03/cr03_046 - .pdf (446K) - .ps.Z (4487K) + .ps
• Submitter: P. Chumney
• Format: WORD
• Authors: P. Chumney, M. Grothe, S. Dasu, T. Gorski, M. Jaworski, Wesley H. Smith, University of Wisconsin, Madison, USA/ J. Lackey, P. Robl,
• Abstract: The Compact Muon Solenoid (CMS) calorimeter regional trigger system is designed to detect signatures of isolated and non-isolated electrons/photons, jets, tau-leptons, and missing and total transverse energy using a deadtimeless pipelined architecture. This system contains 18 crates of custom-built electronics, including a backplane, boards, links and Application-Specific Integrated Circuits (ASICs). We present results from testing a completely instrumented and fully functional preproduction system. We also describe the production testing of the final system, including the custom software necessary to automate the process of testing a large quantity of high-speed and dense electronics.

CMS CR-2003/006 --- TRIGGER ACQUISITION

• Status: OK
• http://cmsdoc.cern.ch/documents/03/cr03_006 - .pdf (18803K) - .ps.Z (959K) - .warning + .ps
• Submitter: P. Chumney
• Format: Word X (Macintosh)
• Authors: P. Chumney, S. Dasu, J. Lackey, M. Jaworski, P. Robl, W. H. Smith, University of Wisconsin, Madison, USA
• Abstract: The Compact Muon Solenoid (CMS) calorimeter regional trigger system is designed to detect signatures of isolated and non-isolated electrons/photons, jets, tau-leptons, and missing and total transverse energy using a deadtimeless pipelined architecture. This system contains 18 crates of custom-built electronics. The pre-production prototype backplane, boards, links and Application-Specific Integrated Circuits (ASICs) have been built and their performance is characterized.

CMS IN-2002/019 --- TRIGGER

• Status: OK
• http://cmsdoc.cern.ch/documents/02/in02_019 - .pdf (281K) - .ps.Z (539K) + .ps
• Submitter: P. Chumney
• Format: WORD
• Authors: P. Chumney, S. Dasu, F. di Lodovico, W.H. Smith, Univ. of Wisconsin, Madison, USA
• Abstract: The physics performance using the CMS Level-1 Calorimeter trigger for initial running at a luminosity of 2x10^33 cm-2 s-1 is explored. All simulated data used for this study included proper pileup at a luminosity of 2x10^33 cm-2 s-1. For eight proposed DAQ readout rate limits from 4 to 12.5 kHz, eight corresponding sets of level-1 trigger cutoffs are examined using recently generated production data (simulated at a luminosity of 2x10^33 cm-2 s-1). Efficiencies for a variety of physics channels corresponding to these thresholds have been determined.

CMS IN-2001/042 --- TRIGGER ACQUISITION

• Status: OK
• http://cmsdoc.cern.ch/documents/01/in01_042 - .pdflog - .pdf (283K) - .ps.Z (338K) + .ps
• Submitter: P. Chumney
• Format: WORD
• Authors: P. Chumney, S. Dasu, F. di Lodovico, W. H. Smith, University of Wisconsin, Madison, U.S.A.
• Abstract: The physics performance using the CMS Level-1 Calorimeter trigger for initial running at a luminosity of 2x10^33 cm-2 s-1 is explored. For 5 proposed rate limits from 4 to 12.5 kHz, five sets of trigger cutoffs are examined, using existing Spring 2000 production data, weighted to simulate a luminosity of 2x10^33 cm-2 s-1. Efficiencies for physics channels for this set of thresholds have been determined.

CMS IN-2001/017

• Status: OK
• http://cmsdoc.cern.ch/documents/01/in01_017 - .pdflog - .pdf (120K) - .ps.Z (177K) + .ps
• Submitter: P. Chumney
• Format: MS WORD 2001
  Authors: J. Brooke, D. Cussans, G. Heath, D. Newbold, University of Bristol, UK P. Chumney, S. Dasu, M. Jaworski, J. Lackey, W. H. Smith, University of Wisconsin, Madison, USA
• Abstract: The interface between the CMS Level 1 Regional Trigger electronics crates and the Global Calorimeter Trigger is specified. Cabling, data format, and timing are described.

CMS IN-2001/016

• Status: OK
• http://cmsdoc.cern.ch/documents/01/in01_016 - .pdflog - .pdf (481K) - .ps.Z (676K) + .ps
• Submitter: P. Chumney
• Format: MS WORD 2001
• Authors: E. Machado, Boston University, USA J. Elias, FERMILAB, Batavia, USA J. da Silva, J. Varela, LIP, Lisbon, Portugal P. Busson, LPNHE, Palaiseau, France D. Baden, T. Grassi, University of Maryland, College Park, MD, USA C. Tully, Princetown University, Princeton, NJ, USA P. Chumney, S. Dasu, M. Jaworski, J. Lackey, W. H. Smith, University of Wisconsin, Madison, WI, USA
• Abstract: We specify the interface between the CMS Calorimeter Trigger Primitive Generator and the Level 1 Regional Calorimeter Trigger electronics crates. The cabling, data format, and timing are described.

CMS NOTE-2000/074

• Status: OK
• http://cmsdoc.cern.ch/documents/00/note00_074 - .pdflog - .pdf (337K) - .ps.Z (350K) + .ps
• Submitter: P. Chumney
• Format: Word 2001, Laserwriter 8, Mac OS 9.0.4
• Authors: P. Chumney, S. Dasu, W. H. Smith, University of Wisconsin, Madison, USA
• Abstract: The Compact Muon Solenoid (CMS) detector will operate at the Large Hadron Collider with luminosities of up to 10^34 cm^-2 s^-1. At L=10^34 cm^-2 s^-1, we expect 10^9 interactions per second. This rate must be reduced to 100 Hz by triggering on interesting events. The level-1 Regional Calorimeter Trigger (RCT) is a first step toward reducing the rate, while retaining physics events with high efficiency. This comprehensive study is an update of level-1 RCT simulation results using the latest CMS software tools. The new results are consistent with previous studies. The rate requirements of the data acquisition system have been met with high efficiencies for physics signals.

CMS NOTE-2000/055

• Status: OK
• http://cmsdoc.cern.ch/documents/00/note00_055 - .pdf (1195K) - .ps.Z (773K) + .ps
• Submitter: A. Nikitenko
• Format: LATEX
• Authors: S. Eno, University of Maryland, USA S. Dasu, W. Smith, University of Wisconsin, USA R. Kinnunen, Helsinki Instityte of Physics, Helsinki, Finland A. Nikitenko, CERN, Geneva, Switzerland
• Abstract: We present a Monte Carlo study of the performance of a First and a Second Level Tau trigger. These triggers are designed to be used in particular for the selection of H->2tau events with lepton plus tau-jet and two tau-jet final states. We consider the most difficult case, the two tau-jet final state in a high luminosity running scenario. We demonstrate that an acceptable background rate and a tolerable efficiency for Higgs masses of 200-500 GeV can be achieved with these type of triggers.

CMS NOTE-1999/026

• Status: OK
• ftp://cmsdoc.cern.ch/documents/99/note99_026 - .pdf (251K) - .ps.Z (581K) - .tar.Z (503K) + .ps
• Submitter: W. Badgett
• Format: LATEX and SUN
• Authors: W. Badgett, S. Dasu, M. Jaworski, J. Lackey, W. H. Smith, University of Wisconsin, Madison, USA
• Abstract: We describe the improved electron identification algorithm for the CMS level 1 calorimeter regional trigger. We specify the dataflow of the information required to identify electrons in our regional trigger system. The dataflow of both nonisolated and isolated electron/photon streams in this improved design are presented. Physics justification in terms of trigger efficiencies and background rates is given from simulation results.

CMS NOTE-1998/074

• Status: OK
• ftp://cmsdoc.cern.ch/documents/98/note98_074 - .pdflog - .pdf (485K) - .ps.Z (446K) + .ps
• Submitter: Smith
• Format: WORD
• Authors: J. Lackey, W. Badgett, S. Dasu, M. J. Jaworski, W. H. Smith, University of Wisconsin, Madison, WI, USA
• Abstract: The CMS level-1 calorimeter trigger electronics is designed to identify signatures for high-energy electrons, photons, neutrinos and jets. The calorimeter regional trigger system receives and processes digital serial data transmitted from the nearby calorimeter readout electronics on copper cables. This system consists of 19 calorimeter processor crates covering the full calorimeter. Eighteen crates are dedicated to the barrel and two endcaps. The remaining crate covers both forward calorimeters. Each calorimeter regional crate transmits to the calorimeter global trigger processor its sum Et, Ex and Ey. It also sends its 4 highest-ranked isolated and non-isolated electrons and 4 highest energy jets along with information about their location. The global calorimeter trigger then sums the energies and sorts the electrons and jets and forwards the top four calorimeter-wide isolated and non-isolated electrons and jets, as well as the total calorimeter missing and sum Et to the CMS global trigger.

CMS NOTE-1998/027

• Status: OK
• ftp://cmsdoc.cern.ch/documents/98/note98_027 - .pdf (535K) - .ps.Z (321K) - .tar.Z (283K) + .ps
• Submitter: S. Dasu
• Format: LATEX
• Authors: S. Dasu, W. Badgett, M. Jaworski, J. Lackey and W. H. Smith, University of Wisconsin, Madison, USA
• Abstract: CMS level-1 calorimeter trigger simulation results are discussed. The simulation results are obtained using CMSIM version 111 program based on the GEANT simulation of the detector. These CMSIM results compare favorably to the results from our fast simulation program used in earlier studies. Both these results indicate that the rate requirements of the data acquisition system can be met with a reasonable safety factor of three while providing high efficiencies for high ET physics processes of interest to CMS.

CMS IN/1997 - 011

• Status: OK
• ftp://cmsdoc.cern.ch/documents/97/in97_011 - .pdf (363K) - .ps.Z (211K) + .ps
• Submitter: S. Dasu
• Format: LATEX
• Authors: S. Dahu, M. Jaworski, J. Lackey and W. H. Smith, Univ. of Wisconsin, Madison, USA
• Abstract: Implementation of the fine-grain EM ID and EM isolation algorithms within the constraints of the conceptual design proposed for the CMS level-1 calorimeter trigger is discussed. Some minor modifications to the algorithms are needed for this implementation and are checked with fast simulation program to cause no degradation in performance. The modifications suggested, not only simplify some of the neighbor data sharing in the system, but also provide primitives for tau trigger implementation. However, changes to the hardware are significant and warrant closer study. This note only indicates variations on the conceptual design that might be possible with various hardhare changes. The aim of this document is to obtain an approval on the specifications outlined here so that an engineering investigation can be made.

CMS IN-1998/022

• Status: OK
• ftp://cmsdoc.cern.ch/documents/98/in98_022 - .pdf (236K) - .ps.Z (199K) - .tar.Z (168K) + .ps
• Submitter: S. Dasu
• Format: LATEX
• Authors: S. Dasu, W. Badgett, M. Jaworski, J. Lackey and W. H. Smith, Department of Physics, University of Wisconsin, Madison, USA
• Abstract: Potential scope reductions of the CMS Calorimeter Regional Trigger are considered. The consequences of such scope reductions are studied with simulations. The scenarios considered are, a) removed HCAL trigger tower information beyond a certain eta, for the electron/photon algorithm, or b) removed calorimeter trigger system itself beyond a certain pseudo-rapidity. Finally, a study of the physics impact of a reduction in the output rate of the trigger system from 100 to 75kHz is presented.

CMS TN/96 - 066

• Status: OK
• ftp://cmsdoc.cern.ch/documents/96/tn96_066 - .pdf (2854K) - .ps.Z (1249K) + .ps
• Submitter: S. Dasu
• Format: LATEX
• Authors: S. Dasu and W. H. Smith, University of Wisconsin, USA
• Abstract: We present a study of the CMS level-1 jet trigger comparing the baseline non - overlapping 4 x 4 trigger tower region algorithm with single tower and overlapping 8 x 8 trigger tower region algorithms. The results indicate that the baseline algorithm has the best performance for the physics signals studied.

CMS TN/96 - 021

• Status: OK
• ftp://cmsdoc.cern.ch/documents/96/tn96_021 - .pdf (270K) - .ps.Z (131K) + .ps
• Submitter: J. Varela
• Format: WORD
• Authors: R.Nobrega, LIP, LISBON, Portugal/ J.Varela, CERN
• Abstract: Pythia and Cmsim simulation packages were used to estimate the performance of the CMS single and double electron/photon trigger algorithms. The trigger parameters are fine-tuned to provide a required efficiency, and the corresponding trigger rates are computed in a number of situations.

CMS TN/96 - 010

• Status: OK
• ftp://cmsdoc.cern.ch/documents/96/tn96_010 - .pdf (53K) - .ps.Z (48K) + .ps
• Submitter: J. Varela
• Format: WORD
• Authors: J.Varela, CERN & CMS Calorimeter Trigger Group
• Abstract: This document contains the specifications of the CMS baseline calorimeter trigger algorithms. Detailed information on the physics performance of the algorithms can be found in the technical notes listed at the end of the document. The present specifications provide the basis for further simulation studies with the aim of refining its details. It also provide the basis for the design studies, prototype developments and beam tests to be carried out in 1996-98. These specifications are preliminary and may be modified as a result of the foreseen tests and technical developments.

CMS TN/95 - 183

• Status: OK
• ftp://cmsdoc.cern.ch/documents/95/tn95_183 - .pdflog - .pdf (236K) - .ps.Z (115K) + .ps
• Submitter: S. Dasu
• Format: LATEX
• Authors: S. Dasu, J. Lackey, W. H. Smith, W. Temple, University of Wisconsin, Madison, USA
• Abstract: We examine the efficiency and rates of the CMS Calorimeter Level 1 Trigger as presented in the CMS Technical Proposal for selecting the events needed for use in the CMS physics program described in the Proposal. Specific signals investigated include top decays to electrons, Standard Model Higgs decays o electrons and photons, signals from SUSY Higgs, and Gluino production. A variety of masses and SUSY parameters are investigated. The efficiencies are studied at the luminosity 10/33 cm-2 s-1 or 10/34 cm -2 s-1 depending on the expected rate of events as assumed in the CMS Technical proposal. A single set pf Level 1 Calorimeter energy thresholds for electrons, jets and missing energy is selected to provide a 15 kHz rate at each of the two luminosity settings considered. It is shown that this set of cuts provides sufficiently high efficiency and satisfies CMS physics goals as stated in the Technical Proposal. We also explore the rate of B physics signals that pass this high pt trigger.

CMS TN/95 - 111

• Status: OK
• ftp://cmsdoc.cern.ch/documents/95/tn95_111 - .pdf (898K) - .ps.Z (348K) + .ps
• Submitter: S. Dasu
• Format: LATEX
• Authors: S. Dasu, J.Lackey, W.E.Smith, W. Temple, WISCONSIN
• Abstract: The Level 1 missing transverse energy trigger for the CMS detector at the LHC is investigated. At a luminosity of $10^{34} cm^{-2} s^{-1}$, a fast parametrized simulation predicts a Level 1 Trigger rate, with an 80 GeV nominal threshold and $|\eta|&lt2.6$, of 2.4 kHz; for $|\eta|&lt5$, the trigger rate is 760 Hz. For $|\eta|&lt2.6$, with a nominal threshold of 80 GeV, the missing transverse energy trigger achieves 54.2\% efficiency for SUSY events of any missing $E_t$ value with an efficiency of 90\% only when the true missing E$_t$ of the SUSY events is above 193 GeV. For $|\eta|&lt5$, with a nominal threshold of 80 GeV, 90\% efficiency for SUSY events is achieved only when the true missing E$_t$ of the SUSY events is over 171 GeV. The poor efficiency turn on is because the missing E$_t$ measured by the Level 1 Trigger minus the true missing E$_t$ of the SUSY events is found to have a Gaussian distribution with a $\sigma$ of 46 GeV and a mean of -36 GeV for $|\eta|&lt2.6$, and with a $\sigma$ of 42 GeV and a mean of -36 GeV for $|\eta|&lt5$. Some slightly different missing transverse energy trigger schemes do not improve the performance significantly. These rates, efficiencies, and resolutions are different from those found simply using the particles generated by Pythia. The effects of different detector effects on the rates and resolutions are explained. With a 2.4 kHz rate and a cutoff of 80 GeV, the missing transverse energy trigger alone provides 54.2\% efficiency for SUSY events for $|\eta|&lt2.6$. Jet and total energy triggers supplement the missing E$_t$ trigger to provide 69.4\% efficiency for SUSY events for $|\eta|&lt2.6$.

CMS TN/94 - 285

• Status: OK
• ftp://cmsdoc.cern.ch/documents/94/tn94_285 - .pdf (661K) - .ps.Z (236K) + .ps
• Submitter: W. Smith
• Format: LATEX
• Authors: S. Dasu, J. Lackey,W.H. Smith, W. Temple, Univ. of Wisconsin, Physics Department, Madison, USA
• Abstract: The level 1 calorimeter trigger system for the CMS detector at the LHC collider must provide a deadtimeless, pipelined trigger that implements simple algorithms which satisfy the physics efficiency and data rate requirements. In this note we examine the performance of a conceptual design and that of an alternate algorithm for the electron trigger. The algorithms account for energy sharing between neigh boring towers and perform hadronic, and optionally, electromagnetic isolation. Through extensive simulation of the level 1 calorimeter trigger, we have determined the background rates and efficiencies of triggers for electrons, photons and jets.

CMS TN/94 - 284

• Status: OK
• ftp://cmsdoc.cern.ch/documents/94/tn94_284 - .pdf (532K) - .ps.Z (569K) + .ps
• Submitter: W. Smith
• Format: LATEX
• Authors: J. Lackey, S. Dasu, M. Jaworski, D. Panescu, W.H. Smith, W. Temple, University of Wisconsin, USA
• Abstract: The CMS Trigger and Data Acquisition system is designed to operate at the nominal LHC design luminosity of 10 (34), where an average of 20 ineslastic events occur at the beam crossing frequency of 25 nsec