CMS IN/1997 - 011

• Status: OK
• ftp://cmsdoc.cern.ch/documents/97/in97_011 - .pdf (363K) - .ps.Z (211K) + .ps
• Submitter: S. Dahu
• 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 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.