1 Varela, CMS Trigger, HEP2005, Lisbon, July 05 CMS Trigger System CMS Trigger System J. Varela LIP/IST-Lisbon & CERN on behalf of the CMS collaboration HEP2005 International Europhysics Conference on High Energy Physics July 21st-27th 2005, Lisboa, Portugal
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1 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 CMS Trigger System J. Varela LIP/IST-Lisbon & CERN on behalf of the CMS collaboration HEP2005 International.
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1J. Varela, CMS Trigger, HEP2005, Lisbon, July 05
CMS Trigger SystemCMS Trigger System
J. Varela
LIP/IST-Lisbon & CERN
on behalf of the CMS collaboration
HEP2005 International Europhysics Conference on High Energy Physics
Electromagnetic trigger based on 3x3 trigger towers
• Each tower is 5x5 crystals in ECAL (barrel; varies in end-cap)
• Each tower is single readout tower in HCAL
Trigger threshold on sum of two towers
Electron/Photon2-tower T
E + H/E
Isolated Electron/Photon2x5-crystal strips>90%energy in 5x5 (Fine Grain)Neighbor EM + Had Quiet
E + H/E
Issue is rejection of huge jet background
8J. Varela, CMS Trigger, HEP2005, Lisbon, July 05
L1 Jet and L1 Jet and Triggers Triggers
Single, double, triple and quad thresholds possible
Possible also to cut on jet multiplicities
Also ETmiss, ET and ET(jets) triggers
Sliding window:- granularity is 4x4 towers = trigger region- jet ET summed in 3x3 regions , = 1.04
“-like” shapes identified for trigger
Issues are jet energy resolution and tau identification
9J. Varela, CMS Trigger, HEP2005, Lisbon, July 05
Calorimeter Trigger Rates at 10Calorimeter Trigger Rates at 103434
Rates drop sharply with trigger Et cutoff
Provides ability to tune cuts to sustain rates during operationSeveral cuts are available to optimize efficiency versus rateQCD background rates are within target
10J. Varela, CMS Trigger, HEP2005, Lisbon, July 05
Calibrated Hadron Level Jet Et (GeV)
>95% at PT =286, 232, 157, 106 GeV for
individual 1,2,3,4 jet triggers (incl. minbias)
(~0.5 kHz rate each totaling ~2 kHz)
Calorimeter Trigger Efficiency
0
0.2
0.4
0.6
0.8
1
0 50 100 150 200 250 300MC -jet ET
Efficiency
>95% at Pt =180 GeV
for (incl. minbias) for a 1 kHz rate
efficy
0
0.2
0.4
0.6
0.8
1
0 50 100 150 200 250 300
Efficiency
QCDCMSIM 116 ORCA 4.2.0
(With minimum bias)L = 1034 cm-2 s-11-Jet Et 250 GeV
286.5
2-Jet Et 200 GeV
232.5
3-Jet Et 100 GeV
157.5
4-Jet Et 80 GeV
106.5
QCD jet efficiency for | |<5
0
0.2
0.4
0.6
0.8
1
0 10 20 30 40 50 60 70 80 90 100MC e/ ET
Efficiency
>95% at PT =35 GeV
for e in top events(incl. minbias) For a 7kHz rate
e/ efficy
11J. Varela, CMS Trigger, HEP2005, Lisbon, July 05
Calorimeter Trigger PrimitivesCalorimeter Trigger Primitives1200 Synchronization and Link Boards: ECAL & HCAL Trigger Interface
12J. Varela, CMS Trigger, HEP2005, Lisbon, July 05
17J. Varela, CMS Trigger, HEP2005, Lisbon, July 05
L1 Muon Trigger OverviewL1 Muon Trigger Overview
|| < 1.2 || < 2.40.8 < || || < 2.1
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: UX
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: US
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18J. Varela, CMS Trigger, HEP2005, Lisbon, July 05
Track Finder Processor• Pipeline logic running at 40MHz (LHC bunch crossing frequency)• Implemented in programmable logic devices• Based on extrapolation and pattern matching methods
Drift Tubes
Phi Track Finder(Sector Processor)
Drift Tube Trigger Track FinderDrift Tube Trigger Track Finder
19J. Varela, CMS Trigger, HEP2005, Lisbon, July 05
4 SCSI 4 SCSI connectors connectors on Logic on Logic BoardBoard
3x4 on input 3x4 on input boardboard
28J. Varela, CMS Trigger, HEP2005, Lisbon, July 05
L1 Global TriggerL1 Global Trigger Logic combinations of trigger objects sent by the Global Calorimeter Trigger and the Global Muon Trigger Best 4 isolated electrons/photons ET, , Best 4 non-isolated electrons/photons ET, , Best 4 jets in forward regions ET, , Best 4 jets in central region ET, , Best 4 -Jets ET, , Total ET ET
Total ET of all jets above threshold HT
Missing ET ETmissing, (ET
missing) 12 jet multiplicities Njets (different ET thresholds and -regions) Best 4 muons pT, charge, , , quality, MIP, isolation
Thresholds (pT, ET, NJets)
Optional topological and other conditions (geometry,
isolation, charge, quality) 128 algorithms running in parallel
29J. Varela, CMS Trigger, HEP2005, Lisbon, July 05