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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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Presentation on theme: "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."— Presentation transcript:

1 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 Europhysics Conference on High Energy Physics July 21st-27th 2005, Lisboa, Portugal

2 2 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 Physics Selection at LHC Formidable task: Trigger Rejection  Bunch crossing rate 40MHz  permanent storage rate O(10 2 )Hz

3 3 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 The CMS Trigger One of the more complex electronics systems ever built! Level 1 Trigger: Hardwired processors High Level Triggers: Farm of processors Level-1 Trigger Requirements: Output: 100 kHz (50 kHz for initial running) Latency: 3  sec for collection, decision, propagation HLT designed to output O(10 2 )Hz

4 4 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 Level-1 Trigger Information from Calorimeters and Muon detectors Electron/photon triggers Jet and missing E T triggers Muon triggers Backgrounds are huge Sophisticated trigger algorithms Steep functions of thresholds Synchronous and pipelined Bunch crossing time = 25 ns Time needed for decision (+its propagation) ≈ 3  s Highly complex Trigger primitives: ~5000 electronics boards of 7 types Regional/Global: 45 crates, 630 boards, 32 board types Large flexibility Large number of electronics programmable parameters Most algorithms implemented in re-programmable FPGAs

5 5 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 Level-1 Trigger Dataflow HFHCALECAL RPCCSCDT Pattern Comparator Trigger Regional Calorimeter Trigger 4  4+4  4  (with MIP/ISO bits) MIP+ ISO bits e, J, E T, H T, E T miss Calorimeter Trigger Muon Trigger max. 100 kHz L1 Accept Global Trigger Global Muon Trigger Global Calorimeter Trigger Local DT Trigger Local CSC Trigger DT Track Finder CSC Track Finder 40 MHz pipeline, latency < 3.2  s

6 6 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05    Calorimeter Trigger Geometry  

7 7 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 L1 Electron/Photon Trigger 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/Photon 2-tower T E+ H/E Isolated Electron/Photon 2x5-crystal strips>90% energy in 5x5 (Fine Grain) Neighbor EM + Had Quiet E+ H/E Issue is rejection of huge jet background

8 8 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 L1 Jet and  Triggers Single, double, triple and quad thresholds possible Possible also to cut on jet multiplicities Also E T miss,  E T and  E T (jets) triggers Sliding window: - granularity is 4x4 towers = trigger region - jet E T summed in 3x3 regions ,  = 1.04 “  -like” shapes identified for  trigger Issues are jet energy resolution and tau identification

9 9 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 Calorimeter Trigger Rates at Rates drop sharply with trigger Et cutoff Provides ability to tune cuts to sustain rates during operation Several cuts are available to optimize efficiency versus rate QCD background rates are within target

10 10 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 Calibrated Hadron Level Jet E t (GeV) >95% at P T =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 MC  -jet E T Efficiency >95% at P t =180 GeV for  (incl. minbias) for a 1 kHz rate  efficy MC e/  E T Efficiency >95% at P T =35 GeV for e in top events (incl. minbias) For a 7kHz rate e/  efficy

11 11 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 Calorimeter Trigger Primitives 1200 Synchronization and Link Boards: ECAL & HCAL Trigger Interface

12 12 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 SORT ASICs (w/heat sinks) EISO Bar Code Input DC-DC Converters Clock delay adjust Clock Input Oscillator DC-DC Adder mezz link cards BSCAN ASICs PHASE ASICs MLUs Back Bar Code Front Regional Calorimeter Trigger Receiver Card: Electron Isolation & Clock: Jet/Summary: Receiver Mezz. Card BSCAN ASICs Sort ASICs BSCAN ASICs Phase ASIC EISO Clock Front Back

13 13 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 Full Regional Cal. Trigger Crate 18 Such Crates make up the full RCT System covering |  |<5 & 0 <  < 2 . Rear: Receiver Cards Front: Electron, Jet, Clock Cards

14 14 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 Global Calorimeter Trigger Input Module Processor Module

15 15 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 Muons at LHC Issue is p T measurement of real muons L = cm -2 s -1  < 2.1

16 16 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 L1 Muon trigger Level-1  -trigger info from: Dedicated trigger detector: RPCs (Resistive plate chambers) Excellent time resolution Muon chambers with accurate position resolution Drift Tubes (DT) in barrel Cathode Strip Chambers (CSC) in end-caps

17 17 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 L1 Muon Trigger Overview |  | < 1.2|  | < < |  ||  | < 2.1 Cavern: UXC55 Counting Room: USC55

18 18 J. 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 Finder

19 19 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 CSC Muon Trigger Overview CSC CFEB ALCT 1 of 24 CFEB 1 of 2 LVDB LV Distribution Board 1 of 5 Anode Front-end Board Cathode Front-end Board Anode Local Charged Track Board MPCMPC DMBDMB TMBTMB DMBDMB TMBTMB DMBDMB TMBTMB DMBDMB TMBTMB DMBDMB TMBTMB DMBDMB TMBTMB DMBDMB TMBTMB DMBDMB TMBTMB DMBDMB TMBTMB CCBCCB CONTROLLERCONTROLLER Peripheral Crate on iron disk Slow Control Muon Track-Finder Crate in underground counting room Trig Motherboard Muon Port Card Clock Control Board Optical Link   Start w/ wire & strip segment combinations: Wires:25ns bunch xing Strips: precision  Form “Trigger Primitives” Link into tracks Assign p T, , and  Send highest quality tracks to Global L1

20 20 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 Global Muon Trigger Overview

21 21 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05   Muon Trigger Rates vs. P t at 10 34

22 22 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 Muon Trigger Efficiency vs. P t

23 23 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 Drift Tube Track Finder Phi Track-Finder Eta Track Finder DCC

24 24 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 Drift Tube Muon Sorter Wedge Sorter Barrel Sorter

25 25 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 CSC Trigger Full Chain 4 TMB 5 TMB Track-Finder Crate: SP  CCB   MS MPC  CCB Fully Loaded Peripheral Crate

26 26 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 RPC Trigger Board

27 27 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 Global Muon Trigger Logic Board Input board (4x4  ) Logic Board Logic fwd Logic brl ROPMIP/ISO fwd MIP/ISO brl Sort 4 SCSI connectors on Logic Board 3x4 on input board

28 28 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 L1 Global Trigger  Logic combinations of trigger objects sent by the Global Calorimeter Trigger and the Global Muon Trigger Best 4 isolated electrons/photonsE T, ,  Best 4 non-isolated electrons/photonsE T, ,  Best 4 jets in forward regionsE T, ,  Best 4 jets in central regionE T, ,  Best 4  -JetsE T, ,  Total E T  E T Total E T of all jets above thresholdH T Missing E T E T missing,  (E T missing ) 12 jet multiplicities N jets (different E T thresholds and  -regions) Best 4 muonsp T, charge, , , quality, MIP, isolation  Thresholds (p T, E T, N Jets )  Optional topological and other conditions (geometry, isolation, charge, quality)  128 algorithms running in parallel

29 29 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 Level-1 Trigger table (2x10 33 ) TriggerThreshold (GeV) Rate (kHz)Cumulative Rate (kHz) Isolated e/  Di-e/  Isolated muon Di-muon Single tau-jet Di-tau-jet jet, 3-jet, 4-jet177, 86, Jet*E T miss 88* Electron*jet21* Min-bias TOTAL16.0

30 30 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 Level-1 Trigger table (10 34 ) TriggerThreshold (GeV) Rate (kHz)Cumulative Rate (kHz) Isolated e/  Di-e/  Isolated muon Di-muon Single tau-jet Di-tau-jet jet, 3-jet, 4-jet250, 110, Jet*E T miss 113* Electron*jet25* Muon*jet15* Min-bias TOTAL33.5

31 31 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 VME interface PSB GTL6U GTL_CONV Global Trigger Crate

32 32 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 Trigger Control System Board

33 33 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 High-Level Trigger Runs on large CPU farm Code as close as possible to offline reconstruction Selection must meet CMS physics goals Output rate to permanent storage limited to O(10 2 )Hz Reconstruction on demand Reject as soon as possible Trigger “Levels”: Level-2: use calorimeter and muon detectors Level-2.5: also use tracker pixel detectors Level-3: includes use of full information, including tracker “Regional reconstruction”: e.g. tracks in a given road or region

34 34 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 HLT selection: , , jets and E T miss Muons Successive refinement of momentum measurement; + isolation Level-2: reconstructed in muon system; must have valid extrapolation to collision vertex; + calorimeter isolation Level-3: reconstructed in inner tracker; + tracker isolation  -leptons Level-2: calorimetric reconstruction and isolation Level-3: tracker isolation Jets and E t miss Jet reconstruction with iterative cone algorithm E T miss reconstruction (vector sum of towers above threshold)

35 35 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 HLT selection: electrons and photons Level-2 Level-3 Level-1 Level-2.5 Photons Threshold cut Isolation Electrons Track reconstruction E/p, matching (  ) cut ECAL reconstruction Threshold cut Pixel matching Issue is electron reconstruction and rejection Higher E T threshold on photons Electron reconstruction key is recovery of radiated energy Electron rejection key tool is pixel detector

36 36 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 HLT Summary: 2x10 33 cm -2 s -1 TriggerThreshold (GeV) Rate (Hz)Cuml. rate (Hz) Inclusive electron2933 Di-electron17134 Inclusive photon80438 Di-photon40, Inclusive muon Di-muon7472 Inclusive tau-jet86375 Di-tau-jet jet * E T miss 180 * jet OR 3-jet OR 4- jet 657, 247, Electron * jet19 * Inclusive b-jet Calibration etc10105 TOTAL105

37 37 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 HLT performance — signal efficiency With previous selection cuts ChannelEfficiency (for fiducial objects) H(115 GeV)  77% H(160 GeV)  WW*  2  92% H(150 GeV)  ZZ  4  98% A/H(200 GeV)  2  45% SUSY (~0.5 TeV sparticles)~60% With R P -violation~20% W  e 67% (fid: 60%) WW 69% (fid: 50%) Top  X 72%

38 38 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 DAQ and Filter Farm Preserie

39 39 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 Summary The CMS Trigger System is close to become reality after a long period of simulation studies, hardware prototyping and system construction The CMS trigger design meets the challenging LHC requirements: Large rate reduction High efficiency for signal events Wide inclusive selection (open to the unexpected) Huge flexibility allowing future adaptation to the unknown

40 40 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 Reserve

41 41 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 Synchronous pipelined system (40 MHz) trigger boards TRB server board SB to Sector Collector 8 cm 16 cm 2 metres Drift Tube local-trigger

42 42 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 Global Muon Trigger Efficiencies DT CSC RPC GMT smart GMT OR GMT AND GMT smart Muon Trigger Efficiency GMT Efficiency Optimal combination high efficiency, small rate AND SMART OR Rate kHz for 14 GeV    GMT Option Rates for L=2x10 33 cm -2 s - 1

43 43 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 RPC Trigger Algorithm Pattern of hit strips is compared to predefined patterns corresponding to various p T Implemented in FPGAs

44 44 J. Varela, CMS Trigger, HEP2005, Lisbon, July 05 Example: Two leptons back-to-back in , opposite charge, with missing Et above threshold  An algorithm is a logical combination of trigger objects satisfying defined threshold, topology and quality criteria  There are 128 algorithms running in parallel. Global Trigger Algorithms + -.AND. E T tot E T Thresh e/ .OR..AND. E T tot E T Thresh > Particle condition for muons Particle condition for Et miss Particle condition for Et miss Particle condition for e/    >


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