Triggering on Electromagnetic Objects

1

• Triggering on Electromagnetic Objects
• (e?/?)
• at L1 L2
• Mrinmoy Bhattacharjee
• SUNY, Stony Brook
• D0 EM ID
  Vertical Review
• Thanks to
• Arnaud Lucotte, Kin Yip, Paul
  Grannis,
• Manuel Martin, Levan
  Babukhadia,
• Marc Buehler, Dave
  Toback, Dylan Casey

2
Overview

• Motivation
• D0 Trigger system (L1 L2)
• L1 EM Trigger
• Detector information at L1
• High pT EM trigger low pT di-electrons
• ? Algorithm
• Timing
• ? Efficiencies Rates
• L2 EM Trigger
• Detector information at L2
• High pT EM trigger low pT di-electrons
• ? Algorithm
• Timing
• ? Efficiencies Rates
• Summary

3
Motivation

• Run II peak inst.lum. 2 ? 1032cm2s-1
• Total accumulated data ?2 fb-1
• Measurements with High PT e?/?
• ? ?Mt lt 3.0 GeV/c2
• ? ??ttbar/?ttbar 10
• ? anomalous properties of top
• (? 8.0pb/4.2pb pp?ttX /pp?t or tX)
• ? ?Mw 40MeV/c2
• ? sin2?W from Z asymmetry
• ? pdf from W asymmetry
• fwd e-s improve MW systematic (RunI)
• (1.6?106 W ? e? / 160 ?103 Z ? ee)
• ? QCD with WZ
• ? qqbar ? W? WW?
• trilinear couplings
• radiation zero effect

4
Motivation

• B Physics with electrons
• ? ? bbar 100 ?b
• ? CP violation in Bd ? J/?Ks system
• ? Bs mixing
• ? Rare B decays
• ? Measurements on Bc meson
• Low pT e-/? from ?, ? Drell Yan
• Accumulate large samples of
  e?/?
• High signal efficiency/background rejection
• Possible with (trk - energy) matching
• ? Calorimeter (energy threshold)
• ? CFT, CPS, FPS SMT (tracking)

5
L1 L2 Trigger Configuration

• 
  Level 1 Level 2
  
• 
  
  
• 
  
• F
• E
  
• L1 Accept
• 
  
• Expect 128 Trigger Terms
  to go to 256

Input 7MHz output 7KHz time 4.2?s
Input 7KHz output 1KHz time 100??s 5 dead time
Silicon
L2 STT
CFT Ax
L2 CTT
L1CFT, CPS

CPS Ax
L2 CPS
L2 Global CalPSCFT FORM 128 TriggerTerms
CPS St
FPS
L1 FPS
L2 FPS
CAL
L1 CAL
L2 CAL
L1 Muo
Muon
L2 Muo
L1 Trigger Framework combine EM Tower,
track/cluster FORM 128 TriggerTerms
6
Challenges

• Major Challenge
• Input Rate to L1 7.6MHz at 1032cm-2s-1
• 
  
• ltpTgt e- for J/??ee- ltpTgt e- for W,Z top
  2.7 GeV/c central
  decays
• 3.1 GeV/c forward 30-40GeV/c
• Low threshold in CAL Although threshold
  high
• ? high QCD rate S/B 1/50,000

7
Definition of EM object (e-/?)

• 
  
• e? CFT trk CPS
  cluster
• CCEM
  Trigger Tower
• ? No Trk CPS cluster
• CCEM
  Trigger Tower
• e? MIP FPS clust
• ECEM
  Trigger Tower
• ? No MIP FPS cluster
• ECEM
  Trigger Tower

Central Region
Forward Region
8
L1 Tracking with CFT

• Inner most tracking device at L1 is CFT
  (??1.5)
• 
  
  
• CFT divided into 80 sectors 4.5o wide
• Fibers shared between nearest sectors
• to allow for bending in magnetic field
• Tracking Algorithm at Digital FE (FPGAs)?
• ? Allowed trajectories computed
  analytically for

Sector boundary
Track
H
CFT Sector 1
A
CFT Sector 2
9
L1 CFT Tracking ( of eqns, binning)

• Neqn ? 1/pT per sector (? 16K eqns)

10
L1 Energy Clustering with CPS FPS

• CPS next on path of EM particle (??1.5)
• 3 layers of nested triangular strips
  (1280/layer)
• 1 Axial Layer, strips to z-axis
• 2 Stereo Layers, strips at 230
• Preceded by Solenoid 1X0 Pb (?2X0)
• CPS divided into 80 sectors 4.5o wide (same as
  CFT)
• At L1 only Axial strips used
• FPS available at L1 in 1.6???2.5
• FPS divided into N/S, each side 16 ?
  sectors
• 4 Layers of nested triangular strips 2X0
  Pb
• 2 layers infront (MIP) of Pb 2 behind (shower)
• layers has strips making 22.50 (U V)
• MIP deposition front of Pb coincident with
  EM shower behind used to trigger on e-/?

11
L1 Cluster Finding ?lt1.5 (CPS)

• Clustering Algorithm at Digital FE (FPGAs)?
• Contiguous strips gt Threshold forms a clusters
• Two separate thresholds used for clustering
• 2-5 MIPs (low) for low pT electrons
  (J/??ee)
• 5-10 MIPs (high) for high pT electrons
  (W,Z,top)
• Only Axial strips used for L1 triggering
• xxLLHLxx is one 1 high cluster (NOT 2 lows 1
  high)
• Number of clusters/layer?

3 MIPs
5 MIPs
12
L1 Cluster Finding 1.6lt?lt2.6 (FPS)

• Clustering Algorithm at Digital FE (FPGAs)?
• Contiguous strips gt Threshold forms a
  clusters
• Two separate thresholds used for clustering
• 3-5 MIPs (low) for low pT electrons
  (J/??ee)
• 5-10 MIPs (high) for high pT electrons
  (W,Z,top)
• Cluster confirmed by MIP deposition
  (?0.3MIPs)
• 7 strip wide window centered at cluster
  center
• detector origin
• Number of shower clusters/layer?

3 MIPs
5 MIPs
13
L1 From DFE to L1 CFT/CPS, FPS L2

• Info sent to L1 CFT/CPS ?
• of (?) tracks per pT bin with hi/low/NO CPS
  axial tag
• of isolated tracks ?pT of all tracks
• Info sent to L1 FPS ?
• of U/V clusters (hi/low) with/without MIP
  hit
• Info sent to CFT L2?
• list of 6 tracks per pT (46 max per quadrant)
• Low pT (?3GeV/c) H layer hit (A-H)
  offset reported
• High pT (?3GeV/c) H layer hit pT
  reported
• Track ALSO matched to hi/low CPS Axial
  cluster
• Info sent to CPS L2?
• From CPS Axial (48 max per Quadrants)
• Axial cluster list with address and width (high
  low)
• Axial clusters matched to () CFT tracks
  in ?3 strips
• Track pT if present
• For CPS Stereo (48 max per N/S U/V)
• Stereo cluster list with address
  width (high low)
• Info sent to L2 FPS (48 max per N/S U/V)?

14
L1 Tracking Clustering efficiency

• CFT alone
• efficiency ?90
• FPS alone
• efficiency ?98
• rejection e/? ?3

15
L1 Calorimeter

• Task Performed at L1 (Preamps Analog ?)
• Trigger towers (TT) are 0.2?0.2 in ?????
• TTs gt 2.5, 5, 7 10GeV used as seed
• L1 EM ET rounded in 0.25GeV steps
• L1 Total ET truncated in 0.5GeV steps
• Information available at L1
• (1) For each ref set ? ? TTs gt Threshold
  (all ??)
• (2) ?EM ET / ? Had ET in Large Tile Area
  (LTA)
• (1 LTA 8 TTs in ? 4 TTs in ?)
• (3) Number of TTs above threshold in LTA
• TTs gt threshold for each Ref set can be made
  available for Quadrants
• (1 Quadrant 4 TTs in ? 8 TTs in ?)
• Send 64 AND/OR terms to L1 Framework

16
L1 Trigger Terms

• Trigger information from different detectors are
  sent to the Trigger Framework to be matched
  final trigger decision
• EM Trigger Terms
• TTK(n,p) CFT track pT gt p.
• TEL(n,p) CPS cluster/CFT track pT(gtp) match
  within 4.50.
• TPQ(n,q) CPS cluster/CFT track (gtlo/1.5Gev)
  match by quad.
• TNQ(n,q) CPS cluster (gtlo) by quadrant (no
  track EM).
• TDL(p,s) 2 trk/CPS cand. (pTgt1.5 or 5GeV),
  same/opp sign
• FPQ(n) FPS cluster/CAL tower(gt2.5GeV) match by
  quad.
• FQN/S(n) FPS cluster/CAL tower (gt2.5GeV) match
  by quadrant (e?).
• CEM(n,E) Cal EM tower (gt2.5,5.7,10GeV) in CC
  or EC.
• CEQ(n,q) CPS cluster/CAL Tower (gt2.5GeV)
  match by quad q.
• CER(n,E,?) 1/2 CAL EM tower gt2.5/5GeV in N,S,CC
  

17
L1 electron algorithm (high pT)

• Central (????1.6)
• 1 CPS cluster ? high matched to 1 track ?5GeV/c
  in 4.50
• 1 Calorimeter EM tower ? 7-10GeV (????1.6)
  matched to CPS cluster by quadrant
• Forward (1.6?????2.6)
• 1 FPS cluster ? high MIP confirmation
• 1 Calorimeter EM tower ? 7-10GeV (1.6?????2.6)
  matched to FPS cluster by quadrant
• Track/MIP matching to PS optional perform only
  if rates high
• 
  

??1.0
1.6 ? ??2.6
Cal EM gt7GeV
18
L1 EM trigger rates (high pT)

• Rates at L2?1032cm2/s
• Cluster/Track CCAL Quadrant match
• Cluster ECAL Quadrant match
• CEM(1,10,C) 200 W
  mass, QCD ?
• CEM(1,7,C)CEQ(1)TNQ(1) 62
  QCD ?
• CEM(1,10,C)TEL(1,5) 3 W
  mass, WZ ?
• CEM(1,10,N/S) 690 EC W
  mass
• CEM(1,10,N/S)FQN(1) 400 FWD EM
• CEM(1,10,N/S)FPQ(1) 200 EC W
  mass
• Rates highly dependent on thresholds in CAL
• Quadrant matching give ?2-4 in rates rejection

??1.0
19
L1 Trigger timing issues

• FE is 32 deep pipe line
• L1 Trigger
• L1 decision conveyed to AFE in 25 crossings
• Upon L1 accept AFE/DFE send L2 data
• 4.8?s deadtime due to SVX readout empty
  pipeline
• Readout to L2

20
L2 EM Trigger

• Advantages at L2 are
• (1) Large decision time 100?sec
• (2) Finer detector information available
• -- clustering in PS
• -- clustering in CAL
• (3) Due to more time finer matching can be
• performed
• -- L1 CAL/PS matching in quadrant
• -- L2 CAL/PS match within 0.2?0.2
• in ?????

21
L2 CAL Preprocessor

• L1 EM Trigger based on following reference set
• 2.5, 5, 7 10 GeV ET
• (1) L2 uses TTs above low threshold ref. set
• (2) Find 2nd. Maximum in 3?3 around seed
• (3) ETEM ETEMseed ET2nd gt Thr
• (4) EMF ETEM/(ETEMETHAD)
• (5) TISO ? ET(EMHad)/ETEM ( 3?3 ? -
  seed )
• ETEM/?ET(EMHAD) (3?3 ? includes seed)

22
L2 CAL Efficiency, Rates Timing

• (In 1.6?????2.6)
• L1 seed tower ?7GeV / ?10GeV
• ETEM ? 10GeV / 12GeV
• EMF ? 0.85
• TISO ? 0.4
• pT 15Gev/c 20GeV/c
  32.5GeV/c
• L2/L1 93.3 99.5 100.0
• 86.0 100.0 100.0
  
• Dijet Rates
• L1(1,7GeV) L2(1,10GeV) L2(1,12GeV)
• _at_2E32 900Hz 145Hz 90Hz
• L2 CAL Timing (available 50?sec)
• L2 Seed cut 0.5GeV 1.0GeV 1.5GeV 2.0GeV
• of seeds 77 19 10
  7

23
L2 CPS Preprocessor

• At L2, CPS provides 3D point combining X,U,V
• Input to L2PP
• Axial cluster address, width
  threshold (h/L),
• tracks pT if present
• Stereo cluster address, width threshold
  (H/L)
• Algorithm
• Hit U,V ? Xuv (lt/1280) Zuv (125cm)
• Xuv -True X within 10 Strips (0.05 in ?)
• Calculate ? from parameterization vs. Zuv (0.004
  in ?)
• Calculate ? from Axial hit strip
• Bin CPS ?,? into 0.25?0.25 for CAL matching at L2
  Global

24
L2 FPS Preprocessor

• At L2, FPS provides 3D point combining U V
• Input to L2PP
• Stereo cluster address, width threshold
  (H/L), MIP bits
• Algorithm
• ? parameterized as hit U V
• ? parameterized as hit U - V
• Confirm ?? as valid (within FPS detector)
• Bin FPS ?,? into 0.250.25 for CAL matching at
  L2 Global
• OUTPUT of L2 FPS
• HEADER Cluster Count
• DATA Cluster ? bin, Cluster ? bin,
• HiLo, MIP Bit pattern

25
L2 Preshower Timing

• Available 50?sec
• Timing ? number of clusters

5MIPs
3MIPs
CPS
FPS
26
L2 STT CTT Preprocessor

• No STT
• L1CFT to L2CTT (Quadrants)
• Converts L1 pT information to track pT (lookup
  table)
• Extrapolates H layer ? to ?EM3
• Merge track lists order in pT convert to L2
  object Send info to L2Global upto 184 tracks
• With STT
• L1CFT to STT sextant boards
• 48 tracks per sextant
• covers 60o in ? overlap region allow for
  track bending
• ordered in pT bin
• Sextant boards to L2STT
• 46 tracks per sextant
• Matches CTT tracks to SMT clusters and refit
• get track pT ?,?, dE/dX b
• send tracks to L2CTT in 12 cables 30o in ?
• L2STT send tracks to L2CTT
• Merge 12 track lists pT

27
L2 CTT Timing

• L2 Preprocessor Time depends on of tracks
• Time taken to make L2 objects, sort them in pT
• output them to L2Glb
• Ntrk 0 1 2 4 8 16 32
  64
• Time(?s) 0.8 1.3 1.9 3.1 5.7 11.8 27.8
  78.8

28
L2 electron algorithm (high pT)

• Central (????1.6) (L2 Global 50?sec)
• 1 CAL tower ?7GeV
• 1 CPS Axial cluster ? 5MIPs CFT Track tag
• CPS 3D match of X,U,V ? ?, ?
• (1) Axial ,U, V 5MIPs
• (2) Axial 5MIPs U,V 3MIPs
• Different detector info combined at L2 Global
• CPS-CAL match within 0.25?0.25 in
  ?????
• 
  (Z ? ee, 93.7)
• (1) efficiency loss for ET lt40GeV
  (WJets, 84.0)
• (Z ? ee, 99.0)
• (2) regains lost electrons at low ET
  (WJets, 95.4)

29
L2 electron algorithm (high pT)

• Forward (1.6?????2.6) (L2 Global 50?sec)
• CAL Cluster (ETEM)gt 10GeV,
• CAL EMF gt/ 0.85
• CAL Isolation lt/ 0.4
• FPS 3D match of U,V ? ?, ?
• (1) U, V high
• (2) U high V low OR vice versa
• Different detector info combined at L2 Global
• FPS, CAL matching within 0.25??0.25 in ?????
• Z ? ee 94.3 - 97.5 (HH / HL.OR.LH)

900Hz
_at_ 2?1032cm2/s
145Hz
80Hz
?2 PS-Cal match
30
B Physics di-electron trigger

• Triggering on low pT di-electrons
• Requirements
• - Low ET cut for in EM CAL (2.0 GeV)
• - Low threshold PS clusters (2.0-.5.0 MIPs)
• - Low pT track/charge sign (1.5 GeV/c)
• L1 trigger
• FPS
• 2 CALEM towers gt 2.5GeV
• 2 PS candidates
• ??3 wedges
• CPS
• 2 CALEM towers gt 2.5GeV
• 2 PS candidatesTrack
• match within ?3 strips
• CAL / PS Cluster (quadrant) factor 2 QDC
  rejection

31
B Physics di-electron trigger

• L1 L2 Trigger Performance
• Central Region (CAL EMgt2.5GeV, CPSgt3MIPs)
• eff (pTgt1.5GeV) 10, Rates 50Hz
• Forward region (CAL EMgt2.5GeV, FPSgt5MIPs)
• L1 eff (pTgt1.5GeV) 10, Rates 1.0-1.5KHz
• L2 eff (pTgt1.5GeV) 4-5, Rates 50Hz

32
Summary

• L1 Trigger
• electron (pTgt5GeV) efficiency gt 95 (7-10GeV
  CAL)
• background rates 1.5 Hz (7GeV CAL thr)
• 200 - 500 Hz (10GeV CAL
  Thr)
• di-e (pTgt1.5GeV) efficiency 20(cen), 10(fwd)
• background rates 1-2kHz (cenfwd)
• PS/CAL Quadrant matching ?2-3 in rates
• L2 Trigger
• electron (pTgt5GeV) efficiency gt 95 (10GeV ETEM)
• background rates 50-100 Hz (10GeV ETEM)
• di-e (pTgt1.5GeV) efficiency 10(cen),5(fwd)
• background rates 100Hz (cenfwd)
• CAL EMF, Isolation, Invariant mass helps
• PS/CAL 0.25?0.25 in ????? match ?2-3 in rates

33
L1 CFT pT binning

34
Central Forward Preshower

• CPS
• FPS

35
Trigger Task L1

• ? L1 Calorimeter Dan Edmunds
• ? tsim_l1cal Josh K, Mary Anne C.,
  Philippe L.
• (Input CAL cells Output TTs
  AND/OR)
• ? L1 framework tsim_l1frm
• Cristian Opazo-Castillo, Beatriz Pinero
• (64 AND/OR terms from L1 CAL)
• ? CFT/CPS(axial)
• AFE/DFE Kin Yip, Fred B.
• L1 L2 COL/BC Manuel M, Juan
• ? FPS
• DFE Levan B., Manuel M.
• L1 COL/BC Satish D., Manuel M.
• L2 COL/BC Mrinmoy B. Manuel M.
• ? tsim_l1ft (CFTCPSFPS)
• Kin Yip, Levan B., Mrinmoy B., Satish D.
• ? STT Overlap sextant boards

36
Trigger Task L2

• ? L2 Global tsim_l2glb (include tools)
• Roger Moore, Dylan Casey
• (combine CAL, PS, CFT write EM objects)
  
• ? L2 STT tsim_l2stt
• Silvia R.,John H.,Wendy T.
• (perform track fitting, track pT,
  impact)
• ? L2 CAL tsim_l2cal
• Robert Hirosky, Marc Beuhlar
• (cal cluster, EMF, Isolation)
• ? L2 CTT tsim_l2ctt
• Dave Toback, Drew Baden
• (track pT, impact, ?EM3, track sign)
• ? L2 PS tsim_l2prs (CPSFPS)
• Mrinmoy B.
• (cluster ??, threshold, MIP pattern,
  track tag)