1. 1 Triggering on Electromagnetic Objects (e  /  ) at L1 & L2 at L1 & L2 Mrinmoy Bhattacharjee Mrinmoy Bhattacharjee SUNY, Stony Brook SUNY, Stony Brook D0 EM ID Vertical Review D0 EM ID Vertical Review Thanks to: Thanks to: Arnaud Lucotte, Kin Yip, Paul Grannis, Arnaud Lucotte, Kin Yip, Paul Grannis, Manuel Martin, Levan Babukhadia, Manuel Martin, Levan Babukhadia, Marc Buehler, Dave Toback, Dylan Casey Marc Buehler, Dave Toback, Dylan Casey

2. 2 Overview  Motivation  D0 Trigger system (L1 & L2)  L1 EM Trigger: Detector information at L1 High p T EM trigger & low p T di-electrons  Algorithm * Timing  Efficiencies & Rates  L2 EM Trigger: Detector information at L2 High p T EM trigger & low p T di-electrons  Algorithm * Timing  Efficiencies & Rates  Summary

3. 3 Motivation Run II peak inst.lum. 2  10 32 cm 2 s -1 Total accumulated data  2 fb -1 Measurements with High PT e  /    M t < 3.0 GeV/c 2   ttbar /  ttbar ~ 10%  anomalous properties of top (  = 8.0pb/4.2pb pp  tt+X /pp  t or t+X)   M w ~ 40MeV/c 2  sin 2  W from Z asymmetry  pdf from W asymmetry fwd e - ’s improve M W systematic (RunI) (1.6  10 6 W  e / 160  10 3 Z  ee)  QCD with WZ  qqbar  W  & WW  trilinear couplings & radiation zero effect  SUSY searches

4. 4 Motivation B Physics with electrons   bbar ~ 100  b  CP violation in B d  J/  K s system  Bs mixing  Rare B decays  Measurements on B c meson Low p T 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. 5 L1 & L2 Trigger Configuration Level 1 Level 2 F E L1 Accept Expect 128 Trigger Terms to go to 256 L1 Trigger Framework combine EM Tower, track/cluster FORM 128 TriggerTerms Input 7MHz output 7KHz time 4.2  s Input 7KHz output 1KHz time 100  s 5% dead time L1 Muo CFT Ax CPS Ax L1CFT, CPS CPS St FPS CAL Muon L1 FPS L1 CAL L2 CTT L2 CPS L2 FPS L2 CAL Silicon L2 Global Cal+PS+CFT FORM 128 TriggerTerms L2 Muo L2 STT

6. 6 Challenges Major Challenge: Input Rate to L1 ~ 7.6MHz at 10 32 cm -2 s -1 e - for J/  ee - 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. 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 Forward Region Central Region

8. 8 L1: Tracking with CFT Inner most tracking device at L1 is CFT (|  |  1.5) CFT divided into 80 sectors 4.5 o wide Fibers shared between nearest sectors to allow for bending in magnetic field Tracking Algorithm at Digital FE (FPGAs)   Allowed trajectories computed analytically for p T >1.5GeV/c (equations)  Match hit patterns in all 8 layers with pre-programmed equations (anchor on H layer) Sector boundaryTrack CFT Sector 1 CFT Sector 2 A H

9. 9 L1: CFT Tracking (# of eqns, binning) N eqn  1/p T per sector (  16K eqns)  Tracks binned in p T pT binning gives sharper turn on than offset binning [1.5-3.0], [3.0-5.0], [5.0-10.0], [  10]Gev/c

10. 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 ~ 23 0 Preceded by Solenoid & 1X 0 Pb (  2X 0 ) CPS divided into 80 sectors 4.5 o 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 & 2X 0 Pb 2 layers infront (MIP) of Pb; 2 behind (shower) layers has strips making 22.5 0 (U & V) MIP deposition front of Pb coincident with EM shower behind used to trigger on e - / 

11. 11 L1: Cluster Finding |  |<1.5 (CPS) Clustering Algorithm at Digital FE (FPGAs)  Contiguous strips > Threshold forms a clusters Two separate thresholds used for clustering 2-5 MIPs (low) for low p T electrons (J/  ee) 5-10 MIPs (high) for high p T 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  These are input to L2 3 MIPs 5 MIPs

12. 12 L1: Cluster Finding 1.6<|  |<2.6 (FPS) Clustering Algorithm at Digital FE (FPGAs)  Contiguous strips > Threshold forms a clusters Two separate thresholds used for clustering 3-5 MIPs (low) for low p T electrons (J/  ee) 5-10 MIPs (high) for high p T 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  These are input to L2 3 MIPs5 MIPs

13. 13 L1: From DFE to L1 CFT/CPS, FPS & L2 Info sent to L1 CFT/CPS  —# of (  ) tracks per p T bin with hi/low/NO CPS axial tag — # of isolated tracks &  p T 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 p T (46 max per quadrant) Low p T (  3GeV/c): H layer hit & (A-H) offset reported High p T (  3GeV/c): H layer hit & p T 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 p T 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)  —Stereo cluster list with address and width (high & low) w/o MIP hit (48 max per quadrant)

14. 14 L1: Tracking & Clustering efficiency CFT alone efficiency  90% FPS alone efficiency  98% rejection e/   3

15. 15 L1: Calorimeter Task Performed at L1 (Preamps & Analog  ) Trigger towers (TT) are 0.2  0.2 in  TTs > 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   TT’s > Threshold (all  ) (2)  EM E T /  Had E T in Large Tile Area (LTA) (1 LTA = 8 TT’s in  & 4 TT’s in  ) (3) Number of TT’s above threshold in LTA # TT’s > threshold for each Ref set can be made available for Quadrants (1 Quadrant = 4 TT’s in  & 8 TT’s in  ) Send 64 AND/OR terms to L1 Framework

16. 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 p T > p. TEL(n,p): CPS cluster/CFT track p T (>p) match within 4.5 0. TPQ(n,q): CPS cluster/CFT track (>lo/1.5Gev) match by quad. TNQ(n,q): CPS cluster (>lo) by quadrant (no track = EM). TDL(p,s): 2 trk/CPS cand. (pT>1.5 or 5GeV), same/opp sign FPQ(n): FPS cluster/CAL tower(>2.5GeV) match by quad. FQN/S(n): FPS cluster/CAL tower (>2.5GeV) match by quadrant (e+  ). CEM(n,E): Cal EM tower (>2.5,5.7,10GeV) in CC or EC. CEQ(n,q): CPS cluster/CAL Tower (>2.5GeV) match by quad q. CER(n,E,  ): 1/2 CAL EM tower >2.5/5GeV in N,S,CC

17. 17 L1 electron algorithm (high p T ) Central (  1.6) 1 CPS cluster  high matched to 1 track  5GeV/c in 4.5 0 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 Cal EM >7GeV |  |  1.01.6  |  |  2.6

18. 18 L1 EM trigger rates (high p T ) Rates at L=2  10 32 cm 2 /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. 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: Have to be completed within 36 crossings (4.8  s)

20. 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. 21 L2: CAL Preprocessor L1 EM Trigger based on following reference set 2.5, 5, 7 & 10 GeV E T (1) L2 uses TT’s above low threshold ref. set (2) Find 2nd. Maximum in 3  3 around seed (3) E T EM = E T EMseed + E T 2nd > Thr (4) EMF = E T EM /(E T EM +E T HAD ) (5) T ISO =  E T (EM+Had)/E T EM ( 3  3  - seed ) = E T EM /  ET(EM+HAD) (3  3  includes seed) Both EMF & Isolation useful in background rejection

22. 22 L2: CAL Efficiency, Rates & Timing (In 1.6  2.6) L1 seed tower  7GeV /  10GeV ETEM  10GeV / 12GeV EMF  0.85 T ISO  0.4 p T 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) @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 Time  s 179 46 25 18

23. 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 p T if present Stereo = cluster address, width & threshold (H/L) Algorithm Hit U,V  X uv (</=1280) & Z uv (±125cm) X uv -True X within ±10 Strips (0.05 in  ) Calculate  from parameterization vs. Z uv (0.004 in  ) Calculate  from Axial hit strip Bin CPS ,  into 0.25  0.25 for CAL matching at L2 Global OUTPUTS of L2 CPS: HEADER: Cluster Count DATA: Cluster  bin, Cluster  bin, HiLo, Track Tag

24. 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 0.25*0.25 for CAL matching at L2 Global OUTPUT of L2 FPS: HEADER: Cluster Count DATA: Cluster  bin, Cluster  bin, HiLo, MIP Bit pattern

25. 25 L2: Preshower Timing Available 50  sec Timing  number of clusters CPS Low threshold ~ 90% in 40  sec (500Hz devoted) FPS Low threshold ~ 95% in 24  sec (500Hz devoted) 5MIPs3MIPs FPS CPS

26. 26 L2: STT & CTT Preprocessor No STT: L1CFT to L2CTT (Quadrants) Converts L1 p T information to track p T (lookup table) Extrapolates H layer  to  EM3 Merge track lists & order in p T & convert to L2 object Send info to L2Global upto 184 tracks With STT: L1CFT to STT sextant boards 48 tracks per sextant covers 60 o in  & overlap region allow for track bending ordered in p T bin Sextant boards to L2STT 46 tracks per sextant Matches CTT tracks to SMT clusters and refit get track p T , , dE/dX & b send tracks to L2CTT in 12 cables 30 o in  L2STT send tracks to L2CTT Merge 12 track lists p T Merge 12 track lists & order in b Send tracks to L2Global upto 184 tracks

27. 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 Study performed on 233MHz board Alpha timing 1.6 factor better

28. 28 L2 electron algorithm (high p T ) 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 E T <40GeV (W+Jets, 84.0%) (Z  ee, 99.0%) (2) regains lost electrons at low E T (W+Jets, 95.4%)

29. 29 L2 electron algorithm (high p T ) Forward (1.6  2.6) (L2 Global 50  sec) CAL Cluster (E T EM )> 10GeV, CAL EMF >/= 0.85 CAL Isolation </= 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) @ 2  10 32 cm 2 /s  2 PS-Cal match 900Hz 145Hz 80Hz

30. 30 B Physics: di-electron trigger Triggering on low pT di-electrons: Requirements: - Low E T cut for in EM CAL (2.0 GeV) - Low threshold PS clusters (2.0-.5.0 MIPs) - Low p T track/charge sign (1.5 GeV/c) L1 trigger FPS 2 CALEM towers > 2.5GeV 2 PS candidates  =3 wedges CPS 2 CALEM towers > 2.5GeV 2 PS candidates+Track match within  3 strips CAL / PS Cluster (quadrant) = factor 2 QDC rejection Level-2 trigger: - Matching: CAL / PS clusters in 0.25  0.25 in  - EM fraction, DR(e-,e+), M (e-,e+), DF(e-,e+),E T ISO

31. 31 B Physics: di-electron trigger L1 & L2 Trigger Performance: Central Region (CAL EM>2.5GeV, CPS>3MIPs) eff (pT>1.5GeV) = 10%, Rates = 50Hz Forward region (CAL EM>2.5GeV, FPS>5MIPs) L1 eff (pT>1.5GeV) = 10%, Rates = 1.0-1.5KHz L2 eff (pT>1.5GeV) = 4-5%, Rates = 50Hz

32. 32 Summary L1 Trigger electron (pT>5GeV) efficiency > 95% (7-10GeV CAL) background rates 1.5 Hz (7GeV CAL thr) 200 - 500 Hz (10GeV CAL Thr) di-e (pT>1.5GeV) efficiency ~ 20%(cen), 10%(fwd) background rates 1-2kHz (cen+fwd) PS/CAL Quadrant matching  2-3 in rates L2 Trigger electron (pT>5GeV) efficiency > 95% (10GeV E T EM ) background rates 50-100 Hz (10GeV E T EM ) di-e (pT>1.5GeV) efficiency ~ 10%(cen),5%(fwd) background rates 100Hz (cen+fwd) CAL EMF, Isolation, Invariant mass helps PS/CAL 0.25  0.25 in  match =  2-3 in rates

33. 33 L1: CFT pT binning Backup 1

34. 34 Central & Forward Preshower CPS FPS Backup 2

35. 35 Trigger Task: L1  L1 Calorimeter Dan Edmunds  tsim_l1cal Josh K, Mary Anne C., Philippe L. (Input = CAL cells; Output = TT’s & 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 (CFT+CPS+FPS) Kin Yip, Levan B., Mrinmoy B., Satish D.  STT Overlap & sextant boards Brian Connoly, Manuel M.,William Lee  L1 Trigger Terms Jerry Blazey Backup 3

36. 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 (CPS+FPS) Mrinmoy B. (cluster , threshold, MIP pattern, track tag) Backup 4