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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, - PowerPoint PPT Presentation
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1
Triggering on Electromagnetic Triggering on Electromagnetic ObjectsObjects
(e(e//))
at L1 & L2at L1 & L2
Mrinmoy BhattacharjeeMrinmoy Bhattacharjee
SUNY, Stony BrookSUNY, Stony Brook D0 EM ID Vertical ReviewD0 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 CaseyMarc Buehler, Dave Toback, Dylan Casey
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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
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Motivation
Run II peak inst.lum. 2 1032cm2s-1
Total accumulated data 2 fb-1
Measurements with High PT e/
Mt < 3.0 GeV/c2
ttbar/ttbar ~ 10%
anomalous properties of top
( = 8.0pb/4.2pb pptt+X /ppt or t+X)
Mw ~ 40MeV/c2
sin2W from Z asymmetry
pdf from W asymmetry fwd e-’s improve MW systematic (RunI)
(1.6106 W e / 160 103 Z ee)
QCD with WZ qqbar W & WW
trilinear couplings & radiation zero effect SUSY searches
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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)
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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 4.2s
Input 7KHz
output 1KHz
time 100s
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
TriggerTermsL2 Muo
L2 STT
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Challenges
Major Challenge:
Input Rate to L1 ~ 7.6MHz at 1032cm-2s-1
<pT> e- for J/ee- <pT> 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
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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 RegionForward Region
Central RegionCentral Region
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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 pT>1.5GeV/c (equations)
Match hit patterns in all 8 layers with pre-programmed equations (anchor on H layer)
Sector boundary Track
CFT
Sector 1 CFT
Sector 2
A
H
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L1: CFT Tracking (# of eqns, binning)
Neqn 1/pT per sector ( 16K eqns)
Tracks binned in pT
pT binning gives sharper turn on than offset binning
[1.5-3.0], [3.0-5.0], [5.0-10.0], [10]Gev/c
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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-/
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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 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
These are input to L2
3 MIPs 5 MIPs
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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 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
These are input to L2
3 MIPs 5 MIPs
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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)— Stereo cluster list with address and width (high & low)
w/o MIP hit (48 max per quadrant)
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L1: Tracking & Clustering efficiency
CFT alone
efficiency 90%
FPS alone
efficiency 98%
rejection e/ 3
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L1: Calorimeter
Task Performed at L1 (Preamps & Analog )
Trigger towers (TT) are 0.20.2 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 ET / Had ET 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
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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 > p.
TEL(n,p): CPS cluster/CFT track pT(>p) match within 4.50.
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
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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 (1.62.6)1 FPS cluster high + MIP confirmation
1 Calorimeter EM tower 7-10GeV (1.62.6) matched to FPS cluster by quadrant
Track/MIP matching to PS optional; perform only if rates high
Cal EM >7GeV
||1.0 1.6 ||2.6
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L1 EM trigger rates (high pT)
Rates at L=21032cm2/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
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L1 Trigger timing issues
FE is 32 deep pipe lineL1 Trigger:
L1 decision conveyed to AFE in ~25 crossings
Upon L1 accept AFE/DFE send L2 data 4.8s deadtime due to SVX readout & empty
pipeline
Readout to L2:
Have to be completed within 36 crossings (4.8 s)
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L2 EM Trigger
Advantages at L2 are:
(1) Large decision time 100sec(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 0.20.2
in
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L2: CAL Preprocessor
L1 EM Trigger based on following reference set
2.5, 5, 7 & 10 GeV ET
(1) L2 uses TT’s above low threshold ref. set
(2) Find 2nd. Maximum in 33 around seed
(3) ETEM = ET
EMseed + ET2nd > Thr
(4) EMF = ETEM/(ET
EM+ETHAD)
(5) TISO = ET(EM+Had)/ETEM ( 33 - seed )
= ETEM/ET(EM+HAD) (33 includes seed)
Both EMF & Isolation useful in background rejection
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L2: CAL Efficiency, Rates & Timing
(In 1.62.6)
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)@2E32 900Hz 145Hz 90Hz
L2 CAL Timing (available 50sec) L2 Seed cut 0.5GeV 1.0GeV 1.5GeV 2.0GeV
# of seeds 77 19 10 7
Time s 179 46 25 18
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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)
AlgorithmHit U,V Xuv (</=1280) & Zuv (±125cm)
Xuv -True X within ±10 Strips (0.05 in )
Calculate from parameterization vs. Zuv (0.004 in )
Calculate from Axial hit stripBin CPS , into 0.250.25 for CAL matching at L2
Global
OUTPUTS of L2 CPS: HEADER: Cluster Count
DATA: Cluster bin,
Cluster bin, HiLo, Track Tag
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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
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L2: Preshower Timing
Available 50sec
Timing number of clusters
CPS Low threshold ~ 90% in 40sec (500Hz devoted)
FPS Low threshold ~ 95% in 24sec (500Hz devoted)
5MIPs3MIPs
FPS
CPS
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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 refitget track pT ,, dE/dX & b
send tracks to L2CTT in 12 cables 30o in
L2STT send tracks to L2CTT
Merge 12 track lists pT
Merge 12 track lists & order in b
Send tracks to L2Global upto 184 tracks
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L2: CTT Timing
L2 Preprocessor Time depends on # of tracksTime 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
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L2 electron algorithm (high pT)
Central (1.6) (L2 Global 50sec)
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 0.250.25 in
(Z ee, 93.7%) (1) efficiency loss for ET <40GeV (W+Jets, 84.0%)
(Z ee, 99.0%)
(2) regains lost electrons at low ET (W+Jets, 95.4%)
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L2 electron algorithm (high pT)
Forward (1.62.6) (L2 Global 50sec) CAL Cluster (ET
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 0.250.25 in
Z ee 94.3% - 97.5% (HH / HL.OR.LH)
@ 21032cm2/s
2 PS-Cal match
900Hz
145Hz80Hz
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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 FPS2 CALEM towers > 2.5GeV2 PS candidates =3 wedges
CPS2 CALEM towers > 2.5GeV2 PS candidates+Track match within 3 strips
CAL / PS Cluster (quadrant) = factor 2 QDC rejection
Level-2 trigger: - Matching: CAL / PS clusters in 0.250.25 in
- EM fraction, DR(e-,e+), M (e-,e+), DF(e-,e+),ET
ISO
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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
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Summary
L1 Triggerelectron (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 ET
EM)
background rates 50-100 Hz (10GeV ETEM)
di-e (pT>1.5GeV) efficiency ~ 10%(cen),5%(fwd)
background rates 100Hz (cen+fwd)
CAL EMF, Isolation, Invariant mass helps PS/CAL 0.250.25 in match = 2-3 in
rates
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L1: CFT pT binning
Backup 1
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Central & Forward Preshower
CPS
FPS
Backup 2
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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
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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
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