1 Triggering on Electromagnetic Objects Triggering on Electromagnetic Objects (e (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 Manuel Martin, Levan Babukhadia, Babukhadia, Marc Buehler, Dave Marc Buehler, Dave Toback, Dylan Casey Toback, Dylan Casey
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1 Triggering on Electromagnetic Objects (e / ) at L1 & L2 at L1 & L2 Mrinmoy Bhattacharjee Mrinmoy Bhattacharjee SUNY, Stony Brook SUNY, Stony Brook.
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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