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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

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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