SLHC Trigger Workshop – Feb. 13, 2004 1 Super LHC - SLHC LHC Detector Upgrade Dan Green Fermilab.

SLHC Trigger Workshop – Feb. 13, 2004 1

Super LHC - SLHCSuper LHC - SLHC

LHC Detector Upgrade

Dan Green

Fermilab


OutlineOutlinePhysics Basics

Z’ vsRapidity RangeMinbiasPileup and Jets

Occupancy and Radiation Dose Tracker UpgradeCalorimetryMuonsTrigger and DAQ

, sCERN-TH/2002-078 “Physics Potential and Experimental Challenges of the LHC Luminosity Upgrade”

[10x will be challenging]


Mass Reach vs LMass Reach vs L

1032

1033

1034

1035

103

104

Luminosity(/cm2sec)

MZ'

(Ge

V)

N=100 Events, Z' Coupling

2 TeV 14 TeV 28 TeV 100 TeV

The SLHC defines a decades long LHC Physics program. In general mass reach is increased by ~ 1.5 TeV for Z’, heavy SUSY squarks or gluinos or ~ 20% of extra dimension mass scales. A ~ 20% measurement of the HHH coupling is possible for Higgs masses < 200 GeV. However, to realize these improvements we need to maintain the capabilities of the LHC detectors.

VLHC

LHC

Tevatron


KinematicsKinematics

Heavy States decay at wide angles. For example Z’ of 1 and 5 TeV decaying into light pairs. Therefore, for these states we will concentrate on wide angle detectors.

1 TeV5 TeV

/d dy

barrel y barrel


Detector EnvironmentDetector Environment

LHC SLHC

s 14 TeV 14 TeVL 1034 1035

100 1000

Bunch spacing dt 25 ns 12.5 ns

N( interactions/x-ing) ~ 12 ~ 62 dNch/d per x-ing ~ 75 ~ 375

Tracker occupancy 1 5Pile-up noise 1 ~2.2Dose central region 1 10

Bunch spacing reduced 2x. Interactions/crossing increased 5 x. Pileup noise increased by 2.2x if crossings are time resolvable.

2/( sec)cm 2/( sec)cm 1 /fb yr 1 /fb yr

Ldt


Pileup and LuminosityPileup and LuminosityFor ~ 50 mb, and = 6 charged pions/unit of y with a luminosity

and a crossing time of 12.5 nsec :

In a cone of radius = 0.5 there are ~ 70 pions, or ~ 42 GeV of transverse momentum per crossing. This makes low Et jet triggering and reconstruction difficult.

Ic

35 210 / seccm

95 10 int/ sec

62 int/

375 / ,

x

x ing

x ing unit of y


WW Fusion and “Tag Jets”WW Fusion and “Tag Jets”These jets have

~ pileup R = 0.5 and <y> ~ 3. Lose 5x in fake rejection. We must use the energy flow inside a jet cone to further reduce the fake jets due to pileup (~ uniform in R).

~ / 2T WE M

WW fusion

Pileup, R=0.5, |y|=3


Tracking DetectorsTracking Detectors Clearly, the tracker is crucial for much of the LHC physics [e.g. e, , jets (pileup, E flow), b tags].

The existing trackers will not be capable of utilizing the increased luminosity as they will be near the end of their useful life.

It is necessary to completely rebuild the LHC tracking detectors.


Tracker - OccupancyTracker - OccupancyThe occupancy, O, for a detector of area dA and sensitive time time dt at (r,z) is

e.g. Si strip 10 cm x 100 m in a 12.5 nsec crossing at r = 20 cm is 1.5 %For higher luminosity, decrease dA, or decrease dt (limit is x-ing time) or increase r – smaller, faster or further away.

2( ) /[2 ]I c dAdtO r


Tracker OccupancyTracker OccupancyPreserve the performance using :

Push Si strips out to ~ 60 cm. – developmentPush pixels out to 20 cm. – developmentFor r < 20 cm. Need new technologies – basic research

Shrink dA 5x at fixed r to preserve b tagging? If 12.5 nsec bunch x-ing, need 5x pixel size reduction.Possibilities

3-d detectors – electrodes in bulk columnsDiamond (RD42) - radhardCryogenic (RD39) – fast, radhardMonolithic – reduced source capacity.

21/ r


Tracker ID vs. RadiusTracker ID vs. Radius

100

101

102

103

10-1

100

101

102

103 Ionizing Dose in Tracker for 10 35 L and 1 Year

r(cm)

Dos

e(M

rad)

naive

1 2 3

Define 3 regions. With 10x increase in L, need a ~ 3x change in radius to preserve an existing technology. The ID scales as ~ 2/ r


Electronics – Moore’s LawElectronics – Moore’s LawMicro-electronics: line-widths decrease by a factor 2 every 5 years. DSM (0.25 m) is radiation hard.Today 0.13 m is commercially available. In the lab 0.04 m, e.g. extreme UV lithography, is in existence. Expect trend will continue for a decade.

R&D Characterize emerging technologies

more radiation tolerance required – dose and Single Event Effects

advanced high bandwidth data link technologies

system issues addressed from the start

P. Sharp

Industry

Research

1m

10m

0.1m

20001985


HCAL and ECAL DoseHCAL and ECAL Dose

0 1 2 3 4 510

-2

10-1

100

101

102

103 Dose in ECAL and HCAL for L = 1035 and One Year

Dos

e(M

rad)

The dose ratio is ~ . Barrel doses are not a problem. For the endcaps a technology change may be needed for 2 < |y| < 3 for the CMS HCAL. Switch to quartz as in HF? SD ~ ID/sin.

( ) /th cE p p E

naive

ecal

hcal


HCAL - CoverageHCAL - Coverage

Reduced forward coverage to compensate for 10x L is not too damaging to “tag jet” efficiency, SD ~ 1/3 ~ e3


Scintillator - Dose/DamageScintillator - Dose/Damage

Scintillator under irradiation forms Color centers which reduce the Collected light output (transmission loss). LY ~ exp[-D/Do], Do ~ 4 Mrad

This technology will not survive gracefully at |y| ~ 3. Use the technology that works at LHC up to |y|~ 5, quartz fibers/plates ?

|y|=2, 1 yr.


Muons and ShieldingMuons and ShieldingThere is factor ~ 5 in headroom at design L. With added shielding, dose rates can be kept constant if angular coverage goes from |y|<2.4 to |y|<2.

2/( sec)n cm

r

r

z


Trigger and DAQTrigger and DAQAssuming LHC initial program is successful, raise the trigger thresholds?Rebuild trigger system to run at 80 MHz? Utilize those detectors which are fast enough to give a BCID within 12.5 nsec (e.g. Calorimetry, Tracking, Muon?).Examine algorithms to alleviate degraded e isolation, for example.Design for the increased event size (pileup) with reduced L1 rate and/or data compression.For DAQ track the evolution of communication technologies, e.g. 10 Gb/sec Ethernet.


Level-1 Trigger Table (2x10Level-1 Trigger Table (2x103333))

Trigger Threshold

(GeV)

Rate (kHz) Cumulative Rate (kHz)

Isolated e/ 29 3.3 3.3

Di-e/ 17 1.3 4.3

Isolated muon 14 2.7 7.0

Di-muon 3 0.9 7.9

Single tau-jet 86 2.2 10.1

Di-tau-jet 59 1.0 10.9

1-jet, 3-jet, 4-jet

177, 86, 70 3.0 12.5

Jet*ETmiss 88*46 2.3 14.3

Electron*jet 21*45 0.8 15.1

Min-bias 0.9 16.0

TOTAL 16.0

Steeply falling spectra. Use muons and calor only? Jets and muons ~ clean HLT is resolution on spectral “edge”


Level-1 Trigger Table (10Level-1 Trigger Table (103434))Trigger Threshold

(GeV or GeV/c)

Rate (kHz) Cumulative Rate (kHz)

Isolated e/ 34 6.5 6.5

Di-e/ 19 3.3 9.4

Isolated muon 20 6.2 15.6

Di-muon 5 1.7 17.3

Single tau-jet 101 5.3 22.6

Di-tau-jet 67 3.6 25.0

1-jet, 3-jet, 4-jet 250, 110, 95 3.0 26.7

Jet*ETmiss 113*70 4.5 30.4

Electron*jet 25*52 1.3 31.7

Muon*jet 15*40 0.8 32.5

Min-bias 1.0 33.5

TOTAL 33.5

L1 Trigger on leptons, jets, missing ET and calib/minbias. Does this suite cover all the Physics we want?


L1 at 10L1 at 103535 ? ?Muons are ~ clean. Issue of low momentum muons from b jets. Jets are ~ clean. ECAL jets are mostly “garbage” need tracker to make big L1 improvements.

Rutherford scattering ~ 1/PT

3.

1034 1035

20 40

5 7.5

J 250 540

J*MET 113*70 170*100


Higgs Self Coupling Higgs Self Coupling Baur, Plehn, Rainwater HH W+ W- W+ W- jj jj

Find the Higgs? If the H mass is known, then the SM H potential is completely known HH prediction. If H is found, measure self-couplings, but ultimately SLHC is needed.

CMS will not, in all scenarios, be moving to higher masses. Sometimes rarer processes must be measured at the same mass scale.


HLT Summary: 2x10HLT Summary: 2x103333 cm cm-2-2ss-1-1

Trigger Threshold(GeV or GeV/c)

Rate (Hz) Cuml. rate (Hz)

Inclusive electron 29 33 33

Di-electron 17 1 34

Inclusive photon 80 4 38

Di-photon 40, 25 5 43

Inclusive muon 19 25 68

Di-muon 7 4 72

Inclusive tau-jet 86 3 75

Di-tau-jet 59 1 76

1-jet * ETmiss 180 * 123 5 81

1-jet OR 3-jet OR 4-jet

657, 247, 113 9 89

Electron * jet 19 * 45 2 90

Inclusive b-jet 237 5 95

Calibration etc 10 105

TOTAL 105


HLT Performance HLT Performance — Efficiency— Efficiency

Channel Efficiency

(for fiducial objects)

H(115 GeV) 77%

H(160 GeV)WW* 2 92%

H(150 GeV)ZZ4 98%

A/H(200 GeV)2 45%

SUSY (~0.5 TeV sparticles) ~60%

With RP-violation ~20%

We 67% (||<2.1, 60%)

W 69% (||<2.1, 50%)

tX 72%

Gains in HLT? Tracker (pixel) biggest gain for e. Single muon and electron still the highest rates.


Level-1 TriggerLevel-1 TriggerTrigger Menus

Triggers for very high pT discovery physics: no rate problems – higher pT thresholds Triggers to complete LHC physic program: final states are known – use exclusive menus Control/calibration triggers with low thresholds (e.g. W, Z and top events): prescale

Impact of Reduced Bunch Crossing Period Advantageous to rebuild L1 trigger to work with data sampled at 80 MHz ? Work out the consequencesRequire modifications to L1 trigger and detector electronics Could keep some L1 trigger electronics clocked at 25 ns?

R&D Issues Data movement is probably the biggest issue for processing at 80 MHz sampling Processing at higher frequencies and with higher input/output data rates to the processing elements. Technological advances (e. g. FPGA ) will help Synchronization (TTC) becomes an issue for short x-ing period


HCAL TimingHCAL Timing


SummarySummaryThe LHC Physics reach will be substantially increased by the higher luminosity of the SLHC program.To realize that improvement, the LHC detectors must preserve performance.The trackers must be rebuilt – with new technology at r < 20 cm.The calorimeters, muon systems, triggers and DAQ will need development.The upgrades are likely to take ~ (6-10) years. Accelerator is ready ~ (2012, 2014). The time to start is now.The work on the SLHC for CMS are beginning.

SLHC Trigger Workshop – Feb. 13, 2004 1 Super LHC - SLHC LHC Detector Upgrade Dan Green Fermilab.

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Transcript of SLHC Trigger Workshop – Feb. 13, 2004 1 Super LHC - SLHC LHC Detector Upgrade Dan Green Fermilab.