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

2. SLHC Trigger Workshop – Feb. 13, 2004 2 Outline Physics Basics Z’ vs Rapidity Range Minbias Pileup and Jets Occupancy and Radiation Dose Tracker Upgrade Calorimetry Muons Trigger and DAQ CERN-TH/2002-078 “Physics Potential and Experimental Challenges of the LHC Luminosity Upgrade” [10x will be challenging]

3. SLHC Trigger Workshop – Feb. 13, 2004 3 Mass Reach vs L 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

4. SLHC Trigger Workshop – Feb. 13, 2004 4 Kinematics 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 TeV 5 TeV barrel y barrel

5. SLHC Trigger Workshop – Feb. 13, 2004 5 Detector Environment LHC SLHC  s 14 TeV 14 TeV L 10 34 10 35 100 1000 Bunch spacing dt 25 ns 12.5 ns N( interactions/x-ing) ~ 12 ~ 62 dN ch /d  per x-ing ~ 75 ~ 375 Tracker occupancy 1 5 Pile-up noise 1 ~2.2 Dose central region 1 10 Bunch spacing reduced 2x. Interactions/crossing increased 5 x. Pileup noise increased by 2.2x if crossings are time resolvable.

6. SLHC Trigger Workshop – Feb. 13, 2004 6 Pileup and Luminosity For ~ 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 E t jet triggering and reconstruction difficult.

7. SLHC Trigger Workshop – Feb. 13, 2004 7 WW Fusion and “Tag Jets” These jets have ~ pileup R = 0.5 and ~ 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). WW fusion Pileup, R=0.5, |y|=3

8. SLHC Trigger Workshop – Feb. 13, 2004 8 Tracking 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.

9. SLHC Trigger Workshop – Feb. 13, 2004 9 Tracker - Occupancy The 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.

10. SLHC Trigger Workshop – Feb. 13, 2004 10 Tracker Occupancy Preserve the performance using : Push Si strips out to ~ 60 cm. – development Push pixels out to 20 cm. – development For 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 columns Diamond (RD42) - radhard Cryogenic (RD39) – fast, radhard Monolithic – reduced source capacity.

11. SLHC Trigger Workshop – Feb. 13, 2004 11 Tracker ID vs. Radius naive 123 Define 3 regions. With 10x increase in L, need a ~ 3x change in radius to preserve an existing technology. The ID scales as ~

12. SLHC Trigger Workshop – Feb. 13, 2004 12 Electronics – Moore’s Law Micro-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 1m1m 10  m 0.1  m 20001985

13. SLHC Trigger Workshop – Feb. 13, 2004 13 HCAL and ECAL Dose 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 . naive ecal hcal

14. SLHC Trigger Workshop – Feb. 13, 2004 14 HCAL - Coverage Reduced forward coverage to compensate for 10x L is not too damaging to “tag jet” efficiency, SD ~ 1/  3 ~ e 3 

15. SLHC Trigger Workshop – Feb. 13, 2004 15 Scintillator - Dose/Damage 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.

16. SLHC Trigger Workshop – Feb. 13, 2004 16 Muons and Shielding There 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. r r z

17. SLHC Trigger Workshop – Feb. 13, 2004 17 Trigger and DAQ Assuming 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.

18. SLHC Trigger Workshop – Feb. 13, 2004 18 Level-1 Trigger Table (2x10 33 ) TriggerThreshold (GeV) Rate (kHz)Cumulative Rate (kHz) Isolated e/  293.3 Di-e/  171.34.3 Isolated muon142.77.0 Di-muon30.97.9 Single tau-jet862.210.1 Di-tau-jet591.010.9 1-jet, 3-jet, 4- jet 177, 86, 703.012.5 Jet*E T miss 88*462.314.3 Electron*jet21*450.815.1 Min-bias0.916.0 TOTAL16.0 Steeply falling spectra. Use muons and calor only? Jets and muons ~ clean  HLT is resolution on spectral “edge”

19. SLHC Trigger Workshop – Feb. 13, 2004 19 Level-1 Trigger Table (10 34 ) TriggerThreshold (GeV or GeV/c) Rate (kHz)Cumulative Rate (kHz) Isolated e/  346.5 Di-e/  193.39.4 Isolated muon206.215.6 Di-muon51.717.3 Single tau-jet1015.322.6 Di-tau-jet673.625.0 1-jet, 3-jet, 4-jet250, 110, 953.026.7 Jet*E T miss 113*704.530.4 Electron*jet25*521.331.7 Muon*jet15*400.832.5 Min-bias1.033.5 TOTAL33.5 L1 Trigger on leptons, jets, missing E T and calib/minbias. Does this suite cover all the Physics we want?

20. SLHC Trigger Workshop – Feb. 13, 2004 20 L1 at 10 35 ? 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/P T 3. 10 34 10 35  2040    57.5 J250540 J*MET113*70170*100

21. SLHC Trigger Workshop – Feb. 13, 2004 21 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.

22. SLHC Trigger Workshop – Feb. 13, 2004 22 HLT Summary: 2x10 33 cm -2 s -1 TriggerThreshold (GeV or GeV/c) Rate (Hz)Cuml. rate (Hz) Inclusive electron2933 Di-electron17134 Inclusive photon80438 Di-photon40, 25543 Inclusive muon192568 Di-muon7472 Inclusive tau-jet86375 Di-tau-jet59176 1-jet * E T miss 180 * 123581 1-jet OR 3-jet OR 4- jet 657, 247, 113989 Electron * jet19 * 45290 Inclusive b-jet237595 Calibration etc10105 TOTAL105

23. SLHC Trigger Workshop – Feb. 13, 2004 23 HLT Performance — Efficiency ChannelEfficiency (for fiducial objects) H(115 GeV)  77% H(160 GeV)  WW*  2  92% H(150 GeV)  ZZ  4  98% A/H(200 GeV)  2  45% SUSY (~0.5 TeV sparticles)~60% With R P -violation~20% W  e 67% (|  |<2.1, 60%) WW 69% (|  |<2.1, 50%) t  X 72% Gains in HLT? Tracker (pixel) biggest gain for e. Single muon and electron still the highest rates.

24. SLHC Trigger Workshop – Feb. 13, 2004 24 Level-1 Trigger Trigger Menus Triggers for very high p T discovery physics: no rate problems – higher p T 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 consequences Require 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

25. SLHC Trigger Workshop – Feb. 13, 2004 25 HCAL Timing

26. SLHC Trigger Workshop – Feb. 13, 2004 26 Summary The 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.