1. 4-APR-06 CMS SLHC Perugia - Baden 1 Forward Jet Triggering for an Upgraded CMS Drew Baden - University of Maryland Jeremy Mans - University of Minnesota Chris Tully - Princeton University

2. 4-APR-06 CMS SLHC Perugia - Baden 2 HF Basics HF covers ~3<  <5 located at ±11.1m from IP Steel absorber and rad hard quartz fibers –Cerenkov light collected via phototubes, uniform HCAL readout 36  and 12  = 432 towers per side –  =10° and  =0.166 Each tower has long and short fibers running along z –Short (S) is in the back ~ “ET HAD ” –Long (L) is front to back ~ “ET EM+HAD ” –Readout after ganging all S and all L –Makes 2x432=864 towers per side HF

3. 4-APR-06 CMS SLHC Perugia - Baden 3 Jets in Level 1 TPGs –HB/HE: 0.087x0.087  x  0.5 x 0.35 in HF CMS Level 1 Jets –Calorimeter organized into “Regions” 4x4 TPGs per region in HB and HE, formed by RCT 1 TPG per region in HF, formed by HCAL HTRs and transmitted thru RCT –Regions are sent GCT for jet finding Jet finding via “sliding window” Sliding window using 3x3 regions Calorimeter “Region” Barrel/Endcap TPG (  x  ) Region HB/HE0.087x0.0874x4 TPGs HF0.5 x 0.351 TPG

4. 4-APR-06 CMS SLHC Perugia - Baden 4 CMS Calorimeter Segmentation Tower #  TPG (  x  ) Calorimeter RCT Regions 1-4 0.087 0.87 x 0.87 1: 0.000 <  < 0.348 -  0.348  0.348 HB 5-8 2: 0.348 <  < 0.695 -  0.348  0.348 9-12 3: 0.695 <  < 1.044 -  0.348  0.348 13-15 4: 1.044 <  < 1.392 -  0.348  0.348 16HB/HE overlap 17-200.087 0.87 x 0.87 5: 1.392 <  < 1.740 -  0.348  0.348 HE 210.09 0.174 0.090 x 0.087 6: 1.740 <  < 2.172 -  0.432  0.348 HE, split into 2 equal half energies in  220.100.100 x 0.087 230.1130.113 x 0.087 240.1290.129 x 0.087 250.15 0.174 0.150 x 0.087 7: 2.172 <  < 3.000 -  0.828  0.348 260.1780.178 x 0.087 270.150.150 x 0.087 280.350.350 x 0.087 29-31 0.1670.1740.348 x 0.5 8: 3.000 <  < 3.500 -  0.5  0.348 HF 32-34 9: 3.000 <  < 3.500 -  0.5  0.348 25-37 10: 3.000 <  < 3.500 -  0.5  0.348 38-40 11: 3.000 <  < 3.500 -  0.5  0.348

5. 4-APR-06 CMS SLHC Perugia - Baden 5 Min Bias Atlas CERN/LHC 96-40 Min bias distributions @ 10 34 – ~20 (assumes ~80mb inelastic) – ~ ~ 8 @ 14TeV – ~ few GeV (and falls exponentially) –20 x 8 ch x 10 d  x 2GeV = 3.2 TeV/interaction (Had) –HF...40% of CMS in  coverage 640 GeV, 72 TPGs/side, ~10 GeV/TPG (@ =20) –Current TPG = 0.5 x 0.348  x  SLHC upgrade –Increase E T /TPG from minbias scales with increase in –Clearly, the only way to keep up without ramping thresholds up is to look at TPGs on finer scale New Level 1 triggering will need to… –Sharpen efficiency –Move HLT-like algorithms and resolution as close to L1 as possible

6. 4-APR-06 CMS SLHC Perugia - Baden 6 SLHC Background Reduction Beat down the background L1A rate –LHC Design luminosity of 10 34 has large backgrounds: –Depending on the scheme for high luminosity ~ current for 25ns SLHC, rates scale with Luminosity for continuous beam….smaller but large pileup...not sure –100kHz L1A rate is ingrained, will most likely hold Size of derandomizing buffers, etc. Bandwidth to HLT Number of HLT processors.... CMS Calorimeter trigger based on TPGs –In HF… 1 TPG = 6 towers (3  x 2  ) Lack of granularity might make it useless for Level 1 jet triggers with large number of multiple interactions without drastic threshold increases –In HB and HE… Jet-finding in Level 1, saturation effect due to pileup at high luminosity  trigger (requires most energy to be in 1 region) difficultie at high pileups Ditto for isolated e and  triggers ConditionProcessRate 1  E T >60Jet  0   10Hz 2  E T >15Jets   0 s  10Hz 1 l p T >60W  l, jet  l 10Hz 2 l p T >15Z  l l 20Hz ET miss > 150QCD jets10Hz

7. 4-APR-06 CMS SLHC Perugia - Baden 7 SLHC Signal Enhancement Add functionality –W Boson Fusion (WBF) dominant experimentally accessible rate Forward jets + central Higgs decay Tag jets are in HF+HE so HE will need to be included –Higgs id without a tag is very hard Gluon fusion backgrounds are too high, esp at 10 35 –Current trigger at high luminosity will be difficult Depends on scheme for increasing luminosity of course… C. Tully & H. Pi JetMetPRS Aug 2004  (tagged “forward” jets)

8. 4-APR-06 CMS SLHC Perugia - Baden 8 Forward Jets in Level 1 Jeremy Mans, Chris Tully, monte carlo simulations using ORCA Try to optimize forward jet trigger to keep the thresholds on central objects from increasing due to pileup at high luminosity –Plot of forward jet trigger rate shows huge effect at low E T –Pileup effects at ~10 34 will cause thresholds of ~50-60 GeV to get away from pileup dominating real jets Signal is reduced to almost nothing NB: this does not take into account central object trigger…so it’s not as bad as that but it’s still a big loss due to pileup

9. 4-APR-06 CMS SLHC Perugia - Baden 9 Jet Shape and Pileup Diagram for WBF has no “color string” across the detector QCD forward jets will be much more “active” This can be seen in the jet shape (2 nd moment) –Energy is from pileup is added to jet far from core –Easier to deal with using smaller regions

10. 4-APR-06 CMS SLHC Perugia - Baden 10 Another Look at Shapes… Current scheme –Jet candidates using 3x3 CR sum,  x  =1.5 x 1.0 –Slides window by 1 CR,  x  =0.5 x 0.35 New scheme –Construct jet candidates from 4x4 tower sums,  x  =0.67 x 0.7 –Slide window by 1 tower,  x  =0.17 x 0.17 Feature bit on if number of cells needed to sum 60% of E T (n60) in 4x4 cluster < cut –Use n60 < 7 to set feature bit –Prelim studies show QCD jets are narrow & well contained Jets from.5 cone all have 2 nd moment < 0.3 in R Require jet candidate threshold && feature bit = 1 Can also require perimeter “quiet” for isolation –Not studied yet…

11. 4-APR-06 CMS SLHC Perugia - Baden 11 Hardware Design We propose NOT changing current HTR –48 QIE channels input –6 SLB sites Each SLB transmits 2 TPGs/link over 4 links/cable –For HF, 1TPG = 6 QIE channels 48/6 = 8 TPG output HF HTRs will only populate 1 SLB site We will have 5 free SLB sites to use 12.5n s Proposal: –Luminosity: dedicate 1 SLB site –Jet trigger: dedicate 3 SLB sites Means running L and S fibers @ 80MHz, or L+S after summing @ 40MHz –Send data to…TBD…during CMS running parasitically…study study study

12. 4-APR-06 CMS SLHC Perugia - Baden 12 HF Forward Jet Study Elecctronics HF Transmitter (HFT) –3-SLB-site mezzanine card on HTRs –Transmits raw HF towers for clustering investigations –Optical transmitters, 1.6Gbps 8B/10B using 12-way MTP connectors (18 per side) –Already being laid out – expect to have something available for studies at H2 summer 06 HF Jet Processor (HFJ) –Jeremy Mans/UMN –Receives fiber data and processes into jets… –New GCT Leaf/Wheel cards might be ideal for rapid development for studies HTR HFT SLB HLX RCT Luminosity “consumers” HFJ 2 HTRs = 4(  ) x 12(  ) 18 HTRs per + and – side of CMS

13. 4-APR-06 CMS SLHC Perugia - Baden 13 Rack Topology Chris Tully worked this out with Rohlf and Ianos Schmidt, ok’d by Wesley Smith New “Luminosity” VME crate in the center minimizes distance from the 3 HF crates and doesn’t break topology for Level 1 –Can put any electronics developed for HF forward jet trigger studies here

14. 4-APR-06 CMS SLHC Perugia - Baden 14 R&D Program Scrub design so that we can piggyback on existing system and build cards that can be implemented by LHC startup –Keep entire current VME architecture, but add new capability –Run parasitically, collect data, study, iterate R&D list for Trigger project –Much simulation needed to settle on algorithm approach –HLT card: Learn how to use new FPGA’s with embedded processing, DSP, built-in deserializers…. Continue to verify HTR to HLT @ 80MHz –HLT to HJF transmission Implement transmitting signals over MTP fiber ribbons @ 1.6Gbps using Rocket IO Use crystals to drive transmitter as an alternate scheme (asynchronous fifo’s on both ends) –HFJ Study algorithms for clustering – lots of simulation needed here Build new types of 9U boards or follow GCT project?