SLHC EMU Simulations

1. SLHC EMU Simulations • Vadim Khotilovich, Alexei SafonovTexas A&M University CMS Week, CSC Upgrade Session – March 16, 2008

2. Goals Of Muon SLHC Simulations Group • Ultimate goals: • Implement simulation framework that would quantitatively describe future CMS detector and trigger in the SLHC luminosity environment • Provide basis and tuning for hardware upgrade • Progress will be iterative with simulations and detector people findings feeding into each other • Started a joined simulation effort with Barrel, part of the CMS-wide upgrade simulation task force CMS Week, CSC Upgrade Session

3. Facing Problems • Substantial increase in occupancies • Only 2 stubs/chamber or 2-3 per/sector delivered by local trigger might be not enough • High chances of signal muon stub to be missed • Stations closest to the interaction point are especially affected • These stations are crucial for trigger tracking • Track Finder would not reconstruct momentum properly when crucial stubs are missed or wrong ones are picked up • Need to suppress higher trigger rates • Need to preserve high efficiency • Changing simulation framework to reflect planned hardware upgrades and to provide reliable predictions • Coping with high pileup in full simulation • Addition of ME4/2 • Upgrade of ME1/1 with addition of fully functional ME1/A • Adding matching of TF tracks to new tracking trigger • Tuning of emulator algorithms • Basis for firmware updates CMS Week, CSC Upgrade Session

4. Signal: Pile-Up Events: Initial Sample Event Generator FilterModule FilterModule Stripped Sample Standard MixingModule Digi Simulation L1 Emulation Some Reco Full Simulation with Pileup • Understanding occupancy related effects and non-muon (neutron) backgrounds make Full Geant simulation a far preferred option • Implementation of High PU environment is difficult due to high memory consumption • Custom solution that we developed: • Full simulation in a fraction of the detector with all bells and whistles • Including out of time pile-up • Drop unnecessary information, trigger and reconstruction components to minimize memory problems and event size • Ported from 16X to 22X CMS Week, CSC Upgrade Session

5. Choice of Base CMSSW Release • Needrelatively stable and mature release in order to be able to focus more on issues  that are important for SLHC • 31X is tempting: • New and better organized DB infrastructure • No need to back-port new developments • More memory efficient pileup machinery will be available • ME42 will be by default in • People really want to “get it right” • However: • It would take more than a month to get it relatively stable • MixingModule and new CrossingFrame are still in development there • Crucial for high pileup simulations • So far sticking with 22X • 226 to be more exact, as earlier will be obsolete soon • Harder to cope with DB issues CMS Week, CSC Upgrade Session

6. Addition of ME4/2 • Required modified geometry and conditions DB • Will be default in 31X • Took a considerable amount of time to debug problems that were arising when we enabled ME4/2 • Complex handling of conditions DB was picking tables with bad chambers masking • Noise matrix values were stored in order not expected by offline • leading to unexpected randomness and memory overlaps • It was rather hard to trace • Thanks to Rick Wilkinson, Tim Cox, Oana Boeriu and Slava Valuev! • Functional now in 226! • Updated instruction are at twiki https://twiki.cern.ch/twiki/bin/view/CMS/SLHCMuonTriggerSimulations CMS Week, CSC Upgrade Session

7. New Samples • Di-muon particle gun • 10<PT<100 • 0.8<eta<2.5 for CSC studies • eta>20 for rate studies • Puileup is added: PU0, 25, 200, 400 • Only muon SimHits are mixed in eta>0 (no SimTracks) • 20-30K events • ME42 included • TrackFinder updated to take advantage of it (nextg slide) • Plan • Make similar samples for DT • Make sure that everyone interested can access the samples CMS Week, CSC Upgrade Session

8. Track Finder adaptation for ME42 • TF efficiency vs eta for various TF track qualities • Before • Q3 tracks had big gaps in midrange eta b/c TF lookup tables did not connect properly ME4/2 and • New fix to TF code (from Joe Gartner and Darin Acosta) • allows to get rid of those gaps CMS Week, CSC Upgrade Session

9. Efficiency step-by step in PU400 • Efficiencies at different L1 stages vs eta • Quite high for all TF PT and all BX’s • ME4/2 makes this dip much smaller • As soon as we apply PT(TF)>10 GeV TF efficiency drops in ring 1 region CMS Week, CSC Upgrade Session

10. Analyzing ME1 and BX Influence • Having stub in ME1 is very important for TF to determine PT • No PT cut but at least one matching stab in ME1 • TF eff still drops in ring 1 (dashed line) • But there are stubs in ME11! (green line) • Requiring central BX • BXALCT=0, BXCLCT=0,±1 • This isolates the problem! • We are loosing “good” stubs and picking “bad” ones CMS Week, CSC Upgrade Session

11. BX Comparison for PU400 and PU0 • Closer look at Local TP BX • min|BX| of LTP in chamber that has track’s SimHIts • Normalized by number of chambers with track’s SH • PU400 (solid) and PU0 (dashed) • Comparing ME1/1 (left) to ME1/1 (right) • BX in ME1/2 look very similar for PU400 and PU0 • General trend for R1 stations • Mostly not picking “good” CLCT in ME11 leads to decrease of “good” stubs CMS Week, CSC Upgrade Session

12. Local Trigger Primitives Occupancy • Local TP occupancies in half-detector (no BX req) • Requiring central BX (big help in BG reduction) CMS Week, CSC Upgrade Session

13. Conclusion and Near Plans • … CMS Week, CSC Upgrade Session