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Performance and physics results for Phase1 upgrade

Performance and physics results for Phase1 upgrade

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Performance and physics results for Phase1 upgrade

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  1. Performance and physics results for Phase1 upgrade Alessia Tricomi (University and INFN Catania) on behalf of the Tracker Upgrade Simulation Group

  2. Performance studies • The goal for the TDR wasto show improvement in Physics cases and robustness of the new design. • Focus on relative improvement of the upgrade wrt current geometry. • Two complementary approaches: • Show improvements in basic building blocks for physics using a full (Geant) simulation of the upgrade • Demonstrate improvements in tracking efficiency and fake rate • Demonstrate improved IP resolution and b-tagging performance • Improvements in relevant physics channels (under PC responsibility) Pixel Upgrade Meeting Alessia Tricomi

  3. Pixel Upgrade dictionary • Current Detector: • Current pixel detector geometry (3 barrel layers, 2 disks) • Current beam pipe • Dedicated “SLHC” release CMSSW_4_2_8_SLHC2 to use Design/Ideal conditions and same configurations/settings for tracking • Phase1 Upgrade (R30F12) geometry: • Upgrade geometry with 4 BPIX layers and 3 endcapdisks • First barrel layer at R=30 with 12 faces • New detailed material description according to PSI drawings • New beampipe (Sunanda) implemented • CMSSW_4_2_8_SLHCtk + 520 backporting Pixel Upgrade Meeting Alessia Tricomi

  4. Upgrade Studies • Study at • 2×1034 cm-2s-1 at 25ns (50ns),<PU>=50 (100) • 1×1034 cm-2s-1 at 25 ns,<PU>=25 • zero PU • Dynamic data loss (due to pixel ROC) used in simulations • Tracking steps modified for upgrade geometry and high PU • Using CMSSW_4_2_8 but with 5_2_0 tracking backported • Dropped detached tracking steps (see backup slides) • Used regular CMS DQM validation packages to get tracking and b-tagging performance plots • Fullsim, 14 TeV, ideal conditions, no pixel CPE templates used • ttbar from PYTHIA (10K events) • Muon gun (10K events-4 muons/event, generated flat in pT and eta, 200k events-ten muons/event, generated flat in p and eta) Pixel Upgrade Meeting Alessia Tricomi

  5. Data loss for Upgrade Studies • Peak luminosity values Pixel Upgrade Meeting Alessia Tricomi

  6. Upgrade Iterative Tracking (Stdgeom) • 5_2_0 tracking for current pixel geometry (from “2012 tune”) • Close to 5_2_0 tracking, use steps 0-2, and 4A (for high eta) • Reduce step 4A d0 cut to reduce CPU and memory usage Release CMSSW_4_2_8_SLHCstd2_patch1 Tracking steps Pixel Upgrade Meeting Alessia Tricomi

  7. Upgrade Iterative Tracking (Phase 1) • 5_2_0 tracking for Phase 1 geometry (not optimized) • Make close to 5_2_0 tracking, use steps 0-2, and 4A, add step “-1” • Step 3 (pixel pairs) to recover efficiency in eta ~1.2–1.4 region Release CMSSW_4_2_8_SLHCtk3_patch1 Tracking steps Pixel Upgrade Meeting Alessia Tricomi

  8. Reduced material even with more layers Pixel Upgrade Material Budget 50% less photon conversion in/before pixel at eta 1.5 Rad. Len. Nucl. Int. Len. Pixels Pixels Dots – Upgrade Green – Currgeom Pixel Upgrade Meeting Alessia Tricomi

  9. Object performance Transverse and Longitudinal IP Primary Vertex Tracking Btagging Robustness Pixel Upgrade Meeting Alessia Tricomi

  10. Impact Parameter Resolutions • Transverse: muon sample (10 muons/event), zero pileup • Generated flat in E and eta (plot vs absolute p and in 4 eta regions) • Compare current and upgrade detectors (modified MTV) Pixel Upgrade Meeting Alessia Tricomi

  11. Impact Parameter Resolutions • Longitudinal: muon sample (10 muons/event), zero pileup • Generated flat in E and eta (plot vs absolute p and in 4 eta regions) • Compare current and upgrade detectors Pixel Upgrade Meeting Alessia Tricomi

  12. Impact Parameter Resolutions • Transverse: muon sample (10 muons/event), <PU>=50 • Generated flat in E and eta (plot vs absolute p and in 4 eta regions) • Compare current and upgrade detectors Pixel Upgrade Meeting Alessia Tricomi

  13. Impact Parameter Resolutions • Longitudinal: muon sample (10 muons/event), <PU>=50 • Generated flat in E and eta (plot vs absolute p and in 4 eta regions) • Compare current and upgrade detectors Pixel Upgrade Meeting Alessia Tricomi

  14. Primary Vertex Resolution • ttbar sample, zero PU and <PU>=50 Pixel Upgrade Meeting Alessia Tricomi

  15. Tracking in ttbar ttbar sample, High purity pT> 0.9 GeV/c Pixel Upgrade Meeting Alessia Tricomi

  16. Tracking with muons • Muonsample • High purity • pT>1 GeV/c • numtracking layers with hits >= 8 Pixel Upgrade Meeting Alessia Tricomi

  17. Tracking Efficiency/Fake Rate • ttbar sample, compare current and upgrade detectors • High purity, pT > 0.9 GeV/c Pixel Upgrade Meeting Alessia Tricomi

  18. Tracking vs PU • Average tracking efficiencies vs PU • ttbar, high purity tracks, pT > 0.9 GeV/c Pixel Upgrade Meeting Alessia Tricomi

  19. Tracking vs PU • Average track fake rates vs PU • ttbar, high purity tracks, pT > 0.9 GeV/c Pixel Upgrade Meeting Alessia Tricomi

  20. B-tagging Performance • ttbar, CSV tagger, compare current and upgrade • ak5PFjets PFnoPU, jet pT > 30 GeV, DUS ,c,b jets 15% absolute gain in b jet efficiency for 1% fake rate Pixel Upgrade Meeting Alessia Tricomi

  21. B-tagging Performance • ttbar, CSV tagger, compare current and upgrade, <PU>=100 • ak5PFjets PFnoPU, jet pT > 30 GeV, DUS ,c,bjets Improvement even more impressive at 100 PU Pixel Upgrade Meeting Alessia Tricomi

  22. B tagging performance • Upgrade as good or better at high pileup as current at low pileup Upgrade PU50 Current PU0 Upgrade PU50 Current PU25 Pixel Upgrade Meeting Alessia Tricomi

  23. B-tagging Performance vs PU • ttbar, CSV tagger, compare current and upgrade, <PU>=50 • ak5PFjets PFnoPU, jet pT > 30 GeV, DUS,b jets • Much better handling high Pile-Up Pixel Upgrade Meeting Alessia Tricomi

  24. Robustness: BPIX1 Inefficiency Study • Vary inefficiency of BPIX layer 1: 0%, 5%, 10%, 20% • All other layers at 100% • ttbar, <PU>=50, light quark mis-tag=1% • Upgrade detector more robust to BPIX1 inefficiency Pixel Upgrade Meeting Alessia Tricomi

  25. Robustness: BPIX1 Inefficiency Study • Vary inefficiency of BPIX layer 1: 0%, 5%, 10%, 20% • All other layers at 100% • ttbar, <PU>=50, high purity tracks, pT>0.9 GeV/c • Upgrade detector more robust to BPIX1 inefficiency Pixel Upgrade Meeting Alessia Tricomi

  26. TIB Inefficiency Study • Switch off certain modules (in black below) • List provided by Frank Hartmann • Or consider a uniform 20% inefficiency in TIB1,2 Pixel Upgrade Meeting Alessia Tricomi

  27. Robustness to TIB degradation With Dead Modules Upgrade detector more robust wrt TIB loss With 20% uniform inefficiency in TIB1,2 Pixel Upgrade Meeting Alessia Tricomi

  28. Small pixel scenario: tracking with ttbar at 100PU BPIX Layer1: pixel size 75x100 mm2, 220 mm thickness ROC threshold 1200 e- instead of 2000 Significant improvement at 100 PU wrt Upgrade Phase1 detector Good news towards Phase2 Pixel Upgrade Meeting Alessia Tricomi

  29. Small pixel scenario: btagging performance BPIX Layer1: pixel size 75x100 mm2, 220 mm thickness ROC threshold 1200 e- instead of 2000 No data loss Significant improvement at 100 PU wrt Upgrade Phase1 detector Good news towards Phase2 Pixel Upgrade Meeting Alessia Tricomi

  30. Physics Performance ZHllbb HZZ4l SUSY MT2 SUSY gg+MET All analysis show relative improvement and have not been optimized/retuned for high PU Pixel Upgrade Meeting Alessia Tricomi

  31. ZHllbb • Analysis based on: • triggering on lepton events; • kinematic reconstruction of Z from isolated dileptons; • reconstructing invariant mass from two b-tagged jets; • multivariate final variable • Higher muon/electron ID efficiency helps with (1-2), better b-tagging helps with (3-4) • Compare relative performance of current detector and upgrade at 14 TeV with 50 pileup events Pixel Upgrade Meeting Alessia Tricomi

  32. ZHmmbb event selection Pixel Upgrade Meeting Alessia Tricomi

  33. ZHmmbb cut flow Values greater than 1 show increased efficiency for the Phase1 upgrade and vice versa Pixel Upgrade Meeting Alessia Tricomi

  34. ZHeebb event selection • Same selection as for muons but • Electrons use 95% working-point of VBTF • Isolation is relaxed as in the di-muonanalysis • Dimuon mass ~2 GeV high, so Z mass cut increased by +2 GeV like in dimuonanalysis • Other criteria same as for di-muon channel Pixel Upgrade Meeting Alessia Tricomi

  35. ZHeebb cut flow Values greater than 1 show increased efficiency for the Phase1 upgrade and vice versa Pixel Upgrade Meeting Alessia Tricomi

  36. ZHllbb results • ZHmmbb • 65% relative gain in signal efficiency for di-muon channel • 75% gain with single muonHLT • 175% gain with dimuonHLT (upgrade detector barely affected by the three pixel hit requirement) • ZHeebb • 65% relative gain in signal efficiency for di-electron channel • Not enough MC to properly estimate total reductions in backgrounds Pixel Upgrade Meeting Alessia Tricomi

  37. HZZ4l • Analysis based on: • triggering on di-lepton events; • kinematic reconstruction of 2 Zs from isolated di-leptons; • reconstructing invariant mass of Higgs • Higher muon/electron ID efficiency helps with (1-2) • Compare relative performance of current detector and upgrade at 14 TeV with 50 pileup events Pixel Upgrade Meeting Alessia Tricomi

  38. HZZ4l event selection • Using same cuts as in 2012 analysis (HIG-12-016) • PF leptons used • ElectronspT> 7 GeV, |η|<2.5; MuonspT > 5 GeV, |η| < 2.4 • Isolationrelaxedfrom 0.15 to 5.0 • |SIP3D|<4 for each lepton • 40 < mZ1<120 GeV; 12 < mZ2<120 GeV; ml+l->4GeV • m4l> 100 GeV • same HLT estimate as in ZH: 3+ pixel hits on trigger leptons Pixel Upgrade Meeting Alessia Tricomi

  39. HZZ4m cut flow 40% gain in 4m channel Values greater than 1 show increased efficiency for the Phase1 upgrade and vice versa Pixel Upgrade Meeting Alessia Tricomi

  40. HZZ4e cut flow 50% gain in 4e channel Values greater than 1 show increased efficiency for the Phase1 upgrade and vice versa Pixel Upgrade Meeting Alessia Tricomi

  41. HZZ2e2m cut flow 48% gain in 2e2m channel Values greater than 1 show increased efficiency for the Phase1 upgrade and vice versa Pixel Upgrade Meeting Alessia Tricomi

  42. SUSY MT2b analysis • Fully hadronic final states with large MET • B jets coming from cascade decay of gluino and squark to third generation sbottom, stop • SUSY particles identified through the discovery parameter MT2 • Tail of Supersimmetric Transverse Mass related to parent sparticle mass (endpoint) • Compare relative performance of current detector and upgrade at 14 TeV with 50 pileup events wrt to btagging improvement • Signal: LM9 benchmark point • Bkg: ttbar • See AN-2012/275 for details Pixel Upgrade Meeting Alessia Tricomi

  43. SUSY MT2b event selection • Good primary vertes • Veto electrons: pT>10 GeV/c; |η|<2.4; |d0|<0.04cm; |dz|<1.0cm; missing innerhits<2; PFIso<2.0 • Veto muons: pT>10 GeV/c; |η|<2.4; |d0|<0.04cm; |dz|<1.0cm; Trkhits>10; Pixhits>0; PFIso<2.0 • Jets: 2 PF jets with pT> 20 GeV/c passinglooseJetID; veto events with jets pT>50 GeV/c but failing jet ID • MET: PFMET>30GeV;PFH >750GeV • B-tag: Tight CSV tag > 0.898 Pixel Upgrade Meeting Alessia Tricomi

  44. SUSY MT2b analysis Before any b-tagging One b-jet required 20% higher signal selection efficiency can be obtained without any real optimization for the new detector and high pile-up. Pixel Upgrade Meeting Alessia Tricomi

  45. SUSY gg+MET analysis • Di-photon events+MET signature for SUSY • No significant SM bkg, small contribution from Vgg • Main bkg comes from fake MET • See AN-2012/269 • Same 14 TeV, 50 pileup scenario as others • Main improvement comes from fake rate reduction Pixel Upgrade Meeting Alessia Tricomi

  46. SUSY gg+MET analysis • Events divided in four classes: gg, ge, ee, fake-fake • ge and ee samples used to estimate fake rate by fitting Z peak Pixel Upgrade Meeting Alessia Tricomi

  47. SUSY gg+MET analysis • Fake rate 7.0% for the current detector and 1.25% for Phase1 pixel detectors • Fake rate with the upgrade detector at 50 PU is comparable with the performance of the current detector in low luminosity run Pixel Upgrade Meeting Alessia Tricomi

  48. Conclusions • All results show that the new detector at high PU performs as well or even better than the current detector at low luminosity • The results also show that the new detector is fairly robust against possible inefficiency in BPIX1 and TIB1,2 • All the results have been approved by Tracking/btagging/Physics group – PAS SUS-12-020 • Improvements from the new design are broad and substantial and will have a significant impact our physics program • Still a lot of work to be done to tune algorithms and analysis for high PU scenario • Stay tuned! Pixel Upgrade Meeting Alessia Tricomi

  49. Back-up slides Pixel Upgrade Meeting Alessia Tricomi

  50. Tracking for Upgrade Studies • Use 4_2_8 but with 5_2_0 tracking, and drop detached trks • Fullsim, 14 TeV, ideal conditions, no pixel templates • Regular CMS validation package, current and upgrade pixel det Regular 5_2_0 Tracking steps Pixel Upgrade Meeting Alessia Tricomi