Pixel Upgrade Workshop Grindelwald, August 29 th 2012 PERFORMANCE AND PHYSICS RESULTS FOR PHASE1 UPGRADE Alessia Tricomi (University and INFN Catania) on behalf of the Tracker Upgrade Simulation Group
Performance studies The goal for the TDR was to 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) Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 2
Pixel Upgrade dictionary Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 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 endcap disks 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 backporting 3
Upgrade Studies Study at 2×10 34 cm -2 s -1 at 25ns (50ns), =50 (100) 1×10 34 cm -2 s -1 at 25 ns, =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) Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 4
Data loss for Upgrade Studies Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi Peak luminosity values Current DetectorRadius (cm) % Data loss at 1 10 % Data loss at 2 10 % Data loss at 2 10 BPIX BPIX BPIX FPIX1& Phase 1 DetectorRadius (cm) % Data loss at 1 10 % Data loss at 2 10 % Data loss at 2 10 BPIX BPIX BPIX BPIX FPIX
Upgrade Iterative Tracking (Stdgeom) Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 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 d 0 cut to reduce CPU and memory usage IterationSeedsp T cut (GeV) d 0 cut (cm) d z cut (cm) Min hits 0pixel triplets σ bs 3 1low p T pixel triplets σ bs 3 2pixel pairs with vtx σ bs 3 3 detached triplets Apixel +(TEC(1 ring)) triplets BBPIX+TIB triplets TIB, TID, TEC pairs (fewer) TOB, TEC pairs Release CMSSW_4_2_8_SLHCstd2_patch1 Tracking steps 6
Upgrade Iterative Tracking (Phase 1) Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 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 IterationSeedsp T cut (GeV) d 0 cut (cm) d z cut (cm) Min hits 0pixel quadruplets σ bs 3 1pixel triplets σ bs 3 2low p T pixel triplets σ bs 3 3pixel pairs with vtx σ bs 3 3old detached triplets Apixel +(TEC(1 ring)) triplets BBPIX+TIB triplets TIB, TID, TEC pairs (fewer) TOB, TEC pairs Release CMSSW_4_2_8_SLHCtk3_patch1 Tracking steps 7
Pixel Upgrade Material Budget Reduced material even with more layers “Volumes”Mass (g) CurrentDesign Upgrade BPIX < FPIX < Rad. Len.Nucl. Int. Len. Dots – Upgrade Green – Curr geom Pixels Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 8 50% less photon conversion in/before pixel at eta 1.5
Transverse and Longitudinal IP Primary Vertex Tracking Btagging Robustness Object performance Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 9
Impact Parameter Resolutions 10 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) Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi
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 Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 11
Impact Parameter Resolutions Transverse: muon sample (10 muons/event), =50 Generated flat in E and eta (plot vs absolute p and in 4 eta regions) Compare current and upgrade detectors Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 12
Impact Parameter Resolutions Longitudinal: muon sample (10 muons/event), =50 Generated flat in E and eta (plot vs absolute p and in 4 eta regions) Compare current and upgrade detectors Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 13
Primary Vertex Resolution ttbar sample, zero PU and =50 Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 14
Tracking in ttbar 15 ttbar sample, High purity p T > 0.9 GeV/c Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi
Tracking with muons Muon sample High purity p T >1 GeV/c num tracking layers with hits >= 8 Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 16
Tracking Efficiency/Fake Rate ttbar sample, compare current and upgrade detectors High purity, p T > 0.9 GeV/c Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 17
Tracking vs PU Average tracking efficiencies vs PU ttbar, high purity tracks, p T > 0.9 GeV/c Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 18
Tracking vs PU Average track fake rates vs PU ttbar, high purity tracks, p T > 0.9 GeV/c Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 19
B-tagging Performance ttbar, CSV tagger, compare current and upgrade ak5PFjets PFnoPU, jet p T > 30 GeV, DUS,c,b jets 15% absolute gain in b jet efficiency for 1% fake rate Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 20
B-tagging Performance ttbar, CSV tagger, compare current and upgrade, =100 ak5PFjets PFnoPU, jet p T > 30 GeV, DUS,c,b jets Improvement even more impressive at 100 PU Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 21
B tagging performance Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 22 Upgrade as good or better at high pileup as current at low pileup Upgrade PU50 Current PU0 Upgrade PU50 Current PU25
B-tagging Performance vs PU ttbar, CSV tagger, compare current and upgrade, =50 ak5PFjets PFnoPU, jet p T > 30 GeV, DUS,b jets Much better handling high Pile-Up Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 23
Robustness: BPIX1 Inefficiency Study Vary inefficiency of BPIX layer 1: 0%, 5%, 10%, 20% All other layers at 100% ttbar, =50, light quark mis-tag=1% Upgrade detector more robust to BPIX1 inefficiency Grindelwald, 29/08/12 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, =50, high purity tracks, p T >0.9 GeV/c Upgrade detector more robust to BPIX1 inefficiency Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 25
TIB Inefficiency Study Switch off certain modules (in black below) List provided by Frank Hartmann Or consider a uniform 20% inefficiency in TIB1,2 Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 26
Robustness to TIB degradation Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 27 With Dead Modules With 20% uniform inefficiency in TIB1,2 Upgrade detector more robust wrt TIB loss
Small pixel scenario: tracking with ttbar at 100PU Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 28 BPIX Layer1: pixel size 75x100 m 2, 220 m thickness ROC threshold 1200 e - instead of 2000 Significant improvement at 100 PU wrt Upgrade Phase1 detector Good news towards Phase2
Small pixel scenario: btagging performance Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 29 BPIX Layer1: pixel size 75x100 m 2, 220 m thickness ROC threshold 1200 e - instead of 2000 No data loss Significant improvement at 100 PU wrt Upgrade Phase1 detector Good news towards Phase2
ZH llbb H ZZ 4l SUSY M T2 SUSY +MET All analysis show relative improvement and have not been optimized/retuned for high PU Physics Performance Grindelwald, 29/08/12 30 Pixel Upgrade Meeting Alessia Tricomi
ZH llbb Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 31 Analysis based on: 1. triggering on lepton events; 2. kinematic reconstruction of Z from isolated dileptons; 3. reconstructing invariant mass from two b-tagged jets; 4. 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
ZH bb event selection Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 32
ZH bb cut flow Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 33 Values greater than 1 show increased efficiency for the Phase1 upgrade and vice versa
ZH eebb event selection Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 34 Same selection as for muons but Electrons use 95% working-point of VBTF Isolation is relaxed as in the di-muon analysis Dimuon mass ~2 GeV high, so Z mass cut increased by +2 GeV like in dimuon analysis Other criteria same as for di-muon channel
ZH eebb cut flow Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 35 Values greater than 1 show increased efficiency for the Phase1 upgrade and vice versa
ZH llbb results Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 36 ZH bb 65% relative gain in signal efficiency for di-muon channel 75% gain with single muon HLT 175% gain with dimuon HLT (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
H ZZ 4l Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 37 Analysis based on: 1. triggering on di-lepton events; 2. kinematic reconstruction of 2 Zs from isolated di-leptons; 3. 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
H ZZ 4l event selection Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 38 Using same cuts as in 2012 analysis (HIG ) PF leptons used Electrons p T > 7 GeV, | η | 5 GeV, | η | < 2.4 Isolation relaxed from 0.15 to 5.0 |SIP 3D |<4 for each lepton 40 4GeV m 4l > 100 GeV same HLT estimate as in ZH: 3+ pixel hits on trigger leptons
H ZZ 4 cut flow Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 39 Values greater than 1 show increased efficiency for the Phase1 upgrade and vice versa 40% gain in 4 channel
H ZZ 4e cut flow Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 40 Values greater than 1 show increased efficiency for the Phase1 upgrade and vice versa 50% gain in 4e channel
H ZZ 2e2 cut flow Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 41 Values greater than 1 show increased efficiency for the Phase1 upgrade and vice versa 48% gain in 2e2 channel
SUSY M T2 b analysis Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 42 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 M T2 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
SUSY M T2 b event selection Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 43 Good primary vertes Veto electrons: p T >10 GeV/c; | η |<2.4; |d0|<0.04cm; |dz|<1.0cm; missing inner hits<2; PFIso<2.0 Veto muons: p T >10 GeV/c; | η | 10; Pix hits>0; PFIso<2.0 Jets: 2 PF jets with p T > 20 GeV/c passing loose JetID; veto events with jets p T >50 GeV/c but failing jet ID MET: PFMET>30GeV;PFH >750GeV B-tag: Tight CSV tag > 0.898
SUSY M T2 b analysis Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 44 Before any b-taggingOne b-jet required 20% higher signal selection efficiency can be obtained without any real optimization for the new detector and high pile-up.
SUSY +MET analysis Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 45 Di-photon events+MET signature for SUSY No significant SM bkg, small contribution from V 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
SUSY +MET analysis Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 46 Events divided in four classes: , e, ee, fake-fake e and ee samples used to estimate fake rate by fitting Z peak
SUSY +MET analysis Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 47 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
Conclusions Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 48 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 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!
Back-up slides Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 49
Tracking for Upgrade Studies Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 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 IterationSeedsp T cut (GeV) d 0 cut (cm) d z cut (cm) Min hits 0pixel triplets σ bs 3 1low p T pixel triplets σ bs 3 2pixel pairs with vtx σ bs 3 3 detached triplets Apixel +(TEC(1 ring)) triplets BBPIX+TIB triplets TIB, TID, TEC pairs (fewer) TOB, TEC pairs Regular 5_2_0 Tracking steps 50
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 with/without (50PU) dynamic data loss for current detector Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 51
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 with/without (50PU) dynamic data loss for current detector Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 52
Primary Vertex Resolution ttbar sample, zero PU and =50 Compare with/without (50PU) dynamic data loss for current detector Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 53
Tracking Efficiency and Fake Rates Average tracking efficiencies, high purity, p T >0.9 GeV SampleStdgeom Efficiency (%)Phase 1 Efficiency (%) Mu PU0 pt0.9,8hit97.4 ± ± 0.1 Mu PU0 pt0.9,8hit, dloss93.9 ± ± 0.1 Mu PU50 pt0.9,8hit90.1 ± ± 0.1 Mu PU50 pt0.9,8hit, dloss81.5 ± ± 0.1 ttbar PU0 pt ± ± 0.1 ttbar PU0 pt0.9, dloss85.6 ± ± 0.1 ttbar PU50 pt ± ± 0.1 ttbar PU50 pt0.9, dloss79.7 ± ± 0.1 Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 54
Tracking Efficiency & Fake rate 55 Using Standard validation packages: MultiTrackValidator Tracking efficiency = #sim trks assoc. to reco trk #sim trks (for signal sim tracks only) Tracking fake rate = #reco trks not assoc. to sim trk #reco trks (for “all” reco tracks) Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi
Tracking Efficiency/Fake Rate ttbar sample, current detector generalTracks, p T > 0.1 GeV/c Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 56
Tracking Efficiency/Fake Rate ttbar sample, upgrade pixel detector detector generalTracks, p T > 0.1 GeV/c Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 57
Tracking Efficiency/Fake Rate ttbar sample, compare current and upgrade detectors generalTracks, p T > 0.1 GeV/c Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 58
B-tagging Performance (BPIX1 Study) ttbar, CSV tagger, current detector, =50, compare BPIX1 ak5PFjets PFnoPU, jet p T > 30 GeV, DUS,b jets All other layers are at 100% efficiency Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 59
B-tagging Performance (BPIX1 Study) ttbar, CSV tagger, upgrade detector, =50, compare BPIX1 ak5PFjets PFnoPU, jet p T > 30 GeV, DUS,b jets All other layers are at 100% efficiency Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 60
Outer Tracker Inefficiency Study Uniform 20% inefficiency in TIB1,2: zero PU and =50 ttbar sample, high purity tracks, p T >0.9 GeV/c Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 61
Outer Tracker Inefficiency Study Uniform 20% inefficiency in TIB1,2: zero PU and =50 ttbar sample, high purity tracks, p T >0.9 GeV/c Upgrade detector more robust to Outer Tracker inefficiency Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 62
Outer Tracker Inefficiency Study Dead Modules in Outer Tracker: zero PU and =50 ttbar sample, high purity tracks, p T >0.9 GeV/c Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 63
Outer Tracker Inefficiency Study Dead Modules in Outer Tracker: zero PU and =50 ttbar sample, high purity tracks, p T >0.9 GeV/c Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 64
H ZZ 4l analysis Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 65 Isolation
HZ bbll Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 66 Di-lepton requirement
H ZZ 4l analysis Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 67 More pixel hits for muon tracks
H ZZ 4l analysis Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 68 Better IP
H ZZ 4l analysis Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 69 Better Z mass resolution
SUSY M T2 analysis Grindelwald, 29/08/12 Pixel Upgrade Meeting Alessia Tricomi 70