Pixel Phase 1 Physics/Simulations (Fermilab) for the Tracker Upgrade Simulations Group Pixel Phase 1 Physics/Simulations Harry Cheung (Fermilab) for the Tracker Upgrade Simulations Group CMS Upgrade Workshop, 7 Nov 2011 H. W. K. Cheung (FNAL) 1 Focus on readiness for Physics Case for Pixel Upgrade TDR Tracking Performance Software and Computing Issues for Physics Case

Simulation Studies Simulation software for TDR studies Using CMSSW release CMSSW_4_2_3_SLHCx with CMSSW_4_4_X tracking (handles high PU better) Not moving releases until we have results on the ZHbb analysis for TDR Full (GEANT4) simulation used for tracking studies: tracking efficiency and fake rates, b-tagging studies Modified Fastsimulation for physics studies (but see later) Results to be included in the TDR Effect of new ROC (reduce data loss) Effect of additional pixel layer Recovery of efficiency in case of TIB inefficiency Effect of smaller pixel size/closer radius (Phase 1b) Effect of upgrade on a physics channel (boosted ZHbb) CMS Upgrade Workshop, 7 Nov 2011 H. W. K. Cheung (FNAL) 2

Upgrade Tracking Study at =50 (100) for 25 (50) ns crossing time Data loss used in simul. due to ROC/readout limitations (from TP) Do we have new data loss numbers for redesigned ROC chip? Tracking steps modified for upgrade geometry and high PU Extra layer: quadruplet seeds and efficient triplet seeding (3-out-of-4) Tuning of tracking steps for of 50 and 100 to reduce fakes Drop pair seeds, low pT seeds, and detached tracking steps Optimization still ongoing CMS Upgrade Workshop, 7 Nov 2011 H. W. K. Cheung (FNAL) 3 Current Detector Radius (cm) % Data loss at 2  10 % Data loss at 2  10 BPIX BPIX BPIX FPIX1& Phase 1 Detector Radius (cm) % Data loss at 2  10 % Data loss at 2  10 BPIX BPIX BPIX BPIX FPIX

Effect of ROC Data Loss Loss of efficiency for tracking (ttbar, =50, high purity tracks) CMS Upgrade Workshop, 7 Nov 2011 H. W. K. Cheung (FNAL) 4 No data loss With data loss Efficiency eta pTpT Fake Rate Phase 1 Upgrade Geometry Current Geometry

Effect of ROC Data Loss Worsening of b-tagging ( =50, ttbar) CMS Upgrade Workshop, 7 Nov 2011 H. W. K. Cheung (FNAL) 5 Phase 1 Upgrade Geometry Current Geometry CombinedSecondaryVertex b-tagging algorithm

Effect of Extra Layer Using MultiTrackValidator, ttbar sample, high purity tracks CMS Upgrade Workshop, 7 Nov 2011 H. W. K. Cheung (FNAL) 6 Current Pixel Geometry Phase 1 Upgrade Geometry Efficiency eta pTpT Fake Rate =50 with (Pixel ROC) data loss =50 no data loss

Effect of Extra Layer Improvement for b-tagging ( =50, ttbar) Already significant Improvement for upgrade geometry even without ROC data loss CMS Upgrade Workshop, 7 Nov 2011 H. W. K. Cheung (FNAL) 7 =50 with (Pixel ROC) data loss =50 no data loss CombinedSecondaryVertex b-tagging algorithm

Tracking Efficiency & Fake rate Using MultiTrackValidator, ttbar sample, high purity tracks CMS Upgrade Workshop, 7 Nov 2011 H. W. K. Cheung (FNAL) 8 Current Pixel Geometry Phase 1 Upgrade Geometry Efficiency eta pTpT Fake Rate No Pileup Upgrade improves tracking efficiency, and fake rates at high PU

Transverse IP Resolutions vs p Compare Std Geometry and Phase 1 zero PU using muons CMS Upgrade Workshop, 7 Nov 2011 H. W. K. Cheung (FNAL) < η < < η < < η < 1.50 < η < 1.0 Current Pixel Geometry Phase 1 Upgrade Geometry

Longitudinal IP Resolutions vs p Compare Std Geometry and Phase 1 zero PU using muons CMS Upgrade Workshop, 7 Nov 2011 H. W. K. Cheung (FNAL) < η < < η < < η < 1.50 < η < 1.0 Current Pixel Geometry Phase 1 Upgrade Geometry

Primary Vertex Resolution vs N tk Using ttbar, we want to demonstrate why the resolution gets more worse for stdgeom (still under study) CMS Upgrade Workshop, 7 Nov 2011 H. W. K. Cheung (FNAL) 11 No pileup =50 Transverse Longitudinal Current Pixel Geometry Phase 1 Upgrade Geometry

B-Tagging Performance Compare =100, ttbar, no tuning of b-tag algos CMS Upgrade Workshop, 7 Nov 2011 H. W. K. Cheung (FNAL) 12 Need tuning and optimization of tracking and b-tagging algorithms at =100. Do we show this in TDR? We are investigating the offset at high PU Relevant if we run with 50 ns crossing time at 2×10 34 cm -2 s -1

Phase 1b Studies, etc. In progress of getting results for Phase 1b Now just doing 75x100 μm 2 pixel PXB, 200 μm thk, 2000e threshold Will make the same plots as regular pixel size (IP and PV resolutions, tracking efficiency and fake rate, b-tagging) Not likely to get results for a physics analysis In progress of updating PXB geometry and beampipe Once we have results we can update the plots using this (this is the new PXB baseline with 12 faces for layer 1) Not shown here, but we are also updating the TIB inefficiency study plots CMS Upgrade Workshop, 7 Nov 2011 H. W. K. Cheung (FNAL) 13

Phase 1b Studies Resolution plots from MTV (not plotted against absolute p) CMS Upgrade Workshop, 7 Nov 2011 H. W. K. Cheung (FNAL) 14 eta pTpT TransverseLongitudinal pTpT Phase 1 Smaller Pixel Size

Simulations for Physics Case Study the boosted ZH  μbb-bar channel as in the TP Channel still relevant in the >100 fb -1 regime Use CMSSW simulation instead of generator analysis used in TP Use Modified Fastsim: simhits (including PU) from fastsim but then the regular Fullsim digi steps and full track pattern recognition Faster and lower memory usage, Fullsim digi+reco step needs >4GB RAM/job slot (max 2-3 GB/slot on GRID) Some mismatch, need to compare eff/mass distr to use it or not Will not do 100 PU samples CMS Upgrade Workshop, 7 Nov 2011 H. W. K. Cheung (FNAL) 15 GeometryPhase 1 (s)Current (s) Fulsim (CPU/evt) GEN+SIM8883 Fullsim (CPU/evt) digi+full reco PU= Modified Fastsim (Full process) PU=5039 (4.4x faster)17 (8.8x faster) Fullsim (CPU/evt) digi+full reco PU=100~ Modified Fastsim (Full process) PU= (4.6x faster)58 (5.9x faster) ttbar: LPCCAF

“Validate” Modified Fastsim 4 Physics Compare modified Fastsim vs Fullsim, ttbar, =50 Modified Fastsim: use Fastsim for simhits & pileup only CMS Upgrade Workshop, 7 Nov 2011 H. W. K. Cheung (FNAL) 16 Phase 1 geometryCurrent Geometry Fullsim Modified Fastsim

Tracking Efficiency & Fake rate Compare Fastsim, Muon gun (flat p T ), =50 Modified Fastsim: use Fastsim for simhits & pileup only CMS Upgrade Workshop, 7 Nov 2011 H. W. K. Cheung (FNAL) 17 Phase 1 geometryCurrent Geometry Fullsim Modified Fastsim

B-Tagging Performance Compare Fastsim, ttbar, No Pileup Modified Fastsim b-tagging performance similar for a wide operating CMS Upgrade Workshop, 7 Nov 2011 H. W. K. Cheung (FNAL) 18 CombinedSecondaryVertex b-tagging algorithm Phase 1 geometryCurrent Geometry

B-Tagging Performance Compare Fastsim, ttbar, =50 Modified Fastsim b-tagging performance similar for a wide operating range of b-jet b-tagging efficiencies (despite fake rate difference) CMS Upgrade Workshop, 7 Nov 2011 H. W. K. Cheung (FNAL) 19 CombinedSecondaryVertex b-tagging algorithm Phase 1 geometryCurrent Geometry

B-Tagging Performance Compare Fastsim, ttbar, =50 Modified Fastsim b-tagging performance looks similar enough at =50 to do comparative physics studies CMS Upgrade Workshop, 7 Nov 2011 H. W. K. Cheung (FNAL) 20 CombinedSecondaryVertex b-tagging algorithm FullsimModified Fastsim

B-Tagging Performance However! Compare Fastsim, ttbar, =100 Modified Fastsim b-tagging performance very different from Fullsim! Need to investigate CMS Upgrade Workshop, 7 Nov 2011 H. W. K. Cheung (FNAL) 21 CombinedSecondaryVertex b-tagging algorithm Current GeometryPhase 1 geometry

MC Samples Requested 10K Fullsim signal & background samples produced Samples look okay to proceed with large samples 10K modified Fastsim samples being validated Fullsim GEN-SIM samples requested, being processed Need to request digi+reco with AOD output after this Data production team is already saying there is a problem (>2GB) Will work with CMS VHbbAnalysisNewCodeVHbbAnalysisNewCode Learning stage (more complex than generator analysis) CMS Upgrade Workshop, 7 Nov 2011 H. W. K. Cheung (FNAL) 22 ChannelDescriptionNumber Requested ZH  μbbHERWIGPP_POWHEG_H120_bbbar_Z_ll_14TeV250K ttbarTTbar_Tauola_14TeV500K ZZZZ_MMorBB_TuneZ2_14TeV_pythia6_tauola500K (may need 2M?) Z+jetsZMM_14TeV500K (may need 36M?) Minbias for PUMinBias_14TeV2.5M

Issues and Concerns We have basically in hand all the plots we had for the TP but updated to the latest CMSSW version We are still getting the Phase 1b plots Should have additional plots showing understanding of effect of PU Very slow progress with physics analysis Mainly due to lack of resources (manpower) Expected dedicated (Tracker) physics coordinator – did not materialize Now need to push on with the people we have (now 2 new people) Very little time, but at least we now seem to have a team of people to work on this (names reflect my current personal understanding) Eric Brownson/Carlos Maca, Mark Grimes, (Helena Malbouisson), Robert Stringer Also need to push on getting the samples (CPU resources) Should present comparisons of the high PU data (30 PU) with MC Studies ongoing in Tracking POG but they could use help CMS Upgrade Workshop, 7 Nov 2011 H. W. K. Cheung (FNAL) 23

Backup Slides CMS Upgrade Workshop, 7 Nov 2011 H. W. K. Cheung (FNAL) 24

Pixel Phase 1 Geometry Phase 1 pixel detector replacement 4 barrel layers, outermost layer closer to TIB 3 FPIX disks per side, split into inner and outer disks New ROC chip, readout, power, cooling, etc.: Total material less than in current pixel detector CMS Upgrade Workshop, 7 Nov 2011 H. W. K. Cheung (FNAL) 25 Phase 1 BPIX geometry Current BPIX geometry

CMS Upgrade Workshop, 7 Nov 2011 H. W. K. Cheung (FNAL) 26 Pixel Upgrade Material Budget Reduced material even with more layers “Volumes”Mass (g) CurrentDesign 2015As Simulated BPIX  < FPIX  < Rad. Len.Nucl. Int. Len. Dots - std geom Green Hist - R39 Pixels

CMS Upgrade Workshop, 7 Nov 2011 H. W. K. Cheung (FNAL) 27 Standard Tracking Steps 4_4_0_pre6 tracking steps: includes pair seeds, lower pT seeds, and detached tracks IterationSeedsp T cut (GeV) d 0 cut (cm) d z cut (cm) Min hits Max lost hits 0pixel triplets σ bs pixel triplets σ bs 31 1pixel pairs with vtx pixel triplets σ bs 31 3Apixel +(TEC(1 ring)) triplets BBPIX+TIB triplets TIB, TID, TEC pairs (fewer) TOB, TEC pairs

Tracking Efficiency & Fake rate Using MultiTrackValidator CMS Upgrade Workshop, 7 Nov 2011 H. W. K. Cheung (FNAL) 28 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)