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The 2011 Tracker misalignment scenario

CMS AlCa meeting Cern, 22/11/2011. The 2011 Tracker misalignment scenario. Motivations for a new scenario. Previous scenario (TrackerAlignment_2010Realistic) provided a worse description of the real remaining misalignment and global deformations on data

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The 2011 Tracker misalignment scenario

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  1. CMS AlCa meeting Cern, 22/11/2011 The 2011 Tracker misalignment scenario

  2. Motivations for a new scenario • Previous scenario (TrackerAlignment_2010Realistic) provided a worse description of the real remaining misalignment and global deformations on data • Aim: a new one which performs closer to the current data alignment in view of 2012 • Mostly in: • DMR/residual distribution in the Endcap • momentum biases in resonances decays (mass VS muon phi) R.Castello

  3. Input dataset and studies performed • Current alignment on data performed mainly with MinBias+Cosmics • A balanced input of ALCARECO (MC): • Isolated muons from W (16.3 M tracks) • Isolated muons from QCD-mu enriched events (2.3 M tracks) • Minbias tracks (450k events ~ 4.5 M tracks) • Zmumu events using mass constraint (390k events) • Peak mode cosmics (1.8 M used tracks) • Deco mode cosmics (1.7 M used tracks) • Opportunely re-weighted to match the pT/h/phi track distribution on data • Several strategies studied: • Starting from Startup MC + bow parameters from data • Starting from ideal MC + small random noise + no bow mis-alignment • Starting from ideal MC + bow parameters from data • different weigh to the cosmic sample • Lesson learned: • Including bow misalignment hit CPU limit: asked for an increasing • The remaining Z mass bias versus muon phi seems to be completely dominated by starting geometry (startup has a too large one w.r.t. data): intermediate starting point • Weighting cosmics (x2, x0.5) has almost no impac: discareded for now R.Castello

  4. Final strategy • Final solution was to create an “intermediate” starting geometry • Module by module differences between Ideal and Startup scenario extracted (D ID-ST) • Differences applied on top of Ideal MC sceanrio and used as starting point for alignment procedure with the input dataset described • Three sizes: • Ideal02= D ID-ST x 0.2 • Ideal03= D ID-ST x 0.33 • Ideal05= D ID-ST x 0.5 • Bowed sensors param from data included as misalignment on top of the starting geometry • Same alignment strategy used for data (one iteration) ID vs Startup ID vs Ideal03 R.Castello

  5. Validation R.Castello

  6. Bowing deformations R.Castello

  7. DMR (Barrel) • Previous scenario already performing good in the Barrel: small changes Ideal MC data geometry Startup MC scenario New MC scenario R.Castello

  8. DMR (Endcaps) • New MC scenario better matches the data in the Endcap • Last improvements in the data alignment are better described by this scenario Ideal MC data geometry Startup MC scenario New MC scenario R.Castello

  9. Mass Vs muon phi • Remaining amplitude (05Delta) closer to data now, w.r.t. previous MC Startup scenario R.Castello

  10. Mass Vs muon phi (Barrel/Endcap) • Different behavior between Barrel EndCap • Closer performance to data in the Endcap, Barrel still a bit optimistic.. • Starting geometry “subdetector dependent” has been produced for accounting this, but no time to validate and sign-off • Potential candidate: MC_idealplus05Delta TEC - Barrel R.Castello

  11. Z mass peak • Good matching in the Z mass shape and resolution Data vs Mcsceanrio_ID05 IDEAL vs Mcsceanrio_ID05 McSceanrio_Ideal05 Caveat: not normalized R.Castello

  12. Validation in other variables: mass vs D(h_mu1; h_mu2) • Overall shift, but trend more similar to data R.Castello

  13. Cosmic track splitting • Not noticeable differences visible • new scenario (BPIX cent) remarkably similar to IDEAL Ideal MC Startup MC scenario New MC scenario (BPIX centered) R.Castello

  14. Summary A new MC misalignment scenario has been produced for the new MC production: • Overall the behavior of the new scenario is quite good in describing the data • Close to the ideal geometry! • It includes bowing deformation fitted in data Ready to be used: already uploaded in the db (PXB centered), see https://hypernews.cern.ch/HyperNews/CMS/get/calibrations/983.html Still room for improvement: • Study on-going for a MC scenario that better matches the data performances in the Barrel region • BUT AlCa+Offline groups had the urgency to move on with the MC production asap to meet the deadlines imposed by the Physics groups. Payloads: TrackerAlignment_2011Realistic_v1_mc TrackerSurfaceDeformations_2011Realistic_v1_mc Credits for this work : A.Agocs, J.Behr, A.Bonato, R.C., G.Flucke, N.Heracleous, K. Krajczár, G. Vesztergombi R.Castello

  15. BACKUP slides R.Castello

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