1. R. Castello (UC Louvain) on behalf of the Tracker alignment group The 2011 Tracker misalignment scenario CMS AlCa meeting Cern, 22/11/2011

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.Castello2

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/  /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.Castello3

4. Final strategy  Final solution was to create an “intermediate” starting geometry  Module by module differences between Ideal and Startup scenario extracted (  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=  ID-ST x 0.2  Ideal03=  ID-ST x 0.33   Ideal05=  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) R.Castello4 ID vs Startup ID vs Ideal03

5. Validation R.Castello5

6. Bowing deformations R.Castello6

7. DMR (Barrel)  Previous scenario already performing good in the Barrel: small changes R.Castello7 Ideal MC data geometry Startup MC scenario New MC scenario

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 R.Castello8 Ideal MC data geometry Startup MC scenario New MC scenario

9. Mass Vs muon phi  Remaining amplitude (05Delta) closer to data now, w.r.t. previous MC Startup scenario R.Castello9

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 R.Castello10 TEC - Barrel

11. Z mass peak  Good matching in the Z mass shape and resolution R.Castello11 McSceanrio_Ideal05 IDEAL vs Mcsceanrio_ID05 Data vs Mcsceanrio_ID05 Caveat: not normalized

12. Validation in other variables: mass vs  (  _mu1;  _mu2) R.Castello12  Overall shift, but trend more similar to data

13. Cosmic track splitting  Not noticeable differences visible  new scenario (BPIX cent) remarkably similar to IDEAL R.Castello13 Ideal MC Startup MC scenario New MC scenario (BPIX centered)

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.Castello14

15. BACKUP slides R.Castello15