DT Simulation Validation

1. DT Simulation Validation J. Santaolalla, B. de la Cruz (CIEMAT, Madrid) Muon Barrel Workshop, 28th September 2010

2. Outline • DT Simulation Validation: • SimHits • Digis • RecHits • Segments • Description of Validation Twiki Page

3. DT Simulation Validation Quantities validated: SimHits: Test of Geometry, Occupancies, muon hits generated, energy deposited in gas, loss of muon momentum traversing magnet yoke… Digis: SimHits digitization using smeared Garfield parametrization, with some corrections. Test number of digis and time distribution. RecHits: Single hit resolution and pulls with a granularity of chambers. Dependence with muon incident angle, hit position in cell. Segments: Spatial and angular resolutions, pulls. ■At this level, validation programs well established and automatized, only occassional changes in validation code. ■ This fact resembles stability of muon simulation.

4. DT Validation samples ►MC samples: ■Standard validation procedure up to now. ■Allow to validate different CMSSW versions. ■ Uses Simulated RelVal files ►Single muon files (flat in , , fixed pt) with ideal detector conditions ►Physical process production (Z, top) with Startup (realistic) conditions usually  10000 evts per sample. ►Real data : ■ from Cosmics Runs  useful to establish first calibrations and first parameters values, ■ from pp Collisions  already enough statistics to be used as well for Validation, from now on

5. Outline • DT Simulation Validation: • SimHits • Digis • RecHits • Segments • Description of Validation Twiki Page

6. DT SimHits: Geometry /RelValSingleMuPt100/ Collision Data Run 143953 Qualitative MC-Data Comparison SingleMuon MC MB4 MB3 Wheel 0 MB2 MB1 Cell number MB4 SimHit Validation checks Geometry and Occupancies in Simulation, but without realistic detector conditions ■ No noisy cells ■ No missing cells, layers… MB3 MB2 MB1 Cell number From DT offline analysis: /cms/MUON/dt/sx5/Results/GlobalRuns/Beam2010/Collisions

7. DT SimHits: Occupancies /RelValSingleMuPt100/ Collision Data Run 143953 SingleMuon MC Wheel -2 Wheel +2 All Wheels Wheel -1 Wheel +1 Wheel 0 MB4 2nd station S4, S10 All Sectors ■Highest occupancies in W0 and smallest in W2 (Sim & Data) ■ Comparison just qualitatively as data contains noise and hits outside time window not simulated.

8. DT SimHits /RelValSingleMuPt100/ MC ●Data SingleMuon MC  Distrib  Distrib Collision Data Run 143953

9. Outline • DT Simulation Validation: • SimHits • Digis • RecHits • Segments • Description of Validation Twiki Page

10. DT Digitization in Simulation Chain • Parameters entering the digitization: • Drift velocity (from Garfield parametrization), takes into account non-linearities, B field effects • Velocity of Propagation along wire = 24.4 cm/ns • Deadtime between 2 digis in same cell = 150ns • Muon TOF Correction (1 per SL) • To_like_delay(offset) Validation: • Drift Time Distributions (Timeboxes) • Number of Digis generated from original SImHits

11. DT Digis comparison: simulated-real data Collision Data Run 143953 Time (ns) Simulated data from RelVal single muon Comparison of timeboxes distributions in real and simulated data is quite good, although occassionally real effects appear… Time (ns)

12. DT Digis in real data Examples: noisy/missing cells Due to noisy cells in layer 4 Due to missing cells in layer 1 Unphysical signals in drift time distributions Small signal in layer 1 Unphysical signals in drift time distributions Time (ns Due to noisy cells in layer 4 Cell number Cell number

13. Simulation of Detector Real Conditions • The DT muon simulation is becoming more realistic now (parameters and resolutions now injected from muons from collisions and not CRAFT) but nevertheless real conditions (noisy cells, dead cells, etc ) not included in simulation, but stored in DB and ready to be used at reco level, if needed. • Dead cells: negligible number of disconnected cells ( 0.5%) • Noisy cells: DT Noise rate (5Hz) is coming from isolated single cells with high hit rate • for the moment not included in simulation, but could be masked at Reco level if convenient. Do we (DTs) need that simulation cope with IOV-dependent conditions of the detector, following the DT chambers status along time? Probably not at SIM level, but at RECO one

14. Outline • DT Simulation Validation: • SimHits • Digis • RecHits • Segments • Description of Validation Twiki Page

15. RecHits • Comparison SimHit – RecHit (resolution and pull) for: • 1D RecHits • Step 1 • Step 3 • Granularity • Plots split by wheel, chamber and view (phi, Z) • Samples: • RelValSingleMuPt100  MC IDEAL conditions • RelValZMM  MC STARTUP conditions • Also…: • Resolution/Pull vs Eta • Resolution/Pull vs Phi • Resolution/Pull vs Impact angle • Resolution/Pull vs Distance to wire

16. RecHits (some plots) CMSSW381 Resolution S1 Rphi (all wheels,…) RelValSingleMuPt100 RecHit - SimHit (cm) μ = -0.003 (cm) σ = 0.026 (cm) Angle (rad) Phi (rad) RecHit - SimHit (cm) RecHit - SimHit (cm) Distance to wire (cm) eta

17. RecHits (some plots) CMSSW381 Pull 1D S1 Rphi (all wheels,…) RelValSingleMuPt100 Angle (rad) Distance to wire (cm) Same for Step 3, RZ,… In total 302 plots for each sample (MuPt100 and ZMuMu)

18. Outline • DT Simulation Validation: • SimHits • Digis • RecHits • Segments • Description of Validation Twiki Page

19. DTSegments • Similar plots to RecHits ones • Comparison SimHit (segment) – RecHit (segment) with resolution and pull plots for: • x position, y position, α angle, β angle • 2D and 4D segments • Granularity • Plots split by wheel • Samples: • RelValSingleMuPt100  MC IDEAL conditions • RelValZMM  MC STARTUP conditions • Also…: • Resolution/Pull vs Eta • Resolution/Pull vs Phi

20. DTSegments CMSSW381 Resolution Rphi (all wheels,…) RelValSingleMuPt100 RESIDUAL PULL μ = -2e-5 (cm) σ = 0.010(cm) RecHit – SimHit (cm), segment x pos

21. Outline • DT Simulation Validation: • SimHits • Digis • RecHits • Segments • Description of Validation Twiki Page

22. Web site • All plots in the web site: • http://cms-service-dtrechitvalidation.web.cern.ch Easy to browse

23. Spotting problems... CMSSW381 CMSSW382 RelValSingleMuPt100 Pull ? Narrower Resolution ? Longer Tail

24. Spotting problems... CMSSW381 CMSSW382 RelValSingleMuPt100 Pull Due to a more realistic vdrift table (OK) More realistic errors (OK) Resolution

25. Conclusions • DT Validated in four steps: SimHits, Digis, RecHits, and Segments • Validation programs quite stable and established, only occasional developments. • Still to improve: MC-Data comparison. • Public web page to check changes in RecHits and Segments • Plots used shown to be useful to spot problems or as a confirmation of changes.