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ALICE Trigger and Event Selection QA

ALICE Trigger and Event Selection QA. By: Kevin McDermott. August 9, 2012. 2012 Michigan REU Student Program – Final Presentations. ALICE. A Side. C Side. Credit: CERN. Min Bias Trigger Detectors.

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ALICE Trigger and Event Selection QA

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  1. ALICE Trigger and Event Selection QA By: Kevin McDermott August 9, 2012 2012 Michigan REU Student Program – Final Presentations Kevin McDermott

  2. ALICE A Side C Side Credit: CERN Kevin McDermott

  3. Min Bias Trigger Detectors Other rare triggers are used, e.g. EMCal and PHOS, but not used for the purpose of this analysis (only muon production for Period LHC12c) CINT1 Suite = Min Bias Trigger CINT7 Suite = VZERO AND Trigger CINT8 Suite = T0 AND Trigger VZERO C VZERO A T0C T0A SPD Kevin McDermott Credit: ALICE-TDR-011

  4. Physics Selection (PS) • PS validates online trigger conditions and rejects background, used offline before any analysis • ALICE, due to various reasons (defocused beams, the vacuum, and long time integration window of TPC), has significantly worse signal-to-background ratio than the other LHC experiments • Stricter event selection by computing the timing of a signal that passes the triggers to ensure that the event passed occurred at the vertex of ALICE (through the VZERO or T0) • Need a high quality data set to do analysis, thereforeneed to reject background and save actual collisions with high efficiency • Use Quality Assurance (QA) to trend the PS to spot bad runs, monitor beam conditions, and reject clear outliers in analysis Kevin McDermott

  5. ALICE Physics Selection Quality Assurance (PSQA) • Old PSQA done primarily by hand, not automatic • Old PSQA needed streamlining and did not meet proper coding conventions • Built a new class to automatically generate text output per run to be used for newly designed online interface • Same class generates ROOT output of trending QA with TGraphErrors • Built a separate class to handle visualization of run by run trending Kevin McDermott

  6. QA Example: Quick Notes • Plots Naming Convention: • Trigger Class Name [Fast or Regular] Trigger Logic # • Error bars on plots are smaller than the point size due to zoomed out scale. • For ratios that were complete subsets, used binomial errors for error calculation • Otherwise, for uncorrelated ratios, used normal error propagation • The following plot is an example of data taking period LHC12c (May-June 2012) for a given trigger class (in this case, kMUS7) Kevin McDermott

  7. Accepted/All hidden by V0A/All High BG Run Zoom in for example Special note: Only runs 179678 and 179685 use both CINT7 and CINT8. kMUS7: Muon trigger; low pT single muon, offline V0 selection, CINT7 suite Kevin McDermott

  8. As kMUS7 is a CINT7 trigger (V0 AND), V0A sits opposite muon arm, and explains why Acc/All is close to V0A/All. In the same way, V0A/All and Acc/All inversely proportional to V0A BG/All. Kevin McDermott

  9. V0A/All ≅Acc/All inversely proportional to V0A BG/All kMUS7: Muon trigger; low pT single muon, offline V0 selection, CINT7 suite Kevin McDermott

  10. Online Interface: Workflow PS: “Trigger Class [Regular or Fast] Trigger #”: Name of Plotted Ratio, Value, Error PS: "kMUSH7 [Regular] Trigger 3":Accepted/Trigger_class, 0.363665, 0.00283228 Kevin McDermott

  11. Online Interface: Snapshot Note: This is only a preliminary example. All plots produced by the QA run will be instantly viewable on the web. Kevin McDermott

  12. Summary • New AliPSQA class can produce a ROOT file with TGraphErrors that can then be visualized via the AliPSQAVisualization class. • PSQA can be performed automatically by setting just a few input and output parameters. AliPSQA produces text files per run that are automatically processed into trending plots on MonALISA, for immediate access for all ALICE members. • Trending plots can easily identify runs that are clear outliers to be rejected for data analysis in a given period. • When AliPSQA is used in conjunction with run data, trending details are easily understandable. • Results of data taking period LHC12c were presented in ALICE official QA meeting. Kevin McDermott

  13. Acknowledgements • Advisors: Alexander Kalweit and Michele Floris • Lab partner: John Groh • CostinGrigoras • ZaidaConesa Del Valle • CERN, ALICE Collaboration, University of Michigan Kevin McDermott

  14. Questions? Kevin McDermott

  15. BACKUP SLIDES Kevin McDermott

  16. Examples of V0 Timing Run: 179678 Production: ESD muons Trigger class: kMUS7 Kevin McDermott

  17. Examples of V0 Timing Run: 180000 Production: ESD muons Trigger class: kMUS7 Kevin McDermott

  18. Parameters for QA Runs Analyzed: 179678, 179685, 179687, 179796, 179803, 179837, 179859, 180000, 180037, 180039, 180042, 180044, 180110, 180127, 180129, 180130, 180131, 180132, 180158, 180177, 180189, 180190, 180195, 180199, 180200, 180201, 180225 Period: LHC12c Kevin McDermott

  19. Parameters for QA Explanation of QA Data: Trigger class: Number of events in selected trigger class* Accepted: Accepted events V0A and V0C: Events with signal V0A/V0C in collision time window, recomputed offline over all slabs V0A BG and V0C BG: Events flagged as background from V0 T0: Events with T0 signal in collision time window, computed offline T0BG: Events flagged as background from T0 FO >= 1: Number of events with more than 1 chip hit in pixels, computed offline FO >= 2: Number of events with more than 2 chips hit in pixels, computed offline FO (L1) >= 2: Number of events with more than 2 chip hits in the outer layer of the SPD, computed offline Reference: https://twiki.cern.ch/twiki/bin/viewauth/ALICE/PWG1EvSelDocumentation *For the sake of this presentation, all plots with “Trigger class” are renamed in the legend with “All.” Kevin McDermott

  20. QA Results kMUSH7: Muon trigger; high pT single muon, offline V0 selection, CINT7 suite Kevin McDermott

  21. QA Results kMUL7: Muon trigger; like sign dimoun, offline V0 selection, CINT7 suite Kevin McDermott

  22. QA Results kMUU7: Muon trigger; unlike sign dimuon, offline V0 selection, CINT7 suite Kevin McDermott

  23. QA Results Bad run: already flagged in RCT kMuonSingleLowPt8: Muon trigger; low pT single muon, offline T0 selection, CINT8 suite Kevin McDermott

  24. 180037 removed. Kevin McDermott

  25. Bad run kMuonSingleHighPt8: Muon trigger; high pT single muon, offline T0 selection, CINT8 suite Kevin McDermott

  26. 180037 removed. Kevin McDermott

  27. Bad run kMuonLikeLowPt8: Muon trigger; low pTlike sign dimuon, offline T0 selection, CINT8 suite Kevin McDermott

  28. 180037 removed. Kevin McDermott

  29. Bad run kMuonUnikeLowPt8: Muon trigger; low pTunlike sign dimuon, offline T0 selection, CINT8 suite Kevin McDermott

  30. 180037 removed. Kevin McDermott

  31. Online Interface: Parameters Kevin McDermott

  32. Online Interface: Notes • Class AliPSQA with PSQA.C produce output ROOT file with TGraphErrors and text files for MonALISA • TGraphErrors can be visualized with PSQAV.C and AliPSQAVisualization class • All cache/output directories made automatically if they do not exist • List of trigger classes and partitions can be hardcoded, would require TString manipulation. • Current limitations: Size of various data members must be changed by hand if number of trigger classes and/or trigger logic increases Kevin McDermott

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