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Update FTK Meeting 07/13/06 Erik Brubaker U of Chicago.

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Presentation on theme: "Update FTK Meeting 07/13/06 Erik Brubaker U of Chicago."— Presentation transcript:

1 Update FTK Meeting 07/13/06 Erik Brubaker U of Chicago

2 July 13, 2006FTK Meeting2 Outline Tools –Sherpa samples –LVL1 Parametrizations Physics –H  hh  4b Plans Sherpa Samples LVL1 Params LVL1 RateLVL2 Rate Analysis FOM Optimize FOM with rate constraints FTK Performance Signal Samples

3 July 13, 2006FTK Meeting3 Sherpa samples Last meeting, thought final samples were being generated. Several problems uncovered since then.

4 July 13, 2006FTK Meeting4 Sherpa problem #1 2  2-only sample (red) is harder than 2  2+2  3 (green)! Problem in sherpa 1.0.8—parton shower starting scale not clearly defined for 2  2 alone.

5 July 13, 2006FTK Meeting5 Drop 2  2 ME in sherpa All the physics processes we look at so far have 4 final state objects. In a 2  2+2  3 sample, events produced by the 2  2 ME contribute negligibly to trigger rates. Drop 2  2 ME to increase effective statistics.

6 July 13, 2006FTK Meeting6 Sherpa problem #2 (related to #1?) Sample without 2  2 ME has harder 4 th jet. 4 th jet is produced by PS in either case—expect very similar distributions. Plots normalized by cross-section. Events per pb -1

7 July 13, 2006FTK Meeting7 Sherpa problem #3 (from Kohei) Lowering the y cut of the sample should only increase the derived trigger rate by covering more phase space. But rate(y cut =10) < rate(y cut =25)! Related to other problems? Revisit with recent fixes.

8 July 13, 2006FTK Meeting8 Additional sherpa questions Execution time in my setup is longer than the authors see. Strangely, t(MI-on) < t(MI-off). Why not throw this all out the window and use Pythia or Alpgen? –Point was to avoid pythia dijet+PS to describe 3 rd, 4 th jets. But pythia can and should be used as a baseline to compare to. Help from Kohei for jobOptions. –Alpgen is complicated in different ways. SUSY folk are trying to get a validated multijet sample out of it. Could be an option.

9 July 13, 2006FTK Meeting9  LVL1 parametrization For BG processes with real  s, would be useful to have parametrization of LVL1  trigger response to  s. Improvements in ATLAS DDM mean I can access datasets… –SingleTaupt20, 50, 100 copied over. –Can’t use samples with filters! Next step is to run full latest simulation and make response plots for matched  s.

10 July 13, 2006FTK Meeting10 Multi-threshold machinery Rigorous determination of the probability for a given event to pass a given set of jet trigger thresholds (given the LVL1 jet  jet parametrizations) is somewhat complicated. Code available now for the general case at:

11 July 13, 2006FTK Meeting11 LVL1 rates for H  hh  4b Example threshold scan, two thresholds, using full parametrization machinery. Valid for any 4-jet FS. Uses Sherpa MC with known bug  rates too low! 1 st & 2 nd jet threshold 406080100 403.0±0.62.2±0.41.6±0.41.1±0.3 600.035±0.0130.031±0.0090.023±0.008 80(5±3)e-5(4±1)e-5 100(4±2)e-9 3 rd & 4 th jet threshold Bad MC! Rate @ 10 33 cm -2 s -1

12 July 13, 2006FTK Meeting12 Plans Make and check “final” sherpa samples. Use pythia sample as bg rate cross-check. Make  LVL1 parametrization. Understand H  hh  4b cross-section vs m H, m h. Perform threshold scans and optimize observation significance for H  hh  4b with and without FTK. Focus, finish, document by July 26.

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