Update on Lepton+Jets+MET mSUGRA LM-1: Systematic Uncertainty Decomposition

1. Update on Lepton+Jets+METmSUGRA LM-1:Systematic Uncertainty Decomposition Rick & Bobby R. Cavanaugh, SUSY/BSM Working Group Meeting

2. Motivating Example:MET (uncorr) From Towers Total Background LM-1 Signal Events Rapidly falls HLT Applied  Since this is a Counting Experiment, look at cumulative events passing cuts… Flatter MET [GeV] R. Cavanaugh, SUSY/BSM Working Group Meeting

3. Motivating Example:MET (uncorr) From Towers Total Background LM-1 Signal Rapidly falls: - B / MET large Naïve expectation: Small systematic effects affecting MET might lead to large differences in S / S+B Cumulative Num. Events Passing Cut Flatter: S / MET small Cut on MET [GeV] R. Cavanaugh, SUSY/BSM Working Group Meeting

4. Statistical: S+B Systematical: Finite MC Statistics NW / Ngen QCD level (not shape) 50% Jet Energy Scale 10% ET (affects also MET) Jet Energy Resolution Additional one ET smearing (ET taken from the DAQ TDR) (affects also MET) For Jet Systematics N = number of events passing cuts before systematic effect applied Nsyst = number of events passing cuts after systematic effect applied Uncertainty [number of events]: B = N – Nsyst Uncertainty Definitionsconsidered so far… R. Cavanaugh, SUSY/BSM Working Group Meeting

5. Statistical: S+B Systematical: Finite MC Statistics NW / Ngen QCD level (not shape) 50% Jet Energy Scale 10% ET (affects also MET) Jet Energy Resolution Additional one ET smearing (ET taken from the DAQ TDR) (affects also MET) For Jet Systematics N = number of events passing cuts before systematic effect applied Nsyst = number of events passing cuts after systematic effect applied Uncertainty [number of events]: B = N – Nsyst Uncertainty Definitionsconsidered so far… Quick side remark: 10% seems conservative for this study (we assumes 10 fb-1) Plan to vary JES systematic according to expected dependence on integrated luminosity 8-10% for L < 1fb-1 ~3% at some point after 1fb-1 R. Cavanaugh, SUSY/BSM Working Group Meeting

6. Statistical: S+B Systematical: Finite MC Statistics NW / Ngen QCD level (not shape) 50% Jet Energy Scale 10% ET (affects also MET) Jet Energy Resolution Additional one ET smearing (ET taken from the DAQ TDR) (affects also MET) For Jet Systematics N = number of events passing cuts before systematic effect applied Nsyst = number of events passing cuts after systematic effect applied Uncertainty [number of events]: B = N – Nsyst Uncertainty Definitionsconsidered so far… Quick side remark: 10% seems conservative for this study (we assumes 10 fb-1) Plan to vary JES systematic according to expected dependence on integrated luminosity 8-10% for L < 1fb-1 ~3% at some point after 1fb-1 Many systematics not yet considered (PDFs, muon ID eff, etc) R. Cavanaugh, SUSY/BSM Working Group Meeting

7. Systematic UncertaintyDecomposition Statistical MC Statistics QCD Jet E Scale Jet E Resolution Total HLT Applied Uncertainty [number of events] Cut on MET [GeV] R. Cavanaugh, SUSY/BSM Working Group Meeting

8. Toy “Significance” Decomposition NOTE: The following plots have HLT applied, MET cuts applied NO OTHER CUTS APPLIED!  significant optimisation still possible (likely) • Statistical only • S / S + B • Statistical + MC Statistics • S / S + B + BMC2 • Statistical + QCD level • S / S + B + 0.5BQCD • Statistical + Jet Energy Scale • S / S + B + BJES2 • Statistical + Jet Energy Resolution • S / S + B + BRES2 • Total • S / S + B + BMC2 + 0.5BQCD + BJES2 + BRES2 R. Cavanaugh, SUSY/BSM Working Group Meeting

9. Toy “Significance” Decomposition Statistical only Statistical + MC Statistics Statistical + QCD Statistical + Jet E Scale Statistical + Jet E Resolution Total “Significance” HLT applied, MET cuts applied NO OTHER CUTS APPLIED!  significant optimisation still possible (likely) Inclusion of different systematics tend to prefer higher MET cut values HLT Applied Cut on MET [GeV] R. Cavanaugh, SUSY/BSM Working Group Meeting

10. Observations • Systematics in toy “significance” definition: • Shift to higher MET cut values preferred • Overall reduction in toy “significance” estimation • JetMET Uncertainties • Current choices dominate (no JetMET recommendation yet) • Jet Energy Scale: 10% ET • Jet Energy Resolution: additional one unit of ET smearing • Finite MC Statistics Uncertainty • Important, but does not currently dominate!! • Finite MC Statistics: NW / Ngen • QCD Level (not-shape) Uncertainty • Not important compared with others (but, prob. too optimistic) • QCD level: 50% R. Cavanaugh, SUSY/BSM Working Group Meeting

11. Conclusion • Everything still very preliminary! • Healthy discussion about Finite MC Statistics Systematic arising from 06 Sept. SUSY/BSM Meeting • Selection optimisation underway… • Toy “significance” estimate currently being used • Inclusion of systematic effects being studied • Likelihood ratio method being implemented • Will be used for final results • Early observations suggest that • Systematics can have a strong effect • JetMET systematics are important to understand and correctly estimate • Current assumptions may be conservative? • Need official recommendation from JetMET assuming 10 fb-1 data collected • We are still collecting additional statistics • Y. Pakhotin has produced trees for all available ttbar! • We are working to include more W+jets • Will include Alpgen samples when available R. Cavanaugh, SUSY/BSM Working Group Meeting