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Dielectron Spectrum Analysis. J. Leonard 26 August 2009. Today. Action items from e-mail Show us plots with all significant backgrounds and full summer 08 samples. Finish running samples. Samples have all run (rest of Wenu and Wtaunu recovered)
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Dielectron Spectrum Analysis J. Leonard 26 August 2009
Today • Action items from e-mail • Show us plots with all significant backgrounds and full summer 08 samples. Finish running samples. • Samples have all run (rest of Wenu and Wtaunu recovered) • Have histos for all samples, combining into single plots (signal + background) is in progress • Check Z mass plot against Christos to see that normalizations are consistent. Apply a basic electron Id. • Christos’ statistics look like mine • Applied cut sequence from Zee note (AN2009_98, v7) • Optimize analysis and make plots for 10pb-1 • Scaling implemented
Initial spectrum • Signal plot (background plots exist, but not combined yet) • Requirements: • >=2 PAT electrons > 5 GeV • || < 2.5 • Pass 10 GeV single-electron HLT path
Signal spectrum after preselection • Requirements (as-is from Zee note, AN2009_098, v7): • ET of supercluster > 4 GeV • H/E of electron < 0.1 (ratio of energy in HCAL to that in ECAL) • in of electron < 0.02 (difference between of supercluster and of track) • in of electron < 0.1 (difference between of supercluster and of track) • Signal eff. (with respect to initial step): 238969/239391 = 99.8%
pT cut • Requirements (as-is from Zee note, AN2009_098, v7): • pT of electron > 10 GeV • Signal plot (will be combined with BG)
Signal spectrum after pT cut • Signal eff. wrt previous cut: 212765/238969 = 89.0% • Signal eff. wrt initial step: 212765/239391 = 88.9%
Electron ID cuts • Requirements (as-is from Zee note, AN2009_098, v7): • ii < 0.01 for barrel (0.028 for endcap) • RMS shower width in direction • in| < 0.0071 for barrel (0.0066 for endcap) • Difference between of supercluster and of track • Barrel: < 1.4442 • Endcap: 1.560 < < 2.5 • Signal plots (will be combined with BG)
Signal spectrum after electron ID cuts • Signal eff. wrt previous cut: 131736/212765 = 61.9% • Signal eff. wrt initial step: 131736/239391 = 55.0%
Electron isolation cuts • Requirements (as-is from Zee note, AN2009_098, v7): • Sum of ET in HCAL < 8.1 for barrel (3.4 for endcap) • Sum of ET in ECAL < 5.7 for barrel (5.0 for endcap) • Sum of pT of tracks < 7.2 for barrel (5.1 for endcap) • Barrel: < 1.4442 • Endcap: 1.560 < < 2.5 • Signal plots (will be combined with BG)
Spectrum after electron isolation cuts • Signal eff. wrt previous cut: 122866/131736 = 93.3% • Signal eff. wrt initial step: 122866/239391 = 51.3%
Next Steps • Calculate the efficiencies in multiple bins: below and at/above Z peak • See how things change at low end of spectrum • Start thinking about how to optimize cuts • Look at optimization algorithm from Zee note • Make sure I understand variable distributions (like that of ii) • Combine signal and background into single plots • Make table of cut efficiencies for signal and all backgrounds