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Muon Isolation Update. Ken Johns University of Arizona. Z, Zj, Zjj Data = “Signal”. Sample Emily Z skim Cuts Good vertex 2 muons with P T > 15 GeV/c 1 isolated muon Same vertex Muon phi (highest P T ) – metphi < 165 degrees Corrected MET < 15 GeV 75 < dimu mass < 105 GeV/c 2
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Muon Isolation Update Ken Johns University of Arizona
Z, Zj, Zjj Data = “Signal” • Sample • Emily Z skim • Cuts • Good vertex • 2 muons with PT > 15 GeV/c • 1 isolated muon • Same vertex • Muon phi (highest PT) – metphi < 165 degrees • Corrected MET < 15 GeV • 75 < dimu mass < 105 GeV/c2 • 0, 1, >1 jets with ET > 20 GeV • Look at distributions of the “other” muon
bb p13 Data = “Background” • Sample • Dimu p13 skim • Cuts • Good vertex • 2 muons with PT > 6 GeV/c • // ΔR > 0.5 between the two muons • 1 muon with an associated jet • Same vertex • Muon phi (highest PT) – metphi < 165 degrees • Corrected MET < 15 GeV • 0 < dimu mass < 70 GeV/c2 • >1 jets with ET > 20 GeV • Look at distributions of the “other” muon
bb rat efficiency = f(Ptmu) • Rat == Halo11 / Ptmu • Let Ptmu = 6, 10, 12, 15 GeV/c • Define Rat cut where background efficiency = 10% • 6 GeV/c = 0.32 • 10 GeV/c = 0.30 • 12 GeV/c = 0.28 • 15 GeV/c = 0.25 • => Only slowly varying with Ptcut • => But other isolation variables change slightly with Ptmu cut as well (statistics?)
Signal Efficiency • Signal efficiency for 10% background (bb) efficiency • Use 12 GeV/c cut sample for bb background (more statistics than 15 GeV/c) • (Arbitrarily) set background efficiency to 10% • Halo11 efficiency for signal (@3.8) = 75% • Trkpt efficiency for signal (@2.0) = 50% • Rat efficiency for signal (@0.28) = 92% • dR efficiency for signal (@0.5) = 75% • Rat still in the running as isolation variable • Note dR inefficiency as well • n.b. previous efficiencies used Ptmu = 6 GeV/c to determine bb cut points
p14 Zjj Data-MC Isolation Comparison • Pick signal efficiency = 90% • Ask what cut value gives this efficiency • Here Ptmu cut = 15 GeV/c • Halo11 • Data = 6.4, MC = 3 • Trkpt • Data = > 10, MC = 4 • Rat • Data = 0.35, MC = 0.1