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-B tagging in D0. Ultimate goal: b-jet cross section at s = 2.0 TeV Approach Current results Future plans. Approach. Use properties of and jet (only) Discriminate between background and signal Current discriminators: P muon P TRel between and jet P LRel between and jet
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-B tagging in D0 Ultimate goal: b-jet cross section at s = 2.0 TeV • Approach • Current results • Future plans -B tagging status
Approach • Use properties of and jet (only) • Discriminate between background and signal • Current discriminators: • Pmuon • PTRel between and jet • PLRel between and jet • Use Run I experience! PTRel jet -B tagging status
Background • /Ks decaying to in calorimeter • Punch through • W (ttbar) -B tagging status
Data samples • ttbar, 5000 events • Biases in signal and background? • Waiting for QCD sample • Problem: only 11% of b quarks decay to • Need big sample -B tagging status
Results - PTRel MC blue: b purple: c bc green: background = MC jet = MC -parent -B tagging status
Results - PTRel Reco jet, MC -B tagging status
Results - PTRel Reco jet, Reco -B tagging status
Results - P MC -B tagging status
Results - P Reco -B tagging status
Conclusion • Jet direction not always a good measurement for heavy quark direction • Muon gets poorly reconstructed in some cases • Need to debug reconstruction code • Currently hard to get discriminants with reconstructed values -B tagging status
Outlook • Improve reconstruction • Investigate performance of discriminators • From March 1st: debug real data • From ~July 2001: • Analyze real data • Calculate cross section -B tagging status