170 likes | 259 Vues
B-jet tagging with muons. Efficiency of jet and muon reconstruction (bb + X) Discriminating variables Current performance Short look into neural networks Outlook. Jet reconstruction efficiency. 0.7 cone algorithm Reco’d jet compared with mc jet within 0.2 cone ~75% efficient.
E N D
B-jet tagging with muons • Efficiency of jet and muon reconstruction (bb + X) • Discriminating variables • Current performance • Short look into neural networks • Outlook B-Jamboree ~ -tagger O. Peters
Jet reconstruction efficiency • 0.7 cone algorithm • Reco’d jet compared with mc jet within 0.2 cone • ~75% efficient B-Jamboree ~ -tagger O. Peters
Muon reco efficiency B-Jamboree ~ -tagger O. Peters
Muon reco efficiency (ctd) • Total muon reconstruction efficiency ~70% • Combination of Gtrack efficiency and muon efficiency • Efficiency for jet+ reconstruction ~52% B-Jamboree ~ -tagger O. Peters
Discriminating variables • Variables under consideration: • PTRel • P / Ejet • DCA, DCA-significance • DZ, DZ-significance • Current implementation only uses PTRel B-Jamboree ~ -tagger O. Peters
PTRel B-Jamboree ~ -tagger O. Peters
P / Ejet B-Jamboree ~ -tagger O. Peters
DCA & DZ B-Jamboree ~ -tagger O. Peters
DCA & DZ significance B-Jamboree ~ -tagger O. Peters
Current tagger performance bb + + X, 1200 evts, 1843 b-jets, 1131 l-jets B-Jamboree ~ -tagger O. Peters
Current tagger performance bb + X, 1500 evts, 2373 b-jets, 1446 l-jets B-Jamboree ~ -tagger O. Peters
Tagger Performance No requirements on B-Jamboree ~ -tagger O. Peters
Neural net performance • Use a 9-input, 18 hidden, 1 output NN • Inputs are discriminating variables • Trained NN on 950 bbar events • Tested NN on 250 bbar events (not the same!) • Caveat: backgrounds (light jets) come from the same bbar file… B-Jamboree ~ -tagger O. Peters
Neural net output • Solid blue – background • White open – signal B-Jamboree ~ -tagger O. Peters
Neural net performance bb + + X, 200 evts, 320 b-jets, 77 l-jets Grey: Values from currently implemented tagger B-Jamboree ~ -tagger O. Peters
Neural net performance bb + X, 1500 evts, 2373 b-jets, 1446 l-jets Grey: Values from currently implemented tagger B-Jamboree ~ -tagger O. Peters
Outlook • Discriminating variables are shaping up • Neural network is looking promising • Need more MC, especially background • cc • QCD di-jet B-Jamboree ~ -tagger O. Peters