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Light h 0 decay in SUSY cascade Jet Reconstruction & B tagging. Introduction First use of DST Jet reconstruction and calibration issues B tagging Conclusion . Filip Moortgat (CERN) Alain Romeyer (Mons - Belgium). Introduction. Benchmark point LM5 Tan b = 10 A O = 0 µ > 0
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Light h0 decay in SUSY cascade Jet Reconstruction & B tagging • Introduction • First use of DST • Jet reconstruction and calibration issues • B tagging • Conclusion Filip Moortgat (CERN) Alain Romeyer (Mons - Belgium) Alain Romeyer - March 2005
Introduction Benchmark point LM5 Tan b = 10 AO = 0 µ > 0 M1/2 = 360 GeV M0 = 230 GeV MSUGRA 5 parameters : m0, m1/2,A, tan b, sign(µ) S. Abdullin – L. Pape Update II of the new MSUGRA test points proposal Alain Romeyer - March 2005
Signatures q ~35 % or 85 % b 72 % q b LSP MET p B tagging p Alain Romeyer - March 2005
Signatures… • Main background expected to come from SUSY itself!!! (sbottom…) • 100 000 evt production of all SUSY channels (20% of them contain our signal) • SM background expected small (Z+jets, top…) • rejected by high jet multiplicity and important MET • was not our priority (analysis has just started CRAB & LCG) • Reconstruction strategy • focus on jet reconstruction, b tagging and MET • Access info from DST using ORCA_8_7_2 • test of official Jet Calibration (GammaJet) • Try different Track Counting significance threshold Alain Romeyer - March 2005
DST Jet calibration Only b jets coming from h0 decay(mh = 116 GeV) Alain Romeyer - March 2005
Jet E resolution Only b jets coming from h0 decay(mh = 116 GeV) Alain Romeyer - March 2005
Minv (Signal + SUSY bkg) Alain Romeyer - March 2005
Comparison with private calib. Only b jets coming from h0 decay(mh = 116 GeV) Alain Romeyer - March 2005
Jet E resolution Only b jets coming from h0 decay(mh = 116 GeV) Alain Romeyer - March 2005
IC with 0.7 cone size Only b jets coming from h0 decay(mh = 116 GeV) No calibration for 0.7 cone 0.5 cone calibration used !!! Alain Romeyer - March 2005
Btagging Track Counting Algo. (only b tagged jets) Tag jet if 2 tracks are found above a given Significance threshold Alain Romeyer - March 2005
B tagging eff/mistag IC cone = 0.5 Alain Romeyer - March 2005
Impact on Minv (Signal) Only b jets coming from h0 decay(mh = 116 GeV) Alain Romeyer - March 2005
Minv (Signal + SUSY bkg) Alain Romeyer - March 2005
Conclusion • Jet calibration on DST for 0.5 cone and IC algo is working • Jet reconstruction performance with other cone size cannot be done with DST info (no calibration) • Hardest cut for B tagging Track Counting does not improve the S/B ratio • Solution : try to reconstruct the jet charge • SM bkg analysis started (on LCG using CRAB) in particular for tt inclusive Alain Romeyer - March 2005
Conclusion… Alain Romeyer - March 2005