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A. Nikitenko (IC/ITEP), RDMS meeting, March.2009

J et P lus T racks Sub-group of JetMET: RDMS members: I. Vardanyan, N. Ilina, O. Kodolova, A. Nikitenko (convener). AN 2009-031, PAS JME-09-002. A. Nikitenko (IC/ITEP), RDMS meeting, March.2009. Jet+tracks algorithm. The goal of algorithm: correct calorimeter jet

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A. Nikitenko (IC/ITEP), RDMS meeting, March.2009

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  1. Jet Plus TracksSub-group of JetMET:RDMS members: I. Vardanyan, N. Ilina,O. Kodolova, A. Nikitenko (convener) AN 2009-031, PAS JME-09-002 A. Nikitenko (IC/ITEP), RDMS meeting, March.2009

  2. Jet+tracks algorithm The goal of algorithm: correct calorimeter jet energy to the energy of particles at vertex. out-of-calo-cone track in-calo-cone track • Basic algorithm steps: • 0. ZSP and PU off-set corr. • Subtract average expected • response of “in-calo-cone” • tracks from calo jet energy • and add track momentum • Add momentum of “out-of-cone” • tracks Df=0.5 Df=0.5 Jet axis

  3. Step 0: ZSP corrections To be extracted from non ZSP data using single jet triggers

  4. Step 1: correction for response of in-calo-cone tracks EJet = EJetcalo – S<Etrkcalo> + Sptrk , <Etrkcalo> from data without ZSP

  5. Response of pions from TB06no zero suppression

  6. In-calo-cone tracks corrections with TB “jets” Jet was formed from charged pions (p-) randomly selected from the data. Number of pions in jet is fixed: jet consists of 6 pions of 2 GeV 4 pions of 3 GeV 2 pion of 4 GeV 1 pion of 5 GeV thus true jet energy is 37 GeV Average particle response (see previous slide) was subtracted from jet raw energy and replaced by track momentum

  7. Single particle response: effect of ZSP (MC study) Input to JPT: non ZSP response of single pions Effect of ZSP on single pion response

  8. Step 2: adding out-of-calo-cone tracks EJet = EJet+ Sptrk (trks 1,2,3 in fig)

  9. Steps 0-2 in one plot

  10. Take into account tracker inefficiency (I) DEin-cone = ntrkin-cone(pTbin, hbin) x (1-etrk)/etrk x (<pbin> - <Ecalo>) DEout-of-cone = ntrkout-of-cone(pTbin, hbin) x (1-etrk)/etrk x <pbin> etrk = F(pTbin, hbin) – track finding efficiency

  11. Jet Energy Scale and tracker inefficiency

  12. JES uncertainty due to single particle response

  13. Performance for |h|<1.4 Jet Enery Scale ETreco / ETgen Resolution: s(ETreco / ETgen)/m(ETreco / ETgen)

  14. Performance for 1.4<|h|<2.0 Jet Enery Scale ETreco / ETgen Resolution: s(ETreco / ETgen)/m(ETreco / ETgen)

  15. Current JES vs h Still need to take into account ECAL crystal calibration and more accurate response function

  16. ET >40 GeV, barrel Calo vs PF vs JPT Performance in CMSSW_2_2_3, full sim. after L2L3 corrections; “Official” JetMET plot ET> 40 GeV, barrel Latest PF improvements for 31X vs JPT and calo in 2_2_3 (see more in Michele’s talk) Plot provided by P. Janot, no L2L3 corrections applied

  17. Work in progress to improve JPT for 31X releases It was Monte-Carlo. Need time to commission JPT using real data: ZSP, single particle response, tracker efficiency from data;

  18. Track-corrected MET Frank Golf et al. tcMET = MET(corrected for m)– p + 〈E〉 (Replacing expected calorimeter response with track momentum) CMSSW_1_6_X Case where we don’t expect MET … Case where we have true MET … MET tcMET N(MET>30) ≈N(tcMET>30) N(MET>30) ≈ 3 N(tcMET>30) Missing Energy (GeV) Missing Energy (GeV) # of evts with MET>30 GeV (in Z’s) faked by detector resolution and other effects: reduced by factor ~3, while # of W’s almost unaffected as expected. Meeting with LHCC referees 18 Jan 19, 2009

  19. Performance for |h|<1.4 Jet Enery Scale ETreco / ETgen Resolution: s(ETreco / ETgen)/m(ETreco / ETgen) ZSP corrections: corrections for zero suppression on calo sells

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