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Status of JetsMET

Status of JetsMET. PRS: Physics Reconstruction and Selection HCAL/JetsMET group. Shuichi Kunori U. of Maryland 18-May-2001. HCAL - Jets/MET. S.Eno / S.Kunori - Coordinator http://home.fnal.gov/~sceno/jpg/Default.htm Dates: End 2002 DAQ TDR (end 2001 for HLT section)

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Status of JetsMET

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  1. Status of JetsMET PRS: Physics Reconstruction and Selection HCAL/JetsMET group Shuichi Kunori U. of Maryland 18-May-2001

  2. HCAL - Jets/MET • S.Eno / S.Kunori - Coordinator • http://home.fnal.gov/~sceno/jpg/Default.htm • Dates: • End 2002 DAQ TDR (end 2001 for HLT section) • End 2004 Physics TDR • Organization: • HCAL simulation – Sunanda Banerjee (TIRF) • CMSIM/GEANT4/FAST • Verify shower model in G4. • Calibration & Monitoring – Olga Kodolova (MSU) • energy scale of jets, MET, tau • -> from detector construction/commission to in-situ calibration. • HCAL in ORCA – Salavat Abdoullin (Maryland) • readout simulation + … • Physics objects with HCAL – Sasha Niketenko (CERN/ITEP) • jets, MET & tau

  3. DAQ TDR (P.Sphicas, Nov.20, 2000) For both low and high luminosity We will cover all of these!

  4. Main Issues Many physics analyses require - low ET jets: from top, W, Higgs from WW fusion part of signal background rejection (e.g. jet veto) - High luminosity pile-up energy low ET jets from overlapping events fake jets due to pileup. - tjet - b jet (tag) - Correct energy scale from low ET to very high ET - Better resolution for Jet/MET ET range 20GeV-2TeV

  5. PT (lepton) h ET(b-quark)h <2.5 >20GeV 20-100 <2.5 0 200 -2 +2 0 200 -4 +4 MT (l+n) MET ET(tagging jet)h 2.5-4.0 >50GeV 50-100 >20GeV 0 200 -4 +4 0 200 0 200 Single Top - Kinematics 250pb Measurement of - Vtb / top decay properties / background to new physics

  6. Forward tagging jets &Higgs Couplings measurement Although s(VBF)~s(GF)/3, VBF process may play a big role in measurement of higgs properties in addition to discovery potential.

  7. t jet 1 tb tn 10-2 10-4 Branching ratios for H+ 1 tb 10-2 tn 1 prong t decay (t jet) 10-4 M(H+) 200 500 1000

  8. t jets • tau jet: • narrow (one prong) jet • L1/L2: • use only calorimeter • L1: 0.087x0.087 • L2: individual crystal

  9. tau jets at L3 1. Tracks are reconstructed with 3 pixel layers only within a cone given by L2.0 jet axis. 2. Isolation cuts: tracks in a big cone (0.3-0.4) vs. a small cone (~0,1), PT(tr)>1-2GeV gg->bbA(500GeV) (Nikitenko & Kotlinski : cms116 analysis)

  10. ET=3 GeV pion in 0<|h|<5 E=EC + a x H1 + H2 +HO e/g Et 100 GeV 3.0 GeV 1.0 Et 100 GeV p 0.9 1.5 GeV 0.8 3 h= 0 5 E= 3 7 30 82 227 GeV P= 0 200 400GeV Pion Response: Linearity ECAHL+HCAL: Non compensating calorimeter CMS Simulation 96’H2 Teast Beam Data

  11. Jet Response and Correction #1 (S.Arcelli) Et-eta dependent correction for QCD jets Et(corr)=a + b x ET(rec) + c x ET(rec)2 With pileup No pileup

  12. Dijet Mass Resolution With pileup No pileup W(jj) Top(jjj) Before correction M(bb) in ttH 15% 21% After correction Jet energy correction without: 19% with: 14% CMSJET 15% 16% 22% (S.Arcelli & V.Drollinger) (R.Kinunnen)

  13. MET Out of cone corr. uses weights for jet(30GeV) corr. Corrections Type 1: Jet corr. Type 2: Jet corr. + out of cone corr.

  14. Corrected MET for mSUGURA Jets+MET at low lumi s Mean offset

  15. Higgs mass in bbA, A2t2j (A.Nikitenko) before correction after correction

  16. Jet correction method #2 Optimized weights by #2 0.0<h<0.4 Jet Corr. #1 a x (EC+HC) - corr. for jet energy scale - a depends on jet(Et,h) Jet Corr. #2 a x EC + b x H1 + g x H2 - optimize jet resolution (and jet energy scale) - a, b, g depends on jet(Et,h) (A.Oulianov)

  17. Jet Correction method #2

  18. Correction method #3a(single pion) (V.Genchev) Method #1 Method #3 i : longitudinal segmenation Minimize with cmsim. resolution linearity 10% (EREC-EIN)/EIN 30% 5% (127+3)% 0% 20% 3% #3 (open) -5% 10% #1 (118+3)% -10% 0% 1 10 100 1000 (GeV) 1 10 100 1000 (GeV) Linearity is restored to 3% in 10-1000GeV for single pion!

  19. Correction Method #3b(single pion) (D.Green) 300 linearity reco 200 (e/h)HCAL~1.39(NIM paper) To find e/h for ECAL, measure e/pi at different energies for showers where there is a substantial energy (> 30% of the beam energy) in ECAL. (e/h)ECAL~1.60 100 beam 0 0 100 200 300 (GeV) resolution 20% s/E Linearity is restored to a few %. The resolution is Gaussian to a high level of accuracy with ~ NO constant term and a 120% stochastic coefficient 10% 5% 10 100 300 (GeV) Next: identify em cluster and had cluster in jet using transverse shower shape (in crystals) and reco-ed tracks and apply this to had cluster.

  20. 0.5GeV 1.0GeV Effect of Thresholdon low ET jet and MET Jets 35<ET(gen)<45geV MET (A.Krokhotine) (S.Nikitenko) Lower threshold is better! Electronics noise and occupancy define the threshold. >> aim at 0.5GeV/tower @ 10E34

  21. Front end electronics simulation (S.Abdoullin) Updated recently E = S (Signal buckets)i – S(pre buckets)j/n Electronics noise 200MeV/25nsec/ch  500MeV/(3+3) buckets/ch  Looking for better method for energy calculation

  22. Algorithm for L1 through Offline (1) • L1 – calorimeter only (coarse segmentation) • Resolution improvement • Equalize calorimeter response with simple correction • a x (EC+HC), a depends on jet(ET,h) • a x EC + b x HC, a,b depends on jet(ET,h) • Fake Jets/Pileup jets rejection • Threshold cut on a central tower in jets (seed cut) • L2 – calorimeter only (fine segmentation) • Resolution improvement • Better energy extraction from ADC counts • Em/had cluster separation using transverse shower shape in crystals • Fake jet/Pileup jet rejection • Use of transverse shower shape

  23. Algorithm for L1 through Offline (2) • L3 – calorimeter plus pixel • Resolution improvement • Pileup energy subtraction • Estimation of energy flow from pileup events using pixel hits/tracks. • Fake jets/Pileup jets rejection • Vertex information and jet pointing using pixel hits/tracks. • Offline – calorimeter plus fully reco-ed tracks • Resolution improvement • Fake jets/Pileup jets rejection •  Jet and MET will be reconstructed with Tracks, EM clusters and HAD clusters. •  All tracks down to ET~ 700MeV have to be reconstructed at 10E34! • Physics correction – e.g. correction for IFR/FSR. •  In-situ calibration!

  24. Long way to go, but promising…

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