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Status Report: H  ZZ (*)  mm qq(bb) via VBF

Marco De Mattia, Tommaso Dorigo, Mia Tosi , Pietro Vischia Universita’ degli Studi di Padova & INFN. Status Report: H  ZZ (*)  mm qq(bb) via VBF. studies @7TeV pre-selection tag-jets selection  BDT high-mass Higgs selection leptonic Z selection

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Status Report: H  ZZ (*)  mm qq(bb) via VBF

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  1. Marco De Mattia, Tommaso Dorigo, Mia Tosi, Pietro Vischia Universita’ degli Studi di Padova & INFN Status Report:HZZ(*)mmqq(bb) via VBF • studies @7TeV • pre-selection • tag-jets selection  BDT • high-mass Higgs selection • leptonic Z selection • hadronic Z selection  b-tagging • conclusion&plans October 18th, 2010

  2. transversl view jetZ2 muon2 jetT1 jetT2 jetZ1 muon1 longitudinal view analysis strategy 0-order pre-selection [physics objects and topology] tag-jets [signal kinematics by BDT] • high-mass Higgs • both Zs are • on-shell • boosted • look for • a Zmm[m kinematics] • a Zbbbar[b-tag+jet kinematics] • low-mass Higgs • one Z is on-shell and @rest • while, the other is off-shell • look for • an on-shellZmm[m kinematics] • an off-shellZbbbar[b-tag]

  3. samples Spring10 bkg samples (official) • Z+jets • - SHERPA [M10to50 + M50to10000] • [MADGRAPH one has cuts @GEN] • Zbb • - MADGRAPH VQQ • ttbar • - MADGRAPH TTjets • VV • - PYTHIA6 ZZincl • - PYTHIA6 WZincl • - MADGRAPH VVJets • produced in CMSSW_3_5_6 • generated @s=7TeV w/o pile-up • fully simulated w/ IDEAL geometry • ntplized number of expected events in Lint=1fb-1 is ~0 !!!  [integrated luminosity in 2010+2011] • signal samples • VBF [PYTHIA6] • 130,150,500 GeV/c2 • +200,300 GeV/c2 [private] • only limits on the Higgs mass

  4. pre-selections • @ 0-order ask for • at least 2 muons w/ • pT  15 (10) GeV/c • q1 q2 < 0 • mmm> 12.GeV/c2 • at least 4 (PF)jets w/ • pT  15 (30) GeV/c • in the barrel (forward) region

  5. tag-jets selection: BDT known the right combination [jet-parton matching w/in DR0.5] now, it is possible to • exploit the kinematics and choose the tag-jets pair • applying a multivariate method [BDT] trained to distinguish between two different categories: • signal-like events: • all matched jets to tag-partons • background-like events: • wrong [random] choice h1xh2 |hmax| Dhjj mjj

  6. tag-jets selection: BDT known the right combination [jet-parton matching w/in DR0.5] now, it is possible to • exploit the kinematics and choose the tag-jets pair • applying a multivariate method [BDT] trained to distinguish between two different categories: • signal-like events: • all matched jets to tag-partons • background-like events: • wrong [random] choice BDT output @70% of signal efficiency mH=130GeV/c2 mH=500GeV/c2

  7. tag-jets selection: BDT cut [mH=500GeV/c2] signal efficiency (%)

  8. Zmm candidates selection L=30fb-1 L=30fb-1 L=30fb-1 L=30fb-1

  9. Zmm selection: mass window optimization after pre-selection+BDT after pre-selection+BDT+2b-tags L=30fb-1 L=30fb-1 • after (2)b-tag cut, • no sufficient statistics for optimizing the Zmm mass window  • scaledistributions before this cut to statistics after it

  10. Zmm selection: mass window optimization scaled to after b-tag cut L=30fb-1 [83;99]

  11. Zmm selection: mass window optimization scaled to after b-tag cut L=30fb-1 [83;99]

  12. b-tagging CMS develops several b-tagging algorithms… .. but, WHICH ONE TO CHOOSE ?!? events w/ #b-quarks ≥ 1 • considering as discriminator cut [for each algo] • the value|eb-tagging 60% [on signal], • look@ different performance in terms of S/N, • paying attention on the b-jet multiplicity ≥ Nb-tag Combined Secondary Vertex ≥ Nb-tag

  13. b-tagging efficiency all events ≥ Nb-tag

  14. Zqq selection L=30fb-1

  15. Zqq mass reconstruction L=30fb-1

  16. 4-bodies mass reconstruction L=30fb-1

  17. 4-bodies mass reconstruction requesting (2)b-tag L=30fb-1

  18. addendum • the search of • a high-mass Higgs boson into ZZ* • in its semi-leptonic final state w/ ms • pass through • an almost standard Z->mm extraction • looking @ events • w/ high multiplicity jets [>=4] • w/ b-tagged jets -> tracker ;) • w/o MET -> commissioning PAS [JINST]

  19. BACKUP

  20. ntuplizer simpleNtple • event and trigger • genPartciles • GenJets • GenMet • CaloJets • PFJets • globalMuons • CaloMet • GfsElectron • PrimaryVertex • produce light-ntuple • w/ the most complete set of information • event and trigger • MCTruth • Muons • Jets [different clustering algorithms (AK,IC)] both Calo and PF • Electrons • MET • Vertices

  21. tag-jets selection: BDT cut [mH=130GeV/c2]

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