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I.Tsukerman ( ITEP, Moscow) Jet/MET WG meeting , clustered week, CERN, September 29,2009

I.Tsukerman ( ITEP, Moscow) Jet/MET WG meeting , clustered week, CERN, September 29,2009. Performances of SISCone, kt and antikt H1 C4Topo jets in VBF H production Thanks to: P.-A. Delsart, D. Rousseau, R. Seuster Event samples and reconstruction algorithms Multiplicities and jet kinematics

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I.Tsukerman ( ITEP, Moscow) Jet/MET WG meeting , clustered week, CERN, September 29,2009

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  1. I.Tsukerman ( ITEP, Moscow) Jet/MET WG meeting, clustered week, CERN, September 29,2009 • Performances of SISCone, kt and antikt H1 C4Topo jets in VBF H production • Thanks to: P.-A. Delsart, D. Rousseau, R. Seuster • Event samples and reconstruction algorithms • Multiplicities and jet kinematics • Et–bias, resolution; efficiencies and impurities • Conclusion and provisional plans

  2. Motivation Jet/MET WG suggested to HWG to look at jets from SISCone and antikt algorithms long time ago Tools exist both at ESD and AOD/AANT level, thanks to P.-A. MC08: only 10% ESD produced  mostly AOD analysis Results for local hadronic calibration were presented this January: http://indico.cern.ch/getFile.py/access?contribId=1&resId=1&materialId=slides&confId=48206 However “H1-based” Topo jets cannot be obtained from AOD So ESD’s for VBF Higgs production were used Sorry for some delay with this study!

  3. Samples and reconstructed algorithms • Dataset 105335, 3K VBF Herwig VBF Hinvisible (m(H)=130GeV) events at 10TeV • Dataset 109011, 5K VBF Sherpa VBF Hinvisible (m(H)=130GeV) events at 10TeV • mc08.109011.SherpaHtoinvisibleMH130.recon.e361_s462_r635 • mc08.105335.HerwigVBFH130invisible.recon.e361_s462_r635 • ATLAS-GEO-02-01-00, QGSP_BERT physics list, G4.9 • Initially 4 jet “collections” only (H1 C4Tower,C4Topo,C4Truth,C7Tower) • Run on projective towers (or Topoclusters); limitations: Et>7GeV, |h|<5; • Here also: H1 SISC4Topo, Kt4Topo, AntiKt4Topo jet collections • After modified esdtocbnt.py: NTuples at /castor/cern.ch/user/z/zuckerma/mc08/ • Thanks to David, Pierre-Antoine and Rolf for help to prepare joboptions • Private algorithm: matching true-reconstructed jets, ROOT, DR0=0.15 • updated for 14.5.0 AANT with new jet collections • Jet properties: Jet/EtMiss WG • Jet tagging, veto and VBF Higgs: Higgs WG

  4. Jet multiplicities in VBF H events(m(H)=130 GeV)at Et>20 GeV for different collections 2.7<|h|<5 forward |h|<5 2.7<|h|<5 forward |h|<5 Multiplicities are very similar for different algorithms

  5. Some definitions: reminder Reconstruction efficiency: for TRUE jets e(Et, h, DR0) = N(matched) / N(all) Impurity: for RECONSTRUCTED jets imp(Et, h, DR0) = M(unmatched) / M(all) Definitions correspond to Atlas Technical Paper Bias(Et) = <(Et(reco)-Et(true))/Et(true)> (gaussian) Resolution(Et) = s((Et(reco)- Et(true)) / Et(true))

  6. Correspondence true-reco jets for cone 0.4 collections at Et>20 GeV, here DR<0.5 Dh Dh central forward DR DR central forward Performances are comparable, a bit worse for Kt4

  7. Et-bias and resolution for VBF Higgs events for central jets with Et>20 GeV C4Topo Kt4Topo AntiKt4 Topo SISCone4 Topo -2% bias and larger left tail for Kt4; other things similar and ok

  8. Et-bias and resolution for VBF Higgs events for forward jets with Et>20 GeV C4Topo Kt4Topo AntiKt4 Topo SISCone4 Topo -9% bias for Kt4; other things similar and ok

  9. Et-bias vs Et and h for VBF Higgs events LC: ~ok in central region, problems in EC and FCal forward central Et>10GeV Et>20GeV Problems with calibration for Kt4, other things similar and ok

  10. Jet reco e vs Et and h for VBF Higgs events forward central Et>20GeV Et>10GeV A bit worse efficiency for kt4 jets, other cases similar

  11. Jet reco impurity vs Et /h for VBF Higgs events central forward Et>10GeV Et>20GeV Impurities are a bit worse for Kt4

  12. Conclusion and short-term plans • H1 SISCone4Topo, Kt4Topo, antikt4Topo considered • Kt4 has problems with calibration and worse performance • New algs have comparable performance with H1 C4Topo • Biases, resolutions, efficiencies, impurities, matching are reasonable • To be done: • - study of similar issues with pile-up (problem: limited statistics) • - relook at H1 and LC-based jets in release 15

  13. Jet multiplicities in VBF H events(m(H)=130 GeV)at Et>10 GeV for different collections 2.7<|h|<5 forward |h|<5 Multiplicities are slightly different

  14. Correspondence between true and reco jets for cone 0.4 collections at Et>10 GeV Dh Dh forward central DR DR central forward Performances of algorithms are comparable

  15. Et-bias and resolution for VBF Higgs events for central jet Et>10 GeV Kt4 Topo C4Topo AntiKt4 Topo SISC4 Topo -3% bias for Kt4 ; resolutions similar

  16. Et-bias and resolution for VBF Higgs events for forward jet Et>10 GeV C4Topo Kt4Topo AntiKt4 Topo SISC4 Topo -10% bias for Kt4; resolutions similar

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