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NA-ATLAS mtg

NA-ATLAS mtg. Experience from the Tevatron – Chlebana FNAL. Experience from the Tevatron – Chlebana FNAL. Experience from the Tevatron – Chlebana FNAL. Experience from the Tevatron – Chlebana FNAL. Rate of leading jet in Z ee, + jets after central jet veto. Jet Tagging and Jet Veto.

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NA-ATLAS mtg

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  1. NA-ATLAS mtg

  2. Experience from the Tevatron – Chlebana FNAL

  3. Experience from the Tevatron – Chlebana FNAL

  4. Experience from the Tevatron – Chlebana FNAL

  5. Experience from the Tevatron – Chlebana FNAL

  6. Rate of leading jet in Zee, + jets after central jet veto Jet Tagging and Jet Veto • Z ee, + jets gives a large statistics sample for the calibration of jets all the way to the forward region • Signalextraction does not depend directly on jet energy scale. Enough to have 5% (10%) energy scale uncertainty for central (forward) jets • Study central jet veto with same sample See W.Quayle’s talk Mellado – Performance requirements

  7. Huston

  8. Huston

  9. Huston

  10. Seuster Jet/Et-miss

  11. Narain – b-tagging Technique • Quite a few Taggers are available: • Impact Parameter based taggers (IP2D, IP3D) • Secondary vertex reconstruction based • Provide discrimination based on a comparison between two hypotheses: • likelihood for a jet to originate from a b-quark(b) OR a light-quark/gluon (u) • For each discriminating variable x in a tagger, build calibration functions for the two hypotheses • Pb(x) and Pu(x) • The final discriminating variable (jet level) : W = x ln(Pb(x) /Pu(x)) Large W ~ high probability that the jet originates from a b quark

  12. J.-B. de Vivie, V.Kostyukhin A. Rozanov, L Vacavant Performance ( ) SV1+IP3D IP3D IP2D Lifetime2D lhSig • H events • Model u-jets using ttjj • release 10.0.1 • High eff crucial: εb4 as a function of pTand || @ 60%efficiency

  13. Planned Improvements • goal to reach εb=70 % with Ru=100 • A few planned improvements: (Some are already in 11.X.0 or will be in release 12) • combine space and soft leptons in jets • K0 and Λ0 impact parameters, no direct tracks IP • New tracking • track quality classification • multiple secondary vertices • shared/ambiguous hits, kill interactions • +…

  14. L Vacavant Software Changes • Transition from JetTag (‘previous’) and ParticleJet (‘new’) • A single collection for jets (calo+btagging information) • In the 11.X.0 branch • Implies that ‘previous’ AOD not readable w/ ‘new’ release. • For ‘previous’ btagging: • All releases 11.0.X are OK • Recommended: 11.0.4(,1,2) • For ‘new’ btagging: • 11.4.0 not recommended • 11.5.0: • Will be useable for b-tagging, including soft lepton taggers • 12.0.0: scheduled for 1st half of May… • possible to run ‘new’ btagging in 11.0.4(1,2)

  15. Beam xing angle ~ 1 GeV Half-angle 143mrad – vertical (CMS same angle, horizontal)

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