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First pass for W+jets backgroung estimate in p14

First pass for W+jets backgroung estimate in p14. Denis Gel é, Daniel Bloch, Benoit Clément, Sébastien Greder, Isabelle Ripp-Baudot (IReS Strasbourg). D ata samples Taggability B tagging efficiency and scale factor SF(b) Mistag and scale factors SF(hf) and SF(ll)

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First pass for W+jets backgroung estimate in p14

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  1. First pass forW+jets backgroung estimate in p14 Denis Gelé, Daniel Bloch, Benoit Clément, Sébastien Greder, Isabelle Ripp-Baudot (IReS Strasbourg) • Data samples • Taggability • B tagging efficiency and scale factor SF(b) • Mistag and scale factors SF(hf) and SF(ll) • Tagging event probability • Conclusion D. Gelé (IReS Strasbourg)

  2. Data samples • EM sample p14: About 1M Top-tree p14.03.00,01,02 events ( >= 1 loose EM, Pt(e),Pt(jet)>15 GeV, eta(e),eta(jet)<2.5 ). Used to derive taggability. • muon-in-jet: p14.03 root-tree events ( jets with a medium muon of pt>4 GeV and R<0.5 ). Used to compute JLIP tagging effciency in the data. • “p14.02” MC(LP03 samples) :Wbb, Wbbj, Wbbjj (for JLIP-tagging efficiency and tagging scale factor), Wc, Wcc, Wccj, Wccjj, Wcjj, Wcj, Wcjj (for JLIP-tagging efficiency). P14.03 Qcd 40,80 GeV for mistag scale factors. D. Gelé (IReS Strasbourg)

  3. Taggability Sample and cuts: EM p14 sample, no constraint on EM object, no trigger signal. Ariels’ PV (one pass, highest multiplicity), cuts:NbTracks>=3,|Z|<60cm. Top taggability definition (>=2 trks, Pt>0.5 GeV, ²<3, >=3 SMT hits or 2 SMT hits in 2 inner layers, dcaz<1cm) Taggability ~ 70% D. Gelé (IReS Strasbourg)

  4. B-tagging efficiency in p14.03 data The b-tagging efficiency has been computed with top taggability definition and with p13 updated JLIP tagger (parametrization of negative significance resolution functions in 29 categories according to Pt,  and ² tracks). Sample: muon-in-jet p14.03, Pt()>4 GeV. System8 method is used here for a JLIP probability cut of 1% : b-tagging effciency ~48% (Xchecks with fits on PtRel () distributions done, see B-id meetings). D. Gelé (IReS Strasbourg)

  5. B/C tagging efficiency in WbX, WcX p14 Monte-Carlo b jets c jets Scale factor SF(b) is defined as the ratio of semileptonic b-tagging efficiency in data on the MC corresponding one: SF(b) = (b,data)/ (b,mc) SF(b) dependance on (Pt,) jet We assume SF(c)=SF(b) D. Gelé (IReS Strasbourg)

  6. Mistag and scale factors SF(hf) and SF(ll) SF(hf)=ratio of neg. tag. efficiency for light jets and the one inclusive over flavors. SF(ll)=ratio of pos. to neg. tag. efficiencies for light jets. (Both extracted from Qcd40+80 Monte-Carlo). <SF(hf)>=0.70+-0.02 (stat) <SF(ll)>=1.44+-0.04(stat) D. Gelé (IReS Strasbourg)

  7. Mistag and scale factors SF(hf) and SF(ll) Total scale factor: SF(hf)*SF(ll) =1.00+-0.04 (stat) ( dependance) 1% JLIP probability cut D. Gelé (IReS Strasbourg)

  8. Mistag for light jets Mistag for light jets is obtained from JLIP negative tagging efficiency in data (jettrigger or emqcd samples) corrected with previous global scale factor. D. Gelé (IReS Strasbourg)

  9. Event tagging probability in p14 (preliminary) We compute the event tagging probability PTagEvt according to: PTagEvt = 1 - (1 –Pjet(Pt,,flavour)) with Pjet(Pt,,flavour) = Ptagg,data (Pt,) (Pt,,flavour) Ptagg,data (Pt,) : Taggability (determined from data, assume to be flavour independent) (Pt,,flavour) : Jet tagging efficiency (calibrated with data, ProbaJLIPCut=1%) No trigger, parton-matching Wbb Wc Wj D. Gelé (IReS Strasbourg)

  10. Summary • Fisrt pass with p14 seems to be coherent. • Still (much) work to perform (new MC with MichelAngelo TopAnalyze version, tagging with certified JLIP, new ID Object, jet-parton matching etc ..... • Benoit will attend the Single top Workshop (presentation/update of System8 method for background separation). D. Gelé (IReS Strasbourg)

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