-- NikolozSkhirtladze - 11-Oct

Fake Rate

1. Samples used

MC W+Jets: /WJets-madgraph/Spring10-START3X_V26_S09-v1/GEN-SIM-RECO 1e+07 events

MC QCD:

  1. /QCD_Pt100to250-madgraph/Spring10-START3X_V26_S09-v2/GEN-SIM-RECO
  2. /QCD_Pt250to500-madgraph/Spring10-START3X_V26_S09-v2/GEN-SIM-RECO
  3. /QCD_Pt500to1000-madgraph/Spring10-START3X_V26_S09-v2/GEN-SIM-RECO
  4. /QCD_Pt1000toInf-madgraph/Spring10-START3X_V26_S09-v2/GEN-SIM-RECO

Data jet-Triggered (Run: 141956-144114 ): /JetMET/Run2010A-Sep17ReReco_v2/RECO

2. Selections and imposed cuts

For Muons:

  1. Global and Tracker muons
  2. Pt > 5
  3. |Eta| < 2.4
  4. Number of ValidHits > 10
  5. Normalized Chi2 < 10
  6. EcalvetoDep <= 4 GeV
  7. HcalvetoDep <= 6 GeV
  8. RelIso < 0.15 where RelIso = (HcalIso+EcalIso+TrackIso)/Pt
  9. D0B < 0.02 cm

For Electron:

  1. simpleEleId95cIso 5 7
  2. Pt > 10
  3. |Eta| < 2.4
  4. 1.47 < |Eta | < 1.567 exclude
  5. RelIso < 0.15 where RelIso = (HcalIso+EcalIso+TrackIso)/Pt
  6. D0B < 0.02 cm
  7. Charge consistency requirement using CTF,GSF and SuperCluster.

For Tracks:

  1. Track ID: general_Track
  2. Any track with isolation < 10 GeV/c within the cone(eta, phi space) size < 0.3
  3. The same kinematics and quality cuts as for muon:

For Jets:

  1. ID: PFJets
  2. Pt > 30
  3. |Et| < 2.5
  4. No cleaning (w.r.t leptons) applied

3. Definitions of numerator and denominator for FR

Numerator:

  1. For MC W+Jets sample: All muons coming from QCD part and passing the above cuts. Muons coming from W's (W->mu) are removed from the numerator.
  2. For MC QCD mamples: All muons passing the above cuts.
  3. For Data sample: All muons passing the above cuts.

Denominator:

  1. For MC W+Jets sample: All tracks passing the above cuts and isolation. Tracks associated leptons coming from W's (W->mu, e) are removed from the denominator.
  2. For MC QCD mamples: All tracks passing the above cuts and isolation.
  3. For Data sample: All tracks passing the above cuts and isolation.

some details for W+Jets sample: As it was mentioned above, W->mu and track associated with it are removed from numerator and denominator respectively. This is done in the following way.

  1. For muons: First we loop over the Reco muon and try to find the closest Gen level muon coming from W's ( matching within dR(eta, phi) < 0.2 ). if there is such rec muon, it is considered w->mu at Reco level (these muons are kept in the separate container for further analysis ).
  2. For tracks: We loop over A container (mentioned above) and try to find the closest track to it with the matching criteria: dR(eta,phi) < 0.3 and (Pt(track) - Pt(mu))/Pt(track) < 0.5
  3. To clean tracks from tracks associated with W->e is under investigation.

4. Meaning of FR

Knowing the FR as it is defined above, we can find what is the probability that a track gives us a muon (under muon, it is meant all muons coming from QCD part, includes decays-in-flight, punchthrough etc). This method will be used for SUSY analysis to estimate W+Jets background, which is second most important bkc after TTbar. The control sample for that method is jet triggered data ( /JetMET/Run2010A-Sep17ReReco_v2/RECO )

More updates coming.

Topic attachments
I Attachment History Action Size Date Who Comment
PDFpdf ForNik.pdf r1 manage 33.6 K 2010-10-12 - 03:39 NikolozSkhirtladze Plot From the paper to compare with
GIFgif Reproduced_Eta.gif r1 manage 7.0 K 2010-10-12 - 03:38 NikolozSkhirtladze Reproduced Fake rate distribution vs Eta
GIFgif Reproduced_Pt.gif r1 manage 7.0 K 2010-10-12 - 03:39 NikolozSkhirtladze Reproduced Fake rate distribution vs Pt
GIFgif TWiki_Eta_Iso_NoIso_Overlapped.gif r1 manage 9.0 K 2010-10-12 - 03:37 NikolozSkhirtladze Two plots with and without isolations overlapped vs Eta
GIFgif TWiki_Pt_Iso_NoIso_Overlapped.gif r1 manage 8.3 K 2010-10-12 - 03:38 NikolozSkhirtladze Two plots with and without isolations overlapped vs Pt
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Topic revision: r5 - 2010-10-19 - NikolozSkhirtladze
 
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