VBF background analysis

Some useful links

Tag by pT

Tag jets are, in this case, are the two jets in the event passing all selection cuts that have the largest pT.

Datasets

Dataset name Initial Nevt (106) Final Nevt (103) Integrated luminosity (nb-1) Cross-section (nb)
Data        
/JetMET/Run2010A-Sep17ReReco_v2/RECO 2.41 1.293 3100 ---
MC        
/QCD_Pt_15to30_Tune1_7TeV_pythia8/Fall10-START38_V12-v1/GEN-SIM-RECO 1.097 --- 1.41 780000
/QCD_Pt_30to50_Tune1_7TeV_pythia8/Fall10-START38_V12-v1/GEN-SIM-RECO 1.10 --- 21.87 50300
/QCD_Pt_50to80_Tune1_7TeV_pythia8/Fall10-START38_V12-v1/GEN-SIM-RECO 1.09 --- 180.8 6030
/QCD_Pt_15to30_Tune1_7TeV_pythia6/Fall10-START38_V12-v1/GEN-SIM-RECO 5.45 --- 6.68 815900
/QCD_Pt_30to50_Tune1_7TeV_pythia6/Fall10-START38_V12-v1/GEN-SIM-RECO 3.26 --- 61.37 53120
/QCD_Pt_50to80_Tune1_7TeV_pythia6/Fall10-START38_V12-v1/GEN-SIM-RECO 3.19 --- 501.8 6360

Accepted events

In this case the HLT_Jet30U is selected with an integrated luminosity for the sample is 3.1/pb.

Selection Cut No. of accepted events
Initial number of events after preselection: 3105866
Pass HLT selection 134464
One and only one primary vertex: 56963
Vertex displacement in z < 15 cm: 56954
Vertex ndof >= 4: 56928
At least two jets with pT > 25 GeV:  
Leading pT jets with abs(Δη) < 4.0:  

In addition to these selection cuts, it is requred that jets in the region -2.4 < η < 2.4 pass the following cuts:

  • At least 2 constituents

  • Charged hadronic fraction > 0

  • Charged EM fraction < 1

  • Total neutral fraction < 0.9

Otherwise, we only require they pass the pT requirement.

Basic distributions for 'tagged' jets

Jet1Pt.png

Jet1Phi.png

Jet1Eta.png

Jet2Pt.png

Jet2Phi.png

Jet2Eta.png

Dijet quantities

deltaEta.png

deltaPhi.png

dijetMass.png

Inner jet quantities

To avoid confusion with central jets, I call jets inside the eta region bound by the two tagged jets inner jets. The following plots are inclusive.

InnerMult.png

InnerPt.png

InnerPhi.png

InnerEta.png

InnerZep.png

InnerNormZep.png

InnerZepPrime.png

InnerEFlow.png

MultVsDeltaEta.png

ptHat

ptHat.png

Tag by η

For this selection we choose the two tagged jets to be the two jets with the largest value of Δη.

Datasets

Dataset name Initial Nevt (106) Final Nevt (103) Integrated luminosity (nb-1) Cross-section (nb)
/JetMET/Run2010A-Sep17ReReco_v2/RECO 2.41 1.293 3100 ---
/QCD_Pt_15to30_Tune1_7TeV_pythia8/Fall10-START38_V12-v1/GEN-SIM-RECO 1.097   1.41 780000
/QCD_Pt_30to50_Tune1_7TeV_pythia8/Fall10-START38_V12-v1/GEN-SIM-RECO 1.10   21.87 50300
/QCD_Pt_50to80_Tune1_7TeV_pythia8/Fall10-START38_V12-v1/GEN-SIM-RECO 1.09   180.8 6030

Accepted events

In this case the HLT_Jet30U is selected with an integrated luminosity for the sample is 3.1/pb.

Selection CutSorted descending No. of accepted events
Vertex ndof >= 4:  
Vertex displacement in z < 15 cm:  
Two tagged jets with pT > 25 GeV and abs(Δη) < 4.0:  
Pass HLT selection  
One and only one primary vertex:  
Initial number of events after preselection:  
At least one jet with abs(eta) > 2.0 & pT > 25 GeV:  

In addition to these selection cuts, it is requred that jets in the region -2.4 < η < 2.4 pass the following cuts:

  • At least 2 constituents

  • Charged hadronic fraction > 0

  • Charged EM fraction < 1

  • Total neutral fraction < 0.9

Otherwise, we only require they pass the pT requirement.

Basic distributions for 'tagged' jets

Jet1Pt.png

Jet1Phi.png

Jet1Eta.png

Jet2Pt.png

Jet2Phi.png

Jet2Eta.png

Dijet quantities

deltaEta.png

deltaPhi.png

dijetMass.png

Inner jet quantities

To avoid confusion with central jets, I call jets inside the eta region bound by the two tagged jets inner jets. The following plots are inclusive.

InnerMult.png

InnerPt.png

InnerPhi.png

InnerEta.png

InnerZep.png

InnerNormZep.png

InnerZepPrime.png

InnerEFlow.png

MultVsDeltaEta.png

ptHat

ptHat.png

Original selection

There is no trigger selection on this sample. The integrated luminosity is 3.1/pb.

Selection Cut No. of accepted events
Initial number of events: 3105866
One and only one primary vertex: 588685
Vertex displacement in z < 15 cm: 579057
Vertex ndof >= 4: 578850
At least one forward jet with p_T > 30 GeV: 125700
An additional central jet with p_T > 30 GeV 78292
Two back-to-back forward jets with p_T > 30 GeV: 12127

One forward jet case

First, I consider the case that you have only one forward jet. The requirements on this jet are:

  • |η| > 2.6
  • pT > 30 GeV

Because this jet is in HF, I am not currently applying any jet ID cuts, but will once we determine appropriate values. If one forward jet is found, I then look for the highest pT central jet. The requirements on this jet are:

  • pT > 30 GeV
  • Nconstituents > 1
  • Charged hadronic fraction > 0
  • Neutral hadronic fraction < 1
  • Neutral EM fraction < 1

Basic distributions for 'tagged' jets

cntrMult_1fwd.png

Jet1Pt_1fwd.png

Jet1Phi_1fwd.png

Jet1Eta_1fwd.png

Jet2Pt_1fwd.png

Jet2Phi_1fwd.png

Jet2Eta_1fwd.png

Dijet quantities

deltaEta_1fwd.png

deltaPhi_1fwd.png

dijetMass_1fwd.png

Inner jet quantities

To avoid confusion with central jets, I call jets inside the eta region bound by the two tagged jets inner jets. The following plots are inclusive.

InnerMultPt_1fwd.png

InnerPt_1fwd.png

InnerPhi_1fwd.png

InnerEta_1fwd.png

InnerZep_1fwd.png

Two forward jets

The same cuts are applied in this case except there are two jets in the forward region of the detector. The two forward jets are required to be approximately back-to-back in η. Only the two leading pT forward jets are considered at the moment.

Basic distributions for 'tagged' jets

jet1Pt_2fwd.png

jet1Phi_2fwd.png

jet1Eta_2fwd.png

jet2Pt_2fwd.png

jet2Phi_2fwd.png

jet2Eta_2fwd.png

Dijet quantities

deltaEta_2fwd.png

deltaPhi_2fwd.png

dijetMass_2fwd.png

Inner jet quantities

To avoid confusion with central jets, I call jets inside the eta region bound by the two tagged jets inner jets.

centralJetMult_2fwd.png

innerPt_2fwd.png

innerPhi_2fwd.png

innerEta_2fwd.png

innerZep_2fwd.png

-- NateOdell - 23-Nov-2010


This topic: Main > TWikiUsers > NateOdell > VBFqcdBG
Topic revision: r10 - 2010-12-02 - NateOdell
 
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