Goal      : To separate small sample of W leptonic decays from the dominant QCD background
Concept : Use the kinematical and topological differences in 2 classes of events . 
                       
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1) Trigger;  L2BW
          a)  level 0: BHT3 threshold of ET > 7:3 GeV in a single BEMC tower
          b)   level 2 : A seed tower with ET > 5 GeV
          c)   level 2 : 2 X  2 tower cluster including the  seed tower with ET > 12 GeV

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2) Primary Vertex;      PPV ( at least 2 high quality primary matched track candidates originating from the same Z location or a single primary track with pT > 10 GeV/c matched to the  red tower)

            a) vertices with |Vz|< 100 cm

            b)  rank > 0   

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3) isolated Candidate  lepton selection in Barrel

     i) Primary track
                      a) Primary track "flag" = 301

                      b) Primary track nFitPoints > 15

                      c) Fraction of track hits out of possible track hits > 0.51
                      d)Radius of the track hit nearest to the beamline < 90 cm

                      e)Radius of the track hit farthest from the beamline > 160 cm

                      f) primary track have pT > 10 GeV/c

  
   ii) Primary tracks and cluster Matching
                     a) E^eT > 14 GeV
                     b) The magnitude of the 2D distance between the energy log-weighted centroid of the tower cluster and the extrapolated track is < 7 cm

  iii) Isolating leptons
                a) E^T_(2x2) / E^T_(4x4)  > 95%

 
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5) Charge sign reconstruction

|Q*ET/PT| >  0.4

|Q*ET/PT| <  1.8

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slides

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jet finading parameters;

// Set analysis cuts for 12-point branch

StAnaPars* anapars12 = new StAnaPars;

anapars12->useTpc = true;

anapars12->useBemc = true;

anapars12->useEemc = true;

anapars12->setTowerEnergyCorrection(new\

StjTowerEnergyCorrectionForTracksFraction(1.00));

// TPC cuts

anapars12->addTpcCut(new StjTrackCutFlag(0));

anapars12->addTpcCut(new StjTrackCutNHits(12));

anapars12->addTpcCut(new StjTrackCutPossibleHitRatio(0.51));

anapars12->addTpcCut(new StjTrackCutDca(3));

anapars12->addTpcCut(new StjTrackCutTdcaPtDependent);

anapars12->addTpcCut(new StjTrackCutPt(0.2,200));

anapars12->addTpcCut(new StjTrackCutEta(-2.5,2.5));

anapars12->addTpcCut(new StjTrackCutLastPoint(125));

// BEMC cuts

anapars12->addBemcCut(new StjTowerEnergyCutBemcStatus(1));

anapars12->addBemcCut(new StjTowerEnergyCutAdc(4,3));

anapars12->addBemcCut(new StjTowerEnergyCutEt(0.2));

// EEMC cuts

anapars12->addEemcCut(new StjTowerEnergyCutBemcStatus(1));

anapars12->addEemcCut(new StjTowerEnergyCutAdc(4,3));

anapars12->addEemcCut(new StjTowerEnergyCutEt(0.2));

// Jet cuts

anapars12->addJetCut(new StProtoJetCutPt(3.5,200));

anapars12->addJetCut(new StProtoJetCutEta(-100,100));

// Set anti-kt R=0.6 parameters

StFastJetPars* AntiKtR060Pars = new StFastJetPars;