Single Top Polarization for MadGraph s-channel sample

1. Single Top s-channel

2. Optimal basis, theory

3. Madevent

1. The generated sample

MadGraph process: pp>tb~, QCD=99, QED=99, Model sm.
Chosen decay: t -> b ve e+

pidschannel.jpg

2. The used macro

{
// Load shared library
  gSystem->Load("../ExRootAnalysis/ExRootAnalysis/lib/libExRootAnalysis.so");
  gSystem->Load("libPhysics");

// Create chain of root trees
  TChain chain("LHEF");
  chain.Add("pptbbar_unweighted_events.root");
  
// Create object of class ExRootTreeReader
  ExRootTreeReader *treeReader = new ExRootTreeReader(&chain);
  Long64_t numberOfEntries = treeReader->GetEntries();
  
// Get pointers to branches used in this analysis
  TClonesArray *branchParticle = treeReader->UseBranch("Particle");
   
// Book histograms
  TCanvas *MyC = new TCanvas("MyC","Test",1);
  gStyle->SetOptStat(0);
  TH1 *histCos = new TH1F("Cos", "s-Channel: Cos(Phi), Optimal Basis", 100, -1, 1);
  
  histCos->GetXaxis()->SetTitle("Cos(Phi)");
  histCos->GetXaxis()->SetLabelSize(0.05);
  histCos->GetYaxis()->SetLabelSize(0.05);
  histCos->GetXaxis()->SetTitleSize(0.05);
  histCos->SetMinimum(0);

// Loop over all events
  for(Int_t entry = 0; entry < numberOfEntries; ++entry) {
 
// Load selected branches with data from specified event
    treeReader->ReadEntry(entry);
    
    TLorentzVector vec1;
    TLorentzVector vec2;
    TLorentzVector vec3;
    TLorentzVector vec4;
    
    if(branchParticle->GetEntries() > 0) {
  
// Loop
               for (int i=0;i<7;i++) {
      TRootLHEFParticle *particle = (TRootLHEFParticle*) branchParticle->At(i);

      if(particle->PID==6){
    vec1.SetPtEtaPhiE(particle->PT, particle->Eta, particle->Phi, particle->E);
    }
      else if(particle->PID==-11){
    vec2.SetPtEtaPhiE(particle->PT, particle->Eta, particle->Phi, particle->E);
   }
      else if(particle->PID==-1){
    vec3.SetPtEtaPhiE(particle->PT, particle->Eta, particle->Phi, particle->E);
   }
   }
   
    TVector3 boost1 = -(vec1)->BoostVector();
    vec2->Boost(boost1);
    vec3->Boost(boost1);
    TVector3 p = vec2.Vect();
    TVector3 q = vec3.Vect();
    Double_t a = p.Angle(q);
    Double_t  b = TMath::Cos(a);
    
    histCos->Fill(b);
            }
  }

  // Show resulting histograms
    histCos->Draw();
}

3. The result

schanneloptimalfit.jpg

4. ONETOP result

schanneltevatronpaper.jpg

5. References

The madgraph website: http://madgraph.hep.uiuc.edu/ -- SarahHeim - 08 Apr 2008
Topic attachments
I Attachment Action Size Date Who Comment
pidschannel.jpgjpg pidschannel.jpg manage 21.5 K 08 Apr 2008 - 22:47 SarahHeim  
schanneloptimalfit.jpgjpg schanneloptimalfit.jpg manage 23.3 K 08 Apr 2008 - 23:08 SarahHeim  
schanneltevatronpaper.jpgjpg schanneltevatronpaper.jpg manage 19.0 K 08 Apr 2008 - 23:10 SarahHeim  
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Topic revision: r19 - 08 Apr 2008, SarahHeim
 

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