HLTTauMCProducer.cc

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#include "HLTriggerOffline/Tau/interface/HLTTauMCProducer.h"

using namespace edm;
using namespace std;
using namespace reco;

HLTTauMCProducer::HLTTauMCProducer(const edm::ParameterSet& mc)
{
 
  //One Parameter Set per Collection

  MC_      = mc.getUntrackedParameter<edm::InputTag>("GenParticles");
  ptMinMCTau_ = mc.getUntrackedParameter<double>("ptMinTau",5.);
  ptMinMCMuon_ = mc.getUntrackedParameter<double>("ptMinMuon",2.);
  ptMinMCElectron_ = mc.getUntrackedParameter<double>("ptMinElectron",5.);
  m_PDG_   = mc.getUntrackedParameter<std::vector<int> >("BosonID");
  etaMax = mc.getUntrackedParameter<double>("EtaMax",2.5);

  produces<LorentzVectorCollection>("LeptonicTauLeptons");
  produces<LorentzVectorCollection>("LeptonicTauElectrons");
  produces<LorentzVectorCollection>("LeptonicTauMuons");
  produces<LorentzVectorCollection>("HadronicTauOneProng");
  produces<LorentzVectorCollection>("HadronicTauThreeProng");
  produces<LorentzVectorCollection>("HadronicTauOneAndThreeProng");
  produces<LorentzVectorCollection>("TauOther");
  produces<LorentzVectorCollection>("Neutrina");
  produces<std::vector<int> >("Mothers");

}

HLTTauMCProducer::~HLTTauMCProducer(){ }

void HLTTauMCProducer::produce(edm::Event& iEvent, const edm::EventSetup& iES)
{
  //All the code from HLTTauMCInfo is here :-) 
  
  auto_ptr<LorentzVectorCollection> product_Electrons(new LorentzVectorCollection);
  auto_ptr<LorentzVectorCollection> product_Muons(new LorentzVectorCollection);
  auto_ptr<LorentzVectorCollection> product_Leptons(new LorentzVectorCollection);
  auto_ptr<LorentzVectorCollection> product_OneProng(new LorentzVectorCollection);
  auto_ptr<LorentzVectorCollection> product_ThreeProng(new LorentzVectorCollection);
  auto_ptr<LorentzVectorCollection> product_OneAndThreeProng(new LorentzVectorCollection);
  auto_ptr<LorentzVectorCollection> product_Other(new LorentzVectorCollection);
  auto_ptr<LorentzVectorCollection> product_Neutrina(new LorentzVectorCollection);
  auto_ptr<std::vector<int> > product_Mothers(new std::vector<int>);
  
  edm::Handle<GenParticleCollection> genParticles;
  iEvent.getByLabel(MC_, genParticles);

  GenParticleCollection::const_iterator p = genParticles->begin();
  
  for (;p != genParticles->end(); ++p ) {
    //Check the PDG ID
    bool pdg_ok = true;
    for(size_t pi =0;pi<m_PDG_.size();++pi)
      {
    if(abs((*p).pdgId())== m_PDG_[pi] && abs((*p).status()) == 3 ){
      pdg_ok = true;
      //      cout<<" Bsoson particles: "<< (*p).pdgId()<< " " <<(*p).status() << " "<< pdg_ok<<endl;
    }
      }
    
    // Check if the boson is one of interest and if there is a valid vertex
    if(  pdg_ok )
      {
    product_Mothers->push_back((*p).pdgId());

    std::vector<GenParticle*> decayProducts;
    
    TLorentzVector Boson((*p).px(),(*p).py(),(*p).pz(),(*p).energy());  
    
    for (GenParticle::const_iterator BosonIt=(*p).begin(); BosonIt != (*p).end(); BosonIt++){
      // cout<<" Dparticles: "<< (*BosonIt).pdgId() << " "<< (*BosonIt).status()<<endl;
      
      if (abs((*BosonIt).pdgId()) == 15 && ((*BosonIt).status()==3)) //if it is a Tau and decayed
        {
          decayProducts.clear();      
          //          cout<<" Boson daugther particles: "<< (*BosonIt).pdgId() << " "<< (*BosonIt).status()<< endl;       
          for (GenParticle::const_iterator TauIt = (*BosonIt).begin(); TauIt != (*BosonIt).end(); TauIt++) {
        //  cout<<" Tau daughter particles: "<< (*TauIt).pdgId() << " "<< (*TauIt).status()<<endl;

        if (abs((*TauIt).pdgId()) == 15 && ((*TauIt).status()==2)) //if it is a Tau and decayed
          {         
            decayProducts = getGenStableDecayProducts((reco::GenParticle*) & (*TauIt));  
            //  for (GenParticle::const_iterator TauIt2 = (*TauIt).begin(); TauIt2 != (*TauIt).end(); TauIt2++) {
            //            cout<<" Real Tau particles: "<< (*TauIt2).pdgId() << " "<< (*TauIt2).status()<< " mother: "<< (*TauIt2).mother()->pdgId() << endl;
            // }
          }
          }
          
          
          if ( !decayProducts.empty() )
        {
          
          LorentzVector Visible_Taus(0.,0.,0.,0.);
          LorentzVector TauDecayProduct(0.,0.,0.,0.);
          LorentzVector Neutrino(0.,0.,0.,0.);
          
          int numElectrons      = 0;
          int numMuons          = 0;
          int numChargedPions   = 0;
          int numNeutralPions   = 0;
          int numNeutrinos      = 0;
          int numOtherParticles = 0;
          
          
          for (std::vector<GenParticle*>::iterator pit = decayProducts.begin(); pit != decayProducts.end(); pit++)
            {
              int pdg_id = abs((*pit)->pdgId());
              if (pdg_id == 11) numElectrons++;
              else if (pdg_id == 13) numMuons++;
              else if (pdg_id == 211) numChargedPions++;
              else if (pdg_id == 111) numNeutralPions++;
              else if (pdg_id == 12 || 
                   pdg_id == 14 || 
                   pdg_id == 16) {
            numNeutrinos++;
            if (pdg_id == 16) {
              Neutrino.SetPxPyPzE((*pit)->px(),(*pit)->py(),(*pit)->pz(),(*pit)->energy());
            }
              }
              else if (pdg_id != 22) {
            numOtherParticles++;
              }
              
              if (pdg_id != 12 &&
              pdg_id != 14 && 
              pdg_id != 16){
            TauDecayProduct.SetPxPyPzE((*pit)->px(),(*pit)->py(),(*pit)->pz(),(*pit)->energy());
            Visible_Taus+=TauDecayProduct;
              } 
              //          cout<< "This has to be the same: " << (*pit)->pdgId() << " "<< (*pit)->status()<< " mother: "<< (*pit)->mother()->pdgId() << endl;
            }
          
          int tauDecayMode = kOther;
          
          if ( numOtherParticles == 0 ){
            if ( numElectrons == 1 ){
              //--- tau decays into electrons
              tauDecayMode = kElectron;
            } else if ( numMuons == 1 ){
              //--- tau decays into muons
              tauDecayMode = kMuon;
            } else {
              //--- hadronic tau decays
              switch ( numChargedPions ){
              case 1 : 
            switch ( numNeutralPions ){
            case 0 : 
              tauDecayMode = kOneProng0pi0;
              break;
            case 1 : 
              tauDecayMode = kOneProng1pi0;
              break;
            case 2 : 
              tauDecayMode = kOneProng2pi0;
              break;
            }
            break;
              case 3 : 
            switch ( numNeutralPions ){
            case 0 : 
              tauDecayMode = kThreeProng0pi0;
              break;
            case 1 : 
              tauDecayMode = kThreeProng1pi0;
              break;
            }
            break;
              }         
            }
          }
          
          
          //          cout<< "So we have a: " << tauDecayMode <<endl;
          
          if(tauDecayMode == kElectron)
            {                 
              if((abs(Visible_Taus.eta())<etaMax)&&(Visible_Taus.pt()>ptMinMCElectron_)){
            product_Electrons->push_back(Visible_Taus);
            product_Leptons->push_back(Visible_Taus);
              }
            }
          else if (tauDecayMode == kMuon)
            {
              
              if((abs(Visible_Taus.eta())<etaMax)&&(Visible_Taus.pt()>ptMinMCMuon_)){
            product_Muons->push_back(Visible_Taus);
            product_Leptons->push_back(Visible_Taus);
              }
            }
          else if(tauDecayMode == kOneProng0pi0 || 
              tauDecayMode == kOneProng1pi0 || 
              tauDecayMode == kOneProng2pi0 ) 
            {
              if ((abs(Visible_Taus.eta()) < etaMax) && (Visible_Taus.pt() > ptMinMCTau_)){
            product_OneProng->push_back(Visible_Taus);
            product_OneAndThreeProng->push_back(Visible_Taus);
            product_Neutrina->push_back(Neutrino);
              }
            }
          else if (tauDecayMode == kThreeProng0pi0 || 
               tauDecayMode == kThreeProng1pi0 )
            {
              if((abs(Visible_Taus.eta())<etaMax)&&(Visible_Taus.pt()>ptMinMCTau_))  {
            product_ThreeProng->push_back(Visible_Taus);
            product_OneAndThreeProng->push_back(Visible_Taus);
            product_Neutrina->push_back(Neutrino);
              }                             
            }
          else if (tauDecayMode == kOther)
            {
              if((abs(Visible_Taus.eta())<etaMax)&&(Visible_Taus.pt()>ptMinMCTau_))  {
            product_Other->push_back(Visible_Taus);
              }
            }                              
        }
        }
    }                  
    //  
      }
  }
  iEvent.put(product_Leptons,"LeptonicTauLeptons");
  iEvent.put(product_Electrons,"LeptonicTauElectrons");
  iEvent.put(product_Muons,"LeptonicTauMuons");
  iEvent.put(product_OneProng,"HadronicTauOneProng");
  iEvent.put(product_ThreeProng,"HadronicTauThreeProng");
  iEvent.put(product_OneAndThreeProng,"HadronicTauOneAndThreeProng");
  iEvent.put(product_Other, "TauOther");
  iEvent.put(product_Neutrina,"Neutrina"); 
  iEvent.put(product_Mothers,"Mothers"); 
  
                               
}
// Helper Function

std::vector<reco::GenParticle*> HLTTauMCProducer::getGenStableDecayProducts(const reco::GenParticle* particle)
{
  std::vector<GenParticle*> decayProducts;
  decayProducts.clear();

  //  std::cout << " Are we ever here?: "<< (*particle).numberOfDaughters() << std::endl;
  for ( GenParticle::const_iterator daughter_particle = (*particle).begin();daughter_particle != (*particle).end(); ++daughter_particle ){   

    int pdg_id = abs((*daughter_particle).pdgId());

//    // check if particle is stable
    if ( pdg_id == 11 || pdg_id == 12 || pdg_id == 13 || pdg_id == 14 || pdg_id == 16 ||  pdg_id == 111 || pdg_id == 211 ){
      // stable particle, identified by pdg code
      decayProducts.push_back((reco::GenParticle*) &(* daughter_particle));
    } 
    else {
//      // unstable particle, identified by non-zero decay vertex
      std::vector<GenParticle*> addDecayProducts = getGenStableDecayProducts((reco::GenParticle*) &(*daughter_particle));
      for ( std::vector<GenParticle*>::const_iterator adddaughter_particle = addDecayProducts.begin(); adddaughter_particle != addDecayProducts.end(); ++adddaughter_particle ){
    decayProducts.push_back((*adddaughter_particle));
      }
    }
  }
  return decayProducts;
}