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/*class WValidation
 *  
 *  Class to fill dqm monitor elements from existing EDM file
 *
 *  $Date: 2011/01/24 18:27:40 $
 *  $Revision: 1.4 $
 */
 
#include "Validation/EventGenerator/interface/WValidation.h"
#include "Validation/EventGenerator/interface/HepMCValidationHelper.h"
#include "TLorentzVector.h"

#include "CLHEP/Units/defs.h"
#include "CLHEP/Units/PhysicalConstants.h"

#include "DataFormats/Math/interface/LorentzVector.h"

using namespace edm;

WValidation::WValidation(const edm::ParameterSet& iPSet):  
  hepmcCollection_(iPSet.getParameter<edm::InputTag>("hepmcCollection")),
  _flavor(iPSet.getParameter<int>("decaysTo")),
  _name(iPSet.getParameter<std::string>("name")) 
{    
  dbe = 0;
  dbe = edm::Service<DQMStore>().operator->();
}

WValidation::~WValidation() {}

void WValidation::beginJob()
{
  if(dbe){
    std::string folderName = "Generator/W";
    folderName+=_name;
    dbe->setCurrentFolder(folderName.c_str());
    
    // Number of analyzed events
    nEvt = dbe->book1D("nEvt", "n analyzed Events", 1, 0., 1.);
    
    //Kinematics
    Wmass = dbe->book1D("Wmass","inv. Mass W", 70 ,0,140);
    WmassPeak = dbe->book1D("WmassPeak","inv. Mass W", 80 ,80 ,100);
    Wpt = dbe->book1D("Wpt","W pt",100,0,200);
    WptLog = dbe->book1D("WptLog","log(W pt)",100,0.,5.);
    Wrap = dbe->book1D("Wrap", "W y", 100, -5, 5);
    Wdaughters = dbe->book1D("Wdaughters", "W daughters", 60, -30, 30);

    lepmet_mT = dbe->book1D("lepmet_mT","lepton-met transverse mass", 70 ,0,140);
    lepmet_mTPeak = dbe->book1D("lepmet_mTPeak","lepton-met transverse mass", 80 ,80 ,100);
    lepmet_pt = dbe->book1D("lepmet_pt","lepton-met",100,0,200);
    lepmet_ptLog = dbe->book1D("lepmet_ptLog","log(lepton-met pt)",100,0.,5.);

    gamma_energy = dbe->book1D("gamma_energy", "photon energy in W rest frame", 200, 0., 100.);
    cos_theta_gamma_lepton = dbe->book1D("cos_theta_gamma_lepton",      "cos_theta_gamma_lepton in W rest frame",      200, -1, 1);

    leppt = dbe->book1D("leadpt","lepton pt", 200, 0., 200.);    
    met   = dbe->book1D("met","met", 200, 0., 200.);    
    lepeta = dbe->book1D("leadeta","leading lepton eta", 100, -5., 5.);

  }
  return;
}

void WValidation::endJob(){return;}
void WValidation::beginRun(const edm::Run& iRun,const edm::EventSetup& iSetup)
{
  iSetup.getData( fPDGTable );
  return;
}
void WValidation::endRun(const edm::Run& iRun,const edm::EventSetup& iSetup){return;}
void WValidation::analyze(const edm::Event& iEvent,const edm::EventSetup& iSetup)
{ 
  
  // we *DO NOT* rely on a Z entry in the particle listings!

  edm::Handle<HepMCProduct> evt;
  iEvent.getByLabel(hepmcCollection_, evt);

  //Get EVENT
  const HepMC::GenEvent *myGenEvent = evt->GetEvent();

  nEvt->Fill(0.5);

  std::vector<const HepMC::GenParticle*> allleptons; 
  std::vector<const HepMC::GenParticle*> allneutrinos; 

  //requires status 1 for leptons and neutrinos (except tau)
  int requiredstatus = (abs(_flavor) == 11 || abs(_flavor) ==13 ) ? 1 : 3;

  bool vetotau = true; //(abs(_flavor) == 11 || abs(_flavor) == 12 || abs(_flavor) ==13 || abs(_flavor) ==14 || abs(_flavor) ==16) ? true : false;  

  for(HepMC::GenEvent::particle_const_iterator iter = myGenEvent->particles_begin(); iter != myGenEvent->particles_end(); ++iter) {
    if (vetotau) {
      if ((*iter)->status()==3 && abs((*iter)->pdg_id() == 15) ) return;
    }
    if((*iter)->status()==requiredstatus) {
      //@todo: improve this selection   
      if((*iter)->pdg_id()==_flavor)
        allleptons.push_back(*iter);
      else if (abs((*iter)->pdg_id()) == abs(_flavor)+1)
        allneutrinos.push_back(*iter);  
    }
  }
 
  //nothing to do if we don't have 2 particles
  if (allleptons.empty() || allneutrinos.empty()) return;

  //sort them in pt
  std::sort(allleptons.begin(), allleptons.end(), HepMCValidationHelper::sortByPt); 
  std::sort(allneutrinos.begin(), allneutrinos.end(), HepMCValidationHelper::sortByPt); 

  //get the first lepton and the first neutrino, and check that one is particle one is antiparticle (product of pdgids < 0) 
  std::vector<const HepMC::GenParticle*> products;
  if (allleptons.front()->pdg_id() * allneutrinos.front()->pdg_id() > 0) return;        

  //require at least 20 GeV on the lepton
  if (allleptons.front()->momentum().perp() < 20. || allneutrinos.front()->momentum().perp() < 20. ) return;

  //find possible qed fsr photons
  std::vector<const HepMC::GenParticle*> selectedLepton;
  selectedLepton.push_back(allleptons.front()); 
  std::vector<const HepMC::GenParticle*> fsrphotons;
  HepMCValidationHelper::findFSRPhotons(selectedLepton, myGenEvent, 0.1, fsrphotons);

  Wdaughters->Fill(allleptons.front()->pdg_id()); 
  Wdaughters->Fill(allneutrinos.front()->pdg_id()); 
 
  //assemble FourMomenta
  TLorentzVector lep1(allleptons[0]->momentum().x(), allleptons[0]->momentum().y(), allleptons[0]->momentum().z(), allleptons[0]->momentum().t()); 
  TLorentzVector lep2(allneutrinos[0]->momentum().x(), allneutrinos[0]->momentum().y(), allneutrinos[0]->momentum().z(), allneutrinos[0]->momentum().t()); 
  TLorentzVector dilepton_mom = lep1 + lep2;
  TLorentzVector dilepton_andphoton_mom = dilepton_mom;
  std::vector<TLorentzVector> gammasMomenta;
  for (unsigned int ipho = 0; ipho < fsrphotons.size(); ++ipho){
    TLorentzVector phomom(fsrphotons[ipho]->momentum().x(), fsrphotons[ipho]->momentum().y(), fsrphotons[ipho]->momentum().z(), fsrphotons[ipho]->momentum().t()); 
    dilepton_andphoton_mom += phomom;
    Wdaughters->Fill(fsrphotons[ipho]->pdg_id());
    gammasMomenta.push_back(phomom);
  }  
  //Fill "true" W histograms
  Wmass->Fill(dilepton_andphoton_mom.M());
  WmassPeak->Fill(dilepton_andphoton_mom.M());
  Wpt->Fill(dilepton_andphoton_mom.Pt());
  WptLog->Fill(log10(dilepton_andphoton_mom.Pt())); 
  Wrap->Fill(dilepton_andphoton_mom.Rapidity());

  TLorentzVector met_mom = HepMCValidationHelper::genMet(myGenEvent, -3., 3.);
  TLorentzVector lep1T(lep1.Px(), lep1.Py(), 0., lep1.Et());
  TLorentzVector lepmet_mom = lep1T + met_mom;
  //Fill lepmet histograms
  lepmet_mT->Fill(lepmet_mom.M());
  lepmet_mTPeak->Fill(lepmet_mom.M());
  lepmet_pt->Fill(lepmet_mom.Pt());
  lepmet_ptLog->Fill(log10(lepmet_mom.Pt()));

  //Fill lepton histograms 
  leppt->Fill(lep1.Pt());
  lepeta->Fill(lep1.Eta());
  met->Fill(met_mom.Pt());      

  //boost everything in the W frame
  TVector3 boost = dilepton_andphoton_mom.BoostVector();
  boost*=-1.;
  lep1.Boost(boost);
  lep2.Boost(boost);
  for (unsigned int ipho = 0; ipho < gammasMomenta.size(); ++ipho){
    gammasMomenta[ipho].Boost(boost);
  }
  std::sort(gammasMomenta.begin(), gammasMomenta.end(), HepMCValidationHelper::GreaterByE<TLorentzVector>);

  //fill gamma histograms
  if (gammasMomenta.size() != 0 && dilepton_andphoton_mom.M() > 50.) {
    gamma_energy->Fill(gammasMomenta.front().E());
    double dphi = lep1.DeltaR(gammasMomenta.front());
    cos_theta_gamma_lepton->Fill(cos(dphi));
  } 


}//analyze