PFTauTransverseImpactParameters.cc

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/* class PFTauTransverseImpactParamters
 * EDProducer of the 
 * authors: Ian M. Nugent
 * This work is based on the impact parameter work by Rosamaria Venditti and reconstructing the 3 prong taus.
 * The idea of the fully reconstructing the tau using a kinematic fit comes from
 * Lars Perchalla and Philip Sauerland Theses under Achim Stahl supervision. This
 * work was continued by Ian M. Nugent and Vladimir Cherepanov.
 * Thanks goes to Christian Veelken and Evan Klose Friis for their help and suggestions.
 */


#include "FWCore/Framework/interface/EventSetup.h"
#include "FWCore/Framework/interface/ESHandle.h"
#include "FWCore/Framework/interface/Event.h"
#include "FWCore/Framework/interface/MakerMacros.h"
#include "FWCore/Framework/interface/Frameworkfwd.h"
#include "FWCore/Framework/interface/stream/EDProducer.h"
#include "FWCore/ParameterSet/interface/ParameterSet.h"
#include "FWCore/MessageLogger/interface/MessageLogger.h"
#include "FWCore/Utilities/interface/Exception.h"

#include "TrackingTools/TransientTrack/interface/TransientTrackBuilder.h"
#include "TrackingTools/Records/interface/TransientTrackRecord.h"
#include "RecoVertex/VertexPrimitives/interface/TransientVertex.h"
#include "RecoBTag/SecondaryVertex/interface/SecondaryVertex.h"
#include "TrackingTools/IPTools/interface/IPTools.h"
#include "RecoVertex/VertexPrimitives/interface/ConvertToFromReco.h"
#include "TrackingTools/GeomPropagators/interface/AnalyticalTrajectoryExtrapolatorToLine.h"
#include "TrackingTools/GeomPropagators/interface/AnalyticalImpactPointExtrapolator.h"

#include "DataFormats/TauReco/interface/PFTau.h"
#include "DataFormats/TauReco/interface/PFTauFwd.h"
#include "DataFormats/VertexReco/interface/Vertex.h"
#include "DataFormats/VertexReco/interface/VertexFwd.h"
#include "DataFormats/TrackReco/interface/Track.h"
#include "DataFormats/TrackReco/interface/TrackFwd.h"
#include "DataFormats/TauReco/interface/PFTauTransverseImpactParameter.h"
#include "DataFormats/TauReco/interface/PFTauTransverseImpactParameterFwd.h"

#include "DataFormats/Common/interface/Association.h"
#include "DataFormats/Common/interface/AssociationVector.h"
#include "DataFormats/Common/interface/RefProd.h"
#include "TMath.h"

#include <memory>

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

class PFTauTransverseImpactParameters : public edm::stream::EDProducer<> {
 public:
  enum CMSSWPerigee{aCurv=0,aTheta,aPhi,aTip,aLip};
  explicit PFTauTransverseImpactParameters(const edm::ParameterSet& iConfig);
  ~PFTauTransverseImpactParameters() override;
  void produce(edm::Event&,const edm::EventSetup&) override;
 private:
  edm::EDGetTokenT<std::vector<reco::PFTau> > PFTauToken_;
  edm::EDGetTokenT<edm::AssociationVector<PFTauRefProd, std::vector<reco::VertexRef> > > PFTauPVAToken_;
  edm::EDGetTokenT<edm::AssociationVector<PFTauRefProd,std::vector<std::vector<reco::VertexRef> > > > PFTauSVAToken_;
  bool useFullCalculation_;
};

PFTauTransverseImpactParameters::PFTauTransverseImpactParameters(const edm::ParameterSet& iConfig):
  PFTauToken_(consumes<std::vector<reco::PFTau> >(iConfig.getParameter<edm::InputTag>("PFTauTag"))),
  PFTauPVAToken_(consumes<edm::AssociationVector<PFTauRefProd, std::vector<reco::VertexRef> > >(iConfig.getParameter<edm::InputTag>("PFTauPVATag"))),
  PFTauSVAToken_(consumes<edm::AssociationVector<PFTauRefProd,std::vector<std::vector<reco::VertexRef> > > >(iConfig.getParameter<edm::InputTag>("PFTauSVATag"))),
  useFullCalculation_(iConfig.getParameter<bool>("useFullCalculation"))
{
  produces<edm::AssociationVector<PFTauRefProd, std::vector<reco::PFTauTransverseImpactParameterRef> > >(); 
  produces<PFTauTransverseImpactParameterCollection>("PFTauTIP");
}

PFTauTransverseImpactParameters::~PFTauTransverseImpactParameters(){

}

void PFTauTransverseImpactParameters::produce(edm::Event& iEvent,const edm::EventSetup& iSetup){
  // Obtain Collections
  edm::ESHandle<TransientTrackBuilder> transTrackBuilder;
  iSetup.get<TransientTrackRecord>().get("TransientTrackBuilder",transTrackBuilder);
  
  edm::Handle<std::vector<reco::PFTau> > Tau;
  iEvent.getByToken(PFTauToken_,Tau);

  edm::Handle<edm::AssociationVector<PFTauRefProd, std::vector<reco::VertexRef> > > PFTauPVA;
  iEvent.getByToken(PFTauPVAToken_,PFTauPVA);

  edm::Handle<edm::AssociationVector<PFTauRefProd,std::vector<std::vector<reco::VertexRef> > > > PFTauSVA;
  iEvent.getByToken(PFTauSVAToken_,PFTauSVA);

  // Set Association Map
  auto AVPFTauTIP = std::make_unique< edm::AssociationVector<PFTauRefProd, std::vector<reco::PFTauTransverseImpactParameterRef>>>(PFTauRefProd(Tau));
  auto TIPCollection_out = std::make_unique<PFTauTransverseImpactParameterCollection>();
  reco::PFTauTransverseImpactParameterRefProd TIPRefProd_out = iEvent.getRefBeforePut<reco::PFTauTransverseImpactParameterCollection>("PFTauTIP");

  // For each Tau Run Algorithim
  if(Tau.isValid()) {
    for(reco::PFTauCollection::size_type iPFTau = 0; iPFTau < Tau->size(); iPFTau++) {
      reco::PFTauRef RefPFTau(Tau, iPFTau);
      const reco::VertexRef PV=PFTauPVA->value(RefPFTau.key());
      const std::vector<reco::VertexRef> SV=PFTauSVA->value(RefPFTau.key());
      double dxy(-999), dxy_err(-999);
      reco::Vertex::Point poca(0,0,0);
      double ip3d(-999), ip3d_err(-999);
      reco::Vertex::Point ip3d_poca(0,0,0);
      if(RefPFTau->leadPFChargedHadrCand().isNonnull()){
    const reco::Track* track = nullptr;
    if(RefPFTau->leadPFChargedHadrCand()->trackRef().isNonnull())
      track = RefPFTau->leadPFChargedHadrCand()->trackRef().get();
    else if(RefPFTau->leadPFChargedHadrCand()->gsfTrackRef().isNonnull())
      track = RefPFTau->leadPFChargedHadrCand()->gsfTrackRef().get();
    if(track != nullptr){
      if(useFullCalculation_){
        reco::TransientTrack transTrk=transTrackBuilder->build(*track);
        GlobalVector direction(RefPFTau->p4().px(), RefPFTau->p4().py(), RefPFTau->p4().pz()); //To compute sign of IP
        std::pair<bool,Measurement1D> signed_IP2D = IPTools::signedTransverseImpactParameter(transTrk, direction, (*PV));
        dxy=signed_IP2D.second.value();
        dxy_err=signed_IP2D.second.error();
        std::pair<bool,Measurement1D> signed_IP3D = IPTools::signedImpactParameter3D(transTrk, direction, (*PV));
        ip3d=signed_IP3D.second.value();
        ip3d_err=signed_IP3D.second.error();
        TransverseImpactPointExtrapolator extrapolator(transTrk.field());
        GlobalPoint pos  = extrapolator.extrapolate(transTrk.impactPointState(), RecoVertex::convertPos(PV->position())).globalPosition();
        poca=reco::Vertex::Point(pos.x(),pos.y(),pos.z());
        AnalyticalImpactPointExtrapolator extrapolator3D(transTrk.field());
        GlobalPoint pos3d = extrapolator3D.extrapolate(transTrk.impactPointState(),RecoVertex::convertPos(PV->position())).globalPosition();
        ip3d_poca=reco::Vertex::Point(pos3d.x(),pos3d.y(),pos3d.z());
      }
      else{
        dxy_err=track->d0Error();
        dxy=track->dxy(PV->position());
        ip3d_err=track->dzError(); //store dz, ip3d not available
        ip3d=track->dz(PV->position()); //store dz, ip3d not available
      }
    }
      }
      if(!SV.empty()){
    reco::Vertex::CovarianceMatrix cov;
    reco::Vertex::Point v(SV.at(0)->x()-PV->x(),SV.at(0)->y()-PV->y(),SV.at(0)->z()-PV->z());
    for(int i=0;i<reco::Vertex::dimension;i++){
      for(int j=0;j<reco::Vertex::dimension;j++){
        cov(i,j)=SV.at(0)->covariance(i,j)+PV->covariance(i,j);
      }
    }
    GlobalVector direction(RefPFTau->px(),RefPFTau->py(),RefPFTau->pz());
    double vSig = SecondaryVertex::computeDist3d(*PV,*SV.at(0),direction,true).significance();
    reco::PFTauTransverseImpactParameter TIPV(poca,dxy,dxy_err,ip3d_poca,ip3d,ip3d_err,PV,v,vSig,SV.at(0));
    reco::PFTauTransverseImpactParameterRef TIPVRef=reco::PFTauTransverseImpactParameterRef(TIPRefProd_out,TIPCollection_out->size());
        TIPCollection_out->push_back(TIPV);
        AVPFTauTIP->setValue(iPFTau,TIPVRef);
      }
      else{ 
    reco::PFTauTransverseImpactParameter TIPV(poca,dxy,dxy_err,ip3d_poca,ip3d,ip3d_err,PV);
    reco::PFTauTransverseImpactParameterRef TIPVRef=reco::PFTauTransverseImpactParameterRef(TIPRefProd_out,TIPCollection_out->size());
    TIPCollection_out->push_back(TIPV);
    AVPFTauTIP->setValue(iPFTau,TIPVRef);
      }
    }
  }
  iEvent.put(std::move(TIPCollection_out),"PFTauTIP");
  iEvent.put(std::move(AVPFTauTIP));
}

DEFINE_FWK_MODULE(PFTauTransverseImpactParameters);