Inheritance diagram for PFRecoTauDiscriminationByFlight:

Public Member Functions
void	beginEvent (const edm::Event &evt, const edm::EventSetup &es)
double	discriminate (const reco::PFTauRef &)
	PFRecoTauDiscriminationByFlight (const edm::ParameterSet &pset)
virtual	~PFRecoTauDiscriminationByFlight ()
Private Attributes
edm::Handle< reco::BeamSpot >	beamspot_
edm::InputTag	bsSource_
const TransientTrackBuilder *	builder_
double	oneProngSig_
bool	refitPV_
double	threeProngSig_
edm::InputTag	vertexSource_
edm::Handle < reco::VertexCollection >	vertices_

Detailed Description

Definition at line 14 of file RecoTauDiscriminationByFlight.cc.

Constructor & Destructor Documentation

PFRecoTauDiscriminationByFlight::PFRecoTauDiscriminationByFlight ( const edm::ParameterSet & pset )

Definition at line 31 of file RecoTauDiscriminationByFlight.cc.

References bsSource_, edm::ParameterSet::exists(), edm::ParameterSet::getParameter(), oneProngSig_, refitPV_, threeProngSig_, and vertexSource_.

                                :PFTauDiscriminationProducerBase(pset) {
  vertexSource_ = pset.getParameter<edm::InputTag>("vertexSource");
  oneProngSig_ = pset.exists("oneProngSigCut") ?
    pset.getParameter<double>("oneProngSigCut") : -1.;
  threeProngSig_ = pset.exists("threeProngSigCut") ?
    pset.getParameter<double>("threeProngSigCut") : -1.;
  refitPV_ = pset.getParameter<bool>("refitPV");
  if (refitPV_)
    bsSource_ = pset.getParameter<edm::InputTag>("beamspot");
}

virtual PFRecoTauDiscriminationByFlight::~PFRecoTauDiscriminationByFlight ( ) [inline, virtual]

Definition at line 17 of file RecoTauDiscriminationByFlight.cc.

{}

Member Function Documentation

void PFRecoTauDiscriminationByFlight::beginEvent	(	const edm::Event &	evt,
		const edm::EventSetup &	es
	)		`[virtual]`

Reimplemented from TauDiscriminationProducerBase< TauType, TauDiscriminator >.

Definition at line 43 of file RecoTauDiscriminationByFlight.cc.

References beamspot_, bsSource_, builder_, edm::EventSetup::get(), edm::Event::getByLabel(), edm::ESHandle< T >::product(), refitPV_, vertexSource_, and vertices_.

                                                  {
  evt.getByLabel(vertexSource_, vertices_);
  if (refitPV_)
    evt.getByLabel(bsSource_, beamspot_);
  edm::ESHandle<TransientTrackBuilder> transTrackBuilder;
  es.get<TransientTrackRecord>().get("TransientTrackBuilder",transTrackBuilder);
  builder_ = transTrackBuilder.product();
}

double PFRecoTauDiscriminationByFlight::discriminate ( const reco::PFTauRef & tau )

Definition at line 53 of file RecoTauDiscriminationByFlight.cc.

References beamspot_, TransientTrackBuilder::build(), builder_, reco::SecondaryVertex::computeDist2d(), edm::Ref< C, T, F >::isNonnull(), TauDiscriminationProducerBase< TauType, TauDiscriminator >::prediscriminantFailValue_, refitPV_, IPTools::signedTransverseImpactParameter(), Measurement1D::significance(), python::multivaluedict::sort(), reco::Vertex::tracks_begin(), reco::Vertex::tracks_end(), and KalmanVertexFitter::vertex().

                             {

  KalmanVertexFitter kvf(true);
  const reco::PFCandidateRefVector& signalTracks =
    tau->signalPFChargedHadrCands();
  std::vector<reco::TransientTrack> signalTransTracks;
  std::vector<reco::TrackRef> signalTrackRefs;
  BOOST_FOREACH(const reco::PFCandidateRef& pftrack, signalTracks) {
    if (pftrack->trackRef().isNonnull()) {
      signalTransTracks.push_back(
          builder_->build(pftrack->trackRef()));
      signalTrackRefs.push_back(pftrack->trackRef());
    }
  }

  reco::Vertex pv = (*vertices_)[0];

  if (refitPV_) {
    std::vector<reco::TrackRef> pvTrackRefs;
    for (reco::Vertex::trackRef_iterator pvTrack = pv.tracks_begin();
        pvTrack != pv.tracks_end(); ++pvTrack ) {
      pvTrackRefs.push_back(pvTrack->castTo<reco::TrackRef>());
    }
    // Get PV tracks not associated to the tau
    std::sort(signalTrackRefs.begin(), signalTrackRefs.end());
    std::sort(pvTrackRefs.begin(), pvTrackRefs.end());
    std::vector<reco::TrackRef> uniquePVTracks;
    uniquePVTracks.reserve(pvTrackRefs.size());
    std::set_difference(pvTrackRefs.begin(), pvTrackRefs.end(),
        signalTrackRefs.begin(), signalTrackRefs.end(),
        std::back_inserter(uniquePVTracks));
    // Check if we need to refit
    if (uniquePVTracks.size() != pvTrackRefs.size()) {
      std::vector<reco::TransientTrack> pvTransTracks;
      // Build all our unique transient tracks in the PV
      BOOST_FOREACH(const reco::TrackRef& track, pvTrackRefs) {
        pvTransTracks.push_back(builder_->build(track));
      }
      // Refit our PV
      TransientVertex newPV = kvf.vertex(pvTransTracks, *beamspot_);
      pv = newPV;
    }
  }

  // The tau direction, to determine the sign of the IP.
  // In the case that it is a one prong, take the jet direction.
  // This may give better result due to out-of-cone stuff.
  GlobalVector direction = (tau->signalPFCands().size() == 1 ?
      GlobalVector(
          tau->jetRef()->px(), tau->jetRef()->py(), tau->jetRef()->pz()) :
      GlobalVector(tau->px(), tau->py(), tau->pz()));

  // Now figure out of we are doing a SV fit or an IP significance
  if (signalTransTracks.size() == 1) {
    reco::TransientTrack track = signalTransTracks.front();
    std::pair<bool,Measurement1D> ipsig =
      IPTools::signedTransverseImpactParameter(track, direction, pv);
    if (ipsig.first)
      return ipsig.second.significance();
    else
      return prediscriminantFailValue_;
  } else if (signalTransTracks.size() == 3) {
    // Fit the decay vertex of the three prong
    TransientVertex sv = kvf.vertex(signalTransTracks);
    // the true parameter indicates include PV errors
    Measurement1D svDist = reco::SecondaryVertex::computeDist2d(
        pv, sv, direction, true);
    double significance = svDist.significance();
    // Make sure it is a sane value
    if (significance > 40)
      significance = 40;
    if (significance < -20)
      significance = -20;
    return significance;
  } else  {
    // Weird two prong or something
    return prediscriminantFailValue_;
  }
}