PatBJetVertexAnalyzer Class Reference

Inheritance diagram for PatBJetVertexAnalyzer:

Classes
struct	Plots

Public Member Functions
virtual void	analyze (const edm::Event &event, const edm::EventSetup &es)
virtual void	beginJob ()
	PatBJetVertexAnalyzer (const edm::ParameterSet &params)
	constructor and destructor More...
	~PatBJetVertexAnalyzer ()
Public Member Functions inherited from edm::EDAnalyzer
	EDAnalyzer ()
std::string	workerType () const
virtual	~EDAnalyzer ()

Private Types
enum	Flavour {   ALL_JETS = 0, UDSG_JETS, C_JETS, B_JETS,   NONID_JETS, N_JET_TYPES }

Private Attributes
TH1 *	flavours_
double	jetEtaCut_
double	jetPtCut_
edm::InputTag	jets_
double	maxDeltaR_
struct PatBJetVertexAnalyzer::Plots	plots_ [N_JET_TYPES]

Additional Inherited Members
Public Types inherited from edm::EDAnalyzer
typedef EDAnalyzer	ModuleType
typedef WorkerT< EDAnalyzer >	WorkerType
Static Public Member Functions inherited from edm::EDAnalyzer
static const std::string &	baseType ()
static void	fillDescriptions (ConfigurationDescriptions &descriptions)
Protected Member Functions inherited from edm::EDAnalyzer
CurrentProcessingContext const *	currentContext () const

Detailed Description

Definition at line 33 of file PatBJetVertexAnalyzer.cc.

Member Enumeration Documentation

enum PatBJetVertexAnalyzer::Flavour

private

Enumerator
ALL_JETS
UDSG_JETS
C_JETS
B_JETS
NONID_JETS
N_JET_TYPES

Definition at line 53 of file PatBJetVertexAnalyzer.cc.

                 {
        ALL_JETS = 0,
        UDSG_JETS,
        C_JETS,
        B_JETS,
        NONID_JETS,
        N_JET_TYPES
    };

Constructor & Destructor Documentation

PatBJetVertexAnalyzer::PatBJetVertexAnalyzer

(

const edm::ParameterSet &

params

)

constructor and destructor

Definition at line 72 of file PatBJetVertexAnalyzer.cc.

                                                                          :
    jets_(params.getParameter<edm::InputTag>("jets")),
    jetPtCut_(params.getParameter<double>("jetPtCut")),
    jetEtaCut_(params.getParameter<double>("jetEtaCut"))
{
}

PatBJetVertexAnalyzer::~PatBJetVertexAnalyzer

(

)

Definition at line 79 of file PatBJetVertexAnalyzer.cc.

{
}

Member Function Documentation

void PatBJetVertexAnalyzer::analyze ( const edm::Event &  event, const edm::EventSetup &  es  )

virtual

Implements edm::EDAnalyzer.

Definition at line 148 of file PatBJetVertexAnalyzer.cc.

References abs, ALL_JETS, B_JETS, C_JETS, PatBJetVertexAnalyzer::Plots::chi2, reco::Vertex::chi2(), deltaR(), PatBJetVertexAnalyzer::Plots::deltaR, dir, PatBJetVertexAnalyzer::Plots::dist, PatBJetVertexAnalyzer::Plots::distErr, PatBJetVertexAnalyzer::Plots::distSig, Measurement1D::error(), reco::flavour(), flavours_, reco::SecondaryVertexTagInfo::flightDirection(), reco::SecondaryVertexTagInfo::flightDistance(), metsig::jet, jetEtaCut_, jetPtCut_, jets_, PatBJetVertexAnalyzer::Plots::mass, NONID_JETS, PatBJetVertexAnalyzer::Plots::nTracks, PatBJetVertexAnalyzer::Plots::nVertices, reco::SecondaryVertexTagInfo::nVertices(), plots_, reco::SecondaryVertexTagInfo::secondaryVertex(), Measurement1D::significance(), reco::Vertex::tracks_begin(), reco::Vertex::tracks_end(), reco::Vertex::tracksSize(), UDSG_JETS, Measurement1D::value(), reco::btau::vertexMass, PV3DBase< T, PVType, FrameType >::x(), PV3DBase< T, PVType, FrameType >::y(), and PV3DBase< T, PVType, FrameType >::z().

{  
    // handle to the jets collection
    edm::Handle<pat::JetCollection> jetsHandle;
    event.getByLabel(jets_, jetsHandle);

    // now go through all jets
    for(pat::JetCollection::const_iterator jet = jetsHandle->begin();
        jet != jetsHandle->end(); ++jet) {

        // only look at jets that pass the pt and eta cut
        if (jet->pt() < jetPtCut_ ||
            std::abs(jet->eta()) > jetEtaCut_)
            continue;

        Flavour flavour;
        // find out the jet flavour (differs between quark and anti-quark)
        switch(std::abs(jet->partonFlavour())) {
            case 1:
            case 2:
            case 3:
            case 21:
            flavour = UDSG_JETS;
            break;
            case 4:
            flavour = C_JETS;
            break;
            case 5:
            flavour = B_JETS;
            break;
            default:
            flavour = NONID_JETS;
        }

        // simply count the number of accepted jets
        flavours_->Fill(ALL_JETS);
        flavours_->Fill(flavour);

        // retrieve the "secondary vertex tag infos"
        // this is the output of the b-tagging reconstruction code
        // and contains secondary vertices in the jets
        const reco::SecondaryVertexTagInfo &svTagInfo =
                    *jet->tagInfoSecondaryVertex();

        // count the number of secondary vertices
        plots_[ALL_JETS].nVertices->Fill(svTagInfo.nVertices());
        plots_[flavour].nVertices->Fill(svTagInfo.nVertices());

        // ignore jets without SV from now on
        if (svTagInfo.nVertices() < 1)
            continue;

        // pick the first secondary vertex (the "best" one)
        const reco::Vertex &sv = svTagInfo.secondaryVertex(0);

        // and plot number of tracks and chi^2
        plots_[ALL_JETS].nTracks->Fill(sv.tracksSize());
        plots_[flavour].nTracks->Fill(sv.tracksSize());

        plots_[ALL_JETS].chi2->Fill(sv.chi2());
        plots_[flavour].chi2->Fill(sv.chi2());

        // the precomputed transverse distance to the primary vertex
        Measurement1D distance = svTagInfo.flightDistance(0, true);

        plots_[ALL_JETS].dist->Fill(distance.value());
        plots_[flavour].dist->Fill(distance.value());

        plots_[ALL_JETS].distErr->Fill(distance.error());
        plots_[flavour].distErr->Fill(distance.error());

        plots_[ALL_JETS].distSig->Fill(distance.significance());
        plots_[flavour].distSig->Fill(distance.significance());


        // the precomputed direction with respect to the primary vertex
        GlobalVector dir = svTagInfo.flightDirection(0);

        // unfortunately CMSSW hsa all kinds of vectors,
        // and sometimes we need to convert them *sigh*
        math::XYZVector dir2(dir.x(), dir.y(), dir.z());

        // compute a few variables that we are plotting
        double deltaR = ROOT::Math::VectorUtil::DeltaR(
                        jet->momentum(), dir2);

        plots_[ALL_JETS].deltaR->Fill(deltaR);
        plots_[flavour].deltaR->Fill(deltaR);

        // compute the invariant mass from a four-vector sum
        math::XYZTLorentzVector trackFourVectorSum;

        // loop over all tracks in the vertex
        for(reco::Vertex::trackRef_iterator track = sv.tracks_begin();
            track != sv.tracks_end(); ++track) {
            ROOT::Math::LorentzVector<ROOT::Math::PxPyPzM4D<double> > vec;
            vec.SetPx((*track)->px());
            vec.SetPy((*track)->py());
            vec.SetPz((*track)->pz());
            vec.SetM(0.13957);  // pion mass
            trackFourVectorSum += vec;
        }

        // get the invariant mass: sqrt(E² - px² - py² - pz²)
        double vertexMass = trackFourVectorSum.M();

        plots_[ALL_JETS].mass->Fill(vertexMass);
        plots_[flavour].mass->Fill(vertexMass);
    }
}

void PatBJetVertexAnalyzer::beginJob ( void  )

virtual

Reimplemented from edm::EDAnalyzer.

Definition at line 83 of file PatBJetVertexAnalyzer.cc.

References ALL_JETS, B_JETS, C_JETS, PatBJetVertexAnalyzer::Plots::chi2, PatBJetVertexAnalyzer::Plots::deltaR, PatBJetVertexAnalyzer::Plots::dist, PatBJetVertexAnalyzer::Plots::distErr, PatBJetVertexAnalyzer::Plots::distSig, reco::flavour(), flavours_, i, TFileDirectory::make(), PatBJetVertexAnalyzer::Plots::mass, N_JET_TYPES, mergeVDriftHistosByStation::name, PatBJetVertexAnalyzer::Plots::nTracks, PatBJetVertexAnalyzer::Plots::nVertices, plots_, and UDSG_JETS.

{
    // retrieve handle to auxiliary service
    //  used for storing histograms into ROOT file
    edm::Service<TFileService> fs;

    flavours_ = fs->make<TH1F>("flavours", "jet flavours", 5, 0, 5);

    // book histograms for all jet flavours
    for(unsigned int i = 0; i < N_JET_TYPES; i++) {
        Plots &plots = plots_[i];
        const char *flavour, *name;

        switch((Flavour)i) {
            case ALL_JETS:
            flavour = "all jets";
            name = "all";
            break;
            case UDSG_JETS:
            flavour = "light flavour jets";
            name = "udsg";
            break;
            case C_JETS:
            flavour = "charm jets";
            name = "c";
            break;
            case B_JETS:
            flavour = "bottom jets";
            name = "b";
            break;
            default:
            flavour = "unidentified jets";
            name = "ni";
            break;
        }

        plots.nVertices = fs->make<TH1F>(Form("nVertices_%s", name),
                                         Form("number of secondary vertices in %s", flavour),
                                         5, 0, 5);
        plots.deltaR = fs->make<TH1F>(Form("deltaR_%s", name),
                                      Form("\\DeltaR between vertex direction and jet direction in %s", flavour),
                                      100, 0, 0.5);
        plots.mass = fs->make<TH1F>(Form("mass_%s", name),
                                    Form("vertex mass in %s", flavour),
                                    100, 0, 10);
        plots.dist = fs->make<TH1F>(Form("dist_%s", name),
                                    Form("Transverse distance between PV and SV in %s", flavour),
                                    100, 0, 2);
        plots.distErr = fs->make<TH1F>(Form("distErr_%s", name),
                                       Form("Transverse distance error between PV and SV in %s", flavour),
                                       100, 0, 0.5);
        plots.distSig = fs->make<TH1F>(Form("distSig_%s", name),
                                       Form("Transverse distance significance between PV and SV in %s", flavour),
                                       100, 0, 50);
        plots.nTracks = fs->make<TH1F>(Form("nTracks_%s", name),
                                       Form("number of tracks at secondary vertex in %s", flavour),
                                       20, 0, 20);
        plots.chi2 = fs->make<TH1F>(Form("chi2_%s", name),
                                    Form("secondary vertex fit \\chi^{2} in %s", flavour),
                                    100, 0, 50);
    }
}

Member Data Documentation

TH1* PatBJetVertexAnalyzer::flavours_

private

Definition at line 62 of file PatBJetVertexAnalyzer.cc.

Referenced by analyze(), and beginJob().

double PatBJetVertexAnalyzer::jetEtaCut_

private

Definition at line 48 of file PatBJetVertexAnalyzer.cc.

Referenced by analyze().

double PatBJetVertexAnalyzer::jetPtCut_

private

Definition at line 47 of file PatBJetVertexAnalyzer.cc.

Referenced by analyze().

edm::InputTag PatBJetVertexAnalyzer::jets_

private

Definition at line 45 of file PatBJetVertexAnalyzer.cc.

Referenced by analyze().

double PatBJetVertexAnalyzer::maxDeltaR_

private

Definition at line 49 of file PatBJetVertexAnalyzer.cc.

struct PatBJetVertexAnalyzer::Plots PatBJetVertexAnalyzer::plots_[N_JET_TYPES]

private

Referenced by analyze(), and beginJob().