/data/doxygen/doxygen-1.7.3/gen/CMSSW_4_2_8/src/RecoBTag/SecondaryVertex/src/V0Filter.cc

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#include <cmath>

#include <Math/GenVector/PxPyPzM4D.h>

#include "FWCore/ParameterSet/interface/ParameterSet.h"

#include "DataFormats/Math/interface/LorentzVector.h"
#include "DataFormats/TrackReco/interface/Track.h"
#include "DataFormats/TrackReco/interface/TrackFwd.h"

#include "RecoBTag/SecondaryVertex/interface/ParticleMasses.h"
#include "RecoBTag/SecondaryVertex/interface/V0Filter.h"

using namespace reco; 

V0Filter::V0Filter(const edm::ParameterSet &params) :
        k0sMassWindow(params.getParameter<double>("k0sMassWindow"))
{
}

inline bool
V0Filter::operator () (const reco::Track **tracks, unsigned int n) const
{
        // only check for K0s for now

        if (n != 2)
                return true;

        if (tracks[0]->charge() * tracks[1]->charge() > 0)
                return true;

        ROOT::Math::LorentzVector<ROOT::Math::PxPyPzM4D<double> > vec1;
        ROOT::Math::LorentzVector<ROOT::Math::PxPyPzM4D<double> > vec2;

        vec1.SetPx(tracks[0]->px());
        vec1.SetPy(tracks[0]->py());
        vec1.SetPz(tracks[0]->pz());
        vec1.SetM(ParticleMasses::piPlus);

        vec2.SetPx(tracks[1]->px());
        vec2.SetPy(tracks[1]->py());
        vec2.SetPz(tracks[1]->pz());
        vec2.SetM(ParticleMasses::piPlus);

        double invariantMass = (vec1 + vec2).M();
        if (std::abs(invariantMass - ParticleMasses::k0) < k0sMassWindow)
                return false;

        return true;
}

bool
V0Filter::operator () (const reco::TrackRef *tracks, unsigned int n) const
{
        std::vector<const reco::Track*> trackPtrs(n);
        for(unsigned int i = 0; i < n; i++)
                trackPtrs[i] = &*tracks[i];

        return (*this)(&trackPtrs[0], n);
}

bool
V0Filter::operator () (const reco::Track *tracks, unsigned int n) const
{
        std::vector<const reco::Track*> trackPtrs(n);
        for(unsigned int i = 0; i < n; i++)
                trackPtrs[i] = &tracks[i];

        return (*this)(&trackPtrs[0], n);
}