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InvariantMassFromVertex Class Reference

#include <InvariantMassFromVertex.h>

List of all members.

Public Types

typedef ROOT::Math::PxPyPzMVector LorentzVector

Public Member Functions

Measurement1D invariantMass (const CachingVertex< 5 > &vertex, const std::vector< double > &masses) const
Measurement1D invariantMass (const CachingVertex< 5 > &vertex, const double mass) const
GlobalVector momentum (const CachingVertex< 5 > &vertex) const
LorentzVector p4 (const CachingVertex< 5 > &vertex, const std::vector< double > &masses) const
LorentzVector p4 (const CachingVertex< 5 > &vertex, const double mass) const

Private Types

typedef
ReferenceCountingPointer
< LinearizedTrackState< 5 > > 
RefCountedLinearizedTrackState
typedef
ReferenceCountingPointer
< RefittedTrackState< 5 > > 
RefCountedRefittedTrackState
typedef
ReferenceCountingPointer
< VertexTrack< 5 > > 
RefCountedVertexTrack

Private Member Functions

double uncertainty (const LorentzVector &p4, const CachingVertex< 5 > &vertex, const std::vector< double > &masses) const

Detailed Description

Class building a resulting output tree out of the information provided by KinematicParticleVertexFitter.

Definition at line 20 of file InvariantMassFromVertex.h.


Member Typedef Documentation

typedef ROOT::Math::PxPyPzMVector InvariantMassFromVertex::LorentzVector

Definition at line 23 of file InvariantMassFromVertex.h.

Definition at line 49 of file InvariantMassFromVertex.h.

Definition at line 50 of file InvariantMassFromVertex.h.

Definition at line 48 of file InvariantMassFromVertex.h.


Member Function Documentation

Measurement1D InvariantMassFromVertex::invariantMass ( const CachingVertex< 5 > &  vertex,
const std::vector< double > &  masses 
) const

Definition at line 71 of file InvariantMassFromVertex.cc.

References gather_cfg::cout, LogDebug, p4(), CachingVertex< N >::tkToTkCovarianceIsAvailable(), CachingVertex< N >::tracks(), and uncertainty().

Referenced by invariantMass().

{

  // Check that tkToTkCovarianceIsAvailable
  if (!vertex.tkToTkCovarianceIsAvailable()) {
    LogDebug("InvariantMassFromVertex")
        << "Fit failed: vertex has not been smoothed\n";
    return Measurement1D(0.,0.);
  }
  if (vertex.tracks().size() != masses.size()) {
    LogDebug("InvariantMassFromVertex")
        << "Vector of masses does not have the same size as tracks in vertex\n";
    return Measurement1D(0.,0.);
  }

  LorentzVector totalP4 = p4(vertex, masses);
  double u = uncertainty(totalP4, vertex, masses);
  std::cout << u<<std::endl;
  return Measurement1D(totalP4.M(), u );

}
Measurement1D InvariantMassFromVertex::invariantMass ( const CachingVertex< 5 > &  vertex,
const double  mass 
) const

Definition at line 64 of file InvariantMassFromVertex.cc.

References invariantMass(), and CachingVertex< N >::tracks().

{
  return invariantMass(vertex, std::vector<double>(vertex.tracks().size(), mass));
}
GlobalVector InvariantMassFromVertex::momentum ( const CachingVertex< 5 > &  vertex) const

Definition at line 42 of file InvariantMassFromVertex.cc.

References LogDebug, CachingVertex< N >::tkToTkCovarianceIsAvailable(), and CachingVertex< N >::tracks().

Referenced by p4().

{
 GlobalVector momentum_;

  // Check that tkToTkCovarianceIsAvailable
  if (!vertex.tkToTkCovarianceIsAvailable()) {
    LogDebug("InvariantMassFromVertex")
        << "Fit failed: vertex has not been smoothed\n";
   return momentum_;
  }

  std::vector<RefCountedVertexTrack> refTracks = vertex.tracks();
  std::vector<RefCountedVertexTrack>::const_iterator i_s = refTracks.begin();

  for( ;i_s !=refTracks.end() ; ++i_s) {
    momentum_ += (**i_s).refittedState()->freeTrajectoryState().momentum();
  } 
  return momentum_;

}
InvariantMassFromVertex::LorentzVector InvariantMassFromVertex::p4 ( const CachingVertex< 5 > &  vertex,
const double  mass 
) const

four-momentum Lorentz vector

Definition at line 5 of file InvariantMassFromVertex.cc.

References p4(), and CachingVertex< N >::tracks().

{
  return p4(vertex, std::vector<double>(vertex.tracks().size(), mass));
}
InvariantMassFromVertex::LorentzVector InvariantMassFromVertex::p4 ( const CachingVertex< 5 > &  vertex,
const std::vector< double > &  masses 
) const

four-momentum Lorentz vector

Definition at line 11 of file InvariantMassFromVertex.cc.

References LogDebug, momentum(), CachingVertex< N >::tkToTkCovarianceIsAvailable(), CachingVertex< N >::tracks(), PV3DBase< T, PVType, FrameType >::x(), PV3DBase< T, PVType, FrameType >::y(), and PV3DBase< T, PVType, FrameType >::z().

Referenced by invariantMass(), and p4().

{

  LorentzVector totalP4;

  // Check that tkToTkCovarianceIsAvailable
  if (!vertex.tkToTkCovarianceIsAvailable()) {
    LogDebug("InvariantMassFromVertex")
        << "Fit failed: vertex has not been smoothed\n";
    return totalP4;
  }

  if (vertex.tracks().size() != masses.size()) {
    LogDebug("InvariantMassFromVertex")
        << "Vector of masses does not have the same size as tracks in vertex\n";
    return totalP4;
  }


  std::vector<RefCountedVertexTrack> refTracks = vertex.tracks();
  std::vector<RefCountedVertexTrack>::const_iterator i_s = refTracks.begin();
  std::vector<double>::const_iterator i_m = masses.begin();

  for( ;i_s !=refTracks.end(), i_m != masses.end(); ++i_s, ++i_m) {
    GlobalVector momentum = (**i_s).refittedState()->freeTrajectoryState().momentum();
    totalP4 += LorentzVector(momentum.x(), momentum.y(), momentum.z(), *i_m);
  } 
  return totalP4;
}
double InvariantMassFromVertex::uncertainty ( const LorentzVector p4,
const CachingVertex< 5 > &  vertex,
const std::vector< double > &  masses 
) const [private]

Definition at line 96 of file InvariantMassFromVertex.cc.

References a, funct::cos(), Exception, phi, CachingVertex< N >::position(), rho, funct::sin(), findQualityFiles::size, mathSSE::sqrt(), funct::tan(), theta(), CachingVertex< N >::tkToTkCovariance(), CachingVertex< N >::tracks(), and z.

Referenced by invariantMass().

{
  std::vector<RefCountedVertexTrack> refTracks = vertex.tracks();
  int size = refTracks.size();
  AlgebraicMatrix cov(3*size,3*size);
  AlgebraicMatrix jac(1,3*size);

  double energy_total = totalP4.E();

  std::vector<RefCountedVertexTrack>::const_iterator rt_i = refTracks.begin();
  std::vector<double>::const_iterator i_m = masses.begin();

  int i_int = 0;
  for( ;rt_i !=refTracks.end(), i_m != masses.end(); ++rt_i, ++i_m) {

    double a;
    AlgebraicVector5 param = (**rt_i).refittedState()->parameters(); // rho, theta, phi,tr_im, z_im
    double rho = param[0];
    double theta = param[1];
    double phi = param[2];
    double mass = *i_m;

    if ((**rt_i).linearizedTrack()->charge()!=0) {
      a = -(**rt_i).refittedState()->freeTrajectoryState().parameters().magneticFieldInInverseGeV(vertex.position()).z()
                * (**rt_i).refittedState()->freeTrajectoryState().parameters ().charge();
      if (a==0.) throw cms::Exception("InvariantMassFromVertex", "Field is 0");
    } else {
      a = 1;
    }

    double energy_local  = sqrt(a*a/(rho*rho)*(1+1/(tan(theta)*tan(theta)))  + mass*mass);

    jac(1,i_int*3+1) = (-(energy_total/energy_local*a*a/(rho*rho*rho*sin(theta)*sin(theta)) )
                  + totalP4.X()*a/(rho*rho)*cos(phi) + totalP4.Y()*a/(rho*rho)*sin(phi)
                  + totalP4.Z()*a/(rho*rho*tan(theta)) )/totalP4.M();   //dm / drho

    jac(1,i_int*3+2) = (-(energy_total/energy_local*a*a/(rho*rho*sin(theta)*sin(theta)*tan(theta)) )
                  + totalP4.Z()*a/(rho*sin(theta)*sin(theta)) )/totalP4.M();//dm d theta

    jac(1,i_int*3+3) = ( totalP4.X()*sin(phi) - totalP4.Y()*cos(phi) )*a/(rho*totalP4.M());     //dm/dphi

    // momentum corellatons: diagonal elements of the matrix
    cov.sub(i_int*3 + 1, i_int*3 + 1,asHepMatrix<6>((**rt_i).fullCovariance()).sub(4,6));

    //off diagonal elements: track momentum - track momentum corellations

    int j_int = 0;
    for(std::vector<RefCountedVertexTrack>::const_iterator rt_j = refTracks.begin(); rt_j != refTracks.end(); rt_j++) {
      if(i_int < j_int) {
        AlgebraicMatrix i_k_cov_m = asHepMatrix<3,3>(vertex.tkToTkCovariance((*rt_i),(*rt_j)));
        cov.sub(i_int*3 + 1, j_int*3 + 1,i_k_cov_m);
        cov.sub(j_int*3 + 1, i_int*3 + 1,i_k_cov_m.T());
      }
      j_int++;
    }
    i_int++;
  }
//   std::cout<<"jac"<<jac<<std::endl;
//   std::cout<<"cov"<<cov<<std::endl;
//   std::cout << "final result"<<(jac*cov*jac.T())<<std::endl;

  return sqrt((jac*cov*jac.T())(1,1));
}