TrackKinematicStatePropagator Class Reference

#include <TrackKinematicStatePropagator.h>

Inheritance diagram for TrackKinematicStatePropagator:

Public Member Functions
virtual KinematicStatePropagator *	clone () const
virtual std::pair < HelixBarrelPlaneCrossingByCircle, BoundPlane::BoundPlanePointer >	planeCrossing (const FreeTrajectoryState &par, const GlobalPoint &point) const
virtual KinematicState	propagateToTheTransversePCA (const KinematicState &state, const GlobalPoint &referencePoint) const
	TrackKinematicStatePropagator ()
virtual	~TrackKinematicStatePropagator ()
Public Member Functions inherited from KinematicStatePropagator
	KinematicStatePropagator ()
virtual	~KinematicStatePropagator ()

Private Types
typedef Point3DBase< double, GlobalTag >	GlobalPointDouble
typedef Vector3DBase< double, GlobalTag >	GlobalVectorDouble

Private Member Functions
virtual KinematicState	propagateToTheTransversePCACharged (const KinematicState &state, const GlobalPoint &referencePoint) const
virtual KinematicState	propagateToTheTransversePCANeutral (const KinematicState &state, const GlobalPoint &referencePoint) const

Detailed Description

Propagator for TransientTrack based KinematicStates. Does not include the material.

Definition at line 18 of file TrackKinematicStatePropagator.h.

Member Typedef Documentation

typedef Point3DBase< double, GlobalTag> TrackKinematicStatePropagator::GlobalPointDouble

private

Definition at line 53 of file TrackKinematicStatePropagator.h.

typedef Vector3DBase< double, GlobalTag> TrackKinematicStatePropagator::GlobalVectorDouble

private

Definition at line 54 of file TrackKinematicStatePropagator.h.

Constructor & Destructor Documentation

TrackKinematicStatePropagator::TrackKinematicStatePropagator ( )

inline

Definition at line 22 of file TrackKinematicStatePropagator.h.

Referenced by clone().

{}

virtual TrackKinematicStatePropagator::~TrackKinematicStatePropagator ( )

inlinevirtual

Definition at line 24 of file TrackKinematicStatePropagator.h.

{}

Member Function Documentation

virtual KinematicStatePropagator* TrackKinematicStatePropagator::clone ( void  ) const

inlinevirtual

Clone method reimplemented from abstract class

Implements KinematicStatePropagator.

Definition at line 40 of file TrackKinematicStatePropagator.h.

References TrackKinematicStatePropagator().

 {return new TrackKinematicStatePropagator(*this);}

pair< HelixBarrelPlaneCrossingByCircle, BoundPlane::BoundPlanePointer > TrackKinematicStatePropagator::planeCrossing ( const FreeTrajectoryState &  par, const GlobalPoint &  point  ) const

virtual

Definition at line 23 of file TrackKinematicStatePropagator.cc.

References anyDirection, BoundPlane::build(), FreeTrajectoryState::charge(), MagneticField::inInverseGeV(), GlobalTrajectoryParameters::magneticField(), FreeTrajectoryState::momentum(), FreeTrajectoryState::parameters(), pos, FreeTrajectoryState::position(), makeMuonMisalignmentScenario::rot, FreeTrajectoryState::transverseCurvature(), Vector3DBase< T, FrameTag >::unit(), X, PV3DBase< T, PVType, FrameType >::x(), PV3DBase< T, PVType, FrameType >::y(), and PV3DBase< T, PVType, FrameType >::z().

{
 GlobalPoint inPos = state.position();
 GlobalVector inMom = state.momentum();
 double kappa = state.transverseCurvature();
 double fac = 1./state.charge()/state.parameters().magneticField().inInverseGeV(point).z();
 
 GlobalVectorDouble xOrig2Centre = GlobalVectorDouble(fac * inMom.y(), -fac * inMom.x(), 0.);
 GlobalVectorDouble xOrigProj = GlobalVectorDouble(inPos.x(), inPos.y(), 0.);
 GlobalVectorDouble xRefProj = GlobalVectorDouble(point.x(), point.y(), 0.);
 GlobalVectorDouble deltax = xRefProj-xOrigProj-xOrig2Centre;
 GlobalVectorDouble ndeltax = deltax.unit();
  
 PropagationDirection direction = anyDirection;
 Surface::PositionType pos(point);
  
// Need to define plane with orientation as the ImpactPointSurface
 GlobalVector X(ndeltax.x(), ndeltax.y(), ndeltax.z());
 GlobalVector Y(0.,0.,1.);
 Surface::RotationType rot(X,Y);
 BoundPlane::BoundPlanePointer plane = BoundPlane::build(pos,rot,OpenBounds());
 HelixBarrelPlaneCrossingByCircle 
   planeCrossing(HelixPlaneCrossing::PositionType(inPos.x(), inPos.y(), inPos.z()),
         HelixPlaneCrossing::DirectionType(inMom.x(), inMom.y(), inMom.z()), 
         kappa, direction);
 return std::pair<HelixBarrelPlaneCrossingByCircle,BoundPlane::BoundPlanePointer>(planeCrossing,plane);
}

KinematicState TrackKinematicStatePropagator::propagateToTheTransversePCA ( const KinematicState &  state, const GlobalPoint &  referencePoint  ) const

virtual

Propagation to the point of closest approach in transverse plane to the given point

Implements KinematicStatePropagator.

Definition at line 13 of file TrackKinematicStatePropagator.cc.

References KinematicState::particleCharge().

{
 if( state.particleCharge() == 0. ) {
    return propagateToTheTransversePCANeutral(state, referencePoint);
  } else {
    return propagateToTheTransversePCACharged(state, referencePoint);
  }
}

KinematicState TrackKinematicStatePropagator::propagateToTheTransversePCACharged ( const KinematicState &  state, const GlobalPoint &  referencePoint  ) const

privatevirtual

Internal private methods, distinguishing between the propagation of neutrals and propagation of cahrged tracks.

Definition at line 55 of file TrackKinematicStatePropagator.cc.

References HelixBarrelPlaneCrossingByCircle::direction(), KinematicState::freeTrajectoryState(), KinematicState::globalMomentum(), KinematicState::globalPosition(), JacobianCurvilinearToCartesian::jacobian(), KinematicState::kinematicParametersError(), LogDebug, PV3DBase< T, PVType, FrameType >::mag(), KinematicState::magneticField(), scaleCards::mass, KinematicState::mass(), KinematicParametersError::matrix(), KinematicState::particleCharge(), HelixBarrelPlaneCrossingByCircle::pathLength(), HelixBarrelPlaneCrossingByCircle::position(), alignCSCRings::s, PV3DBase< T, PVType, FrameType >::x(), Basic3DVector< T >::x(), Basic3DVector< T >::y(), and Basic3DVector< T >::z().

{
//first use the existing FTS propagator to obtain parameters at PCA
//in transverse plane to the given point

//final parameters and covariance
  AlgebraicVector7 par;
  AlgebraicSymMatrix77 cov;
    
//initial parameters as class and vectors:  
  GlobalTrajectoryParameters inPar(state.globalPosition(),state.globalMomentum(), 
        state.particleCharge(), state.magneticField());
  ParticleMass mass = state.mass();                           
  GlobalVector inMom = state.globalMomentum();                            
  
//making a free trajectory state and looking 
//for helix barrel plane crossing  
  FreeTrajectoryState fState = state.freeTrajectoryState();     
  GlobalPoint iP = referencePoint;                    
  std::pair<HelixBarrelPlaneCrossingByCircle, BoundPlane::BoundPlanePointer> cros = planeCrossing(fState,iP);      
  
  HelixBarrelPlaneCrossingByCircle planeCrossing = cros.first; 
  BoundPlane::BoundPlanePointer plane = cros.second;
  std::pair<bool,double> propResult = planeCrossing.pathLength(*plane);
  if ( !propResult.first ) {
    LogDebug("RecoVertex/TrackKinematicStatePropagator") 
     << "Propagation failed! State is invalid\n";
    return  KinematicState();
  }
  double s = propResult.second;
  
  HelixPlaneCrossing::PositionType xGen = planeCrossing.position(s);
  GlobalPoint nPosition(xGen.x(),xGen.y(),xGen.z());
  HelixPlaneCrossing::DirectionType pGen = planeCrossing.direction(s);
  pGen *= inMom.mag()/pGen.mag();
  GlobalVector nMomentum(pGen.x(),pGen.y(),pGen.z()); 
  par(0) = nPosition.x();
  par(1) = nPosition.y();
  par(2) = nPosition.z();
  par(3) = nMomentum.x();
  par(4) = nMomentum.y();
  par(5) = nMomentum.z();
  par(6) = mass;
  
//covariance matrix business  
//elements of 7x7 covariance matrix responcible for the mass and
//mass - momentum projections corellations do change under such a transformation:
//special Jacobian needed  
  GlobalTrajectoryParameters fPar(nPosition, nMomentum, state.particleCharge(),
                state.magneticField());
                                                      
  JacobianCartesianToCurvilinear cart2curv(inPar);
  JacobianCurvilinearToCartesian curv2cart(fPar);
  
  AlgebraicMatrix67 ca2cu;
  AlgebraicMatrix76 cu2ca;
  ca2cu.Place_at(cart2curv.jacobian(),0,0);
  cu2ca.Place_at(curv2cart.jacobian(),0,0);
  ca2cu(5,6) = 1;  
  cu2ca(6,5) = 1;

//now both transformation jacobians: cartesian to curvilinear and back are done
//We transform matrix to curv frame, then propagate it and translate it back to
//cartesian frame.  
  AlgebraicSymMatrix66 cov1 = ROOT::Math::Similarity(ca2cu, state.kinematicParametersError().matrix());

//propagation jacobian
  AnalyticalCurvilinearJacobian prop(inPar,nPosition,nMomentum,s);
  AlgebraicMatrix66 pr;
  pr(5,5) = 1;
  pr.Place_at(prop.jacobian(),0,0);

//transportation
  AlgebraicSymMatrix66 cov2 = ROOT::Math::Similarity(pr, cov1);
  
//now geting back to 7-parametrization from curvilinear
  cov = ROOT::Math::Similarity(cu2ca, cov2);
  
//return parameters as a kiematic state  
  KinematicParameters resPar(par);
  KinematicParametersError resEr(cov);
  return  KinematicState(resPar,resEr,state.particleCharge(), state.magneticField()); 
 }

KinematicState TrackKinematicStatePropagator::propagateToTheTransversePCANeutral ( const KinematicState &  state, const GlobalPoint &  referencePoint  ) const

privatevirtual

Definition at line 140 of file TrackKinematicStatePropagator.cc.

References funct::cos(), KinematicState::freeTrajectoryState(), KinematicState::globalMomentum(), KinematicState::globalPosition(), JacobianCurvilinearToCartesian::jacobian(), KinematicState::kinematicParametersError(), KinematicState::magneticField(), KinematicState::mass(), KinematicParametersError::matrix(), KinematicState::particleCharge(), phi, alignCSCRings::s, funct::sin(), funct::tan(), theta(), PV3DBase< T, PVType, FrameType >::x(), PV3DBase< T, PVType, FrameType >::y(), and PV3DBase< T, PVType, FrameType >::z().

{
//new parameters vector and covariance:
 AlgebraicVector7 par;
 AlgebraicSymMatrix77 cov;
 
 //AlgebraicVector7 inStatePar = state.kinematicParameters().vector();
 GlobalTrajectoryParameters inPar(state.globalPosition(),state.globalMomentum(), 
        state.particleCharge(), state.magneticField());
 
//first making a free trajectory state and propagating it according
//to the algorithm provided by Thomas Speer and Wolfgang Adam 
 FreeTrajectoryState fState = state.freeTrajectoryState();
  
 GlobalPoint xvecOrig = fState.position();
 double phi = fState.momentum().phi();
 double theta = fState.momentum().theta();
 double xOrig = xvecOrig.x();
 double yOrig = xvecOrig.y();
 double zOrig = xvecOrig.z();
 double xR = referencePoint.x();
 double yR = referencePoint.y();

 double s2D = (xR - xOrig)  * cos(phi) + (yR - yOrig)  * sin(phi);
 double s = s2D / sin(theta);
 double xGen = xOrig + s2D*cos(phi);
 double yGen = yOrig + s2D*sin(phi);
 double zGen = zOrig + s2D/tan(theta);
 GlobalPoint xPerigee = GlobalPoint(xGen, yGen, zGen);

//new parameters
 GlobalVector pPerigee = fState.momentum();
 par(0) = xPerigee.x();
 par(1) = xPerigee.y(); 
 par(2) = xPerigee.z(); 
 par(3) = pPerigee.x(); 
 par(4) = pPerigee.y(); 
 par(5) = pPerigee.z(); 
 // par(6) = inStatePar(7);
 par(6) = state.mass();

//covariance matrix business:
//everything lake it was before: jacobains are smart enouhg to 
//distinguish between neutral and charged states themselves

 GlobalTrajectoryParameters fPar(xPerigee, pPerigee, state.particleCharge(),
                state.magneticField());

 JacobianCartesianToCurvilinear cart2curv(inPar);
 JacobianCurvilinearToCartesian curv2cart(fPar);
  
  AlgebraicMatrix67 ca2cu;
  AlgebraicMatrix76 cu2ca;
  ca2cu.Place_at(cart2curv.jacobian(),0,0);
  cu2ca.Place_at(curv2cart.jacobian(),0,0);
  ca2cu(5,6) = 1;  
  cu2ca(6,5) = 1;

//now both transformation jacobians: cartesian to curvilinear and back are done
//We transform matrix to curv frame, then propagate it and translate it back to
//cartesian frame.  
  AlgebraicSymMatrix66 cov1 = ROOT::Math::Similarity(ca2cu, state.kinematicParametersError().matrix());

//propagation jacobian
  AnalyticalCurvilinearJacobian prop(inPar,xPerigee,pPerigee,s);
  AlgebraicMatrix66 pr;
  pr(5,5) = 1;
  pr.Place_at(prop.jacobian(),0,0);
  
//transportation
  AlgebraicSymMatrix66 cov2 = ROOT::Math::Similarity(pr, cov1);
  
//now geting back to 7-parametrization from curvilinear
  cov = ROOT::Math::Similarity(cu2ca, cov2);
 
//return parameters as a kiematic state  
 KinematicParameters resPar(par);
 KinematicParametersError resEr(cov);
 return  KinematicState(resPar,resEr,state.particleCharge(), state.magneticField());    
}