IdealHelixParameters Class Reference

#include <IdealHelixParameters.h>

Public Member Functions
math::XYZVector	GetCircleCenter () const
math::XYZVector	GetMomentumAtTangentPoint () const
float	GetRotationAngle () const
math::XYZVector	GetTangentPoint () const
float	GetTransverseIPAtTangent () const
	IdealHelixParameters ()
bool	isTangentPointDistanceLessThan (float rmax, const reco::Track *track, const math::XYZVector &refPoint)
void	setData (const reco::Track *track, const math::XYZVector &refPoint=math::XYZVector(0, 0, 0))
void	setData (const reco::Track *track, const math::XYZPoint &ref)
void	setMagnField (const MagneticField *magnField)
	~IdealHelixParameters ()

Private Member Functions
void	calculate ()
void	evalCircleCenter ()
void	evalMomentumatTangentPoint ()
void	evalTangentPoint ()

Private Attributes
math::XYZVector	_circleCenter
const MagneticField *	_magnField
math::XYZVector	_MomentumAtTangentPoint
float	_radius
math::XYZVector	_refPoint
float	_rotationAngle
math::XYZVector	_tangentPoint
const reco::Track *	_track
float	_transverseIP

Detailed Description

Definition at line 21 of file IdealHelixParameters.h.

Constructor & Destructor Documentation

IdealHelixParameters::IdealHelixParameters ( )

inline

Definition at line 25 of file IdealHelixParameters.h.

                       :
  _magnField(0),_track(0),
    _refPoint               (math::XYZVector(0,0,0)),
    _tangentPoint           (math::XYZVector(0,0,0)),
    _MomentumAtTangentPoint(math::XYZVector(0,0,0)){};

IdealHelixParameters::~IdealHelixParameters ( )

inline

Definition at line 30 of file IdealHelixParameters.h.

{};

Member Function Documentation

void IdealHelixParameters::calculate ( )

private

Definition at line 25 of file IdealHelixParameters.cc.

References _refPoint, _track, evalCircleCenter(), evalMomentumatTangentPoint(), evalTangentPoint(), reco::Track::innerDetId(), reco::Track::innerMomentum(), reco::Track::innerPosition(), and LogDebug.

Referenced by setData().

           {

  LogDebug("IdealHelixParameters")
    << "[IdealHelixParameters] " 
    << "\n\t "<< "refPoint \t" <<_refPoint
    << "\n\t "<< "innerDetid    \t" << _track->innerDetId()
    << "\n\t "<< "innerMomentum \t" << _track->innerMomentum()
    << "\n\t "<< "innerPosition \t" << _track->innerPosition();

  evalCircleCenter();
  
  evalTangentPoint();

  evalMomentumatTangentPoint();
  

  /* DEBUG
    math::XYZVector _checkMomentumAtTangentoPoint (
    cos_angle*innerMomentum.x()+sin_angle*innerMomentum.y(), 
    -1*sin_angle*innerMomentum.x()+cos_angle*innerMomentum.y(), 
    innerMomentum.z()
    );
    math::XYZVector cp_xy(_checkMomentumAtTangentoPoint.x(),_checkMomentumAtTangentoPoint.y(),0);
    float _checktransverseIP = (r_xy.Cross(cp_xy)).z()/cp_xy.rho();

    ss 
    << "\n\t "<< "_checkMomentumAtTangentoPoint \t" <<_checkMomentumAtTangentoPoint
    << "\n\t "<< "_checktransverseIP \t" <<_checktransverseIP;
  */

}

void IdealHelixParameters::evalCircleCenter ( )

private

Definition at line 58 of file IdealHelixParameters.cc.

References _circleCenter, _magnField, _radius, _track, reco::TrackBase::charge(), funct::cos(), reco::Track::innerMomentum(), reco::Track::innerPosition(), LogDebug, phi, and funct::sin().

Referenced by calculate().

                  {
  GlobalPoint  innerPos(_track->innerPosition().x(),_track->innerPosition().y(),_track->innerPosition().z());
  GlobalVector innerMom(_track->innerMomentum().x(),_track->innerMomentum().y(),_track->innerMomentum().z());

  GlobalTrajectoryParameters globalTrajParam(
                         innerPos,
                         innerMom,
                         _track->charge(),
                         _magnField
                         );

  _radius = 1./fabs(globalTrajParam.transverseCurvature());
  float phi = innerMom.phi();

  //eval Center of the Circumference passing in track->innserPosition
  float Xc = innerPos.x() + _track->charge()* _radius * sin(phi);
  float Yc = innerPos.y() - _track->charge()* _radius * cos(phi);

  
  _circleCenter.SetXYZ(Xc,Yc,innerPos.z());  //NB Z component is useless

  LogDebug("IdealHelixParameters")
      << "\n\t "<< "circle center \t" <<_circleCenter
      << "\n\t "<< "radius "          <<_radius; 

}

void IdealHelixParameters::evalMomentumatTangentPoint ( )

private

Definition at line 87 of file IdealHelixParameters.cc.

References _circleCenter, _MomentumAtTangentPoint, _rotationAngle, _tangentPoint, _track, _transverseIP, reco::Track::innerMomentum(), reco::Track::innerPosition(), and LogDebug.

Referenced by calculate().

                            {
  
  if(_tangentPoint.r()==0){
    _MomentumAtTangentPoint = math::XYZVector(0.,0.,0.);
    return;
  }

  math::XYZVector innerPosition(_track->innerPosition().X(),_track->innerPosition().Y(),_track->innerPosition().Z());
  math::XYZVector innerMomentum(_track->innerMomentum());


  math::XYZVector pCi=innerPosition-_circleCenter;
  math::XYZVector pCT=_tangentPoint-_circleCenter;

  math::XYZVector pCi_xy(pCi.x(),pCi.y(),0);
  math::XYZVector pCT_xy(pCT.x(),pCT.y(),0);
  
  float cos_angle = pCi_xy.Dot(pCT_xy)/pCi_xy.rho()/pCT_xy.rho();
  float sin_angle = pCi_xy.Cross(pCT_xy).z()/pCi_xy.rho()/pCT_xy.rho();


  _MomentumAtTangentPoint = math::XYZVector(
                        cos_angle*innerMomentum.x()-sin_angle*innerMomentum.y(), 
                        sin_angle*innerMomentum.x()+cos_angle*innerMomentum.y(), 
                        innerMomentum.z()
                        );

  math::XYZVector r_(_tangentPoint.x(),_tangentPoint.y(),0);
  math::XYZVector p_(_MomentumAtTangentPoint.x(),_MomentumAtTangentPoint.y(),0);
  
  _transverseIP = (r_.x()*p_.y()-r_.y()*p_.x())/p_.rho()/r_.rho();
  _rotationAngle=atan(sin_angle/cos_angle);


  
  LogDebug("IdealHelixParameters")  << "\n\t "<< "_MomentumAtTangentPoint \t" <<_MomentumAtTangentPoint
                << "\n\t "<< "sin_angle \t" <<sin_angle << " angle \t" <<asin(sin_angle)
                << "\n\t "<< "cos_angle \t" <<cos_angle << " angle \t" <<acos(cos_angle)
                << "\n\t "<< "_rotationAngle \t" <<_rotationAngle
                << "\n\t "<< "_transverseIP \t" <<_transverseIP
                << "\n\t "<< " check similitude pz/pt "<< _track->innerMomentum().z()/_track->innerMomentum().rho() << " pZ/pRho " << innerPosition.z()/innerPosition.rho();
}

void IdealHelixParameters::evalTangentPoint ( )

private

Definition at line 132 of file IdealHelixParameters.cc.

References _circleCenter, _radius, _refPoint, _tangentPoint, _track, reco::Track::innerMomentum(), reco::Track::innerPosition(), prof2calltree::l, LogDebug, rho, and mathSSE::sqrt().

Referenced by calculate().

                  {

  math::XYZVector innerPosition(_track->innerPosition().X(),_track->innerPosition().Y(),_track->innerPosition().Z());

  math::XYZVector vL = _circleCenter-_refPoint;
  float l = vL.rho();

  if(l<_radius){
    //refpoint is inside the circle
    _tangentPoint.SetXYZ(0.,0.,0.);
    return;
  }

  float sin_alpha = _radius/l;

  //there are two possible tangents, with Point of tangence T1 and T2, and same distance T from _refPoint 
  float T=sqrt(l*l-_radius*_radius);

  math::XYZVector vLperp(-vL.y(),vL.x(),0); //NB: z component not correct
  math::XYZVector tmpT1 = (1-sin_alpha*sin_alpha)*vL + T/l*sin_alpha*vLperp;
  math::XYZVector tmpT2 = (1-sin_alpha*sin_alpha)*vL - T/l*sin_alpha*vLperp;

  if( (tmpT1-innerPosition).rho()<(tmpT2-innerPosition).rho())
    _tangentPoint=tmpT1+_refPoint;
  else
    _tangentPoint=tmpT2+_refPoint;

  //Fix the Z component
  _tangentPoint.SetZ( (_tangentPoint.rho()-_refPoint.rho()) * (_track->innerMomentum().z()/_track->innerMomentum().rho()) + _refPoint.z() );

  LogDebug("IdealHelixParameters")<< "\n\t "<< "tangent Point \t" <<_tangentPoint;
}

math::XYZVector IdealHelixParameters::GetCircleCenter ( ) const

inline

Definition at line 38 of file IdealHelixParameters.h.

References _circleCenter.

{return _circleCenter;}

math::XYZVector IdealHelixParameters::GetMomentumAtTangentPoint ( ) const

inline

Definition at line 40 of file IdealHelixParameters.h.

References _MomentumAtTangentPoint.

Referenced by PhotonConversionTrajectorySeedProducerFromSingleLegAlgo::inspectTrack().

{return _MomentumAtTangentPoint;}

float IdealHelixParameters::GetRotationAngle ( ) const

inline

Definition at line 42 of file IdealHelixParameters.h.

References _rotationAngle.

{return _rotationAngle;}

math::XYZVector IdealHelixParameters::GetTangentPoint ( ) const

inline

Definition at line 39 of file IdealHelixParameters.h.

References _tangentPoint.

Referenced by PhotonConversionTrajectorySeedProducerFromSingleLegAlgo::inspectTrack(), isTangentPointDistanceLessThan(), and PhotonConversionTrajectorySeedProducerFromSingleLegAlgo::rejectTrack().

{return _tangentPoint;}

float IdealHelixParameters::GetTransverseIPAtTangent ( ) const

inline

Definition at line 41 of file IdealHelixParameters.h.

References _transverseIP.

{return _transverseIP;}

bool IdealHelixParameters::isTangentPointDistanceLessThan	(	float	rmax,
		const reco::Track *	track,
		const math::XYZVector &	refPoint
	)

Definition at line 166 of file IdealHelixParameters.cc.

References GetTangentPoint(), alignCSCRings::r, rho, and setData().

Referenced by ConversionTrackProducer::produce().

                                                                                                 {

  setData(track,refPoint);   
  if(GetTangentPoint().r()==0){
    //this case means a null results on the IdealHelixParameters side
    return true;
  }
      
  if(GetTangentPoint().rho()<rMax){
        //this case means a track that has the tangent point nearby the primary vertex
        // if the track is primary, this number tends to be the primary vertex itself
        //Rejecting all the potential photon conversions having a "vertex" inside the beampipe
        //We should not miss too much, seen that the conversions at the beam pipe are the better reconstructed
    return true;
  }

  return false;
}

void IdealHelixParameters::setData	(	const reco::Track *	track,
		const math::XYZVector &	refPoint = math::XYZVector(0,0,0)
	)

Definition at line 9 of file IdealHelixParameters.cc.

References _refPoint, _track, calculate(), and alignCSCRings::r.

Referenced by PhotonConversionTrajectorySeedProducerFromSingleLegAlgo::inspectTrack(), isTangentPointDistanceLessThan(), PhotonConversionTrajectorySeedProducerFromSingleLegAlgo::rejectTrack(), and setData().

                                                               {

  if(track!=0 && _track!=track){
    _track=track;
    _refPoint=refPoint;
    calculate();
  }

  if((refPoint-_refPoint).r()!=0){
    _refPoint=refPoint;
    calculate();
  }
}

void IdealHelixParameters::setData	(	const reco::Track *	track,
		const math::XYZPoint &	ref
	)

Definition at line 4 of file IdealHelixParameters.cc.

References setData().

                                                         {
  setData(track,math::XYZVector(ref.x(),ref.y(),ref.z())); 
}

void IdealHelixParameters::setMagnField ( const MagneticField *  magnField )

inline

Definition at line 32 of file IdealHelixParameters.h.

References _magnField.

Referenced by PhotonConversionTrajectorySeedProducerFromSingleLegAlgo::analyze(), and ConversionTrackProducer::produce().

{_magnField=magnField;}

Member Data Documentation

math::XYZVector IdealHelixParameters::_circleCenter

private

Definition at line 54 of file IdealHelixParameters.h.

Referenced by evalCircleCenter(), evalMomentumatTangentPoint(), evalTangentPoint(), and GetCircleCenter().

const MagneticField* IdealHelixParameters::_magnField

private

Definition at line 51 of file IdealHelixParameters.h.

Referenced by evalCircleCenter(), and setMagnField().

math::XYZVector IdealHelixParameters::_MomentumAtTangentPoint

private

Definition at line 57 of file IdealHelixParameters.h.

Referenced by evalMomentumatTangentPoint(), and GetMomentumAtTangentPoint().

float IdealHelixParameters::_radius

private

Definition at line 53 of file IdealHelixParameters.h.

Referenced by evalCircleCenter(), and evalTangentPoint().

math::XYZVector IdealHelixParameters::_refPoint

private

Definition at line 55 of file IdealHelixParameters.h.

Referenced by calculate(), evalTangentPoint(), and setData().

float IdealHelixParameters::_rotationAngle

private

Definition at line 59 of file IdealHelixParameters.h.

Referenced by evalMomentumatTangentPoint(), and GetRotationAngle().

math::XYZVector IdealHelixParameters::_tangentPoint

private

Definition at line 56 of file IdealHelixParameters.h.

Referenced by evalMomentumatTangentPoint(), evalTangentPoint(), and GetTangentPoint().

const reco::Track* IdealHelixParameters::_track

private

Definition at line 52 of file IdealHelixParameters.h.

Referenced by calculate(), evalCircleCenter(), evalMomentumatTangentPoint(), evalTangentPoint(), and setData().

float IdealHelixParameters::_transverseIP

private

Definition at line 58 of file IdealHelixParameters.h.

Referenced by evalMomentumatTangentPoint(), and GetTransverseIPAtTangent().