MultiTrackMassKinematicConstraint Class Reference

#include <MultiTrackMassKinematicConstraint.h>

Inheritance diagram for MultiTrackMassKinematicConstraint:

Public Member Functions
MultiTrackMassKinematicConstraint *	clone () const override
	MultiTrackMassKinematicConstraint (const ParticleMass &theMass, const unsigned int nbrParticles)
int	numberOfEquations () const override
AlgebraicMatrix	parametersDerivative (const std::vector< KinematicState > &states, const GlobalPoint &point) const override
AlgebraicMatrix	positionDerivative (const std::vector< KinematicState > &states, const GlobalPoint &point) const override
AlgebraicVector	value (const std::vector< KinematicState > &states, const GlobalPoint &point) const override
Public Member Functions inherited from MultiTrackKinematicConstraint
	MultiTrackKinematicConstraint ()
virtual	~MultiTrackKinematicConstraint ()

Private Attributes
const ParticleMass	mass
const unsigned int	nPart

Detailed Description

Constraint to force some of the particles in the fit to have a certain invariant mass.

Definition at line 13 of file MultiTrackMassKinematicConstraint.h.

Constructor & Destructor Documentation

MultiTrackMassKinematicConstraint()

MultiTrackMassKinematicConstraint::MultiTrackMassKinematicConstraint ( const ParticleMass &  theMass, const unsigned int  nbrParticles  )

inline

Constructor

Parameters

theMass	the mass to constrain the states
nbrParticles	the number of particles to use (in case more than that number are present in the fit, the first will be used)

Definition at line 21 of file MultiTrackMassKinematicConstraint.h.

      : mass(theMass), nPart(nbrParticles) {}

Referenced by clone().

Member Function Documentation

clone()

MultiTrackMassKinematicConstraint* MultiTrackMassKinematicConstraint::clone ( void  ) const

inlineoverridevirtual

Implements MultiTrackKinematicConstraint.

Definition at line 52 of file MultiTrackMassKinematicConstraint.h.

{ return new MultiTrackMassKinematicConstraint(*this); }

References MultiTrackMassKinematicConstraint().

numberOfEquations()

int MultiTrackMassKinematicConstraint::numberOfEquations ( ) const

inlineoverridevirtual

Number of equations per track used for the fit

Implements MultiTrackKinematicConstraint.

Definition at line 50 of file MultiTrackMassKinematicConstraint.h.

{ return 1; }

parametersDerivative()

AlgebraicMatrix MultiTrackMassKinematicConstraint::parametersDerivative ( const std::vector< KinematicState > &  states, const GlobalPoint &  point  ) const

overridevirtual

Returns a matrix of derivatives of constraint equations w.r.t. particle parameters

Implements MultiTrackKinematicConstraint.

Definition at line 28 of file MultiTrackMassKinematicConstraint.cc.

                                                                                                        {
  if (states.size() < nPart)
    throw VertexException("MultiTrackMassKinematicConstraint::not enough states given");
 
  AlgebraicMatrix res(1, states.size() * 7, 0);
 
  double sumEnergy = 0, sumPx = 0, sumPy = 0., sumPz = 0.;
 
  double a;
  for (unsigned int i = 0; i < nPart; ++i) {
    a = -states[i].particleCharge() * states[i].magneticField()->inInverseGeV(states[i].globalPosition()).z();
 
    sumEnergy += states[i].kinematicParameters().energy();
    sumPx += states[i].kinematicParameters()(3) - a * (point.y() - states[i].kinematicParameters()(1));
    sumPy += states[i].kinematicParameters()(4) + a * (point.x() - states[i].kinematicParameters()(0));
    sumPz += states[i].kinematicParameters()(5);
  }
 
  for (unsigned int i = 0; i < nPart; ++i) {
    a = -states[i].particleCharge() * states[i].magneticField()->inInverseGeV(states[i].globalPosition()).z();
 
    //x derivatives:
    res(1, 1 + i * 7) = 2 * a * sumPy;
 
    //y derivatives:
    res(1, 2 + i * 7) = -2 * a * sumPx;
 
    //z components:
    res(1, 3 + i * 7) = 0.;
 
    //px components:
    res(1, 4 + i * 7) =
        2 * sumEnergy / states[i].kinematicParameters().energy() * states[i].kinematicParameters()(3) - 2 * sumPx;
 
    //py components:
    res(1, 5 + i * 7) =
        2 * sumEnergy / states[i].kinematicParameters().energy() * states[i].kinematicParameters()(4) - 2 * sumPy;
 
    //pz1 components:
    res(1, 6 + i * 7) =
        2 * sumEnergy / states[i].kinematicParameters().energy() * states[i].kinematicParameters()(5) - 2 * sumPz;
 
    //mass components:
    res(1, 7 + i * 7) =
        2 * states[i].kinematicParameters().mass() * sumEnergy / states[i].kinematicParameters().energy();
  }
  return res;
}

References a, mps_fire::i, nPart, and point.

positionDerivative()

AlgebraicMatrix MultiTrackMassKinematicConstraint::positionDerivative ( const std::vector< KinematicState > &  states, const GlobalPoint &  point  ) const

overridevirtual

Returns a matrix of derivatives of constraint equations w.r.t. vertex position

Implements MultiTrackKinematicConstraint.

Definition at line 78 of file MultiTrackMassKinematicConstraint.cc.

                                                                                                      {
  AlgebraicMatrix res(1, 3, 0);
  if (states.size() < nPart)
    throw VertexException("MultiTrackMassKinematicConstraint::not enough states given");
 
  double sumA = 0, sumPx = 0, sumPy = 0.;
 
  double a;
  for (unsigned int i = 0; i < nPart; ++i) {
    a = -states[i].particleCharge() * states[i].magneticField()->inInverseGeV(states[i].globalPosition()).z();
    sumA += a;
 
    sumPx += states[i].kinematicParameters()(3) - a * (point.y() - states[i].kinematicParameters()(1));
    sumPy += states[i].kinematicParameters()(4) + a * (point.x() - states[i].kinematicParameters()(0));
  }
 
  //xv component
  res(1, 1) = -2 * sumPy * sumA;
 
  //yv component
  res(1, 2) = 2 * sumPx * sumA;
 
  //zv component
  res(1, 3) = 0.;
 
  return res;
}

References a, mps_fire::i, nPart, and point.

value()

AlgebraicVector MultiTrackMassKinematicConstraint::value ( const std::vector< KinematicState > &  states, const GlobalPoint &  point  ) const

overridevirtual

Returns a vector of values of constraint equations at the point where the input particles are defined.

Implements MultiTrackKinematicConstraint.

Definition at line 4 of file MultiTrackMassKinematicConstraint.cc.

                                                                                         {
  if (states.size() < nPart)
    throw VertexException("MultiTrackMassKinematicConstraint::not enough states given");
 
  double sumEnergy = 0, sumPx = 0, sumPy = 0., sumPz = 0.;
 
  double a;
  for (unsigned int i = 0; i < nPart; ++i) {
    a = -states[i].particleCharge() * states[i].magneticField()->inInverseGeV(states[i].globalPosition()).z();
 
    sumEnergy += states[i].kinematicParameters().energy();
    sumPx += states[i].kinematicParameters()(3) - a * (point.y() - states[i].kinematicParameters()(1));
    sumPy += states[i].kinematicParameters()(4) + a * (point.x() - states[i].kinematicParameters()(0));
    sumPz += states[i].kinematicParameters()(5);
  }
 
  double j_m = sumPx * sumPx + sumPy * sumPy + sumPz * sumPz;
 
  AlgebraicVector res(1, 0);
  res(1) = sumEnergy * sumEnergy - j_m - mass * mass;
  return res;
}

References a, mps_fire::i, mass, nPart, and point.

Member Data Documentation

mass

const ParticleMass MultiTrackMassKinematicConstraint::mass

private

Definition at line 55 of file MultiTrackMassKinematicConstraint.h.

Referenced by Particle.Particle::__str__(), ZMuMuRochCorAnalyzer.DiMuon::__str__(), DiObject.DiMuon::__str__(), and value().

nPart

const unsigned int MultiTrackMassKinematicConstraint::nPart

private

Definition at line 56 of file MultiTrackMassKinematicConstraint.h.

Referenced by parametersDerivative(), positionDerivative(), and value().