Class to describe the kinematics of an object that can have negative energies. More...

#include <SignedKinematics.h>

Collaboration diagram for HLT::MET::SignedKinematics:

Public Member Functions
	SignedKinematics ()
	SignedKinematics (double px, double py, double pz, double energy)
	Constructor from px, py, pz and E.
	SignedKinematics (const TLorentzVector &tlv)
	Construct from a TLorentzVector.
	SignedKinematics (const xAOD::IParticle &particle)
	Construct from an IParticle.
int	sign () const
	The sign of the kinematics.
double	eta () const
	Direction.
double	phi () const
double	sinPhi () const
	Provide accessors for sin and cos phi.
double	cosPhi () const
double	sinhEta () const
	Provide accessors for sinh and cosh eta.
double	coshEta () const
double	p () const
	Momentum values (signed) momentum.
double	absP () const
	unsigned momentum
double	p2 () const
double	pt () const
	(signed) pt
double	absPt () const
	unsigned pt
double	pt2 () const
double	px () const
double	py () const
double	pz () const
double	energy () const
	Energy values (signed) energy.
double	absEnergy () const
	unsigned energy
double	energy2 () const
double	et () const
	(signed) et
double	absEt () const
	Unsigned et.
double	et2 () const
double	ex () const
double	ey () const
double	ez () const
double	m2 () const
	The squared mass. There is no guarantee that this will be > 0.
	operator ROOT::Math::PxPyPzEVector () const
SignedKinematics &	operator+= (const SignedKinematics &other)
	Add another SignedKinematics to this.
SignedKinematics &	operator-= (const SignedKinematics &other)
	Subtract a SignedKinematics from this (exact opposite of the above function.

Static Public Member Functions
static SignedKinematics	fromEnergyEtaPhi (double energy, double eta, double phi)
	Factory function to construct from energy, eta, phi (massless)
static SignedKinematics	fromEnergyEtaPhiM (double energy, double eta, double phi, double mass)
	Factory function to construct from energy eta, phi and m.
static SignedKinematics	fromEtEtaPhi (double et, double eta, double phi)
	Factory function to construct from et, eta, phi (massless)
static SignedKinematics	fromEtEtaPhiM (double et, double eta, double phi, double mass)
	Factory function to construct from et eta, phi and m.

Private Attributes
ROOT::Math::PxPyPzEVector	m_p4
	The actual kinematics.

Detailed Description

Class to describe the kinematics of an object that can have negative energies.

This class is used instead of TLorentzVector anywhere that there could be a negative energy. This is to get complete control of the behaviour in that case as TLorentzVector behaves oddly.

Algebraic operators are provided but it's worth noting that negative-energy objects behaviour a little oddly (they are not valid four-momenta after all). This should only really affect the mass.

The sign of the vector is defined as sign(E) where E is the scalar sum of all constituents energies

Definition at line 42 of file SignedKinematics.h.

Constructor & Destructor Documentation

◆ SignedKinematics() [1/4]

HLT::MET::SignedKinematics::SignedKinematics ( )

Definition at line 11 of file SignedKinematics.cxx.

11{}

◆ SignedKinematics() [2/4]

HLT::MET::SignedKinematics::SignedKinematics	(	double	px,
		double	py,
		double	pz,
		double	energy )

Constructor from px, py, pz and E.

Definition at line 12 of file SignedKinematics.cxx.

                                                      :
    m_p4(px, py, pz, energy)
  {}

◆ SignedKinematics() [3/4]

HLT::MET::SignedKinematics::SignedKinematics ( const TLorentzVector & tlv )

Construct from a TLorentzVector.

Definition at line 17 of file SignedKinematics.cxx.

                                                              :
    m_p4(tlv.Px(), tlv.Py(), tlv.Pz(), tlv.E() )
  {}

◆ SignedKinematics() [4/4]

HLT::MET::SignedKinematics::SignedKinematics ( const xAOD::IParticle & particle )

Construct from an IParticle.

Definition at line 21 of file SignedKinematics.cxx.

                                                                  :
    SignedKinematics(fromEnergyEtaPhiM(
          particle.e(), particle.eta(), particle.phi(), particle.m() ) )
  {}

Member Function Documentation

◆ absEnergy()

double HLT::MET::SignedKinematics::absEnergy ( ) const

unsigned energy

Definition at line 134 of file SignedKinematics.cxx.

                                           {
    return abs(energy() );
  }

◆ absEt()

double HLT::MET::SignedKinematics::absEt ( ) const

Unsigned et.

Definition at line 143 of file SignedKinematics.cxx.

                                       {
    return abs(et() );
  }

◆ absP()

double HLT::MET::SignedKinematics::absP ( ) const

unsigned momentum

Definition at line 106 of file SignedKinematics.cxx.

                                      {
    return sqrt(p2() );
  }

◆ absPt()

double HLT::MET::SignedKinematics::absPt ( ) const

unsigned pt

Definition at line 115 of file SignedKinematics.cxx.

                                       {
    return sqrt(pt2() );
  }

◆ coshEta()

double HLT::MET::SignedKinematics::coshEta ( ) const

Definition at line 92 of file SignedKinematics.cxx.

                                         {
    double thePt2 = pt2();
    // if pt is 0 then the value is not determined.
    // Take eta = 0
    if (thePt2 == 0)
      return 1;
    // Otherwise, calculate sinh^2 eta, then use 
    // cosh eta = sqrt(1 + sinh^2 eta)
    return sqrt(1 + pz()*pz() / thePt2);
  }

◆ cosPhi()

double HLT::MET::SignedKinematics::cosPhi ( ) const

Definition at line 79 of file SignedKinematics.cxx.

                                        {
    double thePt = pt();
    // if pt() is 0 then the value is not determined.
    // Take phi = 0
    return (thePt == 0 ? 1 : px() / thePt );
  }

◆ energy()

double HLT::MET::SignedKinematics::energy ( ) const

Energy values (signed) energy.

Definition at line 131 of file SignedKinematics.cxx.

                                        {
    return m_p4.E();
  }

◆ energy2()

double HLT::MET::SignedKinematics::energy2 ( ) const

Definition at line 137 of file SignedKinematics.cxx.

                                         {
    return energy()*energy();
  }

◆ et()

double HLT::MET::SignedKinematics::et ( ) const

(signed) et

Definition at line 140 of file SignedKinematics.cxx.

                                    {
    return energy() / coshEta();
  }

◆ et2()

double HLT::MET::SignedKinematics::et2 ( ) const

Definition at line 146 of file SignedKinematics.cxx.

                                     {
    return et()*et();
  }

◆ eta()

double HLT::MET::SignedKinematics::eta ( ) const

Direction.

Definition at line 62 of file SignedKinematics.cxx.

                                     {
    return sign() * m_p4.Eta();
  }

◆ ex()

double HLT::MET::SignedKinematics::ex ( ) const

Definition at line 149 of file SignedKinematics.cxx.

                                    {
    return et() * cosPhi();
  }

◆ ey()

double HLT::MET::SignedKinematics::ey ( ) const

Definition at line 152 of file SignedKinematics.cxx.

                                    {
    return et() * sinPhi();
  }

◆ ez()

double HLT::MET::SignedKinematics::ez ( ) const

Definition at line 155 of file SignedKinematics.cxx.

                                    {
    return et() * sinhEta();
  }

◆ fromEnergyEtaPhi()

SignedKinematics HLT::MET::SignedKinematics::fromEnergyEtaPhi	(	double	energy,
		double	eta,
		double	phi )

static

Factory function to construct from energy, eta, phi (massless)

Definition at line 26 of file SignedKinematics.cxx.

  {
    return fromEnergyEtaPhiM(energy, eta, phi, 0.);
  }

◆ fromEnergyEtaPhiM()

SignedKinematics HLT::MET::SignedKinematics::fromEnergyEtaPhiM	(	double	energy,
		double	eta,
		double	phi,
		double	mass )

static

Factory function to construct from energy eta, phi and m.

Definition at line 32 of file SignedKinematics.cxx.

  {
    double p = energy;
    if (mass != 0) {
      int sgn = (p > 0) - (p < 0);
      p = sgn * sqrt(p*p - mass*mass);
    }
    double pt = p/std::cosh(eta);
    double pz = pt*std::sinh(eta);
    return SignedKinematics(
        pt*std::cos(phi), pt*std::sin(phi), pz, energy);
  }

◆ fromEtEtaPhi()

SignedKinematics HLT::MET::SignedKinematics::fromEtEtaPhi	(	double	et,
		double	eta,
		double	phi )

static

Factory function to construct from et, eta, phi (massless)

Definition at line 46 of file SignedKinematics.cxx.

  {
    return fromEtEtaPhiM(et, eta, phi, 0.);
  }

◆ fromEtEtaPhiM()

SignedKinematics HLT::MET::SignedKinematics::fromEtEtaPhiM	(	double	et,
		double	eta,
		double	phi,
		double	mass )

static

Factory function to construct from et eta, phi and m.

Definition at line 52 of file SignedKinematics.cxx.

  {
    return fromEnergyEtaPhiM(et*std::cosh(eta), eta, phi, mass);
  }

◆ m2()

double HLT::MET::SignedKinematics::m2 ( ) const

The squared mass. There is no guarantee that this will be > 0.

Definition at line 159 of file SignedKinematics.cxx.

                                    {
    return energy2() - p2();
  }

◆ operator ROOT::Math::PxPyPzEVector()

HLT::MET::SignedKinematics::operator ROOT::Math::PxPyPzEVector ( ) const

explicit

Definition at line 163 of file SignedKinematics.cxx.

                                                         {
    return m_p4;
  }

◆ operator+=()

SignedKinematics & HLT::MET::SignedKinematics::operator+= ( const SignedKinematics & other )

Add another SignedKinematics to this.

Definition at line 167 of file SignedKinematics.cxx.

  {
    m_p4.SetPx(px()+other.px() );
    m_p4.SetPy(py()+other.py() );
    m_p4.SetPz(pz()+other.pz() );
    m_p4.SetE(energy()+other.energy() );
    return *this;
  }

◆ operator-=()

SignedKinematics & HLT::MET::SignedKinematics::operator-= ( const SignedKinematics & other )

Subtract a SignedKinematics from this (exact opposite of the above function.

Definition at line 175 of file SignedKinematics.cxx.

  {
    m_p4.SetPx(px()-other.px() );
    m_p4.SetPy(py()-other.py() );
    m_p4.SetPz(pz()-other.pz() );
    m_p4.SetE(energy()-other.energy() );
    return *this;
  }

◆ p()

double HLT::MET::SignedKinematics::p ( ) const

Momentum values (signed) momentum.

Definition at line 103 of file SignedKinematics.cxx.

                                   {
    return sign() * absP();
  }

◆ p2()

double HLT::MET::SignedKinematics::p2 ( ) const

Definition at line 109 of file SignedKinematics.cxx.

                                    {
    return pt2() + pz()*pz();
  }

◆ phi()

double HLT::MET::SignedKinematics::phi ( ) const

Definition at line 66 of file SignedKinematics.cxx.

                                     {
    double val = m_p4.Phi();
    if (sign() < 0)
      val += TMath::Pi();
    return TVector2::Phi_0_2pi(val);
  }

◆ pt()

double HLT::MET::SignedKinematics::pt ( ) const

(signed) pt

Definition at line 112 of file SignedKinematics.cxx.

                                    {
    return sign() * absPt();
  }

◆ pt2()

double HLT::MET::SignedKinematics::pt2 ( ) const

Definition at line 118 of file SignedKinematics.cxx.

                                     {
    return px()*px() + py()*py();
  }

◆ px()

double HLT::MET::SignedKinematics::px ( ) const

Definition at line 121 of file SignedKinematics.cxx.

                                    {
    return m_p4.Px();
  }

◆ py()

double HLT::MET::SignedKinematics::py ( ) const

Definition at line 124 of file SignedKinematics.cxx.

                                    {
    return m_p4.Py();
  }

◆ pz()

double HLT::MET::SignedKinematics::pz ( ) const

Definition at line 127 of file SignedKinematics.cxx.

                                    {
    return m_p4.Pz();
  }

◆ sign()

int HLT::MET::SignedKinematics::sign ( ) const

The sign of the kinematics.

Definition at line 58 of file SignedKinematics.cxx.

                                   {
    return (energy() > 0) - (energy() < 0);
  }

◆ sinhEta()

double HLT::MET::SignedKinematics::sinhEta ( ) const

Provide accessors for sinh and cosh eta.

Definition at line 86 of file SignedKinematics.cxx.

                                         {
    double thePt = pt();
    // if pt is 0 then the value is not determined.
    // Take eta = 0
    return (thePt == 0 ? 0 : pz() / thePt );
  }

◆ sinPhi()

double HLT::MET::SignedKinematics::sinPhi ( ) const

Provide accessors for sin and cos phi.

Definition at line 73 of file SignedKinematics.cxx.

                                        {
    double thePt = pt();
    // if pt() is 0 then the value is not determined.
    // For this phi = 0
    return (thePt == 0 ? 0 : py() / thePt );
  }

Member Data Documentation

◆ m_p4

ROOT::Math::PxPyPzEVector HLT::MET::SignedKinematics::m_p4

private

The actual kinematics.

Definition at line 119 of file SignedKinematics.h.

The documentation for this class was generated from the following files:

Public Member Functions

Static Public Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ SignedKinematics() [1/4]

◆ SignedKinematics() [2/4]

◆ SignedKinematics() [3/4]

◆ SignedKinematics() [4/4]

Member Function Documentation

◆ absEnergy()

◆ absEt()

◆ absP()

◆ absPt()

◆ coshEta()

◆ cosPhi()

◆ energy()

◆ energy2()

◆ et()

◆ et2()

◆ eta()

◆ ex()

◆ ey()

◆ ez()

◆ fromEnergyEtaPhi()

◆ fromEnergyEtaPhiM()

◆ fromEtEtaPhi()

◆ fromEtEtaPhiM()

◆ m2()

◆ operator ROOT::Math::PxPyPzEVector()

◆ operator+=()

◆ operator-=()

◆ p()

◆ p2()

◆ phi()

◆ pt()

◆ pt2()

◆ px()

◆ py()

◆ pz()

◆ sign()

◆ sinhEta()

◆ sinPhi()

Member Data Documentation

◆ m_p4