Momentum Class Reference

Container for a particle's 4-momentum, along with useful methods to ease the development of any matrix element level generator. More...

#include <include/CepGen/Physics/Momentum.h>

Inheritance diagram for Momentum:

Collaboration diagram for Momentum:

Public Types
enum	coord_t { X = 0 , Y = 1 , Z = 2 , E = 3 }

Public Member Functions
	Momentum (double x=0., double y=0., double z=0., double t=-1.)
	Build a 4-momentum using its 3-momentum coordinates and its energy.
	Momentum (double *p)
	Build a 4-momentum using its 3-momentum coordinates and its energy.
	Momentum (const Vector &)
	Build a 4-momentum using its 3-momentum coordinates and its energy.
bool	operator== (const Momentum &) const
	Equality operator.
bool	operator!= (const Momentum &oth) const
	Inequality operator.
double	threeProduct (const Momentum &) const
	Scalar product of the 3-momentum with another 3-momentum.
double	fourProduct (const Momentum &) const
	Scalar product of the 4-momentum with another 4-momentum.
double	crossProduct (const Momentum &, coord_t) const
	Vector product of the 3-momentum with another 3-momentum.
Momentum	operator+ () const
	Unary trivial operator.
Momentum	operator- () const
	Unary inverse operator.
Momentum	operator* (double) const
	Multiply all components of a 4-momentum by a scalar.
Momentum &	operator*= (double)
	Multiply all 4-momentum coordinates by a scalar.
Momentum	operator/ (double) const
	Divide all components of a 4-momentum by a scalar.
Momentum &	operator/= (double)
	Divide all 4-momentum coordinates by a scalar.
Momentum	operator+ (const Momentum &) const
	Compute the 4-vector sum of two 4-momenta.
Momentum &	operator+= (const Momentum &)
	Add a 4-momentum through a 4-vector sum.
Momentum	operator- (const Momentum &) const
	Compute the inverse per-coordinate 4-vector.
Momentum &	operator-= (const Momentum &)
	Subtract a 4-momentum through a 4-vector sum.
double	operator* (const Momentum &) const
	Scalar product of two 3-momenta.
Momentum	operator% (const Momentum &) const
	Vector product of two 3-momenta.
double	operator*= (const Momentum &)
	Scalar product of the 3-momentum with another 3-momentum.
	operator Vector () const
	Cast the 4-momentum object into a 4-dimensional vector.
Momentum &	setP (double px, double py, double pz, double e)
	Set all the components of the 4-momentum (in GeV)
Momentum &	setP (double px, double py, double pz)
	Set all the components of the 3-momentum (in GeV)
Momentum &	setPx (double px)
	Set the momentum along the \(x\)-axis (in GeV)
Momentum &	setPy (double py)
	Set the momentum along the \(y\)-axis (in GeV)
Momentum &	setPz (double pz)
	Set the longitudinal momentum (in GeV)
double	px () const
	Momentum along the \(x\)-axis (in GeV)
double	py () const
	Momentum along the \(y\)-axis (in GeV)
double	pz () const
	Longitudinal momentum (in GeV)
double	pt () const
	Transverse momentum (in GeV)
double	pt2 () const
	Squared transverse momentum (in GeV \(^2\))
std::array< double, 5 >	pVector () const
	5-vector of double precision floats (in GeV)
double	p () const
	3-momentum norm (in GeV)
double	p2 () const
	Squared 3-momentum norm (in GeV \(^2\))
Momentum &	setEnergy (double)
	Set the energy (in GeV)
double	energy () const
	Energy (in GeV)
double	energy2 () const
	Squared energy (in GeV \(^2\))
double	energyT () const
	Transverse energy component (in GeV)
double	energyT2 () const
	Squared transverse energy component (in GeV \(^2\))
Momentum &	setMass2 (double)
	Compute the energy from the mass.
double	mass2 () const
	Squared mass (in GeV \(^2\)) as computed from its energy and momentum.
Momentum &	setMass (double)
	Compute the energy from the mass Mass (in GeV) as computed from its energy and momentum.
double	mass () const
double	massT2 () const
	Squared transverse mass (in GeV \(^2\))
double	massT () const
	Transverse mass (in GeV)
double	theta () const
	Polar angle (angle with respect to the longitudinal direction)
double	phi () const
	Azimuthal angle (angle in the transverse plane)
double	eta () const
	Pseudo-rapidity.
double	rapidity () const
	Rapidity.
Momentum	transverse (coord_t=Z) const
	Transverse coordinates of a momentum.
Momentum	longitudinal (coord_t=Z) const
	Longitudinal component of a momentum.
Momentum &	betaGammaBoost (double gamma, double beta_gamma)
	Forward \(\beta-\gamma\) boost.
Momentum &	lorentzBoost (const Momentum &p)
	Forward Lorentz boost.
double	deltaEta (const Momentum &) const
	Pseudo-rapidity distance between two momenta.
double	deltaPhi (const Momentum &) const
	Azimuthal angle opening between two momenta.
double	deltaPt (const Momentum &) const
	Transverse momentum distance between two momenta.
double	deltaR (const Momentum &) const
	Angular distance between two momenta.
double	beta () const
	Beta scalar value.
double	gamma2 () const
	Squared gamma scalar value.
double	gamma () const
	Gamma scalar value.
Momentum &	computeEnergyFromMass (double on_shell_mass)
	Compute the mass from 4-momentum.
Momentum &	computePzFromMass (double on_shell_mass)
	Compute the longitudinal coordinate from energy-mass-transverse momentum constraints.
Momentum &	truncate (double tolerance=1.e-10)
	Apply a threshold to all values with a given tolerance.
Momentum &	rotatePhi (double phi, double sign)
	Rotate transverse components (+ reflect the y coordinate)
Momentum &	rotateThetaPhi (double theta, double phi)
	Rotate the particle's momentum by a polar/azimuthal angle Apply an \( x\rightarrow -x\) transformation.
Momentum &	mirrorX ()
Momentum &	mirrorY ()
	Apply a \( y\rightarrow -y\) transformation.
Momentum &	mirrorZ ()
	Apply a \( z\rightarrow -z\) transformation.

Static Public Member Functions
static Momentum	fromPtEtaPhiE (double pt, double eta, double phi, double e=-1.)
	Build a 3-momentum from its three pseudo-cylindrical coordinates.
static Momentum	fromPtEtaPhiM (double pt, double eta, double phi, double m)
	Build a 3-momentum from its three pseudo-cylindrical coordinates.
static Momentum	fromPThetaPhiE (double p, double theta, double phi, double e=-1.)
	Build a 4-momentum from its scalar momentum, and its polar and azimuthal angles.
static Momentum	fromPxPyPzE (double px, double py, double pz, double e)
	Build a 4-momentum from its four momentum and energy coordinates.
static Momentum	fromPxPyPzM (double px, double py, double pz, double m)
	Build a 4-momentum from its three momentum coordinates and mass.
static Momentum	fromPxPyYM (double px, double py, double rap, double m)
	Build a 4-momentum from its transverse momentum, rapidity and mass.
static Momentum	fromPtYPhiM (double pt, double rap, double phi, double m)
	Build a 4-momentum from its transverse momentum, azimuthal angle, rapidity and mass.
static Momentum	fromPtYPhiE (double pt, double rap, double phi, double e)
	Build a 4-momentum from its transverse momentum, azimuthal angle, rapidity and energy.

Friends
Momentum	operator* (double, const Momentum &)
	Left-multiply all 4-momentum coordinates by a scalar.
std::ostream &	operator<< (std::ostream &, const Momentum &)
	Human-readable printout of a momentum.

Detailed Description

Date

Dec 2015

Author

Laurent Forthomme laure.nosp@m.nt.f.nosp@m.ortho.nosp@m.mme@.nosp@m.cern..nosp@m.ch

Definition at line 30 of file Momentum.h.

Member Enumeration Documentation

coord_t

enum coord_t

Enumerator
X
Y
Z
E

Definition at line 39 of file Momentum.h.

Constructor & Destructor Documentation

Momentum() [1/3]

Momentum ( double x = 0., double y = 0., double z = 0., double t = -1. )

explicit

Momentum() [2/3]

Momentum ( double * p )

explicit

Momentum() [3/3]

Momentum ( const Vector & )

explicit

Member Function Documentation

beta()

double beta

(

)

const

betaGammaBoost()

Momentum & betaGammaBoost	(	double	gamma,
		double	beta_gamma )

computeEnergyFromMass()

Momentum & computeEnergyFromMass

(

double

on_shell_mass

)

Parameters

[in]

on_shell_mass

Specify on-shell mass (in GeV) to constrain energy

computePzFromMass()

Momentum & computePzFromMass

(

double

on_shell_mass

)

Parameters

[in]

on_shell_mass

Specify on-shell mass (in GeV) to constrain longitudinal momentum

crossProduct()

double crossProduct	(	const Momentum &	,
		coord_t	) const

deltaEta()

double deltaEta

(

const Momentum &

)

const

deltaPhi()

double deltaPhi

(

const Momentum &

)

const

deltaPt()

double deltaPt

(

const Momentum &

)

const

deltaR()

double deltaR

(

const Momentum &

)

const

energy()

double energy

(

)

const

Definition at line 107 of file Momentum.h.

energy2()

double energy2

(

)

const

Definition at line 108 of file Momentum.h.

energyT()

double energyT

(

)

const

energyT2()

double energyT2

(

)

const

eta()

double eta

(

)

const

fourProduct()

double fourProduct

(

const Momentum &

)

const

fromPtEtaPhiE()

static Momentum fromPtEtaPhiE ( double pt, double eta, double phi, double e = -1. )

static

fromPtEtaPhiM()

static Momentum fromPtEtaPhiM ( double pt, double eta, double phi, double m )

static

fromPThetaPhiE()

static Momentum fromPThetaPhiE ( double p, double theta, double phi, double e = -1. )

static

fromPtYPhiE()

static Momentum fromPtYPhiE ( double pt, double rap, double phi, double e )

static

fromPtYPhiM()

static Momentum fromPtYPhiM ( double pt, double rap, double phi, double m )

static

fromPxPyPzE()

static Momentum fromPxPyPzE ( double px, double py, double pz, double e )

static

fromPxPyPzM()

static Momentum fromPxPyPzM ( double px, double py, double pz, double m )

static

fromPxPyYM()

static Momentum fromPxPyYM ( double px, double py, double rap, double m )

static

gamma()

double gamma

(

)

const

gamma2()

double gamma2

(

)

const

longitudinal()

Momentum longitudinal

(

coord_t

= Z

)

const

lorentzBoost()

Momentum & lorentzBoost

(

const Momentum &

p

)

mass()

double mass

(

)

const

mass2()

double mass2

(

)

const

massT()

double massT

(

)

const

massT2()

double massT2

(

)

const

mirrorX()

Momentum & mirrorX

(

)

Definition at line 151 of file Momentum.h.

mirrorY()

Momentum & mirrorY

(

)

Definition at line 156 of file Momentum.h.

mirrorZ()

Momentum & mirrorZ

(

)

Definition at line 161 of file Momentum.h.

operator Vector()

operator Vector

(

)

const

operator!=()

bool operator!=

(

const Momentum &

oth

)

const

Definition at line 41 of file Momentum.h.

operator%()

Momentum operator%

(

const Momentum &

)

const

operator*() [1/2]

double operator*

(

const Momentum &

)

const

operator*() [2/2]

Momentum operator*

(

double

)

const

operator*=() [1/2]

double operator*=

(

const Momentum &

)

operator*=() [2/2]

Momentum & operator*=

(

double

)

operator+() [1/2]

Momentum operator+

(

)

const

operator+() [2/2]

Momentum operator+

(

const Momentum &

)

const

operator+=()

Momentum & operator+=

(

const Momentum &

)

operator-() [1/2]

Momentum operator-

(

)

const

operator-() [2/2]

Momentum operator-

(

const Momentum &

)

const

operator-=()

Momentum & operator-=

(

const Momentum &

)

operator/()

Momentum operator/

(

double

)

const

operator/=()

Momentum & operator/=

(

double

)

operator==()

bool operator==

(

const Momentum &

)

const

p()

double p

(

)

const

Definition at line 104 of file Momentum.h.

p2()

double p2

(

)

const

Definition at line 105 of file Momentum.h.

phi()

double phi

(

)

const

pt()

double pt

(

)

const

pt2()

double pt2

(

)

const

pVector()

std::array< double, 5 > pVector

(

)

const

px()

double px

(

)

const

Definition at line 97 of file Momentum.h.

py()

double py

(

)

const

Definition at line 98 of file Momentum.h.

pz()

double pz

(

)

const

Definition at line 99 of file Momentum.h.

rapidity()

double rapidity

(

)

const

rotatePhi()

Momentum & rotatePhi	(	double	phi,
		double	sign )

rotateThetaPhi()

Momentum & rotateThetaPhi	(	double	theta,
		double	phi )

setEnergy()

Momentum & setEnergy

(

double

)

setMass()

Momentum & setMass

(

double

)

Note

Returns \(-\sqrt{|E^2-\mathbf{p}^2|}<0\) if \(\mathbf{p}^2>E^2\)

setMass2()

Momentum & setMass2

(

double

)

setP() [1/2]

Momentum & setP	(	double	px,
		double	py,
		double	pz )

setP() [2/2]

Momentum & setP	(	double	px,
		double	py,
		double	pz,
		double	e )

setPx()

Momentum & setPx

(

double

px

)

setPy()

Momentum & setPy

(

double

py

)

setPz()

Momentum & setPz

(

double

pz

)

theta()

double theta

(

)

const

threeProduct()

double threeProduct

(

const Momentum &

)

const

transverse()

Momentum transverse

(

coord_t

= Z

)

const

truncate()

Momentum & truncate

(

double

tolerance = 1.e-10

)

Friends And Related Symbol Documentation

operator*

Momentum operator* ( double , const Momentum &  )

friend

operator<<

std::ostream & operator<< ( std::ostream & , const Momentum &  )

friend