Specialized version of the FourVector with momentum/energy functionality. More...

#include <Vector4.hh>

Inheritance diagram for Rivet::FourMomentum:

Public Types
using	EVector = RivetEigen::Matrix< double, N, 1 >
	Vector.

Public Member Functions
template<typename V4TYPE , typename std::enable_if< HasXYZT< V4TYPE >::value, int >::type DUMMY = 0>
	FourMomentum (const V4TYPE &other)

	FourMomentum (const Vector< 4 > &other)

	FourMomentum (const double E, const double px, const double py, const double pz)

	operator fastjet::PseudoJet () const
	Cast operator to FastJet PseudoJet.

double	t () const

double	t2 () const

FourVector &	setT (const double t)

double	x () const

double	x2 () const

FourVector &	setX (const double x)

double	y () const

double	y2 () const

FourVector &	setY (const double y)

double	z () const

double	z2 () const

FourVector &	setZ (const double z)

double	invariant () const

bool	isNull () const

double	angle (const FourVector &v) const
	Angle between this vector and another.

double	angle (const Vector3 &v3) const
	Angle between this vector and another (3-vector)

double	polarRadius2 () const
	Mod-square of the projection of the 3-vector on to the \( x-y \) plane This is a more efficient function than `polarRadius`, as it avoids the square root. Use it if you only need the squared value, or e.g. an ordering by magnitude.

double	perp2 () const
	Synonym for polarRadius2.

double	rho2 () const
	Synonym for polarRadius2.

double	polarRadius () const
	Magnitude of projection of 3-vector on to the \( x-y \) plane.

double	perp () const
	Synonym for polarRadius.

double	rho () const
	Synonym for polarRadius.

Vector3	polarVec () const
	Projection of 3-vector on to the \( x-y \) plane.

Vector3	perpVec () const
	Synonym for polarVec.

Vector3	rhoVec () const
	Synonym for polarVec.

double	azimuthalAngle (const PhiMapping mapping=ZERO_2PI) const
	Angle subtended by the 3-vector's projection in x-y and the x-axis.

double	phi (const PhiMapping mapping=ZERO_2PI) const
	Synonym for azimuthalAngle.

double	polarAngle () const
	Angle subtended by the 3-vector and the z-axis.

double	theta () const
	Synonym for polarAngle.

double	pseudorapidity () const
	Pseudorapidity (defined purely by the 3-vector components)

double	eta () const
	Synonym for pseudorapidity.

double	abspseudorapidity () const
	Get the \( \|\eta\| \) directly.

double	abseta () const
	Get the \( \|\eta\| \) directly (alias).

Vector3	vector3 () const
	Get the spatial part of the 4-vector as a 3-vector.

	operator Vector3 () const
	Implicit cast to a 3-vector.

double	contract (const FourVector &v) const
	Contract two 4-vectors, with metric signature (+ - - -).

double	dot (const FourVector &v) const
	Contract two 4-vectors, with metric signature (+ - - -).

double	operator* (const FourVector &v) const
	Contract two 4-vectors, with metric signature (+ - - -).

FourVector &	operator+= (const FourVector &v)
	Add to this 4-vector.

FourVector &	operator-= (const FourVector &v)
	Subtract from this 4-vector. NB time as well as space components are subtracted.

const double &	get (const size_t index) const

double &	get (const size_t index)

const double &	operator[] (const size_t index) const
	Direct access to vector elements by index.

double &	operator[] (const size_t index)
	Direct access to vector elements by index.

Vector< N > &	set (const size_t index, const double value)
	Set indexed value.

constexpr size_t	size () const
	Vector dimensionality.

bool	isZero (double tolerance=1E-5) const
	Check for nullness, allowing for numerical precision.

double	mod2 () const
	Calculate the modulus-squared of a vector. \( \sum_{i=1}^N x_i^2 \).

double	mod () const
	Calculate the modulus of a vector. \( \sqrt{\sum_{i=1}^N x_i^2} \).

bool	operator== (const Vector< N > &a) const

bool	operator!= (const Vector< N > &a) const

Coordinate setters
FourMomentum &	setE (double E)
	Set energy \( E \) (time component of momentum).

FourMomentum &	setPx (double px)
	Set x-component of momentum \( p_x \).

FourMomentum &	setPy (double py)
	Set y-component of momentum \( p_y \).

FourMomentum &	setPz (double pz)
	Set z-component of momentum \( p_z \).

FourMomentum &	setPE (double px, double py, double pz, double E)
	Set the p coordinates and energy simultaneously.

FourMomentum &	setXYZE (double px, double py, double pz, double E)
	Alias for setPE.

FourMomentum &	setPM (double px, double py, double pz, double mass)
	Set the p coordinates and mass simultaneously.

FourMomentum &	setXYZM (double px, double py, double pz, double mass)
	Alias for setPM.

FourMomentum &	setEtaPhiME (double eta, double phi, double mass, double E)

FourMomentum &	setEtaPhiMPt (double eta, double phi, double mass, double pt)

FourMomentum &	setRapPhiME (double y, double phi, double mass, double E)

FourMomentum &	setRapPhiMPt (double y, double phi, double mass, double pt)

FourMomentum &	setThetaPhiME (double theta, double phi, double mass, double E)

FourMomentum &	setThetaPhiMPt (double theta, double phi, double mass, double pt)

FourMomentum &	setPtPhiME (double pt, double phi, double mass, double E)

Accessors
double	E () const
	Get energy \( E \) (time component of momentum).

double	E2 () const
	Get energy-squared \( E^2 \).

double	px () const
	Get x-component of momentum \( p_x \).

double	px2 () const
	Get x-squared \( p_x^2 \).

double	py () const
	Get y-component of momentum \( p_y \).

double	py2 () const
	Get y-squared \( p_y^2 \).

double	pz () const
	Get z-component of momentum \( p_z \).

double	pz2 () const
	Get z-squared \( p_z^2 \).

double	mass () const
	Get the mass \( m = \sqrt{E^2 - p^2} \) (the Lorentz self-invariant).

double	mass2 () const
	Get the squared mass \( m^2 = E^2 - p^2 \) (the Lorentz self-invariant).

Vector3	p3 () const
	Get 3-momentum part, \( p \).

double	p () const
	Get the modulus of the 3-momentum.

double	p2 () const
	Get the modulus-squared of the 3-momentum.

double	rapidity () const
	Calculate the rapidity.

double	rap () const
	Alias for rapidity.

double	absrapidity () const
	Absolute rapidity.

double	absrap () const
	Absolute rapidity.

Vector3	pTvec () const
	Calculate the transverse momentum vector \( \vec{p}_T \).

Vector3	ptvec () const
	Synonym for pTvec.

double	pT2 () const
	Calculate the squared transverse momentum \( p_T^2 \).

double	pt2 () const
	Calculate the squared transverse momentum \( p_T^2 \).

double	pT () const
	Calculate the transverse momentum \( p_T \).

double	pt () const
	Calculate the transverse momentum \( p_T \).

double	Et2 () const
	Calculate the transverse energy \( E_T^2 = E^2 \sin^2{\theta} \).

double	Et () const
	Calculate the transverse energy \( E_T = E \sin{\theta} \).

Lorentz boost factors and vectors
double	gamma () const

Vector3	gammaVec () const

double	beta () const

Vector3	betaVec () const

Arithmetic operators
FourMomentum &	*operator=** (double a)
	Multiply by a scalar.

FourMomentum &	operator/= (double a)
	Divide by a scalar.

FourMomentum &	operator+= (const FourMomentum &v)
	Add to this 4-vector. NB time as well as space components are added.

FourMomentum &	operator-= (const FourMomentum &v)
	Subtract from this 4-vector. NB time as well as space components are subtracted.

FourMomentum	operator- () const
	Multiply all components (time and space) by -1.

FourMomentum	reverse () const
	Multiply space components only by -1.

Static Public Member Functions
Factory functions
static FourMomentum	mkXYZE (double px, double py, double pz, double E)
	Make a vector from (px,py,pz,E) coordinates.

static FourMomentum	mkXYZM (double px, double py, double pz, double mass)
	Make a vector from (px,py,pz) coordinates and the mass.

static FourMomentum	mkEtaPhiME (double eta, double phi, double mass, double E)
	Make a vector from (eta,phi,energy) coordinates and the mass.

static FourMomentum	mkEtaPhiMPt (double eta, double phi, double mass, double pt)
	Make a vector from (eta,phi,pT) coordinates and the mass.

static FourMomentum	mkRapPhiME (double y, double phi, double mass, double E)
	Make a vector from (y,phi,energy) coordinates and the mass.

static FourMomentum	mkRapPhiMPt (double y, double phi, double mass, double pt)
	Make a vector from (y,phi,pT) coordinates and the mass.

static FourMomentum	mkThetaPhiME (double theta, double phi, double mass, double E)
	Make a vector from (theta,phi,energy) coordinates and the mass.

static FourMomentum	mkThetaPhiMPt (double theta, double phi, double mass, double pt)
	Make a vector from (theta,phi,pT) coordinates and the mass.

static FourMomentum	mkPtPhiME (double pt, double phi, double mass, double E)
	Make a vector from (pT,phi,energy) coordinates and the mass.

Friends
FourMomentum	multiply (const double a, const FourMomentum &v)

FourMomentum	multiply (const FourMomentum &v, const double a)

FourMomentum	add (const FourMomentum &a, const FourMomentum &b)

FourMomentum	transform (const LorentzTransform &lt, const FourMomentum &v4)

Detailed Description

Specialized version of the FourVector with momentum/energy functionality.

Member Function Documentation

◆ beta()

double Rivet::FourMomentum::beta ( ) const

inline

Calculate the boost factor \( \beta \).

Note: \( \beta = pc/E \) so we rely on the c=1 convention

References E(), and p().

◆ betaVec()

Vector3 Rivet::FourMomentum::betaVec ( ) const

inline

Calculate the boost vector \( \vec{\beta} \).

Note: \( \beta = pc/E \) so we rely on the c=1 convention

References E(), and p3().

Referenced by Rivet::LorentzTransform::mkFrameTransform(), and Rivet::LorentzTransform::mkObjTransform().

◆ gamma()

double Rivet::FourMomentum::gamma ( ) const

inline

Calculate the boost factor \( \gamma \).

Note: \( \gamma = E/mc^2 \) so we rely on the c=1 convention

References E2(), Rivet::FourVector::eta(), and mass2().

Referenced by gammaVec().

◆ gammaVec()

Vector3 Rivet::FourMomentum::gammaVec ( ) const

inline

Calculate the boost vector \( \vec{\gamma} \).

Note: \( \gamma = E/mc^2 \) so we rely on the c=1 convention

References gamma(), p3(), and Rivet::Vector3::unit().

◆ mass()

double Rivet::FourMomentum::mass ( ) const

inline

Get the mass \( m = \sqrt{E^2 - p^2} \) (the Lorentz self-invariant).

For spacelike momenta, the mass will be -sqrt(|mass2|).

References Rivet::FourVector::eta(), mass2(), and Rivet::sign().

Referenced by Rivet::cmpMomByAscMass(), Rivet::cmpMomByMass(), Rivet::ParticleBase::mass(), mkEtaPhiME(), mkEtaPhiMPt(), mkPtPhiME(), mkRapPhiME(), mkRapPhiMPt(), mkThetaPhiME(), mkThetaPhiMPt(), mkXYZM(), setEtaPhiME(), setEtaPhiMPt(), setPM(), setPtPhiME(), setRapPhiME(), setRapPhiMPt(), setThetaPhiME(), setThetaPhiMPt(), and setXYZM().

◆ operator fastjet::PseudoJet()

Rivet::FourVector::operator fastjet::PseudoJet ( ) const

inherited

Cast operator to FastJet PseudoJet.

Needed, since otherwise the PseudoJet template constructor assumes the indices [0-3] mean px,py,pz,E... but Rivet uses E,px,py,pz ordering.

◆ setEtaPhiME()

FourMomentum & Rivet::FourMomentum::setEtaPhiME	(	double	eta,
		double	phi,
		double	mass,
		double	E
	)

inline

Set the vector state from (eta,phi,energy) coordinates and the mass

eta = -ln(tan(theta/2)) -> theta = 2 atan(exp(-eta))

References E(), Rivet::FourVector::eta(), mass(), Rivet::FourVector::phi(), setThetaPhiME(), and Rivet::FourVector::theta().

Referenced by mkEtaPhiME().

◆ setEtaPhiMPt()

FourMomentum & Rivet::FourMomentum::setEtaPhiMPt	(	double	eta,
		double	phi,
		double	mass,
		double	pt
	)

inline

Set the vector state from (eta,phi,pT) coordinates and the mass

eta = -ln(tan(theta/2)) -> theta = 2 atan(exp(-eta))

References E(), Rivet::FourVector::eta(), mass(), p(), Rivet::FourVector::phi(), pt(), setThetaPhiME(), Rivet::sqr(), and Rivet::FourVector::theta().

Referenced by mkEtaPhiMPt().

◆ setPtPhiME()

FourMomentum & Rivet::FourMomentum::setPtPhiME	(	double	pt,
		double	phi,
		double	mass,
		double	E
	)

inline

Set the vector state from (pT,phi,energy) coordinates and the mass

pz = sqrt(E^2 - mass^2 - pt^2)

References E(), Rivet::FourVector::eta(), mass(), Rivet::FourVector::phi(), pt(), px(), py(), pz(), setPE(), and Rivet::sqr().

Referenced by mkPtPhiME().

◆ setRapPhiME()

FourMomentum & Rivet::FourMomentum::setRapPhiME	(	double	y,
		double	phi,
		double	mass,
		double	E
	)

inline

Set the vector state from (y,phi,energy) coordinates and the mass

y = 0.5 * ln((E+pz)/(E-pz)) -> (E^2 - pz^2) exp(2y) = (E+pz)^2 & (E^2 - pz^2) exp(-2y) = (E-pz)^2 -> E = sqrt(pt^2 + m^2) cosh(y) -> pz = sqrt(pt^2 + m^2) sinh(y) -> sqrt(pt^2 + m^2) = E / cosh(y)

References E(), Rivet::FourVector::eta(), mass(), Rivet::FourVector::phi(), pt(), px(), py(), pz(), setPE(), and Rivet::sqr().

Referenced by mkRapPhiME(), and setRapPhiMPt().