Hammer::FourMomentum Class Reference

4-momentum class More...

#include <FourMomentum.hh>

Inheritance diagram for Hammer::FourMomentum:

Collaboration diagram for Hammer::FourMomentum:

Public Member Functions
	FourMomentum ()
	default constructor More...
	FourMomentum (const std::array< double, 4 > &other)
	constructor from an array of numbers More...
	FourMomentum (const double E, const double px, const double py, const double pz)
	constructor from specific components More...
FourMomentum &	setE (double E)
	set the 4-momentum energy More...
FourMomentum &	setPx (double px)
	set the 4-momentum momentum x component More...
FourMomentum &	setPy (double py)
	set the 4-momentum momentum y component More...
FourMomentum &	setPz (double pz)
	set the 4-momentum momentum z component More...
double	E () const
	returns the energy More...
double	px () const
	returns the momentum x component More...
double	py () const
	returns the momentum y component More...
double	pz () const
	returns the momentum z component More...
double	mass () const
	returns the invariant mass if the invariant mass squared is negative returns \( - \sqrt{|m^2|} \) More...
double	mass2 () const
	returns the squared invariant mass More...
double	p () const
	returns the absolute value of the 3-momentum More...
double	p2 () const
	returns the squared 3-momentum More...
double	pt () const
	returns the transverse momentum More...
double	rapidity () const
	returns the rapidity (along the z-axis) More...
double	phi () const
	returns the azimuthal angle More...
double	eta () const
	returns the pseudorapidity (along the z-axis) More...
double	theta () const
	returns the polar angle (along the z-axis) More...
std::array< double, 3 >	pVec () const
	returns the spatial 3-vector as an array More...
double	dot (const FourMomentum &v) const
	contracts the 4-momentum with another More...
FourMomentum &	operator*= (double a)
	multiplies the components by a constant More...
FourMomentum &	operator/= (double a)
	divides the components by a constant More...
FourMomentum &	operator+= (const FourMomentum &v)
	adds the another 4-momentum to itself More...
FourMomentum &	operator-= (const FourMomentum &v)
	subtract the 4-momentum by another More...
FourMomentum	operator- () const
	construct a copy of itself with all the signs of the components flipped More...
FourMomentum	PFlip () const
	construct a copy of itself with all the signs of the spatial components flipped More...
double	gamma () const
	returns the \( \gamma = 1/\sqrt{1-\beta^2} \) for the Lorentz transformation to the rest frame More...
double	beta () const
	returns the value of the boost to the rest frame More...
std::array< double, 3 >	boostVector () const
	returns the boost 3-vector More...
FourMomentum &	boostToRestFrameOf (const FourMomentum &v)
	returns a boosted 4-vector More...
FourMomentum &	boostFromRestFrameOf (const FourMomentum &v)
FourMomentum &	boostToRestFrameOf (const std::array< double, 3 > &v)

Static Public Member Functions
static FourMomentum	fromPM (double px, double py, double pz, double mass)
	builder method based on 3-momentum and invariant mass More...
static FourMomentum	fromPtEtaPhiM (double pt, double eta, double phi, double mass)
	builder method based on collider-friendly variables More...
static FourMomentum	fromEtaPhiME (double eta, double phi, double mass, double E)
	builder method based on collider-friendly variables More...

Private Member Functions
void	boostBy (const std::array< double, 3 > &v)

Private Attributes
std::array< double, 4 >	_vec
	the contents of the 4-momentum in the notation \( (E, p_x, p_y, p_z) \). More...

Detailed Description

4-momentum class

Defines a 4-momentum and its basic properties and operations

Definition at line 30 of file FourMomentum.hh.

Constructor & Destructor Documentation

Hammer::FourMomentum::FourMomentum

(

)

default constructor

Definition at line 24 of file FourMomentum.cc.

Hammer::FourMomentum::FourMomentum

(

const std::array< double, 4 > &

other

)

constructor from an array of numbers

Parameters

[in]

other

the array, defined as \( \left(E, p_x, p_y, p_z \right) \)

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

constructor from specific components

Parameters

[in]	E	the energy
[in]	px	the x momentum component
[in]	py	the y momentum component
[in]	pz	the z momentum component

Member Function Documentation

double Hammer::FourMomentum::beta

(

)

const

returns the value of the boost to the rest frame

Returns

the value. Throws if zero energy.

void Hammer::FourMomentum::boostBy ( const std::array< double, 3 > &  v )

private

Parameters

[in]

v

Returns

FourMomentum& Hammer::FourMomentum::boostFromRestFrameOf

(

const FourMomentum &

v

)

Parameters

[in]

v

Returns

FourMomentum& Hammer::FourMomentum::boostToRestFrameOf

(

const FourMomentum &

v

)

returns a boosted 4-vector

Parameters

[in]

v

Returns

the boosted 4-vector.

FourMomentum& Hammer::FourMomentum::boostToRestFrameOf

(

const std::array< double, 3 > &

v

)

Parameters

[in]

v

Returns

std::array<double, 3> Hammer::FourMomentum::boostVector

(

)

const

returns the boost 3-vector

Returns

the vector. Throws if zero energy.

double Hammer::FourMomentum::dot

(

const FourMomentum &

v

)

const

contracts the 4-momentum with another

Parameters

[in]

v

the other 4-momentum

Returns

the dot product

double Hammer::FourMomentum::E

(

)

const

returns the energy

double Hammer::FourMomentum::eta

(

)

const

returns the pseudorapidity (along the z-axis)

static FourMomentum Hammer::FourMomentum::fromEtaPhiME ( double  eta, double  phi, double  mass, double  E  )

static

builder method based on collider-friendly variables

Parameters

[in]	eta	the pseudorapidity
[in]	phi	the azimuthal angle
[in]	mass	the invariant mass
[in]	E	the energy

Returns

the built 4-momentum

static FourMomentum Hammer::FourMomentum::fromPM ( double  px, double  py, double  pz, double  mass  )

static

builder method based on 3-momentum and invariant mass

Parameters

[in]	px	the x momentum component
[in]	py	the y momentum component
[in]	pz	the z momentum component
[in]	mass	the invariant mass

Returns

the built 4-momentum

static FourMomentum Hammer::FourMomentum::fromPtEtaPhiM ( double  pt, double  eta, double  phi, double  mass  )

static

builder method based on collider-friendly variables

Parameters

[in]	pt	the transverse momentum
[in]	eta	the pseudorapidity
[in]	phi	the azimuthal angle
[in]	mass	the invariant mass

Returns

the built 4-momentum

double Hammer::FourMomentum::gamma

(

)

const

returns the \( \gamma = 1/\sqrt{1-\beta^2} \) for the Lorentz transformation to the rest frame

Returns

the value. Throws for massless particles.

double Hammer::FourMomentum::mass

(

)

const

returns the invariant mass if the invariant mass squared is negative returns \( - \sqrt{|m^2|} \)

double Hammer::FourMomentum::mass2

(

)

const

returns the squared invariant mass

FourMomentum& Hammer::FourMomentum::operator*=

(

double

a

)

multiplies the components by a constant

Parameters

[in]

a

the real constant

Returns

a reference to itself

FourMomentum& Hammer::FourMomentum::operator+=

(

const FourMomentum &

v

)

adds the another 4-momentum to itself

Parameters

[in]

v

the other 4-momentum

Returns

a reference to itself

FourMomentum Hammer::FourMomentum::operator-

(

)

const

construct a copy of itself with all the signs of the components flipped

Returns

a new 4-vector with the components flipped

FourMomentum& Hammer::FourMomentum::operator-=

(

const FourMomentum &

v

)

subtract the 4-momentum by another

Parameters

[in]

v

the other 4-momentum

Returns

a reference to itself

FourMomentum& Hammer::FourMomentum::operator/=

(

double

a

)

divides the components by a constant

Parameters

[in]

a

the real constant

Returns

a reference to itself. Throws if division-by-zero.

double Hammer::FourMomentum::p

(

)

const

returns the absolute value of the 3-momentum

double Hammer::FourMomentum::p2

(

)

const

returns the squared 3-momentum

FourMomentum Hammer::FourMomentum::PFlip

(

)

const

construct a copy of itself with all the signs of the spatial components flipped

Returns

a new 4-vector with the spatial components flipped

double Hammer::FourMomentum::phi

(

)

const

returns the azimuthal angle

double Hammer::FourMomentum::pt

(

)

const

returns the transverse momentum

std::array<double, 3> Hammer::FourMomentum::pVec

(

)

const

returns the spatial 3-vector as an array

double Hammer::FourMomentum::px

(

)

const

returns the momentum x component

double Hammer::FourMomentum::py

(

)

const

returns the momentum y component

double Hammer::FourMomentum::pz

(

)

const

returns the momentum z component

double Hammer::FourMomentum::rapidity

(

)

const

returns the rapidity (along the z-axis)

FourMomentum& Hammer::FourMomentum::setE

(

double

E

)

set the 4-momentum energy

Parameters

[in]

E

the new energy

Returns

a reference to itself

FourMomentum& Hammer::FourMomentum::setPx

(

double

px

)

set the 4-momentum momentum x component

Parameters

[in]

px

the new momentum x component

Returns

a reference to itself

FourMomentum& Hammer::FourMomentum::setPy

(

double

py

)

set the 4-momentum momentum y component

Parameters

[in]

py

the new momentum y component

Returns

a reference to itself

FourMomentum& Hammer::FourMomentum::setPz

(

double

pz

)

set the 4-momentum momentum z component

Parameters

[in]

pz

the new momentum z component

Returns

a reference to itself

double Hammer::FourMomentum::theta

(

)

const

returns the polar angle (along the z-axis)

Member Data Documentation

std::array<double, 4> Hammer::FourMomentum::_vec

private

the contents of the 4-momentum in the notation \( (E, p_x, p_y, p_z) \).

Definition at line 222 of file FourMomentum.hh.

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

• FourMomentum.hh
• FourMomentum.cc