Acts::ParticleHypothesis Class Reference

Particle hypothesis used in reconstruction. More...

#include <Acts/EventData/ParticleHypothesis.hpp>

Public Member Functions
constexpr	ParticleHypothesis (PdgParticle absPdg, float mass, ChargeHypothesis charge, std::optional< double > momentum=std::nullopt)
	Creates a particle hypothesis using absolute PDG, mass and the charge type.
constexpr	ParticleHypothesis (PdgParticle absPdg, float mass, float absCharge, std::optional< double > momentum=std::nullopt)
	Creates a particle hypothesis using absolute PDG, mass and the charge type.
	ParticleHypothesis (PdgParticle absPdg, std::optional< double > momentum=std::nullopt)
	Creates a particle hypothesis using the absolute PDG.
float	absoluteCharge () const noexcept
	Get the hypothesized absolute charge.
constexpr PdgParticle	absolutePdg () const noexcept
	Get the hypothesized absolute PDG.
constexpr const ChargeHypothesis &	charge () const noexcept
	Get the hypothesized charge.
constexpr float	extractCharge (double qOverP) const noexcept
	Extracts the signed charge from the q over p track parameter using the charge hypothesis.
constexpr double	extractMomentum (double qOverP) const noexcept
	Extracts the particle momentum from the q over p track parameter using the charge hypothesis.
bool	hasMomentumHypothesis () const noexcept
	Check if the particle hypothesis has a hypothesized momentum.
constexpr float	mass () const noexcept
	Get the hypothesized mass.
double	momentumHypothesis () const
	Get the hypothesized momentum.
constexpr double	qOverP (double momentum, float signedQ) const noexcept
	Calculate the q over p track parameter with the given absolute momentum and charge.
std::ostream &	toStream (std::ostream &os) const
	Output stream representation of the particle hypothesis.
ParticleHypothesis	withAlteredAbsoluteCharge (float absoluteCharge) const
	Create a new particle hypothesis with the same absolute PDG and mass but a different charge.
ParticleHypothesis	withAlteredMass (float mass) const
	Create a new particle hypothesis with the same absolute PDG and charge but a different mass.
ParticleHypothesis	withAlteredPdg (PdgParticle absPdg) const
	Create a new particle hypothesis with the same mass and charge but a different absolute PDG.
ParticleHypothesis	withMomentumHypothesis (double momentum) const
	Create a new particle hypothesis with the same absolute PDG and mass but a different momentum hypothesis.
ParticleHypothesis	withMomentumHypothesis (std::optional< double > momentum) const
	Create a new particle hypothesis with the same absolute PDG and mass but a different momentum hypothesis.
ParticleHypothesis	withoutMomentumHypothesis () const
	Create a new particle hypothesis with the same absolute PDG and mass but no momentum hypothesis.

Static Public Member Functions
static ParticleHypothesis	chargedGeantino ()
	Create a charged geantino particle hypothesis with unit charge.
static ParticleHypothesis	chargedGeantino (float absoluteCharge)
	Create a charged geantino particle hypothesis with custom charge.
static ParticleHypothesis	electron ()
	Create an electron particle hypothesis.
static ParticleHypothesis	geantino ()
	Create a neutral geantino particle hypothesis (massless neutral particle).
static ParticleHypothesis	kaon ()
	Create a charged kaon particle hypothesis.
static ParticleHypothesis	muon ()
	Create a muon particle hypothesis.
static ParticleHypothesis	photon ()
	Create a photon particle hypothesis.
static ParticleHypothesis	pion ()
	Create a charged pion particle hypothesis.
static ParticleHypothesis	pion0 ()
	Create a neutral pion particle hypothesis.
static ParticleHypothesis	pionLike (float absoluteCharge)
	Create a pion-like particle hypothesis with custom charge.
static ParticleHypothesis	proton ()
	Create a proton particle hypothesis.

Detailed Description

Particle hypothesis used in reconstruction.

The reconstruction hypothesis consists of absolute PDG code, mass and absolute charge.

Constructor & Destructor Documentation

ParticleHypothesis() [1/3]

Acts::ParticleHypothesis::ParticleHypothesis ( PdgParticle absPdg, float mass, float absCharge, std::optional< double > momentum = std::nullopt )

constexpr

Creates a particle hypothesis using absolute PDG, mass and the charge type.

Parameters

absPdg	the absolute PDG
mass	the particle mass
absCharge	the absolute charge
momentum	the optional particle momentum

ParticleHypothesis() [2/3]

Acts::ParticleHypothesis::ParticleHypothesis ( PdgParticle absPdg, float mass, ChargeHypothesis charge, std::optional< double > momentum = std::nullopt )

constexpr

Creates a particle hypothesis using absolute PDG, mass and the charge type.

Parameters

absPdg	the absolute PDG
mass	the particle mass
charge	the charge type
momentum	the optional particle momentum

ParticleHypothesis() [3/3]

Acts::ParticleHypothesis::ParticleHypothesis ( PdgParticle absPdg, std::optional< double > momentum = std::nullopt )

explicit

Creates a particle hypothesis using the absolute PDG.

The mass and charge is looked up using findMass and findCharge. If the lookup fails an exception is thrown.

Parameters

absPdg	the absolute PDG
momentum	the optional particle momentum

Member Function Documentation

absoluteCharge()

float Acts::ParticleHypothesis::absoluteCharge ( ) const

nodiscardnoexcept

Get the hypothesized absolute charge.

Returns

The absolute charge magnitude

absolutePdg()

PdgParticle Acts::ParticleHypothesis::absolutePdg ( ) const

nodiscardconstexprnoexcept

Get the hypothesized absolute PDG.

Returns

The absolute PDG particle identifier

charge()

const ChargeHypothesis & Acts::ParticleHypothesis::charge ( ) const

nodiscardconstexprnoexcept

Get the hypothesized charge.

Returns

Reference to the charge type object

chargedGeantino() [1/2]

ParticleHypothesis Acts::ParticleHypothesis::chargedGeantino ( )

staticnodiscard

Create a charged geantino particle hypothesis with unit charge.

Returns

Charged geantino particle hypothesis with any charge type

chargedGeantino() [2/2]

ParticleHypothesis Acts::ParticleHypothesis::chargedGeantino ( float absoluteCharge )

staticnodiscard

Create a charged geantino particle hypothesis with custom charge.

Parameters

absoluteCharge

The absolute charge value

Returns

Charged geantino particle hypothesis with any charge type

electron()

ParticleHypothesis Acts::ParticleHypothesis::electron ( )

staticnodiscard

Create an electron particle hypothesis.

Returns

Electron particle hypothesis with any charge type

extractCharge()

float Acts::ParticleHypothesis::extractCharge ( double qOverP ) const

nodiscardconstexprnoexcept

Extracts the signed charge from the q over p track parameter using the charge hypothesis.

Parameters

qOverP

the q over p track parameter.

Returns

The extracted signed charge

extractMomentum()

double Acts::ParticleHypothesis::extractMomentum ( double qOverP ) const

nodiscardconstexprnoexcept

Extracts the particle momentum from the q over p track parameter using the charge hypothesis.

Parameters

qOverP

the q over p track parameter.

Returns

The extracted absolute momentum

geantino()

ParticleHypothesis Acts::ParticleHypothesis::geantino ( )

staticnodiscard

Create a neutral geantino particle hypothesis (massless neutral particle).

Returns

Neutral geantino particle hypothesis with any charge type

hasMomentumHypothesis()

bool Acts::ParticleHypothesis::hasMomentumHypothesis ( ) const

nodiscardnoexcept

Check if the particle hypothesis has a hypothesized momentum.

Returns

True if a momentum hypothesis is present, false otherwise

kaon()

ParticleHypothesis Acts::ParticleHypothesis::kaon ( )

staticnodiscard

Create a charged kaon particle hypothesis.

Returns

Charged kaon particle hypothesis with any charge type

mass()

float Acts::ParticleHypothesis::mass ( ) const

nodiscardconstexprnoexcept

Get the hypothesized mass.

Returns

The particle mass

momentumHypothesis()

double Acts::ParticleHypothesis::momentumHypothesis ( ) const

nodiscard

Get the hypothesized momentum.

Returns

The particle momentum

muon()

ParticleHypothesis Acts::ParticleHypothesis::muon ( )

staticnodiscard

Create a muon particle hypothesis.

Returns

Muon particle hypothesis with any charge type

photon()

ParticleHypothesis Acts::ParticleHypothesis::photon ( )

staticnodiscard

Create a photon particle hypothesis.

Returns

Photon particle hypothesis with any charge type

pion()

ParticleHypothesis Acts::ParticleHypothesis::pion ( )

staticnodiscard

Create a charged pion particle hypothesis.

Returns

Charged pion particle hypothesis with any charge type

pion0()

ParticleHypothesis Acts::ParticleHypothesis::pion0 ( )

staticnodiscard

Create a neutral pion particle hypothesis.

Returns

Neutral pion particle hypothesis with any charge type

pionLike()

ParticleHypothesis Acts::ParticleHypothesis::pionLike ( float absoluteCharge )

staticnodiscard

Create a pion-like particle hypothesis with custom charge.

Parameters

absoluteCharge

The absolute charge value

Returns

Pion-like particle hypothesis with any charge type

proton()

ParticleHypothesis Acts::ParticleHypothesis::proton ( )

staticnodiscard

Create a proton particle hypothesis.

Returns

Proton particle hypothesis with any charge type

qOverP()

double Acts::ParticleHypothesis::qOverP ( double momentum, float signedQ ) const

nodiscardconstexprnoexcept

Calculate the q over p track parameter with the given absolute momentum and charge.

Parameters

momentum	the absolute momentum.
signedQ	the signed charge.

Returns

The calculated charge over momentum ratio

toStream()

std::ostream & Acts::ParticleHypothesis::toStream

(

std::ostream &

os

)

const

Output stream representation of the particle hypothesis.

Parameters

os	Output stream to write to

Returns

Modified output stream for chaining

withAlteredAbsoluteCharge()

ParticleHypothesis Acts::ParticleHypothesis::withAlteredAbsoluteCharge ( float absoluteCharge ) const

nodiscard

Create a new particle hypothesis with the same absolute PDG and mass but a different charge.

Parameters

absoluteCharge

The new absolute charge value

Returns

A new ParticleHypothesis with the updated charge

withAlteredMass()

ParticleHypothesis Acts::ParticleHypothesis::withAlteredMass ( float mass ) const

nodiscard

Create a new particle hypothesis with the same absolute PDG and charge but a different mass.

Parameters

mass	The new mass value

Returns

A new ParticleHypothesis with the updated mass

withAlteredPdg()

ParticleHypothesis Acts::ParticleHypothesis::withAlteredPdg ( PdgParticle absPdg ) const

nodiscard

Create a new particle hypothesis with the same mass and charge but a different absolute PDG.

Parameters

absPdg

The new absolute PDG value

Returns

A new ParticleHypothesis with the updated absolute PDG

withMomentumHypothesis() [1/2]

ParticleHypothesis Acts::ParticleHypothesis::withMomentumHypothesis ( double momentum ) const

nodiscard

Create a new particle hypothesis with the same absolute PDG and mass but a different momentum hypothesis.

Parameters

momentum

The new momentum hypothesis value

Returns

A new ParticleHypothesis with the updated momentum

withMomentumHypothesis() [2/2]

ParticleHypothesis Acts::ParticleHypothesis::withMomentumHypothesis ( std::optional< double > momentum ) const

nodiscard

Create a new particle hypothesis with the same absolute PDG and mass but a different momentum hypothesis.

Parameters

momentum

The new optional momentum hypothesis value

Returns

A new ParticleHypothesis with the updated momentum

withoutMomentumHypothesis()

ParticleHypothesis Acts::ParticleHypothesis::withoutMomentumHypothesis ( ) const

nodiscard

Create a new particle hypothesis with the same absolute PDG and mass but no momentum hypothesis.

Returns

A new ParticleHypothesis with no momentum hypothesis