Abstract base class for particle decay processes. More...

#include <Decay.h>

Inheritance diagram for Decay:

Collaboration diagram for Decay:

Classes
struct	DecayedParentViews

Public Member Functions
	Decay (double restLifetimeSeconds, std::size_t containerIndex, double parentMassGeV, int parentChargeSign)

	~Decay () override=default

void	setDaughterContainer (std::shared_ptr< ParticleContainer< double, 3 > > daughterPC, double daughterMassGeV)
	Set the daughter particle container and its rest mass.

size_t	apply (ParticleContainer< double, 3 > &pc, double dt, long long globalTrackStep, size_t containerIdx) override

virtual void	createDaughterParticles (std::size_t localDestroyNum, std::size_t oldDaughterLocal, const Kokkos::View< ippl::Vector< double, 3 > * > &parentR, const Kokkos::View< ippl::Vector< double, 3 > * > &parentP, const Kokkos::View< double * > &parentDt, const Kokkos::View< ippl::Vector< float, 3 > * > &parentPol)=0
	Create daughter particles from collected parent data.

ippl::detail::size_type	markDecayedParticles (ippl::detail::size_type nLocal, double dt, Kokkos::View< ippl::Vector< double, 3 > * > Pview, Kokkos::View< bool * > decayed)
	Mark particles for decay using the relativistic exponential law.

DecayedParentViews	collectDecayedParents (ippl::detail::size_type nLocal, ippl::detail::size_type localDestroyNum, Kokkos::View< bool * > decayed, Kokkos::View< ippl::Vector< double, 3 > * > Rview, Kokkos::View< ippl::Vector< double, 3 > * > Pview, Kokkos::View< double * > dtView, Kokkos::View< ippl::Vector< float, 3 > * > PolView)
	Gather R/P/dt of parents marked for decay into compact views.

Protected Attributes
double	tau0_m
	Mean lifetime at rest [s].

Kokkos::Random_XorShift64_Pool	randPool_m
	Random pool for decay sampling.

std::shared_ptr< ParticleContainer< double, 3 > >	daughterPC_m
	Daughter container for decay products (nullptr = destroy-only mode).

short	allowedDaughterSpecies_m = -1

double	daughterMassGeV_m = 0.0
	Rest mass of the daughter particle [GeV].

double	parentMassGeV_m
	Rest mass of the parent particle [GeV].

int	parentChargeSign_m

Detailed Description

Abstract base class for particle decay processes.

Note

Handles the shared mechanics of relativistic decay:

Mark particles as decayed (exponential law with time dilation)
Collect parent kinematics into compact temporary views
Delegate daughter creation to the subclass via createDaughterParticles()
Leave parent deletion to ParticleContainer::deleteInvalidParticles()

Subclasses implement the physics-specific daughter momentum sampling (e.g. Michel spectrum for muon decay, fixed two-body kinematics for pion decay). If no daughter container is set, decayed particles are simply marked for deletion.

Definition at line 28 of file Decay.h.

Class Documentation

◆ Decay::DecayedParentViews

struct Decay::DecayedParentViews

Compact views of the kinematics of parents marked for decay. Pol is length-0 when the parent container does not track spin.

Definition at line 67 of file Decay.h.

Collaboration diagram for Decay::DecayedParentViews:

Class Members
View< double * >	dt
View< Vector< double, 3 > * >	P
View< Vector< float, 3 > * >	Pol
View< Vector< double, 3 > * >	R

Constructor & Destructor Documentation

◆ Decay()

Decay::Decay	(	double	restLifetimeSeconds,
		std::size_t	containerIndex,
		double	parentMassGeV,
		int	parentChargeSign
	)

Definition at line 25 of file Decay.cpp.

◆ ~Decay()

Decay::~Decay ( )

overridedefault

Member Function Documentation

◆ apply()

size_t Decay::apply	(	ParticleContainer< double, 3 > &	pc,
		double	dt,
		long long	globalTrackStep,
		size_t	containerIdx
	)

overridevirtual

Implements GlobalProcess.

Definition at line 33 of file Decay.cpp.

References collectDecayedParents(), createDaughterParticles(), daughterPC_m, ParticleContainer< T, Dim >::dt, Decay::DecayedParentViews::dt, ParticleContainer< T, Dim >::hasSpin(), ParticleContainer< T, Dim >::InvalidMask, markDecayedParticles(), ParticleContainer< T, Dim >::P, Decay::DecayedParentViews::P, ParticleContainer< T, Dim >::Pol, Decay::DecayedParentViews::Pol, Decay::DecayedParentViews::R, and tau0_m.

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◆ collectDecayedParents()

Decay::DecayedParentViews Decay::collectDecayedParents	(	ippl::detail::size_type	nLocal,
		ippl::detail::size_type	localDestroyNum,
		Kokkos::View< bool * >	decayed,
		Kokkos::View< ippl::Vector< double, 3 > * >	Rview,
		Kokkos::View< ippl::Vector< double, 3 > * >	Pview,
		Kokkos::View< double * >	dtView,
		Kokkos::View< ippl::Vector< float, 3 > * >	PolView
	)

Gather R/P/dt of parents marked for decay into compact views.

Note: Uses no class state, so no capture shields are needed; still a member for organizational grouping with markDecayedParticles.

Definition at line 115 of file Decay.cpp.

Referenced by apply().

◆ createDaughterParticles()

virtual void Decay::createDaughterParticles	(	std::size_t	localDestroyNum,
		std::size_t	oldDaughterLocal,
		const Kokkos::View< ippl::Vector< double, 3 > * > &	parentR,
		const Kokkos::View< ippl::Vector< double, 3 > * > &	parentP,
		const Kokkos::View< double * > &	parentDt,
		const Kokkos::View< ippl::Vector< float, 3 > * > &	parentPol
	)

pure virtual

Create daughter particles from collected parent data.

Note: Called only when daughterPC_m is set and localDestroyNum > 0. Subclasses implement the physics-specific momentum sampling here. Must be public because device compilers require that a Kokkos lambda's enclosing member function has public access.

Implemented in MuonDecay, and PionDecay.

Referenced by apply().

◆ markDecayedParticles()

ippl::detail::size_type Decay::markDecayedParticles	(	ippl::detail::size_type	nLocal,
		double	dt,
		Kokkos::View< ippl::Vector< double, 3 > * >	Pview,
		Kokkos::View< bool * >	decayed
	)

Mark particles for decay using the relativistic exponential law.

Note: tau0_m and randPool_m are copied into locals before the device kernel so the KOKKOS_LAMBDA captures values — never this.

Definition at line 86 of file Decay.cpp.

References randPool_m, and tau0_m.

Referenced by apply().

◆ setDaughterContainer()

void Decay::setDaughterContainer	(	std::shared_ptr< ParticleContainer< double, 3 > >	daughterPC,
		double	daughterMassGeV
	)

Set the daughter particle container and its rest mass.

Parameters

daughterPC	Container that receives decay products.
daughterMassGeV	Rest mass of the daughter particle [GeV].

Note: When set, decayed particles spawn a daughter in daughterPC. When not set (default), decayed particles are marked for deletion.

Definition at line 161 of file Decay.cpp.

References allowedDaughterSpecies_m, daughterMassGeV_m, daughterPC_m, and ParticleProperties::getParticleTypeString().

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Member Data Documentation

◆ allowedDaughterSpecies_m

short Decay::allowedDaughterSpecies_m = -1

protected

Physically allowed daughter species (short value of ParticleType enum). Subclasses should set this in their constructor; default = ParticleType::UNNAMED (-1).

Definition at line 108 of file Decay.h.

Referenced by MuonDecay::MuonDecay(), PionDecay::PionDecay(), and setDaughterContainer().

◆ daughterMassGeV_m

double Decay::daughterMassGeV_m = 0.0

protected

Rest mass of the daughter particle [GeV].

Definition at line 111 of file Decay.h.

Referenced by MuonDecay::createDaughterParticles(), PionDecay::createDaughterParticles(), and setDaughterContainer().

◆ daughterPC_m

std::shared_ptr<ParticleContainer<double, 3> > Decay::daughterPC_m

protected

Daughter container for decay products (nullptr = destroy-only mode).

Definition at line 104 of file Decay.h.

Referenced by apply(), MuonDecay::createDaughterParticles(), PionDecay::createDaughterParticles(), and setDaughterContainer().

◆ parentChargeSign_m

int Decay::parentChargeSign_m

protected

Sign of parent particle. Either +1, 0, -1. Necessary because the Muon decay is charge dependent.

Definition at line 118 of file Decay.h.

Referenced by MuonDecay::createDaughterParticles(), and PionDecay::createDaughterParticles().

◆ parentMassGeV_m

double Decay::parentMassGeV_m

protected

Rest mass of the parent particle [GeV].

Definition at line 114 of file Decay.h.

Referenced by MuonDecay::createDaughterParticles(), and PionDecay::createDaughterParticles().

◆ randPool_m

Kokkos::Random_XorShift64_Pool Decay::randPool_m

protected

Random pool for decay sampling.

Definition at line 101 of file Decay.h.

Referenced by MuonDecay::createDaughterParticles(), PionDecay::createDaughterParticles(), and markDecayedParticles().

◆ tau0_m

double Decay::tau0_m

protected

Mean lifetime at rest [s].

Definition at line 98 of file Decay.h.

Referenced by apply(), and markDecayedParticles().

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

Classes

Public Member Functions

Protected Attributes

Detailed Description

Class Documentation

◆ Decay::DecayedParentViews

Constructor & Destructor Documentation

◆ Decay()

◆ ~Decay()

Member Function Documentation

◆ apply()

◆ collectDecayedParents()

◆ createDaughterParticles()

◆ markDecayedParticles()

◆ setDaughterContainer()

Member Data Documentation

◆ allowedDaughterSpecies_m

◆ daughterMassGeV_m

◆ daughterPC_m

◆ parentChargeSign_m

◆ parentMassGeV_m

◆ randPool_m

◆ tau0_m