The DecayPhaseSpaceMode class is designed to store a group of phase-space channels for use by the DecayIntegrator class to generate the phase-space for a given decay mode. More...

#include <DecayPhaseSpaceMode.h>

Inheritance diagram for Herwig::DecayPhaseSpaceMode:

[legend]

List of all members.

Public Member Functions
tcPDPtr	externalParticles (int ix) const
	Access to the external particles.
unsigned int	numberofParticles () const
	Number of external particles.
unsigned int	numberChannels () const
	Number of channels.
void	addChannel (DecayPhaseSpaceChannelPtr channel)
	Add a new channel.
void	resetIntermediate (int ichan, tcPDPtr part, Energy mass, Energy width)
	Reset the properties of one of the intermediate particles.
void	resetIntermediate (tcPDPtr part, Energy mass, Energy width)
	Reset the properties of one of the intermediate particles.
double	maxWeight () const
	Get the maximum weight for the decay.
void	setMaxWeight (double wgt) const
	Set the maximum weight for the decay.
double	channelWeight (unsigned int ichan) const
	Get the weight for a channel.
void	setWeights (const vector< double > &in) const
	Set the weights for the different channels.
unsigned int	selectedChannel () const
	Access to the selected channel.
bool	testOnShell () const
	test on/off-shell kinematics
Standard constructors and destructors.
	DecayPhaseSpaceMode ()
	Default constructor.
	DecayPhaseSpaceMode (tPDVector in, tcDecayIntegratorPtr intin, bool onShell=false)
	Constructor with a pointer to a `DecayPhaseIntegrator` and a vector of particle data objects for the external particles.
Functions used by the persistent I/O system.
void	persistentOutput (PersistentOStream &os) const
	Function used to write out object persistently.
void	persistentInput (PersistentIStream &is, int version)
	Function used to read in object persistently.
Static Public Member Functions
static void	Init ()
	Standard Init function used to initialize the interfaces.
Protected Member Functions
Set-up, Initialization and Access Members
Energy	initializePhaseSpace (bool init, bool onShell=false)
	Initialise the phase space.
void	setIntegrate (int iter, int points, int ntry)
	Set the integration parameters.
void	setPartialWidth (int in)
	Set the partial width to use for normalization.
Phase-Space Generation Members
double	me2 (const int ichan, const Particle &inpart, const ParticleVector &outpart, DecayIntegrator::MEOption opt) const
	Access to the matrix element from the decayer.
ParticleVector	generate (bool intermediates, bool cc, const Particle &inpart) const
	Generate the decay.
int	selectChannel (const Particle &inpart, ParticleVector &outpart) const
	Select which channel to use to output the particles.
Energy	weight (bool cc, int &ichan, const Particle &in, ParticleVector &particles, bool first, bool onShell=false) const
	Return the weight for a given phase-space point.
Energy	flatPhaseSpace (bool cc, const Particle &inpart, ParticleVector &outpart, bool onShell=false) const
	Return the weight and momenta for a flat phase-space decay.
Energy	channelPhaseSpace (bool cc, int &ichan, const Particle &in, ParticleVector &particles, bool onShell=false) const
	Generate a phase-space point using multichannel phase space.
void	constructVertex (const Particle &in, const ParticleVector &out) const
	Construct the vertex for spin corrections.
vector< Energy >	externalMasses (Energy inmass, double &wgt, bool onShell) const
	Generate the masses of the external particles.
Clone Methods.
virtual IBPtr	clone () const
	Make a simple clone of this object.
virtual IBPtr	fullclone () const
	Make a clone of this object, possibly modifying the cloned object to make it sane.
Standard Interfaced functions.
virtual void	doinit ()
	Initialize this object after the setup phase before saving and EventGenerator to disk.
virtual void	doinitrun ()
	Initialize this object to the begining of the run phase.
Private Member Functions
DecayPhaseSpaceMode &	operator= (const DecayPhaseSpaceMode &)
	Private and non-existent assignment operator.
Private Attributes
tcDecayIntegratorPtr	_integrator
	pointer to the decayer
vector< DecayPhaseSpaceChannelPtr >	_channels
	pointers to the phase-space channels
vector< double >	_channelwgts
	the weights for the different channels
double	_maxweight
	the maximum weight for the decay
int	_niter
	Number of iterations for the initialization.
int	_npoint
	Number of weights for each iteration of the initialization.
int	_ntry
	Number of attempts to generate the decay.
tPDVector	_extpart
	External particles.
int	_partial
	Which of the partial widths of the incoming particle to use.
cGenericWidthGeneratorPtr	_widthgen
	The width generator for the incoming particle.
vector< cGenericMassGeneratorPtr >	_massgen
	The mass generators for the outgoing particles.
bool	_testOnShell
	Whether to check on-shell or off-shell kinematics in doinit, if on-shell off-shell is tested in initrun.
unsigned int	_ichannel
	The selected channel.
Static Private Attributes
static ClassDescription < DecayPhaseSpaceMode >	initDecayPhaseSpaceMode
	Describe a concrete class with persistent data.
Friends
class	DecayIntegrator
	DecayIntegrator is a friend to avoid making many of the phase space generation members public.
class	DecayPhaseSpaceChannel
	DecayPhaseSpaceChannel is a friend to avoid making many of the phase space generation members public.
ostream &	operator<< (ostream &, const DecayPhaseSpaceMode &)
	A friend operator to allow the mode to be outputted for debugging purposes.

Detailed Description

The DecayPhaseSpaceMode class is designed to store a group of phase-space channels for use by the DecayIntegrator class to generate the phase-space for a given decay mode.

Additional phase-space channels can be added using the addChannel member.

In practice the modes are usually constructed together with the a number of DecayPhaseSpaceChannel objects. In classes inheriting from the DecayIntegrator class.

See also:: DecayIntegrator; DecayPhaseSpaceChannel

Author:: Peter Richardson

Definition at line 43 of file DecayPhaseSpaceMode.h.

Constructor & Destructor Documentation

Herwig::DecayPhaseSpaceMode::DecayPhaseSpaceMode	(	tPDVector	in,
		tcDecayIntegratorPtr	intin,
		bool	onShell = `false`
	)		`[inline]`

Constructor with a pointer to a DecayPhaseIntegrator and a vector of particle data objects for the external particles.

This is the constructor which should normally be used in decayers.

Parameters:

in	The particle data objects for the external particles
intin	A pointer to the DecayIntegrator class using this mode.
onShell	Whether or not to perform tests for zero width on-shell particles

Definition at line 80 of file DecayPhaseSpaceMode.h.

Member Function Documentation

void Herwig::DecayPhaseSpaceMode::addChannel ( DecayPhaseSpaceChannelPtr channel ) [inline]

Add a new channel.

Parameters:

channel A pointer to the new DecayPhaseChannel

Definition at line 109 of file DecayPhaseSpaceMode.h.

Energy Herwig::DecayPhaseSpaceMode::channelPhaseSpace	(	bool	cc,
		int &	ichan,
		const Particle &	in,
		ParticleVector &	particles,
		bool	onShell = `false`
	)		const `[protected]`

Generate a phase-space point using multichannel phase space.

Parameters:

cc	Whether we are generating the mode specified or the charge conjugate mode.
ichan	The channel to generate the weight for.
in	The incoming particle.
particles	The outgoing particles.

Returns:: The weight.

double Herwig::DecayPhaseSpaceMode::channelWeight ( unsigned int ichan ) const [inline]

Get the weight for a channel.

This is the weight for the multi-channel approach.

Parameters:

ichan The channel.

Returns:: The weight for the channel.

Definition at line 156 of file DecayPhaseSpaceMode.h.

virtual IBPtr Herwig::DecayPhaseSpaceMode::clone ( ) const [inline, protected, virtual]

Make a simple clone of this object.

Returns:: a pointer to the new object.

Implements ThePEG::InterfacedBase.

Definition at line 350 of file DecayPhaseSpaceMode.h.

void Herwig::DecayPhaseSpaceMode::constructVertex	(	const Particle &	in,
		const ParticleVector &	out
	)		const `[protected]`

Construct the vertex for spin corrections.

Parameters:

in	The incoming particle.
out	The outgoing particles.

virtual void Herwig::DecayPhaseSpaceMode::doinit ( ) [protected, virtual]

Initialize this object after the setup phase before saving and EventGenerator to disk.

Exceptions:

InitException if object could not be initialized properly.

Reimplemented from ThePEG::InterfacedBase.

vector<Energy> Herwig::DecayPhaseSpaceMode::externalMasses	(	Energy	inmass,
		double &	wgt,
		bool	onShell
	)		const `[protected]`

Generate the masses of the external particles.

Parameters:

inmass	The mass of the decaying particle.
wgt	The weight for the masses.

Returns:: The masses.

tcPDPtr Herwig::DecayPhaseSpaceMode::externalParticles ( int ix ) const [inline]

Access to the external particles.

Parameters:

ix	The external particle required.

Returns:: A pointer to the ParticleData object.

Definition at line 91 of file DecayPhaseSpaceMode.h.

Energy Herwig::DecayPhaseSpaceMode::flatPhaseSpace	(	bool	cc,
		const Particle &	inpart,
		ParticleVector &	outpart,
		bool	onShell = `false`
	)		const `[protected]`

Return the weight and momenta for a flat phase-space decay.

Parameters:

cc	Whether we are generating the mode specified or the charge conjugate mode.
inpart	The incoming particle.
outpart	The outgoing particles.

Returns:: The weight.

virtual IBPtr Herwig::DecayPhaseSpaceMode::fullclone ( ) const [inline, protected, virtual]

Make a clone of this object, possibly modifying the cloned object to make it sane.

Returns:: a pointer to the new object.

Reimplemented from ThePEG::InterfacedBase.

Definition at line 356 of file DecayPhaseSpaceMode.h.

ParticleVector Herwig::DecayPhaseSpaceMode::generate	(	bool	intermediates,
		bool	cc,
		const Particle &	inpart
	)		const `[protected]`

Generate the decay.

Parameters:

intermediates	Whether or not to generate the intermediate particle in the decay channel.
cc	Whether we are generating the mode specified or the charge conjugate mode.
inpart	The incoming particle.

Returns:: The outgoing particles.

Energy Herwig::DecayPhaseSpaceMode::initializePhaseSpace	(	bool	init,
		bool	onShell = `false`
	)		`[protected]`

Initialise the phase space.

Parameters:

init	Perform the initialization.

double Herwig::DecayPhaseSpaceMode::maxWeight ( ) const [inline]

Get the maximum weight for the decay.

Returns:: The maximum weight.

Definition at line 143 of file DecayPhaseSpaceMode.h.

double Herwig::DecayPhaseSpaceMode::me2	(	const int	ichan,
		const Particle &	inpart,
		const ParticleVector &	outpart,
		DecayIntegrator::MEOption	opt
	)		const `[inline, protected]`

Access to the matrix element from the decayer.

Parameters:

ichan	The channel, this is to allow the matrix element to be used to select the intermediates
inpart	The incoming particle.
opt	The option for what to calculate
outpart	The outgoing particles.

Definition at line 216 of file DecayPhaseSpaceMode.h.

unsigned int Herwig::DecayPhaseSpaceMode::numberChannels ( ) const [inline]

Number of channels.

Returns:: The number of channels.

Definition at line 103 of file DecayPhaseSpaceMode.h.

unsigned int Herwig::DecayPhaseSpaceMode::numberofParticles ( ) const [inline]

Number of external particles.

Returns:: The number of external particles.

Definition at line 97 of file DecayPhaseSpaceMode.h.

void Herwig::DecayPhaseSpaceMode::persistentInput	(	PersistentIStream &	is,
		int	version
	)

Function used to read in object persistently.

Parameters:

is	the persistent input stream read from.
version	the version number of the object when written.

Reimplemented from ThePEG::Interfaced.

void Herwig::DecayPhaseSpaceMode::persistentOutput ( PersistentOStream & os ) const

Function used to write out object persistently.

Parameters:

os	the persistent output stream written to.

Reimplemented from ThePEG::Interfaced.

void Herwig::DecayPhaseSpaceMode::resetIntermediate	(	int	ichan,
		tcPDPtr	part,
		Energy	mass,
		Energy	width
	)		`[inline]`

Reset the properties of one of the intermediate particles.

Only a specific channel is reset.

Parameters:

ichan	The channel to reset.
part	The ParticleData object of the particle to reset
mass	The mass of the intermediate.
width	The width of gthe intermediate.

Definition at line 122 of file DecayPhaseSpaceMode.h.

void Herwig::DecayPhaseSpaceMode::resetIntermediate	(	tcPDPtr	part,
		Energy	mass,
		Energy	width
	)		`[inline]`

Reset the properties of one of the intermediate particles.

All the channels are reset.

Parameters:

part	The ParticleData object of the particle to reset
mass	The mass of the intermediate.
width	The width of gthe intermediate.

Definition at line 134 of file DecayPhaseSpaceMode.h.

int Herwig::DecayPhaseSpaceMode::selectChannel	(	const Particle &	inpart,
		ParticleVector &	outpart
	)		const `[inline, protected]`

Select which channel to use to output the particles.

Parameters:

inpart	The incoming particles.
outpart	The outgoing particles.

Definition at line 238 of file DecayPhaseSpaceMode.h.

References ThePEG::UseRandom::rnd().

void Herwig::DecayPhaseSpaceMode::setIntegrate	(	int	iter,
		int	points,
		int	ntry
	)		`[inline, protected]`

Set the integration parameters.

Parameters:

iter	The number of iterations to use for initialization.
points	The number of points to use for each iteration during initialization.
ntry	The number of tries to generate a decay.

Definition at line 190 of file DecayPhaseSpaceMode.h.

void Herwig::DecayPhaseSpaceMode::setMaxWeight ( double wgt ) const [inline]

Set the maximum weight for the decay.

Parameters:

wgt	The maximum weight.

Definition at line 149 of file DecayPhaseSpaceMode.h.

void Herwig::DecayPhaseSpaceMode::setPartialWidth ( int in ) [inline, protected]

Set the partial width to use for normalization.

This is the partial width in the WidthGenerator object.

Parameters:

in	The partial width to use.

Definition at line 201 of file DecayPhaseSpaceMode.h.

void Herwig::DecayPhaseSpaceMode::setWeights ( const vector< double > & in ) const [inline]

Set the weights for the different channels.

Parameters:

in	The weights for the different channels in the multi-channel approach.

Definition at line 162 of file DecayPhaseSpaceMode.h.

Energy Herwig::DecayPhaseSpaceMode::weight	(	bool	cc,
		int &	ichan,
		const Particle &	in,
		ParticleVector &	particles,
		bool	first,
		bool	onShell = `false`
	)		const `[inline, protected]`

Return the weight for a given phase-space point.

Parameters:

cc	Whether we are generating the mode specified or the charge conjugate mode.
ichan	The channel to generate the weight for.
in	The incoming particle.
particles	The outgoing particles.
first	Whether or not this is the first call for initialisation

Returns:: The weight.

Definition at line 268 of file DecayPhaseSpaceMode.h.

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

DecayPhaseSpaceMode.h

Public Member Functions

Static Public Member Functions

Protected Member Functions

Private Member Functions

Private Attributes

Static Private Attributes

Friends

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation