ClusterCollapser is a general StepHandler which can be called anywhere in the event generation (typically as a pre-handler to the hadronization or a post-hadnler to the cascade) to find colour-less clusters of partons which are deemed to have to small invariant mass to be hadronized in the normal way. More...

#include <ClusterCollapser.h>

Inheritance diagram for ThePEG::ClusterCollapser:

[legend]

Public Types
typedef Ptr< FlavourGenerator >::pointer	FlavGenPtr
	Declare a pointer to a FlavourGenerator object.

typedef multimap< Energy, ColourSinglet >	SingletMap
	Declare a multimap of singlets indexed by their mass.

Public Types inherited from ThePEG::InterfacedBase
enum	InitState { initializing = -1 , uninitialized = 0 , initialized = 1 , runready = 2 }
	Enumeration reflecting the state of an InterfacedBase object. More...

Public Types inherited from ThePEG::Pointer::ReferenceCounted
typedef unsigned int	CounterType
	The integer type used for counting.

Public Member Functions
Standard constructors and destructors.
	ClusterCollapser ()
	The default constructor.

virtual	~ClusterCollapser ()
	The destructor.

Public Member Functions inherited from ThePEG::StepHandler
virtual	~StepHandler ()
	The destructor.

tEHPtr	eventHandler () const
	Get a pointer to the EventHandler which made the last call to handle().

void	eventHandler (tEHPtr)
	Set a pointer to the EventHandler which made the last call to handle().

tStepPtr	newStep ()
	Return a pointer to a new step.

tStepPtr	currentStep ()
	If a new step has been created, return it, otherwise return the current step from the eventHandler().

Public Member Functions inherited from ThePEG::HandlerBaseT< UseRandom >
virtual	~HandlerBaseT ()
	Destructor.

double	rnd () const
	Return a simple flat random number in the range ]0,1[.

double	rnd (double xu) const
	Return a simple flat random number in the range ]0,xu[.

double	rnd (double xl, double xu) const
	Return a simple flat random number in the range ]xl,xu[.

bool	rndbool () const
	Return true with 50% probability.

bool	rndbool (double p) const
	Return a true with probability p.

bool	rndbool (double p1, double p2) const
	Return a true with probability p1/(p1+p2).

int	rndsign (double p1, double p2, double p3) const
	Return -1, 0, or 1 with relative probabilities p1, p2, p3.

int	rnd2 (double p0, double p1) const
	Return an integer \(i\) with probability p \(i\)/(p0+p1).

int	rnd3 (double p0, double p1, double p2) const
	Return an integer \(i\) with probability p \(i\)/(p0+p1+p2).

int	rnd4 (double p0, double p1, double p2, double p3) const
	Return an integer/ \(i\) with probability p \(i\)(p0+p1+p2+p3).

long	irnd (long xu=2) const
	Return a simple flat random integrer number in the range [0,xu[.

long	irnd (long xl, long xu) const
	Return a simple flat random integrer number in the range [xl,xu[.

const StandardModelBase &	SM () const
	Return a reference to the object containing the standard model parameters for this run.

tSMPtr	standardModel () const
	Return a pointer to the object containing the standard model parameters for this run.

Public Member Functions inherited from ThePEG::Interfaced
virtual	~Interfaced ()
	Empty virtual destructor.

virtual bool	defaultInit ()
	Functions which are to be used during the actual event generation, after the setup is complete.

PPtr	getParticle (PID) const
	Create a new Particle instance given a id number.

PDPtr	getParticleData (PID) const
	Return a pointer to the ParticleData object corresponding to the given id number.

bool	used () const
	Returns true if this object has actally been used.

void	useMe () const
	Should be called to indicate that this object has actually been used.

tEGPtr	generator () const
	Return a pointer to the EventGenerator controlling the run.

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.

Public Member Functions inherited from ThePEG::InterfacedBase
virtual	~InterfacedBase ()
	The virtual (empty) destructor;.

string	fullName () const
	Returns the full name of this object including its path, e.g.

string	name () const
	Returns the name of this object, without the path.

string	path () const
	Returns the path to this object including the trailing '/'.

string	comment () const
	Returns a comment assigned to this object.

void	setup (istream &is)
	Read setup info from a standard istream is.

void	update ()
	Calls the doupdate() function with recursion prevention.

void	init ()
	Calls the doinit() function with recursion prevention.

virtual bool	preInitialize () const
	Return true if this object needs to be initialized before all other objects (except those for which this function also returns true).

void	initrun ()
	Calls the doinitrun() function with recursion prevention.

void	finish ()
	Calls the dofinish() function with recursion prevention.

void	touch ()
	This function should be called every time something in this object has changed in a way that a sanity check with update() is needed.

void	reset ()
	Set the state of this object to uninitialized.

void	clear ()
	Calls reset() and unTouch().

InitState	state () const
	Return the state of initialization of this object.

bool	locked () const
	Return true if the BaseRepository is not allowed to change the state of this object.

bool	touched () const
	Return true if the state of this object has been changed since the last call to update().

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.

virtual void	debugme () const
	Print out debugging information for this object on std::cerr.

Public Member Functions inherited from ThePEG::Base
virtual	~Base ()
	The virtual destructor.

void	debug () const
	Print out debugging information for this object on std::cerr.

virtual void	debugme () const
	Print out debugging information for this object on std::cerr.

Public Member Functions inherited from ThePEG::Pointer::ReferenceCounted
CounterType	referenceCount () const
	Return the reference count.

Public Member Functions inherited from ThePEG::Named
	Named (const string &newName=string())
	Constructor with name.

	Named (const Named &)=default
	Explicit default copy-constructor (too avoid compiler warnings)

const string &	name () const
	Return name.

bool	operator== (const Named &other) const
	Test for equality.

bool	operator< (const Named &other) const
	Lexicographical comparison.

Clone Methods.
Energy	theEnergyCut
	Energy cut.

int	theNTry2
	The number of attempts to collapse a cluster into two particles, before it is collapsed into one particle.

FlavGenPtr	flavGen
	The flavour generator object to use to combine quarks and diqurks into hadrons.

Exception::Severity	errorlevel
	How should we respond to errors? 0 means do nothing, ie.

double	pStrange
	The relative probability to produce a s-sbar pair in a split as compared to a u-ubar or d-dbar pair.

static ClassDescription< ClusterCollapser >	initClusterCollapser
	Describe a concrete class with persistent data.

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.

ClusterCollapser &	operator= (const ClusterCollapser &)=delete
	Private and non-existent assignment operator.

Virtual functions required by the StepHandler class.
virtual void	handle (EventHandler &eh, const tPVector &tagged, const Hint &hint)
	The main function called by the EventHandler class to perform a step.

virtual vector< ColourSinglet >	collapse (tPVector tagged, tStepPtr newstep)
	Perform all necessary collapses.

virtual SingletMap	getSinglets (const tPVector &tagged) const
	Go through the tagged partons and extract all colour singlet combination of partons.

virtual ColourSinglet	splitDiQuarkJunction (ColourSinglet &cs, tStepPtr newStep) const
	If a singlet contains at least one diquark and a junction, split the diquark and split off a new colour singlet.

virtual ColourSinglet	splitDiDiQuark (ColourSinglet &cs, tStepPtr newStep) const
	If a singlet contains a simple string with diquarks in both ends, split them into quarks and split off a new colour singlet.

Energy	cut () const
	If the invariant mass of a cluster, minus the constituent masses of its partons is below this cut, it will be collapsed into one or two particles.

int	nTry2 () const
	The number of attempts to collapse a cluster into two particles, before it is collapsed into one particle.

virtual tcPDPtr	pickFlavour () const
	Pick a random flavour.

static bool	diQuarkJunction (const ColourSinglet &cs)
	Returns true iff the given singlet contains a junction and at least one diquark.

static bool	diDiQuark (const ColourSinglet &cs)
	Returns true iff the given singlet contains one string piece with diquarks in both ends.

static Energy	mass (const ColourSinglet &cl)
	Return the invariant mass of a cluster minus the constituent masses of its partons.

static void	insert (SingletMap &mmap, const ColourSinglet &cl)
	Insert a ColourSinglet object in a SingletMap.

virtual void	collapse (tStepPtr newStep, const ColourSinglet &cs, const tPVector &tagged) const
	Perform the actual collapse of a cluster into one hadron.

virtual bool	collapse2 (tStepPtr newStep, const ColourSinglet &cs) const
	Perform the actual collapse of a cluster into two hadrons.

virtual tPVector	getCompensators (Energy mh, const ColourSinglet &cs, const tPVector &tagged, tStepPtr newStep) const
	Get particles for compensation.

virtual tcPDPtr	getHadron (const ColourSinglet &cs) const
	Return a hadron into which the given cluster may collapse.

virtual tcPDPair	getHadrons (const ColourSinglet &cs) const
	Return a pair of hadrons into which the given cluster may collapse.

void	updateTagged (tPVector &tagged) const
	Uptate the vector of particles and remove partons which have already collapsed and insert their children instead.

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 void	Init ()
	Standard Init function used to initialize the interfaces.

Additional Inherited Members
Static Public Member Functions inherited from ThePEG::StepHandler
static void	Init ()
	Standard Init function used to initialize the interface.

Static Public Member Functions inherited from ThePEG::HandlerBase
static void	Init ()
	Standard Init function used to initialize the interface.

Static Public Member Functions inherited from ThePEG::Interfaced
static void	Init ()
	Standard Init function.

Static Public Member Functions inherited from ThePEG::InterfacedBase
static void	Init ()
	Standard Init function.

Static Public Member Functions inherited from ThePEG::Base
static void	Init ()
	The standard Init function used to initialize the interfaces.

Public Attributes inherited from ThePEG::Pointer::ReferenceCounted
const unsigned long	uniqueId
	The unique ID.

Protected Member Functions inherited from ThePEG::StepHandler
void	createNewStep ()
	Use the collision handler to create a new step.

Protected Member Functions inherited from ThePEG::Interfaced
void	reporeg (IBPtr object, string name) const
	Register the given object in the Repository with the given name in a subdirectory with the same name as this object.

template<typename PtrT >
bool	setDefaultReference (PtrT &ptr, string classname, string objectname)
	If the pointer, ptr, to an object is not set, create an object of class classname and register it with the Repository with the given objectname in a sib-directory with the same name as this object.

	Interfaced ()
	Protected default constructor.

	Interfaced (const string &newName)
	Protected constructor taking a name as argument.

	Interfaced (const Interfaced &i)
	Protected copy-constructor.

void	setGenerator (tEGPtr generator)
	Protected function to reset the generator pointer, required for automatic decayer generation in Herwig++ BSM models.

Protected Member Functions inherited from ThePEG::InterfacedBase
virtual void	readSetup (istream &is)
	Read setup info from a standard istream is.

virtual void	doupdate ()
	Check sanity of the object during the setup phase.

virtual void	doinit ()
	Initialize this object after the setup phase before saving an EventGenerator to disk.

virtual void	doinitrun ()
	Initialize this object.

virtual void	dofinish ()
	Finalize this object.

virtual IVector	getReferences ()
	Return a vector of all pointers to Interfaced objects used in this object.

virtual void	rebind (const TranslationMap &)
	Rebind pointer to other Interfaced objects.

	InterfacedBase ()
	Protected default constructor.

	InterfacedBase (string newName)
	Protected constructor with the name given as argument.

	InterfacedBase (const InterfacedBase &i)
	Protected copy-constructor.

Protected Member Functions inherited from ThePEG::Pointer::ReferenceCounted
	ReferenceCounted ()
	Default constructor.

	ReferenceCounted (const ReferenceCounted &)
	Copy-constructor.

ReferenceCounted &	operator= (const ReferenceCounted &)
	Assignment.

Protected Member Functions inherited from ThePEG::Named
const Named &	operator= (const Named &other)
	Assignment.

const string &	name (const string &newName)
	Set new name.

Static Protected Member Functions inherited from ThePEG::Interfaced
static void	registerRepository (IBPtr)
	Register an Interfaced object with the Repository.

static void	registerRepository (IBPtr, string newName)
	Register an Interfaced object with the Repository, giving it a name.

Detailed Description

ClusterCollapser is a general StepHandler which can be called anywhere in the event generation (typically as a pre-handler to the hadronization or a post-hadnler to the cascade) to find colour-less clusters of partons which are deemed to have to small invariant mass to be hadronized in the normal way.

Instead these clusters are allowed to collapse into hadrons. Possible energy imbalance du to the clustering is compensated by shifting the momenta of nearby particles.

See also: The interfaces defined for ClusterCollapser.

Definition at line 35 of file ClusterCollapser.h.

Member Typedef Documentation

◆ FlavGenPtr

typedef Ptr<FlavourGenerator>::pointer ThePEG::ClusterCollapser::FlavGenPtr

Declare a pointer to a FlavourGenerator object.

Definition at line 40 of file ClusterCollapser.h.

◆ SingletMap

typedef multimap<Energy,ColourSinglet> ThePEG::ClusterCollapser::SingletMap

Declare a multimap of singlets indexed by their mass.

Definition at line 43 of file ClusterCollapser.h.

Constructor & Destructor Documentation

◆ ClusterCollapser()

ThePEG::ClusterCollapser::ClusterCollapser ( )

inline

The default constructor.

Definition at line 52 of file ClusterCollapser.h.

Member Function Documentation

◆ clone()

virtual IBPtr ThePEG::ClusterCollapser::clone ( ) const

protectedvirtual

Make a simple clone of this object.

Returns: a pointer to the new object.

Implements ThePEG::InterfacedBase.

◆ collapse() [1/2]

virtual vector< ColourSinglet > ThePEG::ClusterCollapser::collapse	(	tPVector	tagged,
		tStepPtr	newstep
	)

virtual

Perform all necessary collapses.

Return the uncollapsed clusters.

◆ collapse() [2/2]

virtual void ThePEG::ClusterCollapser::collapse	(	tStepPtr	newStep,
		const ColourSinglet &	cs,
		const tPVector &	tagged
	)		const

protectedvirtual

Perform the actual collapse of a cluster into one hadron.

Add the produced hadron to the given step as decay products of the partons in the cluster. The tagged particles are used for momentum compensation.

◆ collapse2()

virtual bool ThePEG::ClusterCollapser::collapse2	(	tStepPtr	newStep,
		const ColourSinglet &	cs
	)		const

protectedvirtual

Perform the actual collapse of a cluster into two hadrons.

Add the produced hadrons to the given step as decay products of the partons in the cluster. The tagged particles are used for momentum compensation.

Returns: false if the collapse failed in some way.

◆ cut()

Energy ThePEG::ClusterCollapser::cut ( ) const

inline

If the invariant mass of a cluster, minus the constituent masses of its partons is below this cut, it will be collapsed into one or two particles.

Definition at line 127 of file ClusterCollapser.h.

References theEnergyCut.

◆ fullclone()

virtual IBPtr ThePEG::ClusterCollapser::fullclone ( ) const

protectedvirtual

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.

◆ getCompensators()

virtual tPVector ThePEG::ClusterCollapser::getCompensators	(	Energy	mh,
		const ColourSinglet &	cs,
		const tPVector &	tagged,
		tStepPtr	newStep
	)		const

protectedvirtual

Get particles for compensation.

Look through the tagged vector for particles (which are not in the colour singlet cs) which can be used to compensate momentum when cs collapses into a hadron with mass mh. These partons are then copied into the new step so that their momentum can be changed and then returned.

◆ getSinglets()

virtual SingletMap ThePEG::ClusterCollapser::getSinglets ( const tPVector & tagged ) const

virtual

Go through the tagged partons and extract all colour singlet combination of partons.

Order them in invariant mass (minus the constituent masses of the partons).

◆ handle()

virtual void ThePEG::ClusterCollapser::handle	(	EventHandler &	eh,
		const tPVector &	tagged,
		const Hint &	hint
	)

virtual

The main function called by the EventHandler class to perform a step.

This function simply calls the collapse() function.

Parameters

eh	the EventHandler in charge of the Event generation.
tagged	if not empty these are the only particles which should be considered by the StepHandler.
hint	a Hint object with possible information from previously performed steps.

Exceptions

Veto	if the StepHandler requires the current step to be discarded.
Stop	if the generation of the current Event should be stopped after this call.
Exception	if something goes wrong.

Implements ThePEG::StepHandler.

◆ nTry2()

int ThePEG::ClusterCollapser::nTry2 ( ) const

inline

The number of attempts to collapse a cluster into two particles, before it is collapsed into one particle.

Definition at line 133 of file ClusterCollapser.h.

References theNTry2.

◆ persistentInput()

void ThePEG::ClusterCollapser::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.

◆ persistentOutput()

void ThePEG::ClusterCollapser::persistentOutput ( PersistentOStream & os ) const

Function used to write out object persistently.

Parameters

os	the persistent output stream written to.

◆ pickFlavour()

virtual tcPDPtr ThePEG::ClusterCollapser::pickFlavour ( ) const

virtual

Pick a random flavour.

Default version picks u,d or s with ratio 3:3:1.

Member Data Documentation

◆ errorlevel

Exception::Severity ThePEG::ClusterCollapser::errorlevel

protected

How should we respond to errors? 0 means do nothing, ie.

the cluster will not be collapsed, or the momentum will not be consterved. Otherwise the severity will be what is defined in the class Exception.

Definition at line 278 of file ClusterCollapser.h.

◆ flavGen

FlavGenPtr ThePEG::ClusterCollapser::flavGen

private

The flavour generator object to use to combine quarks and diqurks into hadrons.

Definition at line 268 of file ClusterCollapser.h.

◆ initClusterCollapser

ClassDescription<ClusterCollapser> ThePEG::ClusterCollapser::initClusterCollapser

staticprivate

Describe a concrete class with persistent data.

Definition at line 291 of file ClusterCollapser.h.

◆ pStrange

double ThePEG::ClusterCollapser::pStrange

protected

The relative probability to produce a s-sbar pair in a split as compared to a u-ubar or d-dbar pair.

Definition at line 284 of file ClusterCollapser.h.

◆ theEnergyCut

Energy ThePEG::ClusterCollapser::theEnergyCut

private

Energy cut.

If the invariant mass of a cluster, minus the constituent masses of its partons is below this cut, it will be collapsed into one or two particles.

Definition at line 256 of file ClusterCollapser.h.

Referenced by cut().

◆ theNTry2

int ThePEG::ClusterCollapser::theNTry2

private

The number of attempts to collapse a cluster into two particles, before it is collapsed into one particle.

Definition at line 262 of file ClusterCollapser.h.

Referenced by nTry2().

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

ClusterCollapser.h

Public Types

Public Member Functions

Clone Methods.

Virtual functions required by the StepHandler class.

Functions used by the persistent I/O system.

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ FlavGenPtr

◆ SingletMap

Constructor & Destructor Documentation

◆ ClusterCollapser()

Member Function Documentation

◆ clone()

◆ collapse() [1/2]

◆ collapse() [2/2]

◆ collapse2()

◆ cut()

◆ fullclone()

◆ getCompensators()

◆ getSinglets()

◆ handle()

◆ nTry2()

◆ persistentInput()

◆ persistentOutput()

◆ pickFlavour()

Member Data Documentation

◆ errorlevel

◆ flavGen

◆ initClusterCollapser

◆ pStrange

◆ theEnergyCut

◆ theNTry2