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ThePEG  2.1.0
ThePEG::ClusterCollapser Class Reference

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:

Public Types

typedef Ptr< FlavourGenerator >::pointer FlavGenPtr
 Declare a pointer to a FlavourGenerator object. More...
 
typedef multimap< Energy, ColourSingletSingletMap
 Declare a multimap of singlets indexed by their mass. More...
 
- 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

virtual vector< ColourSingletcollapse (tPVector tagged, tStepPtr newstep)
 Perform all necessary collapses. More...
 
virtual SingletMap getSinglets (const tPVector &tagged) const
 Go through the tagged partons and extract all colour singlet combination of partons. More...
 
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. More...
 
Standard constructors and destructors.
 ClusterCollapser ()
 The default constructor.
 
virtual ~ClusterCollapser ()
 The destructor.
 
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. More...
 
Functions used by the persistent I/O system.
void persistentOutput (PersistentOStream &os) const
 Function used to write out object persistently. More...
 
void persistentInput (PersistentIStream &is, int version)
 Function used to read in object persistently. More...
 
- 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. More...
 
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 >
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 StandardModelBaseSM () 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.
 
virtual ~HandlerBaseT ()
 Destructor.
 
- 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. More...
 
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. More...
 
void persistentOutput (PersistentOStream &os) const
 Function used to write out object persistently. More...
 
void persistentInput (PersistentIStream &is, int version)
 Function used to read in object persistently. More...
 
- 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. More...
 
string name () const
 Returns the name of this object, without the path.
 
string path () const
 Returns the path to this object including the trailing '/'. More...
 
string comment () const
 Returns a comment assigned to this object.
 
void setup (istream &is)
 Read setup info from a standard istream is. More...
 
virtual void debugme () const
 Print out debugging information for this object on std::cerr. More...
 
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). More...
 
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. More...
 
void persistentInput (PersistentIStream &is, int version)
 Function used to read in object persistently. More...
 
- 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. More...
 
- 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.
 
const string & name () const
 Return name.
 
bool operator== (const Named &other) const
 Test for equality.
 
bool operator< (const Named &other) const
 Lexicographical comparison.
 

Static Public Member Functions

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

Protected Member Functions

virtual void collapse (tStepPtr newStep, const ColourSinglet &cs, const tPVector &tagged) const
 Perform the actual collapse of a cluster into one hadron. More...
 
virtual bool collapse2 (tStepPtr newStep, const ColourSinglet &cs) const
 Perform the actual collapse of a cluster into two hadrons. More...
 
virtual tPVector getCompensators (Energy mh, const ColourSinglet &cs, const tPVector &tagged, tStepPtr newStep) const
 Get particles for compensation. More...
 
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.
 
Clone Methods.
virtual IBPtr clone () const
 Make a simple clone of this object. More...
 
virtual IBPtr fullclone () const
 Make a clone of this object, possibly modifying the cloned object to make it sane. More...
 
- 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. More...
 
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
 InterfacedBase ()
 Protected default constructor.
 
 InterfacedBase (string newName)
 Protected constructor with the name given as argument.
 
 InterfacedBase (const InterfacedBase &i)
 Protected copy-constructor.
 
virtual void readSetup (istream &is)
 Read setup info from a standard istream is. More...
 
virtual void doupdate ()
 Check sanity of the object during the setup phase. More...
 
virtual void doinit ()
 Initialize this object after the setup phase before saving an EventGenerator to disk. More...
 
virtual void doinitrun ()
 Initialize this object. More...
 
virtual void dofinish ()
 Finalize this object. More...
 
virtual IVector getReferences ()
 Return a vector of all pointers to Interfaced objects used in this object. More...
 
virtual void rebind (const TranslationMap &)
 Rebind pointer to other Interfaced objects. More...
 
- Protected Member Functions inherited from ThePEG::Pointer::ReferenceCounted
 ReferenceCounted ()
 Default constructor.
 
 ReferenceCounted (const ReferenceCounted &)
 Copy-constructor.
 
ReferenceCountedoperator= (const ReferenceCounted &)
 Assignment.
 
- Protected Member Functions inherited from ThePEG::Named
const Namedoperator= (const Named &other)
 Assignment.
 
const string & name (const string &newName)
 Set new name.
 

Protected Attributes

Exception::Severity errorlevel
 How should we respond to errors? 0 means do nothing, ie. More...
 
double pStrange
 The relative probability to produce a s-sbar pair in a split as compared to a u-ubar or d-dbar pair.
 

Private Member Functions

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

Private Attributes

Energy theEnergyCut
 Energy cut. More...
 
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.
 

Static Private Attributes

static ClassDescription< ClusterCollapserinitClusterCollapser
 Describe a concrete class with persistent data.
 

Additional Inherited Members

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

Declare a pointer to a FlavourGenerator object.

Definition at line 40 of file ClusterCollapser.h.

◆ SingletMap

Declare a multimap of singlets indexed by their mass.

Definition at line 43 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.

Referenced by nTry2().

◆ collapse() [1/2]

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

Perform all necessary collapses.

Return the uncollapsed clusters.

Referenced by ClusterCollapser(), and nTry2().

◆ 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.

Referenced by nTry2().

◆ 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.

Referenced by nTry2().

◆ 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.

Referenced by nTry2().

◆ 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).

Referenced by ClusterCollapser().

◆ 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
ehthe EventHandler in charge of the Event generation.
taggedif not empty these are the only particles which should be considered by the StepHandler.
hinta Hint object with possible information from previously performed steps.
Exceptions
Vetoif the StepHandler requires the current step to be discarded.
Stopif the generation of the current Event should be stopped after this call.
Exceptionif something goes wrong.

Implements ThePEG::StepHandler.

Referenced by ClusterCollapser().

◆ persistentInput()

void ThePEG::ClusterCollapser::persistentInput ( PersistentIStream is,
int  version 
)

Function used to read in object persistently.

Parameters
isthe persistent input stream read from.
versionthe version number of the object when written.

Referenced by nTry2().

◆ persistentOutput()

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

Function used to write out object persistently.

Parameters
osthe persistent output stream written to.

Referenced by nTry2().

◆ pickFlavour()

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

Pick a random flavour.

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

Referenced by nTry2().

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.

◆ 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().


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