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Herwig 7.3.0
Herwig::WeakPartonicDecayer Class Reference

The WeakPartonicDecayer class is designed to replace the HeavyDecayer class which implements the partonic decays of hadrons containing a heavy quark in the same way as in FORTRAN Herwig. More...

#include <WeakPartonicDecayer.h>

Inheritance diagram for Herwig::WeakPartonicDecayer:

Public Member Functions

 WeakPartonicDecayer ()
 The default constructor.
 
virtual bool accept (tcPDPtr parent, const tPDVector &children) const
 Check if this decayer can perfom the decay for a particular mode.
 
virtual ParticleVector decay (const Particle &parent, const tPDVector &children) const
 Perform the decay of the particle to the specified decay products.
 
virtual void dataBaseOutput (ofstream &os, bool header) const
 Output the setup information for the particle database.
 
- Public Member Functions inherited from Herwig::PartonicDecayerBase
 PartonicDecayerBase ()
 The default constructor.
 
virtual ParticleVector decay (const DecayMode &dm, const Particle &p) const
 Perform a decay for a given DecayMode and a given Particle instance.
 
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 Herwig::HwDecayerBase
 HwDecayerBase ()
 The default constructor.
 
virtual bool accept (const DecayMode &dm) const
 Check if this decayer can perfom the decay specified by the given decay mode.
 
virtual POWHEGType hasPOWHEGCorrection ()
 Has a POWHEG style correction.
 
virtual bool hasMECorrection ()
 Has an old fashioned ME correction.
 
virtual void initializeMECorrection (RealEmissionProcessPtr, double &, double &)
 Initialize the ME correction.
 
virtual RealEmissionProcessPtr applyHardMatrixElementCorrection (RealEmissionProcessPtr)
 Apply the hard matrix element correction to a given hard process or decay.
 
virtual bool softMatrixElementVeto (PPtr parent, PPtr progenitor, const bool &fs, const Energy &highestpT, const vector< tcPDPtr > &ids, const double &z, const Energy &scale, const Energy &pT)
 Apply the soft matrix element correction.
 
virtual RealEmissionProcessPtr generateHardest (RealEmissionProcessPtr)
 Apply the POWHEG style correction.
 
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.
 
bool initialize () const
 Access to the initialize variable.
 
bool databaseOutput () const
 Access the database output variable.
 
- Public Member Functions inherited from ThePEG::Decayer
void persistentOutput (PersistentOStream &os) const
 
void persistentInput (PersistentIStream &is, int version)
 
virtual bool accept (const DecayMode &dm) const=0
 
virtual bool needsFullStep () const
 
virtual ParticleVector decay (const DecayMode &dm, const Particle &p) const=0
 
virtual ParticleVector decay (const DecayMode &dm, const Particle &p, Step &step) const
 
virtual double brat (const DecayMode &dm, const ParticleData &pd, double oldbrat) const
 
virtual double brat (const DecayMode &dm, const Particle &p, double oldbrat) const
 
virtual ParticleVector getChildren (const DecayMode &dm, const Particle &parent) const
 
virtual void finalBoost (const Particle &parent, const ParticleVector &children) const
 
virtual void setScales (const Particle &parent, const ParticleVector &children) const
 
Ptr< Amplitude >::pointer amplitude () const
 
- Public Member Functions inherited from ThePEG::HandlerBaseT< UseRandom >
double rnd () const
 
double rnd (double xu) const
 
double rnd (double xl, double xu) const
 
bool rndbool () const
 
bool rndbool (double p) const
 
bool rndbool (double p1, double p2) const
 
int rndsign (double p1, double p2, double p3) const
 
int rnd2 (double p0, double p1) const
 
int rnd3 (double p0, double p1, double p2) const
 
int rnd4 (double p0, double p1, double p2, double p3) const
 
long irnd (long xu=2) const
 
long irnd (long xl, long xu) const
 
const StandardModelBaseSM () const
 
tSMPtr standardModel () const
 
- Public Member Functions inherited from ThePEG::Interfaced
virtual bool defaultInit ()
 
PPtr getParticle (PID) const
 
PDPtr getParticleData (PID) const
 
bool used () const
 
void useMe () const
 
tEGPtr generator () const
 
void persistentOutput (PersistentOStream &os) const
 
void persistentInput (PersistentIStream &is, int version)
 
PPtr getParticle (PID) const
 
PDPtr getParticleData (PID) const
 
bool used () const
 
void useMe () const
 
tEGPtr generator () const
 
- Public Member Functions inherited from ThePEG::InterfacedBase
string fullName () const
 
string name () const
 
string path () const
 
string comment () const
 
void setup (istream &is)
 
void update ()
 
void init ()
 
virtual bool preInitialize () const
 
void initrun ()
 
void finish ()
 
void touch ()
 
void reset ()
 
void clear ()
 
InitState state () const
 
bool locked () const
 
bool touched () const
 
virtual IBPtr fullclone () const
 
void persistentOutput (PersistentOStream &os) const
 
void persistentInput (PersistentIStream &is, int version)
 
virtual void debugme () const
 
void update ()
 
void init ()
 
virtual bool preInitialize () const
 
void initrun ()
 
void finish ()
 
void touch ()
 
void reset ()
 
void clear ()
 
InitState state () const
 
bool locked () const
 
bool touched () const
 
virtual IBPtr fullclone () const
 
- Public Member Functions inherited from ThePEG::Base
void debug () const
 
virtual void debugme () const
 
- Public Member Functions inherited from ThePEG::Pointer::ReferenceCounted
CounterType referenceCount () const
 
- Public Member Functions inherited from ThePEG::Named
 Named (const string &newName=string())
 
 Named (const Named &)=default
 
const string & name () const
 
bool operator== (const Named &other) const
 
bool operator< (const Named &other) const
 

Clone Methods.

int MECode
 The code for the matrix element being used.
 
double _radprob
 Probablilty of radiation giving an extra quark-antiquark pair.
 
unsigned int _maxtry
 Maximum number of tries to generate the kinematics.
 
double _threemax
 Maximum weight for three-body decays.
 
double _fourmax
 Maximum weight for four-body decays.
 
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.
 
double threeBodyMatrixElement (tcPDPtr dec, const RhoDMatrix &rhoin, Lorentz5Momentum &pdec, ParticleVector &partons) const
 Compute \(\rho\) matrix for tau decay in three body case.
 
double fourBodyMatrixElement (Lorentz5Momentum &p0, Lorentz5Momentum &p1, Lorentz5Momentum &p2, Lorentz5Momentum &p3, Lorentz5Momentum &pg, bool Wcol, bool &initial) const
 Four body matrix element for weak decay including an extra gluon.
 
WeakPartonicDecayeroperator= (const WeakPartonicDecayer &)=delete
 The assignment operator is private and must never be called.
 

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 ()
 The standard Init function used to initialize the interfaces.
 
static double VAWt (Energy2, Energy2, Energy2, InvEnergy4)
 Weighting of phase space for V-A matrix elements.
 

Additional Inherited Members

- Public Types inherited from Herwig::HwDecayerBase
enum  POWHEGType { No , ISR , FSR , Both }
 Virtual members to be overridden by inheriting classes which implement hard corrections. More...
 
- Public Types inherited from ThePEG::InterfacedBase
enum  InitState
 
- Public Types inherited from ThePEG::Pointer::ReferenceCounted
typedef unsigned int CounterType
 
- Static Public Member Functions inherited from Herwig::PartonicDecayerBase
static void Init ()
 The standard Init function used to initialize the interfaces.
 
- Static Public Member Functions inherited from Herwig::HwDecayerBase
static void Init ()
 The standard Init function used to initialize the interfaces.
 
- Static Public Member Functions inherited from ThePEG::Decayer
static void Init ()
 
static ParticleVector DecayParticle (tPPtr parent, Step &step, long maxtry=1000)
 
- Static Public Member Functions inherited from ThePEG::HandlerBase
static void Init ()
 
- Static Public Member Functions inherited from ThePEG::Interfaced
static void Init ()
 
- Static Public Member Functions inherited from ThePEG::InterfacedBase
static void Init ()
 
- Static Public Member Functions inherited from ThePEG::Base
static void Init ()
 
- Public Attributes inherited from ThePEG::InterfacedBase
 initializing
 
 uninitialized
 
 initialized
 
 runready
 
- Public Attributes inherited from ThePEG::Pointer::ReferenceCounted
const unsigned long uniqueId
 
- Protected Member Functions inherited from Herwig::PartonicDecayerBase
virtual void doinit ()
 Initialize this object after the setup phase before saving an EventGenerator to disk.
 
bool duplicateMode (const Particle &parent, const vector< tPPtr > &hadrons) const
 Check hadrons produced in a partonic hadron decay do not reproduce an inclusive mode.
 
PVector shower (const Particle &parent, ParticleVector &partons) const
 Perform the parton shower.
 
bool timeLikeShower (tShowerParticlePtr particle, Branching fb, bool first, PVector &output) const
 
- Protected Member Functions inherited from Herwig::HwDecayerBase
virtual void dofinish ()
 Finalize this object.
 
void fixRho (RhoDMatrix &) const
 Set rho to be diagonal if no correlations.
 
- Protected Member Functions inherited from ThePEG::Interfaced
void reporeg (IBPtr object, string name) const
 
bool setDefaultReference (PtrT &ptr, string classname, string objectname)
 
 Interfaced (const string &newName)
 
 Interfaced (const Interfaced &i)
 
void setGenerator (tEGPtr generator)
 
- Protected Member Functions inherited from ThePEG::InterfacedBase
virtual void readSetup (istream &is)
 
virtual void doupdate ()
 
virtual void doinit ()
 
virtual void doinitrun ()
 
virtual void dofinish ()
 
virtual IVector getReferences ()
 
virtual void rebind (const TranslationMap &)
 
virtual IBPtr clone () const=0
 
 InterfacedBase (string newName)
 
 InterfacedBase (const InterfacedBase &i)
 
virtual void readSetup (istream &is)
 
virtual void doupdate ()
 
virtual void doinit ()
 
virtual void doinitrun ()
 
virtual void dofinish ()
 
virtual IVector getReferences ()
 
virtual void rebind (const TranslationMap &)
 
- Protected Member Functions inherited from ThePEG::Pointer::ReferenceCounted
 ReferenceCounted (const ReferenceCounted &)
 
ReferenceCountedoperator= (const ReferenceCounted &)
 
- Protected Member Functions inherited from ThePEG::Named
const Namedoperator= (const Named &other)
 
const string & name (const string &newName)
 
- Static Protected Member Functions inherited from ThePEG::Interfaced
static void registerRepository (IBPtr)
 
static void registerRepository (IBPtr, string newName)
 

Detailed Description

The WeakPartonicDecayer class is designed to replace the HeavyDecayer class which implements the partonic decays of hadrons containing a heavy quark in the same way as in FORTRAN Herwig.

There are a number of major changes

  • The helicity formalism is used for the decays so that the \(\tau\) lepton gets the correct correlations.
  • The particles produced directly by the hadronisation, i.e. the primary hadrons produced in cluster decay are checked to ensure that none of the exclusive modes are reproduced.
  • Two body modes are allowed to try and force baryon production etc. In this case the colours of the partons are connected.
  • Three body modes of the form \(q g \bar{q}\) are supported for penguin mediated weak decays.

    Two types of matrix element are supported for this decay

    • MECode=0 flat-phase space.
    • MECode=100 V-A matrix element for the heavy quark decay in the spectator model.

    In addition for the two-body decays and the three-bopdy spectator decays using the weka V-A matrix element the option of adding an extra gluon to increase the multiplicity of hadrons is included

See also
HeavyDecayer

Definition at line 52 of file WeakPartonicDecayer.h.

Member Function Documentation

◆ accept()

virtual bool Herwig::WeakPartonicDecayer::accept ( tcPDPtr  parent,
const tPDVector children 
) const
virtual

Check if this decayer can perfom the decay for a particular mode.

Parameters
parentThe decaying particle
childrenThe decay products
Returns
true If this decayer can handle the given mode, otherwise false.

Implements Herwig::PartonicDecayerBase.

◆ clone()

virtual IBPtr Herwig::WeakPartonicDecayer::clone ( ) const
protectedvirtual

Make a simple clone of this object.

Returns
a pointer to the new object.

Implements ThePEG::InterfacedBase.

◆ dataBaseOutput()

virtual void Herwig::WeakPartonicDecayer::dataBaseOutput ( ofstream &  os,
bool  header 
) const
virtual

Output the setup information for the particle database.

Parameters
osThe stream to output the information to
headerWhether or not to output the information for MySQL

Reimplemented from Herwig::PartonicDecayerBase.

◆ decay()

virtual ParticleVector Herwig::WeakPartonicDecayer::decay ( const Particle parent,
const tPDVector children 
) const
virtual

Perform the decay of the particle to the specified decay products.

Parameters
parentThe decaying particle
childrenThe decay products
Returns
a ParticleVector containing the decay products.

Implements Herwig::PartonicDecayerBase.

◆ fourBodyMatrixElement()

double Herwig::WeakPartonicDecayer::fourBodyMatrixElement ( Lorentz5Momentum &  p0,
Lorentz5Momentum &  p1,
Lorentz5Momentum &  p2,
Lorentz5Momentum &  p3,
Lorentz5Momentum &  pg,
bool  Wcol,
bool &  initial 
) const
protected

Four body matrix element for weak decay including an extra gluon.

Parameters
p0Momentum of decaying quark
p1Momentum of connected decay product
p2Momentum of first parton from W decay
p3Momentum of second parton from W decay
pgMomentum of gluon from W decay
WcolWhether or not W products are coloured
initialWhether the radiation is from the decaying quark/first decay product or W decay products

◆ fullclone()

virtual IBPtr Herwig::WeakPartonicDecayer::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.

◆ Init()

static void Herwig::WeakPartonicDecayer::Init ( )
static

The standard Init function used to initialize the interfaces.

Called exactly once for each class by the class description system before the main function starts or when this class is dynamically loaded.

◆ operator=()

WeakPartonicDecayer & Herwig::WeakPartonicDecayer::operator= ( const WeakPartonicDecayer )
privatedelete

The assignment operator is private and must never be called.

In fact, it should not even be implemented.

◆ persistentInput()

void Herwig::WeakPartonicDecayer::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.

◆ persistentOutput()

void Herwig::WeakPartonicDecayer::persistentOutput ( PersistentOStream os) const

Function used to write out object persistently.

Parameters
osthe persistent output stream written to.

◆ threeBodyMatrixElement()

double Herwig::WeakPartonicDecayer::threeBodyMatrixElement ( tcPDPtr  dec,
const RhoDMatrix rhoin,
Lorentz5Momentum &  pdec,
ParticleVector partons 
) const
protected

Compute \(\rho\) matrix for tau decay in three body case.

Parameters
decParticleData object of decaying quark
rhoinSpin density matrix for the decaying quark
pdecThe momentum of the decaying particle
partonsThe partons produced

Member Data Documentation

◆ _fourmax

double Herwig::WeakPartonicDecayer::_fourmax
private

Maximum weight for four-body decays.

Definition at line 195 of file WeakPartonicDecayer.h.

◆ _maxtry

unsigned int Herwig::WeakPartonicDecayer::_maxtry
private

Maximum number of tries to generate the kinematics.

Definition at line 185 of file WeakPartonicDecayer.h.

◆ _radprob

double Herwig::WeakPartonicDecayer::_radprob
private

Probablilty of radiation giving an extra quark-antiquark pair.

Definition at line 180 of file WeakPartonicDecayer.h.

◆ _threemax

double Herwig::WeakPartonicDecayer::_threemax
private

Maximum weight for three-body decays.

Definition at line 190 of file WeakPartonicDecayer.h.

◆ MECode

int Herwig::WeakPartonicDecayer::MECode
private

The code for the matrix element being used.

Definition at line 175 of file WeakPartonicDecayer.h.


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