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Herwig  7.2.1
Herwig::PerturbativeDecayer Class Reference

The PerturbativeDecayer class is the base class for perturbative decays in Herwig and implements the functuality for the POWHEG corrections. More...

#include <PerturbativeDecayer.h>

Inheritance diagram for Herwig::PerturbativeDecayer:

Classes

struct  DipoleType
 Type of dipole. More...
 

Public Member Functions

 PerturbativeDecayer ()
 The default constructor.
 
virtual POWHEGType hasPOWHEGCorrection ()
 Has a POWHEG style correction.
 
virtual RealEmissionProcessPtr generateHardest (RealEmissionProcessPtr)
 Member to generate the hardest emission in the POWHEG scheme.
 
virtual RealEmissionProcessPtr applyHardMatrixElementCorrection (RealEmissionProcessPtr)
 Apply the hard matrix element correction to a given hard process or decay.
 
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 Herwig::DecayIntegrator
 DecayIntegrator ()
 Default constructor.
 
virtual bool accept (tcPDPtr parent, const tPDVector &children) const
 Check if this decayer can perfom the decay for a particular mode. More...
 
virtual ParticleVector decay (const Particle &parent, const tPDVector &children) const
 For a given decay mode and a given particle instance, perform the decay and return the decay products. More...
 
virtual int modeNumber (bool &cc, tcPDPtr parent, const tPDVector &children) const =0
 Which of the possible decays is required. More...
 
int imode () const
 The mode being used for this decay.
 
void addMode (DecayPhaseSpaceModePtr mode, double maxwgt, const vector< double > wgts) const
 Add a phase-space mode to the list. More...
 
virtual double me2 (const int ichan, const Particle &part, const ParticleVector &decay, MEOption opt) const =0
 Return the matrix element squared for a given mode and phase-space channel. More...
 
DecayMEPtr ME () const
 The helicity amplitude matrix element for spin correlations.
 
virtual bool twoBodyMEcode (const DecayMode &, int &mecode, double &coupling) const
 Specify the $1\to2$ matrix element to be used in the running width calculation. More...
 
virtual WidthCalculatorBasePtr threeBodyMEIntegrator (const DecayMode &dm) const
 Method to return an object to calculate the 3 (or higher body) partial width. More...
 
virtual double threeBodyMatrixElement (const int imode, const Energy2 q2, const Energy2 s3, const Energy2 s2, const Energy2 s1, const Energy m1, const Energy m2, const Energy m3) const
 The matrix element to be integrated for the three-body decays as a function of the invariant masses of pairs of the outgoing particles. More...
 
virtual InvEnergy threeBodydGammads (const int imode, const Energy2 q2, const Energy2 s, const Energy m1, const Energy m2, const Energy m3) const
 The differential three body decay rate with one integral performed. More...
 
void setPartialWidth (const DecayMode &dm, int imode)
 Set the code for the partial width. More...
 
int findMode (const DecayMode &dm)
 Finds the phase-space mode corresponding to a given decay mode. More...
 
virtual void dataBaseOutput (ofstream &os, bool header) const
 Output the setup information for the particle database. More...
 
Energy epsilonPS () const
 Access to the epsilon parameter.
 
ParticleVector generatePhotons (const Particle &p, ParticleVector children)
 Members for the generation of QED radiation in the decays. More...
 
bool canGeneratePhotons ()
 check if photons can be generated in the decay
 
virtual double oneLoopVirtualME (unsigned int imode, const Particle &part, const ParticleVector &products)
 The one-loop virtual correction. More...
 
bool hasOneLoopME ()
 Whether or not the one loop matrix element is implemented.
 
virtual InvEnergy2 realEmissionME (unsigned int imode, const Particle &part, ParticleVector &products, unsigned int iemitter, double ctheta, double stheta, const LorentzRotation &rot1, const LorentzRotation &rot2)
 The real emission matrix element. More...
 
bool hasRealEmissionME ()
 Whether or not the real emission matrix element is implemented.
 
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 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. More...
 
virtual ParticleVector decay (const DecayMode &dm, const Particle &p) const
 Perform a decay for a given DecayMode and a given Particle instance. 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...
 
bool initialize () const
 Access to the initialize variable.
 
bool databaseOutput () const
 Access the database output variable.
 
virtual bool hasMECorrection ()
 Has an old fashioned ME correction.
 
virtual void initializeMECorrection (RealEmissionProcessPtr, double &, double &)
 Initialize the ME correction.
 
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. More...
 
- Public Member Functions inherited from ThePEG::Decayer
Ptr< Amplitude >::pointer amplitude () const
 
virtual bool needsFullStep () const
 
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
 
void persistentOutput (PersistentOStream &os) const
 
void persistentInput (PersistentIStream &is, int version)
 
virtual bool needsFullStep () const
 
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
 
void persistentOutput (PersistentOStream &os) const
 
void persistentInput (PersistentIStream &is, int version)
 
- Public Member Functions inherited from 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 StandardModelBase & SM () 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
 
void persistentOutput (PersistentOStream &os) const
 
void persistentInput (PersistentIStream &is, int version)
 
- Public Member Functions inherited from ThePEG::InterfacedBase
string fullName () const
 
string name () const
 
string path () const
 
string comment () const
 
void setup (istream &is)
 
virtual IBPtr fullclone () const
 
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
 
void persistentOutput (PersistentOStream &os) const
 
void persistentInput (PersistentIStream &is, int version)
 
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
 
void persistentOutput (PersistentOStream &os) const
 
void persistentInput (PersistentIStream &is, int version)
 
- Public Member Functions inherited from ThePEG::Base
void debug () 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
 

Static Public Member Functions

static void Init ()
 The standard Init function used to initialize the interfaces. More...
 
- Static Public Member Functions inherited from Herwig::DecayIntegrator
static void Init ()
 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. More...
 
- Static Public Member Functions inherited from ThePEG::Decayer
static ParticleVector DecayParticle (tPPtr parent, Step &step, long maxtry=1000)
 
static void Init ()
 
- 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 ()
 

Protected Types

enum  dipoleType {
  FFa, FFc, IFa, IFc,
  IFba, IFbc, FFg
}
 Type of dipole.
 
enum  phaseSpaceRegion {
  emissionFromB, emissionFromC, emissionFromA1, emissionFromA2,
  deadZone
}
 Phase-space region for an emission (assumes $a\to b,c$.
 

Protected Member Functions

virtual double matrixElementRatio (const Particle &inpart, const ParticleVector &decay2, const ParticleVector &decay3, MEOption meopt, ShowerInteraction inter)
 Calculate matrix element ratio $\frac{M^2}{\alpha_S}\frac{|\overline{\rm{ME}}_3|}{|\overline{\rm{ME}}_2|}$.
 
bool identifyDipoles (vector< DipoleType > &dipoles, PPtr &aProgenitor, PPtr &bProgenitor, PPtr &cProgenitor, ShowerInteraction inter) const
 Work out the type of process.
 
ShowerAlphaPtr alphaS ()
 Coupling for the generation of hard QCD radiation.
 
ShowerAlphaPtr alphaEM ()
 Coupling for the generation of hard QED radiation.
 
vector< Lorentz5Momentum > hardMomenta (PPtr in, PPtr emitter, PPtr spectator, const vector< DipoleType > &dipoles, int i, bool inDeadZone)
 Return the momenta including the hard emission.
 
bool calcMomenta (int j, Energy pT, double y, double phi, double &xg, double &xs, double &xe, double &xe_z, vector< Lorentz5Momentum > &particleMomenta)
 Calculate momenta of all the particles.
 
bool psCheck (const double xg, const double xs)
 Check the calculated momenta are physical.
 
pair< double, double > calculateDipole (const DipoleType &dipoleId, const Particle &inpart, const ParticleVector &decay3)
 Return dipole corresponding to the DipoleType dipoleId.
 
double dipoleSpinFactor (tcPDPtr emitter, double z)
 Return contribution to dipole that depends on the spin of the emitter.
 
double colourCoeff (tcPDPtr emitter, tcPDPtr spectator, tcPDPtr other, DipoleType dipole)
 Return the colour coefficient of the dipole.
 
void getColourLines (RealEmissionProcessPtr real)
 Set up the colour lines.
 
RealEmissionProcessPtr getHardEvent (RealEmissionProcessPtr born, bool inDeadZone, ShowerInteraction inter)
 Generate a hard emission.
 
bool inTotalDeadZone (double xg, double xs, const vector< DipoleType > &dipoles, int i)
 Is the $x_g,x_s$ point in the dead-zone for all the dipoles.
 
phaseSpaceRegion inInitialFinalDeadZone (double xg, double xa, double a, double c) const
 Is the $x_g,x_a$ point in the dead-zone for an initial-final colour connection.
 
phaseSpaceRegion inFinalFinalDeadZone (double xb, double xc, double b, double c) const
 Is the $x_b,x_c$ point in the dead-zone for a final-final colour connection.
 
bool useMEforT2 () const
 For me corrections use the shower or me for the T2 region.
 
const Energy & pT () const
 Access to the kinematics for inheriting classes. More...
 
const Energy & mb () const
 Mass of decaying particle.
 
const double & e () const
 Reduced mass of emitter child particle.
 
const double & s () const
 Reduced mass of spectator child particle.
 
const double & e2 () const
 Reduced mass of emitter child particle squared.
 
const double & s2 () const
 Reduced mass of spectator child particle squared.
 
- Protected Member Functions inherited from Herwig::DecayIntegrator
ParticleVector generate (bool inter, bool cc, const unsigned int &imode, const Particle &inpart) const
 Generate the momenta for the decay. More...
 
void imode (int in)
 Set the mode being use for this decay.
 
void ME (DecayMEPtr in) const
 Set the helicity matrix element for the decay.
 
void resetIntermediate (tcPDPtr part, Energy mass, Energy width)
 Reset the properities of all intermediates. More...
 
unsigned int numberModes () const
 Number of decay modes.
 
tDecayPhaseSpaceModePtr mode (unsigned int)
 Pointer to a mode.
 
tcDecayPhaseSpaceModePtr mode (unsigned int) const
 Pointer to a mode.
 
bool generateIntermediates () const
 Get whether or not the intermediates are included.
 
void generateIntermediates (bool in)
 Set whether or not the intermediates are included.
 
Energy initializePhaseSpaceMode (unsigned int imode, bool init, bool onShell=false) const
 Initialize the phase-space mode. More...
 
void hasOneLoopME (bool in)
 Whether or not the one loop matrix element is implemented.
 
void hasRealEmissionME (bool in)
 Whether or not the real emission matrix element is implemented.
 
void epsilonPS (Energy in)
 Set the epsilon parameter.
 
void clearModes ()
 Clear the models.
 
virtual void doinitrun ()
 Initialize this object to the begining of the run phase.
 
- Protected Member Functions inherited from Herwig::HwDecayerBase
void fixRho (RhoDMatrix &) const
 Set rho to be diagonal if no correlations.
 
virtual void dofinish ()
 Finalize this object. More...
 
- 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 IBPtr clone () const=0
 
 InterfacedBase (string newName)
 
 InterfacedBase (const InterfacedBase &i)
 
virtual void readSetup (istream &is)
 
virtual void doupdate ()
 
virtual void doinit ()
 
virtual IVector getReferences ()
 
virtual void rebind (const TranslationMap &)
 
virtual void readSetup (istream &is)
 
virtual void doupdate ()
 
virtual void doinit ()
 
virtual IVector getReferences ()
 
virtual void rebind (const TranslationMap &)
 
- Protected Member Functions inherited from ThePEG::Pointer::ReferenceCounted
 ReferenceCounted (const ReferenceCounted &)
 
ReferenceCountedoperator= (const 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)
 

Private Member Functions

PerturbativeDecayeroperator= (const PerturbativeDecayer &)=delete
 The assignment operator is private and must never be called. More...
 

Private Attributes

ShowerInteraction inter_
 Members for the generation of the hard radiation. More...
 
ShowerAlphaPtr alphaS_
 Coupling for the generation of hard QCD radiation.
 
ShowerAlphaPtr alphaEM_
 Coupling for the generation of hard QED radiation.
 
Energy pTmin_
 Minimum $p_T$.
 
bool useMEforT2_
 This flag determines whether the T2 region in the decay shower (JHEP12(2003)_045) is populated by the ME correction (true) or the shower from the decaying particle.
 
double C_
 Prefactor for the sampling.
 
double ymax_
 Maximum value for y.
 
unsigned int phaseOpt_
 Option for phase-space sampling.
 
Energy pT_
 Mmeber variables for the kinematics of the hard emission. More...
 
Energy mb_
 Mass of decaying particle.
 
double e_
 Reduced mass of emitter child particle.
 
double s_
 Reduced mass of spectator child particle.
 
double e2_
 Reduced mass of emitter child particle squared.
 
double s2_
 Reduced mass of spectator child particle squared.
 
double enhance_
 Enhancement prefactor for special cases.
 

Additional Inherited Members

- Public Types inherited from Herwig::DecayIntegrator
enum  MEOption { Initialize, Calculate, Terminate }
 Enum for the matrix element option.
 
- 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
 
- Public Attributes inherited from ThePEG::InterfacedBase
 initializing
 
 uninitialized
 
 initialized
 
 runready
 
- Public Attributes inherited from ThePEG::Pointer::ReferenceCounted
const unsigned long uniqueId
 
- Static Protected Member Functions inherited from ThePEG::Interfaced
static void registerRepository (IBPtr)
 
static void registerRepository (IBPtr, string newName)
 

Detailed Description

The PerturbativeDecayer class is the base class for perturbative decays in Herwig and implements the functuality for the POWHEG corrections.

See also
The interfaces defined for PerturbativeDecayer.

Definition at line 23 of file PerturbativeDecayer.h.

Member Function Documentation

◆ Init()

static void Herwig::PerturbativeDecayer::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=()

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

The assignment operator is private and must never be called.

In fact, it should not even be implemented.

◆ persistentInput()

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

Function used to write out object persistently.

Parameters
osthe persistent output stream written to.

◆ pT()

const Energy& Herwig::PerturbativeDecayer::pT ( ) const
inlineprotected

Access to the kinematics for inheriting classes.

Transverse momentum of the emission

Definition at line 215 of file PerturbativeDecayer.h.

Member Data Documentation

◆ inter_

ShowerInteraction Herwig::PerturbativeDecayer::inter_
private

Members for the generation of the hard radiation.

Which types of radiation to generate

Definition at line 260 of file PerturbativeDecayer.h.

◆ pT_

Energy Herwig::PerturbativeDecayer::pT_
private

Mmeber variables for the kinematics of the hard emission.

Transverse momentum of the emission

Definition at line 309 of file PerturbativeDecayer.h.


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