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Herwig  7.1.5
Herwig::SMTopDecayer Class Reference

The SMTopDecayer performs decays of the top quark into the bottom quark and qqbar pairs or to the bottom quark and lepton neutrino pairs via W boson exchange. More...

#include <SMTopDecayer.h>

Inheritance diagram for Herwig::SMTopDecayer:

Public Member Functions

 SMTopDecayer ()
 The default constructor.
 
virtual int modeNumber (bool &, tcPDPtr, const tPDVector &) const
 Which of the possible decays is required.
 
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 double me2 (const int ichan, const Particle &part, const ParticleVector &decay, MEOption meopt) const
 Return the matrix element squared for a given mode and phase-space channel. More...
 
virtual WidthCalculatorBasePtr threeBodyMEIntegrator (const DecayMode &dm) const
 Method to return an object to calculate the 3 (or higher body) partial width. 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...
 
virtual void dataBaseOutput (ofstream &os, bool header) const
 Output the setup information for the particle database. More...
 
virtual bool hasMECorrection ()
 Virtual members to be overridden by inheriting classes which implement hard corrections. More...
 
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 (ShowerProgenitorPtr initial, ShowerParticlePtr parent, Branching br)
 Apply the soft matrix element correction. 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 Herwig::DecayIntegrator
 DecayIntegrator ()
 Default constructor.
 
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...
 
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 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...
 
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...
 
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 POWHEGType hasPOWHEGCorrection ()
 Has a POWHEG style correction.
 
virtual RealEmissionProcessPtr generateHardest (RealEmissionProcessPtr)
 Apply the POWHEG style correction.
 
- 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 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())
 
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 Member Functions

Energy6 dGammaIntegrand (Energy2 mffb2, Energy2 mbf2, Energy mt, Energy mb, Energy mf, Energy mfb, Energy mw) const
 The integrand for the integrate partial width.
 
vector< Lorentz5Momentum > applyHard (const ParticleVector &p, double, double)
 Apply the hard matrix element.
 
double getHard (double, double)
 Get the weight for hard emission.
 
double xgbr (int)
 This function is auxiliary to the function $x_{a}$ (hXAB).
 
double ktr (double, int)
 This function is auxiliary to the function $x_{a}$ (hXAB).
 
double xab (double, double, int)
 This function determines $x_{a}$ as a function of $x_{g}$ and $\kappa$ where $\kappa$ pertains to emissions from the b.
 
double xgbcut (double)
 This function determines the point ( $x_{g}$) where the condition that $x_{a}$ be real supersedes that due to the external input $\tilde{\kappa}$ where, again, $\kappa$ pertains to emissions from the b.
 
double xaccut (double)
 This function determines the minimum value of $x_{a}$ for a given $\tilde{\kappa}$ where $\kappa$ pertains to emissions from the c.
 
double z (double, double, int, int)
 This function is auxiliary to the function $x_{g}$ (hXGC).
 
double xgc (double, double, int, int)
 This function determines $x_{g}$ as a function of $x_{a}$ and $\kappa$ where $\kappa$ pertains to emissions from the c. More...
 
double xginvc0 (double, double)
 This function, $x_{g,c=0}^{-1}$, returns $x_{a}$ as a function of $x_{g}$ for the special case of c=0, for emissions from c (the b-quark). More...
 
double approxDeadMaxxa (double, double, double)
 For a given value of $x_{g}$ this returns the maximum value of $x_{a}$ in the dead region.
 
double approxDeadMinxa (double, double, double)
 For a given value of $x_{g}$ this returns the maximum value of $x_{a}$ in the dead region.
 
bool inTheAllowedRegion (double, double)
 This function returns true or false according to whether the values xg,xa are in the allowed region, the kinematically accessible phase space.
 
bool inTheApproxDeadRegion (double, double, double, double)
 This function returns true or false according to whether the values xg,xa are exactly in the approximate dead region.
 
bool inTheDeadRegion (double, double, double, double)
 This function returns true or false according to whether the values xg,xa are exactly in the dead region.
 
double deadRegionxgxa (double, double)
 This function returns values of ( $x_{g}$, $x_{a}$) distributed according to $\left(1+a-x_{a}\right)^{-1}x_{g}^{-2}$ in the approximate dead region.
 
LorentzRotation rotateToZ (Lorentz5Momentum)
 This rotation takes a 5-momentum and returns a rotation matrix such that it acts on the input 5-momentum so as to make it point in the +Z direction. More...
 
double me (double xw, double xg)
 Full matrix element with a factor of $\frac{\alpha_SC_F}{x_g^2\pi}$ removed. More...
 
ShowerAlphaPtr coupling ()
 Access to the strong coupling.
 
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...
 
Standard Interfaced functions.
virtual void doinit ()
 Initialize this object after the setup phase before saving and EventGenerator to disk. More...
 
virtual void doinitrun ()
 Initialize this object. More...
 
- 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.
 
- Protected Member Functions inherited from Herwig::HwDecayerBase
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
 InterfacedBase (string newName)
 
 InterfacedBase (const InterfacedBase &i)
 
virtual void readSetup (istream &is)
 
virtual void doupdate ()
 
virtual IVector getReferences ()
 
virtual void rebind (const TranslationMap &)
 
virtual void readSetup (istream &is)
 
virtual void doupdate ()
 
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

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

Private Attributes

AbstractFFVVertexPtr _wvertex
 Pointer to the W vertex.
 
PDPtr _wplus
 Pointer to the $W^\pm$.
 
RhoDMatrix _rho
 Spin density matrix for the decay.
 
vector< SpinorWaveFunction_inHalf
 1st spinor for the decay
 
vector< SpinorWaveFunction_outHalf
 2nd spinor for the decay
 
vector< SpinorBarWaveFunction_inHalfBar
 1st barred spinor for the decay
 
vector< SpinorBarWaveFunction_outHalfBar
 2nd barred spinor for the decay
 
Energy _ma
 The mass of the W boson.
 
Energy _mc
 The mass of the bottom quark.
 
Energy _mt
 The top mass.
 
Energy _mg
 The gluon mass.
 
double _a
 The mass ratio for the W.
 
double _c
 The mass ratio for the bottom.
 
double _g
 The mass ratio for the gluon.
 
double _ktb
 Two times the energy fraction of a.
 
double _ktc
 Two times the energy fraction of the gluon.
 
double _xg
 Two times the energy fraction of the gluon.
 
double _xa
 Two times the energy fraction of a.
 
double _xc
 Two times the energy fraction of c.
 
double _xg_sampling
 This determines the hard matrix element importance sampling in _xg. More...
 
double _initialenhance
 The enhancement factor for initial-state radiation.
 
double _finalenhance
 The enhancement factor for final-state radiation.
 
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.
 
ShowerAlphaPtr _alpha
 Pointer to the coupling.
 
vector< double > _wquarkwgt
 Max weight for integration. More...
 
vector< double > _wleptonwgt
 Weight $W\to \ell \nu$.
 

Static Private Attributes

static ClassDescription< SMTopDecayerinitSMTopDecayer
 The static object used to initialize the description of this class. More...
 

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 SMTopDecayer performs decays of the top quark into the bottom quark and qqbar pairs or to the bottom quark and lepton neutrino pairs via W boson exchange.

Definition at line 32 of file SMTopDecayer.h.

Member Function Documentation

◆ accept()

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

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

Uses the modeNumber member but can be overridden

Parameters
parentThe decaying particle
childrenThe decay products

Reimplemented from Herwig::DecayIntegrator.

◆ clone()

virtual IBPtr Herwig::SMTopDecayer::clone ( ) const
inlineprotectedvirtual

Make a simple clone of this object.

Returns
a pointer to the new object.

Implements ThePEG::InterfacedBase.

Reimplemented in Herwig::SMTopPOWHEGDecayer.

Definition at line 181 of file SMTopDecayer.h.

◆ dataBaseOutput()

virtual void Herwig::SMTopDecayer::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::DecayIntegrator.

◆ decay()

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

For a given decay mode and a given particle instance, perform the decay and return the decay products.

As this is the base class this is not implemented.

Returns
The vector of particles produced in the decay.

Reimplemented from Herwig::DecayIntegrator.

◆ doinit()

virtual void Herwig::SMTopDecayer::doinit ( )
protectedvirtual

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

Exceptions
InitExceptionif object could not be initialized properly.

Reimplemented from ThePEG::InterfacedBase.

◆ doinitrun()

virtual void Herwig::SMTopDecayer::doinitrun ( )
protectedvirtual

Initialize this object.

Called in the run phase just before a run begins.

Reimplemented from Herwig::DecayIntegrator.

◆ fullclone()

virtual IBPtr Herwig::SMTopDecayer::fullclone ( ) const
inlineprotectedvirtual

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.

Reimplemented in Herwig::SMTopPOWHEGDecayer.

Definition at line 187 of file SMTopDecayer.h.

◆ hasMECorrection()

virtual bool Herwig::SMTopDecayer::hasMECorrection ( )
inlinevirtual

Virtual members to be overridden by inheriting classes which implement hard corrections.

Has an old fashioned ME correction

Reimplemented from Herwig::HwDecayerBase.

Definition at line 51 of file SMTopDecayer.h.

◆ Init()

static void Herwig::SMTopDecayer::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.

◆ me()

double Herwig::SMTopDecayer::me ( double  xw,
double  xg 
)
protected

Full matrix element with a factor of $\frac{\alpha_SC_F}{x_g^2\pi}$ removed.

Parameters
xwThe momentum fraction of the W boson
xgThe momentum fraction of the gluon.

◆ me2()

virtual double Herwig::SMTopDecayer::me2 ( const int  ichan,
const Particle part,
const ParticleVector decay,
MEOption  meopt 
) const
virtual

Return the matrix element squared for a given mode and phase-space channel.

Parameters
ichanThe channel we are calculating the matrix element for.
partThe decaying Particle.
decayThe particles produced in the decay.
meoptOption for the calculation of the matrix element
Returns
The matrix element squared for the phase-space configuration.

Implements Herwig::DecayIntegrator.

◆ operator=()

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

The assignment operator is private and must never be called.

In fact, it should not even be implemented.

◆ persistentInput()

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

Function used to write out object persistently.

Parameters
osthe persistent output stream written to.

◆ rotateToZ()

LorentzRotation Herwig::SMTopDecayer::rotateToZ ( Lorentz5Momentum  )
protected

This rotation takes a 5-momentum and returns a rotation matrix such that it acts on the input 5-momentum so as to make it point in the +Z direction.

Finally it performs a randomn rotation about the z-axis.

◆ softMatrixElementVeto()

virtual bool Herwig::SMTopDecayer::softMatrixElementVeto ( ShowerProgenitorPtr  initial,
ShowerParticlePtr  parent,
Branching  br 
)
virtual

Apply the soft matrix element correction.

Parameters
initialThe particle from the hard process which started the shower
parentThe initial particle in the current branching
brThe branching struct
Returns
If true the emission should be vetoed

Reimplemented from Herwig::HwDecayerBase.

◆ threeBodydGammads()

virtual InvEnergy Herwig::SMTopDecayer::threeBodydGammads ( const int  imode,
const Energy2  q2,
const Energy2  s,
const Energy  m1,
const Energy  m2,
const Energy  m3 
) const
virtual

The differential three body decay rate with one integral performed.

Parameters
imodeThe mode for which the matrix element is needed.
q2The scale, i.e. the mass squared of the decaying particle.
sThe invariant mass which still needs to be integrate over.
m1The mass of the first outgoing particle.
m2The mass of the second outgoing particle.
m3The mass of the third outgoing particle.
Returns
The differential rate $\frac{d\Gamma}{ds}$

Reimplemented from Herwig::DecayIntegrator.

◆ threeBodyMEIntegrator()

virtual WidthCalculatorBasePtr Herwig::SMTopDecayer::threeBodyMEIntegrator ( const DecayMode dm) const
virtual

Method to return an object to calculate the 3 (or higher body) partial width.

Parameters
dmThe DecayMode
Returns
A pointer to a WidthCalculatorBase object capable of calculating the width

Reimplemented from Herwig::DecayIntegrator.

◆ xgc()

double Herwig::SMTopDecayer::xgc ( double  ,
double  ,
int  ,
int   
)
protected

This function determines $x_{g}$ as a function of $x_{a}$ and $\kappa$ where $\kappa$ pertains to emissions from the c.

It is multivalued, one selects a branch according to the second to last integer flag (+/-1). The last integer flag is used to select whether (1) or not (0) you wish to have the function for the special case of the full phase space, in which case the fifth argument $\kappa$ is irrelevant.

◆ xginvc0()

double Herwig::SMTopDecayer::xginvc0 ( double  ,
double   
)
protected

This function, $x_{g,c=0}^{-1}$, returns $x_{a}$ as a function of $x_{g}$ for the special case of c=0, for emissions from c (the b-quark).

The third input is $\tilde{\kappa}$ which pertains to emissions from c.

Member Data Documentation

◆ _wquarkwgt

vector<double> Herwig::SMTopDecayer::_wquarkwgt
private

Max weight for integration.

Weight $W\to q\bar{q}'$

Definition at line 362 of file SMTopDecayer.h.

◆ _xg_sampling

double Herwig::SMTopDecayer::_xg_sampling
private

This determines the hard matrix element importance sampling in _xg.

_xg_sampling=2.0 samples as 1/xg^2.

Definition at line 464 of file SMTopDecayer.h.

◆ initSMTopDecayer

ClassDescription<SMTopDecayer> Herwig::SMTopDecayer::initSMTopDecayer
staticprivate

The static object used to initialize the description of this class.

Indicates that this is a concrete class with persistent data.

Definition at line 342 of file SMTopDecayer.h.


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