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Herwig 7.3.0
Herwig::SudakovFormFactor Class Reference

This is the definition of the Sudakov form factor class. More...

#include <SudakovFormFactor.h>

Inheritance diagram for Herwig::SudakovFormFactor:

Public Member Functions

 SudakovFormFactor ()
 The default constructor.
 
virtual ShoKinPtr generateNextTimeBranching (const Energy startingScale, const IdList &ids, const RhoDMatrix &rho, double enhance, double detuning)
 Members to generate the scale of the next branching.
 
virtual ShoKinPtr generateNextDecayBranching (const Energy startingScale, const Energy stoppingScale, const Energy minmass, const IdList &ids, const RhoDMatrix &rho, double enhance, double detuning)
 Return the scale of the next space-like decay branching.
 
virtual ShoKinPtr generateNextSpaceBranching (const Energy startingScale, const IdList &ids, double x, const RhoDMatrix &rho, double enhance, tcBeamPtr beam, double detuning)
 Return the scale of the next space-like branching.
 
virtual double generatePhiForward (ShowerParticle &particle, const IdList &ids, ShoKinPtr kinematics, const RhoDMatrix &rho)
 Generate the azimuthal angle of the branching for forward evolution.
 
virtual double generatePhiBackward (ShowerParticle &particle, const IdList &ids, ShoKinPtr kinematics, const RhoDMatrix &rho)
 Generate the azimuthal angle of the branching for backward evolution.
 
virtual double generatePhiDecay (ShowerParticle &particle, const IdList &ids, ShoKinPtr kinematics, const RhoDMatrix &rho)
 Generate the azimuthal angle of the branching for ISR in decays.
 
tSplittingFnPtr splittingFn () const
 Methods to provide public access to the private member variables.
 
tShowerAlphaPtr alpha () const
 Return the pointer to the ShowerAlpha object.
 
ShowerInteraction interactionType () const
 The type of interaction.
 
double z () const
 Methods to access the kinematic variables for the branching.
 
double phi () const
 The azimuthal angle.
 
Energy pT () const
 The transverse momentum.
 
double pdfMax () const
 Access the maximum weight for the PDF veto.
 
virtual Energy calculateScale (double z, Energy pt, IdList ids, unsigned int iopt)
 Method to return the evolution scale given the transverse momentum, \(p_T\) and \(z\).
 
- 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
 

Friends

class SplittingGenerator
 The SplittingGenerator is a friend to insert the particles in the branchings at initialisation.
 

Clone Methods.

SplittingFnPtr splittingFn_
 Pointer to the splitting function for this Sudakov form factor.
 
ShowerAlphaPtr alpha_
 Pointer to the coupling for this Sudakov form factor.
 
SudakovCutOffPtr cutoff_
 Pointer to the coupling for this Sudakov form factor.
 
double pdfmax_
 Maximum value of the PDF weight.
 
vector< IdListparticles_
 List of the particles this Sudakov is used for to aid in setting up interpolation tables if needed.
 
unsigned pdffactor_
 Option for the inclusion of a factor \(1/(1-z)\) in the PDF estimate.
 
double z_
 Member variables to keep the shower kinematics information generated by a call to generateNextTimeBranching or generateNextSpaceBranching.
 
double phi_
 The azimuthal angle.
 
Energy pT_
 The transverse momentum.
 
pair< double, double > zlimits_
 The limits of \(z\) in the splitting.
 
tcPDFPtr pdf_
 Stuff for the PDFs.
 
Energy freeze_
 Freezing scale.
 
Energy q_
 The evolution scale, \(\tilde{q}\).
 
IdList ids_
 The Ids of the particles in the current branching.
 
vector< Energy > masses_
 The masses of the particles in the current branching.
 
vector< Energy2 > masssquared_
 The mass squared of the particles in the current branching.
 
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.
 
SudakovFormFactoroperator= (const SudakovFormFactor &)=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.
 
void setPDF (tcPDFPtr pdf, Energy scale)
 Set the PDF.
 
const vector< Energy > & virtualMasses (const IdList &ids)
 Calculate the virtual masses for a branchings.
 
Energy2 pT2min ()
 The minimum pT2.
 
static void Init ()
 The standard Init function used to initialize the interfaces.
 
bool guessTimeLike (Energy2 &t, Energy2 tmin, double enhance, double detune)
 Methods to provide the next value of the scale before the vetos are applied.
 
bool guessDecay (Energy2 &t, Energy2 tmax, Energy minmass, double enhance, double detune)
 Value of the energy fraction and scale for time-like branching.
 
bool guessSpaceLike (Energy2 &t, Energy2 tmin, const double x, double enhance, double detune)
 Value of the energy fraction and scale for space-like branching.
 
void initialize (const IdList &ids, Energy2 &tmin)
 Initialize the values of the cut-offs and scales.
 
bool PSVeto (const Energy2 t)
 Phase Space veto member to implement the \(\Theta\) function as a veto so that the emission is within the allowed phase space.
 
bool computeTimeLikeLimits (Energy2 &scale)
 Compute the limits on \(z\) for time-like branching.
 
bool computeSpaceLikeLimits (Energy2 &scale, double x)
 Compute the limits on \(z\) for space-like branching.
 
void guesstz (Energy2 t1, unsigned int iopt, const IdList &ids, double enhance, bool ident, double detune, Energy2 &t_main, double &z_main)
 Methods to implement the veto algorithm to generate the scale of the next branching.
 
bool PDFVeto (const Energy2 t, const double x, const tcPDPtr parton0, const tcPDPtr parton1, tcBeamPtr beam) const
 Veto on the PDF for the initial-state shower.
 
double PDFVetoRatio (const Energy2 t, const double x, const tcPDPtr parton0, const tcPDPtr parton1, tcBeamPtr beam, double factor) const
 The PDF veto ratio.
 
bool SplittingFnVeto (const Energy2 t, const IdList &ids, const bool mass, const RhoDMatrix &rho, const double &detune) const
 The veto on the splitting function.
 
double SplittingFnVetoRatio (const Energy2 t, const IdList &ids, const bool mass, const RhoDMatrix &rho, const double &detune) const
 The Splitting function veto ratio.
 
bool alphaSVeto (Energy2 pt2) const
 The veto on the coupling constant.
 
double alphaSVetoRatio (Energy2 pt2, double factor) const
 The alpha S veto ratio.
 
void addSplitting (const IdList &)
 Set the particles in the splittings.
 
void removeSplitting (const IdList &)
 Delete the particles in the splittings.
 
const vector< IdList > & particles () const
 Access the potential branchings.
 

Additional Inherited Members

- 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 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 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

This is the definition of the Sudakov form factor class.

In general this is the base class for the implementation of Sudakov form factors in Herwig. The methods generateNextTimeBranching(), generateNextDecayBranching() and generateNextSpaceBranching need to be implemented in classes inheriting from this one.

In addition a number of methods are implemented to assist with the calculation of the form factor using the veto algorithm in classes inheriting from this one.

In general the Sudakov form-factor, for final-state radiation, is given by

\[\Delta_{ba}(\tilde{q}_{i+1},\tilde{q}_i)= \exp\left\{ -\int^{\tilde{q}^2_i}_{\tilde{q}^2_{i+1}} \frac{{\rm d}\tilde{q}^2}{\tilde{q}^2} \int\frac{\alpha_S(z,\tilde{q})}{2\pi} P_{ba}(z,\tilde{q})\Theta(p_T) \right\}. \]

We can solve this to obtain the next value of the scale \(\tilde{q}_{i+1}\) given the previous value \(\tilde{q}_i\) in the following way. First we obtain a simplified form of the integrand which is greater than or equal to the true integrand for all values of \(\tilde{q}\).

In practice it is easiest to obtain this over estimate in pieces. The ShowerAlpha object contains an over estimate for \(\alpha_S\), the splitting function contains both an over estimate of the spltting function and its integral which is needed to compute the over estimate of the \(\tilde{q}\) integrand, together with an over estimate of the limit of the \(z\) integral.

This gives an overestimate of the integrand

\[g(\tilde{q}^2) = \frac{c}{\tilde{q}^2}, \]

where because the over estimates are chosen to be independent of \(\tilde{q}\) the parameter

\[c = \frac{\alpha_{\rm over}}{2\pi}\int^{z_1}_{z_0}P_{\rm over}(z),\]

is a constant independent of \(\tilde{q}\).

The guesstz() member can then be used to generate generate the value of \(\tilde{q}^2\) according to this result. This is done by solving the Sudakov form factor, with the over estimates, is equal to a random number \(r\) in the interval \([0,1]\). This gives

\[\tilde{q}^2_{i+1}=G^{-1}\left[G(\tilde{q}^2_i)+\ln r\right],\]

where \(G(\tilde{q}^2)=c\ln(\tilde{q}^2)\) is the infinite integral of \(g(\tilde{q}^2)\) and \(G^{-1}(x)=\exp\left(\frac{x}c\right)\) is its inverse. It this case we therefore obtain

\[\tilde{q}^2_{i+1}=\tilde{q}^2_ir^{\frac1c}.\]

The value of \(z\) can then be calculated in a similar way

\[z = I^{-1}\left[I(z_0)+r\left(I(z_1)-I(z_0)\right)\right],\]

using the guesstz() member, where \(I=\int P(z){\rm d}z\) and \(I^{-1}\) is its inverse.

The veto algorithm then uses rejection using the ratio of the true value to the overestimated one to obtain the original distribution. This is accomplished using the

  • alphaSVeto() member for the \(\alpha_S\) veto
  • SplittingFnVeto() member for the veto on the value of the splitting function. in general there must also be a chech that the emission is in the allowed phase space but this is left to the inheriting classes as it will depend on the ordering variable.

The Sudakov form factor for the initial-scale shower is different because it must include the PDF which guides the backward evolution. It is given by

\[\Delta_{ba}(\tilde{q}_{i+1},\tilde{q}_i)= \exp\left\{ -\int^{\tilde{q}^2_i}_{\tilde{q}^2_{i+1}} \frac{{\rm d}\tilde{q}^2}{\tilde{q}^2} \int\frac{\alpha_S(z,\tilde{q})}{2\pi} P_{ba}(z,\tilde{q})\frac{x'f_a(\frac{x}z,\tilde{q}^2)}{xf_b(x,\tilde{q^2})} \right\}, \]

where \(x\) is the fraction of the beam momentum the parton \(b\) had before the backward evolution. This can be solve in the same way as for the final-state branching but the constant becomes

\[c = \frac{\alpha_{\rm over}}{2\pi}\int^{z_1}_{z_0}P_{\rm over}(z)PDF_{\rm max},\]

where

\[PDF_{\rm max}=\max\frac{x'f_a(\frac{x}z,\tilde{q}^2)}{xf_b(x,\tilde{q^2})},\]

which can be set using an interface. In addition the PDFVeto() member then is needed to implement the relevant veto.

See also
SplittingGenerator
SplittingFunction
ShowerAlpha
The interfaces defined for SudakovFormFactor.

Definition at line 127 of file SudakovFormFactor.h.

Constructor & Destructor Documentation

◆ SudakovFormFactor()

Herwig::SudakovFormFactor::SudakovFormFactor ( )
inline

The default constructor.

Definition at line 140 of file SudakovFormFactor.h.

Member Function Documentation

◆ alpha()

tShowerAlphaPtr Herwig::SudakovFormFactor::alpha ( ) const
inline

Return the pointer to the ShowerAlpha object.

Definition at line 238 of file SudakovFormFactor.h.

References alpha_.

◆ alphaSVeto()

bool Herwig::SudakovFormFactor::alphaSVeto ( Energy2  pt2) const
protected

The veto on the coupling constant.

Parameters
pt2The value of ther transverse momentum squared, \(p_T^2\).
Returns
true if vetoed

◆ clone()

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

Make a simple clone of this object.

Returns
a pointer to the new object.

Implements ThePEG::InterfacedBase.

Definition at line 507 of file SudakovFormFactor.h.

◆ computeSpaceLikeLimits()

bool Herwig::SudakovFormFactor::computeSpaceLikeLimits ( Energy2 &  scale,
double  x 
)
protected

Compute the limits on \(z\) for space-like branching.

Parameters
scaleThe scale of the particle
xThe energy fraction of the parton
Returns
True if lower limit less than upper, otherwise false

◆ computeTimeLikeLimits()

bool Herwig::SudakovFormFactor::computeTimeLikeLimits ( Energy2 &  scale)
protected

Compute the limits on \(z\) for time-like branching.

Parameters
scaleThe scale of the particle
Returns
True if lower limit less than upper, otherwise false

◆ fullclone()

virtual IBPtr Herwig::SudakovFormFactor::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.

Definition at line 513 of file SudakovFormFactor.h.

◆ generateNextDecayBranching()

virtual ShoKinPtr Herwig::SudakovFormFactor::generateNextDecayBranching ( const Energy  startingScale,
const Energy  stoppingScale,
const Energy  minmass,
const IdList ids,
const RhoDMatrix rho,
double  enhance,
double  detuning 
)
virtual

Return the scale of the next space-like decay branching.

If there is no branching then it returns ZERO.

Parameters
startingScalestarting scale for the evolution
stoppingScalestopping scale for the evolution
minmassThe minimum mass allowed for the spake-like particle.
idsThe PDG codes of the particles in the splitting defined.
enhanceThe radiation enhancement factor

◆ generateNextSpaceBranching()

virtual ShoKinPtr Herwig::SudakovFormFactor::generateNextSpaceBranching ( const Energy  startingScale,
const IdList ids,
double  x,
const RhoDMatrix rho,
double  enhance,
tcBeamPtr  beam,
double  detuning 
)
virtual

Return the scale of the next space-like branching.

If there is no branching then it returns ZERO.

Parameters
startingScalestarting scale for the evolution
idsThe PDG codes of the particles in the splitting
xThe fraction of the beam momentum defined.
beamThe beam particle
enhanceThe radiation enhancement factor

◆ generateNextTimeBranching()

virtual ShoKinPtr Herwig::SudakovFormFactor::generateNextTimeBranching ( const Energy  startingScale,
const IdList ids,
const RhoDMatrix rho,
double  enhance,
double  detuning 
)
virtual

Members to generate the scale of the next branching.

Return the scale of the next time-like branching. If there is no branching then it returns ZERO.

Parameters
startingScalestarting scale for the evolution
idsThe PDG codes of the particles in the splitting
enhanceThe radiation enhancement factor defined.

◆ generatePhiBackward()

virtual double Herwig::SudakovFormFactor::generatePhiBackward ( ShowerParticle particle,
const IdList ids,
ShoKinPtr  kinematics,
const RhoDMatrix rho 
)
virtual

Generate the azimuthal angle of the branching for backward evolution.

Parameters
particleThe branching particle
idsThe PDG codes of the particles in the branchings
TheShower kinematics

◆ generatePhiDecay()

virtual double Herwig::SudakovFormFactor::generatePhiDecay ( ShowerParticle particle,
const IdList ids,
ShoKinPtr  kinematics,
const RhoDMatrix rho 
)
virtual

Generate the azimuthal angle of the branching for ISR in decays.

Parameters
particleThe branching particle
idsThe PDG codes of the particles in the branchings
TheShower kinematics

◆ generatePhiForward()

virtual double Herwig::SudakovFormFactor::generatePhiForward ( ShowerParticle particle,
const IdList ids,
ShoKinPtr  kinematics,
const RhoDMatrix rho 
)
virtual

Generate the azimuthal angle of the branching for forward evolution.

Parameters
particleThe branching particle
idsThe PDG codes of the particles in the branchings
TheShower kinematics

◆ guessDecay()

bool Herwig::SudakovFormFactor::guessDecay ( Energy2 &  t,
Energy2  tmax,
Energy  minmass,
double  enhance,
double  detune 
)
protected

Value of the energy fraction and scale for time-like branching.

Parameters
tThe scale
tmaxThe maximum scale
minmassThe minimum mass of the particle after the branching
enhanceThe radiation enhancement factor

◆ guessSpaceLike()

bool Herwig::SudakovFormFactor::guessSpaceLike ( Energy2 &  t,
Energy2  tmin,
const double  x,
double  enhance,
double  detune 
)
protected

Value of the energy fraction and scale for space-like branching.

Parameters
tThe scale
tminThe minimum scale
xFraction of the beam momentum.
enhanceThe radiation enhancement factor

◆ guessTimeLike()

bool Herwig::SudakovFormFactor::guessTimeLike ( Energy2 &  t,
Energy2  tmin,
double  enhance,
double  detune 
)
protected

Methods to provide the next value of the scale before the vetos are applied.

Value of the energy fraction and scale for time-like branching

Parameters
tThe scale
tminThe minimum scale
enhanceThe radiation enhancement factor
Returns
False if scale less than minimum, true otherwise

◆ guesstz()

void Herwig::SudakovFormFactor::guesstz ( Energy2  t1,
unsigned int  iopt,
const IdList ids,
double  enhance,
bool  ident,
double  detune,
Energy2 &  t_main,
double &  z_main 
)
protected

Methods to implement the veto algorithm to generate the scale of the next branching.

Value of the energy fraction and value of the scale for the veto algorithm

Parameters
ioptThe option for calculating z
idsThe PDG codes of the particles in the splitting
  • 0 is final-state
  • 1 is initial-state for the hard process
  • 2 is initial-state for particle decays
t1The starting valoe of the scale
enhanceThe radiation enhancement factor
identicalWhether or not the outgoing particles are identical
t_mainrerurns the value of the energy fraction for the veto algorithm
z_mainreturns the value of the scale for the veto algorithm

◆ Init()

static void Herwig::SudakovFormFactor::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.

◆ initialize()

void Herwig::SudakovFormFactor::initialize ( const IdList ids,
Energy2 &  tmin 
)
protected

Initialize the values of the cut-offs and scales.

Parameters
tminThe minimum scale
idsThe ids of the partics in the branching

◆ interactionType()

ShowerInteraction Herwig::SudakovFormFactor::interactionType ( ) const
inline

The type of interaction.

Definition at line 243 of file SudakovFormFactor.h.

References splittingFn_.

◆ operator=()

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

The assignment operator is private and must never be called.

In fact, it should not even be implemented.

◆ particles()

const vector< IdList > & Herwig::SudakovFormFactor::particles ( ) const
inlineprotected

Access the potential branchings.

Definition at line 473 of file SudakovFormFactor.h.

References particles_.

◆ pdfMax()

double Herwig::SudakovFormFactor::pdfMax ( ) const
inline

Access the maximum weight for the PDF veto.

Definition at line 272 of file SudakovFormFactor.h.

References pdfmax_.

◆ PDFVeto()

bool Herwig::SudakovFormFactor::PDFVeto ( const Energy2  t,
const double  x,
const tcPDPtr  parton0,
const tcPDPtr  parton1,
tcBeamPtr  beam 
) const
protected

Veto on the PDF for the initial-state shower.

Parameters
tThe scale
xThe fraction of the beam momentum
parton0Pointer to the particleData for the new parent (this is the particle we evolved back to)
parton1Pointer to the particleData for the original particle
beamThe BeamParticleData object

◆ persistentInput()

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

Function used to write out object persistently.

Parameters
osthe persistent output stream written to.

◆ phi()

double Herwig::SudakovFormFactor::phi ( ) const
inline

The azimuthal angle.

Definition at line 261 of file SudakovFormFactor.h.

References phi_.

◆ PSVeto()

bool Herwig::SudakovFormFactor::PSVeto ( const Energy2  t)
protected

Phase Space veto member to implement the \(\Theta\) function as a veto so that the emission is within the allowed phase space.

Parameters
tThe scale
maxQ2The maximum virtuality
Returns
true if vetoed

◆ pT()

Energy Herwig::SudakovFormFactor::pT ( ) const
inline

The transverse momentum.

Definition at line 266 of file SudakovFormFactor.h.

References pT_.

◆ pT2min()

Energy2 Herwig::SudakovFormFactor::pT2min ( )
inline

The minimum pT2.

Definition at line 497 of file SudakovFormFactor.h.

References cutoff_.

◆ setPDF()

void Herwig::SudakovFormFactor::setPDF ( tcPDFPtr  pdf,
Energy  scale 
)
inline

Set the PDF.

Definition at line 480 of file SudakovFormFactor.h.

References freeze_, and pdf_.

◆ splittingFn()

tSplittingFnPtr Herwig::SudakovFormFactor::splittingFn ( ) const
inline

Methods to provide public access to the private member variables.

Return the pointer to the SplittingFunction object.

Definition at line 233 of file SudakovFormFactor.h.

References splittingFn_.

◆ SplittingFnVeto()

bool Herwig::SudakovFormFactor::SplittingFnVeto ( const Energy2  t,
const IdList ids,
const bool  mass,
const RhoDMatrix rho,
const double &  detune 
) const
inlineprotected

The veto on the splitting function.

Parameters
tThe scale
idsThe PDG codes of the particles in the splitting
massWhether or not to use the massive splitting functions
Returns
true if vetoed

Definition at line 424 of file SudakovFormFactor.h.

References ThePEG::UseRandom::rnd(), and SplittingFnVetoRatio().

◆ SplittingFnVetoRatio()

double Herwig::SudakovFormFactor::SplittingFnVetoRatio ( const Energy2  t,
const IdList ids,
const bool  mass,
const RhoDMatrix rho,
const double &  detune 
) const
inlineprotected

The Splitting function veto ratio.

Definition at line 436 of file SudakovFormFactor.h.

References splittingFn_, and z_.

Referenced by SplittingFnVeto().

◆ virtualMasses()

const vector< Energy > & Herwig::SudakovFormFactor::virtualMasses ( const IdList ids)
inline

Calculate the virtual masses for a branchings.

Definition at line 490 of file SudakovFormFactor.h.

References cutoff_.

◆ z()

double Herwig::SudakovFormFactor::z ( ) const
inline

Methods to access the kinematic variables for the branching.

The energy fraction

Definition at line 256 of file SudakovFormFactor.h.

References z_.

Friends And Related Function Documentation

◆ SplittingGenerator

friend class SplittingGenerator
friend

The SplittingGenerator is a friend to insert the particles in the branchings at initialisation.

Definition at line 133 of file SudakovFormFactor.h.

Member Data Documentation

◆ alpha_

ShowerAlphaPtr Herwig::SudakovFormFactor::alpha_
private

Pointer to the coupling for this Sudakov form factor.

Definition at line 534 of file SudakovFormFactor.h.

Referenced by alpha().

◆ cutoff_

SudakovCutOffPtr Herwig::SudakovFormFactor::cutoff_
private

Pointer to the coupling for this Sudakov form factor.

Definition at line 539 of file SudakovFormFactor.h.

Referenced by pT2min(), and virtualMasses().

◆ freeze_

Energy Herwig::SudakovFormFactor::freeze_
private

Freezing scale.

Definition at line 597 of file SudakovFormFactor.h.

Referenced by setPDF().

◆ ids_

IdList Herwig::SudakovFormFactor::ids_
private

The Ids of the particles in the current branching.

Definition at line 610 of file SudakovFormFactor.h.

◆ masses_

vector<Energy> Herwig::SudakovFormFactor::masses_
private

The masses of the particles in the current branching.

Definition at line 615 of file SudakovFormFactor.h.

◆ masssquared_

vector<Energy2> Herwig::SudakovFormFactor::masssquared_
private

The mass squared of the particles in the current branching.

Definition at line 620 of file SudakovFormFactor.h.

◆ particles_

vector<IdList> Herwig::SudakovFormFactor::particles_
private

List of the particles this Sudakov is used for to aid in setting up interpolation tables if needed.

Definition at line 550 of file SudakovFormFactor.h.

Referenced by particles().

◆ pdf_

tcPDFPtr Herwig::SudakovFormFactor::pdf_
private

Stuff for the PDFs.

PDf

Definition at line 592 of file SudakovFormFactor.h.

Referenced by setPDF().

◆ pdffactor_

unsigned Herwig::SudakovFormFactor::pdffactor_
private

Option for the inclusion of a factor \(1/(1-z)\) in the PDF estimate.

Definition at line 555 of file SudakovFormFactor.h.

◆ pdfmax_

double Herwig::SudakovFormFactor::pdfmax_
private

Maximum value of the PDF weight.

Definition at line 544 of file SudakovFormFactor.h.

Referenced by pdfMax().

◆ phi_

double Herwig::SudakovFormFactor::phi_
private

The azimuthal angle.

Definition at line 572 of file SudakovFormFactor.h.

Referenced by phi().

◆ pT_

Energy Herwig::SudakovFormFactor::pT_
private

The transverse momentum.

Definition at line 577 of file SudakovFormFactor.h.

Referenced by pT().

◆ q_

Energy Herwig::SudakovFormFactor::q_
private

The evolution scale, \(\tilde{q}\).

Definition at line 605 of file SudakovFormFactor.h.

◆ splittingFn_

SplittingFnPtr Herwig::SudakovFormFactor::splittingFn_
private

Pointer to the splitting function for this Sudakov form factor.

Definition at line 529 of file SudakovFormFactor.h.

Referenced by interactionType(), splittingFn(), and SplittingFnVetoRatio().

◆ z_

double Herwig::SudakovFormFactor::z_
private

Member variables to keep the shower kinematics information generated by a call to generateNextTimeBranching or generateNextSpaceBranching.

The energy fraction

Definition at line 567 of file SudakovFormFactor.h.

Referenced by SplittingFnVetoRatio(), and z().

◆ zlimits_

pair<double,double> Herwig::SudakovFormFactor::zlimits_
private

The limits of \(z\) in the splitting.

Definition at line 583 of file SudakovFormFactor.h.


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