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

#include <SudakovFormFactor.h>

Inheritance diagram for Herwig::SudakovFormFactor:

[legend]

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< IdList >	particles_
	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.

SudakovFormFactor &	operator= (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 &)

ReferenceCounted &	operator= (const ReferenceCounted &)

Protected Member Functions inherited from ThePEG::Named
const Named &	operator= (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

pt2	The 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

scale	The scale of the particle
x	The 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

scale The 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

startingScale	starting scale for the evolution
stoppingScale	stopping scale for the evolution
minmass	The minimum mass allowed for the spake-like particle.
ids	The PDG codes of the particles in the splitting defined.
enhance	The 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

startingScale	starting scale for the evolution
ids	The PDG codes of the particles in the splitting
x	The fraction of the beam momentum defined.
beam	The beam particle
enhance	The 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

startingScale	starting scale for the evolution
ids	The PDG codes of the particles in the splitting
enhance	The 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

particle	The branching particle
ids	The PDG codes of the particles in the branchings
The	Shower 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

particle	The branching particle
ids	The PDG codes of the particles in the branchings
The	Shower 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

particle	The branching particle
ids	The PDG codes of the particles in the branchings
The	Shower 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

t	The scale
tmax	The maximum scale
minmass	The minimum mass of the particle after the branching
enhance	The 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

t	The scale
tmin	The minimum scale
x	Fraction of the beam momentum.
enhance	The 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

t	The scale
tmin	The minimum scale
enhance	The 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

iopt	The option for calculating z
ids	The 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
t1	The starting valoe of the scale
enhance	The radiation enhancement factor
identical	Whether or not the outgoing particles are identical
t_main	rerurns the value of the energy fraction for the veto algorithm
z_main	returns 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

tmin	The minimum scale
ids	The 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

t	The scale
x	The fraction of the beam momentum
parton0	Pointer to the particleData for the new parent (this is the particle we evolved back to)
parton1	Pointer to the particleData for the original particle
beam	The BeamParticleData object

◆ persistentInput()

void Herwig::SudakovFormFactor::persistentInput	(	PersistentIStream &	is,
		int	version
	)

Function used to read in object persistently.

Parameters

is	the persistent input stream read from.
version	the version number of the object when written.

◆ persistentOutput()

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

Function used to write out object persistently.

Parameters

os	the 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

t	The scale
maxQ2	The 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

t	The scale
ids	The PDG codes of the particles in the splitting
mass	Whether 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:

SudakovFormFactor.h

Public Member Functions

Friends

Clone Methods.

Functions used by the persistent I/O system.

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ SudakovFormFactor()

Member Function Documentation

◆ alpha()

◆ alphaSVeto()

◆ clone()

◆ computeSpaceLikeLimits()

◆ computeTimeLikeLimits()

◆ fullclone()

◆ generateNextDecayBranching()

◆ generateNextSpaceBranching()

◆ generateNextTimeBranching()

◆ generatePhiBackward()

◆ generatePhiDecay()

◆ generatePhiForward()

◆ guessDecay()

◆ guessSpaceLike()

◆ guessTimeLike()

◆ guesstz()

◆ Init()

◆ initialize()

◆ interactionType()

◆ operator=()

◆ particles()

◆ pdfMax()

◆ PDFVeto()

◆ persistentInput()

◆ persistentOutput()

◆ phi()

◆ PSVeto()

◆ pT()

◆ pT2min()

◆ setPDF()

◆ splittingFn()

◆ SplittingFnVeto()

◆ SplittingFnVetoRatio()

◆ virtualMasses()

◆ z()

Friends And Related Function Documentation

◆ SplittingGenerator

Member Data Documentation

◆ alpha_

◆ cutoff_

◆ freeze_

◆ ids_

◆ masses_

◆ masssquared_

◆ particles_

◆ pdf_

◆ pdffactor_

◆ pdfmax_

◆ phi_

◆ pT_

◆ q_

◆ splittingFn_

◆ z_

◆ zlimits_